46 CFR 153.1046 - Sulfuric acid.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 5 2011-10-01 2011-10-01 false Sulfuric acid. 153.1046 Section 153.1046 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING BULK....1046 Sulfuric acid. No person may liquefy frozen or congealed sulfuric acid other than by external tank...

Heterogeneous Interactions of Acetaldehyde and Sulfuric Acid

NASA Technical Reports Server (NTRS)

Michelsen, R. R.; Ashbourn, S. F. M.; Iraci, L. T.

2004-01-01

The uptake of acetaldehyde [CH3CHO] by aqueous sulfuric acid has been studied via Knudsen cell experiments over ranges of temperature (210-250 K) and acid concentration (40-80 wt. %) representative of the upper troposphere. The Henry's law constants for acetaldehyde calculated from these data range from 6 x 10(exp 2) M/atm for 40 wt. % H2SO4 at 228 K to 2 x 10(exp 5) M/atm for 80 wt. % H2SO4 at 212 K. In some instances, acetaldehyde uptake exhibits apparent steady-state loss. The possible sources of this behavior, including polymerization, will be explored. Furthermore, the implications for heterogeneous reactions of aldehydes in sulfate aerosols in the upper troposphere will be discussed.

Radiolysis of Sulfuric Acid, Sulfuric Acid Monohydrate, and Sulfuric Acid Tetrahydrate and Its Relevance to Europa

NASA Technical Reports Server (NTRS)

Loeffler, M. J.; Hudson, R. L.; Moore, M. H.; Carlson, R. W.

2011-01-01

We report laboratory studies on the 0.8 MeV proton irradiation of ices composed of sulfuric acid (H2SO4), sulfuric acid monohydrate (H2SO4 H2O), and sulfuric acid tetrahydrate (H2SO4 4H2O) between 10 and 180 K. Using infrared spectroscopy, we identify the main radiation products as H2O, SO2, (S2O3)x, H3O+, HSO4(exp -), and SO4(exp 2-). At high radiation doses, we find that H2SO4 molecules are destroyed completely and that H2SO4 H2O is formed on subsequent warming. This hydrate is significantly more stable to radiolytic destruction than pure H2SO4, falling to an equilibrium relative abundance of 50% of its original value on prolonged irradiation. Unlike either pure H2SO4 or H2SO4 H2O, the loss of H2SO4 4H2O exhibits a strong temperature dependence, as the tetrahydrate is essentially unchanged at the highest irradiation temperatures and completely destroyed at the lowest ones, which we speculate is due to a combination of radiolytic destruction and amorphization. Furthermore, at the lower temperatures it is clear that irradiation causes the tetrahydrate spectrum to transition to one that closely resembles the monohydrate spectrum. Extrapolating our results to Europa s surface, we speculate that the variations in SO2 concentrations observed in the chaotic terrains are a result of radiation processing of lower hydration states of sulfuric acid and that the monohydrate will remain stable on the surface over geological times, while the tetrahydrate will remain stable in the warmer regions but be destroyed in the colder regions, unless it can be reformed by other processes, such as thermal reactions induced by diurnal cycling.

Effect of Sulfuric Acid on the Uptake of Sulfur Dioxide on Soot

NASA Astrophysics Data System (ADS)

Slowik, J. G.; Koehler, B. G.

2001-05-01

The uptake of SO2 on soot may lead to the formation of sulfuric acid on the soot. The sulfuric acid then can affect the further uptake of SO2 on the soot. We are interested in the effect of submonolayer H2SO4 on the uptake of SO2. We measured the uptake of SO2 on n-hexane soot as a function SO2 pressure (10-7 to 10-4 Torr) and sulfuric acid coverage between -140\\deg and -120\\deg C. We generate sulfuric acid by adsorbing varying amounts of SO3 on soot, covering the SO3 with a thick layer of condensed H2O, and heating to 193 K to react the SO3 and H2O and to remove the excess H2O. The sulfuric acid coverage is in the range of monolayer or sub-monolayer. Adsorption of SO2 on soot with and without the sulfuric acid shows that the acid reduces the SO2 uptake by a factor of two or more. Varying the amount of acid has little effect on uptake. However, increasing the thickness of the soot substrate causes a significant increase in SO2 uptake.

Aqueous process for recovering sulfur from hydrogen sulfide-bearing gas

DOEpatents

Basu, Arunabha

2015-05-05

A process for recovering sulfur from a hydrogen sulfide-bearing gas utilizes an aqueous reaction medium, a temperature of about 110-150.degree. C., and a high enough pressure to maintain the aqueous reaction medium in a liquid state. The process reduces material and equipment costs and addresses the environmental disadvantages associated with known processes that rely on high boiling point organic solvents.

Sulfuric acid in the Venus clouds.

NASA Technical Reports Server (NTRS)

Sill, G. T.

1972-01-01

The extremely dry nature of the Venus upper atmosphere appears to demand the presence of an efficient desiccating agent as the chief constituent of the clouds of Venus. On the basis of polarization measures it is to be expected that this substance is present as spherical droplets, 1 to 2 microns in diameter, with a refractive index n of 1.46 plus or minus 0.02 at 3500A in the observed region of the atmosphere, with T about equal to 235 K. This substance must have ultraviolet, visible, and infrared reflection properties not inconsistent with the observed spectrum of Venus. Sulfuric acid, of about 86% by weight composition, roughly fulfills the first of these properties. The visible and ultraviolet transmission features of a thin layer of elemental bromine and hydrobromic acid dissolved in sulfuric acid somewhat resemble the Venus spectrum, up to 14 microns. The chemical process postulated for forming sulfuric acid involves the oxidation of sulfur and its compounds to sulfuric acid through the agency of elemental bromine produced by the photolytic decomposition of hydrogen bromide.

Growth of nitric acid hydrates on thin sulfuric acid films

NASA Technical Reports Server (NTRS)

Iraci, Laura T.; Middlebrook, Ann M.; Wilson, Margaret A.; Tolbert, Margaret A.

1994-01-01

Type I polar stratospheric clouds (PSCs) are thought to nucleate and grow on stratospheric sulfate aerosols (SSAs). To model this system, thin sulfuric acid films were exposed to water and nitric acid vapors (1-3 x 10(exp -4) Torr H2O and 1-2.5 x 10(exp -6) Torr HNO3) and subjected to cooling and heating cycles. Fourier Transform Infrared (FTIR) spectroscopy was used to probe the phase of the sulfuric acid and to identify the HNO3/H2O films that condensed. Nitric acid trihydrate (NAT) was observed to grow on crystalline sulfuric acid tetrahydrate (SAT) films. NAT also condensed in/on supercooled H2SO4 films without causing crystallization of the sulfuric acid. This growth is consistent with NAT nucleation from ternary solutions as the first step in PSC formation.

Decomposition mechanism of chromite in sulfuric acid-dichromic acid solution

NASA Astrophysics Data System (ADS)

Zhao, Qing; Liu, Cheng-jun; Li, Bao-kuan; Jiang, Mao-fa

2017-12-01

The sulfuric acid leaching process is regarded as a promising, cleaner method to prepare trivalent chromium products from chromite; however, the decomposition mechanism of the ore is poorly understood. In this work, binary spinels of Mg-Al, Mg-Fe, and Mg-Cr in the powdered and lump states were synthesized and used as raw materials to investigate the decomposition mechanism of chromite in sulfuric acid-dichromic acid solution. The leaching yields of metallic elements and the changes in morphology of the spinel were studied. The experimental results showed that the three spinels were stable in sulfuric acid solution and that dichromic acid had little influence on the decomposition behavior of the Mg-Al spinel and Mg-Fe spinel because Mg2+, Al3+, and Fe3+ in spinels cannot be oxidized by Cr6+. However, in the case of the Mg-Cr spinel, dichromic acid substantially promoted the decomposition efficiency and functioned as a catalyst. The decomposition mechanism of chromite in sulfuric acid-dichromic acid solution was illustrated on the basis of the findings of this study.

A comparison of chromic acid and sulfuric acid anodizing

NASA Technical Reports Server (NTRS)

Danford, M. D.

1992-01-01

Because of federal and state mandates restricting the use of hexavalent chromium, it was deemed worthwhile to compare the corrosion protection afforded 2219-T87 aluminum alloy by both Type I chromic acid and Type II sulfuric acid anodizing per MIL-A-8625. Corrosion measurements were made on large, flat 2219-T87 aluminum alloy sheet material with an area of 1 cm(exp 2) exposed to a corrosive medium of 3.5-percent sodium chloride at pH 5.5. Both ac electrochemical impedance spectroscopy and the dc polarization resistance techniques were employed. The results clearly indicate that the corrosion protection obtained by Type II sulfuric acid anodizing is superior, and no problems should result by substituting Type II sulfuric acid anodizing for Type I chromic acid anodizing.

Process for forming sulfuric acid

DOEpatents

Lu, Wen-Tong P.

1981-01-01

An improved electrode is disclosed for the anode in a sulfur cycle hydrogen generation process where sulfur dioxie is oxidized to form sulfuric acid at the anode. The active compound in the electrode is palladium, palladium oxide, an alloy of palladium, or a mixture thereof. The active compound may be deposited on a porous, stable, conductive substrate.

Molecular Modeling of Ammonium, Calcium, Sulfur, and Sodium Lignosulphonates in Acid and Basic Aqueous Environments

NASA Astrophysics Data System (ADS)

Salazar Valencia, P. J.; Bolívar Marinez, L. E.; Pérez Merchancano, S. T.

2015-12-01

Lignosulphonates (LS), also known as lignin sulfonates or sulfite lignin, are lignins in sulfonated forms, obtained from the "sulfite liquors," a residue of the wood pulp extraction process. Their main utility lies in its wide range of properties, they can be used as additives, dispersants, binders, fluxing, binder agents, etc. in fields ranging from food to fertilizer manufacture and even as agents in the preparation of ion exchange membranes. Since they can be manufactured relatively easy and quickly, and that its molecular size can be manipulated to obtain fragments of very low molecular weight, they are used as transport agents in the food industry, cosmetics, pharmaceutical and drug development, and as molecular elements for the treatment of health problems. In this paper, we study the electronic structural and optical characteristics of LS incorporating ammonium, sulfur, calcium, and sodium ions in acidic and basic aqueous media in order to gain a better understanding of their behavior and the very interesting properties exhibit. The studies were performed using the molecular modeling program HyperChem 5 using the semiempirical method PM3 of the NDO Family (neglect of differential overlap), to calculate the structural properties. We calculated the electronic and optical properties using the semiempirical method ZINDO / CI.

Mass accommodation coefficient measurements for HNO3, HCl and N2O5 on water, ice and aqueous sulfuric acid droplet surfaces

NASA Technical Reports Server (NTRS)

Worsnop, Douglas; Zahniser, Mark; Kolb, Charles; Watson, Lyn; Vandoren, Jane; Jayne, John; Davidovits, Paul

1988-01-01

Preliminary results are reported of the direct measurement of accommodation coefficients for HNO3, N2O5 and HCl on water drops, aqueous sulfuric acid drops and ice particles. The heterogeneous chemistry of these species together with ClONO2 has been implicated in the ozone depletion observed in the Antarctic stratosphere during the spring in the last eight years. The most plausible chemical mechanism involves the removal of nitrogen oxide species via condensation on ice particles in polar stratospheric clouds resulting in a increase in the active chlorine species responsible for the ozone depletion. The observation of low NO2 and high ClO densities in the Antarctic stratosphere last summer appear to be consistent with such a mechanism.

CESIUM RECOVERY FROM AQUEOUS SOLUTIONS

DOEpatents

Schneider, R.A.

1961-06-20

Cesium may be precipitated from an aqueous solution whose acidity ranges between a pH of 1.5 and a molarity of 5 on cobaltous, zinc, cadmium, nickel, or ferrous cobalticyanide. This precipitation brings about a separation from most fission products. Ruthenium which coprecipitates to a great degree can be removed by dissolving in sulfuric acid and boiling the solution in the presence of periodic acid for volatilization; other coprecipitated fission products can then be precipitated from the sulfuric acid solution with a ferric hydroxide carrier.

Chemical trapping and characterization of small oxoacids of sulfur (SOS) generated in aqueous oxidations of H2S.

PubMed

Kumar, Murugaeson R; Farmer, Patrick J

2018-04-01

Small oxoacids of sulfur (SOS) are elusive molecules like sulfenic acid, HSOH, and sulfinic acid, HS(O)OH, generated during the oxidation of hydrogen sulfide, H 2 S, in aqueous solution. Unlike their alkyl homologs, there is a little data on their generation and speciation during H 2 S oxidation. These SOS may exhibit both nucleophilic and electrophilic reactivity, which we attribute to interconversion between S(II) and S(IV) tautomers. We find that SOS may be trapped in situ by derivatization with nucleophilic and electrophilic trapping agents and then characterized by high resolution LC MS. In this report, we compare SOS formation from H 2 S oxidation by a variety of biologically relevant oxidants. These SOS appear relatively long lived in aqueous solution, and thus may be involved in the observed physiological effects of H 2 S. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Nitric acid uptake by sulfuric acid solutions under stratospheric conditions - Determination of Henry's Law solubility

NASA Technical Reports Server (NTRS)

Reihs, Christa M.; Golden, David M.; Tolbert, Margaret A.

1990-01-01

The uptake of nitric acid by sulfuric acid solutions representative of stratospheric particulate at low temperatures was measured to determine the solubility of nitric acid in sulfuric acid solutions as a function of H2SO4 concentration and solution temperature. Solubilities are reported for sulfuric acid solutions ranging from 58 to 87 wt pct H2SO4 over a temperature range from 188 to 240 K, showing that, in general, the solubility of nitric acid increases with decreasing sulfuric acid concentration and with decreasing temperature. The measured solubilities indicate that nitric acid in the global stratosphere will be found predominantly in the gas phase.

Characterization of sulfur oxidizing bacteria related to biogenic sulfuric acid corrosion in sludge digesters.

PubMed

Huber, Bettina; Herzog, Bastian; Drewes, Jörg E; Koch, Konrad; Müller, Elisabeth

2016-07-18

Biogenic sulfuric acid (BSA) corrosion damages sewerage and wastewater treatment facilities but is not well investigated in sludge digesters. Sulfur/sulfide oxidizing bacteria (SOB) oxidize sulfur compounds to sulfuric acid, inducing BSA corrosion. To obtain more information on BSA corrosion in sludge digesters, microbial communities from six different, BSA-damaged, digesters were analyzed using culture dependent methods and subsequent polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE). BSA production was determined in laboratory scale systems with mixed and pure cultures, and in-situ with concrete specimens from the digester headspace and sludge zones. The SOB Acidithiobacillus thiooxidans, Thiomonas intermedia, and Thiomonas perometabolis were cultivated and compared to PCR-DGGE results, revealing the presence of additional acidophilic and neutrophilic SOB. Sulfate concentrations of 10-87 mmol/L after 6-21 days of incubation (final pH 1.0-2.0) in mixed cultures, and up to 433 mmol/L after 42 days (final pH <1.0) in pure A. thiooxidans cultures showed huge sulfuric acid production potentials. Additionally, elevated sulfate concentrations in the corroded concrete of the digester headspace in contrast to the concrete of the sludge zone indicated biological sulfur/sulfide oxidation. The presence of SOB and confirmation of their sulfuric acid production under laboratory conditions reveal that these organisms might contribute to BSA corrosion within sludge digesters. Elevated sulfate concentrations on the corroded concrete wall in the digester headspace (compared to the sludge zone) further indicate biological sulfur/sulfide oxidation in-situ. For the first time, SOB presence and activity is directly relatable to BSA corrosion in sludge digesters.

Mechanisms of volatile production from non-sulfur amino acids by irradiation

NASA Astrophysics Data System (ADS)

Ahn, Dong Uk; Lee, Eun Joo; Feng, Xi; Zhang, Wangang; Lee, Ji Hwan; Jo, Cheorun; Nam, Kichang

2016-02-01

Non-sulfur amino acid monomers were used to study the mechanisms of volatile production in meat by irradiation. Irradiation not only produced many volatiles but also increased the amounts of volatiles from non-sulfur amino acid monomers. The major reaction mechanisms involved in volatile production from each group of the amino acids by irradiation differ significantly. However, we speculate that the radiolysis of amino acid side chains were the major mechanism. In addition, Strecker degradation, especially the production of aldehydes from aliphatic group amino acids, and deamination, isomerization, decarboxylation, cyclic reaction and dehydrogenation of the initial radiolytic products were also contributed to the production of volatile compounds. Each amino acid monomers produced different odor characteristics, but the intensities of odor from all non-sulfur amino acid groups were very weak. This indicated that the contribution of volatiles produced from non-sulfur amino acids was minor. If the volatile compounds from non-sulfur amino acids, especially aldehydes, interact with other volatiles compounds such as sulfur compounds, however, they can contribute to the off-odor of irradiated meat significantly.

Sulfuric acid induces airway hyperresponsiveness to substance P in the guinea pig.

PubMed

Stengel, P W; Bendele, A M; Cockerham, S L; Silbaugh, S A

1993-01-01

We investigated whether sulfuric acid inhalation would cause hyperresponsiveness to substance P. Guinea pigs became dyspneic during a 1 h sulfuric acid exposure, but recovered by 24 h when they were challenged with substance P or histamine aerosols. Eight minutes after the start of challenge, animals were killed and excised lung gas volumes measured. Sulfuric acid slightly increased histamine responsiveness compared to controls. However, sulfuric acid caused a much more pronounced leftward shift in the dose response to substance P. Coadministration of the neutral endopeptidase (NEP) inhibitor, thiorphan, did not reduce sulfuric acid-related hyperresponsiveness to substance P. By 72 h, sensitization to substance P was absent. Histological evaluation of sulfuric acid-treated lungs revealed mild alveolitis at 24 h, but not at 72 h. We conclude that sulfuric acid produces a marked sensitization to substance P. Inactivation of NEP does not appear to account for this effect.

Heterogeneous Interaction of Peroxyacetyl Nitrate on Liquid Sulfuric Acid

NASA Technical Reports Server (NTRS)

Zhang, Renyi; Leu, Ming-Taun

1996-01-01

The uptake of peroxyacetyl nitrate (PAN) on liquid sulfuric acid surfaces has been investigated using a fast-flow reactor coupled to a chemical ionization mass spectrometer. PAN was observed to be reversibly adsorbed on sulfuric acid.

The corrosion protection of several aluminum alloys by chromic acid and sulfuric acid anodizing

NASA Technical Reports Server (NTRS)

Danford, M. D.

1994-01-01

The corrosion protection afforded 7075-T6, 7075-T3, 6061-T6, and 2024-T3 aluminum alloys by chromic acid and sulfuric acid anodizing was examined using electrochemical techniques. From these studies, it is concluded that sulfuric acid anodizing provides superior corrosion protection compared to chromic acid anodizing.

SEPARATION OF PLUTONIUM FROM AQUEOUS SOLUTIONS BY ION-EXCHANGE

DOEpatents

Schubert, J.

1958-06-01

A process is described for the separation of plutonium from an aqueous solution of a plutonium salt, which comprises adding to the solution an acid of the group consisting of sulfuric acid, phosphoric acid, and oxalic acid, and mixtures thereof to provide an acid concentration between 0.0001 and 1 M, contacting the resultant solution with a synthetic organic anion exchange resin, and separating the aqueous phase and the resin which contains the plutonium.

Thin-film sulfuric acid anodizing as a replacement for chromic acid anodizing

NASA Technical Reports Server (NTRS)

Kallenborn, K. J.; Emmons, J. R.

1995-01-01

Chromic acid has long been used to produce a thin, corrosion resistant (Type I) coating on aluminum. Following anodizing, the hardware was sealed using a sodium dichromate solution. Sealing closes up pores inherent in the anodized coating, thus improving corrosion resistance. The thinness of the brittle coating is desirable from a fatigue standpoint, and chromium was absorbed by the coating during the sealing process, further improving corrosion resistance. Unfortunately, both chromic acid and sodium dichromate contain carcinogenic hexavalent chromium. Sulfuric acid is being considered as a replacement for chromic acid. Sulfuric acid of 10-20 percent concentration has traditionally been used to produce relatively thick (Types II and III) or abrasion resistant (Type III) coatings. A more dilute, that is five weight percent, sulfuric acid anodizing process, which produces a thinner coating than Type II or III, with nickel acetate as the sealant has been developed. The process was evaluated in regard to corrosion resistance, throwing power, fatigue life, and processing variable sensitivity, and shows promise as a replacement for the chromic acid process.

Heterogeneous Chemistry of HONO on Liquid Sulfuric Acid: A New Mechanism of Chlorine Activation on Stratospheric Sulfate Aerosols

NASA Technical Reports Server (NTRS)

Zhang, Renyi; Leu, Ming-Taun; Keyser, Leon F.

1996-01-01

Heterogeneous chemistry of nitrous acid (HONO) on liquid sulfuric acid (H2SO4) Was investigated at conditions that prevail in the stratosphere. The measured uptake coefficient (gamma) of HONO on H2SO4 increased with increasing acid content, ranging from 0.03 for 65 wt % to about 0.1 for 74 wt %. In the aqueous phase, HONO underwent irreversible reaction with H2SO4 to form nitrosylsulfuric acid (NO(+)HSO4(-). At temperatures below 230 K, NO(+)HSO4(-) was observed to be stable and accumulated in concentrated solutions (less than 70 wt % H2SO4) but was unstable and quickly regenerated HONO in dilute solutions (less than 70 wt %). HCl reacted with HONO dissolved in sulfuric acid, releasing gaseous nitrosyl chloride (ClNO). The reaction probability between HCl and HONO varied from 0.01 to 0.02 for 60-72 wt % H2SO4. In the stratosphere, ClNO photodissociates rapidly to yield atomic chlorine, which catalytically destroys ozone. Analysis of the laboratory data reveals that the reaction of HCl with HONO on sulfate aerosols can affect stratospheric ozone balance during elevated sulfuric acid loadings after volcanic eruptions or due to emissions from the projected high-speed civil transport (HSCT). The present results may have important implications on the assessment of environmental acceptability of HSCT.

Solubility of acetic acid and trifluoroacetic acid in low-temperature (207-245 k) sulfuric acid solutions: implications for the upper troposphere and lower stratosphere.

PubMed

Andersen, Mads P Sulbaek; Axson, Jessica L; Michelsen, Rebecca R H; Nielsen, Ole John; Iraci, Laura T

2011-05-05

The solubility of gas-phase acetic acid (CH(3)COOH, HAc) and trifluoroacetic acid (CF(3)COOH, TFA) in aqueous sulfuric acid solutions was measured in a Knudsen cell reactor over ranges of temperature (207-245 K) and acid composition (40-75 wt %, H(2)SO(4)). For both HAc and TFA, the effective Henry's law coefficient, H*, is inversely dependent on temperature. Measured values of H* for TFA range from 1.7 × 10(3) M atm(-1) in 75.0 wt % H(2)SO(4) at 242.5 K to 3.6 × 10(8) M atm(-1) in 40.7 wt % H(2)SO(4) at 207.8 K. Measured values of H* for HAc range from 2.2 × 10(5) M atm(-1) in 57.8 wt % H(2)SO(4) at 245.0 K to 3.8 × 10(8) M atm(-1) in 74.4 wt % H(2)SO(4) at 219.6 K. The solubility of HAc increases with increasing H(2)SO(4) concentration and is higher in strong sulfuric acid than in water. In contrast, the solubility of TFA decreases with increasing sulfuric acid concentration. The equilibrium concentration of HAc in UT/LS aerosol particles is estimated from our measurements and is found to be up to several orders of magnitude higher than those determined for common alcohols and small carbonyl compounds. On the basis of our measured solubility, we determine that HAc in the upper troposphere undergoes aerosol partitioning, though the role of H(2)SO(4) aerosol particles as a sink for HAc in the upper troposphere and lower stratosphere will only be discernible under high atmospheric sulfate perturbations.

Sulfur and Hydrogen Isotope Anomalies in Meteorite Sulfonic Acids

NASA Technical Reports Server (NTRS)

Cooper, George W.; Thiemens, Mark H.; Jackson, Teresa L.; Chang, Sherwood

1997-01-01

Intramolecular carbon, hydrogen, and sulfur isotope ratios were measured on a homologous series of organic sulfonic acids discovered in the Murchison meteorite. Mass-independent sulfur isotope fractionations were observed along with high deuterium/hydrogen ratios. The deuterium enrichments indicate formation of the hydrocarbon portion of these compounds in a low-temperature environment that is consistent with that of interstellar clouds. Sulfur-33 enrichments observed in methanesulfonic acid could have resulted from gas-phase ultraviolet irradiation of a precursor, carbon disulfide. The source of the sulfonic acid precursors may have been the reactive interstellar molecule carbon monosulfide.

Synthesis and characterization of an anomeric sulfur analogue of CMP-sialic acid.

PubMed

Cohen, S B; Halcomb, R L

2000-09-22

alpha-2,3-Sialyltransferase catalyzes the transfer of sialic acid from CMP-sialic acid (1) to a lactose acceptor. An analogue of 1 was synthesized in which the anomeric oxygen atom was replaced with a sulfur atom (1S). The key step in the synthesis of 1S was a tetrazole-promoted coupling of a cytidine-5'-phosphoramidite with a glycosyl thiol of a protected sialic acid. Compounds 1 and 1S were characterized for their activity in a sialyl transfer assay. The rate of solvolysis in aqueous buffer of analogue 1S was 50-fold slower than that of 1. Analogue 1S was found to be substrate for alpha-2,3-sialyltransferase. The K(m) of 1S was just 3-fold higher than that of 1, while the k(cat) of 1S was 2 orders of magnitude lower compared to 1.

Kinetics and mechanism of hydration of o-thioquinone methide in aqueous solution. Rate-determining protonation of sulfur.

PubMed

Chiang, Yvonne; Kresge, A Jerry; Sadovski, Oleg; Zhan, Hao-Qiang

2005-03-04

o-Thioquinone methide, 2, was generated in aqueous solution by flash photolysis of benzothiete, 1, and rates of hydration of this quinone methide to o-mercaptobenzyl alcohol, 3, were measured in perchloric acid solutions, using H2O and D2O as the solvent, and also in acetic acid and tris(hydroxymethyl)methylammonium ion buffers, using H2O as the solvent. The rate profiles constructed from these data show hydronium-ion-catalyzed and uncatalyzed hydration reaction regions, just like the rate profiles based on literature data for hydration of the oxygen analogue, o-quinone methide, of the presently examined substrate. Solvent isotope effects on hydronium-ion catalysis of hydration for the two substrates, however, are quite different: k(H)/k(D) = 0.42 for the oxygen quinone methide, whereas k(H)/k(D) = 1.66 for the sulfur substrate. The inverse nature (k(H)/k(D) < 1) of the isotope effect in the oxygen system indicates that this reaction occurs by a preequilibrium proton-transfer reaction mechanism, with protonation of the substrate on its oxygen atom being fast and reversible and capture of the benzyl-type carbocationic intermediate so formed being rate-determining. The normal direction (k(H)/k(D) > 1) of the isotope effect in the sulfur system, on the other hand, suggests that protonation of the substrate on its sulfur atom is in this case rate-determining, with carbocation capture a fast following step. A semiquantitative argument supporting this hypothesis is presented.

Quantitative Chromatographic Determination of Dissolved Elemental Sulfur in the Non-aqueous Electrolyte for Lithium-Sulfur Batteries

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

Zheng, Dong; Yang, Xiao-Qing; Zhang, Xuran

A fast and reliable analytical method is reported for the quantitative determination of dissolved elemental sulfur in non-aqueous electrolytes for Li-S batteries. By using high performance liquid chromatography with a UV detector, the solubility of S in 12 different pure solvents and in 22 different electrolytes was determined. It was found that the solubility of elemental sulfur is dependent on the Lewis basicity, the polarity of solvents and the salt concentration in the electrolytes. In addition, the S content in the electrolyte recovered from a discharged Li-S battery was successfully determined by the proposed HPLC/UV method. Thus, the feasibility ofmore » the method to the online analysis for a Li-S battery is demonstrated. Interestingly, the S was found super-saturated in the electrolyte recovered from a discharged Li-S cell.« less

Quantitative Chromatographic Determination of Dissolved Elemental Sulfur in the Non-aqueous Electrolyte for Lithium-Sulfur Batteries

DOE PAGES

Zheng, Dong; Yang, Xiao-Qing; Zhang, Xuran; ...

2014-12-02

A fast and reliable analytical method is reported for the quantitative determination of dissolved elemental sulfur in non-aqueous electrolytes for Li-S batteries. By using high performance liquid chromatography with a UV detector, the solubility of S in 12 different pure solvents and in 22 different electrolytes was determined. It was found that the solubility of elemental sulfur is dependent on the Lewis basicity, the polarity of solvents and the salt concentration in the electrolytes. In addition, the S content in the electrolyte recovered from a discharged Li-S battery was successfully determined by the proposed HPLC/UV method. Thus, the feasibility ofmore » the method to the online analysis for a Li-S battery is demonstrated. Interestingly, the S was found super-saturated in the electrolyte recovered from a discharged Li-S cell.« less

Aqueous solutions of acidic ionic liquids for enhanced stability of polyoxometalate-carbon supercapacitor electrodes

NASA Astrophysics Data System (ADS)

Hu, Chenchen; Zhao, Enbo; Nitta, Naoki; Magasinski, Alexandre; Berdichevsky, Gene; Yushin, Gleb

2016-09-01

Nanocomposites based on polyoxometalates (POMs) nanoconfined in microporous carbons have been synthesized and used as electrodes for supercapacitors. The addition of the pseudocapacitance from highly reversible redox reaction of POMs to the electric double-layer capacitance of carbon lead to an increase in specific capacitance of ∼90% at 1 mV s-1. However, high solubility of POM in traditional aqueous electrolytes leads to rapid capacity fading. Here we demonstrate that the use of aqueous solutions of protic ionic liquids (P-IL) as electrolyte instead of aqueous sulfuric acid solutions offers an opportunity to significantly improve POM cycling stability. Virtually no degradation in capacitance was observed in POM-based positive electrode after 10,000 cycles in an asymmetric capacitor with P-IL aqueous electrolyte. As such, POM-based carbon composites may now present a viable solution for enhancing energy density of electrical double layer capacitors (EDLC) based on pure carbon electrodes.

SULFURIC ACID RAIN EFFECTS ON CROP YIELD AND FOLIAR INJURY

EPA Science Inventory

A study was undertaken to determine the relative sensitivity of major U.S. crops to sulfuric acid rain. Plants were grown under controlled environmental conditions and exposed to simulated acid rain of three sulfuric acid concentrations (pH 3.0, 3.5, 4.0) or to a control rain (pH...

Characterization of a transient +2 sulfur oxidation state intermediate from the oxidation of aqueous sulfide

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

Vairavmurthy, M.A.; Zhou, Weiqing

1995-04-01

The oxidation H{sub 2}S to sulfate involves a net transfer of eight electrons and occurs through the formation of several partially oxidized intermediates with oxidation states ranging from {minus}1 to +5. Known intermediates include elemental sulfur (oxidation state 0), polysulfides (outer sulfur: {minus}1, inner sulfur: 0), sulfite (+4) and thiosulfate (outer sulfur: {minus}1, inner sulfur: +5). A noticeable gap in this series of intermediates is that of a +2 sulfur oxidation state oxoacid/oxoanion species, which was never detected experimentally. Here, we present evidence of the transient existence of +2 oxidation state intermediate in the Ni(II)-catalyzed oxidation of aqueous sulfide. X-raymore » absorption near-edge structure (XANES) spectroscopy and Fourier-transform-infrared (FT-IR) spectroscopy were used to characterize this species; they suggest that it has a sulfoxylate ion (SO{sub 2}{sup 2{minus}}) structure.« less

Effects of Precursor Concentration and Acidic Sulfate in Aqueous Glyoxal−OH Radical Oxidation and Implications for Secondary Organic Aerosol

PubMed Central

2009-01-01

Previous experiments demonstrated that aqueous OH radical oxidation of glyoxal yields low-volatility compounds. When this chemistry takes place in clouds and fogs, followed by droplet evaporation (or if it occurs in aerosol water), the products are expected to remain partially in the particle phase, forming secondary organic aerosol (SOA). Acidic sulfate exists ubiquitously in atmospheric water and has been shown to enhance SOA formation through aerosol phase reactions. In this work, we investigate how starting concentrations of glyoxal (30−3000 μM) and the presence of acidic sulfate (0−840 μM) affect product formation in the aqueous reaction between glyoxal and OH radical. The oxalic acid yield decreased with increasing precursor concentrations, and the presence of sulfuric acid did not alter oxalic acid concentrations significantly. A dilute aqueous chemistry model successfully reproduced oxalic acid concentrations, when the experiment was performed at cloud-relevant concentrations (glyoxal <300 μM), but predictions deviated from measurements at increasing concentrations. Results elucidate similarities and differences in aqueous glyoxal chemistry in clouds and in wet aerosols. They validate for the first time the accuracy of model predictions at cloud-relevant concentrations. These results suggest that cloud processing of glyoxal could be an important source of SOA. PMID:19924930

Oxidation of alginate and pectate biopolymers by cerium(IV) in perchloric and sulfuric acid solutions: A comparative kinetic and mechanistic study.

PubMed

Fawzy, Ahmed

2016-03-15

The kinetics of oxidation of alginate (Alg) and pectate (Pec) carbohydrate biopolymers was studied by spectrophotometry in aqueous perchloric and sulfuric acid solutions at fixed ionic strengths and temperature. In both acids, the reactions showed a first order dependence on [Ce(IV)], whereas the orders with respect to biopolymer concentrations are less than unity. In perchloric acid, the reactions exhibited less than unit orders with respect to [H(+)] whereas those proceeded in sulfuric acid showed negative fractional-first order dependences on [H(+)]. The effect of ionic strength and dielectric constant was studied. Probable mechanistic schemes for oxidation reactions were proposed. In both acids, the final oxidation products were characterized as mono-keto derivatives of both biopolymers. The activation parameters with respect to the slow step of the mechanisms were computed and discussed. The rate laws were derived and the reaction constants involved in the different steps of the mechanisms were calculated. Copyright © 2015 Elsevier Ltd. All rights reserved.

Solubility of HCL in sulfuric acid at stratospheric temperatures

NASA Technical Reports Server (NTRS)

Williams, Leah R.; Golden, David M.

1993-01-01

The solubility of HCl in sulfuric acid was measured using a Knudsen cell technique. Effective Henry's law constants are reported for sulfuric acid concentrations between 50 and 60 weight percent and for temperatures between 220 and 230 K. The measured values indicate that very little HCl will be dissolved in the stratospheric sulfate aerosol particles.

Toxicity of sulfuric acid mist

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

Treon, J.F.; Dutra, F.R.; Cappel, J.

1950-01-01

Various species were exposed to sulfuric acid mist, 95% less than 2 ..mu..m. Mortality data show susceptibility: guinea pigs > mice > rats > rabbits. Lesions included the following: degeneration of respiratory tract epithelium, hyperemia, edema, focal hemorrhage, patchy atelectasis, and emphysema.

Corrosion study of mild steel in aqueous sulfuric acid solution using 4-methyl-4H-1,2,4-triazole-3-thiol and 2-mercaptonicotinic acid - an experimental and theoretical study

NASA Astrophysics Data System (ADS)

Mehmeti, Valbonë V.; Berisha, Avni R.

2017-08-01

The corrosion behavior of mild steel in 0.1M aqueous sulfuric acid medium has been studied using weight loss, potentiodynamic polarization measurements, quantum chemical calculations and molecular dynamic simulations in the presence and absence of 4-methyl-4H-1,2,4-triazole-3-thiol and 2-mercaptonicotinic acid. Potentiodynamic measurements indicate that these compounds mostly act as mixed inhibitors due to their adsorption on the mild steel surface. The goal of the study was to use theoretical calculations to better understand the inhibition. Monte Carlo simulation was used to calculate the adsorption behavior of the studied molecules onto Fe (1 1 1) and Fe2O3 (1 1 1) surface. The molecules were also studied with the density functional theory (DFT), using the B3LYP functional in order to determine the relationship between the molecular structure and the corrosion inhibition behavior. More accurate adsorption energies between the studied molecules and iron or iron oxide were calculated by using density functional theory with periodic boundary conditions. The calculated theoretical parameters gave important assistance into the understanding the corrosion inhibition mechanism expressed by the molecules and are in full agreement with the experimental results.

Thermodynamics of Aqueous Organic Sulfur Compounds: A Key to the Organic Geochemistry of Hydrothermal Systems?

NASA Technical Reports Server (NTRS)

Schulte, Mitchell; Rogers, Karyn L.; DeVincenzi, Donald L. (Technical Monitor)

2000-01-01

Hydrothermal environments are locations of varied geochemistry due to the disequilibrium between vent fluids and seawater. The disequilibrium geochemistry has been hypothesized to include reactions to synthesize organic compounds. Observations of the organic geochemistry of hydrothermal vent sites has received little attention. Experimental simulations of these environments, however, indicate that organic compounds may have difficulty forming in a purely aqueous environment. On the other hand, thiols. thioesters and disulfides have been implicated as reaction intermediates between CO or CO2 in experiments of carbon reduction in hydrothermal environments as well as in a variety of biological processes and other abiotic reactions (Wachtershauser, 1990, OLEB 20, 173; Heinen and Lauwers, 1996, OLEB 26, 13 1, Huber and Wachtershauser, 1997, Science 276, 245; Russell et al., 1998, in Thermophiles: The keys to molecular evolution and the origin of life?). The reduction of CO2 to thiols, for example, is observed using the FeS-H2S/FeS2 couple to provide the reducing power (see Schoonen et al., 1999, OLEB 29, 5). In addition, the enzyme involved in final stage of methanogenesis, coenzyme-M, is itself a thiol. Thus, organic sulfur compounds may hold the key to the organic chemistry leading to the origin of life at high temperatures. Understanding the biochemical processes of microorganisms that can live to temperatures at least as high as 113 C (Blochl et al., 1996, Extremophiles 1, 14) requires knowledge of the properties of the chemical reactions involved. In order to assess the role of aqueous organic sulfur compounds in hydrothermal organic geochemistry, we have been attempting to determine their thermodynamic properties. We have culled the literature to obtain the properties of organic sulfur compounds. We are able to calculate a number of essential properties, such as free energies of formation, from solubility data available in the literature together with standard

Sulfur amino acid metabolism in doxorubicin-resistant breast cancer cells

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

Ryu, Chang Seon; Kwak, Hui Chan; Lee, Kye Sook

2011-08-15

Although methionine dependency is a phenotypic characteristic of tumor cells, it remains to be determined whether changes in sulfur amino acid metabolism occur in cancer cells resistant to chemotherapeutic medications. We compared expression/activity of sulfur amino acid metabolizing enzymes and cellular levels of sulfur amino acids and their metabolites between normal MCF-7 cells and doxorubicin-resistant MCF-7 (MCF-7/Adr) cells. The S-adenosylmethionine/S-adenosylhomocysteine ratio, an index of transmethylation potential, in MCF-7/Adr cells decreased to {approx} 10% relative to that in MCF-7 cells, which may have resulted from down-regulation of S-adenosylhomocysteine hydrolase. Expression of homocysteine-clearing enzymes, such as cystathionine beta-synthase, methionine synthase/methylene tetrahydrofolate reductase,more » and betaine homocysteine methyltransferase, was up-regulated in MCF-7/Adr cells, suggesting that acquiring doxorubicin resistance attenuated methionine-dependence and activated transsulfuration from methionine to cysteine. Homocysteine was similar, which is associated with a balance between the increased expressions of homocysteine-clearing enzymes and decreased extracellular homocysteine. Despite an elevation in cysteine, cellular GSH decreased in MCF-7/Adr cells, which was attributed to over-efflux of GSH into the medium and down-regulation of the GSH synthesis enzyme. Consequently, MCF-7/Adr cells were more sensitive to the oxidative stress induced by bleomycin and menadione than MCF-7 cells. In conclusion, our results suggest that regulating sulfur amino acid metabolism may be a possible therapeutic target for chemoresistant cancer cells. These results warrant further investigations to determine the role of sulfur amino acid metabolism in acquiring anticancer drug resistance in cancer cells using chemical and biological regulators involved in sulfur amino acid metabolism. - Research Highlights: > MCF-7/Adr cells showed decreases in

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.

An Aqueous Inorganic Polymer Binder for High Performance Lithium–Sulfur Batteries with Flame-Retardant Properties

PubMed Central

2018-01-01

Lithium–sulfur (Li–S) batteries are regarded as promising next-generation high energy density storage devices for both portable electronics and electric vehicles due to their high energy density, low cost, and environmental friendliness. However, there remain some issues yet to be fully addressed with the main challenges stemming from the ionically insulating nature of sulfur and the dissolution of polysulfides in electrolyte with subsequent parasitic reactions leading to low sulfur utilization and poor cycle life. The high flammability of sulfur is another serious safety concern which has hindered its further application. Herein, an aqueous inorganic polymer, ammonium polyphosphate (APP), has been developed as a novel multifunctional binder to address the above issues. The strong binding affinity of the main chain of APP with lithium polysulfides blocks diffusion of polysulfide anions and inhibits their shuttling effect. The coupling of APP with Li ion facilitates ion transfer and promotes the kinetics of the cathode reaction. Moreover, APP can serve as a flame retardant, thus significantly reducing the flammability of the sulfur cathode. In addition, the aqueous characteristic of the binder avoids the use of toxic organic solvents, thus significantly improving safety. As a result, a high rate capacity of 520 mAh g–1 at 4 C and excellent cycling stability of ∼0.038% capacity decay per cycle at 0.5 C for 400 cycles are achieved based on this binder. This work offers a feasible and effective strategy for employing APP as an efficient multifunctional binder toward building next-generation high energy density Li–S batteries. PMID:29532026

Synthesis of the sulfur amino acids: cysteine and methionine.

PubMed

Wirtz, Markus; Droux, Michel

2005-12-01

This review will assess new features reported for the molecular and biochemical aspects of cysteine and methionine biosynthesis in Arabidopsis thaliana with regards to early published data from other taxa including crop plants and bacteria (Escherichia coli as a model). By contrast to bacteria and fungi, plant cells present a complex organization, in which the sulfur network takes place in multiple sites. Particularly, the impact of sulfur amino-acid biosynthesis compartmentalization will be addressed in respect to localization of sulfur reduction. To this end, the review will focus on regulation of sulfate reduction by synthesis of cysteine through the cysteine synthase complex and the synthesis of methionine and its derivatives. Finally, regulatory aspects of sulfur amino-acid biosynthesis will be explored with regards to interlacing processes such as photosynthesis, carbon and nitrogen assimilation.

Synergy effect of naphthenic acid corrosion and sulfur corrosion in crude oil distillation unit

NASA Astrophysics Data System (ADS)

Huang, B. S.; Yin, W. F.; Sang, D. H.; Jiang, Z. Y.

2012-10-01

The synergy effect of naphthenic acid corrosion and sulfur corrosion at high temperature in crude oil distillation unit was studied using Q235 carbon-manganese steel and 316 stainless steel. The corrosion of Q235 and 316 in corrosion media containing sulfur and/or naphthenic acid at 280 °C was investigated by weight loss, scanning electron microscope (SEM), EDS and X-ray diffractometer (XRD) analysis. The results showed that in corrosion media containing only sulfur, the corrosion rate of Q235 and 316 first increased and then decreased with the increase of sulfur content. In corrosion media containing naphthenic acid and sulfur, with the variations of acid value or sulfur content, the synergy effect of naphthenic acid corrosion and sulfur corrosion has a great influence on the corrosion rate of Q235 and 316. It was indicated that the sulfur accelerated naphthenic acid corrosion below a certain sulfur content but prevented naphthenic acid corrosion above that. The corrosion products on two steels after exposure to corrosion media were investigated. The stable Cr5S8 phases detected in the corrosion products film of 316 were considered as the reason why 316 has greater corrosion resistance to that of Q235.

Theoretical estimates of equilibrium sulfur isotope effects in aqueous sulfur systems: Highlighting the role of isomers in the sulfite and sulfoxylate systems

NASA Astrophysics Data System (ADS)

Eldridge, D. L.; Guo, W.; Farquhar, J.

2016-12-01

We present theoretical calculations for all three isotope ratios of sulfur (33S/32S, 34S/32S, 36S/32S) at the B3LYP/6-31+G(d,p) level of theory for aqueous sulfur compounds modeled in 30-40H2O clusters spanning the range of sulfur oxidation state (Sn, n = -2 to +6) for estimating equilibrium fractionation factors in aqueous systems. Computed 34β values based on major isotope (34S/32S) reduced partition function ratios (RPFRs) scale to a first order with sulfur oxidation state and coordination, where 34β generally increase with higher oxidation state and increasing coordination of the sulfur atom. Exponents defining mass dependent relationships based on β values (x/34κ = ln(xβ)/ln(34β), x = 33 or 36) conform to tight ranges over a wide range of temperature for all aqueous compounds (33/34κ ≈ 0.5148-0.5159, 36/34κ ≈ 1.89-1.90 from T ⩾ 0 °C). The exponents converge near a singular value for all compounds at the high temperature limit (33/34κT→∞ = 0.51587 ± 0.00003 and 36/34κT→∞ = 1.8905 ± 0.0002; 1 s.d. of all computed compounds), and typically follow trends based on oxidation state and coordination similar to those seen in 34β values at lower temperatures. Theoretical equilibrium fractionation factors computed from these β-values are compared to experimental constraints for HSO3-T(aq)/SO2(g, aq), SO2(aq)/SO2(g), H2S(aq)/H2S(g), H2S(aq)/HS-(aq), SO42-(aq)/H2ST(aq), S2O32-(aq) (intramolecular), and S2O32-(aq)/H2ST(aq), and generally agree within a reasonable estimation of uncertainties. We make predictions of fractionation factors where other constraints are unavailable. Isotope partitioning of the isomers of protonated compounds in the sulfite and sulfoxylate systems depend strongly on whether protons are bound to either sulfur or oxygen atoms. The magnitude of the HSO3-T/SO32- major isotope (34S/32S) fractionation factor is predicted to increase with temperature from 0 to 70 °C due to the combined effects of the large magnitude (HS)O3

Copper-Sulfate Pentahydrate as a Product of the Waste Sulfuric Acid Solution Treatment

NASA Astrophysics Data System (ADS)

Marković, Radmila; Stevanović, Jasmina; Avramović, Ljiljana; Nedeljković, Dragutin; Jugović, Branimir; Stajić-Trošić, Jasna; Gvozdenović, Milica

2012-12-01

The aim of this study is synthesis of copper-sulfate pentahydrate from the waste sulfuric acid solution-mother liquor generated during the regeneration process of copper bleed solution. Copper is removed from the mother liquor solution in the process of the electrolytic treatment using the insoluble lead anodes alloyed with 6 mass pct of antimony on the industrial-scale equipment. As the result of the decopperization process, copper is removed in the form of the cathode sludge and is precipitated at the bottom of the electrolytic cell. By this procedure, the content of copper could be reduced to the 20 mass pct of the initial value. Chemical characterization of the sludge has shown that it contains about 90 mass pct of copper. During the decopperization process, the very strong poison, arsine, can be formed, and the process is in that case terminated. The copper leaching degree of 82 mass pct is obtained using H2SO4 aqueous solution with the oxygen addition during the cathode sludge chemical treatment at 80 °C ± 5 °C. Obtained copper salt satisfies the requirements of the Serbian Standard for Pesticide, SRPS H.P1. 058. Therefore, the treatment of waste sulfuric acid solutions is of great economic and environmental interest.

The Effects of Sulfuric Acid on Mechanical Properties of Polycrystalline Ice

NASA Astrophysics Data System (ADS)

DeAngelis, M. K.; Lee, M. S.; Huang, K.

2017-12-01

The rates of flow for ice streams and glaciers are an important contributor to models of future sea level rise. Soluble impurities, such as sulfuric acid from acid rain, have been identified in ice cores, making it of utmost importance to understand the complete effects of such impurities on the mechanical properties of ice. While previous studies have provided insight into how sulfuric acid affects the viscosity in glaciers, the effects of sulfuric acid on elastic stiffness and friction has received less attention. In this study, we measured and compared the Young's Modulus and steady-state friction of 10 ppm sulfuric acid doped water ice samples to that of pure water ice samples. Microstructure characterization of the sample indicated that, even at such low concentration, the acid was located in small melt pockets at grain triple junctions. With an ultrasonic velocity testing system at -22 °C, primary waves and secondary waves were sent through each sample and wave velocities were recorded. These values and the density of the samples were used to calculate Young's Modulus. The sulfuric acid doped ice has an elastic stiffness that is less than that of pure ice. Reduced modulus could influence calving rates and other ice shelf processes. Using a custom cryo-biaxial apparatus, the friction of doped ice on rock was directly measured at several programmed velocities. The double direct shear configuration was employed, with a normal stress of 100 kPa and a temperature of -5 °C. Compared to previous studies on pure ice, the sulfuric acid doped ice sample experienced similar steady state friction. However, preliminary results indicate that doped samples exhibited velocity weakening behavior (i.e. as velocity increased, friction decreased) and stick slip events, while pure ice maintained a relatively neutral velocity dependence at this temperature. Field observations have reported stick slip motion at Whillans Ice Stream in Antarctica, but an explanation is unclear

Stabilization of sulfuric acid dimers by ammonia, methylamine, dimethylamine, and trimethylamine

NASA Astrophysics Data System (ADS)

Jen, Coty N.; McMurry, Peter H.; Hanson, David R.

2014-06-01

This study experimentally explores how ammonia (NH3), methylamine (MA), dimethylamine (DMA), and trimethylamine (TMA) affect the chemical formation mechanisms of electrically neutral clusters that contain two sulfuric acid molecules (dimers). Dimers may also contain undetectable compounds, such as water or bases, that evaporate upon ionization and sampling. Measurements were conducted using a glass flow reactor which contained a steady flow of humidified nitrogen with sulfuric acid concentrations of 107 to 109 cm-3. A known molar flow rate of a basic gas was injected into the flow reactor. The University of Minnesota Cluster Chemical Ionization Mass Spectrometer was used to measure the resulting sulfuric acid vapor and cluster concentrations. It was found that, for a given concentration of sulfuric acid vapor, the dimer concentration increases with increasing concentration of the basic gas, eventually reaching a plateau. The base concentrations at which the dimer concentrations saturate suggest NH3 < MA < TMA ≲ DMA in forming stabilized sulfuric acid dimers. Two heuristic models for cluster formation by acid-base reactions are developed to interpret the data. The models provide ranges of evaporation rate constants that are consistent with observations and leads to an analytic expression for nucleation rates that is consistent with atmospheric observations.

Photochemistry of aqueous pyruvic acid

PubMed Central

Griffith, Elizabeth C.; Carpenter, Barry K.; Shoemaker, Richard K.; Vaida, Veronica

2013-01-01

The study of organic chemistry in atmospheric aerosols and cloud formation is of interest in predictions of air quality and climate change. It is now known that aqueous phase chemistry is important in the formation of secondary organic aerosols. Here, the photoreactivity of pyruvic acid (PA; CH3COCOOH) is investigated in aqueous environments characteristic of atmospheric aerosols. PA is currently used as a proxy for α-dicarbonyls in atmospheric models and is abundant in both the gas phase and the aqueous phase (atmospheric aerosols, fog, and clouds) in the atmosphere. The photoreactivity of PA in these phases, however, is very different, thus prompting the need for a mechanistic understanding of its reactivity in different environments. Although the decarboxylation of aqueous phase PA through UV excitation has been studied for many years, its mechanism and products remain controversial. In this work, photolysis of aqueous PA is shown to produce acetoin (CH3CHOHCOCH3), lactic acid (CH3CHOHCOOH), acetic acid (CH3COOH), and oligomers, illustrating the progression from a three-carbon molecule to four-carbon and even six-carbon molecules through direct photolysis. These products are detected using vibrational and electronic spectroscopy, NMR, and MS, and a reaction mechanism is presented accounting for all products detected. The relevance of sunlight-initiated PA chemistry in aqueous environments is then discussed in the context of processes occurring on atmospheric aerosols. PMID:23821751

An Aqueous Inorganic Polymer Binder for High Performance Lithium–Sulfur Batteries with Flame-Retardant Properties

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

Zhou, Guangmin; Liu, Kai; Fan, Yanchen

Lithium–sulfur (Li–S) batteries are regarded as promising next-generation high energy density storage devices for both portable electronics and electric vehicles due to their high energy density, low cost, and environmental friendliness. However, there remain some issues yet to be fully addressed with the main challenges stemming from the ionically insulating nature of sulfur and the dissolution of polysulfides in electrolyte with subsequent parasitic reactions leading to low sulfur utilization and poor cycle life. The high flammability of sulfur is another serious safety concern which has hindered its further application. Herein, an aqueous inorganic polymer, ammonium polyphosphate (APP), has been developedmore » as a novel multifunctional binder to address the above issues. The strong binding affinity of the main chain of APP with lithium polysulfides blocks diffusion of polysulfide anions and inhibits their shuttling effect. The coupling of APP with Li ion facilitates ion transfer and promotes the kinetics of the cathode reaction. Moreover, APP can serve as a flame retardant, thus significantly reducing the flammability of the sulfur cathode. In addition, the aqueous characteristic of the binder avoids the use of toxic organic solvents, thus significantly improving safety. As a result, a high rate capacity of 520 mAh g –1 at 4 C and excellent cycling stability of ~0.038% capacity decay per cycle at 0.5 C for 400 cycles are achieved based on this binder. In conclusion, this work offers a feasible and effective strategy for employing APP as an efficient multifunctional binder toward building next-generation high energy density Li–S batteries.« less

An Aqueous Inorganic Polymer Binder for High Performance Lithium–Sulfur Batteries with Flame-Retardant Properties

DOE PAGES

Zhou, Guangmin; Liu, Kai; Fan, Yanchen; ...

