Comparison of adsorption equilibrium models for the study of CL-, NO3- and SO4(2-) removal from aqueous solutions by an anion exchange resin.

PubMed

Dron, Julien; Dodi, Alain

2011-06-15

The removal of chloride, nitrate and sulfate ions from aqueous solutions by a macroporous resin is studied through the ion exchange systems OH(-)/Cl(-), OH(-)/NO(3)(-), OH(-)/SO(4)(2-), and HCO(3)(-)/Cl(-), Cl(-)/NO(3)(-), Cl(-)/SO(4)(2-). They are investigated by means of Langmuir, Freundlich, Dubinin-Radushkevitch (D-R) and Dubinin-Astakhov (D-A) single-component adsorption isotherms. The sorption parameters and the fitting of the models are determined by nonlinear regression and discussed. The Langmuir model provides a fair estimation of the sorption capacity whatever the system under study, on the contrary to Freundlich and D-R models. The adsorption energies deduced from Dubinin and Langmuir isotherms are in good agreement, and the surface parameter of the D-A isotherm appears consistent. All models agree on the order of affinity OH(-)

Processes of Molecular Relaxation in Binary Crystalline Systems KNO3-KClO4, KNO3-KNO2, and K2CO3-K2SO4

NASA Astrophysics Data System (ADS)

Aliev, A. R.; Akhmedov, I. R.; Kakagasanov, M. G.; Aliev, Z. A.; Gafurov, M. M.; Rabadanov, K. Sh.; Amirov, A. M.

2018-03-01

The processes of molecular relaxation in binary crystalline systems KNO3-KClO4, KNO3-KNO2, and K2CO3-K2SO4 are studied via differential thermal analysis and Raman spectroscopy. It is found that the relaxation time of the vibrations ν1( A) of anions NO- 3 and CO2- 3 in systems KNO3-KClO4, KNO3-KNO2, and K2CO3-K2SO4 is less than that in KNO3 and K2CO3, respectively. It is shown that the increased rate of relaxation is explained by an additional relaxation mechanism presented in the system. This mechanism is associated with the excitation of vibrations of anions ClO- 4, NO- 2, and SO2- 4 and the lattice phonons that emerge. It is found that this relaxation mechanism requires correspondence of the frequency difference of these vibrations to the region of sufficiently high density of states of the phonon spectrum.

[Pollution characteristics and source of the atmospheric fine particles and secondary inorganic compounds at Mount Dinghu in autumn season].

PubMed

Liu, Zi-Rui; Wang, Yue-Si; Liu, Quan; Liu, Lu-Ning; Zhang, De-Qiang

2011-11-01

Real-time measurements of PM2.5, secondary inorganic compounds in PM2.5 (SO4(2-), NH4(+), and NO3(-)) and related gaseous pollutants were conducted at Mount Dinghu, a regional background station of the Pearl River Delta (PRD), in October and November 2008 by using a conventional R&P TEOM and a system of rapid collection of fine particles and ion chromatography (RCFP-IC). Sources and transportation of atmospheric particles during the experiment were discussed with principal component analysis and backward trajectories calculated using HYSPLIT model. The average daily mass concentrations of PM2.5 were 76.9 microg x m(-3) during sampling period, and average daily mass concentrations of SO4(2-), NH4(+), and NO3(-) were 20.0 microg x m(-3), 6.8 microg x m(-3) and 2.6 microg x m(-3), respectively. The sum of these three secondary inorganic compounds accounted for more than one third of the PM2.5 mass concentration, which had become the major source of atmospheric fine particles at Mount Dinghu. The diurnal variation of PM2.5, SO4(2-), and NH4(+) all showed a "bimodal" distribution with two peaks appeared at 10:00 am and at 16:00 pm, respectively, whereas NO3(-s) howed "single peak" distribution peaked at 10:00 am. The mass concentrations of SO4(2-) in PM2.5 had the similar diurnal variation with that of SO2, SO4(2-) in PM2.5 was mainly transformed from SO2, whereas NO3(-) showed difference diurnal variation with that of NO2, and the second conversion rate of NO2 was far lower than that of SO2. NH4(+) in PM2.5 existed mainly in the form of sulfate, nitrate and chloride. Both of principal component analysis and back trajectory analysis showed that the variations of PM2.5 and secondary inorganic compounds at Mount Dinghu were mainly affected by the long-range transport air mass passed over Guangzhou, Huizhou and other highly industrialized areas which carried air pollutants to the observation site, at the same time local sulfate originated from secondary formation also contributed an important part of atmospheric fine particles and the contribution from local direct emission was little.

Winter measurements of trace gas and aerosol composition at a rural site in southern ontario

NASA Astrophysics Data System (ADS)

Daum, P. H.; Kelly, T. J.; Tanner, R. L.; Tang, X.; Anlauf, K.; Bottenheim, J.; Brice, K. A.; Wiebe, H. A.

This paper reports the results of continuous measurements of concentrations of trace gas and aerosol species at Powassan, Ontario, a rural location in southern Ontario, from 20 January to 24 February 1984. The measurements included aerosol H + , NH 4+, Na +, Ca 2+ , NO 3-, SO 42- and Cl -, gaseous SO 2, NO, NO' y; ( = NO + NO2 + PAN + HNO3), HNO 3, PAN, and O 3. Average values of concentrations for key species during the project were: SO 2, 7.3 ppb; NO y, 7.5 ppb; HNO 3, 0.85 ppb; O 3, 33 ppb; NH 4+ 1.5 ppb; NO 3-, 0.4 ppb; and SO 42-, 0.9 ppb. Concentrations of primary pollutants (e.g. SO 2) were typically much higher, and concentrations of secondary species (e.g. SO 42-) typically lower, than observed at this location in summer. However, clear-air t- NO 3-/SO 42- ratios averaged 5-10 times higher in winter than in summer which suggests that HNO 3 is a more important source of atmospheric acidity, relative to SO 42- aerosol, in winter than in summer. Pollutant concentrations were highly variable; back trajectory calculations indicate that periods of high concentrations of both primary and secondary species were typically associated with air-mass back trajectories from the southern sectors while periods of low concentrations of secondary species were associated with back trajectories from the north. Comparison of these measurements with those at other locations suggests that concentrations at Powassan were characteristic of those prevailing over a much larger, possibly regional, area.

Ferric Sulfate and Proline Enhance Heavy-Metal Tolerance of Halophilic/Halotolerant Soil Microorganisms and Their Bioremediation Potential for Spilled-Oil Under Multiple Stresses

PubMed Central

Al-Mailem, Dina M.; Eliyas, Mohamed; Radwan, Samir S.

2018-01-01

The aim of this study was to explore the heavy-metal resistance and hydrocarbonoclastic potential of microorganisms in a hypersaline soil. For this, hydrocarbonoclastic microorganisms were counted on a mineral medium with oil vapor as a sole carbon source in the presence of increasing concentrations of ZnSO4, HgCl2, CdSO4, PbNO3, CuSO4, and Na2HAsO4. The colony-forming units counted decreased in number from about 150 g-1 on the heavy-metal-free medium to zero units on media with 40–100 mg l-1 of HgCl2, CdSO4, PbNO3, or Na2HAsO4. On media with CuSO4 or ZnSO4 on the other hand, numbers increased first reaching maxima on media with 50 mg l-1 CuSO4 and 90 mg l-1 ZnSO4. Higher concentrations reduced the numbers, which however, still remained considerable. Pure microbial isolates in cultures tolerated 200–1600 mg l-1 of HgCl2, CdSO4, PbNO3, CuSO4, and Na2HAsO4 in the absence of crude oil. In the presence of oil vapor, the isolates tolerated much lower concentrations of the heavy metals, only 10–80 mg l-1. The addition of 10 Fe2(SO4)3 and 200 mg l-1 proline (by up to two- to threefold) enhanced the tolerance of several isolates to heavy metals, and consequently their potential for oil biodegradation in their presence. The results are useful in designing bioremediation technologies for oil spilled in hypersaline areas. PMID:29563904

Evaluation of aerosol composition changes in the last 60 years around southeastern Greenland by analyzing micro-inclusions in the SE-Dome ice core using Raman spectroscopy.

NASA Astrophysics Data System (ADS)

Ando, T.; Iizuka, Y.; Ohno, H.; Sugiyama, S.

2017-12-01

Emission regulation of anthropogenic NOX and SOX since late 90's rather caused excess atmospheric ammonium (NH3) in agricultural regions (Warner et al., 2017, Geophys. Res. Lett.). The Arctic is one of the most sensitive areas for future warming. Aerosols in the Arctic are transported from the Northern Hemisphere and mostly experience wet deposition (Breider et al., 2014, Jour. of Geophys. Res.: Atmos.). Ice cores preserve past water-soluble aerosols. From these viewpoints, ice cores from the Arctic is suitable to evaluate recent variation in aerosol composition due to human activity in the Northern Hemisphere and aerosol transportation. We analyzed ion concentrations in the ice core samples from a southeastern dome in Greenland (SE-Dome). The concentrations increased for NH4+ and decreased for SO42- after late 90's. The NH4+ increasing trend is due to excess NH3 emission in North America. Cloud nuclei formation depends on chemical form of aerosols. Thus, differences in chemical forms of these ammonium aerosols in SE-Dome samples are important to evaluate the effect on climate change in Greenland. In this study, we identified the chemical form of aerosols (water-soluble inclusions) in the SE-Dome ice core by using micro-Raman spectroscopy. SE-Dome ice core samples were collected in 2015 and enabled us to reconstruct seasonal variation owing to extremely higher accumulation rate ( 1m/yr.). The ice samples were sublimated and accumulated inclusions on the Ni sheets in a clean booth under -22 degrees Celsius. We identified CaSO4, Na2SO4, (NH4)2SO4, NaNO3, NH4NO3 by Raman spectra. This is the first report to identify ammonium salts ((NH4)2SO4 and NH4NO3) from ice core sample. In the summer samples, the relative abundances of CaSO4 and NaNO3 are lower but (NH4)2SO4 are higher than those in the spring samples. NH4+ rapidly react with SO24- under higher temperature. Higher concentration of NH3 in the warmest season possibly enhanced the formation of (NH4)2SO4 in North America and/or transportation of (NH4)2SO4 to the Arctic. Interestingly, (NH4)2SO4 are not detected from the spring samples deposited after late 90's while NH4NO3 are observed. Reduction of SOX emission since late 90's presumably reduced (NH4)2SO4 formation in North America agricultural regions and its transportation to the Arctic such as Greenland.

[Composition and source of atmosphere aerosol water soluble ions over the East China Sea in winter].

PubMed

He, Yu-Hui; Yang, Gui-Peng; Zhang, Hong-Hai

2011-08-01

With the ion chromatographic method, the water-soluble ion concentrations of Cl(-), NO3(-), SO4(2-) , CH3SO3(-) (MSA), Na+, K+, NH4+, Mg2+ and Ca2+ in the atmospheric aerosol over the East China Sea in winter 2009 was determined and the sources of these ions was investigated through correlation analysis by SPSS (statistical package for social sciences) software. The results indicated that the concentrations of secondary ions in aerosol were the highest (non-sea-salt sulfates nss-SO4(2-), NO3(-), NH4+), accounting for 78.4% of total determining ions. The calculation results of equivalent concentration of anions and cations showed that the acid ions of aerosol were neutralized inadequately. The stoichiometry of NH4+ in different compounds showed that NH4HSO4 was the main binding form of NH4+ and SO4(2-) in the aerosol. The concentration of methanesulfonic acid (MSA) was low, and the average value was (0.0088 +/- 0.0037) microg x m(-3). According to calculation, the contribution of sea-salt sulfates was 4.5% to total sulfates, and that of biogenous sulfates was 1.4% to non-sea-salt sulfate (nss-SO4(2-)), showing that human input was the main source of sulfates in aerosol over the East China Sea. In addition, nss-SO4(2-)/NO3(-) in the aerosol was 1.08, reflecting that China's energy structure adjustment played an important role in recent years.

Matrix based fertilizers reduce nitrogen and phosphorus leaching in three soils.

PubMed

Entry, James A; Sojka, R E

2008-05-01

We compared the efficacy of matrix based fertilizers (MBFs) formulated to reduce NO3-, NH4+, and total phosphorus (TP) leaching, with Osmocoate 14-14-14, a conventional commercial slow release fertilizer (SRF) and an unamended control in three different soil textures in a greenhouse column study. The MBFs covered a range of inorganic N and P in compounds that are relatively loosely bound (MBF 1) to more moderately bound (MBF 2) and more tightly bound compounds (MBF 3) mixed with Al(SO4)3H2O and/or Fe2(SO4)3 and with high ionic exchange compounds starch, chitosan and lignin. When N and P are released, the chemicals containing these nutrients in the MBF bind N and P to a Al(SO4)3H2O and/or Fe2(SO4)3 starch-chitosan-lignin matrix. One milligram (8000 spores) of Glomus intradices was added to all formulations to enhance nutrient uptake. In all three soil textures the SRF leachate contained a higher amount of NH4+, NO3- and TP than leachate from all other fertilizers. In all three soils there were no consistent differences in the amount of NH4+, NO3- and TP in the MBF leachates compared to the control leachate. Plants growing in soils receiving SRF had greater shoot, root and total biomass than all MBFs regardless of Al(SO4)3H2O or Fe2(SO4)3 additions. Arbuscular mycorrhizal infection in plant roots did not consistently differ among plants growing in soil receiving SRF, MBFs and control treatments. Although the MBFs resulted in less plant growth in this experiment they may be applied to soils growing plants in areas that are at high risk for nutrient leaching to surface waters.

The ion chemistry, seasonal cycle, and sources of PM 2.5 and TSP aerosol in Shanghai

NASA Astrophysics Data System (ADS)

Wang, Ying; Zhuang, Guoshun; Zhang, Xingying; Huang, Kan; Xu, Chang; Tang, Aohan; Chen, Jianmin; An, Zhisheng

Daily total suspended particulate (TSP), particle size smaller than 100 μm and particle size smaller than 2.5 μm (PM 2.5) aerosol samples were collected at two sites in Shanghai in four seasons from September 2003 to January 2005. Concentrations of the water-soluble ions (SO 42-, NO 3-, Cl -, F -, PO 43-, HCOO -, CH 3COO -, NO 2-, MSA, C 2O 42-, NH 4+, Ca 2+, Na +, K +, Mg 2+) were measured for a total of 202 samples. Daily TSP and PM 2.5 mass concentrations ranged from 66.1 to 666.8 μg m -3 and 17.8 to 217.9 μg m -3, with annual average concentrations of 230.5 and 94.6 μg m -3, respectively. The sum of ions contributed an average of 26% and 32% of TSP and PM 2.5 mass concentrations, respectively. In PM 2.5, the concentration of the major ions followed the order of SO 42->NO 3->NH 4+>Cl ->Ca 2+>K +, while in TSP was SO 42->NO 3->Cl ->Ca 2+>NH 4+>Na +. These major ions were mainly in the form of (NH 4) 2SO 4, Ca(NO 3) 2, CaCl 2, and CaSO 4 in aerosol particles. The aerosol was slightly acidic in the fine particle size range, and alkaline in the coarse mode. Seasonal variation of ion concentrations was significant, with the highest concentrations observed in winter and spring and the lowest in summer and autumn. Three types of air masses, i.e. marine, mixing, and continental, were frequently observed, and their distribution in four seasons might result in the clear seasonal variation. It is Shanghai that has the highest NO 3-/SO 42- value among all of those cities in China, indicating that as the biggest city in China the mobile source of the air pollution becomes more and more predominant. However, stationary emissions were still the dominant source in Shanghai indicated by the NO 3-/SO 42- ratio of lower than 1. The formation of NO 3- was largely from the gas-phase photochemical reaction in the cold season, and from the heterogeneous reaction in the warm season, while the formation of SO 42- might be from the heterogeneous reaction in the entire year round. NH 4+, K +, Cl -, NO 3-, and SO 42- were mainly influenced by the anthropogenic emissions in land, meanwhile Cl - and SO 42- might be partly influenced by the sea. Na +, Mg 2+, and Ca 2+ were derived from both inland crustal and marine sources. Chloride depletion was found especially in summer. The air pollution in Shanghai has proved to be under the influence of both the local emissions and the long-range transport from outside areas.

Surface tensions of inorganic multicomponent aqueous electrolyte solutions and melts.

PubMed

Dutcher, Cari S; Wexler, Anthony S; Clegg, Simon L

2010-11-25

A semiempirical model is presented that predicts surface tensions (σ) of aqueous electrolyte solutions and their mixtures, for concentrations ranging from infinitely dilute solution to molten salt. The model requires, at most, only two temperature-dependent terms to represent surface tensions of either pure aqueous solutions, or aqueous or molten mixtures, over the entire composition range. A relationship was found for the coefficients of the equation σ = c(1) + c(2)T (where T (K) is temperature) for molten salts in terms of ion valency and radius, melting temperature, and salt molar volume. Hypothetical liquid surface tensions can thus be estimated for electrolytes for which there are no data, or which do not exist in molten form. Surface tensions of molten (single) salts, when extrapolated to normal temperatures, were found to be consistent with data for aqueous solutions. This allowed surface tensions of very concentrated, supersaturated, aqueous solutions to be estimated. The model has been applied to the following single electrolytes over the entire concentration range, using data for aqueous solutions over the temperature range 233-523 K, and extrapolated surface tensions of molten salts and pure liquid electrolytes: HCl, HNO(3), H(2)SO(4), NaCl, NaNO(3), Na(2)SO(4), NaHSO(4), Na(2)CO(3), NaHCO(3), NaOH, NH(4)Cl, NH(4)NO(3), (NH(4))(2)SO(4), NH(4)HCO(3), NH(4)OH, KCl, KNO(3), K(2)SO(4), K(2)CO(3), KHCO(3), KOH, CaCl(2), Ca(NO(3))(2), MgCl(2), Mg(NO(3))(2), and MgSO(4). The average absolute percentage error between calculated and experimental surface tensions is 0.80% (for 2389 data points). The model extrapolates smoothly to temperatures as low as 150 K. Also, the model successfully predicts surface tensions of ternary aqueous mixtures; the effect of salt-salt interactions in these calculations was explored.

The chemistry of the severe acidic precipitation in Shanghai, China

NASA Astrophysics Data System (ADS)

Huang, Kan; Zhuang, Guoshun; Xu, Chang; Wang, Ying; Tang, Aohan

2008-07-01

Seventy-six rain samples from forty-seven rain events and TSP aerosol samples throughout the entire year of 2005 were collected in Shanghai, China. The annual mean pH in rain was 4.49 with the lowest pH of 2.95, and the frequency of acid rain was 71% in 2005. The acidity of rain increased more than 15 times in the past 8 years compared to 1997. The volume-weighted mean ionic concentrations of the acidic ions, SO 42- and NO 3- in rainwater were 199.59 and 49.80 μeq/L with maximum of 832.67 and 236.59 μeq/L, respectively. The concentration of SO 42- was higher than the most polluted cities abroad, indicating Shanghai has been a severe polluted city over the world. The high coal/fuel consumption from urbanization and the rapid increase of vehicles resulted in the high emission of SO 2 and NO x, the precursor of the high concentration of acidic ions, SO 42- and NO 3-, which were the main reason of the severe acid rain in Shanghai. The major ions showed clear temporal variations with higher concentrations of SO 42-, NO 3-, NH 4+, and Ca 2+ in spring/winter, of Na +, Cl -, K +, and Mg 2+ in autumn, and the lowest of all the ions in summer. SO 42- and NO 3- were mainly in the form of CaSO 4 and Ca(NO 3) 2, which showed the dominant neutralization effect of Ca 2+ over NH 4+. Source identification indicated that SO 42-, NO 3-, NH 4+ and most Ca 2+ derived from anthropogenic sources, K +, Mg 2+ and partial Ca 2+ originated from mineral, and almost all the Cl - and Na + from the sea. The chemistry of precipitation in Shanghai was under the influence of local pollution sources and the long- and moderate-range transport through back trajectory analysis.

Aerosol chemical composition and light scattering during a winter season in Beijing

NASA Astrophysics Data System (ADS)

Tao, Jun; Zhang, Leiming; Gao, Jian; Wang, Han; Chai, Faihe; Wang, Shulan

2015-06-01

To evaluate PM2.5 contributions to light scattering under different air pollution levels, PM2.5 and its major chemical components, PM10, size-segregated water-soluble ions, and aerosol scattering coefficient (bsp) under dry conditions were measured at an urban site in Beijing in January 2013 when heavy pollution events frequently occurred. Measurements were categorized into three pollution levels including heavy-polluted (Air Quality Index (AQI) ≥ 200), light-polluted (200 > AQI ≥ 100) and clean periods (AQI < 100). The average PM2.5 mass concentration was 248 μg m-3 during the heavy-polluted period, which was 2.4 and 5.6 times of those during the light-polluted (104 μg m-3) and clean (44 μg m-3) periods, respectively. The concentrations of SO42-, NO3- and NH4+ increased much more than those of OC and EC during the heavy-polluted period compared with those during the light-polluted and clean periods. Good correlations between PM2.5 and bsp were found (R2 > 0.95) during the different pollution levels. The mass scattering efficiency (MSE) of PM2.5 was 4.9 m2 g-1 during the heavy-polluted period, which was higher than those during the light-polluted (4.3 m2 g-1) and clean periods (3.6 m2 g-1). To further evaluate the impact of individual chemical components of PM2.5 on light scattering, a multiple linear regression equation of measured bsp against the mass concentration of (NH4)2SO4, NH4NO3, Organic Matter (OM), EC, Fine Soil (FS), Coarse Matter (CM) and Other chemical compounds were performed. (NH4)2SO4, NH4NO3 and OM were the dominant species contributing to bsp under both dry and ambient conditions. OM contributed more to bsp than the sum of (NH4)2SO4 and NH4NO3 did under the dry condition during all the pollution periods and this was also the case under the ambient condition during the light-polluted and clean periods. However, the total contributions of (NH4)2SO4 and NH4NO3 to bsp under the ambient condition was 55%, much more than the 29% contribution from OM during the heavy-polluted period. High (NH4)2SO4 and NH4NO3 concentrations and their hygroscopicity were the main reasons causing visibility degradation during the heavy-polluted period, and the effect can be enhanced under high RH conditions.

Thermodynamic modeling of Cl(-), NO3(-) and SO4(2-) removal by an anion exchange resin and comparison with Dubinin-Astakhov isotherms.

PubMed

Dron, Julien; Dodi, Alain

2011-03-15

The removal of chloride, nitrate, and sulfate ions from wastewaters by a macroporous ion-exchange resin is studied through the experimental results obtained for six ion exchange systems, OH(-)/Cl(-), OH(-)/NO3(-), OH(-)/SO4(2-), and HCO3(-)/Cl(-), Cl(-)/NO3(-), Cl(-)/SO4(2-). The results are described through thermodynamic modeling, considering either an ideal or a nonideal behavior of the ionic species in the liquid and solid phases. The nonidealities are determined by the Davies equation and Wilson equations in the liquid and solid phases, respectively. The results show that the resin has a strong affinity for all the target ions, and the order of affinity obtained is OH(-) < HCO3(-) < Cl(-) < NO3(-) < SO4(2-). The calculation of the changes in standard Gibbs free energies (ΔG(0)) shows that even though HCO3(-) has a lower affinity to the resin, it may affect the removal of Cl(-), and in the same way that Cl(-) may affect the removal of NO3(-) and SO4(2-). The application of nonidealities in the thermodynamic model leads to an improved fit of the model to the experimental data with average relative deviations below 1.5% except for the OH(-)/SO4(2-) system. On the other hand, considering ideal or nonideal behaviors has no significant impact on the determination of the selectivity coefficients. The thermodynamic modeling is also compared with the Dubinin-Astakhov adsorption isotherms obtained for the same ion exchange systems. Surprisingly, the latter performs significantly better than the ideal thermodynamic model and nearly as well as the nonideal thermodynamic model.

Identification of Calcium Sulphoaluminate Formation between Alunite and Limestone

PubMed Central

Kim, Hyung-Seok; Han, Gi-Chun; Ahn, Ji-Whan; Cho, Kye-Hong; Cho, Hee-Chan

2009-01-01

This study was carried out to identify the conditions of formation of calcium sulphoaluminate (3CaO·3Al2O3·CaSO4) by the sintering of a limestone (CaCO3) and alunite [K2SO4·Al2(SO4)3·4Al(OH)3] mixture with the following reagents: K2SO4, CaCO3, Al(OH)3, CaSO4·2H2O, and SiO2. When K2SO4, CaCO3, Al(OH)3, CaSO4·2H2O were mixed in molar ratios of 1:3:6:3 and sintered at 1,200∼1,300 °C, only 3CaO·3Al2O3·CaSO4 and calcium langbeinite (2CaSO4·K2SO4) were generated. With an amount of CaO that is less than the stoichiometric molar ratio, 3CaO·3Al2O3·CaSO4 was formed and anhydrite (CaSO4) did not react and remained behind. With the amount of CaSO4 that is less than the stoichiometric molar ratio, the amounts of 3CaO·3Al2O3·CaSO4 and 2CaSO4·K2SO4 decreased, and that of CaO·Al2O3 increased. In the K2SO4-CaO-Al2O3-CaSO4-SiO2 system, to stabilize the formation of 3CaO·3Al2O3·CaSO4, 2CaSO4·K2SO4, and β-2CaO·SiO2, the molar ratios of CaO: Al2O3: CaSO4 must be kept at 3:3:1 and that of CaO/SiO2, over 2.0; otherwise, the generated amount of 3CaO·3Al2O3·CaSO4 decreased and that of gehlenite (2CaO·Al2O3·SiO2) with no hydration increased quantitatively. Therefore, if all SO3(g) generated by the thermal decomposition of alunite reacts with CaCO3 (or CaO, the thermal decomposition product of limestone) to form CaSO4 in an alunite- limestone system, 1 mol of pure alunite reacts with 6 mol of limestone to form 1 mol of 3CaO·3Al2O3·CaSO4 and 1 mol of 2CaSO4·K2SO4. PMID:22346687

Fabrication and luminescent properties of La2O2S:Eu3+ translucent ceramic by pressureless reaction sintering

NASA Astrophysics Data System (ADS)

Lian, Jingbao; Wang, Bingxin; Liang, Ping; Liu, Feng; Wang, Xuejiao

2014-04-01

La2O2S:Eu3+ translucent ceramic (LOS:Eu) was fabricated by pressureless reaction sintering method. It is found that the (La, Eu)2(OH)4SO4ṡ2H2O precursor is synthesized by co-precipitation using commercially available La(NO3)3, Eu(NO3)3, (NH4)2SO4 and NH3ṡH2O as the starting materials. And this precursor can be converted into pure La2O2SO4:Eu3+ phosphor by calcination at 800 °C for 1 h in air, which is composed of a few small needle agglomerated particles. Then the La2O2SO4:Eu3+ phosphor compact can be sintered into the LOS:Eu at 1500 °C for 2 h in the hybrid atmosphere of flowing hydrogen and argon. Under 387 nm UV light excitation, the LOS:Eu reveals a red light emission at 628 nm as the most prominent peak, which corresponds to the 5D0 → 7F2 transition of Eu3+ ions.

2D Hybrid Nanomaterials for Selective Detection of NO2 and SO2 Using "Light On and Off" Strategy.

PubMed

Chen, Aimin; Liu, Rui; Peng, Xiao; Chen, Qiaofen; Wu, Jianmin

2017-10-25

In order to distinguish NO 2 and SO 2 gas with one sensor, we designed a paper chip assembled with a 2D g-C 3 N 4 /rGO stacking hybrid fabricated via a layer-by-layer self-assembly approach. The g-C 3 N 4 /rGO hybrid exhibited a remarkable photoelectric property due to the construction of a van der Waals heterostructure. For the first time, we have been able to selectively detect NO 2 and SO 2 gas using a "light on and off" strategy. Under the "light off" condition, the g-C 3 N 4 /rGO sensor exhibited a p-type semiconducting behavior with a low detection limit of 100 ppb of NO 2 , but with no response toward SO 2 . In contrast, the sensor showed n-type semiconducting behavior which could detect SO 2 at concentration as low as 2 ppm under UV light irradiation. The effective electron transfer among the 2D structure of g-C 3 N 4 and rGO nanosheets as well as highly porous structures could play an important role in gas sensing. The different sensing mechanisms at "light on and off" circumstances were also investigated in detail.

Boundary layer measurements of the OH radical in the vicinity of an isolated power plant plume - SO2 and NO2 chemical conversion times

NASA Technical Reports Server (NTRS)

Davis, D. D.; Philen, D.; Mcgee, T.; Heaps, W.

1979-01-01

Direct measurements of the OH radical in the vicinity of an isolated power plant plume are reported. These measurements were used to estimate the conversion time of SO2 to H2SO4-sulfate aerosol via the initiating step OH + SO2 + M yields HSO3. Using the near-high-noon measured value of OH (9.5 million per cu cm), resulted in a 1/e conversion time of 1.4 days. The latter lifetime would correspond to a conversion rate of about 2%/hr. When the lifetime calculation was modified to take into consideration the OH diurnal cycle, the 1/e conversion time for SO2 was found to be 4.4 days, giving an apparent overall rate of conversion of about 0.7%/hr. Similar calculations carried out for the conversion of NO2 to NHO3 resulted in 1/e lifetimes for NO2 of 2-3 h for midday time periods.

Acidity of Aerosols during Winter Heavy Haze Events in Beijing and Gucheng, China

NASA Astrophysics Data System (ADS)

Chi, Xiyuan; He, Pengzhen; Jiang, Zhuang; Yu, Xiawei; Yue, Fange; Wang, Longquan; Li, Bokun; Kang, Hui; Liu, Cheng; Xie, Zhouqing

2018-02-01

We investigated the acidity and concentrations of water-soluble ions in PM2.5 aerosol samples collected from an urban site in Beijing and a rural site in Gucheng, Hebei Province from November 2016 to January 2017 to gain an insight into the formation of secondary inorganic species. The average SO4 2-, NO3 -, and NH4 + concentrations were 8.3, 12.5, and 14.1 μg m-3, respectively, at the urban site and 14.0, 14.2, and 24.2 μg m-3, respectively, at the rural site. The nitrogen and sulfur oxidation ratios in urban Beijing were correlated with relative humidity (with correlation coefficient r = 0.79 and 0.67, respectively) and the aerosol loadings. Based on a parameterization model, we found that the rate constant of the heterogeneous reactions for SO2 on polluted days was about 10 times higher than that on clear days, suggesting that the heterogeneous reactions in the aerosol water played an essential role in haze events. The ISORROPIA II model was used to predict the aerosol pH, which had a mean (range) of 5.0 (4.9-5.2) and 5.3 (4.6-6.3) at the urban and rural site, respectively. Under the conditions with this predicted pH value, oxidation by dissolved NO2 and the hydrolysis of N2O5 may be the major heterogeneous reactions forming SO4 2- and NO3 - in haze. We also analyzed the sensitivity of the aerosol pH to changes in the concentrations of SO4 2-, NO3 -, and NH4 + under haze conditions. The aerosol pH was more sensitive to the SO4 2- and NH4 + concentrations with opposing trends, than to the NO3 - concentrations. The sensitivity of the pH was relatively weak overall, which was attributed to the buffering effect of NH3 partitioning.

Gas-phase ammonia and PM2.5 ammonium in a busy traffic area of Nanjing, China.

PubMed

Wang, Wenxin; Wang, Shanshan; Xu, Jianhua; Zhou, Rui; Shi, Chanzhen; Zhou, Bin

2016-01-01

The gas-phase ammonia (NH3) and fine particle PM2.5 ammonium (pNH4(+)) (collectively, NHx) were monitored between July 2013 and August 2014 in a busy traffic area of Nanjing, China. Results showed that PM2.5 concentration was 66.7 μg m(-3), and NH3 concentration was 6.66 μg m(-3). In the PM2.5, the concentration of pNH4(+) was 3.04 μg m(-3), SO4(2-) (pSO4(2-)) was 10.16 μg m(-3), and NO3(-) (pNO3(-)) was 1.60 μg m(-3). The significant correlation curves from the tests of PM2.5 revealed that molar ratio of pNH4(+) and pSO4(2-) was approximately 2, which could be (NH4)2SO4. Particulate NH4(+) primarily associated with pSO4(2-), which accounted for 4.54% of total PM2.5 mass. The PM2.5 observed acidic and the NH3 in the atmosphere neutralized acidic species, mainly in a sulfate form. The traffic intensity in the region was partially related to the formation of PM2.5 and NH3, suggesting that traffic pollution may be an important source of PM2.5. The reaction between NHx and acidic species was assumed to the secondary PM2.5. The neutralization and photochemical property of NHx were discussed.

The Impact of Template Types on Polyeugenol to the Adsorption Selectivity of Ionic Imprinted Polymer (IIP) Fe Metal Ion

NASA Astrophysics Data System (ADS)

Djunaidi, M. C.; Haris, A.; Pardoyo; Rosdiana, K.

2018-04-01

The synthesis of IIP was carried out by variation of Fe(III) ion templates from Fe(NO3)3, K3[Fe(CN)6] and NH4Fe(SO4)2 compounds which then tested IIP selectivity to the Fe metal ions through adsorption process. Ionic Imprinted Polymer (IIP) is a method of printing metal ions bound in a polymer, subsequently released from the polymer matrix to produce a suitable imprint for the target ion. The purposes of this study were to produce IIP from Fe(NO3)3, K3[Fe(CN)6] and NH4Fe(SO4)2 templates, to know the effect of templates on adsorption selectivity of IIP involving imprint cavity, and to know the impact of metal competitor on the selectivity adsorption of IIP to the Fe metals. The results obtained showed that IIP synthesized by variations of Fe(NO3)3, K3[Fe(CN)6] and NH4Fe(SO4)2 templates were successfully synthesized. The adsorption selectivity of Fe (III) metal ion in the Fe(NO3)3 template was greater than that of in the K3[Fe(CN)6] and NH4Fe(SO4)2 templates. The adsorption selectivity of Fe was greater on Fe-Cr compared to on Fe-Cd and Fe-Pb.

Comparisons of plutonium, thorium, and cerium tellurite sulfates.

PubMed

Lin, Jian; Cross, Justin N; Diwu, Juan; Meredith, Nathan A; Albrecht-Schmitt, Thomas E

2013-04-15

The hydrothermal reaction of PuCl3 or CeCl3 with TeO2 in the presence of sulfuric acid under the comparable conditions results in the crystallization of Pu(TeO3)(SO4) or Ce2(Te2O5)(SO4)2, respectively. Pu(TeO3)(SO4) and its isotypic compound Th(TeO3)(SO4) are characterized by a neutral layer structure with no interlamellar charge-balancing ions. However, Ce2(Te2O5)(SO4)2 possesses a completely different dense three-dimensional framework. Bond valence calculation and UV-vis-NIR spectra indicate that the Ce compound is trivalent whereas the Pu and Th compounds are tetravalent leading to the formation of significantly different compounds. Pu(TeO3)(SO4), Th(TeO3)(SO4), and Ce2(Te2O5)(SO4)2 represent the first plutonium/thorium/cerium tellurite sulfate compounds. Our study strongly suggests that the chemistries of Pu and Ce are not the same, and this is another example of the failure of Ce as a surrogate.

Method for reducing CO2, CO, NOX, and SOx emissions

DOEpatents

Lee, James Weifu; Li, Rongfu

2002-01-01

Industrial combustion facilities are integrated with greenhouse gas-solidifying fertilizer production reactions so that CO.sub.2, CO, NO.sub.x, and SO.sub.x emissions can be converted prior to emission into carbonate-containing fertilizers, mainly NH.sub.4 HCO.sub.3 and/or (NH.sub.2).sub.2 CO, plus a small fraction of NH.sub.4 NO.sub.3 and (NH.sub.4).sub.2 SO.sub.4. The invention enhances sequestration of CO.sub.2 into soil and the earth subsurface, reduces N0.sub.3.sup.- contamination of surface and groundwater, and stimulates photosynthetic fixation of CO.sub.2 from the atmosphere. The method for converting CO.sub.2, CO, NO.sub.x, and SO.sub.x emissions into fertilizers includes the step of collecting these materials from the emissions of industrial combustion facilities such as fossil fuel-powered energy sources and transporting the emissions to a reactor. In the reactor, the CO.sub.2, CO, N.sub.2, SO.sub.x, and/or NO.sub.x are converted into carbonate-containing fertilizers using H.sub.2, CH.sub.4, or NH.sub.3. The carbonate-containing fertilizers are then applied to soil and green plants to (1) sequester inorganic carbon into soil and subsoil earth layers by enhanced carbonation of groundwater and the earth minerals, (2) reduce the environmental problem of NO.sub.3.sup.- runoff by substituting for ammonium nitrate fertilizer, and (3) stimulate photosynthetic fixation of CO.sub.2 from the atmosphere by the fertilization effect of the carbonate-containing fertilizers.

NOx promotion of SO2 conversion to sulfate: An important mechanism for the occurrence of heavy haze during winter in Beijing.

PubMed

Ma, Jinzhu; Chu, Biwu; Liu, Jun; Liu, Yongchun; Zhang, Hongxing; He, Hong

2018-02-01

In this study, concentrations of NO x , SO 2 , O 3 and fine particles (PM 2.5 ) were measured at three monitoring stations in Beijing during 2015. For extreme haze episodes during 25 Nov. - 3 Dec. 2015, observation data confirmed that high concentrations of NO x promoted the conversion of SO 2 to sulfate. Annual data confirmed that this is an important mechanism for the occurrence of heavy haze during winter in Beijing. Furthermore, in situ perturbation experiments in a potential aerosol mass (PAM) reactor were carried out at Shengtaizhongxin (STZX) station during both clean and polluted days. The concentrations of SO 4 2- , NH 4 + , NO 3 - and organic aerosol were positively related to the concentration of added NO 2 . These results provide definitive evidence that NO 2 can promote the conversion of SO 2 to sulfate. At the same time, we found that NO 2 can promote the formation of NH 4 + and organic compounds in the aerosols. Our results illustrate that strengthened controls of nitrogen oxides is a key step in reducing the fine particles level in China. Copyright © 2017 Elsevier Ltd. All rights reserved.

Hydration of the sulfuric acid-methylamine complex and implications for aerosol formation.

PubMed

Bustos, Danielle J; Temelso, Berhane; Shields, George C

2014-09-04

The binary H2SO4-H2O nucleation is one of the most important pathways by which aerosols form in the atmosphere, and the presence of ternary species like amines increases aerosol formation rates. In this study, we focus on the hydration of a ternary system of sulfuric acid (H2SO4), methylamine (NH2CH3), and up to six waters to evaluate its implications for aerosol formation. By combining molecular dynamics (MD) sampling with high-level ab initio calculations, we determine the thermodynamics of forming H2SO4(NH2CH3)(H2O)n, where n = 0-6. Because it is a strong acid-base system, H2SO4-NH2CH3 quickly forms a tightly bound HSO4(-)-NH3CH3(+) complex that condenses water more readily than H2SO4 alone. The electronic binding energy of H2SO4-NH2CH3 is -21.8 kcal mol(-1) compared with -16.8 kcal mol(-1) for H2SO4-NH3 and -12.8 kcal mol(-1) for H2SO4-H2O. Adding one to two water molecules to the H2SO4-NH2CH3 complex is more favorable than adding to H2SO4 alone, yet there is no systematic difference for n ≥ 3. However, the average number of water molecules around H2SO4-NH2CH3 is consistently higher than that of H2SO4, and it is fairly independent of temperature and relative humidity.

Synthesis of cationic iridium(I) complexes of water-soluble phosphine ligands, [Ir(CO)(TPPMS){sub 3}]CF{sub 3}SO{sub 3}, [Ir(CO)(H{sub 2}O)(TPPTS){sub 2}]CF{sub 3}SO{sub 3}, and [Ir(CO){sub 2}(TPPMS){sub 3}]ClO{sub 4} (TPPMS = PPh{sub 2}(m-C{sub 6}H{sub 4}SO{sub 3}K), TPPTS = P(m-C{sub 6}H{sub 4}SO{sub 3}Na){sub 3})

DOE Office of Scientific and Technical Information (OSTI.GOV)

Paterniti, D.P.; Francisco, L.W.; Atwood, J.D.

Several new water-soluble iridium(I) complexes were synthesized and their reactivities with small molecules (H{sub 2} or CO) in polar solvents (DMSO or H{sub 2}O) examined. Reaction of H{sub 2} with [Ir(CO)(TPPMS){sub 3}]CF{sub 3}SO{sub 3} (TPPMS = P(C{sub 6}H{sub 5}){sub 2}(m-C{sub 6}H{sub 4}SO{sub 3}K)) in DMSO or H{sub 2}O produces [cis,mer-Ir(CO)(H){sub 2}(TPPMS){sub 3}]CF{sub 3}SO{sub 3}, while the reaction of CO with [Ir(CO)(TPPMS){sub 3}]-CF{sub 3}SO{sub 3} in water yields [Ir(CO){sub 2}(TPPMS){sub 3}]CF{sub 3}SO{sub 3}. Carbonylation of [Ir(CO){sub 2}(TPPMS){sub 3}]ClO{sub 4} in DMSO produces [Ir(CO){sub 3}(TPPMS){sub 2}]ClO{sub 4} and TPPMS; no reaction is observed in H{sub 2}O. Hydrogenation of [Ir(CO){sub 2}(TPPMS){sub 3}]ClO{sub 4}more » in DMSO or H{sub 2}O yields [cis,mer-Ir(CO)(H){sub 2}(TPPMS){sub 3}]ClO{sub 4}, while reaction of H{sub 2} with an aqueous solution of [Ir(CO)(H{sub 2}O)(TPPTS){sub 2}]CF{sub 3}SO{sub 3} produces [Ir(CO)(H{sub 2}O)(H){sub 2}(TPPTS){sub 2}]CF{sub 3}SO{sub 3}. Reaction of trans-Ir(CO)ClL{sub 2} (L = TPPMS or TPPTS) with excess L in H{sub 2}O produces [Ir(CO)L{sub 3}]Cl, while no reaction occurs in DMSO, [Ir(CO){sub 3}(TPPMS){sub 2}]Cl reacts irreversibly with TPPMS in H{sub 2}O to produce [Ir(CO){sub 2}-(TPPMS){sub 3}]Cl.« less

Ammonia Partitioning into the Condensed Phase in Winter Time Conditions

NASA Astrophysics Data System (ADS)

Green, J. R.; Bililign, S.; Fiddler, M. N.; Leen, J. B.; Holloway, J. S.; Fibiger, D. L.; McDuffie, E. E.; Thornton, J. A.; Brown, S. S.

2015-12-01

Secondary aerosol (SOA) formation has been linked to health problems and environmental damage in regions impacted by the emission of gaseous NH3 and SO2. SOA formation, (NH4)2SO4 and NH4NO3, in the presence of NO NO2, is favored under high relative humidity and low temperature and low temperature conditions. In the East and Mid Atlantic regions of the United States humidity is low in wintertime. Utilizing ambient concentration data of gaseous NO, NO2, SO2 and NH3 collected aboard a survey aircraft we examined the partitioning of gaseous NH3 towards aerosol products. The calculated mixing ratio of gaseous SO2/NH3 correlated with relative humidity will give an indication of the potential SOA formation when the mixing ratio of other reactants is small in the region of interest. The data obtained originates from a series of night and day survey flights on a C-130 aircraft that occurred from February 3 to March 13, 2015 over the Eastern coastal region of the United States extending from New York to Florida. NOx was obtained from the Airborne Ring-down Nitrogen Oxide Laser Detector (ARNOLD) instrument (NOAA) and Thermal Dissociation-Laser Induced Fluorescence (TD-LIF) (UC Berkley). SO2 measurements were done using the TECO 43C SO2 analyzer and for NH3 measurements the an Ammonia Analyzer - Trace (NH3) (Los Gatos Research). Estimates of aerosol dry deposition fluxes are presented.

Ionic composition of TSP and PM 2.5 during dust storms and air pollution episodes at Xi'an, China

NASA Astrophysics Data System (ADS)

Shen, Zhenxing; Cao, Junji; Arimoto, Richard; Han, Zhiwei; Zhang, Renjian; Han, Yuemei; Liu, Suixin; Okuda, Tomoaki; Nakao, Shunsuke; Tanaka, Shigeru

TSP and PM 2.5 samples were collected at Xi'an, China during dust storms (DSs) and several types of pollution events, including haze, biomass burning, and firework displays. Aerosol mass concentrations were up to 2 times higher during the particulate matter (PM) events than on normal days (NDs), and all types of PM led to decreased visibility. Water-soluble ions (Na +, NH 4+, K +, Mg 2+, Ca 2+, F -, Cl -, NO 3-, and SO 42-). were major aerosol components during the pollution episodes, but their concentrations were lower during DSs. NH 4+, K +, F -, Cl -, NO 3-, and SO 42- were more abundant in PM 2.5 than TSP but the opposite was true for Mg 2+ and Ca 2+. PM collected on hazy days was enriched with secondary species (NH 4+, NO 3-, and SO 42) while PM from straw combustion showed high K + and Cl -. Firework displays caused increases in K + and also enrichments of NO 3- relative to SO 42-. During DSs, the concentrations of secondary aerosol components were low, but Ca 2+ was abundant. Ion balance calculations indicate that PM from haze and straw combustion was acidic while the DSs samples were alkaline and the fireworks' PM was close to neutral. Ion ratios (SO 42-/K +, NO 3-/SO 42-, and Cl -/K +) proved effective as indicators for different pollution episodes.

Heat capacities and entropies from 8 to 1000 K of langbeinite (K2Mg2(SO4)3), anhydrite (CaSO4) and of gypsum (CaSO4·2H2O)

USGS Publications Warehouse

Robie, Richard A.; Russell-Robinson, Susan; Hemingway, Bruce S.

1989-01-01

Although Bond (Bell Sys. Tech. J., 22 (1943) 145) reported that langbeinite was piezoelectric at room temperature, we found no evidence in our Cpo measurements for a Curie temperature above which langbeinite would no longer be piezoelectric.

Synergistic reaction between SO2 and NO2 on mineral oxides: a potential formation pathway of sulfate aerosol.

PubMed

Liu, Chang; Ma, Qingxin; Liu, Yongchun; Ma, Jinzhu; He, Hong

2012-02-07

Sulfate is one of the most important aerosols in the atmosphere. A new sulfate formation pathway via synergistic reactions between SO(2) and NO(2) on mineral oxides was proposed. The heterogeneous reactions of SO(2) and NO(2) on CaO, α-Fe(2)O(3), ZnO, MgO, α-Al(2)O(3), TiO(2), and SiO(2) were investigated by in situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (in situ DRIFTS) at ambient temperature. Formation of sulfate from adsorbed SO(2) was promoted by the coexisting NO(2), while surface N(2)O(4) was observed as the crucial oxidant for the oxidation of surface sulfite. This process was significantly promoted by the presence of O(2). The synergistic effect between SO(2) and NO(2) was not observed on other mineral particles (such as CaCO(3) and CaSO(4)) probably due to the lack of the surface reactive oxygen sites. The synergistic reaction between SO(2) and NO(2) on mineral oxides resulted in the formation of internal mixtures of sulfate, nitrate, and mineral oxides. The change of mixture state will affect the physicochemical properties of atmospheric particles and therefore further influence their environmental and climate effects.

Simple analysis of atmospheric NO{sub 2}, SO{sub 2}, and O{sub 3} in mountains by using passive samplers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yamada, Etsu; Kimura, Mitsuo; Tomozawa, Kenichi

1999-12-01

A simple analysis of atmospheric NO{sub 2}, SO{sub 2}, and O{sub 3} in mountains by passive samplers was investigated and applied to the spatial analysis of air pollutants at Mt. Hiei in Kyoto City, Passive samplers were exposed for 30 days. Yanagisawa-type samplers were used for NO{sub 2} determination. The absorbed NO{sub 2} was measured as nitrite ion spectro-photometrically by the Saltzman method. On the other hand, SO{sub 2} samplers comprising an absorbent filter containing sodium carbonate solution were made. The absorbed SO{sub 2} was oxidized to SO{sub 4}{sup 2{minus}} with an H{sub 2}O{sub 2} solution and determined by ionmore » chromatography. For O{sub 3} determination, Ogawa ozone samplers were used. The O{sub 3} reacted with nitrite ion to produce nitrate ion, which was measured by ion chromatography. The relative standard deviations for NO{sub 2}, SO{sub 2}, and O{sub 3} samplers were 1.4%, 3--10%, and 2--5%, respectively. Samplers were set up in 13 locations at Mt. Hiei. The NO{sub 2} concentration and its distribution along the slope of Mt. Hiei changed considerably both daily and seasonally. The seasonal variation of atmospheric NO{sub 2} showed a winter maximum and a summer minimum. The concentration of atmospheric SO{sub 2} at Mt. Hiei was lower than that of NO{sub 2} and scarcely changed. Atmospheric O{sub 3} increased gradually with an increase of the altitude, exhibiting a regular pattern with a maximum in spring and a minimum in winter.« less

Heavy haze episodes in Beijing during January 2013: Inorganic ion chemistry and source analysis using highly time-resolved measurements from an urban site.

PubMed

Han, Bin; Zhang, Rui; Yang, Wen; Bai, Zhipeng; Ma, Zhiqiang; Zhang, Wenjie

2016-02-15

The heavy air pollution that occurred in Beijing in January of 2013 attracted intense attention around the world. During this period, we conducted highly time-resolved measurements of inorganic ions associated with PM2.5 at an urban site of Beijing, and investigated ion chemistry and potential sources. Hourly concentrations of Cl(-), NO3(-), SO4(2-), Na(+), NH4(+), K(+), Mg(2+), and Ca(2+) were measured. Peak concentrations of SO4(2-) and NO3(-) were observed on the 10th-15th, 21st-24th, and the 26th-30th during this monitoring campaign. The percentages of SO4(2-) and NH4(+) in total ion concentration increased with the enhancement of PM2.5 concentrations, indicating that high concentrations of SO4(2-) and NH4(+) may play important roles in the formation of haze episodes. The ratio of [NO3(-)]/[SO4(2-)] was calculated, revealing that the sources of SO4(2-) would contribute more to the formation of PM2.5 than mobile sources. Diurnal variations of SO4(2-), NO3(-), NH4(+) (SNA) exhibited a similar pattern, with high concentrations at night and low levels during the day, revealing that meteorological conditions, such as mixing layer height, relative humidity, were likely to be responsible for high levels of SNA at night. The roles of meteorological conditions were further discussed in the formation of secondary inorganic ions. Relative humidity and temperature played key roles and exhibited positive correlations with secondary inorganic ions. An aerosol inorganics simulation model showed that SNA existed mainly in the aqueous phase during the sampling period. Furthermore, potential sources were identified by applying positive matrix factorization model. Secondary nitrate, secondary sulfate, coal combustion and biomass burning, as well as fugitive dust, were considered to be major contributors to total ions. Copyright © 2015. Published by Elsevier B.V.

The promotion effect of coexisting hygroscopic composition on the reaction between oxalic acid and calcite during humidifying process

NASA Astrophysics Data System (ADS)

Ma, Q.; He, H.

2012-12-01

Internally mixed oxalic acid with mineral dust has been frequently detected in field measurements (Sullivan and Prather, 2007; Wang et al., 2012; Yang et al., 2009). Meanwhile, Furukawa and Takahashi (Furukawa and Takahashi, 2011) found that most of the oxalic acid in mineral mixture is present as metal oxalate complexes in the aerosols, however, the formation mechanism of these complexes is not well known. It was reported that cloud process of H2C2O4/CaCO3 mixture could lead to the formation of calcium oxalate (Gierlus et al., 2012). Recently, we used Raman spectroscopy to investigate the hygroscopic behavior of H2C2O4/CaCO3 mixture below saturation condition as well as the effect of coexisting hygroscopic compositions, e.g. Ca(NO3)2, NaCl, NH4NO3, and (NH4)2SO4. It was found that there was no interaction between H2C2O4 and calcite without third component during humidifying process under ambient condition. In contrast, the presence of coexisting Ca(NO)3, NaCl, or NH4NO3 could promote the reaction between H2C2O4 and calcite by providing an aqueous circumstance after deliquescence, resulting in the formation of calcium oxalate hydrates. Moreover, substitution of strong acid (HNO3) by medium acid (H2C2O4) occurred when water vapor was absorbed in Ca(NO3)2/H2C2O4 mixture (Ma and He, 2012). As for (NH4)2SO4, there existed a competition effect between (NH4)2SO4 and H2C2O4 for the reaction with CaCO3. CaCO3 was preferentially reacted with (NH4)2SO4 to form gypsum in the solution, while the residual NH4+ and C2O42- ions were bonded to (NH4)2C2O4 after efflorescence. These results implies a potential formation pathway of metal oxalate complexes in the atmosphere and also suggests that synergistic effect between different constituents in humidifying process of mixed particles should be considered in future hygroscopic behavior studies.

Specific ion-protein interactions dictate solubility behavior of a monoclonal antibody at low salt concentrations.

PubMed

Zhang, Le; Zhang, Jifeng

2012-09-04

The perturbation of salt ions on the solubility of a monoclonal antibody was systematically studied at various pHs in Na(2)SO(4), NaNO(3), NaCl, NaF, MgSO(4), Mg(NO(3))(2) and MgCl(2) solutions below 350 mM. At pH 7.1, close to the pI, all of the salts increased the solubility of the antibody, following the order of SO(4)(2-) > NO(3)(-) > Cl(-) > F(-) for anions and Mg(2+) > Na(+) for cations. At pH 5.3 where the antibody had a net positive charge, the anions initially followed the order of SO(4)(2-) > NO(3)(-) > Cl(-) > F(-) for effectiveness in reducing the solubility and then switched to increasing the solubility retaining the same order. Furthermore, the antibody was more soluble in the Mg(2+) salt solutions than in the corresponding Na(+) salt solutions with the same anion. At pH 9.0 where the antibody had a net negative charge, an initial decrease in the protein solubility was observed in the solutions of the Mg(2+) salts and NaF, but not in the rest of the Na(+) salt solutions. Then, the solubility of the antibody was increased by the anions in the order of SO(4)(2-) > NO(3)(-) > Cl(-) > F(-). The above complex behavior is explained based on the ability of both cation and anion from a salt to modulate protein-protein interactions through their specific binding to the protein surface.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Luo, Qianqian; Han, Ying; Lin, Hechun, E-mail: hclin@ee.ecnu.edu.cn

One dimensional coordination polymer Gd[(SO{sub 4})(NO{sub 3})(C{sub 2}H{sub 6}SO){sub 2}] (1) is prepared through the mediation of Bronsted acid ionic liquid, which crystallized in the monoclinic space of C2/c. In this polymer, adjacent Gd atoms are linked by two SO{sub 4}{sup 2-} ions to generate a 1-D chain, and all oxygen atoms in SO{sub 4}{sup 2-} groups are connected to three nearest Gd atoms in µ{sup 3}:η{sup 1}:η{sup 1}:η{sup 2} fashion. Gd, S and N from SO{sub 4}{sup 2-} and NO{sub 3}{sup -} are precisely coplanar. The planar is coordinated by a pair of DMSO molecules, which is parallel andmore » linked by hydrogen bonding to form a three-dimensional supramolecular network. Magnetic susceptibility measurement of 1 reveals weak antiferromagnetic interactions between the Gd (III) ions. It exhibits relatively large magneto-caloric effect with –ΔS{sub m}=28.8 J Kg{sup −1} K{sup −1} for ΔH=7 T. - Graphical abstract: Coordination polymer Gd[(SO{sub 4})(NO{sub 3})(C{sub 2}H{sub 6}SO){sub 2}] was obtained mediated by Bronsted acid Ionic Liquid, which presents a 1-D chains collected by SO{sub 4}{sup 2-} groups. Magnetic susceptibility of the polymer reveals weak antiferromagnetic interactions between the Gd(III) ions with the relatively large magneto-caloric effect of –ΔS{sub m}=28.8 J Kg{sup −1} K{sup −1} for ΔH= 7T.« less

Neutron scattering studies of K3H(SO4)2 and K3D(SO4)2: the particle-in-a-box model for the quantum phase transition.

PubMed

Fillaux, François; Cousson, Alain

2012-08-21

In the crystal of K(3)H(SO(4))(2) or K(3)D(SO(4))(2), dimers SO(4)···H···SO(4) or SO(4)···D···SO(4) are linked by strong centrosymmetric hydrogen or deuterium bonds whose O···O length is ≈2.50 Å. We address two open questions. (i) Are H or D sites split or not? (ii) Is there any structural counterpart to the phase transition observed for K(3)D(SO(4))(2) at T(c) ≈ 85.5 K, which does not exist for K(3)H(SO(4))(2)? Neutron diffraction by single-crystals at cryogenic or room temperature reveals no structural transition and no resolvable splitting of H or D sites. However, the width of the probability densities suggest unresolved splitting of the wavefunctions suggesting rigid entities H(L1/2)-H(R1/2) or D(L1/2)-D(R1/2) whose separation lengths are l(H) ≈ 0.16 Å or l(D) ≈ 0.25 Å. The vibrational eigenstates for the center of mass of H(L1/2)-H(R1/2) revealed by inelastic neutron scattering are amenable to a square-well and we suppose the same potential holds for D(L1/2)-D(R1/2). In order to explain dielectric and calorimetric measurements of mixed crystals K(3)D((1-ρ))H(ρ)(SO(4))(2) (0 ≤ ρ ≤ 1), we replace the classical notion of order-disorder by the quantum notion of discernible (e.g., D(L1/2)-D(R1/2)) or indiscernible (e.g., H(L1/2)-H(R1/2)) components depending on the separation length of the split wavefunction. The discernible-indiscernible isostructural transition at finite temperatures is induced by a thermal pure quantum state or at 0 K by ρ.

Sulfate-bicarbonate exchange in brush-border membranes from rat renal cortex

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pritchard, J.B.

1987-02-01

Under Na/sup +/-free conditions /sup 35/SO/sub 4//sup 2 -/ uptake by rat renal brush-border membrane (BBM) vesicles could be driven by imposition of a HCO/sup -//sub 3/ gradient (in greater than out). The initial rate of /sup 35/SO/sub 4//sup 2 -/ uptake was stimulated 10-fold, and peak overshoot exceeded equilibrium uptake by 2-3 times. Cl/sup -/, SCN/sup -/, NO/sub 3//sup -/, I/sup -/, and OH/sup -/ were able to substitute for HCO/sub 3//sup -/. Divalent anions, including /sup 35/SO/sub 4//sup 2 -/ itself, were less effective as counterions. HCO/sub 3//sup -/-SO/sub 4//sup 2 -/ exchange was cis-inhibited by disulfonic stilbenes,more » ((SITS)(DIDS)), phloretin, Hg, and S/sub 2/O/sub 3//sup 2 -/. HCO/sub 3//sup -/-driven /sup 35/SO/sub 4//sup 2 -/ uptake was saturable, with an apparent K/sub m/ of 0.4 mM for SO/sub 4//sup 2 -/. Simultaneous imposition of Na/sup +/ and HCO/sub 3//sup -/ gradients produced approximately additive stimulation of /sup 35/SO/sub 4//sup 2 -/ uptake. The HCO/sub 3//sup -/-driven component of /sup 35/SO/sub 4//sup 2 -/ uptake, but not the component driven by Na/sup +/, was inhibited by SITS. Finally, Na/sup +/-driven SO/sub 4//sup 2 -/ accumulation could be reduced by imposing an out greater than in HCO/sub 3//sup +/ gradient, conditions accelerating exchange driven SO/sub 4//sup 2 -/ efflux. These findings indicate the presence of separate Na/sup +/-SO/sub 4//sup 2 -/ cotransport and SO /sub 4//sup 2 -/-anion exchange pathways in the same BBM vesicles.« less

Novel Process of Simultaneous Removal of Nitric Oxide and Sulfur Dioxide Using a Vacuum Ultraviolet (VUV)-Activated O2/H2O/H2O2 System in A Wet VUV-Spraying Reactor.

PubMed

Liu, Yangxian; Wang, Qian; Pan, Jianfeng

2016-12-06

A novel process for NO and SO 2 simultaneous removal using a vacuum ultraviolet (VUV, with 185 nm wavelength)-activated O 2 /H 2 O/H 2 O 2 system in a wet VUV-spraying reactor was developed. The influence of different process variables on NO and SO 2 removal was evaluated. Active species (O 3 and ·OH) and liquid products (SO 3 2- , NO 2 - , SO 4 2- , and NO 3 - ) were analyzed. The chemistry and routes of NO and SO 2 removal were investigated. The oxidation removal system exhibits excellent simultaneous removal capacity for NO and SO 2 , and a maximum removal of 96.8% for NO and complete SO 2 removal were obtained under optimized conditions. SO 2 reaches 100% removal efficiency under most of test conditions. NO removal is obviously affected by several process variables. Increasing VUV power, H 2 O 2 concentration, solution pH, liquid-to-gas ratio, and O 2 concentration greatly enhances NO removal. Increasing NO and SO 2 concentration obviously reduces NO removal. Temperature has a dual impact on NO removal, which has an optimal temperature of 318 K. Sulfuric acid and nitric acid are the main removal products of NO and SO 2 . NO removals by oxidation of O 3 , O·, and ·OH are the primary routes. NO removals by H 2 O 2 oxidation and VUV photolysis are the complementary routes. A potential scaled-up removal process was also proposed initially.

Evaluating behavior of oxygen, nitrate, and sulfate during recharge and quantifying reduction rates in a contaminated aquifer

USGS Publications Warehouse

McGuire, Jennifer T.; Long, David T.; Klug, Michael J.; Haack, Sheridan K.; Hyndman, David W.

2002-01-01

This study evaluates the biogeochemical changes that occur when recharge water comes in contact with a reduced aquifer. It specifically addresses (1) which reactions occur in situ, (2) the order in which these reactions will occur if terminal electron acceptors (TEAs) are introduced simultaneously, (3) the rates of these reactions, and (4) the roles of the aqueous and solid-phase portions of the aquifer. Recharge events of waters containing various combinations of O2, NO3, and SO4 were simulated at a shallow sandy aquifer contaminated with waste fuels and chlorinated solvents using modified push−pull tests to quantify rates. In situ rate constants for aerobic respiration (14.4 day -1), denitrification (5.04−7.44 day-1), and sulfate reduction (4.32−6.48 day-1) were estimated. Results show that when introduced together, NO3 and SO4can be consumed simultaneously at similar rates. To distinguish the role of aqueous phase from that of the solid phase of the aquifer, groundwater was extracted, amended with NO3 and SO4, and monitored over time. Results indicate that neither NO3 nor SO4 was reduced during the course of the aqueous-phase study, suggesting that NO3 and SO4 can behave conservatively in highly reduced water. It is clear that sediments and their associated microbial communities are important in driving redox reactions.

Summer-time distribution of air pollutants in Sequoia National Park, California.

PubMed

Bytnerowicz, Andrzej; Tausz, Michael; Alonso, Rocio; Jones, David; Johnson, Ronald; Grulke, Nancy

2002-01-01

Concentrations of air pollutants were monitored during the May November 1999 period on a network of forested sites in Sequoia National Park, California. Measurements were conducted with: (1) active monitors for nitric oxide (NO), nitrogen dioxide (NO2) and ozone (O3); (2) honeycomb denuder/filter pack systems for nitric acid vapor (HNO3), nitrous acid vapor (HNO2), ammonia (NH3), sulfur dioxide (SO2), particulate nitrate (NO3-), ammonium (NH4+), and sulfate (SO4(2-)); and (3) passive samplers for O3, HNO3 and NO2. Elevated concentrations of O3 (seasonal means 41-71 ppb), HNO3 (seasonal means 0.4-2.9 microg/m3), NH3 (seasonal means 1.6-4.5 microg/m3), NO3 (1.1-2.0 microg/m3) and NH4+ (1.0-1.9 microg/m3) were determined. Concentrations of other pollutants were low. With increasing elevation and distance from the pollution source area of O3, NH3 and HNO3 concentrations decreased. Ammonia and NH4+ were dominant N pollutants indicating strong influence of agricultural emissions on forests and other ecosystems of the Sequoia National Park.

Nitrate transboundary heavy pollution over East Asia in winter

NASA Astrophysics Data System (ADS)

Itahashi, Syuichi; Uno, Itsushi; Osada, Kazuo; Kamiguchi, Yusuke; Yamamoto, Shigekazu; Tamura, Kei; Wang, Zhe; Kurosaki, Yasunori; Kanaya, Yugo

2017-03-01

High PM2. 5 concentrations of around 100 µg m-3 were observed twice during an intensive observation campaign in January 2015 at Fukuoka (33.52° N, 130.47° E) in western Japan. These events were analyzed comprehensively with a regional chemical transport model and synergetic ground-based observations with state-of-the-art measurement systems, which can capture the behavior of secondary inorganic aerosols (SO42-, NO3-, and NH4+). The first episode of high PM2. 5 concentration was dominated by NO3- (type N) and the second episode by SO42- (type S). The concentration of NH4+ (the counterion for SO42- and NO3-) was high for both types. A sensitivity simulation in the chemical transport model showed that the dominant contribution was from transboundary air pollution for both types. To investigate the differences between these types further, the chemical transport model results were examined, and a backward trajectory analysis was used to provide additional information. During both types of episodes, high concentrations of NO3- were found above China, and an air mass that originated from northeast China reached Fukuoka. The travel time from the coastline of China to Fukuoka differed between types: it was 18 h for type N and 24 h for type S. The conversion ratio of SO2 to SO42- (Fs) was less than 0.1 for type N, but reached 0.3 for type S as the air mass approached Fukuoka. The higher Fs for type S was related to the higher relative humidity and the concentration of HO2, which produces H2O2, the most effective oxidant for the aqueous-phase production of SO42-. Analyzing the gas ratio as an indicator of the sensitivity of NO3- to changes in SO42- and NH4+ showed that the air mass over China was NH3-rich for type N, but almost NH3-neutral for type S. Thus, although the high concentration of NO3- above China gradually decreased during transport from China to Fukuoka, higher NO3- concentrations were maintained during transport owing to the lower SO42- for type N. In contrast, for type S, the production of SO42- led to the decomposition of NH4NO3, and more SO42- was transported. Notably, the type N transport pattern was limited to western Japan, especially the island of Kyushu. Transboundary air pollution dominated by SO42- (type S) has been recognized as a major pattern of pollution over East Asia. However, our study confirms the importance of transboundary air pollution dominated by NO3-, which will help refine our understanding of transboundary heavy PM2. 5 pollution in winter over East Asia.

Weekday/weekend differences in ambient aerosol level and chemical characteristics of water-soluble components in the city centre

NASA Astrophysics Data System (ADS)

Khoder, M. I.; Hassan, S. K.

Weekday and weekend ambient aerosol samples were collected from the city centre of Cairo, namely "Ramsis" during the summer season of the year 2006, and have been analyzed for water-soluble ionic species. The average concentrations of the total suspended particulate matter (TSP) and their water-soluble components were higher during weekdays than on weekends, indicating that the decreased traffic density on weekends leads to a decrease in the levels of the TSP and their water-soluble ionic species. The average concentrations of the TSP were 454 μg m -3 on weekdays and 298 μg m -3 on weekends. The weekday/weekend concentration ratios were 1.52 for TSP, 1.27 for SO 42-, 1.64 for Cl -, 1.54 for NO 3-, 1.17 for NH 4+, 1.67 for Ca 2+, 1.83 for Na +, 1.75 for K + and 1.73 for Mg 2+. City centre of Cairo has high levels of the TSP and their water-soluble ionic species compared with many polluted cities in the world. Among all of the measured water-soluble components, SO 42- was the most abundant species followed by Ca 2+ on weekdays and weekends. The average mass ratios of NO 3-/SO 42- in the TSP were 0.41 on weekdays and 0.34 on weekends, suggesting that the stationary source emissions were more predominant. The NH 4+/SO 42- molar ratios and its relation with the concentrations of TSP and Ca 2+ during the weekdays and weekends indicate that the chemical form of sulfate and ammonium in aerosol particles varies with TSP and Ca 2+ levels. At high TSP and Ca 2+ levels, and NH 4+/SO 42- molar ratios less than one, SO 42- in aerosol particles may be present as CaSO 4 and (NH 4) 2SO 4·CaSO 4·2H 2O, whereas it is expected to be present as (NH 4) 2SO 4, (NH 4) 2SO 4·CaSO 4·2H 2O and CaSO 4 at low levels of TSP and Ca 2+, and NH 4+/SO 42- molar ratios between 1 and 2. The mean pH values of the TSP were 7.65 on weekdays and 6.97 on weekends, indicating that aerosol particles brought a large amount of crustal species, and might alleviate the tendency of acidification. The relationships between the concentrations of acidic components (NO 3- and SO 42-) and basic components (NH 4+, Ca 2+ and Mg 2+) on weekdays and weekends indicate that the acidity of aerosol particles is neutralized. Ca 2+ and NH 4+ are the most dominant neutralization substances in Cairo atmosphere.

Effects of air filtration on concentration and deposition of gaseous and particulate air pollutants in open-top field chambers. [Ceanothus crassifolius Torr. , Pinus coulteri D. Don, P. ponderosa Dougl. ex P. C. Lawson

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bytnerowicz, A.; Olszyk, D.M.; Dawson, P.J.

Concentrations of gaseous and particulate air pollutants, and deposition fluxes of NO{sup {minus}}{sub 3}, SO{sup {minus}2}{sub 4}, and NH{sup +}{sub 4} ions to branches of California lilac (Ceanothus crassifolius Torr.), Coulter pine (Pinus coulteri D. Don.), ponderosa pine (P. ponderosa Dougl. ex P. C. Lawson), nylon filters, and paper filters were measured in open-top field chambers with different filtration materials and in chamberless outside plots. Additionally, concentrations of O{sub 3}, NO{sub 2}, NO, SO{sub 2} and total S compounds also were determined in the chambers. Effects of different air filtrations were more evident for deposition fluxes to plant and surrogatemore » surfaces. On the average, in the CHARCOAL chambers, deposition fluxes of NO{sup {minus}}{sub 3}, SO{sup 2{minus}}{sub 4}, and NH{sup +}{sub 4} to the surfaces were reduced to 21, 38, and 26% of the outside values, respectively. In the DUST 1 DUST 2 chambers, deposition fluxes of NO{sup {minus}}{sub 3}, SO{sup 2{minus}}{sub 4}, and NH{sup +}{sub 4} were reduced to about 50, 56, and 75% of the outside levels, respectively. Deposition fluxes of the studied ions to plants were much lower than to nylon and paper filters.« less

Characterization of wet and dry deposition in the downwind of industrial sources in a dry tropical area.

PubMed

Singh, R K; Agrawal, M

2001-12-19

An atmospheric deposition study was conducted in the downwind of Shaktinagar Thermal Power Plant (STPP), Renusagar Thermal Power Plant (RTPP), and Anpara Thermal Power Plant (ATPP), at Singrauli region, Uttar Pradesh (UP), India to characterize dry and wet deposition in relation to different pollution loading. During the study period, dry and wet depositions and levels of gaseous pollutants (SO2 and NO2) were estimated across the sites. Dry deposition was collected on a monthly basis and wet deposition on an event basis. Depositions were analyzed for pH, nitrate (NO3-), ammonium (NH4+), and sulphate (SO4(2-)) contents. Dry deposition rate both collected as clearfall and throughfall varied between 0.15 to 2.28 and 0.33 to 3.48 g m(-2) day(-1), respectively, at control and maximally polluted sites. The pH of dry deposition varied from 5.81 to 6.89 during winter and 6.09 to 7.02 during summer across the sites. During the rainy season, the mean pH of clear wet deposition varied from 6.56 to 7.04 and throughfall varied from 6.81 to 7.22. The concentrations of NO2 and SO2 pollutants were highest during the winter season. Mean SO2 concentrations varied from 18 to 75 g m(-3) at control and differently polluted sites during the winter season. The variation in NO2 concentrations did not show a pattern similar to that of SO2. The highest NO2 concentration during the winter season was 50 g m(-3), observed near RTPP. NO2 concentration did not show much variation among different sites, suggesting that the sources of NO2 emission are evenly distributed along the sites. The concentrations of NH4+, NO3-, and SO4(2-) ions in dry deposition were found to be higher in summer as compared to the winter season. In dry deposition (clearfall) the concentrations of NH4+, NO3-, and SO4(2-) varied from 0.13 to 1.0, 0.81 to 1.95, and 0.82 to 3.27 mg l(-1), respectively, during winter. In wet deposition (clearfall), the above varied from 0.14 to 0.74, 0.81 to 1.82, and 0.67 to 2.70 mg l(-1), respectively. The study clearly showed that both dry and wet depositions varied between the sites and season, suggesting significant impact of industrial activities in modifying the atmospheric input. The nonacidic deposition suggests that there is no threat of acidification of the receiving ecosystem at present.

Fog water chemistry in Shanghai

NASA Astrophysics Data System (ADS)

Li, Pengfei; Li, Xiang; Yang, Chenyu; Wang, Xinjun; Chen, Jianmin; Collett, Jeffrey L., Jr.

2011-08-01

With the aim of understanding the fog chemistry in a Chinese megacity, twenty-six fog water samples were collected in urban Shanghai from March 2009 to March 2010. The following parameters were measured: pH, electrical conductivity (EC), ten inorganic major ions ( SO42-, NO3-, NO2-, F -, Cl -, Na +, K +, Ca 2+, Mg 2+, NH4+) and four major organic acids (CH 3COO -, HCOO -, CO42-, MSA). The total ionic concentration (TIC) and EC of fog samples were one or two orders of magnitude higher than those often found in Europe, North America and other Asian countries. Pollutants were expected to be mainly from local sources, including factories, motor vehicle emissions and civil construction. Non-local sources such as moderate- and long-range transport of sea salt also contributed to pollution levels in fog events as indicated by back trajectory analysis. The pH of the fog water collected during the monitoring period varied from 4.68 to 6.58; acidic fogs represented about 30.8% of the total fog events during this period. The fog water was characterized by high concentrations of SO42- (20.0% of measured TIC), NO3- (17.1%), NH4+ (28.3%) and Ca 2+ (14.4%). SO42- and NO3-, the main precursors of fog acidity, were related to burning fossil fuels and vehicle emissions, respectively. NH4+, originating from the scavenging of gaseous ammonia and particulate ammonium nitrate and ammonium sulfate, and Ca 2+, originating from the scavenging of coarse particles, acted as acid neutralizers and were the main cause for the relatively high pH of fogs in Shanghai. The ratio of ( SO42- + NO3-)/( NH4+ + Ca 2+) was lower than 1, indicating the alkaline nature of the fog water. A high ratio of NO3-/ SO42- and low ratio of HCOO -/CH 3COO - were consistent with large contributions from vehicular emissions that produce severe air pollution in megacities.

Wet chemical techniques for passivation of YBa2Cu3O7(7-x)

NASA Technical Reports Server (NTRS)

Vasquez, R. P.; Foote, M. C.; Hunt, B. D.

1989-01-01

Wet chemical techniques are described for treatment of YBa2Cu3O(7-x) surfaces, resulting in the formation of native compounds with little or no reactivity to water. Promising native compounds include CuI, BaSO4, CuS, Cu2S, and the oxalates, all of which are either insoluble or have very low solubility in water. Treatment with dilute HI results in the formation of a native iodide film which is 80-90 percent CuI with small amounts of YI3 and BaI2. Treatment with dilute H2SO4 results in the formation of a film which is 95 percent BaSO4 and 5 percent Y2(SO4)3. Cu2S is formed on the surface with a dilute Na2S solution. An oxalate film with equal amounts of Y2(C2O4)3 and BaC2O4 results from treatment with dilute oxalic acid. X-ray photoelectron spectra show no significant changes when the sulfide, sulfate, or oxalate films are dipped in water, while the iodide film shows evidence of Cu(OH)2 formation.

Highly time-resolved characterization of water-soluble inorganic ions in PM2.5 in a humid and acidic mega city in Sichuan Basin, China.

PubMed

Tian, Mi; Wang, HuanBo; Chen, Yang; Zhang, LeiMing; Shi, GuangMing; Liu, Yuan; Yu, JiaYan; Zhai, ChongZhi; Wang, Jun; Yang, FuMo

2017-02-15

To investigate the characteristics of water-soluble inorganic ions (WSIIs) in Chongqing, a well-known foggy and acid region in southwestern China, hourly real-time concentrations of five cations (Na + , K + , NH 4 + , Ca 2+ , and Mg 2+ ) and six anions (F - , Cl - , NO 2 - , NO 3 - , PO 4 3- , and SO 4 2- ) in PM 2.5 during winter (from Dec. 18, 2015 to Mar. 20, 2016) in Chongqing were collected by applying In-situ Gas and Aerosol Compositions Monitor. The hourly total concentration of WSIIs was 38.5μg/m 3 on average, accounting for 57% of PM 2.5 mass concentration. Secondary inorganic aerosols (NH 4 + , NO 3 - , and SO 4 2- ) were dominant WSIIs, accounting for 91% of WSIIs mass. Compared to ten years ago, SO 4 2- concentrations were decreased by 31% but NO 3 - levels were doubled, likely indicative of sharply enhanced contribution to fine particle pollution from mobile sources over stationary sources. NO 3 - originated from the current fluxes of NH 3 and HNO 3 onto sulfate particles and/or from in-cloud processes were critical pathways under humid conditions in the study area. Water content and/or RH might be important factors controlling nitrate formation. Trajectory analysis manifested that aerosol pollutions in Chongqing were mostly caused by local emissions. Copyright © 2016 Elsevier B.V. All rights reserved.

Sensitivity analyses of factors influencing CMAQ performance for fine particulate nitrate.

PubMed

Shimadera, Hikari; Hayami, Hiroshi; Chatani, Satoru; Morino, Yu; Mori, Yasuaki; Morikawa, Tazuko; Yamaji, Kazuyo; Ohara, Toshimasa

2014-04-01

Improvement of air quality models is required so that they can be utilized to design effective control strategies for fine particulate matter (PM2.5). The Community Multiscale Air Quality modeling system was applied to the Greater Tokyo Area of Japan in winter 2010 and summer 2011. The model results were compared with observed concentrations of PM2.5 sulfate (SO4(2-)), nitrate (NO3(-)) and ammonium, and gaseous nitric acid (HNO3) and ammonia (NH3). The model approximately reproduced PM2.5 SO4(2-) concentration, but clearly overestimated PM2.5 NO3(-) concentration, which was attributed to overestimation of production of ammonium nitrate (NH4NO3). This study conducted sensitivity analyses of factors associated with the model performance for PM2.5 NO3(-) concentration, including temperature and relative humidity, emission of nitrogen oxides, seasonal variation of NH3 emission, HNO3 and NH3 dry deposition velocities, and heterogeneous reaction probability of dinitrogen pentoxide. Change in NH3 emission directly affected NH3 concentration, and substantially affected NH4NO3 concentration. Higher dry deposition velocities of HNO3 and NH3 led to substantial reductions of concentrations of the gaseous species and NH4NO3. Because uncertainties in NH3 emission and dry deposition processes are probably large, these processes may be key factors for improvement of the model performance for PM2.5 NO3(-). The Community Multiscale Air Quality modeling system clearly overestimated the concentration of fine particulate nitrate in the Greater Tokyo Area of Japan, which was attributed to overestimation of production of ammonium nitrate. Sensitivity analyses were conducted for factors associated with the model performance for nitrate. Ammonia emission and dry deposition of nitric acid and ammonia may be key factors for improvement of the model performance.

Effect of sulphur deprivation on osmotic potential components and nitrogen metabolism in oilseed rape leaves: identification of a new early indicator.

PubMed

Sorin, Elise; Etienne, Philippe; Maillard, Anne; Zamarreño, Angel-Mari; Garcia-Mina, José-Maria; Arkoun, Mustapha; Jamois, Frank; Cruz, Florence; Yvin, Jean-Claude; Ourry, Alain

2015-10-01

Identification of early sulphur (S) deficiency indicators is important for species such as Brassica napus, an S-demanding crop in which yield and the nutritional quality of seeds are negatively affected by S deficiency. Because S is mostly stored as SO4 (2-) in leaf cell vacuoles and can be mobilized during S deficiency, this study investigated the impact of S deprivation on leaf osmotic potential in order to identify compensation processes. Plants were exposed for 28 days to S or to chlorine deprivation in order to differentiate osmotic and metabolic responses. While chlorine deprivation had no significant effects on growth, osmotic potential and nitrogen metabolism, Brassica napus revealed two response periods to S deprivation. The first one occurred during the first 13 days during which plant growth was maintained as a result of vacuolar SO4 (2-) mobilization. In the meantime, leaf osmotic potential of S-deprived plants remained similar to control plants despite a reduction in the SO4 (2-) osmotic contribution, which was fully compensated by an increase in NO3 (-), PO4 (3-) and Cl(-) accumulation. The second response occurred after 13 days of S deprivation with a significant reduction in growth, leaf osmotic potential, NO3 (-) uptake and NO3 (-) reductase activity, whereas amino acids and NO3 (-) were accumulated. This kinetic analysis of S deprivation suggested that a ([Cl(-)]+[NO3 (-)]+[PO4 (3-)]):[SO4 (2-)] ratio could provide a relevant indicator of S deficiency, modified nearly as early as the over-expression of genes encoding SO4 (2-) tonoplastic or plasmalemmal transporters, with the added advantage that it can be easily quantified under field conditions. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Evolution of aerosol chemistry in Xi'an, inland China, during the dust storm period of 2013 - Part 1: Sources, chemical forms and formation mechanisms of nitrate and sulfate

NASA Astrophysics Data System (ADS)

Wang, G. H.; Cheng, C. L.; Huang, Y.; Tao, J.; Ren, Y. Q.; Wu, F.; Meng, J. J.; Li, J. J.; Cheng, Y. T.; Cao, J. J.; Liu, S. X.; Zhang, T.; Zhang, R.; Chen, Y. B.

2014-11-01

A total suspended particulate (TSP) sample was collected hourly in Xi'an, an inland megacity of China near the Loess Plateau, during a dust storm event of 2013 (9 March 18:00-12 March 10:00 LT), along with a size-resolved aerosol sampling and an online measurement of PM2.5. The TSP and size-resolved samples were determined for elemental carbon (EC), organic carbon (OC), water-soluble organic carbon (WSOC) and nitrogen (WSON), inorganic ions and elements to investigate chemistry evolution of dust particles. Hourly concentrations of Cl-, NO3-, SO42-, Na+ and Ca2+ in the TSP samples reached up to 34, 12, 180, 72 and 28 μg m-3, respectively, when dust peak arrived over Xi'an. Chemical compositions of the TSP samples showed that during the whole observation period NH4+ and NO3- were linearly correlated with each other (r2=0.76) with a molar ratio of 1 : 1, while SO42- and Cl- were well correlated with Na+, Ca2+, Mg2+ and K+ (r2 > 0.85). Size distributions of NH4+ and NO3- presented a same pattern, which dominated in the coarse mode (> 2.1 μm) during the event and predominated in the fine mode (< 2.1 μm) during the non-event. SO42- and Cl- also dominated in the coarse mode during the event hours, but both exhibited two equivalent peaks in both the fine and the coarse modes during the non-event, due to the fine-mode accumulations of secondarily produced SO42- and biomass-burning-emitted Cl- and the coarse-mode enrichments of urban soil-derived SO42- and Cl-. Linear fit regression analysis further indicated that SO42- and Cl- in the dust samples possibly exist as Na2SO4, CaSO4 and NaCl, which directly originated from Gobi desert surface soil, while NH4+ and NO3- in the dust samples exist as NH4NO3. We propose a mechanism to explain these observations in which aqueous phase of dust particle surface is formed via uptake of water vapor by hygroscopic salts such as Na2SO4 and NaCl, followed by heterogeneous formation of nitrate on the liquid phase and subsequent absorption of ammonia. Our data indicate that 54 ± 20% and 60 ± 23% of NH4+ and NO3- during the dust period were secondarily produced via this pathway, with the remaining derived from the Gobi desert and Loess Plateau, while SO42- in the event almost entirely originated from the desert regions. Such cases are different from those in the East Asian continental outflow region, where during Asia dust storm events SO42- is secondarily produced and concentrates in sub-micrometer particles as (NH4)2SO4 and/or NH4HSO4. To the best of our knowledge, the current work for the first time revealed an infant state of the East Asian dust ageing process in the regions near the source, which is helpful for researchers to understand the panorama of East Asian dust ageing process from the desert area to the downwind region.

Effect of Sodium Sulfate, Ammonium Chloride, Ammonium Nitrate, and Salt Mixtures on Aqueous Phase Partitioning of Organic Compounds.

PubMed

Wang, Chen; Lei, Ying Duan; Wania, Frank

2016-12-06

Dissolved inorganic salts influence the partitioning of organic compounds into the aqueous phase. This influence is especially significant in atmospheric aerosol, which usually contains large amounts of ions, including sodium, ammonium, chloride, sulfate, and nitrate. However, empirical data on this salt effect are very sparse. Here, the partitioning of numerous organic compounds into solutions of Na 2 SO 4 , NH 4 Cl, and NH 4 NO 3 was measured and compared with existing data for NaCl and (NH 4 ) 2 SO 4 . Salt mixtures were also tested to establish whether the salt effect is additive. In general, the salt effect showed a decreasing trend of Na 2 SO 4 > (NH) 2 SO 4 > NaCl > NH 4 Cl > NH 4 NO 3 for the studied organic compounds, implying the following relative strength of the salt effect of individual anions: SO 4 2- > Cl - > NO 3 - and of cations: Na + > NH 4 + . The salt effect of different salts is moderately correlated. Predictive models for the salt effect were developed based on the experimental data. The experimental data indicate that the salt effect of mixtures may not be entirely additive. However, the deviation from additivity, if it exists, is small. Data of very high quality are required to establish whether the effect of constituent ions or salts is additive or not.

Investigation of efflorescence of inorganic aerosols using fluorescence spectroscopy.

PubMed

Choi, Man Yee; Chan, Chak K

2005-02-17

The phase transition is one of the most fundamental phenomena affecting the physical and chemical properties of atmospheric aerosols. Efflorescence, in particular, is not well understood, partly because the molecular interactions between the solute and water molecules of saturated or supersaturated solution droplets have not been well characterized. Recently, we developed a technique that combines the use of an electrodynamic balance and a fluorescence dye, 8-hydroxyl-1,3,6-pyrenetrisulfonate (pyranine), to study the distributions of solvated and free water in aqueous droplets (Choi, M. Y.; Chan, C. K.; Zhang, Y. H. J. Phys. Chem. A 2004, 108, 1133). We found that the equality of the amounts of solvated and free water is a necessary but not sufficient condition for efflorescence. For efflorescing compounds such as Na2SO4, (NH4)2SO4, and a mixture of NaCl and Na2SO4, the amount of free water decreases, while that of solvated water is roughly constant in bulk measurements and decreases less dramatically than that of free water in single-particle measurements as the relative humidity (RH) decreases. Efflorescence of the supersaturated droplets of these solutions occurs when the amounts of free and solvated water are equal, which is consistent with our previous observation for NaCl. For nonefflorescing compounds in single-particle levitation experiments such as MgSO4 and Mg(NO3)2, the amounts of free and solvated water are equal at a water-to-solute molar ratio of about 6, at which spectral changes due to the formation of contact ion pairs between magnesium and the anions occur as shown by Raman spectroscopy. Fluorescence imaging shows that the droplets of diluted Mg(NO3)2 (at 80% RH) and MgSO4 are homogeneous but those of NaCl, Na2SO4, (NH4)2SO4, and supersaturated Mg(NO3)2 (at 10% RH) are heterogeneous in terms of the solvated-to-free water distribution. The solvated-to-free water ratios in NaCl, Na2SO4, and (NH4)2SO4 droplets are higher in the outer regions by about half a radius deep than at the center of the droplets.

Inorganic ions in ambient fine particles over a National Park in central India: Seasonality, dependencies between SO42-, NO3-, and NH4+, and neutralization of aerosol acidity

NASA Astrophysics Data System (ADS)

Kumar, Samresh; Sunder Raman, Ramya

2016-10-01

Twelve hour integrated ambient fine particles (PM2.5) were collected over an Van Vihar National Park (VVNP), in Bhopal, Central India. Samples were collected on filter substrates every-other-day for two years (2012 and 2013). In addition to PM2.5 mass concentration, water soluble inorganic ions (WSIIs) were also measured. Further, on-site meteorological parameters including temperature, wind speed, wind direction, relative humidity, rainfall and atmospheric pressure were recorded. During 2012, the average PM2.5 concentration was 40 ± 31 μgm-3 while during 2013 it was 48 ± 50 μgm-3. Further, in about 20% of the samples the 12 h integrated fine PM mass exceeded the daily (24 h) average standards (60 μgm-3). This observation suggests that the PM2.5 mass concentration at the study site is likely to be in violation of the National Ambient Air Quality Standard (NAAQS), India. During the study period the sum of three major ions (SO42-, NO3-, and NH4+) accounted for 19.4% of PM2.5 mass on average. Air parcel back trajectory ensembles revealed that emissions from thermal power plants were likely to be the main regional source of particulate SO42- and NO3- measured over VVNP. Further, local traffic activities appeared to have no significant impact on the concentrations of PM2.5 and its WSIIs constituents, as revealed by a day-of-the-week analysis. PM2.5 mass, SO42-, NO3-, and NH4+ showed a pronounced seasonal trend with winter (Jan, Feb) and post-monsoon (Oct, Nov, Dec) highs and pre-monsoon (Mar, Apr, May) and monsoon (Jun, Jul, Aug, Sep) lows, during both 2012 and 2013. Further, when the sum of SO42- and NO3- constituted greater than 90% of water soluble inorganic anions by mass, they were linearly dependent on one another and moderately anti-correlated (r2 = 0.60). The molar ratios of NH4+ and non-sea salt SO42- were examined to understand the aerosol neutralization mechanisms and particulate NO3- formation. An assessment of these ratios and subsequent analyses suggested that in NH4+ rich samples, NO3- and non-sea salt SO42- were almost entirely neutralized by NH4+. In NH4+ poor samples, in addition to NH4+ non-sea salt K+ played a role in acidity neutralization. These observations are unlike those reported for PM10 and total suspended particles (TSP) over other locations in India, where mineral aerosol species (specifically Ca2+) played an important role in neutralizing acidic species. Additionally, both during 2012 and 2013, the aerosol acidity showed a pronounced seasonality - the aerosol was alkaline or near-neutral during the winter and post-monsoon seasons, while during the pre-monsoon and monsoon seasons it was acidic.

Phytoextraction of Cadmium and Zinc By Sedum plumbizincicola Using Different Nitrogen Fertilizers, a Nitrification Inhibitor and a Urease Inhibitor.

PubMed

Arnamwong, Suteera; Wu, Longhua; Hu, Pengjie; Yuan, Cheng; Thiravetyan, Paitip; Luo, Yongming; Christie, Peter

2015-01-01

Cadmium (Cd) and zinc (Zn) phytoavailability and their phytoextraction by Sedum plumbizincicola using different nitrogen fertilizers, nitrification inhibitor (dicyandiamide, DCD) and urease inhibitor (N-(n-Butyl) thiophosphoric triamide, NBPT) were investigated in pot experiments where the soil was contaminated with 0.99 mg kg(-1) of Cd and 241 mg kg(-1) Zn. The soil solution pH varied between 7.30 and 8.25 during plant growth which was little affected by the type of N fertilizer. The (NH4)2SO4+DCD treatment produced higher NH4+-N concentrations in soil solution than the (NH4)2SO4 and NaNO3 treatment which indicated that DCD addition inhibited the nitrification process. Shoot Cd and Zn concentrations across all treatments showed ranges of 52.9-88.3 and 2691-4276 mg kg(-1), respectively. The (NH4)2SO4+DCD treatment produced slightly higher but not significant Cd and Zn concentrations in the xylem sap than the NaNO3 treatment. Plant shoots grown with NaNO3 had higher Cd concentrations than (NH4)2SO4+DCD treatment at 24.0 and 15.4 mg kg(-1), respectively. N fertilizer application had no significant effect on shoot dry biomass. Total Cd uptake in the urea+DCD treatment was higher than in the control, urea+NBPT, urea+NBPT+DCD, or urea treatments, by about 17.5, 23.3, 10.7, and 25.1%, respectively.

The indoor-outdoor characteristics of water-soluble ion in PM2.5 in Tianjin wintertime.

PubMed

Wang, Baoqing; Niu, Honghong; Liu, Bowei; Hu, Xinxin; Ren, Zihui

2018-05-15

The indoor and outdoor PM 2.5 mass concentration, water-soluble ion by filter sampler was analyzed on December 3-21, 2015 during wintertime in Tianjin, China. The results indicate that high humidity conditions result in the accumulation of atmospheric pollutants and reduce atmosphere visibility. The I/O ratio for PM 2.5 concentration in dormitory and lab are less than 1 in haze days. Indoor PM 2.5 concentration increases rapidly with outdoor PM 2.5 concentration increasing in haze days. The filtration factors of the dormitory and lab indicate nearly half of the outdoor PM 2.5 enters indoor environment. The human activities in dormitory could cause more the formation of PM 2.5 than those in lab. The concentration of SO 4 2- is the highest ion in water-soluble ion for outdoor PM 2.5 . The SO 4 2- , NO 3 - , NH 4 + , and Cl - are generated mainly by outdoor sources; however, the Na + , Ca 2+ , and Mg 2+ are generated mainly by indoor sources. The NH 4 NO 3 , (NH 4 ) 2 SO 4 , and NH 4 Cl accounts for 20.2~41.8%, 32.0~51.4%, and 6.4~10.6% of the total water-soluble ion in different indoor-outdoor environment. The total secondary aerosols including NH 4 NO 3 , (NH 4 ) 2 SO 4 , and NH 4 Cl in PM 2.5 are 28.3, 42.1, 28.2, 31.0, and 33.9% in outdoor environment for haze days, outdoor environment for non-haze days, dormitory for haze days, dormitory for non-haze days, and lab for haze days, respectively.

[Characteristics of mass size distributions of water-soluble, inorganic ions during summer and winter haze days of Beijing].

PubMed

Huang, Yi-Min; Liu, Zi-Rui; Chen, Hong; Wang, Yue-Si

2013-04-01

To investigate the size distribution characteristics of water soluble inorganic ions in haze days, the particle samples were collected by two Andersen cascade impactors in Beijing during summer and winter time and each sampling period lasted two weeks. Online measurement of PM10 and PM2.5 using TEOM were also conducted at the same time. Sources and formation mechanism of water soluble inorganic ions were analyzed based on their size distributions. The results showed that average concentrations of PM10 and PM 2.5 were (245.5 +/- 8.4) microg x m(-3) and (120.2 +/- 2.0) microg x m(-3) during summer haze days (SHD), and were (384.2 +/- 30.2) microg x m(-3) and (252.7 +/- 47.1) microg x m(-3) during winter haze days (WHD), which suggested fine particles predominated haze pollution episode in both seasons. Total water-soluble inorganic ions concentrations were higher in haze days than those in non-haze days, especially in fine particles. Furthermore, concentrations of secondary inorganic ions (SO4(2-), NO3(-) and NH4(+)) increased quicker than other inorganic ions in fine particles during haze days, indicating secondary inorganic ions played an important role in the formation of haze pollution. Similar size distributions were found for all Sinorganic water soluble ions except for NO3(-), during SHD and WHD. SO4(2-) and NH4(+) dominated in the fine mode (PM1.0) while Mg2+ and Ca2+ accumulated in coarse fraction, Na+, Cl- and K+ showed a bimodal distribution. For NO3(-), however, it showed a bimodal distribution during SHD and a unimodal distribution dominated in the fine fraction was found during WHD. The average mass median aerodynamic diameter (MMAD) of SO4(2-) was 0.64 microm in SHD, which suggested the formation of SO4(2-) was mainly attributed to in-cloud processes. Furthermore, a higher apparent conversion rate of sulfur dioxide (SOR) was found in SHD, indicating more fine particles were produced by photochemical reaction in haze days than that in non-haze days. The MMAD of SO4(2-) increased to 0.89 microm in WHD, local emission of SO2 and the subsequently heterogeneous reaction became the main source of SO4(2-) during winter time. The average MMADs of NO3(-) were 2.85 microm and 0.80 microm in SHD and WHD, respectively. Influenced by the seasonal temperature difference, NO3(-) mainly existed in the form of calcium nitrate in coarse mode during SHD while the fine mode nitrate was associated with ammonium during WHD.

Atmospheric dry deposition in the vicinity of the Salton Sea, California - I: Air pollution and deposition in a desert environment

USGS Publications Warehouse

Alonso, R.; Bytnerowicz, A.; Boarman, W.I.

2005-01-01

Air pollutant concentrations and atmospheric dry deposition were monitored seasonally at the Salton Sea, southern California. Measurements of ozone (O 3), nitric acid vapor (HNO3), ammonia (NH3), nitric oxide (NO), nitrogen dioxide (NO2) and sulfur dioxide (SO 2) were performed using passive samplers. Deposition rates of NO 3-, NH4+, Cl-, SO 42-, Na+, K+ and Ca2+ to creosote bush branches and nylon filters as surrogate surfaces were determined for one-week long exposure periods. Maximum O3 values were recorded in spring with 24-h average values of 108.8 ??g m-3. Concentrations of NO and NO2 were low and within ranges of the non-urban areas in California (0.4-5.6 and 3.3-16.2 ??g m-3 ranges, respectively). Concentrations of HNO3 (2.0-6.7 ??g m-3) and NH 3 (6.4-15.7 ??g m-3) were elevated and above the levels typical for remote locations in California. Deposition rates of Cl-, SO42-, Na+, K+ and Ca2+ were related to the influence of sea spray or to suspended soil particles, and no strong enrichments caused by ions originated by human activities were detected. Dry deposition rates of NO3- and NH4+ were similar to values registered in areas where symptoms of nitrogen saturation and changes in species composition have been described. Deposition of nitrogenous compounds might be contributing to eutrophication processes at the Salton Sea. ?? 2005 Elsevier Ltd. All rights reserved.

Effects of inorganic electrolyte anions on enrichment of Cu(II) ions with aminated Fe3O4/graphene oxide: Cu(II) speciation prediction and surface charge measurement.

PubMed

Hu, Xin-jiang; Liu, Yun-guo; Zeng, Guang-ming; Wang, Hui; You, Shao-hong; Hu, Xi; Tan, Xiao-fei; Chen, An-wei; Guo, Fang-ying

2015-05-01

The present work evaluated the effects of six inorganic electrolyte anions on Cu(II) removal using aminated Fe3O4/graphene oxide (AMGO) in single- and multi-ion systems. A 2(6-2) fractional factorial design (FFD) was employed for assessing the effects of multiple anions on the adsorption process. The results indicated that the Cu(II) adsorption was strongly dependent on pH and could be significantly affected by inorganic electrolyte anions due to the changes in Cu(II) speciation and surface charge of AMGO. In the single-ion systems, the presence of monovalent anions (Cl(-), ClO4(-), and NO3(-)) slightly increased the Cu(II) adsorption onto AMGO at low pH, while the Cu(II) adsorption was largely enhanced by the presence of SO4(2-), CO3(2-), and HPO4(2-). Based on the estimates of major effects and interactions from FFD, the factorial effects of the six selected species on Cu(II) adsorption in multi-ion system were in the following sequence: HPO4(2-)>CO3(2-)>Cl(-)>SO4(2-)>NO3(-)=ClO4(-), and the combined factors of AD (Cl(-)×SO4(2-)) and EF (Cl(-)×SO4(2-)) had significant effects on Cu(II) removal. Copyright © 2015 Elsevier Ltd. All rights reserved.

[Size distributions and source apportionment of soluble ions in aerosol in Nanjing].

PubMed

Xue, Guo-Qiang; Zhu, Bin; Wang, Hong-Lei

2014-05-01

To explore the seasonal variation and source apportionment of soluble ions in PM10, PM2.1 and PM1.1, the aerosol mass. concentration and soluble ion concentration were investigated during a one-year observation in the urban-district and north suburb. As the results showed, (1)The concentrations of PM10, PM2.1, PM1.1 were in the order of winter > spring > autumn > summer. In spring, summer and autumn, the concentrations of PM10, PM2.1, PM1.1 in the north suburb were higher than in the urban, while the situation, was opposite in winter. (2) SO(2-)(4), NO(-)(3), Ca2+, NH(+)(4), Cl-, K+, Na+, F-, NO;, Mg2+ were measured, and their total concentration in PM10 was 46 microg.m -3 in urban sites and 39.6 microg m in north suburbs. Mass fraction percentage o f water soluble ion in PM2.1-10, PM1 1-2.1, PM1.1 in the urban district increased from 20.4% to 49.5% and 56% , and the value in the north suburb increased from 18.3% to 37. 9% and 42.5%. (3) Major ions, SO(2-)(4), NO(-)(3) , NH(+)(4) , second components and Ca2+ , had significant seasonal variation. In the urban district, the highest concentrations were observed in winter, and the lowest in summer, while in the. north suburb, the highest concentrations were observed in spring, and the lowest in summer. The seasonal changing climate in Nanjing and different anthropogenic influences with land surface in urban-suburb may be the major factors for the ions' seasonal variation. (4) NH(+)(4) , SO(2-)(4) , NO(-)(3) came from secondary chemical reactions of NH3, SO2, NO,, and these precursors mostly came from automobile exhaust in Summer while equally came from automobile exhaust and fossil fuel in winter. Cl- came from biomass burning in Winter . while transported from sea salt with Na+ in Summer. Ca2+ and Mg2+ came from ground dust and construction dust. K+, F- , NO(-)(2) may come from biomass burning and industrial emissions.

