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Sample records for organic ammonium ions

  1. Molecular recognition of organic ammonium ions in solution using synthetic receptors

    PubMed Central

    Späth, Andreas

    2010-01-01

    Summary Ammonium ions are ubiquitous in chemistry and molecular biology. Considerable efforts have been undertaken to develop synthetic receptors for their selective molecular recognition. The type of host compounds for organic ammonium ion binding span a wide range from crown ethers to calixarenes to metal complexes. Typical intermolecular interactions are hydrogen bonds, electrostatic and cation–π interactions, hydrophobic interactions or reversible covalent bond formation. In this review we discuss the different classes of synthetic receptors for organic ammonium ion recognition and illustrate the scope and limitations of each class with selected examples from the recent literature. The molecular recognition of ammonium ions in amino acids is included and the enantioselective binding of chiral ammonium ions by synthetic receptors is also covered. In our conclusion we compare the strengths and weaknesses of the different types of ammonium ion receptors which may help to select the best approach for specific applications. PMID:20502608

  2. Formation of nitrate and ammonium ions in titanium dioxide mediated photocatalytic degradation of organic compounds containing nitrogen atoms

    SciTech Connect

    Low, G.K.-C.; McEvoy, S.R.; Matthews, R.W. )

    1991-03-01

    The photocatalytic oxidation of a related series of primary, secondary, and tertiary amines and other nitrogen- and sulfur-containing organic compounds over a UV-illuminated film of TiO{sub 2} has been studied. The compounds were as follows: n-pentylamine, piperidine, pyridine, phenylalanine, desipramine, thioridazine, penicillamine, isosorbide dinitrate, 4-nitrocatechol, 2,4-dinitrophenol, cyclophosphamide, 5-fluorouracil, atrazine, ethylenediaminetetracetic acid, and tetrabutylammonium phosphate. Both ammonium and nitrate ions were formed. The relative concentration of the two ions depended on the nature of the nitrogen in a compound, but was also influenced by the illumination time and concentration of the solute. It was found that for n-pentylamine, piperidine and pyridine, the rate of formation of ammonium ions was n-pentylamine {much gt} pyridine > piperidine. The order of rates of nitrate formation was pyridine = piperidine {much gt} pentylamine. For n-pentylamine the rate of formation of ammonium ions was {approximately}100 times that of nitrate.

  3. Extraction of urea and ammonium ion

    NASA Technical Reports Server (NTRS)

    Anselmi, R. T.; Husted, R. R.; Schulz, J. R.

    1977-01-01

    Water purification system keeps urea and ammonium ion concentration below toxic limits in recirculated water of closed loop aquatic habitat. Urea is first converted to ammonium ions and carbon dioxide by enzygmatic action. Ammonium ions are removed by ion exchange. Bioburden is controlled by filtration through 0.45 micron millipore filters.

  4. Organic Modification of a Layered Silicate by Co-Ion Exchange of an Alkyl Ammonium and a Mono-Protonated Diamine

    NASA Technical Reports Server (NTRS)

    Campbell, Sandi G. (Inventor)

    2004-01-01

    Co-Ion exchange of the interlayer cations of a layered silicate with a mono-protonated aromatic diamine and an alkyl ammonium ion into the silicate galleries. The presence of the alkyl ammonium ion provides low oligomer melt viscosity during processing. The presence of the diamine allows chemical reaction between the silicate surface modification and the monomers. This reaction strengthens the polymer silicate interface, and ensures irreversible separation of the individual silicate layers. Improved polymer thermal oxidative stability and mechanical properties are obtained.

  5. Preferential uptake of ammonium ions by zinc ferrocyanide

    NASA Technical Reports Server (NTRS)

    Braterman, P. S.; Arrhenius, G.; Hui, S.; Paplawsky, W.; Miller, S. L. (Principal Investigator)

    1995-01-01

    The concentration of ammonia from dilute aqueous solution could have facilitated many prebiotic reactions. This may be especially true if this concentration involves incorporation into an organized medium. We have shown that (unlike iron(III) ferrocyanide) zinc ferrocyanide,Zn2Fe(CN)6 xH2O, preferentially takes up ammonium ions from 0.01 M NH4Cl to give the known material Zn3(NH4)2[Fe(CN)6]2 xH2O, even in the presence of 0.01 M KCl. KCl alone gave Zn3K2[Fe(CN)6]2 xH2O. Products were characterized by elemental (CHN) analysis and powder X-ray diffraction (XRD). We attribute the remarkable specificity for the ammonium ion to the open framework of the product, which offers enough space for hydrogen-bonded ammonium ions, and infer that other inorganic materials with internal spaces rich in water may show a similar preference.

  6. Ammonium Ion Currents in the Squid Giant Axon

    PubMed Central

    Binstock, Leonard; Lecar, Harold

    1969-01-01

    Voltage-clamp studies on intact and internally perfused squid giant axons demonstrate that ammonium can substitute partially for either sodium or potassium. Ammonium carries the early transient current with 0.3 times the permeability of sodium and it carries the delayed current with 0.3 times the potassium permeability. The conductance changes observed in voltage clamp show approximately the same time course in ammonium solutions as in the normal physiological solutions. These ammonium ion permeabilities account for the known effects of ammonium on nerve excitability. Experiments with the drugs tetrodotoxin (TTX) and tetraethyl ammonium chloride (TEA) demonstrate that these molecules block the early and late components of the current selectively, even when both components are carried by the same ion, ammonium. PMID:5767336

  7. Contribution of ammonium ions to the lethality and antimetamorphic effects of ammonium perchlorate.

    PubMed

    Goleman, Wanda L; Carr, James A

    2006-04-01

    Ammonium perchlorate (AP) is a widespread military waste product in the United States and is a potent thyroid function disruptor in all vertebrates tested thus far. To determine the relative contribution of ammonium ions to the toxicity of AP, we exposed embryonic and larval Xenopus laevis to various concentrations of sodium perchlorate (SP) or ammonium chloride (AC). Ammonium perchlorate was significantly more lethal than SP; 5-d LC50s were 83 and 2,780 mg/L, respectively. To determine whether ammonium ions contribute to the antithyroid effects of AP, we exposed embryonic and larval X. laevis to two sublethal, environmentally relevant concentrations of AP or identical concentrations of AC or SP. At the smaller concentration, only AP delayed metamorphosis and reduced hindlimb growth. Sodium perchlorate and AP, but not AC, prevented metamorphosis and reduced hindlimb growth at the greater concentration. Although AP was slightly more effective in reducing outward manifestations of thyroid disruption, both perchlorate salts, unlike AC, caused profound histopathologic changes in the thyroid. Exposure to the higher concentration of either perchlorate salt produced a feminizing effect, resulting in a skewed sex ratio. We conclude that ammonium ions contribute significantly to the toxicity of AP but not to the direct antithyroid effects of perchlorate.

  8. Ammonium and sulfate ion release of histamine from lung fragments.

    PubMed

    Charles, J M; Menzel, D B

    1975-06-01

    In vitro studies with guinea pig lung fragments incubated with 10- to 200-mM concentrations of ammonium ion demonstrated the release of substanial quantities of histamine. Of the anions tested with ammonium ion, sulfate was the most potent, while nitrate and acetate ions were of intermediate potency and chloride was less potent. An osmotic effect is unlikely since equal concentrations of sodium chloride failed to release histamine. Isoproterenol, known to decrease anaphylactic histamine release, and acetycholine, known to increase histamine release, had no effect on the ammonium sulfate-mediated release of histamine. N-6 2'-O-Dibutyryladenosine 3',5' monophosphate (dibutyryl c-AMP) was also ineffective. These studies suggest that the inhalation irritation associated with certain sulfate and other salts, may be a function of their ability to release histamine in the presence of amonium ion.

  9. Deliquescence behavior of organic/ammonium sulfate aerosol

    NASA Astrophysics Data System (ADS)

    Brooks, Sarah D.; Wise, Matthew E.; Cushing, Melinda; Tolbert, Margaret A.

    2002-10-01

    Recent studies have shown that tropospheric aerosols composed of internal mixtures of organics with sulfates are quite common with the organic composing up to 50% of the particle mass. The influences of the organics on the chemical and physical properties of the aerosol are not known. In this paper, we report the solubility of a series of dicarboxylic acids in saturated ammonium sulfate solution as a function of temperature. We also report the deliquescence relative humidity (DRH) of the pure dicarboxylic acids and of mixtures of dicarboxylic acids with ammonium sulfate. For the systems studied, we find that the presence of water-soluble dicarboxylic acids caused deliquescence to occur at a lower relative humidity (RH) than pure ammonium sulfate. In contrast, the less soluble dicarboxylic acids had no measurable effect on the deliquescence relative humidity of ammonium sulfate.

  10. Molecular determinants for binding of ammonium ion in the ammonia transporter AmtB-A quantum chemical analysis.

    PubMed

    Liu, Yuemin; Hu, Xiche

    2006-02-02

    The transport of ammonium across the cell membrane represents an important biological process in all living organisms. The mechanisms for ammonium translocation were analyzed by computer simulations based on first principles. Intermolecular interaction energies between the differentially methylated ammonium and the ammonium channel protein AmtB were calculated by means of the supermolecular approach at the MP2/6-311+G* level based on the high-resolution crystal structures of ligand-bound protein complexes. Our analysis attributes the molecular determinants for protein-ligand recognition in ammonium transporter AmtB to the aromatic cage formed by three aromatic residues Phe103, Phe107, and Trp148, as well as Ser219. The former residues are involved in cation-pi interactions with the positively charged methylated ammoniums. The latter residue acts as a hydrogen bond acceptor to ammonium. Thus, this work provides directly the missing evidence for the hypothesized role played by the wider vestibule site of AmtB at the periplasmic side of the membrane in "recruiting" NH(4)(+) or methylammonium ions as proposed by Khademi et al. (Science 2004, 305, 1587). In addition, a hybrid quantum mechanics/molecular mechanics scheme was applied to optimize the structures of differentially methylated ammoniums in the AmtB protein, which generated structural and energetic data that provide a satisfactory explanation to the experimental observation that tetramethylammonium is not inhibitory to conducting ammonium and methylammonium in the ammonium transport channel.

  11. Liquid-liquid distribution of ion associates of tetrabromoindate(III) with quaternary ammonium counter ions.

    PubMed

    Yamamoto, K; Matsumoto, A

    1997-11-01

    The solvent extraction of an ion associate of tetrabromoindate(III) ion, InBr(-)(4), with quaternary ammonium cations (Q(+)) has been studied. The extraction constant (K(ex)) were determined for the ion associates of InBr(-)(4) with Q(+) between an aqueous phase and several organic phases (chloroform, chlorobenzene, benzene and toluene). A linear relationship was found between log K(ex) and the total number of carbon atoms in Q(+); from the slope of the lines, the contribution of a methylene group to log K(ex) was calculated to be 0.91 for the chloroform extraction system and 0.52 for the other extraction systems. The extractability with alkyltrimethylammonium cations was larger than that with symmetrical tetraalkylammonium cations and the mean difference in log K(ex) for two cations (one of each type) with the same number of carbon atoms was about 1.3. From the extraction constant obtained, the extractability of InBr(-)(4) among metal-halogeno complex anions was in the order TlBr(-)(4) > BiI(-)(4) > AuBr(-)(4) > AuCl(-)(4) > TlCl(-)(4) > InBr(-)(4) > CuCl(-)(2).

  12. Stepwise determination of quaternary ammonium salts and aromatic amines in pharmaceuticals by ion association titration.

    PubMed

    Sakai, T

    2001-12-01

    A stepwise titrimetric method has been developed for the simultaneous determination of pharmaceutical quaternary ammonium salts (R4N+) and aromatic amines (R3N). The method is based on the solvent extraction of R4N+ and R3NH+ with an ion association reagent. Sodium tetrakis(4-fluorophenyl)borate and sodium tetraphenylborate were used as titrants and potassium tetrabromophenolphthalein ethyl ester (TBPE) was used as an indicator. The ion associate which formed between R4N+ ion and TBPE made a blue color in 1,2-dichloroethane, while the ion associate formed between R3NH+ and TBPE showed a red-violet one. Sample solutions containing quaternary ammonium and/or amine compounds were titrated with sodium tetrakis(4-fluorophenyl)borate or sodium tetraphenylborate. When one drop of excess titrant was added, the color of the organic phase turned from blue or red-violet to yellow at the equivalence point. On the other hand, in the mixture of R4N+ and R3N, the color changed from blue to red-violet at the first equivalence point, and then its color turned to yellow at the second equivalence point. The quaternary ammonium compound and aromatic amine in pharmaceuticals could be simultaneously and successfully determined by the proposed titration method.

  13. Mixed ternary ion associate formation between xanthene dye, cinchona-alkaloid and quaternary ammonium ion and its application to the determination of trace amounts of quaternary ammonium salts in pharmaceuticals.

    PubMed

    Sakai, Tadao; Hirose, Akihiko

    2003-01-02

    Xanthene dyes such as eosin and tetraiodofluorescein form 1:2 ion associates with quaternary ammonium ions at pH 7-9; however, the development of color in the organic solvent is poor. When a quaternary ammonium salt is added in the extractable 1:2 associate formed between a xanthene dye and a cinchona-alkaloid in the neutral media, a mixed ternary ion associate (xanthene dye:cinchona-alkaloid:quaternary ammonium ion=1:1:1) is formed. Its extractability is enhanced due to the more bulky associate formation. The ion association caused by addition of cinchona-alkaloids is unique. Of the cinchona-alkaloids, quinidine and cinchonidine with tetraiodofluorescein show excellent effects on sensitivity and extractability. Eosin and tetraiodofluorescein are useful as ion association reagents in the ion associate formation. The apparent molar absorptivities are about 1x10(5) l mol(-1) cm(-1) and the calibration range for quaternary ammonium salt is from 2.5x10(-7) to 1.5x10(-6) M. The proposed method is applicable to the selective and sensitive determination of cetylpyridinium chloride, berberine chloride and benzethonium chloride in pharmaceuticals.

  14. AMMONIUM AND FORMATE IONS IN INTERSTELLAR ICE ANALOGS

    SciTech Connect

    Galvez, Oscar; Mate, Belen; Herrero, Victor J.; Escribano, Rafael

    2010-11-20

    The so-called hyperquenching technique has been applied to generate water ices containing ammonium and formate ions by sudden freezing of droplets of NH{sub 4}Cl, NH{sub 4}COOH, and NaCOOH solutions. Salt deposits were obtained after heating the ices to 210 K to sublimate all water content. All stages are controlled by IR transmission spectroscopy. The NH{sub 4} {sup +} bands are very much broadened and smeared in the frozen droplets, but stand out strongly when water is eliminated. This fact hints toward the difficulty in ascertaining the presence of this species in astrophysical water-containing ices. Vapor-deposited ices of NH{sub 3}/HCOOH and H{sub 2}O/NH{sub 3}/HCOOH mixtures have also been studied for comparison. HCOO{sup -} and NH{sub 4} {sup +} ions are found to be formed in small proportion even at the lowest temperature, 14 K. By thermal processing, their IR bands become stronger, and at 210 K, after water sublimation, they yield IR spectra similar to those obtained from hyperquenched samples. The observations are interpreted in terms of the varying ion arrangement within the solids along the warming process. A direct comparison to laboratory spectra of irradiated samples, as performed by other groups, is not straightforward.

  15. Evidence of ammonium ion-exchange properties of natural bentonite and application to ammonium detection.

    PubMed

    Zazoua, A; Kazane, I; Khedimallah, N; Dernane, C; Errachid, A; Jaffrezic-Renault, N

    2013-12-01

    Ammonium exchange with hybrid PVC-bentonite (mineral montmorillonite clay) thin film was revealed using FTIR spectroscopy, EDX, cyclic voltammetry and electrochemical impedance spectroscopy. The effect of ammonium exchange on the charge transfer resistance of PVC-bentonite hybrid thin film was attributed to a modification of the intersheet distance and hydration of bentonite crystals. The obtained impedimetric ammonium sensor shows a linear range of detection from 10(-4)M to 1M and a detection limit around 10(-6)M.

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

    PubMed

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

    2016-12-06

    Dissolved inorganic salts influence the partitioning of organic compounds into the aqueous phase. This influence is especially significant in atmospheric aerosol, which usually contains large amounts of ions, including sodium, ammonium, chloride, sulfate, and nitrate. However, empirical data on this salt effect are very sparse. Here, the partitioning of numerous organic compounds into solutions of Na2SO4, NH4Cl, and NH4NO3 was measured and compared with existing data for NaCl and (NH4)2SO4. Salt mixtures were also tested to establish whether the salt effect is additive. In general, the salt effect showed a decreasing trend of Na2SO4 > (NH)2SO4 > NaCl > NH4Cl > NH4NO3 for the studied organic compounds, implying the following relative strength of the salt effect of individual anions: SO4(2-) > Cl(-) > NO3(-) and of cations: Na(+) > NH4(+). The salt effect of different salts is moderately correlated. Predictive models for the salt effect were developed based on the experimental data. The experimental data indicate that the salt effect of mixtures may not be entirely additive. However, the deviation from additivity, if it exists, is small. Data of very high quality are required to establish whether the effect of constituent ions or salts is additive or not.

  17. Conductometric determination of ammonium ion with a mobile drop.

    PubMed

    Jaikang, Pheeraya; Grudpan, Kate; Kanyanee, Tinakorn

    2015-01-01

    A mobile drop based approach was utilized for the conductometric determination of aqueous ammonium ion. A liquid drop was manipulated by gravity to remain or move out of a conductivity measurement zone located on a hydrophobic path. A dilute sulfuric acid drop functioned as a micro gas absorber. Gaseous NH3 was liberated from a sample containing NH4(+) by adding NaOH and purged to flow over the absorber drop. As H(+) in the absorber drop was converted to NH4(+), the conductivity decreased. The rate of the conductivity decrease thus ultimately depended on the NH4(+) concentration in the sample. While the sample could be complex, the liberation of NH3 gas essentially freed the analyte of interest from the matrix and allowed the use of an otherwise nonselective detector. The system was applied to the determination of NH4(+) in some natural waters without prior filtration; the results agreed well with those from a manual indophenol blue method. The approach exhibited a limit of detection (LOD) of 5 μM and a relative standard deviation (RSD) of<5%. The mobile drop gave a constant volume of the gas absorbing solution and provided a cost-effective and simple analytical platform.

  18. Sorption of aromatic ionizable organic compounds to montmorillonites modified by hexadecyltrimethyl ammonium and polydiallyldimethyl ammonium.

    PubMed

    Xu, Huaizhou; Wan, Yuqiu; Li, Hui; Zheng, Shourong; Zhu, Dongqiang

    2011-01-01

    Environmental residues of aromatic ionizable organic compounds (AIOCs) have received considerable attention due to their potential human health and ecological risks. The main objective of this study was to investigate the key factors and mechanisms controlling sorption of a series of anionic and zwitterionic AIOCs (two aromatic sulfonates, 4-methyl-2,6-dinitrophenol, tetracycline, sulfamethoxazole, and tannic acid) to montmorillonites modified with hexadecyltrimethyl ammonium (HDTMA) and polydiallyldimethyl ammonium (PDADMA). Compared with naphthalene (a nonpolar and nonionic solute), all AIOCs showed stronger sorption (the sorbent-to-solution distribution coefficient was in the order of 10-10 L kg) to the two organoclays in spite of the much lower hydrophobicity, indicating the predominance of electrostatic interaction in sorption. The proposed electrostatic mechanism of the tested AIOCs was supported by the pH dependency of sorption to the two organoclays. The two organoclays manifested weaker sorption affinity but faster sorption kinetics for bulky AIOCs than commercial activated carbon, resulting from the high accessibility of sorption sites in the open, ordered clay interlayer. The findings of this study highlight the potential of using HDTMA- and PDADMA-exchanged montmorillonites as effective sorbents for AIOCs in water and wastewater treatments.

  19. Noncovalent Complexation of Monoamine Neurotransmitters and Related Ammonium Ions by Tetramethoxy Tetraglucosylcalix[4]arene

    NASA Astrophysics Data System (ADS)

    Torvinen, Mika; Kalenius, Elina; Sansone, Francesco; Casnati, Alessandro; Jänis, Janne

    2012-02-01

    The noncovalent complexation of monoamine neurotransmitters and related ammonium and quaternary ammonium ions by a conformationally flexible tetramethoxy glucosylcalix[4]arene was studied by electrospray ionization Fourier transform ion cyclotron resonance (ESI-FTICR) mass spectrometry. The glucosylcalixarene exhibited highest binding affinity towards serotonin, norepinephrine, epinephrine, and dopamine. Structural properties of the guests, such as the number, location, and type of hydrogen bonding groups, length of the alkyl spacer between the ammonium head-group and the aromatic ring structure, and the degree of nitrogen substitution affected the complexation. Competition experiments and guest-exchange reactions indicated that the hydroxyl groups of guests participate in intermolecular hydrogen bonding with the glucocalixarene.

  20. Adsorption of ammonium ion by coconut shell-activated carbon from aqueous solution: kinetic, isotherm, and thermodynamic studies.

    PubMed

    Boopathy, Ramasamy; Karthikeyan, Sekar; Mandal, Asit Baran; Sekaran, Ganesan

    2013-01-01

    Ammonium ions are one of the most encountered nitrogen species in polluted water bodies. High level of ammonium ion in aqueous solution imparts unpleasant taste and odor problems, which can interfere with the life of aquatics and human population when discharged. Many chemical methods are developed and being used for removal of ammonium ion from aqueous solution. Among various techniques, adsorption was found to be the most feasible and environmentally friendly with the use of natural-activated adsorbents. Hence, in this study, coconut shell-activated carbon (CSAC) was prepared and used for the removal of ammonium ion by adsorption techniques. Ammonium chloride (analytical grade) was purchased from Merck Chemicals for adsorption studies. The CSAC was used to adsorb ammonium ions under stirring at 100 rpm, using orbital shaker in batch experiments. The concentration of ammonium ion was estimated by ammonia distillate, using a Buchi distillation unit. The influence of process parameters such as pH, temperature, and contact time was studied for adsorption of ammonium ion, and kinetic, isotherm models were validated to understand the mechanism of adsorption of ammonium ion by CSAC. Thermodynamic properties such as ∆G, ∆H, and ∆S were determined for the ammonium adsorption, using van't Hoff equation. Further, the adsorption of ammonium ion was confirmed through instrumental analyses such as SEM, XRD, and FTIR. The optimum conditions for the effective adsorption of ammonium ion onto CSAC were found to be pH 9.0, temperature 283 K, and contact time 120 min. The experimental data was best followed by pseudosecond order equation, and the adsorption isotherm model obeyed the Freundlich isotherm. This explains the ammonium ion adsorption onto CSAC which was a multilayer adsorption with intraparticle diffusion. Negative enthalpy confirmed that this adsorption process was exothermic. The instrumental analyses confirmed the adsorption of ammonium ion onto CSAC.

  1. Removal of ammonium and nitrate ions from mine effluents by membrane technology

    SciTech Connect

    Awadalla, F.T.; Striez, C.; Lamb, K. )

    1994-02-01

    Ammonium and nitrate ions could be removed from synthetic and actual mine effluents by using nanofiltration (NF) and reverse osmosis (RO) membranes. RO membranes were found more effective in removing these ions (>99% for NH[sub 4][sup +] and about 97% for NO[sup [minus

  2. Determination of ammonium in a buddingtonite sample by ion-chromatography

    USGS Publications Warehouse

    Klock, P.R.; Lamothe, P.J.

    1986-01-01

    An ion-chromatographic method for the direct determination of ammonium, potassium, and sodium in geologic materials is described. Samples are decomposed with a mixture of hydrofluoric and hydrochloric acids in a sealed polycarbonate bottle heated in a microwave oven. The ion-chromatograph separates the cations and determines them by conductivity measurement. The ammonium concentrations thus determined have been verified by use of an ammonia-specific electrode. A total of 32 analyses of ammonium salts by both techniques showed an average error of -4%, with a relative standard deviation (RSD) of 6%. The ammonium concentrations found in a buddingtonite sample had an RSD of 2.2% and their mean agreed with that obtained by the Kjeldahl method. By use of the prescribed dilution of the sample, detection limits of 0.1% can be achieved for all three cations. ?? 1986.

  3. Upgrading fertilizer production wastewater effluent quality for ammonium discharges through ion exchange with clinoptilolite.

    PubMed

    Beler-Baykal, B; Allar, A D

    2008-06-01

    It had previously been shown that ammonium selective natural zeolite clinoptilolite may be used successfully as an ion exchanger for ammonium removal and nitrogen control from domestic wastewater. The process had been reported to be acceptable either by itself alone or as an upgrade. In this work, the possibility of using clinoptilolite for ammonium removal from fertilizer production wastewater was investigated. The fertilizer plant under consideration was rather a non-typical one with a lower ammonium strength than what is normally expected, and a variable effluent concentration. Batch experiments were performed to assess the capacity of clinoptilolite towards ammonium removal from an industrial wastewater at two different pHs. Flow experiments for the characterization of system behavior under continuous feeding conditions at different contact times were conducted for breakthrough analysis. Both real and simulated fertilizer wastewater samples were investigated and the results have shown that the real one may successfully be represented by the simulated one. Experimental results have shown that surface capacities exceeding 14 mg ammonium g(-1) clinoptilolite could be attained, complete removal of ammonium may be achieved with empty bed contact times of 10 min or higher and ion exchange with clinoptilolite could be used successfully to comply with the effluent standards given for the fertilizer plant.

  4. Extraction of Nb(v) by quaternary ammonium-based solvents: toward organic hexaniobate systems.

    PubMed

    Deblonde, Gauthier J-P; Chagnes, Alexandre; Roux, Marie-Aude; Weigel, Valérie; Cote, Gérard

    2016-12-06

    Solvent extraction of Nb(v) from alkaline aqueous media using quaternary ammonium solutions, especially Aliquat® 336 diluted in an aliphatic diluent, was investigated. The hexaniobate ions (HxNb6O19(x-8)) were extracted into the organic phase with very high yields at room temperature and within a few minutes, affording easy access to organic solutions of hexaniobates. Several parameters were found to influence the extraction of HxNb6O19(x-8) including the nature and concentration of alkali cations, confirming subtle effects previously described for polyoxoniobates such as ion-pairing with alkali ions. The extraction of HxNb6O19(x-8) with Aliquat® 336 is also influenced if competing anions are present in the aqueous phase (NO3(-), Cl(-), C2O4(2-), SO4(2-) and CO3(2-)) and varies with the pH mainly due to the competitive extraction of hydroxide ions at high pH. The co-extraction of sodium ions with HxNb6O19(x-8) was observed as well as the co-extraction of water molecules, suggesting a self-association of the extractant. The proposed liquid-liquid extraction generic system paves the way for innovative niobium (and potentially tantalum) hydrometallurgical processes and it may also afford more direct routes for exploring the chemistry of hexaniobates in organic solvents.

  5. Growth of Ammonium Bisulfate Clusters by Adsorption of Oxygenated Organic Molecules

    DOE PAGES

    DePalma, Joseph W.; Wang, Jian; Wexler, Anthony S.; ...

    2015-10-21

    Quantum chemical calculations were employed to model the interactions of the [(NH4+)4(HSO4-)4] ammonium bisulfate cluster with one or more molecular products of monoterpene oxidation. A strong interaction was found between the bisulfate ion of the cluster and a carboxylic acid, aldehyde or ketone functionality of the organic molecule. Free energies of adsorption for carboxylic acids were in the -70 to -73 kJ/mol range, while those for aldehydes and ketones were in the -46 to -50 kJ/mol range. These values suggest that a small ambient ammonium bisulfate cluster, such as the [(NH4+)4(SO4-)4] cluster, is able to adsorb an oxygenated organic molecule.more » Although adsorption of the first molecule is highly favorable, adsorption of subsequent molecules is not, suggesting that sustained uptake of organic molecules does not occur, and thus is not a pathway for continuing growth of the cluster. This result is consistent with ambient measurements showing that particles below ~1 nm grow slowly, while those above 1 nm grow at an increasing rate presumably due to a lower surface energy barrier enabling the uptake of organic molecules. This work provides insight into the molecular level interactions which affect sustained cluster growth by uptake of organic molecules.« less

  6. Growth of Ammonium Bisulfate Clusters by Adsorption of Oxygenated Organic Molecules

    SciTech Connect

    DePalma, Joseph W.; Wang, Jian; Wexler, Anthony S.; Johnston, Murray V.

    2015-10-21

    Quantum chemical calculations were employed to model the interactions of the [(NH4+)4(HSO4-)4] ammonium bisulfate cluster with one or more molecular products of monoterpene oxidation. A strong interaction was found between the bisulfate ion of the cluster and a carboxylic acid, aldehyde or ketone functionality of the organic molecule. Free energies of adsorption for carboxylic acids were in the -70 to -73 kJ/mol range, while those for aldehydes and ketones were in the -46 to -50 kJ/mol range. These values suggest that a small ambient ammonium bisulfate cluster, such as the [(NH4+)4(SO4-)4] cluster, is able to adsorb an oxygenated organic molecule. Although adsorption of the first molecule is highly favorable, adsorption of subsequent molecules is not, suggesting that sustained uptake of organic molecules does not occur, and thus is not a pathway for continuing growth of the cluster. This result is consistent with ambient measurements showing that particles below ~1 nm grow slowly, while those above 1 nm grow at an increasing rate presumably due to a lower surface energy barrier enabling the uptake of organic molecules. This work provides insight into the molecular level interactions which affect sustained cluster growth by uptake of organic molecules.

  7. Phosphate-dependent glutaminase in enterocyte mitochondria and its regulation by ammonium and other ions.

    PubMed

    Masola, B; Zvinavashe, E

    2003-06-01

    The effects of ammonium and other ions on phosphate dependent glutaminase (PDG) activity in intact rat enterocyte mitochondria were investigated. Sulphate and bicarbonate activated the enzyme in absence and presence of added phosphate. In presence of 10 mM phosphate, ammonium at concentrations <1 mM inhibited the enzyme. This inhibition was reversed by increased concentration of phosphate or sulphate. The inhibition of PDG by ammonium in presence of 10 mM phosphate was biphasic with respect to glutamine concentration, its effect being through a lowering of V(max) at glutamine concentration of Ammonium and bicarbonate ions may therefore be important physiological regulators of PDG. It is suggested that phosphate and other polyvalent ions may function by preventing product inhibition of the enzyme through promotion of PDG dimer formation. The dimerized enzyme may have a high affinity for glutamine and reduced sensitivity to inhibition by ammonium ions.

  8. Hybrid organic-inorganic crystals based on ammonium dihydrogen phosphate and ammonium salicylate

    NASA Astrophysics Data System (ADS)

    Voronov, A. P.; Salo, V. I.; Puzikov, V. M.; Babenko, G. N.; Roshal, A. D.; Tkachenko, V. F.

    2011-11-01

    ADP-NH 4Sal hybrid crystals are grown from aqueous solutions. The influence of the acidity of the mixed solution on the conditions of co-crystallization of the components is studied. The spectral and scintillation characteristics are determined. Co-crystallization of ammonium salicylate (NH 4Sal) and ammonium dihydrogen phosphate (ADP, NH 4H 2PO 4) is shown to be feasible, the structure of the doping addition being defined by the solution рН. In basic and weak acidic media the hybrid crystals ADP:NH 4Sal are formed in which salicylate anions are located in the interplanar space between the {110}-type planes in the lattice of ADP. The luminescence spectra contain an emission band maximum with λ max=360 nm. In acidic solutions there are ADP:HSal crystals in which salicylic acid molecules captured by the growth macrosteps are located in the interplanar space of the prismatic {100} and pyramidal {101} growth sectors. The luminescence band undergoes bathochromic shift to λmax=400 nm. The sensitivity of ADP:NH 4Sal scintillation crystals to fast neutrons depends on the concentration of ammonium salicylate in ADP matrix. The highest neutron sensitivity is characteristic of the co-doped ADP:NH 4Sal/Tl scintillation crystals.

  9. Ammonium ion binding to DNA G-quadruplexes: do electrospray mass spectra faithfully reflect the solution-phase species?

    PubMed Central

    Balthasart, Françoise; Plavec, Janez; Gabelica, Valérie

    2013-01-01

    G-quadruplex nucleic acids can bind ammonium ions in solution and these complexes can be detected by electrospray mass spectrometry (ESI-MS). However, because ammonium ions are volatile, the extent to which ESI-MS quantitatively could provide an accurate reflection of such solution-phase equilibria is unclear. Here we studied five G-quadruplexes having known solution-phase structure and ammonium ion binding constants: the bimolecular G-quadruplexes (dG4T4G4)2, (dG4T3G4)2 and (dG3T4G4)2, and the intramolecular G-quadruplexes dG4(T4G4)3 and dG2T2G2TGTG2T2G2 (thrombin binding aptamer). We found that not all mass spectrometers are equally suited to reflect the solution phase species. Ion activation can occur in the electrospray source, or in a high-pressure travelling wave ion mobility cell. When the softest instrumental conditions are used, ammonium ions bound between G-quartets, but also additional ammonium ions bound at specific sites outside the external G-quartets can be observed. However, even specifically bound ammonium ions are in some instances too labile to be fully retained in the gas phase structures, and although the ammonium ion distribution observed by ESI-MS shows biases at specific stoichiometries, the relative abundances in solution are not always faithfully reflected. Ion mobility spectrometry results show that all inter-quartet ammonium ions are necessary to preserve the G-quadruplex fold in the gas phase. Ion mobility experiments therefore help assigning the number of inner ammonium ions in the solution phase structure. PMID:23132414

  10. Alanine synthesis from glyceraldehyde and ammonium ion in aqueous solution

    NASA Technical Reports Server (NTRS)

    Weber, A. L.

    1985-01-01

    The formation of alanine (ala) form C(14)-glyceraldehyde and ammonium phosphate in the presence or absence of a thiol is reported. At ambient temperature, ala synthesis was six times more rapid in the presence of 3-mercaptopropionic acid than in its absence (0.6 and 0.1 percent, respectively, after 60 days). Similarly, the presence of another thiol, N-acetylcysteinate, increased the production of ala, as well as of lactate. The reaction pathway of thiol-catalyzed synthesis of ala, with the lactic acid formed in a bypath, is suggested. In this, dehydration of glyceraldehyde is followed by the formation of hemithioacetal. In the presence of ammonia, an imine is formed, which eventually yields ala. This pathway is consistent with the observation that the rate ratio of ala/lactate remains constant throughout the process. The fact that the reaction takes place under anaerobic conditions in the presence of H2O and with the low concentrations of simple substrates and catalysts makes it an attractive model prebiotic reaction in the process of molecular evolution.

  11. EPR and optical absorption studies on Gd 3+ ions in ammonium hydrogen malonate single crystals

    NASA Astrophysics Data System (ADS)

    Kripal, Ram; Mishra, Indrajeet

    2010-01-01

    X-Band electron paramagnetic resonance (EPR) studies of Gd 3+ ions in ammonium hydrogen malonate single crystals have been done at room temperature. Detailed EPR analysis indicates the presence of four physically equivalent but magnetically inequivalent sites. The zero-field splitting parameters and g factor are determined. The Gd 3+ ion is in 8S state; its levels are split by the action of the crystalline electric field of monoclinic symmetry. The optical absorption spectra of Gd 3+ ions in single crystals of ammonium hydrogen malonate are also recorded at room temperature. The energy levels of the 4f 7 configuration are calculated and compared with those observed experimentally. The values of E1=5854±11, E2=31±0.36, E3=592±3.3 and ζ 4f=1595±25 cm -1 are found to give the best over-all agreement between experimentally observed and calculated levels.

  12. Ion exchange of ammonium in natural and synthesized zeolites.

    PubMed

    Wang, Yifei; Lin, Feng; Pang, Wenqin

    2008-12-30

    In this study, zeolite Na-P and Na-Y was prepared by hydrothermal treatment of the Chinese natural clinoptilolite with NaOH. The ion exchange of NH4+ into the three zeolites in the temperature range of 288-333K was also investigated, and the thermodynamic parameters were calculated. The selectivity sequence for NH4+ entering the sodium form of the three materials was Na-clinoptilolite>Na-Y>Na-P, as indicated by values of DeltaG degrees . The results demonstrated that the Si/Al molar ratio of zeolites determined the selectivity for NH4+.

  13. Destruction of organic wastes by ammonium peroxydisulfate with electrolytic regeneration of the oxidant

    SciTech Connect

    Cooper, J.F.; Wang, J.F.; Krueger, R.; King, K.

    1997-07-01

    Research is reported concerning a new aqueous process for oxidative destruction of solid- and liquid organic wastes. This process uses acidified ammonium peroxydisulfate and operates at ambient pressure and at 80- to 100 {degrees}C. The oxidant may be efficiently regenerated by electrolysis of the sulfate by-product at Pt anodes, even in the presence of organic and inorganic contaminants expected to be entrained in the cycle. Integral rate constants were determined for the oxidation of 25 diverse organic compounds at low (50 ppm) concentrations through fixed-time experiments with excess oxidant and a Pt wire catalyst. For high initial concentrations, uncatalyzed mineralization rates were measured for waste surrogates including kerosene, triethylamine, ion exchange resin, oxalic acid, trinitrotoluene, and cellulose. A packed bed reactor was tested with ethylene glycol, with offgas analysis by mass spectroscopy. Rate data extrapolate to throughputs of approximately 200 kg/m{sub 3}-day. The process may benefit the destruction of highly toxic or specialized industrial wastes as well as the organic fraction of mixed wastes.

  14. Hygroscopicity of organic compounds from biomass burning and their influence on the water uptake of mixed organic ammonium sulfate aerosols

    NASA Astrophysics Data System (ADS)

    Lei, T.; Zuend, A.; Wang, W. G.; Zhang, Y. H.; Ge, M. F.

    2014-10-01

    Hygroscopic behavior of organic compounds, including levoglucosan, 4-hydroxybenzoic acid, and humic acid, as well as their effects on the hygroscopic properties of ammonium sulfate (AS) in internally mixed particles are studied by a hygroscopicity tandem differential mobility analyzer (HTDMA). The organic compounds used represent pyrolysis products of wood that are emitted from biomass burning sources. It is found that humic acid aerosol particles only slightly take up water, starting at RH (relative humidity) above ~70%. This is contrasted by the continuous water absorption of levoglucosan aerosol particles in the range 5-90% RH. However, no hygroscopic growth is observed for 4-hydroxybenzoic acid aerosol particles. Predicted water uptake using the ideal solution theory, the AIOMFAC model and the E-AIM (with UNIFAC) model are consistent with measured hygroscopic growth factors of levoglucosan. However, the use of these models without consideration of crystalline organic phases is not appropriate to describe the hygroscopicity of organics that do not exhibit continuous water uptake, such as 4-hydroxybenzoic acid and humic acid. Mixed aerosol particles consisting of ammonium sulfate and levoglucosan, 4-hydroxybenzoic acid, or humic acid with different organic mass fractions, take up a reduced amount of water above 80% RH (above AS deliquescence) relative to pure ammonium sulfate aerosol particles of the same mass. Hygroscopic growth of mixtures of ammonium sulfate and levoglucosan with different organic mass fractions agree well with the predictions of the thermodynamic models. Use of the Zdanovskii-Stokes-Robinson (ZSR) relation and AIOMFAC model lead to good agreement with measured growth factors of mixtures of ammonium sulfate with 4-hydroxybenzoic acid assuming an insoluble organic phase. Deviations of model predictions from the HTDMA measurement are mainly due to the occurrence of a microscopical solid phase restructuring at increased humidity (morphology

  15. Simultaneous uptake of ammonium and phosphate ions by compounds prepared from paper sludge ash.

    PubMed

    Okada, Kiyoshi; Ono, Yosuke; Kameshima, Yoshikazu; Nakajima, Akira; MacKenzie, Kenneth J D

    2007-03-22

    Al-containing CaO-SiO(2)-H(2)O phases were prepared by hydrothermal treatment of mixtures of paper sludge ash (PSA) with various silica and calcia sources and their properties were determined with particular reference to the simultaneous uptake of ammonium and phosphate ions, which are implicated in the eutrophication of lakes and ponds. After examination of various silica and calcia sources, Ca(OH)(2) and SiO(2) sol were selected as the most appropriate starting materials. Dry milling was found to be superior to wet milling in avoiding contamination from the milling media during mixing. Nine samples with three different Ca/Si ratios and Al(2)O(3) contents were prepared with various mass ratios of Ca(OH)(2), PSA and SiO(2). The chemical compositions of the hydrothermal products of these mixtures moved towards the tieline of CaSiO(3)-PSA, with respect to the starting compositions. The major phase formed in all samples was poorly crystalline C-S-H(I), with hydroxysodalite also formed in the Al-containing mixtures. All the products showed a capacity for the simultaneous uptake of ammonium and phosphate ions. The saturated sorption capacities calculated from the Langmuir equation ranged from 0.9 to 2.4mmol/g for the ammonium ion and from 3.3 to 5.2mmol/g for the phosphate ion. Since the sorption capacities for both ions increased with increasing Ca contents of the product, substitution of Ca(2+) for NH(4)(+) and the formation of calcium phosphate phases such as apatite and brushite by precipitation are thought to be the main sorption mechanisms.

  16. The effect of ammonium ions on oxygen reduction and hydrogen peroxide formation on polycrystalline Pt electrodes

    NASA Astrophysics Data System (ADS)

    Halseid, Rune; Heinen, Martin; Jusys, Zenonas; Jürgen Behm, R.

    The influence of ammonium ions on the activity and selectivity of the electrocatalytic oxygen reduction reaction (ORR) on polycrystalline Pt was investigated in model studies under continuous mass transport, both in sulfuric and perchloric acid solutions. Ammonium was found to increase the yield of hydrogen peroxide, particularly in sulfuric acid, but also in perchloric acid solutions, and also at higher potentials (0.80-0.90 V RHE) typical for fuel cell cathode operation, which may severely impair the long-term stability of membranes and electrodes in fuel cells exposed to fuel gases and/or air containing ammonia. Adsorbed species, assigned to ammonia and nitric oxide, were identified on a Pt film electrode using in situ FTIR spectroscopy. Adsorbed nitric oxide could only be observed in perchloric acid solutions. The higher coverage of adsorbed ammonia in sulfuric acid solution is attributed to a stabilization by coadsorbed (bi-)sulfate species; the higher total coverage in this electrolyte can explain the larger effect of ammonium ions on the ORR activity and selectivity in sulfuric compared to perchloric acid solution.

  17. The application of membrane filtration for the removal of ammonium ions from potable water.

    PubMed

    Kurama, H; Poetzschke, J; Haseneder, R

    2002-06-01

    It is well recognized that soluble ammonia and nitrite in drinking water has chronic effects on humans. Ammonia has potential environmental health hazards, particularly to young children. European Union Standards limit the concentration of ammonia to 0.5 mg/l in drinking water. In Eskisehir (Turkey) drinking and tap water are supplied from a water treatment plant, consisting mainly of screening, sedimentation, filtration and sterilization units and having a capacity of 80.000 m3/d. Depend on the industrial and climatic effects the observed high ammonium concentration in treated water causes undesirable effects of water quality. Therefore, people in Eskisehir do not want to use tap water for drinking. The aim of the study was to evaluate the performance of membrane processes, i.e. Nanofiltration and reverse osmosis to the removal of ammonium and Ca ions from plant effluent and recommend one of them for a subsequent pilot plant application.

  18. Chromatographic separation of certain metal ions using a bifunctional quaternary ammonium-sulfonate mixed bed ion-exchanger.

    PubMed

    Lasheen, Y F; Seliman, A F; Abdel-Rassoul, A A

    2006-12-15

    The separation behaviour of Pb(2+), Cu(2+), Cd(2+), Co(2+), Zn(2+) and Ni(2+) on bifunctional quaternary ammonium-sulfonate mixed ion-exchangers (Dionex, IonPac CS5 and CG5) was studied using different eluents including solutions of oxalic acid, potassium oxalate, sodium oxalate and ammonium oxalate. Separated metal ions were followed by using 4-(2-pyridylazo) resorcinol (PAR) as post-colouring complex. The retention factors of different ions proved to be dependent on the pH, concentration, nature of each complexing agent, and to less extent on eluent flow rate. The retention behaviour and separation mechanism of complexed metal analytes are discussed in the light of the stability of metal complexes and the ligand complexing ability of used eluent. Comparison between various mobile phases is evaluated, and both sodium and potassium oxalate can be used successfully for simultaneous separation of studied metals with good resolution within short elution periods. The method can be used in different applications including analysis of bottled water from different resources.

  19. Interface Engineering of Metal Oxides using Ammonium Anthracene in Inverted Organic Solar Cells.

    PubMed

    Jeon, Il; Zeljkovic, Sasa; Kondo, Kei; Yoshizawa, Michito; Matsuo, Yutaka

    2016-11-09

    In this work, by casting water-soluble ammonium anthracene on metal oxides, the organic surface modifier re-engineered the interface of the metal oxide to improve charge transport. The energy level of ammonium anthracene increased the work function of indium tin oxide (ITO), functioning as a hole-blocker (electron-transporter). Solar cells in which ITO was treated by the ammonium anthracene produced an average power conversion efficiency (PCE) of 5.8% without ZnO, the electron-transporting layer. When the ammonium anthracene was applied to ZnO, an average PCE of 8.1% was achieved, which is higher than the average PCE of 7.5% for nontreated ZnO-based devices.

  20. EnFET for urea determination in biological fluids using ammonium ion detection

    NASA Astrophysics Data System (ADS)

    Dawgul, Marek; Trybun, Tomasz; Pijanowska, Dorota G.; Torbicz, Wladyslaw

    2003-09-01

    In this paper a method of urease immobilization on the surface of the Siloprene membrane of the ammonium ion sensitive ChemFET is presented. The usability of the sensor for determination of urea in solutions at pH typical for biological fluids (pH 6 to pH 7.5) has been investigated. Due to the fact that the sensor exhibits high sensitivity to samples of low buffer capacity, the method of preliminary sample treatment, consisting in addition of buffers at adequate buffer capacity was developed. The sensors were tested in dialysate and blood plasma.

  1. Ion transport and structural dynamics in homologous ammonium and phosphonium-based room temperature ionic liquids

    DOE PAGES

    Griffin, Phillip J.; Holt, Adam P.; Tsunashima, Katsuhiko; ...

    2015-02-01

    Charge transport and structural dynamics in a homologous pair of ammonium and phosphonium based room temperature ionic liquids (ILs) have been characterized over a wide temperature range using broadband dielectric spectroscopy and quasi-elastic light scattering spectroscopy. We have found that the ionic conductivity of the phosphonium based IL is significantly enhanced relative to the ammonium homolog, and this increase is primarily a result of a lower glass transition temperature and higher ion mobility. Additionally, these ILs exhibit pronounced secondary relaxations which are strongly influenced by the atomic identity of the cation charge center. While the secondary relaxation in the phosphoniummore » IL has the expected Arrhenius temperature dependence characteristic of local beta relaxations, the corresponding relaxation process in the ammonium IL was found to exhibit a mildly non-Arrhenius temperature dependence in the measured temperature range-indicative of molecular cooperativity. These differences in both local and long-range molecular dynamics are a direct reflection of the subtly different inter-ionic interactions and mesoscale structures found in these homologous ILs.« less

  2. Ion transport and structural dynamics in homologous ammonium and phosphonium-based room temperature ionic liquids

    SciTech Connect

    Griffin, Phillip J.; Holt, Adam P.; Tsunashima, Katsuhiko; Sangoro, Joshua R.; Kremer, Friedrich; Sokolov, Alexei P.

    2015-02-01

    Charge transport and structural dynamics in a homologous pair of ammonium and phosphonium based room temperature ionic liquids (ILs) have been characterized over a wide temperature range using broadband dielectric spectroscopy and quasi-elastic light scattering spectroscopy. We have found that the ionic conductivity of the phosphonium based IL is significantly enhanced relative to the ammonium homolog, and this increase is primarily a result of a lower glass transition temperature and higher ion mobility. Additionally, these ILs exhibit pronounced secondary relaxations which are strongly influenced by the atomic identity of the cation charge center. While the secondary relaxation in the phosphonium IL has the expected Arrhenius temperature dependence characteristic of local beta relaxations, the corresponding relaxation process in the ammonium IL was found to exhibit a mildly non-Arrhenius temperature dependence in the measured temperature range-indicative of molecular cooperativity. These differences in both local and long-range molecular dynamics are a direct reflection of the subtly different inter-ionic interactions and mesoscale structures found in these homologous ILs.

  3. Ion transport and structural dynamics in homologous ammonium and phosphonium-based room temperature ionic liquids

    SciTech Connect

    Griffin, Philip J.; Holt, Adam P.; Tsunashima, Katsuhiko; Sangoro, Joshua R.; Kremer, Friedrich; Sokolov, Alexei P.

    2015-02-28

    Charge transport and structural dynamics in a homologous pair of ammonium and phosphonium based room temperature ionic liquids (ILs) have been characterized over a wide temperature range using broadband dielectric spectroscopy and quasi-elastic light scattering spectroscopy. We have found that the ionic conductivity of the phosphonium based IL is significantly enhanced relative to the ammonium homolog, and this increase is primarily a result of a lower glass transition temperature and higher ion mobility. Additionally, these ILs exhibit pronounced secondary relaxations which are strongly influenced by the atomic identity of the cation charge center. While the secondary relaxation in the phosphonium IL has the expected Arrhenius temperature dependence characteristic of local beta relaxations, the corresponding relaxation process in the ammonium IL was found to exhibit a mildly non-Arrhenius temperature dependence in the measured temperature range—indicative of molecular cooperativity. These differences in both local and long-range molecular dynamics are a direct reflection of the subtly different inter-ionic interactions and mesoscale structures found in these homologous ILs.

  4. 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.

  5. Effects of organic matter content and composition on ammonium adsorption in lake sediments.

    PubMed

    Zhang, Li; Wang, Shengrui; Jiao, Lixin; Li, Yanping; Yang, Jiachun; Zhang, Rui; Feng, Shuang; Wang, Juan

    2016-04-01

    The nature of the influence of organic matter (OM) on ammonium adsorption in lake sediments remains disputed. In this study, the kinetics and thermodynamics of ammonium adsorption were investigated on sediment samples with different OM contents (ignoring the effects of OM mineralization) previously collected from Lake Wuli, a northern bay of Lake Taihu, a shallow lake in southern China. The mechanisms of ammonium adsorption in these samples were characterized by Fourier transform infrared spectrometry and scanning electron microscopy. The results show that the ammonium adsorption capacity of the sediments is highly correlated with their OM content and with the humic content of the OM. The ammonium adsorption capacity of OM varies with its composition, i.e., with the surface properties of the different functional groups present. Indeed, humic acid was found to have a greater ammonium adsorption capacity by itself than when mixed with kerogen and black carbon, the mixture of the latter two components proving a better adsorbent than pure black carbon.

  6. CHLORIDEDETERMINATION IN HIGH IONIC STRENGTH SOLUTION OF AMMONIUM ACETATE USING NEGATIVE ION ELECTRON SPRAY IONIZATION (HPLC/MS)

    EPA Science Inventory

    A precise ion chromatography method has been developed for the determination of chloride in high ionic strength ammonium acetate solutions (10-5 M-5 M) using sodium carbonate/sodium bicarbonate as eluent. Negative ion electrospray ionization (ESI) mass spectrometry was used for q...

  7. Ion chromatography with the indirect ultraviolet detection of alkali metal ions and ammonium using imidazolium ionic liquid as ultraviolet absorption reagent and eluent.

    PubMed

    Liu, Yong-Qiang; Yu, Hong

    2016-08-01

    Indirect ultraviolet detection was conducted in ultraviolet-absorption-agent-added mobile phase to complete the detection of the absence of ultraviolet absorption functional group in analytes. Compared with precolumn derivatization or postcolumn derivatization, this method can be widely used, has the advantages of simple operation and good linear relationship. Chromatographic separation of Li(+) , Na(+) , K(+) , and NH4 (+) was performed on a carboxylic acid base cation exchange column using imidazolium ionic liquid/acid/organic solvent as the mobile phase, in which imidazolium ionic liquids acted as ultraviolet absorption reagent and eluting agent. The retention behaviors of four kinds of cations are discussed, and the mechanism of separation and detection are described. The main factors influencing the separation and detection were the background ultraviolet absorption reagent and the concentration of hydrogen ion in the ion chromatography-indirect ultraviolet detection. The successful separation and detection of Li(+) , Na(+) , K(+) , and NH4 (+) within 13 min was achieved using the selected chromatographic conditions, and the detection limits (S/N = 3) were 0.02, 0.11, 0.30, and 0.06 mg/L, respectively. A new separation and analysis method of alkali metal ions and ammonium by ion chromatography with indirect ultraviolet detection method was developed, and the application range of ionic liquid was expanded.

  8. New Developments in Chiral Cooperative Ion Pairing Organocatalysis by Means of Ammonium Oxyanions and Fluorides: From Protonation to Deprotonation Reactions.

    PubMed

    Legros, Fabien; Oudeyer, Sylvain; Levacher, Vincent

    2016-10-13

    This personal account summarizes our contribution to the ion pairing organocatalysis mainly by use of chiral quaternary or tertiary ammonium fluorides, aryloxides and carboxylates. Starting from an experimental observation, we were able to develop several approaches for the enantioselective protonation of silyl enolates and enol esters giving rise to chiral carbonyl compounds bearing a stereogenic center at the α-position. Moving from protonation to deprotonation reactions, chiral ammonium ion pair catalysts were successfully applied to several asymmetric transformations such as an Henry reaction or a direct vinylogous aldol reaction to cite a few. An outlook of further possible developments in this field of research will also be discussed.

  9. Ammonium first: natural mosses prefer atmospheric ammonium but vary utilization of dissolved organic nitrogen depending on habitat and nitrogen deposition.

    PubMed

    Liu, Xue-Yan; Koba, Keisuke; Makabe, Akiko; Li, Xiao-Dong; Yoh, Muneoki; Liu, Cong-Qiang

    2013-07-01

    Mosses, among all types of terrestrial vegetation, are excellent scavengers of anthropogenic nitrogen (N), but their utilization of dissolved organic N (DON) and their reliance on atmospheric N remain uncharacterized in natural environments, which obscures their roles in N cycles. Natural (15) N abundance of N sources (nitrate (NO(3)(-)), ammonium (NH(4)(+)) and DON in deposition and soil) for epilithic and terricolous mosses was analyzed at sites with different N depositions at Guiyang, China. Moss NO(3)(-) assimilation was inhibited substantially by the high supply of NH(4)(+) and DON. Therefore, contributions of NH(4)(+) and DON to moss N were partitioned using isotopic mass-balance methods. The N contributions averaged 56% and 46% from atmospheric NH(4)(+), and 44% and 17% from atmospheric DON in epilithic and terricolous mosses, respectively. In terricolous mosses, soil NH(4)(+) and soil DON accounted for 16% and 21% of bulk N, which are higher than current estimations obtained using (15) N-labeling methods. Moreover, anthropogenic NH(4)(+) deposition suppressed utilization of DON and soil N because of the preference of moss for NH(4)(+) under elevated NH(4)(+) deposition. These results underscore the dominance of, and preference for, atmospheric NH(4)(+) in moss N utilization, and highlight the importance of considering DON and soil N sources when estimating moss N sequestration and the impacts of N deposition on mosses.

  10. To Break or to Brake Neuronal Network Accelerated by Ammonium Ions?

    PubMed Central

    Dynnik, Vladimir V.; Kononov, Alexey V.; Sergeev, Alexander I.; Teplov, Iliya Y.; Tankanag, Arina V.; Zinchenko, Valery P.

    2015-01-01

    Purpose The aim of present study was to investigate the effects of ammonium ions on in vitro neuronal network activity and to search alternative methods of acute ammonia neurotoxicity prevention. Methods Rat hippocampal neuronal and astrocytes co-cultures in vitro, fluorescent microscopy and perforated patch clamp were used to monitor the changes in intracellular Ca2+- and membrane potential produced by ammonium ions and various modulators in the cells implicated in neural networks. Results Low concentrations of NH4Cl (0.1–4 mM) produce short temporal effects on network activity. Application of 5–8 mM NH4Cl: invariably transforms diverse network firing regimen to identical burst patterns, characterized by substantial neuronal membrane depolarization at plateau phase of potential and high-amplitude Ca2+-oscillations; raises frequency and average for period of oscillations Ca2+-level in all cells implicated in network; results in the appearance of group of «run out» cells with high intracellular Ca2+ and steadily diminished amplitudes of oscillations; increases astrocyte Ca2+-signalling, characterized by the appearance of groups of cells with increased intracellular Ca2+-level and/or chaotic Ca2+-oscillations. Accelerated network activity may be suppressed by the blockade of NMDA or AMPA/kainate-receptors or by overactivation of AMPA/kainite-receptors. Ammonia still activate neuronal firing in the presence of GABA(A) receptors antagonist bicuculline, indicating that «disinhibition phenomenon» is not implicated in the mechanisms of networks acceleration. Network activity may also be slowed down by glycine, agonists of metabotropic inhibitory receptors, betaine, L-carnitine, L-arginine, etc. Conclusions Obtained results demonstrate that ammonium ions accelerate neuronal networks firing, implicating ionotropic glutamate receptors, having preserved the activities of group of inhibitory ionotropic and metabotropic receptors. This may mean, that ammonia

  11. Ion-chromatographic behavior of alkali metal cations and ammonium ion on zirconium-adsorbing silica gel.

    PubMed

    Ohta, K; Morikawa, H; Tanaka, K; Uwamino, Y; Furukawa, M; Sando, M

    2000-07-07

    The preparation and evaluation of zirconium-adsorbing silica gel (Zr-Silica) as an ion-exchange stationary phase in ion chromatography for inorganic anions and cations was carried out. The Zr-Silica was prepared by the reaction of silanol groups on the surface of the silica gel with zirconium butoxide (Zr(OCH2CH2CH2CH3)4) in ethanol. The ion-exchange characteristics of the Zr-Silica were evaluated using 10 mM tartaric acid at pH 2.5 as eluent. The Zr-Silica was found to act as a cation-exchanger under the eluent conditions. The retention behavior of alkali and alkaline earth metal cations was then investigated. The Zr-Silica column was proved to be suitable for the simultaneous separation of alkali metal cations and ammonium ion. Excellent separation of the cations on a 15 cm Zr-Silica column was achieved in 25 min using 10 mM tartaric acid as eluent.

  12. Strategic feeding of ammonium and metal ions for enhanced GLA-rich lipid accumulation in Cunninghamella bainieri 2A1.

    PubMed

    Shuib, Shuwahida; Nawi, Wan Nazatul Naziah Wan; Taha, Ekhlass M; Omar, Othman; Kader, Abdul Jalil Abdul; Kalil, Mohd Sahaid; Hamid, Aidil Abdul

    2014-01-01

    Strategic feeding of ammonium and metal ions (Mg(2+), Mn(2+), Fe(3+), Cu(2+), Ca(2+), Co(2+), and Zn(2+)) for enhanced GLA-rich lipid accumulation in C. bainieri 2A1 was established. When cultivated in nitrogen-limited medium, the fungus produced up to 30% lipid (g/g biomass) with 12.9% (g/g lipid) GLA. However, the accumulation of lipid stopped at 48 hours of cultivation although glucose was abundant. This event occurred in parallel to the diminishing activity of malic enzyme (ME), fatty acid synthase (FAS), and ATP citrate lyase (ACL) as well as the depletion of metal ions in the medium. Reinstatement of the enzymes activities was achieved by feeding of ammonium tartrate, but no increment in the lipid content was observed. However, increment in lipid content from 32% to 50% (g/g biomass) with 13.2% GLA was achieved when simultaneous feeding of ammonium, glucose, and metal ions was carried out. This showed that the cessation of lipid accumulation was caused by diminishing activities of the enzymes as well as depletion of the metal ions in the medium. Therefore, strategic feeding of ammonium and metal ions successfully reinstated enzymes activities and enhanced GLA-rich lipid accumulation in C. bainieri 2A1.

  13. Strategic Feeding of Ammonium and Metal Ions for Enhanced GLA-Rich Lipid Accumulation in Cunninghamella bainieri 2A1

    PubMed Central

    Wan Nawi, Wan Nazatul Naziah; Taha, Ekhlass M.; Omar, Othman; Abdul Kader, Abdul Jalil; Kalil, Mohd Sahaid; Abdul Hamid, Aidil

    2014-01-01

    Strategic feeding of ammonium and metal ions (Mg2+, Mn2+, Fe3+, Cu2+, Ca2+, Co2+, and Zn2+) for enhanced GLA-rich lipid accumulation in C. bainieri 2A1 was established. When cultivated in nitrogen-limited medium, the fungus produced up to 30% lipid (g/g biomass) with 12.9% (g/g lipid) GLA. However, the accumulation of lipid stopped at 48 hours of cultivation although glucose was abundant. This event occurred in parallel to the diminishing activity of malic enzyme (ME), fatty acid synthase (FAS), and ATP citrate lyase (ACL) as well as the depletion of metal ions in the medium. Reinstatement of the enzymes activities was achieved by feeding of ammonium tartrate, but no increment in the lipid content was observed. However, increment in lipid content from 32% to 50% (g/g biomass) with 13.2% GLA was achieved when simultaneous feeding of ammonium, glucose, and metal ions was carried out. This showed that the cessation of lipid accumulation was caused by diminishing activities of the enzymes as well as depletion of the metal ions in the medium. Therefore, strategic feeding of ammonium and metal ions successfully reinstated enzymes activities and enhanced GLA-rich lipid accumulation in C. bainieri 2A1. PMID:24991637

  14. Physicochemical properties and ion-solvent interactions in aqueous sodium, ammonium, and lead acetate solution

    NASA Astrophysics Data System (ADS)

    Deosarkar, S. D.; Mendkudle, M. S.

    2014-09-01

    Densities (ρ), viscosities (η) and refractive indices ( n D) of aqueous sodium acetate (SA), ammonium acetate (AA), and lead acetate (LA) solutions have been measured for different concentrations of salts at 302.15 K. Apparent molar volumes (φv) for studied solutions were calculated from density data, and fitted to Masson's relation and partial molar volume (φ{v/o}) was determined. Viscosity data were fitted to Jones-Dole equation and viscosity A- and B-coefficients were determined. Refractive index and density data were fitted to Lorentz and Lorenz equation and specific refraction ( R D) were calculated. Behavior of various physicochemical properties indicated presence of strong ion-solvent interactions in present systems and the acetate salts structure maker in water.

  15. Induced binding of proteins by ammonium sulfate in affinity and ion-exchange column chromatography.

    PubMed

    Arakawa, Tsutomu; Tsumoto, Kouhei; Ejima, Daisuke; Kita, Yoshiko; Yonezawa, Yasushi; Tokunaga, Masao

    2007-04-10

    In general, proteins bind to affinity or ion-exchange columns at low salt concentrations, and the bound proteins are eluted by raising the salt concentration, changing the solvent pH, or adding competing ligands. Blue-Sepharose is often used to remove bovine serum albumin (BSA) from samples, but when we applied BSA to Blue-Sepharose in 20 mM phosphate, pH 7.0, 50%-60% of the protein flowed through the column; however, complete binding of BSA was achieved by the addition of 2 M ammonium sulfate (AS) to the column equilibration buffer and the sample. The bound protein was eluted by decreasing the AS concentration or by adding 1 M NaCl or arginine. AS at high concentrations resulted in binding of BSA even to an ion-exchange column, Q-Sepharose, at pH 7.0. Thus, although moderate salt concentrations elute proteins from Blue-Sepharose or ion-exchange columns, proteins can be bound to these columns under extreme salting-out conditions. Similar enhanced binding of proteins by AS was observed with an ATP-affinity column.

  16. Regulation of renin release by calcium and ammonium ions in normal man.

    PubMed

    Kisch, E S; Dluhy, R G; Williams, G H

    1976-12-01

    The effect of infusing calcium chloride, magnesium sulfate, sodium lactate, and ammonium chloride on renin secretion was compared to equimolar infusions of hypotonic and normal saline in sodium-deplete normal subjects. The infusion of 75 mEq of ammonium chloride for 60 min in 6 normal, sodium-deplete subjects suppressed plasma renin activity significantly (P less than 0.01) from 4.4 +/- 0.8 to 2.1 +/- 0.2 ng/ml/h, an effect comparable to that produced by normal saline. Sodium lactate (75 mEq sodium/hr) also significantly reduced renin levels at 20-30 min (P less than 0.01). The infusion of 1/3 normal saline (25 mEq sodium/h for 2 h) produced a significant reduction (P less than 0.01) in plasma renin activity (from control levels of 5.2 +/- 0.8 to 3.1 +/- 0.6 ng/ml/h at 90 min). On the other hand, comparable infusions of 50 mEq of magnesium sulfate over 2 h had no effect on renin release (4.6 +/- 0.8 to 4.6 +/- 0.9 ng/ml/h at 2 h), while the infusion of calcium chloride produced an intermediate reduction (5.2 +/- 1.2 to 3.7 +/- 0.8 ng/ml/h at 2 h (P less than 0.05). The observed effects of the hydrogen and calcium ions on suppressing renin release may be secondary to their known actions on renal sodium excretion. Since the infusions of calcium and hydrogen ions both result in an increased delivery of sodium to the distal segment of the nephron, the results may reflect the regulation of renin by the macula densa, a sensitive intrarenal sensor of renal tubular sodium.

  17. Chemical ions affect survival of avian cholera organisms in pondwater

    USGS Publications Warehouse

    Price, J.I.; Yandell, B.S.; Porter, W.P.

    1992-01-01

    Avian cholera (Pasteurella multocida) is a major disease of wild waterfowl, but its epizootiology remains little understood. Consequently, we examined whether chemical ions affected survival of avian cholera organisms in water collected from the Nebraska Rainwater Basin where avian cholera is enzootic. We tested the response of P. multocida to ammonium (NH4), calcium (Ca), magnesium (Mg), nitrate (NO3), and ortho-phosphate (PO4) ions individually and in combination using a fractional factorial design divided into 4 blocks. High concentrations of Ca and Mg, singly or in combination, increased survival of P. multocida organisms (P < 0.001). We developed a survival index to predict whether or not specific ponds could be "problem" or "nonproblem" avian cholera sites based on concentrations of these ions in the water.

  18. The selectivity of different external binding sites for quaternary ammonium ions in cloned potassium channels.

    PubMed

    Jarolimek, W; Soman, K V; Brown, A M; Alam, M

    1995-09-01

    Tetraethylammonium (TEA) is thought to be the most effective quaternary ammonium (QA) ion blocker at the external site of K+ channels, and small changes to the TEA ion reduce its potency. To examine the properties of the external QA receptor, we applied a variety of QA ions to excised patches from human embryonic kidney cells or Xenopus oocytes transfected with the delayed rectifying K+ channels Kv 2.1 and Kv 3.1. In outside-out patches of Kv 3.1, the relative potencies were TEA > tetrapropylammonium (TPA) > tetrabutylammonium (TBA). In contrast to Kv 3.1, the relative potencies in Kv 2.1 were TBA > TEA > TPA. In Kv 3.1 and Kv 2.1, external tetrapentylammonium (TPeA) blocked K+ currents in a fast, reversible and, in contrast to TEA, time-dependent manner. The external binding of TPeA appeared to be voltage independent, unlike the effects of TPeA applied to inside-out patches. External n-alkyl-triethylammonium compounds (C8, C10 chain length) had a lower affinity than TEA in Kv 3.1, but a higher affinity than TEA in Kv 2.1. In Kv 3.1, the decrease in QA affinity was large when one or two methyl groups were substituted for ethyl groups in TEA, but minor when propyl groups replaced ethyl groups. Changes in the free energy of binding could be correlated to changes in the free energy of hydration of TEA derivatives calculated by continuum methodology. These results reveal a substantial hydrophobic component of external QA ion binding to Kv 2.1, and to a lesser degree to Kv 3.1, in addition to the generally accepted electrostatic interactions. The chain length of hydrophobic TEA derivatives affects the affinity for the hydrophobic binding site, whereas the hydropathy of QA ions determines the electrostatic interaction energy.

  19. Ion produced cometary organic crust

    NASA Technical Reports Server (NTRS)

    Baratta, G. Antonio; Strazzulla, G.

    1992-01-01

    For several years many experimental results have been obtained on the chemical and physical changes induced by ion and electron irradiation of materials with a view to their Astrophysical relevance. Among the studied effects, one of particular interest is the formation of an organic refractory residue left over after ion irradiation and warming-up at room temperature. We call this residue IPHAC (ion produced hydrogenated amorphous carbon). Although 'in situ' infrared spectroscopy points out the formation of new molecular species during bombardment at low temperature, it is not clear if IPHAC is already formed or if its formation is triggered by temperature increase during warming-up of the irradiated target. Since Raman Spectroscopy is a technique particularly suitable for the analysis of carbonaceous materials, we have thought and build-up an experimental apparatus to obtain Raman Spectra of frozen hydrocarbons during ion irradiation. The present experimental results point out clearly to the formation of IPHAC already at low T and low energy deposition (approximately equal to a few eV/C-atom).

  20. UREA/ammonium ion removal system for the orbiting frog otolith experiment. [ion exchange resins for water treatment during space missions

    NASA Technical Reports Server (NTRS)

    Schulz, J. R.; Anselmi, R. T.

    1976-01-01

    The feasibility of using free urease enzyme and ANGC-101 ion exchange resin to remove urea and ammonium ion for space system waste water applications was studied. Specifically examined is the prevention of urea and ammonia toxicity in a 30-day Orbiting Frog Otolith (OFO) flight experiment. It is shown that free urease enzyme used in conjunction with ANGC-101 ion-exchange resin and pH control can control urea and amonium ion concentration in unbuffered recirculating water. In addition, the resin does not adversely effect the bullfrogs by lowering the concentration of cations below critical minimum levels. Further investigations on bioburden control, frog waste excretion on an OFO diet, a trade-off analysis of methods of automating the urea/ammonium ion removal system and fabrication and test of a semiautomated breadboard were recommended as continuing efforts. Photographs of test equipment and test animals are shown.

  1. Synergetic stress of acids and ammonium on the shift in the methanogenic pathways during thermophilic anaerobic digestion of organics.

    PubMed

    Lü, Fan; Hao, Liping; Guan, Dongxing; Qi, Yujiao; Shao, Liming; He, Pinjing

    2013-05-01

    Combined effects of acids and ammonium on functional pathway and microbial structure during organics methanization were investigated by stable isotopic method and quantitative PCR. The results showed that the stress from acids and ammonium was synergetic, resulted in different inhibition for acetoclastic and hydrogenotrophic methanogenesis and syntrophic acetate oxidation, leading to pathway shift. Methane production from acetate was affected more by acetate than by ammonium until the ammonium concentration reached 6-7 g-N/L. When the ammonium concentration exceeded 6 g-N/L, ammonium inhibition was strengthened by the increased concentration of acetate. At a low acetate concentration (50 mmol/L), acetoclastic methanogenesis dominated, regardless of ammonium concentration. At higher acetate concentrations (150 and 250 mmol/L) and at low-medium ammonium levels (1-4 g-N/L), acetate was mainly degraded by acetoclastic methanogenesis, while residual acetate was degraded by a combination of acetoclastic methanogenesis and the syntrophic reaction of syntrophic acetate oxidization and hydrogenotrophic methanogenesis with the latter dominating at 250 mmol/L acetate. At high ammonium levels (6-7 g-N/L), the degradation of acetate in the 150 mmol/L treatment was firstly through a combination of acetoclastic methanogenesis and the syntrophic pathway and then gradually shifted to the syntrophic pathway, while the degradation of acetate in the 250 mmol/L treatment was completely by the syntrophic pathway.

  2. Combination of ion exchange and partial nitritation/Anammox process for ammonium removal from mainstream municipal wastewater.

    PubMed

    Malovanyy, Andriy; Plaza, Elzbieta; Trela, Jozef; Malovanyy, Myroslav

    2014-01-01

    In this study, a new technology of nitrogen removal from mainstream municipal wastewater is proposed. It is based on ammonium removal by ion exchange and regeneration of ion exchange material with 10-30 g/L NaCl solution with further nitrogen removal from spent regenerant by partial nitritation/Anammox process. Influence of regenerant strength on performance of ion exchange and biological parts of the proposed technology was evaluated. Moreover, the technology was tested in batch mode using pretreated municipal wastewater, strong acid cation (SAC) resin and partial nitritation/Anammox biomass. It was shown that with ion exchange it is possible to remove 99.9% of ammonium from wastewater while increasing the concentration of ammonium in spent regenerant by 18 times. Up to 95% of nitrogen from spent regenerant, produced by regeneration of SAC resin with 10 g/L NaCl solution, was removed biologically by partial nitritation/Anammox biomass. Moreover, the possibilities of integration of the technology into municipal wastewater treatment technology, and the challenges and advantages are discussed.