2018-02-14

Lithium–sulfur (Li–S) batteries are regarded as promising next-generation high energy density storage devices for both portable electronics and electric vehicles due to their high energy density, low cost, and environmental friendliness. However, there remain some issues yet to be fully addressed with the main challenges stemming from the ionically insulating nature of sulfur and the dissolution of polysulfides in electrolyte with subsequent parasitic reactions leading to low sulfur utilization and poor cycle life. The high flammability of sulfur is another serious safety concern which has hindered its further application. Herein, an aqueous inorganic polymer, ammonium polyphosphate (APP), has been developedmore » as a novel multifunctional binder to address the above issues. The strong binding affinity of the main chain of APP with lithium polysulfides blocks diffusion of polysulfide anions and inhibits their shuttling effect. The coupling of APP with Li ion facilitates ion transfer and promotes the kinetics of the cathode reaction. Moreover, APP can serve as a flame retardant, thus significantly reducing the flammability of the sulfur cathode. In addition, the aqueous characteristic of the binder avoids the use of toxic organic solvents, thus significantly improving safety. As a result, a high rate capacity of 520 mAh g –1 at 4 C and excellent cycling stability of ~0.038% capacity decay per cycle at 0.5 C for 400 cycles are achieved based on this binder. In conclusion, this work offers a feasible and effective strategy for employing APP as an efficient multifunctional binder toward building next-generation high energy density Li–S batteries.« less

Ion Irradiation of Sulfuric Acid: Implications for its Stability on Europa

NASA Technical Reports Server (NTRS)

Loeffler, M. J.; Hudson, R. L.; Moore, M. H.

2010-01-01

The Galileo near-infrared mapping spectrometer (NIMS) detected regions on Europa's surface containing distorted H2O bands. This distortion likely indicates that there are other molecules mixed with the water ice. Based on spectral comparison, some of the leading possibilities are sulfuric acid, salts. or possibly H3O(+). Previous laboratory studies have shown that sulfuric acid can be created by irradiation of H2OSO2 mixtures, and both molecules are present on Europa. In this project, we were interested in investigating the radiation stability of sulfuric acid (H2SO4) and determining its lifetime on the surface of Europa.

EFFECTS OF ENDOGENOUS AMMONIA ON NEUTRALIZATION OF INHALED SULFURIC ACID AEROSOLS

EPA Science Inventory

Nine male beagle dogs were exposed by inhalation to 0, 6 and 10.5 mg/cu.m sulfuric acid aerosols with normal ammonia, increased blood ammonia, and increased inhaled ammonia to determine whether the addition of ammonia affected the toxicity of sulfuric acid aerosols. Exhaled conce...

Interaction of Atmospheric-Pressure Air Microplasmas with Amino Acids as Fundamental Processes in Aqueous Solution

PubMed Central

Zhou, Renwu; Zhou, Rusen; Zhuang, Jinxing; Zong, Zichao; Zhang, Xianhui; Liu, Dongping; Bazaka, Kateryna; Ostrikov, Kostya

2016-01-01

Plasma medicine is a relatively new field that investigates potential applications of cold atmospheric-pressure plasmas in bioengineering, such as for bacterial inactivation and degradation of organic molecules in water. In order to enunciate mechanisms of bacterial inactivation at molecular or atomic levels, we investigated the interaction of atmospheric-pressure air microplasmas with amino acids in aqueous solution by using high-resolution mass spectrometry (HRMS). Results show that the oxidation effect of plasma-induced species on the side chains of the amino acids can be categorized into four types, namely hydroxylation, nitration, dehydrogenation and dimerization. In addition, relative activities of amino acids resulting from plasma treatment come in descending order as follows: sulfur-containing carbon-chain amino acids > aromatic amino acids > five-membered ring amino acids > basic carbon-chain amino acids. Since amino acids are building blocks of proteins vital to the growth and reproduction of bacteria, these results provide an insight into the mechanism of bacterial inactivation by plasma. PMID:27183129

Sulfur and Sulfuric Acid Microphysics in the Venus Atmosphere: Implications for the Unknown UV Absorber

NASA Astrophysics Data System (ADS)

Gao, P.; Carlson, R. W.; Robinson, T. D.; Crisp, D.; Lyons, J. R.; Yung, Y. L.

2016-12-01

A mystery that has continued to plague our sister planet, Venus, for nearly a century is the nature of the brightness contrasts observed crisscrossing its disk in near-ultraviolet wavelength images. These contrasts - specifically the dark regions - have been attributed to the actions of an unknown UV absorber, knowing the identity of which is integral to understanding the Venus atmosphere due to the high rates of mesospheric heating attributed to the absorption of solar UV. One possible candidate for the UV absorber is polysulfur, which form from polymerization of elemental sulfur arising from SO2 photolysis at the Venus cloud tops under low O2 conditions. In this work we investigate the microphysics of condensed polysulfur and its interaction with the sulfuric acid clouds. We consider the "gumdrop model", where sulfur is allowed to condense onto sulfuric acid cloud particles. We explore the possibility that S2 vapor may condense faster than its loss to gas phase reactions that produce higher allotropes, leading to solid state polymerization to S8. This process may explain the ephemeral and variable nature of the UV absorption.

Case study, comparison of trial burn results from similar sulfuric acid regeneration plants

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

Milaszewski, M.; Johns, T.; Dickerson, W.F.

The primary business of Rhodia Eco Services (Rhodia) is the regeneration of sulfuric acid. Sulfuric acid regeneration requires thermal decomposition of acid to sulfur dioxide, and remaking the acid through chemical reaction. The sulfuric acid regeneration furnace is the ideal place to process pumpable wastes for energy recovery and for thermal destruction. Rhodia is regulated by the Boiler and Industrial Furnace (BIF) regulations (40 CFR 266, Subpart H). The Hammond, Indiana plant is an interim status BIF facility and the Houston, Texas facility is renewing its RCRA incineration permit as a BIF facility. Both plants have conducted BIF Trial Burnsmore » with very similar results. The performance levels demonstrated were at levels better than RCRA/BIF standards for destruction and removal efficiency, metal, HCl/Cl, particulate, dioxin/furan, and organic emissions.« less

Sulfuric Acid Regeneration Waste Disposal Technology.

DTIC Science & Technology

1986-11-01

or poorer correlations of acid load with SAR production. The National Pollutant Discharge Elimination System (NPDES) permit requires one daily 24 hour...systems; and * essentially eliminates [(NH4 )2So4 ] disposal problem. The chief concerns for this process are: " high chemical cost of BaCO 3... biofiltration and fluorination prior to being discharged to a stream which feeds into the Allegheny River. PLANT 6: Sulfuric acid plant in New Jersey

The partitioning of sulfur between multicomponent aqueous fluids and felsic melts

NASA Astrophysics Data System (ADS)

Binder, Bernd; Wenzel, Thomas; Keppler, Hans

2018-02-01

Sulfur partitioning between melt and fluid phase largely controls the environmental impact of volcanic eruptions. Fluid/melt partitioning data also provide the physical basis for interpreting changes in volcanic gas compositions that are used in eruption forecasts. To better constrain some variables that control the behavior of sulfur in felsic systems, in particular the interaction between different volatiles, we studied the partitioning of sulfur between aqueous fluids and haplogranitic melts at 200 MPa and 750-850 °C as a function of oxygen fugacity (Ni-NiO or Re-ReO2 buffer), melt composition (Al/(Na + K) ratio), and fluid composition (NaCl and CO2 content). The data confirm a first-order influence of oxygen fugacity on the partitioning of sulfur. Under "reducing conditions" (Ni-NiO buffer), D fluid/melt is nearly one order of magnitude larger (323 ± 14 for a metaluminous melt) than under "oxidizing conditions" (Re-ReO2 buffer; 74 ± 5 for a metaluminous melt). This effect is likely related to a major change in sulfur speciation in both melt and fluid. Raman spectra of the quenched fluids show the presence of H2S and HS- under reducing conditions and of SO4 2- and HSO4 - under oxidizing conditions, while SO2 is undetectable. The latter observation suggests that already at the Re-ReO2 buffer, sulfur in the fluid is almost completely in the S6+ state and, therefore, more oxidized than expected according to current models. CO2 in the fluid (up to x CO2 = 0.3) has no effect on the fluid/melt partitioning of sulfur, neither under oxidizing nor under reducing conditions. However, the effect of NaCl depends on redox state. While at oxidizing conditions, D fluid/melt is independent of x NaCl, the fluid/melt partition coefficient strongly decreases with NaCl content under reducing conditions, probably due to a change from H2S to NaSH as dominant sulfur species in the fluid. A decrease of D fluid/melt with alkali content in the melt is observed over the entire

Continuous-flow ultrasound assisted oxidative desulfurization (UAOD) process: An efficient diesel treatment by injection of the aqueous phase.

PubMed

Rahimi, Masoud; Shahhosseini, Shahrokh; Movahedirad, Salman

2017-11-01

A new continuous-flow ultrasound assisted oxidative desulfurization (UAOD) process was developed in order to decrease energy and aqueous phase consumption. In this process the aqueous phase is injected below the horn tip leading to enhanced mixing of the phases. Diesel fuel as the oil phase with sulfur content of 1550ppmw and an appropriate mixture of hydrogen peroxide and formic acid as the aqueous phase were used. At the first step, the optimized condition for the sulfur removal has been obtained in the batch mode operation. Hence, the effect of more important oxidation parameters; oxidant-to-sulfur molar ratio, acid-to-sulfur molar ratio and sonication time were investigated. Then the optimized conditions were obtained using Response Surface Methodology (RSM) technique. Afterwards, some experiments corresponding to the best batch condition and also with objective of minimizing the residence time and aqueous phase to fuel volume ratio have been conducted in a newly designed double-compartment reactor with injection of the aqueous phase to evaluate the process in a continuous flow operation. In addition, the effect of nozzle diameter has been examined. Significant improvement on the sulfur removal was observed specially in lower sonication time in the case of dispersion method in comparison with the conventional contact between two phases. Ultimately, the flow pattern induced by ultrasonic device, and also injection of the aqueous phase were analyzed quantitatively and qualitatively by capturing the sequential images. Copyright © 2017 Elsevier B.V. All rights reserved.

Friction and wear of iron in sulfuric acid

NASA Technical Reports Server (NTRS)

Rengstorff, G. W. P.; Miyoshi, K.; Buckley, D. H.

1983-01-01

Elemental iron sliding on aluminum oxide in aerated sulfuric acid concentrations ranging from very dilute (0.000007 N; i.e., 4 ppm) to very concentrated (96 percent acid) was studied. Load and reciprocating sliding speeds were kept constant. With the most dilute acid of 0.7 to 0.0002 N, a complex corrosion product formed that was friable and often increased friction and wear. At concentrations of 0.001 N, metal losses were essentially by wear alone. Because no buildup of corrosion products occurred, this acid concentration became the standard from which to separate metal loss from direct corrosion and mechanical wear losses. When the acid concentration was increased to 5 percent, the high corrosion rate of iron in sulfuric acid strongly dominated the total wear loss. This strong corrosion increased to 30 percent acid, and decreased somewhat at 50 percent in accordance with expectations. However, the low corrosion of iron expected at acid concentrations of 65 to 96 percent was not observed in the wear area. It is apparent that the normal passivating film was being worn away and a galvanic cell established which rapidly attached to the wear area.

46 CFR 153.1046 - Sulfuric acid.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 5 2014-10-01 2014-10-01 false Sulfuric acid. 153.1046 Section 153.1046 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Operations Special Cargo Procedures § 153...

46 CFR 153.1046 - Sulfuric acid.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 5 2013-10-01 2013-10-01 false Sulfuric acid. 153.1046 Section 153.1046 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Operations Special Cargo Procedures § 153...

46 CFR 153.1046 - Sulfuric acid.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 5 2012-10-01 2012-10-01 false Sulfuric acid. 153.1046 Section 153.1046 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Operations Special Cargo Procedures § 153...

Integrated boiler, superheater, and decomposer for sulfuric acid decomposition

DOEpatents

Moore, Robert [Edgewood, NM; Pickard, Paul S [Albuquerque, NM; Parma, Jr., Edward J.; Vernon, Milton E [Albuquerque, NM; Gelbard, Fred [Albuquerque, NM; Lenard, Roger X [Edgewood, NM

2010-01-12

A method and apparatus, constructed of ceramics and other corrosion resistant materials, for decomposing sulfuric acid into sulfur dioxide, oxygen and water using an integrated boiler, superheater, and decomposer unit comprising a bayonet-type, dual-tube, counter-flow heat exchanger with a catalytic insert and a central baffle to increase recuperation efficiency.

Formation rates, stability and reactivity of sulfuric acid - amine clusters predicted by computational chemistry

NASA Astrophysics Data System (ADS)

Kurtén, Theo; Ortega, Ismael; Kupiainen, Oona; Olenius, Tinja; Loukonen, Ville; Reiman, Heidi; McGrath, Matthew; Vehkamäki, Hanna

2013-04-01

Despite the importance of atmospheric particle formation for both climate and air quality, both experiments and non-empirical models using e.g. sulfuric acid, ammonia and water as condensing vapors have so far been unable to reproduce atmospheric observations using realistic trace gas concentrations. Recent experimental and theoretical evidence has shown that this mystery is likely resolved by amines. Combining first-principles evaporation rates for sulfuric acid - dimethylamine clusters with cluster kinetic modeling, we show that even sub-ppt concentrations of amines, together with atmospherically realistic concentrations of sulfuric acid, result in formation rates close to those observed in the atmosphere. Our simulated cluster formation rates are also close to, though somewhat larger than, those measured at the CLOUD experiment in CERN for both sulfuric acid - ammonia and sulfuric acid - dimethylamine systems. A sensitivity analysis indicates that the remaining discrepancy for the sulfuric acid - amine particle formation rates is likely caused by steric hindrances to cluster formation (due to alkyl groups of the amine molecules) rather than by significant errors in the evaporation rates. First-principles molecular dynamic and reaction kinetic modeling shed further light on the microscopic physics and chemistry of sulfuric acid - amine clusters. For example, while the number and type of hydrogen bonds in the clusters typically reach their equilibrium values on a picosecond timescale, and the overall bonding patterns predicted by traditional "static" quantum chemical calculations seem to be stable, the individual atoms participating in the hydrogen bonds continuously change at atmospherically realistic temperatures. From a chemical reactivity perspective, we have also discovered a surprising phenomenon: clustering with sulfuric acid molecules slightly increases the activation energy required for the abstraction of alkyl hydrogens from amine molecules. This implies

What Is the Boiling Point and Heat of Vaporization of Sulfuric Acid?

ERIC Educational Resources Information Center

Myers, R. Thomas

1983-01-01

Discusses the values presented in various handbooks for the boiling point and heat of vaporization of sulfuric acid, noting discrepencies. Analyzes various approaches to data presentation, discussing the data on sulfuric acid in light of the Trouton constant. Points out the need for a more critical use of tables. (JM)

Aqueous-phase source of formic acid in clouds

NASA Technical Reports Server (NTRS)

Chameides, W. L.; Davis, D. D.

1983-01-01

The coupled gas- and aqueous-phase cloud chemistry of HCOOH were examined for controlling factors in the acidity of cloud and rainwater. Attention was given to the aqueous OH/HO2 system that yields an OH species that is highly reactive with other species, notably SO2 and the formaldehyde/formic acid complex. A numerical model was developed to simulate the cloud chemistry in the remote troposphere, with considerations given to CH4-CO-NO(x)-O3-H(x)O(y) system. It was determined that aqueous phase OH radicals can produce and destroy formic acid droplets in daylight conditions, as well as control formic acid levels in rainwater. It is sugested that the same types of reactions may be involved in the control of acetic acid and other organic acids.

Reduction in environmental impact of sulfuric acid hydrolysis of bamboo for production of fuel ethanol.

PubMed

Sun, Zhao-Yong; Tang, Yue-Qin; Morimura, Shigeru; Kida, Kenji

2013-01-01

Fuel ethanol can be produced from bamboo by concentrated sulfuric acid hydrolysis followed by continuous ethanol fermentation. To reduce the environmental impact of this process, treatment of the stillage, reuse of the sulfuric acid and reduction of the process water used were studied. The total organic carbon (TOC) concentration of stillage decreased from 29,688 to 269 mg/l by thermophilic methane fermentation followed by aerobic treatment. Washing the solid residue from acid hydrolysis with effluent from the biological treatment increased the sugar recovery from 69.3% to 79.3%. Sulfuric acid recovered during the acid-sugar separation process was condensed and reused for hydrolysis, resulting in a sugar recovery efficiency of 76.8%, compared to 80.1% when fresh sulfuric acid was used. After acetate removal, the condensate could be reused as elution water in the acid-sugar separation process. As much as 86.3% of the process water and 77.6% of the sulfuric acid could be recycled. Copyright © 2012 Elsevier Ltd. All rights reserved.

Vanadium Extraction from Shale via Sulfuric Acid Baking and Leaching

NASA Astrophysics Data System (ADS)

Shi, Qihua; Zhang, Yimin; Liu, Tao; Huang, Jing

2018-01-01

Fluorides are widely used to improve vanadium extraction from shale in China. Sulfuric acid baking-leaching (SABL) was investigated as a means of recovering vanadium which does not require the use of fluorides and avoids the productions of harmful fluoride-containing wastewater. Various effective factors were systematically studied and the experimental results showed that 90.1% vanadium could be leached from the shale. On the basis of phase transformations and structural changes after baking the shale, a mechanism of vanadium extraction from shale via SABL was proposed. The mechanism can be described as: (1) sulfuric acid diffusion into particles; (2) the formation of concentrated sulfuric acid media in the particles after water evaporation; (3) hydroxyl groups in the muscovite were removed and transient state [SO4 2-] was generated; and (4) the metals in the muscovite were sulfated by active [SO4 2-] and the vanadium was released. Thermodynamics modeling confirmed this mechanism.

Backscatter laser depolarization studies of simulated stratospheric aerosols - Crystallized sulfuric acid droplets

NASA Technical Reports Server (NTRS)

Sassen, Kenneth; Zhao, Hongjie; Yu, Bing-Kun

1989-01-01

The optical depolarizing properties of simulated stratospheric aerosols were studied in laboratory laser (0.633 micrometer) backscattering experiments for application to polarization lidar observations. Clouds composed of sulfuric acid solution droplets, some treated with ammonia gas, were observed during evaporation. The results indicate that the formation of minute ammonium sulfate particles from the evaporation of acid droplets produces linear depolarization ratios of beta equivalent to 0.02, but beta equivalent to 0.10 to 0.15 are generated from aged acid cloud aerosols and acid droplet crystalization effects following the introduction of ammonia gas into the chamber. It is concluded that partially crystallized sulfuric acid droplets are a likely candidate for explaining the lidar beta equivalent to 0.10 values that have been observed in the lower stratosphere in the absence of the relatively strong backscattering from homogeneous sulfuric acid droplet (beta equivalent to 0) or ice crystal (beta equivalent to 0.5) clouds.

Backscatter laser depolarization studies of simulated stratospheric aerosols: Crystallized sulfuric acid droplets

NASA Technical Reports Server (NTRS)

Sassen, Kenneth; Zhao, Hongjie; Yu, Bing-Kun

1988-01-01

The optical depolarizing properties of simulated stratospheric aerosols were studied in laboratory laser (0.633 micrometer) backscattering experiments for application to polarization lidar observations. Clouds composed of sulfuric acid solution droplets, some treated with ammonia gas, were observed during evaporation. The results indicate that the formation of minute ammonium sulfate particles from the evaporation of acid droplets produces linear depolarization ratios of beta equivalent to 0.02, but beta equivalent to 0.10 to 0.15 are generated from aged acid cloud aerosols and acid droplet crystallization effects following the introduction of ammonia gas into the chamber. It is concluded that partially crystallized sulfuric acid droplets are a likely candidate for explaining the lidar beta equivalent to 0.10 values that have been observed in the lower stratosphere in the absence of the relatively strong backscattering from homogeneous sulfuric acid droplet (beta equivalent to 0) or ice crystal (beta equivalent to 0.5) clouds.

Aqueous infrared carboxylate absorbances: Aliphatic di-acids

USGS Publications Warehouse

Cabaniss, S.E.; Leenheer, J.A.; McVey, I.F.

1998-01-01

Aqueous attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectra of 18 aliphatic di-carboxylic acids are reported as a function of pH. The spectra show isosbestic points and intensity changes which indicate that Beer's law is obeyed, and peak frequencies lie within previously reported ranges for aqueous carboxylates and pure carboxylic acids. Intensity sharing from the symmetric carboxylate stretch is evident in many cases, so that bands which are nominally due to alkyl groups show increased intensity at higher pH. The asymmetric stretch of the HA- species is linearly related to the microscopic acidity constant of the H2A species, with ??pK 2 intervening atoms). The results suggest that aqueous ATR-FTIR may be able to estimate 'intrinsic' pKa values of carboxylic acids, in addition to providing quantitative estimates of ionization. ?? 1998 Elsevier Science B.V. All rights reserved.

Impact of Sulfuric Acid Treatment of Halloysite on Physico-Chemic Property Modification

PubMed Central

Gaaz, Tayser Sumer; Sulong, Abu Bakar; Kadhum, Abdul Amir H.; Nassir, Mohamed H.; Al-Amiery, Ahmed A.

2016-01-01

Halloysite (HNT) is treated with sulfuric acid and the physico-chemical properties of its morphology, surface activity, physical and chemical properties have been investigated when HNT is exposed to sulfuric acid with treatment periods of 1 h (H1), 3 h (H3), 8 h (H8), and 21 h (H21). The significance of this and similar work lies in the importance of using HNT as a functional material in nanocomposites. The chemical structure was characterized by Fourier transform infrared spectroscopy (FTIR). The spectrum demonstrates that the hydroxyl groups were active for grafting modification using sulfuric acid, promoting a promising potential use for halloysite in ceramic applications as filler for novel clay-polymer nanocomposites. From the X-ray diffraction (XRD) spectrum, it can be seen that the sulfuric acid breaks down the HNT crystal structure and alters it into amorphous silica. In addition, the FESEM images reveal that the sulfuric acid treatment dissolves the AlO6 octahedral layers and induces the disintegration of SiO4 tetrahedral layers, resulting in porous nanorods. The Bruncher-Emmett-Teller (BET) surface area and total pore volume of HNTs showed an increase. The reaction of the acid with both the outer and inner surfaces of the nanotubes causes the AlO6 octahedral layers to dissolve, which leads to the breakdown and collapse of the tetrahedral layers of SiO4. The multi-fold results presented in this paper serve as a guide for further HNT functional treatment for producing new and advanced nanocomposites. PMID:28773741

Impact of Sulfuric Acid Treatment of Halloysite on Physico-Chemic Property Modification.

PubMed

Gaaz, Tayser Sumer; Sulong, Abu Bakar; Kadhum, Abdul Amir H; Nassir, Mohamed H; Al-Amiery, Ahmed A

2016-07-26

Halloysite (HNT) is treated with sulfuric acid and the physico-chemical properties of its morphology, surface activity, physical and chemical properties have been investigated when HNT is exposed to sulfuric acid with treatment periods of 1 h (H1), 3 h (H3), 8 h (H8), and 21 h (H21). The significance of this and similar work lies in the importance of using HNT as a functional material in nanocomposites. The chemical structure was characterized by Fourier transform infrared spectroscopy (FTIR). The spectrum demonstrates that the hydroxyl groups were active for grafting modification using sulfuric acid, promoting a promising potential use for halloysite in ceramic applications as filler for novel clay-polymer nanocomposites. From the X-ray diffraction (XRD) spectrum, it can be seen that the sulfuric acid breaks down the HNT crystal structure and alters it into amorphous silica. In addition, the FESEM images reveal that the sulfuric acid treatment dissolves the AlO₆ octahedral layers and induces the disintegration of SiO₄ tetrahedral layers, resulting in porous nanorods. The Bruncher-Emmett-Teller (BET) surface area and total pore volume of HNTs showed an increase. The reaction of the acid with both the outer and inner surfaces of the nanotubes causes the AlO₆ octahedral layers to dissolve, which leads to the breakdown and collapse of the tetrahedral layers of SiO₄. The multi-fold results presented in this paper serve as a guide for further HNT functional treatment for producing new and advanced nanocomposites.

Resolving the shape of a sonoluminescence pulse in sulfuric acid by the use of streak camera.

PubMed

Huang, Wei; Chen, Weizhong; Cui, Weicheng

2009-06-01

A streak camera is used to measure the shape of sonoluminescence pulses from a cavitation bubble levitated stably in a sulfuric acid solution. The shape and response to an acoustic pressure field of the sonoluminescence pulse in 85% by weight sulfuric acid are qualitatively similar to those in water. However, the pulse width in sulfuric acid is wider than that in water by over one order of magnitude. The width of the sonoluminescence pulse is strongly dependent on the concentration of the sulfuric acid solution, while the skewed distribution of the shape remains unchanged.

Aqueous-Phase Acetic Acid Ketonization over Monoclinic Zirconia

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

Cai, Qiuxia; Lopez-Ruiz, Juan A.; Cooper, Alan R.

The effect of aqueous phase on the acetic acid ketonization over monoclinic zirconia has been investigated using first-principles based density functional theory (DFT) calculations. To capture the aqueous phase chemistry over the solid zirconia catalyst surface, the aqueous phase is represented by 111 explicit water molecules with a liquid water density of 0.93 g/cm3 and the monoclinic zirconia is modeled by the most stable surface structure . The dynamic nature of aqueous phase/ interface was studied using ab initio molecular dynamics simulation, indicating that nearly half of the surface Zr sites are occupied by either adsorbed water molecules or hydroxylmore » groups at 550 K. DFT calculations show that the adsorption process of acetic acid from the liquid water phase to the surface is nearly thermodynamically neutral with a Gibbs free energy of -2.3 kJ/mol although the adsorption strength of acetic acid on the surface in aqueous phase is much stronger than in vapor phase. Therefore it is expected that the adsorption of acetic acid will dramatically affects aqueous phase ketonization reactivity over the monoclinic zirconia catalyst. Using the same ketonization mechanism via the β-keto acid intermediate, we have compared acetic acid ketonization to acetone in both vapor and aqueous phases. Our DFT calculation results show although the rate-determining step of the β-keto acid formation via the C-C coupling is not pronouncedly affected, the presence of liquid water molecules will dramatically affect dehydrogenation and hydrogenation steps via proton transfer mechanism. This work was financially supported by the United States Department of Energy (DOE)’s Bioenergy Technologies Office (BETO) and performed at the Pacific Northwest National Laboratory (PNNL). PNNL is a multi-program national laboratory operated for DOE by Battelle Memorial Institute. Computing time and advanced catalyst characterization use was granted by a user proposal at the William R. Wiley

A rotamer energy level study of sulfuric acid.

PubMed

Partanen, Lauri; Pesonen, Janne; Sjöholm, Elina; Halonen, Lauri

2013-10-14

It is a common approach in quantum chemical calculations for polyatomic molecules to rigidly constrain some of the degrees of freedom in order to make the calculations computationally feasible. However, the presence of the rigid constraints also affects the kinetic energy operator resulting in the frozen mode correction, originally derived by Pesonen [J. Chem. Phys. 139, 144310 (2013)]. In this study, we compare the effects of this correction to several different approximations to the kinetic energy operator used in the literature, in the specific case of the rotamer energy levels of sulfuric acid. The two stable conformers of sulfuric acid are connected by the rotations of the O-S-O-H dihedral angles and possess C2 and Cs symmetry in the order of increasing energy. Our results show that of the models tested, the largest differences with the frozen mode corrected values were obtained by simply omitting the passive degrees of freedom. For the lowest 17 excited states, this inappropriate treatment introduces an increase of 9.6 cm(-1) on average, with an increase of 8.7 cm(-1) in the zero-point energies. With our two-dimensional potential energy surface calculated at the CCSD(T)-F12a/VDZ-F12 level, we observe a radical shift in the density of states compared to the harmonic picture, combined with an increase in zero point energy. Thus, we conclude that the quantum mechanical inclusion of the different conformers of sulfuric acid have a significant effect on its vibrational partition function, suggesting that it will also have an impact on the computational values of the thermodynamic properties of any reactions where sulfuric acid plays a role. Finally, we also considered the effect of the anharmonicities for the other vibrational degrees of freedom with a VSCF-calculation at the DF-MP2-F12/VTZ-F12 level of theory but found that the inclusion of the other conformer had the more important effect on the vibrational partition function.

Excited triplet state of N-(9-methylpurin-6-yl)pyridinium cation as an efficient photosensitizer in the oxidation of sulfur-containing amino acids. Laser flash and steady-state photolysis studies

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

Marciniak, B.; Hug, G.L.; Bobrowski, K.

1995-01-11

In this paper, we present and discuss the results of a detailed mechanistic study of the photosensitized oxidation of sulfur-containing amino acids by N-(9-methylpurin-6-yl)pyridinium cations in aqueous solution. The results provide data on the photoreactivity of the pyridinium salts (derived from the purine bases) in the presence of the electron donors such as sulfur-containing organic compounds and give new experimental evidence for the general mechanism of the sensitized photooxidation of thioethers proposed previously. 39 refs., 6 figs., 2 tabs.

Unexpectedly acidic nanoparticles formed in dimethylamine-ammonia-sulfuric-acid nucleation experiments at CLOUD

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

Lawler, Michael J.; Winkler, Paul M.; Kim, Jaeseok

New particle formation driven by acid–base chemistry was initiated in the CLOUD chamber at CERN by introducing atmospherically relevant levels of gas-phase sulfuric acid and dimethylamine (DMA). Ammonia was also present in the chamber as a gas-phase contaminant from earlier experiments. The composition of particles with volume median diameters (VMDs) as small as 10 nm was measured by the Thermal Desorption Chemical Ionization Mass Spectrometer (TDCIMS). Particulate ammonium-to-dimethylaminium ratios were higher than the gas-phase ammonia-to-DMA ratios, suggesting preferential uptake of ammonia over DMA for the collected 10–30 nm VMD particles. This behavior is not consistent with present nanoparticle physicochemical models,more » which predict a higher dimethylaminium fraction when NH 3 and DMA are present at similar gas-phase concentrations. Despite the presence in the gas phase of at least 100 times higher base concentrations than sulfuric acid, the recently formed particles always had measured base : acid ratios lower than 1 : 1. The lowest base fractions were found in particles below 15 nm VMD, with a strong size-dependent composition gradient. The reasons for the very acidic composition remain uncertain, but a plausible explanation is that the particles did not reach thermodynamic equilibrium with respect to the bases due to rapid heterogeneous conversion of SO 2 to sulfate. Furthermore, these results indicate that sulfuric acid does not require stabilization by ammonium or dimethylaminium as acid–base pairs in particles as small as 10 nm.« less

Unexpectedly acidic nanoparticles formed in dimethylamine-ammonia-sulfuric-acid nucleation experiments at CLOUD

DOE PAGES

Lawler, Michael J.; Winkler, Paul M.; Kim, Jaeseok; ...

2016-11-03

New particle formation driven by acid–base chemistry was initiated in the CLOUD chamber at CERN by introducing atmospherically relevant levels of gas-phase sulfuric acid and dimethylamine (DMA). Ammonia was also present in the chamber as a gas-phase contaminant from earlier experiments. The composition of particles with volume median diameters (VMDs) as small as 10 nm was measured by the Thermal Desorption Chemical Ionization Mass Spectrometer (TDCIMS). Particulate ammonium-to-dimethylaminium ratios were higher than the gas-phase ammonia-to-DMA ratios, suggesting preferential uptake of ammonia over DMA for the collected 10–30 nm VMD particles. This behavior is not consistent with present nanoparticle physicochemical models,more » which predict a higher dimethylaminium fraction when NH 3 and DMA are present at similar gas-phase concentrations. Despite the presence in the gas phase of at least 100 times higher base concentrations than sulfuric acid, the recently formed particles always had measured base : acid ratios lower than 1 : 1. The lowest base fractions were found in particles below 15 nm VMD, with a strong size-dependent composition gradient. The reasons for the very acidic composition remain uncertain, but a plausible explanation is that the particles did not reach thermodynamic equilibrium with respect to the bases due to rapid heterogeneous conversion of SO 2 to sulfate. Furthermore, these results indicate that sulfuric acid does not require stabilization by ammonium or dimethylaminium as acid–base pairs in particles as small as 10 nm.« less

Lipoic Acid as a Possible Pharmacological Source of Hydrogen Sulfide/Sulfane Sulfur.

PubMed

Bilska-Wilkosz, Anna; Iciek, Małgorzata; Kowalczyk-Pachel, Danuta; Górny, Magdalena; Sokołowska-Jeżewicz, Maria; Włodek, Lidia

2017-03-02

The aim of the present study was to verify whether lipoic acid (LA) itself is a source of H₂S and sulfane sulfur. It was investigated in vitro non-enzymatically and enzymatically (in the presence of rat tissue homogenate). The results indicate that both H₂S and sulfane sulfur are formed from LA non-enzymatically in the presence of environmental light. These results suggest that H₂S is the first product of non-enzymatic light-dependent decomposition of LA that is, probably, next oxidized to sulfane sulfur-containing compound(s). The study performed in the presence of rat liver and kidney homogenate revealed an increase of H₂S level in samples containing LA and its reduced form dihydrolipoic acid (DHLA). It was accompanied by a decrease in sulfane sulfur level. It seems that, in these conditions, DHLA acts as a reducing agent that releases H₂S from an endogenous pool of sulfane sulfur compounds present in tissues. Simultaneously, it means that exogenous LA cannot be a direct donor of H₂S/sulfane sulfur in animal tissues. The present study is an initial approach to the question whether LA itself is a donor of H₂S/sulfane sulfur.

POTENTIAL ABATEMENT PRODUCTION AND MARKETING OF BYPRODUCT SULFURIC ACID IN THE U.S

EPA Science Inventory

The report gives results of an evaluation of the market potential for sulfur and sulfuric acid byproducts of combustion in power plant boilers. (Air quality regulations require control of SOx emissions from power plant boilers. Recovery of sulfur in useful form would avoid waste ...

Formaldehyde instrument development and boundary layer sulfuric acid: Implications for photochemistry

NASA Astrophysics Data System (ADS)

Case Hanks, Anne Theresa

This work presents the development of a laser-induced fluorescence technique to measure atmospheric formaldehyde. In conjunction with the technique, the design of a compact, narrow linewidth, etalon-tuned titanium: sapphire laser cavity which is pumped by the second harmonic of a kilohertz Nd:YAG laser is also presented. The fundamental tunable range is from 690-1100 nm depending on mirror reflectivities and optics kit used. The conversion efficiency is at least 25% for the fundamental, and 2-3% for intracavity frequency doubling from 3.5-4W 532 nm pump power. The linewidth is <0.1 cm-1, and the pulsewidth is 18 nsec. Applications of this cavity include the measurement of trace gas species by laser-induced fluorescence, cavity ringdown spectroscopy, and micropulse lidar in the UV-visible region. Also presented are observations of gas-phase sulfuric acid from the NEAQS-ITCT 2K4 (New England Air Quality Study--- Intercontinental Transport and Chemical Transformation) field campaign in July and August 2004. Sulfuric acid values are reported for a polluted environment and possible nucleation events as well as particle growth within the boundary layer are explored. Sulfate production rates via gas phase oxidation of sulfur dioxide are also reported. This analysis allows an important test of our ability to predict sulfuric acid concentration and probe its use as a fast time response photochemical tracer for the hydroxyl radical, OH. In comparison, the NASA time-dependent photochemical box model is used to calculate OH concentration. Nighttime H2SO4 values are examined to test our understanding of nocturnal OH levels and oxidation processes. In comparison, sulfuric acid from a large ground based mission in Tecamac, Mexico (near the northern boundary of Mexico City) during MIRAGE-Mex field campaign (March 2006) is presented. This and other measurements are used to characterize atmospheric oxidation and predict sulfuric acid and OH concentrations at the site. The

Thermal Regeneration of Sulfuric Acid Hydrates after Irradiation

NASA Technical Reports Server (NTRS)

Loeffler, Mark J.; Hudson, Reggie L.

2012-01-01

In an attempt to more completely understand the surface chemistry of the jovian icy satellites, we have investigated the effect of heating on two irradiated crystalline sulfuric acid hydrates, H2SO4 4H2O and H2SO4 H2O. At temperatures relevant to Europa and the warmer jovian satellites, post-irradiation heating recrystallized the amorphized samples and increased the intensities of the remaining hydrate's infrared absorptions. This thermal regeneration of the original hydrates was nearly 100% efficient, indicating that over geological times, thermally-induced phase transitions enhanced by temperature fluctuations will reform a large fraction of crystalline hydrated sulfuric acid that is destroyed by radiation processing. The work described is the first demonstration of the competition between radiation-induced amorphization and thermally-induced recrystallization in icy ionic solids relevant to the outer Solar System.

New particle formation from sulfuric acid and amines: Comparison of monomethylamine, dimethylamine, and trimethylamine

NASA Astrophysics Data System (ADS)

Olenius, Tinja; Halonen, Roope; Kurtén, Theo; Henschel, Henning; Kupiainen-Määttä, Oona; Ortega, Ismael K.; Jen, Coty N.; Vehkamäki, Hanna; Riipinen, Ilona

2017-07-01

Amines are bases that originate from both anthropogenic and natural sources, and they are recognized as candidates to participate in atmospheric aerosol particle formation together with sulfuric acid. Monomethylamine, dimethylamine, and trimethylamine (MMA, DMA, and TMA, respectively) have been shown to enhance sulfuric acid-driven particle formation more efficiently than ammonia, but both theory and laboratory experiments suggest that there are differences in their enhancing potentials. However, as quantitative concentrations and thermochemical properties of different amines remain relatively uncertain, and also for computational reasons, the compounds have been treated as a single surrogate amine species in large-scale modeling studies. In this work, the differences and similarities of MMA, DMA, and TMA are studied by simulations of molecular cluster formation from sulfuric acid, water, and each of the three amines. Quantum chemistry-based cluster evaporation rate constants are applied in a cluster population dynamics model to yield cluster concentrations and formation rates at boundary layer conditions. While there are differences, for instance, in the clustering mechanisms and cluster hygroscopicity for the three amines, DMA and TMA can be approximated as a lumped species. Formation of nanometer-sized particles and its dependence on ambient conditions is roughly similar for these two: both efficiently form clusters with sulfuric acid, and cluster formation is rather insensitive to changes in temperature and relative humidity. Particle formation from sulfuric acid and MMA is weaker and significantly more sensitive to ambient conditions. Therefore, merging MMA together with DMA and TMA introduces inaccuracies in sulfuric acid-amine particle formation schemes.

Corrosion Study of Mild Steel in Aqueous Sulfuric Acid Solution Using 4-Methyl-4H-1,2,4-Triazole-3-Thiol and 2-Mercaptonicotinic Acid—An Experimental and Theoretical Study

PubMed Central

Mehmeti, Valbonë V.; Berisha, Avni R.

2017-01-01

The corrosion behavior of mild steel in 0.1 M aqueous sulfuric acid medium has been studied using weight loss, potentiodynamic polarization measurements, quantum chemical calculations, and molecular dynamic simulations in the presence and absence of 4-methyl-4H-1,2,4-triazole-3-thiol and 2-mercaptonicotinic acid. Potentiodynamic measurements indicate that these compounds mostly act as mixed inhibitors due to their adsorption on the mild steel surface. The goal of the study was to use theoretical calculations to better understand the inhibition. Monte Carlo simulation was used to calculate the adsorption behavior of the studied molecules onto Fe (1 1 1) and Fe2O3 (1 1 1) surface. The molecules were also studied with the density functional theory (DFT), using the B3LYP functional in order to determine the relationship between the molecular structure and the corrosion inhibition behavior. More accurate adsorption energies between the studied molecules and iron or iron oxide were calculated by using DFT with periodic boundary conditions. The calculated theoretical parameters gave important assistance into the understanding the corrosion inhibition mechanism expressed by the molecules and are in full agreement with the experimental results. PMID:28971092

CHARACTERIZATION OF SULFUR CONTAINING ANALOGS OF MONOMETHYLARSONIC ACID IN AQUEOUS PHASE STANDARDS AND CARROT EXTRACTS BY IC-ICP-MS AND IC-ESI-MS/MS

EPA Science Inventory

Recently, sulfur analogs of well known arsenicals have been identified, generating a need for stable species-specific standards. This presentation will focus on the identification and characterization of a novel species, monomethylthioarsonic acid (MMTA), in carrots. A standard...

A Demonstration of Acid Rain

ERIC Educational Resources Information Center

Fong, Man Wai

2004-01-01

A demonstration showing acid rain formation is described. Oxides of sulfur and nitrogen that result from the burning of fossil fuels are the major pollutants of acid rain. In this demonstration, SO[subscript 2] gas is produced by the burning of matches. An acid-base indicator will show that the dissolved gas turns an aqueous solution acidic.

46 CFR 151.50-21 - Sulfuric acid.

Code of Federal Regulations, 2014 CFR

2014-10-01

...° Baumé) or greater concentrations with or without an inhibitor, provided the corrosive effect on steel... corrosive effect on steel measured at 100 °F is not greater than that of 52° Baumé commercial sulfuric acid, may be transported in unlined pressure vessel type cargo tanks independent of the vessel's structure...

46 CFR 151.50-21 - Sulfuric acid.

Code of Federal Regulations, 2011 CFR

2011-10-01

...° Baumé) or greater concentrations with or without an inhibitor, provided the corrosive effect on steel... corrosive effect on steel measured at 100 °F is not greater than that of 52° Baumé commercial sulfuric acid, may be transported in unlined pressure vessel type cargo tanks independent of the vessel's structure...

46 CFR 151.50-21 - Sulfuric acid.

Code of Federal Regulations, 2012 CFR

2012-10-01

...° Baumé) or greater concentrations with or without an inhibitor, provided the corrosive effect on steel... corrosive effect on steel measured at 100 °F is not greater than that of 52° Baumé commercial sulfuric acid, may be transported in unlined pressure vessel type cargo tanks independent of the vessel's structure...

46 CFR 151.50-21 - Sulfuric acid.

Code of Federal Regulations, 2010 CFR

2010-10-01

...° Baumé) or greater concentrations with or without an inhibitor, provided the corrosive effect on steel... corrosive effect on steel measured at 100 °F is not greater than that of 52° Baumé commercial sulfuric acid, may be transported in unlined pressure vessel type cargo tanks independent of the vessel's structure...

46 CFR 151.50-21 - Sulfuric acid.

Code of Federal Regulations, 2013 CFR

2013-10-01

...° Baumé) or greater concentrations with or without an inhibitor, provided the corrosive effect on steel... corrosive effect on steel measured at 100 °F is not greater than that of 52° Baumé commercial sulfuric acid, may be transported in unlined pressure vessel type cargo tanks independent of the vessel's structure...

Theoretical estimation of equilibrium sulfur isotope fractionations among aqueous sulfite species: Implications for isotope models of microbial sulfate reduction

NASA Astrophysics Data System (ADS)

Eldridge, D. L.; Farquhar, J.; Guo, W.

2015-12-01

Sulfite (sensu lato), an intermediate in a variety sulfur redox processes, plays a particularly important role in microbial sulfate reduction. It exists intracellularly as multiple species between sets of enzymatic reactions that transform sulfate to sulfide, with the exact speciation depending on pH, T, and ionic strength. However, the complex speciation of sulfite is ignored in current isotope partitioning models of microbial sulfate reduction and simplified solely to the pyramidal SO32- (sulfite sensu stricto), due to a lack of appropriate constraints. We theoretically estimated the equilibrium sulfur isotope fractionations (33S/32S, 34S/32S, 36S/32S) among all documented sulfite species in aqueous solution, including sulfite (SO32-), bisulfite isomers and dimers ((HS)O3-, (HO)SO2-, S2O52-), and SO2(aq), through first principles quantum mechanical calculations. The calculations were performed at B3LYP/6-31+G(d,p) level using cluster models with 30-40 water molecules surrounding the solute. Our calculated equilibrium fractionation factors compare well to the available experimental constraints and suggest that the minor and often-ignored tetrahedral (HS)O3- isomer of bisulfite strongly influences isotope partitioning behavior in the sulfite system under most environmentally relevant conditions, particularly fractionation magnitudes and unusual temperature dependence. For example, we predict that sulfur isotope fractionation between sulfite and bulk bisulfite in solution should have an apparent inverse temperature dependence due to the influence of (HS)O3- and its increased stability at higher temperatures. Our findings highlight the need to appropriately account for speciation/isomerization of sulfur species in sulfur isotope studies. We will also present similar calculation results of other aqueous sulfur compounds (e.g., H2S/HS-, SO42-, S2O32-, S3O62-, and poorly documented SO22- species), and discuss the implication of our results for microbial sulfate

Charles H. Winston and Confederate Sulfuric Acid.

ERIC Educational Resources Information Center

Riethmiller, Steven

1995-01-01

Describes the invention and use of a sulfuric acid chamber by Charles Henry Winston during the Civil War. This invention helped supply munitions for the South. Winston, who was President of the Richmond Female Institute in Virginia, constructed the chamber at his farm and was granted a patent by the Confederate Patent Office in 1863. (PVD)

Bacteria and Acidic Drainage from Coal Refuse: Inhibition by Sodium Lauryl Sulfate and Sodium Benzoate

PubMed Central

Dugan, Patrick R.; Apel, William A.

1983-01-01

The application of an aqueous solution of sodium lauryl sulfate and sodium benzoate to the surface of high-sulfur coal refuse resulted in the inhibition of iron-and sulfur-oxidizing chemoautotrophic bacteria and in the decrease of acidic drainage from the refuse, suggesting that acid drainage can be abated in the field by inhibiting iron- and sulfur-oxidizing bacteria. PMID:16346347

Method for removing elemental sulfur in sour gas wells

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

Sample, T.E. Jr.

1975-09-30

A process is described for removing sulfur deposits from sour gas wells. The formation, well, and surface equipment are contacted with a chemical composition whose aqueous solution will solubilize the sulfur by primary chemical reaction and contains a wetting agent to facilitate and accelerate the sulfur dissolution and removal. The wetting agent or surfactant may be any of a wide variety of surface-active substances such as soaps, sodium or ammonium salts of alkyl or alkyl-aryl sulfates and sulfonates. Nonionic surfactants are preferred, such as ethoxylated substituted phenols. The aqueous solvents are capable of chemically reacting with sulfur to form water-solublemore » sulfur derivatives and include aqueous solutions of alkalies, bases (both inorganic and organic), ammonia, sulfites, bisulfites, etc. (6 claims)« less

Acid-Catalyzed Isomerization of Carvone to Carvacrol

ERIC Educational Resources Information Center

Kjonaas, Richard A.; Mattingly, Shawn P.

2005-01-01

The acid-catalyzed isomerization of carvone to carvacrol, first reported by Ritter and Ginsburg, is especially well suited with a permanent-magnet FT instrument. The acid-catalyzed isomerization of carvone to carvacrol produced a 61% yield after a three hour reflux with 30% aqueous sulfuric acid.

Study on mechanisms of different sulfuric acid leaching technologies of chromite

NASA Astrophysics Data System (ADS)

Shi, Pei-yang; Liu, Cheng-jun; Zhao, Qing; Shi, Hao-nan

2017-09-01

The extraction of chromate from chromite via the sulfuric acid leaching process has strong potential for practical use because it is a simple and environmentally friendly process. This paper aims to study the sulfuric acid leaching process using chromite as a raw material via either microwave irradiation or in the presence of an oxidizing agent. The results show that the main phases in Pakistan chromite are ferrichromspinel, chrompicotite, hortonolite, and silicate embedded around the spinel phases. Compared with the process with an oxidizing agent, the process involving microwaves has a higher leaching efficiency. When the mass fraction of sulfuric acid was 80% and the leaching time was 20 min, the efficiency could exceed 85%. In addition, the mechanisms of these two technologies fundamentally differ. When the leaching was processed in the presence of an oxidizing agent, the silicate was leached first and then expanded. By contrast, in the case of leaching under microwave irradiation, the chromite was dissolved layer by layer and numerous cracks appeared at the particle surface because of thermal shock. In addition, the silicate phase shrunk instead of expanding.

Assessment of nanofiltration and reverse osmosis potentialities to recover metals, sulfuric acid, and recycled water from acid gold mining effluent.

PubMed

Ricci, Bárbara C; Ferreira, Carolina D; Marques, Larissa S; Martins, Sofia S; Amaral, Míriam C S

This work assessed the potential of nanofiltration (NF) and reverse osmosis (RO) to treat acid streams contaminated with metals, such as effluent from the pressure oxidation process (POX) used in refractory gold ore processing. NF and RO were evaluated in terms of rejections of sulfuric acid and metals. Regarding NF, high sulfuric acid permeation (∼100%), was observed, while metals were retained with high efficiencies (∼90%), whereas RO led to high acid rejections (<88%) when conducted in pH values higher than 1. Thus, sequential use of NF and RO was proved to be a promising treatment for sulfuric acid solutions contaminated by metals, such as POX effluent. In this context, a purified acid stream could be recovered in NF permeate, which could be further concentrated in RO. Recovered acid stream could be reused in the gold ore processing or commercialized. A metal-enriched stream could be also recovered in NF retentate and transferred to a subsequent metal recovery stage. In addition, considering the high acid rejection obtained through the proposed system, RO permeate could be used as recycling water.

Investigation of acyl migration in mono- and dicaffeoylquinic acids under aqueous basic, aqueous acidic, and dry roasting conditions.

PubMed

Deshpande, Sagar; Jaiswal, Rakesh; Matei, Marius Febi; Kuhnert, Nikolai

2014-09-17

Acyl migration in chlorogenic acids describes the process of migration of cinnamoyl moieties from one quinic acid alcohol group to another, thus interconverting chlorogenic acid regioisomers. It therefore constitutes a special case of transesterification reaction. Acyl migration constitutes an important reaction pathway in both coffee roasting and brewing, altering the structure of chlorogenic acid initially present in the green coffee bean. In this contribution we describe detailed and comprehensive mechanistic studies comparing inter- and intramolecular acyl migration involving the seven most common chlorogenic acids in coffee. We employe aqueous acidic and basic conditions mimicking the brewing of coffee along with dry roasting conditions. We show that under aqueous basic conditions intramolecular acyl migration is fully reversible with basic hydrolysis competing with acyl migration. 3-Caffeoylquinic acid was shown to be most labile to basic hydrolysis. We additionally show that the acyl migration process is strongly pH dependent with increased transesterification taking place at basic pH. Under dry roasting conditions acyl migration competes with dehydration to form lactones. We argue that acyl migration precedes lactonization, with 3-caffeoylquinic acid lactone being the predominant product.

Dental erosion in workers exposed to sulfuric acid in lead storage battery manufacturing facility.

PubMed

Suyama, Yuji; Takaku, Satoru; Okawa, Yoshikazu; Matsukubo, Takashi

2010-01-01

Dental erosion, and specifically its symptoms, has long been studied in Japan as an occupational dental disease. However, in recent years, few studies have investigated the development of this disease or labor hygiene management aimed at its prevention. As a result, interest in dental erosion is comparatively low, even among dental professionals. Our investigation at a lead storage battery factory in 1991 found that the work environmental sulfuric acid density was above the tolerable range (1.0mg/m(3)) and that longterm workers had dental erosion. Therefore, workers handling sulfuric acid were given an oral examination and rates of dental erosion by tooth type, rates of erosion by number of working years and rates of erosion by sulfuric acid density in the work environment investigated. Where dental erosion was diagnosed, degree of erosion was identified according to a diagnostic criterion. No development of dental erosion was detected in the maxillary teeth, and erosion was concentrated in the anterior mandibular teeth. Its prevalence was as high as 20%. Rates of dental erosion rose precipitously after 10 working years. The percentages of workers with dental erosion were 42.9% for 10-14 years, 57.1% for 15-19 years and 66.7% for over 20 years with 22.5% for total number of workers. The percentages of workers with dental erosion rose in proportion to work environmental sulfuric acid density: 17.9% at 0.5-1.0, 25.0% at 1.0-4.0 and 50.0% at 4.0-8.0mg/m(3). This suggests that it is necessary to evaluate not only years of exposure to sulfuric acid but also sulfuric acid density in the air in factory workers.

Heat-Exchange Fluids for Sulfuric Acid Vaporizers

NASA Technical Reports Server (NTRS)

Lawson, D. D.; Petersen, G. R.

1982-01-01

Some fluorine-substituted organic materials meet criteria for heat-exchange fluids in contact with sulfuric acid. Most promising of these are perfluoropropylene oxide polymers with degree of polymerization (DP) between 10 and 50. It is desirable to have DP in high range because vapor pressure of material decreases as DP increases, and high-DP liquids have lower loss due to vaporization.