Atmospheric dry deposition on pines in the Eastern Brook Lake Watershed, Sierra Nevada, California

NASA Astrophysics Data System (ADS)

Bytnerowicz, Andrzej; Dawson, P. J.; Morrison, C. L.; Poe, M. P.

Atmospheric dry deposition to branches of Pinus contorta and P. albicaulis was measured during summer 1987 in a sub-alpine zone at Eastern Brook Lake Watershed (EBLW), eastern Sierra Nevada, California. Results are presented as deposition fluxes of NO 3-, SO 42-, PO 43-, Cl -, F -, NH 4+, Ca 2+, Mg 2+, Na +, K +, Zn 2+, Fe 3+, Mn 2+, Pb 2+ and H +, and compared with other locations in California and elsewhere. Deposition fluxes of anions and cations to the pine branches were low, several times lower than the values determined near the Emerald Lake Watershed (ELW), another sub-alpine location in the western Sierra Nevada. The sums of deposition fluxes of the measured cations and anions to pine surfaces were similar, in contrast to the ELW location where the sums of cation fluxes were much higher than the sums of anion fluxes. A strong positive correlation between depositions of NO 3- and NH 4+, as well as SO 42- and Ca 2+, suggested that large portions of these ions might have originated from particulate NH 4NO 3 and CaSO 4 deposited on pine surfaces. An estimated total N dry deposition (surface deposition of NO 3- and NH 4+ and internal uptake of NO 2 and HNO 3) to the forested area of the EBLW was 29.54 eq ha -1 yr - (about 414 g H ha -1 yr -1).

Sodium intercalation in the phosphosulfate cathode NaFe2(PO4)(SO4)2

NASA Astrophysics Data System (ADS)

Ben Yahia, Hamdi; Essehli, Rachid; Amin, Ruhul; Boulahya, Khalid; Okumura, Toyoki; Belharouak, Ilias

2018-04-01

The compound NaFe2(PO4)(SO4)2 is successfully synthesized via a solid state reaction route and its crystal structure is determined using powder X-ray diffraction data. NaFe2(PO4)(SO4)2 phase is also characterized by cyclic voltammetry, galvanostatic cycling and electrochemical impedance spectroscopy. NaFe2(PO4)(SO4)2 crystallizes with the well-known NASICON-type structure. SAED and HRTEM experiments confirm the structural model, and no ordering between the PO4-3 and SO4-2 polyanions is detected. The electrochemical tests indicate that NaFe2(PO4)(SO4)2 is a 3 V sodium intercalating cathode. The electrical conductivity is relatively low (2.2 × 10-6 Scm-1 at 200 °C) and the obtained activation energy is ∼0.60eV. The GITT experiments indicate that the diffusivity values are in the range of 10-11-10-12 cm2/s within the measured sodium concentrations.

The comparison of structure and anticancer activity in vitro of polysaccharides from brown algae Alaria marginata and A. angusta.

PubMed

Usoltseva Menshova, Roza V; Anastyuk, Stanislav D; Shevchenko, Natalia M; Zvyagintseva, Tatiana N; Ermakova, Svetlana P

2016-11-20

Laminaran and three fucoidan fractions were obtained from the brown alga Alaria marginata. Alaria angusta, studied earlier by us, has the same polysaccharide composition. Galactofucan AmF3 from A. marginata has a main chain of →3)-α-l-Fucp-(2,4-SO3(-))-(1→residues, similar to galactofucan from A. angusta. However, the structure of the branches in fucoidan AmF3 can differ from those in the fucoidan from A. angusta. The following fragments were identified in AmF3: HexA-(1→2)-Fuc, HexA-(1→2)-Gal, Gal-(1→4)-HexA, Fuc-(1→2)-Gal-6-SO3(-), Fuc-4-SO3(-)-(1→6)-Gal, Gal-(1→2)-Gal-2-SO3(-), Gal-4-SO3(-)-(1 →6)-Gal, Gal-4-SO3(-)-(1→3)-Fuc-(1→3)-Fuc, Fuc-4-SO3(-)-(1→6)-Gal-(1→4)-Gal, Gal-(1→4)-Gal-(1→3)-Fuc, Gal-2-SO3(-)-(1→4)-Gal-(1→4)-Gal, Gal-(1→4)-Gal-6-SO3(-)-(1→2)-Gal. Chains of galactose residues (DP up to 9) were found in AmF3 fucoidan. The laminarans, galactofucans and their derivatives from both algae exhibited no cytotoxicity in vitro. Polysaccharides from A. angusta were more effective against colony formation of HT-29 cells, while those from A. marginata had a greater effect on T-47D cells. Sulfated and desulfated fucoidans possessed weak antitumor activity using SK-MEL-28 cells. Copyright © 2016 Elsevier Ltd. All rights reserved.

Densities and apparent molar volumes of atmospherically important electrolyte solutions. 1. The solutes H2SO4, HNO3, HCl, Na2SO4, NaNO3, NaCl, (NH4)2SO4, NH4NO3, and NH4Cl from 0 to 50 °C, including extrapolations to very low temperature and to the pure liquid state, and NaHSO4, NaOH, and NH3 at 25 °C.

PubMed

Clegg, S L; Wexler, A S

2011-04-21

Calculations of the size and density of atmospheric aerosols are complicated by the fact that they can exist at concentrations highly supersaturated with respect to dissolved salts and supercooled with respect to ice. Densities and apparent molar volumes of solutes in aqueous solutions containing the solutes H(2)SO(4), HNO(3), HCl, Na(2)SO(4), NaNO(3), NaCl, (NH(4))(2)SO(4), NH(4)NO(3), and NH(4)Cl have been critically evaluated and represented using fitted equations from 0 to 50 °C or greater and from infinite dilution to concentrations saturated or supersaturated with respect to the dissolved salts. Using extrapolated densities of high-temperature solutions and melts, the relationship between density and concentration is extended to the hypothetical pure liquid solutes. Above a given reference concentration of a few mol kg(-1), it is observed that density increases almost linearly with decreasing temperature, and comparisons with available data below 0 °C suggest that the fitted equations for density can be extrapolated to very low temperatures. As concentration is decreased below the reference concentration, the variation of density with temperature tends to that of water (which decreases as temperature is reduced below 3.98 °C). In this region below the reference concentration, and below 0 °C, densities are calculated using extrapolated apparent molar volumes which are constrained to agree at the reference concentrations with an equation for the directly fitted density. Calculated volume properties agree well with available data at low temperatures, for both concentrated and dilute solutions. Comparisons are made with literature data for temperatures of maximum density. Apparent molar volumes at infinite dilution are consistent, on a single ion basis, to better than ±0.1 cm(3) mol(-1) from 0 to 50 °C. Volume properties of aqueous NaHSO(4), NaOH, and NH(3) have also been evaluated, at 25 °C only. In part 2 of this work (ref 1 ) an ion interaction (Pitzer) model has been used to calculate apparent molar volumes of H(2)SO(4) in 0-3 mol kg(-1) aqueous solutions of the pure acid and to represent directly the effect of the HSO(4)(-) ↔ H(+) + SO(4)(2-) reaction. The results are incorporated into the treatment of aqueous H(2)SO(4) density described here. Densities and apparent molar volumes from -20 to 50 °C, and from 0 to 100 wt % of solute, are tabulated for the electrolytes listed in the title and have also been incorporated into the extended aerosol inorganics model (E-AIM, http://www.aim.env.uea.ac.uk/aim/aim.php) together with densities of the solid salts and hydrates.

An intercomparison of airborne nitrogen dioxide instruments

NASA Technical Reports Server (NTRS)

Gregory, G. L.; Hoell, J. M., Jr.; Carroll, M. A.; Ridley, B. A.; Davis, D. D.; Bradshaw, J.; Rodgers, M. O.; Sandholm, S. T.; Schiff, H. I.; Torres, A. L.

1990-01-01

Results on NO2 instruments are reported from the NASA Global Tropospheric Experiment Chemical Instrumentation Test and Evaluation 2 (CITE 2) program in summer 1986. The instruments tested were (1) a two-photon LIF system using a laser for NO2-NO photolysis, (2) a chemiluminescence (CL) detector using FeSO4 for NO2-NO conversion, (3) a CL detector using an arc lamp for NO2-NO photolysis, and (4) a tunable-laser-diode multipath-absorption system. The procedures for the CITE 2 ground-based and flight tests are described in detail, and the results are presented in extensive graphs. Instrument (2) was eliminated because the FeSO4 converted atmospheric PAN to NO, resulting in spuriously high NO2 values. The remaining instruments gave readings in 30-40-percent agreement at NO2 mixing ratios of 100-200 parts per trillion by volume (pptv). At ratios below 50 pptv, the correlation among the measurements was very poor, with a tendency for system (4) to give higher values than (1) or (3).

Superparamagnetic Fe3O4 particles formed by oxidation of pyrite heated in an anoxic atmosphere

USGS Publications Warehouse

Thorpe, A.N.; Senftle, F.E.; Talley, R.; Hetherington, S.; Dulong, F.

1990-01-01

As a follow-up to previous gas analysis experiments in which pyrite was heated to 681 K in an anoxic (oxygen starved) atmosphere, the first oxidation product, FeSO4, was studied as a bulk material. No decomposition of FeSO4 to Fe3O4 was observed in the temperature range studied. The lack of decomposition of bulk FeSO4 to Fe3O4 suggests that FeS2 oxidizes directly to Fe3O4, or that FeSO4, FeS2 and O2 react together to form Fe3O4. Magnetic susceptibility and magnetization measurements, along with magnetic hysteresis curves, show that small particles of Fe3O4 form on the pyrite surface, rather than a continuous layer of bulk Fe3O4. A working model describing the oxidation steps is presented. ?? 1990.

Health risk of inhalation exposure to sub-10 µm particulate matter and gaseous pollutants in an urban-industrial area in South Africa: an ecological study

PubMed Central

Morakinyo, Oyewale Mayowa; Adebowale, Ayo Stephen; Mokgobu, Matlou Ingrid; Mukhola, Murembiwa Stanley

2017-01-01

Objective To assess the health risks associated with exposure to particulate matter (PM10), sulphur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO) and ozone (O3). Design The study is an ecological study that used the year 2014 hourly ambient pollution data. Setting The study was conducted in an industrial area located in Pretoria West, South Africa. The area accommodates a coal-fired power station, metallurgical industries such as a coke plant and a manganese smelter. Data and method Estimate of possible health risks from exposure to airborne PM10, SO2, NO2, CO and O3 was performed using the US Environmental Protection Agency human health risk assessment framework. A scenario-assessment approach where normal (average exposure) and worst-case (continuous exposure) scenarios were developed for intermediate (24-hour) and chronic (annual) exposure periods for different exposure groups (infants, children, adults). The normal acute (1-hour) exposure to these pollutants was also determined. Outcome measures Presence or absence of adverse health effects from exposure to airborne pollutants. Results Average annual ambient concentration of PM10, NO2 and SO2 recorded was 48.3±43.4, 11.50±11.6 and 18.68±25.4 µg/m3, respectively, whereas the South African National Ambient Air Quality recommended 40, 40 and 50 µg/m3 for PM10, NO2 and SO2, respectively. Exposure to an hour's concentration of NO2, SO2, CO and O3, an 8-hour concentration of CO and O3, and a 24-hour concentration of PM10, NO2 and SO2 will not likely produce adverse effects to sensitive exposed groups. However, infants and children, rather than adults, are more likely to be affected. Moreover, for chronic annual exposure, PM10, NO2 and SO2 posed a health risk to sensitive individuals, with the severity of risk varying across exposed groups. Conclusions Long-term chronic exposure to airborne PM10, NO2 and SO2 pollutants may result in health risks among the study population. PMID:28289048

X-ray investigation of molten crystal hydrates H2SO4(nH2O) and HNO3(nH2O)

NASA Technical Reports Server (NTRS)

Romanova, A. V.; Skryshevskiy, A. F.

1979-01-01

Integral analysis of the intensity of the electron density distribution curve in molten crystal hydrates provided by X-ray analysis, permits the following conclusions on the structure of the complex SO and NO ions, and the short-range order in the structure of the solution. The SO4 ion in the solution has a tetrahedral structure with an S to O distance equal to 1.5 A. For the NO3 in the solution, a planar triangular shape is probable, with an N to O distance equal to 1.2 A. Preferential distances between each of the oxygens of the SO ion and the nearest molecules of water proved near to the corresponding distances in solid crystal hydrates. For an (H2SO4)(H2O) solution, the average number of water molecules surrounding each oxygen atom of the SO4 (--) ion was on the order of 1.3 molecules. Hence the preferential distances between the water molecules and the oxygen atoms of the SO ion, and the preference of their mutual position, correspond to the fixed position of these same elements of the structure in the solid crystal hydrate.

Ionic composition of lower tropospheric aerosols at a Northeastern Mediterranean site: implications regarding sources and long-range transport

NASA Astrophysics Data System (ADS)

Koçak, Mustafa; Kubilay, Nilgün; Mihalopoulos, Nikos

Daily bulk aerosol filter samples were collected at Erdemli (36.6°N, 34.3°E) on the Mediterranean coast of Turkey for a 4-year period between 1996 and 1999. Concentrations of the water-soluble ions (Cl -, Br -, NO 3-, SO 42-, C 2O 42-, MSA -, Na +; NH 4+, K +, Mg 2+ and Ca 2+) were measured in a total of 610 samples. In addition, three-dimensional (3-D), 3-day back trajectories of air masses arriving daily at Erdemli were calculated to determine potential aerosol source regions. The results indicated that the seasonal variability of atmospheric concentrations for ionic species at Erdemli were related to precipitation events. The atmospheric concentration of measured species (except those of a marine origin) decreased to minimum values during winter, whereas, during dry summer months the lack of precipitation resulted in their accumulation in the atmosphere. During the transition periods, although there was still precipitation, crustal ions (mainly nss-Ca 2+ and in lesser extent nss-K + and nss-Mg 2+) exhibited sporadic but intense concentration peaks due to the intrusion of dust from the Sahara and the Arabian Peninsula. The results obtained from factor analysis and inter-species correlation suggested the presence of three main sources influencing concentrations: crustal, marine and anthropogenic sources. Multiple regression analysis indicated that the main non-sea-salt ions were associated with the formation of NH 4HSO 4, (NH 4) 2SO 4, Ca(NO 3) 2, CaSO 4 and CaCO 3. Formation of NH 4NO 3 and partial neutralization of H 2SO 4 by NH 4+ and Ca 2+ was found to occur mainly in summer.

Chemical Composition of Atmospheric Aerosols From High and Low Altitude Sites in Northern and Western India

NASA Astrophysics Data System (ADS)

Rastogi, N.; Athiyarath, S.; Sarin, M.; R, R.

2006-12-01

The chemical composition of ambient aerosols, collected during wintertime from four designated sites: Ahmedabad (23.0oN, 72.6oE, 49 m asl), Mt Abu (24.6oN, 72.7oE, 1680 m asl), Hisar (29.2oN, 75.7oE, 216m asl) and Nainital (29.4oN, 79.5oE, 1940 m asl), has been studied to understand the potential role of regional emission sources as well as the long-range transport of chemical constituents through free troposphere. The two high altitude sites, Mt Abu and Nainital, exhibit free tropospheric characteristics during wintertime; whereas the urban sites (Ahmedabad and Hisar) are within boundary layer. The ratios of major ionic species, measured in water extracts of aerosols, are considered to be advantageous in order to remove the effect of aerosol mass loading on the atmospheric concentrations of species at different sites. At low-altitude-urban sites (Ahmedabad and Hisar), geometric mean of Ca2+/Na+ ratios (4.3 and 4.5) and HCO3-/ Ca2+ ratios (1.7 and 1.5) are comparable; whereas significant differences are observed in Cl-/Na+ (1.1 and 0.6), SO42-/Ca2+ (1.5 and 3.5) and SO42-/NO3- (2.1 and 1.0). These differences are attributed to relative dominance of anthropogenic emissions over the northern site (Hisar). In contrast, major differences arise over Mt Abu and Nainital with respect to Cl-/Na+ (1.0 and 0.2), Ca2+/Na+ (9.0 and 4.4) and HCO3-/ Ca2+ (1.8 and 0.9) ratios; whereas SO42-/Ca2+ (2.3 and 3.1) and SO42-/NO3- (5.3 and 5.9) ratios are comparable. Such regional differences for a high altitude site could arise due to semi-arid climate and high abundance of mineral dust at Mt Abu. Higher SO42-/NO3- ratios over high altitude sites than those over low altitude sites are attributed to the relative difference in the size distribution of SO42- (fine mode) and NO3- (coarse mode) aerosols.

Effectiveness of national air pollution control policies on the air quality in metropolitan areas of China.

PubMed

Wang, Shuxiao; Xing, Jia; Zhao, Bin; Jang, Carey; Hao, Jiming

2014-01-01

Understanding the effectiveness of national air pollution controls is important for control policy design to improve the future air quality in China. This study evaluated the effectiveness of major national control policies implemented recently in China through a modeling analysis. The sulfur dioxide (SO2) control policy during the 11th Five Year Plan period (2006-2010) had succeeded in reducing the national SO2 emission in 2010 by 14% from its 2005 level, which correspondingly reduced ambient SO2 and sulfate (SO4(2-)) concentrations by 13%-15% and 8%-10% respectively over east China. The nitrogen oxides (NO(x)) control policy during the 12th Five Year Plan period (2011-2015) targets the reduction of the national NO(x) emission in 2015 by 10% on the basis of 2010. The simulation results suggest that such a reduction in NO(x) emission will reduce the ambient nitrogen dioxide (NO2), nitrate (NO3(-)), 1-hr maxima ozone (O3) concentrations and total nitrogen deposition by 8%, 3%-14%, 2% and 2%-4%, respectively over east China. The application of new emission standards for power plants will further reduce the NO2, NO3(-), 1-hr maxima O(3 concentrations and total nitrogen deposition by 2%-4%, 1%-6%, 0-2% and 1%-2%, respectively. Sensitivity analysis was conducted to evaluate the inter-provincial impacts of emission reduction in Beijing-Tianjin-Hebei and the Yangtze River Delta, which indicated the need to implement joint regional air pollution control.

Chemistry, mineralogy and origin of the clay-hill nitrate deposits, Amargosa River valley, Death Valley region, California, U.S.A.

USGS Publications Warehouse

Ericksen, G.E.; Hosterman, J.W.; St., Amand

1988-01-01

The clay-hill nitrate deposits of the Amargosa River valley, California, are caliche-type accumulations of water-soluble saline minerals in clay-rich soils on saline lake beds of Miocene, Pliocene(?) and Pleistocene age. The soils have a maximum thickness of ??? 50 cm, and commonly consist of three layers: (1) an upper 5-10 cm of saline-free soil; (2) an underlying 15-20 cm of rubbly saline soil; and (3) a hard nitrate-rich caliche, 10-20 cm thick, at the bottom of the soil profile. The saline constituents, which make up as much as 50% of the caliche, are chiefly Cl-, NO-3, SO2-4 and Na+. In addition are minor amounts of K+, Mg2+ and Ca2+, varying, though generally minor, amounts of B2O3 and CO2-3, and trace amounts of I (probably as IO-3), NO-2, CrO2-4 and Mo (probably as MoO2-4). The water-soluble saline materials have an I/Br ratio of ??? 1, which is much higher than nearly all other saline depostis. The principal saline minerals of the caliche are halite (NaCl), nitratite (NaNO3), darapskite (Na3(SO4)(NO3)??H2O), glauberite (Na2Ca(SO4)2), gypsum (CaSO4??2H2O) and anhydrite (CaSO4). Borax (Na2B4O5(OH)4??8H2O), tincalconite (Na2B4O5(OH)4??3H2O) and trona (Na3(CO3)(HCO3)??2H2O) are abundant locally. The clay-hill nitrate deposits are analogous to the well-known Chilean nitrate deposits, and probably are of similar origin. Whereas the Chilean deposits are in permeable soils of the nearly rainless Atacama Desert, the clay-hill deposits are in relatively impervious clay-rich soils that inhibited leaching by rain water. The annual rainfall in the Death Valley region of ??? 5 cm is sufficient to leach water-soluble minerals from the more permeable soils. The clay-hill deposits contain saline materials from the lake beds beneath the nitrate deposits are well as wind-transported materials from nearby clay-hill soils, playas and salt marshes. The nitrate is probably of organic origin, consisting of atmospheric nitrogen fixed as protein by photoautotrophic blue-green algae, which are thought to form crusts on soils at the sites of the deposits when moistened by rainfall. The protein is subsequently transformed to nitrate by autotophic bacteria. ?? 1988.

A kinetic study of the interaction between atomic oxygen and aerosols

NASA Technical Reports Server (NTRS)

Akers, F. I.; Wightman, J. P.

1976-01-01

This study was concerned with the effects of NH4Cl and (NH4)2SO4 aerosols on the kinetics of disappearance of atomic oxygen. Atomic oxygen was generated by a 2.45-GHz microwave discharge and the kinetics of disappearance measured in a fast flow system using NO2 titration. Values of the recombination coefficient for heterogeneous wall recombination were determined for clean, H2SO4-coated, and (NH4)2SO4-coated Pyrex to be 0.000050, 0.000020, and 0.000019, respectively. A rapid exothermic chemical reaction was found to occur between atomic oxygen and an NH4Cl wall coating; the products were NH3, NO, H2O, and HCl. The NH4Cl aerosol was generated by gas phase reaction of NH3 with HCl. The aerosol particles were approximately spherical and nearly monodisperse with a mean diameter of 1.6 plus or minus 0.2 micron. The rate constant for the disappearance of atomic oxygen in the presence of NH4Cl aerosol was measured. No significant decrease was observed in the rate of disappearance of atomic oxygen in the presence of an (NH4)2SO4 aerosol at a concentration of 285 mg per cu m.

Corrosion of cordierite ceramics by sodium sulphate at 1000 C

NASA Technical Reports Server (NTRS)

Bianco, Robert; Jacobson, Nathan

1989-01-01

The corrosion of a sintered cordierite (2MgO-2Al2O3-5SiO2) ceramic by sodium sulphate (Na2SO4) was investigated at 1000 C. Laboratory tests with thin films of Na2SO4/O2 and Na2SO4/1 percent SO2-O2 were performed. In the Na2SO4/O2 case, the cordierite reacted to form NaAlSiO4. After several hours of corrosion, the Na2SO4 appeared to induce surface cracks in the cordierite. In the Na2SO4/1 percent SO2-O2 case, other dissolution reactions occurred. The material was also tested in a burner rig with No. 2 Diesel fuel and 2 ppm sodium. The corrosion process was similar to that observed in the Na2SO4/O2 furnace tests, with more severe attack occurring.

Combined effects Na and SO2 in flue gas on Mn-Ce/TiO2 catalyst for low temperature selective catalytic reduction of NO by NH3 simulated by Na2SO4 doping

NASA Astrophysics Data System (ADS)

Zhou, Aiyi; Yu, Danqing; Yang, Liu; Sheng, Zhongyi

2016-08-01

A series of Mn-Ce/TiO2 catalysts were synthesized through an impregnation method and used for low temperature selective catalytic reduction (SCR) of NOx with ammonia (NH3). Na2SO4 was added into the catalyst to simulate the combined effects of alkali metal and SO2 in the flue gas. Experimental results showed that Na2SO4 had strong and fluctuant influence on the activity of Mn-Ce/TiO2, because the effect of Na2SO4 included pore occlusion and sulfation effect simultaneously. When Na2SO4 loading content increased from 0 to 1 wt.%, the SCR activities of Na2SO4-doped catalysts decreased greatly. With further increasing amount of Na2SO4, however, the catalytic activity increased gradually. XRD results showed that Na2SO4 doping could induce the crystallization of MnOx phases, which were also confirmed by TEM and SEM results. BET results showed that the surface areas decreased and a new bimodal mesoporous structure formed gradually with the increasing amount of Na2SO4. XPS results indicated that part of Ce4+ and Mn3+ were transferred to Ce3+ and Mn4+ due to the sulfation after Na2SO4 deposition on the surface of the catalysts. When the doped amounts of Na2SO4 increased, NH3-TPD results showed that the Lewis acid sites decreased and the Brønsted acid sites of Mn-Ce/TiO2 increased quickly, which could be considered as another reason for the observed changes in the catalytic activity. The decreased Mn and Ce atomic concentration, the changes of their oxidative states, and the variation in acidic properties on the surface of Na2SO4-doped catalysts could be the reasons for the fluctuant changes of the catalytic activity.

Influence of COD/sulfate ratios on the integrated reactor system for simultaneous removal of carbon, sulfur and nitrogen.

PubMed

Yuan, Ye; Chen, Chuan; Zhao, Youkang; Wang, Aijie; Sun, Dezhi; Huang, Cong; Liang, Bin; Tan, Wenbo; Xu, Xijun; Zhou, Xu; Lee, Duu-Jung; Ren, Nanqi

2015-01-01

An integrated reactor system was developed for the simultaneous removal of carbon, sulfur and nitrogen from sulfate-laden wastewater and for elemental sulfur (S°) reclamation. The system mainly consisted of an expanded granular sludge bed (EGSB) for sulfate reduction and organic carbon removal (SR-CR), an EGSB for denitrifying sulfide removal (DSR), a biological aerated filter for nitrification and a sedimentation tank for sulfur reclamation. This work investigated the influence of chemical oxygen demand (COD)/sulfate ratios on the performance of the system. Influent sulfate and ammonium were fixed to the level of 600 mg SO(4)(2-) L⁻¹ and 120 mg NH(4)(+) L⁻¹, respectively. Lactate was introduced to generate COD/SO(4)(2-) = 0.5:1, 1:1, 1.5:1, 2:1, 3:1, 3.5:1 and 4:1. The experimental results indicated that sulfate could be efficiently reduced in the SR-CR unit when the COD/SO(4)(2-) ratio was between 1:1 and 3:1, and sulfate reduction was inhibited by the growth of methanogenic bacteria when the COD/SO(4)(2-) ratio was between 3.5:1 and 4:1. Meanwhile, the Org-C/S²⁻/NO(3)(-) ratios affected the S(0) reclamation efficiency in the DSR unit. When the influent COD/SO(4)(2-) ratio was between 1:1 and 3:1, appropriate Org-C/S²⁻/NO(3)(-) ratios could be achieved to obtain a maximum S° recovery in the DSR unit. For the microbial community of the SR-CR unit at different COD/SO(4)(2-) ratios, 16S rRNA gene-based high throughput Illumina MiSeq sequencing was used to analyze the diversity and potential function of the dominant species.

ATMOSPHERIC CONCENTRATIONS OF AMMONIA AND AMMONIUM AT AN AGRICULTURAL SITE IN THE SOUTHEAST UNITED STATES

EPA Science Inventory

In this study, we present approximately 1 year (October 1998 - September 1999) of 12-hour mean ammonia [NH3], ammonium [NH4(+)], hydrochloric acid [HCl], nitrate [NO3(-)], nitric acid [HNO3], nitrous acid [HNO2], sulfate [SO4(- -)], and sulfur dioxide [SO2] concentrations measure...

Phase transformations of α-alumina made from waste aluminum via a precipitation technique.

PubMed

Matori, Khamirul Amin; Wah, Loy Chee; Hashim, Mansor; Ismail, Ismayadi; Zaid, Mohd Hafiz Mohd

2012-12-07

We report on a recycling project in which α-Al(2)O(3) was produced from aluminum cans because no such work has been reported in literature. Heated aluminum cans were mixed with 8.0 M of H(2)SO(4) solution to form an Al(2)(SO(4))(3) solution. The Al(2)(SO(4))(3) salt was contained in a white semi-liquid solution with excess H(2)SO(4); some unreacted aluminum pieces were also present. The solution was filtered and mixed with ethanol in a ratio of 2:3, to form a white solid of Al(2)(SO(4))(3)·18H(2)O. The Al(2)(SO(4))(3)·18H(2)O was calcined in an electrical furnace for 3 h at temperatures of 400-1400 °C. The heating and cooling rates were 10 °C /min. XRD was used to investigate the phase changes at different temperatures and XRF was used to determine the elemental composition in the alumina produced. A series of different alumina compositions, made by repeated dehydration and desulfonation of the Al(2)(SO(4))(3)·18H(2)O, is reported. All transitional alumina phases produced at low temperatures were converted to α-Al(2)O(3) at high temperatures. The X-ray diffraction results indicated that the α-Al(2)O(3) phase was realized when the calcination temperature was at 1200 °C or higher.

Phase Transformations of α-Alumina Made from Waste Aluminum via a Precipitation Technique

PubMed Central

Matori, Khamirul Amin; Wah, Loy Chee; Hashim, Mansor; Ismail, Ismayadi; Zaid, Mohd Hafiz Mohd

2012-01-01

We report on a recycling project in which α-Al2O3 was produced from aluminum cans because no such work has been reported in literature. Heated aluminum cans were mixed with 8.0 M of H2SO4 solution to form an Al2(SO4)3 solution. The Al2(SO4)3 salt was contained in a white semi-liquid solution with excess H2SO4; some unreacted aluminum pieces were also present. The solution was filtered and mixed with ethanol in a ratio of 2:3, to form a white solid of Al2(SO4)3·18H2O. The Al2(SO4)3·18H2O was calcined in an electrical furnace for 3 h at temperatures of 400–1400 °C. The heating and cooling rates were 10 °C/min. XRD was used to investigate the phase changes at different temperatures and XRF was used to determine the elemental composition in the alumina produced. A series of different alumina compositions, made by repeated dehydration and desulfonation of the Al2(SO4)3·18H2O, is reported. All transitional alumina phases produced at low temperatures were converted to α-Al2O3 at high temperatures. The X-ray diffraction results indicated that the α-Al2O3 phase was realized when the calcination temperature was at 1200 °C or higher. PMID:23222685

Role of secondary aerosols in haze formation in summer in the Megacity Beijing.

PubMed

Han, Tingting; Liu, Xingang; Zhang, Yuanhang; Qu, Yu; Zeng, Limin; Hu, Min; Zhu, Tong

2015-05-01

A field experiment from 18 August to 8 September 2006 in Beijing, China, was carried out. A hazy day was defined as visibility

Synthesis and thermoluminescence characteristics of γ-irradiated K3Ca2(SO4)3F:Eu or Ce fluoride

NASA Astrophysics Data System (ADS)

Poddar, Anuradha; Gedam, S. C.; Dhoble, S. J.

2015-05-01

New halophosphor K3Ca2(SO4)3F activated by Eu and Ce has been synthesized by a co-precipitation method and characterized according to its thermoluminescence. The formation of traps in rare earth doped K3Ca2(SO4)3F and the effects of γ-radiation dose on the glow curve are discussed. The glow curve of K3Ca2(SO4)3F:Ce shows a prominent single peak at 150°C, whereas K3Ca2(SO4)3F:Eu and K3Ca2(SO4)3F:Ce,Eu at 142°C and 192°C, respectively. A single glow peak indicates that there is only one set of trap being activated within the particular temperature range. The presented phosphors are also studied because of its fading, reusability and trapping parameters. There was just 2% fading during a period of 10 days, indicating no serious fading problem. Trapping parameters such as order of kinetics (b), activation energy (E) and frequency factor (S) were calculated by using Chen's half-width method. The observations presented in this paper are good for lamp phosphors as well as solid-state dosimeter.

Mechanistic insight into peroxydisulfate reactivity: Oxidation of the cis,cis-[Ru(bpy) 2(OH 2)] 2O 4+ "Blue Dimmer"

DOE PAGES

Hurst, James K.; Roemeling, Margo D.; Lymar, Sergei V.

2015-04-10

One-electron oxidation of the μ-oxo dimer (cis,cis-[Ru III(bpy) 2(OH 2)] 2O 4+, {3,3}) to {3,4} by S 2O 8 2- can be described by three concurrent reaction pathways corresponding to the three protic forms of {3,3}. Free energy correlations of the rate constants, transient species dynamics determined by pulse radiolysis, and medium and temperature dependencies of the alkaline pathway all suggest that the rate determining step in these reactions is a strongly non-adiabatic dissociative electron transfer within a precursor ion pair leading to the {3,4}|SO 4 2-|SO 4 •- ion triple. As deduced from the SO 4 •- scavenging experimentsmore » with 2-propanol, the SO 4 •- radical then either oxidizes {3,4} to {4,4} within the ion triple, effecting a net two-electron oxidation of {3,3}, or escapes in solution with ~25 % probability to react with additional {3,3} and {3,4}, that is, effecting sequential one-electron oxidations. The reaction model presented also invokes rapid {3,3} + {4,4} → 2 {3,4} comproportionation, for which k com ~5×10 7 M -1 s -1 was independently measured. The model provides an explanation for the observation that despite favorable energetics, no oxidation beyond the {3,4} state was detected. As a result, the indiscriminate nature of oxidation by SO 4 •- indicates that its fate must be quantitatively determined when using S 2O 8 2- as an oxidant« less

Fiber Optic Couplers

DTIC Science & Technology

1981-01-01

exchange and diffusion systems have been studied. The approaches we have tried at HRL include: (1) Li2SO2-K2so4 eutectic salt melt/soda lime glass (2...LiC1-KCL eutectic salt melt/soda lime glass (3) Ag metal field-assisted diffusion (solid phase)/soda lime glass (4) AgNO3 melt/soda lime glass (with...measurements were made of the throughput of guides formed by the ion exchange of soda lime glass in Li2SO4-K2S04 eutectic salt baths. The results of the

Impact of mine wastewaters on greenhouse gas emissions from northern peatlands used for mine water treatment

NASA Astrophysics Data System (ADS)

Palmer, Katharina; Ronkanen, Anna-Kaisa; Klöve, Björn; Hynynen, Jenna; Maljanen, Marja

2015-04-01

The amount of wastewaters generated during mining operations is increasing along with the increasing number of operation mines, which poses great challenges for mine water management and purification. Mine wastewaters contain high concentrations of nitrogen compounds such as nitrate (NO3-) and ammonium (NH4+) originating from remnant explosives as well as sulfate (SO42-) originating from the oxidation of sulfidic ores. At a mine site in Finnish Lapland, two natural peatlands have been used for cost-effective passive wastewater treatment. One peatland have been used for the treatment of drainage waters (TP 1), while the other has been used for the treatment of process-based wastewaters (TP 4). In this study, the impact of mine water derived nitrogen compounds as well as SO42- on the emission of the potent greenhouse gases methane (CH4) and nitrous oxide (N2O) from those treatment peatlands was investigated. Contaminant concentrations in the input and output waters of the treatment peatlands were monitored which allowed for the calculation of contaminant-specific retention efficiencies. Treatment peatlands showed generally good retention efficiencies for metals and metalloids (e.g. nickel, arsenic, antimony, up to 98% reduction in concentration) with rather low input-concentrations (i.e., in the μg/l-range). On the other hand, retention of contaminants with high input-concentrations (i.e., in mg/l-range) such as NO3-, NH4+ and SO42- was much lower (4-41%, 30-60% and -42-30%, respectively), indicating the limited capability of the treatment peatlands to cope with such high input concentrations. NO3- and NH4+ concentrations were determined in surface and pore water from TP 4 in July 2013 as well as in surface water from TP 1 and TP 4 in October 2013. Up to 720 μM NO3- and up to 600 μM NH4+ were detected in surface water of TP 4 in July 2013. NO3- and NH4+ concentrations in surface waters were highest near the mine wastewater distribution ditch and decreased with increasing distances from the ditch. NO3- concentrations were lower in pore water than in surface water, and the peak in NO3- concentration shifted further away from the distribution ditch with increasing depth. On the contrary, NH4+ concentrations were generally higher in pore water than in surface water, and peak concentrations increased with increasing depth. Highest NH4+ concentrations were detected in 30 to 60 cm depth near the outlet at the south end of TP 4. Fluxes of the greenhouse gases CH4 and N2O from 4 sampling points (2 from TP 4, 1 from TP 1, 1 from reference area) were measured on 7 different occasions 2013 and 2014. CH4 emissions were in the same range as measured in other northern pristine peatlands in the reference area, which is not influenced by mine wastewaters. Treatment peatlands showed only very minor CH4 emissions or even CH4 uptake. On the other hand, treatment peatlands showed high N2O emissions, which were in the same range as N2O emissions observed from northern peat soils used for agriculture. Highest emissions were generally observed near the wastewater distribution ditch of TP 4. N2O emissions from the reference area were negligible or even negative. NO3-, NH4+ and SO42- concentrations were determined from surface waters from each sampling point and sampling occasion. N2O emissions were positively correlated with NO3- concentrations, indicating denitrification-derived N2O production in treatment peatlands. On the other hand, CH4 emissions were negatively correlated with SO42- and NO3- concentrations, indicating that the presence of alternative electron acceptors in large amounts suppresses CH4 production in treatment peatlands. In conclusion, the study revealed that (i) treatment peatlands receive high loads of NO3-, NH4+ and SO42- which are not well retained in the peatlands, (ii) mine wastewaters positively and negatively affect N2O and CH4 emissions, respectively, (iii) N2O emissions are positively correlated with NO3- concentrations, and (iv) CH4 emissions are negatively correlated with NO3- and SO42- concentrations. This study thus illustrates the pronounced impacts of mine wastewaters on processes involved in greenhouse gas turnover in peatlands ecosystems.

Behaviour of complexes of f-elements in the environment - An experimental and theoretical analysis

NASA Astrophysics Data System (ADS)

Ivanova, Bojidarka; Spiteller, Michael

2017-01-01

The paper provides a comprehensive study of lanthanide and actinide complexes to a matter of key area in the field of the chemistry, i.e. environmental analytical chemistry. The content has involved: (i) solution and sorption behaviour of lanthanides (Lnn+, Ln = Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Py, Ho, Er, Tm, Yb and Lu) onto Y(O)O(H) minerals (Y = Fe, Mn or Si); (ii) ligand exchange processes with participation of inorganic OH-, F-, Cl-, Br-, SO42-, SO32-, IO3-, NO32-, CO32- and/or HCO3- ligands as well as mixed ligand complexes, including solvent molecules such as {[LnOR]2+}, {[Ln(OR)2]+} (R = CH3OH, CH3CH2CH2OH) and {[Ln(CH3CN)x(H2O)z]3+} (x = 6-8, z = 0-4); (iii) the actinide speciation has involved different oxidation states (+4)-(+6) and ions {[UOH]3+}, {[UX]3+} (X = F or Cl), {[UFx]y+/-} (x = 2-6, y = 0-2), {[U(CO3)x]y-} (x = 4 or 5, y = 4 or 6), {[U(SO4)]2+], {[U(NO3)]3+}, {[U(NO3)2]2+}, [[UO2(CO3)3]5-}, {[(UO2)x(OH)z]y+/-} (x = 1-4, y = 1 or 2, z = 1-7), {[UO2Fx]y+/-} (x = 1-4, y = 1 or 2), {[UO2(CO3)x]y-} (x = 2, or 3, y = 2, or 4), {[(UO2)2(CO3)(OH)3]-}, {[(UO2)3O(OH)2(HCO3)]+}, {[(UO2)11(CO3)6(OH)12]2-}, {[UO2(SO4)x]y-}, (x = 2 or 3, y = 2 or 4), {[UO2SiO(OH)3]+}, {[AnCx]y+/-} (x,y = 1 and 2), {[CAnH]+/-}, {[CxAny]0} (x,y = 2 and 3), {[AnHx]y+} (x = 1-3, y = 0-5), {[AnXn]m+/-} (n = 1-6, m = 1-4, X = F-, Br-, I-), {[AnOxFz]y+/-} (x, z = 1 or 2, y = 0, 1 and 2), {[AnNx]y+} (x = 1 and 2), {[AnxOz(OH)n]y+/-} (x = 1-3, z = 1-4, y = 0, 1 or 2, n = 0 or 1) and Ann+ (n = 0-6) at An = Th, Pa, U, Np, Pu, Am, Cm, Bk, Cf, Es, Fm, Md, No and Lr, respectively. Correlation analysis between thermodynamic parameters, accounting for different surface interactions of adsorbed species and experimental mass spectrometric data, including liquid, semi-liquid and solid-state measurements in a large set of experimental conditions such as pH = 2-13, low and intermediate ionic strength, solvent type, ε = 0-78.0, variety of solvent proton accepting and donating numbers and T = 25-400 °C has carried out.

Chemical composition and sources of coastal marine aerosol particles during the 2008 VOCALS-REx campaign

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Y. -N.; Springston, S.; Jayne, J.

2014-01-01

The chemical composition of aerosol particles ( D p ≤ 1.5 μm) was measured over the southeast Pacific Ocean during the VAMOS (Variability of the American Monsoon Systems) Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-Rex) between 16 October and 15 November 2008 using the US Department of Energy (DOE) G-1 aircraft. The objective of these flights was to gain an understanding of the sources and evolution of these aerosols, and of how they interact with the marine stratus cloud layer that prevails in this region of the globe. Our measurements showed that the marine boundary layer (MBL) aerosol mass was dominated bymore » non-sea-salt SO 4 2−, followed by Na +, Cl −, Org (total organics), NH 4 +, and NO 3 −, in decreasing order of importance; CH 3SO 3 − (MSA), Ca 2+, and K + rarely exceeded their limits of detection. Aerosols were strongly acidic with a NH 4 + to SO 4 2− equivalents ratio typically < 0.3. Sea-salt aerosol (SSA) particles, represented by NaCl, exhibited Cl − deficits caused by both HNO 3 and H 2SO 4, but for the most part were externally mixed with particles, mainly SO 4 2−. SSA contributed only a small fraction of the total accumulation mode particle number concentration. It was inferred that all aerosol species (except SSA) were of predominantly continental origin because of their strong land-to-sea concentration gradient. Comparison of relative changes in median values suggests that (1) an oceanic source of NH 3 is present between 72° W and 76° W, (2) additional organic aerosols from biomass burns or biogenic precursors were emitted from coastal regions south of 31° S, with possible cloud processing, and (3) free tropospheric (FT) contributions to MBL gas and aerosol concentrations were negligible. Finally, the very low levels of CH 3SO 3 − observed as well as the correlation between SO 4 2− and NO 3 − (which is thought primarily anthropogenic) suggest a limited contribution of DMS to SO 4 2− aerosol production during VOCALS.« less

INORGANIC PM2.5 AT A U.S. AGRICULTURAL SITE

EPA Science Inventory

In this study, we present approximately two years (January 1999–December 2000) of atmospheric NH₃, NH₄⁺, HCl, Cl^-, HNO₃, NO₃^-, SO₂, and SO₄⁼ concentrations measured by t...

Health risk of inhalation exposure to sub-10 µm particulate matter and gaseous pollutants in an urban-industrial area in South Africa: an ecological study.

PubMed

Morakinyo, Oyewale Mayowa; Adebowale, Ayo Stephen; Mokgobu, Matlou Ingrid; Mukhola, Murembiwa Stanley

2017-03-13

To assess the health risks associated with exposure to particulate matter (PM 10 ), sulphur dioxide (SO 2 ), nitrogen dioxide (NO 2 ), carbon monoxide (CO) and ozone (O 3 ). The study is an ecological study that used the year 2014 hourly ambient pollution data. The study was conducted in an industrial area located in Pretoria West, South Africa. The area accommodates a coal-fired power station, metallurgical industries such as a coke plant and a manganese smelter. Estimate of possible health risks from exposure to airborne PM 10 , SO 2 , NO 2 , CO and O 3 was performed using the US Environmental Protection Agency human health risk assessment framework. A scenario-assessment approach where normal (average exposure) and worst-case (continuous exposure) scenarios were developed for intermediate (24-hour) and chronic (annual) exposure periods for different exposure groups (infants, children, adults). The normal acute (1-hour) exposure to these pollutants was also determined. Presence or absence of adverse health effects from exposure to airborne pollutants. Average annual ambient concentration of PM 10 , NO 2 and SO 2 recorded was 48.3±43.4, 11.50±11.6 and 18.68±25.4 µg/m 3 , respectively, whereas the South African National Ambient Air Quality recommended 40, 40 and 50 µg/m 3 for PM 10 , NO 2 and SO 2 , respectively. Exposure to an hour's concentration of NO 2 , SO 2 , CO and O 3 , an 8-hour concentration of CO and O 3 , and a 24-hour concentration of PM 10 , NO 2 and SO 2 will not likely produce adverse effects to sensitive exposed groups. However, infants and children, rather than adults, are more likely to be affected. Moreover, for chronic annual exposure, PM 10 , NO 2 and SO 2 posed a health risk to sensitive individuals, with the severity of risk varying across exposed groups. Long-term chronic exposure to airborne PM 10 , NO 2 and SO 2 pollutants may result in health risks among the study population. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Influence of pH and ionic strength (NaCl/Na2SO4) on the reaction HO Cl/ClO- + NO2-

NASA Astrophysics Data System (ADS)

Marcellos da Rosa, M.; Zetzsch, C.

2003-04-01

Equilibria such as HOCl + NO_2^- leftrightarrow ClNO_2 + OH^- and ClNO_2 + H_2O leftrightarrow NO_3^- + 2H^+ + Cl^- play an important role in halogen activation in the troposphere. We studied the oxidation of NO_2^- by HOCl/ClO^- in aqueous phase by stopped-flow measurements at different ionic strengths (bidestilled water, 0.1M NaCl, 1.0M NaCl and 1.0M Na_2SO^4) at various pH values (4.0, 5.5, 6.2 and 10.0) at 293K. The experiments were performed using a SX.18MV Applied Photophysics spectrophotometer, observing the exponential decay of HOCl/ClO^- at λ = 290nm between 10ms and 100s. HOCl (pK_a= 7.50) was obtained by bubbling N_2 with 1% Cl_2 through bidestilled water. The pH of the aqueous solutions of HOCl was determined by a pH meter (CG820, Schott) with a glass electrode N6180 (calibrated with standard buffer solutions at pH = 3.0, 4.0, 7.0 and 10.0), and the pH values were adjusted by dropwise addition of HClO_4 or NaOH. The concentrations of HOCl (ɛHOCl (230nm) = 100M-1cm-1) ([HOCl] = 1.3mM - 10mM) and ClO- (ɛClO- (292nm) = 350 M-1cm-1) ([ClO^-] = 1.3mM - 5mM) were determined by UV spectrometry (Kontron UVIKON 860) at a resolution of 2 nm in 1 cm cells at various pH values. The concentration range of NO_2^- was between 5mM and 50mM. The following second-order rate constant kII were obtained at 293K at various pH values (in units of M-1s-1) in H_2O: pH 4.0, (5.6±0.3)\\cdot 10^3; pH 5.5, (5.0±0.4)\\cdot 10^3; pH 10.0, 3.9±0.4; in 0.1M NaCl: pH 5.5, (4.3±0.4)\\cdot 10^3; pH 10.0, 2.6±0.4; in 1.0M NaCl: pH 5.5, (4.0±0.3); pH 10.0, 0.7±0.2 and in 1.0M Na_2SO_4: pH 5.5, (3.0±0.3)\\cdot 10^3; pH 10.0, 1.9±0.4. There is a strong effect of the pH on the reaction HOCl/ClO^- + NO_2^-, as reflected in the ratio kII_a(pH 5.5, HOCl)/kII_b(pH 10.0, ClO^-): in H_2O (kII_a ˜ 1200 \\cdot kII_b), in 0.1M NaCl (kII_a ˜ 1900 \\cdot kII_b), in 1.0M NaCl (kII_a ˜ 5700 \\cdot kII_b) and in 1.0 M Na_2SO_4 (kII_a ˜ 1500 \\cdot kII_b). A mechanism for the oxidation of NO_2^- by HOCl/ClO^- will be presented and compared with previous work.

Seasonal variations and size distributions of water-soluble ions of atmospheric particulate matter at Shigatse, Tibetan Plateau.

PubMed

Yang, Yongjie; Zhou, Rui; Yan, Yan; Yu, Yue; Liu, Junqing; Di, Yi'an; Du, Zhenyu; Wu, Dan

2016-02-01

Size-segregated atmospheric particulate matter (PM) samples were collected from July 2012 to September 2013 at Shigatse, high-altitude (3836 m above sea level) site on the south Tibetan Plateau (TP); objectives were to determine the characteristics and size distribution of water-soluble ions (WSIs). Eight major WSIs (Na(+), K(+), Mg(2+), Ca(2+), NH4(+), Cl(-), SO4(2-), and NO3(-)) were detected by ion chromatography. The total concentrations of WSIs were 6370 ± 1916 ng m(-3) in dry season (October - December, January - April), and 5261 ± 769 ng/m(3) during wet phase (May - September). The contribution of K(+) (130 ng m(-3)), Cl(-) (2035 ng m(-3)), SO4(2-) (1176 ng m(-3)), and NO3(-) (706 ng m(-3))(-)were significantly enhanced in dry season, and that of Na(+) (455 ng m(-3)), Mg(2+)(65.4 ng m(-3)), Ca(2+)(1034 ng m(-3)), and NH4(+) (1948 ng m(-3)) were significantly enhanced during wet phase. Mg(2+) and Ca(2+) were concentrated in the coarse mode, and the other ions concentrated in fine mode and coarse mode during two seasons. The correlation coefficients between K(+) and NH4(+), Cl(-), SO4(2-) and NO3(-) were 0.58 (P < 0.01), 0.40 (P < 0.05), 0.82 (P < 0.01) and 0.69 (P < 0.01), indicating their dominant contribution from biomass burning in dry season. The significant correlation between NH4(+) and HCO3(-) which were calculated by ion balance (r = 0.89, P < 0.01), suggesting the source from nitrogen fertilizers during wet phase. Copyright © 2015 Elsevier Ltd. All rights reserved.

Pollutant-induced cell death and reactive oxygen species accumulation in the aerial roots of Chinese banyan (Ficus microcarpa)

NASA Astrophysics Data System (ADS)

Liu, Nan; Cao, Ce; Sun, Zhongyu; Lin, Zhifang; Deng, Rufang

2016-11-01

Industrial pollutants induce the production of toxic reactive oxygen species (ROS) such as O2.-, H2O2, and ·OH in plants, but they have not been well quantified or localized in tissues and cells. This study evaluated the pollutant- (HSO3-, NH4NO3, Al3+, Zn2+, and Fe2+) induced toxic effects of ROS on the aerial roots of Chinese banyan (Ficus microcarpa). Root cell viability was greatly reduced by treatment with 20 mM NaHSO3, 20 mM NH4NO3, 0.2 mM AlCl3, 0.2 mM ZnSO4, or 0.2 mM FeSO4. Biochemical assay and histochemical localization showed that O2.- accumulated in roots in response to pollutants, except that the staining of O2.- under NaHSO3 treatment was not detective. Cytochemical localization further indicated that the generated O2.- was present mainly in the root cortex, and pith cells, especially in NH4NO3- and FeSO4-treated roots. The pollutants also caused greatly accumulated H2O2 and ·OH in aerial roots, which finally resulted in lipid peroxidation as indicated by increased malondialdehyde contents. We conclude that the F. microcarpa aerial roots are sensitive to pollutant-induced ROS and that the histochemical localization of O2.- via nitrotetrazolium blue chloride staining is not effective for detecting the effects of HSO3- treatment because of the treatment’s bleaching effect.

Change of brown coal oxidation kinetic characteristics by promoting additives appending in the form of copper salts

NASA Astrophysics Data System (ADS)

Larionov, K. B.; Mishakov, I. V.; Gromov, A. A.; Zenkov, A. V.

2017-11-01

Process of brown coal oxidation with 5%wt content of copper-salt additives of various nature (Cu (NO3)2, CuSO4 and Cu(CH3COO)2) was studied. The experiment has been performed by thermogravimetric analysis at a heating rate of 2.5°C/min to a maximum temperature of 600°C in the air. Analytical evaluation of oxidation process kinetic characteristics has been conducted based on the results of TGA. It has been established that addition of initiating agents leads to significant reduction in the initial ignition temperature of coal (ΔTi = 15÷40°C), shortening of the sample warm-up time to the ignition point (Δte = 6÷12 min) and reduction of the sample burning time (Δtf = 40÷54 min). The following series of additives activity affecting ignition temperature of coals has been established: Cu(CH3COO)2 > Cu(NO3)2 > CuSO4. Additionally, the opposite can be said about the effect of additives on residence time of the sample in its combustion area (CuSO4 > Cu(NO3)2 > Cu(CH3COO)2). According to mass spectrometric analysis, presence of NOx, SO2, CO2 (intense peaks at 190÷290°C) was recorded in oxidation products of modified samples, which is explained by partial or complete decomposition of salts.

Chemical Composition Characteristics of Atmospheric Aerosols in Relation to Haze, Asian Dust and Mixed Haze-Asian Dust Episodes at Background Site of Korea in 2013

NASA Astrophysics Data System (ADS)

KO, H.; Song, J. M.; Cha, J. W.; Kang, C. H.; Kim, J.; Ryoo, S. B.

2016-12-01

The PM10 and PM2.5 aerosols were collected at the Gosan site of Jeju Island, Korea in 2013 and analyzed, in order to examine the variation characteristics of chemical compositions in relation to haze, Asian dust, and mixed haze-Asian dust episodes. For the haze event, nitrate concentrations increased highly as 8.8 and 25.1 times for PM10 and PM2.5, respectively, possibly caused by the inflow of air mass stagnated in eastern parts of China into Jeju area. For the Asian dust event, the concentrations of nss-Ca2+, NO3- and nss-SO42- increased 6.0, 1.5, 1.8 times for PM10, and 2.3, 1.3, 1.6 times for PM2.5, respectively. Meanwhile, for the mixed haze-Asian dust event, the concentrations of nss-Ca2+ and NO3- increased 13.4 and 3.2 times for PM10, and 1.8 and 3.4 times for PM2.5, respectively. The NH4NO3 content was higher than that of (NH4)2SO4 during the haze event, however it was relatively low during the mixed haze-Asian dust event. NO3-/nss-SO42- concentration ratios of Asian Dust in PM10 and PM2.5 were 0.4 and 0.2, showing less significant effect from automobile and local pollution sources. The aerosols were acidified mostly by inorganic acids, especially the nitric acid contributed highly to the acidification during both haze and mixed haze-Asian dust events. Meanwhile, the neutralization by ammonia was noticeably high during haze event when the stagnated air mass moved from China.

Effects of nitrate and water on the oxygen isotopic analysis of barium sulfate precipitated from water samples

USGS Publications Warehouse

Hannon, Janet E.; Böhlke, John Karl; Mroczkowski, Stanley J.

2008-01-01

BaSO4 precipitated from mixed salt solutions by common techniques for SO isotopic analysis may contain quantities of H2O and NO that introduce errors in O isotope measurements. Experiments with synthetic solutions indicate that δ18O values of CO produced by decomposition of precipitated BaSO4 in a carbon reactor may be either too low or too high, depending on the relative concentrations of SO and NO and the δ18O values of the H2O, NO, and SO. Typical δ18O errors are of the order of 0.5 to 1‰ in many sample types, and can be larger in samples containing atmospheric NO, which can cause similar errors in δ17O and Δ17O. These errors can be reduced by (1) ion chromatographic separation of SO from NO, (2) increasing the salinity of the solutions before precipitating BaSO4 to minimize incorporation of H2O, (3) heating BaSO4under vacuum to remove H2O, (4) preparing isotopic reference materials as aqueous samples to mimic the conditions of the samples, and (5) adjusting measured δ18O values based on amounts and isotopic compositions of coexisting H2O and NO. These procedures are demonstrated for SO isotopic reference materials, synthetic solutions with isotopically known reagents, atmospheric deposition from Shenandoah National Park, Virginia, USA, and sulfate salt deposits from the Atacama Desert, Chile, and Mojave Desert, California, USA. These results have implications for the calibration and use of O isotope data in studies of SO sources and reaction mechanisms.

Ionized-Cluster Beam/Partially Ionized Beam Deposition of Electro- Optical and Nonlinear Optical Organic Materials and Device Development

DTIC Science & Technology

1993-08-29

4’- CH3 O--\\\\4 4N -2 nitrostilbene NO 2J (MMONS) 4’-dimethylamfino OCH3 -N-4-stylbazolium j, o3 - 200 3125 1000 tosylate (DAST)or 0 3 (CH3)2N CH3 Styrylpyridinium PH cyanine dye 400 1490 470 ( SPCD ) SO4 (CH3 ½2N lh3 20

Measurement of fine particulate matter water-soluble inorganic species and precursor gases in the Alberta Oil Sands Region using an improved semicontinuous monitor.

PubMed

Hsu, Yu-Mei; Clair, Thomas A

2015-04-01

The ambient ion monitor-ion chromatography (AIM-IC) system, which provides hourly measurements of the main chemical components of PM2.5 (particulate matter with an aerodynamic diameter<2.5 μm) and its precursor gases, was evaluated and deployed from May to July 2011 and April to December 2013 in the Athabasca Oil Sands Region (AOSR) of northeastern Alberta, Canada. The collection efficiencies for the gas-phase SO2 and HNO3 using the cellulose membrane were 96% and 100%, respectively, and the collection efficiency of NH3 using the nylon membrane was 100%. The AIM-IC was compared with a collocated annular denuder sampling system (ADSS) and a Federal Reference Method (FRM) Partisol PM2.5 sampler. The correlation coefficients of SO4(2-) concentrations between the AIM-IC and ADSS and between the AIM-IC and the Partisol PM2.5 sampler were 0.98 and 0.95, respectively. The comparisons also showed no statistically significant difference between the measurement sets, suggesting that the AIM-IC measurements of the PM2.5 chemical composition are comparable to the ADSS and Partisol PM2.5 methods. NH3 concentration in the summer (mean±standard deviation, 1.9±0.7 µg m(-3)) was higher than in the winter (1.3±0.9 µg m(-3)). HNO3 and NO3- concentrations were generally low in the AOSR, and especially in the winter months. NH4+ (0.94±0.96 µg m(-3)) and SO4(2-) (0.58±0.93 µg m(-3)) were the major ionic species of PM2.5. Direct SO2 emissions from oil sands processing operations influenced ambient particulate NH4+ and SO4(2-) values, with hourly concentrations of NH4+ and SO4(2-) measured downwind (~30 km away from the stack) at 10 and 28 µg m(-3). During the regional forest fire event in 2011, high concentrations of NO3-, NH4+, HNO3, NH3, and PM2.5 were observed and the corresponding maximum hourly concentrations were 31, 15, 9.6, 89, and >450 (the upper limit of PM2.5 measurement) µg m(-3), suggesting the formation of NH4NO3. The AOSR in Canada is one of the most scrutinized industrial regions in the developed world due to the extent of oil extraction activities. Because of this, it is important to accurately assess the effect of these operations on regional air quality. In this study, we compare a new analytical approach, AIM-IC, with more standard analytical approaches to understand how local anthropogenic and nonanthropogenic sources (e.g., forest fires) impact regional air quality. With this approach, we also better characterize PM2.5 composition and its precursor gases to understand secondary aerosol formation mechanisms and to better identify possible control techniques if needed.

Increasing ammonia concentration trends in large regions of the USA derived from the NADP/AMoN network

NASA Astrophysics Data System (ADS)

Butler, T.; Vermeylen, F.; Lehmann, C. M.; Likens, G. E.; Puchalski, M.

2016-12-01

Data from bi-weekly passive samplers from 18 of the longest operating National Atmospheric Deposition Program's (NADP) Ammonia Monitoring Network (AMoN) sites (most operating from 2008 to 2015) show that concentrations of NH3 have been increasing (p-value < 0.0001) over large regions of the USA. This trend is occurring at a seasonal and annual level of aggregation. Using random coefficient models (RCM), the mean slope for the 18 sites combined shows an increase of NH3 concentration of +7% per year, with a 95% confidence interval (C.I.) from +5% to +9% per year. Travel blank corrected data using the same approach show increasing NH3 concentrations of +9% (95% C.I. +5% to +13%) per year. During a comparable period (2008-2014) NADP precipitation chemistry sites in the same regions show significant increasing (p-value = 0.0001) precipitation NH4+ concentrations trends for all sites combined of +5% (95% C.I. +3% to +7%) per year. Emissions inventory data for the study period show nearly constant rates of NH3 emissions, but large reductions in NOx and SO2 emissions. Seasonal air quality data from the Clean Air Status and Trends Network (CASTNET) sites in these regions show significant declines in atmospheric particulate SO42- and NH4+, and particulate NO3- plus HNO3 (total NO3-) during the same period. Less formation of acidic SO4 and NO3, due to reduced SO2 and NOx emissions, provide less substrate to interact with NH3 and form particulate ammonium species. Thus, concentrations of NH3 can increase in the atmosphere even if emissions remain constant. A likely result may be more localized deposition of NH3, as opposed to the more long-range transport and deposition of ammonium nitrate (NH4NO3) and sulfate (NH4)2SO4). Additionally, the spatial distribution of wet and dry acidic deposition will be impacted.

Ion balance and acidity of size-segregated particles during haze episodes in urban Beijing

NASA Astrophysics Data System (ADS)

Tian, Shili; Pan, Yuepeng; Wang, Yuesi

2018-03-01

In this study, we investigated how the ion balance causes variations in size segregated aerosol acidity and atmospheric processing on clean versus hazy days using a 9-stage sampler. We calculated the ratios (in charge equivalents, RC/A) between measured cations (Na+, NH4+, K+, Mg2 +, and Ca2 +) and anions (SO42 -, NO3- and Cl-) for different aerosol size fractions. The ratios were typically close to unity in the accumulation mode (0.65-2.1 μm), and increased significantly when the particle size increased or decreased. In the coarse size range (aerodynamic diameter > 2.1 μm), high RC/A values were most likely caused by the undetermined CO32- and HCO3- content of the mineral dust. In contrast, the high RC/A values for submicron aerosols (< 1.1 μm) were likely caused by the presence of water-soluble organic anions. The RC/A values for all size fractions were lower on hazy days than clean days, indicating that aerosol acidity was enhanced on polluted days. Simiar temporal trend between RC/A and in-situ pH indicated that RC/A was a good indicator of aerosol acidity in fine mode aerosol. The SO42 - and NO3- contents in fine particles were completely neutralized as the RC/A values for PM2.1 approached unity, and mean values of RC/A were 1.34 and 1.16 during the transition and polluted periods, respectively. The lowest RC/A values were observed in the size fraction with the highest concentrations of SO42 -, NO3- and NH4+ (SNA) and concentrations of SNA increased with the increasing aerosol acidity. Significant correlations between [NO3-]/[SO42 -] and [NH4+]/[SO42 -] during NH4+-rich conditions in fine size fractions indicated fine mode NO3- in Beijing was mainly formed by gas-phase homogeneous reaction between the ambient NH3 and HNO3.

Effects of Simulated Nitrogen Deposition on Soil Net Nitrogen Mineralization in the Meadow Steppe of Inner Mongolia, China

PubMed Central

Liu, Xing-ren; Ren, Jian-qiang; Li, Sheng-gong; Zhang, Qing-wen

2015-01-01

Effects of simulated nitrogen (N) deposition on soil net nitrogen mineralization (NNM) were examined in situ during two growing seasons, using the resin-core technique in the semiarid meadow steppe in Inner Mongolia, China. The aim of this study is to clarify the effect of N levels (0, 10, and 20 kg N ha−1yr−1) and forms (NH4 + and NO3 -) on soil mineral N and NNM. Our results showed that N levels had no significant differences on soil mineral N and NNM. In the first year, three N treatments ((NH4)2SO4, NH4Cl and KNO3) increased soil NH4 + concentrations but had no significant effects on soil NO3 - concentrations. In the second year, (NH4)2SO4 treatment increased soil NO3 - concentrations, NH4Cl and KNO3 treatments decreased them. Three N treatments significantly decreased soil NH4 + concentrations in the later stages of the second year. As for the soil NNM, three N treatments had no significant effects on the rates of soil NNM (R m) and net nitrification (R n) in the first year, but significantly decreased them in the second year. The contribution of N addition to Rm was higher from (NH4)2SO4 than from NH4Cl and KNO3. However, Soil R m was mainly affected by soil water content (SWC), accumulated temperature (Ta), and soil total N (TN). These results suggest that the short-term atmospheric N deposition may inhibit soil NNM in the meadow steppe of Inner Mongolia. PMID:26218275

NO2-initiated multiphase oxidation of SO2 by O2 on CaCO3 particles

NASA Astrophysics Data System (ADS)

Yu, Ting; Zhao, Defeng; Song, Xiaojuan; Zhu, Tong

2018-05-01

The reaction of SO2 with NO2 on the surface of aerosol particles has been suggested to be important in sulfate formation during severe air pollution episodes in China. However, we found that the direct oxidation of SO2 by NO2 was slow and might not be the main reason for sulfate formation in ambient air. In this study, we investigated the multiphase reaction of SO2 with an O2 / NO2 mixture on single CaCO3 particles using Micro-Raman spectroscopy. The reaction converted the CaCO3 particle to a Ca(NO3)2 droplet, with CaSO4 ⚫ 2H2O solid particles embedded in it, which constituted a significant fraction of the droplet volume at the end of the reaction. The reactive uptake coefficient of SO2 for sulfate formation was on the order of 10-5, which was higher than that for the multiphase reaction of SO2 directly with NO2 by 2-3 orders of magnitude. According to our observations and the literature, we found that in the multiphase reaction of SO2 with the O2 / NO2 mixture, O2 was the main oxidant of SO2 and was necessary for radical chain propagation. NO2 acted as the initiator of radical formation, but not as the main oxidant. The synergy of NO2 and O2 resulted in much faster sulfate formation than the sum of the reaction rates with NO2 and with O2 alone. We estimated that the multiphase oxidation of SO2 by O2 initiated by NO2 could be an important source of sulfate and a sink of SO2, based on the calculated lifetime of SO2 regarding the loss through the multiphase reaction versus the loss through the gas-phase reaction with OH radicals. Parameterization of the reactive uptake coefficient of the reaction observed in our laboratory for further model simulation is needed, as well as an integrated assessment based on field observations, laboratory study results, and model simulations to evaluate the importance of the reaction in ambient air during severe air pollution episodes, especially in China.

Chemical composition and source apportionment of PM2.5 during heavy pollution episodes in 2013-2015 in Handan, China

NASA Astrophysics Data System (ADS)

Ma, X.; Wang, L.; Tan, J.; Meng, C.; Zhang, F.; Ma, S.; Wei, Z.; Zhang, C.; Zhao, L.; Ji, S.

2017-12-01

To investigate the formation mechanism of heavy air pollution in Handan, China, a comprehensive dataset including continuous online hourly observations of the meteorological parameters and air pollutants, i.e., SO2 NO, NO2, NOx, CO, O3, in January, 2013-2015, as well as water-soluble inorganic ions (WSII) (NO3-, SO42-, NH4+, Cl-, Na+, Mg2+, K+, Ca2+), carbon components (OC, EC) and inorganic elements in PM2.5 are analyzed in this study. The HYSPLIT Trajectory Model is applied to analyze the transport pathway of air mass. NO, SO2 and PM2.5 showed an obvious decreasing trend. Compared with 2013, NO, SO2 and PM2.5 decreased by 12.1%, 25.5%, 7.6% and 12.5%, 33.5%, 30.9% in 2014 and 2015, respectively. Heavy pollution episodes were often observed in winter during this period. A severe pollution episode was occurred from 2 to 20 January 2013. The peak concentrations of PM2.5 and PM10 were 1144.3 μg/m3 and 780.2 μg/m3 on 11 January 2013, respectively. The polluted level of heavy pollution episodes in 2014 and 2015 were slighter than 2013, but still can't be ignored. Their durations were short and generally lasted about 4-7 days, however, the frequency of occurrence was increased. Low temperature and wind speed and high humidity were always observed during these pollution episodes. The concentrations of chemical compositions of PM2.5 during heavy pollution episodes were significantly higher than those in clean day. The concentrations of SNA (SO42-, NO3- and NH4+) and OC peaked at 12 January 2013, 16 January 2014 and 15 January 2015, respectively, which is consistent with the previous analysis. The average monthly concentrations of SO42- and NH4+ were in the order of: 2013>2014>2015, indicating that this was related to the decrease of SO2 concentration. Cu, Zn, Pb were highly enriched elements, indicating the industrial pollution, especially from iron and steel smelting had a significant contribution to PM2.5 in Handan. Additionally, Cr in 2015, Mn, Co in 2014 and 2015 were highly enriched elements, respectively. Finally, the major spatial sources of pollutants in Handan are local emissions and from Hebei Province. The short-distance trajectories in January accounted for 63%, 64%, 50%, respectively.

Glyoxal and Methylglyoxal Setschenow Salting Constants in Sulfate, Nitrate, and Chloride Solutions: Measurements and Gibbs Energies.

PubMed

Waxman, Eleanor M; Elm, Jonas; Kurtén, Theo; Mikkelsen, Kurt V; Ziemann, Paul J; Volkamer, Rainer

2015-10-06

Knowledge about Setschenow salting constants, KS, the exponential dependence of Henry's Law coefficients on salt concentration, is of particular importance to predict secondary organic aerosol (SOA) formation from soluble species in atmospheric waters with high salt concentrations, such as aerosols. We have measured KS of glyoxal and methylglyoxal for the atmospherically relevant salts (NH4)2SO4, NH4NO3, NaNO3, and NaCl and find that glyoxal consistently "salts-in" (KS of -0.16, -0.06, -0.065, -0.1 molality(-1), respectively) while methylglyoxal "salts-out" (KS of +0.16, +0.075, +0.02, +0.06 molality(-1)). We show that KS values for different salts are additive and present an equation for use in atmospheric models. Additionally, we have performed a series of quantum chemical calculations to determine the interactions between glyoxal/methylglyoxal monohydrate with Cl(-), NO3(-), SO4(2-), Na(+), and NH4(+) and find Gibbs free energies of water displacement of -10.9, -22.0, -22.9, 2.09, and 1.2 kJ/mol for glyoxal monohydrate and -3.1, -10.3, -7.91, 6.11, and 1.6 kJ/mol for methylglyoxal monohydrate with uncertainties of 8 kJ/mol. The quantum chemical calculations support that SO4(2-), NO3(-), and Cl(-) modify partitioning, while cations do not. Other factors such as ion charge or partitioning volume effects likely need to be considered to fully explain salting effects.

Processes controlling the composition of precipitation at a remote southern hemispheric location: Torres del Paine National Park, Chile

NASA Astrophysics Data System (ADS)

Galloway, James N.; Keene, William C.; Likens, Gene E.

1996-03-01

Precipitation composition measured at Torres del Paine National Park, Chile (TdP) (51°10'S, 71°58'W), between 1984 and 1993 was acidic (volume-weighted-average pH of 4.96) with a dilute seawater component. H+ was the dominant non-sea-salt (nss) cation; in decreasing order of abundance, nss anions were HCOO-, Cl-, SO4=, CH3COO-, and NO3-. Relative to lower latitude, remote locations, concentrations and per-event depositions of nss SO4=, NO3-, and NH4+ at TdP were lower; those of HCOOt (HCOO- + HCOOH) and CH3COOHt, (CH3COO- and CH3COOH) were similar; and those of CH3SO3- were higher. Concentrations and deposition fluxes of HCOOt, CH3COOt, nss SO4=, CH3SO3-, and NH4+ varied seasonally with summer maxima and winter minima. Carboxylic acids probably originated from both direct terrestrial emissions and oxidation of hydrocarbons emitted by marine and terrestrial biota. Nss SO4= and CH3SO3- originated primarily from oxidation of biogenic (CH3)2S emitted from the southern Pacific Ocean. Direct emissions of NH3 from upwind terrestrial and marine ecosystems probably accounted for most observed NH4+. NO3- concentrations and depositions were highest during the latter part of austral winter and spring suggesting abiotic controls. Transport of precursors from lightning, biomass burning, and fossil-fuel combustion at lower latitudes and possibly transport of reactive N from the stratosphere apparently contributed oxidized N to the southern Patagonian troposphere. Although the ionic strength of precipitation at TdP is currently among the world's lowest, future changes are likely because of increases in local and regional population and energy and food production.

Biotic and abiotic processes controlling water chemistry during snowmelt at rabbit ears pass, Rocky Mountains, Colorado, U.S.A.

USGS Publications Warehouse

Peters, N.E.; Leavesley, G.H.

1995-01-01

The chemical composition of snowmelt, groundwater, and streamwater was monitored during the spring of 1991 and 1992 in a 200-ha subalpine catchment on the western flank of the Rocky Mountains near Steamboat Springs, Colorado. Most of the snowmelt occurred during a one-month period annually that began in mid-May 1991 and mid-April 1992. The average water quality characteristics of individual sampling sites (meltwater, streamwater, and groundwater) were similar in 1991 and 1992. The major ions in meltwater were differentially eluted from the snowpack, and meltwater was dominated by Ca2+, SO4/2-, and NO3/-. Groundwater and streamwater were dominated by weathering products, including Ca2+, HCO3/- (measured as alkalinity), and SiO2, and their concentrations decreased as snowmelt progressed. One well had extremely high NO3/- concentrations, which were balanced by Ca2+ concentrations. For this well, hydrogen ion was hypothesized to be generated from nitrification in overlying soils, and subsequently exchanged with other cations, particularly Ca2+. Solute concentrations in streamwater also decreased as snowmelt progressed. Variations in groundwater levels and solute concentrations indicate thai most of the meltwater traveled through the surficial materials. A mass balance for 1992 indicated that the watershed retained H+, NH4/+, NO3/-, SO4/2- and Cl- and was the primary source of base cations and other weathering products. Proportionally more SO4/2- was deposited with the unusually high summer rainfall in 1992 compared to that released from snowmelt, whereas NO3/- was higher in snowmelt and Cl- was the same. The sum of snowmelt and rainfall could account for greater than 90% of the H+ and NH4/+ retained by the watershed and greater than 50% of the NO3/-.The chemical composition of snowmelt, groundwater, and streamwater was monitored during the spring of 1991 and 1992 in a 200-ha subalpine catchment on the western flank of the Rocky Mountains near Steamboat Springs, Colorado. The major ions in meltwater were differentially eluted from the snowpack, and meltwater was dominated by Ca2+, SO42-, and NO3-. Groundwater and streamwater were dominated by weathering products and their concentrations decreased as snowmelt progressed. Solute concentrations in streamwater also decreased as snowmelt progressed. A mass balance for 1992 showed that the watershed retained H+, NH4+, NO3-, SO42- and Cl- and was the primary source of base cations and other weathering products.

Asian Dust Observed During the KORUS Air Quality Mission Creates Significant Super-Micron NO3-, NH4+, and SO42- Aerosols.

NASA Astrophysics Data System (ADS)

Heim, E. W.; Dibb, J. E.; Scheuer, E. M.

2017-12-01

The KORUS mission was a collaborative effort between the Korean Institute of Environmental Research and NASA. KORUS provided a comprehensive assessment of air quality in Korea during early 2016. The intensive sampling campaign was timed to assess local photochemistry during increasing solar insolation and biogenic emissions; after the April peak in outflow of pollution and dust from central China. Chinese outflow is well characterized by Silica-Calcium rich dust. Despite the effort to avoid the period with strongest dust outflow, Ca2+ was well represented in all bulk (particle diameters up to 4.5 micron) aerosol filter samples < 3 kilometers altitude (m = 0.640 ug/m3, s = 0.759, n=880). In particular, four flights were heavily impacted by Chinese outflow :(m = 1.607 ug/m3, s = 1.149, n = 152). Back trajectories from the flight tracks of these 4 flights indicate transport from desert regions in north central China. This dust presents a basic surface for the abundant anthropogenic acids (HNO3, H2SO4) to interact with. In combination with abundant anthropogenic NH3 these acids react with CaCO3 contained in the dust in cyclic reactions that form dust cores covered in a shell of acid-base reaction products. The difference between bulk filter measurements and submicron measurements of NH4+, SO42, and NO3- made by AMS indicates substantial super-micron fractions of these anthropogenic ions at times during KORUS-AQ. During the dustiest samples (Ca2+ > 1.5ug/m3) we see marked increases in super-micron concentration of NH4+, SO42-, and NO3-, m = 1.113 ug/m3 , 2.621 ug/m3 , 4.413 ug/m3, with the super-micron contribution to total concentration averaging 47%, 45%, and 81% respectively. In contrast, low dust days (Ca2+ < 0.2ug/m3) the super-micron concentrations averaged 0.262 ug/m3, 0.510 ug/m3, -0.029 ug/m3, respectively and accounted for just 20%, 14%, and 8% of total mass. During the dust events, samples that have trajectories passing over industrial centers in eastern China approached equivalence balance between Ca2++ NH4+ and SO42-+NO3-. In contrast dusty samples that did not pass over these industrial centers during transport to the West Sea and Korea maintained excess cations, dominantly Ca2+. This suggests that dust can act as an important carrier of Chinese pollution to Korea when this saturated dust reaches the peninsula.

40 CFR Figure C-1 to Subpart C of... - Suggested Format for Reporting Test Results for Methods for SO 2, CO, O 3, NO 2

Code of Federal Regulations, 2011 CFR

2011-07-01

... Results for Methods for SO 2, CO, O 3, NO 2 C Figure C-1 to Subpart C of Part 53 Protection of Environment... Pt. 53, Subpt. C, Fig. C-1 Figure C-1 to Subpart C of Part 53—Suggested Format for Reporting Test... Difference Table C-1 spec. Pass or fail Low 1 ____ ppm 2 to ____ ppm 3 4 5 6 Medium 1 ____ ppm 2 to ____ ppm...

40 CFR Figure C-1 to Subpart C of... - Suggested Format for Reporting Test Results for Methods for SO 2, CO, O 3, NO 2

Code of Federal Regulations, 2014 CFR

2014-07-01

... Results for Methods for SO 2, CO, O 3, NO 2 C Figure C-1 to Subpart C of Part 53 Protection of Environment... Pt. 53, Subpt. C, Fig. C-1 Figure C-1 to Subpart C of Part 53—Suggested Format for Reporting Test... Difference Table C-1 spec. Pass or fail Low 1 ____ ppm 2 to ____ ppm 3 4 5 6 Medium 1 ____ ppm 2 to ____ ppm...

40 CFR Figure C-1 to Subpart C of... - Suggested Format for Reporting Test Results for Methods for SO 2, CO, O 3, NO 2

Code of Federal Regulations, 2012 CFR

2012-07-01

... Results for Methods for SO 2, CO, O 3, NO 2 C Figure C-1 to Subpart C of Part 53 Protection of Environment... Pt. 53, Subpt. C, Fig. C-1 Figure C-1 to Subpart C of Part 53—Suggested Format for Reporting Test... Difference Table C-1 spec. Pass or fail Low 1 ____ ppm 2 to ____ ppm 3 4 5 6 Medium 1 ____ ppm 2 to ____ ppm...

40 CFR Figure C-1 to Subpart C of... - Suggested Format for Reporting Test Results for Methods for SO 2, CO, O 3, NO 2

Code of Federal Regulations, 2010 CFR

2010-07-01

... Results for Methods for SO 2, CO, O 3, NO 2 C Figure C-1 to Subpart C of Part 53 Protection of Environment... Pt. 53, Subpt. C, Fig. C-1 Figure C-1 to Subpart C of Part 53—Suggested Format for Reporting Test... Difference Table C-1 spec. Pass or fail Low 1 ____ ppm 2 to ____ ppm 3 4 5 6 Medium 1 ____ ppm 2 to ____ ppm...

Evaluation of metal mobility from copper mine tailings in northern Chile.

PubMed

Lam, Elizabeth J; Gálvez, M E; Cánovas, M; Montofré, I L; Rivero, D; Faz, A

2016-06-01

This work shows the results obtained on a copper mine tailing in the Antofagasta Region, Chile. The tailing was classified as saline-sodic with high concentrations of metals, especially Cu and Fe, with pH 8.4. Our objectives were to (1) compare the physicochemical properties of the tailing with surrounding soils of the mine under study, and (2) evaluate the effect of two amendments (CaCO3 and compost) and their mixtures on Cu(2+), Mn, Fe, Zn, Mg(2+), and K(+) and Ca(2+), SO4 (2-), NO3 (-), and PO4 (3-) leaching. The data obtained were submitted to variance and covariance analysis. The results from the comparison between both substrates showed that in general, the tailing presented greater content of metals. Regarding tailing leaching, pH, electrical conductivity (EC), and concentration of the elements of interest were measured. The statistical analysis showed that Cu(2+) leaching and immobilization of Fe occurred to the greatest extent with compost. The EC decreased throughout the experiment with irrigation and increased upon treatment with compost. The major interactions found among the chemical parameters were (1) tailings without treatment, Cu(2+)/Fe and NO3 (-)/SO4 (2-); (2) tailings treated with CaCO3, Cu(2+)/K(+); (3) tailings treated with compost, NO3 (-)/SO4 (-2) and EC/Cu(2+); and (4) tailings treated with both amendments, EC/Fe and Cu(2+)/Fe. The ANOVA showed that the number of irrigations and the amendments statistically significantly affected the copper mobility and the organic amendment significantly influenced the iron mobility.

Performances and application of a passive sampling method for the simultaneous determination of nitrogen dioxide and sulfur dioxide in ambient air.

PubMed

Plaisance, H; Sagnier, I; Saison, J Y; Galloo, J C; Guillermo, R

2002-11-01

The performances and applicability of a diffusion tube sampler for the simultaneous measurements of NO2 and SO2 in ambient air were evaluated. SO2 and NO2 are collected by the passive sampler using triethanolamine as trapping agent and are determined as sulphate and nitrite with ion chromatography. The detection limit (2.3 microg m(-3) of NO2 and 4.2 microg m(-3) of SO2 for two weeks sampling) is adequate for the determination of concentrations in urban and industrial areas. Precision of the method as RSD is in mean 5% for NO2 and 12% for SO2 at the concentration levels in urban areas. Calibration of the method was performed in the field conditions by comparison between the responses of sampler and the concentrations measured by the continuous monitors. High degree of linearity (correlation coefficients > 0.8) is found between the passive sampler tube and the continuous monitor data for both NO2 and SO2. To reduce the wind velocity influence on passive sampling of diffusion tubes, a protective shelter was tested in this study. The overall uncertainty of one measure for the optimised method is estimated at 5 microg m(-3) for NO2 and 6 microg m(-3) for SO2. Suitability of this passive sampling method for air pollution monitoring in urban areas was demonstrated by the results shown in this paper on a campaign carried out in the French agglomeration.

Gaseous emissions and modification of slurry composition during storage and after field application: Effect of slurry additives and mechanical separation.

PubMed

Owusu-Twum, Maxwell Yeboah; Polastre, Adele; Subedi, Raghunath; Santos, Ana Sofia; Mendes Ferreira, Luis Miguel; Coutinho, João; Trindade, Henrique

2017-09-15

The aim of the study was to evaluate the impact of slurry treatment by additives (EU200 ® (EU200), Bio-buster ® (BB), JASS ® and sulphuric acid (H 2 SO 4 )) and mechanical separation on the physical-chemical characteristics, gaseous emissions (NH 3 , CH 4 , CO 2 and N 2 O) during anaerobic storage at ∼20 °C (experiment 1) and NH 3 losses after field application (experiment 2). The treatments studied in experiment 1 were: whole slurry (WS), WS+H 2 SO 4 to a pH of 6.0, WS+EU200 and WS+BB. Treatments for experiment 2 were: WS, slurry liquid fraction (LF), composted solid fraction (CSF), LFs treated with BB (LFB), JASS ® (LFJ), H 2 SO 4 to a pH of 5.5 (LFA) and soil only (control). The results showed an inhibition of the degradation of organic materials (cellulose, hemicellulose, dry matter organic matter and total carbon) in the WS+H 2 SO 4 relative to the WS. When compared to the WS, the WS+H 2 SO 4 increased electrical conductivity, ammonium (NH 4 + ) and sulphur (S) concentrations whilst reducing slurry pH after storage. The WS+H 2 SO 4 reduced NH 3 volatilization by 69% relative to the WS but had no effect on emissions of CH 4 , CO 2 and N 2 O during storage. Biological additive treatments (WS+EU200 and WS+BB) had no impact on slurry characteristics and gaseous emissions relative to the WS during storage. After field application, the cumulative NH 3 lost in the LF was almost 50% lower than the WS. The losses in the LFA were reduced by 92% relative to the LF. The LFB and LFJ had no impact on NH 3 losses relative to the LF. A significant effect of treatment on NH 4 + concentration was found at the top soil layer (0-5 cm) after NH 3 measurements with higher concentrations in the LF treatments relative to the WS. Overall, the use of the above biological additives to decrease pollutant gases and to modify slurry characteristics are questionable. Reducing slurry dry matter through mechanical separation can mitigate NH 3 losses after field application. Slurry acidification can increase the fertilizer value (NH 4 + and S) of slurry whilst mitigating the environmental impacts through a decrease in NH 3 losses during storage and after application. Copyright © 2017 Elsevier Ltd. All rights reserved.

A PRINCIPAL COMPONENT ANALYSIS OF THE CLEAN AIR STATUS AND TRENDS NETWORK (CASTNET) AIR CONCENTRATION DATA

EPA Science Inventory

The spatial and temporal variability of ambient air concentrations of SO₂, SO₄^2-, NO₃, HNO₃, and NH₄⁺ obtained from EPA's CASTNet was examined using an objective, statistically based technique...

Silver(I) coordination polymers assembled from flexible cyclotriphosphazene ligand: structures, topologies and investigation of the counteranion effects.

PubMed

Davarcı, Derya; Gür, Rüştü; Beşli, Serap; Şenkuytu, Elif; Zorlu, Yunus

2016-06-01

The reactions of a flexible ligand hexakis(3-pyridyloxy)cyclotriphosphazene (HPCP) with a variety of silver(I) salts (AgX; X = NO3(-), PF6(-), ClO4(-), CH3PhSO3(-), BF4(-) and CF3SO3(-)) afforded six silver(I) coordination polymers, namely {[Ag2(HPCP)]·(NO3)2·H2O}n (1), {[Ag2(HPCP)(CH3CN)]·(PF6)2}n (2), {[Ag2(HPCP)(CH3CN)]·(ClO4)2}n (3), [Ag3(HPCP)(CH3PhSO3)3]n (4), [Ag2(HPCP)(CH3CN)(BF4)2]n (5) and {[Ag(HPCP)]·(CF3SO3)}n (6). All of the isolated crystalline compounds were structurally determined by X-ray crystallography. Changing the counteranions in the reactions, which were conducted under similar conditions of M/L ratio (1:1), temperature and solvent, resulted in structures with different types of topologies. In complexes (1)-(6), the ligand HPCP shows different coordination modes with Ag(I) ions giving two-dimensional layered structures and three-dimensional frameworks with different topologies. Complex (1) displays a new three-dimensional framework adopting a (3,3,6)-connected 3-nodal net with point symbol {4.6(2)}2{4(2).6(10).8(3)}. Complexes (2) and (3) are isomorphous and have a two-dimensional layered structure showing the same 3,6L60 topology with point symbol {4.2(6)}2{4(8).6(6).8}. Complex (4) is a two-dimensional structure incorporating short Ag...Ag argentophilic interactions and has a uninodal 4-connected sql/Shubnikov tetragonal plane net with {4(4).6(2)} topology. Complex (5) exhibits a novel three-dimensional framework and more suprisingly contains twofold interpenetrated honeycomb-like networks, in which the single net has a trinodal (2,3,5)-connected 3-nodal net with point symbol {6(3).8(6).12}{6(3)}{8}. Complex (6) crystallizes in a trigonal crystal system with the space group R\\bar 3 and possesses a three-dimensional polymeric structure showing a binodal (4,6)-connected fsh net with the point symbol (4(3).6(3))2.(4(6).6(6).8(3)). The effect of the counteranions on the formation of coordination polymers is discussed in this study.

[Water-soluble anions of atmosphere on Tianwan nuclear power station].

PubMed

Zhao, Heng-Qiang; He, Ying; Zheng, Xiao-Ling; Chen, Fa-Rong; Pang, Shi-Ping; Wang, Cai-Xia; Wang, Xiao-Ru

2010-11-01

Three major water-soluble anions (Cl-, SO4(2-) and NO3-) in the atmosphere of the Tianwan nuclear power station in Lianyungang were determined by ion chromatography from June 2005 to May 2006. The results showed that the annual average concentration of Cl-, SO4(2-) and NO3- in the atmosphere of Tianwan nuclear power station was (33.12 +/- 53.63) microg x m(-3), (53.34 +/- 30.34) microg x m(-3) and (8.34 +/- 4.47) microg x m(-3), respectively. The concentrations of the three water-soluble anions showed evident trend of seasonal variation. The concentrations of Cl-, SO4(2-) reached the highest level in summer and the lowest level in winter, while the concentration of NO3- in autumn and winter was higher than those in summer and spring. Meteorological parameters such as wind direction, wind speed, temperature and relative humidity were studied and showed definite influence to the anions concentration of the atmosphere. This is the first simultaneous monitoring of corrosive anions in the atmosphere of Chinese coastal nuclear power plant, and it will provide basis for the prevention of marine atmospheric corrosion, which will ensure the safely operating of our nuclear power industry.

A field study on chemistry, S(IV) oxidation rates and vertical transport during fog conditions

NASA Astrophysics Data System (ADS)

Joos, F.; Baltensperger, U.

An extensive fog study was carried out in the central plateu of Switzerland. Ninety-seven fog samples were collected along with aerosol filter and cascade impactor samples, and measurements of O 3, SO 2, NO, NO x, PAN, temperature, and wind speed and direction. Maximum levels in fogwater were 4.3, 4.4., 0.033, 1.7, 0.5, 0.024 and 9.2 mmol ℓ -1 for Cl -, NO 3-, NO 2-, SO 42-, S(IV), oxalate and NH 4+, respectively. pH varied between 2.9 and 7.1. Sixteen additional elements were determined in the fog samples by ICP. The sum of the concentrations of SO 42- and S(IV) agreed very with the total sulfur concentration as determined by ICP. A substantial excess of S(IV) (up to 0.2 mmol ℓ -1) compared to Henry and acid-base equilibrium calculations was found, which can probably be attributed to complex formations with aldehydes. S(IV) oxidation rates of up to 650 nmol ℓ -1 s -1 with ozone and of up to 100 nmol ℓ -1 s -1 with NO 2 were calculated. S(IV) oxidation due to PAN, NO 2- and Fe(III) was of minor importance. A substantial fraction of the major ions was present in the intersitial aerosol (aerosol particles < 4 μm) even during fog conditions. High correlations were found for NH 4+, NO 32-. From their ratios in the fog water and the aerosol (< 4 μm) it could be concluded that at least 40% of NO 3- and 20% of NH 4+ in fog water was due to gas phase scavenging. Increasing concentrations in fog water were found during fog dissipation. Concentrations decreased with increasing height. A vertical transport model including turbulent diffusion and droplet sedimentation is introduced, which matches the experimental data of this vertical profile.

Evolution of a recombinant (gucoamylase-producing) strain of Fusarium venenatum A3/5 in chemostat culture.

PubMed

Wiebe, M G; Robson, G D; Shuster, J; Trinci, A P

2001-04-20

Fusarium venenatum JeRS 325 is a transformant of strain A3/5 which produces Aspergillus niger glucoamylase (GAM) under the control of a Fusarium oxysporum trypsin-like protease promoter. The evolution of JeRS 325 was studied in glucose-limited chemostat cultures grown on NaNO3 or (NH4)2SO4 as the nitrogen source. Thirteen mutants which were more highly branched and four mutants which were more sparsely branched than the parental strain were isolated from the NaNO3 chemostat. The highly branched mutants detected in this chemostat did not displace the sparsely branched population. The mutants isolated from the NaNO3 chemostat complemented representative strains previously isolated from glucose-limited chemostat cultures of F. venenatum A3/5 grown on (NH4)2SO4, but showed little complementation between themselves. By contrast, a highly branched mutant isolated from the (NH4)2SO4 chemostat culture displaced the sparsely branched mycelial population. None of the mutants isolated from the NaNO3 or (NH4)2SO4 chemostats produced as much GAM as JeRS 325. Southern blot analysis showed that all except one mutant had lost copies of both the glucoamylase and the acetamidase (the selectable marker) genes. However, specific GAM production was not necessarily correlated with the extent of glaA gene loss observed. Further, 10 of the mutants had lost the ability to grow on acetamide as the sole nitrogen source, although they retained copies of the amdS gene. In competition studies, mutants which could not utilize acetamide displaced mutants which could. The presence of foreign DNA in JeRS 325 resulted in a reduced specific growth rate (compared to A3/5), but the presence of the foreign DNA did not prevent the evolution of the strain or the isolation of mutants which had improved growth rates. Copyright 2001 John Wiley & Sons, Inc.

AMBIENT AMMONIA AND AMMONIUM AEROSOL ACROSS A REGION OF VARIABLE AMMONIA EMISSION DENSITY

EPA Science Inventory

The paper presents one year of ambient ammonia (NH₃), ammonium (NH₄⁺), hydrochloric acid (HCI), chloride (CI¯), nitric acid (HNO₃), nitrate (NO₃¯), nitrous acid (HONO), sulfur dioxide (SO₂), and sulfate (SO₄

Characteristics of Atmospheric Pollution in Handan, China

NASA Astrophysics Data System (ADS)

Zhang, P.; Wang, L.; Zhao, X.; Yang, J.; Wei, Z.; Su, J.; Zhang, F.; Meng, C.

2013-12-01

Handan, located in the southern edge of Hebei province, is one of the cities with worst air pollution in China. Based on the data from our comprehensive air quality monitoring station in Handan from August 2012 to January 2013, a series studies on the characteristics of air pollution in Handan were conducted. The daily mean concentration of PM10 and PM2.5 was 231.5 μg/m3 and 125.8 μg/m3 which exceeded daily National Ambient Air Quality Standard II (NAAQS) of China by 54.3% and 67.7% respectively. The highest daily concentration of them was 863.9 μg/m3 and 643.0 μg/m3, appeared on January 11, 2013, exceeding NAAQS by 475.9% and 757.3% respectively. Mean ratio of PM2.5/PM10 was 0.53. High PM2.5/PM10 ratio frequently occurred in winter, especially January (0.63) and February (0.65). Average daily concentration of SO2, NOx, NO2 and CO was 118 μg/m3, 133 μg/m3, 60.4 μg/m3 and 3210 μg/m3 respectively. The maximum daily average concentration of them was 393 μg/m3, 352 μg/m3, 135 μg/m3, 9660 μg/m3 which was 2.62, 3.52, 2.69, 2.42 times of daily NAAQS. The average concentration of total water soluble ions (TWSI) in PM2.5 from October 13 to December 21, 2012 was 69.57 μg/m3 which accounted for 61.67% of PM2.5. NO3-, SO42-, Cl- and NH4+ were the most important components of water soluble ionic composition in PM2.5.their concentration was 21.20 μg/m3, 16.96 μg/m3,8.43 μg/m3 and 14.81 μg/m3, accounted for 18.8%, 15.03% ,7.47% and 13.13% in PM2.5, respectively. Concentration of NO3- and SO42- had a good correlation (R2 = 0.807). The daily average concentration of OC and EC was 22.17 μg/m3, 6.29 μg/m3, accounted for 19.65%, 5.58% in PM2.5 respectively. The average ratio of OC/EC was 3.44, which shows that there is secondary organic carbon (SOC) in carbonaceous aerosol. Chemical characteristics of PM2.5 in Beijing, Tianjin and Handan were very similar. Most of Daily visibility values (67.4%) were lower than 5 km from August 2012 to January 2013. Daily visibility above 16 km was very scarce in Handan. Mean value of daily visibility was only 4.4×3.5 km in the range of 0.3 to 15.6 km. Average daily value of BC, NO, O3, RH, temperature, pressure was 9.3 μg/m3, 35.7 ppb, 20.6 ppb, 64.4%, 12.1 degree and 1011.2 hPa respectively. During the most polluted period from January 6 to January 31, 2013, mean daily visibility was 0.9 km. Average value of BC, NO, RH, temperature and pressure was 20.4 μg/m3, 98.4 ppb, 89.2%, -1.9 degree and 1015.9 hPa respectively. Visibility showed negative correlation with BC, RH, NO2, PM2.5, NOx, PM10, NO, CO, SO2, pressure and showed positive correlation with O3 and temperature. The most related four parameters with visibility were BC, RH, NO2 and PM2.5. The least related four parameters with visibility were O3, temperature, SO2 and pressure. Empirical model was developed to investigate the complex relationships between visibility, meteorological and pollutant parameters. The modeling result was as following: The model computed visibility had good consistence with the observed values.

Aerosol composition, chemistry, and source characterization during the 2008 VOCALS Experiment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Y.; Springston, S.; Jayne, J.

2010-03-15

Chemical composition of fine aerosol particles over the northern Chilean coastal waters was determined onboard the U.S. DOE G-1 aircraft during the VOCALS (VAMOS Ocean-Cloud-Atmosphere-Land Study) field campaign between October 16 and November 15, 2008. SO42-, NO3-, NH4+, and total organics (Org) were determined using an Aerodyne Aerosol Mass Spectrometer, and SO42-, NO3-, NH4+, Na+, Cl-, CH3SO3-, Mg2+, Ca2+, and K+ were determined using a particle-into-liquid sampler-ion chromatography technique. The results show the marine boundary layer (MBL) aerosol mass was dominated by non- sea-salt SO42- followed by Na+, Cl-, Org, NO3-, and NH4+, in decreasing importance; CH3SO3-, Ca2+, and K+more » rarely exceeded their respective limits of detection. The SO42- aerosols were strongly acidic as the equivalent NH4+ to SO42- ratio was only {approx}0.25 on average. NaCl particles, presumably of sea-salt origin, showed chloride deficits but retained Cl- typically more than half the equivalency of Na+, and are externally mixed with the acidic sulfate aerosols. Nitrate was observed only on sea-salt particles, consistent with adsorption of HNO3 on sea-salt aerosols, responsible for the Cl- deficit. Dust particles appeared to play a minor role, judging from the small volume differences between that derived from the observed mass concentrations and that calculated based on particle size distributions. Because SO42- concentrations were substantial ({approx}0.5 - {approx}3 {micro}g/m3) with a strong gradient (highest near the shore), and the ocean-emitted dimethylsulfide and its unique oxidation product, CH3SO3-, were very low (i.e., {le} 40 parts per trillion and <0.05 {micro}g/m3, respectively), the observed SO42- aerosols are believed to be primarily of terrestrial origin. Back trajectory calculations indicate sulfur emissions from smelters and power plants along coastal regions of Peru and Chile are the main sources of these SO4- aerosols. However, compared to observations, model calculations appeared to underestimate sulfate concentrations based on an existing emission inventory. The agreement between observations and model predictions of CO as well as total sulfur is reexamined in this work with a new emission inventory made available recently.« less

Development of an in situ fiber optic Raman system to monitor hydrothermal vents.

PubMed

Battaglia, Tina M; Dunn, Eileen E; Lilley, Marvin D; Holloway, John; Dable, Brian K; Marquardt, Brian J; Booksh, Karl S

2004-07-01

The development of a field portable fiber optic Raman system modified from commercially available components that can operate remotely on battery power and withstand the corrosive environment of the hydrothermal vents is discussed. The Raman system is designed for continuous monitoring in the deep-sea environment. A 785 nm diode laser was used in conjunction with a sapphire ball fiber optic Raman probe, single board computer, and a CCD detector. Using the system at ambient conditions the detection limits of SO(4)(2-), CO(3)(2-) and NO(3)(-) were determined to be approximately 0.11, 0.36 and 0.12 g l(-1) respectively. Mimicking the cold conditions of the sea floor by placing the equipment in a refrigerator yielded slightly worse detection limits of approximately 0.16 g l(-1) for SO(4)(-2) and 0.20 g l(-1) for NO(3)(-). Addition of minerals commonly found in vent fluid plumes also decreased the detection limits to approximately 0.33 and 0.34 g l(-1) respectively for SO(4)(-2) and NO(3)(-).

[Dynamics of nitrogen and sulfur wet deposition in typical forest stand at different spatial levels in Simian Mountain, mid-subtropical region].

PubMed

Sun, Tao; Ma, Ming; Wang, Ding-yong; Huang, Li-xin

2014-12-01

In order to investigate the dynamics of nitrogen and sulfur wet deposition in subtropical forest ecosystem, one typical forest stand, evergreen broad-leaved forest, at Simian Mountain located in Chongqing was selected in this research. Based on field monitoring, effects of precipitation, throughfall, litterfall, and groundwater runoff of the typical forest stand on the quality of water of Simian Mountain were investigated from September 2012 to August 2013. Results showed that the rainfall of Simian Mountain was apparently acidic, with average pH of 4.89 and maximum pH of 5.14. The soil, canopies and trunks could increase pH of precipitation, with soils having the maximum increment, followed by the forest canopy. Forest canopy had the function of adsorption and purification of NO3-, NO2- and SO4(2-), and the average entrapment rate was 56.68%, 45.84% and 35.51%, respectively. Moreover, the degradation of litter was probably the main reason for the increase of ion concentrations in the surface litter water. Forest soils could absorb and neutralize NO3-, SO2- and NH4+, and release NO2-. The evergreen broad-leaf forest of mid-subtropical region had the function of interception on NO3-, NO2-, NH4+ and SO4(2-), and the total entrapment rate was 92.86%, 57.86%, 87.24% and 87.25%, respectively, and it had a certain buffering function for the acid rain.

Association between air pollution and upper respiratory tract infection in hospital outpatients aged 0-14 years in Hefei, China: a time series study.

