Cryo-irradiation as a terminal method for the sterilization of drug aqueous solutions.

PubMed

Maquille, Aubert; Habib Jiwan, Jean-Louis; Tilquin, Bernard

2008-05-01

The aim of this study is to evaluate the specificities of the irradiation of drugs in frozen aqueous solution. The structures of the degradation products were determined to gain insight into the radiolysis mechanisms occurring in frozen aqueous solutions. Metoclopramide hydrochloride and metoprolol tartrate were chosen as models. The frozen solutions were irradiated at dry ice temperature by high energy electrons at various doses. The drug purity (chemical potency) and the radiolysis products were quantified by HPLC-DAD. Characterization of the degradation products was performed by LC-APCI-MS-MS. The structures of the radiolysis products detected in irradiated frozen aqueous solutions were compared to those detected in solid-state and aqueous solutions (previous studies). For both metoclopramide and metoprolol, solute loss upon irradiation of frozen aqueous solutions was negligible. Five radiolysis products present in traces were identified in irradiated metoclopramide frozen solutions. Three of them were previously identified in solid-state irradiated metoclopramide crystals. The two others were formed following reactions with the hydroxyl radical (indirect effect). Only one fragmentation product was observed in irradiated metoprolol frozen solutions. For both drugs, radiosterilization of frozen solutions, even at high doses (25 kGy), was found to be possible.

Noble metal superparticles and methods of preparation thereof

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

Sun, Yugang; Hu, Yongxing

A method comprises heating an aqueous solution of colloidal silver particles. A soluble noble metal halide salt is added to the aqueous solution which undergoes a redox reaction on a surface of the silver particles to form noble metal/silver halide SPs, noble metal halide/silver halide SPs or noble metal oxide/silver halide SPs on the surface of the silver particles. The heat is maintained for a predetermined time to consume the silver particles and release the noble metal/silver halide SPs, the noble metal halide/silver halide SPs or the noble metal oxide/silver halide SPs into the aqueous solution. The aqueous solution ismore » cooled. The noble metal/silver halide SPs, the noble metal halide/silver halide SPs or noble metal oxide/silver halide SPs are separated from the aqueous solution. The method optionally includes adding a soluble halide salt to the aqueous solution.« less

Hydrogen generation systems utilizing sodium silicide and sodium silica gel materials

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

Wallace, Andrew P.; Melack, John M.; Lefenfeld, Michael

Systems, devices, and methods combine reactant materials and aqueous solutions to generate hydrogen. The reactant materials can sodium silicide or sodium silica gel. The hydrogen generation devices are used in fuels cells and other industrial applications. One system combines cooling, pumping, water storage, and other devices to sense and control reactions between reactant materials and aqueous solutions to generate hydrogen. Multiple inlets of varied placement geometries deliver aqueous solution to the reaction. The reactant materials and aqueous solution are churned to control the state of the reaction. The aqueous solution can be recycled and returned to the reaction. One systemmore » operates over a range of temperatures and pressures and includes a hydrogen separator, a heat removal mechanism, and state of reaction control devices. The systems, devices, and methods of generating hydrogen provide thermally stable solids, near-instant reaction with the aqueous solutions, and a non-toxic liquid by-product.« less

Hydrogen generation systems utilizing sodium silicide and sodium silica gel materials

DOEpatents

Wallace, Andrew P.; Melack, John M.; Lefenfeld, Michael

2015-07-14

Systems, devices, and methods combine reactant materials and aqueous solutions to generate hydrogen. The reactant materials can sodium silicide or sodium silica gel. The hydrogen generation devices are used in fuels cells and other industrial applications. One system combines cooling, pumping, water storage, and other devices to sense and control reactions between reactant materials and aqueous solutions to generate hydrogen. Multiple inlets of varied placement geometries deliver aqueous solution to the reaction. The reactant materials and aqueous solution are churned to control the state of the reaction. The aqueous solution can be recycled and returned to the reaction. One system operates over a range of temperatures and pressures and includes a hydrogen separator, a heat removal mechanism, and state of reaction control devices. The systems, devices, and methods of generating hydrogen provide thermally stable solids, near-instant reaction with the aqueous solutions, and a non-toxic liquid by-product.

Conversion of depleted uranium hexafluoride to a solid uranium compound

DOEpatents

Rothman, Alan B.; Graczyk, Donald G.; Essling, Alice M.; Horwitz, E. Philip

2001-01-01

A process for converting UF.sub.6 to a solid uranium compound such as UO.sub.2 and CaF. The UF.sub.6 vapor form is contacted with an aqueous solution of NH.sub.4 OH at a pH greater than 7 to precipitate at least some solid uranium values as a solid leaving an aqueous solution containing NH.sub.4 OH and NH.sub.4 F and remaining uranium values. The solid uranium values are separated from the aqueous solution of NH.sub.4 OH and NH.sub.4 F and remaining uranium values which is then diluted with additional water precipitating more uranium values as a solid leaving trace quantities of uranium in a dilute aqueous solution. The dilute aqueous solution is contacted with an ion-exchange resin to remove substantially all the uranium values from the dilute aqueous solution. The dilute solution being contacted with Ca(OH).sub.2 to precipitate CaF.sub.2 leaving dilute NH.sub.4 OH.

SEPARATION OF RUTHENIUM FROM AQUEOUS SOLUTIONS

DOEpatents

Beederman, M.; Vogler, S.; Hyman, H.H.

1959-07-14

The separation of rathenium from a rathenium containing aqueous solution is described. The separation is accomplished by adding sodium nitrite, silver nitrate and ozone to the ruthenium containing aqueous solution to form ruthenium tetroxide and ihen volatilizing off the ruthenium tetroxide.

SEPARATION OF POLONIUM, PROTACTINIUM OR MIXTURES THEREOF IN AQUEOUS SOLUTION FROM BISMUTH, LEAD, ZIRCONIUM AND/OR COLUMBIUM VALUES

DOEpatents

Van Winkle, Q.; Kraus, K.A.

1959-10-27

A process is presented for separating polonium, protactinium, or mixtures thereof in aqueous solution from bismuth, zirconium, lead, and niobium values contained in the solution. The method comprises providing hydrochloric acid in the solution in a concentration of at least 5N. contacting the aqueous solution with a substantially waterimmiscible organic solvent such as diisopropyl ketone, and separating the aqueous phase containing the bismuth, zirconium, lead, and niobium from the organic extract phase containing the polonium, protactinium, or mixture thereof.

RECOVERY OF ACTINIDES FROM AQUEOUS NITRIC ACID SOLUTIONS

DOEpatents

Ader, M.

1963-11-19

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

ENGINEERING BULLETIN: AIR STRIPPING OF AQUEOUS SOLUTIONS

EPA Science Inventory

Air striding is a means to transfer contaminants from aqueous solutions to air. ontaminants are not destroyed by air stripping but are physically separated from the aqueous solutions. ontaminant vapors are transferred into the air stream and, if necessary, can be treated by incin...

Metal separations using aqueous biphasic partitioning systems

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

Chaiko, D.J.; Zaslavsky, B.; Rollins, A.N.

1996-05-01

Aqueous biphasic extraction (ABE) processes offer the potential for low-cost, highly selective separations. This countercurrent extraction technique involves selective partitioning of either dissolved solutes or ultrafine particulates between two immiscible aqueous phases. The extraction systems that the authors have studied are generated by combining an aqueous salt solution with an aqueous polymer solution. They have examined a wide range of applications for ABE, including the treatment of solid and liquid nuclear wastes, decontamination of soils, and processing of mineral ores. They have also conducted fundamental studies of solution microstructure using small angle neutron scattering (SANS). In this report they reviewmore » the physicochemical fundamentals of aqueous biphase formation and discuss the development and scaleup of ABE processes for environmental remediation.« less

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

NASA Astrophysics Data System (ADS)

Fukushima, Kunio; Watanabe, Toshiaki; Umemura, Matome

1986-08-01

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

SOLVENT EXTRACTION PROCESS FOR SEPARATING ACTINIDE AND LANTHANIDE METAL VALUES

DOEpatents

Hildebrandt, R.A.; Hyman, H.H.; Vogler, S.

1962-08-14

A process of countercurrently extracting an aqueous mineral acid feed solution for the separation of actinides from lanthanides dissolved therern is described. The feed solution is made acid-defrcient with alkali metal hydroxide prior to.contact with acid extractant; during extraction, however, acid is transferred from organic to aqueous solution and the aqueous solution gradually becomes acid. The acid-deficient phase ' of the process promotes the extraction of the actinides, while the latter acid phase'' of the process improves retention of the lanthanides in the aqueous solution. This provides for an improved separation. (AEC)

Measurements of thermodynamic and optical properties of selected aqueous organic and organic-inorganic mixtures of atmospheric relevance.

PubMed

Lienhard, Daniel M; Bones, David L; Zuend, Andreas; Krieger, Ulrich K; Reid, Jonathan P; Peter, Thomas

2012-10-11

Atmospheric aerosol particles can exhibit liquid solution concentrations supersaturated with respect to the dissolved organic and inorganic species and supercooled with respect to ice. In this study, thermodynamic and optical properties of sub- and supersaturated aqueous solutions of atmospheric interest are presented. The density, refractive index, water activity, ice melting temperatures, and homogeneous ice freezing temperatures of binary aqueous solutions containing L(+)-tartaric acid, tannic acid, and levoglucosan and ternary aqueous solutions containing levoglucosan and one of the salts NH(4)HSO(4), (NH(4))(2)SO(4), and NH(4)NO(3) have been measured in the supersaturated concentration range for the first time. In addition, the density and refractive index of binary aqueous citric acid and raffinose solutions and the glass transition temperatures of binary aqueous L(+)-tartaric acid and levoglucosan solutions have been measured. The data presented here are derived from experiments on single levitated microdroplets and bulk solutions and should find application in thermodynamic and atmospheric aerosol models as well as in food science applications.

Aqueous Plasma Pharmacy: Preparation Methods, Chemistry, and Therapeutic Applications

PubMed Central

Joslin, Jessica M.; McCall, James R.; Bzdek, Justin P.; Johnson, Derek C.; Hybertson, Brooks M.

2017-01-01

Plasma pharmacy is a subset of the broader field of plasma medicine. Although not strictly defined, the term aqueous plasma pharmacy (APP) is used to refer to the generation and distribution of reactive plasma-generated species in an aqueous solution followed by subsequent administration for therapeutic benefits. APP attempts to harness the therapeutic effects of plasma-generated oxidant species within aqueous solution in various applications, such as disinfectant solutions, cell proliferation related to wound healing, and cancer treatment. The subsequent use of plasma-generated solutions in the APP approach facilitates the delivery of reactive plasma species to internal locations within the body. Although significant efforts in the field of plasma medicine have concentrated on employing direct plasma plume exposure to cells or tissues, here we focus specifically on plasma discharge in aqueous solution to render the solution biologically active for subsequent application. Methods of plasma discharge in solution are reviewed, along with aqueous plasma chemistry and the applications for APP. The future of the field also is discussed regarding necessary research efforts that will enable commercialization for clinical deployment. PMID:28428835

Photoproduction of hydroxyl radicals in aqueous solution with algae under high-pressure mercury lamp.

PubMed

Liu, Xianli; Wu, Feng; Deng, Nansheng

2004-01-01

Photoproduction of hydroxyl radicals (*OH) could be induced in aqueous solution with algae (Nitzschia hantzschiana, etc.) and (or not) Fe3+ under high-pressure mercury lamp with an exposure time of 4 h. *OH was determined by HPLC using benzene as a probe. The photoproduction of *OH increased with increasing algae concentration. Fe3+ could enhance the photoproduction of *OH in aqueous solution with algae. The results showed that the photoproduction of *OH in algal solution with Fe3+ was greater than that in algal solution without Fe3+. The light intensity and pH affected the photoproduction of *OH in aqueous solution with algae with/without Fe3+. The photoproduction of *OH in aqueous solution with algae and Fe3+ under 250 W was greater than that under 125 W HPML. The photoproduction of *OH in algal solution (pH ranged from 4.0 to 7.0) with (or not) Fe3+ at pH 4 was the greatest.

Germanium films by polymer-assisted deposition

DOEpatents

Jia, Quanxi; Burrell, Anthony K.; Bauer, Eve; Ronning, Filip; McCleskey, Thomas Mark; Zou, Guifu

2013-01-15

Highly ordered Ge films are prepared directly on single crystal Si substrates by applying an aqueous coating solution having Ge-bound polymer onto the substrate and then heating in a hydrogen-containing atmosphere. A coating solution was prepared by mixing water, a germanium compound, ethylenediaminetetraacetic acid, and polyethyleneimine to form a first aqueous solution and then subjecting the first aqueous solution to ultrafiltration.

Tested Demonstrations. Color, Solubility, and Complex Ion Equilibria of Nickel (II) Species in Aqueous Solution.

ERIC Educational Resources Information Center

Gilbert, George L., Ed.; And Others

1980-01-01

Presents three different procedures in which reagents are added in a specified order to a large beaker containing an aqueous solution of nickel sulfate. Complex ions of nickel (II) are prepared by using aqueous solutions of ammonia, ethylenediamine, dimethylglyoxime, and cyanide ion. (CS)

Process for recovering chaotropic anions from an aqueous solution also containing other ions

DOEpatents

Rogers, Robin; Horwitz, E. Philip; Bond, Andrew H.

1999-01-01

A solid/liquid process for the separation and recovery of chaotropic anions from an aqueous solution is disclosed. The solid support comprises separation particles having surface-bonded poly(ethylene glycol) groups, whereas the aqueous solution from which the chaotropic anions are separated contains a poly(ethylene glycol) liquid/liquid biphase-forming amount of a dissolved salt (lyotrope). A solid/liquid phase admixture of separation particles containing bound chaotropic anions in such an aqueous solution is also contemplated, as is a chromatography apparatus containing that solid/liquid phase admixture.

Process for recovering chaotropic anions from an aqueous solution also containing other ions

DOEpatents

Rogers, R.; Horwitz, E.P.; Bond, A.H.

1999-03-30

A solid/liquid process for the separation and recovery of chaotropic anions from an aqueous solution is disclosed. The solid support comprises separation particles having surface-bonded poly(ethylene glycol) groups, whereas the aqueous solution from which the chaotropic anions are separated contains a poly(ethylene glycol) liquid/liquid biphase-forming amount of a dissolved salt (lyotrope). A solid/liquid phase admixture of separation particles containing bound chaotropic anions in such an aqueous solution is also contemplated, as is a chromatography apparatus containing that solid/liquid phase admixture. 19 figs.

Multi-level Quantum Mechanics and Molecular Mechanics Study of Ring Opening Process of Guanine Damage by Hydroxyl Radical in Aqueous Solution.

PubMed

Liu, Peng; Wang, Qiong; Niu, Meixing; Wang, Dunyou

2017-08-10

Combining multi-level quantum mechanics theories and molecular mechanics with an explicit water model, we investigated the ring opening process of guanine damage by hydroxyl radical in aqueous solution. The detailed, atomic-level ring-opening mechanism along the reaction pathway was revealed in aqueous solution at the CCSD(T)/MM levels of theory. The potentials of mean force in aqueous solution were calculated at both the DFT/MM and CCSD(T)/MM levels of the theory. Our study found that the aqueous solution has a significant effect on this reaction in solution. In particular, by comparing the geometries of the stationary points between in gas phase and in aqueous solution, we found that the aqueous solution has a tremendous impact on the torsion angles much more than on the bond lengths and bending angles. Our calculated free-energy barrier height 31.6 kcal/mol at the CCSD(T)/MM level of theory agrees well with the one obtained based on gas-phase reaction profile and free energies of solvation. In addition, the reaction path in gas phase was also mapped using multi-level quantum mechanics theories, which shows a reaction barrier at 19.2 kcal/mol at the CCSD(T) level of theory, agreeing very well with a recent ab initio calculation result at 20.8 kcal/mol.

Method for Non-Invasive Determination of Chemical Properties of Aqueous Solutions

NASA Technical Reports Server (NTRS)

Jones, Alan (Inventor); Thomas, Nathan A. (Inventor); Todd, Paul W. (Inventor)

2016-01-01

A method for non-invasively determining a chemical property of an aqueous solution is provided. The method provides the steps of providing a colored solute having a light absorbance spectrum and transmitting light through the colored solute at two different wavelengths. The method further provides the steps of measuring light absorbance of the colored solute at the two different transmitted light wavelengths, and comparing the light absorbance of the colored solute at the two different wavelengths to determine a chemical property of an aqueous solution.

Characteristics of regenerated nanocellulosic fibers from cellulose dissolution in aqueous solutions for wood fiber/polypropylene composites

Treesearch

Sangyeob Lee; Hui Pan; Chung Y. Hse; Alfred R. Gunasekaran; Todd F. Shupe

2014-01-01

The effects of aqueous solutions were evaluated on the properties of regenerated cellulosic nanofibers prepared from pure cellulose fibers in various formulations of aqueous solutions. Thermoplastic composites were prepared with reinforcement of the regenerated cellulosic nanofibers. The regenerated cellulosic fibers from cellulosic woody biomass were obtained from...

URANIUM SEPARATION PROCESS

DOEpatents

McVey, W.H.; Reas, W.H.

1959-03-10

The separation of uranium from an aqueous solution containing a water soluble uranyl salt is described. The process involves adding an alkali thiocyanate to the aqueous solution, contacting the resulting solution with methyl isobutyl ketons and separating the resulting aqueous and organic phase. The uranium is extracted in the organic phase as UO/sub 2/(SCN)/sub/.

SEPARATION OF RUTHENIUM FROM AQUEOUS SOLUTIONS

DOEpatents

Callis, C.F.; Moore, R.L.

1959-09-01

>The separation of ruthenium from aqueous solutions containing uranium plutonium, ruthenium, and fission products is described. The separation is accomplished by providing a nitric acid solution of plutonium, uranium, ruthenium, and fission products, oxidizing plutonium to the hexavalent state with sodium dichromate, contacting the solution with a water-immiscible organic solvent, such as hexone, to extract plutonyl, uranyl, ruthenium, and fission products, reducing with sodium ferrite the plutonyl in the solvent phase to trivalent plutonium, reextracting from the solvent phase the trivalent plutonium, ruthenium, and some fission products with an aqueous solution containing a salting out agent, introducing ozone into the aqueous acid solution to oxidize plutonium to the hexavalent state and ruthenium to ruthenium tetraoxide, and volatizing off the ruthenium tetraoxide.

SE-72/AS-72 generator system based on Se extraction/ As reextraction

DOEpatents

Fassbender, Michael Ernst; Ballard, Beau D

2013-09-10

The preparation of a .sup.72Se/.sup.72As radioisotope generator involves forming an acidic aqueous solution of an irradiated alkali bromide target such as a NaBr target, oxidizing soluble bromide in the solution to elemental bromine, removing the elemental bromine, evaporating the resulting solution to a residue, removing hydrogen chloride from the residue, forming an acidic aqueous solution of the residue, adding a chelator that selectively forms a chelation complex with selenium, and extracting the chelation complex from the acidic aqueous solution into an organic phase. As the .sup.72Se generates .sup.72As in the organic phase, the .sup.72As may be extracted repeatedly from the organic phase with an aqueous acid solution.

Methods and systems for utilizing carbide lime or slag

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

Devenney, Martin; Fernandez, Miguel; Chen, Irvin

Provided herein are methods comprising a) treating a slag solid or carbide lime suspension with an ammonium salt in water to produce an aqueous solution comprising calcium salt, ammonium salt, and solids; b) contacting the aqueous solution with carbon dioxide from an industrial process under one or more precipitation conditions to produce a precipitation material comprising calcium carbonate and a supernatant aqueous solution wherein the precipitation material and the supernatant aqueous solution comprise residual ammonium salt; and c) removing and optionally recovering ammonia and/or ammonium salt using one or more steps of (i) recovering a gas exhaust stream comprising ammoniamore » during the treating and/or the contacting step; (ii) recovering the residual ammonium salt from the supernatant aqueous solution; and (iii) removing and optionally recovering the residual ammonium salt from the precipitation material.« less

Unique role of ionic liquid [bmin][BF 4] during curcumin-surfactant association and micellization of cationic, anionic and non-ionic surfactant solutions

NASA Astrophysics Data System (ADS)

Patra, Digambara; Barakat, Christelle

2011-09-01

Hydrophilic ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroburate, modified the properties of aqueous surfactant solutions associated with curcumin. Because of potential pharmaceutical applications as an antioxidant, anti-inflammatory and anti-carcinogenic agent, curcumin has received ample attention as potential drug. The interaction of curcumin with various charged aqueous surfactant solutions showed it exists in deprotonated enol form in surfactant solutions. The nitro and hydroxyl groups of o-nitrophenol interact with the carbonyl and hydroxyl groups of the enol form of curcumin by forming ground state complex through hydrogen bonds and offered interesting information about the nature of the interactions between the aqueous surfactant solutions and curcumin depending on charge of head group of the surfactant. IL[bmin][BF 4] encouraged early formation of micelle in case of cationic and anionic aqueous surfactant solutions, but slightly prolonged micelle formation in the case of neutral aqueous surfactant solution. However, for curcumin IL [bmin][BF 4] favored strong association (7-fold increase) with neutral surfactant solution, marginally supported association with anionic surfactant solution and discouraged (˜2-fold decrease) association with cationic surfactant solution.

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

PubMed

Sekiya, S; Ohmori, K; Harii, K

1997-01-01

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

Preparing polymeric matrix composites using an aqueous slurry technique

NASA Technical Reports Server (NTRS)

Johnston, Norman J. (Inventor); Towell, Timothy W. (Inventor)

1993-01-01

An aqueous process was developed to prepare a consolidated composite laminate from an aqueous slurry. An aqueous poly(amic acid) surfactant solution was prepared by dissolving a poly(amic acid) powder in an aqueous ammonia solution. A polymeric powder was added to this solution to form a slurry. The slurry was deposited on carbon fiber to form a prepreg which was dried and stacked to form a composite laminate. The composite laminate was consolidated using pressure and was heated to form the polymeric matrix. The resulting composite laminate exhibited high fracture toughness and excellent consolidation.

Insights into water-mediated ion clustering in aqueous CaSO4 solutions: pre-nucleation cluster characteristics studied by ab initio calculations and molecular dynamics simulations.

PubMed

Li, Hui-Ji; Yan, Dan; Cai, Hou-Qin; Yi, Hai-Bo; Min, Xiao-Bo; Xia, Fei-Fei

2017-05-10

The molecular structure of growth units building crystals is a fundamental issue in the crystallization processes from aqueous solutions. In this work, a systematic investigation of pre-nucleation clusters and their hydration characteristics in aqueous CaSO 4 solutions was performed using ab initio calculations and molecular dynamics (MD) simulations. The results of ab initio calculations and MD simulations indicate that the dominant species in aqueous CaSO 4 solutions are monodentate ion-associated structures. Compared with charged ion clusters, neutral clusters are more likely to be present in an aqueous CaSO 4 solution. Neutral (CaSO 4 ) m clusters are probably the growth units involved in the pre-nucleation or crystallization processes. Meanwhile, hydration behavior around ion associated species in aqueous CaSO 4 solutions plays an important role in related phase/polymorphism selections. Upon ion clustering, the residence of some water molecules around Ca 2+ in ion-associated species is weakened while that of some bridging waters is enhanced due to dual interaction by Ca 2+ and SO 4 2- . Some phase/polymorphism selections can be achieved in aqueous CaSO 4 solutions by controlling the hydration around pre-nucleation clusters. Moreover, the association trend between calcium and sulfate is found to be relatively strong, which hints at the low solubility of calcium sulfate in water.

[Analysis of parameters of serum concentration and pharmacokinetic of liposome and aqueous solution of toatal ginsenoside of ginseng stems and leaves in rats].

PubMed

Zha, Lin; Zhao, Yan; Zhu, Hong-Yan; Cai, En-Bo; Liu, Shuang-Li; Yang, He; Zhao, Ying; Gao, Yu-Gang; Zhang, Lian-Xue

2017-05-01

The experiment was aimed to investigate the difference of plasma concentration and pharmacokinetic parameters between liposome and aqueous solution of toatal ginsenoside of ginseng stems and leaves in rats, such as ginsenosides Rg₁, Re, Rf, Rb₁, Rg₂, Rc, Rb₂, Rb₃, Rd. After intravenous injection of liposome and aqueous solution in rats, the blood was taken from the femoral vein to detect the plasma concentration of the above 9 ginsenoside monomers in different time points by using HPLC. The concentration-time curve was obtained and 3p97 pharmacokinetic software was used to get the pharmacokinetic parameters. After the intravenous injection of ginsenosides to rats, nine ginsenosides were detected in plasma. In general, among these ginsenosides, the peak time of the aqueous solution was between 0.05 to 0.083 3 h, and the serum concentration peak of liposome usually appeared after 0.5 h. After software fitting, the aqueous solution of ginsenoside monomers Rg₁, Re, Rf, Rg₂, Rc, Rd, Rb₃ was two-compartment model, and the liposomes were one-compartment model; aqueous solution and liposome of ginsenoside monomers Rb₁ were three-compartment model; aqueous solution of ginsenoside monomers Rb₂ was three-compartment model, and its liposome was one-compartment model. Area under the drug time curve (AUC) of these 9 kinds of saponin liposomes was larger than that of aqueous solution, and the retention time of the liposomes was longer than that of the aqueous solution; the removal rate was slower than that of the aqueous solution, and the half-life was longer than that of the water solution. The results from the experiment showed that by intravenous administration, the pharmacokinetic parameters of two formulations were significantly different from each other; the liposomes could not only remain the drug for a longer time in vivo, but also reduce the elimination rate and increase the treatment efficacy. As compared with the traditional dosage forms, the total ginsenoside of ginseng stems and leaves can improve the sustained release of the drug, which is of great significance for the research and development of new dosage forms of ginsenosides in the future. Copyright© by the Chinese Pharmaceutical Association.

Thermodynamic properties of potassium chloride aqueous solutions

NASA Astrophysics Data System (ADS)

Zezin, Denis; Driesner, Thomas

2017-04-01

Potassium chloride is a ubiquitous salt in natural fluids, being the second most abundant dissolved salt in many geological aqueous solutions after sodium chloride. It is a simple solute and strong electrolyte easily dissociating in water, however the thermodynamic properties of KCl aqueous solutions were never correlated with sufficient accuracy for a wide range of physicochemical conditions. In this communication we propose a set of parameters for a Pitzer-type model which allows calculation of all necessary thermodynamic properties of KCl solution, namely excess Gibbs free energy and derived activity coefficient, apparent molar enthalpy, heat capacity and volume, as well as osmotic coefficient and activity of water in solutions. The system KCl-water is one of the best studied aqueous systems containing electrolytes. Although extensive experimental data were collected for thermodynamic properties of these solutions over the years, the accurate volumetric data became available only recently, thus making possible a complete thermodynamic formulation including a pressure dependence of excess Gibbs free energy and derived properties of the KCl-water liquids. Our proposed model is intended for calculation of major thermodynamic properties of KCl aqueous solutions at temperatures ranging from freezing point of a solution to 623 K, pressures ranging from saturated water vapor up to 150 MPa, and concentrations up to the salt saturation. This parameterized model will be further implemented in geochemical software packages and can facilitate the calculation of aqueous equilibrium for reactive transport codes.

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.

Exploratory studies on some electrochemical cell systems

NASA Astrophysics Data System (ADS)

Chaudhuri, Srikumar; Guha, D.

Exploratory studies were conducted on cell systems with different metal anodes, and iodine and sulphur mixed with graphite powder in a polymer matrix as cathodes, using different electrolytes in non-aqueous and aqueous media as ionic charge carriers. The electrical conductance of the electrolyte solutions in aqueous and non-aqueous solvents, the open circuit voltage (OCV) and short circuit current (SCC) for the different cell systems were measured. To date, the non-aqueous solvents used in our studies were dimethylformamide, formamide, dioxan, and nitrobenzene, and the electrolytes used were potassium iodide, caustic potash, cetyltrimethylammonium bromide (CTAB), sodium lauryl sulphate (SLS) and calcium chloride. These electrolytes were used in both non-aqueous and aqueous media. In general, aqueous electrolyte solutions gave a better performance than non-aqueous electrolyte solutions. Of the aqueous electrolytes, the highest conductance was shown by potassium chloride solution in water (conductance=0.0334 mho). However, the best OCV and SCC were shown by aluminium as anode and iodine as cathode with a saturated solution of caustic potash in water. The OCV was 1.85 V and the SCC was 290 mA cm -2. The highest conductance among the non-aqueous systems was shown by caustic potash in formamide. (Conductance=0.013 mho.) The best OCV and SCC, however, were shown by a zinc anode and iodine cathode with saturated potassium chloride in formamide, having an OCV of 1.55 V and an SCC of 150 mA cm -2. Further studies are in progress to obtain detailed performance data and recharging characteristics of some of the more promising systems reported here.

SEPARATION OF PLUTONIUM FROM AQUEOUS SOLUTIONS BY ION-EXCHANGE

DOEpatents

Schubert, J.

1958-06-01

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

A study on lithium/air secondary batteries-Stability of the NASICON-type lithium ion conducting solid electrolyte in alkaline aqueous solutions

NASA Astrophysics Data System (ADS)

Shimonishi, Yuta; Zhang, Tao; Imanishi, Nobuyuki; Im, Dongmin; Lee, Dong Joon; Hirano, Atsushi; Takeda, Yasuo; Yamamoto, Osamu; Sammes, Nigel

The stability of the high lithium ion conducting glass ceramics, Li 1+ x+ yTi 2- xAl xSi yP 3- yO 12 (LTAP) in alkaline aqueous solutions with and without LiCl has been examined. A significant conductivity decrease of the LTAP plate immersed in 0.057 M LiOH aqueous solution at 50 °C for 3 weeks was observed. However, no conductivity change of the LTAP plate immersed in LiCl saturated LiOH aqueous solutions at 50 °C for 3 weeks was observed. The pH value of the LiCl-LiOH-H 2O solution with saturated LiCl was in a range of 7-9. The molarity of LiOH and LiCl in the LiOH and LiCl saturated aqueous solution were estimated to be 5.12 and 11.57 M, respectively, by analysis of Li + and OH -. The high concentration of LiOH and the low pH value of 8.14 in this solution suggested that the dissociation of LiOH into Li + and OH - is too low in the solution with a high concentration of Li +. These results suggest that the water stable LTAP could be used as a protect layer of the lithium metal anode in the lithium/air cell with LiCl saturated aqueous solution as the electrolyte, because the content of OH - ions in the LiCl saturated aqueous solution does not increase via the cell reaction of Li + 1/2O 2 + H 2O → 2LiOH, and LTAP is stable under a deep discharge state.

Hydrogen generation systems and methods utilizing sodium silicide and sodium silica gel materials

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

Wallace, Andrew P.; Melack, John M.; Lefenfeld, Michael

Systems, devices, and methods combine thermally stable reactant materials and aqueous solutions to generate hydrogen and a non-toxic liquid by-product. The reactant materials can sodium silicide or sodium silica gel. The hydrogen generation devices are used in fuels cells and other industrial applications. One system combines cooling, pumping, water storage, and other devices to sense and control reactions between reactant materials and aqueous solutions to generate hydrogen. Springs and other pressurization mechanisms pressurize and deliver an aqueous solution to the reaction. A check valve and other pressure regulation mechanisms regulate the pressure of the aqueous solution delivered to the reactantmore » fuel material in the reactor based upon characteristics of the pressurization mechanisms and can regulate the pressure of the delivered aqueous solution as a steady decay associated with the pressurization force. The pressure regulation mechanism can also prevent hydrogen gas from deflecting the pressure regulation mechanism.« less

Environment-Friendly Post-Treatment of PEDOT-Tos Films by Aqueous Vitamin C Solutions for Tuning of Thermoelectric Properties

NASA Astrophysics Data System (ADS)

Khan, Ezaz Hasan; Thota, Sammaiah; Wang, Yiwen; Li, Lian; Wilusz, Eugene; Osgood, Richard; Kumar, Jayant

2018-04-01

Aqueous vitamin C solution has been used as an environment-friendly reducing agent for tuning the thermoelectric properties of p-toluenesulfonate-doped poly(3,4-ethylenedioxythiophene) (PEDOT-Tos) films. The de-doping of the PEDOT-Tos films by aqueous vitamin C solutions led to a decrease in the electrical conductivity of the films. The measured ultraviolet-visible-near-infrared and x-ray photoelectron spectra clearly indicated the reduction in the oxidation level from 37 to 23% when the PEDOT-Tos films were treated with 5% (w/v) aqueous vitamin C solutions. An increase in the Seebeck coefficient was measured, resulting in an increase in the figure-of-merit (ZT). A 42% increase in ZT was determined for the 5% aqueous vitamin C solution-treated PEDOT-Tos films with respect to that of the untreated films.

Hydrogen generation systems and methods utilizing sodium silicide and sodium silica gel materials

DOEpatents

Wallace, Andrew P.; Melack, John M.; Lefenfeld, Michael

2015-08-11

Systems, devices, and methods combine thermally stable reactant materials and aqueous solutions to generate hydrogen and a non-toxic liquid by-product. The reactant materials can sodium silicide or sodium silica gel. The hydrogen generation devices are used in fuels cells and other industrial applications. One system combines cooling, pumping, water storage, and other devices to sense and control reactions between reactant materials and aqueous solutions to generate hydrogen. Springs and other pressurization mechanisms pressurize and deliver an aqueous solution to the reaction. A check valve and other pressure regulation mechanisms regulate the pressure of the aqueous solution delivered to the reactant fuel material in the reactor based upon characteristics of the pressurization mechanisms and can regulate the pressure of the delivered aqueous solution as a steady decay associated with the pressurization force. The pressure regulation mechanism can also prevent hydrogen gas from deflecting the pressure regulation mechanism.

Application of Molecular Dynamics Simulations in Molecular Property Prediction II: Diffusion Coefficient

PubMed Central

Wang, Junmei; Hou, Tingjun

2011-01-01

In this work, we have evaluated how well the General AMBER force field (GAFF) performs in studying the dynamic properties of liquids. Diffusion coefficients (D) have been predicted for 17 solvents, 5 organic compounds in aqueous solutions, 4 proteins in aqueous solutions, and 9 organic compounds in non-aqueous solutions. An efficient sampling strategy has been proposed and tested in the calculation of the diffusion coefficients of solutes in solutions. There are two major findings of this study. First of all, the diffusion coefficients of organic solutes in aqueous solution can be well predicted: the average unsigned error (AUE) and the root-mean-square error (RMSE) are 0.137 and 0.171 ×10−5 cm−2s−1, respectively. Second, although the absolute values of D cannot be predicted, good correlations have been achieved for 8 organic solvents with experimental data (R2 = 0.784), 4 proteins in aqueous solutions (R2 = 0.996) and 9 organic compounds in non-aqueous solutions (R2 = 0.834). The temperature dependent behaviors of three solvents, namely, TIP3P water, dimethyl sulfoxide (DMSO) and cyclohexane have been studied. The major MD settings, such as the sizes of simulation boxes and with/without wrapping the coordinates of MD snapshots into the primary simulation boxes have been explored. We have concluded that our sampling strategy that averaging the mean square displacement (MSD) collected in multiple short-MD simulations is efficient in predicting diffusion coefficients of solutes at infinite dilution. PMID:21953689

Electrophotolysis oxidation system for measurement of organic concentration in water

NASA Technical Reports Server (NTRS)

Winkler, H. E. (Inventor)

1981-01-01

Methods and apparatus for determining organic carbon in aqueous solution are described. The method comprises subjecting the aqueous solution to electrolysis, for generating oxygen from water, and simultaneously to ultraviolet radiation, for oxidation of substantially all organic carbon to carbon dioxide. The carbon dioxide is measured and the value is related to the concentration of organic carbon in the aqueous solution.

RECOVERY AND SEPARATION OF LITHIUM VALUES FROM SALVAGE SOLUTIONS

DOEpatents

Hansford, D.L.; Raabe, E.W.

1963-08-20

Lithium values can be recovered from an aqueous basic solution by reacting the values with a phosphate salt soluble in the solution, forming an aqueous slurry of the resultant aqueous insoluble lithium phosphate, contacting the slurry with an organic cation exchange resin in the acid form until the slurry has been clarified, and thereafter recovering lithium values from the resin. (AEC)

Prediction of the glass transition in aqueous solutions of simple amides by molecular dynamics simulations

NASA Astrophysics Data System (ADS)

Kreck, Cara A.; Mandumpal, Jestin B.; Mancera, Ricardo L.

2011-01-01

Some simple amides in aqueous solution are used in the cryopreservation of biological tissues as they are believed to promote the vitrification of water, inhibiting its crystallisation and the ensuing damage from ice formation. Molecular dynamics annealing simulations reveal a broadening in the glass transition of aqueous acetamide and N-methylacetamide solutions, suggesting a thermodynamic stabilisation of the glassy state, which may be responsible for their increased tendency of vitrification and their cryoprotective ability. By contrast, aqueous formamide solutions do not exhibit broadening of the glass transition; instead, it is shifted to lower temperatures, which explains their lack of vitrification properties.

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

NASA Astrophysics Data System (ADS)

Sharma, Ravi; Thakur, R. C.

2017-07-01

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

Ultrafast fluorescence quenching dynamics of Atto655 in the presence of N-acetyltyrosine and N-acetyltryptophan in aqueous solution: proton-coupled electron transfer versus electron transfer.

PubMed

Zhang, Ying; Yuan, Shuwei; Lu, Rong; Yu, Anchi

2013-06-20

We studied the ultrafast fluorescence quenching dynamics of Atto655 in the presence of N-acetyltyrosine (AcTyr) and N-acetyltryptophan (AcTrp) in aqueous solution with femtosecond transient absorption spectroscopy. We found that the charge-transfer rate between Atto655 and AcTyr is about 240 times smaller than that between Atto655 and AcTrp. The pH value and D2O dependences of the excited-state decay kinetics of Atto655 in the presence of AcTyr and AcTrp reveal that the quenching of Atto655 fluorescence by AcTyr in aqueous solution is via a proton-coupled electron-transfer (PCET) process and that the quenching of Atto655 fluorescence by AcTrp in aqueous solution is via an electron-transfer process. With the version of the semiclassical Marcus ET theory, we derived that the electronic coupling constant for the PCET reaction between Atto655 and AcTyr in aqueous solution is 8.3 cm(-1), indicating that the PCET reaction between Atto655 and AcTyr in aqueous solution is nonadiabatic.

Method and apparatus for synthesizing anhydrous HNO.sub.3

DOEpatents

Coon, Clifford L.; Harrar, Jackson E.; Pearson, Richard K.; McGuire, Raymond R.

1984-01-01

A method and apparatus for electrochemically synthesizing anhydrous HNO.sub.3 from an aqueous solution of HNO.sub.3 includes oxidizing a solution of N.sub.2 O.sub.4 /aqueous HNO.sub.3 at an anode, while maintaining a controlled potential between the N.sub.2 O.sub.4 /aqueous HNO.sub.3 solution and the anode. A potential of about 1.80V vs. SCE is preferred. Anhydrous or aqueous HNO.sub.3 may be disposed at the cathode within the electrochemical cell. Aqueous HNO.sub.3 having a water content of up to about 12% by weight is utilized to synthesize anhydrous HNO.sub.3.

Method and apparatus for synthesizing anhydrous HNO/sub 3/. [Patent application

DOEpatents

Coon, C.L.; Harrar, J.E.; Pearson, R.K.; McGuire, R.R.

1982-07-20

A method and apparatus for electrochemically synthesizing anhydrous HNO/sub 3/ from an aqueous solution of HNO/sub 3/- includes oxidizing a solution of N/sub 2/O/sub 4//aqueous HNO/sub 3/ at an anode, while maintaining a controlled potential between the N/sub 2/O/sub 4//aqueous HNO/sub 3/ solution and the anode. A potential of about 1.80V vs. SCE is preferred. Anhydrous or aqueous HNO/sub 3/ may be disposed at the cathode within the electrochemical cell. Aqueous HNO/sub 3/ having a water content of up to about 12% by weight is utilized to synthesize anhydrous HNO/sub 3/.

Glass transition of aqueous solutions involving annealing-induced ice recrystallization resolves liquid-liquid transition puzzle of water

PubMed Central

Zhao, Li-Shan; Cao, Ze-Xian; Wang, Qiang

2015-01-01

Liquid-liquid transition of water is an important concept in condensed-matter physics. Recently, it was claimed to have been confirmed in aqueous solutions based on annealing-induced upshift of glass-liquid transition temperature, . Here we report a universal water-content, , dependence of for aqueous solutions. Solutions with vitrify/devitrify at a constant temperature, , referring to freeze-concentrated phase with left behind ice crystallization. Those solutions with totally vitrify at under conventional cooling/heating process though, of the samples annealed at temperatures   to effectively evoke ice recrystallization is stabilized at . Experiments on aqueous glycerol and 1,2,4-butanetriol solutions in literature were repeated, and the same samples subject to other annealing treatments equally reproduce the result. The upshift of by annealing is attributable to freeze-concentrated phase of solutions instead of ‘liquid II phase of water’. Our work also provides a reliable method to determine hydration formula and to scrutinize solute-solvent interaction in solution. PMID:26503911

Physico-chemical properties of aqueous drug solutions: From the basic thermodynamics to the advanced experimental and simulation results.

PubMed

Bellich, Barbara; Gamini, Amelia; Brady, John W; Cesàro, Attilio

2018-04-05

The physical chemical properties of aqueous solutions of model compounds are illustrated in relation to hydration and solubility issues by using three perspectives: thermodynamic, spectroscopic and molecular dynamics simulations. The thermodynamic survey of the fundamental backgrounds of concentration dependence and experimental solubility results show some peculiar behavior of aqueous solutions with several types of similar solutes. Secondly, the use of a variety of experimental spectroscopic devices, operating under different experimental conditions of dimension and frequency, has produced a large amount of structural and dynamic data on aqueous solutions showing the richness of the information produced, depending on where and how the experiment is carried out. Finally, the use of molecular dynamics computational work is presented to highlight how the different types of solute functional groups and surface topologies organize adjacent water molecules differently. The highly valuable contribution of computer simulation studies in providing molecular explanations for experimental deductions, either of a thermodynamic or spectroscopic nature, is shown to have changed the current knowledge of many aqueous solution processes. While this paper is intended to provide a collective view on the latest literature results, still the presentation aims at a tutorial explanation of the potentials of the three methodologies in the field of aqueous solutions of pharmaceutical molecules. Copyright © 2018. Published by Elsevier B.V.

Assorted interactions of amino acids prevailing in aqueous vitamin C solutions probed by physicochemical and ab-initio contrivances

NASA Astrophysics Data System (ADS)

Das, Koyeli; Roy, Milan Chandra; Rajbanshi, Biplab; Roy, Mahendra Nath

2017-11-01

Qualitative and quantitative analysis of molecular interaction prevailing in tyrosine and tryptophan in aqueous solution of vitamin C have been probed by thermophysical properties. The apparent molar volume (ϕV), viscosity B-coefficient, molal refraction (RM) of tyrosine and tryptophan have been studied in aqueous vitamin C solutions at diverse temperatures via Masson equation which deduced solute-solvent and solute-solute interactions, respectively. Spectroscopic study along with physicochemical and computational techniques provides lots of interesting and highly significant insights of the model biological systems. The overall results established strong solute-solvent interactions between studied amino acids and vitamin C mixture in the ternary solutions.

URANIUM DECONTAMINATION WITH RESPECT TO ZIRCONIUM

DOEpatents

Vogler, S.; Beederman, M.

1961-05-01

A process is given for separating uranium values from a nitric acid aqueous solution containing uranyl values, zirconium values and tetravalent plutonium values. The process comprises contacting said solution with a substantially water-immiscible liquid organic solvent containing alkyl phosphate, separating an organic extract phase containing the uranium, zirconium, and tetravalent plutonium values from an aqueous raffinate, contacting said organic extract phase with an aqueous solution 2M to 7M in nitric acid and also containing an oxalate ion-containing substance, and separating a uranium- containing organic raffinate from aqueous zirconium- and plutonium-containing extract phase.

PROCESS OF SEPARATING URANIUM FROM AQUEOUS SOLUTION BY SOLVENT EXTRACTION

DOEpatents

Warf, J.C.

1958-08-19

A process is described for separating uranium values from aqueous uranyl nitrate solutions. The process consists in contacting the uramium bearing solution with an organic solvent, tributyl phosphate, preferably diluted with a less viscous organic liquida whereby the uranyl nitrate is extracted into the organic solvent phase. The uranvl nitrate may be recovered from the solvent phase bv back extracting with an aqueous mediuin.

In Situ Cross-Linking of Polyvinyl Alcohol Films

NASA Technical Reports Server (NTRS)

Philipp, W. H.; Shu, L. C.; May, C. E.

1984-01-01

Films or impregnated matrices readily made from aqueous polyvinyl alcohol solution. Controlled thickness films made by casting precise quantities of aqueous polymer solution on smooth surface, allowing water to evaporate and then removing film. Composite separators formed in similar fashion by impregnating cloth matrix with polyvinyl alcohol solution and drying composite. Insoluble thin hydrophilic membranes made from aqueous systems, and use of undesirable organic solvents not required.

Sediment Ecosystem Assessment Protocol (SEAP): An Accurate and Integrated Weight-of-Evidence Based System

DTIC Science & Technology

2011-01-01

polychaete Neanthes arenaceodentata from exposures to copper in aqueous solutions ...involved 96 h exposures in aqueous solutions , followed by a 1-2 hour (depending on size) feeding period on Artemia (brine shrimp) nauplii in clean seawater...EC50) based on post- exposure feeding of the polychaete Neanthes arenaceodentata from exposures to copper in aqueous solutions . Metric (µg/L) Worm age

Synthesis and Characterization of Functional Mesostructures Using Colloidal Crystal Templating

DTIC Science & Technology

2004-01-01

fluorescent probes in aqueous polymer solutions . Khoury and co-workers measured the diffusion coefficient of several fluorescein-labeled proteins in...diffraction naq refractive index of the aqueous solution phase xvii ni refractive index of component i ngel refractive index of the hydrogel...phase Tg glass transition temperature α angle of diffraction φaq volume fraction of the aqueous solution phase φi volume fraction of

SOLVENT EXTRACTION OF THORIUM VALUES FROM AQUEOUS SOLUTIONS

DOEpatents

Warf, J.C.

1959-04-21

The separation of thorium values from rare earth metals contained ln aqueous solutions by means of extraction with a water immiscible alkyl phosphate diluted with a hydrocarbon such as hexane is described. While the extraction according to this invention may be carried out from any aqueous salt solution, it is preferred to use solutions containing free mineral acid. Hydrochloric acid and in particular nitric acid are sultable in a concentration ranging from 0.1 to 7 normal. The higher acid concentration results in higher extraction values.

Influence of pH, temperature, and concentration on stabilization of aqueous hornet silk solution and fabrication of salt-free materials.

PubMed

Kameda, Tsunenori

2015-01-01

We found that an aqueous solution of silk from cocoons produced by hornet larvae (hornet silk) can be obtained when the solution is adjusted to basic conditions of pH > 9.2. It is known that native hornet cocoons can be dissolved in concentrated aqueous solution of salts, such as lithium bromide (LiBr) and calcium chloride (CaCl2). Upon the removal of these salts from solution by dialysis, solidification, gelation, or sedimentation of hornet silk is known to occur. In the present study, under basic conditions, however, no such solidification occurred, even after salt removal. In this study, ammonia was used for alkalization of solution because it is volatilized during the casting process and pure hornet silk materials can be obtained after drying. The effects of the concentrations of hornet silk and ammonia, as well as dialysis temperature, on preventing gelation during dialysis were investigated. Dialysis conditions that limit the degradation of hornet silk by hydrolysis in alkali solution were identified. Moreover, casting conditions to prepare flexible and transparent hornet silk film from aqueous ammonia solution were optimized. Molecular structural analysis of hornet silk in aqueous ammonia solution and cast film indicated the formation of α-helix conformations. © 2014 Wiley Periodicals, Inc.

Aspheric Solute Ions Modulate Gold Nanoparticle Interactions in an Aqueous Solution: An Optimal Way to Reversibly Concentrate Functionalized Nanoparticles

PubMed Central

Villarreal, Oscar D; Chen, Liao Y; Whetten, Robert L; Demeler, Borries

2015-01-01

Nanometer-sized gold particles (AuNPs) are of peculiar interest because their behaviors in an aqueous solution are sensitive to changes in environmental factors including the size and shape of the solute ions. In order to determine these important characteristics, we performed all-atom molecular dynamics simulations on the icosahedral Au144 nanoparticles each coated with a homogeneous set of 60 thiolates (4-mercapto-benzoate, pMBA) in eight aqueous solutions having ions of varying sizes and shapes (Na+, K+, tetramethylamonium cation TMA+, trisamonium cation TRS+, Cl−, and OH−). For each solution, we computed the reversible work (potential of mean of force) to bring two nanoparticles together as a function of their separation distance. We found that the behavior of pMBA protected Au144 nanoparticles can be readily modulated by tuning their aqueous environmental factors (pH and solute ion combinations). We examined the atomistic details on how the sizes and shapes of solute ions quantitatively factor in the definitive characteristics of nanoparticle-environment and nanoparticle-nanoparticle interactions. We predict that tuning the concentrations of non-spherical composite ions such as TRS+ in an aqueous solution of AuNPs be an effective means to modulate the aggregation propensity desired in biomedical and other applications of small charged nanoparticles. PMID:26581232

Aspheric Solute Ions Modulate Gold Nanoparticle Interactions in an Aqueous Solution: An Optimal Way To Reversibly Concentrate Functionalized Nanoparticles.

PubMed

Villarreal, Oscar D; Chen, Liao Y; Whetten, Robert L; Demeler, Borries

2015-12-17

Nanometer-sized gold particles (AuNPs) are of peculiar interest because their behaviors in an aqueous solution are sensitive to changes in environmental factors including the size and shape of the solute ions. In order to determine these important characteristics, we performed all-atom molecular dynamics simulations on the icosahedral Au144 nanoparticles each coated with a homogeneous set of 60 thiolates (4-mercaptobenzoate, pMBA) in eight aqueous solutions having ions of varying sizes and shapes (Na(+), K(+), tetramethylamonium cation TMA(+), tris-ammonium cation TRS(+), Cl(-), and OH(-)). For each solution, we computed the reversible work (potential of mean of force) to bring two nanoparticles together as a function of their separation distance. We found that the behavior of pMBA protected Au144 nanoparticles can be readily modulated by tuning their aqueous environmental factors (pH and solute ion combinations). We examined the atomistic details on how the sizes and shapes of solute ions quantitatively factor in the definitive characteristics of nanoparticle-environment and nanoparticle-nanoparticle interactions. We predict that tuning the concentrations of nonspherical composite ions such as TRS(+) in an aqueous solution of AuNPs be an effective means to modulate the aggregation propensity desired in biomedical and other applications of small charged nanoparticles.

Modified resins for solid-phase extraction

DOEpatents

Fritz, James S.; Sun, Jeffrey J.

1993-07-27

A process of treating aqueous solutions to remove organic solute contaminants by contacting an aqueous solution containing polar organic solute contaminants with a functionalized polystyrene-divinyl benzene adsorbent resin, with the functionalization of said resin being accomplished by organic hydrophilic groups such as hydroxymethyl, acetyl and cyanomethyl.

Modified resins for solid-phase extraction

DOEpatents

Fritz, James S.; Sun, Jeffrey J.

1991-12-10

A process of treating aqueous solutions to remove organic solute contaminants by contacting an aqueous solution containing polar organic solute contaminants with a functionalized polystyrene-divinyl benzene adsorbent resin, with the functionalization of said resin being accomplished by organic hydrophilic groups such as hydroxymethyl, acetyl and cyanomethyl.

URANIUM RECOVERY PROCESS

DOEpatents

Hyman, H.H.; Dreher, J.L.

1959-07-01

The recovery of uranium from the acidic aqueous metal waste solutions resulting from the bismuth phosphate carrier precipitation of plutonium from solutions of neutron irradiated uranium is described. The waste solutions consist of phosphoric acid, sulfuric acid, and uranium as a uranyl salt, together with salts of the fission products normally associated with neutron irradiated uranium. Generally, the process of the invention involves the partial neutralization of the waste solution with sodium hydroxide, followed by conversion of the solution to a pH 11 by mixing therewith sufficient sodium carbonate. The resultant carbonate-complexed waste is contacted with a titanated silica gel and the adsorbent separated from the aqueous medium. The aqueous solution is then mixed with sufficient acetic acid to bring the pH of the aqueous medium to between 4 and 5, whereby sodium uranyl acetate is precipitated. The precipitate is dissolved in nitric acid and the resulting solution preferably provided with salting out agents. Uranyl nitrate is recovered from the solution by extraction with an ether such as diethyl ether.