Tetrathionate and Elemental Sulfur Shape the Isotope Composition of Sulfate in Acid Mine Drainage

PubMed Central

Balci, Nurgul; Brunner, Benjamin; Turchyn, Alexandra V.

2017-01-01

Sulfur compounds in intermediate valence states, for example elemental sulfur, thiosulfate, and tetrathionate, are important players in the biogeochemical sulfur cycle. However, key understanding about the pathways of oxidation involving mixed-valance state sulfur species is still missing. Here we report the sulfur and oxygen isotope fractionation effects during the oxidation of tetrathionate (S4O62−) and elemental sulfur (S°) to sulfate in bacterial cultures in acidic conditions. Oxidation of tetrathionate by Acidithiobacillus thiooxidans produced thiosulfate, elemental sulfur and sulfate. Up to 34% of the tetrathionate consumed by the bacteria could not be accounted for in sulfate or other intermediate-valence state sulfur species over the experiments. The oxidation of tetrathionate yielded sulfate that was initially enriched in 34S (ε34SSO4−S4O6) by +7.9‰, followed by a decrease to +1.4‰ over the experiment duration, with an average ε34SSO4−S4O6 of +3.5 ± 0.2‰ after a month of incubation. We attribute this significant sulfur isotope fractionation to enzymatic disproportionation reactions occurring during tetrathionate decomposition, and to the incomplete transformation of tetrathionate into sulfate. The oxygen isotope composition of sulfate (δ18OSO4) from the tetrathionate oxidation experiments indicate that 62% of the oxygen in the formed sulfate was derived from water. The remaining 38% of the oxygen was either inherited from the supplied tetrathionate, or supplied from dissolved atmospheric oxygen (O2). During the oxidation of elemental sulfur, the product sulfate became depleted in 34S between −1.8 and 0‰ relative to the elemental sulfur with an average for ε34SSO4−S0 of −0.9 ± 0.2‰ and all the oxygen atoms in the sulfate derived from water with an average normal oxygen isotope fractionation (ε18OSO4−H2O) of −4.4‰. The differences observed in δ18OSO4 and the sulfur isotope composition of sulfate (δ34SSO4), acid

RECOVERY OF ACTINIDES FROM AQUEOUS NITRIC ACID SOLUTIONS

DOEpatents

Ader, M.

1963-11-19

A process of recovering actinides is presented. Tetravalent actinides are extracted from rare earths in an aqueous nitric acid solution with a ketone and back-extracted from the ketone into an aqueous medium. The aqueous actinide solution thus obtained, prior to concentration by boiling, is sparged with steam to reduce its ketone to a maximum content of 3 grams per liter. (AEC)

On the transformation of sulfur-containing amino acids and peptides to volatile sulfur compounds (VSC) in the human mouth.

PubMed

Wåler, S M

1997-10-01

Halitosis is most often caused by oral conditions. Volatile sulfur compounds (VSC), constituting the major components of oral malodor, are produced by anaerobic, gram-negative bacteria retained mainly in periodontal pockets or on the tongue dorsum. Sulfur-containing amino acids serve as substrate for these bacteria. VSC have also been found to have unfavorable effect on the tissue. The aim of this study was to examine whether normal, healthy individuals with no history of halitosis were able to produce VSC from cysteine, when applied as a mouthrinse. A further aim of the study was to investigate and compare the potential of other sulfur-containing amino acids and peptides as substrates for oral VSC production and to localize the odor-production sites. A portable sulfide monitor was used for VSC registration. Results showed that all test subjects produced high oral concentrations of VSC upon rinses with cysteine, which thus seems to be a major substrate for VSC production. The other sulfur-containing substrates had much less effect. It was found that the tongue was the major site for VSC production, and that saliva per se caused low VSC production.

Sugar Dehydration without Sulfuric Acid: No More Choking Fumes in the Classroom!

NASA Astrophysics Data System (ADS)

Silverstein, Todd P.; Zhang, Yi

1998-06-01

Sugar is a common reagent often used in colorful classroom demonstrations. It produces a growing column of black ash when dehydrated by concentrated sulfuric acid, and it produces a brilliant purple flame when combusted with potassium chlorate. Unfortunately, both of these reactions also produce copious quantities of noxious fumes which make them problematic as lecture demonstrations. We have modified and combined these two reactions. Our demonstration uses no sulfuric acid, yields relatively little smoke, and produces an exciting and unpredictable growing column of black carbon.

New Parameterizations for Neutral and Ion-Induced Sulfuric Acid-Water Particle Formation in Nucleation and Kinetic Regimes

NASA Astrophysics Data System (ADS)

Määttänen, Anni; Merikanto, Joonas; Henschel, Henning; Duplissy, Jonathan; Makkonen, Risto; Ortega, Ismael K.; Vehkamäki, Hanna

2018-01-01

We have developed new parameterizations of electrically neutral homogeneous and ion-induced sulfuric acid-water particle formation for large ranges of environmental conditions, based on an improved model that has been validated against a particle formation rate data set produced by Cosmics Leaving OUtdoor Droplets (CLOUD) experiments at European Organization for Nuclear Research (CERN). The model uses a thermodynamically consistent version of the Classical Nucleation Theory normalized using quantum chemical data. Unlike the earlier parameterizations for H2SO4-H2O nucleation, the model is applicable to extreme dry conditions where the one-component sulfuric acid limit is approached. Parameterizations are presented for the critical cluster sulfuric acid mole fraction, the critical cluster radius, the total number of molecules in the critical cluster, and the particle formation rate. If the critical cluster contains only one sulfuric acid molecule, a simple formula for kinetic particle formation can be used: this threshold has also been parameterized. The parameterization for electrically neutral particle formation is valid for the following ranges: temperatures 165-400 K, sulfuric acid concentrations 104-1013 cm-3, and relative humidities 0.001-100%. The ion-induced particle formation parameterization is valid for temperatures 195-400 K, sulfuric acid concentrations 104-1016 cm-3, and relative humidities 10-5-100%. The new parameterizations are thus applicable for the full range of conditions in the Earth's atmosphere relevant for binary sulfuric acid-water particle formation, including both tropospheric and stratospheric conditions. They are also suitable for describing particle formation in the atmosphere of Venus.

Interaction of sulfuric acid corrosion and mechanical wear of iron

NASA Technical Reports Server (NTRS)

Rengstorff, G. W. P.; Miyoshi, K.; Buckley, D. H.

1986-01-01

Friction and wear experiment were conducted with elemental iron sliding on aluminum oxide in aerated sulfuric acid at concentrations ranging from very dilute (0.00007 N; i.e., 4 ppm) to very concentrated (96 percent acid). Load and reciprocating sliding speed were kept constant. With the most dilute acid concentration of 0.00007 to 0.0002 N, a complex corrosion product formed that was friable and often increased friction and wear. At slightly higher concentrations of 0.001 N, metal losses were essentially by wear alone. Because no buildup of corrosion products occurred, this acid concentration became the standard from which to separate metal loss from direct corrosion and mechanical wear losses. When the acid concentration was increased to 5 percent (1 N), the well-established high corrosion rate of iron in sulfuric acid strongly dominated the total wear loss. This strong corrosion increased to 30 percent acid and decreased somewhat to 50 percent acid in accordance with expectations. However, the low corrosion of iron expected at acid concentrations of 65 to 96 percent was not observed in the wear area. It was apparent that the normal passivating film was being worn away and a galvanic cell established that rapidly attacked the wear area. Under the conditions where direct corrosion losses were highest, the coefficient of friction was the lowest.

Interaction of sulfuric acid corrosion and mechanical wear of iron

NASA Technical Reports Server (NTRS)

Rengstorff, G. W. P.; Miyoshi, K.; Buckley, D. H.

1984-01-01

Friction and wear experiments were conducted with elemental iron sliding on aluminum oxide in aerated sulfuric acid at concentrations ranging from very dilute (0.00007 N; i.e., 4 ppm) to very concentrated (96 percent acid). Load and reciprocating sliding speed were kept constant. With the most dilute acid concentration of 0.00007 to 0.0002 N, a complex corrosion product formed that was friable and often increased friction and wear. At slightly higher concentrations of 0.001 N, metal losses were essentially by wear alone. Because no buildup of corrosion products occurred, this acid concentration became the standard from which to separate metal loss from direct corrosion and mechanical wear losses. When the acid concentration was increased to 5 percent (1 N), the well-established high corrosion rate of iron in sulfuric acid strongly dominated the total wear loss. This strong corrosion increased to 30 percent acid and decreased somewhat to 50 percent acid in accordance with expectations. However, the low corrosion of iron expected at acid concentrations of 65 to 96 percent was not observed in the wear area. It was apparent that the normal passivating film was being worn away and a galvanic cell established that rapidly attacked the wear area. Under the conditions where direct corrosion losses were highest, the coefficient of friction was the lowest.

Extraction of uranium from tailings by sulfuric acid leaching with oxidants

NASA Astrophysics Data System (ADS)

Huang, Jing; Li, Mi; Zhang, Xiaowen; Huang, Chunmei; Wu, Xiaoyan

2017-06-01

Recovery of uranium have been performed by leaching uranium-containing tailings in sulfuric acid system with the assistance of HF, HClO4, H2O2 and MnO2. The effect of reagent dosage, sulfuric acid concentration, Liquid/solid ratio, reaction temperature and particle size on the leaching of uranium were investigated. The results show that addiction of HF, HClO4, H2O2 and MnO2 significantly increased the extraction of uranium under 1M sulphuric acid condition and under the optimum reaction conditions a dissolution fraction of 85% by HClO4, 90% by HF, 95% by H2O2 can be reached respectively. The variation of technological mineralogy properites of tailings during leaching process show that the assistants can break gangue effectively. These observations suggest that optimum oxidants could potentially influence the extraction of uranium from tailings even under dilute acid condition.

Raman spectra of amino acids and their aqueous solutions

NASA Astrophysics Data System (ADS)

Zhu, Guangyong; Zhu, Xian; Fan, Qi; Wan, Xueliang

2011-03-01

Amino acids are the basic "building blocks" that combine to form proteins and play an important physiological role in all life-forms. Amino acids can be used as models for the examination of the importance of intermolecular bonding in life processes. Raman spectra serve to obtain information regarding molecular conformation, giving valuable insights into the topology of more complex molecules (peptides and proteins). In this paper, amino acids and their aqueous solution have been studied by Raman spectroscopy. Comparisons of certain values for these frequencies in amino acids and their aqueous solutions are given. Spectra of solids when compared to those of the solute in solution are invariably much more complex and almost always sharper. We present a collection of Raman spectra of 18 kinds of amino acids ( L-alanine, L-arginine, L-aspartic acid, cystine, L-glutamic acid, L-glycine, L-histidine, L-isoluecine, L-leucine, L-lysine, L-phenylalanine, L-methionone, L-proline, L-serine, L-threonine, L-tryptophan, L-tyrosine, L-valine) and their aqueous solutions that can serve as references for the interpretation of Raman spectra of proteins and biological materials.

Potential heat exchange fluids for use in sulfuric acid vaporizers

NASA Technical Reports Server (NTRS)

Lawson, D. D.; Petersen, G. R.

1979-01-01

A series of perhalocarbons are proposed as candidate heat exchange fluids for service in thermochemical cycles for hydrogen production that involve direct contact of the fluid with sulfuric acid and vaporization of the acid. The required chemical and physical criteria of the liquids are described and the results of some preliminary high temperature test data are presented.

Raman spectroscopic study of the conformation of dicarboxylic acid salts in aqueous solutions

NASA Astrophysics Data System (ADS)

Fukushima, Kunio; Watanabe, Toshiaki; Umemura, Matome

1986-08-01

It is already known that the molecules of long chain monocarboxylic acid salts have a tendency to form micelles in aqueous solutions, the molecular chain taking the all- trans zigzag structure. However it is considered difficult for dicarboxylic acid salts to adopt the same structure as the monocarboxylic acid salts as they have two carboxyl groups, one on each end of the molecular chain. Therefore, a special structure is expected to exist for dicarboxylic acid salts in aqueous solution. In order to examine this, Raman spectra of suberic acid salt and azelaic acid salt in aqueous solution were measured and the normal vibrational calculation carried out, showing that dicarboxylic acid salts have a helical structure in aqueous solution.

Complex chemical composition of colored surface films formed from reactions of propanal in sulfuric acid at upper troposphere/lower stratosphere aerosol acidities.

PubMed

Van Wyngarden, A L; Pérez-Montaño, S; Bui, J V H; Li, E S W; Nelson, T E; Ha, K T; Leong, L; Iraci, L T

Particles in the upper troposphere and lower stratosphere (UT/LS) consist mostly of concentrated sulfuric acid (40-80 wt %) in water. However, airborne measurements have shown that these particles also contain a significant fraction of organic compounds of unknown chemical composition. Acid-catalyzed reactions of carbonyl species are believed to be responsible for significant transfer of gas phase organic species into tropospheric aerosols and are potentially more important at the high acidities characteristic of UT/LS particles. In this study, experiments combining sulfuric acid (H 2 SO 4 ) with propanal and with mixtures of propanal with glyoxal and/or methylglyoxal at acidities typical of UT/LS aerosols produced highly colored surface films (and solutions) that may have implications for aerosol properties. In order to identify the chemical processes responsible for the formation of the surface films, attenuated total reflectance-Fourier transform infrared (ATR-FTIR) and 1 H nuclear magnetic resonance (NMR) spectroscopies were used to analyze the chemical composition of the films. Films formed from propanal were a complex mixture of aldol condensation products, acetals and propanal itself. The major aldol condensation products were the dimer (2-methyl-2-pentenal) and 1,3,5-trimethylbenzene that was formed by cyclization of the linear aldol condensation trimer. Additionally, the strong visible absorption of the films indicates that higher-order aldol condensation products must also be present as minor species. The major acetal species were 2,4,6-triethyl-1,3,5-trioxane and longer-chain linear polyacetals which are likely to separate from the aqueous phase. Films formed on mixtures of propanal with glyoxal and/or methylglyoxal also showed evidence of products of cross-reactions. Since cross-reactions would be more likely than self-reactions under atmospheric conditions, similar reactions of aldehydes like propanal with common aerosol organic species like glyoxal

Complex chemical composition of colored surface films formed from reactions of propanal in sulfuric acid at upper troposphere/lower stratosphere aerosol acidities

PubMed Central

Van Wyngarden, A. L.; Pérez-Montaño, S.; Bui, J. V. H.; Li, E. S. W.; Nelson, T. E.; Ha, K. T.; Leong, L.; Iraci, L. T.

2016-01-01

Particles in the upper troposphere and lower stratosphere (UT/LS) consist mostly of concentrated sulfuric acid (40–80 wt %) in water. However, airborne measurements have shown that these particles also contain a significant fraction of organic compounds of unknown chemical composition. Acid-catalyzed reactions of carbonyl species are believed to be responsible for significant transfer of gas phase organic species into tropospheric aerosols and are potentially more important at the high acidities characteristic of UT/LS particles. In this study, experiments combining sulfuric acid (H2SO4) with propanal and with mixtures of propanal with glyoxal and/or methylglyoxal at acidities typical of UT/LS aerosols produced highly colored surface films (and solutions) that may have implications for aerosol properties. In order to identify the chemical processes responsible for the formation of the surface films, attenuated total reflectance–Fourier transform infrared (ATR-FTIR) and 1H nuclear magnetic resonance (NMR) spectroscopies were used to analyze the chemical composition of the films. Films formed from propanal were a complex mixture of aldol condensation products, acetals and propanal itself. The major aldol condensation products were the dimer (2-methyl-2-pentenal) and 1,3,5-trimethylbenzene that was formed by cyclization of the linear aldol condensation trimer. Additionally, the strong visible absorption of the films indicates that higher-order aldol condensation products must also be present as minor species. The major acetal species were 2,4,6-triethyl-1,3,5-trioxane and longer-chain linear polyacetals which are likely to separate from the aqueous phase. Films formed on mixtures of propanal with glyoxal and/or methylglyoxal also showed evidence of products of cross-reactions. Since cross-reactions would be more likely than self-reactions under atmospheric conditions, similar reactions of aldehydes like propanal with common aerosol organic species like glyoxal and

Sulfur Nanoparticles Synthesis and Characterization from H2S Gas, Using Novel Biodegradable Iron Chelates in W/O Microemulsion

NASA Astrophysics Data System (ADS)

Deshpande, Aniruddha S.; Khomane, Ramdas B.; Vaidya, Bhalchandra K.; Joshi, Renuka M.; Harle, Arti S.; Kulkarni, Bhaskar D.

2008-06-01

Sulfur nanoparticles were synthesized from hazardous H2S gas using novel biodegradable iron chelates in w/o microemulsion system. Fe3+ malic acid chelate (0.05 M aqueous solution) was studied in w/o microemulsion containing cyclohexane, Triton X-100 and n-hexanol as oil phase, surfactant, co-surfactant, respectively, for catalytic oxidation of H2S gas at ambient conditions of temperature, pressure, and neutral pH. The structural features of sulfur nanoparticles have been characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), energy dispersive spectroscopy (EDS), diffused reflectance infra-red Fourier transform technique, and BET surface area measurements. XRD analysis indicates the presence of α-sulfur. TEM analysis shows that the morphology of sulfur nanoparticles synthesized in w/o microemulsion system is nearly uniform in size (average particle size 10 nm) and narrow particle size distribution (in range of 5 15 nm) as compared to that in aqueous surfactant systems. The EDS analysis indicated high purity of sulfur (>99%). Moreover, sulfur nanoparticles synthesized in w/o microemulsion system exhibit higher antimicrobial activity (against bacteria, yeast, and fungi) than that of colloidal sulfur.

Sulfur Nanoparticles Synthesis and Characterization from H2S Gas, Using Novel Biodegradable Iron Chelates in W/O Microemulsion

PubMed Central

2008-01-01

Sulfur nanoparticles were synthesized from hazardous H2S gas using novel biodegradable iron chelates in w/o microemulsion system. Fe3+–malic acid chelate (0.05 M aqueous solution) was studied in w/o microemulsion containing cyclohexane, Triton X-100 andn-hexanol as oil phase, surfactant, co-surfactant, respectively, for catalytic oxidation of H2S gas at ambient conditions of temperature, pressure, and neutral pH. The structural features of sulfur nanoparticles have been characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), energy dispersive spectroscopy (EDS), diffused reflectance infra-red Fourier transform technique, and BET surface area measurements. XRD analysis indicates the presence of α-sulfur. TEM analysis shows that the morphology of sulfur nanoparticles synthesized in w/o microemulsion system is nearly uniform in size (average particle size 10 nm) and narrow particle size distribution (in range of 5–15 nm) as compared to that in aqueous surfactant systems. The EDS analysis indicated high purity of sulfur (>99%). Moreover, sulfur nanoparticles synthesized in w/o microemulsion system exhibit higher antimicrobial activity (against bacteria, yeast, and fungi) than that of colloidal sulfur.

Limits to sulfur accumulation in transgenic lupin seeds expressing a foreign sulfur-rich protein.

PubMed

Tabe, Linda M; Droux, Michel

2002-03-01

The low sulfur amino acid content of legume seeds restricts their nutritive value for animals. We have investigated the limitations to the accumulation of sulfur amino acids in the storage proteins of narrow leaf lupin (Lupinus angustifolius) seeds. Variation in sulfur supply to lupin plants affected the sulfur amino acid accumulation in the mature seed. However, when sulfur was in abundant supply, it accumulated to a large extent in oxidized form, rather than reduced form, in the seeds. At all but severely limiting sulfur supply, addition of a transgenic (Tg) sink for organic sulfur resulted in an increase in seed sulfur amino acid content. We hypothesize that demand, or sink strength for organic sulfur, which is itself responsive to environmental sulfur supply, was the first limit to the methionine (Met) and cysteine (Cys) content of wild-type lupin seed protein under most growing conditions. In Tg, soil-grown seeds expressing a foreign Met- and Cys-rich protein, decreased pools of free Met, free Cys, and glutathione indicated that the rate of synthesis of sulfur amino acids in the cotyledon had become limiting. Homeostatic mechanisms similar to those mediating the responses of plants to environmental sulfur stress resulted in an adjustment of endogenous protein composition in Tg seeds, even when grown at adequate sulfur supply. Uptake of sulfur by lupin cotyledons, as indicated by total seed sulfur at maturity, responded positively to increased sulfur supply, but not to increased demand in the Tg seeds.

Limits to Sulfur Accumulation in Transgenic Lupin Seeds Expressing a Foreign Sulfur-Rich Protein

PubMed Central

Tabe, Linda M.; Droux, Michel

2002-01-01

The low sulfur amino acid content of legume seeds restricts their nutritive value for animals. We have investigated the limitations to the accumulation of sulfur amino acids in the storage proteins of narrow leaf lupin (Lupinus angustifolius) seeds. Variation in sulfur supply to lupin plants affected the sulfur amino acid accumulation in the mature seed. However, when sulfur was in abundant supply, it accumulated to a large extent in oxidized form, rather than reduced form, in the seeds. At all but severely limiting sulfur supply, addition of a transgenic (Tg) sink for organic sulfur resulted in an increase in seed sulfur amino acid content. We hypothesize that demand, or sink strength for organic sulfur, which is itself responsive to environmental sulfur supply, was the first limit to the methionine (Met) and cysteine (Cys) content of wild-type lupin seed protein under most growing conditions. In Tg, soil-grown seeds expressing a foreign Met- and Cys-rich protein, decreased pools of free Met, free Cys, and glutathione indicated that the rate of synthesis of sulfur amino acids in the cotyledon had become limiting. Homeostatic mechanisms similar to those mediating the responses of plants to environmental sulfur stress resulted in an adjustment of endogenous protein composition in Tg seeds, even when grown at adequate sulfur supply. Uptake of sulfur by lupin cotyledons, as indicated by total seed sulfur at maturity, responded positively to increased sulfur supply, but not to increased demand in the Tg seeds. PMID:11891268

Theoretical study of interactions between cysteine and perfluoropropanoic acid in gas and aqueous phase

NASA Astrophysics Data System (ADS)

Holmes, Tiffani M.; Doskocz, Jacek; Wright, Terrance; Hill, Glake A.

The interaction of perfluoropropanoic acid (PFPA) with the amino acid cysteine was investigated using density functional theory. Previous studies suggest that the peroxisome proliferator chemical, perfluorooctanoic acid, is circulated throughout the body by way of sulfur-containing amino acids. We present conformational analysis of the interactions of PFPA, a small model of perfluorooctanoic acid, with the sulfur-containing amino acid which occur by the process of hydrogen bonding, in which the hydrogen of the sulfhydryl group interacts with the carboxyl oxygen, and the amino nitrogen forms a hydrogen bond with the hydrogen of the bond OH group of the fluorinated alkyl. We also show in our structures a recently characterized weak nonbonded interaction between divalent sulfur and a main chain carboxyl oxygen in proteins. B3LYP calculated free energies and interaction energies predict low-energy, high-interaction conformations for complex systems of perfluorinated fatty acid interactions with cysteine.

Aqueous Alteration on Mars. Chapter 23

NASA Technical Reports Server (NTRS)

Ming, Douglas W.; Morris, Richard V.; Clark, Benton C.

2007-01-01

Aqueous alteration is the change in composition of a rock, produced in response to interactions with H2O-bearing ices, liquids, and vapors by chemical weathering. A variety of mineralogical and geochemical indicators for aqueous alteration on Mars have been identified by a combination of surface and orbital robotic missions, telescopic observations, characterization of Martian meteorites, and laboratory and terrestrial analog studies. Mineralogical indicators for aqueous alteration include goethite (lander), jarosite (lander), kieserite (orbiter), gypsum (orbiter) and other Fe-, Mg-, and Ca-sulfates (landers), halides (meteorites, lander), phyllosilicates (orbiter, meteorites), hematite and nanophase iron oxides (telescopic, orbiter, lander), and Fe-, Mg-, and Ca-carbonates (meteorites). Geochemical indicators (landers only) for aqueous alteration include Mg-, Ca-, and Fe-sulfates, halides, and secondary aluminosilicates such as smectite. Based upon these indicators, several styles of aqueous alteration have been suggested on Mars. Acid-sulfate weathering (e.g., formation of jarosite, gypsum, hematite, and goethite), may occur during (1) the oxidative weathering of ultramafic igneous rocks containing sulfides, (2) sulfuric acid weathering of basaltic materials, and (3) acid fog (i.e., vapors rich in H2SO4) weathering of basaltic or basaltic-derived materials. Near-neutral or alkaline alteration occurs when solutions with pH near or above 7 move through basaltic materials and form phases such as phyllosilicates and carbonates. Very low water:rock ratios appear to have been prominent at most of the sites visited by landed missions because there is very little alteration (leaching) of the original basaltic composition (i.e., the alteration is isochemical or in a closed hydrologic system). Most of the aqueous alteration appears to have occurred early in the history of the planet (3 to 4.5 billion years ago); however, minor aqueous alteration may be occurring at the

Method of removing oxides of sulfur and oxides of nitrogen from exhaust gases

DOEpatents

Walker, Richard J.

1986-01-01

A continuous method is presented for removing both oxides of sulfur and oxides of nitrogen from combustion or exhaust gases with the regeneration of the absorbent. Exhaust gas is cleaned of particulates and HCl by a water scrub prior to contact with a liquid absorbent that includes an aqueous solution of bisulfite and sulfite ions along with a metal chelate, such as, an iron or zinc aminopolycarboxylic acid. Following contact with the combustion gases the spent absorbent is subjected to electrodialysis to transfer bisulfite ions into a sulfuric acid solution while splitting water with hydroxide and hydrogen ion migration to equalize electrical charge. The electrodialysis stack includes alternate layers of anion selective and bipolar membranes. Oxides of nitrogen are removed from the liquid absorbent by air stripping at an elevated temperature and the regenerated liquid absorbent is returned to contact with exhaust gases for removal of sulfur oxides and nitrogen oxides.

Partitioning of mercury in aqueous biphasic systems and on ABEC resins.

PubMed

Rogers, R D; Griffin, S T

1998-06-26

Poly(ethylene glycol)-based aqueous biphasic systems (PEG-ABS) can be utilized to separate and recover metal ions in environmental and hydrometallurgical applications. A concurrent study was conducted comparing the partitioning of mercury between aqueous layers in an ABS [Me-PEG-5000/(NH4)2SO4] and partitioning of mercury from aqueous solutions to aqueous biphasic extraction chromatographic (ABEC-5000) resins. In ammonium sulfate solutions, mercury partitions to the salt-rich phase in ABS, but by using halide ion extractants, mercury will partition to the PEG-rich phase after formation of a chloro, bromo or iodo complex. The efficacy of the extractant increases in the order Cl- sulfuric acid. The addition of sulfuric acid to (NH4)2SO4 solution results in ABEC retention of mercury even in the absence of halide extractant.

Thermometric titration of some monoprotic and diprotic acids in aqueous and non-aqueous media.

PubMed

Harries, R J

1968-12-01

Some mono- and diprotic acids have been titrated thermometrically with strong alkalis in aqueous and non-aqueous media. Thermograms with sharp arrest points were obtained, from which heats of neutralization were measured. Heats of neutralization in the media used were compared and an effect attributable to hydrogen bonding was found.

Seed storage protein deficiency improves sulfur amino acid content in common bean (Phaseolus vulgaris L.): redirection of sulfur from gamma-glutamyl-S-methyl-cysteine.

PubMed

Taylor, Meghan; Chapman, Ralph; Beyaert, Ronald; Hernández-Sebastià, Cinta; Marsolais, Frédéric

2008-07-23

The contents of sulfur amino acids in seeds of common bean ( Phaseolus vulgaris L.) are suboptimal for nutrition. They accumulate large amounts of a gamma-glutamyl dipeptide of S-methyl-cysteine, a nonprotein amino acid that cannot substitute for methionine or cysteine in the diet. Protein accumulation and amino acid composition were characterized in three genetically related lines integrating a progressive deficiency in major seed storage proteins, phaseolin, phytohemagglutinin, and arcelin. Nitrogen, carbon, and sulfur contents were comparable among the three lines. The contents of S-methyl-cysteine and gamma-glutamyl-S-methyl-cysteine were progressively reduced in the mutants. Sulfur was shifted predominantly to the protein cysteine pool, while total methionine was only slightly elevated. Methionine and cystine contents (mg per g protein) were increased by up to ca. 40%, to levels slightly above FAO guidelines on amino acid requirements for human nutrition. These findings may be useful to improve the nutritional quality of common bean.

Separation of aliphatic carboxylic acids and benzenecarboxylic acids by ion-exclusion chromatography with various cation-exchange resin columns and sulfuric acid as eluent.

PubMed

Ohta, Kazutoku; Ohashi, Masayoshi; Jin, Ji-Ye; Takeuchi, Toyohide; Fujimoto, Chuzo; Choi, Seong-Ho; Ryoo, Jae-Jeong; Lee, Kwang-Pill

2003-05-16

The application of various hydrophilic cation-exchange resins for high-performance liquid chromatography (sulfonated silica gel: TSKgel SP-2SW, carboxylated silica gel: TSKgel CM-2SW, sulfonated polymethacrylate resin: TSKgel SP-5PW, carboxylated polymethacrylate resins: TSKgel CM-5PW and TSKgel OA-Pak A) as stationary phases in ion-exclusion chromatography for C1-C7 aliphatic carboxylic acids (formic, acetic, propionic, butyric, isovaleric, valeric, isocaproic, caproic, 2-methylhexanoic and heptanoic acids) and benzenecarboxylic acids (pyromellitic, trimellitic, hemimellitic, o-phthalic, m-phthalic, p-phthalic, benzoic, salicylic acids and phenol) was carried out using diluted sulfuric acid as the eluent. Silica-based cation-exchange resins (TSKgel SP-2SW and TSKgel CM-2SW) were very suitable for the ion-exclusion chromatographic separation of these benzenecarboxylic acids. Excellent simultaneous separation of these benzenecarboxylic acids was achieved on a TSKgel SP-2SW column (150 x 6 mm I.D.) in 17 min using a 2.5 mM sulfuric acid at pH 2.4 as the eluent. Polymethacrylate-based cation-exchange resins (TSKgel SP-5PW, TSKgel CM-5PW and TSKgel OA-Pak A) acted as advanced stationary phases for the ion-exclusion chromatographic separation of these C1-C7 aliphatic carboxylic acids. Excellent simultaneous separation of these C1-C7 acids was achieved on a TSKgel CM-5PW column (150 x 6 mm I.D.) in 32 min using a 0.05 mM sulfuric acid at pH 4.0 as the eluent.

Electrochemical Behavior of Sulfur in Aqueous Alkaline Solutions

NASA Astrophysics Data System (ADS)

Mamyrbekova, Aigul; Mamitova, A. D.; Mamyrbekova, Aizhan

2018-03-01

The kinetics and mechanism of the electrode oxidation-reduction of sulfur on an electrically conductive sulfur-graphite electrode in an alkaline solution was studied by the potentiodynamic method. To examine the mechanism of electrode processes occurring during AC polarization on a sulfur-graphite electrode, the cyclic polarization in both directions and anodic polarization curves were recorded. The kinetic parameters: charge transfer coefficients (α), diffusion coefficients ( D), heterogeneous rate constants of electrode process ( k s), and effective activation energies of the process ( E a) were calculated from the results of polarization measurements. An analysis of the results and calculated kinetic parameters of electrode processes showed that discharge ionization of sulfur in alkaline solutions occurs as a sequence of two stages and is a quasireversible process.

Pretreatment of Sugar Beet Pulp with Dilute Sulfurous Acid is Effective for Multipurpose Usage of Carbohydrates.

PubMed

Kharina, M; Emelyanov, V; Mokshina, N; Ibragimova, N; Gorshkova, T

2016-05-01

Sulfurous acid was used for pretreatment of sugar beet pulp (SBP) in order to achieve high efficiency of both extraction of carbohydrates and subsequent enzymatic hydrolysis of the remaining solids. The main advantage of sulfurous acid usage as pretreatment agent is the possibility of its regeneration. Application of sulfurous acid as hydrolyzing agent in relatively low concentrations (0.6-1.0 %) during a short period of time (10-20 min) and low solid to liquid ratio (1:3, 1:6) allowed effective extraction of carbohydrates from SBP and provided positive effect on subsequent enzymatic hydrolysis. The highest obtained concentration of reducing substances (RS) in hydrolysates was 8.5 %; up to 33.6 % of all carbohydrates present in SBP could be extracted. The major obtained monosaccharides were arabinose and glucose (9.4 and 7.3 g/l, respectively). Pretreatment of SBP with sulfurous acid increased 4.6 times the yield of glucose during subsequent enzymatic hydrolysis of remaining solids with cellulase cocktail, as compared to the untreated SBP. Total yield of glucose during SBP pretreatment and subsequent enzymatic hydrolysis amounted to 89.4 % of the theoretical yield. The approach can be applied directly to the wet SBP. Hydrolysis of sugar beet pulp with sulfurous acid is recommended for obtaining of individual monosaccharides, as well as nutritional media.

Ice Nucleation of Bare and Sulfuric Acid-coated Mineral Dust Particles and Implication for Cloud Properties

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

Kulkarni, Gourihar R.; Sanders, Cassandra N.; Zhang, Kai

2014-08-27

Ice nucleation properties of different dust species coated with soluble material are not well understood. We determined the ice nucleation ability of bare and sulfuric acid coated mineral dust particles as a function of temperature (-25 to -35 deg C) and relative humidity with respect to water (RHw). Five different mineral dust species: Arizona test dust (ATD), illite, montmorillonite, quartz and kaolinite were dry dispersed and size-selected at 150 nm and exposed to sulfuric acid vapors in the coating apparatus. The condensed sulfuric acid soluble mass fraction per particle was estimated from the cloud condensation nuclei activated fraction measurements. Themore » fraction of dust particles nucleating ice at various temperatures and RHw was determined using a compact ice chamber. In water-subsaturated conditions, compared to bare dust particles, we found that only coated ATD particles showed suppression of ice nucleation ability while other four dust species did not showed the effect of coating on the fraction of particles nucleating ice. The results suggest that interactions between the dust surface and sulfuric acid vapor are important, such that interactions may or may not modify the surface via chemical reactions with sulfuric acid. At water-supersaturated conditions we did not observed the effect of coating, i.e. the bare and coated dust particles had similar ice nucleation behavior.« less

Effect of sulfuric acid concentration of bentonite and calcination time of pillared bentonite

NASA Astrophysics Data System (ADS)

Mara, Ady; Wijaya, Karna; Trisunaryati, Wega; Mudasir

2016-04-01

An activation of natural clay has been developed. Activation was applied by refluxing the natural bentonite in variation of the sulfuric acid concentration and calcination time of pillared bentonite (PLC). Calcination was applied using oven in microwave 2,45 GHz. Determination of acidity was applied by measuring the amount of adsorbed ammonia and pyridine. Morphological, functional groups and chrystanility characterizations were analyzed using SEM, TEM, FTIR and XRD. Porosity was analyzed using SSA. The results showed that the greater of the concentration of sulfuric acid and calcination time was, the greater the acidity of bentonite as well as the pore diameter were. FTIR spectra showed no fundamental changes in the structure of the natural bentonite, SEM, and TEM images were showing an increase in space or field due to pillarization while the XRD patterns showed a shift to a lower peak. Optimization was obtained at a concentration of 2 M of sulfuric acid and calcination time of 20 minutes, keggin ion of 2.2 and suspension of 10 mmol, respectively each amounted to 11.7490 mmol/gram of ammonia and 2.4437 mmol/gram of pyridine with 154.6391 m2/gram for surface area, 0.130470 m3/gram of pore volume and 3.37484 nm of pore diameter.

A Combined Proteomic and Transcriptomic Analysis on Sulfur Metabolism Pathways of Arabidopsis thaliana under Simulated Acid Rain

PubMed Central

Wang, Wenhua; Simon, Martin; Wu, Feihua; Hu, Wenjun; Chen, Juan B.; Zheng, Hailei

2014-01-01

With rapid economic development, most regions in southern China have suffered acid rain (AR) pollution. In our study, we analyzed the changes in sulfur metabolism in Arabidopsis under simulated AR stress which provide one of the first case studies, in which the systematic responses in sulfur metabolism were characterized by high-throughput methods at different levels including proteomic, genomic and physiological approaches. Generally, we found that all of the processes related to sulfur metabolism responded to AR stress, including sulfur uptake, activation and also synthesis of sulfur-containing amino acid and other secondary metabolites. Finally, we provided a catalogue of the detected sulfur metabolic changes and reconstructed the coordinating network of their mutual influences. This study can help us to understand the mechanisms of plants to adapt to AR stress. PMID:24595051

Roles of sulfuric acid in elemental mercury removal by activated carbon and sulfur-impregnated activated carbon.

PubMed

Morris, Eric A; Kirk, Donald W; Jia, Charles Q; Morita, Kazuki

2012-07-17

This work addresses the discrepancy in the literature regarding the effects of sulfuric acid (H(2)SO(4)) on elemental Hg uptake by activated carbon (AC). H(2)SO(4) in AC substantially increased Hg uptake by absorption particularly in the presence of oxygen. Hg uptake increased with acid amount and temperature exceeding 500 mg-Hg/g-AC after 3 days at 200 °C with AC treated with 20% H(2)SO(4). In the absence of other strong oxidizers, oxygen was able to oxidize Hg. Upon oxidation, Hg was more readily soluble in the acid, greatly enhancing its uptake by acid-treated AC. Without O(2), S(VI) in H(2)SO(4) was able to oxidize Hg, thus making it soluble in H(2)SO(4). Consequently, the presence of a bulk H(2)SO(4) phase within AC pores resulted in an orders of magnitude increase in Hg uptake capacity. However, the bulk H(2)SO(4) phase lowered the AC pore volume and could block the access to the active surface sites and potentially hinder Hg uptake kinetics. AC treated with SO(2) at 700 °C exhibited a much faster rate of Hg uptake attributed to sulfur functional groups enhancing adsorption kinetics. SO(2)-treated carbon maintained its fast uptake kinetics even after impregnation by 20% H(2)SO(4).

Sulfur

USGS Publications Warehouse

Apodaca, L.E.

2012-01-01

In 2011, elemental sulfur and the byproduct sulfuric acid were produced at 109 operations in 29 states and the U.S. Virgin Islands. Total shipments were valued at about $1.6 billion. Elemental sulfur production was 8.2 Mt (9 million st); Louisiana and Texas accounted for about 53 percent of domestic production.

Iron dissolution of dust source materials during simulated acidic processing: the effect of sulfuric, acetic, and oxalic acids.

PubMed

Chen, Haihan; Grassian, Vicki H

2013-09-17

Atmospheric organic acids potentially display different capacities in iron (Fe) mobilization from atmospheric dust compared with inorganic acids, but few measurements have been made on this comparison. We report here a laboratory investigation of Fe mobilization of coal fly ash, a representative Fe-containing anthropogenic aerosol, and Arizona test dust, a reference source material for mineral dust, in pH 2 sulfuric acid, acetic acid, and oxalic acid, respectively. The effects of pH and solar radiation on Fe dissolution have also been explored. The relative capacities of these three acids in Fe dissolution are in the order of oxalic acid > sulfuric acid > acetic acid. Oxalate forms mononuclear bidentate ligand with surface Fe and promotes Fe dissolution to the greatest extent. Photolysis of Fe-oxalate complexes further enhances Fe dissolution with the concomitant degradation of oxalate. These results suggest that ligand-promoted dissolution of Fe may play a more significant role in mobilizing Fe from atmospheric dust compared with proton-assisted processing. The role of atmospheric organic acids should be taken into account in global-biogeochemical modeling to better access dissolved atmospheric Fe deposition flux at the ocean surface.

On the prolonged lifetime of the El Chichon sulfuric acid aerosol cloud

NASA Technical Reports Server (NTRS)

Hofmann, D. J.; Rosen, J. M.

1987-01-01

The observed decay of the aerosol mixing ratio following the eruption of El Chichon appears to have been 20-30 percent slower than that following the eruption of Fuego in 1974, even though the sulfuric acid droplets were observed to grow to considerably larger sizes after El Chichon. This suggests the possible presence of a condensation nuclei and sulfuric acid vapor source and continued growth phenomena occurring well after the El Chichon eruption. It is proposed that the source of these nuclei and the associated vapor may be derived from annual evaporation and condensation of aerosol in the high polar regions during stratospheric warming events, with subsequent spreading to lower latitudes.

Comparison of sulfuric and oxalic acid anodizing for preparation of thermal control coatings for spacecraft

NASA Technical Reports Server (NTRS)

Le, Huong G.; Watcher, John M.; Smith, Charles A.

1988-01-01

The development of thermal control surfaces, which maintain stable solar absorptivity and infrared emissivity over long periods, is challenging due to severe conditions in low-Earth orbit (LEO). Some candidate coatings are second-surface silver-coated Teflon; second-surface, silvered optical solar reflectors made of glass or quartz; and anodized aluminum. Sulfuric acid anodized and oxalic acid anodized aluminum was evaluated under simulated LEO conditions. Oxalic acid anodizing shows promise of greater stability in LEO over long missions, such as the 30 years planned for the Space Station. However, sulfuric acid anodizing shows lower solar absorptivity.

Sulfur-Bearing Phases Detected by Evolved Gas Analysis of the Rocknest Aeolian Deposit, Gale Crater, Mars

NASA Technical Reports Server (NTRS)

Mcadam, Amy Catherine; Franz, Heather Bryant

2014-01-01

The Sample Analysis at Mars (SAM) instrument suite detected SO2, H2S, OCS, and CS2 from approx.450 to 800 C during evolved gas analysis (EGA) of materials from the Rocknest aeolian deposit in Gale Crater, Mars. This was the first detection of evolved sulfur species from a Martian surface sample during in situ EGA. SO2(approx. 3-22 micro-mol) is consistent with the thermal decomposition of Fe sulfates or Ca sulfites, or evolution/desorption from sulfur-bearing amorphous phases. Reactions between reduced sulfur phases such as sulfides and evolved O2 or H2O in the SAM oven are another candidate SO2 source. H2S (approx.41-109 nmol) is consistent with interactions of H2O, H2 and/or HCl with reduced sulfur phases and/or SO2 in the SAM oven. OCS (approx.1-5 nmol) and CS2(approx.0.2-1 nmol) are likely derived from reactions between carbon-bearing compounds and reduced sulfur. Sulfates and sulfites indicate some aqueous interactions, although not necessarily at the Rocknest site; Fe sulfates imply interaction with acid solutions whereas Ca sulfites can form from acidic to near-neutral solutions. Sulfides in the Rocknest materials suggest input from materials originally deposited in a reducing environment or from detrital sulfides from an igneous source. The presence of sulfides also suggests that the materials have not been extensively altered by oxidative aqueous weathering. The possibility of both reduced and oxidized sulfur compounds in the deposit indicates a nonequilibrium assemblage. Understanding the sulfur mineralogy in Rocknest materials, which exhibit chemical similarities to basaltic fines analyzed elsewhere on Mars, can provide insight in to the origin and alteration history of Martian surface materials.

New insights into sulfur amino acids function in gut health and disease

USDA-ARS?s Scientific Manuscript database

The gastrointestinal tract (GIT) is a metabolically significant site of sulfur amino acids (SAAs) metabolism in the body. Aside from their role in protein synthesis, methionine and cysteine are involved in many biological functions and diseases. Methionine (MET) is an indispensable amino acid and is...

Bioreactor for acid mine drainage control

DOEpatents

Zaluski, Marek H.; Manchester, Kenneth R.

2001-01-01

A bioreactor for reacting an aqueous heavy metal and sulfate containing mine drainage solution with sulfate reducing bacteria to produce heavy metal sulfides and reduce the sulfuric acid content of the solution. The reactor is an elongated, horizontal trough defining an inlet section and a reaction section. An inlet manifold adjacent the inlet section distributes aqueous mine drainage solution into the inlet section for flow through the inlet section and reaction section. A sulfate reducing bacteria and bacteria nutrient composition in the inlet section provides sulfate reducing bacteria that with the sulfuric acid and heavy metals in the solution to form solid metal sulfides. The sulfate reducing bacteria and bacteria nutrient composition is retained in the cells of a honeycomb structure formed of cellular honeycomb panels mounted in the reactor inlet section. The honeycomb panels extend upwardly in the inlet section at an acute angle with respect to the horizontal. The cells defined in each panel are thereby offset with respect to the honeycomb cells in each adjacent panel in order to define a tortuous path for the flow of the aqueous solution.

Using heat pipe to make isotherm condition in catalytic converters of sulfuric acid plants

NASA Astrophysics Data System (ADS)

Yousefi, M.; Pahlavanzadeh, H.; Sadrameli, S. M.

2017-08-01

In this study, for the first time, it is tried to construct a pilot reactor, for surveying the possibility of creating isothermal condition in the catalytic convertors where SO2 is converted to SO3 in the sulfuric acid plants by heat pipe. The thermodynamic and thermo-kinetic conditions were considered the same as the sulfuric acid plants converters. Also, influence of SO2 gas flow rate on isothermal condition, has been studied. A thermo-siphon type heat pipe contains the sulfur + 5% iodine as working fluid, was used for disposing the heat of reaction from catalytic bed. Our results show that due to very high energy-efficiency, isothermal and passive heat transfer mechanism of heat pipe, it is possible to reach more than 95% conversion in one isothermal catalytic bed. As the results, heat pipe can be used as a certain piece of equipment to create isothermal condition in catalytic convertors of sulphuric acid plants. With this work a major evaluation in design of sulphuric acid plants can be taken place.

Lithium sulfur batteries and electrolytes and sulfur cathodes thereof

DOEpatents

Visco, Steven J.; Goncharenko, Nikolay; Nimon, Vitaliy; Petrov, Alexei; Nimon, Yevgeniy S.; De Jonghe, Lutgard C.; Katz, Bruce D.; Loginova, Valentina

2017-05-23

Lithium sulfur battery cells that use water as an electrolyte solvent provide significant cost reductions. Electrolytes for the battery cells may include water solvent for maintaining electroactive sulfur species in solution during cell discharge and a sufficient amount of a cycle life-enhancing compound that facilitates charging at the cathode. The combination of these two components enhances one or more of the following cell attributes: energy density, power density and cycle life. For instance, in applications where cost per Watt-Hour (Wh) is paramount, such as grid storage and traction applications, the use of an aqueous electrolyte in combination with inexpensive sulfur as the cathode active material can be a key enabler for the utility and automotive industries, for example, providing a cost effective and compact solution for load leveling, electric vehicles and renewable energy storage. Sulfur cathodes, and methods of fabricating lithium sulfur cells, in particular for loading lithium sulfide into the cathode structures, provide further advantages.

Properties of nanocellulose isolated from corncob residue using sulfuric acid, formic acid, oxidative and mechanical methods.

PubMed

Liu, Chao; Li, Bin; Du, Haishun; Lv, Dong; Zhang, Yuedong; Yu, Guang; Mu, Xindong; Peng, Hui

2016-10-20

In this work, nanocellulose was extracted from bleached corncob residue (CCR), an underutilized lignocellulose waste from furfural industry, using four different methods (i.e. sulfuric acid hydrolysis, formic acid (FA) hydrolysis, 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-mediated oxidation, and pulp refining, respectively). The self-assembled structure, morphology, dimension, crystallinity, chemical structure and thermal stability of prepared nanocellulose were investigated. FA hydrolysis produced longer cellulose nanocrystals (CNCs) than the one obtained by sulfuric acid hydrolysis, and resulted in high crystallinity and thermal stability due to its preferential degradation of amorphous cellulose and lignin. The cellulose nanofibrils (CNFs) with fine and individualized structure could be isolated by TEMPO-mediated oxidation. In comparison with other nanocellulose products, the intensive pulp refining led to the CNFs with the longest length and the thickest diameter. This comparative study can help to provide an insight into the utilization of CCR as a potential source for nanocellulose production. Copyright © 2016 Elsevier Ltd. All rights reserved.

Quantifying hydrogen-deuterium exchange of meteoritic dicarboxylic acids during aqueous extraction

NASA Astrophysics Data System (ADS)

Fuller, M.; Huang, Y.

2003-03-01

Hydrogen isotope ratios of organic compounds in carbonaceous chondrites provide critical information about their origins and evolutionary history. However, because many of these compounds are obtained by aqueous extraction, the degree of hydrogen-deuterium (H/D) exchange that occurs during the process needs to be quantitatively evaluated. This study uses compound- specific hydrogen isotopic analysis to quantify the H/D exchange during aqueous extraction. Three common meteoritic dicarboxylic acids (succinic, glutaric, and 2-methyl glutaric acids) were refluxed under conditions simulating the extraction process. Changes in D values of the dicarboxylic acids were measured following the reflux experiments. A pseudo-first order rate law was used to model the H/D exchange rates which were then used to calculate the isotope exchange resulting from aqueous extraction. The degree of H/D exchange varies as a result of differences in molecular structure, the alkalinity of the extraction solution and presence/absence of meteorite powder. However, our model indicates that succinic, glutaric, and 2-methyl glutaric acids with a D of 1800 would experience isotope changes of 38, 10, and 6, respectively during the extraction process. Therefore, the overall change in D values of the dicarboxylic acids during the aqueous extraction process is negligible. We also demonstrate that H/D exchange occurs on the chiral -carbon in 2-methyl glutaric acid. The results suggest that the racemic mixture of 2-methyl glutaric acid in the Tagish Lake meteorite could result from post-synthesis aqueous alteration. The approach employed in this study can also be used to quantify H/D exchange for other important meteoritic compounds such as amino acids.

A Demonstration of Acid Rain and Lake Acidification: Wet Deposition of Sulfur Dioxide.

ERIC Educational Resources Information Center

Goss, Lisa M.

2003-01-01

Introduces a science demonstration on the dissolution of sulfuric oxide emphasizing the concept of acid rain which is an environmental problem. Demonstrates the acidification from acid rain on two lake environments, limestone and granite. Includes safety information. (YDS)

40 CFR 721.3130 - Sulfuric acid, mono-C9-11-alkyl esters, sodium salts.

Code of Federal Regulations, 2010 CFR

2010-07-01

... (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.3130 Sulfuric acid, mono-C9-11-alkyl esters, sodium salts. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as sulfuric...

Decoupling the Impacts of Heterotrophy and Autotrophy on Sulfuric Acid Speleogenesis

NASA Astrophysics Data System (ADS)

Jones, A. A.; Bennett, P.

2013-12-01

Within caves such as Movile Caves (Romania), the Frasassi Caves (Italy), and Lower Kane Cave (LKC, Wyoming, USA) the combination of abiotic autoxidation and microbiological oxidation of H2S produces SO42- and H+ that promotes limestone dissolution through sulfuric-acid speleogenesis (SAS). Microbial sulfide oxidation by sulfur-oxidizing bacteria (SOB) has been shown recently to be the dominant process leading to speleogenesis in these caves. However, due to the inherently large diversity of microbial communities within these environments, there are a variety of metabolic pathways that can impact limestone dissolution and carbon cycling to varying degrees. In order to investigate these variations we outfitted a continuous flow bioreactor with a Picarro Wavelength-Scanned Cavity Ring Down Spectrometer (WS-CRDS) that continuously monitored and logged 12CO2 and 13CO2 at ppmv sensitivity and isotope ratios at <0.3‰ precision in simulated cave atmospheres. Bioreactors containing Madison Limestone were inoculated with either a monoculture of the mixotrophic sulfur-oxidizing Thiothrix unzii or a mixed environmental (LKC) sulfur-metabolizing community. Ca2+ and pH were also continuously logged in order to quantify the impact of microbial metabolism on limestone dissolution rate. We found an order of magnitude of variability in limestone dissolution rates that were closely tied to microbial metabolism. In monocultures, limestone dissolution was inhibited by excessive reduced sulfur as T. unzii prefers to store sulfur internally as So under these conditions, generating no acidity. The headspace was depleted in 13C when sulfur was being stored as So and enriched in 13C when sulfur was being converted to SO42-. This suggests a preference for a heterotrophy during periods of high sulfur input and autotrophy when sulfur input is low. This was corroborated by an increase in SO42- during low sulfide input and microscope images showed loss of internal sulfur within the filaments

Microbial community structure and sulfur biogeochemistry in mildly-acidic sulfidic geothermal springs in Yellowstone National Park.

PubMed

Macur, R E; Jay, Z J; Taylor, W P; Kozubal, M A; Kocar, B D; Inskeep, W P

2013-01-01

Geothermal and hydrothermal waters often contain high concentrations of dissolved sulfide, which reacts with oxygen (abiotically or biotically) to yield elemental sulfur and other sulfur species that may support microbial metabolism. The primary goal of this study was to elucidate predominant biogeochemical processes important in sulfur biogeochemistry by identifying predominant sulfur species and describing microbial community structure within high-temperature, hypoxic, sulfur sediments ranging in pH from 4.2 to 6.1. Detailed analysis of aqueous species and solid phases present in hypoxic sulfur sediments revealed unique habitats containing high concentrations of dissolved sulfide, thiosulfate, and arsenite, as well as rhombohedral and spherical elemental sulfur and/or sulfide phases such as orpiment, stibnite, and pyrite, as well as alunite and quartz. Results from 16S rRNA gene sequencing show that these sediments are dominated by Crenarchaeota of the orders Desulfurococcales and Thermoproteales. Numerous cultivated representatives of these lineages, as well as the Thermoproteales strain (WP30) isolated in this study, require complex sources of carbon and respire elemental sulfur. We describe a new archaeal isolate (strain WP30) belonging to the order Thermoproteales (phylum Crenarchaeota, 98% identity to Pyrobaculum/Thermoproteus spp. 16S rRNA genes), which was obtained from sulfur sediments using in situ geochemical composition to design cultivation medium. This isolate produces sulfide during growth, which further promotes the formation of sulfide phases including orpiment, stibnite, or pyrite, depending on solution conditions. Geochemical, molecular, and physiological data were integrated to suggest primary factors controlling microbial community structure and function in high-temperature sulfur sediments. © 2012 Blackwell Publishing Ltd.