PubMed

Li, Y R; Xiao, C C; Li, J; Tang, J; Geng, X Y; Cui, L J; Zhai, J X

2018-03-01

To investigate the association between air pollution and upper respiratory tract infection (URTI) in children aged 0-14 years in Hefei, China in 2014-2015. An ecological method (i.e. generalised additive model [GAM]) was used to explore the effects of air pollutants on paediatric hospital outpatients with URTI. GAM was used to evaluate the lag effects (including lag0 to lag6, lag01 and lag06) between daily changes in particulate matter (PM 10 ), fine particulate matter (PM 2.5 ), sulphur dioxide (SO 2 ), nitrogen dioxide (NO 2 ), ozone (O 3 ) and carbon monoxide (CO) and the number of hospital outpatients with URTI in 2014-2015, after controlling for the confounding effects of long-term trends, seasonality, day of the week, public holidays and meteorological factors. PM 10 , PM 2.5 , SO 2 , NO 2 and CO in the single-pollutant models had significant positive effects on the number of paediatric hospital outpatients with URTI. It was found that per 10 μg/m 3 increasing in concentrations of PM 10 at lag3, PM 2.5 , SO 2 , NO 2 and CO at lag06 were associated with an increase of Excess risk (ER) with 0.15% (95% CI: 0.07%∼0.23%), 0.38% (95% CI: 0.17%∼0.60%), 2.92% (95% CI: 1.88%∼3.97%), 4.47% (95% CI: 3.69%∼5.25%) and 0.05% (95% CI: 0.02%∼0.08%), respectively. Only NO 2 remained significantly positively associated with the number of hospital outpatients with URTI in the full-pollutant models, and ERs were 4.72% (95% CI = 3.76%-5.69%) and 4.70% (95% CI = 3.76%-5.65%) per 10 μg/m 3 increase in NO 2 in Model 1 (including PM10, SO 2 , NO 2 , O 3 and CO) and Model 2 (including PM 2.5 , SO 2 , NO 2 , O 3 and CO), respectively. This study showed that short-term exposure to air pollution was associated with increased risk of URTI among paediatric hospital outpatients aged 0-14 years in Hefei. NO 2 was the major air pollutant affecting the daily number of paediatric hospital outpatients with URTI. Copyright © 2017 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

Selective autocatalytic reduction of NO from sintering flue gas by the hot sintered ore in the presence of NH3.

PubMed

Chen, Wangsheng; Luo, Jing; Qin, Linbo; Han, Jun

2015-12-01

In this paper, the selective autocatalytic reduction of NO by NH3 combined with multi-metal oxides in the hot sintered ore was studied, and the catalytic activity of the hot sintered ore was investigated as a function of temperature, NH3/NO ratio, O2 content, H2O and SO2. The experimental results indicated that the hot sintered ore, when combined with NH3, had a maximum denitration efficiency of 37.67% at 450 °C, 3000 h(-1) gas hourly space velocity (GHSV) and a NH3/NO ratio of 0.4/1. Additionally, it was found that O2 played an important role in removing NOx. However, high O2 content had a negative effect on NO reduction. H2O was found to promote the denitration efficiency in the absence of SO2, while SO2 inhibited the catalytic activity of the sintered ore. In the presence of H2O and SO2, the catalytic activity of the sintered ore was dramatically suppressed. Copyright © 2015 Elsevier Ltd. All rights reserved.

Application of ion chromatography to the determination of water-soluble inorganic and organic ions in atmospheric aerosols.

PubMed

Yu, Xue-Chun; He, Ke-Bin; Ma, Yong-Liang; Yang, Fu-Mo; Duan, Feng-Kui; Zheng, Ai-Hua; Zhao, Cheng-Yi

2004-01-01

A simple, sensitive and convenient ion chromatography(IC) method was established for the simultaneous determination of twelve water-soluble inorganic anions(F- , Cl- , NO2(-), NO3(-), SO3(2-), SO4(2-) , PO4(3-)), and fifteen water-soluble organic ions(formate, acetate, MSA, oxalate, malonate, succinate, phthalates, etc.) in atmospheric aerosols. The linear concentrations ranged from 0.005 microg/m3 to 500 microg/m3 ( r = 0.999-0.9999). The relative standard deviation (RSD) were 0.43%-2.00% and the detection limits were from 2.7 ng/m3 to 88 ng/m3. The proposed method was successfully applied to the simultaneous determination of those inorganic ions and organic ions in PM2.5 of Beijing.

The Kinetic Nonequilibrium Processes in the Internal Flow and in the Plume of Subsonic and Supersonic Aircrafts

NASA Technical Reports Server (NTRS)

Starik, Alexander M.

1997-01-01

(1) Our results show that under combustion of thermal destruction products of n-C8H18, and other hydrocarbon fuels with air at the equivalent ratio -0.5 and less the chemical equilibrium is not realized at the exit plane of combustion chamber and in the gas turbine and nozzle for most of small components such as NO2, NO3, HNO, HNO2, HNO3, N(x)H(y), HO2, OH. The chemical equilibrium is not realized in the internal flow of ramjet hydrogen combustion engine too. So at the nozzle exit plane both of gas-turbine hydrocarbon combustion engine and of ramjet hydrogen combustion engine the relatively large values of concentration of such small components as NO3, HNO2, N2O, HNO3, HNO, NH, N2H, HO2, H2O2 may be realized. The exact definition of these component concentration as well as concentration of NO(x), OH, SO2, O, H, H2, H2O at the nozzle exit plane is very important for plume chemistry. (2) The results which were obtained for subsonic and hypersonic aircrafts indicate on the considerable change of the composition of the gas mixture along the plume. This change can be caused not only by the mixture of combustion products with the atmosphere air but by proceeding of whole complex of nonequilibrium photochemical reactions. The photodissociation processes begin to influence on the formation of the free atoms and radicals at flight altitude H greater than or equal to 18 km. Neglect of these processes can result in essential (up to 10(exp 4) times) mistakes of values gamma(sub OH), gamma(sub O), gamma(sub H), gamma(sub HSO3) and some products of CFC's disintegration. It was found that penetration of Cl-containing species from the atmosphere into the exhaust flow and its interaction with nitrogen oxides leads to essential increasing of the concentration of Cl, Cl2, ClO2, ClNO3, CH3Cl and sometimes HCl and the decreasing of ClO concentration by comparison with background values. The results of our analysis show that the plume aircraft with both hydrocarbon and hydrogen combustion engine may be source of various pollutant components such as HNO, HNO4,ClO2, CH3NO2, CH3NO3, CH2O, Cl, H2O2, but not only NO, NO2, HNO2, HNO3, N2O5, SO2, SO3, H2SO4 as it was supposed before.

[Transformation Mechanism and Sources of Secondary Inorganic Components in PM2.5 at an Agriculture Site (Quzhou) in the North China Plain in Summer].

PubMed

Chen, Shi-yi; Zeng, Li-min; Dong, Hua-bin; Zhu, Tong

2015-10-01

Simultaneously on-line measurements of major water-soluble inorganic ions and gaseous pollutants were performed from June 9 to July 11, 2014 at Quzhou, an agriculture site in the North China Plain using a gas-aerosol collector (GAC) and ion chromatograph (IC), aiming to track the diurnal variation rule of secondary inorganic components and gas-phase precursors as well as their interactions. The transformation mechanism and sources of fine particles (PM2.5) were also discussed. The results showed that these water-soluble ions in PM2.5 and their gas-phase precursors varied regularly. As the dominant ionic components of PM2.5 (accounting for 76.23%), the average concentrations of SO4(2-), NH4(+), NO3(-) were 26.28 μg x m(-3), 18.08 μg x m(-3) and 16.36 μg m(-3) respectively. Among the precursor gases, the NH3, generated from the discharges of local agricultural activities, displayed a significantly higher concentration at an average value of 44.85 μg x m(-3). The average fine sulfate and nitrate oxidation ratios (SOR and NOR) were SOR = 0.60, NOR = 0.30, revealing the remarkable characteristics of secondary pollution. As could be found from the relevant analysis, the NH4(+) of Quzhou showed well relations with NO3(-) and SO4(2-), and the environment here was rich of ammonia. The NH4(+) existed in the form of (NH4)2SO4 and the generation of NO3(-) was limited by the HNO3. From the analysis for the equilibrium of NH4NO3, we observed that the atmospheric environment of Quzhou was adverse to the generation and maintenance of NH4NO3 during the daytime,in contrast with the night. Integrated with the study, the results displayed that the secondary transformation was the main source of fine particles in Quzhou, and the NH3 from field and compost was the significant factor leading to the high value of S-N-A.

Laboratory studies of key gas-phase HOx-NOx coupling reactions.

NASA Astrophysics Data System (ADS)

Dillon, Terry J.; Dulitz, Katrin; Crowley, John N.

2013-04-01

The HOx (OH & HO2) and NOx (NO & NO2) families of atmospheric radicals are coupled via a number of gas-phase reactions. These reactions have a substantial impact by controlling radical propagation / termination in catalytic cycles, so modifying the oxidation power of the atmosphere and its rate of O3 production. However, field measurements {1-3} have demonstrated that our understanding of HOx - NOx chemistry is incomplete. We have identified four reactions (R1-R4) where the database is particularly unsatisfactory, leading to large uncertainties in atmospheric models {4-5}. HO2 + NO -> OH + NO2 (R1a) HO2 + NO (+ M) -> HNO3 (+ M) (R1b) NO2* + H2O -> NO2 + H2O (R2a) NO2* + H2O -> OH + HONO (R2b) NO3* + H2O -> NO3 + H2O (R3a) NO3* + H2O -> OH + HNO3 (R3b) OH + HNO3 -> H2O + NO3 (R4) In this experimental work, laser-based kinetic and spectroscopic tools were used to investigate recent observations {6-7} of HNO3 formation from the (otherwise radical propagating) HO2 + NO (R1), and OH formation following absorption of abundant, long wavelength photons by NO2 {8} and NO3 in the presence of water vapour (R2, R3). Uncertainties {9} associated with a classical HOx-NOx coupling reaction (R4) were also addressed. Critical photochemical parameters so derived have included absolute rate coefficients for (R1) and (R4) and product yields (R1b, R2b, R3b). The atmospheric implications of these results will be discussed. References: {1} Faloona, I. et al. J. Geophys. Res., 105, 3771-3783, 2000.; {2} Thakur, A.N. et al., Atmos. Environ., 33, 1403-1422, 1999.; {3} Wennberg, P.O. et al., Geophys. Res. Lett., 26, 1373-1376, 1999.; {4} Cariolle, D. et al., Atmos. Chem. Phys., 8, 4061-4068, 2008.; {5} Wennberg P.O. and Dabdub, D. Science, 319, 2008. ; {6} Butkovskaya, N. et al., J. Phys. Chem. A, 111, 9047-9053, 2007.; {7} Butkovskaya, N. et al., J. Phys. Chem. A, 109, 6509-6520, 2005.; {8} Li, S.P. et al., Science, 319, 1657-1660, 2008. {9} Brown, S.S. et al., J. Phys. Chem., 103, 3031-3037, 1999.

An Electronic Tongue Designed to Detect Ammonium Nitrate in Aqueous Solutions

PubMed Central

Campos, Inmaculada; Pascual, Lluis; Soto, Juan; Gil-Sánchez, Luis; Martínez-Máñez, Ramón

2013-01-01

An electronic tongue has been developed to monitor the presence of ammonium nitrate in water. It is based on pulse voltammetry and consists of an array of eight working electrodes (Au; Pt; Rh; Ir; Cu; Co; Ag and Ni) encapsulated in a stainless steel cylinder. In a first step the electrochemical response of the different electrodes was studied in the presence of ammonium nitrate in water in order to further design the wave form used in the voltammetric tongue. The response of the electronic tongue was then tested in the presence of a set of 15 common inorganic salts; i.e.; NH4NO3; MgSO4; NH4Cl; NaCl; Na2CO3; (NH4)2SO4; MgCl2; Na3PO4; K2SO4; K2CO3; CaCl2; NaH2PO4; KCl; NaNO3; K2HPO4. A PCA plot showed a fairly good discrimination between ammonium nitrate and the remaining salts studied. In addition Fuzzy Art map analyses determined that the best classification was obtained using the Pt; Co; Cu and Ni electrodes. Moreover; PLS regression allowed the creation of a model to correlate the voltammetric response of the electrodes with concentrations of ammonium nitrate in the presence of potential interferents such as ammonium chloride and sodium nitrate. PMID:24145916

[Characteristics of particulate matters and its chemical compositions during the dust episodes in Shanghai in spring, 2011].

PubMed

Li, Gui-Ling; Zhou, Min; Chen, Chang-Hong; Wang, Hong-Li; Wang, Qian; Lou, Sheng-Rong; Qiao, Li-ping; Tang, Xi-bin; Li, Li; Huang, Hai-ying; Chen, Ming-hua; Huang, Cheng; Zhang, Gang-Feng

2014-05-01

A continuous air quality observation was conducted in the urban area of Shanghai from April 28 to May 18 in 2011. The mass concentration of particle matters and main chemical compositions of fine particle were measured and analyzed. The mass concentrations of PM10 and PM2.5 during the dust episode were much higher than those in non-dust episode, with the maximum daily mass concentrations of PM10 and PM2.5 reaching 787.2 microg.gm-3 and 139.5 microgm(-3) , respectively. The average PM2.5 /PM10 ratio was (32.9 +/-14. 6)% (15. 6% -85.1% ). The total water soluble inorganic ions(TWSII ) contributed (27.2 +/- 19. 2)% (4. 8% -80. 8% ) of total PM2.5, and the secondary water soluble ions (SNA) , including SO(2-)4 , NO-(3) and NH(+)(4) , were (76.9 +/- 13.9)% (41.9%-94.2%) in TWSIl. The concentrations of TWSII and SNA in PM2.5 during dust days became lower than those in non-dust days while the trend of the ratio of Ca2+ to PM2.5, increased. The mean OC/EC value in non-dust days was higher than that in the heavy dust pollution episode, but lower than that in weak dust days. In addition, mineral-rich particle in dust period had an acid-buffer effect, making particle alkaline in dust days stronger. In non-dust days, SO(2-)(4) and NO(-)(3) mainly existed in the form of NH4HSO4, (NH4)SO4, and NH4NO3, and combined with other mineral ions during dust days.

Atmospheric acidity measurements on allegheny mountain and the origins of ambient acidity in the Northeastern United States

NASA Astrophysics Data System (ADS)

Pierson, William R.; Brachaczek, Wanda W.; Gorse, Robert A.; Japar, Steven M.; Norbeck, Joseph M.; Keeler, Gerald J.

Atmospheric acidity as HNO 3(g), SO 2(g), and aerosol H + was measured on Allegheny Mountain and Laurel Hill in southwest Pennsylvania in August 1983. The aerosol H + appeared to represent the net after H 2SO 4 reaction with NH 3(g). The resulting H +/SO 42- ratio depended on SO 42- concentration, approaching that of H 2SO 4 at the highest SO 42- concentrations. The atmosphere was acidic; the average concentrations of HNO 3 (78 nmole m -3) and aerosol H + (205 nmole m -3), NH 4+ (172 nmole m -3) and SO 42- (201 nmole m -3), and the dearth of NH 3(< 15 nmolem -3), show that the proton acidity (HNO 3, H 2SO 4) of the air exceeded the acid-neutralizing capacity of the air by a factor of > 2, with one 10-h period averaging 263 and 844 nmolem -3 for HNO 3 and aerosol H +, respectively. SO 2 added another 900 nmole m -3 (average) of potential H + acidity. HNO 3 and aerosol H + episodes were concurrent, on 7-8 day cycles, unrelated to SO 2 which existed more in short-lived bursts of apparently more local origin. NOx was sporadic like SO 2. Laurel and Allegheny, separated by 35.5 km, were essentially identical in aerosol SO 42-, and in aerosol H +, less so in HNO 3 and especially less so in SO 2; apparently, chemistry involving HNO 3 and aerosol H + or SO 42- was slow compared to inter-site transport times (1-2 h). From growth of bscat and decline of SO 2 during one instance of inter-site transport, daytime rate coefficients for SO 2 oxidation and SO 2 dry deposition were inferred to have been, respectively, ~ 0.05 and ⩽ 0.1 h -1. HNO 3 declined at night. Aerosol H + and SO 42- showed no significant diurnal variation, and O 3 showed very little; these observations, together with high PAN/NO x ratios, indicate that regional transport rather than local chemistry is governing. The O 3 concentration (average 56 ppb or 2178 nmolem -3) connotes an oxidizing atmosphere conducive to acid formation. Highest atmospheric acidity was associated with (1) slow westerly winds traversing westward SO 2 source areas, (2) local stagnation, or (3) regional transport around to the back side of a high pressure system. Low acidity was associated with fast-moving air masses and with winds from the northerly directions; upwind precipitation also played a moderating role in air parcel acidity. Much of the SO 2 and NOx, and ultimately of the HNO 3 and aerosol H +, appeared to originate from coal-fired power plants. An automotive contribution to the NOx and HNO 3 could not be discerned. Size distributions of aerosol H + and SO 42- were alike, with MMED ~ 0.7 μm, in the optimum range for efficient light scattering and inefficient wet/dry removal. Thus, light scattering and visual range degradation were attributable to the acidic SO 42- aerosol, linking the issues of acid deposition and visual air quality in the Northeast. With inefficient removal of aerosol H +, and inefficient night-time removal of HNO 3, strong acids may be capable of long-distance transport in the lower troposphere. We obtained an accounting of aerosol mass in terms of composition, including aerosol H 2O which was shown to account for much of the light scattering.

Case studies on the chemical composition of fogwater: The influence of local gaseous emissions

NASA Astrophysics Data System (ADS)

Johnson, C. Annette; Sigg, Laura; Zobrist, Jürg

In order to study the mechanisms governing the composition of fogwater, sequential samples were taken during two fog events over several hours and analyzed chemically. In addition, preliminary measurements of gases (HCl, HNO 3, NH 3) and aerosols (H 2SO 4, NH 4NO 3, NH 4Cl and ammonium sulfates) were made. The uptake of gaseous HCl in the fog droplets was a major source of acidity: in extreme cases pH values of 2.08 and 1.94 and Cl - concentrations up to 10 -2 M were observed. HCl originated from a local source, most probably a refuse incinerator from which plumes of the stack gas reached the sampling site. The NH +4, NO -3 and SO -24 concentrations (in the range of 0.1-2 mrnol l-1) were regulated by the inputs of aerosols and the liquid water content of the fog. The contribution of dissolved S(IV) (0.06-0.27 mmol l-1) to the total aqueous sulfur varied with time, according to the pH-dependent solubility of SO 2 and to oxidation reactions.

Source regions and transport pathways of PM2.5 at a regional background site in East China

NASA Astrophysics Data System (ADS)

Zhang, Yanru; Zhang, Hongliang; Deng, Junjun; Du, Wenjiao; Hong, Youwei; Xu, Lingling; Qiu, Yuqing; Hong, Zhenyu; Wu, Xin; Ma, Qianli; Yao, Jie; Chen, Jinsheng

2017-10-01

PM2.5 samples were collected daily at the Lin'an regional background station (LA) in Zhejiang, China during 2014-2015 and the major chemical components including organic carbon (OC), elemental carbon (EC) and water-soluble inorganic ions (WSII) were determined. Backward trajectory clustering and potential source contribution function (PSCF) were adopted for identifying the transport pathways and potential source regions of PM2.5 at LA. The annual mean concentration was 68.9 ± 28.3 μg m-3, indicating severe pollution in East China. Obvious seasonal variations were found, with highest level in winter and lowest in summer. Carbonaceous aerosols and WSII were the predominant compositions, accounting for 30.7% and 53.5% of PM2.5, respectively. Secondary inorganic ions (SO42-, NO3-, and NH4+) made a total contribution of 45.2% to PM2.5. Heterogeneous formation played a dominant role in SO42- formation and NH4+ formation promoted NO3- formation. Stationary sources played a more important role than mobile sources based on NO3-/SO42- ratio of 0.53. Aerosol environment at LA was ammonium-poor and SO42- was only neutralized sufficiently by NH4+ with the predominant production of (NH4)2SO4 in winter. Four major transport pathways of air masses at LA were found based on trajectory clustering. Air masses from the northwest Gobi areas passing over the heavily polluted regions in North and Central China had the highest levels of PM2.5, followed by the air masses from Central China. PSCF results suggested that surrounding areas in the Yangtze River Delta region were major regional origins of PM2.5 and its major components. Northern region was an important origin for carbonaceous components, and southwestern region was significant for secondary inorganic ions. This study helps understand PM2.5 characteristics, identify potential source regions and effectively control PM2.5 in East China.

Experimental characterization of enhanced SNCR process with carbonaceous gas additives.

PubMed

Yao, Ting; Duan, Yufeng; Yang, Zhizhong; Li, Yuan; Wang, Linwei; Zhu, Chun; Zhou, Qiang; Zhang, Jun; She, Min; Liu, Meng

2017-06-01

Carbonaceous gases such as CO and alkanes are commonly used as additives to enhance the selective non-catalytic reduction (SNCR) performance due to their high reducibility. This study compared the effect of CO and CH 4 on NO reduction in a tubular reactor with simulated flue gas. The enhancement of C 3 H 8 on SNCR process was tested at extremely low temperature, i.e. 650 °C. Experimental results suggested that reactions between NH 3 and SO 2 were favored at low temperatures and the competition for NH 3 between SO 2 and NO was influenced by gas additives. A maximum downward shift of 25 °C and 100 °C in temperature window for 50% NO reduction efficiency was obtained with the addition of CO and CH 4 , respectively. Considerable CO emission was observed with addition of CH 4 . The addition of CH 4 contributed to the formation of a self-accelerating reaction route within NO/O 2 /NH 3 SNCR reaction system. NO 2 produced from NO accelerates the oxidation of CH 4 to CO, while the oxidation of CH 4 returns to enhance the NO reduction globally. Optimal NO reduction of 44% was achieved with addition of C 3 H 8 at 650 °C. Substantial portion of C 3 H 8 was partially oxidized to CO and the remaining was converted into C 2 H 4 and C 3 H 6 during the SNCR process. Oxidative dehydrogenation of C 3 H 8 was involved. High reactivity of C 3 H 6 and C 2 H 4 favored the further oxidation and cracking to produce CO. These differences in oxidation behavior significantly influence the promotion capacities of CO, CH 4 and C 3 H 8 for NO reduction. Copyright © 2017 Elsevier Ltd. All rights reserved.

Simultaneous removal of NOx and SO2 from flue gas using combined Na2SO3 assisted electrochemical reduction and direct electrochemical reduction.

PubMed

Guo, Qingbin; He, Yi; Sun, Tonghua; Wang, Yalin; Jia, Jinping

2014-07-15

A method combining Na2SO3 assisted electrochemical reduction and direct electrochemical reduction using Fe(II)(EDTA) solution was proposed to simultaneously remove NOx and SO2 from flue gas. Activated carbon was used as catalyst to accelerate the process. This new system features (a) direct conversion of NOx and SO2 to harmless N2 and SO4(2-); (b) fast regeneration of Fe(II)(EDTA); (c) minimum use of chemical reagents; and (d) recovery of the reduction by-product (Na2SO4). Fe(II)(EDTA) solution was continuously recycled and reused during entire process, and no harmful waste was generated. Approximately 99% NOx and 98% SO2 were removed under the optimal condition. The stability test showed that the system operation was reliable. Copyright © 2014 Elsevier B.V. All rights reserved.

Weakly nucleophilic potassium aryltrifluoroborates in palladium-catalyzed Suzuki-Miyaura reactions: relative reactivity of K[4-RC6F4BF3] and the role of silver-assistance in acceleration of transmetallation.

PubMed

Bardin, Vadim V; Shabalin, Anton Yu; Adonin, Nicolay Yu

2015-01-01

Small differences in the reactivity of weakly nucleophilic potassium aryltrifluoroborates are revealed in the silver-assisted Pd-catalyzed cross-coupling of K[4-RC6F4BF3] (R = H, Bu, MeO, EtO, PrO, iPrO, BuO, t-BuO, CH2=CHCH2O, PhCH2O, PhCH2CH2O, PhO, F, pyrazol-1-yl, pyrrol-1-yl, and indol-1-yl) with ArX (4-BrC6H4CH3, 4-IC6H4F and 3-IC6H4F). An assumed role of silver(I) compounds Ag m Y (Y = O, NO3, SO4, BF4, F) consists in polarization of the Pd-X bond in neutral complex ArPdL n X with the generation of the related transition state or formation of [ArPdL n ][XAg m Y] with a highly electrophilic cation and subsequent transmetallation with the weakly nucleophilic borate. Efficiency of Ag m Y as a polarizing agent decreases in order Ag2O > AgNO3 ≈ Ag2SO4 > Ag[BF4] > AgF. No clear correlation between the reactivity of K[4-RC6F4BF3] and substituent electron parameters, σI and σR°, of the aryl group 4-RC6F4 was found.

Weakly nucleophilic potassium aryltrifluoroborates in palladium-catalyzed Suzuki–Miyaura reactions: relative reactivity of K[4-RC6F4BF3] and the role of silver-assistance in acceleration of transmetallation

PubMed Central

Bardin, Vadim V; Shabalin, Anton Yu

2015-01-01

Summary Small differences in the reactivity of weakly nucleophilic potassium aryltrifluoroborates are revealed in the silver-assisted Pd-catalyzed cross-coupling of K[4-RC6F4BF3] (R = H, Bu, MeO, EtO, PrO, iPrO, BuO, t-BuO, CH2=CHCH2O, PhCH2O, PhCH2CH2O, PhO, F, pyrazol-1-yl, pyrrol-1-yl, and indol-1-yl) with ArX (4-BrC6H4CH3, 4-IC6H4F and 3-IC6H4F). An assumed role of silver(I) compounds AgmY (Y = O, NO3, SO4, BF4, F) consists in polarization of the Pd–X bond in neutral complex ArPdLnX with the generation of the related transition state or formation of [ArPdLn][XAgmY] with a highly electrophilic cation and subsequent transmetallation with the weakly nucleophilic borate. Efficiency of AgmY as a polarizing agent decreases in order Ag2O > AgNO3 ≈ Ag2SO4 > Ag[BF4] > AgF. No clear correlation between the reactivity of K[4-RC6F4BF3] and substituent electron parameters, σI and σR°, of the aryl group 4-RC6F4 was found. PMID:26124862

40 CFR Figure C-1 to Subpart C of... - Suggested Format for Reporting Test Results for Methods for SO 2, CO, O 3, NO 2

Code of Federal Regulations, 2013 CFR

2013-07-01

... Results for Methods for SO 2, CO, O 3, NO 2 C Figure C-1 to Subpart C of Part 53 Protection of Environment... Pt. 53, Subpt. C, Fig. C-1 Figure C-1 to Subpart C of Part 53—Suggested Format for Reporting Test... Difference Table C-1 spec. Pass or fail Low 1 ____ pPM 2 to ____ pPM 3 4 5 6 Medium 1 ____ pPM 2 to ____ pPM...

Optimization of submerged fermentation medium for citrinin-free monascin production by Monascus.

PubMed

Chen, Di; Xue, Yuan; Chen, Mianhua; Li, Zhenjing; Wang, Changlu

2016-11-16

Microbial fermentation of citrinin-free Monascus pigments is in favor in the development of food industry. This study investigated the influences of carbon source, nitrogen source, and mineral salts on the cell growth, monascin (MS), and citrinin (CT) production in Monascus M9. A culture medium composition was established for maximizing the production of citrinin-free MS in submerged culture, as follows: 50 g/L Japonica rice powder, 20 g/L NH 4 NO 3 , 3 g/L NaNO 3 , 1.5 g/L KH 2 PO 4 , 1 g/L MgSO 4  · 7H 2 O, 0.2 g/L MnSO 4 . Under these conditions, no CT was detectable by high performance liquid chromatography. The yield of MS reached 14.11 mg/g, improving approximately 30% compared with before optimization.

Synthesis of Potential Prophylactic Agents Against Cyanide Intoxication

DTIC Science & Technology

1993-05-06

34/21) S 2,6-C 2 Ad 72 mp 139" CsH3C12NO 163 (lie mp 139.5-140.5") 6 4-OMe A 45 Mp 73-79e CH 7N0% (lit t mp 73-741) 7 2-OMe A 50 Mp 66" C*HNO 126 (litf...Form. Found cation. Compd. No. Reactants Yield, % Mp, *C (cation.anion) %C %H %N anion Part A. 1 -Alkoxypyridinium salts. 14 2,3-Mes, 87 120-122 CH ...111 + 4(C6H6CVs O, 28.62 3.22 4.40 ..... (MeO)2SO2 _OSO 2 CH s ) is 4-OMe,6 + 78 46-48 CSH 121NO 2 34.18 4.30 4.91 154, 126 Ed (CsH12NO2-) 34.02

SO and SO2 in mass-loss envelopes of red giants: probes of nonequilibrium circumstellar chemistry and mass-loss rates.

PubMed

Sahai, R; Wannier, P G

1992-07-20

We have made a search for SO in the mass-loss envelopes of 24 mostly oxygen-rich red giants, using the 8(8)-7(7) (344.3 GHz), 6(5)-5(4) (219.9 GHz), 4(3)-3(2) (138.2 GHz), and 3(2)-2(1) (99.3 GHz) transitions. One or more of these transitions were detected toward 14 envelopes, including those of the supergiants VY CMa and IRC +10420. The SO envelope of IK Tau was measurably extended, and that of IRC +10420 marginally so, allowing us to determine the envelope sizes directly. The SiO (v = 0) J = 8-7, J = 5-4, and J = 3-2 lines at 347.3, 217.1, and 130.3 GHz were detected simultaneously with the 344.3, 219.9, and 138.2 GHz SO lines, respectively. From our SO data, as well as from SO2 data published elsewhere (for a few sources), we derive the circumstellar SO and SO2 abundances and compare them with theoretical predictions. We find that the photospheric abundances of SO and SO2 are insignificant, and that SO and SO2 must be produced in the circumstellar envelopes. However, the (average) SO abundances are larger than even the peak values predicted by nonequilibrium circumstellar chemistry models. The large SO abundances imply that S is not heavily depleted into grains in these envelopes, and further suggest that (i) the stellar mass-loss rates in these objects are substantially larger than accepted values, (ii) the circumstellar H/H2 abundance ratio is quite small, and (iii) the reaction of O and SH dominates over the reaction of S and OH in the production of SO. In the peculiar bipolar nebula OH 231.8+4.2, the combined SO and SO2 abundance exceeds the cosmic S abundance, if the mass-loss rate in this object is smaller than or equal to l0(-4) M solar yr-1. In IK Tau the data can only be fitted with models in which the SO is distributed in a hollow shell, as predicted by the nonequilibrium chemistry models. In another three, which have no measurable OH, the discovery of SO is difficult to explain by such models.

Responses of soil N-fixing bacteria communities to invasive plant species under different types of simulated acid deposition

NASA Astrophysics Data System (ADS)

Wang, Congyan; Zhou, Jiawei; Jiang, Kun; Liu, Jun; Du, Daolin

2017-06-01

Biological invasions have incurred serious threats to native ecosystems in China, and soil N-fixing bacteria communities (SNB) may play a vital role in the successful plant invasion. Meanwhile, anthropogenic acid deposition is increasing in China, which may modify or upgrade the effects that invasive plant species can cause on SNB. We analyzed the structure and diversity of SNB by means of new generation sequencing technology in soils with different simulated acid deposition (SAD), i.e., different SO4 2- to NO3 - ratios, and where the invasive ( Amaranthus retroflexus L.) and the native species ( Amaranthus tricolor L.) grew mixed or isolated for 3 months. A. retroflexus itself did not exert significant effects on the diversity and richness of SNB but did it under certain SO4 2- to NO3 - ratios. Compared to soils where the native species grew isolated, the soils where the invasive A. retroflexus grew isolated showed lower relative abundance of some SNB classes under certain SAD treatments. Some types of SAD can alter soil nutrient content which in turn could affect SNB diversity and abundance. Specifically, greater SO4 2- to NO3 - ratios tended to have more toxic effects on SNB likely due to the higher exchange capacity of hydroxyl groups (OH-) between SO4 2- and NO3 -. As a conclusion, it can be expected a change in the structure of SNB after A. retroflexus invasion under acid deposition rich in sulfuric acid. This change may create a plant soil feedback favoring future A. retroflexus invasions.

Responses of soil N-fixing bacteria communities to invasive plant species under different types of simulated acid deposition.

PubMed

Wang, Congyan; Zhou, Jiawei; Jiang, Kun; Liu, Jun; Du, Daolin

2017-06-01

Biological invasions have incurred serious threats to native ecosystems in China, and soil N-fixing bacteria communities (SNB) may play a vital role in the successful plant invasion. Meanwhile, anthropogenic acid deposition is increasing in China, which may modify or upgrade the effects that invasive plant species can cause on SNB. We analyzed the structure and diversity of SNB by means of new generation sequencing technology in soils with different simulated acid deposition (SAD), i.e., different SO 4 2- to NO 3 - ratios, and where the invasive (Amaranthus retroflexus L.) and the native species (Amaranthus tricolor L.) grew mixed or isolated for 3 months. A. retroflexus itself did not exert significant effects on the diversity and richness of SNB but did it under certain SO 4 2- to NO 3 - ratios. Compared to soils where the native species grew isolated, the soils where the invasive A. retroflexus grew isolated showed lower relative abundance of some SNB classes under certain SAD treatments. Some types of SAD can alter soil nutrient content which in turn could affect SNB diversity and abundance. Specifically, greater SO 4 2- to NO 3 - ratios tended to have more toxic effects on SNB likely due to the higher exchange capacity of hydroxyl groups (OH - ) between SO 4 2- and NO 3 - . As a conclusion, it can be expected a change in the structure of SNB after A. retroflexus invasion under acid deposition rich in sulfuric acid. This change may create a plant soil feedback favoring future A. retroflexus invasions.

Water-soluble ions in atmospheric aerosols measured in Xi'an, China: Seasonal variations and sources

NASA Astrophysics Data System (ADS)

Zhang, T.; Cao, J. J.; Tie, X. X.; Shen, Z. X.; Liu, S. X.; Ding, H.; Han, Y. M.; Wang, G. H.; Ho, K. F.; Qiang, J.; Li, W. T.

2011-10-01

Daily PM 2.5 and water-soluble inorganic ions (Na +, NH 4+, K +, Mg 2+, Ca 2+, Cl -, NO 3- and SO 42-) were collected in Xi'an (34.23°N, 108.88°E), China from March 2006 to March 2007. PM 2.5 was collected using battery-powered mini-volume samplers. And the ions were determined by ion chromatography from the measured aerosol mass. The annual average mass concentration of PM 2.5 was found to be 194.1 ± 78.6 μg m - 3 , which exceeded substantially the international guidelines for health concerns. The seasonal average mass concentration of PM 2.5 was highest in winter (266.8 μg m - 3 ) and lowest in summer (138.6 μg m - 3 ). The three highest abundant ions were SO 42-, NO 3-, and NH 4+, with average concentrations of 35.6 ± 19.5 μg m - 3 , 16.4 ± 10.1 μg m - 3 , and 11.4 ± 6.8 μg m - 3 , which were accounted for 18.7%, 8.0%, and 5.7% of the PM 2.5 mass, respectively. The major ions were in the species of (NH 4) 2SO 4, NH 4HSO 4 and NH 4NO 3, and their concentrations were highest in winter, due to high coal combustion. The concentrations of Ca 2+ were higher in spring than other seasons, due to the higher mineral dust concentrations. Ca 2+ was strongly correlated with CO 32-, which was calculated as the difference in the measured cations minus anions. Ion balance calculations indicate that the PM 2.5 was acidic, and this result is consistent with the measurement of pH values. Sulfur oxidation ratio was higher in summer and autumn, which implies that the formation of secondary sulfate-rich particles is favored by warm and relatively moist weather. Nitrogen oxidation ratio was highest in autumn.

Aquatic plant-derived changes in oil sands naphthenic acid signatures determined by low-, high- and ultrahigh-resolution mass spectrometry.

PubMed

Headley, John V; Peru, Kerry M; Armstrong, Sarah A; Han, Xiumei; Martin, Jonathan W; Mapolelo, Mmilili M; Smith, Donald F; Rogers, Ryan P; Marshall, Alan G

2009-02-01

Mass spectrometry is a common tool for studying the fate of complex organic compound mixtures in oil sands processed water (OSPW), but a comparison of low-, high- ( approximately 10 000), and ultrahigh-resolution ( approximately 400 000) instrumentation for this purpose has not previously been made. High-resolution quadrupole time-of-flight mass spectrometry (QTOF MS) and ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), with negative-ion electrospray ionization, provided evidence for the selective dissipation of components in OSPW. Dissipation of oil sands naphthenic acids (NAs with general formula C(n)H(2n+z)O(2) where n is the number of carbon atoms, and Z is zero or a negative even number describing the number of rings) was masked (by components such as fatty acids, O(3), O(5), O(6), O(7), SO(2), SO(3), SO(4), SO(5), SO(6), and NO(4) species) at low resolution (1000) when using a triple quadrupole mass spectrometer. Changes observed in the relative composition of components in OSPW appear to be due primarily to the presence of plants, specifically cattails (Typha latifolia) and their associated microorganisms. The observed dissipation included a range of heteratomic species containing O(2), O(3), O(4), and O(5), present in Athabasca oil sands acid extracts. For the heteratomic O(2) species, namely naphthenic acids, an interesting structural relationship suggests that low and high carbon number NAs are dissipated by the plants preferentially, with a minimum around C(14)/C(15). Other heteratomic species containing O(6), O(7), SO(2), SO(3), SO(4), SO(5), SO(6), and NO(4) appear to be relatively recalcitrant to the cattails and were not dissipated to the same extent in planted systems. Copyright 2009 John Wiley & Sons, Ltd.

Matrix influences on the determination of common ions by using ion chromatography part 1--determination of inorganic anions.

PubMed

Michalski, Rajmund; Lyko, Aleksandra; Kurzyca, Iwona

2012-07-01

Ion chromatography is the most popular instrumental analytical method used for the determination of anions and cations in water and wastewater. Isocratic ion chromatography with suppressed conductivity detection is frequently used in laboratories carrying out routine analyses of inorganic anions. The paper presents the results of the research into the influence of selected inorganic anions dominant in environmental samples (Cl(-), NO(3)(-), SO(4)(2-)) on the possibility of simultaneous determination of F(-), Cl(-), NO(2)(-), NO(3)(-), PO(4)(3-) and SO(4)(2-) with the application of this most popular ion chromatography type in standard separation conditions. Four Dionex and four Metrohm anion-exchange columns were tested in standard separation conditions recommended by their manufacturers with both standard solutions and environmental samples with complex matrix.

The impacts of anthropogenic emissions on the precipitation chemistry at an elevated site in North-eastern China

NASA Astrophysics Data System (ADS)

Wang, Yan; Wai, Ka Ming; Gao, Jian; Liu, Xiaohuan; Wang, Tao; Wang, Wenxing

Ninety precipitation samples were collected from 2004 to 2006 at the summit of the Mt. Tai in order to detect the impacts of regional sources of pollution on precipitation chemistry in the highly polluted North China Plains. The annual volume-weighted pH of the precipitation was found to be 4.7, in contrast to the less-acidic nature (pH>5.6) of precipitation in northern China reported in many past studies. Non-sea-salt (nss)-SO 42- (131.5 μeq L -1), NH 4+ (82.2 μeq L -1) and Ca 2+ (61.4 μeq L -1) were the most abundant species in precipitation. The wide range of the Cl -/Na + ratios (0.2-5.4) in precipitation implied the co-existence of Cl - enrichment and depletion. The nss-SO 42-, NO 3-, NH 4+, Ca 2+ and K + concentrations peaked in spring, but with the lowest acidity. The very strong correlations of Ca 2+ with nss-SO 42- and NO 3- suggested a significant uptake of nss-SO 42- and NO 3- on dust aerosol during spring. Samples with the lowest pH value (4.5) are associated with the stagnant air conditions. The nss-SO 42- and NH 4+ concentrations at Mt. Tai were the highest compared with those at the EANET, NADP and EMEP sites of similar elevations. With relatively high rainfall amount measured at our site, the high wet deposition of the major acidic/alkaline species exerted large loadings to the ecosystem. The associated impacts on agriculture, soil and aquatic systems should be investigated.

Effect of nitrate on uptake of pertechnetate by tomato plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krijger, G.C.; Kolloeffel, C.; Wolterbeek, H.T.

Nitrate has been shown to affect the acquisition of the nuclear waste product technetium (Tc) by plants. The mechanism responsible for this phenomenon is unknown. The uptake of [{sup 99m}Tc]TcO{sub 4}{sup {minus}},[{sup 35}S] SO{sub 4}{sup 2{minus}} and H{sub 2}[{sup 32P}]PO{sub 4}{sup {minus}} was studied in tomato plants (Lycopersicon esculentum Mill., cv. Tiny Tim) with different growth rates due to culture at 0.5, 4.0, or 30 mM NO{sub 3}{sup {minus}}. In experiments lasting 24 h, net TcO{sub 4}{sup {minus}} uptake decreased at higher NO{sub 3}{sup {minus}} supplies. The inhibitory effect of NO{sub 3}{sup {minus}} on TcO{sub 4}{sup {minus}} uptake also wasmore » shown in TcO{sub 4}{sup {minus}} influx experiments (K{sub i} = 3.3 mM), although about 30% of the TcO{sub 4}{sup {minus}} influx is suggested to be insensitive to NO{sub 3}{sup {minus}}. In contrast, H{sub 2}PO{sub 4}{sup {minus}} (30 mM) did not inhibit TcO{sub 4}{sup {minus}} influx, whereas SO{sub 4}{sup 2{minus}} (30 mM) tended to increase TcO{sub 4}{sup {minus}} influx, probably due to the ionic strength of the uptake solution. Significant effects of the NO{sub 3}{sup {minus}} supply on Tc efflux were not found. Overall, this leads to the conclusion that TcO{sub 4}{sup {minus}} and NO{sub 3}{sup {minus}} share at least one transporter.« less

Structural and kinetic study of reversible CO2 fixation by dicopper macrocyclic complexes. From intramolecular binding to self-assembly of molecular boxes.

PubMed

Company, Anna; Jee, Joo-Eun; Ribas, Xavi; Lopez-Valbuena, Josep Maria; Gómez, Laura; Corbella, Montserrat; Llobet, Antoni; Mahía, José; Benet-Buchholz, Jordi; Costas, Miquel; van Eldik, Rudi

2007-10-29

A study of the reversible CO2 fixation by a series of macrocyclic dicopper complexes is described. The dicopper macrocyclic complexes [Cu2(OH)2(Me2p)](CF3SO3)2, 1(CF3SO3)2, and [Cu2(mu-OH)2(Me2m)](CF3SO3)2, 2(CF3SO3)2, (Scheme 1) containing terminally bound and bridging hydroxide ligands, respectively, promote reversible inter- and intramolecular CO2 fixation that results in the formation of the carbonate complexes [{Cu2(Me2p)}2(mu-CO3)2](CF3SO3)4, 4(CF3SO3)4, and [Cu2(mu-CO3)(Me2m)](CF3SO3)2, 5(CF3SO3)2. Under a N2 atmosphere the complexes evolve CO2 and revert to the starting hydroxo complexes 1(CF3SO3)2 and 2(CF3SO3)2, a reaction the rate of which linearly depends on [H2O]. In the presence of water, attempts to crystallize 5(CF3SO3)2 afford [{Cu2(Me2m)(H2O)}2(mu-CO3)2](CF3SO3)4, 6(CF3SO3)4, which appears to rapidly convert to 5(CF3SO3)2 in acetonitrile solution. [Cu2(OH)2(H3m)]2+, 7, which contains a larger macrocyclic ligand, irreversibly reacts with atmospheric CO2 to generate cagelike [{Cu2(H3m)}2(mu-CO3)2](ClO4)4, 8(ClO4)4. However, addition of 1 equiv of HClO4 per Cu generates [Cu2(H3m)(CH3CN)4]4+ (3), and subsequent addition of Et3N under air reassembles 8. The carbonate complexes 4(CF3SO3)4, 5(CF3SO3)2, 6(CF3SO3)4, and 8(ClO4)4 have been characterized in the solid state by X-ray crystallography. This analysis reveals that 4(CF3SO3)4, 6(CF3SO3)4, and 8(ClO4)4 consist of self-assembled molecular boxes containing two macrocyclic dicopper complexes, bridged by CO32- ligands. The bridging mode of the carbonate ligand is anti-anti-mu-eta1:eta1 in 4(CF3SO3)4, anti-anti-mu-eta2:eta1 in 6(CF3SO3)4 and anti-anti-mu-eta2:eta2 in 5(CF3SO3)2 and 8(ClO4)4. Magnetic susceptibility measurements on 4(CF3SO3)4, 6(CF3SO3)4, and 8(ClO4)4 indicate that the carbonate ligands mediate antiferromagnetic coupling between each pair of bridged CuII ions (J = -23.1, -108.3, and -163.4 cm-1, respectively, H = -JS1S2). Detailed kinetic analyses of the reaction between carbon dioxide and the macrocyclic complexes 1(CF3SO3)2 and 2(CF3SO3)2 suggest that it is actually hydrogen carbonate formed in aqueous solution on dissolving CO2 that is responsible for the observed formation of the different carbonate complexes controlled by the binding mode of the hydroxy ligands. This study shows that CO2 fixation can be used as an on/off switch for the reversible self-assembly of supramolecular structures based on macrocyclic dicopper complexes.

[Characteristics of aerosol water-soluble inorganic ions in three types air-pollution incidents of Nanjing City].

PubMed

Zhang, Qiu-Chen; Zhu, Bin; Su, Ji-Feng; Wang, Hong-Lei

2012-06-01

In order to compare aerosol water-soluble inorganic species in different air-pollution periods, samples of PM10, PM2.1, PM1.1 and the main water-soluble ions (NH4+, Mg2+, Ca2+, Na+, K+, NO2(-), F(-), NO3(-), Cl(-), SO4(2-)) were measured, which were from 3 air-pollution incidents (continued pollution in October 16-30 of 2009, sandstorm pollution in April 27-30 of 2010, and crop burning pollution in June 14 of 2010. The results show that aerosol pollution of 3 periods is serious. The lowest PM2.1/PM10 is only 0.27, which is from sandstorm pollution period, while the largest is 0. 7 from crop burning pollution period. In continued pollution periods, NO3(-) and SO4(2-) are the dominant ions, and the total anions account for an average of 18.62%, 32.92% and 33.53% of PM10, PM2.1 and PM1.1. Total water-soluble ions only account for 13.36%, 23.72% and 28.54% of PM10, PM2.1 and PM1.1 due to the insoluble species is increased in sandstorm pollution period. The mass concentration of Ca2+ in sandstorm pollution period is higher than the other two pollution periods, and which is mainly in coarse particles with diameter larger than 1 microm. All the ten water-soluble ions are much higher in crop burning pollution especially K+ which is the tracer from crop burning. The peak mass concentrations of NO3(-), SO4(2-) and NH4+ are in 0.43-0.65 microm.

The influence of SO4 and NO3 to the acidity (pH) of rainwater using minimum variance quadratic unbiased estimation (MIVQUE) and maximum likelihood methods

NASA Astrophysics Data System (ADS)

Dilla, Shintia Ulfa; Andriyana, Yudhie; Sudartianto

2017-03-01

Acid rain causes many bad effects in life. It is formed by two strong acids, sulfuric acid (H2SO4) and nitric acid (HNO3), where sulfuric acid is derived from SO2 and nitric acid from NOx {x=1,2}. The purpose of the research is to find out the influence of So4 and NO3 levels contained in the rain to the acidity (pH) of rainwater. The data are incomplete panel data with two-way error component model. The panel data is a collection of some of the observations that observed from time to time. It is said incomplete if each individual has a different amount of observation. The model used in this research is in the form of random effects model (REM). Minimum variance quadratic unbiased estimation (MIVQUE) is used to estimate the variance error components, while maximum likelihood estimation is used to estimate the parameters. As a result, we obtain the following model: Ŷ* = 0.41276446 - 0.00107302X1 + 0.00215470X2.

Low-temperature co-purification of NO x and Hg0 from simulated flue gas by Ce x Zr y Mn z O2/r-Al2O3: the performance and its mechanism.

PubMed

Lu, Pei; Yue, Huifang; Xing, Yi; Wei, Jianjun; Zeng, Zheng; Li, Rui; Wu, Wanrong

2018-05-11

In this study, series of Ce x Zr y Mn z O 2 /r-Al 2 O 3 catalysts were prepared by impregnation method and explored to co-purification of NO x and Hg 0 at low temperature. The physical and chemical properties of the catalysts were investigated by XRD, BET, FTIR, NH 3 -TPD, H 2 -TPR, and XPS. The experimental results showed that 10% Ce 0.2 Zr 0.3 Mn 0.5 O 2 /r-Al 2 O 3 yielded higher conversion on co-purification of NO x and Hg 0 than the other prepared catalysts at low temperature, especially at 200-300 °C. 91% and 97% convert rate of NO x and Hg 0 were obtained, respectively, when 10% Ce 0.2 Zr 0.3 Mn 0.5 O 2 /r-Al 2 O 3 catalyst was used at 250 °C. Moreover, the presence of H 2 O slightly decreased the removal of NO x and Hg 0 owing to the competitive adsorption of H 2 O and Hg 0 . When SO 2 was added, the removal of Hg 0 first increased slightly and then presented a decrease due to the generation of SO 3 and (NH 4 ) 2 SO 4 . The results of NH 3 -TPD indicated that the strong acid of 10% Ce 0.2 Zr 0.3 Mn 0.5 O 2 /r-Al 2 O 3 improved its high-temperature activity. XPS and H 2 -TPR results showed there were high-valence Mn and Ce species in 10% Ce 0.2 Zr 0.3 Mn 0.5 O 2 /r-Al 2 O 3 , which could effectively promote the removal of NO x and Hg 0 . Therefore, the mechanisms of Hg 0 and NO x removal were proposed as Hg (ad) + [O] → HgO (ad), and 2NH 3 /NH 4 + (ad) + NO 2 (ad) + NO (g) → 2 N 2  + 3H 2 O/2H + , respectively. Graphical abstract ᅟ.

ACTION OF $gamma$-RAYS ON AQUEOUS SOLUTIONS OF CARBON MONOXIDE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raef, Y.; Swallow, A.J.

1963-07-01

Solutions of CO (4.84 x 10/sup -4/ M) in 0.1 N H/sub 2/SO/sub 4/ (oxygenfree) were irradiated with gamma rays ( approximates 30,000 rad/h) and found to give H with G = 0.95, CO/sub 2/ G = 2.6, formaldehyde G = 0.5, glyoxal G = 0.3, and formic acid G = 0.4. Hydrogen peroxid could not be detected. The results are interpreted in term of a mechanism involving CHO and COOH radicals, some of the products being secondary. The effect of variations in acidity were investigated, a striking observation being that formic acid is produced with G = 44 inmore » alkaline solution. In the presence of ferrous ions (2 x 10/sup -1/ 2 x 10/ sup -9/ M Fe/sup 2+/ 0.1 N H/sub 2/SO/sub 4/ no ferric was produced, but in the presence of ferric ions (2 x 10/sup -4/ 1 x 10/sup -9/ M Fe/sup 3+/, 0.1 N H/sub 2/SO/sub 4/) ferrous ions are produced with G = 8.3--8.4. The ratio of the rate constants for the reactions H + HCHO to H + CO ( in 0.1 N H/sub 2/ SO/sup 4/ is 14.8 plus or minus 3, of OH + CO to OH + Fe/sup 21/ (in 0.1 N H/sub 2/SO/sub 4/ ) is 8.8 plus or minus 0.5, and of H + CO to H + H/sup +/ + Fe/sup 21/ (in 0.1 N H/sub 2/SO /sub 4/ is 2.2 plus or minus 0.3, all at 23 deg C. (auth)« less

High Selective Gas Detection for small molecules based on Germanium selenide monolayer

NASA Astrophysics Data System (ADS)

Liu, Lian; Yang, Qun; Wang, Zeping; Ye, Huaiyu; Chen, Xianping; Fan, Xuejun; Zhang, Guoqi

2018-03-01

Predictive calculations based on density functional theory (DFT) are used here to study the electronic and optical properties of GeSe monolayer after adsorbing gas molecules (O2, NH3, SO2, H2, CO2, H2S, NO2, CH4, H2O, NO, CO). Our results reveal that for all the gas molecules considered, only NH3 is adsorbed on GeSe monolayer by physisorption. Whereas SO2 and NO2 are chemisorbed on GeSe monolayer with strong adsorption energies. In addition, the adsorption of O2, NO and NO2 distinctly enhances the optical absorbance and broaden the absorbance range of GeSe monolayer in visible light region. Also, it is found that the adsorption of H2S, NO and NH3 can reduce the work function of the GeSe monolayer. The results indicate that GeSe monolayer is not only a promising candidate for the sensing, capture, and storage of NH3, but also an anticipated disposable gas sensor or metal-free catalyst for detecting and catalyzing SO2 and NO2. Furthermore, it has excellent potential to be applied to optical sensors, solar cells, nanoelectronics or optoelectronics devices.

A modified SINTACS method for groundwater vulnerability and pollution risk assessment in highly anthropized regions based on NO3- and SO42- concentrations.

PubMed

Busico, Gianluigi; Kazakis, Nerantzis; Colombani, Nicolò; Mastrocicco, Micòl; Voudouris, Konstantinos; Tedesco, Dario

2017-12-31

Groundwater vulnerability and risk assessment are worldwide tools in supporting groundwater protection and land planning. In this study, we used three of these different methodologies applied to the Campanian Plain located in southern Italy: SINTACS, AVI and LOS. However, their capability to describe the observed chemical pollution of the area has resulted quite poor. For such a reason, a modified SINTACS method has been then implemented in the area in order to get a more reliable view of groundwater vulnerability. NO 3 - and SO 4 2- from more than 400 monitoring wells were used for specific vulnerability assessment. Land use was chosen as key parameter to infer the risk of groundwater pollution in our area. The new methodology seems to show a higher correlation with observed NO 3 - concentrations and a more reliable identification of aquifer's pollution hot spots. The main sources of NO 3 - were found in sub-urban areas, where vulnerability and risk are higher than in other areas. Otherwise due to reducing conditions triggered by the presence of elevated sedimentary organic matter and peat, concentrations below agricultural areas were lower than in sub-urban areas. The SO 4 2- specific vulnerability map showed a positive correlation with observed concentrations, due to geogenic and anthropogenic SO 4 2- sources present in the area. The combination of both NO 3 - and SO 4 2- derived risk maps becomes essential to improve the conceptual model of aquifer pollution in this severely anthropized area. The application of this new and original approach shed light on the strengths and weaknesses of each of the described previous methods and clearly showed how anthropogenic activities have to be taken into account in the assessment process. Copyright © 2017 Elsevier B.V. All rights reserved.

Geochemical evolution of groundwater in the Western Delta region of River Godavari, Andhra Pradesh, India

NASA Astrophysics Data System (ADS)

Nageswara Rao, P. V.; Appa Rao, S.; Subba Rao, N.

2017-05-01

The present study on geochemical evolution of groundwater is taken up to assess the controlling processes of water chemistry in the Western Delta region of the River Godavari (Andhra Pradesh), which is one of the major rice-producing centers in India. The study region is underlain by coarse sand with black clay (buried channels), black silty clay of recent origin (floodplain) and gray/white fine sand of modern beach sediment of marine source (coastal zone), including brown silty clay with fine sand (paleo-beach ridges). Groundwater is mostly brackish and very hard. It is characterized by Na+ > Mg2+ > Ca2+:HCO3 - > Cl- > SO4 2- > NO3 -, Na+ > Mg2+ > Ca2+:Cl- > HCO3 - > SO4 2-, and Mg2+ > Na+ > Ca2+ > or < K+:HCO3 - > Cl- > or > SO4 2- facies. The ionic relations (Ca2+ + Mg2+:HCO3 -, Ca2+ + Mg2+:SO4 2- + HCO3 -, Na+ + K+:TC, Na+ + K+:Cl- + SO4 2-, HCO3 -:TC, HCO3 -:Ca2+ + Mg2+, Na+:Cl- and Na+:Ca2+) indicate that the rock weathering, mineral dissolution, evaporation and ion exchange are the processes to control the aquifer chemistry. Anthropogenic and marine sources are also the supplementary factors for brackish water quality. These observations are further supported by Gibbs mechanisms that control the water chemistry. Thus, the study suggests that the initial quality of groundwater of geogenic origin has been subsequently modified by the influences of anthropogenic and marine sources.

The Bear Brook Watershed, Maine (BBWM), USA

USGS Publications Warehouse

Norton, S.; Kahl, J.; Fernandez, I.; Haines, T.; Rustad, L.; Nodvin, S.; Scofield, J.; Strickland, T.; Erickson, H.; Wigington, P.; Lee, J.

1999-01-01

The Bear Brook Watershed Manipulation project in Maine is a paired calibrated watershed study funded by the U.S. EPA. The research program is evaluating whole ecosystem response to elevated inputs of acidifying chemicals. The consists of a 2.5 year calibration period (1987-1989), nine years of chemical additions of (NH4)2SO4 (15N- and 34S-enriched for several years) to West Bear watershed (1989-1998), followed by a recovery period. The other watershed, East Bear, serves as a reference. Dosing is in six equal treatments/yr of 1800 eq SO4 and NH4/ha/yr, a 200% increase over 1988 loading (wet plus dry) for SO4 300% for N (wet NO3 + NH4). The experimental and reference watersheds are forested with mixed hard- and softwoods, and have thin acidic soils, areas of 10.2 and 10.7 ha and relief of 210 m. Thin till of variable composition is underlain by metasedimentary pelitic rocks and calc-silicate gneiss intruded by granite dikes and sills. For the period 1987-1995, precipitation averaged 1.4 m/yr, had a mean pH of 4.5, with SO4, NO3, and NH4 concentrations of 26, 14, and 7 ??eq/L, respectively. The nearly perrenial streams draining each watershed have discharges ranging from 0 (East Bear stops flowing for one to two months per year) to 150 L/sec. Prior to manipulation, East Bear and West Bear had a volume weighted annual mean pH of approximately 5.4, alkalinity = 0 to 4 ??eq/L, total base cations = 184 ??eq/L (sea-salt corrected = 118 ??eq/L), and SO4 = 100 to 111 ??eq/L. Nitrate ranged from 0 to 30 ??eq/L with an annual mean of 6 to 25 ??eq/L; dissolved organic carbon (DOC) ranged from 1 to 7 mg/L but was typically less than 3. Episodic acidification occurred at high discharge and was caused by dilution of cations, slightly increased DOC, significantly higher NO3, and the sea-salt effect. Depressions in pH were accompanied by increases in inorganic Al. The West Bear catchment responded to the chemical additions with increased export of base cations, Al, SO4, NO3, and decreased pH, ANC, and DOC. Silica remained relatively constant. Neutralization of the acidifying chemicals occurred dominantly by cation desorption and mobilization of Al.

An Experimental Study of Atmospheric Homogeneous Nucleation: Cluster Growth and Gas-Particle Reactions of H2SO4

NASA Technical Reports Server (NTRS)

Eisele, F. L.

1996-01-01

The work proposed on this project included both field and laboratory studies. The laboratory studies were to consist of measurements of H2SO4 uptake and evaporation from aerosols of varying chemical composition, while the field component would include measurements of H2SO4 and other compounds which would be conducted as part of a large field campaign. By chance, the opportunity to conduct such an H2SO4/aerosol/ultrafine particle study in conjunction with an OH intercomparison/photochemistry study became available very early in this project (September 1993). This study was conducted at Caribou, Colorado in conjunction with several other groups from NCAR, NOAA and a number of universities. Our group measured OH, H2SO4, SO2, and H20, while Dr. McMurfy's group measured ultrafine particles, and total particle number and size distribution. In addition measurements of HO2/RO2, O3, NO, NO2, NO(y) CO, hydrocarbons, CH2O, and other chemical compounds and meteorological parameters were performed by the other participants and a new laser oblation/mass spectrometry technique was also employed by the NOAA Aeronomy Laboratory to study aerosol composition. The study of aerosol production and growth in conjunction with photochemical measurements is highly advantageous because particle growth precursors such as H2SO4.or MSA are formed by OH initiated sulfur oxidation. The large number of hydrocarbon measurements included in this study were also important in understanding particle growth.

Water-dissolvable sodium sulfate nanowires as a versatile template for the fabrication of polyelectrolyte- and metal-based nanotubes.

PubMed

Pu, Ying-Chih; Hwu, Jih Ru; Su, Wu-Chou; Shieh, Dar-Bin; Tzeng, Yonhua; Yeh, Chen-Sheng

2006-09-06

This study presents the synthesis of water-dissolvable sodium sulfate nanowires, where Na(2)SO(4) nanowires were produced by an easy reflux process in an organic solvent, N,N-dimethylformamide (DMF) and formed from the coexistence of AgNO(3), SnCl(2), dodecylsodium sulfate (SDS), and cetyltrimethylammonium bromide (CTAB). Na(2)SO(4) nanowires were derived from SDS, and the morphology control of the Na(2)SO(4) nanowires was established by the cooperative effects of Sn and NO(3)(-), while CTAB served as the template and led to homogeneous nanowires with a smooth surface. Since the as-synthesized sodium sulfate nanowires are readily dissolved in water, these nanowires can be treated as soft templates for the fabrication of nanotubes by removing the Na(2)SO(4) core. This process is therefore significantly better than other reported methodologies to remove the templates under harsh condition. We have demonstrated the preparation of biocompatible polyelectrolyte (PE) nanotubes using a layer-by-layer (LbL) method on the Na(2)SO(4) nanowires and the formation of Au nanotubes by the self-assembly of Au nanoparticles. In both nanotube synthesis processes, PEI (polyethylenimine), PAA (poly(acrylic acid)), and Au nanoparticles served as the building blocks on the Na(2)SO(4) templates, which were then rinsed with water to remove the core templates. This unique water-dissolvable template is anticipated to bring about versatile and flexible downstream applications.

Short-term temperature impact on simultaneous biological nitrogen-sulphur treatment in EGSB reactor.

PubMed

Sposob, Michal; Dinamarca, Carlos; Bakke, Rune

2016-10-01

Sulphides are present in many wastewater streams; their removal is important due to corrosiveness, toxicity and unpleasant odour, and can be carried out by anaerobic biological treatment. This study focuses on the temperature effect (25-10 °C) on an expanded granular sludge bed (EGSB) reactor for sulphide removal using nitrate as electron acceptor. The reactor was run at a NO 3 - /HS - molar ratio of 0.35 and pH of 8.5-9.0. Samples were analysed by ion chromatography (NO 3 - , SO 4 2- and S 2 O 3 2- ), spectrophotometry (S 2- ) and by scanning electron microscopy (SEM). S 2- and NO 3 - removal was 99.74 ± 0.04 and 99.5 ± 2.9%, respectively. Sulphur (S 0 ) was found on the outer granule surface and struvite inside the granule, by SEM. Sulphide conversion to sulphur was up to 76%. Temperature transitions and levels influenced S 2 O 3 2- and SO 4 2- concentrations.

Chemical Characteristics of Water-Soluble Ions in Particulate Matter in Three Metropolitan Areas in the North China Plain

PubMed Central

Dao, Xu; Wang, Zhen; Lv, Yibing; Teng, Enjiang; Zhang, Linlin; Wang, Chao

2014-01-01

PM2.5 and PM10 samples were collected simultaneously in each season in Beijing, Tianjin and Shijiazhuang to identify the characteristics of water-soluble ion compositions in the North China Plain. The water-soluble ions displayed significant seasonal variation. The dominant ions were NO3 −, SO4 2−, NH4 + and Cl−, accounting for more than 90% and 86% to the mass of total water-soluble ions in PM2.5 and PM10, respectively. The anion/cation ratio indicated that the ion acidity of each city varied both between sites and seasonally. Over 50% of the ion species were enriched in small particles ≤1 µm in diameter. The [NO3 −]/[SO4 2−] ratio indicated that vehicles accounted for the majority of the particulate pollution in Beijing. Shijiazhuang, a city highly reliant on coal combustion, had a higher SO4 2− concentration. PMID:25437210

Effect of nitrate and sulfate relative abundance in PM2.5 on liquid water content explored through half-hourly observations of inorganic soluble aerosols at a polluted receptor site

NASA Astrophysics Data System (ADS)

Xue, Jian; Griffith, Stephen M.; Yu, Xin; Lau, Alexis K. H.; Yu, Jian Zhen

2014-12-01

Liquid water content (LWC) is the amount of liquid water on aerosols. It contributes to visibility degradation, provides a surface for gas condensation, and acts as a medium for heterogeneous gas/particle reactions. In this study, 520 half-hourly measurements of ionic chemical composition in PM2.5 at a receptor site in Hong Kong are used to investigate the dependence of LWC on ionic chemical composition, particularly on the relative abundance of sulfate and nitrate. LWC was estimated using a thermodynamic model (AIM-III). Within this data set of PM2.5 ionic compositions, LWC was highly correlated with the multivariate combination of sulfate and nitrate concentrations and RH (R2 = 0.90). The empirical linear regression result indicates that LWC is more sensitive to nitrate mass than sulfate. During a nitrate episode, the highest LWC (80.6 ± 17.9 μg m-3) was observed and the level was 70% higher than that during a sulfate episode despite a similar ionic PM2.5 mass concentration. A series of sensitivity tests were conducted to study LWC change as a function of the relative nitrate and sulfate abundance, the trend of which is expected to shift to more nitrate in China as a result of SO2 reduction and increase in NOx emission. Starting from a base case that uses the average of measured PM2.5 ionic chemical composition (63% SO42-, 11% NO3-, 19% NH4+, and 7% other ions) and an ionic equivalence ratio, [NH4+]/(2[SO42-] + [NO3-]), set constant to 0.72, the results show LWC would increase by 204% at RH = 40% when 50% of the SO42- is replaced by NO3- mass concentration. This is largely due to inhibition of (NH4)3H(SO4)2 crystallization while PM2.5 ionic species persist in the aqueous phase. At RH = 90%, LWC would increase by 12% when 50% of the SO42- is replaced by NO3- mass concentration. The results of this study highlight the important implications to aerosol chemistry and visibility degradation associated with LWC as a result of a shift in PM2.5 ionic chemical composition to more nitrate in atmospheric environments as is expected in many Chinese cities.

The H2SO4-HNO3-NH3 system at high humidities and in fogs: 1. Spatial and temporal patterns in the San Joaquin Valley of California

NASA Astrophysics Data System (ADS)

Jacob, Daniel J.; Munger, J. William; Waldman, Jed M.; Hoffmann, Michael R.

1986-01-01

A systematic characterization of the atmospheric H2SO4-HNO3-NH3 system was conducted in the fog water, the aerosol, and the gas phase at a network of sites in the San Joaquin Valley of California. Spatial patterns of concentrations were established that reflect the distribution of SO2, NOx, and NH3 emissions within the valley. The concept of atmospheric alkalinity was introduced to interpret these concentrations in terms of the buffering capacity of the atmosphere with respect to inputs of strong acids. Regions of predominantly acidic and alkaline fog water were identified. Fog water was found to be alkaline in most of the valley, but small changes in emission budgets could lead to widespread acid fog. An extended stagnation episode was studied in detail: progressive accumulation of H2SO4-HNO3-NH3 species was documented over the course of the episode and interpreted in terms of production and removal mechanisms. Secondary production of strong acids H2SO4 and HNO3 under stagnant conditions resulted in a complete titration of available alkalinity at the sites farthest from NH3 sources. A steady SO2 conversion rate of 0.4-1.1% h-1 was estimated in the stagnant mixed layer under overcast conditions and was attributed to nonphotochemical heterogeneous processes. Removal of SO2 was enhanced in fog, compared to nonfoggy conditions. Conversion of NOx to HNO3 slowed down during the stagnation episode because of reduced photochemical activity; fog did not appear to enhance conversion of NOx. Decreases in total HNO3 concentrations were observed upon acidification of the atmosphere and were attributed to displacement of NO3- by H2SO4 in the aerosol, followed by rapid deposition of HNO3(g). The occurrence of fog was associated with general decreases of aerosol concentrations due to enhanced removal by deposition.

Challenges in the Search for Magnetic Coupling in 3d/4f Materials: Syntheses, Structures, and Magnetic Properties of the Lanthanide Copper Heterobimetallic Compounds, RE 2 Cu(TeO 3 ) 2 (SO 4 ) 2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, Jian; Chai, Ping; Diefenbach, Kariem

2014-03-03

Twelve new lanthanide copper heterobimetallic compounds, RE2Cu(TeO3)2(SO4)2 (RE = Y, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu), with two different structural topologies, have been prepared by hydrothermal treatment. Both structure types crystallize in the triclinic space group, Pmore » $$\\bar{1}$$, but the unit cell parameters and structures are quite different. The earlier RE2Cu(TeO3)2(SO4)2 (RE = Y, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, and Tm) share a common structural motif consisting of edge-sharing LnO8 chains and [Cu(TeO3)2(SO4)2]6– units. The later lanthanide version (Yb and Lu) is composed of edge-sharing LnO7 dimers bridged by similar [Cu(TeO3)2(SO4)2]6– units. The change in the structure type can be attributed to the decreasing ionic radii of the lanthanides. The compounds containing RE3+ ions with diamagnetic ground states (Y3+ and Eu3+) exhibit antiferromagnetic ordering at 12.5 K and 15 K, respectively, owing to the magnetic exchange between Cu2+ moments. No magnetic phase transition was observed in all the other phases. The lack of magnetic ordering is attributed to the competing magnetic interactions caused by the presence of paramagnetic RE3+ ions. The magnetism data suggests that substantial 3d–4f coupling only occurs in the Yb analogue.« less

Chronic obstructive pulmonary diseases related to outdoor PM10, O3, SO2, and NO2 in a heavily polluted megacity of Iran.

PubMed

Khaniabadi, Yusef Omidi; Daryanoosh, Mohammad; Sicard, Pierre; Takdastan, Afshin; Hopke, Philip K; Esmaeili, Shirin; De Marco, Alessandra; Rashidi, Rajab

2018-04-18

This study was conducted to quantify, by an approach proposed by the World Health Organization (WHO), the daily hospital admissions for chronic obstructive pulmonary disease (COPD) related to exposure to particulate matter (PM 10 ) and oxidants such as ozone (O 3 ), sulfur dioxide (SO 2 ), and nitrogen dioxide (NO 2 ) in a heavily polluted city in Iran. For the health impact assessment, in terms of COPD, the current published relative risk (RR) and baseline incidence (BI) values, suggested by the WHO, and the 1-h O 3 concentrations and daily PM 10 , NO 2 , and SO 2 concentrations were compiled. The results showed that 5.9, 4.1, 1.2, and 1.9% of the COPD daily hospitalizations in 2011 and 6.6, 1.9, 2.3, and 2.1% in 2012 were attributed to PM 10 , O 3 , SO 2 , and NO 2 concentrations exceeding 10 μg/m 3 , respectively. This study indicates that air quality and the high air pollutant levels have an effect on COPD morbidity. Air pollution is associated with visits to emergency services and hospital admissions. A lower relative risk can be achieved if some stringent control strategies for reducing air pollutants or emission precursors are implemented.

Donnan membrane technique (DMT) for anion measurement.

PubMed

Vega, Flora Alonso; Weng, Liping; Temminghoff, Erwin J M; Van Riemsdijk, Willem H

2010-04-01

Donnan membrane technique (DMT) is developed and tested for determination of free anion concentrations. Time needed to reach the Donnan membrane equilibrium depends on type of ions and the background. The Donnan membrane equilibrium is reached in 1 day for Cl(-), 1-2 days for NO(3)(-), 1-4 days for SO(4)(2-) and SeO(4)(2-), and 1-14 days for H(2)PO(4)(-) in a background of 2-200 mM KCl or K(2)SO(4). The strongest effect of ionic strength on equilibrium time is found for H(2)PO(4)(-), followed by SO(4)(2-) and SeO(4)(2-), and then by Cl(-) and NO(3)(-). The negatively charged organic particles of fulvic and humic acids do not pass the membrane. Two approaches for the measurement of different anion species of the same element, such as SeO(4)(2-) and HSeO(3)(-), using DMT are proposed and tested. These two approaches are based on transport kinetics or response to ionic strength difference. A transport model that was developed previously for cation DMT is applied in this work to analyze the rate-limiting step in the anion DMT. In the absence of mobile/labile complexes, transport tends to be controlled by diffusion in solution at a low ionic strength, whereas at a higher ionic strength, diffusion in the membrane starts to control the transport.

Cation substitution in synthetic meridianiite (MgSO4·11H2O) I: X-ray powder diffraction analysis of quenched polycrystalline aggregates

NASA Astrophysics Data System (ADS)

Fortes, A. Dominic; Browning, Frank; Wood, Ian G.

2012-05-01

Meridianiite, MgSO4·11H2O, is the most highly hydrated phase in the binary MgSO4-H2O system. Lower hydrates in the MgSO4-H2O system have end-member analogues containing alternative divalent metal cations (Ni2+, Zn2+, Mn2+, Cu2+, Fe2+, and Co2+) and exhibit extensive solid solution with MgSO4 and with one another, but no other undecahydrate is known. We have prepared aqueous MgSO4 solutions doped with these other cations in proportions up to and including the pure end-members. These liquids have been solidified into fine-grained polycrystalline blocks of metal sulfate hydrate + ice by rapid quenching in liquid nitrogen. The solid products have been characterised by X-ray powder diffraction, and the onset of partial melting has been quantified using a thermal probe. We have established that of the seven end-member metal sulfates studied, only MgSO4 forms an undecahydrate; ZnSO4 forms an orthorhombic heptahydrate (synthetic goslarite), MnSO4, FeSO4, and CoSO4 form monoclinic heptahydrates (syn. mallardite, melanterite, bieberite, respectively), and CuSO4 crystallises as the well-known triclinic pentahydrate (syn. chalcanthite). NiSO4 forms a new hydrate which has been indexed with a triclinic unit cell of dimensions a = 6.1275(1) Å, b = 6.8628(1) Å, c = 12.6318(2) Å, α = 92.904(2)°, β = 97.678(2)°, and γ = 96.618(2)°. The unit-cell volume of this crystal, V = 521.74(1) Å3, is consistent with it being an octahydrate, NiSO4·8H2O. Further analysis of doped specimens has shown that synthetic meridianiite is able to accommodate significant quantities of foreign cations in its structure; of the order 50 mol. % Co2+ or Mn2+, 20-30 mol. % Ni2+ or Zn2+, but less than 10 mol. % of Cu2+ or Fe2+. In three of the systems we examined, an `intermediate' phase occurred that differed in hydration state both from the Mg-bearing meridianiite end-member and the pure dopant end-member hydrate. In the case of CuSO4, we observed a melanterite-structured heptahydrate at Cu/(Cu + Mg) = 0.5, which we identify as synthetic alpersite [(Mg0.5Cu0.5)SO4·7H2O)]. In the NiSO4- and ZnSO4-doped systems we characterised an entirely new hydrate which could also be identified to a lesser degree in the CuSO4- and the FeSO4-doped systems. The Ni-doped substance has been indexed with a monoclinic unit-cell of dimensions a = 6.7488(2) Å, b = 11.9613(4) Å, c = 14.6321(5) Å, and β = 95.047(3)°, systematic absences being indicative of space-group P21/ c with Z = 4. The unit-cell volume, V = 1,176.59(5) Å3, is consistent with it being an enneahydrate [i.e. (Mg0.5Ni0.5)SO4·9H2O)]. Similarly, the new Zn-bearing enneahydrate has refined unit cell dimensions of a = 6.7555(3) Å, b = 11.9834(5) Å, c = 14.6666(8) Å, β = 95.020(4)°, V = 1,182.77(7) Å3, and the new Fe-bearing enneahydrate has refined unit cell dimensions of a = 6.7726(3) Å, b = 12.0077(3) Å, c = 14.6920(5) Å, β = 95.037(3)°, and V = 1,190.20(6) Å3. The observation that synthetic meridianiite can form in the presence of, and accommodate significant quantities of other ions increases the likelihood that this mineral will occur naturally on Mars—and elsewhere in the outer solar system—in metalliferous brines.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Utell, M.J.; Morrow, P.E.; Hyde, R.W.

Recent epidemiologic studies have emphasized a relationship between alteration in lung function, respiratory symptoms in asthmatics, and elevated levels of sulfate air pollutants. In asthmatics, it has been reported that (1) the more acidic sulfate aerosols, sulfuric acid (H/sub 2/SO/sub 4/) and ammonium bisulfate (NH/sub 4/HSO/sub 4/), provoked the greatest changes in lung function and (2) a definite exposure-response relationship exists for H/sub 2/SO/sub 4/ inhalation. To determine if sulfate aerosol exposure caused increased reactivity to a known bronchoconstrictor, normal and asthmatic subjects inhaled subthreshold doses of carbachol after the following sulfates: H/sub 2/SO/sub 4/, Nh/sub 4/HSO/sub 4/ and sodiummore » bisulfate. A NaCl aerosol served as a control. Exposure times averaged 16 minutes with sulfate concentrations ranging from 100 ..mu..g/m/sup 3/ to 1000 ..mu..g/m/sup 3/. In normal subjects, prior inhalation of either 1000 ..mu../m/sup 3/ H/sub 2/SO/sub 4/ or NH/sub 4/HSO/sub 4/ significantly potentiated the bronchoconstrictor action of carbachol on airway conductance compared to NaCl and carbachol or carbachol alone by t-tests. For the asthmatic group, prior inhalation of either 1000 ..mu..g/m/sup 3/ H/sub 2/SO/sub 4/, or 450 ..mu..g/m/sup 3/ H/sub 2/SO/sub 4/ similarly enhanced the carbachol bronchoconstrictor effect compared to NaCl and carbachol. At the low 100 ..mu..g/m/sup 3/, no sulfates altered the effects of carbachol on pulmonary function. Although mean changes between the sulfate groups did not attain significance by an analysis of variance, it was found that the bronchoconstrictor action of carbachol was potentiated by the sulfate aerosols more or less in relation to their acidity.« less

Four-wavelength near-infrared peripheral oximetry in cardiac surgery patients: a comparison between EQUANOX and O3.

PubMed

Ferraris, Arnaud; Jacquet-Lagrèze, Matthias; Fellahi, Jean-Luc

2018-04-01

Near-infrared spectroscopy (NIRS) is a continuous and noninvasive technology that measures regional tissue oxygen saturation (rSO 2 ). A new 4-wavelength generation of NIRS monitors is now available. We aimed to compare peripheral somatic rSO 2 values given by the 4-wavelength EQUANOX™ 7600 device (Nonin Medical Inc., Plymouth, Mn) and O3™ device (Masimo Corporation, Irvine, CA). Twenty adult patients scheduled for conventional elective cardiac surgery with cardiopulmonary bypass over a 4-month period were included after local Ethics Committee approval. For each patient, 2 NIRS sensors (EQUANOX and O3) were placed over the medial part of the forearm. Thirteen couples of measurements were performed at predefined intraoperative time points. We compared 260 couples of absolute intraoperative rSO 2 values. No significant difference was found between both monitors: EQUANOX median rSO 2 60% (95% CI 57-62) versus O3 median rSO 2 62% (95% CI 61-64), P = 0.103. Bias was 4.0% and limits of agreement were ±26.3%. Significant correlations were evidenced between EQUANOX and O3 rSO 2 absolute values: rho = 0.758 (95% CI 0.701-0.806), P < 0.0001, and rSO 2 percent maximum difference versus baseline: rho = 0.582 (95% CI 0.188-0.815), P = 0.007. While absolute values of rSO 2 given by both devices were equivalent and well correlated, the clinical agreement is probably not acceptable, meaning that EQUANOX and O3 are not interchangeable in routine practice.

C3H7NO2S effect on concrete steel-rebar corrosion in 0.5 M H2SO4 simulating industrial/microbial environment

NASA Astrophysics Data System (ADS)

Okeniyi, Joshua Olusegun; Nwadialo, Christopher Chukwuweike; Olu-Steven, Folusho Emmanuel; Ebinne, Samaru Smart; Coker, Taiwo Ebenezer; Okeniyi, Elizabeth Toyin; Ogbiye, Adebanji Samuel; Durotoye, Taiwo Omowunmi; Badmus, Emmanuel Omotunde Oluwasogo

2017-02-01

This paper investigates C3H7NO2S (Cysteine) effect on the inhibition of reinforcing steel corrosion in concrete immersed in 0.5 M H2SO4, for simulating industrial/microbial environment. Different C3H7NO2S concentrations were admixed, in duplicates, in steel-reinforced concrete samples that were partially immersed in the acidic sulphate environment. Electrochemical monitoring techniques of open circuit potential, as per ASTM C876-91 R99, and corrosion rate, by linear polarization resistance, were then employed for studying anticorrosion effect in steel-reinforced concrete samples by the organic hydrocarbon admixture. Analyses of electrochemical test-data followed ASTM G16-95 R04 prescriptions including probability distribution modeling with significant testing by Kolmogorov-Smirnov and student's t-tests statistics. Results established that all datasets of corrosion potential distributed like the Normal, the Gumbel and the Weibull distributions but that only the Weibull model described all the corrosion rate datasets in the study, as per the Kolmogorov-Smirnov test-statistics. Results of the student's t-test showed that differences of corrosion test-data between duplicated samples with the same C3H7NO2S concentrations were not statistically significant. These results indicated that 0.06878 M C3H7NO2S exhibited optimal inhibition efficiency η = 90.52±1.29% on reinforcing steel corrosion in the concrete samples immersed in 0.5 M H2SO4, simulating industrial/microbial service-environment.

Using dual isotopes to evaluate sources and transformations of nitrate in the West Lake watershed, eastern China.

PubMed

Jin, Zanfang; Qin, Xue; Chen, Lingxiao; Jin, Mantong; Li, Feili

2015-01-01

The West Lake is a World Heritage site in the West Lake watershed in eastern China. In this study, the hydrogeological and dual isotopic approaches were integrated to evaluate the seasonal and spatial variations of nitrate (NO3(-)) in the West Lake watershed, and to characterize NO3(-) sources and transformations. The results revealed that the geochemical facies of the water samples were dominated by Ca(2+)+Na(+)-HCO3(-)+SO4(2)(-) in the surface water and transfer water, Ca(2+)+Na(+)-HCO3(-) and Ca(2+)+Na(+)-SO4(2-) in the groundwater, which most likely reflect natural reactions and anthropogenic inputs. About 13% of the groundwater samples containing NO3(-) exceeded the World Health Organization (WHO) standard of 10 mg N L(-1). NO3(-) was the dominant form of total nitrogen (TN) and was the main surface water contaminant in the West Lake watershed. The δ(15)NNO3 and δ(18)ONO3 values indicated that the dominant NO3(-) sources in surface water were soil nitrogen (soil N) and chemical fertilizers, while the main NO3(-) sources in groundwater were soil N from the forest, chemical fertilizers and manure in the tea garden, domestic sewage from the small, old residential area in the forest as well as urban areas. The distribution of NO3(-) in groundwater was strongly influenced by land use. Results also suggest that there was significant nitrification in surface water and groundwater in the West Lake watershed, and that there were also denitrification processes in groundwater. The annual net fluxes of TN, NO3(-), and NH4(+) into the West Lake were 2.0×10(4), 4.0×10(3), and 1.31×10(4) kg as N, respectively. Copyright © 2015 Elsevier B.V. All rights reserved.

Surface modification with alumina blasting and H2SO4-HCl etching for bonding two resin-composite veneers to titanium.

PubMed

Taira, Yohsuke; Egoshi, Takafumi; Kamada, Kohji; Sawase, Takashi

2014-02-01

The purpose of this study was to investigate the effect of an experimental surface treatment with alumina blasting and acid etching on the bond strengths between each of two resin composites and commercially pure titanium. The titanium surface was blasted with alumina and then etched with 45wt% H2SO4 and 15wt% HCl (H2SO4-HCl). A light- and heat-curing resin composite (Estenia) and a light-curing resin composite (Ceramage) were used with adjunctive metal primers. Veneered specimens were subjected to thermal cycling between 4 and 60°C for 50,000 cycles, and the shear bond strengths were determined. The highest bond strengths were obtained for Blasting/H2SO4-HCl/Estenia (30.2 ± 4.5 MPa) and Blasting/Etching/Ceramage (26.0 ± 4.5 MPa), the values of which were not statistically different, followed by Blasting/No etching/Estenia (20.4 ± 2.4 MPa) and Blasting/No etching/Ceramage (0.8 ± 0.3 MPa). Scanning electron microscopy observations revealed that alumina blasting and H2SO4-HCl etching creates a number of micro- and nanoscale cavities on the titanium surface, which contribute to adhesive bonding. © 2013 Eur J Oral Sci.

Expert opinion survey on the impacts of air pollutants on forests of the USA

Treesearch

J.M. Pye; J.E. de Steiguer; C. Love

1988-01-01

A panel of experts was surveyed to obtain five air pollutants (SO2 NO2, O3, H2SO4, and HNO3) on growth, mortality, and leaf area of forests of the continental U.S. for later input to economic analysis. Results from the first two of three...

Modern marine sediments as a natural analog to the chemically stressed environment of a landfill

USGS Publications Warehouse

Baedecker, M.J.; Back, W.

1979-01-01

Chemical reactions that occur in landfills are analogous to those reactions that occur in marine sediments. Lateral zonation of C, N, S, O, H, Fe and Mn species in landfills is similar to the vertical zonation of these species in marine sediments and results from the following reaction sequence: (1) oxidation of C, N and S species in the presence of dissolved free oxygen to HCO3-, NO3- and SO2-4; (2) after consumption of molecular oxygen, then NO3- is reduced, and Fe and Mn are solubilized; (3) SO2-4 is reduced to sulfide; and (4) organic compounds become the source of oxygen, and CH4 and NH4+ are formed as fermentation products. In a landfill in Delaware the oxidation potential increases downgradient and the redox zones in the reducing plume are characterized by: CH4, NH4+, Fe2+. Mn2+, HCO3- and NO3-. Lack of SO2-4 at that landfill eliminates the sulfide zone. Although it has not been observed at landfills, mineral alteration should result in precipitation of pyrite and/or siderite downgradient. Controls on the pH of leachate are the relative rates of production of HCO3-, NH4+ and CH4. Production of methane by fermentation at landfills results in 13C isotope fractionation and the accumulation of isotopically heavy ??CO2 (+10 to +18??? PDB). Isotope measurements may be useful to determine the extent of CO2 reduction in landfills and extent of dilution downgradient. The boundaries of reaction zones in stressed aquifers are determined by head distribution and flow velocity. Thus, if the groundwater flow is rapid relative to reaction rates, redox zones will develop downgradient. Where groundwater flow velocities are low the zones will overlap to the extent that they may be indeterminate. ?? 1979.

Seasonal variation of fine- and coarse-mode nitrates and related aerosols over East Asia: synergetic observations and chemical transport model analysis

NASA Astrophysics Data System (ADS)

Uno, Itsushi; Osada, Kazuo; Yumimoto, Keiya; Wang, Zhe; Itahashi, Syuichi; Pan, Xiaole; Hara, Yukari; Kanaya, Yugo; Yamamoto, Shigekazu; Fairlie, Thomas Duncan

2017-11-01

We analyzed long-term fine- and coarse-mode synergetic observations of nitrate and related aerosols (SO42-, NO3-, NH4+, Na+, Ca2+) at Fukuoka (33.52° N, 130.47° E) from August 2014 to October 2015. A Goddard Earth Observing System chemical transport model (GEOS-Chem) including dust and sea salt acid uptake processes was used to assess the observed seasonal variation and the impact of long-range transport (LRT) from the Asian continent. For fine aerosols (fSO42-, fNO3-, and fNH4+), numerical results explained the seasonal changes, and a sensitivity analysis excluding Japanese domestic emissions clarified the LRT fraction at Fukuoka (85 % for fSO42-, 47 % for fNO3-, 73 % for fNH4+). Observational data confirmed that coarse NO3- (cNO3-) made up the largest proportion (i.e., 40-55 %) of the total nitrate (defined as the sum of fNO3-, cNO3-, and HNO3) during the winter, while HNO3 gas constituted approximately 40 % of the total nitrate in summer and fNO3- peaked during the winter. Large-scale dust-nitrate (mainly cNO3-) outflow from China to Fukuoka was confirmed during all dust events that occurred between January and June. The modeled cNO3- was in good agreement with observations between July and November (mainly coming from sea salt NO3-). During the winter, however, the model underestimated cNO3- levels compared to the observed levels. The reason for this underestimation was examined statistically using multiple regression analysis (MRA). We used cNa+, nss-cCa2+, and cNH4+ as independent variables to describe the observed cNO3- levels; these variables were considered representative of sea salt cNO3-, dust cNO3-, and cNO3- accompanied by cNH4+), respectively. The MRA results explained the observed seasonal changes in dust cNO3- and indicated that the dust-acid uptake scheme reproduced the observed dust-nitrate levels even in winter. The annual average contributions of each component were 43 % (sea salt cNO3-), 19 % (dust cNO3-), and 38 % (cNH4+ term). The MRA dust-cNO3- component had a high value during the dust season, and the sea salt component made a large contribution throughout the year. During the winter, cNH4+ term made a large contribution. The model did not include aerosol microphysical processes (such as condensation and coagulation between the fine anthropogenic aerosols NO3- and SO42- and coarse particles), and our results suggest that inclusion of aerosol microphysical processes is critical when studying observed cNO3- formation, especially in winter.

Non-sea-salt sulfate and methanesulfonate at American Samoa

NASA Technical Reports Server (NTRS)

Savoie, Dennis L.; Prospero, Joseph M.; Arimoto, Richard; Duce, Robert

1994-01-01

High-volume bulk aerosol samples have been collected at American Samoa (14.25 deg S, 170.58 deg W) on a semicontinuous basis since the system was erected as part of the Sea/Air Exchange Program (SEAREX) in March 1983. In this report we consider those samples collected through May 6, 1992. For most of this period the sample filters were changed once a week. However, during November 1989 and from May 10 to June 10, 1990, in conjunction with the aircraft missions of the NASA Global Backscatter Experiment (GLOBE), the filters were changed daily. All of the samples were analyzed for nonsea-salt (nss) SO4(2-) and NO3(-). Analyses for methanesulfonate (MSA) include all of the 53 daily samples, 22 weekly samples from March 19, 1983, through April 12, 1984, and 96 weekly samples from January 3, 1990, through May 6, 1992. The mean concentrations (in micrograms per cubic meter) were 0.37 for nss SO4(2-), 0.0229 for MSA, 0.114 for NO3(-), and 5.1 for Na(+). Nss SO4(2-) and MSA are strongly linearly correlated in these 171 samples (r(exp 2) = 0.66) and the regression intercept does not differ significantly from zero. The geometric mean (GM) nss SO4(2-)/MSA ratio, 18.1 +/- 0.9 (where +/- indicates the 95% confidence interval of the GM) is about 7% higher than had previously been reported for this station. The ratio exhibits no significant seasonal variation. Although the ratio appeared to be significantly lower in the May - June 1990 daily samples (GM = 15.3 +/- 1.2), a further examination of the results indicated that the variance of the measured ratios from 18.1 (the GM for the whole data set) was attributable almost exclusively to the typical random errors in the analyses as determined from the 1 sigma analytical uncertainties of 5% for MSA and SO4(2-) and 2% for Na(+).

Trinitromethyl Ethers and Other Derivatives as Superior Oxidizers

DTIC Science & Technology

2011-08-26

well as comparable or superior energy content, so that its performance will be at least equivalent to that of AP. Oxygen balance (relative to CO2) for...21]: 6 C(NO2)4 + M+Cl – → ClC(NO2)3 + M+NO2 – ClC(NO2)3 + LiBr → BrC(NO2)3 + ClC(NO2)2Br BrC(NO2)3 + LiCl → ClC(NO2)3 + LiBr ...hindrance parameter α > 8.87 would not be stable; where Ustrain is the strain energy or the potential energy of the molecule in the minimum position

Chemical characteristics of size-resolved atmospheric aerosols in Iasi, north-eastern Romania: nitrogen-containing inorganic compounds control aerosol chemistry in the area

NASA Astrophysics Data System (ADS)

Giorgiana Galon-Negru, Alina; Iulian Olariu, Romeo; Arsene, Cecilia

2018-04-01

This study assesses the effects of particle size and season on the content of the major inorganic and organic aerosol ionic components in the Iasi urban area, north-eastern Romania. Continuous measurements were carried out over 2016 using a cascade Dekati low-pressure impactor (DLPI) performing aerosol size classification in 13 specific fractions over the 0.0276-9.94 µm size range. Fine-particulate Cl-, NO3-, NH4+, and K+ exhibited clear minima during the warm season and clear maxima over the cold season, mainly due to trends in emission sources, changes in the mixing layer depth and specific meteorological conditions. Fine-particulate SO42- did not show much variation with respect to seasons. Particulate NH4+ and NO3- ions were identified as critical parameters controlling aerosol chemistry in the area, and their measured concentrations in fine-mode (PM2.5) aerosols were found to be in reasonable good agreement with modelled values for winter but not for summer. The likely reason is that NH4NO3 aerosols are lost due to volatility over the warm season. We found that NH4+ in PM2.5 is primarily associated with SO42- and NO3- but not with Cl-. Actually, indirect ISORROPIA-II estimations showed that the atmosphere in the Iasi area might be ammonia rich during both the cold and warm seasons, enabling enough NH3 to be present to neutralize H2SO4, HNO3, and HCl acidic components and to generate fine-particulate ammonium salts, in the form of (NH4)2SO4, NH4NO3, and NH4Cl. ISORROPIA-II runs allowed us to estimate that over the warm season ˜ 35 % of the total analysed samples had very strongly acidic pH (0-3), a fraction that rose to ˜ 43 % over the cold season. Moreover, while in the cold season the acidity is mainly accounted for by inorganic acids, in the warm ones there is an important contribution by other compounds, possibly organic. Indeed, changes in aerosol acidity would most likely impact the gas-particle partitioning of semi-volatile organic acids. Overall, we estimate that within the aerosol mass concentration the ionic mass brings a contribution as high as 40.6 %, with the rest still being unaccounted for.

A three-dimensional model of the global ammonia cycle

NASA Astrophysics Data System (ADS)

Dentener, Frank J.; Crutzen, Paul J.

1994-11-01

Using a three-dimensional (3-D) transport model of the troposphere, we calculated the global distributions of ammonia (NH3) and ammonium (NH4(+)), taking into account removal of NH3 on acidic aerosols, in liquid water clouds and by reaction with OH. Our estimated global 10 deg x 10 deg NH3 emission inventory of 45 Tg N-NH3/yr provides a reasonable agreement between calculated wet NH4(+) deposition and measurements and of measured and modeled NH4(+) in aerosols, although in Africa and Asia especially discrepancies exist. NH3 emissions from natural continental ecosystems were calculated applying a canopy compensation point and oceanic NH3 emissions were related to those of DMS (dimethylsulfide). In many regions of the earth, the pH found in rain and cloud water can be attributed to acidity derived from NO, SO2 and DMS emissions and alkalinity from NH3. In the remote lower troposphere, sulfate aerosols are calculated to be almost neutralized to ammonium sulfate (NH4)2SO4, whereas in the middle and upper troposphere, according to our calculations, the aerosol should be more acidic, as a result of the oxidation of DMS and SO2 throughout the troposphere and removal of NH3 on acidic aerosols at lower heights. Although the removal of NH3 by reaction with the OH radical is relatively slow, the intermediate NH2 radical can provide a substantial annual N2O source of 0.9(+0.9/-0.4) Tg, thus contributing by about 5% to estimated global N2O production. The oxidation by OH of NH3 from anthropogenic sources accounts for 10% of the estimated total anthropogenic sources of N2O. This source was not accounted for in previous studies, and is mainly located in the tropics, which have high NH3 and OH concentrations. Biomass burning plumes, containing high NO(x) and NH3 concentrations provide favorable conditions for gas phase N2O production. This source is probably underestimated in this model study, due to the coarse resolution of the 3-D model, and the rather low biomass burning NH3 and NO(x) emissions adopted. The estimate depends heavily on poorly known concentrations of NH3 (and NO(x)) in the tropics, and uncertainties in the rate constants of the reactions NH2 + NO2 yields N2O + H2O (R4), and NH2 + O3 yields NH2O + O2(R7).

Atmospheric deposition and solute export in giant sequoia: mixed conifer watersheds in the Sierra Nevada, California

USGS Publications Warehouse

Stohlgren, Thomas J.; Melack, John M.; Esperanza, Anne M.; Parsons, David J.

1991-01-01

Atmospheric depostion and stream discharge and solutes were measured for three years (September 1984 - August 1987) in two mixed conifer watersheds in Sequoia National Park, in the southern Sierra Nevada of California. The Log Creek watershed (50 ha, 2067-2397 m elev.) is drained by a perennial stream, while Tharp's Creek watershed (13 ha, 2067-2255 m elev.) contains an intermittent stream. Dominant trees in the area include Abies concolor (white fir), Sequoiadendron giganteum (giant sequoia), A. magnifica (red fir), and Pinus lambertiana (sugar pine). Bedrock is predominantly granite and granodiorite, and the soils are mostly Pachic Xerumbrepts. Over the three year period, sulfate (SO42-), nitrate (NO3-), and chloride (Cl-) were the major anions in bulk precipitation with volume-weighted average concentrations of 12.6, 12.3 and 10.0 μeq/1, respectively. Annual inputs of NO3-N, NH4-N and SO4-S from wet deposition were about 60 to 75% of those reported from bulk deposition collectors. Discharge from the two watersheds occurs primarily during spring snowmelt. Solute exports from Log and Tharp's Creeks were dominated by HCO3-, Ca2+ and Na+, while H+, NO3-, NH4+ and PO43- outputs were relatively small. Solute concentrations were weakly correlated with instantaneous stream flow for all solutes (r2 3- (Log Cr. r2=0.72; Tharp's Cr. r2=0.38), Na+ (Log Cr. r2=0.56; Tharp's Cr. r2=0.47), and silicate (Log Cr. r2=0.71; Tharp's Cr. r2=0.49). Mean annual atmospheric contributions of NO3-N (1.6 kg ha-1), NH4-N (1.7 kg ha-1), and SO4-S (1.8 kg ha-1), which are associated with acidic deposition, greatly exceed hydrologic losses. Annual watershed yields (expressed as eq ha-1) of HCO3- exceeded by factors of 2.5 to 37 the annual atmospheric deposition of H+.

Sea salt aerosols as a reactive surface for inorganic and organic acidic gases in the arctic troposphere

NASA Astrophysics Data System (ADS)

Chi, J. W.; Li, W. J.; Zhang, D. Z.; Zhang, J. C.; Lin, Y. T.; Shen, X. J.; Sun, J. Y.; Chen, J. M.; Zhang, X. Y.; Zhang, Y. M.; Wang, W. X.

2015-06-01

Sea salt aerosols (SSA) are dominant particles in the arctic atmosphere and determine the polar radiative balance. SSA react with acidic pollutants that lead to changes of physical and chemical properties of their surface, which in turn alter their hygroscopic and optical properties. Transmission electron microscopy with energy-dispersive X-ray spectrometry was used to analyze morphology, composition, size, and mixing state of individual SSA at Ny-Ålesund, Svalbard in summertime. Individual fresh SSA contained cubic NaCl coated by certain amounts of MgCl2 and CaSO4. Individual partially aged SSA contained irregular NaCl coated by a mixture of NaNO3, Na2SO4, Mg(NO3)2, and MgSO4. The comparison suggests the hydrophilic MgCl2 coating in fresh SSA likely intrigued the heterogeneous reactions at the beginning of SSA and acidic gases. Individual fully aged SSA normally had Na2SO4 cores and an amorphous coating of NaNO3. Elemental mappings of individual SSA particles revealed that as the particles ageing Cl gradually decreased but the C, N, O, and S content increased. 12C14N- mapping from nanoscale secondary ion mass spectrometry indicates that organic matter increased in the aged SSA compared with the fresh SSA. 12C14N- line scans further show that organic matter was mainly concentrated on the aged SSA surface. These new findings indicate that this mixture of organic matter and NaNO3 on particle surfaces determines their hygroscopic and optical properties. These abundant SSA, whose reactive surfaces absorb inorganic and organic acidic gases in the arctic troposphere, need to be incorporated into atmospheric chemical models.

Sea salt aerosols as a reactive surface for inorganic and organic acidic gases in the Arctic troposphere

NASA Astrophysics Data System (ADS)

Chi, J. W.; Li, W. J.; Zhang, D. Z.; Zhang, J. C.; Lin, Y. T.; Shen, X. J.; Sun, J. Y.; Chen, J. M.; Zhang, X. Y.; Zhang, Y. M.; Wang, W. X.

2015-10-01

Sea salt aerosols (SSA) are dominant particles in the Arctic atmosphere and determine the polar radiative balance. SSA react with acidic pollutants that lead to changes in physical and chemical properties of their surface, which in turn alter their hygroscopic and optical properties. Transmission electron microscopy with energy-dispersive X-ray spectrometry was used to analyze morphology, composition, size, and mixing state of individual SSA at Ny-Ålesund, Svalbard, in summertime. Individual fresh SSA contained cubic NaCl coated by certain amounts of MgCl2 and CaSO4. Individual partially aged SSA contained irregular NaCl coated by a mixture of NaNO3, Na2SO4, Mg(NO3)2, and MgSO4. The comparison suggests the hydrophilic MgCl2 coating in fresh SSA likely intrigued the heterogeneous reactions at the beginning of SSA and acidic gases. Individual fully aged SSA normally had Na2SO4 cores and an amorphous coating of NaNO3. Elemental mappings of individual SSA particles revealed that as the particles ageing Cl gradually decreased, the C, N, O, and S content increased. 12C- mapping from nanoscale secondary ion mass spectrometry indicates that organic matter increased in the aged SSA compared with the fresh SSA. 12C- line scan further shows that organic matter was mainly concentrated on the aged SSA surface. These new findings indicate that this mixture of organic matter and NaNO3 on particle surfaces likely determines their hygroscopic and optical properties. These abundant SSA as reactive surfaces adsorbing inorganic and organic acidic gases can shorten acidic gas lifetime and influence the possible gaseous reactions in the Arctic atmosphere, which need to be incorporated into atmospheric chemical models in the Arctic troposphere.

