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Sample records for alcoholic carbonate solution

  1. Photoinduced crystallization of calcium carbonate from a homogeneous precursor solution in the presence of partially hydrolyzed poly(vinyl alcohol)

    NASA Astrophysics Data System (ADS)

    Nishio, Takashi; Naka, Kensuke

    2015-04-01

    Photoinduced crystallization of calcium carbonate (CaCO3) was demonstrated by the photodecarboxylation of ketoprofen (KP, 2-(3-benzoylphenyl)propionic acid) under alkaline conditions (pH 10). In this method, a homogeneous solution comprising KP, calcium chloride, ammonia, and partially hydrolyzed poly(vinyl alcohol) (PVAPS, degree of saponification: 86.5-89.0 mol %) was used as the precursor solution and was exposed to ultraviolet (UV) irradiation for different time periods. Thermogravimetric analysis of the obtained xerogels showed that increasing the UV irradiation time increased the amount of CaCO3 formed and the complete conversion of calcium ions to calcite was achieved after 50 min of UV irradiation. Furthermore, solid phase analyses suggested that nanometer-to-micron-sized calcite crystals were formed and dispersed in the obtained PVAPS matrix.

  2. Extracting alcohols from aqueous solutions. [USDOE patent application

    DOEpatents

    Compere, A.L.; Googin, J.M.; Griffith, W.L.

    1981-12-02

    The objective is to provide an efficient process for extracting alcohols in aqueous solutions into hydrocarbon fuel mixtures, such as gasoline, diesel fuel and fuel oil. This is done by contacting an aqueous fermentation liquor with a hydrocarbon or hydrocarbon mixture containing carbon compounds having 5-18 carbon atoms, which may include gasoline, diesel fuel or fuel oil. The hydrocarbon-aqueous alcohol solution is then mixed with one or more of a group of polyoxyalkylene polymers to extract the alcohol into the hydrocarbon fuel-polyoxyalkylene polymer mixture.

  3. Polycondensation kinetics of furfuryl alcohol solutions

    NASA Astrophysics Data System (ADS)

    Zherebtsov, D. A.; Galimov, D. M.; Zagorul'ko, O. V.; Frolova, E. V.; Bol'shakov, O. I.; Zakharov, V. G.; Mikhailov, G. G.

    2016-01-01

    Changes in the viscosity, electrical conductivity, monomer concentration, and the size of growing molecules of polycondensed furfuryl alcohol are studied in solutions containing triethylene glycol and isooctylphenyldecaethylene glycol. The effect the solution compositions have on the condensation kinetics is considered.

  4. Solubilities of stearic acid, stearyl alcohol, and arachidyl alcohol in supercritical carbon dioxide at 35[degree]C

    SciTech Connect

    Iwai, Yoshio; Koga, Yoshio; Maruyama, Hironori; Arai, Yasuhiko . Dept. of Chemical Engineering)

    1993-10-01

    The solubilities of stearic acid (octadecanoic acid), stearyl alcohol (1-octadecanol), and arachidyl alcohol (1-eicosanol) in supercritical carbon dioxide were measured by using a flow-type apparatus at 35 C up to 23.7 MPa. The solubilities of those substances and other fatty acids and higher alcohols in supercritical carbon dioxide at 35 C were correlated by a solution model based on the regular solution model coupled with the Flory-Huggins theory.

  5. Catalytic Hydrogenolysis of 5-Carbon Sugar Alcohols

    SciTech Connect

    Zacher, Alan H.; Frye, John G.; Werpy, Todd A.; Miller, Dennis J.

    2005-01-01

    PNNL, in cooperation with the USDOE and CRADA partners, National Corn Growers Association and Archer Daniels Midland, has developed a new class of catalysts based on Nickel and Rhenium with very effective performance for highly selective, high conversion hydrogenolysis of five–carbon sugar alcohols to useful glycols. The Ni-Re catalyst appears to exhibit preferential hydrogenolysis of the carbon-carbon bonds of secondary carbons over primary carbons of the 5-carbon sugar alcohols tested. In addition, the catalyst has demonstrated significant and unique primary C-O bond hydrogenolysis activity in its ability to convert glycerol into 1,2- propylene glycol, which is then stable in the presence of this class of catalysts. The rhenium containing catalysts are found to have higher activity and better selectivity to desired glycols than previously reported catalysts. A continuous flow reactor lifetime test of over 1500 hours also demonstrated the requisite high stability for an industrially attractive process.

  6. Electrical conductivity of polyvinyl alcohol-multiwall carbon nanotubes composites

    NASA Astrophysics Data System (ADS)

    Amrin, Sayed; Deshpande, V. D.

    2013-06-01

    The dc and ac conductivity of polyvinyl alcohol (PVA)-multiwalled carbon nanotube (MWNT) nanocomposites prepared by solution casting were investigated by employing dielectric relaxation spectroscopy in broad frequency range (0.1 Hz-10 MHz) at room temperature as a function of the conductive weight fraction (p) ranging from 0 to 2wt.%. The frequency dependence of the measured conductivity obeys the universal dynamic response (UDR); a dc plateau followed, by the power law above a critical frequency (fc).

  7. Separation and concentration of lower alcohols from dilute aqueous solutions

    DOEpatents

    Moore, Raymond H.; Eakin, David E.; Baker, Eddie G.; Hallen, Richard T.

    1991-01-01

    A process for producing, from a dilute aqueous solution of a lower (C.sub.1 -C.sub.5) alcohol, a concentrated liquid solution of the alcohol in an aromatic organic solvent is disclosed. Most of the water is removed from the dilute aqueous solution of alcohol by chilling sufficiently to form ice crystals. Simultaneously, the remaining liquid is extracted at substantially the same low temperature with a liquid organic solvent that is substantially immiscible in aqueous liquids and has an affinity for the alcohol at that temperature, causing the alcohol to transfer to the organic phase. After separating the organic liquid from the ice crystals, the organic liquid can be distilled to enrich the concentration of alcohol therein. Ethanol so separated from water and concentrated in an organic solvent such as toluene is useful as an anti-knock additive for gasoline.

  8. Excess enthalpies of solution of primary and secondary alcohols in dodecyldimethylamine oxide micellar solutions

    SciTech Connect

    Milioto, S.; Romancino, D.; De Lisi, R.

    1987-11-01

    The excess enthalpies of solution with respect to water of some primary and secondary alcohols in dodecyldimethylamine oxide (DDAO) micellar solutions were measured by mixing aqueous solutions of alcohols with surfactant solutions. Standard free energies, enthalpies and entropies were obtained from the distribution of alcohol between aqueous and micellar phases. It is shown that thermodynamics of transfer of secondary alcohols from aqueous to the DDAO micellar phase differ slightly from those of their corresponding primary alcohols, that the additivity rule holds for free energies of transfer and that enthalpy and entropy display convex curves. The present data are compared with those from the aqueous to the dodecyltrimethylammonium bromide (DTAB) micellar phases and to the literature data for transfer from water to octane. The role of the hydrophilic interactions between OH group and the micellar head groups and of the hydrophobic interactions between the methylene group and its apolar environment is evidenced.

  9. 27 CFR 19.385 - Making alcohol or water solutions of denaturants.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2012-04-01 2012-04-01 false Making alcohol or water solutions of denaturants. 19.385 Section 19.385 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO... alcohol or water solutions of denaturants. If a proprietor uses a denaturant that is difficult to...

  10. 27 CFR 19.385 - Making alcohol or water solutions of denaturants.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Making alcohol or water solutions of denaturants. 19.385 Section 19.385 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO... alcohol or water solutions of denaturants. If a proprietor uses a denaturant that is difficult to...

  11. Excess enthalpies of solution of some primary and secondary alcohols in sodium dodecylsulfate micellar solutions

    SciTech Connect

    De Lisi, R.; Milioto, S. )

    1988-03-01

    The excess enthalpies of solution of some primary and secondary alcohols in aqueous sodium dodecylsulfate micellar solutions were measured and the results were explained by considering the distribution of alcohols between aqueous and micellar phases. The distribution constant and the enthalpy of transfer (and the standard free energy and entropy of transfer) were obtained. The thermodynamic parameters for the transfer of secondary alcohols from the aqueous to the sodium dodecylsulfate (NaDS) micellar phase differ slightly from those of the corresponding primary alcohols. For both series of alcohols the additivity rule holds for free energies of transfer whereas enthalpies and entropies display convex curves. The present data are compared to those for the transfer of the same solutes from the aqueous to the dodecyldimethylamine oxide (DDAO) and dodecyltrimethylammonium bromide (DTAB) micellar phases.

  12. 27 CFR 19.385 - Making alcohol or water solutions of denaturants.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Making alcohol or water solutions of denaturants. 19.385 Section 19.385 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY ALCOHOL DISTILLED SPIRITS PLANTS...

  13. Aquifer washing by micellar solutions: 2. DNAPL recovery mechanisms for an optimized alcohol surfactant solvent solution

    NASA Astrophysics Data System (ADS)

    Martel, Richard; Lefebvre, René; Gélinas, Pierre J.

    1998-03-01

    A large sand column experiment is used to illustrate the principles of complex organic contaminants (DNAPL) recovery by a chemical solution containing an alcohol ( n-butanol), a surfactant (Hostapur SAS), and two solvents ( d-limonene and toluene). The washing solution is pushed by viscous polymer solutions to keep the displacement stable. The main NAPL recovery mechanisms identified are: (1) immiscible displacement by oil saturation increase (oil swelling), oil viscosity reduction, interfacial tension lowering, and relative permeability increase; (2) miscible NAPL displacement by solubilization. Most of the NAPL was recovered in a Winsor, type II system ahead of the washing solution. The 0.8 pore volume (PV) of alcohol-surfactant-solvent solution injected recovered more than 89% of the initial residual DNAPL saturation (0.195). Winsor system types were determined by visual observation of phases and confirmed by electrical resistivity measurements of phases and water content measurements in the oleic phase. Viscosity and density lowering of the oleic phase was made using solvents and alcohol transfer from the washing solution. Small sand column tests are performed to check different rinsing strategies used to minimize washing solution residual ingredients which can be trapped in sediments. An alcohol/surfactant rinsing solution without solvent, injected behind the washing solution, minimizes solvent trapping in sediments. More than five pore volumes of polymer solution and water must be injected after the rinsing solution to decrease alcohol and SAS concentrations in sediments to an acceptable level. To obtain reasonable trapped surfactant concentrations in sediments, the displacement front between the rinsing solution and the subsequent the following polymer solution has to be stable.

  14. Anodic deprotonation of polyaniline films in alcohol solutions

    SciTech Connect

    Susumu Kuwabata, Nobuo Kihira ); Hiroshi Yoneyama

    1993-05-01

    Polyaniline films prepared by electrochemical oxidation of aniline possess high redox activities both in aqueous acidic and in nonaqueous solutions. The high durability of the film against the redox cycling opens applications of this material to electrochromic and electronic devices and cathode-active materials of rechargeable lithium batteries. Polyaniline films immersed in alcohol solutions such as methanol, ethanol, 1-propanol, and 2-propanol are deprotonated by applying anodic potentials. The potential at which the deprotonation reaction is induced to occur is the most negative at methanol among the above four kinds of alcohols used, and ethanol, 1-propanol, and 2-propanol follow in this order. This finding is quantitatively discussed in terms of the difference of the affinity of the solvent for the protonated polyaniline. An equation to predict the potential at which the conductance of polyaniline is decreased to one-half of the highest conductance by the deprotonation is derived, and the validity of the equation is verified for results obtained both in aqueous solutions of different pH values and in the above alcohol solutions. 26 refs., 9 figs.

  15. Solvation enthalpies of hydrocarbons in water-alcohol solutions

    SciTech Connect

    Antonova, O.A.; Batov, D.V.; Korolev, V.P.

    1994-03-20

    It was found that the enthalpies of solvation of alkanes and xenon in water-alcohol mixtures vary, following a parabolic law relative to the density of the cohesion energy of a mixed solvent ({rho}). The general relationships were obtained for calculation of the solvation enthalpy of alkanes as a function of {rho} of the mixture and of the size of the solute particles. 14 refs., 6 figs.

  16. Oxidative alkoxylation of phosphine in alcohol solutions of copper halides

    NASA Astrophysics Data System (ADS)

    Polimbetova, G. S.; Borangazieva, A. K.; Ibraimova, Zh. U.; Bugubaeva, G. O.; Keynbay, S.

    2016-08-01

    The phosphine oxidation reaction with oxygen in alcohol solutions of copper (I, II) halides is studied. Kinetic parameters, intermediates, and by-products are studied by means of NMR 31Р-, IR-, UV-, and ESR- spectroscopy; and by magnetic susceptibility, redox potentiometry, gas chromatography, and elemental analysis. A reaction mechanism is proposed, and the optimum conditions are found for the reaction of oxidative alkoxylation phosphine.

  17. Oxidative alkoxylation of phosphine in alcohol solutions of copper halides

    NASA Astrophysics Data System (ADS)

    Polimbetova, G. S.; Borangazieva, A. K.; Ibraimova, Zh. U.; Bugubaeva, G. O.; Keynbay, S.

    2016-08-01

    The phosphine oxidation reaction with oxygen in alcohol solutions of copper (I, II) halides is studied. Kinetic parameters, intermediates, and by-products are studied by means of NMR 31P-, IR-, UV-, and ESR- spectroscopy; and by magnetic susceptibility, redox potentiometry, gas chromatography, and elemental analysis. A reaction mechanism is proposed, and the optimum conditions are found for the reaction of oxidative alkoxylation phosphine.

  18. Aquifer washing by micellar solutions: 1. Optimization of alcohol-surfactant-solvent solutions

    NASA Astrophysics Data System (ADS)

    Martel, Richard; Gélinas, Pierre J.; Desnoyers, Jacques E.

    1998-03-01

    Phase diagrams were used for the formulation of alcohol-surfactant-solvent and to identify the DNAPL (Dense Non Aqueous Phase Liquid) extraction zones. Four potential extraction zones of Mercier DNAPL, a mixture of heavy aliphatics, aromatics and chlorinated hydrocarbons, were identified but only one microemulsion zone showed satisfactory DNAPL recovery in sand columns. More than 90 sand column experiments were performed and demonstrate that: (1) neither surfactant in water, alcohol-surfactant solutions, nor pure solvent can effectively recover Mercier DNAPL and that only alcohol-surfactant-solvent solutions are efficient; (2) adding salts to alcohol-surfactant or to alcohol-surfactant-solvent solutions does not have a beneficial effect on DNAPL recovery; (3) washing solution formulations are site specific and must be modified if the surface properties of the solids (mineralogy) change locally, or if the interfacial behavior of liquids (type of oil) changes; (4) high solvent concentrations in washing solutions increase DNAPL extraction but also increase their cost and decrease their density dramatically; (5) maximum DNAPL recovery is observed with alcohol-surfactant-solvent formulations which correspond to the maximum solubilization in Zone C of the phase diagram; (6) replacing part of surfactant SAS by the alcohol n-butanol increases washing solution efficiency and decreases the density and the cost of solutions; (7) replacing part of n-butanol by the nonionic surfactant HOES decreases DNAPL recovery and increases the cost of solutions; (8) toluene is a better solvent than D-limonene because it increases DNAPL recovery and decreases the cost of solutions; (9) optimal alcohol-surfactant-solvent solutions contain a mixture of solvents in a mass ratio of toluene to D-limonene of one or two. Injection of 1.5 pore volumes of the optimal washing solution of n-butanol-SAS-toluene- D-limonene in water can recover up to 95% of Mercier DNAPL in sand columns. In the first

  19. Interaction of Ethyl Alcohol Vapor with Sulfuric Acid Solutions

    NASA Technical Reports Server (NTRS)

    Leu, Ming-Taun

    2006-01-01

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

  20. Evolution of electrical discharge channel in isopropyl alcohol solution

    NASA Astrophysics Data System (ADS)

    Panov, V. A.; Vasilyak, L. M.; Pecherkin, V. Ya; Vetchinin, S. P.; Kulikov, Yu M.; Son, E. E.

    2015-11-01

    Evolution of the spark channel created by the high voltage pulse generator in 15% isopropyl alcohol solution in tap water was investigated experimentally. Fast camera images show the start of spark discharge channel with the anode region glowing, which is due to ionization-overheating instability near the surface of anode electrode. Measured propagation velocity is about 4 m/s and points to thermal process of channel evolution. Partial discharges in gas bubbles near the spark channel were observed. When the channel bridges the gap the cathode flash of lightning occurs which is much brighter than anode glowing and channel one. After destruction of the spark channel the cathode glowing stays for a longer period than anode one.

  1. 27 CFR 19.385 - Making alcohol or water solutions of denaturants.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Making alcohol or water... alcohol or water solutions of denaturants. If a proprietor uses a denaturant that is difficult to dissolve... water prior to its use in the production of denatured spirits. However, the proof of the...

  2. Molecular dynamics study of n-alcohols adsorbed on an aqueous electrolyte solution

    NASA Astrophysics Data System (ADS)

    Daiguji, Hirofumi

    2001-07-01

    The distribution of normal alcohol (n-alcohol) on water and the effect of salt on the structural and dynamical properties of n-alcohol on aqueous electrolyte solutions were investigated using molecular dynamics simulation. The stability of the alcohol distribution was studied for three types of n-alcohol (n-propanol, C3H7OH; n-heptanol, C7H15OH; and n-undecanol, C11H23OH), four or five concentrations of alcohol, and three concentrations of salt. The simulation results reveal the following. The distribution of n-propanol on water is homogeneous at all n-alcohol concentrations studied here and the distribution of n-heptanol and n-undecanol on water is heterogeneous. The n-alcohol concentration at which fluctuations in the alcohol distribution begin to increase depends on the length of the hydrocarbon chain of the n-alcohol. Salt concentration affects the surface excess concentration of n-alcohol and the stability of the adsorbed layer of n-alcohol. The degree of each effect depends on the length of the hydrocarbon chain of the n-alcohol. For n-undecanol, the surface structure of n-alcohol is independent of salt concentration because interaction between the hydrocarbon chains is sufficiently strong. In absorption refrigeration technology, to enhance the absorption rate of water vapor into a highly concentrated aqueous electrolyte solution, a small amount of alcohols is added to the aqueous electrolyte solution, which induces cellular convection referred to as Marangoni instability. Among the three types of n-alcohol studied here, only n-heptanol induces strong cellular convection. The simulations reveal two required conditions for Marangoni instability: generation of fluctuations in the alcohol distribution on water, and strong correlation between the structural and dynamical properties and salt concentration. Among the three types of n-alcohol studied here, based on the simulations, only n-heptanol satisfies both conditions.

  3. CATALYZED OXIDATION OF URANIUM IN CARBONATE SOLUTIONS

    DOEpatents

    Clifford, W.E.

    1962-05-29

    A process is given wherein carbonate solutions are employed to leach uranium from ores and the like containing lower valent uranium species by utilizing catalytic amounts of copper in the presence of ammonia therein and simultaneously supplying an oxidizing agent thereto. The catalysis accelerates rate of dissolution and increases recovery of uranium from the ore. (AEC)

  4. [Photodegradation of paracetamol in carbonate solution].

    PubMed

    Gao, Ying; Yang, Xi; Liu, Yu

    2008-03-01

    The photodegradation of paracetamol in the solution of carbonate with comparably environmental concentration was studied through kinetics method. Experiments were carried out to compare the different photodegradation effects of paracetamol in the solution of carbonate radical and hydroxyl radical. The effects of such factors, pH, nitrate, humic matters, chloride sodium, calcium and magnesium were also analyzed. The products of the photodegradation were identified with GC/MS, and the degradation mechanism of paracetamol was discussed. The results indicate that, the scondary reaction rate constant (k(a)) between paracetamol and carbonate radical is 5.0 x 10(7) L (mol s)(-1), which is lower than that with hydroxyl radical [k(b) = 8.1 x 10(9) L (mol s)(-1)]. But in natural aqueous system, the stable concentration of carbonate radical is much higher than that of hydroxyl. Therefore, the effect of carbonate radical on paracetamol approximately equals to that of hydroxyl radical. The degradation rate of paracetamol increases when the system was changed with higher pH, adding of nitrate, chloride sodium, calcium and magnesium which increase the rigidity of the water, while decreases when the SRFA is present. PMID:18649521

  5. Effects of herbal infusions, tea and carbonated beverages on alcohol dehydrogenase and aldehyde dehydrogenase activity.

    PubMed

    Li, Sha; Gan, Li-Qin; Li, Shu-Ke; Zheng, Jie-Cong; Xu, Dong-Ping; Li, Hua-Bin

    2014-01-01

    Various alcoholic beverages containing different concentrations of ethanol are widely consumed, and excessive alcohol consumption may result in serious health problems. The consumption of alcoholic beverages is often accompanied by non-alcoholic beverages, such as herbal infusions, tea and carbonated beverages to relieve drunk symptoms. The aim of this study was to supply new information on the effects of these beverages on alcohol metabolism for nutritionists and the general public, in order to reduce problems associated with excessive alcohol consumption. The effects of 57 kinds of herbal infusions, tea and carbonated beverages on alcohol dehydrogenase and aldehyde dehydrogenase activity were evaluated. Generally, the effects of these beverages on alcohol dehydrogenase and aldehyde dehydrogenase activity are very different. The results suggested that some beverages should not be drank after excessive alcohol consumption, and several beverages may be potential dietary supplements for the prevention and treatment of problems related to excessive alcohol consumption.

  6. Aqueous solution dispersement of carbon nanotubes

    NASA Technical Reports Server (NTRS)

    Kim, Jae-Woo (Inventor); Park, Cheol (Inventor); Choi, Sang H. (Inventor); Lillehei, Peter T. (Inventor); Harrison, Joycelyn S. (Inventor)

    2011-01-01

    Carbon nanotubes (CNTs) are dispersed in an aqueous buffer solution consisting of at least 50 weight percent water and a remainder weight percent that includes a buffer material. The buffer material has a molecular structure defined by a first end, a second end, and a middle disposed between the first and second ends. The first end is a cyclic ring with nitrogen and oxygen heteroatomes, the middle is a hydrophobic alkyl chain, and the second end is a charged group.

  7. Recovery of anhydrous Na{sub 2}SO{sub 4} from SO{sub 2}-scrubbing liquor by extractive crystallization: Liquid-liquid equilibria for aqueous solutions of sodium carbonate, sulfate, and/or sulfite plus acetone, 2-propanol, or tert-butyl alcohol

    SciTech Connect

    Lynn, S.; Cos, R.; Prausnitz, J.M. |; Schiozer, A.L.; Jaecksch, W.L.

    1996-11-01

    Sodium carbonate is a superior scrubbing agent for removing SO{sub 2} from combustion gases, but the resulting sodium sulfate (or sulfite) must be recovered for environmental reasons. Recovery by evaporative crystallization is energy-intensive; extractive crystallization provides an attractive alterative when technically feasible. Liquid/liquid equilibrium data were determined for two-phase mixtures containing aqueous solutions of sodium carbonate, sulfate, or sulfite and a polar organic solvent: acetone, 2-propanol, and 2-methylpropan-1-ol (i.e., tert-butyl alcohol). In the salt-saturated two-phase region, data were obtained between the lower consolute temperature and 60 C (50 C for acetone). data were also obtained at 35 C for liquid/liquid systems that were subsaturated with their respective salts and for liquid/liquid systems with overall molar ratios of sodium sulfite/sodium sulfate fixed at 25/75, 50/50, and 75/25. In the latter systems, it was found that the sulfite/sulfate ratios in the organic and aqueous phases were the same, i.e., there is no selectivity by these solvents for one salt relative to the other. The data show that any one of these solvents can be used to extract water from a concentrated solution of either sodium sulfite or sodium sulfate in a countercurrent extractor at 35 C, causing the anhydrous salt to crystallize. The wet solvent can be dried for recycle in a similar countercurrent operation at 35 C, using a saturated solution of Na{sub 2}CO{sub 3} as the drying agent. The number of moles of carbonate required for drying does not exceed the number of moles of sulfite-plus-sulfate precipitated. The process energy is about 0% of that required for single-stage evaporative crystallization of the same liquor.

  8. Summary of results of a comparative study of alcohol problems and solutions: Spain and Portugal.

    PubMed

    Nunes-Dinis, M C; Lowe, L

    1992-06-01

    This study explores through a mail questionnaire alcohol problems and solutions in Spain and Portugal including: drunk-driving, treatment services and prevention, economic issues, alcohol consumption, cultural aspects, and supply of alcoholic beverages. Consumption of alcohol in both countries is lower for men and women with college educations. Marital status has minimal effects on the consumption level of men and women in Spain and of men in Portugal. For Portuguese married women, consumption is higher. Too many bars and feasts are primary cultural adjuncts contributing to alcohol problems. PMID:1612818

  9. Olfactory Impact of Higher Alcohols on Red Wine Fruity Ester Aroma Expression in Model Solution.

    PubMed

    Cameleyre, Margaux; Lytra, Georgia; Tempere, Sophie; Barbe, Jean-Christophe

    2015-11-11

    This study focused on the impact of five higher alcohols on the perception of fruity aroma in red wines. Various aromatic reconstitutions were prepared, consisting of 13 ethyl esters and acetates and 5 higher alcohols, all at the average concentrations found in red wine. These aromatic reconstitutions were prepared in several matrices. Sensory analysis revealed the interesting behavior of certain compounds among the five higher alcohols following their individual addition or omission. The "olfactory threshold" of the fruity pool was evaluated in several matrices: dilute alcohol solution, dilute alcohol solution containing 3-methylbutan-1-ol or butan-1-ol individually, and dilute alcohol solution containing the mixture of five higher alcohols, blended together at various concentrations. The presence of 3-methylbutan-1-ol or butan-1-ol alone led to a significant decrease in the "olfactory threshold" of the fruity reconstitution, whereas the mixture of alcohols raised the olfactory threshold. Sensory profiles highlighted changes in the perception of fruity nuances in the presence of the mixture of higher alcohols, with specific perceptive interactions, including a relevant masking effect on fresh- and jammy-fruit notes of the fruity mixture in both dilute alcohol solution and dearomatized red wine matrices. When either 3-methylbutan-1-ol or butan-1-ol was added to the fruity reconstitution in dilute alcohol solution, an enhancement of butyric notes was reported with 3-methylbutan-1-ol and fresh- and jammy-fruit with butan-1-ol. This study, the first to focus on the impact of higher alcohols on fruity aromatic expression, revealed that these compounds participate, both quantitatively and qualitatively, in masking fruity aroma perception in a model fruity wine mixture.

  10. Carbon-coated magnetic palladium: applications in partial oxidation of alcohols and coupling reactions.

    EPA Science Inventory

    Magnetic carbon supported Pd catalyst has been synthesized via in situ generation of nanoferrites and incorporation of carbon from renewable cellulose via calcination; catalyst can be used for oxidation of alcohols, amination reaction and arylation of aryl halides (cross coupli...

  11. Adsorption of Methylene Blue from Aqueous Solutions by Polyvinyl Alcohol/Graphene Oxide Composites.

    PubMed

    Yang, Xiaoxia; Li, Yanhui; Du, Qiuju; Wang, Xiaohui; Hu, Song; Chen, Long; Wang, Zonghua; Xia, Yanzhi; Xia, Linhua

    2016-02-01

    As a new member of the carbon family, graphene oxide (GO) has shown excellent adsorption ability to micro-pollutants in aqueous solutions. However, its tiny size makes it difficult to be removed from aqueous solutions using the conventional separation methods, which limits its practical application in the environmental protection. In this study, polyvinyl alcohol (PVA) was used as carrier immobilizing GO, and novel PVA/GO composites were prepared. The morphology and physicochemical properties of the composites were characterized by SEM, FTIR and TGA analysis. The adsorption properties of methylene blue (MB) onto the composites were studied through investigating the experimental parameters such as solution pH, adsorbent dosage, contact time and temperature. The isotherm data were analyzed using the Langmuir, Freundlich and Dubinin-Radushkevich models. The calculated maximum adsorption capacity reached 476.2 mg/g at 50% GO content. The pseudo-first-order kinetic, pseudo-second-order kinetic and intra-particle diffusion models were used to explore the adsorption kinetics. The results showed that the dynamic data were fitted to the pseudo-second-order kinetic model. PMID:27433669

  12. Alcohol

    MedlinePlus

    ... How Can I Help a Friend Who Cuts? Alcohol KidsHealth > For Teens > Alcohol Print A A A ... you can make an educated choice. What Is Alcohol? Alcohol is created when grains, fruits, or vegetables ...

  13. Aragonite nanorods in calcium carbonate/polymer hybrids formed through self-organization processes from amorphous calcium carbonate solution.

    PubMed

    Kajiyama, Satoshi; Nishimura, Tatsuya; Sakamoto, Takeshi; Kato, Takashi

    2014-04-24

    Nanostructured inorganic/polymer hybrid thin films comprising aragonite nanorods derived from aqueous suspensions of amorphous calcium carbonate (ACC) are prepared. For the formation of calcium carbonate (CaCO₃)/polymer hybrids, spincoated and annealed films of poly(vinyl alcohol) (PVA) that function as polymer matrices are soaked in aqueous colloidal solutions dispersing ACC stabilized by poly(acrylic acid) (PAA). In the initial stage, calcite thin films form on the surface. Subsequently, aragonite crystals start to form inside the PVA matrix that contains PVA crystallites which induce aragonite nucleation. Nanostructured hybrids composed of calcite thin films consisting of nanoparticles and assembled aragonite nanorods are formed in the matrices of PVA.

  14. Mechanical and dielectric properties of carbon nanotubes/poly (vinyl alcohol) nanocomposites

    NASA Astrophysics Data System (ADS)

    Amrin, Sayed; Deshpande, V. D.

    2016-05-01

    In this work, two series of nanocomposites of poly(vinyl alcohol) (PVA) incorporated with multiwalled carbon nanotubes (MWNT) and carboxyl functionalized multiwalled carbon nanotubes (MWNT-COOH) were fabricated using solution-cast method and their tensile and dielectric properties were studied. Tensile tests were carried out on composite films of MWNT/PVA and MWNT-COOH/PVA for different loading levels. Results show that overall mechanical properties of the MWNT-COOH/PVA composite was greatly improved as compared to the MWNT/PVA film. The dielectric properties of nanocomposites were investigated in a frequency range from 0.1Hz to 10MHz at room temperature respectively. Compared to MWNT/PVA composites, higher dielectric constant and ac conductivity was achieved in MWNT-COOH/PVA nanocomposite, which can be well explained by the interfacial polarization effect.

  15. Multicomponent adsorption of alcohols onto silicalite-1 from aqueous solution: isotherms, structural analysis, and assessment of ideal adsorbed solution theory.

    PubMed

    Bai, Peng; Tsapatsis, Michael; Siepmann, J Ilja

    2012-11-01

    Configurational-bias Monte Carlo (CBMC) simulations in the isobaric-isothermal version of the Gibbs ensemble (GE) were carried out to probe the adsorption from aqueous solutions of methanol and/or ethanol onto silicalite-1. This methodology does require neither specification of the chemical potential nor any reference to activity models based on experimental data. The CBMC-GE methodology can be applied to the complete range of mixture compositions from pure water to pure alcohols and can also be used when multiple solute types are present at high concentration. The simulations demonstrate high selectivities for the alcohols (α(ethanol) > α(methanol)) almost over the entire composition range. The ideal adsorbed solution theory is found to substantially underpredict the amount of sorbed water and leads to very large errors for low alcohol solution concentrations. The simulations indicate that, at lower loadings, the adsorbed alcohol molecules can serve as seeds for water adsorption but, at higher loadings, alcohols displace water molecules from their preferred region.

  16. Solubility of the sesquiterpene alcohol patchoulol in supercritical carbon dioxide.

    PubMed

    Hybertson, Brooks M

    2007-01-01

    The solubility of the sesquiterpene alcohol patchoulol in supercritical carbon dioxide was measured at P ranging from 10.0 MPa to 25.0 MPa and T of 40.0 and 50.0 °C using a simple microsampling type apparatus with a 100.5 µL sample loop to remove aliquots for off-line analysis. The system was first validated using vanillin with off-line spectrophotometric analysis, then utilized for patchoulol measurements with off-line GC-MS analysis. The measured solubility of patchoulol in supercritical CO(2) ranged from mole fractions of 0.43 × 10(-3) at 10.0 MPa and 50.0 °C to 9.45 × 10(-3) at 25.0 MPa and 40.0 °C.

  17. Solubility of the sesquiterpene alcohol patchoulol in supercritical carbon dioxide

    PubMed Central

    Hybertson, Brooks M.

    2009-01-01

    The solubility of the sesquiterpene alcohol patchoulol in supercritical carbon dioxide was measured at P ranging from 10.0 MPa to 25.0 MPa and T of 40.0 and 50.0 °C using a simple microsampling type apparatus with a 100.5 µL sample loop to remove aliquots for off-line analysis. The system was first validated using vanillin with off-line spectrophotometric analysis, then utilized for patchoulol measurements with off-line GC-MS analysis. The measured solubility of patchoulol in supercritical CO2 ranged from mole fractions of 0.43 × 10−3 at 10.0 MPa and 50.0 °C to 9.45 × 10−3 at 25.0 MPa and 40.0 °C. PMID:19424449

  18. Alcohol adsorption on softwood lignin from aqueous solutions.

    PubMed

    Yang, Y; Ladisch, M R; Ladisch, C M

    1990-02-01

    Lignin prepared by acid and enzyme hydrolysis of a softwood mixture adsorbs acetone, butanol, and other alcohols while showing only a slight uptake of glucose. Adsorption of butanol is independent of temperature in the range of 30-65 degrees C. The Polanyi theory fits adsorption for the linear alcohols methanol through hexanol with values of DeltaS and Delta(mu) ranging from 2.6 to 26 J mol(-1) K(-1)and -0.8 to -8 kJ/mol. The adsorption capacity is given by Q (g alcohol/g lignin) = KC(*). Where C(*) is the equilibrium alcohol concentration (g/mL), K = epsilon(W)exp (Delta/R), and epsilon(w) is the porosity of the lignin (0.23-0.42 mL/g). The value of the adsorption capacity constant K for n-butanol ranges from 1.3 to 2.7 mL/g on sorbent containing 26-72% lignin, while ethanol is 0.5-0.73, acetone is 0.62-1.0, and glucose is 0.35. Adsorption is shown to occur through combined hydrophobic and hydrophilic interactions of the alkyl and hydroxyl groups, respectively, of the adsorbate with the lignin. Consequently, for the alcohols methanol to hexanol, we present the capacity constant K[=K(R) + K(OH)] as a sum of an alky! adsorption constant (0.1-9.5 mL/g) and a hydrophilic (0.40-0.50 mL/g) contribution. This approach may be applicable to organic acids. Lignin's sorbent properties have potential to moderate product inhibition in the anaerobic acetone-butanol-ethanol (ABE) fermentation. PMID:18592519

  19. Molecular Arrangement and Surface Tension of Alcohol Solutions.

    PubMed

    Phan, Chi M; Nguyen, Cuong V; Pham, Thuy T T

    2016-04-28

    This study investigated the relationship between molecular arrangement and surface tension of water mixtures with methanol and ethanol. It has been found that the molecular structure of interfacial zone was deterministically correlated to alcohol concentration. From the water dipole moment, an interfacial boundary was defined. The boundary then was used to calculate the water and alcohols in the interfacial zone, which was then used to calculate the surface tension. The prediction from simulated data closely followed the experimental data. The analysis revives the relevance of the molecular arrangement, which had been the main focus in the early 20th century, in quantification of surface energy. The results can supplement the current thermodynamic analysis to correctly predict the surface adsorption.

  20. Solubility limits and phase diagrams for fatty alcohols in anionic (SLES) and zwitterionic (CAPB) micellar surfactant solutions.

    PubMed

    Tzocheva, Sylvia S; Danov, Krassimir D; Kralchevsky, Peter A; Georgieva, Gergana S; Post, Albert J; Ananthapadmanabhan, Kavssery P

    2015-07-01

    By analysis of experimental data, a quantitative theoretical interpretation of the solubility limit of medium- and long-chain fatty alcohols in micellar solutions of water-soluble surfactants is presented. A general picture of the phase behavior of the investigated systems is given in the form of phase diagrams. The limited solubility of the fatty alcohols in the micelles of conventional surfactants is explained with the precipitation of their monomers in the bulk, rather than with micelle phase separation. The long chain fatty alcohols (with n=14, 16 and 18 carbon atoms) exhibit an ideal mixing in the micelles of the anionic surfactant sodium laurylethersulfate (SLES) and the zwitterionic surfactant cocamidopropyl betaine (CAPB) at temperatures of 25, 30, 35 and 40 °C. Deviations from ideality are observed for the alcohols of shorter chain (n=10 and 12), which can be explained by a mismatch with the longer chains of the surfactant molecules. Using the determined thermodynamic parameters of the systems, their phase diagrams are constructed. Such a diagram consists of four domains, viz. mixed micelles; coexistent micelles and precipitate (dispersed crystallites or droplets); precipitate without micelles, and molecular solution. The four boundary lines intersect in a quadruple point, Q. For ionic surfactants (like SLES), a detailed theory for calculating the boundary lines of the phase diagrams is developed and verified against data for the positions of the kinks in surface tension isotherms. The theory takes into account the electrostatic interactions in the micellar solutions and the effect of counterion binding. The results can be useful for a quantitative interpretation and prediction of the phase behavior of mixed solutions of two (or more) surfactants, one of them being water soluble and forming micelles, whereas the other one has a limited water solubility, but readily forms mixed micelles with the former surfactant.

  1. Alcohol

    MedlinePlus

    ... Text Size: A A A Listen En Español Alcohol Wondering if alcohol is off limits with diabetes? Most people with diabetes can have a moderate amount of alcohol. Research has shown that there can be some ...

  2. Alcohol

    MedlinePlus

    If you are like many Americans, you drink alcohol at least occasionally. For many people, moderate drinking ... risky. Heavy drinking can lead to alcoholism and alcohol abuse, as well as injuries, liver disease, heart ...

  3. Enthalpic parameters of interaction between diglycylglycine and polyatomic alcohols in aqueous solutions

    NASA Astrophysics Data System (ADS)

    Mezhevoi, I. N.; Badelin, V. G.

    2015-12-01

    Integral enthalpies of solution Δsol H m of diglycylglycine in aqueous solutions of glycerol, ethylene glycol, and 1,2-propylene glycol are measured via solution calorimetry. The experimental data are used to calculate the standard enthalpies of solution (Δsol H°) and transfer (Δtr H°) of the tripeptide from water to aqueous solutions of polyatomic alcohols. The enthalpic pairwise coefficients h xy of interactions between the tripeptide and polyatomic alcohol molecules are calculated using the McMillan-Mayer solution theory and are found to have positive values. The findings are discussed using the theory of estimating various types of interactions in ternary systems and the effect the structural features of interacting biomolecules have on the thermochemical parameters of diglycylglycine dissolution.

  4. Reduction of Plutonium in Acidic Solutions by Mesoporous Carbons

    DOE PAGES

    Parsons-Moss, Tashi; Jones, Stephen; Wang, Jinxiu; Wu, Zhangxiong; Uribe, Eva; Zhao, Dongyuan; Nitsche, Heino

    2015-12-19

    Batch contact experiments with several porous carbon materials showed that carbon solids spontaneously reduce the oxidation state of plutonium in 1-1.5 M acid solutions, without significant adsorption. The final oxidation state and rate of Pu reduction varies with the solution matrix, and also depends on the surface chemistry and surface area of the carbon. It was demonstrated that acidic Pu(VI) solutions can be reduced to Pu(III) by passing through a column of porous carbon particles, offering an easy alternative to electrolysis with a potentiostat.

  5. Polyelectrolyte and carbon nanotube multilayers made from ionic liquid solutions

    NASA Astrophysics Data System (ADS)

    Nakashima, Takuya; Zhu, Jian; Qin, Ming; Ho, Szushen; Kotov, Nicholas A.

    2010-10-01

    The inevitable contact of substrates with water during the traditional practice of layer-by-layer assembly (LBL) creates problems for multiple potential applications of LBL films in electronics. To resolve this issue, we demonstrate here the possibility of a LBL process using ionic liquids (ILs), which potentially eliminates corrosion and hydration processes related to aqueous media and opens additional possibilities in structural control of LBL films. ILs are also considered to be one of the best ``green'' processing solvents, and hence, are advantageous in respect to traditional organic solvents. Poly(ethyleneimine) (PEI) and poly(sodium styrenesulfonate) (PSS) were dispersed in a hydrophilic IL and successfully deposited in the LBL fashion. To produce electroactive thin films with significance to electronics, a similar process was realized for PSS-modified single-walled carbon nanotubes (SWNT-PSS) and poly(vinyl alcohol) (PVA). Characterization of the coating using standard spectroscopy and microscopy techniques typical of the multilayer field indicated that there are both similarities and differences in the structure and properties of LBL films build from ILs and aqueous solutions. The films exhibited electrical conductivity of 102 S m-1 with transparency as high as 98% for visible light, which is comparable to similar parameters for many carbon nanotube and graphene films prepared by both aqueous LBL and other methods.The inevitable contact of substrates with water during the traditional practice of layer-by-layer assembly (LBL) creates problems for multiple potential applications of LBL films in electronics. To resolve this issue, we demonstrate here the possibility of a LBL process using ionic liquids (ILs), which potentially eliminates corrosion and hydration processes related to aqueous media and opens additional possibilities in structural control of LBL films. ILs are also considered to be one of the best ``green'' processing solvents, and hence, are

  6. An e-health solution for people with alcohol problems.

    PubMed

    Gustafson, David H; Boyle, Michael G; Shaw, Bret R; Isham, Andrew; McTavish, Fiona; Richards, Stephanie; Schubert, Christopher; Levy, Michael; Johnson, Kim

    2011-01-01

    Self-management of chronic diseases has been a research focus for years. Information and communication technologies (ICTs) have played a significant role in aiding patients and their families with that management task. The recent dramatic increase in smartphone capabilities has expanded the potential of these technologies by facilitating the integration of features specific to cell phones with advanced capabilities that extend the reach of what type of information can be assessed and which services can be provided. A recent review of the literature covering the use of ICTs in managing chronic diseases, including addiction, has examined the effectiveness of ICTs, with an emphasis on technologies tested in randomized controlled trials. One example of an addiction-relapse prevention system currently being tested is the Alcohol Comprehensive Health Enhancement Support System (A-CHESS) Program. PMID:23293549

  7. Susceptibility of yeast isolates from cattle with otitis to aqueous solution of povidone iodine and to alcohol-ether solution.

    PubMed

    Duarte, E R; Hamdan, J S

    2006-06-01

    Lipid-dependent Malassezia species, Candida spp. and Rhodotorula mucilaginosa have been associated with bovine parasitic otitis. This paper evaluated the susceptibility of 63 yeast isolates from cattle with otitis to a povidone iodine aqueous solution (1% and 0.5% v/v) and to an alcohol-ether solution (1:1 v/v). The effectiveness of these antiseptics was assessed using the European suspension test. Products achieving equal to or greater than 5-log reduction in numbers of the challenge organism after 5 min contact are considered to have as acceptable microbicidal effect (ME). The two antiseptic solutions achieved ME greater than 5, when tested at 1 and 5 min contact time, against the majority of yeast strains. The exceptions were alcohol and ether solution against two Candida tropicalis strains. Urea broth macrodilution method was used to determine the minimum inhibitory concentration (MIC), defined as the lowest concentration that resulted in a visually negative urease test or, in the case of Candida spp., turbidity inhibition when compared with that produced by the growth control. Analysis of the results for all 63 isolates showed Malassezia sympodialis and Rhodotorula mucilaginosa to be more susceptible to povidone iodine and Malassezia furfur strains to be less susceptible. Malassezia sympodialis was significantly more susceptible to alcohol-ether solution than other species. This study showed the in vitro efficacy of alcohol-ether solution and povidone iodine and proposes the need for clinical evaluation of the topical treatment and control of bovine otitis with these antiseptics and their effects on the ear microbiota and the ear canal.

  8. Alcohol

    MedlinePlus

    ... Got Homework? Here's Help White House Lunch Recipes Alcohol KidsHealth > For Kids > Alcohol Print A A A Text Size What's in ... What Is Alcoholism? Say No en español El alcohol Getting the Right Message "Hey, who wants a ...

  9. Metal Nanoparticles Preparation In Supercritical Carbon Dioxide Solutions

    SciTech Connect

    Harry W. Rollins

    2004-04-01

    The novel optical, electronic, and/or magnetic properties of metal and semiconductor nanoparticles have resulted in extensive research on new methods for their preparation. An ideal preparation method would allow the particle size, size distribution, crystallinity, and particle shape to be easily controlled, and would be applicable to a wide variety of material systems. Numerous preparation methods have been reported, each with its inherent advantages and disadvantages; however, an ideal method has yet to emerge. The most widely applied methods for nanoparticle preparation include the sonochemical reduction of organometallic reagents,(1&2) the solvothermal method of Alivisatos,(3) reactions in microemulsions,(4-6) the polyol method (reduction by alcohols),(7-9) and the use of polymer and solgel materials as hosts.(10-13) In addition to these methods, there are a variety of methods that take advantage of the unique properties of a supercritical fluid.(14&15) Through simple variations of temperature and pressure, the properties of a supercritical fluid can be continuously tuned from gas-like to liquid-like without undergoing a phase change. Nanoparticle preparation methods that utilize supercritical fluids are briefly reviewed below using the following categories: Rapid Expansion of Supercritical Solutions (RESS), Reactive Supercritical Fluid Processing, and Supercritical Fluid Microemulsions. Because of its easily accessible critical temperature and pressure and environmentally benign nature, carbon dioxide is the most widely used supercritical solvent. Supercritical CO2 is unfortunately a poor solvent for many polar or ionic species, which has impeded its use in the preparation of metal and semiconductor nanoparticles. We have developed a reactive supercritical fluid processing method using supercritical carbon dioxide for the preparation of metal and metal sulfide particles and used it to prepare narrowly distributed nanoparticles of silver (Ag) and silver sulfide

  10. SN1 reactions in supercritical carbon dioxide in the presence of alcohols: the role of preferential solvation.

    PubMed

    Delgado-Abad, Thais; Martínez-Ferrer, Jaime; Acerete, Rafael; Asensio, Gregorio; Mello, Rossella; González-Núñez, María Elena

    2016-07-01

    Ethanol () inhibits SN1 reactions of alkyl halides in supercritical carbon dioxide (scCO2) and gives no ethers as products. The unexpected behaviour of alcohols in the reaction of alkyl halides with 1,3-dimethoxybenzene () in scCO2 under different conditions is rationalised in terms of Brønsted and Lewis acid-base equilibria of reagents, intermediates, additives and products in a singular solvent characterised by: (i) the strong quadrupole and Lewis acid character of carbon dioxide, which hinders SN2 paths by strongly solvating basic solutes; (ii) the weak Lewis base character of carbon dioxide, which prevents it from behaving as a proton sink; (iii) the compressible nature of scCO2, which enhances the impact of preferential solvation on carbon dioxide availability for the solvent-demanding rate determining step.

  11. Thermal transformation of trans-5-O-caffeoylquinic acid (trans-5-CQA) in alcoholic solutions.

    PubMed

    Dawidowicz, Andrzej L; Typek, Rafal

    2015-01-15

    Chlorogenic acid (CQA), the ester of caffeic acid with quinic acid supplied to human organisms mainly with coffee, tea, fruit and vegetables, has been one of the most studied polyphenols. It is potentially useful in pharmaceuticals, food additives, and cosmetics due to its recently discovered biomedical activity, which revived interest in its properties, isomers and natural occurrence. We found that the heating of the alcoholic solution of trans-5-O-caffeoylquinic acid produced at least twenty compounds (chlorogenic acid derivatives and its reaction products with water and alcohol). The formation of three of them (methoxy, ethoxy and propoxy adducts) has not been reported yet. No reports exist either on methoxy adducts of 3- and 4-O-caffeoylquinic acid appearing in buffered methanol/water mixtures at pH exceeding 7. We observed that the amount of each formed component depended on the heating time, type of alcohol, its concentration in alcoholic/water mixture, and pH.

  12. The antiseptic effect of a quick drying rubbing type povidone-iodine alcoholic disinfectant solution.

    PubMed

    Minakuchi, K; Yamamoto, Y; Matsunaga, K; Hayata, M; Yasuda, T; Katsuno, Y; Takada, H; Iriyama, J; Ishigo, S; Asano, Y

    1993-01-01

    A quick drying rubbing type disinfectant of non-water non-towel type is an antiseptic method suitable for practical use in intensive care units where emergency situations are common. We determined the antiseptic efficacy and safety of a quick drying rubbing type povidone-iodine alcoholic disinfectant solution (HAD Hand Wash) in comparison with benzalkonium chloride alcoholic lotion. The bacterial reduction rate obtained by hand washing with a single 3 ml application was 93.8% for HAD Hand Wash and 94.1% for benzalkonium chloride alcoholic lotion. Thus, excellent antiseptic efficacy was obtained with both disinfectants. Roughening of hand skin which appeared in association with HAD Hand Wash solution was transient and mild in nature in all of the cases, indicating the high safety of this disinfectant. It is justified to say from these findings that HAD Hand Wash is useful as a hand and finger disinfectant.

  13. Application of dual carbon-bromine isotope analysis for investigating abiotic transformations of tribromoneopentyl alcohol (TBNPA).

    PubMed

    Kozell, Anna; Yecheskel, Yinon; Balaban, Noa; Dror, Ishai; Halicz, Ludwik; Ronen, Zeev; Gelman, Faina

    2015-04-01

    Many of polybrominated organic compounds, used as flame retardant additives, belong to the group of persistent organic pollutants. Compound-specific isotope analysis is one of the potential analytical tools for investigating their fate in the environment. However, the isotope effects associated with transformations of brominated organic compounds are still poorly explored. In the present study, we investigated carbon and bromine isotope fractionation during degradation of tribromoneopentyl alcohol (TBNPA), one of the widely used flame retardant additives, in three different chemical processes: transformation in aqueous alkaline solution (pH 8); reductive dehalogenation by zero-valent iron nanoparticles (nZVI) in anoxic conditions; oxidative degradation by H2O2 in the presence of CuO nanoparticles (nCuO). Two-dimensional carbon-bromine isotope plots (δ(13)C/Δ(81)Br) for each reaction gave different process-dependent isotope slopes (Λ(C/Br)): 25.2 ± 2.5 for alkaline hydrolysis (pH 8); 3.8 ± 0.5 for debromination in the presence of nZVI in anoxic conditions; ∞ in the case of catalytic oxidation by H2O2 with nCuO. The obtained isotope effects for both elements were generally in agreement with the values expected for the suggested reaction mechanisms. The results of the present study support further applications of dual carbon-bromine isotope analysis as a tool for identification of reaction pathway during transformations of brominated organic compounds in the environment.

  14. Unified Effect of Hydrophobic Hydration on the Dynamics and the Structure of Water Molecules in Lower Alcohol Aqueous Solutions

    NASA Astrophysics Data System (ADS)

    Nakada, Masaru; Maruyama, Kenji; Yamamuro, Osamu; Kikuchi, Tatsuya; Misawa, Masakatsu

    2011-04-01

    After the analysis of the quasi-elastic neutron scattering (QENS) spectra of lower alcoholic aqueous solutions, we found that the parameter α, which is the number fraction of hydrophobic hydrating water molecules, has an important role in describing the dynamics and other properties of these solutions. The diffusion coefficient D was obtained from QENS spectra using the relaxing cage model, and D was found to have the same linear relation against α for ethyl alcohol, n-propyl alcohol, i-propyl alcohol, and t-butyl alcohol (with a small deviation) aqueous solutions. The excess molar volume and average hydration number of these solutions could also be expressed with common parameters, which are independent of the alcohol species.

  15. Evolution of hydrogen from acidic aqueous and aqueous-alcoholic solutions by reduced forms of isopolytungstates

    SciTech Connect

    Saidkhanov, S.S.; Parmon, V.N.; Savinov, E.N.

    1986-02-10

    The authors determine the specific nature of the hydrogen-releasing polytungstate (PT) species and investigate the features of H/sub 2/ evolution by this species. In aqueous and aqueous-alcohol solutions, reoxidation of the doubly reduced form of hexatungstate proceeds spontaneously, accompanied by hydrogen evolution; in contrast, the reduced form of the PT is stable with respect to reoxidation.

  16. Barrier properties of poly(vinyl alcohol) membranes containing carbon nanotubes or activated carbon.

    PubMed

    Surdo, Erin M; Khan, Iftheker A; Choudhury, Atif A; Saleh, Navid B; Arnold, William A

    2011-04-15

    Carbon nanotube addition has been shown to improve the mechanical properties of some polymers. Because of their unique adsorptive properties, carbon nanotubes may also improve the barrier performance of polymers used in contaminant containment. This study compares the barrier performance of poly(vinyl alcohol) (PVA) membranes containing single-walled carbon nanotubes (SWCNTs) to that for PVA containing powdered activated carbon (PAC). Raw and surface-functionalized versions of each sorbent were tested for their abilities to adsorb 1,2,4-trichlorobenzene and Cu(2+), representing the important hydrophobic organic and heavy metal contaminant classes, as they diffused across the PVA. In both cases, PAC (for 1,2,4-trichlorobenzene) and functionalized PAC (for Cu(2+)) outperformed SWCNTs on a per mass basis by trapping more of the contaminants within the barrier membrane. Kinetics of sorption are important in evaluating barrier properties, and poor performance of SWCNT-containing membranes as 1,2,4-TCB barriers is attributed to kinetic limitations. PMID:21349636

  17. Alcoholism

    PubMed Central

    Girard, Donald E.; Carlton, Bruce E.

    1978-01-01

    There are important measurements of alcoholism that are poorly understood by physicians. Professional attitudes toward alcoholic patients are often counterproductive. Americans spend about $30 billion on alcohol a year and most adults drink alcohol. Even though traditional criteria allow for recognition of the disease, diagnosis is often made late in the natural course, when intervention fails. Alcoholism is a major health problem and accounts for 10 percent of total health care costs. Still, this country's 10 million adult alcoholics come from a pool of heavy drinkers with well defined demographic characteristics. These social, cultural and familial traits, along with subtle signs of addiction, allow for earlier diagnosis. Although these factors alone do not establish a diagnosis of alcoholism, they should alert a physician that significant disease may be imminent. Focus must be directed to these aspects of alcoholism if containment of the problem is expected. PMID:685264

  18. Picosecond Pulse Radiolysis of Highly Concentrated Carbonate Solutions.

    PubMed

    Ghalei, Mohammad; Ma, Jun; Schmidhammer, Uli; Vandenborre, Johan; Fattahi, Massoud; Mostafavi, Mehran

    2016-03-10

    Highly concentrated potassium carbonate aqueous solutions are studied by picosecond pulse radiolysis with the purpose of exploring the formation processes of carbonate radical CO3(•-). The transient absorption band of solvated electron produced by ionizing is markedly shifted from 715 to 600 nm when the solute concentration of K2CO3 is 5 mol L(-1). This spectral shift is even more important than that observed for the solvated electron in 10 mol L(-1) KOH solutions. The broad absorption band of solvated electron in K2CO3 solutions overlaps with that of carbonate radical CO3(•-) formed at ultrashort time. Nitrate ion is used to scavenge the solvated electron and to observe the contribution of carbonate radical CO3(•-). The analysis of the amplitude and the kinetics of carbonate radical formation in highly concentrated solutions shows that CO3(•-) is formed within the electron pulse (7 ps) by two parallel mechanisms: a direct effect on the solute and the oxidation of the solute by water radical hole H2O(•+). These two mechanisms are followed by an additional one, by reaction between the solute and OH(•) radical especially in lower concentration. The radiolytic yield of each process is discussed. PMID:26885876

  19. Dissolution of Spent Nuclear Fuel in Carbonate-Peroxide Solution

    SciTech Connect

    Soderquist, Chuck Z.; Hanson, Brady D.

    2010-01-31

    This study shows that spent UO2 fuel can be completely dissolved in a carbonate-peroxide solution apparently without attacking the metallic Mo-Tc-Ru-Rh-Pd fission product phase. Samples of spent nuclear fuel were pulverized and sieved to a uniform size, then duplicate aliquots were weighed into beakers for analysis. One set was dissolved in near-boiling 10M nitric acid, and the other set was dissolved in a solution of ammonium carbonate and hydrogen peroxide at room temperature. All the resulting fuel solutions were then analyzed for Sr-90, Tc-99, Cs-137, plutonium, and Am-241. For all the samples, the concentrations of Cs-137, Sr-90, plutonium, and Am-241 were the same for both the nitric acid dissolution and the ammonium carbonate-hydrogen peroxide dissolution, but the technetium concentration of the ammonium carbonate-hydrogen peroxide fuel solution was only about 25% of the same fuels dissolved in hot nitric acid.

  20. Redox reactions of actinides in carbonate and alkaline solutions

    NASA Astrophysics Data System (ADS)

    Shilov, Vladimir P.; Yusov, Aleksander B.

    2002-06-01

    Data on redox reactions involving uranium, neptunium, plutonium and americium ions in carbonate and alkaline solutions are generalised. The results of kinetic studies of these reactions are analysed and their mechanisms are discussed. The bibliography includes 169 references.

  1. Influence of biuret and cyanuric acid on dewaxing petroleum stocks with alcoholic urea solution

    SciTech Connect

    Abdullaev, E.Sh.; Ismailov, A.G.; Gadzhiev, A.Sh.; Balayan, R.D.

    1987-11-01

    The influence of biuret and cyanuric acid contents on the formation and separation of the adduct in commercial dewaxing of petroleum stocks by a urea solution in a water and isopropyl alcohol mixture was studied. The stock was a diesel fuel distillate with a solid point of -12/sup 0/C. Experiments were performed with a 3.5:1 volume ratio of urea solution to feed, urea content 38% by weight, isopropyl alcohol concentration 70% by weight, adduct formation temperature 55-30/sup 0/C, and adduct formation duration 30 min. Test results show the adverse effects at different quantities of cyanuric and biuret acids on adduct formation. Solutions for overcoming these effects are proposed.

  2. Butyric acid esterification kinetics over Amberlyst solid acid catalysts: the effect of alcohol carbon chain length.

    PubMed

    Pappu, Venkata K S; Kanyi, Victor; Santhanakrishnan, Arati; Lira, Carl T; Miller, Dennis J

    2013-02-01

    The liquid phase esterification of butyric acid with a series of linear and branched alcohols is examined. Four strong cation exchange resins, Amberlyst™ 15, Amberlyst™ 36, Amberlyst™ BD 20, and Amberlyst™ 70, were used along with para-toluenesulfonic acid as a homogeneous catalyst. The effect of increasing alcohol carbon chain length and branching on esterification rate at 60°C is presented. For all catalysts, the decrease in turnover frequency (TOF) with increasing carbon chain length of the alcohol is described in terms of steric hindrance, alcohol polarity, and hydroxyl group concentration. The kinetics of butyric acid esterification with 2-ethylhexanol using Amberlyst™ 70 catalyst is described with an activity-based, pseudo-homogeneous kinetic model that includes autocatalysis by butyric acid.

  3. Effect of sonication on the mechanical properties of poly (vinyl alcohol)/carbon nanotube composites

    NASA Astrophysics Data System (ADS)

    Truong, Van-Tan; Tsang, Kelly M. C.; Keough, Shannon J.; St John, Nigel A.

    2006-12-01

    Several sonication procedures were performed on multi-walled carbon nanotubes (MWNTs) in water by varying the length of time, the output power and the type of sonicating horn. Depending on the sonicating conditions, the multi-walled carbon nanotubes (MWNTs) could be well or poorly exfoliated and dispersed. Poly (vinyl alcohol) (PVA) and MNWT (0.5 wt%) composites were cast from the PVA/MWNT aqueous mixture. Enhancement of the mechanical properties of the composites was related to two factors: (1) crystallinity formed at the PVA and MWNT interface and (2) the size of nanotube agglomerates. The poorly dispersed solution produced nanotube agglomerates with the size of 50-100 μm that did not induce crystallization at the polymer/nanotube interface. They became stress concentrators reducing the Young's modulus and the tensile strength. Optimized sonication procedures resulted in well-dispersed nanotube agglomerates of submicron dimensions efficiently enhancing the mechanical properties. As centrifugation facilitated the removal of large agglomerates, noticeable enhancement of mechanical properties of the composites was achieved.

  4. Higher alcohols from synthesis gas using carbon-supported doped molybdenum-based catalysts

    SciTech Connect

    Li, X.; Feng, L.; Liu, Z.; Zhong, B.; Dadyburjor, D.B.; Kugler, E.L.

    1998-10-01

    A series of carbon-supported molybdenum-based catalysts was prepared by incipient wetness impregnation. The materials, when promoted with potassium and additionally with cobalt, were screened for the selective production of mixed higher-molecular weight alcohols from syngas. The effects of the catalyst preparation parameters (Mo precursor, Mo loading, doping levels of K and Co, and calcination) and of the reaction conditions (temperature and space velocity) were studied. The screening procedure consisted of ramping the temperature steadily from 200 to 400 C and back again. Adding K results in a maximum in the space-time yield (STY) of total alcohols and the ratio of higher alcohols to methanol. Increasing the reaction temperature results in a monotonic increase in the STY of hydrocarbons, a monotonic decrease in the selectivity toward alcohols, and a maximum in the STY of alcohols. Increasing the space velocity increases the STY and selectivity to alcohols while decreasing the STY of hydrocarbons. Increasing the space velocity also decreases the higher-alcohol fraction in the alcohol products.

  5. Catalytic conversion of alcohols having at least three carbon atoms to hydrocarbon blendstock

    DOEpatents

    Narula, Chaitanya K.; Davison, Brian H.

    2015-11-13

    A method for producing a hydrocarbon blendstock, the method comprising contacting at least one saturated acyclic alcohol having at least three and up to ten carbon atoms with a metal-loaded zeolite catalyst at a temperature of at least 100°C and up to 550°C, wherein the metal is a positively-charged metal ion, and the metal-loaded zeolite catalyst is catalytically active for converting the alcohol to the hydrocarbon blendstock, wherein the method directly produces a hydrocarbon blendstock having less than 1 vol % ethylene and at least 35 vol % of hydrocarbon compounds containing at least eight carbon atoms.

  6. Methods for sequestering carbon dioxide into alcohols via gasification fermentation

    DOEpatents

    Gaddy, James L; Ko, Ching-Whan; Phillips, J. Randy; Slape, M. Sean

    2013-11-26

    The present invention is directed to improvements in gasification for use with synthesis gas fermentation. Further, the present invention is directed to improvements in gasification for the production of alcohols from a gaseous substrate containing at least one reducing gas containing at least one microorganism.

  7. Using micromechanical resonators to measure rheological properties and alcohol content of model solutions and commercial beverages.

    PubMed

    Paxman, Rosemary; Stinson, Jake; Dejardin, Anna; McKendry, Rachel A; Hoogenboom, Bart W

    2012-01-01

    Micromechanic resonators provide a small-volume and potentially high-throughput method to determine rheological properties of fluids. Here we explore the accuracy in measuring mass density and viscosity of ethanol-water and glycerol-water model solutions, using a simple and easily implemented model to deduce the hydrodynamic effects on resonating cantilevers of various length-to-width aspect ratios. We next show that these measurements can be extended to determine the alcohol percentage of both model solutions and commercial beverages such as beer, wine and liquor. This demonstrates how micromechanical resonators can be used for quality control of every-day drinks.

  8. Novel Microwave Thermodynamic Model for Alcohol with Clustering Structure in Nonpolar Solution.

    PubMed

    Sumi, Takuya; Dillert, Ralf; Horikoshi, Satoshi

    2015-11-12

    A solution containing ethanol as polar material and either benzene or n-dodecane as nonpolar solvent was heated by microwave irradiation employing a single-mode resonance microwave device. Although the microwave heating efficiency was expected from the just value of the relative dielectric constant (εr') or relative dielectric loss (εr″) for liquid system, it was revealed that the clustering structure of alcohol molecules expected from the excess parameter such as the excess relative dielectric loss is the important factor in the decision for efficiency of the microwave heating for the solution. This assumption and novel theory were strongly supported from the thermodynamic data such as vapor pressure and the partial enthalpy.

  9. Using Micromechanical Resonators to Measure Rheological Properties and Alcohol Content of Model Solutions and Commercial Beverages

    PubMed Central

    Paxman, Rosemary; Stinson, Jake; Dejardin, Anna; McKendry, Rachel A.; Hoogenboom, Bart W.

    2012-01-01

    Micromechanic resonators provide a small-volume and potentially high-throughput method to determine rheological properties of fluids. Here we explore the accuracy in measuring mass density and viscosity of ethanol-water and glycerol-water model solutions, using a simple and easily implemented model to deduce the hydrodynamic effects on resonating cantilevers of various length-to-width aspect ratios. We next show that these measurements can be extended to determine the alcohol percentage of both model solutions and commercial beverages such as beer, wine and liquor. This demonstrates how micromechanical resonators can be used for quality control of every-day drinks. PMID:22778654

  10. Solution behavior of metoclopramide in aqueous-alcoholic solutions at 30°C

    NASA Astrophysics Data System (ADS)

    Deosarkar, S. D.; Sawale, R. T.; Tawde, P. D.; Kalyankar, T. M.

    2016-07-01

    Densities (ρ) and refractive indices ( n D) of solutions of antiemetic drug metoclopramide (4-amino-5-chloro- N-(2-(diethylamino)ethyl)-2-methoxybenzamide hydrochloride hydrate) in methanolwater and ethanol-water mixtures of different compositions were measured at 30°C. Apparent molar volume (φv) of the drug was calculated from density data and partial molar volumes (φ v 0 ) were determined from Massons relation. Concentration dependence of nD has been studied to determine refractive indices of solution at infinite dilution ( n D 0 ). Results have been interpreted in terms of solute-solvent interactions.

  11. Phase transition of carbonate solvent mixture solutions at low temperatures

    NASA Astrophysics Data System (ADS)

    Okumura, Takefumi; Horiba, Tatsuo

    2016-01-01

    The phase transition of carbonate solvent mixture solutions consisting of ethylene carbonate (EC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), and LiPF6 salt have been studied for improving the low temperature performance of lithium-ion batteries. The Li ion conductivity at 25 °C was maximum at x = 0.3 in a series of 1 M LiPF6 mixed carbonate solvents compositions consisting of ECxDMC0.5-0.5xEMC0.5-0.5x (x = 0 to 0.6), while the maximum tended to shift to x = 0.2 as the temperature lowered. The differential scanning calorimetry results showed that the freezing temperature depressions of EC in the 1 M LiPF6 solution were larger than those of the DMC or EMC. The chemical shift of 7Li nuclear magnetic resonance changed from a constant to increasing at around x = 0.3, which could be reasonably understood by focusing on the change in solvation energy calculated using Born equation. However, in the region of a high EC concentration of over x = 0.3 (EC/LiPF6 > 4) in the 1 M LiPF6 solution, the free EC from the solvation to the lithium ions seems to reduce the freezing temperature depression of the EC, and thus, decreases the ionic conductivity of the solution at low temperatures, due to the EC freezing.

  12. Modeling Corrosion Reactions of Steel in a Dilute Carbonate Solution

    NASA Astrophysics Data System (ADS)

    Eliyan, Faysal Fayez; Alfantazi, Akram

    2016-02-01

    This research models the corrosion reactions of a high-strength steel in an aerated, dilute, carbonate solution during a single-cycle voltammetry. Based on a previous study (Eliyan et al. in J Mater Eng Perform 24(6):1-8, 2015) and a literature survey, the corrosion reactions of the cathodic reduction, anodic dissolution, and passivation, as well as the interfacial interactions and the chemistry of the corrosion products are illustrated in schematics. The paper provides a visual guide on the corrosion reactions for steel in carbonate solutions based on the available mechanistic details that were reported and are still being investigated in literature.

  13. Catalytic activity of carbon nanotubes in the conversion of aliphatic alcohols

    NASA Astrophysics Data System (ADS)

    Zhitnev, Yu. N.; Tveritinova, E. A.; Chernyak, S. A.; Savilov, S. V.; Lunin, V. V.

    2016-06-01

    Carbon nanotubes (CNTs) obtained via the catalytic pyrolysis of hexane at 750°C were studied as the catalysts in conversion of C2-C4 alcohols. The efficiency of CNTs as catalysts in dehydration and dehydrogenation of ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, and tert-butanol was studied by means of pulse microcatalysis. The surface and structural characteristics of CNTs are investigated via SEM, TEM, DTA, BET, and XPS. CNTs are shown to be effective catalysts in the conversion of alcohols and do not require additional oxidative treatment. The regularities of the conversion of aliphatic alcohols, related to the properties of the CNTs surface and the structure of the alcohols are identified.

  14. Alcohol.

    ERIC Educational Resources Information Center

    Schibeci, Renato

    1996-01-01

    Describes the manufacturing of ethanol, the effects of ethanol on the body, the composition of alcoholic drinks, and some properties of ethanol. Presents some classroom experiments using ethanol. (JRH)

  15. Multivariate Curve Resolution Methods Illustrated Using Infrared Spectra of an Alcohol Dissolved in Carbon Tetrachloride

    ERIC Educational Resources Information Center

    Grung, Bjorn; Nodland, Egil; Forland, Geir Martin

    2007-01-01

    The analysis of the infrared spectra of an alcohol dissolved in carbon tetrachloride gives a better understanding of the various multivariate curve resolution methods. The resulting concentration profile is found to be very useful for calculating the degree of association and equilibrium constants of different compounds.

  16. Viscosities of cetylpyridinium bromide solutions (aqueous and aqueous KBr) in the presence of alcohols and amines

    SciTech Connect

    David, S.L.; Kumar, S.; Kabir-ud-Din

    1997-01-01

    Among the large number of additives, alcohols hold a special place, being by far the most common cosurfactants which are added to surfactant-oil combinations to generate microemulsions. Though the studies using amines as cosurfactant in microemulsions are few, it has been proved that they are also potential candidates for such formulations. The effect of organic additives (aliphatic/aromatic amines or alcohols) on the viscosities of aqueous and 0.1 M KBr solutions of 0.05 or 0.1 M cetylpyridinium bromide have been measured under Newtonian flow conditions. The viscosity changed dramatically in the presence of KBr. This is explained by the favorable conditions produced by the salt which assists the micellar growth by organic additives with a concomitant enhancement in viscosity. Reasons for the effectiveness of these additives are suggested. The causes of the viscosity decrease at higher concentrations of the additive are also explained.

  17. Thermodynamics of micelle formation in a water-alcohol solution of sodium tetradecyl sulfate

    NASA Astrophysics Data System (ADS)

    Shilova, S. V.; Tret'yakova, A. Ya.; Barabanov, V. P.

    2016-01-01

    The effects of addition of ethanol and propan-1-ol on sodium tetradecyl sulfate micelle formation in an aqueous solution are studied via microprobe fluorescence microscopy and conductometry. The critical micelle concentration, quantitative characteristics of micelles, and thermodynamic parameters of micelle formation are determined. Addition of 5-15 vol % of ethanol or 5-10 vol % of propan-1-ol is shown to result in a lower critical micelle concentration than in the aqueous solution, and in the formation of mixed spherical micelles whose sizes and aggregation numbers are less than those for the systems without alcohol. The contribution from the enthalpy factor to the free energy of sodium tetradecyl sulfate micelle formation is found to dominate in mixed solvents, in contrast to aqueous solutions.

  18. Carbon-coated hexagonal magnetite nanoflakes production by spray CVD of alcohols in mixture with water

    NASA Astrophysics Data System (ADS)

    Reyes-Reyes, Marisol; Hernández-Arriaga, Daniel; López-Sandoval, Román

    2014-12-01

    In this study, we report a successful technique for synthesizing magnetite hexagonal nanoflakes coated with carbon layers using spray thermal decomposition, which is a reproducible method that is easy to scale up. We investigated the effects of mixing different volumes of deionized (DI) water with alcohol on the population and quality of single-crystalline Fe3O4 hexagonal nanoflakes. Methanol and ethanol were used as the carbon and oxygen source, while ferrocene was mainly used as the Fe source. To obtain a large quantity of hexagonal structures, a strongly oxidative atmosphere was required. The DI water was used to enhance the oxidative environment during the reaction and was an important component for obtaining well-shaped hexagonal magnetite crystalline nanoflakes. The use of alcohols, water and the spray chemical vapor deposition (CVD) method make this procedure easy to use. In addition, this method provides a one-step process for synthesizing carbon-coated hexagonal Fe3O4 nanocrystals.

  19. Carbon-Nanotubes-Supported Pd Nanoparticles for Alcohol Oxidations in Fuel Cells: Effect of Number of Nanotube Walls on Activity.

    PubMed

    Zhang, Jin; Lu, Shanfu; Xiang, Yan; Shen, Pei Kang; Liu, Jian; Jiang, San Ping

    2015-09-01

    Carbon nanotubes (CNTs) are well known electrocatalyst supports due to their high electrical conductivity, structural stability, and high surface area. Here, we demonstrate that the number of inner tubes or walls of CNTs also have a significant promotion effect on the activity of supported Pd nanoparticles (NPs) for alcohol oxidation reactions of direct alcohol fuel cells (DAFCs). Pd NPs with similar particle size (2.1-2.8 nm) were uniformly assembled on CNTs with different number of walls. The results indicate that Pd NPs supported on triple-walled CNTs (TWNTs) have the highest mass activity and stability for methanol, ethanol, and ethylene glycol oxidation reactions, as compared to Pd NPs supported on single-walled and multi-walled CNTs. Such a specific promotion effect of TWNTs on the electrocatalytic activity of Pd NPs is not related to the contribution of metal impurities in CNTs, oxygen-functional groups of CNTs or surface area of CNTs and Pd NPs. A facile charge transfer mechanism via electron tunneling between the outer wall and inner tubes of CNTs under electrochemical driving force is proposed for the significant promotion effect of TWNTs for the alcohol oxidation reactions in alkaline solutions.

  20. Solvothermal synthesis of superhydrophobic hollow carbon nanoparticles from a fluorinated alcohol

    NASA Astrophysics Data System (ADS)

    Lyth, S. M.; Ma, W.; Liu, J.; Daio, T.; Sasaki, K.; Takahara, A.; Ameduri, B.