SULFUR COMPOUNDS IN MORPHOGENESIS.

DTIC Science & Technology

CHICKENS, GROWTH(PHYSIOLOGY), MITOSIS, BACTERIA, ALGAE, LIPOIC ACID , THIOLS, BELGIUM...ORGANIC SULFUR COMPOUNDS, METABOLISM), (*MORPHOLOGY(BIOLOGY), ORGANIC SULFUR COMPOUNDS), (*NUCLEIC ACIDS , BIOSYNTHESIS), EGGS, EMBRYOS, AMPHIBIANS

Potential heat exchange fluids for use in sulfuric acid vaporizers

NASA Technical Reports Server (NTRS)

Lawson, D. D.; Petersen, G. R.

1981-01-01

A series of liquids have been screened as candidate heat exchange fluids for service in thermochemical cycles that involve the vaporization of sulfuric acid. The required chemical and physical criteria of the liquids is described with the results of some preliminary high temperature test data presented.

Redox potentials and kinetics of the Ce 3+/Ce 4+ redox reaction and solubility of cerium sulfates in sulfuric acid solutions

NASA Astrophysics Data System (ADS)

Paulenova, A.; Creager, S. E.; Navratil, J. D.; Wei, Y.

Experimental work was performed with the aim of evaluating the Ce 4+/Ce 3+ redox couple in sulfuric acid electrolyte for use in redox flow battery (RFB) technology. The solubility of cerium sulfates in 0.1-4.0 M sulfuric acid at 20-60 °C was studied. A synergistic effect of both sulfuric acid concentration and temperature on the solubility of cerous sulfate was observed. The solubility of cerous sulfate significantly decreased with rising concentration of sulfuric acid and rising temperature, while the solubility of ceric sulfate goes through a significant maximum at 40 °C. Redox potentials and the kinetics of the cerous/ceric redox reaction were also studied under the same temperature-concentration conditions. The redox potentials were measured using the combined redox electrode (Pt-Ag/AgCl) in equimolar Ce 4+/Ce 3+ solutions (i.e.[Ce 3+]=[Ce 4+]) in sulfuric acid electrolyte. The Ce 3+/Ce 4+ redox potentials significantly decrease (i.e. shift to more negative values) with rising sulfuric acid concentration; a small maximum is observed at 40 °C. Cyclic voltammetric experiments confirmed slow electrochemical kinetics of the Ce 3+/Ce 4+ redox reaction on carbon glassy electrodes (CGEs) in sulfuric acid solutions. The observed dependencies of solubilities, the redox potentials and the kinetics of Ce 3+/Ce 4+ redox reaction on sulfuric acid concentration are thought to be the result of inequivalent complexation of the two redox species by sulfate anions: the ceric ion is much more strongly bound to sulfate than is the cerous ion. The best temperature-concentration conditions for the RFB electrolytes appear to be 40 °C and 1 M sulfuric acid, where the relatively good solubility of both cerium species, the maximum of redox potentials, and the more or less satisfying stability of CGE s were found. Even so, the relatively low solubility of cerium salts in sulfuric acid media and slow redox kinetics of the Ce 3+/Ce 4+ redox reaction at carbon indicate that the Ce 3+/Ce

METHOD OF RECOVERING PLUTONIUM VALUES FROM AQUEOUS SOLUTIONS BY CARRIER PRECIPITATION

DOEpatents

James, R.A.; Thompson, S.G.

1959-11-01

A process is presented for pretreating aqueous nitric acid- plutonium solutions containing a small quantity of hydrazine that has formed as a decomposition product during the dissolution of neutron-bombarded uranium in nitric acid and that impairs the precipitation of plutonium on bismuth phosphate. The solution is digested with alkali metal dichromate or potassium permanganate at between 75 and 100 deg C; sulfuric acid at approximately 75 deg C and sodium nitrate, oxaiic acid plus manganous nitrate, or hydroxylamine are added to the solution to secure the plutonium in the tetravalent state and make it suitable for precipitation on BiPO/sub 4/.

Coal desulfurization by aqueous chlorination

NASA Technical Reports Server (NTRS)

Kalvinskas, J. J.; Vasilakos, N.; Corcoran, W. H.; Grohmann, K.; Rohatgi, N. K. (Inventor)

1982-01-01

A method of desulfurizing coal is described in which chlorine gas is bubbled through an aqueous slurry of coal at low temperature below 130 degrees C., and at ambient pressure. Chlorinolysis converts both inorganic and organic sulfur components of coal into water soluble compounds which enter the aqueous suspending media. The media is separated after chlorinolysis and the coal dechlorinated at a temperature of from 300 C to 500 C to form a non-caking, low-sulfur coal product.

Aqueous Alteration on Mars: Evidence from Landed Missions

NASA Technical Reports Server (NTRS)

Ming, Douglas W.; Morris, Richard V.; Clark, Benton C., III; Yen, Albert S.; Gellert, Ralf

2015-01-01

Mineralogical and geochemical data returned by orbiters and landers over the past 15 years have substantially enhanced our understanding of the history of aqueous alteration on Mars. Here, we summarize aqueous processes that have been implied from data collected by landed missions. Mars is a basaltic planet. The geochemistry of most materials has not been “extensively” altered by open-system aqueous processes and have average Mars crustal compositions. There are few examples of open-system alteration, such as Gale crater’s Pahrump Hills mudstone. Types of aqueous alteration include (1) acid-sulfate and (2) hydrolytic (circum-neutral/alkaline pH) with varying water-to-rock ratios. Several hypotheses have been suggested for acid-sulfate alteration including (1) oxidative weathering of ultramafic igneous rocks containing sulfides; (2) sulfuric acid weathering of basaltic materials; (3) acid fog weathering of basaltic materials; and (4) near-neutral pH subsurface solutions rich in Fe (sup 2 plus) that rapidly oxidized to Fe (sup 3 plus) producing excess acidity. Meridiani Planum’s sulfate-rich sedimentary deposit containing jarosite is the most “famous” acid-sulfate environment visited on Mars, although ferric sulfate-rich soils are common in Gusev crater’s Columbia Hills and jarosite was recently discovered in the Pahrump Hills. An example of aqueous alteration under circum-neutral pH conditions is the formation of Fe-saponite with magnetite in situ via aqueous alteration of olivine in Gale crater’s Sheepbed mudstone. Circum-neutral pH, hydrothermal conditions were likely required for the formation of Mg-Fe carbonate in the Columbia Hills. Diagenetic features (e.g., spherules, fracture filled veins) indicate multiple episodes of aqueous alteration/diagenesis in most sedimentary deposits. However, low water-to-rock ratios are prominent at most sites visited by landed missions (e.g., limited water for reaction to form crystalline phases possibly

Inhibition of enzymatic browning of chlorogenic acid by sulfur-containing compounds.

PubMed

Kuijpers, Tomas F M; Narváez-Cuenca, Carlos-Eduardo; Vincken, Jean-Paul; Verloop, Annewieke J W; van Berkel, Willem J H; Gruppen, Harry

2012-04-04

The antibrowning activity of sodium hydrogen sulfite (NaHSO(3)) was compared to that of other sulfur-containing compounds. Inhibition of enzymatic browning was investigated using a model browning system consisting of mushroom tyrosinase and chlorogenic acid (5-CQA). Development of brown color (spectral analysis), oxygen consumption, and reaction product formation (RP-UHPLC-PDA-MS) were monitored in time. It was found that the compounds showing antibrowning activity either prevented browning by forming colorless addition products with o-quinones of 5-CQA (NaHSO(3), cysteine, and glutathione) or inhibiting the enzymatic activity of tyrosinase (NaHSO(3) and dithiothreitol). NaHSO(3) was different from the other sulfur-containing compounds investigated, because it showed a dual inhibitory effect on browning. Initial browning was prevented by trapping the o-quinones formed in colorless addition products (sulfochlorogenic acid), while at the same time, tyrosinase activity was inhibited in a time-dependent way, as shown by pre-incubation experiments of tyrosinase with NaHSO(3). Furthermore, it was demonstrated that sulfochlorogenic and cysteinylchlorogenic acids were not inhibitors of mushroom tyrosinase.

Large discharge capacity from carbon electrodes in sulfuric acid with oxidant

NASA Astrophysics Data System (ADS)

Inagaki, M.; Iwashita, N.

The discharge performance of the graphite intercalation compounds in sulfuric acid containing nitric acid (H 2SO 4-GICs) was studied by focusing on the effects of oxidant and carbon nanotexture. A large discharge capacity from H 2SO 4-GICs synthesized by using an excess amount of HNO 3, more than 150 times of the theoretical value (93 mAh/g carbon), was obtained depending on the amount of oxidant added, the discharge current, and the nanotexture of carbon electrode. The experimental results are explained in terms of competition between the de-intercalation of sulfuric acid due to galvanostatic reduction and the re-intercalation due to chemical oxidation by HN03 during discharging. However, a subsidiary reaction decreases the effective amount of HNO 3 on the discharge by a small current and also on the cycle of chemical charging and electrochemical discharging. The oxidant KMnO 4 gave only a little larger capacity for discharge than the theoretical one, because it was reduced to the manganese oxide precipitates during the oxidation of the carbon electrode.

Delayed production of sulfuric acid condensation nuclei in the polar stratosphere from El Chichon volcanic vapors

NASA Technical Reports Server (NTRS)

Hofmann, D. J.; Rosen, J. M.; Gringel, W.

1985-01-01

It is pointed out that measurements of the vertical profiles of atmospheric condensation nuclei (CN) have been conducted since 1973. Studies with a new instrument revealed that the CN concentration undergoes a remarkable annual variation in the 30-km region characterized by a large increase in the late winter/early spring period with a subsequent decay during the remainder of the year. The event particles are observed to be volatile at 150 C, suggesting a sulfuric acid-water composition similar to that found in the normal 20 km aerosol layer. The development of about 10 to the 7th metric tons of sulfuric acid aerosol following the injection of sulfurous gases by El Chichon in April 1982, prompted Hofmann and Rosen (1983) to predict a very large CN event for 1983. The present investigation is concerned with the actual observation of the predicted event. Attention is given to the observation of a very large increase of what appear to be small sulfuric acid droplets at 30-km altitude in January 1983 over Laramie, WY, in January 1983.

Sulfur Assimilation in Developing Lupin Cotyledons Could Contribute Significantly to the Accumulation of Organic Sulfur Reserves in the Seed

PubMed Central

Tabe, Linda Marie; Droux, Michel

2001-01-01

It is currently assumed that the assimilation of sulfur into reduced forms occurs predominantly in the leaves of plants. However, developing seeds have a strong requirement for sulfur amino acids for storage protein synthesis. We have assessed the capacity of developing seeds of narrow-leaf lupin (Lupinus angustifolius) for sulfur assimilation. Cotyledons of developing lupin seeds were able to transfer the sulfur atom from 35S-labeled sulfate into seed proteins in vitro, demonstrating the ability of the developing cotyledons to perform all the steps of sulfur reduction and sulfur amino acid biosynthesis. Oxidized sulfur constituted approximately 30% of the sulfur in mature seeds of lupins grown in the field and almost all of the sulfur detected in phloem exuded from developing pods. The activities of three enzymes of the sulfur amino acid biosynthetic pathway were found in developing cotyledons in quantities theoretically sufficient to account for all of the sulfur amino acids that accumulate in the protein of mature lupin seeds. We conclude that sulfur assimilation by developing cotyledons is likely to be an important source of sulfur amino acids for the synthesis of storage proteins during lupin seed maturation. PMID:11351081

Sulfur assimilation in developing lupin cotyledons could contribute significantly to the accumulation of organic sulfur reserves in the seed.

PubMed

Tabe, L M; Droux, M

2001-05-01

It is currently assumed that the assimilation of sulfur into reduced forms occurs predominantly in the leaves of plants. However, developing seeds have a strong requirement for sulfur amino acids for storage protein synthesis. We have assessed the capacity of developing seeds of narrow-leaf lupin (Lupinus angustifolius) for sulfur assimilation. Cotyledons of developing lupin seeds were able to transfer the sulfur atom from 35S-labeled sulfate into seed proteins in vitro, demonstrating the ability of the developing cotyledons to perform all the steps of sulfur reduction and sulfur amino acid biosynthesis. Oxidized sulfur constituted approximately 30% of the sulfur in mature seeds of lupins grown in the field and almost all of the sulfur detected in phloem exuded from developing pods. The activities of three enzymes of the sulfur amino acid biosynthetic pathway were found in developing cotyledons in quantities theoretically sufficient to account for all of the sulfur amino acids that accumulate in the protein of mature lupin seeds. We conclude that sulfur assimilation by developing cotyledons is likely to be an important source of sulfur amino acids for the synthesis of storage proteins during lupin seed maturation.

Comparison of sulfuric and hydrochloric acids as catalysts in hydrolysis of Kappaphycus alvarezii (cottonii).

PubMed

Meinita, Maria Dyah Nur; Hong, Yong-Ki; Jeong, Gwi-Taek

2012-01-01

In this study, hydrolysis of marine algal biomass Kappaphhycus alvarezii using two different acid catalysts was examined with the goal of identifying optimal reaction conditions for the formation of sugars and by-products. K. alvarezii were hydrolyzed by autoclave using sulfuric acid or hydrochloric acid as catalyst with different acid concentrations (0.1-1.0 M), substrate concentrations (1.0-13.5%), hydrolysis time (10-90 min) and hydrolysis temperatures (100-130 (°)C). A difference in galactose, glucose, reducing sugar and total sugar content was observed under the different hydrolysis conditions. Different by-product compounds such as 5-hydroxymethylfurfural and levulinic acid were also observed under the different reaction conditions. The optimal conditions for hydrolysis were achieved at a sulfuric acid concentration, temperature and reaction time of 0.2 M, 130 °C and 15 min, respectively. These results may provide useful information for the development of more efficient systems for biofuel production from marine biomass.

Supercritical carbon dioxide and sulfur in the Madison Limestone: A natural analog in southwest Wyoming for geologic carbon-sulfur co-sequestration

NASA Astrophysics Data System (ADS)

Kaszuba, John P.; Navarre-Sitchler, Alexis; Thyne, Geoffrey; Chopping, Curtis; Meuzelaar, Tom

2011-09-01

The Madison Limestone on the Moxa Arch, southwest Wyoming, USA contains large volumes (65-95%) of supercritical CO 2 that it has stored naturally for 50 million years. This reservoir also contains supercritical H 2S, aqueous sulfur complexes (SO 42- and HS -), and sulfur-bearing minerals (anhydrite and pyrite). Although SO 2 is not present, these sulfur-bearing phases are known products of SO 2 disproportionation in other water-rock systems. The natural co-occurrence of SO 42-, S 2-, supercritical CO 2 and brine affords the opportunity to evaluate the fate of a carbon-sulfur co-sequestration scenario. Mineralogic data was obtained from drill core and aqueous geochemical data from wells outside and within the current supercritical CO 2-sulfur-brine-rock system. In addition to dolomite, calcite, and accessory sulfur-bearing minerals, the Madison Limestone contains accessory quartz and the aluminum-bearing minerals feldspar, illite, and analcime. Dawsonite (NaAlCO 3(OH) 2), predicted as an important carbon sink in sequestration modeling studies, is not present. After confirming equilibrium conditions for the Madison Limestone system, reaction path models were constructed with initial conditions based on data from outside the reservoir. Addition of supercritical CO 2 to the Madison Limestone was simulated and the results compared to data from inside the reservoir. The model accurately predicts the observed mineralogy and captures the fundamental changes expected in a Madison Limestone-brine system into which CO 2 is added. pH decreases from 5.7 to 4.5 at 90 °C and to 4.0 at 110 °C, as expected from dissolution of supercritical CO 2, creation of carbonic acid, and buffering by the carbonate rock. The calculated redox potential increases by 0.1 V at 90 °C and 0.15 V at 110 °C due to equilibrium among CO 2, anhydrite, and pyrite. Final calculated Eh and pH match conditions for the co-existing sulfur phases present in produced waters and core from within the reservoir

Experimental Acid Weathering of Fe-Bearing Mars Analog Minerals and Rocks: Implications for Aqueous Origin of Hematite-Bearing Sediments in Meridiani Planum, Mars

NASA Technical Reports Server (NTRS)

Golden, D. C.; Koster, A. M.; Ming, D. W.; Morris, R. V.; Mertzman, S. A.

2011-01-01

A working hypothesis for Meridiani evaporite formation involves the evaporation of fluids derived from acid weathering of Martian basalts and subsequent diagenesis [1, 2]. However, there are no reported experimental studies for the formation of jarosite and gray hematite (spherules), which are characteristic of Meridiani rocks from Mars analog precursor minerals. A terrestrial analog for hematite spherule formation from basaltic rocks under acidic hydrothermal conditions has been reported [3], and we have previously shown that the hematite spherules and jarosite can be synthetically produced in the laboratory using Fe3+ -bearing sulfate brines under hydrothermal conditions [4]. Here we expand and extend these studies by reacting Mars analog minerals with sulfuric acid to form Meridiani-like rock-mineral compositions. The objective of this study is to provide environmental constraints on past aqueous weathering of basaltic materials on Mars.

Polymerization of beta-amino acids in aqueous solution

NASA Technical Reports Server (NTRS)

Liu, R.; Orgel, L. E.; Bada, J. L. (Principal Investigator)

1998-01-01

We have compared carbonyl diimidazole (CDI) and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDAC) as activating agents for the oligomerization of negatively-charged alpha- and beta-amino acids in homogeneous aqueous solution. alpha-Amino acids can be oligomerized efficiently using CDI, but not by EDAC. beta-Amino acids can be oligomerized efficiently using EDAC, but not by CDI. Aspartic acid, an alpha- and beta-dicarboxylic acid is oligomerized efficiently by both reagents. These results are explained in terms of the mechanisms of the reactions, and their relevance to prebiotic chemistry is discussed.

Preparation of sulfonic acid-containing rubbers from natural rubber vulcanizates

NASA Astrophysics Data System (ADS)

Poonsawat, Worapong; Poompradub, Sirilux; Ngamcharussrivichai, Chawalit

2014-06-01

In this work, a series of sulfonic acid-containing rubbers were prepared by aqueous phase oxidation of natural rubber vulcanizates in the presence of hydrogen peroxide (H2O2) and formic acid (HCOOH). The starting vulcanizates were neatly prepared via an efficient vulcanization (EV) system by varying mass ratio of N-cyclohexyl-2-benzothiazole sulfonamide (CBS), as an accelerator, to sulfur. The oxidation conditions were controlled at the molar ratio of H2O2: HCOOH = 1:1, the concentration of H2O2 = 15 wt.%, the temperature = 50 °C, and the reaction time = 3 h. The rubber materials before and after the oxidation were characterized for their physicochemical properties by using Fourier transform infrared spectroscopy, bomb calorimetry, acid-base titration and swelling measurements. The results indicated the presence of sulfonic acid group in the oxidized rubbers, generated by the oxidative cleaves of sulfide crosslinks in the rubber vulcanizates. The oxidation decreased the sulfur content of the rubber in which the level of sulfur loss was determined by the CBS/sulfur ratio. Moreover, the acidity of the oxidized products was correlated with the amount of sulfur remaining.

Friction and wear of nickel in sulfuric acid

NASA Technical Reports Server (NTRS)

Rengstorff, G. W. P.; Miyoshi, K.; Buckley, D. H.

1984-01-01

Experiments were conducted with elemental nickel sliding on aluminum oxide in aerated sulfuric acid in concentrations ranging from very dilute (10 -4 N, i.e., 5 ppm) to very concentrated (96 percent) acid. Load and reciprocating sliding speeds were kept constant. With the most dilute concentration (10 -4 N) no observable corrosion occurred in or outside the wear area. This was used as the base condition to determine the high contribution of corrosion to total wear loss at acid concentrations between 0.5 percent (0.1 N) and 75 percent. Corrosion reached a maximum rate of 100 millimeters per year at 30 percent acid. At the same time, general corrosion outside the wear area was very low, in agreement with published information. It is clear that friction and wear greatly accelerated corrosion in the wear area. At dilute concentrations of 0.001 and 0.01 N, corrosion in the wear area was low, and general corrosion outside was also low, but local outside regions in the direction of the wear motion experienced some enhanced corrosion, apparently due to fluid motion of the acid.

Dynamic behavior of the bray-liebhafsky oscillatory reaction controlled by sulfuric acid and temperature

NASA Astrophysics Data System (ADS)

Pejić, N.; Vujković, M.; Maksimović, J.; Ivanović, A.; Anić, S.; Čupić, Ž.; Kolar-Anić, Lj.

2011-12-01

The non-periodic, periodic and chaotic regimes in the Bray-Liebhafsky (BL) oscillatory reaction observed in a continuously fed well stirred tank reactor (CSTR) under isothermal conditions at various inflow concentrations of the sulfuric acid were experimentally studied. In each series (at any fixed temperature), termination of oscillatory behavior via saddle loop infinite period bifurcation (SNIPER) as well as some kind of the Andronov-Hopf bifurcation is presented. In addition, it was found that an increase of temperature, in different series of experiments resulted in the shift of bifurcation point towards higher values of sulfuric acid concentration.

Catalytic conversion of carbohydrates to 5-hydroxymethylfurfural from the waste liquid of acid hydrolysis NCC.

PubMed

Sun, Yonghui; Liu, Pengtao; Liu, Zhong

2016-05-20

The principal goal of this work was to reuse the carbohydrates and recycle sulfuric acid in the waste liquid of acid hydrolysis nanocrystalline cellulose (NCC). Therefore, in this work, the optimizations of further hydrolysis of waste liquid of acid hydrolysis NCC and catalytic conversion of L4 to 5-hydroxymethylfurfural (5-HMF) were studied. Sulfuric acid was separated by spiral wound diffusion dialysis (SWDD). The results revealed that cellulose can be hydrolyze to glucose absolutely under the condition of temperature 35 °C, 3 h, and sulfuric acid's concentration 62 wt%. And 78.3% sulfuric acid was recovered by SWDD. The yield of 5-HMF was highest in aqueous solution under the optimal condition was as follows, temperature 160 °C, 3 h, and sulfuric acid's concentration 12 wt%. Then the effect of biphasic solvent systems catalytic conversion and inorganic salt as additives were still examined. The results showed that both of them contributed to prepare 5-HMF. The yield and selectivity of 5-HMF was up to 21.0% and 31.4%, respectively. Copyright © 2016 Elsevier Ltd. All rights reserved.

Sulfuric acid baking and leaching of spent Co-Mo/Al2O3 catalyst.

PubMed

Kim, Hong-In; Park, Kyung-Ho; Mishra, Devabrata

2009-07-30

Dissolution of metals from a pre-oxidized refinery plant spent Co-Mo/Al(2)O(3) catalyst have been tried through low temperature (200-450 degrees C) sulfuric acid baking followed by mild leaching process. Direct sulfuric acid leaching of the same sample, resulted poor Al and Mo recoveries, whereas leaching after sulfuric acid baking significantly improved the recoveries of above two metals. The pre-oxidized spent catalyst, obtained from a Korean refinery plant found to contain 40% Al, 9.92% Mo, 2.28% Co, 2.5% C and trace amount of other elements such as Fe, Ni, S and P. XRD results indicated the host matrix to be poorly crystalline gamma- Al(2)O(3). The effect of various baking parameters such as catalyst-to-acid ratio, baking temperature and baking time on percentage dissolutions of metals has been studied. It was observed that, metals dissolution increases with increase in the baking temperature up to 300 degrees C, then decreases with further increase in the baking temperature. Under optimum baking condition more than 90% Co and Mo, and 93% Al could be dissolved from the spent catalyst with the following leaching condition: H(2)SO(4)=2% (v/v), temperature=95 degrees C, time=60 min and Pulp density=5%.

Process for removing sulfur from sulfur-containing gases: high calcium fly-ash

DOEpatents

Rochelle, Gary T.; Chang, John C. S.

1991-01-01

The present disclosure relates to improved processes for treating hot sulfur-containing flue gas to remove sulfur therefrom. Processes in accordance with the present invention include preparing an aqueous slurry composed of a calcium alkali source and a source of reactive silica and/or alumina, heating the slurry to above-ambient temperatures for a period of time in order to facilitate the formation of sulfur-absorbing calcium silicates or aluminates, and treating the gas with the heat-treated slurry components. Examples disclosed herein demonstrate the utility of these processes in achieving improved sulfur-absorbing capabilities. Additionally, disclosure is provided which illustrates preferred configurations for employing the present processes both as a dry sorbent injection and for use in conjunction with a spray dryer and/or bagfilter. Retrofit application to existing systems is also addressed.

ELEMENTAL MERCURY ADSORPTION BY ACTIVATED CARBON TREATED WITH SULFURIC ACID

EPA Science Inventory

The paper gives results of a study of the adsorption of elemental mercury at 125 C by a sulfuric-acid (H2S04, 50% w/w/ solution)-treated carbon for the removal of mercury from flue gas. The pore structure of the sample was characterized by nitrogen (N2) at -196 C and the t-plot m...

Acidities of Water and Methanol in Aqueous Solution and DMSO

ERIC Educational Resources Information Center

Gao, Daqing

2009-01-01

The relative acidities of water and methanol have been a nagging issue. In gas phase, methanol is more acidic than water by 36.0 kJ/mol; however, in aqueous solution, the acidities of methanol and water are almost identical. The acidity of an acid in solution is determined by both the intrinsic gas-phase ionization Gibbs energy and the solvent…

Heterogeneous chemistry of alkylamines with sulfuric acid: implications for atmospheric formation of alkylaminium sulfates.

PubMed

Wang, Lin; Lal, Vinita; Khalizov, Alexei F; Zhang, Renyi

2010-04-01

The heterogeneous interaction of alkylamines with sulfuric acid has been investigated to assess the role of amines in aerosol growth through the formation of alkylaminium sulfates. The kinetic experiments were conducted in a low-pressure fast flow reactor coupled to an ion drift-chemical ionization mass spectrometer (ID-CIMS). The measurements of heterogeneous uptake of methylamine, dimethylamine, and trimethylamine were performed in the acidity range of 59-82 wt % H(2)SO(4) and between 243 and 283 K. Irreversible reactive uptakes were observed for all three alkylamines, with comparable uptake coefficients (gamma) in the range of 2.0 x 10(-2) to 4.4 x 10(-2). The measured gamma value was slightly higher in more concentrated sulfuric acid and at lower temperatures. The results imply that the heterogeneous reactions of alkylamines contribute effectively to the growth of atmospheric acidic particles and, hence, secondary organic aerosol formation.

Treatment of infectious skin defects or ulcers with electrolyzed strong acid aqueous solution.

PubMed

Sekiya, S; Ohmori, K; Harii, K

1997-01-01

A chronic ulcer with an infection such as methicillin-resistant Staphylococcus aureus is hard to heal. Plastic and reconstructive surgeons often encounter such chronic ulcers that are resistant to surgical or various conservative treatments. We applied conservative treatment using an electrolyzed strong acid aqueous solution and obtained satisfactory results. The lesion was washed with the solution or soaked in a bowl of the solution for approximately 20 min twice a day. Fresh electrolyzed strong acid aqueous solution is unstable and should be stored in a cool, dark site in a sealed bottle. It should be used within a week after it has been produced. Here we report on 15 cases of infectious ulcers that were treated by electrolyzed strong acid aqueous solution. Of these cases, 7 patients were healed, 3 were granulated, and in 5, infection subsided. In most cases the lesion became less reddish and less edematous. Discharge or foul odor from the lesion was decreased. Electrolyzed strong acid aqueous solution was especially effective for treating a chronic refractory ulcer combined with diabetes melitus or peripheral circulatory insufficiency. This clinically applied therapy of electrolyzed strong acid aqueous solution was found to be effective so that this new therapeutic technique for ulcer treatment can now be conveniently utilized.

Characterization of the Aqueous Fractions from Hydrotreatment and Hydrothermal Liquefaction of Lignocellulosic Feedstocks

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

Panisko, Ellen A.; Wietsma, Thomas W.; Lemmon, Teresa L.

In this study the aqueous phases resulting from the hydrothermal liquefaction of biomass and the hydrotreatment of fast pyrolysis bio-oils were analyzed via TC, COD, GC-MS, GC-FID, HPLC, and ICP-OES to determine the organic and inorganic species present and the quantitative amounts of each. This work is necessary to address a significant knowledge gap in the literature related to the aqueous phases from thermochemical processes. Results showed that water from the hydrotreatment of eight different bio-oils contained less than 1 wt% total carbon, in many cases less than 0.2%. Negligible organic carbon was observed. Hydrothermal liquefaction samples contained between 1-2more » wt% carbon, accounting for 34 – 45% of the total carbon sent to the reactor. The majority of this carbon was present as acids, with glycolic acid and acetic acid having the highest concentrations. Alcohols, specifically methanol and ethanol, were also present. Numerous ketones were observed, consisting of mainly acetone and cyclopenta-ones. The amount of the total carbon identified and quantified in the HTL samples ranged from 64 – 82%. Inorganic species present in the HT samples were sodium, silicon, and sulfur. The highest levels of sulfur were observed in the grasses and agricultural residue (corn stover). The HTL samples exhibited much higher inorganic content, with very high levels of sodium and potassium. Alkali and alkali earth metals, as well as sulfur, were also present at levels high enough to raise concerns for the use of catalysts in downstream upgrading or reforming processes.« less

Resistance of biofilm-covered mortars to microbiologically influenced deterioration simulated by sulfuric acid exposure

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

Soleimani, Sahar, E-mail: ssoleima@connect.carleton.ca; Isgor, O. Burkan, E-mail: burkan_isgor@carleton.ca; Ormeci, Banu, E-mail: banu_ormeci@carleton.ca

2013-11-15

Following the reported success of biofilm applications on metal surfaces to inhibit microbiologically influenced corrosion, effectiveness and sustainability of E. coli DH5α biofilm on mortar surface to prevent microbiologically influenced concrete deterioration (MICD) are investigated. Experiments simulating microbial attack were carried out by exposing incrementally biofilm-covered mortar specimens to sulfuric acid solutions with pH ranging from 3 to 6. Results showed that calcium concentration in control reactors without biofilm was 23–47% higher than the reactors with biofilm-covered mortar. Formation of amorphous silica gel as an indication of early stages of acid attack was observed only on the control mortar specimensmore » without biofilm. During acidification, the biofilm continued to grow and its thickness almost doubled from ∼ 30 μm before acidification to ∼ 60 μm after acidification. These results demonstrated that E. coli DH5α biofilm was able to provide a protective and sustainable barrier on mortar surfaces against medium to strong sulfuric acid attack. -- Highlights: •Effectiveness of E.coli DH5α biofilm to prevent MICD was studied. •Conditions that lead to MICD were simulated by chemical acidification. •Biofilm-covered mortar specimens were exposed to sulfuric acid solutions. •The presence of biofilm helped reduce the chemically-induced mortar deterioration. •Biofilm remained alive and continued to grow during the acidification process.« less

Heterogeneous interactions of chlorine nitrate, hydrogen chloride, and nitric acid with sulfuric acid surfaces at stratospheric temperatures

NASA Technical Reports Server (NTRS)

Tolbert, Margaret A.; Rossi, Michel J.; Golden, David M.

1988-01-01

The heterogeneous interactions of ClONO2, HCl, and HNO3 with sulfuric acid surfaces were studied using a Knudsen cell flow reactor. The surfaces studied, chosen to simulate global stratospheric particulate, were composed of 65-75 percent H2SO4 solutions at temperatures in the range -63 to -43 C. Heterogeneous loss, but not reaction, of HNO3 and HCl occurred on these surfaces; the measured sticking coefficients are reported. Chlorine nitrate reacted on the cold sulfuric acid surfaces, producing gas-phase HOCl and condensed HNO3. CLONO2 also reacted with HCl dissolved in the 65-percent H2SO4 solution at -63 C, forming gaseous Cl2. In all cases studied, the sticking and/or reaction coefficients were much larger for the 65-percent H2SO4 solution at -63 C than for the 75-percent solution at -43 C.

Analysis of organic sulfur compounds in atmospheric aerosols at the HKUST supersite in Hong Kong using HR-ToF-AMS.

PubMed

Huang, Dan Dan; Li, Yong Jie; Lee, Berto P; Chan, Chak K

2015-03-17

Organic sulfur compounds have been identified in ambient secondary organic aerosols, but their contribution to organic mass is not well quantified. In this study, using a high-resolution time-of-flight aerosol mass spectrometer (AMS), concentrations of organic sulfur compounds were estimated based on the high-resolution fragmentation patterns of methanesulfonic acid (MSA), and organosulfates (OS), including alkyl, phenyl, and cycloalkyl sulfates, obtained in laboratory experiments. Mass concentrations of MSA and minimum mass concentrations of OS were determined in a field campaign conducted at a coastal site of Hong Kong in September 2011. MSA and OS together accounted for at least 5% of AMS detected organics. MSA is of marine origin with its formation dominated by local photochemical activities and enhanced by aqueous phase processing. OS concentrations are better correlated with particle liquid water content (LWC) than with particle acidity. High-molecular-weight OS were detected in the continental influenced period probably because they had grown into larger molecules during long-range transport or they were formed from large anthropogenic precursors. This study highlights the importance of both aqueous-phase processing and regional influence, i.e., different air mass origins, on organic sulfur compound formation in coastal cities like Hong Kong.

Comparing the performance of Miscanthus x giganteus and wheat straw biomass in sulfuric acid based pretreatment.

PubMed

Kärcher, M A; Iqbal, Y; Lewandowski, I; Senn, T

2015-03-01

The objective of this study was to assess and compare the suitability of Miscanthus x giganteus and wheat straw biomass in dilute acid catalyzed pretreatment. Miscanthus and wheat straw were treated in a dilute sulfuric acid/steam explosion pretreatment. As a result of combining dilute sulfuric acid- and steam explosion pretreatment the hemicellulose hydrolysis yields (96% in wheat straw and 90% in miscanthus) in both substrates were higher than reported in literature. The combined severity factor (=CSF) for optimal hemicellulose hydrolysis was 1.9 and 1.5 in for miscanthus and wheat straw respectively. Because of the higher CSF value more furfural, furfuryl alcohol, 5-hydroxymethylfurfural and acetic acid was formed in miscanthus than in wheat straw pretreatment. Copyright © 2015 Elsevier Ltd. All rights reserved.

Sulfuric acid and hydrogen peroxide surface passivation effects on AlGaN/GaN high electron mobility transistors

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

Zaidi, Z. H., E-mail: zaffar.zaidi@sheffield.ac.uk; Lee, K. B.; Qian, H.

2014-12-28

In this work, we have compared SiN{sub x} passivation, hydrogen peroxide, and sulfuric acid treatment on AlGaN/GaN HEMTs surface after full device fabrication on Si substrate. Both the chemical treatments resulted in the suppression of device pinch-off gate leakage current below 1 μA/mm, which is much lower than that for SiN{sub x} passivation. The greatest suppression over the range of devices is observed with the sulfuric acid treatment. The device on/off current ratio is improved (from 10{sup 4}–10{sup 5} to 10{sup 7}) and a reduction in the device sub-threshold (S.S.) slope (from ∼215 to 90 mV/decade) is achieved. The sulfuric acid ismore » believed to work by oxidizing the surface which has a strong passivating effect on the gate leakage current. The interface trap charge density (D{sub it}) is reduced (from 4.86 to 0.90 × 10{sup 12 }cm{sup −2} eV{sup −1}), calculated from the change in the device S.S. The gate surface leakage current mechanism is explained by combined Mott hopping conduction and Poole Frenkel models for both untreated and sulfuric acid treated devices. Combining the sulfuric acid treatment underneath the gate with the SiN{sub x} passivation after full device fabrication results in the reduction of D{sub it} and improves the surface related current collapse.« less

Degradation of self-compacting concrete (SCC) due to sulfuric acid attack: Experiment investigation on the effect of high volume fly ash content

NASA Astrophysics Data System (ADS)

Kristiawan, S. A.; Sunarmasto; Tyas, G. P.

2016-02-01

Concrete is susceptible to a variety of chemical attacks. In the sulfuric acid environment, concrete is subjected to a combination of sulfuric and acid attack. This research is aimed to investigate the degradation of self-compacting concrete (SCC) due to sulfuric acid attack based on measurement of compressive strength loss and diameter change. Since the proportion of SCC contains higher cement than that of normal concrete, the vulnerability of this concrete to sulfuric acid attack could be reduced by partial replacement of cement with fly ash at high volume level. The effect of high volume fly ash at 50-70% cement replacement levels on the extent of degradation owing to sulfuric acid will be assessed in this study. It can be shown that an increase in the utilization of fly ash to partially replace cement tends to reduce the degradation as confirmed by less compressive strength loss and diameter change. The effect of fly ash to reduce the degradation of SCC is more pronounced at a later age.

Dynamics of a Sonoluminescing Bubble in Sulfuric Acid

NASA Astrophysics Data System (ADS)

Hopkins, Stephen D.; Putterman, Seth J.; Kappus, Brian A.; Suslick, Kenneth S.; Camara, Carlos G.

2005-12-01

The spectral shape and observed sonoluminescence emission from Xe bubbles in concentrated sulfuric acid is consistent only with blackbody emission from a spherical surface that fills the bubble. The interior of the observed 7000 K blackbody must be at least 4 times hotter than the emitting surface in order that the equilibrium light-matter interaction length be smaller than the radius. Bright emission is correlated with long emission times (˜10ns), sharp thresholds, unstable translational motion, and implosions that are sufficiently weak that contributions from the van der Waals hard core are small.

Dynamics of a sonoluminescing bubble in sulfuric acid.

PubMed

Hopkins, Stephen D; Putterman, Seth J; Kappus, Brian A; Suslick, Kenneth S; Camara, Carlos G

2005-12-16

The spectral shape and observed sonoluminescence emission from Xe bubbles in concentrated sulfuric acid is consistent only with blackbody emission from a spherical surface that fills the bubble. The interior of the observed 7000 K blackbody must be at least 4 times hotter than the emitting surface in order that the equilibrium light-matter interaction length be smaller than the radius. Bright emission is correlated with long emission times (approximately 10 ns), sharp thresholds, unstable translational motion, and implosions that are sufficiently weak that contributions from the van der Waals hard core are small.

Compact regenerable sulfur scrubber for phosphoric acid fuel cells. Final report, 30 September 1986-30 September 1987

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

Giner, J.; Cropley, C.C.

Technology for the direct desulfurization of unprocessed diesel fuel using regenerable copper-based mixed metal oxide sorbents was developed for incorporation in modular phosphoric acid fuel cell (PAFC) generators. Removal of greater 60% of the sulfur in diesel fuel was demonstrated, and sorbent sulfur loadings of approximately 1 wt% were attained. Preliminary studies indicated that the sorbents are regenerable, with up to 70% of the sorbed sulfur removed during regeneration. Incorporation of this technology into a PAFC power plant should reduce the weight of the sulfur removal unit by a minimum of 25%.

Sulfur diagenesis in marine sediments

NASA Technical Reports Server (NTRS)

Goldhaber, M.

1985-01-01

Bacterial sulfate reduction occurs in all marine sediments that contain organic matter. Aqueous sulfide (HS-, H2S), one of the initial products of bacterial sulfide reduction, is extremely reactive with iron bearing minerals: sulfur is fixed into sediments as iron sulfide (first FeS and then Fe2S2). A working definition is given of sulfur diagenesis in marine sediments. Controls and consequences of sulfate reduction rates in marine sediments are examined.

Effects of acid rain and sulfur dioxide on marble dissolution

USGS Publications Warehouse

Schuster, Paul F.; Reddy, Michael M.; Sherwood, Susan I.

1994-01-01

Acid precipitation and the dry deposition of sulfur dioxide (SO2) accelerate damage to carbonate-stone monuments and building materials. This study identified and quantified environmental damage to a sample of Vermont marble during storms and their preceding dry periods. Results from field experiments indicated the deposition of SO2 gas to the stone surface during dry periods and a twofold increase in marble dissolution during coincident episodes of low rain rate and decreased rainfall pH. The study is widely applicable to the analysis of carbonate-stone damage at locations affected by acid rain and air pollution.

Particle size distributions in Arctic polar stratospheric clouds, growth and freezing of sulfuric acid droplets, and implications for cloud formation

NASA Technical Reports Server (NTRS)

Dye, James E.; Baumgardner, D.; Gandrud, B. W.; Kawa, S. R.; Kelly, K. K.; Loewenstein, M.; Ferry, G. V.; Chan, K. R.; Gary, B. L.

1992-01-01

The paper uses particle size and volume measurements obtained with the forward scattering spectrometer probe model 300 during January and February 1989 in the Airborne Arctic Stratospheric Experiment to investigate processes important in the formation and growth of polar stratospheric cloud (PSC) particles. It is suggested on the basis of comparisons of the observations with expected sulfuric acid droplet deliquescence that in the Arctic a major fraction of the sulfuric acid droplets remain liquid until temperatures at least as low as 193 K. It is proposed that homogeneous freezing of the sulfuric acid droplets might occur near 190 K and might play a role in the formation of PSCs.

[Respiratory manifestations after exposure to sulfurous anhydride in wine-cellar workers: 6 case reports].

PubMed

Testud, F; Matray, D; Lambert, R; Hillion, B; Blanchet, C; Teisseire, C; Thibaudier, J M; Raoux, C; Pacheco, Y

2000-02-01

Sulfite treatment of wine [a process exploiting the biocidal and anti-oxidant properties of sulfur dioxide (SO2)] involves the use of liquified gas, aqueous solutions or bisulfites, i.e. the salts of sulfurous acid which slowly release SO2. This procedure can result in repeated exposures of operators to significant amounts of SO2. However, risks associated with the use of SO2 are greatly under-estimated by wine producers and wine-cellar workers. We report on 6 cases of respiratory symptoms attributable to SO2 identified during a survey of wine-cellars in the French Beaujolais district. Their pathogenesis is discussed after an overview of the occupational toxicology of SO2.

New insights into sulfur amino acid function in gut health and disease

USDA-ARS?s Scientific Manuscript database

The gastrointestinal tract (GIT) is a metabolically significant site of sulfur amino acids (SAA) metabolism in the body. Aside from their role in protein synthesis, methionine and cysteine are involved in many biological functions and diseases. Methionine (MET) is an indispensable AA and is transmet...

An Aerosol Condensation Model for Sulfur Trioxide

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

Grant, K E

This document describes a model for condensation of sulfuric acid aerosol given an initial concentration and/or source of gaseous sulfur trioxide (e.g. fuming from oleum). The model includes the thermochemical effects on aerosol condensation and air parcel buoyancy. Condensation is assumed to occur heterogeneously onto a preexisting background aerosol distribution. The model development is both a revisiting of research initially presented at the Fall 2001 American Geophysical Union Meeting [1] and a further extension to provide new capabilities for current atmospheric dispersion modeling efforts [2]. Sulfuric acid is one of the most widely used of all industrial chemicals. In 1992,more » world consumption of sulfuric acid was 145 million metric tons, with 42.4 Mt (mega-tons) consumed in the United States [10]. In 2001, of 37.5 Mt consumed in the U.S., 74% went into producing phosphate fertilizers [11]. Another significant use is in mining industries. Lawuyi and Fingas [7] estimate that, in 1996, 68% of use was for fertilizers and 5.8% was for mining. They note that H{sub 2}SO{sub 4} use has been and should continue to be very stable. In the United States, the elimination of MTBE (methyl tertiary-butyl ether) and the use of ethanol for gasoline production are further increasing the demand for petroleum alkylate. Alkylate producers have a choice of either a hydrofluoric acid or sulfuric acid process. Both processes are widely used today. Concerns, however, over the safety or potential regulation of hydrofluoric acid are likely to result in most of the growth being for the sulfuric acid process, further increasing demand [11]. The implication of sulfuric acid being a pervasive industrial chemical is that transport is also pervasive. Often, this is in the form of oleum tankers, having around 30% free sulfur trioxide. Although sulfuric acid itself is not a volatile substance, fuming sulfuric acid (referred to as oleum) is [7], the volatile product being sulfur

Effect of acidic aqueous solution on chemical and physical properties of polyamide NF membranes

NASA Astrophysics Data System (ADS)

Jun, Byung-Moon; Kim, Su Hwan; Kwak, Sang Kyu; Kwon, Young-Nam

2018-06-01

This work was systematically investigated the effects of acidic aqueous solution (15 wt% sulfuric acid as model wastewater from smelting process) on the physical and chemical properties of commercially available nanofiltration (NF) polyamide membranes, using piperazine (PIP)-based NE40/70 membranes and m-phenylene diamine (MPD)-based NE90 membrane. Surface properties of the membranes were studied before and after exposure to strong acid using various analytical tools: Scanning Electron Microscopy (SEM), Attenuated Total Reflectance-Fourier Transform Infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS), contact angle analyzer, and electrophoretic light scattering spectrophotometer. The characterization and permeation results showed piperazine-based NE40/70 membranes have relatively lower acid-resistance than MPD-based NE90 membrane. Furthermore, density functional theory (DFT) calculation was also conducted to reveal the different acid-tolerances between the piperazine-based and MPD-based polyamide membranes. The easiest protonation was found to be the protonation of oxygen in piperazine-based monomer, and the N-protonation of the monomer had the lowest energy barrier in the rate determining step (RDS). The calculations were well compatible with the surface characterization results. In addition, the energy barrier in RDS is highly correlated with the twist angle (τD), which determines the delocalization of electrons between the carbonyl πCO bond and nitrogen lone pair, and the tendency of the twist angle was also maintained in longer molecules (dimer and trimer). This study clearly explained why the semi-aromatic membrane (NE40/70) is chemically less stable than the aromatic membrane (NE90) given the surface characterizations and DFT calculation results.

Graft polymerization of acrylic acid and methacrylic acid onto poly(vinylidene fluoride) powder in presence of metallic salt and sulfuric acid

NASA Astrophysics Data System (ADS)

Deng, Bo; Yu, Yang; Zhang, Bowu; Yang, Xuanxuan; Li, Linfan; Yu, Ming; Li, Jingye

2011-02-01

Poly(vinylidene fluoride) (PVDF) powder was grafted with acrylic acid (AAc) or methacrylic acid (MAA) by the pre-irradiation induced graft polymerization technique. The presence of graft chains was proven by FT-IR spectroscopy. The degree of grafting (DG) was calculated by the acid-base back titration method. The synergistic effect of acid and Mohr's salt on the grafting kinetics was examined. The results indicated that adding sulfuric acid and Mohr's salt simultaneously in AAc or MAA solutions led to a strong enhancement in the degree of grafting. The grafted PVDF powder was cast into microfiltration (MF) membranes using the phase inversion method and some properties of the obtained MF membranes were characterized.

Sulfur amino acids and alanine on pyrite (100) by X-ray photoemission spectroscopy: Surface or molecular role?

NASA Astrophysics Data System (ADS)

Sanchez-Arenillas, M.; Galvez-Martinez, S.; Mateo-Marti, E.

2017-08-01

This paper describes the first successful adsorption of the cysteine, cystine, methionine and alanine amino acids on the pyrite (100) surface under ultra-high vacuum conditions with crucial chemical adsorption parameters driving the process. We have demonstrated by X-ray photoemission spectroscopy (XPS) that the surface pretreatment annealing process on pyrite surfaces is a critical parameter driving surface reactivity. The presence of enriched monosulfide species on the pyrite (100) surface favours the amino acid NH2 chemical form, whereas a longer annealing surface pretreatment of over 3 h repairs the sulfur vacancies in the pyrite, enriching disulfide species on the pyrite surface, which promotes NH3+ adsorption due to the sulfur vacancies in the pyrite being replaced by sulfur atom dimers (S22-) on the surface. Furthermore, even if the surface chemistry (monosulfide or disulfide species enrichment) is the main factor promoting a partial conversion from NH2 to NH3+ species, the unique chemical structure of each amino acid provides a particular fingerprint in the process.

The Speciation of Sulfur in an Ocean on Europa

NASA Technical Reports Server (NTRS)

Zolotov, M. Yu.; Shock, E. L.

2002-01-01

Stability of native sulfur, iron sulfides, and aqueous sulfur compounds is evaluated at assumed P-T conditions of the Europa's ocean floor. Pyrite, gypsum, and ferric hydroxides can coexist in contact with sulfate-rich oceanic water. Additional information is contained in the original extended abstract.

Two-stage, dilute sulfuric acid hydrolysis of wood : an investigation of fundamentals

Treesearch

John F. Harris; Andrew J. Baker; Anthony H. Conner; Thomas W. Jeffries; James L. Minor; Roger C. Pettersen; Ralph W. Scott; Edward L Springer; Theodore H. Wegner; John I. Zerbe

1985-01-01

This paper presents a fundamental analysis of the processing steps in the production of methanol from southern red oak (Quercus falcata Michx.) by two-stage dilute sulfuric acid hydrolysis. Data for hemicellulose and cellulose hydrolysis are correlated using models. This information is used to develop and evaluate a process design.

The Corrosion Behavior of Ni3(Si,Nb) Alloys in Boiling 70 wt.% Sulfuric Acid

NASA Astrophysics Data System (ADS)

Hsu, Jen-Hsien; Larson, Christopher M.; Newkirk, Joseph W.; Brow, Richard K.; Zhang, San-Hong

2016-02-01

Corrosion-resistant Ni3(Si,Nb) alloys are promising materials of construction for hydrogen-production systems based on the sulfur-iodine thermochemical cycle. In this work, the corrosion rates of three different Ni3(Si,Nb) alloys were measured in boiling 70 wt.% sulfuric acid and a three-stage corrosion mechanism was identified, based on the composition and morphology of surface scale that developed. The α(Ni) + β(Ni3Si) eutectic constituent of the alloy microstructure was selectively attacked by acid and, when present, is detrimental to corrosion resistance. The G-phase (Ni16Si17Nb6) is more passive than the β-matrix and seems to contribute to a lower steady-state corrosion rate.

Sulfur amino acids are necessary for normal intestinal mucosal growth in neonatal piglets

USDA-ARS?s Scientific Manuscript database

Sulfur amino acids (SAAs) methionine and cysteine play important metabolic and functional role in human health and disease. Gastrointestinal tract is an important site of transmethylation and transsulfuration of methionine and metabolizes approx. 20% of the dietary methionine intake (Riedijk et al. ...

Thermally induced degradation of sulfur-containing aliphatic glucosinolates in broccoli sprouts (Brassica oleracea var. italica) and model systems.

PubMed

Hanschen, Franziska S; Platz, Stefanie; Mewis, Inga; Schreiner, Monika; Rohn, Sascha; Kroh, Lothar W

2012-03-07

Processing reduces the glucosinolate (GSL) content of plant food, among other aspects due to thermally induced degradation. Since there is little information about the thermal stability of GSL and formation of corresponding breakdown products, the thermally induced degradation of sulfur-containing aliphatic GSL was studied in broccoli sprouts and with isolated GSL in dry medium at different temperatures as well as in aqueous medium at different pH values. Desulfo-GSL have been analyzed with HPLC-DAD, while breakdown products were estimated using GC-FID. Whereas in the broccoli sprouts structural differences of the GSL with regard to thermal stability exist, the various isolated sulfur-containing aliphatic GSL degraded nearly equally and were in general more stable. In broccoli sprouts, methylsulfanylalkyl GSL were more susceptible to degradation at high temperatures, whereas methylsulfinylalkyl GSL were revealed to be more affected in aqueous medium under alkaline conditions. Besides small amounts of isothiocyanates, the main thermally induced breakdown products of sulfur-containing aliphatic GSL were nitriles. Although they were most rapidly formed at comparatively high temperatures under dry heat conditions, their highest concentrations were found after cooking in acidic medium, conditions being typical for domestic processing.

Sulfuric Acid Monohydrate: Formation and Heterogeneous Chemistry in the Stratosphere

NASA Technical Reports Server (NTRS)

Zhang, Renyi; Leu, Ming-Taun; Keyser, Leon F.

1995-01-01

We have investigated some thermodynamic properties (i.e., freezing/melting points) and heterogeneous chemistry of sulfuric acid monohydrate (SAM, H2SO4.H2O), using a fast flow reactor coupled to a quadrupole mass spectrometer. The freezing point observations of thin liquid sulfuric acid films show that for acid contents between 75 and 85 wt % the monohydrate crystallizes readily at temperatures between 220 and 240 K on a glass substrate. Once formed, SAM can be thermodynamically stable in the H2O partial pressure range of (1-4) x 10(exp -4) torr and in the temperature range of 220-240 K. For a constant H2O partial pressure, lowering the temperature causes SAM to melt when the temperature and water partial pressure conditions are out of its stability regime. The reaction probability measurements indicate that the hydrolysis of N2O5 is significantly suppressed owing to the formation of crystalline SAM: The reaction probability on water-rich SAM (with higher relative humidity, or RH) is of the order of 10(exp -3) at 210 K and decreases by more than an order of magnitude for the acid-rich form (with lower RH). The hydrolysis rate of ClONO2 on water-rich SAM is even smaller, of the order of 10(exp -4) at 195 K. These reported values on crystalline SAM are much smaller than those on liquid solutions. No enhancement of these reactions is observed in the presence of HCl vapor at the stratospheric concentrations. In addition, Brunauer, Emmett, and Teller analysis of gas adsorption isotherms and photomicrography have been performed to characterize the surface roughness and porosities of the SAM substrate. The results suggest the possible formation of SAM in some regions of the middle- or low-latitude stratosphere and, consequently, much slower heterogeneous reactions on the frozen aerosols.