Diffusion of aqueous solutions of ionic, zwitterionic, and polar solutes

NASA Astrophysics Data System (ADS)

Teng, Xiaojing; Huang, Qi; Dharmawardhana, Chamila Chathuranga; Ichiye, Toshiko

2018-06-01

The properties of aqueous solutions of ionic, zwitterionic, and polar solutes are of interest to many fields. For instance, one of the many anomalous properties of aqueous solutions is the behavior of water diffusion in different monovalent salt solutions. In addition, solutes can affect the stabilities of macromolecules such as proteins in aqueous solution. Here, the diffusivities of aqueous solutions of sodium chloride, potassium chloride, tri-methylamine oxide (TMAO), urea, and TMAO-urea are examined in molecular dynamics simulations. The decrease in the diffusivity of water with the concentration of simple ions and urea can be described by a simple model in which the water molecules hydrogen bonded to the solutes are considered to diffuse at the same rate as the solutes, while the remainder of the water molecules are considered to be bulk and diffuse at almost the same rate as pure water. On the other hand, the decrease in the diffusivity of water with the concentration of TMAO is apparently affected by a decrease in the diffusion rate of the bulk water molecules in addition to the decrease due to the water molecules hydrogen bonded to TMAO. In other words, TMAO enhances the viscosity of water, while urea barely affects it. Overall, this separation of water molecules into those that are hydrogen bonded to solute and those that are bulk can provide a useful means of understanding the short- and long-range effects of solutes on water.

Method and apparatus for measuring volatile compounds in an aqueous solution

DOEpatents

Gilmore, Tyler J [Pasco, WA; Cantrell, Kirk J [West Richland, WA

2002-07-16

The present invention is an improvement to the method and apparatus for measuring volatile compounds in an aqueous solution. The apparatus is a chamber with sides and two ends, where the first end is closed. The chamber contains a solution volume of the aqueous solution and a gas that is trapped within the first end of the chamber above the solution volume. The gas defines a head space within the chamber above the solution volume. The chamber may also be a cup with the second end. open and facing down and submerged in the aqueous solution so that the gas defines the head space within the cup above the solution volume. The cup can also be entirely submerged in the aqueous solution. The second end of the. chamber may be closed such that the chamber can be used while resting on a flat surface such as a bench. The improvement is a sparger for mixing the gas with the solution volume. The sparger can be a rotating element such as a propeller on a shaft or a cavitating impeller. The sparger can also be a pump and nozzle where the pump is a liquid pump and the nozzle is a liquid spray nozzle open, to the head space for spraying the solution volume into the head space of gas. The pump could also be a gas pump and the nozzle a gas nozzle submerged in the solution volume for spraying the head space gas into the solution volume.

Comparison of cytotoxicity in vitro and irritation in vivo for aqueous and oily solutions of surfactants.

PubMed

Czajkowska-Kośnik, Anna; Wolska, Eliza; Chorążewicz, Juliusz; Sznitowska, Małgorzata

2015-01-01

The in vivo model on rabbit eyes and the in vitro cytotoxicity on fibroblasts were used to compare irritation effect of aqueous and oily (Miglyol 812) solutions of surfactants. Tween 20, Tween 80 and Cremophor EL were tested in different concentrations (0.1, 1 or 5%) and the in vitro test demonstrated that surfactants in oil are less cytotoxic than in aqueous solutions. In the in vivo study, the aqueous solutions of surfactants were characterized as non-irritant while small changes in conjunctiva were observed after application the oily solutions of surfactants and the preparations were classified as slightly irritant, however this effect was similar when Miglyol was applied alone. In conclusion, it is reported that the MTT assay does not correlate well with the Draize scores.

Dielectric study of aqueous solutions of sodium dodecyl sulfate in the frequency span 20 Hz to 2 MHz

NASA Astrophysics Data System (ADS)

Kadve, A. M.; Vankar, H. P.; Rana, V. A.

2017-05-01

Dielectric measurements were carried out for aqueous solutions of Sodium Dodecyl Sulfate (SDS) in the frequency span of 20 Hz to 2 MHz at 300.15 K temperature using precision LCR meter. Also the refractive indices were measured for the solutions at 300.15 K temperature using Abbe's refractometer. The measurements were done for ten different concentrations of SDS in distilled water. Determined values of complex permittivity as a function of frequency were used to evaluate other parameters like loss tangent and electric modulus for the liquid samples. The permittivity at optical frequency were also calculated from the measured refractive indices for the aqueous solutions. The effect of concentration variation of SDS in the aqueous solutions on the determined parameters is discussed.

Effective adsorption and collection of cesium from aqueous solution using graphene oxide grown on porous alumina

NASA Astrophysics Data System (ADS)

Entani, Shiro; Honda, Mitsunori; Shimoyama, Iwao; Li, Songtian; Naramoto, Hiroshi; Yaita, Tsuyoshi; Sakai, Seiji

2018-04-01

Graphene oxide (GO) with a large surface area was synthesized by the direct growth of GO on porous alumina using chemical vapor deposition to study the Cs adsorption mechanism in aqueous solutions. Electronic structure analysis employing in situ near-edge X-ray absorption fine structure spectroscopy and X-ray photoelectron spectroscopy measurements clarifies the Cs atoms bond via oxygen functional groups on GO in the aqueous solution. The Cs adsorption capacity was found to be as high as 650-850 mg g-1, which indicates that the GO/porous alumina acts as an effective adsorbent with high adsorption efficiency for radioactive nuclides in aqueous solutions.

RECOVERY OF PROTACTINIUM FROM AQUEOUS SOLUTIONS

DOEpatents

Elson, R.E.

1959-07-14

The recovery of fluoride complexed protactinium from aqueous acidic solutions by solvent extraction is described. Generally the prccess of the invention com rises mixing an aqueous solution containing protactinium in a complexed form with an organic solvent which is specific for protactinium, such as diisopropyl carbinol, then decomposing the protactinium complex by adjusting the acidity of the aqueous solution to between 0-3 to 0-9 M in hydrogen ion concentration, and introducing a source of aluminum ions in sufficient quantity to establish a concentration of 0.5 to 1.2 M aluminum ion, whereupon decomposition of the protactinium fluoride complex takes place and the protactinium ion is taken up by the organic solvent phase.

Process for recovering pertechnetate ions from an aqueous solution also containing other ions

DOEpatents

Rogers, Robin; Horwitz, E. Philip; Bond, Andrew H.

1997-01-01

A solid/liquid process for the separation and recovery of TcO.sub.4.sup.-1 ions from an aqueous solution is disclosed. The solid support comprises separation particles having surface-bonded poly(ethylene glycol) groups; whereas the aqueous solution from which the TcO.sub.4.sup.-1 ions are separated contains a poly(ethylene glycol) liquid/liquid biphase-forming amount of a dissolved salt. A solid/liquid phase admixture of separation particles containing bound TcO.sub.4.sup.-1 ions in such an aqueous solution that is free from MoO.sub.4.sup.-2 ions is also contemplated, as is a chromatography apparatus containing that solid/liquid phase admixture.

Method for selectively reducing plutonium values by a photochemical process

DOEpatents

Friedman, Horace A.; Toth, Louis M.; Bell, Jimmy T.

1978-01-01

The rate of reduction of Pu(IV) to Pu(III) in nitric acid solution containing a reducing agent is enhanced by exposing the solution to 200-500 nm electromagnetic radiation. Pu values are recovered from an organic extractant solution containing Pu(IV) values and U(VI) values by the method of contacting the extractant solution with an aqueous nitric acid solution in the presence of a reducing agent and exposing the aqueous solution to electromagnetic radiation having a wavelength of 200-500 nm. Under these conditions, Pu values preferentially distribute to the aqueous phase and U values preferentially distribute to the organic phase.

Thermodynamic characteristics of protolytic equilibria of L-serine in aqueous solutions

NASA Astrophysics Data System (ADS)

Kochergina, L. A.; Volkov, A. V.; Khokhlova, E. A.; Krutova, O. N.

2011-05-01

The heat effects of the reaction of aqueous solution of L-serine with aqueous solutions of HNO3 and KOH were determined by calorimetry at temperatures of 288.15, 298.15, and 308.15 K, and ionic strength values of 0.2, 0.5, and 1.0 (background electrolyte, KNO3). Standard thermodynamic characteristics (Δr H o, Δr G o, Δr S o, Δ C {/p o}) of the acid-base reactions in aqueous solutions of L-serine were calculated. The effect of the concentration of background electrolyte and temperature on the heats of dissociation of amino acid was considered. The combustion energy of L-serine by bomb calorimetry in the medium of oxygen was determined. The standard combustion and formation enthalpies of crystalline L-serine were calculated. The heats of dissolution of crystalline L-serine in water and solutions of potassium hydroxide at 298.15 K were measured by direct calorimetry. The standard enthalpies of formation of L-serine and products of its dissociation in aqueous solution were calculated.

Recovery of alkali metal constituents from catalytic coal conversion residues

DOEpatents

Soung, W.Y.

In a coal gasification operation (32) or similar conversion process carried out in the presence of an alkali metal-containing catalyst wherein particles containing alkali metal residues are produced, alkali metal constituents are recovered from the particles by contacting them with water or an aqueous solution to remove water-soluble alkali metal constituents and produce an aqueous solution enriched in said constituents. The aqueous solution thus produced is then contacted with carbon dioxide to precipitate silicon constituents, the pH of the resultant solution is increased, preferably to a value in the range between about 12.5 and about 15.0, and the solution of increased pH is evaporated to increase the alkali metal concentration. The concentrated aqueous solution is then recycled to the conversion process where the alkali metal constituents serve as at least a portion of the alkali metal constituents which comprise the alkali metal-containing catalyst.

Efficient ensemble system based on the copper binding motif for highly sensitive and selective detection of cyanide ions in 100% aqueous solutions by fluorescent and colorimetric changes.

PubMed

Jung, Kwan Ho; Lee, Keun-Hyeung

2015-09-15

A peptide-based ensemble for the detection of cyanide ions in 100% aqueous solutions was designed on the basis of the copper binding motif. 7-Nitro-2,1,3-benzoxadiazole-labeled tripeptide (NBD-SSH, NBD-SerSerHis) formed the ensemble with Cu(2+), leading to a change in the color of the solution from yellow to orange and a complete decrease of fluorescence emission. The ensemble (NBD-SSH-Cu(2+)) sensitively and selectively detected a low concentration of cyanide ions in 100% aqueous solutions by a colorimetric change as well as a fluorescent change. The addition of cyanide ions instantly removed Cu(2+) from the ensemble (NBD-SSH-Cu(2+)) in 100% aqueous solutions, resulting in a color change of the solution from orange to yellow and a "turn-on" fluorescent response. The detection limits for cyanide ions were lower than the maximum allowable level of cyanide ions in drinking water set by the World Health Organization. The peptide-based ensemble system is expected to be a potential and practical way for the detection of submicromolar concentrations of cyanide ions in 100% aqueous solutions.

Process for extracting technetium from alkaline solutions

DOEpatents

Moyer, Bruce A.; Sachleben, Richard A.; Bonnesen, Peter V.

1995-01-01

A process for extracting technetium values from an aqueous alkaline solution containing at least one alkali metal hydroxide and at least one alkali metal nitrate, the at least one alkali metal nitrate having a concentration of from about 0.1 to 6 molar. The solution is contacted with a solvent consisting of a crown ether in a diluent for a period of time sufficient to selectively extract the technetium values from the aqueous alkaline solution. The solvent containing the technetium values is separated from the aqueous alkaline solution and the technetium values are stripped from the solvent.

Bidentate organophosphorus solvent extraction process for actinide recovery and partition

DOEpatents

Schulz, Wallace W.

1976-01-01

A liquid-liquid extraction process for the recovery and partitioning of actinide values from acidic nuclear waste aqueous solutions, the actinide values including trivalent, tetravalent and hexavalent oxidation states is provided and includes the steps of contacting the aqueous solution with a bidentate organophosphorous extractant to extract essentially all of the actinide values into the organic phase. Thereafter the respective actinide fractions are selectively partitioned into separate aqueous solutions by contact with dilute nitric or nitric-hydrofluoric acid solutions. The hexavalent uranium is finally removed from the organic phase by contact with a dilute sodium carbonate solution.

Adsorption of Cu(II) from aqueous solution on sulfuric acid treated palygorskite

NASA Astrophysics Data System (ADS)

Niu, Yan-Ning; Yuan, Yuan; Gao, Wei-Xin; Qian, Sheng; Sun, Wen

2018-03-01

The absorption behavior of Cu2+ from aqueous solution on sulfuric acid treated palygorskite were investigated, the results showed that palygorskite had high absorption ability for Cu2+ from aqueous solution. Effects of the shaking time, pH and the copper ion concentration on the removal rate were discussed. The absorption behavior of Cu2+ could be well imitated by the Langmuir isothermal equation.

Water purification using organic salts

DOEpatents

Currier, Robert P.

2004-11-23

Water purification using organic salts. Feed water is mixed with at least one organic salt at a temperature sufficiently low to form organic salt hydrate crystals and brine. The crystals are separated from the brine, rinsed, and melted to form an aqueous solution of organic salt. Some of the water is removed from the aqueous organic salt solution. The purified water is collected, and the remaining more concentrated aqueous organic salt solution is reused.

Structural and spectroscopic studies of a rare non-oxido V(v) complex crystallized from aqueous solution

DOE PAGES

Leggett, Christina J.; Parker, Bernard F.; Teat, Simon J.; ...

2016-01-14

A “bare” V 5+ complex with glutaroimide-dioxime (H 3L), a ligand for uranium recovery from seawater, was synthesized from aqueous solution as Na[V(L) 2]2H 2O and the structure determined by x-ray diffraction. It is the first non-oxo V(v) complex that has been directly synthesized in and crystallized from aqueous solution.

Measurement of Surface Forces

DTIC Science & Technology

1990-11-16

creating an electrical double-layer whenever a bare mica surface is in contact with an aqueous solution . The mica/electrolyte double-layer...between mica in aqueous solutions containing 10-5 to I M KNO 3 (From Reference 44. Copyright 0 1985 Royal Swedish Academy. Reprinted with permission of...can be observed in aqueous KNO 3 solutions at close separations and at high ion concentrations. For example, if the force curves in Figure 8 (top) for

Structural and spectroscopic studies of a rare non-oxido V(v) complex crystallized from aqueous solution

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

Leggett, Christina J.; Parker, Bernard F.; Teat, Simon J.

A “bare” V 5+ complex with glutaroimide-dioxime (H 3L), a ligand for uranium recovery from seawater, was synthesized from aqueous solution as Na[V(L) 2]2H 2O and the structure determined by x-ray diffraction. It is the first non-oxo V(v) complex that has been directly synthesized in and crystallized from aqueous solution.

Sorption of 4-carboxyquinoline derivatives from aqueous acetonitrile solutions on the surface of porous graphitized carbon

NASA Astrophysics Data System (ADS)

Savchenkova, A. S.; Buryak, A. K.; Kurbatova, S. V.

2015-09-01

The sorption of 4-carboxyquinoline derivatives from aqueous acetonitrile solutions on porous graphitized carbon was studied. The effect of the structure of analyte molecules and the eluent composition on the characteristics of retention under the conditions of RP HPLC was analyzed. The effect of pH of the eluent on the shift of equilibrium in aqueous acetonitrile solutions was investigated.

ADSORPTION PROCEDURE IN PREPARING U$sup 23$$sup 3$

DOEpatents

Stoughton, R.W.

1958-10-14

A process is presented for the separation of protoactinium and thorium from an aqueous nitric acid solution containing these metals. It comprises contacting the solution with a cation exchange phenol-formaldehyde resin containing sulfonic acid groups, and eluting the adsorbed thorium from the resin by means of aqueous nitric acid. Thereafter the adsorbed protoactinium is eluted from the resin by means of an aqueous solution of ammonium fluoride.

KDP Aqueous Solution-in-Oil Microemulsion for Ultra-Precision Chemical-Mechanical Polishing of KDP Crystal

PubMed Central

Dong, Hui; Wang, Lili; Gao, Wei; Li, Xiaoyuan; Wang, Chao; Ji, Fang; Pan, Jinlong; Wang, Baorui

2017-01-01

A novel functional KH2PO4 (KDP) aqueous solution-in-oil (KDP aq/O) microemulsion system for KDP crystal ultra-precision chemical-mechanical polishing (CMP) was prepared. The system, which consisted of decanol, Triton X-100, and KH2PO4 aqueous solution, was available at room temperature. The functional KDP aq/O microemulsion system was systematically studied and applied as polishing solution to KDP CMP technology. In this study, a controlled deliquescent mechanism was proposed for KDP polishing with the KDP aq/O microemulsion. KDP aqueous solution, the chemical etchant in the polishing process, was caged into the micelles in the microemulsion, leading to a limitation of the reaction between the KDP crystal and KDP aqueous solution only if the microemulsion was deformed under the effect of the external force. Based on the interface reaction dynamics, KDP aqueous solutions with different concentrations (cKDP) were applied to replace water in the traditional water-in-oil (W/O) microemulsion. The practicability of the controlled deliquescent mechanism was proved by the decreasing material removal rate (MRR) with the increasing of the cKDP. As a result, the corrosion pits on the KDP surface were avoided to some degree. Moreover, the roughnesses of KDP with KDP aq/O microemulsion (cKDP was changed from 10 mM to 100 mM) as polishing solutions were smaller than that with the W/O microemulsion. The smallest surface root-mean-square roughness of 1.5 nm was obtained at a 30 mmol/L KDP aq solution, because of the most appropriate deliquescent rate and MRR. PMID:28772632

KDP Aqueous Solution-in-Oil Microemulsion for Ultra-Precision Chemical-Mechanical Polishing of KDP Crystal.

PubMed

Dong, Hui; Wang, Lili; Gao, Wei; Li, Xiaoyuan; Wang, Chao; Ji, Fang; Pan, Jinlong; Wang, Baorui

2017-03-09

A novel functional KH₂PO₄ (KDP) aqueous solution-in-oil (KDP aq/O) microemulsion system for KDP crystal ultra-precision chemical-mechanical polishing (CMP) was prepared. The system, which consisted of decanol, Triton X-100, and KH₂PO₄ aqueous solution, was available at room temperature. The functional KDP aq/O microemulsion system was systematically studied and applied as polishing solution to KDP CMP technology. In this study, a controlled deliquescent mechanism was proposed for KDP polishing with the KDP aq/O microemulsion. KDP aqueous solution, the chemical etchant in the polishing process, was caged into the micelles in the microemulsion, leading to a limitation of the reaction between the KDP crystal and KDP aqueous solution only if the microemulsion was deformed under the effect of the external force. Based on the interface reaction dynamics, KDP aqueous solutions with different concentrations ( c KDP ) were applied to replace water in the traditional water-in-oil (W/O) microemulsion. The practicability of the controlled deliquescent mechanism was proved by the decreasing material removal rate (MRR) with the increasing of the c KDP . As a result, the corrosion pits on the KDP surface were avoided to some degree. Moreover, the roughnesses of KDP with KDP aq/O microemulsion ( c KDP was changed from 10 mM to 100 mM) as polishing solutions were smaller than that with the W/O microemulsion. The smallest surface root-mean-square roughness of 1.5 nm was obtained at a 30 mmol/L KDP aq solution, because of the most appropriate deliquescent rate and MRR.

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.

Ceramic porous material and method of making same

DOEpatents

Liu, Jun; Kim, Anthony Y.; Virden, Jud W.

1997-01-01

The invention is a mesoporous ceramic membrane having substantially uniform pore size. Additionally, the invention includes aqueous and non-aqueous processing routes to making the mesoporous ceramic membranes. According to one aspect of the present invention, inserting a substrate into a reaction chamber at pressure results in reaction products collecting on the substrate and forming a membrane thereon. According to another aspect of the present invention, a second aqueous solution that is sufficiently immiscible in the aqueous solution provides an interface between the two solutions whereon the mesoporous membrane is formed. According to a further aspect of the present invention, a porous substrate is placed at the interface between the two solutions permitting formation of a membrane on the surface or within the pores of the porous substrate. According to yet another aspect of the present invention, mesoporous ceramic materials are formed using a non-aqueous solvent and water-sensitive precursors.

Ceramic porous material and method of making same

DOEpatents

Liu, J.; Kim, A.Y.; Virden, J.W.

1997-07-08

The invention is a mesoporous ceramic membrane having substantially uniform pore size. Additionally, the invention includes aqueous and non-aqueous processing routes to making the mesoporous ceramic membranes. According to one aspect of the present invention, inserting a substrate into a reaction chamber at pressure results in reaction products collecting on the substrate and forming a membrane thereon. According to another aspect of the present invention, a second aqueous solution that is sufficiently immiscible in the aqueous solution provides an interface between the two solutions whereon the mesoporous membrane is formed. According to a further aspect of the present invention, a porous substrate is placed at the interface between the two solutions permitting formation of a membrane on the surface or within the pores of the porous substrate. According to yet another aspect of the present invention, mesoporous ceramic materials are formed using a non-aqueous solvent and water-sensitive precursors. 21 figs.

Antiscalant properties of Spergularia rubra and Parietaria officinalis aqueous solutions

NASA Astrophysics Data System (ADS)

Cheap-Charpentier, Hélène; Gelus, Dominique; Pécoul, Nathalie; Perrot, Hubert; Lédion, Jean; Horner, Olivier; Sadoun, Jonathan; Cachet, Xavier; Litaudon, Marc; Roussi, Fanny

2016-06-01

The formation of calcium carbonate in water has important implications in industry. Chemical antiscalant is usually used to control scale depositions. Plant extracts have been recently used as new green antiscalant agents, as they can be easily prepared and are environmentally friendly. In this study, stock aqueous solutions of Spergularia rubra and Parietaria officinalis, two plants used in traditional medicine to treat or prevent urolithiasis, were obtained by infusion. The antiscaling properties of these extracts towards CaCO3 formation were tested by using chronoamperometry and Fast Controlled Precipitation methods. The aqueous solution of S. rubra was further fractionated to isolate compounds of lower polarity. Their efficiency towards CaCO3 precipitation was characterized by Fast Controlled Precipitation method. The inhibiting efficiency of this fractionated solution was greater than that of the stock aqueous solution.

SEPARATION PROCESS FOR TRANSURANIC ELEMENT AND COMPOUNDS THEREOF

DOEpatents

Magnusson, L.B.

1958-04-01

A process is described for the separation of neptunium, from aqueous solutions of neptunium, plutonium, uraniunn, and fission prcducts. This separation from an acidic aqueous solution of a tetravalent neptuniunn can be made by contacting the solution with a certain type of chelating,; agent, preferably dissolved in an organic solvent, to form a neptunium chelate compound. When the organic solvent is present, the neptunium chelate compound is extracted; otherwise, it precipitates from the aqueous solution and is separated by any suitable means. The chelating agent is a fluorinated BETA -diketone. such as trifluoroacetyl acetone.

Radiolysis of aqueous solutions of thiamine

NASA Astrophysics Data System (ADS)

Chijate, C.; Albarran, G.; Negron-Mendoza, A.

1998-06-01

The results of the radiolysis of aqueous solutions of thiamine (vitamin B 1) are presented. The yields for decomposition of thiamine and the product of radiolytic products were determined. The G values decrease as the dose increases. Some radiolytic products were identified. Decomposition of thiamine was slightly dependent on the presence of oxygen and on the pH of the solution. At pH 4.4 with a concentration of 2.5 × 10 -4 mol L -1 of thiamine in an oxygen free aqueous solution, the G 0 value for decomposition is 5.0.

ION EXCHANGE PROCESS FOR THE RECOVERY AND PURIFICATION OF MATERIALS

DOEpatents

Long, R.S.; Bailes, R.H.

1958-04-15

A process for the recovery of certain metallic ions from aqueous solutions by ion exchange techniques is described. It is applicable to elements such as vanadium, chromium, nnanganese, and the like, which are capable of forming lower valent cations soluble in aqueous solutions and which also form ldgher valent anions soluble in aqueous acidic solutions. For example, small amounts of vanadium occurring in phosphoric acid prepared from phosphate rock may be recovered by reducing the vanadium to a trivalent cation adsorbing; the vanadium in a cationic exchange resin, then treating the resin with a suitable oxidizing agent to convert the adsorbed vanadium to a higher valent state, and finally eluting; the vanadium as an anion from the resin by means of an aqueous acidic solution.

Removal of copper ions from aqueous solutions by a steel-making by-product.

PubMed

López, F A; Martín, M I; Pérez, C; López-Delgado, A; Alguacil, F J

2003-09-01

A study is made of the use of a steel-making by-product (rolling mill scale) as a material for removing Cu(2+) ions from aqueous solutions. The influence of contact time, initial copper ion concentration and temperature on removal capability is considered. The removal of Cu(2+) ions from an aqueous solution involves two processes: on the one hand, the adsorption of Cu(2+) ions on the surface of mill scale due to the iron oxides present in the latter; and on the other hand, the cementation of Cu(2+) onto metallic iron contained in the mill scale. Rolling mill scale is seen to be an effective material for the removal of copper ions from aqueous solutions.

Process for recovering pertechnetate ions from an aqueous solution also containing other ions

DOEpatents

Rogers, R.; Horwitz, E.P.; Bond, A.H.

1997-02-18

A solid/liquid process for the separation and recovery of TcO{sub 4}{sup {minus}1} ions from an aqueous solution is disclosed. The solid support comprises separation particles having surface-bonded poly(ethylene glycol) groups; whereas the aqueous solution from which the TcO{sub 4}{sup {minus}1} ions are separated contains a poly(ethylene glycol) liquid/liquid biphase-forming amount of a dissolved salt. A solid/liquid phase admixture of separation particles containing bound TcO{sub 4}{sup {minus}1} ions in such an aqueous solution that is free from MoO{sub 4}{sup {minus}2} ions is also contemplated, as is a chromatography apparatus containing that solid/liquid phase admixture. 15 figs.

Supercooling of aqueous dimethylsulfoxide solution at normal and high pressures: Evidence for the coexistence of phase-separated aqueous dimethylsulfoxide solutions of different water structures.

PubMed

Kanno, H; Kajiwara, K; Miyata, K

2010-05-21

Supercooling behavior of aqueous dimethylsulfoxide (DMSO) solution was investigated as a function of DMSO concentration and at high pressures. A linear relationship was observed for T(H) (homogeneous ice nucleation temperature) and T(m) (melting temperature) for the supercooling of aqueous DMSO solution at normal pressure. Analysis of the DTA (differential thermal analysis) traces for homogeneous ice crystallization in the bottom region of the T(H) curve for a DMSO solution of R=20 (R: moles of water/moles of DMSO) at high pressures supported the contention that the second critical point (SCP) of liquid water should exist at P(c2)= approximately 200 MPa and at T(c2)<-100 degrees C (P(c2): pressure of SCP, T(c2): temperature of SCP). The presence of two T(H) peaks for DMSO solutions (R=15, 12, and 10) suggests that phase separation occurs in aqueous DMSO solution (R

Supercooling of aqueous dimethylsulfoxide solution at normal and high pressures: Evidence for the coexistence of phase-separated aqueous dimethylsulfoxide solutions of different water structures

NASA Astrophysics Data System (ADS)

Kanno, H.; Kajiwara, K.; Miyata, K.

2010-05-01

Supercooling behavior of aqueous dimethylsulfoxide (DMSO) solution was investigated as a function of DMSO concentration and at high pressures. A linear relationship was observed for TH (homogeneous ice nucleation temperature) and Tm (melting temperature) for the supercooling of aqueous DMSO solution at normal pressure. Analysis of the DTA (differential thermal analysis) traces for homogeneous ice crystallization in the bottom region of the TH curve for a DMSO solution of R =20 (R: moles of water/moles of DMSO) at high pressures supported the contention that the second critical point (SCP) of liquid water should exist at Pc2=˜200 MPa and at Tc2<-100 °C (Pc2: pressure of SCP, Tc2: temperature of SCP). The presence of two TH peaks for DMSO solutions (R =15, 12, and 10) suggests that phase separation occurs in aqueous DMSO solution (R ≤15) at high pressures and low temperatures (<-90 °C). The pressure dependence of the two TH curves for DMSO solutions of R =10 and 12 indicates that the two phase-separated components in the DMSO solution of R =10 have different liquid water structures [LDL-like and HDL-like structures (LDL: low-density liquid water, HDL: high-density liquid water)] in the pressure range of 120-230 MPa.

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.

PROCESS FOR SEPARATING PLUTONIUM BY REPEATED PRECIPITATION WITH AMPHOTERIC HYDROXIDE CARRIERS

DOEpatents

Faris, B.F.

1960-04-01

A multiple carrier precipitation method is described for separating and recovering plutonium from an aqueous solution. The hydroxide of an amphoteric metal is precipitated in an aqueous plutonium-containing solution. This precipitate, which carries plutonium, is then separated from the supernatant liquid and dissolved in an aqueous hydroxide solution, forming a second plutonium- containing solution. lons of an amphoteric metal which forms an insoluble hydroxide under the conditions existing in this second solution are added to the second solution. The precipitate which forms and which carries plutonium is separated from the supernatant liquid. Amphoteric metals which may be employed are aluminum, bibmuth, copper, cobalt, iron, lanthanum, nickel, and zirconium.

Mechanistic roles of soil humus and minerals in the sorption of nonionic organic compounds from aqueous and organic solutions

USGS Publications Warehouse

Chiou, C.T.; Shoup, T.D.; Porter, P.E.

1985-01-01

Mechanistic roles of soil humus and soil minerals and their contributions to soil sorption of nonionic organic compounds from aqueous and organic solutions are illustrated. Parathion and lindane are used as model solutes on two soils that differ greatly in their humic and mineral contents. In aqueous systems, observed sorptive characteristics suggest that solute partitioning into the soil-humic phase is the primary mechanism of soil uptake. By contrast, data obtained from organic solutions on dehydrated soil partitioning into humic phase and adsorption by soil minerals is influenced by the soil-moisture content and by the solvent medium from which the solute is sorbed. ?? 1985.

How Does a Hydrophobic Macromolecule Respond to Mixed Osmolyte Environment?

PubMed

Tah, Indrajit; Mondal, Jagannath

2016-10-04

The role of the protecting osmolyte Trimethyl N-oxide (TMAO) in counteracting the denaturing effect of urea on a protein is quite well established. However, the mechanistic role of osmolytes on the hydrophobic interaction underlying protein folding is a topic of contention and is emerging as a key area of biophysical interest. Although recent experiment and computer simulation have established that individual aqueous solution of TMAO and urea respectively stabilizes and destabilizes the collapsed conformation of a hydrophobic polymer, it remains to be explored how a mixed aqueous solution of protecting and denaturing osmolytes influences the conformations of the polymer. In order to bridge the gap, we have simulated the conformational behavior of both a model hydrophobic polymer and a synthetic polymer polystyrene in an aqueous mixture of TMAO and urea. Intriguingly, our free energy based simulations on both the systems show that even though a pure aqueous solution of TMAO stabilizes the collapsed or globular conformation of the hydrophobic polymer, addition of TMAO to an aqueous solution of urea further destabilizes the collapsed conformation of the hydrophobic polymer. We also observe that the extent of destabilization in a mixed osmolyte solution is relatively higher than that in pure aqueous urea solution. The reinforcement of the denaturation effect of the hydrophobic macromolecule in a mixed osmolyte solution is in stark contrast to the well-known counteracting role of TMAO in proteins under denaturing condition of urea. In both model and realistic systems, our results show that in a mixed aqueous solution, greater number of cosolutes preferentially bind to the extended conformation of the polymer relative to that in the collapsed conformation, thereby complying with Tanford-Wyman preferential solvation theory disfavoring the collapsed conformation. The results are robust across a range of osmolyte concentrations and multiple cosolute forcefields. Our findings unequivocally imply that the action of mixed osmolyte solution on hydrophobic polymer is significantly distinct from that of proteins.

Simple introduction of carboxyl head group with alkyl spacer onto multiwalled carbon nanotubes by solution plasma process

NASA Astrophysics Data System (ADS)

Nemoto, Shimpei; Ueno, Tomonaga; Watthanaphanit, Anyarat; Hieda, Junko; Bratescu, Maria Antoaneta; Saito, Nagahiro

2017-09-01

A simple method of fabricating carboxyl-terminated multiwalled carbon nanotubes (MWCNTs) with alkyl spacers was developed to improve the dispersion quality of MWCNTs in aqueous solutions using solution plasma (SP) in a 6-aminocaproic acid solution. The formation of SP in the solution led to better dispersion of MWCNTs in aqueous solutions. Fourier transform infrared spectroscopy (FT-IR) results indicate that a carboxyl group with an alkyl spacer can be introduced by SP treatment in the 6-aminocaproic acid solution. Sedimentation tests show that the SP-treated MWCNTs in the 6-aminocaproic acid solution retained their good dispersion quality in aqueous solutions of pHs 5, 6, and 9. The alkyl spacer plays an important role in the preservation of dispersion states particularly at pH 6.

Aqueous penetration and biological activity of moxifloxacin 0.5% ophthalmic solution and gatifloxacin 0.3% solution in cataract surgery patients.

PubMed

Kim, Dianne H; Stark, Walter J; O'Brien, Terrence P; Dick, James D

2005-11-01

To measure the achievable perioperative aqueous concentration of the commercially available topically administered fourth generation fluoroquinolones, moxifloxacin 0.5% ophthalmic solution, and gatifloxacin 0.3% ophthalmic solution, and to correlate this concentration with the agents' biological efficacy in the aqueous humor of patients undergoing routine cataract surgery. Prospective, randomized, parallel, double-masked, clinical trial. Fifty patients undergoing cataract extraction. Patients (n = 25) were given perioperative topical moxifloxacin 0.5% or topical gatifloxacin 0.3% (n = 25). One drop of antibiotic was administered every 10 minutes for 4 doses beginning 1 hour prior to surgery. Aqueous humor was sampled via paracentesis and antibiotic concentrations were determined using validated high performance liquid chromatography (HPLC) procedures. Dilution analyses were performed to determine the biological efficacy of the agents in the aqueous against Staphylococcus epidermidis, the most common cause of postcataract endophthalmitis. Aqueous humor antibiotic concentrations were measured using HPLC and microdilution bioassay techniques. Biological activity was measured as minimal inhibitory dilution and minimal bactericidal dilution. Aqueous humor concentrations for moxifloxacin via HPLC analysis were 1.80 (+/-1.21) microg/ml, whereas those for gatifloxacin were 0.48 (+/-0.34) microg/ml. This 3.8-fold difference in aqueous humor antibiotic concentrations was statistically significant (P = 0.00003). Similarly, the biological dilution analysis of the aqueous humor samples showed that moxifloxacin attained an estimated activity of 2.1 microg/ml, whereas the gatifloxacin activity was approximately 0.4 mug/ml, which represented a 4.9-fold difference. This study demonstrated that after topically administered perioperative antibiotics with cataract surgery, moxifloxacin 0.5% ophthalmic solution achieved a statistically significantly higher concentration in aqueous humor compared with gatifloxacin (P = 0.00003). Results from the broth dilution analysis showed that moxifloxacin 0.5% was biologically more active against S. epidermidis than gatifloxacin 0.3% in aqueous humor after topical application. There were no adverse events reported, and incision wounds healed quickly and as expected.

Electromarking solution

DOEpatents

Bullock, Jonathan S.; Harper, William L.; Peck, Charles G.

1976-06-22

This invention is directed to an aqueous halogen-free electromarking solution which possesses the capacity for marking a broad spectrum of metals and alloys selected from different classes. The aqueous solution comprises basically the nitrate salt of an amphoteric metal, a chelating agent, and a corrosion-inhibiting agent.

SEPARATION OF TECHNETIUM FROM AQUEOUS SOLUTIONS BY COPRECIPITATION WITH MAGNETITE

DOEpatents

Rimshaw, S.J.

1961-10-24

A method of separating technetium in the 4+ oxidation state from an aqueous basic solution containing products of uranium fission is described. The method consists of contacting the solution with finely divided magnetite and recovering a technetium-bearing precipitate. (AEC)

Ice growth from supercooled aqueous solutions of benzene, naphthalene, and phenanthrene.

PubMed

Liyana-Arachchi, Thilanga P; Valsaraj, Kalliat T; Hung, Francisco R

2012-08-23

Classical molecular dynamics (MD) were performed to investigate the growth of ice from supercooled aqueous solutions of benzene, naphthalene, or phenanthrene. The main objective of this study is to explore the fate of those aromatic molecules after freezing of the supercooled aqueous solutions, i.e., if these molecules become trapped inside the ice lattice or if they are displaced to the QLL or to the interface with air. Ice growth from supercooled aqueous solutions of benzene, naphthalene, or phenanthrene result in the formation of quasi-liquid layers (QLLs) at the air/ice interface that are thicker than those observed when pure supercooled water freezes. Naphthalene and phenanthrene molecules in the supercooled aqueous solutions are displaced to the air/ice interface during the freezing process at both 270 and 260 K; no incorporation of these aromatics into the ice lattice is observed throughout the freezing process. Similar trends were observed during freezing of supercooled aqueous solutions of benzene at 270 K. In contrast, a fraction of the benzene molecules become trapped inside the ice lattice during the freezing process at 260 K, with the rest of the benzene molecules being displaced to the air/ice interface. These results suggest that the size of the aromatic molecule in the supercooled aqueous solution is an important parameter in determining whether these molecules become trapped inside the ice crystals. Finally, we also report potential of mean force (PMF) calculations aimed at studying the adsorption of gas-phase benzene and phenanthrene on atmospheric air/ice interfaces. Our PMF calculations indicate the presence of deep free energy minima for both benzene and phenanthrene at the air/ice interface, with these molecules adopting a flat orientation at the air/ice interface.

Polymer-assisted aqueous deposition of metal oxide films

DOEpatents

Li, DeQuan [Los Alamos, NM; Jia, Quanxi [Los Alamos, NM

2003-07-08

An organic solvent-free process for deposition of metal oxide thin films is presented. The process includes aqueous solutions of necessary metal precursors and an aqueous solution of a water-soluble polymer. After a coating operation, the resultant coating is fired at high temperatures to yield optical quality metal oxide thin films.

Recovering oil by injecting aqueous alkali, cosurfactant and gas

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

Reisberg, J.; Bielmowicz, L. J.; Thigpen, D. R.

1985-01-15

A process of recovering oil from a subterranean reservoir in which the oil is acidic but forms monovalent cation soaps of only relatively low interfacial activity when reacted with aqueous alkaline solutions, comprises displacing the oil toward a production location with a mixture of gas and cosurfactant-containing aqueous alkaline solution.

Membrane Treatment of Aqueous Film Forming Foam (AFFF) Wastes for Recovery of Its Active Ingredients

DTIC Science & Technology

1980-10-01

T ME1MBRANE TREATMENT OF AQUEOUS FILM FORMING FOAM~ (AFFF) WASTES FOR RECOVERY OFI Fts ACTIVE INGREDIENTS FINAL REPORT October 1980 by Edward S. K...OF THIS PAGEOPMn Date AVntr* d)__ ---- Ultrafiltration (UF) and Reverse Osmosis (RO) treatment of Aqueous Film Forming Foam (AFFF) solutions was...of Aqueous Film Forming Foam (AFFF) solutions was investigated to determine the feasibility of employing membrane processes to separate and recover

Method for producing oxygen from lunar materials

NASA Technical Reports Server (NTRS)

Sullivan, Thomas A. (Inventor)

1993-01-01

This invention is related to producing oxygen from lunar or Martian materials, particularly from lunar ilmenite in situ. The process includes producing a slurry of the minerals and hot sulfuric acid, the acid and minerals reacting to form sulfates of the metal. Water is added to the slurry to dissolve the minerals into an aqueous solution, the first aqueous solution is separated from unreacted minerals from the slurry, and the aqueous solution is electrolyzed to produce the metal and oxygen.

A fluorescent sensor for selective detection of cyanide using mesoporous graphitic carbon(IV) nitride.

PubMed

Lee, Eun Zoo; Lee, Sun Uk; Heo, Nam-Su; Stucky, Galen D; Jun, Young-Si; Hong, Won Hi

2012-04-25

A turn-on fluorescence sensor, Cu(2+)-c-mpg-C(3)N(4), was developed for detection of CN(-) in aqueous solution by simply mixing cubic mesoporous graphitic carbon nitride (c-mpg-C(3)N(4)) and aqueous solution of Cu(NO(3))(2). The highly sensitive detection of CN(-) with a detection limit of 80 nM is not only possible in aqueous solution but also in human blood serum.

Stiffness-independent highly efficient on-chip extraction of cell-laden hydrogel microcapsules from oil emulsion into aqueous solution by dielectrophoresis

PubMed Central

Huang, Haishui; Sun, Mingrui; Heisler-Taylor, Tyler; Kiourti, Asimina; Volakis, John; Lafyatis, Gregory

2015-01-01

A dielectrophoresis (DEP)-based method is reported to achieve highly efficient on-chip extraction of cell-laden microcapsules of any stiffness from oil into aqueous solution. The hydrogel microcapsules can be extracted into the aqueous solution by DEP and interfacial tension (IFT) forces with no trapped oil while the encapsulated cells are free from the electrical damages due to the Faraday cage effect. PMID:26297051

SALICYLATE PROCESS FOR THORIUM SEPARATION FROM RARE EARTHS

DOEpatents

Cowan, G.A.

1959-08-25

The separation of thorium from rare earths is accomplished by forming an aqueous solution of salts of thorium and rare earths and sufficient acetate buffer to provide a pH of between 2 and 5, adding an ammonium salicylate to the aqueous buffered solution, contacting the resultant solution with a substantially water-immiscible organic solvent mixture of an ether and an ester, and separating the solvent extract phase containing thorium salicylate from the aqueous phase containing the rare earths.

Stability of GO Modified by Different Dispersants in Cement Paste and Its Related Mechanism.

PubMed

Long, Wu-Jian; Fang, Changle; Wei, Jingjie; Li, Haodao

2018-05-18

Graphene oxide (GO) is a potential material to be used as a nano-reinforcement in cement matrix. However, a prerequisite for GO to fulfill its function in the cement matrix is homogeneous dispersion. In this study, the effects of three different dispersing agents (DAs), including polycarboxylate-based high range water reducer (P-HRWR), naphthalene-based high range water reducer (N-HRWR), and air entraining agent (AEA) on the dispersion of GO in aqueous solution, simulated concrete pore solution (SCPS), and suspension of cement pastes were sequentially investigated. Results showed that the dispersion effect of GO in aqueous solutions was improved with different DAs. However, the homogeneous dispersion of GO in aqueous solution re-agglomerated in SCPS and suspension of cement pastes. It was concluded that as the cement content and pH of aqueous solutions increased, GOs re-agglomerated and precipitated in an alkaline solution. A possible mechanism was proposed in this study and it was believed that electrostatic interactions and steric hindrance provided by the P-HRWR further made GOs stable in aqueous solutions. The ions and pH of cement pastes increased with the increasing amount of cement, which caused the separation of P-HRWR from GOs. Therefore, GOs were re-agglomerated and absorbed on the surface of the cement particles, resulting in GOs sedimentation.

Adsorption of arsenic from aqueous solution using magnetic graphene oxide

NASA Astrophysics Data System (ADS)

Sherlala, A. I. A.; Raman, A. A.; Bello, M. M.

2017-06-01

A binary of graphene oxide (GO) and iron oxide (IO) was prepared and used for the removal of arsenic from aqueous solution. The synthesized compound was characterized using XRD analysis. The prepared composite was used for the adsorption of arsenic from aqueous solution. Central Composite Design was used to design the adsorption experiments and to investigate the effects of operational parameters (initial concentration of arsenic, adsorbent dosage, pH and time) on the adsorption capacity and efficiency. The adsorbent shows a high adsorption capacity for the arsenic. The adsorption efficiency ranges between 33.2 % and 99.95 %. The most significant factors affecting the adsorption capacity were found to be the initial concentration of arsenic and the adsorbent dosage. The initial pH of the solution slightly affects the adsorption capacity, with the maximum adsorption capacity occurring around pH 6 - 7. Thus, the developed adsorbent has a potential for effective removal of arsenic from aqueous solution.

Defining microchannels and valves on a hydrophobic paper by low-cost inkjet printing of aqueous or weak organic solutions.

PubMed

Cai, Longfei; Zhong, Minghua; Li, Huolin; Xu, Chunxiu; Yuan, Biyu

2015-07-01

We describe a simple and cost-effective strategy for rapid fabrication of microfluidic paper-based analytical devices and valves by inkjet printing. NaOH aqueous solution was printed onto a hydrophobic filter paper, which was previously obtained by soaking in a trimethoxyoctadecylsilane-heptane solution, allowing selective wet etching of hydrophobic cellulose to create hydrophilic-hydrophobic contrast with a relatively good resolution. Hexadecyltrimethylammonium bromide (CTMAB)-ethanol solution was printed onto hydrophobic paper to fabricate temperature-controlled valves. At low temperature, CTMAB deposited on the paper is insoluble in aqueous fluid, thus the paper remains hydrophobic. At high temperature, CTMAB becomes soluble so the CTMAB-deposited channel becomes hydrophilic, allowing the wicking of aqueous solution through the valve. We believe that this strategy will be very attractive for the development of simple micro analytical devices for point-of-care applications, including diagnostic testing, food safety control, and environmental monitoring.

Adsorptive removal of antibiotics from aqueous solution using carbon materials.

PubMed

Yu, Fei; Li, Yong; Han, Sheng; Ma, Jie

2016-06-01

Antibiotics, an important type of environmental contamination, have attracted many researchers to the study of their removal from aqueous solutions. Adsorption technology is a fast, efficient, and economical physicochemical method that is extensively used in wastewater treatment. From original activated carbon and carbon nanotubes to the latest graphene-based materials, carbon-based materials have been widely used as highly effective adsorbents for contaminant removal from aqueous solution because of their large specific surface area, high porosity, and high reaction activity. In this article, adsorption removal methods for four major types of antibiotic (tetracyclines, sulfonamides, macrolides, and quinolones) are reviewed. We also provide an overview of the application development of carbon materials as adsorbents for antibiotic removal from aqueous solution. The most promising works are discussed, and the main challenges in preparing high-performance adsorbents and the development tendency of adsorbents are also analyzed. This work provides theoretical guidance for subsequent research in the design and modification of carbon materials for applications in the adsorption removal of antibiotics from aqueous solution. Copyright © 2016 Elsevier Ltd. All rights reserved.

Removal of chromium(III) from aqueous waste solution by liquid-liquid extraction in a circular microchannel.

PubMed

Luo, Jian Hong; Li, Jun; Guo, Lei; Zhu, Xin Hua; Dai, Shuang; Li, Xing

2017-11-01

A new circular microchannel device has been proposed for the removal of chromium(III) from aqueous waste solution by using kerosene as a diluent and (2-ethylhexyl) 2-ethylhexyl phosphonate as an extractant. The proposed device has several advantages such as a flexible and easily adaptable design, easy maintenance, and cheap setup without the requirement of microfabrication. To study the extraction efficiency and advantages of the circular microchannel device in the removal of chromium(III), the effects of various operating conditions such as the inner diameter of the channel, the total flow velocity, the phase ratio, the initial pH of aqueous waste solution, the reaction temperature and the initial concentration of extractant on the extraction efficiency are investigated and the optimal process conditions are obtained. The results show that chromium(III) in aqueous waste solution can be effectively removed with (2-ethylhexyl) 2-ethylhexyl phosphonate in the circular microchannel. Under optimized conditions, an extraction efficiency of chromium(III) of more than 99% can be attained and the aqueous waste solution can be discharged directly, which can meet the Chinese national emission standards.

Thermodynamic and structure-property study of liquid-vapor equilibrium for aroma compounds.

PubMed

Tromelin, Anne; Andriot, Isabelle; Kopjar, Mirela; Guichard, Elisabeth

2010-04-14

Thermodynamic parameters (T, DeltaH degrees , DeltaS degrees , K) were collected from the literature and/or calculated for five esters, four ketones, two aldehydes, and three alcohols, pure compounds and compounds in aqueous solution. Examination of correlations between these parameters and the range values of DeltaH degrees and DeltaS degrees puts forward the key roles of enthalpy for vaporization of pure compounds and of entropy in liquid-vapor equilibrium of compounds in aqueous solution. A structure-property relationship (SPR) study was performed using molecular descriptors on aroma compounds to better understand their vaporization behavior. In addition to the role of polarity for vapor-liquid equilibrium of compounds in aqueous solution, the structure-property study points out the role of chain length and branching, illustrated by the correlation between the connectivity index CHI-V-1 and the difference between T and log K for vaporization of pure compounds and compounds in aqueous solution. Moreover, examination of the esters' enthalpy values allowed a probable conformation adopted by ethyl octanoate in aqueous solution to be proposed.

Surface tensions of inorganic multicomponent aqueous electrolyte solutions and melts.

PubMed

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

2010-11-25

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

REMOVAL OF CESIUM BY SORPTION FROM AQUEOUS SOLUTIONS

DOEpatents

Ames, L.L.

1962-01-16

ABS>A process is given for selectively removing cesium from acid aqueous solutions containing cesium in microquantities and other cations in macroquantities by absorption on clinoptilolite. The cesium can be eluted from the clinoptilolite with a solution of ammonia, potassium hydroxide, or rubidium hydroxide. (AEC)

EXTRACTION METHOD FOR SEPARATING URANIUM, PLUTONIUM, AND FISSION PRODUCTS FROM COMPOSITIONS CONTAINING SAME

DOEpatents

Seaborg, G.T.

1957-10-29

Methods for separating plutonium from the fission products present in masses of neutron irradiated uranium are reported. The neutron irradiated uranium is first dissolved in an aqueous solution of nitric acid. The plutonium in this solution is present as plutonous nitrate. The aqueous solution is then agitated with an organic solvent, which is not miscible with water, such as diethyl ether. The ether extracts 90% of the uraryl nitrate leaving, substantially all of the plutonium in the aqueous phase. The aqueous solution of plutonous nitrate is then oxidized to the hexavalent state, and agitated with diethyl ether again. In the ether phase there is then obtained 90% of plutonium as a solution of plutonyl nitrate. The ether solution of plutonyl nitrate is then agitated with water containing a reducing agent such as sulfur dioxide, and the plutonium dissolves in the water and is reduced to the plutonous state. The uranyl nitrate remains in the ether. The plutonous nitrate in the water may be recovered by precipitation.

The relative viscosity of NaNO 3 and NaNO 2 aqueous solutions

DOE PAGES

Reynolds, Jacob G.; Mauss, Billie M.; Daniel, Richard C.

2018-05-09

In aqueous solution, both nitrate and nitrite are planar, monovalent, and have the same elements but different sizes and charge densities. Comparing the viscosity of NaNO 2 and NaNO 3 aqueous solutions provides an opportunity to determine the relative importance of anion size versus strength of anion interaction with water. The viscosity of aqueous NaNO 2 and NaNO 3 were measured over a temperature and concentration range relevant to nuclear waste processing. The viscosity of NaNO 2 solutions was consistently larger than NaNO 3 under all conditions, even though nitrate is larger than nitrite. This was interpreted in terms ofmore » quantum mechanical charge field molecular dynamics calculations that indicate that nitrite forms more and stronger hydrogen bonds with water per oxygen atom than nitrate. Furthermore, these hydrogen bonds inhibit rotational motion required for fluid flow, thus increasing the nitrite solution viscosity relative to that of an equivalent nitrate solution.« less

The relative viscosity of NaNO 3 and NaNO 2 aqueous solutions

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

Reynolds, Jacob G.; Mauss, Billie M.; Daniel, Richard C.

In aqueous solution, both nitrate and nitrite are planar, monovalent, and have the same elements but different sizes and charge densities. Comparing the viscosity of NaNO 2 and NaNO 3 aqueous solutions provides an opportunity to determine the relative importance of anion size versus strength of anion interaction with water. The viscosity of aqueous NaNO 2 and NaNO 3 were measured over a temperature and concentration range relevant to nuclear waste processing. The viscosity of NaNO 2 solutions was consistently larger than NaNO 3 under all conditions, even though nitrate is larger than nitrite. This was interpreted in terms ofmore » quantum mechanical charge field molecular dynamics calculations that indicate that nitrite forms more and stronger hydrogen bonds with water per oxygen atom than nitrate. Furthermore, these hydrogen bonds inhibit rotational motion required for fluid flow, thus increasing the nitrite solution viscosity relative to that of an equivalent nitrate solution.« less

Recovery of alkali metal constituents from catalytic coal conversion residues

DOEpatents

Soung, Wen Y.

1984-01-01

In a coal gasification operation (32) or similar conversion process carried out in the presence of an alkali metal-containing catalyst wherein particles containing alkali metal residues are produced, alkali metal constituents are recovered from the particles by contacting them (46, 53, 61, 69) with water or an aqueous solution to remove water-soluble alkali metal constituents and produce an aqueous solution enriched in said constituents. The aqueous solution thus produced is then contacted with carbon dioxide (63) to precipitate silicon constituents, the pH of the resultant solution is increased (81), preferably to a value in the range between about 12.5 and about 15.0, and the solution of increased pH is evaporated (84) to increase the alkali metal concentration. The concentrated aqueous solution is then recycled to the conversion process (86, 18, 17) where the alkali metal constituents serve as at least a portion of the alkali metal constituents which comprise the alkali metal-containing catalyst.