    2015-09-01

    A new and simple method of synthesizing fluorinated carbon at the gram scale is presented by reacting a fluorinated alcohol with sodium at elevated temperatures in a sealed Teflon reactor. The resulting carbon nanoparticles are around 100 nm in diameter, and display a hollow shell morphology, with a significant amount of fluorine doped into the carbon. The nanoparticles disperse easily in ethanol, and are thermally stable up to 400 °C and 450 °C under air and nitrogen, respectively. The nanoparticle dispersion was printed onto various substrates (paper, cloth, silicon), inducing superhydrophobicity.

  1. Perfluorinated alcohols and acids induce coacervation in aqueous solutions of amphiphiles.

    PubMed

    Khaledi, Morteza G; Jenkins, Samuel I; Liang, Shuang

    2013-02-26

    We have discovered that water-miscible perfluorinated alcohols and acids (FA) can induce simple and complex coacervation in aqueous solutions of a wide range of amphiphilic molecules such as synthetic surfactants, phospholipids, and bile salts as well as polyelectrolytes. This unique phenomenon seems to be nearly ubiquitous, especially for complex coacervate systems composed of mixed catanionic amphiphiles. In addition, coacervation and aqueous phase separation were observed over a wide range of surfactants concentrations and for different mole fractions of the oppositely charged amphiphile.

  2. ELISA assays and alcohol: increasing carbon chain length can interfere with detection of cytokines.

    PubMed

    von Maltzan, Kristine; Pruett, Stephen B

    2011-02-01

    Enzyme-linked immunosorbent assays (ELISAs) are frequently used in studies on cytokine production in response to treatment of cell cultures or laboratory animals. When an ELISA assay is performed on cell culture supernatants, samples often contain the treatment agents. The purpose of the present study was to determine if some of the agents evaluated might inhibit cytokine detection by interfering with the ELISA, leaving the question of whether cytokine production was inhibited unanswered. Mouse and human cytokine ELISA kits from BD Biosciences were used according to the manufacturer's instructions. Cytokine proteins were subjected to one to five carbon alcohols at 86.8mM (methanol, ethanol, 1-propanol, 2-propanol, n-butanol, and n-pentanol). After treating cell cultures with alcohols of different carbon chain lengths, we found that some of the alcohols interfered with measurement of some cytokines by ELISA, thus making their effects on cytokine production by cells in culture unclear. Increasing carbon chain length of straight chain alcohols positively correlated with their ability to inhibit detection of tumor necrosis factor alpha (TNF-α) and interleukin 10 (IL-10), but not with the detection of interleukin 6 (IL-6), interleukin 8, (IL-8), and interleukin 12 (IL-12). To avoid misinterpretation of treatment effects, ELISA assays should be tested with the reference protein and the treatment agent first, before testing biological samples. These results along with other recent results we obtained using circular dichroism indicate that alcohols with two or more carbons can directly alter protein conformation enough to disrupt binding in an ELISA (shown in the present study) or to inhibit ligand-induced conformational changes (results not shown). Such direct effects have not been given enough consideration as a mechanism of ethanol action in the immune system.

  3. Inhibition of nucleation and growth of ice by poly(vinyl alcohol) in vitrification solution.

    PubMed

    Wang, Hai-Yan; Inada, Takaaki; Funakoshi, Kunio; Lu, Shu-Shen

    2009-08-01

    Control of ice formation is crucial in cryopreservation of biological substances. Successful vitrification using several additives that inhibit ice nucleation in vitrification solutions has previously been reported. Among these additives, here we focused on a synthetic polymer, poly(vinyl alcohol) (PVA), and investigated the effects of PVA on nucleation and growth of ice in 35% (w/w) aqueous 1,2-propanediol solution by using a differential scanning calorimetry (DSC) system equipped with a cryomicroscope. First, the freezing temperature of the solution was measured using the DSC system, and then the change in ice fraction in the solution during cooling was evaluated based on images obtained using the cryomicroscope, at different concentrations of PVA between 0% and 3% (w/w). Based on the ice fraction, the change in residual solution concentration during cooling was also evaluated and then plotted on the state diagram of aqueous 1,2-propanediol solution. Results indicated that, when the partially glassy and partially frozen state was intentionally allowed, the addition of PVA effectively inhibited not only ice nucleation but also ice growth in the vitrification solution. The effect of PVA on ice growth in the vitrification solution was explained based on kinetic limitations mainly due to mass transport. The interfacial kinetics also might limit ice growth in the vitrification solution only when the ice growth rate decreased below a critical value. This coincides with the fact that PVA exhibits a unique antifreeze activity in the same manner as antifreeze proteins when ice growth rate is lower than a critical value.

  4. The surface chemistry of lithium electrodes in alkyl carbonate solutions

    SciTech Connect

    Aurbach, D.; Ein-Ely, Y.; Zaban, A.

    1994-01-01

    The chemical composition of the surface films formed on lithium in alkyl carbonate solutions was explored using surface sensitive Fourier transform infrared spectroscopy (external reflectance mode). The solvents included propylene carbonate, ethylene carbonate, and dimethyl carbonate. The salts included LiAsF{sub 6}, LiClO{sub 4}, LiBF{sub 4}, and LiPF{sub 6}. The advantages of this work over previous studies are that highly reflective Li surfaces were prepared fresh in solution and that the aging processes of the surface films initially formed could be rigorously investigated. Furthermore these three important solvents were investigated in a single study. This work further proves that the films initially formed on Li surfaces in these solvents consist of ROCO{sub 2}Li as the major constituents. Upon storage, the films initially formed react with trace water to form Li{sub 2}CO{sub 3}, which gradually also becomes a major surface species. It was found that these aging processes also depend on the salts used (for example ROCO{sub 2}Li or Li{sub 2}CO{sub 3} films are not stable in LiPF{sub 6} or LiBF{sub 4} solutions).

  5. Simultaneous leaching and carbon sequestration in constrained aqueous solutions.

    PubMed

    Moon, Ji-Won; Cho, Kyu-Seong; Moberly, James G; Roh, Yul; Phelps, Tommy J

    2011-12-01

    The behavior of metal ions' leaching and precipitated mineral phases of metal-rich fly ash (FA) was examined in order to evaluate microbial impacts on carbon sequestration and metal immobilization. The leaching solutions consisted of aerobic deionized water (DW) and artificial eutrophic water (AEW) that was anaerobic, organic- and mineral-rich, and higher salinity as is typical of bottom water in eutrophic algae ponds. The Fe- and Ca-rich FAs were predominantly composed of quartz, mullite, portlandite, calcite, hannebachite, maghemite, and hematite. After 86 days, only Fe and Ca contents exhibited a decrease in leaching solutions while other major and trace elements showed increasing or steady trends in preference to the type of FA and leaching solution. Ca-rich FA showed strong carbon sequestration efficiency ranging up to 32.3 g CO(2)/kg FA after 86 days, corresponding to almost 65% of biotic carbon sequestration potential under some conditions. Variations in the properties of FAs such as chemical compositions, mineral constituents as well as the type of leaching solution impacted CO(2) capture. Even though the relative amount of calcite increased sixfold in the AEW and the relative amount of mineral phase reached 37.3 wt% using Ca-rich FA for 86 days, chemical sequestration did not accomplish simultaneous precipitation and sequestration of several heavy metals.

  6. Simultaneous leaching and carbon sequestration in constrained aqueous solutions

    SciTech Connect

    Phelps, Tommy Joe; Moon, Ji Won; Roh, Yul; Cho, Kyu Seong

    2011-01-01

    The behavior of metal ions leaching and precipitated mineral phases of metal-rich fly ash (FA) was examined in order to evaluate microbial impacts on carbon sequestration and metal immobilization. The leaching solutions consisted of aerobic deionized water (DW) and artificial eutrophic water (AEW) that was anaerobic, organic- and mineral-rich, and higher salinity as is typical of bottom water in eutrophic algae ponds. The Fe- and Ca-rich FAs were predominantly composed of quartz, mullite, portlandite, calcite, hannebachite, maghemite, and hematite. After 86 days, only Fe and Ca contents exhibited a decrease in leaching solutions while other major and trace elements showed increasing or steady trends in preference to the type of FA and leaching solution. Ca-rich FA showed strong carbon sequestration efficiency ranging up to 32.3 g CO(2)/kg FA after 86 days, corresponding to almost 65% of biotic carbon sequestration potential under some conditions. Variations in the properties of FAs such as chemical compositions, mineral constituents as well as the type of leaching solution impacted CO(2) capture. Even though the relative amount of calcite increased sixfold in the AEW and the relative amount of mineral phase reached 37.3 wt% using Ca-rich FA for 86 days, chemical sequestration did not accomplish simultaneous precipitation and sequestration of several heavy metals.

  7. The performance of a surface-applied corrosion inhibitor for the carbon steel in saturated Ca(OH){sub 2} solutions

    SciTech Connect

    Zheng, Haibing; Li, Weihua; Ma, Fubin; Kong, Qinglin

    2014-01-15

    In the present work, the performance of an amino alcohol based surface applied inhibitor was studied by the electrochemical techniques in saturated Ca(OH){sub 2} solutions. The surface morphology of the carbon steel was observed by scanning electron microscope, and the energy diffraction spectrum was also tested. Results showed that the inhibitor used in this work demonstrated obvious inhibition efficiency on the carbon steel in saturated Ca(OH){sub 2} solutions. The inhibition mechanism of the inhibitor lies in the quick adsorption of the active component on carbon steel surface.

  8. Association between in vivo alcohol metabolism and genetic variation in pathways that metabolize the carbon skeleton of ethanol and NADH reoxidation in the Alcohol Challenge Twin Study

    PubMed Central

    Lind, Penelope A; Macgregor, Stuart; Heath, Andrew C; Madden, Pamela AF; Montgomery, Grant W; Martin, Nicholas G; Whitfield, John B

    2013-01-01

    Background Variation in alcohol metabolism affects the duration of intoxication and alcohol use. While the majority of genetic association studies investigating variation in alcohol metabolism have focused on polymorphisms in alcohol or aldehyde dehydrogenases, we have now tested for association with genes in alternative metabolic pathways that catalyze the carbon skeleton of ethanol and NADH reoxidation. Methods 950 single nucleotide polymorphisms (SNPs) spanning 14 genes (ACN9, ACSS1, ACSS2, ALDH1A1, CAT, CYP2E1, GOT1, GOT2, MDH1, MDH2, SLC25A10, SLC25A11, SLC25A12, SLC25A13) were genotyped in 352 young adults who participated in an alcohol challenge study. Traits tested were blood and breath alcohol concentration, peak alcohol concentration and rates of alcohol absorption and elimination. Allelic association was tested using quantitative univariate and multivariate methods. Results A CYP2E1 promoter SNP (rs4838767, minor allele frequency 0.008) exceeded the threshold for study-wide significance (4.01 × 10−5) for two early blood alcohol concentration (BAC), eight breath alcohol concentration (BrAC) measures and the peak BrAC. For each phenotype the minor C-allele was related to a lower alcohol concentration, most strongly for the fourth BrAC (P = 2.07 × 10−7) explaining ~8% of the phenotypic variance. We also observed suggestive patterns of association with variants in ALDH1A1 and on chromosome 17 near SLC25A11 for aspects of blood and breath alcohol metabolism. A SNP upstream of GOT1 (rs2490286) reached study-wide significance for multivariate BAC metabolism (P = 0.000040). Conclusions Overall, we did not find strong evidence that variation in genes coding for proteins that further metabolize the carbon backbone of acetaldehyde, or contribute to mechanisms for regenerating NAD from NADH, affects alcohol metabolism in our European-descent subjects. However, based on the breath alcohol data, variation in the promoter of CYP2E1 may play a role in pre

  9. Alcohol solutions of triphenyl-tetrazolium chloride as high-dose radiochromic dosimeters

    NASA Astrophysics Data System (ADS)

    Kovács, A.; Wojnárovits, L.; El-assy, N. B.; Afeefy, H. Y.; Al-Sheikhly, M.; Walker, M. L.; McLaughlin, W. L.

    1995-09-01

    The radiolytic reduction of colorless tetrazolium salts in aqueous solution to the highly colored formazan dye is a well-known acid-forming radiation chemical reaction. Radiochromic thin films and three-dimensional hydrocolloid gels have been used for imaging and mapping absorbed dose distributions. The high solubility of 2,3,5-triphenyl-tetrazolium chloride (TTC) in alcohols provides a useful liquid dosimeter (45 mM TTC in aerated ethanol) and shows a linear response of absorbance increase (λmax = 480 nm) with dose over the range 1-16 kGy. The linear molar absorption coefficient (ɛm) for the formazan at the absorption peak is 1.5 × 103 m2 mol-1, and the radiation chemical yield for the above solution is G (formazan) = 0.014 μmol J-1. The irradiation temperature coefficient is about 0.8 percent per degree Celsius rise in temperature over the temperature range 0-30 °C but is much larger between 30° and 60 °C. The unirradiated and irradiated solutions are stable over at least five days storage at normal laboratory temperature in the dark, but when stored in daylight at elevated temperature, the unirradiated solution in sealed amber glass ampoules undergoes slow photolytic dye formation, and the irradiated solution experiences initial fading and subsequent reversal (photochromism) when exposed to direct sunlight.

  10. Carbon composites with metal nanoparticles for Alcohol fuel cells

    NASA Astrophysics Data System (ADS)

    Ventrapragada, Lakshman; Siddhardha, R. S.; Podilla, Ramakrishna; Muthukumar, V. S.; Creager, Stephen; Rao, A. M.; Ramamurthy, Sai Sathish

    2015-03-01

    Graphene due to its high surface area and superior conductivity has attracted wide attention from both industrial and scientific communities. We chose graphene as a substrate for metal nanoparticle deposition for fuel cell applications. There are many chemical routes for fabrication of metal-graphene composites, but they have an inherent disadvantage of low performance due to the usage of surfactants, that adsorb on their surface. Here we present a design for one pot synthesis of gold nanoparticles and simultaneous deposition on graphene with laser ablation of gold strip and functionalized graphene. In this process there are two natural advantages, the nanoparticles are synthesized without any surfactants, therefore they are pristine and subsequent impregnation on graphene is linker free. These materials are well characterized with electron microscopy to find their morphology and spectroscopic techniques like Raman, UV-Vis. for functionality. This gold nanoparticle decorated graphene composite has been tested for its electrocatalytic oxidation of alcohols for alkaline fuel cell applications. An electrode made of this composite showed good stability for more than 200 cycles of operation and reported a low onset potential of 100 mV more negative, an important factor for direct ethanol fuel cells.

  11. Study the density, ultrasonic and compressibility of binary mixture of aqueous solution of isopropyl alcohol and mustard oil

    NASA Astrophysics Data System (ADS)

    Monupal, Suthar, B.

    2016-05-01

    The ultrasonic velocities, compressibility and bulk modulus of binary mixtures of aqueous solution of isopropyl alcohol with mustard oil have been measured at different concentrations at room temperature. The results are varied with the concentration in such a way i.e. ultrasonic velocity and Bulk Modulus is decreases with the increase in concentration and compressibility is increases with the increase in concentration of aqueous isopropyl alcohol. It is due to molecular interactions present in the mixtures.

  12. Sorption of cobalt on activated carbons from aqueous solutions

    SciTech Connect

    Paajanen, A.; Lehto, J.; Santapakka, T.; Morneau, J.P.

    1997-01-01

    The efficiencies of 15 commercially available activated carbons were tested for the separation of trace cobalt ({sup 60}Co) in buffer solutions at pH 5.0, 6.7, and 9.1. On the basis of the results four carbon products, Diahope-006, Eurocarb TN5, Hydraffin DG47, and Norit ROW Supra, were selected for further study. These carbons represented varying (low, medium and high) cobalt removal efficiencies and were prepared of three typical raw materials: peat, coconut shell, or coal. Study was made of the effects on sorption efficiencies of factors of interest in metal/radionuclide-bearing waste effluents. These factors were pH, sodium ions, borate, and citrate.

  13. Synthesis and characterization of polyvinyl alcohol based multiwalled carbon nanotube nanocomposites

    NASA Astrophysics Data System (ADS)

    Malikov, E. Y.; Muradov, M. B.; Akperov, O. H.; Eyvazova, G. M.; Puskás, R.; Madarász, D.; Nagy, L.; Kukovecz, Á.; Kónya, Z.

    2014-07-01

    Multiwalled carbon nanotubes were synthesized by chemical vapor deposition over an Fe-Co/alumina catalyst. Nanotubes were then oxidized and grafted with polyvinyl alcohol (PVA). The obtained nanostructure was characterized by Raman spectroscopy, XRD, FTIR, EDX, SEM, TEM and TGA methods. FTIR confirmed the presence of the characteristic peaks of the anticipated ester group. The formation of polymer nanocomposites based on polyvinyl alcohol and multiwalled carbon nanotubes was confirmed by SEM and TEM. High resolution electron micrographs revealed that the primary binding sites for PVA grafting are the sidewall defects of the nanotubes. The novelty of this work is the use of the Fischer esterification reaction for creating the permanent link between the nanotubes and the PVA matrix.

  14. Insights into non-Fickian solute transport in carbonates

    PubMed Central

    Bijeljic, Branko; Mostaghimi, Peyman; Blunt, Martin J

    2013-01-01

    [1] We study and explain the origin of early breakthrough and long tailing plume behavior by simulating solute transport through 3-D X-ray images of six different carbonate rock samples, representing geological media with a high degree of pore-scale complexity. A Stokes solver is employed to compute the flow field, and the particles are then transported along streamlines to represent advection, while the random walk method is used to model diffusion. We compute the propagators (concentration versus displacement) for a range of Peclet numbers (Pe) and relate it to the velocity distribution obtained directly on the images. There is a very wide distribution of velocity that quantifies the impact of pore structure on transport. In samples with a relatively narrow spread of velocities, transport is characterized by a small immobile concentration peak, representing essentially stagnant portions of the pore space, and a dominant secondary peak of mobile solute moving at approximately the average flow speed. On the other hand, in carbonates with a wider velocity distribution, there is a significant immobile peak concentration and an elongated tail of moving fluid. An increase in Pe, decreasing the relative impact of diffusion, leads to the faster formation of secondary mobile peak(s). This behavior indicates highly anomalous transport. The implications for modeling field-scale transport are discussed. Citation: Bijeljic, B., P. Mostaghimi, and M. J. Blunt (2013), Insights into non-Fickian solute transport in carbonates, Water Resour. Res., 49, 2714–2728, doi:10.1002/wrcr.20238. PMID:24223444

  15. Mutagenicity evaluation with Ames test of hydro-alcoholic solution of terpenes.

    PubMed

    Lupi, S; Marconi, S; Paiaro, E; Fochesato, A; Gregorio, P

    2009-09-01

    Mutagenic properties of terpenes (both synthesis and plant derived) have been tested, up to now, as a single molecule. A terpenes containing hydro-alcoholic solution deriving from frankincense and myrrh resins and hyssop essential oil was assayed for mutagenicity by means of ames test. Extraction technique conducted with electromagnetic fields at room temperature enabled to obtain a solution of free active molecules that did not undergo thermal degradation and characterized by biocidal activity. In order to verify lack of mutagenic hazard in coming into contact with human, the solution was appropriately diluted and tested with Salmonella typhimurium TA98, TA1535 and YG1024 strains, both in absence and in presence of metabolic system S9. For none of the tested conditions a 2-fold increase of induced revertants, as regards to spontaneous, was registered. The ratio between induced and spontaneous His+ revertants (Mutagenic Index) was around 1.00 in all the determinations and no statistically significant differences have been identified comparing the sample and the negative control. A similar result has been obtained for the dose-response curve. In conclusion, we verified that tested terpenes solution lacks of mutagenicity on Salmonella typhimurium with and without metabolic activator so this plant extract can be safely used as biocide. PMID:20411651

  16. Vitamin C hinders radiation cross-linking in aqueous poly(vinyl alcohol) solutions

    NASA Astrophysics Data System (ADS)

    Oral, Ebru; Bodugoz-Senturk, Hatice; Macias, Celia; Muratoglu, Orhun K.

    2007-12-01

    Poly(vinyl alcohol) (PVA) is a promising semi-crystalline material for biomedical applications. It is soluble in water and can be formed into hydrogels by freezing and thawing or crystallizing from an aqueous theta solution such as that of polyethylene glycol (PEG). Radiation cross-linking caused by sterilization or high dose irradiation of concentrated PVA solutions could compromise some properties of these hydrogels. Therefore, we hypothesized that radiation cross-linking of PVA solutions and PVA-PEG theta gels could be prevented by using the antioxidant vitamin C as an anticross-linking agent. Our hypothesis tested positive. Vitamin C concentrations of 0.75 and 4.5 mol/mol of PVA repeating unit could prevent cross-linking in 17.5 wt/v% PVA solutions made with PVA molecular weight of 115,000 g/mol irradiated to 25 and 100 kGy, respectively. Vitamin C also prevented cross-linking in 25 kGy irradiated PVA-PEG theta gels containing up to 5 wt% PEG and decreased the viscosity of those up to 39 wt%.

  17. Unexpected dehomologation of primary alcohols to one-carbon shorter carboxylic acids using o-iodoxybenzoic acid (IBX).

    PubMed

    Xu, Shu; Itto, Kaori; Satoh, Masahide; Arimoto, Hirokazu

    2014-03-14

    A novel and efficient transformation of primary alcohols to one-carbon shorter carboxylic acids using IBX is reported. Mechanistic studies revealed that the combination of IBX and molecular iodine produces a different active hypervalent iodine species.

  18. Hydrogenolysis of 5-carbon sugars, sugar alcohols, and other methods and compositions for reactions involving hydrogen

    DOEpatents

    Werpy, Todd A [West Richland, WA; Zacher, Alan H [Kennewick, WA

    2002-11-12

    Methods and compositions for reactions of hydrogen over a Re-containing catalyst with compositions containing a 5-carbon sugar, sugar alcohol, or lactic acid are described. It has been surprisingly discovered that reaction with hydrogen over a Re-containing multimetallic catalyst resulted in superior conversion and selectivity to desired products such as propylene glycol. A process for the synthesis of PG from lactate or lactic acid is also described.

  19. Hydrogenolysis of 5-carbon sugars, sugar alcohols, and methods of making propylene glycol

    DOEpatents

    Werpy, Todd A [West Richland, WA; Zacher, Alan H [Kennewick, WA

    2006-05-02

    Methods and compositions for reactions of hydrogen over a Re-containing catalyst with compositions containing a 5-carbon sugar, sugar alcohol, or lactic acid are described. It has been surprisingly discovered that reaction with hydrogen over a Re-containing multimetallic catalyst resulted in superior conversion and selectivity to desired products such as propylene glycol. A process for the synthesis of PG from lactate or lactic acid is also described.

  20. Hydrogenolysis Of 5-Carbon Sugars, Sugar Alcohols And Compositions For Reactions Involving Hydrogen

    DOEpatents

    Werpy, Todd A.; Frye, Jr., John G.; Zacher, Alan H.; Miller, Dennis J.

    2004-01-13

    Methods and compositions for reactions of hydrogen over a Re-containing catalyst with compositions containing a 5-carbon sugar, sugar alcohol, or lactic acid are described. It has been surprisingly discovered that reaction with hydrogen over a Re-containing multimetallic catalyst resulted in superior conversion and selectivity to desired products such as propylene glycol. A process for the synthesis of PG from lactate or lactic acid is also described.

  1. Microkinetic Modeling of Benzyl Alcohol Oxidation on Carbon-Supported Palladium Nanoparticles

    DOE PAGES

    Savara, Aditya; Rossetti, Ilenia; Chan-Thaw, Carine E.; Prati, Laura; Villa, Alberto

    2016-07-14

    Six products are formed from benzyl alcohol oxidation over Pd nanoparticles using O2 as the oxidant: benzaldehyde, toluene, benzyl ether, benzene, benzoic acid, and benzyl benzoate. Three experimental parameters were varied here: alcohol concentration, oxygen concentration, and temperature. Microkinetic modeling using a mechanism published recently with surface intermediates was able to produce all 18 trends observed experimentally with mostly quantitative agreement. Approximate analytical equations derived from the microkinetic model for isothermal conditions reproduced the isothermal trends and provided insight. The most important activation energies are Ea2=57.9 kJ mol₋1, Ea5=129 kJ mol₋1, and Ea6=175 kJ mol₋1, which correspond to alcohol dissociation,more » alkyl hydrogenation, and the reaction of alkyl species with alkoxy species. Upper limits for other activation energies were identified. The concepts of a sticking coefficient and steric factor in solution were applied.« less

  2. A carbon nanotube-infused polysulfone membrane with polyvinyl alcohol layer for treating oil-containing waste water

    PubMed Central

    Maphutha, Selby; Moothi, Kapil; Meyyappan, M.; Iyuke, Sunny E.

    2013-01-01

    A carbon nanotube (CNT) integrated polymer composite membrane with a polyvinyl alcohol barrier layer has been prepared to separate oil from water for treatment of oil-containing waste water. The CNTs were synthesised using chemical vapour deposition, and a phase inversion method was employed for the blending of the CNTs in the polymer composite solution for casting of the membrane. Relative to the baseline polymer, an increase of 119% in the tensile strength, 77% in the Young's modulus and 258% in the toughness is seen for a concentration of 7.5% CNTs in the polymer composite. The permeate through the membrane shows oil concentrations below the acceptable 10 mg/L limit with an excellent throughput and oil rejection of over 95%. PMID:23518875

  3. Radiation preparation of graphene/carbon nanotubes hybrid fillers for mechanical reinforcement of poly(vinyl alcohol) films

    NASA Astrophysics Data System (ADS)

    Ma, Hui-Ling; Zhang, Long; Zhang, Youwei; Wang, Shuojue; Sun, Chao; Yu, Hongyan; Zeng, Xinmiao; Zhai, Maolin

    2016-01-01

    Graphene/carbon nanotubes (G/CNTs) hybrid fillers were synthesized by γ-ray radiation reduction of graphene oxide (GO) in presence of CNTs. The obtained hybrid fillers with three-dimensional (3D) interconnected network structure were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). Poly(vinyl alcohol) (PVA) composite films with enhanced mechanical properties and thermal stability were subsequently prepared by solution blending of G/CNTs with PVA matrix. The tensile strength and Young's modulus of PVA composite films containing 1 wt% G/CNTs were measured to be 81.9 MPa and 3.9 GPa respectively, which were 56% and 33.6% higher than those of pure PVA. These substantial improvements could be attributed to the interconnected 3D structure of G/CNTs, homogeneous dispersion as well as the strong hydrogen-bonding interaction between G/CNTs and PVA macromolecular chains.

  4. A carbon nanotube-infused polysulfone membrane with polyvinyl alcohol layer for treating oil-containing waste water.

    PubMed

    Maphutha, Selby; Moothi, Kapil; Meyyappan, M; Iyuke, Sunny E

    2013-01-01

    A carbon nanotube (CNT) integrated polymer composite membrane with a polyvinyl alcohol barrier layer has been prepared to separate oil from water for treatment of oil-containing waste water. The CNTs were synthesised using chemical vapour deposition, and a phase inversion method was employed for the blending of the CNTs in the polymer composite solution for casting of the membrane. Relative to the baseline polymer, an increase of 119% in the tensile strength, 77% in the Young's modulus and 258% in the toughness is seen for a concentration of 7.5% CNTs in the polymer composite. The permeate through the membrane shows oil concentrations below the acceptable 10 mg/L limit with an excellent throughput and oil rejection of over 95%.

  5. Photosensitized Reduction of Carbon Dioxide in Solution Using Noble-Metal Clusters for Electron Transfer

    NASA Astrophysics Data System (ADS)

    Toshima, Naoki; Yamaji, Yumi; Teranishi, Toshiharu; Yonezawa, Tetsu

    1995-03-01

    Carbon dioxide was reduced to methane by visible-light irradiation of a solution composed of tris(bipyridine)ruthenium(III) as photosensitizer, ethylenediaminetetraacetic acid disodium salt as sacrificial reagent, methyl viologen as electron relay, and a colloidal dispersion of polymer-protected noble-metal clusters, prepared by alcohol-reduction, as catalyst. Among the noble-metal clusters examined, Pt clusters showed the highest activity for the formation of methane as well as hydrogen. In order to improve the activity, oxidized clusters and bimetallic clusters were also applied. For example, the CH4 yield in 3-h irradiation increased from 51 x 10-3 μmol with unoxidized Pt clusters to 72 x 10-3 μmol with partially oxidized ones. In the case of Pt/Ru bimetalic systems, the improvement of the catalytic activity by air treatment was much greater than in case of monometallic clusters.

  6. Frequency dependence of electron spin-lattice relaxation for semiquinones in alcohol solutions

    NASA Astrophysics Data System (ADS)

    Elajaili, Hanan B.; Biller, Joshua R.; Eaton, Sandra S.; Eaton, Gareth R.

    2014-10-01

    The spin-lattice relaxation rates at 293 K for three anionic semiquinones (2,5-di-t-butyl-1,4-benzosemiquinone, 2,6-di-t-butyl-1,4-benzosemiquinone, and 2,3,5,6-tetramethoxy-1,4-benzosemiquinone) were studied at up to 8 frequencies between 250 MHz and 34 GHz in ethanol or methanol solution containing high concentrations of OH-. The relaxation rates are about a factor of 2 faster at lower frequencies than at 9 or 34 GHz. However, in perdeuterated alcohols the relaxation rates exhibit little frequency dependence, which demonstrates that the dominant frequency-dependent contribution to relaxation is modulation of dipolar interactions with solvent nuclei. The relaxation rates were modeled as the sum of two frequency-independent contributions (spin rotation and a local mode) and two frequency-dependent contributions (modulation of dipolar interaction with solvent nuclei and a much smaller contribution from modulation of g anisotropy). The correlation time for modulation of the interaction with solvent nuclei is longer than the tumbling correlation time of the semiquinone and is consistent with hydrogen bonding of the alcohol to the oxygen atoms of the semiquinones.

  7. Carbon monoxide bioconversion to butanol-ethanol by Clostridium carboxidivorans: kinetics and toxicity of alcohols.

    PubMed

    Fernández-Naveira, Ánxela; Abubackar, Haris Nalakath; Veiga, María C; Kennes, Christian

    2016-05-01

    Butanol production from carbon monoxide-rich waste gases or syngas is an attractive novel alternative to the conventional acetone-butanol-ethanol (ABE) fermentation. Solvent toxicity is a key factor reported in ABE fermentation with carbohydrates as substrates. However, in the gas-fermentation process, kinetic aspects and the inhibition effect of solvents have not thoroughly been studied. Therefore, different batch bottle experiments were carried out with the bacterial species Clostridium carboxidivorans using CO as carbon source for butanol-ethanol fermentation. A maximum specific growth rate of 0.086 ± 0.004 h(-1) and a biomass yield of 0.011 gbiomass/gCO were found, which is significantly lower than in other clostridia grown on sugars. Besides, three assays were carried out to check the inhibitory effect of butanol, ethanol, and their mixtures. Butanol had a higher inhibitory effect on the cells than ethanol and showed a lower IC50, reduced growth rate, and slower CO consumption with increasing alcohol concentrations. A concentration of 14-14.50 g/L butanol caused 50 % growth inhibition in C. carboxidivorans, and 20 g/L butanol resulted in complete inhibition, with a growth rate of 0 h(-1). Conversely, 35 g/L ethanol decreased by 50 % the final biomass concentration respect to the control and yielded the lowest growth rate of 0.024 h(-1). The inhibitory effect of mixtures of both alcohols was also checked adding similar, near identical, concentrations of each one. Growth decreased by 50 % in the presence of a total concentration of alcohols of 16.22 g/L, consisting of similar amounts of each alcohol. Occasional differences in initially added concentrations of alcohols were minimal. The lowest growth rate (0.014 h(-1)) was observed at the highest concentration assayed (25 g/L).

  8. Spectra of copper and europium β-diketonates in alcoholic solutions and transparent dielectrics

    NASA Astrophysics Data System (ADS)

    Rybaltovskii, A. O.; Gerasimova, V. I.; Bogomolova, L. D.; Zhachkin, V. A.; Lemenovskii, D. A.; Tsypina, S. I.; Bagratashvili, V. N.

    2006-07-01

    We have used optical and EPR spectroscopy to study the mechanisms for color center formation in nanoporous glasses, polymethylmethacrylate, and alcoholic solutions containing ?-diketonate molecules: Cu(hfac)2, Ba(hfac)2, Pr(hfac)3, and Eu(fod)3. We have observed and studied the complex structure of the absorption bands in the 300 nm region belonging to the intraligand π-π* transition. Analogous results were obtained when studying the photoluminescence spectra of 5D0 → 7F0 transitions of Eu3+ ions and the EPR spectra of Cu2+ ions in matrices doped with Cu(hfac)2. We propose a model according to which for β-diketonate molecules (except for basic diketonates), a hydrolyzed form exists that is formed during synthesis of the polycrystalline powder due to the presence of water molecules. The model allows us to explain the spectral manifestations of β-diketonates in different matrices.

  9. Methylene blue adsorption from aqueous solution by activated carbon: effect of acidic and alkaline solution treatments.

    PubMed

    Ijagbemi, Christianah O; Chun, Ji I; Han, Da H; Cho, Hye Y; O, Se J; Kim, Dong S

    2010-01-01

    The removal of Methylene Blue (MB) from aqueous solution using activated carbon (AC) has been investigated. Adsorption experiments were conducted and the maximum adsorption capacity was determined. The effect of experimental parameters such as pH, dye concentration and temperature were studied on the adsorption process. Equilibrium data were mathematically modeled using the Langmuir and Freundlich adsorption models to describe the equilibrium isotherms at different dye concentrations and temperature. Parameters of best-fit model were calculated and discussed. To understand the mechanism of adsorption, kinetic models were employed to follow the adsorption processes; the pseudo-first-order best described the adsorption of MB onto AC. It was found that pH plays a major role in the adsorption process; adsorption capacity was influenced by the physical and surface chemical properties of carbon and the pH of the solution. 99.0% MB removal was achieved at equilibrium.

  10. Dissolution and mechanical behaviors of recrystallized carbamazepine from alcohol solution in the presence of additives

    NASA Astrophysics Data System (ADS)

    Nokhodchi, A.; Bolourtchian, N.; Dinarvand, R.

    2005-02-01

    Carbamazepine (CBZ) crystals were grown from pure ethanol solutions containing various additives (PEG 4000, PVP K30 or Tween 80). Physical characteristics of the crystals were studied for the morphology of crystals using scanning electron microscope, for the identification of polymorphism by X-ray powder diffraction (XRPD) and FT-IR, and for thermodynamic properties using differential scanning calorimetery (DSC). The dissolution behaviour of various carbamazepine crystals was also studied by dissolution apparatus II at pH 7.4 containing 1% sodium lauryl sulphate (SLS). The scanning electron micrograph (SEM) studies showed that the presence of the additives in the solutions growth medium affected the morphology and size of carbamazepine crystals. SEMs of untreated and treated carbamazepine crystals obtained from alcohol containing PEG 4000, PVP K30 or Tween 80 showed that the crystal shape of untreated carbamazepine is flaky or thin plate-like, whereas the crystals obtained from alcohol containing no additive, PEG 4000, PVP K30 or Tween 80 are polyhedral prismatic, block-shaped, polyhedral or hexagonal, respectively. XRPD, FT-IR and DSC results showed that the untreated CBZ was form III and recrystallization of CBZ in the absence or presence of the additives did not cause any polymorphic changes. The results showed that the higher dissolution rate and compact strength were observed for the crystals obtained in the presence of PVP K30. The presence of the additives in crystallization medium alters crystal morphology of carbamazepine, but only the samples crystallized in the presence of PVP K30 showed an improvement in dissolution rate and tensile strength.

  11. Fluidic delivery of homogeneous solutions through carbon tube bundles

    NASA Astrophysics Data System (ADS)

    Srikar, R.; Yarin, A. L.; Megaridis, C. M.

    2009-07-01

    A wide array of technological applications requires localized high-rate delivery of dissolved compounds (in particular, biological ones), which can be achieved by forcing the solutions or suspensions of such compounds through nano or microtubes and their bundled assemblies. Using a water-soluble compound, the fluorescent dye Rhodamine 610 chloride, frequently used as a model drug release compound, it is shown that deposit buildup on the inner walls of the delivery channels and its adverse consequences pose a severe challenge to implementing pressure-driven long-term fluidic delivery through nano and microcapillaries, even in the case of such homogeneous solutions. Pressure-driven delivery (3-6 bar) of homogeneous dye solutions through macroscopically-long (~1 cm) carbon nano and microtubes with inner diameters in the range 100 nm-1 µm and their bundled parallel assemblies is studied experimentally and theoretically. It is shown that the flow delivery gradually shifts from fast convection-dominated (unobstructed) to slow jammed convection, and ultimately to diffusion-limited transport through a porous deposit. The jamming/clogging phenomena appear to be rather generic: they were observed in a wide concentration range for two fluorescent dyes in carbon nano and microtubes, as well as in comparable transparent glass microcapillaries. The aim of the present work is to study the physics of jamming, rather than the chemical reasons for the affinity of dye molecules to the tube walls.

  12. carbonate solid solution at high pressures up to 55 GPa

    NASA Astrophysics Data System (ADS)

    Spivak, Anna; Solopova, Natalia; Cerantola, Valerio; Bykova, Elena; Zakharchenko, Egor; Dubrovinsky, Leonid; Litvin, Yuriy

    2014-09-01

    Magnesite, siderite and ferromagnesites Mg1- x Fe x CO3 ( x = 0.05, 0.09, 0.2, 0.4) were characterized using in situ Raman spectroscopy at high pressures up to 55 GPa. For the Mg-Fe-carbonates, the Raman peak positions of six modes (T, L, ν4, ν1, ν3 and 2ν2) in the dependence of iron content in the carbonates at ambient conditions are presented. High-pressure Raman spectroscopy shows that siderite undergoes a spin transition at ~40 GPa. The examination of the solid solutions with compositions Mg0.6Fe0.4CO3, Mg0.8Fe0.2CO3, Mg0.91Fe0.09CO3 and Mg0.95Fe0.05CO3 indicates that with increase in the amount of the Fe spin transition pressure increases up to ~45 GPa.

  13. Stereoselective carbon-carbon bond formation via the Mitsunobu displacement of chiral secondary benzylic alcohols.

    PubMed

    Hillier, Michael C; Desrosiers, Jean-Nicolas; Marcoux, Jean-François; Grabowski, Edward J J

    2004-02-19

    [reaction: see text] The stereoselective displacement of a variety of chiral benzylic alcohols with triethylmethanetricarboxylate (TEMT) under Mitsunobu conditions (DEAD, PMe(3)) has been demonstrated to proceed in good yield (70-94%) and with a high degree of inversion. Subsequent saponification and decarboxylation of the products thus obtained provide chiral 3-aryl-3-substituted propanoic acids without racemization.

  14. Direct growth of nanocrystalline graphitic carbon films on BaF2 by alcohol CVD

    NASA Astrophysics Data System (ADS)

    Tan, Yan; Nakamura, Atsushi; Kubono, Atsushi

    2016-03-01

    Multilayered nanocrystalline graphitic carbon films were directly formed on BaF2 substrates by the alcohol chemical vapor deposition method using ethanol. Domain size was typically 46 nm as estimated from the peak intensity ratios of G- and D-band of the Raman spectra, which were higher than currently reported values for various dielectric substrates. Sheet resistance measured by the four-probe method was 900 Ω/sq. A possible formation mechanism of the graphitic carbon layer was discussed referring to the results of X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDX) for a composition analysis. It was found that the graphitic carbon layers were formed on the BaO surface, which was produced by the oxidization of the BaF2 substrate by the ethanol source.

  15. Catalytic ozonation of pentachlorophenol in aqueous solutions using granular activated carbon

    NASA Astrophysics Data System (ADS)

    Asgari, Ghorban; Samiee, Fateme; Ahmadian, Mohammad; Poormohammadi, Ali; solimanzadeh, Bahman

    2014-11-01

    The efficiency of granular activated carbon (GAC) was investigated in this study as a catalyst for the elimination of pentachlorophenol (PCP) from contaminated streams in a laboratory-scale semi-batch reactor. The influence of important parameters including solution pH (2-10), radical scavenger (tert-butanol, 0.04 mol/L), catalyst dosage (0.416-8.33 g/L), initial PCP concentration (100-1000 mg/L) and ozone flow rate (2.3-12 mg/min) was examined on the efficiency of the catalytic ozonation process (COP) in degradation and mineralization of PCP in aqueous solution. The experimental results showed that catalytic ozonation with GAC was most effective at pH of 8 with ozone flow rate of 12 mg/min and a GAC dosage of 2 g. Compared to the sole ozonation process (SOP), the removal levels of PCP and COP were, 98, and 79 %, respectively. The degradation rate of kinetics was also investigated. The results showed that using a GAC catalyst in the ozonation of PCP produced an 8.33-fold increase in rate kinetic compared to the SOP under optimum conditions. Tert-butanol alcohol (TBA) was used as a radical scavenger. The results demonstrated that COP was affected less by TBA than by SOP. These findings suggested that GAC acts as a suitable catalyst in COP to remove refractory pollutants from aqueous solution.

  16. Composites of polyvinyl alcohol and carbon (coils, undoped and nitrogen doped multiwalled carbon nanotubes) as ethanol, methanol and toluene vapor sensors.

    PubMed

    Greenshields, Márcia W C C; Hümmelgen, Ivo A; Mamo, Messai A; Shaikjee, Ahmed; Mhlanga, Sabelo D; van Otterlo, Willem A L; Coville, Neil J

    2011-11-01

    We investigate the chemical sensing behavior of composites prepared with polyvinyl alcohol and carbon materials (undoped multiwalled carbon nanotubes, nitrogen-doped multiwalled carbon nanotubes and carbon nanocoils). We determine the sensitivity of thin films of these composites for ethanol, methanol and toluene vapor, comparing their conductance and capacitance responses. The composite that exhibits highest sensitivity depends on specific vapor, vapor concentration and measured electrical response, showing that the interactivity of the carbon structure with chemical species depend on structural specificities of the carbon structure and doping.

  17. MICROWAVE-ASSISTED SYNTHESIS OF CROSSLINKED POLY(VINYL ALCOHOL) NANOCOMPOSITES COMPRISING SINGLE-WALLED CARBON NANOTUBES, MULTI-WALLED CARBON NANOTUBES AND BUCKMINSTERFULLERENE

    EPA Science Inventory

    We report a facile method to accomplish cross-linking reaction of poly (vinyl alcohol) (PVA) with single-wall carbon nanotubes (SWNT), multi-wall carbon nanotubes (MWNT), and Buckminsterfullerene (C-60) using microwave (MW) irradiation. Nanocomposites of PVA cross-linked with SW...

  18. Dispersion of denatured carbon nanotubes by using a dimethylformamide solution

    NASA Astrophysics Data System (ADS)

    Thuy Nguyen, Thi; Uan Nguyen, Sy; Tam Phuong, Dinh; Chien Nguyen, Duc; Mai, Anh Tuan

    2011-09-01

    The dispersion of carbon nanotubes (CNTs) in liquid plays an important role in fundamental research and applied science. The most common technique applied to disperse CNTs is ultrasonication. The surfactants used for CNT dispersion are ethanol, sodium dodecyl benzenesulfonate (SDBS), dodecyltrimethylammonium bromide (DATB), sodium dodecyl sulfate (SDS) and sodium dodecylbenzene sulfonate (NaDDBS). This paper presents the dispersion of denatured CNTs by using a dimethylformamide (DMF) solution. The DMF is adsorbed on the surface of the nanotubes by a hydrophobic or π–π interaction. Ultrasonication helps DMF debundle the nanotubes by Coulombic or hydrophilic interaction, allowing the Van der Waals forces among the individual nanotubes to be overcome. UV–Vis spectra of dispersed CNTs in solution showed a maximum at 260 nm and decreased from UV to near IR. The vibration properties of the carbon samples were characterized with Raman spectroscopy, which illustrated the D and G bands of denatured CNTs at 1354 and 1581 cm‑1, respectively, different from the values of 1352 cm‑1 and 1580 cm‑1, respectively, for undenatured CNTs. Finally, the interaction between surfactants and nanotubes was studied by Fourier transform infrared spectroscopy (FTIR).

  19. Mesoporous Carbon Supported Rh Nanoparticle Catalysts for the Production of C2+ Alcohol from Syngas.

    PubMed

    Kim, Min-Ji; Kim, Tae-Wan; Chae, Ho-Jeong; Kim, Chul-Ung; Jeong, Soon-Yong; Kim, Jeong-Rang; Ha, Kyoung-Su

    2016-02-01

    Uniform rhodium nanoparticles (NP) with three different particle sizes (1.9, 2.4, and 3.6 nm) were prepared via a polyol method with rhodium (III) acetylacetonate, poly(vinylpyrrolidone) with different concentrations of sodium citrate. The prepared Rh nanoparticles were impregnated into the ordered mesoporous carbon supports with two different pore structures (2D hexagonal and 3D cubic). The prepared Rh nanoparticle-supported ordered mesoporous carbons (OMCs) were introduced as catalysts for the CO hydrogenation of syngas to produce C2 higher alcohols. The characteristics of the Rh nanoparticle-supported ordered mesoporous carbons catalysts were analyzed through transmission electron microscopy, powder X-ray diffraction, and N2 physisorption analysis. The catalytic tests of the catalyst were performed using a fixed-bed reactor. The results revealed that the catalysts exhibited the different catalytic activity and selectivity of higher alcohols, which could be attributed to the different OMC structures, the nanoparticle size of Rh, and aggregation of Rh nanoparticles during the reaction. PMID:27433718

  20. Solution Spinning and Characterization of Poly (vinyl alcohol) /Soybean Polyblend Fibers

    NASA Astrophysics Data System (ADS)

    Zhang, Xiefei; Kumar, Satish

    2002-03-01

    Solution Spinning and Characterization of Poly (vinyl alcohol) /Soybean Polyblend Fibers Xiefei Zhang and Satish Kumar School of Textile and Fiber Engineering Georgia Institute of Technology Atlanta GA 30032 During 1930s and 40s there was significant research activity in processing fibers from regenerated proteins. However, due to development of synthetic fibers and partially due to low tensile strength of the regenerated protein fibers, there has not been much interest in this field over last half a century. To improve strength of the regenerated protein, an attempt has been made to process PVA /soybean protein polyblend fibers. PVA/Soybean protein ratio of 100/0, 90/10, 70/30, 50/50, 40/60, 20/80 and 0/100 have been utilized. This has been done in an attempt to take advantage of the PVA/soybean interaction. Urea, sodium sulfite, as well as heat, were used to make denatured soybean protein solution, which was suitable for solution spinning. The polyblend fibers underwent post-spinning treatment, such as crosslinking, washing, drying and heat treatment. The fibers have been characterized for thermal behavior and tensile as well as dynamic mechanical properties. Blend fiber morphology was studied using scanning electron microscopy and fiber structure characterized using wide angle X-ray diffraction. Effects of draw ratio, crosslinking time, crosslinking agent, heat treatment conditions as well as PVA/soybean composition on the mechanical properties of polyblend fibers have been studied. Dynamic mechanical analysis as well as scanning electron microscopy exhibit PVA /soybean protein compatibility.

  1. Carbon nitride for the selective oxidation of aromatic alcohols in water under visible light.

    PubMed

    Long, Baihua; Ding, Zhengxin; Wang, Xinchen

    2013-11-01

    The selective oxidation of aromatic alcohols in water is achieved by using a carbon nitride (CN) catalyst, dioxygen, and visible light. The unique electronic structure of CN avoids the direct formation of hydroxyl radicals, which typically cause the total oxidation of organics. The chemical stability of CN allows several chemical protocols for photoredox catalysis in water, as exemplified by cooperative catalysis involving Brønsted acids. This leads to a new, green pathway for diverse organic transformations using sunlight and water. PMID:24039175

  2. Enhanced mechanical properties and morphological characterizations of poly(vinyl alcohol) carbon nanotube composite films

    NASA Astrophysics Data System (ADS)

    Chen, Wei; Tao, Xiaoming; Xue, Pu; Cheng, Xiaoyin

    2005-12-01

    Tensile tests were carried out on free-standing composite films of poly(vinyl alcohol) (PVA) and multiwall carbon nanotubes (MWNTs) for different loading levels. Results show that overall mechanical properties of the composite were greatly improved as compared to the neat PVA film. For PVA-based materials at significant high loading level such as 9.1 wt.% MWNTs, considerable increases in Young's modulus, tensile strength and toughness by factors of 4.5, 2.7 and 4.1, respectively, were achieved. Raman, SEM, TEM, and DSC techniques were used to evaluate the PVA/MWNTs composite system. Strong acid-modification of the pristine MWNTs and the subsequent ultrasonication processing allowed good distribution of the nanotubes in the matrix. SEM together with DSC result shows apparent good wetting of the nanotubes by the PVA matrix, which are supportive of good interfacial bonding between the modified carbon nanotubes and the hosting polymer matrix.

  3. Asymmetric supercapacitor based on nanostructured graphene foam/polyvinyl alcohol/formaldehyde and activated carbon electrodes

    NASA Astrophysics Data System (ADS)

    Bello, Abdulhakeem; Barzegar, Farshad; Momodu, Damilola; Dangbegnon, Julien; Taghizadeh, Fatemeh; Fabiane, Mopeli; Manyala, Ncholu

    2015-01-01

    We present the electrochemical results of highly porous and interconnected carbon material by activation of graphene foam/polyvinyl alcohol-formaldehyde composite material designated as GF/PVA-F. Asymmetric supercapacitor devices were fabricated using the activated material (GF/PVA-F) and activated carbon (AC) as the positive and negative electrodes respectively. The device exhibited a maximum energy density of 42 mWh cm-2, a power density of 0.5 W cm-2 and 98% retention of its initial capacitance after 2000 cycles in an extended cell potential window of 1.8 V in 1 M Na2SO4 aqueous electrolyte. This work shows the great potential of this material for high performance energy storage application.

  4. Aggregation in dilute aqueous tert-butyl alcohol solutions: Insights from large-scale simulations

    NASA Astrophysics Data System (ADS)

    Gupta, Rini; Patey, G. N.

    2012-07-01

    Molecular dynamics simulations employing up to 64 000 particles are used to investigate aggregation and microheterogeneity in aqueous tert-butyl alcohol (TBA) solutions for TBA mole fractions Xt ⩽ 0.1. Four different force fields are considered. It is shown that the results obtained can be strongly dependent on the particular force field employed, and can be significantly influenced by system size. Two of the force fields considered show TBA aggregation in the concentration range Xt ≈ 0.03 - 0.06. For these models, systems of 64 000 particles are minimally sufficient to accommodate the TBA aggregates. The structures resulting from TBA aggregation do not have a well-defined size and shape, as one might find in micellar systems, but are better described as TBA-rich and water-rich regions. All pair correlation functions exhibit long-range oscillatory behavior with wavelengths that are much larger than molecular length scales. The oscillations are not strongly damped and the correlations can easily exceed the size of the simulation cell, even for the low TBA concentrations considered here. We note that these long-range correlations pose a serious problem if one wishes to obtain certain physical properties such as Kirkwood-Buff integrals from simulation results. In contrast, two other force fields that we consider show little sign of aggregation for Xt ≲ 0.08. In our 64 000 particle simulations all four models considered show demixing-like behavior for Xt ≳ 0.1, although such behavior is not evident in smaller systems of 2000 particles. The meaning of the demixing-like behavior is unclear. Since real TBA-water solutions do not demix, it might be an indication that all four models we consider poorly represent the real system. Alternatively, it might be an artifact of finite system size. Possibly, the apparent demixing indicates that for Xt ≳ 0.1, the stable TBA aggregates are simply too large to fit into the simulation cell. Our results provide a view of the

  5. Hydrophobic Hydration in Water-tert-Butyl Alcohol Solutions by Extended Depolarized Light Scattering.

    PubMed

    Comez, L; Paolantoni, M; Lupi, L; Sassi, P; Corezzi, S; Morresi, A; Fioretto, D

    2015-07-23

    Molecular dynamics and structural properties of water-tert-butyl alcohol (TBA) mixtures are studied as a function of concentration by extended depolarized light scattering (EDLS) experiments. The wide frequency range, going from fraction to several thousand GHz, explored by EDLS allows distinguishing TBA rotational dynamics from structural relaxation of water and intermolecular vibrational and librational modes of the solution. Contributions to the water relaxation originating from two distinct populations, i.e. hydration and bulk water, are clearly identified. The dynamic retardation factor of hydration water with respect to the bulk, ξ ≈ 4, almost concentration independent, is one of the smallest found by EDLS among a variety of systems of different nature and complexity. This result, together with the small number of water molecules perturbed by the presence of TBA, supports the idea that hydrophobic simple molecules are less effective than hydrophilic and more complex molecules in perturbing the H-bond network of liquid water. At increasing TBA concentrations the average number of perturbed water molecules shows a pronounced decrease and the characteristic frequency of librational motions reduces significantly, both of which are results consistent with the occurrence of self-aggregation of TBA molecules.

  6. Time-resolved spectroscopy of the singlet excited state of betanin in aqueous and alcoholic solutions.

    PubMed

    Wendel, Monika; Nizinski, Stanislaw; Tuwalska, Dorota; Starzak, Karolina; Szot, Dominika; Prukala, Dorota; Sikorski, Marek; Wybraniec, Slawomir; Burdzinski, Gotard

    2015-07-21

    The photophysical properties of betanin in aqueous and alcoholic solutions were determined at room temperature using ultrafast UV-vis-NIR transient absorption spectroscopy (λexc = 535 nm). Its S1 → Sn (n > 1) absorption bands appear with maxima at about λ ∼ 450 and 1220 nm. The short betanin S1 state lifetime (6.4 ps in water) is mainly determined by the efficient S1 → S0 radiationless relaxation, probably requiring a strong change in geometry, since the S1 lifetime grows to 27 ps in the more viscous ethylene glycol. The fluorescence quantum yield is very low (Φf ∼ 0.0007 in water), therefore this deactivation path is of minor importance. Other processes, such as S1 → T1 intersystem crossing or photoproduct formation, are virtually absent, since full S0 ← S1 ground state recovery is observed within tens of picoseconds after photoexcitation. The observed fast light-to-heat conversion in the absence of triplet excited state formation supports the idea that betanin is a photoprotector in vivo.

  7. Removal of Uranium From Aqueous Solution by Carbon Nanotubes.

    PubMed

    Yu, Jing; Wang, Jianlong

    2016-10-01

    The adsorption of uranium onto carbon nanotubes (CNTs) was investigated. The effect of solution pH, contact time, initial uranium concentration, and temperature on the adsorption capacity of uranium was determined. CNTs were characterized by using scanning electron microscopy (SEM), transmission electron microscopy (TEM), powder x-ray diffraction (XRD), Raman spectra, and the Fourier infrared spectra (FTIR). The diameters of the CNTs varied from 10 to 50 nm in diameter and 1 ~ 2 μm in length. FTIR spectra analysis indicated that carboxyl groups were involved in adsorption of U(VI) by CNTs. The experimental results showed that U(VI) adsorption onto CNTs reached equilibrium within 10 min, and the removal efficiency was 95% at pH = 5. The adsorption kinetics of U(VI) could be described by a pseudo first-order kinetic model. The adsorption isotherm conformed to the Slips model. The adsorption process was spontaneous and endothermic. PMID:27575349

  8. Alcoholic beverages and carbonated soft drinks: consumption and gastrointestinal cancer risks.

    PubMed

    Cuomo, Rosario; Andreozzi, Paolo; Zito, Francesco Paolo

    2014-01-01

    Alcoholic beverages (ABs) and carbonated soft drinks (CSDs) are widely consumed worldwide. Given the high consumption of these beverages, the scientific community has increased its focus on their health impact. There is epidemiological evidence of a causal association between AB intake and digestive cancer, but the role of alcohol in determining cancer is not fully defined. Experimental studies have so far identified multiple mechanisms involved in carcinogenesis; ethanol itself is not carcinogenic but available data suggest that acetaldehyde (AA) and reactive oxygen species-both products of ethanol metabolism-have a genotoxic effect promoting carcinogenesis. Other carcinogenetic mechanisms include nutritional deficits, changes in DNA methylation, and impaired immune surveillance. As CSDs are often suspected to cause certain gastrointestinal disorders, consequently, some researchers have hypothesized their involvement in gastrointestinal cancers. Of all the ingredients, carbon dioxide is prevalently involved in the alteration of gastrointestinal physiology by a direct mucosal effect and indirect effects mediated by the mechanical pressure determined by gas. The role of sugar or artificial sweeteners is also debated as factors involved in the carcinogenic processes. However, several surveys have failed to show any associations between CSDs and esophageal, gastric, or colon cancers. On the other hand, a slight correlation between risk of pancreatic cancer and CSD consumption has been found.

  9. Investigation of Si(h k l) surfaces etched in KOH solutions saturated with tertiary-butyl alcohol

    NASA Astrophysics Data System (ADS)

    Rola, K. P.; Zubel, I.

    2011-11-01

    Anisotropic etching of silicon in KOH solutions saturated with tertiary-butyl alcohol (tert-butanol) was studied in this paper. The influence of KOH concentration of the solution with tert-butanol on Si(1 0 0) surface roughness and convex corners undercut were examined. It was shown that the largest reduction of convex corner undercut is achievable at low (3 M) concentration of KOH, at which, though, the (1 0 0) surface is densely covered with hillocks. The study on etch rate anisotropy and surface morphology of silicon substrates with different crystallographic orientations etched in 3 M KOH solutions with tert-butanol was conducted. The advantage of tert-butanol over isopropanol in terms of shaping three-dimensional structures in the (2 2 1) substrate was presented. The impact of agitation of the etching solution on roughness of (1 1 0) and (h h 1) surfaces and the distribution of hillocks on (1 0 0) and (h 1 1) surfaces were shown. Based on surface tension measurements and theoretical considerations, an adsorption explanation of the visible difference in (1 0 0) surface morphologies in the case of solutions saturated with tert-butanol and isopropanol was proposed. The KOH solution with tert-butanol could be particularly useful for texturing Si(1 0 0) surfaces, due to the possibility of achieving a dense surface coverage with hillocks in the solution saturated with the alcohol.

  10. Adsorption of methylene blue and Congo red from aqueous solution by activated carbon and carbon nanotubes.

    PubMed

    Szlachta, M; Wójtowicz, P

    2013-01-01

    This study was conducted to determine the adsorption removal of dyes by powdered activated carbon (PAC, Norit) and multi-walled carbon nanotubes (MWCNTs, Chinese Academy of Science) from an aqueous solution. Methylene blue (MB) and Congo red (CR) were selected as model compounds. The adsorbents tested have a high surface area (PAC 835 m(2)/g, MWCNTs 358 m(2)/g) and a well-developed porous structure which enabled the effective treatment of dye-contaminated waters and wastewaters. To evaluate the capacity of PAC and MWCNTs to adsorb dyes, a series of batch adsorption experiments was performed. Both adsorbents exhibited a high adsorptive capacity for MB and CR, and equilibrium data fitted well with the Langmuir model, with the maximum adsorption capacity up to 400 mg/g for MB and 500 mg/g for CR. The separation factor, RL, revealed the favorable nature of the adsorption process under experimental conditions. The kinetics of adsorption was studied at various initial dye concentrations and solution temperatures. The pseudo-second-order model was used for determining the adsorption kinetics of MB and CR. The data obtained show that adsorption of both dyes was rapid in the initial stage and followed by slower processing to reach the plateau. The uptake of dyes increased with contact time, irrespective of their initial concentration and solution temperature. However, changes in the solution temperature did not significantly influence dye removal.

  11. Adsorption of methylene blue and Congo red from aqueous solution by activated carbon and carbon nanotubes.

    PubMed

    Szlachta, M; Wójtowicz, P

    2013-01-01

    This study was conducted to determine the adsorption removal of dyes by powdered activated carbon (PAC, Norit) and multi-walled carbon nanotubes (MWCNTs, Chinese Academy of Science) from an aqueous solution. Methylene blue (MB) and Congo red (CR) were selected as model compounds. The adsorbents tested have a high surface area (PAC 835 m(2)/g, MWCNTs 358 m(2)/g) and a well-developed porous structure which enabled the effective treatment of dye-contaminated waters and wastewaters. To evaluate the capacity of PAC and MWCNTs to adsorb dyes, a series of batch adsorption experiments was performed. Both adsorbents exhibited a high adsorptive capacity for MB and CR, and equilibrium data fitted well with the Langmuir model, with the maximum adsorption capacity up to 400 mg/g for MB and 500 mg/g for CR. The separation factor, RL, revealed the favorable nature of the adsorption process under experimental conditions. The kinetics of adsorption was studied at various initial dye concentrations and solution temperatures. The pseudo-second-order model was used for determining the adsorption kinetics of MB and CR. The data obtained show that adsorption of both dyes was rapid in the initial stage and followed by slower processing to reach the plateau. The uptake of dyes increased with contact time, irrespective of their initial concentration and solution temperature. However, changes in the solution temperature did not significantly influence dye removal. PMID:24292474

  12. Polihexanide solution is more efficient than alcohol to remove phenol in chemical matricectomy: an in vitro study.

    PubMed

    Cordoba Diaz, Damian; Becerro de Bengoa Vallejo, Ricardo; Losa Iglesias, Marta Elena; Cordoba Diaz, Manuel

    2014-01-01

    For treatment of ingrown toenails, a phenolization approach is often chosen. Many reports describe a lavage of the wound with alcohol to neutralize any residual phenol; however, it remains uncertain if there is a more effective solution for use in the lavage step. The aim of our study was to analyze the suitability and effectiveness of 0.1% polihexanide solution compared with isopropyl alcohol in the removal of excess phenol after treatment for ingrown toenails. We performed an in vitro study using human matrix and a diffusion cell apparatus to measure the amount of phenol remaining after two lavage washes. The effect of phenol evaporation was also examined.When phenol was irrigated with alcohol alone, 27.43 ± 4.10 mg (57.74%) of the initial amount of phenol was recovered. If irrigated with 0.1% polihexanide, 35.98 ± 2.93 mg (75.74%) of phenol was recovered. These results indicate that a polihexanide lavage step has significantly higher efficiency for removing excess phenol relative to alcohol.

  13. Inter-Strain Differences in Liver Injury and One-Carbon Metabolism in Alcohol-Fed Mice

    PubMed Central

    Tsuchiya, Masato; Ji, Cheng; Kosyk, Oksana; Shymonyak, Svitlana; Melnyk, Stepan; Kono, Hiroshi; Tryndyak, Volodymyr; Muskhelishvili, Levan; Pogribny, Igor P.; Kaplowitz, Neil; Rusyn, Ivan

    2012-01-01

    Alcoholic liver injury is a major public health issue worldwide. Even though the major mechanisms of this disease have been established over the past decades, little is known about genetic susceptibility factors that may predispose individuals who abuse alcoholic beverages to liver damage and subsequent pathological conditions. We hypothesized that a panel of genetically diverse mouse strains may be used to examine the role of ER stress and one-carbon metabolism in the mechanism of inter-individual variability in alcoholic liver injury. We administered alcohol (up to 27 mg/kg/d) in high fat diet using intragastric intubation model for 28 days to male mice from 14 inbred strains (129S1/SvImJ, AKR/J, BALB/cJ, BALB/cByJ, BTBR T+tf/J, C3H/HeJ, C57BL/10J, DBA/2J, FVB/NJ, KK/HIJ, MOLF/EiJ, NZW/LacJ, PWD/PhJ, and WSB/EiJ). Profound inter-strain differences (more than 3-fold) in alcohol-induced steatohepatitis were observed among the strains in spite of consistently high levels of urine alcohol that was monitored throughout the study. We found that endoplasmic reticulum stress genes were induced only in strains with the highest liver injury. Liver glutathione and methyl donor levels were affected in all strains, albeit to a different degree. Most pronounced effects that were closely associated with the degree of liver injury were hyperhomocysteinemia and strain-dependent differences in expression patterns of one-carbon metabolism-related genes. Conclusion Our data demonstrate that strain differences in alcohol-induced liver injury and steatosis are striking and independent of alcohol exposure and the most severely affected strains exhibit major differences in the expression of ER stress markers and genes of one-carbon metabolism. PMID:22307928

  14. Spray-on polyvinyl alcohol separators and impact on power production in air-cathode microbial fuel cells with different solution conductivities.

    PubMed

    Hoskins, Daniel L; Zhang, Xiaoyuan; Hickner, Michael A; Logan, Bruce E

    2014-11-01

    Separators are used to protect cathodes from biofouling and to avoid electrode short-circuiting, but they can adversely affect microbial fuel cell (MFC) performance. A spray method was used to apply a polyvinyl alcohol (PVA) separator to the cathode. Power densities were unaffected by the PVA separator (339±29mW/m(2)), compared to a control lacking a separator in a low conductivity solution (1mS/cm) similar to wastewater. Power was reduced with separators in solutions typical of laboratory tests (7-13mS/cm), compared to separatorless controls. The PVA separator produced more power in a separator assembly (SEA) configuration (444±8mW/m(2)) in the 1mS/cm solution, but power was reduced if a PVA or wipe separator was used in higher conductivity solutions with either Pt or activated carbon catalysts. Spray and cast PVA separators performed similarly, but the spray method is preferred as it was easier to apply and use.

  15. Carbon Footprint of Telemedicine Solutions - Unexplored Opportunity for Reducing Carbon Emissions in the Health Sector

    PubMed Central

    Holmner, Åsa; Ebi, Kristie L.; Lazuardi, Lutfan; Nilsson, Maria

    2014-01-01

    Background The healthcare sector is a significant contributor to global carbon emissions, in part due to extensive travelling by patients and health workers. Objectives To evaluate the potential of telemedicine services based on videoconferencing technology to reduce travelling and thus carbon emissions in the healthcare sector. Methods A life cycle inventory was performed to evaluate the carbon reduction potential of telemedicine activities beyond a reduction in travel related emissions. The study included two rehabilitation units at Umeå University Hospital in Sweden. Carbon emissions generated during telemedicine appointments were compared with care-as-usual scenarios. Upper and lower bound emissions scenarios were created based on different teleconferencing solutions and thresholds for when telemedicine becomes favorable were estimated. Sensitivity analyses were performed to pinpoint the most important contributors to emissions for different set-ups and use cases. Results Replacing physical visits with telemedicine appointments resulted in a significant 40–70 times decrease in carbon emissions. Factors such as meeting duration, bandwidth and use rates influence emissions to various extents. According to the lower bound scenario, telemedicine becomes a greener choice at a distance of a few kilometers when the alternative is transport by car. Conclusions Telemedicine is a potent carbon reduction strategy in the health sector. But to contribute significantly to climate change mitigation, a paradigm shift might be required where telemedicine is regarded as an essential component of ordinary health care activities and not only considered to be a service to the few who lack access to care due to geography, isolation or other constraints. PMID:25188322

  16. Experimental fractionation of stable carbon isotopes during degassing of carbon dioxide and precipitation of calcite from aqueous solutions

    NASA Astrophysics Data System (ADS)

    Müller, K.; Winde, V.; Escher, P.; von Geldern, R.; Böttcher, M. E.

    2012-04-01

    Processes in the carbonate system of surface waters are in particular sensitive to variations of boundary conditions as, for instance, the partial pressure of carbon dioxide in the atmosphere and the aqueous solution. Examples range from streams, rivers, to coastal marine waters. The flux of carbon dioxide from continental flowing waters was recently included into calculations of the global carbon budget (Butman & Raymond, 2011, Nature Geo.). These solutions, are often supersaturated in carbon dioxide with respect to the atmosphere. The degassing of carbon dioxide is associated with a kinetically controlled fractionation of the stable carbon isotopes, which has to be considered in balancing water-air carbon dioxide fluxes. The degassing process additionally leads to the super-saturation of the aqueous solution with respect to calcium carbonate. Stable isotope fractionation is of particular value to identify and quantify processes at the water-gas phase interface and link these non-equilibrium processes to the formation mechanisms of calcite and the hydrodynamics of surface waters. Experiments were carried out with or without inert N2 gas flow to degas carbon dioxide from initially supersaturated solutions. Natural solutions used are from different stations of the Elbe estuary, the Jade Bay, the backbarrier tidal area of Spiekeroog Island, carbonate springs of Rügen Island, and the Baltic Sea coastline. Results are compared experiments using bottled mineral waters. By following the (physico) chemical changes in the solutions (pH, TA, Ca PHREEQC modeling) it was found, that two evolutionary stages can be differentiated. Reaction progress led to the preferential liberation of carbon dioxide containing the light carbon isotope, following a Rayleigh-type process. After an induction period, where only degassing of carbon dioxide took place, a second stage was observed where calcite began to form from the highly supersaturated solutions. In this stage the carbonate

  17. Stable TEMPO and ABNO Catalyst Solutions for User-Friendly (bpy)Cu/Nitroxyl-Catalyzed Aerobic Alcohol Oxidation.

    PubMed

    Steves, Janelle E; Stahl, Shannon S

    2015-11-01

    Two solutions, one consisting of bpy/TEMPO/NMI and the other bpy/ABNO/NMI (bpy =2,2'-bipyridyl; TEMPO = 2,2,6,6-tetramethylpiperidine N-oxyl, ABNO = 9-azabicyclo[3.3.1]nonane N-oxyl; NMI = N-methylimidazole), in acetonitrile are shown to have good long-term stability (≥1 year) under air at 5 °C. The solutions may be combined in appropriate quantities with commercially available [Cu(MeCN)4]OTf to provide a convenient catalyst system for the aerobic oxidation of primary and secondary alcohols.

  18. Stable TEMPO and ABNO Catalyst Solutions for User-Friendly (bpy)Cu/Nitroxyl-Catalyzed Aerobic Alcohol Oxidation.

    PubMed

    Steves, Janelle E; Stahl, Shannon S

    2015-11-01

    Two solutions, one consisting of bpy/TEMPO/NMI and the other bpy/ABNO/NMI (bpy =2,2'-bipyridyl; TEMPO = 2,2,6,6-tetramethylpiperidine N-oxyl, ABNO = 9-azabicyclo[3.3.1]nonane N-oxyl; NMI = N-methylimidazole), in acetonitrile are shown to have good long-term stability (≥1 year) under air at 5 °C. The solutions may be combined in appropriate quantities with commercially available [Cu(MeCN)4]OTf to provide a convenient catalyst system for the aerobic oxidation of primary and secondary alcohols. PMID:26457658

  19. [Disinfection efficacy of hand hygiene based on chlorhexidine gluconate content and usage of alcohol-based hand-rubbing solution].

    PubMed

    Tanaka, Ippei; Watanabe, Kiyoshi; Nakaminami, Hidemasa; Azuma, Chihiro; Noguchi, Norihisa

    2014-01-01

    Recently, the procedure for surgical hand hygiene has been switching to a two-stage method and hand-rubbing method from the traditional hand-scrubbing method. Both the two-stage and hand-rubbing methods use alcohol-based hand-rubbing after hand washing. The former requires 5 min of antiseptic hand washing, and the latter 1 min of nonantiseptic hand washing. For a prolonged bactericidal effect in terms of surgical hand hygiene, chlorhexidine gluconate (CHG) has been noted due to its residual activity. However, no detailed study comparing the disinfection efficacy and prolonged effects according to different contents of CHG and the usage of alcohol-based hand-rubbing has been conducted. The glove juice method is able to evaluate disinfection efficacy and prolonged effects of the disinfectants more accurately because it can collect not only transitory bacteria but also normal inhabitants on hands. In the present study, we examined the disinfection efficacy and prolonged effects on alcohol-based hand-rubbing containing CHG by six hand-rubbing methods and three two-stage methods using the glove juice method. In both methods, 3 mL (one pump dispenser push volume) alcohol-based hand-rubbing solution containing 1% (w/v) CHG showed the highest disinfection efficacy and prolonged effects, and no significant difference was found between the hand-rubbing and two-stage methods. In the two methods of hand hygiene, the hand-rubbing method was able to save time and cost. Therefore, the data strongly suggest that the hand-rubbing method using a one pump dispenser push volume of alcohol-based hand-rubbing solution containing 1% (w/v) CHG is suitable for surgical hand hygiene. PMID:25366919

  20. A mesoporous carbon-supported Pt nanocatalyst for the conversion of lignocellulose to sugar alcohols.

    PubMed

    Park, Dae Sung; Yun, Danim; Kim, Tae Yong; Baek, Jayeon; Yun, Yang Sik; Yi, Jongheop

    2013-12-01

    The conversion of lignocellulose is a crucial topic in the renewable and sustainable chemical industry. However, cellulose from lignocellulose is not soluble in polar solvents, and is, therefore, difficult to convert into value-added chemicals. A strategy to overcome this drawback is the use of mesoporous carbon, which enhances the affinity between the cellulose and the catalyst through its abundant functional groups and large uniform pores. Herein, we report on the preparation of a Pt catalyst supported on a type of 3D mesoporous carbon inspired by Echinometra mathae (Pt/CNE) to enhance the interaction between the catalyst and a nonsoluble reactant. In the hydrolytic hydrogenation of cellulose, the abundant oxygen groups of CNE facilitated the access of cellulose to the surface of the catalyst, and the open pore structure permits cello-oligomers to effectively diffuse to the active sites inside the pore. The highly dispersed Pt performed dual roles: hydrolysis by in situ generating protons from H2 or water as well as effective hydrogenation. The use of the Pt/CNE catalyst resulted in an approximately 80 % yield of hexitol, the best performance reported to date. In direct conversion of hardwood powder, the Pt/CNE shows good performance in the production of sugar alcohols (23 % yield). We expect that the open-structured 3D carbon will be widely applied to the conversion of various lignocellulosic materials. PMID:24227502

  1. Dual Catalysis Using Boronic Acid and Chiral Amine: Acyclic Quaternary Carbons via Enantioselective Alkylation of Branched Aldehydes with Allylic Alcohols.