Sulfur Cycle

NASA Technical Reports Server (NTRS)

Hariss, R.; Niki, H.

1985-01-01

Among the general categories of tropospheric sulfur sources, anthropogenic sources have been quantified the most accurately. Research on fluxes of sulfur compounds from volcanic sources is now in progress. Natural sources of reduced sulfur compounds are highly variable in both space and time. Variables, such as soil temperature, hydrology (tidal and water table), and organic flux into the soil, all interact to determine microbial production and subsequent emissions of reduced sulfur compounds from anaerobic soils and sediments. Available information on sources of COS, CS2, DMS, and H2S to the troposphere in the following paragraphs are summarized; these are the major biogenic sulfur species with a clearly identified role in tropospheric chemistry. The oxidation of SO2 to H2SO4 can often have a significant impact on the acidity of precipitation. A schematic representation of some important transformations and sinks for selected sulfur species is illustrated.

Extraction of steroidal glucosiduronic acids from aqueous solutions by anionic liquid ion-exchangers

PubMed Central

Mattox, Vernon R.; Litwiller, Robert D.; Goodrich, June E.

1972-01-01

A pilot study on the extraction of three steroidal glucosiduronic acids from water into organic solutions of liquid ion-exchangers is reported. A single extraction of a 0.5mm aqueous solution of either 11-deoxycorticosterone 21-glucosiduronic acid or cortisone 21-glucosiduronic acid with 0.1m-tetraheptylammonium chloride in chloroform took more than 99% of the conjugate into the organic phase; under the same conditions, the very polar conjugate, β-cortol 3-glucosiduronic acid, was extracted to the extent of 43%. The presence of a small amount of chloride, acetate, or sulphate ion in the aqueous phase inhibited extraction, but making the aqueous phase 4.0m with ammonium sulphate promoted extraction strongly. An increase in the concentration of ion-exchanger in the organic phase also promoted extraction. The amount of cortisone 21-glucosiduronic acid extracted by tetraheptylammonium chloride over the pH range of 3.9 to 10.7 was essentially constant. Chloroform solutions of a tertiary, a secondary, or a primary amine hydrochloride also will extract cortisone 21-glucosiduronic acid from water. The various liquid ion exchangers will extract steroidal glucosiduronic acid methyl esters from water into chloroform, although less completely than the corresponding free acids. The extraction of the glucosiduronic acids from water by tetraheptylammonium chloride occurs by an ion-exchange process; extraction of the esters does not involve ion exchange. PMID:5075264

PRODUCTION OF TRIFLUOROACETIC ACID COMPOUNDS

DOEpatents

Haworth, W.N.; Stacey, M.

1949-08-30

A process is described for the preparation of trifluoroacetic acid. Acetone vapor diluted wlth nitrogen and fluorine also diluted with nltrogen are fed separately at a temperature of about 210 deg C into a reaction vessel containing a catalyst mass selected from-the group consisting of silver and gold. The temperature in the reaction vessel is maintained in the range of 200 deg to 250 deg C. The reaction product, trifluoroacetyl fluoride, is absorbed in aqueous alkali solution. Trifluoroacetic acid is recovered from the solution by acidification wlth an acid such as sulfuric followed by steam distillation.

The adsorption of gold, palladium and platinum from acidic chloride solutions on mesoporous carbons.

DOE PAGES

Zalupski, Peter R.; McDowell, Rocklan; Dutech, Guy

2014-08-05

Studies on the adsorption characteristics of gold, palladium and platinum on mesoporous carbon (CMK-3) and sulfur-impregnated mesoporous carbon (CMK-3/S) evaluated the benefits/drawbacks of the presence of a layer of elemental sulfur inside mesoporous carbon structures. Adsorption isotherms collected for Au(III), Pd(II) and Pt(IV) on those materials suggest that sulfur does enhance the adsorption of those metal ions in mildly acidic environment (pH 3). The isotherms collected in 1 M HCl show that the benefit of sulfur disappears due to the competing influence of large concentration of hydrogen ions on the ion-exchanging mechanism of metal ions sorption on mesoporous carbon surfaces.more » The collected acid dependencies illustrate similar adsorption characteristics for CMK-3 and CMK-3/S in 1-5 M HCl concentration range. Sorption of metal ions from diluted aqueous acidic mixtures of actual leached electronic waste demonstrated the feasibility of recovery of gold from such liquors.« less

STREAMWATER ACID-BASED CHEMISTRY AND CRITICAL LOADS OF ATMOSPHERIC SULFUR DEPOSITION IN SHENANDOAH NATIONAL PARK, VIRGINIA

EPA Science Inventory

A modeling study was conducted to evaluate the acid-base chemistry of streams within Shenandoah National Park, Virginia and to project future responses to sulfur (S) and nitrogen (N) atmospheric emissions controls. Many of the major stream systems in the Park have acid neutraliz...

Molecular dynamics simulation studies of the interactions between ionic liquids and amino acids in aqueous solution.

PubMed

Tomé, Luciana I N; Jorge, Miguel; Gomes, José R B; Coutinho, João A P

2012-02-16

Although the understanding of the influence of ionic liquids (ILs) on the solubility behavior of biomolecules in aqueous solutions is relevant for the design and optimization of novel biotechnological processes, the underlying molecular-level mechanisms are not yet consensual or clearly elucidated. In order to contribute to the understanding of the molecular interactions established between amino acids and ILs in aqueous media, classical molecular dynamics (MD) simulations were performed for aqueous solutions of five amino acids with different structural characteristics (glycine, alanine, valine, isoleucine, and glutamic acid) in the presence of 1-butyl-3-methylimidazolium bis(trifluoromethyl)sulfonyl imide. The results from MD simulations enable to relate the properties of the amino acids, namely their hydrophobicity, to the type and strength of their interactions with ILs in aqueous solutions and provide an explanation for the direction and magnitude of the solubility phenomena observed in [IL + amino acid + water] systems by a mechanism governed by a balance between competitive interactions of the IL cation, IL anion, and water with the amino acids.

Radical-driven carbonyl-to-acid conversion and acid degradation in tropospheric aqueous systems studied by CAPRAM

NASA Astrophysics Data System (ADS)

Tilgner, A.; Herrmann, H.

2010-12-01

Model studies on the aqueous phase radical-driven processing of carbonyl compounds and acids in clouds and deliquescent particles were performed. The model exposed that aqueous radical conversions of carbonyl compounds and its oxidation products can contribute potentially to the formation of functionalised organic acids. The main identified C 2-C 4 organic gas phase precursors are ethylene glycol, glycolaldehyde, glyoxal, methylglyoxal and 1,4-butenedial. The aqueous phase is shown to contribute significantly with about 93%/63%, 47%/8%, 31%/4%, 7%/4%, 36%/8% to the multiphase oxidative fate of these compounds under remote/urban conditions. Interestingly, the studies revealed that aqueous chemical processing is not only limited to in-cloud conditions but also proceeds in deliquescent particle phase with significant fluxes. Oxalic acid is shown to be formed preferably in deliquescent particles subsequent to the in-cloud oxidations. Mean aqueous phase oxalate formation fluxes of about 12, 42 and 0.4 ng m -3 h -1 in the remote, urban and maritime scenario, respectively. Additionally, the turnovers of the oxidation of organics such as methylglyoxal by NO 3 radical reactions are identified to be competitive to their OH pendants. At the current state of CAPRAM, mean C 2-C 4 in-cloud oxidation fluxes of about 0.12 and 0.5 μg m -3 h -1 are modelled under the idealised remote and urban cloud conditions. Finally, turnovers from radical oxidations were compared with those of thermal reactions. It is demonstrated that, based on the sparse kinetic data available organic accretion reaction might be of interest in just a few cases for cloud droplets and aqueous particles but generally do not reach the oxidative conversion rates of the main radical oxidants OH and NO 3. Interestingly, oxidation reactions of H 2O 2 are shown to be competitive to the OH radical conversions in cases when H 2O 2 is not readily used up by the S(IV) oxidation.

INTERACTION OF AQUEOUS SOLUTIONS OF CHLORINE WITH MALIC ACID, TARTARIC ACID, AND VARIOUS FRUIT JUICES, A SOURCE OF MUTAGENS

EPA Science Inventory

The interactions of aqueous solutions of chlorine with some fruit acids (citric acid, DL-malic acid, and L-tartaric acid) at different pH values were studied. iethyl ether extraction followed by GC/MS analysis indicated that a number of mutagens (certain chlorinated propanones an...

Structural analysis and taste evaluation of γ-glutamyl peptides comprising sulfur-containing amino acids.

PubMed

Amino, Yusuke; Wakabayashi, Hidehiko; Akashi, Satoko; Ishiwatari, Yutaka

2018-03-01

The structures, flavor-modifying effects, and CaSR activities of γ-glutamyl peptides comprising sulfur-containing amino acids were investigated. The chemical structures, including the linkage mode of the N-terminal glutamic acid, of γ-L-glutamyl-S-(2-propenyl)-L-cysteine (γ-L-glutamyl-S-allyl-L-cysteine) and its sulfoxide isolated from garlic were established by comparing their NMR spectra with those of authentic peptides prepared using chemical methods. Mass spectrometric analysis also enabled determination of the linkage modes in the glutamyl dipeptides by their characteristic fragmentation. In sensory evaluation, these peptides exhibited flavor-modifying effects (continuity) in umami solutions less pronounced but similar to that of glutathione. Furthermore, the peptides exhibited intrinsic flavor due to the sulfur-containing structure, which may be partially responsible for their flavor-modifying effects. In CaSR assays, γ-L-glutamyl-S-methyl-L-cysteinylglycine was most active, which indicates that the presence of a medium-sized aliphatic substituent at the second amino acid residue in γ-glutamyl peptides enhances CaSR activity.

Production of fuel ethanol from bamboo by concentrated sulfuric acid hydrolysis followed by continuous ethanol fermentation.

PubMed

Sun, Zhao-Yong; Tang, Yue-Qin; Iwanaga, Tomohiro; Sho, Tomohiro; Kida, Kenji

2011-12-01

An efficient process for the production of fuel ethanol from bamboo that consisted of hydrolysis with concentrated sulfuric acid, removal of color compounds, separation of acid and sugar, hydrolysis of oligosaccharides and subsequent continuous ethanol fermentation was developed. The highest sugar recovery efficiency was 81.6% when concentrated sulfuric acid hydrolysis was carried out under the optimum conditions. Continuous separation of acid from the saccharified liquid after removal of color compounds with activated carbon was conducted using an improved simulated moving bed (ISMB) system, and 98.4% of sugar and 90.5% of acid were recovered. After oligosaccharide hydrolysis and pH adjustment, the unsterilized saccharified liquid was subjected to continuous ethanol fermentation using Saccharomycescerevisiae strain KF-7. The ethanol concentration, the fermentation yield based on glucose and the ethanol productivity were approximately 27.2 g/l, 92.0% and 8.2 g/l/h, respectively. These results suggest that the process is effective for production of fuel ethanol from bamboo. Copyright © 2011 Elsevier Ltd. All rights reserved.

40 CFR 180.1019 - Sulfuric acid; exemption from the requirement of a tolerance.

Code of Federal Regulations, 2011 CFR

2011-07-01

... AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD... good agricultural practice when used as a herbicide in the production of garlic and onions, and as a... from the use of sulfuric acid as an inert ingredient in a pesticide product used in irrigation...

Interaction of Ethyl Alcohol Vapor with Sulfuric Acid Solutions

NASA Technical Reports Server (NTRS)

Leu, Ming-Taun

2006-01-01

We investigated the uptake of ethyl alcohol (ethanol) vapor by sulfuric acid solutions over the range approx.40 to approx.80 wt % H2SO4 and temperatures of 193-273 K. Laboratory studies used a fast flow-tube reactor coupled to an electron-impact ionization mass spectrometer for detection of ethanol and reaction products. The uptake coefficients ((gamma)) were measured and found to vary from 0.019 to 0.072, depending upon the acid composition and temperature. At concentrations greater than approx.70 wt % and in dilute solutions colder than 220 K, the values approached approx.0.07. We also determined the effective solubility constant of ethanol in approx.40 wt % H2SO4 in the temperature range 203-223 K. The potential implications to the budget of ethanol in the global troposphere are briefly discussed.

Smectite Formation in Acid Sulfate Environments on Mars

NASA Technical Reports Server (NTRS)

Peretyazhko, T. S.; Niles, P. B.; Sutter, B.; Clark, J. V.; Morris, R. V.; Ming, D. W.

2017-01-01

Phyllosilicates of the smectite group detected in Noachian and early Hesperian terrains on Mars were hypothesized to form under aqueous conditions that were globally neutral to alkaline. These pH conditions and the presence of a CO2-rich atmosphere should have been favorable for the formation of large carbonate deposits. However, large-scale carbonate deposits have not been detected on Mars. We hypothesized that smectite deposits are consistent with perhaps widespread acidic aqueous conditions that prevented carbonate precipitation. The objective of our work was to investigate smectite formation under acid sulfate conditions in order to provide insight into the possible geochemical conditions required for smectite formation on Mars. Hydrothermal batch incubation experiments were performed with Mars-analogue, glass-rich, basalt simulant in the presence of sulfuric acid of variable concentration.

[Application of the vanillin sulfuric acid colorimetry-ultraviolet spectrometry on quality evaluation of Panax notoginseng].

PubMed

Ding, Yong-Li; Wang, Yuan-Zhong; Zhang, Ji; Zhang, Qing-Zhi; Zhang, Jin-Yu; Jin, Hang

2013-02-01

In this study, Panax notoginseng samples were extracted by chloroform, ethanol and water, or by those extracted solution with 5% vanillin sulfuric acid to establish two kinds of UV fingerprint of P. notoginseng which were compared by applying the common and variation peak ratio dual index sequence analysis method and SIMCA software qualitative analysis. The results indicated that the optimization extraction time of P. notoginseng samples was 20 min with chloroform, ethanol and water extraction, but the fingerprint differed significantly after add vanillin sulfuric acid. The common peak ratios of UV fingerprint of P. notoginseng were scattered. The minimum was 25% (Y5-Y8), while the maximum was 84.38% (Y11-Y13, Y20-Y21). The maximum variation peak ratio was 177.78% (Y8-Y5), meanwhile, the variation peak ratios of several samples were more than 100%. However, the common peak ratios of UV fingerprint of P. notoginseng with vanillin sulfuric acid were concentrated (distributed in the range of 50%-70%): the minimum was 42.86%(Y1-Y19), whereas the maximum was 79.55% (Y22-Y23); the range of the variation peak ratios was also smaller with the ranges of 20%-50% in general. The result of the dual index sequence analysis was agreement with the fingerprint implied. The similarity of the UV fingerprint of the extracts of P. notoginseng after adding vanillin sulfuric acid was greater than before. Both the ages and origin was related with the difference of UV fingerprint. The similarity of the two samples with same age was more significant than those with different ages. The similarity and difference between samples was no correlation with the distance of geographic space, the near origin samples maybe have a significant similarity or difference. This method appears as good alternative for evaluate quality of the P. notoginseng and can distinguish at least two samples quantitatively, duo to it reaches the limitation of the multiple methods which only could be used to indistinctly

Solution blow spun nanocomposites of poly(lactic acid)/cellulose nanocrystals from Eucalyptus kraft pulp

USDA-ARS?s Scientific Manuscript database

Cellulose nanocrystals (CNCs) were extracted from Eucalyptus kraft pulp by sulfuric acid hydrolysis, and esterified with maleic anhydride (CNCMA). The incorporation of sulfate ester groups on the cellulose surface resulted in higher stability of the nanoparticles in aqueous suspensions and lower the...

Reactions of SIV species with organic compounds: formation mechanisms of organo-sulfur derivatives in atmospheric aerosols

NASA Astrophysics Data System (ADS)

Passananti, Monica; Shang, Jing; Dupart, Yoan; Perrier, Sébastien; George, Christian

2015-04-01

Secondary organic aerosol (SOA) have an important impact on climate, air quality and human health. However the chemical reactions involved in their formation and growth are not fully understood or well-constrained in climate models. It is well known that inorganic sulfur (mainly in oxidation states (+IV) and (+VI)) plays a key role in aerosol formation, for instance sulfuric acid is known to be a good nucleating gas. In addition, acid-catalyzed heterogeneous reactions of organic compounds has shown to produce new particles, with a clear enhancement in the presence of ozone (Iinuma 2013). Organosulfates have been detected in tropospheric particles and aqueous phases, which suggests they are products of secondary organic aerosol formation process (Tolocka 2012). Originally, the production of organosulfates was explained by the esterification reaction of alcohols, but this reaction in atmosphere is kinetically negligible. Other formation pathways have been suggested such as hydrolysis of peroxides and reaction of organic matter with sulfite and sulfate radical anions (SO3-, SO4-) (Nozière 2010), but it remains unclear if these can completely explain atmospheric organo-sulfur aerosol loading. To better understand the formation of organo-sulfur compounds, we started to investigate the reactivity of SIV species (SO2 and SO32-) with respect to specific functional groups (organic acids and double bonds) on atmospherically relevant carboxylic acids and alkenes. The experiments were carried out in the homogeneous aqueous phase and at the solid-gas interface. A custom built coated-wall flow tube reactor was developed to control relativity humidity, SO2 concentration, temperature and gas flow rate. Homogeneous and heterogeneous reaction kinetics were measured and resulting products were identified using liquid chromatography coupled with an orbitrap mass spectrometer (LC-HR-MS). The experiments were performed with and without the presence of ozone in order to evaluate any

Quantitative comparison of caffeoylquinic acids and flavonoids in Chrysanthemum morifolium flowers and their sulfur-fumigated products by three-channel liquid chromatography with electrochemical detection.

PubMed

Chen, Liangmian; Kotani, Akira; Kusu, Fumiyo; Wang, Zhimin; Zhu, Jingjing; Hakamata, Hideki

2015-01-01

For the determination of seven caffeoylquinic acids [neochlorogenic acid (NcA), cryptochlorogenic acid (CcA), chlorogenic acid (CA), caffeic acid (CfA), isochlorogenic acid A (Ic A), isochlorogenic acid B (Ic B), isochlorogenic acid C (Ic C)] and two flavonoids [luteolin 7-O-glucoside (LtG) and luteolin (Lt)], a three-channel liquid chromatography with electrochemical detection (LC-3ECD) method was established. Chromatographic peak heights were proportional to each concentration, ranging from 2.5 to 100 ng/mL for NcA, CA, CcA, and CfA, and ranging from 2.5 to 250 ng/mL for LtG, Ic B, Ic A, Ic C, and Lt, respectively. The present LC-3ECD method was applied to the quantitative analysis of caffeoylquinic acids and flavonoids in four cultivars of Chrysanthemum morifolium flowers and their sulfur-fumigated products. It was found that 60% of LtG and more than 47% of caffeoylquinic acids were lost during the sulfur fumigation processing. Sulfur fumigation showed a destructive effect on the C. morifolium flowers. In addition, principle component analyses (PCA) were performed using the results of the quantitative analysis of caffeoylquinic acids and flavonoids to compare the "sameness" and "differences" of these analytes in C. morifolium flowers and the sulfur-fumigated products. PCA score plots showed that the four cultivars of C. morifolium flowers were clearly classified into four groups, and that significant differences were also found between the non-fumigated C. morifolium flowers and the sulfur-fumigated products. Therefore, it was demonstrated that the present LC-3ECD method coupled with PCA is applicable to the variation analysis of different C. morifolium flower samples.

Identification of sulfur sources and isotopic equilibria in submarine hot-springs using multiple sulfur isotopes

NASA Astrophysics Data System (ADS)

McDermott, Jill M.; Ono, Shuhei; Tivey, Margaret K.; Seewald, Jeffrey S.; Shanks, Wayne C.; Solow, Andrew R.

2015-07-01

Multiple sulfur isotopes were measured in metal sulfide deposits, elemental sulfur, and aqueous hydrogen sulfide to constrain sulfur sources and the isotopic systematics of precipitation in seafloor hydrothermal vents. Areas studied include the Eastern Manus Basin and Lau Basin back-arc spreading centers and the unsedimented basalt-hosted Southern East Pacific Rise (SEPR) and sediment-hosted Guaymas Basin mid-ocean ridge spreading centers. Chalcopyrite and dissolved hydrogen sulfide (H2S) δ34S values range from -5.5‰ to +5.6‰ in Manus Basin samples, +2.4‰ to +6.1‰ in Lau Basin samples, and +3.7‰ to +5.7‰ in SEPR samples. Values of δ34S for cubic cubanite and H2S range from -1.4‰ to +4.7‰ in Guaymas Basin samples. Multiple sulfur isotope systematics in fluid-mineral pairs from the SEPR and Lau Basin show that crustal host rock and thermochemical reduction of seawater-derived dissolved sulfate (SO4) are the primary sources of sulfur in mid-ocean ridge and some back-arc systems. At PACMANUS and SuSu Knolls hydrothermal systems in the Eastern Manus Basin, a significant contribution of sulfur is derived from disproportionation of magmatic sulfur dioxide (SO2), while the remaining sulfur is derived from crustal host rocks and SO4 reduction. At the sedimented Guaymas Basin hydrothermal system, sulfur sources include crustal host rock, reduced seawater SO4, and biogenic sulfide. Vent fluid flow through fresher, less-mature sediment supplies an increased quantity of reactant organic compounds that may reduce 34S-enriched SO4, while fluid interaction with more highly-altered sediments results in H2S characterized by a small, but isotopically-significant input of 34S-depleted biogenic sulfides. Near-zero Δ33S values in all samples implicate the abiotic processes of SO4 reduction and leaching of host rock as the major contributors to sulfur content at a high temperature unsedimented mid-ocean ridge and at a back-arc system. Δ33S values indicate that SO2

Fabrication of Self-Ordered Nanoporous Alumina with 69-115 nm Interpore Distances in Sulfuric/Oxalic Acid Mixtures by Hard Anodization

NASA Astrophysics Data System (ADS)

Almasi Kashi, Mohammad; Ramazani, Abdolali; Mayamai, Yashar; Noormohammadi, Mohammad

2010-01-01

Well-ordered nanoporous arrays have been obtained using hard anodization of aluminium in oxalic/sulfuric mixture. Various ordered nanoporous alumina films with pore intervals from 69 to 115 nm were fabricated on aluminum by high current anodization approach with various sulfuric concentrations in the oxalic/sulfuric mixture electrolyte under 36-60 V. The sulfuric acid concentration was changed from 0.06 to 0.2 M. Different configurations of the current-time curve are seen to influence the self-ordering of the nanohole arrays. A current density-time curve with exponential oscillating decay configuration is seen to damage the self-ordered array of the nanopores while those with exponential decay under certain conditions cause ordered nanopore arrays. For each electrolyte mixture, the interpore distance was dependent upon the anodization voltages with proportionality constants of almost 2 nm V-1. The porosity of the samples (about 3.5%) follows the porosity rule of HA. Final anodization and increasing voltage rate (rin) as a function of sulfuric acid concentration are the main sources to influence the self-ordering of the samples.

Molecular understanding of atmospheric particle formation from sulfuric acid and large oxidized organic molecules

PubMed Central

Schobesberger, Siegfried; Junninen, Heikki; Bianchi, Federico; Lönn, Gustaf; Ehn, Mikael; Lehtipalo, Katrianne; Dommen, Josef; Ehrhart, Sebastian; Ortega, Ismael K.; Franchin, Alessandro; Nieminen, Tuomo; Riccobono, Francesco; Hutterli, Manuel; Duplissy, Jonathan; Almeida, João; Amorim, Antonio; Breitenlechner, Martin; Downard, Andrew J.; Dunne, Eimear M.; Flagan, Richard C.; Kajos, Maija; Keskinen, Helmi; Kirkby, Jasper; Kupc, Agnieszka; Kürten, Andreas; Kurtén, Theo; Laaksonen, Ari; Mathot, Serge; Onnela, Antti; Praplan, Arnaud P.; Rondo, Linda; Santos, Filipe D.; Schallhart, Simon; Schnitzhofer, Ralf; Sipilä, Mikko; Tomé, António; Tsagkogeorgas, Georgios; Vehkamäki, Hanna; Wimmer, Daniela; Baltensperger, Urs; Carslaw, Kenneth S.; Curtius, Joachim; Hansel, Armin; Petäjä, Tuukka; Kulmala, Markku; Donahue, Neil M.; Worsnop, Douglas R.

2013-01-01

Atmospheric aerosols formed by nucleation of vapors affect radiative forcing and therefore climate. However, the underlying mechanisms of nucleation remain unclear, particularly the involvement of organic compounds. Here, we present high-resolution mass spectra of ion clusters observed during new particle formation experiments performed at the Cosmics Leaving Outdoor Droplets chamber at the European Organization for Nuclear Research. The experiments involved sulfuric acid vapor and different stabilizing species, including ammonia and dimethylamine, as well as oxidation products of pinanediol, a surrogate for organic vapors formed from monoterpenes. A striking resemblance is revealed between the mass spectra from the chamber experiments with oxidized organics and ambient data obtained during new particle formation events at the Hyytiälä boreal forest research station. We observe that large oxidized organic compounds, arising from the oxidation of monoterpenes, cluster directly with single sulfuric acid molecules and then form growing clusters of one to three sulfuric acid molecules plus one to four oxidized organics. Most of these organic compounds retain 10 carbon atoms, and some of them are remarkably highly oxidized (oxygen-to-carbon ratios up to 1.2). The average degree of oxygenation of the organic compounds decreases while the clusters are growing. Our measurements therefore connect oxidized organics directly, and in detail, with the very first steps of new particle formation and their growth between 1 and 2 nm in a controlled environment. Thus, they confirm that oxidized organics are involved in both the formation and growth of particles under ambient conditions. PMID:24101502

Mechanisms leading to oligomers and SOA through aqueous photooxidation: insights from OH radical oxidation of acetic acid and methylglyoxal

NASA Astrophysics Data System (ADS)

Tan, Y.; Lim, Y. B.; Altieri, K. E.; Seitzinger, S. P.; Turpin, B. J.

2012-01-01

Previous experiments have demonstrated that the aqueous OH radical oxidation of methylglyoxal produces low volatility products including pyruvate, oxalate and oligomers. These products are found predominantly in the particle phase in the atmosphere, suggesting that methylglyoxal is a precursor of secondary organic aerosol (SOA). Acetic acid plays a central role in the aqueous oxidation of methylglyoxal and it is a ubiquitous product of gas phase photochemistry, making it a potential "aqueous" SOA precursor in its own right. However, the fate of acetic acid upon aqueous-phase oxidation is not well understood. In this research, acetic acid (20 μM-10 mM) was oxidized by OH radicals, and pyruvic acid and methylglyoxal experimental samples were analyzed using new analytical methods, in order to better understand the formation of SOA from acetic acid and methylglyoxal. Glyoxylic, glycolic, and oxalic acids formed from acetic acid and OH radicals. In contrast to the aqueous OH radical oxidation of methylglyoxal, the aqueous OH radical oxidation of acetic acid did not produce succinic acid and oligomers. This suggests that the methylgloxal-derived oligomers do not form through the acid catalyzed esterification pathway proposed previously. Using results from these experiments, radical mechanisms responsible for oligomer formation from methylglyoxal oxidation in clouds and wet aerosols are proposed. The importance of acetic acid/acetate as an SOA precursor is also discussed. We hypothesize that this and similar chemistry is central to the daytime formation of oligomers in wet aerosols.

40 CFR 721.9220 - Reaction products of secondary alkyl amines with a substituted benzenesulfonic acid and sulfuric...

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Reaction products of secondary alkyl... Reaction products of secondary alkyl amines with a substituted benzenesulfonic acid and sulfuric acid... substances identified generically as reaction products of secondary alkyl amines with a substituted...

40 CFR 721.9220 - Reaction products of secondary alkyl amines with a substituted benzenesulfonic acid and sulfuric...

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Reaction products of secondary alkyl... Reaction products of secondary alkyl amines with a substituted benzenesulfonic acid and sulfuric acid... substances identified generically as reaction products of secondary alkyl amines with a substituted...

Response of DOC in acid-sensitive Maine lakes to decreasing sulfur deposition (1993 - 2009)

EPA Science Inventory

In response to the Clean Air Act Amendments of 1990, sulfur deposition has decreased across the northeastern United States. As a result, sulfate concentrations in lakes and streams have also decreased and many surface waters have become less acidic. Over the same time period, th...

The IUPAC aqueous and non-aqueous experimental pKa data repositories of organic acids and bases.

PubMed

Slater, Anthony Michael

2014-10-01

Accurate and well-curated experimental pKa data of organic acids and bases in both aqueous and non-aqueous media are invaluable in many areas of chemical research, including pharmaceutical, agrochemical, specialty chemical and property prediction research. In pharmaceutical research, pKa data are relevant in ligand design, protein binding, absorption, distribution, metabolism, elimination as well as solubility and dissolution rate. The pKa data compilations of the International Union of Pure and Applied Chemistry, originally in book form, have been carefully converted into computer-readable form, with value being added in the process, in the form of ionisation assignments and tautomer enumeration. These compilations offer a broad range of chemistry in both aqueous and non-aqueous media and the experimental conditions and original reference for all pKa determinations are supplied. The statistics for these compilations are presented and the utility of the computer-readable form of these compilations is examined in comparison to other pKa compilations. Finally, information is provided about how to access these databases.

The IUPAC aqueous and non-aqueous experimental pKa data repositories of organic acids and bases

NASA Astrophysics Data System (ADS)

Slater, Anthony Michael

2014-10-01

Accurate and well-curated experimental pKa data of organic acids and bases in both aqueous and non-aqueous media are invaluable in many areas of chemical research, including pharmaceutical, agrochemical, specialty chemical and property prediction research. In pharmaceutical research, pKa data are relevant in ligand design, protein binding, absorption, distribution, metabolism, elimination as well as solubility and dissolution rate. The pKa data compilations of the International Union of Pure and Applied Chemistry, originally in book form, have been carefully converted into computer-readable form, with value being added in the process, in the form of ionisation assignments and tautomer enumeration. These compilations offer a broad range of chemistry in both aqueous and non-aqueous media and the experimental conditions and original reference for all pKa determinations are supplied. The statistics for these compilations are presented and the utility of the computer-readable form of these compilations is examined in comparison to other pKa compilations. Finally, information is provided about how to access these databases.

Improved Synthesis of 5-Substituted 1H-Tetrazoles via the [3+2] Cycloaddition of Nitriles and Sodium Azide Catalyzed by Silica Sulfuric Acid

PubMed Central

Du, Zhenting; Si, Changmei; Li, Youqiang; Wang, Yin; Lu, Jing

2012-01-01

A silica supported sulfuric acid catalyzed [3+2] cycloaddition of nitriles and sodium azide to form 5-substituted 1H-tetrazoles is described. The protocol can provide a series of 5-substituted 1H-tetrazoles using silica sulfuric acid from nitriles and sodium azide in DMF in 72%–95% yield. PMID:22606004

Solubility of HOBr in Acidic Solution and Implications for Liberation of Halogens Via Aerosol Processing

NASA Technical Reports Server (NTRS)

Iraci, Laura T.; Michelsen, R. R.; Rammer, T. A.; Ashbourn, S. F. M.

2004-01-01

Halogen species are known to catalytically destroy ozone in several regions of the atmosphere. In addition to direct catalytic losses, bromine compounds can indirectly enhance ozone loss through coupling to other radical families. Hypobromous acid (HOBr) is a key species in the linkage of BrOx to ClOx and HOx. The aqueous- phase coupling reaction HOBr + HCI (right arrow) BrCl + H2O may provide a pathway for chlorine activation on sulfate aerosols at temperatures warmer than those required for polar stratospheric cloud formation. We have measured t h e solubility of HOBr in 45 - 70 wt% sulfuric acid solutions. Over the temperature range 201 - 252 K, HOBr is quite soluble in sulfuric acid, H* = 10(exp 4) - 10(exp 7) mol dm(exp -3) atm(exp -1). The expected inverse dependence of H* on temperature was observed, but only a weak dependence on acidity was found. The solubility of HOBr is comparable to that of HBr, indicating that equilibrium concentrations of HOBr could equal or exceed those of HBr in upper tropospheric and lower stratospheric aerosols. Despite the high solubility of HOBr, aerosol volumes are not large enough to sequester a significant fraction of inorganic bromine from the gas phase. Our measurements of HOBr uptake in aqueous sulfuric acid in the presence of other brominated gases show the evolution of gaseous products including Br2O and Br2.

Extraction of mercury(II) with sulfurized jojoba oil

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

Wisniak, J.; Schorr, G.; Zacovsky, D.

1990-09-01

Sulfurized jojoba oil containing 12% by weight S has been tested as an extractant for Hg(II) from aqueous solutions. This paper reports on experiments performed with the extractant dissolved in a solvent (liquid--liquid extraction) or adsorbed in an appropriate resin matrix (solid--liquid extraction). The extraction characteristics of both systems have been measured and show that sulfurized jojoba oil exhibits very good possibilities as an extractant. The performance of several resins treated with sulfurized jojoba oil for adsorbing mercury(II) was studied. The morphology of the different resins was examined by using scanning electron microscopy. The sulfurized oil is attached to themore » resin sites through the sulfur atoms; it is estimated that there are about 2 mol of S active sites per kilogram of resin.« less

A computational fluid dynamics approach to nucleation in the water-sulfuric acid system.

PubMed

Herrmann, E; Brus, D; Hyvärinen, A-P; Stratmann, F; Wilck, M; Lihavainen, H; Kulmala, M

2010-08-12

This study presents a computational fluid dynamics modeling approach to investigate the nucleation in the water-sulfuric acid system in a flow tube. On the basis of an existing experimental setup (Brus, D.; Hyvärinen, A.-P.; Viisanen, Y.; Kulmala, M.; Lihavainen, H. Atmos. Chem. Phys. 2010, 10, 2631-2641), we first establish the effect of convection on the flow profile. We then proceed to simulate nucleation for relative humidities of 10, 30, and 50% and for sulfuric acid concentration between 10(9) to 3 x 10(10) cm(-3). We describe the nucleation zone in detail and determine how flow rate and relative humidity affect its characteristics. Experimental nucleation rates are compared to rates gained from classical binary and kinetic nucleation theory as well as cluster activation theory. For low RH values, kinetic theory yields the best agreement with experimental results while binary nucleation best reproduces the experimental nucleation behavior at 50% relative humidity. Particle growth is modeled for an example case at 50% relative humidity. The final simulated diameter is very close to the experimental result.

Lead-Free Sn-Ce-O Composite Coating on Cu Produced by Pulse Electrodeposition from an Aqueous Acidic Sulfate Electrolyte

NASA Astrophysics Data System (ADS)

Sharma, Ashutosh; Das, Karabi; Das, Siddhartha

2017-10-01

Pulse-electrodeposited Sn-Ce-O composite solder coatings were synthesized on a Cu substrate from an aqueous acidic solution containing stannous sulfate (SnSO4·3H2O), sulfuric acid (H2SO4), and Triton X-100 as an additive. The codeposition was achieved by adding nano-cerium oxide powder in varying concentrations from 5 g/L to 20 g/L into the electrolytic bath. Microstructural characterization was carried out using x-ray diffraction (XRD), scanning electron microscopy, and transmission electron microscopy. The XRD analysis showed that the deposits consist mainly of tetragonal β (Sn) with reduced cerium oxide species. The composite coatings thus obtained exhibit a smaller grain size, possess higher microhardness, and a lower melting point than the monolithic Sn coating. The electrical resistivity of the developed composites increases, however, but lies within the permissible limits for current lead-free solder applications. Also, an optimum balance of properties in terms of microhardness, adhesion, melting point and resistivity can be obtained with 0.9 wt.% cerium oxide in the Sn matrix, which enables potential applications in solder joints and packaging.

Toxicity of nickel and silver to Nostoc muscorum: interaction with ascorbic acid, glutathione, and sulfur-containing amino acids

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

Rai, L.C.; Raizada, M.

1987-08-01

Exposure of Nostoc muscorum to different concentrations of Ni and Ag brought about reduction in growth, carbon fixation, heterocyst production, and nitrogenase activity and increase in the loss of ions (K+, Na+). In an attempt to ameliorate the toxicity of test metals by ascorbic acid, glutathione, and sulfur-containing amino acids (L-cysteine and L-methionine), it was found that the level of protection by ascorbic acid and glutathione was more for Ag than Ni. However, metal-induced inhibition of growth and carbon fixation was equally ameliorated by methionine. But the level of protection by cysteine was quite different, i.e., 27% for Ni andmore » 22% for Ag. Protection of metal toxicity in N. muscorum by amino acids lends further support to self-detoxifying ability of cyanobacteria because they are known to synthesize all essential amino acids.« less

Microbial contributions to coupled arsenic and sulfur cycling in the acid-sulfide hot spring Champagne Pool, New Zealand.

PubMed

Hug, Katrin; Maher, William A; Stott, Matthew B; Krikowa, Frank; Foster, Simon; Moreau, John W

2014-01-01

Acid-sulfide hot springs are analogs of early Earth geothermal systems where microbial metal(loid) resistance likely first evolved. Arsenic is a metalloid enriched in the acid-sulfide hot spring Champagne Pool (Waiotapu, New Zealand). Arsenic speciation in Champagne Pool follows reaction paths not yet fully understood with respect to biotic contributions and coupling to biogeochemical sulfur cycling. Here we present quantitative arsenic speciation from Champagne Pool, finding arsenite dominant in the pool, rim and outflow channel (55-75% total arsenic), and dithio- and trithioarsenates ubiquitously present as 18-25% total arsenic. In the outflow channel, dimethylmonothioarsenate comprised ≤9% total arsenic, while on the outflow terrace thioarsenates were present at 55% total arsenic. We also quantified sulfide, thiosulfate, sulfate and elemental sulfur, finding sulfide and sulfate as major species in the pool and outflow terrace, respectively. Elemental sulfur concentration reached a maximum at the terrace. Phylogenetic analysis of 16S rRNA genes from metagenomic sequencing revealed the dominance of Sulfurihydrogenibium at all sites and an increased archaeal population at the rim and outflow channel. Several phylotypes were found closely related to known sulfur- and sulfide-oxidizers, as well as sulfur- and sulfate-reducers. Bioinformatic analysis revealed genes underpinning sulfur redox transformations, consistent with sulfur speciation data, and illustrating a microbial role in sulfur-dependent transformation of arsenite to thioarsenate. Metagenomic analysis also revealed genes encoding for arsenate reductase at all sites, reflecting the ubiquity of thioarsenate and a need for microbial arsenate resistance despite anoxic conditions. Absence of the arsenite oxidase gene, aio, at all sites suggests prioritization of arsenite detoxification over coupling to energy conservation. Finally, detection of methyl arsenic in the outflow channel, in conjunction with

AN EFFICIENT AND CHEMOSELECTIVE CBZ-PROTECTION OF AMINES USING SILICA-SULFURIC ACID AT ROOM TEMPERATURE

EPA Science Inventory

A simple, facile, and chemoselective N-benzyloxycarbonylation of amines using silica-sulfuric acid that proceeds under solvent-free conditions at room temperature has been achieved. These reactions are applicable to a wide variety of primary (aliphatic, cyclic) secondary amines, ...

A global three-dimensional model of the stratospheric sulfuric acid layer

NASA Technical Reports Server (NTRS)

Golombek, Amram; Prinn, Ronald G.

1993-01-01

A 3D model which encompasses SO2 production from OCS, followed by its oxidation to gaseous H2SO4, the condensation-evaporation equilibrium of gaseous and particulate H2SO4, and finally particle condensation and rainout, is presently used to study processes maintaining the nonvolcanically-perturbed stratosphere's sulfuric acid layer. A comparison of the results thus obtained with remotely sensed stratospheric aerosol extinction data shows the model to simulate the general behavior of stratospheric aerosol extinction.

Insights Into the Aqueous History of Mars from Acid-Sulfate Weathered Phyllosilicates

NASA Technical Reports Server (NTRS)

Craig, P. I.; Ming, D. W.; Rampe, E. B.; Morris, R. V.

2016-01-01

Phyllosilicates on Mars are thought to have formed during Mars' earliest Noachian geologic era (approx. 4.1-3.7 Ga). Sulfate formation, on the other hand, requires more acidic conditions which are thought to have occurred later during Mars' Hesperian era (approx. 3.7-3.0 Ga). Therefore, regions on Mars where phyllosilicates and sulfates are found in close proximity to each other provide evidence for the aqueous conditions during this global transition. Both phyllosilicates and sulfates form in the presence of water and thus give clues to the aqueous history of Mars and its potential for habitability. Phyllosilicates that formed during the Noachian era would have been weathered by the prevailing acidic conditions that define the Hesperian. Therefore, the purpose of this study is to characterize the alteration products of acid-sulfate weathered phyllosilicates in laboratory experiments, focusing on the Fe/Mg-smectites commonly identified on Mars. We also compare our results to observations of phyllosilicates and sulfates on Mars in regions such as Endeavour Crater and Mawrth Vallis to understand the formation process of sulfates and constrain the aqueous history of these regions.

Co-oxidation of the sulfur-containing amino acids in an autoxidizing lipid system

USGS Publications Warehouse

Wedemeyer, G.A.; Dollar, A.M.

1963-01-01

Oxidation of the sulfur amino acids by autoxidizing lipids was studied in a model system consisting of an amino acid dispersed in cold-pressed, molecularly distilled menhaden oil (20–80% w/w). Under all conditions investigated, cysteine was oxidized completely to cystine. Preliminary results suggest that at 110°C the oxidation follows first-order kinetics for at least the first 8 hr. A specific reaction rate constant of 0.25 per hour was calculated. When fatty acids were added to the system, cystine was oxidized to its thiosulfinate ester. When the fatty acid-cystine ratio was 1:2, oxidation of cystine was a maximum. No oxidation of cystine occurred unless either a fatty acid, volatile organic acid, or ethanol was added. Under the conditions investigated, methionine was not oxidized to either its sulfoxide or its sulfone.

Thoracic Duct Chylous Fistula Following Severe Electric Injury Combined with Sulfuric Acid Burns: A Case Report.

PubMed

Chang, Fei; Cheng, Dasheng; Qian, Mingyuan; Lu, Wei; Li, Huatao; Tang, Hongtai; Xia, Zhaofan

2016-10-11

BACKGROUND As patients with thoracic duct injuries often suffer from severe local soft tissue defects, integrated surgical treatment is needed to achieve damage repair and wound closure. However, thoracic duct chylous fistula is rare in burn patients, although it typically involves severe soft tissue damage in the neck or chest. CASE REPORT A 32-year-old male patient fell after accidentally contacting an electric current (380 V) and knocked over a barrel of sulfuric acid. The sulfuric acid continuously poured onto his left neck and chest, causing combined electrical and sulfuric acid burn injuries to his anterior and posterior torso, and various parts of his limbs (25% of his total body surface area). During treatment, chylous fistula developed in the left clavicular region, which we diagnosed as thoracic duct chylous fistula. We used diet control, intravenous nutritional support, and continuous somatostatin to reduce the chylous fistula output, and hydrophilic silver ion-containing dressings for wound coverage. A boneless muscle flap was used to seal the left clavicular cavity, and, integrated, these led to resolution of the chylous fistula. CONCLUSIONS Patients with severe electric or chemical burns in the neck or chest may be complicated with thoracic duct injuries. Although conservative treatment can control chylous fistula, wound cavity filling using a muscle flap is an effective approach for wound healing.

KINETIC ASPECTS OF CATION-ENHANCED AGGREGATION IN AQUEOUS HUMIC ACIDS. (R822832)

EPA Science Inventory

The cation-enhanced formation of hydrophobic domains in aqueous humic acids has been shown to be a slow process, consistent with the evolution and disintegration of humic acid configurations over periods lasting from days to weeks. After the addition of a magnesium salt to a humi...

The Biogeochemistry of Sulfur in Hydrothermal Systems

NASA Technical Reports Server (NTRS)

Schulte, Mitchell; Rogers, K. L.; DeVincenzi, Donald L. (Technical Monitor)

2001-01-01

The incorporation of sulfur into many biomolecules likely dates back to the development of the earliest metabolic strategies. Sulfur is common in enzymes and co-enzymes and is an indispensable structural component in many peptides and proteins. Early metabolism may have been heavily influenced by the abundance of sulfide minerals in hydrothermal systems. The incorporation of sulfur into many biomolecules likely dates back to the development of the earliest metabolic strategies. Sulfur is common in enzymes and co-enzymes and is an indispensable structural component in many peptides and proteins. Early metabolism may have been heavily influenced by the abundance of sulfide minerals in hydrothermal systems. Understanding how sulfur became prevalent in biochemical processes and many biomolecules requires knowledge of the reaction properties of sulfur-bearing compounds. We have previously estimated thermodynamic data for thiols, the simplest organic sulfur compounds, at elevated temperatures and pressures. If life began in hydrothermal environments, it is especially important to understand reactions at elevated temperatures among sulfur-bearing compounds and other organic molecules essential for the origin and persistence of life. Here we examine reactions that may have formed amino acids with thiols as reaction intermediates in hypothetical early Earth hydrothermal environments. (There are two amino acids, cysteine and methionine, that contain sulfur.) Our calculations suggest that significant amounts of some amino acids were produced in early Earth hydrothermal fluids, given reasonable concentrations H2, NH3, H2S and CO. For example, preliminary results indicate that glycine activities as high as 1 mmol can be reached in these systems at 100 C. Alanine formation from propanethiol is also a favorable reaction. On the other hand, the calculated equilibrium log activities of cysteine and serine from propanethiol are -21 and -19, respectively, at 100 C. These results

Expression of Genes Involved in Iron and Sulfur Respiration in a Novel Thermophilic Crenarchaeon Isolated from Acid-Sulfate-Chloride Geothermal Systems

NASA Astrophysics Data System (ADS)

Kozubal, M.; Macur, R.; Inskeep, W. P.

2007-12-01

Acidic geothermal springs within Yellowstone National Park (YNP) provide an excellent opportunity to study microbial populations and their relationship with geochemical processes such as redox cycling and biomineralization of iron. Fourteen acid-sulfate-chloride (ASC) and acid-sulfate (AS) geothermal springs located in (YNP) have been extensively characterized for aqueous chemistry, solid phase mineral deposition and microbial diversity and distribution. The oxidation of Fe(II) with oxygen as an electron acceptor is exergonic under these conditions, consequently, Fe(II) may be an important electron donor driving primary production in ASC and AS habitats, and products of biomineralization (e.g. Fe[III]-oxides of varying crystallinity and structure, as well as jarosite in some cases) are common in the outflow channels of these environments. Recently, we isolated a novel Metallosphaera-like microorganism (Metallosphaera strain MK1) from an ASC spring in Norris Geyser Basin, YNP. Clone libraries (16S rRNA gene) from multiple sites suggest that microorganisms closely related to strain MK1 (between 98-100 percent similarity) dominate many spring locations between 55-80 C. The in situ abiotic oxidation rate of Fe(II) has been shown to be very slow in these systems and Metallosphaera strain MK1 has been directly implicated in biotic Fe(II) oxidation. Metallosphaera strain MK1 has been submitted for full genome sequencing and is yielding gene sequences related to the terminal oxidases SOXABC and SOXM super-complex. In addition, sequences from a recently characterized terminal oxidase FOX complex involved in Fe(II) and pyrite oxidation from Sulfolobus metallicus have been found in Metallosphaera strain MK1. A protein complex analogous to Metallosphaera sedula has been identified in strain MK1 and this complex has also been expressed in cells grown on pyrite and Fe(II). Other sequences identified in Metallosphaera strain MK1 that are involved in respiration are the TQO

Comparative techno-economic analysis of steam explosion, dilute sulfuric acid, ammonia fiber explosion and biological pretreatments of corn stover.

PubMed

Baral, Nawa Raj; Shah, Ajay

2017-05-01

Pretreatment is required to destroy recalcitrant structure of lignocelluloses and then transform into fermentable sugars. This study assessed techno-economics of steam explosion, dilute sulfuric acid, ammonia fiber explosion and biological pretreatments, and identified bottlenecks and operational targets for process improvement. Techno-economic models of these pretreatment processes for a cellulosic biorefinery of 113.5 million liters butanol per year excluding fermentation and wastewater treatment sections were developed using a modelling software-SuperPro Designer. Experimental data of the selected pretreatment processes based on corn stover were gathered from recent publications, and used for this analysis. Estimated sugar production costs ($/kg) via steam explosion, dilute sulfuric acid, ammonia fiber explosion and biological methods were 0.43, 0.42, 0.65 and 1.41, respectively. The results suggest steam explosion and sulfuric acid pretreatment methods might be good alternatives at present state of technology and other pretreatment methods require research and development efforts to be competitive with these pretreatment methods. Copyright © 2017 Elsevier Ltd. All rights reserved.

New particle formation from sulfuric acid and amines: Similarities and differences between mono-, di-, and trimethylamines

NASA Astrophysics Data System (ADS)

Olenius, Tinja; Halonen, Roope; Kurtén, Theo; Henschel, Henning; Kupiainen-Määttä, Oona; Ortega, Ismael K.; Vehkamäki, Hanna; Riipinen, Ilona

2017-04-01

Amines are organic base species that are emitted to the atmosphere from both anthropogenic and natural sources. Both theoretical and laboratory studies suggest that mono-, di-, and trimethylamines (MMA, DMA, and TMA, respectively) are capable of enhancing the initial steps of sulfuric acid-driven aerosol particle formation much more strongly than ammonia (Kurtén et al., 2008; Jen et al., 2014). Despite the potential importance for atmospheric new particle formation, quantitative estimates on the emissions and thermochemical properties of amines remain relatively uncertain. Because of this and also due to computational reasons, recent large-scale modeling studies have treated sulfuric acid-amine nucleation by introducing a single surrogate amine species, the total emissions of which combine together MMA, DMA and TMA but which resembles DMA or TMA in its various properties (e.g. Bergman et al., 2015). On the other hand, there are likely to be differences in the potentials of the three amines to enhance particle formation, causing uncertainties to the lumping approach. Systematic comparisons are needed to evaluate how to treat these species in atmospheric models and to assess what level of simplification is justifiable. In this work, we study the differences and similarities of MMA, DMA and TMA by modeling nanoparticle formation from sulfuric acid, water, and each of the three amines. We simulate molecular cluster concentrations and formation rates at boundary layer conditions with a dynamic cluster population model using quantum chemistry-based cluster evaporation rates, and study the dependence of particle formation rate on precursor vapor concentrations, temperature and relative humidity. The results suggest that for the three amines, there are differences in the nucleation mechanism and hygroscopicity of molecular clusters. However, for DMA and TMA, formation of nanometer-sized particles and its dependence on ambient conditions is roughly similar: both

Effects of organic acids, amino acids and ethanol on the radio-degradation of patulin in an aqueous model system

NASA Astrophysics Data System (ADS)

Yun, Hyejeong; Lim, Sangyong; Jo, Cheorun; Chung, Jinwoo; Kim, Soohyun; Kwon, Joong-Ho; Kim, Dongho

2008-06-01

The effects of organic acids, amino acids, and ethanol on the radio-degradation of patulin by gamma irradiation in an aqueous model system were investigated. The patulin, dissolved in distilled water at a concentration of 50 ppm, was practically degraded by the gamma irradiation at the dose of 1.0 kGy, while 33% of the patulin remained in apple juice. In the aqueous model system, the radio-degradation of patulin was partially inhibited by the addition of organic acids, amino acids, and ethanol. The proportions of remaining patulin after irradiation with the dose of 1.0 kGy in the 1% solution of malic acid, citric acid, lactic acid, acetic acid, ascorbic acid, and ethanol were 31.4%, 2.3%, 31.2%, 6.1%, 50.8%, and 12.5%, respectively. During 30 days of storage, the remaining patulin was reduced gradually in the solution of ascorbic acid and malic acid compared to being stable in other samples. The amino acids, serine, threonine, and histidine, inhibited the radio-degradation of patulin. In conclusion, it was suggested that 1 kGy of gamma irradiation (recommended radiation doses for radicidation and/or quarantine in fruits) is effective for the reduction of patulin, but the nutritional elements should be considered because the radio-degradation effects are environment dependent.

Exploring Jupiter's icy moons with old techniques and big facilities - new insights on sulfuric acid hydrates

NASA Astrophysics Data System (ADS)

Maynard-Casely, H. E.; Avdeev, M.; Brand, H.; Wallwork, K.