Freeze-thawing behaviour of highly concentrated aqueous alkali chloride-glucose systems.

PubMed

Kajiwara, K; Motegi, A; Murase, N

2001-01-01

The freeze-thawing behaviour of highly concentrated aqueous alkali chloride-glucose systems was investigated by differential scanning calorimetry (DSC). In the aqueous NaCl-glucose solution system, single or double glass transitions followed by the corresponding devitrification exotherms were observed during rewarming. In the aqueous KCl-glucose solution system, on the other hand, a single glass transition followed by an exotherm was observed during rewarming. The presence of double glass transitions observed for a certain composition of the aqueous NaCl-glucose solution was taken as an evidence for the liquid-liquid immiscibility at low temperatures. Two kinds of crystallisation accompanied by exotherms during rewarming were identified by X-ray diffraction as ice and ice/NaCl x 2H(2)O, or ice/KCl eutectic component.

Exploring Solute-Solvent Interactions of -Amino Acids in Aqueous [] Arrangements by Volumetric, Viscometric, Refractometric, and Acoustic Approach

NASA Astrophysics Data System (ADS)

Roy, Mahendra Nath; Roy, Milan Chandra; Basak, Saptarshi

2014-05-01

Qualitative and quantitative analysis of molecular interaction prevailing in glycine, l-alanine, l-valine, and aqueous solution of ionic liquid (IL) [1-ethylpyridinium tetrafluoroborate (] have been investigated by thermophysical properties. The apparent molar volume (), viscosity -coefficient, molal refraction (), and adiabatic compressibility ( of glycine, l-alanine, and l-valine have been studied in 0.001 mol , 0.003 mol , and 0.005 mol aqueous 1-ethylpyridinium tetrafluoroborate [] solutions at 298.15 K from the values of densities , viscosities (), refractive index (, and speed of sound , respectively. The extent of interaction, i.e., the solute-solvent interaction is expressed in terms of the limiting apparent molar volume (, viscosity -coefficient, and limiting apparent molar adiabatic compressibility (. The limiting apparent molar volumes (, experimental slopes ( derived from the Masson equation, and viscosity - and -coefficients using the Jones-Dole equation have been interpreted in terms of ion-ion and ion-solvent interactions, respectively. Molal refractions ( have been calculated with the help of the Lorentz-Lorenz equation. The role of the solvent (aqueous IL solution) and the contribution of solute-solute and solute-solvent interactions to the solution complexes have also been analyzed through the derived properties.

Selected specific rates of reactions of transients from water in aqueous solution. Hydrated electron, supplemental data. [Reactions with transients from water, with inorganic solutes, and with solutes

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

Ross, A.B.

1975-06-01

A compilation of rates of reactions of hydrated electrons with other transients and with organic and inorganic solutes in aqueous solution appeared in NSRDS-NBS 43, and covered the literature up to early 1971. This supplement includes additional rates which have been published through July 1973.

Options for refractive index and viscosity matching to study variable density flows

NASA Astrophysics Data System (ADS)

Clément, Simon A.; Guillemain, Anaïs; McCleney, Amy B.; Bardet, Philippe M.

2018-02-01

Variable density flows are often studied by mixing two miscible aqueous solutions of different densities. To perform optical diagnostics in such environments, the refractive index of the fluids must be matched, which can be achieved by carefully choosing the two solutes and the concentration of the solutions. To separate the effects of buoyancy forces and viscosity variations, it is desirable to match the viscosity of the two solutions in addition to their refractive index. In this manuscript, several pairs of index matched fluids are compared in terms of viscosity matching, monetary cost, and practical use. Two fluid pairs are studied in detail, with two aqueous solutions (binary solutions of water and a salt or alcohol) mixed into a ternary solution. In each case: an aqueous solution of isopropanol mixed with an aqueous solution of sodium chloride (NaCl) and an aqueous solution of glycerol mixed with an aqueous solution of sodium sulfate (Na_2SO_4). The first fluid pair allows reaching high-density differences at low cost, but brings a large difference in dynamic viscosity. The second allows matching dynamic viscosity and refractive index simultaneously, at reasonable cost. For each of these four solutes, the density, kinematic viscosity, and refractive index are measured versus concentration and temperature, as well as wavelength for the refractive index. To investigate non-linear effects when two index-matched, binary solutions are mixed, the ternary solutions formed are also analyzed. Results show that density and refractive index follow a linear variation with concentration. However, the viscosity of the isopropanol and NaCl pair deviates from the linear law and has to be considered. Empirical correlations and their coefficients are given to create index-matched fluids at a chosen temperature and wavelength. Finally, the effectiveness of the refractive index matching is illustrated with particle image velocimetry measurements performed for a buoyant jet in a linearly stratified environment. The creation of the index-matched solutions and linear stratification in a large-scale experimental facility are detailed, as well as the practical challenges to obtain precise refractive index matching.

Method for loading resin beds

DOEpatents

Notz, Karl J.; Rainey, Robert H.; Greene, Charles W.; Shockley, William E.

1978-01-01

An improved method of preparing nuclear reactor fuel by carbonizing a uranium loaded cation exchange resin provided by contacting a H.sup.+ loaded resin with a uranyl nitrate solution deficient in nitrate, comprises providing the nitrate deficient solution by a method comprising the steps of reacting in a reaction zone maintained between about 145.degree.-200.degree. C, a first aqueous component comprising a uranyl nitrate solution having a boiling point of at least 145.degree. C with a second aqueous component to provide a gaseous phase containing HNO.sub.3 and a reaction product comprising an aqueous uranyl nitrate solution deficient in nitrate.

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

NASA Technical Reports Server (NTRS)

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

2014-01-01

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

SEPARATION OF HAFNIUM FROM ZIRCONIUM

DOEpatents

Overholser, L.B.; Barton, C.J. Sr.; Ramsey, J.W.

1960-05-31

The separation of hafnium impurities from zirconium can be accomplished by means of organic solvent extraction. The hafnium-containing zirconium feed material is dissolved in an aqueous chloride solution and the resulting solution is contacted with an organic hexone phase, with at least one of the phases containing thiocyanate. The hafnium is extracted into the organic phase while zirconium remains in the aqueous phase. Further recovery of zirconium is effected by stripping the onganic phase with a hydrochloric acid solution and commingling the resulting strip solution with the aqueous feed solution. Hexone is recovered and recycled by means of scrubbing the onganic phase with a sulfuric acid solution to remove the hafnium, and thiocyanate is recovered and recycled by means of neutralizing the effluent streams to obtain ammonium thiocyanate.

RECOVERY OF PROTACTINIUM

DOEpatents

Kraus, K.A.; Moore, G.E.

1959-02-01

A process is presented for the separation of protactinium values from an aqueous solution containing Pa and Th values comprising establishing in the solution a HCl concentration of from 4 to 11 molar, contacting the resulting solution with an anion-exchange adsorbent, such as a polystyrene divinyl benzene polymer with quatenary amines as the active exchange group, to effect the adsorption of Pa values upon the adsorbent while leaving Th values in the solution, and then washlng the separated Pa bearing adsorbent with an aqueous solution of HCl of less than 4M to exclusively elute Pa values from the adsorbent. If hexavalent U values are contained in the original solution thcy are adsorbed on the resin together with Pa. A separation is offected chromatographically by percolating the resin with aqueous HCl.

Singlet Oxygen in Aqueous Solution: A Lecture Demonstration

ERIC Educational Resources Information Center

Shakhashiri, Bassam Z.; Williams, Lloyd G.

1976-01-01

Describes a demonstration that illustrates the red chemiluminescence due to singlet molecular oxygen that can be observed when aqueous solutions of hypochlorite ion and hydrogen peroxide are mixed. (MLH)

Thermodynamic studies of aqueous and CCl4 solutions of 15-crown-5 at 298.15 K: an application of McMillan-Mayer and Kirkwood-Buff theories of solutions.

PubMed

Dagade, Dilip H; Shetake, Poonam K; Patil, Kesharsingh J

2007-07-05

The density and osmotic coefficient data for solutions of 15-crown-5 (15C5) in water and in CCl4 solvent systems at 298.15 K have been reported using techniques of densitometry and vapor pressure osmometry in the concentration range of 0.01-2 mol kg-1. The data are used to obtain apparent molar and partial molar volumes, activity coefficients of the components as a function of 15C5 concentration. Using the literature heat of dilution data for aqueous system, it has become possible to calculate entropy of mixing (DeltaS(mix)), excess entropy of solution (DeltaS(E)), and partial molar entropies of the components at different concentrations. The results of all these are compared to those obtained for aqueous 18-crown-6 solutions reported earlier. It has been observed that the partial molar volume of 15C5 goes through a minimum and that of water goes through a maximum at approximately 1.2 mol kg(-1) in aqueous solutions whereas the opposite is true in CCl4 medium but at approximately 0.5 mol kg(-1). The osmotic and activity coefficients of 15C5 and excess free energy change for solution exhibit distinct differences in the two solvent systems studied. These results have been explained in terms of hydrophobic hydration and interactions in aqueous solution while weak solvophobic association of 15C5 molecules in CCl4 solutions is proposed. The data are further subjected to analysis by applying McMillan-Mayer and Kirkwood-Buff theories of solutions. The analysis shows that osmotic second virial coefficient value for 15C5 is marginally less than that of 18C6 indicating that reduction in ring flexibility does not affect the energetics of the interactions much in aqueous solution while the same gets influenced much in nonpolar solvent CCl4.

Stiffness-Independent Highly Efficient On-Chip Extraction of Cell-Laden Hydrogel Microcapsules from Oil Emulsion into Aqueous Solution by Dielectrophoresis.

PubMed

Huang, Haishui; Sun, Mingrui; Heisler-Taylor, Tyler; Kiourti, Asimina; Volakis, John; Lafyatis, Gregory; He, Xiaoming

2015-10-28

A dielectrophoresis (DEP)-based method achieves highly efficient on-chip extraction of cell-laden microcapsules of any stiffness from oil into aqueous solution. The hydrogel microcapsules can be extracted into the aqueous solution by DEP and interfacial tension forces with no trapped oil, while the encapsulated cells are free from electrical damage due to the Faraday cage effect. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

SOLVENT EXTRACTION PROCESS FOR PLUTONIUM

DOEpatents

Seaborg, G.T.

1959-04-14

The separation of plutonium from aqueous inorganic acid solutions by the use of a water immiscible organic extractant liquid is described. The plutonium must be in the oxidized state, and the solvents covered by the patent include nitromethane, nitroethane, nitropropane, and nitrobenzene. The use of a salting out agents such as ammonium nitrate in the case of an aqueous nitric acid solution is advantageous. After contacting the aqueous solution with the organic extractant, the resulting extract and raffinate phases are separated. The plutonium may be recovered by any suitable method.

Aqueous solution-chemical derived Nisbnd Al2O3 solar selective absorbing coatings. 2. Wetting agents and spreading of aqueous solutions on aluminum substrate

NASA Astrophysics Data System (ADS)

Li, Zhenxiang; Zhao, Jianxi

2013-03-01

Wettability of aluminum substrate by the aqueous solutions containing ethoxylated alcohol nonionic surfactants C12En- or Triton X-series was studied using dynamic contact angle measurements. The efficiency of wetting was found to strongly depend on the length of polyoxyethylene (POE) chain of C12En- or Triton X surfactants. For C12E4 that has a very short POE chain, it hardly made the aqueous solution spreading over aluminum. The others with a long POE chain were indeed very efficient in promoting the solution spreading. Moreover, all the spreading process could be completed within 10 s. The single-layer Nisbnd Al2O3 coatings were fabricated from the precursor solutions containing C12En- or Triton X surfactants and the reflectance spectra were measured by a UV/vis spectrophotometer equipped with an integrating sphere. The results indicated that the precursor solution with a long POE chain surfactant as wetting agent favored to fabricate a uniform film on the aluminum substrate and therefore to get a high solar absorptance.

Reaction behaviors of decomposition of monocrotophos in aqueous solution by UV and UV/O processes.

PubMed

Ku, Y; Wang, W; Shen, Y S

2000-02-01

The decomposition of monocrotophos (cis-3-dimethoxyphosphinyloxy-N-methyl-crotonamide) in aqueous solution by UV and UV/O(3) processes was studied. The experiments were carried out under various solution pH values to investigate the decomposition efficiencies of the reactant and organic intermediates in order to determine the completeness of decomposition. The photolytic decomposition rate of monocrotophos was increased with increasing solution pH because the solution pH affects the distribution and light absorbance of monocrotophos species. The combination of O(3) with UV light apparently promoted the decomposition and mineralization of monocrotophos in aqueous solution. For the UV/O(3) process, the breakage of the >C=C< bond of monocrotophos by ozone molecules was found to occur first, followed by mineralization by hydroxyl radicals to generate CO(3)(2-), PO4(3-), and NO(3)(-) anions in sequence. The quasi-global kinetics based on a simplified consecutive-parallel reaction scheme was developed to describe the temporal behavior of monocrotophos decomposition in aqueous solution by the UV/O(3) process.

Process for the extraction of technetium from uranium

DOEpatents

Gong, Cynthia-May S.; Poineau, Frederic; Czerwinski, Kenneth R.

2010-12-21

A spent fuel reprocessing method contacts an aqueous solution containing Technetium(V) and uranyl with an acidic solution comprising hydroxylamine hydrochloride or acetohydroxamic acid to reduce Tc(V) to Tc(II, and then extracts the uranyl with an organic phase, leaving technetium(II) in aqueous solution.

ADSORPTION OF CERIUM VALUES FROM AQUEOUS SOLUTIONS

DOEpatents

Roberts, F.P.

1963-08-13

Cerium can be removed from aqueous nitric acid (2 to 13 M) solutions by passing the latter over a PbO/sub 2/-containing anion exchange resin. The cerium is taken up by the resin, while any lanthanides, yttrium, and strontium present remain in the solution. (AEC)

Method for separating water soluble organics from a process stream by aqueous biphasic extraction

DOEpatents

Chaiko, David J.; Mego, William A.

1999-01-01

A method for separating water-miscible organic species from a process stream by aqueous biphasic extraction is provided. An aqueous biphase system is generated by contacting a process stream comprised of water, salt, and organic species with an aqueous polymer solution. The organic species transfer from the salt-rich phase to the polymer-rich phase, and the phases are separated. Next, the polymer is recovered from the loaded polymer phase by selectively extracting the polymer into an organic phase at an elevated temperature, while the organic species remain in a substantially salt-free aqueous solution. Alternatively, the polymer is recovered from the loaded polymer by a temperature induced phase separation (cloud point extraction), whereby the polymer and the organic species separate into two distinct solutions. The method for separating water-miscible organic species is applicable to the treatment of industrial wastewater streams, including the extraction and recovery of complexed metal ions from salt solutions, organic contaminants from mineral processing streams, and colorants from spent dye baths.

Thermodynamic Parameters of the Dissolution of 4-Hydroxy-L-Proline and L-Phenylalanine in Mixed Aqueous Solvents at 298 K

NASA Astrophysics Data System (ADS)

Smirnov, V. I.; Badelin, V. G.

2018-01-01

The enthalpies of solution of 4-hydroxy-L-proline and L-phenylalanine in binary mixed aqueous solvents containing acetonitrile (AN), 1,4-dioxane (1,4-DO), or acetone (AC) at mole fractions of 0 to 0.25 are determined at T = 298.15 K via isothermal calorimetry. The standard enthalpies of solution (Δsol H°) and transfer (Δtr H°) of 4-hydroxy-L-proline and L-phenylalanine from water to mixed aqueous solvents are calculated using the experimental calorimetric data, as are the enthalpy coefficients of paired interactions ( h xy ) between the molecules of the investigated amino acids and the organic solvents. The effects the mixed aqueous solvent composition and the structure of the organic solvent molecules have on the enthalpies of solution and transfer for the investigated amino acids are considered. The correlation between the enthalpy of solution of the amino acids and the electron-donating properties of the organic solvents in the mixed aqueous solvent systems is established.

Use of solid phase extraction (SPE) to evaluate in vitro skin permeation of aescin.

PubMed

Montenegro, L; Carbone, C; Giannone, I; Puglisi, G

2007-05-01

The aim of this work was to evaluate the feasibility of assessing aescin in vitro permeation through human skin by determining the amount of aescin permeated using conventional HPLC procedures after extraction of skin permeation samples by means of solid phase extraction (SPE). Aescin in vitro skin permeation was assessed from aqueous solutions and gels using both Franz-type diffusion cells and flow-through diffusion cells. The SPE method used was highly accurate (mean accuracy 99.66%), highly reproducible (intra-day and inter-day variations lower than 2.3% and 2.2%, respectively) and aescin recovery from normal saline was greater than 99%. The use of Franz-type diffusion cells did not allow us to determine aescin flux values through excised human skin, therefore aescin skin permeation parameters could be calculated only using flow-through diffusion cells. Plotting the cumulative amount of aescin permeated as a function of time, linear relationships were obtained from both aqueous solution and gel using flow-through diffusion cells. Aescin flux values through excised human skin from aqueous gel were significantly lower than those observed from aqueous solution (p < 0.05). Calculating aescin percutaneous absorption parameters we evidenced that aescin partition coefficient was lower from the aqueous gel with respect to the aqueous solution. Therefore, the SPE method used in this study was suitable to determine aescin in vitro skin permeation parameters from aqueous solutions and gels using a conventional HPLC method for the analysis of the skin permeation samples.

21 CFR 163.112 - Breakfast cocoa.

Code of Federal Regulations, 2012 CFR

2012-04-01

... oxide, used as such, or in aqueous solution; (2) Neutralizing agents. Phosphoric acid, citric acid and L-tartaric acid, used as such, or in aqueous solution; (3) Spices, natural and artificial flavorings, and...

21 CFR 163.112 - Breakfast cocoa.

Code of Federal Regulations, 2014 CFR

2014-04-01

... oxide, used as such, or in aqueous solution; (2) Neutralizing agents. Phosphoric acid, citric acid and L-tartaric acid, used as such, or in aqueous solution; (3) Spices, natural and artificial flavorings, and...

21 CFR 163.112 - Breakfast cocoa.

Code of Federal Regulations, 2013 CFR

2013-04-01

... oxide, used as such, or in aqueous solution; (2) Neutralizing agents. Phosphoric acid, citric acid and L-tartaric acid, used as such, or in aqueous solution; (3) Spices, natural and artificial flavorings, and...

Method for gettering organic, inorganic and elemental iodine in aqueous solutions

DOEpatents

Beahm, Edward C.; Shockley, William E.

1990-07-03

A process for the removal of iodine from aqueous solutions, particularly the trapping of radioactive iodine to mitigate damage resulting from accidents or spills associated with nuclear reactors, by exposing the solution to well dispersed silver carbonate which reacts with the iodine and iodides, thereby gettering iodine and iodine compounds from solution. The iodine is not only removed from solution but also from the contiguous vapor.

Method for gettering organic, inorganic and elemental iodine in aqueous solutions

DOEpatents

Beahm, Edward C.; Shockley, William E.

1990-01-01

A process for the removal of iodine from aqueous solutions, particularly the trapping of radioactive iodine to mitigate damage resulting from accidents or spills associated with nuclear reactors, by exposing the solution to well dispersed silver carbonate which reacts with the iodine and iodides, thereby gettering iodine and iodine compounds from solution. The iodine is not only removed from solution but also from the contiguous vapor.

Crystal growth in fused solvent systems

NASA Technical Reports Server (NTRS)

Ulrich, D. R.; Noone, M. J.; Spear, K. E.; White, W. B.; Henry, E. C.

1973-01-01

Research is reported on the growth of electronic ceramic single crystals from solution for the future growth of crystals in a microgravity environment. Work included growth from fused or glass solvents and aqueous solutions. Topics discussed include: crystal identification and selection; aqueous solution growth of triglycine sulphate (TGS); and characterization of TGS.

MODELING SMALL-SCALE SPILLS OF AQUEOUS SOLUTIONS IN THE INDOOR ENVIRONMENT

EPA Science Inventory

A mass transfer model is proposed to estimate the rates of chemical emissions from aqueous solutions spilled on hard surfaces inside buildings. The model is presented in two forms: a set of four ordinary differential equations and a simplified exact solution. The latter can be ...

Rheological characterization of solutions and thin films made from amylose-hexadecylammonium chloride inclusion complexes and polyvinyl alcohol

USDA-ARS?s Scientific Manuscript database

The rheological properties of aqueous solutions and films made from blends of polyvinyl alcohol (PVOH) and amylose-hexadecylammonium chloride inclusion complexes (Hex-Am) were investigated to better understand the polymer interactions and processing parameters. Aqueous solutions of Hex-Am displayed ...

Study on Latent Heat of Fusion of Ice in Aqueous Solutions

NASA Astrophysics Data System (ADS)

Kumano, Hiroyuki; Asaoka, Tatsunori; Saito, Akio; Okawa, Seiji

In this study, latent heat of fusion of ice in aqueous solutions was measured to understand latent heat of fusion of ice slurries. Propylene glycol, ethylene glycol, ethanol, NaCl and NaNO3 solutions were examined as the aqueous solutions. In the measurement, pure ice was put into the solution, and the temperature variation of the solution due to the melting of the ice was measured. Then, the effective latent heat of fusion was calculated from energy balance equation. When ice melts in solution, the concentration of the solution varies due to the melting of the ice, and dilution heat must be considered. Therefore, the latent heat of fusion of ice in aqueous solutions was predicted by considering the effects of dilution and freezing-point depression. The latent heat of fusion was also measured by differential scanning calorimetry(DSC) to compare the results obtained from the experiments with that obtained by DSC. As the result, it was found that the effective latent heat of fusion of ice decreased with the increase of the concentration of solution, and the effective latent heat of fusion was calculated from latent heat of fusion of pure ice and the effects of freezing-point depression and the dilution heat.

Direct Detection of Aqueous CO2 by Infrared Waveguide Spectroscopy with an Amorphous Fluoropolymer Coating Rod.

PubMed

Hotta, Hiroki; Miki, Yuko; Kawaguchi, Yukiko; Tsunoda, Kin-Ichi; Nakaoka, Atsuko; Ko, Sho; Kimoto, Takashi

2017-01-01

Infrared waveguide spectroscopy using a sapphire rod coated with an amorphous fluoropolymer (Cytop, Asahi Glass Co., ltd, Japan) has been developed in order to directly observe CO 2 in aqueous solutions. Since the amorphous fluoropolymer has a relatively high gas-permeability and hydrophobic feature, the aqueous CO 2 transmits into the amorphous fluoropolymer coating film, but water cannot penetrate into the film. Good linearity of calibration curves for CO 2 in the gas and the aqueous solution were obtained.

POLONIUM SEPARATION PROCESS

DOEpatents

Karraker, D.G.

1959-07-14

A liquid-liquid extraction process is presented for the recovery of polonium from lead and bismuth. According to the invention an acidic aqueous chloride phase containing the polonium, lead, and bismuth values is contacted with a tributyl phosphate ether phase. The polonium preferentially enters the organic phase which is then separated and washed with an aqueous hydrochloric solution to remove any lead or bismuth which may also have been extracted. The now highly purified polonium in the organic phase may be transferred to an aqueous solution by extraction with aqueous nitric acid.

Microbial solubilization of phosphate

DOEpatents

Rogers, R.D.; Wolfram, J.H.

1993-10-26

A process is provided for solubilizing phosphate from phosphate containing ore by treatment with microorganisms which comprises forming an aqueous mixture of phosphate ore, microorganisms operable for solubilizing phosphate from the phosphate ore and maintaining the aqueous mixture for a period of time and under conditions operable to effect the microbial solubilization process. An aqueous solution containing soluble phosphorus can be separated from the reacted mixture by precipitation, solvent extraction, selective membrane, exchange resin or gravity methods to recover phosphate from the aqueous solution. 6 figures.

Microbial solubilization of phosphate

DOEpatents

Rogers, Robert D.; Wolfram, James H.

1993-01-01

A process is provided for solubilizing phosphate from phosphate containing ore by treatment with microorganisms which comprises forming an aqueous mixture of phosphate ore, microorganisms operable for solubilizing phosphate from the phosphate ore and maintaining the aqueous mixture for a period of time and under conditions operable to effect the microbial solubilization process. An aqueous solution containing soluble phosphorous can be separated from the reacted mixture by precipitation, solvent extraction, selective membrane, exchange resin or gravity methods to recover phosphate from the aqueous solution.

Relation between the adsorbed quantity and the immersion enthalpy in catechol aqueous solutions on activated carbons.

PubMed

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

2012-01-01

An activated carbon, Carbochem(TM)-PS230, was modified by chemical and thermal treatment in flow of H(2), 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 pK(a). 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).

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

75 FR 30844 - General Mills, Inc.; Withdrawal of Food Additive Petition

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-02

... for the reduction of pathogens and other microorganisms in aqueous sugar solutions and potable water... reduction of pathogens and other microorganisms in aqueous sugar solutions and potable water intended for...

Structural characterization of metal complexes in aqueous solutions: a XAS study of stannous fluoride

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

Alsina, Marco A.; Gaillard, Jean-François

The identity and structure of tin(ii)-fluoride complexes formed in aqueous solutions are determined by combining X-ray absorption spectroscopy, thermodynamic modeling and quantum mechanical calculations.

Sorption of ochratoxin A from aqueous solutions using β-cyclodextrin-polyurethane polymer.

PubMed

Appell, Michael; Jackson, Michael A

2012-02-01

The ability of a cyclodextrin-polyurethane polymer to remove ochratoxin A from aqueous solutions was examined by batch rebinding assays. The results from the aqueous binding studies were fit to two parameter models to gain insight into the interaction of ochratoxin A with the nanosponge material. The ochratoxin A sorption data fit well to the heterogeneous Freundlich isotherm model. The polymer was less effective at binding ochratoxin A in high pH buffer (9.5) under conditions where ochratoxin A exists predominantly in the dianionic state. Batch rebinding assays in red wine indicate the polymer is able to remove significant levels of ochratoxin A from spiked solutions between 1-10 μg·L(-1). These results suggest cyclodextrin nanosponge materials are suitable to reduce levels of ochratoxin A from spiked aqueous solutions and red wine samples.

Superlubricity of a Mixed Aqueous Solution

NASA Astrophysics Data System (ADS)

Ma, Zhi-Zuo; Zhang, Chen-Hui; Luo, Jian-Bin; Lu, Xin-Chun; Wen, Shi-Zhu

2011-05-01

A super-low friction coefficient of 0.0028 is measured under a pressure of 300 MPa when the friction pair (the silicon nitride ball sliding on the silicate glass) is lubricated by the mixed aqueous solution of glycerol and boric acid. The morphorlogies of the hydroxylated glass plate are observed by an atomic force microscope (AFM) in deionized water, glycerol, boric acid and their mixed aqueous solution. Bonding peaks of the retained liquids adhered on the surface of the sliding track are detected by an infrared spectrum apparatus and a Raman spectrum apparatus. The mechanism of the superlubricity of the glycerol and boric acid mixed aqueous solution is discussed. It is deduced that the formation of the lubricant film has enough strength to support higher loads, the hydration effect offering the super lower shear resistance. Key words: superlubricity, water based lubricant, ultra-low friction

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.

Methods for separating medical isotopes using ionic liquids

DOEpatents

Luo, Huimin; Boll, Rose Ann; Bell, Jason Richard; Dai, Sheng

2014-10-21

A method for extracting a radioisotope from an aqueous solution, the method comprising: a) intimately mixing a non-chelating ionic liquid with the aqueous solution to transfer at least a portion of said radioisotope to said non-chelating ionic liquid; and b) separating the non-chelating ionic liquid from the aqueous solution. In preferred embodiments, the method achieves an extraction efficiency of at least 80%, or a separation factor of at least 1.times.10.sup.4 when more than one radioisotope is included in the aqueous solution. In particular embodiments, the method is applied to the separation of medical isotopes pairs, such as Th from Ac (Th-229/Ac-225, Ac-227/Th-227), or Ra from Ac (Ac-225 and Ra-225, Ac-227 and Ra-223), or Ra from Th (Th-227 and Ra-223, Th-229 and Ra-225).

Densities of L-Glutamic Acid HCl Drug in Aqueous NaCl and KCl Solutions at Different Temperatures

NASA Astrophysics Data System (ADS)

Ryshetti, Suresh; Raghuram, Noothi; Rani, Emmadi Jayanthi; Tangeda, Savitha Jyostna

2016-04-01

Densities (ρ ) of (0.01 to 0.07) {mol}{\\cdot } {kg}^{-1} L-Glutamic acid HCl (L-HCl) drug in water, and in aqueous NaCl and KCl (0.5 and 1.0) {mol}{\\cdot } {kg}^{-1} solutions have been reported as a function of temperature at T = (298.15, 303.15, 308.15, and 313.15) K and atmospheric pressure. The accurate density (ρ ) values are used to estimate the various parameters such as the apparent molar volume (V_{2,{\\upphi }}), the partial molar volume (V2^{∞}), the isobaric thermal expansion coefficient (α 2), the partial molar expansion (E2^{∞}), and Hepler's constant (partial 2V2^{∞}/partial T2)P. The Cosphere overlap model is used to understand the solute-solvent interactions in a ternary mixture (L-HCl drug + NaCl or KCl + water). Hepler's constant (partial 2V2^{∞}/partial T2)_P is utilized to interpret the structure-making or -breaking ability of L-HCl drug in aqueous NaCl and KCl solutions, and the results are inferred that L-HCl drug acts as a structure maker, i.e., kosmotrope in aqueous NaCl solutions and performs as a structure breaker, i.e., chaotrope in aqueous KCl solutions.

Heat capacity of alkanolamine aqueous solutions

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

Chiu, L.F.; Li, M.H.

1999-12-01

Heat capacities of monoethanoloamine, diglycolamine, diethanolamine, di-w propanolamine, triethanolamine, N-methyldiethanolamine, 2-amino-2-methyl-l-propanol, and 2-piperidineethanol aqueous solutions were measured from 30 to 80 C with a differential scanning calorimeter (DSC). The mole fractions of alkanolamines studied are 0.2, 0.4, 0.6, and 0.8. Heat capacities of N-methyldiethanolamine aqueous solutions have been measured to verify the validity of C{sub p} measurements for alkanolamine aqueous solutions. The estimated uncertainty of the measured heat capacities is {plus{underscore}minus}3%, including the effect of up to 5% impurities in a substance. An excess molar heat capacity expression using the Redlich-Kister equation for the composition dependence is used to representmore » the measured C{sub p} of alkanolamine aqueous solutions. For a total of 374 data points, the calculation results for eight alkanolamine solutions give the overall average absolute deviations of 11.9% and 0.29% for the excess molar heat capacity and the heat capacity, respectively. The heat capacities presented in this study are, in general, of sufficient accuracy for most engineering-design calculations. Solutions of alkanolamines are industrially important mixtures used in the natural gas industry, oil refineries, petroleum chemical plants, and synthetic ammonia plants for the removal of acidic components such as CO{sub 2} and H{sub 2}S from gas streams.« less

METHOD OF APPLYING COPPER COATINGS TO URANIUM

DOEpatents

Gray, A.G.

1959-07-14

A method is presented for protecting metallic uranium, which comprises anodic etching of the uranium in an aqueous phosphoric acid solution containing chloride ions, cleaning the etched uranium in aqueous nitric acid solution, promptly electro-plating the cleaned uranium in a copper electro-plating bath, and then electro-plating thereupon lead, tin, zinc, cadmium, chromium or nickel from an aqueous electro-plating bath.

Pre-formulation and chemical stability studies of penethamate, a benzylpenicillin ester prodrug, in aqueous vehicles.

PubMed

Jain, Rohit; Wu, Zimei; Bork, Olaf; Tucker, Ian G

2012-01-01

Penethamate (PNT) is a diethylaminoethyl ester prodrug of benzylpenicillin used to treat bovine mastitis via the intramuscular route. Because of its instability, PNT products must be reconstituted before administration and the reconstituted injection has a short shelf life (7 days at 2-8°C). The purpose of this paper was to investigate whether the stability of PNT can be improved in order to achieve a chemically stable ready-to-use aqueous-based PNT formulation or at least to extend the shelf life of the reconstituted suspension. A chemical stability study of PNT in aqueous-based solutions as a function of pH, buffer strength, solvent mixtures and temperature, supported by studies of its solubility in mixed solvents, allowed predictions of the shelf life of PNT solution and suspension formulations. PNT degraded in aqueous solutions by several pathways over the pH range 2.0-9.3 with a V-shaped pH-rate profile and a minimum pH of around 4.5. The stability of PNT solutions in mixed solvents was greater than in aqueous solutions. For example, in propylene glycol:citrate buffer (60:40, v/v, pH 4.5), the half-life of PNT was 4.3 days compared with 1.8 days in aqueous buffer. However, solubility of PNT in the mixed solvent was higher than that in aqueous solution and this had an adverse effect on the stability of suspensions. By judicious choosing of pH and mixed solvent, it is possible to achieve a storage life of a PNT suspension of 5.5 months at 5°C, not sufficient for a ready-to-use product but a dramatic improvement in the storage life of the reconstituted product.

Desorption of CO{sub 2} from MDEA and activated MDEA solutions

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

Xu, G.W.; Zhang, C.F.; Qin, S.J.

1995-03-01

A packed column was used for investigating the desorption rate of CO{sub 2} from aqueous methyldiethanolamine (MDEA) and activated MDEA solutions. Experiments were conducted within the temperature range 30--70 C, the concentration of MDEA was 4.28 kmol/m{sup 3}, and the concentration of piperazine (PZ) was 0.10 kmol/m{sup 3} for aqueous activated MDEA solutions. Experimental data confirmed that the kinetics model of absorption CO{sub 2} into aqueous MDEA and activated MDEA solutions can be applicable to the situations in which desorption occurs, and the desorption rate of model predictions agree well with that of experimental determination.

Separation of metal ions from aqueous solutions

DOEpatents

Almon, Amy C.

1994-01-01

A process and apparatus for quantitatively and selectively separating metal ions from mixtures thereof in aqueous solution. The apparatus includes, in combination, a horizontal electrochemical flow cell containing flow bulk electrolyte solution and an aqueous, metal ion-containing solution, the cell containing a metal mesh working electrode, a counter electrode positioned downstream from the working electrode, an independent variable power supply/potentiostat positioned outside of the flow cell and connected to the electrodes, and optionally a detector such as a chromatographic detector, positioned outside the flow cell. This apparatus and its operation has significant application where trace amounts of metal ions are to be separated.

Calculating the thermodynamic properties of aqueous solutions of alkali metal carboxylates

NASA Astrophysics Data System (ADS)

Rudakov, A. M.; Sergievskii, V. V.; Zhukova, T. V.

2014-06-01

A modified Robinson-Stokes equation with terms that consider the formation of ionic hydrates and associates is used to describe thermodynamic properties of aqueous solutions of electrolytes. The model is used to describe data on the osmotic coefficients of aqueous solutions of alkali metal carboxylates, and to calculate the mean ionic activity coefficients of salts and excess Gibbs energies. The key contributions from ionic hydration and association to the nonideality of solutions is determined by analyzing the contributions of various factors. Relations that connect the hydration numbers of electrolytes with the parameters of the Pitzer-Mayorga equation and a modified Hückel equation are developed.

A Modified Robinson-Stokes equation for describing the thermodynamic properties of aqueous solutions of 1-1 electrolytes

NASA Astrophysics Data System (ADS)

Rudakov, A. M.; Sergievskii, V. V.

2008-05-01

Equations relating osmotic, mean ionic activity, and water activity coefficients to electrolyte concentrations in binary aqueous solutions were substantiated within the framework of cluster concepts. The model includes the contribution to solution nonideality of electrostatic interactions in terms of the Debye-Hückel theory along with hydration and association of salts via relations containing hydration and association numbers in the standard states. According to the description of data on 54 aqueous solutions of 1-1 electrolytes, this model should be given preference compared with the most extensively used NRTL, NRTL-NRF, Wilson, and Pitzer models.

Heat-induced morphological transformation of gold nanodumbbells in ionic surfactant solutions

NASA Astrophysics Data System (ADS)

Wen, Ting-Chun; Lu, Chung-Wen; Hsieh, Wei-Chi; Chang, Sheng-Te; Yang, Ya-Ting; Deng, Jin-Pei

2018-01-01

The thermal stability of gold nanodumbbells (NDs) is studied in aqueous solution of ionic surfactants. It is found in aqueous solution of cetyltrimethylammonium bromide that the blue-shift of longitudinal surface plasmon resonance band of gold NDs occurs at 75 °C and the new gold nanorods (NRs) with shortened aspect ratio are formed at the same time. The aspect ratio of the generated gold NRs gradually decreases and finally approaches ∼1.7 after repeated processing. Similarly, the same results are also obtained in aqueous solution of sodium dodecyl sulfate at room temperature. Mechanism is proposed for the shape transformation of gold NDs.

Laboratory studies of aqueous-phase oxidation of polyols in submicron particles

NASA Astrophysics Data System (ADS)

Daumit, K. E.; Carrasquillo, A. J.; Hunter, J. F.; Kroll, J. H.

2013-12-01

Aqueous-phase oxidation has received recent attention as a potential pathway for the formation of highly oxidized organic aerosol. However most aqueous oxidation studies are performed in bulk solutions rather than aqueous droplets. Here we describe experiments in which aqueous oxidation is carried out within submicron particles, allowing for gas-particle partitioning of reactants, intermediates, and products. Using Fenton chemistry as a source of hydroxyl radicals, and a high-resolution aerosol mass spectrometer (AMS) for online characterization of particle composition, we find that aqueous oxidation can be quite rapid. The formation of high concentrations of oxalic acid is observed in the particle phase with some loss of carbon to the gas phase, indicating the formation of volatile products. We see a rapid degradation of condensed-phase oxidation products upon exposure to ultraviolet lights (centered at 350 nm) suggesting that these products may exist as iron(III)-oxalate complexes. Similar results are also seen when oxidation is carried out in bulk solution (with AMS analysis of the atomized solution); however in some cases the mass loss is less than is observed for submicron particles, likely due to differences in partitioning of early-generation products. Such products can partition out of the aqueous phase at the low liquid water contents in the chamber but remain in solution for further aqueous processing in bulk oxidation experiments. This work suggests that the product distributions from oxidation in aqueous aerosol may be substantially different than those in bulk oxidation, pointing to the need to carry out aqueous oxidation studies under atmospherically relevant partitioning conditions (with liquid water contents mimicking those of cloud droplets or wet aerosol).

An ex vivo human aqueous humor-concentration comparison of two commercial bromfenac formulations

PubMed Central

Walters, Thomas R; Smyth-Medina, Robert J; Cockrum, Paul C

2018-01-01

Purpose The purpose of this study was to quantify the concentration of bromfenac in the aqueous humor utilizing high-performance liquid chromatography mass spectrometry between two commercial nonsteroidal anti-inflammatory drugs, using aqueous humor concentrations to characterize pharmacokinetic proportional differences between 0.075% bromfenac ophthalmic solution in DuraSite (BromSite®) and 0.09% bromfenac ophthalmic solution (Bromday®). Methods In this multicenter, randomized, double-masked, two-arm, parallel-group, comparative, Phase II clinical trial, subjects were assigned to receive bromfenac in DuraSite or bromfenac ophthalmic solution in a 1:1 ratio. One drop of the masked test article was instilled into the study eye once a day for 2 days prior to and 3 hours prior (last instillation) to the subject’s cataract surgery. Aqueous humor samples were collected upon initial cataract incision for analysis of bromfenac levels. The primary end point was aqueous humor concentration of bromfenac at Day 3, at the initiation of cataract surgery. Aqueous humor samples were collected and analyzed for bromfenac levels. Results A total of 60 subjects completed the study, 30 in each group. The mean bromfenac aqueous humor concentration in subjects who received bromfenac in DuraSite was more than twice (49.33±41.87 ng/mL, P=0.004) that of subjects who received bromfenac ophthalmic solution (23.65±16.31 ng/mL) after three doses. Conclusion Mean bromfenac aqueous humor concentration in subjects receiving the DuraSite-containing bromfenac in DuraSite (0.075%) was significantly higher compared to subjects receiving bromfenac ophthalmic solution (0.09%) after 3 days of dosing. PMID:29849449

Theoretic Study on Dispersion Mechanism of Boron Nitride Nanotubes by Polynucleotides

PubMed Central

Liang, Lijun; Hu, Wei; Zhang, Zhisen; Shen, Jia-Wei

2016-01-01

Due to the unique electrical and mechanical properties of boron nitride nanotubes (BNNT), BNNT has been a promising material for many potential applications, especially in biomedical field. Understanding the dispersion of BNNT in aqueous solution by biomolecules is essential for its use in biomedical applications. In this study, BNNT wrapped by polynucleotides in aqueous solution was investigated by molecular dynamics (MD) simulations. Our results demonstrated that the BNNT wrapped by polynucleotides could greatly hinder the aggregation of BNNTs and improve the dispersion of BNNTs in aqueous solution. Dispersion of BNNTs with the assistance of polynucleotides is greatly affected by the wrapping manner of polynucleotides on BNNT, which mainly depends on two factors: the type of polynucleotides and the radius of BNNT. The interaction between polynucleotides and BNNT(9, 9) is larger than that between polynucleotides and BNNT(5, 5), which leads to the fact that dispersion of BNNT(9, 9) is better than that of BNNT(5, 5) with the assistance of polynucleotides in aqueous solution. Our study revealed the molecular-level dispersion mechanism of BNNT with the assistance of polynucleotides in aqueous solution. It shades a light on the understanding of dispersion of single wall nanotubes by biomolecules. PMID:28004832

Photolysis of Diazo Dye in Aqueous Solutions of Metal Nitrates

NASA Astrophysics Data System (ADS)

Volkova, N. A.; Evstrop'ev, S. K.; Istomina, O. V.; Kolobkova, E. V.

2018-04-01

The photolysis of Chicago Blue Sky diazo dye is studied. It is experimentally shown that the presence of metal nitrates in aqueous solutions changes the photolysis mechanism and sharply increases the photolysis rate.

Multiple stimulus reversible hydrogels

DOEpatents

Gutowska, Anna; Krzyminski, Karol J.

2003-12-09

A polymeric solution capable of gelling upon exposure to a critical minimum value of a plurality of environmental stimuli is disclosed. The polymeric solution may be an aqueous solution utilized in vivo and capable of having the gelation reversed if at least one of the stimuli fall below, or outside the range of, the critical minimum value. The aqueous polymeric solution can be used either in industrial or pharmaceutical environments. In the medical environment, the aqueous polymeric solution is provided with either a chemical or radioisotopic therapeutic agent for delivery to a specific body part. The primary advantage of the process is that exposure to one environmental stimuli alone will not cause gelation, thereby enabling the therapeutic agent to be conducted through the body for relatively long distances without gelation occurring.

Multiple stimulus reversible hydrogels

DOEpatents

Gutowska, Anna; Krzyminski, Karol J.

2006-04-25

A polymeric solution capable of gelling upon exposure to a critical minimum value of a plurality of environmental stimuli is disclosed. The polymeric solution may be an aqueous solution utilized in vivo and capable of having the gelation reversed if at least one of the stimuli fall below, or outside the range of, the critical minimum value. The aqueous polymeric solution can be used either in industrial or pharmaceutical environments. In the medical environment, the aqueous polymeric solution is provided with either a chemical or radioisotopic therapeutic agent for delivery to a specific body part. The primary advantage of the process is that exposure to one environmental stimuli alone will not cause gelation, thereby enabling the therapeutic agent to be conducted through the body for relatively long distances without gelation occurring.

Removal of metal ions from aqueous solution

DOEpatents

Jackson, Paul J.; Delhaize, Emmanuel; Robinson, Nigel J.; Unkefer, Clifford J.; Furlong, Clement

1990-01-01

A method of removing heavy metals from aqueous solution, a composition of matter used in effecting said removal, and apparatus used in effecting said removal. One or more of the polypeptides, poly (.gamma.-glutamylcysteinyl)glycines, is immobilized on an inert material in particulate form. Upon contact with an aqueous solution containing heavy metals, the polypeptides sequester the metals, removing them from the solution. There is selectivity of poly (.gamma.-glutamylcysteinyl)glycines having a particular number of monomer repeat units for particular metals. The polypeptides are easily regenerated by contact with a small amount of an organic acid, so that they can be used again to remove heavy metals from solution. This also results in the removal of the metals from the column in a concentrated form.

Removal of metal ions from aqueous solution

DOEpatents

Jackson, Paul J.; Delhaize, Emmanuel; Robinson, Nigel J.; Unkefer, Clifford J.; Furlong, Clement

1990-11-13

A method of removing heavy metals from aqueous solution, a composition of matter used in effecting said removal, and apparatus used in effecting said removal. One or more of the polypeptides, poly (.gamma.-glutamylcysteinyl)glycines, is immobilized on an inert material in particulate form. Upon contact with an aqueous solution containing heavy metals, the polypeptides sequester the metals, removing them from the solution. There is selectivity of poly (.gamma.-glutamylcysteinyl)glycines having a particular number of monomer repeat unit for particular metals. The polypeptides are easily regenerated by contact with a small amount of an organic acid, so that they can be used again to remove heayv metals from solution. This also results in the removal of the metals from the column in a concentrated form.

Long-term results of treatment with diquafosol ophthalmic solution for aqueous-deficient dry eye.

PubMed

Koh, Shizuka; Ikeda, Chikako; Takai, Yoshihiro; Watanabe, Hitoshi; Maeda, Naoyuki; Nishida, Kohji

2013-09-01

To evaluate the preliminary long-term efficacy of diquafosol ophthalmic solution for aqueous-deficient dry eye. Fifteen patients with mild-to-moderate aqueous-deficient dry eye were enrolled. After a washout period, the patients were treated with 3 % diquafosol ophthalmic solution for 6 months. We assessed 12 subjective dry eye symptoms, corneal and conjunctival staining with fluorescein, tear film break-up time (BUT), lower tear meniscus height measured with anterior-segment optical coherence tomography, Schirmer's testing, and adverse reactions at baseline and 1, 3, and 6 months after the start of treatment. Treatment with diquafosol ophthalmic solution significantly improved dry eye symptoms, corneal staining, BUT, and tear meniscus height at 1 month and maintained the effectiveness for 6 months. Conjunctival staining significantly improved 3 and 6 months after treatment. No significant adverse reactions developed. Prolonged use of diquafosol ophthalmic solution for 6 months produced significant improvement both subjectively (dry eye symptom score) and objectively (ocular staining score and tear function tests) for aqueous-deficient dry eye.

Coatable Li4 SnS4 Solid Electrolytes Prepared from Aqueous Solutions for All-Solid-State Lithium-Ion Batteries.

PubMed

Choi, Young Eun; Park, Kern Ho; Kim, Dong Hyeon; Oh, Dae Yang; Kwak, Hi Ram; Lee, Young-Gi; Jung, Yoon Seok

2017-06-22

Bulk-type all-solid-state lithium-ion batteries (ASLBs) for large-scale energy-storage applications have emerged as a promising alternative to conventional lithium-ion batteries (LIBs) owing to their superior safety. However, the electrochemical performance of bulk-type ASLBs is critically limited by the low ionic conductivity of solid electrolytes (SEs) and poor ionic contact between the active materials and SEs. Herein, highly conductive (0.14 mS cm -1 ) and dry-air-stable SEs (Li 4 SnS 4 ) are reported, which are prepared using a scalable aqueous-solution process. An active material (LiCoO 2 ) coated by solidified Li 4 SnS 4 from aqueous solutions results in a significant improvement in the electrochemical performance of ASLBs. Side-effects of the exposure of LiCoO 2 to aqueous solutions are minimized by using predissolved Li 4 SnS 4 solution. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

METHOD FOR SEPARATION OF PLUTONIUM FROM URANIUM AND FISSION PRODUCTS BY SOLVENT EXTRACTION

DOEpatents

Seaborg, G.T.; Blaedel, W.J.; Walling, M.T. Jr.

1960-08-23

A process is given for separating from each other uranium, plutonium, and fission products in an aqueous nitric acid solution by the so-called Redox process. The plutonium is first oxidized to the hexavalent state, e.g., with a water-soluble dichromate or sodium bismuthate, preferably together with a holding oxidant such as potassium bromate. potassium permanganate, or an excess of the oxidizing agent. The solution is then contacted with a water-immiscible organic solvent, preferably hexone. whereby uranium and plutonium are extracted while the fission products remain in the aqueous solution. The separated organic phase is then contacted with an aqueous solution of a reducing agent, with or without a holding reductant (e.g., with a ferrous salt plus hydrazine or with ferrous sulfamate), whereby plutonium is reduced to the trivalent state and back- extracted into the aqueous solution. The uranium may finally be back-extracted from the organic solvent (e.g., with a 0.1 N nitric acid).

Electronic structure of aqueous solutions: Bridging the gap between theory and experiments.

PubMed

Pham, Tuan Anh; Govoni, Marco; Seidel, Robert; Bradforth, Stephen E; Schwegler, Eric; Galli, Giulia

2017-06-01

Predicting the electronic properties of aqueous liquids has been a long-standing challenge for quantum mechanical methods. However, it is a crucial step in understanding and predicting the key role played by aqueous solutions and electrolytes in a wide variety of emerging energy and environmental technologies, including battery and photoelectrochemical cell design. We propose an efficient and accurate approach to predict the electronic properties of aqueous solutions, on the basis of the combination of first-principles methods and experimental validation using state-of-the-art spectroscopic measurements. We present results of the photoelectron spectra of a broad range of solvated ions, showing that first-principles molecular dynamics simulations and electronic structure calculations using dielectric hybrid functionals provide a quantitative description of the electronic properties of the solvent and solutes, including excitation energies. The proposed computational framework is general and applicable to other liquids, thereby offering great promise in understanding and engineering solutions and liquid electrolytes for a variety of important energy technologies.

Electronic structure of aqueous solutions: Bridging the gap between theory and experiments

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

Pham, Tuan Anh; Govoni, Marco; Seidel, Robert

Predicting the electronic properties of aqueous liquids has been a long-standing challenge for quantum mechanical methods. However, it is a crucial step in understanding and predicting the key role played by aqueous solutions and electrolytes in a wide variety of emerging energy and environmental technologies, including battery and photoelectrochemical cell design. We propose an efficient and accurate approach to predict the electronic properties of aqueous solutions, on the basis of the combination of first-principles methods and experimental validation using state-of-the-art spectroscopic measurements. We present results of the photoelectron spectra of a broad range of solvated ions, showing that first-principles molecularmore » dynamics simulations and electronic structure calculations using dielectric hybrid functionals provide a quantitative description of the electronic properties of the solvent and solutes, including excitation energies. The proposed computational framework is general and applicable to other liquids, thereby offering great promise in understanding and engineering solutions and liquid electrolytes for a variety of important energy technologies.« less

Mercury removal from aqueous solutions by zinc cementation.

PubMed

Ku, Young; Wu, Ming-Huan; Shen, Yung-Shen

2002-01-01

The main purpose of this research is to study the addition effect of the surfactant and other operating factors on the treatment of wastewater containing mercury ions in aqueous solution by cementation with sacrificing metal, zinc. The removal of mercury ions from aqueous solutions by cementation of zinc powder was found to be a function of solution pH and temperature, amount of zinc, concentration of mercury ion, contact time and the addition of several organic surfactants. Cementation of mercury was shown to be a feasible process to achieve a very high degree of mercury removal over a broad operational range within a fairly reasonable contact time. The reaction rate is approximately first order with respect to the concentration of mercury ion in aqueous solution. Among the surfactants used in this study, only the presence of SDS, an anionic surfactant, slightly enhanced the cementation rate of mercury. The presence of CTAB and Triton-X100 retarded the cementation of mercury by zinc.

Self-Assembly of Porphyrin J-Aggregates

NASA Astrophysics Data System (ADS)

Snitka, Valentinas; Rackaitis, Mindaugas; Navickaite, Gintare

2006-03-01

The porphyrin nanotubes were built by ionic self-assembly of two oppositely charged porphyrins in aqueous solution. The porphyrins in the acid aqueous solution self-assemble into J-aggregates, wheels or other structures. The electrostatic forces between these porphyrin blocks contribute to the formation of porphyrin aggregates in the form of nanotubes, enhance the structural stability of these nanostructures. The nanotubes were composed mixing aqueous solutions of the two porphyrins - anionic Meso-tetra(4- sulfonatophrnyl)porhine dihydrochloride (TPPS4) and cationic Meso-tetra(4-pyridyl)porphine (T4MPyP). The porphyrin nanotubes obtained are hollow structures with the length of 300 nm and diameter 50 nm. Photocatalytic porphyrins are used to reduce metal complexes from aqueous solution and to control the deposition of Au from AuHCl4 and Au nanoparticles colloid solutions onto porphyrin nanotubes. Porphyrin nanotubes are shown to reduce metal complexes and deposit the metal selectively onto the inner or outer surface of the tubes, leading to nanotube-metal composite structures.