  3. Optical Constants of the Ammonium Ion: A Potential Ice Product in the Outer Solar System

    NASA Astrophysics Data System (ADS)

    Roush, T. L.; Moore, M. H.; Cook, J. C.

    2008-12-01

    Optical constants, the real and imaginary indices of refraction, are the fundamental values used in a wide variety of radiative transfer models that are relevant to many environments including circumstellar disks, planetary atmospheres, and planetary surfaces. Cook et al. (2007) observed a feature near 2.2 micrometers (um) in the reflectance spectrum of Pluto's moon, Charon. They suggested evidence for both ammonia di- hydrate and ammonia hemi-hydrate on opposite hemispheres of Charon. Moore et al. (2003) discuss the irradiation of N2-CH4-CO ices; mixtures relevant for Pluto, Triton, and a plausible constituent for some Kuiper Belt Objects and Centaurs. One stable product observed after irradiation of the ice mixture is the ammonium ion, NH4+. NH4+ has strong spectral features in the 3-4 um region and weaker overtones near 2.21 and 2.24 um (Moore et al. 2003). The 2.21 um feature is the strongest of the overtone bands and is near the wavelengths observed for Charon. Using the measurements of Moore et al. (2003) the optical constants of NH4+ are estimated and will be available to investigate NH4+ as an alternative candidate for the feature observed on Charon. Moore, M. et al. 2003, Earth Moon Planets, 92, 291-306. Cook, J. et al. 2007, Ap J, 663, 1406-1419.

  4. An operationally flexible fuel cell based on quaternary ammonium-biphosphate ion pairs

    SciTech Connect

    Lee, Kwan -Soo; Spendelow, Jacob Schatz; Choe, Yoong -Kee; Fujimoto, Cy; Kim, Yu Seung

    2016-08-22

    Here, fuel cells are promising devices for clean power generation in a variety of economically and environmentally significant applications. Low-temperature proton exchange membrane (PEM) fuel cells utilizing Nafion require a high level of hydration, which limits the operating temperature to less than 100°C. In contrast, high-temperature PEM fuel cells utilizing phosphoric acid-doped polybenzimidazole can operate effectively up to 180°C; however, these devices degrade when exposed to water below 140°C. Here we present a different class of PEM fuel cells based on quaternary ammonium-biphosphate ion pairs that can operate under conditions unattainable with existing fuel cell technologies. These fuel cells exhibit stable performance at 80–160°C with a conductivity decay rate more than three orders of magnitude lower than that of a commercial high-temperature PEM fuel cell. By increasing the operational flexibility, this class of fuel cell can simplify the requirements for heat and water management, and potentially reduce the costs associated with the existing fully functional fuel cell systems.

  5. An operationally flexible fuel cell based on quaternary ammonium-biphosphate ion pairs

    NASA Astrophysics Data System (ADS)

    Lee, Kwan-Soo; Spendelow, Jacob S.; Choe, Yoong-Kee; Fujimoto, Cy; Kim, Yu Seung

    2016-09-01

    Fuel cells are promising devices for clean power generation in a variety of economically and environmentally significant applications. Low-temperature proton exchange membrane (PEM) fuel cells utilizing Nafion require a high level of hydration, which limits the operating temperature to less than 100 ∘C. In contrast, high-temperature PEM fuel cells utilizing phosphoric acid-doped polybenzimidazole can operate effectively up to 180 ∘C however, these devices degrade when exposed to water below 140 ∘C. Here we present a different class of PEM fuel cells based on quaternary ammonium-biphosphate ion pairs that can operate under conditions unattainable with existing fuel cell technologies. These fuel cells exhibit stable performance at 80-160 ∘C with a conductivity decay rate more than three orders of magnitude lower than that of a commercial high-temperature PEM fuel cell. By increasing the operational flexibility, this class of fuel cell can simplify the requirements for heat and water management, and potentially reduce the costs associated with the existing fully functional fuel cell systems.

  6. An operationally flexible fuel cell based on quaternary ammonium-biphosphate ion pairs

    DOE PAGES

    Lee, Kwan -Soo; Spendelow, Jacob Schatz; Choe, Yoong -Kee; ...

    2016-08-22

    Here, fuel cells are promising devices for clean power generation in a variety of economically and environmentally significant applications. Low-temperature proton exchange membrane (PEM) fuel cells utilizing Nafion require a high level of hydration, which limits the operating temperature to less than 100°C. In contrast, high-temperature PEM fuel cells utilizing phosphoric acid-doped polybenzimidazole can operate effectively up to 180°C; however, these devices degrade when exposed to water below 140°C. Here we present a different class of PEM fuel cells based on quaternary ammonium-biphosphate ion pairs that can operate under conditions unattainable with existing fuel cell technologies. These fuel cells exhibitmore » stable performance at 80–160°C with a conductivity decay rate more than three orders of magnitude lower than that of a commercial high-temperature PEM fuel cell. By increasing the operational flexibility, this class of fuel cell can simplify the requirements for heat and water management, and potentially reduce the costs associated with the existing fully functional fuel cell systems.« less

  7. Novel hierarchical three-dimensional ammonium vanadate nanowires electrodes for lithium ion battery

    NASA Astrophysics Data System (ADS)

    Fang, Dong; Cao, Yunhe; Liu, Ruina; Xu, Weilin; Liu, Suqin; Luo, Zhiping; Liang, Chaowei; Liu, Xiaoqing; Xiong, Chuanxi

    2016-01-01

    Ammonium vanadate (NH4V4O10) nanowire flowers and nanowires on titanium (Ti) foils are synthesized by hexamethylenetetramine (HMTA)-assisted hydrothermal reactions as a cathode material for lithium-ion battery. The as-prepared NH4V4O10 nanowires are about 50 nm in diameter and several micrometers in length. The effects of reaction time, temperature and additive concentration on the resulting morphology are investigated. Reversible lithium intercalation behavior of the nanowires has been evaluated by cyclic voltammetry and galvanostatic discharge⿿charge cycling. The NH4V4O10 nanowires on Ti foil deliver a high discharge capacity of 168.5 mA h g⿿1 after 100 cycles between 2.0 and 4.0 V at 50 mA g⿿1. A high rate capability is obtained with a remaining discharge capacity of about 182.6 mA h g⿿1 after 35 cycles at various rates. Further, the NH4V4O10 nanowires on Ti foil have a higher discharge capacity of 330.5 mA h g⿿1 after 100 cycles at 0.8⿿4.0 V at 50 mA g⿿1.

  8. Characteristics of DO, organic matter, and ammonium profile for practical scale DHS reactor under various organic load and temperature conditions.

    PubMed

    Nomoto, Naoki; Ali, Muntjeer; Jayaswal, Komal; Iguchi, Akinori; Hatamoto, Masashi; Okubo, Tsutomu; Takahashi, Masanobu; Kubota, Kengo; Tagawa, Tadashi; Uemura, Shigeki; Yamaguchi, Takashi; Harada, Hideki

    2017-04-07

    Profile analysis of the down-flow hanging sponge (DHS) reactor was conducted under various temperature and organic load conditions to understand the organic removal and nitrification process for sewage treatment . Under high organic load conditions (3.21~7.89 kg-COD m(-3) day(-1)), dissolved oxygen (DO) on the upper layer of the reactor was affected by organic matter concentration and water temperature and some time become around zero. Almost half of the CODCr was removed by the first layer, which could be attributed to the adsorption of organic matter on sponge media. After the first layer, organic removal proceeded along the first-order reaction equation from the second to the fourth layers. The ammonium nitrogen removal ratio decreased under high organic matter concentration (above 100 mg L(-1)) and low DO (less than 1 mg L(-1)) condition. Ammonium nitrogen removal proceeded via a zero-order reaction equation along the reactor height. In addition, profile results of DO, CODCr, and NH3-N were different in horizontal direction. Thus, it is thought the concentration of these item and microbial activities were not a uniform state even in the same sponge layer of the DHS reactor.

  9. Behavior of an aerated submerged fixed-film reactor (ASFFR) under simultaneous organic and ammonium loading.

    PubMed

    Nabizadeh, R; Mesdaghinia, A

    2006-01-01

    The performance of an aerated submerged fixed-film reactor (ASFFR) under simultaneous organic and ammonium loading and its effect on nitrification was studied. Organic loadings varied in the range of 1.93 to 5.29 g chemical oxygen demand (COD) m-2 d-1 and NH4-N loadings were in the range of 116 to 318 mg NH4-N m-2 d-1. Increments of loading rates were obtained both by increasing the flow rate and increasing the influent substrate in individual pilot runs. Results showed that with organic loading rates up to 3.97 g COD m-2 d-1, complete nitrification was achievable. Although high organic loading such as 5.29 g COD m-2 d-1 could cause nitrification to stop, shifting to lower organic loadings made nitrification start and set rapidly to its previous steady-state concentrations. Comparison of results showed that in the ASFFR, nitrification would be severely affected by an organic loading rate of 5.29 g COD m-2 d-1 by increasing either the flow or the influent substrate. It should be noted that the average value of dissolved oxygen was 3.4 mg L-1 with an air supply of 15 L min-1, and there was no indication of oxygen limitation. The results of this study show the flexibility of ASFFRs under changing organic loads. Furthermore, for achieving complete nitrification and optimum application of these reactors for protecting receiving water from the environmental hazards of ammonium, the maximum organic loading that would present complete nitrification should be considered.

  10. Extrapolating Single Organic Ion Solvation Thermochemistry from Simulated Water Nanodroplets.

    PubMed

    Coles, Jonathan P; Houriez, Céline; Meot-Ner Mautner, Michael; Masella, Michel

    2016-09-08

    We compute the ion/water interaction energies of methylated ammonium cations and alkylated carboxylate anions solvated in large nanodroplets of 10 000 water molecules using 10 ns molecular dynamics simulations and an all-atom polarizable force-field approach. Together with our earlier results concerning the solvation of these organic ions in nanodroplets whose molecular sizes range from 50 to 1000, these new data allow us to discuss the reliability of extrapolating absolute single-ion bulk solvation energies from small ion/water droplets using common power-law functions of cluster size. We show that reliable estimates of these energies can be extrapolated from a small data set comprising the results of three droplets whose sizes are between 100 and 1000 using a basic power-law function of droplet size. This agrees with an earlier conclusion drawn from a model built within the mean spherical framework and paves the road toward a theoretical protocol to systematically compute the solvation energies of complex organic ions.

  11. The Soret absorption band of isolated chlorophyll a and b tagged with quaternary ammonium ions.

    PubMed

    Stockett, Mark H; Musbat, Lihi; Kjær, Christina; Houmøller, Jørgen; Toker, Yoni; Rubio, Angel; Milne, Bruce F; Brøndsted Nielsen, Steen

    2015-10-21

    We have performed gas-phase absorption spectroscopy in the Soret-band region of chlorophyll (Chl) a and b tagged by quaternary ammonium ions together with time-dependent density functional theory (TD-DFT) calculations. This band is the strongest in the visible region of metalloporphyrins and an important reporter on the microenvironment. The cationic charge tags were tetramethylammonium, tetrabutylammonium, and acetylcholine, and the dominant dissociation channel in all cases was breakage of the complex to give neutral Chl and the charge tag as determined by photoinduced dissociation mass spectroscopy. Two photons were required to induce fragmentation on the time scale of the experiment (microseconds). Action spectra were recorded where the yield of the tag as a function of excitation wavelength was sampled. These spectra are taken to represent the corresponding absorption spectra. In the case of Chl a we find that the tag hardly influences the band maximum which for all three tags is at 403 ± 5 nm. A smaller band with maximum at 365 ± 10 nm was also measured for all three complexes. The spectral quality is worse in the case of Chl b due to lower ion beam currents; however, there is clear evidence for the absorption being to the red of that of Chl a (most intense peak at 409 ± 5 nm) and also a more split band. Our results demonstrate that the change in the Soret-band spectrum when one peripheral substituent (CH3) is replaced by another (CHO) is an intrinsic effect. First principles TD-DFT calculations agree with our experiments, supporting the intrinsic nature of the difference between Chl a and b and also displaying minimal spectral changes when different charge tags are employed. The deviations between theory and experiment have allowed us to estimate that the Soret-band absorption maxima in vacuo for the neutral Chl a and Chl b should occur at 405 nm and 413 nm, respectively. Importantly, the Soret bands of the isolated species are significantly blueshifted

  12. Hygroscopic and phase separation properties of ammonium sulfate/organic/water ternary solutions

    NASA Astrophysics Data System (ADS)

    Zawadowicz, M. A.; Proud, S. R.; Seppalainen, S. S.; Cziczo, D. J.

    2015-03-01

    Atmospheric aerosol particles are often partially or completely composed of inorganic salts, such as ammonium sulfate and sodium chloride, and therefore exhibit hygroscopic properties. Many inorganic salts have well-defined deliquescence and efflorescence points at which they take up and lose water, respectively. Deliquescence and efflorescence of simple inorganic salt particles have been investigated by a variety of methods, such as IR spectroscopy, tandem mobility analysis and electrodynamic balance. Field measurements have shown that atmospheric aerosols are not typically pure inorganic salt, instead they often also contain organic species. There is ample evidence from laboratory studies that suggests that mixed particles exist in a phase-separated state, with an aqueous inorganic core and organic shell. Although phase separation has not been measured in situ, there is no reason it would not also take place in the atmosphere. Many recent studies have focused on microscopy techniques that require deposition of the aerosol on a glass slide, possibly changing its surface properties. Here, we investigate the deliquescence and efflorescence points, phase separation and ability to exchange gas-phase components of mixed organic and inorganic aerosol using a flow tube coupled with FTIR spectroscopy. Ammonium sulfate aerosol mixed with organic polyols with different O : C ratios, including 1,4-butanediol, glycerol, 1,2,6-hexanetriol, 1,2-hexanediol, and 1,5-pentanediol have been investigated. Those constituents correspond to materials found in the atmosphere in great abundance, and therefore, particles prepared in this study should mimic atmospheric mixed phase aerosol particles. The results of this study tend to be in agreement with previous microscopy experiments, with several key differences, which possibly reveal a size-dependent effect on phase separation in organic/inorganic aerosol particles.

  13. Hygroscopicity of organic compounds from biomass burning and their influence on the water uptake of mixed organic-ammonium sulfate aerosols

    NASA Astrophysics Data System (ADS)

    Lei, T.; Zuend, A.; Wang, W. G.; Zhang, Y. H.; Ge, M. F.

    2014-05-01

    Hygroscopic behavior of organic compounds, including levoglucosan, 4-hydroxybenzoic acid and humic acid, and their effects on the hygroscopic properties of ammonium sulfate (AS) in internally mixed particles are studied by a hygroscopicity tandem differential mobility analyzer (HTDMA). The organic compounds used represent pyrolysis products of wood that are emitted from biomass burning sources. It is found that humic acid aerosol particles only slightly take up water, starting at RH above ∼70%. This is contrasted by the continuous water absorption of levoglucosan aerosol particles in the range 5-90% RH. However, no hygroscopic growth is observed for 4-hydroxybenzoic acid aerosol particles. Predicted water uptake using the ideal solution theory, the AIOMFAC model and the E-AIM (with UNIFAC) model are consistent with measured hygroscopic growth factors of levoglucosan. However, the use of these models without consideration of crystalline organic phases is not appropriate to describe the hygroscopicity of organics that do not exhibit continuous water uptake, such as 4-hydroxybenzoic acid and humic acid. Mixed aerosol particles consisting of ammonium sulfate and levoglucosan, 4-hydroxybenzoic acid, or humic acid with different organic mass fractions, take up a reduced amount of water above 80% RH (above AS deliquescence) relative to pure ammonium sulfate aerosol particles of the same mass. Hygroscopic growth of mixtures of ammonium sulfate and levoglucosan with different organic mass fractions agree well with the predictions of the thermodynamic models. Use of the Zdanovskii-Stokes-Robinson (ZSR) relation and AIOMFAC model lead to good agreement with measured growth factors of mixtures of ammonium sulfate with 4-hydrobenxybenzoic acid assuming an insoluble organic phase. Deviations of model predictions from the HTDMA measurement are mainly due to the occurrence of a microscopical solid phase restructuring at increased humidity (morphology effects), which are not

  14. Plant diversity effects on leaching of nitrate, ammonium, and dissolved organic nitrogen from an experimental grassland

    NASA Astrophysics Data System (ADS)

    Leimer, Sophia; Oelmann, Yvonne; Wirth, Christian; Wilcke, Wolfgang

    2014-05-01

    Leaching of nitrogen (N) from soil represents a resource loss and, in particular leaching of nitrate, can threaten drinking water quality. As plant diversity leads to a more exhaustive resource use, we investigated the effects of plant species richness, functional group richness, and the presence of specific functional groups on nitrate, ammonium, dissolved organic N (DON), and total dissolved N (TDN) leaching from an experimental grassland in the first 4 years after conversion from fertilized arable land to unfertilized grassland. The experiment is located in Jena, Germany, and consists of 82 plots with 1, 2, 4, 8, 16, or 60 plant species and 1-4 functional groups (legumes, grasses, non-leguminous tall herbs, non-leguminous small herbs). Nitrate, ammonium, and TDN concentrations in soil solution in the 0-0.3 m soil layer were measured every second week during 4 years on 62 plots and DON concentrations were calculated as difference between TDN and inorganic N. Missing concentrations in soil solution were estimated using a Bayesian statistical model. Downward water fluxes (DF) per plot from the 0-0.3 m soil layer were simulated in weekly resolution with a water balance model in connection with a Bayesian model for simulating missing soil water content measurements. To obtain annual nitrate, ammonium, and DON leaching from the 0-0.3 m soil layer per plot, we multiplied the respective concentrations in soil solution with DF and aggregated the data to annual sums. TDN leaching resulted from summation of nitrate, ammonium, and DON leaching. DON leaching contributed most to TDN leaching, particularly in plots without legumes. Dissolved inorganic N leaching in this grassland was dominated by nitrate. The amount of annual ammonium leaching was small and little influenced by plant diversity. Species richness affected DON leaching only in the fourth and last investigated year, possibly because of a delayed soil biota effect that increased microbial transformation of organic

  15. Hygroscopic and phase separation properties of ammonium sulfate/organics/water ternary solutions

    NASA Astrophysics Data System (ADS)

    Zawadowicz, M. A.; Proud, S. R.; Seppalainen, S. S.; Cziczo, D. J.

    2015-08-01

    Atmospheric aerosol particles are often partially or completely composed of inorganic salts, such as ammonium sulfate and sodium chloride, and therefore exhibit hygroscopic properties. Many inorganic salts have well-defined deliquescence and efflorescence points at which they take up and lose water, respectively. Field measurements have shown that atmospheric aerosols are not typically pure inorganic salt, instead, they often also contain organic species. There is ample evidence from laboratory studies that suggests that mixed particles exist in a phase-separated state, with an aqueous inorganic core and organic shell. Although phase separation has not been measured in situ, there is no reason it would not also take place in the atmosphere. Here, we investigate the deliquescence and efflorescence points, phase separation and ability to exchange gas-phase components of mixed organic and inorganic aerosol using a flow tube coupled with FTIR (Fourier transform infrared) spectroscopy. Ammonium sulfate aerosol mixed with organic polyols with different O : C ratios, including 1,4-butanediol, glycerol, 1,2,6-hexanetriol, 1,2-hexanediol, and 1,5-pentanediol have been investigated. Those constituents correspond to materials found in the atmosphere in great abundance and, therefore, particles prepared in this study should mimic atmospheric mixed-phase aerosol particles. Some results of this study tend to be in agreement with previous microscopy experiments, but others, such as phase separation properties of 1,2,6-hexanetriol, do not agree with previous work. Because the particles studied in this experiment are of a smaller size than those used in microscopy studies, the discrepancies found could be a size-related effect.

  16. Calcium- and ammonium ion-modification of zeolite amendments affects the metal-uptake of Hieracium piloselloides in a dose-dependent way.

    PubMed

    Peter, Anca; Mihaly-Cozmuta, Leonard; Mihaly-Cozmuta, Anca; Nicula, Camelia; Indrea, Emil; Tutu, Hlanganani

    2012-10-26

    The role of natural zeolite and of two types of modified zeolite (with ammonium and with calcium ions) in reducing the accumulation of ions of heavy metals in roots and leaves of Hieracium piloselloides grown on tailing ponds was investigated. The variation of the content of zeolite (5% w/w and 10% w/w) is another parameter that significantly and positively affects the accumulation of the metal ions in Hieracium piloselloides. The results showed that zeolite used as an amendment in the soil in tailing ponds significantly reduces the accumulation of heavy metal ions in Hieracium piloselloides. The highest concentrations of heavy metals were accumulated in plants grown on soil without zeolite, being followed by the plants grown on the substrate with natural zeolite. Moreover, the translocation factors of heavy metal ions uptake in roots and leaves grown on substrates with modified zeolites are lower than those calculated for the organs grown on the substrate amended with natural zeolite. This behaviour has demonstrated the positive effect of those changes of zeolite amendments in the potential phytoremediation practice.

  17. Preparation of immunoglobulin Y from egg yolk using ammonium sulfate precipitation and ion exchange chromatography.

    PubMed

    Ko, K Y; Ahn, D U

    2007-02-01

    The objective of this study was to develop an economical, simple, and large-scale separation method for IgY from egg yolk. Egg yolk diluted with 9 volumes of cold water was centrifuged after adjusting the pH to 5.0. The supernatant was added with 0.01% charcoal or 0.01% carrageenan and centrifuged at 2,800 x g for 30 min. The supernatant was filtered through a Whatman no. 1 filter paper and then the filtrate was concentrated to 20% original volume using ultrafiltration. The concentrated solution was further purified using either cation exchange chromatography or ammonium sulfate precipitation. For the cation exchange chromatography method, the concentrated sample was loaded onto a column equilibrated with 20 mM citrate-phosphate buffer at pH 4.8 and eluted with 200 mM citrate-phosphate buffer at pH 6.4. For the ammonium sulfate precipitation method, the concentrated sample was twice precipitated with 40% ammonium sulfate solution at pH 9.0. The yield and purity of IgY were determined by ELISA and electrophoresis. The yield of IgY from the cation exchange chromatography method was 30 to 40%, whereas that of the ammonium sulfate precipitation was 70 to 80%. The purity of IgY from the ammonium sulfate method was higher than that of the cation exchange chromatography. The cation exchange chromatography could handle only a small amount of samples, whereas the ammonium sulfate precipitation could handle a large volume of samples. This suggests that ammonium sulfate precipitation was a more efficient and useful purification method than cation exchange chromatography for the large-scale preparation of IgY from egg yolk.

  18. Fluorescence and physical properties of the organic salt 2-chloro-4-nitrobenzoate-3-ammonium-phenol

    NASA Astrophysics Data System (ADS)

    Mani, Rajaboopathi; Rietveld, Ivo B.; Nicolaï, Béatrice; Varadharajan, Krishnakumar; Louhi-Kultanen, Marjatta; Narasimhan, Surumbarkuzhali

    2015-09-01

    Organic salt 2-chloro-4-nitrobenzoate (CNBA-) 3-ammonium-phenol (AP+) exhibits fluorescence at 338 nm in solution and frontier molecular orbitals generated from TDDFT calculations indicate that the ground state and the excited state are physically separated on AP+ and CNBA-. The crystal structure and physical-chemical properties of the CNBA- · AP+ were investigated using X-ray single crystal and powder diffraction, SEM, FTIR, UV-Vis-NIR, and fluorescence spectrometry. X-ray diffraction demonstrates that the two molecules are linked via N+-H⋯O- ammonium-carboxylate interactions, as expected considering their interaction propensities. Proton transfer has been confirmed by FTIR analysis. The melting point of CNBA- · AP+ was observed at 186 °C, which is higher than pure CNBA (140 °C) or AP (120 °C). The observation of a spatially separated HOMO and LUMO possessing a narrow ΔEST = 73.3 meV and an emission in the blue region is promising as an alternative method for the production of OLED materials.

  19. Hygroscopic behavior of multicomponent organic aerosols and their internal mixtures with ammonium sulfate

    NASA Astrophysics Data System (ADS)

    Jing, B.; Tong, S. R.; Liu, Q. F.; Li, K.; Wang, W. G.; Zhang, Y. H.; Ge, M. F.

    2015-08-01

    Water soluble organic compounds (WSOCs) are important components of organics in the atmospheric fine particulate matter. Although WSOCs play an important role in the hygroscopicity of aerosols, water uptake behavior of internally mixed WSOC aerosols remains limited characterization. Here, the hygroscopic properties of single component such as levoglucosan, oxalic acid, malonic acid, succinic acid and phthalic acid and multicomponent WSOC aerosols mainly involving oxalic acid are investigated with the hygroscopicity tandem differential mobility analyzer (HTDMA). The coexisting hygroscopic species including levoglucosan, malonic acid and phthalic acid have strong influence on the hygroscopic growth and phase behavior of oxalic acid, even suppress its crystallization completely. The interactions between oxalic acid and levoglucosan are confirmed by infrared spectra. The discrepancies between measured growth factors and predictions from Extended Aerosol Inorganics Model (E-AIM) with UNIFAC method and Zdanovskii-Stokes-Robinson (ZSR) approach increase at medium and high relative humidity (RH) assuming oxalic acid in a solid state. For the internal mixture of oxalic acid with levoglucosan or succinic acid, there is enhanced water uptake at high RH due to positive chemical interactions between solutes. Organic mixture has more complex effect on the hygroscopicity of ammonium sulfate than single species. Although hygroscopic species such as levoglucosan accounts for a small fraction in the multicomponent aerosols, they may still strongly influence the hygroscopic behavior of ammonium sulfate by changing phase state of oxalic acid which plays the role of "intermediate" species. Considering the abundance of oxalic acid in the atmospheric aerosols, its mixtures with hygroscopic species may significantly promote water uptake under high RH conditions and thus affect the cloud condensation nuclei (CCN) activity, optical properties and chemical reactivity of atmospheric particles.

  20. Hygroscopic behavior of multicomponent organic aerosols and their internal mixtures with ammonium sulfate

    NASA Astrophysics Data System (ADS)

    Jing, Bo; Tong, Shengrui; Liu, Qifan; Li, Kun; Wang, Weigang; Zhang, Yunhong; Ge, Maofa

    2016-03-01

    Water-soluble organic compounds (WSOCs) are important components of organics in the atmospheric fine particulate matter. Although WSOCs play an important role in the hygroscopicity of aerosols, knowledge on the water uptake behavior of internally mixed WSOC aerosols remains limited. Here, the hygroscopic properties of single components such as levoglucosan, oxalic acid, malonic acid, succinic acid, phthalic acid, and multicomponent WSOC aerosols mainly involving oxalic acid are investigated with the hygroscopicity tandem differential mobility analyzer (HTDMA). The coexisting hygroscopic species including levoglucosan, malonic acid, and phthalic acid have a strong influence on the hygroscopic growth and phase behavior of oxalic acid, even suppressing its crystallization completely during the drying process. The phase behaviors of oxalic acid/levoglucosan mixed particles are confirmed by infrared spectra. The discrepancies between measured growth factors and predictions from Extended Aerosol Inorganics Model (E-AIM) with the Universal Quasi-Chemical Functional Group Activity Coefficient (UNIFAC) method and Zdanovskii-Stokes-Robinson (ZSR) approach increase at medium and high relative humidity (RH) assuming oxalic acid in a crystalline solid state. For the internal mixture of oxalic acid with levoglucosan or succinic acid, there is enhanced water uptake at high RH compared to the model predictions based on reasonable oxalic acid phase assumption. Organic mixture has more complex effects on the hygroscopicity of ammonium sulfate than single species. Although hygroscopic species such as levoglucosan account for a small fraction in the multicomponent aerosols, they may still strongly influence the hygroscopic behavior of ammonium sulfate by changing the phase state of oxalic acid which plays the role of "intermediate" species. Considering the abundance of oxalic acid in the atmospheric aerosols, its mixtures with hygroscopic species may significantly promote water uptake

  1. Atomic emission spectrometric determination of ephedrine, cinchonine, chlorpheniramine, atropine and diphenhydramine based on formation of ion associates with ammonium reineckate.

    PubMed

    Khalil, S

    1999-12-01

    Ion-associate complexes of ephedrine HCl (I), cinchonine HCl (II), chlorpheniramine maleate (III), atropine sulphate (IV) and diphenhydramine HCl (V) with ammonium reineckate were precipitated and their solubilities were studied as a function of pH, ionic strength and temperature. Saturated solutions of each ion-associate under the optimum precipitation conditions were prepared and the Cr ion content in the supernatant was determined. The solubility products were thus elucidated at different temperatures. A new accurate and precise method using direct current plasma-atomic emission spectrometry for the determination of the investigated drugs in pure solutions and in pharmaceutical preparations is described. The drugs can determined by the present method in the ranges 1.6-52,2.64-85.8,3.12-101.4,5.52-180.4 and 2.72-75.85 microg/ml solutions of I, II, III, IV and V, respectively.

  2. New lipophilic polyelectrolyte gels containing quaternary ammonium salt with superabsorbent capacity for organic solvents.

    PubMed

    Chen, Jian; Wang, Shuojue; Peng, Jing; Li, Jiuqiang; Zhai, Maolin

    2014-09-10

    Water and soil pollution by organic pollutants from petrochemical plants has become one of the major environmental problems in recent years. Lipophilic polyelectrolyte gels with ionic groups dissociable in nonpolar organic solvents show an enhanced swelling ability in a corresponding media attributed to the electrostatic repulsion and osmotic pressure provided by dissociated ionic groups. Here, we synthesized new lipophilic polyelectrolyte gels based on an easily available electrolyte monomer, methacryloxyethyl dimethyloctane ammonium trifluoromethanesulfonimide (MODAT), and a lipophilic neutral monomer, dodecyl acrylate by radiation-induced polymerization and cross-linking. The resultant lipophilic polyelectrolyte gels could absorb plenty of organic solvents with dielectric constants lower than 20 and exhibited a high absorbing ability at a wide range of temperatures (0-40 °C). The maximum swelling degree could reach as high as 200 g/g in some media, such as 1,2-dichloroethane (199.4 g/g) and dichloromethane (204 g/g), which was much higher than that of the nonionic gel without the addition of MODAT. Moreover, the resultant lipophilic polyelectrolyte gels could release most of the absorbed solvents within several hours and then be reused. It is expected that this new type of lipophilic polyelectrolyte gels may be a suitable candidate as organic pollutant absorbents.

  3. Analysis of an explosion accident of nitrogen trichloride in a waste liquid containing ammonium ion and platinum black.

    PubMed

    Okada, Ken; Akiyoshi, Miyako; Ishizaki, Keiko; Sato, Hiroyasu; Matsunaga, Takehiro

    2014-08-15

    Five liters of sodium hypochlorite aqueous solution (12 mass%) was poured into 300 L of liquid waste containing ammonium ion of about 1.8 mol/L in a 500 L tank in a plant area; then, two minutes later the solution exploded with a flash on March 30th, 2005. The tank cover, the fluorescent lamp and the air duct were broken by the blast wave. Thus, we have conducted 40 runs of laboratory-scale explosion tests under various conditions (solution concentrations of (NH4)2SO4 and NaClO, temperatures, Pt catalysts, pH, etc.) to investigate the causes for such an explosion. When solutions of ammonium sulfate and sodium hypochlorite are mixed in the presence of platinum black, explosions result. This is ascribable to the formation of explosive nitrogen trichloride (NCl3). In the case where it is necessary to mix these 2 solutions (ammonium sulfate and sodium hypochlorite) in the presence of platinum black, the following conditions would reduce a probability of explosion; the initial concentration of NH4(+) should be less than 3 mol/L and the pH should be higher than 6. The hypochlorite solution (in 1/10 in volume) to be added at room temperature is recommended to be less than 0.6 mol/L.

  4. First in-situ detection of the cometary ammonium ion NH_4+ (protonated ammonia NH3) in the coma of 67P/C-G near perihelion

    NASA Astrophysics Data System (ADS)

    Beth, A.; Altwegg, K.; Balsiger, H.; Berthelier, J.-J.; Calmonte, U.; Combi, M. R.; De Keyser, J.; Dhooghe, F.; Fiethe, B.; Fuselier, S. A.; Galand, M.; Gasc, S.; Gombosi, T. I.; Hansen, K. C.; Hässig, M.; Héritier, K. L.; Kopp, E.; Le Roy, L.; Mandt, K. E.; Peroy, S.; Rubin, M.; Sémon, T.; Tzou, C.-Y.; Vigren, E.

    2017-01-01

    In this paper, we report the first in-situ detection of the ammonium ion NH_4+ at 67P/Churyumov-Gerasimenko (67P/C-G) in a cometary coma, using the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) / Double Focusing Mass Spectrometer (DFMS). Unlike neutral and ion spectrometers onboard previous cometary missions, the ROSINA/DFMS spectrometer, when operated in ion mode, offers the capability to distinguish NH_4+ from H2O+ in a cometary coma. We present here the ion data analysis of mass-to-charge ratios 18 and 19 at high spectral resolution and compare the results with an ionospheric model to put the these results into context. The model confirms that the ammonium ion NH_4+ is one of the most abundant ion species, as predicted, in the coma near perihelion.

  5. Toxicity of common ions to marine organisms

    SciTech Connect

    Pillard, D.A.; DuFresne, D.L.; Evans, J.

    1995-12-31

    Produced waters from oil and gas drilling operations are typically very saline, and these may cause acute toxicity to marine organisms due to osmotic imbalances as well as to an excess or deficiency of specific common ions. In order to better understand the relationship between toxicity and ion concentration, laboratory toxicity tests were conducted using mysid shrimp (Mysidopsis bahia), sheepshead minnow (Cyprinodon variegatus), and inland silverside (Menidia beryllina). For each species the ionic concentration of standard laboratory water was proportionally increased or decreased to produce test solutions with a range of salinities. Organisms were exposed for 48 hours. Individual ions (sodium, potassium, calcium, magnetsium, strontium, chloride, bromide, sulfate, bicarbonate, and borate) were also manipulated to examine individual ion toxicity. The three test species differ in their tolerance of salinity. Mysid shrimp show a marked decrease in survival at salinities less than approximately 5 ppt. Both fish species tolerated low salinity water, however, silversides were less tolerant of saline waters (salinity greater than 40 ppt). There were also significant differences in the responses of the organisms to different ions. The results show that the salinity of the test solution may play an important role in the responses of the organisms to the produced water effluent. Predictable toxicity/ion relationships developed in this study can be used to estimate whether toxicity in a produced water is a result of common ions, salinity, or some other unknown toxicant.

  6. Cesium removal from liquid acidic wastes with the primary focus on ammonium molybdophosphate as an ion exchanger: A literature review

    SciTech Connect

    Miller, C.J.

    1995-03-01

    Many articles have been written concerning the selective removal of cesium from both acidic and alkaline defense wastes. The majority of the work performed for cesium removal from defense wastes involves alkaline feed solutions. Several different techniques for cesium removal from acidic solutions have been evaluated such as precipitation, solvent extraction, and ion exchange. The purpose of this paper is to briefly review various techniques for cesium removal from acidic solutions. The main focus of the review will be on ion exchange techniques, particularly those involving ammonium molybdophosphate as the exchanger. The pertinent literature sources are condensed into a single document for quick reference. The information contained in this document was used as an aid in determining techniques to evaluate cesium removal from the acidic Idaho Chemical Processing Plant waste matrices. 47 refs., 2 tabs.

  7. A Systematic Investigation of Quaternary Ammonium Ions as Asymmetric Phase Transfer Catalysts. Application of Quantitative Structure Activity/Selectivity Relationships

    PubMed Central

    Denmark, Scott E.; Gould, Nathan D.; Wolf, Larry M.

    2011-01-01

    While the synthetic utility of asymmetric phase transfer catalysis continues to expand, the number of proven catalyst types and design criteria remains limited. At the origin of this scarcity is a lack in understanding of how catalyst structural features affect the rate and enantioselectivity of phase transfer catalyzed reactions. Described in this paper is the development of quantitative structure-activity relationships (QSAR) and -selectivity relationships (QSSR) for the alkylation of a protected glycine imine with libraries of quaternary ammonium ion catalysts. Catalyst descriptors including ammonium ion accessibility, interfacial adsorption affinity, and partition coefficient were found to correlate meaningfully with catalyst activity. The physical nature of the descriptors was rationalized through differing contributions of the interfacial and extraction mechanisms to the reaction under study. The variation in the observed enantioselectivity was rationalized employing a comparative molecular field analysis (CoMFA) using both the steric and electrostatic fields of the catalysts. A qualitative analysis of the developed model reveals preferred regions for catalyst binding to afford both configurations of the alkylated product. PMID:21446723

  8. Organic ion exchange resin separation methods evaluation

    SciTech Connect

    Witwer, K.S.

    1998-05-27

    This document describes testing to find effective methods to separate Organic Ion Exchange Resin (OIER) from a sludge simulant. This task supports a comprehensive strategy for treatment and processing of K-Basin sludge. The simulant to be used resembles sludge that has accumulated in the 105KE and 105KW Basins in the 1OOK area of the Hanford Site. The sludge is an accumulation of fuel element corrosion products, organic and inorganic ion exchange materials, canister gasket materials, iron and aluminum corrosion products, sand, dirt, and other minor amounts of organic matter.

  9. Gas phase hydration of organic ions.

    PubMed

    Momoh, Paul O; El-Shall, M Samy

    2008-08-28

    In this work, we study the hydration phenomenon on a molecular level in the gas phase where a selected number of water molecules can interact with the organic ion of interest. The stepwise binding energies (DeltaH degrees (n-1,n)) of 1-7 water molecules to the phenyl acetylene cation are determined by equilibrium measurements using an ion mobility drift cell. The stepwise hydration energies DeltaH degrees (n-1,n) are nearly constant at 39.7 +/- 6.3 kJ mol(-1) from n = 1 to 7. The entropy change is larger in the n = 7 step, suggesting cyclic or cage-like water structures. No water addition is observed on the ionized phenyl acetylene trimer consistent with cyclization of the trimer ion to form triphenyl benzene cations C(24)H(18) (+) which are expected to interact weakly with the water molecules due to steric interactions and the delocalization of the charge on the large organic ion. The work demonstrates that hydration studies of organic ions can provide structural information on the organic ions.

  10. Sources of polyatomic ions of organic liquids.

    PubMed

    Takaoka, G H; Takeuchi, M; Ryuto, H

    2010-02-01

    We have developed two types of liquid ion sources, one of which was a polyatomic ion source using liquid organic materials with a high-vapor pressure. Liquid materials such as octane and ethanol could be heated up to a maximum temperature of 100 degrees C, and the vapors were introduced into an ion source. They were ionized by an electron bombardment method and extracted from the ionizer. The ion current obtained at an extraction voltage of 2 kV was 230 microA for octane and several fragment ions such as alkyl ions were produced. On the other hand, another type of polyatomic ion source using alkyl naphthalene mixed with ionic liquid such as imidazolium dicyanamide has been developed. Instead of the electron bombardment method, a high-electric field method was used for the ion-emission from a sharp tip, because the vapor pressure of the liquid materials was relatively low. The threshold voltage was approximately 4.5 kV and the ion current of approximately 250 nA was obtained at an extraction voltage of 9.5 kV.

  11. Ion surface treatments on organic materials

    NASA Astrophysics Data System (ADS)

    Iwaki, Masaya

    2001-04-01

    A study has been made of surface modification of various organic materials by ion bombardment or implantation to make the surface properties of high and multiple functions in RIKEN. Substrates used were polyimide (PI), polyacetylene, polytetrafluoroethylene (PTFE), polystyrene (PS), silicone rubber, various kinds of proteins and so on. Bombarded or implanted ions were inert gas elements, chemically active gaseous elements and metallic elements. Surface properties such as electrical conductivity, wettability and cell adhesion of implanted layers have been investigated. Surface characterization of implanted materials has been carried out by means of transmission electron microscopy, laser Raman spectroscopy, X-ray photoelectron spectroscopy and Rutherford backscattering spectroscopy. In this paper, studies in RIKEN are reviewed of electrical conductivity, optical absorbance, wettability and cell adhesion depending on current densities and doping elements. Applications of ion bombardment to biomedical materials are introduced using cell adhesion control. It is concluded that ion bombardment or implantation is useful to change and control surface properties of various organic materials.

  12. In situ activity and spatial organization of anaerobic ammonium-oxidizing (anammox) bacteria in biofilms.

    PubMed

    Kindaichi, Tomonori; Tsushima, Ikuo; Ogasawara, Yuji; Shimokawa, Masaki; Ozaki, Noriatsu; Satoh, Hisashi; Okabe, Satoshi

    2007-08-01

    We investigated autotrophic anaerobic ammonium-oxidizing (anammox) biofilms for their spatial organization, community composition, and in situ activities by using molecular biological techniques combined with microelectrodes. Results of phylogenetic analysis and fluorescence in situ hybridization (FISH) revealed that "Brocadia"-like anammox bacteria that hybridized with the Amx820 probe dominated, with 60 to 92% of total bacteria in the upper part (<1,000 microm) of the biofilm, where high anammox activity was mainly detected with microelectrodes. The relative abundance of anammox bacteria decreased along the flow direction of the reactor. FISH results also indicated that Nitrosomonas-, Nitrosospira-, and Nitrosococcus-like aerobic ammonia-oxidizing bacteria (AOB) and Nitrospira-like nitrite-oxidizing bacteria (NOB) coexisted with anammox bacteria and accounted for 13 to 21% of total bacteria in the biofilms. Microelectrode measurements at three points along the anammox reactor revealed that the NH(4)(+) and NO(2)(-) consumption rates decreased from 0.68 and 0.64 micromol cm(-2) h(-1) at P2 (the second port, 170 mm from the inlet port) to 0.30 and 0.35 micromol cm(-2) h(-1) at P3 (the third port, 205 mm from the inlet port), respectively. No anammox activity was detected at P4 (the fourth port, 240 mm from the inlet port), even though sufficient amounts of NH(4)(+) and NO(2)(-) and a high abundance of anammox bacteria were still present. This result could be explained by the inhibitory effect of organic compounds derived from biomass decay and/or produced by anammox and coexisting bacteria in the upper parts of the biofilm and in the upstream part of the reactor. The anammox activities in the biofilm determined by microelectrodes reflected the overall reactor performance. The several groups of aerobic AOB lineages, Nitrospira-like NOB, and Betaproteobacteria coexisting in the anammox biofilm might consume a trace amount of O(2) or organic compounds, which

  13. Phase transitions and phase miscibility of mixed particles of ammonium sulfate, toluene-derived secondary organic material, and water.

    PubMed

    Smith, Mackenzie L; You, Yuan; Kuwata, Mikinori; Bertram, Allan K; Martin, Scot T

    2013-09-12

    The phase states of atmospheric particles influence their roles in physicochemical processes related to air quality and climate. The phases of particles containing secondary organic materials (SOMs) are still uncertain, especially for SOMs produced from aromatic precursor gases. In this work, efflorescence and deliquescence phase transitions, as well as phase separation, in particles composed of toluene-derived SOM, ammonium sulfate, and water were studied by hygroscopic tandem differential mobility analysis (HTDMA) and optical microscopy. The SOM was produced in the Harvard Environmental Chamber by photo-oxidation of toluene at chamber relative humidities of <5 and 40%. The efflorescence and deliquescence relative humidities (ERH and DRH, respectively, studied by HTDMA) of ammonium sulfate decreased as the SOM organic fraction ε in the particle increased, dropping from DRH = 80% and ERH = 31% for ε = 0.0 to DRH = 58% and ERH = 0% for ε = 0.8. For ε < 0.2, the DRH and ERH to first approximation did not change with the organic volume fraction. This observation is consistent with independent behaviors for ε < 0.2 of water-infused toluene-derived SOM and aqueous ammonium sulfate, suggesting phase immiscibility between the two. Optical microscopy of particles prepared for ε = 0.12 confirmed phase separation for RH < 85%. For ε from 0.2 to 0.8, the DRH and ERH values steadily decreased, as studied by HTDMA. This result is consistent with one-phase mixing of ammonium sulfate, SOM, and water. Optical microscopy for particles of ε = 0.8 confirmed this result. Within error, increased exposure times of the aerosol in the HTDMA from 0.5 to 30 s affected neither the ERH(ε) nor DRH(ε) curves, implying an absence of kinetic effects on the observations over the studied time scales. For ε > 0.5, the DRH values of ammonium sulfate in mixtures with SOM produced at <5% RH were offset by -3 to -5% RH compared to the results for SOM produced at 40% RH, suggesting differences

  14. Effect of natural zeolite on methane production for anaerobic digestion of ammonium rich organic sludge.

    PubMed

    Tada, Chika; Yang, Yingnan; Hanaoka, Toshiaki; Sonoda, Akinari; Ooi, Kenta; Sawayama, Shigeki

    2005-03-01

    The effect of an inorganic additive on the methane production from NH(4+)-rich organic sludge during anaerobic digestion was investigated using different kinds of inorganic adsorbent zeolites (mordenite, clinoptilolite, zeolite 3A, zeolite 4A), clay mineral (vermiculite), and manganese oxides (hollandite, birnessite). The additions of inorganic materials resulted in significant NH4+ removals from the natural organic sludge ([NH4+]=1, 150 mg N/l), except for the H-type zeolite 3A and birnessite. However, an enhanced methane production was only achieved using natural mordenite. Natural mordenite also enhanced the methane production from the sludge with a markedly high NH4+ concentration (4500 mg N/l) during anaerobic digestion. Chemical analyses of the sludge after the digestion showed considerable increases in the Ca2+ and Mg2+ concentrations in the presence of natural mordenite, but not with synthetic zeolite 3A. The effect of Ca2+ or Mg2+ addition on the methane production was studied using Na(+)-exchanges mordenite and Ca2+ or Mg(2+)-enriched sludge. The simultaneous addition of Ca2+ ions and Na(+)-exchanged mordenite enhanced the methane production; the amount of produced methane was about three times greater than that using only the Na(+)-exchanged mordenite. In addition, comparing the methane production by the addition of natural mordenite or Ca2+ ions, the methane production with natural mordenite was about 1.7 times higher than that with only Ca2+ ions. The addition of 5% and 10% natural mordenite were suitable condition for obtaining a high methane production. These results indicated that the Ca2+ ions, which are released from natural mordenite by a Ca2+/NH4+ exchange, enhanced the methane production of the organic waste at a high NH4+ concentration. Natural mordenite has a synergistic effect on the Ca2+ supply as well on the NH4+ removal during anaerobic digestion, which is effective for the mitigation of NH4+ inhibition against methane production.

  15. Ammonium attenuation in aquifer material impacted with high levels of organic wastes. Final report

    SciTech Connect

    Brown, T.H.

    1997-08-01

    Total concentrations of ammonium (NH{sub 4}{sup +1}) have been found to exceed the State of Wyoming ground water quality standard for Class 1 aquifers near Torrington, Wyoming. The cause of the NH{sub 4}{sup +1} contamination is thought to be associated with fertilizer use and/or the leaching of organics into the ground water from impoundments holding wastes from sugar beet processing. This type of contamination could be expected from other industrial processes, including those associated with the use of fossil fuels. In an initial step in understanding and solving the ground water contamination problem, Western Research Institute (WRI) conducted a laboratory investigation to understand the aquifer system as it relates to the chemistry of NH{sub 4}{sup +1} as it moves through the aquifer material. The data collected during the attenuation tests do provide an indication that the attenuation of NH{sub 4}{sup +1} in the ground water system will occur. In addition, the results show the redox condition of the site and the possible chemical reactions that are influencing the ground water quality.

  16. Effect of dissolved organic matter on ammonium sorption kinetics and equilibrium to Chinese clinoptilolite.

    PubMed

    Zhang, Ying; Bi, Erping

    2012-01-01

    In the in-situ remediation of ammonium (NH4+) in groundwater by a sequential reactive barrier filled with zeolite, it is of great importance to understand the mechanisms of NH4+ sorption to zeolite. In this study, the effect of dissolved natural organic matter on NH4+ sorption to natural Chinese clinoptilolite was studied by batch experiments taking humic acid (HA) as a model substance. The surface of clinoptilolite was characterized by scanning electronic microscopy (SEM). A needle cluster of sorbed HA could be observed on the surface of the clinoptilolite. The negative effect of HA on NH4+ sorption is thought to be their competition for sorption sites, the surface coverage and blockage of the pores of clinoptilolite by HA. The fitting results of kinetic sorption data indicated that the rate-controlling step for NH4+ sorption by clinoptilolite in both NH4+ and NH4+ + HA systems is the heterogeneous chemisorption. The existence of HA (10 mg/L) significantly reduced the initial sorption rate of NH4+, but the effect of a further concentration increase of HA was slight. The effect of HA on maximum sorption capacity was found to be insignificant in the experiments. A high aqueous Ca2+ concentration can decrease the negative effect of HA on NH4+ sorption by precipitation of calcium humate.

  17. Ultrathin ammonium heptamolybdate films as efficient room-temperature hole transport layers for organic solar cells.

    PubMed

    Qiu, Weiming; Hadipour, Afshin; Müller, Robert; Conings, Bert; Boyen, Hans-Gerd; Heremans, Paul; Froyen, Ludo

    2014-09-24

    Ammonium heptamolybdate (NH4)6Mo7O24·4H2O (AHM) and its peroxo derivatives are analyzed as solution-processed room temperature hole transport layer (HTL) in organic solar cells. Such AHM based HTLs are investigated in devices with three different types of active layers, i.e., solution-processed poly(3-hexylthiophene)/[6,6]-phenyl C61-butyric acid methyl ester(P3HT/PC60BM), poly[N-9'-heptadecanyl-2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole)]/[6,6]-phenyl C70-butyric acid methyl ester(PCDTBT/PC70BM) and evaporated small molecule chloro(subphthalocyaninato)boron(III) (SubPc)/C60. By virtue of their high work functions, AHM based HTLs outperform the commonly used poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) HTL for devices employing deep HOMO level active materials. Moreover, devices using AHM based HTLs can achieve higher short circuit current (Jsc) than the ones with evaporated molybdenum oxide(eMoO3), and thus better power conversion efficiency (PCE). In addition, P3HT/PC60BM devices with AHM based HTLs show air stability comparable to those with eMoO3, and much better than the ones with PEDOT:PSS.

  18. Sorption of doubly charged metal ions from ammonium fluoride solutions by KFP-23 cation-exchange resin

    SciTech Connect

    Ganyaev, V.P.; Pimneva, L.A.; Pakholkov, V.S.

    1982-10-20

    This report examines the results of a study of sorption of a number of doubly charged cations by the macroporous cation-exchange KFP-12 from 0.1 N MeF/sub 2/ solutions containing NH/sub 4/F in concentrations from 0 to 3.0 M. As the result of an investigation of the sorption, under dynamic conditions, of copper, zinc, cadmium, manganese, cobalt, and nickel ions from ammonium fluoride solutions by KFP-12 cation-exchange resin in the influence of the ionic form (H/sup +/ or NH/sub 4//sup +/) of the resin and of the NH/sub 4/F concentration on the degree of sorption and on the breakthrough capacity was established. The character of bonding and coordination of the sorbed cations with the ionic groups of the resin has been established. The possibilty of thorough purification of ammonium fluoride and (NH/sub 4/)/sub 2/BeF/sub 4/ solutions with the aid of KFP-12 resin in NH/sub 4//sup +/ form has been demonstrated. The purification co-efficients were calculated.

  19. Nitrate and ammonium ions removal from groundwater by a hybrid system of zero-valent iron combined with adsorbents.

    PubMed

    Ji, Min-Kyu; Park, Won-Bae; Khan, Moonis Ali; Abou-Shanab, Reda A I; Kim, Yongje; Cho, Yunchul; Choi, Jaeyoung; Song, Hocheol; Jeon, Byong-Hun

    2012-04-01

    Nitrate (NO(3)(-)) is a commonly found contaminant in groundwater and surface water. It has created a major water quality problem worldwide. The laboratory batch experiments were conducted to investigate the feasibility of HCl-treated zero-valent iron (Fe(0)) combined with different adsorbents as hybrid systems for simultaneous removal of nitrate (NO(3)(-)) and ammonium (NH(4)(+)) ions from aqueous solution. The maximum NO(3)(-) removal in combined Fe(0)-granular activated carbon (GAC), Fe(0)-filtralite and Fe(0)-sepiolite systems was 86, 96 and 99%, respectively, at 45 °C for 24 h reaction time. The NO(3)(-) removal rate increased with the increase in initial NO(3)(-) concentration. The NO(3)(-) removal efficiency by hybrid systems was in the order of sepiolite > filtralite > GAC. The NH(4)(+) produced during the denitrification process by Fe(0) was successfully removed by the adsorbents, with the removal efficiency in the order of GAC > sepiolite > filtralite. Results of the present study suggest that the use of a hybrid system could be a promising technology for achieving simultaneous removal of NO(3)(-) and NH(4)(+) ions from aqueous solution.

  20. Synthesis and Characterization of Perfluoro Quaternary Ammonium Ion Exchange Membranes for Fuel Cell Applications

    DTIC Science & Technology

    2012-01-01

    TERMS Perfluoroinated polymer; anion exchange membrane; morphology; base stability Mellisa A. Vandiver, Soenke Seifert, Matthew W. Liberatore, Andrew...humidities. Better understanding of the role of water and polymer morphology on the ion conduction and stability of AEMs is necessary for practical AEM fuel...sufficient chemical and mechanical stability (5, 10) For these reasons PFSAs remain the benchmark comparison for all new PEMs and AEMs (1, 11). The

  1. Ion conducting organic/inorganic hybrid polymers

    NASA Technical Reports Server (NTRS)

    Meador, Maryann B. (Inventor); Kinder, James D. (Inventor)

    2010-01-01

    This invention relates to a series of organic/inorganic hybrid polymers that are easy to fabricate into dimensionally stable films with good ion-conductivity over a wide range of temperatures for use in a variety of applications. The polymers are prepared by the reaction of amines, preferably diamines and mixtures thereof with monoamines with epoxy-functionalized alkoxysilanes. The products of the reaction are polymerized by hydrolysis of the alkoxysilane groups to produce an organic-containing silica network. Suitable functionality introduced into the amine and alkoxysilane groups produce solid polymeric membranes which conduct ions for use in fuel cells, high-performance solid state batteries, chemical sensors, electrochemical capacitors, electro-chromic windows or displays, analog memory devices and the like.

  2. Source apportionment of ammonium and nitrate ion using nitrogen stable isotope

    NASA Astrophysics Data System (ADS)

    Kawashima, H.

    2013-12-01

    Suspended particulate matter (SPM), defined to particle size as 100 % cut-off aerodynamic diameter at 10 μm, has adverse effects on human health. In these years, stable isotope ratio of small sample volume can be analyzed high precision by isotope ratio mass spectrometry coupling with elemental analyzer. Recently some fields are using stable isotope ratio. For environmental field, it is expected such as powerful tool for source identification and understanding mechanism. But the existed researches intended for stable nitrogen isotope (δ15N) of particulate matter have been limited. We try to analysis δ15N-ammonium (δ15N-NH4+) and nitrate (δ15N-NO3-) of SPM, to estimate source of NH4+ and NO3- of SPM. Average δ15N-NH4+ and δ15N-NO3- of SPM in Akita prefecture, Japan were 15.9 ‰ (1.3‰ to 38.5 ‰) and - 0.7 ‰ (-4.6 ‰ to 4.8 ‰), respectively. Although δ15N-NH4+ do not show seasonal trend, δ15N-NO3- increased in winter markedly and decreasing in summer. In generally, the dominant origin of NO3- of SPM is produced from NOx emitted by combustion of some fuel and NO by agriculture source. Heaton (1990) summarized that δ15N-NOx is very different by temperature of combustion. They insisted that δ15N-NOx values are between -13 ‰ to -2 ‰ over 2000 °C (e.g. vehicle engine) and 6 ‰ to 13 ‰ under 1300 °C (e.g. coal combustion). Therefore, the reason of the winter high trend in this study might be combustion process such as coal combustion source. Moreover, the baseline might be made by vehicle sources. In addition, the reason of decreasing in summer seemed to be affected very low δ15N-NO of fertilizer and urea indicated by Li and Wang (2008). Bacteria were activated in summer, and NO from fertilizer and urea was emitted. This summary seemed to be very reasonable.

  3. Sorption of uranium(VI) ions from hydrochloric acid and ammonium chloride solutions by anion exchangers

    SciTech Connect

    Pakholkov, V.S.; Denisova, L.A.; Rychkov, V.N.; Kurnosenko, N.A.

    1988-01-01

    The sorption of macroscopic quantities of uranium from solutions of UO/sub 2/Cl/sub 2/ containing HCl and NH/sub 4/Cl in concentrations from 0.0 to 6.0 M by the AV-17 x 8, AV-16G, EDE-10P, AN-31, AN-2F, AN22, and AN-251 anion exchangers has been investigated under static conditions. The sorption isotherms are described by an equation similar to Freundlich's equation: K/sub d/ = K tilde x C/sub eq/sup 1/z/ or log K/sub d/ = log K tilde + 1/z x log C/sub eq/. Equations describing the dependence of the sorbability (or K/sub d/) on the equilibrium concentration of uranium in the solution have been obtained with the aid of the least-squares method. Conclusions regarding the chemistry of the exchange of uranium ions on anion exchangers in chloride solutions have been drawn on the basis of the UV spectra of the original solutions and the IR spectra of the ion exchangers obtained in this work, as well as the established general laws governing sorption.

  4. The Organization of High-Affinity Ammonium Uptake in Arabidopsis Roots Depends on the Spatial Arrangement and Biochemical Properties of AMT1-Type Transporters[W

    PubMed Central

    Yuan, Lixing; Loqué, Dominique; Kojima, Soichi; Rauch, Sabine; Ishiyama, Keiki; Inoue, Eri; Takahashi, Hideki; von Wirén, Nicolaus

    2007-01-01

    The AMMONIUM TRANSPORTER (AMT) family comprises six isoforms in Arabidopsis thaliana. Here, we describe the complete functional organization of root-expressed AMTs for high-affinity ammonium uptake. High-affinity influx of 15N-labeled ammonium in two transposon-tagged amt1;2 lines was reduced by 18 to 26% compared with wild-type plants. Enrichment of the AMT1;2 protein in the plasma membrane and localization of AMT1;2 promoter activity in the endodermis and root cortex indicated that AMT1;2 mediates the uptake of ammonium entering the root via the apoplasmic transport route. An amt1;1 amt1;2 amt1;3 amt2;1 quadruple mutant (qko) showed severe growth depression under ammonium supply and maintained only 5 to 10% of wild-type high-affinity ammonium uptake capacity. Transcriptional upregulation of AMT1;5 in nitrogen-deficient rhizodermal and root hair cells and the ability of AMT1;5 to transport ammonium in yeast suggested that AMT1;5 accounts for the remaining uptake capacity in qko. Triple and quadruple amt insertion lines revealed in vivo ammonium substrate affinities of 50, 234, 61, and 4.5 μM for AMT1;1, AMT1;2, AMT1;3, and AMT1;5, respectively, but no ammonium influx activity for AMT2;1. These data suggest that two principle means of achieving effective ammonium uptake in Arabidopsis roots are the spatial arrangement of AMT1-type ammonium transporters and the distribution of their transport capacities at different substrate affinities. PMID:17693533

  5. Mixtures of quaternary ammonium compounds and anionic organic compounds in the aquatic environment: Elimination and biodegradability in the closed bottle test monitored by LC-MS/MS.

    PubMed

    Sütterlin, H; Alexy, R; Coker, A; Kümmerer, K

    2008-06-01

    Quaternary ammonium compounds (QACs) are widely used as disinfectants, detergents and fabric softeners. Anionic detergents are one of the most widely used chemical substances. QACs and anionic surfactants can form ionic pairs. In the present study we investigated the biodegradability of QACs in the presence of different anionic surfactants. The biodegradability of three QACs, namely benzalkonium chloride (BAC), didecyldimethylammonium chloride (DDMAC) and ethacridine lactate (EL), when applied as single substances and in combination with anionic surfactants such as benzene sulfonic acid (BSA), LAS, naphthalene sulfonic acid (NSA) and sodium dodecylsulfonate (SDS) was studied applying the closed bottle test (CBT) [OECD 301D, 1992. Guidelines for Testing of Chemicals. Closed bottle test. Organisation of Economic Cooperation and Development, Paris] at a ratio of 1:1 (mol:mol). Biodegradation was monitored by measuring oxygen concentration in the test vessels with an oxygen electrode in accordance with international standard methods [ISO 5414, 1990. Water quality - determination of dissolved oxygen. In: German Standard Methods for the Examination of Water, Wastewater and Sludge. VCH Verlagsgesellschaft, Weinheim, New York, Basel Cambridge]. Primary elimination of the QACs and of LAS was monitored by LC-MS/MS. There was little biodegradability of the QACs as either single compounds or in the presence of organic counter ions. The biodegradability of the organic counter ions was lower in the presence of QACs as compared to the single substances. Primary elimination of the QACs by sorption took place.

  6. Ammonium Fluoride Mediated Synthesis of Anhydrous Metal Fluoride-Mesoporous Carbon Nanocomposites for High-Performance Lithium Ion Battery Cathodes.

    PubMed

    Chun, Jinyoung; Jo, Changshin; Sahgong, Sunhye; Kim, Min Gyu; Lim, Eunho; Kim, Dong Hyeon; Hwang, Jongkook; Kang, Eunae; Ryu, Keun Ah; Jung, Yoon Seok; Kim, Youngsik; Lee, Jinwoo

    2016-12-28

    Metal fluorides (MFx) are one of the most attractive cathode candidates for Li ion batteries (LIBs) due to their high conversion potentials with large capacities. However, only a limited number of synthetic methods, generally involving highly toxic or inaccessible reagents, currently exist, which has made it difficult to produce well-designed nanostructures suitable for cathodes; consequently, harnessing their potential cathodic properties has been a challenge. Herein, we report a new bottom-up synthetic method utilizing ammonium fluoride (NH4F) for the preparation of anhydrous MFx (CuF2, FeF3, and CoF2)/mesoporous carbon (MSU-F-C) nanocomposites, whereby a series of metal precursor nanoparticles preconfined in mesoporous carbon were readily converted to anhydrous MFx through simple heat treatment with NH4F under solventless conditions. We demonstrate the versatility, lower toxicity, and efficiency of this synthetic method and, using XRD analysis, propose a mechanism for the reaction. All MFx/MSU-F-C prepared in this study exhibited superior electrochemical performances, through conversion reactions, as the cathode for LIBs. In particular, FeF3/MSU-F-C maintained a capacity of 650 mAh g(-1)FeF3 across 50 cycles, which is ∼90% of its initial capacity. We expect that this facile synthesis method will trigger further research into the development of various nanostructured MFx for use in energy storage and other applications.

  7. Creatinine and urea biosensors based on a novel ammonium ion-selective copper-polyaniline nano-composite.

    PubMed

    Zhybak, M; Beni, V; Vagin, M Y; Dempsey, E; Turner, A P F; Korpan, Y

    2016-03-15

    The use of a novel ammonium ion-specific copper-polyaniline nano-composite as transducer for hydrolase-based biosensors is proposed. In this work, a combination of creatinine deaminase and urease has been chosen as a model system to demonstrate the construction of urea and creatinine biosensors to illustrate the principle. Immobilisation of enzymes was shown to be a crucial step in the development of the biosensors; the use of glycerol and lactitol as stabilisers resulted in a significant improvement, especially in the case of the creatinine, of the operational stability of the biosensors (from few hours to at least 3 days). The developed biosensors exhibited high selectivity towards creatinine and urea. The sensitivity was found to be 85 ± 3.4 mAM(-1)cm(-2) for the creatinine biosensor and 112 ± 3.36 mAM(-1)cm(-2) for the urea biosensor, with apparent Michaelis-Menten constants (KM,app), obtained from the creatinine and urea calibration curves, of 0.163 mM for creatinine deaminase and 0.139 mM for urease, respectively. The biosensors responded linearly over the concentration range 1-125 µM, with a limit of detection of 0.5 µM and a response time of 15s. The performance of the biosensors in a real sample matrix, serum, was evaluated and a good correlation with standard spectrophotometric clinical laboratory techniques was found.

  8. Determination of ammonium ion by fluorometry or spectrophotometry after on-line derivatization with o-phthalaldehyde

    NASA Technical Reports Server (NTRS)

    Goyal, S. S.; Rains, D. W.; Huffaker, R. C.

    1988-01-01

    A fast, sensitive, simple, and highly reproducible method for routine assay of ammonium ion (NH4+) was developed by using HPLC equipment. The method is based on the reaction of NH4+ with o-phthalaldehyde (OPA) in the presence of 2-mercaptoethanol. After an on-line derivatization, the resulting NH4(+)-OPA product was quantified by using fluorometric or spectrophotometric detection. For fluorometric detection, the excitation and emission wavelengths were 410 and 470 nm, respectively. The spectrophotometric detection was made by measuring absorbance at 410 nm. Results on the effects of OPA-reagent composition and pH, reaction temperature, sample matrix, and linearity of the assay are presented. Even though it took about 2 min from the time of sample injection to the appearance of sample peak, sample injections could be overlapped at an interval of about 1 min. Thus, the actual time needed for analysis was about 1 min per assay. The method can be used in a fully automated mode by using an autosampler injector.

  9. A UHPLC method for the simultaneous analysis of biogenic amines, amino acids and ammonium ions in beer.

    PubMed

    Redruello, Begoña; Ladero, Victor; Del Rio, Beatriz; Fernández, María; Martin, M C; Alvarez, Miguel A

    2017-02-15

    This paper reports a novel UHPLC method for simultaneously quantifying nine biogenic amines, 21 amino acids, and ammonium ions, in beer. Precision values of standard curves slopes were lower than 3.4% and recovery was between 85% and 106%, indicating the absence of matrix effect. Linear calibration curves were obtained for analyte concentrations between two and four orders of magnitude (R(2)>0.996). Repeatability tests returned mean variations of 3.2% and 0.5% for beer and a standard solution, respectively. Sensitivity ranged between 0.03mg/L and 0.63mg/L for the biogenic amines, and 0.05mg/L and 5.19mg/L for other compounds. Original data on the habitual presence of ethanolamine in beers are presented. The method allows for more samples to be assayed per unit time, it uses less solvent than other techniques and therefore reduces costs and the associated waste. It could be a valuable tool for monitoring the safety and quality of beers.

  10. Hydrothermal synthesis and structural characterization of ammonium ion-templated lanthanide(III) carboxylate-phosphonates

    PubMed Central

    Ayi, Ayi A.; Kinnibrugh, Tiffany L.; Clearfield, Abraham

    2014-01-01

    Using N-(phosphonomethyl) iminodiacetic acid (H4PMIDA), as a complexing agent, two new complexes, (NH4)La(PMIDA)(H2O)•H2O, 1 and (NH4)Yb(PMIDA), 2 have been synthesized hydrothermally. In both compounds, the metal ions are trapped by a three five-membered chelate rings by the chelating PMIDA anions giving a tricapped trigonal prismatic LaO8N and monocapped trigonal prismatic YbO6N geometries for 1 and 2, respectively. The structure of 1 consists of La(PMIDA)(H2O) chelating units, linked together by the phosphonate oxygen atoms O1 and O3 to form a chain along the c-axis. The chains are then connected together by the bridging phosphonate oxygen O2 to form a 2D layered structure with alternating 4- and 8-membered apertures. The structure of 2 consists Yb(PMIDA) chelating units, which are connected by alternating bridging carboxylate and phosphonate groups along the [010] direction forming chains with a corrugated pattern. The third phosphonate oxygen bridges the chains together along the [001] direction to build the two-dimensional layer with 4- and 6-membered apertures in the bc-plane. Under excitation of 330 nm, compound 2 shows a broad emission band at λmax = 460 nm. This emission is essentially in the blue luminescent region, which corresponds to ligand centered fluorescence. PMID:25414845

  11. Analysis of nine food additives in red wine by ion-suppression reversed-phase high-performance liquid chromatography using trifluoroacetic acid and ammonium acetate as ion-suppressors.

    PubMed

    Zhao, Yong-Gang; Chen, Xiao-Hong; Yao, Shan-Shan; Pan, Sheng-Dong; Li, Xiao-Ping; Jin, Mi-Cong

    2012-01-01

    A reversed-phase high-performance liquid chromatography (RP-HPLC) method was developed for the simultaneous determination of nine food additives, i.e., acesulfame, saccharin, caffeine, aspartame, benzoic acid, sorbic acid, stevioside, dehydroacetic acid and neotame in red wine. The effects of ion-suppressors, i.e., trifluoroacetic acid (TFA) and ammonium acetate (AmAc) on retention behavior of nine food additives in RP-HPLC separation were discussed in detail. The relationships between retention factors of solutes and volume percent of ion-suppressors in the mobile-phase systems of acetonitrile-TFA aqueous solution and acetonitrile-TFA-AmAc aqueous solution were quantitatively established, respectively. The results showed that the ion suppressors had not only an ion suppression effect, but also an organic modification effect on the acidic analytes. The baseline separation of nine food additives was completed by a gradient elution with acetonitrile-TFA(0.01%, v/v)-AmAc(2.5 mmol L(-1)) aqueous solution as the mobile phase. The recoveries were between 80.2 - 99.5% for all analytes with RSDs in the range of 1.5 - 8.9%. The linearities were in the range of 0.2 - 100.0 mg L(-1) with determination coefficients (r(2)) higher than 0.9991 for all analytes. The limits of quantification (LOQs) were between 0.53 - 0.99 mg L(-1). The applicability of the proposed method to detect and quantify food additives has been demonstrated in the analysis of 30 real samples.

  12. Theoretical problems associated with the use of acetic anhydride as a co-solvent for the non-aqueous titration of hydrohalides of organic bases and quaternary ammonium salts.

    PubMed

    Völgyi, Gergely; Béni, Szabolcs; Takács-Novák, Krisztina; Görög, Sándor

    2010-01-05

    A potentiometric titration study of organic base hydrohalides and quaternary ammonium salts using perchloric acid as the titrant and a mixture of acetic anhydride and acetic acid as the solvent was carried out and the titration mixture was analysed by NMR in order to clarify the chemistry of the reactions involved. It was found that in contrast to the general belief the formation of acetyl halides and titratable free acetate ion does not take place prior to the titration but NMR spectra proved the formation of acetyl halides in the course of the titration. This observation and the fact that the shape of the titration curves depends on the nature of the hydrohaloic acid bound to the base or of the anion in the quaternary ammonium salts led to the conclusion that the titrating agent is acetyl perchlorate formed in situ during the titration. Equations of the reactions involved in the titration process are shown in the paper.

  13. Ion-Conducting Organic/Inorganic Polymers

    NASA Technical Reports Server (NTRS)

    Kinder, James D.; Meador, Mary Ann B.

    2007-01-01

    Ion-conducting polymers that are hybrids of organic and inorganic moieties and that are suitable for forming into solid-electrolyte membranes have been invented in an effort to improve upon the polymeric materials that have been used previously for such membranes. Examples of the prior materials include perfluorosulfonic acid-based formulations, polybenzimidazoles, sulfonated polyetherketone, sulfonated naphthalenic polyimides, and polyethylene oxide (PEO)-based formulations. Relative to the prior materials, the polymers of the present invention offer greater dimensional stability, greater ease of formation into mechanically resilient films, and acceptably high ionic conductivities over wider temperature ranges. Devices in which films made of these ion-conducting organic/inorganic polymers could be used include fuel cells, lithium batteries, chemical sensors, electrochemical capacitors, electrochromic windows and display devices, and analog memory devices. The synthesis of a polymer of this type (see Figure 1) starts with a reaction between an epoxide-functionalized alkoxysilane and a diamine. The product of this reaction is polymerized by hydrolysis and condensation of the alkoxysilane group, producing a molecular network that contains both organic and inorganic (silica) links. The silica in the network contributes to the ionic conductivity and to the desired thermal and mechanical properties. Examples of other diamines that have been used in the reaction sequence of Figure 1 are shown in Figure 2. One can use any of these diamines or any combination of them in proportions chosen to impart desired properties to the finished product. Alternatively or in addition, one could similarly vary the functionality of the alkoxysilane to obtain desired properties. The variety of available alkoxysilanes and diamines thus affords flexibility to optimize the organic/inorganic polymer for a given application.