2013-12-01

Sulfuric acid hydrates have been proposed to be abundant on the surface of Europa [1], and hence would be important planetary forming materials for this moon and its companions Ganymede and Callisto. Understanding of the surface features and subsurface of these moons could be advanced by firmer knowledge of the icy materials that comprise them [2], insight into which can be drawn from firmer knowledge of physical properties and phase behaviour of the candidate materials. We wish to present results from a study that started with the question ';What form of sulfuric acid hydrate would form on the surface of Europa'. The intrinsic hydrogen-domination of planetary ices, makes studying these materials with laboratory powder diffraction very challenging. Insights into their crystalline phase behavior and the extraction of a number of thermal and mechanical properties is often only accessible with high-flux synchrotron x-ray diffraction and utilization of the large scattering cross section with neutron diffraction. We have used the Powder Diffraction beamline at Australian synchrotron [4] and the Echidna (High-resolution neutron powder diffraction) instrument of the Australian Nuclear Science and Technology Organization, [5] to obtain an number of new insights into the crystalline phases formed from sulfruic acid and water mixtures. These instruments have enabled the discovery a new water-rich sulfuric acid hydrate form [6], improved structural characterisation of existing forms [7] and a charting the phase diagram of this fundamental binary system [8]. This has revealed exciting potential for understanding more about the surface of Europa from space, perhaps even providing a window into its past. [1] Carlson, R.W., R.E. Johnson, and M.S. Anderson, Science, 1999. 286(5437): p. 97-99. [2] Fortes, A.D. and M. Choukroun. Space Sci Rev, 2010. 153(1-4): p. 185-218. [3] Blake, D., et al., Space Sci Rev,, 2012. 170(1-4): p. 341-399. [4] Wallwork, K.S., Kennedy B. J. and Wang, D

Planetary Sources for Reducing Sulfur Compounds for Cyanosulfidic Origins of Life Chemistry

NASA Astrophysics Data System (ADS)

Ranjan, S.; Todd, Z. R.; Sutherland, J.; Sasselov, D. D.

2017-12-01

A key challenge in origin-of-life studies is understanding the chemistry that lead to the origin of the key biomolecules of life, such as the components of nucleic acids, sugars, lipids, and proteins. Prebiotic reaction networks based upon reductive homologation of nitriles (e.g., Patel et al. 2015), are building a tantalizing picture of sustained abiotic synthesis of activated ribonucleotides, amino acids and lipid precursors under environmental conditions thought to have been available on early Earth. Sulfidic anions in aqueous solution (e.g., HS-, HSO3-) under near-UV irradiation play important roles in these chemical pathways. However, the sources and availability of these anions on early Earth have not yet been quantitatively constrained. Here, we evaluate the potential for the atmosphere to serve as a source of sulfidic anions, via dissolution of volcanically-outgassed SO2 and H2S into water reservoirs. We combine photochemical modeling from the literature (Hu et al. 2013) with equilibrium chemistry calculations to place constraints on the partial pressures of SO2 and H2S required to reach the elevated concentrations of sulfidic anions (≥1 μM) thought to be necessary for prebiotic chemistry. We find that micromolar levels of SO2-derived anions (HSO3-, SO3(2-)) are possible through simple exposure of aqueous reservoirs like shallow lakes to the atmosphere, assuming total sulfur emission flux comparable to today. Millimolar levels of these compounds are available during the epochs of elevated volcanism, due to elevated sulfur emission flux. Radiative transfer modeling suggests the atmospheric sulfur will not block the near-UV radiation also required for the cyanosulfidic chemistry. However, H2S-derived anions (e.g., HS-) reach only sub-micromolar levels from atmospheric sources, meaning that prebiotic chemistry invoking such molecules must invoke specialized, local sources. Prebiotic chemistry invoking SO2-derived anions may be considered more robust than

Sulfur deficiency changes mycosporine-like amino acid (MAA) composition of Anabaena variabilis PCC 7937: a possible role of sulfur in MAA bioconversion.

PubMed

Singh, Shailendra P; Klisch, Manfred; Sinha, Rajeshwar P; Häder, Donat-Peter

2010-01-01

In the present investigation we show for the first time that bioconversion of a primary mycosporine-like amino acid (MAA) into a secondary MAA is regulated by sulfur deficiency in the cyanobacterium Anabaena variabilis PCC 7937. This cyanobacterium synthesizes the primary MAA shinorine (RT = 2.2 min, lambda(max) = 334 nm) under normal conditions (PAR + UV-A + UV-B); however, under sulfur deficiency, a secondary MAA palythine-serine (RT = 3.9 min, lambda(max) = 320 nm) appears. Addition of methionine to sulfur-deficient cultures resulted in the disappearance of palythine-serine, suggesting the role of primary MAAs under sulfur deficiency in recycling of methionine by donating the methyl group from the glycine subunit of shinorine to tetrahydrofolate to regenerate the methionine from homocysteine. This is also the first report for the synthesis of palythine-serine by cyanobacteria which has so far been reported only from corals. Addition of methionine also affected the conversion of mycosporine-glycine into shinorine, consequently, resulted in the appearance of mycosporine-glycine (RT = 3.6 min, lambda(max) = 310 nm). Our results also suggest that palythine-serine is synthesized from shinorine. Based on these results we propose that glycine decarboxylase is the potential enzyme that catalyzes the bioconversion of shinorine to palythine-serine by decarboxylation and demethylation of the glycine unit of shinorine.

Ultrasound-assisted analyte extraction for the determination of sulfate and elemental sulfur in zinc sulfide by different liquid chromatography techniques.

PubMed

Dash, K; Thangavel, S; Krishnamurthy, N V; Rao, S V; Karunasagar, D; Arunachalam, J

2005-04-01

The speciation and determination of sulfate (SO4(2-)) and elemental sulfur (S degree) in zinc sulfide (ZnS) using ion-chromatography (IC) and reversed-phase liquid chromatography (RPLC) respectively is described. Three sample pretreatment approaches were employed with the aim of determining sulfate: (i) conventional water extraction of the analyte; (ii) solid-liquid aqueous extraction with an ultrasonic probe; and (iii) elimination of the zinc sulfide matrix via ion-exchange dissolution (IED). The separation of sulfate was carried out by an anion-exchange column (IonPac AS17), followed by suppressed conductivity detection. Elemental sulfur was extracted ultrasonically from the acid treated sample solution into chloroform and separated on a reversed phase HPLC column equipped with a diode array detector (DAD) at 264 nm. The achievable solid detection limits for sulfate and sulfur were 35 and 10 microg g(-1) respectively.

Effects of simulated rain acidified with sulfuric acid on host-parasite interactions

Treesearch

D. S. Shriner

1976-01-01

Wind-blown rain, rain splash, and films of free moisture play important roles in the epidemiology of many plant diseases. The effects of simulated rain acidified with sulfuric acid were studied on several host-parasite systems. Plants were exposed, in greenhouse or field, to simulated rain of pH 3.2 ? 0.1 or pH 6.0 ? 0.2. Simulated "rain" of pH 3.2 resulted...

Inhibition of citral degradation in an acidic aqueous environment by polyoxyethylene alkylether surfactants.

PubMed

Maswal, Masrat; Dar, Aijaz Ahmad

2013-06-15

Citral is a flavour component widely used in food and cosmetic industries, but is chemically unstable and degrades over time in aqueous solutions due to acid-catalysed and oxidative reactions leading to loss of desirable flavour. The present study reveals the effect of non-ionic micellar solutions of Brij30 and Brij35 on the extent of solubilisation and stabilisation of citral. The rate of chemical degradation of citral in acidic aqueous solutions was found to be highest, which was subsequently reduced significantly within these studied surfactant systems, suggesting protection of citral from an acidic environment once it is incorporated into the micelles. The work concludes that polyoxyethylene alkylether surfactants with lower HLB value, less dense hydrophilic corona and more hydrophobic core volume are efficient in solubilising and stabilising citral against an acidic environment. Copyright © 2012 Elsevier Ltd. All rights reserved.

Target loads of atmospheric sulfur and nitrogen deposition for protection of acid sensitive aquatic resources in the Adirondack Mountains, New York

USGS Publications Warehouse

Sullivan, T.J.; Cosby, B.J.; Driscoll, C.T.; McDonnell, T.C.; Herlihy, A.T.; Burns, Douglas A.

2012-01-01

The dynamic watershed acid-base chemistry model of acidification of groundwater in catchments (MAGIC) was used to calculate target loads (TLs) of atmospheric sulfur and nitrogen deposition expected to be protective of aquatic health in lakes in the Adirondack ecoregion of New York. The TLs were calculated for two future dates (2050 and 2100) and three levels of protection against lake acidification (acid neutralizing capacity (ANC) of 0, 20, and 50 eq L -1). Regional sulfur and nitrogen deposition estimates were combined with TLs to calculate exceedances. Target load results, and associated exceedances, were extrapolated to the regional population of Adirondack lakes. About 30% of Adirondack lakes had simulated TL of sulfur deposition less than 50 meq m -2 yr to protect lake ANC to 50 eq L -1. About 600 Adirondack lakes receive ambient sulfur deposition that is above this TL, in some cases by more than a factor of 2. Some critical criteria threshold values were simulated to be unobtainable in some lakes even if sulfur deposition was to be decreased to zero and held at zero until the specified endpoint year. We also summarize important lessons for the use of target loads in the management of acid-impacted aquatic ecosystems, such as those in North America, Europe, and Asia. Copyright 2012 by the American Geophysical Union.

Direct sensing of fluoride in aqueous solutions using a boronic acid based sensor.

PubMed

Wu, Xin; Chen, Xuan-Xuan; Song, Bing-Nan; Huang, Yan-Jun; Ouyang, Wen-Juan; Li, Zhao; James, Tony D; Jiang, Yun-Bao

2014-11-21

Binding of the fluoride ion triggers aggregation of a pyreneboronic acid-catechol ensemble in acidic aqueous solutions, giving rise to intense excimer emission, allowing for sensitive fluoride ion sensing at ppm levels, with an apparent fluoride binding constant higher than 10(3) M(-1) which is unprecedented for boronic acid sensors in water.

Aqueous-Phase Photochemical Production of Oxidants in Atmospheric Waters.

NASA Astrophysics Data System (ADS)

Allen, John Morrison

1992-01-01

The photochemical formation and subsequent reactions of oxidants plays an important role in the overall chemistry of the atmosphere. Much of the interest in atmospheric oxidation reactions has been fueled by the environmental consequences of the oxidation of sulfur dioxide (SO _2) forming sulfuric acid (H_2 SO_4). Oxidation reactions also play a crucial role in other atmospheric chemical transformations such as: (1) the destruction of tropospheric ozone, (2) redox cycling of transition metals, and (3) oxidation of organic compounds. Much of the research pertaining to atmospheric oxidant formation and the reactions that these oxidants undergo has centered upon gas-phase photochemical oxidant formation and: (1) subsequent reactions in the gas phase, or (2) partitioning of oxidants into cloud and fog drops and subsequent reactions in the aqueous phase. Only a very limited amount of data is available concerning aqueous -phase photochemical sources of oxidants in cloud and fog drops. The focus of one aspect of the work presented in this dissertation is upon the aqueous-phase sunlight photochemical formation of oxidants in authentic cloud and fog water samples from across the United States and Canada. It will be demonstrated that atmospheric waters typically absorb solar ultraviolet radiation at wavelengths ranging from 290 to 340 nm. This absorption is due to the presence of chemical constituents in the cloud and fog waters that contain chromophoric functional groups that give rise to the formation of: (1) singlet molecular oxygen O_2(^1Delta_ {rm g}), (2) peroxyl radicals (HO _2cdot and RO_2 cdot), (3) peroxides (HOOH, ROOH, and ROOR '), and (4) hydroxyl radical ( cdotOH). This work will demonstrate that aqueous-phase photochemical reactions are a significant and in some cases dominant source of these oxidants in cloud and fog drops. The transition metal catalyzed oxidation of SO _2 to H_2SO _4 by molecular oxygen has been extensively studied. This reaction is thought

Production of spent mushroom substrate hydrolysates useful for cultivation of Lactococcus lactis by dilute sulfuric acid, cellulase and xylanase treatment.

PubMed

Qiao, Jian-Jun; Zhang, Yan-Fei; Sun, Li-Fan; Liu, Wei-Wei; Zhu, Hong-Ji; Zhang, Zhijun

2011-09-01

Spent mushroom substrate (SMS) was treated with dilute sulfuric acid followed by cellulase and xylanase treatment to produce hydrolysates that could be used as the basis for media for the production of value added products. A L9 (3(4)) orthogonal experiment was performed to optimize the acid treatment process. Pretreatment with 6% (w/w) dilute sulfuric acid at 120°C for 120 min provided the highest reducing sugar yield of 267.57 g/kg SMS. No furfural was detected in the hydrolysates. Exposure to 20PFU of cellulase and 200 XU of xylanase per gram of pretreated SMS at 40°C resulted in the release of 79.85 g/kg or reducing sugars per kg acid pretreated SMS. The dilute sulfuric acid could be recycled to process fresh SMS four times. SMS hydrolysates neutralized with ammonium hydroxide, sodium hydroxide, or calcium hydroxide could be used as the carbon source for cultivation of Lactococcus lactis subsp. lactis W28 and a cell density of 2.9×10(11)CFU/mL could be obtained. The results provide a foundation for the development of value-added products based on SMS. Copyright © 2011 Elsevier Ltd. All rights reserved.

FTIR studies of low temperature sulfuric acid aerosols

NASA Technical Reports Server (NTRS)

Anthony, S. E.; Tisdale, R. T.; Disselkamp, R. S.; Tolbert, M. A.; Wilson, J. C.

1995-01-01

Sub-micrometer sized sulfuric acid H2SO4 particles were generated using a constant output atomizer source. The particles were then exposed to water vapor before being injected into a low temperature cell. Multipass transmission Fourier Transformation Infrared (FTIR) spectroscopy was used to determine the phase and composition of the aerosols as a function of time for periods of up to five hours. Binary H2SO4H2O aerosols with compositions from 35 to 95 wt % H2SO4 remained liquid for over 3 hours at room temperatures ranging from 189-240 K. These results suggest that it is very difficut to freeze SSAs via homogeneous nucleation. Attempts to form aerosols more dilute than 35 wt % H2SO4 resulted in ice formation.

[Quality assessment of sulfur-fumigated paeoniae alba radix].

PubMed

Wang, Zhao; Chen, Yu-Wu; Wang, Qiong; Sun, Lei; Xu, Wei-Yi; Jin, Hong-Yu; Ma, Shuang-Cheng

2014-08-01

The samples of sulfur-fumigated Paeoniae Alba Radix acquired both by random spot check from domestic market and self-production by the research group in the laboratory were used to evaluate the effects of sulphur fumigation on the quality of Paeoniae Alba Radix by comparing sulfur-fumigated degree and character, the content of paeoniflorin and paeoniflorin sulfurous acid ester, and changes of the fingerprint. We used methods in Chinese Pharmacopeia to evaluate the character of sulfur-fumigated Paeoniae Alba Radix and determinate the content of aulfur-fumigated paeoniflorin. LC-MS method was used to analyze paeoniflorin-converted products. HPLC fingerprint methods were established to evaluate the differences on quality by similarity. Results showed that fumigated Paeoniae Alba Radix became white and its unique fragrance disappeared, along with the production of pungent sour gas. It also had a significant effect on paeoniflorin content. As sulfur smoked degree aggravated, paeoniflorin content decreased subsequently, some of which turned into paeoniflorin sulfurous acid ester, and this change was not reversible. Fingerprint also showed obvious changes. Obviously, sulfur fumigation had severe influence on the quality of Paeoniae Alba Radix, but we can control the quality of the Paeoniae Alba Radix by testing the paeoniflorin sulfurous acid ester content.

Sulfur passivation techniques for III-V wafer bonding

NASA Astrophysics Data System (ADS)

Jackson, Michael James

The use of direct wafer bonding in a multijunction III-V solar cell structure requires the formation of a low resistance bonded interface with minimal thermal treatment. A wafer bonded interface behaves as two independent surfaces in close proximity, hence a major source of resistance is Fermi level pinning common in III-V surfaces. This study demonstrates the use of sulfur passivation in III-V wafer bonding to reduce the energy barrier at the interface. Two different sulfur passivation processes are addressed. A dry sulfur passivation method that utilizes elemental sulfur vapor activated by ultraviolet light in vacuum is compared with aqueous sulfide and native oxide etch treatments. Through the addition of a sulfur desorption step in vacuum, the UV-S treatment achieves bondable surfaces free of particles contamination or surface roughening. X-ray photoelectron spectroscopy measurements of the sulfur treated GaAs surfaces find lower levels of oxide and the appearance of sulfide species. After 4 hrs of air exposure, the UV-S treated GaAs actually showed an increase in the amount of sulfide bonded to the semiconductor, resulting in less oxidation compared to the aqueous sulfide treatment. Large area bonding is achieved for sulfur treated GaAs / GaAs and InP / InP with bulk fracture strength achieved after annealing at 400 °C and 300 °C respectively, without large compressive forces. The electrical conductivity across a sulfur treated 400 °C bonded n-GaAs/n-GaAs interface significantly increased with a short anneal (1-2 minutes) at elevated temperatures (50--600 °C). Interfaces treated with the NH4OH oxide etch, on the other hand, exhibited only mild improvement in accordance with previously published studies in this area. TEM and STEM images revealed similar interfacial microstructure changes with annealing for both sulfur treated and NH4OH interfaces, whereby some areas have direct semiconductor-semiconductor contact without any interfacial layer. Fitting the

Determination of sulfuric acid concentration for anti-cavitation characteristics of Al alloy by two step anodizing process to forming nano porous.

PubMed

Lee, Seung-Jun; Kim, Seong-Kweon; Jeong, Jae-Yong; Kim, Seong-Jong

2014-12-01

Al alloy is a highly active metal but forms a protective oxide film having high corrosion resistance in atmosphere environment. However, the oxide film is not suitable for practical use, since the thickness of the film is not uniform and it is severly altered with formation conditions. This study focused on developing an aluminum anodizing layer having hardness, corrosion resistance and abrasion resistance equivalent to a commercial grade protective layer. Aluminum anodizing layer was produced by two-step aluminum anodizing oxide (AAO) process with different sulfuric acid concentrations, and the cavitation characteristics of the anodized coating layer was investigated. In hardness measurement, the anodized coating layer produced with 15 vol.% of sulfuric acid condition had the highest value of hardness but exhibited poor cavitation resistance due to being more brittle than those with other conditions. The 10 vol.% of sulfuric acid condition was thus considered to be the optimum condition as it had the lowest weight loss and damage depth.

Preparing ultrafine PbS powders from the scrap lead-acid battery by sulfurization and inert gas condensation

NASA Astrophysics Data System (ADS)

Xia, Huipeng; Zhan, Lu; Xie, Bing

2017-02-01

A novel method for preparing ultrafine PbS powders involving sulfurization combined with inert gas condensation is developed in this paper, which is applicable to recycle Pb from lead paste of spent lead-acid batteries. Initially, the effects of the evaporation and condensation temperature, the inert gas pressure, the condensation distance and substrate on the morphology of as-obtained PbS ultrafine particles are intensively investigated using sulfur powders and lead particles as reagents. Highly dispersed and homogeneous PbS nanoparticles can be prepared under the optimized conditions which are 1223 K heating temperature, 573 K condensation temperature, 100 Pa inert gas pressure and 60 cm condensation distance. Furthermore, this method is successfully applied to recycle Pb from the lead paste of spent lead acid battery to prepare PbS ultrafine powders. This work does not only provide the theoretical fundamental for PbS preparation, but also provides a novel and efficient method for recycling spent lead-acid battery with high added-value products.

Influence of liquid and gas flow rates on sulfuric acid mist removal from air by packed bed tower

PubMed Central

2012-01-01

The possible emission of sulfuric acid mists from a laboratory scale, counter-current packed bed tower operated with a caustic scrubbing solution was studied. Acid mists were applied through a local exhaust hood. The emissions from the packed bed tower were monitored in three different categories of gas flow rate as well as three liquid flow rates, while other influencing parameters were kept almost constant. Air sampling and sulfuric acid measurement were carried out iso-kinetically using USEPA method 8. The acid mists were measured by the barium-thorin titration method. According to the results when the gas flow rate increased from 10 L/s to 30 L/s, the average removal efficiency increased significantly (p < 0.001) from 76.8 ± 1.8% to 85.7 ± 1.2%. Analysis of covariance method followed by Tukey post-hoc test of 92 tests did not show a significant change in removal efficiency between liquid flow rates of 1.5, 2.5 and 3.5 L/min (p = 0.811). On the other hand, with fixed pressure loss across the tower, by increasing the liquid/gas (L/G) mass ratio, the average removal efficiency decreased significantly (p = 0.001) from 89.9% at L/G of <2 to 83.1% at L/G of 2–3 and further to 80.2% at L/G of >3, respectively. L/G of 2–3 was recommended for designing purposes of a packed tower for sulfuric acid mists and vapors removal from contaminated air stream. PMID:23369487

Involvement of Intermediate Sulfur Species in Biological Reduction of Elemental Sulfur under Acidic, Hydrothermal Conditions

PubMed Central

Druschel, Gregory K.

2013-01-01

The thermoacidophile and obligate elemental sulfur (S80)-reducing anaerobe Acidilobus sulfurireducens 18D70 does not associate with bulk solid-phase sulfur during S80-dependent batch culture growth. Cyclic voltammetry indicated the production of hydrogen sulfide (H2S) as well as polysulfides after 1 day of batch growth of the organism at pH 3.0 and 81°C. The production of polysulfide is likely due to the abiotic reaction between S80 and the biologically produced H2S, as evinced by a rapid cessation of polysulfide formation when the growth temperature was decreased, inhibiting the biological production of sulfide. After an additional 5 days of growth, nanoparticulate S80 was detected in the cultivation medium, a result of the hydrolysis of polysulfides in acidic medium. To examine whether soluble polysulfides and/or nanoparticulate S80 can serve as terminal electron acceptors (TEA) supporting the growth of A. sulfurireducens, total sulfide concentration and cell density were monitored in batch cultures with S80 provided as a solid phase in the medium or with S80 sequestered in dialysis tubing. The rates of sulfide production in 7-day-old cultures with S80 sequestered in dialysis tubing with pore sizes of 12 to 14 kDa and 6 to 8 kDa were 55% and 22%, respectively, of that of cultures with S80 provided as a solid phase in the medium. These results indicate that the TEA existed in a range of particle sizes that affected its ability to diffuse through dialysis tubing of different pore sizes. Dynamic light scattering revealed that S80 particles generated through polysulfide rapidly grew in size, a rate which was influenced by the pH of the medium and the presence of organic carbon. Thus, S80 particles formed through abiological hydrolysis of polysulfide under acidic conditions appeared to serve as a growth-promoting TEA for A. sulfurireducens. PMID:23335768

Study of thermodynamic and acoustic behaviour of nicotinic acid in binary aqueous mixtures of D-lactose

NASA Astrophysics Data System (ADS)

Sharma, Ravi; Thakur, R. C.

2017-07-01

In the present study, the thermodynamic properties such as partial molar volumes, partial molar expansibilities, partial molar compressibilities, partial molar heat capacities and isobaric thermal expansion coefficient of different solutions of nicotinic acid in binary aqueous mixtures of D-lactose have been determined at different temperatures (298.15, 303.15, 308.15, 313.15) K. Masson's equation is used to interpret the data in terms of solute-solute and solute-solvent interactions. In the present study it has been found that nicotinic acid behaves as structure maker in aqueous and binary aqueous mixtures of D-lactose.

Mechanisms leading to oligomers and SOA through aqueous photooxidation: insights from OH radical oxidation of acetic acid

NASA Astrophysics Data System (ADS)

Tan, Y.; Lim, Y. B.; Altieri, K. E.; Seitzinger, S. P.; Turpin, B. J.

2011-06-01

Previous experiments have demonstrated that the aqueous OH radical oxidation of methylglyoxal produces low volatility products including oxalate and oligomers. These products are found predominantly in the particle phase in the atmosphere, suggesting that methylglyoxal is a precursor of secondary organic aerosol (SOA). Acetic acid is an important intermediate in aqueous methylglyoxal oxidation and a ubiquitous product of gas phase photochemistry, making it a potential "aqueous" SOA precursor in its own right. Altieri et al. (2008) proposed that acetic acid was the precursor of oligoesters observed in methylglyoxal oxidation. However, the fate of acetic acid upon aqueous-phase oxidation is not well understood. In this research, acetic acid at concentrations relevant to atmospheric waters (20 μM-10 mM) was oxidized by OH radical. Products were analyzed by ion chromatography (IC), electrospray ionization mass spectrometry (ESI-MS), and IC-ESI-MS. The formation of glyoxylic, glycolic, and oxalic acids were observed. In contrast to methylglyoxal oxidation, succinic acid and oligomers were not detected. Using results from these and methylglyoxal + OH radical experiments, radical mechanisms responsible for oligomer formation from methylglyoxal oxidation in clouds and wet aerosols are proposed. The importance of acetic acid/acetate as an SOA precursor is also discussed. We hypothesize that this and similar chemistry is central to the daytime formation of oligomers in wet aerosols.

Mechanistic study of fulvic acid assisted propranolol photodegradation in aqueous solution.

PubMed

Makunina, Maria P; Pozdnyakov, Ivan P; Chen, Yong; Grivin, Vyacheslav P; Bazhin, Nikolay M; Plyusnin, Victor F

2015-01-01

Laser flash (355 nm) and stationary (365 nm) photolysis were used to study the mechanisms of propranolol photolysis in the presence of fulvic acid in aqueous solutions. The FA-assisted photodegradation of propranolol was observed using UV-A irradiation (where propranolol is stable). Direct evidence indicated that the photodegradation resulted from the static quenching of the FA triplet state by propranolol via the electron transfer mechanism. The triplet state yield (ϕT≈0.6%) and the T-T absorption coefficient (ɛT(620 nm)≈5×10(4) M(-1) cm(-1)) were estimated for the first time by modeling the yields of the FA triplet state in the presence of propranolol. Thus, fulvic acid is a promising agent for accelerating propranolol photodegradation in aqueous solutions under UV-A light irradiation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Phosphate sorption and desorption on pyrite in primitive aqueous scenarios: relevance of acidic --> alkaline transitions.

PubMed

de Souza-Barros, Fernando; Braz-Levigard, Raphael; Ching-San, Yonder; Monte, Marisa M B; Bonapace, José A P; Montezano, Viviane; Vieyra, Adalberto

2007-02-01

Phosphate (P(i)) sorption assays onto pyrite in media simulating primeval aquatic scenarios affected by hydrothermal emissions, reveal that acidic conditions favour P(i) sorption whereas mild alkaline media--as well as those simulating sulfur oxidation to SO(2-) (4)--revert this capture process. Several mechanisms relevant to P(i) availability in prebiotic eras are implicated in the modulation of these processes. Those favouring sorption are: (a) hydrophobic coating of molecules, such as acetate that could be formed in the vicinity of hydrothermal vents; (b) water and Mg(2+) bridging in the interface mineral-aqueous media; (c) surface charge neutralization by monovalent cations (Na+ and K+). The increase of both the medium pH and the SO(2-) (4) trapping by the mineral interface would provoke the release of sorbed P(i) due to charge polarization. Moreover it is shown that P(i) self-modulates its sorption, a mechanism that depends on the abundance of SO(2-) (4) in the interface. The relevance of the proposed mechanisms of P(i) capture, release and trapping arises from the need of abundant presence of this molecule for primitive phosphorylations, since--similarly to contemporary aqueous media--inorganic phosphate concentrations in primitive seas should have been low. It is proposed that the presence of sulphide minerals with high affinity to P(i) could have trapped this molecule in an efficient manner, allowing its concentration in specific niches. In these niches, the conditions studied in the present work would have been relevant for its availability in soluble form, specially in primitive insulated systems with pH gradients across the wall.

Developing porous carbon with dihydrogen phosphate groups as sulfur host for high performance lithium sulfur batteries

NASA Astrophysics Data System (ADS)

Cui, Yanhui; Zhang, Qi; Wu, Junwei; Liang, Xiao; Baker, Andrew P.; Qu, Deyang; Zhang, Hui; Zhang, Huayu; Zhang, Xinhe

2018-02-01

Carbon matrix (CM) derived from biomass is low cost and easily mass produced, showing great potential as sulfur host for lithium sulfur batteries. In this paper we report on a dihydrogen phosphate modified CM (PCM-650) prepared from luffa sponge (luffa acutangula) by phosphoric acid treatment. The phosphoric acid not only increases the surface area of the PCM-650, but also introduces dihydrogen phosphate onto PCM-650 (2.28 at% P). Sulfur impregnated (63.6 wt%) PCM-650/S, in comparison with samples with less dihydrogen phosphate LPCM-650/S, shows a significant performance improvement. XPS analysis is conducted for sulfur at different stages, including sulfur (undischarged), polysulfides (discharge to 2.1 V) and short chain sulfides (discharge to 1.7 V). The results consistently show chemical shifts for S2p in PCM-650, suggesting an enhanced adsorption effect. Furthermore, density functional theory (DFT) calculations is used to clarify the molecular binding: carbon/sulfur (0.86 eV), carbon/Li2S (0.3 eV), CH3-O-PO3H2/sulfur (1.24 eV), and CH3-O-PO3H2/Li2S (1.81 eV). It shows that dihydrogen phosphate group can significantly enhance the binding with sulfur and sulfide, consistent with XPS results. Consequently a CM functionalised with dihydrogen phosphate shows great potential as the sulfur host in a Li-S battery.

Sulfur assimilation and the role of sulfur in plant metabolism: a survey.

PubMed

Droux, Michel

2004-01-01

Sulfur occurs in two major amino-acids, cysteine (Cys) and methionine (Met), essential for the primary and secondary metabolism of the plant. Cys, as the first carbon/nitrogen-reduced sulfur product resulting from the sulfate assimilation pathway, serves as a sulfur donor for Met, glutathione, vitamins, co-factors, and sulfur compounds that play a major role in the growth and development of plant cells. This sulfur imprinting occurs in a myriad of fundamental processes, from photosynthesis to carbon and nitrogen metabolism. Cys and Met occur in proteins, with the former playing a wide range of functions in proteins catalysis. In addition, the sulfur atom in proteins forms part of a redox buffer, as for glutathione, through specific detoxification/protection mechanisms. In this review, a survey of sulfur assimilation from sulfate to Cys, Met and glutathione is presented with highlights on open questions on their respective biosynthetic pathways and regulations that derived from recent findings. These are addressed at the biochemical and molecular levels with respect to the fate of Cys and Met throughout the plant-cell metabolism.

Gamma-irradiation of malic acid in aqueous solutions. [prebiotic significance

NASA Technical Reports Server (NTRS)

Negron-Mendoza, A.; Graff, R. L.; Ponnamperuma, C.

1980-01-01

The gamma-irradiation of malic acid in aqueous solutions was studied under initially oxygenated and oxygen-free conditions in an attempt to determine the possible interconversion of malic acid into other carboxylic acids, specifically those associated with Krebs cycle. The effect of dose on product formation of the system was investigated. Gas-liquid chromatography combined with mass spectrometry was used as the principal means of identification of the nonvolatile products. Thin layer chromatography and direct probe mass spectroscopy were also employed. The findings show that a variety of carboxylic acids are formed, with malonic and succinic acids in greatest abundance. These products have all been identified as being formed in the gamma-irradiation of acetic acid, suggesting a common intermediary. Since these molecules fit into a metabolic cycle, it is strongly suggestive that prebiotic pathways provided the basis for biological systems.

Theoretical studies of the marine sulfur cycle

NASA Technical Reports Server (NTRS)

Toon, Owen B.; Kasting, James B.; Liu, May S.

1985-01-01

Several reduced sulfur compounds are produced by marine organisms and then enter the atmosphere, where they are oxidized and ultimately returned to the ocean or the land. The oceanic dimethyl sulfide (DMS) flux, in particular, represents a significant fraction of the annual global sulfur input to the atmosphere. In the atmosphere, this gas is converted to sulfur dioxide (SO2), methane sulfonic acid, and other organic acids which are relatively stable and about which little is known. SO2 is a short lived gas which, in turn, is converted to sulfuric acid and other sulfate compounds which contribute significantly to acid rain. Because of the complexity of the sulfur system, it is not well understood even in the unperturbed atmosphere. However, a number of new observations and experiments have led to a significant increase in the understanding of this system. A number of one dimensional model experiments were conducted on the gas phase part of the marine sulfur cycle. The results indicate the measured concentration of DMS and the amplitude of its diurnal cycle are in agreement with estimates of its global flux. It was also found that DMS can make a large contribution to the background SO2 concentration in the free troposphere. Estimates of CS2 concentrations in the atmosphere are inconsistent with estimated fluxes; however, measured reaction rates are consistent with the observed steep tropospheric gradient in CS2. Observations of CS2 are extremely sparse. Further study is planned.

Acid Sulfate Alteration on Mars

NASA Technical Reports Server (NTRS)

Ming, D. W.; Morris, R. V.

2016-01-01

A variety of mineralogical and geochemical indicators for aqueous alteration on Mars have been identified by a combination of surface and orbital robotic missions, telescopic observations, characterization of Martian meteorites, and laboratory and terrestrial analog studies. Acid sulfate alteration has been identified at all three landing sites visited by NASA rover missions (Spirit, Opportunity, and Curiosity). Spirit landed in Gusev crater in 2004 and discovered Fe-sulfates and materials that have been extensively leached by acid sulfate solutions. Opportunity landing on the plains of Meridiani Planum also in 2004 where the rover encountered large abundances of jarosite and hematite in sedimentary rocks. Curiosity landed in Gale crater in 2012 and has characterized fluvial, deltaic, and lacustrine sediments. Jarosite and hematite were discovered in some of the lacustrine sediments. The high elemental abundance of sulfur in surface materials is obvious evidence that sulfate has played a major role in aqueous processes at all landing sites on Mars. The sulfate-rich outcrop at Meridiani Planum has an SO3 content of up to 25 wt.%. The interiors of rocks and outcrops on the Columbia Hills within Gusev crater have up to 8 wt.% SO3. Soils at both sites generally have between 5 to 14 wt.% SO3, and several soils in Gusev crater contain around 30 wt.% SO3. After normalization of major element compositions to a SO3-free basis, the bulk compositions of these materials are basaltic, with a few exceptions in Gusev crater and in lacustrine mudstones in Gale crater. These observations suggest that materials encountered by the rovers were derived from basaltic precursors by acid sulfate alteration under nearly isochemical conditions (i.e., minimal leaching). There are several cases, however, where acid sulfate alteration minerals (jarosite and hematite) formed in open hydrologic systems, e.g., in Gale crater lacustrine mudstones. Several hypotheses have been suggested for the

Volatility of organic aerosol: evaporation of ammonium sulfate/succinic acid aqueous solution droplets.

PubMed

Yli-Juuti, Taina; Zardini, Alessandro A; Eriksson, Axel C; Hansen, Anne Maria K; Pagels, Joakim H; Swietlicki, Erik; Svenningsson, Birgitta; Glasius, Marianne; Worsnop, Douglas R; Riipinen, Ilona; Bilde, Merete

2013-01-01

Condensation and evaporation modify the properties and effects of atmospheric aerosol particles. We studied the evaporation of aqueous succinic acid and succinic acid/ammonium sulfate droplets to obtain insights on the effect of ammonium sulfate on the gas/particle partitioning of atmospheric organic acids. Droplet evaporation in a laminar flow tube was measured in a Tandem Differential Mobility Analyzer setup. A wide range of droplet compositions was investigated, and for some of the experiments the composition was tracked using an Aerosol Mass Spectrometer. The measured evaporation was compared to model predictions where the ammonium sulfate was assumed not to directly affect succinic acid evaporation. The model captured the evaporation rates for droplets with large organic content but overestimated the droplet size change when the molar concentration of succinic acid was similar to or lower than that of ammonium sulfate, suggesting that ammonium sulfate enhances the partitioning of dicarboxylic acids to aqueous particles more than currently expected from simple mixture thermodynamics. If extrapolated to the real atmosphere, these results imply enhanced partitioning of secondary organic compounds to particulate phase in environments dominated by inorganic aerosol.

Volatility of Organic Aerosol: Evaporation of Ammonium Sulfate/Succinic Acid Aqueous Solution Droplets

PubMed Central

2013-01-01

Condensation and evaporation modify the properties and effects of atmospheric aerosol particles. We studied the evaporation of aqueous succinic acid and succinic acid/ammonium sulfate droplets to obtain insights on the effect of ammonium sulfate on the gas/particle partitioning of atmospheric organic acids. Droplet evaporation in a laminar flow tube was measured in a Tandem Differential Mobility Analyzer setup. A wide range of droplet compositions was investigated, and for some of the experiments the composition was tracked using an Aerosol Mass Spectrometer. The measured evaporation was compared to model predictions where the ammonium sulfate was assumed not to directly affect succinic acid evaporation. The model captured the evaporation rates for droplets with large organic content but overestimated the droplet size change when the molar concentration of succinic acid was similar to or lower than that of ammonium sulfate, suggesting that ammonium sulfate enhances the partitioning of dicarboxylic acids to aqueous particles more than currently expected from simple mixture thermodynamics. If extrapolated to the real atmosphere, these results imply enhanced partitioning of secondary organic compounds to particulate phase in environments dominated by inorganic aerosol. PMID:24107221

Photooxidation products of polycyclic aromatic compounds containing sulfur.

PubMed

Bobinger, Stefan; Andersson, Jan T

2009-11-01

Photooxidation of crude oil components is an important process that removes pollutants from the environment. Polycyclic aromatic compounds (PACs) are known to be toxic to many life forms, but little is known about their photooxidation products in the aqueous phase. We here identify a large number of photoproducts from 11 benzothiophenes, a polycyclic aromatic sulfur heterocycle that is a major representative of PACs in crude oil. The investigated compounds contain two to four methyl groups and an ethyl or an n-octyl group. In water, the products arise through oxidation of alkyl side chains to aldehydes and carboxylic acids or through an opening in one of the aromatic rings. The product analysis was performed using gas chromatography with mass spectrometric or atomic emission detection. The main product is always a sulfobenzoic acid, which strongly lowers the pH of the solution. With long alkyl substituents, surfactants are formed, which may possess solubilizing properties in water. The larger the number of alkyl groups, the faster is the photooxidation. Several of the identified acidic compounds were also found when whole crude oil was photooxidized, showing that simulation with individual compounds reflects the situation in whole crude.

Inhomogeneous models of the Venus clouds containing sulfur

NASA Technical Reports Server (NTRS)

Smith, S. M.; Pollack, J. B.; Giver, L. P.; Cuzzi, J. N.; Podolak, M.

1979-01-01

Based on the suggestion that elemental sulfur is responsible for the yellow color of Venus, calculations are compared at 3.4 microns of the reflectivity phase function of two sulfur containing inhomogeneous cloud models with that of a homogeneous model. Assuming reflectivity observations with 25% or less total error, comparison of the model calculations leads to a minimum detectable mass of sulfur equal to 7% of the mass of sulfuric acid for the inhomogeneous drop model. For the inhomogeneous cloud model the comparison leads to a minimum detectable mass of sulfur between 17% and 38% of the mass of the acid drops, depending upon the actual size of the large particles. It is concluded that moderately accurate 3.4 microns reflectivity observations are capable of detecting quite small amounts of elemental sulfur at the top of the Venus clouds.

An alternative method to remove PEO-PPO-PEO template in organic-inorganic mesoporous nanocomposites by sulfuric acid extraction

NASA Astrophysics Data System (ADS)

Zhuang, Xin; Qian, Xufang; Lv, Jiahui; Wan, Ying

2010-06-01

Sulfuric acid is used as an extraction agent to remove PEO-PPO-PEO templates in the organic-inorganic mesoporous nanocomposites from the triconstituent co-assembly which includes the low-polymerized phenolic resins, TEOS and triblock copolymer F127. The XRD and TEM results show well ordered mesostructure after extraction with sulfuric acid. As followed from the N 2 sorption isotherms the extracted composites possess high surface areas (332-367 m 2/g), large pore volumes (0.66-0.78 cm 3/g), and large pore sizes (about 10.7 nm). The FT-IR analysis reveals almost complete elimination of triblock copolymer F127, and the maintenance of organic groups. This method shows potentials in removing templates from nanocomposites containing functional moieties.

CRADA Final Report For CRADA NO. CR-12-006 [Operation and Testing of an SO 2-depolarized Electrolyzer (SDE) for the Purpose of Hydrogen and Sulfuric Acid Production

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

Summers, W. A.; Colon-Mercado, H. R.; Steimke, J. L.

2014-02-24

Over the past several years, Savannah River National Laboratory (SRNL) has led a team of collaborators under the Department of Energy’s (DOE) nuclear hydrogen production program to develop the Hybrid Sulfur (HyS) Process. HyS is a 2-step water-splitting process consisting of high temperature decomposition of sulfuric acid to generate SO 2, followed by the electrolysis of aqueous SO 2 to generate hydrogen and sulfuric acid. The latter is fed back into the high temperature reactor. SRNL designed and built an SO 2-depolarized electrolyzer (SDE) and a test facility. Over 40 SDE’s were tested using different catalysts, membranes and other components.more » SRNL demonstrated that an SDE could be operated continuously for approximately 200 hours under certain conditions without buildup of sulfur at the SDE’s cathode, thus solving a key technical problem with SDE technology. Air Products and Chemicals, Inc. (APCI) is a major supplier of hydrogen production systems, and they have proprietary technology that could benefit from the SDE developed by SRNS, or some improved version thereof. However, to demonstrate that SRNL’s SDE is a truly viable approach to the electrolyzer design, continuous operation for far greater periods of time than 200 hours must be demonstrated, and the electrolyzer must be scaled up to greater hydrogen production capacities. SRNL and Air Products entered into a Cooperative Research and Development Agreement with the objective of demonstrating the effectiveness of the SDE for hydrogen and sulfuric acid production and to demonstrate long-term continuous operation so as to dramatically increase the confidence in the SDE design for commercial operation. SRNL prepared a detailed technical report documenting previous SDE development, including the current SDE design and operating conditions that led to the 200-hour sulfurfree testing. SRNL refurbished its single cell SDE test facility and qualified the equipment for continuous operation. A new

Separation of sulfur isotopes

DOEpatents

DeWitt, Robert; Jepson, Bernhart E.; Schwind, Roger A.

1976-06-22

Sulfur isotopes are continuously separated and enriched using a closed loop reflux system wherein sulfur dioxide (SO.sub.2) is reacted with sodium hydroxide (NaOH) or the like to form sodium hydrogen sulfite (NaHSO.sub.3). Heavier sulfur isotopes are preferentially attracted to the NaHSO.sub.3, and subsequently reacted with sulfuric acid (H.sub.2 SO.sub.4) forming sodium hydrogen sulfate (NaHSO.sub.4) and SO.sub.2 gas which contains increased concentrations of the heavier sulfur isotopes. This heavy isotope enriched SO.sub.2 gas is subsequently separated and the NaHSO.sub.4 is reacted with NaOH to form sodium sulfate (Na.sub.2 SO.sub.4) which is subsequently decomposed in an electrodialysis unit to form the NaOH and H.sub.2 SO.sub.4 components which are used in the aforesaid reactions thereby effecting sulfur isotope separation and enrichment without objectionable loss of feed materials.

Sulfur geochemistry of hydrothermal waters in Yellowstone National Park, Wyoming, USA. II. Formation and decomposition of thiosulfate and polythionate in Cinder Pool

NASA Astrophysics Data System (ADS)

Xu, Y.; Schoonen, M. A. A.; Nordstrom, D. K.; Cunningham, K. M.; Ball, J. W.

2000-04-01

thiosulfate and elemental sulfur; and (2) by disproportionation to sulfate and thiosulfate. This study demonstrates that the presence of a subaqueous molten sulfur pool and sulfur spherules in Cinder Pool is of importance in controlling the pathways of aqueous sulfur redox reactions. Some of the insights gained at Cinder Pool may be relevant to acid crater lakes where sulfur spherules are observed and variations in polythionate concentrations are used to monitor and predict volcanic activity.

Sulfur geochemistry of hydrothermal waters in Yellowstone National Park, Wyoming, USA. II. Formation and decomposition of thiosulfate and polythionate in Cinder Pool

USGS Publications Warehouse

Xu, Y.; Schoonen, M.A.A.; Nordstrom, D. Kirk; Cunningham, K.M.; Ball, J.W.

2000-01-01

, yielding thiosulfate and elemental sulfur; and (2) by disproportionation to sulfate and thiosulfate. This study demonstrates that the presence of a subaqueous molten sulfur pool and sulfur spherules in Cinder Pool is of importance in controlling the pathways of aqueous sulfur redox reactions. Some of the insights gained at Cinder Pool may be relevant to acid crater lakes where sulfur spherules are observed and variations in polythionate concentrations are used to monitor and predict volcanic activity.

Sulfur-Tolerant Molybdenum Carbide Catalysts Enabling Low-Temperature Stabilization of Fast Pyrolysis Bio-oil

DOE PAGES

Li, Zhenglong; Choi, Jae-Soon; Wang, Huamin; ...

2017-08-18

Low-temperature hydrogenation of carbonyl fractions can greatly improve the thermal stability of fast pyrolysis bio-oil which is crucial to achieve long-term operation of high-temperature upgrading reactors. The current state of the art, precious metals such as ruthenium, although highly effective in carbonyl hydrogenation, rapidly loses performance due to sulfur sensitivity. The present work showed that molybdenum carbides were active and sulfur-tolerant in low-temperature conversion carbonyl compounds. Furthermore, due to surface bifunctionality (presence of both metallic and acid sites), carbides catalyzed both C=O bond hydrogenation and C-C coupling reactions retaining most of carbon atoms in liquid products as more stable andmore » higher molecular weight oligomeric compounds while consuming less hydrogen than ruthenium. The carbides proved to be resistant to other deactivation mechanisms including hydrothermal aging, oxidation, coking and leaching. These properties enabled carbides to achieve and maintain good catalytic performance in both aqueous-phase furfural conversion and real bio-oil stabilization with sulfur present. This finding strongly suggests that molybdenum carbides can provide a catalyst solution necessary for the development of commercially viable bio-oil stabilization technology.« less

Sulfur-Tolerant Molybdenum Carbide Catalysts Enabling Low-Temperature Stabilization of Fast Pyrolysis Bio-oil

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

Li, Zhenglong; Choi, Jae-Soon; Wang, Huamin

Low-temperature hydrogenation of carbonyl fractions can greatly improve the thermal stability of fast pyrolysis bio-oil which is crucial to achieve long-term operation of high-temperature upgrading reactors. The current state of the art, precious metals such as ruthenium, although highly effective in carbonyl hydrogenation, rapidly loses performance due to sulfur sensitivity. The present work showed that molybdenum carbides were active and sulfur-tolerant in low-temperature conversion carbonyl compounds. Furthermore, due to surface bifunctionality (presence of both metallic and acid sites), carbides catalyzed both C=O bond hydrogenation and C-C coupling reactions retaining most of carbon atoms in liquid products as more stable andmore » higher molecular weight oligomeric compounds while consuming less hydrogen than ruthenium. The carbides proved to be resistant to other deactivation mechanisms including hydrothermal aging, oxidation, coking and leaching. These properties enabled carbides to achieve and maintain good catalytic performance in both aqueous-phase furfural conversion and real bio-oil stabilization with sulfur present. This finding strongly suggests that molybdenum carbides can provide a catalyst solution necessary for the development of commercially viable bio-oil stabilization technology.« less

Titanium leaching from red mud by diluted sulfuric acid at atmospheric pressure.

PubMed

Agatzini-Leonardou, S; Oustadakis, P; Tsakiridis, P E; Markopoulos, Ch

2008-09-15

Laboratory-scale research has focused on the recovery of titanium from red mud, which is obtained from bauxite during the Bayer process for alumina production. The leaching process is based on the extraction of this element with diluted sulfuric acid from red mud under atmospheric conditions and without using any preliminary treatment. Statistical design and analysis of experiments were used, in order to determine the main effects and interactions of the leaching process factors, which were: acid normality, temperature and solid to liquid ratio. The titanium recovery efficiency on the basis of red mud weight reached 64.5%. The characterization of the initial red mud, as well as this of the leached residues was carried out by X-ray diffraction, TG-DTA and scanning electron microscopy.

Efficacy of reducing sugar and phenol-sulfuric acid assays for analysis of soluble carbohydrates in feedstuffs

USDA-ARS?s Scientific Manuscript database

Reducing sugar (RSA) and phenol–sulfuric acid (PSA) assays are commonly used to analyze water-soluble carbohydrates. However, questions have arisen as to their accuracy for measurement of feedstuffs with diverse carbohydrate profiles. This study evaluated the efficacy of RSA and PSA as they would co...

Determination of sulfur trioxide in engine exhaust.

PubMed Central

Arnold, D R

1975-01-01

Sulfur trioxide in the exhaust gas of an internal combustion engine is removed and concentrated by absorption in a solution of 80% isopropyl alcohol, which quantitatively absorbs it and inhibits the oxidation of any sulfur dioxide which may be absorbed. The absorbed sulfur trioxide (sulfuric acid) is determined by an absorption titration by using barium chloride as the titrant and thorin as the indicator. The sulfur dioxide content of the exhaust is measured continuously by means of a DuPont Model 411 ultraviolet photoanalyzer. PMID:50930

Surface grafting of cellulose nanocrystals with poly(ethylene oxide) in aqueous media.

PubMed

Kloser, Elisabeth; Gray, Derek G

2010-08-17

Aqueous suspensions of poly(ethylene oxide)-grafted nanocrystalline cellulose (PEO-grafted NCC) were prepared in order to achieve steric instead of electrostatic stabilization. A two-step process was employed: in the first step NCC suspensions prepared by sulfuric acid hydrolysis were desulfated with sodium hydroxide, and in the second step the surfaces of the crystals were functionalized with epoxy-terminated poly(ethylene oxide) (PEO epoxide) under alkaline conditions. The PEO-grafted samples were analyzed by conductometric titration, ATR-IR, solid-state NMR, MALDI-TOF MS, SEC MALLS, and AFM. The covalent nature of the linkage was confirmed by weight increase and MALDI-TOF analysis. The PEO-grafted cellulose nanocrystals (CNCs) formed a stable colloidal suspension that remained well dispersed, while the desulfated nanoparticles aggregated and precipitated. Upon concentration of the PEO-grafted aqueous NCC suspension, a chiral nematic phase was observed.

Aqueous humour and ultraviolet radiation.

PubMed

Ringvold, A

1980-01-01

Studies on the ultraviolet ray absorption in the aqueous humour of rabbit, cat, monkey, guinea pig, and rat showed marked species differences. In the rabbit aqueous the ascorbic acid, the proteins, and some amino acids (tyrosine, phenylalanine, cystine, and tryptophane) are together responsible for the total absorption, and a very great part of it refers to the ascorbic acid content. Accordingly, species with significant amounts of ascorbic acid in the aqueous (monkey, rabbit, guinea pig) have a greater absorption capacity towards ultraviolet radiation than species (cat, rat) lacking this substance. This effect of the ascorbic acid may contribute in protecting the lens against the most biotoxic ultraviolet rays. It seems that the ascorbic acid concentration is highest in the aqueous of typical day animals and lowest in species being active in the dark, indicating a correlation between the aqueous' ascorbic acid level and the quantity of incident light on the eye. The possible significance of changed aqueous ultraviolet ray absorption in the pathogenesis of human cataract development is discussed.

Regeneration of an aqueous solution from an acid gas absorption process by matrix stripping

DOEpatents

Rochelle, Gary T [Austin, TX; Oyenekan, Babatunde A [Katy, TX

2011-03-08

Carbon dioxide and other acid gases are removed from gaseous streams using aqueous absorption and stripping processes. By replacing the conventional stripper used to regenerate the aqueous solvent and capture the acid gas with a matrix stripping configuration, less energy is consumed. The matrix stripping configuration uses two or more reboiled strippers at different pressures. The rich feed from the absorption equipment is split among the strippers, and partially regenerated solvent from the highest pressure stripper flows to the middle of sequentially lower pressure strippers in a "matrix" pattern. By selecting certain parameters of the matrix stripping configuration such that the total energy required by the strippers to achieve a desired percentage of acid gas removal from the gaseous stream is minimized, further energy savings can be realized.

Liquid Superlubricity of Polyethylene Glycol Aqueous Solution Achieved with Boric Acid Additive.

PubMed

Ge, Xiangyu; Li, Jinjin; Zhang, Chenhui; Luo, Jianbin

2018-03-27

Boric acid is a weak acid and has been used as a lubrication additive because of its special structure. In this study, we report that boric acid could achieve a robust superlubricity (μ < 0.01) as an additive in polyethylene glycol (PEG) aqueous solution at the Si 3 N 4 /SiO 2 interfaces. The superlow and steady friction coefficient of approximately 0.004-0.006 could be achieved with boric acid under neutral conditions (pH of approximately 6.4), which is different from the acidic conditions leading to superlubricity. The influence of various factors, including boric acid concentration, sliding speed, applied load, PEG molecular weight, and the volume of lubricant on the superlubricity, were investigated. The results reveal that the PEG aqueous solution with the boric acid additive could achieve superlubricity under a wide range of conditions. The surface composition analysis shows that the synergy effect between boric acid and PEG provides sufficient H + ions to realize the running-in process. Moreover, a composite tribochemical film composed of silica and ammonia-containing compounds were formed on the ball surface, contributing to the superlubricity. The film thickness calculation shows that superlubricity was achieved in a mixed lubrication region, and therefore, the superlubricity state was dominated by both the composite tribochemical film formed via the tribochemical reaction on the contact surfaces and the hydrodynamic lubricating film between the contact surfaces. Such a liquid superlubricity achieved under neutral conditions is of importance for both scientific understanding and engineering applications.