Challenges in analysis of high-molar mass dextrans: comparison of HPSEC, AsFlFFF and DOSY NMR spectroscopy.

PubMed

Maina, Ndegwa Henry; Pitkänen, Leena; Heikkinen, Sami; Tuomainen, Päivi; Virkki, Liisa; Tenkanen, Maija

2014-01-01

Dilute solutions of various dextran standards, a high-molar mass (HMM) commercial dextran from Leuconostoc spp., and HMM dextrans isolated from Weissella confusa and Leuconostoc citreum were analyzed with high-performance size-exclusion chromatography (HPSEC), asymmetric flow field-flow fractionation (AsFlFFF), and diffusion-ordered NMR spectroscopy (DOSY). HPSEC analyses were performed in aqueous and dimethyl sulfoxide (DMSO) solutions, while only aqueous solutions were utilized in AsFlFFF and DOSY. The study showed that all methods were applicable to dextran analysis, but differences between the aqueous and DMSO-based solutions were obtained for HMM samples. These differences were attributed to the presence of aggregates in aqueous solution that were less prevalent in DMSO. The study showed that DOSY provides an estimate of the size of HMM dextrans, though calibration standards may be required for each experimental set-up. To our knowledge, this is the first study utilizing these three methods in analyzing HMM dextrans. Copyright © 2013 Elsevier Ltd. All rights reserved.

Final product analysis in the e-beam and gamma radiolysis of aqueous solutions of metoprolol tartrate

NASA Astrophysics Data System (ADS)

Slegers, Catherine; Tilquin, Bernard

2006-09-01

The radiostability of metoprolol tartrate aqueous solutions and the influence of the absorbed dose (0-50 kGy), dose rate (e-beam (EB) vs. gamma ( γ)) and radioprotectors (pharmaceutical excipients) are investigated by HPLC-UV analyses and through computer simulations. The use of radioprotecting excipients is more promising than an increase in the dose rate to lower the degradation of metoprolol tartrate aqueous solutions for applications such as radiosterilization. The decontamination of metoprolol tartrate from waste waters by EB processing appears highly feasible.

Vibrational spectroscopic study of nickel (II) formate, Ni(HCO 2) 2, and its aqueous solution

NASA Astrophysics Data System (ADS)

Edwards, H. G. M.; Knowles, A.

1992-04-01

A vibrational spectroscopic study of nickel (II) formate and its aqueous solution has been made. The vibrations characteristic of a formato—nickel complex have been assigned and it is concluded that the species Ni(HCO 2) +(HCO 2) - exists in the solid state, with monodentate ligand-to-metal bonding. The Raman spectrum of an aqueous solution of nickel (II) formate indicates that complete dissociation of the formato—nickel (II) species occurs to formate ions and nickel (II) hexa-aquo ions. Comparisons are made with other nickel (II) carboxylates.

Selected specific rates of reactions of transients from water in aqueous solution. III. Hydroxyl radical and perhydroxyl radical and their radical ions

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

Ross, F; Ross, A B

1977-01-01

Rates of reactions of OH and HO/sub 2/ with organic and inorganic molecules, ions and transients in aqueous solution have been tabulated, as well as the rates for the corresponding radical ions in aqueous solution (O/sup -/ and O/sub 2//sup -/). Most of the rates have been obtained by radiation chemistry methods, both pulsed and steady-state; data from photochemistry and thermal methods are also included. Rates for over one thousand reactions are listed.

Measurements of Atmospheric Aerosols: Experimental Methods and Results of Measurements off the East Coast of the United States.

DTIC Science & Technology

1983-07-19

Pruppacher and Klett, 1978) 2(rl ’. r R 1 F5S = a,, e (5) where a. is the water activity of the aqueous solution , (r is the surface tension of the droplet...desorption) of ions by the insoluble portion of the particle, which is assumed to be totally submerged in the aqueous solution . We denote the coefficient ...between the saturation ratio S (relative humidity/100) of the air and the equili- brium radius r of an aqueous solution droplet may be expressed as

Patents – Melvin Calvin

Science.gov Websites

plutonium from uranium and fission products in an aqueous acidic solution by use of a chelating agent. The concentration is adjusted to about 1 N bar. The aqueous solution is then contacted with a water-immiscible organic solvent solution and the chelating agent. The chelating agents covered by this invention comprise

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

Bunkin, N F; Shkirin, A V; Burkhanov, I S

Aqueous NaCl solutions with different concentrations have been investigated by dynamic scattering of laser radiation. It is experimentally shown that these solutions contain scattering particles with a wide size distribution in a range of ∼10 – 100 nm. The experimental results indirectly confirm the existence of quasi-stable gas nanobubbles in the bulk of aqueous ionic solutions. (light scattering)

NMR studies of water dynamics during sol-to-gel transition of poly (N-isopropylacrylamide) in concentrated aqueous solution

USDA-ARS?s Scientific Manuscript database

The thermo-sensitive polymer, poly(N-isopropylacrylamide) (PNIPAM) undergoes a coil-to-globule transition in an aqueous solution as the temperature is raised through the lower critical solution temperature. Thus far, little is known about the dynamical states of the water molecules that contribute ...

METHOD FOR ELECTRODEPOSITING POLONIUM

DOEpatents

Wehrmann, R.F.

1960-08-30

The deposition of a thick uniform layer of polonium metal from aqueous solutions can be carried out by electrolyzing an aqueous solution of 1 N hydrofluoric acid containing about 0.13 curie of polonium per cubic centimeter of solution with platinum electrodes and a current density of about 1.2 ma/cm/sup 2/ of cathode surface.

MECHANISTIC ROLES OF SOIL HUMUS AND MINERALS IN THE SORPTION OF NONIONIC ORGANIC COMPOUNDS FROM AQUEOUS AND ORGANIC SOLUTIONS

EPA Science Inventory

Mechanistic roles of soil humus and soil minerals and their contributions to soil sorption of nonionic organic compounds from aqueous and organic solutions are illustrated. Parathion and lindane are used as model solutes on two soils that differ greatly in their humic and mineral...

CO2 as a smart gelator for Pluronic aqueous solutions.

PubMed

Liu, Chengcheng; Mei, Qingqing; Zhang, Jianling; Kang, Xinchen; Peng, Li; Han, Buxing; Xue, Zhimin; Sang, Xinxin; Yang, Xiaogan; Wu, Zhonghua; Li, Zhihong; Mo, Guang

2014-11-25

It was found that CO2 could induce the gelation of Pluronic aqueous solutions, during which the microstructure of the solution transforms from randomly dispersed spherical micelles to cubic close packed micelles. The gelation switched by compressed CO2 has many advantages and can be applied in the synthesis of porous materials.

Method for aqueous radioactive waste treatment

DOEpatents

Bray, L.A.; Burger, L.L.

1994-03-29

Plutonium, strontium, and cesium found in aqueous waste solutions resulting from nuclear fuel processing are removed by contacting the waste solutions with synthetic zeolite incorporating up to about 5 wt % titanium as sodium titanate in an ion exchange system. More than 99.9% of the plutonium, strontium, and cesium are removed from the waste solutions. 3 figures.

Method for aqueous radioactive waste treatment

DOEpatents

Bray, Lane A.; Burger, Leland L.

1994-01-01

Plutonium, strontium, and cesium found in aqueous waste solutions resulting from nuclear fuel processing are removed by contacting the waste solutions with synthetic zeolite incorporating up to about 5 wt % titanium as sodium titanate in an ion exchange system. More than 99.9% of the plutonium, strontium, and cesium are removed from the waste solutions.

Direct evidence on the existence of [Mo132]Keplerate-type species in aqueous solution.

PubMed

Roy, Soumyajit; Planken, Karel L; Kim, Robbert; Mandele, Dexx v d; Kegel, Willem K

2007-10-15

We demonstrate the existence of discrete single molecular [Mo(132)] Keplerate-type clusters in aqueous solution. Starting from a discrete spherical [Mo(132)] cluster, the formation of an open-basket-type [Mo(116)] defect structure is shown for the first time in solution using analytical ultracentrifugation sedimentation velocity experiments.

Solubilization of polycyclic aromatic hydrocarbons in micellar nonionic surfactant solutions

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

Edwards, D.A.; Luthy, R.G.; Liu, Zhongbao

1991-01-01

Experimental data are presented on the enhanced apparent solubilities of naphthalene, phenanthrene, and pyrene resulting from solubilization in aqueous solutions of four commercial, nonionic surfactants: an alkyl polyoxyethylene (POE) type, two octylphenol POE types, and a nonylphenol POE type. Apparent solubilities of the polycyclic aromatic hydrocarbon (PAH) compounds in surfactant solutions were determined by radiolabeled techniques. Solubilization of each PAH compound commenced at the surfactant critical micelle concentration and was proportional to the concentration of surfactant in micelle form. The partitioning of organic compounds between surfactant micelles and aqueous solution is characterized by a mole fraction micelle-phase/aqueous-phase partition coefficient, K{submore » m}. Values of log K{sub m} for PAH compounds in surfactant solutions of this study range from 4.57 to 6.53. Log K{sub m} appears to be a linear function of log K{sub ow} for a given surfactant solution. A knowledge of partitioning in aqueous surfactant systems is a prerequisite to understanding mechanisms affecting the behavior of hydrophobic organic compounds in soil-water systems in which surfactants play a role in contaminant remediation or facilitated transport.« less

Raman spectra of amino acids and their aqueous solutions

NASA Astrophysics Data System (ADS)

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

2011-03-01

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

STRIPPING OF URANIUM FROM ORGANIC EXTRACTANTS

DOEpatents

Crouse, D.J. Jr.

1962-09-01

A liquid-liquid extraction method is given for recovering uranium values from uranium-containing solutions. Uranium is removed from a uranium-containing organic solution by contacting said organic solution with an aqueous ammonium carbonate solution substantially saturated in uranium values. A uranium- containing precipitate is thereby formed which is separated from the organic and aqueous phases. Uranium values are recovered from this separated precipitate. (AE C)

PROCESS OF ELIMINATING HYDROGEN PEROXIDE IN SOLUTIONS CONTAINING PLUTONIUM VALUES

DOEpatents

Barrick, J.G.; Fries, B.A.

1960-09-27

A procedure is given for peroxide precipitation processes for separating and recovering plutonium values contained in an aqueous solution. When plutonium peroxide is precipitated from an aqueous solution, the supernatant contains appreciable quantities of plutonium and peroxide. It is desirable to process this solution further to recover plutonium contained therein, but the presence of the peroxide introduces difficulties; residual hydrogen peroxide contained in the supernatant solution is eliminated by adding a nitrite or a sulfite to this solution.

Piezoelectric Resonance Defined High Performance Sensors and Modulators

DTIC Science & Technology

2016-05-30

Lopez-Ribot, Amar S. Bhalla, Melissa Montes, Ruyan Guo. Properties of Silver and Copper Nanoparticle Containing Aqueous Suspensions and Evaluation of...Amar S. Bhalla, Ruyan Guo, “Properties of Silver and Copper Nanoparticle - Containing Aqueous Solutions and Their Anti-Biofilm Effects," (2015)Symposium...Properties of Silver and Copper Nanoparticle -Containing AqueousSolutions and Evaluation of their In Vitro Activity againstCandida albicans and

Kinetics of photobleaching of aqueous solutions of ricin agglutinin in the presence of guanidine chloride

NASA Astrophysics Data System (ADS)

Brandt, Nikolai N.; Chikishev, Andrey Y.

2002-05-01

Kinetics of background decay in Raman spectra of aqueous solutions of ricin agglutinin in the presence of guanidine chloride were measured. The differences in the kinetics of photobleaching are discussed.

Sorption of Ochratoxin A from Aqueous Solutions Using β-Cyclodextrin-Polyurethane Polymer

PubMed Central

Appell, Michael; Jackson, Michael A.

2012-01-01

The ability of a cyclodextrin-polyurethane polymer to remove ochratoxin A from aqueous solutions was examined by batch rebinding assays. The results from the aqueous binding studies were fit to two parameter models to gain insight into the interaction of ochratoxin A with the nanosponge material. The ochratoxin A sorption data fit well to the heterogeneous Freundlich isotherm model. The polymer was less effective at binding ochratoxin A in high pH buffer (9.5) under conditions where ochratoxin A exists predominantly in the dianionic state. Batch rebinding assays in red wine indicate the polymer is able to remove significant levels of ochratoxin A from spiked solutions between 1–10 μg·L−1. These results suggest cyclodextrin nanosponge materials are suitable to reduce levels of ochratoxin A from spiked aqueous solutions and red wine samples. PMID:22474569

Friction and Wear Modifiers Using Solvent Partitioning of Hydrophilic Surface-interactive Chemicals Contained in Boundary Layer-targeted Emulsions

NASA Technical Reports Server (NTRS)

Richmond, Robert Chafee (Inventor); Schramm, Jr., Harry F. (Inventor); Defalco, Francis G. (Inventor)

2013-01-01

A wear and/or friction reducing additive for a lubricating fluid in which the additive is a combination of a moderately hydrophilic single-phase compound and an anti-wear and/or anti-friction aqueous salt solution. The aqueous salt solution produces a coating on boundary layer surfaces. The lubricating fluid can be an emulsion-free hydrophobic oil, hydraulic fluid, antifreeze, or water. Preferably, the moderately hydrophilic single-phase compound is sulfonated castor oil and the aqueous salt solution additionally contains boric acid and zinc oxide. The emulsions produced by the aqueous salt solutions, the moderately hydrophilic single-phase compounds, or the combination thereof provide targeted boundary layer organizers that significantly enhance the anti-wear and/or anti-friction properties of the base lubricant by decreasing wear and/or friction of sliding and/or rolling surfaces at boundary layers.

Friction and Wear Modifiers Using Solvent Partitioning of Hydrophilic Surface-Interactive Chemicals Contained in Boundary Layer-Targeted Emulsions

NASA Technical Reports Server (NTRS)

Defalco, Francis G. (Inventor); Richmond, Robert Chaffee (Inventor); Schramm, Jr., Harry F. (Inventor)

2017-01-01

A wear and/or friction reducing additive for a lubricating fluid in which the additive is a combination of a moderately hydrophilic single-phase compound and an anti-wear and/or anti-friction aqueous salt solution. The aqueous salt solution produces a coating on boundary layer surfaces. The lubricating fluid can be an emulsion-free hydrophobic oil, hydraulic fluid, antifreeze, water, or a water-based lubricant. Preferably, the moderately hydrophilic single-phase compound is sulfonated castor oil and the aqueous salt solution additionally contains boric acid and zinc oxide. The emulsions produced by the aqueous salt solutions, the moderately hydrophilic single-phase compounds, or the combination thereof provide targeted boundary layer organizers that significantly enhance the anti-wear and/or anti-friction properties of the base lubricant by decreasing wear and/or friction of sliding and/or rolling surfaces at boundary layers.

Friction and Wear Modifiers Using Solvent Partitioning of Hydrophilic Surface-Interactive Chemicals Contained in Boundary Layer-Targeted Emulsions

NASA Technical Reports Server (NTRS)

Defalco, Francis G. (Inventor); Richmond, Robert Chaffee (Inventor); Schramm, Harry F., Jr. (Inventor)

2016-01-01

A wear and/or friction reducing additive for a lubricating fluid in which the additive is a combination of a moderately hydrophilic single-phase compound and an anti-wear and/or anti-friction aqueous salt solution. The aqueous salt solution produces a coating on boundary layer surfaces. The lubricating fluid can be an emulsion-free hydrophobic oil, hydraulic fluid, antifreeze, or water. Preferably, the moderately hydrophilic single-phase compound is sulfonated castor oil and the aqueous salt solution additionally contains boric acid and zinc oxide. The emulsions produced by the aqueous salt solutions, the moderately hydrophilic single-phase compounds, or the combination thereof provide targeted boundary layer organizers that significantly enhance the anti-wear and/or anti-friction properties of the base lubricant by decreasing wear and/or friction of sliding and/or rolling surfaces at boundary layers.

Strengthening of the Coordination Shell by Counter Ions in Aqueous Th 4+ Solutions

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

Atta-Fynn, Raymond; Bylaska, Eric J.; de Jong, Wibe A.

The presence of counter ions in solutions containing highly charged metal cations can trigger processes such as ion-pair formation, hydrogen bond breakages and subsequent reformation, and ligand exchanges. In this work, it is shown how halide (Cl-, Br-) and perchlorate (ClO4-) anions affect the strength of the primary solvent coordination shells around Th4+ using explicit solvent and finite temperature ab initio molecular dynamics modeling methods. The 9-fold solvent geometry was found to be the most stable hydration structure in each aqueous solution. Relative to the dilute aqueous solution, the presence of the counter ions did not significantly alter the geometrymore » of the primary hydration shell. However, the free energy analyses indicated that the 10-fold hydrated states were thermodynamically accessible in dilute and bromide aqueous solutions within 1 kcal/mol. Analysis of the results showed that the hydrogen bond lifetimes were longer and solvent exchange energy barriers were larger in solutions with counter ions in comparison with the solution with no counter ions. This implies that the presence of the counter ions induces a strengthening of the Th4+ hydration shell.« less

Direct NMR Monitoring of Phase Separation Behavior of Highly Supersaturated Nifedipine Solution Stabilized with Hypromellose Derivatives.

PubMed

Ueda, Keisuke; Higashi, Kenjirou; Moribe, Kunikazu

2017-07-03

We investigated the phase separation behavior and maintenance mechanism of the supersaturated state of poorly water-soluble nifedipine (NIF) in hypromellose (HPMC) derivative solutions. Highly supersaturated NIF formed NIF-rich nanodroplets through phase separation from aqueous solution containing HPMC derivative. Dissolvable NIF concentration in the bulk water phase was limited by the phase separation of NIF from the aqueous solution. HPMC derivatives stabilized the NIF-rich nanodroplets and maintained the NIF supersaturation with phase-separated NIF for several hours. The size of the NIF-rich phase was different depending on the HPMC derivatives dissolved in aqueous solution, although the droplet size had no correlation with the time for which NIF supersaturation was maintained without NIF crystallization. HPMC acetate and HPMC acetate succinate (HPMC-AS) effectively maintained the NIF supersaturation containing phase-separated NIF compared with HPMC. Furthermore, HPMC-AS stabilized NIF supersaturation more effectively in acidic conditions. Solution 1 H NMR measurements of NIF-supersaturated solution revealed that HPMC derivatives distributed into the NIF-rich phase during the phase separation of NIF from the aqueous solution. The hydrophobicity of HPMC derivative strongly affected its distribution into the NIF-rich phase. Moreover, the distribution of HPMC-AS into the NIF-rich phase was promoted at lower pH due to the lower aqueous solubility of HPMC-AS. The distribution of a large amount of HPMC derivatives into NIF-rich phase induced the strong inhibition of NIF crystallization from the NIF-rich phase. Polymer distribution into the drug-rich phase directly monitored by solution NMR technique can be a useful index for the stabilization efficiency of drug-supersaturated solution containing a drug-rich phase.

Rotational dynamics of trehalose in aqueous solutions studied by depolarized light scattering

NASA Astrophysics Data System (ADS)

Gallina, M. E.; Comez, L.; Morresi, A.; Paolantoni, M.; Perticaroli, S.; Sassi, P.; Fioretto, D.

2010-06-01

High resolution depolarized light scattering spectra, extended from 0.5 to 2×104 GHz by the combined used of a dispersive and an interferometric setup, give evidence of separated solute and solvent dynamics in diluted trehalose aqueous solutions. The slow relaxation process, located in the gigahertz frequency region, is analyzed as a function of temperature and concentration and assigned to the rotational diffusion of the sugar molecule. The results are discussed in comparison with the data obtained on glucose solutions and they are used to clarify the molecular origin of some among the several relaxation processes reported in literature for oligosaccharides solutions. The concentration dependence of relaxation time and of shear viscosity are also discussed, suggesting that the main effect of carbohydrate molecules on the structural relaxation of diluted aqueous solutions is the perturbation induced on the dynamics of the first hydration shell of each solute molecule.

Process for the combined removal of SO.sub.2 and NO.sub.x from flue gas

DOEpatents

Chang, Shih-Ger; Liu, David K.; Griffiths, Elizabeth A.; Littlejohn, David

1988-01-01

The present invention in one aspect relates to a process for the simultaneous removal of NO.sub.x and SO.sub.2 from a fluid stream comprising mixtures thereof and in another aspect relates to the separation, use and/or regeneration of various chemicals contaminated or spent in the process and which includes the steps of: (A) contacting the fluid stream at a temperature of between about 105.degree. and 180.degree. C. with a liquid aqueous slurry or solution comprising an effective amount of an iron chelate of an amino acid moiety having at least one --SH group; (B) separating the fluid stream from the particulates formed in step (A) comprising the chelate of the amino acid moiety and fly ash; (C) washing and separating the particulates of step (B) with an aqueous solution having a pH value of between about 5 to 8; (D) subsequently washing and separating the particulates of step (C) with a strongly acidic aqueous solution having a pH value of between about 1 to 3; (E) washing and separating the particulates of step (D) with an basic aqueous solution having a pH value of between about 9 to 12; (F) optionally adding additional amino acid moiety, iron (II) and alkali to the aqueous liquid from step (D) to produce an aqueous solution or slurry similar to that in step (A) having a pH value of between about 4 to 12; and (G) recycling the aqueous slurry of step (F) to the contacting zone of step (A). Steps (D) and (E) can be carried out in the reverse sequence, however the preferred order is (D) and then (E). In another preferred embodiment the present invention provides a process for the removal of NO.sub.x, SO.sub.2 and particulates from a fluid stream which includes the steps of (A) injecting into a reaction zone an aqueous solution itself comprising (i) an amino acid moiety selected from those described above; (ii) iron (II) ion; and (iii) an alkali, wherein the aqueous solution has a pH of between about 4 and 11; followed by solids separation and washing as is described in steps (B), (C), (D) and (E) above. The overall process is useful to reduce acid rain components from combustion gas sources.

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

PubMed

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

2012-02-16

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

DISSOLUTION OF LANTHANUM FLUORIDE PRECIPITATES

DOEpatents

Fries, B.A.

1959-11-10

A plutonium separatory ore concentration procedure involving the use of a fluoride type of carrier is presented. An improvement is given in the derivation step in the process for plutonium recovery by carrier precipitation of plutonium values from solution with a lanthanum fluoride carrier precipitate and subsequent derivation from the resulting plutonium bearing carrier precipitate of an aqueous acidic plutonium-containing solution. The carrier precipitate is contacted with a concentrated aqueous solution of potassium carbonate to effect dissolution therein of at least a part of the precipitate, including the plutonium values. Any remaining precipitate is separated from the resulting solution and dissolves in an aqueous solution containing at least 20% by weight of potassium carbonate. The reacting solutions are combined, and an alkali metal hydroxide added to a concentration of at least 2N to precipitate lanthanum hydroxide concomitantly carrying plutonium values.

Sorption of tetracycline antibiotics on hyper-crosslinked polystyrene from aqueous and aqueous-organic media

NASA Astrophysics Data System (ADS)

Udalova, A. Yu.; Dmitrienko, S. G.; Apyari, V. V.

2015-06-01

The sorption of tetracycline, oxytetracycline, chlortetracycline, and doxycycline on hyper-cross-linked polystyrene from aqueous and aqueous-organic solutions is studied under static and dynamic conditions in order to extend the range of the sorbents suitable for sorption isolation and the preconcentration of tetracycline antibiotics. Features of tetracycline sorption depending on the acidity of a solution and the nature and concentration of the compounds are explained. It is shown that hyper-crosslinked polystyrene can be used for the group sorption preconcentration of these compounds.

NEPTUNIUM SOLVENT EXTRACTION PROCESS

DOEpatents

Dawson, L.R.; Fields, P.R.

1959-10-01

The separation of neptunium from an aqueous solution by solvent extraction and the extraction of neptunium from the solvent solution are described. Neptunium is separated from an aqueous solution containing tetravalent or hexavalent neptunium nitrate, nitric acid, and a nitrate salting out agent, such as sodium nitrate, by contacting the solution with an organic solvent such as diethyl ether. Subsequently, the neptunium nitrate is extracted from the organic solvent extract phase with water.

The effect of deep eutectic solvents on catalytic function and structure of bovine liver catalase.

PubMed

Harifi-Mood, Ali Reza; Ghobadi, Roohollah; Divsalar, Adeleh

2017-02-01

Aqueous solutions of reline and glyceline, the most common deep eutectic solvents, were used as a medium for Catalase reaction. By some spectroscopic methods such as UV-vis, fluorescence and circular dichroism (CD) function and structure of Catalase were investigated in aqueous solutions of reline and glyceline. These studies showed that the binding affinity of the substrate to the enzyme increased in the presence of 100mM glyceline solution, which contrasts with reline solution that probably relates to instructive changes in secondary structure of protein. Meanwhile, enzyme remained nearly 70% and 80% active in this concentration of glyceline and reline solutions respectively. In the high concentration of DES solutions, enzyme became mainly inactive but surprisingly stayed in nearly 40% active in choline chloride solution, which is the common ion species in reline and glyceline solvents. It is proposed that the chaotropic nature of choline cation might stop the reducing trend of activity in concentrated choline chloride solutions but this instructive effect is lost in aqueous deep eutectic solvents. In this regard, the presence of various concentrations of deep eutectic solvents in the aqueous media of human cells would be an activity adjuster for this important enzyme in its different operation conditions. Copyright © 2016 Elsevier B.V. All rights reserved.

Hydration and dielectrical properties of aqueous pyrrolidinium trifluoroacetate solutions

NASA Astrophysics Data System (ADS)

Lyashchenko, A. K.; Balakaeva, I. V.; Simonova, Yu. A.; Timofeeva, L. M.

2017-10-01

Results from microwave measurements of the dielectrical properties of aqueous pyrrolidinium trifluoroacetate solutions at maximum water dispersion frequencies (13-25 GHz) and temperatures of 288, 298, and 308 K are given. The static dielectrical constants, times, and activation parameters of the dielectrical relaxation of solutions are calculated. The enthalpy and time of dielectrical relaxation activation are increased by deceleration of the motion of water molecules in the hydrate shells of ions. The changes in dielectrical parameters are in this case minimal in a series of aqueous solutions of diallylammonium salts with cations of different structures and degrees of substitution. It is shown that pyrrolidinium ions are characterized by weak hydrophobic hydration.

Marangoni Flow Induced Evaporation Enhancement on Binary Sessile Drops.

PubMed

Chen, Pin; Harmand, Souad; Ouenzerfi, Safouene; Schiffler, Jesse

2017-06-15

The evaporation processes of pure water, pure 1-butanol, and 5% 1-butanol aqueous solution drops on heated hydrophobic substrates are investigated to determine the effect of temperature on the drop evaporation behavior. The evolution of the parameters (contact angle, diameter, and volume) during evaporation measured using a drop shape analyzer and the infrared thermal mapping of the drop surface recorded by an infrared camera were used in investigating the evaporation process. The pure 1-butanol drop does not show any thermal instability at different substrate temperatures, while the convection cells created by the thermal Marangoni effect appear on the surface of the pure water drop from 50 °C. Because 1-butanol and water have different surface tensions, the infrared video of the 5% 1-butanol aqueous solution drop shows that the convection cells are generated by the solutal Marangoni effect at any substrate temperature. Furthermore, when the substrate temperature exceeds 50 °C, coexistence of the thermal and solutal Marangoni flows is observed. By analyzing the relation between the ratio of the evaporation rate of pure water and 1-butanol aqueous solution drops and the Marangoni number, a series of empirical equations for predicting the evaporation rates of pure water and 1-butanol aqueous solution drops at the initial time as well as the equations for the evaporation rate of 1-butanol aqueous solution drop before the depletion of alcohol are derived. The results of these equations correspond fairly well to the experimental data.

METHOD OF SEPARATING PLUTONIUM

DOEpatents

Heal, H.G.

1960-02-16

BS>A method of separating plutonium from aqueous nitrate solutions of plutonium, uranium. and high beta activity fission products is given. The pH of the aqueous solution is adjusted between 3.0 to 6.0 with ammonium acetate, ferric nitrate is added, and the solution is heated to 80 to 100 deg C to selectively form a basic ferric plutonium-carrying precipitate.

Cesium recovery from aqueous solutions

DOEpatents

Goodhall, C. A.

1960-09-13

A process for recovering cesium from aqueous solutions is given in which precipitation on zinc ferricyanide is used. The precipitation is preferably carried out in solutions containing at least 0.0004M zinc ferricyanide, an acidity ranging from 0.2N mineral acid to 0.61N acid deficiency, and 1 to 2.5M aluminum nitrate. (D.L.C.)

Thermodynamic studies of aqueous solutions of 2,2,2-cryptand at 298.15 K: enthalpy-entropy compensation, partial entropies, and complexation with K+ ions.

PubMed

Shaikh, Vasim R; Terdale, Santosh S; Ahamad, Abdul; Gupta, Gaurav R; Dagade, Dilip H; Hundiwale, Dilip G; Patil, Kesharsingh J

2013-12-19

The osmotic coefficient measurements for binary aqueous solutions of 2,2,2-cryptand (4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8] hexacosane) in the concentration range of ~0.009 to ~0.24 mol·kg(-1) and in ternary aqueous solutions containing a fixed concentration of 2,2,2-cryptand of ~0.1 mol·kg(-1) with varying concentration of KBr (~0.06 to ~0.16 mol·kg(-1)) have been reported at 298.15 K. The diamine gets hydrolyzed in aqueous solutions and needs proper approach to obtain meaningful thermodynamic properties. The measured osmotic coefficient values are corrected for hydrolysis and are used to determine the solvent activity and mean ionic activity coefficients of solute as a function of concentration. Strong ion-pair formation is observed, and the ion-pair dissociation constant for the species [CrptH](+)[OH(-)] is reported. The excess and mixing thermodynamic properties (Gibbs free energy, enthalpy, and entropy changes) have been obtained using the activity data from this study and the heat data reported in the literature. Further, the data are utilized to compute the partial molal entropies of solvent and solute at finite as well as infinite dilution of 2,2,2-cryptand in water. The concentration dependent non-linear enthalpy-entropy compensation effect has been observed for the studied system, and the compensation temperature along with entropic parameter are reported. Using solute activity coefficient data in ternary solutions, the transfer Gibbs free energies for transfer of the cryptand from water to aqueous KBr as well as transfer of KBr from water to aqueous cryptand were obtained and utilized to obtain the salting constant (ks) and thermodynamic equilibrium constant (log K) values for the complex (2,2,2-cryptand:K(+)) at 298.15 K. The value of log K = 5.8 ± 0.1 obtained in this work is found to be in good agreement with that reported by Lehn and Sauvage. The standard molar entropy for complexation is also estimated for the 2,2,2-cryptand-KBr complex in aqueous medium.

Separations by supported liquid membrane cascades

DOEpatents

Danesi, P.R.

1983-09-01

The invention describes a new separation technique which leads to multi-stage operations by the use of a series (a cascade) of alternated carrier-containing supported-liquid cation exchanger extractant and a liquid anion exchanger extractant (or a neutral extractant) as carrier. The membranes are spaced between alternated aqueous electrolytic solutions of different composition which alternatively provide positively charged extractable species and negatively charged (or zero charged) extractable species, of the chemical species to be separated. The alternated aqueous electrolytic solutions in addition to providing the driving force to the process, simultaneously function as a stripping solution from one type of membrane and as an extraction-promoting solution for the other type of membrane. The aqueous electrolytic solution and the supported liquid membranes are arranged to provide a continuous process.

Quenching characteristics of bathocuproinedisulfonic acid, disodium salt in aqueous solution and copper sulfate plating solution

NASA Astrophysics Data System (ADS)

Koga, Toshiaki; Hirakawa, Chieko; Takeshita, Michinori; Terasaki, Nao

2018-04-01

Bathocuproinedisulfonic acid, disodium salt (BCS) is generally used to detect Cu(I) through a color reaction. We newly found BCS fluorescence in the visible blue region in an aqueous solution. However, the fluorescence mechanism of BCS is not well known, so we should investigate its fundamental information. We confirmed that the characteristics of fluorescence are highly dependent on the molecular concentration and solvent properties. In particular, owing to the presence of the copper compound, the fluorescence intensity extremely decreases. By fluorescence quenching, we observed that a copper compound concentration of 10-6 mol/L or less could easily be measured in an aqueous solution. We also observed BCS fluorescence in copper sulfate plating solution and the possibility of detecting monovalent copper by fluorescence reabsorption.

DISTRIBUTION OF URANIUM, ZIRCONIUM, NIOBIUM, RUTHENIUM AND CERIUM BETWEEN NITRIC ACID SOLUTIONS AND 10% TLA-5% OCTYL ALCOHOL/SHELL SOL-T

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

Lopez-Menchero, E.; Centeno, J.; Magni, G.

1962-03-01

The extraction of traces of Ru, Zr, Nb, Ce, and U at low concentrations (5 mg/l in aqueous solution) from nitric acid solutions using trilauryl amine (TLA) has been experimentally studied. TLA will eventually be used for final purification of plutonium. Room-temperature data on plutonium contaminant distribution between aqueous solutions of varying nitric acid concentrations and a Shellsol-T solution containing l0% TlA and 5% octyl alcohol are presented. Within the temperature and nitric acid concentration ranges tested, the extractability of uranium increased with increased acid concentrations, although acid concentration in the aqueous phase had no effect on the decontamination factorsmore » for the main fission products. (H.G.G.)« less

End-Member Formulation of Solid Solutions and Reactive Transport

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

Lichtner, Peter C.

2015-09-01

A model for incorporating solid solutions into reactive transport equations is presented based on an end-member representation. Reactive transport equations are solved directly for the composition and bulk concentration of the solid solution. Reactions of a solid solution with an aqueous solution are formulated in terms of an overall stoichiometric reaction corresponding to a time-varying composition and exchange reactions, equivalent to reaction end-members. Reaction rates are treated kinetically using a transition state rate law for the overall reaction and a pseudo-kinetic rate law for exchange reactions. The composition of the solid solution at the onset of precipitation is assumed tomore » correspond to the least soluble composition, equivalent to the composition at equilibrium. The stoichiometric saturation determines if the solid solution is super-saturated with respect to the aqueous solution. The method is implemented for a simple prototype batch reactor using Mathematica for a binary solid solution. Finally, the sensitivity of the results on the kinetic rate constant for a binary solid solution is investigated for reaction of an initially stoichiometric solid phase with an undersaturated aqueous solution.« less

Thin film superconductors and process for making same

DOEpatents

Nigrey, P.J.

1988-01-21

A process for the preparation of oxide superconductors from high-viscosity non-aqueous solution is described. Solutions of lanthanide nitrates, alkaline earth nitrates and copper nitrates in a 1:2:3 stoichiometric ratio, when added to ethylene glycol containing citric acid solutions, have been used to prepare highly viscous non-aqueous solutions of metal mixed nitrates-citrates. Thin films of these compositions are produced when a layer of the viscous solution is formed on a substrate and subjected to thermal decomposition.

CONTINUOUS CHELATION-EXTRACTION PROCESS FOR THE SEPARATION AND PURIFICATION OF METALS

DOEpatents

Thomas, J.R.; Hicks, T.E.; Rubin, B.; Crandall, H.W.

1959-12-01

A continuous process is presented for separating metal values and groups of metal values from each other. A complex mixture. e.g., neutron-irradiated uranium, can be resolved into component parts. In the present process the values are dissolved in an acidic solution and adjusted to the proper oxidation state. Thenceforth the solution is contacted with an extractant phase comprising a fluorinated beta -diketone in an organic solvent under centain pH conditions whereupon plutonium and zirconium are extracted. Plutonium is extracted from the foregoing extract with reducing aqueous solutions or under specified acidic conditions and can be recovered from the aqueous solution. Zirconium is then removed with an oxalic acid aqueous phase. The uranium is recovered from the residual original solution using hexone and hexone-diketone extractants leaving residual fission products in the original solution. The uranium is extracted from the hexone solution with dilute nitric acid. Improved separations and purifications are achieved using recycled scrub solutions and the "self-salting" effect of uranyl ions.

METHOD OF REDUCING PLUTONIUM COMPOUNDS

DOEpatents

Johns, I.B.

1958-06-01

A method is described for reducing plutonium compounds in aqueous solution from a higher to a lower valence state. This reduction of valence is achieved by treating the aqueous solution of higher valence plutonium compounds with hydrogen in contact with an activated platinum catalyst.

SURFACE TREATMENT OF MOLYBDENUM METAL

DOEpatents

Coffer, C.O.

1961-12-01

A process of descaling molybdenum articles comprises first immersing them in an aqueous sodium hydroxide-potassium permanganate solution of between 60 and 85 deg C, rinsing, and then immersing them in an aqueous solution containing a mixture of sulfuric, hydrochloric, and chromic acids.

PHOTOREACTION OF VALEROPHENONE IN AQUEOUS SOLUTION

EPA Science Inventory

Kinetics and products of the photoreaction of the phenyl ketone valerophenone were investigated as a function of temperature, pH, and wavelength in aqueous solution. Under these conditions (<10-4M), the photoreactions are pseudo-first-order with respect to valerophenone concentra...

Investigation into the temporal stability of aqueous standard solutions of psilocin and psilocybin using high performance liquid chromatography.

PubMed

Anastos, N; Barnett, N W; Pfeffer, F M; Lewis, S W

2006-01-01

This paper reports an investigation into the temporal stability of aqueous solutions of psilocin and psilocybin reference drug standards over a period of fourteen days. This study was performed using high performance liquid chromatography utilising a (95:5% v/v) methanol: 10 mM ammonium formate, pH 3.5 mobile phase and absorption detection at 269 nm. It was found that the exclusion of light significantly prolonged the useful life of standards, with aqueous solutions of both psilocin and psilocybin being stable over a period of seven days.

Fabrication of metal nanoshells

NASA Technical Reports Server (NTRS)

Kim, Jae-Woo (Inventor); King, Glen C. (Inventor); Lillehei, Peter T. (Inventor); Park, Yeonjoon (Inventor); Elliott, Jr., James R. (Inventor); Choi, Sang H. (Inventor); Chu, Sang-Hyon (Inventor)

2012-01-01

Metal nanoshells are fabricated by admixing an aqueous solution of metal ions with an aqueous solution of apoferritin protein molecules, followed by admixing an aqueous solution containing an excess of an oxidizing agent for the metal ions. The apoferritin molecules serve as bio-templates for the formation of metal nanoshells, which form on and are bonded to the inside walls of the hollow cores of the individual apoferritin molecules. Control of the number of metal atoms which enter the hollow core of each individual apoferritin molecule provides a hollow metal nonparticle, or nanoshell, instead of a solid spherical metal nanoparticle.

Enthalpies of Dissolution of Crystalline Naproxen Sodium in Water and Potassium Hydroxide Aqueous Solutions at 298 K

NASA Astrophysics Data System (ADS)

Lytkin, A. I.; Chernikov, V. V.; Krutova, O. N.; Bychkova, S. A.; Volkov, A. V.; Skvortsov, I. A.

2018-03-01

The enthalpies of dissolution of crystalline naproxen sodium in water and aqueous solutions of KOH at 298.15 K are measured by direct calorimetric means in a wide range of concentrations. The acid-base properties of naproxen sodium at ionic strength I 0 and I = 0.1 (KNO3) and a temperature of 298.15 K are studied by spectrophotometric means. The concentration and thermodynamic dissociation constants are determined. The standard enthalpies of the formation of naproxen sodium and the products of its dissociation in aqueous solution are calculated.

Solubility of mixtures of hydrogen sulfide and carbon dioxide in aqueous N-methyldiethanolamine solutions

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

Jou, Fang Yuan; Carroll, J.J.; Mather, A.E.

1993-01-01

Aqueous solutions of alkanolamines are commonly used to strip acid gases (H[sub 2]S and CO[sub 2]) from streams contaminated with these components. The two most widely used amines are monoethanolamine (MEA) and diethanolamine (DEA). The solubilities of mixtures of hydrogen sulfide and carbon dioxide in a 35 wt% (3.04 kmol/m[sup 3]) aqueous solution of N-methyldiethanolamine at 40 and 100C have been measured. Partial pressures of the acid gases ranged from 0.006 to 101 kPa at 40C and from 4 to 530 kPa at 100C.

Ultrasensitive molecular detection using thermal conductance of a hydrophobic gold-water interface.

PubMed

Green, Andrew J; Alaulamie, Arwa A; Baral, Susil; Richardson, Hugh H

2013-09-11

The thermal conductance from a hydrophobic gold aqueous interface is measured with increasing solute concentration. A small amount of aqueous solute molecules (1 solute molecule in 550 water molecules) dramatically increases the heat dissipation into the surrounding liquid. This result is consistent with a thermal conductance that is limited by an interface interaction where minority aqueous components significantly alter the surface properties and heat transport through the interface. The increase in heat dissipation can be used to make an extremely sensitive molecular detector that can be scaled to give single molecule detection without amplification or utilizing fluorescence labels.

Simplified Production of Organic Compounds Containing High Enantiomer Excesses

NASA Technical Reports Server (NTRS)

Cooper, George W. (Inventor)

2015-01-01

The present invention is directed to a method for making an enantiomeric organic compound having a high amount of enantiomer excesses including the steps of a) providing an aqueous solution including an initial reactant and a catalyst; and b) subjecting said aqueous solution simultaneously to a magnetic field and photolysis radiation such that said photolysis radiation produces light rays that run substantially parallel or anti-parallel to the magnetic field passing through said aqueous solution, wherein said catalyst reacts with said initial reactant to form the enantiomeric organic compound having a high amount of enantiomer excesses.

Quantum Chemical Simulation of the Interaction of Functional Groups in Polyurethanes with 3 d-Metal Ions During Their Extraction from Aqueous Solutions

NASA Astrophysics Data System (ADS)

Ksenofontov, M. A.; Bobkova, E. Yu.; Shundalau, M. B.; Ostrovskaya, L. E.; Vasil'eva, V. S.

2017-11-01

The interaction of the functional groups in the polyurethane foam adsorbent Penopurm® with the cations of some 3d-metals upon their extraction from aqueous solutions has been studied by atomic emission spectroscopy, UV/Vis and vibrational IR spectroscopy, and quantum chemical simulation using density functional theory. Penopurm® absorbs 3d-metal cations from aqueous solutions in the pH range 5-7. Some spectral criteria have been found indicating a predominant interaction of Ni2+ ions with various fragments of the polyurethane foam structure.

Micelle formation of nonionic surfactants in a room temperature ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate: surfactant chain length dependence of the critical micelle concentration.

PubMed

Inoue, Tohru; Yamakawa, Haruka

2011-04-15

Micellization behavior was investigated for polyoxyethylene-type nonionic surfactants with varying chain length (C(n)E(m)) in a room temperature ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF(4)). Critical micelle concentration (cmc) was determined from the variation of (1)H NMR chemical shift with the surfactant concentration. The logarithmic value of cmc decreased linearly with the number of carbon atoms in the surfactant hydrocarbon chain, similarly to the case observed in aqueous surfactant solutions. However, the slope of the straight line is much smaller in bmimBF(4) than in aqueous solution. Thermodynamic parameters for micelle formation estimated from the temperature dependence of cmc showed that the micellization in bmimBF(4) is an entropy-driven process around room temperature. This behavior is also similar to the case in aqueous solution. However, the magnitude of the entropic contribution to the overall micellization free energy in bmimBF(4) is much smaller compared with that in aqueous solution. These results suggest that the micellization in bmimBF(4) proceeds through a mechanism similar to the hydrophobic interaction in aqueous surfactant solutions, although the solvophobic effect in bmimBF(4) is much weaker than the hydrophobic effect. Copyright © 2011 Elsevier Inc. All rights reserved.

Hierarchical viscosity of aqueous solution of tilapia scale collagen investigated via dielectric spectroscopy between 500 MHz and 2.5 THz

PubMed Central

Kawamata, H.; Kuwaki, S.; Mishina, T.; Ikoma, T.; Tanaka, J.; Nozaki, R.

2017-01-01

Aqueous solutions of biomolecules such as proteins are very important model systems for understanding the functions of biomolecules in actual life processes because interactions between biomolecules and the surrounding water molecules are considered to be important determinants of biomolecules’ functions. Globule proteins have been extensively studied via dielectric spectroscopy; the results indicate three relaxation processes originating from fluctuations in the protein molecule, the bound water and the bulk water. However, the characteristics of aqueous solutions of collagens have rarely been investigated. In this work, based on broadband dielectric measurements between 500 MHz and 2.5 THz, we demonstrate that the high viscosity of a collagen aqueous solution is due to the network structure being constructed of rod-like collagen molecules surrounding free water molecules and that the water molecules are not responsible for the viscosity. We determine that the macroscopic viscosity is related to the mean lifetime of the collagen-collagen interactions supporting the networks and that the local viscosity of the water surrounded by the networks is governed by the viscosity of free water as in the bulk. This hierarchical structure in the dynamics of the aqueous solution of biomolecules has been revealed for the first time. PMID:28345664

SEPARATION OF PLUTONIUM VALUES FROM OTHER METAL VALUES IN AQUEOUS SOLUTIONS BY SELECTIVE COMPLEXING AND ADSORPTION

DOEpatents

Beaton, R.H.

1960-06-28

A process is given for separating tri- or tetravalent plutonium from fission products in an aqueous solution by complexing the fission products with oxalate, tannate, citrate, or tartrate anions at a pH value of at least 2.4 (preferably between 2.4 and 4), and contacting a cation exchange resin with the solution whereby the plutonium is adsorbed while the complexed fission products remain in solution.

The prediction of the flash point for binary aqueous-organic solutions.

PubMed

Liaw, Horng-Jang; Chiu, Yi-Yu

2003-07-18

A mathematical model, which may be used for predicting the flash point of aqueous-organic solutions, has been proposed and subsequently verified by experimentally-derived data. The results reveal that this model is able to precisely predict the flash point over the entire composition range of binary aqueous-organic solutions by way of utilizing the flash point data pertaining to the flammable component. The derivative of flash point with respect to composition (solution composition effect upon flash point) can be applied to process safety design/operation in order to identify as to whether the dilution of a flammable liquid solution with water is effective in reducing the fire and explosion hazard of the solution at a specified composition. Such a derivative equation was thus derived based upon the flash point prediction model referred to above and then verified by the application of experimentally-derived data.

Topical drug delivery to the eye: dorzolamide.

PubMed

Loftsson, Thorsteinn; Jansook, Phatsawee; Stefánsson, Einar

2012-11-01

Topically applied carbonic anhydrase inhibitors (CAIs) in eye drop solutions are commonly used to treat glaucoma. However, local eye irritation and multiple daily administrations may hamper their clinical usefulness. Aqueous eye drop formulations that improve their topical bioavailability and reduce their eye irritation can improve their clinical efficacy. Earlier studies showed that dorzolamide and closely related CAIs are more effectively delivered into the eye from acidic eye drop solutions than from comparable neutral solutions. Consequently, dorzolamide was marketed as an aqueous pH 5.6 eye drop solution (Trusopt(®) , Merck). Later, it was shown that increasing the pH of the eye drops from pH 5.6 to physiologic pH significantly reduced their local irritation. Earlier attempts to use cyclodextrins (CDs) as ocular penetration enhancers in dorzolamide eye drop solutions failed since; although the CDs were able to enhance the aqueous solubility of dorzolamide, increasing the pH from 5.6 to physiologic pH reduced the ability of the drug to permeate into the eye. Later, it was discovered that formulating the drug as aqueous dorzolamide/γCD eye drop microparticle suspension resulted in significant bioavailability enhancement. The solid dorzolamide/γCD microparticles are mucoadhesive and release dorzolamide into the aqueous tear fluid for extended time period. Consequently, sustained high dorzolamide concentrations in aqueous humour and various eye tissues were observed after single administration of the aqueous dorzolamide/γCD eye drop microsuspension. The microsuspension has a potential of being developed into a once-a-day eye drop product. This article reviews the physicochemical properties of dorzolamide, its permeation characteristics and topical bioavailability. © 2012 The Authors. Acta Ophthalmologica © 2012 Acta Ophthalmologica Scandinavica Foundation.

Acidities of Water and Methanol in Aqueous Solution and DMSO

ERIC Educational Resources Information Center

Gao, Daqing

2009-01-01

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

Effects of Metal Ions on Viscosity of Aqueous Sodium Carboxylmethylcellulose Solution and Development of Dropping Ball Method on Viscosity

ERIC Educational Resources Information Center

Set, Seng; Ford, David; Kita, Masakazu

2015-01-01

This research revealed that metal ions with different charges could significantly affect the viscosity of aqueous sodium carboxylmethylcellulose (CMC) solution. On the basis of an Ostwald viscometer, an improvised apparatus using a dropping ball for examining the viscosity of liquids/solutions has been developed. The results indicate that the…

Evaluation of the antibacterial activity of a cationic polymer in aqueous solution with a convenient electrochemical method.

PubMed

Wang, Yihong; Guo, Qing; Wang, Huafu; Qian, Kun; Tian, Liang; Yao, Chen; Song, Wei; Shu, Weixia; Chen, Ping; Qi, Jinxu

2017-02-01

Quaternized chitosan is a cationic biopolymer with good antibacterial activity, biocompatibility, and biodegradability, and it has been widely applied in many fields. We have developed a convenient method to evaluate the antibacterial activity of hydroxypropyltrimethylammonium chloride chitosan (HACC) with a nonionic surfactant poloxamer in aqueous solution by monitoring the change of the oxidation peak current in cyclic voltammetry. Increasing values of the oxidation peak current were positively correlated with the antibacterial activity of HACC-poloxamer solutions. Optical microscope images, the zeta potential, and fluorescence spectroscopy showed that the aggregation state of HACC-poloxamer was related to the ratio of the two polymers and also to the antibacterial activity and oxidation peak current. At an HACC-to-poloxamer ratio of 1:0.75, the maximum surface charge density and the smooth edge of HACC-poloxamer aggregates can accelerate diffusion in aqueous solution. It is expected that this convenient method can be applied for a quick evaluation of the antibacterial activity of cationic biopolymers in aqueous solution. Graphical Abstract The cyclic voltammograms of MB in HACC/poloxamer solution, and the antibacterial efficiency against S. aureus after incubated with HACC (a) and 1/0.75 of HACC/poloxamer (b).

Radiosterilization of drugs in aqueous solutions may be achieved by the use of radioprotective excipients.

PubMed

Maquille, Aubert; Jiwan, Jean-Louis Habib; Tilquin, Bernard

2008-02-12

The aim of this study was to assess the feasibility of radiosterilization of drugs aqueous solutions and to evaluate the effects of some additives, such as mannitol, nicotinamide and pyridoxine, which might protect the drug from degradation. Metoclopramide was selected as a model drug. The structures of the degradation products were determined to gain insight on the radiolysis mechanisms in aqueous solution in order to design strategies to lower the drug degradation. Metoclopramide hydrochloride aqueous solutions with and without excipients were irradiated either with gamma rays or high-energy electrons. HPLC-DAD was used to measure the loss of chemical potency and to quantify the degradation products which were also characterized by LC-APCI-MS-MS. Metoclopramide recovery for gamma and electron beam-irradiated solutions containing either mannitol, pyridoxine or nicotinamide meets the pharmacopoeial specifications for metoclopramide content up to a 15 kGy irradiation so that metoclopramide solutions containing these excipients might be radiosterilized at 15 kGy either with gamma rays or high-energy electrons. Structures are proposed for the majority of radiolysis products. Similar radiolysis products were detected for gamma and electron beam irradiations but the chromatographic profiles were different (differences in the distribution of radiolysis products).

Aqueous pathways dominate permeation of solutes across Pisum sativum seed coats and mediate solute transport via diffusion and bulk flow of water.

PubMed

Niemann, Sylvia; Burghardt, Markus; Popp, Christian; Riederer, Markus

2013-05-01

The permeability of seed coats to solutes either of biological or anthropogenic origin plays a major role in germination, seedling growth and seed treatment by pesticides. An experimental set-up was designed for investigating the mechanisms of seed coat permeation, which allows steady-state experiments with isolated seed coats of Pisum sativum. Permeances were measured for a set of organic model compounds with different physicochemical properties and sizes. The results show that narrow aqueous pathways dominate the diffusion of solutes across pea seed coats, as indicated by a correlation of permeances with the molecular sizes of the compounds instead of their lipophilicity. Further indicators for an aqueous pathway are small size selectivity and a small effect of temperature on permeation. The application of an osmotic water potential gradient across isolated seed coats leads to an increase in solute transfer, indicating that the aqueous pathways form a water-filled continuum across the seed coat allowing the bulk flow of water. Thus, the uptake of organic solutes across pea testae has two components: (1) by diffusion and (2) by bulk water inflow, which, however, is relevant only during imbibition. © 2012 Blackwell Publishing Ltd.