  14. Adsorption and transformation of ammonium ion in a loose-pore geothermal reservoir: Batch and column experiments.

    PubMed

    Zhao, Li; Li, Yanli; Wang, Shidong; Wang, Xinyi; Meng, Hongqi; Luo, Shaohe

    2016-09-01

    Adsorption kinetics and transformation process of ammonium ion (NH4(+)) were investigated to advance the understanding of N cycle in a low-temperature loose-pore geothermal reservoir. Firstly, batch experiments were performed in order to determine the sorption capacity and the kinetic mechanism of NH4(+) onto a loose-pore geothermal reservoir matrix. Then column experiments were carried out at temperatures from 20°C to 60°C in order to determine the transport parameters and transformation mechanism of NH4(+) in the studied matrix. The results showed that the adsorption process of NH4(+) onto the porous media well followed the pseudo-second-order model. No obvious variation of hydrodynamic dispersion coefficient (D) and retardation factor (R) was observed at different transport distances at a Darcy's flux of 2.27cm/h, at which nitrification could be neglected. The simulated D obtained by the CDE model in CXTFIT2.1 increased with temperature while R decreased with temperature, indicating that the adsorption capacity of NH4(+) onto the matrix decreased with the increasing of temperature. When the Darcy's flux was decreased to 0.014cm/h, only a little part of NH4(+) could be transformed to nitrate, suggesting that low density of nitrifiers existed in the simulated loose-pore geothermal reservoir. Although nitrification rate increased with temperature in the range of 20°C to 60°C, it was extremely low and no accumulation of nitrite was observed under the simulated low-temperature geothermal conditions without addition of biomass and oxygen.

  15. Ultra-deep blockade of Na+ channels by a quaternary ammonium ion: catalysis by a transition-intermediate state?

    PubMed Central

    Gingrich, K J; Beardsley, D; Yue, D T

    1993-01-01

    1. Individual Na+ channels from isolated guinea-pig ventricular heart cells were studied using the patch-clamp technique. To localize the selectivity region of the channels we investigated their blockade by a permanently charged quaternary ammonium ion (QX-314, 2-(triethylamino)-N-(2,6-dimethylphenyl)acetamide, 0-5 mM) that was applied to the cytoplasmic side of the channel. 2. Resolution of individual blocking events was enhanced by covalent removal of fast inactivation following brief internal exposure to the enzyme papain. The improved resolution reveals the existence of two distinct modalities of blockade: reduction of unitary current, and millisecond interruptions of current. 3. Both modes of internal block could be potentiated by lowering external Na+ concentration. This finding argues that the two corresponding sites of interaction are both located within the channel pore. 4. Analysis of the voltage dependence of block placed both binding sites deep within the pore, at 70% of the electric field from the cytoplasmic entrance. Combined with recent studies localizing block by external Cd2+, the present results argue that the selectivity region of Na+ channels is quite narrow (spanning about 10% of the electric field), and located near the external side of the channel. 5. The manner in which the two blocking processes interact, along with the physical proximity of their binding sites, leads us to propose that the block configuration responsible for the reduction in unitary current serves as a transition intermediate that catalyses formation of the discrete-block complex. PMID:8120809

  16. Quaternary Ammonium Salts Immobilized on Silica Gel: Exchange Properties and Application as Potentiometric Sensor for Perchlorate Ions.

    PubMed

    de Campos, Elvio A.; da Silva Alfaya, Antonio A.; Ferrari, Rosilene T.; Costa, Creusa Maieru M.

    2001-08-01

    Ammonium chlorides immobilized on silica gel, SA(+)/Cl(-) and SE(+)/Cl(-), were obtained from silica previously modified with 3-aminopropyltriethoxysilane and N-[3-(trimethoxysilyl)-propyl]ethylenediamine, respectively. Both materials showed potential use as an anion exchanger: they are thermically stable (up to 413 K), achieve equilibrium rapidly in the presence of suitable exchanger ions, and are easily recovered. The exchange capacities observed for SA(+)/Cl(-) and SE(+)/Cl(-) are 0.70 and 1.19 mmol Cl(-) g(-1), respectively. Through the exchange isotherms and competitive Cl(-)-X(-) exchange (X(-)=F(-), Br(-), I(-), N(3)(-), NO(3)(-), SCN(-), ClO(4)(-)) it was observed that: (i) SE(+)/Cl(-) exchanges the counterion Cl(-) more easily than SA(+)/Cl(-); (ii) SA(+)/Cl(-) presents higher selectivity than SE(+)/Cl(-); and (iii) SA(+)/Cl(-) presents high affinity for ClO(4)(-). Because of these two latter properties presented by the SA(+)/Cl(-), the derivative SA(+)/ClO(4)(-) was used as a potentiometric sensor for this anion, prepared from the supported material on a mixture of graphite powder with epoxy resin. The electrode showed a nernstian behavior and a limit of response of 0.13 mmol L(-1). Potentiometric selectivity coefficients, K(pot)(A, B), were obtained for some interfering anions, and the following interference order was observed: F(-) > SCN(-) > NO(3)(-) > Br(-) > Cl(-) > CH(3)COO(-). The electrode showed fast and stable responses and was useful for approximately 200 measures. Copyright 2001 Academic Press.

  17. Adsorption and transformation of ammonium ion in a loose-pore geothermal reservoir: Batch and column experiments

    NASA Astrophysics Data System (ADS)

    Zhao, Li; Li, Yanli; Wang, Shidong; Wang, Xinyi; Meng, Hongqi; Luo, Shaohe

    2016-09-01

    Adsorption kinetics and transformation process of ammonium ion (NH4+) were investigated to advance the understanding of N cycle in a low-temperature loose-pore geothermal reservoir. Firstly, batch experiments were performed in order to determine the sorption capacity and the kinetic mechanism of NH4+ onto a loose-pore geothermal reservoir matrix. Then column experiments were carried out at temperatures from 20 °C to 60 °C in order to determine the transport parameters and transformation mechanism of NH4+ in the studied matrix. The results showed that the adsorption process of NH4+ onto the porous media well followed the pseudo-second-order model. No obvious variation of hydrodynamic dispersion coefficient (D) and retardation factor (R) was observed at different transport distances at a Darcy's flux of 2.27 cm/h, at which nitrification could be neglected. The simulated D obtained by the CDE model in CXTFIT2.1 increased with temperature while R decreased with temperature, indicating that the adsorption capacity of NH4+ onto the matrix decreased with the increasing of temperature. When the Darcy's flux was decreased to 0.014 cm/h, only a little part of NH4+ could be transformed to nitrate, suggesting that low density of nitrifiers existed in the simulated loose-pore geothermal reservoir. Although nitrification rate increased with temperature in the range of 20 °C to 60 °C, it was extremely low and no accumulation of nitrite was observed under the simulated low-temperature geothermal conditions without addition of biomass and oxygen.

  18. Effects of three kinds of organic acids on phosphorus recovery by magnesium ammonium phosphate (MAP) crystallization from synthetic swine wastewater.

    PubMed

    Song, Yonghui; Dai, Yunrong; Hu, Qiong; Yu, Xiaohua; Qian, Feng

    2014-04-01

    P recovery from swine wastewater has become a great concern as a result of the high demand for P resources and its potential eutrophication effects on water ecosystems. The method of magnesium ammonium phosphate (MAP) crystallization was used to recover P from simulated swine wastewater, and the effects of three organic acids (citric acid, succinic acid and acetic acid) on P removal efficiency and rate at different pH values were investigated. The results indicated that the P removal efficiency was worst affected by citric acid in the optimal pH range of 9.0-10.5, followed by succinic acid and acetic acid, and the influencing extent of organic acids decreased with the increasing pH value. Due to the complexation between organic acid and Mg(2+)/NH4(+), all of three organic acids could inhibit the P removal rate at the beginning of the reaction, which showed positive correlation between the inhibition effects and the concentration of organic acids. The high concentration of citric acid could completely suppress the MAP crystallization reaction. Moreover, citric acid and succinic acid brought obvious effects on the morphology of the crystallized products. The experimental results also demonstrated that MAP crystals could be obtained in the presence of different kinds and concentrations of organic acids.

  19. Limitation of sludge biotic index application for control of a wastewater treatment plant working with shock organic and ammonium loadings.

    PubMed

    Drzewicki, Adam; Kulikowska, Dorota

    2011-11-01

    This study aimed to determine the relationship between activated sludge microfauna, the sludge biotic index (SBI) and the effluent quality of a full-scale municipal wastewater treatment plant (WWTP) working with shock organic and ammonium loadings caused by periodic wastewater delivery from septic tanks. Irrespective of high/low effluent quality in terms of COD, BOD5, ammonium and suspended solids, high SBI values (8-10), which correspond to the first quality class of sludge, were observed. High SBI values were connected with abundant taxonomic composition and the domination of crawling ciliates with shelled amoebae and attached ciliates. High SBI values, even at a low effluent quality, limit the usefulness of the index for monitoring the status of an activated sludge system and the effluent quality in municipal WWTP-treated wastewater from septic tanks. It was shown that a more sensitive indicator of effluent quality was a change in the abundance of attached ciliates with a narrow peristome (Vorticella infusionum and Opercularia coarctata), small flagellates and crawling ciliates (Acineria uncinata) feeding on flagellates.

  20. Radionuclide Leaching from Organic Ion Exchange Resin

    SciTech Connect

    Delegard, C.H.; Rinehart, D.E.

    1999-04-02

    Laboratory tests were performed to examine the efficacy of leach treatments for decontaminating organic ion exchange resins (OIER), which have been found in a number of samples retrieved from K East Basin sludge. Based on process records, the OIER found in the K Basins is a mixed-bet strong acid/strong base material marketed as Purolite{trademark} NRW-037. Radionuclides sorbed or associated with the OIER can restrict its disposal to the Environmental Restoration Disposal Facility (ERDF). The need for testing to support development of a treatment process for K Basin sludge has been described in Section 4.2 of ''Testing Strategy to Support the Development of K Basins Sludge Treatment Process'' (Flament 1998). To help understand the effects of anticipated OIER elutriation and washing, tests were performed with well-rinsed OIER material from K East Basin floor sludge (sample H-08 BEAD G) and with well-rinsed OIER having approximately 5% added K East canister composite sludge (sample KECOMP). The rinsed resin-bearing material also contained the inorganic ion exchanger Zeolon-900{trademark}, a zeolite primarily composed of the mineral mordenite. The zeolite was estimated to comprise 27 weight percent of the dry H-08 BEAD G material.

  1. Effective ammonium removal by anaerobic oxidation in microbial fuel cells.

    PubMed

    Jadhav, Dipak A; Ghangrekar, Makarand M

    2015-01-01

    Dual-chamber microbial fuel cells (MFCs), made of clayware cylinder, were operated at different chemical oxygen demands: ammonium-nitrogen (COD:NH4+) ratio (1:1, 10:1 and 5:1) under batch mode for simultaneous removal of ammonia and organic matter from wastewater. Ammonium-N removal efficiencies of 63-32.66% were obtained for COD:NH4+ ratio of 1:10, respectively. Average COD removal efficiencies demonstrated by these MFCs were about 88%; indicating effective use of MFCs for treatment of wastewater containing organic matter and high ammonia concentration. MFCs operated with COD:NH4+ ratio of 10:1 produced highest volumetric power density of 752.88 mW/m3. The ammonium-N removal slightly increased when microbes were exposed to only ammonium as a source of electron when organic source was not supplemented. When this MFC was operated with imposed potential on cathode and without aeration in the cathode chamber, oxidation of ammonium ions at a faster rate confirmed anaerobic oxidation. During the non-turnover condition of cyclic voltammetry, MFC operated with COD:NH4+ ratio of 10:1 gave higher oxidative and reductive currents than MFC operated with COD:NH4+ ratio of 1:1 due to higher redox species. Successful application of such an anammox process for ammonium oxidation in MFCs will be useful for treatment of wastewater containing higher ammonium concentration and harvesting energy in the form of electricity.

  2. Analysis of Ammonium Nitrate/Urea Nitrate with Crown Ethers and Sugars as Modifiers by Electrospray Ionization-Mass Spectrometry and Ion Mobility Spectrometry.

    PubMed

    Tsai, Chia-Wei; Midey, Anthony; Wu, Ching; Yost, Richard A

    2016-10-04

    Ammonium nitrate (AN) and urea nitrate (UN) are commonly used materials in improvised explosive devices (IEDs). Detection by mass spectrometry (MS) and/or ion mobility spectrometry (IMS) is traditionally difficult. The major challenges of detecting these species arise from their ionic nature and their low mass (for MS detection) and size (for IMS detection). Although AN and UN both produce characteristic higher mass (and size) cluster ions when ionized by electrospray ionization (ESI), detection of AN/UN using cluster ions poses difficulty at trace levels because their formation is concentration-dependent. The addition of modifiers to the ESI process is demonstrated here to overcome some of these challenges for the detection of AN and UN using MS and/or IMS.

  3. Facilitated ion transfer of protonated primary organic amines studied by square wave voltammetry and chronoamperometry.

    PubMed

    Torralba, E; Ortuño, J A; Molina, A; Serna, C; Karimian, F

    2014-05-15

    The transfer of the protonated forms of heptylamine, octylamine, decylamine, procaine and procainamide facilitated by dibenzo-18-crown-6 from water to a solvent polymeric membrane has been investigated by using cyclic square wave voltammetry. The experimental voltammograms obtained are in good agreement with theoretical predictions. The values of the standard ion transfer potential, complexation constant and diffusion coefficient in water have been obtained from these experiments, and have been used to draw some conclusions about the lipophilicity of these species and the relative stability of the organic ammonium complexes with dibenzo-18-crown-6. The results have been compared with those provided by linear sweep voltammetry. Calibration graphs were obtained with both techniques. An interesting chronoamperometric method for the determination of the diffusion coefficient of the target ion in the membrane has been developed and applied to all these protonated amines.

  4. In-situ leaching of south Texas uranium ores--part 2: Oxidative removal of adsorbed ammonium ions with sodium hypochlorite

    SciTech Connect

    Paul, J.M.; Fletcher, A.; Johnson, W.F.; Venuto, P.B.

    1983-04-01

    This paper reports a laboratory study of the oxidative destruction by sodium hypochlorite (NaOCl) of ammonium ions adsorbed on relatively reduced south Texas uranium ore. Included are an assessment of reaction stoichiometry, determination of some major reaction pathways and side reactions, and identification of several intermediates. Adsorbed ammonium ions were completely removed by 0.5% NaOCl, with the concentration of NH/sub 3/ in the effluent falling to a very low value after 10 to 15 PV NaOCl oxidant. A small fraction (5 to 10%) of NaOCl was utilized in reacting with NH/sub 3/. After the NH/sub 3/ was nearly depleted, mono-, di-, and trichloramines, the expected intermediates in NaOCl oxidation of NH/sub 3/, were observed. Chloramine decomposition studies showed that all three decomposed completely within 12 days. Since the ore was relatively highly reducing, the major part of the NaOCl was, not unexpectedly, consumed in side reactions. Substantial quantities of sulfate, reflecting oxidation of sulfide minerals such as pyrite, were formed, large amounts of uranium were leached out, and substantial amounts of calcium and magnesium ions were also produced during the presaturation with NH/sub 4/HCO/sub 3/ preceding the oxidation stage.

  5. Indirect atomic absorption spectrometric determination of pindolol, propranolol and levamisole hydrochlorides based on formation of ion-associates with ammonium reineckate and sodium cobaltinitrite.

    PubMed

    Khalil, S; Borham, N

    2000-03-01

    A new simple, accurate, precise and sensitive indirect method for the determination of pindolol HCl (1), propranolol HCl (2) and levamisole HCl (3) using atomic absorption spectrometry has been developed. The method is based on precipitation of the ion-associates formed from the reaction of (1), (2) or (3) with ammonium reineckate and/or sodium cobaltinitrite. The solubility of the solid complexes at the optimum conditions of pH and ionic strength values have been studied. Saturated solutions of each ion-associate were prepared under the optimum conditions and the metal ion content in the supernatant was determined. The method has been used for the determination of 1.14-17.07, 1.18-17.75 and 1.08-16.24 microg/ml of (1), (2) and (3), respectively, using ammonium reineckate, and 1.71-25.60, 1.77-26.62 and 1.62-24.36 microg/ml of (1), (2) and (3), respectively, using sodium cobaltinitrite. The method developed was applied for analysis of bulk drugs and some of their pharmaceutical preparations.

  6. In-situ leaching of south Texas uranium ores--part 2: oxidative removal of adsorbed ammonium ions with sodium hypochlorite

    SciTech Connect

    Paul, J.M.; Fletcher, A.; Johnson, W.F.; Venuto, P.B.

    1983-04-01

    This paper reports a laboratory study of the oxidative destruction by sodium hypochlorite (NaOCl) of ammonium ions adsorbed on relatively reduced south Texas uranium ore. Included are an assessment of reaction stoichiometry, determination of some major reaction pathways and side reactions, and identification of several intermediates. Adsorbed ammonium ions were completely removed by 0.5% NaOCl, with the concentration of NH/sub 3/ in the effluent falling to a very low value after 10 to 15 PV NaOCl oxidant. A small fraction (5 to 10%) of NaOCl was utilized in reacting with NH/sub 3/. After the NH/sub 3/ was nearly depleted, mono-, di-, and trichloramines, the expected intermediates in NaOCl oxidation of NH/sub 3/, were observed. Chloramine decomposition studies showed that all three decomposed completely within 12 days. Since the ore was relatively highly reducing, the major part of the NaOCl was, not unexpectedly, consumed in side reactions. Substantial quantities of sulfate, reflecting oxidation of sulfide minerals such as pyrite, were formed, large amounts of uranium were leached out, and substantial amounts of calcium and magnesium ions were also produced during the presaturation with NH/sub 4/HCO/sub 3/ preceding the oxidation stage.

  7. Interaction between Low Energy Ions and the Complicated Organism

    NASA Astrophysics Data System (ADS)

    Yu, Zeng-liang

    1999-12-01

    Low energy ions exist widely in natural world, but people pay a little attention on the interaction between low energy ions and matter, it is even more out of the question of studying on the relation of low energy ions and the complicated organism. The discovery of bioeffect induced by ion implantation has, however, opened a new branch in the field of ion beam application in life sciences. This paper reports recent advances in research on the role of low energy ions in chemical synthesis of the biomolecules and application in genetic modification.

  8. Influence of organic carbon and nitrate loading on partitioning between dissimilatory nitrate reduction to ammonium (DNRA) and N2 production

    NASA Astrophysics Data System (ADS)

    Hardison, Amber K.; Algar, Christopher K.; Giblin, Anne E.; Rich, Jeremy J.

    2015-09-01

    Biologically available nitrogen is removed from ecosystems through the microbial processes of anaerobic ammonium oxidation (anammox) or denitrification, while dissimilatory nitrate reduction to ammonium (DNRA) retains it. A mechanistic understanding of controls on partitioning among these pathways is currently lacking. The objective of this study was to conduct a manipulative experiment to determine the influence of organic C and NO3- loading on partitioning. Sediment was collected from a location on the southern New England shelf (78 m water depth) and sieved. Half of the sediment was mixed with freeze-dried phytoplankton and the other half was not. Sediment was then spread into 1.5 mm, "thin discs" closed at the bottom and placed in large aquarium tanks with filtered, N2/CO2 sparged seawater to maintain O2 limited conditions. Half of the discs received high NO3- loading, while the other half received low NO3- loading, resulting in a multifactorial design with four treatments: no C addition, low NO3- (-C-N); C addition, low NO3- (+C-N); no C addition, high NO3- (-C+N); and C addition, high NO3- (+C+N). Sediment discs were incubated in the tanks for 7 weeks, during which time inorganic N (NH4+, NO3-, and NO2-) was monitored, and sediment discs were periodically removed from the tanks to conduct 15N isotope labeling experiments in vials to measure potential rates of anammox, denitrification, and DNRA. Temporal dynamics of inorganic N concentrations in the tanks were indicative of anoxic N metabolism, with strong response of the build up or consumption of the intermediate NO2-, depending on treatments. Vial incubation experiments with added 15NO2- + 14NH4+ indicated significant denitrification and DNRA activity in sediment thin discs, but incubations with added 15NH4+ + 14NO2- indicated anammox was not at all significant. Inorganic N concentrations in the tanks were fit to a reactive transport model assuming different N transformations. Organic C decomposition rates

  9. The ammonium ion in a silicate under compression: infrared spectroscopy and powder X-ray diffraction of NH4AlSi3O8—buddingtonite to 30 GPa

    NASA Astrophysics Data System (ADS)

    E. Vennari, Cara; O'Bannon, Earl F.; Williams, Quentin

    2017-02-01

    The behavior of the ammoniated feldspar buddingtonite, NH4AlSi3O8, has been studied using infrared (IR) spectroscopy up to 30 GPa and using synchrotron powder X-ray diffraction to 10 GPa at room temperature. We examine the bonding of the ammonium ion under pressure and in particular whether hydrogen bonding is enhanced by compaction, as well as probe how the ammonium ion affects the elasticity and behavior of the aluminosilicate framework at pressure. Powder diffraction data yield a bulk modulus of 49 GPa for a pressure derivative of 4, implying that the ammonium ion substitution may induce a modest softening of the feldspar lattice relative to the potassium ion. Under compression, the N-H vibrations are remarkably insensitive to pressure throughout the pressure range of these experiments. However, the vibrations of the aluminosilicate framework of buddingtonite undergo changes in their slope at 13 GPa, implying that a change in compressional mechanism occurs near this pressure, but the vibrational modes of the ammonium molecule show little response to this change. These results show that (1) there is little, if any, enhancement of hydrogen bonding between the ammonium ion and the oxygen ions of the silica and aluminum tetrahedral framework under pressure, as manifested by the slight (and mostly positive) shifts in the N-H stretching vibrations of the ammonium ion; (2) ordering of the ammonium ion is not observed under compression, as no changes in peak width or in the general appearance of the spectra are observed under compression; and (3) structural changes induced by pressure in the aluminosilicate framework do not produce significant changes in the bonding of the ammonium ion. Hence, it appears that the ammonium ion interacts minimally with its surrounding lattice, even at high pressures: Its behavior is compatible with it being, aside from Coulombic attraction to the oxygen-dominated matrix, a largely non-interactive guest molecule within the silicate

  10. Novel Ion-Exchange Coagulants Remove More Low Molecular Weight Organics than Traditional Coagulants.

    PubMed

    Zhao, Huazhang; Wang, Lei; Hanigan, David; Westerhoff, Paul; Ni, Jinren

    2016-04-05

    Low molecular weight (MW) charged organic matter is poorly removed by conventional coagulants but contributes to disinfection byproduct formation during chlorination of drinking waters. We hypothesized that CIEX, a new Al-based hybrid coagulant with ion-exchange functional groups, would be new mechanistic approach to remove low MW organic matter during coagulation and would perform better than polyaluminum chloride (PACl) or metal-salt based coagulants. We measured coagulation performance using dissolved organic carbon (DOC) in a high hardness surface water. CIEX achieved excellent turbidity removal and removed 20% to 46% more DOC than FeCl3, Al2(SO4)3, or PACl, depending on dose. The improved DOC removal was attributable to better removal of low MW organic matter (<2 kDa). We further studied removal mechanisms in a model water containing a low MW organic acid (salicylic acid (SA)). CIEX achieved high removal of organic acids (>90% of SA) independent of pH, whereas removal by metal salts was lower (<15%) and was strongly pH dependent. CIEX ion-exchange capability is facilitated by its covalently bound quaternary ammonium group, which conventional coagulants lack. Plus, unlike other cationic polymers that react with chloramines to form N-nitrosodimethylamine (NDMA), CIEX has a low molar yield (9.3 × 10(-7) mol NDMA per mol CIEX-N).

  11. PHOTOCHEMICAL MINERALIZATION OF DISSOLVED ORGANIC NITROGEN TO AMMONIUM IN THE BALTIC SEA

    EPA Science Inventory

    Solar radiation-induced photochemistry can be considered as a new source of nutrients when photochemical reactions release bioavailable nitrogen from biologically non-reactive dissolved organic nitrogen (DON). Pretreatments of Baltic Sea waters in the dark indicated that >72% of ...

  12. Cryo-transmission electron microscopy imaging of the morphology of submicrometer aerosol containing organic acids and ammonium sulfate.

    PubMed

    Veghte, Daniel P; Bittner, Danielle Rae; Freedman, Miriam Arak

    2014-03-04

    The effects of aerosol particles on heterogeneous atmospheric chemistry and climate are determined in part by the internal arrangement of compounds within the particles. To characterize the morphology of internally mixed aerosol particles in the accumulation mode size regime, we have used cryo-transmission electron microscopy to investigate the phase separation behavior of dry, submicrometer particles composed of ammonium sulfate mixed with carboxylic acids (adipic, azelaic, citric, glutaric, malonic, pimelic, suberic, and succinic acid). Determining the morphology of dry particles is important for understanding laboratory studies of aerosol optical properties, reactivity, and cloud condensation nucleus activity, results from field instruments where aerosol particles are dried prior to analysis, and atmospheric processes like deposition mode heterogeneous ice nucleation that occur on dried particles. We observe homogeneous morphologies for highly soluble organic compounds. For organic compounds with limited aqueous solubility, partially engulfed structures are observed. At intermediate aqueous solubilities, small particles are homogeneous and larger particles are partially engulfed. Results are compared to previous studies of liquid-liquid phase separation in supermicrometer particles and the impact of these dry particle morphologies on aerosol-climate interactions are discussed.

  13. Main-chain supramolecular polymers based on orthogonal benzo-21-crown-7/secondary ammonium salt and terpyridine/metal ion recognition motifs.

    PubMed

    Tian, Yu-Kui; Wang, Feng

    2014-02-01

    Orthogonal self-assembly of multiple components represents an efficient strategy to afford hierarchical and multifunctional assemblies. Here, we demonstrate the orthogonal recognition behaviors between benzo-21-crown-7/secondary ammonium salt and terpyridine/metal ions (Fe(2+) or Zn(2+) ) recognition motifs. Main-chain supramolecular polymers are subsequently achieved via "one-pot" mixing of the three monomers together (heteroditopic monomer 1, homoditopic secondary ammonium salt monomer 2, and Fe(BF4 )2 •6H2 O or Zn(OTf)2 ), which are confirmed by (1) H NMR, UV-Vis, DOSY, and viscosity measurements. Moreover, different metal ions (Fe(2+) or Zn(2+) ) exert considerable effects on the size of the resulting supramolecular polymers. Integration of two different types of non-covalent interactions renders dynamic and responsive properties for the resulting supramolecular polymers, as triggered by a variety of external stimuli such as temperature, potassium cation, as well as stronger chelating ligands. Therefore, the current work is a prerequisite for the future application of such orthogonal assemblies as intelligent supramolecular materials.

  14. Organic Materials as Electrodes for Li-ion Batteries

    DTIC Science & Technology

    2015-09-04

    technology and research towards finding new materials to improve the performance are underway. Conductive organic polymers have been proposed as...indigo carmine conjugated carbonyl organic dye can be used for storing reversibly, both lithium and sodium ions for rechargeable battery applications ...Final 3. DATES COVERED (From - To) 15 May 2013 – 14 May 2015 4. TITLE AND SUBTITLE Organic materials as Electrodes for Li-ion Batteries

  15. Automated, colorimetric methods for determination of nitrate plus nitrite, nitrite, ammonium and orthophosphate ions in natural water samples

    USGS Publications Warehouse

    Antweiler, Ronald C.; Patton, Charles J.; Taylor, Howard E.

    1996-01-01

    The apparatus and methods used for the automatic, colorimetric determinations of dissolved nutrients (nitrate plus nitrite, nitrite, ammonium and orthophosphate) in natural waters are described. These techniques allow for the determination of nitrate plus nitrite for the concentration range 0.02 to 8 mg/L (milligrams per liter) as N (nitrogen); for nitrite, the range is 0.002 to 1.0 mg/L as N; for ammonium, the range is 0.006 to 2.0 mg/L as N; and for orthophosphate, the range is 0.002 to 1.0 mg/L as P (phosphorus). Data are presented that demonstrate the accuracy, precision and quality control of the methods.

  16. Organic positive ions in aircraft gas-turbine engine exhaust

    NASA Astrophysics Data System (ADS)

    Sorokin, Andrey; Arnold, Frank

    Volatile organic compounds (VOCs) represent a significant fraction of atmospheric aerosol. However the role of organic species emitted by aircraft (as a consequence of the incomplete combustion of fuel in the engine) in nucleation of new volatile particles still remains rather speculative and requires a much more detailed analysis of the underlying mechanisms. Measurements in aircraft exhaust plumes have shown the presence of both different non-methane VOCs (e.g. PartEmis project) and numerous organic cluster ions (MPIK-Heidelberg). However the link between detected organic gas-phase species and measured mass spectrum of cluster ions is uncertain. Unfortunately, up to now there are no models describing the thermodynamics of the formation of primary organic cluster ions in the exhaust of aircraft engines. The aim of this work is to present first results of such a model development. The model includes the block of thermodynamic data based on proton affinities and gas basicities of organic molecules and the block of non-equilibrium kinetics of the cluster ions evolution in the exhaust. The model predicts important features of the measured spectrum of positive ions in the exhaust behind aircraft. It is shown that positive ions emitted by aircraft engines into the atmosphere mostly consist of protonated and hydrated organic cluster ions. The developed model may be explored also in aerosol investigations of the background atmosphere as well as in the analysis of the emission of fine aerosol particles by automobiles.

  17. The synergistic effect of organic silicone quaternary ammonium salt and 5-fluorouracil on hepatocellular carcinoma in vitro and in vivo.

    PubMed

    Wang, Juan-Xia; Zhang, Ling-Yi; Zhang, Jun; Ding, Hui; Wang, Dong-Min; Wang, Zhi-Ping

    2014-09-01

    Hepatocellular carcinoma (HCC) is the third most common type of cancer worldwide, causing over 370,000 deaths per year, with approximately half of them in China. Chemotherapy is the optimal treatment for patients with advanced HCC, although chemoresistance has become a significant obstacle to successful liver cancer surgery. In this paper, we have assessed the characteristics of drugs to explore the effects of individual and combined action of organic silicone quaternary ammonium salt (Jieyoushen) and 5-fluorouracil (5-FU). The results of MTT assays showed that single and combined action of Jieyoushen and 5-FU can inhibit the proliferation of liver carcinoma cell lines in a dose-dependent and time-dependent manner, respectively. Electron microscopy and Hoechst 33342 staining showed characteristic apoptotic bodies in apoptotic cells treated with Jieyoushen and 5-FU. Flow cytometry results indicated that the percentage of cells at G0/G1 phase gradually increased, whereas it gradually decreased during the S phase after treatment. Taken together, these results suggest that the combination of Jieyoushen with 5-FU exerts a synergistic anticancer effect on HCC growth and that targeted therapeutic strategies may improve HCC sensitivity to chemotherapy.

  18. Mass spectrometry. [in organic ion and biorganic chemistry and medicine

    NASA Technical Reports Server (NTRS)

    Burlingame, A. L.; Cox, R. E.; Derrick, P. J.

    1974-01-01

    Review of the present status of mass spectrometry in the light of pertinent recent publications spanning the period from December 1971 to January 1974. Following an initial survey of techniques, instruments, and computer applications, a sharp distinction is made between the chemistry of organic (radical-)ions and analytical applications in biorganic chemistry and medicine. The emphasis is on the chemistry of organic (radical-)ions at the expense of inorganic, organometallic, and surface ion chemistry. Biochemistry and medicine are chosen because of their contemporary importance and because of the stupendous contributions of mass spectroscopy to these fields in the past two years. In the review of gas-phase organic ion chemistry, special attention is given to studies making significant contributions to the understanding of ion chemistry.

  19. A structure-function analysis of ion transport in crustacean gills and excretory organs.

    PubMed

    Freire, Carolina A; Onken, Horst; McNamara, John C

    2008-11-01

    Osmotic and ionic regulation in the Crustacea is mostly accomplished by the multifunctional gills, together with the excretory organs. In addition to their role in gas exchange, the gills constitute organs of active, transepithelial, ion transport, an activity of major importance that underlies many essential physiological functions like osmoregulation, calcium homeostasis, ammonium excretion and extracellular pH regulation. This review focuses on structure-function relationships in crustacean gills and excretory effectors, from the organ to molecular levels of organization. We address the diversity of structural architectures encountered in different crustacean gill types, and in constituent cell types, before examining the physiological mechanisms of Na(+), Cl(-), Ca(2+) and NH(4)(+) transport, and of acid-base equivalents, based on findings obtained over the last two decades employing advanced techniques. The antennal and maxillary glands constitute the principal crustacean excretory organs, which have received less attention in functional studies. We examine the diversity present in antennal and maxillary gland architecture, highlighting the structural similarities between both organ types, and we analyze the functions ascribed to each glandular segment. Emphasis is given to volume and osmoregulatory functions, capacity to produce dilute urine in freshwater crustaceans, and the effect of acclimation salinity on urine volume and composition. The microanatomy and diversity of function ascribed to gills and excretory organs are appraised from an evolutionary perspective, and suggestions made as to future avenues of investigation that may elucidate evolutionary and adaptive trends underpinning the invasion and exploitation of novel habitats.

  20. Tandem mass spectrometric analysis of novel diquaternary ammonium gemini surfactants and their bromide adducts in electrospray-positive ion mode ionization.

    PubMed

    Buse, Joshua; Badea, Ildiko; Verrall, Ronald E; El-Aneed, Anas

    2011-10-01

    Gemini surfactants are cationic lipids which are utilized for both in vitro and in vivo gene delivery. Structurally, they are comprised of two hydrophobic tail regions with polar head termini that are attached to one another through a spacer region. Structural elucidation and characterization of 29 novel diquaternary ammonium gemini surfactant molecules were achieved using a quadrupole time-of-flight mass spectrometer (QqToF-MS) and a quadrupole-hexapole-quadrupole mass spectrometer (QhQ-MS). The tested compounds were categorized into four distinct structural families based upon the composition of the spacer region. Single stage (MS), tandem stage (MS/MS) and quasimulti-stage (quasi MS(3)) mass spectrometric analysis allowed for confirmation of each gemini surfactant's molecular composition and structure through the identification of common and unique product ions. Identification of similarities in the gemini surfactants' fragmentation behaviour resulted in the production of a universal fragmentation pathway that can assist in the future MS/MS analysis of novel quaternary ammonium gemini surfactants, with unique product ions being indicative of specific structural elements. Furthermore, evidence for the association of agemini surfactant with bromine counter ion was confirmed during MS analysis of tested gemini surfactants regardless of their chemical composition; previously, evidence for bromine and gemini surfactant association was only observed with compounds bearing short alkyl spacer regions. MS/MS analysis of the bromine adducts was also confirmatory to the molecular structure.Understanding the ionization and fragmentation behaviour of gemini surfactants, including bromine adducts, will allow for future qualitative and quantitative identification of these novel drug delivery agents within biological samples.

  1. Development of polyatomic ion beam system using liquid organic materials

    NASA Astrophysics Data System (ADS)

    Takaoka, G. H.; Nishida, Y.; Yamamoto, T.; Kawashita, M.

    2005-08-01

    We have developed a new type of polyatomic ion beam system using liquid organic materials such as octane and ethanol, which consists of a capillary type of nozzle, an ionizer, a mass-separator and a substrate holder. Ion current extracted after ionization was 430 μA for octane and 200 μA for ethanol, respectively. The mass-analysis was realized using a compact E × B mass filter, and the mass-analyzed ion beams were transferred toward the substrate. The ion current density at the substrate was a few μA/cm2 for the mass-separated ion species. Interactions of polyatomic ion beams with silicon (Si) surfaces were investigated by utilizing the ellipsometry measurement. It was found that the damaged layer thickness irradiated by the polyatomic ions with a mass number of about 40 was smaller than that by Ar ion irradiation at the same incident energy and ion fluence. The result indicated that the rupture of polyatomic ions occurred upon its impact on the Si surface with an incident energy larger than a few keV. In addition, the chemical modification of Si surfaces such as wettability could be achieved by adjusting the incident energy for the ethanol ions, which included all the fragment ions.

  2. Modeling downward particulate organic nitrogen flux from zooplankton ammonium regeneration in the northern Benguela

    NASA Astrophysics Data System (ADS)

    Fernández-Urruzola, I.; Osma, N.; Gómez, M.; Pollehne, F.; Postel, L.; Packard, T. T.

    2016-12-01

    The vertical fluxes of particulate organic matter play a crucial role in the distribution of nutrients throughout the oceans. Although they have been the focus of intensive research, little effort has been made to explore alternative approaches that quantify the particle export at a high spatial resolution. In this study, we assess the minimum nitrogen flux (FN) required to sustain the heterotrophic metabolism in the water column from ocean depth profiles of zooplankton NH4+ excretion (RNH4+). The reduction of RNH4+ as a function of depth was described by a power law fit, RNH4+ = (RNH4+)m (z /zm)b , whereby the b-value determines the net particulate nitrogen loss with increasing depth. Integrating these excretory functions from the base of the euphotic zone to the ocean bottom, we calculated FN at two stations located over the Namibian outer shelf. Estimates of FN (ranging between 0.52 and 1.14 mmol N m-2 d-1) were compared with the sinking fluxes of particles collected in sediment traps (0.15-1.01 mmol N m-2 d-1) 50 m over the seafloor. We found a reasonable agreement between the two approaches when fast-sinking particles dominated the ecosystem, but the FN was somewhat at odds with the measured gravitational flux during a low-sedimentation regime. Applying our conceptual model to the mesozooplankton RNH4+ we further constructed a section of FN along a cross-shelf transect at 20° S, and estimated the efficiency of the epipelagic ecosystem to retain nutrients. Finally, we address the impact of the active flux driven by the migrant mesozooplankton to the total nitrogen export. Depending on the sedimentation regime, the downward active flux (0.86 mmol N m-2 d-1 at 150 m) accounted for between 50 and 307% of the gravitational flux.

  3. Preparation of porous yttrium oxide microparticles by gelation of ammonium alginate in aqueous solution containing yttrium ions.

    PubMed

    Kawashita, Masakazu; Matsui, Naoko; Li, Zhixia; Miyazaki, Toshiki

    2010-06-01

    Porous Y2O3 microparticles 500 microm in size were obtained, when 1 wt%-ammonium alginate aqueous solution was dropped into 0.5 M-YCl3 aqueous solution by a Pasteur pipette and the resultant gel microparticles were heat-treated at 1100 degrees C. Small pores less than 1 microm were formed in the microparticles by the heat treatment. The bulk density of the heat-treated microparticle was as low as 0.66 g cm(-3). The chemical durability of the heat-treated microparticles in simulated body fluid at pH = 6 and 7 was high enough for clinical application of in situ radiotherapy. Although the size of the microparticles should be decreased to around 25 microm using atomizing device such as spray gun for clinical application, we found that the porous Y2O3 microparticles with high chemical durability and low density can be obtained by utilizing gelation of ammonium alginate in YCl3 aqueous solution in this study.

  4. Ammonium methacrylate

    Integrated Risk Information System (IRIS)

    Ammonium methacrylate ; CASRN 16325 - 47 - 6 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcin

  5. Ammonium sulfamate

    Integrated Risk Information System (IRIS)

    Ammonium sulfamate ; CASRN 7773 - 06 - 0 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogen

  6. Ammonium acetate

    Integrated Risk Information System (IRIS)

    Ammonium acetate ; CASRN 631 - 61 - 8 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic

  7. Acute ammonium dichromate poisoning.

    PubMed

    Meert, K L; Ellis, J; Aronow, R; Perrin, E

    1994-10-01

    We report the ingestion of ammonium dichromate by a child that resulted in multiple-organ-system failure and death. Exchange transfusion and hemodialysis were ineffective in removing significant amounts of chromium or causing sustained clinical improvement. We suggest that immediate, large doses of the reducing agent ascorbic acid would allow effective reduction of hexavalent chromium with less cellular toxicity.

  8. Amphiphilic organic ion pairs in solution: a theoretical study.

    PubMed

    Pradines, Vincent; Poteau, Romuald; Pimienta, Veronique

    2007-07-16

    The macroscopic manifestation of hydrophobic interactions for amphiphilic organic ion pairs (tetraalkylammonium-anion) has been shown experimentally by measuring their association constants and their affinity with the organic phase. Beyond a certain size, there is a direct relation between association constants and chain lengths in tetraalkylammonium ions. We propose to cast a bridge between these results and geometrical properties considered at the level of a single ion pair by means of quantum chemistry calculations performed on model systems: trimethylalkylammonium-pentyl sulfate instead of tetraalkylammonium-dodecyl sulfate. Two limiting cases are considered: head-to-head configurations, which yield an optimal electrostatic interaction between polar heads, and parallel configurations with a balance between electrostatic and hydrophobic interactions. All properties (geometries, complexation energies, and atomic charges) were obtained at the MP2 level of calculation, with water described by a continuum model (CPCM). Dispersion forces link hydrocarbon chains of tetraalkylammonium ions and pentyl sulfate, thus yielding (for the largest ion pairs) parallel configurations favored with respect to head-to-head geometries by solute-solvent electrostatic interactions. Given the small experimental association energies, we probe the accuracy limit of the MP2 and CPCM methods. However, clear trends are obtained as a function of chain length, which agree with the experimental observations. The calculated monotonic stabilization of ion pairs when the hydrocarbon chain increases in length is discussed in terms of electrostatic interactions (between ions and between ion pairs and water), dispersion forces, and cavitation energies.

  9. Closed-state inactivation involving an internal gate in Kv4.1 channels modulates pore blockade by intracellular quaternary ammonium ions.

    PubMed

    Fineberg, Jeffrey D; Szanto, Tibor G; Panyi, Gyorgy; Covarrubias, Manuel

    2016-08-09

    Voltage-gated K(+) (Kv) channel activation depends on interactions between voltage sensors and an intracellular activation gate that controls access to a central pore cavity. Here, we hypothesize that this gate is additionally responsible for closed-state inactivation (CSI) in Kv4.x channels. These Kv channels undergo CSI by a mechanism that is still poorly understood. To test the hypothesis, we deduced the state of the Kv4.1 channel intracellular gate by exploiting the trap-door paradigm of pore blockade by internally applied quaternary ammonium (QA) ions exhibiting slow blocking kinetics and high-affinity for a blocking site. We found that inactivation gating seemingly traps benzyl-tributylammonium (bTBuA) when it enters the central pore cavity in the open state. However, bTBuA fails to block inactivated Kv4.1 channels, suggesting gated access involving an internal gate. In contrast, bTBuA blockade of a Shaker Kv channel that undergoes open-state P/C-type inactivation exhibits fast onset and recovery inconsistent with bTBuA trapping. Furthermore, the inactivated Shaker Kv channel is readily blocked by bTBuA. We conclude that Kv4.1 closed-state inactivation modulates pore blockade by QA ions in a manner that depends on the state of the internal activation gate.

  10. Closed-state inactivation involving an internal gate in Kv4.1 channels modulates pore blockade by intracellular quaternary ammonium ions

    PubMed Central

    Fineberg, Jeffrey D.; Szanto, Tibor G.; Panyi, Gyorgy; Covarrubias, Manuel

    2016-01-01

    Voltage-gated K+ (Kv) channel activation depends on interactions between voltage sensors and an intracellular activation gate that controls access to a central pore cavity. Here, we hypothesize that this gate is additionally responsible for closed-state inactivation (CSI) in Kv4.x channels. These Kv channels undergo CSI by a mechanism that is still poorly understood. To test the hypothesis, we deduced the state of the Kv4.1 channel intracellular gate by exploiting the trap-door paradigm of pore blockade by internally applied quaternary ammonium (QA) ions exhibiting slow blocking kinetics and high-affinity for a blocking site. We found that inactivation gating seemingly traps benzyl-tributylammonium (bTBuA) when it enters the central pore cavity in the open state. However, bTBuA fails to block inactivated Kv4.1 channels, suggesting gated access involving an internal gate. In contrast, bTBuA blockade of a Shaker Kv channel that undergoes open-state P/C-type inactivation exhibits fast onset and recovery inconsistent with bTBuA trapping. Furthermore, the inactivated Shaker Kv channel is readily blocked by bTBuA. We conclude that Kv4.1 closed-state inactivation modulates pore blockade by QA ions in a manner that depends on the state of the internal activation gate. PMID:27502553

  11. Ion distribution in quaternary-ammonium-functionalized aromatic polymers: effects on the ionic clustering and conductivity of anion-exchange membranes.

    PubMed

    Weiber, E Annika; Jannasch, Patric

    2014-09-01

    A series of copoly(arylene ether sulfone)s that have precisely two, three, or four quaternary ammonium (QA) groups clustered directly on single phenylene rings along the backbone are studied as anion-exchange membranes. The copolymers are synthesized by condensation polymerizations that involve either di-, tri-, or tetramethylhydroquinone followed by virtually complete benzylic bromination using N-bromosuccinimide and quaternization with trimethylamine. This synthetic strategy allows excellent control and systematic variation of the local density and distribution of QA groups along the backbone. Small-angle X-ray scattering of these copolymers shows extensive ionic clustering, promoted by an increasing density of QA on the single phenylene rings. At an ion-exchange capacity (IEC) of 2.1 meq g(-1), the water uptake decreases with the increasing local density of QA groups. Moreover, at moderate IECs at 20 °C, the Br(-) conductivity of the densely functionalized copolymers is higher than a corresponding randomly functionalized polymer, despite the significantly higher water uptake of the latter. Thus, the location of multiple cations on single aromatic rings in the polymers facilitates the formation of a distinct percolating hydrophilic phase domain with a high ionic concentration to promote efficient anion transport, despite probable limitations by reduced ion dissociation. These findings imply a viable strategy to improve the performance of alkaline membrane fuel cells.

  12. The multimerization state of retroviral RNA is modulated by ammonium ions and affects HIV-1 full-length cDNA synthesis in vitro.

    PubMed Central

    Weiss, S; Häusl, G; Famulok, M; König, B

    1993-01-01

    Genomic human immunodeficiency virus type 1 (HIV-1) RNA fragments containing the dimer linkage structure (DLS) can be dimerized and multimerized in the presence of NH4+ and in the absence of any other cation and any viral or cellular protein. This effect strongly supports the notion that dimerization and multimerization of genomic RNA occurs via purine-quartet formation in quadruple helical RNA structures. The efficiency of RNA dimerization and multimerization in the presence of ammonium ions is about 400 fold increased as compared to alkali metal ions such as potassium. Dimerized retroviral RNA representing a pseudodiploid genome could account for genetic recombination within the virion and during reverse transcription. Application of a novel South-Northern-Blotting procedure with biotinylated RNA and digoxigenin-labelled cDNA in vitro reveals that efficient human- and bovine tRNA(Lys3) primed full-length cDNA-synthesis only takes place with a predominantly monomerized RNA template. Dimerization and multimerization of the RNA significantly reduces full-length cDNA-synthesis. This suggests that monomerization of the dimerized RNA, effected by deionization in vitro, is essential for efficient retroviral reverse transcription in vivo. Images PMID:8177734

  13. Controlling epileptiform activity with organic electronic ion pumps.

    PubMed

    Williamson, Adam; Rivnay, Jonathan; Kergoat, Loïg; Jonsson, Amanda; Inal, Sahika; Uguz, Ilke; Ferro, Marc; Ivanov, Anton; Sjöström, Theresia Arbring; Simon, Daniel T; Berggren, Magnus; Malliaras, George G; Bernard, Christophe

    2015-05-27

    In treating epilepsy, the ideal solution is to act at a seizure's onset, but only in the affected regions of the brain. Here, an organic electronic ion pump is demonstrated, which directly delivers on-demand pure molecules to specific brain regions. State-of-the-art organic devices and classical pharmacology are combined to control pathological activity in vitro, and the results are verified with electrophysiological recordings.

  14. Separation of organic ion exchange resins from sludge -- engineering study

    SciTech Connect

    Duncan, J.B.

    1998-08-25

    This engineering study evaluates the use of physical separation technologies to separate organic ion exchange resin from KE Basin sludge prior to nitric acid dissolution. This separation is necessitate to prevent nitration of the organics in the acid dissolver. The technologies under consideration are: screening, sedimentation, elutriation. The recommended approach is to first screen the Sludge and resin 300 microns then subject the 300 microns plus material to elutriation.

  15. A smog chamber study coupling a photoionization aerosol electron/ion spectrometer to VUV synchrotron radiation: organic and inorganic-organic mixed aerosol analysis

    NASA Astrophysics Data System (ADS)

    Baeza-Romero, María Teresa; Gaie-Levrel, Francois; Mahjoub, Ahmed; López-Arza, Vicente; Garcia, Gustavo A.; Nahon, Laurent

    2016-07-01

    A reaction chamber was coupled to a photoionization aerosol time-of-flight mass spectrometer based on an electron/ion coincidence scheme and applied for on-line analysis of organic and inorganic-organic mixed aerosols using synchrotron tunable vacuum ultraviolet (VUV) photons as the ionization source. In this proof of principle study, both aerosol and gas phase were detected simultaneously but could be differentiated. Present results and perspectives for improvement for this set-up are shown in the study of ozonolysis ([O3] = 0.13-3 ppm) of α-pinene (2-3 ppm), and the uptake of glyoxal upon ammonium sulphate. In this work the ozone concentration was monitored in real time, together with the particle size distributions and chemical composition, the latter taking advantage of the coincidence spectrometer and the tuneability of the synchrotron radiation as a soft VUV ionization source.

  16. Ageing dynamics of ion bombardment induced self-organization processes

    PubMed Central

    Bikondoa, Oier; Carbone, Dina; Chamard, Virginie; Metzger, Till Hartmut

    2013-01-01

    Instabilities caused during the erosion of a surface by an ion beam can lead to the formation of self-organized patterns of nanostructures. Understanding the self-organization process requires not only the in-situ characterization of ensemble averaged properties but also probing the dynamics. This can be done with the use of coherent X-rays and analyzing the temporal correlations of the scattered intensity. Here, we show that the dynamics of a semiconductor surface nanopatterned by normal incidence ion beam sputtering are age-dependent and slow down with sputtering time. This work provides a novel insight into the erosion dynamics and opens new perspectives for the understanding of self-organization mechanisms. PMID:23685386

  17. Heterogeneous photocatalytic reduction of Cr(VI) in UV-irradiated titania suspensions: Effect of protons, ammonium ions, and other interfacial aspects

    SciTech Connect

    Chenthamarakshan, C.R.; Rajeshwar, K.; Wolfrum, E.J.

    2000-03-21

    Heterogeneous photocatalytic reactions in UV-irradiated TiO{sub 2} suspensions are comprised of two conjugate reaction pathways involving the photogenerated electrons and holes, respectively. The role of the hole reaction pathway in the dynamics of the photocatalytic reduction of Cr(VI) is a major focus of this study. It is shown that proton supply plays a crucial role in this reduction reaction. Thus, the Cr(VI) photoreduction kinetics switch from first order to zero order as the proton concentration is systematically increased in the aqueous suspensions. Ammonium ions are also shown to exert a dramatic accelerating influence on Cr(VI) reduction in media of initial pH6. This new observation is rationalized by considering that these species act as hole scavengers. The consequent improvement in quantum yield combines with the facile proton generation upon NH{sub 4}{sup +} photooxidation, to result in the observed rate enhancement. Other interfacial aspects (i.e. adsorption) are also discussed.

  18. Influence of pH and diluent on the ion-pair solvent extraction of aromatic carboxylic acids using quaternary ammonium salts

    SciTech Connect

    Kawamura, K.; Takahashi, K.; Okuwaki, A.

    2006-07-01

    The influence of pH and diluent on the ion-pair solvent extraction of benzene polycarboxylic acids have been investigated for the separation of the coal oxidation products, which are formed by the treatment with alkaline solutions at high temperatures. Although the extent of the solvent extraction of benzoic acid (1BE) with a quaternary ammonium reagent (tri-n-octylmethylammonium chloride) into chloroform and benzene did not change at a very acidic and alkaline solutions, those of 1,2-benzenedicarboxylic acid (12BE) and trimellitic acid (124BE) somewhat decreased at very low pH and very high pH. The magnitudes of the equilibrium constants (K{sub ex}) of 1BE using a different diluent decreased in the order benzene {gt} carbontetrachloride {gt} 1,2-dichloroethane {gt} cyclohexane {gt} hexane {gt} chloroform {gt} 1-octanol and those of 12BE decreased in the order benzene {gt} cyclohexane {gt} carbontetrachloride {gt} hexane {gt} 1,2-dichloroethane {gt} chloroform. The inspection of the correlation between the values of K{sub ex} and several parameters of the diluent implies that the magnitude of K{sub ex} can be described by using the dielectric constant and the solubility parameter of diluent.

  19. The mechanism of ion exchange and adsorption coexist on medium-low concentration ammonium-nitrogen removal by ion-exchange resin.

    PubMed

    Yunnen, Chen; Xiaoyan, Luo; Changshi, Xiong; Liming, Liang

    2015-01-01

    In this study, the removal of medium-low concentration ammonium-nitrogen ([Formula: see text]) from waters and wastewaters on D113 resin was investigated with respect to pH, initial [Formula: see text] concentration, temperature and contact time. The equilibrium of [Formula: see text] on D113 resin reached in 20-30 min. The process of [Formula: see text] removal by D113 resin fitted Langmuir isotherm well. The pseudo second-order kinetic and intra-particle diffusion models were used to investigate the kinetic data of [Formula: see text] on D113 resin. The desorption solution can be returned to production after pretreatment. The mechanism of removal of [Formula: see text] by D113 resin was coexistence of adsorption and cation exchange. When the dosage of D113 resin was 5 g L(-1), pH 6, contact 30 min at room temperature, initial [Formula: see text] concentration being 116 mg L(-1) in rare earth metallurgical wastewater was reduced to 13 mg L(-1) after adsorption treatment.

  20. Utilization of steel-making slag for the uptake of ammonium and phosphate ions from aqueous solution.

    PubMed

    Jha, Vinay Kumar; Kameshima, Yoshikazu; Nakajima, Akira; Okada, Kiyoshi

    2008-08-15

    Steel-making slag, a waste by-product of the Steel Industry, constitutes a major disposal problem. In the present study, excellent adsorbent materials for reducing eutrophication in wastewaters have been prepared from this slag. Heated samples of acid-treated slag and mixtures of slag with kaolinite and Al(OH)(3) were examined to determine their uptake capacities for NH(4)(+) and PO(4)(3-) from aqueous solutions. In general, the equilibrium pH of the solution increased in comparison to initial pH with the uptake of target ions, the sample activated slag-Al(OH)(3) showing the smallest change. The highest PO(4)(3-) uptake capacity was obtained with the slag-Al(OH)(3) mixture heated at 900 degrees C whereas the highest uptake of NH(4)(+) was found in the slag-Al(OH)(3) mixture heated at 800 degrees C. The uptake rates for PO(4)(3-) and NH(4)(+) by the slag-Al(OH)(3) mixture heated at 900 degrees C were 2.91 and 0.65 micro mol/(g min), respectively. It was shown that heating slag composites prior to incorporation into wastewater treatment filters resulted in an increased degree of NH(4)(+) and PO(4)(3-) uptake.

  1. Dielectric relaxations in partly deuterated ammonium dichromate

    NASA Astrophysics Data System (ADS)

    Gilchrist, John le G.

    1987-12-01

    Two dielectric relaxations in partly deuterated ammonium dichromate are attributed to reorientations of mixed-isotope ammonium ions. Loss peaks were observed between 20 and 40 K and obey the Arrhenius law with activation energy 1.5 kcal/mol for the stronger relaxation. The dipole moment is of the order of 0.015 D.

  2. Quantitative remote sensing of ammonium minerals, Cedar Mountains, Esmeralda County, Nevada

    NASA Technical Reports Server (NTRS)

    Baugh, William M.; Kruse, Fred A.

    1995-01-01

    Mineral-bound ammonium (NH4+) was discovered by the U.S. Geological Survey in the southern Cedar Mountains of Esmeralda County, Nevada in 1989. At 10 km in length, this site is 100 times larger than any previously known occurrence in volcanic rocks. The ammonium occurs in two hydrothermally altered, crystal-rich rhyolitic tuff units of Oligocene age, and is both structurally and stratigraphically controlled. This research uses Advanced Visible/Infrared Imaging Spectrometer (AVIRIS) data to quantitatively map the mineral-bound ammonium (buddingtonite) concentration in the altered volcanic rocks. Naturally occurring mineral-bound ammonium is fairly rare; however, it has been found to occur in gold-bearing hydrothermal deposits. Because of this association, it is thought that ammonium may be a useful too in exploration for gold and other metal deposits. Mineral-bound ammonium is produced when an ammonium ion (NH4+) replaces the alkali cation site (usually K+) in the crystal structure of silicate minerals such as feldspars, micas and clays. Buddingtonite is an ammonium feldspar. The ammonium originates in buried organic plant matter and is transported to the host rock by hydrothermal fluids. Ammonium alteration does not produce visible changes in the rock, and it is barely detectable with standard x-ray diffraction methods. It is clearly identified, however, by absorption features in short wave-infrared (SWIR) wavelengths (2.0 - 2.5 micrometers). The ammonium absorption features are believed to be caused by N-H vibrational modes and are analogous to hydroxyl (O-H) vibrational modes, only shifted slightly in wavelength. Buddingtonite absorption features in the near- and SWIR lie at 1.56, 2.02 and 2.12 micrometers. The feature at 2.12 micrometer is the strongest of the three and is the only one used in this study. The southern Cedar Mountains are sparsely vegetated and are an ideal site for a remote sensing study.

  3. Linear Ion Trap for the Mars Organic Molecule Analyzer

    NASA Astrophysics Data System (ADS)

    Brinckerhoff, William; Arevalo, Ricardo; Danell, Ryan; van Amerom, Friso; Pinnick, Veronica; Li, Xiang; Hovmand, Lars; Getty, Stephanie; Mahaffy, Paul; Goesmann, Fred; Steininger, Harald

    2014-05-01

    The 2018 ExoMars rover mission includes the Mars Organic Molecule Analyzer (MOMA) investigation. MOMA will examine the chemical composition of samples acquired from depths of up to two meters below the martian surface, where organics may be protected from radiative and oxidative degradation. When combined with the complement of instruments in the rover's Pasteur Payload, MOMA has the potential to reveal the presence of a wide range of organics preserved in a variety of mineralogical environments, and to begin to understand the structural character and potential origin of those compounds. MOMA includes a linear, or 2D, ion trap mass spectrometer (ITMS) that is designed to analyze molecular composition of (i) gas evolved from pyrolyzed powder samples and separated on a gas chromatograph and (ii) ions directly desorbed from solid samples at Mars ambient pressure using a pulsed laser and a fast-valve capillary ion inlet system. This "dual source" approach gives MOMA unprecedented breadth of detection over a wide range of molecular weights and volatilities. Analysis of nonvolatile, higher-molecular weight organics such as carboxylic acids and peptides even in the presence of significant perchlorate concentrations is enabled by the extremely short (~1 ns) pulses of the desorption laser. Use of the ion trap's tandem mass spectrometry mode permits selective focus on key species for isolation and controlled fragmentation, providing structural analysis capabilities. The flight-like engineering test unit (ETU) of the ITMS, now under construction, will be used to verify breadboard performance with high fidelity, while simultaneously supporting the development of analytical scripts and spectral libraries using synthetic and natural Mars analog samples guided by current results from MSL. ETU campaign data will strongly advise the specifics of the calibration applied to the MOMA flight model as well as the science operational procedures during the mission.

  4. [Simultaneous separation of organic acid and organic salts by electrostatic ion chromatography].

    PubMed

    Shen, G J; Yang, R F; Yu, A M

    2001-09-01

    The electrostatic ion chromatographic column was prepared by coating conjugated acid salt micelles on the surface of octadecyl silica stationary phase. Pure water was used as mobile phase, and the conductance detector was connected on-line to electrostatic ion chromatograph. The conditions under which organic acid and organic salts were detected were studied. The mechanism for the above separation is discussed. Sodium benzoate and citric acid in Lichee drink were separated and determined. This method is rapid, simple with little interference and good reproducibility without any pollution since the mobile phase is water. This is an environmental friendly analytical method.

  5. Secondary Organic Aerosol and Brown Carbon Formation in the Sunlit Aqueous Phase: Aldehyde Photooxidation in the Presence of Ammonium Salts and Amines

    NASA Astrophysics Data System (ADS)

    De Haan, D. O.; Galloway, M. M.; Sharp, K. D.; Jiménez, N. G.

    2014-12-01

    The chemistry of water-soluble carbonyl compounds in clouds is now acknowledged as an important source of secondary organic aerosol. These reactive carbonyl compounds are oxidized to carboxylic acids and form oligomers by radical-radical reactions and by "dark reactions" with ammonium salts (AS) and/or amines. The latter class of reactions also produces light-absorbing brown carbon compounds, especially reactions involving methylglyoxal or glyoxal and amines. However, recent work has found that UV light fades the color of glyoxal + AS and methylgyloxal + AS reaction mixtures. We recently studied aldehyde-AS-amine reactions in sunlight and in control vessels at the same temperature to determine the effects of solar radiation on the aqueous-phase production of brown carbon. In sunlight, methylglyoxal reaction mixtures lost their initial color and failed to brown, indicating the photolytic loss of reactants and/or pre-brown intermediates. In many other reactions, brown products are lost to photolysis, reducing the overall browning of solutions exposed to sunlight. In other experiments, hydrogen peroxide was added to generate OH radicals by photolysis. In the presence of OH radicals, some carbonyl compound mixtures (e.g. those containing hydroxyacetone or glycolaldehyde) browned more rapidly when exposed to sunlight. This indicates the existence of uncharacterized photooxidative browning pathways involving aqueous-phase OH radicals, carbonyls, ammonium salts, and/or amine compounds.

  6. Method of uranium reclamation from aqueous systems by reactive ion exchange. [US DOE patent application; anion exchange resin of copolymerized divinyl-benzene and styrene having quarternary ammonium groups and bicarbonate ligands

    DOEpatents

    Maya, L.

    1981-11-05

    A reactive ion exchange method for separation and recovery of values of uranium, neptunium, plutonium, or americium from substantially neutral aqueous systems of said metals comprises contacting said system with an effective amount of a basic anion exchange resin of copolymerized divinyl-benzene and styrene having quarternary ammonium groups and bicarbonate ligands to achieve nearly 100% sorption of said actinyl ion onto said resin and an aqueous system practically free of said actinyl ions. The method is operational over an extensive range of concentrations from about 10/sup -6/ M to 1.0 M actinyl ion and a pH range of about 4 to 7. The method has particulr application to treatment of waste streams from Purex-type nuclear fuel reprocessing facilities and hydrometallurgical processes involving U, Np, P, or Am.

  7. Metal-organic frameworks for lithium ion batteries and supercapacitors

    SciTech Connect

    Ke, Fu-Sheng; Wu, Yu-Shan; Deng, Hexiang

    2015-03-15

    Porous materials have been widely used in batteries and supercapacitors attribute to their large internal surface area (usually 100–1000 m{sup 2} g{sup −1}) and porosity that can favor the electrochemical reaction, interfacial charge transport, and provide short diffusion paths for ions. As a new type of porous crystalline materials, metal-organic frameworks (MOFs) have received huge attention in the past decade due to their unique properties, i.e. huge surface area (up to 7000 m{sup 2} g{sup −1}), high porosity, low density, controllable structure and tunable pore size. A wide range of applications including gas separation, storage, catalysis, and drug delivery benefit from the recent fast development of MOFs. However, their potential in electrochemical energy storage has not been fully revealed. Herein, the present mini review appraises recent and significant development of MOFs and MOF-derived materials for rechargeable lithium ion batteries and supercapacitors, to give a glimpse into these potential applications of MOFs. - Graphical abstract: MOFs with large surface area and high porosity can offer more reaction sites and charge carriers diffusion path. Thus MOFs are used as cathode, anode, electrolyte, matrix and precursor materials for lithium ion battery, and also as electrode and precursor materials for supercapacitors. - Highlights: • MOFs have potential in electrochemical area due to their high porosity and diversity. • We summarized and compared works on MOFs for lithium ion battery and supercapacitor. • We pointed out critical challenges and provided possible solutions for future study.

  8. Barcoded materials based on photoluminescent hybrid system of lanthanide ions-doped metal organic framework and silica via ion exchange.

    PubMed

    Shen, Xiang; Yan, Bing

    2016-04-15

    A multicolored photoluminescent hybrid system based on lanthanide ions-doped metal organic frameworks/silica composite host has potential in display and barcode applications. By controlling the stoichiometry of the lanthanides via cation exchange, proportional various lanthanide ions are successfully introduced into metal organic frameworks, whose emission intensity is correspondingly proportional to its amount. The resulting luminescent barcodes depend on the lanthanide ions ratios and compositions. Subsequently, the lanthanide ions located in the channels of metal organic frameworks are protected from any interaction with the environment after the modification of silica on the surface. The optical and thermal stability of the hybrid materials are improved for technological application.

  9. Vitrification of cesium-contaminated organic ion exchange resin

    SciTech Connect

    Sargent, Jr., Thomas N.

    1994-08-01

    Vitrification has been declared by the Environmental Protection Agency (USEPA) as the Best Demonstrated Available Technology (BDAT) for the permanent disposal of high-level radioactive waste. Savannah River Site currently uses a sodium tetraphenylborate (NaTPB) precipitation process to remove Cs-137 from a wastewater solution created from the processing of nuclear fuel. This process has several disadvantages such as the formation of a benzene waste stream. It has been proposed to replace the precipitation process with an ion exchange process using a new resorcinol-formaldehyde resin developed by Savannah River Technical Center (SRTC). Preliminary tests, however, showed that problems such as crust formation and a reduced final glass wasteform exist when the resin is placed in the melter environment. The newly developed stirred melter could be capable of overcoming these problems. This research explored the operational feasibility of using the stirred tank melter to vitrify an organic ion exchange resin. Preliminary tests included crucible studies to determine the reducing potential of the resin and the extent of oxygen consuming reactions and oxygen transfer tests to approximate the extent of oxygen transfer into the molten glass using an impeller and a combination of the impeller and an external oxygen transfer system. These preliminary studies were used as a basis for the final test which was using the stirred tank melter to vitrify nonradioactive cesium loaded organic ion exchange resin. Results from this test included a cesium mass balance, a characterization of the semi-volatile organic compounds present in the off gas as products of incomplete combustion (PIC), a qualitative analysis of other volatile metals, and observations relating to the effect the resin had on the final redox state of the glass.

  10. Characterization of ammonium retention processes onto cactus leaves fibers using FTIR, EDX and SEM analysis.

    PubMed

    Wahab, Mohamed Ali; Boubakri, Hatem; Jellali, Salah; Jedidi, Naceur

    2012-11-30

    In order to reduce the impact of nitrogen pollution and to increase the agronomic value of plant wastes to be reused as organic fertilizer, we have investigated the removal of ammonium from aqueous solutions onto cactus leave fibers (CLF), and the mechanisms involved in the retention of ammonium at CLF surface. The results showed that ammonium retention onto these fibers occurred for a wide pH (6-10) and temperature ranges (20-60°C) and the biosorption potential of CLF increased with temperature from 1.4 to 2.3 mg g(-1) for initial concentration of 50 mg L(-1). The modeling studies showed that the ammonium biosorption was well described by the pseudo-second-order model, predicting therefore, chemisorption interactions-type at earlier stages and by intraparticle diffusion at later stages. Biosorption is governed by film diffusion process at higher concentrations and by particle diffusion process at higher temperatures. The surface of CLF determined by SEM revealed the presence of cracks and cavities which may allow the intraparticle diffusion and the ion exchange processes. Moreover, FTIR and EDX analysis before and after ammonium retention showed that the main mechanisms involved in the removal of ammonium were the ionic exchange by calcium ions as well as H(+) and the complexation with carboxylic, alcoholic and phenolic groups.

  11. Influence of the Salting-out Effect of Ammonium Sulfate on the Gas-Particle Partitioning of Organic Compounds in the Atmosphere

    NASA Astrophysics Data System (ADS)

    Wang, C.; Lei, Y. D.; Endo, S.; Wania, F.

    2014-12-01

    As one of the major salts in the atmosphere, ammonium sulfate ((NH4)2SO4) influences significantly the partitioning of organic compounds into atmospheric aqueous phases. This salting out effect has important implications regarding the reactivity, transport and fate of organic compounds in atmospheric waters, particularly in aerosol particles because of the relatively large amount of salts present. However, very few studies have quantified the salting out effect of (NH4)2SO4. For the first time, we measured salting-out coefficients (or Setschenow constants) (KS [M-1]) for a large and diverse group of organic compounds in (NH4)2SO4 solutions at a wide range of salt concentrations, providing a reliable database for model development. KS values for (NH4)2SO4 are correlated with and always higher than KS for sodium chloride (NaCl), suggesting a higher salting-out effect of (NH4)2SO4. Three modeling approaches: a poly-parameter linear free energy relationship (pp-LFER), the quantum-chemical COSMOtherm software and the group contribution method AIMOFAC, were calibrated and evaluated in terms of their capability to predict KS. Relative merits of the prediction methods were identified. These models can be applied to estimate Setschenow constants for atmospherically relevant compounds involved in secondary organic aerosol formation based on chemical structure alone.

  12. Prokaryotic Responses to Ammonium and Organic Carbon Reveal Alternative CO2 Fixation Pathways and Importance of Alkaline Phosphatase in the Mesopelagic North Atlantic

    PubMed Central

    Baltar, Federico; Lundin, Daniel; Palovaara, Joakim; Lekunberri, Itziar; Reinthaler, Thomas; Herndl, Gerhard J.; Pinhassi, Jarone

    2016-01-01

    To decipher the response of mesopelagic prokaryotic communities to input of nutrients, we tracked changes in prokaryotic abundance, extracellular enzymatic activities, heterotrophic production, dark dissolved inorganic carbon (DIC) fixation, community composition (16S rRNA sequencing) and community gene expression (metatranscriptomics) in 3 microcosm experiments with water from the mesopelagic North Atlantic. Responses in 3 different treatments amended with thiosulfate, ammonium or organic matter (i.e., pyruvate plus acetate) were compared to unamended controls. The strongest stimulation was found in the organic matter enrichments, where all measured rates increased >10-fold. Strikingly, in the organic matter treatment, the dark DIC fixation rates—assumed to be related to autotrophic metabolisms—were equally stimulated as all the other heterotrophic-related parameters. This increase in DIC fixation rates was paralleled by an up-regulation of genes involved in DIC assimilation via anaplerotic pathways. Alkaline phosphatase was the metabolic rate most strongly stimulated and its activity seemed to be related to cross-activation by nonpartner histidine kinases, and/or the activation of genes involved in the regulation of elemental balance during catabolic processes. These findings suggest that episodic events such as strong sedimentation of organic matter into the mesopelagic might trigger rapid increases of originally rare members of the prokaryotic community, enhancing heterotrophic and autotrophic carbon uptake rates, ultimately affecting carbon cycling. Our experiments highlight a number of fairly unstudied microbial processes of potential importance in mesopelagic waters that require future attention. PMID:27818655

  13. Management of Spent Organic Ion-Exchange Resins by Photochemical Oxidation

    SciTech Connect

    Srinivas, C.; Sugilal, S.; Wattal, P. K.

    2003-02-26

    Management of spent ion-exchange resin waste arising from nuclear reactor operations by traditional practice of encapsulation in cement is associated with problems such as swelling and disintegration. Complete oxidation (mineralization) is an attractive alternative option. This paper reports the development of photochemical mineralization process for organic ion-exchange resins of poly (styrene-divinyl benzene) type with sulfonic acid and quaternary ammonium functional groups. It is a two-step process consisting of dissolution (conversion of solid resin into water-soluble reaction products) and photo-Fenton mineralization of the dissolved resin. Cation and anion resin dissolution was effected by reaction of the resin with H2O2 at 50-60 C in the presence of ferrous/copper sulphate catalyst. Direct dissolution of mixed resin was not efficient. However, the cation resin portion in the mixed resin could be selectively dissolved without affecting the anion portion. The solid anion resin after separation from the cation resin solution could be dissolved. About 0.5 liters of 50% H2O2 was required for dissolution of one kg of wet resin. The reaction time was 4-5 hours. Dissolution experiments were conducted on up to 8 liters of wet resin. The second step, viz., photo-Fenton mineralization of the dissolved resin was effected at ambient temperature(25-35 C). Kinetic results of laboratory scale experiments in immersion type photo-reactor and pilot scale experiments in tubular flow photo-reactor were presented. These results clearly demonstrated the photo-Fenton mineralization of dissolved resin at ambient temperature with stoichiometric quantity of H2O2 as against 70-200% excess H2O2 requirement in chemical mineralization experiments under Fenton oxidation conditions at 90-95 C. Based on these studies, a treatment scheme was developed and presented in this paper.