Sea salt aerosols as a reactive surface for inorganic and organic acidic gases in the arctic troposphere

NASA Astrophysics Data System (ADS)

Li, W.

2016-12-01

Sea salt aerosols (SSA) are dominant particles in the arctic atmosphere and determine the polar radiative balance. SSA react with acidic pollutants that lead to changes of physical and chemical properties of their surface, which in turn alter their hygroscopic and optical properties. Transmission electron microscopy with energy-dispersive X-ray spectrometry was used to analyze morphology, composition, size, and mixing state of individual SSA at Ny-Ålesund, Svalbard in summertime. Individual fresh SSA contained cubic NaCl coated by certain amounts of MgCl2 and CaSO4. Individual partially aged SSA contained irregular NaCl coated by a mixture of NaNO3, Na2SO4, Mg(NO3)2, and MgSO4. The comparison suggests the hydrophilic MgCl2 coating in fresh SSA likely intrigued the heterogeneous reactions at the beginning of SSA and acidic gases. Individual fully aged SSA normally had Na2SO4 cores and an amorphous coating of NaNO3. Elemental mappings of individual SSA particles revealed that as the particles ageing Cl gradually decreased but the C, N, O, and S content increased. 12C- mapping from nanoscale secondary ion mass spectrometry indicates that organic matter increased in the aged SSA compared with the fresh SSA. 12C- line scan further shows that organic matter was mainly concentrated on the aged SSA surface. These new findings indicate that this mixture of organic matter and NaNO3 on particle surfaces likely determines their hygroscopic and optical properties. These abundant SSA as reactive surfaces absorbing inorganic and organic acidic gases can shorten acidic gas lifetime and influence the possible gaseous reactions in the arctic atmosphere, which need to be incorporated into atmospheric chemical models in the arctic troposphere.

Effect of phosphate additive on the nitrogen transformation during pig manure composting.

PubMed

Wu, Juan; He, Shengzhou; Liang, Ying; Li, Guoxue; Li, Song; Chen, Shili; Nadeem, Faisal; Hu, Jingwei

2017-07-01

Previous studies revealed that phosphate, as an additive to composting, could significantly reduce NH 3 emission and nitrogen loss through change of pH and nitrogen fixation to form ammonium phosphate. However, few studies have explored the influence of pH change and phosphate additive on NO x - -N, NH 4 + -N, NH 3 , and N 2 O, which are dominate forms of nitrogen in composting. In this study, the equimolar H 3 PO 4 , H 2 SO 4 , and K 2 HPO 4 were added into pig manure composting to evaluate the effect of H + and PO 4 3- on nitrogen transformation. As a result, we reached the conclusion that pH displays significant influence on adsorption from PO 4 3- to NH 4 + . The NH 4 + -N concentration in H 3 PO 4 treatment kept over 3 g kg -1 DM (dry matter) which is obviously higher than that in H 2 SO 4 treatment, and NH 4 + -N concentration in K 2 HPO 4 treatment (pH>8.5) is lower than 0.5 g kg -1 DM because adsorption capacity of PO 4 3- is greatly weakened and NH 4 + -N rapidly transformed to NH 3 -N influenced by high pH value. The N 2 O emission of composting is significantly correlated with incomplete denitrification of NO x - -N, and PO 4 3- addition could raise NO x - -N contents to restrict denitrification and further to promote N 2 O emission. The study reveals the influence mechanism of phosphate additive to nitrogen transformation during composting, presents theoretical basis for additive selection in nitrogen fixation, and lays foundation for study about nitrogen circulation mechanism during composting.

Fractionation of Saprolegnia diclina (Oomycetes) satelite DNAs by AgNO3/Cs2SO4 density gradient centrifugation.

PubMed

Neish, G A; Green, B R

1977-12-14

Saprolegnia diclina DNA has been fractionated using preparative AgNO3/Cs2SO4 and CsCl density gradients. In addition to the previously identified major satellite DNA, there are two minor DNA components banding at 1.682 and 1.701 g - cm(-3) in CsCl. Purified major satellite DNA bands at 1.707 g - cm(-3) giving a base composition of 48% G + C in good agreement with 47% G + C calculated from its Tm value. The nuclear DNA base composition is 58% G + C by both methods. The base composition of the major satellite DNA suggests that it may represent ribosomal DNA cistrons.

Air pollution and emergency department visits for respiratory diseases: A multi-city case crossover study.

PubMed

Szyszkowicz, Mieczysław; Kousha, Termeh; Castner, Jessica; Dales, Robert

2018-05-01

Increasing evidence suggests that ambient air pollution is a major risk factor for both acute and chronic respiratory disease exacerbations and emergencies. The objective of this study was to determine the association between ambient air pollutants and emergency department (ED) visits for respiratory conditions in nine districts across the province of Ontario in Canada. Health, air pollutant (PM 2.5 , NO 2 , O 3 , and SO 2 ), and meteorological data were retrieved from April 2004 to December 2011. Respiratory diseases were categorized as: chronic obstructive pulmonary disease (COPD, including bronchiectasis) and acute upper respiratory diseases. A case-crossover design was used to test the associations between ED visits and ambient air pollutants, stratified by sex and season. For COPD among males, positive results were observed for NO 2 with lags of 3-6 days, for PM 2.5 with lags 1-8, and for SO 2 with lags of 4-8 days. For COPD among females, positive results were observed for O 3 with lags 2-4 days, and for SO 2 among lags of 3-6 days. For upper respiratory disease emergencies among males, positive results were observed for NO 2 (lags 5-8 days), for O 3 , (lags 0-6 days), PM 2.5 (all lags), and SO 2 (lag 8), and among females, positive results were observed for NO 2 for lag 8 days, for O 3 , PM 2.5 among all lags. Our study provides evidence of the associations between short-term exposure to air pollution and increased risk of ED visits for upper and lower respiratory diseases in an environment where air pollutant concentrations are relatively low. Crown Copyright © 2018. Published by Elsevier Inc. All rights reserved.

Microbial reduction of vanadium (V) in groundwater: Interactions with coexisting common electron acceptors and analysis of microbial community.

PubMed

Liu, Hui; Zhang, Baogang; Yuan, Heyang; Cheng, Yutong; Wang, Song; He, Zhen

2017-12-01

Vanadium (V) pollution in groundwater has posed serious risks to the environment and public health. Anaerobic microbial reduction can achieve efficient and cost-effective remediation of V(V) pollution, but its interactions with coexisting common electron acceptors such as NO 3 - , Fe 3+ , SO 4 2- and CO 2 in groundwater remain unknown. In this study, the interactions between V(V) reduction and reduction of common electron acceptors were examined with revealing relevant microbial community and identifying dominant species. The results showed that the presence of NO 3 - slowed down the removal of V(V) in the early stage of the reaction but eventually led to a similar reduction efficiency (90.0% ± 0.4% in 72-h operation) to that in the reactor without NO 3 - . The addition of Fe 3+ , SO 4 2- , or CO 2 decreased the efficiency of V(V) reduction. Furthermore, the microbial reduction of these coexisting electron acceptors was also adversely affected by the presence of V(V). The addition of V(V) as well as the extra dose of Fe 3+ , SO 4 2- and CO 2 decreased microbial diversity and evenness, whereas the reactor supplied with NO 3 - showed the increased diversity. High-throughput 16S rRNA gene pyrosequencing analysis indicated the accumulation of Geobacter, Longilinea, Syntrophobacter, Spirochaeta and Anaerolinea, which might be responsible for the reduction of multiple electron acceptors. The findings of this study have demonstrated the feasibility of anaerobic bioremediation of V(V) and the possible influence of coexisting electron acceptors commonly found in groundwater. Copyright © 2017 Elsevier Ltd. All rights reserved.

Studies on different iron source absorption by in situ ligated intestinal loops of broilers.

PubMed

Jia, Y F; Jiang, M M; Sun, J; Shi, R B; Liu, D S

2015-02-01

The objective of this study was to investigate the iron source absorption in the small intestine of broiler. In situ ligated intestinal loops of 70 birds were poured into one of seven solutions, including inorganic iron (FeSO4, Fe2(SO4)3), organic Fe glycine chelate (Fe-Gly(II), Fe-Gly(III)), the mixtures (FeSO4 with glycine (Fe+Gly(II)), Fe2(SO4)3 with glycine (Fe+Gly(III)), and no Fe source (control). The total volume of 3-mL solution (containing 1 mg of elemental Fe) was injected into intestinal loops, and then 120-min incubation was performed. Compared with inorganic iron groups, in which higher FeSO4 absorption than Fe2(SO4)3 was observed, supplementation with organic Fe glycine chelate significantly increased the Fe concentration in the duodenum and jejunum (P < 0.05), however, decreased DMT1 and DcytB messenger RNA (mRNA) levels (P < 0.05). Organic Fe glycine chelate (Fe-Gly(II), Fe-Gly(III)) increased serum iron concentration (SI), compared with inorganic 3 valence iron groups (Fe2(SO4)3 and Fe+Gly(III)) (P < 0.05); moreover, lower TIBC value was observed for the chelate (P < 0.05); however, mixture of inorganic iron and glycine did not have a positive role at DMT1 and DcytB mRNA levels, SI and Fe concentrations in the small intestine. Those results indicated that the absorption of organic Fe glycine chelate was more effective than that of inorganic Fe, and the orders of iron absorption in the small intestine were: Fe-Gly(II), Fe-Gly(III) > FeSO4, Fe+Gly(II) > Fe2(SO4)3, Fe+Gly(III). Additionally, the simple mixture of inorganic iron and glycine could not increase Fe absorption, and the duodenum was the main site of Fe absorption in the intestines of broilers and the ileum absorbed iron rarely.

Influence of Water on the H2SO4 Yield from the Ozonolysis of 2,3-dimethyl-butene (TME) in Presence of SO2

NASA Astrophysics Data System (ADS)

Véronique, D.; Kukui, A.; Chen, H.; Mellouki, A.

2016-12-01

The influence of the water vapor content on the yield of H2SO4 from the ozonolysis of 2,3-dimethyl-butene (TME) in presence of SO2 was studied using laminar flow reactor coupled with Chemical Ionisation Mass Spectrometer (CIMS) for the H2SO4 monitoring within the range of H2O from 10 ppmv to 3×104 ppmv at different concentrations of TME, O3, SO2. The observed dependences of the H2SO4 yield on H2O concentration can be interpreted by assuming two different paths of the H2SO4 formation: 1) via the formation of SO3 in the reaction of Stabilized Criegee Intermediate (SCI) with SO2 (2a) followed by the reaction of SO3 with H2O (3) and 2) via the formation of stabilized secondary ozonide (SOZ) (2b) producing H2SO4 in the reaction with H2O (4a) in competition with the SOZ decomposition to other products (5): O3+TME => (CH3)2COO (1) (CH3)2COO + SO2 => SO3 (2a) => SOZ (2b) SO3 + H2O => H2SO4 (3) SOZ + H2O => H2SO4 (or SO3) (4a) SOZ + M => products (5) The yield of the SCI, SOZ and the rates of the SCI and SOZ decomposition relative to their reactions with SO2 and H2O, respectively, were estimated from the dependencies of the H2SO4 yield on the concentrations of the reactants.

Precipitation composition and wet deposition temporal pattern in Central Serbia for the period from 1998 to 2004.

PubMed

Golobocanin, D; Zujić, A; Milenković, A; Miljević, N

2008-07-01

Bulk samples collected on a daily basis at three principal meteorological stations in central Serbia were analyzed on chloride (Cl(-)), nitrate (NO(3)(-)), sulfate (SO(4)(2-)), sodium (Na(+)), ammonium (NH(4)(+)), potassium (K(+)), calcium (Ca(2+)), and magnesium (Mg(2+)) in addition to precipitation amount, pH and conductivity measurements over the period 1998-2004. The data were subjected to variety of analyses (linear regression, principal component analysis, time series analysis) to characterize precipitation chemistry in the study area. The most abundant ion was SO(2-)(4) with annual volume weighted mean concentration of 242 microeq L(-1). Neutralization of precipitation acidity occurs both as a result of the dissolution of alkaline compounds containing Ca(2+), Mg(2+), and K(+) as well as the absorption of ammonia. The ratio of SO(4)(2-)/NO(3)(-) was above 5, which indicated that the combustion process of low-grade domestic lignite for electricity generation from coal-fired thermal power plants was the main source of pollution in the investigated area. A considerable mean annual bulk wet deposition of SO(4)-S determined by precipitation amount and concentrations of sulfate in the precipitation was calculated to be 12-35 kg ha(-1).

Development of a new corona discharge based ion source for high resolution time-of-flight chemical ionization mass spectrometer to measure gaseous H2SO4 and aerosol sulfate

NASA Astrophysics Data System (ADS)

Zheng, Jun; Yang, Dongsen; Ma, Yan; Chen, Mindong; Cheng, Jin; Li, Shizheng; Wang, Ming

2015-10-01

A new corona discharge (CD) based ion source was developed for a commercial high-resolution time-of-flight chemical ionization mass spectrometer (HRToF-CIMS) (Aerodyne Research Inc.) to measure both gaseous sulfuric acid (H2SO4) and aerosol sulfate after thermal desorption. Nitrate core ions (NO3-) were used as reagent ions and were generated by a negative discharge in zero air followed by addition of excess nitrogen dioxide (NO2) to convert primary ions and hydroxyl radicals (OH) into NO3- ions and nitric acid (HNO3). The CD-HRToF-CIMS showed no detectable interference from hundreds parts per billion by volume (ppbv) of sulfur dioxide (SO2). Unlike the atmospheric pressure ionization (API) ToF-CIMS, the CD ion source was integrated onto the ion-molecule reaction (IMR) chamber and which made it possible to measure aerosol sulfate by coupling to a filter inlet for gases and aerosols (FIGAERO). Moreover, compared with a quadrupole-based mass spectrometer, the desired HSO4- signal was detected by its exact mass of m/z 96.960, which was well resolved from the potential interferences of HCO3-ṡ(H2O)2 (m/z 97.014) and O-ṡH2OṡHNO3 (m/z 97.002). In this work, using laboratory-generated standards the CD-HRToF-CIMS was demonstrated to be able to detect as low as 3.1 × 105 molecules cm-3 gaseous H2SO4 and 0.5 μg m-3 ammonium sulfate based on 10-s integration time and two times of the baseline noise. The CD ion source had the advantages of low cost and a simple but robust structure. Since the system was non-radioactive and did not require corrosive HNO3 gas, it can be readily field deployed. The CD-HRToF-CIMS can be a powerful tool for both field and laboratory studies of aerosol formation mechanism and the chemical processes that were critical to understand the evolution of aerosols in the atmosphere.

Chemical composition of precipitation in a Mexican Maya region

NASA Astrophysics Data System (ADS)

Bravo, H. A.; Saavedra, M. I. R.; Sánchez, P. A.; Torres, R. J.; Granada, L. M. M.

The chemical characteristics of wet precipitation in Puerto Morelos, Quintana Roo State, Mexico, were measured from April 1994 to December 1995. Puerto Morelos is located in the Caribbean Mayan coastal region of the Peninsula of Yucatan, and is normally exposed to winds from the Caribbean region. Wetfall was analyzed for pH, conductivity and Cl -, NO 3-, SO 42-, Na +, NH 4+, K +, Mg 2+ and Ca 2+ ion concentrations. Volume-weighted mean pH for the whole sampling period was 5.35, although values as low as 4.6 were measured in several rain samples. Concentrations of all species correlated negatively with rain volume. Sea-salt aerosols contributed with most of the Na +, Cl -, Mg 2+, K + and SO 42- found in wet precipitation. The mean [SO 42-excess] was 9.7 μEq l -1, which agrees with the background hemispheric values of ≈10 μEq l -1 reported elsewhere. The mean [NO 3-] was 11.4 μEq l -1, almost four times higher than the background hemispheric value of ≈2.5 μEq l -1 reported elsewhere. However, a major component causing the slight acidity character of rain in Puerto Morelos seems to be H 2SO 4.

Characterization of trace gases measured over Alberta oil sands mining operations: 76 speciated C2-C10 volatile organic compounds (VOCs), CO2, CH4, CO, NO, NO2, NOy, O3 and SO2

NASA Astrophysics Data System (ADS)

Simpson, I. J.; Blake, N. J.; Barletta, B.; Diskin, G. S.; Fuelberg, H. E.; Gorham, K.; Huey, L. G.; Meinardi, S.; Rowland, F. S.; Vay, S. A.; Weinheimer, A. J.; Yang, M.; Blake, D. R.

2010-08-01

Oil sands comprise 30% of the world's oil reserves and the crude oil reserves in Canada's oil sands deposits are second only to Saudi Arabia. The extraction and processing of oil sands is much more challenging than for light sweet crude oils because of the high viscosity of the bitumen contained within the oil sands and because the bitumen is mixed with sand and contains chemical impurities such as sulphur. Despite these challenges, the importance of oil sands is increasing in the energy market. To our best knowledge this is the first peer-reviewed study to characterize volatile organic compounds (VOCs) emitted from Alberta's oil sands mining sites. We present high-precision gas chromatography measurements of 76 speciated C2-C10 VOCs (alkanes, alkenes, alkynes, cycloalkanes, aromatics, monoterpenes, oxygenates, halocarbons, and sulphur compounds) in 17 boundary layer air samples collected over surface mining operations in northeast Alberta on 10 July 2008, using the NASA DC-8 airborne laboratory as a research platform. In addition to the VOCs, we present simultaneous measurements of CO2, CH4, CO, NO, NO2, NOy, O3 and SO2, which were measured in situ aboard the DC-8. Methane, CO, CO2, NO, NO2, NOy, SO2 and 53 VOCs (e.g., halocarbons, sulphur species, NMHCs) showed clear statistical enhancements (up to 1.1-397×) over the oil sands compared to local background values and, with the exception of CO, were higher over the oil sands than at any other time during the flight. Twenty halocarbons (e.g., CFCs, HFCs, halons, brominated species) either were not enhanced or were minimally enhanced (< 10%) over the oil sands. Ozone levels remained low because of titration by NO, and three VOCs (propyne, furan, MTBE) remained below their 3 pptv detection limit throughout the flight. Based on their mutual correlations, the compounds emitted by the oil sands industry fell into two groups: (1) evaporative emissions from the oil sands and its products and/or from the diluent used to lower the viscosity of the extracted bitumen (i.e., C4-C9 alkanes, C5-C6 cycloalkanes, C6-C8 aromatics), together with CO; and (2) emissions associated with the mining effort (i.e., CO2, CO, CH4, NO, NO2, NOy, SO2, C2-C4 alkanes, C2-C4 alkenes, C9 aromatics, short-lived solvents such as C2Cl4 and C2HCl3, and longer-lived species such as HCFC-22 and HCFC-142b). Prominent in the second group, SO2 and NO were remarkably enhanced over the oil sands, with maximum enhancements of 38.7 and 5.0 ppbv, or 383 and 319× the local background, respectively. The SO2 enhancements are comparable to maximum values measured in heavily polluted megacities such as Mexico City and are attributed to coke combustion. By contrast, relatively poor correlations between CH4 ethane and propane suggest low natural gas leakage despite its heavy use at the surface mining sites. In addition to the emission of many trace gases, the natural drawdown of OCS by vegetation was absent above the surface mining operations, presumably because of the widespread land disturbance. Unexpectedly, the mixing ratios of α- and β-pinene were much higher over the oil sands (up to 217 and 610 pptv, respectively) than over vegetation in the background boundary layer (20±7 and 84±24 pptv, respectively), and the pinenes correlated well with several industrial tracers that were elevated in the oil sands plumes. Because so few independent measurements from the oil sands mining industry exist, this study provides an important initial characterization of trace gas emissions from oil sands surface mining operations.

Fetal Hypothalamus-Pituitary-Adrenal Responses to Estradiol Sulfate

PubMed Central

2011-01-01

Estradiol (E2) is an important modifier of the activity of the fetal hypothalamus-pituitary-adrenal axis. We have reported that estradiol-3-sulfate (E2SO4) circulates in fetal blood in far higher concentrations than E2 and that the fetal brain expresses steroid sulfatase, required for local deconjugation of E2SO4. We performed the present study to test the hypothesis that chronic infusion of E2SO4 chronically increases ACTH and cortisol secretion and that it shortens gestation. Chronically catheterized fetal sheep were treated with E2SO4 intracerebroventricular (n = 5), E2SO4 iv (n = 4), or no steroid infusion (control group, n = 5). Fetuses were subjected to arterial blood sampling every other day until spontaneous birth for plasma hormone analysis. Treatment with E2SO4 attenuated preparturient increases in ACTH secretion near term without affecting the ontogenetic rise in plasma cortisol. Infusion of E2SO4 intracerebroventricularly significantly increased plasma E2, plasma E2SO4, and plasma progesterone and shortened gestation compared with all other groups. These results are consistent with the conclusion that E2SO4: 1) interacts with the hypothalamus-pituitary-adrenal axis primarily by stimulating cortisol secretion and inhibiting ACTH and pro-ACTH secretion by negative feedback; and 2) stimulates the secretion of E2 and E2SO4. We conclude that the endocrine response to E2SO4 in the fetus is not identical with the response to E2. PMID:21952234

Electron-induced chemistry in microhydrated sulfuric acid clusters

NASA Astrophysics Data System (ADS)

Lengyel, Jozef; Pysanenko, Andriy; Fárník, Michal

2017-11-01

We investigate the mixed sulfuric acid-water clusters in a molecular beam experiment with electron attachment and negative ion mass spectrometry and complement the experiment by density functional theory (DFT) calculations. The microhydration of (H2SO4)m(H2O)n clusters is controlled by the expansion conditions, and the electron attachment yields the main cluster ion series (H2SO4)m(H2O)nHSO4- and (H2O)nH2SO4-. The mass spectra provide an experimental evidence for the onset of the ionic dissociation of sulfuric acid and ion-pair (HSO4- ṡ ṡ ṡ H3O+) formation in the neutral H2SO4(H2O)n clusters with n ≥ 5 water molecules, in excellent agreement with the theoretical predictions. In the clusters with two sulfuric acid molecules (H2SO4)2(H2O)n this process starts as early as n ≥ 2 water molecules. The (H2SO4)m(H2O)nHSO4- clusters are formed after the dissociative electron attachment to the clusters containing the (HSO4- ṡ ṡ ṡ H3O+) ion-pair structure, which leads to the electron recombination with the H3O+ moiety generating H2O molecule and the H-atom dissociation from the cluster. The (H2O)nH2SO4- cluster ions point to an efficient caging of the H atom by the surrounding water molecules. The electron-energy dependencies exhibit an efficient electron attachment at low electron energies below 3 eV, and no resonances above this energy, for all the measured mass peaks. This shows that in the atmospheric chemistry only the low-energy electrons can be efficiently captured by the sulfuric acid-water clusters and converted into the negative ions. Possible atmospheric consequences of the acidic dissociation in the clusters and the electron attachment to the sulfuric acid-water aerosols are discussed.

The State of Ambient Air Quality in Two Ugandan Cities: A Pilot Cross-Sectional Spatial Assessment.

PubMed

Kirenga, Bruce J; Meng, Qingyu; van Gemert, Frederik; Aanyu-Tukamuhebwa, Hellen; Chavannes, Niels; Katamba, Achilles; Obai, Gerald; van der Molen, Thys; Schwander, Stephan; Mohsenin, Vahid

2015-07-15

Air pollution is one of the leading global public health risks but its magnitude in many developing countries' cities is not known. We aimed to measure the concentration of particulate matter with aerodynamic diameter <2.5 µm (PM2.5), nitrogen dioxide (NO2), sulfur dioxide (SO2), and ozone (O3) pollutants in two Ugandan cities (Kampala and Jinja). PM2.5, O3, temperature and humidity were measured with real-time monitors, while NO2 and SO2 were measured with diffusion tubes. We found that the mean concentrations of the air pollutants PM2.5, NO2, SO2 and O3 were 132.1 μg/m3, 24.9 µg/m3, 3.7 µg/m3 and 11.4 μg/m3, respectively. The mean PM2.5 concentration is 5.3 times the World Health Organization (WHO) cut-off limits while the NO2, SO2 and O3 concentrations are below WHO cut-off limits. PM2.5 levels were higher in Kampala than in Jinja (138.6 μg/m3 vs. 99.3 μg/m3) and at industrial than residential sites (152.6 μg/m3 vs. 120.5 μg/m3) but residential sites with unpaved roads also had high PM2.5 concentrations (152.6 μg/m3). In conclusion, air pollutant concentrations in Kampala and Jinja in Uganda are dangerously high. Long-term studies are needed to characterize air pollution levels during all seasons, to assess related public health impacts, and explore mitigation approaches.

Effect of ammonium sulfate, ammonium chloride and root-zone acidity on inorganic ion content of tobacco

NASA Technical Reports Server (NTRS)

Vessey, J. K.; Raper, C. D. Jr; Henry, L. T.; Raper CD, J. r. (Principal Investigator)

1990-01-01

Tobacco plants (Nicotiana tabacum L. cv NC82) were supplied with (NH4)2SO4 or NH4Cl at root-zone pH of 6.0 and 4.5 in hydroponic culture for 28 days. Dry matter accumulation, total N and C content, and leaf area and number were not affected by the NH4+ source or root-zone pH. Plants supplied with NH4Cl accumulated up to 1.2 mM Cl g DW-1, but accumulated 37% less inorganic H2PO4- and 47% less SO4(2-) than plants supplied with (NH4)2SO4. The large Cl- accumulation resulted in NH4Cl- supplied plants having a 31% higher inorganic anion (NO3-, H2, PO4-, SO4(2-), and Cl-) charge. This higher inorganic anion charge in the NH4Cl-supplied plants was balanced by a similar increase in K+ charge. Plants supplied with NH4Cl accumulated greater concentrations of Cl- in leaves (up to 5.1% of DW) than plants supplied with (NH4)2SO4 (less than -% DW). Despite the high Cl- concentration of leaves in NH4Cl supplied plants, these plants showed no symptoms of Cl- toxicity. This demonstrates that toxicity symptoms are not due solely to an interaction between high Cl- concentration in tissue and NH4+ nutrition. The increase in root-zone acidity to pH 4.5 from 6.0 did not induce toxicity symptoms.

Wet chemical passivation of YBa2Cu3O(7-x)

NASA Technical Reports Server (NTRS)

Vasquez, R. P.; Hunt, B. D.; Foote, M. C.

1990-01-01

Wet chemical techniques are described for treatment of YBa2Cu3O(7-x) surfaces, which result in the formation of native compounds known to have little or no reactivity to water. Suitable native compounds include CuI, BaSO4, CuS, Cu2S, YF3, and the oxalates. Formation of surface layers in which these nonreactive native compounds are major constituents is verified with X-ray photoelectron spectroscopy (XPS) measurements on YBa2Cu3O(7-x) films treated with dilute solutions of HI, H2SO4, Na2S, HF, or H2C2O4. No significant changes are observed in the XPS spectra when the sulfide, sulfate, or oxalate films are dipped in water, while the iodide and fluoride films show evidence of reaction with water. X-ray diffraction measurements show that the superconducting phase is absent in the sulfide film, but is unaffected by the oxalate and sulfate treatments.

Spatiotemporal evaluation of the groundwater quality in Gharbiya Governorate, Egypt.

PubMed

Masoud, Alaa A; El Bouraie, Mohamed M; El-Nashar, Wafaa; Mashaly, Hamdy

2017-03-01

Groundwater quality indicators were monitored over 6 years (2007-2012) from 55 drinking water supply wells in Gharbiya Governorate (Egypt). The prime objective was to characterize, for the first time, the governorate-wide significant and sustained trends in the concentrations of the groundwater pollutants. Quality indicators included turbidity, pH, total dissolved solid (TDS), electric conductivity (EC), Cl - , SO 4 2- , Na + , total alkalinity, hardness (total, Mg, and Ca), Fe 2+ , Mn 2+ , Cu 2+ , Zn 2+ , F - , NH 4 + , NO 2 - , NO 3 - , PO 4 3- , dissolved oxygen (DO), and SiO 2 contents. Detection and estimation of trends and magnitude were carried out applying the non-parametric Mann-Kendall and Thiel-Sen trend statistical tests, respectively. Factor analysis was applied to identify significant sources of quality variation and their loads. Violation of groundwater quality standards clarified emergence of Mn 2+ (46%), Fe 2+ (35%), and NH 4 + (33%). Out of the 55 wells, notable upward trends (deterioration) were significant (>95% level) for TDS (89%), NO 3 - (85), PO 4 3- (75%), NH 4 + (65%), total alkalinity (62%), Fe 2+ (58%), NO 2 - (47%), Mg hardness (36%), turbidity (25%), and Mn 2+ (24%). Ranges of attenuation rates (mg/l/year) varied for TDS (24.3, -0.7), Mg hardness (3.8, -0.85), total alkalinity (1.4, -1.2), NO 3 - (0.52, -0.066), PO 4 3- (0.069, -0.064), NH 4 + (0.038, -0.019), Mn 2+ (0.015, -0.044), Fe 2+ (0.006, -0.014), and NO 2 - (0.006, -0.00003). Highest rates marked Tanta (total alkalinity and Fe 2+ ), Al-Mehala Al-Kubra (TDS, Mg hardness, and NO 3 - ), Kafr Al-Zayat (NH 4 + ), Zifta (Mn 2+ ), Bassyun (NO 2 - ), and Qutur (PO 4 3- ). Precision of the trend estimate varied in goodness of fit, for TDS (86%), Mg hardness (76%), total alkalinity (73%), PO 4 3- (67.4%), NH 4 + (66.8%), Mn 2+ (55%), and Fe 2+ (49.6%), arranged in decreasing order. Two main varimax-rotated factors counted for more than 55% of the quality variance and, in particular, significant loads of salinity (TDS, EC, Cl - , Na + , and SO 4 2- ), followed by the alkalinity, hardness, redox potentials (Mn 2+ and Fe 2+ ), and NH 4 + , in decreasing order were identified. The spatial-temporal variation in pollutants originated from organic matter degradation, either naturally from the aquifer peaty sediments or anthropogenic due to improper well head protection in the urban centers or from the agricultural drains in low relief areas. Considering the latest contents of indicators and their rate of increase, the time that the permissible limits would be reached can be accurately estimated and alleviative actions could be effectively set.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Levendis, Y.A.

A study was conducted to determine the efficacy of carboxylic calcium and magnesium salts (e.g., calcium magnesium acetate or CMA, CaMg{sub 2}(CH{sub 2}COOH){sub 6}) for the simultaneous removal of SO{sub 2} and NO{sub x} in oxygen-lean atmospheres. Experiments were performed in a high-temperature furnace that simulated the post-flame environment of a coal-fired boiler by providing similar temperatures and partial pressures of SO{sub 2}, NO{sub x} CO{sub 2} and O{sub 2}. When injected into a hot environment, the salts calcined and formed highly porous {open_quotes}popcorn{close_quotes}-like cenospheres. Residual MgO and/or CaCO{sub 3} and CaO reacted heterogeneously with SO{sub 2} to form MgSO{submore » 4} and/or CaCO{sub 4}. The organic components - which can be manufactured from wastes such as sewage sludge - gasified and reduced NO{sub x }to N{sub 2} efficiently if the atmosphere was moderately fuel-rich. Dry-injected CMA particles at a Ca/S ratio of 2, residence time of 1 second and bulk equivalence ratio of 1.3 removed over 90% of SO{sub 2} and NO{sub x} at gas temperatures {>=} 950{degrees}C. When the furnace isothermal zone was {<=} 950{degrees}C, Ca was essentially inert in the furnace quenching zone, while Mg continued to sorb SO{sub 2} as the gas temperature cooled at a rate of -130{degrees}C/sec. Hence, the removal of SO{sub 2} by CMA could continue for nearly the entire residence time of emissions in the exhaust stream of a power plant. Additional research is needed to improve the efficiency and reduce the cost of the relatively expensive carboxylic acid salts as dual SO{sub 2}-NO{sub x} reduction agents. For example, wet injection of the salts could be combined with less expensive hydrocarbons such as lignite or even polymers such as poly(ethylene) that could be extracted from the municipal waste stream.« less

Atmospheric wet deposition of sulfur and nitrogen in Jiuzhaigou National Nature Reserve, Sichuan Province, China.

PubMed

Qiao, Xue; Xiao, Weiyang; Jaffe, Daniel; Kota, Sri Harsha; Ying, Qi; Tang, Ya

2015-04-01

In the last two decades, remarkable ecological changes have been observed in Jiuzhaigou National Nature Reserve (JNNR). Some of these changes might be related to excessive deposition of sulfur (S) and nitrogen (N), but the relationship has not been quantified due to lack of monitoring data, particularly S and N deposition data. In this study, we investigated the concentrations, fluxes, and sources of S and N wet deposition in JNNR from April 2010 to May 2011. The results show that SO4(2-), NO3-, and NH4+ concentrations in the wet deposition were 39.4-170.5, 6.2-34.8, and 0.2-61.2 μeq L(-1), with annual Volume-Weighted Mean (VWM) concentrations of 70.5, 12.7, and 13.4 μeq L(-1), respectively. Annual wet deposition fluxes of SO4(2-), NO3-, and NH4+ were 8.06, 1.29, and 1.39 kg S(N)ha(-1), respectively, accounting for about 90% of annual atmospheric inputs of these species at the monitoring site. The results of Positive Matrix Factorization (PMF) analysis show that fossil fuel combustion, agriculture, and aged sea salt contributed to 99% and 83% of annual wet deposition fluxes of SO4(2-) and NO3-, respectively. Agriculture alone contributed to 89% of annual wet deposition flux of NH4+. Although wet deposition in JNNR was polluted by anthropogenic acids, the acidity was largely neutralized by the Ca2+ from crust and 81% of wet deposition samples had a pH higher than 6.00. However, acid rain mainly caused by SO4(2-) continued to occur in the wet season, when ambient alkaline dust concentration was lower. Since anthropogenic emissions have elevated S and N deposition and caused acid rain in JNNR, further studies are needed to better quantify the regional sources and ecological effects of S and N deposition for JNNR. Copyright © 2014 Elsevier B.V. All rights reserved.

Chemical characteristics of PM2.5 aerosol in Incheon, Korea

NASA Astrophysics Data System (ADS)

Choi, Jong-Kyu; Heo, Jong-Bae; Ban, Soo-Jin; Yi, Seung-Muk; Zoh, Kyung-Duk

2012-12-01

We examined the characteristics, sources, and distribution of PM2.5 and carbonaceous species in particulate samples collected from June 2009 to May 2010 in Incheon, Korea. The average PM2.5 concentration (41.9 ± 9.0 μg m-3) exceeded the annual level set by the United States' National Ambient Air Quality Standards (15 μg m-3). The major fraction of PM2.5 consisted of ionic species (accounting for 38.9 ± 8.8%), such as NO3-, SO42-, and NH4+, as well as organic carbon (OC) (accounting for 18.9 ± 5.1%). We also analyzed the seasonal variation in PM2.5 and secondary aerosols such as NO3- and SO42- in PM2.5. While SO42- concentrations were higher in spring and summer, the concentration of PM2.5 and NO3- were the highest in winter. SO42- concentrations were higher during the spring and summer, but PM2.5 and NO3- were highest during the winter. As an important aerosol indicator, water-soluble organic carbon (WSOC) (mean 4.7 ± 0.8 μg m-3, 58.9 ± 10.7% of total OC) showed a strong relationship with NO3-, SO42-, and SOC (R2 = 0.56, 0.67, and 0.65, respectively), which was indicative of favorable conditions for SOC formation during the sampling period. Among the individual organic aerosols measured, n-alkanes, n-alkanoic acids, levoglucosan, and phthalates were major components, whereas PAHs (polycyclic aromatic hydrocarbons), oxy-PAHs, hopanes, and cholestanes were minor components. The concentration of organic compounds during smoggy periods was higher than during non-event periods. The n-alkane and n-alkanoic acid species during the smoggy periods were 10-14 times higher than during the normal period. Using principal component analysis coupled with multiple linear regression analysis, we identified the primary sources of PM2.5 to be motor vehicle/sea salt, secondary organic aerosols, combustion, biogenic/meat cooking, and soil sources.

Modeling dry and wet deposition of sulfate, nitrate, and ammonium ions in Jiuzhaigou National Nature Reserve, China using a source-oriented CMAQ model: Part II. Emission sector and source region contributions.

PubMed

Qiao, Xue; Tang, Ya; Kota, Sri Harsha; Li, Jingyi; Wu, Li; Hu, Jianlin; Zhang, Hongliang; Ying, Qi

2015-11-01

A source-oriented Community Multiscale Air Quality (CMAQ) model driven by the meteorological fields generated by the Weather Research and Forecasting (WRF) model was used to study the dry and wet deposition of nitrate (NO3(-)), sulfate (SO4(2-)), and ammonium (NH4(+)) ions in the Jiuzhaigou National Nature Reserve (JNNR), China from June to August 2010 and to identify the contributions of different emission sectors and source regions that were responsible for the deposition fluxes. Contributions from power plants, industry, transportation, domestic, biogenic, windblown dust, open burning, fertilizer, and manure management sources to deposition fluxes in JNNR watershed and four EANET sites are determined. In JNNR, 96%, 82%, and 87% of the SO4(2-), NO3(-) and NH4(+) deposition fluxes are in the form of wet deposition of the corresponding aerosol species. Industry and power plants are the two major sources of SO4(2-) deposition flux, accounting for 86% of the total wet deposition of SO4(2-), and industry has a higher contribution (56%) than that of power plants (30%). Power plants and industry are also the top sources that are responsible for NO3(-) wet deposition, and contributions from power plants (30%) are generally higher than those from industries (21%). The major sources of NH4(+) wet deposition flux in JNNR are fertilizer (48%) and manure management (39%). Source-region apportionment confirms that SO2 and NOx emissions from local and two nearest counties do not have a significant impact on predicted wet deposition fluxes in JNNR, with contributions less than 10%. While local NH3 emissions account for a higher fraction of the NH4(+) deposition, approximately 70% of NH4(+) wet deposition in JNNR originated from other source regions. This study demonstrates that S and N deposition in JNNR is mostly from long-range transport rather than from local emissions, and to protect JNNR, regional emission reduction controls are needed. Copyright © 2015 Elsevier B.V. All rights reserved.

21 CFR 184.1230 - Calcium sulfate.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Calcium sulfate. 184.1230 Section 184.1230 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DIRECT... GRAS § 184.1230 Calcium sulfate. (a) Calcium sulfate (CaSO4, CAS Reg. No. 7778-18-9 or CaSO4·2H2O, CAS...

Twenty-year inter-annual trends and seasonal variations in precipitation and stream water chemistry at the Bear Brook Watershed in Maine, USA.

PubMed

Navrátil, Tomas; Norton, Stephen A; Fernandez, Ivan J; Nelson, Sarah J

2010-12-01

Mean annual concentration of SO4(-2) in wet-only deposition has decreased between 1988 and 2006 at the paired watershed study at Bear Brook Watershed in Maine, USA (BBWM) due to substantially decreased emissions of SO(2). Emissions of NO(x) have not changed substantially, but deposition has declined slightly at BBWM. Base cations, NH4+, and Cl(-) concentrations were largely unchanged, with small irregular changes of <1 μeq L(-1) per year from 1988 to 2006. Precipitation chemistry, hydrology, vegetation, and temperature drive seasonal stream chemistry. Low flow periods were typical in June-October, with relatively greater contributions of deeper flow solutions with higher pH; higher concentrations of acid-neutralizing capacity, Si, and non-marine Na; and low concentrations of inorganic Al. High flow periods during November-May were typically dominated by solutions following shallow flow paths, which were characterized by lower pH and higher Al and DOC concentrations. Biological activity strongly controlled NO3- and K(+). They were depressed during the growing season and elevated in the fall. Since 1987, East Bear Brook (EB), the reference stream, has been slowly responding to reduced but still elevated acid deposition. Calcium and Mg have declined fairly steadily and faster than SO4(-2), with consequent acidification (lower pH and higher inorganic Al). Eighteen years of experimental treatment with (NH(4))(2)SO(4) enhanced acidification of West Bear Brook's (WB) watershed. Despite the manipulation, NH4+ concentration remained below detection limits at WB, while leaching of NO3- increased. The seasonal pattern for NO3- concentrations in WB, however, remained similar to EB. Mean monthly concentrations of SO4(-2) have increased in WB since 1989, initially only during periods of high flow, but gradually also during base flow. Increases in mean monthly concentrations of Ca(2+), Mg(2+), and K(+) due to the manipulation occurred from 1989 until about 1995, during the depletion of base cations in shallow flow paths in WB. Progressive depletion of Ca and Mg at greater soil depth occurred, causing stream concentrations to decline to pre-manipulation values. Mean monthly Si concentrations did not change in EB or WB, suggesting that the manipulation had no effect on mineral weathering rates. DOC concentrations in both streams did not exhibit inter- or intra-annual trends.

Characterization of major pollution events (dust, haze, and two festival events) at Agra, India.

PubMed

Pachauri, Tripti; Singla, Vyoma; Satsangi, Aparna; Lakhani, Anita; Kumari, K Maharaj

2013-08-01

Total suspended particulate (TSP) samples were collected during dust, haze, and two festival events (Holi and Diwali) from February 2009 to June 2010. Pollutant gases (NO2, SO2, and O3) along with the meteorological parameters were also measured during the four pollution events at Agra. The concentration of pollutant gases decreases during dust events (DEs), but the levels of the gases increase during other pollution events indicating the impact of anthropogenic emissions. The mass concentrations were about two times higher during pollution events than normal days (NDs). High TSP concentrations during Holi and Diwali events may be attributed to anthropogenic activities while increased combustion sources in addition to stagnant meteorological conditions contributed to high TSP mass during haze events. On the other hand, long-range transport of atmospheric particles plays a major role during DEs. In the dust samples, Ca(2+), Cl(-), NO3 (-), and SO4 (2-) were the most abundant ions and Ca(2+) alone accounted for 22 % of the total ionic mass, while during haze event, the concentrations of secondary aerosols species, viz., NO3 (-), SO4 (2-), and NH4 (+), were 3.6, 3.3, and 5.1 times higher than the normal days. During Diwali, SO4 (2-) concentration (17.8 μg m(-3)) was highest followed by NO3 (-), K(+), and Cl(-) while the Holi samples were strongly enriched with Cl(-) and K(+) which together made up 32.7 % of the total water-soluble ions. The ion balances indicate that the haze samples were acidic. On the other hand, Holi, Diwali, and DE samples were enriched with cations. The carbonaceous aerosol shows strong variation with the highest concentration during Holi followed by haze, Diwali, DEs, and NDs. However, the secondary organic carbon concentration follows the order haze > DEs > Diwali > Holi > NDs. The scanning electron microscope/EDX results indicate that KCl and carbon-rich particles were more dominant during Holi and haze events while DE samples were enriched with particles of crustal origin.

BIASES IN CASTNET FILTER PACK RESULTS ASSOCIATED WITH SAMPLING PROTOCOL

EPA Science Inventory

In the current study, single filter weekly (w) results are compared with weekly results aggregated from day and night (dn) weekly samples. Comparisons of the two sampling protocols for all major constituents (SO42-, NO3-, NH4+, HNO3, and SO2) show median bias (MB) of < 5 nmol m-3...

The impacts of firework burning at the Chinese Spring Festival on air quality: insights of tracers, source evolution and aging processes

NASA Astrophysics Data System (ADS)

Kong, S. F.; Li, L.; Li, X. X.; Yin, Y.; Chen, K.; Liu, D. T.; Yuan, L.; Zhang, Y. J.; Shan, Y. P.; Ji, Y. Q.

2015-02-01

To understand the impact of firework-burning (FW) particles on air quality and human health during the winter haze period, 39 elements, 10 water-soluble ions and 8 fractions of carbonaceous species in atmospheric PM2.5 in Nanjing were investigated during the 2014 Chinese Spring Festival (SF). Serious regional haze pollution persisted throughout the entire sampling period, with PM2.5 averaging at 113 ± 69 μg m-3 and visibility at 4.8 ± 3.2 km. The holiday effect led to almost all the chemical species decreasing during the SF, except for Al, K, Ba and Sr which were related to FW. The source contributions of coal combustion, vehicle emission and road dust decreased dramatically, whereas FW contributed to about half of the PM2.5 during the SF period. The intensive emission of FW particles on New Year's Eve accounted for 60.1% of the PM2.5. Fireworks also obviously modified the chemical compositions of PM2.5, with 39.3% contributed by increased organic matter, followed by steadily increased loadings of secondary inorganic ions. The aging processes of the FW particles lasted for about 4 days reflected by the variations of Ba, Sr, NH4+, NO3-, SO42- and K+, characterized by heterogeneous reactions of SO2 and NOx on crustal materials directly from FW, the replacement of Cl- by NO3- and SO42-, coating of NO3- and SO42- on soot, formation of secondary organic aerosols and metal-catalyzed formation of NO3- and SO42- at higher relative humidity. During aging, the main contributors to the extinction coefficient shifted from elemental carbon and organic matter to ammonium sulfate. The particles raised higher cancer risk of 1.62 × 10-6 by heavy metals (especially for Cd and As). This study provided detailed composition data and first comprehensive analysis of the aging processes of FW particles during the serious haze pollution period and their potential impact on human health.

Anaerobic methane oxidation may be more prevalent in surface soils than was originally thought

NASA Astrophysics Data System (ADS)

Gauthier, Mathieu; Bradley, Robert L.; Šimek, Miloslav

2013-04-01

Anaerobic oxidation of methane (CH4) (AOM) is a process that was first reported to occur in deep anoxic marine sediments. In this environment, CH4 is oxidized with sulphate (SO42-) as the terminal electron acceptor. It is mediated by a syntrophic consortium formed by SO42- reducing bacteria and anaerobic CH4 oxidizing Archaea, or by the latter alone. Since this landmark discovery, AOM was found to occur in other environments including freshwater lake sediments and water columns, mud volcanoes, landfill leachate, deep buried Holocene sediments and hydrocarbon contaminated aquifers. All of these situations are very specific and point to AOM as being primarily occurring in highly reducing conditions. Thus, observations of AOM in surface soils with fluctuating REDOX conditions are relatively scarce, although a few independent studies have reported AOM in surface peatlands as well as in a forest soil. Furthermore, AOM may follow different pathways, such as via the coupled oxidation of CH4 and reduction of manganese (Mn(IV)) or iron (Fe(III)), or by a lone denitrifying species that converts nitrite to nitric oxide in order to generate O2 that is then used internally to oxidize CH4. Thus, the goal of our study was to determine whether AOM is more prevalent than was thought in hydromorphic surface soils across different environments, and whether the addition of NO3- or SO4= as alternative electron acceptors may stimulate the process. We collected samples from 3 peatland soils in Scotland, 2 acid-sulphate soils in Finland, and shore sediments of 15 drained fish ponds in the Czech Republic. Subsamples were incubated in the absence of O2 and amended with either NO3-, SO42-, or left unamended (control). The net flux of CH4 and CO2 were assessed by gas chromatography after 2, 20, 40 and 60 days. We also used a 13C-CH4 isotope dilution technique to determine gross production and consumption rates of CH4. We detected AOM in all of our soils, with oxidation rates ranging between 0.001 and 37.28 nmol g-1 day-1, suggesting that AOM may be more ubiquitous than was originally thought. On the other hand, no clear patterns emerged as to the effects of NO3- or SO42- amendments on this process.

Atlas of absorption lines from 0 to 17 900 cm(-1)

NASA Technical Reports Server (NTRS)

Park, J. H.; Rothman, L. S.; Rinsland, C. P.; Smith, M. A. H.; Richardson, D. J.; Larsen, J. C.

1981-01-01

Plots of absorption line strength versus line position for wavenumbers from 0 to 17,900 cm(-1) are shown for 20 atmospheric gases (H2O, CO2, O3, N2O, CO, CH4, O2, NO, SO2, NO2, NH3, HNO3, OH, HF, HCl, HBr, HI, ClO, OCS, H2CO). Also shown are similar plots of lower-state energy values for adsorption lines for the strongly adsorbing atmospheric gases (H2O, CO2, O3, and CH4) for wavenumbers from 0 to 5000 cm(-1).

Effect of the electronegativity on the electrosorption selectivity of anions during capacitive deionization.

PubMed

Sun, Zhumei; Chai, Liyuan; Liu, Mingshi; Shu, Yude; Li, Qingzhu; Wang, Yunyan; Qiu, Dingfan

2018-03-01

The effect of electronegativity on the electrosorption selectivity of anions during capacitive deionization was investigated via a combination of experimental and theoretical studies. A model was developed based on chemical thermodynamics and the classic Stern's model to reveal the role of the anode potential and to describe electrosorption selectivity behavior during capacitive deionization. The effects of the anode potential on the adsorption of Cl - and ReO 4 - were studied and the obtained data were used to validate the model. Using the validated model, the effects of the anode potential and electronegativity of various anions, including Cl - , ReO 4 - , SO 4 2- and NO 3 - were assessed. The experimental results for the electrosorption of Cl - and ReO 4 - corresponded well with the developed model. The electrosorption capacity demonstrates a logarithmic relationship with the anode potential. The model showed that the electronegativity significantly affects the selectivity. In a mixed Cl - , ReO 4 - , SO 4 2- and NO 3 - solution, ReO 4 - was preferentially adsorbed over the other three anions, and the following selectivity was exhibited: ReO 4 -  > NO 3 -  > Cl -  > SO 4 2- . The results showed that the effect of flow rates on the electrosorption selectivity can be considered negligible when the flow rates are higher than 112 mL min -1 . The anions selectivity can be further enhanced by increasing the anode potential, and electrosorption selectivity is no appreciable decline after 6 experiments. Copyright © 2017 Elsevier Ltd. All rights reserved.

Further insights into the kinetics of thermal decomposition during continuous cooling.

PubMed

Liavitskaya, Tatsiana; Guigo, Nathanaël; Sbirrazzuoli, Nicolas; Vyazovkin, Sergey

2017-07-26

Following the previous work (Phys. Chem. Chem. Phys., 2016, 18, 32021), this study continues to investigate the intriguing phenomenon of thermal decomposition during continuous cooling. The phenomenon can be detected and its kinetics can be measured by means of thermogravimetric analysis (TGA). The kinetics of the thermal decomposition of ammonium nitrate (NH 4 NO 3 ), nickel oxalate (NiC 2 O 4 ), and lithium sulfate monohydrate (Li 2 SO 4 ·H 2 O) have been measured upon heating and cooling and analyzed by means of the isoconversional methodology. The results have confirmed the hypothesis that the respective kinetics should be similar for single-step processes (NH 4 NO 3 decomposition) but different for multi-step ones (NiC 2 O 4 decomposition and Li 2 SO 4 ·H 2 O dehydration). It has been discovered that the differences in the kinetics can be either quantitative or qualitative. Physical insights into the nature of the differences have been proposed.

Sulfur resistance of Ce-Mn/TiO2 catalysts for low-temperature NH3–SCR

PubMed Central

Yang, Wenjing; Cui, Shitong; Street, Jason; Luo, Yan

2018-01-01

Ce-Mn/TiO2 catalyst prepared using a simple impregnation method demonstrated a better low-temperature selective catalytic reduction of NO with NH3 (NH3–SCR) activity in comparison with the sol-gel method. The Ce-Mn/TiO2 catalyst loading with 20% Ce had the best low-temperature activity and achieved a NO conversion rate higher than 90% at 140–260°C with a 99.7% NO conversion rate at 180°C. The Ce-Mn/TiO2 catalyst only had a 6% NO conversion rate decrease after 100 ppm of SO2 was added to the stream. When SO2 was removed from the stream, the catalyst was able to recover completely. The crystal structure, morphology, textural properties and valence state of the metals involving the novel catalysts were investigated using X-ray diffraction, N2 adsorption and desorption analysis, X-ray photoelectron spectroscopy, scanning electron microscopy and energy dispersive spectroscopy, respectively. The decrease of NH3–SCR performance in the presence of 100 ppm SO2 was due to the decrease of the surface area, change of the pore structure, the decrease of Ce4+ and Mn4+ concentration and the formation of the sulfur phase chemicals which blocked the active sites and changed the valence status of the elements. PMID:29657791

Sulfur resistance of Ce-Mn/TiO2 catalysts for low-temperature NH3-SCR

NASA Astrophysics Data System (ADS)

Xu, Quan; Yang, Wenjing; Cui, Shitong; Street, Jason; Luo, Yan

2018-03-01

Ce-Mn/TiO2 catalyst prepared using a simple impregnation method demonstrated a better low-temperature selective catalytic reduction of NO with NH3 (NH3-SCR) activity in comparison with the sol-gel method. The Ce-Mn/TiO2 catalyst loading with 20% Ce had the best low-temperature activity and achieved a NO conversion rate higher than 90% at 140-260°C with a 99.7% NO conversion rate at 180°C. The Ce-Mn/TiO2 catalyst only had a 6% NO conversion rate decrease after 100 ppm of SO2 was added to the stream. When SO2 was removed from the stream, the catalyst was able to recover completely. The crystal structure, morphology, textural properties and valence state of the metals involving the novel catalysts were investigated using X-ray diffraction, N2 adsorption and desorption analysis, X-ray photoelectron spectroscopy, scanning electron microscopy and energy dispersive spectroscopy, respectively. The decrease of NH3-SCR performance in the presence of 100 ppm SO2 was due to the decrease of the surface area, change of the pore structure, the decrease of Ce4+ and Mn4+ concentration and the formation of the sulfur phase chemicals which blocked the active sites and changed the valence status of the elements.

Novel dry-desulfurization process using Ca(OH)2/fly ash sorbent in a circulating fluidized bed.

PubMed

Matsushima, Norihiko; Li, Yan; Nishioka, Masateru; Sadakata, Masayoshi; Qi, Haiying; Xu, Xuchang

2004-12-15

A dry-desulfurization process using Ca(OH)2/fly ash sorbent and a circulating fluidized bed (CFB) was developed. Its aim was to achieve high SO2 removal efficiency without humidification and production of CaSO4 as the main byproduct. The CaSO4 produced could be used to treat alkalized soil. An 83% SO2 removal rate was demonstrated, and a byproduct with a high CaSO4 content was produced through baghouse ash. These results indicated that this process could remove SO2 in flue gas with a high efficiency under dry conditions and simultaneously produce soil amendment. It was shown that NO and NO2 enhanced the SO2 removal rate markedly and that NO2 increased the amount of CaSO4 in the final product more than NO. These results confirmed that the significant effects of NO and NO2 on the SO2 removal rate were due to chain reactions that occurred under favorable conditions. The amount of baghouse ash produced increased as the reaction progressed, indicating that discharge of unreacted Ca(OH)2 from the reactor was suppressed. Hence, unreacted Ca(OH)2 had a long residence time in the CFB, resulting in a high SO2 removal rate. It was also found that 350 degrees C is the optimum reaction temperature for dry desulfurization in the range tested (320-380 degrees C).

Ship-based MAX-DOAS measurements of tropospheric NO2, SO2, and HCHO distribution along the Yangtze River

NASA Astrophysics Data System (ADS)

Hong, Qianqian; Liu, Cheng; Chan, Ka Lok; Hu, Qihou; Xie, Zhouqing; Liu, Haoran; Si, Fuqi; Liu, Jianguo

2018-04-01

In this paper, we present ship-based Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) measurements of tropospheric trace gases' distribution along the Yangtze River during winter 2015. The measurements were performed along the Yangtze River between Shanghai and Wuhan, covering major industrial areas in eastern China. Tropospheric vertical column densities (VCDs) of nitrogen dioxide (NO2), sulfur dioxide (SO2), and formaldehyde (HCHO) were retrieved using the air mass factor calculated by the radiative transfer model. Enhanced tropospheric NO2 and SO2 VCDs were detected over downwind areas of industrial zones over the Yangtze River. In addition, spatial distributions of atmospheric pollutants are strongly affected by meteorological conditions; i.e., positive correlations were found between concentration of pollutants and wind speed over these areas, indicating strong influence of transportation of pollutants from high-emission upwind areas along the Yangtze River. Comparison of tropospheric NO2 VCDs between ship-based MAX-DOAS and Ozone Monitoring Instrument (OMI) satellite observations shows good agreement with each other, with a Pearson correlation coefficient (R) of 0.82. In this study, the NO2 / SO2 ratio was used to estimate the relative contributions of industrial sources and vehicle emissions to ambient NO2 levels. Analysis results of the NO2 / SO2 ratio show a higher contribution of industrial NO2 emissions in Jiangsu Province, while NO2 levels in Jiangxi and Hubei provinces are mainly related to vehicle emissions. These results indicate that different pollution control strategies should be applied in different provinces. In addition, multiple linear regression analysis of ambient carbon monoxide (CO) and odd oxygen (Ox) indicated that the primary emission and secondary formation of HCHO contribute 54.4 ± 3.7 % and 39.3 ± 4.3 % to the ambient HCHO, respectively. The largest contribution from primary emissions in winter suggested that photochemically induced secondary formation of HCHO is reduced due to lower solar irradiance in winter. Our findings provide an improved understanding of major pollution sources along the eastern part of the Yangtze River which are useful for designing specific air pollution control policies.

Analysis of Nitrogen Dioxide and Sulphur Dioxide in Lima, Peru: Trends and Seasonal Variations

NASA Astrophysics Data System (ADS)

Pacsi, S.; Rappenglueck, B.

2007-12-01

This research was carried out to show a general analysis of the monthly and yearly variation (1996-2002) and the tendency of the nitrogen dioxide (NO2) and sulfur dioxide (SO2) for the 5 stations of the air quality network of Lima. The SO2 and NO2 concentrations were measured by the Dirección General de Salud Ambiental (DIGESA), using the active sampling method and the chemical analysis has been determined by Turbidimetry and Colorimetry for the SO2 and NO2 respectively. The monthly average variation (1996-2001) of SO2 in the Lima Center station has a small annual range (32,4 mikrograms/m3) with maximum values in autumn (April) and minimum in winter (June). The NO2 presents a higher annual range (128,2 mikrograms/m3) and its minimum values occur in the summer and the maximum in spring. The annual averages analysis (2000-2002) of the air quality monitoring network of Lima shows that the SO2 and NO2 values are maximum in the Lima Center station and exceed the Peruvian air quality standard (ECAs) in 30% and 75% respectively. The yearly variation (1996-2001) in the Lima Center station show an increasing tendency in the SO2 (significant) and NO2 (not significant) values, which indicates the critical level of the air quality in Lima, therefore the implementation of the air pollution control programs is urgent.

Dimethylsulfide/cloud condensation nuclei/climate system - Relevant size-resolved measurements of the chemical and physical properties of atmospheric aerosol particles

NASA Technical Reports Server (NTRS)

Quinn, P. K.; Covert, D. S.; Bates, T. S.; Kapustin, V. N.; Ramsey-Bell, D. C.; Mcinnes, L. M.

1993-01-01

The mass and number relationships occurring within the atmospheric dimethylsulfide/cloud condensation nuclei (CCN)/climate system, using simultaneous measurements of particulate phase mass size distributions of nss SO4(2-), methanesulfonic acid (MSA), and NH4(+); number size distributions of particles having diameters between 0.02 and 9.6 microns; CCN concentrations at a supersaturation of 0.3 percent; relative humidity; and temperature, obtained for the northeastern Pacific Ocean in April and May 1991. Based on these measurements, particulate nss SO4(2-), MSA, and NH4(+) mass appeared to be correlated with both particle effective surface area and number in the accumulation mode size range (0.16 to 0.5 micron). No correlations were found in the size range below 0.16 micron. A correlation was also found between nss SO4(2-) mass and the CCN number concentration, such that a doubling of the SO4(2-) mass corresponded to a 40 percent increase in the CCN number concentration. However, no correlation was found between MSA mass and CCN concentration.

Inorganic chemistry: Direct syntheses from pure liquid SO3 and from trivalent and pentavalent nitrogen derivatives

NASA Technical Reports Server (NTRS)

Vandorpe, B.; Heubel, J.

1977-01-01

From pure liquid SO3 direct synthesis reactions were carried out with N2O5, NO2Cl, NOCl which yielded N2O54SO3, 3SO3, 2SO3-NO2Cl2SO3-NOCl2SO3 and NOCl2SO3, the latter being obtained for the first time in the pure state. In all cases the crystallized product was obtained by separating the constituents of the mixture and then going through a single viscous liquid phase.

Uptake of HNO3 on aviation kerosene and aircraft engine soot: influences of H2O or/and H2SO4.

PubMed

Loukhovitskaya, Ekaterina E; Talukdar, Ranajit K; Ravishankara, A R

2013-06-13

The uptake of HNO3 on aviation kerosene soot (TC-1 soot) was studied in the absence and presence of water vapor at 295 and 243 K. The influence of H2SO4 coating of the TC-1 soot surface on HNO3 uptake was also investigated. Only reversible uptake of HNO3 was observed. HONO and NO2, potential products of reactive uptake of HNO3, were not observed under any conditions studied here. The uptake of nitric acid increased slightly with relative humidity (RH). Coating of the TC-1 soot surface with sulfuric acid decreased the uptake of HNO3 and did not lead to displacement of H2SO4 from the soot surface. A limited set of measurements was carried out on soot generated by aircraft engine combustor (E-soot) with results similar to those on TC-1 soot. The influence of water on HNO3 uptake on E-soot appeared to be more pronounced than on TC-1 soot. Our results suggest that HNO3 loss in the upper troposphere due to soot is not significant except perhaps in aircraft exhaust plumes. Our results also suggest that HNO3 is not converted to either NO2 or HONO upon its uptake on soot in the atmosphere.

Secondary Inorganic Soluble Aerosol in Hong Kong: Continuous Measurements, Formation Mechanism Discussion and Improvement of an Observation-Based Model to Study Control Strategies

NASA Astrophysics Data System (ADS)

Xue, Jian

Work in this thesis focuses on half-hourly or hourly measurements of PM2.5 secondary inorganic aerosols (SIA) in two locations in Hong Kong (HK) using a continuous system, PILS (Particle-into-Liquid System) coupled to two ion chromatographs. The high-resolution data sets allow the examination of SIA temporal dynamics in the scale of hours that the filter-based approach is incapable of providing. (1) Impacts of local emissions, regional transports and their interactions on chemical composition and concentrations of PM2.5 SIA and other ionic species were investigated at the Hong Kong University of Science and Technology (HKUST), a receptor site, under three synoptic conditions. (2) Chemical compositions and size characteristics of ionic species were investigated at Tung Chung, a new town area located in the Southwest part of HK. The sampling period was from 17 to 26 December 2009, covering both normal conditions and an aerosol episode. The three major secondary inorganic ions, SO42, NH4+ and NO 3-, accounted for 47 +/- 6% of PM2.5 mass. Further examination of size characteristics of NO3 - shows that fine mode NO3- is more likely to occur in environments when the fine particles are less acidic and the sea-salt aerosol contributions are low. (3) The ionic chemical composition of PM2.5 and meteorological parameters (e.g., temperature, RH) obtained at the HKUST site under all three different synoptic conditions are input into Aerosol Inorganic Model (AIM-III) for estimation of in situ pH through calculation of H+ amount and aerosol liquid water content (LWC). The second part of this thesis work is to improve an observation-based model (OBAMAP) for SIA, which was first developed by Dr. Zibing Yuan (2006) to evaluate the sensitivity of formation of nitrate ad sulfate to changes in the emissions of their precursors (i.e., NOx, SO2, and VOCs). The improvement work includes incorporating updated chemical mechanisms, thermodynamic equilibrium for gas-aerosol phase apportionment and size distribution of SIA. The new OBM for SIA is applied to hourly gaseous and particulate composition data measured during a wintertime pollution episode encountered in Tung Chung for probing effectiveness of different precursor control strategies. The OBM is demonstrated to provide a relatively simple and cost-effective tool for analyzing the increasing database of high time resolution measurements of VOCs and major aerosol ionic species. In this thesis, we propose a new production regime of SO4 2- in which oxidation of S(IV) is dominated by NO 2 and O3 in the aqueous phase. Simulated with a simplified version of OBAMAP, it is shown elevation of NOx favors productions of SO42- in this regime, especially under high-SO 2 conditions. We then study the importance of NO2-derived and O3-derived SO42- during haze episodes in PRD and during winter at urban/suburban locations in PRD. Our findings reveal these two pathways account for >70% of SO42- productions. Since production of NO2-derived SO4 2- is independent on solar actinic fluxes while production by other pathways is, NO2-derived SO42- plays a more important role under low solar actinic fluxes conditions, even during the night time. In addition, it is noted that high levels of NO2-derived SO42- can only be expected under high-SO2 conditions (like in PRD) because level of atmospheric SO2 is the limiting parameter. (Abstract shortened by UMI.)

Cloud condensation nucleation activities of calcium carbonate and its atmospheric ageing products.

PubMed

Tang, M J; Whitehead, J; Davidson, N M; Pope, F D; Alfarra, M R; McFiggans, G; Kalberer, M

2015-12-28

Aerosol particles can serve as cloud condensation nuclei (CCN) to form cloud droplets, and its composition is a main factor governing whether an aerosol particle is an effective CCN. Pure mineral dust particles are poor CCN; however, changes in chemical composition of mineral dust aerosol particles, due to heterogeneous reactions with reactive trace gases in the troposphere, can modify their CCN properties. In this study we investigated the CCN activities of CaCO3 (as a surrogate for mineral dust) and its six atmospheric ageing products: Ca(NO3)2, CaCl2, CaSO4, Ca(CH3SO3)2, Ca(HCOO)2, and Ca(CH3COO)2. CaCO3 has a very low CCN activity with a hygroscopicity parameter (κ) of 0.001-0.003. The CCN activities of its potential atmospheric ageing products are significantly higher. For example, we determined that Ca(NO3)2, CaCl2 and Ca(HCOO)2 have κ values of ∼0.50, similar to that of (NH4)2SO4. Ca(CH3COO)2 has slightly lower CCN activity with a κ value of ∼0.40, and the κ value of CaSO4 is around 0.02. We further show that exposure of CaCO3 particles to N2O5 at 0% relative humidity (RH) significantly enhances their CCN activity, with κ values increasing to around 0.02-0.04. Within the experimental uncertainties, it appears that the variation in exposure to N2O5 from ∼550 to 15,000 ppbv s does not change the CCN activities of aged CaCO3 particles. This observation indicates that the CaCO3 surface may be already saturated at the shortest exposure. We also discussed the atmospheric implications of our study, and suggested that the rate of change in CCN activities of mineral dust particles in the troposphere is important to determine their roles in cloud formation.

Pb4(BO3)2(SO4) and Pb2[(BO2)(OH)](SO4): New lead(II) borate-sulfate mixed-anion compounds with two types of 3D network structures

NASA Astrophysics Data System (ADS)

Ruan, Ting-Ting; Wang, Wen-Wen; Hu, Chun-Li; Xu, Xiang; Mao, Jiang-Gao

2018-04-01

Two new lead(II) borate-sulfate mixed-anion compounds, namely, Pb4(BO3)2(SO4) and Pb2[(BO2)(OH)](SO4), have been prepared by using high-temperature melt method or hydrothermal reaction. These compounds exhibit two different types of 3D structures composed of the same anionic units of BO3 triangles and SO4 tetrahedra which are interconnected by lead(II) cations. In Pb4(BO3)2(SO4), the lead(II) ions are bridged by borate anions into 3D [Pb4(BO3)2]2+ architectures with 1D tunnels of 8-member rings along the a-axis, which are filled by the sulfate anions. In Pb2[(BO2)(OH)](SO4), the lead(II) ions are interconnected by borate and sulfate anions into 2D Pb-B-O and Pb-S-O layers parallel to the ab plane, respectively, and these layers are further condensed into the 3D lead(II) borate-sulfate framework. TGA and DSC studies indicate that Pb4(BO3)2(SO4) is congruently melting with a melting point of 689 °C whereas Pb2[(BO2)(OH)](SO4) decomposes at approximately 335 °C. UV/Vis/NIR optical diffuse reflectance spectrum measurements reveal the optical band gaps of 4.03 and 4.08 eV for Pb4(BO3)2(SO4) and Pb2[(BO2)(OH)](SO4), respectively. Furthermore, the electronic structures of Pb4(BO3)2(SO4) have also been calculated.

Measurements of Rural Sulfur Dioxide and Particle Sulfate: Analysis of CASTNet Data, 1987 through 1996.

PubMed

Baumgardner, Ralph E; Isil, Selma S; Bowser, Jon J; Fitzgerald, Kelley M

1999-11-01

The Clean Air Status and Trends Network (CASTNet) was implemented by the U.S. Environmental Protection Agency (EPA) in 1991 in response to Title IX of the Clean Air Amendments of 1990, which mandated the deployment of a national ambient air monitoring network to track progress of the implementation of emission reduction programs in terms of deposition, air quality, and changes to affected ecosystems. CASTNet evolved from the National Dry Deposition Network (NDDN). CASTNet currently consists of 45 sites in the eastern United States and 28 sites in the West. Each site measures sulfur dioxide (SO 2 ), nitric acid (HNO 3 ), particle sulfate (SO 4 = ), particle nitrate (NO 3 - ), and ozone. Nineteen sites collect precipitation samples. NDDN/CASTNet uses a uniform set of site-selection criteria which provides the data user with consistent measures to compare each site. These criteria also ensure that, to the extent possible, CASTNet sites are located away from local emission sources. This paper presents an analysis of SO 2 and SO 4 = concentration data collected from 1987 through 1996 at rural NDDN/CASTNet sites. Annual and seasonal variability is examined. Gradients of SO 2 and SO 4 = are discussed. The variability of the atmospheric mix of SO 2 and SO 4 = is explored spatially and seasonally. Data from CASTNet are also compared to SO 2 and SO 4 = data from concurrent monitoring studies in rural areas.

Selection of metal oxides in the preparation of rice husk ash (RHA)/CaO sorbent for simultaneous SO2 and NO removal.

PubMed

Dahlan, Irvan; Lee, Keat Teong; Kamaruddin, Azlina Harun; Mohamed, Abdul Rahman

2009-07-30

In this work, the removal of SO(2) and NO from simulated flue gas from combustion process was investigated in a fixed-bed reactor using rice husk ash (RHA)/CaO-based sorbent. Various metal precursors were used in order to select the best metal impregnated over RHA/CaO sorbents. The results showed that RHA/CaO sorbents impregnated with CeO(2) had the highest sorption capacity among other impregnated metal oxides for the simultaneous removal of SO(2) and NO. Infrared spectroscopic results indicated the formation of both sulfate (SO(4)(2-)) and nitrate (NO(3)(-)) species due to the catalytic role played by CeO(2). Apart from that, the catalytic activity of the RHA/CaO/CeO(2) sorbent was found to be closely related to its physical properties (specific surface area, total pore volume and average pore diameter).

The State of Ambient Air Quality in Two Ugandan Cities: A Pilot Cross-Sectional Spatial Assessment

PubMed Central

Kirenga, Bruce J.; Meng, Qingyu; van Gemert, Frederik; Aanyu-Tukamuhebwa, Hellen; Chavannes, Niels; Katamba, Achilles; Obai, Gerald; van der Molen, Thys; Schwander, Stephan; Mohsenin, Vahid

2015-01-01

Air pollution is one of the leading global public health risks but its magnitude in many developing countries’ cities is not known. We aimed to measure the concentration of particulate matter with aerodynamic diameter <2.5 µm (PM2.5), nitrogen dioxide (NO2), sulfur dioxide (SO2), and ozone (O3) pollutants in two Ugandan cities (Kampala and Jinja). PM2.5, O3, temperature and humidity were measured with real-time monitors, while NO2 and SO2 were measured with diffusion tubes. We found that the mean concentrations of the air pollutants PM2.5, NO2, SO2 and O3 were 132.1 μg/m3, 24.9 µg/m3, 3.7 µg/m3 and 11.4 μg/m3, respectively. The mean PM2.5 concentration is 5.3 times the World Health Organization (WHO) cut-off limits while the NO2, SO2 and O3 concentrations are below WHO cut-off limits. PM2.5 levels were higher in Kampala than in Jinja (138.6 μg/m3 vs. 99.3 μg/m3) and at industrial than residential sites (152.6 μg/m3 vs. 120.5 μg/m3) but residential sites with unpaved roads also had high PM2.5 concentrations (152.6 μg/m3). In conclusion, air pollutant concentrations in Kampala and Jinja in Uganda are dangerously high. Long-term studies are needed to characterize air pollution levels during all seasons, to assess related public health impacts, and explore mitigation approaches. PMID:26184273

Distributions of SO2 and NO2 in the lower atmosphere of an industrial area in Bhutan.

PubMed

Subba, Jas Raj; Thammakhet, Chongdee; Thavarungkul, Panote; Kanatharana, Proespichaya

2016-12-05

Two important air pollutants, sulfur dioxide (SO 2 ) and nitrogen dioxide (NO 2 ), were sampled and monitored in the spring season in the biggest industrial area of Bhutan. Field measurements of SO 2 and NO 2 were performed using standard colorimetric methods, and air samples were collected using an active sampling technique. Sampling sites were selected to cover all the potential catchment areas like settlements, staff quarters, shops and schools. The main objective of this sampling work was to see the distribution of these two pollutants from the source of emission (small scale industries) and to obtain and establish a baseline data. The active sampler was first tested and validated in a laboratory using liquid and gas standards of SO 2 and NO 2 . Good linearity from 0.050 to 1.0 µg mL -1 for SO 2 and from 0.010 to 1.0 µg mL -1 for NO 2 were obtained (R 2 > 0.99) with limits of detection of 30 and 50 ng mL -1 for SO 2 and NO 2 , respectively. Daylong sampling was done at selected sites with a range of distances away from the sources of emission. The ambient concentration of SO 2 and NO 2 were in the range of 0.45-4.46 and 0.56-5.68 µg m -3 , respectively.

The sensitivity of direct faecal examination, direct faecal flotation, modified centrifugal faecal flotation and centrifugal sedimentation/flotation in the diagnosis of canine spirocercosis.

PubMed

Christie, J; Schwan, E V; Bodenstein, L L; Sommerville, J E M; van der Merwe, L L

2011-06-01

Several faecal examination techniques have shown variable sensitivity in demonstrating Spirocerca lupi (S. lupi) eggs. The objective of this study was to determine which faecal examination technique, including a novel modified centrifugal flotation technique, was most sensitive to diagnose spirocercosis. Ten coproscopic examinations were performed on faeces collected from 33 dogs confirmed endoscopically to have spirocercosis. The tests included a direct faecal examination, a faecal sedimentation/flotation test, 4 direct faecal flotations and 4 modified faecal centrifugal flotations. These latter 2 flotation tests utilised 4 different faecal flotation solutions: NaNO3 (SG 1.22), MgSO4 (SG 1.29), ZnSO4 (SG 1.30) and sugar (SG 1.27). The sensitivity of the tests ranged between 42% and 67%, with the NaNO3 solution showing the highest sensitivity in both the direct and modified-centrifugal flotations. The modified NaNO3 centrifugal method ranked 1st with the highest mean egg count (45.24 +/- 83), and was superior (i.e. higher egg count) and significantly different (P < 0.05) compared with the routine saturated sugar, ZnSO4 and MgSO4 flotation methods. The routine NaNO3 flotation method was also superior and significantly different (P < 0.05) compared with the routine ZnSO4 and MgSO4 flotation methods. Fifteen per cent (n = 5) of dogs had neoplastic oesophageal nodules and a further 18% (n = 6) had both neoplastic and non-neoplastic nodules. S. lupi eggs were demonstrated in 40% of dogs with neoplastic nodules only and 72.9% of the dogs with non-neoplastic nodules. The mean egg count in the non-neoplastic group (61) was statistically greater (P = 0.02) than that of the neoplastic group (1). The results show that faecal examination using a NaNO3 solution is the most sensitive in the diagnosis of spirocercosis. The modified centrifugal flotation faecal method using this solution has the highest egg count. The study also found that dogs with neoplastic nodules shed significantly fewer eggs than dogs with non-neoplastic nodules.

Augmenting computer networks

NASA Technical Reports Server (NTRS)

Bokhari, S. H.; Raza, A. D.

1984-01-01

Three methods of augmenting computer networks by adding at most one link per processor are discussed: (1) A tree of N nodes may be augmented such that the resulting graph has diameter no greater than 4log sub 2((N+2)/3)-2. Thi O(N(3)) algorithm can be applied to any spanning tree of a connected graph to reduce the diameter of that graph to O(log N); (2) Given a binary tree T and a chain C of N nodes each, C may be augmented to produce C so that T is a subgraph of C. This algorithm is O(N) and may be used to produce augmented chains or rings that have diameter no greater than 2log sub 2((N+2)/3) and are planar; (3) Any rectangular two-dimensional 4 (8) nearest neighbor array of size N = 2(k) may be augmented so that it can emulate a single step shuffle-exchange network of size N/2 in 3(t) time steps.

Polymorphism in Bi2(SO4)3

NASA Astrophysics Data System (ADS)

Subban, Chinmayee V.; Rousse, Gwenaëlle; Courty, Matthieu; Barboux, Philippe; Tarascon, Jean-Marie

2014-12-01

A new polymorph of Bi2(SO4)3 was prepared by reaction of LiBiO2 with H2SO4 and its crystal structure was solved from X-ray powder diffraction. This new polymorph crystallizes in C2/c space group with lattice parameters a = 17.3383(3) Å, b = 6.77803(12) Å, c = 8.30978(13) Å, β = 101.4300(12)°. Bi2(SO4)3 presents a layered structure made of SO4 sulfate groups and signs of stereochemically active Bi3+ lone pairs. The new Bi2(SO4)3 absorbs water to form Bi2(H2O)2(SO4)2(OH)2 through an intermediate Bi2O(OH)2SO4 phase, and the transition is reversible when heated under vacuum.

Notes on Search, Detection and Localization Modeling. Revision 4

DTIC Science & Technology

1990-10-01

2, --- , k where the subregions are relabeled so that the following order relation holds: pi/6 1 > p 2!6 2 > ... > pr65 and where k is chosen so... Interfaces ," Operations Research, Vol. 19, No.3, pp 559-586, 1971. 15. Coggins, P.B., "Detection Probability Computations for Random Search of an

Trends in atmospheric ammonium concentrations in relation to atmospheric sulfate and local agriculture.

PubMed

Kelly, Victoria R; Lovett, Gary M; Weathers, Kathleen C; Likens, Gene E

2005-06-01

Ammonium (NH(4)(+)) concentrations in air and precipitation at the Institute of Ecosystem Studies (IES) in southeastern New York, USA declined over an 11-year period from 1988 to 1999, but increased from 1999 to 2001. These trends in particulate NH(4)(+) correlated well with trends in particulate SO(4)(2-) over the 1988-2001 period. The NH(4)(+) trends were not as well correlated with local cattle and milk production, which declined continuously throughout the period. This suggests that regional transport of SO(4)(2-) may have a greater impact on concentrations of NH(4)(+) and subsequent deposition than local agricultural emissions of NH(3). Ammonium concentrations in precipitation correlated significantly with precipitation SO(4)(2-) concentrations for the 1984-2001 period although NH(4)(+) in precipitation increased after 1999 and SO(4)(2-) in precipitation continued to decline after 1999. The correlation between NH(4)(+) and SO(4)(2-) was stronger for particulates than for precipitation. Particulate NH(4)(+) concentrations were also correlated with particulate SO(4)(2-) concentrations at 31 of 35 eastern U.S. CASTNet sites that had at least 10 years of data. Air concentrations of NH(4)(+) and SO(4)(2-) were more strongly correlated at the sites that were located within an agricultural landscape than in forested sites. At most of the sites there was either no trend or a decrease in NH(4)(+) dry deposition during the 1988-2001 period. The sites that showed an increasing trend in NH(4)(+) dry deposition were generally located in the southeastern U.S. The results of this study suggest that, in the northeastern U.S., air concentrations of NH(4)(+) and subsequent deposition may be more closely linked to SO(4)(2-) and thus SO(2) emissions than with NH(3) emissions. These results also suggest that reductions in S emissions have reduced NH(4)(+) transport to and NH(4)(+)-N deposition in the Northeast.

Characterization of trace gases measured over Alberta oil sands mining operations: 76 speciated C2-C10 volatile organic compounds (VOCs), CO2, CH4, CO, NO, NO2, NOy, O3 and SO2

NASA Astrophysics Data System (ADS)

Simpson, I. J.; Blake, N. J.; Barletta, B.; Diskin, G. S.; Fuelberg, H. E.; Gorham, K.; Huey, L. G.; Meinardi, S.; Rowland, F. S.; Vay, S. A.; Weinheimer, A. J.; Yang, M.; Blake, D. R.

2010-12-01

Oil sands comprise 30% of the world's oil reserves and the crude oil reserves in Canada's oil sands deposits are second only to Saudi Arabia. The extraction and processing of oil sands is much more challenging than for light sweet crude oils because of the high viscosity of the bitumen contained within the oil sands and because the bitumen is mixed with sand and contains chemical impurities such as sulphur. Despite these challenges, the importance of oil sands is increasing in the energy market. To our best knowledge this is the first peer-reviewed study to characterize volatile organic compounds (VOCs) emitted from Alberta's oil sands mining sites. We present high-precision gas chromatography measurements of 76 speciated C2-C10 VOCs (alkanes, alkenes, alkynes, cycloalkanes, aromatics, monoterpenes, oxygenated hydrocarbons, halocarbons and sulphur compounds) in 17 boundary layer air samples collected over surface mining operations in northeast Alberta on 10 July 2008, using the NASA DC-8 airborne laboratory as a research platform. In addition to the VOCs, we present simultaneous measurements of CO2, CH4, CO, NO, NO2, NOy, O3 and SO2, which were measured in situ aboard the DC-8. Carbon dioxide, CH4, CO, NO, NO2, NOy, SO2 and 53 VOCs (e.g., non-methane hydrocarbons, halocarbons, sulphur species) showed clear statistical enhancements (1.1-397×) over the oil sands compared to local background values and, with the exception of CO, were greater over the oil sands than at any other time during the flight. Twenty halocarbons (e.g., CFCs, HFCs, halons, brominated species) either were not enhanced or were minimally enhanced (<10%) over the oil sands. Ozone levels remained low because of titration by NO, and three VOCs (propyne, furan, MTBE) remained below their 3 pptv detection limit throughout the flight. Based on their correlations with one another, the compounds emitted by the oil sands industry fell into two groups: (1) evaporative emissions from the oil sands and its products and/or from the diluent used to lower the viscosity of the extracted bitumen (i.e., C4-C9 alkanes, C5-C6 cycloalkanes, C6-C8 aromatics), together with CO; and (2) emissions associated with the mining effort, such as upgraders (i.e., CO2, CO, CH4, NO, NO2, NOy, SO2, C2-C4 alkanes, C2-C4 alkenes, C9 aromatics, short-lived solvents such as C2Cl4 and C2HCl3, and longer-lived species such as HCFC-22 and HCFC-142b). Prominent in the second group, SO2 and NO were remarkably enhanced over the oil sands, with maximum mixing ratios of 38.7 ppbv and 5.0 ppbv, or 383× and 319× the local background, respectively. These SO2 levels are comparable to maximum values measured in heavily polluted megacities such as Mexico City and are attributed to coke combustion. By contrast, relatively poor correlations between CH4, ethane and propane suggest low levels of natural gas leakage despite its heavy use at the surface mining sites. Instead the elevated CH4 levels are attributed to methanogenic tailings pond emissions. In addition to the emission of many trace gases, the natural drawdown of OCS by vegetation was absent above the surface mining operations, presumably because of the widespread land disturbance. Unexpectedly, the mixing ratios of α-pinene and β-pinene were much greater over the oil sands (up to 217 pptv and 610 pptv, respectively) than over vegetation in the background boundary layer (20±7 pptv and 84±24 pptv, respectively), and the pinenes correlated well with several industrial tracers that were elevated in the oil sands plumes. Because so few independent measurements from the oil sands mining industry exist, this study provides an important initial characterization of trace gas emissions from oil sands surface mining operations.

Formation of Gd coordination polymer with 1D chains mediated by Bronsted acidic ionic liquids

NASA Astrophysics Data System (ADS)

Luo, Qianqian; Han, Ying; Lin, Hechun; Zhang, Yuanyuan; Duan, Chungang; Peng, Hui

2017-03-01

One dimensional coordination polymer Gd[(SO4)(NO3)(C2H6SO)2] (1) is prepared through the mediation of Bronsted acid ionic liquid, which crystallized in the monoclinic space of C2/c. In this polymer, adjacent Gd atoms are linked by two SO42- ions to generate a 1-D chain, and all oxygen atoms in SO42- groups are connected to three nearest Gd atoms in μ3:η1:η1:η2 fashion. Gd, S and N from SO42- and NO3- are precisely coplanar. The planar is coordinated by a pair of DMSO molecules, which is parallel and linked by hydrogen bonding to form a three-dimensional supramolecular network. Magnetic susceptibility measurement of 1 reveals weak antiferromagnetic interactions between the Gd (III) ions. It exhibits relatively large magneto-caloric effect with -ΔSm=28.8 J Kg-1 K-1 for ΔH=7 T.

Acid etching of titanium for bonding with veneering composite resins.

PubMed

Ban, Seiji; Taniki, Toshio; Sato, Hideo; Kono, Hiroshi; Iwaya, Yukari; Miyamoto, Motoharu

2006-06-01

Commercially pure titanium (cpTi) was etched using three concentrated acids: 18% HCl, 43% H3PO4, and 48% H2SO4. The bond strengths between five types of veneering composite resin and eight cpTi treatments (involving combinations of sandblasting, acid etching in 48% H2SO4, and vacuum firing) were determined before and after 10,000 and 20,000 thermal cycles. There were no significant differences in the bond strength of resin to cpTi after etching in 48% H2SO4 at 90 degrees C for 15 minutes, at 60 degrees C for 15, 30, or 60 minutes, and after sandblasting with and without vacuum firing (p > 0.05); moreover, these treatments yielded the highest values. As for vacuum firing, it had no significant effect on resin bond strength to cpTi before or after 10,000 and 20,000 thermal cycles. We therefore concluded that acid etching in concentrated H2SO4 is a simple and effective surface modification method of titanium for bonding to veneering composite resins.

Vibrational spectroscopic characterization of the sulphate-halide mineral sulphohalite - implications for evaporites.

PubMed

Frost, Ray L; Scholz, Ricardo; López, Andrés; Theiss, Frederick L

2014-12-10

The mineral sulphohalite - Na6(SO4)2FCl is a rare sodium halogen sulphate and occurs associated with evaporitic deposits. Sulphohalite formation is important in saline evaporites and in pipe scales. Sulphohalite is an anhydrous sulphate-halide with an apparent variable anion ratio of formula Na6(SO4)2FCl. Such a formula with oxyanions lends itself to vibrational spectroscopy. The Raman band at 1003cm(-1) is assigned to the (SO4)(2-) ν1 symmetric stretching mode. Shoulders to this band are found at 997 and 1010cm(-1). The low intensity Raman bands at 1128, 1120 and even 1132cm(-1) are attributed to the (SO4)(2-) ν3 antisymmetric stretching vibrations. Two symmetric sulphate stretching modes are observed indicating at least at the molecular level the non-equivalence of the sulphate ions in the sulphohalite structure. The Raman bands at 635 and 624cm(-1) are assigned to the ν4 SO4(2-) bending modes. The ν2 (SO4)(2-) bending modes are observed at 460 and 494cm(-1). The observation of multiple bands supports the concept of a reduction in symmetry of the sulphate anion from Td to C3v or even C2v. No evidence of bands attributable to the halide ions was found. Copyright © 2014 Elsevier B.V. All rights reserved.

Application of an online ion-chromatography-based instrument for gradient flux measurements of speciated nitrogen and sulfur

NASA Astrophysics Data System (ADS)

Rumsey, Ian C.; Walker, John T.

2016-06-01

The dry component of total nitrogen and sulfur atmospheric deposition remains uncertain. The lack of measurements of sufficient chemical speciation and temporal extent make it difficult to develop accurate mass budgets and sufficient process level detail is not available to improve current air-surface exchange models. Over the past decade, significant advances have been made in the development of continuous air sampling measurement techniques, resulting with instruments of sufficient sensitivity and temporal resolution to directly quantify air-surface exchange of nitrogen and sulfur compounds. However, their applicability is generally restricted to only one or a few of the compounds within the deposition budget. Here, the performance of the Monitor for AeRosols and GAses in ambient air (MARGA 2S), a commercially available online ion-chromatography-based analyzer is characterized for the first time as applied for air-surface exchange measurements of HNO3, NH3, NH4+, NO3-, SO2 and SO42-. Analytical accuracy and precision are assessed under field conditions. Chemical concentrations gradient precision are determined at the same sampling site. Flux uncertainty measured by the aerodynamic gradient method is determined for a representative 3-week period in fall 2012 over a grass field. Analytical precision and chemical concentration gradient precision were found to compare favorably in comparison to previous studies. During the 3-week period, percentages of hourly chemical concentration gradients greater than the corresponding chemical concentration gradient detection limit were 86, 42, 82, 73, 74 and 69 % for NH3, NH4+, HNO3, NO3-, SO2 and SO42-, respectively. As expected, percentages were lowest for aerosol species, owing to their relatively low deposition velocities and correspondingly smaller gradients relative to gas phase species. Relative hourly median flux uncertainties were 31, 121, 42, 43, 67 and 56 % for NH3, NH4+, HNO3, NO3-, SO2 and SO42-, respectively. Flux uncertainty is dominated by uncertainty in the chemical concentrations gradients during the day but uncertainty in the chemical concentration gradients and transfer velocity are of the same order at night. Results show the instrument is sufficiently precise for flux gradient applications.

Stream water chemistry in watersheds receiving different atmospheric inputs of H+, NH4+, NO3-, and SO42-1

USGS Publications Warehouse

Stottlemyer, R.

1997-01-01

Weekly precipitation and stream water samples were collected from small watersheds in Denali National Park, Alaska, the Fraser Experimental Forest, Colorado, Isle Royale National Park, Michigan, and the Calumet watershed on the south shore of Lake Superior, Michigan. The objective was to determine if stream water chemistry at the mouth and upstream stations reflected precipitation chemistry across a range of atmospheric inputs of H+, NH4+, NO3-, and SO42-. Volume-weighted precipitation H+, NH4+, NO3-, and SO42- concentrations varied 4 to 8 fold with concentrations highest at Calumet and lowest in Denali. Stream water chemistry varied among sites, but did not reflect precipitation chemistry. The Denali watershed, Rock Creek, had the lowest precipitation NO3- and SO42- concentrations, but the highest stream water NO3and SO42- concentrations. Among sites, the ratio of mean monthly upstream NO3- concentration to precipitation NO3- concentration declined (p 90 percent inputs) across inputs ranging from 0.12 to > 6 kg N ha-1 y-1. Factors possibly accounting for the weak or non-existent signal between stream water and precipitation ion concentrations include rapid modification of meltwater and precipitation chemistry by soil processes, and the presence of unfrozen soils which permits winter mineralization and nitrification to occur.

Aged particles derived from emissions of coal-fired power plants: The TERESA field results

PubMed Central

Kang, Choong-Min; Gupta, Tarun; Ruiz, Pablo A.; Wolfson, Jack M.; Ferguson, Stephen T.; Lawrence, Joy E.; Rohr, Annette C.; Godleski, John; Koutrakis, Petros

2013-01-01

The Toxicological Evaluation of Realistic Emissions Source Aerosols (TERESA) study was carried out at three US coal-fired power plants to investigate the potential toxicological effects of primary and photochemically aged (secondary) particles using in situ stack emissions. The exposure system designed successfully simulated chemical reactions that power plant emissions undergo in a plume during transport from the stack to receptor areas (e.g., urban areas). Test atmospheres developed for toxicological experiments included scenarios to simulate a sequence of atmospheric reactions that can occur in a plume: (1) primary emissions only; (2) H2SO4 aerosol from oxidation of SO2; (3) H2SO4 aerosol neutralized by gas-phase NH3; (4) neutralized H2SO4 with secondary organic aerosol (SOA) formed by the reaction of α-pinene with O3; and (5) three control scenarios excluding primary particles. The aged particle mass concentrations varied significantly from 43.8 to 257.1 μg/m3 with respect to scenario and power plant. The highest was found when oxidized aerosols were neutralized by gas-phase NH3 with added SOA. The mass concentration depended primarily on the ratio of SO2 to NOx (particularly NO) emissions, which was determined mainly by coal composition and emissions controls. Particulate sulfate (H2SO4 + neutralized sulfate) and organic carbon (OC) were major components of the aged particles with added SOA, whereas trace elements were present at very low concentrations. Physical and chemical properties of aged particles appear to be influenced by coal type, emissions controls and the particular atmospheric scenarios employed. PMID:20462390

Process for the removal of acid forming gases from exhaust gases and production of phosphoric acid

DOEpatents

Chang, Shih-Ger; Liu, David K.

1992-01-01

Exhaust gases are treated to remove NO or NO.sub.x and SO.sub.2 by contacting the gases with an aqueous emulsion or suspension of yellow phosphorous preferably in a wet scrubber. The addition of yellow phosphorous in the system induces the production of O.sub.3 which subsequently oxidizes NO to NO.sub.2. The resulting NO.sub.2 dissolves readily and can be reduced to form ammonium ions by dissolved SO.sub.2 under appropriate conditions. In a 20 acfm system, yellow phosphorous is oxidized to yield P.sub.2 O.sub.5 which picks up water to form H.sub.3 PO.sub.4 mists and can be collected as a valuable product. The pressure is not critical, and ambient pressures are used. Hot water temperatures are best, but economics suggest about 50.degree. C. The amount of yellow phosphorus used will vary with the composition of the exhaust gas, less than 3% for small concentrations of NO, and 10% or higher for concentrations above say 1000 ppm. Similarly, the pH will vary with the composition being treated, and it is adjusted with a suitable alkali. For mixtures of NO.sub.x and SO.sub.2, alkalis that are used for flue gas desulfurization are preferred. With this process, better than 90% of SO.sub.2 and NO in simulated flue gas can be removed. Stoichiometric ratios (P/NO) ranging between 0.6 and 1.5 were obtained.

Synthesis, structure, and properties of chromium(III) sulfates

NASA Astrophysics Data System (ADS)

Atkinson, Tom David; Fjellvåg, Helmer; Kjekshus, Arne

2004-11-01

Reactions between CrO 3 and 50- 95 wt% H2SO4 are studied at temperatures up to the boiling point of the acid. Depending on the H 2SO 4 concentration and synthesis temperature, Cr 2(SO 4) 3, CrH(SO 4) 2, (H 3O)[Cr(SO 4) 2], Cr 2(SO 4) 3·H 2SO 4·4H 2O (gross formula), and (H 5O 2)[Cr(H 2O) 2(SO 4) 2], are obtained as identified reaction products in addition to the incompletely characterized chromic-sulfuric acid. The Cr III-based sulfates are characterized by X-ray powder diffraction, thermogravimetric, and magnetic susceptibility measurements. The nuclear and magnetic structures of Cr 2(SO 4) 3 at 10 K are determined, the structure type of (H 3O)[Cr(SO 4) 2] is established, and the crystal structure of (H 5O 2)[Cr(H 2O) 2(SO 4) 2] is firmly stipulated. Magnetic susceptibility data suggest that the samples of CrH(SO 4) 2 are in a micro-crystalline rather than in an amorphous state. All Cr III-based sulfates synthesized in this study appear to undergo paramagnetic-to-antiferromagnetic transitions at around 10 K.

Seasonal variations in the major chemical species of snow at the South East Dome in Greenland

NASA Astrophysics Data System (ADS)

Oyabu, Ikumi; Matoba, Sumito; Yamasaki, Tetsuhide; Kadota, Moe; Iizuka, Yoshinori

2016-03-01

We analyze snow-pit samples collected in May 2015 at the South East Dome (SE Dome) on the Greenland ice sheet. The analysis includes high-resolution records of δD and δ18O, as well as the major ions, CH3SO3-, Cl-, NO3-, SO42-, Na+, NH4+, K+, Ma2+, and Ca2+. We find that the 3.55-m snow pit recorded temperature and aerosol proxies back to summer or autumn of 2014. This indicates a higher accumulation rate than those at other major drilling sites in Greenland. Due to this high accumulation rate, ion concentrations except Na+ are lower than those typical of the central Greenland ice sheet. Concerning seasonal variability, the Na+, Cl-, Ca2+, Mg2+, and NO3- vary similarly to other sites in Greenland, with the Na+ and Cl- peaking in winter to early spring, Ca2+ peaking in spring, Mg2+ peaking in winter to spring, and NO3- towards a peak in summer while showing smaller peaks in winter to spring. The NH4+ increased in spring, and SO42- increased in autumn to winter at SE Dome. On the other hand, the seasonal trend in the Cl-/Na+ ratio differs from those in the inland region. As we did not fully recover one seasonal cycle, some seasonal peaks may have been missed.

Air pollution in China: Status and spatiotemporal variations.

PubMed

Song, Congbo; Wu, Lin; Xie, Yaochen; He, Jianjun; Chen, Xi; Wang, Ting; Lin, Yingchao; Jin, Taosheng; Wang, Anxu; Liu, Yan; Dai, Qili; Liu, Baoshuang; Wang, Ya-Nan; Mao, Hongjun

2017-08-01

In recent years, China has experienced severe and persistent air pollution associated with rapid urbanization and climate change. Three years' time series (January 2014 to December 2016) concentrations data of air pollutants including particulate matter (PM 2.5 and PM 10 ) and gaseous pollutants (SO 2 , NO 2 , CO, and O 3 ) from over 1300 national air quality monitoring sites were studied to understand the severity of China's air pollution. In 2014 (2015, 2016), annual population-weighted-average (PWA) values in China were 65.8 (55.0, 50.7) μg m -3 for PM 2.5 , 107.8 (91.1, 85.7) μg m -3 for PM 10 , 54.8 (56.2, 57.2) μg m -3 for O 3 _8 h, 39.6 (33.3, 33.4) μg m -3 for NO 2 , 34.1 (26, 21.9) μg m -3 for SO 2 , 1.2 (1.1, 1.1) mg m -3 for CO, and 0.60 (0.59, 0.58) for PM 2.5 /PM 10 , respectively. In 2014 (2015, 2016), 7% (14%, 19%), 17% (27%, 34%), 51% (67%, 70%) and 88% (97%, 98%) of the population in China lived in areas that meet the level of annual PM 2.5 , PM 10 , NO 2 , and SO 2 standard metrics from Chinese Ambient Air Quality Standards-Grade II. The annual PWA concentrations of PM 2.5 , PM 10 , O 3 _8 h, NO 2 , SO 2 , CO in the Northern China are about 40.4%, 58.9%, 5.9%, 24.6%, 96.7%, and 38.1% higher than those in Southern China, respectively. Though the air quality has been improving recent years, PM 2.5 pollution in wintertime is worsening, especially in the Northern China. The complex air pollution caused by PM and O 3 (the third frequent major pollutant) is an emerging problem that threatens the public health, especially in Chinese mega-city clusters. NOx controls were more beneficial than SO 2 controls for improvement of annual PM air quality in the northern China, central, and southwest regions. Future epidemiologic studies are urgently required to estimate the health impacts associated with multi-pollutants exposure, and revise more scientific air quality index standards. Copyright © 2017 Elsevier Ltd. All rights reserved.