    PubMed

    Mo, Xiaobin; Hall, Dennis G

    2016-08-31

    A ferrocenium boronic acid salt activates allylic alcohols to generate transient carbocations that react with in situ-generated chiral enamines from branched aldehydes. The optimized conditions afford the desired acyclic products embedding a methyl-aryl quaternary carbon center with up to 90% yield and 97:3 enantiomeric ratio, with only water as the byproduct. This noble-metal-free method complements alternative methods that are incompatible with carbon-halogen bonds and other sensitive functional groups. PMID:27518200

  2. Structural and phase transition changes of sodium dodecyl sulfate micellar solution in alcohols probed by small-angle neutron scattering (SANS)

    SciTech Connect

    Putra, Edy Giri Rachman; Patriati, Arum

    2015-04-16

    Small-angle neutron scattering (SANS) measurements on 0.3M sodium dodecyl sulfate (SDS) micellar solutions have been performed in the presence of n-alcohols, from ethanol to decanol at different alcohol concentrations, 2–10 wt%. The ellipsoid micellar structure which occurred in the 0.3M SDS in aqueous solution with the size range of 30–50 Å has different behavior at various hydrocarbon chain length and concentration of alcohols. At low concentration and short chain-length of alcohols, such as ethanol, propanol, and butanol, the size of micelles reduced and had a spherical-like structure. The opposite effect occurred as medium to long chain alcohols, such as hexanol, octanol and decanol was added into the 0.3M SDS micellar solutions. The micelles structure changed to be more elongated in major axis and then crossed the critical phase transition from micellar solution into liquid crystal phase as lamellar structure emerged by further addition of alcohols. The inter-lamellar distances were also depending on the hydrocarbon chain length and concentration of alcohols. In the meantime, the persistent micellar structures occurred in addition of medium chain of n-alcohol, pentanol at all concentrations.

  3. Porous carbon materials synthesized using IRMOF-3 and furfuryl alcohol as precursor

    NASA Astrophysics Data System (ADS)

    Deka, Pemta Tia; Ediati, Ratna

    2016-03-01

    IRMOF-3 crystals have been synthesized using solvothermal method by adding zinc nitrate hexahydrate with 2-amino-1,4-benzenedicarboxylic acid in N'N-dimethylformamide (DMF) at 100°C for 24 (note as IR-24) and 72 h (note as IR-72). The obtained crystals were characterized using X-ray Diffraction (XRD), SEM (Scanning Electron Microscopy) and Scanning Electron Microscopy-Energy Dispersive X-ray (SEM-EDX), FTIR and Isothermal adsorption-desorption N2. The diffractogram solids synthesized show characteristic peak at 2θ 6.8, 9.6 and 13.7°. SEM micrograph show cubic shape of IRMOF-3 crystal. Based on FTIR characterization, IRMOF-3 appear at wavelength (1691,46; 1425,3; 1238,21; 1319,22 dan 3504,42)cm-1. The Isotherm of crystal IRMOF-3 at heating time 24 h and 72 h are type IV. The surface area of IR-24 and IR-72 are respectively 24,758 m2/g and 29,139 m2/g with its dominant mesopores. Carbonaceous materials has been successfully synthesized using IR-24, IR-72 and furfuryl alcohol (FA) as second carbon precursor with variation of carbonation temperature 550, 700 and 850°C. The XRD result from both carbonaceous materials show formation of amorphous carbon and caharacteristic peak of ZnO oxide. Micrograph SEM show that carbonaceous materials have cubic shape as IRMOF-3 and SEM-EDX result indicate Zn and nitrogen content of these materials has decrease until temperature 850°C. Porous carbon using IR-24 and FA (notes as C-24) has increased surface area with higher carbonation temperature. The highest surface area is 1495,023 m2/g. Total pore volume and pore size of C-24 from low to high temperature respectively as (0,338; 0,539 and 1,598) cc/g; (0,107; 0,152 and 0,610) cc/g. Porous carbon using IR-72 and FA (notes as C-72) has smaller surface area than C-24 but its also increased during higher carbonation heating. The highest surface area is 1029,668 m2/g.The total pore volume and pore size of these carbon materials from low to high temperature respectively as (0,390; 0

  4. Effect of Acid and Alcohol Network Forces within Functionalized Multiwall Carbon Nanotubes Bundles on Adsorption of Copper (II) Species

    EPA Science Inventory

    Adsorption of metals on carbon nanotubes (CNTs) has important applications in sensors, membranes, and water treatment. The adsorptive capacity of multiwall CNTs for copper species in water depends on the type of functional group present on their surface. The alcohol (COOH) and ac...

  5. One-Carbon Homologation of Primary Alcohols to Carboxylic Acids, Esters, and Amides via Mitsunobu Reactions with MAC Reagents.

    PubMed

    Kagawa, Natsuko; Nibbs, Antoinette E; Rawal, Viresh H

    2016-05-20

    A method is reported for the one-carbon homologation of an alcohol to the extended carboxylic acid, ester, or amide. The process involves the Mitsunobu reaction with an alkoxymalononitrile, followed by unmasking in the presence of a suitable nucleophile. The homologation and unmasking can even be performed in a one-pot process in high yield. PMID:27135854

  6. Preparation of novel carbon microfiber/carbon nanofiber-dispersed polyvinyl alcohol-based nanocomposite material for lithium-ion electrolyte battery separator.

    PubMed

    Sharma, Ajit K; Khare, Prateek; Singh, Jayant K; Verma, Nishith

    2013-04-01

    A novel nanocomposite polyvinyl alcohol precursor-based material dispersed with the web of carbon microfibers and carbon nanofibers is developed as lithium (Li)-ion electrolyte battery separator. The primary synthesis steps of the separator material consist of esterification of polyvinyl acetate to produce polyvinyl alcohol gel, ball-milling of the surfactant dispersed carbon micro-nanofibers, mixing of the milled micron size (~500 nm) fibers to the reactant mixture at the incipience of the polyvinyl alcohol gel formation, and the mixing of hydrophobic reagents along with polyethylene glycol as a plasticizer, to produce a thin film of ~25 μm. The produced film, uniformly dispersed with carbon micro-nanofibers, has dramatically improved performance as a battery separator, with the ion conductivity of the electrolytes (LiPF6) saturated film measured as 0.119 S-cm(-1), approximately two orders of magnitude higher than that of polyvinyl alcohol. The other primary characteristics of the produced film, such as tensile strength, contact angle, and thermal stability, are also found to be superior to the materials made of other precursors, including polypropylene and polyethylene, discussed in the literature. The method of producing the films in this study is novel, simple, environmentally benign, and economically viable.

  7. Alkaline direct ethanol fuel cell performance using alkali-impregnated polyvinyl alcohol/functionalized carbon nano-tube solid electrolytes

    NASA Astrophysics Data System (ADS)

    Huang, Chien-Yi; Lin, Jia-Shiun; Pan, Wen-Han; Shih, Chao-Ming; Liu, Ying-Ling; Lue, Shingjiang Jessie

    2016-01-01

    This study investigates the application of a polyvinyl alcohol (PVA)/functionalized carbon nano-tubes (m-CNTs) composite in alkaline direct ethanol fuel cells (ADEFC). The m-CNTs are functionalized with PVA using the ozone mediation method, and the PVA composite containing the modified CNTs is prepared. Adding m-CNT into the PVA matrix enhances the alkaline uptake and the ionic conductivity of the KOH-doped electrolyte. Meanwhile, the m-CNT-containing membrane exhibited a lower swelling ratio and suppressed ethanol permeability compared to the pristine PVA film. The optimal condition for the ADEFC is determined to be under operation at an anode feed of 3 M ethanol in a 5 M KOH solution (at a flow rate of 5 cm3 min-1) with a cathode feed of moisturized oxygen (with a flow rate of 100 cm3 min-1) and the KOH-doped PVA/m-CNT electrolyte. We achieved a peak power density value of 65 mW cm-2 at 60 °C, which is the highest among the ADEFC literature data and several times higher than the proton-exchange direct ethanol fuel cells using sulfonated membrane electrolytes. Therefore, the KOH-doped PVA/m-CNT electrolyte is a suitable solid electrolyte for ADEFCs and has potential for commercialization in alkaline fuel cell applications.

  8. On the black carbon problem and its solutions

    NASA Astrophysics Data System (ADS)

    Jacobson, M. Z.

    2010-12-01

    Black carbon (BC) warms air temperatures in at least seven major ways: (a) directly absorbing downward solar radiation, (b) absorbing upward reflected solar radiation when it is situated above bright surfaces, such as snow, sea ice, and clouds, (c) absorbing some infrared radiation, (d) absorbing additional solar and infrared radiation upon obtaining a coating, (e) absorbing radiation multiply reflected within clouds when situated interstitially between cloud drops, (f) absorbing additional radiation when serving as CCN or scavenged inclusions within cloud drops, and (g) absorbing solar radiation when deposited on snow and sea ice, reducing the albedos of both. Modeling of the climate effects of BC requires treatment of all these processes in detail. In particular, treatment of BC absorption interstitially between cloud drops and from multiply-dispersed cloud drop BC inclusions must be treated simultaneously with treatment of cloud indirect effects to determine the net effects of BC on cloud properties. Here, results from several simulations of the effects of BC from fossil fuel and biofuel sources on global and regional climate and air pollution health are summarized. The simulations account for all the processes mentioned. Results are found to be statistically significant relative to chaotic variability in the climate system. Over time and in steady state, fossil-fuel soot plus biofuel soot are found to enhance warming more than methane. The sum of the soots causes less steady-state warming but more short term warming than does carbon dioxide. Thus eliminating soot emissions from both sources may be the fastest method of reducing rapid climate warming and possibly the only method of saving the Arctic ice. Eliminating such emissions may also reduce over 1.5 million deaths worldwide, particularly in developing countries. Short term mitigation options include the targeting of fossil-fuel and biofuel BC sources with particle traps, new stove technologies, and rural

  9. Relation Between the Adsorbed Quantity and the Immersion Enthalpy in Catechol Aqueous Solutions on Activated Carbons

    PubMed Central

    Moreno-Piraján, Juan Carlos; Blanco, Diego; Giraldo, Liliana

    2012-01-01

    An activated carbon, CarbochemTM—PS230, was modified by chemical and thermal treatment in flow of H2, in order to evaluate the influence of the activated carbon chemical characteristics in the adsorption of the catechol. The catechol adsorption in aqueous solution was studied along with the effect of the pH solution in the adsorption process of modified activated carbons and the variation of immersion enthalpy of activated carbons in the aqueous solutions of catechol. The interaction solid-solution is characterized by adsorption isotherms analysis, at 298 K and pH 7, 9 and 11 in order to evaluate the adsorption value above and below that of the catechol pKa. The adsorption capacity of carbons increases when the solution pH decreases. The retained amount increases slightly in the reduced carbon to maximum adsorption pH and diminishes in the oxidized carbon. Similar conclusions are obtained from the immersion enthalpies, whose values increase with the solute quantity retained. In granular activated carbon (CAG), the immersion enthalpies obtained are between 21.5 and 45.7 J·g−1 for catechol aqueous solutions in a range of 20 at 1500 mg·L−1. PMID:22312237

  10. Fluorinated alcohols as promoters for the metal-free direct substitution reaction of allylic alcohols with nitrogenated, silylated, and carbon nucleophiles.

    PubMed

    Trillo, Paz; Baeza, Alejandro; Nájera, Carmen

    2012-09-01

    The direct allylic substitution reaction using allylic alcohols in 1,1,1,3,3,3-hexafluoroisopropanol (HFIP) and 2,2,2-trifluoroethanol (TFE) as reaction media is described. The developed procedure is simple, works under mild conditions (rt, 50 and 70 °C), and proves to be very general, since different nitrogenated nucleophiles and carbon nucleophiles can be used achieving high yields, especially when HFIP is employed as solvent and aromatic allylic alcohols are the substrates. Thus, sulfonamides, carbamates, carboxamides, and amines can be successfully employed as nitrogen-based nucleophiles. Likewise, silylated nucleophiles such as trimethylsilylazide, allyltrimethylsilane, trimethylsilane, and trimethylsilylphenylacetylene give the corresponding allylic substitution products in high yields. Good results for the Friedel-Crafts adducts are also achieved with aromatic compounds (phenol, anisole, indole, and anilines) as nucleophiles. Particularly interesting are the results obtained with electron-rich anilines, which can behave as nitrogenated or carbon nucleophiles depending on their electronic properties and the solvent employed. In addition, 1,3-dicarbonyl compounds (acetylacetone and Meldrum's acid) are also successfully employed as soft carbon nucleophiles. Studies for mechanism elucidation are also reported, pointing toward the existence of carbocationic intermediates and two working reaction pathways for the obtention of the allylic substitution product.

  11. Hydrothermal Carbonization: a feasible solution to convert biomass to soil?

    NASA Astrophysics Data System (ADS)

    Tesch, Walter; Tesch, Petra; Pfeifer, Christoph

    2013-04-01

    The erosion of fertile soil is a severe problem arising right after peak oil (Myers 1996). That this issue is not only a problem of arid countries is shown by the fact that even the European Commission defined certain milestones to address the problem of soil erosion in Europe (European Commission 2011). The application of bio-char produced by torrefaction or pyrolysis for the remediation, revegetation and restoration of depleted soils started to gain momentum recently (Rillig 2010, Lehmann 2011, Beesley 2011). Hydrothermal carbonization (HTC) is a promising thermo-chemical process that can be applied to convert organic feedstock into fertile soil and water, two resources which are of high value in regions being vulnerable to erosion. The great advantage of HTC is that organic feedstock (e.g. organic waste) can be used without any special pretreatment (e.g. drying) and so far no restrictions have been found regarding the composition of the organic matter. By applying HTC the organic material is processed along a defined pathway in the Van Krevelen plot (Behrendt 2006). By stopping the process at an early stage a nutritious rich material can be obtained, which is known to be similar to terra preta. Considering that HTC-coal is rich in functional groups and can be derived from the process under "wet" conditions, it can be expected that it shall allow soil bacteria to settle more easily compared to the bio-char derived by torrefaction or pyrolysis. In addition, up to 10 tons process water per ton organic waste can be gained (Vorlop 2009). Thus, as organic waste, loss of fertile soil and water scarcity becomes a serious issue within the European Union, hydrothermal carbonization can provide a feasible solution to address these issues of our near future. The presentation reviews the different types of feedstock investigated for the HTC-Process so far and gives an overview on the current stage of development of this technology. References Beesley L., Moreno-Jiménez E

  12. Fabrication and characterization of hybrid nanofibers from poly(vinyl alcohol), milk protein and metal carbonates.

    PubMed

    Mahanta, Narahari; Teow, Yiwei; Valiyaveettil, Suresh

    2012-08-01

    Porous three dimensional nanofibrous membranes were fabricated from poly(vinyl alcohol) (PVA), milk protein and inorganic salts such as calcium carbonate (CaCO3) or magnesium carbonate (MgCO3). Microscopic investigations showed that the fibers have smooth morphology with an average diameter of 300-500 nm and a surface area of 5.29 m2g(-1). Thermal analysis of the composite nanofibers showed a decrease in glass transition temperature as compared to PVA nanofiber. Incorporation of CaCO3 and MgCO3 into the nanofiber matrix was confirmed by energy dispersive spectroscopy and X-ray diffraction analysis. The cytocompatibility of electrospun composite nanofiber sheets was evaluated using human lung fibroblasts (IMR-90). There was an increase in cell attachment and cell density on milk protein incorporated to PVA-CaCO3 and PVA-MgCO3 fibers within a week of cell seeding. The cytocompatibility and increase in cell adhesion property of the hybrid nanofiber may provide significant advantages for such materials in biomedical applications. PMID:22962721

  13. Comparison of Chain Conformation of Poly(vinyl alcohol) in Solutions and Melts from Quantum Chemistry Based Molecular Dynamics Simulations

    NASA Technical Reports Server (NTRS)

    Jaffe, Richard; Han, Jie; Matsuda, Tsunetoshi; Yoon, Do; Langhoff, Stephen R. (Technical Monitor)

    1997-01-01

    Confirmations of 2,4-dihydroxypentane (DHP), a model molecule for poly(vinyl alcohol), have been studied by quantum chemistry (QC) calculations and molecular dynamics (MD) simulations. QC calculations at the 6-311G MP2 level show the meso tt conformer to be lowest in energy followed by the racemic tg, due to intramolecular hydrogen bond between the hydroxy groups. The Dreiding force field has been modified to reproduce the QC conformer energies for DHP. MD simulations using this force field have been carried out for DHP molecules in the gas phase, melt, and CHCl3 and water solutions. Extensive intramolecular hydrogen bonding is observed for the gas phase and CHCl3 solution, but not for the melt or aqueous solution, Such a condensed phase effect due to intermolecular interactions results in a drastic change in chain conformations, in agreement with experiments.

  14. Polyvinyl alcohol gelation: A structural locking-up agent and carbon source for Si/CNT/C composites as high energy lithium ion battery anode

    NASA Astrophysics Data System (ADS)

    Chen, Dingqiong; Liao, Wenjuan; Yang, Yang; Zhao, Jinbao

    2016-05-01

    A novel polyvinyl alcohol (PVA) hydrogel method is developed to synthesize Si/CNT/C composites. The Si nanoparticles and CNTs are 'position' locked up by PVA hydrogel in a simple aqueous solution process, and then the Si-CNT-PVA hydrogel has pyrolyzed to form Si/CNT/C composites. In this unique structured Si/CNT/C composites, the CNTs form a porous network acting both as conductive agent for electron transfer and buffer space to accommodate huge Si volume change during lithiation/delithiation process, while the coating layer of carbon carbonized from polyvinyl alcohol (PVA) hydrogel is conducive to stabilize the interweaved composite structure. The complex structures of Si/CNT/C composites and their electrochemical properties are presented in this paper. The Si/CNT/C composites exhibit an initial reversible capacity of nearly 800 mAhg-1, an excellent capacity retention of 97.1% after 100 cycles at the rate of 0.1 C, and high capacity retention even at high current rate.

  15. Oxidative Mineralization and Characterization of Polyvinyl Alcohol Solutions for Wastewater Treatment

    SciTech Connect

    Oji, L.N.

    1999-08-31

    The principal objectives of this study are to identify an appropriate polyvinyl alcohol (PVA) oxidative mineralization technique, perform compatibility and evaporation fate tests for neat and mineralized PVA, and determine potential for PVA chemical interferences which may affect ion exchange utilization for radioactive wastewater processing in the nuclear industry.

  16. Fetal Alcohol Syndrome: Understanding the Problem; Understanding the Solution; What Indian Communities Can Do.

    ERIC Educational Resources Information Center

    Streissguth, Ann P.

    1994-01-01

    Summarizes facts about fetal alcohol syndrome (FAS), including physical and mental symptoms; cause; prevalence overall and in Indian communities; and problems of infants, children, and adults with FAS. Emphasizes the importance of public awareness, professional education, and provision of community services to prevent FAS. Outlines specific…

  17. CO2 adsorption properties of char produced from brown coal impregnated with alcohol amine solutions.

    PubMed

    Baran, Paweł; Zarębska, Katarzyna; Czuma, Natalia

    2016-07-01

    Carbon dioxide (CO2) emission reduction is critical to mitigating climate change. Power plants for heating and industry are significant sources of CO2 emissions. There is a need for identifying and developing new, efficient methods to reduce CO2 emissions. One of the methods used is flue gas purification by CO2 capture through adsorption. This study aimed to develop CO2 adsorbent out of modified brown coal impregnated with solutions of first-, second-, and third-order amines. Low-temperature nitrogen adsorption isotherms and CO2 isotherms were measured for the prepared samples. The results of experiments unexpectedly revealed that CO2 sorption capacity decreased after impregnation. Due to lack of strait trends in CO2 sorption capacity decrease, the results were closely analyzed to find the reason for the inconsistencies. It was revealed that different amines represent different affinities for CO2 and that the size and structure of impregnating factor has influence on the CO2 sorption capacity of impregnated material. The character of a support was also noticeable as well for impregnation results as for the affinity to CO2. The influence of amine concentration used was investigated along with the comparison on how the theoretical percentage of the impregnation on the support influenced the results. The reaction mechanism of tertiary amine was taken into consideration in connection to no presence of water vapor during the experiments. Key findings were described in the work and provide a strong basis for further studies on CO2 adsorption on amine-impregnated support. PMID:27317051

  18. Fabrication and processing of high-strength densely packed carbon nanotube yarns without solution processes.

    PubMed

    Liu, Kai; Zhu, Feng; Liu, Liang; Sun, Yinghui; Fan, Shoushan; Jiang, Kaili

    2012-06-01

    Defects of carbon nanotubes, weak tube-tube interactions, and weak carbon nanotube joints are bottlenecks for obtaining high-strength carbon nanotube yarns. Some solution processes are usually required to overcome these drawbacks. Here we fabricate ultra-long and densely packed pure carbon nanotube yarns by a two-rotator twisting setup with the aid of some tensioning rods. The densely packed structure enhances the tube-tube interactions, thus making high tensile strengths of carbon nanotube yarns up to 1.6 GPa. We further use a sweeping laser to thermally treat as-produced yarns for recovering defects of carbon nanotubes and possibly welding carbon nanotube joints, which improves their Young's modulus by up to ∼70%. The spinning and laser sweeping processes are solution-free and capable of being assembled together to produce high-strength yarns continuously as desired. PMID:22538869

  19. Fabrication and processing of high-strength densely packed carbon nanotube yarns without solution processes

    NASA Astrophysics Data System (ADS)

    Liu, Kai; Zhu, Feng; Liu, Liang; Sun, Yinghui; Fan, Shoushan; Jiang, Kaili

    2012-05-01

    Defects of carbon nanotubes, weak tube-tube interactions, and weak carbon nanotube joints are bottlenecks for obtaining high-strength carbon nanotube yarns. Some solution processes are usually required to overcome these drawbacks. Here we fabricate ultra-long and densely packed pure carbon nanotube yarns by a two-rotator twisting setup with the aid of some tensioning rods. The densely packed structure enhances the tube-tube interactions, thus making high tensile strengths of carbon nanotube yarns up to 1.6 GPa. We further use a sweeping laser to thermally treat as-produced yarns for recovering defects of carbon nanotubes and possibly welding carbon nanotube joints, which improves their Young's modulus by up to ~70%. The spinning and laser sweeping processes are solution-free and capable of being assembled together to produce high-strength yarns continuously as desired.

  20. THE SOLAR NEBULA ON FIRE: A SOLUTION TO THE CARBON DEFICIT IN THE INNER SOLAR SYSTEM

    SciTech Connect

    Lee, Jeong-Eun; Bergin, Edwin A.; Nomura, Hideko E-mail: ebergin@umich.edu

    2010-02-10

    Despite a surface dominated by carbon-based life, the bulk composition of the Earth is dramatically carbon poor when compared to the material available at formation. Bulk carbon deficiency extends into the asteroid belt representing a fossil record of the conditions under which planets are born. The initial steps of planet formation involve the growth of primitive sub-micron silicate and carbon grains in the Solar Nebula. We present a solution wherein primordial carbon grains are preferentially destroyed by oxygen atoms ignited by heating due to stellar accretion at radii <5 AU. This solution can account for the bulk carbon deficiency in the Earth and meteorites, the compositional gradient within the asteroid belt, and for growing evidence for similar carbon deficiency in rocks surrounding other stars.

  1. [Determination of low-carbon alcohols, aldehydes and ketones in aqueous products of Fischer-Tropsch synthesis by gas chromatography].

    PubMed

    Gai, Qingqing; Wu, Peng; Shi, Yulin; Bai, Yu; Long, Yinhua

    2015-01-01

    A method for the determination of low-carbon (C1-C8) alcohols, aldehydes and ketones in aqueous products of Fischer-Tropsch synthesis was developed by gas chromatography. It included the optimization of separation conditions, the precision and accuracy of determination, and the use of correction factors of the analytes to ethanol for quantification. The aqueous products showed that the correlation coefficients for ethanol in different content ranges were above 0.99, which means it had good linear correlations. The spiked recoveries in the aqueous samples of Fischer-Tropsch synthesis were from 93.4% to 109.6%. The accuracy of the method can satisfy the requirement for the analysis of the aqueous samples of Fischer-Tropsch synthesis. The results showed that the total mass fractions of the major low-carbon alcohols, aldehydes, ketones in aqueous products of Fischer-Tropsch synthesis were about 3%-12%, and the contents of ethanol were the highest (about 1.7%-7.3%). The largest share of the total proportion was n-alcohols, followed by isomeric alcohols, aldehydes and ketones were the lowest. This method is simple, fast, and has great significance for the analysis of important components in aqueous products of Fischer-Tropsch synthesis.

  2. Enthalpy pair coefficients of interaction for DL-valine in aqueous solutions of polyatomic alcohols at 298 K

    NASA Astrophysics Data System (ADS)

    Mezhevoi, I. N.; Badelin, V. G.

    2013-12-01

    Integral enthalpies of dissolution Δsol H m of DL-valine are measured via calorimetry of dissolution in aqueous solutions of glycerol, ethylene glycol, and 1,2-propylene glycol. Standard values of the enthalpies of dissolution (Δsol H ○) and transfer (Δtr H ○) of amino acid from water to mixed solvent are calculated from the resulting experimental data. The enthalpy coefficients for pair interactions hxy of amino acid with polyatomic alcohol molecules are calculated using the McMillan-Meyer theory and have positive values. The obtained results are discussed in light of the theory of the predomination of various types of interactions in mixed solutions and the effect of structural features of interacting biomolecules on the thermochemical parameters of the dissolution of amino acids.

  3. Conversion of C2-C4 alcohols over copper-containing catalysts on carbon and fluorocarbon fibers

    NASA Astrophysics Data System (ADS)

    Tveritinova, E. A.; Zhitnev, Yu. N.; Roshchina, T. M.; Lunin, V. V.

    2011-07-01

    Carbon and fluorocarbon fibers were used as carriers for the preparation of copper catalysts from copper oxalate as precursor. The catalytic properties of catalyst were studied in the reaction of the dehydrogenation of C2-C4 alcohols by the pulsed microcatalytic method. The effect of the copper content in the catalyst, the reaction temperature on the degree of conversion, and the relation of the reaction channels were studied. The electron microphotographs were obtained, specific surfaces were measured, and X-ray pictures and infrared spectra of catalysts were taken. The activity of the catalysts on the carbon and fluorocarbon fibers in the dehydration-dehydrogenation reactions of C2-C4 alcohols was comparatively estimated. It was shown that the selectivity of the products from the dehydrogenation reaction is higher for the Cu-fluorocarbon fiber catalyst.

  4. Extraction of palladium from acidic solutions with the use of carbon adsorbents

    SciTech Connect

    O.N. Kononova; N.G. Goryaeva; N.B. Dostovalova; S.V. Kachin; A.G. Kholmogorov

    2007-08-15

    We studied the sorption of palladium(II) on LKAU-4, LKAU-7, and BAU carbon adsorbents from model hydrochloric acid solutions and the solutions of spent palladium-containing catalysts. It was found that sorbents based on charcoal (BAU) and anthracite (LKAU-4) were characterized by high sorption capacities for palladium. The kinetics of the saturation of carbon adsorbents with palladium(II) ions was studied, and it was found that more than 60% of the initial amount of Pd(II) was recovered in a 1-h contact of an adsorbent with a model solution. This value for the solutions of spent catalysts was higher than 35%.

  5. The impedance characterization of Carbon Nanotubes - Fumed Silica Poly (vinyl alcohol) Composites

    NASA Astrophysics Data System (ADS)

    Othman, R. N.; Wilkinson, A. N.

    2016-06-01

    Carbon Nanotube (CNT) was grown on the surface of fumed silica via chemical vapor deposition (CVD) method. In this work, silica acted as a site that holds CNT together, which prevents further agglomeration during composite processing. Iron catalyst at different loading (7.5 wt. % up to 25 wt. %) was introduced via impregnation method to synthesize CNT at 1000°C, under methane flow. Floating catalyst method was used where ferrocene (2.5 wt. % and 5 wt. %) was used as starting reactants together with toluene at 760°C. The reaction time was set at 1 hour for both methods. It was later confirmed via SEM images that the floating catalyst method is more suitable to produce a large amount of CNTs. The sample synthesized via floating catalyst method at both 2.5 wt.% and 5 wt. % ferrocene was later used to prepare composites. Composite films of the particles in poly (vinyl alcohol) (PVOH) were cast and their TEM images show that the dispersion is indeed uniform. From impedance measurement, it was found that the particles synthesized via floating catalyst method were found to form an electrically-conductive percolated network with percolation threshold of 1 wt. %, obtained via percolation equation.

  6. Electrospun polyvinyl alcohol/carbon dioxide modified polyethyleneimine composite nanofiber scaffolds.

    PubMed

    Wu, Han-Bing; Bremner, David H; Nie, Hua-Li; Quan, Jing; Zhu, Li-Min

    2015-05-01

    A novel biocompatible polyvinyl alcohol/carbon dioxide modified polyethyleneimine (PVA/PEI-CO2) composite nanofiber was fabricated by a green and facile protocol, which reduces the cytotoxicity of PEI through the surface modification of the PEI with CO2. The (13)C NMR spectrum, elemental analysis, and TGA show that CO2 has been incorporated in the PEI surface resulting in a relatively stable structure. The resulting PVA/PEI-CO2 composite nanofibers have been characterized by attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), contact angle, and scanning electron microscopy (SEM). The results show that the average diameters of the nanofibers range from 265 ± 53 nm to 423 ± 80 nm. The cytotoxicity of PVA/PEI-CO2 composite nanofibers was assessed by cytotoxicity evaluation using the growth and cell proliferation of normal mice Schwann cells. SEM and the MTT assay demonstrated the promotion of cell growth and proliferation on the PVA/PEI-CO2 composite scaffold. It suggests that PEI-CO2 can have tremendous potential applications in biological material research. PMID:25540321

  7. Anomalous electrical transport properties of polyvinyl alcohol-multiwall carbon nanotubes composites below room temperature

    NASA Astrophysics Data System (ADS)

    Chakraborty, G.; Gupta, K.; Meikap, A. K.; Babu, R.; Blau, W. J.

    2011-02-01

    The dc and ac electrical transport property of polyvinyl alcohol-multiwall carbon nanotubes composites has been investigated within a temperature range 77≤T≤300 K and in the frequency range 20 Hz-1 MHz in presence as well as in absence of a transverse magnetic field up to 1 T. The dc conductivity follows variable range hopping model. The magnetoconductivity of the samples changes a sign from positive to negative with an increase in temperature which can be interpreted by the dominancy of the quantum interference effect over the wave function shrinkage effect. The ac conductivity follows a power law whereas the temperature dependence of frequency exponent s can be explained by correlated barrier hopping model. The dielectric behavior of the samples has been governed by the grain and grain boundary resistance and capacitance. The ac conductivity reduces with the application of magnetic field. Although the theoretical model to explain it, is still lacking, we may conclude that this is due to the increase in grain and grain boundary resistance by the application of magnetic field.

  8. Multiwall carbon nanotube polyvinyl alcohol-based saturable absorber in passively Q-switched fiber laser.

    PubMed

    Ahmad, H; Ismail, M F; Hassan, S N M; Ahmad, F; Zulkifli, M Z; Harun, S W

    2014-10-20

    In this work, we demonstrated a compact Q-switched erbium-doped fiber laser capable of generating high-energy pulses using a newly developed multiwall carbon nanotube (CNT) polyvinyl alcohol (PVA) thin film based saturable absorber. Q-switched pulse operation is obtained by sandwiching the thin film between two fiber ferrules forming a saturable absorber. A saturable absorber with 1.25 wt. % of PVA concentration shows a consistency in generating pulsed laser with a good range of tunable repetition rate, shortest pulse width, and produces a high pulse energy and peak power. The pulse train generated has a maximum repetition rate of 29.9 kHz with a corresponding pulse width of 3.49 μs as a function of maximum pump power of 32.15 mW. The maximum average output power of the Q-switched fiber laser system is 1.49 mW, which translates to a pulse energy of 49.8 nJ. The proposed method of multiwall CNT/PVA thin film fabrication is low in cost and involves uncomplicated processes. PMID:25402790

  9. Rapid analysis of phthalates in beverage and alcoholic samples by multi-walled carbon nanotubes/silica reinforced hollow fibre-solid phase microextraction.

    PubMed

    Li, Jia; Su, Qiong; Li, Ke-Yao; Sun, Chu-Feng; Zhang, Wen-Bo

    2013-12-15

    A novel procedure based on multi-walled carbon nanotubes (MWCNTs)/silica reinforced hollow fibre solid-phase microextraction combined with gas chromatography-mass spectrometry has been developed to analyse trace phthalate acid esters in beverage and alcoholic samples. Because of their excellent adsorption capability towards hydrophobic compounds, functionalized MWCNTs, acting as solid-phase sorbent, were co-deposited with silica particles in the pores of polypropylene hollow fibre through a layer-by-layer self-assembly technique. The parameters influencing the extraction efficiency, such as pH values and ionic strength of sample solution, extraction time, temperature and desorption solvent were optimised. Recoveries for phthalates at spiking levels in different matrices were satisfactory (between 68% and 115%). Moreover, the results were further confirmed by comparing them with those obtained using a solvent extraction method according to the national standard of China.

  10. PROCESS FOR RECOVERY OF URANIUM AND VANADIUM FROM CARBONATE SOLUTIONS BY REDUCTION-PRECIPITATION

    DOEpatents

    Ellis, D.A.; Lindblom, R.O.

    1957-09-24

    A process employing carbonate leaching of ores and an advantageous methcd of recovering the uranium and vanadium from the leach solution is described. The uranium and vanadium can be precipitated from carbonate leach solutions by reaction with sodium amalgam leaving the leach solution in such a condition that it is economical to replenish for recycling. Such a carbonate leach solution is treated with a dilute sodium amalgam having a sodium concentration within a range of about 0.01 to 0.5% of sodium. Efficiency of the treatment is dependent on at least three additional factors, intimacy of contact of the amalgam with the leach solution, rate of addition of the amalgam and exclusion of oxygen (air).

  11. Simple Method for Simultaneous Determination of Carbonate, Sulfite and Hydroxide in Solution

    NASA Astrophysics Data System (ADS)

    Al-Itawi, Hossam I.; Al-Ebaisat, Hamdan; Al-Garaleh, Mazen

    A method is proposed for the simultaneous determination of carbon dioxide and sulphur dioxide in a complex matrices. The method involves salvation of the tow gases in Sodium Hydroxide solution followed by simultaneous determination of the three species (carbonate, sulfite and hydroxide) using conductometric and potentiometric titration. What set this method apart from other determination methods it`s simplicity.

  12. Inhibitive effects of palm kernel oil on carbon steel corrosion by alkaline solution

    NASA Astrophysics Data System (ADS)

    Zulkafli, M. Y.; Othman, N. K.; Lazim, A. M.; Jalar, A.

    2013-11-01

    The behavior of carbon steel SAE 1045 in 1 M NaOH solution containing different concentrations of palm kernel oil (PKO) has been studied by weight loss and polarization measurement. Results showed that the corrosion of carbon steel in NaOH solution was considerably reduced in presence of such inhibitors. The inhibition efficiency increases when concentration of inhibitor increase. Maximum inhibition efficiency (≈ 96.67%) is obtained at PKO concentration 8 v/v %. This result revealed that palm kernel oil can act as a corrosion inhibitor in an alkaline medium. Corrosion rates of carbon steel decrease as the concentration of inhibitor is increased.

  13. Effect of retained austenite and solute carbon on the mechanical properties in TRIP steels

    NASA Astrophysics Data System (ADS)

    Seong, B. S.; Shin, E. J.; Han, Y. S.; Lee, C. H.; Kim, Y. J.; Kim, S. J.

    2004-07-01

    The mechanical properties of transformation induced plasticity (TRIP) steels are strongly affected by the amount of retained austenite and the solute carbon in austenite. In this study, the Rietveld method using neutron diffraction patterns was introduced for determining the weight fraction of retained austenite and the solute carbon content. C-Si-Mn TRIP steels with different austempering temperatures were used. The retained austenite and the carbon content in the austenite of these steel sheets were quantitatively analyzed by neutron diffractions, and their effects on the mechanical properties of the steels were evaluated.

  14. Basic solutions to carbon/carbon oxidation: Science and technology. Annual technical report, 15 April 1993-14 April 1994

    SciTech Connect

    Harrison, T.R.; Chung, T.; Radovic, L.; Pantano, C.; Thrower, P.A.

    1994-05-13

    The attached report addresses the first year of a program aimed at developing basic solutions to carbon/carbon composite oxidation. In particular, one primary thrust is the development of boron containing carbons through pyrolysis of boron containing polymers. Additionally, a basic understanding of the oxidation mechanisms in carbons and boron containing carbons is being sought. Several new boron containing precursors have been synthesized, which can be converted to B/C materials after pyrolysis. In particular, polyacrylonitrile (PAN) has been copolymerized with a boron-containing monomer (vinylcatecholborane.) Approximately 68% of the original boron is retained after pyrolysis yielding a product with 3.4% boron. 1,4-polybutadiene (PBD) has been hydroborated to contain large amounts of boron. Model compounds have been used to prepare polydiyne with considerable amounts of boron. In the latter two cases, direct analysis for % boron is not yet available. Preliminary TGA data suggests that PBD containing boron results in a more stable structure.

  15. Solution-based carbohydrate synthesis of individual solid, hollow, and porous carbon nanospheres using spray pyrolysis.

    PubMed

    Wang, Chengwei; Wang, Yuan; Graser, Jake; Zhao, Ran; Gao, Fei; O'Connell, Michael J

    2013-12-23

    A facile and scalable solution-based, spray pyrolysis synthesis technique was used to synthesize individual carbon nanospheres with specific surface area (SSA) up to 1106 m(2)/g using a novel metal-salt catalyzed reaction. The carbon nanosphere diameters were tunable from 10 nm to several micrometers by varying the precursor concentrations. Solid, hollow, and porous carbon nanospheres were achieved by simply varying the ratio of catalyst and carbon source without using any templates. These hollow carbon nanospheres showed adsorption of to 300 mg of dye per gram of carbon, which is more than 15 times higher than that observed for conventional carbon black particles. When evaluated as supercapacitor electrode materials, specific capacitances of up to 112 F/g at a current density of 0.1 A/g were observed, with no capacitance loss after 20,000 cycles.

  16. Alkaline solution absorption of carbon dioxide method and apparatus

    DOEpatents

    Hobbs, D.T.

    1991-01-01

    Disclosed is a method for measuring the concentration of hydroxides (or pH) in alkaline solutions, using the tendency of hydroxides to adsorb CO{sub 2}. The method comprises passing CO{sub 2} over the surface of an alkaline solution in a remote tank before and after measurements of the CO{sub 2} concentration. Comparison of the measurements yields the adsorption fraction from which the hydroxide concentration can be calculated using a correlation of hydroxide or pH to adsorption fraction. A schematic is given of a process system according to a preferred embodiment of the invention. 2 figs.

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

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

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

  18. An Examination of Problems and Solutions Related to the Chronic "Revolving Door" Alcohol Abuser. DHSS Planning Guideline #1, Task Assignment #1.11. Long-Term Support, Chronic Alcoholism and Other Drug Abuse.

    ERIC Educational Resources Information Center

    Vick, John W.; Houden, Dorothy

    This report contains recommendations of a Wisconsin Task Assignment Steering Committee created to explore solutions to some significant problems facing adult chronic "revolving-detox-door" alcohol abusers (CRA's), persons with repeated admissions for detoxification services; and to examine the system that serves and funds them. This report is…

  19. Efficient organic solar cells with solution-processed carbon nanosheets as transparent electrodes

    NASA Astrophysics Data System (ADS)

    Na, Seok-In; Noh, Yong-Jin; Son, Su-Young; Kim, Tae-Wook; Kim, Seok-Soon; Lee, Sungho; Joh, Han-Ik

    2013-01-01

    We demonstrate that solution-processed carbon nanosheet (CNS) films can efficiently serve as transparent electrodes for organic solar cells (OSCs). The CNS was obtained by spin-coating of polyacrylonitrile (PAN) dissolved in dimethylformamide on quartz substrates, followed by stabilization and carbonization processes to convert polymer into CNS. The thickness of the newly developed CNS films was easily controlled by varying the PAN solution concentration. The polymer-converted CNS films were intensively examined for the feasibility of the use as transparent anodes in solar cells. This approach could be highly desirable for all-solution-processed or printed OSCs.

  20. Nitrogen and carbon removal efficiency of a polyvinyl alcohol gel based moving bed biofilm reactor system.

    PubMed

    Gani, Khalid Muzamil; Singh, Jasdeep; Singh, Nitin Kumar; Ali, Muntjeer; Rose, Vipin; Kazmi, A A

    2016-01-01

    In this study, the effectiveness of polyvinyl alcohol (PVA) gel beads in treating domestic wastewater was investigated: a moving bed biofilm reactor (MBBR) configuration (oxic-anoxic and oxic) with 10% filling fraction of biomass carriers was operated in a continuously fed regime at temperatures of 25, 20, 15 and 6 °C with hydraulic retention times (HRTs) of 32 h, 18 h, 12 h and 9 h, respectively. Influent loadings were in the range of 0.22-1.22 kg N m(-3) d(-1) (total nitrogen (TN)), 1.48-7.82 kg chemical oxygen demand (COD) m(-3) d(-1) (organic) and 0.12-0.89 kg NH4(+)-N m(-3)d(-1) (ammonia nitrogen). MBBR performance resulted in the maximum TN removal rate of 1.22 kg N m(-3) d(-1) when the temperature and HRT were 6 °C and 9 h, respectively. The carbon removal rate at this temperature and HRT was 6.82 kg COD m(-3) d(-1). Ammonium removal rates ranged from 0.13 to 0.75 kg NH4(+)-N m(-3) d(-1) during the study. Total phosphorus and suspended solid removal efficiency ranged from 84 to 98% and 85 to 94% at an influent concentration of 3.3-7.1 mg/L and 74-356 mg/L, respectively. The sludge wasted from the MBBR exhibited light weight features characterized by sludge volume index value of 185 mL/g. Experimental data obtained can be useful in further developing the concept of PVA gel based wastewater treatment systems.

  1. Nitrogen and carbon removal efficiency of a polyvinyl alcohol gel based moving bed biofilm reactor system.

    PubMed

    Gani, Khalid Muzamil; Singh, Jasdeep; Singh, Nitin Kumar; Ali, Muntjeer; Rose, Vipin; Kazmi, A A

    2016-01-01

    In this study, the effectiveness of polyvinyl alcohol (PVA) gel beads in treating domestic wastewater was investigated: a moving bed biofilm reactor (MBBR) configuration (oxic-anoxic and oxic) with 10% filling fraction of biomass carriers was operated in a continuously fed regime at temperatures of 25, 20, 15 and 6 °C with hydraulic retention times (HRTs) of 32 h, 18 h, 12 h and 9 h, respectively. Influent loadings were in the range of 0.22-1.22 kg N m(-3) d(-1) (total nitrogen (TN)), 1.48-7.82 kg chemical oxygen demand (COD) m(-3) d(-1) (organic) and 0.12-0.89 kg NH4(+)-N m(-3)d(-1) (ammonia nitrogen). MBBR performance resulted in the maximum TN removal rate of 1.22 kg N m(-3) d(-1) when the temperature and HRT were 6 °C and 9 h, respectively. The carbon removal rate at this temperature and HRT was 6.82 kg COD m(-3) d(-1). Ammonium removal rates ranged from 0.13 to 0.75 kg NH4(+)-N m(-3) d(-1) during the study. Total phosphorus and suspended solid removal efficiency ranged from 84 to 98% and 85 to 94% at an influent concentration of 3.3-7.1 mg/L and 74-356 mg/L, respectively. The sludge wasted from the MBBR exhibited light weight features characterized by sludge volume index value of 185 mL/g. Experimental data obtained can be useful in further developing the concept of PVA gel based wastewater treatment systems. PMID:27054722

  2. Adsorption of various alcohols on Illinois No. 6 coal in aqueous solutions

    SciTech Connect

    Kwon, K.C.; Rigby, R.R.

    1993-07-01

    Hydrophilicity, hydrophobicity and aromacity of Illinois {number_sign}6 coal in water are relatively determined by evaluating equilibrium physical/chemical adsorption of probe compounds on the coal. Experiments on equilibrium adsorption loadings of various additives on 60--200 mesh Illinois {number_sign}6 coal (DECS-2; Randolph county) were performed to investigate relatively surface properties of the coal at 25{degree}C. The additives include various alcohols, alkanes and aromatic compounds. The main objectives of this research are to evaluate relatively surface properties of raw coals, treated coals and coal minerals with the inverse liquid chromatography technique, using various probe compounds, to analyze flotation recoveries of coals with a micro-flotation apparatus in order to relate coal floatability to evaluated coal surface properties, and to delineate roles of coal-cleaning/handling additives with the inverse liquid chromatography technique.

  3. Pediatric non-alcoholic fatty liver disease: Recent solutions, unresolved issues, and future research directions.

    PubMed

    Clemente, Maria Grazia; Mandato, Claudia; Poeta, Marco; Vajro, Pietro

    2016-09-28

    Non-alcoholic fatty liver disease (NAFLD) in children is becoming a major health concern. A "multiple-hit" pathogenetic model has been suggested to explain the progressive liver damage that occurs among children with NAFLD. In addition to the accumulation of fat in the liver, insulin resistance (IR) and oxidative stress due to genetic/epigenetic background, unfavorable lifestyles, gut microbiota and gut-liver axis dysfunction, and perturbations of trace element homeostasis have been shown to be critical for disease progression and the development of more severe inflammatory and fibrotic stages [non-alcoholic steatohepatitis (NASH)]. Simple clinical and laboratory parameters, such as age, history, anthropometrical data (BMI and waist circumference percentiles), blood pressure, surrogate clinical markers of IR (acanthosis nigricans), abdominal ultrasounds, and serum transaminases, lipids and glucose/insulin profiles, allow a clinician to identify children with obesity and obesity-related conditions, including NAFLD and cardiovascular and metabolic risks. A liver biopsy (the "imperfect" gold standard) is required for a definitive NAFLD/NASH diagnosis, particularly to exclude other treatable conditions or when advanced liver disease is expected on clinical and laboratory grounds and preferably prior to any controlled trial of pharmacological/surgical treatments. However, a biopsy clearly cannot represent a screening procedure. Advancements in diagnostic serum and imaging tools, especially for the non-invasive differentiation between NAFLD and NASH, have shown promising results, e.g., magnetic resonance elastography. Weight loss and physical activity should be the first option of intervention. Effective pharmacological treatments are still under development; however, drugs targeting IR, oxidative stress, proinflammatory pathways, dyslipidemia, gut microbiota and gut liver axis dysfunction are an option for patients who are unable to comply with the recommended lifestyle

  4. Pediatric non-alcoholic fatty liver disease: Recent solutions, unresolved issues, and future research directions

    PubMed Central

    Clemente, Maria Grazia; Mandato, Claudia; Poeta, Marco; Vajro, Pietro

    2016-01-01

    Non-alcoholic fatty liver disease (NAFLD) in children is becoming a major health concern. A “multiple-hit” pathogenetic model has been suggested to explain the progressive liver damage that occurs among children with NAFLD. In addition to the accumulation of fat in the liver, insulin resistance (IR) and oxidative stress due to genetic/epigenetic background, unfavorable lifestyles, gut microbiota and gut-liver axis dysfunction, and perturbations of trace element homeostasis have been shown to be critical for disease progression and the development of more severe inflammatory and fibrotic stages [non-alcoholic steatohepatitis (NASH)]. Simple clinical and laboratory parameters, such as age, history, anthropometrical data (BMI and waist circumference percentiles), blood pressure, surrogate clinical markers of IR (acanthosis nigricans), abdominal ultrasounds, and serum transaminases, lipids and glucose/insulin profiles, allow a clinician to identify children with obesity and obesity-related conditions, including NAFLD and cardiovascular and metabolic risks. A liver biopsy (the “imperfect” gold standard) is required for a definitive NAFLD/NASH diagnosis, particularly to exclude other treatable conditions or when advanced liver disease is expected on clinical and laboratory grounds and preferably prior to any controlled trial of pharmacological/surgical treatments. However, a biopsy clearly cannot represent a screening procedure. Advancements in diagnostic serum and imaging tools, especially for the non-invasive differentiation between NAFLD and NASH, have shown promising results, e.g., magnetic resonance elastography. Weight loss and physical activity should be the first option of intervention. Effective pharmacological treatments are still under development; however, drugs targeting IR, oxidative stress, proinflammatory pathways, dyslipidemia, gut microbiota and gut liver axis dysfunction are an option for patients who are unable to comply with the recommended

  5. Pediatric non-alcoholic fatty liver disease: Recent solutions, unresolved issues, and future research directions.

    PubMed

    Clemente, Maria Grazia; Mandato, Claudia; Poeta, Marco; Vajro, Pietro

    2016-09-28

    Non-alcoholic fatty liver disease (NAFLD) in children is becoming a major health concern. A "multiple-hit" pathogenetic model has been suggested to explain the progressive liver damage that occurs among children with NAFLD. In addition to the accumulation of fat in the liver, insulin resistance (IR) and oxidative stress due to genetic/epigenetic background, unfavorable lifestyles, gut microbiota and gut-liver axis dysfunction, and perturbations of trace element homeostasis have been shown to be critical for disease progression and the development of more severe inflammatory and fibrotic stages [non-alcoholic steatohepatitis (NASH)]. Simple clinical and laboratory parameters, such as age, history, anthropometrical data (BMI and waist circumference percentiles), blood pressure, surrogate clinical markers of IR (acanthosis nigricans), abdominal ultrasounds, and serum transaminases, lipids and glucose/insulin profiles, allow a clinician to identify children with obesity and obesity-related conditions, including NAFLD and cardiovascular and metabolic risks. A liver biopsy (the "imperfect" gold standard) is required for a definitive NAFLD/NASH diagnosis, particularly to exclude other treatable conditions or when advanced liver disease is expected on clinical and laboratory grounds and preferably prior to any controlled trial of pharmacological/surgical treatments. However, a biopsy clearly cannot represent a screening procedure. Advancements in diagnostic serum and imaging tools, especially for the non-invasive differentiation between NAFLD and NASH, have shown promising results, e.g., magnetic resonance elastography. Weight loss and physical activity should be the first option of intervention. Effective pharmacological treatments are still under development; however, drugs targeting IR, oxidative stress, proinflammatory pathways, dyslipidemia, gut microbiota and gut liver axis dysfunction are an option for patients who are unable to comply with the recommended lifestyle

  6. Pediatric non-alcoholic fatty liver disease: Recent solutions, unresolved issues, and future research directions

    PubMed Central

    Clemente, Maria Grazia; Mandato, Claudia; Poeta, Marco; Vajro, Pietro

    2016-01-01

    Non-alcoholic fatty liver disease (NAFLD) in children is becoming a major health concern. A “multiple-hit” pathogenetic model has been suggested to explain the progressive liver damage that occurs among children with NAFLD. In addition to the accumulation of fat in the liver, insulin resistance (IR) and oxidative stress due to genetic/epigenetic background, unfavorable lifestyles, gut microbiota and gut-liver axis dysfunction, and perturbations of trace element homeostasis have been shown to be critical for disease progression and the development of more severe inflammatory and fibrotic stages [non-alcoholic steatohepatitis (NASH)]. Simple clinical and laboratory parameters, such as age, history, anthropometrical data (BMI and waist circumference percentiles), blood pressure, surrogate clinical markers of IR (acanthosis nigricans), abdominal ultrasounds, and serum transaminases, lipids and glucose/insulin profiles, allow a clinician to identify children with obesity and obesity-related conditions, including NAFLD and cardiovascular and metabolic risks. A liver biopsy (the “imperfect” gold standard) is required for a definitive NAFLD/NASH diagnosis, particularly to exclude other treatable conditions or when advanced liver disease is expected on clinical and laboratory grounds and preferably prior to any controlled trial of pharmacological/surgical treatments. However, a biopsy clearly cannot represent a screening procedure. Advancements in diagnostic serum and imaging tools, especially for the non-invasive differentiation between NAFLD and NASH, have shown promising results, e.g., magnetic resonance elastography. Weight loss and physical activity should be the first option of intervention. Effective pharmacological treatments are still under development; however, drugs targeting IR, oxidative stress, proinflammatory pathways, dyslipidemia, gut microbiota and gut liver axis dysfunction are an option for patients who are unable to comply with the recommended

  7. Fabrication of carbon nanowires by pyrolysis of aqueous solution of sugar within asbestos nanofibers

    NASA Astrophysics Data System (ADS)

    Butko, V. Yu.; Fokin, A. V.; Nevedomskii, V. N.; Kumzerov, Yu. A.

    2015-05-01

    Carbon nanowires have been fabricated by pyrolysis of an aqueous solution of sugar in nanochannels of asbestos fibers. Electron microscopy demonstrates that the diameter of these nanochannels corresponds to the diameter of the thinnest of the carbon nanowires obtained. Some of these nanowires have a graphite crystal lattice and internal pores. After asbestos is etched out, the carbon nanowires can retain the original shape of the asbestos fibers. Heating in an inert atmosphere reduces the electrical resistivity of the carbon nanowires to ˜0.035 Ω cm.

  8. CIS(CIGS) thin films prepared for solar cells by one-step electrodeposition in alcohol solution

    NASA Astrophysics Data System (ADS)

    Long, Fei; Wang, Weiming; Du, Jingjing; Zou, Zhengguang

    2009-03-01

    The precursors of CIS and CIGS thin films were prepared by one-step electrodeposition in alcohol solution and then annealed in Ar atmosphere at 550°C for 30min. The influences of deposition potentials and salt concentrations on the morphology and composition of the thin films were studied in details. The films were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM), and energy-dispersive X-ray spectroscopy(EDS). The results show that annealed films have pure CIS or CIGS phases with good crystallization and the morphology of the films are very uniform and dense. The high quality precursor films were obtained using optimized deposition parameters. Moreover the electrodeposition mechanism of CIS thin films was briefly discussed.

  9. Time-resolving analysis of cryotropic gelation of water/poly(vinyl alcohol) solutions via small-angle neutron scattering.

    PubMed

    Auriemma, Finizia; De Rosa, Claudio; Ricciardi, Rosa; Lo Celso, Fabrizio; Triolo, Roberto; Pipich, Vitaly

    2008-01-24

    The structural transformations occurring in initially homogeneous aqueous solutions of poly(vinyl alcohol) (PVA) through application of freezing (-13 degrees C) and thawing (20 degrees C) cycles is investigated by time resolving small-angle neutron scattering (SANS). These measurements indicate that formation of gels of complex hierarchical structure arises from occurrence of different elementary processes, involving different length and time scales. The fastest process that could be detected by our measurements during the first cryotropic treatment consists of the crystallization of the solvent. However, solvent crystallization is incomplete, and an unfrozen liquid microphase more concentrated in PVA than the initial solution is also formed. Crystallization of PVA takes place inside the unfrozen liquid microphase and is slowed down because of formation of a microgel fraction. Water crystallization takes place in the early 10 min of the treatment of the solution at subzero temperatures, and although below 0 degrees C the PVA solutions used for preparation of cryogels should be below the spinodal curve, occurrence of liquid-liquid phase separation could not be detected in our experiments. Upon thawing, ice crystals melt, and transparent gels are obtained that become opaque in approximately 200 min, due to a slow and progressive increase of the size of microheterogeneities (dilute and dense regions) imprinted during the fast freezing by the crystallization of water. During the permanence of these gels at room temperature (for hours), the presence of a high content of water (higher than 85% by mass) prevents further crystallization of PVA. Crystallization of PVA, in turn, is resumed by freezing the gels at subzero temperatures, after water crystallization and consequent formation of an unfrozen microphase. The kinetic parameters of PVA crystallization during the permanence of these gels at subzero temperatures are the same shown by PVA during the first freezing step

  10. Extraction of actinides into aqueous polyethylene glycol solutions from carbonate media in the presence of alizarin complexone

    SciTech Connect

    Molochnikova, N.P.; Frenkel', V.Ya.; Myasoedov, B.F.; Shkinev, V.M.; Spivakov, B.Ya.; Zolotov, Yu.A.

    1987-01-01

    Actinide extraction in a two-phase aqueous system based on polyethylene glycol from carbonate solutions of various compositions in presence of alizarin complexone is studied. It is shown that the nature of the alkali metals affects actinide extraction into the polyethylene glycol phase. Tri- and tetravalent actinides are extracted maximally from sodium carbonate solutions. Separation of actinides in different oxidation states is more effective in potassium carbonate solutions. The behavior of americium in different oxidation states in the system carbonate-polyethylene glycol-complexone is studied. The possibility of extraction separation of microamount of americium(V) from curium in carbonate solutions in presence of alizarin complexone is shown.

  11. Alcohol-induced One-carbon Metabolism Impairment Promotes Dysfunction of DNA Base Excision Repair in Adult Brain*

    PubMed Central

    Fowler, Anna-Kate; Hewetson, Aveline; Agrawal, Rajiv G.; Dagda, Marisela; Dagda, Raul; Moaddel, Ruin; Balbo, Silvia; Sanghvi, Mitesh; Chen, Yukun; Hogue, Ryan J.; Bergeson, Susan E.; Henderson, George I.; Kruman, Inna I.

    2012-01-01

    The brain is one of the major targets of chronic alcohol abuse. Yet the fundamental mechanisms underlying alcohol-mediated brain damage remain unclear. The products of alcohol metabolism cause DNA damage, which in conditions of DNA repair dysfunction leads to genomic instability and neural death. We propose that one-carbon metabolism (OCM) impairment associated with long term chronic ethanol intake is a key factor in ethanol-induced neurotoxicity, because OCM provides cells with DNA precursors for DNA repair and methyl groups for DNA methylation, both critical for genomic stability. Using histological (immunohistochemistry and stereological counting) and biochemical assays, we show that 3-week chronic exposure of adult mice to 5% ethanol (Lieber-Decarli diet) results in increased DNA damage, reduced DNA repair, and neuronal death in the brain. These were concomitant with compromised OCM, as evidenced by elevated homocysteine, a marker of OCM dysfunction. We conclude that OCM dysfunction plays a causal role in alcohol-induced genomic instability in the brain because OCM status determines the alcohol effect on DNA damage/repair and genomic stability. Short ethanol exposure, which did not disturb OCM, also did not affect the response to DNA damage, whereas additional OCM disturbance induced by deficiency in a key OCM enzyme, methylenetetrahydrofolate reductase (MTHFR) in Mthfr+/− mice, exaggerated the ethanol effect on DNA repair. Thus, the impact of long term ethanol exposure on DNA repair and genomic stability in the brain results from OCM dysfunction, and MTHFR mutations such as Mthfr 677C→T, common in human population, may exaggerate the adverse effects of ethanol on the brain. PMID:23118224

  12. Methods of pretreating comminuted cellulosic material with carbonate-containing solutions

    DOEpatents

    Francis, Raymond

    2012-11-06

    Methods of pretreating comminuted cellulosic material with an acidic solution and then a carbonate-containing solution to produce a pretreated cellulosic material are provided. The pretreated material may then be further treated in a pulping process, for example, a soda-anthraquinone pulping process, to produce a cellulose pulp. The pretreatment solutions may be extracted from the pretreated cellulose material and selectively re-used, for example, with acid or alkali addition, for the pretreatment solutions. The resulting cellulose pulp is characterized by having reduced lignin content and increased yield compared to prior art treatment processes.

  13. Regeneration of granular activated carbon saturated with acetone and isopropyl alcohol via a recirculation process under H2O2/UV oxidation.

    PubMed

    Horng, Richard S; Tseng, I-Chin

    2008-06-15

    This study examines a water-based system, coupling an adsorber and a photoreactor, for regeneration of granular activated carbon (GAC) saturated with acetone and isopropyl alcohol (IPA). Through water recirculation the regeneration reaction was operated in both intermittent and continuous ultraviolet illumination modes. With a periodic dosage of hydrogen peroxide not only was regeneration efficient but it was also catalyzed by GAC in the adsorber. The concentrations of acetone, solution chemical oxygen demand (COD), pH and organic residues on GAC surfaces were measured during regenerations. Both pH and solution COD were found to correlate with regeneration completion as measured by organic residue on GAC surfaces in four regeneration cycles with acetone. Solution pH decreased to the acidic values and then returned to near its original value when organic residues were 0.085-0.255 mg/g GAC, that is, destruction efficiency of adsorbed acetone on the GAC surface was more than 99%. Likewise, solution COD became low (<100 mg/l) at regeneration completion. The pH variation pattern was then applied to another four cycles of regeneration with IPA, and successfully reflected the timing of complete regeneration. The final levels of organic residue on GAC surfaces were between 0.135 and 0.310 mg/g GAC in each of four regeneration cycles, each of which had been stopped based on the measurements of pH and solution COD. Furthermore, nearly the same batch of GAC could be repeatedly used with little changes in physicochemical properties in each of eight cycles: adsorptive capacities were 95+/-7 mg acetone/g GAC and 87+/-3 mg IPA/g GAC, and breakthrough time was 0.86+/-0.05 for acetone and 0.78+/-0.03 h for IPA. An economic assessment of the system showed that the operating cost was about 0.04 USD for treating every gram of acetone in the air.

  14. Electrochemical formation of hydroxide for enhancing carbon dioxide and acid gas uptake by a solution

    DOEpatents

    Rau, Gregory Hudson

    2012-05-15

    A system is described for forming metal hydroxide from a metal carbonate utilizing a water electrolysis cell having an acid-producing anode and a hydroxyl-producing cathode immersed in a water solution of sufficient ionic content to allow an electric current to pass between the hydroxyl-producing cathode and the acid-producing anode. A metal carbonate, in particular water-insoluble calcium carbonate or magnesium carbonate, is placed in close proximity to the acid-producing anode. A direct current electrical voltage is provided across the acid-producing anode and the hydroxyl-producing cathode sufficient to generate acid at the acid-producing anode and hydroxyl ions at the hydroxyl-producing cathode. The acid dissolves at least part of the metal carbonate into metal and carbonate ions allowing the metal ions to travel toward the hydroxyl-producing cathode and to combine with the hydroxyl ions to form the metal hydroxide. The carbonate ions travel toward the acid-producing anode and form carbonic acid and/or water and carbon dioxide. Among other uses, the metal hydroxide formed can be employed to absorb acid gases such as carbon dioxide from a gas mixture. The invention can also generate hydrogen and oxidative gases such as oxygen or chlorine.

  15. Density and viscosity of some partially carbonated aqueous alkanolamine solutions and their blends

    SciTech Connect

    Weiland, R.H.; Dingman, J.C.; Cronin, D.B.; Browning, G.J.

    1998-05-01

    Very little information is available concerning the effect of acid gas loading on the physical properties of amine-treating solutions flowing through the absorption and regeneration columns used in gas processing. The densities and viscosities of partially carbonated monoethanolamine (MEA), diethanolamine (DEA), and N-methyldiethanolamine (MDEA) solutions were measured at 298 K. With increasing carbon dioxide loadings, significant increases in both density and viscosity were observed. These results were combined with literature data to produce correlations for alkanolamine solution density and viscosity as a function of amine concentration, carbon dioxide loading, and temperature. The resulting single-amine correlations were used to predict the densities and viscosities of DEA + MDEA and MEA + MDEA blends. Predictions are compared with data measured for these blends.

  16. Adsorption of Basic Violet 14 in aqueous solutions using KMnO4-modified activated carbon.

    PubMed

    Shi, Qianqian; Zhang, Jian; Zhang, Chenglu; Nie, Wei; Zhang, Bo; Zhang, Huayong

    2010-03-01

    In this paper, an activated carbon was prepared from Typha orientalis and then treated with KMnO(4) and used for the removal of Basic Violet 14 from aqueous solutions. KMnO(4) treatment influenced the physicochemical properties of the carbon and improved its adsorption capacity. Adsorption experiments were then conducted with KMnO(4)-modified activated carbon to study the effects of carbon dosage (250-1500 mg/L), pH (2-10), ion strength (0-0.5 mol/L), temperature, and contact time on the adsorption of Basic Violet 14 from aqueous solutions. The equilibrium data were analyzed by the Langmuir and Freundlich isotherms and fitted well with the Langmuir model. The pseudo-first-order, pseudo-second-order, and intraparticle diffusion models were used to evaluate the kinetic data and the pseudo-second-order kinetics was the best with good correlation.

  17. Optoelectronically automated system for carbon nanotubes synthesis via arc-discharge in solution

    NASA Astrophysics Data System (ADS)

    Bera, Debasis; Brinley, Erik; Kuiry, Suresh C.; McCutchen, Matthew; Seal, Sudipta; Heinrich, Helge; Kabes, Bradley

    2005-03-01

    The method of arc discharge in the solution is unique and inexpensive route for synthesis of the carbon nanotubes (CNTs), carbon onions, and other carbon nanostructures. Such a method can be used for in situ synthesis of CNTs decorated with nanoparticles. Herein, we report a simple and inexpensive optoelectronically automated system for arc discharge in solution synthesis of CNTs. The optoelectronic system maintains a constant gap between the two electrodes allowing a continuous synthesis of the carbon nanostructures. The system operates in a feedback loop consisting of an electrode-gap detector and an analog electronic unit, as controller. This computerized feeding system of the anode was used for in situ nanoparticles incorporated CNTs. For example, we have successfully decorated CNTs with ceria, silica, and palladium nanoparticles. Characterizations of nanostructures are performed using high-resolution transmission electron microscopy, scanning transmission electron microscopy, energy dispersive spectroscopy, and scanning electron microscopy.

  18. AC-conductance and capacitance measurements for ethanol vapor detection using carbon nanotube-polyvinyl alcohol composite based devices.

    PubMed

    Greenshields, Márcia W C C; Meruvia, Michelle S; Hümmelgen, Ivo A; Coville, Neil J; Mhlanga, Sabelo D; Ceragioli, Helder J; Quispe, Jose C Rojas; Baranauskas, Vitor

    2011-03-01

    We report the preparation of inexpensive ethanol sensor devices using multiwalled carbon nanotube-polyvinyl alcohol composite films deposited onto interdigitated electrodes patterned on phenolite substrates. We investigate the frequency dependent response of the device conductance and capacitance showing that higher sensitivity is obtained at higher frequency if the conductance is used as sensing parameter. In the case of capacitance measurements, higher sensitivity is obtained at low frequency. Ethanol detection at a concentration of 300 ppm in air is demonstrated. More than 80% of the sensor conductance and capacitance variation response occurs in less than 20 s.

  19. Dry-spraying of ascorbic acid or acetaminophen solutions with supercritical carbon dioxide

    NASA Astrophysics Data System (ADS)

    Wubbolts, F. E.; Bruinsma, O. S. L.; van Rosmalen, G. M.

    1999-03-01

    Carbon dioxide is a very poor solvent for many organic compounds, which makes it a good anti-solvent. When a solution is sprayed into carbon dioxide vapour the anti-solvent reduces the solubility within several tens of milliseconds and the solute precipitates. Two distinct regions can be identified, below and above the mixture critical pressure. Below this critical pressure the yield remains relatively low and the process is not well controlled. Above the critical pressure small crystals are obtained of about 2 μm with a yield of 90%.

  20. Accelerated nanoparticles synthesis in alcohol-water-mixture-based solution plasma.

    PubMed

    Sudare, Tomohito; Ueno, Tomonaga; Watthanaphanit, Anyarat; Saito, Nagahiro

    2015-11-11

    An extraordinary high-speed synthesis of gold nanoparticles (AuNPs) was discovered by synthesizing the AuNPs in ethanol-water mixtures using a solution plasma process (SPP). The influence of the ethanol mole fraction (χethanol) in the ethanol-water mixtures on the reduction rate of gold chloride ions to AuNPs under the SPP system was studied. The results indicated that the reaction rate of the AuNPs synthesis exhibited a maximum value (i.e. 35.2 times faster than in a pure water system) at the significant point where the partial molar volumes of ethanol and water changed drastically.

  1. Effect of alcohol aggregation on the retention factors of chiral solutes with an amylose-based sorbent: modeling and implications for the adsorption mechanism.

    PubMed

    Tsui, Hung-Wei; Franses, Elias I; Wang, Nien-Hwa Linda

    2014-02-01

    Various displacement models in the literature have been widely used for understanding the adsorption mechanisms of solutes in various chromatography systems. The models were used for describing the often-observed linear plots of the logarithms of the retention factor versus the logarithms of the polar modifier concentration CI(0). The slopes of such a plot was inferred to be equal to the number of the displaced modifier molecules upon adsorption of one solute molecule, and were generally found to be greater than 1. In this study, the retention factors of four structurally related chiral solutes, ethyl lactate (EL), methyl mandelate (MM), benzoin (B), and pantolactone (PL), were measured for the amylose tris[(S)-α-methylbenzylcarbamate] sorbent, or AS, as a function of the concentration of isopropanol (IPA) in n-hexane. With increasing IPA concentration CI(0), the slopes increase from less than 1, at a concentration range from 0.13 to 1.3M, to slightly more than 1 at higher concentrations. Such slopes cannot be explained by the conventional retention models. It was found previously for monovalent solutes that such slopes can only be explained when the aggregation of the mobile phase modifier, isopropyl alcohol, was accounted for. A new retention model is presented here, accounting for alcohol aggregation, multivalent solute adsorption, multivalent solute-alcohol complexation, alcohol adsorption, and solute intra hydrogen-bonding, which occur in these four solutes. The slope is found to be controlled by three key dimensionless groups, the fraction of the sorbent binding sites covered by IPA, the fraction of the solute molecules in complex form, and the fraction of the IPA molecules in aggregate form. The limiting slope at a very high IPA concentration is equal to the value of (x+y)/n, where x is the number of the solute-sorbent binding sites and y is the number of the alcohol molecules in the solute-alcohol complex, and n is the alcohol aggregation number. The model

  2. Competitive adsorption of phenolic compounds from aqueous solution using sludge-based activated carbon.

    PubMed

    Mohamed, E F; Andriantsiferana, C; Wilhelm, A M; Delmas, H

    2011-01-01

    Preparation of activated carbon from sewage sludge is a promising approach to produce cheap and efficient adsorbent for pollutants removal as well as to dispose of sewage sludge. The first objective of this study was to investigate the physical and chemical properties (BET surface area, ash and elemental content, surface functional groups by Boehm titration and weight loss by thermogravimetric analysis) of the sludge-based activated carbon (SBAC) so as to give a basic understanding of its structure and to compare to those of two commercial activated carbons, PICA S23 and F22. The second and main objective was to evaluate the performance of SBAC for single and competitive adsorption of four substituted phenols (p-nitrophenol, p-chlorophenol, p-hydroxy benzoic acid and phenol) from their aqueous solutions. The results indicated that, despite moderate micropore and mesopore surface areas, SBAC had remarkable adsorption capacity for phenols, though less than PICA carbons. Uptake of the phenolic compound was found to be dependent on both the porosity and surface chemistry of the carbons. Furthermore, the electronegativity and the hydrophobicity of the adsorbate have significant influence on the adsorption capacity. The Langmuir and Freundlich models were used for the mathematical description of the adsorption equilibrium for single-solute isotherms. Moreover, the Langmuir-Freundlich model gave satisfactory results for describing multicomponent system isotherms. The capacity of the studied activated carbons to adsorb phenols from a multi-solute system was in the following order: p-nitrophenol > p-chlorophenol > PHBA > phenol.

  3. Recycled Poly(vinyl alcohol) Sponge for Carbon Encapsulation of Size-Tunable Tin Dioxide Nanocrystalline Composites.

    PubMed

    Ma, Yue; Tai, Cheuk-Wai; Gustafsson, Torbjörn; Edström, Kristina

    2015-06-22

    The recycling of industrial materials could reduce their environmental impact and waste haulage fees and result in sustainable manufacturing. In this work, commercial poly(vinyl alcohol) (PVA) sponges are recycled into a macroporous carbon matrix to encapsulate size-tunable SnO2 nanocrystals as anode materials for lithium-ion batteries (LIBs) through a scalable, flash-combustion method. The hydroxyl groups present copiously in the recycled PVA sponges guarantee a uniform chemical coupling with a tin(IV) citrate complex through intermolecular hydrogen bonds. Then, a scalable, ultrafast combustion process (30 s) carbonizes the PVA sponge into a 3D carbon matrix. This PVA-sponge-derived carbon could not only buffer the volume fluctuations upon the Li-Sn alloying and dealloying processes but also afford a mixed conductive network, that is, a continuous carbon framework for electrical transport and macropores for facile electrolyte percolation. The best-performing electrode based on this composite delivers a rate performance up to 9.72 C (4 A g(-1) ) and long-term cyclability (500 cycles) for Li(+) ion storage. Moreover, cyclic voltammograms demonstrate the coexistence of alloying and dealloying processes and non-diffusion-controlled pseudocapacitive behavior, which collectively contribute to the high-rate Li(+) ion storage. PMID:26033927

  4. Recycled Poly(vinyl alcohol) Sponge for Carbon Encapsulation of Size-Tunable Tin Dioxide Nanocrystalline Composites.

    PubMed

    Ma, Yue; Tai, Cheuk-Wai; Gustafsson, Torbjörn; Edström, Kristina

    2015-06-22

    The recycling of industrial materials could reduce their environmental impact and waste haulage fees and result in sustainable manufacturing. In this work, commercial poly(vinyl alcohol) (PVA) sponges are recycled into a macroporous carbon matrix to encapsulate size-tunable SnO2 nanocrystals as anode materials for lithium-ion batteries (LIBs) through a scalable, flash-combustion method. The hydroxyl groups present copiously in the recycled PVA sponges guarantee a uniform chemical coupling with a tin(IV) citrate complex through intermolecular hydrogen bonds. Then, a scalable, ultrafast combustion process (30 s) carbonizes the PVA sponge into a 3D carbon matrix. This PVA-sponge-derived carbon could not only buffer the volume fluctuations upon the Li-Sn alloying and dealloying processes but also afford a mixed conductive network, that is, a continuous carbon framework for electrical transport and macropores for facile electrolyte percolation. The best-performing electrode based on this composite delivers a rate performance up to 9.72 C (4 A g(-1) ) and long-term cyclability (500 cycles) for Li(+) ion storage. Moreover, cyclic voltammograms demonstrate the coexistence of alloying and dealloying processes and non-diffusion-controlled pseudocapacitive behavior, which collectively contribute to the high-rate Li(+) ion storage.

  5. Selective synthesis and device applications of semiconducting single-walled carbon nanotubes using isopropyl alcohol as feedstock.

    PubMed

    Che, Yuchi; Wang, Chuan; Liu, Jia; Liu, Bilu; Lin, Xue; Parker, Jason; Beasley, Cara; Wong, H-S Philip; Zhou, Chongwu

    2012-08-28

    The development of guided chemical vapor deposition (CVD) growth of single-walled carbon nanotubes provides a great platform for wafer-scale integration of aligned nanotubes into circuits and functional electronic systems. However, the coexistence of metallic and semiconducting nanotubes is still a major obstacle for the development of carbon-nanotube-based nanoelectronics. To address this problem, we have developed a method to obtain predominantly semiconducting nanotubes from direct CVD growth. By using isopropyl alcohol (IPA) as the carbon feedstock, a semiconducting nanotube purity of above 90% is achieved, which is unambiguously confirmed by both electrical and micro-Raman measurements. Mass spectrometric study was performed to elucidate the underlying chemical mechanism. Furthermore, high performance thin-film transistors with an on/off ratio above 10(4) and mobility up to 116 cm(2)/(V·s) have been achieved using the IPA-synthesized nanotube networks grown on silicon substrate. The method reported in this contribution is easy to operate and the results are highly reproducible. Therefore, such semiconducting predominated single-walled carbon nanotubes could serve as an important building block for future practical and scalable carbon nanotube electronics.