21 CFR 184.1095 - Sulfuric acid.

Code of Federal Regulations, 2011 CFR

2011-04-01

... CONSUMPTION (CONTINUED) DIRECT FOOD SUBSTANCES AFFIRMED AS GENERALLY RECOGNIZED AS SAFE Listing of Specific... (SO2) with oxygen and mixing the resultant sulfur trioxide (SO3) with water, or by reacting nitric...

21 CFR 184.1095 - Sulfuric acid.

Code of Federal Regulations, 2013 CFR

2013-04-01

... CONSUMPTION (CONTINUED) DIRECT FOOD SUBSTANCES AFFIRMED AS GENERALLY RECOGNIZED AS SAFE Listing of Specific... (SO2) with oxygen and mixing the resultant sulfur trioxide (SO3) with water, or by reacting nitric...

Simultaneous measurement of volatile sulfur compounds using ascorbic acid for oxidant removal and gas chromatography-flame photometric detection.

PubMed

Inomata, Y; Matsunaga, K; Murai, Y; Osada, K; Iwasaka, Y

1999-12-09

A method for the simultaneous measurement of volatile sulfur compounds (COS, H2S, CS2, CH3SH, DMS) is established with preconcentration and GC-flame photometric detection (FPD). Prior to preconcentration of ambient air, it was necessary to remove SO2, water vapor and atmospheric oxidant. SO2 and water vapor were removed using a glass fiber filter and a cooled PTFE water trap loop, respectively. In order to remove atmospheric oxidant, the efficiency of an ascorbic acid scrubber was examined. It was found that an ascorbic acid scrubber enabled measurement of volatile sulfur compounds without adsorption and reaction loss. The detection limits for COS, H2S, CS2, CH3SH and DMS were 20, 34, 35, 263 and 44 pg of S, respectively.

Sulfate Mineral Formation from Acid-Weathered Phyllosilicates: Implications for the Aqueous History of Mars

NASA Technical Reports Server (NTRS)

Craig, P. I.; Ming, D. W.; Rampe, E. B.; Morris, R. V.

2015-01-01

Phyllosilicates on Mars are thought to have formed under neutral to alkaline conditions during Mars' earliest Noachian geologic era (approx. 4.1-3.7 Gya). Sulfate formation, on the other hand, requires more acidic conditions which are thought to have occurred later during Mars' Hesperian era (approx. 3.7-3.0 Gya). Therefore, regions on Mars where phyllosilicates and sulfates are found in close proximity to each other provide evidence for the geologic and aqueous conditions during this global transition. Both phyllosilicates and sulfates form in the presence of water and thus give clues to the aqueous history of Mars and its potential for habitability. Phyllosilicates that formed during the Noachian era may have been weathered by the prevailing acidic conditions that characterize the Hesperian. Therefore, the purpose of this study is to characterize the alteration products resulting from acid-sulfate weathered phyllosilicates in laboratory experiments. This study focuses on two phyllosilicates commonly identified with sulfates on Mars: nontronite and saponite. We also compare our results to observations of phyllosilicates and sulfates on Mars to better understand the formation process of sulfates in close proximity to phyllosilicates on Mars and constrain the aqueous conditions of these regions on Mars.

Effective Removal of Tetracycline from Aqueous Solution by Organic Acid-Coated Magnetic Nanoparticles.

PubMed

Guo, Liang; Liang, Yuyan; Chen, Xuelan; Xu, Wei; Wu, Kesheng; Wei, Hua; Xiong, Yonghua

2016-03-01

Self-assembled iron oxide nanocomposites are good magnetic nano-adsorbents that can be prepared using simple methods. Four types of organic acid-functionalised (oleic acid, undecenoic acid, caprylic acid or hexanoic acid) magnetic nanoparticles (MNPs) were synthesised through a one-pot chemisorption method for the removal of tetracycline (TC) from aqueous solution. The undecenoic acid-coated MNPs (UA-MNPs) exhibited the highest adsorption efficiency and can be easily retrieved with a low-gradient magnetic separator (0.4 Tesla) at pH 5.0 aqueous solution. The TC adsorption process on the UA-MNPs followed the Langmuir isotherm and the maximum adsorption capacities increased from 86.96 mg g(-1) to 222.2 mg g(-1) with the increase in temperature from 288 K to 318 K. The kinetics of adsorption fits pseudo-second-order model perfectly with a rate constant, 5.946 g mg(-1) min(-1) at 298 K. The positive values of the enthalpy (AH) and the negative value of the free energy (AG) indicated an endothermic and spontaneous adsorption process of TC on the UA-MNPs. Moreover, the UA-MNPs possessed excellent ability to adsorb the other three major types of TC antibiotics, including chlortetracycline, oxytetracycline and doxycycline.

Adsorption of Copper Ion using Acrylic Acid-g-Polyaniline in Aqueous Solution

NASA Astrophysics Data System (ADS)

Kamarudin, Sabariah; Mohammad, Masita

2018-04-01

A conductive polymer, polyaniline (PANI) has unique electrical behaviour, stable in the environment, easy synthesis and have wide application in various fields. Modification of PANI in order to improve its adsorption capacity has been done. In this study, the polyaniline-grafted acrylic acid has been prepared and followed by adsorption of copper ion in aqueous solution. Acrylic acid, PANI and acrylic acid-g-polyaniline (Aag-PANI) were characterized by FTIR and SEM to determine its characteristic. The adsorption capacity was investigated to study the removal capacity of Cu ion from aqueous solution. Two parameters were selected which are pH (2, 4 and 6) and initial metal ion concentration (50 mg/L, 100 mg/L and 200 mg/L). The maximum adsorption capacity for PANI and Aag-PANI are 1.7 mg/g and 64.6 mg/g, respectively, at an initial concentration of 100 mg/L. The Langmuir adsorption isotherm model and Freundlich adsorption isotherm model have been used and showed that it is heterolayer adsorption by follows the Freundlich isotherm model.

Thermodynamic Analysis of the Cu-As-S-(O) System Relevant to Sulfuric Acid Baking of Enargite at 473 K (200 °C)

NASA Astrophysics Data System (ADS)

Safarzadeh, M. Sadegh; Miller, Jan D.; Huang, Hsin H.

2014-04-01

While the growing demand for copper has compelled the industry to adapt new technologies for the treatment of copper-arsenic (enargite) concentrates, the refractory nature of such concentrates combined with the troublesome presence of arsenic has created a major metallurgical and environmental challenge. Preliminary results of the acid bake-leach process at the University of Utah have shown some potential advantages for the treatment of enargite concentrates. While the transformation of enargite to copper sulfate, arsenolite, and elemental sulfur has already been established experimentally, thermodynamic evaluation of the sulfuric acid baking process provides further understanding which should be useful. In this article, the available thermodynamic data for the species involved in the Cu-As-S-O system are compiled. These data were used to calculate the phase stability (Kellogg) diagrams as well as equilibrium compositions at 473 K (200 °C) using the STABCAL and HSC Chemistry® 5.1 software packages. The equilibrium composition calculations indicate that enargite can transform to copper sulfate either directly or through chalcocite and/or covellite. The major gaseous species during baking were found to be SO2 and H2O. The results of the thermodynamic calculations were further compared with two confirmatory baking experiments involving a high-quality enargite sample. The condensed reaction products from sulfuric acid baking based on XRD results include CuSO4, As2O3, CuO·CuSO4, and S8 under both neutral and oxidative conditions. While all these compounds were predicted through equilibrium calculations, some of the predicted compounds were not detected in the sulfuric acid-baked enargite. None of the calculations indicated any appreciable amounts of arsenic-bearing gases at the baking temperature of 473 K (200 °C). Consistent with thermodynamic predictions, no H2S gas was detected during the sulfuric acid baking experiment. Approximately, 80 pct of the baked

Crystallization of aqueous inorganic-malonic acid particles: nucleation rates, dependence on size, and dependence on the ammonium-to-sulfate ratio.

PubMed

Parsons, Matthew T; Riffell, Jenna L; Bertram, Allan K

2006-07-06

Using an electrodynamic balance, we determined the relative humidity (RH) at which aqueous inorganic-malonic acid particles crystallized, with ammonium sulfate ((NH(4))(2)SO(4)), letovicite ((NH(4))(3)H(SO(4))(2)), or ammonium bisulfate (NH(4)HSO(4)) as the inorganic component. The results for (NH(4))(2)SO(4)-malonic acid particles and (NH(4))(3)H(SO(4))(2)-malonic acid particles show that malonic acid decreases the crystallization RH of the inorganic particles by less than 7% RH when the dry malonic acid mole fraction is less than 0.25. At a dry malonic acid mole fraction of about 0.5, the presence of malonic acid can decrease the crystallization RH of the inorganic particles by up to 35% RH. For the NH(4)HSO(4)-malonic acid particles, the presence of malonic acid does not significantly modify the crystallization RH of the inorganic particles for the entire range of dry malonic acid mole fractions studied; in all cases, either the particles did not crystallize or the crystallization RH was close to 0% RH. Size dependent measurements show that the crystallization RH of aqueous (NH(4))(2)SO(4) particles is not a strong function of particle volume. However, for aqueous (NH(4))(2)SO(4)-malonic acid particles (with dry malonic acid mole fraction = 0.36), the crystallization RH is a stronger function of particle volume, with the crystallization RH decreasing by 6 +/- 3% RH when the particle volume decreases by an order of magnitude. To our knowledge, these are the first size dependent measurements of the crystallization RH of atmospherically relevant inorganic-organic particles. These results suggest that for certain organic mole fractions the particle size and observation time need to be considered when extrapolating laboratory crystallization results to atmospheric scenarios. For aqueous (NH(4))(2)SO(4) particles, the homogeneous nucleation rate data are a strong function of RH, but for aqueous (NH(4))(2)SO(4)-malonic acid particles (with dry organic mole fraction = 0

Recovery of acetic acid from dilute aqueous solutions using catalytic dehydrative esterification with ethanol.

PubMed

Yagyu, Daisuke; Ohishi, Tetsuo; Igarashi, Takeshi; Okumura, Yoshikuni; Nakajo, Tetsuo; Mori, Yuichiro; Kobayashi, Shū

2013-03-01

We have developed a direct esterification of aqueous acetic acid with ethanol (molar ratio=1:1) catalyzed by polystyrene-supported or homogeneous sulfonic acids toward the recovery of acetic acid from wastewater in chemical plants. The equilibrium yield was significantly increased by the addition of toluene, which had a high ability to extract ethyl acetate from the aqueous phase. It was shown that low-loading and alkylated polystyrene-supported sulfonic acid efficiently accelerated the reaction. These results suggest that the construction of hydrophobic reaction environments in water was critical in improving the chemical yield. Addition of inorganic salts was also effective for the reaction under not only biphasic conditions (toluene-water) but also toluene-free conditions, because the mutual solubility of ethyl acetate and water was suppressed by the salting-out effect. Among the tested salts, CaCl(2) was found to be the most suitable for this reaction system. Copyright © 2012 Elsevier Ltd. All rights reserved.

Ambient Air Monitoring for Sulfur Compounds

ERIC Educational Resources Information Center

Forrest, Joseph; Newman, Leonard

1973-01-01

A literature review of analytical techniques available for the study of compounds at low concentrations points up some of the areas where further research is needed. Compounds reviewed are sulfur dioxide, sulfuric acid, ammonium sulfate and bisulfate, metal sulfates, hydrogen sulfide, and organic sulfides. (BL)

Surface Crystallographic Dependence of Voltammetric Oxidation of Polyhydric Alcohols and Related Systems at Monocrystalline Gold-Acidic Aqueous Interfaces

DTIC Science & Technology

1992-02-01

Crystallographic Dependence of Voltaumetric Oxidation of Polyhydric Alcohols and Related Systems at Monocrystalline Gold -Acidic Aqueous Interfaces by...Crystallographic Dependence of Voltamnnetric Oxidation )f Polyhydric Alcohols and Related Systems at onocrystalline Gold -Acidic Aqueous [nterfaces...mannitol, on seven oriented gold surfaces, Au(lll), 100), (110), (221), (533), (311), and (210), is reported with the objective of assessing the ole of

Rosmarinic acid content in antidiabetic aqueous extract of Ocimum canum Sims grown in Ghana

USDA-ARS?s Scientific Manuscript database

Rosmarinic acid (RA) is an important polyphenol that is found in a variety of herbs including Ocimum canum sims (locally called eme or akokobesa in Ghana). Aqueous extracts from the leaves of O.canum are used as an antidiabetic herbal medicine in Ghana. Interestingly, rosmarinic acid content and p...

A GC-ECD method for estimation of free and bound amino acids, gamma-aminobutyric acid, salicylic acid, and acetyl salicylic acid from Solanum lycopersicum (L.).

PubMed

Meher, Hari Charan; Gajbhiye, Vijay T; Singh, Ghanendra

2011-01-01

A gas chromatograph with electron capture detection method for estimation of selected metabolites--amino acids (free and bound), gamma-aminobutyric acid (GABA), salicylic acid (SA), and acetyl salicylic acid (ASA) from tomato--is reported. The method is based on nitrophenylation of the metabolites by 1-fluoro-2, 4-dinitrobenzene under aqueous alkaline conditions to form dinitophenyl derivatives. The derivatives were stable under the operating conditions of GC. Analysis of bound amino acids comprised perchloric acid precipitation of protein, alkylation (carboxymethylation) with iodoacetic acid, vapor-phase hydrolysis, and derivatization with 1-fluoro-2,4-dinitrobenzene in that order. The metabolites were resolved in 35 min, using a temperature-programmed run. The method is rapid, sensitive, and precise. It easily measured the typical amino acids (aspartate, asparagine, glutamate, glutamine, alanine, leucine, lysine, and phenylalanine) used for identification and quantification of a protein, resolved amino acids of the same mass (leucine and isoleucine), satisfactorily measured sulfur amino acid (methionine, cystine, and cysteine), and quantified GABA, SA, and ASA, as well. The developed method was validated for specificity, linearity, and precision. It has been applied and recommended for estimation of 25 metabolites from Solanum lycopersicum (L.).

Effect of temperature on iron leaching from bauxite residue by sulfuric acid.

PubMed

Liu, Zhi-Rong; Zeng, Kai; Zhao, Wei; Li, Ying

2009-01-01

Bauxite residue, as solid waste from alumina production, contains mainly hematite [Fe2O3]. Kinetic study of iron leaching of bauxite residue by diluted sulfuric acid at atmospheric pressure has been investigated. The results have been obtained as following: (i) Temperature play an important role in iron leaching from bauxite residue. Higher temperature is favor of Fe(III) leaching from bauxite residue. (ii) The leaching process is applicable to the intra-particle diffusion model and the apparent activation energy of model of leaching is found to be 17.32 kJ/mol.

SURFACE REACTIONS OF OXIDES OF SULFUR

EPA Science Inventory

Surface reactions of several sulfur-containing molecules have been studied in order to understand the mechanism by which sulfate ions are formed on atmospheric aerosols. At 25C the heterogeneous oxidation of SO2 by NO2 to sulfuric acid and sulfate ions occurred on hydrated silica...

Novel aqueous dual-channel aluminum-hydrogen peroxide battery

NASA Astrophysics Data System (ADS)

Marsh, Catherine; Licht, Stuart

1994-06-01

A dual-channel aluminum hydrogen peroxide battery is introduced with an open-circuit voltage of 1.9 volts, polarization losses of 0.9 mV cm(exp 2) mA(exp -1), and power densities of 1 W/cm(exp 2). Catholyte and anolyte cell compartments are separated by an Ir/Pd modified porous nickel cathode. Separation of catholyte and anolyte chambers prevents hydrogen peroxide poisoning of the aluminum anode. The battery is expressed by aluminum oxidation and aqueous solution phase hydrogen peroxide reduction for an overall battery discharge consisting of 2Al + 3H2O2 + 2OH(-) yields 2AlO2(-) + 4H2O E = 2.3 V. The search for electrical propulsion sources which fit the requirements for electrically powered vehicles has blurred the standard characteristics associated with electrochemical storage systems. Presently, electrochemical systems comprised of mechanically rechargeable primary batteries, secondary batteries, and fuel cells are candidates for electrochemical propulsion sources. While important advances in energy and power density continue for nonaqueous and molten electrolytes, aqueous electrolyte batteries often have an advantage in simplicity, conductivity, cost effectiveness, and environmental impact. Systems coupling aluminum anodes and aqueous electrolytes have been investigated. These systems include: aluminum/silver oxide, aluminum/manganese dioxide, aluminum air, aluminum/hydrogen peroxide aqueous batteries, and the recently introduced aluminum/ferricyanide and aluminum sulfur aqueous batteries. Conventional aqueous systems such as the nickel cadmium and lead-acid batteries are characterized by their relatively low energy densities and adverse environmental impact. Other systems have substantially higher theoretical energy capacities. While aluminum-silver oxide has demonstrated the highest steady-state power density, its high cost is an impediment for widespread utilization for electric propulsion.

EMISSIONS OF SULFUR TRIOXIDE FROM COAL-FIRED POWER PLANTS

EPA Science Inventory

Emissions of sulfur trioxide (SO3) are a key component of plume opacity and acid deposition. Consequently, these emissions need to be low enough not to cause opacity violations and acid deposition. Generally, a small fraction of sulfur in coal is converted to SO3 in coal-fired co...

Economic, Environmental, and Coal Market Impacts of Sulfur Dioxide Emissions Trading under Alternative Acid Rain Control Proposals (1989)

EPA Pesticide Factsheets

This report examines the ramifications of diferent levels of emissions trading in the context of tro representative electric utility sulfur dioxide emisson reduction proposals designed to control acid rain, and in the absence of any new control program.

Sulfur Earth

NASA Astrophysics Data System (ADS)

de Jong, B. H.

2007-12-01

Variations in surface tension affect the buoyancy of objects floating in a liquid. Thus an object floating in water will sink deeper in the presence of dishwater fluid. This is a very minor but measurable effect. It causes for instance ducks to drown in aqueous solutions with added surfactant. The surface tension of liquid iron is very strongly affected by the presence of sulfur which acts as a surfactant in this system varying between 1.9 and 0.4 N/m at 10 mass percent Sulfur (Lee & Morita (2002), This last value is inferred to be the maximum value for Sulfur inferred to be present in the liquid outer core. Venting of Sulfur from the liquid core manifests itself on the Earth surface by the 105 to 106 ton of sulfur vented into the atmosphere annually (Wedepohl, 1984). Inspection of surface Sulfur emission indicates that venting is non-homogeneously distributed over the Earth's surface. The implication of such large variation in surface tension in the liquid outer core are that at locally low Sulfur concentration, the liquid outer core does not wet the predominantly MgSiO3 matrix with which it is in contact. However at a local high in Sulfur, the liquid outer core wets this matrix which in the fluid state has a surface tension of 0.4 N/m (Bansal & Doremus, 1986), couples with it, and causes it to sink. This differential and diapiric movement is transmitted through the essentially brittle mantle (1024 Pa.s, Lambeck & Johnson, 1998; the maximum value for ice being about 1030 Pa.s at 0 K, in all likely hood representing an upper bound of viscosity for all materials) and manifests itself on the surface by the roughly 20 km differentiation, about 0.1 % of the total mantle thickness, between topographical heights and lows with concomitant lateral movement in the crust and upper mantle resulting in thin skin tectonics. The brittle nature of the medium though which this movement is transmitted suggests that the extremes in topography of the D" layer are similar in range to

Composition and process for separating cesium ions from an acidic aqueous solution also containing other ions

DOEpatents

Dietz, Mark L.; Horwitz, E. Philip; Bartsch, Richard A.; Barrans, Jr., Richard E.; Rausch, David

1999-01-01

A crown ether cesium ion extractant is disclosed as is its synthesis. The crown ether cesium ion extractant is useful for the selective purification of cesium ions from aqueous acidic media, and more particularly useful for the isolation of radioactive cesium-137 from nuclear waste streams. Processes for isolating cesium ions from aqueous acidic media using the crown ether cesium extractant are disclosed as are processes for recycling the crown ether cesium extractant and processes for recovering cesium from a crown ether cesium extractant solution.

Composition and process for separating cesium ions from an acidic aqueous solution also containing other ions

DOEpatents

Dietz, M.L.; Horwitz, E.P.; Bartsch, R.A.; Barrans, R.E. Jr.; Rausch, D.

1999-03-30

A crown ether cesium ion extractant is disclosed as is its synthesis. The crown ether cesium ion extractant is useful for the selective purification of cesium ions from aqueous acidic media, and more particularly useful for the isolation of radioactive cesium-137 from nuclear waste streams. Processes for isolating cesium ions from aqueous acidic media using the crown ether cesium extractant are disclosed as are processes for recycling the crown ether cesium extractant and processes for recovering cesium from a crown ether cesium extractant solution. 4 figs.

Hydrolytic cleavage of pyroglutamyl-peptide bond. V. selective removal of pyroglutamic acid from biologically active pyroglutamylpeptides in high concentrations of aqueous methanesulfonic acid.

PubMed

Kobayashi, Junko; Ohki, Kazuhiro; Okimura, Keiko; Hashimoto, Tadashi; Sakura, Naoki

2006-06-01

Application of aqueous methanesulfonic acid (MSA) for selective chemical removal of pyroglutamic acid (pGlu) residue from five biologically active pyroglutamyl-peptides (pGlu-X-peptides, X=amino acid residue at position 2) was examined. Gonadotropin releasing hormone (Gn-RH), dog neuromedin U-8 (d-NMU-8), physalaemin (PH), a bradykinin potentiating peptide (BPP-5a) and neurotensin (NT) as pGlu-X-peptides were incubated in either 70% or 90% aqueous MSA at 25 degrees C. HPLC analysis of the incubation solutions showed that the main decomposition product was H-X-peptide derived from each pGlu-X-peptide by the removal of pGlu. The results revealed that the pGlu-X peptide bond had higher susceptibility than various internal amide bonds in the five peptides examined, including the Trp-Ser bond in Gn-RH, the C-terminal Asn-NH(2) in d-NMU-8, and the Asp-Pro bond in PH, whose acid susceptibility is well known. Thus, mild hydrolysis with high concentrations of aqueous MSA may be applicable to chemically selective removal of pGlu from pGlu-X-peptides for structural examinations.

Studies on the protein and sulfur amino acid requirements of young bobwhite quail

USGS Publications Warehouse

Serafin, J.A.

1977-01-01

Four experiments were conducted with purified diets to examine the influence of protein level and to estimate the sulfur amino acid (S.A.A.) requirement of young Bobwhite quail (Colinus virginianus). These studies demonstrated (I) that 26% protein was sufficient for rapid growth when the diet was supplemented with methionine; (2) that diets containing higher levels of protein (29.3% and 31.3%) failed to support satisfactory growth unless they contained supplemental methionine; and (3) that young Bobwhite quail require no more than 1.0% sulfur-containing amino acids for optimal growth and efficiency of feed utilization. A fifth experiment was conducted to examine the protein and S.A.A. requirements of young Bobwhite quail using practical rations and to compare results with those obtained with purified diets. Diets containing 24%, 26% and 28% protein were supplied with and without supplemental methionine in a five week study. Results showed significant growth responses to protein and supplemental methionine. Responses showed that Bobwhite quail require no more than 26% protein for maximum growth and efficiency of feed utilization when the S.A.A. level of the diet was approximately 1.0%. The results were in close agreement with those obtained with purified diets. These findings define more precisely than had been known the quantitative requirements of young Bobwhite quail for protein and for the S.A.A. necessary for optimal growth.

In vivo contribution of amino acid sulfur to cartilage proteoglycan sulfation

PubMed Central

Pecora, Fabio; Gualeni, Benedetta; Forlino, Antonella; Superti-Furga, Andrea; Tenni, Ruggero; Cetta, Giuseppe; Rossi, Antonio

2006-01-01

Cytoplasmic sulfate for sulfation reactions may be derived either from extracellular fluids or from catabolism of sulfur-containing amino acids and other thiols. In vitro studies have pointed out the potential relevance of sulfur-containing amino acids as sources for sulfation when extracellular sulfate concentration is low or when its transport is impaired such as in DTDST [DTD (diastrophic dysplasia) sulfate transporter] chondrodysplasias. In the present study, we have considered the contribution of cysteine and cysteine derivatives to in vivo macromolecular sulfation of cartilage by using the mouse model of DTD we have recently generated [Forlino, Piazza, Tiveron, Della Torre, Tatangelo, Bonafe, Gualeni, Romano, Pecora, Superti-Furga et al. (2005) Hum. Mol. Genet. 14, 859–871]. By intraperitoneal injection of [35S]cysteine in wild-type and mutant mice and determination of the specific activity of the chondroitin 4-sulfated disaccharide in cartilage, we demonstrated that the pathway by which sulfate is recruited from the intracellular oxidation of thiols is active in vivo. To check whether cysteine derivatives play a role, sulfation of cartilage proteoglycans was measured after treatment for 1 week of newborn mutant and wild-type mice with hypodermic NAC (N-acetyl-L-cysteine). The relative amount of sulfated disaccharides increased in mutant mice treated with NAC compared with the placebo group, indicating an increase in proteoglycan sulfation due to NAC catabolism, although pharmacokinetic studies demonstrated that the drug was rapidly removed from the bloodstream. In conclusion, cysteine contribution to cartilage proteoglycan sulfation in vivo is minimal under physiological conditions even if extracellular sulfate availability is low; however, the contribution of thiols to sulfation becomes significant by increasing their plasma concentration. PMID:16719839

49 CFR 173.195 - Hydrogen cyanide, anhydrous, stabilized (hydrocyanic acid, aqueous solution).

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 2 2013-10-01 2013-10-01 false Hydrogen cyanide, anhydrous, stabilized... Hazardous Materials Other Than Class 1 and Class 7 § 173.195 Hydrogen cyanide, anhydrous, stabilized (hydrocyanic acid, aqueous solution). (a) Hydrogen cyanide, anhydrous, stabilized, must be packed in...

49 CFR 173.195 - Hydrogen cyanide, anhydrous, stabilized (hydrocyanic acid, aqueous solution).

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 2 2011-10-01 2011-10-01 false Hydrogen cyanide, anhydrous, stabilized... Hazardous Materials Other Than Class 1 and Class 7 § 173.195 Hydrogen cyanide, anhydrous, stabilized (hydrocyanic acid, aqueous solution). (a) Hydrogen cyanide, anhydrous, stabilized, must be packed in...

49 CFR 173.195 - Hydrogen cyanide, anhydrous, stabilized (hydrocyanic acid, aqueous solution).

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Hydrogen cyanide, anhydrous, stabilized... Hazardous Materials Other Than Class 1 and Class 7 § 173.195 Hydrogen cyanide, anhydrous, stabilized (hydrocyanic acid, aqueous solution). (a) Hydrogen cyanide, anhydrous, stabilized, must be packed in...

49 CFR 173.195 - Hydrogen cyanide, anhydrous, stabilized (hydrocyanic acid, aqueous solution).

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 2 2012-10-01 2012-10-01 false Hydrogen cyanide, anhydrous, stabilized... Hazardous Materials Other Than Class 1 and Class 7 § 173.195 Hydrogen cyanide, anhydrous, stabilized (hydrocyanic acid, aqueous solution). (a) Hydrogen cyanide, anhydrous, stabilized, must be packed in...

49 CFR 173.195 - Hydrogen cyanide, anhydrous, stabilized (hydrocyanic acid, aqueous solution).

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 2 2014-10-01 2014-10-01 false Hydrogen cyanide, anhydrous, stabilized... Hazardous Materials Other Than Class 1 and Class 7 § 173.195 Hydrogen cyanide, anhydrous, stabilized (hydrocyanic acid, aqueous solution). (a) Hydrogen cyanide, anhydrous, stabilized, must be packed in...

Gas chromatography/isotope ratio mass spectrometry: analysis of methanol, ethanol and acetic acid by direct injection of aqueous alcoholic and acetic acid samples.

PubMed

Ai, Guomin; Sun, Tong; Dong, Xiuzhu

2014-08-15

Methanol, ethanol, and acetic acid are not easily extracted from aqueous samples and are susceptible to isotope fractionation in gas chromatography/isotope ratio mass spectrometry (GC/IRMS) analysis. Developing a direct dilution GC/IRMS method for aqueous samples, by adjusting the sample concentrations in common solvents to be similar to each other and using a fixed GC split ratio, is very convenient and important because any linearity effects caused by amount-dependent isotope fractionation can be avoided. The suitability of acetonitrile and acetone solvents for the GC/IRMS analysis of pure methanol, ethanol and acetic acid, and commercial liquor and vinegar samples was evaluated using n-hexane and water as control solvents. All the solvents including water were separated from the analyte on a HP-INNOWAX column and were diverted away from the combustion interface. The influence of liquor matrix on the ethanol GC/IRMS analyses was evaluated by adding pure ethanol to liquor samples. Acetonitrile and acetone gave similar δ(13) C values for pure ethanol and pure acetic acid to those obtained in water and n-hexane, and also gave similar δ(13) C values of ethanol in liquor and acetic acid in white vinegar to that obtained in water. For methanol analysis, acetonitrile and refined acetone gave similar δ(13) C values to that obtained in water, but n-hexane was not a suitable solvent. In addition, isotopic fractionation caused by solvent and solute interactions was observed. We recommend using acetonitrile for the GC/IRMS analysis of aqueous alcoholic samples, and acetone for the analysis of aqueous acetic acid samples. This direct dilution method can provide high accurate and precise GC/IRMS analysis of the relative changes in δ(13) C values of methanol, ethanol, and acetic acid. Copyright © 2014 John Wiley & Sons, Ltd.

Influence of microwaves on the leaching kinetics of uraninite from a low grade ore in dilute sulfuric acid.

PubMed

Madakkaruppan, V; Pius, Anitha; T, Sreenivas; Giri, Nitai; Sarbajna, Chanchal

2016-08-05

This paper describes a study on microwave assisted leaching of uranium from a low-grade ore of Indian origin. The host rock for uranium mineralization is chlorite-biotite-muscovite-quartzo-feldspathic schist. The dominant presence of siliceous minerals determined leaching of uranium values in sulfuric acid medium under oxidizing conditions. Process parametric studies like the effect of sulfuric acid concentration (0.12-0.50M), redox potential (400-500mV), particle size (600-300μm) and temperature (35°-95°C) indicated that microwave assisted leaching is more efficient in terms of overall uranium dissolution, kinetics and provide relatively less impurities (Si, Al, Mg and Fe) in the leach liquor compared to conventional conductive leaching. The kinetics of leaching followed shrinking core model with product layer diffusion as controlling mechanism. Copyright © 2016 Elsevier B.V. All rights reserved.

Engine Tests Using High-Sulfur Diesel Fuel

DTIC Science & Technology

1980-09-01

0.5 wt% sulfur because "too high a sulfur content results in excessive cylinder wear due to acid build-up in the lubricating oil" (Ref 1). Previous...that the addition of 0.3 vol% of an organo-zinc complex fuel additive (zinc naphthenate ) to high-sulfur diesel fuel was an effective means of...disulfide. Addition of 0.3 vol% zinc naphthenate to high- sulfur fuel increased the fuel ash to 0.035 wt% while the cetane number re- mained unchanged

TiO2 activation using acid-treated vermiculite as a support: Characteristics and photoreactivity

NASA Astrophysics Data System (ADS)

Jin, Ling; Dai, Bin

2012-02-01

Vermiculite was treated by sulfuric or nitric acid aqueous solutions with different concentration. These modified materials as the promising supports, were used to immobilize TiO2. TiO2 was prepared by the precursor, which was obtained by substituting partly isopropyl alcohol with Cl- in titanium chloride {[Ti(IV)(OR)nClm] (n = 2-3, m = 4 - n)}. The TiO2/vermiculite composites were characterized by X-ray diffraction, scanning electron microscopy, and the nitrogen absorption. Their photocatalytic activity was evaluated by removal of methylene blue (MB). The pure anatase type crystalline phase was well deposited on the supports. The concentrations of acid for treatment had a significant influence on pore sizes and surface area of vermiculite. The treatment process changed microstructure of vermiculite, modified its characteristics, and farther improved the catalytic activity and absorption capacity of TiO2/vermiculite composites. The treatment effect of nitric acid was superior to that of sulfuric acid.

Aerobic sulfur-oxidizing bacteria: Environmental selection and diversification

NASA Technical Reports Server (NTRS)

Caldwell, D.

1985-01-01

Sulfur-oxidizing bacteria oxidize reduced inorganic compounds to sulfuric acid. Lithotrophic sulfur oxidizer use the energy obtained from oxidation for microbial growth. Heterotrophic sulfur oxidizers obtain energy from the oxidation of organic compounds. In sulfur-oxidizing mixotrophs energy are derived either from the oxidation of inorganic or organic compounds. Sulfur-oxidizing bacteria are usually located within the sulfide/oxygen interfaces of springs, sediments, soil microenvironments, and the hypolimnion. Colonization of the interface is necessary since sulfide auto-oxidizes and because both oxygen and sulfide are needed for growth. The environmental stresses associated with the colonization of these interfaces resulted in the evolution of morphologically diverse and unique aerobic sulfur oxidizers.

Water and Temperature Stresses Impact Canola (Brassica napus L.) Fatty Acid, Protein, and Yield over Nitrogen and Sulfur.

PubMed

Hammac, W Ashley; Maaz, Tai M; Koenig, Richard T; Burke, Ian C; Pan, William L

2017-12-06

Interactive effects of weather and soil nutrient status often control crop productivity. An experiment was conducted to determine effects of nitrogen (N) and sulfur (S) fertilizer rate, soil water, and atmospheric temperature on canola (Brassica napus L.) fatty acid (FA), total oil, protein, and grain yield. Nitrogen and sulfur were assessed in a 4-yr study with two locations, five N rates (0, 45, 90, 135, and 180 kg ha -1 ), and two S rates (0 and 17 kg ha -1 ). Water and temperature were assessed using variability across 12 site-years of dryland canola production. Effects of N and S were inconsistent. Unsaturated FA, oleic acid, grain oil, protein, and theoretical maximum grain yield were highly related to water and temperature variability across the site-years. A nonlinear model identified water and temperature conditions that enabled production of maximum unsaturated FA content, oleic acid content, total oil, protein, and theoretical maximum grain yield. Water and temperature variability played a larger role than soil nutrient status on canola grain constituents and yield.

Dilute sulfuric acid fractionation of Korean food waste for ethanol and lactic acid production by yeast.

PubMed

Kim, Yong Seon; Jang, Ji Yeon; Park, Seong Jik; Um, Byung Hwan

2018-04-01

Fermentation of food waste biomass can be used to produce biochemicals such as lactic acid and ethanol in a cost-effective manner. Korean food waste (KFW) dewatered by a screw press contains 23.1% glucan on a dry basis and is a potential raw material for the production of ethanol and lactic acid through fermentation. This study was conducted to optimize the dilute acid fractionation conditions for KFW fermentation with respect to the H 2 SO 4 concentration (0-0.8% w/v), temperature (130-190 °C), and residence time (1-128 min) using response surface methodology. Dilute sulfuric acid fractionation was carried out using a 30-mL stainless steel reactor under conditions, and then the dilute acid fractionation was scaled-up in 1-L and 7-L stainless steel reactors under the optimal conditions. The hydrolysate was concentrated, liquid-liquid extracted and neutralized for lactic acid and ethanol production. The highest concentration of glucose obtained from the KFW was 26.4 g/L using fractionation with 0.37% w/v H 2 SO 4 at 156 °C for 123.6 min. Using recombinant Saccharomyces cerevisiae containing a codon-optimized lactate dehydrogenase, the yield of lactic acid and ethanol was 77% of the theoretical yield for 17.4 g/L of fermentable sugar at pH 5.5. Additionally, the yield of ethanol produced by Issatchenkia orientalis was 89% of the theoretical yield for 25 g/L of fermentable sugar at pH 3. Copyright © 2018 Elsevier Ltd. All rights reserved.

Environmental Processing of Lipids Driven by Aqueous Photochemistry of α-Keto Acids

PubMed Central

2018-01-01

Sunlight can initiate photochemical reactions of organic molecules though direct photolysis, photosensitization, and indirect processes, often leading to complex radical chemistry that can increase molecular complexity in the environment. α-Keto acids act as photoinitiators for organic species that are not themselves photoactive. Here, we demonstrate this capability through the reaction of two α-keto acids, pyruvic acid and 2-oxooctanoic acid, with a series of fatty acids and fatty alcohols. We show for five different cases that a cross-product between the photoinitiated α-keto acid and non-photoactive species is formed during photolysis in aqueous solution. Fatty acids and alcohols are relatively unreactive species, which suggests that α-keto acids are able to act as radical initiators for many atmospherically relevant molecules found in the sea surface microlayer and on atmospheric aerosol particles. PMID:29806009

Assessing Potential Acidification of Marine Archaeological Wood Based on Concentration of Sulfur Species

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

Not Available

The presence of sulfur in marine archaeological wood presents a challenge to conservation. Upon exposure to oxygen, sulfur compounds in waterlogged wooden artifacts are being oxidized, producing sulfuric acid. This speeds the degradation of the wood, potentially damaging specimens beyond repair. Sulfur K-edge x-ray absorption spectroscopy was used to identify the species of sulfur present in samples from the timbers of the Mary Rose, a preserved 16th century warship known to undergo degradation through acidification. The results presented here show that sulfur content varied significantly on a local scale. Only certain species of sulfur have the potential to produce sulfuricmore » acid by contact with oxygen and seawater in situ, such as iron sulfides and elemental sulfur. Organic sulfurs, such as the amino acids cysteine and methionine, may produce acid but are integral parts of the wood's structure and may not be released from the organic matrix. The sulfur species contained in the sample reflect the exposure to oxygen while submerged, and this exposure can differ greatly over time and position. A better understanding of the species pathway to acidifications required, along with its location, in order to suggest a more customized and effective preservation strategy. Waterlogged archaeological wood, frequently in the form of shipwrecks, is being excavated for historical purposes in many countries around the world. Even after extensive efforts towards preservation, scientists are discovering that accumulation of sulfate salts results in acidic conditions on the surfaces of the artifacts. Sulfuric acid degrades structural fibers in the wood by acid hydrolysis of cellulose, accelerating the decomposition of the ship timbers. Determining the sulfur content of waterlogged wood is now of great importance in maritime archaeology. Artifact preservation is often more time consuming and expensive than the original excavation; but it is key to the availability of objects

Enhanced acid rain and atmospheric deposition of nitrogen, sulfur and heavy metals in Northern China

NASA Astrophysics Data System (ADS)

Pan, Y.; Wang, Y.

2013-12-01

Atmospheric deposition is known to be important mechanism reducing air pollution. In response to the growing concern on the potential effects of the deposited material entering terrestrial and aquatic environments as well as their subsequent health effects, since 2007 we have established a 10-site monitoring network in Northern China, where particularly susceptible to severe air pollution. Wet and dry deposition was collected using an automatic wet-dry sampler. The presentation will focus on the new results of atmospheric deposition flux for a number of chemical species, such as nutrients (e.g. nitrogen and phosphorus), acidic matters (e.g. sulfur and proton), heavy metals and Polycyclic Aromatic Hydrocarbons, etc. This is to our knowledge the first detailed element budget study in the atmosphere across Northern China. We find that: (1) Over the 3 year period, 26% of precipitation events in the target area were more acid than pH 5.60 and these acidic events occurred in summer and autumn. The annual volume-weighted mean (VWM) pH value of precipitation was lower than 5.60 at most sites, which indicated the acidification of precipitation was not optimistic. The primary ions in precipitation were NH4+, Ca2+, SO42- and NO3-, with 10-sites-average concentrations of 221, 216, 216 and 80 μeq L-1, respectively. The ratio of SO42- to NO3- was 2.7; suggesting SO42- was the dominant acid component. (2) The deposited particles were neutral in general and the pH value increased from rural area to industrial and coastal sites. It is not surprising to note that the annual VWM pH value of precipitation was higher than 5.60 at three urban sites (Beijing and Tianjin mega cities) and one coastal site near the Bohai Bay, considering the fact that high buffer capacity of alkaline component, gas NH3 and mineral aerosols, at these sites compared to other places. (3) The 10-sites annual total deposition amounts for sulfur and nitrogen compounds were 60 and 65 kg N/S ha-1 yr-1

Effects of vine water status on dimethyl sulfur potential, ammonium, and amino acid contents in Grenache Noir grapes (Vitis vinifera).

PubMed

De Royer Dupré, N; Schneider, R; Payan, J C; Salançon, E; Razungles, A

2014-04-02

We studied the effect of vine water status on the dimethyl sulfur potential (DMSP), ammonium, and amino acid contents of the berry during the maturation of Grenache Noir grapes. Water deficit increased the accumulation of amino acids in berries and favored yeast assimilable amino nitrogen. Similarly, ammonium content was higher in berries from vines subjected to moderate water deficit. DMSP content followed the same trend as yeast assimilable amino acid content, with higher concentrations observed in the berries of vines subjected to water deficit. The high DMSP and yeast assimilable nitrogen contents of musts from vines subjected to water deficit resulted in a better preservation of DMSP during winemaking. The wines produced from these musts had a higher DMSP level and would therefore probably have a higher aroma shelf life, because the DMSP determines the rate of release of dimethyl sulfur during wine storage, and this compound enhances fruity notes.

Metastable equilibria among dicarboxylic acids and the oxidation state during aqueous alteration on the CM2 chondrite parent body

NASA Astrophysics Data System (ADS)

McAlister, Jason A.; Kettler, Richard M.

2008-01-01

Linear saturated dicarboxylic acids are present in carbonaceous chondrite samples at concentrations that suggest aqueous alteration under conditions of metastable equilibrium. In this study, previously published values of dicarboxylic acid concentrations measured in Murchison, Yamato-791198, and Tagish Lake carbonaceous chondrites are converted to aqueous activities during aqueous alteration assuming water:rock ratios that range from 1:10 to 10:1. Logarithmic plots of the aqueous activities of any two dicarboxylic acids are proximal to lines whose slope is fixed by the stoichiometry of reactions describing the oxidation-reduction equilibrium between the two species. The precise position of any line is controlled by the equilibrium constant of the reaction relating the species and the hydrogen fugacity for the reaction of interest. Reactions among succinic (C4), glutaric (C5), and adipic (C6) acids obtained from CM2 chondrites show evidence of metastable equilibrium and yield logf values that agree to within 0.3 log units at 298.15 K and 0.6 log units at 473.15 K. At a water:rock ratio of 1:1, metastable equilibrium among succinic, glutaric, and adipic acids results in calculated logf values during aqueous alteration that range from -6.2 at 298.15 K to -3.3 at 373.15 K. These values are consistent with those obtained in previous work on carbonaceous chondrites and with metastable equilibrium at temperatures ranging from 300 to 355 K in contact with cronstedtite + magnetite.

Aqueous geochemistry of low molecular weight hydrocarbons at elevated temperatures and pressures: constraints from mineral buffered laboratory experiments

NASA Astrophysics Data System (ADS)

Seewald, Jeffrey S.

2001-05-01

Organic matter, water, and minerals coexist at elevated temperatures and pressures in sedimentary basins and participate in a wide range of geochemical processes that includes the generation of oil and natural gas. A series of laboratory experiments were conducted at 300 to 350°C and 350 bars to examine chemical interactions involving low molecular weight aqueous hydrocarbons with water and Fe-bearing minerals under hydrothermal conditions. Mineral buffers composed of hematite-magnetite-pyrite, hematite-magnetite, and pyrite-pyrrhotite-magnetite were added to each experiment to fix the redox state of the fluid and the activity of reduced sulfur species. During each experiment the chemical system was externally modified by addition of ethene, ethane, propene, 1-butene, or n-heptane, and variations in the abundance of aqueous organic species were monitored as a function of time and temperature. Results of the experiments indicate that decomposition of aqueous n-alkanes proceeds through a series of oxidation and hydration reactions that sequentially produce alkenes, alcohols, ketones, and organic acids as reaction intermediaries. Organic acids subsequently undergo decarboxylation and/or oxidation reactions to form carbon dioxide and shorter chain saturated hydrocarbons. This alteration assemblage is compositionally distinct from that produced by thermal cracking under anhydrous conditions, indicating that the presence of water and minerals provide alternative reaction pathways for the decomposition of hydrocarbons. The rate of hydrocarbon oxidation decreases substantially under reducing conditions and in the absence of catalytically active aqueous sulfur species. These results represent compelling evidence that the stability of aqueous hydrocarbons at elevated temperatures in natural environments is not a simple function of time and temperature alone. Under the appropriate geochemical conditions, stepwise oxidation represents a mechanism for the decomposition of low

Effect of Dietary Processed Sulfur Supplementation on Water-holding Capacity, Color, and Lipid Profiles of Pork

PubMed Central

Yang, FengQi; Kim, Ji-Han; Yeon, Su Jung; Hong, Go-Eun; Park, Woojoon; Lee, Chi-Ho

2015-01-01

This study was performed to investigate the effect of dietary processed sulfur supplementation on water-holding capacity, color, and lipid profiles of pork according to the level of dietary processed sulfur (0%, CON; 0.3%, S). The pigs were slaughtered at an average final weight of 120 kg, and the longissimus dorsi muscles were collected from the carcasses. As results, pork processed with sulfur had significantly higher moisture and ash contents compared to those of CON but lower crude fat, pH, expressible drip, lower redness and yellowness, and greater lightness. Pork processed with sulfur showed significantly lower total lipid content, triglycerides, and atherosclerosis index but significantly higher high-density lipoprotein cholesterol. Feeding processed sulfur significantly lowered myristic acid, heptadecanoic acid, and stearic acid contents, whereas monounsaturated fatty acids and oleic acids were significantly higher compared to those in the CON. Higher amounts of polyunsaturated fatty acids and n-6 fatty acids were observed in the pork processed with sulfur than that of the CON. Therefore, supplementing pigs with dietary sulfur improved nutrient and meat quality. PMID:26877643

40 CFR 60.82 - Standard for sulfur dioxide.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 7 2013-07-01 2013-07-01 false Standard for sulfur dioxide. 60.82... Plants § 60.82 Standard for sulfur dioxide. (a) On and after the date on which the performance test... contain sulfur dioxide in excess of 2 kg per metric ton of acid produced (4 lb per ton), the production...

40 CFR 60.82 - Standard for sulfur dioxide.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 7 2014-07-01 2014-07-01 false Standard for sulfur dioxide. 60.82... Plants § 60.82 Standard for sulfur dioxide. (a) On and after the date on which the performance test... contain sulfur dioxide in excess of 2 kg per metric ton of acid produced (4 lb per ton), the production...

40 CFR 60.82 - Standard for sulfur dioxide.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 6 2011-07-01 2011-07-01 false Standard for sulfur dioxide. 60.82... Plants § 60.82 Standard for sulfur dioxide. (a) On and after the date on which the performance test... contain sulfur dioxide in excess of 2 kg per metric ton of acid produced (4 lb per ton), the production...

40 CFR 60.82 - Standard for sulfur dioxide.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 7 2012-07-01 2012-07-01 false Standard for sulfur dioxide. 60.82... Plants § 60.82 Standard for sulfur dioxide. (a) On and after the date on which the performance test... contain sulfur dioxide in excess of 2 kg per metric ton of acid produced (4 lb per ton), the production...

40 CFR 60.82 - Standard for sulfur dioxide.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standard for sulfur dioxide. 60.82... Plants § 60.82 Standard for sulfur dioxide. (a) On and after the date on which the performance test... contain sulfur dioxide in excess of 2 kg per metric ton of acid produced (4 lb per ton), the production...

Vine-shoot waste aqueous extract applied as foliar fertilizer to grapevines: Effect on amino acids and fermentative volatile content.

PubMed

Sánchez-Gómez, R; Garde-Cerdán, T; Zalacain, A; Garcia, R; Cabrita, M J; Salinas, M R

2016-04-15

The aim of this work was to study the influence of foliar applications of different wood aqueous extracts on the amino acid content of musts and wines from Airén variety; and to study their relationship with the volatile compounds formed during alcoholic fermentation. For this purpose, the foliar treatments proposed were a vine-shoot aqueous extract applied in one and two times, and an oak extract which was only applied once. Results obtained show the potential of Airén vine-shoot waste aqueous extracts to be used as foliar fertilizer, enhancing the wine amino acid content especially when they were applied once. Similar results were observed with the aqueous oak extract. Regarding wine fermentative volatile compounds, there is a close relationship between musts and their wines amino acid content allowing us to discuss about the role of proline during the alcoholic fermentation and the generation of certain volatiles. Copyright © 2015 Elsevier Ltd. All rights reserved.

Distribution and size fractionation of elemental sulfur in aqueous environments: The Chesapeake Bay and Mid-Atlantic Ridge

NASA Astrophysics Data System (ADS)

Findlay, Alyssa J.; Gartman, Amy; MacDonald, Daniel J.; Hanson, Thomas E.; Shaw, Timothy J.; Luther, George W.

2014-10-01

Elemental sulfur is an important intermediate of sulfide oxidation and may be produced via abiotic and biotic pathways. In this study the concentration and size fractionation of elemental sulfur were measured in two different sulfidic marine environments: the Chesapeake Bay and buoyant hydrothermal vent plumes along the Mid-Atlantic Ridge. Nanoparticulate sulfur (<0.2 μm) was found to comprise up to 90% of the total elemental sulfur in anoxic deep waters of the Chesapeake Bay. These data were compared with previous studies of elemental sulfur, and represent one of the few reports of nanoparticulate elemental sulfur in the environment. Additionally, a strain of phototrophic sulfide oxidizing bacteria isolated from the Chesapeake Bay was shown to produce elemental sulfur as a product of sulfide oxidation. Elemental sulfur concentrations are also presented from buoyant hydrothermal vent plumes located along the Mid-Atlantic Ridge. In the Mid-Atlantic Ridge plume, S0 concentrations up to 33 μM were measured in the first meter of rising plumes at three different vent sites, and nanoparticulate S0 was up to 44% of total elemental sulfur present.

Aqueous extracts of Mozambican plants as alternative and environmentally safe acid-base indicators.

PubMed

Macuvele, Domingos Lusitaneo Pier; Sithole, Gerre Zebedias Samo; Cesca, Karina; Macuvele, Suzana Lília Pinare; Matsinhe, Jonas Valente

2016-06-01

Indicators are substances that change color as the pH of the medium. Many of these substances are dyes of synthetic origin. The mulala plant (Euclea natalensis), which roots are commonly used by rural communities for their oral hygiene, and roseira (Hibiscus rosa-sinensis), an ornamental plant, are abundant in Mozambique. Currently, synthetic acid-base indicators are most commonly used but have environmental implications and, on the other hand, are expensive products, so the demand for natural indicators started. This study investigated the applicability of aqueous extracts of H. rosa-sinensis and E. natalensis as acid-base indicators. Ground on this work, the extracts can be used as acid-base indicators. On the basis of the absorption spectroscopy in both the UV-Vis region and previous studies, it was possible to preliminarily pinpoint anthocyanins and naphthoquinones as responsible for the shifting of colors depending on the pH range of aqueous extracts of H. rosa-sinensis and E. natalensis. These natural indicators are easily accessible, inexpensive, easy to extract, environmentally safe, and locally available.

Detecting Sulfuric and Nitric Acid Rain Stresses on Quercus glauca through Hyperspectral Responses

PubMed Central

Wang, Shanqian; Zhang, Xiuying; Ma, Yuandan; Li, Xinhui; Zhang, Xiaomin; Liu, Lei

2018-01-01

Acid rain, which has become one of the most severe global environmental issues, is detrimental to plant growth. However, effective methods for monitoring plant responses to acid rain stress are currently lacking. The hyperspectral technique provides a cost-effective and nondestructive way to diagnose acid rain stresses. Taking a widely distributed species (Quercus glauca) in Southern China as an example, this study aims to monitor the hyperspectral responses of Q. glauca to simulated sulfuric acid rain (SAR) and nitric acid rain (NAR). A total of 15 periods of leaf hyperspectral data under four pH levels of SAR and NAR were obtained during the experiment. The results showed that hyperspectral information could be used to distinguish plant responses under acid rain stress. An index (green peak area index, GPAI) was proposed to indicate acid rain stresses, based on the significantly variations in the region of 500–660 nm. Light acid rain (pH 4.5 SAR and NAR) promoted Q. glauca growth relative to the control groups (pH 5.6 SAR and NAR); moderate acid rain (pH 3.0 SAR) firstly promoted and then inhibited plant growth, while pH 3.0 NAR showed mild inhibitory effects during the experiment; and heavy acid rain (pH 2.0) significantly inhibited plant growth. Compared with NAR, SAR induced more serious damages to Q. glauca. These results could help monitor acid rain stress on plants on a regional scale using remote sensing techniques. PMID:29522488

Detecting Sulfuric and Nitric Acid Rain Stresses on Quercus glauca through Hyperspectral Responses.