Syntheses, crystal structures and optical spectroscopy of Ln{sub 2}(SO{sub 4}){sub 3}.8H{sub 2}O (Ln=Ho, Tm) and Pr{sub 2}(SO{sub 4}){sub 3}.4H{sub 2}O

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kazmierczak, Karolina; Hoeppe, Henning A., E-mail: henning@ak-hoeppe.d

2011-05-15

The lanthanide sulphate octahydrates Ln{sub 2}(SO{sub 4}){sub 3}.8H{sub 2}O (Ln=Ho, Tm) and the respective tetrahydrate Pr{sub 2}(SO{sub 4}){sub 3}.4H{sub 2}O were obtained by evaporation of aqueous reaction mixtures of trivalent rare earth oxides and sulphuric acid at 300 K. Ln{sub 2}(SO{sub 4}){sub 3}.8H{sub 2}O (Ln=Ho, Tm) crystallise in space group C2/c (Z=4, a{sub Ho}=13.4421(4) A, b{sub Ho}=6.6745(2) A, c{sub Ho}=18.1642(5) A, {beta}{sub Ho}=102.006(1) A{sup 3} and a{sub Tm}=13.4118(14) A, b{sub Tm}=6.6402(6) A, c{sub Tm}=18.1040(16) A, {beta}{sub Tm}=101.980(8) A{sup 3}), Pr{sub 2}(SO{sub 4}){sub 3}.4H{sub 2}O adopts space group P2{sub 1}/n (a=13.051(3) A, b=7.2047(14) A, c=13.316(3) A, {beta}=92.55(3) A{sup 3}). The vibrationalmore » and optical spectra of Ho{sub 2}(SO{sub 4}){sub 3}.8H{sub 2}O and Pr{sub 2}(SO{sub 4}){sub 3}.4H{sub 2}O are also reported. -- Graphical abstract: In the lanthanide sulphate octahydrates the cations form slightly undulated layers. Between the layers are voids in which sulphate tetrahedra and water molecules are located. The holmium compound exhibits an Alexandrite effect. Display Omitted Highlights: {yields} Determination of the optimum conditions for the growth of single-crystals of Ln{sub 2}(SO{sub 4}){sub 3}.8H{sub 2}O (Ln=Ho, Tm) and Pr{sub 2}(SO{sub 4}){sub 3}.4H{sub 2}O. {yields} Single-crystal structure elucidation of Ln{sub 2}(SO{sub 4}){sub 3}.8H{sub 2}O (Ln=Ho, Tm) including hydrogen bonds. {yields} Single-crystal structure determination of Pr{sub 2}(SO{sub 4}){sub 3}.4H{sub 2}O including hydrogen bonds. {yields} UV-vis spectra of Ho{sub 2}(SO{sub 4}){sub 3}.8H{sub 2}O and Pr{sub 2}(SO{sub 4}){sub 3}.4H{sub 2}O recorded and interpreted: Assignation of bands and clarification of the Alexandrite effect of the Ho compound. {yields} IR and Raman spectra of Ln{sub 2}(SO{sub 4}){sub 3}.8H{sub 2}O (Ln=Ho, Tm) and Pr{sub 2}(SO{sub 4}){sub 3}.4H{sub 2}O recorded and interpreted.« less

Characteristics of concentrations and water-soluble inorganic ions in PM2.5 in Handan City, Hebei province, China

NASA Astrophysics Data System (ADS)

Meng, C. C.; Wang, L. T.; Zhang, F. F.; Wei, Z.; Ma, S. M.; Ma, X.; Yang, J.

2016-05-01

In order to explore the spatial, temporal, and chemical characteristics of fine particulate matter (PM2.5) pollution in Handan city, China, a comprehensive dataset including continuous online observations at four air quality monitoring stations in 2013 and 2014, and the concentrations of water-soluble inorganic ions (WSII) (NO3-, SO42 -, NH4+, Cl-, Na+, Mg2 +, K+, Ca2 +) in PM2.5 samples collected in four representative seasons in 2013 and 2014 are analyzed in this study. And the principal component analysis (PCA) method is applied to identify the source of WSII in Handan. Our results indicate that PM2.5 concentration decreased from 139.4 μg/m3 in 2013 to 116.0 μg/m3 in 2014 on annual average. Spatial variations of PM2.5 mass are not pronounced, indicating that PM2.5 is nearly evenly spread over the study area. The seasonal variations of PM2.5 concentration are significant, normally with 1.7 to 2.4 times higher in winter than in summer. The concentrations of TWSII (total water-soluble inorganic ions) remain relatively stable in two years, with annual averages of 63.1 μg/m3 in 2013 and 57.2 μg/m3 in 2014. SNA (SO42 -, NO3-, NH4+) dominates in the TWSII, accounting for ~ 87% of the TWSII. Similar to PM2.5, WSII exhibits obvious seasonal variations with higher concentrations in autumn and winter, lower in spring and summer. PM2.5 samples are acidic in spring, summer and autumn of 2013, while in winter of 2013 and all seasons of 2014, they are alkaline. SO42 -, NO3- are formed mainly through homogeneous reactions, heterogeneous reactions also exist in winter. Finally, the major sources of WSII in Handan are identified as the mixture of secondary origin, coal combustion, biomass burning (46.1%), dust sources (25.8%), and motor vehicle (12.3%).

New Insight into SO2 Poisoning and Regeneration of CeO2-WO3/TiO2 and V2O5-WO3/TiO2 Catalysts for Low-Temperature NH3-SCR.

PubMed

Xu, Liwen; Wang, Chizhong; Chang, Huazhen; Wu, Qingru; Zhang, Tao; Li, Junhua

2018-06-19

In this study, the poisoning effects of SO 2 on the V 2 O 5 -WO 3 /TiO 2 (1%VWTi) and CeO 2 -WO 3 /TiO 2 (5%CeWTi) selective catalytic reduction (SCR) catalysts were investigated in the presence of steam, and also the regeneration of deactivated catalysts was studied. After pretreating the catalysts in a flow of NH 3 + SO 2 + H 2 O + O 2 at 200 °C for 24 h, it was observed that the low-temperature SCR (LT-SCR) activity decreased significantly over the 1%VWTi and 5%CeWTi catalysts. For 1%VWTi, NH 4 HSO 4 (ABS) was the main product detected after the poisoning process. Both of NH 4 HSO 4 and cerium sulfate species were formed on the poisoned 5%CeWTi catalyst, indicating that SO 2 reacted with Ce 3+ /Ce 4+ , even in the presence of high concentration of NH 3 . The decrease of BET specific surface area, NO x adsorption capacity, the ratio of chemisorbed oxygen, and reducibility were responsible for the irreversible deactivation of the poisoned 5%CeWTi catalyst. Meanwhile, the LT-SCR activity could be recovered over the poisoned 1%VWTi after regeneration at 400 °C, but not for the 5%CeWTi catalyst. For industrial application, it is suggested that the regeneration process can be utilized for 1%VWTi catalysts after a period of time after NH 4 HSO 4 accumulated on the catalysts.

Amine templating effect absent in uranyl sulfates synthesized with 1,4-n-butyldiamine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jouffret, Laurent J., E-mail: ljouffret@nd.edu; Wylie, Ernest M.; Burns, Peter C.

2013-01-15

Two new uranyl sulfates, (C{sub 4}H{sub 14}N{sub 2})[(UO{sub 2}){sub 2}(SO{sub 4}){sub 3}(H{sub 2}O)]{center_dot}2H{sub 2}O (NDUS2) and (C{sub 4}H{sub 14}N{sub 2})[(UO{sub 2})(SO{sub 4}){sub 2}(H{sub 2}O)]{center_dot}2H{sub 2}O (NDUS3), were synthesized and their crystal structures determined. NDUS2 was obtained in highly acidic media heat-treated at 373 K and subsequently maintained at 278 K until crystals formed after two months. NDUS3 results from the degradation of NDUS2 over the course of a few days. NDUS2 and NDUS3 crystallize in the monoclinic space group P2{sub 1}/n, a=10.9075(4) A, b=10.4513(4) A, c=17.7881(7) A, {beta}=97.908(2) Degree-Sign , V=2008.52(13) A{sup 3}, Z=4, at 140 K and a=8.8570(4) A,more » b=7.3299(3) A, c=20.4260(9) A, {beta}=95.140(2) Degree-Sign , V=1320.74(10) A{sup 3}, Z=4, at 140 K, respectively. The compounds contain interlayer 1,4-n-butyldiammonium cations that charge-balance the anionic structural units. - Graphical abstract: Amine templating effect absent in uranyl sulfates synthesized with 1,4-diaminobutane, as shown by the synthesis of two new uranyl sulfates, (C{sub 4}H{sub 14}N{sub 2})[(UO{sub 2}){sub 2}(SO{sub 4}){sub 3}(H{sub 2}O)]{center_dot}2H{sub 2}O (NDUS2) and (C{sub 4}H{sub 14}N{sub 2})[(UO{sub 2})(SO{sub 4}){sub 2}(H{sub 2}O)]{center_dot}2H{sub 2}O (NDUS3). Highlights: Black-Right-Pointing-Pointer Two layered uranyl sulfates were synthesized. Black-Right-Pointing-Pointer Amine molecules are located in the interlayers of the compounds. Black-Right-Pointing-Pointer No templating effect of the amine was observed. Black-Right-Pointing-Pointer Amine molecules are only charge balancing cations in the structures.« less

Suppression of peatland methane emission by cumulative sulfate deposition in simulated acid rain

Treesearch

Nancy B. Dise; Elon S. Verry

2001-01-01

This field manipulation study tested the effect of weekly pulses of solutions of NH4NO3 and (NH4)2SO4 salts on the evolution of CH4 and N2O from peatland soils. Methane and nitrous oxide emission from a...

Solar Metal Sulfate-Ammonia Based Thermochemical Water Splitting Cycle for Hydrogen Production

NASA Technical Reports Server (NTRS)

T-Raissi, Ali (Inventor); Muradov, Nazim (Inventor); Huang, Cunping (Inventor)

2014-01-01

Two classes of hybrid/thermochemical water splitting processes for the production of hydrogen and oxygen have been proposed based on (1) metal sulfate-ammonia cycles (2) metal pyrosulfate-ammonia cycles. Methods and systems for a metal sulfate MSO.sub.4--NH3 cycle for producing H2 and O2 from a closed system including feeding an aqueous (NH3)(4)SO3 solution into a photoctalytic reactor to oxidize the aqueous (NH3)(4)SO3 into aqueous (NH3)(2)SO4 and reduce water to hydrogen, mixing the resulting aqueous (NH3)(2)SO4 with metal oxide (e.g. ZnO) to form a slurry, heating the slurry of aqueous (NH4)(2)SO4 and ZnO(s) in the low temperature reactor to produce a gaseous mixture of NH3 and H2O and solid ZnSO4(s), heating solid ZnSO4 at a high temperature reactor to produce a gaseous mixture of SO2 and O2 and solid product ZnO, mixing the gaseous mixture of SO2 and O2 with an NH3 and H2O stream in an absorber to form aqueous (NH4)(2)SO3 solution and separate O2 for aqueous solution, recycling the resultant solution back to the photoreactor and sending ZnO to mix with aqueous (NH4)(2)SO4 solution to close the water splitting cycle wherein gaseous H2 and O2 are the only products output from the closed ZnSO4--NH3 cycle.

The system K2Mg2(SO4)3 (langbeinite)-K2Ca2(SO4)3 (calcium-langbeinite)

USGS Publications Warehouse

Morey, G.W.; Rowe, J.J.; Fournier, R.O.

1964-01-01

The join between the compositions K2Mg2(SO4)3 and K2Ca2(SO4)3 was studied by means of high-temperature equilibrium quenching techniques and by means of a heating stage mounted on an X-ray diffractometer. Complete solid solution exists in the system, but at 25??C members of the solid solution series are isometric only in the composition range 0-73??5 wt. per cent K2Ca2(SO4)3. At compositions richer in K2Ca2(SO4)3 than 73??5 wt. per cent, members of the series are optically biaxial. At higher temperatures members of the solid solution series are isometric at successively more calcium-rich compositions and pure K2Ca2(SO4)3 is isometric above about 200 ?? 2??C. The system is not binary, as mixtures richer in K2Ca2(SO4)3 than 42 wt. per cent decompose with the formation of liquid and CaSO4. ?? 1964.

Factors and sources influencing ionic composition of atmospheric condensate during winter season in lower troposphere over Delhi, India.

PubMed

Kumar, Pawan; Yadav, Sudesh

2013-03-01

Atmospheric condensate (AC) and rainwater samples were collected during 2010-2011 winter season from Delhi and characterized for major cations and anions. The observed order of abundance of cations and anions in AC samples was NH (4) (+)  > Ca(2+) > Na(+) > K(+) > Mg(2+) and HCO (3) (-)  > SO (4) (2-)  > Cl(-) > NO (2) (-)  > NO (3) (-)  > F(-), respectively. All samples were alkaline in nature and Σ (cation)/Σ (anion) ratio was found to be close to one. NH (4) (+) emissions followed by Ca(2+) and Mg(2+) were largely responsible for neutralization of acidity caused by high NO( x ) and SO(2) emissions from vehicles and thermal power plants in the region. Interestingly, AC samples show low nitrate content compared with its precursor nitrite, which is commonly reversed in case of rainwater. It could be due to (1) slow light-mediated oxidation of HONO; (2) larger emission of NO(2) and temperature inversion conditions entrapping them; and (3) formation and dissociation of ammonium nitrite, which seems to be possible as both carry close correlation in our data set. Principal component analysis indicated three factors (marine mixed with biomass burning, anthropogenic and terrestrial, and carbonates) for all ionic species. Significantly higher sulfate/nitrate ratio indicates greater anthropogenic contributions in AC samples compared with rainwater. Compared with rainwater, AC samples show higher abundance of all ionic species except SO(4), NO(3), and Ca suggesting inclusion of these ions by wash out process during rain events. Ionic composition and related variations in AC and rainwater samples indicate that two represent different processes in time and space coordinates. AC represents the near-surface interaction whereas rainwater chemistry is indicative of regional patterns. AC could be a suitable way to understand atmospheric water interactions with gas and solid particle species in the lower atmosphere.

Citric acid production using immobilized conidia of Aspergillus niger TMB 2022

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsay, S.S.; To, K.Y.

1987-02-20

Conidia of Aspergillus niger TMB 2022 were immobilized in calcium alginate for the production of citric acid. A 1-ml condidia suspension containing ca. 2.32 x 10/sup 8/ conidia were entrapped into sodium alginate solution in order to prepare 3% Ca-alginate (w/v) gel bead. Immobilized conidia were inoculated into productive medium containing 14% sucrose, 0.25% (NH/sub 4/)/sub 2/CO/sub 3/, 0.25% KH/sub 2/PO/sub 4/, and 0.025% MgSO/sub 4/.7H/sub 2/O with addition of 0.06 mg/l CuSO/sub 4/.5H/sub 2/O, 0.25 mg/l ZnCl/sub 2/, 1.3 mg/l FeCl/sub 3/.6H/sub 2/O, pH 3.8, and incubated at 35 degrees C for 13 days by surface culture to producemore » 61.53 g/l anhydrous citric acid. Under the same conditions with a batchwise culture, it was found that immobilized conidia could maintain a longer period for citric acid production (31 days): over 70 g/l anhydrous citric acid from runs No. 2-4, with the maximum yield for anhydrous citric acid reaching 77.02 g/l for run No. 2. In contrast, free conidia maintained a shorter acid-producing phase, circa 17 days; the maximum yield for anhydrous citric acid was 71.07 g/l for run No. 2 but dropped quickly as the run number increased. 14 references.« less

Trace Chemistry

NASA Technical Reports Server (NTRS)

Radhakrishnan, Krishnan; Whitefield, Philip

1999-01-01

The goals of the trace chemistry group were to identify the processes relevant to aerosol and aerosol precursor formation occurring within aircraft gas turbine engines; that is, within the combustor, turbine, and nozzle. The topics of discussion focused on whether the chemistry of aerosol formation is homogeneous or heterogeneous; what species are important for aerosol and aerosol precursor formation; what modeling/theoretical activities to pursue; what experiments to carry out that both support modeling activities and elucidate fundamental processes; and the role of particulates in aerosol and aerosol precursor formation. The consensus of the group was that attention should be focused on SO2, SO3, and aerosols. Of immediate concern is the measurement of the concentration of the species SO3, SO2, H2SO4 OH, HO2, H2O2, O, NO, NO2, HONO, HNO3, CO, and CO2 and particulates in various engines, both those currently in use and those in development. The recommendation was that concentration measurements should be made at both the combustor exit and the engine exit. At each location the above species were classified into one of four categories of decreasing importance, Priority I through IV, as follows: Combustor exit: Priority I species - SO3:SO2 ratio, SO3, SO2, and particulates; Priority II species: OH and O; Priority III species - NO and NO2; and Priority IV species - CO and CO2. For the Engine exit: Priority I species - SO3:SO2 ratio, SO3, SO2,H2SO4, and particulates; Priority II species: OH,HO2, H2O2, and O; Priority III species - NO, NO2, HONO, and HNO3; and Priority IV species - CO and CO2. Table I summarizes the anticipated concentration range of each of these species. For particulate matter, the quantities of interest are the number density, size distribution, and composition. In order to provide data for validating multidimensional reacting flow models, it would be desirable to make 2-D, time-resolved measurements of the concentrations of the above species and, in addition, of the pressure, temperature, and velocity. A near term goal of the experimental program should be to confirm the nonlinear effects of sulfur speciation, and if present, to provide an explanation for them. It is also desirable to examine if the particulate matter retains any sulfur. The recommendation is to examine the effects on SOx production of variations in fuel-bound sulfur and aromatic content (which may affect the amount of particulates formed). These experiments should help us to understand if there is a coupling between particulate formation and SO, concentration. Similarly, any coupling with NOx can be examined either by introducing NOx into the combustion air or by using fuel-bound nitrogen. Also of immediate urgency is the need to establish and validate a detailed mechanism for sulfur oxidation/aerosol formation, whose chemistry is concluded to be homogeneous, because there is not enough surface area for heterogeneous effects. It is envisaged that this work will involve both experimental and theoretical programs. The experimental work will require, in addition to the measurements described above, fundamental studies in devices such as flow reactors and shock tubes. Complementing this effort should be modeling and theoretical activities. One impediment to the successful modeling of sulfur oxidation is the lack of reliable data for thermodynamic and transport properties for several species, such as aqueous nitric acid, sulfur oxides, and sulfuric acid. Quantum mechanical calculations are recommended as a convenient means of deriving values for these properties. Such calculations would also help establish rate constants for several important reactions for which experimental measurements are inherently fraught with uncertainty. Efforts to implement sufficiently detailed chemistry into computational fluid dynamic codes should be continued. Zero- and one-dimensional flow models are also useful vehicles for elucidating the minimal set of species and reactions that must be included in two- and three-dimensional modeling studies.

Decolorization and mineralization of Allura Red AC aqueous solutions by electrochemical advanced oxidation processes.

PubMed

Thiam, Abdoulaye; Sirés, Ignasi; Garrido, José A; Rodríguez, Rosa M; Brillas, Enric

2015-06-15

The decolorization and mineralization of solutions containing 230 mg L(-1) of the food azo dye Allura Red AC at pH 3.0 have been studied upon treatment by electrochemical oxidation with electrogenerated H2O2 (EO-H2O2), electro-Fenton (EF) and photoelectro-Fenton (PEF). Experiments were performed with a stirred tank reactor containing a boron-doped diamond (BDD) or Pt anode and an air-diffusion cathode to generate H2O2. The main oxidants were hydroxyl radicals formed at the anode surface from water oxidation and in the bulk from Fenton's reaction between H2O2 and added Fe(2+). The oxidation ability increased in the sequence EO-H2O2 < EF < PEF and faster degradation was always obtained using BDD. PEF process with BDD yielded almost total mineralization following similar trends in SO4(2-), ClO4(-) and NO3(-) media, whereas in Cl(-) medium, mineralization was inhibited by the formation of recalcitrant chloroderivatives. GC-MS analysis confirmed the cleavage of the −N=N− bond with formation of two main aromatics in SO4(2-) medium and three chloroaromatics in Cl(-) solutions. The effective oxidation of final oxalic and oxamic acids by BDD along with the photolysis of Fe(III)-oxalate species by UVA light accounted for the superiority of PEF with BDD. NH4(+), NO3(-) and SO4(2-) ions were released during the mineralization. Copyright © 2015 Elsevier B.V. All rights reserved.

Both sides now: the chemistry of clouds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schwartz, S.E.

1984-01-01

Two complementary approaches to the study of the oxidation of SO/sub 2/ and NO/sub x/ to sulfuric and nitric acids as it occurs in liquid-water clouds are presented. The first approach relies upon laboratory determination of fundamental physical and chemical properties and evaluation of rates of dissolution and reaction for representative reagent concentrations and physical situations. The second approach consists of measuring concentrations of relevant reagent and product species and other pertinent quantities in and about clouds and of drawing inferences from these measurements about the rate and extent of processes responsible for establishing cloudwater composition. Based on laboratory studiesmore » the following inferences may be drawn: aqueous-phase oxidation of SO/sub 2/ by H/sub 2/O/sub 2/ or O/sub 3/ is sufficiently rapid to contribute to cloudwater acidity for representative concentrations of these oxidants; however, the rate of the O/sub 3/ reaction decreases strongly with decreasing pH and is of relatively little importance below about pH 4.5. Despite strong thermochemical driving force for oxidation of NO/sub 2/ to nitric acid in cloudwater, this reaction appears to be negligibly slow for representative concentrations of NO/sub 2/, largely because of the low Henry's law solubility of this species in water. These inferences gain support from field measurements of the composition of liquid water stratiform clouds at various locations in the eastern United States, which indicate that the fractional uptake of SO/sub 2/ (as SO/sub 4//sup =/) by cloudwater is frequently high, whereas a corresponding high fractional uptake of NO/sub x/ as NO/sub 3//sup -/ is never observed. A mutual exclusivity of gaseous SO/sub 2/ and dissolved H/sub 2/O/sub 2/ in clouds supports the inference that reaction of these species in clouds is rapid and represents a major process for cloudwater acidification. 143 references, 35 figures, 2 tables.« less

Missing SO2 oxidant in the coastal atmosphere? - observations from high-resolution measurements of OH and atmospheric sulfur compounds

NASA Astrophysics Data System (ADS)

Berresheim, H.; Adam, M.; Monahan, C.; O'Dowd, C.; Plane, J. M. C.; Bohn, B.; Rohrer, F.

2014-11-01

Diurnal and seasonal variations of gaseous sulfuric acid (H2SO4) and methane sulfonic acid (MSA) were measured in NE Atlantic air at the Mace Head atmospheric research station during the years 2010 and 2011. The measurements utilized selected-ion chemical ionization mass spectrometry (SI/CIMS) with a detection limit for both compounds of 4.3 × 104 cm-3 at 5 min signal integration. The H2SO4 and MSA gas-phase concentrations were analyzed in conjunction with the condensational sink for both compounds derived from 3 nm to 10 μm (aerodynamic diameter) aerosol size distributions. Accommodation coefficients of 1.0 for H2SO4 and 0.12 for MSA were assumed, leading to estimated atmospheric lifetimes on the order of 7 and 25 min, respectively. With the SI/CIMS instrument in OH measurement mode alternating between OH signal and background (non-OH) signal, evidence was obtained for the presence of one or more unknown oxidants of SO2 in addition to OH. Depending on the nature of the oxidant(s), its ambient concentration may be enhanced in the CIMS inlet system by additional production. The apparent unknown SO2 oxidant was additionally confirmed by direct measurements of SO2 in conjunction with calculated H2SO4 concentrations. The calculated H2SO4 concentrations were consistently lower than the measured concentrations by a factor of 4.7 ± 2.4 when considering the oxidation of SO2 by OH as the only source of H2SO4. Both the OH and the background signal were also observed to increase significantly during daytime aerosol nucleation events, independent of the ozone photolysis frequency, J(O1D), and were followed by peaks in both H2SO4 and MSA concentrations. This suggests a strong relation between the unknown oxidant(s), OH chemistry, and the atmospheric photolysis and photooxidation of biogenic iodine compounds. As to the identity of the atmospheric SO2 oxidant(s), we have been able to exclude ClO, BrO, IO, and OIO as possible candidates based on {ab initio} calculations. Nevertheless, IO could contribute significantly to the observed CIMS background signal. A detailed analysis of this CIMS background signal in context with recently published kinetic data currently suggests that Criegee intermediates (CIs) produced from ozonolysis of alkenes play no significant role for SO2 oxidation in the marine atmosphere at Mace Head. On the other hand, SO2 oxidation by small CIs such as CH2OO produced photolytically or possibly in the photochemical degradation of methane is consistent with our observations. In addition, H2SO4 formation from dimethyl sulfide oxidation via SO3 as an intermediate instead of SO2 also appears to be a viable explanation. Both pathways need to be further explored.

Phyllanthus muellerianus and C6H15NO3 synergistic effects on 0.5 M H2SO4-immersed steel-reinforced concrete: Implication for clean corrosion-protection of wind energy structures in industrial environment

NASA Astrophysics Data System (ADS)

Okeniyi, Joshua Olusegun; Omotosho, Olugbenga Adeshola; Popoola, Abimbola Patricia Idowu; Loto, Cleophas Akintoye

2016-07-01

This paper investigates Phyllanthus muellerianus leaf-extract and C6H15NO3 (triethanolamine: TEA) synergistic effects on reinforcing-steel corrosion-inhibition and the compressive-strength of steel-reinforced concrete immersed in 0.5 M H2SO4. This is to assess suitability of the synergistic admixture usage for wind-energy steel-reinforced concrete structures designed for industrial environments. Steel-reinforced concrete specimens were admixed with individual and synergistic designs of Phyllanthus muellerianus leaf-extract and C6H15NO3 admixtures and immersed in the 0.5 M H2SO4. Electrochemical monitoring of corrosion potential, as per ASTM C876-91 R99, and corrosion current were obtained and statistically analysed, as per ASTM G16-95 R04, for modelling noise resistance. Post-immersion compressive-strength testing then followed, as per ASTM C39/C39M-03, for detailing the admixture effect on load-bearing strength of the steel-reinforced concrete specimens. Results showed that while individual Phyllanthus muellerianus leaf-extract concentrations exhibited better inhibition-efficiency performance than C6H15NO3, synergistic additions of C6H15NO3 to Phyllanthus muellerianus leaf-extract improved steel-rebar corrosion-inhibition. Thus, 6 g Phyllanthus muellerianus + 2 g C6H15NO3 synergistically improved inhibition-efficiency to η = 84.17%, from η = 55.28% by the optimal chemical or from η = 74.72% by the optimal plant-extract admixtures. The study also established that improved compressive strength of steel-reinforced concrete with acceptable inhibition of the steel-rebar corrosion could be attained through optimal combination of the Phyllanthus muellerianus leaf-extract and C6H15NO3 admixtures.

Interaction of copper with dinitrogen tetroxide in 1-butyl-3-methylimidazolium-based ionic liquids.

PubMed

Morozov, I V; Deeva, E B; Glazunova, T Yu; Troyanov, S I; Guseinov, F I; Kustov, L M

2017-03-27

Ionic liquids that are stable toward oxidation and nitration and are based on the 1-n-butyl-3-methylimidazolium cation (BMIm + ) can be used as solvents and reaction media for copper dissolution in liquid dinitrogen tetraoxide N 2 O 4 . The ionic liquid not only favors the dissociation of N 2 O 4 into NO + and NO 3 - , but also takes part in the formation of different crystalline products. Thus, NO[BF 4 ], NO[Cu(NO 3 ) 3 ] and (BMIm) 2 [Cu 2 (CF 3 COO) 6 ] were prepared using (BMIm)A, A - = [BF 4 ] - , (CF 3 SO 2 ) 2 N - , CF 3 COO - , respectively. The formation of a certain product is determined by the nature of the anion A - and the relative solubility of the reaction products in the ionic liquid. Crystals of NO[BF 4 ] were also prepared directly from a mixture of N 2 O 4 and BMImBF 4 . According to XRD single-crystal structure analysis, the structure of NO[BF 4 ] consists of tetrahedral [BF 4 ] - anions and nitrosonium NO + cations; the formation of these ions prove the heterolytic dissociation of N 2 O 4 dissolved in the ionic liquid. The crystal structure of the earlier unknown binuclear copper trifluoroacetate (BMIm) 2 [Cu 2 (CF 3 COO) 6 ] were determined by X-ray diffraction. The peculiarity of this dimer compared to the majority of known dimeric copper(ii) carboxylates is the unusually long CuCu distance (3.15 Å), with Cu(ii) ions demonstrating an atypical coordination of a distorted trigonal bipyramid formed by five O atoms of five trifluoroacetate groups.

Thermodynamic properties and crystal structure refinement of ferricopiapite, coquimbite, rhomboclase, and Fe2(SO4)3(H2O)5

USGS Publications Warehouse

Majzlan, J.; Navrotsky, A.; McCleskey, R. Blaine; Alpers, Charles N.

2006-01-01

Enthalpies of formation of ferricopiapite [nominally Fe4.67(SO4)6(OH)2 (H2O)20]. coquimbite [Fe2(SO4)3(H2O)9], rhomboclase [(H3O)Fe(SO4)2 (H2O)3], and Fe2(SO4)3(H2O)5 were measured by acid (5 N HCl) solution calorimetry. The samples were characterized by wet chemical analyses and synchrotron powder X-ray diffraction (XRD). The refinement of XRD patterns gave lattice parameters, atomic positions, thermal factors, and occupancies of the sites. The calculated formulae differ slightly from the nominal compositions: Fe4.78(SO4)6 (OH)2.34(H2O)20.71 (ferricopiapite), (Fe1.47Al0.53)(SO4)3 (H2O)9.65 (coquimbite), (H3O)1.34Fe(SO4)2.17 (H2O)3.06 (rhomboclase), and Fe2(SO4)3 (H2O)5.03. All thermodynamic data are given per mole of these formulae. The measured standard enthalpies (in kJ/mol) of formation from the elements (crystalline Fe, Al, S, and ideal gases O2 and H2) at T = 298.15 K are -4115.8??4.1 [Fe2(SO4)3 (H2O)5.03], -12045.1??9.2 (ferricopiapite), -5738.4??3.3 (coquimbite), and -3201.1??2.6 (rhomboclase). Standard entropy (S??) was estimated as a sum of entropies of oxide, hydroxide, and sulfate components. The estimated S?? (in J/mol.K) values for the iron sulfates are 488.2 [Fe2(SO4)3 (H2O)5.03], 1449.2 (ferricopiapite), 638.3 (coquimbite), and 380.1 (rhomboclase). The calculated Gibbs free energies of formation (in kJ/mol) are -3499.7??4.2 [Fe2(SO4)3 (H2O)5.03], -10089.8??9.3 (ferricopiapite), -4845.6??3.3 (coquimbite), and -2688.0??2.7 (rhomboclase). These results combined with other available thermodynamic data allow construction of mineral stability diagrams in the FeIII2(SO4)3-FeII SO4-H2O system. One such diagram is provided, indicating that the order of stability of ferric sulfate minerals with decreasing pH in the range of 1.5 to -0.5 is: hydronium jarosite, ferricopiapite, and rhomboclase. ?? 2006 E. Schweizerbart'sche Verlagsbuchhandlung.

Study of the reaction of atomic oxygen with aerosols

NASA Technical Reports Server (NTRS)

Akers, F. I.; Wightman, J. P.

1975-01-01

The rate of disappearance of atomic oxygen was measured at several pressures in a fast flow pyrex reactor system with its walls treated with (NH4)2SO4 (s), H2SO4 (l), and NH4CL (s). Atomic oxygen, P-3 was generated by dissociation of pure, low pressure oxygen in a microwave discharge. Concentrations of atomic oxygen were measured at several stations in the reactor system using chemiluminescent titration with NO2. Recombination efficiencies calculated from experimentally determined wall recombination rate constants are in good agreement with reported values for clean Pyrex and an H2SO4 coated wall. The recombination efficiency for (NH4)2SO4, results in a slightly lower value than for H2S04. A rapid exothermic reaction between atomic oxygen and the NH4Cl wall coating prevented recombination efficiency determination for this coating. The results show that the technique is highly useful for wall recombination measurements and as a means of extrapolating to the case of free stream aerosol-gas interactions.

Aerosol ionic components at Mt. Heng in central southern China: abundances, size distribution, and impacts of long-range transport.

PubMed

Gao, Xiaomei; Xue, Likun; Wang, Xinfeng; Wang, Tao; Yuan, Chao; Gao, Rui; Zhou, Yang; Nie, Wei; Zhang, Qingzhu; Wang, Wenxing

2012-09-01

Water-soluble ions in PM(2.5) were continuously measured, along with the measurements of many other species and collection of size-resolved aerosol samples, at the summit of Mt. Heng in the spring of 2009, to understand the sources of aerosols in rural central southern China. The mean concentrations of SO(4)(2-), NH(4)(+) and NO(3)(-) in PM(2.5) were 8.02, 2.94 and 1.47 μg/m(3), indicating a moderate aerosol pollution level at Mt. Heng. Water-soluble ions composed approximately 40% of the PM(2.5) mass on average. PM(2.5) was weakly acidic with about 66% of the samples being acidic. SO(4)(2-), NO(3)(-) and NH(4)(+) exhibited similar diurnal patterns with a broad afternoon maximum. SO(4)(2-) and NH(4)(+) were mainly present in the fine aerosols with a peak in the droplet mode of 0.56-1 μm, suggesting the important role of cloud processing in the formation of aerosol sulfate. NO(3)(-) was largely distributed in the coarse particles with a predominant peak in the size-bin of 3.2-5.6 μm. Long-distance transport of processed air masses, dust aerosols, and cloud/fog processes were the major factors determining the variations of fine aerosol at Mt. Heng. The results at Mt. Heng were compared with those obtained from our previous study at Mt. Tai in north China. The comparison revealed large differences in the aerosol characteristics and processes between southern and northern China. Backward trajectories indicated extensive transport of anthropogenic pollution from the coastal regions of eastern/northern China and the Pearl River Delta (PRD) to Mt. Heng in spring, highlighting the need for regionally coordinated control measures for the secondary pollutants. Copyright © 2012 Elsevier B.V. All rights reserved.

A field study to evaluate runoff quality from green roofs.

PubMed

Vijayaraghavan, K; Joshi, U M; Balasubramanian, R

2012-03-15

Green (vegetated) roofs are emerging as practical strategies to improve the environmental quality of cities. However, the impact of green roofs on the storm water quality remains a topic of concern to city planners and environmental policy makers. This study investigated whether green roofs act as a source or a sink of various metals (Na, K, Ca, Mg, Al, Fe, Cu, Cd, Pb, Zn, Mn, Cr, Ni, Li and Co), inorganic anions (NO3-, NO2-, PO4(3-), SO4(2-), Cl-, F- and Br-) and cation (NH4+). A series of green roof assemblies were constructed. Four different real rain events and several artificial rain events were considered for the study. Results showed that concentrations of most of the chemical components in runoff were highest during the beginning of rain events and subsided in the subsequent rain events. Some of the important components present in the runoff include Na, K, Ca, Mg, Li, Fe, Al, Cu, NO3-, PO4(3-) and SO4(2-). However, the concentration of these chemical components in the roof runoff strongly depends on the nature of substrates used in the green roof and the volume of rain. Based on the USEPA standards for freshwater quality, we conclude that the green roof used in this study is reasonably effective except that the runoff contains significant amounts of NO3- and PO4(3-). Copyright © 2011 Elsevier Ltd. All rights reserved.

Oxidation of SO2 by NO2 and O3 on carbon - Implications to tropospheric chemistry

NASA Technical Reports Server (NTRS)

Cofer, W. R., III; Schryer, D. R.; Rogowski, R. S.

1984-01-01

The oxidation of SO2 to sulfate in air at 65 percent relative humidity on carbon particles was investigated gravimetrically in the presence of NO2 and O3. Approximately 1 mg samples of carbon black were exposed to continuously flowing ppbv mixtures of SO2, SO2 + NO2 and SO2 + O3 for prescribed periods of time before desorption into dry N2. Wet chemical analysis of the particles followed desorption. NO2 and O3 were found to have little, if any, effect relative to air on sulfate yields at the concentrations studied.

Responses of soil buffering capacity to acid treatment in three typical subtropical forests.

PubMed

Jiang, Jun; Wang, Ying-Ping; Yu, Mengxiao; Li, Kun; Shao, Yijing; Yan, Junhua

2016-09-01

Elevated anthropogenic acid deposition can significantly affect forest ecosystem functioning by changing soil pH, nutrient balance, and chemical leaching and so on. These effects generally differ among different forests, and the dominant mechanisms for those observed responses often vary, depending on climate, soil conditions and vegetation types. Using soil monoliths (0-40cm) from pine forest (pioneer), coniferous and broadleaved mixed forest (transitional) and broadleaved forest (mature) in southern China, we conducted a leaching experiment with acid treatments at different pH levels (control: pH≈4.5; pH=3.5; pH=2.5). We found that pH3.5 treatment significantly reduced dissolved organic carbon (DOC) concentrations in leachate from the pioneer forest soil. pH2.5 treatment significantly increased concentrations of NO3(-), SO4(2-), Ca(2+), Mg(2+), Al(3+), Fe(3+) and DOC in leachate from the pioneer forest soil, and also concentrations of NO3(-), SO4(2-), Mg(2+), Al(3+), Fe(3+) and DOC in leachate from the transitional forest soil. All acid treatments had no significant effects on concentrations of these chemicals in leachate from the mature forest soil. The responses can be explained by the changes in soil pH, acid neutralizing capacity (ANC) and concentrations of Al and Fe. Our results showed that acid buffering capacity of the pioneer or transitional forest soil was lower than that of the mature forest soil. Therefore preserving mature forests in southern China is important for reducing the adverse impacts of high acid deposition on stream water quality at present and into the future. Copyright © 2016 Elsevier B.V. All rights reserved.

Civil aviation impacts on local air quality: A survey inside two international airports in central Italy

NASA Astrophysics Data System (ADS)

Vichi, Francesca; Frattoni, Massimiliano; Imperiali, Andrea; Balducci, Catia; Cecinato, Angelo; Perilli, Mattia; Romagnoli, Paola

2016-10-01

The results of air quality monitoring carried out over several years (2008-2012) in two international airports near Rome (labelled as A and B) are reported and discussed. Airport A serves regular flights, airport B operates low-cost flights and, during the period investigated, had about 17% of airport A aircraft traffic load. Diffusive sampling of gaseous species (NO2, SO2, BTX and O3) was performed at several sites inside the airports. During 2012 the investigation was improved by including PM10 and polycyclic aromatic hydrocarbons (PAHs). Higher concentrations of NO2 (+18%) and lower of SO2 (-20%) were found at airport B, compared to A, over the whole period investigated. The maximum concentrations of SO2 were measured in 2011 at both airports (13.4 μg/m3 and 10.8 μg/m3 respectively for A and B), despite the decrease of aircraft traffic load recorded. Statistical analysis of PM10 data showed that there was no significant difference between the average concentrations measured at the two airports (25.7 μg/m3 and 27.4 μg/m3 for A and B respectively) and among the sites investigated. The concentration of PAHs at airport B (4.3 ng/m3) was almost twice that of airport A (2.2 ng/m3), though the respective percentages of compounds were similar. Airport B seemed to be negatively influenced by its surroundings, in particular by vehicular traffic flows of two major roads, whereas airport A was positively influenced by the proximity to the seaside. PCA data analysis showed that airport A sites are differently impacted by the LTO flight phases according to their position, whereas at airport B it was impossible to find similar relationships.

Kinetically Determined Hygroscopicity and Efflorescence of Sucrose-Ammonium Sulfate Aerosol Droplets under Lower Relative Humidity.

PubMed

Wang, Lin-Na; Cai, Chen; Zhang, Yun-Hong

2017-09-14

Organic aerosols will likely form in semisolid, glassy, and high viscous state in the atmosphere, which show nonequilibrium kinetic characteristics at low relative humidity (RH) conditions. In this study, we applied optical tweezers to investigate the water transport in a sucrose/(NH 4 ) 2 SO 4 droplet with high organic to inorganic mole ratio (OIR). The characteristic time ratio between the droplet radius and the RH was used to describe the water mass transfer difference dependent on RH. For OIR greater than 1:1 in sucrose/(NH 4 ) 2 SO 4 droplets, the characteristic time ratio at low RH (<∼30% RH) was two orders magnitude greater than that at high RH (>∼60%). We also coupled vacuum FTIR spectrometer and a high-speed photography to study the efflorescence process in sucrose/(NH 4 ) 2 SO 4 droplets with low OIR. The crystalline fraction of (NH 4 ) 2 SO 4 was used to understand efflorescence behavior when the RH was linearly decreasing with a velocity of 1.2% RH min -1 . Because of suppression of (NH 4 ) 2 SO 4 nucleation by addition of sucrose, the efflorescence relative humidity (ERH) of (NH 4 ) 2 SO 4 decrease from the range of ∼48.2% to ∼36.1% for pure (NH 4 ) 2 SO 4 droplets to from ∼44.7% to ∼25.4%, from ∼43.2% to ∼21.2%, and from ∼41.7% to ∼21.1% for the mixed droplets with OIR of 1:4, 1:3, and 1:2, respectively. No crystallization was observed when the OIR is higher than 1:1. Suppression of (NH 4 ) 2 SO 4 crystal growth was also observed under high viscous sucrose/(NH 4 ) 2 SO 4 droplets at lower RH.

Mortality and Morbidity Due to Exposure to Ambient NO2, SO2, and O3 in Isfahan in 2013-2014.

PubMed

Abdolahnejad, Ali; Jafari, Negar; Mohammadi, Amir; Miri, Mohammad; Hajizadeh, Yaghoub

2018-01-01

The presence of air pollutants such as CO, NO 2 , SO 2 , O 3 , and PM in the ambient air mainly emitted from fossil fuels combustion has become a major health concern. The aims of this study were to estimate the attribution of NO 2 , SO 2 , and O 3 in the premature deaths and prevalence of cardiovascular and respiratory diseases in Isfahan in 2013-2014. In this study, short-term health effects (total mortality, cardiovascular and respiratory mortality, chronic obstructive pulmonary disease, and acute myocardial infarction) of exposure NO 2 , SO 2 , and O 3 on the population of Isfahan were assessed using AirQ 2.2.3 software suggested by the World Health Organization (WHO). The result showed that from nonaccident total mortality in 2013-2014 in Isfahan, the attributable proportion related to NO 2 , SO 2 , and O 3 were 1.03% (109 cases), 3.46% (365 cases), and 1.29% (136 cases), respectively. The percentage of days that people were exposed to the highest concentration of NO 2 (40-49 μg/m 3 ), SO 2 (60-69 μg/m 3 ), and O 3 (40-49 μg/m 3 ) was 34.46%, 16.85%, and 42.74% of a year, respectively. Total mortality attributed to NO 2 , SO 2 , and O 3 exposure was 0.36%, 0.79%, and 0.83%, respectively. The concentrations of NO 2 and SO 2 were upper than the WHO guidelines. The Air-Q software in spite of its limitations can provide useful information regarding the health outcome of the air pollutants. The results estimated in this study were considerable. This information can help the health authorities and policy makers to draw suitable strategies and fulfill effective emission control programs.

Association between long-term exposure to outdoor air pollution and mortality in China: a cohort study.

PubMed

Cao, Jie; Yang, Chunxue; Li, Jianxin; Chen, Renjie; Chen, Bingheng; Gu, Dongfeng; Kan, Haidong

2011-02-28

No prior cohort studies exist in China examining the association of outdoor air pollution with mortality. We studied 70,947 middle-aged men and women in the China National Hypertension Survey and its follow-up study. Baseline data were obtained in 1991 using a standard protocol. The follow-up evaluation was conducted in 1999 and 2000. Annual average air pollution exposure between 1991 and 2000, including total suspended particle (TSP), sulfur dioxide (SO(2)) and nitrogen oxides (NO(x)), were estimated by linking fixed-site monitoring data with resident zip code. We examined the association of air pollution with mortality using proportional hazards regression model. We found significant associations between air pollution levels and mortality from cardiopulmonary diseases and from lung cancer. Each 10 μg/m(3) elevation of TSP, SO(2) and NO(x) was associated with a 0.9% (95%CI: 0.3%, 1.5%), 3.2% (95%CI: 2.3%, 4.0%), and 2.3% (95%CI: 0.6%, 4.1%) increased risk of cardiovascular mortality, respectively. We found significant effects of SO(2) on mortality after adjustment for TSP. Conclusively, ambient air pollution was associated with increased cardiopulmonary and lung cancer mortality in China. These data contribute to the scientific literature on long-term effects of air pollution for high exposure settings typical in developing countries. Copyright © 2010 Elsevier B.V. All rights reserved.

Secondary inorganic aerosols formation during haze episodes at an urban site in Beijing, China

NASA Astrophysics Data System (ADS)

Zhang, Rui; Sun, Xuesong; Shi, Aijun; Huang, Yuhu; Yan, Jing; Nie, Teng; Yan, Xiao; Li, Xuan

2018-03-01

Severe PM2.5 pollution was observed frequently in Beijing. We conducted highly time-resolved measurements of inorganic ions associated with PM2.5 at an urban site in Beijing from 10 February to 19 March, 2015. The average PM2.5 mass concentrations during the six haze episodes ranged from 113.0 μg/m3 to 182.6 μg/m3, which were more than 8 times higher than those observed in clean periods. The secondary inorganic species (NH4+, SO42- and NO3-) in PM2.5 sharply increased during the haze episodes, indicating more extensive formation of SO42- and NO3-. The sulfur oxidation ratios (SOR) and the nitrogen oxidation ratios (NOR) in haze episodes were higher than those in clean periods, which indicated that secondary transformation in haze episodes was more significant than those in clean periods. No correlations between SOR and the oxidants (O3 and HONO) and the temperature were found, whereas a high correlation between SOR and relative humidity (RH) was found in haze episodes, which implied that sulfate was mainly produced by the aqueous-phase oxidation of SO2 rather than the gas-phase conversion of SO2 to sulfate. The conversion of SO2 to SO42- was observed to be sensitive to changes in RH. Furthermore, the SOR sharply increased at RH > 60% with the highest value of 0.88 at RH around 80% during complicated pollution. NO2 played an important role in the rapid sulfate formation with high RH and NH3 neutralization conditions in haze episodes in Beijing. The impact of RH was less apparent for nitrate than for sulfate. Nitrate was found to be produced mainly by photochemical and heterogeneous reactions, while heterogeneous reactions had a greater influence on NOR at nighttime. The NO3-/SO42- ratio indicated that mobile sources contributed more to the formation of PM2.5 than stationary sources. The result suggested the need for control of vehicle emissions to reduce the high levels of NOx and nitrate and the severe PM2.5 pollution in Beijing.

Impacts of inorganic anions and natural organic matter on thermally activated persulfate oxidation of BTEX in water.

PubMed

Ma, Jie; Yang, Yongqi; Jiang, Xianchenghao; Xie, Zhuoting; Li, Xiaoxuan; Chen, Changzhao; Chen, Hongkun

2018-01-01

The present study investigated the impacts of water matrix constituents (CO 3 2- , HCO 3 - , Cl - , Br - , PO 4 3- , HPO 4 2- , H 2 PO 4 - , NO 3 - , SO 4 2- and natural organic matters (NOM) on the oxidation of a mixture of benzene, toluene, ethylbenzene, and xylenes (BTEX) by thermally activated persulfate (PS). In the absence of matrix constituents, the BTEX oxidation rates decreased in the following order: xylenes > toluene ≈ ethylbenzene > benzene. HCO 3 - /CO 3 2- and NOM inhibited the BTEX oxidation and the inhibiting effects became more pronounced as the HCO 3 - /CO 3 2- /NOM concentration increased. SO 4 2- , NO 3 - , PO 4 3- and H 2 PO 4 - did not affect the BTEX oxidation while HPO 4 2- slightly inhibited the reaction. The impacts of Cl - and Br - were complex. Cl - inhibited the benzene oxidation while 100 mM and 500 mM of Cl - promoted the oxidation of m-xylene and p-xylene. Br - completely suppressed the benzene oxidation while 500 mM of Br - strongly promoted the oxidation of xylenes. Detailed explanations on the influence of each matrix constituent were discussed. In addition, various halogenated degradation byproducts were detected in the treatments containing Cl - and Br - . Overall, this study indicates that some matrix constituents such as NOM, HCO 3 - , CO 3 2- , H 2 PO 4 - , Cl - and Br - may reduce the BTEX removal efficiency of sulfate radical-based advanced oxidation process (SR-AOP) and the presence of Cl - and Br - may even lead to the formation of toxic halogenated byproducts. Copyright © 2017 Elsevier Ltd. All rights reserved.

Assessment of the availability of As and Pb in soils after in situ stabilization.

PubMed

Zhang, Wanying; Yang, Jie; Li, Zhongyuan; Zhou, Dongmei; Dang, Fei

2017-10-01

The in situ stabilization has been widely used to remediate metal-contaminated soil. However, the long-term retaining performance of heavy metals and the associated risk after in situ stabilization remains unclear and has evoked amounting concerns. Here, Pb- or As-contaminated soil was stabilized by a commercial amendment. The availability of Pb and As after in situ stabilization were estimated by ten different in vitro chemical extractions and DGT technique. After amendment application, a significant decline in extractable Pb or As was observed in treatments of Milli-Q water, 0.01 M CaCl 2 , 0.1 M NaNO 3 , 0.05 M (NH 4 ) 2 SO 4 , and 0.43 M HOAc. Potential available metal(loid)s determined by DGT also showed remarkable reduction. Meanwhile, the results of in vivo uptake assays demonstrated that Pb concentrations in shoots of ryegrass Lolium perenne L. declined to 12% of the control samples, comparable to the extraction ratio of 0.1 M NaNO 3 (15.8%) and 0.05 M (NH 4 ) 2 SO 4 (17.3%). For As-contaminated soil, 0.43 M HOAC provided a better estimation of relative phytoavailability (64.6 vs. 65.4% in ryegrass) compared to other extraction methods. We propose that 0.1 M NaNO 3 or 0.05 M (NH 4 ) 2 SO 4 for Pb and 0.43 M HOAc for As may serve as surrogate measures to estimate the lability of metal(loid)s after soil remediation of the tested contaminated soils. Further studies over a wider range of soil types and amendments are necessary to validate extraction methods.

Fast O2 Binding at Dicopper Complexes Containing Schiff-Base Dinucleating Ligands

PubMed Central

Company, Anna; Gómez, Laura; Mas-Ballesté, Rubén; Korendovych, Ivan V.; Ribas, Xavi; Poater, Albert; Parella, Teodor; Fontrodona, Xavier; Benet-Buchholz, Jordi; Solà, Miquel; Que, Lawrence; Rybak-Akimova, Elena; Costas, Miquel

2008-01-01

A new family of dicopper(I) complexes [CuI2RL](X)2, (R = H, 1X, R = tBu, 2X and R = NO2, 3X, X = CF3SO3, ClO4, SbF6 or BArF, BArF = [B{3,5-(CF3)2-C6H3}4]−), where RL is a Schiff-base ligand containing two tridentate binding sites linked by a xylyl spacer have been prepared, characterized, and their reaction with O2 studied. The complexes were designed with the aim of reproducing structural aspects of the active site of type 3 dicopper proteins; they contain two three-coordinate copper sites and a rather flexible podand ligand backbone. The solid state structures of 1ClO4, 2CF3SO3, 2ClO4 and 3BArF·CH3CN have been established by single crystal X-ray diffraction analysis. 1ClO4 adopts a polymeric structure in solution while 2CF3SO3, 2ClO4 and 3BArF·CH3CN are monomeric. The complexes have been studied in solution by means of 1H and 19F NMR spectroscopy, which put forward the presence of dynamic processes in solution. 1-3BArF and 1-3CF3SO3 in acetone react rapidly with O2 to generate metaestable [CuIII2(μ-O)2(RL)]2+ 1-3(O2) and [CuIII2(μ-O)2(CF3SO3)(RL)]+ 1-3(O2)(CF3SO3) species, respectively that have been characterized by UV-vis spectroscopy and resonance Raman analysis. Instead, reaction of 1-3BArF with O2 in CH2Cl2 results in intermolecular O2 binding. DFT methods have been used to study the chemical identities and structural parameters of the O2 adducts, and the relative stability of the CuIII2(μ-O)2 form with respect to the CuII2(μ-η2: η2-peroxo) isomer. The reaction of 1X, X = CF3SO3 and BArF with O2 in acetone has been studied by stopped-flow exhibiting an unexpected very fast reaction rate (k = 3.82(4) × 103 M−1s−1, ΔH‡ = 4.9 ± 0.5 kJ·mol−1, ΔS‡ = −148 ± 5 J·K−1·mol−1), nearly three orders of magnitude faster than in the parent [CuI2(m-XYLMeAN)]2+. Thermal decomposition of 1-3(O2) does not result in aromatic hydroxylation. The mechanism and kinetics of O2 binding to 1X (X = CF3SO3 and BArF) is discussed and compared with those associated to selected examples of reported models of O2-processing copper proteins. A synergistic role of the copper ions in O2 binding and activation is clearly established from this analysis. PMID:17500512

Polymer Vesicle Sensor for Visual and Sensitive Detection of SO2 in Water.

PubMed

Huang, Tong; Hou, Zhilin; Xu, Qingsong; Huang, Lei; Li, Chuanlong; Zhou, Yongfeng

2017-01-10

This study reports the first polymer vesicle sensor for the visual detection of SO 2 and its derivatives in water. A strong binding ability between tertiary alkanolamines and SO 2 has been used as the driving force for the detection by the graft of tertiary amine alcohol (TAA) groups onto an amphiphilic hyperbranched multiarm polymer, which can self-assemble into vesicles with enriched TAA groups on the surface. The polymer vesicles will undergo proton exchange with cresol red (CR) to produce CR-immobilized vesicles (CR@vesicles). Subsequently, through competitive binding with the TAA groups between CR and SO 2 or HSO 3 - , the CR@vesicles (purple) can quickly change into SO 2 @vesicles (colorless) with the release of protonated CR (yellow). Such a fast purple to yellow transition in the solution allows the visual detection of SO 2 or its derivatives in water by the naked eye. A visual test paper for SO 2 gas has also been demonstrated by the adsorption of CR@vesicles onto paper. Meanwhile, the detection limit of CR@vesicles for HSO 3 - is approximately 25 nM, which is improved by approximately 30 times when compared with that of small molecule-based sensors with a similar structure (0.83 μM). Such an enhanced detection sensitivity should be related to the enrichment of TAA groups as well as the CR in CR@vesicles. In addition, the CR@vesicle sensors also show selectivity and specificity for the detection of SO 2 or HSO 3 - among anions such as F - , Br - , Cl - , SO 4 2- , NO 2 - , C 2 O 4 2- , S 2 O 3 2- , SCN - , AcO - , SO 3 2- , S 2- , and HCO 3 - .

Comparative effects of selenite and selenate on nitrate assimilation in barley seedlings

NASA Technical Reports Server (NTRS)

Aslam, M.; Harbit, K. B.; Huffaker, R. C.

1990-01-01

The effect of SeO3= and SeO4= on NO3- assimilation in 8-d-old barley (Hordeum vulgare L.) seedlings was studied over a 24-h period. Selenite at 0.1 mol m-3 in the uptake solutions severely inhibited the induction of NO3- uptake and active nitrate reductases. Selenate, at 1.0 mol m-3 in the nutrient solution, had little effect on induction of activities of these systems until after 12 h; however, when the seedlings were pretreated with 1.0 mol m-3 SeO4= for 24 h, subsequent NO3- uptake from SeO4(=) -free solutions was inhibited about 60%. Sulphate partially alleviated the inhibitory effect of SeO3= when supplied together in the ambient solutions, but had no effect in seedlings pretreated with SeO3=. By contrast, SO4= partially alleviated the inhibitory effect of SeO4= even in seedlings pretreated with SeO4=. Since uptake of NO3- by intact seedlings was also inhibited by SO3=, the percentage of the absorbed NO3- that was reduced was not affected. By contrast, SeO4=, which affected NO3- uptake much less, inhibited the percentage reduced of that absorbed. However, when supplied to detached leaves, both SeO3= and SeO4= inhibited the in vivo reduction of NO3- as well as induction of nitrate reductase and nitrite reductase activities. Selenite was more inhibitory than SeO4= ; approximately a five to 10 times higher concentration of SeO4= than SeO3= was required to achieve similar inhibition. In detached leaves, the inhibitory effect of both SeO3= and SeO4= on in vivo NO3- reduction as well as on the induction of nitrate reductase activity was partially alleviated by SO4=. The inhibitory effects of Se salts on the induction of the nitrite reductase were, however, completely alleviated by SO4=. The results show that in barley seedlings SeO3= is more toxic than SeO4=. The reduction of SeO4= to SeO3= may be a rate limiting step in causing Se toxicity.

Malfunction Investigation of the XM935 Point Detonating Fuze

DTIC Science & Technology

1977-04-01

1 PSK* UNCHANGED FUMLY AR! 2 PSM UNCHANGED FULLY ARMED 3 OK PS4 UNCHANGD 4 CK P24 UNC DNGED 5 PSK (more than S.Q. Det Edge Visible FuLLY AP1M other...Continued) F= NO. DRC NO. 1 2 3 4 5 6 7 8 9 10 3 PSK UNCH UNCH UNCE SEE SQ UNCH UNCH UNCH UNCH UN1H 4 PS4 UNCH SKH E SQ UNCH tNCH UNCH UNCH U2 L!CH...EDGE 5 PS UNCH tCH SE SQ UNCH MMH UNCH UNCH UWCH WECH 6 P4M UNCH UNCH Q SEE SQ EDGE 7 PSK UNCH UNCH SEE SO WXC EDGE a P UNCP L4 UNCH SC E SQ 9 PS4 UNCX

Influence of periodically changing oxidizing and reducing environment on sulfur capture under PFBC conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yrjas, P.; Hupa, M.

1997-12-31

In the literature it has been reported that sulfur capture with limestone (CaCO{sub 3}) under atmospheric fluidized bed combustion conditions reaches a maximum at about 850 C. Previously, the maximum has been attributed to the sintering of the sorbent particles which decreases the reactive surface area. Lately, also another explanation has been reported. In this case the sulfur capture decrease at higher temperatures was concluded to be due to fluctuating oxidizing/reducing conditions in the atmospheric combustor. In this paper the influence of alternating oxidizing/reducing conditions on SO{sub 2} capture at atmospheric and elevated pressure (15 bar) is reported. In themore » pressurized case, the CO{sub 2} partial pressure was kept high enough to prevent CaCO{sub 3} from calcining and therefore the CaSO{sub 4} would not form CaO but CaCO{sub 3} from calcining and therefore the CaSO{sub 4} would not form CaO but CaCO{sub 3} under reducing conditions. The experiments were done with a pressurized TGA by periodically changing the gas environment between oxidizing (O{sub 2}, SO{sub 2}, CO{sub 2} and N{sub 2}) and slightly reducing (CO, SO{sub 2}, CO{sub 2} and N{sub 2}) gas mixtures at different temperatures. The results showed that under normal pressure and slightly reducing conditions CaO formation from CaSO{sub 4} increased with temperature as expected. However, no significant amounts of CaCO{sub 3} were formed from CaSO{sub 4} at elevated pressure. It was also concluded that since the formation of CaO from CaSO{sub 4} was relatively slow it could not explain the sharp sulfur capture maximum at about 850 C. Therefore, it was assumed that the strongly reducing zones, where CaS thermodynamically is the stable compound, may play a more important role than the slightly reducing zones, concerning the sulfur capture in fluidized bed combustors.« less

Trace element and major ion composition of wet and dry depositon in Ankara, Turkey

NASA Astrophysics Data System (ADS)

Kaya, Güven; Tuncel, Gürdal

Daily, wet-only precipitation samples collected over a two year period were analyzed for SO 42-, NO 3-, Cl -, NH 4+, H +, Ca, Mg, K, Na, Al, Cu, Cd, Cr, Zn, V and Ni. Weekly dry-deposition samples collected on petri-dishes over the same period were analyzed only for major ions. Concentrations of ions and elements in Ankara precipitation are comparable with concentrations reported in literature for other urban areas. However, the wet deposition fluxes are the lowest among literature values, owing to small annual precipitation in the region. Although, annual average pH in precipitation is 4.7, episodic rain events with fairly low pH's were observed. Approximately half of the acidity in Ankara precipitation is neutralized in the winter season, while the acidity is completely neutralized by airborne soil particles that are rich in CaCO 3 in the summer precipitation. The SO 42- and NO 3- contributes approximately equally on the free acidity in winter. Main forms of SO 42- and NO 3- in precipitation are CaSO 4 and Ca(NO 3) 2, respectively. Crustal elements and ions have higher concentrations during summer season, while anthropogenic ions and elements did not show well-defined seasonal cycles. The lack of industrial activity in Ankara has profound influence on the temporal behavior of elements and ions.

Simultaneous removal of selected oxidized contaminants in groundwater using a continuously stirred hydrogen-based membrane biofilm reactor.

PubMed

Xia, Siqing; Liang, Jun; Xu, Xiaoyin; Shen, Shuang

2013-01-01

A laboratory trial was conducted for evaluating the capability of a continuously stirred hydrogen-based membrane biofilm reactor to simultaneously reduce nitrate (NO(3-)-N), sulfate (SO4(2-)), bromate (BrO3-), hexavalent chromium (Cr(VI)) and parachloronitrobenzene (p-CNB). The reactor contained two bundles of hollow fiber membranes functioning as an autotrophic biofilm carrier and hydrogen pipe as well. On the condition that hydrogen was supplied as electron donor and diffused into water through membrane pores, autohydrogenotrophic bacteria were capable of reducing contaminants to forms with lower toxicity. Reduction occurred within 1 day and removal fluxes for NO(3-)-N, SO4(2-), BrO3-, Cr(VI), and p-CNB reached 0.641, 2.396, 0.008, 0.016 and 0.031 g/(day x m2), respectively after 112 days of continuous operation. Except for the fact that sulfate was 37% removed under high surface loading, the other four contaminants were reduced by over 95%. The removal flux comparison between phases varying in surface loading and H2 pressure showed that decreasing surface loading or increasing H2 pressure would promote removal flux. Competition for electrons occurred among the five contaminants. Electron-equivalent flux analysis showed that the amount of utilized hydrogen was mainly controlled by NO(3-)-N and SO4(2-) reduction, which accounted for over 99% of the electron flux altogether. It also indicated the electron acceptor order, showing that nitrate was the most prior electron acceptor while suIfate was the second of the five contaminants.

Three-week combination treatment with ACTH + magnesium sulfate versus ACTH monotherapy for infantile spasms: a 24-week, randomized, open-label, follow-up study in China.

PubMed

Zou, Li-Ping; Wang, Xu; Dong, Chang-Hong; Chen, Chun-Hong; Zhao, Wei; Zhao, Ruo-Yan

2010-04-01

Infantile spasms (IS) is an age-specific and severe epileptic encephalopathy that occurs in infancy and early childhood and is usually refractory to conventional antiepileptic drugs. Adrenocorticotropic hormone (ACTH) has been the treatment of choice for IS, but ACTH use has been associated with infection and hypertension. Magnesium ion is an N-methyl-D-aspartic acid (NMDA)-noncompetitive antagonist that might inhibit NMDA activity and has antiepileptic and neuroprotective effects. This study compared the efficacy and tolerability of ACTH + magnesium sulfate (MgSO(4)) versus ACTH monotherapy for the treatment of IS. This 24-week, randomized, open-label follow-up study enrolled male and female infants with IS. Patients were randomly assigned to receive ACTH 25 U/d + MgSO(4) 0.25 g/kg/d, or ACTH 25 U/d only (control), intravenously for 3 weeks. Efficacy was assessed over a period of 24 weeks based on seizure frequency, EEG, and Gesell testing of psychomotor skills (subscales: language, motor, adaptive, and personal-social skills; measured using a developmental quotient [DQ] ). Tolerability was assessed by monitoring for adverse events using laboratory analysis and clinical evaluation. Thirty-eight infants were enrolled (23 male, 15 female; median age, 9.2 months; 19 patients per group). At 12 weeks, 14 patients (73.7%) who received ACTH + MgSO(4) and 9 patients (47.4%) in the control group were seizure free. At 24 weeks, seizure-free rates were 12 (63.2%) in the ACTH + MgSO(4) group and 10 (52.6%) in the control group. On EEG, 9 patients (47.4%) in the ACTH + MgSO(4) group achieved complete recovery (normalized EEG), 5 (26.3 %) attained partial improvement (multifocal spike wave), and 5 (26.3%) had no improvement (hypsarrhythmia or modified hypsarrhythmia). At 4 weeks, in the control group, 5 patients (26.3 %) achieved complete recovery, 6 (31.6%) achieved partial improvement, and 8 (42.1%) had no improvement. Of the 12 patients who were seizure free at 24 weeks in the ACTH + MgSO(4) group, 11 (91.7%) had complete recovery (normalized EEG); this rate was 7 of 10 (70.0%) in the control group. In the ACTH + MgSO(4) group, the change from baseline to 24 weeks in mean (SD) personal-social DQ was significant (from 48.6 [6.4] to 65.2 [7.1], respectively; P < 0.05). In the control group, the difference before and after treatment was nonsignificant (47.7 [6.0] vs 49.9 [4.4]). None of the other Gesell test findings were significant versus baseline. The most common AEs included upper respiratory tract infection and pyrexia (both, 3 [15.8%] per group); diarrhea (2 [10.5%] per group); and hypertension, insomnia, and irritability (all, 0 in the ACTH + MgSO(4) group and 2 [10.5%] in the control group). None of the between-group differences in the prevalences of AEs were significant between the 2 groups. In this study in infants with IS, the proportions of patients who were seizure free from 4 to 24 weeks were significantly greater in the ACTH + MgSO(4) group compared with the ACTH monotherapy group. Personal-social neurodevelopment was significantly improved from baseline in the group that received combination treatment. Both treatments were generally well tolerated. International Standard Randomized Controlled Trial no. ISRCTN 78654111.

Growth of radish and marigold following repeated exposure to nitrogen dioxide, sulfur dioxide, and ozone

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reinert, R.A.; Sanders, J.S.

Radish and marigold plants were exposed to 0.3 ppm of nitrogen dioxide (NO/sub 2/), sulfur dioxide (SO/sub 2/), and/or ozone (O/sub 3/) nine times during a 3-wk period. No interactions among NO/sub 2/, SO/sub 2/, and O/sub 3/ were detected in measurement of radish foliage and root dry weight. Treatments containing O/sub 3/ reduced radish foliage and root (hypocotyl) dry weight 356 and 531 mg/plant, respectively. Interactions among NO/sub 2/, SO/sub 2/, and O/sub 3/ occurred in shoots and roots of marigold. SO/sub 2/ alone reduced marigold shoot and root dry weight, but this effect was reversed in the presencemore » of O/sub 3/. The suppressive effect of SO/sub 2/ on root weight was also reversed by NO/sub 3/. Treatments containing SO/sub 2/ reduced dry flower weight 0.17 g/plant, but effects of the pollutant interactions observed in shoots and roots were not present.« less

Effect of subalpine canopy removal on snowpack, soil solution, and nutrient export, Fraser Experimental Forest, CO

USGS Publications Warehouse

Stottlemyer, R.; Troendle, C.A.

1999-01-01

Research on the effects of vegetation manipulation on snowpack, soil water, and streamwater chemistry and flux has been underway at the Fraser Experimental Forest (FEF), CO, since 1982. Greater than 95% of FEF snowmelt passes through watersheds as subsurface flow where soil processes significantly alter meltwater chemistry. To better understand the mechanisms accounting for annual variation in watershed streamwater ion concentration and flux with snowmelt, we studied subsurface water flow, its ion concentration, and flux in conterminous forested and clear cut plots. Repetitive patterns in subsurface flow and chemistry were apparent. Control plot subsurface flow chemistry had the highest ion concentrations in late winter and fall. When shallow subsurface flow occurred, its Ca2+, SO42-, and HCO3- concentrations were lower and K+ higher than deep flow. The percentage of Ca2+, NO3-, SO42-, and HCO3- flux in shallow depths was less and K+ slightly greater than the percentage of total flow. Canopy removal increased precipitation reaching the forest floor by about 40%, increased peak snowpack water equivalent (SWE) > 35%, increased the average snowpack Ca2+, NO3-, and NH4+ content, reduced the snowpack K+ content, and increased the runoff four-fold. Clear cutting doubled the percentage of subsurface flow at shallow depths, and increased K+ concentration in shallow subsurface flow and NO3- concentrations in both shallow and deep flow. The percentage change in total Ca2+, SO42-, and HCO3- flux in shallow depths was less than the change in water flux, while that of K+ and NO3- flux was greater. Relative to the control, in the clear cut the percentage of total Ca2+ flux at shallow depths increased from 5 to 12%, SO42- 5.4 to 12%, HCO3- from 5.6 to 8.7%, K+ from 6 to 35%, and NO3- from 2.7 to 17%. The increases in Ca2+ and SO42- flux were proportional to the increase in water flux, the flux of HCO3- increased proportionally less than water flux, and NO3- and K+ were proportionally greater than water flux. Increased subsurface flow accounted for most of the increase in non-limiting nutrient loss. For limiting nutrients, loss of plant uptake and increased shallow subsurface flow accounted for the greater loss. Seasonal ion concentration patterns in streamwater and subsurface flow were similar.Research on the effects of vegetation manipulation on snowpack, soil water, and streamwater chemistry and flux has been underway at the Fraser Experimental Forest (FEF), CO, since 1982. Greater than 95% of FEF snowmelt passes through watersheds as subsurface flow where soil processes significantly alter meltwater chemistry. To better understand the mechanisms accounting for annual variation in watershed streamwater ion concentration and flux with snowmelt, we studied subsurface water flow, its ion concentration, and flux in conterminous forested and clear cut plots. Repetitive patterns in subsurface flow and chemistry were apparent. Control plot subsurface flow chemistry had the highest ion concentrations in late winter and fall. When shallow subsurface flow occurred, its Ca2+, SO42-, and HCO3- concentrations were lower and K+ higher than deep flow. The percentage of Ca2+, NO3-, SO42-, and HCO3- flux in shallow depths was less and K+ slightly greater than the percentage of total flow. Canopy removal increased precipitation reaching the forest floor by about 40%, increased peak snowpack water equivalent (SWE) > 35%, increased the average snowpack Ca2+, NO3-, and NH4+ content, reduced the snowpack K+ content, and increased the runoff four-fold. Clear cutting doubled the percentage of subsurface flow at shallow depths, and increased K+ concentration in shallow subsurface flow and NO3- concentrations in both shallow and deep flow. The percentage change in total Ca2+, SO42-, and HCO3- flux in shallow depths was less than the change in water flux, while that of K+ and NO3- flux was greater. Relative to the control, in the clear cut the percentage of total Ca

Purification and some properties of rose (Fructus cynosbati) hips invertase.

PubMed

Sacan, Ozlem; Yanardag, Refiye

2012-04-01

Invertase was purified from rose (Fructus cynosbati) hips by ammonium sulfate fractionation and hydroxyapatite column chromatography. The enzyme was obtained with a yield of 4.25% and about 10.48-fold purification and had a specific activity of 8.59 U/mg protein. The molecular mass of invertase was estimated to be 66.51 kDa by PAGE and 34 kDa by SDS-PAGE, indicating that the native enzyme was a homodimer. The enzyme was a glycoprotein and contained 5.86% carbohydrate. The K(m) for sucrose was 14.55 mM and the optimum pH and temperature of the enzyme were 4.5 and 40 degrees C, respectively. Sucrose was the most preferred substrate of the enzyme. The enzyme also hydrolyzed D(+) raffinose, D(+) trehalose and inulin (activity 39.88, 8.12 and 4.94%, respectively of that of sucrose), while D(+) lactose, cellobiose and D(+) maltose showed no effect on the enzyme. The substrate specificity was consistent with that for a beta-fructofuranoside, which is the most popular type in the higher plants. The enzyme was completely inhibited by HgCl2, MnCl2, MnSO4, FeCl3, Pb(NO3)2, ammonium heptamolybdate, iodoacetamide and pyridoxine hydrochloride. It was also inhibited by Ba(NO3)2 (86.32%), NH4Cl (84.91%), MgCl2 (74.45%), urea (71.63%), I2 (69.64%), LiCl (64.99%), BaCl2 (50.30%), Mg(NO3)2 (49.90%), CrCl3 (31.90%) and CuSO4 (21.45%) and but was activated by Tris (73.99%) and methionine (12.47%).

Antibacterial and anticancer activity of ε-poly-L-lysine (ε-PL) produced by a marine Bacillus subtilis sp.

PubMed

El-Sersy, Nermeen A; Abdelwahab, Abeer E; Abouelkhiir, Samia S; Abou-Zeid, Dunja-Manal; Sabry, Soraya A

2012-10-01

A marine Bacillus subtilis SDNS was isolated from sea water in Alexandria and identified using 16S rDNA sequence analysis. The bacterium produced a compound active against a number of gram negativeve bacteria. Moreover, the anticancer activity of this bacterium was tested against three different human cell lines (Hela S3, HepG2 and CaCo). The highest inhibition activity was recorded against Hela S3 cell line (77.2%), while almost no activity was recorded towards CaCo cell line. HPLC and TLC analyses supported evidence that Bacillus subtilis SDNS product is ε-poly-L-lysine. To achieve maximum production, Plackett-Burman experimental design was applied. A 1.5 fold increase was observed when Bacillus subtilis SDNS was grown in optimized medium composed of g/l: (NH(4))(2) SO(4), 15; K(2)HPO(4), 0.3; KH(2)PO(4), 2; MgSO(4) · 7 H(2)O, 1; ZnSO(4) · 7 H(2)O, 0; FeSO(4) · 7 H(2)O, 0.03; glucose, 25; yeast extract, 1, pH 6.8. Under optimized culture condition, a product value of 76.3 mg/l could be obtained. According to available literature, this is the first announcement for the production of ε-poly-L-lysine (ε-PL) by a member of genus Bacillus. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effect of magnesium sulfate nebulization on the incidence of postoperative sore throat.

PubMed

Yadav, Monu; Chalumuru, Nitish; Gopinath, Ramachandran

2016-01-01

Postoperative sore throat (POST) is a well-recognized complication after general anesthesia (GA). Numerous nonpharmacological and pharmacological measures have been used for attenuating POST with variable success. The present study was conducted to compare the efficiency of preoperative nebulization of normal saline and magnesium sulfate in reducing the incidence of POST following GA. Following institutional ethical committee approval and written informed consent, a prospective randomized double-blinded study was conducted in 100 cases divided into two equal groups. Patients included in the study were of either gender belonging to American Society of Anesthesiologist (ASA) status 1 or 2 undergoing elective surgery of approximately 2 h or more duration requiring tracheal intubation. Patients in Group A are nebulized with 3 ml of normal saline and the patients in Group B are nebulized with 3 ml of 225 mg isotonic nebulized magnesium sulfate for 15 min, 5 min before induction of anesthesia. The incidence of POST at rest and on swallowing and any undue complaints at 0, 2, 4, and 24 h in the postoperative period are evaluated. There is no significant difference in POST at rest during 0(th), 2(nd) and 4(th) h between normal saline and MgSO4. Significant difference is seen at 24(th) h, where MgSO4 lessens POST. There is no significant difference in POST on swallowing during 0(th) and 2(nd) h between normal saline and MgSO4. Significant difference is seen at 4(th) h, where MgSO4 has been shown to lessen POST. MgSO4 significantly reduces the incidence of POST compared to normal saline.

2,3-Dihydroxybenzoic acid amides of tetraazaalkanes and tetaaza cycloalkanes

DOEpatents

Weitl, F.L.; Raymond, K.N.

1980-01-01

This disclosure is directed to a compound of the formula given in the patent wherein X is hydrogen or a conventional electron-withdrawing group, particularly --SO[sub 3]H or a salt thereof; n is 2, 3, or 4; m is 2, 3, or 4; and p is 2 or 3. The present compounds are useful as specific sequestering agents for actinide (IV) ions. Also described is a method for the 2,3-dihydroxybenzamidation of azaalkanes. No Drawings

The air pollution caused by the burning of fireworks during the lantern festival in Beijing

NASA Astrophysics Data System (ADS)

Wang, Ying; Zhuang, Guoshun; Xu, Chang; An, Zhisheng

The effects of the burning of fireworks on air quality in Beijing was firstly assessed from the ambient concentrations of various air pollutants (SO 2, NO 2, PM 2.5, PM 10 and chemical components in the particles) during the lantern festival in 2006. Eighteen ions, 20 elements, and black carbon were measured in PM 2.5 and PM 10, and the levels of organic carbon could be well estimated from the concentrations of dicarboxylic acids. Primary components of Ba, K, Sr, Cl -, Pb, Mg and secondary components of C 5H 6O 42-, C 3H 2O 42-, C 2O 42-, C 4H 4O 42-, SO 42-, NO 3- were over five times higher in the lantern days than in the normal days. The firework particles were acidic and of inorganic matter mostly with less amounts of secondary components. Primary aerosols from the burning of fireworks were mainly in the fine mode, while secondary formation of acidic anions mainly took place on the coarse particles. Nitrate was mainly formed through homogeneous gas-phase reactions of NO 2, while sulfate was largely from heterogeneous catalytic transformations of SO 2. Fe could catalyze the formation of nitrate through the reaction of α-Fe 2O 3 with HNO 3, while in the formation of sulfate, Fe is not only the catalyst, but also the oxidant. A simple method using the concentration of potassium and a modified method using the ratio of Mg/Al have been developed to quantify the source contribution of fireworks. It was found that over 90% of the total mineral aerosol and 98% of Pb, 43% of total carbon, 28% of Zn, 8% of NO 3-, and 3% of SO 42- in PM 2.5 were from the emissions of fireworks on the lantern night.

Effect of industrial dust on precipitation chemistry in the Czech Republic (Central Europe) from 1850 to 2013.

PubMed

Kopáček, Jiří; Hejzlar, Josef; Krám, Pavel; Oulehle, Filip; Posch, Maximilian

2016-10-15

Using statistical relationships between the composition of precipitation at eight long-term monitoring stations and emission rates of sulphur (S) and nitrogen (N) compounds, as well as industrial dust in the Czech Republic and Slovakia (Central Europe), we modelled historic pH and concentrations of sulphate (SO4(2-)), nitrate (NO3(-)), ammonium (NH4(+)), chloride (Cl(-)), base cations (BC), and bicarbonate (HCO3(-)) in bulk precipitation from 1850 to 2013. Our model suggests that concentrations of SO4(2-), NO3(-), and HCO3(-) were similar (11-16 μeq l(-1)) in 1850. Cations were dominated by NH4(+) and BC (24-27 μeq l(-1)) and precipitation pH was >5.6. The carbonate buffering system was depleted around 1920 and precipitation further acidified at an exponential rate until the 1980s, when concentrations of SO4(2-), NO3(-), Cl(-), NH4(+) and BC reached maxima of 126, 55, 16, 76, and 57 μeq l(-1), respectively, and pH decreased to 4.2. Dust emissions from industrial sources were an important source of BC. Without their contribution, pH would have decreased to 4.0 in the 1980s, and the carbonate buffering system would have been depleted already in the 1870s. Since the late 1980s, concentrations of strong acid anions and BC have decreased by 46-81% (i.e. more than in Europe on average) due to a 53-93% reduction in regional emissions of S and N compounds and dust from industrial and agricultural sources. The present composition of precipitation is similar to the late 19th century, except for NO3(-) concentrations, which are similar to those during 1926-1950. Precipitation pH now exceeds 5.0, the carbonate buffering system has been re-established, and HCO3(-) has again become (after almost a century) a significant component of precipitation chemistry. Copyright © 2016 Elsevier Ltd. All rights reserved.

Characterization of ambient aerosol at a remote site and twin cities of Pakistan

NASA Astrophysics Data System (ADS)

Ghauri, B.; Lodhi, A.

The pollution controls have significantly decreased pollutant concentrations in the industrialized nations in the west while the concentrations are expected to grow in developing countries. In this study the concentrations of major ions i.e SO4 2 -, NO3 -, NO2 -, Cl- , NH4 + and trace metals i.e. Al, V, Cr, Mn, Cu, As, Se, Cd, Sb, Ba, Ti and Pb were determined in aerosols at a remote site of Northern Pakistan in July 1996. Later in May 1998, a comparative study of aerosols in two size fractions (bulk &PM10) at 14 sites enabled to understand the anomalous distribution of several constituents present in the ambient air of the twin cities, Islamabad / Rawalpindi 90 km from South East of earlier site. The suspended particulate matter concentrations (bulk and PM10) were 475 ug/m3, 175 ug/m3 respectively. For urban areas Pb, Cd, Zn and Ni are obviously contributed by steel and other allied industries besides vehicle's contribution of lead and cadmium. In Northern area concentrations of Al, K, Ca, and Fe exceeded 1000 ng/m3. The SO2 concentrations varied from 0.03 to 1.2 ppb. Mean SO4 2- and NO3 - concentrations were 5.2 ug/m3 and 3.6 ug/m3 respectively. Concentrations of Se, Ti, Pb, Cd, Sb, Zn and As in all aerosol samples were highly enriched relative to average crustal abundances indicating significant anthropogenic contributions. As the dominant flow pattern from the Arabian Sea through India (monsoon air pattern) this may transport pollution derived aerosol and moisture from distant sources in China or India. Key word index: Aerosol, trace metals , enrichment, anions, air pollution, Islamabad/Rawalpindi, remote site.

The ternary system K2SO4MgSO4CaSO4

USGS Publications Warehouse

Rowe, J.J.; Morey, G.W.; Silber, C.C.

1967-01-01

Melting and subsolidus relations in the system K2SO4MgSO4CaSO4 were studied using heating-cooling curves, differential thermal analysis, optics, X-ray diffraction at room and high temperatures and by quenching techniques. Previous investigators were unable to study the binary MgSO4CaSO4 system and the adjacent area in the ternary system because of the decomposition of MgSO4 and CaSO4 at high temperatures. This problem was partly overcome by a novel sealed-tube quenching method, by hydrothermal synthesis, and by long-time heating in the solidus. As a result of this study, we found: (1) a new compound, CaSO4??3MgSO4 (m.p. 1201??C) with a field extending into the ternary system; (2) a high temperature form of MgSO4 with a sluggishly reversible inversion. An X-ray diffraction pattern for this polymorphic form is given; (3) the inversion of ??-CaSO4 (anhydrite) to ??-CaSO4 at 1195??C, in agreement with grahmann; (1) (4) the melting point of MgSO4 is 1136??C and that of CaSO4 is 1462??C (using sealed tube methods to prevent decomposition of the sulphates); (5) calcium langbeinite (K2SO4??2CaSO4) is the only compound in the K2SO4CaSO4 binary system. This resolved discrepancies in the results of previous investigators; (6) a continuous solid solution series between congruently melting K2SOP4??2MgSO4 (langbeinite) and incongruently melting K2SO4??2CaSO4 (calcium langbeinite); (7) the liquidus in the ternary system consists of primary phase fields of K2SO4, MgSO4, CaSO4, langbeinite-calcium langbeinite solid solution, and CaSO4??3MgSO4. The CaSO4 field extends over a large portion of the system. Previously reported fields for the compounds (K2SO4??MgSO4??nCaSO4), K2SO4??3CaSO4 and K2SO4??CaSO4 were not found; (8) a minimum in the ternary system at: 740??C, 25% MgSO4, 6% CaSO4, 69% K2SO4; and ternary eutectics at 882??C, 49% MgSO4, 19% CaSO4, 32% K2SO4; and 880??, 67??5% MgSO4, 5% CaSO4, 27??5% K2SO4. ?? 1967.

Flue gas adsorption on periodic mesoporous phenylene-silica: a DFT approach.

PubMed

Lourenço, Mirtha A O; Ferreira, Paula; Gomes, José R B

2018-06-20

Periodic mesoporous organosilicas (PMOs) were suggested as potential adsorbents for CO2/CH4 separation because of their large affinities towards CO2 and low interaction with CH4. Herewith, we present a comprehensive computational study on the binding properties of flue gas species with the pore walls of periodic mesoporous phenylene-silica (Ph-PMO) for understanding the possible impact of other gaseous species in the CO2/CH4 separation. The calculations considered three exchange-correlation functionals (PBE, PBE-D2 and M06-2X) based on the density functional theory and the walls of the periodic mesoporous phenylene-silica were modelled within the cluster model approach. The components of the flue gas considered were the diatomic CO, H2, N2, O2 and NO molecules, the triatomic CO2, H2O, H2S and SO2 species, the tetratomic SO3 and NH3 gases and the pentatomic CH4 molecule. The calculated data demonstrate that the presence of H2O, SO2, NH3, H2S and SO3 is a significant threat to CO2 capture by Ph-PMO and suggest that the Ph-PMO material would present high selectivity for CO2 over CH4, CO, H2 or N2 adsorption. The adsorption behaviour of flue gas components in Ph-PMO can be directly related to the experimental proton affinities, basicities or even the polarizabilities of the gaseous molecules.

Direct observation of nitrate and sulfate formations from mineral dust and sea-salts using low- Z particle electron probe X-ray microanalysis

NASA Astrophysics Data System (ADS)

Hwang, HeeJin; Ro, Chul-Un

In the present work, it is demonstrated that a single particle analytical technique, named low- Z particle electron probe X-ray microanalysis, is a practically useful tool for the study of heterogeneous reactions of mineral dust and sea-salts when this analytical technique was applied to a sample collected during an Asian Dust storm event. The technique does not require a special treatment of sample to identify particles reacted in the air. Also, quantitative chemical speciation of reacted particles can provide concrete information on what chemical reaction, if any, occurred for individual particles. Among overall 178 analyzed particles, the number of reacted particles is 81 and heterogeneous chemical reactions mostly occurred on CaCO 3 mineral dust (54 particles) and sea-salts (26 particles). Several observations made for the Asian Dust sample in the present work are: (1) CaCO 3 species almost completely reacted to produce mostly Ca(NO 3) 2 species, and CaSO 4 to a much lesser extent. (2) When reacted particles contain CaSO 4, almost all of them are internally mixed with nitrate. (3) Reacted CaCO 3 particles seem to contain moisture when they were collected. (4) Some reacted CaCO 3 particles have unreacted mineral species, such as aluminosilicates, iron oxide, SiO 2, etc., in the core region. (5) All sea-salt particles are observed to have reacted in the air. Some of them were recrystallized in the air before being collected and they are observed as crystalline NaNO 3 particles. (6) Many sea-salts were collected as water drops, and some of them were fractionally recrystallized on Ag collecting substrate. When sea-salts were not recrystallized on the substrate, they are found as particles internally mixed with NaNO 3 and Mg(NO 3) 2, and in some cases SO 4 and Cl species as additional anions.

AN EXPERIMENTAL STUDY ON ARTIFICIAL CONDENSATION NUCLEI,

DTIC Science & Technology

NH4Cl, CaCl2, P205, NH4NO3, (NH4)2SO4, etc.) and suspensoids such as camphor , silicon minerals, kaolin, lamp black, and calcium lime (CaO). The...findings reveal that the above mentioned soluble nuclei and camphor powder are active artificial hygroscopic condensation nuclei and that lamp black

Methylsulfonyl polychlorinated biphenyls in fish from an electronic waste-recycling site in South China: levels, congener profiles, and chiral signatures.

PubMed

Zhang, Ying; Wu, Jiang-Ping; Luo, Xiao-Jun; She, Ya-Zhe; Mo, Ling; Mai, Bi-Xian

2012-11-01

Great concerns have been raised about the fate and effects of polychlorinated biphenyls (PCBs) and other organic contaminants contained in electronic waste (e-waste) exported from industrialized countries at midlatitudes to subtropical and tropical regions. Information on the metabolites of these chemicals, for example, methylsulfonyl-PCBs (MeSO(2)-PCBs) in wildlife from the later regions is scarce. In the present study, 17 MeSO(2)-PCBs, including five chiral congeners, were detected in the muscle, liver, and brain tissues of two benthic fish species--northern snakehead and mud carp--from a small pond near an electronic waste recycling site in South China. The mean concentrations of the sum of the MeSO(2)-PCBs ranged from 80 to 340 ng/g lipid weight in the tissues, with relative higher levels in the liver than the muscle and brain tissues. These levels were one order of magnitude greater than the highest levels of MeSO(2)-PCBs previously reported in fish. The 3'-MeSO(2)-CB 87, 3'- and 4'-MeSO(2)-CB 101, 4-MeSO(2)-CB 110, and 4-MeSO(2)-CB 149 were dominant, collectively comprising more than 55% of the total MeSO(2)-PCBs. Except for 4-MeSO(2)-CB149, all of the investigated chiral MeSO(2)-PCBs displayed a clear, congener-specific enantiomeric enrichment in the tissues. No tissue-specific enantioselective retention of the enantiomers was observed in the investigated fish. This is the first report on chiral signatures of MeSO(2)-PCBs in fish tissues. Copyright © 2012 SETAC.

Indoor/outdoor of PM10 relationships and its water-soluble ions composition in selected primary schools in Malaysia

NASA Astrophysics Data System (ADS)

Mohamad, Noorlin; Latif, Mohd Talib

2013-11-01

Measurements of PM10 and water-soluble ions were carried out on indoor and outdoor PM10 (particles > 10 μm in aerodynamic diameter) aerosols sampled at selected primary schools of Kuala Lumpur (S1) and Putrajaya (S2), respectively. Samples were collected using a low volume sampler on Teflon filters. The water-soluble ions chloride (Cl-), nitrate (NO3-), sulfate (SO42-), calcium (Ca2+), magnesium (Mg2+), sodium (Na+), potassium (K+) and ammonium (NH4+) was analyzed using ion chromatography. The results showed that the indoor PM10 mass concentrations in S1 and S2 were 96.6 and 69.5 μg/m3, while the outdoor PM10 mass concentrations were 80.1 and 85.2 μg/m3, respectively. This indicated that NO3- were the most dominant ions, followed by SO42-, Ca2+, K+ and Na+, while Cl-, Mg2+ and Na+ were present at low concentrations. Pearson's correlation test applied to all the data showed high correlation between SO42- and NO3-, indicating a common anthropogenic origin. In addition, the correlations between Na+ and Ca2+ indicated crustal origins that significantly contributed to human exposure.

Indoor air quality of low and middle income urban households in Durban, South Africa.

PubMed

Jafta, Nkosana; Barregard, Lars; Jeena, Prakash M; Naidoo, Rajen N

2017-07-01

Elevated levels of indoor air pollutants may cause cardiopulmonary disease such as lower respiratory infection, chronic obstructive lung disease and lung cancer, but the association with tuberculosis (TB) is unclear. So far the risk estimates of TB infection or/and disease due to indoor air pollution (IAP) exposure are based on self-reported exposures rather than direct measurements of IAP, and these exposures have not been validated. The aim of this paper was to characterize and develop predictive models for concentrations of three air pollutants (PM 10 , NO 2 and SO 2 ) in homes of children participating in a childhood TB study. Children younger than 15 years living within the eThekwini Municipality in South Africa were recruited for a childhood TB case control study. The homes of these children (n=246) were assessed using a walkthrough checklist, and in 114 of them monitoring of three indoor pollutants was also performed (sampling period: 24h for PM 10 , and 2-3 weeks for NO 2 and SO 2 ). Linear regression models were used to predict PM 10 and NO 2 concentrations from household characteristics, and these models were validated using leave out one cross validation (LOOCV). SO 2 concentrations were not modeled as concentrations were very low. Mean indoor concentrations of PM 10 (n=105) , NO 2 (n=82) and SO 2 (n=82) were 64μg/m 3 (range 6.6-241); 19μg/m 3 (range 4.5-55) and 0.6μg/m 3 (range 0.005-3.4) respectively with the distributions for all three pollutants being skewed to the right. Spearman correlations showed weak positive correlations between the three pollutants. The largest contributors to the PM 10 predictive model were type of housing structure (formal or informal), number of smokers in the household, and type of primary fuel used in the household. The NO 2 predictive model was influenced mostly by the primary fuel type and by distance from the major roadway. The coefficients of determination (R 2 ) for the models were 0.41 for PM 10 and 0.31 for NO 2 . Spearman correlations were significant between measured vs. predicted PM 10 and NO 2 with coefficients of 0.66 and 0.55 respectively. Indoor PM 10 levels were relatively high in these households. Both PM 10 and NO 2 can be modeled with a reasonable validity and these predictive models can decrease the necessary number of direct measurements that are expensive and time consuming. Copyright © 2017 Elsevier Inc. All rights reserved.

Chemical composition of size-segregated aerosols in Lhasa city, Tibetan Plateau

NASA Astrophysics Data System (ADS)

Wan, Xin; Kang, Shichang; Xin, Jinyuan; Liu, Bin; Wen, Tianxue; Wang, Pengling; Wang, Yuesi; Cong, Zhiyuan

2016-06-01

To reveal the chemical characteristics of size-segregated aerosols in the high-altitude city of Tibetan Plateau, eight-size aerosol samples were collected in Lhasa from March 2013 to February 2014. The annual mean of online PM2.5 was 25.0 ± 16.0 μg m- 3, which was much lower than Asian cities but similar with some European cities. The annual mean concentrations of organic carbon (OC, 7.92 μg m- 3 in PM2.1 and 12.66 μg m- 3 in PM9.0) and elemental carbon (EC, 1.00 μg m- 3 in PM2.1 and 1.21 μg m- 3 in PM9.0) in Lhasa aerosols were considerably lower than those heavily polluted cities such as Beijing and Xi'an, China and Kathmandu, Nepal. Sulfate, NO3-, NH4+ and Ca2 + were 0.75 ± 0.31, 0.82 ± 0.35, 0.38 ± 0.34 and 0.57 ± 0.29 μg m- 3 in fine particles while in coarse particles they were 0.57 ± 0.37, 0.73 ± 0.23, 0.07 ± 0.03 and 2.52 ± 1.37 μg m- 3, respectively. Secondary water-soluble ions composed 35.8% of the total ionic components in fine particles according to the established electroneutrality, while in coarse particles they took up only 9.3%. Ca2 + (40.6%) was the major component of the coarse particles. For seasonality, the concentrations of OC, EC, SO42 -, NH4+, K+, Ca2 +, Mg2 +, Cl- and Na+ presented higher values during late autumn and winter but were relatively lower in spring and summer. Nevertheless, NO3- was considerably higher in summer and autumn, presumably due to increased tourist-vehicle emissions. During winter and spring, [Ca2 +]/[NO3-+ SO42 -] ratios in coarse particles showed higher values of 7.31 and 6.17, respectively, emphasizing the dust influence. [NO3-]/[SO42 -] ratios in fine particles during spring, summer and autumn exceeding 1 indicated that the currently predominant vehicle exhaust makes a greater contribution to the aerosols. While more stationary sources such as coal and biomass burning existed in winter since the [NO3-]/[SO42 -] ratio was less than 1. Different sources and formation processes lead to a bimodal size distribution (0-0.65 μm in fine particles and 4.7-9.0 μm in coarse particles) for all of the compounds except Na+.

Characterization and source analysis of water-soluble inorganic ionic species in PM2.5 in Taiyuan city, China

NASA Astrophysics Data System (ADS)

He, Qiusheng; Yan, Yulong; Guo, Lili; Zhang, Yanli; Zhang, Guixiang; Wang, Xinming

2017-02-01

PM2.5 samples were collected in urban area in Taiyuan for four seasons from August 2009 to April 2010. The Water-soluble inorganic ions (WSI, including F-, Cl-, NO3-, SO42 -, Na+, NH4+, K+, Mg2 +, and Ca2 +) were analyzed by ion chromatography. The daily PM2.5 levels in the field samples varied from 49.90 to 477.93 μg/m3 with the mean of 209.54 μg/m3, which all largely exceeded the PM2.5 24-hour limitation value of 35 μg/m3 in Environmental Protection Administration of United States and 75 μg/m3 in Ministry of Environmental Protection of China. The WSI average concentration was 68.86 μg/m3 and accounted for about 32.86% of PM2.5. As the most abundant anion and cation, SO42 - and NH4+ were 43.53 and 14.78 percent of WSI, respectively. PM2.5 in Taiyuan was acidic by the micro-equivalents concentration methods but nearly neutral in autumn, and the chemical forms of WSI were mainly NH4HSO4, (NH4)2SO4 and NH4NO3. PM2.5 and WSI levels showed obvious seasonal variation and were the highest in winter in all samples. PM2.5, SO42 -, and some coal-related ions such as NH4+ and Cl- were higher in winter than other seasons, which mainly attributed to more coal combustion for power and indoor heating supply. The ratio analysis showed that Mg2 + and Ca2 + were not only from soil dust, but also from coal combustion and industry emission. Biomass burning such as the cornstalk and tree branches led to the highest K+ emission in autumn and summer. Wind had a regular influence on the PM2.5 and WSI, and would transport the soil dust mainly from the northwest and also lead to re-suspension of dust in the air when the wind speed was high. Furthermore, the dustpan topography easily helped the pollutants to concentrate in Taiyuan city, and some coal coking industries might contribute to high PM2.5 and WSI in Taiyuan.

Chemical composition of aerosol, sea fog, and rainwater in the marine boundary layer of the northwestern North Pacific and its marginal seas

NASA Astrophysics Data System (ADS)

Sasakawa, Motoki; Uematsu, Mitsuo

2002-12-01

Samples of aerosol, sea fog, and rainwater were collected during a research cruise in the northwestern North Pacific, the Sea of Okhotsk, and the Sea of Japan in the summer of 1998. High concentrations of NO3-, nss-SO42- and NH4+ in aerosol over the Sea of Japan suggest that anthropogenic substances were transported to this region. Although the Sea of Okhotsk was covered with a clean marine air mass, the concentration of nss-SO42- was comparatively high in the aerosol samples. This nss-SO42- is probably of marine biogenic origin. The pH values of fogwater samples were measured to be <3.0 over the Sea of Okhotsk and the Sea of Japan. The concentrations of NO3- and NH4+ in the fogwater collected over the Sea of Japan were higher than those in the other regions, suggesting that the sea fog scavenged anthropogenic substances. The concentration of nss-SO42- in fogwater over the Sea of Okhotsk was equivalent to that over the Sea of Japan, probably because nss-SO42- and SO2 of marine biogenic origin were scavenged by the sea fog over the Sea of Okhotsk. The pH values of rainwater samples ranged from 6.1 to 7.2 during the cruise, and acidification of the rain was not significant. The concentrations of nss-Ca2+ in the rainwater were higher than those of the fogwater. This suggests that the rain-scavenged continental CaCO3 may have existed above the lower marine boundary layer, where sea fog appeared. Comparisons of the composition of aerosol and fogwater indicated that coarse particles, such as sea salts predominantly act as condensation nuclei of sea fog droplets rather than fine particles such as (NH4)2SO4.

A new method of calculating electrical conductivity with applications to natural waters

USGS Publications Warehouse

McCleskey, R. Blaine; Nordstrom, D. Kirk; Ryan, Joseph N.; Ball, James W.

2012-01-01

A new method is presented for calculating the electrical conductivity of natural waters that is accurate over a large range of effective ionic strength (0.0004–0.7 mol kg-1), temperature (0–95 °C), pH (1–10), and conductivity (30–70,000 μS cm-1). The method incorporates a reliable set of equations to calculate the ionic molal conductivities of cations and anions (H+, Li+, Na+, K+, Cs+, NH4+, Mg2+, Ca2+, Sr2+, Ba2+, F-, Cl-, Br-, SO42-, HCO3-, CO32-, NO3-, and OH-), environmentally important trace metals (Al3+, Cu2+, Fe2+, Fe3+, Mn2+, and Zn2+), and ion pairs (HSO4-, NaSO4-, NaCO3-, and KSO4-). These equations are based on new electrical conductivity measurements for electrolytes found in a wide range of natural waters. In addition, the method is coupled to a geochemical speciation model that is used to calculate the speciated concentrations required for accurate conductivity calculations. The method was thoroughly tested by calculating the conductivities of 1593 natural water samples and the mean difference between the calculated and measured conductivities was -0.7 ± 5%. Many of the samples tested were selected to determine the limits of the method and include acid mine waters, geothermal waters, seawater, dilute mountain waters, and river water impacted by municipal waste water. Transport numbers were calculated and H+, Na+, Ca2+, Mg2+, NH4+, K+, Cl-, SO42-, HCO3-, CO32-, F-, Al3+, Fe2+, NO3-, and HSO4- substantially contributed (>10%) to the conductivity of at least one of the samples. Conductivity imbalance in conjunction with charge imbalance can be used to identify whether a cation or an anion measurement is likely in error, thereby providing an additional quality assurance/quality control constraint on water analyses.

A new method of calculating electrical conductivity with applications to natural waters

NASA Astrophysics Data System (ADS)

McCleskey, R. Blaine; Nordstrom, D. Kirk; Ryan, Joseph N.; Ball, James W.

2012-01-01

A new method is presented for calculating the electrical conductivity of natural waters that is accurate over a large range of effective ionic strength (0.0004-0.7 mol kg-1), temperature (0-95 °C), pH (1-10), and conductivity (30-70,000 μS cm-1). The method incorporates a reliable set of equations to calculate the ionic molal conductivities of cations and anions (H+, Li+, Na+, K+, Cs+, NH4+, Mg2+, Ca2+, Sr2+, Ba2+, F-, Cl-, Br-, SO42-, HCO3-, CO32-, NO3-, and OH-), environmentally important trace metals (Al3+, Cu2+, Fe2+, Fe3+, Mn2+, and Zn2+), and ion pairs (HSO4-, NaSO4-, NaCO3-, and KSO4-). These equations are based on new electrical conductivity measurements for electrolytes found in a wide range of natural waters. In addition, the method is coupled to a geochemical speciation model that is used to calculate the speciated concentrations required for accurate conductivity calculations. The method was thoroughly tested by calculating the conductivities of 1593 natural water samples and the mean difference between the calculated and measured conductivities was -0.7 ± 5%. Many of the samples tested were selected to determine the limits of the method and include acid mine waters, geothermal waters, seawater, dilute mountain waters, and river water impacted by municipal waste water. Transport numbers were calculated and H+, Na+, Ca2+, Mg2+, NH4+, K+, Cl-, SO42-, HCO3-, CO32-, F-, Al3+, Fe2+, NO3-, and HSO4-substantially contributed (>10%) to the conductivity of at least one of the samples. Conductivity imbalance in conjunction with charge imbalance can be used to identify whether a cation or an anion measurement is likely in error, thereby providing an additional quality assurance/quality control constraint on water analyses.