  6. Free-energy landscape of alcohol driven coacervation transition in aqueous gelatin solutions

    NASA Astrophysics Data System (ADS)

    Gupta, Amarnath; Reena, Bohidar, H. B.

    2006-08-01

    Liquid-liquid phase separation of a homogeneous polyampholyte (gelatin) solution into a dense polymer-rich coacervate and the dilute supernatant phase is discussed through free-energy landscape formalism. We have evaluated the free energy and entropy of the system as it undergoes the phenomenon of simple coacervation, driven by the addition of a nonsolvent. Electrophoretic mobility (μ) and turbidity measurements were performed on 0.01% and 0.05%(w/v) aqueous gelatin solutions that were driven towards coacervation by the addition of ethanol. The mobility of the polyampholyte molecules, which was typically μ ≈0.38±0.02μm/scm/V in water, gradually reduced for the soluble intermolecular complexes to a plateau value of μ ≈0.11±0.01μm/scm/V as the ethanol volume fraction equaled φns≈0.47±0.03, which coincided with the first appearance of coacervate droplets (coacervation transition) observed from turbidity measurements, a behavior found to be invariant of gelatin concentration. These results were used as input to the theoretical model to explicitly construct the free-energy landscape for a single gelatin chain and the global system comprising the polymer-rich coacervate and the dilute supernatant phase.

  7. Effects of dilute substitutional solutes on interstitial carbon in α-Fe: Interactions and associated carbon diffusion from first-principles calculations

    NASA Astrophysics Data System (ADS)

    Liu, Peitao; Xing, Weiwei; Cheng, Xiyue; Li, Dianzhong; Li, Yiyi; Chen, Xing-Qiu

    2014-07-01

    By means of first-principles calculations coupled with the kinetic Monte Carlo simulations, we have systematically investigated the effects of dilute substitutional solutes on the behaviors of carbon in α-Fe. Our results uncover the following. (i) Without the Fe vacancy the interactions between most solutes and carbon are repulsive due to the strain relief, whereas Mn has a weak attractive interaction with its nearest-neighbor carbon due to the local ferromagnetic coupling effect. (ii) The presence of the Fe vacancy results in attractive interactions of all the solutes with carbon. In particular, the Mn-vacancy pair shows an exceptionally large binding energy of -0.81 eV with carbon. (iii) The alloying addition significantly impacts the atomic-scale concentration distributions and chemical potential of carbon in the Fe matrix. Among them, Mn and Cr increase the carbon chemical potential, whereas Al and Si reduce it. (iv) Within the dilute scale of the alloying solution, the solute concentration- and temperature-dependent carbon diffusivities demonstrate that Mn has a little impact on the carbon diffusion, whereas Cr (Al or Si) remarkably retards the carbon diffusion. Our results provide a certain implication for better understanding the experimental observations related with the carbon solubility limit, carbon microsegregation, and carbide precipitations in the ferritic steels.

  8. Anomalously enhanced hydration of aqueous electrolyte solution in hydrophobic carbon nanotubes to maintain stability.

    PubMed

    Ohba, Tomonori

    2014-02-24

    An understanding of the structure and behavior of electrolyte solutions in nanoenvironements is crucial not only for a wide variety of applications, but also for the development of physical, chemical, and biological processes. We demonstrate the structure and stability of electrolyte in carbon nanotubes using hybrid reverse Monte Carlo simulations of X-ray diffraction patterns. Hydrogen bonds between water are adequately formed in carbon nanotubes, although some hydrogen bonds are restricted by the interfaces of carbon nanotubes. The hydrogen bonding network of water in electrolyte in the carbon nanotubes is further weakened. On the other hand, formation of the ion hydration shell is significantly enhanced in the electrolyte in the carbon nanotubes in comparison to ion hydration in bulk electrolyte. The significant hydrogen bond and hydration shell formation are a result of gaining stability in the hydrophobic nanoenvironment.

  9. Solution and shock-induced exsolution of argon in vitreous carbon

    NASA Technical Reports Server (NTRS)

    Gazis, Carey; Ahrens, Thomas J.

    1991-01-01

    To add to the knowledge of noble gas solution and exsolution in carbonaceus material, experiments were performed on vitreous carbon. Ar-rich vitreous carbon samples were prepared under vapor-saturated conditions using argon as the pressurizing medium. Solubility data were obtained for temperatures of 773 to 973 K and pressures of 250 to 1500 bars. Up to 7 wt pct Ar was dissolved in the carbon. The solubility data were compared to a thermodynamic model of argon atoms dissolving into a fixed population of 'holes' in the carbon. Two variations of the model yielded estimates of the enthalpy of solution of Ar in vitreous carbon equal to about -4700 cal/mole. Preliminary shock experiments showed that 28 percent of the total argon was released by driving 4 GPa shocks into the argon-rich carbon. It was demonstrated that shock-induced argon loss is not simply caused by the impact-induced diminution of grain size. The present value of shock pressure required for partial impact devolatilization of Ar from carbon is below the range (5-30 GPa) at which H2O is released from phyllosilicates.

  10. Removal of nitroimidazole antibiotics from aqueous solution by adsorption/bioadsorption on activated carbon.

    PubMed

    Rivera-Utrilla, J; Prados-Joya, G; Sánchez-Polo, M; Ferro-García, M A; Bautista-Toledo, I

    2009-10-15

    The objective of the present study was to analyse the behaviour of activated carbon with different chemical and textural properties in nitroimidazole adsorption, also assessing the combined use of microorganisms and activated carbon in the removal of these compounds from waters and the influence of the chemical nature of the solution (pH and ionic strength) on the adsorption process. Results indicate that the adsorption of nitroimidazoles is largely determined by activated carbon chemical properties. Application of the Langmuir equation to the adsorption isotherms showed an elevated adsorption capacity (X(m)=1.04-2.04 mmol/g) for all contaminants studied. Solution pH and electrolyte concentration did not have a major effect on the adsorption of these compounds on activated carbon, confirming that the principal interactions involved in the adsorption of these compounds are non-electrostatic. Nitroimidazoles are not degraded by microorganisms used in the biological stage of a wastewater treatment plant. However, the presence of microorganisms during nitroimidazole adsorption increased their adsorption on the activated carbon, although it weakened interactions between the adsorbate and carbon surface. In dynamic regime, the adsorptive capacity of activated carbon was markedly higher in surface water and groundwater than in urban wastewaters.

  11. Integrated ternary artificial nacre via synergistic toughening of reduced graphene oxide/double-walled carbon nanotubes/poly(vinyl alcohol)

    NASA Astrophysics Data System (ADS)

    Gong, Shanshan; Wu, Mengxi; Jiang, Lei; Cheng, Qunfeng

    2016-07-01

    The synergistic toughening effect of building blocks and interface interaction exists in natural materials, such as nacre. Herein, inspired by one-dimensional (1D) nanofibrillar chitin and two-dimensional (2D) calcium carbonate platelets of natural nacre, we have fabricated integrated strong and tough ternary bio-inspired nanocomposites (artificial nacre) successfully via the synergistic effect of 2D reduced graphene oxide (rGO) nanosheets and 1D double-walled carbon nanotubes (DWNTs) and hydrogen bonding cross-linking with polyvinyl alcohol (PVA) matrix. Moreover, the crack mechanics model with crack deflection by 2D rGO nanosheets and crack bridging by 1D DWNTs and PVA chains induces resultant artificial nacre exhibiting excellent fatigue-resistance performance. These outstanding characteristics enable the ternary bioinspired nanocomposites have many promising potential applications, for instance, aerospace, flexible electronics devices and so forth. This synergistic toughening strategy also provides an effective way to assemble robust graphene-based nanocomposites.

  12. Alcoholism and Alcohol Abuse

    MedlinePlus

    ... This means that their drinking causes distress and harm. It includes alcoholism and alcohol abuse. Alcoholism, or ... brain, and other organs. Drinking during pregnancy can harm your baby. Alcohol also increases the risk of ...

  13. Investigation into the structural composition of hydroalcoholic solutions as basis for the development of multiple suppression pulse sequences for NMR measurement of alcoholic beverages.

    PubMed

    Monakhova, Yulia B; Mushtakova, Svetlana P; Kuballa, Thomas; Lachenmeier, Dirk W

    2014-12-01

    An eight-fold suppression pulse sequence was recently developed to improve sensitivity in (1) H NMR measurements of alcoholic beverages [Magn. Res. Chem. 2011 (49): 734-739]. To ensure that only one combined hydroxyl peak from water and ethanol appears in the spectrum, adjustment to a certain range of ethanol concentrations was required. To explain this observation, the structure of water-ethanol solutions was studied. Hydroalcoholic solutions showed extreme behavior at 25% vol, 46% vol, and 83% vol ethanol according to (1) H NMR experiments. Near-infrared spectroscopy confirmed the occurrence of four significant compounds ('individual' ethanol and water structures as well as two water-ethanol complexes of defined composition - 1 : 1 and 1 : 3). The successful multiple suppression can be achieved for every kind of alcoholic beverage with different alcoholic strengths, when the final ethanol concentration is adjusted to a range between 25% vol and 46% vol (e.g. using dilution or pure ethanol addition). In this optimum region, an individual ethanol peak was not detected, because the 'individual' water structure and the 1 : 1 ethanol-water complex predominate. The nature of molecular association in ethanol-water solutions is essential to elucidate NMR method development for measurement of alcoholic beverages. The presented approach can be used to optimize other NMR suppression protocols for binary water-organic solvent mixtures, where hydrogen bonding plays a dominant role.

  14. Effect of UV and electrochemical surface treatments on the adsorption and reaction of linear alcohols on non-porous carbon fibre

    NASA Astrophysics Data System (ADS)

    Osbeck, S.; Ward, S.; Idriss, H.

    2013-04-01

    The adsorption properties of untreated, electrochemically treated and ultra-violet/ozone treated polyacrylonitrile based carbon fibres were investigated using temperature programmed desorption (TPD) on a series of linear alcohols as probes in order to understand its surface properties. Surface uptake was found to be sensitive to both the surface treatment and the nature of the adsorbates. Surface coverage increased with increasing alcohol chain due to the increase in their polarizability. It also increased with the level of surface oxygen of the fibres most likely because it facilitates the Osbnd H bond dissociation of the alcohol functional group. In addition, the desorption temperature (during TPD) tracked the surface oxygen levels (as determined from XPS O1s signal) suggesting increasing in the adsorption energy. The reactions of C1-C4 linear alcohols were also investigated on the surface of the fibre carbon. The main reaction was dehydrogenation to the corresponding aldehydes; the dehydration reaction to olefins was not observed. The dehydrogenation reaction was sensitive to the length of the alky chain. It was highest for methanol (to formaldehyde) and decreased with increasing the carbon number. Overall TPD of linear alcohols was shown to be a promising method for quantifying the level and strength of bonding occurring on carbon fibre surfaces.

  15. Minimally refined biomass fuel. [carbohydrate-water-alcohol mixture

    SciTech Connect

    Pearson, R.K.; Hirschfeld, T.B.

    1981-03-26

    A minimally refined fluid composition, suitable as a fuel mixture and derived from biomass material, is comprised of one or more water-soluble carbohydrates such as sucrose, one or more alcohols having less than four carbons, and water. The carbohydrate provides the fuel source; water-solubilizes the carbohydrate; and the alcohol aids in the combustion of the carbohydrate and reduces the viscosity of the carbohydrate/water solution. Because less energy is required to obtain the carbohydrate from the raw biomass than alcohol, an overall energy savings is realized compared to fuels employing alcohol as the primary fuel.

  16. Efficacy and safety of a quick drying rubbing type povidone-iodine alcoholic disinfectant solution.

    PubMed

    Kirita, T; Hamano, K; Ochi, T; Ihara, H; Nishiyama, T; Seshimo, A; Yagi, Y; Sakakida, K

    1993-01-01

    The efficacy and safety of a quick drying rubbing type disinfectant (HAD Hand Wash) composed of a povidone-iodine (PVP-I) and ethanol were evaluated in the disinfection of transient skin flora on fingers of 30 medical staff of our department. Three millilitres of HAD solution was rubbed onto the hands for three minutes several times a day over a four week period. Bacteriological effects were evaluated twice, on the first day and after four weeks, by the palm stamp method. The rate of colonies sterilized (bacterial reduction rate) after the use of HAD Hand Wash was 86.9 +/- 21.2% (mean +/- SD) on the first measurement, and 91.5% +/- 12.8% at four weeks. Staphylococcus epidermidis was isolated most frequently and this was eradicated in 83.3% of subjects, the bacterial reduction rate 99.7%. Staphylococcus aureus was originally isolated in 14 subjects and was eradicated in 13; the bacterial colony reduction rate was 99.9% showing high antiseptic efficacy. Although the bacterial reduction rate for Bacillus sp. was a rather low, 75.8-100%, this result was not considered problematic from the clinical standpoint. There were no side effects like chapping in spite of an average 104 applications of HAD Hand Wash during the 4-week test period. From these results, HAD Hand Wash was considered highly effective and safe.

  17. The Anion Effect on Li(+) Ion Coordination Structure in Ethylene Carbonate Solutions.

    PubMed

    Jiang, Bo; Ponnuchamy, Veerapandian; Shen, Yuneng; Yang, Xueming; Yuan, Kaijun; Vetere, Valentina; Mossa, Stefano; Skarmoutsos, Ioannis; Zhang, Yufan; Zheng, Junrong

    2016-09-15

    Rechargeable lithium ion batteries are an attractive alternative power source for a wide variety of applications. To optimize their performances, a complete description of the solvation properties of the ion in the electrolyte is crucial. A comprehensive understanding at the nanoscale of the solvation structure of lithium ions in nonaqueous carbonate electrolytes is, however, still unclear. We have measured by femtosecond vibrational spectroscopy the orientational correlation time of the CO stretching mode of Li(+)-bound and Li(+)-unbound ethylene carbonate molecules, in LiBF4, LiPF6, and LiClO4 ethylene carbonate solutions with different concentrations. Surprisingly, we have found that the coordination number of ethylene carbonate in the first solvation shell of Li(+) is only two, in all solutions with concentrations higher than 0.5 M. Density functional theory calculations indicate that the presence of anions in the first coordination shell modifies the generally accepted tetrahedral structure of the complex, allowing only two EC molecules to coordinate to Li(+) directly. Our results demonstrate for the first time, to the best of our knowledge, the anion influence on the overall structure of the first solvation shell of the Li(+) ion. The formation of such a cation/solvent/anion complex provides a rational explanation for the ionic conductivity drop of lithium/carbonate electrolyte solutions at high concentrations. PMID:27560477

  18. The Anion Effect on Li(+) Ion Coordination Structure in Ethylene Carbonate Solutions.

    PubMed

    Jiang, Bo; Ponnuchamy, Veerapandian; Shen, Yuneng; Yang, Xueming; Yuan, Kaijun; Vetere, Valentina; Mossa, Stefano; Skarmoutsos, Ioannis; Zhang, Yufan; Zheng, Junrong

    2016-09-15

    Rechargeable lithium ion batteries are an attractive alternative power source for a wide variety of applications. To optimize their performances, a complete description of the solvation properties of the ion in the electrolyte is crucial. A comprehensive understanding at the nanoscale of the solvation structure of lithium ions in nonaqueous carbonate electrolytes is, however, still unclear. We have measured by femtosecond vibrational spectroscopy the orientational correlation time of the CO stretching mode of Li(+)-bound and Li(+)-unbound ethylene carbonate molecules, in LiBF4, LiPF6, and LiClO4 ethylene carbonate solutions with different concentrations. Surprisingly, we have found that the coordination number of ethylene carbonate in the first solvation shell of Li(+) is only two, in all solutions with concentrations higher than 0.5 M. Density functional theory calculations indicate that the presence of anions in the first coordination shell modifies the generally accepted tetrahedral structure of the complex, allowing only two EC molecules to coordinate to Li(+) directly. Our results demonstrate for the first time, to the best of our knowledge, the anion influence on the overall structure of the first solvation shell of the Li(+) ion. The formation of such a cation/solvent/anion complex provides a rational explanation for the ionic conductivity drop of lithium/carbonate electrolyte solutions at high concentrations.

  19. Carbon-13 NMR characterization of actinyl(VI) carbonate complexes in aqueous solution

    SciTech Connect

    Clark, D.L.; Hobart, D.E.; Palmer, P.D.; Sullivan, J.C.; Stout, B.E.

    1992-07-01

    The uranyl(VI) carbonate system has been re-examined using {sup 13}C NMR of 99.9% {sup 13}C-enriched U{sup VI}O{sub 2} ({sup 13}CO{sub 3}){sub 3}{sup 4{minus}} in millimolar concentrations. By careful control of carbonate ion concentration, we have confirmed the existence of the trimer, and observed dynamic equilibrium between the monomer and the timer. In addition, the ligand exchange reaction between free and coordinated carbonate on Pu{sup VI}O{sub 2}({sup 13}CO{sub 3}){sub 3}{sup 4{minus}} and Am{sup VI}O{sub 2}({sup 13}CO{sub 3}){sub 3}{sup 4{minus}} systems has been examined by variable temperature {sup 13}C NMR line-broadening techniques {sup 13}C NMR line-broadening techniques. A modified Carr-Purcell-Meiboom-Gill NMR pulse sequence was written to allow for experimental determination of ligand exchange parameters for paramagnetic actinide complexes. Preliminary Eyring analysis has provided activation parameters of {Delta}G{sup {double_dagger}}{sub 295} = 56 kJ/M, {Delta}H{sup {double_dagger}} = 38 kJ/M, and {Delta}S{sup {double_dagger}} = {minus}60 J/M-K for the plutonyl triscarbonate system, suggesting an associative transition state for the plutonyl (VI) carbonate complex self-exchange reaction. Experiments for determination of the activation parameters for the americium (VI) carbonate system are in progress.

  20. Electrochemical studies of the film formation on lithium in propylene carbonate solutions under open circuit conditions

    SciTech Connect

    Geronov, Y.; Schwager, F.; Muller, R. H.

    1981-06-01

    The nature of protective surface layers formed on lithium in propylene carbonate solutions of and at open circuit has been investigated by electrochemical pulse measurements. The results are consistent with the fast formation of a compact thin layer resulting from the reaction with residual water. This layer acts as a solid ionic conductor. Slow corrosion or decomposition processes produce a thicker porous overlayer.

  1. Sorption of metal ions from multicomponent aqueous solutions by activated carbons produced from waste

    SciTech Connect

    Tikhonova, L.P.; Goba, V.E.; Kovtun, M.F.; Tarasenko, Y.A.; Khavryuchenko, V.D.; Lyubchik, S.B.; Boiko, A.N.

    2008-08-15

    Activated carbons produced by thermal treatment of a mixture of sunflower husks, low-grade coal, and refinery waste were studied as adsorbents of transition ion metals from aqueous solutions of various compositions. The optimal conditions and the mechanism of sorption, as well as the structure of the sorbents, were studied.

  2. Radiolysis of Bicarbonate and Carbonate Aqueous Solutions: Product Analysis and Simulation of Radiolytic Processes

    SciTech Connect

    Cai Zhongli; Li Xifeng; Katsumura, Yosuke; Urabe, Osamu

    2001-11-15

    An understanding of the radiation-induced effects in groundwater is essential to evaluate the safe geological disposal of spent fuel. In groundwater, the bicarbonate ion is the predominant and common anion; this work investigated radiation-induced chemical reactions of (bi)carbonate aqueous solutions with steady-state irradiation and pulse radiolysis methods. Aqueous solutions of sodium (bi)carbonate as high as 50 mmol.dm{sup -3} were used. The formation of formate, oxalate, and H{sub 2}O{sub 2} were measured under different conditions. A complete set of reaction steps and reliable kinetic data for the radiolysis of (bi)carbonate aqueous solutions at ionic strength close to the groundwater were proposed. Kinetic calculations were completed based on the proposed reaction steps and the kinetic data obtained in the present work. The results from the calculation are in good agreement with the experimental results. With these proposed reaction steps and kinetic data, computer simulation can be performed to predict the yield of radiolytic products of (bi)carbonate aqueous solutions as a function of irradiation time and used to evaluate the safety of geological disposal options of spent fuel.

  3. Adsorption Behavior of Ferromagnetic Carbon Nanotubes for Methyl Orange from Aqueous Solution.

    PubMed

    Wang, Liping; Zhang, Mingyu; Zhao, Chenxi; Yang, Shan

    2016-03-01

    The ferromagnetic carbon nanotubes which can be easily separated from aqueous solution were prepared and characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Batch experiments were carried out to investigate the adsorption behavior of ferromagnetic carbon nanotubes for removing methyl orange (MO). The results showed that these ferromagnetic carbon nanotubes were richer in surface function groups than the carbon nanotubes did, furthermore, both γ-Fe2O3 and Fe with ferromagnetism were found on the surface of carbon nanotubes. The results also demonstrated that ferromagnetic carbon nanotubes possessed stronger adsorption ability for MO than carbon nanotubes did. The adsorption isotherms followed Langmuir isotherm equation and the adsorption kinetics could be well described with the pseudo second-order kinetic model. The adsorption process involved an intraparticle diffusion, while it was not the only rate-controlling step. The values of AG were negative and the value of ΔH is -12.37 kJ/mol, proving that the adsorption of MO onto ferromagnetic carbon nanotubes was a spontaneous and exothermic process.

  4. Adsorption Behavior of Ferromagnetic Carbon Nanotubes for Methyl Orange from Aqueous Solution.

    PubMed

    Wang, Liping; Zhang, Mingyu; Zhao, Chenxi; Yang, Shan

    2016-03-01

    The ferromagnetic carbon nanotubes which can be easily separated from aqueous solution were prepared and characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Batch experiments were carried out to investigate the adsorption behavior of ferromagnetic carbon nanotubes for removing methyl orange (MO). The results showed that these ferromagnetic carbon nanotubes were richer in surface function groups than the carbon nanotubes did, furthermore, both γ-Fe2O3 and Fe with ferromagnetism were found on the surface of carbon nanotubes. The results also demonstrated that ferromagnetic carbon nanotubes possessed stronger adsorption ability for MO than carbon nanotubes did. The adsorption isotherms followed Langmuir isotherm equation and the adsorption kinetics could be well described with the pseudo second-order kinetic model. The adsorption process involved an intraparticle diffusion, while it was not the only rate-controlling step. The values of AG were negative and the value of ΔH is -12.37 kJ/mol, proving that the adsorption of MO onto ferromagnetic carbon nanotubes was a spontaneous and exothermic process. PMID:27455713

  5. The critical size of hydrogen-bonded alcohol clusters as effective Brønsted bases in solutions.

    PubMed

    Park, Sun-Young; Kim, Taeg Gyum; Ajitha, Manjaly J; Kwac, Kijeong; Lee, Young Min; Kim, Heesu; Jung, Yousung; Kwon, Oh-Hoon

    2016-09-28

    The alkyl oxonium ion, which is a protonated alcohol, has long been proposed as a key reaction intermediate in alcohol dehydration. Nonetheless, the dynamics and structure of this simple but important intermediate species have not been adequately examined due to the transient nature of the oxonium ion. Here, we devised a model system for the key step in the alcohol dehydration reaction, in which a photoacid transfers a proton to alcohols of different basicity in the acetonitrile solvent. Using time-resolved spectroscopy and computation, we have found that the linkage of at least two alcohol molecules via hydrogen bonding is critical for their enhanced reactivity and extraction of the proton from the acid. This finding addresses the cooperative role of the simplest organic protic compounds, namely alcohols, in nonaqueous acid-base reactions. PMID:27337993

  6. Importance of solute partitioning in biphasic oxidation of benzyl alcohol by free and immobilized whole cells of Pichia pastoris

    SciTech Connect

    Kawakami, Koei; Nakahara, Takehiko . Dept. of Chemical Engineering)

    1994-04-25

    Using free and immobilized whole cells of Pichia pastoris, the biocatalytic oxidation of benzyl alcohol was investigated in different two-phase systems. This reaction was strongly influenced by both the substrate and product inhibitions, and the production rate of benzaldehyde in the aqueous system became maximum at the initial substrate concentration of ca. 29 g/L with the aldehyde formation less than 4 to 5 g/L even after a longer reaction period. The reaction rates in the two-liquid phase systems were predominantly determined by the partitioning behaviors of the substrate and the product between the two phases rather than by enzyme deactivation by the organic solvents. In the two-liquid phase systems, consequently, the organic solvent acted as a reservoir to reduce these inhibitory effects, and it was essential to select the organic solvent providing the optimal partitioning of the substrate into the aqueous phase as well as the preferential extraction of the product into the organic phase. The whole cells immobilized in a mixed matrix composed of silicone polymer and Ca alginate gel worked well in the xylene and decane media, providing comparable activities with the free cells. The production rate of aldehyde was also influenced by the solute partitioning into the hydrophilic alginate phase where the cells existed.

  7. Fluorinated Alcohols as Activators for the Solvent-Free Chemical Fixation of Carbon Dioxide into Epoxides.

    PubMed

    Gennen, Sandro; Alves, Margot; Méreau, Raphaël; Tassaing, Thierry; Gilbert, Bernard; Detrembleur, Christophe; Jerome, Christine; Grignard, Bruno

    2015-06-01

    The addition of fluorinated alcohols to onium salts provides highly efficient organocatalysts for the chemical fixation of CO2 into epoxides under mild experimental conditions. The combination of online kinetic studies, NMR titrations and DFT calculations allows understanding this synergistic effect that provides an active organocatalyst for CO2 /epoxides coupling.

  8. Synthesis of higher alcohols from carbon monoxide and hydrogen in a slurry reactor

    SciTech Connect

    McCutchen, M.S.

    1992-08-28

    Higher, i.e. C{sub 2{sup +}}, alcohols are desired as gasoline additives, feedstocks for producing ethers and as alternative fuels for automobiles. In all cases, the backbone branching of an alcohol improves octane rating, which is essential for good engine performance. These types of branched, higher alcohols are the desired products for a process converting synthesis gas, a CO and H{sub 2} mixture, often generated from coal gasification. Based on this premise, promoted ZnCr oxide catalysts appear to be as one of the best avenues for further investigation. Once this investigation is complete, a natural extension is to replace the Cr in the ZnCr oxide catalyst with Mo and W, both in the same elemental triad with Cr. Mo has already been shown as an active HAS catalyst, both on a SiO{sub 2} support and in the MoS{sub 2} form. The three catalyst combinations, ZnMo, ZnW, and MnCr oxides will be tested in the stirred autoclave system. However, if none of the three indicate any comparable activity and/or selectivity toward higher alcohols as compared with other HAS catalysts, then an investigation of the effects of Cs promotion on the ZnCr oxide methanol catalysts will be executed.

  9. Precipitation of calcium carbonate in aqueous solutions in presence of ethylene glycol and dodecane.

    NASA Astrophysics Data System (ADS)

    Natsi, Panagiota D.; Rokidi, Stamatia; Koutsoukos, Petros G.

    2015-04-01

    The formation of calcium carbonate (CaCO3) in aqueous supersaturated solutions has been intensively studied over the past decades, because of its significance for a number of processes of industrial and environmental interest. In the oil and gas production industry the deposition of calcium carbonate affects adversely the productivity of the wells. Calcium carbonate scale deposits formation causes serious problems in water desalination, CO2 sequestration in subsoil wells, in geothermal systems and in heat exchangers because of the low thermal coefficient of the salt. Amelioration of the operational conditions is possible only when the mechanisms underlying nucleation and crystal growth of calcium carbonate in the aqueous fluids is clarified. Given the fact that in oil production processes water miscible and immiscible hydrocarbons are present the changes of the dielectric constant of the fluid phase has serious impact in the kinetics of calcium carbonate precipitation, which remains largely unknown. The problem becomes even more complicated if polymorphism exhibited by calcium carbonate is also taken into consideration. In the present work, the stability of aqueous solutions supersaturated with respect to all calcium carbonate polymorphs and the subsequent kinetics of calcium carbonate precipitation were measured. The measurements included aqueous solutions and solutions in the presence of water miscible (ethylene glycol, MEG) and water immiscible organics (n-dodecane). All measurements were done at conditions of sustained supersaturation using the glass/ Ag/AgCl combination electrode as a probe of the precipitation and pH as the master variable for the addition of titrant solutions with appropriate concentration needed to maintenance the solution supersaturation. Initially, the metastable zone width was determined from measurements of the effect of the solution supersaturation on the induction time preceding the onset of precipitation at free-drift conditions. The

  10. Synthesis of finely divided molybdenum sulfide nanoparticles in propylene carbonate solution

    SciTech Connect

    Afanasiev, Pavel

    2014-05-01

    Molybdenum sulfide nanoparticles have been prepared from the reflux solution reaction involving ammonium heptamolybdate and elemental sulfur in propylene carbonate. Addition to the reaction mixture of starch as a natural capping agent leads to lesser agglomeration and smaller size of the particles. Nanoparticles of MoS{sub x} (x≈4) of 10–30 nm size are highly divided and form stable colloidal suspensions in organic solvents. Mo K edge EXAFS of the amorphous materials shows rapid exchange of oxygen to sulfur in the molybdenum coordination sphere during the solution reaction. Thermal treatment of the amorphous sulfides MoS{sub x} under nitrogen or hydrogen flow at 400 °C allows obtaining mesoporous MoS{sub 2} materials with very high pore volume and specific surface area, up to 0.45 cm{sup 3}/g and 190 m{sup 2}/g, respectively. The new materials show good potential for the application as unsupported hydrotreating catalysts. - Graphical abstract: Solution reaction in propylene carbonate allows preparing weakly agglomerated molybdenum sulfide with particle size 20 nm and advantageous catalytic properties. - Highlights: • Solution reaction in propylene carbonate yields MoS{sub x} particles near 20 nm size. • Addition of starch as capping agent reduces particles size and hinder agglomeration. • EXAFS at Mo K edge shows rapid oxygen to sulfur exchange in the solution. • Thermal treatment leads to MoS{sub 2} with very high porosity and surface area.

  11. Analyzing the kinetic response of tin oxide-carbon and tin oxide-CNT composites gas sensors for alcohols detection

    NASA Astrophysics Data System (ADS)

    Kamble, Vinayak; Umarji, Arun

    2015-03-01

    Tin oxide nanoparticles are synthesized using solution combustion technique and tin oxide - carbon composite thick films are fabricated with amorphous carbon as well as carbon nanotubes (CNTs). The x-ray diffraction, Raman spectroscopy and porosity measurements show that the as-synthesized nanoparticles are having rutile phase with average crystallite size ˜7 nm and ˜95 m2/g surface area. The difference between morphologies of the carbon doped and CNT doped SnO2 thick films, are characterized using scanning electron microscopy and transmission electron microscopy. The adsorption-desorption kinetics and transient response curves are analyzed using Langmuir isotherm curve fittings and modeled using power law of semiconductor gas sensors.

  12. Analyzing the kinetic response of tin oxide-carbon and tin oxide-CNT composites gas sensors for alcohols detection

    SciTech Connect

    Kamble, Vinayak Umarji, Arun

    2015-03-15

    Tin oxide nanoparticles are synthesized using solution combustion technique and tin oxide – carbon composite thick films are fabricated with amorphous carbon as well as carbon nanotubes (CNTs). The x-ray diffraction, Raman spectroscopy and porosity measurements show that the as-synthesized nanoparticles are having rutile phase with average crystallite size ∼7 nm and ∼95 m{sup 2}/g surface area. The difference between morphologies of the carbon doped and CNT doped SnO{sub 2} thick films, are characterized using scanning electron microscopy and transmission electron microscopy. The adsorption-desorption kinetics and transient response curves are analyzed using Langmuir isotherm curve fittings and modeled using power law of semiconductor gas sensors.

  13. Physical solubility of hydrogen sulfide and carbon dioxide in alkanolamine solutions

    SciTech Connect

    Abu-Arabi, M.K.

    1988-01-01

    The study was undertaken to develop a method that would make direct measurements of acid gases, hydrogen sulfide and carbon dioxide, physical solubilities in aqueous alkanolamine solutions possible. Hydrogen sulfide and carbon dioxide physical solubilities in 20, 35, and 50% by weight diethanolamine aqueous solutions were measured. The solubility measurements were made at acid gas partial pressure up to 1000 psia and temperatures of 80, 150, 240 F. The solubility of nitrous oxide in water and in protonated diethanolamine solution was also determined at 80 F. A method that allows for direct measurements of acid gases physical solubilities has been developed. The method eliminates amines reactivity with acid gases by protonating the amines prior to their contact with acid gases. CO{sub 2} physical solubility in aqueous DEA solutions occurs mainly in the water portion of the solution. Therefore, the physical solubility of CO{sub 2} in an aqueous amine solution must be corrected based on the fraction of water in the solution. However, H{sub 2}S physical solubility in aqueous DEA solutions is the same as H{sub 2}S solubility in water. At any acid gas partial pressure, the physical solubility of H{sub 2}S is higher than that of CO{sub 2} for the same solution concentration and for the same temperature. This is also true for their solubilities is pure water. The ratio of CO{sub 2} to H{sub 2}S physical solubility to N{sub 2}O solubility in aqueous DEA solutions is not the same as their ratio in pure water.

  14. Two-dimensional numerical simulation of the red blood cell floating in a plasma-alcohol solution through stenosis in a microvessel

    NASA Astrophysics Data System (ADS)

    Ni, Aleksey; Cheema, Taqi Ahmad; Kwak, Moon Kyu; Park, Cheol Woo

    2014-08-01

    A two-dimensional computational model of a single red blood cell (RBC) floating in a plasma-alcohol solution through a microchannel with stenosis was created using the Arbitrary Lagrangian-Eulerian (ALE) method with moving mesh for a fluid structure interaction problem. Cell deformability and stability were studied in a plasma-alcohol solution at different fluid flow conditions during movement through the channel with stenosis. Different results were obtained for different input parameters. Motion through 45% and 70% stenoses with the high and law velocities of the RBC and different viscosities was analyzed and successfully simulated. Results show that changes in RBC deformability were due to the effects of alcohol. Changes in behavior during motion were also observed. At low shear rate and high surrounding fluid viscosity the RBC showed a tendency to rotate during movement. The proposed model with its coupling of structural and fluid analysis techniques could be useful to understand the effect of alcohol on the RBC passing through stenosis.

  15. Performance evaluation of trimethylamine-carbon dioxide thermolytic draw solution for engineered osmosis

    SciTech Connect

    Boo, C; Khalil, YF; Elimelech, M

    2015-01-01

    We evaluated the performance of trimethylamine-carbon dioxide (TMA-CO2) as a potential thermolytic draw solution for engineered osmosis. Water flux and reverse solute flux with TMA-CO2 draw solution were measured in forward osmosis (FO) and pressure retarded osmosis (PRO) modes using thin-film composite (TFC) and cellulose triacetate (CTA) FO membranes. Water flux with the TMA-CO2 draw solution was comparable to that obtained with the more common ammonia-carbon dioxide (NH3-CO2) thermolytic draw solution at similar (1 M) concentration. Using a TFC-FO membrane, the water fluxes produced by 1 M TMA-CO2 and NH3-CO2 draw solutions with a DI water feed were, respectively, 33.4 and 35.6 L m(-2) h(-1) in PRO mode and 14.5 and 152 L m(-2) h(-1) in FO mode. Reverse draw permeation of TMA-CO2 was relatively low compared to NH3-CO2, ranging from 0.1 to 0.2 mol m(-2) h(-1) in all experiments, due to the larger molecular size of TMA. Thermal separation and recovery efficiency for TMA-CO2 was compared to NH3-CO2 by modeling low-temperature vacuum distillation utilizing low-grade heat sources. We also discuss possible challenges in the use TMA-CO2, including potential adverse impact on human health and environments. (C) 2014 Elsevier B.V. All rights reserved.

  16. Preparation of activated mesoporous carbons for electrosorption of ions from aqueous solutions

    SciTech Connect

    Dai, Sheng; Lee, Jeseung; Tsouris, Costas; DePaoli, David W; Wang, Xiqing

    2010-01-01

    Mesoporous carbon with a narrow pore size distribution centered at about 9 nm, which was prepared by self assembly of block copolymer and phloroglucinol-formaldehyde resin via the soft-template method, was activated by CO{sub 2} and potassium hydroxide (KOH). The effects of activation conditions, such as the temperature, activation time, and mass ratio of KOH/C, on the textural properties of the resulting activated mesoporous carbons were investigated. Activated mesoporous carbons exhibit high BET specific surface areas (up to {approx} 2000 m{sup 2} g{sup -1}) and large pore volumes (up to {approx} 1.6 cm{sup 3} g{sup -1}), but still maintain a highly mesoporous structure. Heat treatment of mesoporous carbons by CO{sub 2} generally requires a moderate to high extent of activation in order to increase its BET surface area by 2-3 times, while KOH activation needs a much smaller degree of activation than the former to reach an identical surface area, ensuring high yields of activated mesoporous carbons. In addition, KOH activation allows a controllable degree of activation by adjusting the mass ratio of KOH/C (2-8), as evidenced by the fact that surface area and pore volume increase with the mass ratio of KOH/C. The electrosorption properties of activated mesoporous carbons were investigated by cyclic voltammetry in 0.1 M NaCl aqueous solutions. Upon activation, the electrosorption capacitance of activated mesoporous carbons was greatly enhanced.

  17. Approximate Solutions for a Self-Folding Problem of Carbon Nanotubes

    SciTech Connect

    Y Mikata

    2006-08-22

    This paper treats approximate solutions for a self-folding problem of carbon nanotubes. It has been observed in the molecular dynamics calculations [1] that a carbon nanotube with a large aspect ratio can self-fold due to van der Waals force between the parts of the same carbon nanotube. The main issue in the self-folding problem is to determine the minimum threshold length of the carbon nanotube at which it becomes possible for the carbon nanotube to self-fold due to the van der Waals force. An approximate mathematical model based on the force method is constructed for the self-folding problem of carbon nanotubes, and it is solved exactly as an elastica problem using elliptic functions. Additionally, three other mathematical models are constructed based on the energy method. As a particular example, the lower and upper estimates for the critical threshold (minimum) length are determined based on both methods for the (5,5) armchair carbon nanotube.

  18. Electrochemical formation of hydroxide for enhancing carbon dioxide and acid gas uptake by a solution

    DOEpatents

    Rau, Gregory Hudson

    2014-07-01

    A system for forming metal hydroxide from a metal carbonate utilizes a water electrolysis cell having an acid-producing anode and a hydroxyl-producing cathode immersed in a water solution of sufficient ionic content to allow an electric current to pass between the hydroxyl-producing cathode and the acid-producing anode. A metal carbonate is placed in close proximity to the acid-producing anode. A direct current electrical voltage is provided across the acid-producing anode and the hydroxyl-producing cathode sufficient to generate acid at the acid-producing anode and hydroxyl ions at the hydroxyl-producing cathode. The acid dissolves at least part of the metal carbonate into metal and carbonate ions allowing the metal ions to travel toward the hydroxyl-producing cathode and to combine with the hydroxyl ions to form the metal hydroxide. The carbonate ions travel toward the acid-producing anode and form carbonic acid and/or water and carbon dioxide.

  19. Controls of carbonate mineralogy and solid-solution of Mg in calcite: evidence from spelean systems

    SciTech Connect

    Gonzalez, L.A.; Lohmann, K.C.

    1985-01-01

    Precipitation of carbonate minerals in spelean systems occurs under a wide range of fluid chemistry, Mg-Ca ratios, alkalinities, pH and temperatures; thus, spelean systems provide ideal settings to determine factors controlling the mineralogy of precipitated carbonates and solid-solution of Mg in calcite. Cave waters and actively-precipitating carbonate speleothems were collected from Carlsbad Caverns National Park, New Mexico and the Mammoth-Flint Cave System, Kentucky. Carbonate mineralogy of precipitated phases was determined by x-ray diffraction, and major and minor element composition of waters and accompanying minerals were determined by Atomic Absorption Spectrophotometry. Results demonstrate that at a constant CO3 concentration the precipitation threshold for calcite to aragonite is controlled dominantly by the Mg/Ca ratio of the ambient fluid. Aragonite precipitation is favored by high Mg/Ca ratios. Conversely, with increasing CO3 concentration at constant fluid Mg/Ca ratios, calcite is preferentially precipitated. Solid-solution of Mg in calcite is positively correlated with both increased Mg/Ca ratios and CO3 concentrations. These data suggest that Mg contents of calcite can not be defined solely in terms of a homogeneous distribution coefficient. Rather, Mg concentrations can be also be affected by the CO3 concentration and degree of calcite saturation, suggesting that the rate of crystal growth also plays and important role in Mg solid-solution in calcites.

  20. Iridium nanoparticles supported on hierarchical porous N-doped carbon: an efficient water-tolerant catalyst for bio-alcohol condensation in water

    NASA Astrophysics Data System (ADS)

    Liu, Di; Chen, Xiufang; Xu, Guoqiang; Guan, Jing; Cao, Quan; Dong, Bo; Qi, Yunfei; Li, Chunhu; Mu, Xindong

    2016-02-01

    Nitrogen-doped hierarchical porous carbons were synthesized successfully by a controllable one-pot method using glucose and dicyandiamide as carbon source and nitrogen source via hydrothermal carbonization process. The nitrogen-doped materials, possessing high nitrogen content (up to 7 wt%), large surface area (>320 m2 g-1) and excellent hierarchical nanostructure, were employed as catalyst supports for immobilization of iridium nanoparticles for bio-alcohol condensation in water. The introduction of nitrogen atoms into the carbon framework significantly improved iridium nanoparticles dispersion and stabilization. The novel iridium catalysts exhibited superior catalytic activity in the aqueous phase condensation of butanol, offering high butanol conversion of 45% with impressive 2-ethylhexanol selectivity of 97%. The heterogeneous catalysts had great advantages of easy recovery and high catalytic stability. The outstanding catalytic performance could be attributed to excellent dispersion of iridium nanoparticles, stronger iridium-support interactions and interaction of nitrogen species with alcohol substrates.

  1. Iridium nanoparticles supported on hierarchical porous N-doped carbon: an efficient water-tolerant catalyst for bio-alcohol condensation in water

    PubMed Central

    Liu, Di; Chen, Xiufang; Xu, Guoqiang; Guan, Jing; Cao, Quan; Dong, Bo; Qi, Yunfei; Li, Chunhu; Mu, Xindong

    2016-01-01

    Nitrogen-doped hierarchical porous carbons were synthesized successfully by a controllable one-pot method using glucose and dicyandiamide as carbon source and nitrogen source via hydrothermal carbonization process. The nitrogen-doped materials, possessing high nitrogen content (up to 7 wt%), large surface area (>320 m2 g−1) and excellent hierarchical nanostructure, were employed as catalyst supports for immobilization of iridium nanoparticles for bio-alcohol condensation in water. The introduction of nitrogen atoms into the carbon framework significantly improved iridium nanoparticles dispersion and stabilization. The novel iridium catalysts exhibited superior catalytic activity in the aqueous phase condensation of butanol, offering high butanol conversion of 45% with impressive 2-ethylhexanol selectivity of 97%. The heterogeneous catalysts had great advantages of easy recovery and high catalytic stability. The outstanding catalytic performance could be attributed to excellent dispersion of iridium nanoparticles, stronger iridium-support interactions and interaction of nitrogen species with alcohol substrates. PMID:26912370

  2. Removal of Heavy Metal Ions and Diethylenetriamine Species from Solutions by Magnetic Activated Carbon

    NASA Astrophysics Data System (ADS)

    Liu, Kaiwen

    Even though activated carbon is widely used in the removal of contaminants from effluents, it is difficult to be completely recovered by screening or classification. In this project, we prepared a magnetic form of activated carbon (M-AC) by co-precipitation of iron oxides onto activated carbon surface. M-AC can be separated from solutions by applying an external magnetic field and regenerated for reuse. The synthesized M-AC was characterized by X-ray diffraction, specific surface area measurement, and scanning electron microscope. Characterization results show that the major phase of coated iron oxides is magnetite (Fe 3O4). Batch adsorption experiments were carried out for single-component and multi-component solutions. M-AC shows a better adsorption capacity for singlecomponent of Cu (II), Ni (II), or diethylenetriamine (DETA) and for multiple-components of Cu-DETA and Ni-DETA complexes in deionized water than activated carbon. M-AC also shows the potential application in carbon-in-pulp process for gold recovery.

  3. a Search for Interstellar Carbon-Chain Alcohol HC4OH in the Star Forming Region L1527

    NASA Astrophysics Data System (ADS)

    Araki, Mitsunori; Takano, Shuro; Koshikawa, Hiromichi Yamabe Naohiro; Tsukiyama, Koichi; Nakane, Aya; Okabatyashi, Toshiaki; Kunimatsu, Arisa; Kuze, Nobuhiko

    2011-06-01

    We have made a sensitive search for the rotational transitions of carbon-chain alcohol HC_4OH with the frequency ragne from 21.2 to 46.7 GHz in the star forming region L1527 in Taurus with rich carbon-chain chemistry. The incentive of this observation was a laboratory detection of HC_4OH by the microwave spectroscopy. Despite achieving an rms of several mK in antenna temperature by the 45m telescope at Nobeyama Radio Observatory, the searche for HC_4OH was negative, leading to a 5 sigma upper limit corresponding to the column density of 4 × 1012 Cm-2 based on the excitation temperature of 12.3 K. The upper limit indicates that the [HC_4-OH]/[HC_4-CN] ratio is less than 1.0. The ratio suggests that the cyanide species with carbon-chain structure is dominant in comparison with the hydroxyl one in L1527, which can be the opposite case of saturated compounds, e.g. CH_3OH and CH_3CN, in hot cores and dark clouds.

  4. Bending and Twisting of Suspended Single-Walled Carbon Nanotubes in Solution

    NASA Astrophysics Data System (ADS)

    Barnard, Arthur; Xu, Ya-Qiong; McEuen, Paul

    2010-03-01

    We combine suspended, aligned carbon nanotube transistors with optical trapping techniques and scanning photocurrent microscopy to investigate the mechanics of suspended single-walled carbon nanotubes as well as DNA-nanotube systems in solution. We study the movement of nanotubes by monitoring their photocurrent images and measure their thermal fluctuations by imaging microbeads that are tightly attached to nanotubes by single-stranded DNA. By analyzing thermal fluctuations of these microbeads and by using optical tweezers we are able to obtain the torsional and bending stiffness of nanotubes and then calculate their diameters. We can also measure, with subangstrom resolution, the effective attachment point of the microbead to the nanotube.

  5. Beyond temperature: Clumped isotope signatures in dissolved inorganic carbon species and the influence of solution chemistry on carbonate mineral composition

    NASA Astrophysics Data System (ADS)

    Tripati, Aradhna K.; Hill, Pamela S.; Eagle, Robert A.; Mosenfelder, Jed L.; Tang, Jianwu; Schauble, Edwin A.; Eiler, John M.; Zeebe, Richard E.; Uchikawa, Joji; Coplen, Tyler B.; Ries, Justin B.; Henry, Drew

    2015-10-01

    "Clumped-isotope" thermometry is an emerging tool to probe the temperature history of surface and subsurface environments based on measurements of the proportion of 13C and 18O isotopes bound to each other within carbonate minerals in 13C18O16O22- groups (heavy isotope "clumps"). Although most clumped isotope geothermometry implicitly presumes carbonate crystals have attained lattice equilibrium (i.e., thermodynamic equilibrium for a mineral, which is independent of solution chemistry), several factors other than temperature, including dissolved inorganic carbon (DIC) speciation may influence mineral isotopic signatures. Therefore we used a combination of approaches to understand the potential influence of different variables on the clumped isotope (and oxygen isotope) composition of minerals. We conducted witherite precipitation experiments at a single temperature and at varied pH to empirically determine 13C-18O bond ordering (Δ47) and δ18O of CO32- and HCO3- molecules at a 25 °C equilibrium. Ab initio cluster models based on density functional theory were used to predict equilibrium 13C-18O bond abundances and δ18O of different DIC species and minerals as a function of temperature. Experiments and theory indicate Δ47 and δ18O compositions of CO32- and HCO3- ions are significantly different from each other. Experiments constrain the Δ47-δ18O slope for a pH effect (0.011 ± 0.001; 12 ⩾ pH ⩾ 7). Rapidly-growing temperate corals exhibit disequilibrium mineral isotopic signatures with a Δ47-δ18O slope of 0.011 ± 0.003, consistent with a pH effect. Our theoretical calculations for carbonate minerals indicate equilibrium lattice calcite values for Δ47 and δ18O are intermediate between HCO3- and CO32-. We analyzed synthetic calcites grown at temperatures ranging from 0.5 to 50 °C with and without the enzyme carbonic anhydrase present. This enzyme catalyzes oxygen isotopic exchange between DIC species and is present in many natural systems. The two

  6. Removal of polychlorinated biphenyls from aqueous solutions using beta-cyclodextrin grafted multiwalled carbon nanotubes.

    PubMed

    Shao, Dadong; Sheng, Guodong; Chen, Changlun; Wang, Xiangke; Nagatsu, Masaaki

    2010-04-01

    Cyclodextrins have excellent ability in the preconcentration of organic pollutants from aqueous solutions by forming inclusion complexes. Multiwalled carbon nanotubes (MWCNTs) possess high adsorption capacity in the removal of organic pollutants through the formation of conjugated complexes. In this paper, beta-cyclodextrin (beta-CD) was grafted on the surfaces of MWCNTs by using plasma technique. The beta-CD grafted MWCNTs (MWCNT-g-CD) were characterized by using Raman spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, thermo gravimetric analysis-differential thermal analysis, and scanning electron microscopy in detail. The prepared MWCNT-g-CD were used to remove polychlorinated biphenyls (PCBs) from aqueous solutions under ambient conditions. The results suggest that MWCNT-g-CD have much higher adsorption capacity than MWCNTs in the removal of PCBs from aqueous solutions. MWCNT-g-CD are suitable materials in the preconcentration and immobilization of PCBs from large volumes of aqueous solutions in environmental pollution cleanup.

  7. [Dissolved aluminum and organic carbon in soil solution under six tree stands in Lushan forest ecosystems].

    PubMed

    Wang, Lianfeng; Pan, Genxing; Shi, Shengli; Zhang, Lehua; Huang, Mingxing

    2003-10-01

    Different depths of soils under 6 tree stands in Lushan Botany Garden were sampled and water-digested at room temperature. The dissolved aluminum and organic carbon were then determined by colorimetry, using 8-hydroxylquilin and TOC Analyzer, respectively. The results indicated that even derived from a naturally identical soil type, the test soils exhibited a diverse solution chemistry, regarding with the Al speciation. The soil solutions under Japanese cedar, giant arborvitae and tea had lower pH values and higher contents of soluble aluminum than those under Giant dogwood, azalea and bamboo. Under giant arborvitae, the lowest pH and the highest content of total soluble aluminum and monomeric aluminum were found in soil solution. There was a significant correlation between soluble aluminum and DOC, which tended to depress the accumulation of toxic monomeric aluminum. The 6 tree stands could be grouped into 2 categories of solution chemistry, according to aluminum mobilization.

  8. Convenient immobilization of Pt-Sn bimetallic catalysts on nitrogen-doped carbon nanotubes for direct alcohol electrocatalytic oxidation.

    PubMed

    Wang, Xizhang; Xue, Hua; Yang, Lijun; Wang, Huakai; Zang, Pengyuan; Qin, Xintai; Wang, Yangnian; Ma, Yanwen; Wu, Qiang; Hu, Zheng

    2011-09-30

    Pt-Sn alloy nanoparticles were conveniently immobilized on nitrogen-doped carbon nanotubes (NCNTs) through microwave-assisted ethylene glycol reduction. The nanoparticles have a narrow particle size distribution with the average particle size around 3 nm as measured by transmission electron microscopy and x-ray diffraction. The binding energy of metallic Sn passively shifts due to the charge transfer from Sn to Pt, as revealed by x-ray photoelectron spectroscopy. In comparison with the commercial Pt/C catalyst, Pt/NCNT presents a clear increase in activity for alcohol electro-oxidation due to the improved support, while the bimetallic Pt-Sn/NCNT has even higher activity owing to the alloying of Pt with Sn. Both Pt-Sn/NCNT and Pt/NCNT catalysts exhibit competitive long-term stability to Pt/C catalyst. The low cost, simple preparation and superior electrocatalytic performance indicate the great potential of Pt-Sn/NCNT in direct alcohol fuel cells.

  9. Bimetallic CuCo nanoparticles derived from hydrotalcite supported on carbon fibers for higher alcohols synthesis from syngas

    NASA Astrophysics Data System (ADS)

    Wang, Lianfang; Cao, Ang; Liu, Guilong; Zhang, Lihong; Liu, Yuan

    2016-01-01

    Higher alcohols synthesis (HAS) is a strong exothermal reaction which leads to the formation of hotspots on the catalysts and the hotspots result in poor selectivity, and Cu-Co based catalysts are one of the most promising to which the formation of Cu-Co alloy is critical. Therefore a new scheme was proposed, based on the excellent thermal conductivity of carbon fibers (CFs) and the uniform mixing of metal ions in layered double hydroxides (LDHs), the latter favors the formation of metallic alloy. Nanocomposites of LDHs and CFs were prepared by using co-precipitation method and used for HAS, and characterized by using FTIR, N2 adsorption-desorption, XRD, TPR, SEM and TEM techniques. In the composites, nanosheets with the typical LDHs morphology are perpendicularly grown on the surface of CFs while intersecting each other, creating a highly open and porous structure. After reduction, Cu-Co-alloy nanoparticles are formed from the LDHs. The resultant catalysts showed high activity and much high selectivity to higher alcohols. The reported methods can be expanded to prepare other LDHs/CFs composites.

  10. Expression of testosterone-dependent enzyme, carbonic anhydrase III, and oxidative stress in experimental alcoholic liver disease.

    PubMed

    Parkkila, S; Halsted, C H; Villanueva, J A; Väänänen, H K; Niemelä, O

    1999-11-01

    We studied the sequential immunohistochemical appearance of androgen-dependent carbonic anhydrase (CA III) during the development of ethanol-induced liver injury using liver samples from castrated and noncastrated male micropigs. In castrated micropigs, the baseline expression of CA III was either low or absent, while distinct positive immunoreactions were found in zone 3 hepatocytes at 5 and 12 months after the initiation of the ethanol diet. The CA III enzyme and protein adducts of lipid peroxidation-derived aldehydic products, malondialdehyde and 4-hydroxynonenal, appeared together in the perivenous region, suggesting that the enzyme functions in an oxidative environment. The positive staining became more abundant and widespread during the progression of alcoholic liver disease. After 12 months, CA III was significantly more abundant in both the ethanol-fed noncastrated and castrated micropigs than in the control animals (P < 0.001, P < 0.05, respectively). CA III content was strikingly high in the ethanol-fed noncastrated animals, consistent with a potential role of androgens in the regulation of ethanol-induced CA III expression. The strongly positive CA III immunoreactions in the ethanol-fed noncastrated micropigs were associated with scant evidence of aldehydic protein adducts and minimal histopathology. Thus, enhanced expression of CA III during ethanol consumption may also account in part for gender differences in the susceptibility for alcohol-induced liver injury.

  11. Conversion of a metal-organic framework to N-doped porous carbon incorporating Co and CoO nanoparticles: direct oxidation of alcohols to esters.

    PubMed

    Zhou, Yu-Xiao; Chen, Yu-Zhen; Cao, Lina; Lu, Junling; Jiang, Hai-Long

    2015-05-14

    A Co-based metal-organic framework, ZIF-67, has been exploited as a self-template to afford N-doped porous carbon incorporating Co NPs with surface-oxidized CoO species, which exhibit excellent catalytic activity, selectivity and magnetic recyclability toward the direct oxidation of alcohols to esters with O2 as a benign oxidant under mild conditions.

  12. Environmentally benign formation of polymeric microspheres by rapid expansion of supercritical carbon dioxide solution with a nonsolvent.

    PubMed

    Matsuyama, K; Mishima, K; Umemoto, H; Yamaguchi, S

    2001-10-15

    A novel method is reported for forming polymer microparticles, which reduce atmospheric emissions of environmentally harmful volatile organic compounds such as toluene and xylene used as paint solvent in paint industry. The polymer microparticles have formed through rapid expansion from supercritical solution with a nonsolvent (RESS-N). Solubilization of poly(styrene)-b-(poly(methyl methacrylate)-co-poly (glycidyl methacrylate)) copolymer(PS-b-(PMMA-co-PGMA), MW = 5000, PS/PMMA/PGMA = 2/5/3), poly(ethylene glycol) (PEG, M. W = 4000), bisphenol A type epoxy resin (EP, MW = 3000), poly(methyl methacrylate) (PMMA; MW = 15000, 75000, 120000), and poly(oxyalkylene) alkylphenyl ether (MW = 4000) in carbon dioxide (CO2) was achieved with the use of small alcohols as cosolvents. The solubility of the PS-b-(PMMA-co-PGMA) is extremely low in either CO2 or ethanol but becomes 20 wt % in a mixture of the two. Because ethanol is a nonsolvent for the polymer, it can be used as a cosolvent in rapid expansion from supercritical solution to produce 1-3 microm particles that do not agglomerate. Obtained polymer particles by RESS-N were applied as powder coatings. The resulting coatings have a smooth and coherent film. The particle size distribution of microspheres was controlled by changing the polymer concentration, preexpansion pressure, temperature, and injection distance. The feed compositions were more effective than the other factors in controlling the particle size. The polymeric microparticles formed by RESS-N method can be utilized to make the thin coating film without anytoxic organic solvents and/or surfactants. PMID:11686380

  13. Experimental study of the behavior of molybdenum in hot sulfide-carbonate solutions

    SciTech Connect

    Agapova, G.F.; Shmariovich, E.M.; Vorob'ev, I.M.; Khitarov, D.N.

    1987-04-01

    Previous experiments have characterized the behavior of uranium in sulfide-carbonate solutions at 200/sup 0/C, analogous to the solutions that produced many endogenous pitchblende deposits, as indicated by fluid inclusions in minerals and by mineralogical and geochemical data. Molybdenum often accompanies uranium in endogenous pitchblende and related deposits and may form economic accumulations as low-temperature molybdenite. There have been repeated discussions on the forms taken by molybdenum and the reasons for deposition in such ores. The experiments described here indicate the existence of various complexes of molybdenum under different conditions and explain some of the paragenesis of molybdenum minerals with uranium minerals. 12 references, 3 figures, 1 table.

  14. Electro-adsorption of tetracycline from aqueous solution by carbonized pomelo peel and composite with aniline

    NASA Astrophysics Data System (ADS)

    Li, Na; Yang, Shaogui; Chen, Jian; Gao, Jia; He, Huan; Sun, Cheng

    2016-11-01

    Tetracycline is an important broad-spectrum antibiotic. Its overuse can easily cause water and soil pollution. In this study, a carbon electrode was successfully prepared by simple carbonization of a natural material pomelo peel to remove tetracycline from aqueous solution through electro-adsorption. Then the carbon electrode was modified by aniline to improve its mechanical strength. These materials were characterized by XRD, SEM, FT-IR and Zeta Potential, and all these characterizations demonstrated aniline coated on the carbon electrode perfectly. CV tests of electrodes demonstrated that carbon electrode was more inclined to the double layer capacitance, and composite electrode exhibited more properties of the pseudo capacitance. Adsorption experiments showed that adsorption efficiency of the carbon electrode was 95.11% after 3000 s and that of the composite electrode was 92.32% after 5000 s; polyaniline greatly improved the mechanical stability of the composite electrode. The composite electrode with high adsorbability and strong mechanical stability, has potential to treat tetracycline-containing wastewaters.

  15. Static and dynamic adsorption of phenol from aqueous solution using spherical carbon

    NASA Astrophysics Data System (ADS)

    Bhargavi, R.; Kadirvelu, K.; Kumar, N. S.

    2013-06-01

    The objective of this work is to evaluate spherical carbon and modified spherical carbon for the removal of phenol from aqueous solution in static and dynamic studies under various conditions. It explores mainly two adsorbents, that is, activated spherical carbon (ASC) and modified activated spherical carbon (SSC). SEM characterization of both the adsorbents showed a clear change in the physical and chemical properties of the modified adsorbent from its precursor activated carbon. Both the adsorbents are subjected to static mode adsorption studies and after a comparison based on isotherm analysis; more efficient adsorbent is screened for column mode adsorption studies. The phenol removal increased for modified carbon. The aim of carrying out column mode studies will aid in ascertaining the practical applicability of the adsorbent in the real system and therefore, to assess the effect of various process variables, viz., bed height of the adsorbent, flow rate and initial concentration of the adsorbate on breakthrough time and adsorption capacity. The column studies generated data were modeled using the empirical relationship based on Bohart-Adams model. At the end, the option of regenerating the adsorbent was also explored using sodium hydroxide with the aim of minimize the hazardous generated and also to reuse the adsorbent material for many cycles without affecting original properties. Adsorbent regeneration efficiency of 72% was achieved. This investigation reveals that the material used as an adsorbent is very effective with high adsorption capacities and also possible to use in the real contaminated system.

  16. Role of single-walled carbon nanotubes on ester hydrolysis and topography of electrospun bovine serum albumin/poly(vinyl alcohol) membranes.

    PubMed

    Ford, Ericka N J; Suthiwangcharoen, Nisaraporn; D'Angelo, Paola A; Nagarajan, Ramanathan

    2014-07-23

    Electrospun membranes were studied for the chemical deactivation of threat agents by means of enzymatic proteins. Protein loading and the surface chemistry of hybrid nanofibers influenced the efficacy by which embedded enzymes could digest the substrate of interest. Bovine serum albumin (BSA), selected as a model protein, was electrospun into biologically active fibers of poly(vinyl alcohol), PVA. Single-walled carbon nanotubes (SWNTs) were blended within these mixtures to promote protein assembly during the process of electrospinning and subsequently the ester hydrolysis of the substrates. The SWNT incorporation was shown to influence the topography of PVA/BSA nanofibers and enzymatic activity against paraoxon, a simulant for organophosphate agents and a phosphorus analogue of p-nitrophenyl acetate (PNA). The esterase activity of BSA against PNA was uncompromised upon its inclusion within nanofibrous membranes because similar amounts of PNA were hydrolyzed by BSA in solution and the electrospun BSA. However, the availability of BSA along the fiber surface was shown to affect the ester hydrolysis of paraoxon. Atomic force microscopy images of nanofibers implicated the surface migration of BSA during the electrospinning of SWNT filled dispersions, especially as greater weight fractions of protein were added to the spinning mixtures. In turn, the PVA/SWNT/BSA nanofibers outperformed the nanotube free PVA/BSA membranes in terms of paraoxon digestion. The results support the development of electrospun polymer nanofiber platforms, modulated by SWNTs for enzyme catalytic applications relevant to soldier protective ensembles. PMID:25007411

  17. Passive approach for the improved dispersion of polyvinyl alcohol-based functionalized multi-walled carbon nanotubes/Nafion membranes for polymer electrolyte membrane fuel cells.

    PubMed

    Abu Sayeed, M D; Talukdar, Krishan; Kim, Hee Jin; Park, Younjin; Gopalan, A I; Kim, Young Ho; Lee, Kwang-Pill; Choi, Sang-June

    2014-12-01

    Multi-walled carbon nanotubes (MWCNTs) are regarded as ideal fillers for Nafion polymer electrolyte membranes (PEMs) for fuel cell applications. The highly aggregated properties of MWCNTs can be overcome by the successful cross-linking with polyvinyl alcohol (PVA) into the MWCNTs/Nafion membrane. In this study, a series of nanocomposite membranes were fabricated with the PVA-influenced functionalized MWCNTs reinforced into the Nafion polymer matrix by a solution casting method. Several different PVA contents were blended to f-MWCNTs/Nafion nanocomposite membranes followed by successful cross-linking by annealing. The surface morphologies and the inner structures of the resulting PVA-MWCNTs/Nafion nanocomposite membranes were then observed by optical microscopy and scanning electron microscopy (SEM) to investigate the dispersion of MWCNTs into the PVA/Nafion composite membranes. After that, the nanocomposite membranes were characterized by thermo-gravimetric analysis (TGA) to observe the thermal enhancement caused by effective cross-linking between the f-MWCNTs with the composite polymer matrixes. Improved water uptake with reduced methanol uptake revealed the successful fabrication of PVA-blended f-MWCNTs/Nafion membranes. In addition, the ion exchange capacity (IEC) was evaluated for PEM fuel cell (PEMFC) applications.

  18. Influence of the nature of the alcohol on the principles of the photocatalytic liberation of hydrogen from aqueous-organic solutions of europium salts

    SciTech Connect

    Myakon'kii, A.G.; Rozenkevich, M.B.; Potapova, G.V.

    1988-09-01

    The process of photocatalytic liberation of hydrogen from aqueous alcohol (ROH - CH/sub 3/OH, C/sub 2/H/sub 5/OH, C/sub 3/H/sub 7/OH, iso-C/sub 3/H/sub 7/OH) solutions of europium salts was investigated. In solutions containing sodium formate as a second organic component, HCOONa and ROH take part in the photoreduction of Eu(III), whereas the main role in the photooxidation of Eu(II) is played by ROH molecules. Such behavior of the system is explained by transfer of an electron in these reactions according to outer- and inner-sphere mechanism, respectively.

  19. Removal of insecticide carbofuran from aqueous solutions by banana stalks activated carbon.

    PubMed

    Salman, J M; Hameed, B H

    2010-04-15

    In this work, activated carbon was prepared from banana stalks (BSAC) waste to remove the insecticide carbofuran from aqueous solutions. The effects of contact time, initial carbofuran concentration, solution pH and temperature (30, 40 and 50 degrees C) were investigated. Adsorption isotherm, kinetics and thermodynamics of carbofuran on BSAC were studied. Equilibrium data were fitted to the Langmuir, Freundlich and Temkin isotherm models and the data best represented by the Langmuir isotherm. Thermodynamic parameters such as standard enthalpy (DeltaH(o)), standard entropy (DeltaS(o)) and standard free energy (DeltaG(o)) were evaluated. Regeneration efficiency of spent BSAC was studied using ethanol as a solvent. The efficiency was found to be in the range of 96.97-97.35%. The results indicated that the BSAC has good regeneration and reusability characteristics and can be used as alternative to present commercial activated carbon.

  20. Removal of Cr(VI) from aqueous solution by adsorption onto activated carbon.

    PubMed

    Selvi, K; Pattabhi, S; Kadirvelu, K

    2001-10-01

    Activated carbon (AC) prepared from coconut tree sawdust was used as an adsorbent for the removal of Cr(VI) from aqueous solution. Batch mode adsorption studies were carried out by varying agitation time, initial Cr(VI) concentration, carbon concentration and pH. Langmuir and Freundlich adsorption isotherms were applied to model the adsorption data. Adsorption capacity was calculated from the Langmuir isotherm and was 3.46 mg/g at an initial pH of 3.0 for the particle size 125-250 microm. The adsorption of Cr(VI) was pH dependent and maximum removal was observed in the acidic pH range. Desorption studies were carried out using 0.01-1 M NaOH solutions.

  1. A palladium-doped ceria@carbon core-sheath nanowire network: a promising catalyst support for alcohol electrooxidation reactions

    NASA Astrophysics Data System (ADS)

    Tan, Qiang; Du, Chunyu; Sun, Yongrong; Du, Lei; Yin, Geping; Gao, Yunzhi

    2015-08-01

    A novel palladium-doped ceria and carbon core-sheath nanowire network (Pd-CeO2@C CSNWN) is synthesized by a template-free and surfactant-free solvothermal process, followed by high temperature carbonization. This hierarchical network serves as a new class of catalyst support to enhance the activity and durability of noble metal catalysts for alcohol oxidation reactions. Its supported Pd nanoparticles, Pd/(Pd-CeO2@C CSNWN), exhibit >9 fold increase in activity toward the ethanol oxidation over the state-of-the-art Pd/C catalyst, which is the highest among the reported Pd systems. Moreover, stability tests show a virtually unchanged activity after 1000 cycles. The high activity is mainly attributed to the superior oxygen-species releasing capability of Pd-doped CeO2 nanowires by accelerating the removal of the poisoning intermediate. The unique interconnected one-dimensional core-sheath structure is revealed to facilitate immobilization of the metal catalysts, leading to the improved durability. This core-sheath nanowire network opens up a new strategy for catalyst performance optimization for next-generation fuel cells.A novel palladium-doped ceria and carbon core-sheath nanowire network (Pd-CeO2@C CSNWN) is synthesized by a template-free and surfactant-free solvothermal process, followed by high temperature carbonization. This hierarchical network serves as a new class of catalyst support to enhance the activity and durability of noble metal catalysts for alcohol oxidation reactions. Its supported Pd nanoparticles, Pd/(Pd-CeO2@C CSNWN), exhibit >9 fold increase in activity toward the ethanol oxidation over the state-of-the-art Pd/C catalyst, which is the highest among the reported Pd systems. Moreover, stability tests show a virtually unchanged activity after 1000 cycles. The high activity is mainly attributed to the superior oxygen-species releasing capability of Pd-doped CeO2 nanowires by accelerating the removal of the poisoning intermediate. The unique

  2. Changing fluxes of carbon and other solutes from the Mekong River

    PubMed Central

    Li, Siyue; Bush, Richard T.

    2015-01-01

    Rivers are an important aquatic conduit that connects terrestrial sources of dissolved inorganic carbon (DIC) and other elements with oceanic reservoirs. The Mekong River, one of the world’s largest rivers, is firstly examined to explore inter-annual fluxes of dissolved and particulate constituents during 1923–2011 and their associated natural or anthropogenic controls. Over this period, inter-annual fluxes of dissolved and particulate constituents decrease, while anthropogenic activities have doubled the relative abundance of SO42−, Cl− and Na+. The estimated fluxes of solutes from the Mekong decrease as follows (Mt/y): TDS (40.4) > HCO3− (23.4) > Ca2+ (6.4) > SO42− (3.8) > Cl− (1.74)~Na+ (1.7) ~ Si (1.67) > Mg2+ (1.2) > K+ (0.5). The runoff, land cover and lithological composition significantly contribute to dissolved and particulate yields globally. HCO3− and TDS yields are readily predicted by runoff and percent of carbonate, while TSS yield by runoff and population density. The Himalayan Rivers, including the Mekong, are a disproportionally high contributor to global riverine carbon and other solute budgets, and are of course underlined. The estimated global riverine HCO3− flux (Himalayan Rivers included) is 34014 × 109 mol/y (0.41 Pg C/y), 3915 Mt/y for solute load, including HCO3−, and 13553 Mt/y for TSS. Thereby this study illustrates the importance of riverine solute delivery in global carbon cycling. PMID:26522820

  3. Electrochemical studies of the film formation on lithium in propylene carbonate solutions under open circuit conditions

    SciTech Connect

    Geronov, Y.; Schwager, F.; Muller, R.H.

    1981-04-01

    The nature of protective surface layers formed on lithium in propylene carbonate solutions of LiClO/sub 4/ and LiAsF/sub 6/ at open circuit has been investigated by electrochemical pulse measurements and other techniques. The results are consistent with the fast formation of a compact thin layer of Li/sub 2/O by reaction with residual water. This layer acts as a solid ionic conductor. Slow corrosion processes produce a thicker porous overlayer.

  4. Method for producing hydrocarbon and alcohol mixtures. [Patent application

    DOEpatents

    Compere, A.L.; Googin, J.M.; Griffith, W.L.

    1980-12-01

    It is an object of this invention to provide an efficient process for extracting alcohols and ketones from an aqueous solution containing the same into hydrocarbon fuel mixtures, such as gasoline, diesel fuel and fuel oil. Another object of the invention is to provide a mixture consisting of hydrocarbon, alcohols or ketones, polyoxyalkylene polymer and water which can be directly added to fuels or further purified. The above stated objects are achieved in accordance with a preferred embodiment of the invention by contacting an aqueous fermentation liquor with a hydrocarbon or hydrocarbon mixture containing carbon compounds having 5 to 18 carbon atoms, which may include gasoline, diesel fuel or fuel oil. The hydrocarbon-aqueous alcohol solution is mixed in the presence or one or more of a group of polyoxyalkylene polymers described in detail hereinafter; the fermentation alcohol being extracted into the hydrocarbon fuel-polyoxyalkylene polymer mixture.

  5. Nanofiltration of Electrolyte Solutions by Sub-2nm Carbon Nanotube Membranes

    SciTech Connect

    Fornasiero, F; Park, H G; Holt, J K; Stadermann, M; Kim, S; In, J B; Grigoropoulos, C P; Noy, A; Bakajin, O

    2008-03-13

    Both MD simulations and experimental studies have shown that liquid and gas flow through carbon nanotubes with nanometer size diameter is exceptionally fast. For applications in separation technology, selectivity is required together with fast flow. In this work, we use pressure-driven filtration experiments to study ion exclusion in silicon nitride/sub-2-nm CNT composite membranes as a function of solution ionic strength, pH, and ion valence. We show that carbon nanotube membranes exhibit significant ion exclusion at low salt concentration. Our results support a rejection mechanism dominated by electrostatic interactions between fixed membrane charges and mobile ions, while steric and hydrodynamic effects appear to be less important. Comparison with commercial nanofiltration membranes for water softening reveals that our carbon nanotube membranes provides far superior water fluxes for similar ion rejection capabilities.

  6. InP synthesis by the synthesis, solute diffusion (SSD) method using glassy-carbon crucibles

    SciTech Connect

    Miskys, C.R.; Oliveira, C.E.M. de; Carvalho, M.M.G. de

    1996-12-31

    An Indium Phosphide (InP) Synthesis system by the Synthesis, Solute Diffusion (SSD) method has been built. It provides high purity InP charges with low carrier densities (3 {times} 10{sup 14} to 2 {times} 10{sup 15} cm{sup {minus}3}) to be used as starting material for InP single-crystal Liquid Encapsulated Czochralski (LEC) growth. Glassy-carbon is a refractory material with low vapor pressure that can be moulded in various forms and sizes. Indeed the glassy-carbon crucible is reusable after the synthesis because InP does not stick to its walls. Preliminary electrical characteristics measurements showed residual carrier concentration below 3 {times} 10{sup 15} cm{sup {minus}3}. These results are comparable with those achieved utilizing quartz crucibles. The features denoted makes glassy-carbon an interesting alternative in comparison with quartz and PBN crucibles.

