Removal of cadmium from aqueous solution using marine green algae, Ulva lactuca

Directory of Open Access Journals (Sweden)

Mohamed M. Ghoneim

2014-01-01

Full Text Available The present study aimed to evaluate the efficiency of marine algae for removal of metals from the aqueous solution. The green alga, Ulva lactuca, collected from the intertidal zone of the Suez Bay, northern part of the Red Sea was used to reduce cadmium levels from the aqueous solutions. The biosorption mechanisms of Cd2+ ions onto the algal tissues were examined using various analytical techniques: Fourier-transform infrared spectroscopy (FT-IR and Scanning electron microscopy (SEM. Results indicated that at the optimum pH value of 5.5; about 0.1 g of U. lactuca was enough to remove 99.2% of 10 mg L−1 Cd2+ at 30 °C in the aqueous solutions. The equilibrium data were well fitted with the Langmuir and Freundlich isotherms. The monolayer adsorption capacity was 29.1 mg g−1. The calculated RL and ‘n’ values have proved the favorability of cadmium adsorption onto U. lactuca. The desorption test revealed that HCl was the best for the elution of metals from the tested alga. In conclusion, the seaweed U. lactuca was the favorable alternative of cadmium removal from water.

Pitting morphologies of zirconium base alloys in aqueous and non aqueous chloride media

International Nuclear Information System (INIS)

Palit, G.C.; Gadiyar, H.S.

1988-01-01

Pitting morphology of zirconium and Zr-Cr alloys in aqueous chloride and nonaqueous methanol + 0.4 per cent HCl solution was investigated and observed to follow different modes in these two environments. While in aqueous chloride solution pitting was transgranular and randomly oriented, in methanol-chloride solution pits were observed to initiate and propagate along the grain boundaries. In aqueous chloride solution very irregular and sponge like zirconium metal was formed inside the pit while in methanol-chloride solution the pits were crystallographic in nature. Optical microscopy has revealed that pits preferentially initiate and propagate along scratch line in aqueous chloride solution, but such was not the case in nonaqueous methanol-chloride solution. The nature and the mechanism operating in the catastropic failure of these materials are investigated. (author). 10 refs., 11 figs

Formulation and stability of an extemporaneously compounded oral solution of chlorpromazine HCl.

Science.gov (United States)

Prohotsky, Daniel L; Juba, Katherine M; Zhao, Fang

2014-12-01

Chlorpromazine is a phenothiazine antipsychotic which is often used in hospice and palliative care to treat hiccups, delirium, and nausea. With the discontinuation of the commercial oral solution concentrate, there is a need to prepare this product by extemporaneous compounding. This study was initiated to identify an easy-to-prepare formulation for the compounding pharmacist. A stability study was also conducted to select the proper storage conditions and establish the beyond-use date. Chlorpromazine HCl powder and the Ora-Sweet® syrup vehicle were used to prepare the 100 mg/mL solution. Once the feasibility was established, a batch of the solution was prepared and packaged in amber plastic prescription bottles for a stability study. These samples were stored at refrigeration (2-8°C) or room temperature (20-25°C) for up to 3 months. At each monthly time point, the samples were evaluated by visual inspection, pH measurement, and high performance liquid chromatography (HPLC). A separate forced stability study was conducted to confirm that the HPLC method was stability indicating. A clear and colorless solution of 100 mg/mL chlorpromazine HCl was obtained by dissolving the drug powder in Ora-Sweet® with moderate agitation. The stability study results indicated that this solution product remained unchanged in visual appearance or pH at both refrigeration and room temperature for up to 3 months. The HPLC results also confirmed that all stability samples retained 93.6-101.4% of initial drug concentration. Chlorpromazine HCl solution 100 mg/mL can be compounded extemporaneously by dissolving chlorpromazine HCl drug powder in Ora-Sweet®. The resulting product is stable for at least three months in amber plastic prescription bottles stored at either refrigeration or room temperature.

Formation of fine solid particles from aqueous solutions of sodium chloropalladate by gamma-ray irradiation

International Nuclear Information System (INIS)

Hatada, Motoyoshi; Fujita, Iwao; Korekawa, Kei-ichi.

1994-10-01

Studies have been carried out on the radiation chemical formation of palladium fine particles in argon saturated aqueous solutions of sodium chloropalladate without organic stabilizer. The solutions were irradiated with gamma-rays from a cobalt gamma-ray source and the irradiated solutions were subjected to the dynamic light scattering analysis for the particle diameter measurements, and to the UV-visible optical absorption spectroscopy for the measurements of turbidity (absorption at 700 nm) and remaining chloropalladate ion concentrations in the solution. In the solution of pH = 1.95 by HCl, the turbidity increased after the irradiation and then decreased with time. The concentration of remaining palladate ion in the solution decreased by the irradiation, but it gradually increased with time after the irradiation. These phenomena were qualitatively explained by the reaction scheme in that a precursor to the solid particles still exists in the solution after the irradiation was terminated, and that intermediates including the precursor reacted with chloride ion to re-form chloropalladate ions. The average diameter of the particles after the irradiation was ca. 20 nm and it increased with time to 40 nm at 2.75 kGy, and to 80 nm at 8.25 kGy absorption of radiation. The solution of pH = 0.65 by HCl was found to give lower yields of particles than those observed for the solution of pH = 1.95, and to give the particles of diameters about 150-200 nm. In the solution containing HClO 4 instead of HCl, palladium particles were also formed by the irradiation, whereas no backward reaction after the irradiation was observed due to the low concentration of chloride ion in the solution. The average diameter of the particles after the irradiation was about 300 nm and increased with time after the irradiation to a final values which was found to depend on pH of the solution and dose. (author)

Biosorption of mercury from aqueous solutions using highly characterised peats

Directory of Open Access Journals (Sweden)

A.M. Rizzuti

2015-02-01

Full Text Available This research investigated the biosorption of mercury from aqueous solutions by six highly characterised peats. Samples of the peats were tested both in unaltered condition and after being treated with hydrochloric acid (HCl to free up any occupied exchange sites. Other variables tested were sample dose, contact time, mixing temperature, and the concentration and pH of the mercury solution. Desorption studies were also performed, and tests were done to determine whether the peats could be re-used for mercury biosorption. The results indicate that all six peat types biosorb mercury from aqueous solutions extremely well (92−100 % removal and that their mercury removal capacities are not significantly affected by manipulation of the various factors tested. The factor that had the greatest impact on the mercury removal capacities of the peats was the pH of the mercury solution. The optimal mercury solution pH for mercury removal was in the range 5−7 for four of the peats and in the range 2−3 for the other two. The desorption results indicate that it may be possible to recover up to 41 % of the removed mercury. All of the peat types tested can be repeatedly re-used for additional mercury biosorption cycles. Hence, their disposal should not become a hazardous waste problem.