Inhibition of bacterial oxidation of ferrous iron by lead nitrate in sulfate-rich systems

USGS Publications Warehouse

Wang, Hongmei; Gong, Linfeng; Cravotta,, Charles A.; Yang, Xiaofen; Tuovinen, Olli H.; Dong, Hailiang; Fu, Xiang

2013-01-01

Inhibition of bacterial oxidation of ferrous iron (Fe(II)) by Pb(NO3)2 was investigated with a mixed culture of Acidithiobacillus ferrooxidans. The culture was incubated at 30 °C in ferrous-sulfate medium amended with 0–24.2 mM Pb(II) added as Pb(NO3)2. Anglesite (PbSO4) precipitated immediately upon Pb addition and was the only solid phase detected in the abiotic controls. Both anglesite and jarosite (KFe3(SO4)2(OH)6) were detected in inoculated cultures. Precipitation of anglesite maintained dissolved Pb concentrations at 16.9–17.6 μM regardless of the concentrations of Pb(NO3)2 added. Fe(II) oxidation was suppressed by 24.2 mM Pb(NO3)2 addition even when anglesite was removed before inoculation. Experiments with 0–48 mM KNO3 demonstrated that bacterial Fe(II) oxidation decreased as nitrate concentration increased. Therefore, inhibition of Fe(II) oxidation at 24.2 mM Pb(NO3)2 addition resulted from nitrate toxicity instead of Pb addition. Geochemical modeling that considered the initial precipitation of anglesite to equilibrium followed by progressive oxidation of Fe(II) and the precipitation of jarosite and an amorphous iron hydroxide phase, without allowing plumbojarosite to precipitate were consistent with the experimental time-series data on Fe(II) oxidation under biotic conditions. Anglesite precipitation in mine tailings and other sulfate-rich systems maintains dissolved Pb concentrations below the toxicity threshold of A. ferrooxidans.

Thermal decomposition of europium sulfates Eu2(SO4)3·8H2O and EuSO4

NASA Astrophysics Data System (ADS)

Denisenko, Yu. G.; Khritokhin, N. A.; Andreev, O. V.; Basova, S. A.; Sal'nikova, E. I.; Polkovnikov, A. A.

2017-11-01

Reactions of europium sulfates Eu2(SO4)3·8H2O and EuSO4 complete decomposition were studied by Simultaneous Thermal Analysis. It was revealed that one-step dehydratation of Eu2(SO4)3·8H2O crystallohydrate is accompanied by the formation of amorphous anhydrous europium sulfate Eu2(SO4)3. Crystallization of amorphous europium (III) sulfate occurs at 381.1 °C (in argon) and 391.3 °C (in air). The average enthalpy values for dehydratation reaction of Eu2(SO4)3·8H2O (ΔH° = 141.1 kJ/mol), decomposition reactions of Eu2(SO4)3 (ΔH = 463.1 kJ/mol), Eu2O2SO4 (ΔH = 378.4 kJ/mol) and EuSO4 (ΔH = 124.1 kJ/mol) were determined. The step process mechanisms of thermal decomposition of europium (III) sulfate in air and europium (II) sulfate in inert atmosphere were established and justified. The kinetic parameters of complete thermal decomposition of europium (III) sulfate octahydrate were calculated by Kissinger model. The standard enthalpies of compound formation were calculated using thermal effects and formation enthalpy data for binary compounds.

Bobjonesite, V4+ O (SO4) (H2O 3, a new mineral species from Temple Mountain, Emery County, Utah, U.S.A

USGS Publications Warehouse

Schindler, M.; Hawthorne, F.C.; Huminicki, D.M.C.; Haynes, P.; Grice, Joel D.; Evans, H.T.

2003-01-01

Bobjonesite, V4+ O (SO4) (H2O 3, is a new mineral species from Temple Mountain, Emery County, Utah, U.S.A. It occurs as blue-green crusts and efflorescences in fractures in a fossil (Triassic) tree: individual crystals are ??1 mm and are intimately intergrown. Bobjonesite hydrates very easily, and is unstable in all but the driest atmosphere. Its structure was determined on a crystal of bobjonesite: however, the physical properties, optical properties and X-ray powder-diffraction pattern were recorded on the synthetic equivalent, and an electron-microprobe analysis was not possible. Bobjonesite has a pale blue streak, a vitreous luster and no observable fluorescence under ultraviolet light. It has no cleavage or parting. The Mohs hardness is ???1, and the calculated density is 2.28 g/cm3. Bobjonesite is biaxial positive, with ?? 1.555(2 , ?? 1.561(1), ?? 1.574(2), 2V(obs.) = 72(1)??, 2V(calc.) = 69??; it is non-pleochroic, X = b, Y ??? 19?? (in ?? obtuse). Bobjonesite is monoclinic, space group P21/n, cell dimensions from single-crystal data: a 7.3940(5), b 7.4111(3), c 12.0597(9) A??, ?? 106.55(1)??, V 633.5(1) A??3, Z=4. The strongest seven lines in the X-ray powder-diffraction pattern [d in A??(I)(hkl)] are as follows: 5.795(100)(002), 3.498(90)(112), 3.881(48)(1??03), 5.408(37) (101), 4.571(20)(012), 6.962(11 (1??01) and 6.254(11)(011). The chemical formula was derived from crystal-structure analysis; the end-member formula is V O (SO4) (H2O)3. The crystal structure of bobjonesite was refined to an R index of 3.6% for 1105 observed (Fo> 5??F) reflections measured with an automated four-circle X-ray diffractometer using MoK?? X-radiation. There is one V site occupied by V4+ and surrounded by three O atoms and three (H2O) groups in an octahedral arrangement, with one short vanadyl bond (1.577 A??), four similar equatorial bonds (<2.022 A??), and one longer V-O bond (2.278 A??) trans to the vanadyl bond. The structure consists of isolated [V4+2 O2 (H2O)6 (SO4)2] clusters linked by hydrogen bonds.

Removal of nitrate and sulphate from biologically treated municipal wastewater by electrocoagulation

NASA Astrophysics Data System (ADS)

Sharma, Arun Kumar; Chopra, A. K.

2017-06-01

The present investigation observed the effect of current density ( j), electrocoagulation (EC) time, inter electrode distance, electrode area, initial pH and settling time on the removal of nitrate (NO3 -) and sulphate (SO4 2-) from biologically treated municipal wastewater (BTMW), and optimization of the operating conditions of the EC process. A glass chamber of two-liter volume was used for the experiments with DC power supply using two electrode plates of aluminum (Al-Al). The maximum removal of NO3 - (63.21 %) and SO4 2- (79.98 %) of BTMW was found with the optimum operating conditions: current density: 2.65 A/m2, EC time: 40 min, inter electrode distance: 0.5 cm, electrode area: 160 cm2, initial pH: 7.5 and settling time: 60 min. The EC brought down the concentration of NO3 - within desirable limit of the Bureau of Indian Standard (BIS)/WHO for drinking water. Under optimal operating conditions, the operating cost was found to be 1.01/m3 of water in terms of the electrode consumption (23.71 × 10-5 kg Al/m3) and energy consumption (101.76 kWh/m3).

A pilot study of gaseous pollutants' measurement (NO2, SO2, NH3, HNO3 and O3) in Abidjan, Côte d'Ivoire: contribution to an overview of gaseous pollution in African cities

NASA Astrophysics Data System (ADS)

Bahino, Julien; Yoboué, Véronique; Galy-Lacaux, Corinne; Adon, Marcellin; Akpo, Aristide; Keita, Sékou; Liousse, Cathy; Gardrat, Eric; Chiron, Christelle; Ossohou, Money; Gnamien, Sylvain; Djossou, Julien

2018-04-01

This work is part of the DACCIWA FP7 project (Dynamics-Aerosol-Chemistry-Cloud Interactions in West Africa) in the framework of the Work Package 2 Air Pollution and Health. This study aims to characterize urban air pollution levels through the measurement of NO2, SO2, NH3, HNO3 and O3 in Abidjan, the economic capital of Côte d'Ivoire. Measurements of inorganic gaseous pollutants, i.e. NO2, SO2, NH3, HNO3 and O3 were performed in Abidjan during an intensive campaign within the dry season (15 December 2015 to 16 February 2016), using INDAAF (International Network to study Deposition and Atmospheric chemistry in AFrica) passive samplers exposed in duplicate for 2-week periods. Twenty-one sites were selected in the district of Abidjan to be representative of various anthropogenic and natural sources of air pollution in the city. Results from this intensive campaign show that gas concentrations are strongly linked to surrounding pollution sources and show a high spatial variability. Also, NH3, NO2 and O3 gases were present at relatively higher concentrations at all the sites. NH3 average concentrations varied between 9.1 ± 1.7 ppb at a suburban site and 102.1 ± 9.1 ppb at a domestic fires site. NO2 mean concentration varied from 2.7 ± 0.1 ppb at a suburban site to 25.0 ± 1.7 ppb at an industrial site. Moreover, we measured the highest O3 concentration at the two coastal sites of Gonzagueville and Félix-Houphouët-Boigny International Airport located in the southeast of the city, with average concentrations of 19.1 ± 1.7 and 18.8 ± 3.0 ppb, respectively. The SO2 average concentration never exceeded 7.2 ± 1.2 ppb over all the sites, with 71.5 % of the sampling sites showing concentrations ranging between 0.4 and 1.9 ppb. The HNO3 average concentration ranged between 0.2 and 1.4 ppb. All these results were combined with meteorological parameters to provide the first mapping of gaseous pollutants on the scale of the district of Abidjan using geostatistical analysis (ArcGIS software). Spatial distribution results emphasize the importance of the domestic fires source and the significant impact of the traffic emissions on the scale of the city. In addition, in this work we propose a first overview of gaseous SO2 and NO2 concentrations on the scale of several African cities by comparing literature to our values. The daily SO2 standard of World Health Organization (WHO) is exceeded in most of the cities reported in the overview, with concentrations ranging from 0.2 to 3662 µg m-3. Annual NO2 concentrations ranged from 2 to 175 µg m-3, which are lower than the WHO threshold. As a conclusion, this study constitutes an original database to characterize urban air pollution and a first attempt towards presenting a spatial distribution of the pollution levels at the scale of the metropolis of Abidjan. This work should draw the attention of the African public authorities to the necessity of building an air quality monitoring network in order to (1) to define national standards and to better control the pollutants emissions and (2) to investigate the impact on the health of the growing population in developing African countries.

Impact of environmental conditions on aggregation kinetics of hematite and goethite nanoparticles

NASA Astrophysics Data System (ADS)

Xu, Chen-yang; Deng, Kai-ying; Li, Jiu-yu; Xu, Ren-kou

2015-10-01

Hematite and goethite nanoparticles were used as model minerals to investigate their aggregation kinetics under soil environmental conditions in the present study. The hydrodynamic diameters of hematite and goethite nanoparticles were 34.4 and 66.3 nm, respectively. The positive surface charges and zeta potential values for goethite were higher than for hematite. The effective diameter for goethite was much larger than for hematite due to anisotropic sticking of needle-shaped goethite during aggregation. Moreover, the critical coagulation concentration (CCC) values of nanoparticles in solutions of NaNO3, NaCl, NaF, and Na2SO4 were 79.2, 75.0, 7.8, and 0.5 mM for hematite and they were 54.7, 62.6, 5.5, and 0.2 mM for goethite, respectively. The disparity of anions in inducing hematite or goethite aggregation lay in the differences in interfacial interactions. NO3 - and Cl- could decrease the zeta potential and enhance aggregation mainly through increasing ionic strength and compressing electric double layers of hematite and goethite nanoparticles. F- and SO4 2- highly destabilized the suspensions of nanoparticles mainly through specific adsorption and then neutralizing the positive surface charges of nanoparticles. Specific adsorption of cations could increase positive surface charges and stabilize hematite and goethite nanoparticles. The Hamaker constants of hematite and goethite nanoparticles were calculated to be 2.87 × 10-20 and 2.29 × 10-20 J-1, respectively. The predicted CCC values based on DLVO theory were consistent well with the experimentally determined CCC values in NaNO3, NaCl, NaF, and Na2SO4 systems, which demonstrated that DLVO theory could successfully predict the aggregation kinetics even when specific adsorption of ions occurred.

Ion composition of coarse and fine particles in Iasi, north-eastern Romania: Implications for aerosols chemistry in the area

NASA Astrophysics Data System (ADS)

Arsene, Cecilia; Olariu, Romeo Iulian; Zarmpas, Pavlos; Kanakidou, Maria; Mihalopoulos, Nikolaos

2011-02-01

Atmospheric loadings of the aerosols coarse (particles of AED > 1.5 μm) and fine fractions (particles of AED < 1.5 μm) were determined in Iasi, north-eastern Romania from January 2007 to March 2008. Concentrations of water soluble ions (SO 42-, NO 3-, Cl -, C 2O 42-, NH 4+, K +, Na +, Ca 2+ and Mg 2+) were measured using ion chromatography (IC). In the coarse particles, calcium and carbonate are the main ionic constituents (˜65%), whereas in the fine particles SO 42-, NO 3-, Cl - and NH 4+ are the most abundant. Temperature and relative humidity (RH) associated with increased concentrations of specific ions might be the main factors controlling the aerosol chemistry at the investigated site. From August 2007 to March 2008 high RH (as high as 80% for about 82% of the investigated period) was prevailing in Iasi and the collected particles were expected to have deliquesced and form an internal mixture. We found that in fine particles ammonium nitrate (NH 4NO 3) is important especially under conditions of NH 4+/SO 42- ratio higher than 1.5 and high RH (RH above deliquescence of NH 4Cl, NH 4NO 3 and (NH 4) 2SO 4). At the investigated site large ammonium artifacts may occur due to inter-particle interaction especially under favorable meteorological conditions. A methodology for estimating the artifact free ambient ammonium concentration is proposed for filter pack sampling data of deliquesced particles. Nitrate and sulfate ions in coarse particles are probably formed via reactions of nitric and sulfuric acid with calcium carbonate and sodium chloride which during specific seasons are abundant at the investigated site. In the fine mode sulfate concentration maximized during summer (due to enhanced photochemistry) and winter (due to high concentration of SO 2 emitted from coal burning). Natural contributions, dust or sea-salt related, prevail mainly in the coarse particles. From May 2007 to August 2007, when air masses originated mainly from Black Sea, in the coarse particles an nss-Cl/Na ratio of 1.11 was measured. Elevated levels of chloride in fine particles have been attributed to waste burning in the proximity of the investigated site or to NaCl salt widely spread on roads during winter. Considering the importance of atmospheric aerosols, this study may constitute a reference point for Eastern Europe.

Groundwater quality from a part of Prakasam District, Andhra Pradesh, India

NASA Astrophysics Data System (ADS)

Subba Rao, N.

2018-03-01

Quality of groundwater is assessed from a part of Prakasam district, Andhra Pradesh, India. Groundwater samples collected from thirty locations from the study area were analysed for pH, electrical conductivity (EC), total dissolved solids (TDS), calcium (Ca2+), magnesium (Mg2+), sodium (Na+), potassium (K+), bicarbonate ( {HCO}3^{ - } ), chloride (Cl-), sulphate ( {SO}4^{2 - } ), nitrate ( {NO}3^{ - } ) and fluoride (F-). The results of the chemical analysis indicate that the groundwater is alkaline in nature and are mainly characterized by Na+- {HCO}3^{ - } and Na+-Cl- facies. Groundwater chemistry reflects the dominance of rock weathering and is subsequently modified by human activities, which are supported by genetic geochemical evolution and hydrogeochemical relations. Further, the chemical parameters (pH, TDS, Ca2+, Mg2+, Na+, {HCO}3^{ - } , Cl-, {SO}4^{2 - } , {NO}3^{ - } and F-) were compared with the drinking water quality standards. The sodium adsorption ratio, percent sodium, permeability index, residual sodium carbonate, magnesium ratio and Kelly's ratio were computed and USSL, Wilcox and Doneen's diagrams were also used for evaluation of groundwater quality for irrigation. For industrial purpose, the pH, TDS, {HCO}3^{ - } , Cl- and {SO}4^{2 - } were used to assess the impact of incrustation and corrosion activities on metal surfaces. As a whole, it is observed that the groundwater quality is not suitable for drinking, irrigation and industrial purposes due to one or more chemical parameters exceeding their standard limits. Therefore, groundwater management measures were suggested to improve the water quality.

Chemical characterization of extractable water soluble matter associated with PM10 from Mexico City during 2000.

PubMed

Gutiérrez-Castillo, M E; Olivos-Ortiz, M; De Vizcaya-Ruiz, A; Cebrián, M E

2005-11-01

We report the chemical composition of PM10-associated water-soluble species in Mexico City during the second semester of 2000. PM10 samples were collected at four ambient air quality monitoring sites in Mexico City. We determined soluble ions (chloride, nitrate, sulfate, ammonium, sodium, potassium), ionizable transition metals (Zn, Fe, Ti, Pb, Mn, V, Ni, Cr, Cu) and soluble protein. The higher PM(10) levels were observed in Xalostoc (45-174 microg m(-3)) and the lowest in Pedregal (19-54 microg m(-3)). The highest SO2 average concentrations were observed in Tlalnepantla, NO2 in Merced and O3 and NO(x) in Pedregal. The concentration range of soluble sulfate was 6.7-7.9 and 19-25.5 microg m(-3) for ammonium, and 14.8-29.19 for soluble V and 3.2-7.7 ng m(-3) for Ni, suggesting a higher contribution of combustion sources. PM-associated soluble protein levels varied between 0.038 and 0.169 mg m(-3), representing a readily inhalable constituent that could contribute to adverse outcomes. The higher levels for most parameters studied were observed during the cold dry season, particularly in December. A richer content of soluble metals was observed when they were expressed by mass/mass units rather than by air volume units. Significant correlations between Ni-V, Ni-SO4(-2), V-SO4(-2), V-SO2, Ni-SO2 suggest the same type of emission source. The variable soluble metal and ion concentrations were strongly influenced by the seasonal meteoclimatic conditions and the differential contribution of emission sources. Our data support the idea that PM10 mass concentration by itself does not provide a clear understanding of a local PM air pollution problem.

NOAA PMEL Station Chemistry Data

DOE Data Explorer

Quinn, Patricia

2008-04-04

Submicron and supermicron samples are analyzed by ion chromatography for Cl-, NO3-, SO4-2, Na+, NH4+, K+, Mg2+, and Ca+2. The analysis of MSA-, Br-, and oxalate has been added to some stations. Samples also are analyzed for total mass by gravimetric analysis at 55 +/- 5% RH.

A heptadecanuclear Mn(III)9Dy(III)8 cluster derived from triethanolamine with two edge sharing supertetrahedra as the core and displaying SMM behaviour.

PubMed

Langley, Stuart K; Moubarakia, Boujemaa; Murray, Keith S

2010-06-07

A heterometallic, heptadecanuclear cluster of formula [Mn(III)9Dy(III)8O8(OH)8(tea)2(teaH)2(teaH2)4(Ac)4(NO3)2(H2O)4](NO3)7·8H2O (1) is reported. The core of 1 displays two edge sharing Mn(III)5Dy(III)5 supertetrahedra and represents one of the largest Mn/4f cluster compound so far reported. Magnetic studies show that 1 displays probable SMM behaviour as observed via non-zero values in the χM''vs T plot.

Assessment of the quality of water from hand-dug wells in ghana.

PubMed

Nkansah, Marian Asantewah; Boadi, Nathaniel Owusu; Badu, Mercy

2010-04-26

This study focused upon the determination of physicochemical and microbial properties, including metals, selected anions and coliform bacteria in drinking water samples from hand-dug wells in the Kumasi metropolis of the Republic of Ghana. The purpose was to assess the quality of water from these sources. Ten different water samples were taken from different parts of Kumasi, the capital of the Ashanti region of Ghana and analyzed for physicochemical parameters including pH, electrical conductivity, total dissolved solids, alkalinity total hardness and coliform bacteria. Metals and anions analyzed were Ca, Mg, Fe, Mn, NO(3) (-), NO(2) (-), SO(4) (2-), PO(4) (2-), F(-) and Cl(-). Bacteria analysed were total coliform and Escherichia coli.THE DATA SHOWED VARIATION OF THE INVESTIGATED PARAMETERS IN SAMPLES AS FOLLOWS: pH, 6.30-0.70; conductivity (EC), 46-682 muS/cm; PO(4) (3-), 0.67-76.00 mg/L; F(-), 0.20-0.80 mg/L; NO(3) (-), 0-0.968 mg/L; NO(2) (-), 0-0.063 mg/L; SO(4) (2-), 3.0-07.0 mg/L; Fe, 0-1.2 mg/L; Mn, 0-0.018 mg/L. Total coliform and Escherichia coli were below the minimum detection limit (MDL) of 20 MPN per 100 ml in all the samples. The concentrations of most of the investigated parameters in the drinking water samples from Ashanti region were within the permissible limits of the World Health Organization drinking water quality guidelines.

Assessment of roadside surface water quality of Savar, Dhaka, Bangladesh using GIS and multivariate statistical techniques

NASA Astrophysics Data System (ADS)

Ahmed, Fahad; Fakhruddin, A. N. M.; Imam, MD. Toufick; Khan, Nasima; Abdullah, Abu Tareq Mohammad; Khan, Tanzir Ahmed; Rahman, Md. Mahfuzur; Uddin, Mohammad Nashir

2017-11-01

In this study, multivariate statistical techniques in collaboration with GIS are used to assess the roadside surface water quality of Savar region. Nineteen water samples were collected in dry season and 15 water quality parameters including TSS, TDS, pH, DO, BOD, Cl-, F-, NO3 2-, NO2 -, SO4 2-, Ca, Mg, K, Zn and Pb were measured. The univariate overview of water quality parameters are TSS 25.154 ± 8.674 mg/l, TDS 840.400 ± 311.081 mg/l, pH 7.574 ± 0.256 pH unit, DO 4.544 ± 0.933 mg/l, BOD 0.758 ± 0.179 mg/l, Cl- 51.494 ± 28.095 mg/l, F- 0.771 ± 0.153 mg/l, NO3 2- 2.211 ± 0.878 mg/l, NO2 - 4.692 ± 5.971 mg/l, SO4 2- 69.545 ± 53.873 mg/l, Ca 48.458 ± 22.690 mg/l, Mg 19.676 ± 7.361 mg/l, K 12.874 ± 11.382 mg/l, Zn 0.027 ± 0.029 mg/l, Pb 0.096 ± 0.154 mg/l. The water quality data were subjected to R-mode PCA which resulted in five major components. PC1 explains 28% of total variance and indicates the roadside and brick field dust settle down (TDS, TSS) in the nearby water body. PC2 explains 22.123% of total variance and indicates the agricultural influence (K, Ca, and NO2 -). PC3 describes the contribution of nonpoint pollution from agricultural and soil erosion processes (SO4 2-, Cl-, and K). PC4 depicts heavy positively loaded by vehicle emission and diffusion from battery stores (Zn, Pb). PC5 depicts strong positive loading of BOD and strong negative loading of pH. Cluster analysis represents three major clusters for both water parameters and sampling sites. The site based on cluster showed similar grouping pattern of R-mode factor score map. The present work reveals a new scope to monitor the roadside water quality for future research in Bangladesh.

Effects of pH on the formation of 4(5)-Methylimidazole in glucose/ammonium sulfate and glucose/ammonium sulfite caramel model reactions.

PubMed

Wu, Xinlan; Kong, Fansheng; Huang, Minghui; Yu, Shujuan

2015-10-01

The objective of the present study was to detail the change of 4(5)-Methylimidazole (4-MI) in sulfite and sulfate reactions with different initial pH values. Glucose/ammonium sulfate and glucose/ammonium sulfite reaction systems with initial pH conditions 4.9, 5.9, 6.9, 8.0 and 8.6, were heated at 100°C for 2h, respectively. Higher concentration of methylglyoxal (MGO) and 4-MI was detected in thermal treated glucose/ammonium sulfite reaction system than that in sulfate system. The SO 3 2- reacting with MGO and other precursors of 4-MI at higher pH conditions prevented 4-MI formation. However, no inhibition of 4-MI was found at lower pH conditions due to higher reactivity of the nucleophilic NH 4 + than SO 3 2- . The browning intensity of the sulfite system changed scarcely at higher pH values, which was possibly caused by the polyreaction between SO 3 2- and carbonyl, instead of the intermolecular polymerisation of carbonyl in the advanced stage of the Maillard reaction. Copyright © 2015 Elsevier Ltd. All rights reserved.

Probabilistic model for the spoilage wine yeast Dekkera bruxellensis as a function of pH, ethanol and free SO2 using time as a dummy variable.

PubMed

Sturm, M E; Arroyo-López, F N; Garrido-Fernández, A; Querol, A; Mercado, L A; Ramirez, M L; Combina, M

2014-01-17

The present study uses a probabilistic model to determine the growth/no growth interfaces of the spoilage wine yeast Dekkera bruxellensis CH29 as a function of ethanol (10-15%, v/v), pH (3.4-4.0) and free SO2 (0-50 mg/l) using time (7, 14, 21 and 30 days) as a dummy variable. The model, built with a total of 756 growth/no growth data obtained in a simile wine medium, could have application in the winery industry to determine the wine conditions needed to inhibit the growth of this species. Thereby, at 12.5% of ethanol and pH 3.7 for a growth probability of 0.01, it is necessary to add 30 mg/l of free SO2 to inhibit yeast growth for 7 days. However, the concentration of free SO2 should be raised to 48 mg/l to achieve a probability of no growth of 0.99 for 30 days under the same wine conditions. Other combinations of environmental variables can also be determined using the mathematical model depending on the needs of the industry. Copyright © 2013 Elsevier B.V. All rights reserved.

Integrated dry NO{sub x}/SO{sub 2} emissions control system performance summary

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hunt, T.; Muzio, L.J.; Smith, R.

1997-12-31

The Integrated Dry NO{sub x}/SO{sub 2} Emissions Control System was installed at Public Service Company of Colorado`s Arapahoe 4 generating station in 1992 in cooperation with the US Department of Energy (DOE) and the Electric Power Research Institute (EPRI). This full-scale 100 MWe demonstration combines low-NO{sub x} burners, overfire, air, and selective non-catalytic reduction (SNCR) for NO{sub x} control and dry sorbent injection (DSI) with or without humidification for SO{sub 2} control. Operation and testing of the Integrated Dry NO{sub x}/SO{sub 2} Emissions Control System began in August 1992 and will continue through 1996. Results of the NO{sub x} controlmore » technologies show that the original system goal of 70% NO{sub x} removal has been easily met and the combustion and SNCR systems can achieve NO{sub x} removals of up to 80% at full load. Duct injection of commercial calcium hydroxide has achieved a maximum SO{sub 2} removal of nearly 40% while humidifying the flue gas to a 20 F approach to saturation. Sodium-based dry sorbent injection has provided SO{sub 2} removal of over 70% without the occurrence of a visible NO{sub 2} plume. Recent test work has improved SNCR performance at low loads and has demonstrated that combined dry sodium injection and SNCR yields both lower NO{sub 2} levels and NH{sub 3} slip than either technology alone.« less

Silver(I) complexes of the weakly coordinating solvents SO(2) and CH(2)Cl(2): crystal structures, bonding, and energetics of [Ag(OSO)][Al{OC(CF(3))(3)}(4)], [Ag(OSO)(2/2)][SbF(6)], and [Ag(CH(2)Cl(2))(2)][SbF(6)].

PubMed

Decken, Andreas; Knapp, Carsten; Nikiforov, Grigori B; Passmore, Jack; Rautiainen, J Mikko; Wang, Xinping; Zeng, Xiaoqing

2009-06-22

Pushing the limits of coordination chemistry: The most weakly coordinated silver complexes of the very weakly coordinating solvents dichloromethane and liquid sulfur dioxide were prepared. Special techniques at low temperatures and the use of weakly coordinating anions allowed structural characterization of [Ag(OSO)][Al{OC(CF(3))(3)}(4)], [Ag(OSO)(2/2)][SbF(6)], and [Ag(Cl(2)CH(2))(2)][SbF(6)] (see figure). An investigation of the bonding shows that these complexes are mainly stabilized by electrostatic monopole-dipole interactions.The synthetically useful solvent-free silver(I) salt Ag[Al(pftb)(4)] (pftb=--OC(CF(3))(3)) was prepared by metathesis reaction of Li[Al(pftb)(4)] with Ag[SbF(6)] in liquid SO(2). The solvated complexes [Ag(OSO)][Al(pftb)(4)], [Ag(OSO)(2/2)][SbF(6)], and [Ag(CH(2)Cl(2))(2)][SbF(6)] were prepared and isolated by special techniques at low temperatures and structurally characterized by single-crystal X-ray diffraction. The SO(2) complexes provide the first examples of coordination of the very weak Lewis base SO(2) to silver(I). The SO(2) molecule in [Ag(OSO)][Al(pftb)(4)] is eta(1)-O coordinated to Ag(+), while the SO(2) ligands in [Ag(OSO)(2/2)][SbF(6)] bridge two Ag(+) ions in an eta(2)-O,O' (trans,trans) manner. [Ag(CH(2)Cl(2))(2)][SbF(6)] contains [Ag(CH(2)Cl(2))(2)](+) ions linked through [SbF(6)](-) ions to give a polymeric structure. The solid-state silver(I) ion affinities (SIA) of SO(2) and CH(2)Cl(2), based on bond lengths and corresponding valence units in the corresponding complexes and tensimetric titrations of Ag[Al(pftb)(4)] and Ag[SbF(6)] with SO(2) vapor, show that SO(2) is a weaker ligand to Ag(+) than the commonly used weakly coordinating solvent CH(2)Cl(2) and indicated that binding strength of SO(2) to silver(I) in the silver(I) salts increases with increasing size of the corresponding counteranion ([Al(pftb)(4)](-)>[SbF(6)](-)). The experimental findings are in good agreement with theoretical gas-phase ligand-binding energies of [Ag(L)(n)](+) (L=SO(2), CH(2)Cl(2); n=1, 2) and solid-state enthalpies obtained from Born-Fajans-Haber cycles by using the volume-based thermodynamics (VBT) approach. Bonding analysis (VB, NBO, MO) of [Ag(L)(n)](+) suggests that these complexes are almost completely stabilized by electrostatic interaction, that is, monopole-dipole interaction, with almost no covalent contribution by electron donation from the ligand orbitals into the vacant 5s orbital of Ag(+). All experimental findings and theoretical considerations demonstrate that SO(2) is less covalently bound to Ag(+) than CH(2)Cl(2) and support the thesis that SO(2) is a polar but non-coordinating solvent towards Ag(+).

Effects of properties of manganese oxide-impregnated catalysts and flue gas condition on multipollutant control of Hg0 and NO.

PubMed

Chiu, Chun-Hsiang; Hsi, Hsing-Cheng; Lin, Hong-Ping; Chang, Tien-Chin

2015-06-30

This research investigated the effects of manganese oxide (MnOx) impregnation on the physical/chemical properties and multi pollutant control effectiveness of Hg(0) and NO using a V2O5-WO3/TiO2-SiO2 selective catalytic reduction (SCR) catalyst. Raw and MnOx-treated SCR samples were bean-shaped nanoparticles with sizes within 10-30 nm. Impregnating MnOx of ≤ 5 wt% caused limited changes in physical properties of the catalyst. The decrease in surface area when the impregnated MnOx amount was 10 wt% may stem from the pore blockage and particle growth or aggregation of the catalyst. Mn(4+) was the main valence state of impregnated MnOx. Apparent crystallinity of MnOx was not observed based on X-ray diffraction. MnOx impregnation enhanced the Hg(0) oxidation and NO/SO2 removal of SCR catalyst. The 5 and 10% MnOx-impregnated samples had the greatest multi pollutant control potentials for Hg(0) oxidation and NO removal; however, the increasing SO2 removal that may be mainly due to SO2-SO3 conversion should be cautioned. HCl and O2 greatly promoted Hg(0) oxidation. SO2 enhanced Hg(0) oxidation at ≤ 200 ppm while NO and NH3 consistently inhibited Hg(0) oxidation. Elevating flue gas temperature enhanced Hg(0) oxidation. Overall, MnOx-impregnated catalysts show stable and consistent multi pollutant removal effectiveness under the test conditions. Copyright © 2015 Elsevier B.V. All rights reserved.

Size distribution and sources of humic-like substances in particulate matter at an urban site during winter.

PubMed

Park, Seungshik; Son, Se-Chang

2016-01-01

This study investigates the size distribution and possible sources of humic-like substances (HULIS) in ambient aerosol particles collected at an urban site in Gwangju, Korea during the winter of 2015. A total of 10 sets of size-segregated aerosol samples were collected using a 10-stage Micro-Orifice Uniform Deposit Impactor (MOUDI), and the samples were analyzed to determine the mass as well as the presence of ionic species (Na(+), NH4(+), K(+), Ca(2+), Mg(2+), Cl(-), NO3(-), and SO4(2-)), water-soluble organic carbon (WSOC) and HULIS. The separation and quantification of the size-resolved HULIS components from the MOUDI samples was accomplished using a Hydrophilic-Lipophilic Balanced (HLB) solid phase extraction method and a total organic carbon analyzer, respectively. The entire sampling period was divided into two periods: non-Asian dust (NAD) and Asian dust (AD) periods. The contributions of water-soluble organic mass (WSOM = 1.9 × WSOC) and HULIS (=1.9 × HULIS-C) to fine particles (PM1.8) were approximately two times higher in the NAD samples (23.2 and 8.0%) than in the AD samples (12.8 and 4.2%). However, the HULIS-C/WSOC ratio in PM1.8 showed little difference between the NAD (0.35 ± 0.07) and AD (0.35 ± 0.05) samples. The HULIS exhibited a uni-modal size distribution (@0.55 μm) during NAD and a bimodal distribution (@0.32 and 1.8 μm) during AD, which was quite similar to the mass size distributions of particulate matter, WSOC, NO3(-), SO4(2-), and NH4(+) in both the NAD and AD samples. The size distribution characteristics and the results of the correlation analyses indicate that the sources of HULIS varied according to the particle size. In the fine mode (≤1.8 μm), the HULIS composition during the NAD period was strongly associated with secondary organic aerosol (SOA) formation processes similar to those of secondary ionic species (cloud processing and/or heterogeneous reactions) and primary emissions during the biomass burning period, and during the AD period, it was only associated with SOA formation. In the coarse mode (3.1-10 μm), it was difficult to identify the HULIS sources during the NAD period, and during the AD period, the HULIS was most likely associated with soil-related particles [Ca(NO3]2 and CaSO4) and/or sea-salt particles (NaNO3 and Na2SO4).

Trithallium hydrogen bis(sulfate), Tl(3)H(SO(4))(2), in the super-ionic phase by X-ray powder diffraction.

PubMed

Matsuo, Yasumitsu; Kawachi, Shinya; Shimizu, Yuya; Ikehata, Seiichiro

2002-07-01

The structure of trithallium hydrogen bis(sulfate), Tl(3)H(SO(4))(2), in the super-ionic phase has been analyzed by Rietveld analysis of the X-ray powder diffraction pattern. Atomic parameters based on the isotypic Rb(3)H(SeO(4))(2) crystal in space group R3m in the super-ionic phase were used as the starting model, because it has been shown from the comparison of thermal and electric properties in Tl(3)H(SO(4))(2) and M(3)H(SO(4))(2) type crystals (M = Rb, Cs or NH(4)) that the room-temperature Tl(3)H(SO(4))(2) phase is isostructural with the high-temperature R3m-symmetry M(3)H(SO(4))(2) crystals. The structure was determined in the trigonal space group R3m and the Rietveld refinement shows that an hydrogen-bond O-H...O separation is slightly shortened compared with O-H...O separations in isotypic M(3)H(SeO(4))(2) crystals. In addition, it was found that the distortion of the SO(4) tetrahedra in Tl(3)H(SO(4))(2) is less than that in isotypic crystals.

Muscle adaptations and performance enhancements of soccer training for untrained men.

PubMed

Krustrup, Peter; Christensen, Jesper F; Randers, Morten B; Pedersen, Henrik; Sundstrup, Emil; Jakobsen, Markus D; Krustrup, Birgitte R; Nielsen, Jens J; Suetta, Charlotte; Nybo, Lars; Bangsbo, Jens

2010-04-01

We examined the physical demands of small-sided soccer games in untrained middle-age males and muscle adaptations and performance effects over 12 weeks of recreational soccer training in comparison with continuous running. Thirty-eight healthy subjects (20-43 years) were randomized into a soccer (SO), running (RU) and control (CO) group. Two-three weekly 1-h training sessions were performed. Muscle lactate (30.1 +/- 4.1 vs. 15.6 +/- 3.3 mmol/kg d.w.), blood lactate, blood glucose and time above 90% HR(max) (20 +/- 4% vs. 1 +/- 1%) were higher (p < 0.05) during training in SO than in RU. After 12 weeks of training, quadriceps muscle mass and mean muscle fibre area were 9 and 15% larger (p < 0.05) in SO, but unaltered in RU, and in SO, the fraction of FTx fibres was lowered (10.7 +/- 1.8 vs. 17.9 +/- 3.2%). In SO, citrate synthase activity was 10 and 14% higher (p < 0.05) after 4 and 12 weeks, but unaltered in RU. After 4 weeks VO(2max) and Yo-Yo IE2 performance were elevated (p < 0.05) to a similar extent in SO (7 and 37%) and RU (6 and 36%) but increased further (p < 0.05) from 4 to 12 weeks in SO (6 and 23%). In SO, 30-m sprint performance was improved (p < 0.05) by 0.11 +/- 0.02 s. Blood lactate during running at 11 km/h was lowered (p < 0.05) from 0 to 4 and 4 to 12 weeks (2.6 +/- 0.3 vs. 3.8 +/- 0.6 vs. 6.1 +/- 0.9 mM) and from 0 to 12 weeks in RU. No changes occurred for CO. In conclusion, recreational soccer organized as small-sided games stimulates both aerobic and anaerobic energy turnover and is an effective type of training leading to significant cardiovascular and muscular adaptations as well as performance enhancements throughout a 12-week training period.

Growth of radish and marigold following repeated exposure to nitrogen dioxide, sulfur dioxide, and ozone

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reinert, R.A.; Sanders, J.S.

Radish and marigold plants were exposed to 0.3 ppM of nitrogen dioxide (NO/sub 2/), sulfur dioxide (SO/sub 2/), and /or ozone (O/sub 3/) nine times during a 3-wk period. No interactions among NO/sub 2/, SO/sub 2/, and O/sub 3/ were detected in measurement of radish foliage and root dry weight. Treatments containing O/sub 3/ reduced radish foliage and root (hypocotyl) dry weight 356 and 531 mg/plant, respectively. Interactions among NO/sub 2/, SO/sub 2/ and O/sub 3/ occurred in shoots and roots of marigold. SO/sub 2/ alone reduced marigold shoot and root dry weight, but this effect was reversed in themore » presence of O/sub 3/. The suppressive effect of SO/sub 2/ on root weight was also reversed by NO/sub 2/. Treatments containing SO/sub 2/ reduced dry flower weight 0.17 g/plant, but effects of the pollutant interactions observed in shoots and roots were not present. 8 references, 2 tables.« less

The effect of hydrochloric acid addition to increase carbon nanotubes dispersibility as drug delivery system by covalent functionalization

NASA Astrophysics Data System (ADS)

Wulan, P. P. D. K.; Ulwani, S. H.; Wulandari, H.; Purwanto, W. W.; Mulia, K.

2018-03-01

This study is to obtain the effect of adding hydrochloric acid (HCl) to the mixture of sulfuric acid (H2SO4) and HNO3 in CNT covalent functionalization. HCl expected to increase the dispersibility of functionalized CNT by improving the dispersion time period done with H2SO4 or HNO3. Functionalization used mixture of H2SO4 and HNO3 with volume ratio of 3:1. Covalent functionalization used 0.5 grams of MWCNT ultra sonicated in 50mL HNO3 with and mixture of H2SO4 and HNO3. Additions of 200 mL HCl used variation of molarity from 1M, 2M, 3M, 4M, 5M to 6M. CNT were oxidized to form carboxylic and hydroxyl bonds on the surface that increase dispersibility of CNT. FTIR spectrums showed the existences of carboxyl and hydroxyl group on spectra of 2600-3700 cm-1 and 900-1400 cm-1. Dispersion tests, which showed functionalized CNT (f-CNT) dispersion capabilities, were done by dissolving f-CNT in water. The study resulted that 6M f-CNT (NSC6) gave the best dispersion with zeta potential value of -37.1mV. NSC6 gave the longest dispersion time which was 20 days until f-CNT settle again. SEM-EDS micrographs showed the surface structure of 6M f-CNT without significant damage and no longer contain impurities of Fe, Ni, and Cl.

Multi-band search for volcanic outgassing in the Tharsis and Syrtis Major regions on Mars

NASA Astrophysics Data System (ADS)

Khayat, Alain S. J.

We carried out the first and most comprehensive to date (2015), ground-based, semisimultaneous, multi-band and multi-species search for sulphuretted gases (SO2, H2S, OCS and SO) above the Tharsis and Syrtis volcanic regions on Mars. The submillimeter search extended between 23 November 2011 and 25 May 2014 which corresponded to Mars' mid Northern Spring and mid Northern Summer seasons (Ls = 34 - 135°). SO2, SO and H2S were targeted at their rotational transitions at 346.652 GHz, 304.078 GHz and 300.505 GHz, respectively, using the high-resolution heterodyne receiver Barney on the 10.4 m single-dish antenna of the Caltech Submillimeter Observatory (CSO), and SO2 at HARP on the 15 m James Clerk Maxwell Telescope (JCMT) at Maunakea, Hawai'i. No sulphuretted gases were detected. We infer 2sigma upper limits across the disk of the planet using the CSO of 1.1 ppb, 0.7 ppb and 1.3 ppb for SO2, SO and H2S, respectively, and 3.1 ppb on SO2 using the JCMT. The infrared search covered OCS in its combination band (nu1+nu3) at 3.42 mum (2924 cm -1), during Mars' late Northern Spring and mid Northern Summer seasons, spanning Ls= 43° and Ls= 145°, between 15 Dec. 2011 and 13 June 2014, using the high resolution infrared spectrometer CSHELL on the 3 m NASA Infrared Telescope Facility (IRTF). No absorption of atmospheric OCS has been detected, and we infer a 2sigma upper limit of 0.8 ppb on OCS. Our current limit 1.1 ppb for SO2 yields an outgassing rate of less than 55 tons/day. Compared to two terrestrial analogs, we would have been able to detect any volcanic release that is more than 4% the size of Kilauea (Hawai'i) or one twentieth the size of the Masaya volcano (Nicaragua). The mass rate of magma that is able to degas 55 tons of SO2 per day is estimated as 37 kilotons of magma per day, or 12,000 m3 per day (0.14 m3/s). The non-detection of any of the sulfur compounds in the atmosphere of Mars provides limits to the level of current volcanic activity in the crust of Mars.

Field performance of a semi-continuous monitor for ambient PM2.5 water-soluble inorganic ions and gases at a suburban site

NASA Astrophysics Data System (ADS)

Young, Li-Hao; Li, Chiao-Hsin; Lin, Ming-Yeng; Hwang, Bing-Fang; Hsu, Hui-Tsung; Chen, Yu-Cheng; Jung, Chau-Ren; Chen, Kuan-Chi; Cheng, Dung-Hung; Wang, Ven-Shing; Chiang, Hung-Che; Tsai, Perng-Jy

2016-11-01

To reduce sampling artifacts and to improve time-resolved measurements of inorganic aerosol system, a recently commercialized semi-continuous In-situ Gas and Aerosol Composition (IGAC) monitoring system was evaluated against a reference annular denuder system (ADS; denuder/two-stage filter pack) at a suburban site over a year, during which the average PM2.5 was 37.0 ± 24.8 μg/m3. A suite of eight ions SO42-, NO3-, Cl-, NH4+, Na+, K+, Ca2+ and Mg2+ and two gases SO2 and NH3 were the target species. In comparison to the reference ADS method, the IGAC performed well in measuring the major ions SO42-, NO3- and NH4+, and the SO2. For those species, the linear slopes, intercepts and R2 values between the two methods all passed the performance evaluation criteria outlined by earlier similar studies. The performance of IGAC on Cl-, Na+, K+ and NH3 was marginally acceptable, whereas Ca2+ and Mg2+ could not be properly evaluated due to the low concentrations (<0.2 μg/m3) and hence inadequate amount of sample size. The ionic balance of the hourly IGAC samples averaged very close to unity, as did the daily ADS samples, though the former was considerably more variable than the latter. The overall performance of the IGAC has been shown to be comparable to other similar monitors and its improvements are discussed.

Rain water chemistry in Ankara, Turkey

NASA Astrophysics Data System (ADS)

Tuncel, Semra G.; Ungör, Sevgi

Samples of rain water were collected in Ankara for the period between September 1989 and May 1990, by using wet-only sampler. Concentrations of major cations (H +, Na + K + Ca 2+ and NH 4+) and major anions (Cl -, NO 3- and SO 42-) were determined for the first time in Turkey. The rain water was not acidic owing to high concentrations of alkaline soil particles in the atmosphere. However, the concentrations of acid forming ions, such as SO 4- and N03, were higher than the concentrations expected in a typical urban atmosphere. Most of the SO 4- in rain water was in the form of CaSO 4. Rain-aerosol coupling were examined by simultaneous sampling of aerosols with rain. The ions most efficiently scavenged from the atmosphere were found to be SO 42- and Ca 2+.

Impact of intensive agricultural practices on drinking water quality in the Evros region (NE Greece) by GIS analysis.

PubMed

Nikolaidis, C; Mandalos, P; Vantarakis, A

2008-08-01

Chemical fertilizers are used extensively in modern agriculture, in order to improve yield and productivity of agricultural products. However, nutrient leaching from agricultural soil into groundwater resources poses a major environmental and public health concern. The Evros region is one of the largest agricultural areas in Northern Greece, extending over 1.5 million acres of cultivated land. Many of its drinking water resources are of groundwater origin and lie within agricultural areas. In order to assess the impact of agricultural fertilizers on drinking water quality in this region, tap-water samples from 64 different locations were collected and analyzed for the presence of nitrates (NO(3)(-)), nitrites (NO(2)(-)), ammonium (NH(4)(+)), sulfate (SO(4)(-2)) and phosphate (PO(4)(-3)). These chemicals were selected based on the information that ammonium nitrate, ammonium sulfate and inorganic phosphate were the primary fertilizers used in local crop production. NO(3)(-), SO(4)(-2) and PO(4)(-3) levels exceeding accepted values were recorded in 6.25, 4.70 and 9.38% of all sampling points, respectively. NO(2)(-) and NH(4)(+) concentrations, on the other hand, were inside the permitted range. The data generated were introduced into a geographic information system (GIS) program for computer analysis and projection maps representing afflicted areas were created. Our results indicate a profound geographic correlation in the surface distribution of primary contaminants in areas of intensified agricultural production. Thus, drinking water pollution in these areas can be attributed to excessive fertilizer use from agricultural sources.

Fireside Corrosion Behaviors of Super304H and HR3C in Coal Ash/Gas Environment with Different SO2 Contents at 650 °C

NASA Astrophysics Data System (ADS)

Lu, Jintao; Yang, Zhen; Li, Yan; Huang, Jinyang; Zhou, Yongli; Zhao, Xinbao; Yuan, Yong

2018-05-01

The corrosion behaviors of Super304H and HR3C used for USC boiler applications were investigated in simulated coal ash/gas environments with 0.1 and 1.5% of SO2 at 650 °C for 500 h. The results indicated that the increase in SO2 accelerated the corrosion rate and the spalling tendency of the corrosion layer in both tested alloys. Fe2O3, Cr2O3 and FeCr2O4 main peaks were revealed by XRD on Super304H, but on HR3C only the Cr2O3 peak showed a high intensity. The SO2 content did not affect the corrosion product composition of any of the alloys, but accelerated the inner sulfidation and the spallation on Super304H. No obvious internal sulfidation was observed on HR3C in either SO2 content. Based on the experimental results, the alloy corrosion mechanism and the influence of sulfur content on the corrosion process were discussed.

Thermal decomposition behavior of the rare-earth ammonium sulfate R{sub 2}(SO{sub 4}){sub 3}.(NH{sub 4}){sub 2}SO{sub 4}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nagai, Tsukasa; Japan Society for the Promotion of Science, 1-8 Chiyoda-ku, Tokyo 102-8472; Tamura, Shinji

2010-07-15

Rare-earth ammonium sulfate octahydrates of R{sub 2}(SO{sub 4}){sub 3}.(NH{sub 4}){sub 2}SO{sub 4}.8H{sub 2}O (R=Pr, Nd, Sm, and Eu) were synthesized by a wet process, and the stable temperature region for the anhydrous R{sub 2}(SO{sub 4}){sub 3}.(NH{sub 4}){sub 2}SO{sub 4} form was clarified by thermogravimetry/differential thermal analysis, infrared, Raman, and electrical conductivity measurements. Detailed characterization of these double salts demonstrated that the thermal stability of anhydrous R{sub 2}(SO{sub 4}){sub 3}.(NH{sub 4}){sub 2}SO{sub 4} is different between the Pr, Nd salts and the Sm, Eu salts, and the thermal decomposition behavior of these salts was quite different from the previous reports. -more » Graphical abstract: Stable temperature range of anhydrous rare-earth ammonium sulfate R{sub 2}(SO{sub 4}){sub 3}.(NH{sub 4}){sub 2}SO{sub 4} was clarified by thermogravimetry/differential thermal analysis, infrared, Raman, and electrical conductivity measurements. Since the previous reports were based only on thermal analysis, the present work has more accurately determined the exact thermal stability of rare-earth ammonium sulfate solids.« less

Identification of newly isolated Talaromyces pinophilus and statistical optimization of β-glucosidase production under solid-state fermentation.

PubMed

El-Naggar, Noura El-Ahmady; Haroun, S A; Oweis, Eman A; Sherief, A A

2015-01-01

Fungi able to degrade agriculture wastes were isolated from different soil samples, rice straw, and compost; these isolates were screened for their ability to produce β-glucosidase. The most active fungal isolate was identified as Talaromyces pinophilus strain EMOO 13-3. The Plackett-Burman design is used for identifying the significant variables that influence β-glucosidase production under solid-state fermentation. Fifteen variables were examined for their significances on the production of β-glucosidase in 20 experimental runs. Among the variables screened, moisture content, Tween 80, and (NH4)2SO4 had significant effects on β-glucosidase production with confidence levels above 90% (p < 0.1). The optimal levels of these variables were further optimized using Box-Behnken statical design. As a result, the maximal β-glucosidase activity is 3648.519 U g(-1), which is achieved at the following fermentation conditions: substrate amount 0.5 (g/250 mL flask), NaNO3 0.5 (%), KH2PO4 0.3 (%), KCl 0.02 (%), MgSO4 · 7H2O 0.01 (%), CaCl2 0.01 (%), yeast extract 0.07 (%), FeSO4 · 7H2O 0.0002 (%), Tween 80 0.02 (%), (NH4)2SO4 0.3 (%), pH 6.5, temperature 25°C, moisture content 1 (mL/g dry substrate), inoculum size 0.5 (mL/g dry substrate), and incubation period 5 days.

Quality of fresh and stored carrots depending on iodine and nitrogen fertilization.

PubMed

Smoleń, Sylwester; Sady, Włodzimierz; Ledwożyw-Smoleń, Iwona; Strzetelski, Piotr; Liszka-Skoczylas, Marta; Rożek, Stanisław

2014-09-15

Iodine is an important mineral nutrient essential for a proper functioning of human and animal organism. Despite current programmes of iodine prophylaxis (mainly based on salt iodization) approximately 30-38% of human population has insufficient iodine intake. Crop plants can become an efficient vector of this element in the food chain. Iodine is not a nutrient for plants. For that reason, in addition to determining the possibility of increasing iodine content in crop plant it is necessary to describe its impact on yield quality. The aim of the study was to analyze the influence of soil fertilization with iodine and nitrogen on the quality of carrot roots and its storage ability. In 2008-2010 the field study with carrot cv. 'Kazan F1' was conducted. A differential soil fertilization with iodine (in the form of I(-) or IO3(-)) and nitrogen (as NO3(-) or NH4(+)) was applied in the experiment: (1) control without N and I, (2) KI application without N, (3) KIO3 application without N, (4) KI+Ca(NO3)2, (5) KIO3+Ca(NO3)2, (6) KI+(NH4)2SO4 and (7) KIO3+(NH4)2SO4. The experiment was arranged in a split-plot design. Iodine (in both forms) was applied pre-sowing in a dose of 2 kg I ha(-1). Nitrogen in the form of Ca(NO3)2 and (NH4)2SO4 was introduced pre-sowing and as a top dressing, each dose of 100 kg N ha(-1). A diverse, statistically significant influence of tested factors on the activity of free radical-scavenging (DPPH) and the content of: dry matter, glucose, fructose, sucrose, total soluble sugars, soluble solids - Brix %, phenolic compounds, phenylpropanoids, flavonols, anthocyanins and carotenoids was noted in carrot roots directly after the harvest as well as at the end of four-month storage. Iodine applied with relatively high doses of nitrogen decreased the quality of fresh carrot. After storage, opposite relations were noted for tested combinations (with I and N application) with respect to carrot quality when compared to results obtained after the harvest. The lowest storage ability was found for carrot treated with KI without N. Obtained results directly suggest the need for developing individual agronomic rules for iodine biofortification of carrot for: (a) consumption and/or processing directly after the harvest and (b) long-term storage. Copyright © 2014 Elsevier Ltd. All rights reserved.

The contribution of residential coal combustion to atmospheric PM2. 5 in northern China during winter

NASA Astrophysics Data System (ADS)

Liu, Pengfei; Zhang, Chenglong; Xue, Chaoyang; Mu, Yujing; Liu, Junfeng; Zhang, Yuanyuan; Tian, Di; Ye, Can; Zhang, Hongxing; Guan, Jian

2017-09-01

A vast area in northern China, especially during wintertime, is currently suffering from severe haze events due to the high levels of atmospheric PM2. 5. To recognize the reasons for the high levels of PM2. 5, daily samples of PM2. 5 were simultaneously collected at the four sampling sites of Beijing city (BJ), Baoding city (BD), Wangdu county (WD) and Dongbaituo (DBT) during the winter and spring of 2014-2015. The concentrations of the typical water-soluble ions (WSIs, such as Cl-, NO3-, SO42- and NH4+) at DBT were found to be remarkably higher than those at BJ in the two winters, but almost the same as those at BJ in the two springs. The evidently greater concentrations of OC, EC and secondary inorganic ions (NO3-, SO42-, NH4+ and Cl-) at DBT than at WD, BD and BJ during the winter of 2015 indicated that the pollutants in the rural area were not due to transportation from neighbouring cities but dominated by local emissions. As the distinct source of atmospheric OC and EC in the rural area, the residential coal combustion also made a contribution to secondary inorganic ions through the emissions of their precursors (NOx, SO2, NH3 and HCl) as well as heterogeneous or multiphase reactions on the surface of OC and EC. The average mass proportions of OC, EC, NO3- and SO42- at BD and WD were found to be very close to those at DBT, but were evidently different from those at BJ, implying that the pollutants in the cities of WD and BD, which are fully surrounded by the countryside, were strongly affected by the residential coal combustion. The OC / EC ratios at the four sampling sites were almost the same value (4.8) when the concentrations of PM2. 5 were greater than 150 µg m-3, suggesting that the residential coal combustion could also make a dominant contribution to atmospheric PM2. 5 at BJ during the severe pollution period when the air parcels were usually from southwest-south regions, where a high density of farmers reside. The evident increase in the number of the species involved in significant correlations (p < 0. 05) from the countryside to the cities further confirmed that residential coal combustion was the dominant source of key species in the rural area. However, the complex sources including local emissions and regional transportation were responsible for the atmospheric species in the cities. Strong correlations among OC, EC, Cl-, NO3- and NH4+ were found at the four sampling sites but only a strong correlation was found between OC (or EC) and SO42- at BJ, implying that the formation rate of SO42- via heterogeneous or multiphase reactions might be relatively slower than those of NO3-, NH4+ and Cl-. Based on the chemical mass closure (CMC) method, the contributions of the primary particle emission from residential coal combustion to atmospheric PM2. 5 at BJ, BD, WD and DBT were estimated to be 32, 49, 43 and 58 %, respectively.

Variation of Ambient Ammonia Pollution in Relation With PM2.5 Characteristics in Winter of Delhi, India

NASA Astrophysics Data System (ADS)

S., Sr.; Saxena, M., , Dr; Mandal, T. K., , Dr; Kotnala, R. K.; Sharma, S. K., , Dr

2017-12-01

Ambient ammonia, SO2 and NOx are primary precursor gases for the formation of particulate matter (PM2.5) which result in photochemical smog and haze formation specifically in winter season. The ambient ammonia, other trace gases and fine particles were monitored in winter season from Jan 2013 to Dec 2015 at CSIR-NPL, Delhi. The average mixing ratios of ambient NH3, NO, NO2 and SO2 over the entire period of winter season were recorded as 25.3±4.6 (ppb), 21.4±7.2 (ppb), 20.8±5.9 (ppb) and 1.9±0.5 (ppm), respectively. The NH4+ and other ionic species in PM2.5 were also simultaneously observed at the the study site to see the transformation of NH3 and NH4+. The results indicated that the concentration level of NH3 and NH4+/NH3 ratios grew simultaneously with the increase of PM2.5 levels. NH3 enhanced the formation of ammonium sulphate and ammonium nitrate and exert a significant impact on ion chemistry of PM2.5. In the wintertime atmosphere of urban Delhi, NH3 was sufficient in fully neutralizing the fine particulates. The important role of ammonia is recognized in increasing PM2.5 mass concentration as it help in formation of ammonium aerosol due to reaction with acid gases. Keywords: Air quality, Ammonia, Trace Gases, Particulates

The use of multicomponent statistical analysis in hydrogeological environmental research.

PubMed

Lambrakis, Nicolaos; Antonakos, Andreas; Panagopoulos, George

2004-04-01

The present article examines the possibilities of investigating NO(3)(-) spread in aquifers by applying multicomponent statistical methods (factor, cluster and discriminant analysis) on hydrogeological, hydrochemical, and environmental parameters. A 4-R-Mode factor model determined from the analysis showed its useful role in investigating hydrogeological parameters affecting NO(3)(-) concentration, such as its dilution by upcoming groundwater of the recharge areas. The relationship between NO(3)(-) concentration and agricultural activities can be determined sufficiently by the first factor which relies on NO(3)(-) and SO(4)(2-) of the same origin-that of agricultural fertilizers. The other three factors of R-Mode analysis are not connected directly to the NO(3)(-) problem. They do however, by extracting the role of the unsaturated zone, show an interesting relationship between organic matter content, thickness and saturated hydraulic conductivity. The application of Hirerarchical Cluster Analysis, based on all possible combinations of classification method, showed two main groups of samples. The first group comprises samples from the edges and the second from the central part of the study area. By the application of Discriminant Analysis it was shown that NO(3)(-) and SO(4)(2-) ions are the most significant variables in the discriminant function. Therefore, the first group is considered to comprise all samples from areas not influenced by fertilizers lying on the edges of contaminating activities such as crop cultivation, while the second comprises all the other samples.

Structural trends for celestite (SrSO[subscript 4]), anglesite (PbSO[subscript 4]), and barite (BaSO[subscript 4]): Confirmation of expected variations within the SO[subscript 4] groups

DOE Office of Scientific and Technical Information (OSTI.GOV)

Antao, Sytle M.

2012-05-10

The crystal structures of the isostructural orthorhombic sulfates celestite (SrSO{sub 4}), anglesite (PbSO{sub 4}), and barite (BaSO{sub 4}) were refined by Rietveld methods using synchrotron high-resolution powder X-ray diffraction (HRPXRD) data. Their structural model was refined in space group Pbnm. The unit-cell parameters are a = 6.87032(3), b = 8.36030(5), c = 5.34732(1) {angstrom}, and V = 307.139(3) {angstrom}{sup 3} for SrSO{sub 4}; a = 6.95802(1), b = 8.48024(3), c = 5.39754(1) {angstrom}, and V = 318.486(1) {angstrom}{sup 3} for PbSO{sub 4}; and a = 7.15505(1), b = 8.88101(3), c = 5.45447(1) {angstrom}, and V = 346.599(1) {angstrom}{sup 3} formore » BaSO{sub 4}. The average [12] distances are 2.827(1), 2.865(1), and 2.953(1) {angstrom} for SrSO{sub 4}, PbSO{sub 4}, and BaSO{sub 4}, respectively, and their corresponding average [4] distances are 1.480(1), 1.477(3), and 1.471(1) {angstrom}. The geometrical features of the SO{sub 4} and MO{sub 12} polyhedra become more symmetrical from SrSO{sub 4} to BaSO{sub 4}. Across the series, the a, b, and c parameters vary non-linearly with increasing V. The radii of the M{sup 2+} cations, rM, [12], and [4] distances vary linearly with V. These structural trends arise from the effective size of the M{sup 2+} cation (rM: Sr < Pb < Ba) that is coordinated to 12 O atoms.« less

Evaluation of the new capture vapourizer for aerosol mass spectrometers (AMS) through laboratory studies of inorganic species

DOE PAGES

Hu, Weiwei; Campuzano-Jost, Pedro; Day, Douglas A.; ...

2017-08-15

Aerosol mass spectrometers (AMSs) and Aerosol Chemical Speciation Monitors (ACSMs) commercialized by Aerodyne are widely used to measure the non-refractory species in submicron particles. With the standard vapourizer (SV) that is installed in all commercial instruments to date, the quantification of ambient aerosol mass concentration requires the use of the collection efficiency (CE) to correct for the loss of particles due to bounce. A new capture vapourizer (CV) has been designed to reduce the need for a bounce-related CE correction. Two high-resolution AMS instruments, one with a SV and one with a CV, were operated side by side in themore » laboratory. Four standard species, NH 4NO 3, NaNO 3, (NH 4) 2SO 4 and NH 4Cl, which typically constitute the majority of the mass of ambient submicron inorganic species, are studied. The effect of vapourizer temperature ( T v ∼ 200–800 °C) on the detected fragments, CE and size distributions are investigated. A T v of 500–550 °C for the CV is recommended. In the CV, CE was identical (around unity) for more volatile species (e.g. NH 4NO 3) and comparable to or higher than the SV for less-volatile species (e.g. (NH 4) 2SO 4), demonstrating an improvement in CE for laboratory inorganic species in the CV. The detected relative intensities of fragments of NO 3 and SO 4 species observed with the CV are different from those observed with the SV, and are consistent with additional thermal decomposition arising from the increased residence time and multiple collisions. Increased residence times with the CV also lead to broader particle size distribution measurements than with the SV. A method for estimating whether pure species will be detected in AMS sizing mode is proposed. Production of CO 2(g) from sampled nitrate on the vapourizer surface, which has been reported for the SV, is negligible for the CV for NH 4NO 3 and comparable to the SV for NaNO 3. . We observe an extremely consistent fragmentation for ammonium compared to very large changes for the associated anions. Together with other evidence, this indicates that it is unlikely that a major fraction of inorganic species vapourizes as intact salts in the AMS.« less

Evaluation of the new capture vapourizer for aerosol mass spectrometers (AMS) through laboratory studies of inorganic species

NASA Astrophysics Data System (ADS)

Hu, Weiwei; Campuzano-Jost, Pedro; Day, Douglas A.; Croteau, Philip; Canagaratna, Manjula R.; Jayne, John T.; Worsnop, Douglas R.; Jimenez, Jose L.

2017-08-01

Aerosol mass spectrometers (AMSs) and Aerosol Chemical Speciation Monitors (ACSMs) commercialized by Aerodyne are widely used to measure the non-refractory species in submicron particles. With the standard vapourizer (SV) that is installed in all commercial instruments to date, the quantification of ambient aerosol mass concentration requires the use of the collection efficiency (CE) to correct for the loss of particles due to bounce. A new capture vapourizer (CV) has been designed to reduce the need for a bounce-related CE correction. Two high-resolution AMS instruments, one with a SV and one with a CV, were operated side by side in the laboratory. Four standard species, NH4NO3, NaNO3, (NH4)2SO4 and NH4Cl, which typically constitute the majority of the mass of ambient submicron inorganic species, are studied. The effect of vapourizer temperature (Tv ˜ 200-800 °C) on the detected fragments, CE and size distributions are investigated. A Tv of 500-550 °C for the CV is recommended. In the CV, CE was identical (around unity) for more volatile species (e.g. NH4NO3) and comparable to or higher than the SV for less-volatile species (e.g. (NH4)2SO4), demonstrating an improvement in CE for laboratory inorganic species in the CV. The detected relative intensities of fragments of NO3 and SO4 species observed with the CV are different from those observed with the SV, and are consistent with additional thermal decomposition arising from the increased residence time and multiple collisions. Increased residence times with the CV also lead to broader particle size distribution measurements than with the SV. A method for estimating whether pure species will be detected in AMS sizing mode is proposed. Production of CO2(g) from sampled nitrate on the vapourizer surface, which has been reported for the SV, is negligible for the CV for NH4NO3 and comparable to the SV for NaNO3. . We observe an extremely consistent fragmentation for ammonium compared to very large changes for the associated anions. Together with other evidence, this indicates that it is unlikely that a major fraction of inorganic species vapourizes as intact salts in the AMS.

Evaluation of the new capture vapourizer for aerosol mass spectrometers (AMS) through laboratory studies of inorganic species

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hu, Weiwei; Campuzano-Jost, Pedro; Day, Douglas A.

Aerosol mass spectrometers (AMSs) and Aerosol Chemical Speciation Monitors (ACSMs) commercialized by Aerodyne are widely used to measure the non-refractory species in submicron particles. With the standard vapourizer (SV) that is installed in all commercial instruments to date, the quantification of ambient aerosol mass concentration requires the use of the collection efficiency (CE) to correct for the loss of particles due to bounce. A new capture vapourizer (CV) has been designed to reduce the need for a bounce-related CE correction. Two high-resolution AMS instruments, one with a SV and one with a CV, were operated side by side in themore » laboratory. Four standard species, NH 4NO 3, NaNO 3, (NH 4) 2SO 4 and NH 4Cl, which typically constitute the majority of the mass of ambient submicron inorganic species, are studied. The effect of vapourizer temperature ( T v ∼ 200–800 °C) on the detected fragments, CE and size distributions are investigated. A T v of 500–550 °C for the CV is recommended. In the CV, CE was identical (around unity) for more volatile species (e.g. NH 4NO 3) and comparable to or higher than the SV for less-volatile species (e.g. (NH 4) 2SO 4), demonstrating an improvement in CE for laboratory inorganic species in the CV. The detected relative intensities of fragments of NO 3 and SO 4 species observed with the CV are different from those observed with the SV, and are consistent with additional thermal decomposition arising from the increased residence time and multiple collisions. Increased residence times with the CV also lead to broader particle size distribution measurements than with the SV. A method for estimating whether pure species will be detected in AMS sizing mode is proposed. Production of CO 2(g) from sampled nitrate on the vapourizer surface, which has been reported for the SV, is negligible for the CV for NH 4NO 3 and comparable to the SV for NaNO 3. . We observe an extremely consistent fragmentation for ammonium compared to very large changes for the associated anions. Together with other evidence, this indicates that it is unlikely that a major fraction of inorganic species vapourizes as intact salts in the AMS.« less

Long-term effects of changing atmospheric pollution on throughfall, bulk deposition and streamwaters in a Mediterranean forest.

PubMed

Aguillaume, Laura; Rodrigo, Anselm; Avila, Anna

2016-02-15

The abatement programs implanted in Europe to reduce SO2, NO2 and NH3 emissions are here evaluated by analyzing the relationships between emissions in Spain and neighboring countries and atmospheric deposition in a Mediterranean forest in the Montseny mountains (NE Spain) for the last 3decades. A canopy budget model was applied to throughfall data measured during a period of high emissions (1995-1996) and a period of lower emissions (2011-2013) to estimate the changes in dry deposition over this time span. Emissions of SO2 in Spain strongly decreased (77%) and that was reflected in reductions for nssSO4(2-) in precipitation (65% for concentrations and 62% for SO4(2)-S deposition). A lower decline was found for dry deposition (29%). Spanish NO2 emissions increased from 1980 to 1991, remained constant until 2005, and decreased thereafter, a pattern that was paralleled by NO3(-) concentrations in bulk precipitation at Montseny. This pattern seems to be related to a higher share of renewable energies in electricity generation in Spain in recent years. However, dry deposition increased markedly between 1995 and 2012, from 1.3 to 6.7 kg ha(-1) year(-)(1). Differences in meteorology between periods may have had a role, since the recent period was drier thus probably favoring dry deposition. Spanish NH3 emissions increased by 13% between 1980 and 2012 in Spain but NH4(+) concentrations in precipitation and NH4(+)-N deposition showed a decreasing trend (15% reduction) at Montseny, probably linked to the reduction ammonium sulfate and nitrate aerosols to be scavenged by rainfall. NH4(+)-N dry deposition was similar between the compared periods. The N load at Montseny (15-17 kg ha(-1)y ear(-1)) was within the critical load range proposed for Mediterranean sclerophyllous forests (15-17.5 kg ha(-1) year(-1)). The onset of N saturation is suggested by the observed increasing N export in streamwaters. Copyright © 2015 Elsevier B.V. All rights reserved.

Adsorption of SO2 and NO from incineration flue gas onto activated carbon fibers.

PubMed

Liu, Zhen-Shu

2008-11-01

Activated carbon fibers (ACFs) were used to remove SO2 and NO from incineration flue gas. Three types of ACFs in their origin state and after pretreatment with HNO3, NaOH, and KOH were investigated. The removal efficiencies of SO2 and NO were determined experimentally at defined SO2 and NO concentrations and at temperatures of 150, 200 and 260 degrees C. Experimental results indicated that the removal efficiencies of SO2 and NO using the original ACFs were < 56% and < 27%, respectively. All ACFs modified with HNO3, NaOH, and KOH solution could increase the removal efficiencies of SO(2) and NO. The mesopore volumes and functional groups of ACFs are important in determining the removal of SO2 and NO. When the mesopore volumes of the ACFs are insufficient for removing SO2 and NO, the functional groups on the ACFs are not important in determining the removal of SO2 and NO. On the contrary, the effects of the functional groups on the removal of SO2 and NO are more important than the mesopore volumes as the amount of mesopores on the ACFs is sufficient to remove SO2 and NO. Moreover, the removal efficiencies of SO2 and NO were greatest at 200 degrees C. When the inlet concentration of SO2 increased to 600 ppm, the removal efficiency of SO2 increased slightly and the removal efficiency of NO decreased.

Effects of lead mineralogy on soil washing enhanced by ferric salts as extracting and oxidizing agents.

PubMed

Yoo, Jong-Chan; Park, Sang-Min; Yoon, Geun-Seok; Tsang, Daniel C W; Baek, Kitae

2017-10-01

In this study, we evaluated the feasibility of using ferric salts including FeCl 3 and Fe(NO 3 ) 3 as extracting and oxidizing agents for a soil washing process to remediate Pb-contaminated soils. We treated various Pb minerals including PbO, PbCO 3 , Pb 3 (CO 3 ) 2 (OH) 2 , PbSO 4 , PbS, and Pb 5 (PO 4 ) 3 (OH) using ferric salts, and compared our results with those obtained using common washing agents of HCl, HNO 3 , disodium-ethylenediaminetetra-acetic acid (Na 2 -EDTA), and citric acid. The use of 50 mM Fe(NO 3 ) 3 extracted significantly more Pb (above 96% extraction) from Pb minerals except PbSO 4 (below 55% extraction) compared to the other washing agents. In contrast, washing processes using FeCl 3 and HCl were not effective for extraction from Pb minerals because of PbCl 2 precipitation. Yet, the newly formed PbCl 2 could be dissolved by subsequent wash with distilled water under acidic conditions. When applying our washing method to remediate field-contaminated soil from a shooting range that had high concentrations of Pb 3 (CO 3 ) 2 (OH) 2 and PbCO 3 , we extracted more Pb (approximately 99% extraction) from the soil using 100 mM Fe(NO 3 ) 3 than other washing agents at the same process conditions. Our results show that ferric salts can be alternative washing agents for Pb-contaminated soils in view of their extracting and oxidizing abilities. Copyright © 2017 Elsevier Ltd. All rights reserved.

EnviroAtlas - Atmospheric Nitrogen Deposition by 12-digit HUC for the Conterminous United States (2002)

EPA Pesticide Factsheets

This EnviroAtlas dataset includes annual nitrogen and sulfur deposition within each 12-digit HUC subwatershed for the year 2002. Values are provided for total oxidized nitrogen (HNO3, NO, NO2, N2O5, NH3, HONO, PAN, organic nitrogen, and particulate NO3), oxidized nitrogen wet deposition, oxidized nitrogen dry deposition, total reduced nitrogen (NH3 and particulate NH4), reduced nitrogen dry deposition, reduced nitrogen wet deposition, total dry nitrogen deposition, total wet nitrogen deposition, total nitrogen deposition (wet+dry), total sulfur (SO2 + particulate SO4) dry deposition, total sulfur wet deposition, and total sulfur deposition. The dataset is based on output from the Community Multiscale Air Quality modeling system (CMAQ) v5.0.2 run using the bidirectional flux option for the 12-km grid size for the US, Canada, and Mexico. The CMAQ output has been post-processed to adjust the wet deposition for errors in the location and amount of precipitation and for regional biases in the TNO3 (HNO3 + NO3), NHx (NH4 + NH3), and sulfate wet deposition. Model predicted values of dry deposition were not adjusted. This dataset was produced by the US EPA to support research and online mapping activities related to EnviroAtlas. EnviroAtlas (https://www.epa.gov/enviroatlas) allows the user to interact with a web-based, easy-to-use, mapping application to view and analyze multiple ecosystem services for the contiguous United States. The dataset is available as downloadab

Identification of sources and behavior of agricultural contaminants in groundwater using nitorgen and sulfur isootope in Haean basin, Korea

NASA Astrophysics Data System (ADS)

Kaown, Dugin; Kim, Heejung; Mayer, Bernard; Hyun, Yunjung; Lee, Jin-Yong; Lee, Kang-Kun

2013-04-01

The Haean basin shows a bowl-shaped topographic feature and the drainage system shows a dendritic pattern. The study area is consisted of forests (58.0%), vegetable fields (27.6%), rice paddy fields (11.4%) and fruit fields (0.5%). Most of residents in the study area practice agriculture and paddy rice and vegetables (Chinese radish) are the typical crops grown. The concentration of nitrate in groundwater showed 0.8 ~ 67.3 mg/L in June, 2012 and 2.0 ~ 65.7 mg/L in September, 2012. Hydrogeochemical values and stable isotope ratios of dissolved nitrate and sulfate in groundwater were used to identify contamination sources and transformation processes in shallow groundwater. The δ15N-NO3- values in the study area ranged between +5.2 and +16.9‰ in June and between +4.4 and +13.0‰ in September. The sulfate concentration in groundwater samples obtained from the study area varied from 0.8 to 16.5 mg/L in June and 0 to 19.7 mg/L in September. δ34S-SO42- values ranged from +2.9 to +11.7‰ in June and +1.6 to +8.2‰ in September. The values of δ15N-NO3- and δ34S-SO42- in September were slightly decreased than those of values in June. The chemical composition of groundwater in vegetable and fruit fields showed slightly lower values of δ34S-SO42- and δ15N-NO3- indicated that a mixture of synthetic and organic fertilizers is responsible for groundwater contamination with agro-chemicals. Most groundwater from forests and paddy fields showed slightly higher values of δ15N-NO3- suggested that organic fertilizer is introduced into subsurface.

Role of Inherent Inorganic Constituents in SO2 Sorption Ability of Biochars Derived from Three Biomass Wastes.

PubMed

Xu, Xiaoyun; Huang, Daxuan; Zhao, Ling; Kan, Yue; Cao, Xinde

2016-12-06

Biochar is rich in both organic carbon and inorganic components. Extensive work has attributed the high sorption ability of biochar to the pore structure and surface chemical property related to its organic carbon fraction. In this study, three biochars derived from dairy manure (DM-biochar), sewage sludge (SS-biochar), and rice husk (RH-biochar), respectively, were evaluated for their SO 2 sorption behavior and the underlying mechanisms, especially the role of inherent inorganic constituents. The sorption capacities of SO 2 by the three biochars were 8.87-15.9 mg g -1 . With the moisture content increasing from 0% to 50%, the sorption capacities increased by up to about 3 times, mainly due to the formation of alkaline water membrane on the biochar surface which could promote the sorption and transformation of acidic SO 2 . DM- and SS-biochar containing larger mineral constituents showed higher sorption capacity for SO 2 than RH-biochar containing less mineral components. CaCO 3 and Ca 3 (PO 4 ) 2 in DM-biochar induced sorbed SO 2 transformation into K 2 Ca(SO 4 ) 2 ·H 2 O and CaSO 4 ·2H 2 O, while the sorbed SO 2 was converted to Fe 2 (SO 4 ) 3 ·H 2 SO 4 ·2H 2 O, CaSO 4 ·2H 2 O, and Ca 3 (SO 3 ) 2 SO 4 ·12H 2 O in SS-biochar. For RH-biochar, K 3 H(SO 4 ) 2 might exist in the exhausted samples. Overall, the chemical transformation of SO 2 induced by biochar inherent mineral components occupied 44.6%-85.5% of the total SO 2 sorption. The results obtained from this study demonstrated that biochar as a unique carbonaceous material could distinctly be a promising sorbent for acidic SO 2 removal in which the inorganic components played an important role in the SO 2 sorption and transformation.

Feasibility of coupling a thermal/optical carbon analyzer to a quadrupole mass spectrometer for enhanced PM2.5 speciation.

PubMed

Riggio, Gustavo M; Chow, Judith C; Cropper, Paul M; Wang, Xiaoliang; Yatavelli, Reddy L N; Yang, Xufei; Watson, John G

2018-05-01

A thermal/optical carbon analyzer (TOA), normally used for quantification of organic carbon (OC) and elemental carbon (EC) in PM 2.5 (fine particulate matter) speciation networks, was adapted to direct thermally evolved gases to an electron impact quadrupole mass spectrometer (QMS), creating a TOA-QMS. This approach produces spectra similar to those obtained by the Aerodyne aerosol mass spectrometer (AMS), but the ratios of the mass to charge (m/z) signals differ and must be remeasured using laboratory-generated standards. Linear relationships are found between TOA-QMS signals and ammonium (NH 4 + ), nitrate (NO 3 - ), and sulfate (SO 4 2- ) standards. For ambient samples, however, positive deviations are found for SO 4 2- , compensated by negative deviations for NO 3 - , at higher concentrations. This indicates the utility of mixed-compound standards for calibration or separate calibration curves for low and high ion concentrations. The sum of the QMS signals across all m/z after removal of the NH 4 + , NO 3 - , and SO 4 2- signals was highly correlated with the carbon content of oxalic acid (C₂H₂O₄) standards. For ambient samples, the OC derived from the TOA-QMS method was the same as the OC derived from the standard IMPROVE_A TOA method. This method has the potential to reduce complexity and costs for speciation networks, especially for highly polluted urban areas such as those in Asia and Africa. Ammonium, nitrate, and sulfate can be quantified by the same thermal evolution analysis applied to organic and elemental carbon. This holds the potential to replace multiple parallel filter samples and separate laboratory analyses with a single filter and a single analysis to account for a large portion of the PM 2.5 mass concentration.

Subsonic Wind Tunnel Testing Handbook

DTIC Science & Technology

1991-05-01

the tissue shows no stains . Avoid letting the solvent evaporate completely before it is wiped. 4. Apply an Alodine solution to the surface with a swab...14 4 5.158 1 40 4.54 3.930 ] A191 &so .452 -- 9 3,.354 690" 2�. - l4 in. 14. . 7" 47 261 3,.1 .212,o 1157• 3 6 12% 4f i bI 3 w 1-11 711ll7ri 5 1

Ambient air pollution exposure and respiratory, cardiovascular and cerebrovascular mortality in Cape Town, South Africa: 2001–2006.

PubMed

Wichmann, Janine; Voyi, Kuku

2012-11-05

Little evidence is available on the strength of the association between ambient air pollution exposure and health effects in developing countries such as South Africa. The association between the 24-h average ambient PM(10), SO(2) and NO(2) levels and daily respiratory (RD), cardiovascular (CVD) and cerebrovascular (CBD) mortality in Cape Town (2001-2006) was investigated with a case-crossover design. For models that included entire year data, an inter-quartile range (IQR) increase in PM(10) (12 mg/m3) and NO(2) (12 mg/m3) significantly increased CBD mortality by 4% and 8%, respectively. A significant increase of 3% in CVD mortality was observed per IQR increase in NO(2) and SO(2) (8 mg/m3). In the warm period, PM(10) was significantly associated with RD and CVD mortality. NO(2) had significant associations with CBD, RD and CVD mortality, whilst SO(2) was associated with CVD mortality. None of the pollutants were associated with any of the three outcomes in the cold period. Susceptible groups depended on the cause-specific mortality and air pollutant. There is significant RD, CVD and CBD mortality risk associated with ambient air pollution exposure in South Africa, higher than reported in developed countries.

Improved acid digestion of environmental and biological samples and coal for the determination of both arsenic and selenium by hydride generation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Z.

1994-12-31

Hydride generation (HG) is a good sample introduction technique for the determination of As and Se, and has been widely used in atomic spectrometry. Several instrumental developments have been made in the hydride-generation system, however, sample digestion (pretreatment) is still the critical step in the FIG determination of As and Se in solid and semi-solid samples. The general digestion procedure with mineral acids is not suitable for complete decomposition of refractory organic compounds of As and Se present in some organic-rich materials, and then does not allow for the measurement of both As and Se in most environmental and biologicalmore » samples by HG. In this work, some well-designed experiments on the wet digestion in open system have been done with a temperature controlled sand bath. The oxidation performances of some mixtures of mineral acids and salts in different combinations have been investigated and evaluated with environmental and biological samples. With the use of HNO{sub 3}/HClO{sub 4} mixing with either the high-boiling-point acids (H{sub 2}SO{sub 4}, H{sub 3}PO{sub 4}) or some mineral salts(Mg(NO{sub 3}){sub 2}, MgSO{sub 4}, Na{sub 2}SO{sub 4}, NaH{sub 2}PO{sub 4}), the complete mineralization of organoarsenic and organoselenium compounds in the samples can be readily achieved while a dewatered step is in the employ of the digestion program. An improved wet digestion procedure with HNO{sub 3}/HClO{sub 4}/H{sub 3}PO{sub 4}(or Mg(NO{sub 3}){sub 2}, or MgSO{sub 4}) was investigated and optimized for the determination of both As and Se in sediment, soil, coal, fish and plant materials by HG-AAS. This method has been evaluated by the analyses of CRMs, including PACS-1, BCSS-1, MESS-11 DORM-1. DOLT-1. NIST-1632b, BCR-40 and BCR-181 for both As and Se, and good agreements with the certified values were obtained.« less

Removal kinetics for gaseous NO and SO2 by an aqueous NaClO2 solution mist in a wet electrostatic precipitator.

PubMed

Park, Hyun-Woo; Park, Dong-Wha

2017-04-01

Removal kinetics for NO and SO 2 by NaClO 2 solution mist were investigated in a wet electrostatic precipitator. By varying the molar concentrations of NO, SO 2 , and NaClO 2 , the removal rates of NO and SO 2 confirmed to range from 34.8 to 72.9 mmol/m 3  s and 36.6 to 84.7 mmol/m 3  s, respectively, at a fixed gas residence time of 0.25 s. The rate coefficients of NO and SO 2 were calculated to be 0.679 (mmol/m 3 ) -0.33  s -1 and 1.401 (mmol/m 3 ) -0.1  s -1 based on the rates of the individual removal of NO and SO 2 . Simultaneous removal of NO and SO 2 investigated after the evaluation of removal rates for their individual treatment was performed. At a short gas residence time, SO 2 gas removed more quickly by a mist of NaClO 2 solution than NO gas in simultaneous removal experiments. This is because SO 2 gas, which has a relatively high solubility in solution, was absorbed more rapidly at the gas-liquid interface than NO gas. NO and SO 2 gases were absorbed as nitrite [Formula: see text] and sulfite [Formula: see text] ions, respectively, by the NaClO 2 solution mist at the gas-liquid interface. Then, [Formula: see text] and [Formula: see text] were oxidized to nitrate [Formula: see text] and sulfate [Formula: see text], respectively, by reactions with [Formula: see text], ClO 2 , HClO, and ClO in the liquid phase.

Direct measurements of unimolecular and bimolecular reaction kinetics of the Criegee intermediate (CH 3) 2COO

DOE PAGES

Chhantyal-Pun, Rabi; Welz, Oliver; Savee, John D.; ...

2016-10-18

Here, the Criegee intermediate acetone oxide, (CH 3) 2COO, is formed by laser photolysis of 2,2-diiodopropane in the presence of O 2 and characterized by synchrotron photoionization mass spectrometry and by cavity ring-down ultraviolet absorption spectroscopy. The rate coefficient of the reaction of the Criegee intermediate with SO 2 was measured using photoionization mass spectrometry and pseudo-first-order methods to be (7.3 ± 0.5) × 10 –11 cm 3 s –1 at 298 K and 4 Torr and (1.5 ± 0.5) × 10 –10 cm 3 s –1 at 298 K and 10 Torr (He buffer). These values are similar tomore » directly measured rate coefficients of anti-CH 3CHOO with SO 2, and in good agreement with recent UV absorption measurements. The measurement of this reaction at 293 K and slightly higher pressures (between 10 and 100 Torr) in N 2 from cavity ring-down decay of the ultraviolet absorption of (CH 3) 2COO yielded even larger rate coefficients, in the range (1.84 ± 0.12) × 10 –10 to (2.29 ± 0.08) × 10 –10 cm 3 s –1. Photoionization mass spectrometry measurements with deuterated acetone oxide at 4 Torr show an inverse deuterium kinetic isotope effect, kH/kD = (0.53 ± 0.06), for reactions with SO 2, which may be consistent with recent suggestions that the formation of an association complex affects the rate coefficient. The reaction of (CD3)2COO with NO2 has a rate coefficient at 298 K and 4 Torr of (2.1 ± 0.5) × 10 –12 cm 3 s –1 (measured with photoionization mass spectrometry), again similar to rate for the reaction of anti-CH 3CHOO with NO 2. Cavity ring-down measurements of the acetone oxide removal without added reagents display a combination of first- and second-order decay kinetics, which can be deconvolved to derive values for both the self-reaction of (CH 3) 2COO and its unimolecular thermal decay. The inferred unimolecular decay rate coefficient at 293 K, (305 ± 70) s –1, is similar to determinations from ozonolysis. The present measurements confirm the large rate coefficient for reaction of (CH 3) 2COO with SO 2 and the small rate coefficient for its reaction with water. Product measurements of the reactions of (CH 3) 2COO with NO 2 and with SO 2 suggest that these reactions may facilitate isomerization to 2-hydroperoxypropene, possibly by subsequent reactions of association products.« less

Effects of inorganic electron acceptors on methanogenesis and methanotrophy and on the community structure of bacteria and archaea in sediments of a boreal lake

NASA Astrophysics Data System (ADS)

Rissanen, Antti J.; Karvinen, Anu; Nykänen, Hannu; Peura, Sari; Tiirola, Marja; Mäki, Anita; Kankaala, Paula

2016-04-01

Lake sediments are globally significant sources of CH4 to the atmosphere, but the factors controlling the production and consumption of CH4 in these systems are understudied. Increasing availability of electron acceptors (EA) (other than CO2) in sediments can decrease or even suppress CH4 production by diverting the electron flow (from H2 and organic substances) from methanogenic to other anaerobic respiration pathways. However, whether these changes in microbial function extend down to changes in the structure of microbial communities is not known. Also anaerobic oxidation of methane (AOM) could be enhanced by increased availability of EAs (SO42-, NO3-, Fe3+ and Mn4+), but information on the role of this process in lake sediments is scarce. We studied the effects of inorganic EAs on the potential for CH4 production and consumption and on the structure of microbial communities in sediments of a boreal lake. Anoxic slurries of sediment samples collected from two depths (0 - 10 cm; 10 - 30 cm) of the profundal zone of a boreal, mesotrophic Lake Ätäskö, were amended with 1) CH4 or with CH4 and either 2) 10 mM Mn4+, 3) 10 mM Fe3+, 4) O2 or 5) CH2F2 (inhibitor of aerobic methane oxidation) and incubated at +10° C for up to 4 months. Furthermore, slurries from the 10 - 30 cm layer were amended with CH4 and either 6) 2 mM NO3- or 7) 2 mM SO42- and incubated at +4 ° C for up to 14 months. The processes were measured using 13C-labelling and by concentration measurements of CH4 and CO2. Effects of treatments 1-3 on microbial communities were also analysed by next-generation sequencing of 16S rRNA, as well as methyl coenzyme-M reductase gene amplicons and mRNA transcripts. CH4 production (max. 83 nmol gdw-1d-1) took place in the anaerobic treatments but was generally decreased by the addition of NO3-, SO42-, Fe3+ and Mn4+. Although the structure of sediment archaeal community was resistant to Fe3+/Mn4+ - additions, slight changes in the structure of bacterial community occurred. Besides decreasing the availability of methanogenic substrates, the Mn4+/Fe3+ - induced changes in the bacterial community also probably decreased the H2:acetate - ratio in the substrate pool. This led to increase in the relative activity (mRNA level) of some operational taxonomic units assigned to aceticlastic Methanosaetaceae and decrease in the relative activity of hydrogenotrophic Methanoregulaceae in the sediment. CH4 oxidation (0.02 - 0.30 nmol gdw-1d-1 in anaerobic and 18 - 73 nmol gdw-1d-1in aerobic treatments) took place without EA additions and was enhanced only by O2. This suggests decoupling of the process from the reduction of other inorganic EAs. The results also indicate that Fe3+/Mn4+ - reduction did not increase CH4 oxidation via increased availability of SO42- by cryptic sulfur cycle or via increased availability of organic EAs. Furthermore, ANME - archaea were only ≤ 3% of sediment archaeal community and their relative activity was decreased during incubations. Thus, EA driving CH4 oxidation in the anoxic sediments of the lake remains unknown or the process was methanogen-driven via trace methane oxidation.

Characteristics of fine particulate matter and its sources in an industrialized coastal city, Ningbo, Yangtze River Delta, China

NASA Astrophysics Data System (ADS)

Wang, Weifeng; Yu, Jie; Cui, Yang; He, Jun; Xue, Peng; Cao, Wan; Ying, Hongmei; Gao, Wenkang; Yan, Yingchao; Hu, Bo; Xin, Jinyuan; Wang, Lili; Liu, Zirui; Sun, Yang; Ji, Dongsheng; Wang, Yuesi

2018-05-01

Chemical information is essential in understanding the characteristics of airborne particles, and effectively controlling airborne particulate matter pollution, but it remains unclear in some regions due to the scarcity of measurement data. In the present study, 92 daily PM2.5 (particulate matter with an aerodynamic diameter ≤ 2.5 μm) samples as well as historical observation data of air pollutants were collected in urban Ningbo, one of important industrial cities in the coastal area of the Yangtze River Delta, China in autumn and winter (from Nov. 2014 to Feb. 2015). Various chemical species in PM2.5 were determined including water soluble ions, organic and elemental carbon and elements. Positive matrix factorization model, cluster analysis of back trajectories, potential source contribution function (PSCF) model and concentration-weighted trajectory (CWT) model were used for identifying sources, apportioning contributions from each source and tracking potential areas of sources. The results showed the PM2.5 concentration has been reducing; nonetheless, the concentrations of PM2.5 are still much higher than the World Health Organization guideline with high PM2.5 concentrations observed in autumn and winter for the past few years. During the sampling period, the average PM2.5 mass concentration was 77 μg/m3 with the major components of OC, NO3-, SO42 -, NH4+ and EC, accounting for 24.7, 18.8, 14.5, 11.8 and 6.4% in the total mass concentration, respectively. When the aerosol pollution got worse during the sampling period, the NO3-, SO42 - and NH4+ concentrations increased accordingly and NO3- appeared to increase at fastest rate. SO42 - transported from industrial areas led to slight difference in spatial distribution of SO42 - in Ningbo. More secondary organic carbon was formed and the enrichment factor values of Cu, Ag, Cd, Sn and Pb increased with the degradation of air quality. Ten types of sources were identified for PM2.5 in the autumn and winter of Ningbo, which are metallurgical industry, biomass burning and waste incineration, manufacturing related with Mo, chlor-alkli chemical industry, oil combustion, vehicular emission, secondary source, soil dust, road dust and manufacturing related with Cr, accounting for 9.4, 4.8, 9.4, 7.6, 8.1, 18.7, 27.6, 2, 7.1 and 5.2% of the total sources, respectively. There were five groups of air parcels arriving in Ningbo, of which inland air masses originating from Shandong province were associated with the highest PM2.5 concentrations. Despite the slight differences, it was obvious that the north of Jiangxi, east of Anhui, west of Jiangsu, south of Shandong were identified as major potential sources-areas of SO42 -, NO3-, NH4+, Cl-, OC and EC by both PSCF and CWT models.

Rb3In(H2O)Si5O13: a novel indium silicate with a CdSO4-topological-type structure.

PubMed

Hung, Ling-I; Wang, Sue-Lein; Chen, Chia-Yi; Chang, Bor-Chen; Lii, Kwang-Hwa

2005-05-02

A novel indium silicate, Rb3In(H2O)Si5O13, has been synthesized using a high-temperature, high-pressure hydrothermal method and characterized by single-crystal X-ray diffraction. The structure consists of five-membered rings of corner-sharing SiO4 tetrahedra connected via corner sharing to four adjacent five-membered rings to form a 3D silicate framework that belongs to the CdSO4 topological type. The InO6 octahedron shares five of its corners with five different SiO4 tetrahedra to form a 3D frame-work that delimits two types of channels to accommodate the rubidium cations. The sixth corner of InO6 is coordinated H2O. The structure is related to that of the titanium silicate ETS-10, and these are the only two metal silicates that have the CdSO4-topological-type structure. In addition, the crystal of Rb3In(H2O)Si5O13 shows an intense second harmonic generation signal. Crystal data: H2Rb3InSi5O14, monoclinic, space group Cc (No. 9), a = 9.0697(5) A, b = 11.5456(6) A, c = 13.9266(8) A, beta = 102.300(1) degrees, V = 1424.8(1) A3, and Z = 4.

Characteristic Study of Some Different Kinds of Coal Particles Combustion with Online TG-MS-FTIR

NASA Astrophysics Data System (ADS)

Pan, Guanfu

2018-01-01

Four kinds of pulverized coal samples from China and Indonesia were studied by thermogravimetry coupled with mass spectrometry and fourier transform infrared spectroscopy (TG-MS-FTIR). The thermal behaviors and gaseous emissions of these coals were analyzed in this work. The results indicate that the relative lower values of H/C ratios, which normally represent the degree of aromatization and ring condensation in coal samples, could lead to the relative more intense thermal reaction. The time-evolved profiles of some typical gas products (i.e., CO, SO2, CH4, NO, NO2, NH3 and etc.) were provided by TG-MS-FTIR, and their variations are different. For all the samples, the releases of SO2 and COS can be found at lower temperature than those of NO and CO. As the temperature increases, the possible conversion of NO2 and NH3 to NO is deduced in this work.

Synthesis, Characterization and Cytotoxicity Studies of Palladium(II)-Proflavine Complexes

PubMed Central

Polyanskaya, Tatyana V.; Kazhdan, Irene; Motley, D. Michelle; Walmsley, Judith A.

2010-01-01

An investigation of the reaction of Pd(II) complexes with proflavine (3,6-diaminoacridine) resulted in the isolation of the compounds [Pd(terpy)(proflavine)](NO3)(HSO4)·3H2O, 1, (terpy = 2,2’:6’,2”-terpyridine), [Pd(en)(proflavineH))](NO3)(SO4), 2, (en = ethylenediamine), and [Pd(proflavineH)Cl2](SO4)0.5 ·H2O, 3. They have been isolated and characterized by NMR, IR, and electrospray ionization mass spectrometry techniques and by elemental analyses. The proflavine was bonded to the Pd(II) through the endocyclic nitrogen in 1, but through the proflavine NH2 in 2. Compound 3 appeared to be polymeric in the solid state with a 1:1 mole ratio of Pd(II):proflavine. Upon solution of 3 in DMSO, two unique species were formed. In one species the Pd(II) was bonded to Two proflavines through the endocyclic nitrogen (1:2 mole ratio) and in the other species, a Pd(II) was bonded to each NH2 group of a single proflavine (2:1 mole ratio). Molecular modeling of the equilibrium geometry by Spartan 8 produced structures which were consistent with the experimental data on the solutions of the three compounds. In vitro cytotoxicity testing against two breast cancer cell lines and one ovarian cancer cell line showed that compounds 1 and 3 had significant activity. PMID:20709409

PCB and DDE methyl sulfones in mammals from Canada and Sweden

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bergman, A.; Kuroki, Hiroaki; Norstrom, R.J.

1994-01-01

Levels of PCB methyl sulfones (MeSO[sub 2]-CBs) and DDE methyl sulfones (MeSO[sub 2]-DDEs) have been determined in tissues from polar bear (Ursus martimus), beluga whale (Delphinapterus leucas), and false killer whale (Pseudorca crassidens) from the Canadian environment, and grey seal (Halichoerus grypus), otter (Lutra lutra), and wild mink (Mustela vison) from the Swedish environment. Up to 30 MeSO[sub 2]-CB congeners and three MeSO[sub 2]-DdE isomers were shown to be present in the analyzed tissues. The concentration of total MeSO[sub 2]-CBs ranged from 0.1 to 21 [mu]g/g extracted lipids. 3-MeSO[sub 2]-2,5,2[prime],4[prime],5[prime]-penta-CB is the dominating MeSO[sub 2]-CB congener in all the analyzedmore » samples, but the corresponding 4-MeSO[sub 2]-CB also is present in high concentrations. A smaller number of MeSO[sub 2]-CBs, always dominated by the meta-substituted MeSO[sub 2]-CBs, were present in livers of grey seal, otter, and mink than in adipose tissue or muscle. In all studied mammals the concentration of MeSO[sub 2]-CBs were higher in liver than in blubber or muscle. Seven PCB congeners were identified as precursors of the PCB methyl sulfones: 2,4,2[prime],5[prime]-tetra-CB (CB-49),2,5,3[prime],4[prime]-tetra-CB (CB-70), 2,4,5,2[prime],5[prime]-penta-CB (CB-101),2,3,4,5,2[prime],5[prime]-penta-CB (CB-87),2,3,6,2[prime],4[prime],5[prime]-hexa-CB (CB-149),2,3,4,2[prime],3[prime],6[prime]-hexa-CB (CB-132), and 2,3,4,2[prime],5[prime]-hexa-CB (CB-141). All species except beluga whale contained 3-MeSO[sub 2]-4,4[prime]-DDE, but at a much lower concentration in mink and otter than in the other mammals. Polar bear and grey seal liver also contained 2-MeSO[sub 2]-4,4[prime]-DDE. The concentration of 2- and 3-MeSo[sub 2]-DDE ranged from 0.01 to 1.3 [mu]g/g extracted lipids.« less

Chemical trends in background air quality and the ionic composition of precipitation for the period 1980-2004 from samples collected at Valentia Observatory, Co. Kerry, Ireland.

PubMed

Bashir, Wasim; McGovern, Frank; O'Brien, Phillip; Ryan, Margaret; Burke, Liam; Paull, Brett

2008-06-01

A major Irish study, based upon more than 8000 samples collected over the measurement period of 22 years, for sulfur dioxide (SO2-S), sulfate (SO4-S) and nitrogen dioxide (NO2-N) concentrations (microg m(-3)) within air, and the ionic composition of precipitation samples based on sodium (Na+), potassium (K+), magnesium (Mg2+), calcium (Ca2+), chloride (Cl-), sulfate (SO4-S), non-sea salt sulfate (nssSO4-S), ammonium (NH4-N), and nitrate (NO3-N) weighted mean concentrations (mg l(-1)), has been completed. For the air samples, the sulfur dioxide and sulfate concentrations decreased over the sampling period (1980-2004) by 75% and 45%, respectively, whereas no significant trend was observed for nitrogen dioxide. The highest concentrations for sulfur dioxide, sulfate and nitrogen dioxide were associated with wind originating from the easterly and northeasterly directions i.e. those influenced by Irish and European sources. The lowest concentrations were associated with the westerly directions i.e. for air masses originating in the North Atlantic region. This was further verified with the use of backward (back) trajectory analysis, which allowed tracing the movement of air parcels using the European Centre for Medium range Weather Forecasting (ECMWF) ERA-40 re-analysis data. High non-sea salt sulfate levels were being associated with air masses originating from Europe (easterlies) with lower levels from the Atlantic (westerlies). With the precipitation data, analysis of the non-sea salt sulfate concentrations showed a decrease by 47% since the measurements commenced.

High covalence in CuSO4 and the radicalization of sulfate: an X-ray absorption and density functional study.