PubMed

Wang, Shanqian; Zhang, Xiuying; Ma, Yuandan; Li, Xinhui; Cheng, Min; Zhang, Xiaomin; Liu, Lei

2018-03-09

Acid rain, which has become one of the most severe global environmental issues, is detrimental to plant growth. However, effective methods for monitoring plant responses to acid rain stress are currently lacking. The hyperspectral technique provides a cost-effective and nondestructive way to diagnose acid rain stresses. Taking a widely distributed species ( Quercus glauca ) in Southern China as an example, this study aims to monitor the hyperspectral responses of Q. glauca to simulated sulfuric acid rain (SAR) and nitric acid rain (NAR). A total of 15 periods of leaf hyperspectral data under four pH levels of SAR and NAR were obtained during the experiment. The results showed that hyperspectral information could be used to distinguish plant responses under acid rain stress. An index (green peak area index, GPAI) was proposed to indicate acid rain stresses, based on the significantly variations in the region of 500-660 nm. Light acid rain (pH 4.5 SAR and NAR) promoted Q. glauca growth relative to the control groups (pH 5.6 SAR and NAR); moderate acid rain (pH 3.0 SAR) firstly promoted and then inhibited plant growth, while pH 3.0 NAR showed mild inhibitory effects during the experiment; and heavy acid rain (pH 2.0) significantly inhibited plant growth. Compared with NAR, SAR induced more serious damages to Q. glauca . These results could help monitor acid rain stress on plants on a regional scale using remote sensing techniques.

Effects of simulated acid rain, ozone and sulfur dioxide on suitability of elms for elm leaf beetle

Treesearch

Richard W. Hall; Jack H. Barger; Alden M. Townsend

1988-01-01

Cuttings from two clonally propagated elm hybrids ('Pioneer' and 'Homestead') were treated with ozone (03), sulfur dioxide (S02), simulated acid rain or left untreated. Fumigants were applied 7 hours per day, 5 days per week for 9 weeks in open-top chambers. Fumigation treatments were: 0.1 ppm 0

Dealing with methionine/homocysteine sulfur: cysteine metabolism to taurine and inorganic sulfur

PubMed Central

Ueki, Iori

2010-01-01

Synthesis of cysteine as a product of the transsulfuration pathway can be viewed as part of methionine or homocysteine degradation, with cysteine being the vehicle for sulfur conversion to end products (sulfate, taurine) that can be excreted in the urine. Transsulfuration is regulated by stimulation of cystathionine β-synthase and inhibition of methylene tetrahydrofolate reductase in response to changes in the level of S-adenosylmethionine, and this promotes homocysteine degradation when methionine availability is high. Cysteine is catabolized by several desulfuration reactions that release sulfur in a reduced oxidation state, generating sulfane sulfur or hydrogen sulfide (H2S), which can be further oxidized to sulfate. Cysteine desulfuration is accomplished by alternate reactions catalyzed by cystathionine β-synthase and cystathionine γ-lyase. Cysteine is also catabolized by pathways that require the initial oxidation of the cysteine thiol by cysteine dioxygenase to form cysteinesulfinate. The oxidative pathway leads to production of taurine and sulfate in a ratio of approximately 2:1. Relative metabolism of cysteine by desulfuration versus oxidative pathways is influenced by cysteine dioxygenase activity, which is low in animals fed low-protein diets and high in animals fed excess sulfur amino acids. Thus, desulfuration reactions dominate when cysteine is deficient, whereas oxidative catabolism dominates when cysteine is in excess. In rats consuming a diet with an adequate level of sulfur amino acids, about two thirds of cysteine catabolism occurs by oxidative pathways and one third by desulfuration pathways. Cysteine dioxygenase is robustly regulated in response to cysteine availability and may function to provide a pathway to siphon cysteine to less toxic metabolites than those produced by cysteine desulfuration reactions. PMID:20162368

A composite of hollow carbon nanospheres and sulfur-rich polymers for lithium-sulfur batteries

NASA Astrophysics Data System (ADS)

Zeng, Shao-Zhong; Yao, Yuechao; Zeng, Xierong; He, Qianjun; Zheng, Xianfeng; Chen, Shuangshuang; Tu, Wenxuan; Zou, Jizhao

2017-07-01

Lithium-sulfur batteries are the most promising candidates for future high-energy applications because of the unparalleled capacity of sulfur (1675 mAh g-1). However, lithium-sulfur batteries have limited cycle life and rate capability due to the dissolution of polysulfides and the extremely low electronic conductivity of sulfur. To solve these issues, various porous carbons including hollow carbon nanospheres (HCNs) have been used for improving the conductivity. However, these methods still suffer from polysulfides dissolution/loss owing to their weak physical adsorption to polysulfides. Herein, we introduced a covalent grafting route to composite the HCNs and the vulcanized trithiocyanuric acid (TTCA). The composite exhibits a high loading of the vulcanized TTCA by the HCNs with high surface area and large pore volume, and covalent bonds to sulfur, effectively depressing the dissolution of polysulfides. The first discharge capacity of the composite reaches 1430 mAh g-1 at 0.1 C and 1227 mAh g-1 at 0.2 C.

Pretreatment of Human Epidermal Keratinocytes In Vitro With Ethacrynic Acid Reduces Sulfur Mustard Cytotoxicity

DTIC Science & Technology

2004-01-01

estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the...display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1 . REPORT DATE (DD-MM-YYYY) 2. REPORT TYPE 3. DATES...Ethacrynic Acid Reduces 5b. GRANT NUMBER Sulfur Mustard Toxicity 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER Gross, CL, Nipwoda, MT, Nealley

Restraint stress in lactating mice alters the levels of sulfur-containing amino acids in milk.

PubMed

Nishigawa, Takuma; Nagamachi, Satsuki; Ikeda, Hiromi; Chowdhury, Vishwajit S; Furuse, Mitsuhiro

2018-03-30

It is well known that maternal stress during the gestation and lactation periods induces abnormal behavior in the offspring and causes a lowering of the offspring's body weight. Various causes of maternal stress during the lactation period, relating to, for example, maternal nutritional status and reduced maternal care, have been considered. However, little is known about the effects on milk of maternal stress during the lactation period. The current study aimed to determine whether free amino acids, with special reference to sulfur-containing amino acids in milk, are altered by restraint stress in lactating mice. The dams in the stress group were restrained for 30 min at postnatal days 2, 4, 6, 8, 10 and 12. Restraint stress caused a reduction in the body weight of lactating mice. The concentration of taurine and cystathionine in milk was significantly higher in the stress group, though stress did not alter their concentration in maternal plasma. The ratio of taurine concentration in milk to its concentration in maternal plasma was significantly higher in the stress group, suggesting that stress promoted taurine transportation into milk. Furthermore, taurine concentration in milk was positively correlated with corticosterone levels in plasma. In conclusion, restraint stress in lactating mice caused the changes in the metabolism and in the transportation of sulfur-containing amino acids and resulted in higher taurine concentration in milk. Taurine concentration in milk could also be a good parameter for determining stress status in dams.

Sulfur recirculation for increased electricity production in Waste-to-Energy plants.

PubMed

Andersson, Sven; Blomqvist, Evalena W; Bäfver, Linda; Jones, Frida; Davidsson, Kent; Froitzheim, Jan; Karlsson, Martin; Larsson, Erik; Liske, Jesper

2014-01-01

Sulfur recirculation is a new technology for reducing boiler corrosion and dioxin formation. It was demonstrated in full-scale tests at a Waste to Energy plant in Göteborg (Sweden) during nearly two months of operation. Sulfur was recirculated as sulfuric acid from the flue gas cleaning back to the boiler, thus creating a sulfur loop. The new technology was evaluated by extensive measurement campaigns during operation under normal conditions (reference case) and operation with sulfur recirculation. The chlorine content of both fly ash and boiler ash decreased and the sulfur content increased during the sulfur recirculation tests. The deposit growth and the particle concentration decreased with sulfur recirculation and the dioxin concentration (I-TEQ) of the flue gas was reduced by approximately 25%. Sulfuric acid dew point measurements showed that the sulfuric acid dosage did not lead to elevated SO3 concentrations, which may otherwise induce low temperature corrosion. In the sulfur recirculation corrosion probe exposures, the corrosion rate decreased for all tested materials (16Mo3, Sanicro 28 and Inconel 625) and material temperatures (450 °C and 525 °C) compared to the reference exposure. The corrosion rates were reduced by 60-90%. Sulfur recirculation prevented the formation of transition metal chlorides at the metal/oxide interface, formation of chromate and reduced the presence of zinc in the corrosion products. Furthermore, measured corrosion rates at 525 °C with sulfur recirculation in operation were similar or lower compared to those measured at 450 °C material temperature in reference conditions, which corresponds to normal operation at normal steam temperatures. This implies that sulfur recirculation allows for higher steam data and electricity production without increasing corrosion. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

High-Yield Production of Levulinic Acid from Pretreated Cow Dung in Dilute Acid Aqueous Solution.

PubMed

Su, Jialei; Shen, Feng; Qiu, Mo; Qi, Xinhua

2017-02-14

Agricultural waste cow dung was used as feedstock for the production of a high value-added chemical levulinic acid (LA) in dilute acid aqueous solutions. A high LA yield of 338.9 g/kg was obtained from the pretreated cow dung, which was much higher than that obtained from the crude cow dung (135 g/kg), mainly attributed to the breakage of the lignin fraction in the lignocellulose structure of the cow dung by potassium hydroxide (KOH) pretreatment, and thus enhanced the accessibility of cow dung to the acid sites in the catalytic reaction. Meanwhile, another value-added chemical formic acid could be obtained with a yield of ca. 160 g/kg in the process, implying a total production of ca. 500 g/kg yield for LA and formic acid from the pretreated cow dung with the proposed process. The developed process was shown to be tolerant to high initial substrate loading with a satisfied LA yield. This work provides a promising strategy for the value-increment utilization of liglocellulosic agricultural residues.

The fate of sulfur in mild gasification liquids

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

Knight, R.A.; Koncar, G.J.; Babu, S.P.

1991-01-01

This investigation addresses the determination of sulfur distribution in mild gasification liquids produced from untreated coal and from modified in two ways to reduce sulfur in the products: (a) physical mixing with a sulfur scavenger (CaO), and (b) pretreatment with aqueous alkali followed by mixing with CaO. Coal pyrolysis in the presence of CaO has previously been investigated, (3,5) showing that CaO can be effective in reducing the sulfur content of the fuel gas, and possibly that of the product liquids. Pretreatment of coals with alkaline chemicals has also been studied,(6,7) showing reduced sulfur and other changes in the liquidmore » products.(8) Data on sulfur distribution in the liquid products could be useful for understanding the chemistry of alkali pretreatment and CaO interaction with coal sulfur during pyrolysis. In this work, a pyrolysis-gas chromatography (Py-GC) technique that simulates mild gasification on a milligram scale was used in conjunction with a carbon-specific flame ionization detector (FID) and a sulfur-specific flame photometric detector (FPD) to determine the sulfur distribution in oils/tars from Illinois No. 6 coal. A low-resolution packed GC column was employed to resolve oils/tars by carbon number, with ranges selected to approximate distillation fractions which might be recovered from a commercial mild gasification process. Oils/tars up to C{sub 18} were also collected from the pyro-probe effluent into dichloromethane for off-line study using a high-resolution GC with atomic emission detector (GC/AED) and with GC-mass spectrometry (GC/MS) to measure specific sulfur compounds. 9 refs., 1 tab.« less

Effect of tritium on corrosion behavior of chromium in 0.01 N sulfuric acid solution

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

Oyaidzu, M.; Isobe, K.; Hayashi, T.

The effects of tritium on the corrosion behavior of chromium in 0.01 N sulfuric solution have been investigated in the present study. Electrochemical experiments have been carried our for pure chromium. At first, the concentration dependence of sulfuric acid solution on anodic polarization behavior of chromium was experimented, resulting in that 0.01 N one was found appropriate. The dependence of both dissolved oxygen and tritium concentration on anodic behavior of chromium were performed. It was found from that the self-passivation of chromium induced by dissolved oxygen was inhibited in tritiated solution resulting in the enhancement of the corrosion. As amore » consequence it is highly likely that the elution of chromium by highly oxidative radiolysis products would explain the passivation inhibitory effect of SUS304 stainless steel observed in tritiated solutions.« less

Organic Sulfur Associated with Aquatic Humic Substances

NASA Astrophysics Data System (ADS)

Aiken, G.; Vairavamurthy, M. A.; Ravichandran, M.

2003-12-01

This study examines the speciation and reactivity of organic sulfur associated with dissolved organic matter isolated from a variety of freshwater environments and the Pacific Ocean. The isolates, which included aquatic humic substances, were obtained using XAD resins and exhibited a wide range of elemental compositions, aromatic carbon contents, and molecular weights. Organic sulfur contents for the samples ranged from 0.4% to 1.9% of the atomic composition and were strongly dependent on the redox chemistry of the environments whence the samples originated, especially with regard to potential interactions with sulfide in sulfate reducing environments. The speciation of the sulfur associated with these samples was investigated using X-ray adsorption near edge spectroscopy (XANES). The samples, all obtained from oxic environments, contained reduced sulfur moieties. Reduced sulfur content (thiophene, organic sulfides and thiols) ranged from 22-70%. In general, humic acid fractions were found to have the largest percentage of reduced sulfur, followed by the fulvic acid and hydrophobic acid fractions. Hydrophilic fractions of the DOC contained a large percentage of oxidized organic sulfur (sulfonate and sulfate moieties). To assess the significance of reduced S content on interactions with soft metals, an environmentally significant process, the binding strength and binding capacity of Hg with organic matter isolated from the Florida Everglades were determined using equilibrium dialysis ligand exchange. Based on elemental analyses and XANES, the DOM sample from the Everglades used in our binding experiments had a reduced-S content of approximately 1.0%. Very strong interactions (KDOM' = 1023.2+/-0.5 L kg-1) were observed at Hg/DOM ratios below approximately 1 μ g Hg per mg DOM. Only a small fraction (approximately 2%) of the reduced-S groups were involved with the strongest interactions between Hg and DOM, suggesting that the binding of Hg to DOM under natural

Sulfur Biogeochemistry of an Oil Sands Composite Tailings Deposit

PubMed Central

Warren, Lesley A.; Kendra, Kathryn E.; Brady, Allyson L.; Slater, Greg F.

2016-01-01

Composite tailings (CT), an engineered, alkaline, saline mixture of oil sands tailings (FFT), processed sand and gypsum (CaSO4; 1 kg CaSO4 per m3 FFT) are used as a dry reclamation strategy in the Alberta Oil Sands Region (AOSR). It is estimated that 9.6 × 108 m3 of CT are either in, or awaiting emplacement in surface pits within the AOSR, highlighting their potential global importance in sulfur cycling. Here, in the first CT sulfur biogeochemistry investigation, integrated geochemical, pyrosequencing and lipid analyses identified high aqueous concentrations of ∑H2S (>300 μM) and highly altered sulfur compounds composition; low cell biomass (3.3 × 106– 6.0 × 106 cells g−1) and modest bacterial diversity (H' range between 1.4 and 1.9) across 5 depths spanning 34 m of an in situ CT deposit. Pyrosequence results identified a total of 29,719 bacterial 16S rRNA gene sequences, representing 131 OTUs spanning19 phyla including 7 candidate divisions, not reported in oil sands tailings pond studies to date. Legacy FFT common phyla, notably, gamma and beta Proteobacteria, Firmicutes, Actinobacteria, and Chloroflexi were represented. However, overall CT microbial diversity and PLFA values were low relative to other contexts. The identified known sulfate/sulfur reducing bacteria constituted at most 2% of the abundance; however, over 90% of the 131 OTUs identified are capable of sulfur metabolism. While PCR biases caution against overinterpretation of pyrosequence surveys, bacterial sequence results identified here, align with phospholipid fatty acid (PLFA) and geochemical results. The highest bacterial diversities were associated with the depth of highest porewater [∑H2S] (22–24 m) and joint porewater co-occurrence of Fe2+ and ∑H2S (6–8 m). Three distinct bacterial community structure depths corresponded to CT porewater regions of (1) shallow evident Fe(II) (<6 m), (2) co-occurring Fe(II) and ∑H2S (6–8 m) and (3) extensive ∑H2S (6–34 m) (Uni

SULFATE-SULFUR METABOLISM IN THE RAT FETUS AS INDICATED BY SULFUR-35

PubMed Central

Dziewiatkowski, Dominic D.

1953-01-01

Twenty-four hours after the intraperitoneal injection of sodium sulfate-S35 into pregnant rats, sulfur-35 was found in the embryos. The amount of the sulfur-35 retained by the embryos was directly related to their degree of development in utero. A large fraction of the sulfur-35 found in the embryos was insoluble in 5 per cent trichloroacetic acid. At the 9th to 10th day of development, about 40 per cent of the sulfur-35 was present in this fraction. In 20-day-old embryos this fraction accounted for nearly 90 per cent of the total. Radioautographs of sections of embryos fixed in a solution of formaldehyde revealed that the sulfur-35 was most highly concentrated in the cartilaginous portion of the skeleton. All other tissues gave much weaker autographic reactions, comparable with the over-all reaction obtained when sections from embryos fixed in a solution of formaldehyde saturated with barium hydroxide were used. By analysis for the sulfur-35 content of individual tissues the concentration of the sulfur-35 in humeri from 20-day-old embryos was found to be about 30 times that in the maternal sternum. The concentration of the isotope in the skeletal muscle, brain, heart, and skin of the same embryos was also higher than in the corresponding maternal tissues. On the other hand, the concentration of the sulfur-35 in the maternal gastrointestinal tract plus contents was higher than in the gastrointestinal tract and contents of the embryos. PMID:13069655

Vertical profiles of H2O, H2SO4, and sulfuric acid concentration at 45-75 km on Venus

NASA Astrophysics Data System (ADS)

Krasnopolsky, Vladimir A.

2015-05-01

A method developed by Krasnopolsky and Pollack (Krasnopolsky, V.A., Pollack, J.B. [1994]. Icarus 109, 58-78) to model vertical profiles of H2O and H2SO4 vapors and sulfuric acid concentration in the Venus cloud layer has been updated with improved thermodynamic parameters for H2O and H2SO4 and reduced photochemical production of sulfuric acid. The model is applied to the global-mean conditions and those at the low latitudes and at 60°. Variations in eddy diffusion near the lower cloud boundary are used to simulate variability in the cloud properties and abundances of H2O and H2SO4. The best version of the model for the global-mean condition results in a lower cloud boundary (LCB) at 47.5 km, H2SO4 peak abundance of 7.5 ppm at the LCB, and H2O mixing ratios of 7 ppm at 62 km and 3.5 ppm above 67 km. The model for low latitudes gives LCB at 48.5 km, the H2SO4 peak of 5 ppm, H2O of 8.5 ppm at 62 km and 3 ppm above 67 km. The model for 60° shows LCB at 46 km, the H2SO4 peak of 8.5 ppm, H2O of 9 ppm at 62 km and 4.5 ppm above 67 km. The calculated variability is induced by the proper changes in the production of sulfuric acid (by factors of 1.2 and 0.7 for the low latitudes and 60°, respectively) and reduction of eddy diffusion near 45 km relative to the value at 54 km by factors of 1.1, 3, and 4.5 for the low and middle (global-mean) latitudes and 60°, respectively. Concentration of sulfuric acid at the low and middle latitudes varies from ∼98% near 50 km to ∼80% at 60 km and then is almost constant at 79% at 70 km. Concentration at 60° is 98% at 50 km, 73% at 63 km, and 81% at 70 km. There is a reasonable agreement between the model results and observations except for the sulfuric acid concentration in the lower clouds. Variations of eddy diffusion in the lower cloud layer simulate variations in atmospheric dynamics and may induce strong variations in water vapor near the cloud tops. Variations in temperature may affect abundances of the H2O and H2SO4 vapors

40 CFR 721.9672 - Amides, tall-oil fatty, N-[2-[2-hydroxyethyl)amino]ethyl], reaction products with sulfur dioxide...

Code of Federal Regulations, 2013 CFR

2013-07-01

...-hydroxyethyl)amino]ethyl], reaction products with sulfur dioxide; fatty acids, tall-oil, reaction products with 1-piperazineethanamine and sulfur dioxide; fatty acids, tall-oil reaction products with sulfur...)amino]ethyl], reaction products with sulfur dioxide; fatty acids, tall-oil, reaction products with 1...

40 CFR 721.9672 - Amides, tall-oil fatty, N-[2-[2-hydroxyethyl)amino]ethyl], reaction products with sulfur dioxide...

Code of Federal Regulations, 2011 CFR

2011-07-01

...-hydroxyethyl)amino]ethyl], reaction products with sulfur dioxide; fatty acids, tall-oil, reaction products with 1-piperazineethanamine and sulfur dioxide; fatty acids, tall-oil reaction products with sulfur...)amino]ethyl], reaction products with sulfur dioxide; fatty acids, tall-oil, reaction products with 1...

40 CFR 721.9672 - Amides, tall-oil fatty, N-[2-[2-hydroxyethyl)amino]ethyl], reaction products with sulfur dioxide...

Code of Federal Regulations, 2010 CFR

2010-07-01

...-hydroxyethyl)amino]ethyl], reaction products with sulfur dioxide; fatty acids, tall-oil, reaction products with 1-piperazineethanamine and sulfur dioxide; fatty acids, tall-oil reaction products with sulfur...)amino]ethyl], reaction products with sulfur dioxide; fatty acids, tall-oil, reaction products with 1...

A Branch Point of Streptomyces Sulfur Amino Acid Metabolism Controls the Production of Albomycin

PubMed Central

Kulkarni, Aditya; Zeng, Yu; Zhou, Wei; Van Lanen, Steven; Zhang, Weiwen

2015-01-01

Albomycin (ABM), also known as grisein, is a sulfur-containing metabolite produced by Streptomyces griseus ATCC 700974. Genes predicted to be involved in the biosynthesis of ABM and ABM-like molecules are found in the genomes of other actinomycetes. ABM has potent antibacterial activity, and as a result, many attempts have been made to develop ABM into a drug since the last century. Although the productivity of S. griseus can be increased with random mutagenesis methods, understanding of Streptomyces sulfur amino acid (SAA) metabolism, which supplies a precursor for ABM biosynthesis, could lead to improved and stable production. We previously characterized the gene cluster (abm) in the genome-sequenced S. griseus strain and proposed that the sulfur atom of ABM is derived from either cysteine (Cys) or homocysteine (Hcy). The gene product, AbmD, appears to be an important link between primary and secondary sulfur metabolic pathways. Here, we show that propargylglycine or iron supplementation in growth media increased ABM production by significantly changing the relative concentrations of intracellular Cys and Hcy. An SAA metabolic network of S. griseus was constructed. Pathways toward increasing Hcy were shown to positively impact ABM production. The abmD gene and five genes that increased the Hcy/Cys ratio were assembled downstream of hrdBp promoter sequences and integrated into the chromosome for overexpression. The ABM titer of one engineered strain, SCAK3, in a chemically defined medium was consistently improved to levels ∼400% of the wild type. Finally, we analyzed the production and growth of SCAK3 in shake flasks for further process development. PMID:26519385

Emissions of sulfur trioxide from coal-fired power plants.

PubMed

Srivastava, R K; Miller, C A; Erickson, C; Jambhekar, R

2004-06-01

Emissions of sulfur trioxide (SO3) are a key component of plume opacity and acid deposition. Consequently, these emissions need to be low enough to not cause opacity violations and acid deposition. Generally, a small fraction of sulfur (S) in coal is converted to SO3 in coal-fired combustion devices such as electric utility boilers. The emissions of SO3 from such a boiler depend on coal S content, combustion conditions, flue gas characteristics, and air pollution devices being used. It is well known that the catalyst used in the selective catalytic reduction (SCR) technology for nitrogen oxides control oxidizes a small fraction of sulfur dioxide in the flue gas to SO3. The extent of this oxidation depends on the catalyst formulation and SCR operating conditions. Gas-phase SO3 and sulfuric acid, on being quenched in plant equipment (e.g., air preheater and wet scrubber), result in fine acidic mist, which can cause increased plume opacity and undesirable emissions. Recently, such effects have been observed at plants firing high-S coal and equipped with SCR systems and wet scrubbers. This paper investigates the factors that affect acidic mist production in coal-fired electric utility boilers and discusses approaches for mitigating emission of this mist.

Kinetics of beta-haematin formation from suspensions of haematin in aqueous benzoic acid.

PubMed

Egan, Timothy J; Tshivhase, Mmboneni G

2006-11-14

Kinetics of beta-haematin (synthetic malaria pigment) formation from haematin have been studied in the presence of aqueous benzoic acid and derivatives of benzoic acid. Formation of the beta-haematin product is demonstrated by X-ray diffraction and IR spectroscopy. Reactions were followed by determining the fraction of unreacted haematin at various time points during the process via reaction of extracted aliquots with pyridine. The kinetics can be fitted to the Avrami equation, indicating that the process involves nucleation and growth. Reaction kinetics in stirred benzoic acid are similar to those previously observed in acetic acid, except that benzoic acid is far more active in promoting the reaction than acetic acid. The reaction reaches completion within 2 h in the presence of 0.050 M benzoic acid (pH 4.5, 60 degrees C). This compares with 1 h in the presence of 4.5 M acetic acid and 4 h in the presence of 2 M acetic acid. The reaction rate in benzoic acid is not affected if the stirring rate is decreased to zero, but very vigorous stirring appears to disrupt nucleation. The rate constant for beta-haematin formation in benzoic acid has a linear dependence on benzoic acid concentration and follows Arrhenius behaviour with temperature. There is a bell-shaped dependence on pH. This suggests that the haematin species in which one propionate group is protonated and the other is deprotonated is optimal for beta-haematin formation. When the reaction is conducted in para-substituted benzoic acid derivatives, the log of the rate constant increases linearly with the Hammett constant. These findings suggest that the role of the carboxylic acid may be to disrupt hydrogen bonding and pi-stacking in haematin, facilitating conversion to beta-haematin. The large activation energy for conversion of precipitated haematin to beta-haematin suggests that the reaction in vivo most likely involves direct nucleation from solution and probably does not occur in aqueous medium.

Sulfur in Distillers Grains for Dairy Cattle

USDA-ARS?s Scientific Manuscript database

Sulfur is an essential element needed by animals for many functions. About 0.15% of the body weight is sulfur. It is found in the amino acids methionine, cysteine, cystine, homocysteine, and taurine; in chondroitin sulfate of cartilage; and in the B-vitamins, thiamin and biotin. Methionine, thiam...

Loss of sulfur dioxide and changes in some chemical properties of Malatya apricots (Prunus armeniaca L.) during sulfuring and drying.

PubMed

Türkyılmaz, Meltem; Özkan, Mehmet; Güzel, Nihal

2014-09-01

This study was conducted to determine the differences in some analytical properties of four apricot cultivars and to determine the changes in these analytical properties during sulfuring and sun-drying. There were significant differences in the contents of polyphenols, carotenoids and organic acids (OA) as well as antioxidant activities (AOAs) of the cultivars (P < 0.05). After sulfuring and drying, considerable reductions were detected in the contents of total polyphenols (TPCs, 11-26%), OAs (4-32%) and β-carotene (6-21%), and AOAs (2-21%) of the samples. Sun-drying resulted in 71-83% decreases in sulfur dioxide (SO2 ) contents of sulfured-dried apricots (SDAs) in comparison with apricots immediately after sulfuring. As the TPCs increased, the SO2 absorption by the samples also increased. In contrast, the OA contents had no effect on SO2 absorption, but an increase in OA content resulted in an increase in the browning values of the SDAs. As expected, increases in contents of ferulic acid (r = 0.932), chlorogenic acid (r = 0.850), epicatechin (r = 0.804) and quercetin (r = 0.750) led to an increase in browning values of the SDAs. There were significant effects of cultivar and processing on the physico-chemical properties investigated in the study, and with the absorption of SO2 and the formation of a brown colour in the samples. © 2014 Society of Chemical Industry.

Absorption and emission behaviour of trans- p-coumaric acid in aqueous solutions and some organic solvents

NASA Astrophysics Data System (ADS)

Putschögl, M.; Zirak, P.; Penzkofer, A.

2008-01-01

The absorption and fluorescence behaviour of trans- p-coumaric acid ( trans-4-hydroxycinnamic acid) is investigated in buffered aqueous solution over a wide range from pH 1 to pH 12, in un-buffered water, and in some organic solvents. Absorption cross-section spectra, fluorescence quantum distributions, fluorescence quantum yields, and degrees of fluorescence polarisation are measured. p-Coumaric acid exists in different ionic forms in aqueous solution depending on the pH. There is an equilibrium between the neutral form ( p-CAH 2) and the single anionic form ( p-CAH -) at low pH (p Kna ≈ 4.9), and between the single anionic and the double anionic form ( p-CA 2-) at high pH (p Kaa ≈ 9.35). In the organic solvents studied trans- p-coumaric acid is dissolved in its neutral form. The fluorescence quantum yield of trans- p-coumaric acid in aqueous solution is ϕF ≈ 1.4 × 10 -4 for the neutral and the single anionic form, while it is ϕF ≈ 1.3 × 10 -3 for the double anionic form. For trans- p-coumaric acid in organic solvents fluorescence quantum yields in the range from 4.8 × 10 -5 (acetonitrile) to 1.5 × 10 -4 (glycerol) were measured. The fluorescence spectra are 7700-10,000 cm -1 Stokes shifted in aqueous solution, and 5400-8200 cm -1 Stokes shifted in the studied organic solvents. Decay paths responsible for the low fluorescence quantum yields are discussed (photo-isomerisation and internal conversion for p-CA 2-, solvent-assisted intra-molecular charge-transfer or ππ ∗ to nπ ∗ transfer and internal conversion for p-CAH 2 and p-CAH -). The solvent dependence of the first ππ ∗ electronic transition frequency and of the fluorescence Stokes shift of p-CAH 2 is discussed in terms of polar solute-solvent interaction effects. Thereby the ground-state and excite-state molecular dipole moments are extracted.

Effective Dual Polysulfide Rejection by a Tannic Acid/FeIII Complex-Coated Separator in Lithium-Sulfur Batteries.

PubMed

Zhang, Hong; Lin, Chuner; Hu, Xuanhe; Zhu, Baoku; Yu, Dingshan

2018-04-18

The solubility behaviour of polysulfides in electrolyte solutions is a major bottleneck prior to the practical application of the lithium-sulfur battery. To address this issue, we fabricate a tannic acid/Fe III complex-coated polypropylene (PP) separator (TA/Fe III -PP separator) via a simple, fast, and green method. Benefiting from dual-confinement effects based on Lewis acid-base interactions between Fe III and polysulfides as well as the dipole-dipole interactions between rich phenol groups and polysulfides, the migration of polysulfides is effectively suppressed. Meanwhile, the porous structure of the PP separator is not destroyed by an additional coating layer. Thus, the TA/Fe III -PP separator can retain rapid lithium ion transport, eventually leading to a significant improvement in both the discharge capacity and rate performance of the corresponding lithium-sulfur cells. The cell with the TA/Fe III -PP separator presents a low capacity fade of 0.06% per cycle over 1000 cycles at 2.0 C, along with a high Coulombic efficiency of >97% over 300 cycles at 0.5 C. With respect to the one with the bare PP separator, the cell with the TA/Fe III -PP separator exhibits a 1.7-fold increase in the discharge capacity at 3.0 C. The proposed simple and economical approach shows great potential in constructing advanced separators to retard the shuttle effect of polysulfides for lithium-sulfur batteries.

A novel process for low-sulfur biodiesel production from scum waste.

PubMed

Ma, Huan; Addy, Min M; Anderson, Erik; Liu, Weiwei; Liu, Yuhuan; Nie, Yong; Chen, Paul; Cheng, Beijiu; Lei, Hanwu; Ruan, Roger

2016-08-01

Scum is an oil-rich waste from the wastewater treatment plants with a high-sulfur level. In this work, a novel process was developed to convert scum to high quality and low sulfur content biodiesel. A combination of solvent extraction and acid washing as pretreatment was developed to lower the sulfur content in the scum feedstock and hence improve biodiesel conversion yield and quality. Glycerin esterification was then employed to convert free fatty acids to glycerides. Moreover, a new distillation process integrating the traditional reflux distillation and adsorptive desulfurization was developed to further remove sulfur from the crude biodiesel. As a result, 70% of the filtered and dried scum was converted to biodiesel with sulfur content lower than 15ppm. The fatty acid methyl ester profiles showed that the refined biodiesel from the new process exhibited a higher quality and better properties than that from traditional process reported in previous studies. Copyright © 2016 Elsevier Ltd. All rights reserved.

Understanding the dissolution of α-zein in aqueous ethanol and acetic acid solutions.

PubMed

Li, Yunqi; Li, Ji; Xia, Qiuyang; Zhang, Boce; Wang, Qin; Huang, Qingrong

2012-10-04

Zein is a corn prolamin that has broad industrial applications because of its unique physical properties. Currently, the high cost of extraction and purification, which is directly related to the dispersion of zein in different solvents, is the major bottleneck of the zein industry. Solution behaviors of zein have been studied for a long time. However, the physical nature of zein in different solvents remains unclear. In this study, small-angle X-ray scattering (SAXS), static light scattering (SLS), and rheology were combined to study the structure and protein-solvent interaction of α-zein in both acetic acid and aqueous ethanol solutions. We found that the like-dissolve-like rule, the partial unfolding, and the protonation of zein are all critical to understanding the solution behaviors. Zein holds an elongated conformation (i.e., prolate ellipsoid) in all solutions, as revealed from SAXS data. There is an "aging effect" for zein in aqueous ethanol solutions, as evidenced by the transition of Newtonian rheological profiles for fresh zein solutions to the non-Newtonian shear thinning behavior for zein solutions after storage at room temperature for 24 h. Such shear thinning behavior becomes more pronounced for zein solutions at higher concentrations. The SLS results clearly show that acetic acid is a better solvent to dissolve zein than aqueous ethanol solution, as supported by a more negative second virial coefficient. This is majorly caused by the protonation of the protein, which was further verified by the dissolution of zein in water (a nonsolvent for zein) with the addition of acids.

Kinetics and mechanism of S-nitrosothiol acid-catalyzed hydrolysis: sulfur activation promotes facile NO+ release.

PubMed

Moran, Ernesto E; Timerghazin, Qadir K; Kwong, Elizabeth; English, Ann M

2011-03-31

The denitrosation of three primary S-nitrosothiols (RSNO; S-nitrosocysteine, S-nitroso-N-acetylcysteine, and S-nitrosoglutathione) and two tertiary RSNOs (S-nitrosopenicillamine and S-nitroso-N-acetylpenicillamine) was investigated in 3.75 M H(2)SO(4) to probe the mechanism of acid-catalyzed RSNO hydrolysis and its dependence on RSNO structure. This reversible reaction was forced to proceed in the denitrosation direction by trapping the nitrosating agent with HN(3). The primary RSNOs exhibited hydrolysis k(obs) values of ∼2 × 10(-4) s(-1), and the tertiary RSNO k(obs) values were an order of magnitude higher. Product analysis by HPLC revealed that the parent thiols (RSHs) were formed in 90-100% yield on 79-99% RSNO denitrosation. Possible hydrolysis mechanisms were studied computationally at the CBS-QB3 level using S-nitrosomethanethiol (MeSNO) as a model RSNO. Consideration of RSNOs as a combination of conventional R-S-N═O, zwitterionic R-S(+)═N-O(-), and RS(-)/NO(+) ion-pair resonance structures was key in understanding the mechanistic details of acid-catalyzed hydrolysis. Protonation of the S-nitroso oxygen or nitrogen activates the sulfur and nucleophilic attack by H(2)O at this atom leads to the formation of the sulfoxide-protonated N-hydroxysulfinamide, MeS(+)(OH)NHOH, with barriers of 19 and 29 kcal/mol, respectively. Proton loss and reprotonation at the nitrogen lead to secondary hydrolysis that produces the sulfinic acid MeS(═O)OH and NH(2)OH. Notably, no low-energy RSNO hydrolysis pathway for HNO release was found in the computational analysis. Protonation of the S-nitroso sulfur gives rise to NO(+) release with a low activation barrier (ΔH(double dagger)(calc) ≈ 6 kcal/mol) and the formation of MeSH in agreement with experiment. The experimental k(obs) can be expressed as K(a)k(1), where K(a) is the acid dissociation constant for protonation of the S-nitroso sulfur and k(1) the pseudo-first-order hydrolysis rate constant. Given the low �

New nanocomposites of polystyrene with polyaniline doped with lauryl sulfuric acid

NASA Astrophysics Data System (ADS)

Pud, A. A.; Nikolayeva, O. A.; Vretik, L. O.; Noskov, Yu. V.; Ogurtsov, N. A.; Kruglyak, O. S.; Fedorenko, E. A.

2017-08-01

This work is concentrated on synthesis and investigation of new core-shell nanocomposites of polystyrene (PS) with doped polyaniline (PANI). The latex containing PS nanoparticles with sizes of 15-30 nm was prepared by microemulsion polymerization of styrene in water media. The PS/PANI nanocomposites were synthesized by chemical oxidative polymerization of aniline in the PS latex media in a presence of lauryl sulfuric acid (LSA), which served as both dopant and plasticizer. The real content of PANI in the synthesized nanocomposites was determined by UV-Vis spectroscopy method. The composition of the nanocomposites and oxidation state of the doped polyaniline were characterized by FTIR spectroscopy. The core-shell morphology of the nanocomposite nanoparticles was proved by transmission and scanning electron microscopy. It was found that conductivity and thermal behavior in air of these nanocomposites not only nonlinearly depended on the doped polyaniline content but also were strongly effected both by plasticizing properties of the acid-dopant and presence of the polyaniline shell. A possibility of application of these nanocomposites as sensor materials has been demonstrated.

Oxidation of ascorbic acid by a (salen)ruthenium(VI) nitrido complex in aqueous solution.

PubMed

Wang, Qian; Man, Wai-Lun; Lam, William W Y; Lau, Tai-Chu

2014-12-25

The oxidation of ascorbic acid (H2A) by [Ru(VI)(N)(L)(MeOH)](+) in aqueous acidic solutions has the following stoichiometry: 2[Ru(VI)(N)] + 3H2A → 2[Ru(III)(NH2-HA)](+) + A. Mechanisms involving HAT/N-rebound at low pH (≤2) and nucleophilic attack at the nitride at high pH (≥5) are proposed.

Inorganic rechargeable non-aqueous cell

DOEpatents

Bowden, William L.; Dey, Arabinda N.

1985-05-07

A totally inorganic non-aqueous rechargeable cell having an alkali or alkaline earth metal anode such as of lithium, a sulfur dioxide containing electrolyte and a discharging metal halide cathode, such as of CuCl.sub.2, CuBr.sub.2 and the like with said metal halide being substantially totally insoluble in SO.sub.2 and admixed with a conductive carbon material.

Conformation of poly(γ-glutamic acid) in aqueous solution.

PubMed

Muroga, Yoshio; Nakaya, Asami; Inoue, Atsuki; Itoh, Daiki; Abiru, Masaya; Wada, Kaori; Takada, Masako; Ikake, Hiroki; Shimizu, Shigeru

2016-04-01

Local conformation and overall conformation of poly(γ-DL-glutamic acid) (PγDLGA) and poly(γ-L-glutamic acid) (PγLGA) in aqueous solution was studied as a function of degree of ionization ε by (1) H-NMR, circular dichroism, and potentiometric titration. It was clarified that their local conformation is represented by random coil over an entire ε range and their overall conformation is represented by expanded random-coil in a range of ε > ε(*) , where ε(*) is about 0.3, 0.35, 0.45, and 0.5 for added-salt concentration of 0.02M, 0.05M, 0.1M, and 0.2M, respectively. In a range of ε < ε(*) , however, ε dependence of their overall conformation is significantly differentiated from each other. PγDLGA tends to aggregate intramolecularly and/or intermolecularly with decreasing ε, but PγLGA still behaves as expanded random-coil. It is speculated that spatial arrangement of adjacent carboxyl groups along the backbone chain essentially affects the overall conformation of PγGA in acidic media. © 2015 Wiley Periodicals, Inc.

Pretreatment of eucalyptus wood chips for enzymatic saccharification using combined sulfuric acid-free ethanol cooking and ball milling.

PubMed

Teramoto, Yoshikuni; Tanaka, Noriko; Lee, Seung-Hwan; Endo, Takashi

2008-01-01

A combined sulfuric acid-free ethanol cooking and pulverization process was developed in order to achieve the complete saccharification of the cellulosic component of woody biomass, thereby avoiding the problems associated with the use of strong acid catalysts. Eucalyptus wood chips were used as a raw material and exposed to an ethanol/water/acetic acid mixed solvent in an autoclave. This process can cause the fibrillation of wood chips. During the process, the production of furfural due to an excessive degradation of polysaccharide components was extremely low and delignification was insignificant. Therefore, the cooking process is regarded not as a delignification but as an activation of the original wood. Subsequently, the activated solid products were pulverized by ball-milling in order to improve their enzymatic digestibility. Enzymatic hydrolysis experiments demonstrated that the conversion of the cellulosic components into glucose attained 100% under optimal conditions. Wide-angle X-ray diffractometry and particle size distribution analysis revealed that the scale affecting the improvement of enzymatic digestibility ranged from 10 nm to 1 microm. Field emission scanning electron microscopy depicted that the sulfuric acid-free ethanol cooking induced a pore formation by the removal of part of the lignin and hemicellulose fractions in the size range from a few of tens nanometers to several hundred nanometers. (c) 2007 Wiley Periodicals, Inc.

Supercritical Fluid Extraction of Toxic Heavy Metals and Uranium from Acidic Solutions with Sulfur-Containing Organophosphorus Reagents

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

Lin, Yuehe; Liu, Chongxuan; Wu, Hong

2003-03-02

The feasibility of using sulfur-containing organophosphorus reagents for the chelation-supercritical fluid extraction (SFE) of toxic heavy metals and uranium from acidic media was investigated. The SFE experiments were conducted in a specially-designed flow-through liquid extractor. Effective extraction of the metal ions from various acidic media was demonstrated. The effect of ligand concentration in supercritical CO{sub 2} on the kinetics of metal extraction was studied. A simplified model is used to describe the extraction kinetics and the good agreement of experimental data with the equilibrium-based model is achieved.

Quantitative trait locus analysis of seed sulfur containing amino acids in two recombinant inbred line populations of soybean

USDA-ARS?s Scientific Manuscript database

Soybean (Glycine max (L.) Merr.) is a major source of plant protein for humans and livestock. Low levels of sulfur containing amino acids (cysteine and methionine) in soybean protein is the main limitation of soybean meal as animal food. The objectives of this study were to identify and validate Q...

Biodegradation tests of mercaptocarboxylic acids, their esters, related divalent sulfur compounds and mercaptans.

PubMed

Rücker, Christoph; Mahmoud, Waleed M M; Schwartz, Dirk; Kümmerer, Klaus

2018-04-17

Mercaptocarboxylic acids and their esters, a class of difunctional compounds bearing both a mercapto and a carboxylic acid or ester functional group, are industrial chemicals of potential environmental concern. Biodegradation of such compounds was systematically investigated here, both by literature search and by experiments (Closed Bottle Test OECD 301D and Manometric Respirometry Test OECD 301F). These compounds were found either readily biodegradable or at least biodegradable to a significant extent. Some related compounds of divalent sulfur were tested for comparison (mercaptans, sulfides, disulfides). For the two relevant monofunctional compound classes, carboxylic acids/esters and mercaptans, literature data were compiled, and by comparison with structurally similar compounds without these functional groups, the influence of COOH/COOR' and SH groups on biodegradability was evaluated. Thereby, an existing rule of thumb for biodegradation of carboxylic acids/esters was supported by experimental data, and a rule of thumb could be formulated for mercaptans. Concurrent to biodegradation, abiotic processes were observed in the experiments, rapid oxidative formation of disulfides (dimerisation of monomercaptans and cyclisation of dimercaptans) and hydrolysis of esters. Some problems that compromise the reproducibility of biodegradation test results were discussed.

STABILITY OF MFI ZEOLITE-FILLED PDMS MEMBRANES DURING PERVAPORATIVE ETHANOL RECOVERY FROM AQUEOUS MIXTURES CONTAINING ACETIC ACID

EPA Science Inventory

Pervaporation is a potential process for recovering bioethanol produced from biomass fermentation. Fermentation broths contain ethanol, water, and a variety of other compounds, often including carboxylic acids. The effects of acetic acid on long-term pervaporation of aqueous et...

Acidity and hydrogen exchange dynamics of iron(II)-bound nitroxyl in aqueous solution.

PubMed

Gao, Yin; Toubaei, Abouzar; Kong, Xianqi; Wu, Gang

2014-10-20

Nitroxyl-iron(II) (HNO-Fe(II)) complexes are often unstable in aqueous solution, thus making them very difficult to study. Consequently, many fundamental chemical properties of Fe(II)-bound HNO have remained unknown. Using a comprehensive multinuclear ((1)H, (15)N, (17)O) NMR approach, the acidity of the Fe(II)-bound HNO in [Fe(CN)5(HNO)](3-) was investigated and its pK(a) value was determined to be greater than 11. Additionally, HNO undergoes rapid hydrogen exchange with water in aqueous solution and this exchange process is catalyzed by both acid and base. The hydrogen exchange dynamics for the Fe(II)-bound HNO have been characterized and the obtained benchmark values, when combined with the literature data on proteins, reveal that the rate of hydrogen exchange for the Fe(II)-bound HNO in the interior of globin proteins is reduced by a factor of 10(6). © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Conversion of Aqueous Ammonia-Treated Corn Stover to Lactic Acid by Simultaneous Saccharification and Cofermentation

NASA Astrophysics Data System (ADS)

Zhu, Yongming; Lee, Y. Y.; Elander, Richard T.

Treatment of corn stover with aqueous ammonia removes most of the structural lignin, whereas retaining the majority of the carbohydrates in the solids. After treatment, both the cellulose and hemicellulose in corn stover become highly susceptible to enzymatic digestion. In this study, corn stover treated by aqueous ammonia was investigated as the substrate for lactic acid production by simultaneous saccharification and cofermentation (SSCF). A commercial cellulase (Spezyme-CP) and Lactobacillus pentosus American Type Culture Collection (ATCC) 8041 (Spanish Type Culture Collection [CECT]-4023) were used for hydrolysis and fermentation, respectively. In batch SSCF operation, the carbohydrates in the treated corn stover were converted to lactic acid with high yields, the maximum lactic acid yield reaching 92% of the stoichiometric maximum based on total fermentable carbohydrates (glucose, xylose, and arabinose). A small amount of acetic acid was also produced from pentoses through the phosphoketolase pathway. Among the major process variables for batch SSCF, enzyme loading and the amount of yeast extract were found to be the key factors affecting lactic acid production. Further tests on nutrients indicated that corn steep liquor could be substituted for yeast extract as a nitrogen source to achieve the same lactic acid yield. Fed-batch operation of the SSCF was beneficial in raising the concentration of lactic acid to a maximum value of 75.0 g/L.

Sulfur dioxide leaching of spent zinc-carbon-battery scrap

NASA Astrophysics Data System (ADS)

Avraamides, J.; Senanayake, G.; Clegg, R.

Zinc-carbon batteries, which contain around 20% zinc, 35% manganese oxides and 10% steel, are currently disposed after use as land fill or reprocessed to recover metals or oxides. Crushed material is subjected to magnetic separation followed by hydrometallurgical treatment of the non-magnetic material to recover zinc metal and manganese oxides. The leaching with 2 M sulfuric acid in the presence of hydrogen peroxide recovers 93% Zn and 82% Mn at 25 °C. Alkaline leaching with 6 M NaOH recovers 80% zinc. The present study shows that over 90% zinc and manganese can be leached in 20-30 min at 30 °C using 0.1-1.0 M sulfuric acid in the presence of sulfur dioxide. The iron extraction is sensitive to both acid concentration and sulfur dioxide flow rate. The effect of reagent concentration and particle size on the extraction of zinc, manganese and iron are reported. It is shown that the iron and manganese leaching follow a shrinking core kinetic model due to the formation of insoluble metal salts/oxides on the solid surface. This is supported by (i) the decrease in iron and manganese extraction from synthetic Fe(III)-Mn(IV)-Zn(II) oxide mixtures with increase in acid concentration from 1 M to 2 M, and (ii) the low iron dissolution and re-precipitation of dissolved manganese and zinc during prolonged leaching of battery scrap with low sulfur dioxide.

Homogeneous freezing of single sulfuric and nitric acid solution drops levitated in an acoustic trap

NASA Astrophysics Data System (ADS)

Diehl, Karoline; Ettner-Mahl, Matthias; Hannemann, Anke; Mitra, Subir K.

2009-10-01

The freezing temperatures of single supercooled drops of binary and ternary sulfuric and nitric acid solutions were measured while varying the acid concentration. An acoustic levitator was used which allows to freely suspend single solution drops in air without electrical charges thereby avoiding any electrical influences which may affect the freezing process. The drops of typically 500 µm in radius were monitored by a video camera during cooling cycles down to - 85 °C to simulate the upper tropospheric and stratospheric temperature range. The present data confirm that liquid solution droplets can be supercooled far below the equilibrium melting point by approximately 35 °C. They follow the general trend of the expected freezing temperatures for homogeneous ice nucleation.

Sulfur-doped porous reduced graphene oxide hollow nanosphere frameworks as metal-free electrocatalysts for oxygen reduction reaction and as supercapacitor electrode materials.

PubMed

Chen, Xi'an; Chen, Xiaohua; Xu, Xin; Yang, Zhi; Liu, Zheng; Zhang, Lijie; Xu, Xiangju; Chen, Ying; Huang, Shaoming

2014-11-21

Chemical doping with foreign atoms is an effective approach to significantly enhance the electrochemical performance of the carbon materials. Herein, sulfur-doped three-dimensional (3D) porous reduced graphene oxide (RGO) hollow nanosphere frameworks (S-PGHS) are fabricated by directly annealing graphene oxide (GO)-encapsulated amino-modified SiO2 nanoparticles with dibenzyl disulfide (DBDS), followed by hydrofluoric acid etching. The XPS and Raman spectra confirmed that sulfur atoms were successfully introduced into the PGHS framework via covalent bonds. The as-prepared S-PGHS has been demonstrated to be an efficient metal-free electrocatalyst for oxygen reduction reaction (ORR) with the activity comparable to that of commercial Pt/C (40%) and much better methanol tolerance and durability, and to be a supercapacitor electrode material with a high specific capacitance of 343 F g(-1), good rate capability and excellent cycling stability in aqueous electrolytes. The impressive performance for ORR and supercapacitors is believed to be due to the synergistic effect caused by sulfur-doping enhancing the electrochemical activity and 3D porous hollow nanosphere framework structures facilitating ion diffusion and electronic transfer.

Visualization of Imbalances in Sulfur Assimilation and Synthesis of Sulfur-Containing Amino Acids at the Single-Cell Level

PubMed Central

Hoffmann, Kristina; Grünberger, Alexander; Lausberg, Frank; Bott, Michael

2013-01-01

We describe genetically encoded sensors which transmit elevated cytosolic concentrations of O-acetyl serine (OAS) and O-acetyl homoserine (OAH)—intermediates of l-cysteine and l-methionine synthesis—into an optical output. The sensor pSenOAS3 elicits 7.5-fold-increased fluorescence in cultures of a Corynebacterium glutamicum strain that excrete l-cysteine. Determination of the cytosolic OAS concentration revealed an increase to 0.13 mM, whereas the concentration in the reference strain was below the detection limit, indicating that incorporation of assimilatory sulfur is limited in the strain studied. In another strain, overexpression of metX encoding homoserine acetyltransferase resulted in an 8-fold increase in culture fluorescence at a cytosolic OAH concentration of 0.76 mM. We also assayed for consequences of extracellular sulfur supply and observed a graded fluorescence increase at decreasing sulfur concentrations below 400 μM. Overall, this demonstrates the usefulness of the sensors for monitoring intracellular sulfur availability. The sensors also enable monitoring at the single-cell level, and since related and close homologs of the transcription factor used in the constructed sensors are widespread among bacteria, this technology offers a new possibility of assaying in vivo for sulfur limitation and of doing this at the single-cell level. PMID:23995919

Visualization of imbalances in sulfur assimilation and synthesis of sulfur-containing amino acids at the single-cell level.

PubMed

Hoffmann, Kristina; Grünberger, Alexander; Lausberg, Frank; Bott, Michael; Eggeling, Lothar

2013-11-01

We describe genetically encoded sensors which transmit elevated cytosolic concentrations of O-acetyl serine (OAS) and O-acetyl homoserine (OAH)-intermediates of l-cysteine and l-methionine synthesis-into an optical output. The sensor pSenOAS3 elicits 7.5-fold-increased fluorescence in cultures of a Corynebacterium glutamicum strain that excrete l-cysteine. Determination of the cytosolic OAS concentration revealed an increase to 0.13 mM, whereas the concentration in the reference strain was below the detection limit, indicating that incorporation of assimilatory sulfur is limited in the strain studied. In another strain, overexpression of metX encoding homoserine acetyltransferase resulted in an 8-fold increase in culture fluorescence at a cytosolic OAH concentration of 0.76 mM. We also assayed for consequences of extracellular sulfur supply and observed a graded fluorescence increase at decreasing sulfur concentrations below 400 μM. Overall, this demonstrates the usefulness of the sensors for monitoring intracellular sulfur availability. The sensors also enable monitoring at the single-cell level, and since related and close homologs of the transcription factor used in the constructed sensors are widespread among bacteria, this technology offers a new possibility of assaying in vivo for sulfur limitation and of doing this at the single-cell level.