The separation of uranium ions by natural and modified diatomite from aqueous solution

Energy Technology Data Exchange (ETDEWEB)

Sprynskyy, Myroslav, E-mail: sprynsky@yahoo.com [Department of Environmental Chemistry and Bioanalytics, Faculty of Chemistry, Nicolaus Copernicus University, 7 Gagarina Str., 87-100 Torun (Poland); Kovalchuk, Iryna [Department of Environmental Chemistry and Bioanalytics, Faculty of Chemistry, Nicolaus Copernicus University, 7 Gagarina Str., 87-100 Torun (Poland); Institute of Adsorption and Problem of Endoecology, National Academy of Sciences of Ukraine, 13 General Naumov Str., 03164 Kyiv (Ukraine); Buszewski, Boguslaw [Department of Environmental Chemistry and Bioanalytics, Faculty of Chemistry, Nicolaus Copernicus University, 7 Gagarina Str., 87-100 Torun (Poland)

2010-09-15

In this work the natural and the surfactant modified diatomite has been tested for ability to remove uranium ions from aqueous solutions. Such controlling factors of the adsorption process as initial uranium concentration, pH, contact time and ionic strength have been investigated. Effect of ionic strength of solution has been examined using the solutions of NaCl, Na{sub 2}CO{sub 3} and K{sub 2}SO{sub 4}. The pseudo-first order and the pseudo-second order models have been used to analyze the adsorption kinetic results, whereas the Langmuir and the Freundlich isotherms have been used to the equilibrium adsorption data. The effects of the adsorbent modification as well as uranium adsorption on the diatomite surface have been studied using X-ray powder diffraction, scanning electron microscopy and FTIR spectroscopy. The maximum adsorption capacities of the natural and the modified diatomite towards uranium were 25.63 {mu}mol/g and 667.40 {mu}mol/g, respectively. The desorptive solutions of HCl, NaOH, Na{sub 2}CO{sub 3}, K{sub 2}SO{sub 4}, CaCO{sub 3}, humic acid, cool and hot water have been tested to recover uranium from the adsorbent. The highest values of uranium desorption (86%) have been reached using 0.1 M HCl.

The separation of uranium ions by natural and modified diatomite from aqueous solution.

Science.gov (United States)

Sprynskyy, Myroslav; Kovalchuk, Iryna; Buszewski, Bogusław

2010-09-15

In this work the natural and the surfactant modified diatomite has been tested for ability to remove uranium ions from aqueous solutions. Such controlling factors of the adsorption process as initial uranium concentration, pH, contact time and ionic strength have been investigated. Effect of ionic strength of solution has been examined using the solutions of NaCl, Na(2)CO(3) and K(2)SO(4). The pseudo-first order and the pseudo-second order models have been used to analyze the adsorption kinetic results, whereas the Langmuir and the Freundlich isotherms have been used to the equilibrium adsorption data. The effects of the adsorbent modification as well as uranium adsorption on the diatomite surface have been studied using X-ray powder diffraction, scanning electron microscopy and FTIR spectroscopy. The maximum adsorption capacities of the natural and the modified diatomite towards uranium were 25.63 micromol/g and 667.40 micromol/g, respectively. The desorptive solutions of HCl, NaOH, Na(2)CO(3), K(2)SO(4), CaCO(3), humic acid, cool and hot water have been tested to recover uranium from the adsorbent. The highest values of uranium desorption (86%) have been reached using 0.1M HCl. Copyright 2010 Elsevier B.V. All rights reserved.

Densities and apparent molar volumes of HClO4(aq) and Yb(ClO4)3(aq) at elevated temperatures and pressures

International Nuclear Information System (INIS)

Hakin, Andrew W.; Lukacs, Michael J.; Jin Lianliu

2004-01-01

Relative densities have been measured for acidified aqueous solutions of ytterbium perchlorate {Yb(ClO 4 ) 3 } at approximately T=(348.15, 373.15, 398.15, and 423.15) K and p=(10.0, 20.0, and 30.0) MPa over the concentration range 0.01624≤m 2 /(mol · kg -1 ) ≤ 0.2531 using an optically coupled vibrating tube densimeter (OCVTD). Experimental apparent molar volumes have been calculated from the density measurements, and apparent molar volumes for the aqueous perchlorate salt have been calculated using Young's rule. The application of Young's rule requires apparent molar volumes for aqueous perchloric acid (HClO 4 ) solutions over extended temperature and pressure ranges. These values were calculated from densities for aqueous HClO 4 solutions that were measured using the OCVTD at the same temperatures and pressures as those used to investigate the density surface of the acidified aqueous Yb(ClO 4 ) 3 solutions. The temperature, pressure, and composition surfaces of the apparent molar volumes for Yb(ClO 4 ) 3 (aq) and HClO 4 (aq) have been modelled using Pitzer ion-interaction equations. Apparent molar volumes at infinite dilution obtained from these models have been compared to those which can be calculated using the semi-empirical Helgeson, Kirkham, and Flowers equations of state. Values for the apparent molar volume at infinite dilution of the ytterbium trivalent cation have also been calculated using simple additivity principles

Electrochemical characterization of Zr-based thin film metallic glass in hydrochloric aqueous solution

International Nuclear Information System (INIS)

Chuang, Ching-Yen; Liao, Yi-Chia; Lee, Jyh-Wei; Li, Chia-Lin; Chu, Jinn P.; Duh, Jenq-Gong

2013-01-01

Recently thin film metallic glass represents a class of promising engineering materials for structural applications. In this work, the Zr-based thin film metallic glass (TFMG) was fabricated on the Si and AISI 420 substrates using a Zr–Cu–Ni–Al alloy and pure Zr metal targets by a pulsed DC magnetron sputtering system. The chemical compositions, crystalline structures, microstructures and corrosion behavior in hydrochloric (HCl) aqueous solutions of Zr-based TFMGs were investigated. The results showed that the surface morphologies of Zr-based TFMG were very smooth. A compact and dense structure without columnar structure was observed. The amorphous structure of Zr-based TFMG was characterized by the X-ray diffractometer and transmission electron microscopy analyses. After the potentiodynamic polarization test, the better corrosion resistance was achieved for the Zr-based TFMG coated AISI 420 in 1 mM HCl aqueous solution. Based on the surface morphologies and chemical analysis results of the corroded surfaces, the pitting, crevice corrosion and filiform corrosion were found. The corrosion mechanisms of the Zr-based TFMG were discussed in this work. - Highlights: ► Zr-based thin film metallic glass with amorphous structure. ► Better corrosion resistance of Zr-based thin film metallic glass observed. ► Pitting, crevice and filiform corrosion reactions revealed. ► The Cu-rich corrosion products found in the pit. ► Nanowire and flaky corrosion products formed adjacent to the filiform corrosion path

First results on the sorption behaviour of Rutherfordium from HCl/HF containing aqueous solution

Energy Technology Data Exchange (ETDEWEB)

Schumann, D.; Nitsche, H. [Technische Univ. Dresden (Germany); Taut, S. [Forschungszentrum Rossendorf e.V. (FZR), Dresden (Germany); Jost, D.T.; Gaeggeler, H.W. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Yakushev, A.B.; Buklanov, G.V.; Domanov, V.P.; Lien Din Thi [Joint Inst. for Nuclear Research, Dubna (Russian Federation); Kubica, B.; Misiak, R.; Szeglowski, Z. [NINP Cracow (Poland)

1997-09-01

Rutherfordium shows strong sorption on the cation exchanger DOWEX 50x8 at a concentration of 0.1 M HCl/10{sup -2} M HF. This shows that Rf behaves under these conditions differently from Hf and Zr and more like Th under these conditions. (author) 1 fig., 5 refs.