  14. Clinoptilolite: a possible support material for nitrifying biofilms for effective control of ammonium effluent quality?

    PubMed

    Inan, H; Beler Baykal, B

    2005-01-01

    Ammonium selective natural zeolite clinoptilolite is suggested as a possible support material for nitrifying biofilms to help improve effluent ammonium quality through its high capacity of ammonium removal in the process of ion exchange. This will especially be helpful in cases where the biofilter receives peak or variable loads routinely or occasionally. At the time of peak loads or shocks of ammonium, ion exchange capacity will provide a buffer for the effluent ammonium quality. Data to support this suggestion is presented.

  15. Ion Dynamics in Organic-Inorganic Composite Superionic Conductor Glasses

    SciTech Connect

    Asayama, Ryo; Kuwata, Naoaki; Kawamura, Junichi

    2006-05-05

    Ionic conductivity of organic-inorganic composite superionic conductor glasses composed of AgI and alkylammoniumiodides is measured as a function of frequency, temperature and composition. A clear transition from insulator to superionic conductor is confirmed at the volume fraction {phi} of AgI is about 35 %. The dc component of the conductivity is fitted to the {sigma}{approx}({phi}-{phi}c){mu} with {phi}c=0.36, {mu}=2.5 for the present data. Near the percolation threshold, a power-law type frequency dependence of {omega}n (n{approx}0.67) is seen in mid frequency and {omega}1.0 at higher frequency corresponding to the constant loss region power-law is observed. The activation energies and preexponential factors derived from the temperature dependence increase from 0.3 to 0.7 eV approaching to the threshold. From these results, the ion dynamics in these glasses can be explained by the static site percolation theory at first approximation, but require the consideration on the chemical bond variation between the Ag and I modified by the organic ions.

  16. Electrospray droplet exposure to organic vapors: metal ion removal from proteins and protein complexes.

    PubMed

    DeMuth, J Corinne; McLuckey, Scott A

    2015-01-20

    The exposure of aqueous nanoelectrospray droplets to various organic vapors can dramatically reduce sodium adduction on protein ions in positive ion mass spectra. Volatile alcohols, such as methanol, ethanol, and isopropanol lead to a significant reduction in sodium ion adduction but are not as effective as acetonitrile, acetone, and ethyl acetate. Organic vapor exposure in the negative ion mode, on the other hand, has essentially no effect on alkali ion adduction. Evidence is presented to suggest that the mechanism by which organic vapor exposure reduces alkali ion adduction in the positive mode involves the depletion of alkali metal ions via ion evaporation of metal ions solvated with organic molecules. The early generation of metal/organic cluster ions during the droplet desolvation process results in fewer metal ions available to condense on the protein ions formed via the charged residue mechanism. These effects are demonstrated with holomyoglobin ions to illustrate that the metal ion reduction takes place without detectable protein denaturation, which might be revealed by heme loss or an increase in charge state distribution. No evidence is observed for denaturation with exposure to any of the organic vapors evaluated in this work.

  17. Ammonium nonanoate broadcast application over onions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ammonium nonanoate occurs in nature and is primarily formed from biodegradation of higher fatty acids. Racer (40% ammonium nonaoate) is a potential contact herbicide for weed control in organic crop production. Field research was conducted in southeast Oklahoma (Atoka County, Lane, OK) to determin...

  18. Biodegradation of rocket propellant waste, ammonium perchlorate

    NASA Technical Reports Server (NTRS)

    Naqvi, S. M. Z.; Latif, A.

    1975-01-01

    The short term effects of ammonium perchlorate on selected organisms were studied. A long term experiment was also designed to assess the changes incurred by ammonium perchlorate on the nitrogen and chloride contents of soil within a period of 3 years. In addition, an attempt was made to produce methane gas from anaerobic fermentation of the aquatic weed, Alternanthera philoxeroides.

  19. Insensitive Ammonium Nitrate.

    DTIC Science & Technology

    is reduced by replacing the ammonium nitrate with a solid solution of potassium nitrate in form III ammonium nitrate wherein the potassium nitrate...constitutes from more than zero to less than 50 weight percent of the solid solution . (Author)

  20. SECONDARY ORGANIC AEROSOL FORMATION FROM THE OXIDATION OF AROMATIC HYDROCARBONS IN THE PRESENCE OF DRY SUBMICRON AMMONIUM SULFATE AEROSOL

    EPA Science Inventory

    A laboratory study was conducted to examine formation of secondary organic aerosols. A smog chamber system was developed for studying gas-aerosol interactions in a dynamic flow reactor. These experiments were conducted to investigate the fate of gas and aerosol phase compounds ...

  1. Modification of a Na-montmorillonite with quaternary ammonium salts and its application for organics removal from TNT red water.

    PubMed

    Zhang, Qian; Meng, Zilin; Zhang, Yihe; Lv, Guocheng; Lv, Fengzhu; Wu, Limei

    2014-01-01

    Na-montmorillonite (Na-Mont) and organic montmorillonite modified by cetyltrimethylammonium bromide (CTAB-Mont) and tetramethylammonium bromide (TMAB-Mont) were prepared as adsorbents to remove organic contaminants from 2,4,6-trinitrotoluene (TNT) red water. The characterizations of the samples were performed with X-ray diffraction and Fourier transform infrared spectroscopy. The adsorption capacity of CTAB-Mont (15.9 mg/g) was much larger than Na-Mont (0.26 mg/g) and TMAB-Mont (1.7 mg/g). Langmuir isotherm and the pseudo-second-order kinetic models fitted the experimental results well. The main factor in the adsorption promotion was the distribution phase in the interlayer of CTAB-Mont. The arrangement of molecules analyzed by molecular simulation corresponded to the experimental data and supported the adsorption mechanism.

  2. ATR-FTIR characterization of organic functional groups and inorganic ions in ambient aerosols at a rural site

    NASA Astrophysics Data System (ADS)

    Coury, Charity; Dillner, Ann M.

    An Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopic method was used to measure organic functional groups and inorganic ions at Tonto National Monument (TNM), an Interagency Monitoring of Protected Visual Environments (IMPROVE) sampling site in a rural area near Phoenix, Arizona. Functional groups and ions from common aerosol compound classes such as aliphatic and aromatic CH, methylene, methyl, aldehydes/ketones, carboxylic acids, ammonium sulfate and nitrate as well as functional groups from difficult to measure compound classes such as esters/lactones, acid anhydrides, carbohydrate hydroxyl and ethers, amino acids, and amines were quantified. On average, ˜33% of the PM 1.0 mass was composed of organic aerosol. The average (standard deviation) composition of the organic aerosol at TNM was 34% (6%) biogenic functional groups, 21% (5%) oxygenated functional groups, 28% (7%) aliphatic hydrocarbon functional groups (aliphatic CH, methylene and methyl) and 17% (1%) aromatic hydrocarbon functional groups. Compositional analysis, functional group correlations, and back trajectories were used to identify three types of events with source signatures: primary biogenic-influenced, urban-influenced, and regional background. The biogenic-influenced event had high concentrations of amino acids and carbohydrate hydroxyl and ether, as well as aliphatic CH and aromatic CH functional groups and qualitatively high levels of silicate. The urban-influenced events had back trajectories traveling directly from the Phoenix area and high concentrations of hydrocarbons, oxygenated functional groups, and inorganic ions. This aerosol characterization suggests that both primary emissions in Phoenix and secondary formation of aerosols from Phoenix emissions had a major impact on the aerosol composition and concentration at TNM. The regional background source had low concentrations of all functional groups, but had higher concentrations of biogenic functional

  3. Response of removal rates to various organic carbon and ammonium loads in laboratory-scale constructed wetlands treating artificial wastewater.

    PubMed

    Wu, Shubiao; Kuschk, Peter; Wiessner, Arndt; Kästner, Matthias; Pang, Changle; Dong, Renjie

    2013-01-01

    High levels (92 and 91%) of organic carbon were successfully removed from artificial wastewater by a laboratory-scale constructed wetland under inflow loads of 670 mg/m2 x d (100 mg/d) and 1600 mg/m2d (240 mg/d), respectively. Acidification to pH 3.0 was observed at the low organic carbon load, which further inhibited the denitrification process. An increase in carbon load, however, was associated with a significant elevation of pH to 6.0. In general, sulfate and nitrate reduction were relatively high, with mean levels of 87 and 90%, respectively. However, inhibition of nitrification was initiated with an increase in carbon loads. This effect was probably a result of competition for oxygen by heterotrophic bacteria and an inhibitory effect of sulfide (S2) toxicity (concentration approximately 3 mg/L). In addition, numbers of healthy stalks of Juncus effusus (common rush) decreased from 14 000 to 10 000/m2 with an increase of sulfide concentration, indicating the negative effect of sulfide toxicity on the wetland plants.

  4. Ammonium toxicity at high pH in a marine bioassay using Corophium volutator.

    PubMed

    Kater, Belinda J; Dubbeldam, Marco; Postma, Jaap F

    2006-10-01

    Two forms of ammonium exist in water: un-ionized ammonia NH3 and ionized ammonium NH4+. The toxicity to many aquatic organisms is primarily attributed to the NH3 (un-ionized) species, with the NH4+ ion (ionized) species being relatively less toxic. The pH level influences the degree of ionization. It is therefore very important that quality criteria be derived for total ammonium levels at several pH values in order to allow correct interpretation of the sediment bioassay with Corophium volutator. The responses of Corophium to total ammonium were studied in a series of pH-controlled experiments. The LC50 of total ammonium showed a significant decrease with increasing pH, in both water-only and sediment experiments. The results indicated a combined NH4+ and NH3 toxicity at pH levels less than 8.3. The results can be used to set pH-dependent water quality criteria for total ammonium in overlying water in a 10-day sediment bioassay with Corophium volutator.

  5. Crystal structure of the heptamolybdate(VI) (paramolybdate) ion, [Mo7O24]6-, in the ammonium and potassium tetrahydrate salts

    USGS Publications Warehouse

    Evans, H.T.; Gatehouse, B.M.; Leverett, P.

    1975-01-01

    The crystal structures of the isomorphous salts MI6 [Mo7O24],4H2O (M = NH4 or K) have been refined by three-dimensional X-ray diffraction methods. Unit cell dimensions of these monoclinic compounds, space group P21/C with Z = 4, are, ammonium salt: a = 8.3934 ?? 0.0008, b = 36.1703 ?? 0.0045, c = 10.4715 ?? 0.0011 A??, ?? = 115.958?? ?? 0.008??; and potassium salt: a = 8.15 ?? 0.02, b = 35.68 ?? 0.1, c = 10.30 ?? 0.02 A??, ?? = 115.2?? ?? 02??. By use of multiple Weissenberg patterns, 8197 intensity data (Mo-K?? radiation) for the ammonium compound and 2178 (Cu-K?? radiation) for the potassium compound were estimated visually and used to test and refine Lindqvist's proposed structure in the space group P21/c. Lindqvist's structure was confirmed and the full matrix least-squares isotropic refinement led to R 0.076 (ammonium) 0.120 (potassium), with direct unambiguous location of the cations and water molecules in the potassium compound.

  6. Self-organized surface ripple pattern formation by ion implantation

    NASA Astrophysics Data System (ADS)

    Hofsäss, Hans; Zhang, Kun; Bobes, Omar

    2016-10-01

    Ion induced ripple pattern formation on solid surfaces has been extensively studied in the past and the theories describing curvature dependent ion erosion as well as redistribution of recoil atoms have been very successful in explaining many features of the pattern formation. Since most experimental studies use noble gas ion irradiation, the incorporation of the ions into the films is usually neglected. In this work we show that the incorporation or implantation of non-volatile ions also leads to a curvature dependent term in the equation of motion of a surface height profile. The implantation of ions can be interpreted as a negative sputter yield; and therefore, the effect of ion implantation is opposite to the one of ion erosion. For angles up to about 50°, implantation of ions stabilizes the surface, whereas above 50°, ion implantation contributes to the destabilization of the surface. We present simulations of the curvature coefficients using the crater function formalism and we compare the simulation results to the experimental data on the ion induced pattern formation using non-volatile ions. We present several model cases, where the incorporation of ions is a crucial requirement for the pattern formation.

  7. Characterization of particulate products for aging of ethylbenzene secondary organic aerosol in the presence of ammonium sulfate seed aerosol.

    PubMed

    Huang, Mingqiang; Zhang, Jiahui; Cai, Shunyou; Liao, Yingmin; Zhao, Weixiong; Hu, Changjin; Gu, Xuejun; Fang, Li; Zhang, Weijun

    2016-09-01

    Aging of secondary organic aerosol (SOA) particles formed from OH- initiated oxidation of ethylbenzene in the presence of high mass (100-300μg/m(3)) concentrations of (NH4)2SO4 seed aerosol was investigated in a home-made smog chamber in this study. The chemical composition of aged ethylbenzene SOA particles was measured using an aerosol laser time-of-flight mass spectrometer (ALTOFMS) coupled with a Fuzzy C-Means (FCM) clustering algorithm. Experimental results showed that nitrophenol, ethyl-nitrophenol, 2,4-dinitrophenol, methyl glyoxylic acid, 5-ethyl-6-oxo-2,4-hexadienoic acid, 2-ethyl-2,4-hexadiendioic acid, 2,3-dihydroxy-5-ethyl-6-oxo-4-hexenoic acid, 1H-imidazole, hydrated N-glyoxal substituted 1H-imidazole, hydrated glyoxal dimer substituted imidazole, 1H-imidazole-2-carbaldehyde, N-glyoxal substituted hydrated 1H-imidazole-2-carbaldehyde and high-molecular-weight (HMW) components were the predominant products in the aged particles. Compared to the previous aromatic SOA aging studies, imidazole compounds, which can absorb solar radiation effectively, were newly detected in aged ethylbenzene SOA in the presence of high concentrations of (NH4)2SO4 seed aerosol. These findings provide new information for discussing aromatic SOA aging mechanisms.

  8. Ion-Exclusion Chromatography for Analyzing Organics in Water

    NASA Technical Reports Server (NTRS)

    Sauer, Richard; Rutz, Jeffrey A.; Schultz, John R.

    2006-01-01

    A liquid-chromatography technique has been developed for use in the quantitative analysis of urea (and of other nonvolatile organic compounds typically found with urea) dissolved in water. The technique involves the use of a column that contains an ion-exclusion resin; heretofore, this column has been sold for use in analyzing monosaccharides and food softeners, but not for analyzing water supplies. The prior technique commonly used to analyze water for urea content has been one of high-performance liquid chromatography (HPLC), with reliance on hydrophobic interactions between analytes in a water sample and long-chain alkyl groups bonded to an HPLC column. The prior technique has proven inadequate because of a strong tendency toward co-elution of urea with other compounds. Co-elution often causes the urea and other compounds to be crowded into a narrow region of the chromatogram (see left part of figure), thereby giving rise to low chromatographic resolution and misidentification of compounds. It is possible to quantitate urea or another analyte via ultraviolet- and visible-light absorbance measurements, but in order to perform such measurements, it is necessary to dilute the sample, causing a significant loss of sensitivity. The ion-exclusion resin used in the improved technique is sulfonated polystyrene in the calcium form. Whereas the alkyl-chain column used in the prior technique separates compounds on the basis of polarity only, the ion-exclusion-resin column used in the improved technique separates compounds on the basis of both molecular size and electric charge. As a result, the degree of separation is increased: instead of being crowded together into a single chromatographic peak only about 1 to 2 minutes wide as in the prior technique, the chromatographic peaks of different compounds are now separated from each other and spread out over a range about 33 minutes wide (see right part of figure), and the urea peak can readily be distinguished from the other

  9. Comparison of mono- and polyatomic primary ions for the characterization of organic dye overlayers with static secondary ion mass spectrometry.

    PubMed

    Lenaerts, Jens; Van Vaeck, Luc; Gijbels, Renaat; Van Luppen, Jaymes

    2004-01-01

    Organic carbocyanine dye coatings have been analyzed by time-of-flight static secondary ion mass spectrometry (TOF-S-SIMS) using three types of primary ions: Ga(+) operating at 25 keV, and Xe(+) and SF(5) (+) both operating at 9 keV. Secondary ion yields obtained with these three primary ions have been compared for coatings with different layer thickness, varying from (sub)-monolayer to multilayers, on different substrates (Si, Ag and AgBr cubic microcrystals). For (sub)-monolayers deposited on Ag, Xe(+) and SF(5) (+) primary ions generate similar precursor ion intensities, but with Ga(+) slightly lower precursor ion intensities were obtained. Thick coatings on Ag as well as mono- and multilayers on Si produce the highest precursor and fragment ion intensities with the polyatomic primary ion. The yield difference between SF(5) (+) and Xe(+) can reach a factor of 6. In comparison with Ga(+), yield enhancements by up to a factor of 180 are observed with SF(5) (+). For the mass spectrometric analysis of dye layers on AgBr microcrystals, SF(5) (+) again proves to be the primary ion of choice.

  10. Hybrid Organic/Inorganic Materials Depth Profiling Using Low Energy Cesium Ions

    NASA Astrophysics Data System (ADS)

    Noël, Céline; Houssiau, Laurent

    2016-05-01

    The structures developed in organic electronics, such as organic light emitting diodes (OLEDs) or organic photovoltaics (OPVs) devices always involve hybrid interfaces, joining metal or oxide layers with organic layers. No satisfactory method to probe these hybrid interfaces physical chemistry currently exists. One promising way to analyze such interfaces is to use in situ ion beam etching, but this requires ion beams able to depth profile both inorganic and organic layers. Mono- or diatomic ion beams commonly used to depth profile inorganic materials usually perform badly on organics, while cluster ion beams perform excellently on organics but yield poor results when organics and inorganics are mixed. Conversely, low energy Cs+ beams (<500 eV) allow organic and inorganic materials depth profiling with comparable erosion rates. This paper shows a successful depth profiling of a model hybrid system made of metallic (Au, Cr) and organic (tyrosine) layers, sputtered with 500 eV Cs+ ions. Tyrosine layers capped with metallic overlayers are depth profiled easily, with high intensities for the characteristic molecular ions and other specific fragments. Metallic Au or Cr atoms are recoiled into the organic layer where they cause some damage near the hybrid interface as well as changes in the erosion rate. However, these recoil implanted metallic atoms do not appear to severely degrade the depth profile overall quality. This first successful hybrid depth profiling report opens new possibilities for the study of OLEDs, organic solar cells, or other hybrid devices.

  11. Hybrid Organic/Inorganic Materials Depth Profiling Using Low Energy Cesium Ions.

    PubMed

    Noël, Céline; Houssiau, Laurent

    2016-05-01

    The structures developed in organic electronics, such as organic light emitting diodes (OLEDs) or organic photovoltaics (OPVs) devices always involve hybrid interfaces, joining metal or oxide layers with organic layers. No satisfactory method to probe these hybrid interfaces physical chemistry currently exists. One promising way to analyze such interfaces is to use in situ ion beam etching, but this requires ion beams able to depth profile both inorganic and organic layers. Mono- or diatomic ion beams commonly used to depth profile inorganic materials usually perform badly on organics, while cluster ion beams perform excellently on organics but yield poor results when organics and inorganics are mixed. Conversely, low energy Cs(+) beams (<500 eV) allow organic and inorganic materials depth profiling with comparable erosion rates. This paper shows a successful depth profiling of a model hybrid system made of metallic (Au, Cr) and organic (tyrosine) layers, sputtered with 500 eV Cs(+) ions. Tyrosine layers capped with metallic overlayers are depth profiled easily, with high intensities for the characteristic molecular ions and other specific fragments. Metallic Au or Cr atoms are recoiled into the organic layer where they cause some damage near the hybrid interface as well as changes in the erosion rate. However, these recoil implanted metallic atoms do not appear to severely degrade the depth profile overall quality. This first successful hybrid depth profiling report opens new possibilities for the study of OLEDs, organic solar cells, or other hybrid devices.

  12. Organic electrochemical transistor array for recording transepithelial ion transport of human airway epithelial cells.

    PubMed

    Yao, Chunlei; Xie, Changyan; Lin, Peng; Yan, Feng; Huang, Pingbo; Hsing, I-Ming

    2013-12-03

    An organic electrochemical transistor array is integrated with human airway epithelial cells. This integration provides a novel method to couple transepithelial ion transport with electrical current. Activation and inhibition of transepithelial ion transport are readily detected with excellent time resolution. The organic electrochemical transistor array serves as a promising platform for physiological studies and drug testing.

  13. Biocidal quaternary ammonium resin

    NASA Technical Reports Server (NTRS)

    Janauer, G. E.

    1983-01-01

    Activated carbon (charcoal) and polymeric resin sorbents are widely used in the filtration and treatment of drinking water, mainly to remove dissolved organic and inorganic impurities and to improve the taste. Earlier hopes that activated carbon might "disinfect' water proved to be unfounded. The feasibility of protecting against microbial infestation in charcoal and resin beds such as those to be incorporated into total water reuse systems in spacecraft was investigated. The biocidal effect of IPCD (insoluable polymeric contact disinfectants) in combination with a representative charcoal was assessed. The ion exchange resins (IPCD) were shown to adequately protect charcoal and ion exchange beds.

  14. Effects of exposure to quaternary-ammonium-based biocides on antimicrobial susceptibility and tolerance to physical stresses in bacteria from organic foods.

    PubMed

    Gadea, Rebeca; Fernández Fuentes, Miguel Ángel; Pérez Pulido, Rubén; Gálvez, Antonio; Ortega, Elena

    2017-05-01

    In the present study, a collection of 76 biocide-sensitive bacterial strains isolated from organically produced food were adapted by repeated exposure to increasing concentrations of the quaternary ammonium compounds (QACs) benzalkonium chloride (BC) and hexadecylpyridinium chloride (HDP). The sensitivity of both wildtype strains and their corresponding QAC-adapted strains to other biocides and to antibiotics was studied. QAC tolerance increased in 88.2% of strains for BC and in 30.3% of strains for HDP, with increases in minimum inhibitory concentrations between 2 and over 100 fold. Adaptive resistance was stable after 20 subcultures in biocide-free medium for 7 and 5 of the BC- and HDP-adapted strains, respectively. Adaptation to BC and HDP also reduced the susceptibility to other biocides, mainly hexachlorophene (CF), didecyldimethylammonium bromide (AB), triclosan (TC) and chlorhexidine (CH). BC-adapted strains showed increased antibiotic resistance to ampicillin (AM) followed by sulfamethoxazol (SXT) and cefotaxime (CTX), and some showed increased sensitivity to ceftazidime (CAZ), CTX, AM and STX. Changes in antibiotic resistance in HDP-adapted strains were more heterogeneous and strain-dependent. Main efflux pump genes detected in QAC-adapted strains were acrB, sugE, norC, qacE and qacH, as well as antibiotic resistance genes aac(6_)-Ie-aph(2_)-Ia, aph(2_)-Ic, ant(4_)-Ia, lsa, mrsA/B, ereA, ermB and cat. Membrane anisotropy experiments revealed that QAC adaptation induced an increase in membrane rigidity in the case of BC, while response to HDP was more heterogeneous and strain-dependent. Growth capacity was significantly higher in some QAC-adapted strains and strain-dependent changes in heat tolerance were also detected in QAC-adapted strains. Gastric acid or bile resistances do not seem to be influenced by QAC adaptation.

  15. Gas molecule scattering & ion mobility measurements for organic macro-ions in He versus N2 environments.

    PubMed

    Larriba-Andaluz, Carlos; Fernández-García, Juan; Ewing, Michael A; Hogan, Christopher J; Clemmer, David E

    2015-06-14

    (internal motion), while in the case of N2, individual gas molecules have sufficiently large momentum to alter the internal motion in organic ions.

  16. Long-range transported dissolved organic matter, ions and black carbon deposited on Central Asian snow covered glaciers

    NASA Astrophysics Data System (ADS)

    Schmale, Julia; Kang, Shichang; Peltier, Richard

    2014-05-01

    Ninety percent of the Central Asian population depend on water precipitated in the mountains stored in glaciers and snow cover. Accelerated melting of the snow and ice can be induced by the deposition of airborne impurities such as mineral dust, black carbon and co-emitted species leading to significant reductions of the surface albedo. However, Central Asia is a relatively understudied region and data on the source regions, chemical and microphysical characteristics as well as modelling studies of long-range transported air pollution and dust to the Tien Shan mountains is very scarce. We studied the atmospheric aerosol deposited most likely between summer 2012 and summer 2013on three different glaciers in the Kyrgyz Republic. Samples were taken from four snow pits on the glaciers Abramov (2 pits, 39.59 °N, 71.56 °E, 4390 m elevation, 240 cm deep, and 39.62°N, 71.52 °E, 4275 m elevation, 125 cm deep), Ak-Shiirak (41.80 °N, 78.18 °E, 4325 m elevation, 75 cm deep) and Suek (41.78 °N, 77.75 °E, 4341 m elevation, 200 cm deep). The latter two glaciers are located roughly within 6 and 38 km of an operating gold mine. The snow was analyzed for black carbon, ions, metals and organic carbon. We here focus on the results of inorganic ion measurements and organic carbon speciation based on analysis with an Aerodyne high-resolution time-of-flight aerosol spectrometer (HR-ToF-AMS) and potential pollution sources that can be deduced from the chemical information as well as back trajectories. Average contributions of snow impurities measured by the HR-ToF-AMS were dominated by organic carbon. Relative concentrations of organic carbon, sulfate, nitrate and ammonium in snow were 86 %, 3 %, 9 % and 2 % respectively for Abramov, 92 %, 1 %, 5 % and 1 % for Suek, and 95 %, 1 %, 3 % and 1 % for Ak-Shiirak. Generally, impurities on Suek and Ak-Shiirak were three and five times higher than on Abramov. Mass concentrations of organic carbon were on average 6 times higher in samples

  17. An investigation of electrostatic interactions between organically functionalized silica particles, surfaces, and metal ions

    NASA Astrophysics Data System (ADS)

    Stahl, Sarah Margaret

    This research focuses on the electrostatic interactions between silica particles and either coated surfaces or metal ions. This work has two objectives: to begin a preliminary investigation into particle-surface systems that may be ideal for further investigation as a sensor and to investigate metal-ligand interactions for the potential use of metal ions to aid in the self assembly of silica particles. Silica particles with various organic functionalizations were synthesized from trialkoxysilane precursors using variations of the Stöber synthesis method, a well-known colloidal suspensions technique. The functional groups that were used in this work include mercaptopropyl (MPTMS), ethylenediamine (enTMOS), and aminopropyl groups (APTES). The aminopropyl functionalized particles were synthesized by varying the mol% of APTES in a tetraethoxyorthosilicate (TEOS) particle formulation. Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR) were used to analyze the particles for size, shape, and composition. Silica particles with all three functionalizations were used for the particle-surface study, whereas only MPTMS particles were used in the metal-ligand study. The coatings used for the particle-surface study were synthesized using standard sol gel chemistry with trialkoxysilane precursors as well. The functional groups used in this study include methyl (MTMOS) and aminopropyl groups (TEOS/APTES). Sol gel coatings incorporating carboxy and ammonium groups were also investigated but were not suitable for further study. FTIR was used to analyze the MTMOS and TEOS/APTES coatings. The adsorption of the MPTMS particles onto TEOS/APTES coatings and enTMOS or TEOS/APTES particles onto MTMOS coatings over time was monitored using fluorescence spectroscopy. Since silica particles are not fluorescent in the visible light range, a fluorescent dye was incorporated into the particles, either rhodamine (MPTMS particles) or pyranine dye (enTMOS, TEOS

  18. Electrospray ionization tandem mass spectrometry of ammonium cationized polyethers.

    PubMed

    Nasioudis, Andreas; Heeren, Ron M A; van Doormalen, Irene; de Wijs-Rot, Nicolette; van den Brink, Oscar F

    2011-05-01

    Quaternary ammonium salts (Quats) and amines are known to facilitate the MS analysis of high molar mass polyethers by forming low charge state adduct ions. The formation, stability, and behavior upon collision-induced dissociation (CID) of adduct ions of polyethers with a variety of Quats and amines were studied by electrospray ionization quadrupole time-of-flight, quadrupole ion trap, and linear ion trap tandem mass spectrometry (MS/MS). The linear ion trap instrument was part of an Orbitrap hybrid mass spectrometer that allowed accurate mass MS/MS measurements. The Quats and amines studied were of different degree of substitution, structure, and size. The stability of the adduct ions was related to the structure of the cation, especially the amine's degree of substitution. CID of singly/doubly charged primary and tertiary ammonium cationized polymers resulted in the neutral loss of the amine followed by fragmentation of the protonated product ions. The latter reveals information about the monomer unit, polymer sequence, and endgroup structure. In addition, the detection of product ions retaining the ammonium ion was observed. The predominant process in the CID of singly charged quaternary ammonium cationized polymers was cation detachment, whereas their doubly charged adduct ions provided the same information as the primary and tertiary ammonium cationized adduct ions. This study shows the potential of specific amines as tools for the structural elucidation of high molar mass polyethers.

  19. Electrospray Ionization Tandem Mass Spectrometry of Ammonium Cationized Polyethers

    NASA Astrophysics Data System (ADS)

    Nasioudis, Andreas; Heeren, Ron M. A.; van Doormalen, Irene; de Wijs-Rot, Nicolette; van den Brink, Oscar F.

    2011-05-01

    Quaternary ammonium salts (Quats) and amines are known to facilitate the MS analysis of high molar mass polyethers by forming low charge state adduct ions. The formation, stability, and behavior upon collision-induced dissociation (CID) of adduct ions of polyethers with a variety of Quats and amines were studied by electrospray ionization quadrupole time-of-flight, quadrupole ion trap, and linear ion trap tandem mass spectrometry (MS/MS). The linear ion trap instrument was part of an Orbitrap hybrid mass spectrometer that allowed accurate mass MS/MS measurements. The Quats and amines studied were of different degree of substitution, structure, and size. The stability of the adduct ions was related to the structure of the cation, especially the amine's degree of substitution. CID of singly/doubly charged primary and tertiary ammonium cationized polymers resulted in the neutral loss of the amine followed by fragmentation of the protonated product ions. The latter reveals information about the monomer unit, polymer sequence, and endgroup structure. In addition, the detection of product ions retaining the ammonium ion was observed. The predominant process in the CID of singly charged quaternary ammonium cationized polymers was cation detachment, whereas their doubly charged adduct ions provided the same information as the primary and tertiary ammonium cationized adduct ions. This study shows the potential of specific amines as tools for the structural elucidation of high molar mass polyethers.

  20. Electricity production coupled to ammonium in a microbial fuel cell.

    PubMed

    He, Zhen; Kan, Jinjun; Wang, Yanbing; Huang, Yuelong; Mansfeld, Florian; Nealson, Kenneth H

    2009-05-01

    The production of electricity from ammonium was examined using a rotating-cathode microbial fuel cell (MFC). The addition of ammonium chloride, ammonium sulfate, or ammonium phosphate (monobasic) resulted in electricity generation, while adding sodium chloride, nitrate, or nitrite did not cause any increase in current production. The peak current increased with increasing amount of ammonium addition up to 62.3 mM of ammonium chloride, suggesting that ammonium was involved in electricity generation either directly as the anodic fuel or indirectly as substrates for nitrifiers to produce organic compounds for heterotrophs. Adding nitrate or nitrite with ammonium increased current production compared to solely ammonium addition. Using 16S rRNA-linked molecular analyses, we found ammonium-oxidizing bacteria and denitrifying bacteria on both the anode and cathode electrodes, whereas no anammox bacteria were detected. The dominant ammonium-oxidizing bacteria were closely related to Nitrosomonas europaea. The present MFC achieved an ammonium removal efficiency of 49.2 +/- 5.9 or 69.7 +/- 3.6%, depending on hydraulic retention time, but exhibited a very low Coulombic efficiency.

  1. Alkali-metal ion coordination in uranyl(VI) poly-peroxo complexes in solution, inorganic analogues to crown-ethers. Part 2. Complex formation in the tetramethyl ammonium-, Li(+)-, Na(+)- and K(+)-uranyl(VI)-peroxide-carbonate systems.

    PubMed

    Zanonato, Pier Luigi; Szabó, Zoltán; Vallet, Valerie; Di Bernardo, Plinio; Grenthe, Ingmar

    2015-10-07

    The constitution and equilibrium constants of ternary uranyl(vi) peroxide carbonate complexes [(UO2)p(O2)q(CO3)r](2(p-q-r)) have been determined at 0 °C in 0.50 M MNO3, M = Li, K, and TMA (tetramethyl ammonium), ionic media using potentiometric and spectrophotometric data; (17)O NMR data were used to determine the number of complexes present. The formation of cyclic oligomers, "[(UO2)(O2)(CO3)]n", n = 4, 5, 6, with different stoichiometries depending on the ionic medium used, suggests that Li(+), Na(+), K(+) and TMA ions act as templates for the formation of uranyl peroxide rings where the uranyl-units are linked by μ-η(2)-η(2) bridged peroxide-ions. The templating effect is due to the coordination of the M(+)-ions to the uranyl oxygen atoms, where the coordination of Li(+) results in the formation of Li[(UO2)(O2)(CO3)]4(7-), Na(+) and K(+) in the formation of Na/K[(UO2)(O2)(CO3)]5(9-) complexes, while the large tetramethyl ammonium ion promotes the formation of two oligomers, TMA[(UO2)(O2)(CO3)]5(9-) and TMA[(UO2)(O2)(CO3)]6(11-). The NMR spectra demonstrate that the coordination of Na(+) in the five- and six-membered oligomers is significantly stronger than that of TMA(+); these observations suggest that the templating effect is similar to the one observed in the synthesis of crown-ethers. The NMR experiments also demonstrate that the exchange between TMA[(UO2)(O2)(CO3)]5(9-) and TMA[(UO2)(O2)(CO3)]6(11-) is slow on the (17)O chemical shift time-scale, while the exchange between TMA[(UO2)(O2)(CO3)]6(11-) and Na[(UO2)(O2)(CO3)]6(11-) is fast. There was no indication of the presence of large clusters of the type identified by Burns and Nyman (M. Nyman and P. C. Burns, Chem. Soc. Rev., 2012, 41, 7314-7367) and possible reasons for this and the implications for the synthesis of large clusters are briefly discussed.

  2. Phase diagram of ammonium nitrate

    NASA Astrophysics Data System (ADS)

    Dunuwille, M.; Yoo, C. S.

    2014-05-01

    Ammonium Nitrate (AN) has often subjected to uses in improvised explosive devices, due to its wide availability as a fertilizer and its capability of becoming explosive with slight additions of organic and inorganic compounds. Yet, the origin of enhanced energetic properties of impure AN (or AN mixtures) is neither chemically unique nor well understood -resulting in rather catastrophic disasters in the past1 and thereby a significant burden on safety in using ammonium nitrates even today. To remedy this situation, we have carried out an extensive study to investigate the phase stability of AN at high pressure and temperature, using diamond anvil cells and micro-Raman spectroscopy. The present results confirm the recently proposed phase IV-to-IV' transition above 17 GPa2 and provide new constraints for the melting and phase diagram of AN to 40 GPa and 400 °C.

  3. Evaluation of the impact of organic material on the anaerobic methane and ammonium removal in a membrane aerated biofilm reactor (MABR) based on the multispecies biofilm modeling.

    PubMed

    Wu, Jun; Zhang, Yue

    2017-01-01

    The simultaneous nitrogen and methane removal by the combined nitritation, anaerobic ammonium oxidation (anammox), and nitrite dependent anaerobic methane oxidation (n-damo) processes in the membrane aerated biofilm reactor (MABR) offers clear advantages in term of energy saving and greenhouse gas emission mitigation. The rejected water from sludge digestion usually contained high ammonium, COD, and dissolved methane. The impact of influent COD on the anaerobic methane and ammonium removal in an MABR was evaluated in the model based study. The results indicated that the influent COD did not reduce the methane and ammonium removal efficiency at C/N ratio (influent COD/NH4(+)-N) less than 0.1. At high C/N ratio, the oxygen transfer coefficient needed to be increased to achieve high methane and nitrogen removal. Substrate flux analysis indicated that heterotrophic denitrification in the outside layer of biofilm reduced the impact of influent COD. Heterotrophic growth needed to be limited at the outside layer by using NO3(-) as electron acceptor; otherwise, the heterotrophic bacteria would compete NO2(-) and space with anammox and n-damo bacteria in the inner layers and reduce the nitrogen and methane removal efficiency.

  4. A single-cell view of ammonium assimilation in coral-dinoflagellate symbiosis.

    PubMed

    Pernice, Mathieu; Meibom, Anders; Van Den Heuvel, Annamieke; Kopp, Christophe; Domart-Coulon, Isabelle; Hoegh-Guldberg, Ove; Dove, Sophie

    2012-07-01

    Assimilation of inorganic nitrogen from nutrient-poor tropical seas is an essential challenge for the endosymbiosis between reef-building corals and dinoflagellates. Despite the clear evidence that reef-building corals can use ammonium as inorganic nitrogen source, the dynamics and precise roles of host and symbionts in this fundamental process remain unclear. Here, we combine high spatial resolution ion microprobe imaging (NanoSIMS) and pulse-chase isotopic labeling in order to track the dynamics of ammonium incorporation within the intact symbiosis between the reef-building coral Acropora aspera and its dinoflagellate symbionts. We demonstrate that both dinoflagellate and animal cells have the capacity to rapidly fix nitrogen from seawater enriched in ammonium (in less than one hour). Further, by establishing the relative strengths of the capability to assimilate nitrogen for each cell compartment, we infer that dinoflagellate symbionts can fix 14 to 23 times more nitrogen than their coral host cells in response to a sudden pulse of ammonium-enriched seawater. Given the importance of nitrogen in cell maintenance, growth and functioning, the capability to fix ammonium from seawater into the symbiotic system may be a key component of coral nutrition. Interestingly, this metabolic response appears to be triggered rapidly by episodic nitrogen availability. The methods and results presented in this study open up for the exploration of dynamics and spatial patterns associated with metabolic activities and nutritional interactions in a multitude of organisms that live in symbiotic relationships.

  5. Structural study of ammonium metatungstate

    SciTech Connect

    Christian, Joel B. Whittingham, M. Stanley

    2008-08-15

    Several techniques have been used to study the structure of the Keggin-type polyoxometalate salt ammonium metatungstate (AMT)-(NH{sub 4}){sub 6}[H{sub 2}W{sub 12}O{sub 40}]*nH{sub 2}O, a potential fuel cell catalyst. The dehydrated salt is comprised of a mixture of crystallites of different unit cells in a centered eutactic cubic configuration, with an average unit cell of a{approx_equal}12.295. Varied orientations of the Keggin ions in the cubic arrangement create the differences, and orientational variation within each unit cell size represents an energy well. Progressive hydration of each crystallite leads to expansion of the lattice, with the degree of expansion depending on the locations of the water added in relation to the Keggin ion, which is influenced by cation location and hydrogen bonding. The structural hypothesis is supported by electron diffraction of single and multicrystal samples, by powder density measurements, X-ray powder diffraction studies, synchrotron powder X-ray diffraction, and a priori structural modeling studies. Based on the structure, projected active site densities are compared with nanostructured platinum catalysts for fuel cell application. - Graphical abstract: The structure of ammonium metatungstate powders are highly dependent on hydration and POM molecule rotation, with cation and hydrogen bonding forces directing a mixture of structures that have been studied with bulk and single-crystal methods. The illustration shows Monte Carlo simulated anion structural disorder for the fully dehydrated form of the title compound.

  6. Evaluation of surface damage on organic materials irradiated with Ar cluster ion beam

    NASA Astrophysics Data System (ADS)

    Yamamoto, Y.; Ichiki, K.; Ninomiya, S.; Seki, T.; Aoki, T.; Matsuo, J.

    2011-01-01

    The sputtering yields of organic materials under large cluster ion bombardment are much higher than those under conventional monomer ion bombardment. The sputtering rate of arginine remains constant with fluence for an Ar cluster ion beam, but decreases with fluence for Ar monomer. Additionally, because Ar cluster etching induces little damage, Ar cluster ion can be used to achieve molecular depth profiling of organic materials. In this study, we evaluated the damage to poly methyl methacrylate (PMMA) and arginine samples irradiated with Ar atomic and Ar cluster ion beams. Arginine samples were analyzed by secondary ion mass spectrometry (SIMS) and PMMA samples were analyzed by X-ray photoelectron spectroscopy (XPS). The chemical structure of organic materials remained unchanged after Ar cluster irradiation, but was seriously damaged. These results indicated that bombardment with Ar cluster ions induced less surface damage than bombardment with Ar atomic ion. The damage layer thickness with 5 keV Ar cluster ion bombardment was less than 1 nm.

  7. Evaluation of surface damage on organic materials irradiated with Ar cluster ion beam

    SciTech Connect

    Yamamoto, Y.; Ichiki, K.; Ninomiya, S.; Matsuo, J.; Seki, T.; Aoki, T.

    2011-01-07

    The sputtering yields of organic materials under large cluster ion bombardment are much higher than those under conventional monomer ion bombardment. The sputtering rate of arginine remains constant with fluence for an Ar cluster ion beam, but decreases with fluence for Ar monomer. Additionally, because Ar cluster etching induces little damage, Ar cluster ion can be used to achieve molecular depth profiling of organic materials. In this study, we evaluated the damage to poly methyl methacrylate (PMMA) and arginine samples irradiated with Ar atomic and Ar cluster ion beams. Arginine samples were analyzed by secondary ion mass spectrometry (SIMS) and PMMA samples were analyzed by X-ray photoelectron spectroscopy (XPS). The chemical structure of organic materials remained unchanged after Ar cluster irradiation, but was seriously damaged. These results indicated that bombardment with Ar cluster ions induced less surface damage than bombardment with Ar atomic ion. The damage layer thickness with 5 keV Ar cluster ion bombardment was less than 1 nm.

  8. Electrolyte-gated organic field-effect transistor for selective reversible ion detection.

    PubMed

    Schmoltner, Kerstin; Kofler, Johannes; Klug, Andreas; List-Kratochvil, Emil J W

    2013-12-17

    An ion-sensitive electrolyte-gated organic field-effect transistor for selective and reversible detection of sodium (Na(+) ) down to 10(-6) M is presented. The inherent low voltage - high current operation of these transistors in combination with a state-of-the-art ion-selective membrane proves to be a novel, versatile modular sensor platform.

  9. Heavy ion contributions to organ dose equivalent for the 1977 galactic cosmic ray spectrum

    NASA Astrophysics Data System (ADS)

    Walker, Steven A.; Townsend, Lawrence W.; Norbury, John W.

    2013-05-01

    Estimates of organ dose equivalents for the skin, eye lens, blood forming organs, central nervous system, and heart of female astronauts from exposures to the 1977 solar minimum galactic cosmic radiation spectrum for various shielding geometries involving simple spheres and locations within the Space Transportation System (space shuttle) and the International Space Station (ISS) are made using the HZETRN 2010 space radiation transport code. The dose equivalent contributions are broken down by charge groups in order to better understand the sources of the exposures to these organs. For thin shields, contributions from ions heavier than alpha particles comprise at least half of the organ dose equivalent. For thick shields, such as the ISS locations, heavy ions contribute less than 30% and in some cases less than 10% of the organ dose equivalent. Secondary neutron production contributions in thick shields also tend to be as large, or larger, than the heavy ion contributions to the organ dose equivalents.

  10. Racer (Ammonium Nonanoate) weed control evaluation for onions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Racer has been labeled as a herbicide for food use and is currently under consideration as an organic herbicide for organically grown food crops. The main component (40%) of Racer is ammonium nonanoate (ammonium pelargonate), which occurs in nature and primarily formed from biodegradation of higher...

  11. Mild ammonium stress increases chlorophyll content in Arabidopsis thaliana.

    PubMed

    Sanchez-Zabala, Joseba; González-Murua, Carmen; Marino, Daniel

    2015-01-01

    Nitrate (NO3(-)) and ammonium (NH4(+)) are the main forms of nitrogen available in the soil for plants. Excessive NH4(+) accumulation in tissues is toxic for plants and exclusive NH4(+)-based nutrition enhances this effect. Ammonium toxicity syndrome commonly includes growth impairment, ion imbalance and chlorosis among others. In this work, we observed high intraspecific variability in chlorophyll content in 47 Arabidopsis thaliana natural accessions grown under 1 mM NH4(+) or 1 mM NO3(-) as N-source. Interestingly, chlorophyll content increased in every accession upon ammonium nutrition. Moreover, this increase was independent of ammonium tolerance capacity. Thus, chlorosis seems to be an exclusive effect of severe ammonium toxicity while mild ammonium stress induces chlorophyll accumulation.

  12. Ammonium nitrate explosive systems

    DOEpatents

    Stinecipher, Mary M.; Coburn, Michael D.

    1981-01-01

    Novel explosives which comprise mixtures of ammonium nitrate and an ammonium salt of a nitroazole in desired ratios are disclosed. A preferred nitroazole is 3,5-dinitro-1,2,4-triazole. The explosive and physical properties of these explosives may readily be varied by the addition of other explosives and oxidizers. Certain of these mixtures have been found to act as ideal explosives.

  13. Control of Diapause by Acidic pH and Ammonium Accumulation in the Hemolymph of Antarctic Copepods

    PubMed Central

    Schründer, Sabine; Schnack-Schiel, Sigrid B.; Auel, Holger; Sartoris, Franz Josef

    2013-01-01

    Life-cycles of polar herbivorous copepods are characterised by seasonal/ontogenetic vertical migrations and diapause to survive periods of food shortage during the long winter season. However, the triggers of vertical migration and diapause are still far from being understood. In this study, we test the hypothesis that acidic pH and the accumulation of ammonium (NH4+) in the hemolymph contribute to the control of diapause in certain Antarctic copepod species. In a recent study, it was already hypothesized that the replacement of heavy ions by ammonium is necessary for diapausing copepods to achieve neutral buoyancy at overwintering depth. The current article extends the hypothesis of ammonium-aided buoyancy by highlighting recent findings of low pH values in the hemolymph of diapausing copepods with elevated ammonium concentrations. Since ammonia (NH3) is toxic to most organisms, a low hemolymph pH is required to maintain ammonium in the less toxic ionized form (NH4+). Recognizing that low pH values are a relevant factor reducing metabolic rate in other marine invertebrates, the low pH values found in overwintering copepods might not only be a precondition for ammonium accumulation, but in addition, it may insure metabolic depression throughout diapause. PMID:24143238

  14. Nutrient release and ammonium sorption by poultry litter and wood biochars in stormwater treatment.

    PubMed

    Tian, Jing; Miller, Valentina; Chiu, Pei C; Maresca, Julia A; Guo, Mingxin; Imhoff, Paul T

    2016-05-15

    The feasibility of using biochar as a filter medium in stormwater treatment facilities was evaluated with a focus on ammonium retention. Successive batch extractions and batch ammonium sorption experiments were conducted in both deionized (DI) water and artificial stormwater using poultry litter (PL) and hardwood (HW) biochars pyrolyzed at 400°C and 500°C. No measureable nitrogen leached from HW biochars except 0.07 μmol/g of org-N from 400°C HW biochar. PL biochar pyrolyzed at 400°C leached 120-127 μmol/g of nitrogen but only 7.1-8.6 μmol/g of nitrogen when pyrolyzed at 500°C. Ammonium sorption was significant for all biochars. At a typical ammonium concentration of 2mg/L in stormwater, the maximum sorption was 150 mg/kg for PL biochar pryolyzed at 400°C. In stormwater, ion competition (e.g. Ca(2+)) suppressed ammonium sorption compared to DI water. Surprisingly, ammonium sorption was negatively correlated to the BET surface area of the tested biochars, but increased linearly with cation exchange capacity. Cation exchange capacity was the primary mechanism controlling ammonium sorption and was enhanced by pyrolysis at 400°C, while BET surface area was enhanced by pyrolysis at 500°C. The optimal properties (BET surface area, CEC, etc.) of biochar as a sorbent are not fixed but depend on the target pollutant. Stormwater infiltration column experiments in sand with 10% biochar removed over 90% of ammonium with influent ammonium concentration of 2mg/L, compared to only 1.7% removal in a sand-only column, indicating that kinetic limitations on sorption were minor for the storm conditions studied. Hardwood and poultry litter biochar pyrolyzed at 500°C and presumably higher temperature may be viable filter media for stormwater treatment facilities, as they showed limited release of organic and inorganic nutrients and acceptable ammonium sorption.

  15. Ammonium sorption from aqueous solutions by the natural zeolite Transcarpathian clinoptilolite studied under dynamic conditions.

    PubMed

    Sprynskyy, Myroslav; Lebedynets, Mariya; Terzyk, Artur P; Kowalczyk, Piotr; Namieśnik, Jacek; Buszewski, Bogusław

    2005-04-15

    The scope of this study is ammonium-ion uptake from synthetic aqueous solutions onto raw and pretreated forms of the natural zeolite Transcarpathian clinoptilolite under dynamic conditions. Hydrogen ions displaced exchangeable cations on the clinoptilolite in distilled water (sodium ions) and hydrochloric acid (sodium, potassium, and calcium ions) and destroyed the zeolite framework structure in the last case. Ammonium uptake onto the zeolite occurs by exchange with Na(+), Ca(2+), and K(+) ions. Although Na(+) ions were observed to be more easily exchanged for both hydrogen and ammonium ions, the role of Ca(2+) ions increased with zeolite saturation by NH(+)(4) ions. The maximum sorption capacity of the clinoptilolite toward NH(+)(4) ions, estimated under dynamic conditions, is significantly higher than that measured under static conditions; proximity of the values of a distribution coefficient and a retardation factor for different conditions (215-265 dm(3)/kg and 979-1107, respectively) allows us to use these parameters to model ammonium uptake onto the clinoptilolite. Slowing down or interruption in filtration resulted in the improvement of ammonium sorption properties of the zeolite. The ammonium removal improves with use of the finer fractions of the clinoptilolite up to 0.35 mm. A recycling study results confirmed the importance of external diffusion for ammonium sorption by the clinoptilolite. Preliminary treatment of the sorbent confirmed the predominant importance of the ion-exchange mechanism. The advantage of prior NaCl treatment of the clinoptilolite in improvement of ammonium removal over the other techniques was shown.

  16. Laboratory column study for evaluating a multimedia permeable reactive barrier for the remediation of ammonium contaminated groundwater.

    PubMed

    Kong, Xiangke; Bi, Erping; Liu, Fei; Huang, Guoxin; Ma, Jianfei

    2015-01-01

    In order to remediate ammonium contaminated groundwater, an innovative multimedia permeable reactive barrier (M-PRB) was proposed, which consisted of sequential columns combining oxygen releasing compound (ORC), zeolite, spongy iron and pine bark in the laboratory scale. Results showed that both ammonium and nitrate could be reduced to levels below the regulatory discharge limits through ion exchange and microbial degradation (nitrification and denitrification) in different compartments of the M-PRB system. The concentration of dissolved oxygen (DO) increased from 2 to above 20 mg/L after the simulated groundwater flowed through the oxygen releasing column packed with ORC, demonstrating that ORC could supply sufficient oxygen for subsequent microbial nitrification. Ammonium was efficiently removed from about 10 to below 0.5 mg N/L in the aerobic reaction column which was filled with biological zeolite. After 54 operating days, more than 70% ammonium could be removed by microbial nitrification in the aerobic reaction column, indicating that the combined use of ion exchange and nitrification by biological zeolite could ensure high and sustainable ammonium removal efficiency. To avoid the second pollution of nitrate produced by the former nitrification, spongy iron and pine bark were used to remove oxygen and supply organic carbon for heterotrophic denitrification in the oxygen removal column and anaerobic reaction column separately. The concentration of nitrate decreased from 14 to below 5 mg N/L through spongy iron-based chemical reduction and microbial denitrification.

  17. Regulating the Skin Permeation Rate of Escitalopram by Ion-pair Formation with Organic Acids.

    PubMed

    Song, Tian; Quan, Peng; Xiang, Rongwu; Fang, Liang

    2016-12-01

    In order to regulate the skin permeation rate (flux) of escitalopram (ESP), ion-pair strategy was used in our work. Five organic acids with different physicochemical properties, benzoic acid (BA), ibuprofen (IB), salicylic acid (SA), benzenesulfonic acid (BSA), and p-aminobenzoic acid (PABA), were employed as counter-ions to regulate the permeation rate of ESP across the rabbit abdominal skin in vitro. The interaction between ESP and organic acids was characterized by FTIR and (13)C NMR spectroscopy. Results showed that all organic acids investigated in this study performed a controlling effect on ESP flux. To further analyze the factors concerned with the permeation capability of ESP-acid complex, a multiple linear regression model was used. It is concluded that the steady-state flux (J) of ESP-acid complexes had a positive correlation with log K o/w (the n-octanol/water partition coefficient of ion-pair complex) and pK a (the acidity of organic acid counter-ion), but a negative correlation with MW (the molecular weight of ion-pair complex). The logK o/w of ion-pair complex is the primary one in all the factors that influence the skin permeation rate of ESP. The results demonstrated that organic acid with appropriate physicochemical properties can be considered as suitable candidate for the transdermal drug delivery of escitalopram.

  18. Ammonium dichromate poisoning: A rare cause of acute kidney injury.

    PubMed

    Radhakrishnan, H; Gopi, M; Arumugam, A

    2014-11-01

    Ammonium dichromate is an inorganic compound frequently used in screen and color printing. Being a strong oxidizing agent, it causes oxygen free radical injury resulting in organ failure. We report a 25-year-old female who presented with acute kidney injury after consumption of ammonium dichromate. She was managed successfully with hemodialysis and supportive measures. This case is reported to highlight the toxicity of ammonium dichromate.

  19. Self-organized microstructures induced by MeV ion beam on silicon surface

    NASA Astrophysics Data System (ADS)

    Ahmad, Muthanna

    2017-02-01

    Micro patterning of self organized structure on silicon surface is induced by ion implantation of energetic (MeV) copper ions. This work reports for the first time the ability of using energetic ions for producing highly ordered ripples and dots of micro sizes. The experiments are realized at the Tandem ion beam accelerator (3 MV) at the IBA laboratory of the Atomic Energy Commission of Syria. Similarly to nano patterning formed by slow ions, the formation of micro patterned structures dots and ripples is observed to be depending on the angle of ion beam incidence, energy and ion fluence. The observation of such microstructures formation is limited to a range of ion energies (few MeV) at fluence higher than 1.75 × 1017 ion cm‑2. The patterned surface layer is completely amorphousized by the ion implantation. Shadowing effect is observed in the formation of microripples and superstructures in the top of ripples. The superstructure develops new morphology that is not observed before. This morphology has butterfly shape with symmetry in its structure.

  20. Extraction of benzene and naphthalene carboxylic acids using quaternary ammonium salts as a model study for the separation of coal oxidation products

    SciTech Connect

    Kawamura, K.; Nagano, H.; Okuwaki, A.

    2005-07-01

    The ion-pair solvent extraction of benzene- and naphthalene-carboxylic acids has been investigated as a model study for the separation of coal oxidation products, which are formed by treatment with alkaline solutions at high temperatures. It was possible that benzene- and naphthalene-dicarboxylic acids are extracted into several types of organic solvents with quaternary ammonium ions. The extraction equilibrium constants (K{sub ex}) for benzoic acid, 1,2-benzenedicarboxylic acid, 1,3-benzenedicarboxylic acid, 1-naphthoic acid, 2-naphthoic acid, 2,3-naphthalenedicarboxylic acid, and 2,6-naphthalenedicarboxylic acid into chloroform were determined at 20{sup o}C. The difference of K{sub ex} among the aromatic acids was sufficiently large for designing a separation method for these aromatic acids. It was unexpected that the extraction of dicarboxylic acids was slower than that of monocarboxylic acids, although the ion-pair formation of aromatic carboxylate ion with quaternary ammonium ion is normally considered as a diffusion control reaction in aqueous phase. Thus, this fact suggests that the phase transfer of the ion-pair from aqueous to organic phase is the rate-determining step. Liner-free-energy relationship was observed for the monocarboxylic acids using different quaternary ammonium salts while that was ambiguous for the dicarboxylic acids. This is due to the steric influence of the counter ions for the magnitude of K{sub ex}.

  1. Determining time-weighted average concentrations of nitrate and ammonium in freshwaters using DGT with ion exchange membrane-based binding layers.

    PubMed

    Huang, Jianyin; Bennett, William W; Welsh, David T; Teasdale, Peter R

    2016-12-08

    Commercially-available AMI-7001 anion exchange and CMI-7000 cation exchange membranes were utilised as binding layers for DGT measurements of NO3-N and NH4-N in freshwaters. These ion exchange membranes are easier to prepare and handle than DGT binding layers consisting of hydrogels cast with ion exchange resins. The membranes showed good uptake and elution efficiencies for both NO3-N and NH4-N. The membrane-based DGTs are suitable for pH 3.5-8.5 and ionic strength ranges (0.0001-0.014 and 0.0003-0.012 mol L(-1) as NaCl for the AMI-7001 and CMI-7000 membrane, respectively) typical of most natural freshwaters. The binding membranes had high intrinsic binding capacities for NO3-N and NH4-N of 911 ± 88 μg and 3512 ± 51 μg, respectively. Interferences from the major competing ions for membrane-based DGTs are similar to DGTs employing resin-based binding layers but with slightly different selectivity. This different selectivity means that the two DGT types can be used in different types of freshwaters. The laboratory and field experiments demonstrated that AMI-DGT and CMI-DGT can be an alternative to A520E-DGT and PrCH-DGT for measuring NO3-N and NH4-N, respectively, as (i) membrane-based DGT have a consistent composition, (ii) avoid the use of toxic chemicals, (iii) provided highly representative results (CDGT : CSOLN between 0.81 and 1.3), and (iv) agreed with resin-based DGTs to within 85-120%.

  2. Ion funnel augmented Mars atmospheric pressure photoionization mass spectrometry for in situ detection of organic molecules.

    PubMed

    Johnson, Paul V; Hodyss, Robert; Beauchamp, J L

    2014-11-01

    Laser desorption is an attractive technique for in situ sampling of organics on Mars given its relative simplicity. We demonstrate that under simulated Martian conditions (~2.5 Torr CO(2)) laser desorption of neutral species (e.g., polycyclic aromatic hydrocarbons), followed by ionization with a simple ultraviolet light source such as a discharge lamp, offers an effective means of sampling organics for detection and identification with a mass spectrometer. An electrodynamic ion funnel is employed to provide efficient ion collection in the ambient Martian environment. This experimental methodology enables in situ sampling of Martian organics with minimal complexity and maximum flexibility.

  3. Secondary ion counting for surface-sensitive chemical analysis of organic compounds using time-of-flight secondary ion mass spectroscopy with cluster ion impact ionization

    SciTech Connect

    Hirata, K.; Saitoh, Y.; Chiba, A.; Yamada, K.; Takahashi, Y.; Narumi, K.

    2011-03-15

    We report suitable secondary ion (SI) counting for surface-sensitive chemical analysis of organic compounds using time-of-flight (TOF) SI mass spectroscopy, based on considerably higher emission yields of SIs induced by cluster ion impact ionization. A SI counting system for a TOF SI mass spectrometer was developed using a fast digital storage oscilloscope, which allows us to perform various types of analysis as all the signal pulses constituting TOF SI mass spectra can be recorded digitally in the system. Effects of the SI counting strategy on SI mass spectra were investigated for C{sub 8} and C{sub 60} cluster ion impacts on an organically contaminated silicon wafer and on polytetrafluoroethylene targets by comparing TOF SI mass spectra obtained from the same recorded signals with different SI counting procedures. Our results show that the use of a counting system, which can cope with high SI yields, is necessary for quantitative analysis of SI mass spectra obtained under high SI yield per impact conditions, including the case of cluster ion impacts on organic compounds.

  4. Ion exchange membranes as novel passive sampling material for organic ions: application for the determination of freely dissolved concentrations.

    PubMed

    Oemisch, Luise; Goss, Kai-Uwe; Endo, Satoshi

    2014-11-28

    Many studies in pharmacology, toxicology and environmental science require a method for determining the freely dissolved concentration of a target substance. A recently developed tool for this purpose is equilibrium passive sampling with polymeric materials. However, this method has rarely been applied to ionic organic substances, primarily due to limited availability of convenient sorption materials. This study introduces ion exchange membranes (IEMs) as a novel passive sampling material for organic ions. The partitioning of 4-ethylbenzene-1-sulfonate, 2,4-dichlorophenoxyacetic acid and pentachlorophenol to one anion exchange membrane (FAS) and of difenzoquat, nicotine and verapamil to one cation exchange membrane (FKS) was investigated. All test substances exhibited a sufficiently high affinity for the respective IEM with logarithmic IEM-water partition coefficients >2.3. Sorption equilibrium was established quickly, within several hours for the FAS membrane and within 1-3 days for the FKS membrane. For permanently charged substances the partitioning to the IEMs was independent of pH, but was influenced by the salt composition of the test solution. For all test substances sorption to IEM was dependent on the substance concentration. Bovine serum albumin-water partition coefficients determined by passive sampling with IEMs agree well with those determined by the conventional dialysis method. The results of this study indicate that IEMs exhibit the potential to measure freely dissolved concentrations of organic ions in a simple and time-saving manner.

  5. Effects of the spaces available for cations in strongly acidic cation-exchange resins on the exchange equilibria by quaternary ammonium ions and on the hydration states of metal ions.

    PubMed

    Watanabe, Yuuya; Ohnaka, Kenji; Fujita, Saki; Kishi, Midori; Yuchi, Akio

    2011-10-01

    The spaces (voids) available for cations in the five exchange resins with varying exchange capacities and cross-linking degrees were estimated, on the basis of the additivity of molar volumes of the constituents. Tetraalkylammonium ions (NR(4)(+); R: Me, Et, Pr) may completely exchange potassium ion on the resin having a larger void radius. In contrast, the ratio of saturated adsorption capacity to exchange capacity of the resin having a smaller void radius decreased with an increase in size of NR(4)(+) ions, due to the interionic contacts. Alkali metal ions could be exchanged quantitatively. While the hydration numbers of K(+), Rb(+), and Cs(+) were independent of the void radius, those of Li(+) and Na(+), especially Na(+), decreased with a decrease in void radius. Interionic contacts between the hydrated ions enhance the dehydration. Multivalent metal ions have the hydration numbers, comparable to or rather greater than those in water. A greater void volume available due to exchange stoichiometry released the interionic contacts and occasionally promoted the involvement of water molecules other than directly bound molecules. The close proximity between ions in the conventional ion-exchange resins having higher exchange capacities may induce varying interactions.

  6. Effects of pH adjustment and sodium ions on sour taste intensity of organic acids.

    PubMed

    Neta, E R D; Johanningsmeier, S D; Drake, M A; McFeeters, R F

    2009-01-01

    Protonated organic acid species have been shown to be the primary stimuli responsible for sour taste of organic acids. However, we have observed that sour taste may be modulated when the pH of acid solutions is raised using sodium hydroxide. Objectives were to evaluate the effect of pH adjustment on sour taste of equimolar protonated organic acid solutions and to investigate the potential roles of organic anions and sodium ions on sour taste perception. Despite equal concentrations of protonated acid species, sour taste intensity decreased significantly with increased pH for acetic, lactic, malic, and citric acids (P < 0.05). Total organic anion concentration did not explain the suppression of sour taste in solutions containing a blend of 3 organic acids with constant concentration of protonated organic acid species and hydrogen ions and variable organic anion concentrations (R(2)= 0.480, P = 0.12). Sour taste suppression in these solutions seemed to be more closely related to sodium ions added in the form of NaOH (R(2)= 0.861, P = 0.007). Addition of 20 mM NaCl to acid solutions resulted in significant suppression of sour taste (P = 0.016). However, sour taste did not decrease with further addition of NaCl up to 80 mM. Presence of sodium ions was clearly shown to decrease sour taste of organic acid solutions. Nonetheless, suppression of sour taste in pH adjusted single acid solutions was greater than what would be expected based on the sodium ion concentration alone, indicating an additional suppression mechanism may be involved.

  7. 70. INTERIOR VIEW OF AMMONIUM NITRATE HOUSE, LOOKING AT AMMONIUM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    70. INTERIOR VIEW OF AMMONIUM NITRATE HOUSE, LOOKING AT AMMONIUM NITRATE IN STORAGE. APRIL 18, 1919. - United States Nitrate Plant No. 2, Reservation Road, Muscle Shoals, Muscle Shoals, Colbert County, AL

  8. Characterization of inclusion complexes of organic ions with hydrophilic hosts by ion transfer voltammetry with solvent polymeric membranes.

    PubMed

    Olmos, José Manuel; Laborda, Eduardo; Ortuño, Joaquín Ángel; Molina, Ángela

    2017-03-01

    The quantitative characterization of inclusion complexes formed in aqueous phase between organic ions and hydrophilic hosts by ion-transfer voltammetry with solvent polymeric membrane ion sensors is studied, both in a theoretical and experimental way. Simple analytical solutions are presented for the determination of the binding constant of the complex from the variation with the host concentration of the electrochemical signal. These solutions are valid for any voltammetric technique and for solvent polymeric membrane ion sensors comprising one polarisable interface (1PI) and also, for the first time, two polarisable interfaces (2PIs). Suitable experimental conditions and data analysis procedures are discussed and applied to the study of the interactions of a common ionic liquid cation (1-octyl-3-metyl-imidazolium) and an ionisable drug (clomipramine) with two hydrophilic cyclodextrins: α-cyclodextrin and 2-hydroxypropyl-β-cyclodextrin. The experimental study is performed via square wave voltammetry with 2PIs and 1PI solvent polymeric membranes and in both cases the electrochemical experiments enable the detection of inclusion complexes and the determination of the corresponding binding constant.

  9. Glufosinate-ammonium

    Integrated Risk Information System (IRIS)

    Glufosinate - ammonium ; CASRN 77182 - 82 - 2 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarci

  10. Ion conductivity and transport by porous coordination polymers and metal-organic frameworks.

    PubMed

    Horike, Satoshi; Umeyama, Daiki; Kitagawa, Susumu

    2013-11-19

    Ion conduction and transport in solids are both interesting and useful and are found in widely distinct materials, from those in battery-related technologies to those in biological systems. Scientists have approached the synthesis of ion-conductive compounds in a variety of ways, in the areas of organic and inorganic chemistry. Recently, based on their ion-conducting behavior, porous coordination polymers (PCPs) and metal-organic frameworks (MOFs) have been recognized for their easy design and the dynamic behavior of the ionic components in the structures. These PCP/MOFs consist of metal ions (or clusters) and organic ligands structured via coordination bonds. They could have highly concentrated mobile ions with dynamic behavior, and their characteristics have inspired the design of a new class of ion conductors and transporters. In this Account, we describe the state-of-the-art of studies of ion conductivity by PCP/MOFs and nonporous coordination polymers (CPs) and offer future perspectives. PCP/MOF structures tend to have high hydrophilicity and guest-accessible voids, and scientists have reported many water-mediated proton (H(+)) conductivities. Chemical modification of organic ligands can change the hydrated H(+) conductivity over a wide range. On the other hand, the designable structures also permit water-free (anhydrous) H(+) conductivity. The incorporation of protic guests such as imidazole and 1,2,4-triazole into the microchannels of PCP/MOFs promotes the dynamic motion of guest molecules, resulting in high H(+) conduction without water. Not only the host-guest systems, but the embedding of protic organic groups on CPs also results in inherent H(+) conductivity. We have observed high H(+) conductivities under anhydrous conditions and in the intermediate temperature region of organic and inorganic conductors. The keys to successful construction are highly mobile ionic species and appropriate intervals of ion-hopping sites in the structures. Lithium (Li

  11. Diagnosis of Trace Toxic Uranium Ions in Organic Liver Cell

    PubMed Central

    Ly, Suw Young; Pack, Eun Chul

    2014-01-01

    Uranium is toxic and radioactive traces of it can be found in natural water and soils. High concentrations of it in biological systems cause genetic disorders and diseases. For the in vivo diagnosis, micro and nano range detection limits are required. Here, an electrochemical assay for trace toxic uranium was searched using stripping voltammetry. Renewable and simplified graphite pencils electrode (PE) was used in a three-electrode cell system. Seawater was used instead of an electrolyte solution. This setup can yield good results and the detection limit was attained to be at 10 μgL−1. The developed skill can be applied to organic liver cell. PMID:25071921

  12. Specific interaction between negative atmospheric ions and organic compounds in atmospheric pressure corona discharge ionization mass spectrometry.

    PubMed

    Sekimoto, Kanako; Sakai, Mami; Takayama, Mitsuo

    2012-06-01

    The interaction between negative atmospheric ions and various types of organic compounds were investigated using atmospheric pressure corona discharge ionization (APCDI) mass spectrometry. Atmospheric negative ions such as O(2)(-), HCO(3)(-), COO(-)(COOH), NO(2)(-), NO(3)(-), and NO(3)(-)(HNO(3)) having different proton affinities served as the reactant ions for analyte ionization in APCDI in negative-ion mode. The individual atmospheric ions specifically ionized aliphatic and aromatic compounds with various functional groups as atmospheric ion adducts and deprotonated analytes. The formation of the atmospheric ion adducts under certain discharge conditions is most likely attributable to the affinity between the analyte and atmospheric ion and the concentration of the atmospheric ion produced under these conditions. The deprotonated analytes, in contrast, were generated from the adducts of the atmospheric ions with higher proton affinity attributable to efficient proton abstraction from the analyte by the atmospheric ion.

  13. Impact of natural organic matter properties on the kinetics of suspended ion exchange process.

    PubMed

    Bazri, Mohammad Mahdi; Mohseni, Madjid

    2016-03-15

    Removal kinetics of four standard organic matter isolates under the application of strongly basic ion exchange resins (IEX) in suspended mode was studied under commercial application conditions. Suwannee River natural organic matter (SRNOM), SR fulvic acid (SRFA), and Pony Lake fulvic acid (PLFA) were greatly removed (>90%) and highly preferred by IEX resins (α > 5, over Cl(-), and HCO3(-)) while SR humic acid (SRHA) was the least preferred organic structure among the four isolates studied (α ≈ 1). Moreover, the efficacy of removal for fulvic acids (i.e., SRFA, PLFA) was consistent over consecutive reuse of IEX resins (i.e., loading cycles) whereas it decreased for SRNOM and SRHA over the course of operation. The stoichiometric correlation between the chloride released from the resins as a result of organic molecules uptake indicated that ion exchange was the dominant mechanism. Results obtained indicated that molecular weight and charge density of isolates played a major role in the performance of ion exchange process for organic matter removal. Furthermore, various empirical and physical models were evaluated using the experimental data and pore diffusion was found to be the rate-liming step during the uptake of organic matters; hence, it was used as the appropriate model to predict the kinetics of removal. Consequently, free liquid diffusivities and effective pore diffusion coefficients of organic molecules were estimated and findings were in agreement with the literature data that were obtained from spectrophotometric methods.

  14. Reactions of organic ions at ambient surfaces in a solvent-free environment.

    PubMed

    Badu-Tawiah, Abraham K; Cyriac, Jobin; Cooks, R Graham

    2012-05-01

    Solvent-free ion/surface chemistry is studied at atmospheric pressure, specifically pyrylium cations, are reacted at ambient surfaces with organic amines to generate pyridinium ions. The dry reagent ions were generated by electrospraying a solution of the organic salt and passing the resulting electrosprayed droplets pneumatically through a heated metal drying tube. The dry ions were then passed through an electric field in air to separate the cations from anions and direct the cations onto a gold substrate coated with an amine. This nontraditional way of manipulating polyatomic ions has provided new chemical insights, for example, the surface reaction involving dry isolated 2,4,6-triphenylpyrylium cations and condensed solid-phase ethanolamine was found to produce the expected N-substituted pyridinium product ion via a pseudobase intermediate in a regiospecific fashion. In solution however, ethanolamine was observed to react through its N-centered and O-centered nucleophilic groups to generate two isomeric products via 2H-pyran intermediates. The O-centered nucleophile reacted less rapidly to give the minor product. The surface reaction product was characterized in situ by surface enhanced Raman spectroscopy, and ex situ using mass spectrometry and H/D exchange, and found to be chemically the same as the major pyridinium solution-phase reaction product.