PubMed

Szilagyi, Robert K; Frank, Patrick; DeBeer George, Serena; Hedman, Britt; Hodgson, Keith O

2004-12-27

Sulfur K-edge X-ray absorption spectroscopy (XAS) of anhydrous CuSO(4) reveals a well-resolved preedge transition feature at 2478.8 eV that has no counterpart in the XAS spectra of anhydrous ZnSO(4) or copper sulfate pentahydrate. Similar but weaker preedge features occur in the sulfur K-edge XAS spectra of [Cu(itao)SO(4)] (2478.4 eV) and [Cu[(CH(3))(6)tren]SO(4)] (2477.7 eV). Preedge features in the XAS spectra of transition metal ligands are generally attributed to covalent delocalization of a metal d-orbital hole into a ligand-based orbital. Copper L-edge XAS of CuSO(4) revealed that 56% of the Cu(II) 3d hole is delocalized onto the sulfate ligand. Hybrid density functional calculations on the two most realistic models of the covalent delocalization pathways in CuSO(4) indicate about 50% electron delocalization onto the sulfate oxygen-based 2p orbitals; however, at most 14% of that can be found on sulfate sulfur. Both experimental and computational results indicated that the high covalence of anhydrous CuSO(4) has made sulfate more like the radical monoanion, inducing an extensive mixing and redistribution of sulfur 3p-based unoccupied orbitals to lower energy in comparison to sulfate in ZnSO(4). It is this redistribution, rather than a direct covalent interaction between Cu(II) and sulfur, that is the origin of the observed sulfur XAS preedge feature. From pseudo-Voigt fits to the CuSO(4) sulfur K-edge XAS spectrum, a ground-state 3p character of 6% was quantified for the orbital contributing to the preedge transition, in reasonable agreement with the DFT calculation. Similar XAS fits indicated 2% sulfur 3p character for the preedge transition orbitals in [Cu(itao)SO(4)] and [Cu[(CH(3))(6)tren]SO(4)]. The covalent radicalization of ligands similar to sulfate, with consequent energy redistribution of the virtual orbitals, represents a new mechanism for the induction of ligand preedge XAS features. The high covalence of the Cu sites in CuSO(4) was found to be similar to that of Cu sites in oxidized cupredoxins, including its anistropic nature, and can serve as the simplest inorganic examples of intramolecular electron-transfer processes.

Recent results on aqueous electrolyte cells

NASA Astrophysics Data System (ADS)

Wessells, Colin; Huggins, Robert A.; Cui, Yi

2011-03-01

The improved safety of aqueous electrolytes makes aqueous lithium-ion batteries an attractive alternative to commercial cells utilizing flammable and expensive organic electrolytes. Two important issues relating to their use have been addressed in this work. One is the extension of the usable voltage range by the incorporation of lithium salts, and the other is the investigation of a useful negative electrode reactant, LiTi2(PO4)3. The electrochemical stability of aqueous lithium salt solutions containing two lithium salts, LiNO3 and Li2SO4, has been characterized using a constant current technique. In both cases, concentrated solutions had effective electrolyte stability windows substantially greater than that of pure water under standard conditions. At an electrolyte leakage current of 10 μA cm-2 between two platinum electrodes in 5 M LiNO3 the cell voltage can reach 2.0 V, whereas with a leakage current of 50 μA cm-2 it can reach 2.3 V. LiTi2(PO4)3 was synthesized using a Pechini method and cycled in pH-neutral Li2SO4. At a reaction potential near the lower limit of electrolyte stability, an initial discharge capacity of 118 mAh g-1 was measured at a C/5 rate, while about 90% of this discharge capacity was retained after 100 cycles. This work demonstrates that it is possible to have useful aqueous electrolyte lithium-ion batteries using the LiTi2(PO4)3 anode with cell voltages of 2 V and above.

Ammonia Vapor-Assisted Synthesis of Cu(OH)2 and CuO Nanostructures: Anionic (Cl-, NO3 -, SO4 2-) Influence on the Product Morphology

NASA Astrophysics Data System (ADS)

Mansournia, Mohammadreza; Arbabi, Akram

2017-01-01

Shape control of inorganic nanostructures generally requires using surfactants or ligands to passivate certain crystallographic planes. This paper describes a novel additive-free synthesis of cupric oxide nanostructures with different morphologies from the aqueous solutions of copper(II) with Cl-, NO3 -, and SO4 2- as counter ions. Through a one-step approach, CuO nanoleaves, nanoparticles and flower-like microspheres were directly synthesized at 80°C upon exposure to ammonia vapor using a cupric solution as a single precursor. Furthermore, during a two-step process, Cu(OH)2 nanofibers and nanorods were prepared under an ammonia atmosphere, then converted to CuO nanostructures with morphology preservation by heat treatment in air. The as-prepared Cu(OH)2 and CuO nanostructures are characterized using x-ray diffraction, scanning electron microscopy and Fourier transformation infrared spectroscopy techniques.

Comparison of physical and chemical properties of ambient aerosols during the 2009 haze and non-haze periods in Southeast Asia.

PubMed

Xu, Jingsha; Tai, Xuhong; Betha, Raghu; He, Jun; Balasubramanian, Rajasekhar

2015-10-01

Recurrent smoke-haze episodes that occur in Southeast Asia (SEA) are of much concern because of their environmental and health impacts. These haze episodes are mainly caused by uncontrolled biomass and peat burning in Indonesia. Airborne particulate matter (PM) samples were collected in the southwest coast of Singapore from 16 August to 9 November in 2009 to assess the impact of smoke-haze episodes on the air quality due to the long-range transport of biomass and peat burning emissions. The physical and chemical characteristics of PM were investigated during pre-haze, smoke-haze, and post-haze periods. Days with PM2.5 mass concentrations of ≥35 μg m(-3) were considered as smoke-haze events. Using this criterion, out of the total 82 sampling days, nine smoke-haze events were identified. The origin of air masses during smoke-haze episodes was studied on the basis of HYSPLIT backward air trajectory analysis for 4 days. In terms of the physical properties of PM, higher particle surface area concentrations and particle gravimetric mass concentrations were observed during the smoke-haze period, but there was no consistent pattern for particle number concentrations during the haze period as compared to the non-haze period except that there was a significant increase at about 08:00, which could be attributed to the entrainment of PM from aloft after the breakdown of the nocturnal inversion layer. As for the chemical characteristics of PM, among the six key inorganic water-soluble ions (Cl(-), NO3(-), nss-SO4(2-), Na(+), NH4(+), and nss-K(+)) measured in this study, NO3(-), nss-SO4(2-), and NH4(+) showed a significant increase in their concentrations during the smoke-haze period together with nss-K(+). These observations suggest that the increased atmospheric loading of PM with higher surface area and increased concentrations of optically active secondary inorganic aerosols [(NH4)2SO4 or NH4HSO4 and NH4NO3] resulted in the atmospheric visibility reduction in SEA due to the advection of biomass and peat burning emissions.

Preparation of Solvent-Dispersible Graphene and its Application to Nanocomposites

DTIC Science & Technology

2016-06-14

sulfuric acid (H2SO4), hydrochloric acid (HCl), hydrogen peroxide (H2O2), potassium permanganate (KMnO4), and sodium nitrate (NaNO3) were...then added to reduce the unreacted permanganate . The mixture was then filtered through a cellulose filter and washed sequentially with dilute HCl and

Experimental study and kinetic modeling of hydrogen and carbon monoxide oxidation perturbed by nitrogen and sulfur oxides

NASA Astrophysics Data System (ADS)

Mueller, Mark Anthony

2000-10-01

Increasingly stringent regulations have and will likely continue to place considerable constraints on combustion-generated pollutants, including carbon monoxide, nitrogen oxides, and sulfur oxides. The speciation of these pollutants and, by extension, their impact, is likely affected by kinetic interactions that occur during post-combustion processes. To gain a fundamental understanding of these interactions, the oxidation of hydrogen and carbon monoxide in the presence of trace quantities of NO, NO2, and SO2 was experimentally and numerically studied at conditions relevant to modern internal combustion engines. Experimental data were obtained using a well-characterized flow reactor over pressure and temperature ranges of 0.4--14.0 atm and 750--1040 K, respectively, using dilute (˜1% fuel) H2/O2 and CO/H2O/O2 mixtures perturbed with ppm quantities of NO, NO2, and/or SO2. The overall effects of these species were found to be highly sensitive to pressure, temperature, and equivalence ratio. In general, small quantities of NO promoted fuel consumption by converting HO2 radicals to highly reactive OH radicals, while high concentrations of NO and/or NO2 were inhibiting due to the catalysis of radical recombination reactions. In the absence of NO, SO2 strongly inhibited CO oxidation, but the simultaneous presence of NO and SO2 yielded synergistic effects that significantly reduced the inhibition from SO 2. Over the range of conditions explored, direct interactions between NOx and SOx species did rot appear to significantly influence the relative NO and NO2 concentrations; however, the reaction between NO2 and SO2 may be an important source of SO3 in certain circumstances. A detailed reaction mechanism. has been developed in a hierarchical manner, beginning with the H2/O2 and CO/H2O/O 2 systems and sequentially adding reactions necessary to describe the perturbing effects of NOx and SOx species. The experimental data were used in conjunction with gradient sensitivity and reaction flux analyses to determine key reaction pathways and to derive rate data for the H+O2(+M)=HO2(+M), H2+NO2=HONO+H, and SO2+O(+M) SO3(+M) reactions. Modifications to the rate constants for these and other reactions are discussed in relation to the mechanism's predictive ability with respect to the H2/O 2, CO/H2O/O2, H2/NO2, H 2/O2/NOx, and CO/H2O/O2/NO x/SOx systems over a wide range of conditions.

Ambient air pollution and completed suicide in 26 South Korean cities: Effect modification by demographic and socioeconomic factors.

PubMed

Lee, Hyewon; Myung, Woojae; Kim, Satbyul Estella; Kim, Doh Kwan; Kim, Ho

2018-10-15

Air pollution has been recently associated with suicide mortality. However, limited studies have examined possible effect modification of the association by various demographic and socioeconomic factors, despite their crucial roles on suicide risk. In 73,445 completed suicide cases from 26 South Korean cities from 2002 to 2013, we studied the association of suicide risk with exposure to particles <10 μm (PM 10 ), nitrogen dioxide (NO 2 ), sulfur dioxide (SO 2 ), ozone (O 3 ), and carbon monoxide (CO), using a city-specific conditional logistic regression analysis with a case-crossover design. Random effects meta-analysis was used to pool the results. We considered a delayed effect of air pollution by constructing lags of up to 7 days. We explored effect modification by demographic and socioeconomic factors (sex, age, education level, job, and marital status) as well as place of death, method of suicide, and season, through stratified subgroup analyses. Among five pollutants, NO 2 showed the strongest association at immediate lags (percent change in odds ratio; PM 10 : 1.2% [95% CI, 0.2%, 2.3%]; NO 2 : 4.3% [95% CI, 1.9%, 6.7%]; SO 2 : 2.2% [95% CI, 0.7%, 3.8%]; O 3 : 1.5% [95% CI, -0.3%, 3.2%]; and CO: 2.4% [95% CI, 0.9%, 3.8%] per interquartile range increase at lag0). In subgroup analyses by socioeconomic factors, stronger associations were observed in the male sex, the elderly, those with lower education status, white-collar workers, and the married; the largest association was an 11.0% increase (95% CI, 4.1%, 18.4%) by NO 2 among white-collar workers. We add evidence of effect modification of the association between air pollution exposure and suicide risk by various demographic and socioeconomic factors. These findings can serve as the basis for suicide prevention strategies by providing information regarding susceptible subgroups. Copyright © 2018 Elsevier B.V. All rights reserved.

[Effect of developing tourism on chemical characteristic of precipitation: taking Lijiang for example].

PubMed

Zhang, Ning-Ning; He, Yuan-Qing; Wang, Chun-Feng; Pang, Hong-Xi; He, Xian-Zhong

2011-02-01

1090 precipitation samples were collected from 1989 to 2006 at Lijiang City. The analyzed results indicate that the average pH value is 6.08 at study period, which is higher than the average pH value (5.0) during 1987 to 1989, and the annual pH value show an increasing trend, suggesting there are more alkaline mass input to air after 1989. the concentrations of major ions Cl-, SO4(2-), NO3-, Na+, Ca2+, Mg2+ and NH4+ are 11.56, 32.64, 3.63, 2.54, 50.19, 7.73 and 11.36 microeq x L(-1), respectively. By computed the correlation coefficients and sources contribution among major ions, it find that Ca2+ and Mg2+ are from soil-derived sources, and about 57.2% of SO4(2-) also come from soil-derived sources; 95.4% of total NO3- and 41.9% of SO4(2-) come from anthropogenic sources, and only Na+ and 25.7% of Cl- come from sea source, meaning that the chemical composition of precipitation at Lijiang region is main influenced by regional sources. According to the variation of tour scale at Lijiang city, it can be divided into 3 periods of 1987-1989, 1989-1996 and 1997-2006. The percent of soil-derived ions at different periods is 40%, 53% and 72%, respectively, showing a significant increase trend; but the percent of anthropology-derived ions at different periods is 39%, 36% and 15%, respectively, showing a decrease trend. It explains that more dust input to the air by expending city scale, changing the land form and overusing water resources. But in order to develop tourism, the pollutants related to industries are controlled well.

Influence of sulfur dioxide on the respiratory system of Miyakejima adult residents 6 years after returning to the island.

PubMed

Kochi, Takeshi; Iwasawa, Satoko; Nakano, Makiko; Tsuboi, Tazuru; Tanaka, Shigeru; Kitamura, Hiroko; Wilson, Donald John; Takebayashi, Toru; Omae, Kazuyuki

2017-07-27

Mount Oyama, on the Japanese island of Miyakejima, began erupting in June 2000, necessitating the evacuation of 3,000 island residents. Volcanic gas emissions, primarily consisting of sulfur dioxide (SO 2 ), gradually decreased and residents returned to the island after the evacuation order was lifted in February 2005. To assess the exposure-effect and exposure-response relationships between SO 2 exposure and effects on respiratory system in adult Miyakejima residents. Health checkups focusing on pulmonary function and respiratory/irritative symptoms were conducted six times every November from 2006 to 2011. The study population comprised 168 subjects who underwent all health checkups. SO 2 concentrations were measured at six fixed monitoring stations in inhabitable areas. Based on the annual mean SO 2 concentration, inhabitable areas were classified into three categories; namely, lower (L), higher (H-1), and highest (H-2) areas. Average SO 2 concentrations (ppb) during 3 months prior to each health checkup dropped from 11.3 to 3.29, 32.2 to 13.4 and 75.1 to 12.6 from 2006 to 2010/2011 in L, H-1, and H-2. No significant declines in pulmonary function were observed in all areas. However, prevalence of subjective symptoms such as "Cough," "Irritation and/or pain in throat," "Irritation, runny nose, and/or nasal sniffles," and "Irritation and/or pain in the eyes," dependently increased on SO 2 concentration. Odds ratios were statistically significant at approximately 70 ppb of SO 2 or above. Adult residents of Miyakejima island showed no deterioration in pulmonary function at SO 2 levels, but complained of respiratory/irritative symptoms in an SO 2 concentration-dependent manner.

Renal Denervation Attenuates Progression of Atherosclerosis in Apolipoprotein E–Deficient Mice Independent of Blood Pressure Lowering

PubMed Central

Wang, Hui; Wang, Jintao; Guo, Chiao; Luo, Wei; Kleiman, Kyle; Eitzman, Daniel T.

2016-01-01

The renal autonomic nervous system may contribute to hypertension and vascular disease. Although the effects of renal artery denervation on blood pressure lowering are controversial, there may be other beneficial vascular effects independent of blood pressure lowering. Bilateral renal denervation (RDN) or sham operation (SO) was performed in 14-week-old male apolipoprotein E–deficient mice on a Western diet starting at 10 weeks of age. Efficacy of RDN was confirmed by reduction of renal norepinephrine levels (SO: 3.8±0.1 versus RDN: 1.7±0.3 ng/mL; P<0.01) at 6 weeks after procedure. Compared with SO, RDN had no effect on blood pressure (SO: 101.0±2.4 versus RDN: 97.5±1.6 mm Hg; P=0.25), total cholesterol (SO: 536.7±28.5 versus RDN: 535.7±62.9 mg/dL; P=0.99), or triglycerides (SO: 83.7±3.5 versus RDN: 86.9±10.2 mg/dL; P=0.78). Quantification of atherosclerosis at 20 weeks of age demonstrated reduced atherosclerosis in mice receiving RDN compared with SO (arterial tree oil-red-O surface staining RDN: 4.2±0.5% versus SO: 6.3±0.7%; P<0.05). Reduced atherosclerosis was associated with increased smooth muscle cell content in atherosclerotic plaques (RDN: 13.3±2.1 versus SO: 8.1±0.6%; P<0.05). Serum levels of aldosterone, monocyte chemoattractant protein-1, and 8-isoprostane were lower in mice that received RDN compared with sham-operated mice (aldosterone; RDN: 206.8±33.2 versus SO: 405.5±59.4 pg/mL, P<0.05; monocyte chemoattractant protein-1; RDN: 51.7±7.9 versus SO: 91.71±4.6 pg/mL, P<0.05; 8-isoprostane; RDN: 331.9±38.2 versus SO: 468.5±42.0 pg/mL, P<0.05). RDN reduces progression of atherosclerosis in apolipoprotein E–deficient mice. These changes are associated with reduced aldosterone levels, monocyte chemoattractant protein-1, and markers of oxidative stress. PMID:25646301

Inhibition of bacterial oxidation of ferrous iron by lead nitrate in sulfate-rich systems.

PubMed

Wang, Hongmei; Gong, Linfeng; Cravotta, Charles A; Yang, Xiaofen; Tuovinen, Olli H; Dong, Hailiang; Fu, Xiang

2013-01-15

Inhibition of bacterial oxidation of ferrous iron (Fe(II)) by Pb(NO(3))(2) was investigated with a mixed culture of Acidithiobacillus ferrooxidans. The culture was incubated at 30 °C in ferrous-sulfate medium amended with 0-24.2 mM Pb(II) added as Pb(NO(3))(2). Anglesite (PbSO(4)) precipitated immediately upon Pb addition and was the only solid phase detected in the abiotic controls. Both anglesite and jarosite (KFe(3)(SO(4))(2)(OH)(6)) were detected in inoculated cultures. Precipitation of anglesite maintained dissolved Pb concentrations at 16.9-17.6 μM regardless of the concentrations of Pb(NO(3))(2) added. Fe(II) oxidation was suppressed by 24.2 mM Pb(NO(3))(2) addition even when anglesite was removed before inoculation. Experiments with 0-48 mM KNO(3) demonstrated that bacterial Fe(II) oxidation decreased as nitrate concentration increased. Therefore, inhibition of Fe(II) oxidation at 24.2 mM Pb(NO(3))(2) addition resulted from nitrate toxicity instead of Pb addition. Geochemical modeling that considered the initial precipitation of anglesite to equilibrium followed by progressive oxidation of Fe(II) and the precipitation of jarosite and an amorphous iron hydroxide phase, without allowing plumbojarosite to precipitate were consistent with the experimental time-series data on Fe(II) oxidation under biotic conditions. Anglesite precipitation in mine tailings and other sulfate-rich systems maintains dissolved Pb concentrations below the toxicity threshold of A. ferrooxidans. Copyright © 2012 Elsevier B.V. All rights reserved.

Chemical characteristics and temporal trends in eight streams of the Catskill Mountains, New York

USGS Publications Warehouse

Murdoch, Peter S.; Stoddard, J.L.

1993-01-01

Discharge to concentration relationships for eight streams studied by the U.S. Geological Survey (USGS) as part of the U.S. Environmental Protection Agency's (U.S. EPA) Long-Term Monitoring Project (1983-89) indicate acidification of some streams by H2SO4 and HNO3 in atmospheric deposition and by organic acids in soils. Concentrations of major ions in precipitation were similar to those reported at other sites in the northeastern United States. Average concentrations of SO42- and NO3- were similar among streams, but base cation concentrations differed widely, and these differences paralleled the differences in acid neutralizing capacity (ANC). Baseflow ANC is not a reliable predictor of stream acidity at high flow; some streams with high baseflow ANC (> 150 ??eq L-1) declined to near zero ANC at high flow, and one stream with low baseflow ANC (< 50 ??eq L-1) did not approach zero ANC as flow increased. Episodic decreases in ANC and pH during peak flows were associated with increased concentrations of NO3- and dissolved organic carbon (DOC). Aluminum concentrations exceeding 300 ??g L-1 were observed during peak flows in headwater streams of the Neversink River and Rondout Creek. Seasonal Kendall Tau tests for temporal trends indicate that SO42- concentrations in streamwater generally decreased and NO3- concentrations increased during the period 1983-1989. Combined acid anion concentrations (SO42- + NO3-) were generally unchanged throughout the period of record, indicating both that the status of these streams with respect to acidic deposition is unchanged, and that NO3- is gradually replacing SO42- as the dominant acid anion in the Catskill streams.Discharge to concentration relationships for eight streams studied by the US Geological Survey (USGS) as part of the Environmental Protection Agency's (US EPA) Long-term monitoring project (19831-89) indicate acidification of some streams by H2SO4 and HNO3 in atmospheric deposition and by organic acids in soils. Concentrations of major ions in precipitations were similar to those reported at other sites in the northeastern United States. Average concentrations of SO42- and No3- were similar among streams, but base cation concentrations differed widely, and these differences parallelel the differences in acid neutralizing capacity (ANC).

Using dual isotopes to evaluate sources and transformations of nitrate in the West Lake watershed, eastern China

NASA Astrophysics Data System (ADS)

Jin, Zanfang; Qin, Xue; Chen, Lingxiao; Jin, Mantong; Li, Feili

2015-06-01

The West Lake is a World Heritage site in the West Lake watershed in eastern China. In this study, the hydrogeological and dual isotopic approaches were integrated to evaluate the seasonal and spatial variations of nitrate (NO3-) in the West Lake watershed, and to characterize NO3- sources and transformations. The results revealed that the geochemical facies of the water samples were dominated by Ca2 + + Na+-HCO3- + SO42- in the surface water and transfer water, Ca2 + + Na+-HCO3- and Ca2 + + Na+-SO42 - in the groundwater, which most likely reflect natural reactions and anthropogenic inputs. About 13% of the groundwater samples containing NO3- exceeded the World Health Organization (WHO) standard of 10 mg N L- 1. NO3- was the dominant form of total nitrogen (TN) and was the main surface water contaminant in the West Lake watershed. The δ15NNO3 and δ18ONO3 values indicated that the dominant NO3- sources in surface water were soil nitrogen (soil N) and chemical fertilizers, while the main NO3- sources in groundwater were soil N from the forest, chemical fertilizers and manure in the tea garden, domestic sewage from the small, old residential area in the forest as well as urban areas. The distribution of NO3- in groundwater was strongly influenced by land use. Results also suggest that there was significant nitrification in surface water and groundwater in the West Lake watershed, and that there were also denitrification processes in groundwater. The annual net fluxes of TN, NO3-, and NH4+ into the West Lake were 2.0 × 104, 4.0 × 103, and 1.31 × 104 kg as N, respectively.

Synthetic, Infrared, 1Hand 13CNMR Spectral Studies on N-(p-Substituted Phenyl)-p-Substituted Benzenesulphonamides, p-X'C6H4SO2NH- (p-XC6H4), where X' or X = H, CH3, C2H5, F, Cl or Br

NASA Astrophysics Data System (ADS)

Gowda, B. Thimme; Jayalakshmi, K. L.; Shetty, Mahesha

2004-05-01

Thirty N-(p-substituted phenyl)-p-substituted benzenesulphonamides of the general formula, p-X'C6H4SO2NH(p-XC6H4), where X' or X = H, CH3, C2H5, F, Cl or Br, are synthesised and their infrared spectra in the solid state and 1H and 13C NMR spectra in solution are measured. The N-H stretching vibrational frequencies, νN-H vary in the range 3334 - 3219 cm-1, while the asymmetric and symmetric SO2 vibrations appear in the ranges 1377 - 1311 cm-1 and 1182 - 1151 cm-1, respectively. The compounds exhibit S-N and C-N stretching vibrational absorptions in the ranges 937 - 898 cm-1 and 1310 - 1180 cm-1, respectively. There are no particular trends in the variation of these frequencies on substitution with either electron withdrawing or electron donating groups. The 1H and 13C chemical shifts of N-(p-substituted phenyl)-p-substituted benzenesulphonamides, are assigned to various protons and carbons of the two benzene rings. Further, incremental shifts of the ring protons and carbons due to -SO2NH(p-XC6H4) groups in the compounds of the formula, C6H5SO2NH(p-XC6H4), and p-X'C6H4SO2- and p-X'C6H4SO2NH- groups in the compounds of the formula, p-X'C6H4SO2NH(C6H5) are computed and used to calculate the 1H and 13C chemical shifts of the parallely substituted compounds of the general formula p-X'C6H4SO2NH(p-XC6H4). The computed values agree well with the observed chemical shifts. The above incremental shifts are found to correlate with the Hammett substituent parameters.

Water soluble aerosols and gases at a UK background site - Part 1: Controls of PM2.5 and PM10 aerosol composition

NASA Astrophysics Data System (ADS)

Twigg, M. M.; Di Marco, C. F.; Leeson, S.; van Dijk, N.; Jones, M. R.; Leith, I. D.; Morrison, E.; Coyle, M.; Proost, R.; Peeters, A. N. M.; Lemon, E.; Frelink, T.; Braban, C. F.; Nemitz, E.; Cape, J. N.

2015-07-01

There is limited availability of long-term, high temporal resolution, chemically speciated aerosol measurements which can provide further insight into the health and environmental impacts of particulate matter. The Monitor for AeRosols and Gases (MARGA, Applikon B.V., NL) allows for the characterisation of the inorganic components of PM10 and PM_{2.5 (NH4+, NO3-, SO42-, Cl-, Na+, K+, Ca2+, Mg2+) and inorganic reactive gases (NH3, SO2, HCl, HONO and HNO3) at hourly resolution. The following study presents 6.5 years (June 2006 to December 2012) of quasi-continuous observations of PM2.5 and PM10 using the MARGA at the UK EMEP supersite, Auchencorth Moss, SE Scotland. Auchencorth Moss was found to be representative of a remote European site with average total water soluble inorganic mass of PM2.5 of 3.82 μg m-3. Anthropogenically derived secondary inorganic aerosols (sum of NH4+, NO3- and nss-SO42-) were the dominating species (63 %) of PM2.5. In terms of equivalent concentrations, NH4+ provided the single largest contribution to PM2.5 fraction in all seasons. Sea salt was the main component (73 %) of the PMcoarse fraction (PM10-PM2.5), though NO3- was also found to make a relatively large contribution to the measured mass (17 %) providing evidence of considerable processing of sea salt in the coarse mode. There was on occasions evidence of aerosol from combustion events being transported to the site in 2012 as high K+ concentrations (deviating from the known ratio in sea salt) coincided with increases in black carbon at the site. Pollution events in PM10 (defined as concentrations > 12 μg m-3) were on average dominated by NH4+ and NO3-, where smaller loadings at the site tended to be dominated by sea salt. As with other western European sites, the charge balance of the inorganic components resolved were biased towards cations, suggesting the aerosol was basic or more likely that organic acids contributed to the charge balance. This study demonstrates the UK background atmospheric composition is primarily driven by meteorology with sea salt dominating air masses from the Atlantic Ocean and the Arctic, whereas secondary inorganic aerosols tended to dominate air masses from continental Europe.}

Ammonium Sulfate Evaporites Associated With Uranium Mill Tailings Disposal Cells

NASA Astrophysics Data System (ADS)

Wendlandt, R. F.; Harrison, W. J.

2006-12-01

The waste products of uranium mill operations are complex and dependent on the ore mineralogy, milling process (e.g., low pH vs. high pH), and operational status of the mill among other things. The White Mesa Mill, Utah, was visited during both quiescent (July 2004) and operational phases (August 2005) to collect liquid and solid samples from the active evaporation and storage ponds environments (Cells 1 and 3). Cell 4, which was unused and being excavated at the times of both samplings, yielded solids accumulated through the history of that cell's use. Raffinate samples are concentrated Na-Mg-Al-Fe-SO4-NO3(-NH4) brines characterized by extreme enrichments in REE and transition elements. Ionic strengths, calculated using the Pitzer activity coefficient model varied from 25M (pH = 1 at 25°C) in Cell 1 and 12M (pH = 2.7) in Cell 3 during July 2004, to 5M (pH = 1.5) in Cell 1 and 1.2M (pH = 2.9) in Cell 3 during August 2005. At the first sampling, the dominant anion was sulfate in Cell 1 and nitrate in Cell 3. At the time of the second sampling, both cells were dominated by sulfate. During July 2004, there was significant evaporative drawdown in the ponds, resulting in 3 variably colored zones (~7m) of mineralogically complex evaporites at the cell margins. During August 2005, the operational nature of the mill and the addition of fresh water had produced high water levels in Cells 1 and 3. Evaporation crusts were recognized around the margins of the cells but they were <2m in extent. XRD analyses document the presence of boussingaultite, (NH4)2Mg(SO4)2.6H2O, which was actively precipitating from Cell 1 during 2004, tschermigite, (NH4)Al(SO4)2.12H2O, gypsum, and polymorphs of Na2SO4 including thenardite. ESEM imaging and EDS analyses of crusts reveal complex parageneses involving the above-mentioned phases and NH4-bearing metavoltine, K2Na6Fe^{+2}Fe6^{+3}(SO4)12O2.18H2O, among others. Ksp calculations and field relations are consistent with a precipitation sequence of tschermigite followed by boussingaultite and metavoltine.

Chemical characterisation of meltwater draining from Gangotri Glacier, Garhwal Himalaya, India

NASA Astrophysics Data System (ADS)

Singh, Virendra Bahadur; Ramanathan, Al; Pottakkal, Jose George; Sharma, Parmanand; Linda, Anurag; Azam, Mohd Farooq; Chatterjee, C.

2012-06-01

A detailed analytical study of major cations (Ca2 + , Mg2 + , Na + , K + ) and anions (SO4^{2-}, HCO3-, Cl - , NO3-) of meltwater draining from Gangotri Glacier was carried out to understand major ion chemistry and to get an insight into geochemical weathering processes controlling hydrochemistry of the glacier. In the meltwater, the abundance order of cations and anions varied as follows: Ca2 + > Mg2 + > K + > Na + and SO4^{2-} > HCO3- > Cl - > NO3-, respectively. Calcium and magnesium are dominant cations while sulphate and bicarbonate are dominant anions. Weathering of rocks is the dominant mechanism controlling the hydrochemistry of drainage basin. The relative high contribution of (Ca+Mg) to the total cations (TZ + ), high (Ca+Mg)/(Na+K) ratio (2.63) and low (Na+K)/TZ + ratio (0.29) indicate the dominance of carbonate weathering as a major source for dissolved ions in the glacier meltwater. Sulphide oxidation and carbonation are the main proton supplying geochemical reactions controlling the rock weathering in the study area. Statistical analysis was done to identify various factors controlling the dissolved ionic strength of Gangotri Glacier meltwater.

[Variation of atmospheric pollutants in Qinhuangdao City].

PubMed

Liu, Lu-Ning; Shen, Yu-Xuan; Xin, Jin-Yuan; Ji, Dong-Sheng; Wang, Yue-Si

2013-06-01

To illuminate the air pollution situation of the tourist city of Qinhuangdao, the atmospheric pollutants were measured from autumn 2009 to summer 2010. The results showed that the mean average concentration of NO, NO2, SO2, O3 and PM10 during the observation period reached (18 +/- 18), (45 +/- 18), (42 +/- 46), (44 +/- 25) and (128 +/- 77) microg x m(-3), respectively. The particulate matter pollution was serious, and the rate of the annual mean value exceeded the National Ambient Air Quality Standard II by 28%. The average daily concentration and average max hourly O3 concentration were (64 +/- 21)microg x m(-3) and (126 +/- 42) microg x m(-3) in summer, and the air masses from the southern ocean aggravated the O3 pollution. The concentrations of NO(x) SO2 and PM10 in the heating period were 1.5, 4.9 and 1.5 times more than those in the period without heating and the daily average concentration of SO2 and PM10 exceeded the National Ambient Air Quality Standard II by 53% and 11% in the heating period, respectively. The superimposition effect of regional transport in the Beijing-Tianjin-Hebei region and industrial area surrounding the Bohai Bay and local harbor emission led to an increase of 17% (NO(x)), 27% (SO2) and 12% (PM10), resulting in average concentrations of up to (100 +/- 49), (110 +/- 84) and (215 +/- 108) microg x m(-3) in winter. The winds from northern inland and southern ocean can effectively remove the air pollutants.

In-line electrochemical reagent generation coupled to a flow injection biamperometric system for the determination of sulfite in beverage samples.

PubMed

de Paula, Nattany T G; Barbosa, Elaine M O; da Silva, Paulo A B; de Souza, Gustavo C S; Nascimento, Valberes B; Lavorante, André F

2016-07-15

This work reports an in-line electrochemical reagent generation coupled to a flow injection biamperometric procedure for the determination of SO3(2-). The method was based on a redox reaction between the I3(-) and SO3(2-) ions, after the diffusion of SO2 through a gas diffusion chamber. Under optimum experimental conditions, a linear response ranging from 1.0 to 12.0 mg L(-1) (R=0.9999 and n=7), a detection and quantification limit estimated at 0.26 and 0.86 mg L(-1), respectively, a standard deviation relative of 0.4% (n=10) for a reference solution of 4.0 mg L(-1) SO3(2-) and sampling throughput for 40 determinations per hour were achieved. Addition and recovery tests with juice and wine samples were performed resulting in a range between 92% and 110%. There were no significant differences at a 95% confidence level in the analysis of eight samples when comparing the new method with a reference procedure. Copyright © 2016 Elsevier Ltd. All rights reserved.

The Other Chemistry of the Jovian Icy Satellites - Low Energy and Sulfurous

NASA Technical Reports Server (NTRS)

Hudson, Reggie L.; Loeffler, M. J.; Moore, M. H.

2010-01-01

Spectra of Jupiter's icy satellites reveal surfaces dominated by H2O-ice with minor amounts of SO2 and other materials. The co-existence of H2O and SO2 in surfaces exposed to jovian magnetospheric radiation suggests that sulfuric acid (H2SO4) also could be present. This was noted by Carlson et al. (1999), who supported this suggestion with assignments of near-IR bands in Europa spectra to hydrated H2SO4. Laboratory experiments since have demonstrated radiolytically-driven syntheses in S- and SO2-containing H2O-Ices (Carlson et al., 2002; Moore et al., 2006). In the Cosmic Ice Laboratory, we recently have investigated the thermal chemistry of SO2 trapped in H2O-ice. IR spectra of H2O + SO2 mixtures recorded at 10 to 230 K were used to follow low-temperature reactions in the absence of radiation effects. No SO2 reactions were found at 10 K, but warming to more-relevant Europa temperatures produced both HSO3(-) and S2O5(2-). Added NH3 shifted the product composition toward SO3(2-) and away from the other ions. We find that H2O and SO2 react to produce sulfur oxyanions, such as bisulfite, that as much as 30% of the SO2 can be consumed through this reaction, and that the products remain in the ice when the temperature is lowered, indicating that these reactions are irreversible. Our results suggest that thermally-induced reactions can alter the chemistry at and below the surfaces of the icy satellites in the jovian system.

Effects of inhalation of acidic compounds on pulmonary function in allergic adolescent subjects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koenig, J.Q.; Covert, D.S.; Pierson, W.E.

There is concern about the human health effects of inhalation of acid compounds found in urban air pollution. It was the purpose of this study to investigate three of these acid compounds, sulfur dioxide (SO/sub 2/), sulfuric acid (H/sub 2/SO/sub 4/), and nitric acid (HNO/sub 3/) in a group of allergic adolescent subjects. Subjects were exposed during rest and moderate exercise to 0.7 mumole/m/sup 3/ (68 micrograms/m/sup 3/) H/sub 2/SO/sub 4/, 4.0 mumole/m/sup 3/ (0.1 ppm) SO/sub 2/, or 2.0 mumole/m/sup 3/ (0.05 ppm) HNO/sub 3/. Pulmonary functions (FEV1, total respiratory resistance, and maximal flow) were measured before and aftermore » exposure. Preliminary analysis based on nine subjects indicates that exposure to 0.7 mumole/m/sup 3/ H/sub 2/SO/sub 4/ alone and in combination with SO/sub 2/ caused significant changes in pulmonary function, whereas exposure to air or SO/sub 2/ alone did not. FEV1 decreased an average of 6% after exposure to H/sub 2/SO/sub 4/ alone and 4% when the aerosol was combined with SO/sub 2/. The FEV1 decrease was 2% after both air and SO/sub 2/ exposures. Total respiratory resistance (RT) increased 15% after the combined H/sub 2/SO/sub 4/ exposures, 12% after H/sub 2/SO/sub 4/ alone, and 7% after exposure to air. After exposures to HNO3 alone, FEV1 decreased by 4%, and RT increased by 23%. These results are preliminary; final conclusions must wait for completion of the study.« less

Characterization of a soluble phosphatidic acid phosphatase in bitter melon (Momordica charantia).

PubMed

Cao, Heping; Sethumadhavan, Kandan; Grimm, Casey C; Ullah, Abul H J

2014-01-01

Momordica charantia is often called bitter melon, bitter gourd or bitter squash because its fruit has a bitter taste. The fruit has been widely used as vegetable and herbal medicine. Alpha-eleostearic acid is the major fatty acid in the seeds, but little is known about its biosynthesis. As an initial step towards understanding the biochemical mechanism of fatty acid accumulation in bitter melon seeds, this study focused on a soluble phosphatidic acid phosphatase (PAP, 3-sn-phosphatidate phosphohydrolase, EC 3.1.3.4) that hydrolyzes the phosphomonoester bond in phosphatidate yielding diacylglycerol and P(i). PAPs are typically categorized into two subfamilies: Mg(2+)-dependent soluble PAP and Mg(2+)-independent membrane-associated PAP. We report here the partial purification and characterization of an Mg(2+)-independent PAP activity from developing cotyledons of bitter melon. PAP protein was partially purified by successive centrifugation and UNOsphere Q and S columns from the soluble extract. PAP activity was optimized at pH 6.5 and 53-60 °C and unaffected by up to 0.3 mM MgCl2. The K(m) and Vmax values for dioleoyl-phosphatidic acid were 595.4 µM and 104.9 ηkat/mg of protein, respectively. PAP activity was inhibited by NaF, Na(3)VO(4), Triton X-100, FeSO4 and CuSO4, but stimulated by MnSO4, ZnSO4 and Co(NO3)2. In-gel activity assay and mass spectrometry showed that PAP activity was copurified with a number of other proteins. This study suggests that PAP protein is probably associated with other proteins in bitter melon seeds and that a new class of PAP exists as a soluble and Mg(2+)-independent enzyme in plants.

Deposition of Na2SO4 from salt-seeded combustion gases of a high velocity burner rig

NASA Astrophysics Data System (ADS)

Santoro, G. J.; Gokoglu, S. A.; Kohl, F. J.; Stearns, C. A.; Rosner, D. E.

The mechanism of deposition of Na2SO4 was studied under controlled laboratory conditions and the results have been compared to a recently developed comprehensive theory of vapor deposition. Thus Na2SO4, NaCl, NaNO3 and simulated sea salt solutions were injected into the combustor of a nominal Mach 0.3 burner rig burning jet fuel at constant fuel/air ratios. The deposits formed on inert collectors, rotation in the cross flow of the combustion gases, were weighed and analyzed. Collector temperature was uniform and could be varied over a large range by internal air cooling. Deposition rates and dew point temperatures were determined. Supplemental testing included droplet size measurements of the atomized salt solutions. These tests along with thermodynamic and transport calculations were utilized in the interpretation of the deposition results.

Deposition of Na2SO4 from salt-seeded combustion gases of a high velocity burner rig

NASA Technical Reports Server (NTRS)

Santoro, G. J.; Gokoglu, S. A.; Kohl, F. J.; Stearns, C. A.; Rosner, D. E.

1984-01-01

The mechanism of deposition of Na2SO4 was studied under controlled laboratory conditions and the results have been compared to a recently developed comprehensive theory of vapor deposition. Thus Na2SO4, NaCl, NaNO3 and simulated sea salt solutions were injected into the combustor of a nominal Mach 0.3 burner rig burning jet fuel at constant fuel/air ratios. The deposits formed on inert collectors, rotation in the cross flow of the combustion gases, were weighed and analyzed. Collector temperature was uniform and could be varied over a large range by internal air cooling. Deposition rates and dew point temperatures were determined. Supplemental testing included droplet size measurements of the atomized salt solutions. These tests along with thermodynamic and transport calculations were utilized in the interpretation of the deposition results.

Ammonia sources in the California South Coast Air Basin and their impact on ammonium nitrate formation

NASA Astrophysics Data System (ADS)

Nowak, J. B.; Neuman, J. A.; Bahreini, R.; Middlebrook, A. M.; Holloway, J. S.; McKeen, S. A.; Parrish, D. D.; Ryerson, T. B.; Trainer, M.

2012-04-01

Observations from the NOAA WP-3D aircraft during CalNex in May and June 2010 are used to quantify ammonia (NH3) emissions from automobiles and dairy facilities in the California South Coast Air Basin (SoCAB) and assess their impact on particulate ammonium nitrate (NH4NO3) formation. These airborne measurements in the SoCAB are used to estimate automobile NH3 emissions, 62 ± 24 metric tons day-1, and dairy facility NH3 emissions, 33 ± 16 to 176 ± 88 metric tons day-1. Emission inventories agree with the observed automobile NH3:CO emission ratio, but substantially underpredict dairy facility NH3 emissions. Conditions observed downwind of the dairy facilities were always thermodynamically favorable for NH4NO3 formation due to high NH3 mixing ratios from the concentrated sources. Although automobile emissions generated lower NH3 mixing ratios, they also can thermodynamically favor NH4NO3 formation. As an aerosol control strategy, addressing the dairy NH3 source would have the larger impact on reducing SoCAB NH4NO3 formation.

[Composition and Regional Characteristics of Atmosphere Aerosol and Its Water Soluble Ions over the Yangtze River Delta Region in a Winter Haze Period].

PubMed

Wang, Man-ting; Zhu, Bin; Wang, Hong-lei; Xue, Guo-qiang; He, Jun; Xu, Hong-hui; Cao, Jin-fei

2015-07-01

To investigate the pollution characteristics of water soluble ions in fine atmospheric particles in Yangtze River Delta during the haze period from 18th to 24th Jan 2013, a joint sampling campaign using Andersen sampler was conducted at five cities (including Nanjing, Suzhou, Hangzhou, Lin'an and Ningbo). The analysis of size distribution of these ionic species coupled with the local meteorological conditions may shed some insightful light on the haze formation mechanism in this region. The result has shown: firstly, during the observation period, when Yangtze River Delta located at high pressure or in the front of high pressure, and has a large pressure gradient, the lower atmosphere has a significant airflow divergence in favor of pollutant dispersion; while located in weak low pressure and weak high pressure, the equalizing pressure field is not favorable for pollutant dispersion, especially accompanied with lower atmosphere convergence airflow. Secondly, during the hazy period, the concentration of fine particles and total water-soluble inorganic ions (TWSS) has increased dramatically; the increasing proportions of TWSS in fine particles are: Hangzhou 0. 9%, Lin'an 4. 2%, Nanjing 8. 1%. The particle size of secondary ions of SO(4)2-, NO3-, NH4+ complies fine mode(particle size <2. 1 µm), whose peaks migrates from 0. 43-0. 65 µm to 0. 65-1. 1 µm during the observation period, the peak of particle size of Ca2+ , Mg2+ appears at 4.7-5. 8 µm, while the ions of Na+, Cl-, K+ show a bimodal distribution. Moreover, secondary inorganic ions play a significant role in the formation of haze pollution, where the concentrations of secondary inorganic ions of NH4+, SO2- and NO3 have higher increasing rates; their relative proportions of increasing from each monitoring points are: Hangzhou 3%, Lin'an 55% and Nanjing 64.9%. Finally, SO(4)2- has the highest mass contribution to SNA, up to 45% ; also, the NO-/SO- ratios in each monitoring points are always higher than a fair 0. 5, which could indicate the significant contribution of mobile source towards this particle pollution.

EnviroAtlas - Atmospheric Nitrogen and Sulfur Deposition by 12-digit HUC for the Conterminous United States (2011)

EPA Pesticide Factsheets

This EnviroAtlas dataset includes annual nitrogen and sulfur deposition within each 12-digit HUC subwatershed for the year 2011. Values are provided for total oxidized nitrogen (HNO3, NO, NO2, N2O5, NH3, HONO, PAN, organic nitrogen, and particulate NO3), oxidized nitrogen wet deposition, oxidized nitrogen dry deposition, total reduced nitrogen (NH3 and particulate NH4), reduced nitrogen dry deposition, reduced nitrogen wet deposition, total dry nitrogen deposition, total wet nitrogen deposition, total nitrogen deposition (wet+dry), total sulfur (SO2 + particulate SO4) dry deposition, total sulfur wet deposition, and total sulfur deposition. The dataset is based on output from the Community Multiscale Air Quality modeling system (CMAQ) run using the bidirectional flux option for the 12-km grid size for the US, Canada, and Mexico. The CMAQ output has been post-processed to adjust the wet deposition for errors in the location and amount of precipitation and for regional biases in the TNO3 (HNO3 + NO3), NHx (NH4 + NH3), and sulfate wet deposition. Model predicted values of dry deposition were not adjusted. This dataset was produced by the US EPA to support research and online mapping activities related to EnviroAtlas. EnviroAtlas (https://www.epa.gov/enviroatlas) allows the user to interact with a web-based, easy-to-use, mapping application to view and analyze multiple ecosystem services for the contiguous United States. The dataset is available as downloadable data

EnviroAtlas - Atmospheric Nitrogen Deposition by 12-digit HUC for the Conterminous United States (2006)

EPA Pesticide Factsheets

This EnviroAtlas dataset includes annual nitrogen and sulfur deposition within each 12-digit HUC subwatershed for the year 2006. Values are provided for total oxidized nitrogen (HNO3, NO, NO2, N2O5, NH3, HONO, PAN, organic nitrogen, and particulate NO3), oxidized nitrogen wet deposition, oxidized nitrogen dry deposition, total reduced nitrogen (NH3 and particulate NH4), reduced nitrogen dry deposition, reduced nitrogen wet deposition, total dry nitrogen deposition, total wet nitrogen deposition, total nitrogen deposition (wet+dry), total sulfur (SO2 + particulate SO4) dry deposition, total sulfur wet deposition, and total sulfur deposition. The dataset is based on output from the Community Multiscale Air Quality modeling system (CMAQ) run using the bidirectional flux option for the 12-km grid size for the US, Canada, and Mexico. The CMAQ output has been post-processed to adjust the wet deposition for errors in the location and amount of precipitation and for regional biases in the TNO3 (HNO3 + NO3), NHx (NH4 + NH3), and sulfate wet deposition. Model predicted values of dry deposition were not adjusted. This dataset was produced by the US EPA to support research and online mapping activities related to EnviroAtlas. EnviroAtlas (https://www.epa.gov/enviroatlas) allows the user to interact with a web-based, easy-to-use, mapping application to view and analyze multiple ecosystem services for the contiguous United States. The dataset is available as downloadable dat

Coadministration of Atazanavir-Ritonavir and Zinc Sulfate: Impact on Hyperbilirubinemia and Pharmacokinetics

PubMed Central

Moyle, Graeme; Else, Laura; Jackson, Akil; Back, David; Yapa, Manisha H.; Seymour, Natalia; Ringner-Nackter, Lisa; Karolia, Zeenat; Gazzard, Brian

2013-01-01

Atazanavir (ATV) causes an elevation of unconjugated hyperbilirubinemia (HBR) as a result of UDP glucuronyltransferase (UGT) 1A1 inhibition. Zinc sulfate (ZnSO4) reduces unconjugated hyperbilirubinemia in individuals with Gilbert's syndrome. We assessed the changes in total, conjugated, and unconjugated bilirubin and the effect on ATV pharmacokinetics (PK) after single and 14-day dosing of ZnSO4. HIV patients, stable on ATV/ritonavir (ATV/r)-containing regimens with a total bilirubin level of >25mmol/liter received 125 mg daily of ZnSO4 as Solvazinc tablets for 14 days. ATV/r and bilirubin concentrations were measured pre-ATV/r dose and 2, 4, 6, 8, and 24 h post-ATV/r dose; before ZnSO4 initiation (phase 1), after a single dose (phase 2) and after 14 days (phase 3). Changes in bilirubin and ATV/r concentrations in the absence or presence of ZnSO4 were evaluated by geometric mean ratios (GMRs) and 90% confidence intervals (CIs; we used phase 1 as a reference). Sixteen male patients completed the study maintaining virologic suppression; ZnSO4 was well tolerated. Statistically significant declines in total bilirubin Cmax and AUC0–24 of 16 and 17% were seen in phase2 and 20% in phase 3. Although there were no significant changes in conjugated bilirubin, unconjugated bilirubin Cmax and AUC0–24 of were lower (17 and 19%, phase 2; 20 and 23% during phase 3). The ATV GMRs (90% CI) for Ctrough, Cmax, and AUC0–24 were 0.74 (0.62 to 0.89), 0.82 (0.70 to 0.97), and 0.78 (0.70 to 0.88). Intake of ZnSO4 decreases total and unconjugated bilirubin and causes modest declines in ATV exposure. ZnSO4 supplementation may be useful in management of ATV-related HBR in selected patients. PMID:23689708

The Zn12O12 cluster-assembled nanowires as a highly sensitive and selective gas sensor for NO and NO2.

PubMed

Yong, Yongliang; Su, Xiangying; Zhou, Qingxiao; Kuang, Yanmin; Li, Xiaohong

2017-12-13

Motivated by the recent realization of cluster-assembled nanomaterials as gas sensors, first-principles calculations are carried out to explore the stability and electronic properties of Zn 12 O 12 cluster-assembled nanowires and the adsorption behaviors of environmental gases on the Zn 12 O 12 -based nanowires, including CO, NO, NO 2 , SO 2 , NH 3 , CH 4 , CO 2 , O 2 and H 2 . Our results indicate that the ultrathin Zn 12 O 12 cluster-assembled nanowires are particularly thermodynamic stable at room temperature. The CO, NO, NO 2 , SO 2 , and NH 3 molecules are all chemisorbed on the Zn 12 O 12 -based nanowires with reasonable adsorption energies, but CH 4 , CO 2 , O 2 and H 2 molecules are only physically adsorbed on the nanowire. The electronic properties of the Zn 12 O 12 -based nanowire present dramatic changes after the adsorption of the NO and NO 2 molecules, especially their electric conductivity and magnetic properties, however, the other molecules adsorption hardly change the electric conductivity of the nanowire. Meanwhile, the recovery time of the nanowire sensor at T = 300 K is estimated at 1.5 μs and 16.7 μs for NO and NO 2 molecules, respectively. Furthermore, the sensitivities of NO and NO 2 are much larger than that of the other molecules. Our results thus conclude that the Zn 12 O 12 -based nanowire is a potential candidate for gas sensors with highly sensitivity for NO and NO 2 .

Chemical Compositions of Fine Particulate Matter (PM2.5) in Handan city, China

NASA Astrophysics Data System (ADS)

Zhao, X.; Wang, L.; Zhang, P.; Yang, J.; Su, J.

2013-12-01

Handan, a industrial city located in the southern edge of Hebei Province, is listed in the top four polluted cities in China. In this study, atmospheric fine particle (PM2.5) in the urban area were collected during the period of October13 to November 21,2012, and the chemical compositions were measured for water-soluble inorganic ions(WSII) and carbonaceous species. The mean concentration of PM2.5 in that period was 112 .81 μg m-3, and in almost 70.7% of those days the PM2.5 mass concentrations exceeded the National Ambient Air Quality Standard II (NAAQS), which illustrated that the PM2.5 pollution was extremely serious in Handan. The average concentration of WSII ions in PM2.5 was 69.57 μg m-3, accounting for 61.67% of PM2.5. NO3-, SO42-, Cl- and NH4+ were four major ions, accounting for about 54.45% of PM2.5 mass. The variation of the NO3- concentrations were the largest among all the WSII ions during the sampling period. The highest daily concentration of NO3- was 66 times higher than the lowest. The ratios of NO3-/SO42- were from 0.31 to 2.25 and the average was 1.19. Carbonaceous species, OC and EC, were another important abundant composition in aerosol, accounted for 19.65% and 5.58% in PM2.5, respectively. The OC/EC ratios varied from 1.52 to 6.22 with an average of 3.44 and the estimation on a minimum OC/EC ratio showed that the secondary organic carbon (SOC) was 8.78 μg m-3.SOC concentrations during sampling period were in the range of 0.34-33.75 μg m-3, accounting for 4.81% - 65.73% of OC. High OC/EC ratios and SOC level indicated the formation of SOC was occurred during haze days. Overall, the OC/EC ratios and NO3-/SO42- indicated that vehicle exhaust and coal combustion were the main sources of pollutants in Handan.

IMPACT OF SULPHUR DIOXIDE ON THE RESPIRATORY SYSTEM OF TBILISI POPULATION.

PubMed

Vepkhvadze, N; Kiladze, N; Khorbaladze, M; Kochoradze, T; Kugoti, I

2017-04-01

The possible relationship between levels of sulphur dioxide (SO2) in the air and the rate of respiratory diseases has been studied. Results of monitoring of main contaminants of outdoor air were analyzed and they are reflected in Environmental Report 2015. Information on morbidity by respiratory system diseases of Tbilisi population is has been taken from 2011-2015 reports of the National Center of Disease Control. Identified that there is no consistent correlation between sulphur dioxide concentration in the air and respiratory system disease rates in the population, including children. Obtained data demonstrated that during the study period maximum SO2 concentration was registered in 2015 - 0,14 mg/m3 (exceeding almost 3 times maximum permissible concentration - 0,5 mg/m3) and in the same year high morbidity rates are registered (incidence -18106,08), though the lowest rates are registered in 2011 (0,09 mg/m3), when incidence of respiratory system diseases in this period (13103.2) exceeds the rates registered in 2012, 2013 and 2014 (12736.4, 11336.3, 13009.0 accordingly). There is no direct correlation between the morbidity rates of 0-15 year old children and SO2 concentration. Maximum incidence rate is registered in 2015 (48487.0) and in the same year is also registered maximum concentration of SO2 (0,14 mg/m3), whereas the lowest rate is registered in 2013 (35538,70), when SO2 concentration in 2013 is lower only by 0.02 mg/m3 compared to the concentration in 2015. Direct correlation between morbidity with asthma in children and concentration of SO2 was not identified. Prevalence of asthma is minimal in 2014 (65,4), maximal in 2012 (207,1), whereas SO2 concentration in 2014 (0,13 mg/m3) exceeds the concentration in 2012 (0,12 mg/m3). It has to be considered, that besides SO2 there are many small intensity adverse factors, which are also risk factors for development of respiratory diseases. Isolated action of these factors with certain concentrations may not demonstrate any adverse effects on human health, but the combined effect of their action is stronger and obviously will affect general health and specifically - respiratory system. Implementation of urgent measures for further improvement of their ambient air quality has been recommended, which will be the basis for minimizing of many chronic diseases.

Particulate emissions from a mid-latitude prescribed chaparral fire

NASA Technical Reports Server (NTRS)

Cofer, Wesley R., III; Levine, Joel S.; Sebacher, Daniel I.; Winstead, Edward L.; Riggin, Philip J.; Brass, James A.; Ambrosia, Vincent G.

1988-01-01

Particulate emission from a 400-acre prescribed chaparral fire in the San Dimas Experimental Forest was investigated by collecting smoke aerosol on Teflon and glass-fiber filters from a helicopter, and using SEM and EDAX to study the features of the particles. Aerosol particles ranged in size from about 0.1 to 100 microns, with carbon, oxygen, magnesium, aluminum, silicon, calcium, and iron as the primary elements. The results of ion chromatographic analysis of aerosol-particle extracts (in water-methanol) revealed the presence of significant levels of NO2(-), NO3(-), SO4(2-), Cl(-), PO4(3-), C2O4(2-), Na(+), NH4(+), and K(+). The soluble ionic portion of the aerosol was estimated to be about 2 percent by weight.

Outdoor Air Pollution and COPD-Related Emergency Department Visits, Hospital Admissions, and Mortality: A Meta-Analysis.

PubMed

DeVries, Rebecca; Kriebel, David; Sama, Susan

2017-02-01

A systematic literature review was performed to identify all peer-reviewed literature quantifying the association between short-term exposures of particulate matter <2.5 microns (PM 2.5 ), nitrogen dioxide (NO 2 ), and sulfur dioxide (SO 2 ) and COPD-related emergency department (ED) visits, hospital admissions (HA), and mortality. These results were then pooled for each pollutant through meta-analyses with a random effects model. Subgroup meta-analyses were explored to study the effects of selected lag/averaging times and health outcomes. A total of 37 studies satisfied our inclusion criteria, contributing to a total of approximately 1,115,000 COPD-related acute events (950,000 HAs, 80,000 EDs, and 130,000 deaths) to our meta-estimates. An increase in PM 2.5 of 10 ug/m 3 was associated with a 2.5% (95% CI: 1.6-3.4%) increased risk of COPD-related ED and HA, an increase of 10 ug/m 3 in NO 2 was associated with a 4.2% (2.5-6.0%) increase, and an increase of 10 ug/m 3 in SO 2 was associated with a 2.1% (0.7-3.5%) increase. The strength of these pooled effect estimates, however, varied depending on the selected lag/averaging time between exposure and outcome. Similar pooled effects were estimated for each pollutant and COPD-related mortality. These results suggest an ongoing threat to the health of COPD patients from both outdoor particulates and gaseous pollutants. Ambient outdoor concentrations of PM 2.5 , NO 2 , and SO 2 were significantly and positively associated with both COPD-related morbidity and mortality.

Determination of trace levels of uranium and thorium in high purity gadolinium sulfate using the ICP-MS with solid-phase chromatographic extraction resin

NASA Astrophysics Data System (ADS)

Ito, S.; Takaku, Y.; Ikeda, M.; Kishimoto, Y.

2017-11-01

The new Super-Kamiokande-Gadolinium (SK-Gd) project is an upgrade of the Super-Kamiokande (SK) detector. In the SK-Gd project, 0.2% Gd_2(SO_4)_3 is loaded into the 50 kton water tank of the SK. One of the main purposes of the project is to discover supernova relic neutrinos. Neutrino measurements and proton decay searches will also be performed in the SK-Gd. In order to measure solar neutrinos with a low energy threshold of ˜3.5 MeV in the SK-Gd, the main radioactive contaminations, ^{238}U and ^{232}Th, in Gd_2(SO_4)_3{\\cdot}8H_2O, should be minimized before loading. Our maximum levels for U and Th are 5 mBq (U)/kg (Gd_2(SO_4)_3{\\cdot}8H_2O) and 0.05 mBq (Th)/kg (Gd_2(SO_4)_3{\\cdot}8H_2O). In order to measure such low concentrations of U and Th in Gd_2(SO_4)_3{\\cdot}8H_2O, we developed the solid-phase extraction technique. Using this method, about 90% or more U and Th could be efficiently extracted while Gd was reduced by a factor of about 104. This allowed these radioactivity contaminations to be measured precisely as 0.04 mBq/kg (Gd_2(SO_4)_3{\\cdot}8H_2O) for U and 0.01 mBq/kg (Gd_2(SO_4)_3{\\cdot}8H_2O) for Th. We measured three pure Gd_2(SO_4)_3{\\cdot}8H_2O samples using this method and estimated that the purest one contained <0.04 mBq (U)/kg (Gd_2(SO_4)_3{\\cdot}8H_2O) and 0.06 ± 0.01 mBq (Th)/kg (Gd_2(SO_4)_3{\\cdot}8H_2O) by the ICP-MS.

Thermo and mechanoluminescence of Dy3+ activated K2Mg2(SO4)3 phosphor

NASA Astrophysics Data System (ADS)

Panigrahi, A. K.; Dhoble, S. J.; Kher, R. S.; Moharil, S. V.

2003-08-01

A solid state diffusion method for the preparation of (K2 : Dy)Mg2(SO4)3 and (K2 : Dy,P)Mg2(SO4)3 phosphors is reported. Thermoluminescence (TL) and mechanoluminescence (ML) characteristics are studied. TL, shown by the (K2 : Dy,P)Mg2(SO4)3 phosphor is 60% as intense as the conventional CaSO4 : Dy phosphor used in the TLD of ionization radiation. It has a linear TL dose response and a negligible fading. These properties of (K2 : Dy,P)Mg2(SO4)3 should be suitable in dosimetry of ionization radiation using TL technique. ML of (K2 : Dy)Mg2(SO4)3 shows one peak which has been observed in ML intensity versus time curve. The ML peak shows the recombination of electrons with free radicals (anion radicals produced by γ-irradiation) released from traps during the mechanical pressure applied on the Dy activated K2Mg2(SO4)3 phosphor. This ML mechanism is proposed for γ-irradiated sulfate based phosphors. It has been found that the total light output, i.e. ML intensity, increases with concentration of dopant, strain rate and irradiation dose of the phosphor. Mechanoluminescence and ML emission spectra of (K2 : Dy)Mg2(SO4)3 were recorded for better understanding of the ML process. The TL and ML measurements have also been performed to elucidate the mechanism of ML. Some correlation between ML and TL has also been found.

Receptor modeling of PM2.5, PM10 and TSP in different seasons and long-range transport analysis at a coastal site of Tianjin, China.

PubMed

Kong, Shaofei; Han, Bin; Bai, Zhipeng; Chen, Li; Shi, Jianwu; Xu, Zhun

2010-09-15

Atmospheric particulate matter (PM(2.5), PM(10) and TSP) were sampled synchronously during three monitoring campaigns from June 2007 to February 2008 at a coastal site in TEDA of Tianjin, China. Chemical compositions including 19 elements, 6 water-solubility ions, organic and elemental carbon were determined. principle components analysis (PCA) and chemical mass balance modeling (CMB) were applied to determine the PM sources and their contributions with the assistance of NSS SO(4)(2)(-), the mass ratios of NO(3)(-) to SO(4)(2)(-) and OC to EC. Air mass backward trajectory model was compared with source apportionment results to evaluate the origin of PM. Results showed that NSS SO(4)(2)(-) values for PM(2.5) were 2147.38, 1701.26 and 239.80 ng/m(3) in summer, autumn and winter, reflecting the influence of sources from local emissions. Most of it was below zero in summer for PM(10) indicating the influence of sea salt. The ratios of NO(3)(-) to SO(4)(2)(-) was 0.19 for PM(2.5), 0.18 for PM(10) and 0.19 for TSP in winter indicating high amounts of coal consumed for heating purpose. Higher OC/EC values (mostly larger than 2.5) demonstrated that secondary organic aerosol was abundant at this site. The major sources were construction activities, road dust, vehicle emissions, marine aerosol, metal manufacturing, secondary sulfate aerosols, soil dust, biomass burning, some pharmaceutics industries and fuel-oil combustion according to PCA. Coal combustion, marine aerosol, vehicular emission and soil dust explained 5-31%, 1-13%, 13-44% and 3-46% for PM(2.5), PM(10) and TSP, respectively. Backward trajectory analysis showed air parcels originating from sea accounted for 39% in summer, while in autumn and winter the air parcels were mainly related to continental origin. Copyright 2010 Elsevier B.V. All rights reserved.

Water-soluble part of the aerosol in the dust storm season—evidence of the mixing between mineral and pollution aerosols

NASA Astrophysics Data System (ADS)

Wang, Ying; Zhuang, Guoshun; Sun, Yele; An, Zhisheng

Six dust episodes were observed in Beijing in 2002. Both TSP (Total Suspended Particulate, particle size smaller than 100 μm) and PM 2.5 (particle size smaller than 2.5 μm) aerosol samples in these episodes were collected and their characteristics of water-soluble part were elaborated in demonstrating the mixing of mineral aerosol with pollution aerosol in the long-range transport of Asia aerosols with various sources and different paths. The dust storm peaked on 20 March, in which the highest concentrations of TSP and PM 2.5 were 10.9 and 1.4 mg m -3, respectively. The mass fraction of water-soluble part generally decreased with the increase of dust intensity. SO 42- contributed 38-70% to the total anions and Ca 2+ contributed 37-80% to the total cations, indicating that SO 42- and Ca 2+ were the most abundant anion and cation, respectively. The major ions of the water-soluble parts could be classified into three groups, i.e., the crust ions (Ca 2+, Na +, and Mg 2+), the pollution-crust ions (SO 42-, Cl -, and K +), and the pollution ions (NO 3-, NH 4+, NO 2-, and F -). Crust ions and pollution ions were the main ion fractions in super dust and non-dust days, respectively, whereas the pollution-crust ions were the main ion fractions in both dust days of various dust intensity and non-dust days, which demonstrated clearly that the mixing between mineral and pollution aerosols was ubiquitous during the dust seasons (even in the super dust storm days) although it was more obvious in those normal and weak dust episodes. The main chemical species of the water-soluble part of the aerosols were CaCO 3 in the super dust storm, CaSO 4 in the normal and the weak dust events, and NH 4NO 3 in the non-dust event days. The secondary transformation of sulfate and nitrate occurred on dust particles both during and after dust days provided the strong evidence of the mixing between mineral and pollution aerosols during the long-range transport of dust.

Removal of elemental Mercury from flue gas using wheat straw chars modified by K2FeO4 reagent.

PubMed

Zhou, Jianfei; Liu, Yangxian; Pan, Jianfeng

2017-12-01

In this article, wheat straw (WS) char, a common agricultural waste and renewable biomass, was pyrolyzed and then modified by K 2 FeO 4 reagent to develop an efficient sorbent for removal of Hg 0 from flue gas. Brunauer-Emmett-Teller, scanning electron microscopy with energy spectrum and X-ray diffraction (XRD) were employed to characterize the sorbents. The effects of K 2 FeO 4 loading, reaction temperature, Hg 0 inlet concentration and concentrations of gas mixtures O 2 , NO and SO 2 in flue gas on Hg 0 removal were investigated in a fixed-bed reactor. The results show that K 2 FeO 4 -impregnation can improve pore structure of WS char and produce new active sites, which significantly enhance Hg 0 removal. Increasing Hg 0 inlet concentration significantly decreases Hg 0 removal efficiency. O 2 in flue gas promotes Hg 0 oxidation by replenishing the oxygen groups on the surface of modified chars. The presence of NO obviously promotes Hg 0 removal since it can oxidize Hg 0 to Hg(NO 3 ) 2 . SO 2 in flue gas significantly decreases Hg 0 removal efficiency due to the competition adsorption between SO 2 and Hg 0 . The increase in reaction temperature has a dual impact on Hg 0 removal.

Anoxic nitrogen cycling in a hydrocarbon and ammonium contaminated aquifer.

PubMed

Wells, Naomi S; Kappelmeyer, Uwe; Knöller, Kay

2018-06-13

Nitrogen fate and transport through contaminated groundwater systems, where N is both ubiquitous and commonly limits pollutant attenuation, must be re-evaluated given evidence for new potential microbial N pathways. We addressed this by measuring the isotopic composition of dissolved inorganic N (DIN = NH 4 + , NO 2 - , and NO 3 - ) and N functional gene abundances (amoA, nirK, nirS, hszA) from 20 to 38 wells across an NH 4 + , hydrocarbon, and SO 4 2- contaminated aquifer. In-situ N attenuation was confirmed on three sampling dates (0, +6, +12 months) by the decreased [DIN] (4300 - 40 μM) and increased δ 15 N-DIN (5‰-33‰) over the flow path. However, the assumption of negligible N attenuation within the plume was complicated by the presence of alternative electron acceptors (SO 4 2- , Fe 3+ ), both oxidizing and reducing functional genes, and N oxides within this anoxic zone. Active plume N cycling was corroborated using an NO 2 - dual isotope based model, which found the fastest (∼10 day) NO 2 - turnover within the N and electron donor rich central plume. Findings suggest that N cycling is not always O 2 limited within chemically complex contaminated aquifers, though this cycling may recycle the N species rather than attenuate N. Copyright © 2018 Elsevier Ltd. All rights reserved.

Microbiological, physicochemical, and heavy metals assessment of groundwater quality in the Triffa plain (eastern Morocco)

NASA Astrophysics Data System (ADS)

Yahya, Hameed Saleh Ali; Jilali, Abdelhakim; Mostareh, Mohammed Mohammed Mohammed; Chafik, Zouheir; Chafi, Abdelhafid

2017-12-01

The focus of this study is the physicochemical and bacteriological characteristics of groundwater in the Triffa plain, Morocco. In total, 34 groundwater samples were analyzed for major elements (Tp, pH, EC, K+, Na+, Ca2+, Mg2+, Cl-, SO4 2-, NO3 -, NO2 -, NH4 +, H2PO4 -, CO3, and HCO3 -) and trace metal (Al, Cd, Cu, Fe, and Zn) content. The results show that the pH values range between 6.7 and 8.9, electrical conductivity ranges between 740 and 7340 µS/cm, and nitrate content ranges between 1.7 and 212 mg/l. Hydrochemical facies represented using a Piper diagram indicate an Na-K-Cl type water. All the trace metal concentrations are within the admissible standard range except for Cd. The bacteriological analysis showed that the majority of groundwater samples are contaminated. Generally, the content of total coliforms, fecal coliforms, and fecal streptococci ranged from 0 to 140, 0 to 125, and 0 to 108 CFU/100 ml, respectively. The samples are grouped according to three factors. Factor 1 shows strong positive loadings of EC, Mg, Cl, Na and K with 51.91% of total variance (TV); factor 2 shows strong negative loadings of NO3, SO4 and Ca with 17.98% of TV; and factor 3 shows strong negative loading of HCO3 with 15.56 of TV. We conclude that the quality of this groundwater is suitable for irrigation and domestic use (cleaning house, ect).

Associations of gestational and early life exposures to ambient air pollution with childhood atopic eczema in Shanghai, China.

PubMed

Liu, Wei; Cai, Jiao; Huang, Chen; Hu, Yu; Fu, Qingyan; Zou, Zhijun; Sun, Chanjuan; Shen, Li; Wang, Xueying; Pan, Jun; Huang, Yanmin; Chang, Jing; Zhao, Zhuohui; Sun, Yuexia; Sundell, Jan

2016-12-01

Whether ambient air pollution is associated with childhood atopic eczema is controversial. In this paper, we selected 3358 preschool children who had not altered residences since pregnancy from a cross-sectional study during 2011-2012 in Shanghai, China, and obtained parent-reported data regarding childhood atopic eczema using an improved ISAAC questionnaire. We recorded daily concentrations of SO 2 , NO 2 , and PM 10 throughout the child's lifetime (2006-2012), and calculated period-averaged concentrations for each district where the child lived to represent the child's exposure levels of these pollutants during different periods. In the multiple logistic regression analyses adjusted for potential confounders as well as for the other pollutants in the same periods, childhood atopic eczema was significantly associated with increments of NO 2 in the approximate interquartile range (20μg/m 3 ) during gestational period (adjusted OR, 95% CI for eczema lifetime-ever: 1.80, 1.29-2.49; for eczema in the year prior to the survey: 2.32, 1.57-3.43) and during the first year of life (2.00, 1.40-2.84; 2.16, 1.43-3.28). Exposure to elevated NO 2 in the first two years, three years and total lifetime, as well as exposure to mixtures containing NO 2 in each of these periods, were consistently associated with increased likelihood of childhood eczema. The highest odds ratios were found between exposure to a mixture of SO 2 and NO 2 during total lifetime (increment: 35μg/m 3 ) and childhood eczema (adjusted OR, 95% CI: 2.80, 1.75-4.48; 3.50, 1.98-6.19). No significant associations were found between childhood eczema and ambient SO 2 and PM 10 individually or in mixtures. This study indicates that gestational and lifetime exposures to ambient NO 2 are risk factors for atopic eczema in childhood. Exposure to ambient SO 2 and PM 10 may enhance the effect of NO 2 exposure on childhood eczema. Copyright © 2016 Elsevier B.V. All rights reserved.

Hydro-chemical Survey and Quantifying Spatial Variations of Groundwater Quality in Dwarka, Sub-city of Delhi, India

NASA Astrophysics Data System (ADS)

Rawat, Kishan Singh; Tripathi, Vinod Kumar

2015-06-01

Hydrological and geological aspect of the region play vital role for water resources utilization and development. Protection and management of groundwater resources are possible with the study of spatio-temporal water quality parameters. The study was undertaken to assess the deterioration in groundwater quality, through systematic sampling during post monsoon seasons of the year 2008 by collecting water samples from thirty bore wells located in Dwarka, sub-city of Delhi, India. The average concentrations of groundwater quality parameters namely Calcium (Ca2+), Magnesium (Mg2+), Nitrate (NO3 -), Chloride (Cl-), sulphate (SO4 2-), total hardness (TH), total dissolved solids (TDS), and electrical conductivity were 300, 178, 26.5, 301, 103, 483, 1042 mg/l and 1909 μS/cm respectively. Estimated physico-chemical parameters revealed that 7 % of the groundwater samples shown nitrate concentrations higher than safe limit prescribed by World Health Organization (WHO). Groundwater quality the in study region was poor due to come out result that NO3 - concentration exceeding the threshold value of 50 mg/l, and main cause is disposal of sewage and animal wastes to Najafgarh drain. Dominant cations are Mg2+, Ca2+ and anions are SO4 2- and Cl-. The abundance of the major ions in groundwater is in the order: Ca2+ > Mg2+ and Cl- > SO4 2- > NO3. TH have strong correlation with Ca2+ (r = 0.81), Mg2+ (r = 0.82), Cl- (r = 0.86) but poor correlation with TDS (r = 0.52). Knowledge of correlation values between water quality parameters is helpful to take decision of appropriate management strategy for controlling groundwater pollution.

ELECTROLYTIC CORROSION OF GOLD AND THE FORMATION OF Au//2(SO//4)//3 IN CONCENTRATED SULFURIC ACID.

USGS Publications Warehouse

Senftle, Frank E.; Wright, Donald B.

1985-01-01

The authors have examined the direct anodic oxidation of gold in concentrated H//2SO//4 to more fully understand the chemical reactions. Au//2(SO//4)//3 is unstable and cannot be isolated for chemical analysis, but our experiments are consistent with the formation of Au//2(SO//4)//3 in concentrated H//2SO//4, in which it is stable. Equations describing chemical reactions which are compatible with the experimental data are presented.

Intravenous magnesium sulfate for vaso-occlusive episodes in sickle cell disease.

PubMed

Goldman, Ran D; Mounstephen, William; Kirby-Allen, Melanie; Friedman, Jeremy N

2013-12-01

Vaso-occlusive episodes (VOEs) are the most common complication of sickle cell disease in children. Treatment with magnesium seems to improve cellular hydration and may result in reduced vaso-occlusion. This study aimed to determine if intravenous (IV) magnesium sulfate (MgSO4) reduces length of stay (LOS) in hospital, pain scores, and cumulative analgesia when compared with placebo. Randomized, double-blind, placebo-controlled trial in children aged 4 to 18 years requiring admission to hospital with a sickle cell disease VOE requiring IV analgesia. Participating children received IV MgSO4 (100 mg/kg) every 8 hours or placebo in addition to standard therapy. We used a t test or Mann-Whitney test (continuous variables), Fisher's exact test, or χ2 test (frequencies). P values were considered significant if <.05, and 95% confidence intervals were calculated for the difference between groups. One hundred six children were randomly assigned to the study, and 104 were included. Fifty-one (49%) received MgSO4. Children's mean age was 12.4 years (range: 4-18 years; SD: 3.8 years), and 56 (54%) were females. There was no significant difference in the primary outcome measure, LOS in hospital, with a mean of 132.6 and 117.7 hours in the MgSO4 and placebo groups, respectively (P = .41). There was no significant difference between groups for the secondary outcomes of mean pain scores (4.9 ± 2.6 vs 4.8 ± 2.6, respectively; P = .92) or analgesic requirements (continuous morphine infusion [P = .928], boluses of IV morphine [P = .82], acetaminophen [P = .34], ibuprofen [P = .15], naproxen [P = .10]). Only minor adverse events were recorded in both groups. Pain at the infusion site was more common in the MgSO4 group. IV MgSO4 was well tolerated but had no effect on the LOS in hospital, pain scores, or cumulative analgesia use in admitted children with a VOE.

Synthetic, Infrared, 1H and 13C NMR Spectral Studies on N-(2-/3-Substituted Phenyl)-4-Substituted Benzenesulphonamides, 4-X'C6H4SO2NH(2-/3-XC6H4), where X' = H, CH3, C2H5, F, Cl or Br, and X = CH3 or Cl

NASA Astrophysics Data System (ADS)

Gowda, B. Thimme; Shetty, Mahesha; Jayalakshmi, K. L.

2005-02-01

Twenty three N-(2-/3-substituted phenyl)-4-substituted benzenesulphonamides of the general formula, 4-X'C6H4SO2NH(2-/3-XC6H4), where X' = H, CH3, C2H5, F, Cl or Br and X = CH3 or Cl have been prepared and characterized, and their infrared spectra in the solid state, 1H and 13C NMR spectra in solution were studied. The N-H stretching vibrations, νN-H, absorb in the range 3285 - 3199 cm-1, while the asymmetric and symmetric SO2 vibrations vary in the ranges 1376 - 1309 cm-1 and 1177 - 1148 cm-1, respectively. The S-N and C-N stretching vibrations absorb in the ranges 945 - 893 cm-1 and 1304 - 1168 cm-1, respectively. The compounds do not exhibit particular trends in the variation of these frequencies on substitution either at ortho or meta positions with either a methyl group or Cl. The observed 1H and 13C chemical shifts of are assigned to protons and carbons of the two benzene rings. Incremental shifts of the ring protons and carbons due to -SO2NH(2-/3-XC6H4) groups in C6H5SO2NH(2-/3-XC6H4), and 4- X'C6H4SO2- and 4-X'C6H4SO2NH- groups in 4-X'C6H4SO2NH(C6H5) are computed and employed to calculate the chemical shifts of the ring protons and carbons in the substituted compounds, 4-X'C6H4SO2NH(2-/3-XC6H4). The computed values agree well with the observed chemical shifts.

Solid state reactions of CeO 2, PuO 2, (U,Ce)O 2 and (U,Pu)O 2 with K 2S 2O 8

NASA Astrophysics Data System (ADS)

Keskar, Meera; Kasar, U. M.; Mudher, K. D. Singh; Venugopal, V.

2004-09-01

Solid state reactions of CeO 2, PuO 2 and mixed oxides (U,Ce)O 2 and (U,Pu)O 2 containing different mol.% of Ce and Pu, were carried out with K 2S 2O 8 at different temperatures to identify the formation of various products and to investigate their dissolution behaviour. X-ray, chemical and thermal analysis methods were used to characterise the products formed at various temperatures. The products obtained by heating two moles of K 2S 2O 8 with one mole each of CeO 2, PuO 2, (U,Ce)O 2 and (U,Pu)O 2 at 400 °C were identified as K 4Ce(SO 4) 4, K 4Pu(SO 4) 4, K 4(U,Ce)(SO 4) 4 and K 4(U,Pu)(SO 4) 4, respectively. K 4Ce(SO 4) 4 further decomposed to form K 4Ce(SO 4) 3.5 at 600 °C and mixture of K 2SO 4 and CeO 2 at 950 °C. Thus the products formed during the reaction of 2K 2S 2O 8 + CeO 2 show that cerium undergoes changes in oxidation state from +4 to +3 and again to +4. XRD data of K 4Ce(SO 4) 4 and K 4Ce(SO 4) 3.5 were indexed on triclinic and monoclinic system, respectively. PuO 2 + 2K 2S 2O 8 reacts at 400 °C to form K 4Pu(SO 4) 4 which was stable upto 750 °C and further decomposes to form K 2SO 4 + PuO 2 at 1000 °C. The products formed at 400 °C during the reactions of the oxides and mixed oxides were found to be readily soluble in 1-2 M HNO 3.

Chemical modeling for precipitation from hypersaline hydrofracturing brines.

PubMed

Zermeno-Motante, Maria I; Nieto-Delgado, Cesar; Cannon, Fred S; Cash, Colin C; Wunz, Christopher C

2016-10-15

Hypersaline hydrofracturing brines host very high salt concentrations, as high as 120,000-330,000 mg/L total dissolved solids (TDS), corresponding to ionic strengths of 2.1-5.7 mol/kg. This is 4-10 times higher than for ocean water. At such high ionic strengths, the conventional equations for computing activity coefficients no longer apply; and the complex ion-interactive Pitzer model must be invoked. The authors herein have used the Pitzer-based PHREEQC computer program to compute the appropriate activity coefficients when forming such precipitates as BaSO4, CaSO4, MgSO4, SrSO4, CaCO3, SrCO3, and BaCO3 in hydrofracturing waters. The divalent cation activity coefficients (γM) were computed in the 0.1 to 0.2 range at 2.1 mol/kg ionic strength, then by 5.7 mol/kg ionic strength, they rose to 0.2 for Ba(2+), 0.6 for Sr(2+), 0.8 for Ca(2+), and 2.1 for Mg(2+). Concurrently, the [Formula: see text] was 0.02-0.03; and [Formula: see text] was 0.01-0.02. While employing these Pitzer-derived activity coefficients, the authors then used the PHREEQC model to characterize precipitation of several of these sulfates and carbonates from actual hydrofracturing waters. Modeled precipitation matched quite well with actual laboratory experiments and full-scale operations. Also, the authors found that SrSO4 effectively co-precipitated radium from hydrofracturing brines, as discerned when monitoring (228)Ra and other beta-emitting species via liquid scintillation; and also when monitoring gamma emissions from (226)Ra. Copyright © 2016 Elsevier Ltd. All rights reserved.

Global SO(3) x SO(3) x U(1) symmetry of the Hubbard model on bipartite lattices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carmelo, J.M.P., E-mail: carmelo@fisica.uminho.p; Ostlund, Stellan; Sampaio, M.J.

2010-08-15

In this paper the global symmetry of the Hubbard model on a bipartite lattice is found to be larger than SO(4). The model is one of the most studied many-particle quantum problems, yet except in one dimension it has no exact solution, so that there remain many open questions about its properties. Symmetry plays an important role in physics and often can be used to extract useful information on unsolved non-perturbative quantum problems. Specifically, here it is found that for on-site interaction U {ne} 0 the local SU(2) x SU(2) x U(1) gauge symmetry of the Hubbard model on amore » bipartite lattice with N{sub a}{sup D} sites and vanishing transfer integral t = 0 can be lifted to a global [SU(2) x SU(2) x U(1)]/Z{sub 2}{sup 2} = SO(3) x SO(3) x U(1) symmetry in the presence of the kinetic-energy hopping term of the Hamiltonian with t > 0. (Examples of a bipartite lattice are the D-dimensional cubic lattices of lattice constant a and edge length L = N{sub a}a for which D = 1, 2, 3,... in the number N{sub a}{sup D} of sites.) The generator of the new found hidden independent charge global U(1) symmetry, which is not related to the ordinary U(1) gauge subgroup of electromagnetism, is one half the rotated-electron number of singly occupied sites operator. Although addition of chemical-potential and magnetic-field operator terms to the model Hamiltonian lowers its symmetry, such terms commute with it. Therefore, its 4{sup N}{sub a}{sup D} energy eigenstates refer to representations of the new found global [SU(2) x SU(2) x U(1)]/Z{sub 2}{sup 2} = SO(3) x SO(3) x U(1) symmetry. Consistently, we find that for the Hubbard model on a bipartite lattice the number of independent representations of the group SO(3) x SO(3) x U(1) equals the Hilbert-space dimension 4{sup N}{sub a}{sup D}. It is confirmed elsewhere that the new found symmetry has important physical consequences.« less

A naphthalene exciplex based Al3+ selective on-type fluorescent probe for living cells at the physiological pH range: experimental and computational studies.

PubMed

Banerjee, Arnab; Sahana, Animesh; Das, Sudipta; Lohar, Sisir; Guha, Subarna; Sarkar, Bidisha; Mukhopadhyay, Subhra Kanti; Mukherjee, Asok K; Das, Debasis

2012-05-07

2-((Naphthalen-6-yl)methylthio)ethanol (HL) was prepared by one pot synthesis using 2-mercaptoethanol and 2-bromomethylnaphthalene. It was found to be a highly selective fluorescent sensor for Al(3+) in the physiological pH (pH 7.0-8.0). It could sense Al(3+) bound to cells through fluorescence microscopy. Metal ions like Mn(2+), Fe(3+), Co(2+), Ni(2+), Cu(2+), Zn(2+), Ag(+), Cd(2+), Hg(2+), Cr(3+) and Pb(2+) did not interfere. No interference was also observed with anions like Cl(-), Br(-), F(-), SO(4)(2-), NO(3)(-), CO(3)(2-), HPO(4)(2-) and SCN(-). Experimentally observed structural and spectroscopic features of HL and its Al(3+) complex have been substantiated by computational calculations using density functional theory (DFT) and time dependent density functional theory (TDDFT).

Chemistry of selected high-elevation lakes in seven national parks in the western United States

USGS Publications Warehouse

Clow, David W.; Striegl, Robert G.; Nanus, Leora; Mast, M. Alisa; Campbell, Donald H.; Krabbenhoft, David P.

2002-01-01

A chemical survey of 69 high-altitude lakes in seven national parks in the western United States was conducted during the fallof 1999; the lakes were previously sampled during the fall of 1985, as part of the Western Lake Survey. Lakes in parks in the Sierra/southern Cascades (Lassen Volcanic, Yosemite, Sequoia/Kings Canyon National Parks) and in the southern RockyMountains (Rocky Mountain National Park) were very dilute; medianspecific conductance ranged from 4.4 to 12.2 μS cm-1 andmedian alkalinity concentrations ranged from 32.2 to 72.9 μeqL-1. Specific conductances and alkalinity concentrations were substantially higher in lakes in the central and northernRocky Mountains parks (Grand Teton, Yellowstone, and GlacierNational Parks), probably due to the prevalence of more reactivebedrock types. Regional patterns in lake concentrations of NO3 and SO4 were similar to regional patterns in NO3 and SO4 concentrations in precipitation, suggestingthat the lakes are showing a response to atmospheric deposition.Concentrations of NO3 were particularly high in Rocky Mountain National Park, where some ecosystems appear to be undergoing nitrogen saturation.

Porous sulfated metal oxide SO4 2-/Fe2O3 as an anode material for Li-ion batteries with enhanced electrochemical performance

NASA Astrophysics Data System (ADS)

Li, Zhen; Lv, Qianqian; Huang, Xiaoxiong; Tan, Yueyue; Tang, Bohejin

2017-01-01

Sulfated metal oxide SO4 2-/Fe2O3 was prepared by a novel facile sol-gel method combined with a subsequent heating treatment process. The as-synthesized products were analyzed by XRD, FTIR, and FE-SEM. Compared with the unsulfated Fe2O3, the agglomeration of particles has been alleviated after the incorporation of SO4 2-. Interestingly, the primary particle size of the SO4 2-/Fe2O3 (about 5 nm) is similar to its normal counterparts even after the calcination treatment. More importantly, SO4 2-/Fe2O3 exhibits a porous architecture, which is an intriguing feature for electrode materials. When used as anode materials in Li-ion batteries, SO4 2-/Fe2O3 delivered a higher reversible discharge capacity (992 mAh g-1), with smaller charge transfer resistance, excellent rate performance, and better cycling stability than normal Fe2O3. We believed that the presence of SO4 2- and porous architecture should be responsible for the enhanced electrochemical performance, which could provide more continuous and accessible conductive paths for Li+ and electrons.

Thermochemical production of hydrogen

DOEpatents

Dreyfuss, Robert M.

1976-07-13

A thermochemical reaction cycle for the generation of hydrogen from water comprising the following sequence of reactions wherein M represents a metal and Z represents a metalloid selected from the arsenic-antimony-bismuth and selenium-tellurium subgroups of the periodic system: 2MO + Z + SO.sub.2 .fwdarw. MZ + MSO.sub.4 (1) mz + h.sub.2 so.sub.4 .fwdarw. mso.sub.4 + h.sub.2 z (2) 2mso.sub.4 .fwdarw. 2mo + so.sub.2 + so.sub.3 + 1/20.sub.2 (3) h.sub.2 z .fwdarw. z + h.sub.2 (4) h.sub.2 o + so.sub.3 .fwdarw. h.sub.2 so.sub.4 (5) the net reaction is the decomposition of water into hydrogen and oxygen.

Aqueous aerosol may build up large upper tropospheric ice supersaturation

NASA Astrophysics Data System (ADS)

Bogdan, Anatoli; Molina, Mario J.

2010-05-01

Keywords: ice supersaturation, upper tropospheric cirrus clouds, freezing of aqueous aerosol. Observations often reveal enhanced and persistent upper tropospheric (UT) ice supersaturation, Si up to 100%, independently of whether cirrus ice clouds are present or not (Krämer et al., 2009; Lawson et al., 2008). However, a water activity criterion (WAC) (Koop et al., 2000) does not allow the formation of Si > ~67% by the homogeneous freezing of aqueous droplets even at the lowest atmospheric temperature of ~185 K. For aqueous aerosol the WAC predicts the existence of a so called homogeneous ice nucleation threshold which, being expressed as Si, is between ~52 and 67% in the temperature range of ~220 - 185 K. The nature of the formation of large Si remains unclear. Since water vapor is the dominant greenhouse gas it is important to know the nature of the accumulation and persistence of water vapor in the UT. We studied the freezing behavior of micrometer-scaled 3-, 4-, and 5-component droplets, which contain different weight fractions of H2O, H2SO4, HNO3, (NH4)2SO4, (NH4)HSO4, NH4NO3, and (NH4)3H(SO4)2. The study was performed between 133 and 278 K at cooling rates of 3, 0.1, and 0.05 K/min using differential scanning calorimetry (DSC) (Bogdan and Molina, 2010). The cooling rates of 0.1 and 0.05 K/min (6 and 3 K/h) are similar to the smallest reported synoptic temperature change of ~2 K/h (Carslaw et al., 1998). Using the measured freezing temperature of ice, Ti, and the thermodynamic E-AIM model of the system of H+ - NH4+ - SO42-- NO3-- H2O (Clegg et al., 1998), we calculated the corresponding clear-sky Si which would be built up immediately prior to the formation of ice cirrus clouds by the homogeneous freezing of aqueous aerosol of similar composition. We found that our calculated values of Si are both larger and smaller than the homogeneous ice nucleation threshold. For example, for the droplets of compositions of 15/10 and 20/10 wt % (NH4)3H(SO4)2/H2SO4, which freeze at 194 and 186 K, respectively, the calculated clear-sky Si can exceed 80%. Although our Si values are smaller than the largest observed value of Si ≈ 100%, they are nevertheless larger than the Si ≈ 67% predicted by the WAC at 185 K. Our results can give an impetus for the study of whether multi-component aqueous aerosol, which besides inorganic components also contains organics, may produce the observed Si ≈ 100%. Krämer, M., Schiller, C., Afchine, A., Bauer, R., Gensch, I., Mangold, A.., Schlicht, S., Spelten, N., Sitnikov, N., Borrmann, S., de Reus, M., Spichtinger, P. (2009), Atmos. Chem. Phys. 9, 3505. Lawson, R. P., Pilson, B., Baker, B., Mo, Q., Jensen, E., Pfister, L., Bui, P. (2008), Atmos. Chem. Phys. 8, 1609. Koop, T., Luo, B., Tsias, A., Peter, T. (2000), Nature, 406, 611. Bogdan, A. and Moilna, M. J. (2010), J. Phys. Chem. A (Published online: 5 February). Carslaw, K. S., Wirth, M., Tsias, A., Luo, B. P., Dörnbrack, A., Leutbecher, M., Volkert, H., Renger, W., Bacmeister, J. T., Peter, T. (1998), J. Geophys. Res. 103, 5785. Clegg, S. L., Brimblecombe, P., Wexler, A. S. (1998), J. Phys. Chem. A 102, 2137.

Application of an online ion chromatography-based instrument ...

EPA Pesticide Factsheets

In North America, the dry component of total nitrogen and sulfur deposition remains uncertain due to a lack of measurements of sufficient chemical speciation and temporal extent to develop complete annual mass budgets or of sufficient process level detail to improve current air-surface exchange models. Over the past decade, significant advances have been made in the development of continuous chemical measurement techniques with sufficient sensitivity and temporal resolution to directly quantify air-surface exchange of nitrogen and sulfur compounds. However, their applicability is generally restricted to only one or a few of the compounds within the deposition budget. We characterize for the first time the performance of the Monitor for AeRosols and GAses in ambient air (MARGA), an on-line ion chromatography-based analyzer, as applied for air-surface exchange measurements of HNO3, NH3, NH4+, NO3-, SO2 and SO42-. Analytical accuracy and precision are assessed under field conditions and total uncertainty of fluxes measured by the aerodynamic gradient method are assessed for a representative 3-week period in the fall of 2012. During this period, percentages of hourly chemical gradients larger than the corresponding gradient detection limit were 86%, 55%, 81%, 74%, 77%, and 71% for NH3, NH4+, HNO3, NO3-, SO2, and SO42-, respectively. As expected, percentages were lowest for aerosol species, owing to their relatively low deposition velocities and correspondingly sma

Photochemistry of matrix isolated (trifluoromethyl)sulfonyl azide, CF₃SO₂N₃.

PubMed

Zeng, Xiaoqing; Beckers, Helmut; Willner, Helge; Neuhaus, Patrik; Grote, Dirk; Sander, Wolfram

2015-03-19

The photochemistry of matrix isolated (trifluoromethylsulfonyl) azide, CF3SO2N3, has been studied at low temperatures. Upon ArF laser irradiation (λ = 193 nm), the azide eliminates N2 and furnishes triplet [(trifluoromethyl)sulfonyl]nitrene, CF3SO2N, which has been characterized by IR and EPR spectroscopy. Upon subsequent UV light irradiation (λ = 260-400 nm) the nitrene converts to CF3N═SO2 and CF3S(O)NO through a Curtius-type rearrangement. Further two new species CF2N═SO2F and FSNO were identified together with CF2NF, SO2, F2CO, CF3NO, and SO as side products. In addition, triplet nitrene CF3N was detected by its EPR and IR spectra. The complex stepwise photodecomposition of matrix isolated CF3SO2N3 is discussed in terms of the observed photolysis products and quantum chemical calculations.

21 CFR 184.1143 - Ammonium sulfate.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Ammonium sulfate. 184.1143 Section 184.1143 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DIRECT... GRAS § 184.1143 Ammonium sulfate. (a) Ammonium sulfate ((NH4)2SO4, CAS Reg. No. 7783-20-2) occurs...

Carbon catalyzed SO2 oxidation by NO2 and O3

NASA Technical Reports Server (NTRS)

Cofer, W. R., III; Schryer, D. R.; Rogowski, R. S.

1982-01-01

The oxidation of SO2 to sulfate on carbon particles by trace quantities of NO2 and O3 was studied. Particulate carbon black was either: (1) directly exposed on the pan of a microbalance to various humidified mixtures of SO2 and oxidant gas and the resultant weight gains monitored, or (2) the gas mixtures were bubbled through aqueous suspensions of carbon black and pure water blanks. In each set of experiments the run times were varied appropriately and the yields of sulfate were determined analytically. Conversion of SO2 to sulfate was thus characterized as a function of exposure time and of oxidant gas. Carbon black was determined to be an excellent catalyst for SO2 oxidation to sulfate by both NO2 and O3. No saturation effects were observed in either experimental approach. Conversions of SO2 to sulfate did not appear pH dependent.

Interactions of methylamine and ammonia with atmospheric nucleation precursor H{sub 2}SO{sub 4} and common organic acids: Thermodynamics and atmospheric implications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Y.; Jiang, L.; Bai, Z.

Interactions of the two common atmospheric bases, ammonia (NH{sub 3}) and methylamine MA (CH{sub 3}NH{sub 2}), which are considered to be important stabilizers of binary clusters in the Earth’s atmosphere, with H{sub 2}SO{sub 4}, the key atmospheric precursor, and 14 common atmospheric organic acids (COA) (formic (CH{sub 2}O{sub 2}), acetic (C{sub 2}H{sub 4}O{sub 2}), oxalic (C{sub 2}H{sub 2}O{sub 4}), malonic (C{sub 3}H{sub 4}O{sub 4}), succinic (C{sub 4}H{sub 6}O{sub 4}), glutaric acid (C{sub 5}H{sub 8}O{sub 4}), adipic (C{sub 6}H{sub 10}O{sub 4}), benzoic (C{sub 6}H{sub 5}COOH), phenylacetic (C{sub 6}H{sub 5}CH{sub 2}COOH), pyruvic (C{sub 3}H{sub 4}O{sub 3}), maleic acid (C{sub 4}H{sub 4}O{sub 4}),more » malic (C{sub 4}H{sub 6}O{sub 5}), tartaric (C{sub 4}H{sub 6}O{sub 6}) and pinonic acid (C{sub 10}H{sub 16}O{sub 3})) have been studied using the composite high-accuracy G3MP2 method. The thermodynamic stability of mixed (COA) (H{sub 2}SO{sub 4}), (COA)(B1) and (COA)(B2) dimers and (COA) (H{sub 2}SO{sub 4}) (B1) and (COA) (H{sub 2}SO{sub 4}) (B1) trimers, where B1 and B2 represent methylamine (CH{sub 3}NH{sub 2}) and ammonia (NH{sub 3}), respectively, have been investigated and their impacts on the thermodynamic stability of clusters containing H{sub 2}SO{sub 4} have been analyzed. It has been shown that in many cases the interactions of H{sub 2}SO{sub 4} with COA, ammonia and methylamine lead to the formation of heteromolecular dimers and trimers, which are certainly more stable than (H{sub 2}SO{sub 4}){sub 2} and (H{sub 2}SO{sub 4}){sub 3}. It has also been found that free energies of (COA) (H{sub 2}SO{sub 4})+ CH{sub 3}NH{sub 2}⇔(COA) (H{sub 2}SO{sub 4})(CH{sub 3}NH{sub 2}) reactions exceed 10-15 kcal mol{sup −1}. This is a clear indication that mixed trimers composed of COA, H{sub 2}SO{sub 4} and methylamine are very stable and can thus serve as possible nucleation sites. The present study leads us to conclude that the interactions of COA coexisting with H{sub 2}SO{sub 4} and common atmospheric bases in the Earth’s atmosphere may be an important factor affecting the stability of nucleating sulfuric acid clusters and that the impacts of COA on atmospheric nucleation should be studied in further details.« less

Efficient degradation of TCE in groundwater using Pd and electro-generated H2 and O2: a shift in pathway from hydrodechlorination to oxidation in the presence of ferrous ions.

PubMed

Yuan, Songhu; Mao, Xuhui; Alshawabkeh, Akram N

2012-03-20

Degradation of trichloroethylene (TCE) in simulated groundwater by Pd and electro-generated H(2) and O(2) is investigated in the absence and presence of Fe(II). In the absence of Fe(II), hydrodechlorination dominates TCE degradation, with accumulation of H(2)O(2) up to 17 mg/L. Under weak acidity, low concentrations of oxidizing •OH radicals are detected due to decomposition of H(2)O(2), slightly contributing to TCE degradation via oxidation. In the presence of Fe(II), the degradation efficiency of TCE at 396 μM improves to 94.9% within 80 min. The product distribution proves that the degradation pathway shifts from 79% hydrodechlorination in the absence of Fe(II) to 84% •OH oxidation in the presence of Fe(II). TCE degradation follows zeroth-order kinetics with rate constants increasing from 2.0 to 4.6 μM/min with increasing initial Fe(II) concentration from 0 to 27.3 mg/L at pH 4. A good correlation between TCE degradation rate constants and •OH generation rate constants confirms that •OH is the predominant reactive species for TCE oxidation. Presence of 10 mM Na(2)SO(4), NaCl, NaNO(3), NaHCO(3), K(2)SO(4), CaSO(4), and MgSO(4) does not significantly influence degradation, but sulfite and sulfide greatly enhance and slightly suppress degradation, respectively. A novel Pd-based electrochemical process is proposed for groundwater remediation.

Efficient Degradation of TCE in Groundwater Using Pd and Electro-generated H2 and O2: A Shift in Pathway from Hydrodechlorination to Oxidation in the Presence of Ferrous Ions

PubMed Central

Yuan, Songhu; Mao, Xuhui; Alshawabkeh, Akram N.

2012-01-01

Degradation of trichloroethylene (TCE) in simulated groundwater by Pd and electro-generated H2 and O2 is investigated in the absence and presence of Fe(II). In the absence of Fe(II), hydrodechlorination dominates TCE degradation, with accumulation of H2O2 up to 17 mg/L. Under weak acidity, low concentrations of oxidizing •OH radical are detected due to decomposition of H2O2, slightly contributing to TCE degradation via oxidation. In the presence of Fe(II), the degradation efficiency of TCE at 396 μM improves to 94.9% within 80 min. The product distribution proves that the degradation pathway shifts from 79% hydrodechlorination in the absence of Fe(II) to 84% •OH oxidation in the presence of Fe(II). TCE degradation follows zeroth-order kinetics with rate constants increasing from 2.0 to 4.6 μM/min with increasing initial Fe(II) concentration from 0 to 27.3 mg/L at pH 4. A good correlation between TCE degradation rate constants and •OH generation rate constants confirms that •OH is the predominant reactive species for TCE oxidation. Presence of 10 mM Na2SO4, NaCl, NaNO3, NaHCO3, K2SO4, CaSO4 and MgSO4 does not significantly influence degradation, but sulfite and sulfide greatly enhance and slightly suppresses degradation, respectively. A novel Pd-based electrochemical process is proposed for groundwater remediation. PMID:22315993

Methanesulfonates of high-valent metals: syntheses and structural features of MoO2(CH3SO3)2, UO2(CH3SO3)2, ReO3(CH3SO3), VO(CH3SO3)2, and V2O3(CH3SO3)4 and their thermal decomposition under N2 and O2 atmosphere.