Densities and apparent molar volumes of HClO{sub 4}(aq) and Yb(ClO{sub 4}){sub 3}(aq) at elevated temperatures and pressures

Energy Technology Data Exchange (ETDEWEB)

Hakin, Andrew W. E-mail: hakin@uleth.ca; Lukacs, Michael J.; Jin Lianliu

2004-09-01

Relative densities have been measured for acidified aqueous solutions of ytterbium perchlorate {l_brace}Yb(ClO{sub 4}){sub 3}{r_brace} at approximately T=(348.15, 373.15, 398.15, and 423.15) K and p=(10.0, 20.0, and 30.0) MPa over the concentration range 0.01624{<=}m{sub 2}/(mol {center_dot} kg{sup -1}) {<=} 0.2531 using an optically coupled vibrating tube densimeter (OCVTD). Experimental apparent molar volumes have been calculated from the density measurements, and apparent molar volumes for the aqueous perchlorate salt have been calculated using Young's rule. The application of Young's rule requires apparent molar volumes for aqueous perchloric acid (HClO{sub 4}) solutions over extended temperature and pressure ranges. These values were calculated from densities for aqueous HClO{sub 4} solutions that were measured using the OCVTD at the same temperatures and pressures as those used to investigate the density surface of the acidified aqueous Yb(ClO{sub 4}){sub 3} solutions. The temperature, pressure, and composition surfaces of the apparent molar volumes for Yb(ClO{sub 4}){sub 3}(aq) and HClO{sub 4}(aq) have been modelled using Pitzer ion-interaction equations. Apparent molar volumes at infinite dilution obtained from these models have been compared to those which can be calculated using the semi-empirical Helgeson, Kirkham, and Flowers equations of state. Values for the apparent molar volume at infinite dilution of the ytterbium trivalent cation have also been calculated using simple additivity principles.

Photo-degradation behaviour of roseoflavin in some aqueous solutions

International Nuclear Information System (INIS)

Tyagi, A.; Penzkofer, A.; Mathes, T.; Hegemann, P.

2010-01-01

An absorption and emission spectroscopic characterization of roseoflavin (8-dimethylamino-8-demethyl-riboflavin, RoF) in aqueous solutions was carried out. The studies were concentrated on roseoflavin in pH 8 phosphate buffer. Absorption cross-section spectra, fluorescence excitation spectra, fluorescence quantum distributions, fluorescence quantum yields and fluorescence lifetimes were determined. The fluorescence of RoF is quenched by photo-induced intra-molecular charge-transfer at room temperature. The photo-degradation of RoF in un-buffered water, in Tris-HCl buffer, and in phosphate buffer was studied. Phosphate buffer and to a smaller extent Tris buffer catalyse the RoF photo-degradation. Photo-excitation of the primary photoproduct, 8-methylamino-riboflavin (8-MNH-RF), enhanced the RoF degradation by triplet 8-MNH-RF - singlet RoF excitation transfer with subsequent triplet-state RoF degradation.

Photo-degradation behaviour of roseoflavin in some aqueous solutions

Science.gov (United States)

Tyagi, A.; Penzkofer, A.; Mathes, T.; Hegemann, P.

2010-03-01

An absorption and emission spectroscopic characterization of roseoflavin (8-dimethylamino-8-demethyl-riboflavin, RoF) in aqueous solutions was carried out. The studies were concentrated on roseoflavin in pH 8 phosphate buffer. Absorption cross-section spectra, fluorescence excitation spectra, fluorescence quantum distributions, fluorescence quantum yields and fluorescence lifetimes were determined. The fluorescence of RoF is quenched by photo-induced intra-molecular charge-transfer at room temperature. The photo-degradation of RoF in un-buffered water, in Tris-HCl buffer, and in phosphate buffer was studied. Phosphate buffer and to a smaller extent Tris buffer catalyse the RoF photo-degradation. Photo-excitation of the primary photoproduct, 8-methylamino-riboflavin (8-MNH-RF), enhanced the RoF degradation by triplet 8-MNH-RF - singlet RoF excitation transfer with subsequent triplet-state RoF degradation.

Photo-degradation behaviour of roseoflavin in some aqueous solutions

Energy Technology Data Exchange (ETDEWEB)

Tyagi, A. [Institut II - Experimentelle und Angewandte Physik, Universitaet Regensburg, Universitaetsstrasse 31, D-93053 Regensburg (Germany); Penzkofer, A., E-mail: alfons.penzkofer@physik.uni-regensburg.de [Institut II - Experimentelle und Angewandte Physik, Universitaet Regensburg, Universitaetsstrasse 31, D-93053 Regensburg (Germany); Mathes, T.; Hegemann, P. [Institut fuer Biologie/Experimentelle Biophysik, Humboldt Universitaet zu Berlin, Invalidenstrasse 42, D-10115 Berlin (Germany)

2010-03-24

An absorption and emission spectroscopic characterization of roseoflavin (8-dimethylamino-8-demethyl-riboflavin, RoF) in aqueous solutions was carried out. The studies were concentrated on roseoflavin in pH 8 phosphate buffer. Absorption cross-section spectra, fluorescence excitation spectra, fluorescence quantum distributions, fluorescence quantum yields and fluorescence lifetimes were determined. The fluorescence of RoF is quenched by photo-induced intra-molecular charge-transfer at room temperature. The photo-degradation of RoF in un-buffered water, in Tris-HCl buffer, and in phosphate buffer was studied. Phosphate buffer and to a smaller extent Tris buffer catalyse the RoF photo-degradation. Photo-excitation of the primary photoproduct, 8-methylamino-riboflavin (8-MNH-RF), enhanced the RoF degradation by triplet 8-MNH-RF - singlet RoF excitation transfer with subsequent triplet-state RoF degradation.

Search for chemical separations of the element 106 homologues in HF and HF-HCl media

International Nuclear Information System (INIS)

Trubert, D.; Monroy-Guzman, F.; Hussonnois, M.; Brillard, L.; Le Naour, C.; Constantinescu, O.