Development of a Compact and Efficient Ice Thermal Energy Storage Vessel

NASA Astrophysics Data System (ADS)

Sasaguchi, Kengo; Ishikawa, Masatoshi; Muta, Kenji; Yoshino, Kiyotaka; Hayashi, Hiroko; Baba, Yoshiyuki

In the present study, the authors propose the use of a low concentration aqueous solution as phase change material for static-type ice-storage-vessels, instead of pure water commonly used today. If an aqueous solution with low concentration is used, even when a large amount of solution (aqueous ethylene glycol in this study) is solidified and bridging of ice developed around cold tubes occurs, the pressure increase could be prevented by the existence of a continuous liquid phase in the solid-liquid two-phase layer (mushy layer) which opens to an air gap at the top of a vessel. Therefore, one can continue to solidify an aqueous solution after bridging, achieving a high ice packing factor (IPF). First, experiments using small-scale test cells have been conducted to confirm the present idea, and then we have performed experiments using a large vessel with an early practical size. It was seen that a large pressure increase is prevented for the initial concentration of the solution C0 of 1.0%, and IPF obtained using the solution is much greater than 0.65 using pure water for which the solidification must be stopped before the bridging.

Aqueous Processing for Printed Organic Electronics: Conjugated Polymers with Multistage Cleavable Side Chains

PubMed Central

2017-01-01

The ability to process conjugated polymers via aqueous solution is highly advantageous for reducing the costs and environmental hazards of large scale roll-to-roll processing of organic electronics. However, maintaining competitive electronic properties while achieving aqueous solubility is difficult for several reasons: (1) Materials with polar functional groups that provide aqueous solubility can be difficult to purify and characterize, (2) many traditional coupling and polymerization reactions cannot be performed in aqueous solution, and (3) ionic groups, though useful for obtaining aqueous solubility, can lead to a loss of solid-state order, as well as a screening of any applied bias. As an alternative, we report a multistage cleavable side chain method that combines desirable aqueous processing attributes without sacrificing semiconducting capabilities. Through the attachment of cleavable side chains, conjugated polymers have for the first time been synthesized, characterized, and purified in organic solvents, converted to a water-soluble form for aqueous processing, and brought through a final treatment to cleave the polymer side chains and leave behind the desired electronic material as a solvent-resistant film. Specifically, we demonstrate an organic soluble polythiophene that is converted to an aqueous soluble polyelectrolyte via hydrolysis. After blade coating from an aqueous solution, UV irradiation is used to cleave the polymer’s side chains, resulting in a solvent-resistant, electroactive polymer thin film. In application, this process results in aqueous printed materials with utility for solid-state charge transport in organic field effect transistors (OFETs), along with red to colorless electrochromism in ionic media for color changing displays, demonstrating its potential as a universal method for aqueous printing in organic electronics. PMID:28979937

Aqueous Processing for Printed Organic Electronics: Conjugated Polymers with Multistage Cleavable Side Chains.

PubMed

Schmatz, Brian; Yuan, Zhibo; Lang, Augustus W; Hernandez, Jeff L; Reichmanis, Elsa; Reynolds, John R

2017-09-27

The ability to process conjugated polymers via aqueous solution is highly advantageous for reducing the costs and environmental hazards of large scale roll-to-roll processing of organic electronics. However, maintaining competitive electronic properties while achieving aqueous solubility is difficult for several reasons: (1) Materials with polar functional groups that provide aqueous solubility can be difficult to purify and characterize, (2) many traditional coupling and polymerization reactions cannot be performed in aqueous solution, and (3) ionic groups, though useful for obtaining aqueous solubility, can lead to a loss of solid-state order, as well as a screening of any applied bias. As an alternative, we report a multistage cleavable side chain method that combines desirable aqueous processing attributes without sacrificing semiconducting capabilities. Through the attachment of cleavable side chains, conjugated polymers have for the first time been synthesized, characterized, and purified in organic solvents, converted to a water-soluble form for aqueous processing, and brought through a final treatment to cleave the polymer side chains and leave behind the desired electronic material as a solvent-resistant film. Specifically, we demonstrate an organic soluble polythiophene that is converted to an aqueous soluble polyelectrolyte via hydrolysis. After blade coating from an aqueous solution, UV irradiation is used to cleave the polymer's side chains, resulting in a solvent-resistant, electroactive polymer thin film. In application, this process results in aqueous printed materials with utility for solid-state charge transport in organic field effect transistors (OFETs), along with red to colorless electrochromism in ionic media for color changing displays, demonstrating its potential as a universal method for aqueous printing in organic electronics.

Predicting the electronic properties of aqueous solutions from first-principles

NASA Astrophysics Data System (ADS)

Schwegler, Eric; Pham, Tuan Anh; Govoni, Marco; Seidel, Robert; Bradforth, Stephen; Galli, Giulia

Predicting the electronic properties of aqueous liquids has been a long-standing challenge for quantum-mechanical methods. Yet it is a crucial step in understanding and predicting the key role played by aqueous solutions and electrolytes in a wide variety of emerging energy and environmental technologies, including battery and photoelectrochemical cell design. Here we propose an efficient and accurate approach to predict the electronic properties of aqueous solutions, based on the combination of first-principles methods and experimental validation using state-of-the-art spectroscopic measurements. We present results for the photoelectron spectra of a broad range of solvated ions, showing that first-principles molecular dynamics simulations and electronic structure calculations using dielectric hybrid functionals provide a quantitative description of their electronic properties, including excitation energies, of the solvent and solutes. The proposed computational framework is general and applicable to other liquids, thereby offering great promise in understanding and engineering solutions and liquid electrolytes for a variety of important energy technologies. Part of this work was performed under the auspices of the U.S. Department of Energy at LLNL under Contract DE-AC52-07A27344.

Ultrasonic speed, densities and viscosities of xylitol in water and in aqueous tyrosine and phenylalanine solutions at different temperatures

NASA Astrophysics Data System (ADS)

Ali, A.; Bidhuri, P.; Uzair, S.

2014-07-01

Ultrasonic speed u, densities ρ and viscosities η of xylitol in water and in 0.001 m aqueous l-tyrosine (Tyr) and l-phenylalanine (Phe) have been measured at different temperatures. From the density and ultrasonic speed measurements apparent molar isentropic compression κ_{φ}, apparent molar isentropic compressions at infinite dilution κ_{{S,φ}}0 , experimental slope S K , hydration number n H , transfer partial molar isentropic compressibility Δ_{tr} κ_{{S,φ}}0 of xylitol from water to aqueous Tyr and Phe have been obtained. From the viscosity data, B-coefficient and B-coefficient of transfer Δ tr B of xylitol from water to aqueous Phe and Tyr at different temperatures have also been estimated. Gibbs free energies of activation of viscous flow per mole of solvent Δ μ 1 0# and per mole of solute Δ μ 2 0# have been calculated by using Feakins transition state theory for the studied systems. The calculated parameters have been interpreted in terms of solute-solute and solute-solvent interactions and hydration behavior of xylitol.

REMOVAL OF CESIUM FROM AQUEOUS SOLUTIONS BY ADSORPTION

DOEpatents

Knoll, K.C.

1963-07-16

A process of removing microquantities of cesium from aqueous solutions also containing macroquantities of other ions by adsorption on clinoptilolite is described. The invention resides in the pretreatment of the clinoptilolite by heating at 400 deg C and cooling prior to use. (AEC)

Highly efficient conductivity modulation of cinnamate-based light-responsive ionic liquids in aqueous solutions.

PubMed

Yang, Jie; Wang, Huiyong; Wang, Jianji; Zhang, Yue; Guo, Zhongjia

2014-12-11

A new class of cinnamate-based light-responsive ionic liquids was synthesized and characterized, and these ionic liquids with longer alkyl chains showed a remarkable increase in ionic conductivity under UV light irradiation in aqueous solutions.

EXTRACTION OF URANYL NITRATE FROM AQUEOUS SOLUTIONS

DOEpatents

Furman, N.H.; Mundy, R.J.

1957-12-10

An improvement in the process is described for extracting aqueous uranyl nitrate solutions with an organic solvent such as ether. It has been found that the organic phase will extract a larger quantity of uranyl nitrate if the aqueous phase contains in addition to the uranyl nitrate, a quantity of some other soluble nitrate to act as a salting out agent. Mentioned as suitable are the nitrates of lithium, calcium, zinc, bivalent copper, and trivalent iron.

Preliminary study on the photoproduction of hydroxyl radicals in aqueous solution with Aldrich humic acid, algae and Fe(III) under high-pressure mercury lamp irradiation.

PubMed

Liu, Xianli; Xu, Dong; Wu, Feng; Liao, Zhenhuan; Liu, Jiantong; Deng, Nansheng

2004-03-01

Under a high-pressure mercury lamp (HPML) and using an exposure time of 4 h, the photoproduction of hydroxyl radicals (*OH) could be induced in an aqueous solution containing humic acid (HA). Hydroxyl radicals were determined by high-performance liquid chromatography using benzene as a probe. The results showed that *OH photoproduction increased from 1.80 to 2.74 microM by increasing the HA concentration from 10 to 40 mg L(-1) at an exposure time of 4 h (pH 6.5). Hydroxyl radical photoproduction in aqueous solutions of HA containing algae was greater than that in the aqueous solutions of HA without algae. The photoproduction of *OH in the HA solution with Fe(III) was greater than that of the solution without Fe(III) at pH ranging from 4.0 to 8.0. The photoproduction of *OH in HA solution with algae with or without Fe(III) under a 250 W HPML was greater than that under a 125 W HPML. The photoproduction of *OH in irradiated samples was influenced by the pH. The results showed that HPML exposure for 4 h in the 4-8 pH range led to the highest *OH photoproduction at pH 4.0.

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

Popa, C. L.; Ciobanu, C. S.; Predoi, D., E-mail: dpredoi@gmail.com

The aim of this study was to synthetize new nanoparticles based on methyltrimethoxysilane coated hydroxyapatite (MTHAp) for lead removal in aqueous solutions. The morphological and compositional analysis of MTHAp was investigated by scanning electron microscopy (SEM) equipped with an energy dispersive X-ray spectrometer (EDS). Removal experiments of Pb{sup 2+} ions were carried out in aqueous solutions with controlled concentration of Pb{sup 2+} and at fixed pH of 5. After the removal experiment of Pb{sup 2+} ions from solutions, porous hydroxyapatite nanoparticles were transformed into PbMTHAp-5 via the adsorption of Pb{sup 2+} ions followed by a cation exchange reaction. Our resultsmore » demonstrate that the porous hydroxyapatite nanoparticles can be used as an adsorbent for removing Pb{sup 2+} ions from aqueous solution.« less

Thermochemical analysis of intermolecular interactions between N-acetylglycine and polyols in aqueous solutions

NASA Astrophysics Data System (ADS)

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

2017-05-01

The integral enthalpies of dissolution Δsol H m for N-acetylglycine in aqueous solutions of glycerol, ethylene glycol and 1,2-propylene glycol are measured via solution calorimetry. The standard enthalpies of dissolution (Δsol H 0) and transfer (Δtr H 0) for N-acetylglycine from water to aqueous solutions of polyhydric alcohols are calculated from experimental data. Positive values of enthalpy coefficients of pair interactions h xy for amino acids and polyol molecules are calculated using the McMillan-Mayer theory. The results are discussed using an approach for evaluating different types of interactions in ternary systems and the effect the structural features of interacting biomolecules have on the thermochemical characteristics of N-acetylglycine dissolution.

Osmotic potential calculations of inorganic and organic aqueous solutions over wide solute concentration levels and temperatures.

PubMed

Cochrane, T T; Cochrane, T A

2016-01-01

To demonstrate that the authors' new "aqueous solution vs pure water" equation to calculate osmotic potential may be used to calculate the osmotic potentials of inorganic and organic aqueous solutions over wide ranges of solute concentrations and temperatures. Currently, the osmotic potentials of solutions used for medical purposes are calculated from equations based on the thermodynamics of the gas laws which are only accurate at low temperature and solute concentration levels. Some solutions used in medicine may need their osmotic potentials calculated more accurately to take into account solute concentrations and temperatures. The authors experimented with their new equation for calculating the osmotic potentials of inorganic and organic aqueous solutions up to and beyond body temperatures by adjusting three of its factors; (a) the volume property of pure water, (b) the number of "free" water molecules per unit volume of solution, "Nf," and (c) the "t" factor expressing the cooperative structural relaxation time of pure water at given temperatures. Adequate information on the volume property of pure water at different temperatures is available in the literature. However, as little information on the relative densities of inorganic and organic solutions, respectively, at varying temperatures needed to calculate Nf was available, provisional equations were formulated to approximate values. Those values together with tentative t values for different temperatures chosen from values calculated by different workers were substituted into the authors' equation to demonstrate how osmotic potentials could be estimated over temperatures up to and beyond bodily temperatures. The provisional equations formulated to calculate Nf, the number of free water molecules per unit volume of inorganic and organic solute solutions, respectively, over wide concentration ranges compared well with the calculations of Nf using recorded relative density data at 20 °C. They were subsequently used to estimate Nf values at temperatures up to and excess of body temperatures. Those values, together with t values at temperatures up to and in excess of body temperatures recorded in the literature, were substituted in the authors' equation for the provisional calculation of osmotic potentials. The calculations indicated that solution temperatures and solute concentrations have a marked effect on osmotic potentials. Following work to measure the relative densities of aqueous solutions for the calculation of Nf values and the determination of definitive t values up to and beyond bodily temperatures, the authors' equation would enable the accurate estimations of the osmotic potentials of wide concentrations of aqueous solutions of inorganic and organic solutes over the temperature range. The study illustrates that not only solute concentrations but also temperatures have a marked effect on osmotic potentials, an observation of medical and biological significance.

The effect of nanoparticles and humic acid on technology critical element concentrations in aqueous solutions with soil and sand.

PubMed

Stepka, Zane; Dror, Ishai; Berkowitz, Brian

2018-01-01

As a consequence of their growing use in electronic and industrial products, increasing amounts of technology critical elements (TCEs) are being released to the environment. Currently little is known about the fate of many of these elements. Initial research on their potential environmental impact identifies TCEs as emerging contaminants. TCE movement in the environment is often governed by water systems. Research on "natural" waters so far demonstrates that TCEs tend to be associated with suspended particulate matter (SPM), which influences TCE aqueous concentrations (here: concentration of TCEs in dissolved form and attached to SPM) and transport. However, the relative potential of different types of SPM to interact with TCEs is unknown. Here we examine the potential of various types of particulate matter, namely different nanoparticles (NPs; Al 2 O 3, SiO 2 , CeO 2 , ZnO, montmorillonite, Ag, Au and carbon dots) and humic acid (HA), to impact TCE aqueous concentrations in aqueous solutions with soil and sand, and thus influence TCE transport in soil-water environments. We show that a combination of NPs and HA, and not NPs or HA individually, increases the aqueous concentrations of TCEs in soil solutions, for all tested NPs regardless of their type. TCEs retained on SPM, however, settle with time. In solutions with sand, HA alone is as influential as NPs+HA in keeping TCEs in the aqueous phase. Among NPs, Ag-NPs and Au-NPs demonstrate the highest potential for TCE transport. These results suggest that in natural soil-water environments, once TCEs are retained by soil, their partitioning to the aqueous phase by through-flowing water is unlikely. However, if TCEs are introduced to soil-water environments as part of solutions rich in NPs and HA, it is likely that NP and HA combinations can increase TCE stability in the aqueous phase and prevent their retention on soil and sand, thus facilitating TCE transport. Copyright © 2017 Elsevier B.V. All rights reserved.

Method of repressing the precipitation of calcium fluozirconate

DOEpatents

Newby, B.J.; Rhodes, D.W.

1973-12-25

Boric acid or a borate salt is added to aqueous solutions of fluoride containing radioactive wastes generated during the reprocessing of zirconium alloy nuclear fuels which are to be converted to solid form by calcining in a fluidized bed. The addition of calcium nitrate to the aqueous waste solutions to prevent fluoride volatility during calcination, causes the precipitation of calcium fluozirconate, which tends to form a gel at fluoride concentrations of 3.0 M or greater. The boron containing species introduced into the solution by the addition of the boric acid or borate salt retard the formation of the calcium fluozirconate precipitate and prevent formation of the gel. These boron containing species can be introduced into the solution by the addition of a borate salt but preferably are introduced by the addition of an aqueous solution of boric acid. (Official Gazette)

Monte Carlo track-structure calculations for aqueous solutions containing biomolecules

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

Turner, J.E.; Hamm, R.N.; Ritchie, R.H.

1993-10-01

Detailed Monte Carlo calculations provide a powerful tool for understanding mechanisms of radiation damage to biological molecules irradiated in aqueous solution. This paper describes the computer codes, OREC and RADLYS, which have been developed for this purpose over a number of years. Some results are given for calculations of the irradiation of pure water. comparisons are presented between computations for liquid water and water vapor. Detailed calculations of the chemical yields of several products from X-irradiated, oxygen-free glycylglycine solutions have been performed as a function of solute concentration. Excellent agreement is obtained between calculated and measured yields. The Monte Carlomore » analysis provides a complete mechanistic picture of pathways to observed radiolytic products. This approach, successful with glycylglycine, will be extended to study the irradiation of oligonucleotides in aqueous solution.« less

SEPARATION PROCESS FOR ZIRCONIUM AND COMPOUNDS THEREOF

DOEpatents

Crandall, H.W.; Thomas, J.R.

1959-06-30

The separation of zirconium from columbium, rare earths, yttrium and the alkaline earth metals, such mixtures of elements occurring in zirconium ores or neutron irradiated uranium is described. According to the invention a suitable separation of zirconium from a one normal acidic aqueous solution containing salts, nitrates for example, of tetravalent zirconium, pentavalent columbium, yttrium, rare earths in the trivalent state and alkaline earths can be obtained by contacting the aqueous solution with a fluorinated beta diketonc alone or in an organic solvent solution, such as benzene, to form a zirconium chelate compound. When the organic solvent is present the zirconium chelate compound is directly extracted; otherwise it is separated by filtration. The zirconium may be recovered from contacting the organic solvent solution containing the chelated compound by back extraction with either an aqueous hydrofluoric acid or an oxalic acid solution.

Binding selectivity of dibenzo-18-crown-6 for alkali metal cations in aqueous solution: A density functional theory study using a continuum solvation model.

PubMed

Choi, Chang Min; Heo, Jiyoung; Kim, Nam Joon

2012-08-08

Dibenzo-18-crown-6 (DB18C6) exhibits the binding selectivity for alkali metal cations in solution phase. In this study, we investigate the main forces that determine the binding selectivity of DB18C6 for the metal cations in aqueous solution using the density functional theory (DFT) and the conductor-like polarizable continuum model (CPCM). The bond dissociation free energies (BDFE) of DB18C6 complexes with alkali metal cations (M+-DB18C6, M = Li, Na, K, Rb, and Cs) in aqueous solution are calculated at the B3LYP/6-311++G(d,p)//B3LYP/6-31 + G(d) level using the CPCM. It is found that the theoretical BDFE is the largest for K+-DB18C6 and decreases as the size of the metal cation gets larger or smaller than that of K+, which agrees well with previous experimental results. The solvation energy of M+-DB18C6 in aqueous solution plays a key role in determining the binding selectivity of DB18C6. In particular, the non-electrostatic dispersion interaction between the solute and solvent, which depends strongly on the complex structure, is largely responsible for the different solvation energies of M+-DB18C6. This study shows that the implicit solvation model like the CPCM works reasonably well in predicting the binding selectivity of DB18C6 in aqueous solution.

Solubility of hydrogen sulfide in aqueous mixtures of monoethanolamine with N-methyldiethanolamine

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

Meng Hui Li; Keh Perng Shen

1993-01-01

Alkanolamine aqueous solutions are frequently used for the removal of acidic gases, such as CO[sub 2] and H[sub 2]S, from gas streams in the natural gas and synthetic ammonia industries and petroleum chemical plants. The solubilities of hydrogen sulfide in aqueous mixtures of monoethanolamine (MEA) with N-methyl-diethanolamine (MDEA) have been measured at 40, 60, 80, and 100C and at partial pressures of hydrogen sulfide ranging from 1.0 to 450 kPa. The mixtures of alkanolamines studied are 4.95 kmol/m[sup 3] MEA, 3.97 kmol/m[sup 3] MEA + 0.51 kmol/m[sup 3] MDEA, 2.0 kmol/m[sup 3] MEA + 1.54 kmol/m[sup 3] MDEA, and 2.57more » kmol/m[sup 3] MDEA aqueous solutions. The solubilities of hydrogen sulfide in aqueous alkanolamine solutions are reported as functions of the partial pressure of hydrogen sulfide at the temperatures of 40-100C.« less

Novel three-stage kinetic model for aqueous benzene adsorption on activated carbon.

PubMed

Choi, Jae-Woo; Choi, Nag-Choul; Lee, Soon-Jae; Kim, Dong-Ju

2007-10-15

We propose a novel kinetic model for adsorption of aqueous benzene onto both granular activated carbon (GAC) and powdered activated carbon (PAC). The model is based on mass conservation of benzene coupled with three-stage adsorption: (1) the first portion for an instantaneous stage or external surface adsorption, (2) the second portion for a gradual stage with rate-limiting intraparticle diffusion, and (3) the third portion for a constant stage in which the aqueous phase no longer interacts with activated carbon. An analytical solution of the kinetic model was validated with the kinetic data obtained from aqueous benzene adsorption onto GAC and PAC in batch experiments with two different solution concentrations (C(0)=300 mg L(-1), 600 mg L(-1)). Experimental results revealed that benzene adsorption for the two concentrations followed three distinct stages for PAC but two stages for GAC. The analytical solution could successfully describe the kinetic adsorption of aqueous benzene in the batch reaction system, showing a fast instantaneous adsorption followed by a slow rate-limiting adsorption and a final long constant adsorption. Use of the two-stage model gave incorrect values of adsorption coefficients in the analytical solution due to inability to describe the third stage.

Fractionation of poly(methacrylic acid) and poly(vinyl pyridine) in aqueous and organic mobile phases by multidetector thermal field-flow fractionation.

PubMed

Greyling, Guilaume; Pasch, Harald

2017-08-25

Multidetector thermal field-flow fractionation (ThFFF) is shown to be a versatile characterisation platform that can be used to characterise hydrophilic polymers in a variety of organic and aqueous solutions with various ionic strengths. It is demonstrated that ThFFF fractionates isotactic and syndiotactic poly(methacrylic acid) (PMAA) as well as poly(2-vinyl pyridine) (P2VP) and poly(4-vinyl pyridine) (P4VP) according to microstructure in organic solvents and that the ionic strength of the mobile phase has no influence on the retention behaviour of the polymers. With regard to aqueous solutions, it is shown that, despite the weak retention, isotactic and syndiotactic PMAA show different retention behaviours which can qualitatively be attributed to microstructure. Additionally, it is shown that the ionic strength of the mobile phase has a significant influence on the thermal diffusion of polyelectrolytes in aqueous solutions and that the addition of an electrolyte is essential to achieve a microstructure-based separation of P2VP and P4VP in aqueous solutions. Copyright © 2017 Elsevier B.V. All rights reserved.

Compositions comprising free-standing two-dimensional nanocrystals

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

Barsoum, Michel W.; Gogotsi, Yury; Abdelmalak, Michael Naguib

2017-12-05

The present invention is directed to methods of transferring urea from an aqueous solution comprising urea to a MXene composition, the method comprising contacting the aqueous solution comprising urea with the MXene composition for a time sufficient to form an intercalated MXene composition comprising urea.

RECOVERY OF METAL VALUES FROM AQUEOUS SOLUTIONS BY SOLVENT EXTRACTION

DOEpatents

Moore, R.L.

1959-09-01

An organic solvent mixure is described for extracting actinides from aqueous solutions; the solvent mixture consists of from 10 to 25% by volume of tributyl phosphate and the remainder a chlorine-fluorine-substituted saturated hydrocarbon having two carbon atoms in the molecule.

Method for making fine and ultrafine spherical particles of zirconium titanate and other mixed metal oxide systems

DOEpatents

Hu, Michael Z.

2006-05-23

Disclosed is a method for making amorphous spherical particles of zirconium titanate and crystalline spherical particles of zirconium titanate comprising the steps of mixing an aqueous solution of zirconium salt and an aqueous solution of titanium salt into a mixed solution having equal moles of zirconium and titanium and having a total salt concentration in the range from 0.01 M to about 0.5 M. A stearic dispersant and an organic solvent is added to the mixed salt solution, subjecting the zirconium salt and the titanium salt in the mixed solution to a coprecipitation reaction forming a solution containing amorphous spherical particles of zirconium titanate wherein the volume ratio of the organic solvent to aqueous part is in the range from 1 to 5. The solution of amorphous spherical particles is incubated in an oven at a temperature .ltoreq.100.degree. C. for a period of time .ltoreq.24 hours converting the amorphous particles to fine or ultrafine crystalline spherical particles of zirconium titanate.

Dissolution of lignin in green urea aqueous solution

NASA Astrophysics Data System (ADS)

Wang, Jingyu; Li, Ying; Qiu, Xueqing; Liu, Di; Yang, Dongjie; Liu, Weifeng; Qian, Yong

2017-12-01

The dissolution problem is the main obstacle for the value-added modification and depolymerization of industrial lignin. Here, a green urea aqueous solution for complete dissolution of various lignin is presented and the dissolution mechanism is analyzed by AFM, DLS and NMR. The results show that the molecular interaction of lignin decreases from 32.3 mN/m in pure water to 11.3 mN/m in urea aqueous solution. The immobility of 1H NMR spectra and the shift of 17O NMR spectra of urea in different lignin/urea solutions indicate that the oxygen of carbonyl in urea and the hydrogen of hydroxyl in lignin form new hydrogen bonds and break the original hydrogen bonds among lignin molecules. The shift of 1H NMR spectra of lignin and the decrease of interactions in model compound polystyrene indicate that urea also breaks the π-π interactions between aromatic rings of lignin. Lignin dissolved in urea aqueous has good antioxidant activity and it can scavenge at least 63% free radicals in 16 min.

Density Fluctuation in Aqueous Solutions and Molecular Origin of Salting-Out Effect for CO 2

DOE PAGES

Ho, Tuan Anh; Ilgen, Anastasia

2017-10-26

Using molecular dynamics simulation, we studied the density fluctuations and cavity formation probabilities in aqueous solutions and their effect on the hydration of CO 2. With increasing salt concentration, we report an increased probability of observing a larger than the average number of species in the probe volume. Our energetic analyses indicate that the van der Waals and electrostatic interactions between CO 2 and aqueous solutions become more favorable with increasing salt concentration, favoring the solubility of CO 2 (salting in). However, due to the decreasing number of cavities forming when salt concentration is increased, the solubility of CO 2more » decreases. The formation of cavities was found to be the primary control on the dissolution of gas, and is responsible for the observed CO 2 salting-out effect. Finally, our results provide the fundamental understanding of the density fluctuation in aqueous solutions and the molecular origin of the salting-out effect for real gas.« less

Viscosity, density, and surface tension of binary mixtures of water and N-methyldiethanolamine and water and diethanolamine and tertiary mixtures of these amines with water over the temperature range 20--100[degree]C

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

Rinker, E.B.; Oelschlager, D.W.; Colussi, A.T.

1994-04-01

Aqueous solutions of N-methyldiethanolamine (MDEA) and diethanolamine (DEA) are widely used in the industrial treatment of acid gas streams containing H[sub 2]S and CO[sub 2]. The density and viscosity of aqueous solutions of N-methyldiethanolamine were measured over the temperature range 60--100 C. The density and viscosity of aqueous solutions of diethanolamine and diethanolamine + N-methyldiethanolamine were measured over the temperature range 20--100 C. The surface tension of aqueous solutions of the above mixtures was measured over the temperature range 20--80 C. The concentration ranges were 10--50 mass % N-methyldiethanolamine, 10--30 mass % diethanolamine, and 50 mass % total amine concentrationmore » with mass ratios of 0.0441--0.5883 (diethanolamine to N-methyldiethanolamine). The measured quantities were found to be in agreement with the literature where data were available.« less

Removal of a hazardous heavy metal from aqueous solution using functionalized graphene and boron nitride nanosheets: Insights from simulations.

PubMed

Azamat, Jafar; Sattary, Batoul Shirforush; Khataee, Alireza; Joo, Sang Woo

2015-09-01

A computer simulation was performed to investigate the removal of Zn(2+) as a heavy metal from aqueous solution using the functionalized pore of a graphene nanosheet and boron nitride nanosheet (BNNS). The simulated systems were comprised of a graphene nanosheet or BNNS with a functionalized pore containing an aqueous ionic solution of zinc chloride. In order to remove heavy metal from an aqueous solution using the functionalized pore of a graphene nanosheet and BNNS, an external voltage was applied along the z-axis of the simulated box. For the selective removal of zinc ions, the pores of graphene and BNNS were functionalized by passivating each atom at the pore edge with appropriate atoms. For complete analysis systems, we calculated the potential of the mean force of ions, the radial distribution function of ion-water, the residence time of ions, the hydrogen bond, and the autocorrelation function of the hydrogen bond. Copyright © 2015 Elsevier Inc. All rights reserved.

Density Fluctuation in Aqueous Solutions and Molecular Origin of Salting-Out Effect for CO 2

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

Ho, Tuan Anh; Ilgen, Anastasia

Using molecular dynamics simulation, we studied the density fluctuations and cavity formation probabilities in aqueous solutions and their effect on the hydration of CO 2. With increasing salt concentration, we report an increased probability of observing a larger than the average number of species in the probe volume. Our energetic analyses indicate that the van der Waals and electrostatic interactions between CO 2 and aqueous solutions become more favorable with increasing salt concentration, favoring the solubility of CO 2 (salting in). However, due to the decreasing number of cavities forming when salt concentration is increased, the solubility of CO 2more » decreases. The formation of cavities was found to be the primary control on the dissolution of gas, and is responsible for the observed CO 2 salting-out effect. Finally, our results provide the fundamental understanding of the density fluctuation in aqueous solutions and the molecular origin of the salting-out effect for real gas.« less

The graphene oxide membrane immersing in the aqueous solution studied by electrochemical impedance spectroscopy

NASA Astrophysics Data System (ADS)

Zhang, Yongjing; Chen, Zhe; Yao, Lei; Wang, Xiao; Fu, Ping; Lin, Zhidong

2018-04-01

The interlayer spacing of graphene oxide (GO) is a key property for GO membrane. To probe the variation of interlayer spacing of the GO membrane immersing in KCl aqueous solution, electrochemical impedance spectroscopy (EIS), x-ray diffraction (XRD) and computational calculation was utilized in this study. The XRD patterns show that soaking in KCl aqueous solution leads to an increase of interlayer spacing of GO membrane. And the EIS results indicate that during the immersing process, the charge transfer resistance of GO membrane decreases first and then increases. Computational calculation confirms that intercalated water molecules can result in an increase of interlayer spacing of GO membrane, while the permeation of K+ ions would lead to a decrease of interlayer spacing. All the results are in agreement with each other. It suggests that during the immersing process, the interlayer spacing of GO enlarges first and then decreases. EIS can be a promisingly online method for examining the interlayer spacing of GO in the aqueous solution.

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

PubMed

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

2010-06-01

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

Reversible Condensation of DNA using a Redox-Active Surfactant

PubMed Central

Hays, Melissa E.; Jewell, Christopher M.; Lynn, David M.; Abbott, Nicholas L.

2008-01-01

We report characterization of aqueous solutions of dilute Lambda phage DNA containing the redox-active surfactant (11-ferrocenylundecyl)trimethylammonium bromide (FTMA) as a function of the oxidation state of the FTMA. FTMA undergoes a reversible one-electron oxidation from a reduced state that forms micelles in aqueous solution to an oxidized state (containing the ferrocenium cation) that does not selfassociate in solution. This investigation sought to test the hypothesis that FTMA can be used to achieve reversible control over the conformation of DNA-surfactant complexes in solution. Whereas DNA adopts extended coil conformations in aqueous solutions, our measurements revealed that addition of reduced FTMA (2–5μM) to aqueous solutions of DNA (5 μM in nucleotide units) resulted in coexistence of extended coils and compact globules in solution. At higher concentrations of reduced FTMA (up to 30μM), the DNA was present as compact globules only. In contrast, oxidized FTMA had no measurable effect on the conformation of DNA, allowing DNA to maintain an extended coil state up to a concentration of 75μM oxidized FTMA. We further demonstrate that it is possible to chemically or electrochemically transform the oxidation state of FTMA in preformed complexes of FTMA and DNA, thus achieving in situ control over the conformations of the DNA in solution. These results provide guidance for the design of surfactant systems that permit active control of DNA-surfactant interactions. PMID:17428073

Novel silver nanoparticle-enhanced fluorometric determination of trace tetracyclines in aqueous solutions.

PubMed

Wang, Ping; Wu, Tun-Hua; Zhang, Yong

2016-01-01

Metal-enhanced fluorescence (MEF) has exhibited promise for applications in fluorometric assays. The effects of silver nanoparticles (AgNP) on the fluorescence behaviours of tetracycline hydrochloride (TCH) and chlortetracycline hydrochloride (CTC) in aqueous solutions were investigated. The experimental results demonstrated that the fluorescence intensities of each tetracycline in water solutions were greatly enhanced by AgNP through the MEF effect. In addition, a novel silver nanoparticle-enhanced fluorometric method was established for the direct determination of TCH and CTC in aqueous solutions. Under optimum experimental conditions, the linear dynamic ranges for the determination of TCH and CTC in aqueous solutions varied from 0.10 to 6.0 mg L(-1) and 0.050 to 3.0 mg L(-1) with detection limits of 0.63 µg L(-1) and 0.19 µg L(-1), respectively, and with the relative standard deviation of less than 1.9% (n=9). The experimental recovery results for the determination of TCH and CTC in aqueous solutions ranged from 93-106% and 95-104%, respectively. Compared with the established method without the addition of AgNP, the limits of quantitation of the silver nanoparticle-enhanced fluorometric method were approximately 5-fold lower for TCH and 3-fold lower for CTC. Moreover, the newly established silver nanoparticle-enhanced fluorometric method was successfully applied to the direct determination of TCH and CTC in pharmaceutical preparations. Copyright © 2015 Elsevier B.V. All rights reserved.

The Unusual Colour of Copper Deposited on a Graphite Electrode in an Aqueous Solution of CuSO[subscript 4

ERIC Educational Resources Information Center

Petrusevski, Vladimir M.; Stojanovska, Marina

2010-01-01

The colour of the copper layer deposited on a graphite electrode during electrolysis of an aqueous solution of copper(II) sulfate looks whitish-grey when inspected in situ. Taking the electrode out of the solution reveals the familiar orange-red colour of deposited copper. The explanation is found in terms of the almost ideal complementary colours…

In-situ process for recovering hydrocarbons from a diatomite-type formation

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

Davis, B.W.

1984-12-04

An in-situ process for recovering hydrocarbons from a diatomite-type formation which comprises contacting the diatomite formation with a C/sub 4/-C/sub 10/ alcohol and thereafter displacing the hydrocarbon-alcohol mixture with an aqueous alkaline solution towards a production well. The aqueous alkaline solution can be displaced with additional solution or another suitable medium such as a connate water drive.

Thermal modulation voltammetry with laser heating at an aqueous|nitrobenzene solution microinterface: determination of the standard entropy changes of transfer for tetraalkylammonium ions.

PubMed

Hinoue, Teruo; Ikeda, Eiji; Watariguchi, Shigeru; Kibune, Yasuyuki

2007-01-01

Thermal modulation voltammetry (TMV) with laser heating was successfully performed at an aqueous|nitrobenzene (NB) solution microinterface, by taking advantage of the fact that laser light with a wavelength of 325.0 nm is optically transparent to the aqueous solution but opaque to the NB solution. When the laser beam impinges upon the interface from the aqueous solution side, a temperature is raised around the interface through the thermal diffusion subsequent to the light-to-heat conversion following the optical absorption by the NB solution near the interface. Based on such a principle, we achieved a fluctuating temperature perturbation around the interface for TMV by periodically irradiating the interface with the laser beam. On the other hand, the fluctuating temperature perturbation has influence on currents for transfer of an ion across the interface to produce fluctuating currents synchronized with the perturbation through temperature coefficients of several variables concerning the transfer, such as the standard transfer potential and the diffusion coefficient of the ion. Consequently, TMV has the possibility of providing information about the standard entropy change of transfer corresponding to a temperature coefficient of the standard transfer potential and a temperature coefficient of the diffusion coefficient. In this work, the aqueous|NB solution interface of 30 microm in diameter was irradiated with the laser beam at 10 Hz, and the currents synchronized with the periodical irradiation were recorded as a function of the potential difference across the interface in order to construct a TM voltammogram. TM voltammograms were measured for transfer of tetramethylammonium, tetraethylammonium, tetrapropylammonium, and tetra-n-butylammonium ions from the aqueous solution to the NB solution, and the standard entropy change of transfer was determined for each ion, according to an analytical procedure based on a mathematical expression of the TM voltammogram. Comparison of the values obtained in this work with the literature values has proved that TMV with laser heating is available for the determination of the standard entropy change of transfer for an ion.

Hot and cold water as a supercritical solvent

NASA Astrophysics Data System (ADS)

Fuentevilla, Daphne Anne

This dissertation addresses the anomalous properties of water at high temperatures near the vapor-liquid critical point and at low temperatures in the supercooled liquid region. The first part of the dissertation is concerned with the concentration dependence of the critical temperature, density, and pressure of an aqueous sodium chloride solution. Because of the practical importance of an accurate knowledge of critical parameters for industrial, geochemical, and biological applications, an empirical equation for the critical locus of aqueous sodium chloride solutions was adopted in 1999 by the International Association for the Properties of Water and Steam (IAPWS) as a guideline. However, since this original Guideline on the Critical Locus of Aqueous Solutions of Sodium Chloride was developed, two new theoretical developments occurred, motivating the first part of this dissertation. Here, I present a theory-based formulation for the critical parameters of aqueous sodium chloride solutions as a proposed replacement for the empirical formulation currently in use. This formulation has been published in the International Journal of Thermophysics and recommended by the Executive Committee of IAPWS for adoption as a Revised Guideline on the Critical Locus of Aqueous Solutions of Sodium Chloride. The second part of the dissertation addresses a new concept, considering cold water as a supercritical solvent. Based on the idea of a second, liquid-liquid, critical point in supercooled water, we explore the possibility of supercooled water as a novel supercooled solvent through the thermodynamics of critical phenomena. In 2006, I published a Physical Review letter presenting a parametric scaled equation of state for supercooled-water. Further developments based on this work led to a phenomenological mean-field "two-state" model, clarifying the nature of the phase separation in a polyamorphic single-component liquid. In this dissertation, I modify this two-state model to incorporate solutes. Critical lines emanating from the pure-water critical point show how even small additions of solute may significantly affect the thermodynamic properties and phase behavior of supercooled aqueous solutions. Some solutes, such as glycerol, can prevent spontaneous crystallization, thus making liquid-liquid separation in supercooled water experimentally accessible. This work will help in resolving the question on liquid polyamorphism in supercooled water.

Solvent and process for recovery of hydroxide from aqueous mixtures

DOEpatents

Moyer, Bruce A.; Chambliss, C. Kevin; Bonnesen, Peter V.; Keever, Tamara J.

2001-01-01

Hydroxide values and associated alkali metal may be recovered from alkaline aqueous solutions using classes of fluorinated alcohols in a water immiscible solvent. The alcohols are characterized by fluorine substituents which are proximal to the acidic alcohol protons and are located to adjust the acidity of the extractant and the solubility of the extractant in the solvent. A method for stripping the extractant and solvent to regenerate the extractant and purified aqueous hydroxide solution is described.

Acid-base properties of 2-phenethyldithiocarbamoylacetic acid, an antitumor agent

NASA Astrophysics Data System (ADS)

Novozhilova, N. E.; Kutina, N. N.; Petukhova, O. A.; Kharitonov, Yu. Ya.

2013-07-01

The acid-base properties of the 2-phenethyldithiocarbamoylacetic acid (PET) substance belonging to the class of isothiocyanates and capable of inhibiting the development of tumors on many experimental models were studied. The acidity and hydrolysis constants of the PET substance in ethanol, acetone, aqueous ethanol, and aqueous acetone solutions were determined from the data of potentiometric (pH-metric) titration of ethanol and acetone solutions of PET with aqueous solidum hydroxide at room temperature.

Complexation Enhancement Drives Water-to-Oil Ion Transport: A Simulation Study

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

Qiao, Baofu; Ferru, Geoffroy; Ellis, Ross J.

We address the structures and energetics of ion solvation in aqueous and organic solutions to understand liquid-liquid ion transport. Atomistic molecular dynamics (MD) simulations with polarizable force field are performed to study the coordination transformations driving lanthanide (Ln(III)) and nitrate ion transport between aqueous and an alkylamide-oil solution. An enhancement of the coordination behavior in the organic phase is achieved in contrast with the aqueous solution. In particular, the coordination number of Ce3+ increases from 8.9 in the aqueous to 9.9 in the organic solutions (from 8 in the aqueous to 8.8 in the organic systems for Yb3+). Moreover, themore » local coordination environ ment changes dramatically. Potential of mean force calculations show that the Ln(III)-ligand coordination interaction strengths follow the order of Ln(III-)nitrate> Ln(III)-water>Ln(III)-DMDBTDMA. They increase 2-fold in the lipophilic environment in comparison to the aqueous phase, and we attribute this to the shedding of the outer solvation shell. Our findings highlight the importance of outer sphere interactions on the competitive solvation energetics that cause ions to migrate between immiscible phases; an essential ingredient for advancing important applications such as rare earth metal separations. Some open questions in simulating the coordination behavior of heavy metals are also addressed.« less

Removal of Cr(VI) from Aqueous Environments Using Micelle-Clay Adsorption

PubMed Central

Qurie, Mohannad; Khamis, Mustafa; Manassra, Adnan; Ayyad, Ibrahim; Nir, Shlomo; Scrano, Laura; Bufo, Sabino A.; Karaman, Rafik

2013-01-01

Removal of Cr(VI) from aqueous solutions under different conditions was investigated using either clay (montmorillonite) or micelle-clay complex, the last obtained by adsorbing critical micelle concentration of octadecyltrimethylammonium ions onto montmorillonite. Batch experiments showed the effects of contact time, adsorbent dosage, and pH on the removal efficiency of Cr(VI) from aqueous solutions. Langmuir adsorption isotherm fitted the experimental data giving significant results. Filtration experiments using columns filled with micelle-clay complex mixed with sand were performed to assess Cr(VI) removal efficiency under continuous flow at different pH values. The micelle-clay complex used in this study was capable of removing Cr(VI) from aqueous solutions without any prior acidification of the sample. Results demonstrated that the removal effectiveness reached nearly 100% when using optimal conditions for both batch and continuous flow techniques. PMID:24222757

Method for removing organic liquids from aqueous solutions and mixtures

DOEpatents

Hrubesh, Lawrence W.; Coronado, Paul R.; Dow, Jerome P.

2004-03-23

A method for removing organic liquids from aqueous solutions and mixtures. The method employs any porous material preferably in granular form and having small pores and a large specific surface area, that is hydrophobic so that liquid water does not readily wet its surface. In this method, organics, especially organic solvents that mix with and are more volatile than water, are separated from aqueous solution by preferentially evaporating across the liquid/solid boundary formed at the surfaces of the hydrophobic porous materials. Also, organic solvents that are immiscible with water, preferentially wet the surfaces of the hydrophobic material and are drawn within the porous materials by capillary action.

Label-free monitoring of interaction between DNA and oxaliplatin in aqueous solution by terahertz spectroscopy

NASA Astrophysics Data System (ADS)

Wu, Xiaojun; E, Yiwen; Xu, Xinlong; Wang, Li

2012-07-01

We demonstrated the feasibility of applying terahertz time-domain spectroscopy (THz-TDS) to monitor the molecular reactions in aqueous solutions of anticancer drug oxaliplatin with λ-DNA and macrophages DNA. The reaction time dependent refractive index and absorption coefficient were extracted and analyzed. The reaction half-decaying time of about 4.0 h for λ-DNA and 12.9 h for M-DNA was established. The results suggest that the THz-TDS detection could be an effective label-free technique to sense the molecular reaction in aqueous solutions and could be very useful in biology, medicine, and pharmacy industry.

Viscosity of aqueous solutions of n-methyldiethanolamine and of diethanolamine

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

Teng, T.T.; Maham, Y.; Hepler, L.G.

1994-04-01

Aqueous solutions of alkanolamines such as monoethanolamine (MEA), diethanolamine (DEA), N-methyldiethanolamine (MDEA), di-2-propanolamine (DIPA), and bis[2-(hydroxyamino)ethyl] ether (DGA) are good solvents for the removal of acid gases such as CO[sub 2] and H[sub 2]S from the gas streams of many processes in the natural gas, petroleum, ammonia synthesis, and some chemical industries. The viscosity of aqueous solutions of methyldiethanolamine (MDEA) and of diethanolamine (DEA) have been measured at five temperatures in the range 25--80 C throughout the whole concentration range. The viscosity has been correlated as a function of composition for use in industrial calculations.

Ab initio molecular dynamics simulation of aqueous solution of nitric oxide in different formal oxidation states

NASA Astrophysics Data System (ADS)

Venâncio, Mateus F.; Rocha, Willian R.

2015-10-01

Ab initio molecular dynamics simulations were used to investigate the early chemical events involved in the dynamics of nitric oxide (NOrad), nitrosonium cation (NO+) and nitroxide anion (NO-) in aqueous solution. The NO+ ion is very reactive in aqueous solution having a lifetime of ∼4 × 10-13 s, which is shorter than the value of 3 × 10-10 s predicted experimentally. The NO+ reacts generating the nitrous acid as an intermediate and the NO2- ion as the final product. The dynamics of NOrad revealed the reversibly formation of a transient anion radical species HONOrad -.

New findings on the influence of carbon surface curvature on energetics of benzene adsorption from aqueous solutions

NASA Astrophysics Data System (ADS)

Wiśniewski, Marek; Werengowska-Ciećwierz, Karolina; Terzyk, Artur P.

2015-01-01

Immersional measurements of benzene adsorption form dilute aqueous solutions are reported for the first time together with the measurements of the enthalpy of benzene adsorption. Benzene adsorption from aqueous solution is an exothermic process. Our results show that with the decrease in carbon nanotube diameter the process becomes more exothermic, and the enthalpy of benzene adsorption correlates with the BET surface area and the electrostatic field strength of the tubes. Possible explanations of the results are proposed, and the most probable is that the change in carbon hybridisation with curvature leads to creation of stronger energetically adsorption sites than observed for graphite.

A process for the preparation of cysteine from cystine

DOEpatents

Chang, Shih-Ger; Liu, David K.; Griffiths, Elizabeth A.; Littlejohn, David

1989-01-01

The present invention in one aspect relates to a process for the simultaneous removal of NO.sub.x and SO.sub.2 from a fluid stream comprising mixtures thereof and in another aspect relates to the separation, use and/or regeneration of various chemicals contaminated or spent in the process and which includes the steps of: (A) contacting the fluid stream at a temperature of between about 105.degree. and 180.degree. C. with a liquid aqueous slurry or solution comprising an effective amount of an iron chelate of an amino acid moiety having at least one --SH group; (B) separating the fluid stream from the particulates formed in step (A) comprising the chelate of the amino acid moiety and fly ash; (C) washing and separating the particulates of step (B) with an aqeous solution having a pH value of between about 5 to 8; (D) subsequently washing and separating the particulates of step (C) with a strongly acidic aqueous solution having a pH value of between about 1 to 3; (E) washing and separating the particulates of step (D) with an basic aqueous solution having a pH value of between about 9 to 12; (F) optionally adding additional amino acid moiety, iron (II) and alkali to the aqueous liquid from step (D) to produce an aqueous solution or slurry similar to that in step (A) having a pH value of between about 4 to 12; and (G) recycling the aqueous slurry of step (F) to the contacting zone of step (A). Steps (D) and (E) can be carried out in the reverse sequence, however the preferred order is (D) and then (E). In a preferred embodiment the present invention provides an improved process for the preparation (regeneration) of cysteine from cystine, which includes reacting an aqueous solution of cystine at a pH of between about 9 to 13 with a reducing agent selected from hydrogen sulfide or alkali metal sulfides, sulfur dioxide, an alkali metal sulfite or mixtures thereof for a time and at a temperature effective to cleave and reduce the cystine to cysteine with subsequent recovery of the cysteine. In another preferred embodiment the present invention provides a process for the removal of NO.sub.x, SO.sub.2 and particulates from a fluid stream which includes the steps of (A) injecting into a reaction zone an aqueous solution itself comprising (i) an amino acid moiety selected from those described above; (ii) iron (II) ion; and (iii) an alkali, wherein the aqueous solution has a pH of between about 4 and 11; followed by solids separation and washing as is described in steps (B), (C), (D) and (E) above. The overall process is useful to reduce acid rain components from combustion gas sources.

RECOVERY OF URANIUM FROM AQUEOUS PHOSPHATE-CONTAINING SOLUTIONS

DOEpatents

Igelsrud, I.; Stephen, E.F.

1959-08-11

ABS>A method is presented for recovering hexavalent uranium from an acidic phosphaie solution. A high molecular weight amine, such as a mixture of cccoanut oil amines, is added to the solution in such amount as to give a ratio of about 2000 parts by weight of amine to 1 part by weight of uranium. The uranium is precipitated with the amines and the whole filtered from the solution. The uranium is leached from the amine mass by washing with aqueous sodium carbonate solution; and the amine mixture is available for reuse.

Ca(2+) -complex stability of GAPAGPLIVPY peptide in gas and aqueous phase, investigated by affinity capillary electrophoresis and molecular dynamics simulations and compared to mass spectrometric results.

PubMed

Nachbar, Markus; El Deeb, Sami; Mozafari, Mona; Alhazmi, Hassan A; Preu, Lutz; Redweik, Sabine; Lehmann, Wolf Dieter; Wätzig, Hermann

2016-03-01

Strong, sequence-specific gas-phase bindings between proline-rich peptides and alkaline earth metal ions in nanoESI-MS experiments were reported by Lehmann et al. (Rapid Commun. Mass Spectrom. 2006, 20, 2404-2410), however its relevance for physiological-like aqueous phase is uncertain. Therefore, the complexes should also be studied in aqueous solution and the relevance of the MS method for binding studies be evaluated. A mobility shift ACE method was used for determining the binding between the small peptide GAPAGPLIVPY and various metal ions in aqueous solution. The findings were compared to the MS results and further explained using computational methods. While the MS data showed a strong alkaline earth ion binding, the ACE results showed nonsignificant binding. The proposed vacuum state complex also decomposed during a molecular dynamic simulation in aqueous solution. This study shows that the formed stable peptide-metal ion adducts in the gas phase by ESI-MS does not imply the existence of analogous adducts in the aqueous phase. Comparing peptide-metal ion interaction under the gaseous MS and aqueous ACE conditions showed huge difference in binding behavior. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

EQ3NR, a computer program for geochemical aqueous speciation-solubility calculations: Theoretical manual, user`s guide, and related documentation (Version 7.0); Part 3

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

Wolery, T.J.

1992-09-14

EQ3NR is an aqueous solution speciation-solubility modeling code. It is part of the EQ3/6 software package for geochemical modeling. It computes the thermodynamic state of an aqueous solution by determining the distribution of chemical species, including simple ions, ion pairs, and complexes, using standard state thermodynamic data and various equations which describe the thermodynamic activity coefficients of these species. The input to the code describes the aqueous solution in terms of analytical data, including total (analytical) concentrations of dissolved components and such other parameters as the pH, pHCl, Eh, pe, and oxygen fugacity. The input may also include a desiredmore » electrical balancing adjustment and various constraints which impose equilibrium with special pure minerals, solid solution end-member components (of specified mole fractions), and gases (of specified fugacities). The code evaluates the degree of disequilibrium in terms of the saturation index (SI = 1og Q/K) and the thermodynamic affinity (A = {minus}2.303 RT log Q/K) for various reactions, such as mineral dissolution or oxidation-reduction in the aqueous solution itself. Individual values of Eh, pe, oxygen fugacity, and Ah (redox affinity) are computed for aqueous redox couples. Equilibrium fugacities are computed for gas species. The code is highly flexible in dealing with various parameters as either model inputs or outputs. The user can specify modification or substitution of equilibrium constants at run time by using options on the input file.« less

Biosorption of copper ions from aqueous solution using rape straw powders: Optimization, equilibrium and kinetic studies.