  7. Shear-induced structure evolution of carbon nanotubes dispersions in polyacrylonitrile-dimethylsulfoxide solution

    NASA Astrophysics Data System (ADS)

    Karpushkin, Evgeny; Lapshina, Maria; Sergeyev, Vladimir

    2015-04-01

    Rheological behavior of carbon nanotubes finely dispersed in polyacrylonitrile-dimethylsulfoxide solution has been studied as function of the applied pre-shear stress and discussed in view of possible structural changes induced by the pre-shearing of the samples. The observed effects can be ascribed to a combination of internal processes involving alignment and association of the macromolecules as well as orientation and association of carbon nanotubes. The effects caused by the macromolecules alignment and association are mainly observed at low concentration of the filler and at higher shear stress, whereas the processes involving carbon nanotubes reorganization are mainly observed at the higher filler content and at low pre-shear stress.

  8. Adsorption of bisphenol-A from aqueous solution onto minerals and carbon adsorbents.

    PubMed

    Tsai, Wen-Tien; Lai, Chi-Wei; Su, Ting-Yi

    2006-06-30

    The adsorption behaviors of bisphenol-A, which has been listed as one of endocrine disrupting chemicals, from aqueous solution onto four minerals including andesite, diatomaceous earth, titanium dioxide, and activated bleaching earth, and two activated carbons with coconut-based and coal-based virgins were examined in this work. Based on the adsorption results at the specified conditions, the adsorption capacities of activated carbons are significantly larger than those of mineral adsorbents, implying that the former is effective for removal of the highly hydrophobic adsorbate from the aqueous solution because of its high surface area and low surface polarity. The adsorption capacities of bisphenol-A onto these mineral adsorbents with different pore properties are almost similar in magnitude mainly due to the weakly electrostatic interaction between the mineral surface with negative charge and the target adsorbate with hydrophobic nature. Further, a simplified kinetic model, pseudo-second-order, was tested to investigate the adsorption behaviors of bisphenol-A onto the two common activated carbons at different solution conditions. It was found that the adsorption process could be well described with the pseudo-second-order model. The kinetic parameters of the model obtained in the present work are in line with the pore properties of the two adsorbents.

  9. Adsorption of bisphenol-A from aqueous solution onto minerals and carbon adsorbents.

    PubMed

    Tsai, Wen-Tien; Lai, Chi-Wei; Su, Ting-Yi

    2006-06-30

    The adsorption behaviors of bisphenol-A, which has been listed as one of endocrine disrupting chemicals, from aqueous solution onto four minerals including andesite, diatomaceous earth, titanium dioxide, and activated bleaching earth, and two activated carbons with coconut-based and coal-based virgins were examined in this work. Based on the adsorption results at the specified conditions, the adsorption capacities of activated carbons are significantly larger than those of mineral adsorbents, implying that the former is effective for removal of the highly hydrophobic adsorbate from the aqueous solution because of its high surface area and low surface polarity. The adsorption capacities of bisphenol-A onto these mineral adsorbents with different pore properties are almost similar in magnitude mainly due to the weakly electrostatic interaction between the mineral surface with negative charge and the target adsorbate with hydrophobic nature. Further, a simplified kinetic model, pseudo-second-order, was tested to investigate the adsorption behaviors of bisphenol-A onto the two common activated carbons at different solution conditions. It was found that the adsorption process could be well described with the pseudo-second-order model. The kinetic parameters of the model obtained in the present work are in line with the pore properties of the two adsorbents. PMID:16343748

  10. Removal of organic contaminants from aqueous solution by cattle manure compost (CMC) derived activated carbons

    NASA Astrophysics Data System (ADS)

    Qian, Qingrong; Chen, Qinghua; Machida, Motoi; Tatsumoto, Hideki; Mochidzuki, Kazuhiro; Sakoda, Akiyoshi

    2009-04-01

    The activated carbons (ACs) prepared from cattle manure compost (CMC) with various pore structure and surface chemistry were used to remove phenol and methylene blue (MB) from aqueous solutions. The adsorption equilibrium and kinetics of two organic contaminants onto the ACs were investigated and the schematic models for the adsorptive processes were proposed. The result shows that the removal of functional groups from ACs surface leads to decreasing both rate constants for phenol and MB adsorption. It also causes the decrement of MB adsorption capacity. However, the decrease of surface functional groups was found to result in the increase of phenol adsorption capacity. In our schematic model for adsorptive processes, the presence of acidic functional groups on the surface of carbon is assumed to act as channels for diffusion of adsorbate molecules onto small pores, therefore, promotes the adsorption rate of both phenol and MB. In phenol solution, water molecules firstly adsorb on surface oxygen groups by H-bonding and subsequently form water clusters, which cause partial blockage of the micropores, deduce electrons from the π-electron system of the carbon basal planes, hence, impede or prevent phenol adsorption. On the contrary, in MB solution, the oxygen groups prefer to combine with MB + cations than water molecules, which lead to the increase of MB adsorption capacity.

  11. Competitive adsorption of ibuprofen and amoxicillin mixtures from aqueous solution on activated carbons.

    PubMed

    Mansouri, Hayet; Carmona, Rocio J; Gomis-Berenguer, Alicia; Souissi-Najar, Souad; Ouederni, Abdelmottaleb; Ania, Conchi O

    2015-07-01

    This work investigates the competitive adsorption under dynamic and equilibrium conditions of ibuprofen (IBU) and amoxicillin (AMX), two widely consumed pharmaceuticals, on nanoporous carbons of different characteristics. Batch adsorption experiments of pure components in water and their binary mixtures were carried out to measure both adsorption equilibrium and kinetics, and dynamic tests were performed to validate the simultaneous removal of the mixtures in breakthrough experiments. The equilibrium adsorption capacities evaluated from pure component solutions were higher than those measured in dynamic conditions, and were found to depend on the porous features of the adsorbent and the nature of the specific/dispersive interactions that are controlled by the solution pH, density of surface change on the carbon and ionization of the pollutant. A marked roll-up effect was observed for AMX retention on the hydrophobic carbons, not seen for the functionalized adsorbent likely due to the lower affinity of amoxicillin towards the carbon adsorbent. Dynamic adsorption of binary mixtures from wastewater of high salinity and alkalinity showed a slight increase in IBU uptake and a reduced adsorption of AMX, demonstrating the feasibility of the simultaneous removal of both compounds from complex water matrices.

  12. Optimization of mesoporous carbons for efficient adsorption of berberine hydrochloride from aqueous solutions.

    PubMed

    Li, Yin; Fu, Jie; Deng, Shuguang; Lu, Xiuyang

    2014-06-15

    Sixteen mesoporous carbon adsorbents were synthesized by varying the ratio of soft to hard templates in order to optimize the pore textural properties of these adsorbents. The mesoporous carbon adsorbents have a high BET specific surface area (1590.3-2193.5 m(2)/g), large pore volume (1.72-2.56 cm(3)/g), and uniform pore size distribution with a median pore diameter ranging from 3.51 nm to 4.52 nm. It was observed that pore textural properties of the carbon adsorbents critically depend on the molar ratio of carbon sources to templates, and the hard template plays a more important role than the soft template in manipulating the pore textures. Adsorption isotherms of berberine hydrochloride at 303 K were measured to evaluate the adsorption efficacy of these adsorbents. The adsorption of berberine hydrochloride from aqueous solutions on the sixteen mesoporous carbon adsorbents synthesized in this work is very efficient, and the adsorption equilibrium capacities on all samples are more than double the adsorption capacities of berberine hydrochloride of the benchmark adsorbents (polymer resins and spherical activated carbons) at similar conditions. It was observed from the adsorption experiments that the equilibrium adsorption amounts of berberine hydrochloride are strongly correlated with the BET specific surface area and pore volume of the adsorbents. The adsorbent with the highest BET of 2193.5 m(2)/g displayed the largest adsorption capacity of 574 mg/g at an equilibrium concentration of 0.10mg/mL of berberine hydrochloride in an aqueous solution. PMID:24767505

  13. Solar-Driven Reduction of Aqueous Protons Coupled to Selective Alcohol Oxidation with a Carbon Nitride–Molecular Ni Catalyst System

    PubMed Central

    2016-01-01

    Solar water-splitting represents an important strategy toward production of the storable and renewable fuel hydrogen. The water oxidation half-reaction typically proceeds with poor efficiency and produces the unprofitable and often damaging product, O2. Herein, we demonstrate an alternative approach and couple solar H2 generation with value-added organic substrate oxidation. Solar irradiation of a cyanamide surface-functionalized melon-type carbon nitride (NCNCNx) and a molecular nickel(II) bis(diphosphine) H2-evolution catalyst (NiP) enabled the production of H2 with concomitant selective oxidation of benzylic alcohols to aldehydes in high yield under purely aqueous conditions, at room temperature and ambient pressure. This one-pot system maintained its activity over 24 h, generating products in 1:1 stoichiometry, separated in the gas and solution phases. The NCNCNx–NiP system showed an activity of 763 μmol (g CNx)−1 h–1 toward H2 and aldehyde production, a Ni-based turnover frequency of 76 h–1, and an external quantum efficiency of 15% (λ = 360 ± 10 nm). This precious metal-free and nontoxic photocatalytic system displays better performance than an analogous system containing platinum instead of NiP. Transient absorption spectroscopy revealed that the photoactivity of NCNCNx is due to efficient substrate oxidation of the material, which outweighs possible charge recombination compared to the nonfunctionalized melon-type carbon nitride. Photoexcited NCNCNx in the presence of an organic substrate can accumulate ultralong-lived “trapped electrons”, which allow for fuel generation in the dark. The artificial photosynthetic system thereby catalyzes a closed redox cycle showing 100% atom economy and generates two value-added products, a solar chemical, and solar fuel. PMID:27337491

  14. Solar-Driven Reduction of Aqueous Protons Coupled to Selective Alcohol Oxidation with a Carbon Nitride-Molecular Ni Catalyst System.

    PubMed

    Kasap, Hatice; Caputo, Christine A; Martindale, Benjamin C M; Godin, Robert; Lau, Vincent Wing-Hei; Lotsch, Bettina V; Durrant, James R; Reisner, Erwin

    2016-07-27

    Solar water-splitting represents an important strategy toward production of the storable and renewable fuel hydrogen. The water oxidation half-reaction typically proceeds with poor efficiency and produces the unprofitable and often damaging product, O2. Herein, we demonstrate an alternative approach and couple solar H2 generation with value-added organic substrate oxidation. Solar irradiation of a cyanamide surface-functionalized melon-type carbon nitride ((NCN)CNx) and a molecular nickel(II) bis(diphosphine) H2-evolution catalyst (NiP) enabled the production of H2 with concomitant selective oxidation of benzylic alcohols to aldehydes in high yield under purely aqueous conditions, at room temperature and ambient pressure. This one-pot system maintained its activity over 24 h, generating products in 1:1 stoichiometry, separated in the gas and solution phases. The (NCN)CNx-NiP system showed an activity of 763 μmol (g CNx)(-1) h(-1) toward H2 and aldehyde production, a Ni-based turnover frequency of 76 h(-1), and an external quantum efficiency of 15% (λ = 360 ± 10 nm). This precious metal-free and nontoxic photocatalytic system displays better performance than an analogous system containing platinum instead of NiP. Transient absorption spectroscopy revealed that the photoactivity of (NCN)CNx is due to efficient substrate oxidation of the material, which outweighs possible charge recombination compared to the nonfunctionalized melon-type carbon nitride. Photoexcited (NCN)CNx in the presence of an organic substrate can accumulate ultralong-lived "trapped electrons", which allow for fuel generation in the dark. The artificial photosynthetic system thereby catalyzes a closed redox cycle showing 100% atom economy and generates two value-added products, a solar chemical, and solar fuel.

  15. Solar-Driven Reduction of Aqueous Protons Coupled to Selective Alcohol Oxidation with a Carbon Nitride-Molecular Ni Catalyst System.

    PubMed

    Kasap, Hatice; Caputo, Christine A; Martindale, Benjamin C M; Godin, Robert; Lau, Vincent Wing-Hei; Lotsch, Bettina V; Durrant, James R; Reisner, Erwin

    2016-07-27

    Solar water-splitting represents an important strategy toward production of the storable and renewable fuel hydrogen. The water oxidation half-reaction typically proceeds with poor efficiency and produces the unprofitable and often damaging product, O2. Herein, we demonstrate an alternative approach and couple solar H2 generation with value-added organic substrate oxidation. Solar irradiation of a cyanamide surface-functionalized melon-type carbon nitride ((NCN)CNx) and a molecular nickel(II) bis(diphosphine) H2-evolution catalyst (NiP) enabled the production of H2 with concomitant selective oxidation of benzylic alcohols to aldehydes in high yield under purely aqueous conditions, at room temperature and ambient pressure. This one-pot system maintained its activity over 24 h, generating products in 1:1 stoichiometry, separated in the gas and solution phases. The (NCN)CNx-NiP system showed an activity of 763 μmol (g CNx)(-1) h(-1) toward H2 and aldehyde production, a Ni-based turnover frequency of 76 h(-1), and an external quantum efficiency of 15% (λ = 360 ± 10 nm). This precious metal-free and nontoxic photocatalytic system displays better performance than an analogous system containing platinum instead of NiP. Transient absorption spectroscopy revealed that the photoactivity of (NCN)CNx is due to efficient substrate oxidation of the material, which outweighs possible charge recombination compared to the nonfunctionalized melon-type carbon nitride. Photoexcited (NCN)CNx in the presence of an organic substrate can accumulate ultralong-lived "trapped electrons", which allow for fuel generation in the dark. The artificial photosynthetic system thereby catalyzes a closed redox cycle showing 100% atom economy and generates two value-added products, a solar chemical, and solar fuel. PMID:27337491

  16. Adsorption behavior and mechanisms of ciprofloxacin from aqueous solution by ordered mesoporous carbon and bamboo-based carbon.

    PubMed

    Peng, Xiaoming; Hu, Fengping; Lam, Frank L-Y; Wang, Yajun; Liu, Zhanmeng; Dai, Hongling

    2015-12-15

    The performances of ordered mesoporous carbon CMK-3 (OMC), bamboo-based carbon (BC), and these two kinds of adsorbents modified by thermal treatment in the ammonia atmosphere at high temperatures were evaluated for the removal fluoroquinolone antibiotic (ciprofloxacin) from aqueous solution. The adsorption behavior of ciprofloxacin (CIP) onto OMC and BC including adsorption isotherms and kinetics were investigated. The effect of various factors (pH, ionic strength and temperature) on the adsorption process was also investigated. The results demonstrated that the modified OMC and BC can further enhance the adsorption capacity due to introduce of alkaline nitrogen functionalities on the carbon surface. And their maximum adsorption capacity reached as high as 233.37mgg(-1) and 362.94mgg(-1) under the same experimental conditions, respectively. This is primarily ascribed to the positive effect of the surface basicity. The highest sorption was observed at the lowest solubility, which indicated that hydrophobic interaction was the dominant sorption mechanism for CIP uptake onto the four adsorbents. The adsorption data of antibiotics was analyzed by Langmuir and Freundlich model, and the better correlation was achieved by the Langmuir isotherm. The kinetic data showed that the adsorption of CIP onto OMC and BC follow closely the pseudo-second order model. The removal efficiency and adsorption capacity increased with increasing temperature. The results of thermodynamic study indicated that the adsorption process was a spontaneous and endothermic. PMID:26385593

  17. A novel one-pot and one-step microwave-assisted cyclization-methylation reaction of amino alcohols and acetylated derivatives with dimethyl carbonate and TBAC.

    PubMed

    Ochoa-Terán, Adrián; Guerrero, Leticia; Rivero, Ignacio A

    2014-01-01

    A simple and efficient microwave-assisted methodology for the synthesis of 4-substituted-3-methyl-1,3-oxazolidin-2-ones from amino alcohols catalyzed by a ionic liquid was developed. This novel one-pot and one-step cyclization-methylation reaction represents an easier and faster method than any other reported protocols that can be used to obtain the desired products in good yields and high purity. Applying microwave irradiation at 130°C in the presence of TBAC, dimethyl carbonate acts simultaneously as carbonylating and methylating agent and surprisingly promotes an in situ basic trans esterification when a N-acetylated amino alcohol is used as starting material. Furthermore, dimethyl carbonate worked better than diethyl carbonate in performing this reaction. PMID:25692177

  18. A Novel One-Pot and One-Step Microwave-Assisted Cyclization-Methylation Reaction of Amino Alcohols and Acetylated Derivatives with Dimethyl Carbonate and TBAC

    PubMed Central

    Ochoa-Terán, Adrián; Guerrero, Leticia; Rivero, Ignacio A.

    2014-01-01

    A simple and efficient microwave-assisted methodology for the synthesis of 4-substituted-3-methyl-1,3-oxazolidin-2-ones from amino alcohols catalyzed by a ionic liquid was developed. This novel one-pot and one-step cyclization-methylation reaction represents an easier and faster method than any other reported protocols that can be used to obtain the desired products in good yields and high purity. Applying microwave irradiation at 130°C in the presence of TBAC, dimethyl carbonate acts simultaneously as carbonylating and methylating agent and surprisingly promotes an in situ basic trans esterification when a N-acetylated amino alcohol is used as starting material. Furthermore, dimethyl carbonate worked better than diethyl carbonate in performing this reaction. PMID:25692177

  19. Transport of ions in mesoporous carbon electrodes during capacitive deionization of high-salinity solutions.

    PubMed

    Sharma, K; Kim, Y-H; Gabitto, J; Mayes, R T; Yiacoumi, S; Bilheux, H Z; Walker, L M H; Dai, S; Tsouris, C

    2015-01-27

    Desalination of high-salinity solutions has been studied using a novel experimental technique and a theoretical model. Neutron imaging has been employed to visualize lithium ions in mesoporous carbon materials, which are used as electrodes in capacitive deionization (CDI) for water desalination. Experiments were conducted with a flow-through CDI cell designed for neutron imaging and with lithium-6 chloride ((6)LiCl) as the electrolyte. Sequences of neutron images have been obtained at a relatively high concentration of (6)LiCl solution to provide information on the transport of ions within the electrodes. A new model that computes the individual ionic concentration profiles inside mesoporous carbon electrodes has been used to simulate the CDI process. Modifications have also been introduced into the simulation model to calculate results at high electrolyte concentrations. Experimental data and simulation results provide insight into why CDI is not effective for desalination of high ionic-strength solutions. The combination of experimental information, obtained through neutron imaging, with the theoretical model will help in the design of CDI devices, which can improve the process for high ionic-strength solutions.

  20. Removal of copper and cadmium from aqueous solution using switchgrass biochar produced via hydrothermal carbonization process.

    PubMed

    Regmi, Pusker; Garcia Moscoso, Jose Luis; Kumar, Sandeep; Cao, Xiaoyan; Mao, Jingdong; Schafran, Gary

    2012-10-30

    Biochar produced from switchgrass via hydrothermal carbonization (HTC) was used as a sorbent for the removal of copper and cadmium from aqueous solution. The cold activation process using KOH at room temperature was developed to enhance the porous structure and sorption properties of the HTC biochar. The sorption efficiency of HTC biochar and alkali activated HTC biochar (HTCB) for removing copper and cadmium from aqueous solution were compared with commercially available powdered activated carbon (PAC). The present batch adsorption study describes the effects of solution pH, biochar dose, and contact time on copper and cadmium removal efficiency from single metal ion aqueous solutions. The activated HTCB exhibited a higher adsorption potential for copper and cadmium than HTC biochar and PAC. Experiments conducted with an initial metal concentration of 40 mg/L at pH 5.0 and contact time of 24 h resulted in close to 100% copper and cadmium removal by activated HTCB at 2 g/L, far greater than what was observed for HTC biochar (16% and 5.6%) and PAC (4% and 7.7%). The adsorption capacities of activated HTCB for cadmium removal were 34 mg/g (0.313 mmol/g) and copper removal was 31 mg/g (0.503 mmol/g). PMID:22687632

  1. Unusually high dispersion of nitrogen-doped carbon nanotubes in DNA solution.

    PubMed

    Kim, Jin Hee; Kataoka, Masakazu; Fujisawa, Kazunori; Tojo, Tomohiro; Muramatsu, Hiroyuki; Vega-Díaz, Sofía M; Tristán-López, F; Hayashi, Takuya; Kim, Yoong Ahm; Endo, Morinobu; Terrones, Mauricio; Dresselhaus, Mildred S

    2011-12-01

    The dispersibility in a DNA solution of bundled multiwalled carbon nanotubes (MWCNTs), having different chemical functional groups on the CNT sidewall, was investigated by optical spectroscopy. We observed that the dispersibility of nitrogen (N)-doped MWCNTs was significantly higher than that of pure MWCNTs and MWCNTs synthesized in the presence of ethanol. This result is supported by the larger amount of adsorbed DNA on N-doped MWCNTs, as well as by the higher binding energy established between nucleobases and the N-doped CNTs. Pure MWCNTs are dispersed in DNA solution via van der Waals and hydrophobic interactions; in contrast, the nitrogenated sites within N-doped MWCNTs provided additional sites for interactions that are important to disperse nanotubes in DNA solutions.

  2. Electrolyte interactions with vapor dosed and solution dosed carbon monoxide on platinum (111)

    NASA Astrophysics Data System (ADS)

    Borup, R. L.; Sauer, D. E.; Stuve, E. M.

    1997-03-01

    Carbon monoxide adsorption and interactions with electrolyte species were examined for a Pt(111) electrode in 0.1M HClO 4. The experiments were conducted with an ex situ ultrahigh vacuum (UHV)-electrochemical system, with CO being adsorbed either from the vapor phase in the vacuum chamber or from solution. CO oxidation coulometry and cyclic voltammetry were used to characterize CO coverage in solution, and thermal desorption spectroscopy was used to measure CO coverage in vacuum, desorption kinetics and to detect coadsorbed electrolyte species. In agreement with earlier studies, the saturation coverage of 0.68 ML of CO from solution dosing is nearly 40% greater than the saturation coverage of 0.50 ML in vacuum at room temperature. The higher saturation coverages survive transfer to vacuum, but only in the presence of coadsorbed electrolyte species (H 2O and ClO 4) retained after removal of the electrode from the electrolyte. In the absence of coadsorbed electrolyte species, saturated, solution dosed CO transferred to vacuum exhibits the same coverage as vapor dosed CO. Interaction between CO and electrolyte species was confirmed through detection of both in thermal desorption following immersion of a vapor dosed CO adlayer into solution and back-transfer to vacuum. Kinetic modeling of CO thermal desorption showed that, regardless of whether CO is adsorbed from solution or from vapor, the COCO repulsive interactions are approximately 40% less when electrolyte species are retained than when they are absent.

  3. N-, O-, and S-tridoped nanoporous carbons as selective catalysts for oxygen reduction and alcohol oxidation reactions.

    PubMed

    Meng, Yuying; Voiry, Damien; Goswami, Anandarup; Zou, Xiaoxin; Huang, Xiaoxi; Chhowalla, Manish; Liu, Zhongwu; Asefa, Tewodros

    2014-10-01

    Replacing rare and expensive metal catalysts with inexpensive and earth-abundant ones is currently among the major goals of sustainable chemistry. Herein we report the synthesis of N-, O-, and S-tridoped, polypyrrole-derived nanoporous carbons (NOSCs) that can serve as metal-free, selective electrocatalysts and catalysts for oxygen reduction reaction (ORR) and alcohol oxidation reaction (AOR), respectively. The NOSCs are synthesized via polymerization of pyrrole using (NH4)2S2O8 as oxidant and colloidal silica nanoparticles as templates, followed by carbonization of the resulting S-containing polypyrrole/silica composite materials and then removal of the silica templates. The NOSCs exhibit good catalytic activity toward ORR with low onset potential and low Tafel slope, along with different electron-transfer numbers, or in other words, different ratios H2O/H2O2 as products, depending on the relative amount of colloidal silica used as templates. The NOSCs also effectively catalyze AOR at relatively low temperature, giving good conversions and high selectivity.

  4. Flow injection analysis-isotope ratio mass spectrometry for bulk carbon stable isotope analysis of alcoholic beverages.

    PubMed

    Jochmann, Maik A; Steinmann, Dirk; Stephan, Manuel; Schmidt, Torsten C

    2009-11-25

    A new method for bulk carbon isotope ratio determination of water-soluble samples is presented that is based on flow injection analysis-isotope ratio mass spectrometry (FIA-IRMS) using an LC IsoLink interface. Advantages of the method are that (i) only very small amounts of sample are required (2-5 microL of the sample for up to 200 possible injections), (ii) it avoids complex sample preparation procedures such as needed for EA-IRMS analysis (only sample dilution and injection,) and (iii) high throughput due to short analysis times is possible (approximately 15 min for five replicates). The method was first tested and evaluated as a fast screening method with industrially produced ethanol samples, and additionally the applicability was tested by the measurement of 81 alcoholic beverages, for example, whiskey, brandy, vodka, tequila, and others. The minimal sample concentration required for precise and reproducible measurements was around 50 microL L(-1) ethanol/water (1.71 mM carbon). The limit of repeatability was determined to be r=0.49%. FIA-IRMS represents a fast screening method for beverage authenticity control. Due to this, samples can be prescreened as a decisive criterion for more detailed investigations by HPLC-IRMS or multielement GC-IRMS measurements for a verification of adulteration. PMID:19856915

  5. Fabrication of carbon nanotube high-frequency nanoelectronic biosensor for sensing in high ionic strength solutions.

    PubMed

    Kulkarni, Girish S; Zhong, Zhaohui

    2013-01-01

    The unique electronic properties and high surface-to-volume ratios of single-walled carbon nanotubes (SWNT) and semiconductor nanowires (NW) make them good candidates for high sensitivity biosensors. When a charged molecule binds to such a sensor surface, it alters the carrier density in the sensor, resulting in changes in its DC conductance. However, in an ionic solution a charged surface also attracts counter-ions from the solution, forming an electrical double layer (EDL). This EDL effectively screens off the charge, and in physiologically relevant conditions ~100 millimolar (mM), the characteristic charge screening length (Debye length) is less than a nanometer (nm). Thus, in high ionic strength solutions, charge based (DC) detection is fundamentally impeded. We overcome charge screening effects by detecting molecular dipoles rather than charges at high frequency, by operating carbon nanotube field effect transistors as high frequency mixers. At high frequencies, the AC drive force can no longer overcome the solution drag and the ions in solution do not have sufficient time to form the EDL. Further, frequency mixing technique allows us to operate at frequencies high enough to overcome ionic screening, and yet detect the sensing signals at lower frequencies. Also, the high transconductance of SWNT transistors provides an internal gain for the sensing signal, which obviates the need for external signal amplifier. Here, we describe the protocol to (a) fabricate SWNT transistors, (b) functionalize biomolecules to the nanotube, (c) design and stamp a poly-dimethylsiloxane (PDMS) micro-fluidic chamber onto the device, and (d) carry out high frequency sensing in different ionic strength solutions. PMID:23912795

  6. Fabrication of carbon nanotube high-frequency nanoelectronic biosensor for sensing in high ionic strength solutions.

    PubMed

    Kulkarni, Girish S; Zhong, Zhaohui

    2013-01-01

    The unique electronic properties and high surface-to-volume ratios of single-walled carbon nanotubes (SWNT) and semiconductor nanowires (NW) make them good candidates for high sensitivity biosensors. When a charged molecule binds to such a sensor surface, it alters the carrier density in the sensor, resulting in changes in its DC conductance. However, in an ionic solution a charged surface also attracts counter-ions from the solution, forming an electrical double layer (EDL). This EDL effectively screens off the charge, and in physiologically relevant conditions ~100 millimolar (mM), the characteristic charge screening length (Debye length) is less than a nanometer (nm). Thus, in high ionic strength solutions, charge based (DC) detection is fundamentally impeded. We overcome charge screening effects by detecting molecular dipoles rather than charges at high frequency, by operating carbon nanotube field effect transistors as high frequency mixers. At high frequencies, the AC drive force can no longer overcome the solution drag and the ions in solution do not have sufficient time to form the EDL. Further, frequency mixing technique allows us to operate at frequencies high enough to overcome ionic screening, and yet detect the sensing signals at lower frequencies. Also, the high transconductance of SWNT transistors provides an internal gain for the sensing signal, which obviates the need for external signal amplifier. Here, we describe the protocol to (a) fabricate SWNT transistors, (b) functionalize biomolecules to the nanotube, (c) design and stamp a poly-dimethylsiloxane (PDMS) micro-fluidic chamber onto the device, and (d) carry out high frequency sensing in different ionic strength solutions.

  7. Fabrication of Carbon Nanotube High-Frequency Nanoelectronic Biosensor for Sensing in High Ionic Strength Solutions

    PubMed Central

    Kulkarni, Girish S.; Zhong, Zhaohui

    2013-01-01

    The unique electronic properties and high surface-to-volume ratios of single-walled carbon nanotubes (SWNT) and semiconductor nanowires (NW) 1-4 make them good candidates for high sensitivity biosensors. When a charged molecule binds to such a sensor surface, it alters the carrier density5 in the sensor, resulting in changes in its DC conductance. However, in an ionic solution a charged surface also attracts counter-ions from the solution, forming an electrical double layer (EDL). This EDL effectively screens off the charge, and in physiologically relevant conditions ~100 millimolar (mM), the characteristic charge screening length (Debye length) is less than a nanometer (nm). Thus, in high ionic strength solutions, charge based (DC) detection is fundamentally impeded6-8. We overcome charge screening effects by detecting molecular dipoles rather than charges at high frequency, by operating carbon nanotube field effect transistors as high frequency mixers9-11. At high frequencies, the AC drive force can no longer overcome the solution drag and the ions in solution do not have sufficient time to form the EDL. Further, frequency mixing technique allows us to operate at frequencies high enough to overcome ionic screening, and yet detect the sensing signals at lower frequencies11-12. Also, the high transconductance of SWNT transistors provides an internal gain for the sensing signal, which obviates the need for external signal amplifier. Here, we describe the protocol to (a) fabricate SWNT transistors, (b) functionalize biomolecules to the nanotube13, (c) design and stamp a poly-dimethylsiloxane (PDMS) micro-fluidic chamber14 onto the device, and (d) carry out high frequency sensing in different ionic strength solutions11. PMID:23912795

  8. Platinum-palladium bimetallic nanoparticles on graphitic carbon nitride modified carbon black: A highly electroactive and durable catalyst for electrooxidation of alcohols

    NASA Astrophysics Data System (ADS)

    Qian, Huayu; Chen, Shouwen; Fu, Yongsheng; Wang, Xin

    2015-12-01

    A composite catalyst consisting of Pt-Pd bimetallic nanoparticles (NPs) and graphitic carbon nitride (g-C3N4) modified carbon black (CB) is designed and fabricated by a facile two-step approach. The resulting catalyst exhibits unprecedented high catalytic activity and excellent long-term stability for electrooxidation of alcohols (methanol, ethanol, ethylene glycol and glycerol) in alkaline media. The superior electrochemical performance of the composite catalyst is attributed to the specific characteristics of the unique nanostructure and the synergistic effects of individual components, including the complementary roles of Pt (dehydrogenation site) and Pd (removal of CO-like species), the template effect of the planar amino group of g-C3N4 for the dispersed decoration of Pt-Pd NPs, the high specific surface area of CB for the rapid diffusion of electrolyte and removal of the carbonaceous intermediates, as well as the structural stability of the support based on covalent interaction between g-C3N4 and CB for maintaining the durability of the catalytic system.

  9. Precipitation of Co(2+) carbonates from aqueous solution: insights on the amorphous to crystalline transformation.

    NASA Astrophysics Data System (ADS)

    González-López, Jorge; Fernández-González, Ángeles; Jiménez, Amalia

    2016-04-01

    Cobalt is toxic metal that is present only as a trace in the Earth crust. However, Co might concentrate on specific areas due to both natural and anthropogenic factors and thus, soils and groundwater can be contaminated. It is from this perspective that we are interested in the precipitation of cobalt carbonates, since co-precipitation with minerals phases is a well-known method for metal immobilization in the environment. In particular, the carbonates are widely used due to its reactivity and natural abundance. In order to evaluate the cobalt carbonate precipitation at room temperature, a simple experimental work was carried out in this work. The precipitation occurred via reaction of two common salts: 0.05M of CoCl2 and 0.05M of Na2CO3 in aqueous solution. After reaction, the precipitated solid was kept in the remaining water at 25 oC and under constant stirring for different aging times of 5 min, 1 and 5 hours, 1, 2, 4, 7, 30 and 60 days. In addition to the aging and precipitation experiments, we carried out experiments to determine the solubility of the solids. In these experiments each precipitate was dissolved in Milli-Q water until equilibrium was reached and then the aqueous solution was analyzed regarding Co2+ and total alkalinity. Furthermore, acid solution calorimetry of the products were attained. Finally, we modeled the results using the PHREEQC code. Solid and aqueous phase identification and characterization have been extensively reported in a previous work (González-López et al., 2015). The main results of our investigation were the initial precipitation of an amorphous cobalt carbonate that evolve towards a poorly crystalline cobalt hydroxide carbonate with aging treatment. Solubility of both phases have been calculated under two different approaches: precipitation and dissolution. Values of solubility from each approach were obtained with a general error due to differences in experiment conditions, for instance, ionic strength, temperature and

  10. [Investigation of FTIR spectra analysis on carbon dioxide absorption with improved amine solution].

    PubMed

    Yin, Wen-xuan; Liu, Jian-zhou; Gao, Li-ping; Jiang, Jing-liang; Wang, Zhi-hua

    2011-05-01

    Carbon dioxide is a major sort of greenhouse gas as well as important carbon resource. With the developments of industries, emission of carbon dioxide has increased sharply. Hence, controls of carbon dioxide emission and resource transformation have become the hotspot of current study. As a new kind of carbon resource, the fields of CO2 research and application are very extensive. Among those methods, the amine absorption has good qualities of faster absorption rate, higher efficiency and so on, so it has been widely studied. But organic amine have such shortcomings: high consumption of heat energy, strong corrosive and easy oxidated, now pursuer mainly focused on the organic amine modified. The results showed that, when the time the amount of antioxidant 1010 is 0.152, the absorption capacity is 2503.53 mL. the volume of analysis is 982.00 mL, and the absorption rate changes more slowly, by FTIR, Samples of its renewable-OH associating is not apparent that the antioxidant content in 1010, oxidation products of the MEA is acid or less oxidation and antioxidant 1010 product in early to respond fully to form stable non-radical compounds. Therefore, the best dosage of antioxidant 1010 is 0.15%. When the time that the amount of Na2SO3 is 0.15%, the absorption capacity is 2922.88 mL. Analysis of the volume is 723.00 mL, by FTIR, which reveals the oxidation products of the MEA is amide -C=O which in alkaline solution can be transiting into primary amine, and be easy absorbing CO2. Comparing the antioxygenic proerty of antioxidant 1010 with Na2SO3, from the absorption rate, the amount of absorption , Na2SO3's antioxidant properties is superior than antioxidant 1010; by infrared spectral analysis, 1010/20% MEA solution's oxidation products is the acid, Na2SO3/20% MEA solutions, the oxidation product is amide, amide solution is advantaged for absorbing CO2, So Na2SO3's antioxidant properties is superior than antioxidant 1010.

  11. Use of artificial sweeteners to promote alcohol consumption by rats.

    PubMed

    Plummer, J L; Hall, P M; Cmielewski, P L; Ilsley, A H; Ahern, M J

    1997-02-01

    Cirrhosis may be reliably produced in rats by exposing them intermittently to low levels of carbon tetrachloride vapour while feeding alcohol in the Lieber-DeCarli liquid diet. Providing the alcohol in drinking water that has been sweetened with sucrose is a cheaper and more convenient method but it does not yield reliable results. This study aimed to determine whether alcohol in drinking water sweetened with artificial sweeteners would give adequate alcohol intake to achieve the desired hepatic effects. Rats were fed alcohol (8% v/v) in drinking water sweetened with sucrose (5% w/v) (n = 12), or with one of the artificial sweeteners aspartame (0.025%), saccharin (0.025%) or cyclamate (0.05%) (n = 8 per agent). During the alcohol treatment the animals were exposed to carbon tetrachloride vapour, 40 ppm, six hours per night for five nights per week, over a period of 14 weeks. All groups achieved good alcohol intakes of 5-6 g/kg/day. Only one rat, in the aspartame group, became cirrhotic; all the others had varying degrees of fibrosis which did not differ significantly among the treatments. Although it was not effective in reliably achieving cirrhosis, sweetening the alcohol solution with artificial sweeteners led to reasonable alcohol intakes with resultant hepatic fibrosis, and without the high carbohydrate intake which occurs when sucrose is used.

  12. Lead and copper removal from aqueous solutions using carbon foam derived from phenol resin.

    PubMed

    Lee, Chang-Gu; Jeon, Jun-Woo; Hwang, Min-Jin; Ahn, Kyu-Hong; Park, Chanhyuk; Choi, Jae-Woo; Lee, Sang-Hyup

    2015-07-01

    Phenolic resin-based carbon foam was prepared as an adsorbent for removing heavy metals from aqueous solutions. The surface of the produced carbon foam had a well-developed open cell structure and the specific surface area according to the BET model was 458.59m(2)g(-1). Batch experiments showed that removal ratio increased in the order of copper (19.83%), zinc (34.35%), cadmium (59.82%), and lead (73.99%) in mixed solutions with the same initial concentration (50mgL(-1)). The results indicated that the Sips isotherm model was the most suitable for describing the experimental data of lead and copper. The maximum adsorption capacity of lead and copper determined to Sips model were 491mgg(-1) and 247mgg(-1). The obtained pore diffusion coefficients for lead and copper were found to be 1.02×10(-6) and 2.42×10(-7)m(2)s(-1), respectively. Post-sorption characteristics indicated that surface precipitation was the primary mechanism of lead and copper removal by the carbon foam, while the functional groups on the surface of the foam did not affect metal adsorption. PMID:25819762

  13. Effects of solution chemistry on the adsorption of ibuprofen and triclosan onto carbon nanotubes.

    PubMed

    Cho, Hyun-Hee; Huang, Haiou; Schwab, Kellogg

    2011-11-01

    Single-walled carbon nanotubes (SWCNTs), multiwalled carbon nanotubes (MWCNTs), and oxidized MWCNTs (O-MWCNTs) were studied for the adsorption of ibuprofen (IBU) and triclosan (TCS) as representative types of pharmaceutical and personal care products (PPCPs) under different chemical solution conditions. A good fitting of sorption isotherms was obtained using a Polanyi-Manes model (PMM). IBU and TCS sorption was stronger for SWCNTs than for MWCNTs due to higher specific surface area. The high oxygen content of O-MWCNT further depressed PPCP sorption. The sorption capacity of PPCPs was found to be pH-dependent, and more adsorption was observed at pHs below their pK(a) values. Ionic strength was also found to substantially affect TCS adsorption, with higher adsorption capacity observed for TCS at lower ionic strength. In the presence of a reference aquatic fulvic acid (FA), sorption of IBU and TCS was reduced due to the competitive sorption of FA on carbon nanotubes (CNTs). Sorption isotherm results with SWCNTs, MWCNTs and O-MWCNTs confirmed that the surface chemistry of CNTs, the chemical properties of PPCPs, and aqueous solution chemistry (pH, ionic strength, fulvic acid) all play an important role in PPCP adsorption onto CNTs.

  14. Lead and copper removal from aqueous solutions using carbon foam derived from phenol resin.

    PubMed

    Lee, Chang-Gu; Jeon, Jun-Woo; Hwang, Min-Jin; Ahn, Kyu-Hong; Park, Chanhyuk; Choi, Jae-Woo; Lee, Sang-Hyup

    2015-07-01

    Phenolic resin-based carbon foam was prepared as an adsorbent for removing heavy metals from aqueous solutions. The surface of the produced carbon foam had a well-developed open cell structure and the specific surface area according to the BET model was 458.59m(2)g(-1). Batch experiments showed that removal ratio increased in the order of copper (19.83%), zinc (34.35%), cadmium (59.82%), and lead (73.99%) in mixed solutions with the same initial concentration (50mgL(-1)). The results indicated that the Sips isotherm model was the most suitable for describing the experimental data of lead and copper. The maximum adsorption capacity of lead and copper determined to Sips model were 491mgg(-1) and 247mgg(-1). The obtained pore diffusion coefficients for lead and copper were found to be 1.02×10(-6) and 2.42×10(-7)m(2)s(-1), respectively. Post-sorption characteristics indicated that surface precipitation was the primary mechanism of lead and copper removal by the carbon foam, while the functional groups on the surface of the foam did not affect metal adsorption.

  15. Numerical investigation on the structural characteristics of multiple RBCs in a stenotic microcapillary under plasma-alcohol solution

    NASA Astrophysics Data System (ADS)

    Ni, Aleksey; Cheema, Taqi Ahmad; Park, Cheol Woo

    2015-05-01

    Alcohol significantly affects blood rheology and influences the mechanical behavior of red blood cells (RBCs). Previous studies indicate that plasma-RBC and multiple RBC interaction are important indicators for atherosclerosis progression. Therefore, multiphysics interactions under highly viscous conditions of alcohol consumption and stenosis structure must be investigated. A 2D microcapillary model, wherein multiple RBCs float through a stenotic structure, was established to investigate the effect of alcohol on cell motion and deformability under various flow conditions. Results show that the deformed cells inside the stenosis increase flow resistance and increase plasma velocity gradient in the pre and post stenotic regions. Moreover, the effect of the initial RBC position is important describing the RBC deformation pattern. The structural properties of RBCs may be significantly affected when the stenosis path is filled by cells that increase flow resistance.

  16. Dissolution of Uranium(IV) Oxide in Solutions of Ammonium Carbonate and Hydrogen Peroxide

    SciTech Connect

    Smith, Steven C.; Peper, Shane M.; Douglas, Matthew; Ziegelgruber, Kate L.; Finn, Erin C.

    2009-09-12

    Understanding the dissolution characteristics of uranium oxides is of fundamental scientific interest. Bench scale experiments were conducted to determine the optimal dissolution parameters of uranium(IV) oxide (UO2) powder in solutions of ammonium carbonate [(NH4)2CO3] and hydrogen peroxide (H2O2). Experimental parameters included variable peroxide and carbonate concentrations, and temperature. Results indicate the dissolution rate of UO2 in 1 M (NH4)2CO3 increases linearly with peroxide concentration ranging from 0.05 – 2 M (1:1 to 40:1 mol ratio H2O2:U), with no apparent maximum rate reached under the limited conditions used in our study. Temperature ranging studies show the dissolution rate of UO2 in 1 M (NH4)2CO3 and 0.1 M H2O2 (2:1 mol ratio H2O2:U) increases linearly from 15 °C to 60 °C, again with no apparent maximum rate reached. Dissolution of UO2 in solutions with constant [H2O2] and [(NH4)2CO3] ranging from 0.5 to 2 M showed no difference in rate; however dissolution was significantly reduced in 0.05 M (NH4)2CO3 solution. The results of this study demonstrate the influence of [H2O2], [(NH4)2CO3], and temperature on the dissolution of UO2 in peroxide-containing (NH4)2CO3 solutions. Future studies are planned to elucidate the solution and solid state complexes in these systems.

  17. Effect of solution additives on the performance of PMAN carbon anodes in 1M LiPF{sub 6}/EC-DMC solutions

    SciTech Connect

    Guidotti, R.A.; Johnson, B.J.

    1996-12-31

    A study was undertaken to examine the use of a number of solution additives in 1M LiPF{sub 6}/ethylene carbonate (EC)-dimethyl carbonate (DMC) solutions to improve the performance of carbon anodes derived from polymethylacrylonitrile (PMAN)-divinylbenzene (DVB) copolymers. The study goals were to improve the cycle life and reduce the formation of the passivation layer during the first reduction, thereby minimizing the irreversible-capacity losses. Additives studied were 12-crown-4 (12-Cr-4) ether, decalin, and dilithium phthalocyanine (Li{sub 2}Pc). The carbon performance was characterized by galvanostatic cycling, cyclic voltammetry, and complex-impedance spectroscopy. Limited success was obtained with 12-Cr-4 ether at 0.25 M and decalin at 1 v/o. Poor results were noted with Li{sub 2}Pc at 0.025 M and 0.5 M.

  18. Role of PF6- in the radiolytical and electrochemical degradation of propylene carbonate solutions

    NASA Astrophysics Data System (ADS)

    Ortiz, Daniel; Jimenez Gordon, Isabel; Legand, Solène; Dauvois, Vincent; Baltaze, Jean-Pierre; Marignier, Jean-Louis; Martin, Jean-Frédéric; Belloni, Jacqueline; Mostafavi, Mehran; Le Caër, Sophie

    2016-09-01

    The behavior under irradiation of neat propylene carbonate (PC), a co-solvent usually used in Li-ion batteries (LIB), and also of Li salt solutions is investigated. The decomposition of neat PC is studied using radiolysis in the pulse and steady state regime and is assigned to the ultrafast formation, in the reducing channel, of the radical anion PCrad - by electron attachment, followed by the ring cleavage, leading to CO. In the oxidative channel, the PC(sbnd H)rad radical is formed, generating CO2. The CO2 and CO yields are both close to the ionization yield of PC. The CO2 and CO productions in LiClO4, LiBF4 and LiN(CF3)2(SO2)2 solutions are similar as in neat PC. In contrast, in LiPF6/PC a strong impact on PC degradation is measured with a doubling of the CO2 yield due to the high reactivity of the electron towards PF6- observed in the picosecond range. A small number of oxide phosphine molecules are detected among the various products of the irradiated solutions, suggesting that most of them, observed in carbonate mixtures used in LIBs, arise from linear rather than from cyclical molecules. The similarity between the degradation by radiolysis or electrolysis highlights the interest of radiolysis as an accelerated aging method.

  19. Kinetics and thermodynamic study of aniline adsorption by multi-walled carbon nanotubes from aqueous solution.

    PubMed

    Al-Johani, Hind; Abdel Salam, Mohamed

    2011-08-15

    Multi-walled carbon nanotubes (MWCNTs) were used in the adsorptive removal of aniline, an organic pollutant, from an aqueous solution. It was found that carbon nanotubes with a higher specific surface area adsorbed and removed more aniline from an aqueous solution. The adsorption was dependent on factors, such as MWCNTs dosage, contact time, aniline concentration, solution pH and temperature. The adsorption study was analyzed kinetically, and the results revealed that the adsorption followed pseudo-second order kinetics with good correlation coefficients. In addition, it was found that the adsorption of aniline occurred in two consecutive steps, including the slow intra-particle diffusion of aniline molecules through the nanotubes. Various thermodynamic parameters, including the Gibbs free energy change (ΔG°), enthalpy change (ΔH°) and entropy change (ΔS°), were calculated. The results indicated that the spontaneity of the adsorption, exothermic nature of the adsorption and the decrease in the randomness reported as ΔG°, ΔH° and ΔS°, respectively, were all negative.

  20. Integration of High-Purity Carbon Nanotube Solution into Electronic Devices

    NASA Astrophysics Data System (ADS)

    Tulevski, George; IBM TJ Watson Reserach Center Team

    Due to their exceptional electronic properties, carbon nanotubes (cnt) are leading candidates to be employed as channel materials in future nanoelectronic devices. A key bottleneck to realizing device integration is the sorting of carbon nanotubes, namely the isolation of high-purity, semiconducting cnt solutions. This talk will describe our efforts in using polymer-based sorting methods to isolate high-density and high-purity semiconducting cnt solutions. We explore the dependence of starting material and polymer to cnt ratio on the effectiveness of the separation. We confirm optically and electrically that the semiconducting purity is >99.99% through several thousand individual device measurements. In addition to single-cnt devices, thin-film transistors were also fabricated and tested. Due to the high purity of the solutions, device switching (~105 ION/IOFF) was observed at channel lengths below the percolation threshold (<500 nm). Operating below the percolation threshold allows for devices with much higher current densities and effective mobilities as transport is now the result of direct transport as opposed to hopping between cnts.

  1. The Electrochemical Behavior of Zn-Mn Alloy Coating in Carbonated Concrete Solution

    NASA Astrophysics Data System (ADS)

    Touazi, S.; Bučko, M.; Makhloufi, L.; Legat, A.; Bajat, J. B.

    2016-05-01

    In order to improve the protective performance of Zn coating on reinforcing steel in concrete, the electrochemical deposition of Zn-Mn coatings was conducted on steel surface. The morphology, chemical and phase compositions of Zn-Mn coatings obtained from sulfate-citrate bath were investigated in the first part of paper. In the second part, the obtained deposits were tested in solution simulating carbonated concrete, consisting of NaHCO3 and Na2CO3. Data obtained from Tafel analysis showed higher corrosion resistance for Zn-Mn alloy deposits obtained at -1700 and -1800mV versus SCE, when compared to pure Zn deposit. Impedance spectroscopy investigations revealed that the total impedance of Zn-Mn coatings increased steadily with time, and was significantly higher as compared to pure Zn after 24h in corrosion solution. On the contrary, for pure Zn, the impedance increased in the first 12h, and then decreased during prolonged exposure time, which can be explained by rapid growth of nonprotective white rust and the degradation of zinc coating, as was confirmed by optical microscope after 24h of immersion in carbonated concrete pore solution.

  2. ANIONIC EXCHANGE PROCESS FOR THE RECOVERY OF URANIUM AND VANADIUM FROM CARBONATE SOLUTIONS

    DOEpatents

    Bailes, R.H.; Ellis, D.A.; Long, R.S.

    1958-12-16

    Uranium and vanadium can be economically purified and recovered from non- salt roast carbonate leach liquors by adsorption on a strongly basic anionic exchange resin and subsequent selective elution by one of three alternative methods. Method 1 comprises selectively eluting uranium from the resin with an ammonium sulfate solution followed by eluting vanadium from the resin with either 5 M NaCl, saturated (NH/sub 4/)/sub 2/CO/sub 3/, saturated NaHCO/sub 3/, 1 M NaOH, or saturated S0/sub 2/ solutions. Method II comprises selectively eluting vanadium from the resin with either concentrated NaCl or S0/sub 2/ solutions subsequent to pretreatment of the column with either S0/sub 2/ gas, 1 N HCl, or 0.1 N H/sub 2/8O/sub 4/ followed by eluting uranium from the resin with solutions containing 0.9 M NH/sub 4/Cl or NaCl and 0.1 Cl. Method III comprises flowing the carbonate leac solutlon through a first column of a strongly basic anlonlc exchange resin untll vanadium breakthrough occurs, so that the effluent solution is enriched ln uranium content and the vanadium is chiefly retalned by the resln, absorbing the uranlum from the enriched effluent solution on a second column of a strongly basic anionic exchange resin, pretreating the first column with either 0.1 N HCl, 0.1 H/sub 2/SO/sub 4/, C0/sub 2/ gas, or ammonium sulfate, selectively eluting the vanadlum from the column with saturated S0/sub 2/ solution, pretreatlng the second column with either 0.1 N HCl or S0/sub 2/ gas, selectively eluting residual vanadium from the column with saturated S0/sub 2/ solution, and then eluting the uranium from the column with either 0.1 N HCl and 1 N NaCl orO.l N HCl and 1 N NH/sub 4/Cl.

  3. Multi-walled carbon nanotubes as the gas chromatographic stationary phase: role of their functionalization in the analysis of aliphatic alcohols and esters.

    PubMed

    Merli, Daniele; Speltini, Andrea; Ravelli, Davide; Quartarone, Eliana; Costa, Lorenzo; Profumo, Antonella

    2010-11-12

    Presented hereafter is the novel application of differently functionalized multi-walled carbon nanotubes (f-MWCNTs) as stationary phases for the GC separation of C(1)-C(5) alcohols and esters. Low-cost packed columns, easily prepared in laboratory, were used with satisfactory results. Depending on the functional groups introduced on the pristine MWCNTs, remarkably different behaviours have been observed, thus indicating that derivatization is a key factor to achieve optimal resolution. The best performance was shown by the 2,2'-(ethylenedioxy)diethylamine derivatized MWCNTs, allowing the separation of alcohol isomers, for this reason chosen for the investigation of fermentation by-products in distilled spirits. The degree of derivatization has been assessed for each packing material by thermogravimetric analysis (TGA). A computational study has been performed to correlate the physico-chemical properties of alcohol probes with the retention behaviour.

  4. Dynamic effects in the production of diamond from solid-solution carbon

    SciTech Connect

    Sobolev, V.V.; Didyk, R.P.; Merezhko, Y.I.; Skidanenko, A.I.; Slobodskoi, V.Y.

    1984-03-01

    The authors examine the scope for diamond to grow at atmospheric pressure in iron alloys. For the purpose of this investigation, diamond nuclei were produced in a cast-iron specimen by a dynamic pressure of 80-90GPa. The mass proportion of diamond polycrystals of maximum size 40-50 ..mu..m did not exceed 1%. The largest diamond content occurred in the fraction 0.1-5 ..mu..m and constituted about 80%. The studies show that: the presence of diamond inclusions in a metal matrix substantially influences the structural transformations during isothermal heating and slow cooling; the solid-solution carbon, the carbon compounds, and the graphite inclusions can serve as sources of carbon in the growth of diamond crystals in the metastable region; and dynamic pressures generate numerous defects in cast-iron specimens, which are sources of vacancies, which facilitate the diffusion of the carbon to the growing diamond crystals and the removal of iron from them.

  5. Mass-transfer in solution: on the context and cause of spherulitic lacustrine carbonate deposits

    NASA Astrophysics Data System (ADS)

    Rogerson, Michael; Mercedes-Martin, Ramon; Brasier, Alex; Vonhof, Hubert; Prior, Tim; Fellows, Simon; Reijmer, John; Pedley, Martyn; McGill, Rona

    2016-04-01

    Understanding how laterally extensive spherulitic carbonate deposits originated in the 'Pre-Salt' Aptian volcanic-influenced lacustrine basins of Brazil and Angola is challenging, especially as few good analog systems are known to compare the Pre-Salt to. Here, we report a particularly good analog system in the Carboniferous of the Scotland (the East Kirkton Limestone), and examine the geochemical and sedimentological context in which spherular radial calcite has developed. Using empirical and theoretical approaches, we analyse the link between metal mobilization from sub-surface volcaniclastic rocks, and the potential precipitation of carbonates, Mg-Si minerals and chalcedony in a lacustrine spherulitic carbonate setting. This suite of minerals at the surface can be explained by CO2 ingassing to a springwater derived from reaction of alkali igneous rocks in the subsurface with meteoric groundwater. This forms a 'source-to-sink' system occurring entirely in solution in the subsurface, but demonstrably capable of forming significant depositional units at the surface. We hypothesise that analogous processes occurring on a larger scale are implicated in the development of the 'Pre-Salt' spherulitic carbonate deposits.

  6. Direct determination of carbon dioxide in aqueous solution using mid-infrared quantum cascade lasers.

    PubMed

    Schaden, S; Haberkorn, M; Frank, J; Baena, J R; Lendl, B

    2004-06-01

    A method for the direct determination of carbon dioxide in aqueous solutions using a room-temperature mid-infrared (MIR) quantum cascade laser at 2330 cm(-1) is reported. The absorption values of different carbon dioxide concentrations were measured in a 119 microm CaF2 flow-through cell. An optical system made of parabolic mirrors was used to probe the flow cell and to focus the laser beam on the mercury cadmium telluride (MCT) detector. Aqueous carbon dioxide standards were prepared by feeding different mixtures of gaseous N2 and CO2 through wash bottles at controlled temperature. The concentration of the dissolved CO2 was calculated according to Henry's law, taking into account the temperature and the partial pressure of CO2. The carbon dioxide standards were connected via a selection valve to a peristaltic pump for subsequent, automated measurement in the flow-through cell. A calibration curve was obtained in the range of 0.338 to 1.350 g/L CO2 with a standard deviation of the method sxo equal to 19.4 mg/L CO2. The limit of detection was calculated as three times the baseline noise over time and was determined to be 39 mg/L.

  7. Carbon enters silica forming a cristobalite-type CO2-SiO2 solid solution.

    PubMed

    Santoro, Mario; Gorelli, Federico A; Bini, Roberto; Salamat, Ashkan; Garbarino, Gaston; Levelut, Claire; Cambon, Olivier; Haines, Julien

    2014-01-01

    Extreme conditions permit unique materials to be synthesized and can significantly update our view of the periodic table. In the case of group IV elements, carbon was always considered to be distinct with respect to its heavier homologues in forming oxides. Here we report the synthesis of a crystalline CO2-SiO2 solid solution by reacting carbon dioxide and silica in a laser-heated diamond anvil cell (P = 16-22 GPa, T>4,000 K), showing that carbon enters silica. Remarkably, this material is recovered to ambient conditions. X-ray diffraction shows that the crystal adopts a densely packed α-cristobalite structure (P4(1)2(1)2) with carbon and silicon in fourfold coordination to oxygen at pressures where silica normally adopts a sixfold coordinated rutile-type stishovite structure. An average formula of C0.6(1)Si0.4(1)O2 is consistent with X-ray diffraction and Raman spectroscopy results. These findings may modify our view on oxide chemistry, which is of great interest for materials science, as well as Earth and planetary sciences. PMID:24781844

  8. Role of the surface chemistry of activated carbons in dye removal from aqueous solution

    NASA Astrophysics Data System (ADS)

    Zhou, Hua-lei; Zhen, Wen-juan; Zhu, Qian; Wu, Xiao-bin; Chang, Zhi-dong; Li, Wen-jun

    2015-07-01

    Commercial activated carbons were modified by a series of chemical or physical treatments using H2O2, NH3, and heating under N2 flow without notably changing their pore structures. The resultant carbons were characterized by N2 adsorption and Bohem titration and then used to remove Ponceau 4R, methyl orange and brilliant blue from aqueous solutions. Surface chemistry was found to play a significantly different role in removing these three compounds. The removal of anionic Ponceau 4R increases with increasing carbon surface basicity due to the predominant dispersive interaction mechanism. In contrast, surface chemistry has little effect on the removal of anionic methyl orange, which can be explained by two parallel mechanisms involving electrostatic and dispersive interactions due to the basic amine group in a dye molecule. The influence of surface chemistry on the removal of amphoteric brilliant blue dye can also be ignored due to a weak interaction between the carbons and dye molecules, which is resulted from strong cohesive energy from electrostatic forces inside amphoteric dye molecules.

  9. Free-solution interaction assay of carbonic anhydrase to its inhibitors using back-scattering interferometry.

    PubMed

    Morcos, Ereny F; Kussrow, Amanda; Enders, Carolyn; Bornhop, Darryl

    2010-11-01

    Back-scattering interferometry (BSI) is a label-free, free-solution, small-volume technique used for characterizing binding interactions, which is also relevant to a growing number of biosensing applications including drug discovery. Here, we use BSI to characterize the interaction of carbonic anhydrase enzyme II with five well-known carbonic anhydrase enzyme II inhibitors (± sulpiride, sulfanilamide, benzene sulfonamide, dansylamide, and acetazolamide) in the presence of DMSO. Dissociation constants calculated for each interaction were consistent with literature values previously obtained using surface plasmon resonance and fluorescence-based competition assays. Results demonstrate the potential of BSI as a drug-screening tool which is fully compatible with DMSO and does not require immobilization or labeling, therefore allowing binding interactions to be characterized in the native state. BSI has the potential for reducing labor costs, sample consumption, and assay time while providing enhanced reliability over existing techniques. PMID:20972990

  10. Constant-distance mode scanning potentiometry. 1. Visualization of calcium carbonate dissolution in aqueous solution.

    PubMed

    Etienne, Mathieu; Schulte, Albert; Mann, Stefan; Jordan, Guntram; Dietzel, Irmgard D; Schuhmann, Wolfgang

    2004-07-01

    Constant-distance mode scanning potentiometry was established by integrating potentiometric microsensors as ion-selective scanning probes into a SECM setup that was equipped with a piezoelectric shear force-based tip-to-sample distance control. The combination of specially designed micrometer-sized potentiometric tips with an advanced system for tip positioning allowed simultaneous acquisition of both topographic and potentiometric information at solid/liquid interfaces with high spatial resolution. The performance of the approach was evaluated by applying Ca(2+)-selective constant-distance mode potentiometry to monitor the dissolution of calcium carbonate occurring either at the (104) surface of calcite crystals or in proximity to the more complex surface of cross sections of a calcium carbonate shell of Mya arenaria exposed to slightly acidic aqueous solutions. Micrometer-scale heterogeneities in the apparent calcium activity profiles have successfully been resolved for both samples.

  11. Utilization of carbon nanotubes for the removal of rhodamine B dye from aqueous solutions.

    PubMed

    Kumar, Sandeep; Bhanjana, Gaurav; Jangra, Kavita; Dilbaghi, Neeraj; Umar, Ahmad

    2014-06-01

    Carbon nanotubes (CNTs) are attracting increasing research interest as promising adsorbents for harmful cations, anions, and other organic and inorganic impurities present in natural sources of water. This study examined the feasibility of removing Rhodamine B dye from aqueous solutions using multi walled carbon nanotubes (MWCNTs) synthesized by chemical vapor deposition (CVD) method. The effects of dye concentration, pH and contact time on adsorption of direct dye by CNTs were also evaluated. The study used the Langmuir and Temkin isotherms to describe equilibrium adsorption. Additionally, pseudo second-order model was adopted to evaluate experimental data and thereby elucidate the kinetic adsorption process. The adsorption percentage of dye increased as contact time increased. Conversely, the adsorption percentage of dye decreased as dye concentration increased. The pseudo second-order model best represented adsorption kinetics. The capacity of CNTs to adsorb Rhodamine B was 65-90% at different pH values.

  12. Dehydration and crystallization of amorphous calcium carbonate in solution and in air.

    PubMed

    Ihli, Johannes; Wong, Wai Ching; Noel, Elizabeth H; Kim, Yi-Yeoun; Kulak, Alexander N; Christenson, Hugo K; Duer, Melinda J; Meldrum, Fiona C

    2014-01-01

    The mechanisms by which amorphous intermediates transform into crystalline materials are poorly understood. Currently, attracting enormous interest is the crystallization of amorphous calcium carbonate, a key intermediary in synthetic, biological and environmental systems. Here we attempt to unify many contrasting and apparently contradictory studies by investigating this process in detail. We show that amorphous calcium carbonate can dehydrate before crystallizing, both in solution and in air, while thermal analyses and solid-state nuclear magnetic resonance measurements reveal that its water is present in distinct environments. Loss of the final water fraction--comprising less than 15% of the total--then triggers crystallization. The high activation energy of this step suggests that it occurs by partial dissolution/recrystallization, mediated by surface water, and the majority of the particle then crystallizes by a solid-state transformation. Such mechanisms are likely to be widespread in solid-state reactions and their characterization will facilitate greater control over these processes.

  13. Decontamination of adsorbed chemical warfare agents on activated carbon using hydrogen peroxide solutions.

    PubMed

    Osovsky, Ruth; Kaplan, Doron; Nir, Ido; Rotter, Hadar; Elisha, Shmuel; Columbus, Ishay

    2014-09-16

    Mild treatment with hydrogen peroxide solutions (3-30%) efficiently decomposes adsorbed chemical warfare agents (CWAs) on microporous activated carbons used in protective garments and air filters. Better than 95% decomposition of adsorbed sulfur mustard (HD), sarin, and VX was achieved at ambient temperatures within 1-24 h, depending on the H2O2 concentration. HD was oxidized to the nontoxic HD-sulfoxide. The nerve agents were perhydrolyzed to the respective nontoxic methylphosphonic acids. The relative rapidity of the oxidation and perhydrolysis under these conditions is attributed to the microenvironment of the micropores. Apparently, the reactions are favored due to basic sites on the carbon surface. Our findings suggest a potential environmentally friendly route for decontamination of adsorbed CWAs, using H2O2 without the need of cosolvents or activators.

  14. Macromolecular conformation in solution. Study of carbonic anhydrase by the positron annihilation technique.

    PubMed Central

    Handel, E D; Graf, G; Glass, J C

    1980-01-01

    The structural features of carbonic anhydrase (carbonate hydro-lyase; EC 4.2.1.1) in aqueous solution were probed by the positron annihilation technique. The data obtained under varying conditions of temperature, pH, and enzyme concentration were interpreted in terms of the free volume model. The change of enzymic activity with temperature is accompanied by a change in free volume of the protein. Upon thermal denaturation an irreversible change in free volume of the molecule occurred. At low temperatures the protein-water interactions were investigated. These results are discussed in terms of current concepts of structure-function relationships in proteins. This study shows the sensitivity of the positron annihilation method toward the structure of proteins related to their overall conformation and to the nature of bound water. PMID:6789901

  15. Decontamination of adsorbed chemical warfare agents on activated carbon using hydrogen peroxide solutions.

    PubMed

    Osovsky, Ruth; Kaplan, Doron; Nir, Ido; Rotter, Hadar; Elisha, Shmuel; Columbus, Ishay

    2014-09-16

    Mild treatment with hydrogen peroxide solutions (3-30%) efficiently decomposes adsorbed chemical warfare agents (CWAs) on microporous activated carbons used in protective garments and air filters. Better than 95% decomposition of adsorbed sulfur mustard (HD), sarin, and VX was achieved at ambient temperatures within 1-24 h, depending on the H2O2 concentration. HD was oxidized to the nontoxic HD-sulfoxide. The nerve agents were perhydrolyzed to the respective nontoxic methylphosphonic acids. The relative rapidity of the oxidation and perhydrolysis under these conditions is attributed to the microenvironment of the micropores. Apparently, the reactions are favored due to basic sites on the carbon surface. Our findings suggest a potential environmentally friendly route for decontamination of adsorbed CWAs, using H2O2 without the need of cosolvents or activators. PMID:25133545

  16. Utilization of carbon nanotubes for the removal of rhodamine B dye from aqueous solutions.

    PubMed

    Kumar, Sandeep; Bhanjana, Gaurav; Jangra, Kavita; Dilbaghi, Neeraj; Umar, Ahmad

    2014-06-01

    Carbon nanotubes (CNTs) are attracting increasing research interest as promising adsorbents for harmful cations, anions, and other organic and inorganic impurities present in natural sources of water. This study examined the feasibility of removing Rhodamine B dye from aqueous solutions using multi walled carbon nanotubes (MWCNTs) synthesized by chemical vapor deposition (CVD) method. The effects of dye concentration, pH and contact time on adsorption of direct dye by CNTs were also evaluated. The study used the Langmuir and Temkin isotherms to describe equilibrium adsorption. Additionally, pseudo second-order model was adopted to evaluate experimental data and thereby elucidate the kinetic adsorption process. The adsorption percentage of dye increased as contact time increased. Conversely, the adsorption percentage of dye decreased as dye concentration increased. The pseudo second-order model best represented adsorption kinetics. The capacity of CNTs to adsorb Rhodamine B was 65-90% at different pH values. PMID:24738392

  17. Carbon and Hydrogen Isotope Measurements of Alcohols and Organic Acids by Online Pyroprobe-GC-IRMS

    NASA Technical Reports Server (NTRS)

    Socki, Richard A.; Fu, Qi; Niles, Paul B.; Gibson, Everett K., Jr.

    2012-01-01

    The detection of methane in the atmosphere of Mars, combined with evidence showing widespread water-rock interaction during martian history, suggests that the production of methane on Mars may be the result of mineral surface-catalyzed CO2 and or CO reduction during Fisher-Tropsch Type (FTT) reactions. A better understanding of these reaction pathways and corresponding C and H isotope fractionations is critical to deciphering the synthesis of organic compounds produced under abiotic hydrothermal conditions. Described here is a technique for the extraction and analysis of both C and H isotopes from alcohols (C1-C4) and organic acids (C1-C6). This work is meant to provide a "proof of concept" for making meaningful isotope measurements on complex mixtures of solid-phase hydrocarbons and other intermediary products produced during high-temperature and high-pressure synthesis on mineral-catalyzed surfaces. These analyses are conducted entirely "on-line" utilizing a CDS model 5000 Pyroprobe connected to a Thermo Trace GC Ultra that is interfaced with a Thermo MAT 253 isotope ratio mass spectrometer operating in continuous flow mode. Also, this technique is designed to carry a split of the GC-separated product to a DSQ II quadrupole mass spectrometer as a means of making semi-quantitative compositional measurements. Therefore, both chemical and isotopic measurements can be carried out on the same sample.

  18. Adsorption of Reactive Red M-2BE dye from water solutions by multi-walled carbon nanotubes and activated carbon.

    PubMed

    Machado, Fernando M; Bergmann, Carlos P; Fernandes, Thais H M; Lima, Eder C; Royer, Betina; Calvete, Tatiana; Fagan, Solange B

    2011-09-15

    Multi-walled carbon nanotubes and powdered activated carbon were used as adsorbents for the successful removal of Reactive Red M-2BE textile dye from aqueous solutions. The adsorbents were characterised by infrared spectroscopy, N(2) adsorption/desorption isotherms and scanning electron microscopy. The effects of pH, shaking time and temperature on adsorption capacity were studied. In the acidic pH region (pH 2.0), the adsorption of the dye was favourable using both adsorbents. The contact time to obtain equilibrium at 298K was fixed at 1h for both adsorbents. The activation energy of the adsorption process was evaluated from 298 to 323K for both adsorbents. The Avrami fractional-order kinetic model provided the best fit to the experimental data compared with pseudo-first-order or pseudo-second-order kinetic adsorption models. For Reactive Red M-2BE dye, the equilibrium data were best fitted to the Liu isotherm model. Simulated dyehouse effluents were used to check the applicability of the proposed adsorbents for effluent treatment. PMID:21724329

  19. The relationship between the adhesion work, the wettability and composition of the surface layer in the systems polymer/aqueous solution of anionic surfactants and alcohol mixtures

    NASA Astrophysics Data System (ADS)

    Zdziennicka, Anna; Jańczuk, Bronisław

    2010-11-01

    Measurements of advancing contact angle ( θ) were carried out on polytetrafluoroethylene (PTFE) and polymethylmethacrylate (PMMA) for aqueous solution of sodium dodecyl sulfate (SDDS) mixtures with methanol, ethanol and propanol in the range of SDDS concentration from 10 -5 to 10 -2 M, and for sodium hexadecyl sulfonate (SHS) with the same alcohols at the SHS concentration ranging from 10 -5 to 8 × 10 -4 M at 293 K. The concentration of methanol, ethanol and propanol used for measurements varied from 0 to 21.1, 11.97 and 6.67 M, respectively. On the basis of the contact angles the critical surface tension of PTFE and PMMA wetting was determined by using for this purpose the relationship between the adhesion and the surface tension and cos θ and surface tension both at constant alcohol and surfactant concentration, respectively. The obtained contact angles were also used in the Young Dupre' equation for calculations of the adhesion work of aqueous solution of mixtures of anionic surfactants and short chain alcohols to PTFE and PMMA surface. The adhesion work calculated in this way was compared to that of the particular components of aqueous solution to these surfaces determined on the basis of the surface tension components and parameters of the surface tension of the surface active agents, water, PTFE and PMMA from van Oss et al. equation. The calculated adhesion work was discussed in the light of the concentration of surface active agents at polymer-water and water-air interface determined from Lucassen-Reynders, Gibbs and Guggenheim-Adam equations.

  20. A Hydro-mechanical Model and Analytical Solutions for Geomechanical Modeling of Carbon Dioxide Geological Sequestration

    SciTech Connect

    Xu, Zhijie; Fang, Yilin; Scheibe, Timothy D.; Bonneville, Alain

    2012-05-15

    We present a hydro-mechanical model for geological sequestration of carbon dioxide. The model considers the poroelastic effects by taking into account the coupling between the geomechanical response and the fluid flow in greater detail. The simplified hydro-mechanical model includes the geomechanical part that relies on the linear elasticity, while the fluid flow is based on the Darcy’s law. Two parts were coupled using the standard linear poroelasticity. Analytical solutions for pressure field were obtained for a typical geological sequestration scenario. The model predicts the temporal and spatial variation of pressure field and effects of permeability and elastic modulus of formation on the fluid pressure distribution.

  1. Carbonized material adsorbents for the removal of mercury from aqueous solutions

    SciTech Connect

    1996-10-01

    Charcoal in itself is porous making it an excellent material for activated charcoal manufacture. However, few studies have been conducted in harnessing its potential for adsorption purposes, especially in water treatment. This paper describes the possibility of utilizing charcoal materials from Sugi (Cryptomeria japonica) for adsorbing heavy metals like mercury from aqueous solutions of different concentrations. The effect of soaking time, pore analyses and chemical properties on the adsorption capabilities of the carbonized materials were discussed. The pH value and chemical oxygen demand (COD) monitored during the soaking period were also described.

  2. Gravitation-dependent, thermally-induced self-diffraction in carbon nanotube solutions.

    PubMed

    Ji, Wei; Chen, Weizhe; Lim, Sanhua; Lin, Jianyi; Guo, Zhixin

    2006-10-01

    We report the observation of thermally-induced self-diffraction in carbon nanotube (CNT) solutions under the influence of the gravity. We present a theoretical model in which CNTs are assumed to obey the Boltzmman distribution law. Under the approximations of small temperature rise and a very narrow distribution of CNT masses, the model simulation is consistent with the data measured at low laser powers. An immediate application of such a gravitation-dependent characteristic is the optical measurement for molecular weights of CNTs.

  3. Adsorption of alkenyl succinic anhydride from solutions in carbon tetrachloride on a fine magnetite surface

    NASA Astrophysics Data System (ADS)

    Balmasova, O. V.; Ramazanova, A. G.; Korolev, V. V.

    2016-06-01

    The adsorption of alkenyl succinic anhydride from a solution in carbon tetrachloride on a fine magnetite surface at a temperature of 298.15 K is studied using fine magnetite, which forms the basis of magnetic fluids, as the adsorbent. An adsorption isotherm is recorded and interpreted in terms of the theory of the volume filling of micropores (TVFM). Adsorption process parameters are calculated on the basis of the isotherm. It is shown that at low equilibrium concentrations, the experimental adsorption isotherm is linear in the TVFM equation coordinates.

  4. Handwashing compliance in a French university hospital: new perspective with the introduction of hand-rubbing with a waterless alcohol-based solution.