1996-01-01

In order to study the chemical properties of element 263 106 in aqueous media, fast, efficient and reproducible chromatographic separations were tested on its assumed homologous: Mo, W and U. Corroborative static and dynamic off-line experiments have shown that after fixation of these three elements on anion-exchange resin in HF medium, selective elution could be achieved by using suitable concentration of HCl - HF and HCl solutions. Separations of short-lived W isotopes, produced through heavy ion irradiation were also performed on-line. (author). 27 refs., 14 figs

The etching of InP in HCl solutions : a chemical mechanism

NARCIS (Netherlands)

Notten, P.H.L.

1984-01-01

The etch rate of InP in solutions of high HCl concentration was shown to be independent of the applied potential ina wide potential range negative with respect to the flatband value. Dissolution of the solid led to the formation of PH3.The etch rate, which was not mass-transport controlled, was

The extraction of uranyl nitrate and chloride in octaethyltetraamidopyrophosphate (OETAPP)-HCl, HNO3 systems

International Nuclear Information System (INIS)

Jankowska, M.; Kulawik, J.; Mikulski, J.

1975-01-01

The extraction of uranium was studied in the system of 0.1 M OETAPP in CHCl 3 /HCl or HNO 3 . The distribution coefficients of HCl and HNO 3 were calculated as a function of OETAPP concentration. The amount of OETAPP in the aqueous phase containing HCl and HNO 3 was found from the measurements of surface tension of this phase. The distribution of HCl or HNO 3 between the organic and aqueous phases was studied as a function of the concentration of the acid used in the aqueous phase. The solvation energy of the extracted complexes was calculated from the measured potential differences. Cohesion and adhesion energies of the studied systems are also given. (author)

Vanadium Flow Battery Electrolyte Synthesis via Chemical Reduction of V2O5 in Aqueous HCl and H2SO4.

Energy Technology Data Exchange (ETDEWEB)

Small, Leo J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Pratt, Harry [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Staiger, Chad [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Martin, Rachel Irene [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Anderson, Travis Mark [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Chalamala, Babu [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Soundappan, Thiagarajan [Univ. of Washington, Seattle, WA (United States); Tiwari, Monika [Univ. of Washington, Seattle, WA (United States); Subarmanian, Venkat R. [Univ. of Washington, Seattle, WA (United States)

2017-01-01

We report a simple method to synthesize V 4+ (VO 2+ ) electrolytes as feedstock for all- vanadium redox flow batteries (RFB). By dissolving V 2 O 5 in aqueous HCl and H 2 SO 4 , subsequently adding glycerol as a reducing agent, we have demonstrated an inexpensive route for electrolyte synthesis to concentrations >2.5 M V 4+ (VO 2+ ). Electrochemical analysis and testing of laboratory scale RFB demonstrate improved thermal stability across a wider temperature range (-10-65 degC) for V 4+ (VO 2+ ) electrolytes in HCl compared to in H 2 SO 4 electrolytes.

Air-supplied pinhole discharge in aqueous solution for the inactivation of Escherichia coli

Science.gov (United States)

Suganuma, Ryota; Yasuoka, Koichi

2018-04-01

An air-supplied pinhole discharge in aqueous solution has been developed to provide a short-lived and odorless bactericide to replace current conventional disinfectants such as O3, ClO-, HClO, and ClO2. The pinhole discharge that was initiated inside a water bubble generated hydrogen peroxide (H2O2) and nitrous acid (HNO2) simultaneously. The concentrations of H2O2, HNO2, and HNO3 were 16.3, 13.9, and 17.4 mg/L, respectively when flow rates of NaCl solution and air were 72 and 12.5 mL/min, respectively. The pH value of the solution was 3.87, and HO2 radicals were generated from the reaction of H2O2 with HNO2. The efficacy of sterilization of discharge-treated water was evaluated by changing the acetic solutions. A 4-orders-of-magnitude decrease in Escherichia coli survival rate was observed after treatment with a sodium citrate solution of pH 3.2 for 60 s.

Polypyrrole-polyaniline/Fe{sub 3}O{sub 4} magnetic nanocomposite for the removal of Pb(II) from aqueous solution

Energy Technology Data Exchange (ETDEWEB)

Afshar, Amirhossein; Sadjadi, Seyed Abolfazl Seyed; Mollahosseini, Afsaneh; Eskandarian, Mohammad Reza [Iran University of Science and Technology, Tehran (Iran, Islamic Republic of)

2016-02-15

Lead ion which is engaged in aqueous solution has been successfully removed. A novel technique was utilized for the separation and absorption of Pb(II) ions from aqueous solution. Magnetic Fe{sub 3}O{sub 4} coated with newly investigated polypyrrole-polyaniline nanocomposite was used for the removal of extremely noxious Pb(II). Characteristic of the prepared magnetic nanocomposite was done using X-ray diffraction pattern, Field emission scanning electron microscopy (FE-SEM), Fourier transform-infrared spectroscopy (FT-IR) and energy dispersive x-ray spectroscopy (EDX). Up to 100% adsorption was found with 20mg/L Pb(II) aqueous solution in the range of pH=8-10. Adsorption results illustrated that Pb(II) removal efficiency by the nanocomposite increased with an enhance in pH. Adsorption kinetics was best expressed by the pseudo-second-order rate form. Isotherm data fitted well to the Freundlich isotherm model. Upon using HCl and HNO{sub 3}, 75% PPy-PAn/Fe{sub 3}O{sub 4} nanocomposite, desorption experiment showed that regenerated adsorbent can be reused successfully for two successive adsorption-desorption cycles without appreciable loss of its original capacity.

Boron removal from aqueous solutions by ion-exchange resin: Column sorption-elution studies

International Nuclear Information System (INIS)

Koese, T. Ennil; Oztuerk, Nese

2008-01-01

A column sorption-elution study was carried out by using a strong base anion-exchange resin (Dowex 2 x 8) for the removal of boron from aqueous solutions. The breakthrough curve was obtained as a function of feed flow rate and the total and breakthrough capacity values of the resin were calculated. The boron on the resin was quantitatively eluted with 0.5 M HCl solution at different flow rates. Three consecutive sorption-elution-washing-regeneration-washing cycles were applied to the resin in order to investigate the reusability of the ion-exchange resin. Total capacity values remained almost the same after three sorption-elution-regeneration cycles. The Thomas and the Yoon-Nelson models were applied to experimental data to predict the breakthrough curves and to determine the characteristic column parameters required for process design. The results proved that the models would describe the breakthrough curves well

Thermodynamic properties of aqueous solutions with citrate ions. Compressibility studies in aqueous solutions of citric acid

International Nuclear Information System (INIS)