PubMed

Liu, Xin; Chen, Zhao-Qiong; Han, Bin; Su, Chun-Li; Han, Qin; Chen, Wei-Zhong

2018-04-15

In this paper, the adsorption behaviors of Cu(II) from the aqueous solution using rape straw powders were studied. The effects of initial Cu(II) concentration, pH range and absorbent dosage on the adsorption efficiency of Cu(II) by rape straw powder were investigated by Box-Behnken Design based on response surface methodology. The values of coefficient constant of the nonlinear models were 0.9997, 0.9984 and 0.9944 for removal Cu(II) from aqueous solution using rape straw shell, seed pods and straw pith core, respectively, which could navigate the design space for various factors on effects of biosorption Cu(II) from aqueous solution. The various factors of pH and biosorbents dosage were the key factors that affecting the removal efficiency of Cu(II) from aqueous solution. The biosorption equilibrium data presented its favorable monolayer adsorption Cu(II) onto shell, seed pods and straw pith core, respectively. The pseudo-second order kinetic model was the proper approach to determine the adsorption kinetics. The biosorption of Cu(II) onto surfaces of rape straw powders were confirmed and ion-exchanged in the adsorption process by energy dispersive spectrometer. The critical groups, -OH, -CH, -NH 3 + , -CH 3 , -NH and -C-O, exhibited by the infrared spectra results, changed to suggest that these groups played critical roles, especially -CH 3 in the adsorption of copper ions onto rape straw powders. The study provided evidences that rape straw powders can be used for removing Cu(II) from aqueous water. Copyright © 2017 Elsevier Inc. All rights reserved.

PROPERTY CHANGES IN AQUEOUS SOLUTIONS DUE TO SURFACTANT TREATMENT OF PCE: IMPLICATIONS TO GEOPHYSICAL MEASUREMENTS

EPA Science Inventory

Select physicochemical properties of aqueous solutions composed of surfactants, dye, and

perchloroethylene (PCE) were evaluated through a response surface quadratic design

model of experiment. Nine surfactants, which are conventionally used in the

remediation...

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

Code of Federal Regulations, 2013 CFR

2013-10-01

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

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

Code of Federal Regulations, 2011 CFR

2011-10-01

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

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

Code of Federal Regulations, 2010 CFR

2010-10-01

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

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

Code of Federal Regulations, 2012 CFR

2012-10-01

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

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

Code of Federal Regulations, 2014 CFR

2014-10-01

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

PRODUCTION OF THORIUM FLUORIDE

DOEpatents

Zachariasen, W.H.

1959-08-11

A process is presented for producing anhydrous thorium fluoride comprising the step of contacting a saturated aqueous solution of thorium nitrate with an aqueous solution of hydrofluoric acid having a concentration of about 45 to 50% by weight at a temperature above 70 deg C whereby anhydrous thorium fluoride precipitates.

Surface Charge and Hydrophobicity of Endospores of Bacillus anthracis and Related Species in Aqueous Solution

EPA Science Inventory

The surface properties of microorganisms play an important role in attachment and detachment in the environment. The change in surface charge can effect coagulation, disinfection, adhesion to surfaces, uptake of chemicals, and environmental transport. In aqueous solution, cell s...

Extractive recovery of phenol and p-alkylphenols from aqueous solutions with hydrophobic ketones

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

Korenman, Ya.I.; Ermolaeva, T.N.; Podolina, E.A.

1994-03-10

Aliphatic and cyclic hydrophobic ketones were used for extractive recovery of phenol and p-alkylphenols from aqueous solutions, giving a 95-98% extraction of toxicants under the recommended conditions. The extracting agents were cyclohexanone, methylcyclohexanone, butyl methyl ketone, and isobutyl methyl ketone.

Sorption of Ochratoxin A from aqueous solutions using beta-cyclodextrin-polyurethane polymer

USDA-ARS?s Scientific Manuscript database

The ability of a cyclodextrin-polyurethane polymer to remove ochratoxin A from aqueous solutions, including wine, was examined by batch rebinding assays and equilibrium sorption isotherms. The results were fit to two parameter models. Freundlich analysis of the sorption isotherm indicates the polyme...

The structure and stability of aqueous rare-earth elements in hydrothermal fluids: New results on neodymium(III) aqua and chloroaqua complexes in aqueous solutions to 500 °C and 520 MPa

USGS Publications Warehouse

Mayanovic, Robert A.; Anderson, Alan J.; Bassett, William A.; Chou, I.-Ming

2009-01-01

X-ray absorption spectroscopy (XAS) measurements were made at the Nd L3-edge on neodymium(III) aqua and chloroaqua complexes in low pH aqueous solutions from 25 to 500????C and up to 520??MPa. Analysis of the extended X-ray absorption fine structure of the XAS spectra measured from a 0.07??m Nd/0.16??m HNO3 aqueous solution reveals a contraction of the Nd-O distance of the Nd3+ aqua ion at a uniform rate of ~ 0.013????/100????C and a uniform reduction of the number of coordinated H2O molecules from 10.0 ?? 0.9 to 7.4 ?? 0.9 over the range from 25 to 500????C and up to 370??MPa. The rate of reduction of the first-shell water molecules with temperature for Nd3+ (26%) is intermediate between the rate for the Gd3+ aqua ion (22% from 25 to 500????C) and the rates for the Eu3+ (29% from 25 to 400????C) and the Yb3+ aqua ions (42% from 25 to 500????C) indicating an intermediate stability of the Nd3+ aqua ion consistent with the tetrad effect. Nd L3-edge XAS measurements of 0.05??m NdCl3 aqueous solution at 25 to 500????C and up to 520??MPa show that stepwise inner-sphere complexes most likely of the type Nd(H2O)?? - nCln+3 - n occur in the solution at elevated temperatures, where ?? ??? 9 at 150????C decreasing to ~ 6 at 500????C and the number of chloride ions (n) of the chloroaqua complexes increases uniformly with temperature from 1.2 ?? 0.2 to 2.0 ?? 0.2 in the solution upon increase of temperature from 150 to 500????C. Conversely, the number of H2O ligands of Nd(H2O)?? - nCln+3 - n complexes is uniformly reduced with temperature from 7.5 ?? 0.8 to 3.7 ?? 0.3 in the aqueous solution, in the same temperature range. These data show greater stability of neodymium(III) than gadolinium(III) and ytterbium(III) chloride complexes in low pH aqueous solutions at elevated temperatures. Our data suggest a greater stability of aqueous light REE than that of heavy REE chloride complexes in low pH fluids at elevated temperatures consistent with REE analysis of fluids from deep-sea hydrothermal vents. ?? 2008 Elsevier B.V.

Effect of solute nature on the polyamorphic transition in glassy polyol aqueous solutions.

PubMed

Suzuki, Yoshiharu

2017-08-14

I examined the polyamorphic behavior of glassy dilute aqueous solutions of polyols (ethylene glycol, glycerol, meso-erythritol, xylitol, and D-sorbitol) under pressure at low temperatures. Although the volume change of the glassy aqueous solution varied continuously against pressure, the rate of the volume change appeared to vary discontinuously at the onset pressure of the gradual polyamorphic transition. It is thought that low-density liquid-like solvent water and high-density liquid-like solvent water coexist during the transition. Moreover, the existence of a solute induces the shift of polyamorphic transition to the lower-pressure side. The effect of a solute on the polyamorphic transition becomes larger in the order ethylene glycol, glycerol, meso-erythritol, xylitol, and D-sorbitol. Therefore, the solute can become a variable controlling the polyamorphic state of liquid water. This experimental result suggests that the metastable-equilibrium phase boundary between the low-density and the high-density amorphs for pure water is likely to be located at 0.22-0.23 GPa at about 150 K, which is slightly larger than the previously estimated pressure. Moreover, the solute-nature dependence on the polyamorphic transition seems to connect to that on the homogeneous nucleation temperature of polyol aqueous solution at ambient pressure. The region in which a low-density liquid appears coincides with the region in which the nucleus of ice Ih appears, suggesting that the formation of a low-density liquid is a precursory phenomenon of the nucleation of ice Ih.

Effect of solute nature on the polyamorphic transition in glassy polyol aqueous solutions

NASA Astrophysics Data System (ADS)

Suzuki, Yoshiharu

2017-08-01

I examined the polyamorphic behavior of glassy dilute aqueous solutions of polyols (ethylene glycol, glycerol, meso-erythritol, xylitol, and D-sorbitol) under pressure at low temperatures. Although the volume change of the glassy aqueous solution varied continuously against pressure, the rate of the volume change appeared to vary discontinuously at the onset pressure of the gradual polyamorphic transition. It is thought that low-density liquid-like solvent water and high-density liquid-like solvent water coexist during the transition. Moreover, the existence of a solute induces the shift of polyamorphic transition to the lower-pressure side. The effect of a solute on the polyamorphic transition becomes larger in the order ethylene glycol, glycerol, meso-erythritol, xylitol, and D-sorbitol. Therefore, the solute can become a variable controlling the polyamorphic state of liquid water. This experimental result suggests that the metastable-equilibrium phase boundary between the low-density and the high-density amorphs for pure water is likely to be located at 0.22-0.23 GPa at about 150 K, which is slightly larger than the previously estimated pressure. Moreover, the solute-nature dependence on the polyamorphic transition seems to connect to that on the homogeneous nucleation temperature of polyol aqueous solution at ambient pressure. The region in which a low-density liquid appears coincides with the region in which the nucleus of ice Ih appears, suggesting that the formation of a low-density liquid is a precursory phenomenon of the nucleation of ice Ih.

Identification of Rare Lewis Oligosaccharide Conformers in Aqueous Solution Using Enhanced Sampling Molecular Dynamics.

PubMed

Alibay, Irfan; Burusco, Kepa K; Bruce, Neil J; Bryce, Richard A

2018-03-08

Determining the conformations accessible to carbohydrate ligands in aqueous solution is important for understanding their biological action. In this work, we evaluate the conformational free-energy surfaces of Lewis oligosaccharides in explicit aqueous solvent using a multidimensional variant of the swarm-enhanced sampling molecular dynamics (msesMD) method; we compare with multi-microsecond unbiased MD simulations, umbrella sampling, and accelerated MD approaches. For the sialyl Lewis A tetrasaccharide, msesMD simulations in aqueous solution predict conformer landscapes in general agreement with the other biased methods and with triplicate unbiased 10 μs trajectories; these simulations find a predominance of closed conformer and a range of low-occupancy open forms. The msesMD simulations also suggest closed-to-open transitions in the tetrasaccharide are facilitated by changes in ring puckering of its GlcNAc residue away from the 4 C 1 form, in line with previous work. For sialyl Lewis X tetrasaccharide, msesMD simulations predict a minor population of an open form in solution corresponding to a rare lectin-bound pose observed crystallographically. Overall, from comparison with biased MD calculations, we find that triplicate 10 μs unbiased MD simulations may not be enough to fully sample glycan conformations in aqueous solution. However, the computational efficiency and intuitive approach of the msesMD method suggest potential for its application in glycomics as a tool for analysis of oligosaccharide conformation.

21 CFR 522.144 - Arsenamide sodium aqueous injection.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Arsenamide sodium aqueous injection. 522.144... § 522.144 Arsenamide sodium aqueous injection. (a) Chemical name. [[(p-Carbamoylphenyl) arsylene]dithio diacetic acid, sodium salt. (b) Specifications. The drug is a sterile aqueous solution and each milliliter...

21 CFR 522.144 - Arsenamide sodium aqueous injection.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Arsenamide sodium aqueous injection. 522.144... § 522.144 Arsenamide sodium aqueous injection. (a) Chemical name. [[(p-Carbamoylphenyl) arsylene]dithio diacetic acid, sodium salt. (b) Specifications. The drug is a sterile aqueous solution and each milliliter...

Li2MoO4 crystal growth from solution activated by low-frequency vibrations

NASA Astrophysics Data System (ADS)

Barinova, Olga; Sadovskiy, Andrey; Ermochenkov, Ivan; Kirsanova, Svetlana; Sukhanova, Ekaterina; Kostikov, Vladimir; Belov, Stanislav; Mozhevitina, Elena; Khomyakov, Andrew; Kuchuk, Zhanna; Zharikov, Eugeny; Avetissov, Igor

2017-01-01

The possibility of Li2MoO4 crystal growth from aqueous solutions activated by axial vibrational control (AVC) technique was investigated. It was found out that a low-frequency mechanical activation of the solution led to an increase of Li2MoO4 equilibrium solubility in aqueous solution for 11 rel% in the 25-29 °C temperature range. The changes in solution structure were analyzed in situ by Raman study of the solution. The AVC activation of solution resulted in a re-faceting of growing crystals, a smoothing of a face surface morphology and reduction of water content in the crystal.

CESIUM RECOVERY FROM AQUEOUS SOLUTIONS

DOEpatents

Schneider, R.A.

1961-06-20

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

Synthesis of Energetic Materials by Rapid Expansion of a Supercritical Solution into Aqueous Solution (RESS-AS) Process

DTIC Science & Technology

2010-12-02

1366-1373, (2005). 16. Young, T . J ., Mawson , S., Johnston, K. P., Henriksen, I. B., Pace, G. W., and Mishra, A. K., Rapid Expansion from...Synthesis of Energetic Materials by Rapid Expansion of a Supercritical Solution into Aqueous Solution (RESS-AS) Process* J . T . Essel, A. C...Cortopassi, K. K. Kuo, J . H. Adair, and C. G. Leh The Pennsylvania State University University Park, PA 16802 USA T . M. Klapötke Ludwig Maximilian

Aqueous route to facile, efficient and functional silica coating of metal nanoparticles at room temperature

NASA Astrophysics Data System (ADS)

Shah, Kwok Wei; Sreethawong, Thammanoon; Liu, Shu-Hua; Zhang, Shuang-Yuan; Tan, Li Sirh; Han, Ming-Yong

2014-09-01

Various metal (Ag, Au, and Pt)@thiol-functionalized silica (SiO2-SH) nanoparticles (NPs) are successfully prepared at room temperature by a facile, efficient, functional, universal and scalable coating process in alcohol-free aqueous solution using pre-hydrolyzed 3-(mercaptopropyl)trimethoxysilane (MPTMS). The controlled pre-hydrolysis of the silane precursor in water and the consecutive condensation processes are the key to achieve the effective and uniform silica coating on metal NPs in aqueous solution. The thickness of the silica shell is tuned by simply varying the coating time. The silica shell can act as an effective protecting layer for Ag NPs in Ag@SiO2-SH NPs under conditions for silica coating in aqueous solution; however, it leads to a directional dissolution of Ag NPs in a more strongly basic ammonia solution. The environmentally friendly silica coating process in water is also applied to prepare highly surface-enhanced Raman scattering (SERS)-active Ag@SiO2-SH NPs with different types of Raman molecules for highly sensitive SERS-based applications in various fields.Various metal (Ag, Au, and Pt)@thiol-functionalized silica (SiO2-SH) nanoparticles (NPs) are successfully prepared at room temperature by a facile, efficient, functional, universal and scalable coating process in alcohol-free aqueous solution using pre-hydrolyzed 3-(mercaptopropyl)trimethoxysilane (MPTMS). The controlled pre-hydrolysis of the silane precursor in water and the consecutive condensation processes are the key to achieve the effective and uniform silica coating on metal NPs in aqueous solution. The thickness of the silica shell is tuned by simply varying the coating time. The silica shell can act as an effective protecting layer for Ag NPs in Ag@SiO2-SH NPs under conditions for silica coating in aqueous solution; however, it leads to a directional dissolution of Ag NPs in a more strongly basic ammonia solution. The environmentally friendly silica coating process in water is also applied to prepare highly surface-enhanced Raman scattering (SERS)-active Ag@SiO2-SH NPs with different types of Raman molecules for highly sensitive SERS-based applications in various fields. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr03306j

Effective removal of tetracycline from aqueous solution using activated carbon prepared from tomato (Lycopersicon esculentum Mill.) industrial processing waste.

PubMed

Sayğılı, Hasan; Güzel, Fuat

2016-09-01

Activated carbon (TAC) prepared under optimized conditions with ZnCl2 activation from a new precursor; tomato industrial processing waste (TW), was applied as an adsorbent to remove tetracycline (TC) from aqueous solution. The factors (TAC dosage, initial TC concentration, contact time, ionic strength and solution temperature) affecting the adsorption process were examined at natural pH (5.7) of TAC-TC system in aqueous solution. Kinetic data was found to be best complied by the pseudo-second order model. The isotherm analysis indicated that the equilibrium data could be represented by the Langmuir model. The maximum adsorption capacity was identified as 500.0mgg(-1) at 308K. Copyright © 2016 Elsevier Inc. All rights reserved.

Estimation of quantum yields of weak fluorescence from eosin Y dimers formed in aqueous solutions.

PubMed

Enoki, Masami; Katoh, Ryuzi

2018-05-17

We studied the weak fluorescence from the dimer of eosin Y (EY) in aqueous solutions. We used a newly developed ultrathin optical cell with a thickness ranging from of the order of microns to several hundreds of microns to successfully measure the fluorescence spectra of highly concentrated aqueous solutions of EY without artifacts caused by the reabsorption of fluorescence. The spectra we obtained were similar to the fluorescence spectrum of the EY monomer; almost no fluorescence was observed from the EY dimer. By a careful comparison of the spectra of solutions at low and high concentrations of EY, we succeeded in extracting the fluorescence spectrum of the EY dimer. The fluorescence quantum yield of the EY dimer was estimated to be 0.005.

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.

Capillary electrophoresis of chitooligosaccharides in acidic solution: simple determination using a quaternary-ammonium-modified column and indirect photometric detection with crystal violet.

PubMed

Hattori, Toshiaki; Anraku, Nobuhiro; Kato, Ryo

2010-02-01

Five chitosan oligosaccharides were separated in acidic aqueous solution by capillary electrophoresis (CE) with indirect photometric detection using a positively coated capillary. Electrophoretic mobility of the chitooligosaccharides (COSs) depended on the number of monomer units in acidic aqueous solution, similar to other polyelectrolyte oligomers. The separation was developed in nitric acid aqueous solution at pH 3.0 with 1 mM Crystal Violet, using a capillary positively coated with N-trimethoxypropyl-N,N,N-trimethylammonium chloride. The limit of the detection for chitooligosaccharides with two to six saccharide chains was less than 5 microM. CE determination of an enzymatically hydrolyzed COS agreed with results from HPLC. 2009 Elsevier B.V. All rights reserved.

Field effects in graphene in an interface contact with aqueous solutions of acetic acid and potassium hydroxide

NASA Astrophysics Data System (ADS)

Butko, A. V.; Butko, V. Yu.; Lebedev, S. P.; Lebedev, A. A.; Kumzerov, Yu. A.

2017-10-01

For the creation of new promising chemical sensors, it is very important to study the influence of the interface between graphene and aqueous solutions of acids and alkalis on the transistor characteristics of graphene. Transistor structures on the basis of graphene grown by thermal decomposition of silicon carbide were created and studied. For the interface of graphene with aqueous solutions of acetic acid and potassium hydroxide in the transistor geometry, with a variation in the gate-to-source voltage, the field effect corresponding to the hole type of charge carriers in graphene was observed. It is established that an increase in the concentration of molecular ions in these solutions leads to an increase in the dependence of the resistance of the transistor on the gate voltage.

Flexible ITO-free organic solar cells applying aqueous solution-processed V2O5 hole transport layer: An outdoor stability study

NASA Astrophysics Data System (ADS)

Lima, F. Anderson S.; Beliatis, Michail J.; Roth, Bérenger; Andersen, Thomas R.; Bortoti, Andressa; Reyna, Yegraf; Castro, Eryza; Vasconcelos, Igor F.; Gevorgyan, Suren A.; Krebs, Frederik C.; Lira-Cantu, Mónica

2016-02-01

Solution processable semiconductor oxides have opened a new paradigm for the enhancement of the lifetime of thin film solar cells. Their fabrication by low-cost and environmentally friendly solution-processable methods makes them ideal barrier (hole and electron) transport layers. In this work, we fabricate flexible ITO-free organic solar cells (OPV) by printing methods applying an aqueous solution-processed V2O5 as the hole transport layer (HTL) and compared them to devices applying PEDOT:PSS. The transparent conducting electrode was PET/Ag/PEDOT/ZnO, and the OPV configuration was PET/Ag/PEDOT/ZnO/P3HT:PC60BM/HTL/Ag. Outdoor stability analyses carried out for more than 900 h revealed higher stability for devices fabricated with the aqueous solution-processed V2O5.

Rate constant for reaction of vitamin C with protein radicals in γ-irradiated aqueous albumin solution at 295 K

NASA Astrophysics Data System (ADS)

Miyazaki, Tetsuo; Yoshimura, Toru; Mita, Kazuya; Suzuki, Keiji; Watanabe, Masami

1995-02-01

When an aqueous solution of albumin (0.1 kg dm -3) is irradiated by γ-rays at 295 K, albumin radicals with a long lifetime are observed by ESR. The reaction of vitamin C with the albumin radicals has been studied at 295 K in the albumin solution, which is considered as a model of cells. The rate constant for the reaction of vitamin C with the albumin radicals was measured as 0.014 dm 3 mol -1 s -1, which is much smaller than the reported rate constants (10 6-10 10 dm 3 mol -1 s -1) for the reaction of vitamin C with radicals in a dilute aqueous solution. The small rate constant for the reaction of vitamin C is ascribed to the reaction in polymer coils in the albumin solution, since vitamin C and albumin radicals diffuse very slowly in the coils.

Recovery of metals from simulant spent lithium-ion battery as organophosphonate coordination polymers in aqueous media.

PubMed

Perez, Emilie; Andre, Marie-Laure; Navarro Amador, Ricardo; Hyvrard, François; Borrini, Julien; Carboni, Michaël; Meyer, Daniel

2016-11-05

An innovative approach is proposed for the recycling of metals from a simulant lithium-ion battery (LIBs) waste aqueous solution. Phosphonate organic linkers are introduced as precipitating agents to selectively react with the metals to form coordination polymers from an aqueous solution containing Ni, Mn and Co in a hydrothermal process. The supernatant is analyzed by ICP-AES to quantify the efficiency and the selectivity of the precipitation and the materials are characterized by Scanning Electron Microscopy (SEM), Powder X-Ray Diffraction (PXRD), Thermogravimetric Analyses (TGA) and nitrogen gas sorption (BET). Conditions have been achieved to selectively precipitate Manganese or Manganese/Cobalt from this solution with a high efficiency. This work describes a novel method to obtain potentially valuable coordination polymers from a waste metal solution that can be generalized on any waste solution. Copyright © 2016 Elsevier B.V. All rights reserved.

Diffusivity of nitrous oxide in aqueous solutions of N-methyldiethanolamine and diethanolamine from 293 to 368 K

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

Tamimi, A.; Rinker, E.B.; Sandall, O.C.

1994-04-01

The diffusion coefficients for nitrous oxide in aqueous solutions of diethanolamine (DEA) and N-methyldiethanolamine (MDEA) were determined using a wetted-sphere absorber over the temperature range 293--368 K. The ranges of amine concentrations covered in the experiments were 10--30 mass % for DEA and 10--50 mass % for MDEA. The diffusion coefficients indicated a linear dependence on amine concentration, but the temperature dependence was nonlinear. It was found that the diffusivity of N[sub 2]O in aqueous DEA is always less than that in aqueous MDEA under equivalent conditions of amine concentration and temperature.

Solubilities of selected organic electronic materials in pressurized hot water and estimations of aqueous solubilities at 298.15 K.

PubMed

Karásek, Pavel; Hohnová, Barbora; Planeta, Josef; Št'avíková, Lenka; Roth, Michal

2013-02-01

Increasing production and disposal of organic light-emitting diode (OLED) displays for smartphones and tablets may have impact on the environment depending on the aqueous solubility of the pertinent chemicals. Here, aqueous solubilities are presented for several compounds, mostly aromatic amines, used as hole transport materials in the OLED displays. Solute selection includes 1,4-bis(diphenylamino)benzene, tetra-N-phenylbenzidine, 4,4'-bis(N-carbazolyl)-1,1'-biphenyl, 1,3,5-tris(diphenylamino)benzene, and 9,10-bis(phenylethynyl)anthracene. The solubilities are those in pressurized hot water (PHW), i.e., measured at elevated temperature (up to 260 °C) and pressure. The semi-quantitative estimates of room-temperature solubilities of the solutes have been obtained from extrapolations of the solubilities in PHW. For the compounds studied, the estimated aqueous solubilities at room temperature do not exceed 2×10(-11) g of the solute per 1 kg of water. Aqueous solubilities of triphenylamine have also been measured and used to upgrade a recent group-contribution model of aqueous solubilities of organic nonelectrolytes with the parameters for the nitrogen atom in aromatic amines. Copyright © 2012 Elsevier Ltd. All rights reserved.

Development of tropine-salt aqueous two-phase systems and removal of hydrophilic ionic liquids from aqueous solution.

PubMed

Wu, Haoran; Yao, Shun; Qian, Guofei; Song, Hang

2016-08-26

A novel aqueous two-phase systems (ATPS) composed of a small molecule organic compound tropine and an organic or inorganic salt aqueous solution has been developed for the first time. The phase behavior of tropine-salt ATPS was systemically investigated and the phase equilibrium data were measured in different temperatures and concentrations and correlated by the Merchuk equation with satisfactory results. The detection of the conductivity and particle size proved the formation of micelle in the process of forming tropine-salt ATPS. The separation application of the ATPS was assessed with the removal of hydrophilic benzothiazolium-based ionic liquids (ILs) from aqueous solution. The result showed that ILs were effectively extracted into the top tropine-rich phase. Finally, ILs in the top tropine-rich phase were further separated by the means of adsorption-desorption with DM301 macroporous resin and ethanol. The method of novel tropine-salt ATPS combined with adsorption-desorption is demonstrated a promising alternative thought and approach for the removal or recovery of hydrophilic compounds from aqueous media and also could provide a potential application for bio-separation. Copyright © 2016. Published by Elsevier B.V.

40 CFR 180.1237 - Sodium metasilicate; exemption from the requirement of a tolerance.

Code of Federal Regulations, 2010 CFR

2010-07-01

... PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN... aqueous solution. (b) An exemption from the requirement of a tolerance is established for residues of... not exceed 2.41% by weight in aqueous solution. [71 FR 19441, Apr. 14, 2006] ...

40 CFR 180.1237 - Sodium metasilicate; exemption from the requirement of a tolerance.

Code of Federal Regulations, 2011 CFR

2011-07-01

... PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN... aqueous solution. (b) An exemption from the requirement of a tolerance is established for residues of... not exceed 2.41% by weight in aqueous solution. [71 FR 19441, Apr. 14, 2006] ...

Suspension and Characterization of Aqueous C60 Nanomaterials in Natural and Engineered Waters

EPA Science Inventory

Many current studies on the aqueous suspension of fullerene (aqu/C60) have used deionized water or simple salt solutions, and as a result little is know about the suspension of fullerene nanomatierals under environmentally relevant conditions, such as solutions that contain organ...

A COMPOSITE HOLLOW FIBER MEMBRANE-BASED PERVAPORATION PROCESS FOR SEPARATION OF VOCS FROM AQUEOUS SURFACTANT SOLUTIONS. (R825511C027)

EPA Science Inventory

The separation and recovery of VOCs from surfactant-containing aqueous solutions by a composite hollow fiber membrane-based pervaporation process has been studied. The process employed hydrophobic microporous polypropylene hollow fibers having a thin plasma polymerized silicon...

SEPARATION OF VOLATILE ORGANIC COMPOUNDS FROM AQUEOUS SOLUTIONS BY PERVAPORATION USING S-B-S BLOCK COPOLYMER MEMBRANES.

EPA Science Inventory

Composite membranes of a block copolymer of styrene and butadiene (S-B-S) were cast on highly porous, hydrophobic thin films of PTFE, and used for the separation and recovery of volatile organic compounds (VOCs) from aqueous solutions by pervaporation. Trichloroethane, trichloroe...

21 CFR 522.380 - Chloral hydrate, pentobarbital, and magnesium sulfate sterile aqueous solution.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Chloral hydrate, pentobarbital, and magnesium... INJECTABLE DOSAGE FORM NEW ANIMAL DRUGS § 522.380 Chloral hydrate, pentobarbital, and magnesium sulfate sterile aqueous solution. (a) [Reserved] (b)(1) Specifications. Chloral hydrate, pentobarbital, and...

21 CFR 522.380 - Chloral hydrate, pentobarbital, and magnesium sulfate sterile aqueous solution.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Chloral hydrate, pentobarbital, and magnesium... INJECTABLE DOSAGE FORM NEW ANIMAL DRUGS § 522.380 Chloral hydrate, pentobarbital, and magnesium sulfate sterile aqueous solution. (a) [Reserved] (b)(1) Specifications. Chloral hydrate, pentobarbital, and...

21 CFR 522.380 - Chloral hydrate, pentobarbital, and magnesium sulfate sterile aqueous solution.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Chloral hydrate, pentobarbital, and magnesium... INJECTABLE DOSAGE FORM NEW ANIMAL DRUGS § 522.380 Chloral hydrate, pentobarbital, and magnesium sulfate sterile aqueous solution. (a) [Reserved] (b)(1) Specifications. Chloral hydrate, pentobarbital, and...

21 CFR 522.380 - Chloral hydrate, pentobarbital, and magnesium sulfate sterile aqueous solution.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Chloral hydrate, pentobarbital, and magnesium... INJECTABLE DOSAGE FORM NEW ANIMAL DRUGS § 522.380 Chloral hydrate, pentobarbital, and magnesium sulfate sterile aqueous solution. (a) [Reserved] (b)(1) Specifications. Chloral hydrate, pentobarbital, and...

SEPARATION OF VOLATILE ORGANIC COMPOUNDS FROM AQUEOUS SOLUTIONS BY PERVAPORATION USING S-B-S BLOCK COPOLYMER MEMBRANES

EPA Science Inventory

Composite membranes of a block copolymer of styrene and butadiene (S-B-S) were cast on highly porous, hydrophobic thin films of PTFE and used for the separation and recovery of volatile organic compounds (VOCs) from aqueous solutions by pervaporation. Trichloroethane, trichloroe...

CESIUM RECOVERY FROM AQUEOUS SOLUTIONS

DOEpatents

Goodall, C.A.

1960-09-13

A process is given for precipitating cesium on zinc ferricyanide (at least 0.0004 M) from aqueous solutions containing mineral acid in a concentration of from 0.2 N acidity to 0.61 N acid-deficiency and advantageously, but not necessarily, also aluminum nitrate in a concentration of from l to 2.5 M.

Recovery of uranium values

DOEpatents

Brown, K. B.; Crouse, Jr., D. J.; Moore, J. G.

1959-03-10

A liquid-liquid extraction method is presented for recovering uranium values from an aqueous acidic solution by means of certain high molecular weight amine fn the amine classes of primary, secondary, heterocyclic secondary, tertiary, or heterocyclic tertiary. The uranium bearing aqueous acidic solution is contacted with the selected anine dissolved in a nonpolar waterimmiscible organfc solvent such as kerosene. The uranium which is substantially completely extracted by the organic phase may be stripped therefrom by water, and recovered from the aqueous phase by treatment into ammonia to precipitate ammonium diuranate.

RECOVERY OF URANIUM VALUES

DOEpatents

Brown, K.B.; Crouse, D.J. Jr.; Moore, J.G.

1959-03-10

A liquid-liquid extraction method is presented for recovering uranium values from an aqueous acidic solution by means of certain high molecular weight amine in the amine classes of primary, secondary, heterocyclic secondary, tertiary, or heterocyclic tertiary. The uranium bearing aqueous acidic solution is contacted with the selected amine dissolved in a nonpolar water-immiscible organic solvent such as kerosene. The uranium which is substantially completely exiracted by the organic phase may be stripped therefrom by waters and recovered from the aqueous phase by treatment into ammonia to precipitate ammonium diuranate.

Non-aqueous solution preparation of doped and undoped lixmnyoz

DOEpatents

Boyle, Timothy J.; Voigt, James A.

1997-01-01

A method for generation of phase-pure doped and undoped Li.sub.x Mn.sub.y O.sub.z precursors. The method of this invention uses organic solutions instead of aqueous solutions or nonsolution ball milling of dry powders to produce phase-pure precursors. These precursors can be used as cathodes for lithium-polymer electrolyte batteries. Dopants may be homogeneously incorporated to alter the characteristics of the powder.

Predicting adsorptive removal of chlorophenol from aqueous solution using artificial intelligence based modeling approaches.

PubMed

Singh, Kunwar P; Gupta, Shikha; Ojha, Priyanka; Rai, Premanjali

2013-04-01

The research aims to develop artificial intelligence (AI)-based model to predict the adsorptive removal of 2-chlorophenol (CP) in aqueous solution by coconut shell carbon (CSC) using four operational variables (pH of solution, adsorbate concentration, temperature, and contact time), and to investigate their effects on the adsorption process. Accordingly, based on a factorial design, 640 batch experiments were conducted. Nonlinearities in experimental data were checked using Brock-Dechert-Scheimkman (BDS) statistics. Five nonlinear models were constructed to predict the adsorptive removal of CP in aqueous solution by CSC using four variables as input. Performances of the constructed models were evaluated and compared using statistical criteria. BDS statistics revealed strong nonlinearity in experimental data. Performance of all the models constructed here was satisfactory. Radial basis function network (RBFN) and multilayer perceptron network (MLPN) models performed better than generalized regression neural network, support vector machines, and gene expression programming models. Sensitivity analysis revealed that the contact time had highest effect on adsorption followed by the solution pH, temperature, and CP concentration. The study concluded that all the models constructed here were capable of capturing the nonlinearity in data. A better generalization and predictive performance of RBFN and MLPN models suggested that these can be used to predict the adsorption of CP in aqueous solution using CSC.

Understanding the dissolution of α-zein in aqueous ethanol and acetic acid solutions.

PubMed

Li, Yunqi; Li, Ji; Xia, Qiuyang; Zhang, Boce; Wang, Qin; Huang, Qingrong

2012-10-04

Zein is a corn prolamin that has broad industrial applications because of its unique physical properties. Currently, the high cost of extraction and purification, which is directly related to the dispersion of zein in different solvents, is the major bottleneck of the zein industry. Solution behaviors of zein have been studied for a long time. However, the physical nature of zein in different solvents remains unclear. In this study, small-angle X-ray scattering (SAXS), static light scattering (SLS), and rheology were combined to study the structure and protein-solvent interaction of α-zein in both acetic acid and aqueous ethanol solutions. We found that the like-dissolve-like rule, the partial unfolding, and the protonation of zein are all critical to understanding the solution behaviors. Zein holds an elongated conformation (i.e., prolate ellipsoid) in all solutions, as revealed from SAXS data. There is an "aging effect" for zein in aqueous ethanol solutions, as evidenced by the transition of Newtonian rheological profiles for fresh zein solutions to the non-Newtonian shear thinning behavior for zein solutions after storage at room temperature for 24 h. Such shear thinning behavior becomes more pronounced for zein solutions at higher concentrations. The SLS results clearly show that acetic acid is a better solvent to dissolve zein than aqueous ethanol solution, as supported by a more negative second virial coefficient. This is majorly caused by the protonation of the protein, which was further verified by the dissolution of zein in water (a nonsolvent for zein) with the addition of acids.

Application of molecular dynamics simulations in molecular property prediction II: diffusion coefficient.

PubMed

Wang, Junmei; Hou, Tingjun

2011-12-01

In this work, we have evaluated how well the general assisted model building with energy refinement (AMBER) force field performs in studying the dynamic properties of liquids. Diffusion coefficients (D) have been predicted for 17 solvents, five organic compounds in aqueous solutions, four proteins in aqueous solutions, and nine organic compounds in nonaqueous solutions. An efficient sampling strategy has been proposed and tested in the calculation of the diffusion coefficients of solutes in solutions. There are two major findings of this study. First of all, the diffusion coefficients of organic solutes in aqueous solution can be well predicted: the average unsigned errors and the root mean square errors are 0.137 and 0.171 × 10(-5) cm(-2) s(-1), respectively. Second, although the absolute values of D cannot be predicted, good correlations have been achieved for eight organic solvents with experimental data (R(2) = 0.784), four proteins in aqueous solutions (R(2) = 0.996), and nine organic compounds in nonaqueous solutions (R(2) = 0.834). The temperature dependent behaviors of three solvents, namely, TIP3P water, dimethyl sulfoxide, and cyclohexane have been studied. The major molecular dynamics (MD) settings, such as the sizes of simulation boxes and with/without wrapping the coordinates of MD snapshots into the primary simulation boxes have been explored. We have concluded that our sampling strategy that averaging the mean square displacement collected in multiple short-MD simulations is efficient in predicting diffusion coefficients of solutes at infinite dilution. Copyright © 2011 Wiley Periodicals, Inc.

Ditetraalkylammonium amino acid ionic liquids as CO₂ absorbents of high capacity.

PubMed

Ma, Jing-Wen; Zhou, Zheng; Zhang, Feng; Fang, Cheng-Gang; Wu, You-Ting; Zhang, Zhi-Bing; Li, Ai-Min

2011-12-15

By grafting butyl or ethyl onto tetramethylethylenediamine, quaternary ammonium salts with two positive charge centers were formed at the first step. Metathesis with Ag(2)O followed. Through neutralization with glycine, l-alanine, or valine, a series of new ditetraalkylammonium amino acid ionic liquids (DILs) for CO(2) capture were generated. The structures of DILs, as shown in Figure 1, were verified by using (1)H NMR and EA. These DILs were found to be of quite high viscosity which militated against their industrial application in CO(2) removal. Drawing on the experience of mixed amines' aqueous solutions, these DILs were blended with water or N-methyldiethanolamine (MDEA) aqueous solutions to act as special absorbents of CO(2). Using a Double-Tank Absorption System, the absorption performance of these DIL solutions was investigated in detail. The experimental results indicated that among the three aqueous solutions of DILs (20%, 40%, and 80 wt %), the solution of 40% DIL had a higher absorption rate of CO(2) than the other two, demonstrating the different effects of concentration and viscosity on the absorption. The solution of 40% DIL or the 15% DIL + 15% MDEA had much higher capacity for CO(2) than the corresponding monocation tetraalkylammonium AAILs, due to the special structure of the dication which could influence the solubility of CO(2) in the aqueous solution.

Sucrose diffusion in aqueous solution

PubMed Central

Murray, Benjamin J.

2016-01-01

The diffusion of sugar in aqueous solution is important both in nature and in technological applications, yet measurements of diffusion coefficients at low water content are scarce. We report directly measured sucrose diffusion coefficients in aqueous solution. Our technique utilises a Raman isotope tracer method to monitor the diffusion of non-deuterated and deuterated sucrose across a boundary between the two aqueous solutions. At a water activity of 0.4 (equivalent to 90 wt% sucrose) at room temperature, the diffusion coefficient of sucrose was determined to be approximately four orders of magnitude smaller than that of water in the same material. Using literature viscosity data, we show that, although inappropriate for the prediction of water diffusion, the Stokes–Einstein equation works well for predicting sucrose diffusion under the conditions studied. As well as providing information of importance to the fundamental understanding of diffusion in binary solutions, these data have technological, pharmaceutical and medical implications, for example in cryopreservation. Moreover, in the atmosphere, slow organic diffusion may have important implications for aerosol growth, chemistry and evaporation, where processes may be limited by the inability of a molecule to diffuse between the bulk and the surface of a particle. PMID:27364512

Unique heating curves generated by radiofrequency electric-field interactions with semi-aqueous solutions

NASA Astrophysics Data System (ADS)

Lara, Nadia C.; Haider, Asad A.; Wilson, Lon J.; Curley, Steven A.; Corr, Stuart J.

2017-01-01

Aqueous and nanoparticle-based solutions have been reported to heat when exposed to an alternating radiofrequency (RF) electric-field. Although the theoretical models have been developed to accurately model such a behavior given the solution composition as well as the geometrical constraints of the sample holder, these models have not been investigated across a wide-range of solutions where the dielectric properties differ, especially with regard to the real permittivity. In this work, we investigate the RF heating properties of non-aqueous solutions composed of ethanol, propylene glycol, and glycine betaine with and without varying amounts of NaCl and LiCl. This allowed us to modulate the real permittivity across the range 25-132, as well as the imaginary permittivity across the range 37-177. Our results are in excellent agreement with the previously developed theoretical models. We have shown that different materials generate unique RF heating curves that differ from the standard aqueous heating curves. The theoretical model previously described is robust and accounts for the RF heating behavior of materials with a variety of dielectric properties, which may provide applications in non-invasive RF cancer hyperthermia.

On irreversible adsorption of electron-donating compounds in aqueous solution

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

Tamon, Hajime; Atsushi, Masanori; Okazaki, Morio

Activated carbons and synthetic adsorbents have been used for liquid purification and wastewater treatment. The feasibility of an adsorption process depends greatly on the cost of regeneration of spent adsorbents. If irreversible adsorption occurs, regeneration of spent adsorbent is very difficult. Hence, it is very important to understand why irreversible adsorption appears in aqueous solution. In the adsorption of electron-donating compounds such as phenol, aniline, L-phenylalanine, and L-tyrosine from aqueous solution, irreversibility was observed on activated carbon and graphite. The compounds, except L-tyrosine, were reversibly adsorbed on a synthetic adsorbent. In the case where the carbonaceous adsorbents contacted the aqueousmore » solution containing electron-donating compounds for a long time, the irreversible amount adsorbed increased with the contact time. A two-state adsorption model was used to explain why the irreversible adsorption of electron-donating compound appears in aqueous solution. First, the compound is adsorbed in the precursor state for irreversible adsorption, and then moves into its irreversible state over a potential energy barrier after a long contact time. The appearance of irreversible adsorption was qualitatively explained by the two-state adsorption model.« less

Cell separations and the demixing of aqueous two phase polymer solutions in microgravity

NASA Technical Reports Server (NTRS)

Brooks, Donald E.; Bamberger, Stephan; Harris, J. M.; Van Alstine, James M.

1991-01-01

Partition in phase separated aqueous polymer solutions is a cell separation procedure thought to be adversely influenced by gravity. In preparation for performing cell partitioning experiments in space, and to provide general information concerning the demixing of immiscible liquids in low gravity, a series of phase separated aqueous polymer solutions have been flown on two shuttle flights. Fluorocarbon oil and water emulsions were also flown on the second flight. The aqueous polymer emulsions, which in one g demix largely by sedimentation and convection due to the density differences between the phases, demixed more slowly than on the ground and the final disposition of the phases was determined by the wetting of the container wall by the phases. The demixing behavior and kinetics were influenced by the phase volume ratio, physical properties of the systems and chamber wall interaction. The average domain size increased linearly with time as the systems demixed.

Nanocellular foam with solid flame retardant

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

Chen, Liang; Kelly-Rowley, Anne M.; Bunker, Shana P.

Prepare nanofoam by (a) providing an aqueous solution of a flame retardant dissolved in an aqueous solvent, wherein the flame retardant is a solid at 23.degree. C. and 101 kiloPascals pressure when in neat form; (b) providing a fluid polymer composition selected from a solution of polymer dissolved in a water-miscible solvent or a latex of polymer particles in a continuous aqueous phase; (c) mixing the aqueous solution of flame retardant with the fluid polymer composition to form a mixture; (d) removing water and, if present, solvent from the mixture to produce a polymeric composition having less than 74 weight-percentmore » flame retardant based on total polymeric composition weight; (e) compound the polymeric composition with a matrix polymer to form a matrix polymer composition; and (f) foam the matrix polymer composition into nanofoam having a porosity of at least 60 percent.« less

Electronic structures and spectra of two antioxidants: uric acid and ascorbic acid

NASA Astrophysics Data System (ADS)

Shukla, M. K.; Mishra, P. C.

1996-04-01

Electronic absorption and fluorescence spectra of aqueous solutions of two well known antioxidants, uric acid and ascorbic acid (vitamin C), have been studied at different pH. The observed spectra have been interpreted in terms of neutral and anionic forms of the molecules with the help of molecular orbital calculations. The N 3 site of uric acid has been shown to be the most acidic. Fluorescence of uric acid seems to originate from an anion of the molecule in a wide pH range. Around pH 3, both the neutral and anionic forms of ascorbic acid appear to be present in aqueous solutions. In aqueous media, ascorbic acid appears to get converted easily to its dehydro form and this conversion does not seem to be reversible. An anion of dehydroascorbic acid seems to be formed on heating dehydroascorbic acid in aqueous solutions.

Osmotic potential calculations of inorganic and organic aqueous solutions over wide solute concentration levels and temperatures

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

Cochrane, T. T., E-mail: agteca@hotmail.com; Cochrane, T. A., E-mail: tom.cochrane@canterbury.ac.nz

Purpose: To demonstrate that the authors’ new “aqueous solution vs pure water” equation to calculate osmotic potential may be used to calculate the osmotic potentials of inorganic and organic aqueous solutions over wide ranges of solute concentrations and temperatures. Currently, the osmotic potentials of solutions used for medical purposes are calculated from equations based on the thermodynamics of the gas laws which are only accurate at low temperature and solute concentration levels. Some solutions used in medicine may need their osmotic potentials calculated more accurately to take into account solute concentrations and temperatures. Methods: The authors experimented with their newmore » equation for calculating the osmotic potentials of inorganic and organic aqueous solutions up to and beyond body temperatures by adjusting three of its factors; (a) the volume property of pure water, (b) the number of “free” water molecules per unit volume of solution, “N{sub f},” and (c) the “t” factor expressing the cooperative structural relaxation time of pure water at given temperatures. Adequate information on the volume property of pure water at different temperatures is available in the literature. However, as little information on the relative densities of inorganic and organic solutions, respectively, at varying temperatures needed to calculate N{sub f} was available, provisional equations were formulated to approximate values. Those values together with tentative t values for different temperatures chosen from values calculated by different workers were substituted into the authors’ equation to demonstrate how osmotic potentials could be estimated over temperatures up to and beyond bodily temperatures. Results: The provisional equations formulated to calculate N{sub f}, the number of free water molecules per unit volume of inorganic and organic solute solutions, respectively, over wide concentration ranges compared well with the calculations of N{sub f} using recorded relative density data at 20 °C. They were subsequently used to estimate N{sub f} values at temperatures up to and excess of body temperatures. Those values, together with t values at temperatures up to and in excess of body temperatures recorded in the literature, were substituted in the authors’ equation for the provisional calculation of osmotic potentials. The calculations indicated that solution temperatures and solute concentrations have a marked effect on osmotic potentials. Conclusions: Following work to measure the relative densities of aqueous solutions for the calculation of N{sub f} values and the determination of definitive t values up to and beyond bodily temperatures, the authors’ equation would enable the accurate estimations of the osmotic potentials of wide concentrations of aqueous solutions of inorganic and organic solutes over the temperature range. The study illustrates that not only solute concentrations but also temperatures have a marked effect on osmotic potentials, an observation of medical and biological significance.« less

Ultrafast excited-state deactivation of 9-methylhypoxanthine in aqueous solution: A QM/MM MD study

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

Guo, Xugeng, E-mail: xgguo@henu.edu.cn, E-mail: zhangjinglai@henu.edu.cn; Yuan, Huijuan; An, Beibei

Photoinduced ultrafast non-adiabatic decay of 9-methylhypoxanthine (9MHPX) in aqueous solution was investigated by ab initio surface-hopping dynamics calculations using a combined quantum mechanical/molecular mechanical approach. The absorption spectra of 9MHPX in aqueous solution were also explored by the hybrid cluster-continuum model at the level of time-dependent density functional theory along with the polarizable continuum model (PCM). The static electronic-structure calculations indicate that the absorption spectra of 9MHPX simulated by TD-B3LYP/PCM and TD-X3LYP/PCM can reproduce very well the experimental findings, with the accuracy of about 0.20 eV. According to dynamics simulations, irradiation of 9MHPX populates the bright excited singlet S{sub 1}more » state, which may undergo an ultrafast non-radiative deactivation to the S{sub 0} state. The lifetime of the S{sub 1} state of 9MHPX in aqueous solution is predicted to be 115.6 fs, slightly longer than that in the gas phase (88.8 fs), suggesting that the solvent water has no significant influence on the excited-state lifetime of 9MHPX. Such a behavior in 9MHPX is distinctly different from its parent hypoxanthine keto-N9H tautomer in which the excited-state lifetime of the latter in water solution was remarkably enhanced as compared to the gas phase. The significant difference of the photodynamical behaviors between 9MHPX and keto-N9H can be ascribed to their different hydrogen bond environment in aqueous solution.« less

CdTe1-x S x (x  ⩽  0.05) thin films synthesized by aqueous solution deposition and annealing

NASA Astrophysics Data System (ADS)

Pruzan, Dennis S.; Hahn, Carina E.; Misra, Sudhajit; Scarpulla, Michael A.

2017-11-01

While CdS thin films are commonly deposited from aqueous solutions, CdTe thin films are extremely difficult to deposit directly from aqueous solution. In this work, we report on polycrystalline CdTe1-x S x thin films synthesized via deposition from aqueous precursor solutions followed by annealing treatments and on their physical properties. The deposition method uses spin-coating of alternating Cd2+ and Te2- aqueous solutions and rinse steps to allow formation of the films but to shear off excess reactants and poorly-bonded solids. Films are then annealed in the presence of CdCl2 as is commonly done for CdTe photovoltaic absorber layers deposited by any means. Scanning electron microscopy (SEM) reveals low void fractions and grain sizes up to 4 µm and x-ray diffraction (XRD) shows that the films are primarily cubic CdTe1-x S x (x  ⩽  0.05) with random crystallographic orientation. Optical transmission yields bandgap absorption consistent with a CdTe1-x S x dilute alloy and low-temperature photoluminescence (PL) consists of an emission band centered at 1.35 eV consistent with donor-acceptor pair (DAP) transitions in CdTe1-x S x . Together, the crystalline quality and PL yield from films produced by this method represent an important step towards electroless, ligand-free solution processed CdTe and related alloy thin films suitable for optoelectronic device applications such as thin film heterojunction or nanodipole-based photovoltaics.

Coefficients of interphase distribution and Gibbs energy of the transfer of nicotinic acid from water into aqueous solutions of ethanol and dimethylsulfoxide

NASA Astrophysics Data System (ADS)

Grazhdan, K. V.; Gamov, G. A.; Dushina, S. V.; Sharnin, V. A.

2012-11-01

Coefficients of the interphase distribution of nicotinic acid are determined in aqueous solution systems of ethanol-hexane and DMSO-hexane at 25.0 ± 0.1°C. They are used to calculate the Gibbs energy of the transfer of nicotinic acid from water into aqueous solutions of ethanol and dimethylsulfoxide. The Gibbs energy values for the transfer of the molecular and zwitterionic forms of nicotinic acid are obtained by means of UV spectroscopy. The diametrically opposite effect of the composition of binary solvents on the transfer of the molecular and zwitterionic forms of nicotinic acid is noted.

The surface tension of aqueous solutions of some atmospheric water-soluble organic compounds

NASA Astrophysics Data System (ADS)

Tuckermann, Rudolf; Cammenga, Heiko K.

The surface tensions of aqueous solutions of levoglucosan, 3-hydroxybutanoic acid, 3-hydroxybenzoic acid, azelaic acid, pinonic acid, and humic acid have been measured. These compounds are suggested as model substances for the water-soluble organic compounds (WSOC) in atmospheric aerosols and droplets which may play an important role in the aerosol cycle because of their surface-active potentials. The reductions in surface tension induced by single and mixed WSOC in aqueous solution of pure water is remarkable. However, the results of this investigation cannot explain the strong reduction in surface tension in real cloud and fog water samples at concentrations of WSOC below 1 mg/mL.

Photocatalysis of zinc oxide nanotip array/titanium oxide film heterojunction prepared by aqueous solution deposition

NASA Astrophysics Data System (ADS)

Lee, Ming-Kwei; Lee, Bo-Wei; Kao, Chen-Yu

2017-05-01

A TiO2 film was prepared on indium tin oxide (ITO)/glass by aqueous solution deposition (ASD) with precursors of ammonium hexafluoro-titanate and boric acid at 40 °C. The photocatalysis of annealed TiO2 film increases with increasing growth time and decreases with increasing growth times longer than 60 min. A ZnO nanotip array was prepared on ZnO seed layer/TiO2 film/glass by aqueous solution deposition with precursors of zinc nitrate and ammonium hydroxide at 70 °C. The photocatalysis of ASD-ZnO/ASD-TiO2 film/ITO glass can be better than that of P25.

Fluidized bed gasification of extracted coal

DOEpatents

Aquino, Dolores C.; DaPrato, Philip L.; Gouker, Toby R.; Knoer, Peter

1986-01-01

Coal or similar carbonaceous solids are extracted by contacting the solids in an extraction zone (12) with an aqueous solution having a pH above 12.0 at a temperature between 65.degree. C. and 110.degree. C. for a period of time sufficient to remove bitumens from the coal into said aqueous solution and the extracted solids are then gasified at an elevated pressure and temperature in a fluidized bed gasification zone (60) wherein the density of the fluidized bed is maintained at a value above 160 kg/m.sup.3. In a preferred embodiment of the invention, water is removed from the aqueous solution in order to redeposit the extracted bitumens onto the solids prior to the gasification step.