  15. Characteristics of a heterotrophic nitrogen removal bacterium and its potential application on treatment of ammonium-rich wastewater.

    PubMed

    Zhao, Bin; Tian, Meng; An, Qiang; Ye, Jun; Guo, Jin Song

    2017-02-01

    Nitrogen and organic carbon are major pollutants in wastewater causing environmental problems. Alcaligenes faecalis strain NR, isolated from activated sludge, exhibited the ability to remove ammonium and organic carbon from wastewater simultaneously under sole aerobic conditions in batch culture. Changes in carbon type, C/N ratio, oxygen concentration and inorganic ions significantly affected the treatment efficiency. Furthermore, a continuous bioreactor, solely inoculated with A. faecalis strain NR, was conducted to assess its feasibility for simultaneous nitrogen and organic matter removal in a single aerated reactor. Approximately 66.7-78.3% of NH4(+)-N and 85.8-92.2% of TOC were removed by using synthetic wastewater with 150-200mg/L of NH4(+)-N and 1350-2000mg/L of TOC. This research would be valuable to develop an innovative treatment method for ammonium-rich wastewater under aerobic conditions.

  16. Effects of metal ions on disinfection byproduct formation during chlorination of natural organic matter and surrogates.

    PubMed

    Zhao, Yu; Yang, Hong-wei; Liu, Shi-ting; Tang, Shun; Wang, Xiao-mao; Xie, Yuefeng F

    2016-02-01

    The effects of calcium, cupric, ferrous and ferric ions on the formation of trihalomethanes (THMs) and haloacetic acids (HAAs) were investigated using natural organic matter (NOM), small molecular weight NOM surrogates and natural water samples. The results showed that the effects were greatly dependent on the disinfection byproduct (DBP) precursor structure and molecular weight, and metal ions species. While using NOM as precursors, addition of 4.00 mM calcium ions increased the formation of THMs, dihaloacetic acids (DHAAs) and trihaloacetic acids (THAAs) by 24-47%, 51-61% and 15-25%, respectively. Addition of cupric ions at 0.02 mM increased the formation of THMs and DHAAs by 74-83% and 90-100%, respectively, but decreased the formation of THAAs by 26-27%. Similar effect was not observed when 0.04 mM ferrous or ferric ions were added. The effects of calcium and cupric ions on DBP formation were generally more evident for the NOM surrogates than that for NOM. The primary catalytic effect of calcium ions was due to complexation and less sensitive to molecular structure or weight, while that of cupric ions was attributed to redox reactions and greatly dependent on molecular structure. Both ferric and ferrous iron had substantial effects on the DBP formation of surrogates (citric acid and catechol in particular), which implied that the catalytic effects of ferric and ferrous iron mainly depended on molecular weight. The catalytic effect of cupric ions was also observed on natural water samples, while the effects of calcium, ferrous and ferric ions on natural water samples were not evident.

  17. Phase Diagram of Ammonium Nitrate

    NASA Astrophysics Data System (ADS)

    Dunuwille, Mihindra; Yoo, Choong-Shik

    2013-06-01

    Ammonium Nitrate (AN) has often been subjected to uses in improvised explosive devices, due to its wide availability as a fertilizer and its capability of becoming explosive with slight additions of organic and inorganic compounds. Yet, the origin of enhanced energetic properties of impure AN (or AN mixtures) is neither chemically unique nor well understood - resulting in rather catastrophic disasters in the past1 and thereby a significant burden on safety, in using ammonium nitrates even today. To remedy this situation, we have carried out an extensive study to investigate the phase stability of AN, in different chemical environments, at high pressure and temperature, using diamond anvil cells and micro-Raman spectroscopy. The present results confirm the recently proposed phase IV-to-IV' transition above 15 GPa2 and provide new constraints for the melting and phase diagram of AN to 40 GPa and 673 K. The present study has been supported by the U.S. DHS under Award Number 2008-ST-061-ED0001.

  18. Potential for ion-induced nucleation of volatile organic compounds by radon decay in indoor environments

    SciTech Connect

    Daisey, J.M.

    1991-11-01

    There is considerable interest in the unattached'' fraction of radon progeny in indoor air because of its significance to the estimation of the risks of radon exposure. Because of its high mobility in air, the unattached fraction is more efficiently deposited in the respiratory tract. Variation in the diameter of the unattached'' fraction and in its diffusion coefficient can be due to clustering of other atmospheric species around the {sup 218}PoO{sub 2}{sup +} ion. The purpose of this study was to investigate the potential for the formation of clusters of vapor phase organic compounds, found in indoor air, around the {sup 218}PoO{sub 2}{sup +} ion and to determine which were most likely to form clusters. A secondary purpose was to provide a compilation of measurements of indoor organic compounds for future experiments and theoretical calculations by the radon research community. The classical charged liquid droplet theory (Thomson equation) was used to estimate the Gibbs free energy of ion-induced nucleation and to provide an indication of the indoor organic compounds most likely to undergo ion-induced nucleation. Forty-four volatile and semi-volatile organic compounds out of the more than 300 which have been reported in indoor air were investigated. Water vapor was included for comparison. The results indicate that there is a potential for the formation of clusters of organic compounds around the {sup 218}PoO{sub 2}{sup +} ion. The compounds with the greatest potential for cluster formation are the volatile oxidized hydrocarbons (e.g., n-butanol, phenol, hexanal, nonanal, benzaldehyde, the ketones and the acetates) and the semi-volatile organic compounds (pentachlorophenol, nicotine, chlordane, chlorpyrifos).

  19. Potential for ion-induced nucleation of volatile organic compounds by radon decay in indoor environments

    SciTech Connect

    Daisey, J.M.

    1991-11-01

    There is considerable interest in the ``unattached`` fraction of radon progeny in indoor air because of its significance to the estimation of the risks of radon exposure. Because of its high mobility in air, the unattached fraction is more efficiently deposited in the respiratory tract. Variation in the diameter of the ``unattached`` fraction and in its diffusion coefficient can be due to clustering of other atmospheric species around the {sup 218}PoO{sub 2}{sup +} ion. The purpose of this study was to investigate the potential for the formation of clusters of vapor phase organic compounds, found in indoor air, around the {sup 218}PoO{sub 2}{sup +} ion and to determine which were most likely to form clusters. A secondary purpose was to provide a compilation of measurements of indoor organic compounds for future experiments and theoretical calculations by the radon research community. The classical charged liquid droplet theory (Thomson equation) was used to estimate the Gibbs free energy of ion-induced nucleation and to provide an indication of the indoor organic compounds most likely to undergo ion-induced nucleation. Forty-four volatile and semi-volatile organic compounds out of the more than 300 which have been reported in indoor air were investigated. Water vapor was included for comparison. The results indicate that there is a potential for the formation of clusters of organic compounds around the {sup 218}PoO{sub 2}{sup +} ion. The compounds with the greatest potential for cluster formation are the volatile oxidized hydrocarbons (e.g., n-butanol, phenol, hexanal, nonanal, benzaldehyde, the ketones and the acetates) and the semi-volatile organic compounds (pentachlorophenol, nicotine, chlordane, chlorpyrifos).

  20. Ion irradiation: its relevance to the evolution of complex organics in the outer solar system.

    PubMed

    Strazzulla, G

    1997-01-01

    Ion irradiation of carbon containing ices produces several effects among which the formation of complex molecules and even refractory organic materials whose spectral color and molecular complexity both depend on the amount of deposited energy. Here results from laboratory experiments are summarized. Their relevance for the formation and evolution of simple molecules and complex organic materials on planetary bodies in the external Solar System is outlined.

  1. Turning an organic semiconductor into a low-resistance material by ion implantation.

    PubMed

    Fraboni, Beatrice; Scidà, Alessandra; Cosseddu, Piero; Wang, Yongqiang; Nastasi, Michael; Milita, Silvia; Bonfiglio, Annalisa

    2015-12-01

    We report on the effects of low energy ion implantation on thin films of pentacene, carried out to investigate the efficacy of this process in the fabrication of organic electronic devices. Two different ions, Ne and N, have been implanted and compared, to assess the effects of different reactivity within the hydrocarbon matrix. Strong modification of the electrical conductivity, stable in time, is observed following ion implantation. This effect is significantly larger for N implants (up to six orders of magnitude), which are shown to introduce stable charged species within the hydrocarbon matrix, not only damage as is the case for Ne implants. Fully operational pentacene thin film transistors have also been implanted and we show how a controlled N ion implantation process can induce stable modifications in the threshold voltage, without affecting the device performance.

  2. Turning an organic semiconductor into a low-resistance material by ion implantation

    PubMed Central

    Fraboni, Beatrice; Scidà, Alessandra; Cosseddu, Piero; Wang, Yongqiang; Nastasi, Michael; Milita, Silvia; Bonfiglio, Annalisa

    2015-01-01

    We report on the effects of low energy ion implantation on thin films of pentacene, carried out to investigate the efficacy of this process in the fabrication of organic electronic devices. Two different ions, Ne and N, have been implanted and compared, to assess the effects of different reactivity within the hydrocarbon matrix. Strong modification of the electrical conductivity, stable in time, is observed following ion implantation. This effect is significantly larger for N implants (up to six orders of magnitude), which are shown to introduce stable charged species within the hydrocarbon matrix, not only damage as is the case for Ne implants. Fully operational pentacene thin film transistors have also been implanted and we show how a controlled N ion implantation process can induce stable modifications in the threshold voltage, without affecting the device performance. PMID:27877850

  3. Electrochemical sensing of heavy metal ions with inorganic, organic and bio-materials.

    PubMed

    Cui, Lin; Wu, Jie; Ju, Huangxian

    2015-01-15

    As heavy metal ions severely harm human health, it is important to develop simple, sensitive and accurate methods for their detection in environment and food. Electrochemical detection featured with short analytical time, low power cost, high sensitivity and easy adaptability for in-situ measurement is one of the most developed methods. This review introduces briefly the recent achievements in electrochemical sensing of heavy metal ions with inorganic, organic and bio-materials modified electrodes. In particular, the unique properties of inorganic nanomaterials, organic small molecules or their polymers, enzymes and nucleic acids for detection of heavy metal ions are highlighted. By employing some representative examples, the design and sensing mechanisms of these electrodes are discussed.

  4. Analysis of Supercritical-Extracted Chelated Metal Ions From Mixed Organic-Inorganic Samples

    NASA Technical Reports Server (NTRS)

    Sinha, Mahadeva P. (Inventor)

    1996-01-01

    Organic and inorganic contaminants of an environmental sample are analyzed by the same GC-MS instrument by adding an oxidizing agent to the sample to oxidize metal or metal compounds to form metal ions. The metal ions are converted to chelate complexes and the chelate complexes are extracted into a supercritical fluid such as CO2. The metal chelate extract after flowing through a restrictor tube is directly injected into the ionization chamber of a mass spectrometer, preferably containing a refractory metal filament such as rhenium to fragment the complex to release metal ions which are detected. This provides a fast, economical method for the analysis of metal contaminants in a sample and can be automated. An organic extract of the sample in conventional or supercritical fluid solvents can be detected in the same mass spectrometer, preferably after separation in a supercritical fluid chromatograph.

  5. Partitioning of Organic Ions to Muscle Protein: Experimental Data, Modeling, and Implications for in Vivo Distribution of Organic Ions.

    PubMed

    Henneberger, Luise; Goss, Kai-Uwe; Endo, Satoshi

    2016-07-05

    The in vivo partitioning behavior of ionogenic organic chemicals (IOCs) is of paramount importance for their toxicokinetics and bioaccumulation. Among other proteins, structural proteins including muscle proteins could be an important sorption phase for IOCs, because of their high quantity in the human and other animals' body and their polar nature. Binding data for IOCs to structural proteins are, however, severely limited. Therefore, in this study muscle protein-water partition coefficients (KMP/w) of 51 systematically selected organic anions and cations were determined experimentally. A comparison of the measured KMP/w with bovine serum albumin (BSA)-water partition coefficients showed that anionic chemicals sorb more strongly to BSA than to muscle protein (by up to 3.5 orders of magnitude), while cations sorb similarly to both proteins. Sorption isotherms of selected IOCs to muscle protein are linear (i.e., KMP/w is concentration independent), and KMP/w is only marginally influenced by pH value and salt concentration. Using the obtained data set of KMP/w a polyparameter linear free energy relationship (PP-LFER) model was established. The derived equation fits the data well (R(2) = 0.89, RMSE = 0.29). Finally, it was demonstrated that the in vitro measured KMP/w values of this study have the potential to be used to evaluate tissue-plasma partitioning of IOCs in vivo.

  6. Heterogeneous processes affecting metal ion transport in the presence of organic ligands: Reactive transport modeling

    NASA Astrophysics Data System (ADS)

    Kantar, Cetin

    2007-04-01

    The development of models to accurately simulate metal ion transport through saturated systems under variable chemical conditions, e.g., in systems containing organic ligands (L) such as natural organic matter (NOM), has two essential aspects: (1) establishing the ability to simulate metal ion sorption to aquifer solids over a range of metal/ligand ratios; and (2) to incorporate this ability to simulate metal speciation over a range in chemical conditions (e.g., pH, ligand activity) into mass transport models. Modeling approaches to evaluate metal ion sorption and transport in the presence of NOM include: (1) isotherm-based transport models, and (2) multicomponent (MC) transport models. The accuracy of transport models depends on how well the chemical interactions affecting metal ion transport in the presence of organic ligands (e.g., metal/ligand complexation) are described in transport equations. The isotherm-based transport models often fail to accurately describe metal ion transport in the presence of NOM since these models treat NOM as a single solute despite the fact that NOM is a multicomponent mixture of subcomponents with different chemical and polyfunctional behavior. On the other hand, the calculations presented in this study suggest that a multicomponent reactive transport model, in conjunction with a mechanistic modeling approach for the description of metal ion binding by NOM in a manner conducive to the application of surface complexation modeling (SCM), can effectively be used as an important predictive tool in simulating metal ion sorption and transport under variable chemical conditions in the presence of NOM.

  7. Aqueous phase sensing of cyanide ions using a hydrolytically stable metal-organic framework.

    PubMed

    Karmakar, Avishek; Joarder, Biplab; Mallick, Abhik; Samanta, Partha; Desai, Aamod V; Basu, Sudipta; Ghosh, Sujit K

    2017-01-19

    A pure aqueous phase recognition and corresponding detoxification of highly toxic cyanide ions has been achieved by a fluorescent metal-organic framework (MOF). The cyanide detoxification has been shown to be effective even in in vitro studies and the MOF could be recycled to show the same efficiency of detoxification.

  8. Validation of a Rapid and Sensitive UPLC–MS-MS Method Coupled with Protein Precipitation for the Simultaneous Determination of Seven Pyrethroids in 100 µL of Rat Plasma by Using Ammonium Adduct as Precursor Ion

    PubMed Central

    Singh, Sheelendra Pratap; Dwivedi, Nistha; Raju, Kanumuri Siva Rama; Taneja, Isha; Wahajuddin, Mohammad

    2016-01-01

    United States Environmental Protection Agency has recommended estimating pyrethroids’ risk using cumulative exposure. For cumulative risk assessment, it would be useful to have a bioanalytical method for quantification of one or several pyrethroids simultaneously in a small sample volume to support toxicokinetic studies. Therefore, in the present study, a simple, sensitive and high-throughput ultraperformance liquid chromatography–tandem mass spectrometry method was developed and validated for simultaneous analysis of seven pyrethroids (fenvalerate, fenpropathrin, bifenthrin, lambda-cyhalothrin, cyfluthrin, cypermethrin and deltamethrin) in 100 µL of rat plasma. A simple single-step protein precipitation method was used for the extraction of target compounds. The total chromatographic run time of the method was 5 min. The chromatographic system used a Supelco C18 column and isocratic elution with a mobile phase consisting of methanol and 5 mM ammonium formate in the ratio of 90 : 10 (v/v). Mass spectrometer (API 4000) was operated in multiple reaction monitoring positive-ion mode using the electrospray ionization technique. The calibration curves were linear in the range of 7.8–2,000 ng/mL with correlation coefficients of ≥0.99. All validation parameters such as precision, accuracy, recovery, matrix effect and stability met the acceptance criteria according to the regulatory guidelines. The method was successfully applied to the toxicokinetic study of cypermethrin in rats. To the best of our knowledge, this is the first LC–MS-MS method for the simultaneous analysis of pyrethroids in rat plasma. This validated method with minimal modification can also be utilized for forensic and clinical toxicological applications due to its simplicity, sensitivity and rapidity. PMID:26801239

  9. Validation of a Rapid and Sensitive UPLC-MS-MS Method Coupled with Protein Precipitation for the Simultaneous Determination of Seven Pyrethroids in 100 µL of Rat Plasma by Using Ammonium Adduct as Precursor Ion.

    PubMed

    Singh, Sheelendra Pratap; Dwivedi, Nistha; Raju, Kanumuri Siva Rama; Taneja, Isha; Wahajuddin, Mohammad

    2016-04-01

    United States Environmental Protection Agency has recommended estimating pyrethroids' risk using cumulative exposure. For cumulative risk assessment, it would be useful to have a bioanalytical method for quantification of one or several pyrethroids simultaneously in a small sample volume to support toxicokinetic studies. Therefore, in the present study, a simple, sensitive and high-throughput ultraperformance liquid chromatography-tandem mass spectrometry method was developed and validated for simultaneous analysis of seven pyrethroids (fenvalerate, fenpropathrin, bifenthrin, lambda-cyhalothrin, cyfluthrin, cypermethrin and deltamethrin) in 100 µL of rat plasma. A simple single-step protein precipitation method was used for the extraction of target compounds. The total chromatographic run time of the method was 5 min. The chromatographic system used a Supelco C18 column and isocratic elution with a mobile phase consisting of methanol and 5 mM ammonium formate in the ratio of 90 : 10 (v/v). Mass spectrometer (API 4000) was operated in multiple reaction monitoring positive-ion mode using the electrospray ionization technique. The calibration curves were linear in the range of 7.8-2,000 ng/mL with correlation coefficients of ≥ 0.99. All validation parameters such as precision, accuracy, recovery, matrix effect and stability met the acceptance criteria according to the regulatory guidelines. The method was successfully applied to the toxicokinetic study of cypermethrin in rats. To the best of our knowledge, this is the first LC-MS-MS method for the simultaneous analysis of pyrethroids in rat plasma. This validated method with minimal modification can also be utilized for forensic and clinical toxicological applications due to its simplicity, sensitivity and rapidity.

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

    PubMed

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

    2015-11-01

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

  11. Evaluation of Pulse Counting for the Mars Organic Mass Analyzer (MOMA) Ion Trap Detection Scheme

    NASA Technical Reports Server (NTRS)

    Van Amerom, Friso H.; Short, Tim; Brinckerhoff, William; Mahaffy, Paul; Kleyner, Igor; Cotter, Robert J.; Pinnick, Veronica; Hoffman, Lars; Danell, Ryan M.; Lyness, Eric I.

    2011-01-01

    The Mars Organic Mass Analyzer is being developed at Goddard Space Flight Center to identify organics and possible biological compounds on Mars. In the process of characterizing mass spectrometer size, weight, and power consumption, the use of pulse counting was considered for ion detection. Pulse counting has advantages over analog-mode amplification of the electron multiplier signal. Some advantages are reduced size of electronic components, low power consumption, ability to remotely characterize detector performance, and avoidance of analog circuit noise. The use of pulse counting as a detection method with ion trap instruments is relatively rare. However, with the recent development of high performance electrical components, this detection method is quite suitable and can demonstrate significant advantages over analog methods. Methods A prototype quadrupole ion trap mass spectrometer with an internal electron ionization source was used as a test setup to develop and evaluate the pulse-counting method. The anode signal from the electron multiplier was preamplified. The an1plified signal was fed into a fast comparator for pulse-level discrimination. The output of the comparator was fed directly into a Xilinx FPGA development board. Verilog HDL software was written to bin the counts at user-selectable intervals. This system was able to count pulses at rates in the GHz range. The stored ion count nun1ber per bin was transferred to custom ion trap control software. Pulse-counting mass spectra were compared with mass spectra obtained using the standard analog-mode ion detection. Prelin1inary Data Preliminary mass spectra have been obtained for both analog mode and pulse-counting mode under several sets of instrument operating conditions. Comparison of the spectra revealed better peak shapes for pulse-counting mode. Noise levels are as good as, or better than, analog-mode detection noise levels. To artificially force ion pile-up conditions, the ion trap was overfilled

  12. Engineering-scale destruction of organics at Savannah River Site using the silver(II) ion

    SciTech Connect

    Fleischman, S.D.; Pierce, R.A.

    1991-09-04

    Electrochemical destruction of organics to carbon dioxide, water, and inorganic salts using the silver(II) ion as an oxidizer has been demonstrated at the Savannah River Site (SRS) on a laboratory scale. An engineering-scale facility has been constructed at SRS for a process demonstration of the technology using benzene. Organic destruction rates, cell efficiencies and off gas generation will be related to key process variables. Electrocell design, peripheral support equipment, engineering considerations, safety issues, and operating parameters will be discussed. Future test plans and the impact of early results on the direction of the organics destruction program at SRS will also be addressed.

  13. Identification and quantification of volatile organic compounds using systematic single-ion chromatograms

    SciTech Connect

    Tsuchiya, Yoshio; Kanabus-Kaminska, J.M.

    1996-12-31

    In order to determine the background level of volatile organic compounds (VOCs) in Canadian indoor air, a method of identification and quantification at a level of 0.3 {micro}g/m{sup 3} using systematic single-ion chromatograms (SICs) has been developed. The compounds selected for measurement included several halogenated compounds, oxygen compounds, terpenes, and C8 to C16 n-alkanes. Air samples were taken in 3-layered sorbent tubes and trapped compounds were thermally desorbed into the helium stream of a gas chromatograph/mass spectrometer (GC/MS) analytical system. Total quantities of volatile organic compounds (TVOCs) were measured using a flame ionization detector (FID). Individual compounds were analyzed by a GC/MS. For the identification of compounds in the main stream GC effluent, both the specific GC retention and mass spectra were used. About 50 selected SICs were routinely extracted from a total ion chromatogram (TIC) to detect and quantify compounds. For each compound, a single representative ion was selected. The specific retention was calculated from the elution time on the SIC. For quantification, ion counts under a peak in the SIC were measured. The single-ion MS response factor for some of the compounds was experimentally determined using a dynamic reference procedure.

  14. Preliminary evaluation of an SF5+ polyatomic primary ion beam for analysis of organic thin films by secondary ion mass spectrometry.

    PubMed

    Gillen, G; Roberson, S

    1998-01-01

    Organic vapor deposited thin films of pure biomolecules, polymer films and biomolecules dispersed in gelatin and biological tissue have been analyzed in a magnetic sector secondary ion mass spectrometer using an SF5+ primary ion beam at keV impact energies. In comparison to Ar+ bombardment under identical conditions, bombardment with SF5+ gives a 10 to 50 fold enhancement in the secondary ion yields for characteristic molecular ions. The SF5+ primary ion beam can be focussed to a small spot allowing molecular ion images to be obtained at micrometer spatial resolution with enhanced sensitivity. More importantly, the decay in molecular ion signal as a function of primary ion dose commonly observed in SIMS using monoatomic primary ions is either eliminated or greatly reduced, allowing molecular depth profiles to be obtained of organic thin films. By continuing to sample intact molecules as sputtering proceeds into the sample, the total number of detected characteristic secondary ions is increased by as much as a factor of approximately 700 for SF5+ bombardment as compared to Ar+ bombardment under identical analytical conditions. This effect is thought to be a result of the high erosion rate and the low penetration depth inherent in the use of a polyatomic primary projectile.

  15. Self-assembled organic nanowires for high power density lithium ion batteries.

    PubMed

    Luo, Chao; Huang, Ruiming; Kevorkyants, Ruslan; Pavanello, Michele; He, Huixin; Wang, Chunsheng

    2014-03-12

    The electroactive organic materials are promising alternatives to inorganic electrode materials for the new generation of green Li-ion batteries due to their sustainability, environmental benignity, and low cost. Croconic acid disodium salt (CADS) was used as Li-ion battery electrode, and CADS organic wires with different diameters were fabricated through a facile synthetic route using antisolvent crystallization method to overcome the challenges of low electronic conductivity of CADS and lithiation induced strain. The CADS nanowire exhibits much better electrochemical performance than its crystal bulk material and microwire counterpart. CADS nanowire with a diameter of 150 nm delivers a reversible capability of 177 mAh g(-1) at a current density of 0.2 C and retains capacity of 170 mAh g(-1) after 110 charge/discharge cycles. The nanowire structure also remarkably enhances the kinetics of croconic acid disodium salt. The CADS nanowire retains 50% of the 0.1 C capacity even when the current density increases to 6 C. In contrast, the crystal bulk and microwire material completely lose their capacities when the current density merely increases to 2 C. Such a high rate performance of CADS nanowire is attributed to its short ion diffusion pathway and large surface area, which enable fast ion and electron transport in the electrode. The theoretical calculation suggests that lithiation of CADS experiences an ion exchange process. The sodium ions in CADS will be gradually replaced by lithium ions during the lithiation and delithiation of CADS electrode, which is confirmed by inductively coupled plasma test.

  16. Near-complete structural characterization of phosphatidylcholines using electron impact excitation of ions from organics.

    PubMed

    Campbell, J Larry; Baba, Takashi

    2015-06-02

    Although lipids are critical components of many cellular assemblies and biological pathways, accurate descriptions of their molecular structures remain difficult to obtain. Many benchtop characterization methods require arduous and time-consuming procedures, and multiple assays are required whenever a new structural feature is probed. Here, we describe a new mass-spectrometry-based workflow for enhanced structural lipidomics that, in a single experiment, can yield almost complete structural information for a given glycerophospholipid (GPL) species. This includes the lipid's sum (Brutto) composition from the accurate mass measured for the intact lipid ion and the characteristic headgroup fragment, the regioisomer composition from fragment ions unique to the sn-1 and sn-2 positions, and the positions of carbon-carbon double bonds in the lipid acyl chains. Here, lipid ions are fragmented using electron impact excitation of ions from organics (EIEIO)--a technique where the singly charged lipid ions are irradiated by an electron beam, producing diagnostic product ions. We have evaluated this methodology on various lipid standards, as well as on a biological extract, to demonstrate this new method's utility.

  17. Linear Ion Traps in Space: The Mars Organic Molecule Analyzer (MOMA) Instrument and Beyond

    NASA Astrophysics Data System (ADS)

    Arevalo, Ricardo; Brinckerhoff, William; Mahaffy, Paul; van Amerom, Friso; Danell, Ryan; Pinnick, Veronica; Li, Xiang; Hovmand, Lars; Getty, Stephanie; Grubisic, Andrej; Goesmann, Fred; Cottin, Hervé

    2015-11-01

    Historically, quadrupole mass spectrometer (QMS) instruments have been used to explore a wide survey of planetary targets in our solar system, from Venus (Pioneer Venus) to Saturn (Cassini-Huygens). However, linear ion trap (LIT) mass spectrometers have found a niche as smaller, versatile alternatives to traditional quadrupole analyzers.The core astrobiological experiment of ESA’s ExoMars Program is the Mars Organic Molecule Analyzer (MOMA) onboard the ExoMars 2018 rover. The MOMA instrument is centered on a linear (or 2-D) ion trap mass spectrometer. As opposed to 3-D traps, LIT-based instruments accommodate two symmetrical ion injection pathways, enabling two complementary ion sources to be used. In the case of MOMA, these two analytical approaches are laser desorption mass spectrometry (LDMS) at Mars ambient pressures, and traditional gas chromatography mass spectrometry (GCMS). The LIT analyzer employed by MOMA also offers: higher ion capacity compared to a 3-D trap of the same volume; redundant detection subassemblies for extended lifetime; and, a link to heritage QMS designs and assembly logistics. The MOMA engineering test unit (ETU) has demonstrated the detection of organics in the presence of wt.%-levels of perchlorate, effective ion enhancement via stored waveform inverse Fourier transform (SWIFT), and derivation of structural information through tandem mass spectrometry (MS/MS).A more progressive linear ion trap mass spectrometer (LITMS), funded by the NASA ROSES MatISSE Program, is being developed at NASA GSFC and promises to augment the capabilities of the MOMA instrument by way of: an expanded mass range (i.e., 20 - 2000 Da); detection of both positive and negative ions; spatially resolved (<1 mm) characterization of individual rock core layers; and, evolved gas analysis and GCMS with pyrolysis up to 1300° C (enabling breakdown of refractory phases). The Advanced Resolution Organic Molecule Analyzer (AROMA) instrument, being developed through NASA

  18. Evaluation of Surface Damage of Organic Films due to Irradiation with Energetic Ion Beams

    SciTech Connect

    Hada, Masaki; Hontani, Yusaku; Ichiki, Kazuya; Seki, Toshio; Ibuki, Sachi; Ninomiya, Satoshi; Matsuo, Jiro; Aoki, Takaaki

    2011-01-07

    The surface of L-leucine films irradiated with an Ar{sub 5000} cluster ion beam (5 keV) was characterized by using the X-ray reflective (XRR) measurement method, atomic force microscopy (AFM) and ellipsometry. No significant damage was detected on the surface of the L-leucine films irradiated with the Ar cluster ion beam. Therefore, the large cluster-low-energy (about 1 eV/atom) beam would be suitable for low-damage etching of organic materials.

  19. Effects of Ammonium and Non-Ammonium Salt Additions on Methane Oxidation by Methylosinus trichosporium OB3b and Maine Forest Soils.

    PubMed

    King, G M; Schnell, S

    1998-01-01

    Additions of ammonium and non-ammonium salts inhibit atmospheric methane consumption by soil at salt concentrations that do not significantly affect the soil water potential. The response of soils to non-ammonium salts has previously raised questions about the mechanism of ammonium inhibition. Results presented here show that inhibition of methane consumption by non-ammonium salts can be explained in part by ion-exchange reactions: cations desorb ammonium, with the level of desorption varying as a function of both the cation and anion added; differential desorption results in differential inhibition levels. Differences in the extent of inhibition among ammonium salts can also be explained in part by the effects of anions on ammonium exchange. In contrast, only minimal effects of cations and anions are observed in liquid cultures of Methylosinus trichosporium OB3b. The comparable level of inhibition by equinormal concentrations of NH(4)Cl and (NH(4))(2)SO(4) and the insensitivity of salt inhibition to increasing methane concentrations (from 10 to 100 ppm) are of particular interest, since both of these patterns are in contrast to results for soils. The greater inhibition of methane consumption for NH(4)Cl than (NH(4))(2)SO(4) in soils can be attributed to increased ammonium adsorption by sulfate; increasing inhibition by non-ammonium salts with increasing methane concentrations can be attributed to desorbed ammonium and a physiological mechanism proposed previously for pure cultures.

  20. Effects of Ammonium and Non-Ammonium Salt Additions on Methane Oxidation by Methylosinus trichosporium OB3b and Maine Forest Soils†

    PubMed Central

    King, G. M.; Schnell, S.

    1998-01-01

    Additions of ammonium and non-ammonium salts inhibit atmospheric methane consumption by soil at salt concentrations that do not significantly affect the soil water potential. The response of soils to non-ammonium salts has previously raised questions about the mechanism of ammonium inhibition. Results presented here show that inhibition of methane consumption by non-ammonium salts can be explained in part by ion-exchange reactions: cations desorb ammonium, with the level of desorption varying as a function of both the cation and anion added; differential desorption results in differential inhibition levels. Differences in the extent of inhibition among ammonium salts can also be explained in part by the effects of anions on ammonium exchange. In contrast, only minimal effects of cations and anions are observed in liquid cultures of Methylosinus trichosporium OB3b. The comparable level of inhibition by equinormal concentrations of NH4Cl and (NH4)2SO4 and the insensitivity of salt inhibition to increasing methane concentrations (from 10 to 100 ppm) are of particular interest, since both of these patterns are in contrast to results for soils. The greater inhibition of methane consumption for NH4Cl than (NH4)2SO4 in soils can be attributed to increased ammonium adsorption by sulfate; increasing inhibition by non-ammonium salts with increasing methane concentrations can be attributed to desorbed ammonium and a physiological mechanism proposed previously for pure cultures. PMID:16349485

  1. Decomposition of free chlorine with tertiary ammonium.

    PubMed

    Katano, Hajime; Uematsu, Kohei; Tatsumi, Hirosuke; Tsukatani, Toshihide

    2010-01-01

    The reaction of free chlorine with tertiary ammonium or amine compounds in aqueous solution was studied by the amperometry at a rotating Pt-disk electrode. The amperometric method can be applied to follow the concentration of free chlorine (c(Cl)) even in the presence of chloramine species. By addition of mono- and dibutylammonium to the solution containing free chlorine, the step-like decrease in c(Cl) was observed, indicating the rapid formation of the stable chloramine species. By addition of tributylammonium, the c(Cl) was decreased exponentially to nearly zero even if the free chlorine was present initially in excess. The c(Cl)-t curves can be explained by tributylammonium-species-catalyzed decomposition of free chlorine to chloride ion. The catalytic decomposition was observed also with the tertiary-ammonium-based anion-exchange resins. Furthermore, the anion-exchange resins exhibited the decomposition of not only free chlorine but also chloramines in water.

  2. Ammonium chloride poisoning in chronic renal disease

    PubMed Central

    Levene, Donald L.; Knight, Allan

    1974-01-01

    A 58-year-old woman with a long history of renal stone disease and urinary tract infection presented to the emergency room with exhaustion and air hunger. Laboratory data confirmed profound metabolic acidosis. Unduly large quantities of bicarbonate and potassium were required for correction of the deficits. She had been taking 6 g daily of ammonium chloride as a urine-acidifying agent for a period of six months in addition to agents directed against urinary tract infection. The combination of impaired renal function and effective hydrogen ion loading resulted in profound systemic acidosis. The metabolic derangements associated with the administration of ammonium chloride and its use as a therapeutic agent are discussed. PMID:4850503

  3. Ammonium imidazolium dichromate.

    PubMed

    Zhu, Run-Qiang

    2012-04-01

    In the crystal structure of the title compound, (C(3)H(5)N(2))(NH(4))[Cr(2)O(7)], the anions and cations are linked through N-H⋯O hydrogen bonds, resulting in a three-dimensional structure which contains three kinds of layers parallel to (001). One layer contains imidazole cations, the other two layers the ammonium cations and dichromate anions. The dichromate anion has an eclipsed conformation with a dihedral angle of 14.65 (18)° between the mean planes of the O-P-O-P-O backbone.

  4. A field measurement based scaling approach for quantification of major ions, organic carbon, and elemental carbon using a single particle aerosol mass spectrometer

    NASA Astrophysics Data System (ADS)

    Zhou, Yang; Huang, X. H. Hilda; Griffith, Stephen M.; Li, Mei; Li, Lei; Zhou, Zhen; Wu, Cheng; Meng, Junwang; Chan, Chak K.; Louie, Peter K. K.; Yu, Jian Zhen

    2016-10-01

    Single Particle Aerosol Mass Spectrometers (SPAMS) have been increasingly deployed for aerosol studies in Asia. To date, SPAMS is most often used to provide unscaled information for both the size and chemical composition of individual particles. The instrument's lack of accuracy is primarily due to only a fraction of particles being detected after collection, and the instrumental sensitivity is un-calibrated for various chemical species in mixed ambient aerosols. During a campaign from January to April 2013 at a coastal site in Hong Kong, the particle number information and ion intensity of major PM2.5 components collected by SPAMS were scaled by comparing with collocated bulk PM2.5 measurements of hourly or higher resolution. The bulk measurements include PM2.5 mass by a SHARP 5030 Monitor, major ions by a Monitor for Aerosols & Gases in ambient Air (MARGA), and organic carbon (OC) and elemental carbon (EC) by a Sunset OCEC analyzer. During the data processing, both transmission efficiency (scaled with the Scanning Mobility Particle Sizer) and hit efficiency conversion were considered, and component ion intensities quantified as peak area (PA) and relative peak area (RPA) were analyzed to track the performance. The comparison between the scaled particle mass assuming a particle density of 1.9 g cm-3 from SPAMS and PM2.5 concentration showed good correlation (R2 = 0.81) with a slope of 0.814 ± 0.004. Regression analysis results suggest an improved scaling performance using RPA compared with PA for most of the major PM2.5 components, including sulfate, nitrate, potassium, ammonium, OC and EC. Thus, we recommend preferentially scaling these species using the RPA. For periods of high K+ concentrations (>1.5 μg m-3), under-estimation of K+ by SPAMS was observed due to exceeding the dynamic range of the acquisition board. When only applying the hit efficiency correction, data for sulfate, nitrate, ammonium, potassium and OC were in reasonably good correlation (R2 = 0

  5. A selected ion flow tube study of the reactions of NO + and O + 2 ions with some organic molecules: The potential for trace gas analysis of air

    NASA Astrophysics Data System (ADS)

    Španěl, Patrik; Smith, David

    1996-02-01

    A study has been carried out using our selected ion flow tube apparatus of the reactions of NO+ and O+2 ions in their vibronic ground states with ten organic species: the hydrocarbons, benzene, toluene, isoprene, cyclopropane, and n-pentane; the oxygen-containing organics, methanol, ethanol, acetaldehyde, acetone, and diethyl ether. The major objectives of this work are, on the one hand, to fully understand the processes involved in these reactions and, on the other hand, to explore the potential of NO+ and O+2 as chemical ionization agents for the analysis of trace gases in air and on human breath. Amongst the NO+ reactions, charge transfer, hydride-ion transfer, and termolecular association occur, and the measured rate coefficients, k, for the reactions vary from immeasurably small to the maximum value, collisional rate coefficient, kc. The O+2 reactions are all fast, in each case the k being equal to or an appreciable fraction of kc, and charge transfer producing the parent organic ion or dissociative charge transfer resulting in two or three fragments of the parent ion are the reaction processes that occur. We conclude from these studies, and from previous studies, that NO+ ions and O+2 ions can be used to great effect as chemical ionization agents for trace gas analysis, especially in combination with H3O+ ions which we now routinely use for this purpose.

  6. Hydrothermal synthesis of ammonium illite

    USGS Publications Warehouse

    Sucha, V.; Elsass, F.; Eberl, D.D.; Kuchta, L'.; Madejova, J.; Gates, W.P.; Komadel, P.

    1998-01-01

    Synthetic gel and glass of illitic composition, natural kaolinite, and mixed-layer illite-smectite were used as starting materials for hydrothermal synthesis of ammonium illite. Ammonium illite was prepared from synthetic gel by hydrothermal treatment at 300??C. The onset of crystallization began within 3 h, and well-crystallized ammonium illite appeared at 24 h. Increasing reaction time (up to four weeks) led to many illite layers per crystal. In the presence of equivalent proportions of potassium and ammonium, the gel was transformed to illite with equimolar contents of K and NH4. In contrast, synthesis using glass under the same conditions resulted in a mixture of mixed-layer ammonium illite-smectite with large expandability and discrete illite. Hydrothermal treatments of the fine fractions of natural kaolinite and illite-smectite produced ammonium illite from kaolinite but the illite-smectite remained unchanged.

  7. [Study of the response characteristics of PVC membrane ion-associate type electrodes for organic base cations].

    PubMed

    Kang, X J; Wang, C Y

    1990-01-01

    A new type of ISEs which only uses alkaloid precipitants in place of ion pairs as active materials in polyvinyl chloride was recommended. The characteristics of the electrodes sensing over ten kinds of organic bases have been studied in comparison with those based on ion pairs. It can be concluded that the response characteristics of ion-associate type ISEs depend on the strength of the association between ion-exchange site and principal ions. Visual turbidimetry was used to select active materials for ISEs in advance. Among six alkaloid precipitants (silicotungstic acid, tetraphenyl borate, dipicrylamine, picric acid, picrolonic acid and Reineckate), silicotungstic acid is the most active material for ion-associate type organic base cation ISEs. With it, the sensor has wider Nernst linearity and lower detection limit than some ion pair based ones in literature.

  8. Removal of ammonium from municipal landfill leachate using natural zeolites.

    PubMed

    Ye, Zhihong; Wang, Jiawen; Sun, Lingyu; Zhang, Daobin; Zhang, Hui

    2015-01-01

    Ammonium ion-exchange performance of the natural zeolite was investigated in both batch and column studies. The effects of zeolite dosage, contact time, stirring speed and pH on ammonium removal were investigated in batch experiments. The result showed that ammonium removal efficiency increased with an increase in zeolite dosage from 25 to 150 g/L, and an increase in stirring speed from 200 to 250 r/min. But further increase in zeolite dosage and stirring speed would result in an unpronounced increase of ammonium removal. The optimal pH for the removal of ammonium was found as 7.1. In the column studies, the effect of flow rate was investigated, and the total ammonium removal percentage during 180 min operation time decreased with the flow rate though the ion-exchange capacity varied to a very small extent with the flow rate ranging from 4 to 9 mL/min. The spent zeolite was regenerated by sodium chloride solution and the ammonia removal capacity of zeolite changed little or even increased after three regeneration cycles.

  9. Microfabricated ion trap mass spectrometry for characterization of organics and potential biomarkers

    NASA Astrophysics Data System (ADS)

    Austin, Daniel

    Mass spectrometry is a powerful analytical technique with a strong history in planetary exploration, and is the method of choice for detection and identification of organic and biological molecules. MS instrumentation can also be combined with techniques such as gas chromatography, liquid chromatography, or chiral separation, which are particularly important for analysis of complex mixtures or possible homochirality. Ion traps have several inherent advantages, including speed of analysis (important for GC-MS), MS/MS capabilities (important to identification of unknown compounds), excellent sensitivity, and ease of coupling with ambient ionization techniques that are under development for biomolecule detection. We report on progress in using microfabrication techniques to produce radiofrequency quadrupole ion traps that are much smaller, lighter, and lower power than existing instruments. We produce ion traps using an assembly of two ceramic plates, the facing surfaces of which are lithographically patterned with electrodes. This approach allows great flexibility in the trap geometry, and we have demonstrated working mass spectrometers with quadrupole, linear, and toroidal trapping fields. The approach also allows correction of higher-order terms in the electric field. With this system, mass resolution of up to 1300 has been demonstrated, which is adequate for identification of a wide range of potential biomarkers. Capabilities such as tandem analysis have also been demonstrated. Of particular interest is an ion trap that contains both quadrupole and toroidal trapping regions simultaneously and coaxially. Ions can be trapped as a large reservoir in the toroidal region and introduced in small batches to the quadrupole region for mass analysis. This capability is particularly valuable where the sample of interest is very small, such as microfossil with trace organics, and where the organic inventory is both complex and unknown. Development and results of this device

  10. Infrared and Raman spectra of magnesium ammonium phosphate hexahydrate (struvite) and its isomorphous analogues. Part VI: FT-IR spectra of isomorphously isolated species. NH4+ ions isolated in MKPO 4·6H 2O (M = Mg; Ni) and PO43- ions isolated in MgNH 4AsO 4·6H 2O

    NASA Astrophysics Data System (ADS)

    Cahil, A.; Šoptrajanov, B.; Najdoski, M.; Lutz, H. D.; Engelen, B.; Stefov, V.

    2008-03-01

    Examination of mixed crystals, especially those with isomorphously isolated ions, has proved very useful in spectra-structure correlation studies. Room (RT) and low temperature (LNT) FT-IR spectra of ammonium doped in MgKPO 4·6H 2O and NiKPO 4·6H 2O and phosphate doped in MgNH 4AsO 4·6H 2O in different degrees were recorded. All three compounds are isostructural with struvite, MgNH 4PO 4·6H 2O, space group Pmn2 1, forming substitutional mixed crystals with Cs symmetry of the anions. Analysis of the region of ν 4(NH 4), ν 3(PO 4) and ν 4(PO 4) modes of LNT FT-IR difference spectra of analogues with a small content of NH4+ and PO43- revealed the expected decrease of Td symmetry of free NH4+ and PO43- ions to Cs site symmetry. Due to the Cs site symmetry of the anions, the degeneration of the ν 4(NH 4), ν 3PO 4) and ν 4PO 4) modes is raised and, hence, three components are observed in the difference FT-IR spectra. This conclusion can not be derived only from studies of no-doped polycrystalline samples of struvite type compounds.

  11. Membrane permeation process for dehydration of organic liquid mixtures using sulfonated ion-exchange polyalkene membranes

    DOEpatents

    Cabasso, Israel; Korngold, Emmanuel

    1988-01-01

    A membrane permeation process for dehydrating a mixture of organic liquids, such as alcohols or close boiling, heat sensitive mixtures. The process comprises causing a component of the mixture to selectively sorb into one side of sulfonated ion-exchange polyalkene (e.g., polyethylene) membranes and selectively diffuse or flow therethrough, and then desorbing the component into a gas or liquid phase on the other side of the membranes.

  12. Protection by organic ions against DNA damage induced by low energy electrons

    NASA Astrophysics Data System (ADS)

    Dumont, A.; Zheng, Y.; Hunting, D.; Sanche, L.

    2010-01-01

    It is well known that electrons below 15 eV induce strand breaks in DNA essentially via the formation of transient anions which decay by dissociative electron attachment (DEA) or into dissociative electronics states. The present article reports the results of a study on the influence of organic ions on this mechanism. tris and EDTA are incorporated at various concentrations within DNA films of different thicknesses. The amino group of tris molecules and the carboxylic acid function of ethylenediamine tetra-acetic acid (EDTA) molecules together can be taken as simple model for the amino acids components of proteins, such as histones, which are intimately associated with the DNA of eukaryotic cells. The yield of single strand breaks induced by 10 eV electrons is found to decrease dramatically as a function of the number of organic ions/nucleotide. As few as 2 organic ions/nucleotide are sufficient to decrease the yield of single strand breaks by 70%. This effect is partly explained by an increase in multiple inelastic electrons scattering with film thickness but changes in the resonance parameters can also contribute to DNA protection. This can occur if the electron captures cross section and the lifetime of the transient anions (i.e., core-excited resonances) formed at 10 eV are reduced by the presence of organic ions within the grooves of DNA. Moreover, it is proposed that the tris molecules may participate in the repair of DNA anions [such as G(-H)-] induced by DEA on DNA bases.

  13. Modeling dry and wet deposition of sulfate, nitrate, and ammonium ions in Jiuzhaigou National Nature Reserve, China using a source-oriented CMAQ model: Part I. Base case model results.

    PubMed

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

    2015-11-01

    A source-oriented Community Multiscale Air Quality (CMAQ) model driven by the meteorological fields generated by the Weather Research and Forecasting (WRF) model was used to study the dry and wet deposition of nitrate (NO3(-)), sulfate (SO4(2-)), and ammonium (NH4(+)) ions in the Jiuzhaigou National Nature Reserve (JNNR), China from June to August 2010 and to identify the contributions of different emission sectors and source regions that were responsible for the deposition fluxes. The model performance is evaluated in this paper and the source contribution analyses are presented in a companion paper. The results show that WRF is capable of reproducing the observed precipitation rates with a Mean Normalized Gross Error (MNGE) of 8.1%. Predicted wet deposition fluxes of SO4(2-) and NO3(-) at the Long Lake (LL) site (3100 m a.s.l.) during the three-month episode are 2.75 and 0.34 kg S(N) ha(-1), which agree well with the observed wet deposition fluxes of 2.42 and 0.39 kg S(N) ha(-1), respectively. Temporal variations in the weekly deposition fluxes at LL are also well predicted. Wet deposition flux of NH4(+) at LL is over-predicted by approximately a factor of 3 (1.60 kg N ha(-1)vs. 0.56 kg N ha(-1)), likely due to missing alkaline earth cations such as Ca(2+) in the current CMAQ simulations. Predicted wet deposition fluxes are also in general agreement with observations at four Acid Deposition Monitoring Network in East Asia (EANET) sites in western China. Predicted dry deposition fluxes of SO4(2-) (including gas deposition of SO2) and NO3(-) (including gas deposition of HNO3) are 0.12 and 0.12 kg S(N) h a(-1) at LL and 0.07 and 0.08 kg S(N) ha(-1) at Jiuzhaigou Bureau (JB) in JNNR, respectively, which are much lower than the corresponding wet deposition fluxes. Dry deposition flux of NH4(+) (including gas deposition of NH3) is 0.21 kg N ha(-1) at LL, and is also much lower than the predicted wet deposition flux. For both dry and wet deposition fluxes, predictions

  14. Recovering organic matters and ions from wastewater by genetically engineered Bacillus subtilis biomass.

    PubMed

    Zhu, Wei; Liu, Yujie; Cao, Xia; Zhang, Sainan; Wang, Chaoyuan; Lin, Xinli

    2015-09-15

    Water pollution causes substantial damage to the environment and to human health, and the current methods to treat pollution suffer from high cost and low efficiency, resulting in increased environmental damages. Using genetic modification and functional selection, we developed a novel biosorbent from Genetically Engineered Bacillus subtilis (GEBS) cells. At a ratio of biosorbent to direct blue dye of about 1:1.25 in a water solution, the dye pigments can be completely adsorbed in 40 s, decreasing COD to zero. Contrary to other biosorbents, ions such as Fe(2+) and Cu(2+) have significant advantages in terms of the adsorbing efficiency. The GEBS biomass can therefore capture both organics and ions from wastewater simultaneously and achieve co-precipitation in 2-10 min, which are features critical for practical applications of wastewater treatment. In addition, we used six different eluting solutions to regenerate used biomass, all resulting in renewed, highly efficient color and COD elimination capacities, with the best elution solution being NaHCO3 and Na2CO3. For practical applications, we showed a high COD elimination rate when using the GEBS biomass to treat raw water from textile enterprises, paper mill, and petrochemical industries. Compared with currently available adsorbing agents, the GEBS cells can adsorb organic and ion waste much faster and with much higher efficiency, can be regenerated and recycled efficiently, and may have broad applications in treating organic water pollution.

  15. Unraveling the storage mechanism in organic carbonyl electrodes for sodium-ion batteries

    PubMed Central

    Wu, Xiaoyan; Jin, Shifeng; Zhang, Zhizhen; Jiang, Liwei; Mu, Linqin; Hu, Yong-Sheng; Li, Hong; Chen, Xiaolong; Armand, Michel; Chen, Liquan; Huang, Xuejie

    2015-01-01

    Organic carbonyl compounds represent a promising class of electrode materials for secondary batteries; however, the storage mechanism still remains unclear. We take Na2C6H2O4 as an example to unravel the mechanism. It consists of alternating Na-O octahedral inorganic layer and π-stacked benzene organic layer in spatial separation, delivering a high reversible capacity and first coulombic efficiency. The experiment and calculation results reveal that the Na-O inorganic layer provides both Na+ ion transport pathway and storage site, whereas the benzene organic layer provides electron transport pathway and redox center. Our contribution provides a brand-new insight in understanding the storage mechanism in inorganic-organic layered host and opens up a new exciting direction for designing new materials for secondary batteries. PMID:26601260

  16. Potential for ion-induced nucleation of volatile organic compounds by radon decay in indoor environments

    SciTech Connect

    Daisey, J.M. ); Hopke, P.K. )

    1993-07-01

    The theoretical potential for the formation of clusters of vapor-phase organic compounds found in indoor air around the [sup 218]PoO[sub x][sup +] ion was investigated as well as which compounds were most likely to form clusters. A compilation of measurements of indoor organic compounds has been made for future experiments and theoretical calculations by the radon research community. Forty-four volatile and semivolatile organic compounds out of the more than 300 that have been reported in indoor air were investigated. Water vapor was included for comparison. The results indicate that there is a potential for the formation of clusters of organic compounds around the [sup 218]PoO[sub x][sup +] ion. The compounds with the greatest potential for cluster formation are the volatile oxidized hydrocarbons (e.g., n-butanol, phenol, hexanal, nonanal, benzaldehyde, the ketones, and the acetates) and the semivolatile organic compounds (pentachlorophenol, nicotine, chlordane, chlorpyrifos). Although the estimated diameters are consistent with the measured diameters for the unattached fraction, the state of experimental and theoretical knowledge in this area is not sufficiently developed to judge the quantitative validity of these predictions. 48 refs., 1 fig., 5 tabs.

  17. Organic surfaces excited by low-energy ions: atomic collisions, molecular desorption and buckminsterfullerenes.

    PubMed

    Delcorte, Arnaud

    2005-10-07

    This article reviews the recent progress in the understanding of kiloelectronvolt particle interactions with organic solids, including atomic displacements in a light organic medium, vibrational excitation and desorption of fragments and entire molecules. This new insight is the result of a combination of theoretical and experimental approaches, essentially molecular dynamics (MD) simulations and secondary ion mass spectrometry (SIMS). Classical MD simulations provide us with a detailed microscopic view of the processes occurring in the bombarded target, from the collision cascade specifics to the scenarios of molecular emission. Time-of-flight SIMS measures the mass and energy distributions of sputtered ionized fragments and molecular species, a precious source of information concerning their formation, desorption, ionization and delayed unimolecular dissociation in the gas phase. The mechanisms of energy transfer and sputtering are compared for bulk molecular solids, organic overlayers on metal and large molecules embedded in a low-molecular weight matrix. These comparisons help understand some of the beneficial effects of metal substrates and matrices for the analysis of molecules by SIMS. In parallel, I briefly describe the distinct ionization channels of molecules sputtered from organic solids and overlayers. The specific processes induced by polyatomic projectile bombardment, especially fullerenes, are discussed on the basis of new measurements and calculations. Finally, the perspective addresses the state-of-the-art and potential developments in the fields of surface modification and analysis of organic materials by kiloelectronvolt ion beams.

  18. Optimal cultivation of simultaneous ammonium and phosphorus removal aerobic granular sludge in A/O/A sequencing batch reactor and the assessment of functional organisms.

    PubMed

    Zhang, Cuiya; Zhang, Hanmin; Yang, Fenglin

    2014-08-01

    In this study, sequencing batch reactor (SBR) with an anaerobic/aerobic/anoxic operating mode was used to culture granular sludge. Optimal adjustment of cycle duration was achieved by the direction ofpH, oxidation reduction potential and dissolved oxygen parameters. The results showed that the treating efficiency was significantly improved as the cycle was shortened from 450 to 360 min and further to 200 min. Nitrogen and phosphorus removal were nearly quantitative after 50 days operation and maintained stable to the end of the study period. The typical cycle tests revealed that simultaneous denitrification and phosphorus removal occurred when aerobic granules were gradually formed. The nitrite effect tests showed that less than 4.8 mg N/L of the nitrite could enhance superficial specific aerobic phosphate uptake rate (SAPUR) under aerobic condition, indicating that the traditional method to evaluate the capability of total phosphate-accumulating organisms (PAOs) was inaccurate. Additionally, a high level of nitrite was detrimental to PAOs. A novel method was developed to determine the activity of each kind of PAOs and other denitrifying organisms. The results showed that (1) nitrate, besides nitrite, could also enhance SAPUR and (2) aerobic granular sludge could perform denitrification even when phosphate was not supplied under anoxic condition, suggesting that other denitrifying organisms besides denitrifying phosphate-accumulating organisms also contributed to denitrification.

  19. Titanium (IV) ion-modified covalent organic frameworks for specific enrichment of phosphopeptides.

    PubMed

    Wang, Heping; Jiao, Fenglong; Gao, Fangyuan; Lv, Yayao; Wu, Qiong; Zhao, Yan; Shen, Yehua; Zhang, Yangjun; Qian, Xiaohong

    2017-05-01

    To date, plenty of new alternative materials for phosphopeptides enrichment prior to mass spectrometry (MS) analysis appear, especially immobilized metal ion affinity chromatography (IMAC) materials. The variable combinations with different metal ions, chelating ligands and solid supports offer full of optionality for IMAC. However, further improvement was predicted by the tedious and complex synthetic process. In this work, a novel covalent organic framework (COF)-based IMAC material (denoted TpPa-2-Ti(4+)) was prepared simply by direct immobilizing Ti (IV) into TpPa-2 COFs without any extra chelating ligands. The structure and composition of as-prepared composites were confirmed by PXRD, FT-IR and XPS, and a new flower-shaped Ti(4+)-IMAC with regular micro-nano hierarchical structure was observed in the SEM and TEM images. The obtained titanium (IV) ion-modified covalent organic frameworks demonstrated low limit of detection (4 fmol) and largely-satisfactory selectivity (β-casein: BSA=1:100) for phosphopeptide capturing from β-casein. Similarly, 18 and 17 phosphopeptides could be easily detected in the tryptic digest of α-casein or the digest mixture of α-casein and BSA (1:50). They were also successfully applied for enrichment of phosphopeptides from non-fat milk and HeLa cells with high sensitivity and satisfactory selectivity. All above results showed that the new titanium (IV) ion-modified covalent organic framework is expected to be a potential IMAC for phosphopeptide enrichment in large-scale phosphoproteomics studies.

  20. Removal of ion-implanted photoresists on GaAs using two organic solvents in sequence

    NASA Astrophysics Data System (ADS)

    Oh, Eunseok; Na, Jihoon; Lee, Seunghyo; Lim, Sangwoo

    2016-07-01

    Organic solvents can effectively remove photoresists on III-V channels without damage or etching of the channel material during the process. In this study, a two-step sequential photoresist removal process using two different organic solvents was developed to remove implanted ArF and KrF photoresists at room temperature. The effects of organic solvents with either low molar volumes or high affinities for photoresists were evaluated to find a proper combination that can effectively remove high-dose implanted photoresists without damaging GaAs surfaces. The performance of formamide, acetonitrile, nitromethane, and monoethanolamine for the removal of ion-implanted ArF and KrF photoresists were compared using a two-step sequential photoresist removal process followed by treatment in dimethyl sulfoxide (DMSO). Among the various combinations, the acetonitrile + DMSO two-step sequence exhibited the best removal of photoresists that underwent ion implantation at doses of 5 × 1013-5 × 1015 atoms/cm2 on both flat and trench-structured GaAs surfaces. The ability of the two-step process using organic solvents to remove the photoresists can be explained by considering the affinities of solvents for a polymer and its permeability through the photoresist.

  1. Designing self-organized nanopatterns on Si by ion irradiation and metal co-deposition.

    PubMed

    Zhang, K; Bobes, O; Hofsäss, H

    2014-02-28

    Dot and ripple nanopatterns on Si surfaces with defined symmetry and characteristic dot spacings of 50-70 nm were created by 1 keV Ar ion irradiation at normal incidence and simultaneous co-deposition of Fe atoms at grazing incidence. Fe was continuously supplied from different sputter targets surrounding the Si substrate, leading to a steady-state Fe content in the near-surface region of the substrates. The pattern formation is self-organized, most probably caused by ion-induced phase separation. Patterns were analyzed with atomic force microscopy and the Fe content in the irradiated layer was measured with Rutherford backscattering. The symmetries of the produced patterns are isotropic, four-fold symmetric, three-fold symmetric and various types of two-fold symmetric patterns, depending on the geometrical arrangement of the sputter targets. Pattern formation was studied for a steady-state coverage of Fe between 0.5 and 3.3 × 10(15) Fe cm(-2). The threshold coverage for the onset of pattern formation is about 0.5-1 × 10(15) Fe cm(-2). The coherence length of the patterns is comparable to the average dot spacing. Nevertheless, the autocorrelation analysis reveals a residual long-range periodicity of some patterns. The dot spacing can be adjusted between about 20 nm and several hundred nm depending on the ion species and ion energy.

  2. Gas-phase reactions of organic radicals and diradicals with ions.

    PubMed

    Zhang, Xu; Bierbaum, Veronica M; Ellison, G Barney; Kato, Shuji

    2004-02-22

    Reactions of polyatomic organic radicals with gas phase ions have been studied at thermal energy using a flowing afterglow-selected ion flow tube (FA-SIFT) instrument. A supersonic pyrolysis nozzle produces allyl radical (CH2CHCH2) and ortho-benzyne diradical (o-C6H4) for reaction with ions. We have observed: [CH2CHCH2 + H3O+ --> C3H6+ + H2O], [CH2CHCH2 + HO- --> no ion products], [o-C6H4 + H3O+ --> C6H5+ + H2O], and [o-C6H4 + HO- --> C6H3- + H2O]. The proton transfer reactions with H3O+ occur at nearly every collision (kII approximately with 10(-9) cm3 s(-1)). The exothermic proton abstraction for o-C6H4 + HO- is unexpectedly slow (kII approximately with 10(-10) cm3 s(-1)). This has been rationalized by competing associative detachment: o-C6H4 + HO- --> C6H5O + e-. The allyl + HO- reaction proceeds presumably via similar detachment pathways.

  3. Ion Bombardment Experiments Suggesting an Origin for Organic Particles in Pre-Cometary and Cometary Ices

    NASA Technical Reports Server (NTRS)

    Wdowiak, Thomas J.; Robinson, Edward L.; Flickinger, Gregory C.; Boyd, David A.

    1997-01-01

    Simple molecules frozen as mantles of interstellar and circumstellar grains and incorporated into comets are subjected to ion bombardment in the form of cosmic rays, stellar flares, stellar winds, and ions accelerated in stellar wind shocks. The total expected dosage for the variety of situations range from 10 eV/molecule for interplanetary dust subjected to solar flares to 10(exp 6) eV/molecule for material in the T Tauri environment. Utilizing a Van de Graaff accelerator and a target chamber having cryogenic and mass spectrometer capabilities, we have bombarded frozen gases in the temperature range of 10 K to 30 K with 175 keV protons. After irradiation, removal of the ice by sublimation at an elevated temperature in vacuum reveals a fluffy residue. These experiments suggest that processes resulting in the formation of organic particles found in the coma of Comet Halley, "CHON", may have included ion bombardment. Also, the moderate energy (100 keV to 500 keV) shock accelerated ion environment of bipolar outflow of stars in the planetary nebula stage such as the Red Rectangle, could produce complex molecular species which emit the observed unidentified infrared bands at 3.3 micro-m, 6.2 micro-m, 7.7 micro-m, 8.6 micro-m, and 11.3 micro-m.

  4. Silver Ion-Mediated Heterometallic Three-Fold Interpenetrating Uranyl-Organic Framework.

    PubMed

    Mei, Lei; Wu, Qun-yan; An, Shu-wen; Gao, Zeng-qiang; Chai, Zhi-fang; Shi, Wei-qun

    2015-11-16

    A unique case of a uranyl-silver heterometallic 3-fold interpenetrating network (U-Ag-2,6-DCPCA) from a multifunctionalized organic ligand, 2,6-dichloroisonicotinic acid, in the presence of uranyl and silver ions is reported. It is the first report of a heterometallic uranyl-organic interpenetrating network or framework. Notably, a (4,4)-connected uranyl building unit in U-Ag-2,6-DCPCA, which is available through combined influences of structural halogenation and silver ion additive on uranyl coordination, plays a vital role in the formation of a 3-fold interpenetrating network. Halogen substitution effectively changes structural features and coordination behaviors of isonicotinate ligand and contributes to the control of uranyl coordination. Meanwhile, it exerts influence on the stabilization of 3-fold interpenetrating networks by halogen-halogen interactions. Theoretical calculation suggests that the silver ion should mainly serve as an inductive factor of uranyl species through strong Ag-N binding affinity, directly leading to the formation of a (4,4)-connected uranyl building unit and finally a heterometallic 3-fold interpenetrating network. Related experimental results, especially an interesting postsynthetic metalation, afford further evidence of this induction effect.

  5. Ion bombardment experiments suggesting an origin for organic particles in pre-cometary and cometary ices

    NASA Technical Reports Server (NTRS)

    Wdowiak, Thomas J.; Robinson, Edward L.; Flickinger, Gregory C.; Boyd, David A.

    1989-01-01

    During the Giotto and Vega encounters with Comet Halley both organic particles called CHON and energetic ions were detected. The acceleration of ions to hundreds of keV in the vicinity of the bow shock and near the nucleus may be a demonstration of a situation occurring in the early solar system (perhaps during the T Tauri stage) that led to the formation of organic particles only now released. Utilizing a Van de Graaff accelerator and a target chamber having cryogenic and mass spectrometer capabilities, frozen gases were bombarded at 10 K with 175 keV protons with the result that fluffy solid material remains after sublimation of the ice. Initial experiments were carried out with a gas mixture in parts of 170 carbon monoxide, 170 argon, 25 water, 20 nitrogen, and 15 methane formulated to reflect an interstellar composition in experiments involving the freezing out of the products of a plasma. The plasma experiments resulted in a varnish-like film residue that exhibited luminescence when excited with ultraviolet radiation, while the ion bombardment created particulate material that was not luminescent.

  6. Organic solvents, electrolytes, and lithium ion cells with good low temperature performance

    NASA Technical Reports Server (NTRS)

    Smart, Marshall C. (Inventor); Bugga, Ratnakumar V. (Inventor); Surampudi, Subbarao (Inventor); Huang, Chen-Kuo (Inventor)

    2002-01-01

    Multi-component organic solvent systems, electrolytes and electrochemical cells characterized by good low temperature performance are provided. In one embodiment, an improved organic solvent system contains a ternary mixture of ethylene carbonate, dimethyl carbonate and diethyl carbonate. In other embodiments, quaternary systems include a fourth component, i.e, an aliphatic ester, an asymmetric alkyl carbonate or a compound of the formula LiOX, where X is R, COOR, or COR, where R is alkyl or fluoroalkyl. Electrolytes based on such organic solvent systems are also provided and contain therein a lithium salt of high ionic mobility, such as LiPF.sub.6. Reversible electrochemical cells, particularly lithium ion cells, are constructed with the improved electrolytes, and preferably include a carbonaceous anode, an insertion type cathode, and an electrolyte interspersed therebetween.

  7. Substrate specificity of Rhbg: ammonium and methyl ammonium transport

    PubMed Central

    Abdulnour-Nakhoul, Solange M.; Boulpaep, Emile L.; Rabon, Edd; Schmidt, Eric; Hamm, L. Lee

    2010-01-01

    Rhbg is a nonerythroid membrane glycoprotein belonging to the Rh antigen family. In the kidney, Rhbg is expressed at the basolateral membrane of intercalated cells of the distal nephron and is involved in NH4+ transport. We investigated the substrate specificity of Rhbg by comparing transport of NH3/NH4+ with that of methyl amine (hydrochloride) (MA/MA+), often used to replace NH3/NH4+, in oocytes expressing Rhbg. Methyl amine (HCl) in solution exists as neutral methyl amine (MA) in equilibrium with the protonated methyl ammonium (MA+). To assess transport, we used ion-selective microelectrodes and voltage-clamp experiments to measure NH3/NH4+- and MA/MA+-induced intracellular pH (pHi) changes and whole cell currents. Our data showed that in Rhbg oocytes, NH3/NH4+ caused an inward current and decrease in pHi consistent with electrogenic NH4+ transport. These changes were significantly larger than in H2O-injected oocytes. The NH3/NH4+-induced current was not inhibited in the presence of barium or in the absence of Na+. In Rhbg oocytes, MA/MA+ caused an inward current but an increase (rather than a decrease) in pHi. MA/MA+ did not cause any changes in H2O-injected oocytes. The MA/MA+-induced current and pHi increase were saturated at higher concentrations of MA/MA+. Amiloride inhibited MA/MA+-induced current and the increase in pHi in oocytes expressing Rhbg but had no effect on control oocytes. These results indicate that MA/MA+ is transported by Rhbg but differently than NH3/NH4+. The protonated MA+ is likely a direct substrate whose transport resembles that of NH4+. Transport of electroneutral MA is also enhanced by expression of Rhbg. PMID:20592240

  8. Substrate specificity of Rhbg: ammonium and methyl ammonium transport.

    PubMed

    Nakhoul, Nazih L; Abdulnour-Nakhoul, Solange M; Boulpaep, Emile L; Rabon, Edd; Schmidt, Eric; Hamm, L Lee

    2010-09-01

    Rhbg is a nonerythroid membrane glycoprotein belonging to the Rh antigen family. In the kidney, Rhbg is expressed at the basolateral membrane of intercalated cells of the distal nephron and is involved in NH4+ transport. We investigated the substrate specificity of Rhbg by comparing transport of NH3/NH4+ with that of methyl amine (hydrochloride) (MA/MA+), often used to replace NH3/NH4+, in oocytes expressing Rhbg. Methyl amine (HCl) in solution exists as neutral methyl amine (MA) in equilibrium with the protonated methyl ammonium (MA+). To assess transport, we used ion-selective microelectrodes and voltage-clamp experiments to measure NH3/NH4+- and MA/MA+-induced intracellular pH (pH(i)) changes and whole cell currents. Our data showed that in Rhbg oocytes, NH3/NH4+ caused an inward current and decrease in pH(i) consistent with electrogenic NH4+ transport. These changes were significantly larger than in H2O-injected oocytes. The NH3/NH4+-induced current was not inhibited in the presence of barium or in the absence of Na+. In Rhbg oocytes, MA/MA+ caused an inward current but an increase (rather than a decrease) in pH(i). MA/MA+ did not cause any changes in H2O-injected oocytes. The MA/MA+-induced current and pH(i) increase were saturated at higher concentrations of MA/MA+. Amiloride inhibited MA/MA+-induced current and the increase in pH(i) in oocytes expressing Rhbg but had no effect on control oocytes. These results indicate that MA/MA+ is transported by Rhbg but differently than NH3/NH4+. The protonated MA+ is likely a direct substrate whose transport resembles that of NH4+. Transport of electroneutral MA is also enhanced by expression of Rhbg.

  9. Mobile Ion Induced Slow Carrier Dynamics in Organic-Inorganic Perovskite CH₃NH₃PbBr₃.

    PubMed

    Chen, Sheng; Wen, Xiaoming; Sheng, Rui; Huang, Shujuan; Deng, Xiaofan; Green, Martin A; Ho-Baillie, Anita

    2016-03-02

    Here, we investigate photoluminescence (PL) and time-resolved photoluminescence (TRPL) in CH3NH3PbBr3 perovskite under continuous illumination, using optical and electro-optical techniques. Under continuous excitation at constant intensity, PL intensity and PL decay (carrier recombination) exhibit excitation intensity dependent reductions in the time scale of seconds to minutes. The enhanced nonradiative recombination is ascribed to light activated negative ions and their accumulation which exhibit a slow dynamics in a time scale of seconds to minutes. The observed result suggests that the organic-inorganic hybrid perovskite is a mixed electronic-ionic semiconductor. The key findings in this work suggest that ions are photoactivated or electro-activated and their accumulation at localized sites can result in a change of carrier dynamics. The findings are therefore useful for the understanding of instability of perovskite solar cells and shed light on the necessary strategies for performance improvement.

  10. Ion chemistry for the detection of isoprene and other volatile organic compounds in ambient air

    NASA Astrophysics Data System (ADS)

    Leibrock, Edeltraud; Huey, L. Gregory

    2000-06-01

    A chemical ionization mass spectrometer (CIMS) and a flowing afterglow apparatus were used to study reactions of benzene cations (C6H6+ and (C6H6)2+) with a series of volatile organic compounds (VOCs). Both cations react at the collision rate with compounds of lower ionization potential than benzene, such as isoprene (C5H8), other conjugated dienes, and aromatics. These ions are generally unreactive with substances of higher ionization potential such as alkanes, simple alcohols, simple carbonyls, etc. The results demonstrate that C6H6+ and (C6H6)2+ are excellent reagent ions for the sensitive detection of isoprene in air with a CIMS. However, 2-methyl-3-buten-2-ol (MBO) and C5H8 conjugated dienes were identified as potential interferences to this technique. This indicates that the selectivity of the CIMS isoprene measurement must be tested by intercomparison with well-established methods, e.g. gas chromatography techniques.

  11. Time-resolved studies of actin organization by multivalent ions and actin-binding proteins

    NASA Astrophysics Data System (ADS)

    Hwee Lai, Ghee; Purdy, Kirstin; Bartles, James R.; Chee Lai Wong, Gerard

    2007-03-01

    Actin is one of the principal components in the eukaryotic cytoskeleton, the architecture of which is highly regulated for a wide range of biological functions. In the presence of multivalent salts or actin-binding proteins, it is known that F-actin can organize into bundles or networks. In this work, we use time-resolved confocal microscopy to study the dynamics of actin bundle growth induced by multivalent ions and by espin, a prototypical actin binding protein that is known to induce bundles. For divalent ion induced bundles, we observe a rapid lateral saturation followed by longitudinal growth of bundles, in sharp contrast to the bundling mechanism of espin, which favors finite length bundles.