Apelblat, Alexander; Korin, Eli; Manzurola, Emanuel

2013-01-01

Highlights: • Over a wide range of concentrations and temperatures sound velocities were measured in aqueous solutions of citric acid. • Compressibility properties of citric acid solutions are thermodynamically characterized. • Changes in the structure of water when citric acid is dissolved are discussed. -- Abstract: Sound velocities in aqueous solutions of citric acid were measured from 15 °C to 50 °C in 5 °C intervals, within the 0.1 mol · kg −1 to 5.0 mol · kg −1 concentration range. These sound velocities served to evaluate the isentropic and isothermal compressibilities, the apparent molar compressibilities, the isochoric thermal pressure coefficients, changes of the cubic expansion coefficients with pressure at constant temperature, the changes of heat capacities with volume and hydration numbers of citric acid in aqueous solutions

Self-assembly of a helical zinc-europium complex: speciation in aqueous solution and luminescence

Directory of Open Access Journals (Sweden)

Emmanuel eDeiters

2013-09-01

Full Text Available Two new tridentate(NNO-bidentate(NN compartmental ligands, HL5 and HL6, are synthesized from pyridine and benzimidazole synthons. They react in aqueous solution under physiological conditions with ZnII, LnIII, or a mixture thereof, to yield complexes of different stoichiometries, 1:3, 2:2, 2:3, 1:1:3, the speciation of which is established by UV-visible titrations and ESI mass spectrometry. Photophysical studies of the EuIII-containing solutions in Tris-HCl 0.1 M (pH = 7.4 show that lanthanide luminescence arises from a unique N6O3 coordination site with pseudo D3 symmetry. Relevant parameters such as crystal field splitting, lifetime, radiative lifetime and intrinsic quantum yield perfectly match those reported for dinuclear 4f-4f helicates in which the EuIII ion has the same coordination environment.

By-products formation during degradation of isoproturon in aqueous solution. II: Chlorination.

Science.gov (United States)

Mascolo, G; Lopez, A; James, H; Fielding, M

2001-05-01

After a previous study in which the considered oxidant was ozone (Part I), a laboratory investigation has been carried out to study the degradation of the herbicide isoproturon during its reaction with another oxidant, i.e. chlorine, in aqueous solution (Part II; this paper). The specific aim was to identify the by-products formed. The effects of pH and the presence of bromide ions were studied. Reactions have been carried out at room temperature, in phosphate buffered aqueous solutions, at four pHs (6, 7, 8 and 9). By-products identification was first performed using relatively high initial reagent concentrations which were analytically convenient ([isoproturon] = 40 mg/l, [HClO + ClO-] = 160 mg Cl/l, [Br-] = 80 mg/l). In follow-up studies, the by-products identified during this preliminary step were searched for when using concentration values closer to those actually encountered at real water treatment plants ([isoproturon] = 0.4 and 0.004 mg/l, [HClO + ClO-] = 1.6 mg Cl/l, [Br-] = 0.8 and 0.008 mg/l). Under all of the studied conditions, the results showed that isoproturon is completely degraded and that it decays much faster in the presence of bromide. The pH has a negligible influence when bromide ions are absent. On the contrary, if bromide ions are present, the isoproturon decay is slower at higher pH values. High-performance liquid chromatography-mass spectrometry (HPLC-MS) analyses have led to the identification of several by-products as a result of simultaneous oxidation and substitution reactions, both occurring on the aromatic ring of the herbicide. However, the more abundant by-products are those resulting from the oxidation of the isoproturon aromatic ring. As far as halogenated by-products are concerned, the higher the bromide ion concentration the higher the ratio of brominated to chlorinated by-products. On the basis of the analytical results, a pathway for isoproturon degradation under the studied conditions is proposed.

Study on Corrosion Inhibition Efficiency of Stem Alkaloid Extract of Different Varieties of Holy Basil on Aluminium in HCl Solution

Energy Technology Data Exchange (ETDEWEB)

Kumpawat, Nutan; Chaturvedi, Alok; Upadhyay, R. K. [Synthetic and Surface Science Laboratory, Ajmer (India)

2012-08-15

Corrosion inhibition efficiencies of holy basil on Al in HCl solution were studied by weight loss and thermometric methods in presence and in absence of stem extract of three different varieties of holy basil viz. ocimum basilicum (E{sub B}), ocimum canum (E{sub C}) and ocimum sanctum (E{sub S}). Inhibition efficiency increases with the increasing concentration of stem extract and decreases with increases in acid strength. Results show that all varieties under study are good corrosion inhibitors, among which, E{sub B} is most effective. Maximum inhibition efficiency was found 97.09% in 0.5N HCl solution with 0.6% stem extract. The Langmuir adsorption isotherm indicates that surface coverage also increases with increasing in the concentration of extract of stem in HCl solution.

Study on Corrosion Inhibition Efficiency of Stem Alkaloid Extract of Different Varieties of Holy Basil on Aluminium in HCl Solution

International Nuclear Information System (INIS)

Kumpawat, Nutan; Chaturvedi, Alok; Upadhyay, R. K.

2012-01-01

Corrosion inhibition efficiencies of holy basil on Al in HCl solution were studied by weight loss and thermometric methods in presence and in absence of stem extract of three different varieties of holy basil viz. ocimum basilicum (E B ), ocimum canum (E C ) and ocimum sanctum (E S ). Inhibition efficiency increases with the increasing concentration of stem extract and decreases with increases in acid strength. Results show that all varieties under study are good corrosion inhibitors, among which, E B is most effective. Maximum inhibition efficiency was found 97.09% in 0.5N HCl solution with 0.6% stem extract. The Langmuir adsorption isotherm indicates that surface coverage also increases with increasing in the concentration of extract of stem in HCl solution

Application of Azolla for 2, 4, 6-Trichlorophenol (TCP Removal from Aqueous Solutions

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Mohammad Ali Zazouli

2013-11-01

Full Text Available Background & Aims of the Study: The 2, 4, 6-Trichlorophenol (TCP is a phenolic compound which it can produce adverse effects on human and environment. Therefore, the removal of these compounds is necessary. The aim of this study is the investigation of TCP removal by using Azolla filiculoides biomass. Materials & Methods: The Azolla biomass was dried in the sunlight, and then it was crushed and sieved to particle sizes in range of 1-2 mm. Next treated with 0.1M HCl for a period of 5h. The Azolla was washed with distilled water and it was used as adsorbent. The effect of operating parameters such as pH, contact time, TCP concentration and adsorbent dose on the TCP removal efficiency was investigated. The residues concentration of TCP was measured by spectrophotometer in λ max of 296 nm. Results: In optimum condition (pH 3, contact time 120 min , adsorbent dose 10 gr/l and TCP concentration 10 ppm, Azolla was able to remove 95% of TCP from aqueous solutions. The equilibrium data follows the Langmuir isotherm and the proper kinetic model is pseudo-second model. Conclusions: Adsorption process by Azolla filiculoides is an efficient method for removal of 2, 4, 6-Trichlorophenol from aqueous solutions.

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

Science.gov (United States)

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.