Surface tension of aqueous solutions of diethanolamine and triethanolamine from 25 C to 50 C

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

Vazquez, G.; Alvarez, E.; Rendo, R.

1996-07-01

Aqueous solutions of alkanolamines such as monoethanolamine (MEA), diethanolamine (DEA), triethanolamine (TEA), N-methyldiethanolamine (MDEA), and 2-amino-2-methyl-1-propanol (AMP) are good solvents for the removal of acid gases such CO{sub 2} and H{sub 2}S from the gas streams of many processes in the natural gas, ammonia synthesis, and some chemical industries. The surface tension of aqueous solutions of diethanolamine and triethanolamine was measured over the entire concentration range at temperatures of 25 C to 50 C. The experimental values were correlated with temperature and with mole fraction. The maximum deviation was in both cases always less than 0.5%.

Continuous air agglomeration method for high carbon fly ash beneficiation

DOEpatents

Gray, McMahon L.; Champagne, Kenneth J.; Finseth, Dennis H.

2000-01-01

The carbon and mineral components of fly ash are effectively separated by a continuous air agglomeration method, resulting in a substantially carboree mineral stream and a highly concentrated carbon product. The method involves mixing the fly ash comprised of carbon and inorganic mineral matter with a liquid hydrocarbon to form a slurry, contacting the slurry with an aqueous solution, dispersing the hydrocarbon slurry into small droplets within the aqueous solution by mechanical mixing and/or aeration, concentrating the inorganic mineral matter in the aqueous solution, agglomerating the carbon and hydrocarbon in the form of droplets, collecting the droplets, separating the hydrocarbon from the concentrated carbon product, and recycling the hydrocarbon.

PRECIPITATION METHOD OF SEPARATING PLUTONIUM FROM CONTAMINATING ELEMENTS

DOEpatents

Sutton, J.B.

1958-02-18

This patent relates to an improved method for the decontamination of plutonium. The process consists broadly in an improvement in a method for recovering plutonium from radioactive uranium fission products in aqueous solutions by decontamination steps including byproduct carrier precipitation comprising the step of introducing a preformed aqueous slurry of a hydroxide of a metal of group IV B into any aqueous acidic solution which contains the plutonium in the hexavalent state, radioactive uranium fission products contaminant and a by-product carrier precipitate and separating the metal hydroxide and by-product precipitate from the solution. The process of this invention is especially useful in the separation of plutonium from radioactive zirconium and columbium fission products.

Influence of formulation and processing variables on properties of itraconazole nanoparticles made by advanced evaporative precipitation into aqueous solution.

PubMed

Bosselmann, Stephanie; Nagao, Masao; Chow, Keat T; Williams, Robert O

2012-09-01

Nanoparticles, of the poorly water-soluble drug, itraconazole (ITZ), were produced by the Advanced Evaporative Precipitation into Aqueous Solution process (Advanced EPAS). This process combines emulsion templating and EPAS processing to provide improved control over the size distribution of precipitated particles. Specifically, oil-in-water emulsions containing the drug and suitable stabilizers are sprayed into a heated aqueous solution to induce precipitation of the drug in form of nanoparticles. The influence of processing parameters (temperature and volume of the heated aqueous solution; type of nozzle) and formulation aspects (stabilizer concentrations; total solid concentrations) on the size of suspended ITZ particles, as determined by laser diffraction, was investigated. Furthermore, freeze-dried ITZ nanoparticles were evaluated regarding their morphology, crystallinity, redispersibility, and dissolution behavior. Results indicate that a robust precipitation process was developed such that size distribution of dispersed nanoparticles was shown to be largely independent across the different processing and formulation parameters. Freeze-drying of colloidal dispersions resulted in micron-sized agglomerates composed of spherical, sub-300-nm particles characterized by reduced crystallinity and high ITZ potencies of up to 94% (w/w). The use of sucrose prevented particle agglomeration and resulted in powders that were readily reconstituted and reached high and sustained supersaturation levels upon dissolution in aqueous media.

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

PubMed

Rogers, R D; Griffin, S T

1998-06-26

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

The effect of physiologic aqueous solutions on the perovskite material lead-lanthanum-zirconium titanate (PLZT): potential retinotoxicity.

PubMed

Foster, William J; Meen, James K; Fox, Donald A

2013-03-01

Perovskite compounds, including lead-lanthanum-zirconium titanate (PLZT), have wide technological application because of their unique physical properties. The use of PLZT in neuro-prosthetic systems, such as retinal implants, has been discussed in a number of publications. Since inorganic lead is a retinotoxic compound that produces retinal degeneration, the long-term stability of PLZT in aqueous biological solutions must be determined. We evaluated the stability and effects of prolonged immersion of a PLZT-coated crystal in a buffered balanced salt solution. Scanning Electron Microscopy and Electron Dispersive Spectroscopy (EDS) using a JEOL JSM 5410 microscope equipped with EDS were utilized to evaluate the samples before and after prolonged immersion. We found that lead and other constituents of PLZT leached into the surrounding aqueous medium. By comparing the unit cell of PLZT with that of CaTiO(3), which has been found to react with aqueous fluids, Lead is in the same site in PLZT as Ca is in CaTiO(3). It is thus reasonable that PLZT will react with aqueous solutions. The results suggest that PLZT must either be coated with a protective layer or is not appropriate for long-term in vivo or in vitro biological applications.

The effect of physiologic aqueous solutions on the perovskite material lead-lanthanum-zirconium titanate (PLZT)

PubMed Central

Foster, William J.; Meen, James K.; Fox, Donald A.

2016-01-01

Context Perovskite compounds, including Lead-Lanthanum-Zirconium Titanate (PLZT), have wide technological application because of their unique physical properties. The use of PLZT in neuro-prosthetic systems, such as retinal implants, have been discussed in a number of publications. Since inorganic lead is a retinotoxic compound that produces retinal degeneration, the long-term stability of PLZT in aqueous biological solutions must be determined. Objective We evaluated the stability and effects of prolonged immersion of a PLZT-coated crystal in a buffered balanced salt solution. Materials and Methods Scanning Electron Microscopy and Electron Dispersive Spectroscopy (EDS) using a JEOL JSM 5410 microscope equipped with EDS were utilized to evaluate the samples before and after prolonged immersion. Results We found that lead and other constituents of PLZT leached into the surrounding aqueous medium. Discussion By comparing the unit cell of PLZT with that of CaTiO3, which has been found to react with aqueous fluids, Lead is in the same site in PLZT as Ca is in CaTiO3. It is thus reasonable that PLZT will react with aqueous solutions. Conclusion The results suggest that PLZT must either be coated with a protective layer or is not appropriate for long-term in vivo or in vitro biological applications. PMID:22697294

Aggregation and Deposition of C60 in Aqueous Systems

EPA Science Inventory

The extremely low water solubility of many fullerenes precludes aqueous solution processing for engineering applications and minimizes the potential for fullerene environmental effects in aqueous environments. However, studies have shown that C60 fullerene can form stable colloi...

Removal of uranium from aqueous HF solutions

DOEpatents

Pulley, Howard; Seltzer, Steven F.

1980-01-01

This invention is a simple and effective method for removing uranium from aqueous HF solutions containing trace quantities of the same. The method comprises contacting the solution with particulate calcium fluoride to form uranium-bearing particulates, permitting the particulates to settle, and separting the solution from the settled particulates. The CaF.sub.2 is selected to have a nitrogen surface area in a selected range and is employed in an amount providing a calcium fluoride/uranium weight ratio in a selected range. As applied to dilute HF solutions containing 120 ppm uranium, the method removes at least 92% of the uranium, without introducing contaminants to the product solution.

REDUCTION OF ACIDITY OF NITRIC ACID SOLUTIONS BY USE OF FORMALDEHYDE

DOEpatents

Healy, T.V.

1958-05-20

A continuous method is described of concentrating by evaporation and reducing the nitrate ion content of an aqueous solution of metallic salts containing nitric acid not in excess of 8N. It consists of heating the solution and then passing formaldehyde into the heated solution to bring about decomposition of the nitric acid. The evolved gases containing NO are contacted countercurrently with an aqueous metal salt solution containing nitric acid in excess of 8N so as to bring about decomposition of the nitric acid and lower the normality to at least 8N, whereupon it is passed into the body of heated solution.

Calixarene crown ether solvent composition and use thereof for extraction of cesium from alkaline waste solutions

DOEpatents

Moyer, Bruce A.; Sachleben, Richard A.; Bonnesen, Peter V.; Presley, Derek J.

2001-01-01

A solvent composition and corresponding method for extracting cesium (Cs) from aqueous neutral and alkaline solutions containing Cs and perhaps other competing metal ions is described. The method entails contacting an aqueous Cs-containing solution with a solvent consisting of a specific class of lipophilic calix[4]arene-crown ether extractants dissolved in a hydrocarbon-based diluent containing a specific class of alkyl-aromatic ether alcohols as modifiers. The cesium values are subsequently recovered from the extractant, and the solvent subsequently recycled, by contacting the Cs-containing organic solution with an aqueous stripping solution. This combined extraction and stripping method is especially useful as a process for removal of the radionuclide cesium-137 from highly alkaline waste solutions which are also very concentrated in sodium and potassium. No pre-treatment of the waste solution is necessary, and the cesium can be recovered using a safe and inexpensive stripping process using water, dilute (millimolar) acid solutions, or dilute (millimolar) salt solutions. An important application for this invention would be treatment of alkaline nuclear tank wastes. Alternatively, the invention could be applied to decontamination of acidic reprocessing wastes containing cesium-137.

Photochemical method for generating superoxide radicals (O.sub.2.sup.-) in aqueous solutions

DOEpatents

Holroyd, Richard A.; Bielski, Benon H. J.

1980-01-01

A photochemical method and apparatus for generating superoxide radicals (ub.2.sup.-) in an aqueous solution by means of a vacuum-ultraviolet lamp of simple design. The lamp is a microwave powered rare gas device that emits far-ultraviolet light. The lamp includes an inner loop of high purity quartz tubing through which flows an oxygen-saturated sodium formate solution. The inner loop is designed so that the solution is subjected to an intense flux of far-ultraviolet light. This causes the solution to photodecompose and form the product radical (O.sub.2.sup.-).

Changes in the IR Spectra of Aqueous Solutions of Alkali Metal Chlorides during Crystallization

NASA Astrophysics Data System (ADS)

Koroleva, A. V.; Matveev, V. K.; Koroleva, L. A.; Pentin, Yu. A.

2018-02-01

The IR spectra of aqueous solutions of sodium chloride and rubidium chloride with the same concentration of 0.1 M upon freezing are studied in the middle IR region. The changes that occur in the absorption bands of the bending ν2, compound ν2 + νL, and stretching (ν1, 2ν2, and ν3) vibrations of water molecules with gradual crystallization of the solutions are studied. The obtained spectra of crystallized solutions are compared to the IR spectrum of ice Ih. Analysis allows conclusions about the structure of the investigated frozen crystallized solutions.

CONCENTRATION OF Pu USING OXALATE TYPE CARRIER

DOEpatents

Ritter, D.M.; Black, R.P.S.

1960-04-19

A method is given for dissolving and reprecipitating an oxalate carrier precipitate in a carrier precipitation process for separating and recovering plutonium from an aqueous solution. Uranous oxalate, together with plutonium being carried thereby, is dissolved in an aqueous alkaline solution. Suitable alkaline reagents are the carbonates and oxulates of the alkali metals and ammonium. An oxidizing agent selected from hydroxylamine and hydrogen peroxide is then added to the alkaline solution, thereby oxidizing uranium to the hexavalent state. The resulting solution is then acidified and a source of uranous ions provided in the acidified solution, thereby forming a second plutoniumcarrying uranous oxalate precipitate.

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

Hawkins, Cory A.; Bustillos, Christian G.; May, Iain

Conventional solvent extraction of selected f-element cations by bis(2-ethylhexyl)phosphoric acid (HDEHP) yields increased extraction from aqueous to organic solution along the series Np(V) < Cm(III) < Eu(III) < U(VI), with distribution ratios all within two orders of magnitude. However, in the presence of the water-soluble tetradentate Schiff base (N,N'-bis(5-sulfonatosalicylidene)-ethylenediamine or H 2salenSO 3), selective complexation of the two actinyl cations (Np(V) and U(VI)) resulted in an extraction order of Np(V) < U(VI) << Eu(III) < Cm(III). The extraction of neither Cm(III) or Eu(III) by HDEHP are significantly impacted by the presence of the aqueous phase Schiff base. Despite observed hydrolyticmore » decomposition of H 2salenSO 3 in aqueous solutions, the calculated high conditional stability constant (β 11 = 26) for the complex [UO 2(salenSO 3)] 2- demonstrates its capacity for aqueous hold-back of U(VI). UV-visible-NIR spectroscopy of solutions prepared with a Np(VI) stock and H 2salenSO 3 suggest that reduction of Np(VI) to Np(V) by the ligand was rapid, resulting in a pentavalent Np complex that was substantially retained in the aqueous phase. Lastly, results from 1H NMR of aqueous solutions of H 2salenSO 3 with U(VI) and La(III), Eu(III), and Lu(III) provides additional evidence that the ligand readily chelates U(VI), but has only weak interactions with trivalent lanthanide ions.« less

Near-infrared studies of glucose and sucrose in aqueous solutions: water displacement effect and red shift in water absorption from water-solute interaction.

PubMed

Jung, Youngeui; Hwang, Jungseek

2013-02-01

We used near infrared spectroscopy to obtain concentration dependent glucose absorption spectra in aqueous solutions in the near-infrared range (3800-7500 cm(-1)). Here we introduce a new method to obtain reliable glucose absorption bands from aqueous glucose solutions without measuring the water displacement coefficients of glucose separately. Additionally, we were able to extract the water displacement coefficients of glucose, and this may offer a new general method using spectroscopy techniques applicable to other water-soluble materials. We also observed red shifts in the absorption bands of water in the hydration shell around solute molecules, which comes from the contribution of the interacting water molecules around the glucose molecules in solutions. The intensity of the red shift gets larger as the concentration increases, which indicates that as the concentration increases more water molecules are involved in the interaction. However, the red shift in frequency does not seem to depend significantly on the concentration. We also performed the same measurements and analysis with sucrose instead of glucose as solute and compared.

Characterization of Nanoparticles and Colloids in Aquatic Systems 1. Small Angle Neutron Scattering Investigations of Suwannee River Fulvic Acid Aggregates in Aqueous Solutions

NASA Astrophysics Data System (ADS)

Diallo, Mamadou S.; Glinka, Charles J.; Goddard, William A.; Johnson, James H.

2005-10-01

Fulvic acids (FA) and humic acids (HA) constitute 30-50% of dissolved organic matter in natural aquatic systems. In aqueous solutions, a commonly accepted view is that FA and HA exist as soluble macroligands at low concentration and as supramolecular aggregates at higher concentration. The size, shape and structure of these aggregates are still the subject of ongoing debate in the environmental chemistry literature. In this article, we use small angle neutron scattering (SANS) to assess the effects of solute concentration, solution pH and background electrolyte (NaCl) concentration on the structures of Suwannee River FA (SRFA) aggregates in D2O. The qualitative features of the SANS curves and data analysis are not consistent with the view point that SRFA forms micelle-like aggregates as its concentration in aqueous solution increases. We find that SRFA forms fractal aggregates in D20 with size greater than 242 nm. The SRFA aggregates undergo a significant degree of restructuring in compactness as solution pH, solute concentration and NaCl concentration increase.

Markedly lowering the viscosity of aqueous solutions of DNA by additives.

PubMed

Elkin, Igor; Weight, Alisha K; Klibanov, Alexander M

2015-10-15

Aqueous solutions of DNAs, while relevant in drug delivery and as a target of therapies, are often very viscous making them difficult to use. Since less viscous solutions could enable targeted drug delivery and/or therapies, the purpose of the present work was to explore compounds capable of "thinning" such DNA solutions under pharmaceutically relevant conditions. To this end, viscosities of aqueous solutions of DNAs and model polyanions were examined at 25 °C in the absence and presence of a number of bulky organic salts (and related compounds) previously found to substantially lower the viscosities of concentrated protein solutions. Out of two dozen compounds tested, only three were found to be effective; the FDA-approved local anesthetics lidocaine, mepivacaine, and prilocaine at near-isotonic concentrations and pH 6.4 lowered solution viscosity of three different DNAs up to about 20 fold. The observed multi-fold viscosity reductions appear to be due to these bulky organic salts' structure-specific non-covalent binding to nucleotide bases resulting in denaturation (unwinding) to, and stabilization of, single-stranded DNA. Copyright © 2015 Elsevier B.V. All rights reserved.

Method for producing nuclear fuel

DOEpatents

Haas, Paul A.

1983-01-01

Nuclear fuel is made by contacting an aqueous solution containing an actinide salt with an aqueous solution containing ammonium hydroxide, ammonium oxalate, or oxalic acid in an amount that will react with a fraction of the actinide salt to form a precipitate consisting of the hydroxide or oxalate of the actinide. A slurry consisting of the precipitate and solution containing the unreacted actinide salt is formed into drops which are gelled, calcined, and pressed to form pellets.

Applications of ZVMo NMR spectroscopy. 17. ZVMo and UN relaxation time measurements confirming that (Mo(CN)8)U is dodecahedral in aqueous solution

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

Brownlee, R.T.; Shehan, B.P.; Wedd, A.G.

1987-07-01

Variable-temperature NMR line width measurements of ZVMo and UN in aqueous solutions of K4(Mo(CN)8) x 2H2O indicate that the stereochemistry of the (Mo(CN)8)U ion in solution is dodecahedral. A value for the ZVMo quadrupole coupling constant of 3.61 MHz is obtained. 27 references, 1 figure, 1 table.

A Study of the Diffusion, Electrochemical Mobility and Removal of Dissolved Copper in a Saturated Porous Medium.

DTIC Science & Technology

1980-11-01

aqueous solutions : use of activity coefficients in transition-state models: Geochimica et Cosmochimica Acta, v...native state at 25°C at any activity level below 10+46.0 in an aqueous solution . Because such an activity level is impossible, sodium cannot be reduced...stoichiometric coefficients . It is necessary to calculqte the activity coefficients of dissolved copper in the test solutions in order to render an

21 CFR 524.1200b - Kanamycin ophthalmic aqueous solution.

Code of Federal Regulations, 2013 CFR

2013-04-01

..., removal of foreign bodies, and intraocular surgery. Instill a few drops into the affected eye every 3... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Kanamycin ophthalmic aqueous solution. 524.1200b Section 524.1200b Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES...

21 CFR 524.1200b - Kanamycin ophthalmic aqueous solution.

Code of Federal Regulations, 2012 CFR

2012-04-01

..., removal of foreign bodies, and intraocular surgery. Instill a few drops into the affected eye every 3... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Kanamycin ophthalmic aqueous solution. 524.1200b Section 524.1200b Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES...

Effect of pH on the Electrophoretic Mobility of Spores of Bacillus anthracis and Its Surrogates in Aqueous Solutions

EPA Science Inventory

Electrophoretic mobility (EPM) of endospores of Bacillus anthracis and surrogates were measured in aqueous solution across a broad pH range and several ionic strengths. EPM values trended around phylogenetic clustering based on the 16S rRNA gene. Measurements reported here prov...

Hydrogen generation by electrolysis of aqueous organic solutions

NASA Technical Reports Server (NTRS)

Jeffries-Nakamura, Barbara (Inventor); Narayanan, Sekharipuram R. (Inventor); Chun, William (Inventor); Valdez, Thomas I. (Inventor)

2006-01-01

A device for electrolysis of an aqueous solution of an organic fuel. The electrolyte is a solid-state polymer membrane with anode and cathode catalysts on both surfaces for electro-oxidization and electro-reduction. A low-cost and portable hydrogen generator can be made based on the device with organic fuels such as methanol.

Henry’s Law Constant and Overall Mass Transfer Coefficient for Formaldehyde Emission from Small Water Pools under Simulated Indoor Environmental Conditions

EPA Science Inventory

The Henry’s law constant (HLC) and the overall mass transfer coefficient are both important parameters for modeling formaldehyde emissions from aqueous solutions. In this work, the apparent HLCs for aqueous formaldehyde solutions were determined in the concentration range from 0....

The Reaction between Iron(II) Iodide and Potassium Dichromate(VI) in Acidified Aqueous Solution

ERIC Educational Resources Information Center

Talbot, Christopher

2013-01-01

This "Science note" teaching lesson explores the possible reaction between the ions in a reaction mixture consisting of iron(II) iodide and potassium dichromate(VI) in acidified aqueous solution. The electrode potentials will be used to deduce any spontaneous reactions under standard thermodynamic conditions (298 K, 1 bar (approximately…

Regularities in the association of polymethacrylic acid with benzethonium chloride in aqueous solutions

NASA Astrophysics Data System (ADS)

Tugay, A. V.; Zakordonskiy, V. P.

2006-06-01

The association of cationogenic benzethonium chloride with polymethacrylic acid in aqueous solutions was studied by nephelometry, conductometry, tensiometry, viscometry, and pH-metry. The critical concentrations of aggregation and polymer saturation with the surface-active substance were determined. A model describing processes in such systems step by step was suggested.

Hydrogen generation by electrolysis of aqueous organic solutions

NASA Technical Reports Server (NTRS)

Narayanan, Sekharipuram R. (Inventor); Chun, William (Inventor); Jeffries-Nakamura, Barbara (Inventor); Valdez, Thomas I. (Inventor)

2002-01-01

A device for electrolysis of an aqueous solution of an organic fuel. The electrolyte is a solid-state polymer membrane with anode and cathode catalysts on both surfaces for electro-oxidization and electro-reduction. A low-cost and portable hydrogen generator can be made based on the device with organic fuels such as methanol.

Removal of phosphate from aqueous solutions and sewage using natural and surface modified coir pith.

PubMed

Krishnan, K Anoop; Haridas, Ajit

2008-04-01

Iron impregnated coir pith (CP-Fe-I) can be effectively used for the removal of phosphate from aqueous streams and sewage. Iron impregnation on natural coir pith was carried out by drop by drop addition method. The effect of various factors such as pH, initial concentration of phosphate, contact time and adsorbent dose on phosphate adsorption was studied by batch technique. The pH at 3.0 favored the maximum adsorption of phosphate from aqueous solutions. The effect of pH on phosphate adsorption was explained by pH(zpc), phosphate speciation in solution and affinity of anions towards the adsorbent sites. A comparative study of the adsorption of phosphate using CP-Fe-I and CP (coir pith) was made and results show that the former one is five to six times more effective than the latter. Kinetic studies revealed that the adsorption process followed a pseudo-second order kinetic model. Adsorption followed Langmuir isotherm model. Column studies were conducted to examine the utility of the investigated adsorbent for the removal of phosphate from continuously flowing aqueous solutions.

Selective and Sensitive Detection of Heavy Metal Ions in 100% Aqueous Solution and Cells with a Fluorescence Chemosensor Based on Peptide Using Aggregation-Induced Emission.

PubMed

Neupane, Lok Nath; Oh, Eun-Taex; Park, Heon Joo; Lee, Keun-Hyeung

2016-03-15

A fluorescent peptidyl chemosensor for the detection of heavy metal ions in aqueous solution as well as in cells was synthesized on the basis of the peptide receptor for the metal ions using an aggregation-induced emission fluorophore. The peptidyl chemosensor (1) bearing tetraphenylethylene fluorophore showed an exclusively selective turn-on response to Hg(2+) among 16 metal ions in aqueous buffered solution containing NaCl. The peptidyl chemosensor complexed Hg(2+) ions and then aggregated in aqueous buffered solution, resulting in the significant enhancement (OFF-On) of emissions at around 470 nm. The fluorescent sensor showed a highly sensitive response to Hg(2+), and about 1.0 equiv of Hg(2+) was enough for the saturation of the emission intensity change. The detection limit (5.3 nM, R(2) = 0.99) of 1 for Hg(2+) ions was lower than the maximum allowable level of Hg(2+) in drinking water by EPA. Moreover, the peptidyl chemosensor penetrated live cells and detected intracellular Hg(2+) ions by the turn-on response.

Au-nanoparticle-embedded cross-linked gelatin films synthesized on aqueous solution in contact with dielectric barrier discharge

NASA Astrophysics Data System (ADS)

Shirafuji, Tatsuru; Nakamura, Yusuke; Azuma, Shiori; Sotoda, Naoya; Isshiki, Toshiyuki

2018-01-01

A wine-red free-standing thin film has been formed by irradiating dielectric barrier discharge plasma on an aqueous solution containing HAuCl4 and gelatin. The film has a fibrous structure with an inhomogeneous thickness profile and is composed of cross-linked gelatin, as confirmed by optical microscopy and infrared absorption spectroscopy. The film has embedded Au nanoparticles (GNPs), as confirmed by transmission electron microscopy. In the region with a relatively small film thickness, the number density of GNPs is relatively low, and the sizes of GNPs range from 5.3 to 34.3 nm. In the region with a relatively large film thickness, on the other hand, GNPs are highly accumulated, and the sizes of GNPs range from 10.0 to 26.7 nm. The aqueous solution remains transparent even after the film growth process, which indicates that the plasma-induced processes involving GNP formation and film growth are confined near the surface of the aqueous solution. A possible film growth mechanism is discussed on the basis of the experimental results of this study.

Biosorption characteristics of Uranium (VI) from aqueous solution by pollen pini.

PubMed

Wang, Feihong; Tan, Lichao; Liu, Qi; Li, Rumin; Li, Zhanshuang; Zhang, Hongsen; Hu, Songxia; Liu, Lianhe; Wang, Jun

2015-12-01

Uranium biosorption from aqueous solutions by pollen pini (Pinus massoniana pollen) was studied in a bath system. The biosorbent was characterized by Fourier-transform infrared spectroscopy and scanning electron microscope. The influences of pH, contact time and initial uranium concentration at room temperature were investigated and the experimental curves were obtained. The pollen pini exhibited the highest uranium sorption capacity at pH 5.0 after 2 h contact. At pH 2.5 pollen pini also exhibited a good uranium loading capacity (>15%). Therefore biosorption characteristics of uranium from aqueous solution onto pollen pini were examined at pH 2.5 as well. The kinetics followed a pseudo-second-order rate equation and adsorption process was well fitted with the Freundlich isotherm at both pH. The adsorption of uranium by the biosorbent was confirmed by energy dispersive spectroscopy. The present study suggested that pollen pini could be a suitable biosorbent for biosorption uranium (VI) from aqueous solution in a fast, low cost and convenient approach. Copyright © 2015 Elsevier Ltd. All rights reserved.

Hydration and Ion Pairing in Aqueous Mg2+ and Zn2+ Solutions: Force-Field Description Aided by Neutron Scattering Experiments and Ab Initio Molecular Dynamics Simulations.

PubMed

Duboué-Dijon, Elise; Mason, Philip E; Fischer, Henry E; Jungwirth, Pavel

2018-04-05

Magnesium and zinc dications possess the same charge and have an almost identical size, yet they behave very differently in aqueous solutions and play distinct biological roles. It is thus crucial to identify the origins of such different behaviors and to assess to what extent they can be captured by force-field molecular dynamics simulations. In this work, we combine neutron scattering experiments in a specific mixture of H 2 O and D 2 O (the so-called null water) with ab initio molecular dynamics simulations to probe the difference in the hydration structure and ion-pairing properties of chloride solutions of the two cations. The obtained data are used as a benchmark to develop a scaled-charge force field for Mg 2+ that includes electronic polarization in a mean field way. We show that using this electronic continuum correction we can describe aqueous magnesium chloride solutions well. However, in aqueous zinc chloride specific interaction terms between the ions need to be introduced to capture ion pairing quantitatively.

Stable supersaturated aqueous solutions of silatecan 7-t-butyldimethylsilyl-10-hydroxycamptothecin via chemical conversion in the presence of a chemically modified beta-cyclodextrin.

PubMed

Xiang, Tian-Xiang; Anderson, Bradley D

2002-08-01

A method for obtaining clear supersaturated aqueous solutions for parenteral administration of the poorly soluble experimental anti-cancer drug silatecan 7-t-butyldimethylsilyl-10-hydroxycamptothecin (DB-67) has been developed. Equilibrium solubilities of DB-67 were determined in various solvents and pH values, and in the presence of chemically modified water-soluble beta-cyclodextrins. The stoichiometry and binding constants for complexes of the lactone form of DB-67 and its ring-opened carboxylate with sulfobutyl ether and 2-hydroxypropyl substituted beta-cyclodextrins (SBE-CD and HP-CD) were obtained by solubility and circular dichroism spectroscopy, respectively. Kinetics for the reversible ring-opening of DB-67 in aqueous solution and for lactone precipitation were determined by HPLC with UV detection. Solubilities of DB-67 lactone in various injectable solvent systems were found to be at least one order of magnitude below the target concentration (2 mg/ml). DB-67 forms inclusion complexes with SBE-CD and HP-CD but the solubilization attainable is substantially less than the target concentration. Slow addition of DB-67/ DMSO into 22.2% (w/v) SBE-CD failed to yield stable supersaturated solutions due to precipitation. Stable supersatured solutions were obtained, however, by mixing a concentrated alkaline aqueous solution of DB-67 carboxylate with an acidified 22.2% (w/v) SBE-CD solution. Ring-closure yielded supersaturated solutions that could be lyophilized and reconstituted to clear, stable, supersaturated solutions. The method developed provides an alternative to colloidal dispersions (e.g., liposomal suspensions, emulsions, etc.) for parenteral administration of lipophilic camptothecin analogs.

Fogging formulations for fixation of particulate contamination in ductwork and enclosures

DOEpatents

Maresca, Jr., Joseph W.; Kostelnik, Lori M.; Kriskivich, James R.; Demmer, Rick L.; Tripp, Julia L.

2015-09-08

A method and an apparatus using aqueous fixatives for fogging of ventilation ductwork, enclosures, or buildings containing dust, lint, and particulates that may be contaminated by radionuclides and other dangerous or unsafe particulate contaminants, which method and apparatus are capable of (1) obtaining full coverage within the ductwork and (2) penetrating and fixing the lint, dust and large particles present in the ductwork so that no airborne particles are released during or after the application of the fixative. New aqueous fogging solutions outperform conventional glycerin-based solutions. These aqueous solutions will fog using conventional methods of application and contain a surfactant to aid wetting and penetration of the lint and dust, a binder to stabilize loose or respirable particles, and an agent to aid in fogging and enhance adhesiveness. The solutions are safe and easy to use.

Removal of fluoride ions from drinking water and fluoride solutions by aluminum modified iron oxides in a column system.

PubMed

García-Sánchez, J J; Solache-Ríos, M; Martínez-Miranda, V; Solís Morelos, C

2013-10-01

The purpose of this work was to evaluate the potential of aluminum modified iron oxides, in a continuous flow for removal of fluoride ions from aqueous solutions and drinking water. The breakthrough curves obtained for fluoride ions adsorption from aqueous solutions and drinking water were fitted to Thomas, Bohart-Adams, and bed depth service time model (BDST). Adsorption capacities at the breakthroughs, Thomas model constant, kinetic constant and the saturation concentration were determined. The results show that in general, the adsorption efficiency decreases as the bed depth increases, and this behavior shows that the adsorption is controlled by the mass transport resistance. The adsorption capacity for fluoride ions by CP-Al is higher for fluoride aqueous solutions than drinking water. Copyright © 2013 Elsevier Inc. All rights reserved.

The influence of growth environment on the crystallization of nortriptyline hydrochloride, a tricyclic antidepressant

NASA Astrophysics Data System (ADS)

MacCalman, M. L.; Roberts, K. J.; Hendriksen, B. A.

1993-03-01

The preparation of the nortriptyline hydrochloride, an important pharmaceutical product, by crystallization from both alcohol and aqueous solutions is presented. At low temperatures this material shows a higher solubility in absolute alcohol compared to aqueous solutions in a trend which reverses at higher temperatures. Examination of crystals prepared from alcohol solutions reveal essentially a needle-like crystal habit which is in excellent agreement with morphological predictions based on the bulk crystallographic structure. In contrast crystals prepared from aqueous solution at high temperatures reveal a particulate structure dominated by heavily agglomerated crystallites with plate-like morphology. When this material is crystallized at the lower temperatures, where the solubility curve is steep, X-ray and thermal analysis appear to show that crystallization results in a new polymorphic structure associated with a less agglomerated product.

SnS2 Thin Film Deposition by Spray Pyrolysis

NASA Astrophysics Data System (ADS)

Jaber, Abdallah Yahia; Alamri, Saleh Noaiman; Aida, Mohammed Salah

2012-06-01

Tin disulfide (SnS2) thin films have been synthesized using a simplified spray pyrolysis technique using a perfume atomizer. The films were deposited using two different solutions prepared by the dilution of SnCl2 and thiourea in distilled water and in methanol. The obtained films have a microcrystalline structure. The film deposited using methanol as the solvent is nearly stochiometric SnS2 with a spinel phase having a (001) preferential orientation. The film prepared with an aqueous solution is Sn-rich. Scanning electronic microscopy (SEM) images reveal that the film deposited with the aqueous solution is rough and is formed with large wires. However, the film deposited with methanol is dense and smooth. Conductivity measurements indicate that the aqueous solution leads to an n-type semiconductor, while methanol leads to a p-type semiconductor.

Highly effective removal of basic fuchsin from aqueous solutions by anionic polyacrylamide/graphene oxide aerogels.

PubMed

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

2015-09-01

Novel anionic polyacrylamide/graphene oxide aerogels were prepared by a freeze drying method and used to remove basic fuchsin from aqueous solutions. These aerogels were sponge-like solid with lightweight, fluffy and porous structure. The batch adsorption experiments were carried out to study the effect of various parameters, such as the solution pH, adsorbent dose, contact time and temperature on adsorption properties of basic fuchsin onto anionic polyacrylamide/graphene oxide aerogels. The kinetics of adsorption corresponded to the pseudo-second-order kinetic model. The Langmuir adsorption isotherm was suitable to describe the equilibrium adsorption process. The maximum adsorption capacity was up to 1034.3 mg/g, which indicated that anionic polyacrylamide/graphene oxide aerogels were promising adsorbents for removing dyes pollutants from aqueous solution. Copyright © 2015 Elsevier Inc. All rights reserved.

Ultrafast excited-state deactivation of 9-methylhypoxanthine in aqueous solution: A QM/MM MD study.

PubMed

Guo, Xugeng; Yuan, Huijuan; An, Beibei; Zhu, Qiuling; Zhang, Jinglai

2016-04-21

Photoinduced ultrafast non-adiabatic decay of 9-methylhypoxanthine (9MHPX) in aqueous solution was investigated by ab initio surface-hopping dynamics calculations using a combined quantum mechanical/molecular mechanical approach. The absorption spectra of 9MHPX in aqueous solution were also explored by the hybrid cluster-continuum model at the level of time-dependent density functional theory along with the polarizable continuum model (PCM). The static electronic-structure calculations indicate that the absorption spectra of 9MHPX simulated by TD-B3LYP/PCM and TD-X3LYP/PCM can reproduce very well the experimental findings, with the accuracy of about 0.20 eV. According to dynamics simulations, irradiation of 9MHPX populates the bright excited singlet S1 state, which may undergo an ultrafast non-radiative deactivation to the S0 state. The lifetime of the S1 state of 9MHPX in aqueous solution is predicted to be 115.6 fs, slightly longer than that in the gas phase (88.8 fs), suggesting that the solventwater has no significant influence on the excited-state lifetime of 9MHPX. Such a behavior in 9MHPX is distinctly different from its parent hypoxanthine keto-N9H tautomer in which the excited-state lifetime of the latter in watersolution was remarkably enhanced as compared to the gas phase. The significant difference of the photodynamical behaviors between 9MHPX and keto-N9H can be ascribed to their different hydrogen bond environment in aqueous solution.

Structural properties of aqueous metoprolol succinate solutions. Density, viscosity, and refractive index at 311 K

NASA Astrophysics Data System (ADS)

Deosarkar, S. D.; Kalyankar, T. M.

2013-06-01

Density, viscosity and refractive index of aqueous solutions of metoprolol succinate of different concentrations (0.005-0.05 mol dm-3) were measured at 38°C. Apparent molar volume of resultant solutions were calculated and fitted to the Masson's equation and apparent molar volume at infinite dilution was determined graphically. Viscosity data of solutions has been fitted to the Jone-Dole equation and viscosity A- and B-coefficients were determined graphically. Physicochemical data obtained were discussed in terms of molecular interactions.

Effect of Urea on the Thermodynamics of Hexadecyltrimethylammonium Bromide Micelle Formation in Aqueous Solutions

NASA Astrophysics Data System (ADS)

Velikov, A. A.

2018-02-01

The effect of urea on the thermodynamics of hexadecyltrimethylammonium bromide (CTAB) micelle formation in aqueous urea solutions was studied by isothermal titration microcalorimetry. The thermodynamic functions of Δ H, Δ G, and Δ S of CTAB micelle formation were calculated. The critical micelle concentrations (CMC) were determined. The addition of urea to the solution decreased the micelle formation entropy. This was attributed to the "lowering" of the structural temperature of the solution, which led to an increased number of hydrogen bonds and structure formation of water.

Process for measuring low cadmium levels in blood and other biological specimens

DOEpatents

Peterson, David P.; Huff, Edmund A.; Bhattacharyya, Maryka H.

1994-01-01

A process for measuring low levels of cadmium in blood and other biological specimens is provided without interference from high levels of alkali metal contaminants by forming an aqueous solution and without contamination by environmental cadmium absent the proteins from the specimen, selectively removing cadmium from the aqueous solution on an anion exchange resin, thereby removing the alkali metal contaminants, resolubilizing cadmium from the resin to form a second solution and analyzing the second solution for cadmium, the process being carried out in a cadmium-free environment.

WET FLUORIDE SEPARATION METHOD

DOEpatents

Seaborg, G.T.; Gofman, J.W.; Stoughton, R.W.

1958-11-25

The separation of U/sup 233/ from thorium, protactinium, and fission products present in neutron-irradiated thorium is accomplished by dissolving the irradiated materials in aqueous nitric acid, adding either a soluble fluoride, iodate, phosphate, or oxalate to precipltate the thorium, separating the precipltate from the solution, and then precipitating uranlum and protactinium by alkalizing the solution. The uranium and protactinium precipitate is removcd from the solution and dissolved in nitric acid. The uranyl nitrate may then be extracted from the acid solution by means of ether, and the protactinium recovered from the aqueous phase.

Process for measuring low cadmium levels in blood and other biological specimens

DOEpatents

Peterson, David P.; Huff, Edmund A.; Bhattacharyya, Maryka H.

1994-05-03

A process for measuring low levels of cadmium in blood and other biological specimens is provided without interference from high levels of alkali metal contaminants by forming an aqueous solution and without contamination by environmental cadmium absent the proteins from the specimen, selectively removing cadmium from the aqueous solution on an anion exchange resin, thereby removing the alkali metal contaminants, resolubilizing cadmium from the resin to form a second solution and analyzing the second solution for cadmium, the process being carried out in a cadmium-free environment.

Sporostatic and sporocidal properties of aqueous formaldehyde.

NASA Technical Reports Server (NTRS)

Trujillo, R.; David, T. J.

1972-01-01

Aqueous formaldehyde is shown to exert both sporostatic and sporocidal effects on Bacillus subtilis spores. The sporostatic effect is a result of the reversible inhibition of spore germination occasioned by aqueous formaldehyde; the sporocidal effect is due to the temperature-dependent inactivation of these spores in aqueous formaldehyde. The physicochemical state of formaldehyde in solution provides a framework with which to interpret both the sporostatic and sporocidal properties of aqueous formaldehyde.

Crystal structure and solution species of Ce(III) and Ce(IV) formates: from mononuclear to hexanuclear complexes.

PubMed

Hennig, Christoph; Ikeda-Ohno, Atsushi; Kraus, Werner; Weiss, Stephan; Pattison, Philip; Emerich, Hermann; Abdala, Paula M; Scheinost, Andreas C

2013-10-21

Cerium(III) and cerium(IV) both form formate complexes. However, their species in aqueous solution and the solid-state structures are surprisingly different. The species in aqueous solutions were investigated with Ce K-edge EXAFS spectroscopy. Ce(III) formate shows only mononuclear complexes, which is in agreement with the predicted mononuclear species of Ce(HCOO)(2+) and Ce(HCOO)2(+). In contrast, Ce(IV) formate forms in aqueous solution a stable hexanuclear complex of [Ce6(μ3-O)4(μ3-OH)4(HCOO)x(NO3)y](12-x-y). The structural differences reflect the different influence of hydrolysis, which is weak for Ce(III) and strong for Ce(IV). Hydrolysis of Ce(IV) ions causes initial polymerization while complexation through HCOO(-) results in 12 chelate rings stabilizing the hexanuclear Ce(IV) complex. Crystals were grown from the above-mentioned solutions. Two crystal structures of Ce(IV) formate were determined. Both form a hexanuclear complex with a [Ce6(μ3-O)4(μ3-OH)4](12+) core in aqueous HNO3/HCOOH solution. The pH titration with NaOH resulted in a structure with the composition [Ce6(μ3-O)4(μ3-OH)4(HCOO)10(NO3)2(H2O)3]·(H2O)9.5, while the pH adjustment with NH3 resulted in [Ce6(μ3-O)4(μ3-OH)4(HCOO)10(NO3)4]·(NO3)3(NH4)5(H2O)5. Furthermore, the crystal structure of Ce(III) formate, Ce(HCOO)3, was determined. The coordination polyhedron is a tricapped trigonal prism which is formed exclusively by nine HCOO(-) ligands. The hexanuclear Ce(IV) formate species from aqueous solution is widely preserved in the crystal structure, whereas the mononuclear solution species of Ce(III) formate undergoes a polymerization during the crystallization process.

PROCESS FOR DECONTAMINATING THORIUM AND URANIUM WITH RESPECT TO RUTHENIUM

DOEpatents

Meservey, A.A.; Rainey, R.H.

1959-10-20

The control of ruthenium extraction in solvent-extraction processing of neutron-irradiated thorium is presented. Ruthenium is rendered organic-insoluble by the provision of sulfite or bisulfite ions in the aqueous feed solution. As a result the ruthenium remains in the aqueous phase along with other fission product and protactinium values, thorium and uranium values being extracted into the organic phase. This process is particularly applicable to the use of a nitrate-ion-deficient aqueous feed solution and to the use of tributyl phosphate as the organic extractant.

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

DOEpatents

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

1999-01-01

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

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

DOEpatents

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

1999-03-30

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

The dissolution of quartz in dilute aqueous solutions of organic acids at 25°C

USGS Publications Warehouse

Bennett, P.C.; Melcer, M.E.; Siegel, D.I.; Hassett, J.P.

1988-01-01

The dissolution of quartz in dilute aqueous solutions of organic acids at 25° and standard pressure was investigated by the batch dissolution method. The bulk dissolution rate of quartz in 20 mmole/Kg citrate solutions at pH 7 was 8 to 10 times faster than that in pure water. After 1750 hours the concentration of dissolved silica in the citrate solution was 167 μmole/Kg compared to 50 μmole/Kg in water and a 20 mmole/Kg solution of acetate at pH 7. Solutions of salicylic, oxalic, and humic acids also accelerated the dissolution of quartz in aqueous solution at pH 7. The rate of dissolution in organic acids decreased sharply with decreasing pH.The possibility of a silica-organic acid complex was investigated using UV-difference spectroscopy. Results suggest that dissolved silica is complexed by citrate, oxalate and pyruvate at pH 7 by an electron-donor acceptor complex, whereas no complexation occurs between silica and acetate, lactate, malonate, or succinate. Three models are proposed for the solution and surface complexation of silica by organic acid anions which result in the accelerated dissolution and increased solubility of quartz in organic rich water.

H2 Production Under Visible Light Irradiation from Aqueous Methanol Solution on CaTiO3:Cu Prepared by Spray Pyrolysis

NASA Astrophysics Data System (ADS)

Lim, Sung Nam; Song, Shin Ae; Jeong, Yong-Cheol; Kang, Hyun Woo; Park, Seung Bin; Kim, Ki Young

2017-10-01

Perovskite-type photocatalysts of CaCu x Ti1- x O3 (0 ≤ x ≤ 0.02) powder were prepared by spray pyrolysis of aqueous solution or aqueous solution with polymeric additive. The effects of the amount of copper ions doped in the photocatalyst and the precursor type on the photocatalytic activity under visible-light irradiation were investigated. The crystal structure, oxidation state, and light adsorption properties of the prepared photocatalysts were analyzed using x-ray diffraction, x-ray photoelectron spectroscopy, and diffuse reflectance spectroscopy, respectively. The doping of copper ions in CaTiO3 allowed visible-light absorption owing to a narrowing of the band gap energy of the host material through the formation of a new donor level for copper ions. Among the doped samples prepared from the aqueous precursor, CaTiO3 doped with 1 mol.% copper ions had the highest hydrogen evolution rate (140.7 μmol g-1 h-1). Notably, the hydrogen evolution rate of the photocatalyst doped with 1 mol.% copper ions prepared from the aqueous precursor with polymeric additive (295.0 μmol g-1 h-1) was two times greater than that prepared from the aqueous precursor, due to the morphology effect.

Study of a Novel Method for the Thermolysis of Solutes in Aqueous Solution Using a Low Temperature Bubble Column Evaporator.

PubMed

Shahid, Muhammad; Xue, Xinkai; Fan, Chao; Ninham, Barry W; Pashley, Richard M

2015-06-25

An enhanced thermal decomposition of chemical compounds in aqueous solution has been achieved at reduced solution temperatures. The technique exploits hitherto unrecognized properties of a bubble column evaporator (BCE). It offers better heat transfer efficiency than conventional heat transfer equipment. This is obtained via a continuous flow of hot, dry air bubbles of optimal (1-3 mm) size. Optimal bubble size is maintained by using the bubble coalescence inhibition property of some salts. This novel method is illustrated by a study of thermal decomposition of ammonium bicarbonate (NH4HCO3) and potassium persulfate (K2S2O8) in aqueous solutions. The decomposition occurs at significantly lower temperatures than those needed in bulk solution. The process appears to work via the continuous production of hot (e.g., 150 °C) dry air bubbles, which do not heat the solution significantly but produce a transient hot surface layer around each rising bubble. This causes the thermal decomposition of the solute. The decomposition occurs due to the effective collision of the solute with the surface of the hot bubbles. The new process could, for example, be applied to the regeneration of the ammonium bicarbonate draw solution used in forward osmosis.

Responsive Copolymers for Enhanced Petroleum Recovery

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

McCormick, C.; Hester, R.

The objectives of this work was to: synthesize responsive copolymer systems; characterize molecular structure and solution behavior; measure rheological properties of aqueous fluids in fixed geometry flow profiles; and to tailor final polymer compositions for in situ rheology control under simulated conditions. This report focuses on the synthesis and characterization of novel stimuli responsive copolymers, the investigation of dilute polymer solutions in extensional flow and the design of a rheometer capable of measuring very dilute aqueous polymer solutions at low torque.

The Evaporation and Degradation of N-Nitroso Dimethyl Amine in Aqueous Solutions.

DTIC Science & Technology

The fate of N-Nitroso Dimethyl Amine ( NDMA ) in aqueous solutions and in a 25 percent caustic waste stream which is produced in the manufacture of...degradation of NDMA in an open lagoon. It was found that for basic solutions, the removal was primarily evaporation, whereas, evaporation is low for...that nitrite severely inhibits the photolysis of NDMA in acid and neutral pHs, and an increase in ionic strength slightly increases the evaporation rate

Protonation-modulated localization of excess electrons in histidine aqueous solutions revealed by ab initio molecular dynamics simulations: anion-centered versus cation-centered localization.

PubMed

Gao, Liang; Bu, Yuxiang

2017-05-31

In this work, we present an ab initio molecular dynamics simulation study on the interaction of an excess electron (EE) with histidine in its aqueous solution. Two different configurations of histidine (imidazole group protonated or not) are considered to reflect its different existing forms in neutral or slightly acidic surroundings. The simulation results indicate that localizations of EEs in different aqueous histidine solutions are quite different and are strongly affected by protonation of the side chain imidazole group and are thus pH-controlled. In neutral aqueous histidine solution, an EE localizes onto the carboxyl anionic group of the amino acid backbone after a relatively lengthy diffuse state, performing just like in an aliphatic amino acid solution. But in weakly acidic solution in which the side chain imidazole group is protonated, an EE undergoes a short lifetime diffuse state and finally localizes on the protonated imidazole group. We carefully examine these two different localization dynamics processes and analyze the competition between different dominating groups in their corresponding electron localization mechanisms. To explain the difference, we investigate the frontier molecular orbitals of these two systems and find that their energy levels and compositions are important to determine these differences. These findings can provide helpful information to understand the interaction mechanisms of low energy EEs with amino acids and even oligopeptides, especially with aromatic rings.

Homogeneous and Heterogeneous (Fex, Cr1-x)(OH)3 Precipitation: Implications for Cr Sequestration

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

Dai, Chong; Zuo, Xiaobing; Cao, B

2016-02-16

The formation of (Fe, Cr)(OH)3 nanoparticles determines the fate of aqueous Cr in many aquatic environments. Using small angle X-ray scattering, precipitation rates of (Fe, Cr)(OH)3 nanoparticles in solution and on quartz were quantified from 0.1 mM Fe(III) solutions containing 0 – 0.25 mM Cr(III) at pH = 3.7 ± 0.2. Concentration ratio of aqueous Cr(III)/Fe(III) controlled the chemical composition (x) of (Fex, Cr1-x)(OH)3 precipitates, solutions’ supersaturation with respect to precipitates, and the surface charge of quartz. Therefore, aqueous Cr(III)/Fe(III) ratio affected homogeneous (in solution) and heterogeneous (on quartz) precipitation rates of (Fex, Cr1-x)(OH)3 through different mechanisms. The sequestration mechanismsmore » of Cr(III) in precipitates were also investigated. In solutions with high aqueous Cr(III)/Fe(III) ratios, surface enrichment of Cr(III) on the precipitates occurred, resulting in slower particle growth in solution. From solutions with 0 – 0.1 mM Cr(III), the particles on quartz grew from 2 to 4 nm within 1 h. Interestingly, from solution with 0.25 mM Cr(III), particles of two distinct sizes (2 and 6 nm) formed on quartz, and their sizes remained unchanged throughout the reaction. Our study provided new insights on homogeneous and heterogeneous precipitation of (Fex, Cr1-x)(OH)3 nanoparticles, which can help determine the fate of Cr in aquatic environments.« less

Thermodynamics of complexation in an aqueous solution of Tb(III) nitrate at 298 K

NASA Astrophysics Data System (ADS)

Lobacheva, O. L.; Berlinskii, I. V.; Dzhevaga, N. V.

2017-01-01

The pH of the formation of hydroxo complexes and hydrates in an aqueous solution of terbium Tb(III) is determined using combined means of potentiometric and conductometric titration. The stability constants of the hydroxo complexes, the products of hydroxide solubility, and the Gibbs energy of terbium hydroxo complex formation are calculated.

REPORT ON THE GEOELECTRICAL DETECTION OF SURFACTANT ENHANCED AQUIFER REMEDIATION OF PCE: PROPERTY CHANGES IN AQUEOUS SOLUTIONS DUE TO SURFACTANT TREATMENT OF PERCHLOROETHYLENE: IMPLICATIONS TO GEOPHYSICAL MEASUREMENTS

EPA Science Inventory

Select physicochemical properties of nine surfactants which are conventionally used in the remediation of perchloroethylene (PCE, a.k.a. tetrachloroethene) were evaluated with varying concentrations of PCE and indicator dyes in aqueous solutions using a response surface quadrati...

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

PubMed

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

2014-11-21

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

Background photobleaching in raman spectra of aqueous solutions of plant toxins

NASA Astrophysics Data System (ADS)

Brandt, Nikolai N.; Chikishev, Andrey Y.; Tonevitsky, Alexander G.

2002-05-01

Kinetics of background photobleaching in Raman spectra of aqueous solutions of ricin, ricin agglutinin and ricin binding subunit were measured. It was found that the spectrum of Raman background changes upon laser irradiation. Background intensity is lower for the samples with lower molecular weight. Photobleaching is characterized by oscillations in the multi exponentially decaying intensity.

Selective extraction of metal ions with polymeric extractants by ion exchange/redox

DOEpatents

Alexandratos, Spiro D.

1987-01-01

The specification discloses a method for the extraction of metal ions having a reduction potential of above about +0.3 from an aqueous solution. The method includes contacting the aqueous solution with a polymeric extractant having primary phosphinic acid groups, secondary phosphine oxide groups, or both phosphinic acid and phosphine oxide groups.