  12. Spin Frustration in an Organic Radical Ion Salt Based on a Kagome-Coupled Chain Structure.

    PubMed

    Postulka, Lars; Winter, Stephen M; Mihailov, Adam G; Mailman, Aaron; Assoud, Abdeljalil; Robertson, Craig M; Wolf, Bernd; Lang, Michael; Oakley, Richard T

    2016-08-31

    Electro-oxidation of the quinoidal bisdithiazole BT in dichloroethane in the presence of [Bu4N][GaBr4] affords the 1:1 radical ion salt [BT][GaBr4], crystals of which belong to the trigonal space group P3. The packing pattern of the radical cations provides a rare example of an organic kagome basket structure, with S = 1/2 radical ion chains located at the triangular corners of a trihexagonal lattice. Magnetic measurements over a wide temperature range from 30 mK to 300 K suggest strongly frustrated AFM interactions on the scale of J/kb ∼ 30 K, but reveal no anomalies that would be associated with magnetic order. These observations are discussed in terms of the symmetry allowed magnetic interactions within and between the frustrated layers.

  13. Organic ion imaging of biological tissue with secondary ion mass spectrometry and matrix-assisted laser desorption/ionization.

    PubMed

    Todd, P J; Schaaff, T G; Chaurand, P; Caprioli, R M

    2001-04-01

    Organic secondary ion mass spectrometry (SIMS) and matrix-assisted laser desorption/ionization (MALDI) mass spectrometry can be used to produce molecular images of samples. This is achieved through ionization from a clearly identified point on a flat sample, and performing a raster of the sample by moving the point of ionization over the sample surface. The unique analytical capabilities of mass spectrometry for mapping a variety of biological samples at the tissue level are discussed. SIMS provides information on the spatial distribution of the elements and low molecular mass compounds as well as molecular structures on these compounds, while MALDI yields spatial information about higher molecular mass compounds, including their distributions in tissues at very low levels, as well as information on the molecular structures of these compounds. Application of these methods to analytical problems requires appropriate instrumentation, sample preparation methodology, and a data presentation usually in a three-coordinate plot where x and y are physical dimensions of the sample and z is the signal amplitude. The use of imaging mass spectrometry is illustrated with several biological systems.

  14. The ground water ammonium sorption onto Croatian and Serbian clinoptilolite.

    PubMed

    Siljeg, Mario; Foglar, Lucija; Kukucka, Miroslav

    2010-06-15

    The removal of ammonium from the Valpovo region ground water (VGW) with the use of natural clinoptilolite samples from the Donje Jesenje deposit (Croatia) and the Zlatokop deposit in Vranjska Banja (Serbia) was studied. The natural Serbian (SZ) and Croatian zeolites (CZ) were transformed to the Na-form (Na-CZ and Na-SZ) in order to increase the exchange capacity of zeolite. The CZ and SZ theoretic ammonium sorption capacities were 24.24 mg NH(4)(+)/g CZ and 32.55 mg NH(4)(+)/g SZ, respectively. The application of natural and Na-form of clinoptilolite for efficient removal of ammonium ions from VGW was further investigated. For that purpose, the four "filter guard" vessels filled with zeolite samples were set in parallel in the ground water purification pilot plant. The complete ammonium removal, with the use of SZ and Na-SZ was achieved during 20 h. After having observed saturation of clinoptilolite, the samples were regenerated with the use of 2 mol/L NaCl, and reused for determination of ammonium sorption efficiency. The regenerated samples showed to be still very efficient for NH(4)(+) removal and, in addition, the SZ was shown as superior for ammonium removal in comparison to the CZ.

  15. All organic sodium-ion batteries with Na₄C₈H₂O₆.

    PubMed

    Wang, Shiwen; Wang, Lijiang; Zhu, Zhiqiang; Hu, Zhe; Zhao, Qing; Chen, Jun

    2014-06-02

    Developing organic compounds with multifunctional groups to be used as electrode materials for rechargeable sodium-ion batteries is very important. The organic tetrasodium salt of 2,5-dihydroxyterephthalic acid (Na4DHTPA; Na4C8H2O6), which was prepared through a green one-pot method, was investigated at potential windows of 1.6-2.8 V as the positive electrode or 0.1-1.8 V as the negative electrode (vs. Na(+)/Na), each delivering compatible and stable capacities of ca. 180 mAh g(-1) with excellent cycling. A combination of electrochemical, spectroscopic and computational studies revealed that reversible uptake/removal of two Na(+) ions is associated with the enolate groups at 1.6-2.8 V (Na2C8H2O6/Na4C8H2O6) and the carboxylate groups at 0.1-1.8 V (Na4C8H2O6/Na6C8H2O6). The use of Na4C8H2O6 as the initial active materials for both electrodes provided the first example of all-organic rocking-chair SIBs with an average operation voltage of 1.8 V and a practical energy density of about 65 Wh kg(-1).

  16. [Determination of organic acids in rice wine by ion-exclusion chromatography].

    PubMed

    Lin, Xiaojie; Wei, Wei; He, Zhigang; Lin, Xiaozi

    2014-03-01

    An ion-exclusion chromatographic method for the simultaneous determination of organic acids in rice wine was developed. An IC-Pak Ion Exclusion column (300 mm x 7.8 mm, 7 microm) was used at 50 degrees C. The mobile phases were H2SO4 (phase A) and acetonitrile (phase B) (98:2, v/v) at a flow rate of 0.5 mL/min. The gradient elution program was as follows: 0-40 min, 0.01 mol/L H2SO4 to 0.02 mol/L H2SO4; 40-50 min, 0.01 mol/L H2SO4. The injection volume was 10 microL. The detection wavelength was set at 210 nm. The results showed that oxalic acid, maleic acid, citric acid, tartaric acid, malic acid, ascorbic acid, succinic acid, lactic, fumaric acid, acetic acid, propionic acid, isobutyric acid and butyric acid were completely separated and determined in 30 min. The linear correlation coefficients were above 0.999 7 in the range of 0.001- 1.000 g/L. Under the optimized conditions, the recoveries of organic acids in rice wine were in the range of 93.4% - 103.8% with the relative standard deviations (RSDs, n = 5) of 0.1% - 1.5%. This method is feasible, convenient, fast, accurate and applicable for the quantitative analysis of the organic acids in rice wine.

  17. Simultaneous removal of ammonium and suspended solids in multipurpose filters.

    PubMed

    Alkas, Deniz; Baykal, Bilsen Beler; Kinaci, Cumali

    2012-06-01

    A multipurpose filter in which sand and clinoptilolite are used together as filter material is suggested for the simultaneous removal of suspended solids and ammonium in one single unit. The capacity of the clinoptilolite used was determined as 10.4 mg/g for 20 mg/l initial ammonium concentration. In addition, a packed column ion exchanger with clinoptilolite and a classical sand filter were also investigated for comparison. Ammonium and suspended solids removal rates were observed and compared for all columns. The results of the column analysis have revealed that the ammonium removal rate, which was only 20% in the sand column, was increased to 100% by replacing 50% of the sand with clinoptilolite; similarly, the suspended solids removal, which was only 17% in the clinoptilolite column, was increased to 75% by replacing 50% of the clinoptilolite with sand. As such, when ion exchange and filtration processes were carried out in a multipurpose column, high removals for both parameters could be obtained simultaneously. Multipurpose columns could be an alternative both for the upgrading of existing treatment plants or for new plants for simultaneous removal of ammonium and suspended solids, giving considerable savings in terms of land requirements.

  18. Toxicokinetics of ammonium perfluorohexanoate.

    PubMed

    Iwai, Hiroyuki

    2011-10-01

    Excretion patterns and rates of ammonium perfluorohexanoate (APFHx) after administration of a single and multiple (14 days) oral dose(s) at 50 mg/kg to male and female mice and rats were examined. The test substance was [(14)C]-labeled APFHx. After a single oral administration, total excretion was rapid, with mean recoveries of over 90% of the dose at 24 hours after administration, irrespective of gender or species. The major route of elimination was via the urine (means of percentage recovery between 73.0 and 90.2% of the dose), followed by the feces (means of percentage recovery between 7.0 and 15.5% of the dose). Elimination via expired air was negligible. For the multiple dose tests, multiple (13 daily doses) oral administration of APFHx was followed by a single oral administration of [(14)C]-APFHx. Excretion was rapid, with mean recoveries of over 90% of the administered dose (mean values >95% of the ultimately recovered material) at 24 hours after dosing, irrespective of gender or species. The major route of elimination was via the urine (means of percentage recovery between 77.8 and 83.4% of the dose), followed by the feces (means of percentage recovery between 9.6 and 12.9% of the dose).

  19. Inorganic ion composition in Tardigrada: cryptobionts contain a large fraction of unidentified organic solutes.

    PubMed

    Halberg, Kenneth Agerlin; Larsen, Kristine Wulff; Jørgensen, Aslak; Ramløv, Hans; Møbjerg, Nadja

    2013-04-01

    Many species of tardigrades are known to tolerate extreme environmental stress, yet detailed knowledge of the mechanisms underlying the remarkable adaptations of tardigrades is still lacking, as are answers to many questions regarding their basic biology. Here, we present data on the inorganic ion composition and total osmotic concentration of five different species of tardigrades (Echiniscus testudo, Milnesium tardigradum, Richtersius coronifer, Macrobiotus cf. hufelandi and Halobiotus crispae) using high-performance liquid chromatography and nanoliter osmometry. Quantification of the ionic content indicates that Na(+) and Cl(-) are the principal inorganic ions in tardigrade fluids, albeit other ions, i.e. K(+), NH4(+), Ca(2+), Mg(2+), F(-), SO4(2-) and PO4(3-) were also detected. In limno-terrestrial tardigrades, the respective ions are concentrated by a large factor compared with that of the external medium (Na(+), ×70-800; K(+), ×20-90; Ca(2+) and Mg(2+), ×30-200; F(-), ×160-1040, Cl(-), ×20-50; PO4(3-), ×700-2800; SO4(2-), ×30-150). In contrast, in the marine species H. crispae, Na(+), Cl(-) and SO4(2-) are almost in ionic equilibrium with (brackish) salt water, while K(+), Ca(2+), Mg(2+) and F(-) are only slightly concentrated (×2-10). An anion deficit of ~120 mEq l(-1) in M. tardigradum and H. crispae indicates the presence of unidentified ionic components in these species. Body fluid osmolality ranges from 361±49 mOsm kg(-1) in R. coronifer to 961±43 mOsm kg(-1) in H. crispae. Concentrations of most inorganic ions are largely identical between active and dehydrated groups of R. coronifer, suggesting that this tardigrade does not lose large quantities of inorganic ions during dehydration. The large osmotic and ionic gradients maintained by both limno-terrestrial and marine species are indicative of a powerful ion-retentive mechanism in Tardigrada. Moreover, our data indicate that cryptobiotic tardigrades contain a large fraction of unidentified

  20. Self-organized ordering of nanostructures produced by ion-beam sputtering.

    PubMed

    Castro, Mario; Cuerno, Rodolfo; Vázquez, Luis; Gago, Raúl

    2005-01-14

    We study the self-organized ordering of nanostructures produced by ion-beam sputtering of targets amorphizing under irradiation. By introducing a model akin to models of pattern formation in aeolian sand dunes, we extend consistently the current continuum theory of erosion by IBS. We obtain new nonlinear effects responsible for the in-plane ordering of the structures, whose strength correlates with the degree of ordering found in experiments. Our results highlight the importance of redeposition and surface viscous flow to this nanopattern formation process.

  1. Nitrogen removal with the anaerobic ammonium oxidation process.

    PubMed

    Hu, Ziye; Lotti, Tommaso; van Loosdrecht, Mark; Kartal, Boran

    2013-08-01

    Anaerobic ammonium-oxidizing (anammox) bacteria convert ammonium to N2 with nitrite as the terminal electron acceptor in the absence of O2. Nitritation-anammox bioreactors provide a cost-effective and environment-friendly alternative to conventional nitrification/denitrification nitrogen removal systems. Currently, this process is only applied for ammonium removal from wastewater with high ammonium load and temperature. Nevertheless, recent results obtained with laboratory-scale bioreactors suggest new possible routes of application of the Nitritation-anammox technology including (1) municipal wastewater treatment, removal of (2) methane in combination with nitrite-reducing methane-oxidizing bacteria, (3) nitrate coupled to organic acid oxidation and (4) nitrogen oxides. The current review summarizes the state-of-the-art of the application of Nitritation-anammox systems and discusses the possibilities of utilizing these recent results for wastewater treatment.

  2. A self-organized criticality model for ion temperature gradient mode driven turbulence in confined plasma

    SciTech Connect

    Isliker, H.; Pisokas, Th.; Vlahos, L.; Strintzi, D.

    2010-08-15

    A new self-organized criticality (SOC) model is introduced in the form of a cellular automaton (CA) for ion temperature gradient (ITG) mode driven turbulence in fusion plasmas. Main characteristics of the model are that it is constructed in terms of the actual physical variable, the ion temperature, and that the temporal evolution of the CA, which necessarily is in the form of rules, mimics actual physical processes as they are considered to be active in the system, i.e., a heating process and a local diffusive process that sets on if a threshold in the normalized ITG R/L{sub T} is exceeded. The model reaches the SOC state and yields ion temperature profiles of exponential shape, which exhibit very high stiffness, in that they basically are independent of the loading pattern applied. This implies that there is anomalous heat transport present in the system, despite the fact that diffusion at the local level is imposed to be of a normal kind. The distributions of the heat fluxes in the system and of the heat out-fluxes are of power-law shape. The basic properties of the model are in good qualitative agreement with experimental results.

  3. Influence of natural organic matter on the adsorption of metal ion onto clay particles

    USGS Publications Warehouse

    Schmitt, D.; Taylor, H.E.; Aiken, G.R.; Roth, D.A.; Frimmel, F.H.

    2002-01-01

    The influence of natural organic matter (NOM) on the adsorption of Al, Fe, Zn, and Pb onto clay minerals was investigated. Adsorption experiments were carried out at pH = 5 and pH = 7 in the presence and absence of NOM. In general, the presence of NOM decreased the adsorption of metal ions onto the clay particles. Al and Fe were strongly influenced by NOM, whereas Zn and Pb adsorption was only slightly altered. The interaction of the metal ions with the minerals and the influence of NOM on this interaction was investigated by coupling SdFFF with an inductively coupled plasma mass spectrometer (ICPMS) or an inductively coupled plasma atomic emission spectrometer (ICPAES). Quantitative atomization of the clay particles in the ICP was confirmed by comparing elemental content determined by direct injection of the clay into the ICPMS with values from acid digestion. Particle sizes of the clays were found to be between 0.1 and 1 μm by sedimentation field-flow fractionation (SdFFF) with UV detection. Aggregation of particles due to metal adsorption was observed using SdFFF-ICPMS measurements. This aggregation was dependent on the specific metal ion and decreased in the presence of NOM and at higher pH value.

  4. Optical metal-organic framework sensor for selective discrimination of some toxic metal ions in water.

    PubMed

    Shahat, Ahmed; Hassan, Hassan M A; Azzazy, Hassan M E

    2013-09-02

    This paper reports the development of a facile and effective approach, based on the use of Zr-based metal-organic frameworks (UiO-66) sensor with micropores geometry, shape and particle morphology for the visual detection and removal of ultra-traces of some toxic metal ions such as Bi(III), Zn(II), Pb(II), Hg(II) and Cd(II). UiO-66 was used as selective carriers for accommodating hydrophobic chromophore probes such as dithizone (DZ) without coupling agent for sensitive and selective discrimination of trace level of toxic analytes. The developed UiO-66 sensor was utilized for the detection of ultra-traces of some toxic metal ions with the naked eye. The new sensor displays high sensitivity and selectivity of a wide range of detectable metals analytes up to 10(-10) mol dm(-3) in solution, in a rapid analyte uptake response (seconds). The developed sensor is stable, cost effective, easy to prepare, and would be useful for rapid detection and removal of ultra-traces of toxic metal ions in water samples.

  5. Three-dimensional periodic supramolecular organic framework ion sponge in water and microcrystals

    NASA Astrophysics Data System (ADS)

    Tian, Jia; Zhou, Tian-You; Zhang, Shao-Chen; Aloni, Shaul; Altoe, Maria Virginia; Xie, Song-Hai; Wang, Hui; Zhang, Dan-Wei; Zhao, Xin; Liu, Yi; Li, Zhan-Ting

    2014-12-01

    Self-assembly has emerged as a powerful approach to generating complex supramolecular architectures. Despite there being many crystalline frameworks reported in the solid state, the construction of highly soluble periodic supramolecular networks in a three-dimensional space is still a challenge. Here we demonstrate that the encapsulation motif, which involves the dimerization of two aromatic units within cucurbit[8]uril, can be used to direct the co-assembly of a tetratopic molecular block and cucurbit[8]uril into a periodic three-dimensional supramolecular organic framework in water. The periodicity of the supramolecular organic framework is supported by solution-phase small-angle X-ray-scattering and diffraction experiments. Upon evaporating the solvent, the periodicity of the framework is maintained in porous microcrystals. As a supramolecular ‘ion sponge’, the framework can absorb different kinds of anionic guests, including drugs, in both water and microcrystals, and drugs absorbed in microcrystals can be released to water with selectivity.

  6. Rapid determination of drugs and semivolatile organics by direct thermal desorption ion trap mass spectrometry

    SciTech Connect

    Wise, M.B.; Ilgner, R.H.; Buchanan, M.V.; Guerin, M.R.

    1991-01-01

    Direct thermal desorption of analytes into an ion trap mass spectrometer (ITMS) is being investigated as a technique for the rapid screening of a wide variety of samples for target semivolatile organic compounds. This includes the direct detection of drugs in physiological fluids, semivolatile organic pollutants in water and waste samples, and air pollutants collected on sorbent cartridges. In order to minimize the analysis time, chromatographic separation is not performed on the sample prior to introduction into the ITMS. Instead, selective chemical ionization and tandem mass spectrometry (MS/MS) are used achieve the specificity required for the target analytes. Detection limits are typically 10--50 ppb using a 1 uL aliquot of a liquid sample without preconcentration. Sample turn-around time is 2 to 5 minutes and 3 to 5 target analytes can be quantitatively determined simultaneously. 6 figs.

  7. Ammonium and potassium removal for anaerobically digested wastewater using natural clinoptilolite followed by membrane pretreatment.

    PubMed

    Guo, Xuejun; Zeng, Le Larry; Li, Xiaomei; Park, Hung-Suck

    2008-02-28

    On the basis of the wastewater characteristic of anaerobically digested wastewater, this work studied the individual and simultaneous adsorption of ammonium and potassium ions by the natural clinoptilolite. Langmuir, Freundlich, Langmuir-Freundlich, and Toth model were employed to fit the experimental isotherm data and the fitting performances of different models were compared. Both the individual and simultaneous adsorption kinetics of ammonium and potassium were studied at various pHs and temperatures. The individual adsorption of ammonium was very fast and potassium uptake was even faster than that of ammonium. The adsorption approached equilibrium within 1h in most cases. Five models, including pseudo-first-order, pseudo-second-order, Vermeulen's model, squared driving force model and Elovich equation were used to fit the individual and simultaneous adsorption kinetics of ammonium and potassium. The validities of the fittings for the ammonium and potassium adsorption kinetics were also evaluated.

  8. A case of fatal intoxication with ammonium sulfate and a toxicological study using rabbits.

    PubMed

    Sato, A; Gonmori, K; Yoshioka, N

    1999-04-26

    Agricultural fertilizers such as ammonium sulfate are widely used in house gardens as well as in agriculture, but few case reports or toxicological studies of ingested fertilizers have been reported. This paper investigates a fatal case of ammonium sulfate poisoning and demonstrates its clinical and biochemical findings in rabbits. An 85-year-old woman was found dead lying on the ground outside her house in the middle of March, but the autopsy could not determine the cause of her death. Examination at the police laboratory of the solution in the beer can found next to her showed that it was very likely ammonium sulfate. Our measurement showed a significant increase of ammonium and sulfate ions in serum and gastric contents. The cause of her death was determined as poisoning by ammonium sulfate. The total dose of 1500 mg/kg of ammonium sulfate was administered to three rabbits, all of which showed similar symptoms such as mydriasis, irregular respiratory rhythms, local and general convulsions, until they fell into respiratory failure with cardiac arrest. EEG showed slow, suppressive waves and high-amplitude slowing wave pattern, which is generally observed clinically in hyperammonemia in man and animal. There was a remarkable increase in the concentration of ammonium ion and inorganic sulfate ion in serum, and blood gas analysis showed severe metabolic acidosis. These results, mainly findings by EEG, have shown that a rapid increase in ammonium ions in blood can cause damaging the central nervous system without microscopic change. When the cause of death can not be determined, measurement of ammonium ion, inorganic ion and electrolytes in blood as well as in stomach contents at forensic autopsy is necessary.

  9. High performance ammonium nitrate propellant

    NASA Technical Reports Server (NTRS)

    Anderson, F. A. (Inventor)

    1979-01-01

    A high performance propellant having greatly reduced hydrogen chloride emission is presented. It is comprised of: (1) a minor amount of hydrocarbon binder (10-15%), (2) at least 85% solids including ammonium nitrate as the primary oxidizer (about 40% to 70%), (3) a significant amount (5-25%) powdered metal fuel, such as aluminum, (4) a small amount (5-25%) of ammonium perchlorate as a supplementary oxidizer, and (5) optionally a small amount (0-20%) of a nitramine.

  10. A low cost, all-organic Na-ion battery based on polymeric cathode and anode.

    PubMed

    Deng, Wenwen; Liang, Xinmiao; Wu, Xianyong; Qian, Jiangfeng; Cao, Yuliang; Ai, Xinping; Feng, Jiwen; Yang, Hanxi

    2013-01-01

    Current battery systems have severe cost and resource restrictions, difficultly to meet the large scale electric storage applications. Herein, we report an all-organic Na-ion battery using p-dopable polytriphenylamine as cathode and n-type redox-active poly(anthraquinonyl sulphide) as anode, excluding the use of transition-metals as in conventional electrochemical batteries. Such a Na-ion battery can work well with a voltage output of 1.8 V and realize a considerable specific energy of 92 Wh kg(-1). Due to the structural flexibility and stability of the redox-active polymers, this battery has a superior rate capability with 60% capacity released at a very high rate of 16 C (3200 mA g(-1)) and also exhibit an excellent cycling stability with 85% capacity retention after 500 cycles at 8 C rate. Most significantly, this type of all-organic batteries could be made from renewable and earth-abundant materials, thus offering a new possibility for widespread energy storage applications.

  11. A low cost, all-organic Na-ion Battery Based on Polymeric Cathode and Anode

    PubMed Central

    Deng, Wenwen; Liang, Xinmiao; Wu, Xianyong; Qian, Jiangfeng; Cao, Yuliang; Ai, Xinping; Feng, Jiwen; Yang, Hanxi

    2013-01-01

    Current battery systems have severe cost and resource restrictions, difficultly to meet the large scale electric storage applications. Herein, we report an all-organic Na-ion battery using p-dopable polytriphenylamine as cathode and n-type redox-active poly(anthraquinonyl sulphide) as anode, excluding the use of transition-metals as in conventional electrochemical batteries. Such a Na-ion battery can work well with a voltage output of 1.8 V and realize a considerable specific energy of 92 Wh kg−1. Due to the structural flexibility and stability of the redox-active polymers, this battery has a superior rate capability with 60% capacity released at a very high rate of 16 C (3200 mA g−1) and also exhibit an excellent cycling stability with 85% capacity retention after 500 cycles at 8 C rate. Most significantly, this type of all-organic batteries could be made from renewable and earth-abundant materials, thus offering a new possibility for widespread energy storage applications. PMID:24036973

  12. Cloud water composition during HCCT-2010: Scavenging efficiencies, solute concentrations, and droplet size dependence of inorganic ions and dissolved organic carbon

    NASA Astrophysics Data System (ADS)

    van Pinxteren, D.; Fomba, K. W.; Mertes, S.; Müller, K.; Spindler, G.; Schneider, J.; Lee, T.; Collett, J.; Herrmann, H.

    2015-09-01

    Cloud water samples were taken in September/October 2010 at Mt. Schmücke in a rural, forested area in Germany during the Lagrange-type Hill Cap Cloud Thuringia 2010 (HCCT-2010) cloud experiment. Besides bulk collectors, a 3-stage and a 5-stage collector were applied and samples were analysed for inorganic ions (SO42-, NO3-, NH4+, Cl-, Na+, Mg2+, Ca2+, K+), H2O2 (aq), S(IV), and dissolved organic carbon (DOC). Campaign volume-weighted mean concentrations were 191, 142, and 39 μmol L-1 for ammonium, nitrate, and sulfate, respectively, between 4 and 27 μmol L-1 for minor ions, 5.4 μmol L-1 for H2O2 (aq), 1.9 μmol L-1 for S(IV), and 3.9 mgC L-1 for DOC. The concentrations compare well to more recent European cloud water data from similar sites. On a mass basis, organic material (as DOC · 1.8) contributed 20-40 % (event means) to total solute concentrations and was found to have non-negligible impact on cloud water acidity. Relative standard deviations of major ions were 60-66 % for solute concentrations and 52-80 % for cloud water loadings (CWLs). Contrary to some earlier suggestions, the similar variability of solute concentrations and CWLs together with the results of back trajectory analysis and principal component analysis, suggests that concentrations in incoming air masses (i.e. air mass history), rather than cloud liquid water content (LWC) was the main factor controlling bulk solute concentrations at Mt. Schmücke. Droplet effective radius was found to be a somewhat better predictor for cloud water total ionic content (TIC) than LWC, even though no single explanatory variable can fully describe TIC (or solute concentration) variations in a simple functional relation due to the complex processes involved. Bulk concentrations typically agreed within a factor of 2 with co-located measurements of residual particle concentrations sampled by a counterflow virtual impactor (CV) and analysed by an aerosol mass spectrometer (AMS), with the deviations being mainly

  13. Cloud water composition during HCCT-2010: Scavenging efficiencies, solute concentrations, and droplet size dependence of inorganic ions and dissolved organic carbon

    NASA Astrophysics Data System (ADS)

    van Pinxteren, Dominik; Wadinga Fomba, Khanneh; Mertes, Stephan; Müller, Konrad; Spindler, Gerald; Schneider, Johannes; Lee, Taehyoung; Collett, Jeffrey L.; Herrmann, Hartmut

    2016-03-01

    Cloud water samples were taken in September/October 2010 at Mt. Schmücke in a rural, forested area in Germany during the Lagrange-type Hill Cap Cloud Thuringia 2010 (HCCT-2010) cloud experiment. Besides bulk collectors, a three-stage and a five-stage collector were applied and samples were analysed for inorganic ions (SO42-,NO3-, NH4+, Cl-, Na+, Mg2+, Ca2+, K+), H2O2 (aq), S(IV), and dissolved organic carbon (DOC). Campaign volume-weighted mean concentrations were 191, 142, and 39 µmol L-1 for ammonium, nitrate, and sulfate respectively, between 4 and 27 µmol L-1 for minor ions, 5.4 µmol L-1 for H2O2 (aq), 1.9 µmol L-1 for S(IV), and 3.9 mgC L-1 for DOC. The concentrations compare well to more recent European cloud water data from similar sites. On a mass basis, organic material (as DOC × 1.8) contributed 20-40 % (event means) to total solute concentrations and was found to have non-negligible impact on cloud water acidity. Relative standard deviations of major ions were 60-66 % for solute concentrations and 52-80 % for cloud water loadings (CWLs). The similar variability of solute concentrations and CWLs together with the results of back-trajectory analysis and principal component analysis, suggests that concentrations in incoming air masses (i.e. air mass history), rather than cloud liquid water content (LWC), were the main factor controlling bulk solute concentrations for the cloud studied. Droplet effective radius was found to be a somewhat better predictor for cloud water total ionic content (TIC) than LWC, even though no single explanatory variable can fully describe TIC (or solute concentration) variations in a simple functional relation due to the complex processes involved. Bulk concentrations typically agreed within a factor of 2 with co-located measurements of residual particle concentrations sampled by a counterflow virtual impactor (CVI) and analysed by an aerosol mass spectrometer (AMS), with the deviations being mainly caused by systematic

  14. Electrochemically active, crystalline, mesoporous covalent organic frameworks on carbon nanotubes for synergistic lithium-ion battery energy storage

    NASA Astrophysics Data System (ADS)

    Xu, Fei; Jin, Shangbin; Zhong, Hui; Wu, Dingcai; Yang, Xiaoqing; Chen, Xiong; Wei, Hao; Fu, Ruowen; Jiang, Donglin

    2015-02-01

    Organic batteries free of toxic metal species could lead to a new generation of consumer energy storage devices that are safe and environmentally benign. However, the conventional organic electrodes remain problematic because of their structural instability, slow ion-diffusion dynamics, and poor electrical conductivity. Here, we report on the development of a redox-active, crystalline, mesoporous covalent organic framework (COF) on carbon nanotubes for use as electrodes; the electrode stability is enhanced by the covalent network, the ion transport is facilitated by the open meso-channels, and the electron conductivity is boosted by the carbon nanotube wires. These effects work synergistically for the storage of energy and provide lithium-ion batteries with high efficiency, robust cycle stability, and high rate capability. Our results suggest that redox-active COFs on conducting carbons could serve as a unique platform for energy storage and may facilitate the design of new organic electrodes for high-performance and environmentally benign battery devices.

  15. Effects of low-energy argon ion implantation on the dynamic organization of the actin cytoskeleton during maize pollen germination.

    PubMed

    Deng, F; Zhu, S W; Wu, L J; Cheng, B J

    2010-04-27

    The relationship between pollen germination and the dynamic organization of the actin cytoskeleton during pollen germination is a central theme in plant reproductive biology research. Maize (Zea mays) pollen grains were implanted with 30 keV argon ion (Ar(+)) beams at doses ranging from 0.78 x 10(15) to 13 x 10(15) ions/cm(2). The effects of low-energy ion implantation on pollen germination viability and the dynamic organization of the actin cytoskeleton during pollen germination were studied using confocal laser scanning microscopy. Maize pollen germination rate increased remarkably with Ar(+) dose, in the range from 3.9 x 10(15) to 6.5 x 10(15) ions/cm(2); the germination rate peaked at an Ar(+) dose of 5.2 x 10(15) ions/cm(2). When the implantation dose exceeded 7.8 x 10(15) ions/cm(2), the rate of pollen germination decreased sharply. The actin filaments assembled in pollen grains implanted with 5.2 x 10(15) ions/cm(2) Ar(+) much earlier than in controls. The actin filaments organized as longer parallel bundles and extended into the emerging pollen tube in treated pollen grains, while they formed random and loose fine bundles and were gathered at the pollen aperture in the control. The reorganization of actin cytoskeleton in the pollen implanted with 9.1 x 10(15) ions/cm(2) Ar(+) was slower than in controls. There was a positive correlation between pollen germination and the dynamic organization of the actin cytoskeleton during pollen germination. Ion implantation into pollen did not cause changes in the polarization of actin filaments and organelle dynamics in the pollen tubes. The effects of Ar(+) implantation on pollen germination could be mediated by changes in the polymerization and rearrangement of actin polymers.

  16. 21 CFR 184.1138 - Ammonium chloride.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... GRAS § 184.1138 Ammonium chloride. (a) Ammonium chloride (NH4Cl, CAS Reg. No. 12125-02-9) is produced by the reaction of sodium chloride and an ammonium salt in solution. The less soluble sodium salt... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Ammonium chloride. 184.1138 Section 184.1138...

  17. Glyoxal in aqueous ammonium sulfate solutions: products, kinetics and hydration effects.

    PubMed

    Yu, Ge; Bayer, Amanda R; Galloway, Melissa M; Korshavn, Kyle J; Fry, Charles G; Keutsch, Frank N

    2011-08-01

    Reactions and interactions between glyoxal and salts in aqueous solution were studied. Glyoxal was found to react with ammonium to form imidazole, imidazole-2-carboxaldehyde, formic acid, N-glyoxal substituted imidazole, and minor products at very low concentrations. Overall reaction orders and rates for each major product were measured. Sulfate ions have a strong and specific interaction with glyoxal in aqueous solution, which shifts the hydration equilibria of glyoxal from the unhydrated carbonyl form to the hydrated form. This ion-specific effect contributes to the observed enhancement of the effective Henry's law coefficient for glyoxal in sulfate-containing solutions. The results of UV-vis absorption and NMR spectroscopy studies of solutions of glyoxal with ammonium, methylamine, and dimethylamine salts reveal that light absorbing compounds require the formation of nitrogen containing molecules. These findings have implications on the role of glyoxal in the atmosphere, both in models of the contribution of glyoxal to form secondary organic aerosol (SOA), the role of nitrogen containing species for aerosol optical properties and in predictions of the behavior of other carbonyls or dicarbonyls in the atmosphere.

  18. Comparison of abundances, compositions and sources of elements, inorganic ions and organic compounds in atmospheric aerosols from Xi'an and New Delhi, two megacities in China and India.

    PubMed

    Li, Jianjun; Wang, Gehui; Aggarwal, Shankar G; Huang, Yao; Ren, Yanqin; Zhou, Bianhong; Singh, Khem; Gupta, Prabhat K; Cao, Junji; Zhang, Rong

    2014-04-01

    Wintertime TSP samples collected in the two megacities of Xi'an, China and New Delhi, India were analyzed for elements, inorganic ions, carbonaceous species and organic compounds to investigate the differences in chemical compositions and sources of organic aerosols. The current work is the first time comparing the composition of urban organic aerosols from China and India and discussing their sources in a single study. Our results showed that the concentrations of Ca, Fe, Ti, inorganic ions, EC, PAHs and hopanes in Xi'an are 1.3-2.9 times of those in New Delhi, which is ascribed to the higher emissions of dust and coal burning in Xi'an. In contrast, Cl(-), levoglucosan, n-alkanes, fatty alcohols, fatty acids, phthalates and bisphenol A are 0.4-3.0 times higher in New Delhi than in Xi'an, which is attributed to strong emissions from biomass burning and solid waste incineration. PAHs are carcinogenic while phthalates and bisphenol A are endocrine disrupting. Thus, the significant difference in chemical compositions of the above TSP samples may suggest that residents in Xi'an and New Delhi are exposed to environmental hazards that pose different health risks. Lower mass ratios of octadecenoic acid/octadecanoic acid (C18:1/C18:0) and benzo(a)pyrene/benzo(e)pyrene (BaP/BeP) demonstrate that aerosol particles in New Delhi are photochemically more aged. Mass closure reconstructions of the wintertime TSP indicate that crustal material is the most abundant component of ambient particles in Xi'an and New Delhi, accounting for 52% and 48% of the particle masses, respectively, followed by organic matter (24% and 23% in Xi'an and New Delhi, respectively) and secondary inorganic ions (sulfate, nitrate plus ammonium, 16% and 12% in Xi'an and New Delhi, respectively).

  19. Ammonium as a sustainable proton shuttle in bioelectrochemical systems.

    PubMed

    Cord-Ruwisch, Ralf; Law, Yingyu; Cheng, Ka Yu

    2011-10-01

    This work examines a pH control method using ammonium (NH(4)(+)) as a sustainable proton shuttle in a CEM-equipped BES. Current generation was sustained by adding NH(3) or ammonium hydroxide (NH(4)OH) to the anolyte, controlling its pH at 7. Ammonium ion migration maintained the catholyte pH at approximately 9.25. Such NH(4)(+)/NH(3) migration accounted for 90±10% of the ionic flux in the BES. Reintroducing the volatilized NH(3) from the cathode into the anolyte maintained a suitable anolyte pH for sustained microbial-driven current generation. Hence, NH(4)(+)/NH(3) acted as a proton shuttle that is not consumed in the process.

  20. 46 CFR 148.205 - Ammonium nitrate and ammonium nitrate fertilizers.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Ammonium nitrate and ammonium nitrate fertilizers. 148... Materials § 148.205 Ammonium nitrate and ammonium nitrate fertilizers. (a) This section applies to the stowage and transportation in bulk of ammonium nitrate and the following fertilizers composed of...

  1. 46 CFR 148.205 - Ammonium nitrate and ammonium nitrate fertilizers.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Ammonium nitrate and ammonium nitrate fertilizers. 148... Materials § 148.205 Ammonium nitrate and ammonium nitrate fertilizers. (a) This section applies to the stowage and transportation in bulk of ammonium nitrate and the following fertilizers composed of...

  2. 46 CFR 148.205 - Ammonium nitrate and ammonium nitrate fertilizers.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Ammonium nitrate and ammonium nitrate fertilizers. 148... Materials § 148.205 Ammonium nitrate and ammonium nitrate fertilizers. (a) This section applies to the stowage and transportation in bulk of ammonium nitrate and the following fertilizers composed of...

  3. 46 CFR 148.205 - Ammonium nitrate and ammonium nitrate fertilizers.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Ammonium nitrate and ammonium nitrate fertilizers. 148... Materials § 148.205 Ammonium nitrate and ammonium nitrate fertilizers. (a) This section applies to the stowage and transportation in bulk of ammonium nitrate and the following fertilizers composed of...

  4. Wet precipitation of major ions, polonium-210, and organic carbon in a metropolitan city, Seoul, Korea

    NASA Astrophysics Data System (ADS)

    Yan, G.; Kim, G.

    2011-12-01

    An extensive survey of chemical constituents in precipitation including dissolved organic carbon, dissolved nitrogen, major ions, trace elements, and radionuclides was conducted in a representative urban environment of Seoul over one-year period from 2009 to 2010. The sources for these chemical species were apportioned by applying principal component analysis (PCA) in association with commonly acknowledged key tracers, such as Na, K, Ca, and V. The fossil fuel combustion (especially coal) was shown to be the dominant source for most constituents being investigated, with biomass burning being recognized as another significant source. With the aid of air mass backward trajectory analyses, we concluded that the primary fraction of the chemical species in our precipitation samples originated locally in Korea, albeit the frequent long-range transport from the eastern and northeastern China might contribute substantially. Overall, our study suggests the significant role of human activities in altering the atmospheric environment of Seoul and presumably most urban areas around the world, highlighting its profound environmental implications, such as health risks posed by excessive polonium-210, enhanced rainwater acidity from organic acids, and radiative forcing by organic aerosols.

  5. Towards safer sodium-ion batteries via organic solvent/ionic liquid based hybrid electrolytes

    NASA Astrophysics Data System (ADS)

    Monti, Damien; Ponrouch, Alexandre; Palacín, M. Rosa; Johansson, Patrik

    2016-08-01

    Hybrid electrolytes aimed at application in sodium-ion batteries (SIB) consisting of an organic solvent mixture (EC:PC) and different ionic liquids (ILs); EMImTFSI, BMImTFSI, and Pyr13TFSI, and with the NaTFSI salt providing the Na+ charge carriers have here been extensively studied. The physico-chemical and electrochemical characterisation includes ionic conductivity, viscosity, density, cation coordination and solvation, various safety measures, and electrochemical stability window (ESW). Hybrid electrolytes with 10-50% of IL content were found to have ionic conductivities on par with comparable organic solvent based electrolytes, but with highly enhanced safety properties. A systematic Raman spectroscopy study of the cation coordination and solvation before and after electrolyte safety tests by ignition suggest that IL cations and TFSI remain stable when ignited while organic solvents are consumed. Finally, the solid electrolyte interphase (SEI) formed when using hybrid electrolytes has both better mechanical and electrochemical stability than the SEI derived from pure IL based electrolytes. For a half-cell with a hard carbon (HC) electrode and a hybrid electrolyte with a composition of 0.8 m NaTFSI in EC0.45:PC0.45:Pyr13TFSI0.10 encouraging results were obtained for IL based electrolytes - ca. 182 mAhg-1 at C/10 over 40 cycles.

  6. Differential mobility spectrometry with nanospray ion source as a compact detector for small organics and inorganics

    PubMed Central

    Coy, Stephen L.; Krylov, Evgeny V.; Nazarov, Erkinjon G.; Fornace, Albert J.; Kidd, Richard D.

    2013-01-01

    Electrospray ionization (ESI) is an important tool in chemical and biochemical survey and targeted analysis in many applications. For chemical detection and identification electrospray is usually used with mass spectrometry (MS). However, for screening and monitoring of chemicals of interest in light, low power field-deployable instrumentation, an alternative detection technology with chemical selectivity would be highly useful, especially since small, lightweight, chip-based gas and liquid chromatographic technologies are being developed. Our initial list of applications requiring portable instruments includes chemical surveys on Mars, medical diagnostics based on metabolites in biological samples, and water quality analysis. In this report, we evaluate ESI-Differential Mobility Spectrometry (DMS) as a compact, low-power alternative to MS detection. Use of DMS for chemically-selective detection of ESI suffers in comparison with mass spectrometry because portable MS peak capacity is greater than that of DMS by 10X or more, but the development of light, fast chip chromatography offers compensating resolution. Standalone DMS provides the chemical selectivity familiar from DMS-MS publications, and exploits the sensitivity of ion detection. We find that sub-microliter-per-minute flows and a correctly-designed interface prepare a desolvated ion stream that enables DMS to act as an effective ion filter. Results for a several small organic biomarkers and metabolites, including citric acid, azelaic acid, n-hexanoylglycine, thymidine, and caffeine, as well as compounds such as dinitrotoluene and others, have been characterized and demonstrate selective detection. Water-quality-related halogen-containing anions, fluoride through bromate, contained in liquid samples are also isolated by DMS. A reaction-chamber interface is highlighted as most practical for portable ESI-DMS instrumentation. PMID:23914140

  7. Differential mobility spectrometry with nanospray ion source as a compact detector for small organics and inorganics.

    PubMed

    Coy, Stephen L; Krylov, Evgeny V; Nazarov, Erkinjon G; Fornace, Albert J; Kidd, Richard D

    2013-09-01

    Electrospray ionization (ESI) is an important tool in chemical and biochemical survey and targeted analysis in many applications. For chemical detection and identification electrospray is usually used with mass spectrometry (MS). However, for screening and monitoring of chemicals of interest in light, low power field-deployable instrumentation, an alternative detection technology with chemical selectivity would be highly useful, especially since small, lightweight, chip-based gas and liquid chromatographic technologies are being developed. Our initial list of applications requiring portable instruments includes chemical surveys on Mars, medical diagnostics based on metabolites in biological samples, and water quality analysis. In this report, we evaluate ESI-Differential Mobility Spectrometry (DMS) as a compact, low-power alternative to MS detection. Use of DMS for chemically-selective detection of ESI suffers in comparison with mass spectrometry because portable MS peak capacity is greater than that of DMS by 10X or more, but the development of light, fast chip chromatography offers compensating resolution. Standalone DMS provides the chemical selectivity familiar from DMS-MS publications, and exploits the sensitivity of ion detection. We find that sub-microliter-per-minute flows and a correctly-designed interface prepare a desolvated ion stream that enables DMS to act as an effective ion filter. Results for a several small organic biomarkers and metabolites, including citric acid, azelaic acid, n-hexanoylglycine, thymidine, and caffeine, as well as compounds such as dinitrotoluene and others, have been characterized and demonstrate selective detection. Water-quality-related halogen-containing anions, fluoride through bromate, contained in liquid samples are also isolated by DMS. A reaction-chamber interface is highlighted as most practical for portable ESI-DMS instrumentation.

  8. Metal Ion Speciation and Dissolved Organic Matter Composition in Soil Solutions

    NASA Astrophysics Data System (ADS)

    Benedetti, M. F.; Ren, Z. L.; Bravin, M.; Tella, M.; Dai, J.

    2014-12-01

    Knowledge of the speciation of heavy metals and the role of dissolved organic matter (DOM) in soil solution is a key to understand metal mobility and ecotoxicity. In this study, soil column-Donnan membrane technique (SC-DMT) was used to measure metal speciation of Cd, Cu, Ni, Pb, and Zn in eighteen soil solutions, covering a wide range of metal sources and concentrations. DOM composition in these soil solutions was also determined. Our results show that in soil solution Pb and Cu are dominant in complex form, whereas Cd, Ni and Zn mainly exist as free ions; for the whole range of soil solutions, only 26.2% of DOM is reactive and consists mainly of fulvic acid (FA). The metal speciation measured by SC-DMT was compared to the predicted ones obtained via the NICA-Donnan model using the measured FA concentrations. The free ion concentrations predicted by speciation modelling were in good agreement with the measurements. Diffusive gradients in thin-films gels (DGT) were also performed to quantify the labile metal species in the fluxes from solid phase to solution in fourteen soils. The concentrations of metal species detected by DGT were compared with the free ion concentrations measured by DMT and the maximum concentrations calculated based on the predicted metal speciation in SC-DMT soil solutions. It is concluded that both inorganic species and a fraction of FA bound species account for the amount of labile metals measured by DGT, consistent with the dynamic features of this technique. The comparisons between measurements using analytical techniques and mechanistic model predictions provided mutual validation in their performance. Moreover, we show that to make accurate modelling of metal speciation in soil solutions, the knowledge of DOM composition is the crucial information, especially for Cu; like in previous studies the modelling of Pb speciation is not optimal and an updated of Pb generic binding parameters is required to reduce model prediction uncertainties.

  9. A maritime pine antimicrobial peptide involved in ammonium nutrition.

    PubMed

    Canales, Javier; Avila, Concepción; Cánovas, Francisco M

    2011-09-01

    A large family of small cysteine-rich antimicrobial peptides (AMPs) is involved in the innate defence of plants against pathogens. Recently, it has been shown that AMPs may also play important roles in plant growth and development. In previous work, we have identified a gene of the AMP β-barrelin family that was differentially regulated in the roots of maritime pine (Pinus pinaster Ait.) in response to changes in ammonium nutrition. Here, we present the molecular characterization of two AMP genes, PpAMP1 and PpAMP2, showing different molecular structure and physicochemical properties. PpAMP1 and PpAMP2 displayed different expression patterns in maritime pine seedlings and adult trees. Furthermore, our expression analyses indicate that PpAMP1 is the major form of AMP in the tree, and its relative abundance is regulated by ammonium availability. In contrast, PpAMP2 is expressed at much lower levels and it is not regulated by ammonium. To gain new insights into the function of PpAMP1, we over-expressed the recombinant protein in Escherichia coli and demonstrated that PpAMP1 strongly inhibited yeast growth, indicating that it exhibits antimicrobial activity. We have also found that PpAMP1 alters ammonium uptake, suggesting that it is involved in the regulation of ammonium ion flux into pine roots.

  10. Analysis of energetic materials by ion chromatography

    SciTech Connect

    Hershey, M.K.

    1985-01-01

    Ion chromatography is a rapid, sensitive, and selective method for ion analysis in a variety of matrices. Ion chromatography was used to determine levels on chloride and chlorate in potassium perchlorate. Comparisons were made with the specific ion electrons method presently being used for these analyses. Also to be discussed are ion chromatographic methods for determining ammonium in boron potassium nitrate, and chloride and ammonium in CP.

  11. A POM–organic framework anode for Li-ion battery

    DOE PAGES

    Yue, Yanfeng; Li, Yunchao; Bi, Zhonghe; ...

    2015-01-01

    Rechargeable Li-ion batteries (LIBs) are currently the dominant power source for portable electronic devices and electric vehicles, and for small-scale stationary energy storage. However, one bottleneck of the anode materials for LIBs is the poor cycling performance caused by the fact that the anodes cannot maintain their integrity over several charge–discharge cycles. In this work, we demonstrate an approach to improving the cycling performance of lithium-ion battery anodes by constructing an extended 3D network of flexible redox active polyoxometalate (POM) clusters with redox active organic linkers, herein described as POMOF. In addition, this architecture enables the accommodation of large volumemore » changes during cycling at relatively high current rates. For example, the POMOF anode exhibits a high reversible capacity of 540 mA h g–1 after 360 cycles at a current rate of 0.25C and a long cycle life at a current rate of 1.25C (>500 cycles).« less

  12. A POM–organic framework anode for Li-ion battery

    SciTech Connect

    Yue, Yanfeng; Li, Yunchao; Bi, Zhonghe; Veith, Gabriel M.; Bridges, Craig A.; Guo, Bingkun; Chen, Jihua; Mullins, David R.; Surwade, Sumedh P.; Mahurin, Shannon M.; Liu, Hongjun; Paranthaman, M. Parans; Dai, Sheng

    2015-01-01

    Rechargeable Li-ion batteries (LIBs) are currently the dominant power source for portable electronic devices and electric vehicles, and for small-scale stationary energy storage. However, one bottleneck of the anode materials for LIBs is the poor cycling performance caused by the fact that the anodes cannot maintain their integrity over several charge–discharge cycles. In this work, we demonstrate an approach to improving the cycling performance of lithium-ion battery anodes by constructing an extended 3D network of flexible redox active polyoxometalate (POM) clusters with redox active organic linkers, herein described as POMOF. In addition, this architecture enables the accommodation of large volume changes during cycling at relatively high current rates. For example, the POMOF anode exhibits a high reversible capacity of 540 mA h g–1 after 360 cycles at a current rate of 0.25C and a long cycle life at a current rate of 1.25C (>500 cycles).

  13. Permissible radionuclide loading for organic ion exchange resins from nuclear power plants

    SciTech Connect

    MacKenzie, D.R.; Lin, M.; Barletta, R.E.

    1983-10-01

    A questionnaire on the use of ion exchange resins in nuclear power plants was sent to all operating reactors in the US. Responses were received from 23 of the 48 utilities approached. Information was sought concerning the amounts of radionuclides held by the resins, and the effects of its radiation on the resins both during operation and after removal from service. Relevant information from the questionnaires is summarized and discussed. Available literature on the effects of ionizing radiation on organic ion exchange resins has been reviewed. On the basis of published data on damage to resins by radiation, the technical rationale is given to support NRC's draft branch technical position on a maximum permissible radionuclide loading. It is considered advisable to formulate the rule in terms of a delivered dose rather than a curie loading. A maximum permissible dose of 10/sup 8/ rad is chosen because, while it is large enough that a measurable amount of damage will be done to the resin, it is small enough that the damage will be negligible at a power plant or disposal site. A test procedure has been written which a generator could use to qualify a specific resin for service at a higher dose than permitted by the general rule.

  14. Evaluation of NO+ reagent ion chemistry for online measurements of atmospheric volatile organic compounds

    NASA Astrophysics Data System (ADS)

    Koss, Abigail R.; Warneke, Carsten; Yuan, Bin; Coggon, Matthew M.; Veres, Patrick R.; de Gouw, Joost A.

    2016-07-01

    NO+ chemical ionization mass spectrometry (NO+ CIMS) can achieve fast (1 Hz and faster) online measurement of trace atmospheric volatile organic compounds (VOCs) that cannot be ionized with H3O+ ions (e.g., in a PTR-MS or H3O+ CIMS instrument). Here we describe the adaptation of a high-resolution time-of-flight H3O+ CIMS instrument to use NO+ primary ion chemistry. We evaluate the NO+ technique with respect to compound specificity, sensitivity, and VOC species measured compared to H3O+. The evaluation is established by a series of experiments including laboratory investigation using a gas-chromatography (GC) interface, in situ measurement of urban air using a GC interface, and direct in situ measurement of urban air. The main findings are that (1) NO+ is useful for isomerically resolved measurements of carbonyl species; (2) NO+ can achieve sensitive detection of small (C4-C8) branched alkanes but is not unambiguous for most; and (3) compound-specific measurement of some alkanes, especially isopentane, methylpentane, and high-mass (C12-C15) n-alkanes, is possible with NO+. We also demonstrate fast in situ chemically specific measurements of C12 to C15 alkanes in ambient air.

  15. Quantitative analysis of volatile organic compounds using ion mobility spectra and cascade correlation neural networks

    NASA Technical Reports Server (NTRS)

    Harrington, Peter DEB.; Zheng, Peng

    1995-01-01

    Ion Mobility Spectrometry (IMS) is a powerful technique for trace organic analysis in the gas phase. Quantitative measurements are difficult, because IMS has a limited linear range. Factors that may affect the instrument response are pressure, temperature, and humidity. Nonlinear calibration methods, such as neural networks, may be ideally suited for IMS. Neural networks have the capability of modeling complex systems. Many neural networks suffer from long training times and overfitting. Cascade correlation neural networks train at very fast rates. They also build their own topology, that is a number of layers and number of units in each layer. By controlling the decay parameter in training neural networks, reproducible and general models may be obtained.

  16. Gold nanoparticles for the colorimetric and fluorescent detection of ions and small organic molecules

    NASA Astrophysics Data System (ADS)

    Liu, Dingbin; Wang, Zhuo; Jiang, Xingyu

    2011-04-01

    In recent years, gold nanoparticles (AuNPs) have drawn considerable research attention in the fields of catalysis, drug delivery, imaging, diagnostics, therapy and biosensors due to their unique optical and electronic properties. In this review, we summarized recent advances in the development of AuNP-based colorimetric and fluorescent assays for ions including cations (such as Hg2+, Cu2+, Pb2+, As3+, Ca2+, Al3+, etc) and anions (such as NO2-, CN-, PF6-, F-, I-, oxoanions), and small organic molecules (such as cysteine, homocysteine, trinitrotoluene, melamine and cocaine, ATP, glucose, dopamine and so forth). Many of these species adversely affect human health and the environment. Moreover, we paid particular attention to AuNP-based colorimetric and fluorescent assays in practical applications.

  17. The study and application of four kinds of organic ion-selective microsensors

    NASA Astrophysics Data System (ADS)

    Yu, Bi; Zheng, Xiao; Feng, Chu; Hong, Wen-Bing; Liu, Jun-Tao; Wang, Ru-Jiang

    1991-09-01

    Four kinds of organic ion-selective microelectrodes (two barrels, tip diameter 0.1-0.5 micron) have been developed for the measurement of acetylcholine, histamine, serotonin, and bile acid. Physiological and pathological models on the cellular or sub-cellular level have been established for the purpose of basic and clinical pharmacological research, treatment or diagnosis of certain diseases. The acetylcholine sensitive microelectrode has been applied to the study of acetylcholine activity in single erythrocytes of normal human subjects and patients suffering from manic depressive disorders. The bile acid selective microelectrode has been used for the direct measurement of intracellular bile acid activities both in colorectal cancer and colorectal mucosa in living condition.

  18. TREATMENT OF AMMONIUM NITRATE SOLUTIONS

    DOEpatents

    Boyer, T.W.; MacHutchin, J.G.; Yaffe, L.

    1958-06-10

    The treatment of waste solutions obtained in the processing of neutron- irradiated uranium containing fission products and ammonium nitrate is described. The object of this process is to provide a method whereby the ammonium nitrate is destroyed and removed from the solution so as to permit subsequent concentration of the solution.. In accordance with the process the residual nitrate solutions are treated with an excess of alkyl acid anhydride, such as acetic anhydride. Preferably, the residual nitrate solution is added to an excess of the acetic anhydride at such a rate that external heat is not required. The result of this operation is that the ammonium nitrate and acetic anhydride react to form N/sub 2/ O and acetic acid.

  19. Distinct Signaling Pathways and Transcriptome Response Signatures Differentiate Ammonium- and Nitrate-supplied Plants

    PubMed Central

    Patterson, Kurt; Cakmak, Turgay; Cooper, Andrew; Lager, Ida; Rasmusson, Allan G.; Escobar, Matthew A.

    2010-01-01

    Nitrogen is the only macronutrient that is commonly available to plants in both oxidized and reduced forms, mainly nitrate and ammonium. The physiological and molecular effects of nitrate supply have been well studied, but comparatively little is known about ammonium nutrition and its differential effects on cell function and gene expression. We have used a physiologically realistic hydroponic growth system to compare the transcriptomes and redox status of the roots of ammonium- and nitrate-supplied Arabidopsis thaliana plants. While ~60% of nitrogen-regulated genes displayed common responses to both ammonium and nitrate, significant “nitrate-specific” and “ammonium-specific” gene sets were identified. Pathways involved in cytokinin response and reductant generation/distribution were specifically altered by nitrate, while a complex biotic stress response and changes in nodulin gene expression were characteristic of ammonium-supplied plants. Nitrate supply was associated with a rapid decrease in H2O2 production, potentially due to an increased export of reductant from the mitochondrial matrix. The underlying basis of the nitrate- and ammonium-specific patterns of gene expression appears to be different signals elaborated from each nitrogen source, including alterations in extracellular pH that are associated with ammonium uptake, downstream metabolites in the ammonium assimilation pathway, and the presence or absence of the nitrate ion. PMID:20444219

  20. THE EFFECT OF ORGANIC IONS ON THE MEMBRANE POTENTIAL OF NERVES

    PubMed Central

    Wilbrandt, W.

    1937-01-01

    1. The effect of osmotic pressure on the nerve resting potential of frog sciatic nerve is in accordance with the assumption of a membrane potential; increased osmotic pressure raises, decreased osmotic pressure lowers the potential. 2. The potential of crab nerves is affected by organic and inorganic cations in the approximate series: Rb > K = diamylamine > dibutylamine > guanidine > tetraethylamine > diethylamine = dimethylamine > dipropylamine > tetramethylamine = choline = Na = Li. 3. The response of the potential to the series of dialkylamines (first decrease, then increase of response ascending in the series) is best understood by the assumption that the nerve membrane is a porous structure. 4. With respect to these salts as well as to other organic cations the dried collodion membrane as a model of a porous membrane shows a striking parallelism to the nerve membrane. 5. Both inorganic and organic anions (NO3, SCN, acetate, propionate, butyrate, lactate, pyruvate) have a definite, if slight, effect in raising the potential of crab nerves. This effect of anions indicates that the nerve membrane is not completely anion impermeable. 6. The effect of organic ions is, with certain restrictions, reversible. Its possible relation to the resting potential and to the after potentials of the electrical disturbance is discussed. 7. The response of the myelinated sciatic nerve of the frog and of the non-myelinated nerve of the spider crab show considerable agreement. There are some definite differences which are, however, not necessarily due to differences of the cell membranes involved, but may be ascribed to the difference of ionic conditions in Ringer and sea water. PMID:19873008

  1. Furfuryl-ammonium chloridozincophosphate.

    PubMed

    Kaabi, Kamel; El Glaoui, Meher; Jeanneau, Erwann; Lefebvre, Frederic; Ben Nasr, Cherif

    2010-07-31

    In the title compound, [ZnCl(HPO(4))](C(5)H(8)NO), polymeric inorganic layers constructed from ZnO(3)Cl and PO(4) tetra-hedra are linked by O atoms: O-H⋯O hydrogen bonds occur within the layers. The organic cations occupy the interlayer regions and interact with the layers by way of N-H⋯O, N-H⋯Cl, and C-H⋯Cl hydrogen bonds.

  2. Electrospray Ionization/Ion Mobility Spectrometer/Cylindrical Ion Trap Mass Spectrometer System for In-Situ Detection of Organic Compounds

    NASA Technical Reports Server (NTRS)

    Kanik, I.; Johnson, P. V.; Beegle, L. W.; Cooks, R. G.; Laughlin, B. C.; Hill, H. H.

    2003-01-01

    The potential of an Electrospray Ionization/Ion Mobility Spectrometer/Cylindrical Ion Trap Mass Spectrometer (ESI/IMS/CIT-MS) as an analytical instrument for analyzing material extracted from rock and soil samples as part of a suite of instruments on the proposed 2009 Mars Science Lander (MSL) will be demonstrated. This instrument will be able to identify volatile compounds as well as resident organic molecules on the parts-per-billion (ppb) level. Also, it will be able to obtain an inventory of chemical species on the surface of Mars which will result in a better understanding of ongoing surface chemistry. Finally, questions relevant to biological processes will be answered with the complete inventory of surface and near surface organic molecules that the ESI/IMS/CIT is capable of performing.

  3. Rapid and precise coulometric determination and separation of redox inert ions based on electrolysis for ion transfer at the aqueous|organic solution interface.

    PubMed

    Kihara, Sorin; Kasuno, Megumi

    2011-01-01

    Flow systems for precise and accurate coulometric determinations of ions that were developed on the basis of electrolytic ion transfer at the aqueous|organic solution (W|O) interface are reviewed. The electrolysis cell in the system is composed of a porous poly(tetrafluoroethylene) tube (1.0 mm inner diameter), a metal wire (0.8 mm diameter) inserted into the tube, O into which the tube is immersed, a reference electrode in O and a platinum wire counter electrode in O. The electrolysis is carried out by forcing W containing a species of interest to flow through the narrow gap between the tube and the metal wire. The coulometric determination can be performed with an efficiency of more than 99% and a precision of better than 0.2% based on the ion transfer under an optimum condition, even if the ion is redox inert such as Na(+), K(+), Mg(2+), Ca(2+), ClO(4)(-), picrate or alkylsulfonates. The system can be applied to selective electrolytic solvent extraction of ions.

  4. Simulated solvation of organic ions: protonated methylamines in water nanodroplets. Convergence toward bulk properties and the absolute proton solvation enthalpy.

    PubMed

    Houriez, Céline; Meot-Ner Mautner, Michael; Masella, Michel

    2014-06-12

    We applied an alternative, purely theoretical route to estimate thermodynamical properties of organic ions in bulk solution. The method performs a large ensemble of simulations of ions solvated in water nanodroplets of different sizes, using a polarizable molecular dynamics approach. We consider protonated ammonia and methylamines, and K(+) for comparison, solvated in droplets of 50-1000 water molecules. The parameters of the model are assigned from high level quantum computations of small clusters. All the bulk phase results extrapolated from droplet simulations match, and confirm independently, the relative and absolute experiment-based ion solvation energies. Without using experiment-based parameters or assumptions, the results confirm independently the solvation enthalpy of the proton, as -270.3 ± 1.1 kcal mol(-1). The calculated relative solvation enthalpies of these ions are constant from small water clusters, where only the ionic headgroups are solvated, up to bulk solution. This agrees with experimental thermochemistry, that the relative solvation energies of alkylammonium ions by only four H2O molecules reproduce the relative bulk solvation energies, although the small clusters lack major bulk solvation factors. The droplet results also show a slow convergence of ion solvation properties toward their bulk limit, and predict that the stepwise solvation enthalpies of ion/water droplets are very close to those of pure neutral water droplets already after 50 water molecules. Both the ionic and neutral clusters approach the bulk condensation energy very gradually up to 10,000 water molecules, consistent with the macroscopic liquid drop model for pure water droplets. Compared to standard computational methods based on infinite periodic systems, our protocol represents a new purely theoretical approach to investigate the solvation properties of ions. It is applicable to the solvation of organic ions, which are pivotal in environmental, industrial, and

  5. Elevated ammonium levels: differential acute effects on three glutamate transporter isoforms.

    PubMed

    Søgaard, Rikke; Novak, Ivana; MacAulay, Nanna

    2012-03-15

    Increased ammonium (NH(4)(+)/NH(3)) in the brain is a significant factor in the pathophysiology of hepatic encephalopathy, which involves altered glutamatergic neurotransmission. In glial cell cultures and brain slices, glutamate uptake either decreases or increases following acute ammonium exposure but the factors responsible for the opposing effects are unknown. Excitatory amino acid transporter isoforms EAAT1, EAAT2, and EAAT3 were expressed in Xenopus oocytes to study effects of ammonium exposure on their individual function. Ammonium increased EAAT1- and EAAT3-mediated [(3)H]glutamate uptake and glutamate transport currents but had no effect on EAAT2. The maximal EAAT3-mediated glutamate transport current was increased but the apparent affinities for glutamate and Na(+) were unaltered. Ammonium did not affect EAAT3-mediated transient currents, indicating that EAAT3 surface expression was not enhanced. The ammonium-induced stimulation of EAAT3 increased with increasing extracellular pH, suggesting that the gaseous form NH(3) mediates the effect. An ammonium-induced intracellular alkalinization was excluded as the cause of the enhanced EAAT3 activity because 1) ammonium acidified the oocyte cytoplasm, 2) intracellular pH buffering with MOPS did not reduce the stimulation, and 3) ammonium enhanced pH-independent cysteine transport. Our data suggest that the ammonium-elicited uptake stimulation is not caused by intracellular alkalinization or changes in the concentrations of cotransported ions but may be due to a direct effect on EAAT1/EAAT3. We predict that EAAT isoform-specific effects of ammonium combined with cell-specific differences in EAAT isoform expression may explain the conflicting reports on ammonium-induced changes in glial glutamate uptake.

  6. Application of Ion Mobility Mass Spectrometry for Identification of Gas and Particulate Phase Organic Species in the Atmosphere

    NASA Astrophysics Data System (ADS)

    Canagaratna, M. R.; Krechmer, J.; Groessl, M.; Junninen, H.; Kimmel, J.; Cubison, M.; Massoli, P.; Lin, Y. H.; Zhang, H.; Lambe, A. T.; Zhang, X.; Knochenmuss, R.; Surratt, J. D.; Jimenez, J. L.; Worsnop, D. R.

    2015-12-01

    We present recent results obtained from the application of an ion mobility time-of-flight mass spectrometer (IMS-TOF) to the detection of oxidized organic species in the atmosphere. Ion mobility mass spectrometry separates ions on the basis of their interactions with buffer gases on millisecond time scales and allows for detailed separation and identification of isomeric and isobaric molecules. Detection of highly oxidized gas phase organics is achieved by coupling the IMS-TOF to a chemical ionization scheme that utilized NO3- as the reagent ion. Oxidized gas phase molecules produced from biogenic precursors were chemically characterized with this technique during the Southern Oxidant and Aerosol Study (SOAS) field campaign as well as in laboratory experiments utilizing a potential aerosol mass (PAM) reactor. The application of IMS-TOF to aerosol phase organic species is also presented. While molecular composition of fine aerosol is often obtained by combining gas or liquid chromatography (GC or LC) with mass spectrometric detection, these techniques are limited in their ability to transfer, resolve and identify water soluble organic carbon (WSOC) species which account for a significant portion of aerosol mass. Here we demonstrate IMS as a promising alternative approach for obtaining detailed information about organic aerosol (OA) constituent species. We examine aerosol particles collected on filters during ambient and laboratory measurements. The filter extracts are subjected to electrospray ionization (ESI) before detection with the IMS-TOF. The capability of this technique to resolve WSOC species, isomers, and oligomers is highlighted.

  7. Activated boron nitride as an effective adsorbent for metal ions and organic pollutants

    PubMed Central

    Li, Jie; Xiao, Xing; Xu, Xuewen; Lin, Jing; Huang, Yang; Xue, Yanming; Jin, Peng; Zou, Jin; Tang, Chengchun

    2013-01-01

    Novel activated boron nitride (BN) as an effective adsorbent for pollutants in water and air has been reported in the present work. The activated BN was synthesized by a simple structure-directed method that enabled us to control the surface area, pore volume, crystal defects and surface groups. The obtained BN exhibits an super high surface area of 2078 m2/g, a large pore volume of 1.66 cm3/g and a special multimodal microporous/mesoporous structure located at ~ 1.3, ~ 2.7, and ~ 3.9 nm, respectively. More importantly, the novel activated BN exhibits an excellent adsorption performance for various metal ions (Cr3+, Co2+, Ni2+, Ce3+, Pb2+) and organic pollutants (tetracycline, methyl orange and congo red) in water, as well as volatile organic compounds (benzene) in air. The excellent reusability of the activated BN has also been confirmed. All the features render the activated BN a promising material suitable for environmental remediation. PMID:24220570

  8. Activated boron nitride as an effective adsorbent for metal ions and organic pollutants

    NASA Astrophysics Data System (ADS)

    Li, Jie; Xiao, Xing; Xu, Xuewen; Lin, Jing; Huang, Yang; Xue, Yanming; Jin, Peng; Zou, Jin; Tang, Chengchun

    2013-11-01

    Novel activated boron nitride (BN) as an effective adsorbent for pollutants in water and air has been reported in the present work. The activated BN was synthesized by a simple structure-directed method that enabled us to control the surface area, pore volume, crystal defects and surface groups. The obtained BN exhibits an super high surface area of 2078 m2/g, a large pore volume of 1.66 cm3/g and a special multimodal microporous/mesoporous structure located at ~ 1.3, ~ 2.7, and ~ 3.9 nm, respectively. More importantly, the novel activated BN exhibits an excellent adsorption performance for various metal ions (Cr3+, Co2+, Ni2+, Ce3+, Pb2+) and organic pollutants (tetracycline, methyl orange and congo red) in water, as well as volatile organic compounds (benzene) in air. The excellent reusability of the activated BN has also been confirmed. All the features render the activated BN a promising material suitable for environmental remediation.

  9. Three-dimensional periodic supramolecular organic framework ion sponge in water and microcrystals

    SciTech Connect

    Tian, Jia; Zhou, Tian-You; Zhang, Shao-Chen; Aloni, Shaul; Altoe, Maria Virginia; Xie, Song-Hai; Wang, Hui; Zhang, Dan-Wei; Zhao, Xin; Liu, Yi; Li, Zhan-Ting

    2014-12-02

    Self-assembly has emerged as a powerful approach to generating complex supramolecular architectures. Despite there being many crystalline frameworks reported in the solid state, the construction of highly soluble periodic supramolecular networks in a three-dimensional space is still a challenge. In this paper we demonstrate that the encapsulation motif, which involves the dimerization of two aromatic units within cucurbit[8]uril, can be used to direct the co-assembly of a tetratopic molecular block and cucurbit[8]uril into a periodic three-dimensional supramolecular organic framework in water. The periodicity of the supramolecular organic framework is supported by solution-phase small-angle X-ray-scattering and diffraction experiments. Upon evaporating the solvent, the periodicity of the framework is maintained in porous microcrystals. Lastly, as a supramolecular 'ion sponge', the framework can absorb different kinds of anionic guests, including drugs, in both water and microcrystals, and drugs absorbed in microcrystals can be released to water with selectivity.

  10. Three-dimensional periodic supramolecular organic framework ion sponge in water and microcrystals

    DOE PAGES

    Tian, Jia; Zhou, Tian-You; Zhang, Shao-Chen; ...

    2014-12-02

    Self-assembly has emerged as a powerful approach to generating complex supramolecular architectures. Despite there being many crystalline frameworks reported in the solid state, the construction of highly soluble periodic supramolecular networks in a three-dimensional space is still a challenge. In this paper we demonstrate that the encapsulation motif, which involves the dimerization of two aromatic units within cucurbit[8]uril, can be used to direct the co-assembly of a tetratopic molecular block and cucurbit[8]uril into a periodic three-dimensional supramolecular organic framework in water. The periodicity of the supramolecular organic framework is supported by solution-phase small-angle X-ray-scattering and diffraction experiments. Upon evaporating themore » solvent, the periodicity of the framework is maintained in porous microcrystals. Lastly, as a supramolecular 'ion sponge', the framework can absorb different kinds of anionic guests, including drugs, in both water and microcrystals, and drugs absorbed in microcrystals can be released to water with selectivity.« less

  11. Three-dimensional periodic supramolecular organic framework ion sponge in water and microcrystals

    PubMed Central

    Tian, Jia; Zhou, Tian-You; Zhang, Shao-Chen; Aloni, Shaul; Altoe, Maria Virginia; Xie, Song-Hai; Wang, Hui; Zhang, Dan-Wei; Zhao, Xin; Liu, Yi; Li, Zhan-Ting

    2014-01-01

    Self-assembly has emerged as a powerful approach to generating complex supramolecular architectures. Despite there being many crystalline frameworks reported in the solid state, the construction of highly soluble periodic supramolecular networks in a three-dimensional space is still a challenge. Here we demonstrate that the encapsulation motif, which involves the dimerization of two aromatic units within cucurbit[8]uril, can be used to direct the co-assembly of a tetratopic molecular block and cucurbit[8]uril into a periodic three-dimensional supramolecular organic framework in water. The periodicity of the supramolecular organic framework is supported by solution-phase small-angle X-ray-scattering and diffraction experiments. Upon evaporating the solvent, the periodicity of the framework is maintained in porous microcrystals. As a supramolecular ‘ion sponge’, the framework can absorb different kinds of anionic guests, including drugs, in both water and microcrystals, and drugs absorbed in microcrystals can be released to water with selectivity. PMID:25470406

  12. Synthesis of Nine-atom Deltahedral Zintl Ions of Germanium and their Functionalization with Organic Groups

    PubMed Central

    Gillett-Kunnath, Miriam M.; Sevov, Slavi C.