PubMed

Betke, Ulf; Neuschulz, Kai; Wickleder, Mathias S

2011-11-04

Oxide methanesulfonates of Mo, U, Re, and V have been prepared by reaction of MoO(3), UO(2)(CH(3)COO)(2)·2H(2)O, Re(2)O(7)(H(2)O)(2), and V(2)O(5) with CH(3)SO(3)H or mixtures thereof with its anhydride. These compounds are the first examples of solvent-free oxide methanesulfonates of these elements. MoO(2)(CH(3)SO(3))(2) (Pbca, a=1487.05(4), b=752.55(2), c=1549.61(5) pm, V=1.73414(9) nm(3), Z=8) contains [MoO(2)] moieties connected by [CH(3)SO(3)] ions to form layers parallel to (100). UO(2)(CH(3)SO(3))(2) (P2(1)/c, a=1320.4(1), b=1014.41(6), c=1533.7(1) pm, β=112.80(1)°, V=1.8937(3) nm(3), Z=8) consists of linear UO(2)(2+) ions coordinated by five [CH(3)SO(3)] ions, forming a layer structure. VO(CH(3)SO(3))(2) (P2(1)/c, a=1136.5(1), b=869.87(7), c=915.5(1) pm, β=113.66(1)°, V=0.8290(2) nm(3), Z=4) contains [VO] units connected by methanesulfonate anions to form corrugated layers parallel to (100). In ReO(3)(CH(3)SO(3)) (P1, a=574.0(1), b=1279.6(3), c=1641.9(3) pm, α=102.08(2), β=96.11(2), γ=99.04(2)°, V=1.1523(4) nm(3), Z=8) a chain structure exhibiting infinite O-[ReO(2)]-O-[ReO(2)]-O chains is formed. Each [ReO(2)]-O-[ReO(2)] unit is coordinated by two bidentate [CH(3)SO(3)] ions. V(2)O(3)(CH(3)SO(3))(4) (I2/a, a=1645.2(3), b=583.1(1), c=1670.2(3) pm, β=102.58(3), V=1.5637(5) pm(3), Z=4) adopts a chain structure, too, but contains discrete [VO]-O-[VO] moieties, each coordinated by two bidentate [CH(3)SO(3)] ligands. Additional methanesulfonate ions connect the [V(2)O(3)] groups along [001]. Thermal decomposition of the compounds was monitored under N(2) and O(2) atmosphere by thermogravimetric/differential thermal analysis and XRD measurements. Under N(2) the decomposition proceeds with reduction of the metal leading to the oxides MoO(2), U(3)O(7), V(4)O(7), and VO(2); for MoO(2)(CH(3)SO(3))(2), a small amount of MoS(2) is formed. If the thermal decomposition is carried out in a atmosphere of O(2) the oxides MoO(3) and V(2)O(5) are formed. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

40 CFR Table B-4 to Subpart B of... - Line Voltage and Room Temperature Test Conditions

Code of Federal Regulations, 2012 CFR

2012-07-01

... Conditions B Table B-4 to Subpart B of Part 53 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Testing Performance Characteristics of Automated Methods for SO2, CO, O3, and NO2 Pt. 53, Subpt. B, Table B-4 Table B-4 to Subpart B of Part 53—Line Voltage and Room Temperature Test Conditions Test day...

40 CFR Table B-4 to Subpart B of... - Line Voltage and Room Temperature Test Conditions

Code of Federal Regulations, 2013 CFR

2013-07-01

... Conditions B Table B-4 to Subpart B of Part 53 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Testing Performance Characteristics of Automated Methods for SO2, CO, O3, and NO2 Pt. 53, Subpt. B, Table B-4 Table B-4 to Subpart B of Part 53—Line Voltage and Room Temperature Test Conditions Test day...

40 CFR Table B-4 to Subpart B of... - Line Voltage and Room Temperature Test Conditions

Code of Federal Regulations, 2014 CFR

2014-07-01

... Conditions B Table B-4 to Subpart B of Part 53 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Testing Performance Characteristics of Automated Methods for SO2, CO, O3, and NO2 Pt. 53, Subpt. B, Table B-4 Table B-4 to Subpart B of Part 53—Line Voltage and Room Temperature Test Conditions Test day...

Improvement for enhanced xylanase production by Cellulosimicrobium cellulans CKMX1 using central composite design of response surface methodology.

PubMed

Walia, Abhishek; Mehta, Preeti; Guleria, Shiwani; Shirkot, Chand Karan

2015-12-01

The effects of yeast extract (X 1 ), NH 4 NO 3 (X 2 ), peptone (X 3 ), urea (X 4 ), CMC (X 5 ), Tween 20 (X 6 ), MgSO 4 (X 7 ), and CaCO 3 (X 8 ) on production of xylanase from Cellulosimicrobium cellulans CKMX1 were optimized by statistical analysis using response surface methodology (RSM). The RSM was used to optimize xylanase production by implementing the Central composite design. Statistical analysis of the results showed that the linear, interaction and quadric terms of these variables had significant effects. However, only the linear effect of X 4 , X 5 , interaction effect of X 1 X 7 , X 1 X 8 , X 2 X 3 , X 2 X 8 , X 3 X 6 , X 3 X 8 , X 4 X 6 , X 4 X 7 , X 5 X 7 , X 5 X 8 and quadratic effect of X 3 2 , X 5 2 and X 7 2 found to be insignificant terms in the quadratic model and had no response at significant level. The minimum and maximum xylanase production obtained was 331.50 U/g DBP and 1027.65 U/g DBP, respectively. The highest xylanase activity was obtained from Run No. 30, which consisted of yeast extract (X 1 ), 1.00 g (%); NH 4 NO 3 (X 2 ), 0.20 g (%); peptone (X 3 ), 1.00 g (%); urea (X 4 ), 10 mg (%); CMC (X 5 ), 1.00 g (%); Tween 20 (X 6 ), 0.02 mL (%); CaCO 3 (X 7 ), 0.50 g (%) and MgSO 4 (X 8 ), 9.0 g (%). The optimization resulted in 3.1-fold increase of xylanase production, compared with the lowest xylanase production of 331.50 U/g DBP after 72 h of incubation in stationary flask experiment. Application of cellulase-free xylanase in pulp biobleaching from C. cellulans CKMX1 under C-E P -D sequence has been shown to bring about a 12.5 % reduction of chlorine, decrease of 0.8 kappa points (40 %), and gain in brightness was 1.42 % ISO points in 0.5 % enzyme treated pulp as compared to control.

Variation of wet deposition chemistry in Sequoia National Park, California

USGS Publications Warehouse

Stohlgren, Thomas J.; Parsons, David J.

1987-01-01

Sequoia National Park has monitored wet deposition chemistry in conjunction with the National Atmospheric Deposition Program and National Trends Network (NADP/NTN), on a weekly basis since July, 1980. Annual deposition of H, NO3 and SO4 (0.045, 3.6, and 3.9 kg ha−1 a−1, respectively) is relatively low compared to that measured in the eastern United States, or in the urban Los Angeles and San Francisco areas. Weekly ion concentrations are highly variable. Maximum concentrations of 324,162, and 156 μeq ol−1 of H, NO3 and SO4 have been recorded for one low volume summer storm (1.4 mm). Summer concentrations of NO3 and SO4 average two and five times higher, respectively, than concentrations reported for remote areas in the world. There is considerable variability in the ionic concentration of low volume samples, and much less variability in moderate and high volume samples.

Sources of ozone and sulfate in northeastern United States. Annual progress report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Husain, L.

1980-06-30

Ozone observed at Whiteface Mountain, NY, may be derived from the stratosphere, photochemical production from pollutant NO/sub x/ and hydrocarbons emitted in urban/industrial areas, with subsequent transport of O/sub 3/ to Whiteface Mountain, and/or photochemical production from NO/sub x/ and hyodrocarbons including terpenes, etc., emitted from vegetation in the vicinity of Whiteface Mountain. The principal objective of this work was to assess /sup 7/Be and /sup 32/P as stratospheric tracers and, if possible, use them to quantify stratospheric O/sub 3/. Other objectives of this program were: to study the relationship between O/sub 3/ and SO/sub 4//sup 2 -/, use SO/submore » 4//sup 2 -/ as an indicator of photochemical production originating in urban areas, to study the long-range transport of pollutants and try to identify emission sources and establish daily, monthly, and seasonal variations of SO/sub 4//sup 2 -/ and trace elements thus generating a data base to study long-term trends. The salient features of this study were the first determinations of /sup 7/Be/O/sub 3/ ratios in the lower stratosphere and upper troposphere and gathering continuous data of radionuclides /sup 7/Be, /sup 32/P, and /sup 33/P along with O/sub 3/, SO/sub 4//sup 2 -/, and several trace elements. Some of the significant accomplishments of this study are: a quantitative relationships between /sup 7/Be and O/sub 3/ in the stratosphere was established, and it is applied to estimate stratospheric O/sub 3/ on a global and episodic basis; global /sup 7/Be measurements suggest that the stratospheric influx in the northern hemisphere is twice that in the southern; and, the /sup 7/Be//sup 32/P ratios yield an average transport time of approx. 7 days during spring and summer for stratospheric air from tropopause to Whiteface Mountain, supporting tropopause folding as the predominant mechanism of stratospheric-tropospheric exchange during spring and summer. (JGB)« less

Synthesis, characterization and cytotoxicity studies of palladium(II)-proflavine complexes.

PubMed

Polyanskaya, Tatyana V; Kazhdan, Irene; Motley, D Michelle; Walmsley, Judith A

2010-11-01

An investigation of the reaction of Pd(II) complexes with proflavine (3,6-diaminoacridine) resulted in the isolation of the compounds [Pd(terpy)(proflavine)](NO(3))(HSO(4))*3H(2)O, 1, (terpy = 2,2':6',2″-terpyridine), [Pd(en)(proflavineH))](NO(3))(SO(4)), 2, (en = ethylenediamine), and [Pd(proflavineH)Cl(2)](SO(4))(0.5)*H(2)O, 3. They have been isolated and characterized by NMR, IR, and electro-spray ionization mass spectrometry techniques and by elemental analyses. The proflavine was bonded to the Pd(II) through the endocyclic nitrogen in 1, but through the proflavine NH(2) in 2. Compound 3 appeared to be polymeric in the solid state with a 1:1 mole ratio of Pd(II):proflavine. Upon solution of 3 in DMSO, two unique species were formed. In one species the Pd(II) was bonded to two proflavines through the endocyclic nitrogen (1:2 mole ratio) and in the other species, a Pd(II) was bonded to each NH(2) group of a single proflavine (2:1 mole ratio). Molecular modeling of the equilibrium geometry by Spartan 8 produced structures which were consistent with the experimental data on the solutions of the three compounds. In vitro cytotoxicity testing against two breast cancer cell lines and one ovarian cancer cell line showed that compounds 1 and 3 had significant activity. Copyright © 2010 Elsevier Inc. All rights reserved.

Reactions of small negative ions with O2(a 1[Delta]g) and O2(X 3[Sigma]g-)

NASA Astrophysics Data System (ADS)

Midey, Anthony; Dotan, Itzhak; Seeley, J. V.; Viggiano, A. A.

2009-02-01

The rate constants and product ion branching ratios were measured for the reactions of various small negative ions with O2(X 3[Sigma]g-) and O2(a 1[Delta]g) in a selected ion flow tube (SIFT). Only NH2- and CH3O- were found to react with O2(X) and both reactions were slow. CH3O- reacted by hydride transfer, both with and without electron detachment. NH2- formed both OH-, as observed previously, and O2-, the latter via endothermic charge transfer. A temperature study revealed a negative temperature dependence for the former channel and Arrhenius behavior for the endothermic channel, resulting in an overall rate constant with a minimum at 500 K. SF6-, SF4-, SO3- and CO3- were found to react with O2(a 1[Delta]g) with rate constants less than 10-11 cm3 s-1. NH2- reacted rapidly with O2(a 1[Delta]g) by charge transfer. The reactions of HO2- and SO2- proceeded moderately with competition between Penning detachment and charge transfer. SO2- produced a SO4- cluster product in 2% of reactions and HO2- produced O3- in 13% of the reactions. CH3O- proceeded essentially at the collision rate by hydride transfer, again both with and without electron detachment. These results show that charge transfer to O2(a 1[Delta]g) occurs readily if the there are no restrictions on the ion beyond the reaction thermodynamics. The SO2- and HO2- reactions with O2(a) are the only known reactions involving Penning detachment besides the reaction with O2- studied previously [R.S. Berry, Phys. Chem. Chem. Phys., 7 (2005) 289-290].

Pigeon pea waste as a novel, inexpensive, substrate for production of a thermostable alkaline protease from thermoalkalophilic Bacillus sp. JB-99.

PubMed

Johnvesly, B; Manjunath, B R; Naik, G R

2002-03-01

Thermoalkaliphilic Bacillus sp. JB-99 was grown in a 250 ml Erlenmeyer flask containing 50 ml medium containing (g/l) Pigeon pea waste 10; NaNO3, 5.0; K2HPO4, 5.0; MgSO4 x 2H2O, 0.2 and Na2CO3, 10.0. Incubations were carried out at 50 degrees C on a rotary incubator shaker for 15 h. A high level of extra cellular thermostable protease activity was observed after 24 h incubation. The optimum temperature and pH for activity were 70 degrees C and 11, respectively, so this enzyme showed stable activity at high temperature and under alkaline conditions.

Field survey of trans-boundary air pollution with high time resolution at coastal sites on the Sea of Japan during winter in Japan.

PubMed

Aikawa, Masahide; Hiraki, Takatoshi; Tamaki, Motonori; Kasahara, Mikio; Kondo, Akira; Uno, Itsushi; Mukai, Hitoshi; Shimizu, Atsushi; Murano, Kentaro

2006-11-01

An intensive field survey, with 6-h measurement intervals, of concentrations of chemical species in particulate matter and gaseous compounds was carried out at coastal sites on the Sea of Japan during winter. The concentration variation of SO(2)(g) and HNO(3)(g) were well correlated, whereas the NH(3)(g) concentration variation had no correlation with those of SO(2)(g) and HNO(3)(g). The NH(4) (+) (p)/non-sea-salt- (nss-)SO(4) (2 -)(p) ratio in particulate matter was mainly affected by the location of the sampling site. One or more concentration peaks of nss-Ca(2 +) for survey period were observed. Backward trajectories analyses for the highest nss-Ca(2 +) concentration peaks showed some inconsistency in pathways. We consider that insufficient mixing of the atmosphere and/or insufficient time for the transported air pollutants to react with those discharged locally are the most likely explanations for the discrepancies between the measured products [HNO(3)][NH(3)] and the calculated values.

Effects of Potassium Sulfate [K2SO4] on The Element Contents, Polyphenol Content, Antioxidant and Antimicrobial Activities of Milk Thistle [Silybum Marianum].

PubMed

Yaldiz, Gulsum

2017-01-01

Silybum marianum L. (Milk thistle) is native to the Mediterranean basin and is now widespread throughout the world. It's sprout is used as a herbal medicine for the treatment of liver disease for centuries. The seeds of milk thistle contain silymarin, an isomeric mixture of flavonolignans [silybin, silychristin, and silydianin]. Silymarin acts as a strong anti-hepatotoxic. The objective of this study was to evaluate the influences of potassium sulfate [K 2 SO 4 ] fertilizer doses on polyphenol content, some nutrient elements, antioxidant and antimicrobial activities of milk thistle at experimental fields of Ordu University in Turkey. The antimicrobial activities of seed ethanol extracts and seed oil were tested in vitro against Pseudomonas aeruginosa (P. aeruginosa), Escherichia coli, (E. coli) Staphylococcus aureus (S. aureus), Aspergillus niger (A. niger) and Candida albicans (C. albicans) using the disc diffusion method. Free radical scavenging activity of the ethanolic extracts of milk thistle was determined spectrophotometrically by monitoring the disappearance of 2, 2-diphenyl-1-picrylhydrazil (DPPH•) at 517 nm according to the method described by Brand-Williams et al .[17] The phenolic contents in the ethanolic extracts of milk thistle were determined according to the procedure described by Slinkard and Singleton[19] with a slight modification of using a Folin-Ciocalteu phenolic reagent. The amount of total flavonoid in the ethanolic extracts was measured by aluminum chloride [AlCl 3 ] colorimetric assay. The ions in aerosol samples were determined by using Dionex ICS 1100 Series ion chromatography. Seed and seed oils obtained from obvious doses of potassium sulfate [0, 30, 60, 90 and 120 kg ha -1 fertilizer applications showed antimicrobial activities against E. coli , A. niger and P. aeruginosa . The application of 90 kg ha -1 of K 2 SO 4 on seed oil resulted in the highest antimicrobial activities. At 100 µg mL -1 and 200 µg mL -1 , except the highest potassium application [120 kg ha -1 extract, all extracts showed high and similar DPPH scavenging activity. The highest phenolic compounds were obtained with 30 kg ha -1 of K 2 SO 4 , whereas the use of 60 kg ha -1 caused the highest total flavonoid content. This plant is a good source of K + , Ca +2 , PO4 -3 , and Cl -1 . In this study, increasing doses of potassium sulfate had significant effect on element, polyphenol content, antioxidant and antimicrobial activities of the milk thistle. All tested extracts were active against all tested microbial species.All extracts have shown high and similar DPPH scavenging activity.There was a gradual increase in the biological properties of the milk thistle seeds with rising levels of potassium sulfate.The milk thistle seeds are rather rich sources of K + , Ca +2 , PO4 -3 and Cl -1 potentially bioavailable for human consumption. Abbreviations used: AlCl 3 : aluminum chloride, Ca +2 : calcium, Cl - : chloride, Cr: chromium CE: catechol equivalents, DPPH: 2,2-diphenylpicrylhydrazyl, ABTS: 2,2'-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid, DAP: diamonyum fosfat, F - : fluoride, Fe: iron, K 2 SO 4 : potassium sulfate, K+ : potassium, Li+: lithium, Mg +2 : magnesium, NH 4 + : amonyum, Na + : sodium, NO 2 - : nitrite, NO 3 - : nitrate, Ni: nickel, NaNO 2 : sodium nitrite, NaOH: sodium hidroksit. ND: Not detectable, PO4 -3 : phosphorus, Zn: zinc.

Effects of Potassium Sulfate [K2SO4] on The Element Contents, Polyphenol Content, Antioxidant and Antimicrobial Activities of Milk Thistle [Silybum Marianum

PubMed Central

Yaldiz, Gulsum

2017-01-01

Background: Silybum marianum L. (Milk thistle) is native to the Mediterranean basin and is now widespread throughout the world. It's sprout is used as a herbal medicine for the treatment of liver disease for centuries. The seeds of milk thistle contain silymarin, an isomeric mixture of flavonolignans [silybin, silychristin, and silydianin]. Silymarin acts as a strong anti-hepatotoxic. Objectives: The objective of this study was to evaluate the influences of potassium sulfate [K2SO4] fertilizer doses on polyphenol content, some nutrient elements, antioxidant and antimicrobial activities of milk thistle at experimental fields of Ordu University in Turkey. Methods: The antimicrobial activities of seed ethanol extracts and seed oil were tested in vitro against Pseudomonas aeruginosa (P. aeruginosa), Escherichia coli, (E. coli) Staphylococcus aureus (S. aureus), Aspergillus niger (A. niger) and Candida albicans (C. albicans) using the disc diffusion method. Free radical scavenging activity of the ethanolic extracts of milk thistle was determined spectrophotometrically by monitoring the disappearance of 2, 2-diphenyl-1-picrylhydrazil (DPPH•) at 517 nm according to the method described by Brand-Williams et al.[17] The phenolic contents in the ethanolic extracts of milk thistle were determined according to the procedure described by Slinkard and Singleton[19] with a slight modification of using a Folin-Ciocalteu phenolic reagent. The amount of total flavonoid in the ethanolic extracts was measured by aluminum chloride [AlCl3] colorimetric assay. The ions in aerosol samples were determined by using Dionex ICS 1100 Series ion chromatography. Results: Seed and seed oils obtained from obvious doses of potassium sulfate [0, 30, 60, 90 and 120 kg ha -1 fertilizer applications showed antimicrobial activities against E. coli, A. niger and P. aeruginosa. The application of 90 kg ha -1 of K2SO4 on seed oil resulted in the highest antimicrobial activities. At 100 µg mL-1 and 200 µg mL-1, except the highest potassium application [120 kg ha -1 extract, all extracts showed high and similar DPPH scavenging activity. The highest phenolic compounds were obtained with 30 kg ha -1 of K2SO4, whereas the use of 60 kg ha -1 caused the highest total flavonoid content. This plant is a good source of K+, Ca+2, PO4-3, and Cl-1. Conclusion: In this study, increasing doses of potassium sulfate had significant effect on element, polyphenol content, antioxidant and antimicrobial activities of the milk thistle. SUMMARY All tested extracts were active against all tested microbial species.All extracts have shown high and similar DPPH scavenging activity.There was a gradual increase in the biological properties of the milk thistle seeds with rising levels of potassium sulfate.The milk thistle seeds are rather rich sources of K+, Ca+2, PO4-3 and Cl-1 potentially bioavailable for human consumption. Abbreviations used: AlCl3: aluminum chloride, Ca+2: calcium, Cl-: chloride, Cr: chromium CE: catechol equivalents, DPPH: 2,2-diphenylpicrylhydrazyl, ABTS: 2,2’-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid, DAP: diamonyum fosfat, F-: fluoride, Fe: iron, K2SO4: potassium sulfate, K+ : potassium, Li+: lithium, Mg+2 : magnesium, NH4+ : amonyum, Na+: sodium, NO2-: nitrite, NO3-: nitrate, Ni: nickel, NaNO2: sodium nitrite, NaOH: sodium hidroksit. ND: Not detectable, PO4-3: phosphorus, Zn: zinc PMID:28216891

Hydrogeochemical characterization of fluoride rich groundwater of Wailpalli watershed, Nalgonda District, Andhra Pradesh, India.

PubMed

Reddy, A G S; Reddy, D V; Rao, P N; Prasad, K Maruthy

2010-12-01

The groundwater of Nalgonda district is well known for its very high fluoride content for the past five decades. Many researchers have contributed their scientific knowledge to unravel causes for fluoride enrichment of groundwater. In the present paper, an attempt has been made to relate the high fluoride content in the groundwater to hydrogeochemical characterization of the water in a fracture hard rock terrain--the Wailpally watershed. Groundwater samples collected from all the major geomorphic units in pre- and post-monsoon seasons were analyzed for its major ion constituents such as Ca(2+), Mg(2+), Na(+), K(+), CO3-, HCO3-, Cl(-), SO4(-2), NO3-, and F(-). The groundwaters in the watershed have the average fluoride content of 2.79 mg/l in pre-monsoon and 2.83 mg/l in post-monsoon. Fluoride concentration in groundwater does not show perceptible change neither with time nor in space. The ionic dominance pattern is in the order of Na(+) > Ca(2+) > Mg(2+) > K(-) among cations and HCO3- Cl(-) > SO4(-2) NO3- F(-) among anions in pre-monsoon. In post-monsoon, Mg replaces Ca(2+) and NO3- takes the place of SO4(-2). The Modified Piper diagram reflect that the water belong to Ca(+2)-Mg(+2)-HCO3- to Na(+)-HCO3- facies. Negative chloralkali indices in both the seasons prove that ion exchange between Na(+) and K(+) in aquatic solution took place with Ca(+2) and Mg(+2) of host rock. The interpretation of plots for different major ions and molar ratios suggest that weathering of silicate rocks and water-rock interaction is responsible for major ion chemistry of groundwater in Wailpally watershed. Chemical characteristics and evolution of this fluoride-contaminated groundwater is akin to normal waters of other hard rock terrain; hence, it can be concluded that aquifer material play an important role in the contribution of fluoride in to the accompanying water. High fluoride content in groundwater can be attributed to the continuous water-rock interaction during the process of percolation with fluoride-bearing country rocks under arid, low precipitation, and high evapotranspiration conditions.

Effect of TCE concentration and dissolved groundwater solutes on NZVI-promoted TCE dechlorination and H2 evolution.

PubMed

Liu, Yueqiang; Phenrat, Tanapon; Lowry, Gregory V

2007-11-15

Nanoscale zero-valent iron (NZVI) is used to remediate contaminated groundwater plumes and contaminant source zones. The target contaminant concentration and groundwater solutes (NO3-, Cl-, HCO3-, SO4(2-), and HPO4(2-)) should affect the NZVI longevity and reactivity with target contaminants, but these effects are not well understood. This study evaluates the effect of trichloroethylene (TCE) concentration and common dissolved groundwater solutes on the rates of NZVI-promoted TCE dechlorination and H2 evolution in batch reactors. Both model systems and real groundwater are evaluated. The TCE reaction rate constant was unaffected by TCE concentration for [TCE] < or = 0.46 mM and decreased by less than a factor of 2 for further increases in TCE concentration up to water saturation (8.4 mM). For [TCE] > or = 0.46 mM, acetylene formation increased, and the total amount of H2 evolved at the end of the particle reactive lifetime decreased with increasing [TCE], indicating a higher Fe0 utilization efficiency for TCE dechlorination. Common groundwater anions (5mN) had a minor effect on H2 evolution but inhibited TCE reduction up to 7-fold in increasing order of Cl- < SO4(2-) < HCO3- < HPO4(2). This order is consistent with their affinity to form complexes with iron oxide. Nitrate, a NZVI-reducible groundwater solute, present at 0.2 and 1 mN did not affect the rate of TCE reduction but increased acetylene production and decreased H2 evolution. NO3- present at > 3 mM slowed TCE dechlorination due to surface passivation. NO3- present at 5 mM stopped TCE dechlorination and H2 evolution after 3 days. Dissolved solutes accounted for the observed decrease of NZVI reactivity for TCE dechlorination in natural groundwater when the total organic content was small (< 1 mg/L).

Engine Test and Measurements

NASA Technical Reports Server (NTRS)

Wey, Chown Chou

1999-01-01

Although the importance of aerosols and their precursors are now well recognized, the characterization of current subsonic engines for these emissions is far from complete. Furthermore, since the relationship of engine operating parameters to aerosol emissions is not known, extrapolation to untested and unbuilt engines necessarily remains highly uncertain. 1997 NASA LaRC engine test, as well as the parallel 1997 NASA LaRC flight measurement, attempts to address both issues by expanding measurements of aerosols and aerosol precursors with fuels containing different levels of fuel sulfur content. The specific objective of the 1997 engine test is to obtain a database of sulfur oxides emissions as well as the non-volatile particulate emission properties as a function of fuel sulfur and engine operating conditions. Four diagnostic systems, extractive and non-intrusive (optical), will be assembled for the gaseous and particulate emissions characterization measurements study. NASA is responsible for the extractive gaseous emissions measurement system which contains an array of analyzers dedicated to examining the concentrations of specific gases (NO, NO(x), CO, CO2, O2, THC, SO2) and the smoke number. University of Missouri-Rolla uses the Mobile Aerosol Sampling System to measure aerosol/particulate total concentration, size distribution, volatility and hydration property. Air Force Research Laboratory uses the Chemical Ionization Mass Spectrometer to measure SO2, SO3/H2SO4, and HN03 Aerodyne Research, Inc. uses Infrared Tunable Diode Laser system to measure SO2, SO3, NO, H2O, and CO2.

[Air pollutant emissions of aircraft in China in recent 30 years].

PubMed

He, Ji-Cheng

2012-01-01

Although aircrafts are of great importance in transportation in China, there has been rare study on air pollutant emissions of aircrafts until now. Based on the annually statistical data collected by the Statistic Center of Civil Aviation of China, using the emission factor method derived from fuel consumption, the air pollutant emissions of aircrafts during 1980-2009 were calculated, and their emission intensities and dynamic characteristics were analyzed. The results show that the emissions of SO2, CO, NO(x) and HC from aircrafts of China Civil Aviation increased from 0.31 thousand, 1.89 thousand, 2.25 thousand and 3.14 thousand tons in 1980 to 11.83 thousand, 72.98 thousand, 87.05 thousand and 121.59 thousand tons in 2009, indicating a increase of 0.397 thousand, 2.45 thousand, 2.92 thousand and 4.08 thousand tons per year, respectively. The emission intensities of SO2, CO, NO(x) and HC decreased significantly from 0.624, 3.806, 4.53 and 6.322 g x (t x km)(-1) in 1980 to 0.275, 1.697, 2.025 and 2.828 g x (t x km)(-1) in 2009, respectively. SO2, CO, NO(x) emissions of aircrafts of China Civil Aviation accounted very little of each total emissions in China, and the air pollutant emissions from aircrafts of China Civil Aviation was less than those from other industries in China.

Homogeneous graft copolymerization of styrene onto cellulose in a sulfur dioxide-diethylamine-dimethyl sulfoxide cellulose solvent

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsuzuki, M.; Hagiwara, I.; Shiraishi, N.

1980-12-01

Graft copolymerization of styrene onto cellulose was studied in a homogeneous system (SO/sub 2/(liquid)- diethylamine (DEA)-dimethyl sulfoxide (DMSO) medium)) by ..gamma..-ray mutual irradiation technique. At the same time, homopolymerization of styrene was also examined separately in DMSO, SO/sub 2/-DMSO, DEA-DMSO, and SO/sub 2/-DEA-DMSO media by the same technique. Polymerization of styrene hardly occurs on concentrations above 10 mole SO/sub 2/-DEA complex per mole glucose unit. Maximum percent grafting was obtained in concentrations of 4 mole, after which it decreased rapidly. Total conversion and percent grafting increased with the irradiation time. The value (=0.55) of the slope of the total conversionmore » rate plotted against the dose was only a little higher than the 1/2 which was expected from normal kinetics. No retardation in homopolymerization of styrene in DMSO, SO/sub 2/-DMSO, and DEA-DMSO was evident, while the retardation of homopolymerization in the SO/sub 2/-DEA-DMSO medium was measurable. Sulfur atoms were detected in the polymers obtained in both of SO/sub 2/-DMSO and SO/sub 2/-DEA-DMSO solutions. All of the molecular weights of polymers obtained in the present experiment were very low (3.9 x 10/sup 3/-1.75 x 10/sup 4/).« less

The effect of sea-water intrusion due to the large scale construction in a coastal region

NASA Astrophysics Data System (ADS)

Hyun, S.; Jin, S.; Woo, N. C.; Lee, J.; Lee, H.; Kim, Y.

2010-12-01

This study was carried out for estimating the seawater intrusion at the disturbed aquifer by a large scale construction when building a power plant in a coastal region, located in southeastern part of the Korean peninsula. Groundwater sampling and vertical profiling of electrical conductivity(EC) for 8 monitoring wells were carried. EC profiling results shows that maximum EC for PW-5, 6 and 7 is over 40 mS/cm, for PZ-1, 3, 4 and 8 is 18.76, 4.46, 26.16, 21.42 mS/cm and for PZ-2 is 0.79 mS/cm,respectively. Chemical composition of water samples shows that water types of Na-Cl for PZ-5, 6, and 7 (excavated and backfilled area), Na-Cl-SO4 for PZ-4 and PZ-8, Na-Ca-Mg-Cl for PZ-1, Ca-Na-SO4-Cl for PZ-2, and Mg-Ca-Na-SO4 for PZ-3. In addition, the bivariate plot of SO4/Cl(meq ratios) and SO4(mmol/L) indicates that PZ-4, 5, 6, 7 and 8 appear to be seawater, PZ-1 is located at mixing zone between freshwater and seawater, and PZ-2 is freshwater. However, based on the high SO42- level and (HCO3-/Sum anions} ratio less than 0.8, groundwater at PZ-3 seems to show the gypsum dissolution. The gypsum dissolution was attributed to the effect of sea-water intrusion on ageing of lean concrete that was used for backfill around the PZ-3. Key words : large scale construction, EC profiling, hydrochemistry, sea-water intrusion, concrete ageing Acknowledgement This study has been carried out under the Nuclear R&D Program [No. 2010-0001070] supported by the Ministry of Education, Science and Technology, Republic of Korea.

Hydroxylated and methyl sulfone PCB metabolites in adipose and whole blood of polar bear (Ursus maritimus) from East Greenland.

PubMed

Sandala, G M; Sonne-Hansen, C; Dietz, R; Muir, D C G; Valters, K; Bennett, E R; Born, E W; Letcher, R J

2004-09-20

Persistent methyl sulfone (MeSO2-) and hydroxylated (HO-) polychlorinated biphenyl (PCB) metabolites have emerged as important classes of environmental contaminants in vertebrate, aquatic biota and humans. In the present study, PCB, MeSO2-PCB and HO-PCB concentrations and congener patterns were determined in the whole blood and adipose tissue of male (n = 7) and female (n = 12) polar bears (Ursus maritimus) of random age (3-25 years of age), and collected in 1999-2001 from the Ittoqqortoormiit/Scoresby Sound area in central East Greenland. There was no significant difference (P < 0.05) between males and females with respect to PCB or PCB metabolite concentrations in either tissue. The mean sum (Sigma) PCB concentrations were 7020+/-3366 ng/g lipid weight (lw) (range 2708-18148 ng/g lw) and 46.1+/-44.6 ng/g wet weight (ww) (range 12.6-204.2 ng/g ww) in adipose and blood, respectively. The mean Sigma-HO-PCB concentration in whole blood was 182.3+/-72.1 ng/g ww (range 93.8-382.1 ng/g ww). The mean Sigma-HO-PCB to Sigma-PCB concentration ratios in whole blood were 4.59+/-3.58 (range 1.03-11.88) and 8.30+/-5.56 (range 2.16-19.47) in females and males, respectively, which are the highest ratios reported so far for polar bears from any population, or for any free-ranging animal. Sigma-HO-PCB concentrations were greater than all other major classes of organochlorines (i.e. Sigma-PCBs, Sigma-MeSO2-PCBs, Sigma-chlordanes (CHLs), Sigma-hexachlorocyclohexanes (HCHs) and Sigma-chlorobenzenes (CBzs). The mean Sigma-MeSO2-PCB concentrations were 699+/-836 ng/g lw (range 127-3920 ng/g lw) and 10.9+/-9.6 ng/g ww (range 4.3-52.1 ng/g ww) in the adipose and blood, respectively. Regardless of age and sex, in both adipose and whole blood the MeSO2-PCB congener pattern was dominated by 3'- and 4'-MeSO2-CB101 and -CB87, and 4-MeSO2-CB149 (approx. 70% of the Sigma-MeSO2-PCBs). Minor differences in the MeSO2-PCB congener pattern were observed between blood and adipose, which suggests the possible influence of metabolite structure on mobilization and/or deposition to the adipose tissue. Sixteen HO-PCB congeners and one di-HO-PCB congener were identified, and five HO-PCB isomers and one di-HO-PCB isomer were detected. However, congener patterns were dominated by 4'-OH-CB120, 4-HO-CB146/3-HO-CB153, 4-OH-CB187, 4'-HO-CB172, 4-HO-CB193 and 4,4'-di-HO-CB202 (> 10 ng/g ww). HO-PCB congener patterns in whole blood were not significantly different (P < 0.05) between males and females. Other chlorinated phenolic contaminants, pentachlorophenol (0.3+/-0.3 ng/g ww) and 4-HO-heptachlorostyrene (7.5+/-2.9 ng/g ww) were also detected in blood. To our knowledge, this is to first report comparing PCBs, MeSO2-PCBs and HO-PCBs in whole blood and adipose tissue in a free-ranging wildlife species. HO-PCBs and MeSO2-PCBs are both important circulating contaminants in polar bears from this eastern Greenland population. Given the known toxicities of PCB metabolites, this population of polar bear may be experiencing health risks due to exposure to a complex loading of organohalogen contaminants that include HO-PCB and MeSO2-PCB metabolites.

Observations and modeling of air quality trends over 1990-2010 across the Northern Hemisphere: China, the United States and Europe

NASA Astrophysics Data System (ADS)

Xing, J.; Mathur, R.; Pleim, J.; Hogrefe, C.; Gan, C.-M.; Wong, D. C.; Wei, C.; Gilliam, R.; Pouliot, G.

2015-03-01

Trends in air quality across the Northern Hemisphere over a 21-year period (1990-2010) were simulated using the Community Multiscale Air Quality (CMAQ) multiscale chemical transport model driven by meteorology from Weather Research and Forecasting (WRF) simulations and internally consistent historical emission inventories obtained from EDGAR. Thorough comparison with several ground observation networks mostly over Europe and North America was conducted to evaluate the model performance as well as the ability of CMAQ to reproduce the observed trends in air quality over the past 2 decades in three regions: eastern China, the continental United States and Europe. The model successfully reproduced the observed decreasing trends in SO2, NO2, 8 h O3 maxima, SO42- and elemental carbon (EC) in the US and Europe. However, the model fails to reproduce the decreasing trends in NO3- in the US, potentially pointing to uncertainties of NH3 emissions. The model failed to capture the 6-year trends of SO2 and NO2 in CN-API (China - Air Pollution Index) from 2005 to 2010, but reproduced the observed pattern of O3 trends shown in three World Data Centre for Greenhouse Gases (WDCGG) sites over eastern Asia. Due to the coarse spatial resolution employed in these calculations, predicted SO2 and NO2 concentrations are underestimated relative to all urban networks, i.e., US-AQS (US - Air Quality System; normalized mean bias (NMB) = -38% and -48%), EU-AIRBASE (European Air quality data Base; NMB = -18 and -54%) and CN-API (NMB = -36 and -68%). Conversely, at the rural network EU-EMEP (European Monitoring and Evaluation Programme), SO2 is overestimated (NMB from 4 to 150%) while NO2 is simulated well (NMB within ±15%) in all seasons. Correlations between simulated and observed O3 wintertime daily 8 h maxima (DM8) are poor compared to other seasons for all networks. Better correlation between simulated and observed SO42- was found compared to that for SO2. Underestimation of summer SO42- in the US may be associated with the uncertainty in precipitation and associated wet scavenging representation in the model. The model exhibits worse performance for NO3- predictions, particularly in summer, due to high uncertainties in the gas/particle partitioning of NO3- as well as seasonal variations of NH3 emissions. There are high correlations (R > 0.5) between observed and simulated EC, although the model underestimates the EC concentration by 65% due to the coarse grid resolution as well as uncertainties in the PM speciation profile associated with EC emissions. The almost linear response seen in the trajectory of modeled O3 changes in eastern China over the past 2 decades suggests that control strategies that focus on combined control of NOx and volatile organic compound (VOC) emissions with a ratio of 0.46 may provide the most effective means for O3 reductions for the region devoid of nonlinear response potentially associated with NOx or VOC limitation resulting from alternate strategies. The response of O3 is more sensitive to changes in NOx emissions in the eastern US because the relative abundance of biogenic VOC emissions tends to reduce the effectiveness of VOC controls. Increasing NH3 levels offset the relative effectiveness of NOx controls in reducing the relative fraction of aerosol NO3- formed from declining NOx emissions in the eastern US, while the control effectiveness was assured by the simultaneous control of NH3 emission in Europe.

Different effects of long-term exposures to SO2 and NO2 air pollutants on asthma severity in young adults.

PubMed

Greenberg, Nili; Carel, Rafael S; Derazne, Estela; Bibi, Haim; Shpriz, Manor; Tzur, Dorit; Portnov, Boris A

2016-01-01

Numerous studies demonstrated that exposure to ambient air pollutants contributes to severity and frequency of asthma exacerbations. However, whether common air pollutants, such as nitrogen dioxide (NO2) and sulfur dioxide (SO2), exert differential effects on asthma occurrence and severity is unclear. The aim of this investigation was to determine whether exposure to NO2 and/or SO2 may initiate different long-term effects on prevalence and severity of asthma in young adults. Medical records of 137,040 males, 17 years old, who underwent standard premilitary service health examinations during 1999-2008 were examined. Air-pollution data for NO2 and SO2 were linked to the place of residence of each subject. The influence of specific air pollutants on asthma prevalence and severity was evaluated using bivariate logistic regression, controlling for individuals' sociodemographic attributes. For both ambient air pollutants, there was a significant dose-response effect on severity of asthma at ambient concentrations below the current National Ambient Air Quality Standards. However, in residential areas with high levels of SO2 (13.3-592.7µg/m(3)) and high levels of NO2 (27.2-43.2µg/m(3)) the risk of asthma occurrence was significantly higher than that in residential areas with high levels of NO2 (27.2-43.2 µg/m(3)) and intermediate levels (6.7-13.3 µg/m(3)) of SO2 pollution. The effects of exposure to SO2 and NO2 air pollutants on the respiratory airways system appear to differ, with possible implications regarding medical management, even in cases of exposure to mixtures of these pollutants.

Some new results on shock chemistry in IC 443

NASA Technical Reports Server (NTRS)

Denoyer, L. K.; Frerking, M. A.

1981-01-01

New observations have been made of CO, CO-13, SiO, SO, H2CO, HCO(+), N2H(+), CS, OCS, HCN, and OH in the shocked clouds of IC 443. It is found that at position IC 443 B, (1) the shocked CO is optically thin; (2) the HCO(+)/CO abundance ratio is 4-9 x 10 to the -4 th, representing a tenfold enhancement over that of normal interstellar clouds; (3) there is no enhancement of SO or SIO, as occurs in Orion KL; and (4) there is optically thin preshock OH, confirming a hundredfold enhancement of the OH/CO ratio in the shock.

Modeling dry and wet deposition of sulfate, nitrate, and ammonium ions in Jiuzhaigou National Nature Reserve, China using a source-oriented CMAQ model: Part I. Base case model results.

PubMed

Qiao, Xue; Tang, Ya; Hu, Jianlin; Zhang, Shuai; Li, Jingyi; Kota, Sri Harsha; Wu, Li; Gao, Huilin; Zhang, Hongliang; Ying, Qi

2015-11-01

A source-oriented Community Multiscale Air Quality (CMAQ) model driven by the meteorological fields generated by the Weather Research and Forecasting (WRF) model was used to study the dry and wet deposition of nitrate (NO3(-)), sulfate (SO4(2-)), and ammonium (NH4(+)) ions in the Jiuzhaigou National Nature Reserve (JNNR), China from June to August 2010 and to identify the contributions of different emission sectors and source regions that were responsible for the deposition fluxes. The model performance is evaluated in this paper and the source contribution analyses are presented in a companion paper. The results show that WRF is capable of reproducing the observed precipitation rates with a Mean Normalized Gross Error (MNGE) of 8.1%. Predicted wet deposition fluxes of SO4(2-) and NO3(-) at the Long Lake (LL) site (3100 m a.s.l.) during the three-month episode are 2.75 and 0.34 kg S(N) ha(-1), which agree well with the observed wet deposition fluxes of 2.42 and 0.39 kg S(N) ha(-1), respectively. Temporal variations in the weekly deposition fluxes at LL are also well predicted. Wet deposition flux of NH4(+) at LL is over-predicted by approximately a factor of 3 (1.60 kg N ha(-1)vs. 0.56 kg N ha(-1)), likely due to missing alkaline earth cations such as Ca(2+) in the current CMAQ simulations. Predicted wet deposition fluxes are also in general agreement with observations at four Acid Deposition Monitoring Network in East Asia (EANET) sites in western China. Predicted dry deposition fluxes of SO4(2-) (including gas deposition of SO2) and NO3(-) (including gas deposition of HNO3) are 0.12 and 0.12 kg S(N) h a(-1) at LL and 0.07 and 0.08 kg S(N) ha(-1) at Jiuzhaigou Bureau (JB) in JNNR, respectively, which are much lower than the corresponding wet deposition fluxes. Dry deposition flux of NH4(+) (including gas deposition of NH3) is 0.21 kg N ha(-1) at LL, and is also much lower than the predicted wet deposition flux. For both dry and wet deposition fluxes, predictions from the 12-km resolution nested domain are similar to those from the 36-km resolution parent domain. Copyright © 2015 Elsevier B.V. All rights reserved.

Aerosol chemistry and the effect of aerosol water content on visibility impairment and radiative forcing in Guangzhou during the 2006 Pearl River Delta campaign.

PubMed

Jung, Jinsang; Lee, Hanlim; Kim, Young J; Liu, Xingang; Zhang, Yuanhang; Gu, Jianwei; Fan, Shaojia

2009-08-01

Optical and chemical aerosol measurements were obtained from 2 to 31 July 2006 at an urban site in the metropolitan area of Guangzhou (China) as part of the Program of Regional Integrated Experiment of Air Quality over Pearl River Delta (PRIDE-PRD2006) to investigate aerosol chemistry and the effect of aerosol water content on visibility impairment and radiative forcing. During the PRIDE-PRD2006 campaign, the average contributions of ammonium sulfate, organic mass by carbon (OMC), elemental carbon (EC), and sea salt (SS) to total PM(2.5) mass were measured to be 36.5%, 5.7%, 27.1%, 7.8%, and 3.7%, respectively. Compared with the clean marine period, (NH(4))(2)SO(4), NH(4)NO(3), and OMC were all greatly enhanced (by up to 430%) during local haze periods via the accumulation of a secondary aerosol component. The OMC dominance increased when high levels of biomass burning influenced the measurement site while (NH(4))(2)SO(4) and OMC did when both biomass burning and industrial emissions influenced it. The effect of aerosol water content on the total light-extinction coefficient was estimated to be 34.2%, of which 25.8% was due to aerosol water in (NH(4))(2)SO(4), 5.1% that in NH(4)NO(3), and 3.3% that in SS. The average mass-scattering efficiency (MSE) of PM(10) particles was determined to be 2.2+/-0.6 and 4.6+/-1.7m(2)g(-1) under dry (RH<40%) and ambient conditions, respectively. The average single-scattering albedo (SSA) was 0.80+/-0.08 and 0.90+/-0.04 under dry and ambient conditions, respectively. Not only are the extinction and scattering coefficients greatly enhanced by aerosol water content, but MSE and SSA are also highly sensitive. It can be concluded that sulfate and carbonaceous aerosol, as well as aerosol water content, play important roles in the processes that determine visibility impairment and radiative forcing in the ambient atmosphere of the Guangzhou urban area.

Detection of NO sub x,C2H4 concentrations by using CO and CO2 lasers

NASA Technical Reports Server (NTRS)

Gengchen, W.; Qinxin, K.

1986-01-01

A laser, especially the infrared line tunable laser, opens up a new way to monitor the atmospheric environment, and already has gotten effective practical application. One of the most serious problems in open path remote measurement at atmospheric pressure is the broadening effect which leads to increased linewidths, spectral interferences, and, as a result, tends to reduce detection sensitivity, so measuring laser wavelengths should be selected carefully, and interaction between the measuring wavelength and gas to be measured must be known very well. Therefore, N2O, No, NO2, CH4, NH3 and C2H4 absorption properties at some lines of CO and CO2 line tunable lasers were studied. The absorption coefficients of NO, NO2, and C2H4; some results on detection of NO sub x, C2H4 concentrations in both laboratory and field; and selection of measuring wavelengths and error analysis are discussed.

Corrosion of metals and alloys in sulfate melts at 750 C

NASA Technical Reports Server (NTRS)

Misra, A. K.

1986-01-01

The corrosion of Ni, Co, Ni-10Cr, Co-21Cr, and IN738 was studied at 750 C in the presence of molten sulfate mixtures (Na2SO4-Li2SO4 and Na2SO4-CoSO4) and in an atmosphere consisting of O2 + 0.12 percent SO2-SO3. The corrosion was observed to be similar for both Na2SO4-Li2SO4 and Na2SO4-CoSO4 melts. The corrosion of Ni and Co took place by the formation of a mixed oxide plus sulfide scale, very similar to the corrosion in SO2 or SO3 alone. The initial stage for the corrosion of Ni-10Cr involved the formation of a thick NiO + Ni3S2 duplex scale, and Cr sulfide was formed during the later stages. A pitting type of morphology was observed for both Co-21Cr and IN738. The pit was Cr sulfide at the beginning, and subsequently the sulfides oxidized to Cr2O3. A base-metal oxide layer was present above the pit, and this was observed to be formed very early in the corrosion process. A mechanism is proposed to explain this. In general, the formation of sulfides appears to be the primary mode of degradation in mixed sulfide melts.

Influence of different aluminum salts on the photocatalytic properties of Al doped TiO2 nanoparticles towards the degradation of AO7 dye.

PubMed

Luo, Jin-Ling; Wang, Shi-Fa; Liu, Wei; Tian, Cheng-Xiang; Wu, Ju-Wei; Zu, Xiao-Tao; Zhou, Wei-Lie; Yuan, Xiao-Dong; Xiang, Xia

2017-08-14

Three kinds of Al-TiO 2 samples and pure TiO 2 samples were synthesized via a modified polyacrylamide gel route using different aluminum salts, including Al 2 (SO 4 ) 3 ∙18H 2 O, AlCl 3 , and Al(NO 3 ) 3 ∙9H 2 O under identical conditions. The influence of different aluminum salts on the phase purity, morphologies, thermal stability of anatase and photocatalytic properties of the as-prepared Al-TiO 2 nanoparticles were studied. The energy gap (Eg) of Al-TiO 2 nanoparticles decreases due to Al ion doping into TiO 2 . The photocatalytic activities of the Al-TiO 2 samples were investigated by the degradation of acid orange 7 dye in aqueous solution under simulated solar irradiation. The Al-TiO 2 nanoparticles prepared from Al(NO 3 ) 3 ∙9H 2 O exhibit the best photocatalytic activity among the four kinds of samples, followed in turn by the Al-TiO 2 nanoparticles prepared with AlCl 3 , Al 2 (SO 4 ) 3 ∙18H 2 O and pure TiO 2 . The different performances are attributed to complex effects of Eg, particle size, surface morphology, phase purity and the defect sites of the Al-TiO 2 nanoparticles.

Novel Co- or Ni-Mn binary oxide catalysts with hydroxyl groups for NH3-SCR of NOx at low temperature

NASA Astrophysics Data System (ADS)

Gao, Fengyu; Tang, Xiaolong; Yi, Honghong; Zhao, Shunzheng; Wang, Jiangen; Shi, Yiran; Meng, Xiaomi

2018-06-01

Novel hydroxyl-containing Me-Mn binary oxides (Me = Co, Ni) were prepared for the selective catalytic reduction of NOx with NH3 by a combined complexation-esterification method. The binary oxides of Co-MnOx and Ni-MnOx with mixed crystal phases of Mn3O4 and Co3O4, Mn2O3 and NiMnO3 were obtained at 550 °C. SCR activity decreased in the order of Mn3O4-Co3O4-OH > Mn2O3-NiMnO3-OH > Mn2O3-OH > Mn3O4-OH, benefiting from the high concentration of chemisorbed oxygen and effective electron transformation of cations. Mn2O3-containing catalysts had better selectivity to N2 than those containing Mn3O4. Higher selectivity to N2O over Mn3O4-containing catalysts was attributed to the depth dehydrogenation of coordinated NH3 by the active oxygen species with lower Mnsbnd O band energy. The typical Eley-Rideal mechanism over Mn3O4-OH and Mn3O4-Co3O4-OH, and the additional formation pathway of NH4NO3 species over Mn2O3-OH and Mn2O3-NiMnO3-OH catalysts were proposed via the in-situ DRIFTS experiments. Although the Co and Ni elements had a good role in delaying the poisoning of SO2, these catalysts were eventually sulfated by SO2 over the postponement, which might due to the metal sulfate and ammonia hydrogensulfite species.

Air pollutants and health outcomes: Assessment of confounding by influenza

NASA Astrophysics Data System (ADS)

Thach, Thuan-Quoc; Wong, Chit-Ming; Chan, King-Pan; Chau, Yuen-Kwan; Neil Thomas, G.; Ou, Chun-Quan; Yang, Lin; Peiris, Joseph S. M.; Lam, Tai-Hing; Hedley, Anthony J.

2010-04-01

We assessed confounding of associations between short-term effects of air pollution and health outcomes by influenza using Hong Kong mortality and hospitalization data for 1996-2002. Three measures of influenza were defined: (i) intensity: weekly proportion of positive influenza viruses, (ii) epidemic: weekly number of positive influenza viruses ≥4% of the annual number for ≥2 consecutive weeks, and (iii) predominance: an epidemic period with co-circulation of respiratory syncytial virus <2% of the annual positive isolates for ≥2 consecutive weeks. We examined effects of influenza on associations between nitrogen dioxide (NO 2), sulfur dioxide (SO 2), particulate matter with aerodynamic diameter ≤10 μm (PM 10) and ozone (O 3) and health outcomes including all natural causes mortality, cardiorespiratory mortality and hospitalization. Generalized additive Poisson regression model with natural cubic splines was fitted to control for time-varying covariates to estimate air pollution health effects. Confounding with influenza was assessed using an absolute difference of >0.1% between unadjusted and adjusted excess risks (ER%). Without adjustment, pollutants were associated with positive ER% for all health outcomes except asthma and stroke hospitalization with SO 2 and stroke hospitalization with O 3. Following adjustment, changes in ER% for all pollutants were <0.1% for all natural causes mortality, but >0.1% for mortality from stroke with NO 2 and SO 2, cardiac or heart disease with NO 2, PM 10 and O 3, lower respiratory infections with NO 2 and O 3 and mortality from chronic obstructive pulmonary disease with all pollutants. Changes >0.1% were seen for acute respiratory disease hospitalization with NO 2, SO 2 and O 3 and acute lower respiratory infections hospitalization with PM 10. Generally, influenza does not confound the observed associations of air pollutants with all natural causes mortality and cardiovascular hospitalization, but for some pollutants and subgroups of cardiorespiratory mortality and respiratory hospitalization there was evidence to suggest confounding by influenza.

[Effects of antiseptic on the analysis of greenhouse gases concentrations in lake water].

PubMed

Xiao, Qi-Tao; Hu, Zheng-Hu; James, Deng; Xiao, Wei; Liu, Shou-Dong; Li, Xu-Hui

2014-01-01

To gain insight into antiseptic effects on the concentrations of CO2, CH4, and N2O in lake water, antisepetic (CuSO4 and HgCl2) were added into water sample, and concentrations of greenhouse gases were measured by the gas chromatography based on water equilibrium method. Experiments were conducted as following: the control group without antisepetic (CK), the treatment group with 1 mL CuSO4 solution (T1), the treatment group with 5 mL CuSO4 solution (T2), and the treatment group with 0.5 mL HgCl2 solution (T3). All groups were divided into two batches: immediately analysis (I), and after 2 days analysis (II). Results showed that CuSO4 and HgCl2 significantly increased CO2 concentration, the mean CO2 concentration (Mco2) of CK (I) and CK (II) were (11.5 +/- 1.47) micromol x L(-1) and (14.38 +/- 1.59) micromol x L(-1), respectively; the Mco2 of T1 (I) and T1 (II) were (376 +/- 70) micromol x L(-1) and (448 +/- 246.83) micromol x L(-1), respectively; the Mco2 of T2 (I) and T2 (II) were (885 +/- 51.53) micromol x L(-1) and (988.83 +/- 101.96) micromol x L(-1), respectively; the Mco2 of T3 (I) and T3 (II) were (287.19 +/- 30.01) micromol x L(-1) and (331.33 +/- 22.06) micromol x L(-1), respectively. The results also showed that there was no difference in CH4 and N2O concentrations among treatments. Water samples should be analyzed as soon as possible after pretreatment. Our findings suggest that adding antiseptic may lead an increase in CO2 concentration.

Long-term atmospheric deposition of nitrogen, phosphorus and sulfate in a large oligotrophic lake

PubMed Central

Craft, James A.; Stanford, Jack A.

2015-01-01

We documented significantly increasing trends in atmospheric loading of ammonium (NH4) and nitrate/nitrite (NO2/3) and decreasing trends in total phosphorus (P) and sulfate (SO4) to Flathead Lake, Montana, from 1985 to 2004. Atmospheric loading of NO2/3 and NH4 increased by 48 and 198% and total P and SO4 decreased by 135 and 39%. The molar ratio of TN:TP also increased significantly. Severe air inversions occurred periodically year-round and increased the potential for substantial nutrient loading from even small local sources. Correlations between our loading data and various measures of air quality in the basin (e.g., particulate matter <10 µm in size, aerosol fine soil mass, aerosol nutrient species, aerosol index, hectares burned) suggest that dust and smoke are important sources. Ammonium was the primary form of N in atmospheric deposition, whereas NO3 was the primary N form in tributary inputs. Atmospheric loading of NH4 to Flathead Lake averaged 44% of the total load and on some years exceeded tributary loading. Primary productivity in the lake is colimited by both N and P most of the year; and in years of high atmospheric loading of inorganic N, deposition may account for up to 6.9% of carbon converted to biomass. PMID:25802810

Long-term atmospheric deposition of nitrogen, phosphorus and sulfate in a large oligotrophic lake.

PubMed

Ellis, Bonnie K; Craft, James A; Stanford, Jack A

2015-01-01

We documented significantly increasing trends in atmospheric loading of ammonium (NH4) and nitrate/nitrite (NO2/3) and decreasing trends in total phosphorus (P) and sulfate (SO4) to Flathead Lake, Montana, from 1985 to 2004. Atmospheric loading of NO2/3 and NH4 increased by 48 and 198% and total P and SO4 decreased by 135 and 39%. The molar ratio of TN:TP also increased significantly. Severe air inversions occurred periodically year-round and increased the potential for substantial nutrient loading from even small local sources. Correlations between our loading data and various measures of air quality in the basin (e.g., particulate matter <10 µm in size, aerosol fine soil mass, aerosol nutrient species, aerosol index, hectares burned) suggest that dust and smoke are important sources. Ammonium was the primary form of N in atmospheric deposition, whereas NO3 was the primary N form in tributary inputs. Atmospheric loading of NH4 to Flathead Lake averaged 44% of the total load and on some years exceeded tributary loading. Primary productivity in the lake is colimited by both N and P most of the year; and in years of high atmospheric loading of inorganic N, deposition may account for up to 6.9% of carbon converted to biomass.

Multivariate statistics as means of tracking atmospheric pollution trends in Western Poland.

PubMed

Astel, Aleksander M; Walna, Barbara; Simeonov, Vasil; Kurzyca, Iwona

2008-02-15

This study was carried out over a period of 4 years (2002-2005) at 2 sites located in western Poland differing as regards to human impact by analysis of chemical composition of bulk precipitation. The aim of the study was to determine the sources of pollutions and assess their quantitative contribution to the bulk precipitation composition and to analyse long term-changes in the chemical quality of precipitation. Based on this information the possible transboundary impacts of pollution were also determined. The samples were characterized by determining the values of pH, electrolytic conductivity and concentration levels of Cl(-), F(-), SO(4)(2-), NO(3)(-), Na(+), K(+), Mg(2+), Ca(2+) and NH(4)(+). Analytical measurements were connected with application of principal component regression (PCR) and time series analysis (TS). Based on PCR results three major sources of pollutants in central part of Poland have been identified and quantitatively assessed as follows: "combined" (Poznań - 31%, WNP - 32%), "soil-particulates" (Poznań - 2%, WNP - 26%), "anthropogenic-fossil fuels" (Poznań - 43%, WNP - 23%). Time series analysis enabled discovering 12-month time cycle for NO(3)(-), NH(4)(+), Cl(-), F(-) and SO(4)(2-) in average monthly concentration values in bulk precipitation collected in Wielkopolski National Park. Seasonal variation in the emission of precursors of NO(3)(-) and NH(4)(+) was caused by changes in intensity of fertilizer application in agriculture and automobile exhaust emissions. Decreasing trend was visible for sulphates, nitrates, chlorides and fluorides which is an important indication of the acid rain reduction in the ecologically protected area and in Poznań.

Physicochemical quality evaluation of groundwater and development of drinking water quality index for Araniar River Basin, Tamil Nadu, India.

PubMed

Jasmin, I; Mallikarjuna, P

2014-02-01

Groundwater is the most important natural resource which cannot be optimally used and sustained unless its quality is properly assessed. In the present study, the spatial and temporal variations in physicochemical quality parameters of groundwater of Araniar River Basin, India were analyzed to determine its suitability for drinking purpose through development of drinking water quality index (DWQI) maps of the post- and pre-monsoon periods. The suitability for drinking purpose was evaluated by comparing the physicochemical parameters of groundwater in the study area with drinking water standards prescribed by the World Health Organization (WHO) and Bureau of Indian Standards (BIS). Interpretation of physicochemical data revealed that groundwater in the basin was slightly alkaline. The cations such as sodium (Na(+)) and potassium (K(+)) and anions such as bicarbonate (HCO3 (-)) and chloride (Cl(-)) exceeded the permissible limits of drinking water standards (WHO and BIS) in certain pockets in the northeastern part of the basin during the pre-monsoon period. The higher total dissolved solids (TDS) concentration was observed in the northeastern part of the basin, and the parameters such as calcium (Ca(2+)), magnesium (Mg(2+)), sulfate (SO4 (2-)), nitrate (NO3 (-)), and fluoride (F(-)) were within the limits in both the seasons. The hydrogeochemical evaluation of groundwater of the basin demonstrated with the Piper trilinear diagram indicated that the groundwater samples of the area were of Ca(2+)-Mg(2+)-Cl(-)-SO4 (2-), Ca(2+)-Mg(2+)-HCO3 (-) and Na(+)-K(+)-Cl(-)-SO4 (2-) types during the post-monsoon period and Ca(2+)-Mg(2+)-Cl(-)-SO4 (2-), Na(+)-K(+)-Cl(-)-SO4 (2-) and Ca(2+)-Mg(2+)-HCO3 (-) types during the pre-monsoon period. The DWQI maps for the basin revealed that 90.24 and 73.46% of the basin area possess good quality drinking water during the post- and pre-monsoon seasons, respectively.

Prussian blue analogues for CO(2) and SO(2) capture and separation applications.

PubMed

Thallapally, Praveen K; Motkuri, Radha Kishan; Fernandez, Carlos A; McGrail, B Peter; Behrooz, Ghorishi S

2010-06-07

Adsorption isotherms of pure gases present in flue gas including CO(2), N(2), SO(2), NO, H(2)S, and water were studied using prussian blues of chemical formula M(3)[Co(CN)(6)](2).nH(2)O (M = Co, Zn) using an HPVA-100 volumetric gas analyzer and other spectroscopic methods. All the samples were characterized, and the microporous nature of the samples was studied using the BET isotherm. These materials adsorbed 8-10 wt % of CO(2) at room temperature and 1 bar of pressure with heats of adsorption ranging from 200 to 300 Btu/lb of CO(2), which is lower than monoethanolamine (750 Btu/lb of CO(2)) at the same mass loading. At high pressures (30 bar and 298 K), these materials adsorbed approximately 20-30 wt % of CO(2), which corresponds to 3 to 5 molecules of CO(2) per formula unit. Similar gas adsorption isotherms for SO(2), H(2)S, and NO were collected using a specially constructed volumetric gas analyzer. At close to 1 bar of equilibrium pressure, these materials sorb around 2.5, 2.7, and 1.2 mmol/g of SO(2), H(2)S, and NO. In particular, the uptake of SO(2) and H(2)S in Co(3)[Co(CN)(6)](2) is quite significant since it sorbs around 10 and 4.5 wt % at 0.1 bar of pressure. The stability of prussian blues before and after trace gases was studied using a powder X-ray diffraction instrument, which confirms these materials do not decompose after exposure to trace gases.

Process for simultaneous removal of SO[sub 2] and NO[sub x] from gas streams

DOEpatents

Rosenberg, H.S.

1987-02-03

A process is described for simultaneous removal of SO[sub 2] and NO[sub x] from a gas stream that includes flowing the gas stream to a spray dryer and absorbing a portion of the SO[sub 2] content of the gas stream and a portion of the NO[sub x] content of the gas stream with ZnO by contacting the gas stream with a spray of an aqueous ZnO slurry; controlling the gas outlet temperature of the spray dryer to within the range of about a 0 to 125 F approach to the adiabatic saturation temperature; flowing the gas, unreacted ZnO and absorbed SO[sub 2] and NO[sub x] from the spray dryer to a fabric filter and collecting any solids therein and absorbing a portion of the SO[sub 2] remaining in the gas stream and a portion of the NO[sub x] remaining in the gas stream with ZnO; and controlling the ZnO content of the aqueous slurry so that sufficient unreacted ZnO is present in the solids collected in the fabric filter to react with SO[sub 2] and NO[sub x] as the gas passes through the fabric filter whereby the overall feed ratio of ZnO to SO[sub 2] plus NO[sub x] is about 1.0 to 4.0 moles of ZnO per of SO[sub 2] and about 0.5 to 2.0 moles of ZnO per mole of NO[sub x]. Particulates may be removed from the gas stream prior to treatment in the spray dryer. The process further allows regeneration of ZnO that has reacted to absorb SO[sub 2] and NO[sub x] from the gas stream and acid recovery. 4 figs.

Environmental impact of municipal dumpsite leachate on ground-water quality in Jawaharnagar, Rangareddy, Telangana, India

NASA Astrophysics Data System (ADS)

Soujanya Kamble, B.; Saxena, Praveen Raj

2017-10-01

The aim of the present work was to study the impact of dumpsite leachate on ground-water quality of Jawaharnagar village. Leachate and ground-water samples were investigated for various physico-chemical parameters viz., pH, total dissolved solids (TDS), total hardness (TH), calcium (Ca2+), magnesium (Mg2+), sodium (Na+), potassium (K+), chloride (Cl-), carbonates (CO3 2-), bicarbonates (HCO3 -), nitrates (NO3 -), and sulphates (SO4 2-) during dry and wet seasons in 2015 and were reported. The groundwater was hard to very hard in nature, and the concentrations of total dissolved solids, chlorides, and nitrates were found to be exceeding the permissible levels of WHO drinking water quality standards. Piper plots revealed that the dominant hydrochemical facies of the groundwater were of calcium chloride (CaCl2) type and alkaline earths (Ca2+ and Mg2+) exceed the alkali (Na+ and SO4 2-), while the strong acids (Cl- and SO4 2-) exceed the weak acids (CO3 2- and HCO3 -). According to USSL diagram, all the ground-water samples belong to high salinity and low-sodium type (C3S1). Overall, the ground-water samples collected around the dumpsite were found to be polluted and are unfit for human consumption but can be used for irrigation purpose with heavy drainage and irrigation patterns to control the salinity.

Kinetics and mechanism of corrosion of SiC by molten salts

NASA Technical Reports Server (NTRS)

Jacobson, N. S.

1986-01-01

Corrosion of sintered alpha-SiC under thin films of Na2CO3/CO2, Na2SO4/O2, and Na2SO4/SO3 was investigated at 1000 C. Chemical analysis was used to follow silicate and silica evolution as a function of time. This information coupled with morphology observations leads to a detailed corrosion mechanism. In all cases the corrosion reactions occur primarily in the first few hours. In the Na2CO3/CO2 case, rapid oxidation and dissolution lead to a thick layer of silicate melt in about 0.25 h. After this, silica forms a protective layer on the carbide. In the Na2SO4/O2 case, a similar mechanism occurs. In the Na2SO4/SO3 case, a porous nonprotective layer of SiO2 grows directly on the carbide, and a silicate melt forms above this. In addition, SiO2 and regenerated Na2SO4 form at the melt/gas interface due to reaction of silicate with SO3 and SO2 + O2. The reaction slows when the lower silica layer becomes nonporous.

The Effects of Inorganic Nitrogen form and CO2 Concentration on Wheat Yield and Nutrient Accumulation and Distribution

PubMed Central

Carlisle, Eli; Myers, Samuel; Raboy, Victor; Bloom, Arnold

2012-01-01

Inorganic N is available to plants from the soil as ammonium (NH4+) and nitrate (NO3-). We studied how wheat grown hydroponically to senescence in controlled environmental chambers is affected by N form (NH4+ vs. NO3−) and CO2 concentration (“subambient,” “ambient,” and “elevated”) in terms of biomass, yield, and nutrient accumulation and partitioning. Wheat supplied with NH4+ as a sole N source had the strongest response to CO2 concentration. Plants exposed to subambient and ambient CO2 concentrations typically had the greatest biomass and nutrient accumulation under both N forms. In general NH4+-supplied plants had higher concentrations of total N, P, K, S, Ca, Zn, Fe, and Cu, while NO3--supplied plants had higher concentrations of Mg, B, Mn, and NO3- - N. NH4+-supplied plants contained amounts of phytate similar to NO3−-supplied plants but had higher bioavailable Zn, which could have consequences for human health. NH4+-supplied plants allocated more nutrients and biomass to aboveground tissues whereas NO3+-supplied plants allocated more nutrients to the roots. The two inorganic nitrogen forms influenced plant growth and nutrient status so distinctly that they should be treated as separate nutrients. Moreover, plant growth and nutrient status varied in a non-linear manner with atmospheric CO2 concentration. PMID:22969784

[Study on air quality and pollution meteorology conditions of Guangzhou during the 2010 Asian games].

PubMed

Li, Ting-Yuan; Deng, Xue-Jiao; Fan, Shao-Jia; Wu, Dui; Li, Fei; Deng, Tao; Tan, Hao-Bo; Jiang, De-Hai

2012-09-01

Based on the monitoring data of NO2, O3, SO2, PM, visibility, regional air quality index (RAQI) and the atmospheric transport and diffusion data from Nov. 4, 2010 to Dec. 10, 2010 in Guangzhou area, the variations of air quality and meteorological conditions during the Guangzhou Asian Games were analyzed. It was found that, during the Asian Games, the air quality was better than the air quality before or after the Asian Games. The visibility was greater than the visibility before or after the Asian Games, while the concentrations of PM1 and PM2.5 were lower. The correlation coefficient between visibility and the concentrations of PM1, PM2.5 indicated anti-correlation relationships. Daily and hourly concentrations of NO2 and SO2 met the primary ambient air quality standards, whereas the daily concentration of PM10 and hourly concentration of O3 met the secondary ambient air quality standards. Pollutants had been well controlled during the Asian Games. The concentration of SO2 in Guangzhou was influenced by local sources and long distance transmission, while the concentration of NO2 was significantly influenced by local sources. The emissions of NO2, SO2 and PM10 surrounding Guangzhou had a trend to affect the concentrations in Guangzhou, but the situation of O3 was opposite, the relatively high concentration of O3 in Guangzhou had tendency to be transported to the surrounding areas. The pollution meteorology conditions in the period of Asian Games were better than the conditions before or after the Asian Games. The decrease in the concentrations during the Asian Games did not only benefit from the emission control by the government, but also from the good meteorological conditions.

Typical winter haze pollution in Zibo, an industrial city in China: Characteristics, secondary formation, and regional contribution.

PubMed

Li, Hui; Ma, Yongliang; Duan, Fengkui; He, Kebin; Zhu, Lidan; Huang, Tao; Kimoto, Takashi; Ma, Xiaoxuan; Ma, Tao; Xu, Lili; Xu, Beiyao; Yang, Shuo; Ye, Siqi; Sun, Zhenli; An, Jiutao; Zhang, Zhaolu

2017-10-01

Heavy haze pollution occurs frequently in northern China, most critically in the Beijing-Tianjin-Hebei area (BTH). Zibo, an industrial city located in Shandong province, is often listed as one of the top ten most polluted cities in China, particularly in winter. However, no studies of haze in Zibo have been conducted, which limits the understanding of the source and formation of haze pollution in this area, as well as mutual effects with the BTH area. We carried out online and continuous integrated field observation of particulate matter in winter, from 11 to 25 January 2015. SO 4 2- , NO 3 - , and NH 4 + (SIA) and organics were the main constituents of PM 2.5 , contributing 59.4% and 33.6%, respectively. With the increasing severity of pollution, the contribution of SIA increased while that of organics decreased. Meteorological conditions play an important role in haze formation; high relative humidity (RH) and low wind speed increased both the accumulation of pollutants and the secondary transition from gas precursors (gas-particle phase partitioning). Since RH and the presence of O 3 can indicate heterogeneous and photochemistry processes, respectively, we carried out correlation analysis and linear regression to identify their relative importance to the three main secondary species (sulfate, nitrate, and secondary organic carbon (SOC)). We found that the impact of RH is in the order of SO 4 2-  > NO 3 -  > SOC, while the impact of O 3 is reversed, in the order of SOC > NO 3 -  > SO 4 2- , indicating different effect of these factors on the secondary formation of main species in winter. Cluster analysis of backward trajectories showed that, during the observation period, six directional sources of air masses were identified, and more than 90% came from highly industrialized areas, indicating that regional transport from industrialized areas aggravates the haze pollution in Zibo. Inter-regional joint prevention and control is necessary to prevent further deterioration of the air quality. Copyright © 2017. Published by Elsevier Ltd.

MnFe2O4 as a gas sensor towards SO2 and NO2 gases

NASA Astrophysics Data System (ADS)

Rathore, Deepshikha; Mitra, Supratim

2016-05-01

The chemical co-precipitation method was used to synthesize MnFe2O4 nanoparticles. Single cubic phase formation of nanoparticles was confirmed by X-ray diffraction technique. The average particle size of MnFe2O4 nanoparticles was found to be 10.7 nm using Scherrer formula. The ultrafine powder of MnFe2O4 nanoparticles was pressed to design pellet of 10 mm diameter and 1mm thickness. Copper electrodes have been deposited on the surface of pellet using silver paste in the form of capacitor. Fabricated gas sensing device of MnFe2O4 nanoparticles was tested towards SO2 and NO2 gases. Cole-Cole plot of MnFe2O4 was investigated with the help of electrochemical workstation. The performance of the sensors including sensitivity, response and recovery time was also determined. It was observed that the MnFe2O4 nanoparticles are more sensible for NO2 gas as compared to SO2 gas.

Barium isotope fractionation during the experimental transformation of aragonite to witherite and of gypsum to barite, and the effect of ion (de)solvation.

PubMed

Böttcher, Michael E; Neubert, Nadja; von Allmen, Katja; Samankassou, Elias; Nägler, Thomas F

2018-06-01

In this study, we present the experimental results for stable barium (Ba) isotope fractionation ( 137 Ba/ 134 Ba) during the transformation of aragonite (CaCO 3 ) and gypsum (CaSO 4 ·2H 2 O) in Ba-bearing aqueous solution to witherite (BaCO 3 ) and barite (BaSO 4 ), respectively. The process was studied at three temperatures between 4 and 60 °C. In all cases, the transformation leads to a relative enrichment of the lighter 134 Ba isotope in the solid compared to the aqueous solution, with 137/134 Ba enrichment factors between -0.11 and -0.17 ‰ for BaCO 3 , and -0.21 and -0.26 ‰ for BaSO 4 . The corresponding mass-dependent 138/134 Ba enrichment factors are -0.15 to -0.23 ‰ for BaCO 3 , and -0.28 to -0.35 ‰ for BaSO 4 . The magnitude of isotope fractionation is within the range of recent reports for witherite and barite formation, as well as trace Ba incorporation into orthorhombic aragonite, and no substantial impact of temperature can be found between 4 and 80 °C. In previous studies, ion (de)solvation has been suggested to impact both the crystallization process of Ba-bearing solids and associated Ba isotope fractionation. Precipitation experiments of BaSO 4 and BaCO 3 using an methanol-containing aqueous solution indicate only a minor effect of ion and crystal surface (de)solvation on the overall Ba isotope fractionation process.

In vitro shoot growth of Brugmansia x candida Pers.

USDA-ARS?s Scientific Manuscript database

The objective of this study was to improve the growth of in vitro shoot cultures of Brugmansia × candida 'Creamsickle'. Several mineral nutrient experiments were conducted to determine the effect of NH4+, NO3-, K+, FeSO4/EDTA, ZnSO4, MnSO4, and CuSO4 on quality, leaf width and length, size and weigh...

Spatiotemporal variations of hydrogeochemistry and its controlling factors in the Gandaki River Basin, Central Himalaya Nepal.

PubMed

Pant, Ramesh Raj; Zhang, Fan; Rehman, Faizan Ur; Wang, Guanxing; Ye, Ming; Zeng, Chen; Tang, Handuo

2018-05-01

The characterization and assessment of water quality in the head water region of Himalaya is necessary, given the immense importance of this region in sustaining livelihoods of people and maintaining ecological balance. A total of 165 water samples were collected from 55 sites during pre-monsoon, monsoon and post-monsoon seasons in 2016 from the Gandaki River Basin of the Central Himalaya, Nepal. The pH, EC values and TDS concentrations were measured in-situ and the concentrations of major ions (Ca 2+ , Mg 2+ , K + , Na + , Cl - , SO 4 2- , NO 3 - ) and Si were analyzed in laboratory. Correlation matrices, paired t-test, cluster analysis, principal component analysis (PCA), the Piper, Gibbs, and Mixing plots, and saturation index were applied to the measurements for evaluating spatiotemporal variation of the major ions. The results reveal mildly alkaline pH values and the following pattern of average ionic dominance: Ca 2+ >Mg 2+ >Na + >K + for cations and HCO 3 - >SO 4 2 - >Cl - >NO 3 - for anions. The results of PCA, Gibbs plot and the ionic relationships displayed the predominance of geogenic weathering processes in areas with carbonate dominant lithology. This conclusion is supported by geochemically different water facies identified in the Piper plot as Ca-HCO 3 (83.03%), mixed Ca-Mg-Cl (12.73.0%) and Ca-Cl (4.24%). Pronounced spatiotemporal heterogeneity demonstrates the influence of climatic, geogenic and anthropogenic conditions. For instance, the Ca 2+ -SO 4 2- , Mg 2+ -SO 4 2- and Na + -Cl - pairs exhibit strong positive correlation with each other in the upstream region, whereas relatively weak correlation in the downstream region, likely indicating the influence of evapo-crystallization processes in the upstream region. Analyses of the suitability of the water supply for drinking and irrigation reveal that the river has mostly retained its natural water quality but poses safety concern at a few locations. Knowledge obtained through this study can contribute to the sustainable management of water quality in the climatically and lithologically distinct segments of the Himalayan river basins. Copyright © 2017 Elsevier B.V. All rights reserved.

Evaluation of the environmental epidemiologic data and methodology for the air quality standard in Beijing

NASA Astrophysics Data System (ADS)

Li, Xu; Jiang, Yanfeng; Yin, Ling; Liu, Bo; Du, Pengfei; Hassan, Mujtaba; Wang, Shigong; Li, Tanshi

2017-09-01

To evaluate the relationship between exposure to air pollutants and respiratory emergency room visits, a generalized additive model (GAM) was used to analyze the exposure-effect relationship between air pollutants and respiratory emergency room visits. The results showed that NO2, SO2, and PM10 have positive relationships with respiratory disease. Concentration increases of 10 μg/m3 in NO2, SO2, and PM10 corresponded to 3.90% (95%CI 3.56-4.25), 0.81% (95%CI -0.09-1.72), and 0.64% (95%CI 0.55-0.74) increases in respiratory emergency room visits. In addition, there is a strong synergic effect of PM10 and NO2 on respiratory diseases. The threshold values of the national standard grade II limits used in Beijing should be adjusted. An appropriate standard could effectively promote a significant decline in respiratory room visits and would eventually be beneficial to air quality management in residential areas.

Photocatalytic oxidation of aqueous ammonia over microwave-induced titanate nanotubes.

PubMed

Ou, Hsin-Hung; Liao, Ching-Hui; Liou, Ya-Hsuan; Hong, Jian-Hao; Lo, Shang-Lien

2008-06-15

Characterizations of microwave-induced titanate nanotubes (NaxH(2-x)Ti3O7, TNTs) were conducted by the determinations of specific surface area (S(BET)), X-ray diffraction (XRD), X-ray photoelectron spectroscopic (XPS), ionic coupled plasma-atomic emission spectrometry(ICP-AES), scanning electron microscopy/ energy dispersive X-ray (SEM/EDX), and high-resolution transmission electron microscopy (HR-TEM). The applied level of microwave irradiation during the fabrication process is responsible for both the intercalation intensity of Na atoms into TNTs and the type of crystallization phase within TNTs, which dominate the efficiency of photocatalytic NH3/NH4+. A pure TNT phase presents no powerful ability toward photocatalytic NH3/ NH4+, while the photocatalytic efficiency can be enhanced with the presence of a rutile phase within TNTs. In addition, the mixture of anatase and rutile phase within P25 TiO2 prefers forming NO3-, whereas TNTs yield higher NO2- amount Regarding the effect of acid-washing treatment on TNTs, the acid-treated TNTs with enhanced ion exchangeability considerably improve the NH3/NH4+ degradation and NO2-/NO3- yields. This result is likely ascribed to the easy intercalation of NH3/ NH4+ into the structure of acid-washing TNTs so that the photocatalytic oxidation of intercalated NH3/NH4+ is not limited to the shielding effect resulting from the overload of TNTs.

Seasonal evolution of suspended particles around a large coal-fired power station: Chemical characterization

NASA Astrophysics Data System (ADS)

Querol, Xavier; Alastuey, A´s.; Puicercus, J´A.; Mantilla, Enrique; Ruiz, Carmen R.; Lopez-Soler, Angel; Plana, Felicia`; Juan, Roberto

The present work focuses on the seasonal evolution of total suspended particles (TSP) around the Teruel power station in Northeastern Spain. The results show a marked seasonal trend, along the sampling period (July 1995-July 1996), which is characterized by levels of the elements studied in TSP that were higher (up to one order of magnitude) in spring-summer and decreased progressively towards winter. This trend contrasts with the seasonal evolution reported by most of the studies carried out in industrial and urban areas in Central and Northern Europe. The origin of this seasonal TSP trend may be related to: (a) higher summer oxidation which increased levels of secondary TSP; (b) higher convective circulation in summer which raised levels of soil-related particles and primary anthropogenic particles; (c) higher frequency of intrusion episodes of Sahara air masses in summer and spring; and (d) lower aerosol scavenging potential in summer. A clear grain-size fractionation was observed for the different ions determined. SO 42- and NH 4+ were concentrated in the finest grain-size fraction (0.3-0.6 μm); NO 3-, Cl -, K +, Mg 2+, Na + and minor amounts of NH 4+ were concentrated in the 1.2-5.0 μm fractions; and Ca 2+ increased with the particle diameter. S-bearing species were (NH 4) 2SO 4 (mascagnite), (NH 4) 2Ca(SO 4) 2 · H 2O (koktaite) and CaSO 4 · 2H 2O (gypsum). Mascagnite was the dominant species in the finest grain size fraction (0.3-0.6 μm), whereas koktaite was also present in the 0.6-1.2 μm fraction, and gypsum predominated in the other fractions.

AEROSOL INORGANICS AND ORGANICS MODEL (AIOM) WITH USER DEFINED PROPERTIES FOR ORGANIC COMPOUNDS

EPA Science Inventory

The Aerosol Inorganics Model (AIM) is widely used to calculate gas/liquid/solid phase equilibrium in aerosol systems containing the species H⁺-NH₄⁺-SO₄^2--NO₃^--H₂O over a range of tropospheric ...

Effects of nitrogen with and without acidified sulphur on an ectomycorrhizal community in a Sitka spruce (Picea sitchensis Bong. Carr) forest.

PubMed

Carfrae, J A; Skene, K R; Sheppard, L J; Ingleby, K; Crossley, A

2006-05-01

This preliminary study investigated the effects of enhanced nitrogen (NH4NO3 at 48 kg ha(-1) y(-1)), sulphur (Na2SO4 at 50 kg ha(-1) y(-1)), acidified nitrogen and sulphur (H2SO4 + NH4NO3) at pre-stated doses (pH 2.5), and acidified nitrogen and sulphur deposition at double these doses on the ectomycorrhizal community associated with a 13-year-old Sitka spruce (Picea sitchensis) forest. Sulphur deposition had little impact on below ground ectomycorrhizal diversity, but stimulated sporocarp production. Nitrogen inputs increased below ground colonisation compared to acidified nitrogen and sulphur, largely due to an increase in Tylospora fibrillosa colonisation. Sporocarp production and ectomycorrhizal root colonisation by Lactarius rufus were reduced in the nitrogen treated plots. These observations suggest that nitrogen deposition to a young plantation may suppress ectomycorrhizal fungi producing large sporocarps. It is proposed that enhanced nitrogen deposition increases ectomycorrhizal nitrogen assimilation, consuming more carbon and leaving less for extrametrical mycelium and sporocarp development.

Synthesis, crystal structures and antitumor activities of copper(II) complexes with a 2-acetylpyrazine isonicotinoyl hydrazone ligand

NASA Astrophysics Data System (ADS)

Xu, Jun; Zhou, Tao; Xu, Zhou-Qing; Gu, Xin-Nan; Wu, Wei-Na; Chen, Hong; Wang, Yuan; Jia, Lei; Zhu, Tao-Feng; Chen, Ru-Hua

2017-01-01

Five complexes, [Cu(L)2]·4.5H2O (1), [Cu(HL)2](NO3)2·CH3OH (2) {[Cu2(L)2(NO3)(H2O)2]·(NO3)}n (3), [Cu2(HL)2(SO4)2]·2CH3OH (4) and [Cu4(L)4Cl4]·5H2O (5) based on HL (where HL = 2-acetylpyrazine isonicotinoyl hydrazone) have been synthesized and characterized by X-ray diffraction analyses. The counter anion and organic base during the synthesis procedure influence the structures of the complexes efficiently, which generate five complexes as mono-, bi-, tetra-nuclear and one-dimensional structures. The antitumor activities of the complexes 1-5 (except for complex 3 with the poor solubility) against the Patu8988 human pancreatic cancer, ECA109 human esophagus cancer and SGC7901 human gastric cancer cell lines are screened by MTT assay. The results indicate that the chelation of Cu(II) with the ligand is responsible for the observed high cytotoxicity of the copper(II) complexes and the 1:2 copper species 1 and 2 demonstrate lower antitumor activities than that of the 1:1 copper species 4 and 5. In addition, the in vitro apoptosis inducing activity of the copper(II) complex 5 against SGC7901 cell line is determined. And the results show that the complex can bring about apoptosis of the cancerous cells in vitro.

Preparation, structure and analysis of the bonding in the molecular entity (OSO)2Li{[AlF(ORF)3]Li[Al(ORF)4]} (RF = C(CF3)3).

PubMed

Cameron, T Stanley; Nikiforov, Grigory B; Passmore, Jack; Rautiainen, J Mikko

2010-03-14

The (SO(2))(2)Li[AlF(OR(F))(3)]Li[Al(OR(F))(4)] (1) (R(F) = C(CF(3))(3)) molecular entity was obtained by thermal decomposition of Li[Al(OR(F))(4)] followed by crystallization from liquid SO(2). 1, containing two SO(2) molecules eta(1)-O coordinated to Li(+), was structurally characterized by single crystal X-ray diffraction and NMR spectroscopy in SO(2)(l). Bonding analyses of 1 (bond valency units, AIM analysis, atomic charges, bond orders) show that 1 can be either considered as a Li(OSO)(2)(+) complex stabilized by the large WCA [AlF(OR(F))(3)](-)Li(+)[Al(OR(F))(4)](-) or as consisting of 2 SO(2), 2 Li(+), [AlF(OR(F))(3)](-), and [Al(OR(F))(4)](-) joined by electrostatic interactions into the discrete molecular entity 1. The bonding between Li(+) and SO(2) molecules is shown to be almost completely attributable to monopole-induced dipole electrostatic interactions. Theoretical gas phase lithium ion affinity of SO(2) is determined to be stronger than its silver(I) ion affinity owing largely to the shorter lithium SO(2) contacts in the calculated structures that increase the electrostatic interaction.

Effect of cationic substitution on the double-well hydrogen-bond potential in [K1-x(NH4)x]3H(SO4)2 proton conductors: a single-crystal neutron diffraction study.

PubMed

Choudhury, R R; Chitra, R; Selezneva, E V; Makarova, I P

2017-10-01

The structure of the mixed crystal [K 1-x (NH 4 ) x ] 3 H(SO 4 ) 2 as obtained from single-crystal neutron diffraction is compared with the previously reported room-temperature neutron structure of crystalline K 3 H(SO 4 ) 2 . The two structures are very similar, as indicated by the high value of their isostructurality index (94.8%). It was found that the replacement of even a small amount (3%) of K + with NH 4 + has a significant influence on the short strong hydrogen bond connecting the two SO 4 2- ions. Earlier optical measurements had revealed that the kinetics of the superionic transition in the solid solution [K 1-x (NH 4 ) x ] 3 H(SO 4 ) 2 are much faster than in K 3 H(SO 4 ) 2 ; this reported difference in the kinetics of the superionic phase transition in this class of crystal is explained on the basis of the difference in strength of the hydrogen-bond interactions in the two structures.

[Simulation of air pollution characteristics and estimates of environmental capacity in Zibo City].

PubMed

Xue, Wen-Bo; Wang, Jin-Nan; Yang, Jin-Tian; Lei, Yu; Yan, Li; He, Jin-Yu; Han, Bao-Ping

2013-04-01

To develop a new pattern of air pollution control that is based on the integration of "concentration control, total amount control, and quality control", and in the context of developing national (2011-2015 air pollution control plan for key areas) and (Environmental protection plan of Zibo municipality for the "12th Five-Year Plan" period), a simulation of atmospheric dispersion of air pollutants in Zibo City and its peripheral areas is carried out by employing CALPUFF model, and the atmospheric environmental capacity of SO2, NO(x) and PM10 is estimated based on the results of model simulation and using multi-objective linear programming optimization. The results indicates that the air pollution in Zibo City is significantly related to the pollution sources outside of Zibo City, which contributes to the annual average concentration of SO2, NO2 and PM10 in Zibo City by 26.34%, 21.23%, and 14.58% respectively. There is a notable interaction between districts and counties of Zibo municipality, in which the contribution of SO2, NO(x) and PM10 emissions in surrounding counties and districts to the annual average concentrations of SO2, NO2 and PM10 in downtown area are 35.96%, 43.17%, and 17.69% respectively. There is a great variation in spatial sensitivity of air pollutant emission, and the environmental impact of unit pollutant emissions from Zhoucun, Huantai, Zhangdian and Zichuan is greater than that released from other districts/counties. To meet the requirement of (Ambient air quality standard) (GB 3095-2012), the environmental capacities of SO2, NO(x) and PM10 of Zibo City are only 8.03 x 10(4) t, 19.16 x 10(4) t and 3.21 x 10(4) t, respectively. Therefore, it is imperative to implement regional air pollution joint control in Shandong peninsula in order to ensure the achievement of air quality standard in Zibo City.

Dehydration of glucose to 5-hydroxymethylfurfural by a core-shell Fe3O4@SiO2-SO3H magnetic nanoparticle catalyst

USDA-ARS?s Scientific Manuscript database

This paper discusses the potential use of (Fe3O4@SiO2-SO3H) nanoparticle catalyst for the dehydration of glucose into 5-hydroxymethylfurfural (HMF). A magnetically recoverable (Fe3O4@SiO2-SO3H) nanoparticle catalyst was successfully prepared by supporting sulfonic acid groups (SO3H) on the surface o...

Pediatric emergency department visits and ambient Air pollution in the U.S. State of Georgia: a case-crossover study.

PubMed

Xiao, Qingyang; Liu, Yang; Mulholland, James A; Russell, Armistead G; Darrow, Lyndsey A; Tolbert, Paige E; Strickland, Matthew J

2016-11-25

Estimating the health effects of ambient air pollutant mixtures is necessary to understand the risk of real-life air pollution exposures. Pediatric Emergency Department (ED) visit records for asthma or wheeze (n = 148,256), bronchitis (n = 84,597), pneumonia (n = 90,063), otitis media (n = 422,268) and upper respiratory tract infection (URI) (n = 744,942) were obtained from Georgia hospitals during 2002-2008. Spatially-contiguous daily concentrations of 11 ambient air pollutants were estimated from CMAQ model simulations that were fused with ground-based measurements. Using a case-crossover study design, odds ratios for 3-day moving average air pollutant concentrations were estimated using conditional logistic regression, matching on ZIP code, day-of-week, month, and year. In multipollutant models, the association of highest magnitude observed for the asthma/wheeze outcome was with "oxidant gases" (O 3 , NO 2 , and SO 2 ); the joint effect estimate for an IQR increase of this mixture was OR: 1.068 (95% CI: 1.040, 1.097). The group of "secondary pollutants" (O 3 and the PM 2.5 components SO 4 2- , NO 3- , and NH 4+ ) was strongly associated with bronchitis (OR: 1.090, 95% CI: 1.050, 1.132), pneumonia (OR: 1.085, 95% CI: 1.047, 1.125), and otitis media (OR: 1.059, 95% CI: 1.042, 1.077). ED visits for URI were strongly associated with "oxidant gases," "secondary pollutants," and the "criteria pollutants" (O 3 , NO 2 , CO, SO 2 , and PM 2.5 ). Short-term exposures to air pollution mixtures were associated with ED visits for several different pediatric respiratory diseases.

40 CFR Table B-3 to Subpart B of... - Interferent Test Concentration, 1 Parts per Million

Code of Federal Regulations, 2013 CFR

2013-07-01

... Nitric oxide Carbon dioxide Ethylene Ozone Mxy-lene Water vapor Carbon monoxide Methane Ethane... 4 0.14 750 3 20,000 50 SO2 Gas chromatography 0.1 4 0.14 750 3 20,000 50 SO2 Spectrophotometric-wet... 0.5 3 20,000 SO2 Conductivity 0.2 0.1 4 0.14 0.5 750 SO2 Spectrophotometric-gas phase, including...

Changes in biogeochemical cycling following forest defoliation by pine wilt disease in Kiryu experimental catchment in Japan

NASA Astrophysics Data System (ADS)

Tokuchi, Naoko; Ohte, Nobuhito; Hobara, Satoru; Kim, Su-Jin; Masanori, Katsuyama

2004-10-01

Changes in nutrient budgets and hydrological processes due to the natural disturbance of pine wilt disease (PWD) were monitored in a small, forested watershed in Japan. The disturbance caused changes in soil nitrogen transformations. Pre-disturbance, mineralized nitrogen remained in the form of NH4+, whereas in disturbed areas most mineralized nitrogen was nitrified. Stream NO3- concentrations increased following PWD. There was a delay between time of disturbance and the increase of NO3- in ground and stream waters. Stream concentrations of NO3- and cations (Ca2+ + Mg2+) were significantly correlated from 1994 to 1996, whereas the correlation among NO3-, H+, and SO42- was significant only in 1995. Although both cation exchange and SO42- adsorption buffered protons, cation exchange was the dominant and continuous mechanism for acid buffering. SO42- adsorption was variable and highly pH dependent. The disturbance also resulted in slight delayed changes of input-output nutrient balances. The nitrogen contribution to PWD litter inputs was 7.39 kmol ha-1, and nitrogen loss from streamwater was less than 0.5 kmol ha-1 year-1 throughout the observation period. This large discrepancy suggested substantial nitrogen immobilization.

Densities and apparent molar volumes of atmospherically important electrolyte solutions. 2. The systems H(+)-HSO4(-)-SO4(2-)-H2O from 0 to 3 mol kg(-1) as a function of temperature and H(+)-NH4(+)-HSO4(-)-SO4)2-)-H2O from 0 to 6 mol kg(-1) at 25 °C using a Pitzer ion interaction model, and NH4HSO4-H2O and (NH4)3H(SO4)2-H2O over the entire concentration range.

PubMed

Clegg, S L; Wexler, A S

2011-04-21

A Pitzer ion interaction model has been applied to the systems H(2)SO(4)-H(2)O (0-3 mol kg(-1), 0-55 °C) and H(2)SO(4)-(NH(4))(2)SO(4)-H(2)O (0-6 mol kg(-1), 25 °C) for the calculation of apparent molar volume and density. The dissociation reaction HSO(4)(-)((aq)) ↔ H(+)((aq)) + SO(4)(2-)((aq)) is treated explicitly. Apparent molar volumes of the SO(4)(2-) ion at infinite dilution were obtained from part 1 of this work, (1) and the value for the bisulfate ion was determined in this study from 0 to 55 °C. In dilute solutions of both systems, the change in the degree of dissociation of the HSO(4)(-) ion with concentration results in much larger variations of the apparent molar volumes of the solutes than for conventional strong (fully dissociated) electrolytes. Densities and apparent molar volumes are tabulated. Apparent molar volumes calculated using the model are combined with other data for the solutes NH(4)HSO(4) and (NH(4))(3)H(SO(4))(2) at 25 °C to obtain apparent molar volumes and densities over the entire concentration range (including solutions supersaturated with respect to the salts).

78 FR 22423 - Approval and Promulgation of Air Quality Implementation Plans; West Virginia; The 2002 Base Year...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-16

... (PM 10 ), nitrogen oxides (NO X ), volatile organic compounds (VOC), ammonia (NH 3 ), and sulfur... , coarse particles (PM 10 ), ammonia (NH 3 ), and sulfur dioxide (SO 2 ). [FR Doc. 2013-08835 Filed 4-15-13...

Desert dust,Ocean spray,Volcanoes,Biomass burning: Pathways of nutrients into Andean rainforests

NASA Astrophysics Data System (ADS)

Fabian, P.; Rollenbeck, R.; Spichtinger, N.; Dominguez, G.; Brothers, L.; Thiemens, M.

2009-04-01

Regular rain and fogwater sampling in the Podocarpus National Park, along an altitude profile between 1800 and 3185 m, has been carried out since 2002.The research area located in southern Ecuador on the wet eastern slopes of the Andes is dominated by trade winds from easterly directions. The samples, generally accumulated over 1-week intervals, have been analysed for pH,conductivity and major ions(K+,Na+,NH4+,Ca2+,Mg 2+,SO42-,NO3-,PO43). For all components a strong seasonal variation is observed,while the altitudinal gradient is less pronounced. About 35 % of the weekly samples had very low ion contents,at or below the detection limit, with pH generally above 5 and conductivity below 10 uS/cm.10 days back trajectories (FLEXTRA) showed that respective air masses originated in pristine continental areas,with little or no obvious pollution sources. About 65 %,however,were significantly loaded with cations and anions,with pH often as low as 3.5 to 4.0 and conductivity up to 50 uS/cm.Back trajectories showed that respective air masses had passed over areas of intense biomass burning,volcanoes,and the ocean,with even episodic Sahara and/or Namib desert dust interference. Enhanced SO4 2-and NO3- were identified,by combining satellite-based fire pixels with back trajectories,as predominantly resulting from biomass burning. Analyses of oxygen isotopes 16O ,17O ,and 18O of nitrate show that nitrate in fog samples is a product of atmospheric conversion of precursors.For most cases,by using emission inventories, anthropogenic precursor sources other than forest fires could be ruled out,thus leaving biomass burning as the main source of nitrate and sulphate in rain and fogwater. Some SO4 2- ,about 10 % of the total input,could be identified to originate from active volcanoes, whose plumes were sometimes encountered by the respective back trajectories. Enhanced Na +, K + ,and Cl - was found to originate from ocean spray sources.They were associated with strong winds providing Atlantic air masses to reach the receptor site within less than 5 days.Episodes of enhanced Ca 2+ and Mg 2+ were found to be associated with air masses from African deserts.Satellite aerosol data clearly confirmed desert sources both on the Northern (Sahara) as on the Southern Hemisphere (Namib),depending on season. Few episodes of distinct PO43-deposition are due to air masses either from north African (phosphate mining) or coastal sites of Peru (guano?). While volcanic,oceanic and desert sources are natural, large scale biomass burning is an anthropogenic source which adds about 7 kg/ha of NO3- and 14 kg/ha of SO4 2- per year .The episodic PO4 3- deposition amounts to about 2.6 kg/ha PO4 3- per year.Controlled fertilizing experiments are presently carried out to investigate the impact of these disturbances on the mountain forest ecosystem.

Warm-Up Exercises May Not Be So Important for Enhancing Submaximal Running Performance.

PubMed

Takizawa, Kazuki; Yamaguchi, Taichi; Shibata, Keisuke

2018-05-01

Takizawa, K, Yamaguchi, T, and Shibata, K. Warm-up exercises may not be so important for enhancing submaximal running performance. J Strength Cond Res 32(5): 1383-1390, 2018-The purpose of this study was to determine an appropriate warm-up intensity for enhancing performance in submaximal running at 90% vV[Combining Dot Above]O2max (it assumes 3,000-5,000 m in track events). Seven trained male university athletes took part in this study (age: 21.3 ± 2.1 years, height: 169.3 ± 4.7 cm, body mass: 58.4 ± 5.6 kg, V[Combining Dot Above]O2max: 73.33 ± 5.46 ml·kg·min). Each subject ran on a treadmill at 90% vV[Combining Dot Above]O2max until exhaustion after 1 of 4 warm-up treatments. The 4 warm-up treatments were no warm-up, 15 minutes running at 60% vV[Combining Dot Above]O2max, at 70% vV[Combining Dot Above]O2max, and at 80% vV[Combining Dot Above]O2max. The running performance was evaluated by time to exhaustion (TTE). V[Combining Dot Above]O2, and vastus lateralis muscle temperature were also measured. There were no significant differences in TTE among the warm-up exercises (p > 0.05). V[Combining Dot Above]O2 in no warm-up showed slower reaction than the other warm-up exercises. Regarding, the vastus lateralis muscle temperature immediately after warm-up, no warm-up was significantly (p < 0.01) lower compared with the other warm-up exercises. Our results suggested that submaximal running performance was not affected by the presence or absence of a warm-up or by warm-up intensity, although physiological changes occurred.

Photocrystallographic structure determination of a new geometric isomer of [Ru(NH3)4(H2O)(eta1-OSO)][MeC6H4SO3]2.

PubMed

Bowes, Katharine F; Cole, Jacqueline M; Husheer, Shamus L G; Raithby, Paul R; Savarese, Teresa L; Sparkes, Hazel A; Teat, Simon J; Warren, John E

2006-06-21

The structure of a new metastable geometric isomer of [Ru(NH3)4(H2O)(SO2)][MeC6H4SO3]2 in which the SO2 group is coordinated through a single oxygen in an eta1-OSO bonding mode has been determined at 13 K; the new isomer was obtained as a 36% component of the structure within a single crystal upon irradiation using a tungsten lamp.