    PubMed

    Girou, E; Oppein, F

    2001-08-01

    The baseline compliance with handwashing in a French university hospital was as low as the compliance rates reported in other countries, i.e., less than 50%. By introducing the use of hand-rubbing with an alcoholic solution, as a substitution method for both handwashing with soap and handwashing with an antiseptic agent, we significantly improved hand-cleansing compliance. Despite these encouraging results, mainly due to the accessibility of these non-aqueous products, three major obstacles remain before a wide acceptance by healthcare workers: distrust in terms of efficacy, distrust in terms of skin tolerance and lack of knowledge on hand-cleansing indications.

  5. Handwashing compliance in a French university hospital: new perspective with the introduction of hand-rubbing with a waterless alcohol-based solution.

    PubMed

    Girou, E; Oppein, F

    2001-08-01

    The baseline compliance with handwashing in a French university hospital was as low as the compliance rates reported in other countries, i.e., less than 50%. By introducing the use of hand-rubbing with an alcoholic solution, as a substitution method for both handwashing with soap and handwashing with an antiseptic agent, we significantly improved hand-cleansing compliance. Despite these encouraging results, mainly due to the accessibility of these non-aqueous products, three major obstacles remain before a wide acceptance by healthcare workers: distrust in terms of efficacy, distrust in terms of skin tolerance and lack of knowledge on hand-cleansing indications. PMID:11759028

  6. Removal of trihalomethanes from aqueous solution through armchair carbon nanotubes: a molecular dynamics study.

    PubMed

    Azamat, Jafar; Khataee, Alireza; Joo, Sang Woo; Yin, Binfeng

    2015-04-01

    Molecular dynamics simulations were performed to investigate the removal of trihalomethanes (THMs) including CH3Cl, CH2Cl2 and CHCl3 from aqueous solutions by armchair carbon nanotubes (CNTs) under induced pressure. The studied system involved the armchair CNTs embedded between two graphene sheets with an aqueous solution of THMs in the simulation box. An external pressure was applied to the system along the z-axis of the simulation box. Six types of armchair CNTs with different diameter were used in this work, included (4,4), (5,5), (6,6), (7,7), (8,8) and (9,9) CNTs. The results of molecular dynamics simulation display that the armchair CNTs behave differently relative to THMs and water molecules. The permeation of THMs and water molecules through the armchair CNTs was dependent on the diameter of CNTs and the applied pressure.

  7. Synthesis of finely divided molybdenum sulfide nanoparticles in propylene carbonate solution

    NASA Astrophysics Data System (ADS)

    Afanasiev, Pavel

    2014-05-01

    Molybdenum sulfide nanoparticles have been prepared from the reflux solution reaction involving ammonium heptamolybdate and elemental sulfur in propylene carbonate. Addition to the reaction mixture of starch as a natural capping agent leads to lesser agglomeration and smaller size of the particles. Nanoparticles of MoSx (x≈4) of 10-30 nm size are highly divided and form stable colloidal suspensions in organic solvents. Mo K edge EXAFS of the amorphous materials shows rapid exchange of oxygen to sulfur in the molybdenum coordination sphere during the solution reaction. Thermal treatment of the amorphous sulfides MoSx under nitrogen or hydrogen flow at 400 °C allows obtaining mesoporous MoS2 materials with very high pore volume and specific surface area, up to 0.45 cm3/g and 190 m2/g, respectively. The new materials show good potential for the application as unsupported hydrotreating catalysts.

  8. Carbon dioxide removal from flue gases by absorption/ desorption in aqueous diethanolamine solutions.

    PubMed

    Kierzkowska-Pawlak, Hanna; Chacuk, Andrzej

    2010-08-01

    The carbon dioxide (CO2) desorption rate from CO2- loaded aqueous diethanolamine (DEA) solutions was measured using a stirred cell with a flat gas-liquid interface. The measurements were performed in the temperature range of 293.15-313.15 K and an amine concentration range of 10-20% mass DEA. Measurements were based on a semibatch isothermal absorption of the gas until the equilibrium state was reached, followed by desorption, which was initiated by the pressure release in the system. A simplified mass transfer model based on the film theory coupled with CO2, mass balance was developed to interpret the experimental data. On the basis of the proposed model, the initial mass transfer rates were calculated from the experimental results. The calculated initial desorption rates enabled estimation of the enhancement factor for CO2 mass transfer from aqueous DEA solutions. Analysis of the experimental data showed that desorption took place in the diffusive mass transfer regime.

  9. Variation in assimilable organic carbon formation during chlorination of Microcystis aeruginosa extracellular organic matter solutions.

    PubMed

    Sun, Xingbin; Yuan, Ting; Ni, Huishan; Li, Yanpeng; Hu, Yang

    2016-07-01

    This study investigated the chlorination of Microcystis aeruginosa extracellular organic matter (EOM) solutions under different conditions, to determine how the metabolites produced by these organisms affect water safety and the formation of assimilable organic carbon (AOC). The effects of chlorine dosages, coagulant dosage, reaction time and temperature on the formation of AOC were investigated during the disinfection of M.aeruginosa metabolite solutions. The concentration of AOC followed a decreasing and then increasing pattern with increasing temperature and reaction time. The concentration of AOC decreased and then increased with increasing chlorination dosage, followed by a slight decrease at the highest level of chlorination. However, the concentration of AOC decreased continuously with increasing coagulant dosage. The formation of AOC can be suppressed under appropriate conditions. In this study, chlorination at 4mg/L, combined with a coagulant dose of 40mg/L at 20°C over a reaction time of 12hr, produced the minimum AOC. PMID:27372113

  10. Corrosion Inhibition of Carbon Steel by New Thiophene Azo Dye Derivatives in Acidic Solution

    NASA Astrophysics Data System (ADS)

    El-Haddad, Mahmoud N.; Fouda, A. S.; Mostafa, H. A.

    2013-08-01

    Inhibition of carbon steel corrosion in 2 M hydrochloric acid (HCl) solution by thiophene azo dye derivatives were studied using weight loss, electrochemical frequency modulation (EFM), and atomic absorption techniques. The experimental data suggest that the inhibition efficiency increases with increasing inhibitors concentration in presence of 103 μM potassium iodide (KI). This is due to synergistic effect. Thus, the experimental results suggested that the presence of these anions in the solution stabilized the adsorption of inhibitors molecules on the metal surface and improved the inhibition efficiency. The results of EFM experiments are a spectrum of current response as a function of frequency. The corrosion rate and Tafel parameters can be obtained with measurement by analyzing the harmonic frequencies. The adsorption of the inhibitors on metal surface obeys the Langmuir adsorption isotherm. The surface of metal examined using Fourier transform infrared and ultraviolet spectroscopy. Quantum chemical calculations were carried out and relations between computed parameters and experimental inhibition efficiency were discussed.

  11. Analytical solutions to dissolved contaminant plume evolution with source depletion during carbon dioxide storage

    NASA Astrophysics Data System (ADS)

    Yang, Yong; Liu, Yongzhong; Yu, Bo; Ding, Tian

    2016-06-01

    Volatile contaminants may migrate with carbon dioxide (CO2) injection or leakage in subsurface formations, which leads to the risk of the CO2 storage and the ecological environment. This study aims to develop an analytical model that could predict the contaminant migration process induced by CO2 storage. The analytical model with two moving boundaries is obtained through the simplification of the fully coupled model for the CO2-aqueous phase -stagnant phase displacement system. The analytical solutions are confirmed and assessed through the comparison with the numerical simulations of the fully coupled model. Then, some key variables in the analytical solutions, including the critical time, the locations of the dual moving boundaries and the advance velocity, are discussed to present the characteristics of contaminant migration in the multi-phase displacement system. The results show that these key variables are determined by four dimensionless numbers, Pe, RD, Sh and RF, which represent the effects of the convection, the dispersion, the interphase mass transfer and the retention factor of contaminant, respectively. The proposed analytical solutions could be used for tracking the migration of the injected CO2 and the contaminants in subsurface formations, and also provide an analytical tool for other solute transport in multi-phase displacement system.

  12. Adsorptive removal of aniline by granular activated carbon from aqueous solutions with catechol and resorcinol.

    PubMed

    Suresh, S; Srivastava, V C; Mishrab, I M

    2012-01-01

    In the present paper, the removal of aniline by adsorption process onto granular activated carbon (GAC) is reported from aqueous solutions containing catechol and resorcinol separately. The Taguchi experimental design was applied to study the effect of such parameters as the initial component concentrations (C(0,i)) of two solutes (aniline and catechol or aniline and resorcinol) in the solution, temperature (T), adsorbent dosage (m) and contact time (t). The L27 orthogonal array consisting of five parameters each with three levels was used to determine the total amount of solutes adsorbed on GAC (q(tot), mmol/g) and the signal-to-noise ratio. The analysis of variance (ANOVA) was used to determine the optimum conditions. Under these conditions, the ANOVA shows that m is the most important parameter in the adsorption process. The most favourable levels of process parameters were T = 303 K, m = 10 g/l and t = 660 min for both the systems, qtot values in the confirmation experiments carried out at optimum conditions were 0.73 and 0.95 mmol/g for aniline-catechol and aniline-resorcinol systems, respectively.

  13. Analytical solutions to dissolved contaminant plume evolution with source depletion during carbon dioxide storage.

    PubMed

    Yang, Yong; Liu, Yongzhong; Yu, Bo; Ding, Tian

    2016-06-01

    Volatile contaminants may migrate with carbon dioxide (CO2) injection or leakage in subsurface formations, which leads to the risk of the CO2 storage and the ecological environment. This study aims to develop an analytical model that could predict the contaminant migration process induced by CO2 storage. The analytical model with two moving boundaries is obtained through the simplification of the fully coupled model for the CO2-aqueous phase -stagnant phase displacement system. The analytical solutions are confirmed and assessed through the comparison with the numerical simulations of the fully coupled model. Then, some key variables in the analytical solutions, including the critical time, the locations of the dual moving boundaries and the advance velocity, are discussed to present the characteristics of contaminant migration in the multi-phase displacement system. The results show that these key variables are determined by four dimensionless numbers, Pe, RD, Sh and RF, which represent the effects of the convection, the dispersion, the interphase mass transfer and the retention factor of contaminant, respectively. The proposed analytical solutions could be used for tracking the migration of the injected CO2 and the contaminants in subsurface formations, and also provide an analytical tool for other solute transport in multi-phase displacement system.

  14. Curing of Furfuryl Alcohol-Impregnated Parts

    NASA Technical Reports Server (NTRS)

    Lawton, J. W.; Brayden, T. H.

    1983-01-01

    Delamination problem in reinforced carbon/carbon parts impregnated with oxalic acid-catalyzed furfuryl alcohol overcome by instituting two additional quality-control tests on alcohol and by changing curing conditions.

  15. CO2 Absorption in an Alcoholic Solution of Heavily Hindered Alkanolamine: Reaction Mechanism of 2-(tert-Butylamino)ethanol with CO2 Revisited.

    PubMed

    Xie, Hong-Bin; Wei, Xiaoxuan; Wang, Pan; He, Ning; Chen, Jingwen

    2015-06-18

    To advance the optimal design of amines for postcombustion CO2 capture, a sound mechanistic understanding of the chemical process of amines with good CO2 capture performance is advantageous. A sterically hindered alkanolamine, 2-(tert-butylamino)ethanol (TBAE), in ethylene glycol (EG) solution was recently reported to have better CO2 capture performance and unusual reactivity toward CO2, in comparison with those of the prototypical alkanolamines. However, the reaction mechanism of TBAE with CO2 in EG solution is unclear. Here, various quantum chemistry methods were employed to probe the reaction mechanism of TBAE with CO2 in EG and aqueous solution. Six reaction pathways involving three kinds of possible reactive centers of TBAE solution were considered. The results indicated that the formation of anionic hydroxyethyl carbonate by the attack of -OH of EG on CO2 is the most favorable, which is confirmed by complementary high-resolution mass spectrum experiments. This clarified that the speculated zwitterionic carbonate species is not the main product in EG solution. The reaction process of TBAE in aqueous solution is similar to that in EG solution, leading to bicarbonate, which agrees with experimental observations. On the basis of the unveiled reaction mechanisms of TBAE + CO2, the role of the key tert-butyl functional group of TBAE was revealed. PMID:25993508

  16. Na⁺-functionalized carbon quantum dots: a new draw solute in forward osmosis for seawater desalination.

    PubMed

    Guo, Chun Xian; Zhao, Dieling; Zhao, Qipeng; Wang, Peng; Lu, Xianmao

    2014-07-14

    A new type of biocompatible draw solute, Na(+)-functionalized carbon quantum dots (Na_CQDs) with ultra-small size and rich ionic species, in forward osmosis (FO) is developed for seawater desalination. The aqueous dispersion of Na_CQDs demonstrates a high osmotic pressure, which allows high FO water flux and negligible reverse solute permeation.

  17. High-Strength Single-Walled Carbon Nanotube/Permalloy Nanoparticle/Poly(vinyl alcohol) Multifunctional Nanocomposite Fiber.

    PubMed

    Zhou, Gengheng; Wang, Yi-Qi; Byun, Joon-Hyung; Yi, Jin-Woo; Yoon, Sang-Su; Cha, Hwa-Jin; Lee, Jea-Uk; Oh, Youngseok; Jung, Byung-Mun; Moon, Ho-Jun; Chou, Tsu-Wei

    2015-11-24

    Magnetic nanocomposite fibers are a topic of intense research due to their potential breakthrough applications such as smart magnetic-field-response devices and electromagnetic interference (EMI) shielding. However, clustering of nanoparticles in a polymer matrix is a recognized challenge for obtaining a property-controllable nanocomposite fiber. Another challenge is that the strength and ductility of the nanocomposite fiber decrease significantly with increased weight loading of magnetic nanoparticles in the fiber. Here, we report high-strength single-walled carbon nanotube (SWNT)/permalloy nanoparticle (PNP)/poly(vinyl alcohol) multifunctional nanocomposite fibers fabricated by wet spinning. The weight loadings of SWNTs and PNPs in the fiber were as high as 12.0 and 38.0%, respectively. The tensile strength of the fiber was as high as 700 MPa, and electrical conductivity reached 96.7 S m(-1). The saturation magnetization (Ms) was as high as 24.8 emu g(-1). The EMI attenuation of a fabric woven from the prepared fiber approached 100% when tested with electromagnetic waves with a frequency higher than 6 GHz. The present study demonstrates that a magnetic-field-response device can be designed using the fabricated multifunctional nanocomposite fiber. PMID:26431310

  18. Laboratory differential simulation design method of pressure absorbers for carbonization of phenolate solution by carbon dioxide in coal-tar processing

    SciTech Connect

    Linek, V.; Sinkule, J.; Moucha, T.; Rejl, J.F.

    2009-01-15

    A laboratory differential simulation method is used for the design of carbonization columns at coal-tar processing in which phenols are regenerated from phenolate solution by carbon dioxide absorption. The design method is based on integration of local absorption rates of carbon dioxide along the column. The local absorption rates into industrial phenolate mixture are measured in a laboratory model contactor for various compositions of the gas and liquid phases under the conditions that ensure the absorption rates in the laboratory absorber simulate the local rates in the industrial column. On the bases of the calculations, two-step carbonization columns were designed for 30000 t/year of the phenolate solution treatment by carbon dioxide. The absorption proceeds at higher pressure of 500 kPa and temperatures from 50 to 65 C, pure carbon dioxide is used and toluene is added. These conditions have the following favourable effects: (I) significant size reduction of the columns, (ii) it is possible to process more concentrated solutions without danger of silting the columns by crystallization of NaHCO{sub 3} on the packing. (iii) small amount of inert gas is released, (iv) lower alkalinity and better separability of the organic phase (phenols with toluene) from water phase (soda or bicarbonate solution) in separators.

  19. Characterization of platinum catalyst supported on carbon nanoballs prepared by solution plasma processing

    SciTech Connect

    Ichin, Yoshimichi; Mitamura, Koji; Saito, Nagahiro; Takai, Osamu

    2009-07-15

    In order to improve the energy-conversion efficiency in fuel cells, the authors loaded Pt nanoparticles on carbon nanoballs (CNBs) by using solution plasma processing (SPP) involving CNB and Pt ion with a protection group. In this study, we employed poly(vinylpyrrolidone) (PVP) or sodium dodecyl sulfate (SDS) to prepare Pt nanoparticles supported on CNB (Pt/CNB) by the SPP, and the electrochemical properties as a catalyst was evaluated by cyclic voltammetry. The carbon nanoballs were prepared by thermal decomposition process of ethylene and hydrogen gases. Color of the solution changed from yellow to dark brown as synthesis time. This change indicates the improvement of dispersibility of CNB. Moreover, transmission electron microscopy images and elemental mapping images showed the Pt nanoparticles supported on CNB. A catalytic activity of the Pt/CNB in use of SDS was shown to be higher than the Pt/CNB prepared with PVP system. The SDS-containing Pt/CNB also showed the higher activity than that obtained by the conventional method.

  20. Degradation of triclosan in aqueous solution by dielectric barrier discharge plasma combined with activated carbon fibers.

    PubMed

    Xin, Lu; Sun, Yabing; Feng, Jingwei; Wang, Jian; He, Dong

    2016-02-01

    The degradation of triclosan (TCS) in aqueous solution by dielectric barrier discharge (DBD) plasma with activated carbon fibers (ACFs) was investigated. In this study, ACFs and DBD plasma coexisted in a planar DBD plasma reactor, which could synchronously achieve degradation of TCS, modification and in situ regeneration of ACFs, enhancing the effect of recycling of ACFs. The properties of ACFs before and after modification by DBD plasma were characterized by BET and XPS. Various processing parameters affecting the synergetic degradation of TCS were also investigated. The results exhibited excellent synergetic effects in DBD plasma-ACFs system on TCS degradation. The degradation efficiency of 120 mL TCS with initial concentration of 10 mg L(-1) could reach 93% with 1 mm thick ACFs in 18 min at input power of 80 W, compared with 85% by single DBD plasma. Meanwhile, the removal rate of total organic carbon increased from 12% at pH 6.26-24% at pH 3.50. ACFs could ameliorate the degradation efficiency for planar DBD plasma when treating TCS solution at high flow rates or at low initial concentrations. A possible degradation pathway of TCS was investigated according to the detected intermediates, which were identified by liquid chromatography-hybrid quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) combined with theoretical calculation of Gaussian 09 program. PMID:26421625

  1. Degradation of triclosan in aqueous solution by dielectric barrier discharge plasma combined with activated carbon fibers.

    PubMed

    Xin, Lu; Sun, Yabing; Feng, Jingwei; Wang, Jian; He, Dong

    2016-02-01

    The degradation of triclosan (TCS) in aqueous solution by dielectric barrier discharge (DBD) plasma with activated carbon fibers (ACFs) was investigated. In this study, ACFs and DBD plasma coexisted in a planar DBD plasma reactor, which could synchronously achieve degradation of TCS, modification and in situ regeneration of ACFs, enhancing the effect of recycling of ACFs. The properties of ACFs before and after modification by DBD plasma were characterized by BET and XPS. Various processing parameters affecting the synergetic degradation of TCS were also investigated. The results exhibited excellent synergetic effects in DBD plasma-ACFs system on TCS degradation. The degradation efficiency of 120 mL TCS with initial concentration of 10 mg L(-1) could reach 93% with 1 mm thick ACFs in 18 min at input power of 80 W, compared with 85% by single DBD plasma. Meanwhile, the removal rate of total organic carbon increased from 12% at pH 6.26-24% at pH 3.50. ACFs could ameliorate the degradation efficiency for planar DBD plasma when treating TCS solution at high flow rates or at low initial concentrations. A possible degradation pathway of TCS was investigated according to the detected intermediates, which were identified by liquid chromatography-hybrid quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) combined with theoretical calculation of Gaussian 09 program.

  2. Alcoholism, Alcohol, and Drugs

    ERIC Educational Resources Information Center

    Rubin, Emanuel; Lieber, Charles S.

    1971-01-01

    Describes research on synergistic effects of alcohol and other drugs, particularly barbiturates. Proposes biochemical mechanisms to explain alcoholics' tolerance of other drugs when sober, and increased sensitivity when drunk. (AL)

  3. A comparative study for the removal of hexavalent chromium from aqueous solution by agriculture wastes' carbons.

    PubMed

    Bansal, Manjeet; Singh, Diwan; Garg, V K

    2009-11-15

    This paper reports the feasibility of using agricultural waste and timber industry waste carbons to remove Cr(VI) from synthetic wastewater under different experimental conditions. For this, rice husk and saw dust have been used as adsorbent after sulphuric acid treatment. Effect of various process parameters, namely, pH, adsorbent dose, initial chromium concentration and contact time has been studied in batch systems. Maximum metal removal was observed at pH 2.0. The efficiencies of rice husk carbon (RHC) and saw dust carbon (SDC) for Cr(VI) removal were 91.75% and 94.33%, respectively for aqueous solutions (250 mg L(-1)) at 20 g L(-1) adsorbent dose. The experimental data was analyzed using Freundlich, Langmuir, Dubinin-Redushkevich (D-R) and Temkin isotherm models. It was found that Langmuir, D-R and Temkin models fitted well. The results revealed that the hexavalent chromium is considerably adsorbed on RHC and SDC and it could be an economical method for the removal of hexavalent chromium from aqueous systems. FTIR and SEM of the adsorbents were recorded in native and Cr(VI)-loaded state to explore the number and position of various functional groups available for Cr(VI) binding onto studied adsorbents and changes in adsorbent surface morphology. The surface area of RHC and SDC was 1.12 and 1.16 m(2)g(-1), respectively. PMID:19553015

  4. Cryogenic-temperature electron microscopy direct imaging of carbon nanotubes and graphene solutions in superacids.

    PubMed

    Kleinerman, O; Parra-Vasquez, A Nicholas G; Green, M J; Behabtu, N; Schmidt, J; Kesselman, E; Young, C C; Cohen, Y; Pasquali, M; Talmon, Y

    2015-07-01

    Cryogenic electron microscopy (cryo-EM) is a powerful tool for imaging liquid and semiliquid systems. While cryogenic transmission electron microscopy (cryo-TEM) is a standard technique in many fields, cryogenic scanning electron microscopy (cryo-SEM) is still not that widely used and is far less developed. The vast majority of systems under investigation by cryo-EM involve either water or organic components. In this paper, we introduce the use of novel cryo-TEM and cryo-SEM specimen preparation and imaging methodologies, suitable for highly acidic and very reactive systems. Both preserve the native nanostructure in the system, while not harming the expensive equipment or the user. We present examples of direct imaging of single-walled, multiwalled carbon nanotubes and graphene, dissolved in chlorosulfonic acid and oleum. Moreover, we demonstrate the ability of these new cryo-TEM and cryo-SEM methodologies to follow phase transitions in carbon nanotube (CNT)/superacid systems, starting from dilute solutions up to the concentrated nematic liquid-crystalline CNT phases, used as the 'dope' for all-carbon-fibre spinning. Originally developed for direct imaging of CNTs and graphene dissolution and self-assembly in superacids, these methodologies can be implemented for a variety of highly acidic systems, paving a way for a new field of nonaqueous cryogenic electron microscopy. PMID:25818279

  5. Cryogenic-temperature electron microscopy direct imaging of carbon nanotubes and graphene solutions in superacids.

    PubMed

    Kleinerman, O; Parra-Vasquez, A Nicholas G; Green, M J; Behabtu, N; Schmidt, J; Kesselman, E; Young, C C; Cohen, Y; Pasquali, M; Talmon, Y

    2015-07-01

    Cryogenic electron microscopy (cryo-EM) is a powerful tool for imaging liquid and semiliquid systems. While cryogenic transmission electron microscopy (cryo-TEM) is a standard technique in many fields, cryogenic scanning electron microscopy (cryo-SEM) is still not that widely used and is far less developed. The vast majority of systems under investigation by cryo-EM involve either water or organic components. In this paper, we introduce the use of novel cryo-TEM and cryo-SEM specimen preparation and imaging methodologies, suitable for highly acidic and very reactive systems. Both preserve the native nanostructure in the system, while not harming the expensive equipment or the user. We present examples of direct imaging of single-walled, multiwalled carbon nanotubes and graphene, dissolved in chlorosulfonic acid and oleum. Moreover, we demonstrate the ability of these new cryo-TEM and cryo-SEM methodologies to follow phase transitions in carbon nanotube (CNT)/superacid systems, starting from dilute solutions up to the concentrated nematic liquid-crystalline CNT phases, used as the 'dope' for all-carbon-fibre spinning. Originally developed for direct imaging of CNTs and graphene dissolution and self-assembly in superacids, these methodologies can be implemented for a variety of highly acidic systems, paving a way for a new field of nonaqueous cryogenic electron microscopy.

  6. Removal of nickel(II) from aqueous solution using Citrus Limettioides peel and seed carbon.

    PubMed

    Sudha, R; Srinivasan, K; Premkumar, P

    2015-07-01

    The agricultural wastes like Citrus Limettioides peel and seed to be suitable precursor for the preparation of carbon [Citrus Limettioides peel carbon (CLPC) and seed carbon (CLSC)] has been explored in the present work, utilizing sulfuric acid as the activating agent. Adsorption studies were performed by varying contact time, solution pH, adsorbent dose and temperature. The equilibrium time for Ni(II) ions was determined as 4h and optimal pH was 4-7. Surface morphology and functionality of the CLPC and CLSC were characterized by SEM, EDX and FT-IR. The experimental data were analysed using the Freundlich, Langmuir, Temkin, Redlich-Peterson, Sips and Dubinin-Radushkevich adsorption isotherm equations using nonlinear regression analysis. Equilibrium data were found to fit well in the Langmuir isotherm, which confirmed the monolayer coverage of Ni(II) ions. The Langmuir monolayer adsorption capacity of CLPC and CLSC was found to be 38.46 and 35.54 mg/g. The thermodynamic parameters indicated that the adsorption process was spontaneous and exothermic in nature. The kinetic data followed pseudo-second order model with film diffusion process. The adsorbents were tested with Ni(II) plating wastewater in connection with the reuse and selectivity of the adsorbents. PMID:25841067

  7. Carbonation of municipal solid waste incineration electrostatic precipitator fly ashes in solution.

    PubMed

    De Boom, Aurore; Aubert, Jean-Emmanuel; Degrez, Marc

    2014-05-01

    Carbonation was applied to a Pb- and Zn-contaminated fraction of municipal solid waste incineration electrofilter fly ashes in order to reduce heavy metal leaching. Carbonation tests were performed in solution, by Na2CO3 addition or CO2 bubbling, and were compared with washing (with water only). The injection of CO2 during the washing did not modify the mineralogy, but the addition of Na2CO3 induced the reaction with anhydrite, forming calcite. Microprobe analyses showed that Pb and Zn contamination was rather diffuse and that the various treatments had no effect on Pb and Zn speciation in the residues. The leaching tests indicated that carbonation using Na2CO3 was successful because it gave a residue that could be considered as non-hazardous material. With CO2 bubbling, Pb and Zn leaching was strongly decreased compared with material washed with water alone, but the amount of chromium extracted became higher than the non-hazardous waste limits for landfilling.

  8. Sorption of lanthanum and erbium from aqueous solution by activated carbon prepared from rice husk.

    PubMed

    Awwad, N S; Gad, H M H; Ahmad, M I; Aly, H F

    2010-12-01

    A biomass agricultural waste material, rice husk (RH) was used for preparation of activated carbon by chemical activation using phosphoric acid. The effect of various factors, e.g. time, pH, initial concentration and temperature of carbon on the adsorption capacity of lanthanum and erbium was quantitatively determined. It was found that the monolayer capacity is 175.4 mg g(-1) for La(III) and 250 mg g(-1) for Er(III). The calculated activation energy of La(III) adsorption on the activated carbon derived from rice husk was equal to 5.84 kJ/mol while it was 3.6 kJ/mol for Er(III), which confirm that the reaction is mainly particle-diffusion-controlled. The kinetics of sorption was described by a model of a pseudo-second-order. External diffusion and intra-particular diffusion were examined. The experimental data show that the external diffusion and intra-particular diffusion are significant in the determination of the sorption rate. Therefore, the developed sorbent is considered as a better replacement technology for removal of La(III) and Er(III) ions from aqueous solution due to its low-cost and good efficiency, fast kinetics, as well as easy to handle and thus no or small amount of secondary sludge is obtained in this application.

  9. Ultrasound-assisted adsorption of 4-dodecylbenzene sulfonate from aqueous solutions by corn cob activated carbon.

    PubMed

    Milenković, D D; Bojić, A Lj; Veljković, V B

    2013-05-01

    This study was aimed at removal of 4-dodecylbenzene sulfonate (DBS) ions from aqueous solutions by ultrasound-assisted adsorption onto the carbonized corn cob (AC). The main attention was focused on modeling the equilibrium and kinetics of adsorption of DBS onto the AC. The AC was prepared from ground dried corn cob by carbonization and activation by carbon dioxide at 880°C for 2h in a rotary furnace. The adsorption isotherm data were fitted by the Langmuir model in both the absence and the presence of ultrasound (US). The maximum adsorption capacities of the adsorbent for DBS, calculated from the Langmuir isotherms, were 29.41mg/g and 27.78mg/g in the presence of US and its absence, respectively. The adsorption process in the absence and the presence of US obeyed the pseudo second-order kinetics. The intraparticular diffusion model indicated that the adsorption of DBS ions on the AC was diffusion controlled as well as that US promoted intraparticular diffusion. The ΔG° values, -24.03kJ/mol, -25.78kJ/mol and -27.78kJ/mol, were negative at all operating temperatures, verifying that the adsorption of DBS ions was spontaneous and thermodynamically favorable. The positive value of ΔS°=187J/molK indicated the increased randomness at the adsorbent-adsorbate interface during the adsorption of DBS ions by the AC. PMID:23187067

  10. Rapid and sensitive determination of benzaldehyde arising from benzyl alcohol used as preservative in an injectable formulation solution using dispersive liquid-liquid microextraction followed by gas chromatography.

    PubMed

    Mashayekhi, Hossein Ali; Rezaee, Mohammad; Garmaroudi, Shirin Sadeghi; Montazeri, Naser; Ahmadi, Seyed Javad

    2011-01-01

    A rapid and sensitive method has been developed for the determination of benzaldehyde, a toxic oxidation product of the widely used preservative and co-solvent benzyl alcohol in injectable formulations of non-steroidal anti-inflammatory drugs, diclofenac, vitamin B-complex and Voltaren injection solutions by using dispersive liquid-liquid microextraction followed by gas chromatography. This method involves the use of an appropriate mixture of extraction solvent (43.0 µL 1,2-dichloroethane) and disperser solvent (1.0 mL acetonitrile) for the formation of a cloudy solution in a 5.0-mL aqueous sample containing benzaldehyde. The linear range was 1.0-1000 µg L(-1), and the limit of detection was 0.2 µg L(-1) for benzaldehyde.

  11. [Studies on carbonization of saccharides by using aqueous solution of various acids].

    PubMed

    Zhang, Xin; He, An-Qi; Kang, Ting-Guo; Xia, Jin-Ming; Weng, Shi-Fu; Xu, Yi-Zhuang; Wu, Jin-Guang

    2014-09-01

    The authors tried to establish an approach to use acids to convert biomass into a fuel with higher carbon content and lower oxygen content in a zero-energy-consumption fashion. Considering that biomass is composed of monosaccharide, we used aqueous solutions of variation acids including hydrochloric acid, sulfuric acid and perchloric acid to treat 2-deoxy-ribose and fructose at ambient temperature and pressure. Black substances were produced after a period of time when 2-deoxy-ribose and fructose were mixed with aqueous solutions containing 8 mol · L(-1) acids. The black substance was collected and characterized by using elemental analysis, Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Elemental analysis results indicate that the contents of carbon increases significantly in the black substances in comparison with 2-deoxy-ribose and fructose. Moreover, XPS results indicate that the content of oxygen in the black substance undergoes a significant decrease compared with pure 2-deoxy-ribose and fructose. In the XPS spectra, the is peaks of 2-deoxy-ribose, strong sub peak at 286. 05 eV, which is assigned to carbon linked to oxygen directly, dominate in the C is peak envelop. After treatment by HClO4, the peak decreased dramatically. This result also supports the conclusion that the content of oxygen in mono-saccharide is significantly reduced after treatment by acids. In the FTIR spectra of the black substances, strong peaks can be observed around 1 600 cm(-1), indicating that C==C bond is formed in the product. The above results suggest that treatments with acids may be developed as a new zero-energy-consumption approach to convert biomass in a new fuel with improved energy output efficiency. PMID:25532323

  12. [Studies on carbonization of saccharides by using aqueous solution of various acids].

    PubMed

    Zhang, Xin; He, An-Qi; Kang, Ting-Guo; Xia, Jin-Ming; Weng, Shi-Fu; Xu, Yi-Zhuang; Wu, Jin-Guang

    2014-09-01

    The authors tried to establish an approach to use acids to convert biomass into a fuel with higher carbon content and lower oxygen content in a zero-energy-consumption fashion. Considering that biomass is composed of monosaccharide, we used aqueous solutions of variation acids including hydrochloric acid, sulfuric acid and perchloric acid to treat 2-deoxy-ribose and fructose at ambient temperature and pressure. Black substances were produced after a period of time when 2-deoxy-ribose and fructose were mixed with aqueous solutions containing 8 mol · L(-1) acids. The black substance was collected and characterized by using elemental analysis, Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Elemental analysis results indicate that the contents of carbon increases significantly in the black substances in comparison with 2-deoxy-ribose and fructose. Moreover, XPS results indicate that the content of oxygen in the black substance undergoes a significant decrease compared with pure 2-deoxy-ribose and fructose. In the XPS spectra, the is peaks of 2-deoxy-ribose, strong sub peak at 286. 05 eV, which is assigned to carbon linked to oxygen directly, dominate in the C is peak envelop. After treatment by HClO4, the peak decreased dramatically. This result also supports the conclusion that the content of oxygen in mono-saccharide is significantly reduced after treatment by acids. In the FTIR spectra of the black substances, strong peaks can be observed around 1 600 cm(-1), indicating that C==C bond is formed in the product. The above results suggest that treatments with acids may be developed as a new zero-energy-consumption approach to convert biomass in a new fuel with improved energy output efficiency.

  13. Trends in soil solution dissolved organic carbon (DOC) concentrations across European forests

    NASA Astrophysics Data System (ADS)

    Camino-Serrano, Marta; Graf Pannatier, Elisabeth; Vicca, Sara; Luyssaert, Sebastiaan; Jonard, Mathieu; Ciais, Philippe; Guenet, Bertrand; Gielen, Bert; Peñuelas, Josep; Sardans, Jordi; Waldner, Peter; Etzold, Sophia; Cecchini, Guia; Clarke, Nicholas; Galić, Zoran; Gandois, Laure; Hansen, Karin; Johnson, Jim; Klinck, Uwe; Lachmanová, Zora; Lindroos, Antti-Jussi; Meesenburg, Henning; Nieminen, Tiina M.; Sanders, Tanja G. M.; Sawicka, Kasia; Seidling, Walter; Thimonier, Anne; Vanguelova, Elena; Verstraeten, Arne; Vesterdal, Lars; Janssens, Ivan A.

    2016-10-01

    Dissolved organic carbon (DOC) in surface waters is connected to DOC in soil solution through hydrological pathways. Therefore, it is expected that long-term dynamics of DOC in surface waters reflect DOC trends in soil solution. However, a multitude of site studies have failed so far to establish consistent trends in soil solution DOC, whereas increasing concentrations in European surface waters over the past decades appear to be the norm, possibly as a result of recovery from acidification. The objectives of this study were therefore to understand the long-term trends of soil solution DOC from a large number of European forests (ICP Forests Level II plots) and determine their main physico-chemical and biological controls. We applied trend analysis at two levels: (1) to the entire European dataset and (2) to the individual time series and related trends with plot characteristics, i.e., soil and vegetation properties, soil solution chemistry and atmospheric deposition loads. Analyses of the entire dataset showed an overall increasing trend in DOC concentrations in the organic layers, but, at individual plots and depths, there was no clear overall trend in soil solution DOC. The rate change in soil solution DOC ranged between -16.8 and +23 % yr-1 (median = +0.4 % yr-1) across Europe. The non-significant trends (40 %) outnumbered the increasing (35 %) and decreasing trends (25 %) across the 97 ICP Forests Level II sites. By means of multivariate statistics, we found increasing trends in DOC concentrations with increasing mean nitrate (NO3-) deposition and increasing trends in DOC concentrations with decreasing mean sulfate (SO42-) deposition, with the magnitude of these relationships depending on plot deposition history. While the attribution of increasing trends in DOC to the reduction of SO42- deposition could be confirmed in low to medium N deposition areas, in agreement with observations in surface waters, this was not the case in high N deposition areas. In

  14. Bond dissociation mechanism of ethanol during carbon nanotube synthesis via alcohol catalytic CVD technique: Ab initio molecular dynamics simulation

    NASA Astrophysics Data System (ADS)

    Oguri, Tomoya; Shimamura, Kohei; Shibuta, Yasushi; Shimojo, Fuyuki; Yamaguchi, Shu

    2014-03-01

    Dissociation of ethanol on a nickel cluster is investigated by ab initio molecular dynamics simulation to reveal the bond dissociation mechanism of carbon source molecules during carbon nanotube synthesis. C-C bonds in only CHxCO fragments are dissociated on the nickel cluster, whereas there is no preferential structure among the fragments for C-O bond dissociation. The dissociation preference is uncorrelated with the bond dissociation energy of corresponding bonds in freestanding molecules but is correlated with the energy difference between fragment molecules before and after dissociation on the nickel surface. Moreover, carbon-chain formation occurs after C-C bond dissociation in a continuous simulation. What determines the chirality of CNTs? What happens at the dissociation stage of carbon source molecules? Regarding the former question, many researchers have pointed out the good epitaxial relationship between a graphite network and a close-packed facet (i.e., fcc(1 1 1) or hcp(0 0 0 1)) of transition metals [17-19]. Therefore, the correlation between the chirality of CNTs and the angle of the step edge on metal (or metal carbide) surfaces has been closely investigated [20-22]. In association with this geometric matching, the epitaxial growth of graphene on Cu(1 1 1) and Ni(1 1 1) surfaces has recently been achieved via CCVD technique [23-25], which is a promising technique for the synthesis of large-area and monolayer graphene.Regarding the latter question, it is empirically known that the yield and quality of CNT products strongly depend on the choice of carbon source molecules and additives. For example, it is well known that the use of ethanol as carbon source molecules yields a large amount of SWNTs without amorphous carbons (called the alcohol CCVD (ACCVD) technique) compared with the CCVD process using hydrocarbons [4]. Moreover, the addition of a small amount of water dramatically enhances the activity and lifetime of the catalytic metal (called the

  15. Covalent cum noncovalent functionalizations of carbon nanotubes for effective reinforcement of a solution cast composite film.

    PubMed

    Yuan, Wei; Chan-Park, Mary B

    2012-04-01

    Although carbon nanotubes have impressive tensile properties, exploiting these properties in composites, especially those made by the common solution casting technique, seems to be elusive thus far. The reasons could be partly due to the poor nanotube dispersion and the weak nanotube/matrix interface. To solve this dual pronged problem, we combine noncovalent and covalent functionalizations of nanotubes in a single system by the design and application of a novel dispersant, hydroxyl polyimide-graft-bisphenol A diglyceryl acrylate (PI(OH)-BDA), and use them with epoxidized single-walled carbon nanotubes (O-SWNTs). Our novel PI(OH)-BDA dispersant functionalizes the nanotubes noncovalently to achieve good dispersion of the nanotubes because of the strong π-π interaction due to main chain and steric hindrance of the BDA side chain. PI(OH)-BDA also functionalizes O-SWNTs covalently because it reacts with epoxide groups on the nanotubes, as well as the cyanate ester (CE) matrix used. The resulting solution-cast CE composites show 57%, 71%, and 124% increases in Young's modulus, tensile strength, and toughness over neat CE. These values are higher than those of composites reinforced with pristine SWNTs, epoxidized SWNTs, and pristine SWNTs dispersed with PI(OH)-BDA. The modulus and strength increase per unit nanotube weight fraction, i.e., dE/dW(NT) and dσ/dW(NT), are 175 GPa and 7220 MPa, respectively, which are significantly higher than those of other nanotube/thermosetting composites (22-70 GPa and 140-3540 MPa, respectively). Our study indicates that covalent cum noncovalent functionalization of nanotubes is an effective tool for improving both the nanotube dispersion and nanotube/matrix interfacial interaction, resulting in significantly improved mechanical reinforcement of the solution-cast composites. PMID:22432973

  16. Covalent cum noncovalent functionalizations of carbon nanotubes for effective reinforcement of a solution cast composite film.

    PubMed

    Yuan, Wei; Chan-Park, Mary B

    2012-04-01

    Although carbon nanotubes have impressive tensile properties, exploiting these properties in composites, especially those made by the common solution casting technique, seems to be elusive thus far. The reasons could be partly due to the poor nanotube dispersion and the weak nanotube/matrix interface. To solve this dual pronged problem, we combine noncovalent and covalent functionalizations of nanotubes in a single system by the design and application of a novel dispersant, hydroxyl polyimide-graft-bisphenol A diglyceryl acrylate (PI(OH)-BDA), and use them with epoxidized single-walled carbon nanotubes (O-SWNTs). Our novel PI(OH)-BDA dispersant functionalizes the nanotubes noncovalently to achieve good dispersion of the nanotubes because of the strong π-π interaction due to main chain and steric hindrance of the BDA side chain. PI(OH)-BDA also functionalizes O-SWNTs covalently because it reacts with epoxide groups on the nanotubes, as well as the cyanate ester (CE) matrix used. The resulting solution-cast CE composites show 57%, 71%, and 124% increases in Young's modulus, tensile strength, and toughness over neat CE. These values are higher than those of composites reinforced with pristine SWNTs, epoxidized SWNTs, and pristine SWNTs dispersed with PI(OH)-BDA. The modulus and strength increase per unit nanotube weight fraction, i.e., dE/dW(NT) and dσ/dW(NT), are 175 GPa and 7220 MPa, respectively, which are significantly higher than those of other nanotube/thermosetting composites (22-70 GPa and 140-3540 MPa, respectively). Our study indicates that covalent cum noncovalent functionalization of nanotubes is an effective tool for improving both the nanotube dispersion and nanotube/matrix interfacial interaction, resulting in significantly improved mechanical reinforcement of the solution-cast composites.

  17. Crustal solute fluxes and transient carbon dioxide drawdown in the Scottbreen Basin, Svalbard in 2002

    NASA Astrophysics Data System (ADS)

    Krawczyk, Wiesława Ewa; Bartoszewski, Stefan A.

    2008-12-01

    SummarySolute fluxes and transient carbon dioxide drawdown in a small glacierized basin investigated on Svalbard in 2002 are presented. It was a sample year within a period of significant climate warming in the Arctic. Discharge was recorded in the Scottbreen Basin (10.1 km 2), Bellsund Fjord, between July 8 and September 10, 2002. Specific runoff for this period was 0.784 m, 22% more than the mean for 1986-2001. The runoff for all of 2002 (i.e. the hydrologic year) was estimated by comparison with Bayelva, the only glacial river with longer records on Svalbard. The specific runoff for 2002 was ˜1.228 m, yielding crustal solute fluxes of 69.4 t km -2 yr -1 (25.8 m 3 km -2 yr -1). This rate is the highest chemical denudation rate reported from glacierized basins on Svalbard, and it may be underestimated because higher solute fluxes at the beginning of the melt season were not taken into account. Crustal fluxes in the fall may also have been higher because it is probable that crustal ion concentrations were increasing after recording stopped in September. The cation denudation rate was 1213 ∑ meq + m -2 yr -1 and the mean annual crustal ion concentration derived from it amounted to 981 μeq L -1. Transient CO 2 drawdown in 2002 was 5242 kg C km -2 yr -1. Most of the carbon dioxide was removed in the summer ablation waters, estimated CO 2 drawdown in the fall being only 13% of the total. Comparison with crustal solute fluxes (CSF) computed from specific conductivity in the 1980s and 1990s suggests that earlier fluxes may have been overestimated by around 19%. Comparing earlier data with the 2002 rates may confirm the influence of climate warming on increasing chemical denudation rates. It was also found that a globally derived equation relating specific conductivity to concentrations of dissolved limestone in water gave estimates of the crustal solute fluxes that were only 1.1% less than those obtained via comprehensive chemical analyses of waters and ion

  18. Hydrophilic solutes in modified carbon dioxide extraction-prediction of the extractability using molecular dynamic simulation.

    PubMed

    Günther, Martina; Maus, Martin; Wagner, Karl Gerhard; Schmidt, Peter Christian

    2005-06-01

    Super- and subcritical carbon dioxide (CO2) extractions of crude drugs were simulated by molecular modelling to predict the extractability of different hydrophilic plant constituents under various extraction conditions. The CO2 extraction fluids were simulated either with pure CO2 or with solvent modified CO2 at different pressures and temperatures. Molecular modelling resulted in three different solubility parameters: the total solubility parameter delta and the partial solubility parameters delta(d) for the van der Waals and delta(EL) for the polar forces. Thus, delta(EL) enabled the estimation of the polarity of the extraction fluids and the solute molecules. If the value of delta(EL) of the extraction fluid reached the value of the solute molecule in the crude drug, i.e. minimum extraction value, the compound was soluble at the distinct extraction conditions. For a further increase in yield of the hydrophilic solutes, the polarity of the extraction fluid had to be increased, too. That means delta(EL) of the fluid exceeded the minimum extraction value. All simulations were verified by CO2 extractions of the secondary roots of Harpagophytum procumbens (harpagoside, stachyose) and the seeds of Aesculus hippocastanum (aescin). CO2 extractions of the flowers of Matricaria recutita ((-)-alpha-bisabolol) were obtained from literature data. These four constituents with different properties, like molecular size and the allocation of polar functional groups were extracted, analysed, simulated and the extract content was correlated with the extraction fluid used, respectively. PMID:15911229

  19. Adsorption of tetracycline from aqueous solutions onto multi-walled carbon nanotubes with different oxygen contents

    PubMed Central

    Yu, Fei; Ma, Jie; Han, Sheng

    2014-01-01

    Oxidized multi-walled carbon nanotubes (MWCNTs) with different oxygen contents were investigated for the adsorption of tetracycline (TC) from aqueous solutions. As the surface oxygen content of the MWCNTs increased, the maximum adsorption capacity and adsorption coefficient of TC increased to the largest values and then decreased. The relation can be attributed to the interplay between the nanotubes' dispersibility and the water cluster formation upon TC adsorption. The overall adsorption kinetics of TC onto CNTs-3.2%O might be dependent on both intra-particle diffusion and boundary layer diffusion. The maximum adsorption capacity of TC on CNTs-3.2%O was achieved in the pH range of 3.3–8.0 due to formation of water clusters or H-bonds. Furthermore, the presence of Cu2+ could significantly enhanced TC adsorption at pH of 5.0. However, the solution ionic strength did not exhibit remarkable effect on TC adsorption. In addition, when pH is beyond the range (3.3–8.0), the electrostatic interactions caused the decrease of TC adsorption capacity. Our results indicate that surface properties and aqueous solution chemistry play important roles in TC adsorption on MWCNTs. PMID:24937315

  20. Sorption of uranium from carbonate solutions by thin-layer sorbents based on titanium hydroxoperoxide and activated carbon, and the elution of uranium

    SciTech Connect

    Prishchepo, R.S.; Betenekov, N.D.; Pershko, A.A.; Vasilevskii, V.A.

    1986-05-01

    This paper studies the sorption of uranium from carbonate solutions and the elution of uranium under static conditions, on thin-layer inorganic sorbents obtained by homogeneous precipitation of titanium hydroperoxide on SKT activated carbon. The exchange capacity of the sorbents for uranium has been determined in relation to the quantity of titanium in the film, the sorbent particle size, and the contact time. Conditions have been selected for the elution.

  1. Solution spinning of a high-? oxide superconductor: the effect of poly(vinyl alcohol) spinning medium on the critical current density of melt-processed ? superconducting filaments

    NASA Astrophysics Data System (ADS)

    Tomita, Hisayo; Sunohara, Makoto; Goto, Tomoko; Takahashi, Kiyohisa

    1996-12-01

    The precursor 0953-2048/9/12/014/img9 filament was prepared by solution spinning through a homogeneous aqueous poly(vinyl alcohol) (PVA) solution of Y, Ba and Cu acetates. The solution spinning was successfully performed using PVA with degrees of polymerization (DP) of 1700 and 2450 and a degree of saponification of 85 mol%. The as-drawn filament was heated to remove volatile components and partially melted to generate a superconducting phase. The effects of the DP of PVA and a content of mixed acetates in the precursor filament on the critical current density 0953-2048/9/12/014/img10 of the melt-processed filament were examined. The higher 0953-2048/9/12/014/img11 was obtained for the filament spun from PVA solution of higher DP and lower acetate content. The highest 0953-2048/9/12/014/img11 value of 0953-2048/9/12/014/img13 at 77 K and 0 T was achieved for the filament spun from the DP 2450 PVA with an acetate to PVA ratio of two.

  2. Radiation-crosslinking of shape memory polymers based on poly(vinyl alcohol) in the presence of carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Basfar, A. A.; Lotfy, S.

    2015-01-01

    Shape memory polymers based on poly(vinyl alcohol) (SM-PVA) in the presence of 2-carboxyethyl acrylate oligomers (CEA) and multi-wall carbon nanotubes (MWCNTs) crosslinked by ionizing radiation were investigated. Chemical-crosslinking of PVA by glutaraldehyde in the presence of CEA and MWCNTs was also studied. The swelling and gel fraction of the radiation-crosslinked SM-PVA and chemically crosslinked systems were evaluated. Analysis of the swelling and gel fraction revealed a significant reduction in swelling and an increase in the gel fraction of the material that was chemically crosslinked with glutaraldehyde. The radiation-crosslinked SM-PVA demonstrated 100% gelation at an irradiation dose of 50 kGy. In addition, radiation-crosslinked SM-PVA exhibited good temperature responsive shape-memory behavior. A scanning electron microscopy (SEM) analysis was performed. The thermal properties of radiation-crosslinked SM-PVA were investigated by a thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA). The ability of the material to return or store energy (E‧), to its ability to lose energy (E″), and the ratio of these effects (Tanδ), which is called damping were examined via DMA. The temperature of Tanδ in the radiation-crosslinked SM-PVA decreased significantly by 6 and 13 °C as a result of the addition of MWCNTs. In addition, the temperature of Tanδ for SM-PVA increased as the irradiation dose increased. These radiation-crosslinked SM-PVA materials show promising shape-memory behavior based on the range of temperatures at which Tanδ appears.

  3. Removal of dyes from aqueous solutions using activated carbon prepared from rice husk residue.

    PubMed

    Li, Yaxin; Zhang, Xian; Yang, Ruiguang; Li, Guiying; Hu, Changwei

    2016-01-01

    The treatment of dye wastewater by activated carbon (AC) prepared from rice husk residue wastes was studied. Batch adsorption studies were conducted to investigate the effects of contact time, initial concentration (50-450 mg/L), pH (3-11) and temperature (30-70 °C) on the removal of methylene blue (MB), neutral red, and methyl orange. Kinetic investigation revealed that the adsorption of dyes followed pseudo-second-order kinetics. The results suggested that AC was effective to remove dyes, especially MB, from aqueous solutions. Desorption studies found that chemisorption by the adsorbent might be the major mode of dye removal. Fourier transform infrared results suggested that dye molecules were likely to combine with the O-H and P=OOH groups of AC. PMID:26942535

  4. Electrosorption of ions from aqueous solutions with carbon nanotubes and nanofibers composite film electrodes

    NASA Astrophysics Data System (ADS)

    Wang, X. Z.; Li, M. G.; Chen, Y. W.; Cheng, R. M.; Huang, S. M.; Pan, L. K.; Sun, Z.

    2006-07-01

    Electrosorption of ions from aqueous solutions with carbon nanotubes and nanofibers (CNTs-CNFs) composite film electrodes has been demonstrated. The large area CNTs-CNFs film was directly grown on Ni plate by low pressure and low temperature thermal chemical vapor deposition. The CNTs-CNFs electrodes have great advantages such as low cost, easy operation, long-term reproducibility, and integrity of monolithic CNTs-CNFs film and current collector. Batch-mode experiments at low voltage (0.4-2V) were conducted in a continuously recycling system to investigate the electrosorption process. Purification of water with good reproducibility was achieved because of optimal pore size distribution of CNTs-CNFs composite films.

  5. A solution processed top emission OLED with transparent carbon nanotube electrodes

    NASA Astrophysics Data System (ADS)

    Chien, Yu-Mo; Lefevre, Florent; Shih, Ishiang; Izquierdo, Ricardo

    2010-04-01

    Top emission organic light emitting diodes (OLEDs) with carbon nanotubes (CNTs) as top electrodes were fabricated and characterized. Devices were fabricated on glass substrates with evaporated bottom Al/LiF cathodes, a spin coated organic emissive layer and a PEDOT-PSS hole injection layer. Transparent thin CNT films were deposited on top of the emission layer to form the anode by micro-contact printing with a polydimethylsiloxane stamp. A very good device performance was obtained, with a peak luminance of 3588 cd m - 2 and a maximum current efficiency of 1.24 cd A - 1. This work shows the possibility of using CNTs as transparent electrodes to replace ITO in organic semiconductor devices. Furthermore, the top emission nature of such devices offers a broader range of applications of CNTs on any type of substrate. By combining with solution processed organic materials, it is anticipated that lower cost fabrication will be possible through roll-to-roll manufacture.

  6. Kinetic adsorption of application of carbon nanotubes for Pb(II) removal from aqueous solution.

    PubMed

    Kabbashi, Nassereldeen A; Atieh, Muataz A; Al-Mamun, Abdullah; Mirghami, Mohamed E S; Alam, M D Z; Yahya, Noorahayu

    2009-01-01

    The capability of carbon nanotubes (CNTs) to adsorb lead (Pb) in aqueous solution was investigated. Batch mode adsorption experiment was conducted to determine the effects of pH, agitation speed, CNTs dosage and contact time. The removal of Pb(II) reached maximum value 85% or 83% at pH 5 or 40 mg/L of CNTs, respectively. Higher correlation coefficients from Langmuir isotherm model indicates the strong adsorptions of Pb(II) on the surface of CNTs (adsorption capacity Xm = 102.04 mg/g). The results indicates that the highest percentage removal of Pb (96.03%) can be achieved at pH 5, 40 mg/L of CNTs, contact time 80 min, and agitation speed 50 r/min.

  7. In situ extended X-ray absorption fine structure study during selective alcohol oxidation over Pd/Al2O3 in supercritical carbon dioxide.

    PubMed

    Grunwaldt, Jan-Dierk; Caravati, Matteo; Baiker, Alfons

    2006-05-25

    High-pressure in situ X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) data are reported during the selective oxidation of benzyl alcohol to benzaldehyde in supercritical carbon dioxide over a Pd/Al(2)O(3) catalyst (shell impregnated). For this purpose, a continuous-flow system with a spectroscopic cell suitable for in situ X-ray absorption studies on heterogeneous catalysts up to 200 degrees C and 200 bar has been developed. Due to the high contribution of the dense fluid to the overall X-ray absorption, high stability of the process pressure is mandatory, particularly when recording EXAFS spectra. According to EXAFS and XANES results, the palladium particles were fully reduced after exposure to benzyl alcohol in scCO(2). In contrast to Pd-catalyzed liquid-phase oxidation, a higher oxygen tolerance of the catalyst was observed. Palladium was partially oxidized on the surface under typical reaction conditions (0.9 mol % benzyl alcohol/0.5 mol % O(2) in carbon dioxide), which gradually increased when the concentration of oxygen in the feed was raised. Both XANES and EXAFS data uncovered that palladium is mainly oxidized on the surface or within the outermost layers. These results are in accordance with simulations of the XANES data using the FEFF8.20 code (program for ab initio calculations on multiple scattering XAS) and EXAFS data fitting/simulation. PMID:16706447

  8. Electrochemical activation of carbon cloth in aqueous inorganic salt solution for superior capacitive performance

    NASA Astrophysics Data System (ADS)

    Ye, Dong; Yu, Yao; Tang, Jie; Liu, Lin; Wu, Yue

    2016-05-01

    Carbon cloth (CC) is an inexpensive and highly conductive textile with excellent mechanical flexibility and strength; it holds great promise as an electrode material for flexible supercapacitors. However, pristine CC has such a low surface area and poor electrochemical activity that the energy storage capability is usually very poor. Herein, we report a green method, two-step electrochemical activation in an aqueous solution of inorganic salts, to significantly enhance the capacitance of CC for supercapacitor application. Micro-cracks, exfoliated carbon fiber shells, and oxygen-containing functional groups (OFGs) were introduced onto the surface of the carbon filament. This resulted in an enhancement of over two orders of magnitude in capacitance compared to that of the bare CC electrode, reaching up to a maximum areal capacitance of 505.5 mF cm-2 at the current density of 6 mA cm-2 in aqueous H2SO4 electrolyte. Electrochemical reduction of CC electrodes led to the removal of most electrochemically unstable surface OFGs, resulting in superior charging/discharging rate capability and excellent cycling stability. Although the activated CC electrode contained a high-level of surface oxygen functional groups (~15 at%), it still exhibited a remarkable charging-discharging rate capability, retaining ~88% of the capacitance when the charging rate increased from 6 to 48 mA cm-2. Moreover, the activated CC electrode exhibited excellent cycling stability with ~97% capacitance remaining after 10 000 cycles at a current density of 24 mA cm-2. A symmetrical supercapacitor based on the activated CC exhibited an ideal capacitive behavior and fast charge-discharge properties. Such a simple, environment-friendly, and cost-effective strategy to activate CC shows great potential in the fabrication of high-performance flexible supercapacitors.Carbon cloth (CC) is an inexpensive and highly conductive textile with excellent mechanical flexibility and strength; it holds great promise as

  9. Carbon nanotubes dispersed in aqueous solution by ruthenium(ii) polypyridyl complexes

    NASA Astrophysics Data System (ADS)

    Huang, Kewei; Saha, Avishek; Dirian, Konstantin; Jiang, Chengmin; Chu, Pin-Lei E.; Tour, James M.; Guldi, Dirk M.; Martí, Angel A.

    2016-07-01

    Cationic ruthenium(ii) polypyridyl complexes with appended pyrene groups have been synthesized and used to disperse single-walled carbon nanotubes (SWCNT) in aqueous solutions. To this end, planar pyrene groups enable association by means of π-stacking onto carbon nanotubes and, in turn, the attachment of the cationic ruthenium complexes. Importantly, the ionic nature of the ruthenium complexes allows the formation of stable dispersions featuring individualized SWCNTs in water as confirmed in a number of spectroscopic and microscopic assays. In addition, steady-state photoluminescence spectroscopy was used to probe the excited state interactions between the ruthenium complexes and SWCNTs. These studies show that the photoluminescence of both, that is, of the ruthenium complexes and of SWCNTs, are quenched when they interact with each other. Pump-probe transient absorption experiments were performed to shed light onto the nature of the photoluminescence quenching, showing carbon nanotube-based bands with picosecond lifetimes, but no new bands which could be unambigously assigned to photoinduced charge transfer process. Thus, from the spectroscopic data, we conclude that quenching of the photoluminescence of the ruthenium complexes is due to energy transfer to proximal SWCNTs.Cationic ruthenium(ii) polypyridyl complexes with appended pyrene groups have been synthesized and used to disperse single-walled carbon nanotubes (SWCNT) in aqueous solutions. To this end, planar pyrene groups enable association by means of π-stacking onto carbon nanotubes and, in turn, the attachment of the cationic ruthenium complexes. Importantly, the ionic nature of the ruthenium complexes allows the formation of stable dispersions featuring individualized SWCNTs in water as confirmed in a number of spectroscopic and microscopic assays. In addition, steady-state photoluminescence spectroscopy was used to probe the excited state interactions between the ruthenium complexes and SWCNTs

  10. [What control solutions should be used in studies on the acute effect of alcohol on the gastrointestinal tract?].

    PubMed

    Singer, M V

    1983-10-01

    There exists still a considerable confusion in the literature about the appropriate control solution for ethanol. In many studies either no control or equimolar solutions of urea, mannitol or sodium chloride were used as an osmotic control for ethanol; distilled water being given only in a few cases. The confusion is mainly derived from the opinion that the osmolality of the ethanol solution as measured by freezing point depression (= "theoretical osmotic pressure") is the determinant factor for the action of ethanol on the gastrointestinal tract. This opinion, however, is not correct. Since biological membranes are not perfectly semipermeable (i. e., they are permeable to certain solutes) the "effective osmotic pressure" produced by permeant solutes is always less than the ("theoretical") osmotic pressure as determined by freezing point depression. The ratio of the "effective" to the "theoretical" osmotic pressure of a solute is defined by the Stavermann reflection coefficient for a certain membrane. The Stavermann reflection coefficient may have any value between 1 and 0. For an impermeant solute the reflection coefficient equals 1 and for increasingly permeant solutes it becomes progressively less than 1 and closer to 0. The Stavermann reflection coefficient of ethanol for some gastrointestinal organs tested is about 0.1. The ideal osmotic control for ethanol would be a solute which exerts the same effective osmotic pressure on the gastrointestinal membrane as ethanol, i. e. which has the same Stavermann reflection coefficient as ethanol, and has no specific pharmacologic effect. Distilled water seems to be the most suitable osmotic control for ethanol because it has a Stavermann reflection coefficient of 0 and has no pharmacological actions.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:6649735

  11. [What control solutions should be used in studies on the acute effect of alcohol on the gastrointestinal tract?].

    PubMed

    Singer, M V

    1983-10-01

    There exists still a considerable confusion in the literature about the appropriate control solution for ethanol. In many studies either no control or equimolar solutions of urea, mannitol or sodium chloride were used as an osmotic control for ethanol; distilled water being given only in a few cases. The confusion is mainly derived from the opinion that the osmolality of the ethanol solution as measured by freezing point depression (= "theoretical osmotic pressure") is the determinant factor for the action of ethanol on the gastrointestinal tract. This opinion, however, is not correct. Since biological membranes are not perfectly semipermeable (i. e., they are permeable to certain solutes) the "effective osmotic pressure" produced by permeant solutes is always less than the ("theoretical") osmotic pressure as determined by freezing point depression. The ratio of the "effective" to the "theoretical" osmotic pressure of a solute is defined by the Stavermann reflection coefficient for a certain membrane. The Stavermann reflection coefficient may have any value between 1 and 0. For an impermeant solute the reflection coefficient equals 1 and for increasingly permeant solutes it becomes progressively less than 1 and closer to 0. The Stavermann reflection coefficient of ethanol for some gastrointestinal organs tested is about 0.1. The ideal osmotic control for ethanol would be a solute which exerts the same effective osmotic pressure on the gastrointestinal membrane as ethanol, i. e. which has the same Stavermann reflection coefficient as ethanol, and has no specific pharmacologic effect. Distilled water seems to be the most suitable osmotic control for ethanol because it has a Stavermann reflection coefficient of 0 and has no pharmacological actions.(ABSTRACT TRUNCATED AT 250 WORDS)

  12. Electrodeposition of tantalum on carbon black in non-aqueous solution and its electrocatalytic properties.

    PubMed

    Jo, Ara; Lee, Youngmi; Lee, Chongmok

    2016-08-24

    In this work, we synthesized tantalum (Ta) nanoclusters on carbon black (Ta/CB) via simple electrodeposition in non-aqueous solvent, acetonitrile (ACN) at ambient temperature. Transmission electron microscopy (TEM) images showed that the electrodeposited Ta nanoclusters consisted of tiny Ta nanoparticles. X-ray photoelectron spectroscopy (XPS) result represented that the outermost Ta formed the native oxide on Ta/CB due to its ambient exposure to air. Electrochemical catalytic properties of prepared Ta/CB on glassy carbon electrode (Ta/CB/GC) were investigated toward reductions of oxygen and hydrogen peroxide, and oxidations of ascorbic acid and dopamine. For oxygen reduction reaction (ORR) in acid, Ta/CB/GC represented a decent electrocatalytic performance which was better or comparable to bare Pt. The operational stability in acidic condition was maintained up to 500 repetitive potential cycles presumably due to the protective native Ta oxide layer. Ta/CB/GC also showed high amperometric sensitivity (4.5 (±0.16) mA mM(-1) cm(-2), n = 5) for reduction of hydrogen peroxide in 0.1 M phosphate buffer solution (PBS, pH 7.4). In addition, Ta/CB/GC was demonstrated for the possibility of simultaneous detection of ascorbic acid and dopamine using differential pulse voltammetry (DPV).

  13. Hybrid multiwalled carbon nanotube--Laponite sorbent for removal of methylene blue from aqueous solutions.

    PubMed

    Loginov, Maksym; Lebovka, Nikolai; Vorobiev, Eugene

    2014-10-01

    The article discusses adsorption of methylene blue dye by novel hybrid sorbent consisting of Laponite and multiwalled carbon nanotubes. The sorbent was obtained by sonication of the aqueous suspensions of nanotubes at different concentrations of Laponite. The methods of the methylene blue adsorption, dead-end membrane filtration and environmental scanning electron microscopy were used for the sorbent characterization. It may be concluded from the results of filtration and adsorption experiments that sonication of mixed aqueous suspensions of Laponite and multiwalled carbon nanotubes leads to the formation of hybrid particles (ML-particles) with a core-shell structure. The size and the shape of hybrid particles were determined by nanotubes, while their adsorption properties were determined by Laponite particles attached to the surface of nanotubes. The Laponite content in hybrid particles was corresponding to the Laponite to nanotubes ratio in the initial suspension X(L)=0-1. Due to the presence of Laponite in the sorbent, its adsorbing capacity was much higher as compared to the adsorbing capacity of pure nanotubes, and it was directly proportional to the Laponite content. This sorbent may be used either as a purifying additive or as a filtering layer if it is deposited on the surface of a supporting membrane. Due to relatively large size of hybrid particles, they can be easily separated from the purified solution by filtration or centrifugation.

  14. Salt Solutions in Carbon Nanotubes: The Role of Cation- π Interactions

    NASA Astrophysics Data System (ADS)

    Pham, Tuan Anh; Mortuza, Golam; Wood, Brandon; Lau, Edmond; Ogitsu, Tadashi; Buchsbaum, Steven; Siwy, Zuzanna; Fornasiero, Francesco; Schwegler, Eric

    Understanding the structure of aqueous electrolytes at interfaces is essential for predicting and optimizing device performances for a wide variety of emerging energy and environmental technologies. In this work, we investigate the structure of two common salt solutions, NaCl and KCl, at a hydrophobic interface within narrow carbon nanotubes (CNTs). Using a combination of first-principles and classical molecular dynamics simulations, we find that the solvation structure of the cations in the CNTs can deviate substantially from the conventional weakly interacting hydrophobic picture. Instead, interactions between solvated ions and the π-orbitals of the CNTs are found to play a critically important role, with the ion solvation structure ultimately determined by a subtle interplay between cation- π interactions and the intrinsic flexibility of the solvation shell. In the case of K+, these effects result in an unusually strong propensity to partially desolvate and reside closer to the carbon wall than either Na+ and Cl-, in sharp contrast to the known ion ordering at the water-vapor interface. This work was performed under the auspices of the U.S. Department of Energy by LLNL under Contract DE-AC52-07NA27344.

  15. Mechanisms of enhanced total organic carbon elimination from oxalic acid solutions by electro-peroxone process.

    PubMed

    Wang, Huijiao; Yuan, Shi; Zhan, Juhong; Wang, Yujue; Yu, Gang; Deng, Shubo; Huang, Jun; Wang, Bin

    2015-09-01

    Electro-peroxone (E-peroxone) is a novel electrocatalytic ozonation process that combines ozonation and electrolysis process to enhance pollutant degradation during water and wastewater treatment. This enhancement has been mainly attributed to several mechanisms that increase O3 transformation to ·OH in the E-peroxone system, e.g., electro-generation of H2O2 from O2 at a carbon-based cathode and its subsequent peroxone reaction with O3 to ·OH, electro-reduction of O3 to ·OH at the cathode, and O3 decomposition to ·OH at high local pH near the cathode. To get more insight how these mechanisms contribute respectively to the enhancement, this study investigated total organic carbon (TOC) elimination from oxalic acid (OA) solutions by the E-peroxone process. Results show that the E-peroxone process significantly increased TOC elimination rate by 10.2-12.5 times compared with the linear addition of the individual rates of corresponding ozonation and electrolysis process. Kinetic analyses reveal that the electrochemically-driven peroxone reaction is the most important mechanism for the enhanced TOC elimination rate, while the other mechanisms contribute minor to the enhancement by a factor of 1.6-2.5. The results indicate that proper selection of electrodes that can effectively produce H2O2 at the cathode is critical to maximize TOC elimination in the E-peroxone process.

  16. Mechanisms of enhanced total organic carbon elimination from oxalic acid solutions by electro-peroxone process.

    PubMed

    Wang, Huijiao; Yuan, Shi; Zhan, Juhong; Wang, Yujue; Yu, Gang; Deng, Shubo; Huang, Jun; Wang, Bin

    2015-09-01

    Electro-peroxone (E-peroxone) is a novel electrocatalytic ozonation process that combines ozonation and electrolysis process to enhance pollutant degradation during water and wastewater treatment. This enhancement has been mainly attributed to several mechanisms that increase O3 transformation to ·OH in the E-peroxone system, e.g., electro-generation of H2O2 from O2 at a carbon-based cathode and its subsequent peroxone reaction with O3 to ·OH, electro-reduction of O3 to ·OH at the cathode, and O3 decomposition to ·OH at high local pH near the cathode. To get more insight how these mechanisms contribute respectively to the enhancement, this study investigated total organic carbon (TOC) elimination from oxalic acid (OA) solutions by the E-peroxone process. Results show that the E-peroxone process significantly increased TOC elimination rate by 10.2-12.5 times compared with the linear addition of the individual rates of corresponding ozonation and electrolysis process. Kinetic analyses reveal that the electrochemically-driven peroxone reaction is the most important mechanism for the enhanced TOC elimination rate, while the other mechanisms contribute minor to the enhancement by a factor of 1.6-2.5. The results indicate that proper selection of electrodes that can effectively produce H2O2 at the cathode is critical to maximize TOC elimination in the E-peroxone process. PMID:25989593

  17. Electrodeposition of tantalum on carbon black in non-aqueous solution and its electrocatalytic properties.

    PubMed

    Jo, Ara; Lee, Youngmi; Lee, Chongmok

    2016-08-24

    In this work, we synthesized tantalum (Ta) nanoclusters on carbon black (Ta/CB) via simple electrodeposition in non-aqueous solvent, acetonitrile (ACN) at ambient temperature. Transmission electron microscopy (TEM) images showed that the electrodeposited Ta nanoclusters consisted of tiny Ta nanoparticles. X-ray photoelectron spectroscopy (XPS) result represented that the outermost Ta formed the native oxide on Ta/CB due to its ambient exposure to air. Electrochemical catalytic properties of prepared Ta/CB on glassy carbon electrode (Ta/CB/GC) were investigated toward reductions of oxygen and hydrogen peroxide, and oxidations of ascorbic acid and dopamine. For oxygen reduction reaction (ORR) in acid, Ta/CB/GC represented a decent electrocatalytic performance which was better or comparable to bare Pt. The operational stability in acidic condition was maintained up to 500 repetitive potential cycles presumably due to the protective native Ta oxide layer. Ta/CB/GC also showed high amperometric sensitivity (4.5 (±0.16) mA mM(-1) cm(-2), n = 5) for reduction of hydrogen peroxide in 0.1 M phosphate buffer solution (PBS, pH 7.4). In addition, Ta/CB/GC was demonstrated for the possibility of simultaneous detection of ascorbic acid and dopamine using differential pulse voltammetry (DPV). PMID:27496997

  18. Titanium Implant Osseointegration Problems with Alternate Solutions Using Epoxy/Carbon-Fiber-Reinforced Composite

    PubMed Central

    Petersen, Richard C.

    2014-01-01

    The aim of the article is to present recent developments in material research with bisphenyl-polymer/carbon-fiber-reinforced composite that have produced highly influential results toward improving upon current titanium bone implant clinical osseointegration success. Titanium is now the standard intra-oral tooth root/bone implant material with biocompatible interface relationships that confer potential osseointegration. Titanium produces a TiO2 oxide surface layer reactively that can provide chemical bonding through various electron interactions as a possible explanation for biocompatibility. Nevertheless, titanium alloy implants produce corrosion particles and fail by mechanisms generally related to surface interaction on bone to promote an inflammation with fibrous aseptic loosening or infection that can require implant removal. Further, lowered oxygen concentrations from poor vasculature at a foreign metal surface interface promote a build-up of host-cell-related electrons as free radicals and proton acid that can encourage infection and inflammation to greatly influence implant failure. To provide improved osseointegration many different coating processes and alternate polymer matrix composite (PMC) solutions have been considered that supply new designing potential to possibly overcome problems with titanium bone implants. Now for important consideration, PMCs have decisive biofunctional fabrication possibilities while maintaining mechanical properties from addition of high-strengthening varied fiber-reinforcement and complex fillers/additives to include hydroxyapatite or antimicrobial incorporation through thermoset polymers that cure at low temperatures. Topics/issues reviewed in this manuscript include titanium corrosion, implant infection, coatings and the new epoxy/carbon-fiber implant results discussing osseointegration with biocompatibility related to nonpolar molecular attractions with secondary bonding, carbon fiber in vivo properties, electrical

  19. Kinetics of catalytic oxidation of sulfide in aqueous solutions on activated carbon and slime of green lye

    SciTech Connect

    Yakovlev, V.A.; Andreev, S.B.

    1993-12-20

    The kinetics of heterogeneous catalytic oxidation of sulfide ion in alkali solutions by dissolved oxygen with activated carbon and the carbon component of the slime of green lye (the waste of paper and pulp production) as the catalysts has been studied experimentally. The apparent and actual rate constants of the oxidation are measured within the framework of the model of the first order reaction under diffusive limitations.

  20. Alcohol Alert

    MedlinePlus

    ... Us You are here Home » Alcohol Alert Alcohol Alert The NIAAA Alcohol Alert is a quarterly bulletin that disseminates important research ... text. To order single copies of select Alcohol Alerts, see ordering Information . To view publications in PDF ...

  1. Alcoholism - resources

    MedlinePlus

    Resources - alcoholism ... The following organizations are good resources for information on alcoholism : Alcoholics Anonymous -- www.aa.org Al-Anon/Alateen -- www.al-anon.org/home National Institute on Alcohol ...