    2012-01-01

    Although the first studies of Zintl ions date between the late 1890's and early 1930's they were not structurally characterized until many years later.1,2 Their redox chemistry is even younger, just about ten years old, but despite this short history these deltahedral clusters ions E9n- (E = Si, Ge, Sn, Pb; n = 2, 3, 4) have already shown interesting and diverse reactivity and have been at the forefront of rapidly developing and exciting new chemistry.3-6 Notable milestones are the oxidative coupling of Ge94- clusters to oligomers and infinite chains,7-19 their metallation,14-16,20-25 capping by transition-metal organometallic fragments,26-34 insertion of a transition-metal atom at the center of the cluster which is sometimes combined with capping and oligomerization,35-47 addition of main-group organometallic fragments as exo-bonded substituents,48-50 and functionalization with various organic residues by reactions with organic halides and alkynes.51-58 This latter development of attaching organic fragments directly to the clusters has opened up a new field, namely organo-Zintl chemistry, that is potentially fertile for further synthetic explorations, and it is the step-by-step procedure for the synthesis of germanium-divinyl clusters described herein. The initial steps outline the synthesis of an intermetallic precursor of K4Ge9 from which the Ge94- clusters are extracted later in solution. This involves fused-silica glass blowing, arc-welding of niobium containers, and handling of highly air-sensitive materials in a glove box. The air-sensitive K4Ge9 is then dissolved in ethylenediamine in the box and then alkenylated by a reaction with Me3SiC≡CSiMe3. The reaction is followed by electrospray mass spectrometry while the resulting solution is used for obtaining single crystals containing the functionalized clusters [H2C=CH-Ge9-CH=CH2]2-. For this purpose the solution is centrifuged, filtered, and carefully layered with a toluene solution of 18-crown-6. Left

  13. Synthesis of nine-atom deltahedral Zintl ions of germanium and their functionalization with organic groups.

    PubMed

    Gillett-Kunnath, Miriam M; Sevov, Slavi C

    2012-02-11

    Although the first studies of Zintl ions date between the late 1890's and early 1930's they were not structurally characterized until many years later. Their redox chemistry is even younger, just about ten years old, but despite this short history these deltahedral clusters ions E9(n-) (E = Si, Ge, Sn, Pb; n = 2, 3, 4) have already shown interesting and diverse reactivity and have been at the forefront of rapidly developing and exciting new chemistry. Notable milestones are the oxidative coupling of Ge9(4-) clusters to oligomers and infinite chains, their metallation, capping by transition-metal organometallic fragments, insertion of a transition-metal atom at the center of the cluster which is sometimes combined with capping and oligomerization, addition of main-group organometallic fragments as exo-bonded substituents, and functionalization with various organic residues by reactions with organic halides and alkynes. This latter development of attaching organic fragments directly to the clusters has opened up a new field, namely organo-Zintl chemistry, that is potentially fertile for further synthetic explorations, and it is the step-by-step procedure for the synthesis of germanium-divinyl clusters described herein. The initial steps outline the synthesis of an intermetallic precursor of K4Ge9 from which the Ge9(4-) clusters are extracted later in solution. This involves fused-silica glass blowing, arc-welding of niobium containers, and handling of highly air-sensitive materials in a glove box. The air-sensitive K4Ge9 is then dissolved in ethylenediamine in the box and then alkenylated by a reaction with Me3SiC≡CSiMe3. The reaction is followed by electrospray mass spectrometry while the resulting solution is used for obtaining single crystals containing the functionalized clusters [H2C=CH-Ge9-CH=CH2](2-). For this purpose the solution is centrifuged, filtered, and carefully layered with a toluene solution of 18-crown-6. Left undisturbed for a few days, the so

  14. Racer (40% ammonium nonanoate) broadcast application for broadleaf weed control in spring-transplanted onions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Racer (40% ammonium nonanoate) is a newly approved herbicide for organically grown food crops. Ammonium nonanoate occurs in nature and is primarily formed from biodegradation of higher fatty acids. Field research was conducted in southeast Oklahoma (Atoka County, Lane, OK) to determine the effect ...

  15. Transformation of ammonium dicyanamide into dicyandiamide in the solid.

    PubMed

    Jürgens, Barbara; Höppe, Henning A; Irran, Elisabeth; Schnick, Wolfgang

    2002-09-23

    Ammonium dicyanamide NH(4)[N(CN)(2)] was synthesized through aqueous ion exchange. The crystal structure was investigated by single-crystal X-ray diffraction (P2(1)/c, a = 378.67(6) pm, b = 1240.9(3) pm, c = 911.84(14) pm, beta = 91.488(18) degrees, Z = 4). It derives from the CsCl structure type. Medium strong hydrogen bonds between NH(4)(+) and [N(CN)(2)](-) ions are indicative of the observed formation of dicyandiamide H(4)C(2)N(4) during heating. According to DSC and temperature-dependent X-ray powder diffractometry, this isomerization is exothermic and occurs between 102 and 106 degrees C in the solid. The reaction represents the isolobal analogue to the classical synthesis of urea by heating NH(4)OCN. While other alkali and alkaline earth dicyanamides undergo trimerization or polymerization of their anions during heating, ammonium dicyanamide thus shows a different reactivity.

  16. Lithium Ion Solvation and Diffusion in Bulk Organic Electrolytes from First-Principles and Classical Reactive Molecular Dynamics

    SciTech Connect

    Ong, Mitchell T.; Verners, Osvalds; Draeger, Erik W.; van Duin, Adri C. T.; Lordi, Vincenzo; Pask, John E.

    2014-12-19

    We report that lithium-ion battery performance is strongly influenced by the ionic conductivity of the electrolyte, which depends on the speed at which Li ions migrate across the cell and relates to their solvation structure. The choice of solvent can greatly impact both the solvation and diffusivity of Li ions. In this work, we used first-principles molecular dynamics to examine the solvation and diffusion of Li ions in the bulk organic solvents ethylene carbonate (EC), ethyl methyl carbonate (EMC), and a mixture of EC and EMC. We found that Li ions are solvated by either carbonyl or ether oxygen atoms of the solvents and sometimes by the PF $\\bar{6}$ anion. Li+ prefers a tetrahedrally coordinated first solvation shell regardless of which species are involved, with the specific preferred solvation structure dependent on the organic solvent. In addition, we calculated Li diffusion coefficients in each electrolyte, finding slightly larger diffusivities in the linear carbonate EMC compared to the cyclic carbonate EC. The magnitude of the diffusion coefficient correlates with the strength of Li+ solvation. Corresponding analysis for the PF $\\bar{6}$ anion shows greater diffusivity associated with a weakly bound, poorly defined first solvation shell. In conclusion, these results can be used to aid in the design of new electrolytes to improve Li-ion battery performance.

  17. Lithium Ion Solvation and Diffusion in Bulk Organic Electrolytes from First-Principles and Classical Reactive Molecular Dynamics

    DOE PAGES

    Ong, Mitchell T.; Verners, Osvalds; Draeger, Erik W.; ...

    2014-12-19

    We report that lithium-ion battery performance is strongly influenced by the ionic conductivity of the electrolyte, which depends on the speed at which Li ions migrate across the cell and relates to their solvation structure. The choice of solvent can greatly impact both the solvation and diffusivity of Li ions. In this work, we used first-principles molecular dynamics to examine the solvation and diffusion of Li ions in the bulk organic solvents ethylene carbonate (EC), ethyl methyl carbonate (EMC), and a mixture of EC and EMC. We found that Li ions are solvated by either carbonyl or ether oxygen atoms of the solvents and sometimes by the PF more » $$\\bar{6}$$ anion. Li+ prefers a tetrahedrally coordinated first solvation shell regardless of which species are involved, with the specific preferred solvation structure dependent on the organic solvent. In addition, we calculated Li diffusion coefficients in each electrolyte, finding slightly larger diffusivities in the linear carbonate EMC compared to the cyclic carbonate EC. The magnitude of the diffusion coefficient correlates with the strength of Li+ solvation. Corresponding analysis for the PF $$\\bar{6}$$ anion shows greater diffusivity associated with a weakly bound, poorly defined first solvation shell. In conclusion, these results can be used to aid in the design of new electrolytes to improve Li-ion battery performance.« less

  18. Electrospray/Ion Trap Mass Spectrometry for the Detection and Identification of Organisms

    SciTech Connect

    McLuckey, Scott A.; Stephenson, James L., Jr.

    1997-12-31

    Current electrospray ion trap methodology for rapid mixture analysis of proteins used for the identification of microorganisms is described. Development of ion/ion reaction techniques (e.g. reactions of multiply-charged protein cations with singly-charged anions) from both a fundamental and practical approach are presented, detailing the necessary steps and considerations involved in complex mixture analysis. Data describing the reduction of the initial charge states of electrospray ions to arbitrarily low values, the utility of ion/ion reactions for mixture separation on the millisecond time scale, and effects of excess singly-charged reactants on detection and storage efficiency are illustrated.

  19. Ion mixing, hydration, and transport in aqueous ionic systems

    SciTech Connect

    Tse, Ying-Lung Steve; Voth, Gregory A.; Witten, Thomas A.

    2015-05-14

    The enhancement effect on the ion mobility of fluoride (and that of chloride) in a polycationic system, as the chloride content increases, is shown to also exist in other more simple ionic systems with cations such as the cesium ion and an organic ammonium ion. As the chloride content increases, in addition to the finding that there is more unbound water associated with the cation, we also observe that the average lifetime of a hydrogen bond decreases. This change to the hydrogen bonds is correlated to significant changes to both the structural and dynamical properties of water. The more disordered water structure and faster water dynamics are hypothesized to be also responsible for the enhanced ion mobilities. Furthermore, when either the chloride content or hydration level is changed, the self-diffusion constant of each co-ion changes by almost the same factor, implying the existence of a single universal transport mechanism that determines ion mobilities.

  20. Optical alteration of complex organics induced by ion irradiation:. 1. Laboratory experiments suggest unusual space weathering trend

    NASA Astrophysics Data System (ADS)

    Moroz, Lyuba; Baratta, Giuseppe; Strazzulla, Giovanni; Starukhina, Larissa; Dotto, Elisabetta; Barucci, Maria Antonietta; Arnold, Gabriele; Distefano, Elisa

    2004-07-01

    Most ion irradiation experiments relevant to primitive outer Solar System objects have been performed on ice and silicate targets. Here we present the first ion irradiation experiments performed on natural complex hydrocarbons (asphaltite and kerite). These materials are very dark in the visible and have red-sloped spectra in the visible and near-infrared. They may be comparable in composition and structure to refractory organic solids on the surfaces of primitive outer Solar System objects. We irradiated the samples with 15-400 keV H +, N +, Ar ++, and He + ions and measured their reflectance spectra in the range of 0.3-2.5 μm before ion implantation and after each irradiation step. The results show that irradiation-induced carbonization gradually neutralizes the spectral slopes of these red organic solids. This implies a similar space weathering trend for the surfaces of airless bodies optically dominated by spectrally red organic components. The reduction of spectral slope was observed in all experiments. Irradiation with 30 keV protons, which transfers energy to the target mostly via electronic (inelastic) collisions, showed lower efficiency than the heavier ions. We found that spectral alteration in our experiments increased with increasing contribution of nuclear versus electronic energy loss. This implies that nuclear (elastic) energy deposition plays an important role in changing the optical properties of irradiated refractory complex hydrocarbon materials. Finally, our results indicated that temperature variations from 40 K to room temperature did not influence the spectral properties of these complex hydrocarbon solids.

  1. Benzylic Ammonium Ylide Mediated Epoxidations

    PubMed Central

    Roiser, Lukas; Robiette, Raphaël; Waser, Mario

    2016-01-01

    A high yielding synthesis of stilbene oxides using ammonium ylides has been developed. It turned out that the amine leaving group plays a crucial role as trimethylamine gives higher yields than DABCO or quinuclidine. The amine group also influences the diastereoselectivity, and detailed DFT calculations to understand the key parameters of these reactions have been carried out. PMID:27766017

  2. Salmonella enterica Strains with Reduced Susceptibility to Quarternary Ammonium Compounds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: Salmonella spp. are responsible for 76 million illnesses per year in the U.S. Quaternary ammonium compounds (QAC) are commonly used antimicrobial agents. Reduced susceptibility to these compounds by a broad spectrum of organisms is a concern. Methods: Salmonella enterica strains with r...

  3. Relations of ammonium minerals at several hydrothermal systems in the western U.S.

    NASA Astrophysics Data System (ADS)

    Krohn, M. Dennis; Kendall, Carol; Evans, John R.; Fries, Terry L.

    1993-08-01

    Ammonium bound to silicate and sulfate minerals has recently been located at several major hydrothermal systems in the western U.S. utilizing newly-discovered near-infrared spectral properties. Knowledge of the origin and mineralogic relations of ammonium minerals at known hydrothermal systems is critical for the proper interpretation of remote sensing data and for testing of possible links to mineralization. Submicroscopic analysis of ammonium minerals from two mercury- and gold-bearing hot-springs deposits at Ivanhoe, Nevada and McLaughlin, California shows that the ammonium feldspar, buddingtonite, occurs as fine-grained euhedral crystals coating larger sulfide and quartz crystals. Ammonium feldspar seems to precipitate relatively late in the crystallization sequence and shows evidence for replacement of NH 4 + by K + or other monovalent cations. Some buddingtonite is observed in close association with mercury, but not with gold. Ammonioalunite is found in a variety of isolated crystal forms at both deposits. Nitrogen isotopic values for ammonium-bearing minerals show a 14‰ range in composition, precluding assignment of a specific provenance to the nitrogen. The correlations of nitrogen isotopic values with depth and ammonium content suggest some loss of nitrogen in the oxidizing supergene environment, possibly as a metastable mineral. The high ammonium content in these hydrothermal systems, the close association to mercury, and the small crystal size of the ammonium-bearing minerals all suggest that ammonium may be transported in a late-stage vapor phase or as an organic volatile. Such a process could lead to the formation of a non-carbonaceous organic aureole above a buried geothermal source. The discovery of a 10-km outcrop of ammonium minerals confirms that significant substitution of ammonium in minerals is possible over an extensive area and that remote sensing is a feasible means to detect such aureoles.

  4. Relations of ammonium minerals at several hydrothermal systems in the western U.S.

    USGS Publications Warehouse

    Krohn, M.D.; Kendall, C.; Evans, J.R.; Fries, T.L.

    1993-01-01

    Ammonium bound to silicate and sulfate minerals has recently been located at several major hydrothermal systems in the western U.S. utilizing newly-discovered near-infrared spectral properties. Knowledge of the origin and mineralogic relations of ammonium minerals at known hydrothermal systems is critical for the proper interpretation of remote sensing data and for testing of possible links to mineralization. Submicroscopic analysis of ammonium minerals from two mercury- and gold-bearing hot-springs deposits at Ivanhoe, Nevada and McLaughlin, California shows that the ammonium feldspar, buddingtonite, occurs as fine-grained euhedral crystals coating larger sulfide and quartz crystals. Ammonium feldspar seems to precipitate relatively late in the crystallization sequence and shows evidence for replacement of NH4+ by K+ or other monovalent cations. Some buddingtonite is observed in close association with mercury, but not with gold. Ammonioalunite is found in a variety of isolated crystal forms at both deposits. Nitrogen isotopic values for ammonium-bearing minerals show a 14??? range in composition, precluding assignment of a specific provenance to the nitrogen. The correlations of nitrogen isotopic values with depth and ammonium content suggest some loss of nitrogen in the oxidizing supergene environment, possibly as a metastable mineral. The high ammonium content in these hydrothermal systems, the close association to mercury, and the small crystal size of the ammonium-bearing minerals all suggest that ammonium may be transported in a late-stage vapor phase or as an organic volatile. Such a process could lead to the formation of a non-carbonaceous organic aureole above a buried geothermal source. The discovery of a 10-km outcrop of ammonium minerals confirms that significant substitution of ammonium in minerals is possible over an extensive area and that remote sensing is a feasible means to detect such aureoles. ?? 1993.

  5. The application of ion-exchanged clay as corrosion inhibiting pigments in organic coatings

    NASA Astrophysics Data System (ADS)

    Chrisanti, Santi

    High strength aluminum alloys are used in aerospace industry and are normally coated to prevent corrosion. The corrosion protection of the coatings is mainly provided by pigmented-primer layer. Strontium chromate pigments are widely used, but they are toxic and carcinogenic. The objective of the current study is to develop and characterize the ion exchange compounds bentonite and hydrotalcite as corrosion inhibiting pigments. These compounds were synthesized with different cations and anions, and were used either alone or in mixtures as particulate additive in organic coatings. In coating applications as well as bulk solution, the inhibitor release mechanism is based on ion exchange. To evaluate corrosion inhibition, pigments extract solutions were used in potentiodynamic polarization as well as electrochemical impedance spectroscopy (EIS) experiments on bare aluminum alloy 2024-T3. Cathodic polarization showed that zinc- and cerium-containing filtrate solutions modestly inhibited cathodic current density. These solutions also decreased the extent of pitting damage formed on the surface, as compared to uninhibited 0.5 M NaCl solution. Pigments were also added as primer additives, and painted on AA2024-T3. The coated panels were then subjected to salt spray exposure testing. The possibility of sensing inhibitor exhaustion by means of X-ray diffraction interrogation of the pigment in a coating is demonstrated and discussed on cerium bentonite-pigmented coatings. Although cerium bentonite-pigmented coatings did not show behavior indicative of self-healing, the combination of bentonite and hydrotalcite that released Ce3+, Zn 2+, and PO43- showed potent scribe protection even after 3000 h exposure in salt spray. Promising self-healing was also demonstrated by pigments that consisted of decavanadate-hydrotalcite and zinc pyrovanadate, as indicated by a shiny scribed area after 1000h exposure in salt spray. When these pigments are used, blistering is minimized.

  6. From biomass to a renewable LixC6O6 organic electrode for sustainable Li-ion batteries.

    PubMed

    Chen, Haiyan; Armand, Michel; Demailly, Gilles; Dolhem, Franck; Poizot, Philippe; Tarascon, Jean-Marie

    2008-01-01

    Li-ion batteries presently operate on inorganic insertion compounds. The abundance and materials life-cycle costs of such batteries may present issues in the long term with foreseeable large-scale applications. To address the issue of sustainability of electrode materials, a radically different approach from the conventional route has been adopted to develop new organic electrode materials. The oxocarbon salt Li2C6O6 is synthesized through potentially low-cost processes free of toxic solvents and by enlisting the use of natural organic sources (CO2-harvesting entities). It contains carbonyl groups as redox centres and can electrochemically react with four Li ions per formula unit. Such battery processing comes close to both sustainable and green chemistry concepts, which are not currently present in Li-ion cell technology. The consideration of renewable resources in designing electrode materials could potentially enable the realization of green and sustainable batteries within the next decade.

  7. Induction of contact drematitis in guinea pigs by quaternary ammonium compounds: the mechanisms of antigen formation

    SciTech Connect

    Schallreuter, K.R.; Schulz, K.H.; Wood, J.M.

    1986-12-01

    Eight quaternary ammonium compounds were tested for their ability to induce contact dermatitis in guinea pigs by using a modified Freund's complete adjuvant test together with the guinea pig maximization test. Only two quaternary ammonium salts of eight tested could be designated as strong allergens. These two active substances were shown to be capable of stable association with membrane lipids in forming immunogenic complexes. This surface complexation phenomenon was confirmed by using a spin-labeled quaternary ammonium salt which competed for binding sites to the surface of epidermal cells in vivo. Electron spin resonance was used to demonstrate that stable ion-pairs are formed between binding sites and the two allergenic preservatives. Furthermore, information was obtained on the kinetics of immunogenic complex formation as well as on the position and orientation of the quaternary ammonium ion at the cell surface.

  8. Oxygen isotope analysis of fossil organic matter by secondary ion mass spectrometry

    NASA Astrophysics Data System (ADS)

    Tartèse, Romain; Chaussidon, Marc; Gurenko, Andrey; Delarue, Frédéric; Robert, François

    2016-06-01

    We have developed an analytical procedure for the measurement of oxygen isotope composition of fossil organic matter by secondary ion mass spectrometry (SIMS) at the sub-per mill level, with a spatial resolution of 20-30 μm. The oxygen isotope composition of coal and kerogen samples determined by SIMS are on average consistent with the bulk oxygen isotope compositions determined by temperature conversion elemental analysis - isotope ratio mass spectrometry (TC/EA-IRMS), but display large spreads of δ18O of ∼5-10‰, attributed to mixing of remnants of organic compounds with distinct δ18O signatures. Most of the δ18O values obtained on two kerogen residues extracted from the Eocene Clarno and Early Devonian Rhynie continental chert samples and on two immature coal samples range between ∼10‰ and ∼25‰. Based on the average δ18O values of these samples, and on the O isotope composition of water processed by plants that now constitute the Eocene Clarno kerogen, we estimated δ18Owater values ranging between around -11‰ and -1‰, which overall correspond well within the range of O isotope compositions for present-day continental waters. SIMS analyses of cyanobacteria-derived organic matter from the Silurian Zdanow chert sample yielded δ18O values in the range 12-20‰. Based on the O isotope composition measured on recent cyanobacteria from the hypersaline Lake Natron (Tanzania), and on the O isotope composition of the lake waters in which they lived, we propose that δ18O values of cyanobacteria remnants are enriched by about ∼18 ± 2‰ to 22 ± 2‰ relative to coeval waters. This relationship suggests that deep ocean waters in which the Zdanow cyanobacteria lived during Early Silurian times were characterised by δ18O values of around -5 ± 4‰. This study, establishing the feasibility of micro-analysis of Phanerozoic fossil organic matter samples by SIMS, opens the way for future investigations of kerogens preserved in Archean cherts and of the

  9. Loss of fine particle ammonium from denuded nylon filters

    NASA Astrophysics Data System (ADS)

    Yu, Xiao-Ying; Lee, Taehyoung; Ayres, Benjamin; Kreidenweis, Sonia M.; Malm, William; Collett, Jeffrey L.

    Ammonium is an important constituent of fine particulate mass in the atmosphere, but can be difficult to quantify due to possible sampling artifacts. Losses of semivolatile species such as NH 4NO 3 can be particularly problematic. In order to evaluate ammonium losses from aerosol particles collected on filters, a series of field experiments was conducted using denuded nylon and Teflon filters at Bondville, IL (February 2003), San Gorgonio, CA (April 2003 and July 2004), Grand Canyon NP, AZ (May, 2003), Brigantine, NJ (November 2003), and Great Smoky Mountains National Park (NP), TN (July-August 2004). Samples were collected over 24 h periods. Losses from denuded nylon filters ranged from 10% (monthly average) in Bondville, IL to 28% in San Gorgonio, CA in summer. Losses on individual sample days ranged from 1% to 65%. Losses tended to increase with increasing diurnal temperature and relative humidity changes and with the fraction of ambient total N(-III) (particulate NH 4++gaseous NH 3) present as gaseous NH 3. The amount of ammonium lost at most sites could be explained by the amount of NH 4NO 3 present in the sampled aerosol. Ammonium losses at Great Smoky Mountains NP, however, significantly exceeded the amount of NH 4NO 3 collected. Ammoniated organic salts are suggested as additional important contributors to observed ammonium loss at this location.

  10. Loss of Fine Particle Ammonium from Denuded Nylon Filters

    SciTech Connect

    Yu, Xiao-Ying; Lee, Taehyoung; Ayres, Benjamin; Kreidenweis, Sonia M.; Malm, William C.; Collett, Jeffrey L.

    2006-08-01

    Ammonium is an important constituent of fine particulate mass in the atmosphere, but can be difficult to quantify due to possible sampling artifacts. Losses of semivolatile species such as NH4NO3 can be particularly problematic. In order to evaluate ammonium losses from aerosol particles collected on filters, a series of field experiments was conducted using denuded nylon and Teflon filters at Bondville, Illinois (February 2003), San Gorgonio, California (April 2003 and July 2004), Grand Canyon National Park, Arizona (May, 2003), Brigantine, New Jersey (November 2003), and Great Smoky Mountains National Park (NP), Tennessee (July–August 2004). Samples were collected over 24-hr periods. Losses from denuded nylon filters ranged from 10% (monthly average) in Bondville, Illinois to 28% in San Gorgonio, California in summer. Losses on individual sample days ranged from 1% to 65%. Losses tended to increase with increasing diurnal temperature and relative humidity changes and with the fraction of ambient total N(--III) (particulate NH4+ plus gaseous NH3) present as gaseous NH3. The amount of ammonium lost at most sites could be explained by the amount of NH4NO3 present in the sampled aerosol. Ammonium losses at Great Smoky Mountains NP, however, significantly exceeded the amount of NH4NO3 collected. Ammoniated organic salts are suggested as additional important contributors to observed ammonium loss at this location.

  11. Modeling of alkyl quaternary ammonium cations intercalated into montmorillonite lattice

    SciTech Connect

    Daoudi, El Mehdi; Boughaleb, Yahia; El Gaini, Layla; Meghea, Irina; Bakasse, Mina

    2013-05-15

    Highlights: ► The modification of montmorillonites by three surfactants increases the basal spacing. ► The model proposed show a bilayer conformation for the surfactant ODTMA. ► The DODMA and TOMA surfactants adopt a paraffin type arrangement. ► Behavior of surfactants in interlayer space was confirmed by TGA and ATR analysis. - Abstract: The objective of this work was to study the conformation of the quaternary ammonium cations viz., octadecyl trimethyl ammonium (ODTMA), dioctadecyl dimethyl ammonium (DMDOA) and trioctadecyl methyl ammonium (TOMA) intercalated within montmorillonite. The modified montmorillonite was characterized by X-ray diffraction in small angle (SAXS), thermal analysis (TGA) and infrared spectroscopy of attenuated total reflection (ATR). The modification of organophilic montmorillonites by the three surfactants ODTMA, DMDOA and TOMA increases the basal spacing from their respective intercalated distances of 1.9 nm, 2.6 nm and 3.4 nm respectively. The increase in the spacing due to the basic organic modification was confirmed by the results of thermal analysis (TGA) and infrared spectroscopy (ATR), and also supported by theoretical calculations of longitudinal and transversal chain sizes of these alkyl quaternary ammonium cations.

  12. 21 CFR 582.7133 - Ammonium alginate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Ammonium alginate. 582.7133 Section 582.7133 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Ammonium alginate. (a) Product. Ammonium alginate. (b) Conditions of use. This substance is...

  13. 21 CFR 582.1141 - Ammonium phosphate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Ammonium phosphate. 582.1141 Section 582.1141 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1141 Ammonium phosphate. (a) Product. Ammonium phosphate (mono- and dibasic). (b)...

  14. 21 CFR 582.1141 - Ammonium phosphate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Ammonium phosphate. 582.1141 Section 582.1141 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1141 Ammonium phosphate. (a) Product. Ammonium phosphate (mono- and dibasic). (b)...

  15. 21 CFR 582.1141 - Ammonium phosphate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Ammonium phosphate. 582.1141 Section 582.1141 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1141 Ammonium phosphate. (a) Product. Ammonium phosphate (mono- and dibasic). (b)...

  16. 21 CFR 582.1141 - Ammonium phosphate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Ammonium phosphate. 582.1141 Section 582.1141 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1141 Ammonium phosphate. (a) Product. Ammonium phosphate (mono- and dibasic). (b)...

  17. 21 CFR 582.1141 - Ammonium phosphate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Ammonium phosphate. 582.1141 Section 582.1141 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1141 Ammonium phosphate. (a) Product. Ammonium phosphate (mono- and dibasic). (b)...

  18. 21 CFR 184.1143 - Ammonium sulfate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Ammonium sulfate. 184.1143 Section 184.1143 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Specific Substances Affirmed as GRAS § 184.1143 Ammonium sulfate. (a) Ammonium sulfate ((NH4)2SO4, CAS...

  19. 21 CFR 582.1143 - Ammonium sulfate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Ammonium sulfate. 582.1143 Section 582.1143 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1143 Ammonium sulfate. (a) Product. Ammonium sulfate. (b) Conditions of use. This...

  20. 21 CFR 582.1143 - Ammonium sulfate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Ammonium sulfate. 582.1143 Section 582.1143 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1143 Ammonium sulfate. (a) Product. Ammonium sulfate. (b) Conditions of use. This...

  1. 21 CFR 582.1143 - Ammonium sulfate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Ammonium sulfate. 582.1143 Section 582.1143 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1143 Ammonium sulfate. (a) Product. Ammonium sulfate. (b) Conditions of use. This...

  2. 21 CFR 184.1143 - Ammonium sulfate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Ammonium sulfate. 184.1143 Section 184.1143 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DIRECT... GRAS § 184.1143 Ammonium sulfate. (a) Ammonium sulfate ((NH4)2SO4, CAS Reg. No. 7783-20-2)...

  3. 21 CFR 184.1143 - Ammonium sulfate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Ammonium sulfate. 184.1143 Section 184.1143 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Specific Substances Affirmed as GRAS § 184.1143 Ammonium sulfate. (a) Ammonium sulfate ((NH4)2SO4, CAS...

  4. 21 CFR 184.1143 - Ammonium sulfate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Ammonium sulfate. 184.1143 Section 184.1143 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Specific Substances Affirmed as GRAS § 184.1143 Ammonium sulfate. (a) Ammonium sulfate ((NH4)2SO4, CAS...

  5. 21 CFR 582.1143 - Ammonium sulfate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Ammonium sulfate. 582.1143 Section 582.1143 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1143 Ammonium sulfate. (a) Product. Ammonium sulfate. (b) Conditions of use. This...

  6. 21 CFR 582.1143 - Ammonium sulfate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Ammonium sulfate. 582.1143 Section 582.1143 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1143 Ammonium sulfate. (a) Product. Ammonium sulfate. (b) Conditions of use. This...

  7. 21 CFR 184.1138 - Ammonium chloride.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    .... No. 12125-02-9) is produced by the reaction of sodium chloride and an ammonium salt in solution. The less soluble sodium salt separates out at elevated temperatures, and ammonium chloride is recovered... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Ammonium chloride. 184.1138 Section 184.1138...

  8. 21 CFR 184.1138 - Ammonium chloride.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    .... No. 12125-02-9) is produced by the reaction of sodium chloride and an ammonium salt in solution. The less soluble sodium salt separates out at elevated temperatures, and ammonium chloride is recovered... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Ammonium chloride. 184.1138 Section 184.1138...

  9. 21 CFR 184.1138 - Ammonium chloride.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    .... No. 12125-02-9) is produced by the reaction of sodium chloride and an ammonium salt in solution. The less soluble sodium salt separates out at elevated temperatures, and ammonium chloride is recovered... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ammonium chloride. 184.1138 Section 184.1138...

  10. 21 CFR 184.1138 - Ammonium chloride.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    .... No. 12125-02-9) is produced by the reaction of sodium chloride and an ammonium salt in solution. The less soluble sodium salt separates out at elevated temperatures, and ammonium chloride is recovered... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Ammonium chloride. 184.1138 Section 184.1138...

  11. 76 FR 70366 - Ammonium Nitrate Security Program

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-14

    ... SECURITY Office of the Secretary 6 CFR Part 31 RIN 1601-AA52 Ammonium Nitrate Security Program AGENCY... ``Ammonium Nitrate Security Program,'' which was published in the Federal Register on August 3, 2011. The... 62311). Under the proposed Ammonium Nitrate Security Program, the DHS will regulate the sale...

  12. 76 FR 62311 - Ammonium Nitrate Security Program

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-07

    ...; ] DEPARTMENT OF HOMELAND SECURITY Office of the Secretary 6 CFR Part 31 RIN 1601-AA52 Ammonium Nitrate Security...), entitled ``Ammonium Nitrate Security Program,'' which was published in the Federal Register on August 3... of ammonium nitrate pursuant to section 563 of the Fiscal Year 2008 Department of Homeland...

  13. 76 FR 11273 - Ammonium Nitrate From Russia

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-01

    ... COMMISSION Ammonium Nitrate From Russia AGENCY: United States International Trade Commission. ACTION: Institution of a five-year review concerning the suspended investigation on ammonium nitrate from Russia... investigation on ammonium nitrate from Russia would be likely to lead to continuation or recurrence of...

  14. 76 FR 47238 - Ammonium Nitrate From Russia

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-04

    ... COMMISSION Ammonium Nitrate From Russia Determination On the basis of the record \\1\\ developed in the subject... order on ammonium nitrate from Russia would be likely to lead to continuation or recurrence of material... Commission are contained in USITC Publication 4249 (August 2011), entitled Ammonium Nitrate from...

  15. 21 CFR 556.375 - Maduramicin ammonium.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... residues of maduramicin ammonium in chickens as follows: (a) A tolerance for maduramicin ammonium (marker residue) in chickens is 0.38 parts per million in fat (target tissue). A tolerance refers to the... animals. (b) The safe concentrations for total maduramicin ammonium residues in uncooked edible...

  16. Removal of mercury (II), elemental mercury and arsenic from simulated flue gas by ammonium sulphide.

    PubMed

    Ning, Ping; Guo, Xiaolong; Wang, Xueqian; Wang, Ping; Ma, Yixing; Lan, Yi

    2015-01-01

    A tubular resistance furnace was used as a reactor to simulate mercury and arsenic in smelter flue gases by heating mercury and arsenic compounds. The flue gas containing Hg(2+), Hg(0) and As was treated with ammonium sulphide. The experiment was conducted to investigate the effects of varying the concentration of ammonium sulphide, the pH value of ammonium sulphide, the temperature of ammonium sulphide, the presence of SO2 and the presence of sulphite ion on removal efficiency. The prepared adsorption products were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and scanning electron microscopy. The results showed that the optimal concentration of ammonium sulphide was 0.8 mol/L. The optimal pH value of ammonium sulphide was 10, and the optimal temperature of ammonium sulphide was 20°C.Under the optimum conditions, the removal efficiency of Hg(2+), Hg(0) and As could reach 99%, 88.8%, 98%, respectively. In addition, SO2 and sulphite ion could reduce the removal efficiency of mercury and arsenic from simulated flue gas.

  17. Molecular Characterization and Reactivity of Dissolved Organic Matter by High Resolution Nanospray Ionization Fourier Transform-Ion Cyclotron Resonance Mass Spectrometry (FTICR-MS)

    NASA Astrophysics Data System (ADS)

    Sleighter, R. L.; Hatcher, S. A.; Hatcher, P. G.

    2006-12-01

    The ultrahigh resolving power of FTICR-MS allows for the intense characterization of dissolved organic matter (DOM). DOM is the largest reactive component of the global carbon cycle, and an improved understanding of its composition is necessary to determine the transport and eventual fate of pollutants. The seasonal and spatial variations in DOM composition are investigated by taking surface water samples from five different sampling sites, four times a year. Water sampling begins at the Dismal Swamp in North Carolina, continues north up the Elizabeth River to the Chesapeake Bay, and concludes approximately ten miles off the coast in the Atlantic Ocean. DOM was extracted from the water samples using C18 extraction disks and were prepared in 50:50 methanol:water. Ammonium hydroxide was added prior to nanospray in order to solubilize the DOM as well as to increase the ionization efficiency. The samples were continuously infused into the Apollo II ion source with an Advion TriVersa NanoMate system of a Bruker 12 Tesla Apex QE FTICR-MS with resolving powers exceeding 400,000. All samples were analyzed in negative ion mode and were externally and internally calibrated prior to data analysis. Our DOM mass spectra consist of a multitude of peaks spanning the range of 200-850 m/z. Complexity is apparent from the detection of up to 20 peaks per nominal mass at nearly every mass throughout that range. A molecular formula calculator generated molecular formula matches from which van Krevelen plots were constructed for characterization purposes. A wide range of molecules were observed each containing oxygen, sulfur and nitrogen functional groups. We utilize the van Krevelen diagram to assist in clustering the molecules according to their functional group compositions. To test the hypothesis that formation of adducts to DOM serve to protect peptides from bacterial degradation, microcosm experiments were performed with a small isotopically enriched peptide, GGGR. This peptide

  18. A volatile organic analyzer for Space Station: Description and evaluation of a gas chromatography/ ion mobility

    NASA Technical Reports Server (NTRS)

    Limero, Thomas F.; James, John T.

    1994-01-01

    A Volatile Organic Analyzer (VOA) is being developed as an essential component of the Space Station's Environmental Health System (EHS) air quality monitoring strategy to provide warning to the crew and ground personnel if volatile organic compounds exceed established exposure limits. The short duration of most Shuttle flights and the relative simplicity of the contaminant removal mechanism have lessened the concern about crew exposure to air contaminants on the Shuttle. However, the longer missions associated with the Space Station, the complex air revitalization system and the proposed number of experiments have led to a desire for real-time monitoring of the contaminants in the Space Station atmosphere. Achieving the performance requirements established for the VOA within the Space Station resource (e.g., power, weight) allocations led to a novel approach that joined a gas chromatograph (GC) to an ion mobility spectrometer (IMS). The authors of this paper will discuss the rational for selecting the GC/IMS technology as opposed to the more established gas chromatography/mass spectrometry (GC/MS) for the foundation of the VOA. The data presented from preliminary evaluations will demonstrate the versatile capability of the GC/IMS to analyze the major contaminants expected in the Space Station atmosphere. The favorable GC/IMS characteristics illustrated in this paper included excellent sensitivity, dual-mode operation for selective detection, and mobility drift times to distinguish co-eluting GC peaks. Preliminary studies have shown that the GC/IMS technology can meet surpass the performance requirements of the Space Station VOA.

  19. Assessment of the potential for ammonium nitrate formation and reaction in Tank 241-SY-101

    SciTech Connect

    Pederson, L.R.; Bryan, S.A.

    1994-08-01

    Two principal scenarios by which ammonium nitrate may be formed were considered: (a) precipitation of ammonium nitrate in the waste, and (b) ammonium nitrate formation via the gas phase reaction of ammonia and nitrogen dioxide. The first of these can be dismissed because ammonium ions, which are necessary for ammonium nitrate precipitation, can exist only in negligibly small concentrations in strongly alkaline solutions. Gas phase reactions between ammonia, nitrogen dioxide, and water vapor in the gas phase represent the most likely means by which ammonium nitrate aerosols could be formed in Tank 241-SY-101. Predicted ammonium nitrate formation rates are largely controlled by the concentration of nitrogen dioxide. This gas has not been detected among those gases vented from the wastes using Fourier Transform Infrared Spectrometry (FTIR) or mass spectrometry. While detection limits for nitrogen dioxide have not been established experimentally, the maximum concentration of nitrogen dioxide in the gas phase in Tank 241-SY-101 was estimated at 0.1 ppm based on calculations using the HITRAN data base and on FTIR spectra of gases vented from the wastes. At 50 C and with 100 ppm ammonia also present, less than one gram of ammonium nitrate per year is estimated to be formed in the tank. To date, ammonium nitrate has not been detected on HEPA filters in the ventilation system, so any quantity that has been formed in the tank must be quite small, in good agreement with rate calculations. The potential for runaway exothermic reactions involving ammonium nitrate in Tank 241-SY-101 is minimal. Dilution by non-reacting waste components, particularly water, would prevent hazardous exothermic reactions from occurring within the waste slurry, even if ammonium nitrate were present. 41 refs.

  20. Reassimilation of ammonium in Lotus japonicus.

    PubMed

    Betti, Marco; García-Calderón, Margarita; Pérez-Delgado, Carmen M; Credali, Alfredo; Pal'ove-Balang, Peter; Estivill, Guillermo; Repčák, Miroslav; Vega, José M; Galván, Francisco; Márquez, Antonio J

    2014-10-01

    This review summarizes the most recent results obtained in the analysis of two important metabolic pathways involved in the release of internal sources of ammonium in the model legume Lotus japonicus: photorespiratory metabolism and asparagine breakdown mediated by aparaginase (NSE). The use of photorespiratory mutants deficient in plastidic glutamine synthetase (GS2) enabled us to investigate the transcriptomics and metabolomic changes associated with photorespiratory ammonium accumulation in this plant. The results obtained indicate the existence of a coordinate regulation of genes involved in photorespiratory metabolism. Other types of evidence illustrate the multiple interconnections existing among the photorespiratory pathway and other processes such as intermediate metabolism, nodule function, and secondary metabolism in this plant, all of which are substantially affected in GS2-deficient mutants because of the impairment of the photorespiratory cycle. Finally, the importance of asparagine metabolism in L. japonicus is highlighted because of the fact that asparagine constitutes the vast majority of the reduced nitrogen translocated between different organs of this plant. The different types of NSE enzymes and genes which are present in L. japonicus are described. There is a particular focus on the most abundant K(+)-dependent LjNSE1 isoform and how TILLING mutants were used to demonstrate by reverse genetics the importance of this particular isoform in plant growth and seed production.

  1. [Simultaneous determination of 16 organic acids in feed additives by on-line enrichment and ion chromatography-mass spectrometry].

    PubMed

    Xiong, Zhiyu; Dong, Ying; Zhou, Hongbin; Yu, Yang; Li, Jing; Sun, Li

    2014-02-01

    A novel analytical method for simultaneous determination of sixteen organic acids by on-line enrichment and ion chromatography-mass spectrometry (IC-MS) was developed. Online enrichment and separation of the organic acids were performed by ion chromatography on a homemade enrichment column and a homemade separation column. The qualitative and quantitative analyses of the organic acids were performed by mass spectrometry in selected ion monitoring (SIM) mode on the basis of atmospheric pressure chemical ionization (APCI) source in negative mode. The sample of 200 microL was injected for the analysis, and the on-line enrichment time was 3 min. The sodium hydroxide solution was used as a gradient elution system. The two columns made it possible to have a low limit of detection due to the good enrichment and separation capability. The sixteen organic acids were separated completely within 30 min. All curves showed good linearity within the test concentration ranges. The limits of detection (LODs) were between 0.01 and 0.22 mg/L, and the average recoveries were between 70.6% and 110.8%. The relative standard deviations (RSDs) were less than 6.3%. The results indicate that this method is simple, rapid, sensitive and accurate for the determination of the organic acids in feed additives.

  2. The toxicity of the quaternary ammonium compound benzalkonium chloride alone and in mixtures with other anionic compounds to bacteria in test systems with Vibrio fischeri and Pseudomonas putida.

    PubMed

    Sütterlin, H; Alexy, R; Kümmerer, K

    2008-10-01

    Mixtures of chemicals are present in the aquatic environment but standard testing methods assess only single compounds. One aspect of this question is the importance of the formation of ionic pairs, for example from quaternary ammonium compounds with organic anions, and the significance of the ionic pairs for bacterial toxicity in the aquatic environment. The aim of the present study was to investigate the toxicity of the cationic quaternary ammonium compound benzalkonium chloride (BAC) against aquatic bacteria in the presence of substances commonly found in wastewater, such as the anionic surfactant linear alkylbenzene sulfonate (LAS), naphthalene sulfonic acid (NSA), sodium dodecylsulfonate (SDS), and benzene sulfonic acid (BSA). The growth inhibition test with Pseudomonas putida and the Vibrio fischeri luminescent inhibition test were used to determine the toxicity of single compounds and compound mixtures. The results found in this study indicate that ion pair formation is of minor significance under the test conditions applied here.

  3. Systematic studies on reactive ion etch-induced deformations of organic underlayers

    NASA Astrophysics Data System (ADS)

    Glodde, Martin; Engelmann, Sebastian; Guillorn, Michael; Kanakasabapathy, Sivananda; Mclellan, Erin; Koay, Chiew-Seng; Yin, Yunpeng; Sankarapandian, Muthumanickam; Arnold, John C.; Petrillo, Karen; Brink, Markus; Miyazoe, Hiroyuki; de Silva, E. Anuja; Yusuff, Hakeem; Yoon, Kwang-sub; Wei, Yayi; Wu, Chung-hsi J.; Varanasi, P. Rao

    2011-04-01

    Underlayers (UL), such as organic planarizing layers (OPLs) or spin-on carbon (SOC) layers, play a very important role in various integration schemes of chip manufacturing. One function of OPLs is to fill in pre-existing patterns on the substrate, such as previously patterned vias, to enable lithographic patterning of the next level. More importantly, OPL resistance to reactive ion etch (RIE) processes used to etch silicon-containing materials is essential for the successful pattern transfer from the resist into the substrate. Typically, the pattern is first transferred into the OPL through a two-step RIE sequence, followed by the transfer into the substrate by a fluorine-containing RIE step that leaves the OPL pattern mainly intact. However, when the line/space patterns are scaled down to line widths below 35 nm, it was found that this last RIE step induces severe pattern deformation ("wiggling") of the OPL material, which ultimately prevents the successful pattern transfer into the substrate. In this work, we developed an efficient process to evaluate OPL materials with respect to their pattern transfer performance. This allowed us to systematically study material, substrate and etch process parameters and draw conclusions about how changes in these parameters may improve the overall pattern transfer margin.

  4. Inelastic scattering of electron and light ion beams in organic polymers

    SciTech Connect

    Vera, Pablo de; Abril, Isabel; Garcia-Molina, Rafael

    2011-05-01

    We have calculated the inelastic mean free path, stopping power, and energy-loss straggling of swift electron, proton, and {alpha}-particle beams in a broad incident energy range in four organic polymers: poly(methyl methacrylate) (PMMA), Kapton, polyacetylene (PA), and poly(2-vinylpyridine) (P2VP). These calculations have been done through a suitable description of their optical properties and its extension into the whole momentum and energy transfer excitation spectrum. For electrons, we take into account the exchange effect between the projectile and the target electrons, while the charge-state fractions have been considered for ions. Our results are compared with other models and with the available experimental data. An excellent agreement with experimental data is obtained in the case of proton and {alpha}-particle beams in Kapton and a reasonably good agreement has been achieved for electron beams in PMMA, Kapton, and PA. We have parameterized by means of simple analytical expressions our results for electron beams interacting with these four polymers, which can be easily implemented in Monte Carlo calculations.

  5. Dynamics of Protonated Peptide Ion Collisions with Organic Surfaces: Consonance of Simulation and Experiment

    SciTech Connect

    Pratihar, Subha; Barnes, George L.; Laskin, Julia; Hase, William L.

    2016-08-18

    In this Perspective mass spectrometry experiments and chemical dynamics simulations are described which have explored the atomistic dynamics of protonated peptide ions, peptide-H+, colliding with organic surfaces. These studies have investigated surface-induced dissociation (SID) for which peptide-H+ fragments upon collision with the surface, peptide-H+ physisorption on the surface, soft landing (SL), and peptide-H+ reaction with the surface, reactive landing (RL). The simulations include QM+MM and QM/MM direct dynamics. For collisions with self-assembled monolayer (SAM) surfaces there is quite good agreement between experiment and simulation in the efficiency of energy transfer to the peptide-H+ ion’s internal degrees of freedom. Both the experiments and simulations show two mechanisms for peptide-H+ fragmentation, i.e. shattering and statistical, RRKM dynamics. Mechanisms for SL are probed in simulations of collisions of protonated dialanine with a perfluorinated SAM surface. RL has been studied experimentally for a number of peptide-H+ + surface systems, and qualitative agreement between simulation and experiment is found for two similar systems.

  6. A flowing atmospheric pressure afterglow as an ion source coupled to a differential mobility analyzer for volatile organic compound detection.

    PubMed

    Bouza, Marcos; Orejas, Jaime; López-Vidal, Silvia; Pisonero, Jorge; Bordel, Nerea; Pereiro, Rosario; Sanz-Medel, Alfredo

    2016-05-23

    Atmospheric pressure glow discharges have been widely used in the last decade as ion sources in ambient mass spectrometry analyses. Here, an in-house flowing atmospheric pressure afterglow (FAPA) has been developed as an alternative ion source for differential mobility analysis (DMA). The discharge source parameters (inter-electrode distance, current and helium flow rate) determining the atmospheric plasma characteristics have been optimized in terms of DMA spectral simplicity with the highest achievable sensitivity while keeping an adequate plasma stability and so the FAPA working conditions finally selected were: 35 mA, 1 L min(-1) of He and an inter-electrode distance of 8 mm. Room temperature in the DMA proved to be adequate for the coupling and chemical analysis with the FAPA source. Positive and negative ions for different volatile organic compounds were tested and analysed by FAPA-DMA using a Faraday cup as a detector and proper operation in both modes was possible (without changes in FAPA operational parameters). The FAPA ionization source showed simpler ion mobility spectra with narrower peaks and a better, or similar, sensitivity than conventional UV-photoionization for DMA analysis in positive mode. Particularly, the negative mode proved to be a promising field of further research for the FAPA ion source coupled to ion mobility, clearly competitive with other more conventional plasmas such as corona discharge.

  7. Effect of ten quaternary ammonium cations on tetrachloromethane sorption to clay from water

    USGS Publications Warehouse

    Smith, J.A.

    1990-01-01

    The mineral surface of Wyoming bentonite (clay) was modified by replacing inorganic ions by each of 10 quaternary ammonium compounds, and tetrachloromethane sorption to the modified sorbents from water was studied. Tetrachloromethane sorption from solution to clay modified with tetramethyl-, tetraethyl-, benzyltrimethyl-, or benzyltriethylammonium cations generally is characterized by relatively high solute uptake, isotherm nonlinearity, and competitive sorption (with trichloroethene as the competing sorbate). For these sorbents, the ethyl functional groups yield reduced sorptive capacity relative to methyl groups, whereas the benzyl group appears to have a similar effect on sorbent capacity as the methyl group. Sorption of tetrachloromethane to clay modified with dodecyldimethyl(2-phenoxyethyl)-, dodecyltrimethyl-, tetradecyltrimethyl-, hexadecyltrimethyl-, or benzyldimethylhexadecylammonium bromide is characterized by relatively low solute uptake, isotherm linearity, and noncompetitive sorption. For these sorbents, an increase in the size of the nonpolar functional group(s) causes an increase in the organic carbon normalized sorption coefficient (Koc). No measurable uptake of tetrachloromethane sorption by the unmodified clay or clay modified by ammonium bromide was observed. ?? 1990 American Chemical Society.

  8. RAPID COMMUNICATION: Self-quenching of excited europium ions in Eu(DBM)3bath-based organic electroluminescent devices

    NASA Astrophysics Data System (ADS)

    Liang, C. J.; Wong, T. C.; Hung, L. S.; Lee, S. T.; Hong, Z. R.; Li, W. L.

    2001-06-01

    Luminance-current characteristics of organic electroluminescent devices based on the europium complex of europium(dibenzoylmethanato)3 (bathophenanthroline) (Eu(DBM)3bath) have been investigated. Transient measurements were carried out to study the decay process of excited Eu3+ ions. A comparison of experimental data and theoretical calculation shows that biexcitonic quenching among the excited Eu3+ ions is an important channel in their decay process, and this quenching process is a primary cause for our observation of a rapid decrease in quantum efficiency with increasing current density. Extending the recombination zone is found to be beneficial to reducing this defective effect. The mechanism of the quenching process is also discussed.

  9. A Volatile Organic Analyzer for Space Station - Description and evaluation of a gas chromatography/ion mobility spectrometer

    NASA Technical Reports Server (NTRS)

    Limero, Thomas; Brokenshire, John; Cumming, Colin; Overton, ED; Carney, Ken; Cross, Jay; Eiceman, Gary; James, John

    1992-01-01

    An on-board Volatile Organic Analyzer (VOA), an essential component of the Environmental Health System (EHS) air-quality monitoring strategy, is described. The strategy is aimed at warning the crew and ground personnel if volatile compounds exceed safe exposure limits. The VOA uses a combination of gas chromatography (GC) and ion-mobility spectrometry (IMS) for environmental monitoring and analysis. It is concluded that the VOA dual-mode detection capability and the ion mobilities in the drift region are unique features that can assist in the resolution of coeluting GC peaks. The VOA is capable of accurately identifying and quantifying target compounds in a complex mixture.

  10. Theory of ion transport with fast acid-base equilibrations in bioelectrochemical systems.

    PubMed

    Dykstra, J E; Biesheuvel, P M; Bruning, H; Ter Heijne, A

    2014-07-01

    Bioelectrochemical systems recover valuable components and energy in the form of hydrogen or electricity from aqueous organic streams. We derive a one-dimensional steady-state model for ion transport in a bioelectrochemical system, with the ions subject to diffusional and electrical forces. Since most of the ionic species can undergo acid-base reactions, ion transport is combined in our model with infinitely fast ion acid-base equilibrations. The model describes the current-induced ammonia evaporation and recovery at the cathode side of a bioelectrochemical system that runs on an organic stream containing ammonium ions. We identify that the rate of ammonia evaporation depends not only on the current but also on the flow rate of gas in the cathode chamber, the diffusion of ammonia from the cathode back into the anode chamber, through the ion exchange membrane placed in between, and the membrane charge density.

  11. Theory of ion transport with fast acid-base equilibrations in bioelectrochemical systems

    NASA Astrophysics Data System (ADS)

    Dykstra, J. E.; Biesheuvel, P. M.; Bruning, H.; Ter Heijne, A.

    2014-07-01

    Bioelectrochemical systems recover valuable components and energy in the form of hydrogen or electricity from aqueous organic streams. We derive a one-dimensional steady-state model for ion transport in a bioelectrochemical system, with the ions subject to diffusional and electrical forces. Since most of the ionic species can undergo acid-base reactions, ion transport is combined in our model with infinitely fast ion acid-base equilibrations. The model describes the current-induced ammonia evaporation and recovery at the cathode side of a bioelectrochemical system that runs on an organic stream containing ammonium ions. We identify that the rate of ammonia evaporation depends not only on the current but also on the flow rate of gas in the cathode chamber, the diffusion of ammonia from the cathode back into the anode chamber, through the ion exchange membrane placed in between, and the membrane charge density.

  12. Organic solvent and temperature-enhanced ion chromatography-high resolution mass spectrometry for the determination of low molecular weight organic and inorganic anions.

    PubMed

    Gilchrist, Elizabeth S; Nesterenko, Pavel N; Smith, Norman W; Barron, Leon P

    2015-03-20

    There has recently been increased interest in coupling ion chromatography (IC) to high resolution mass spectrometry (HRMS) to enable highly sensitive and selective analysis. Herein, the first comprehensive study focusing on the direct coupling of suppressed IC to HRMS without the need for post-suppressor organic solvent modification is presented. Chromatographic selectivity and added HRMS sensitivity offered by organic solvent-modified IC eluents on a modern hyper-crosslinked polymeric anion-exchange resin (IonPac AS18) are shown using isocratic eluents containing 5-50 mM hydroxide with 0-80% methanol or acetonitrile for a range of low molecular weight anions (<165 Da). Comprehensive experiments on IC thermodynamics over a temperature range between 20-45 °C with the eluent containing up to 60% of acetonitrile or methanol revealed markedly different retention behaviour and selectivity for the selected analytes on the same polymer based ion-exchange resin. Optimised sensitivity with HRMS was achieved with as low as 30-40% organic eluent content. Analytical performance characteristics are presented and compared with other IC-MS based works. This study also presents the first application of IC-HRMS to forensic detection of trace low-order anionic explosive residues in latent human fingermarks.

  13. Electrochemically active, crystalline, mesoporous covalent organic frameworks on carbon nanotubes for synergistic lithium-ion battery energy storage

    PubMed Central

    Xu, Fei; Jin, Shangbin; Zhong, Hui; Wu, Dingcai; Yang, Xiaoqing; Chen, Xiong; Wei, Hao; Fu, Ruowen; Jiang, Donglin

    2015-01-01

    Organic batteries free of toxic metal species could lead to a new generation of consumer energy storage devices that are safe and environmentally benign. However, the conventional organic electrodes remain problematic because of their structural instability, slow ion-diffusion dynamics, and poor electrical conductivity. Here, we report on the development of a redox-active, crystalline, mesoporous covalent organic framework (COF) on carbon nanotubes for use as electrodes; the electrode stability is enhanced by the covalent network, the ion transport is facilitated by the open meso-channels, and the electron conductivity is boosted by the carbon nanotube wires. These effects work synergistically for the storage of energy and provide lithium-ion batteries with high efficiency, robust cycle stability, and high rate capability. Our results suggest that redox-active COFs on conducting carbons could serve as a unique platform for energy storage and may facilitate the design of new organic electrodes for high-performance and environmentally benign battery devices. PMID:25650133

  14. Influence of heterogeneous ammonium availability on bacterial community structure and the expression of nitrogen fixation and ammonium transporter genes during in situ bioremediation of uranium-contaminated groundwater

    SciTech Connect

    Mouser, P.J.; N'Guessan, A.L.; Elifantz, H.; Holmes, D.E.; Williams, K.H.; Wilkins, M.J.; Long, P.E.; Lovley, D.R.

    2009-04-01

    The impact of ammonium availability on microbial community structure and the physiological status and activity of Geobacter species during in situ bioremediation of uranium-contaminated groundwater was evaluated. Ammonium concentrations varied by as much as two orders of magnitude (<4 to 400 {micro}M) across the study site. Analysis of 16S rRNA gene sequences suggested that ammonium influenced the composition of the microbial community prior to acetate addition with Rhodoferax species predominating over Geobacter species at the site with the highest ammonium, and Dechloromonas species dominating at sites with lowest ammonium. However, once acetate was added, and dissimilatory metal reduction was stimulated, Geobacter species became the predominant organisms at all locations. Rates of U(VI) reduction appeared to be more related to the concentration of acetate that was delivered to each location rather than the amount of ammonium available in the groundwater. In situ mRNA transcript abundance of the nitrogen fixation gene, nifD, and the ammonium importer gene, amtB, in Geobacter species indicated that ammonium was the primary source of nitrogen during in situ uranium reduction, and that the abundance of amtB transcripts was inversely correlated to ammonium levels across all sites examined. These results suggest that nifD and amtB expression by subsurface Geobacter species are closely regulated in response to ammonium availability to ensure an adequate supply of nitrogen while conserving cell resources. Thus, quantifying nifD and amtB expression appears to be a useful approach for monitoring the nitrogen-related physiological status of Geobacter species in subsurface environments during bioremediation. This study also emphasizes the need for more detailed analysis of geochemical/physiological interactions at the field scale, in order to adequately model subsurface microbial processes.

  15. Monolithic Nickel (II) Oxide Aerogels Using an Organic Epoxide: The Importance of the Counter Ion

    SciTech Connect

    Gash, A E; Satcher, J H; Simpson, R L

    2004-01-13

    The synthesis and characterization of nickel (II) oxide aerogel materials prepared using the epoxide addition method is described. The addition of the organic epoxide propylene oxide to an ethanolic solution of NiCl{sub 2} 6H{sub 2}O resulted in the formation of an opaque light green monolithic gel and subsequent drying with supercritical CO{sub 2} gave a monolithic aerogel material of the same color. This material has been characterized using powder X-ray diffraction, electron microscopy, elemental analysis, and nitrogen adsorption/desorption analysis. The results indicate that the nickel (II) oxide aerogel has very low bulk density (98 kg/m{sup 3} ({approx}98 %porous)), high surface area (413 m{sup 2}/g), and has a particulate-type aerogel microstructure made up of very fine spherical particles with an open porous network. By comparison, a precipitate of Ni{sub 3}(NO{sub 3}){sub 2}(OH){sub 4} is obtained when the same preparation is attempted with the common Ni(NO{sub 3}){sub 2} 6H{sub 2}O salt as the precursor. The implications of the difference of reactivity of the two different precursors are discussed in the context of the mechanism of gel formation via the epoxide addition method. The synthesis of nickel (II) oxide aerogel, using the epoxide addition method, is especially unique in our experience. It is our first example of the successful preparation of a metal oxide aerogel using a metal divalent metal ion and may have implications for the application of this method to the preparation of aerogels or nanoparticles of other divalent metal oxides. To our knowledge this is the first report of a monolithic pure nickel (II) oxide aerogel materials.

  16. Cobalt- and Cadmium-Based Metal-Organic Frameworks as High-Performance Anodes for Sodium Ion Batteries and Lithium Ion Batteries.

    PubMed

    Dong, Caifu; Xu, Liqiang

    2017-03-01

    Two multifunctional metal-organic frameworks (MOFs) with the same coordination mode, [Co(L)(H2O)]n·2nH2O [defined as "Co(L) MOF"] and [Cd(L)(H2O)]n·2nH2O [defined as "Cd(L) MOF"] (L = 5-aminoisophthalic acid) have been fabricated via a simple and versatile scalable solvothermal approach at 85 °C for 24 h. The relationship between the structure of the electrode materials (especially the coordination water and different metal ions) and the electrochemical properties of MOFs have been investigated for the first time. And then the possible electrochemical mechanisms of the electrodes have been studied and proposed. In addition, MOFs/RGO hybrid materials were prepared via ball milling, which demonstrated better electrochemical performances than those of individual Co(L) MOF and Cd(L) MOF. For example, when Co(L) MOF/RGO was applied as anode for sodium ion batteries (SIBs), it retained 206 mA h g(-1) after 330 cycles at 500 mA g(-1) and 1185 mA h g(-1) could be obtained after 50 cycles at 100 mA g(-1) for lithium-ion batteries (LIBs). The high-discharge capacity, excellent cyclic stability combined with the facile synthesis procedure enable Co(L) MOF- and Cd(L) MOF-based materials to be prospective anode materials for SIBs and LIBs.

  17. Removal of natural organic matter from water using ion-exchange resins and cyclodextrin polyurethanes

    NASA Astrophysics Data System (ADS)

    Nkambule, T. I.; Krause, R. W.; Mamba, B. B.; Haarhoff, J.

    Natural organic matter (NOM) consists of a complex mixture of naturally occurring organic compounds. Although it is not considered toxic by itself, NOM present during water disinfection may result in the formation of disinfection by-products (DBPs), many of which are either carcinogenic or mutagenic. Although it is difficult to completely characterize NOM due to its complex and large structure, a consideration of its structure is necessary for a better understanding of the mechanism of NOM removal from water. In this study, water from the Vaalkop water treatment plant was characterized for its NOM composition by fractionation over ion-exchange resins. Fractionation at different pH with different resins resulted in the isolation of the neutral, basic and acidic fractions of both the hydrophobic and hydrophilic NOM. The hydrophilic basic fraction was found to be the most abundant fraction in the source water. Each of the isolated NOM fractions were percolated through cyclodextrin (CD) polyurethanes, resulting in an adsorption efficiency of between 6% and 33%. The acidic fractions were the most adsorbed fractions by the CD polyurethanes, while the neutral fractions being the least adsorbed. The water samples were then subjected to an ozonation regime at the treatment plant and then fractionated as before. As expected there were decreases of the neutral and basic fractions after ozonation. The application of CD polyurethanes to the fractions after ozonation resulted in a removal efficiency of up to 59%, nearly double that of the non-treated sample. Also, in the case of the ozone pre-treated samples, it was mainly the hydrophilic basic fraction which was removed. All the fractions were subjected to a chlorination test to determine the trihalomethane (THM) formation potential. All six NOM fractions resulted in THM formation, but the hydrophilic basic fraction was found to be the most reactive and formed the highest THM concentration. The effect of the combination of

  18. Revealing surface oxidation on the organic semi-conducting single crystal rubrene with time of flight secondary ion mass spectroscopy.

    PubMed

    Thompson, Robert J; Fearn, Sarah; Tan, Ke Jie; Cramer, Hans George; Kloc, Christian L; Curson, Neil J; Mitrofanov, Oleg

    2013-04-14

    To address the question of surface oxidation in organic electronics the chemical composition at the surface of single crystalline rubrene is spatially profiled and analyzed using Time of Flight - Secondary Ion Mass Spectroscopy (ToF-SIMS). It is seen that a uniform oxide (C42H28O) covers the surface while there is an increased concentration of peroxide (C42H28O2) located at crystallographic defects. By analyzing the effects of different primary ions, temperature and sputtering agents the technique of ToF-SIMS is developed as a valuable tool for the study of chemical composition variance both at and below the surface of organic single crystals. The primary ion beams C60(3+) and Bi3(+) are found to be most appropriate for mass spectroscopy and spatial profiling respectively. Depth profiling of the material is successfully undertaken maintaining the molecular integrity to a depth of ~5 μm using an Ar cluster ion source as the sputtering agent.

  19. Generation and detection of metal ions and volatile organic compounds (VOCs) emissions from the pretreatment processes for recycling spent lithium-ion batteries.

    PubMed

    Li, Jia; Wang, Guangxu; Xu, Zhenming

    2016-06-01

    The recycling of spent lithium-ion batteries brings benefits to both economic and environmental terms, but it can also lead to contaminants in a workshop environment. This study focused on metals, non-metals and volatile organic compounds generated by the discharging and dismantling pretreatment processes which are prerequisite for recycling spent lithium-ion batteries. After discharging in NaCl solution, metal contents in supernate and concentrated liquor were detected. Among results of condition #2, #3, #4 and #5, supernate and concentrated liquor contain high levels of Na, Al, Fe; middle levels of Co, Li, Cu, Ca, Zn; and low levels of Mn, Sn, Cr, Zn, Ba, K, Mg, V. The Hg, Ag, Cr and V are not detected in any of the analyzed supernate. 10wt% NaCl solution was a better discharging condition for high discharge efficiency, less possible harm to environment. To collect the gas released from dismantled LIB belts, a set of gas collecting system devices was designed independently. Two predominant organic vapour compounds were dimethyl carbonate (4.298mgh(-1)) and tert-amylbenzene (0.749mgh(-1)) from one dismantled battery cell. To make sure the concentrations of dimethyl carbonate under recommended industrial exposure limit (REL) of 100mgL(-1), for a workshop on dismantling capacity of 1000kg spent LIBs, the minimum flow rate of ventilating pump should be 235.16m(3)h(-1).

  20. Phase equilibria and distribution constants of metal ions in diantipyryl alkane-organic acid-hydrochloric acid-water systems

    NASA Astrophysics Data System (ADS)

    Degtev, M. I.; Popova, O. N.; Yuminova, A. A.

    2014-08-01

    The ability of antipyrine and its derivatives (diantipyryl alkanes) to form separating systems in the presence of salicylic (sulfosalicylic) acid and hydrochloric acid and water is studied. The optimum volume of the organic phase, the composition of complexes, and the mechanism for the distribution of metal ions are determined, depending on the concentrations of the main components and the salting-out agent. The complex distribution and extraction constants are calculated.

  1. Organic electrolyte-based rechargeable zinc-ion batteries using potassium nickel hexacyanoferrate as a cathode material

    NASA Astrophysics Data System (ADS)

    Chae, Munseok S.; Heo, Jongwook W.; Kwak, Hunho H.; Lee, Hochun; Hong, Seung-Tae

    2017-01-01

    This study demonstrates an organic electrolyte-based rechargeable zinc-ion battery (ZIB) using Prussian blue (PB) analogue potassium nickel hexacyanoferrate K0.86Ni[Fe(CN)6]0.954(H2O)0.766 (KNF-086) as the cathode material. KNF-086 is prepared via electrochemical extraction of potassium ions from K1.51Ni[Fe(CN)6]0.954(H2O)0.766 (KNF-151). The cell is composed of a KNF-086 cathode, a zinc metal anode, and a 0.5 M Zn(ClO4)2 acetonitrile electrolyte. This cell shows a reversible discharge capacity of 55.6 mAh g-1 at 0.2 C rate with the discharge voltage at 1.19 V (vs. Zn2+/Zn). As evidenced by Fourier electron density analysis with powder XRD data, the zinc-inserted phase is confirmed as Zn0.32K0.86Ni[Fe(CN)6]0.954(H2O)0.766 (ZKNF-086), and the position of the zinc ion in ZKNF-086 is revealed as the center of the large interstitial cavities of the cubic PB. Compared to KNF-086, ZKNF-086 exhibits a decreased unit cell parameter (0.9%) and volume (2.8%) while the interatomic distance of d(Fe-C) increased (from 1.84 to 1.98 Å), and the oxidation state of iron decreases from 3 to 2.23. The organic electrolyte system provides higher zinc cycling efficiency (>99.9%) than the aqueous system (ca. 80%). This result demonstrates an organic electrolyte-based ZIB, and offers a crucial basis for understanding the electrochemical intercalation chemistry of zinc ions in organic electrolytes.

  2. A Dual Source Ion Trap Mass Spectrometer for the Mars Organic Molecule Analyzer of ExoMars 2018

    NASA Technical Reports Server (NTRS)

    Brickerhoff, William B.; vanAmerom, F. H. W.; Danell, R. M.; Arevalo, R.; Atanassova, M.; Hovmand, L.; Mahaffy, P. R.; Cotter, R. J.

    2011-01-01

    We present details on the objectives, requirements, design and operational approach of the core mass spectrometer of the Mars Organic Molecule Analyzer (MOMA) investigation on the 2018 ExoMars mission. The MOMA mass spectrometer enables the investigation to fulfill its objective of analyzing the chemical composition of organic compounds in solid samples obtained from the near surface of Mars. Two methods of ionization are realized, associated with different modes of MOMA operation, in a single compact ion trap mass spectrometer. The stringent mass and power constraints of the mission have led to features such as low voltage and low frequency RF operation [1] and pulse counting detection.

  3. Improved electrolytes for Li-ion batteries: Mixtures of ionic liquid and organic electrolyte with enhanced safety and electrochemical performance

    NASA Astrophysics Data System (ADS)

    Guerfi, A.; Dontigny, M.; Charest, P.; Petitclerc, M.; Lagacé, M.; Vijh, A.; Zaghib, K.

    Physical and electrochemical characteristics of Li-ion battery systems based on LiFePO 4 cathodes and graphite anodes with mixture electrolytes were investigated. The mixed electrolytes are based on an ionic liquid (IL), and organic solvents used in commercial batteries. We investigated a range of compositions to determine an optimum conductivity and non-flammability of the mixed electrolyte. This led us to examine mixtures of ILs with the organic electrolyte usually employed in commercial Li-ion batteries, i.e., ethylene carbonate (EC) and diethylene carbonate (DEC). The IL electrolyte consisted of (trifluoromethyl sulfonylimide) (TFSI) as anion and 1-ethyl-3-methyleimidazolium (EMI) as the cation. The physical and electrochemical properties of some of these mixtures showed an improvement characteristics compared to the constituents alone. The safety was improved with electrolyte mixtures; when IL content in the mixture is ≥40%, no flammability is observed. A stable SEI layer was obtained on the MCMB graphite anode in these mixed electrolytes, which is not obtained with IL containing the TFSI-anion. The high-rate capability of LiFePO 4 is similar in the organic electrolyte and the mixture with a composition of 1:1. The interface resistance of the LiFePO 4 cathode is stabilized when the IL is added to the electrolyte. A reversible capacity of 155 mAh g -1 at C/12 is obtained with cells having at least some organic electrolyte compared to only 124 mAh g -1 with pure IL. With increasing discharge rate, the capacity is maintained close to that in the organic solvent up to 2 C rate. At higher rates, the results with mixture electrolytes start to deviate from the pure organic electrolyte cell. The evaluation of the Li-ion cells; LiFePO 4//Li 4Ti 5O 12 with organic and, 40% mixture electrolytes showed good 1st CE at 98.7 and 93.0%, respectively. The power performance of both cell configurations is comparable up to 2 C rate. This study indicates that safety and

  4. Use of mild organic acid reagents to recover the Co and Li from spent Li-ion batteries.

    PubMed

    Nayaka, Girish Praveen; Pai, Karkala Vasantakumar; Manjanna, Jayappa; Keny, Sangita J

    2016-05-01

    New organic acid mixtures have been investigated to recover the valuable metal ions from the cathode material of spent Li-ion batteries. The cathodic active material (LiCoO2) collected from spent Li-ion batteries (LIBs) is dissolved in mild organic acids, iminodiacetic acid (IDA) and maleic acid (MA), to recover the metals. Almost complete dissolution occurred in slightly excess (than the stoichiometric requirement) of IDA or MA at 80°C for 6h, based on the Co and Li released. The reducing agent, ascorbic acid (AA), converts the dissolved Co(III)- to Co(II)-L (L=IDA or MA) thereby selective recovery of Co as Co(II)-oxalate is possible. The formation of Co(III)- and Co(II)-L is evident from the UV-Vis spectra of the dissolved solution as a function of dissolution time. Thus, the reductive-complexing dissolution mechanism is proposed here. These mild organic acids are environmentally benign unlike the mineral acids.