Isomers of Poly Aminophenol: Chemical Synthesis, Characterization, and Its Corrosion Protection Aspect on Mild Steel in 1 M HCl

OpenAIRE

Thenmozhi, G.; Arockiasamy, P.; Santhi, R. Jaya

2014-01-01

The oxidative chemical polymerizations of three isomers of aminophenol, ortho, meta, and para (PoAP, PmAP, and PpAP), were performed in aqueous HCl using ammonium persulfate as an oxidant at 0–3°C. The synthesized polymers were characterized by employing elemental analysis, GPC, UV-VIS-NIR, FT-IR, XRD, and TGA. The corrosion inhibition effect of these three polymers on mild steel in 1 M HCl solution was studied by using electrochemical techniques such as potentiodynamic polarization and elect...

Influence of the composition of the aqueous phase on the behavior of the system FeCl3-HCl-DPE

International Nuclear Information System (INIS)

Ramirez, F. de M.; Jimenez-Reyes, M.

1981-07-01

We studied the influence of the aqueous phase composition upon an extraction system in which, at room temperature (20 0 C +- 3 0 C) using the dissolvents FeCl 3 -HCl-di-isopropyl ether the third phase phenomena is present after one minute of agitation. Our results showed that principally the hydrochloric acid dissolvent produced each of the three phases at given concentration levels as well as determined the nature of the chemical composition in each phase. (author)

Thermodynamic properties of potassium chloride aqueous solutions

Science.gov (United States)

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.

Radiation-induced nitration of organic compounds in aqueous solutions

International Nuclear Information System (INIS)

Ershov, B.G.; Gordeev, A.V.; Bykov, G.L.; Moisy, P.

2012-01-01

Radiolysis in aqueous nitrate and acetic acid solutions and nitrate/nitric acid and phenol was studied. The radiolysis of these solutes occurs with circle NO 2 radical, which is the active nitrating agent. Accumulation of nitromethane and nitrite was determined during γ-irradiation of aqueous solutions containing acetic and nitrate solutions. Irradiation of aqueous phenol-nitrate/nitric acid solutions results in the formation of 2- and 4-nitrophenols.

Radiation-induced nitration of organic compounds in aqueous solutions

Energy Technology Data Exchange (ETDEWEB)

Ershov, B.G.; Gordeev, A.V.; Bykov, G.L. [Russian Academy of Sciences, Moscow (Russian Federation). Frumkin Inst. of Physical Chemistry and Electrochemistry; Moisy, P. [CEA, Bagnols sur Ceze (France). Nuclear Energy Div.

2012-07-01

Radiolysis in aqueous nitrate and acetic acid solutions and nitrate/nitric acid and phenol was studied. The radiolysis of these solutes occurs with {sup circle} NO{sup 2} radical, which is the active nitrating agent. Accumulation of nitromethane and nitrite was determined during {gamma}-irradiation of aqueous solutions containing acetic and nitrate solutions. Irradiation of aqueous phenol-nitrate/nitric acid solutions results in the formation of 2- and 4-nitrophenols.

Gel chromatographic behavior of Tc-99m-labeled compounds in aqueous solution

International Nuclear Information System (INIS)

Suzuki, T.; Wagner, H.N. Jr.; Burns, H.D.; Dannals, F.F.

1984-01-01

The purpose of this study was to elucidate the interaction of Tc-99m-labeled compounds (Tc-99m 0/sub 4/-bar, Tc-99m glucoheptonate, Tc-99m DTPA, Tc-99m disofenin) with the chromatographic gels, to determine their relative molecular sizes and molecular structures in aqueous solution, which are based on their biomenbrane transport mechanism and quality control analysis. Each Tc-99m-labeled compound was eluted and analyzed by three different gel chromatrography systems varying buffers: Sephadex G-25, Sephadex LH-20 and Bio-Gel P-4. The best separation between the elution peaks of all compounds except Tc-99m glucoheptonate was achieved on Sephadex G-25 in methanol-0.025OM Tris-HCL buffer (pH 7.6) (1:1) which could avoid the aromatic interaction with the gels. Tc-99m glucoheptonate was well eluted only on a Bio-Gel P-4 column but its elution peak was not separated from other compounds' peaks. The elution of Tc-99m disofenin was delayed on Sephadex G-25 gel and Bio-Gel P-4 columns in 0.9% NaCl and Tris-HCl buffer(ph 7.6) and on Sephadex LH-20 column in methanol-Tris-HCl buffer, because of the aromatic ring interaction with the gels. The relative molecular size index ( Kav ) calculated from the elution volume of the gel chromatography. Kav of Tc-99m 0/sub 4/-bar(MW=163), Tc-99m DTPA (MW=492?) and TC-99m disofenin (MW=707) on Sephadex G-25 in methanol-0.025OM Tris-HCl buffer(pH 7.6) (1:1), which was the most suitable combination of the gel and the buffer, were 0.976, 0.477 and 0.200, respectively. They inversely correlated with their estimated molecular weight. The interaction of Tc-99m-labeled compounds with the chromatographic gels should be considered in quality control procedure for Tc-99m radiopharamaceuticals

Studies on the sorption behaviours of Th(IV) and U(VI) from aqueous sulphate solutions using impregnated resin

International Nuclear Information System (INIS)

Khatab, A.F.; Sheta, M.E.; Mahfouz, M.G.; Tolba, A.A.

2007-01-01

The sorption behaviours of thorium (IV) and uranium (VI) from aqueous sulphate solutions have been studied using n-dodecylamine and tri-n-octylamine (TOA) dissolved in benzene and impregnated onto amberlite XAD-4 (styrene-divinyl benzene copolymer). The sorption behaviours were evaluated as a function of free acidity, salting out effect, ph value, equilibrium time, V/m ratio, initial metal ion concentration, loaded amine concentration and sorption temperature. The equilibrium time for Th(IV) and U(VI) sorption from aqueous sulphate solution was found to be 90 and 60 minutes, respectively. The sorption of Th(IV) was quantitatively at ph range 3.7-4.3 and at 4.3-5.2 for U(VI). The sorption capacity of the impregnated resin was determined by batch method and it was found to be 0.031 and 0.033 mmol/g for Th(IV) and U(VI), respectively. Elution of Th(IV) from thorium-loaded impregnated resin was quantitatively achieved by using 2 mol/l HNO 3 and by using 0.1 mol/l HCl for U(VI)

Chromatography of actinides on anion-exchange paper, behaviour of the elements U, Np Pu Am in acid, aqueous and alcohol-water solutions

International Nuclear Information System (INIS)

Collin, Michel

1969-01-01

A preliminary study of actinide migration on ion exchange paper has been carried out on trace amounts with a view to subsequent application in micro-analysis. The first tests have made it possible to define the factors having an effect on the migrational velocities of aqueous and alcohol-water solutions of HCl and HNO 3 . The behaviour, of actinides has then been studied in non-saline acid solutions. The results obtained for each element separately are interesting from the point of view of their mutual separation. This analytical technique has finally been applied successfully to the migration of 300 μg of uranium deposited from a 1 ml volume of solution. (author) [fr

Extraction of hafnium by 1-phenyl-3-methyl-4-benzoyl-5-pyralozone from aqueous-alcoholic solutions

International Nuclear Information System (INIS)

Hala, J.; Prihoda, J.