  2. Alcoholic neuropathy

    MedlinePlus

    Neuropathy - alcoholic; Alcoholic polyneuropathy ... The exact cause of alcoholic neuropathy is unknown. It likely includes both a direct poisoning of the nerve by the alcohol and the effect of poor nutrition ...

  3. Alcohol Facts

    MedlinePlus

    ... raquo Alcohol Facts Alcohol Facts Listen Drinks like beer, malt liquor, wine, and hard liquor contain alcohol. Alcohol is the ingredient that gets you drunk. Hard liquor—such as whiskey, rum, or gin—has more ...

  4. User-oriented batch reactor solutions to the homogeneous surface diffusion model for different activated carbon dosages.

    PubMed

    Zhang, Qiong; Crittenden, John; Hristovski, Kiril; Hand, David; Westerhoff, Paul

    2009-04-01

    This paper presents a simplified approach and user-oriented solutions to the homogeneous surface diffusion model (HSDM) equations for determining the surface diffusivity using a batch reactor system. Once the surface diffusivity is known, this model could also be used to estimate the performance of activated carbon (AC) applications as a function of contact time. In addition, fixed-bed performance can be predicted using the user-oriented solutions to the HSDM for fixed beds. The step-by-step procedure for determining surface diffusion coefficients of an activated carbon adsorber, which was initially developed by Hand, Crittenden and Thacker in 1983 for a carbon dose where C(equilibrium)/C(0)=0.5, is modified to allow calculations for different carbon dosages. This modification provides solutions to the HSDM equations for different activated carbon dosages. The solutions to the HSDM framework are provided as simplified algebraic equations suitable for quick and easy estimations of D(S). The excel spread sheet is provided in the supplemental information and a detailed example is discussed. PMID:19249812

  5. Adsorption kinetics of a basic dye from aqueous solutions onto apricot stone activated carbon.

    PubMed

    Demirbas, E; Kobya, M; Sulak, M T

    2008-09-01

    The preparation of activated carbon from apricot stone with H(2)SO(4) activation and its ability to remove a basic dye, astrazon yellow 7 GL, from aqueous solutions were reported in this study. The adsorbent was characterized by FTIR, BET and SEM, respectively. The effects of various experimental parameters, such as initial dye concentration, pH, adsorbent dosage and temperature were investigated in a batch-adsorption technique. The optimum conditions for removal of the basic dye were found to be pH 10, 6g/l of adsorbent dosage and equilibrium time of 35 min, respectively. A comparison of three kinetic models, the pseudo first-order, second-order and diffusion controlled kinetic models, on the basic dye-adsorbent system showed that the removal rate was heavily dependent on diffusion controlled kinetic models. The adsorption isotherm data were fitted well to Langmuir and Freundlich isotherms. The adsorption capacity was calculated as 221.23 mg/g at 50 degrees C. Thermodynamics parameters were also evaluated. The values of enthalpy and entropy were 49.87 kJ/mol and 31.93 J/mol K, respectively, indicating that this process was spontaneous and endothermic. The experimental studies were indicated that ASC had the potential to act as an alternative adsorbent to remove the basic dye from aqueous solutions. PMID:18093829

  6. Solution-processed carbon nanotube thin-film complementary static random access memory

    NASA Astrophysics Data System (ADS)

    Geier, Michael L.; McMorrow, Julian J.; Xu, Weichao; Zhu, Jian; Kim, Chris H.; Marks, Tobin J.; Hersam, Mark C.

    2015-11-01

    Over the past two decades, extensive research on single-walled carbon nanotubes (SWCNTs) has elucidated their many extraordinary properties, making them one of the most promising candidates for solution-processable, high-performance integrated circuits. In particular, advances in the enrichment of high-purity semiconducting SWCNTs have enabled recent circuit demonstrations including synchronous digital logic, flexible electronics and high-frequency applications. However, due to the stringent requirements of the transistors used in complementary metal-oxide-semiconductor (CMOS) logic as well as the absence of sufficiently stable and spatially homogeneous SWCNT thin-film transistors, the development of large-scale SWCNT CMOS integrated circuits has been limited in both complexity and functionality. Here, we demonstrate the stable and uniform electronic performance of complementary p-type and n-type SWCNT thin-film transistors by controlling adsorbed atmospheric dopants and incorporating robust encapsulation layers. Based on these complementary SWCNT thin-film transistors, we simulate, design and fabricate arrays of low-power static random access memory circuits, achieving large-scale integration for the first time based on solution-processed semiconductors.

  7. Solution-processed zinc oxide nanoparticles/single-walled carbon nanotubes hybrid thin-film transistors

    NASA Astrophysics Data System (ADS)

    Liu, Fangmei; Sun, Jia; Qian, Chuan; Hu, Xiaotao; Wu, Han; Huang, Yulan; Yang, Junliang

    2016-09-01

    Solution-processed thin-film transistors (TFTs) are the essential building blocks for manufacturing the low-cost and large-area consumptive electronics. Herein, solution-processed TFTs based on the composites of zinc oxide (ZnO) nanoparticles and single-walled carbon nanotubes (SWCNTs) were fabricated by the methods of spin-coating and doctor-blading. Through controlling the weight of SWCNTs, the ZnO/SWCNTs TFTs fabricated by spin-coating demonstrated a field-effect mobility of 4.7 cm2/Vs and a low threshold voltage of 0.8 V, while the TFTs devices fabricated by doctor-blading technique showed reasonable electrical performance with a mobility of 0.22 cm2/Vs. Furthermore, the ion-gel was used as an efficient electrochemical gate dielectric because of its large electric double-layer capacitance. The operating voltage of all the TFTs devices is as low as 4.0 V. The research suggests that ZnO/SWCNTs TFTs have the potential applications in low-cost, large-area and flexible consumptive electronics, such as chemical-biological sensors and smart label.

  8. Removal of methylene blue from aqueous solution by wood millet carbon optimization using response surface methodology.

    PubMed

    Ghaedi, Mehrorang; Nasiri Kokhdan, Syamak

    2015-02-01

    The use of cheep, non-toxic, safe and easily available adsorbent are efficient and recommended material and alternative to the current expensive substance for pollutant removal from wastewater. The activated carbon prepared from wood waste of local tree (millet) extensively was applied for quantitative removal of methylene blue (MB), while simply. It was used to re-used after heating and washing with alkaline solution of ethanol. This new adsorbent was characterized by using BET surface area measurement, FT-IR, pH determination at zero point of charge (pHZPC) and Boehm titration method. Response surface methodology (RSM) by at least the number of experiments main and interaction of experimental conditions such as pH of solution, contact time, initial dye concentration and adsorbent dosage was optimized and set as pH 7, contact time 18 min, initial dye concentration 20 ppm and 0.2 g of adsorbent. It was found that variable such as pH and amount of adsorbent as solely or combination effects seriously affect the removal percentage. The fitting experimental data with conventional models reveal the applicability of isotherm models Langmuir model for their well presentation and description and Kinetic real rate of adsorption at most conditions efficiently can be represented pseudo-second order, and intra-particle diffusion. It novel material is good candidate for removal of huge amount of MB (20 ppm) in short time (18 min) by consumption of small amount (0.2 g).

  9. Nature of Glycine and Its α-Carbon Radical in Aqueous Solution: A Theoretical Investigation.

    PubMed

    Wood, Geoffrey P F; Gordon, Mark S; Radom, Leo; Smith, David M

    2008-10-14

    Quantum chemistry calculations and classical molecular dynamics simulations have been used to examine the equilibria in solution between the neutral and zwitterionic forms of glycine and also of the glycyl radical. The established preference (by 30 kJ mol(-1)) for the zwitterion of glycine was confirmed by both the quantum chemical calculations and the classical molecular dynamics simulations. The best agreement with experiment was derived from thermodynamic integration calculations of explicitly solvated systems, which gives a free energy difference of 36.6 ± 0.6 kJ mol(-1). In contrast, for the glycyl radical in solution, the neutral form is preferred, with a calculated free energy difference of 54.8 ± 0.6 kJ mol(-1). A detailed analysis of the microsolvation environments of each species was carried out by evaluating radial distribution functions and hydrogen bonding patterns. This analysis provides evidence that the change in preference between glycine and glycyl radical is due to the inherent gas-phase stability of the neutral α-carbon radical rather than to any significant difference in the solvation behavior of the constituent species. PMID:26620181

  10. Removal of methylene blue from aqueous solution by wood millet carbon optimization using response surface methodology

    NASA Astrophysics Data System (ADS)

    Ghaedi, Mehrorang; Kokhdan, Syamak Nasiri

    2015-02-01

    The use of cheep, non-toxic, safe and easily available adsorbent are efficient and recommended material and alternative to the current expensive substance for pollutant removal from wastewater. The activated carbon prepared from wood waste of local tree (millet) extensively was applied for quantitative removal of methylene blue (MB), while simply. It was used to re-used after heating and washing with alkaline solution of ethanol. This new adsorbent was characterized by using BET surface area measurement, FT-IR, pH determination at zero point of charge (pHZPC) and Boehm titration method. Response surface methodology (RSM) by at least the number of experiments main and interaction of experimental conditions such as pH of solution, contact time, initial dye concentration and adsorbent dosage was optimized and set as pH 7, contact time 18 min, initial dye concentration 20 ppm and 0.2 g of adsorbent. It was found that variable such as pH and amount of adsorbent as solely or combination effects seriously affect the removal percentage. The fitting experimental data with conventional models reveal the applicability of isotherm models Langmuir model for their well presentation and description and Kinetic real rate of adsorption at most conditions efficiently can be represented pseudo-second order, and intra-particle diffusion. It novel material is good candidate for removal of huge amount of MB (20 ppm) in short time (18 min) by consumption of small amount (0.2 g).

  11. Removal of 2,4-dichlorophenol from aqueous solution by static-air-activated carbon fibers.

    PubMed

    Wang, Jian-Ping; Chen, Yong-Zhen; Feng, Hui-Min; Zhang, Shu-Juan; Yu, Han-Qing

    2007-09-01

    Static-air-activated carbon fibers (ACFs) with lotus-root-like axially porous structure were used to adsorb 2,4-dichlorophenol (2,4-DCP) from aqueous solution. The adsorption isotherm was evaluated in the pH range 3.0-11.0. Results indicated that both Langmuir and Redlich-Peterson adsorption isotherms were appropriate for describing the adsorption characteristics of 2,4-DCP at various pH values and that lower pH values were favorable for adsorption. The adsorption of 2,4-DCP was controlled by the synergetic effects of pi-pi interaction and electrostatic attraction, and the former was dominant. Breakthrough curve results showed that the 2,4-DCP removal efficiency increased with an increase in the empty-bed contact time (EBCT). An EBCT of 0.660 min was sufficient for the adsorption of 2,4-DCP onto ACF, indicating a high adsorption rate. Desorption experiment results revealed that the ACF saturated with 2,4-DCP could be regenerated effectively by a 0.001 M NaOH solution. PMID:17509602

  12. Elution of zinc in dust discharged from electric arc furnace in carbonic acid solution

    NASA Astrophysics Data System (ADS)

    Yokoyama, S.; Sasaki, T.; Sasano, J.; Izaki, M.

    2012-03-01

    The dust discharged from an electric arc furnace (EAF) is a valuable resource of zinc. As a fundamental study of extraction of zinc, iron and chlorine in the EAF dust, the elution behavior of them in carbonic acid solution was studied. The influence of the weight of the EAF dust on the elution behavior was examined in this study. Experiment was carried out putting the EAF dust from 1 g to 200 g in weight into 1 L of water that was introduced by CO2. Generally, the pH in the aqueous solution increased with an increase in weight of the additive EAF dust. Maximums of the eluted concentrations of zinc and chloride ion increased with an increase in the weight of the additive EAF dust whereas the extraction ratios of both of them decreased with an increase in the weight of the additive EAF dust. Iron in the EAF dust remained in the dust without elution. The limit of extraction of zinc from the EAF dust to water was given by the solubilities of ZnFe2O4 and ZnO expressed by eq. (6) and eq. (9) respectively.

  13. Adsorption and desorption of dissolved organic matter by carbon nanotubes: Effects of solution chemistry.

    PubMed

    Engel, Maya; Chefetz, Benny

    2016-06-01

    Increasing use of carbon nanotubes (CNTs) has led to their introduction into the environment where they can interact with dissolved organic matter (DOM). This study focuses on solution chemistry effects on DOM adsorption/desorption processes by single-walled CNTs (SWCNTs). Our data show that DOM adsorption is controlled by the attachment of DOM molecules to the SWCNTs, and that the initial adsorption rate is dependent on solution parameters. Adsorbed amount of DOM at high ionic strength was limited, possibly due to alterations in SWCNT bundling. Desorption of DOM performed at low pH resulted in additional DOM adsorption, whereas at high pH, adsorbed DOM amount decreased. The extent of desorption conducted at increased ionic strength was dependent on pre-adsorbed DOM concentration: low DOM loading stimulated additional adsorption of DOM, whereas high DOM loading facilitated release of adsorbed DOM. Elevated ionic strength and increased adsorbed amount of DOM reduced the oxidation temperature of the SWCNTs, suggesting that changes in the assembly of the SWCNTs had occurred. Moreover, DOM-coated SWCNTs at increased ionic strength provided fewer sites for atrazine adsorption. This study enhances our understanding of DOM-SWCNT interactions in aqueous systems influenced by rapid changes in salinity, and facilitates potential use of SWCNTs in water-purification technologies.

  14. Solution-processed carbon nanotube thin-film complementary static random access memory.

    PubMed

    Geier, Michael L; McMorrow, Julian J; Xu, Weichao; Zhu, Jian; Kim, Chris H; Marks, Tobin J; Hersam, Mark C

    2015-11-01

    Over the past two decades, extensive research on single-walled carbon nanotubes (SWCNTs) has elucidated their many extraordinary properties, making them one of the most promising candidates for solution-processable, high-performance integrated circuits. In particular, advances in the enrichment of high-purity semiconducting SWCNTs have enabled recent circuit demonstrations including synchronous digital logic, flexible electronics and high-frequency applications. However, due to the stringent requirements of the transistors used in complementary metal-oxide-semiconductor (CMOS) logic as well as the absence of sufficiently stable and spatially homogeneous SWCNT thin-film transistors, the development of large-scale SWCNT CMOS integrated circuits has been limited in both complexity and functionality. Here, we demonstrate the stable and uniform electronic performance of complementary p-type and n-type SWCNT thin-film transistors by controlling adsorbed atmospheric dopants and incorporating robust encapsulation layers. Based on these complementary SWCNT thin-film transistors, we simulate, design and fabricate arrays of low-power static random access memory circuits, achieving large-scale integration for the first time based on solution-processed semiconductors. PMID:26344184

  15. Direct Assembly of Modified Proteins on Carbon Nanotubes in an Aqueous Solution

    NASA Technical Reports Server (NTRS)

    Kim, Jae-Woo; Lillehei, Peter T.; Park, Cheol; Harrison, Joycelyn S.

    2007-01-01

    Carbon nanotubes (CNTs) have superior mechanical and electrical properties that have opened up many potential applications. However, poor dispersibility and solubility, due to the substantial van der Waals attraction between tubes, have prevented the use of CNTs in practical applications, especially biotechnology applications. Effective dispersion of CNTs into small bundles or individual tubes in solvents is crucial to ensure homogeneous properties and enable practical applications. In addition to dispersion of CNTs into a solvent, the selection of appropriate solvent, which is compatible with a desired matrix, is an important factor to improve the mechanical, thermal, optical, and electrical properties of CNT-based fibers and composites. In particular, dispersion of CNTs into an aqueous system has been a challenge due to the hydrophobic nature of CNTs. Here we show an effective method for dispersion of both single wall CNTs (SWCNTs) and few wall CNTs (FWCNTs) in an aqueous buffer solution. We also show an assembly of cationized Pt-cored ferritins on the well dispersed CNTs in an aqueous buffer solution.

  16. Analytical solution of geological carbon sequestration under constant pressure injection into a horizontal radial reservoir

    NASA Astrophysics Data System (ADS)

    Jhang, R.; Liou, T.

    2013-12-01

    Carbon capture and sequestration (CCS) is believed to be an economically feasible technology to mitigate global warming by capturing carbon dioxide (CO2), the major component of greenhouse gases, from the atmosphere and injecting it into deep geological formations.Several mechanisms can help trap CO2 in the pore space of a geological reservoir, stratigraphic and structural trapping, hydrodynamic trapping, and geochemical trapping.Besides these trapping mechanisms, another important issue that deserves careful attention is the risk of CO2 leakage. The common ';constant injection rate' scenario may induce high pressure buildup that will endanger the mechanical integrity as well as the sealing capability of the cap rock. Instead of injecting CO2 at a constant mass rate, CO2 can be injected into the reservoir by fixing the pressure (usually the bottom-hole pressure) in the injection borehole. By doing so, the inevitable pressure buildup associated with the constant injection scheme can be completely eliminated in the constant pressure injection scheme. In this paper, a semi-analytical solution for CO2 injection with constant pressure was developed. For simplicity, structural and geochemical trapping mechanisms were not considered. Therefore, a horizontal reservoir with infinite radial extent was considered. Prior to injection, the reservoir is fully saturated with the formation brine. It is assumed that CO2 does not mix with brine such that a sharp interface is formed once CO2 invades the brine-saturated pores. Because of the density difference between CO2 and brine, CO2 resides above the interface. Additional assumptions were also made when building up the brine and CO2 mass balance equations: (1) both of the fluids and the geological formations are incompressible, (2) capillary pressure is neglected, (3)there is no fluid flow in the vertical direction, and the horizontal flow satisfies the Darcy's law.In order to solve for the height of brine-CO2 interface, the two

  17. Superlubricity achieved with mixtures of polyhydroxy alcohols and acids.

    PubMed

    Li, Jinjin; Zhang, Chenhui; Luo, Jianbin

    2013-04-30

    In the present work, we show that the superlubricity can be achieved when the polyhydroxy alcohol solutions are mixed with acid solutions. The lowest friction coefficients between 0.003 and 0.006 are obtained on a traditional tribometer with a high pressure under the lubrication of these mixtures. Experimental results indicate that the superlubricity mechanism is in accordance with that under the lubrication of the mixture of glycerol and acid solutions in the study by Li et al. (Li , J. J.; Zhang, C. H.; Ma, L. R.; Liu, Y. H.; Luo, J. B. Superlubricity achieved with mixtures of acids and glycerol. Langmuir 2013, 29, 271-275). It is also found that the superlubricity is closely dependent upon the concentration of polyhydroxy alcohol and the number of hydroxyl groups in the molecular structure of polyhydroxy alcohol. However, the number of carbon atoms and the arrangement of hydroxyl groups in the molecular structure almost have no effect on superlubricity.

  18. X-ray diffraction study of the molecular propolis films deposited from an alcohol solution onto the cleavage surfaces of layered V2VI3 compounds

    NASA Astrophysics Data System (ADS)

    Drapak, S. I.; Gavrylyuk, S. V.; Kaminskii, V. M.; Kovalyuk, Z. D.

    2008-09-01

    The structures of the molecular propolis films deposited from an alcohol solution on the (0001) cleavage surface of layered bismuth selenide and telluride are studied by X-ray diffraction. Despite the chemical interaction between the semiconductor substrates and the organic-substance components, the molecular structural ordering of the propolis films is shown to be identical to that in the films of this substance on the surface of amorphous glass substrates. The chemical and deformation interaction between the organic substance and the layered V2VI3 compounds is found to result in the formation of an organic-inorganic sandwich nanostructure at a distance of ˜0.3 μm from the layered crystal-propolis film interface.

  19. Formation of cerussite and hydrocerussite during adsorption of lead from aqueous solution on oxidized carbons by cold oxygen plasma

    NASA Astrophysics Data System (ADS)

    De Velasco Maldonado, Paola S.; Hernández-Montoya, Virginia; Concheso, A.; Montes-Morán, Miguel A.

    2016-11-01

    A new procedure of elimination of Pb2+ from aqueous solution using carbon adsorbents, in which high amounts of cerussite and hydrocerussite are deposited on the carbon surfaces, is reported. The procedure includes the preparation of carbons from selected lignocellulosic wastes (pecan nut shells and peach stones) by single carbonization and further oxidation with cold oxygen plasma. The materials prior and after the oxidation treatment were characterized using elemental analysis, FT-IR spectroscopy, SEM/EDX analysis, adsorption of N2 at -196 °C and X-ray photoelectron spectroscopy. The adsorption of Pb2+ was carried out in batch systems under constant agitation. The formation of cerussite and hydrocerussite on the spent carbon surfaces was confirmed by XRD, SEM/EDX and FT-IR. A Pb2+ removal mechanism is proposed in which a co-precipitation of lead nitrate and calcium carbonate would render the formation of the lead carbonates. In such mechanism, the occurrence of CaCO3 on the surface of the adsorbents plays a crucial role. The presence of calcium carbonate on the precursors is understood on the basis of the thermal evolution of calcium oxalate originally present in the biomass. The oxygen plasma treatment helps to expose the calcium carbonate nanocrystals thus improving dramatically the removal capacity of Pb2+. Accordingly, retention capacities as high as 63 mg of Pb2+ per gram of adsorbent have been attained.

  20. Alcohol Alert: Genetics of Alcoholism

    MedlinePlus

    ... and Reports » Alcohol Alert » Alcohol Alert Number 84 Alcohol Alert Number 84 Print Version The Genetics of ... immune defense system. Genes Encoding Enzymes Involved in Alcohol Breakdown Some of the first genes linked to ...

  1. Spectroscopic and electrochemical studies of selected lanthanides and actinides in concentrated aqueous carbonate and carbonate-hydroxide solutions and in molten dimethyl sulfone

    SciTech Connect

    Varlashkin, P.G.

    1985-03-01

    Electrochemical and spectroscopic studies of neptunium, plutonium, americium, californium, and terbium in concentrated aqueous carbonate and carbonate-hydroxide solutions have been carried out. Changes in the absorption spectra of Np(VII), Np(V), Pu(VI), Pu(V), Am(VI), and Am(V) in concentrated Na/sub 2/CO/sub 3/ solution and in the formal potentials of the Np(VI)/Np(V) and Pu(VI)/Pu(V) couples as a function of pH were observed. Heptavalent neptunium in concentrated Na/sub 2/CO/sub 3/ solution could only be producted at pH values close to or greater than 14. Plutonium(VII) in 2 M Na/sub 2/CO/sub 3/ solution could only be produced at hydroxide ion concentrations in excess of about 2.5 M. The complexation of Np(VII) and Pu(VII) in Na/sub 2/CO/sub 3/-NaOH solution seems to be mainly by hydroxide ions. Neptunium(IV) and plutonium(IV) are insoluble in Na/sub 2/CO/sub 3/ solution above ca. pH 11-12. Neptunium(III) in carbonate solution is rapidly oxidized by water to Np(IV). Plutonium(III) is insoluble in Na/sub 2/CO/sub 3/ solution. In K/sub 2/CO/sub 3/ solution Pu(III) is stable to oxidation by water but is very sensitive to air oxidation. The redox properties of Cf(III) in Na/sub 2/CO/sub 3/ and K/sub 2/CO/sub 3/ solutions at pH values from 8 to 14 were investigated. The oxidation of terbium(III) in K/sub 2/CO/sub 3/-KOH solution was studied. Spectroscopic and electrochemical studies of cerium, samarium, europium, ytterbium, uranium, neptunium, plutonium, and americium in molten dimethyl sulfone (DMSO/sub 2/) at 400 K were performed. Differences in the DMSO/sub 2/ solution absorption spectra of trivalent Sm, Eu, and Yb and divalent Eu compared with those in aqueous solution were observed. Complexation effects on the spectra of Ce(III), Ce(IV), U(VI), Np(VI), Pu(VI), and Am(VI) are more noticeable in poorly coordinating DMSO/sub 2/ than they are in water. 123 references, 54 figures, 11 tables.

  2. Ca-Rich Carbonate Melts: A Regular-Solution Model, with Applications to Carbonatite Magma + Vapor Equilibria and Carbonate Lavas on Venus

    NASA Technical Reports Server (NTRS)

    Treiman, Allan H.

    1995-01-01

    A thermochemical model of the activities of species in carbonate-rich melts would be useful in quantifying chemical equilibria between carbonatite magmas and vapors and in extrapolating liquidus equilibria to unexplored PTX. A regular-solution model of Ca-rich carbonate melts is developed here, using the fact that they are ionic liquids, and can be treated (to a first approximation) as interpenetrating regular solutions of cations and of anions. Thermochemical data on systems of alkali metal cations with carbonate and other anions are drawn from the literature; data on systems with alkaline earth (and other) cations and carbonate (and other) anions are derived here from liquidus phase equilibria. The model is validated in that all available data (at 1 kbar) are consistent with single values for the melting temperature and heat of fusion for calcite, and all liquidi are consistent with the liquids acting as regular solutions. At 1 kbar, the metastable congruent melting temperature of calcite (CaCO3) is inferred to be 1596 K, with (Delta)bar-H(sub fus)(calcite) = 31.5 +/- 1 kJ/mol. Regular solution interaction parameters (W) for Ca(2+) and alkali metal cations are in the range -3 to -12 kJ/sq mol; W for Ca(2+)-Ba(2+) is approximately -11 kJ/sq mol; W for Ca(2+)-Mg(2+) is approximately -40 kJ/sq mol, and W for Ca(2+)-La(3+) is approximately +85 kJ/sq mol. Solutions of carbonate and most anions (including OH(-), F(-), and SO4(2-)) are nearly ideal, with W between 0(ideal) and -2.5 kJ/sq mol. The interaction of carbonate and phosphate ions is strongly nonideal, which is consistent with the suggestion of carbonate-phosphate liquid immiscibility. Interaction of carbonate and sulfide ions is also nonideal and suggestive of carbonate-sulfide liquid immiscibility. Solution of H2O, for all but the most H2O-rich compositions, can be modeled as a disproportionation to hydronium (H3O(+)) and hydroxyl (OH(-)) ions with W for Ca(2+)-H3O(+) (approximately) equals 33 kJ/sq mol. The

  3. Activated carbons from potato peels: The role of activation agent and carbonization temperature of biomass on their use as sorbents for bisphenol A uptake from aqueous solutions

    NASA Astrophysics Data System (ADS)

    Arampatzidou, An; Deliyanni, Eleni A.

    2015-04-01

    Activated carbons prepared from potato peels, a solid waste by product, and activated with different activating chemicals, have been studied for the adsorption of an endocrine disruptor (Bisphenol-A) from aqueous solutions. The potato peels biomass was activated with phosphoric acid, KOH and ZnCl2. The different activating chemicals were tested in order the better activation agent to be found. The carbons were carbonized by pyrolysis, in one step procedure, at three different temperatures in order the role of the temperature of carbonization to be pointed out. The porous texture and the surface chemistry of the prepared activated carbons were characterized by Nitrogen adsorption (BET), Scanning Electron Microscope (SEM), thermal analysis (DTA) and Fourier Transform Infrared Spectroscopy (FTIR). Batch experiments were performed to investigate the effect of pH, the adsorbent dose, the initial bisphenol A concentration and temperature. Equilibrium adsorption data were analyzed by Langmuir and Freundlich isotherms. The thermodynamic parameters such as the change of enthalpy (ΔH0), entropy (ΔS0) and Gibb's free energy (ΔG0) of adsorption systems were also evaluated. The adsorption capacity calculated from the Langmuir isotherm was found to be 450 mg g-1 at an initial pH 3 at 25 °C for the phosphoric acid activated carbon, that make the activated carbon a promising adsorbent material.

  4. Functionalization of Multiwalled Carbon Nanotubes by Solution Plasma Processing in Ammonia Aqueous Solution and Preparation of Composite Material with Polyamide 6

    NASA Astrophysics Data System (ADS)

    Shirafuji, Tatsuru; Noguchi, Yohei; Yamamoto, Taibou; Hieda, Junko; Saito, Nagahiro; Takai, Osamu; Tsuchimoto, Akiharu; Nojima, Kazuhiro; Okabe, Youji

    2013-12-01

    Solution plasma processing (SPP) has been performed on multiwalled carbon nanotubes (MWCNTs) in ammonia aqueous solution. The MWCNTs, which do not disperse in aqueous solution, uniformly dispersed after the SPP. Only 2 h was required to obtain 10 g of the dispersed MWCNTs, while 7 days and additional chemicals were required for 185 mg in a previous study. The X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy of the SPP-treated MWCNTs revealed that nitrogen- and oxygen-containing groups are formed on the MWCNTs. Serious damage to the MWCNT structure was not observed in the Raman spectrum or transmission electron microscopy images of the SPP-treated MWCNTs. The composite materials prepared using polyamide 6 with the SPP-treated MWCNTs showed better tensile, bending, and impact strength than those prepared with nontreated MWCNTs.

  5. Chemisorption of Perfluorooctanoic Acid on Powdered Activated Carbon Initiated by Persulfate in Aqueous Solution.

    PubMed

    Sun, Bo; Ma, Jun; Sedlak, David L

    2016-07-19

    Perfluorooctanoic acid (PFOA) is a perfluorocarboxylic acid that is difficult to treat by most conventional methods. As a result, it is often removed from solution by adsorption on powdered activated carbon (PAC), followed by incineration of the spent carbon. To provide a new approach for treatment, PFOA was exposed to sulfate radicals (SO4(-•)) produced by thermolysis of persulfate (S2O8(2-)) in the presence of PAC. Under acidic conditions, thermal activation of persulfate resulted in transformation of PFOA to shorter-chain-length perfluorinated compounds, as previously reported. However, when thermolysis of persulfate occurred under circumneutral pH conditions in the presence of PAC, a new removal pathway for PFOA was observed. Under these conditions, the removal of PFOA was attributable to chemisorption, a process in which PAC catalyzed persulfate decomposition and reacted with the transformation products to produce covalently bound PFOA. At PAC concentrations between 200 and 1000 mg/L and an initial PFOA concentration of 0.5 μM, covalent bonding resulted in removal of 10-40% of the PFOA. Under these conditions, the process resulted in removal of more than half of a more hydrophilic perfluoroalkyl acid (i.e., perfluorobutanoic acid, PFBA), which was greater than the amount of PFBA removed by physical adsorption on PAC. Although the high reaction temperatures (i.e., 80 °C) and relatively high doses of PAC used in this study may be impractical for drinking water treatment, this process may be applied to the treatment of these recalcitrant compounds in industrial wastewater, reverse osmosis concentrate, and other waters that contain high concentrations of PFOA and other perfluorocarboxylic acids. PMID:27336204

  6. Towards the experimental decomposition rate of carbonic acid (H2CO3) in aqueous solution.

    PubMed

    Tautermann, Christofer S; Voegele, Andreas F; Loerting, Thomas; Kohl, Ingrid; Hallbrucker, Andreas; Mayer, Erwin; Liedl, Klaus R

    2002-01-01

    Dry carbonic acid has recently been shown to be kinetically stable even at room temperature. Addition of water molecules reduces this stability significantly, and the decomposition (H2CO3 + nH2O --> (n+1)H2O + CO2) is extremely accelerated for n = 1, 2, 3. By including two water molecules, a reaction rate that is a factor of 3000 below the experimental one (10 s(-1)) at room temperature was found. In order to further remove the gap between experiment and theory, we increased the number of water molecules involved to 3 and took into consideration different mechanisms for thorough elucidation of the reaction. A mechanism whereby the reaction proceedes via a six-membered transition state turns out to be the most efficient one over the whole examined temperature range. The determined reaction rates approach experimental values in aqueous solution reasonably well; most especially, a significant increase in the rates in comparison to the decomposition reaction with fewer water molecules is found. Further agreement with experiment is found in the kinetic isotope effects (KIE) for the deuterated species. For water-free carbonic acid, the KIE (i.e., kH2CO3/kD2CO3) for the decomposition reaction is predicted to be 220 at 300 K, whereas it amounts to 2.2-3.0 for the investigated mechanisms including three water molecules. This result is therefore reasonably close to the experimental value of 2 (at 300 K). These KIEs are in much better accordance with the experiment than the KIE for decomposition with fewer water entities. PMID:11822465

  7. Fabrication of transparent and conductive carbon nanotube/polyvinyl butyral films by a facile solution surface dip coating method.

    PubMed

    Li, Yuanqing; Yu, Ting; Pui, Tzesian; Chen, Peng; Zheng, Lianxi; Liao, Kin

    2011-06-01

    We present a simple solution surface dip coating method for fabricating transparent and conductive carbon nanotube/polyvinyl butyral (CNT/PVB) composite films. This fabrication process is simple to scale production and requires only ethanol and water as solvents, which is green and environment friendly.

  8. Formation of nanometric HT-LiCoO(2) by a precipitation and aging process in an alcoholic solution.

    PubMed

    Larcher, Dominique; Delobel, Bruno; Dantras-Laffont, Lydia; Simon, Evelyne; Blach, Jean-François; Baudrin, Emmanuel

    2010-12-01

    In this paper, we detailed the formation/evolution of precipitates in alcoholic media containing Co(II+) and Li(+) species, together with the evolution of the composition and structure/texture of the resulting solid phases during the aging process at controlled constant temperature. While the end product is found to be well-crystallized HT-LiCoO(2), its formation is shown to result from a two-step process enlisting the initial fast precipitation of β-HCoO(2) and then its slow dissolution followed by recrystallization of the lithium-containing material. These results were obtained through combined X-ray diffraction, Raman and IR spectroscopy, elemental and oxidation-state analysis, and high-resolution transmission electron microscopy/selected-area electron diffraction observations. Depending on the cationic concentration, the size of the precipitated material can be controlled within the nanometric range. The electrochemical performances of these aged materials are slightly improved compared to those of the directly precipitated ones that we previously reported. The main limitation of these materials remains the presence of surface protons.

  9. Experimental and Theoretical Studies of the Acid-Catalyzed Conversion of Furfuryl Alcohol to Levulinic Acid in Aqueous Solution

    SciTech Connect

    González Maldonado, Gretchen M.; Assary, Rajeev S.; Dumesic, James; Curtiss, Larry A.

    2012-01-01

    The conversion of furfuryl alcohol (FAL) to levulinic acid over AmberlystTM 15 in aqueous media was investigated using a combination of liquid chromatography-mass spectrometry (LC-MS) measurements, isotopic labeling studies, nuclear magnetic resonance (NMR) spectroscopy, and ab initio quantum chemical calculations using the G4MP2 method. The results of these combined studies showed that one of the major reaction pathways takes place via a geminal diol species (4,5,5-trihydroxypentan-2-one, denoted as intermediate A), formed by the addition of two water molecules to FAL, where two of the oxygen atoms from FAL are retained. This geminal diol species can also be produced from another intermediate found to be a dimer-like species, denoted as intermediate B. This dimer-like species is formed at the early stages of reaction, and it can also be converted to intermediate A, indicating that intermediate B is the product of the reaction of FAL with another early intermediate. Quantum chemical calculations suggested this to be a protonated acyclic species. Reaction of this early intermediate with water produces intermediate A, while reaction with FAL produces intermediate B.

  10. Troubled families and individualised solutions: an institutional discourse analysis of alcohol and drug treatment practices involving affected others.

    PubMed

    Selbekk, Anne Schanche; Sagvaag, Hildegunn

    2016-09-01

    Research shows that members of the families with patients suffering from alcohol and other drug-related issues (AOD) experience stress and strain. An important question is, what options do AOD treatment have for them when it comes to support? To answer this, we interviewed directors and clinicians from three AOD treatment institutions in Norway. The study revealed that family-oriented practices are gaining ground as a 'going concern'. However, the relative position of family-orientation in the services, is constrained and shaped by three other going concerns related to: (i) discourse on health and illness, emphasising that addiction is an individual medical and psychological phenomenon, rather than a relational one; (ii) discourse on rights and involvement, emphasising the autonomy of the individual patient and their right to define the format of their own treatment; and (iii) discourse on management, emphasising the relationship between cost and benefit, where family-oriented practices are defined as not being cost-effective. All three discourses are connected to underpin the weight placed on individualised practices. Thus, the findings point to a paradox: there is a growing focus on the needs of children and affected family members, while the possibility of performing integrated work on families is limited.

  11. Electrochemical Sensing and Assessment of Parabens in Hydro-Alcoholic Solutions and Water Using a Boron-Doped Diamond Electrode

    PubMed Central

    Radovan, Ciprian; Cinghiță, Dan; Manea, Florica; Mincea, Manuela; Cofan, Codruța; Ostafe, Vasile

    2008-01-01

    In this paper, the electrochemical behaviour of several parabens preservatives, i.e. esters of p-hydroxybenzoic acid, methyl-, ethyl- and propyl-4-hydroxybenzoates as methyl-, ethyl- and propyl-parabens (MB, EB, and PB), has been investigated at a commercial boron-doped diamond electrode (BDDE), especially in the anodic potential range, in both hydro-alcoholic and aqueous media. The cyclic voltammetric and chronoamperometric measurements yielded calibration plots with very good linearity (R2 between 0.990 and 0.998) and high sensitivity, useful for detection and analytical applications. The determination of the characteristics of individual compounds, of an “overall paraben index”, the assessment of the stability and the saturation solubility in water, and the amperometric sensing and determination in double distilled, tap and river water matrix of the relatively slightly soluble investigated parabens have been carried out using electrochemical alternative. Estimated water solubility was correlated with the octanol-water partition coefficient. Several ideas regarding stability and persistence of the presumptive eco-toxic investigated preservatives in the environment or water systems have been adjacently discussed.

  12. Polymorph selection and nanocrystallite rearrangement of calcium carbonate in carboxymethyl chitosan aqueous solution: Thermodynamic and kinetic analysis

    SciTech Connect

    Zhao, Donghui; Zhu, Yingchun; Li, Fang; Ruan, Qichao; Zhang, Shengmao; Zhang, Linlin; Xu, Fangfang

    2010-01-15

    In this article, the polymorph selection of calcium carbonate has been successfully achieved in water-soluble carboxymethyl chitosan aqueous solution at different temperatures (25-95 {sup o}C). Vaterite is formed in carboxymethyl chitosan solution 25 {sup o}C accompanied with trace of calcite, whereas pure aragonite is obtained at 95 {sup o}C. Scanning electron microscopy and transmission electron microscopy analyses show that the products are formed from the recrystallization of nanometer crystallites. Thermodynamic and kinetic analyses reveal that the polymorph of calcium carbonate is controlled and selected by kinetics in various temperatures. As a heterogeneous nucleator and stabilizing agent, carboxymethyl chitosan changes the nucleation and growth of calcium carbonate from thermodynamic into kinetic control. Under kinetic limitation, the reaction rate of aragonite increases along with the elevating of temperature and surpasses the rate of vaterite above 327 K.

  13. Characterization of atomic structure of oxide films on carbon steel in simulated concrete pore solutions using EELS

    NASA Astrophysics Data System (ADS)

    Gunay, H. Burak; Ghods, Pouria; Isgor, O. Burkan; Carpenter, Graham J. C.; Wu, Xiaohua

    2013-06-01

    The atomic structure of oxide films formed on carbon steel that are exposed to highly alkaline simulated concrete pore solutions was investigated using Electron Energy Loss Spectroscopy (EELS). In particular, the effect of chloride exposure on film structure was studied in two types of simulated pore solutions: saturated calcium hydroxide (CH) and a solution prepared to represent typical concrete pore solutions (CP). It was shown that the films that form on carbon steel in simulated concrete pore solutions contained three indistinct layers. The inner oxide film had a structure similar to that of FeIIO, which is known to be unstable in the presence of chlorides. The outer oxide film mainly resembled Fe3O4 (FeIIO·Fe2IIIO3) in the CH solution and α-Fe2IIIO3/Fe3O4 in the CP solution. The composition of the transition layer between the inner and outer layers of the oxide film was mainly composed of Fe3O4 (FeIIO·Fe2IIIO3). In the presence of chloride, the relative amount of the FeIII/FeII increased, confirming that chlorides induce valence state transformation of oxides from FeII to FeIII, and the difference between the atomic structures of oxide film layers diminished.

  14. A Search for Interstellar Carbon-chain Alcohol HC4OH in Star-forming Region l1527 and Dark Cloud TMC-1

    NASA Astrophysics Data System (ADS)

    Araki, Mitsunori; Takano, Shuro; Yamabe, Hiromichi; Koshikawa, Naohiro; Tsukiyama, Koichi; Nakane, Aya; Okabayashi, Toshiaki; Kunimatsu, Arisa; Kuze, Nobuhiko

    2012-01-01

    We report a sensitive search for the rotational transitions of the carbon-chain alcohol HC4OH in the frequency range 21.2-46.7 GHz in the star-forming region L1527 and the dark cloud TMC-1. The motivation was laboratory detection of HC4OH by microwave spectroscopy. Despite achieving rms noise levels of several millikelvin in the antenna temperature using the 45 m telescope at Nobeyama Radio Observatory, the detection was not successful, leading to 3σ upper limits corresponding to the column densities of 2.0 × 1012 and 5.6 × 1012 cm-2 in L1527 and TMC-1, respectively. These upper limits indicate that [HC4OH]/[HC5N] ratios are less than 0.3 and 0.1 in L1527 and TMC-1, respectively, where HC5N is an HC4-chain cyanide and HC4OH is a hydroxide. These ratios suggest that the cyano carbon-chain molecule dominates the hydroxyl carbon-chain molecule in L1527 and TMC-1. This is contrary to the case of saturated compounds in hot cores, e.g., CH3OH and CH3CN, and can be a chemical feature of carbon-chain molecules in L1527 and TMC-1. In addition, the column densities of the "unsubstituted" carbon-chain molecule C4H and the sulfur-bearing molecules SO and HCS+ were determined from detected lines in L1527.

  15. Study of benzotriazole as corrosion inhibitors of carbon steel in chloride solution containing hydrogen sulfide using electrochemical impedance spectroscopy (EIS)

    NASA Astrophysics Data System (ADS)

    Solehudin, Agus; Nurdin, Isdiriayani

    2014-03-01

    Corrosion and inhibition studies on API 5LX65 carbon steel in chloride solution containing various concentrations of benzotriazole has been conducted at temperature of 70°C using Electrochemical Impedance Spectroscopy (EIS). Corroded carbon steel surface with and without inhibitor have been observed using X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), and Energy Dispersive Spectroscopy (EDS). The objectives of this research are to study the performance of benzotriazole as corrosion inhibitors. The experimental results of carbon steel corrosion in 3.5% NaCl solution containing 500 mg/l H2S at different BTAH concentrations showed that corrosion rate of carbon steel decreases with increasing of BTAH concentrations from 0 to 10 mmol/l. The inhibition efficiency of BTAH was found to be affected by its concentration. The optimum efficiency obtained of BTAH is 93% at concentration of 5 mmol/l. The result of XRD and EDS analysis reveal the iron sulfide (FeS) formation on corroded carbon steel surface without inhibitor. The EDS spectrum show the Nitrogen (N) bond on carbon steel surface inhibited by BTAH.

  16. Calcium-magnesium carbonate solid solutions from Holocene conglomerate cements and travertines in the Coast Range of California

    USGS Publications Warehouse

    Barnes, I.; O'Neil, J.R.

    1971-01-01

    Two calcium-magnesium carbonate solid solutions form Holocene travertines and conglomerate cements in fresh water stream channels of the Coast Range of California. Calcite does not yield the {015} diffraction maximum. The {006} diffraction maximum is lacking over most of the range of composition of calcite. Calcite has compositions from CaCO3 to Ca0.5Mg0.5CO3. Dolomite yields both the {006} and {015} diffraction maxima over its entire composition range, Ca0.6Mg0.4CO3 to Ca0.5Mg0.5CO3. The Ca-Mg carbonates form in isotopic equilibrium and thermodynamic disequilibrium from dispersion of Ca2+-rich water into CO32--rich water within the alluvium. The stable isotope data suggest that all the Mg-rich carbonates are primary precipitates and not a result of Mg-substitution in precursor CaCO3. There is a correlation between ??C13 and Mg content of the carbonates which predicts a 5%. fractionation of C13 between dolomite and calcite at sedimentary temperatures. C14 is incorporated in Ca-Mg carbonates forming from C13-poor meteoric waters and C13-rich waters from Cretaceous sediments. C14 ages of the Ca-Mg carbonates are apparent, and cannot be corrected to absolute values. Solution rates of calcite decrease with increasing MgCO3 content; dolomite dissolves slower than any calcite. ?? 1971.

  17. Study of benzotriazole as corrosion inhibitors of carbon steel in chloride solution containing hydrogen sulfide using electrochemical impedance spectroscopy (EIS)

    SciTech Connect

    Solehudin, Agus; Nurdin, Isdiriayani

    2014-03-24

    Corrosion and inhibition studies on API 5LX65 carbon steel in chloride solution containing various concentrations of benzotriazole has been conducted at temperature of 70°C using Electrochemical Impedance Spectroscopy (EIS). Corroded carbon steel surface with and without inhibitor have been observed using X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), and Energy Dispersive Spectroscopy (EDS). The objectives of this research are to study the performance of benzotriazole as corrosion inhibitors. The experimental results of carbon steel corrosion in 3.5% NaCl solution containing 500 mg/l H{sub 2}S at different BTAH concentrations showed that corrosion rate of carbon steel decreases with increasing of BTAH concentrations from 0 to 10 mmol/l. The inhibition efficiency of BTAH was found to be affected by its concentration. The optimum efficiency obtained of BTAH is 93% at concentration of 5 mmol/l. The result of XRD and EDS analysis reveal the iron sulfide (FeS) formation on corroded carbon steel surface without inhibitor. The EDS spectrum show the Nitrogen (N) bond on carbon steel surface inhibited by BTAH.

  18. Biomass waste-derived activated carbon for the removal of arsenic and manganese ions from aqueous solutions

    NASA Astrophysics Data System (ADS)

    Budinova, T.; Savova, D.; Tsyntsarski, B.; Ania, C. O.; Cabal, B.; Parra, J. B.; Petrov, N.

    2009-02-01

    The goal of this study is to investigate the preparation of low-cost activated carbon from bean pods waste and to explore their potential application for the removal of heavy metals from aqueous solutions. Conventional physical (water vapor) activation was used for synthesizing the adsorbent. The obtained carbon was employed for the removal of As (III) and Mn (II) from aqueous solutions at different initial concentrations and pH values. Adsorption for both ions follows Langmuir-type isotherm, the maximum loading capacities for arsenic (III) and Mn (II) ions being 1.01 and 23.4 mg g -1, respectively. According to the experimental data, it can be inferred that the basic character of the surface, i.e. the high content of basic groups, favors adsorption of ions. Arsenic adsorption capacity on the carbon obtained from agricultural waste was found to be similar to this of more expensive commercial carbons showing high adsorption capability. Regarding manganese adsorption, herein obtained carbon presented higher uptake adsorption than that of activated carbons reported in the literature.

  19. Metallocoenzyme-mediated reductive transformation of carbon tetrachloride in titanium (III) citrate aqueous solution

    SciTech Connect

    Chiu, P.C.; Reinhard, M.

    1995-03-01

    Transformation pathways for carbon tetrachloride (CCl{sub 4}) catalyzed by hematin or vitamin B{sub 12} in aqueous titanium(III) citrate solution are proposed. The reaction of CCl{sub 4} with B{sub 12} was zero order in CCl{sub 4} and first order in B{sub 12}, and the rate constant was measured from pH 7.3 to pH 10.3. The proposed rate-limiting step is the reduction of the stable trichloromethylcobalamin (CCl{sub 3}-Cbl) intermediate by titanium(III) citrate at alkaline pH and the sterically induced CCl{sub 3}-Cbl decomposition at neutral pH. The reaction kinetics can be described by a modified Michaelis-Menten model in the saturated regime. With hematin, only the pseudo-first-order rate constant was determined due to the significant deactivation of the coenzyme. The turnover number of hematin (molecules of CCl{sub 4} transformed/molecule of hematin deactivated) was 27 at pH 8.0 and 42 at pH 9.9. Vitamin B{sub 12} was a more stable and more effective catalyst (on a molar basis) than hematin with respect to CCl{sub 4}. Chloroform (CHCl{sub 3}) was the primary product in titanium(III) citrate solution, and the yield was a function of pH, Ti(III) concentration, and organic content regardless of whether a coenzyme was present or which coenzyme was used. Although B{sub 12} and hematin can both enhance the CCl{sub 4} transformation rate, they have little effect on the CHCl{sub 3} yield. Titanium(III) citrate, on the other hand, controls not only the transformation rate but also CHCl{sub 3} formation. 77 refs., 10 figs.

  20. Ciprofloxacin adsorption on graphene and granular activated carbon: kinetics, isotherms, and effects of solution chemistry.

    PubMed

    Zhu, Xuan; Tsang, Daniel C W; Chen, Feng; Li, Shiyu; Yang, Xin

    2015-01-01

    Ciprofloxacin (CIP) is a commonly used antibiotic and widely detected in wastewaters and farmlands nowadays. This study evaluated the efficacy of next-generation adsorbent (graphene) and conventional adsorbent (granular activated carbon, GAC) for CIP removal. Batch experiments and characterization tests were conducted to investigate the adsorption kinetics, equilibrium isotherms, thermodynamic properties, and the influences of solution chemistry (pH, ionic strength, natural organic matter (NOM), and water sources). Compared to GAC, graphene showed significantly faster adsorption and reached equilibrium within 3 min, confirming the rapid access of CIP into the macroporous network of high surface area of graphene as revealed by the Brunner-Emmet-Teller measurements analysis. The kinetics was better described by a pseudo-second-order model, suggesting the importance of the initial CIP concentration related to surface site availability of graphene. The adsorption isotherm on graphene followed Langmuir model with a maximum adsorption capacity of 323 mg/g, which was higher than other reported carbonaceous adsorbents. The CIP adsorption was thermodynamically favourable on graphene and primarily occurred through π - π interaction, according to the FTIR spectroscopy. While the adsorption capacity of graphene decreased with increasing solution pH due to the speciation change of CIP, the adverse effects of ionic strength (0.01-0.5 mol L(-1)), presence of NOM (5 mg L⁻¹), and different water sources (river water or drinking water) were less significant on graphene than GAC. These results indicated that graphene can serve as an alternative adsorbent for CIP removal in commonly encountered field conditions, if proper separation and recovery is available in place. PMID:26050736

  1. Influence of different alcohols on the swelling behaviour of hydrogels

    NASA Astrophysics Data System (ADS)

    Althans, Daniel; Langenbach, Kai; Enders, Sabine

    2012-06-01

    The swelling equilibrium of cross-linked poly(N-isopropylacrylamide) (PNIPAAm) hydrogels in alcohol solutions as a function of temperature, alcohol concentration, kind of alcohol (C1OH-C3OH) and gel properties was investigated experimentally. Additionally, the swelling degree as a function of the alcohol concentration was modelled with the UNIQUAC-Free Volume model in combination with the Phantom Network theory. The experiments show that, in pure water, the transition temperature is between 303.15 and 308.15 K depending on the properties of the gel and hence on the polymerization conditions. The transition from a swollen to a shrunken state is caused by the polymeric network and the change of polymer chain localization. In a system with hydrogel + water + alcohol, the swelling degree decreases with increasing alcohol concentration until the shrunken state is reached and increases again by further addition of alcohol at constant temperature. With increasing carbon number of the alcohols, the transition from a swollen to a shrunken state and vice versa shifts to lower concentrations at constant temperature. The use of the UNIQUAC-Free Volume model with Phantom Network theory leads to results in good agreement with the experimental data.

  2. Modification of granular activated carbon using low molecular weight polymer for enhanced removal of Cu(2+) from aqueous solution.

    PubMed

    Yin, C Y; Aroua, M K; Daud, W M A W

    2007-01-01

    Palm shell activated carbon was modified via surface impregnation with polyethyleneimine (PEI) to enhance removal of Cu(2+) from aqueous solution in this study. The effect of PEI modification on batch adsorption of Cu(2+) as well as the equilibrium behavior of adsorption of metal ions on activated carbon were investigated. PEI modification clearly increased the Cu(2+) adsorption capacities by 68% and 75.86% for initial solution pH of 3 and 5 respectively. The adsorption data of Cu(2+) on both virgin and PEI-modified AC for both initial solution pH of 3 and 5 fitted the Langmuir and Redlich-Peterson isotherms considerably better than the Freundlich isotherm.

  3. Significant effects of sodium acetate, an impurity present in poly(vinyl alcohol) solution on the radiolytic formation of silver nanoparticle

    NASA Astrophysics Data System (ADS)

    Shin, Junhwa; Kim, Yunhye; Lee, Kiwon; Lim, Youn Mook; Nho, Young Chang

    2008-07-01

    A silver nanoparticle (AgNPs) stabilizer, polyvinyl alcohol (PVA) generally contains a relatively large amount of sodium acetate (NaOAc) as an impurity (up to several weight percentages) as a result of a base-catalyzed hydrolysis of poly(vinyl acetate) (PVAc). In this study, the effects of NaOAc on the radiolytic formation of AgNPs in PVA solutions were studied by using UV/vis spectroscopy. Several AgNPs were prepared by γ-ray irradiation using 60Co source at various doses in the presence of various amounts of NaOAc. The UV data of the AgNPs observed at around 410 nm show that more AgNPs are generally produced as the NaOAc concentration in the PVA solution increases. Furthermore, no significant absorption band of the AgNPs was observed when the purified PVA containing a very small amount of NaOAc (less than 3×10 -4 M) was applied with 1×10 -3 M AgNO 3 up to 10 kGy. These results reveal that NaOAc present as an impurity in PVA, plays an important role in the radiolytic formation of AgNPs.

  4. Extraction of gold(III) from hydrochloric acid solutions by CTAB/n-heptane/iso-amyl alcohol/Na2SO3 microemulsion.

    PubMed

    Lu, Wenjuan; Lu, Yanmin; Liu, Fei; Shang, Kai; Wang, Wei; Yang, Yanzhao

    2011-02-28

    The extraction of Au(III) from hydrochloric acid solutions by microemulsion was studied. The extraction experiments were carried out using cetyltrimethylammonium bromide (CTAB) as surfactant and iso-amyl alcohol as co-surfactant. Au(III) was found to be extracted into the microemulsion phase due to ion pair formation such as AuCl(4)(-)CTAB(+). The influence of temperature on the extraction of Au(III) has been investigated at temperatures ranging from 288 to 313 K. Temperature was found to decrease the distribution of Au(III). Thermodynamic parameters like enthalpy and entropy of the extraction, calculated by applying Van't Hoff equation, were -36.76 kJ mol(-1) and -84.87 J mol(-1) K(-1), respectively. Furthermore, the influence of the concentrations of hydrogen ion and chloride anion on the extraction efficiency (E%) were verified. Au(III) was extracted quantitatively (E%>99%) and selectively at the whole range of HCl concentrations (0.2-5 M). Recovery of gold from electrical waste and treatment of CTAB wastewater generated from the extraction were also discussed. Thus, the extraction of Au(III) from hydrochloric acid solutions by microemulsion is an effective approach.

  5. Stability of fluctuating and transient aggregates of amphiphilic solutes in aqueous binary mixtures: Studies of dimethylsulfoxide, ethanol, and tert-butyl alcohol

    NASA Astrophysics Data System (ADS)

    Banerjee, Saikat; Bagchi, Biman

    2013-10-01

    In aqueous binary mixtures, amphiphilic solutes such as dimethylsulfoxide (DMSO), ethanol, tert-butyl alcohol (TBA), etc., are known to form aggregates (or large clusters) at small to intermediate solute concentrations. These aggregates are transient in nature. Although the system remains homogeneous on macroscopic length and time scales, the microheterogeneous aggregation may profoundly affect the properties of the mixture in several distinct ways, particularly if the survival times of the aggregates are longer than density relaxation times of the binary liquid. Here we propose a theoretical scheme to quantify the lifetime and thus the stability of these microheterogeneous clusters, and apply the scheme to calculate the same for water-ethanol, water-DMSO, and water-TBA mixtures. We show that the lifetime of these clusters can range from less than a picosecond (ps) for ethanol clusters to few tens of ps for DMSO and TBA clusters. This helps explaining the absence of a strong composition dependent anomaly in water-ethanol mixtures but the presence of the same in water-DMSO and water-TBA mixtures.

  6. Common Issues and Collaborative Solutions: A Comparison of Student Alcohol Use Behaviors at the Community College and 4-Year Institutional Levels

    ERIC Educational Resources Information Center

    Blowers, Jerimy

    2009-01-01

    The literature exploring commonalities between four-year and community college student alcohol use is relatively scarce. A possible reason for this discrepancy is the heavy focus on alcohol issues at university colleges. Coll (1999) presented one of the first brief assessments comparing community and four-year colleges on alcohol use and related…

  7. A thermodynamic solution model for calcium carbonate: Towards an understanding of multi-equilibria precipitation pathways.

    PubMed

    Donnet, Marcel; Bowen, Paul; Lemaître, Jacques

    2009-12-15

    Thermodynamic solubility calculations are normally only related to thermodynamic equilibria in solution. In this paper, we extend the use of such solubility calculations to help elucidate possible precipitation reaction pathways during the entire reaction. We also estimate the interfacial energy of particles using only solubility data by a modification of Mersmann's approach. We have carried this out by considering precipitation reactions as a succession of small quasi-equilibrium states. Thus possible equilibrium precipitation pathways can be evaluated by calculating the evolution of surface charge, particle size and/or interfacial energy during the ongoing reaction. The approach includes the use of the Kelvin's law to express the influence of particle size on the solubility constant of precipitates, the use of Nernst's law to calculate surface potentials from solubility calculations and relate this to experimentally measured zeta potentials. Calcium carbonate precipitation and zeta potential measurements of well characterised high purity calcite have been used as a model system to validate the calculated values. The clarification of the change in zeta potential on titration illustrates the power of this approach as a tool for reaction pathway prediction and hence knowledge based tailoring of precipitation reactions.

  8. Removal of boron from aqueous solution using magnetic carbon nanotube improved with tartaric acid.

    PubMed

    Zohdi, Nima; Mahdavi, Fariba; Abdullah, Luqman Chuah; Choong, Thomas Sy

    2014-01-06

    Boron removal capacity of multi-walled carbon nanotubes (MWCNTs) modified with tartaric acid was investigated in this study. Modification of MWCNTs with tartaric acid was confirmed by Boehm surface chemistry method and fourier transform infra-red (FT-IR) spectroscopy. Experiments were performed to determine the adsorption isotherm and adsorption thermodynamic parameters of boron adsorption on tartaric acid modified MWCNTs (TA-MWCNTs). The effect of variables including initial pH, dosage of adsorbent, contact time and temperature was investigated. Analysis of data showed that adsorption equilibrium could be better described by Freundlich isotherm and the maximum adsorption capacities obtained at the pH of 6.0 was 1.97 mg/g. The estimated thermodynamic values of free energy (ΔG°), entropy (ΔS°) and enthalpy (ΔH°) indicated a spontaneous and an endothermic process. Furthermore, the TA-MWCNTs was magnetized for separation of boron-contaminated adsorbent from aqueous solution by applying magnetic field. The results showed that magnetic TA-MWCNTs particles were separated effectively after adsorption from contaminated water.

  9. Oxidized multiwalled carbon nanotubes as adsorbent for the removal of manganese from aqueous solution.

    PubMed

    Ganesan, Pandian; Kamaraj, Ramakrishnan; Sozhan, Ganapathy; Vasudevan, Subramanyan

    2013-02-01

    A batch adsorption process was applied to investigate the removal of manganese from aqueous solution by oxidized multiwalled carbon nanotubes (MWCNTs). In doing so, the thermodynamic, adsorption isotherm, and kinetic studies were also carried out. MWCNT with 5-10-nm outer diameter, surface area of 40-600 m(2)/g, and purity above 95 % was used as an adsorbent. A systematic study of the adsorption process was performed by varying pH, ionic strength, and temperature. Manganese-adsorbed MWCNT was characterized by Raman, FTIR, X-ray diffraction, XPS, SEM, and TEM. The adsorption efficiency could reach 96.82 %, suggesting that MWCNT is an excellent adsorbent for manganese removal from water. The results indicate that second-order kinetics model was well suitable to model the kinetic adsorption of manganese. Equilibrium data were well described by the typical Langmuir adsorption isotherm. Thermodynamic studies revealed that the adsorption reaction was spontaneous and endothermic process. The experimental results showed that MWCNT is an excellent manganese adsorbent. The MWCNTs removed the manganese present in the water and reduced it to a permissible level making it drinkable.

  10. Removal of Chemazol Reactive Red 195 from aqueous solution by dehydrated beet pulp carbon.

    PubMed

    Dursun, Arzu Y; Tepe, Ozlem

    2011-10-30

    An agricultural low-cost by-product, dehydrated beet pulp carbon (DBPC) was used as an adsorbent for removal of Chemazol Reactive Red 195 (CRR 195) from aqueous solution. The surface area of DBPC was measured as 9.5m(2)g(-1) by using BET method. The results indicated that adsorption was strongly pH-dependent and optimum pH was determined as 1.0. The maximum dye adsorption capacity was obtained as 58.0 mg g(-1)at the temperature of 50°C at this pH value. The Freundlich and Langmuir adsorption models were used for the mathematical description of the adsorption equilibrium and it was reported that, experimental data fitted very well to Freundlich model. Mass transfer and kinetic models were applied to the experimental data to examine the mechanisms of adsorption and potential rate-controlling steps. It was found that both external mass transfer and intra-particle diffusion played an important role in the adsorption mechanisms of dye and adsorption kinetics followed the pseudo-first-order type kinetic model. The thermodynamic parameters such as, Gibbs free energy changes (ΔG°), standard enthalpy change (ΔH°) and standard entropy change (ΔS°) had been determined. The results show that adsorption of CRR 195 on DBPC is endothermic and spontaneous in nature. PMID:21890269

  11. Comparative performance of cement kiln dust and activated carbon in removal of cadmium from aqueous solutions.

    PubMed

    El-Refaey, Ahmed A

    2016-01-01

    This study compared the performance of cement kiln dust (CKD) as industrial byproduct and commercially activated carbon (AC) as adsorbent derived from agricultural waste for the removal of cadmium (Cd(2+)) from aqueous solutions. CKD and AC were characterized by Fourier transform infrared (FTIR) and scanning electron microscopy (SEM) and surface areas demonstrate the differences of physicochemical properties. Batch equilibrium experiments were conducted for various intervals extended to 96 h at 20, 25 and 30°C to investigate the efficiency of the sorbents in the removal of Cd(2+). CKD expressed high affinity for removal of Cd(2+) and was not affected by temperature, while AC was significantly affected, which reflects dissimilarity in the retention mechanisms defendant in CKD and those pursued by AC. The results were explained by changes of FTIR and SEM images before and after sorption experiments. The suggestion is that electrostatic ion exchange and complex reactions are the main mechanisms for Cd(2+) removal. The kinetic data were evaluated by fractional power, Elovich, pseudo-first order and pseudo-second-order kinetic models. The pseudo-second-order kinetic model was found to correlate with the experimental data well. These results revealed that CKD can be used as a cost-effective and efficient sorbent for Cd(2+) removal in comparison with AC.

  12. Removal of boron from aqueous solution using magnetic carbon nanotube improved with tartaric acid

    PubMed Central

    2014-01-01

    Boron removal capacity of multi-walled carbon nanotubes (MWCNTs) modified with tartaric acid was investigated in this study. Modification of MWCNTs with tartaric acid was confirmed by Boehm surface chemistry method and fourier transform infra-red (FT-IR) spectroscopy. Experiments were performed to determine the adsorption isotherm and adsorption thermodynamic parameters of boron adsorption on tartaric acid modified MWCNTs (TA-MWCNTs). The effect of variables including initial pH, dosage of adsorbent, contact time and temperature was investigated. Analysis of data showed that adsorption equilibrium could be better described by Freundlich isotherm and the maximum adsorption capacities obtained at the pH of 6.0 was 1.97 mg/g. The estimated thermodynamic values of free energy (ΔG°), entropy (ΔS°) and enthalpy (ΔH°) indicated a spontaneous and an endothermic process. Furthermore, the TA-MWCNTs was magnetized for separation of boron-contaminated adsorbent from aqueous solution by applying magnetic field. The results showed that magnetic TA-MWCNTs particles were separated effectively after adsorption from contaminated water. PMID:24393401

  13. Comparative performance of cement kiln dust and activated carbon in removal of cadmium from aqueous solutions.

    PubMed

    El-Refaey, Ahmed A

    2016-01-01

    This study compared the performance of cement kiln dust (CKD) as industrial byproduct and commercially activated carbon (AC) as adsorbent derived from agricultural waste for the removal of cadmium (Cd(2+)) from aqueous solutions. CKD and AC were characterized by Fourier transform infrared (FTIR) and scanning electron microscopy (SEM) and surface areas demonstrate the differences of physicochemical properties. Batch equilibrium experiments were conducted for various intervals extended to 96 h at 20, 25 and 30°C to investigate the efficiency of the sorbents in the removal of Cd(2+). CKD expressed high affinity for removal of Cd(2+) and was not affected by temperature, while AC was significantly affected, which reflects dissimilarity in the retention mechanisms defendant in CKD and those pursued by AC. The results were explained by changes of FTIR and SEM images before and after sorption experiments. The suggestion is that electrostatic ion exchange and complex reactions are the main mechanisms for Cd(2+) removal. The kinetic data were evaluated by fractional power, Elovich, pseudo-first order and pseudo-second-order kinetic models. The pseudo-second-order kinetic model was found to correlate with the experimental data well. These results revealed that CKD can be used as a cost-effective and efficient sorbent for Cd(2+) removal in comparison with AC. PMID:27054742

  14. Low-cost, solution processable carbon nanotube supercapacitors and their characterization

    NASA Astrophysics Data System (ADS)

    Lehtimäki, Suvi; Tuukkanen, Sampo; Pörhönen, Juho; Moilanen, Pasi; Virtanen, Jorma; Honkanen, Mari; Lupo, Donald

    2014-06-01

    We report ecological and low-cost carbon nanotube (CNT) supercapacitors fabricated using a simple, scalable solution processing method, where the use of a highly porous and electrically conductive active material eliminates the need for a current collector. Electrodes were fabricated on a poly(ethylene terephthalate) substrate from a printable multi-wall CNT ink, where the CNTs are solubilized in water using xylan as a dispersion agent. The dispersion method facilitates a very high concentration of CNTs in the ink. Supercapacitors were assembled using a paper separator and an aqueous NaCl electrolyte and the devices were characterized with a galvanostatic discharge method defined by an industrial standard. The capacitance of the 2 cm^2 devices was 6 mF/cm^2 (2.3 F/g) and equivalent series resistance 80 Ω . Low-cost supercapacitors fabricated from safe and environmentally friendly materials have potential applications as energy storage devices in ubiquitous and autonomous intelligence as well as in disposable low-end products.

  15. Partial carbonized nanoporous resin for uptake of lead from aqueous solution.

    PubMed

    Ghiloufi, I; Al-Hobaib, A S; El Mir, L

    2015-01-01

    Four partial carbonized nanoporous resins (PCNRs), based on organic xerogel compounds, were synthesised by the sol-gel method from pyrogallol and formaldehyde mixtures in water using picric acid as catalyst. The PCNRs were prepared at different pyrolysis temperatures: T(1) = 200 °C (PF-200), T(2) = 300 °C (PF-300), T(3) = 400 °C (PF-400), or T(4) = 500 °C (PF-500). The PCNRs were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier transformed infrared spectroscopy, and nitrogen porosimetry. The obtained results show that PF-200 is more efficient for the removal of Pb(2+) from aqueous solution than the other adsorbent prepared in this study. The characteristics of lead uptake by PF-200 were explored using well-established and effective parameters including pH, contact time, initial metal ion concentration and temperature. Optimum adsorption of Pb(2+), using PF-200, was observed at pH 4.5. The Langmuir model gave a better fit than the other models, and kinetic studies revealed that the adsorption was well fitted by the pseudo second-order kinetic model and thermodynamic properties, i.e., Gibbs free energy change, enthalpy change and entropy change, showed that adsorption of Pb(2+) onto PF-200 was endothermic, spontaneous and feasible in the temperature range of 298-328 K. PMID:26360758

  16. Adsorption of Acid Red 57 from aqueous solutions onto polyacrylonitrile/activated carbon composite.

    PubMed

    El-Bindary, Ashraf A; Diab, Mostafa A; Hussien, Mostafa A; El-Sonbati, Adel Z; Eessa, Ahmed M

    2014-04-24

    The adsorption of Acid Red 57 (AR57) onto Polyacrylonitrile/activated carbon (PAN/AC) composite was investigated in aqueous solution in a batch system with respect to contact time, pH and temperature. Physical characteristics of (PAN/AC) composite such as fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) were obtained. Langmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms and the isotherm constants were determined. The activation energy of adsorption was also evaluated for the adsorption of AR57 onto (PAN/AC) composite. The pseudo-first-order and pseudo-second-order kinetic models were used to describe the kinetic data. The dynamic data fitted the pseudo-second-order kinetic model well. The activation energy, change of free energy, enthalpy and entropy of adsorption were also evaluated for the adsorption of AR57 onto (PAN/AC) composite. The thermodynamics of the adsorption indicated spontaneous and exothermic nature of the process. The results indicate that (PAN/AC) composite could be employed as low-cost material for the removal of acid dyes from textile effluents. PMID:24463242

  17. Arsenic adsorption by polyvinyl pyrrolidone K25 coated cassava peel carbon from aqueous solution.

    PubMed

    Selvakumar, R; Kavitha, S; Sathishkumar, M; Swaminathan, K

    2008-05-01

    Sorption of arsenic from aqueous solution was carried out using polyvinyl pyrrolidone K25 coated cassava peel carbon (PVPCC). Batch experiments were conducted to determine the effect of contact time, initial concentration, pH and desorption. Batch sorption data's were fitted to Lagergren kinetic studies. Column studies were also conducted using PVPCC as adsorbent. The optimized flow rate of 2.5 mL min(-1) and bed height 10 cm were used to determine the effect of metal ion concentration on removal of As(V). BDST model was applied to calculate the adsorption capacity (N(0)) of column. The N(0) value of 2.59 x 10(-5), 4.21 x 10(-5), 4.05 x 10(-5), 4.26 x 10(-5) and 3.2 x 10(-5) mg g(-1) were obtained for 0.5, 1.0, 1.5, 2.0 and 2.5 mg L(-1) of As(V), respectively. The batch sorption proved to be more efficient than the column sorption. The sorption of As(V) and the nature of the adsorbent was examined by Fourier transmission infrared spectroscopy (FTIR) and X-ray diffraction (XRD) studies, respectively.

  18. Degradation of carbon tetrachloride in aqueous solution in the thermally activated persulfate system.

    PubMed

    Xu, Minhui; Gu, Xiaogang; Lu, Shuguang; Qiu, Zhaofu; Sui, Qian; Miao, Zhouwei; Zang, Xueke; Wu, Xiaoliang

    2015-04-01

    Thermal activation of persulfate (PS) has been identified to be effective in the destruction of organic pollutants. The feasibility of carbon tetrachloride (CT) degradation in the thermally activated PS system was evaluated. The experimental results showed that CT could be readily degraded at 50 °C with a PS concentration of 0.5M, and CT degradation and PS consumption followed the pseudo-first order kinetic model. Superoxide radical anion (O2(*-)) was the predominant radical species responsible for CT degradation and the split of CCl was proposed as the possible reaction pathways for CT degradation. The process of CT degradation was accelerated by higher PS dose and lower initial CT concentration. No obvious effect of the initial pH on the degradation of CT was observed in the thermally activated PS system. Cl(*-), HCO3(*-), and humic acid (HA) had negative effects on CT degradation. In addition, the degradation of CT in the thermally activated PS system could be significantly promoted by the solvents addition to the solution. In conclusion, the thermally activated PS process is a promising option in in-situ chemical oxidation/reduction remediation for degrading highly oxidized organic contaminants such as CT that is widely detected in contaminated sites.

  19. Adsorption of organic molecules at the mercury-solution interface: effect of anion specific adsorption on double layer properties. [Benzyl alcohol

    SciTech Connect

    Buckfelder, J.J. III

    1980-08-01

    Adsorption of iso-pentanol, pentanoic acid, and benzyl alcohol at the mercury-solution interface was studied in HC1O/sub 4/, H/sub 2/SO/sub 4/, NaNO/sub 3/, and NaF electrolytes. The Frumkin isotherm equation Ba = (theta/(1-theta))exp(2..cap alpha..theta) together with the implied charge vs. surface excess relation: q = (1-theta)q/sub w/ + thetaQ were used to analyze the experimental data. Linear charge vs surface excess plots were obtained for the aliphatic compounds over the entire potential region studied; for benzyl alcohol, plots were linear only at anodic potentials. The slopes of these lines agreed with those predicted by the above equation, with Q = C/sub org/(V-V/sub n/), for cathodic potentials. At potentials anodic to the electrocapillary maximum, deviations between experimental and theoretical slopes appeared. In the model proposed, the double layer consists of two parts. The layer closest to the surface is restricted to water molecules and specifically adsorbed ions. The second layer contains organic molecules exclusively; any charge necessary to balance the surface charge is considered to be in a monolayer adjacent to the organic layer. From the slope of the charge vs surface excess plots, it is possible to calculate the charge on the covered portion of the surface and then calculate the amount of specific adsorption. The relative amounts of specific adsorption are in agreement with known strengths of adsorption of the anions of the electrolyte. Capacity curves were also calculated and were in good agreement with experimental curves.

  20. Mechanisms controlling the production and transport of methane, carbon dioxide, and dissolved solutes within a boreal peatland

    SciTech Connect

    Siegel, D.I.

    1992-04-09

    Peatlands are one of the most important terrestrial reservoirs in the global cycle for carbon, and are a major source for atmospheric methane. However, little is known about the dynamics of these carbon reservoirs or their feedback mechanisms with the pool of atmospheric CO{sub 2} during the Holocene. Specifically, it is unknown whether large peat basins are sources, sinks, or steady-state reservoirs for the global carbon cycle. In particular, the production and transport of methane, carbon dioxide, and dissolved organic carbon form the deeper portions of these peatlands is unknown. Our DOE research program is to conduct an integrated ecologic and hydrogeochemical study of the Glacial Lake Agassiz peatlands (northern Minnesota) to better understand the carbon dynamics in globally significant peat basins. Specifically, our study will provide local and regional data on (1), rates of carbon accumulation and loss and fluxes of methane in the peat profiles; (2) the physical and botanical factors controlling the production of methane and carbon dioxide in the wetland; and (3) the role of hydrogeologic processes in controlling the fluxes of gases and solutes through the peat. We intend to use computer simulation models, calibrated to field data, to scale-up from local to regional estimates of methane and carbon dioxide within the basin. How gases and dissolved organic carbon escapes form peatlands in unknown. It has been suggested that the concentrations of methane produced in the upper peat are sufficient to produce diffusion gradients towards the surface. Alternatively, gas may move through the peat profile by groundwater advection.