  5. Highly Sensitive and Patchable Pressure Sensors Mimicking Ion-Channel-Engaged Sensory Organs.

    PubMed

    Chun, Kyoung-Yong; Son, Young Jun; Han, Chang-Soo

    2016-04-26

    Biological ion channels have led to much inspiration because of their unique and exquisite operational functions in living cells. Specifically, their extreme and dynamic sensing abilities can be realized by the combination of receptors and nanopores coupled together to construct an ion channel system. In the current study, we demonstrated that artificial ion channel pressure sensors inspired by nature for detecting pressure are highly sensitive and patchable. Our ion channel pressure sensors basically consisted of receptors and nanopore membranes, enabling dynamic current responses to external forces for multiple applications. The ion channel pressure sensors had a sensitivity of ∼5.6 kPa(-1) and a response time of ∼12 ms at a frequency of 1 Hz. The power consumption was recorded as less than a few μW. Moreover, a reliability test showed stability over 10 000 loading-unloading cycles. Additionally, linear regression was performed in terms of temperature, which showed no significant variations, and there were no significant current variations with humidity. The patchable ion channel pressure sensors were then used to detect blood pressure/pulse in humans, and different signals were clearly observed for each person. Additionally, modified ion channel pressure sensors detected complex motions including pressing and folding in a high-pressure range (10-20 kPa).

  6. Method for characterization of low molecular weight organic acids in atmospheric aerosols using ion chromatography mass spectrometry.

    PubMed

    Brent, Lacey C; Reiner, Jessica L; Dickerson, Russell R; Sander, Lane C

    2014-08-05

    The structural composition of PM2.5 monitored in the atmosphere is usually divided by the analysis of organic carbon, black (also called elemental) carbon, and inorganic salts. The characterization of the chemical composition of aerosols represents a significant challenge to analysts, and studies are frequently limited to determination of aerosol bulk properties. To better understand the potential health effects and combined interactions of components in aerosols, a variety of measurement techniques for individual analytes in PM2.5 need to be implemented. The method developed here for the measurement of organic acids achieves class separation of aliphatic monoacids, aliphatic diacids, aromatic acids, and polyacids. The selective ion monitoring capability of a triple quadropole mass analyzer was frequently capable of overcoming instances of incomplete separations. Standard Reference Material (SRM) 1649b Urban Dust was characterized; 34 organic acids were qualitatively identified, and 6 organic acids were quantified.

  7. Single stage biological nitrogen removal by nitritation and anaerobic ammonium oxidation in biofilm systems.

    PubMed

    Helmer, C; Tromm, C; Hippen, A; Rosenwinkel, K H; Seyfried, C F; Kunst, S

    2001-01-01

    In full scale wastewater treatment plants with at times considerable deficits in the nitrogen balances, it could hitherto not be sufficiently explained which reactions are the cause of the nitrogen losses and which micro-organisms participate in the process. The single stage conversion of ammonium into gaseous end-products--which is henceforth referred to as deammonification--occurs particularly frequently in biofilm systems. In the meantime, one has succeeded to establish the deammonification processes in a continuous flow moving-bed pilot plant. In batch tests with the biofilm covered carriers, it was possible for the first time to examine the nitrogen conversion at the intact biofilm. Depending on the dissolved oxygen (DO) concentration, two autotrophic nitrogen converting reactions in the biofilm could be proven: one nitritation process under aerobic conditions and one anaerobic ammonium oxidation. With the anaerobic ammonium oxidation, ammonium as electron donor was converted with nitrite as electron acceptor. The end-product of this reaction was N2. Ammonium and nitrite did react in a stoichiometrical ratio of 1:1.37, a ratio which has in the very same dimension been described for the ANAMMOX-process (1:1.31 +/- 0.06). Via the oxygen concentration in the surrounding medium, it was possible to control the ratio of nitritation and anaerobic ammonium oxidation in the nitrogen conversion of the biofilm. Both processes were evenly balanced at a DO concentration of 0.7 mg/l, so that it was possible to achieve a direct, almost complete elimination of ammonium without addition of nitrite. One part of the provided ammonium did participate in the nitritation, the other in the anaerobic ammonium oxidation. Through the aerobic ammonium oxidation into nitrite within the outer oxygen supplied layers of the biofilm, the reaction partner was produced for the anaerobic ammonium oxidation within the inner layers of the biofilm.

  8. Microwave Hydrothermal Synthesis of Terbium Ions Complexed with Porous Graphene for Effective Absorbent for Organic Dye

    NASA Astrophysics Data System (ADS)

    Chen, Keqin; Gao, Hui; Bai, Bowei; Liu, Wenjing; Li, Xiaolong

    2017-03-01

    A luminescent terbium ions/reduced graphene oxide complex (Tb-RGO) was successfully and rapidly synthesized by the microwave hydrothermal reaction via the interactions between terbium ions and the active oxygen functional groups of graphene oxide. The as-prepared material was porous stacked by multilayer graphene in all directions. Thus, the resulting product owed the high specific surface area, high adsorption capacity and ultra-fast adsorption rate. Combined with the characteristic photoluminescence derived from terbium ions, the material has potential applications in biosensing and environmental protection.

  9. Microwave Hydrothermal Synthesis of Terbium Ions Complexed with Porous Graphene for Effective Absorbent for Organic Dye.

    PubMed

    Chen, Keqin; Gao, Hui; Bai, Bowei; Liu, Wenjing; Li, Xiaolong

    2017-12-01

    A luminescent terbium ions/reduced graphene oxide complex (Tb-RGO) was successfully and rapidly synthesized by the microwave hydrothermal reaction via the interactions between terbium ions and the active oxygen functional groups of graphene oxide. The as-prepared material was porous stacked by multilayer graphene in all directions. Thus, the resulting product owed the high specific surface area, high adsorption capacity and ultra-fast adsorption rate. Combined with the characteristic photoluminescence derived from terbium ions, the material has potential applications in biosensing and environmental protection.

  10. Formation and stabilization of anionic metal complexes in concentrated aqueous quaternary ammonium salt solutions

    SciTech Connect

    Aronson, F.L.; Hwang, L.L.Y.; Ronca, N.; Solomon, N.A.; Steigman, J.

    1985-02-04

    Anionic complexes of transition metals were stabilized in aqueous solutions containing high concentrations of various short-chain quaternary ammonium salts. Compounds with longer paraffin chains were effective in much less concentrated solution. Complex ions were detected spectrophotometrically. FeCl/sub 4//sup -/, which is usually formed in concentrated HCl, was the predominant Fe(III) complex in 30 m choline chloride containing only 0.12 M HCl. A yellow transitory Tc(VII) chloro-addition intermediate, formed in the reduction of TcO/sub 4//sup -/ by concentrated HCl, was stabilized when the solution also contained 25 m choline chloride. Its spectrum, as well as the isolation of an already known Tc(VII) bipyridyl complex, is reported. Concentrated organic electrolytes also stabilized Tc(V) oxide halides against disproportionation and Tc(IV) hexahalides against hydrolysis. Halochromates of Cr(VI) were formed and stabilized in dilute acid containing quaternary ammonium salts. Their UV spectra showed the well-resolved vibronic fine structure associated with the symmetric chromium-to-oxygen charge-transfer band. It is known that these progressions are resolved in aprotic solvents, but not in aqueous acidic solution alone, and that the loss of fine structure in aqueous media is due to hydrogen bonding. The stabilization of anionic metal complexes and the resolution of vibronic structure in halochromates are probably consequences of water-structure-enforced ion paring. The present work suggests that the water molecules in immediate contact with the complex anions are more strongly hydrogen bonded to each other than to the complex. 21 references, 4 figures.

  11. Intercalation of Coordinatively Unsaturated Fe(III) Ion within Interpenetrated Metal-Organic Framework MOF-5.

    PubMed

    Holmberg, Rebecca J; Burns, Thomas; Greer, Samuel M; Kobera, Libor; Stoian, Sebastian A; Korobkov, Ilia; Hill, Stephen; Bryce, David L; Woo, Tom K; Murugesu, Muralee

    2016-06-01

    Coordinatively unsaturated Fe(III) metal sites were successfully incorporated into the iconic MOF-5 framework. This new structure, Fe(III) -iMOF-5, is the first example of an interpenetrated MOF linked through intercalated metal ions. Structural characterization was performed with single-crystal and powder XRD, followed by extensive analysis by spectroscopic methods and solid-state NMR, which reveals the paramagnetic ion through its interaction with the framework. EPR and Mössbauer spectroscopy confirmed that the intercalated ions were indeed Fe(III) , whereas DFT calculations were employed to ascertain the unique pentacoordinate architecture around the Fe(III) ion. Interestingly, this is also the first crystallographic evidence of pentacoordinate Zn(II) within the MOF-5 SBU. This new MOF structure displays the potential for metal-site addition as a framework connector, thus creating further opportunity for the innovative development of new MOF materials.

  12. Ammonium removal from aqueous solutions by using natural Chinese (Chende) zeolite as adsorbent.

    PubMed

    Huang, Haiming; Xiao, Xianming; Yan, Bo; Yang, Liping

    2010-03-15

    This paper presents a study of the removal of ammonium ion from aqueous solutions using natural Chinese (Chende) zeolite. A series of experiments was conducted to examine the effects of solution pH, particle size, contact time, adsorbent dosage, and the presence of other cation- and anion species on ammonium removal. The findings indicated that these parameters named had a significant effect on the removal of ammonium by the zeolite. The effect of other cations on the removal of ammonium followed the order of preference Na(+)>K(+)>Ca(2+)>Mg(2+) at identical mass concentrations, and the effect of the presence of individual anions followed the order of preference carbonate>chloride>sulfate>phosphate at identical mass concentrations of ammonium ions. Kinetic analysis showed that the adsorption of ammonium on zeolite at different ranges of particle size well followed the pseudo-second-order model and followed the intra-particle diffusion model only during the initial 60 min of the adsorption process. Equilibrium isotherm data was fitted to the linear Langmuir- and Freundlich models with the latter model providing the better description of the process (R(2)=0.991-0.997) compared to the former (R(2)=0.902-0.989).

  13. Selectivity of externally facing ion-binding sites in the Na/K pump to alkali metals and organic cations.

    PubMed

    Ratheal, Ian M; Virgin, Gail K; Yu, Haibo; Roux, Benoît; Gatto, Craig; Artigas, Pablo

    2010-10-26

    The Na/K pump is a P-type ATPase that exchanges three intracellular Na(+) ions for two extracellular K(+) ions through the plasmalemma of nearly all animal cells. The mechanisms involved in cation selection by the pump's ion-binding sites (site I and site II bind either Na(+) or K(+); site III binds only Na(+)) are poorly understood. We studied cation selectivity by outward-facing sites (high K(+) affinity) of Na/K pumps expressed in Xenopus oocytes, under voltage clamp. Guanidinium(+), methylguanidinium(+), and aminoguanidinium(+) produced two phenomena possibly reflecting actions at site III: (i) voltage-dependent inhibition (VDI) of outwardly directed pump current at saturating K(+), and (ii) induction of pump-mediated, guanidinium-derivative-carried inward current at negative potentials without Na(+) and K(+). In contrast, formamidinium(+) and acetamidinium(+) induced K(+)-like outward currents. Measurement of ouabain-sensitive ATPase activity and radiolabeled cation uptake confirmed that these cations are external K(+) congeners. Molecular dynamics simulations indicate that bound organic cations induce minor distortion of the binding sites. Among tested metals, only Li(+) induced Na(+)-like VDI, whereas all metals tested except Na(+) induced K(+)-like outward currents. Pump-mediated K(+)-like organic cation transport challenges the concept of rigid structural models in which ion specificity at site I and site II arises from a precise and unique arrangement of coordinating ligands. Furthermore, actions by guanidinium(+) derivatives suggest that Na(+) binds to site III in a hydrated form and that the inward current observed without external Na(+) and K(+) represents cation transport when normal occlusion at sites I and II is impaired. These results provide insights on external ion selectivity at the three binding sites.

  14. Ammonium assimilation: An important accessory during aerobic denitrification of Pseudomonas stutzeri T13.

    PubMed

    Sun, Yilu; Feng, Liang; Li, Ang; Zhang, Xuening; Yang, Jixian; Ma, Fang

    2017-03-12

    The present study investigated effect of ammonium utilization on aerobic denitrification by Pseudomonas stutzeri T13. Per nitrogen balance calculation, all consumed ammonium was utilized as nitrogen source for cell propagation by assimilation rather than heterotrophic nitrification. Total organic carbon (TOC) and ammonium were necessary substrates to sustain heterotrophic propagation of P. stutzeri T13 at optimum proportion equal to seven. Under aerobic condition, nitrate was utilized as substitute nitrogen source when ammonium was completely exhausted. Biomass production effectively increased with increasing initial ammonium from 0mg/L to 100mg/L. Owing to enlarged biomass, average nitrate reduction rate increased from 7.36mgL(-1)h(-1) to 11.95mgL(-1)h(-1). Such process also successfully reduced nitrite accumulation from 121.8mg/L to 66.16mg/L during aerobic denitrification. As important accessory during aerobic denitrification, ammonium assimilation efficiently doubled total nitrogen (TN) removal from 54.97mg/L (no ammonium provided) to 113.1mg/L (100mg/L ammonium involved).

  15. Microbial nitrate-dependent cyclohexane degradation coupled with anaerobic ammonium oxidation.

    PubMed

    Musat, Florin; Wilkes, Heinz; Behrends, Astrid; Woebken, Dagmar; Widdel, Friedrich

    2010-10-01

    An anaerobic nitrate-reducing enrichment culture was established with a cyclic saturated petroleum hydrocarbon, cyclohexane, the fate of which in anoxic environments has been scarcely investigated. GC-MS showed cyclohexylsuccinate as a metabolite, in accordance with an anaerobic enzymatic activation of cyclohexane by carbon-carbon addition to fumarate. Furthermore, long-chain cyclohexyl-substituted cell fatty acids apparently derived from cyclohexane were detected. Nitrate reduction was not only associated with cyclohexane utilization but also with striking depletion of added ammonium ions. Significantly more ammonium was consumed than could be accounted for by assimilation. This indicated the occurrence of anaerobic ammonium oxidation (anammox) with nitrite from cyclohexane-dependent nitrate reduction. Indeed, nitrite depletion was stimulated upon further addition of ammonium. Analysis of 16S rRNA genes and subsequent cell hybridization with specific probes showed that approximately 75% of the bacterial cells affiliated with the Geobacteraceae and approximately 18% with Candidatus 'Brocadia anammoxidans' (member of the Planctomycetales), an anaerobic ammonium oxidizer. These results and additional quantitative growth experiments indicated that the member of the Geobacteraceae reduced nitrate with cyclohexane to nitrite and some ammonium; the latter two and ammonium added to the medium were scavenged by anammox bacteria to yield dinitrogen. A model was established to quantify the partition of each microorganism in the overall process. Such hydrocarbon oxidation by an alleged 'denitrification' ('pseudo-denitrification'), which in reality is a dissimilatory loop through anammox, can in principle also occur in other microbial systems with nitrate-dependent hydrocarbon attenuation.

  16. Paleosols in central Illinois as potential sources of ammonium in groundwater

    USGS Publications Warehouse

    Glessner, J.J.G.; Roy, W.R.

    2009-01-01

    Glacially buried paleosols of pre-Holocene age were evaluated as potential sources for anomalously large concentrations of ammonium in groundwater in East Central Illinois. Ammonium has been detected at concentrations that are problematic to water treatment facilities (greater than 2.0 mg/L) in this region. Paleosols characterized for this study were of Quaternary age, specifically Robein Silt samples. Paleosol samples displayed significant capacity to both store and release ammonium through experiments measuring processes of sorption, ion exchange, and weathering. Bacteria and fungi within paleosols may significantly facilitate the leaching of ammonium into groundwater by the processes of assimilation and mineralization. Bacterial genetic material (DNA) was successfully extracted from the Robein Silt, purified, and amplified by polymerase chain reaction to produce 16S rRNA terminal restriction fragment length polymorphism (TRFLP) community analyses. The Robein Silt was found to have established diverse and viable bacterial communities. 16S rRNA TRFLP comparisons to well-known bacterial species yielded possible matches with facultative chemolithotrophs, cellulose consumers, nitrate reducers, and actinomycetes. It was concluded that the Robein Silt is both a source and reservoir for groundwater ammonium. Therefore, the occurrence of relatively large concentrations of ammonium in groundwater monitoring data may not necessarily be an indication of only anthropogenic contamination. The results of this study, however, need to be placed in a hydrological context to better understand whether paleosols can be a significant source of ammonium to drinking water supplies. ?? 2009 National Ground Water Association.

  17. High irradiance improves ammonium tolerance in wheat plants by increasing N assimilation.

    PubMed

    Setién, Igor; Fuertes-Mendizabal, Teresa; González, Azucena; Aparicio-Tejo, Pedro Ma; González-Murua, Carmen; González-Moro, María Begoña; Estavillo, José María

    2013-05-15

    Ammonium is a paradoxical nutrient ion. Despite being a common intermediate in plant metabolism whose oxidation state eliminates the need for its reduction in the plant cell, as occurs with nitrate, it can also result in toxicity symptoms. Several authors have reported that carbon enrichment in the root zone enhances the synthesis of carbon skeletons and, accordingly, increases the capacity for ammonium assimilation. In this work, we examined the hypothesis that increasing the photosynthetic photon flux density is a way to increase plant ammonium tolerance. Wheat plants were grown in a hydroponic system with two different N sources (10mM nitrate or 10mM ammonium) and with two different light intensity conditions (300 μmol photon m(-2)s(-1) and 700 μmol photon m(-2)s(-1)). The results show that, with respect to biomass yield, photosynthetic rate, shoot:root ratio and the root N isotopic signature, wheat behaves as a sensitive species to ammonium nutrition at the low light intensity, while at the high intensity, its tolerance is improved. This improvement is a consequence of a higher ammonium assimilation rate, as reflected by the higher amounts of amino acids and protein accumulated mainly in the roots, which was supported by higher tricarboxylic acid cycle activity. Glutamate dehydrogenase was a key root enzyme involved in the tolerance to ammonium, while glutamine synthetase activity was low and might not be enough for its assimilation.

  18. Electronic control of Ca2+ signalling in neuronal cells using an organic electronic ion pump.

    PubMed

    Isaksson, Joakim; Kjäll, Peter; Nilsson, David; Robinson, Nathaniel D; Berggren, Magnus; Richter-Dahlfors, Agneta

    2007-09-01

    Cells and tissues use finely regulated ion fluxes for their intra- and intercellular communication. Technologies providing spatial and temporal control for studies of such fluxes are however, limited. We have developed an electrophoretic ion pump made of poly(3,4-ethylenedioxythiophene) doped with poly(styrene sulphonate) (PEDOT:PSS) to mediate electronic control of the ion homeostasis in neurons. Ion delivery from a source reservoir to a receiving electrolyte via a PEDOT:PSS thin-film channel was achieved by electronic addressing. Ions are delivered in high quantities at an associated on/off ratio exceeding 300. This induces physiological signalling events that can be recorded at the single-cell level. Furthermore, miniaturization of the device to a 50-microm-wide channel allows for stimulation of individual cells. As this technology platform allows for electronic control of ion signalling in individual cells with proper spatial and temporal resolution, it will be useful in further studies of communication in biological systems.

  19. Mars Organic Molecule Analyzer (MOMA) Mass Spectrometer Flight Model and Future Ion Trap-Based Planetary Instruments

    NASA Astrophysics Data System (ADS)

    Brinckerhoff, W. B.; van Amerom, F. H. W.; Danell, R.; Pinnick, V. T.; Arevalo, R. D., Jr.; Li, X.; Grubisic, A.; Getty, S.; Hovmand, L.; Mahaffy, P. R.

    2015-12-01

    The Mars Organic Molecule Analyzer (MOMA) investigation on the 2018 ExoMars rover will examine the chemical composition of samples acquired from depths of up to two meters below the martian surface, where organics may be protected from radiative and oxidative degradation. MOMA combines pyrolysis gas chromatography mass spectrometry (GCMS) of bulk powder samples and Mars ambient laser desorption mass spectrometry (LDMS) surface analysis, using a single ion trap MS. This dual source design enables MOMA to detect compounds over a wide range of molecular weights and volatilities. The structure of any detected organics may be further examined using MOMA's tandem mass spectrometry (MS/MS) mode. The flight model (FM) ion trap sensor and electronics have been assembled under the extremely clean and sterile conditions required by ExoMars, and have met or exceeded all performance specifications during initial functional tests. After Mars ambient thermal cycling and calibration, the FM will be delivered as a subsystem of MOMA to rover integration in mid-2016. There MOMA will join complementary rover instruments such as the Raman and MicrOmega spectrometers designed to analyze common drill samples. Following the MOMA design, linear ion trap mass spectrometer (LITMS)-based instruments are under development for future missions. LITMS adds enhanced capabilities such as precision (point-by-point) analysis of drill cores, negative ion detection, a wider mass range, and higher temperature pyrolysis with precision evolved gas analysis, while remaining highly compact and robust. Each of the capabilities of LITMS has been demonstrated on breadboard hardware. The next phase will realize an end-to-end brassboard at flight scale that will meet stringent technology readiness level (TRL) 6 criteria, indicating readiness for development toward missions to Mars, comets, asteroids, outer solar system moons, and beyond.

  20. Properties of the Nafion membrane impregnated with hydroxyl ammonium based ionic liquids

    NASA Astrophysics Data System (ADS)

    Garaev, Valeriy; Kleperis, Janis; Pavlovica, Sanita; Vaivars, Guntars

    2012-08-01

    In this work, the Nafion 112 membrane impregnated with nine various hydroxyl ammonium based ionic liquids have been investigated. The used ionic liquids were combined from hydroxyl ammonium cations (2-hydroxyethylammonium/HEA, bis(2- hydroxyethyl)ammonium/BHEA, tris(2-hydroxyethyl)ammonium/THEA) and carboxylate anions (formate, acetate, lactate). The membranes are characterized by conductivity and thermal stability measurements. It was found, that almost all composites have 10 times higher ion conductivity than a pure Nafion 112 at 90 °C in ambient environment due to the higher thermal stability. The thermal stability of Nafion membrane was increased by all studied nine ionic liquids. In this work, only biodegradable ionic liquids were used for composite preparation.

  1. Treatment of ammonium-rich swine waste in modified porphyritic andesite fixed-bed anaerobic bioreactor.

    PubMed

    Wang, Qinghong; Yang, Yingnan; Li, Dawei; Feng, Chuanping; Zhang, Zhenya

    2012-05-01

    In this study, a modified porphyritic andesite (WRS) was developed as ammonium adsorbent and bed material for the anaerobic digestion of ammonium-rich swine waste. The performance in bioreactors with modified WRS, natural WRS, calcium chloride and no additives was investigated. The bioreactor with modified WRS exhibited the best performance, with start-up time on the 7th day, methane yield of 359.71 ml/g-VS, and COD removal of 67.99% during all 44 days of the experiment at 35°C. The effective ammonium adsorption and essential ions dissociation for microorganisms by modified WRS, as well as the immobilization of microbial on the surface of the modified WRS play a great role on the high efficiency anaerobic digestion of ammonium-rich swine waste.

  2. Salting out of proteins using ammonium sulfate precipitation.

    PubMed

    Duong-Ly, Krisna C; Gabelli, Sandra B

    2014-01-01

    Protein solubility is affected by ions. At low ion concentrations (<0.5 M), protein solubility increases along with ionic strength. Ions in the solution shield protein molecules from the charge of other protein molecules in what is known as 'salting-in'. At a very high ionic strength, protein solubility decreases as ionic strength increases in the process known as 'salting-out'. Thus, salting out can be used to separate proteins based on their solubility in the presence of a high concentration of salt. In this protocol, ammonium sulfate will be added incrementally to an E. coli cell lysate to isolate a recombinantly over-expressed protein of 20 kDa containing no cysteine residues or tags.

  3. Redox potentials in ammonium nitrate solutions

    SciTech Connect

    Ngameni, E.; Ammaa, B.B.; Wandji, R.; Bessiere, J.

    1995-03-01

    The redox potentials of M{sup n+}/M (M{sup n+} = Cu{sup 2+}, Pb{sup 2+}, Sn{sup 2+}, Cd{sup 2+}, Ag{sup +}, Zn{sup 2+}, Hg{sup 2+}), M{sup n+}/M {sup (n{minus}m)+} (Fe{sup 3+}/Fe{sup 2+}, Fe(CN){sub 6}3{minus}/Fe(CN){sub 6}{sup 4{minus}}), and AgX/Ag, X{sup {minus}} (X = Cl, Br, and I) have been measured in aqueous solutions of ammonium nitrate (1--14 M). The variation of salvation of ions, characterized by the solvent transfer coefficient f{sup tr}, is calculated from the normal redox potentials of the systems. For all the cases, the potential of the ferricinium/ferrocene system (Fe{sup +}/Fc) is used as a reference of potential. It appears as a general trend that when the concentration of salt increases from 1 to 14 M, the potentials of the systems vary slightly, indicating weak interactions between these solutes and the salt. The examined ions can be classified into two groups: those that are less solvated as the concentration of NH{sub 4}NO{sub 3} increases (CU{sup 2+}, Cd{sup 2+}, Zn{sup 2+}, Cl{sup {minus}}, Br{sup {minus}}, I{sup {minus}}) and those that are more solvated, (Pb{sup 2+}, Ag{sup +}, Hg{sup 2+}, Sn{sup 2+}). The solubility constants of the AgX salts in the H{sub 2}O + NH{sub 4}NO{sub 3} mixtures are also calculated.

  4. Analytical techniques for determining bound ammonium

    SciTech Connect

    Altaner, S.P.; Krohn, M.D

    1985-01-01

    Ammonium (NH/sub 4//sup +/) has been found to substitute for alkali cations in feldspars, micas, smectites, and alunites several Hg/Au-bearing hot springs deposits and volcanogenic stratabound Pb/Zn deposits. The authors compared four analytical techniques for determining the NH/sub 4//sup +/ content in rocks from these types of deposit and in synthetic NH/sub 4//sup +/-bearing feldspars, micas, and alunites: 1) X-ray diffraction (XRD), 2) mid- and 3) near-infrared spectroscopy (MIR and NIR) and 4) ion chromatography (IC). MIR analysis of synthetic minerals indicates that 7 ..mu..m band depth depends upon mineral type but that, for a given mineral, band depth is directly proportional to NH/sub 4//sup +/ concentration. NIR reflectance spectroscopy gives a rapid qualitative determination of NH/sub 4//sup +/ and allows positive field identification of NH/sub 4//sup +/. 4) IC gives a measure of the percent of NH/sub 4//sup +/ substitution by determining NH/sub 4//sup +/, K/sup +/, and Na/sup +/ concentrations. The procedure involves sample dissolution by HCl and HF in a microwave oven followed by separation and detection by an ion chromatograph. They estimate the detection limits of these analytical techniques for NH/sub 4//sup +/ concentration to be: XRD, 10-20% NH/sub 4//sup +/; MIR, 1-5% NG/sub 4//sup +/; and IC, <1% NH/sub 4//sup +/. Determination of NH/sub 4//sup +/ abundance in rocks will help to delineate the relationship of NH/sub 4//sup +/-bearing minerals to mineralization in ore deposits and promises to be an excellent method for prospecting.

  5. Selective fluorescence sensors for detection of nitroaniline and metal Ions based on ligand-based luminescent metal-organic frameworks

    SciTech Connect

    Yu, Zongchao; Wang, Fengqin; Lin, Xiangyi; Wang, Chengmiao; Fu, Yiyuan; Wang, Xiaojun; Zhao, Yongnan; Li, Guodong

    2015-12-15

    Metal-organic frameworks (MOFs) are porous crystalline materials with high potential for applications in fluorescence sensors. In this work, two solvent-induced Zn(II)–based metal-organic frameworks, Zn{sub 3}L{sub 3}(DMF){sub 2} (1) and Zn{sub 3}L{sub 3}(DMA){sub 2}(H{sub 2}O){sub 3} (2) (L=4,4′-stilbenedicarboxylic acid), were investigated as selective sensing materials for detection of nitroaromatic compounds and metal ions. The sensing experiments show that 1 and 2 both exhibit selective fluorescence quenching toward nitroaniline with a low detection limit. In addition, 1 exhibits high selectivity for detection of Fe{sup 3+} and Al{sup 3+} by significant fluorescence quenching or enhancement effect. While for 2, it only exhibits significant fluorescence quenching effect for Fe{sup 3+}. The results indicate that 1 and 2 are both promising fluorescence sensors for detecting and recognizing nitroaniline and metal ions with high sensitivity and selectivity. - Graphical abstract: Two MOFs have been selected as the fluorescence sensing materials for selectively sensing mitroaromatic compounds and metal ions. The high selectivity makes them promising fluorescence sensors for detecting and recognizing nitroaniline and Fe{sup 3+} or Al{sup 3+}.

  6. Influence of organic ions on DNA damage induced by 1 eV to 60 keV electrons.

    PubMed

    Zheng, Yi; Sanche, Léon

    2010-10-21

    We report the results of a study on the influence of organic salts on the induction of single strand breaks (SSBs) and double strand breaks (DSBs) in DNA by electrons of 1 eV to 60 keV. Plasmid DNA films are prepared with two different concentrations of organic salts, by varying the amount of the TE buffer (Tris-HCl and EDTA) in the films with ratio of 1:1 and 6:1 Tris ions to DNA nucleotide. The films are bombarded with electrons of 1, 10, 100, and 60 000 eV under vacuum. The damage to the 3197 base-pair plasmid is analyzed ex vacuo by agarose gel electrophoresis. The highest yields are reached at 100 eV and the lowest ones at 60 keV. The ratios of SSB to DSB are surprisingly low at 10 eV (∼4.3) at both salt concentrations, and comparable to the ratios measured with 100 eV electrons. At all characteristic electron energies, the yields of SSB and DSB are found to be higher for the DNA having the lowest salt concentration. However, the organic salts are more efficient at protecting DNA against the damage induced by 1 and 10 eV electrons. DNA damage and protection by organic ions are discussed in terms of mechanisms operative at each electron energy. It is suggested that these ions create additional electric fields within the groove of DNA, which modify the resonance parameter of 1 and 10 eV electrons, namely, by reducing the electron capture cross-section of basic DNA units and the lifetime of corresponding transient anions. An interstrand electron transfer mechanism is proposed to explain the low ratios for the yields of SSB to those of DSB produced by 10 eV electrons.

  7. Influence of organic ions on DNA damage induced by 1 eV to 60 keV electrons

    SciTech Connect

    Zheng Yi; Sanche, Leon

    2010-10-21

    We report the results of a study on the influence of organic salts on the induction of single strand breaks (SSBs) and double strand breaks (DSBs) in DNA by electrons of 1 eV to 60 keV. Plasmid DNA films are prepared with two different concentrations of organic salts, by varying the amount of the TE buffer (Tris-HCl and EDTA) in the films with ratio of 1:1 and 6:1 Tris ions to DNA nucleotide. The films are bombarded with electrons of 1, 10, 100, and 60 000 eV under vacuum. The damage to the 3197 base-pair plasmid is analyzed ex vacuo by agarose gel electrophoresis. The highest yields are reached at 100 eV and the lowest ones at 60 keV. The ratios of SSB to DSB are surprisingly low at 10 eV ({approx}4.3) at both salt concentrations, and comparable to the ratios measured with 100 eV electrons. At all characteristic electron energies, the yields of SSB and DSB are found to be higher for the DNA having the lowest salt concentration. However, the organic salts are more efficient at protecting DNA against the damage induced by 1 and 10 eV electrons. DNA damage and protection by organic ions are discussed in terms of mechanisms operative at each electron energy. It is suggested that these ions create additional electric fields within the groove of DNA, which modify the resonance parameter of 1 and 10 eV electrons, namely, by reducing the electron capture cross-section of basic DNA units and the lifetime of corresponding transient anions. An interstrand electron transfer mechanism is proposed to explain the low ratios for the yields of SSB to those of DSB produced by 10 eV electrons.

  8. Influence of organic ions on DNA damage induced by 1 eV to 60 keV electrons

    NASA Astrophysics Data System (ADS)

    Zheng, Yi; Sanche, Léon

    2010-10-01

    We report the results of a study on the influence of organic salts on the induction of single strand breaks (SSBs) and double strand breaks (DSBs) in DNA by electrons of 1 eV to 60 keV. Plasmid DNA films are prepared with two different concentrations of organic salts, by varying the amount of the TE buffer (Tris-HCl and EDTA) in the films with ratio of 1:1 and 6:1 Tris ions to DNA nucleotide. The films are bombarded with electrons of 1, 10, 100, and 60 000 eV under vacuum. The damage to the 3197 base-pair plasmid is analyzed ex vacuo by agarose gel electrophoresis. The highest yields are reached at 100 eV and the lowest ones at 60 keV. The ratios of SSB to DSB are surprisingly low at 10 eV (˜4.3) at both salt concentrations, and comparable to the ratios measured with 100 eV electrons. At all characteristic electron energies, the yields of SSB and DSB are found to be higher for the DNA having the lowest salt concentration. However, the organic salts are more efficient at protecting DNA against the damage induced by 1 and 10 eV electrons. DNA damage and protection by organic ions are discussed in terms of mechanisms operative at each electron energy. It is suggested that these ions create additional electric fields within the groove of DNA, which modify the resonance parameter of 1 and 10 eV electrons, namely, by reducing the electron capture cross-section of basic DNA units and the lifetime of corresponding transient anions. An interstrand electron transfer mechanism is proposed to explain the low ratios for the yields of SSB to those of DSB produced by 10 eV electrons.

  9. A Safer Sodium‐Ion Battery Based on Nonflammable Organic Phosphate Electrolyte

    PubMed Central

    Zeng, Ziqi; Jiang, Xiaoyu; Li, Ran; Yuan, Dingding; Ai, Xinping; Yang, Hanxi

    2016-01-01

    Sodium‐ion batteries are now considered as a low‐cost alternative to lithium‐ion technologies for large‐scale energy storage applications; however, their safety is still a matter of great concern for practical applications. In this paper, a safer sodium‐ion battery is proposed by introducing a nonflammable phosphate electrolyte (trimethyl phosphate, TMP) coupled with NaNi0.35Mn0.35Fe0.3O2 cathode and Sb‐based alloy anode. The physical and electrochemical compatibilities of the TMP electrolyte are investigated by igniting, ionic conductivity, cyclic voltammetry, and charge–discharge measurements. The results exhibit that the TMP electrolyte with FEC additive is completely nonflammable and has wide electrochemical window (0–4.5 V vs. Na/Na+), in which both the Sb‐based anode and NaNi0.35Mn0.35Fe0.3O2 cathode show high reversible capacity and cycling stability, similarly as in carbonate electrolyte. Based on these results, a nonflammable sodium‐ion battery is constructed by use of Sb anode, NaNi0.35Mn0.35Fe0.3O2 cathode, and TMP + 10 vol% FEC electrolyte, which works very well with considerable capacity and cyclability, demonstrating a promising prospect to build safer sodium‐ion batteries for large‐scale energy storage applications. PMID:27711263

  10. A Safer Sodium-Ion Battery Based on Nonflammable Organic Phosphate Electrolyte.

    PubMed

    Zeng, Ziqi; Jiang, Xiaoyu; Li, Ran; Yuan, Dingding; Ai, Xinping; Yang, Hanxi; Cao, Yuliang

    2016-09-01

    Sodium-ion batteries are now considered as a low-cost alternative to lithium-ion technologies for large-scale energy storage applications; however, their safety is still a matter of great concern for practical applications. In this paper, a safer sodium-ion battery is proposed by introducing a nonflammable phosphate electrolyte (trimethyl phosphate, TMP) coupled with NaNi0.35Mn0.35Fe0.3O2 cathode and Sb-based alloy anode. The physical and electrochemical compatibilities of the TMP electrolyte are investigated by igniting, ionic conductivity, cyclic voltammetry, and charge-discharge measurements. The results exhibit that the TMP electrolyte with FEC additive is completely nonflammable and has wide electrochemical window (0-4.5 V vs. Na/Na(+)), in which both the Sb-based anode and NaNi0.35Mn0.35Fe0.3O2 cathode show high reversible capacity and cycling stability, similarly as in carbonate electrolyte. Based on these results, a nonflammable sodium-ion battery is constructed by use of Sb anode, NaNi0.35Mn0.35Fe0.3O2 cathode, and TMP + 10 vol% FEC electrolyte, which works very well with considerable capacity and cyclability, demonstrating a promising prospect to build safer sodium-ion batteries for large-scale energy storage applications.

  11. Is sputtering relevant for ion-induced self-organized pattern formation?

    NASA Astrophysics Data System (ADS)

    Hofsäss, Hans; Bobes, Omar; Zhang, Kun

    2013-04-01

    Recently it was reported that ion-induced mass redistribution rather than sputtering would solely determine ripple pattern formation of ion-irradiated surfaces. We investigate the pattern formation on Si irradiated with Xe ions with energies of 5 and 10 keV. Sputter yield and collision cascade characteristics vary strongly as function of ion energy, ion mass and substrate material and allow us to investigate the contributions of curvature dependent erosion as well as mass redistribution. The experimental results are compared with calculations of the curvature coefficients Sx and Sy. Parameters required for the calculations are extracted from Monte Carlo simulations with program SDTrimSP. The calculated curvature coefficients show that mass redistribution is dominant for parallel ripple formation in most cases. The angle where the pattern orientation changes from parallel to perpendicular ripples is however related to curvature dependent sputtering. We discuss the possibilities to tune the different contributions to pattern formation and examine the possibility to completely eliminate mass redistribution effects.

  12. Behavior of transplutonium elements on ion-exchange materials in mixed aqueous-organic solutions of mineral acids

    SciTech Connect

    Guseva, L.I.; Tikhomirov, G.S.; Stepushkina, V.V.

    1987-03-01

    Systematic studies are reported on the behavior of transplutonium elements (TPE) on cation-exchange and anion-exchange materials in mixed aqueous-organic solutions of mineral acids (HClO/sub 4/, HCl, HNO/sub 3/, H/sub 2/SO/sub 4/, H/sub 3/PO/sub 4/) as affected by solution composition, nature of acid, and nature of organic solvent. With all these acids, replacing most of the water by alcohol increases the TPE uptake on the ion exchangers, and the effect occurs for the cation exchangers at lower contents of the organic component. Optimum conditions have been identified for concentrating and separating TPE from numerous elements. The most effective system consists of anion exchanger with HNO/sub 3/ and alcohol.

  13. 33 CFR 126.28 - Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate; general provisions. 126.28 Section 126...) WATERFRONT FACILITIES HANDLING OF DANGEROUS CARGO AT WATERFRONT FACILITIES § 126.28 Ammonium...

  14. 33 CFR 126.28 - Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate; general provisions. 126.28 Section 126...) WATERFRONT FACILITIES HANDLING OF DANGEROUS CARGO AT WATERFRONT FACILITIES § 126.28 Ammonium...

  15. 49 CFR 176.410 - Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 2 2014-10-01 2014-10-01 false Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures. 176.410 Section 176.410 Transportation Other Regulations Relating to... nitrate and ammonium nitrate mixtures. (a) This section prescribes requirements to be observed...

  16. 33 CFR 126.28 - Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate; general provisions. 126.28 Section 126...) WATERFRONT FACILITIES HANDLING OF DANGEROUS CARGO AT WATERFRONT FACILITIES § 126.28 Ammonium...

  17. 49 CFR 176.410 - Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 2 2011-10-01 2011-10-01 false Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures. 176.410 Section 176.410 Transportation Other Regulations Relating to... nitrate and ammonium nitrate mixtures. (a) This section prescribes requirements to be observed...

  18. 49 CFR 176.410 - Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 2 2013-10-01 2013-10-01 false Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures. 176.410 Section 176.410 Transportation Other Regulations Relating to... nitrate and ammonium nitrate mixtures. (a) This section prescribes requirements to be observed...

  19. 33 CFR 126.28 - Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate; general provisions. 126.28 Section 126...) WATERFRONT FACILITIES HANDLING OF DANGEROUS CARGO AT WATERFRONT FACILITIES § 126.28 Ammonium...

  20. 49 CFR 176.410 - Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 2 2012-10-01 2012-10-01 false Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures. 176.410 Section 176.410 Transportation Other Regulations Relating to... nitrate and ammonium nitrate mixtures. (a) This section prescribes requirements to be observed...

  1. 49 CFR 176.410 - Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures. 176.410 Section 176.410 Transportation Other Regulations Relating to... nitrate and ammonium nitrate mixtures. (a) This section prescribes requirements to be observed...

  2. 33 CFR 126.28 - Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate; general provisions. 126.28 Section 126...) WATERFRONT FACILITIES HANDLING OF DANGEROUS CARGO AT WATERFRONT FACILITIES § 126.28 Ammonium...

  3. Advanced Resolution Organic Molecule Analyzer (AROMA): Simulations, Development and Initial Testing of a Linear Ion Trap-Orbitrap Instrument for Space

    NASA Astrophysics Data System (ADS)

    Arevalo, R.; Danell, R. M.; Gundersen, C.; Hovmand, L.; Southard, A.; Tan, F.; Grubisic, A.; Brinckerhoff, W. B.; Getty, S. A.; Mahaffy, P.; Cottin, H.; Briois, C.; Colin, F.; Szopa, C.; Vuitton, V.; Makarov, A.; Reinhardt-Szyba, M.

    2016-10-01

    AROMA combines a linear ion trap and Orbitrap mass analyzer to enable: quantitative measurements of organic and inorganic compounds; selective isolation of targeted mass ranges; tandem mass spectrometry; and, ultrahigh mass resolution and accuracy.

  4. Polyclonal antibodies mediated immobilization of a peroxidase from ammonium sulphate fractionated bitter gourd (Momordica charantia) proteins.

    PubMed

    Fatima, Aiman; Husain, Qayyum

    2007-06-01

    Polyclonal antibody bound Sepharose 4B support has been exploited for the immobilization of bitter gourd peroxidase directly from ammonium sulphate precipitated proteins. Immunoaffinity immobilized bitter gourd peroxidase exhibited high yield of immobilization. IgG-Sepharose 4B bound bitter gourd peroxidase showed a higher stability against heat, chaotropic agents (urea and guanidinium chloride), detergents (cetyl trimethyl ammonium bromide and Surf Excel), proteolytic enzyme (trypsin) and water-miscible organic solvents (propanol, THF and dioxane). The activity of immobilized bitter gourd peroxidase was significantly enhanced in the presence of cetyl trimethyl ammonium bromide and after treatment with trypsin as compared to soluble enzyme.

  5. Adsorption and Assembly of Ions and Organic Molecules at Electrochemical Interfaces: Nanoscale Aspects

    NASA Astrophysics Data System (ADS)

    Yoshimoto, Soichiro; Itaya, Kingo

    2013-06-01

    We describe the history of electrochemical scanning tunneling microscopy (STM) and advances made in this field during the past 20 years. In situ STM allows one to monitor various electrode processes, such as the underpotential deposition of copper and silver ions; the specific adsorption of iodine and sulfate/bisulfate ions; electrochemical dissolution processes of silicon and gold single-crystal surfaces in electrolyte solutions; and the molecular assembly of metalloporphyrins, metallophthalocyanines, and fullerenes, at atomic and/or molecular resolution. Furthermore, a laser confocal microscope, combined with a differential interference contrast microscope, enables investigation of the dynamics of electrochemical processes at atomic resolution.

  6. Adsorption and assembly of ions and organic molecules at electrochemical interfaces: nanoscale aspects.

    PubMed

    Yoshimoto, Soichiro; Itaya, Kingo

    2013-01-01

    We describe the history of electrochemical scanning tunneling microscopy (STM) and advances made in this field during the past 20 years. In situ STM allows one to monitor various electrode processes, such as the underpotential deposition of copper and silver ions; the specific adsorption of iodine and sulfate/bisulfate ions; electrochemical dissolution processes of silicon and gold single-crystal surfaces in electrolyte solutions; and the molecular assembly of metalloporphyrins, metallophthalocyanines, and fullerenes, at atomic and/or molecular resolution. Furthermore, a laser confocal microscope, combined with a differential interference contrast microscope, enables investigation of the dynamics of electrochemical processes at atomic resolution.

  7. Ligand Induced Anionic Cuprous Cyanide Framework for Cupric Ion Turn on Luminescence Sensing and Photocatalytic Degradation of Organic Dyes.

    PubMed

    Xu, Xiao-Yan; Chen, Qiu-Cheng; Yu, Ya-Dong; Huang, Xiao-Chun

    2016-01-04

    A new microporous luminescent coordination polymer [(CH3)2NH2]·[Cu2(CN)3] (1) with channels occupied by dimethylamine cations was synthesized due to the inducing effect of 2-(2'-pyridyl)imidazole. Complex 1 exhibits bright-green emission in the solid state, and its emission intensity would be significantly enhanced, especially by DMAc and cupric ion after immersing the as-synthesized crystals of 1 into common organic solvents or methanol solutions of various metal ions. In addition, 1 exhibits photocatalytic activity for the degradation of RhB and MB under natural light and is stable during the photocatalysis process. Thus, 1 can act as a multifunctional material for selectively sensing of Cu(2+) and effectively photocatalytic degradation of dyes.

  8. Self-assembly of metal-organic frameworks and graphene oxide as precursors for lithium-ion battery applications

    NASA Astrophysics Data System (ADS)

    Yang, Xia; Liu, Linlin; Yuan, Ruo; Lee, Chun-Sing

    2016-10-01

    We fabricated composites of Fe2O3/reduced graphene oxide as lithium-ion batteries anode material with controlled structures by employing self-assembly of metal-organic frameworks (MOFs) and polymer-functionalized graphene oxide as precursors. By electrostatic interaction, the negatively charged MOFs, Prussian Blue (PB), are assembled on poly(diallyldimethylammonium chloride) (PDDA)-functionalized graphene oxide (positive charge). Then the PB cubes become FeOOH nanosheets when treated with sodium hydroxide. Upon further annealing, the FeOOH nanosheets transform to Fe2O3 nanoparticles while the graphene oxide become reduced graphene oxide simultaneously. It was found that the composites have good performance as anode of lithium-ion battery. This work shows a new way for self-assembling MOFs and 2D materials.

  9. Phase diagram of ammonium nitrate

    NASA Astrophysics Data System (ADS)

    Dunuwille, Mihindra; Yoo, Choong-Shik

    2013-12-01

    Ammonium Nitrate (AN) is a fertilizer, yet becomes an explosive upon a small addition of chemical impurities. The origin of enhanced chemical sensitivity in impure AN (or AN mixtures) is not well understood, posing significant safety issues in using AN even today. To remedy the situation, we have carried out an extensive study to investigate the phase stability of AN and its mixtures with hexane (ANFO-AN mixed with fuel oil) and Aluminum (Ammonal) at high pressures and temperatures, using diamond anvil cells (DAC) and micro-Raman spectroscopy. The results indicate that pure AN decomposes to N2, N2O, and H2O at the onset of the melt, whereas the mixtures, ANFO and Ammonal, decompose at substantially lower temperatures. The present results also confirm the recently proposed phase IV-IV' transition above 17 GPa and provide new constraints for the melting and phase diagram of AN to 40 GPa and 400°C.

  10. Depth resolution at organic interfaces sputtered by argon gas cluster ions: the effect of energy, angle and cluster size.

    PubMed

    Seah, M P; Spencer, S J; Havelund, R; Gilmore, I S; Shard, A G

    2015-10-07

    An analysis is presented of the effect of experimental parameters such as energy, angle and cluster size on the depth resolution in depth profiling organic materials using Ar gas cluster ions. The first results are presented of the incident ion angle dependence of the depth resolution, obtained at the Irganox 1010 to silicon interface, from profiles by X-ray photoelectron spectrometry (XPS). By analysis of all relevant published depth profile data, it is shown that such data, from delta layers in secondary ion mass spectrometry (SIMS), correlate with the XPS data from interfaces if it is assumed that the monolayers of the Irganox 1010 adjacent to the wafer substrate surface have an enhanced sputtering rate. SIMS data confirm this enhancement. These results show that the traditional relation for the depth resolution, FWHM = 2.1Y(1/3) or slightly better, FWHM = P(X)Y(1/3)/n(0.2), where n is the argon gas cluster size, and P(X) is a parameter for each material are valid both at the 45° incidence angle of the argon gas cluster sputtering ions used in most studies and at all angles from 0° to 80°. This implies that, for optimal depth profile resolution, 0° or >75° incidence may be significantly better than the 45° traditionally used, especially for the low energy per atom settings required for the best resolved profiles in organic materials. A detailed analysis, however, shows that the FWHM requires a constant contribution added in quadrature to the above such that there are minimal improvements at 0° or greater than 75°. A critical test at 75° confirms the presence of this constant contribution.

  11. Di-ethyl-ammonium di-hydrogen orthophosphate.

    PubMed

    Held, Peter

    2014-02-01

    In the title molecular salt, [NH2(CH2CH3)2][H2PO4], two unique types of cations and anions, which are configurationally very similar, are present in the asymmetric unit. Both ions form sheets approximately parallel to (-1-1) linked by weak hydrogen bonds. The inter-connection within and between the sheets is reinforced by O-H⋯O and N-H⋯O hydrogen bonds involving the tetra-hedral H2PO4 anions and the ammonium groups.

  12. Holographic materials composed by rosin with ammonium dichromate

    NASA Astrophysics Data System (ADS)

    Ibarra-Torres, Juan Carlos; Olivares-Perez, Arturo; Ortiz-Gutierrez, Mauricio; Perez-Cortes, Mario; Iturbe Castillo, Marcelo D.

    2000-03-01

    We present a new material with potential application in holography. We have used a film of mixing ammonium dichromate with rosin resin diluted in isopropyl alcohol. This material can be easily elaborate in the laboratory. A phase grating in this material was recording using Argon-Ion laser at (lambda) equals 457 nm, showing good diffraction efficiency. This material is capable of high resolution when we record some diffraction gratings, observing 2,000 l/mm (grooves). A characteristic of the developed process is their simplicity, takes approximately 25 seconds.

  13. Rosin (colophony) holograms sensitized with ammonium dichromate ®

    NASA Astrophysics Data System (ADS)

    Olivares-Pérez, A.; Ibarra-Torres, J. C.; Ortiz-Gutiérrez, M.; Pérez-Cortés, M.; Fuentes-Tapia, I.

    2005-12-01

    We report a photosensitive emulsion by mixing ammonium dichromate with rosin resin diluted in isopropyl alcohol. This material can be easily elaborated. A phase grating in this material was recorded using an argon-ion laser at λ = 457 nm, shows a moderate diffraction efficiency. This material is capable of a high resolution when we record some diffraction gratings, observing the order of 2000 l/mm (grooves). A characteristic of the developed process is its simplicity that it takes approximately 25 s. It describes a hypothesis with respect to some mechanisms of photosensitivity in emulsions.

  14. Over-the-top broadcast applications of ammonium nonanoate on onion weed control, crop injury, and yields

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Racer (registered trademark) (40% ammonium nonanoate) is a potential herbicide for organically grown food crops. Ammonium nonanoate occurs in nature and is primarily formed from biodegradation of higher fatty acids. Research was conducted in southeast Oklahoma to determine the effect of applicatio...

  15. 21 CFR 184.1137 - Ammonium carbonate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...). It is prepared by the sublimation of a mixture of ammonium sulfate and calcium carbonate and occurs... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Ammonium carbonate. 184.1137 Section 184.1137 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD...

  16. 21 CFR 184.1137 - Ammonium carbonate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...). It is prepared by the sublimation of a mixture of ammonium sulfate and calcium carbonate and occurs... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Ammonium carbonate. 184.1137 Section 184.1137 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD...

  17. 21 CFR 184.1137 - Ammonium carbonate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... sublimation of a mixture of ammonium sulfate and calcium carbonate and occurs as a white powder or a hard... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Ammonium carbonate. 184.1137 Section 184.1137 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED)...

  18. 21 CFR 184.1137 - Ammonium carbonate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...). It is prepared by the sublimation of a mixture of ammonium sulfate and calcium carbonate and occurs... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Ammonium carbonate. 184.1137 Section 184.1137 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD...

  19. Simple Quaternary Ammonium Ions R4N + ( R= nPr, nBu, nPen) as Versatile Structure Directors for the Synthesis of Zeolite-Like, Heterobimetallic Cyanide Frameworks

    NASA Astrophysics Data System (ADS)

    Poll, Eyck-Michael; Samba, Sabine; Dieter Fischer, R.; Olbrich, Falk; Davies, Nicola A.; Avalle, Paolo; Apperley, David C.; Harris, Robin K.

    2000-06-01

    The preparation of three new examples of water insoluble host/guest assemblies of the general composition: [(R4N)(Me3Sn)2M(CN)6·zH2O] (R=n-propyl or n-pentyl, M=Fe or Co, 0≤z≤2) from likewise polymeric super-Prussian-blue derivatives [(Me3Sn)3M(CN)6] and aqueous (R4N)X solutions are reported. According to combined single-crystal X-ray (3a and 3a*: R=nPr, M=Co, z=2; 5b: R=nPen, M=Fe, z=0.5), powder X-ray diffraction (XRD), and multinuclear (13C, 15N, 59Co, 119Sn) CPMAS solid-state magnetic resonance studies, 3a and 3a* contain cis- and trans-isomeric [Co(CN)4(CNSnMe3OH2)2]- building blocks, respectively, which are held together exclusively by Sn←OH2···NC-Co hydrogen bonds. In striking contrast, the building blocks of 5b and 5a are infinite [M-CN-Sn-NC] chains. In all these assemblies, also significant C-H···NC hydrogen bonds between the encapsulated R4N+ guest ion and exclusively terminal cyanide ligands of the host seem to play a notable auxiliary role.

  20. Ammonium nitrogen in fetuses of urea-treated sheep.

    PubMed

    Yelverton, C C; Roller, M H; Swanson, R N

    1975-02-01

    Eight pregnant Southdown ewes were treated (by drench) with 12.5 ml of 3.3 M urea solution per kilogram of body weight, and ammonium nitrogen concentrations of blood and tissues of these ewes and their fetuses were measured and compared with those of control ewes (given water by drench) and their fetuses. Blood ammonium nitrogen (BAN) and tissue ammonium nitrogen (TAN) concentrations for liver, kidney, spleen, and muscle of ewes and fetuses were determined by an ion-exchange procedure. Samples of blood were collected before treatment, at 30, 90 and 150 minutes after treatment, and at death of the dam. The principal ewes had increasing BAN concentrations with time after drench, and their fetuses had significantly greater (P less than 0.01) BAN concentrations than fetuses from control ewes. All fetuses were alive after death of the dams and had lower TAN values than their dams. The differences in ammonia concentrations between ewes and fetuses were larger in the principal group than in the control group. Except for ewe muscle and fetal liver, all tissues of principals had significantly greater (P less than 0.01) TAN concentrations than those of controls. Muscle of principal ewes and hepatic tissues of their fetuses had greater (P less than 0.05) TAN concentrations than those of control ewes and their fetuses.

  1. SEPARATION OF INORGANIC SALTS FROM ORGANIC SOLUTIONS

    DOEpatents

    Katzin, L.I.; Sullivan, J.C.

    1958-06-24

    A process is described for recovering the nitrates of uranium and plutonium from solution in oxygen-containing organic solvents such as ketones or ethers. The solution of such salts dissolved in an oxygen-containing organic compound is contacted with an ion exchange resin whereby sorption of the entire salt on the resin takes place and then the salt-depleted liquid and the resin are separated from each other. The reaction seems to be based on an anion formation of the entire salt by complexing with the anion of the resin. Strong base or quaternary ammonium type resins can be used successfully in this process.

  2. Lithium Storage Mechanisms in Purpurin Based Organic Lithium Ion Battery Electrodes

    DTIC Science & Technology

    2012-12-11

    Advances in Lithium-ion batteries (Kluwer Academic/Plenum, New York, 2002). 7. Mizushima, K., Jones, P. C., Wiseman, P. J. & Goodenough , J. B. LixCoO2 (0...P. G. & Goodenough , J. B. Electrochemical extraction of lithium from LiMn2O4. Mat. Res. Bull. 18, 461 (1983). 9. Recham, N., Chotard, J. N., Dupont

  3. Self-organized origami structures via ion-induced plastic strain.

    PubMed

    Chalapat, Khattiya; Chekurov, Nikolai; Jiang, Hua; Li, Jian; Parviz, Babak; Paraoanu, G S

    2013-01-04

    Ion processing of the reactive surface of a free-standing polycrystalline metal film induces a flow of atoms into grain boundaries, resulting in plastic deformation. A thorough experimental and theoretical analysis of this process is presented, along with the demonstration of novel engineering concepts for precisely controlled 3D assembly at micro- and nanoscopic scales.

  4. Sputtering Yields for Mixtures of Organic Materials Using Argon Gas Cluster Ions.

    PubMed

    Seah, M P; Havelund, R; Shard, A G; Gilmore, I S

    2015-10-22

    The sputtering yield volumes of binary mixtures of Irganox 1010 with either Irganox 1098 or Fmoc-pentafluoro-L-phenylalanine (FMOC) have been measured for 5 keV Ar2000(+) ions incident at 45° to the surface normal. The sputtering yields are determined from the doses to sputter through various compositions of 100 nm thick, intimately mixed, layers. Because of matrix effects, the profiles for secondary ions are distorted, and profile shifts in depth of 15 nm are observed leading to errors above 20% in the deduced sputtering yield. Secondary ions are selected to avoid this. The sputtering yield volumes for the mixtures are shown to be lower than those deduced from a linear interpolation from the pure materials. This is shown to be consistent with a simple model involving the changing energy absorbed for the sputtering of intimate mixtures. Evidence to support this comes from the secondary ion data for pairs of the different molecules. Both binary mixtures behave similarly, but matrix effects are stronger for the Irganox 1010/FMOC system.

  5. Lanthanide Metal-Organic Frameworks with Six-Coordinated Ln(III) Ions and Free Functional Organic Sites for Adsorptions and Extensive Catalytic Activities

    PubMed Central

    Zhu, Yu; Zhu, Min; Xia, Li; Wu, Yunlong; Hua, Hui; Xie, Jimin

    2016-01-01

    Three chelating-amino-functionalized lanthanide metal-organic frameworks, Y-DDQ, Dy-DDQ and Eu-DDQ, were synthesized with a flexible dicarboxylate ligand based on quinoxaline (H2DDQ = N, N′-dibenzoic acid-2,3-diaminoquinoxaline). The three-dimensional framework is constructed by the H2DDQ linkers connecting the zigzag ladders, showing a net of sra topology. In the structures, one kind of Ln(III) ions metal centers are six-coordinated and thus can potentially behave as open metal sites (OMSs), while the free chelating amino groups can act as free functional organic sites (FOSs). The N2 and Ar adsorption behaviors indicate that these Ln-DDQ exhibits stable microporous frameworks with high surface area after remove of the solvents. Owing to presence of OMSs and FOSs, these MOFs show good ability of CO2, dyes captures and Lewis acid catalyst for cyanosilylation reaction. In view of the existing FOSs in the framework, Pd NPs were immobilized onto the MOFs through graft interactions between free chelating amino groups and metal ions precursor using postsynthetic modification. The well dispersed Pd@Ln-DDQs exhibit efficient and recyclable catalytic reduction of 4-nitrophenol to 4-aminophenol, and they can also act as an excellent catalyst for Suzuki-Miyaura cross-coupling reactions with the exposed Pd NPs. PMID:27431731

  6. Lanthanide Metal-Organic Frameworks with Six-Coordinated Ln(III) Ions and Free Functional Organic Sites for Adsorptions and Extensive Catalytic Activities

    NASA Astrophysics Data System (ADS)

    Zhu, Yu; Zhu, Min; Xia, Li; Wu, Yunlong; Hua, Hui; Xie, Jimin

    2016-07-01

    Three chelating-amino-functionalized lanthanide metal-organic frameworks, Y-DDQ, Dy-DDQ and Eu-DDQ, were synthesized with a flexible dicarboxylate ligand based on quinoxaline (H2DDQ = N, N‧-dibenzoic acid-2,3-diaminoquinoxaline). The three-dimensional framework is constructed by the H2DDQ linkers connecting the zigzag ladders, showing a net of sra topology. In the structures, one kind of Ln(III) ions metal centers are six-coordinated and thus can potentially behave as open metal sites (OMSs), while the free chelating amino groups can act as free functional organic sites (FOSs). The N2 and Ar adsorption behaviors indicate that these Ln-DDQ exhibits stable microporous frameworks with high surface area after remove of the solvents. Owing to presence of OMSs and FOSs, these MOFs show good ability of CO2, dyes captures and Lewis acid catalyst for cyanosilylation reaction. In view of the existing FOSs in the framework, Pd NPs were immobilized onto the MOFs through graft interactions between free chelating amino groups and metal ions precursor using postsynthetic modification. The well dispersed Pd@Ln-DDQs exhibit efficient and recyclable catalytic reduction of 4-nitrophenol to 4-aminophenol, and they can also act as an excellent catalyst for Suzuki-Miyaura cross-coupling reactions with the exposed Pd NPs.

  7. Evolution of Electrogenic Ammonium Transporters (AMTs)

    PubMed Central

    McDonald, Tami R.; Ward, John M.

    2016-01-01

    The ammonium transporter gene family consists of three main clades, AMT, MEP, and Rh. The evolutionary history of the AMT/MEP/Rh gene family is characterized by multiple horizontal gene transfer events, gene family expansion and contraction, and gene loss; thus the gene tree for this family of transporters is unlike the organismal tree. The genomes of angiosperms contain genes for both electrogenic and electroneutral ammonium transporters, but it is not clear how far back in the land plant lineage electrogenic ammonium transporters occur. Here, we place Marchantia polymorpha ammonium transporters in the AMT/MEP/Rh phylogeny and we show that AMTs from the liverwort M. polymorpha are electrogenic. This information suggests that electrogenic ammonium transport evolved at least as early as the divergence of bryophytes in the land plant lineage. PMID:27066024

  8. Synthesis of sodium, potassium cesium, and ammonium O,O-dialkyl phosphoroselenothioates

    SciTech Connect

    Mel'nik, Ya.I.; Prots, D.I.; Kolodii, Ya.I.; Slavich, V.M.

    1986-10-20

    In search for a simpler method for the preparation of the title compounds and in continuation of the investigations on methods of synthesis and properties of organic derivatives of phosphorus seleno acids the authors have investigated the reactions of O,O-dialkyl hydrogen phosphorothioites with selenium and alkali-metal and ammonium carbonates, leading to the corresponding metal (ammonium) O,O-dialkyl phosphoroselenothioates.

  9. Rational design of dynamic ammonium salt catalysts towards more flexible and selective function

    PubMed Central

    Ishihara, Kazuaki

    2009-01-01

    This review focuses on the development of dynamic ammonium salt catalysis for selective organic transformations conducted in our laboratory since 2002. Several important concepts in designing of catalysts are described with some examples. In particular, the practial synthesis of chiral 1,1′-binaphthyl-2,2′-disulfonic acid (BINSA) and its application in chiral ammonium salt catalysis for the enantioselective direct Mannich-type reaction are described. PMID:19838010

  10. 49 CFR 176.415 - Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... nitrates, and certain ammonium nitrate fertilizers. 176.415 Section 176.415 Transportation Other... requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers. (a) Except as... Captain of the Port (COTP). (1) Ammonium nitrate UN1942, ammonium nitrate fertilizers containing more...

  11. 49 CFR 176.415 - Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... nitrates, and certain ammonium nitrate fertilizers. 176.415 Section 176.415 Transportation Other... requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers. (a) Except as... Captain of the Port (COTP). (1) Ammonium nitrate UN1942, ammonium nitrate fertilizers containing more...

  12. 49 CFR 176.415 - Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... nitrates, and certain ammonium nitrate fertilizers. 176.415 Section 176.415 Transportation Other... requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers. (a) Except as... Captain of the Port (COTP). (1) Ammonium nitrate UN1942, ammonium nitrate fertilizers containing more...

  13. 49 CFR 176.415 - Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... nitrates, and certain ammonium nitrate fertilizers. 176.415 Section 176.415 Transportation Other... requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers. (a) Except as... Captain of the Port (COTP). (1) Ammonium nitrate UN1942, ammonium nitrate fertilizers containing more...

  14. 49 CFR 176.415 - Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... nitrates, and certain ammonium nitrate fertilizers. 176.415 Section 176.415 Transportation Other... requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers. (a) Except as... Captain of the Port (COTP). (1) Ammonium nitrate UN1942, ammonium nitrate fertilizers containing more...

  15. Evaluation of ion exchange resins for the removal of dissolved organic matter from biologically treated paper mill effluent.

    PubMed

    Bassandeh, Mojgan; Antony, Alice; Le-Clech, Pierre; Richardson, Desmond; Leslie, Greg

    2013-01-01

    In this study, the efficiency of six ion exchange resins to reduce the dissolved organic matter (DOM) from a biologically treated newsprint mill effluent was evaluated and the dominant removal mechanism of residual organics was established using advanced organic characterisations techniques. Among the resins screened, TAN1 possessed favourable Freundlich parameters, high resin capacity and solute affinity, closely followed by Marathon MSA and Marathon WBA. The removal efficiency of colour and lignin residuals was generally good for the anion exchange resins, greater than 50% and 75% respectively. In terms of the DOM fractions removal measured through liquid chromatography-organic carbon and nitrogen detector (LC-OCND), the resins mainly targeted the removal of humic and fulvic acids of molecular weight ranging between 500 and 1000 g mol(-1), the portion expected to contribute the most to the aromaticity of the effluent. For the anion exchange resins, physical adsorption operated along with ion exchange mechanism assisting to remove neutral and transphilic acid fractions of DOM. The column studies confirmed TAN1 being the best of those screened, exhibited the longest mass transfer zone and maximum treatable volume of effluent. The treatable effluent volume with 50% reduction in dissolved organic carbon (DOC) was 4.8 L for TAN1 followed by Marathon MSA - 3.6L, Marathon 11 - 2.0 L, 21K-XLT - 1.5 L and Marathon WBA - 1.2 L. The cation exchange resin G26 was not effective in DOM removal as the maximum DOC removal obtained was only 27%. The resin capacity could not be completely restored for any of the resins; however, a maximum restoration up to 74% and 93% was achieved for TAN1 and Marathon WBA resins. While this feasibility study indicates the potential option of using ion exchange resins for the reclamation of paper mill effluent, the need for improving the regeneration protocols to restore the resin efficiency is also identified. Similarly, care should be taken

  16. Nanomodified vermiculite NMV - a new material for recycling ammonium nitrogen

    NASA Astrophysics Data System (ADS)

    Rama, Miradije; Laiho, Taina; Eklund, Olav; Lehto, Kirsi; Shebanov, Alex; Smått, Jan-Henrik

    2016-04-01

    Vermiculites ((Mg,Fe,Al)3(Al,Si)4O10(OH)24H2O) are naturally occurring minerals from hydromica group with a high cation exchange capacity and large surface area. Since vermiculite is a hydrated mineral, its structure can be changed with heat. In this study vermiculite samples were heated in an oven until the interlayer distance of them diminished from 14 Å to 11.7 Å. This method for improving vermiculites intake of ammonium ions by heating, is an invention made at the University of Turku. Nanomodified vermiculite (NMV) is able to absorb up to 4.7 wt% of ammonium. NMV can be used as an efficient filter and immobilizer of ammonium in different environments. NMV has been efficiently tested on waste water from a biogas plant, human urine, combustion experiments, industrial chimneys, excrements from farms etc. Ammonium doped vermiculite (ADV) is further developed for fertilizer use. Performed experiments have testified the usability of ADV as a fertilizer. At first step the NMV was processed with the reject water from a biogas plant, were it absorbed NH4+ into the lattice. At second, the ADV was used as nutrient source for garden plants. Geraniums and begonias were used as test plants of the work. Plant growth rate was evaluated based on plant weight. Results showed that significant increase of the growth of geraniums and of begonias were observed when comparing to those cultivations where plants have got normal fertilization. Moreover, ADV has been tested as a fertilizer in greenhouse experiments with spruces and pines. After five months, the weight of the plants that had grown in a substrate containing ADV was 10 times the weight of plants growing in the reference substrate.

  17. Effects of pH adjustment and sodium ions on sour taste intensity of organic acids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Protonated organic acid species have been shown to be the primary stimuli responsible for sour taste of organic acids. However, we have observed that sour taste may be modulated when the pH of acid solutions is raised using sodium hydroxide. Objectives were to evaluate the effect of pH adjustment on...

  18. Proton and metal ion binding to natural organic polyelectrolytes-I. Studies with synthetic model compounds

    USGS Publications Warehouse

    Marinsky, J.A.; Reddy, M.M.

    1984-01-01

    A unified physico-chemical model, based on a modified Henderson-Hasselbalch equation, for the analysis of ion complexation reactions involving charged polymeric systems is presented and verified. In this model pH = pKa+p(??Ka) + log(??/1 - ??) where Ka is the intrinsic acid dissociation constant of the ionizable functional groups on the polymer, ??Ka is the deviation of the intrinsic constant due to electrostatic interaction between the hydrogen ion and the polyanion, and alpha (??) is the polyacid degree of ionization. Using this approach pKa values for repeating acidic units of polyacrylic (PAA) and polymethacrylic (PMA) acids were found to be 4.25 ?? 0.03 and 4.8 ?? 0.1, respectively. The polyion electrostatic deviation term derived from the potentiometric titration data (i.e. p(??Ka)) is used to calculate metal ion concentration at the complexation site on the surface of the polyanion. Intrinsic cobalt-polycarboxylate binding constants (7.5 for PAA and 5.6 for PMA), obtained using this procedure, are consistent with the range of published binding constants for cobalt-monomer carboxylate complexes. In two phase systems incorporation of a Donnan membrane potential term allows determination of the intrinsic pKa of a cross-linked PMA gel, pKa = 4.83, in excellent agreement with the value obtained for the linear polyelectrolyte and the monomer. Similarly, the intrinsic stability constant for cobalt ion binding to a PMA-gel (??CoPMA+ = 11) was found to be in agreement with the linear polyelectrolyte analogue and the published data for cobalt-carboxylate monodentate complexes. ?? 1984.

  19. A Water-Stable Metal-Organic Framework for Highly Sensitive and Selective Sensing of Fe(3+) Ion.

    PubMed

    Hou, Bing-Lei; Tian, Dan; Liu, Jiang; Dong, Long-Zhang; Li, Shun-Li; Li, Dong-Sheng; Lan, Ya-Qian

    2016-10-17

    A new metal-organic framework [Zn5(hfipbb)4(trz)2(H2O)2] (NNU-1) [H2hfipbb = 4,4'-(hexafluoroisopropylidene)bis(benzoic acid), Htrz = 1H-1,2,3-triazole] was assembled by hydrothermal synthesis. Single-crystal X-ray diffraction analysis reveals that NNU-1 displays a twofold interpenetrating three-dimensional (3D) framework with a {4(24)·6(4)}-bcu topology. Interestingly, the 3D framework contains a two-dimensional (2D) layered structure that consists of alternating left- and right-handed double helical chains. On the basis of the hydrophobic -CF3 groups from H2hfipbb ligand, NNU-1 possesses excellent stability in water. It is worth noting that NNU-1 not only shows a highly selective fluorescence quenching effect to Fe(3+) ion in aqueous solution but also resists the interference of other metals including Fe(2+) ion. Accordingly, NNU-1 probably functions as a potential promising fluorescence sensor for detecting Fe(3+) ion with high sensitivity and selectivity.

  20. An environment-friendly and multi-functional absorbent from chitosan for organic pollutants and heavy metal ion.

    PubMed

    Li, Ang; Lin, Runjun; Lin, Chong; He, Bianyang; Zheng, Tingting; Lu, Lingbin; Cao, Yang

    2016-09-05

    Developing environment-friendly green absorbents for disposal of wastewater remains to be studied. In this paper, the cross-linked chitosan aerogel (CsA) as an environment-friendly absorbent was obtained by a simple method involving cross-linked process and freeze drying technique. Compared with conventional absorbents, the porous chitosan aerogel was provided with unique properties such as low density (0.0283g/cm(3)), high porosity (97.98%) and outstanding adsorption performance. The chitosan aerogel also displayed good reusability and excellent elasticity with a maximal thickness recovery up to 96.8% of the original thickness. The as-prepared absorbent exhibited preferable adsorption capacities for crude oil, diesel and copper ion (41.07g/g, 31.07g/g and 21.38mg/g, respectively). The aerogel can collect a wide range of organic solvents and oils with absorption capacities up to 40 times their own weight, depending on the density and viscosity of the liquids. The adsorption capacity for heavy metal ion was also considerable and the maximum adsorption capacity (qm) of the aerogel for copper ion was 35.08mg/g according to Langmuir isotherm model. Consequently, the chitosan aerogel with versatile adsorption properties has a good potential for wastewater treatment in environmental application.