Salting Effects as an Illustration of the Relative Strength of Intermolecular Forces

ERIC Educational Resources Information Center

Person, Eric C.; Golden, Donnie R.; Royce, Brenda R.

2010-01-01

This quick and inexpensive demonstration of the salting of an alcohol out of an aqueous solution illustrates the impact of intermolecular forces on solubility using materials familiar to many students. Ammonium sulfate (fertilizer) is added to an aqueous 35% solution of isopropyl alcohol (rubbing alcohol and water) containing food coloring as a…

In situ chemical stimulation of diatomite formations

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

Davis, B.W.

1989-05-09

A method is described of recovering hydrocarbon from a subsurface diatomite formation comprising the steps of: a. introducing an aqueous surface solution into the diatomite formation, the aqueous surface active solution comprising (i) a diatomite/oil/ water wettability improving agent, and (ii) an oil/water interfacial tension lowering agent; and b. producing oil from the diatomite formation.

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

EPA Science Inventory

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

Form Four Students' Misconceptions in Electrolysis of Molten Compounds and Aqueous Solutions

ERIC Educational Resources Information Center

Bong, Anita Yung Li; Lee, Tien Tien

2016-01-01

The purpose of this study is to identify the Form Four students' misconceptions in the electrolysis of molten compounds and aqueous solutions. The respondents were 60 Form Four students from two secondary schools in Sibu, Sarawak. The two instruments used in this study were an open-ended electrochemistry assessment and interview protocol. This…

Importance of poly(ethylene glycol) conformation for the synthesis of silver nanoparticles in aqueous solution

USDA-ARS?s Scientific Manuscript database

In the formation of silver nanoparticles (NPs) using silver nitrate in a poly(ethylene glycol) (PEG) aqueous solution, which acts as both a reducing and stabilizing agent, the PEG chain structure was found to play a significant role. Even though PEG 100 (100 kg/mol) has limited reducing sites of hyd...

Investigations of kinetics and mechanism of chloropinnoite in boric acid aqueous solution at 303 K by Raman spectroscopy.

PubMed

Xiaoping, Li; Shiyang, Gao; Shuping, Xia

2004-10-01

Raman spectroscopy of dissolution and transformation of chloropinnoite in 4.5% (wt.%) boric acid aqueous solution at 303 K has been recorded. The Raman spectra of kinetics process have been obtained. The phase transformation product is 2MgO.3B2O3.15H2O (kurnakovite). The main polyborate anions and their interaction in aqueous solution have been proposed according to the Raman spectrum. Some assignments were tentatively given and the relations between the existing forms of polyborate anions and the crystallizing solid phases have been gained. A mechanism of dissolution and crystallization reactions and the formation condition of kurnakovite in Qinghai-Tibet plateau were proposed and discussed.

[Raman spectroscopic analysis of dissolution and phase transformation of chloropinnoite in the boric acid aqueous solution].

PubMed

Li, Xiao-Ping; Gao, Shi-Yang; Liu, Zhi-Hong; Hu, Man-Cheng; Xia, Shu-Ping

2005-01-01

Raman spectroscopy of dissolution and transformation of chloropinnoite in 4.5% (w.t.%) boric acid aqueous solution at 30 degrees C has been recorded. The Raman spectra of kinetics process have been obtained. The phase transformation product is kurnakovite (2MgO x 3B2O3 x 15H2O). The main polyborate anions and their interaction in aqueous solution have been proposed according to the Raman spectrum. Some assignments were tentatively given and the relations between the existing forms of polyborate anions and the crystallizing solid phases have been gained. A mechanisms of dissolution and crystallization reactions and the formation condition of kurnakovite in Qinghai-Tibet plateau were proposed and discussed.

Water Assisted Reaction Mechanism of OH- with CCl4 in Aqueous Solution - Hybrid Quantum Mechanical and Molecular Mechanics Investigation

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

Chen, Jie; Yin, Hongyun; Wang, Dunyou

2013-02-20

The OH- (H2O) + CCl4 reaction in aqueous solution was investigated using the combined quantum mechanical and molecular mechanics approach. The reaction mechanism of OH- (H2O) + CCl4 consists of two concerted steps - formation of OH- in the favorable attack conformation via the proton transfer process, and the nucleophilic substitution process in which the newly formed OH- attacks the CCl4. The free energy activation barrier is 38.2 kcal/mol at CCSD(T)/MM level of theory for this reaction, which is about 10.3 kcal/mol higher than that of the direct nucleophilic substitution mechanism of the OH- + CCl4 reaction in aqueous solution.

Fluidized bed gasification of extracted coal

DOEpatents

Aquino, D.C.; DaPrato, P.L.; Gouker, T.R.; Knoer, P.

1984-07-06

Coal or similar carbonaceous solids are extracted by contacting the solids in an extraction zone with an aqueous solution having a pH above 12.0 at a temperature between 65/sup 0/C and 110/sup 0/C for a period of time sufficient to remove bitumens from the coal into said aqueous solution, and the extracted solids are then gasified at an elevated pressure and temperature in a fluidized bed gasification zone (60) wherein the density of the fluidized bed is maintained at a value above 160 kg/m/sup 3/. In a preferred embodiment of the invention, water is removed from the aqueous solution in order to redeposit the extracted bitumens onto the solids prior to the gasification step. 2 figs., 1 tab.

A lithium ion battery using an aqueous electrolyte solution

PubMed Central

Chang, Zheng; Li, Chunyang; Wang, Yanfang; Chen, Bingwei; Fu, Lijun; Zhu, Yusong; Zhang, Lixin; Wu, Yuping; Huang, Wei

2016-01-01

Energy and environmental pollution have become the two major problems in today’s society. The development of green energy storage devices with good safety, high reliability, high energy density and low cost are urgently demanded. Here we report on a lithium ion battery using an aqueous electrolyte solution. It is built up by using graphite coated with gel polymer membrane and LISICON as the negative electrode, and LiFePO4 in aqueous solution as the positive electrode. Its average discharge voltage is up to 3.1 V and energy density based on the two electrode materials is 258 Wh kg−1. It will be a promising energy storage system with good safety and efficient cooling effects. PMID:27328707

Plasma induced grafting carboxymethyl cellulose on multiwalled carbon nanotubes for the removal of UO(2)(2+) from aqueous solution.

PubMed

Shao, Dadong; Jiang, Zhongqing; Wang, Xiangke; Li, Jiaxing; Meng, Yuedong

2009-01-29

Carboxymethyl cellulose (CMC) is grafted on multiwalled carbon nanotubes (MWCNT) by using plasma techniques. The CMC grafted MWCNT (MWCNT-g-CMC) is characterized by using Fourier transform infrared spectra (FT-IR), Raman spectra, powder X-ray diffraction (XRD), thermogravimetric analysis (TGA)-differential thermal analysis (DTA), scanning electron microscopy (SEM), and N(2)-BET methods in detail. The application of MWCNT-g-CMC in the removal of UO(2)(2+) from aqueous solution is investigated. MWCNT-g-CMC has much higher sorption ability in the removal of UO(2)(2+) than raw MWCNT. The MWCNT-g-CMC is a suitable material in the preconcentration and solidification of heavy metal ions from large volume of aqueous solutions.

Development of structure in natural silk spinning and poly(vinyl alcohol) hydrogel formation

NASA Astrophysics Data System (ADS)

Willcox, Patricia Jeanene

This research involves the characterization of structure and structure formation in aqueous systems. Particularly, these studies investigate the effect of various processing variables on the structure formation that occurs upon conversion from aqueous solution to fiber or hydrogel. The two processes studied include natural silk fiber spinning and physical gelation of poly(vinyl alcohol), PVOH, in water. The techniques employed combine cryogenic technology for sample preparation and direct observation by transmission electron microscopy with electron diffraction, atomic force microscopy, optical rheometry, X-ray scattering and optical microscopy. In order to explore the full range of structure formation in natural silk spinning, studies are conducted in vivo and in vitro. In vivo structural investigations are accomplished through the cryogenic quenching and subsequent microtoming of live silk-spinning animals, Nephila clavipes (spider) and Bombyx mori (silkworm). Observations made using transmission electron microscopy, electron diffraction and atomic force microscopy indicate a cholesteric liquid crystalline mesophase of aqueous silk fibroin in both species. The mechanism of structure formation in solution is studied in vitro using optical rheometry on aqueous solutions made from regenerated Bombyx mori cocoon silk. Concentrated solutions exhibit birefringence under flow, with a wormlike conformation of the silk molecules in concentrated salt solution. Changes in salt concentration and pH of the aqueous silk solutions result in differing degrees of alignment and aggregation. These results suggest that structural control in the natural silk spinning process is accomplished by chemical manipulation of the electrostatic interactions and hydrogen bonding between chains. Application of cryogenic methods in transmission electron microscopy also provides a unique look at hydration-dependent structures in gels of poly(vinyl alcohol) produced by freeze-thaw processing. Morphologies ranging from circular pores to fibrillar networks are observed in gels formed from aqueous PVOH solutions subjected to cycles of freezing and thawing. These morphologies can be directly associated with the progressive nature of the mechanism of gelation as it proceeds from liquid-liquid phase separation to crystallization with increased cycling. A comparison of the structures produced by cycling and by aging suggests that there is a similarity in structural changes, but a superposition of the effects of cycling and aging is not possible.

Phytodegradation potential of bisphenolA from aqueous solution by Azolla Filiculoides

PubMed Central

2014-01-01

Many organic hazardous pollutants such as bisphenolA (BPA) which are toxic and not easily biodegradable can concerns for environmental pollution worldwide. The objective of this study was to examine whether Azolla Filiculoides is able to remove BPA from aqueous solutions. In this study, the Azolla with different biomass (0.3, 0.6, 0.9, 1.2 g) has been cultured in solution that was contained 5, 10, 25 and 50 ppm BPA. Samples were collected every 2 days from all of containers. The analytical determination of BPA was performed by using of DR4000 uv-visible at λmax = 276 nm. The results indicated that Azolla has high ability to remove BPA from aqueous solutions. The BPA removal was 60-90%. The removal efficiency is increasing with decreasing of BPA concentration and increasing of biomass amount and vice versa. The removal efficiency was more than 90% when BPA concentration was 5 ppm and amount of biomass was 0.9gr. It is concluded that Azolla able remove BPA by Phytodegradation from the aqueous solutions. Since conventional methods of BPA removal need to high cost and energy, phytoremediation by Azolla as a natural treatment system can decrease those issues and it can be a useful and beneficial method to removal of BPA. PMID:24693863

Phytodegradation potential of bisphenolA from aqueous solution by Azolla Filiculoides.

PubMed

Zazouli, Mohammad Ali; Mahdavi, Yousef; Bazrafshan, Edris; Balarak, Davoud

2014-01-01

Many organic hazardous pollutants such as bisphenolA (BPA) which are toxic and not easily biodegradable can concerns for environmental pollution worldwide. The objective of this study was to examine whether Azolla Filiculoides is able to remove BPA from aqueous solutions. In this study, the Azolla with different biomass (0.3, 0.6, 0.9, 1.2 g) has been cultured in solution that was contained 5, 10, 25 and 50 ppm BPA. Samples were collected every 2 days from all of containers. The analytical determination of BPA was performed by using of DR4000 uv-visible at λmax = 276 nm. The results indicated that Azolla has high ability to remove BPA from aqueous solutions. The BPA removal was 60-90%. The removal efficiency is increasing with decreasing of BPA concentration and increasing of biomass amount and vice versa. The removal efficiency was more than 90% when BPA concentration was 5 ppm and amount of biomass was 0.9gr. It is concluded that Azolla able remove BPA by Phytodegradation from the aqueous solutions. Since conventional methods of BPA removal need to high cost and energy, phytoremediation by Azolla as a natural treatment system can decrease those issues and it can be a useful and beneficial method to removal of BPA.

Degradation of alachlor in aqueous solution by using hydrodynamic cavitation.

PubMed

Wang, Xikui; Zhang, Yong

2009-01-15

The degradation of alachlor aqueous solution by using hydrodynamic cavitation was systematically investigated. It was found that alachlor in aqueous solution can be deomposed with swirling jet-induced cavitation. The degradation can be described by a pseudo-first-order kinetics and the degradation rate was found to be 4.90x10(-2)min(-1). The effects of operating parameters such as fluid pressure, solution temperature, initial concentration of alachlor and medium pH on the degradation rates of alachlor were also discussed. The results showed that the degradation rates of alachlor increased with increasing pressure and decreased with increasing initial concentration. An optimum temperature of 40 degrees C existed for the degradation rate of alachlor and the degradation rate was also found to be slightly depend on medium pH. Many degradation products formed during the process, and some of them were qualitatively identified by GC-MS.

The IR Absorption Spectra of Aqueous Solutions of Dimethylsulfoxide over the Frequency Range 50-300 cm-1 and the Mobility of Water Molecules

NASA Astrophysics Data System (ADS)

Klemenkova, Z. S.; Novskova, T. A.; Lyashchenko, A. K.

2008-04-01

The IR absorption spectra of aqueous solutions of dimethylsulfoxide (DMSO) with concentrations from 100% H2O to 100% DMSO were recorded over the frequency range 50-500 cm-1. The absorption spectra were described using the theoretical scheme of hindered rotators. A model was developed according to which orientation relaxation in solution was related to separate rotations of H2O and DMSO molecules through fixed small and (or) large angles in a unified network of H-bonds consisting of several subsystems ordered to various degrees. The calculated absorption spectra were in agreement with the experimental data in the far IR region. Elementary motions of molecules were found to slow down in the passage from pure dimethylsulfoxide to its aqueous solutions. The special features of the hydrophilic and hydrophobic hydration of DMSO polar and nonpolar groups were considered.

Fragmentation-based QM/MM simulations: length dependence of chain dynamics and hydrogen bonding of polyethylene oxide and polyethylene in aqueous solutions.

PubMed

Li, Hui; Li, Wei; Li, Shuhua; Ma, Jing

2008-06-12

Molecular fragmentation quantum mechanics (QM) calculations have been combined with molecular mechanics (MM) to construct the fragmentation QM/MM method for simulations of dilute solutions of macromolecules. We adopt the electrostatics embedding QM/MM model, where the low-cost generalized energy-based fragmentation calculations are employed for the QM part. Conformation energy calculations, geometry optimizations, and Born-Oppenheimer molecular dynamics simulations of poly(ethylene oxide), PEO(n) (n = 6-20), and polyethylene, PE(n) ( n = 9-30), in aqueous solution have been performed within the framework of both fragmentation and conventional QM/MM methods. The intermolecular hydrogen bonding and chain configurations obtained from the fragmentation QM/MM simulations are consistent with the conventional QM/MM method. The length dependence of chain conformations and dynamics of PEO and PE oligomers in aqueous solutions is also investigated through the fragmentation QM/MM molecular dynamics simulations.

Energetics of the molecular interactions of L-cysteine, L-serine, and L-asparagine in aqueous propylene glycol solutions at 298.15 K

NASA Astrophysics Data System (ADS)

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

2015-03-01

Integral enthalpies of dissolution Δsol H m of L-cysteine, L-serine, and L-asparagine in aqueous solutions of 1,3-propylene glycol at organic solvent concentrations of up to 0.26 mole fraction are measured via the thermochemistry of dissolution. Standard enthalpies of dissolution (Δsol H ○) and transfer (Δtr H ○) of amino acids from water to a mixed solvent are calculated. It is found that the calculated enthalpy coefficients of pair interactions of the amino acids with polyhydric alcohol molecules have positive values. The effect the arrangement of the hydroxyl group in the structure of polyhydric alcohols has on the enthalpy of interaction of amino acids in aqueous solutions is revealed. The effect of different types of interactions in solutions and the structural features of biomolecules and cosolvents on the enthalpy of dissolution of amino acids is analyzed.

Recrystallization of freezable bound water in aqueous solutions of medium concentration

NASA Astrophysics Data System (ADS)

Lishan, Zhao; Liqing, Pan; Ailing, Ji; Zexian, Cao; Qiang, Wang

2016-07-01

For aqueous solutions with freezable bound water, vitrification and recrystallization are mingled, which brings difficulty to application and misleads the interpretation of relevant experiments. Here, we report a quantification scheme for the freezable bound water based on the water-content dependence of glass transition temperature, by which also the concentration range for the solutions that may undergo recrystallization finds a clear definition. Furthermore, we find that depending on the amount of the freezable bound water, different temperature protocols should be devised to achieve a complete recrystallization. Our results may be helpful for understanding the dynamics of supercooled aqueous solutions and for improving their manipulation in various industries. Project supported by the Knowledge Innovation Project of Chinese Academy of Sciences on Water Science Research (Grant No. KJZD-EW-M03) and the National Natural Science Foundation of China (Grant Nos. 11474325 and 11290161).

Ultrasound degradation of xanthan polymer in aqueous solution: Its scission mechanism and the effect of NaCl incorporation.

PubMed

Saleh, H M; Annuar, M S M; Simarani, K

2017-11-01

Degradation of xanthan polymer in aqueous solution by ultrasonic irradiation was investigated. The effects of selected variables i.e. sonication intensity, irradiation time, concentration of xanthan gum and molar concentration of NaCl in solution were studied. Combined approach of full factorial design and conventional one-factor-at-a-time was applied to obtain optimum degradation at sonication power intensity of 11.5Wcm -2 , irradiation time 120min and 0.1gL -1 xanthan in a salt-free solution. Molecular weight reduction of xanthan gum under sonication was described by an exponential decay function with higher rate constant for polymer degradation in the salt free solution. The limiting molecular weight where fragments no longer undergo scission was determined from the function. The incorporation of NaCl in xanthan solution resulted in a lower limiting molecular weight. The ultrasound-mediated degradation of aqueous xanthan polymer chain agreed with a random scission model. Side chain of xanthan polymer is proposed to be the primary site of scission action. Copyright © 2017 Elsevier B.V. All rights reserved.

Closantel nano-encapsulated polyvinyl alcohol (PVA) solutions.

PubMed

Vega, Abraham Faustino; Medina-Torres, Luis; Calderas, Fausto; Gracia-Mora, Jesus; Bernad-Bernad, MaJosefa

2016-08-01

The influence of closantel on the rheological and physicochemical properties (particle size and by UV-Vis absorption spectroscopy) of PVA aqueous solutions is studied here. About 1% PVA aqueous solutions were prepared by varying the closantel content. The increase of closantel content led to a reduction in the particle size of final solutions. All the solutions were buffered at pH 7.4 and exhibited shear-thinning behavior. Furthermore, in oscillatory flow, a "solid-like" type behavior was observed for the sample containing 30 μg/mL closantel. Indicating a strong interaction between the dispersed and continuous phases and evidencing an interconnected network between the nanoparticle and PVA, this sample also showed the highest shear viscosity and higher shear thinning slope, indicating a more intrincate structure disrupted by shear. In conclusion, PVA interacts with closantel in aqueous solution and the critical concentration for closantel encapsulation by PVA was about 30 μg/mL; above this concentration, the average particle size decreased notoriously which was associated to closantel interacting with the surface of the PVA aggregates and thus avoiding to some extent direct polymer-polymer interaction.

Assessment of the leaching of metallic elements in the technology of solidification in aqueous solution.

PubMed

Rossetti, V Alunno; Di Palma, L; Medici, F

2002-01-01

Results are presented of experiments performed to optimize the solidification/stabilization system for metallic elements in aqueous solution. This system involves mixing cement and a solution of metallic elements in a conventional mixer: the paste thus obtained is transferred drop by drop into a recipient filled with an aqueous solution of NaOH at 20% by weight, in which it solidifies immediately. The separate use of chloride solutions of Li+, Cr3+, Pb2+ and Zn2+ makes it possible to obtain granules displaying various levels of compressive strength. Three different inertization matrices were used in the experiments, the first consisting solely of Portland cement, the second of Portland cement and a superplasticizer additive, and the third of Portland cement partially replaced with silica-fume and superplasticizer. The results of the tests performed showed a very low level of leaching into the alkaline solidification solution for Cr3+, the quantity leached being under 2% as against higher levels for the other metallic elements. For all the considered elements, the best results were obtained by using silica-fume in the inertization matrix.

Multiple pathways of crystal nucleation in an extremely supersaturated aqueous potassium dihydrogen phosphate (KDP) solution droplet

PubMed Central

Lee, Sooheyong; Wi, Haeng Sub; Jo, Wonhyuk; Cho, Yong Chan; Lee, Hyun Hwi; Jeong, Se-Young; Kim, Yong-Il; Lee, Geun Woo

2016-01-01

Solution studies have proposed that crystal nucleation can take more complex pathways than previously expected in classical nucleation theory, such as formation of prenucleation clusters or densified amorphous/liquid phases. These findings show that it is possible to separate fluctuations in the different order parameters governing crystal nucleation, that is, density and structure. However, a direct observation of the multipathways from aqueous solutions remains a great challenge because heterogeneous nucleation sites, such as container walls, can prevent these paths. Here, we demonstrate the existence of multiple pathways of nucleation in highly supersaturated aqueous KH2PO4 (KDP) solution using the combination of a containerless device (electrostatic levitation), and in situ micro-Raman and synchrotron X-ray scattering. Specifically, we find that, at an unprecedentedly deep level of supersaturation, a high-concentration KDP solution first transforms into a metastable crystal before reaching stability at room temperature. However, a low-concentration solution, with different local structures, directly transforms into the stable crystal phase. These apparent multiple pathways of crystallization depend on the degree of supersaturation. PMID:27791068

Multiple pathways of crystal nucleation in an extremely supersaturated aqueous potassium dihydrogen phosphate (KDP) solution droplet.

PubMed

Lee, Sooheyong; Wi, Haeng Sub; Jo, Wonhyuk; Cho, Yong Chan; Lee, Hyun Hwi; Jeong, Se-Young; Kim, Yong-Il; Lee, Geun Woo

2016-11-29

Solution studies have proposed that crystal nucleation can take more complex pathways than previously expected in classical nucleation theory, such as formation of prenucleation clusters or densified amorphous/liquid phases. These findings show that it is possible to separate fluctuations in the different order parameters governing crystal nucleation, that is, density and structure. However, a direct observation of the multipathways from aqueous solutions remains a great challenge because heterogeneous nucleation sites, such as container walls, can prevent these paths. Here, we demonstrate the existence of multiple pathways of nucleation in highly supersaturated aqueous KH 2 PO 4 (KDP) solution using the combination of a containerless device (electrostatic levitation), and in situ micro-Raman and synchrotron X-ray scattering. Specifically, we find that, at an unprecedentedly deep level of supersaturation, a high-concentration KDP solution first transforms into a metastable crystal before reaching stability at room temperature. However, a low-concentration solution, with different local structures, directly transforms into the stable crystal phase. These apparent multiple pathways of crystallization depend on the degree of supersaturation.

Theoretical study of the influence of chemical reactions and physical parameters on the convective dissolution of CO2 in aqueous solutions

NASA Astrophysics Data System (ADS)

Loodts, Vanessa; Rongy, Laurence; De Wit, Anne

2014-05-01

Subsurface carbon sequestration has emerged as a promising solution to the problem of increasing atmospheric carbon dioxide (CO2) levels. How does the efficiency of such a sequestration process depend on the physical and chemical characteristics of the storage site? This question is emblematic of the need to better understand the dynamics of CO2 in subsurface formations, and in particular, the properties of the convective dissolution of CO2 in the salt water of aquifers. This dissolution is known to improve the safety of the sequestration by reducing the risks of leaks of CO2 to the atmosphere. Buoyancy-driven convection makes this dissolution faster by transporting dissolved CO2 further away from the interface. Indeed, upon injection, the less dense CO2 phase rises above the aqueous layer where it starts to dissolve. The dissolved CO2 increases the density of the aqueous solution, thereby creating a layer of denser CO2-rich solution above less dense solution. This unstable density gradient in the gravity field is at the origin of convection. In this framework, we theoretically investigate the effect of CO2 pressure, salt concentration, temperature, and chemical reactions on the dissolution-driven convection of CO2 in aqueous solutions. On the basis of a linear stability analysis, we assess the stability of the time-dependent density profiles developing when CO2 dissolves in an aqueous layer below it. We predict that increasing CO2 pressure destabilizes the system with regard to buoyancy-driven convection, because it increases the density gradient at the origin of the instability. By contrast, increasing salt concentration or temperature stabilizes the system via effects on CO2 solubility, solutal expansion coefficient, diffusion coefficient and on the viscosity and density of the solution. We also show that a reaction of CO2 with chemical species dissolved in the aqueous solution can either enhance or decrease the amplitude of the convective dissolution compared to the non reactive one. On the basis of a reaction-diffusion-convection model, we classify the various possible cases and show that the difference between the solutal expansion coefficients of the reactant and of the product governs the type of density profile building up in the aqueous solution and thus the stability of the system. By contrast to non reactive density profiles, reactive density profiles can feature a minimum that induces a delay of the buoyancy-driven convection. This work identifies the parameters that could influence the dissolution-driven convection in the aquifers, and thus impact the safety of the sequestration. In other words, this theoretical study shows that it is crucial to analyse the composition and reactivity of potential storage sites to choose those that will be most efficient for long-term CO2 sequestration.

Standard state thermodynamic properties of completely ionized aqueous sodium sulfate using high dilution calorimetry up to 598.15 K.

PubMed

Djamali, Essmaiil; Chen, Keith; Cobble, James W

2009-08-27

Pabalan and Pitzer (Geochim. Cosmochim. Acta 1988, 52, 2393-2404) reported a comprehensive set of thermodynamic properties of aqueous solutions of sodium sulfate without using ion association or hydrolysis. However, there is now ample evidence available indicating that the ion association cannot be ignored at temperatures T>or=373 K. For example, even at the lowest concentration of their studies (m>or=0.05) and at 573.15 K, less than 20% of SO4(2-)(aq) is available as free ions. In the present study, the integral heats of solution of sodium sulfate were measured to very low concentrations (10(-4) m) up to 573.16 K. The data were analyzed correcting for the hydrolysis of SO4(2-)(aq) and the association of Na+(aq) with SO4(2-)(aq) and NaSO4-(aq) in order to obtain the final standard state thermodynamic properties of completely ionized aqueous sodium sulfate, Na2SO4(aq). From these and the available solubility data, the stoichiometric activity coefficients of saturated aqueous solutions of sodium sulfate were calculated up to 573.15 K and compared with literature data. The stoichiometric activity coefficients of aqueous solutions of sodium sulfate, as a function of temperature at all concentrations (0

Assessment and correction of turbidity effects on Raman observations of chemicals in aqueous solutions.

PubMed

Sinfield, Joseph V; Monwuba, Chike K

2014-01-01

Improvements in diode laser, fiber optic, and data acquisition technologies are enabling increased use of Raman spectroscopic techniques for both in lab and in situ water analysis. Aqueous media encountered in the natural environment often contain suspended solids that can interfere with spectroscopic measurements, yet removal of these solids, for example, via filtration, can have even greater adverse effects on the extent to which subsequent measurements are representative of actual field conditions. In this context, this study focuses on evaluation of turbidity effects on Raman spectroscopic measurements of two common environmental pollutants in aqueous solution: ammonium nitrate and trichloroethylene. The former is typically encountered in the runoff from agricultural operations and is a strong scatterer that has no significant influence on the Raman spectrum of water. The latter is a commonly encountered pollutant at contaminated sites associated with degreasing and cleaning operations and is a weak scatterer that has a significant influence on the Raman spectrum of water. Raman observations of each compound in aqueous solutions of varying turbidity created by doping samples with silica flour with grain sizes ranging from 1.6 to 5.0 μm were employed to develop relationships between observed Raman signal strength and turbidity level. Shared characteristics of these relationships were then employed to define generalized correction methods for the effect of turbidity on Raman observations of compounds in aqueous solution.

Removal of xylenol orange from its aqueous solution using SDS self-microemulsifying systems: optimization by Box-Behnken statistical design.

PubMed

Shakeel, Faiyaz; Haq, Nazrul; Alanazi, Fars K; Alsarra, Ibrahim A

2014-04-01

The aim of present study was to develop and evaluate sodium dodecyl sulfate (SDS) self-microemulsifying systems (SMES) for the removal of an anionic dye xylenol orange (XO) from its bulk aqueous media via liquid-liquid adsorption. The composition of SDS SMES was optimized by Box-Behnken statistical design for the maximum removal of XO from its aqueous solution. Various SDS formulations were prepared by spontaneous emulsification method and characterized for thermodynamic stability, self-microemulsification efficiency, droplet size, and viscosity. Adsorption studies were conducted at 8, 16, and 24 h by mixing small amounts of SDS formulations with relatively large amounts of bulk aqueous solution of XO. Droplet size and viscosity of SDS formulations were significantly influenced by oil phase concentration (triacetin), while surfactant concentration had little impact on droplet size and viscosity. However, the percentage of removal of XO was influenced by triacetin concentration, surfactant concentration, and adsorption time. Based on lowest droplet size (35.97 nm), lowest viscosity (29.62 cp), and highest percentage of removal efficiency (89.77 %), formulation F14, containing 2 % w/w of triacetin and 40 % w/w of surfactant mixture (20 % w/w of SDS and 20 % w/w of polyethylene glycol 400), was selected as an optimized formulation for the removal of XO from its bulk aqueous media after 16 h. These results indicated that SDS SMES could be suitable alternates of solid-liquid adsorption for the removal of toxic dyes such as XO from its aqueous solution through liquid-liquid adsorption.

The magic of aqueous solutions of ionic liquids: ionic liquids as a powerful class of catanionic hydrotropes†

PubMed Central

Cláudio, Ana Filipa M.; Neves, Márcia C.; Shimizu, Karina; Canongia Lopes, José N.; Freire, Mara G.; Coutinho, João A. P.

2015-01-01

Hydrotropes are compounds able to enhance the solubility of hydrophobic substances in aqueous media and therefore are widely used in the formulation of drugs, cleaning and personal care products. In this work, it is shown that ionic liquids are a new class of powerful catanionic hydrotropes where both the cation and the anion synergistically contribute to increase the solubility of biomolecules in water. The effects of the ionic liquid chemical structures, their concentration and the temperature on the solubility of two model biomolecules, vanillin and gallic acid were evaluated and compared with the performance of conventional hydrotropes. The solubility of these two biomolecules was studied in the entire composition range, from pure water to pure ionic liquids, and an increase in the solubility of up to 40-fold was observed, confirming the potential of ionic liquids to act as hydrotropes. Using dynamic light scattering, NMR and molecular dynamics simulations, it was possible to infer that the enhanced solubility of the biomolecule in the IL aqueous solutions is related to the formation of ionic-liquid–biomolecules aggregates. Finally, it was demonstrated that hydrotropy induced by ionic liquids can be used to recover solutes from aqueous media by precipitation, simply by using water as an anti-solvent. The results reported here have a significant impact on the understanding of the role of ionic liquid aqueous solutions in the extraction of value-added compounds from biomass as well as in the design of novel processes for their recovery from aqueous media. PMID:26379471

Water-soluble Schiff base-actinyl complexes and their effect on the solvent extraction of f-elements

DOE PAGES

Hawkins, Cory A.; Bustillos, Christian G.; May, Iain; ...

2016-09-07

Conventional solvent extraction of selected f-element cations by bis(2-ethylhexyl)phosphoric acid (HDEHP) yields increased extraction from aqueous to organic solution along the series Np(V) < Cm(III) < Eu(III) < U(VI), with distribution ratios all within two orders of magnitude. However, in the presence of the water-soluble tetradentate Schiff base (N,N'-bis(5-sulfonatosalicylidene)-ethylenediamine or H 2salenSO 3), selective complexation of the two actinyl cations (Np(V) and U(VI)) resulted in an extraction order of Np(V) < U(VI) << Eu(III) < Cm(III). The extraction of neither Cm(III) or Eu(III) by HDEHP are significantly impacted by the presence of the aqueous phase Schiff base. Despite observed hydrolyticmore » decomposition of H 2salenSO 3 in aqueous solutions, the calculated high conditional stability constant (β 11 = 26) for the complex [UO 2(salenSO 3)] 2- demonstrates its capacity for aqueous hold-back of U(VI). UV-visible-NIR spectroscopy of solutions prepared with a Np(VI) stock and H 2salenSO 3 suggest that reduction of Np(VI) to Np(V) by the ligand was rapid, resulting in a pentavalent Np complex that was substantially retained in the aqueous phase. Lastly, results from 1H NMR of aqueous solutions of H 2salenSO 3 with U(VI) and La(III), Eu(III), and Lu(III) provides additional evidence that the ligand readily chelates U(VI), but has only weak interactions with trivalent lanthanide ions.« less

Calculation of amorphous silica solubilities at 25° to 300°C and apparent cation hydration numbers in aqueous salt solutions using the concept of effective density of water

USGS Publications Warehouse

Fournier, Robert O.; Williams, Marshall L.

1983-01-01

The solubility of amorphous silica in aqueous salt solutions at 25° to 300°C can be calculated using information on its solubility in pure water and a model in which the activity of water in the salt solution is defined to equal the effective density. pe, of “free” water in that solution. At temperatures of 100°C and above, pe closely equals the product of the density of the solution times the weight fraction of water in the solution. At 25°C, a correction parameter must be applied to pe that incorporates a term called the apparent cation hydration number, h. Because of the many assumptions and other uncertainties involved in determining values of h, by the model used here, the reported numbers are not necessarily real hydration numbers even though they do agree with some published values determined by activity and diffusion methods. Whether or not h is a real hydration number, it would appear to be useful in its inclusion within a more extensive activity coefficient term that describes the departure of silica solubilities in concentrated salt solutions from expected behavior according to the model presented here. Values of h can be calculated from measured amorphous silica solubilities in salt solutions at 25°C provided there is no complexing of dissolved silica with the dissolved salt, or if the degree of complexing is known. The previously postulated aqueous silica-sulfate complexing in aqueous Na2SO4 solutions is supported by results of the present effective density of water model

Forced Spreading of Aqueous Solutions on Zwitterionic Sulfobetaine Surfaces for Rapid Evaporation and Solute Separation.

PubMed

Wu, Cyuan-Jhang; Singh, Vickramjeet; Sheng, Yu-Jane; Tsao, Heng-Kwong

2017-08-01

Solute separation of aqueous mixtures is mainly dominated by water vaporization. The evaporation rate of an aqueous drop grows with increasing the liquid-gas interfacial area. The spontaneous spreading behavior of a water droplet on a total wetting surface provides huge liquid-gas interfacial area per unit volume; however, it is halted by the self-pinning phenomenon upon addition of nonvolatile solutes. In this work, it is shown that the solute-induced self-pinning can be overcome by gravity, leading to anisotropic spreading much faster than isotropic spreading. The evaporation rate of anisotropic spreading on a zwitterionic sulfobetaine surface is 25 times larger as that on a poly(methyl methacrylate) surface. Dramatic enhancement of evaporation is demonstrated by simultaneous formation of fog atop liquid film. During anisotropic spreading, the solutes are quickly precipitated out within 30 s, showing the rapid solute-water separation. After repeated spreading process for the dye-containing solution, the mean concentration of the collection is doubled, revealing the concentration efficiency as high as 100%. Gravity-enhanced spreading on total wetting surfaces at room temperature is easy to scale-up with less energy consumption, and thus it has great potentials for the applications of solute separation and concentration.

REMOVAL OF CHLORIDE FROM AQUEOUS SOLUTIONS

DOEpatents

Hyman, M.L.; Savolainen, J.E.

1960-01-01

A method is given for dissolving reactor fuel elements in which the uranium is associated with a relatively inert chromium-containing alloy such as stainless steel. An aqueous mixture of acids comprising 2 to 2.5 molar hydrochloric acid and 4 to 8 molar nitric acid is employed in dissolving the fuel element. In order io reduce corrosion in subsequent processing of the resulting solution, chloride values are removed from the solution by contacting it with concentrated nitric acid at an elevated temperature.

Environmental Transport and Fate Process Descriptors for Propellant Compounds

DTIC Science & Technology

2006-06-01

compositional changes that occur when propellant pellets and flakes are immersed in stirred aqueous solutions for 0 to 220 hours. ERDC/EL TR-06-7 2... solution , NQ concen- tration remains constant in heated, dilute hydrochloric acid, but will hydrolyze to NH3, N2O, and CO2 at pH greater than 10...with values between 36 and 300 mg/L (Table 2). Hydrolysis of DPA was inferred from decreased Daphnia toxicity when aged (30-day) aqueous solutions

ELECTROLYTIC PRODUCTION OF URANIUM TETRAFLUORIDE

DOEpatents

Lofthouse, E.

1954-08-31

This patent relates to electrolytic methods for the production of uranium tetrafluoride. According to the present invention a process for the production of uranium tetrafluoride comprises submitting to electrolysis an aqueous solution of uranyl fluoride containing free hydrofluoric acid. Advantageously the aqueous solution of uranyl fluoride is obtained by dissolving uranium hexafluoride in water. On electrolysis, the uranyl ions are reduced to uranous tons at the cathode and immediately combine with the fluoride ions in solution to form the insoluble uranium tetrafluoride which is precipitated.

Complications in complexation kinetics for lanthanides with DTPA using dye probe molecules in aqueous solution

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

Larsson, K.; Cullen, T. D.; Mezyk, S. P.

The complexation kinetics for the polyaminopolycarboxylic ligand DTPA to lanthanides in acidic aqueous solution were investigated using the dye ligand displacement technique and stopped-flow spectroscopy. Significant rate differences were obtained for different dye probes used, indicating that the kinetics of the dissociation of the dye molecule significantly impacts the overall measured kinetics when using this common methodology. The conditions of the solution also influenced the dye-lanthanide-DTPA interactions, which reconciled previously disparate data in the literature.

SEPARATION PROCESS FOR TRANSURANIC ELEMENT AND COMPOUNDS THEREOF

DOEpatents

Calvin, M.

1958-10-14

S> A process is presented for the separation of pluto nium from uranium and fission products in an aqueous acidic solution by use of a chelating agent. The plutonium is maintained in the tetravalent state and the uranium in the hexavalent state, and the acidic concentration is adjusted to about 1 N bar. The aqueous solution is then contacted with a water-immiscible organic solvent solution and the chelating agent. The chelating agents covered by this invention comprise a group of compounds characterized as fluorinated beta-diketones.

Non-aqueous solution preparation of doped and undoped Li{sub x}Mn{sub y}O{sub z}

DOEpatents

Boyle, T.J.; Voigt, J.A.

1997-05-20

A method is described for generation of phase-pure doped and undoped Li{sub x}Mn{sub y}O{sub z} precursors. The method of this invention uses organic solutions instead of aqueous solutions or nonsolution ball milling of dry powders to produce phase-pure precursors. These precursors can be used as cathodes for lithium-polymer electrolyte batteries. Dopants may be homogeneously incorporated to alter the characteristics of the powder. 1 fig.

Solubility of NaCl and KCl in aqueous HCl from 20 to 85°C

USGS Publications Warehouse

Potter, Robert W.; Clynne, Michael A.

1980-01-01

The solubilities of NaCl and KCl in aqueous HCl solutions were determined from 20 to 85°C at concentrations ranging from 0 to 20 g of HCl/100 g of solution. Equations are given that describe the solubilities over the range of conditions studied. For NaCl and KCl respectively measured solubilities show an average deviation from these equations of ??0.10 and ??0.08 g/100 g of saturated solution.

Functionalized polymers for binding to solutes in aqueous solutions

DOEpatents

Smith, Barbara F.; Robison, Thomas W.

2006-11-21

A functionalized polymer for binding a dissolved molecule in an aqueous solution is presented. The polymer has a backbone polymer to which one or more functional groups are covalently linked. The backbone polymer can be such polymers as polyethylenimine, polyvinylamine, polyallylamine, and polypropylamine. These polymers are generally water-soluble, but can be insoluble when cross-linked. The functional group can be for example diol derivatives, polyol derivatives, thiol and dithiol derivatives, guest-host groups, affinity groups, beta-diphosphonic acids, and beta-diamides

Complications in complexation kinetics for lanthanides with DTPA using dye probe molecules in aqueous solution

DOE PAGES

Larsson, K.; Cullen, T. D.; Mezyk, S. P.; ...

2017-05-17

The complexation kinetics for the polyaminopolycarboxylic ligand DTPA to lanthanides in acidic aqueous solution were investigated using the dye ligand displacement technique and stopped-flow spectroscopy. Significant rate differences were obtained for different dye probes used, indicating that the kinetics of the dissociation of the dye molecule significantly impacts the overall measured kinetics when using this common methodology. The conditions of the solution also influenced the dye-lanthanide-DTPA interactions, which reconciled previously disparate data in the literature.

Radiolysis aspects of the aqueous self-cooled blanket concept and the problem of tritium extraction

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

Bruggeman, A.; Snykers, M.; DeRegge, P.

1988-09-01

In the Aqueous Self-Cooled Blanket (ASCB) concept, an aqueous /sup 6/Li solution in a metallic structure is used as a fusion reactor shielding-breeding blanket. Radiolysis effects could be very important for the design and the use of an ASCB. Although many aspects of the radiation chemistry of water and dilute aqueous solutions are now reasonably well understood, it is not possible to predict the radiochemical behaviour of the concentrated candidate ASCB solutions quantitatively. However, by means of a worst case calculation for a possible ASCB for the Next European Torus (NET) it is shown that even with an important ratemore » of water decomposition the ASCB concept is still workable. Gas bubbles and explosive mixtures can be avoided by increasing the pressure in the neutron irradiated zone and by extracting and/or recombining the radiolytically produced hydrogen and oxygen. This could require an additional inert gas loop, which could also be used as part of the tritium extraction installation.« less

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.

Carbon nanotube scanning probe for imaging in aqueous environment

NASA Technical Reports Server (NTRS)

Stevens, Ramsey M.; Nguyen, Cattien V.; Meyyappan, M.

2004-01-01

Carbon nanotubes (CNTs) used as a probe for scanning probe microscopy has become one of the many potential usages of CNTs that is finding real applications in scientific research and industrial communities. It has been proposed that the unique mechanical buckling properties of the CNT would lessen the imaging force exerted on the sample and, thus, make CNT scanning probes ideal for imaging soft materials, including biological samples in liquid environments. The hydrophobic nature of the CNT graphitic sidewall is clearly chemically incompatible with the aqueous solution requirements in some biological imaging applications. In this paper, we present electron micrograph results demonstrating the instability of CNT scanning probes when submerged in aqueous solution. Moreover, we also introduce a novel approach to resolve this chemical incompatibility problem. By coating the CNT probe with ethylenediamine, thus rendering the CNT probe less hydrophobic, we demonstrate the liquid imaging capability of treated CNT probes. Experimental data for imaging in aqueous solutions are presented, which include an ultrathin Ir film and DNA molecules on a mica surface.

Acid and alkali effects on the decomposition of HMX molecule: a computational study.

PubMed

Zhang, Chaoyang; Li, Yuzhen; Xiong, Ying; Wang, Xiaolin; Zhou, Mingfei

2011-11-03

The stored and wasted explosives are usually in an acid or alkali environment, leading to the importance of exploring the acid and alkali effects on the decomposition mechanism of explosives. The acid and alkali effects on the decomposition of HMX molecule in gaseous state and in aqueous solution at 298 K are studied using quantum chemistry and molecular force field calculations. The results show that both H(+) and OH(-) make the decomposition in gaseous state energetically favorable. However, the effect of H(+) is much different from that of OH(-) in aqueous solution: OH(-) can accelerate the decomposition but H(+) cannot. The difference is mainly caused by the large aqueous solvation energy difference between H(+) and OH(-). The results confirm that the dissociation of HMX is energetically favored only in the base solutions, in good agreement with previous HMX base hydrolysis experimental observations. The different acid and alkali effects on the HMX decomposition are dominated by the large aqueous solvation energy difference between H(+) and OH(-).

Method for producing catalysis from coal

DOEpatents

Farcasiu, Malvina; Derbyshire, Frank; Kaufman, Phillip B.; Jagtoyen, Marit

1998-01-01

A method for producing catalysts from coal is provided comprising mixing an aqueous alkali solution with the coal, heating the aqueous mixture to treat the coal, drying the now-heated aqueous mixture, reheating the mixture to form carbonized material, cooling the mixture, removing excess alkali from the carbonized material, and recovering the carbonized material, wherein the entire process is carried out in controlled atmospheres, and the carbonized material is a hydrocracking or hydrodehalogenation catalyst for liquid phase reactions. The invention also provides for a one-step method for producing catalysts from coal comprising mixing an aqueous alkali solution with the coal to create a mixture, heating the aqueous mixture from an ambient temperature to a predetermined temperature at a predetermined rate, cooling the mixture, and washing the mixture to remove excess alkali from the treated and carbonized material, wherein the entire process is carried out in a controlled atmosphere.

Method for producing catalysts from coal

DOEpatents

Farcasiu, M.; Derbyshire, F.; Kaufman, P.B.; Jagtoyen, M.

1998-02-24

A method for producing catalysts from coal is provided comprising mixing an aqueous alkali solution with the coal, heating the aqueous mixture to treat the coal, drying the now-heated aqueous mixture, reheating the mixture to form carbonized material, cooling the mixture, removing excess alkali from the carbonized material, and recovering the carbonized material, wherein the entire process is carried out in controlled atmospheres, and the carbonized material is a hydrocracking or hydrodehalogenation catalyst for liquid phase reactions. The invention also provides for a one-step method for producing catalysts from coal comprising mixing an aqueous alkali solution with the coal to create a mixture, heating the aqueous mixture from an ambient temperature to a predetermined temperature at a predetermined rate, cooling the mixture, and washing the mixture to remove excess alkali from the treated and carbonized material, wherein the entire process is carried out in a controlled atmosphere. 1 fig.

Three dimensional electrode for the electrolytic removal of contaminants from aqueous waste streams

DOEpatents

Spiegel, Ella F.; Sammells, Anthony F.

2001-01-01

Efficient and cost-effective electrochemical devices and processes for the remediation of aqueous waste streams. The invention provides electrolytic cells having a high surface area spouted electrode for removal of heavy metals and oxidation of organics from aqueous environments. Heavy metal ions are reduced, deposited on cathode particles of a spouted bed cathode and removed from solution. Organics are efficiently oxidized at anode particles of a spouted bed anode and removed from solution. The method of this inventions employs an electrochemical cell having an anolyte compartment and a catholyte compartment, separated by a microporous membrane, in and through which compartments anolyte and catholyte, respectively, are circulated. A spouted-bed electrode is employed as the cathode for metal deposition from contaminated aqueous media introduced as catholyte and as the anode for oxidation of organics from contaminated aqueous media introduced as anolyte.

Structural characterization of environmentally relevant ternary uranyl citrate complexes present in aqueous solutions and solid state materials.

PubMed

Basile, Madeline; Unruh, Daniel K; Flores, Erin; Johns, Adam; Forbes, Tori Z

2015-02-14

Organic acids are important metal chelators in environmental systems and tend to form soluble complexes in aqueous solutions, ultimately influencing the transport and bioavailability of contaminants in surface and subsurface waters. This is particularly true for the formation of uranyl citrate complexes, which have been utilized in advanced photo- and bioremediation strategies for soils contaminated with nuclear materials. Given the complexity of environmental systems, the formation of ternary or heterometallic uranyl species in aqueous solutions are also expected, particularly with Al(iii) and Fe(iii) cations. These ternary forms are reported to be more stable in aqueous solutions, potentially enhancing contaminant mobility and uptake by organisms, but the exact coordination geometries of these soluble molecular complexes have not been elucidated. To provide insight into the nature of these species, we have developed a series of geochemical model compounds ([(UO(2))(2)Al(2)(C(6)H(4)O(7))(4)](6-) (U(2)Al(2)), [(UO(2))(2)Fe(2)(C(6)H(4)O(7))(4)](6-) (U(2)Fe(2)-1) and [(UO(2))(2)Fe(2)(C(6)H(4)O(7))(4)(H(2)O)(2)](6-) (U(2)Fe(2)-2) and [(UO(2))(2)Fe(4)(OH)(4)(C(6)H(4)O(7))(4)](8-) (U(2)Fe(4))) that were characterized by single-crystal X-ray diffraction and vibrational spectroscopy. Mass spectroscopy was then employed to compare the model compounds to species present in aqueous solutions to provide an enhanced understanding of the ternary uranyl citrate complexes that could be relevant in natural systems.

Effect of Microwave-Assisted Extraction on the Phenolic Compounds and Antioxidant Capacity of Blackthorn Flowers.

PubMed

Lovrić, Vanja; Putnik, Predrag; Kovačević, Danijela Bursać; Jukić, Marijana; Dragović-Uzelac, Verica

2017-06-01

This research was undertaken to investigate the influence of extraction parameters during microwave-assisted extraction on total phenolic content, total flavonoids, total hydroxycinnamic acids and total flavonols of blackthorn flowers as well as to evaluate the antioxidant capacity by two different methods (2,2-diphenyl-1-picrylhydrazyl free radical scavenging capacity and ferric reducing antioxidant power assays). The investigated extraction parameters were: solvent type and volume fraction of alcohol in solvent (50 and 70% aqueous solutions of ethanol and methanol), extraction time (5, 15 and 25 min) and extraction temperature (40, 50 and 60 °C) controlled by microwave power of 100, 200 and 300 W. Multivariate analysis of variance (MANOVA) was used to evaluate the differences at a 95% confidence level (p≤0.05). The obtained results show that aqueous solution of ethanol was more appropriate solvent for extraction of phenolic compounds (total flavonoids, total hydroxycinnamic acids and total flavonols) than aqueous solution of methanol. The amount of phenolic compounds was higher in 70% aqueous solution of ethanol or methanol, while higher antioxidant capacity was observed in 50% aqueous solution of methanol. Higher temperature of extraction improved the amount of phenolic compounds and also antioxidant capacity determined by 2,2-diphenyl-1-picrylhydrazyl free radical scavenging capacity assay. Extensive duration of extraction (15- to 25-minute interval) has a significant effect only on the increase of total phenolic content, while specific phenolic compound content and antioxidant capacity were the highest when microwave extraction time of 5 min was applied.

SEPARATION OF THORIUM FROM URANIUM

DOEpatents

Bane, R.W.

1959-09-01

A description is given for the separation of thorium from uranium by forming an aqueous acidic solution containing ionic species of thorium, uranyl uranium, and hydroxylamine, flowing the solution through a column containing the phenol-formaldehyde type cation exchange resin to selectively adsorb substantially all the thorium values and a portion of the uranium values, flowing a dilute solution of hydrochloric acid through the column to desorb the uranium values, and then flowing a dilute aqueous acidic solution containing an ion, such as bisulfate, which has a complexing effect upon thortum through the column to desorb substantially all of the thorium.

SEPARATION OF URANIUM FROM ZIRCONIUM AND NIOBIUM BY SOLVENT EXTRACTION

DOEpatents

Voiland, E.E.

1958-05-01

A process for separation of the uranium from zirconium and/or niobium values contained in 3 to 7M aqueous nitric acid solutions is described. This is accomplished by adding phosphoric acid anions to the nitric acid solution containing the uranium, zirconium, and/or niobium in an amount sufficient to make the solution 0.05 to 0.2M in phosphate ion and contacting the solution with an organic water-immiscible solvent such as MEK, whereby the uranyl values are taken up by the extract phase while the zirconium and niobium preferentially remain in the aqueous raffinate.

Water Evaporation from Acoustically Levitated Aqueous Solution Droplets.

PubMed

Combe, Nicole A; Donaldson, D James

2017-09-28

We present a systematic study of the effect of solutes on the evaporation rate of acoustically levitated aqueous solution droplets by suspending individual droplets in a zero-relative humidity environment and measuring their size as a function of time. The ratios of the early time evaporation rates of six simple salts (NaCl, NaBr, NaNO 3 , KCl, MgCl 2 , CaCl 2 ) and malonic acid to that of water are in excellent agreement with predictions made by modifying the Maxwell equation to include the time-dependent water activity of the evaporating aqueous salt solution droplets. However, the early time evaporation rates of three ammonium salt solutions (NH 4 Cl, NH 4 NO 3 , (NH 4 ) 2 SO 4 ) are not significantly different from the evaporation rate of pure water. This finding is in accord with a previous report that ammonium sulfate does not depress the evaporation rate of its solutions, despite reducing its water vapor pressure, perhaps due to specific surface effects. At longer evaporation times, as the droplets approach crystallization, all but one (MgCl 2 ) of the solution evaporation rates are well described by the modified Maxwell equation.

Process for the preparation of lactic acid and glyceric acid

DOEpatents

Jackson, James E [Haslett, MI; Miller, Dennis J [Okemos, MI; Marincean, Simona [Dewitt, MI

2008-12-02

Hexose and pentose monosaccharides are degraded to lactic acid and glyceric acid in an aqueous solution in the presence of an excess of a strongly anionic exchange resin, such as AMBERLITE IRN78 and AMBERLITE IRA400. The glyceric acid and lactic acid can be separated from the aqueous solution. Lactic acid and glyceric acid are staple articles of commerce.