  1. Basic solutions to carbon/carbon oxidation: Science and technology. Final report, 15 April 1993--14 April 1998

    SciTech Connect

    Harrison, I.R.; Chung, T.; Pantano, C.; Radovic, L.; Thrower, P.

    1998-04-14

    The goal of this study was to gain a fundamental understanding of the role of boron in carbon oxidation. Boron-doped carbons were synthesized via CVD, ion implantation and high temperature doping are subsequently characterized. It was found that high temperature doped HOPG carbons were ideal for oxidation studies because their surface could be reproduced, their surface structures were determined and they were able to be characterized by XPS, AFM and SEM. The direct analysis of the chemical structures and atomic arrangements in boron- doped carbon or carbon surfaces by these techniques was critical in determining the effect of boron on carbon oxidation. XPS was utilized in this work to determine the local bonding environment of boron in carbon before an after oxidation. It was necessary to obtain an accurate calibration of the B1s binding energy scale which was accomplished by obtaining photoemission spectra of boron-doped carbons with known structures (local boron bonding environments), such as boron oxide, boron carbide, triphenylboroxine, tourmaline, boric acid, danburite and high temperature boron-doped graphite. All of the aforementioned standards contain boron in a unique bonding environment and thus their spectra formulated a complete conversion of B1s binding energies to boron chemical environments which has not been reported in the past. It was clearly established that a chemical shift for substitutional boron in graphite exists at 186.5 eV with a FWHM of 1.2. The chemical structures of the boron in the standards were related to the binding energy using a Pauling charge distribution model and a modification of the Sanderson electronegativity method. This approach was used to determine whether the B1s binding energy would change depending upon the specific location of boron in the graphite or graphite surface.

  2. Relationships among folate, alcohol consumption, gene variants in one-carbon metabolism and p16 INK4a methylation and expression in healthy breast tissues

    PubMed Central

    Llanos, Adana A.; Dumitrescu, Ramona G.; Brasky, Theodore M.; Liu, Zhenhua; Mason, Joel B.; Marian, Catalin; Makambi, Kepher H.; Spear, Scott L.; Kallakury, Bhaskar V.S.; Freudenheim, Jo L.; Shields, Peter G.

    2015-01-01

    p16 INK4a is a tumor suppressor gene, frequently hypermethylated in breast cancer; this epigenetic silencing of p16 INK4a occurs early in carcinogenesis. The risk factors and functional consequences of p16 INK4a methylation are unknown. Alcohol consumption, a breast cancer risk factor, impedes folate metabolism and may thereby alter gene methylation since folate plays a pivotal role in DNA methylation. In a cross-sectional study of 138 women with no history of breast cancer who underwent reduction mammoplasty, we studied breast cancer risk factors, plasma and breast folate concentrations, variation in one-carbon metabolism genes, p16 INK4a promoter methylation and P16 protein expression. Logistic regression was used to estimate multivariable-adjusted odds ratios (OR) and 95% confidence intervals (CI). p16 INK4a methylation was negatively correlated with P16 expression (r = −0.28; P = 0.002). Alcohol consumption was associated with lower breast folate (P = 0.03), higher p16 INK4a promoter methylation (P = 0.007) and less P16 expression (P = 0.002). Higher breast folate concentrations were associated with lower p16 INK4a promoter methylation (P = 0.06). Genetic variation in MTRR (rs1801394) and MTHFD1 (rs1950902) was associated with higher p16 INK4a promoter methylation (OR = 2.66, 95% CI: 1.11–6.42 and OR = 2.72, 95% CI: 1.12–6.66, respectively), whereas variation in TYMS (rs502396) was associated with less P16 protein expression (OR = 0.22, 95% CI: 0.05–0.99). Given that this is the first study to indicate that alcohol consumption, breast folate and variation in one-carbon metabolism genes are associated with p16 INK4a promoter methylation and P16 protein expression in healthy tissues; these findings require replication. PMID:25344837

  3. Carbon-Impurity Affected Depth Elemental Distribution in Solution-Processed Inorganic Thin Films for Solar Cell Application.

    PubMed

    Rehan, Shanza; Kim, Ka Young; Han, Jeonghyeob; Eo, Young-Joo; Gwak, Jihye; Ahn, Seung Kyu; Yun, Jae Ho; Yoon, KyungHoon; Cho, Ara; Ahn, SeJin

    2016-03-01

    A common feature of the inorganic thin films including Cu(In,Ga)(S,Se)2 fabricated by nonvacuum solution-based approaches is the doubled-layered structure, with a top dense inorganic film and a bottom carbon-containing residual layer. Although the latter has been considered to be the main efficiency limiting factor, (as a source of high series resistance), the exact influence of this layer is still not clear, and contradictory views are present. In this study, using a CISe as a model system, we report experimental evidence indicating that the carbon residual layer itself is electrically benign to the device performance. Conversely, carbon was found to play a significant role in determining the depth elemental distribution of final film, in which carbon selectively hinders the diffusion of Cu during selenization, resulting in significantly Cu-deficient top CISe layer while improving the film morphology. This carbon-affected compositional and morphological impact on the top CISe films is a determining factor for the device efficiency, which was supported by the finding that CISe solar cells processed from the precursor film containing intermediate amount of carbon demonstrated high efficiencies of up to 9.15% whereas the performances of the devices prepared from the precursor films with very high and very low carbon were notably poor. PMID:26817680

  4. Stress corrosion cracking of X-60 line pipe steel in a carbonate-bicarbonate solution

    SciTech Connect

    Pilkey, A.K.; Lambert, S.B.; Plumtree, A. . Dept. of Mechanical Engineering)

    1995-02-01

    An experimental system was developed to reproduce stress corrosion cracking (SCC) of API X-60 line pipe steels in highly alkaline (pH = 10) carbonate-bicarbonate (1 N sodium carbonate [Na[sub 2]CO[sub 3

  5. Multi-instrumental characterization of carbon nanotubes dispersed in aqueous solutions

    EPA Science Inventory

    Previous studies showed that the dispersion extent and physicochemical properties of carbon nanotubes are highly dependent upon the preparation methods (e.g., dispersion methods and dispersants). In the present work, multiwalled carbon nanotubes (MWNTs) are dispersed in aqueous s...

  6. Characteristics of nano-sized yttria powder synthesized by a polyvinyl alcohol solution route at low temperature.

    PubMed

    Lee, Sang-Jin; Jung, Choong-Hwan

    2012-01-01

    Nano-sized yttria (Y2O3) powders were successfully synthesized at a low temperature of 400 degrees C by a simple polymer solution route. PVA polymer, as an organic carrier, contributed to an atom-scale homogeneous precursor gel and it resulted in fully crystallized, nano-sized yttria powder with high specific surface area through the low temperature calcination. In this process, the content of PVA, calcination temperature and heating time affected the microstructure and crystallization behavior of the powders. The development of crystalline phase and the final particle size were strongly dependant on the oxidation reaction from the polymer burn-out step and the PVA content. In this paper, the PVA solution technique for the fabrication of nano-sized yttria powders is introduced. The effects of PVA content and holding time on the powder morphology and powder specific surface area are also studied. The characterization of the synthesized powders is examined by using XRD, DTA/TG, SEM, TEM and nitrogen gas adsorption. The yttria powder synthesized from the PVA content of 3:1 ratio and calcined at 400 degrees C had a crystallite size of about 20 nm or less with a high surface areas of 93.95-120.76 m2 g(-1).

  7. Kinetic analysis of the denaturation process by alcohols of sodium channels in squid giant axon.

    PubMed Central

    Kukita, F; Mitaku, S

    1993-01-01

    1. The effects of several aliphatic alcohols on sodium currents were examined in the intracellularly perfused squid giant axon when the same concentration of alcohol was applied on both sides of the membrane. 2. An irreversible suppression of sodium currents, accompanied by anaesthesia at high alcohol concentration, was examined in detail using four aliphatic alcohols, that is, ethanol, 1-propanol, 1-butanol and 1-pentanol. 3. This irreversible effect seemed to be attributable to the sequential denaturation of sodium channels, because the kinetics, the current-voltage relation and the sodium channel activation-voltage curve did not change after the sodium current decreased. 4. The time course of the remaining sodium conductance was measured as a function of the sum of the alcohol application time by repeating the process of applying and completely washing out alcohol. The remaining sodium conductance decayed as a function of time in a single exponential manner. This decay time constant depended strongly on the concentration of alcohol and could be assumed to be the denaturation time constant of the sodium channel. 5. The denaturation time constant decreased as the alcohol concentration increased. This time constant is proportional to the Nth power of the alcohol concentration. The N values are 4.3, 4.5, 5.8 and 7.6 for ethanol, 1-propanol, 1-butanol and 1-pentanol, respectively. This implies that alcohol molecules bind to a restricted number of specific sites in the sodium channel protein to cause the denaturation. 6. The concentration of alcohol which caused the same amount of denaturation is related to the exponential function of the carbon number of the alcohol. Considering the partition coefficient of alcohol between lipid and aqueous solution, the concentration of alcohol in the membrane which denatured half of the sodium channels in 2 h can be calculated to be 0.5 M for all alcohols. PMID:8246196

  8. Toward a zero-carbon energy policy in Europe: defining a viable solution

    SciTech Connect

    Jones, Christopher; Glachant, Jean-Michel

    2010-04-15

    The present pace of carbon emission is not sustainable. Human societies need to react and to change. A rational responsive policy to deliver the required carbon emission reduction can be delineated if the key objective parameters are identified and addressed. This article attempts to lay the groundwork for a viable carbon energy policy for Europe. (author)

  9. Activity and stability of immobilized carbonic anhydrase for promoting CO2 absorption into a carbonate solution for post-combustion CO2 capture.

    PubMed

    Zhang, Shihan; Zhang, Zhaohui; Lu, Yongqi; Rostam-Abadi, Massoud; Jones, Andrew

    2011-11-01

    An Integrated Vacuum Carbonate Absorption Process (IVCAP) currently under development could significantly reduce the energy consumed when capturing CO2 from the flue gases of coal-fired power plants. The biocatalyst carbonic anhydrase (CA) has been found to effectively promote the absorption of CO2 into the potassium carbonate solution that would be used in the IVCAP. Two CA enzymes were immobilized onto three selected support materials having different pore structures. The thermal stability of the immobilized CA enzymes was significantly greater than their free counterparts. For example, the immobilized enzymes retained at least 60% of their initial activities after 90 days at 50 °C compared to about 30% for their free counterparts under the same conditions. The immobilized CA also had significantly improved resistance to concentrations of sulfate (0.4 M), nitrate (0.05 M) and chloride (0.3 M) typically found in flue gas scrubbing liquids than their free counterparts.

  10. Activity and stability of immobilized carbonic anhydrase for promoting CO2 absorption into a carbonate solution for post-combustion CO2 capture

    USGS Publications Warehouse

    Zhang, S.; Zhang, Z.; Lu, Y.; Rostam-Abadi, M.; Jones, A.

    2011-01-01

    An Integrated Vacuum Carbonate Absorption Process (IVCAP) currently under development could significantly reduce the energy consumed when capturing CO2 from the flue gases of coal-fired power plants. The biocatalyst carbonic anhydrase (CA) has been found to effectively promote the absorption of CO2 into the potassium carbonate solution that would be used in the IVCAP. Two CA enzymes were immobilized onto three selected support materials having different pore structures. The thermal stability of the immobilized CA enzymes was significantly greater than their free counterparts. For example, the immobilized enzymes retained at least 60% of their initial activities after 90days at 50??C compared to about 30% for their free counterparts under the same conditions. The immobilized CA also had significantly improved resistance to concentrations of sulfate (0.4M), nitrate (0.05M) and chloride (0.3M) typically found in flue gas scrubbing liquids than their free counterparts. ?? 2011 Elsevier Ltd.

  11. The radiation induced chemistry of uranyl cation in aqueous carbonate –bicarbonate solutions as followed by NMR spectroscopy

    SciTech Connect

    McNamara, Bruce K.; Snow, Lanee A.; Soderquist, Chuck Z.; Sinkov, Sergei I.; Cho, Herman M.; Friese, Judah I.

    2006-05-01

    Alpha radiation induced formation of hydrogen peroxide in carbonate ?bicarbonate media was followed by 13C NMR using dissolved [233UO2(13CO3)3]4- as the alpha source (Dalpha= 12.1 Gy/hr). Between the pH region between 5.9 and 11.6 hydrogen peroxide causes a varied speciation of the uranyl carbonates that is a function of the uranium, carbonate and the hydrogen peroxide concentrations. It is shown that the speciation of the peroxy carbonates (or other species) formed in solution by titration with hydrogen peroxide are common to those formed by hydrogen peroxide generated by radiolysis. The radiolysis experiment was carried out above pH = 9.96 to minimize the loss of 13CO2 over a 2800 hr period. Radiolytic generation of hydrogen peroxide was followed by formation of a uranyl peroxy carbonate complex and complex formation accelerated for about 1200 hours. Complex formation was observed to terminate at a concentration between 1x10-4 and 5x10-4 M. It is assumed that either a steady state H2O2 production rate was established in solution or that some limiting feature of the experiment was responsible for slowing the yield of product.

  12. conversion electron Mössbauer study of low carbon steel polarized in aqueous sulfate solution containing sulfite in low concentration

    NASA Astrophysics Data System (ADS)

    Vértes, Cs.; Lakatos-Varsányi, M.; Vértes, A.; Kuzmann, E.; Meisel, W.; Gütlich, P.

    1992-04-01

    The passivation of low carbon steel was studied in aqueous solution of 0.5 M Na2SO4+0.001 M NaHSO3 at pH=3.5 and 6.5. The found major components at pH-3.5 were: γ-FeOOH and Fe3C, and also FeSO4.H2O could be identified on the surface of the low carbon steel as a minor component. At pH-6.5, the passive film contained only amorphous iron(III)-oxide or oxyhydroxide.

  13. Surface modification of activated carbon for enhanced adsorption of perfluoroalkyl acids from aqueous solutions.

    PubMed

    Zhi, Yue; Liu, Jinxia

    2016-02-01

    The objective of the research was to examine the effect of increasing carbon surface basicity on uptake of perfluorooctane sulfonic (PFOS) and carboxylic acids (PFOA) by activated carbon. Granular activated carbons made from coal, coconut shell, wood, and phenolic-polymer-based activated carbon fibers were modified through high-temperature and ammonia gas treatments to facilitate systematical evaluation of the impact of basicity of different origins. Comparison of adsorption isotherms and adsorption distribution coefficients showed that the ammonia gas treatment was more effective than the high-temperature treatment in enhancing surface basicity. The resultant higher point of zero charges and total basicity (measured by total HCl uptake) correlated with improved adsorption affinity for PFOS and PFOA. The effectiveness of surface modification to enhance adsorption varied with carbon raw material. Wood-based carbons and activated carbon fibers showed enhancement by one to three orders of magnitudes while other materials could experience reduction in adsorption towards either PFOS or PFOA.

  14. Surface modification of activated carbon for enhanced adsorption of perfluoroalkyl acids from aqueous solutions.

    PubMed

    Zhi, Yue; Liu, Jinxia

    2016-02-01

    The objective of the research was to examine the effect of increasing carbon surface basicity on uptake of perfluorooctane sulfonic (PFOS) and carboxylic acids (PFOA) by activated carbon. Granular activated carbons made from coal, coconut shell, wood, and phenolic-polymer-based activated carbon fibers were modified through high-temperature and ammonia gas treatments to facilitate systematical evaluation of the impact of basicity of different origins. Comparison of adsorption isotherms and adsorption distribution coefficients showed that the ammonia gas treatment was more effective than the high-temperature treatment in enhancing surface basicity. The resultant higher point of zero charges and total basicity (measured by total HCl uptake) correlated with improved adsorption affinity for PFOS and PFOA. The effectiveness of surface modification to enhance adsorption varied with carbon raw material. Wood-based carbons and activated carbon fibers showed enhancement by one to three orders of magnitudes while other materials could experience reduction in adsorption towards either PFOS or PFOA. PMID:26469934

  15. Preparation and structure analysis of carbon/carbon composite made from phenolic resin impregnation into exfoliated graphite

    NASA Astrophysics Data System (ADS)

    Chen, X.; Zheng, Y. P.; Kang, F.; Shen, W. C.

    2006-05-01

    Exfoliated graphite-based carbon/carbon composites were prepared using sequence processes of phenolic resin alcohol solution impregnation, carbonization and carbon dioxide (or steam) activation. The textural/structural characteristics of the composites were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), nitrogen adsorption and mercury porosimetry. The results indicated that the composites were composed of graphite and amorphous carbon. On the surface, the worm-like particles were covered by pyrolytic carbon, which also penetrated into parts of the interior pores of the particles. Macropores still remained in the composite, whereas micropores which were formed by the activation of pyrolytic carbon contributed to most of the pore volume.

  16. Prevention of Alcohol Abuse among Black Americans.

    ERIC Educational Resources Information Center

    Journal of Alcohol and Drug Education, 1992

    1992-01-01

    Originally published in "Alcohol Health and Research World," this article is report of interview with Thomas D. Watts and Roosevelt Wright, Jr., conducted to explore solutions to complex problem of prevention of alcoholism among African Americans. Introduces readers to work of two experts in area of alcohol abuse and alcoholism among African…

  17. Adsorption of chlorophenols from aqueous solutions by pristine and surface functionalized single-walled carbon nanotubes.

    PubMed

    Ding, Han; Li, Xin; Wang, Jun; Zhang, Xiaojian; Chen, Chao

    2016-05-01

    The adsorption of six kinds of chlorophenols on pristine, hydroxylated and carboxylated single-walled carbon nanotubes (SWCNTs) has been investigated. Pseudo-first order and pseudo-second order models were used to describe the kinetic data. All adsorption isotherms were well fitted with Langmuir, Freundlich and Polanyi-Manes models, due to surface adsorption dominating the adsorption process. The close linear relationship between logKow and logKd suggested that hydrophobicity played an important role in the adsorption. The SWCNTs' adsorption capacity for chlorophenols was weakened by addition of oxygen-containing functional groups on the surface, due to the loss of specific surface area, the increase of hydrophilicity and the reduction of π-π interaction. The best adsorption capacity of pristine SWCNTs, SWCNT-OH and SWCNT-COOH for six chlorophenols varied from 19 to 84mg/g, from 19 to 65mg/g and from 17 to 65mg/g, respectively. The effect of pH on the adsorption of 2,6-dichlorophenol (2,6-DCP), was also studied. When pH is over the pKa of 2,6-dichlorophenol (2,6-DCP), its removal dropped sharply. When ionic strength increased (NaCl or KCl concentration from 0 to 0.02mmol/L), the adsorption capacity of 2,6-DCP on pristine SWCNTs decreased slightly. The comparison of chlorophenols adsorption by SWCNTs, MWCNTs and PAC was made, indicating that the adsorption rate of CNTs was much faster than that of PAC. The results provide useful information about the feasibility of SWCNTs as an adsorbent to remove chlorophenols from aqueous solutions.

  18. Synthesis and utilization of a novel carbon nanotubes supported nanocables for the adsorption of dyes from aqueous solutions

    NASA Astrophysics Data System (ADS)

    Liu, Wei; Jiang, Xinyu; Chen, Xiaoqing

    2015-09-01

    Using multiwalled carbon nanotubes(MWCNTs) as mechanical support and glucose as carbon resource, a hydrothermal carbonization route was designed for the synthesis of MWCNTs@carbon nanocables with tunable diameter and length. MWCNTs are firstly used as templates for the formation of carbon-rich composite nanocables, and the diameter of the nanocables could be tailored through adjusting the hydrothermal time or the ratio of MWCNTs and glucose. Owing to abundant superficial oxygen-containing functional groups, porous surface and remarkable reactivity, the as-synthesized nanocables are capable of efficiently adsorbing cationic dye methylene blue (MB) and crystal violet (CV). Furthermore, the optimum adsorption conditions, kinetics, adsorption isotherms and adsorption thermodynamics of dyes were studied systematically. Additionally, the maximum adsorption capacities calculated from data analysis (298.5 mg/g for MB and 228.3 mg/g for CV) are significant higher than those of raw MWCNTs and some other adsorbents reported previously, which provides strong evidence for using MWCNTs@carbon nanocables as adsorbent to remove dyes from aqueous solutions.

  19. Advances in preparation of modified activated carbon and its applications in the removal of chromium (VI) from aqueous solutions

    NASA Astrophysics Data System (ADS)

    Deng, Z. L.; Liang, M. N.; Li, H. H.; Zhu, Z. J.

    2016-08-01

    The wastewater in which Cr(VI) is not fully treated has drawn environment researchers’ attention increasingly, due to its environmental pollution and harms to human health. Thus a high efficiency of modified activated carbon (MAC) to remove Cr(VI) has become one of the hot topics among environmental material research. This paper introduces the modification methods from the physical structure features and chemical properties of the activated carbon (AC) surface. At the same time, it briefly analyses the chemical characteristics of Cr(VI) in aqueous solutions, and on the basis of the aforementioned introduces the modification methods of the surface chemical characteristics of AC, such as: oxidation modification, reduction modification, loaded metal modification, and microwave modification. Combining studies on removing Cr(VI) from aqueous solutions by MAC in recent years, this paper anticipates the new trends of preparing MAC and the points in absorption research, offering some suggestions for future studies.

  20. Study of caffeine as corrosion inhibitors of carbon steel in chloride solution containing hydrogen sulfide using electrochemical impedance spectroscopy (EIS)

    NASA Astrophysics Data System (ADS)

    Solehudin, Agus; Berman, Ega Taqwali; Nurdin, Isdiriayani

    2015-09-01

    The corrosion behaviour of steel surface in the absence and presence of caffeine in 3.5% NaCl solution containing dissolved H2S gas is studied using electrochemical impedance spectroscopy (EIS). The experimental results of carbon steel corrosion in 3.5% NaCl solution containing 500 mg/l H2S at different caffeine concentrations showed that corrosion rate of carbon steel decreases with increasing of caffeine concentrations from 0 to 0,1 mmol/l. Whereas, the corrosion rate increase with increasing of caffeine concentrations from 1 to 10 mmol/l. It is clear that no inhibition efficiency increases with increasing inhibitor concentration. The optimum value of inhibition efficiency was 90% at a caffeine concentration of 0.1 mmol/l. This suggests that caffeine's performance as a corrosion inhibitor is more effective at a concentration of 0.1 mmol/l.

  1. Myths about drinking alcohol

    MedlinePlus

    ... to. I spend a lot of time getting alcohol, drinking alcohol, or recovering from the effects of alcohol. ... Institute on Alcohol Abuse and Alcoholism. Overview of Alcohol Consumption. www.niaaa.nih.gov/alcohol-health/overview-alcohol- ...

  2. Kinetic characteristics of the synthesis of multiwall carbon nanotubes by aerosol pyrolysis of a ferrocene solution in benzene

    NASA Astrophysics Data System (ADS)

    Cherkasov, N. B.; Savilov, S. B.; Pryakhin, A. N.; Ivanov, A. S.; Lunin, V. V.

    2012-03-01

    Approximating the experimental data on the mass distribution of multiwall carbon nanotubes (MCNT) along a reactor, a three-step kinetic model of their synthesis in the aerosol pyrolysis of a ferrocene solution in benzene is proposed. The values of effective rate constants upon the introduction of a catalyst in situ for the reactions that are the basis for synthesizing MCNT via the pyrolysis of hydrocarbons are obtained for the first time.

  3. Coagulation of chitin and cellulose from 1-ethyl-3-methylimidazolium acetate ionic-liquid solutions using carbon dioxide.

    PubMed

    Barber, Patrick S; Griggs, Chris S; Gurau, Gabriela; Liu, Zhen; Li, Shan; Li, Zengxi; Lu, Xingmei; Zhang, Suojiang; Rogers, Robin D

    2013-11-18

    Chemisorption of carbon dioxide by 1-ethyl-3-methylimidazolium acetate ([C2 mim][OAc]) provides a route to coagulate chitin and cellulose from [C2 mim][OAc] solutions without the use of high-boiling antisolvents (e.g., water or ethanol). The use of CO2 chemisorption as an alternative coagulating process has the potential to provide an economical and energy-efficient method for recycling the ionic liquid. PMID:24115399

  4. The impact of carbon and oxygen in alpha-titanium: ab initio study of solution enthalpies and grain boundary segregation.

    PubMed

    Aksyonov, D A; Hickel, T; Neugebauer, J; Lipnitskii, A G

    2016-09-28

    The solution, grain boundary (GB) segregation, and co-segregation of carbon and oxygen atoms in α-titanium are studied using density functional theory. For five titanium tilt boundaries, including T1, T2, and C1 twin systems, we determine the GB structure, as well as GB energy and excess volume. The segregation energies and volumes of carbon and oxygen are calculated for 23 inequivalent interstitial voids, while for co-segregation 75 configurations are considered. It is obtained that depending on the type of the segregation void both a positive and a negative segregation process is possible. The physical reasons of segregation are explained in terms of the analysis of the void atomic geometry, excess volume and features of the electronic structure at the Fermi level. Although carbon and oxygen show qualitatively similar properties in α-Ti, several distinctions are observed for their segregation behavior and mutual interactions. PMID:27460043

  5. The impact of carbon and oxygen in alpha-titanium: ab initio study of solution enthalpies and grain boundary segregation

    NASA Astrophysics Data System (ADS)

    Aksyonov, D. A.; Hickel, T.; Neugebauer, J.; Lipnitskii, A. G.

    2016-09-01

    The solution, grain boundary (GB) segregation, and co-segregation of carbon and oxygen atoms in α-titanium are studied using density functional theory. For five titanium tilt boundaries, including T1, T2, and C1 twin systems, we determine the GB structure, as well as GB energy and excess volume. The segregation energies and volumes of carbon and oxygen are calculated for 23 inequivalent interstitial voids, while for co-segregation 75 configurations are considered. It is obtained that depending on the type of the segregation void both a positive and a negative segregation process is possible. The physical reasons of segregation are explained in terms of the analysis of the void atomic geometry, excess volume and features of the electronic structure at the Fermi level. Although carbon and oxygen show qualitatively similar properties in α-Ti, several distinctions are observed for their segregation behavior and mutual interactions.

  6. Synthesis and utilization of a novel carbon nanotubes supported nanocables for the adsorption of dyes from aqueous solutions

    SciTech Connect

    Liu, Wei; Jiang, Xinyu; Chen, Xiaoqing

    2015-09-15

    Using multiwalled carbon nanotubes(MWCNTs) as mechanical support and glucose as carbon resource, a hydrothermal carbonization route was designed for the synthesis of MWCNTs@carbon nanocables with tunable diameter and length. MWCNTs are firstly used as templates for the formation of carbon-rich composite nanocables, and the diameter of the nanocables could be tailored through adjusting the hydrothermal time or the ratio of MWCNTs and glucose. Owing to abundant superficial oxygen-containing functional groups, porous surface and remarkable reactivity, the as-synthesized nanocables are capable of efficiently adsorbing cationic dye methylene blue (MB) and crystal violet (CV). Furthermore, the optimum adsorption conditions, kinetics, adsorption isotherms and adsorption thermodynamics of dyes were studied systematically. Additionally, the maximum adsorption capacities calculated from data analysis (298.5 mg/g for MB and 228.3 mg/g for CV) are significant higher than those of raw MWCNTs and some other adsorbents reported previously, which provides strong evidence for using MWCNTs@carbon nanocables as adsorbent to remove dyes from aqueous solutions. - Graphical abstract: MWCNTs@carbon nanocables has been successfully fabricated by a hydrothermal carbonization method. The as-synthesized novel samples were used as adsorbents and exhibited high adsorption capacity on MB and CV. - Highlights: • A simple, cost-effective and “green” method for the synthesis of the material. • The diameter and length of the material are relatively easy to control. • The surface has large oxygen-containing groups and preferable chemical reactivity. • Compared with raw MWCNTs and some other adsorbents, the adsorption capacity is much high.

  7. The adsorption and inhibition effect of calcium lignosulfonate on Q235 carbon steel in simulated concrete pore solution

    NASA Astrophysics Data System (ADS)

    Wang, Yishan; Zuo, Yu; Zhao, Xuhui; Zha, Shanshan

    2016-08-01

    The corrosion inhibition of calcium lignosulfonate (CLS) for Q235 carbon steel in saturated Ca(OH)2 + 0.1 mol/L NaCl solution was studied by means of weight loss, polarization, fluorescence microscopy (FM), scanning electron microscopy/energy dispersive spectrometry (SEM/EDS), microscopic infrared spectral imaging (M-IR) and X-ray photoelectron spectroscopy (XPS). For the steel in simulated concrete pore solution (pH 12.6), an increase of Eb value and a decrease of icorr value occurred with different concentrations of CLS. The optimal content of CLS was 0.001 mol/L at which the inhibition rate was 98.86% and the Eb value increased to 719 mV after 10 h of immersion. In mortar solution and in reinforced concrete environment, CLS also showed good inhibition for steel. The preferential adsorption of CLS around pits was detected by M-IR. The result illustrates that at the early stage the adsorption of CLS was heterogeneous and CLS may have a competitive adsorption with chloride ions at the active sites, which would be beneficial for decreasing the susceptibility of pitting corrosion. After the pre-filming time, an intact adsorption CLS film formed on carbon steel surface. The adsorption between CLS and calcium presented as Casbnd Osbnd S bonds. The adsorption of CLS on carbon steel surface occurred probably by both physisorption and chemisorption.

  8. Utilization of activated carbon produced from fruit juice industry solid waste for the adsorption of Yellow 18 from aqueous solutions.

    PubMed

    Angin, Dilek

    2014-09-01

    The use of activated carbon obtained from sour cherry (Prunus cerasus L.) stones for the removal of a basic textile dye, which is Yellow 18, from aqueous solutions at different contact times, pH values and solution temperatures was investigated. The surface area and micropore volume of chemically modified activated carbon were 1704 m(2) g(-1) and 0.984 cm(3) g(-1), respectively. The experimental data indicated that the adsorption isotherms were well described by the Langmuir equilibrium isotherm equation and the calculated adsorption capacity was 75.76 mg g(-1) at 318 K. The adsorption kinetic of Yellow 18 obeys the pseudo-second-order kinetic model. The thermodynamic parameters were calculated to estimate the nature of adsorption. The activation energy of the system was calculated as 0.71-2.36 kJ/mol. According to these results, prepared activated carbon could be used as a low-cost adsorbent to compare with the commercial activated carbon for the removal of Yellow 18 from wastewater. PMID:24656549

  9. Influence of ultrasonic frequency on Swan band sonoluminescence and sonochemical activity in aqueous tert-butyl alcohol solutions.

    PubMed

    Pflieger, Rachel; Ndiaye, Abdoul Aziz; Chave, Tony; Nikitenko, Sergey I

    2015-01-01

    The multibubble sonoluminescence (MBSL) spectra of t-BuOH aqueous solutions submitted to power ultrasound at 20, 204, 362, and 613 kHz show emissions for the Δυ = -1 to Δυ = +2 vibrational sequences of C2* Swan system (d(3)Πg → a(3)Πu). The Δυ=+2 emission overlaps with the CH(A-X) emission band. The maximal Swan band emission is observed when the MBSL of water itself is almost completely quenched. In general, MBSL is more intense at high-frequency compared to 20 kHz ultrasound. However, in the presence of Xe, the MBSL of C2* at 20 kHz is so bright that it can be seen by the unaided eye as a blue glow in the close vicinity of the ultrasonic tip. The intensity of the C2* band emission exhibits a maximum vs t-BuOH concentration: 0.1-0.2 M at 20 kHz and (1-8) × 10(-3) M at high-frequency ultrasound. Such a huge difference is attributed to a much smaller bubble size at high ultrasonic frequency or, in other words, to a much higher bubble surface/volume ratio providing more efficient saturation of the bubble interior with t-BuOH vapors and to the fact that high frequency bubbles remain active for many more cycles than 20 kHz ones, thus accumulating more hydrocarbon decomposition products. Simulation of the emission spectra using Specair software demonstrated the absence of thermal equilibrium for C2* radicals (Tv > Tr), where Tv and Tr are the vibrational and the rotational temperature, respectively. In Ar, Tv decreases with increasing t-BuOH concentration reaching a steady value in the concentration domain that corresponds to C2* emission maximum intensity. In the presence of Xe an extremely high Tv is obtained, which is explained by the relatively low ionization potential of Xe providing a higher electron temperature of nonequilibrium plasma generated during bubble collapse. Analysis of the gaseous products of t-BuOH sonolysis reveals a significant sonochemical activity even at high t-BuOH concentration when MBSL is totally quenched, indicating that drastic

  10. Alkali promoted molybdenum (IV) sulfide based catalysts, development and characterization for alcohol synthesis from carbon monoxide and hydrogen

    NASA Astrophysics Data System (ADS)

    Molina, Belinda Delilah

    For more than a century transition metal sulfides (TMS) have been the anchor of hydro-processing fuels and upgrading bitumen and coal in refineries worldwide. As oil supplies dwindle and environmental laws become more stringent, there is a greater need for cleaner alternative fuels and/or synthetic fuels. The depletion of oil reserves and a rapidly increasing energy demand worldwide, together with the interest to reduce dependence on foreign oil makes alcohol production for fuels and chemicals via the Fischer Tropsch synthesis (FTS) very attractive. The original Fischer-Tropsch (FT) reaction is the heart of all gas-to-liquid technologies; it creates higher alcohols and hydrocarbons from CO/H2 using a metal catalyst. This research focuses on the development of alkali promoted MoS2-based catalysts to investigate an optimal synthesis for their assistance in the production of long chain alcohols (via FTS) for their use as synthetic transportation liquid fuels. Properties of catalytic material are strongly affected by every step of the preparation together with the quality of the raw materials. The choice of a laboratory method for preparing a given catalyst depends on the physical and chemical characteristics desired in the final composition. Characterization methods of K0.3/Cs0.3-MoS2 and K0.3 /Cs0.3-Co0.5MoS2 catalysts have been carried out through Scanning Electron Microscopy (SEM), BET porosity and surface analysis, Transmission Electron Microscopy (TEM) and X-Ray Diffraction (XRD). Various characterization methods have been deployed to correlate FTS products versus crystal and morphological properties of these heterogeneous catalysts. A lab scale gas to liquid system has been developed to evaluate its efficiency in testing FT catalysts for their production of alcohols.

  11. A SEARCH FOR INTERSTELLAR CARBON-CHAIN ALCOHOL HC{sub 4}OH IN STAR-FORMING REGION L1527 AND DARK CLOUD TMC-1

    SciTech Connect

    Araki, Mitsunori; Yamabe, Hiromichi; Koshikawa, Naohiro; Tsukiyama, Koichi; Takano, Shuro; Nakane, Aya; Okabayashi, Toshiaki; Kunimatsu, Arisa; Kuze, Nobuhiko

    2012-01-10

    We report a sensitive search for the rotational transitions of the carbon-chain alcohol HC{sub 4}OH in the frequency range 21.2-46.7 GHz in the star-forming region L1527 and the dark cloud TMC-1. The motivation was laboratory detection of HC{sub 4}OH by microwave spectroscopy. Despite achieving rms noise levels of several millikelvin in the antenna temperature using the 45 m telescope at Nobeyama Radio Observatory, the detection was not successful, leading to 3{sigma} upper limits corresponding to the column densities of 2.0 Multiplication-Sign 10{sup 12} and 5.6 Multiplication-Sign 10{sup 12} cm{sup -2} in L1527 and TMC-1, respectively. These upper limits indicate that [HC{sub 4}OH]/[HC{sub 5}N] ratios are less than 0.3 and 0.1 in L1527 and TMC-1, respectively, where HC{sub 5}N is an HC{sub 4}-chain cyanide and HC{sub 4}OH is a hydroxide. These ratios suggest that the cyano carbon-chain molecule dominates the hydroxyl carbon-chain molecule in L1527 and TMC-1. This is contrary to the case of saturated compounds in hot cores, e.g., CH{sub 3}OH and CH{sub 3}CN, and can be a chemical feature of carbon-chain molecules in L1527 and TMC-1. In addition, the column densities of the 'unsubstituted' carbon-chain molecule C{sub 4}H and the sulfur-bearing molecules SO and HCS{sup +} were determined from detected lines in L1527.

  12. Multi-walled carbon nanotubes and poly(lactic acid) nanocomposite fibrous membranes prepared by solution blow spinning.

    PubMed

    Oliveira, Juliano E; Zucolotto, Valtencir; Mattoso, Luiz H C; Medeiros, Eliton S

    2012-03-01

    Nanocomposite fibers based on multi-walled carbon nanotubes (MWCNT) and poly(lactic acid) (PLA) were prepared by solution blow spinning (SBS). Fiber morphology was characterized by scanning electron microscopy (SEM) and optical microscopy (OM). Electrical, thermal, surface and crystalline properties of the spun fibers were evaluated, respectively, by conductivity measurements (4-point probe), thermogravimetric analyses (TGA), differential scanning calorimetry (DSC), contact angle and X-ray diffraction (XRD). OM analysis of the spun mats showed a poor dispersion of MWCNT in the matrix, however dispersion in solution was increased during spinning where droplets of PLA in solution loaded with MWCNT were pulled by the pressure drop at the nozzle, producing PLA fibers filled with MWCNT. Good electrical conductivity and hydrophobicity can be achieved at low carbon nanotube contents. When only 1 wt% MWCNT was added to low-crystalline PLA, surface conductivity of the composites increased from 5 x 10(-8) to 0.46 S/cm. Addition of MWCNT can slightly influence the degree of crystallinity of PLA fibers as studied by XRD and DSC. Thermogravimetric analyses showed that MWCNT loading can decrease the onset degradation temperature of the composites which was attributed to the catalytic effect of metallic residues in MWCNT. Moreover, it was demonstrated that hydrophilicity slightly increased with an increase in MWCNT content. These results show that solution blow spinning can also be used to produce nanocomposite fibers with many potential applications such as in sensors and biosensors. PMID:22755116

  13. Chemical and structural evaluation of activated carbon prepared from jute sticks for Brilliant Green dye removal from aqueous solution.

    PubMed

    Asadullah, Mohammad; Asaduzzaman, Mohammad; Kabir, Mohammad Shajahan; Mostofa, Mohammad Golam; Miyazawa, Tomohisa

    2010-02-15

    Activated carbons have been prepared from jute sticks by chemical activation using ZnCl(2) and physical activation using steam for the removal of Brilliant Green dye from aqueous solution. The activated carbons and charcoal prepared from jute sticks were characterized by evaluating the surface chemistry, structural features and surface morphology. The maximum BET surface area was obtained to be 2304 m(2)/g for chemical activated carbon (ACC) while it is 730 and 80 m(2)/g for steam activated carbon (ACS) and charcoal, respectively. The FT-IR spectra exhibited that the pyrolysis and steam activation of jute sticks resulted in the release of aliphatic and O-containing functional groups by thermal effect. However, the release of functional groups is the effect of chemical reaction in the ZnCl(2) activation process. A honeycomb-type carbon structure in ACC was formed as observed on SEM images. Although charcoal and ACC were prepared at 500 degrees C the ACC exhibited much lower Raman sensitivity due to the formation of condensed aromatic ring systems. Due to high surface area and high porous structure with abundance of functional groups, the ACC adsorbed dye molecules with much higher efficiency than those of ACS and charcoal.

  14. Evaluation of carbons derived from Gingelly oil cake for the removal of lead(II) from aqueous solutions.

    PubMed

    Nagashanmugam, K B; Srinivasan, K

    2010-10-01

    The adsorption of lead(II) onto activated carbons prepared from Gingelly Oil Cake (GOC) by using thermal, sulphuric and zinc chloride activations was investigated. The effects of experimental parameters such as pH, initial concentration, contact time and adsorbents dosage on the lead(II) removal were studied. The data were fitted with Langmuir, Freundlich and Temkin models to describe the equilibrium isotherms. The kinetic data fitted well with Lagergren pseudo first order and pseudo second order models. The maximum adsorption capacity for lead(II) on adsorbents calculated from Langmuir isotherm was found to be 105.26 mg/g and 114.94 mg/g for thermally activated and sulphuric acid activated carbons respectively. R2 values show that Langmuir model fits best to sulphuric acid activated carbon and Freundlich model fits best to thermally activated and zinc chloride activated carbons. The kinetic rates were best fitted to pseudo second order model. FT-IR analysis was used to obtain information on the nature of possible interaction between adsorbents and metal ions. SEM images confirmed the adsorption of lead(II) onto GOC adsorbents through morphological observations. Thermodynamic study showed the feasibility of process and spontaneous nature of the adsorption. The adsorbents were also tested for the removal of lead(II) from lead battery synthetic wastewater. The results indicate that carbons derived from GOC could be used to effectively adsorb lead(II) from aqueous solutions and wastewaters.

  15. Nanosized CuO and ZnO Catalyst Supported on Honeycomb-Typed Monolith for Hydrogenation of Carbon Dioxide to Methyl Alcohol.

    PubMed

    Park, Chul-Min; Ahn, Won-Ju; Jo, Woong-Kyu; Song, Jin-Hun; Oh, Chang-Yeop; Jeong, Young-Shin; Chung, Min-Chul; Park, Kwon-Pil; Kim, Ki-Joong; Jeong, Woon-Jo; Sohn, Bo-Kyun; Jung, Sang-Chul; Lee, Do-Jin; Ahn, Byeong-Kwon; Ahn, Ho-Geun

    2015-01-01

    The greenhouse effect of carbon dioxide (CO2) has been recognized as one of the most serious problems in the world. Conversion of CO2 to methyl alcohol (CH3OH) was studied using catalytic chemical methods. Honeycomb-typed monolith used as catalyst support was 400 cell/inch2. Pretreatment of the monolith surface was carried out by thermal treatment and acid treatment. Monolith-supported nanosized CuO-ZnO catalysts were prepared by wash-coat method. The prepared catalysts were characterized by using SEM, TEM, and XRD. The catalytic activity for CO2 hydrogenation to CH3OH was investigated using a flow-type reactor with varying reaction temperature, reaction pressure and contact time. Conversion of CO2 was increased with increasing reaction temperature, but selectivity to CH3OH was decreased. Optimum reaction temperature was about 250 degrees C under 20 atm. Because of the reverse water gas shift reaction.

  16. 2, 4 dichlorophenol (2, 4-DCP) sorption from aqueous solution using granular activated carbon and polymeric adsorbents and studies on effect of temperature on activated carbon adsorption.

    PubMed

    Ghatbandhe, A S; Yenkie, M K N

    2008-04-01

    Adsorption equilibrium, kinetics and thermodynamics of 2,4-dichlorophenol (2,4-DCP), one of the most commonly used chlorophenol, onto bituminous coal based Filtrasorb-400 grade granular activated carbon, were studied in aqueous solution in a batch system with respect to temperature. Uptake capacity of activated carbon found to increase with temperature. Langmuir isotherm models were applied to experimental equilibrium data of 2, 4-DCP adsorption and competitive studies with respect to XAD resin were carried out. Equilibrium data fitted very well to the Langmuir equilibrium model. Adsorbent monolayer capacity 'Q0, Langmuir constant 'b' and adsorption rate constant 'k(a)' were evaluated at different temperatures for activated carbon adsorption. This data was then used to calculate the energy of activation of adsorption and also the thermodynamic parameters, namely the free energy of adsorption, deltaG0, enthalpy of adsorption, deltaH0 and the entropy of adsorption deltaS0. The obtained results showed that the monolayer capacity increases with the increase in temperatures. The obtained values of thermodynamic parameters showed that adsorption of 2,4 DCP is an endothermic process. Synthetic resin was not found efficient to adsorb 2,4 DCP compared to activated carbon. The order of adsorption efficiencies of three resins used in the study found as XAD7HP > XAD4 > XAD1180.

  17. Alcohol and Alcoholism.

    ERIC Educational Resources Information Center

    National Inst. of Mental Health (DHEW), Chevy Chase, MD. National Clearinghouse for Mental Health Information.

    This concise survey presents some of the highlights of modern research on drinking and alcoholism, as based on technical articles published in the scientific literature and the views expressed by leading authorities in the field. Contents include discussions about: (1) the nature and scope of the problem; (2) the chemical composition of alcoholic…

  18. Adsorption of pharmaceutical compounds and an endocrine disruptor from aqueous solutions by carbon materials.

    PubMed

    Sotelo, José L; Rodríguez, Araceli R; Mateos, María M; Hernández, Sergio D; Torrellas, Silvia A; Rodríguez, Juan G

    2012-01-01

    Adsorption has been used to study the removal of atenolol, caffeine, diclofenac and isoproturon, pharmaceutical compounds as emerging contaminants and an endocrine disruptor from ultrapure water and a municipal wastewater treatment plant effluent with three carbonaceous materials: activated carbon, multiwalled carbon nanotubes and carbon nanofibers. The adsorption capacities were studied in the temperature range of 25-65°C and pH range from 3 to 9. Several model isotherms were used to model the adsorption equilibrium data. Also, the competitive adsorption was evaluated.

  19. Low carbon flower buildup, low smoke, and efficient diesel operation with vegetable oils by conversion to mono-esters and blending with diesel oil or alcohols

    SciTech Connect

    Nobukazu, T.; Itow, K.

    1984-01-01

    The purpose of this investigation is to evaluate the feasibility of rapeseed oil and palm oil for diesel fuel substitution in a naturally aspirated DI Diesel engine is evaluated. Means to reduce the carbon deposit buildup in vegetable oil combustion is found. In the experiments, the engine performance, exhaust gas emissions, and carbon deposits are measured for a number of fuels: rapeseed oil, palm oil, methylester of rapeseed oil, and these fuels blended with ethanol or diesel fuel with different fuel temperatures. Both of the vegetable oil fuels generate an acceptable engine performance and exhaust gas emission levels for short term operation, but they cause carbon deposit buildups and sticking of piston rings after extended operation. Practical solutions to overcome the problems are: increasing the fuel temperature to over 200/sup 0/C, blending 25 vol % diesel fuel in the vegetable oil, blending 20 vol % ethanol in the fuel, or converting the vegetable oils into methylesters.

  20. Adsorption of tetracycline on single-walled and multi-walled carbon nanotubes as affected by aqueous solution chemistry.

    PubMed

    Ji, Liangliang; Chen, Wei; Bi, Jun; Zheng, Shourong; Xu, Zhaoyi; Zhu, Dongqiang; Alvarez, Pedro J

    2010-12-01

    Carbon nanotubes have shown great potential as effective adsorbents for hydrophobic organic contaminants in water treatment. The present study investigated the influence of aqueous solution chemistry on the adsorption of tetracycline to carbon nanotubes. Specifically, the effects of ionic strength (NaCl and CaCl(2) ) and presence of Cu(2+) ion (7.5 mg/L) or dissolved soil or coal humic acids (50 mg/L) on adsorption of tetracycline to single-walled carbon nanotubes (SWNT), multi-walled carbon nanotubes (MWNT), and nonporous pure graphite as a model of the graphite surface were systematically estimated. The presence of humic acids suppressed tetracycline adsorption on graphite and MWNT prominently, with stronger effects observed on graphite, but only slightly affected tetracycline adsorption on SWNT. The relatively large humic acid components could not readily access the small interstitial spaces of SWNT and thus were less competitive with tetracycline adsorption. The presence of Cu(2+) ion increased tetracycline adsorption to both SWNT and MWNT through the mechanism of cation bridging, with much larger effects observed on MWNT. This was probably because when compared with the Cu(2+) ions complexed on the surface of SWNT, those on the surface of MWNT having larger mesoporous interstices were more accessible to the relatively bulky tetracycline molecule. Increasing the ionic strength from 10 mM to 100 mM decreased tetracycline adsorption on both SWNT and MWNT, which was attributed to electronic shielding of the negatively charged surface sites. These results show that aqueous solution chemistry is important to tetracycline adsorption on carbon nanotubes.

  1. Effect of acetate and carbonate buffers on the photolysis of riboflavin in aqueous solution: a kinetic study.

    PubMed

    Ahmad, Iqbal; Anwar, Zubair; Iqbal, Kefi; Ali, Syed Abid; Mirza, Tania; Khurshid, Adeela; Khurshid, Aqeela; Arsalan, Adeel

    2014-06-01

    The photolysis of riboflavin (RF) in the presence of acetate buffer (pH 3.8-5.6) and carbonate buffer (pH 9.2-10.8) has been studied using a multicomponent spectrophotometric method for the simultaneous assay of RF and its photoproducts. Acetate and carbonate buffers have been found to catalyze the photolysis reaction of RF. The apparent first-order rate constants for the acetate-catalyzed reaction range from 0.20 to 2.86 × 10(-4) s(-1) and for the carbonate-catalyzed reaction from 3.33 to 15.89 × 10(-4) s(-1). The second-order rate constants for the interaction of RF with the acetate and the carbonate ions range from 2.04 to 4.33 × 10(-4) M(-1) s(-1) and from 3.71 to 11.80 × 10(-4) M(-1) s(-1), respectively. The k-pH profile for the acetate-catalyzed reaction is bell shaped and for the carbonate-catalyzed reaction a steep curve. Both HCO3(-) and CO3(2-) ions are involved in the catalysis of the photolysis reaction in alkaline solution. The rate constants for the HCO3(-) and CO3(2-) ions catalyzed reactions are 0.72 and 1.38 × 10(-3) M(-1) s(-1), respectively, indicating a major role of CO3(2-) ions in the catalysis reaction. The loss of RF fluorescence in acetate buffer suggests an interaction between RF and acetate ions to promote the photolysis reaction. The optimum stability of RF solutions is observed in the pH range 5-6, which is suitable for pharmaceutical preparations.

  2. A Study of the Solvation Structure of L-Leucine in Alcohol-Water Binary Solvents through Molecular Dynamics Simulations and FTIR and NMR Spectroscopy.

    PubMed

    Takamuku, Toshiyuki; Hatomoto, Yohei; Tonegawa, Junko; Tsutsumi, Youichi; Umecky, Tatsuya

    2015-10-26

    The solvation structures of l-leucine (Leu) in aliphatic-alcohol-water and fluorinated-alcohol-water solvents are elucidated for various alcohol contents by using molecular dynamics (MD) simulations and IR, and (1) H and (13) C NMR spectroscopy. The aliphatic alcohols included methanol, ethanol, and 2-propanol, whereas the fluorinated alcohols were 2,2,2-trifluoroethanol and 1,1,1,3,3,3-hexafluoro-2-propanol. The MD results show that the hydrophobic alkyl moiety of Leu is surrounded by the alkyl or fluoroalkyl groups of the alcohol molecules. In particular, TFE and HFIP significantly solvate the alkyl group of Leu. IR spectra reveal that the Leu C-H stretching vibration blueshifts in fluorinated alcohol solutions with increasing alcohol content, whereas the vibration redshifts in aliphatic alcohol solutions. When the C-H stretching vibration blueshifts in the fluorinated alcohol solutions, the hydrogen and carbon atoms of the Leu alkyl group are magnetically shielded. Consequently, TFE and HFIP molecules may solvate the Leu alkyl group through the blue-shifting hydrogen bonds.

  3. Preparation of Activated Carbon From Polygonum orientale Linn. to Remove the Phenol in Aqueous Solutions

    PubMed Central

    Feng, Jia; Shi, Shengli; Pei, Liangyu; Lv, Junping; Liu, Qi; Xie, Shulian

    2016-01-01

    Phenol components are major industry contaminants of aquatic environment. Among all practical methods for removing phenol substances from polluted water, activated carbon absorption is the most effective way. Here, we have produced low-cost activated carbon using Polygonum orientale Linn, a wide spreading species with large biomass. The phenol adsorption ability of this activated carbon was evaluated at different physico-chemical conditions. Average equilibrium time for adsorption was 120 min. The phenol adsorption ability of the P. orientale activated carbon was increased as the pH increases and reached to the max at pH 9.00. By contrast, the ionic strength had little effect on the phenol absorption. The optimum dose for phenol adsorption by the P. orientale activated carbon was 20.00 g/L. The dominant adsorption mechanism of the P. orientale activated carbon was chemisorption as its phenol adsorption kinetics matched with the pseudo-second-order kinetics. In addition, the equilibrium data were fit to the Langmuir model, with the negative standard free energy and the positive enthalpy, suggesting that adsorption was spontaneous and endothermic. PMID:27741305

  4. Effect of ammonium-salt solutions on the surface properties of carbon fibers in electrochemical anodic oxidation

    NASA Astrophysics Data System (ADS)

    Qian, Xin; Wang, Xuefei; Ouyang, Qin; Chen, Yousi; Yan, Qing

    2012-10-01

    The surfaces of polyacrylonitrile-based carbon fibers were treated by an electrochemical anodic method. Three different kinds of ammonium-salt solutions namely NH4HCO3, (NH4)2CO3 and (NH4)3PO4 were respectively chosen as the electrolytes. The effect of these electrolytes on the surface structure was studied by scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). The results showed that longitudinal grooves on the fiber surface became more well-defined and much deeper after surface treatment, and the root mean square roughness (RMS) of carbon fiber surface increased from 4.6 nm for untreated fibers to 13.5 nm for treated fibers in (NH4)3PO4 electrolytes. The concentration of oxygen and nitrogen atomic on the fiber surface increased after surface treatment. The tensile strength of oxidized fibers had an obvious decrease, whereas the interlaminar shear strength (ILSS) value of corresponding carbon fiber reinforced polymers (CFRPs) increased in a large extent. The intensity of oxidative reaction varied with the change of ammonium-salt solutions and electrochemical oxidation in (NH4)3PO4 electrolyte was of the most violence. The corresponding mechanism was also discussed and the result showed that the higher the concentration of OH- ions in the electrolytes, the violent the oxidative reaction happened.

  5. Junction-Controlled Elasticity of Single-Walled Carbon Nanotube Dispersions in Acrylic Copolymer Gels and Solutions

    SciTech Connect

    Schoch, Andrew B.; Shull, Kenneth R.; Brinson, L. Catherine

    2008-08-26

    Oscillatory shear rheometry is used to study the mechanical response of single-walled carbon nanotubes dispersed in solutions of acrylic diblock or triblock copolymers in 2-ethyl-1-hexanol. Thermal transitions in the copolymer solutions provide a route for the easy processing of these composite materials, with excellent dispersion of the nanotubes as verified by near-infrared photoluminescence spectroscopy. The nanotube dispersions form elastic networks with properties that are controlled by the junction points between nanotubes, featuring a temperature-dependent elastic response that is controlled by the dynamic properties of the matrix copolymer solution. The data are consistent with the formation of micelle-like aggregates around the nanotubes. At low temperatures the core-forming poly(methyl methacrylate) blocks are glassy, and the overall mechanical response of the composite does not evolve with time. At higher temperatures the enhanced mobility of the core-forming blocks enables the junctions to achieve more intimate nanotube-nanotube contact, and the composite modulus increases with time. These aging effects are observed in both diblock and triblock copolymer solutions but are partially reversed in the triblock solutions by cooling through the gel transition of the triblock copolymer. This result is attributed to the generation of internal stresses during gelation and the ability of these stresses to break or weaken the nanotube junctions.

  6. Alcohol use disorder

    MedlinePlus

    ... Alcohol abuse; Problem drinking; Drinking problem; Alcohol addiction; Alcoholism - alcohol use; Substance use - alcohol ... The National Institute on Alcohol Abuse and Alcoholism ... 1 drink per day Men should not drink more than 2 drinks per day

  7. Activated carbons from coal/pitch and polyethylene terephthalate blends for the removal of phenols from aqueous solutions

    SciTech Connect

    Ewa Lorenc-Grabowska; Grazyna Gryglewicz; Jacek Machnikowski

    2009-05-15

    Blends of two bituminous coals and a coal-tar pitch (CTP) with polyethylene terephthalate (PET) were evaluated as precursors of activated carbons (ACs). The intensity of the interactions between the raw materials, coal/CTP and PET during copyrolysis was closely observed by means of thermogravimetric analysis. In addition, the homogeneity of the carbon matrix of the chars produced at 800{sup o}C in a horizontal oven was studied by polarized light optical microscopy. Activated carbons were prepared from single components and their blends (1:1 w/w) by subjecting them to carbonization up to 800{sup o}C in a horizontal oven and then activation with steam at 800{sup o}C to 50% burnoff. The porous structure of the ACs was determined by sorption of N{sub 2} at 77 K and of CO{sub 2} at 273 K. The PET-containing blends produced microporous activated carbons with a maximum BET surface area of nearly 1100 m{sup 2} g{sup -1} and a maximum micropore size distribution of 0.6-0.8 nm in the case of the AC from the CTP/PET blend. The addition of PET to a bituminous coal was compared with the preoxidation of coal P in air as a way to reduce thermoplasticity and to promote the development of the porous structure. The modification of bituminous coals by PET appeared to be more effective than conventional coal preoxidation treatment. The resultant ACs were tested by measuring their effectiveness in removing phenols from an aqueous solution. The adsorption of p-chlorophenol (PCP) by the ACs prepared from the PET-containing blends was slightly higher than for the commercial activated carbon. The ability to adsorb PCP was found to be related to the volume of the super-micropores.

  8. The solvation study of carbon, silicon and their mixed nanotubes in water solution.

    PubMed

    Hashemi Haeri, Haleh; Ketabi, Sepideh; Hashemianzadeh, Seyed Majid

    2012-07-01

    Nanotubes are believed to open the road toward different modern fields, either technological or biological. However, the applications of nanotubes have been badly impeded for the poor solubility in water which is especially essential for studies in the presence of living cells. Therefore, water soluble samples are in demand. Herein, the outcomes of Monte Carlo simulations of different sets of multiwall nanotubes immersed in water are reported. A number of multi wall nanotube samples, comprised of pure carbon, pure silicon and several mixtures of carbon and silicon are the subjects of study. The simulations are carried out in an (N,V,T) ensemble. The purpose of this report is to look at the effects of nanotube size (diameter) and nanotube type (pure carbon, pure silicon or a mixture of carbon and silicon) variation on solubility of multiwall nanotubes in terms of number of water molecules in shell volume. It is found that the solubility of the multi wall carbon nanotube samples is size independent, whereas multi wall silicon nanotube samples solubility varies with diameter of the inner tube. The higher solubility of samples containing silicon can be attributed to the larger atomic size of silicon atom which provides more direct contact with the water molecules. The other affecting factor is the bigger inter space (the space between inner and outer tube) in the case of silicon samples. Carbon type multi wall nanotubes appeared as better candidates for transporting water molecules through a multi wall nanotube structure, while in the case of water adsorption problems it is better to use multi wall silicon nanotubes or a mixture of multi wall carbon/ silicon nanotubes. PMID:22271095

  9. The solvation study of carbon, silicon and their mixed nanotubes in water solution.

    PubMed

    Hashemi Haeri, Haleh; Ketabi, Sepideh; Hashemianzadeh, Seyed Majid

    2012-07-01

    Nanotubes are believed to open the road toward different modern fields, either technological or biological. However, the applications of nanotubes have been badly impeded for the poor solubility in water which is especially essential for studies in the presence of living cells. Therefore, water soluble samples are in demand. Herein, the outcomes of Monte Carlo simulations of different sets of multiwall nanotubes immersed in water are reported. A number of multi wall nanotube samples, comprised of pure carbon, pure silicon and several mixtures of carbon and silicon are the subjects of study. The simulations are carried out in an (N,V,T) ensemble. The purpose of this report is to look at the effects of nanotube size (diameter) and nanotube type (pure carbon, pure silicon or a mixture of carbon and silicon) variation on solubility of multiwall nanotubes in terms of number of water molecules in shell volume. It is found that the solubility of the multi wall carbon nanotube samples is size independent, whereas multi wall silicon nanotube samples solubility varies with diameter of the inner tube. The higher solubility of samples containing silicon can be attributed to the larger atomic size of silicon atom which provides more direct contact with the water molecules. The other affecting factor is the bigger inter space (the space between inner and outer tube) in the case of silicon samples. Carbon type multi wall nanotubes appeared as better candidates for transporting water molecules through a multi wall nanotube structure, while in the case of water adsorption problems it is better to use multi wall silicon nanotubes or a mixture of multi wall carbon/ silicon nanotubes.

  10. [Adsorption Characteristics of Nitrate and Phosphate from Aqueous Solution on Zirconium-Hexadecyltrimethylammonium Chloride Modified Activated Carbon].

    PubMed

    Zheng, Wen-jing; Lin, Jian-wei; Zhan, Yan-hui; Wang, Hong

    2015-06-01

    A novel adsorbent material, i.e., zirconium-cationic surfactant modified activated carbon (ZrSMAC) was prepared by loading zirconium hydroxide and hexadecyltrimethylammonium chloride (CTAC) on activated carbon, and was used as an adsorbent for nitrate and phosphate removal from aqueous solution. The adsorption characteristics of nitrate and phosphate on ZrSMAC from aqueous solution were investigated in batch mode. Results showed that the ZrSMAC was effective for nitrate and phosphate removal from aqueous solution. The pseudo-second-order kinetic model fitted both the nitrate and phosphate kinetic experimental data well. The equilibrium isotherm data of nitrate adsorption onto the ZrSMAC were well fitted to the Langmuir, Dubinin-Radushkevich (D-R) and Freundlich isotherm models. The equilibrium isotherm data of phosphate adsorption onto the ZrSMAC could be described by the Langmuir and,D- R isotherm models. According to the Langmuir isotherm model, the maximum nitrate and phosphate adsorption capacities for the ZrSMAC were 7.58 mg x g(-1) and 10.9 mg x g(-1), respectively. High pH value was unfavorable for nitrate and phosphate adsorption onto the ZrSMAC. The presence of Cl-, HCO3- and SO4(2-) in solution reduced the nitrate and phosphate adsorption capacities for the ZrSMAC. The nitrate adsorption capacity for the ZrSMAC was reduced by the presence of coexisting phosphate in solution, and the phosphate adsorption capacity for the ZrSMAC was also reduced by the presence of coexisting nitrate in solution. About 90% of nitrate adsorbed on the ZrSMAC could be desorbed in 1 mol x L(-1) NaCl solution, and about 78% of phosphate adsorbed on the ZrSMAC could be desorbed in 1 mol x L(-1) NaOH solution. The adsorption mechanism of nitrate on the ZrSMAC included the anion exchange interactions and electrostatic attraction, and the adsorption mechanism of phosphate on the ZrSMAC included the ligand exchange interaction, electrostatic attraction and anion exchange interaction.

  11. The self-similar solutions of the problem of carbon dioxide injection into the reservoir saturated with methane and its hydrate

    NASA Astrophysics Data System (ADS)

    Musakaev, N. G.; Khasanov, M. K.

    2016-10-01

    In this paper the research of carbon dioxide injection into a porous medium initially saturated with methane and its hydrate was performed. The mathematical model of heat and mass transfer in a porous media, accompanied by the formation of carbon dioxide hydrate, is presented. The self-similar solutions, for the axisymmetric problem definition, were built. These solutions describe the distribution of the fluid parameters in a reservoir.

  12. Two competitive nucleation mechanisms of calcium carbonate biomineralization in response to surface functionality in low calcium ion concentration solution

    PubMed Central

    Deng, Hua; Wang, Shuo; Wang, Xiumei; Du, Chang; Shen, Xingcan; Wang, Yingjun; Cui, Fuzhai

    2015-01-01

    Four self-assembled monolayer surfaces terminated with –COOH, –OH, –NH2 and –CH3 functional groups are used to direct the biomineralization processes of calcium carbonate (CaCO3) in low Ca2+ concentration, and the mechanism of nucleation and initial crystallization within 12 h was further explored. On −COOH surface, nucleation occurs mainly via ion aggregation mechanism while prenucleation ions clusters may be also involved. On −OH and −NH2 surfaces, however, nucleation forms via calcium carbonate clusters, which aggregate in solution and then are adsorbed onto surfaces following with nucleation of amorphous calcium carbonate (ACC). Furthermore, strongly negative-charged −COOH surface facilitates the direct formation of calcites, and the −OH and −NH2 surfaces determine the formation of vaterites with preferred crystalline orientations. Neither ACC nor crystalline CaCO3 is observed on −CH3 surface. Our findings present a valuable model to understand the CaCO3 biomineralization pathway in natural system where functional groups composition plays a determining role during calcium carbonate crystallization. PMID:26814639

  13. Two competitive nucleation mechanisms of calcium carbonate biomineralization in response to surface functionality in low calcium ion concentration solution.

    PubMed

    Deng, Hua; Wang, Shuo; Wang, Xiumei; Du, Chang; Shen, Xingcan; Wang, Yingjun; Cui, Fuzhai

    2015-09-01

    Four self-assembled monolayer surfaces terminated with -COOH, -OH, -NH2 and -CH3 functional groups are used to direct the biomineralization processes of calcium carbonate (CaCO3) in low Ca(2+) concentration, and the mechanism of nucleation and initial crystallization within 12 h was further explored. On -COOH surface, nucleation occurs mainly via ion aggregation mechanism while prenucleation ions clusters may be also involved. On -OH and -NH2 surfaces, however, nucleation forms via calcium carbonate clusters, which aggregate in solution and then are adsorbed onto surfaces following with nucleation of amorphous calcium carbonate (ACC). Furthermore, strongly negative-charged -COOH surface facilitates the direct formation of calcites, and the -OH and -NH2 surfaces determine the formation of vaterites with preferred crystalline orientations. Neither ACC nor crystalline CaCO3 is observed on -CH3 surface. Our findings present a valuable model to understand the CaCO3 biomineralization pathway in natural system where functional groups composition plays a determining role during calcium carbonate crystallization.

  14. Corrosion inhibition behavior of propyl phosphonic acid-Zn2+ system for carbon steel in aqueous solution

    NASA Astrophysics Data System (ADS)

    Prabakaran, M.; Venkatesh, M.; Ramesh, S.; Periasamy, V.

    2013-07-01

    The effectiveness of propyl phosphonic acid (PPA) as a corrosion inhibitor in association with a bivalent cation like Zn2+ has been studied. An eco-friendly inhibitor in controlling corrosion of carbon steel in neutral aqueous medium in the absence and presence of Zn2+ has been evaluated by gravimetric method. Impedance studies of the metal/solution interface indicated that the surface film is highly protective against the corrosion of carbon steel in the aqueous environment. Potentiodynamic polarization studies showed that the inhibitor is a mixed inhibitor. X-ray photoelectron spectroscopic analysis (XPS) of the protective film exhibited the presence of the elements viz., iron, phosphorus, oxygen, carbon and zinc. The chemical shifts in the binding energies of these elements inferred that the surface film is composed of oxides/hydroxides of iron(III), Zn(OH)2 and [Fe(II)/(III)-Zn(II)-PPA] complex. Further, the surface analysis techniques viz., FT-IR, AFM and SEM studies confirm the formation of an adsorbed protective film on the carbon steel surface. Based on all these results, a plausible mechanism of corrosion inhibition is proposed.

  15. Study On Adsorption of Bromate From Aqueous Solution On Modified Activated Carbon

    NASA Astrophysics Data System (ADS)

    Liu, Tong-mian; Cui, Fu-yi; Zhao, Zhi-wei; Liu, Dong-mei; Zhu, Qi; Wang, Huan

    2010-11-01

    A coal-based activated carbon was treated chemically with nitric acid, sodium hydroxide and ammonia for its surface modification, and its adsorption capacity was investigated with bromate. Several techniques were used to characterize the physicochemical properties of these materials including BET, XPS, pHpzc and Boehm titration. The results indicated that the specific surface area of the activated carbon decreased after oxidation with nitric acid. But the amount of surface acidic oxygen-containing functional groups of the oxidized sample increased compared to the raw carbon and the points of zero charge (pHpzc) decreased. The specific surface area of the activated carbon also decreased after sodium hydroxide treatment and the points of zero charge increased. The changes of surface chemical properties after the ammonia treatment was opposite to the oxidized sample. As a result, the pHpzc of the carbon was increased to near pH9.3, the amount of surface basic groups was increased. Furthermore, the data of bromate adsorption on all the samples were fitted to the Langmuir isotherm model well which indicates monolayer adsorption. In addition, the adsorption capacity of ammonia treatment sample was the highest and its saturated adsorption capacity reached 1.55 mg/g. A strong correlation was found between basic groups and adsorption capacity of bromate. Enhancement of basic groups was favorable for bromate removal.

  16. Isolation and characterization of heterotrophic bacteria able to grow aerobically with quaternary ammonium alcohols as sole source of carbon and nitrogen.

    PubMed

    Kaech, Andres; Vallotton, Nathalie; Egli, Thomas

    2005-04-01

    The quaternary ammonium alcohols (QAAs) 2,3-dihydroxypropyl-trimethyl-ammonium (TM), dimethyl-diethanol-ammonium (DM) and methyl-triethanol-ammonium (MM) are hydrolysis products of their parent esterquat surfactants, which are widely used as softeners in fabric care. We isolated several bacteria growing with QAAs as the sole source of carbon and nitrogen. The strains were compared with a previously isolated TM-degrading bacterium, which was identified as a representative of the species Pseudomonas putida (Syst. Appl. Microbiol. 24 (2001) 252). Two bacteria were isolated with DM, referred to as strains DM 1 and DM 2, respectively. Based on 16S-rDNA analysis, they provided 97% (DM 1) and 98% (DM 2) identities to the closest related strain Zoogloea ramigera Itzigsohn 1868AL. Both strains were long, slim, motile rods but only DM 1 showed the floc forming activity, which is typical for representatives of the genus Zoogloea. Using MM we isolated a Gram-negative, non-motile rod referred to as strain MM 1. The 16S-rDNA sequence of the isolated bacterium revealed 94% identities (best match) to Rhodobacter sphaeroides only. The strains MM 1 and DM 1 exclusively grew with the QAA which was used for their isolation. DM 2 was also utilizing TM as sole source of carbon and nitrogen. However, all of the isolated bacteria were growing with the natural and structurally related compound choline. PMID:15900970

  17. Tetrahydrofuran-induced K and Li doping onto poly(furfuryl alcohol)-derived activated carbon (PFAC): Influence on microstructure and H2 sorption properties

    SciTech Connect

    Saha, Dipendu; Contescu, Cristian I; Gallego, Nidia C

    2012-01-01

    We have doped polyfurfuryl alcohol derived activated carbon (PFAC) with two alkali metals, potassium (K) and lithium (Li) by prior reacting the metals with naphthalene in presence of tetrahydrofuran (THF) followed by introducing them to pristine PFAC. THF molecule causes minor alteration in the microstructure of PFAC as confirmed by the Raman spectra, X-ray diffraction and pore textural analysis. Raman spectra and X-ray diffraction indicated a slight localized ordering towards the stacking defects of disordered carbon, like PFAC which can be attributed to the movement of THF molecules within the internal planes of graphene sheets. Pore textural analysis confirmed the lowering specific surface area and pore volume of both K and Li doped PFACs.(BET SSA: 1378 m2/g (PFAC); 1252 m2/g (K-PFAC); 1081 m2/g (Li-PFAC)) Volumetric hydrogen adsorption measurement at the temperatures of 298, 288, 273 and 77 K and pressure up to 1 bar indicated the enhanced adsorption potential imposed by the presence of alkali metals, which can be reconfirmed by the additional heats of adsorption of metal doped PFACs (Li-PFAC: -(10 - 11) kJ/mol; K-PFAC: -(16 -19) kJ/mol) compared to pristine PFAC (-9.6 kJ/mol).

  18. Analysis of the corrosion of carbon steels in simulated salt repository brines and acid chloride solutions at high temperatures

    SciTech Connect

    Diercks, D.R.; Kassner, T.F.

    1988-04-01

    An analysis of literature data on the corrosion of carbon steels in anoxic brines and acid chloride solutions was performed, and the results were used to assess the expected life of high-level nuclear waste package containers in a salt repository environment. The corrosion rate of carbon steels in moderately acidic aqueous chloride environments obeys an Arrhenius dependence on temperature and a (pH{sub 2}){sup {minus}1/2} dependence on hydrogen partial pressure. The cathodic reduction of water to produce hydrogen is the rate-controlling step in the corrosion process. An expression for the corrosion rate incorporating these two dependencies was used to estimate the corrosion life of several proposed waste package configurations. 42 refs., 11 figs., 2 tabs.

  19. Synthesis of magnetic nanoporous carbon from metal-organic framework for the fast removal of organic dye from aqueous solution

    NASA Astrophysics Data System (ADS)

    Jiao, Caina; Wang, Yanen; Li, Menghua; Wu, Qiuhua; Wang, Chun; Wang, Zhi

    2016-06-01

    In this paper, a magnetic nanoporous carbon (Fe3O4/NPC) was successfully synthesized by using MOF-5 as carbon precursor and Fe salt as magnetic precursor. The texture properties of the as-synthesized nanocomposite were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), vibration sample magnetometer (VSM), and N2 adsorption-desorption isotherms. The Fe3O4/NPC had a high surface area with strong magnetic strength. Its adsorption behavior was tested by its adsorption capacity for the removal of methylene blue from aqueous solution. The results demonstrated that the Fe3O4/NPC had a high adsorption capacity, rapid adsorption rate, and easy magnetic separabilty. Moreover, the adsorbent could be easily regenerated by washing it with ethanol. The Fe3O4/NPC can be used as a good alternative for the effective removal of organic dyes from wastewater.

  20. Origin of gasoline-range hydrocarbons and their migration by solution in carbon dioxide in Norton basin, Alaska.

    USGS Publications Warehouse

    Kvenvolden, K.A.; Claypool, G.E.

    1980-01-01

    Carbon dioxide from a submarine seep in Norton Sound carries a minor component of gas- and gasoline-range hydrocarbons. The molecular and isotopic compositions of the hydrocarbon gases and the presence of gasoline-range hydrocarbons indicate that these molecules are derived from thermal alteration of marine and/or nonmarine organic matter buried within Norton basin. The gasoline-range hydrocarbon distribution suggests that the hydrocarbon mixture is an immature petroleum-like condensate of lower temperature origin than normal crude oil. The submarine seep provides a natural example in support of a carbon dioxide solution transport mechanism thought to be operative in the migration of hydrocarbons in certain reservoirs.-Authors