1975-01-01

Extraction of hafnium by 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (HL) in benzene, toluene, chloroform and tetrachloromethane from aqueous-alcoholic solutions of the formal acidity of 2M-HClO 4 was studied. Methyl, ethyl, n- and isopropyl, tert-butyl and allyl alcohol as well as ethylene glycol monomethyl ether and propylene glycol were used as organic components of the mixed aqueous-organic phase. Their presence in some cases resulted in a synergic increase in the distribution ratio of hafnium. The increase is interpreted using the results of a slope analysis and measurements of the alcohol distribution and the relative permittivity of the organic phase. It is suggested that HfL 4 molecules were solvated by alcohol molecules in the organic phase. At high alcohol concentration synergism changed into antagonism. This was caused by changes in the distribution of HL and its interaction with the alcohol in the organic phase. (author)

Metal ion removal from aqueous solution using physic seed hull.

Science.gov (United States)

Mohammad, Masita; Maitra, Saikat; Ahmad, Naveed; Bustam, Azmi; Sen, T K; Dutta, Binay K

2010-07-15

The potential of physic seed hull (PSH), Jantropha curcas L. as an adsorbent for the removal of Cd(2+) and Zn(2+) metal ions from aqueous solution has been investigated. It has been found that the amount of adsorption for both Cd(2+) and Zn(2+) increased with the increase in initial metal ions concentration, contact time, temperature, adsorbent dosage and the solution pH (in acidic range), but decreased with the increase in the particle size of the adsorbent. The adsorption process for both metal ions on PSH consists of three stages-a rapid initial adsorption followed by a period of slower uptake of metal ions and virtually no uptake at the final stage. The kinetics of metal ions adsorption on PSH followed a pseudo-second-order model. The adsorption equilibrium data were fitted in the three adsorption isotherms-Freundlich, Langmuir and Dubinin-Radushkevich isotherms. The data best fit in the Langmuir isotherm indication monolayer chemisorption of the metal ions. The adsorption capacity of PSH for both Zn(2+) and Cd(2+) was found to be comparable with other available adsorbents. About 36-47% of the adsorbed metal could be leached out of the loaded PSH using 0.1M HCl as the eluting medium. 2010 Elsevier B.V. All rights reserved.

Adsorption of uranium from aqueous solution using biochar produced by hydrothermal carbonization

International Nuclear Information System (INIS)

Zhi-bin Zhang; East China Institute of Technology, Fuzhou; China University of Geosciences, Wuhan; China University of Geosciences, Wuhan; Xiao-hong Cao; Yun-hai Liu; East China Institute of Technology, Fuzhou; Ping Liang; East China Institute of Technology, Fuzhou; China University of Geosciences, Wuhan

2013-01-01

The ability of biochar produced by hydrothermal carbonization (HTC) has been explored for the removal and recovery of uranium from aqueous solutions. The micro-morphology and structure of HTC were characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. The influences of different experimental parameters such as solution pH, initial concentration, contact time, ionic strength and temperature on adsorption were investigated. The HTC showed the highest uranium sorption capacity at initial pH of 6.0 and contact time of 50 min. Adsorption kinetics was better described by the pseudo-second-order model and adsorption process could be well defined by the Langmuir isotherm. The thermodynamic parameters, ΔGdeg(298 K), ΔHdeg and ΔSdeg were determined to be -14.4, 36.1 kJ mol -1 and 169.7 J mol -1 K -1 , respectively, which demonstrated the sorption process of HTC towards U(VI) was feasible, spontaneous and endothermic in nature. The adsorbed HTC could be effectively regenerated by 0.05 mol/L HCl solution for the removal and recovery of U(VI). Complete removal (99.9 %) of U(VI) from 1.0 L industry wastewater containing 15.0 mg U(VI) ions was possible with 2.0 g HTC. (author)

The photochemistry of neptunium in aqueous perchloric acid solutions

International Nuclear Information System (INIS)

Friedman, H.A.; Toth, L.M.; Osborne, M.M.

1979-01-01

The photochemistry of neptunium ions in aqueous perchloric acid has been investigated using 254 and 300 nm UV radiation. In the absence of other reagents, Np(IV) and (V) oxidized to Np(VI), in a stepwise fashion, with individual quantum efficiencies for each step that vary from 0.02 to 0.004. Decreasing acid concentration favors the Np(IV) → Np(V) reaction whereas it hinders the Np(V) → Np(VI) photo-oxidation. When ethanol, acetaldehyde and other mild reducing agents are added to neptunium-perchloric acid solutions which are then photolyzed, the Np species are reduced to Np(III) in a stepwise fashion with individual quantum efficiencies that vary from 0.07 to 0.006. The overall photoredox reactions of neptunium are subject to competing secondary product reactions that become significant as the photolysis products accumulate. Absorption spectrophotometry was used to monitor the changes in Np oxidation states and reference spectra of the various Np oxidation states are given for 1.0 N HClO 4 . The Np species have absorption bands in the 300 to 1320 nm region that obey Beer's law only when they were properly resolved. (author)

21 CFR 524.1200b - Kanamycin ophthalmic aqueous solution.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Kanamycin ophthalmic aqueous solution. 524.1200b... (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS OPHTHALMIC AND TOPICAL DOSAGE FORM NEW ANIMAL DRUGS § 524.1200b Kanamycin ophthalmic aqueous solution. (a) Specifications. The drug, which is in an aqueous...

Formation and disappearance of superoxide radicals in aqueous solutions

International Nuclear Information System (INIS)

Allen, A.O.; Bielski, B.H.J.

1980-01-01

A literature review of superoxide radicals in aqueous solutions is presented covering the following: history; methods of formation of aqueous HO 2 /HO 2 - by radiolysis and photolysis, electrolysis, mixing nonaqueous solutions into water, chemical reactions, enzymatic generation of O 2 - , and photosensitization; and properties of HO 2 /O 2 - in aqueous solution, which cover spontaneous dismutation rates, pk and absorption spectra, catalyzed dismutation, thermodynamics and the so-called Haber-Weiss Reaction

Preliminary study on lithium-salt aqueous solution blanket

International Nuclear Information System (INIS)

Yoshida, Hiroshi; Naruse, Yuji; Yamaoka, Mitsuaki; Ohara, Atsushi; Ono, Kiyoshi; Kobayashi, Shigetada.

1992-06-01

Aqueous solution blanket using lithium salts such as LiNO 3 and LiOH have been studied in the US-TIBER program and ITER conceptual design activity. In the JAERI/LANL collaboration program for the joint operation of TSTA (Tritium Systems Test Assembly), preliminary design work of blanket tritium system for lithium ceramic blanket, aqueous solution blanket and liquid metal blanket, have been performed to investigate technical feasibility of tritium demonstration tests using the TSTA. Detail study of the aqueous solution blanket concept have not been performed in the Japanese fusion program, so that this study was carried out to investigate features of its concept and to evaluated its technical problems. The following are the major items studied in the present work: (i) Neutronics of tritium breeding ratio and shielding performance Lithium concentration, Li-60 enrichment, beryllium or lead, composition of structural material/beryllium/solution, heavy water, different lithium-salts (ii) Physicochemical properties of salts Solubility, corrosion characteristics and compatibility with structural materials, radiolysis (iii) Estimation of radiolysis in ITER aqueous solution blanket. (author)

Thermodynamic equilibrium model to predict the cobalt distribution coefficient in the CoCl2--HCl--H2O--TBP liquid--liquid extraction system

International Nuclear Information System (INIS)

Nevarez, M.; Bautista, R.G.

1976-01-01

The development of a thermodynamic equilibrium model to predict the cobalt distribution coefficient in the CoCl 2 -HCl-H 2 O-TBP system is described. The model makes use of the various aqueous phase cobaltous chloride complexes stoichiometric stability constants expressed as their degree of formation, their mechanism of extraction into the organic phase, and the equilibrium constant for the extraction reaction. The model was verified by the good agreement between the calculated cobalt distribution coefficients and those obtained experimentally both in the present study and published by other investigators. The optimum extraction of cobalt by the TBP occurred at an HCl equilibrium aqueous place concentration between 8.5 and 9.5M. The development of efficient procedures for the separation and concentration of important industrial metals from their aqueous solutions by liquid-liquid extraction has recently been given impetus by the realization of an impending shortage of energy and mineral resources. Liquid-liquid extraction is one of the few methods by which it is possible to quantitatively separate elements which are similar in properties. The use of liquid-liquid extraction to separate cobalt and nickel, which very frequently occur in nature together, is an important separation problem in nonferrous metallurgy. There is some fundamental information available in the chemical literature regarding the mechanism and equilibrium thermodynamic properties of selected liquid-liquid extraction systems. This research effort shows how this available information can be utilized to improve existing separation and concentration theory and technique. The development and application of a thermodynamic equilibrium model for describing the liquid-liquid extraction of cobaltous chloride from aqueous HCl solutions by tributyl phosphate (TBP) using experimental data obtained in this investigation and from the literature are presented

Aqueous polyethylene oxide solutions

International Nuclear Information System (INIS)

Breen, J.

1987-01-01

A number of aspects concerning the reorientation of polymer, water and ion hydration complexes have been studied in aqueous solution of polyethylene oxide (PEO). The polymer dynamics are investigated by 1 H-PEO and 13 C-PEO nuclear relaxation experiments. 162 refs.; 30 figs.; 19 tabs

Diffusion coefficients of paracetamol in aqueous solutions

International Nuclear Information System (INIS)

Ribeiro, Ana C.F.; Barros, Marisa C.F.; Veríssimo, Luís M.P.; Santos, Cecilia I.A.V.; Cabral, Ana M.T.D.P.V.; Gaspar, Gualter D.; Esteso, Miguel A.

2012-01-01

Highlights: ► Mutual diffusion coefficients of paracetamol in aqueous dilute solutions. ► Influence of the thermodynamic factors on the variation of their mutual diffusion coefficients. ► Estimation of the mutual limiting diffusion coefficients of the molecular, D m 0 , and ionized forms, D ± 0 , of this drug. - Abstract: Binary mutual diffusion coefficients measured by the Taylor dispersion method, for aqueous solutions of paracetamol (PA) at concentrations from (0.001 to 0.050) mol·dm −3 at T = 298.15 K, are reported. From the Nernst–Hartley equation and our experimental results, the limiting diffusion coefficient of this drug and its thermodynamic factors are estimated, thereby contributing in this way to a better understanding of the structure of such systems and of their thermodynamic behaviour in aqueous solution at different concentrations.

Bioprospecting of gum kondagogu (Cochlospermum gossypium) for bioremediation of uranium (VI) from aqueous solution and synthetic nuclear power reactor effluents

International Nuclear Information System (INIS)

Sashidhar, R.B.; Selvi, S. Kalaignana; Vinod, V.T.P.; Kosuri, Tanuja; Raju, D.; Karuna, R.

2015-01-01

An ecofriendly green chemistry method using a natural biopolymer, Gum Kondagogu (GK) for the removal of U (VI) from aqueous, simulated nuclear effluents was studied. The adsorption characteristic of GK towards U (VI) from aqueous solution was studied at varied pH, contact time, adsorbent dose, initial U (VI) concentration and temperature using UV–Visible spectroscopy and ICP-MS. Maximum adsorption was seen at pH 4, 0.1% GK with 60 min contact time at room temperature. The GK- U (VI) composite was characterized by FT-IR, zeta potential, TEM and SEM-EDAX. The Langmuir isotherm was found to be 487 mg of U (VI) g −1 of GK. The adsorption capacity and (%) of U (VI) was found to be 490 ± 5.4 mg g −1 and 98.5%. Moreover adsorption of U (VI) by GK was not influenced by other cations present in the simulated effluents. The adsorbed U (VI) was efficiently stripped from composite using 1 M HCl. - Highlights: • An eco-friendly method for removal of U (VI) from simulated nuclear effluents by Gum Kondagogu. • The Langmuir and Freundlich isotherm indicated favourable adsorption. • The adsorption (%) of U (VI) by GK was found to be 98.5%. • Desorption studies on biosorbed metal ions showed that HCl was a good eluent

Hydrogen production by sodium borohydride in NaOH aqueous solution

Science.gov (United States)

Wang, Q.; Zhang, L. F.; Zhao, Z. G.

2018-01-01

The kinetics of hydrolysis reaction of NaBH4 in NaOH aqueous solution is studied. The influence of pH of the NaOH aqueous solution on the rate of hydrogen production and the hydrogen production efficiency are studied for the hydrolysis reaction of NaBH4. The results show that the activation energy of hydrolysis reaction of NaBH4 increased with the increase of the initial pH of NaOH aqueous solution.With the increasing of the initial pH of NaOH aqueous solution, the rate of hydrogen production and hydrogen production efficiency of NaBH4 hydrolysis decrease.

Knudsen thermogravimetry approach to the thermodynamics of aqueous solutions

International Nuclear Information System (INIS)

Schiraldi, Alberto; Signorelli, Marco; Fessas, Dimitrios

2013-01-01

Highlights: ► Knudsen cells were designed to replace standard TG pans for desorption experiments. ► The Knudsen effusion data allow determination of water activity of aqueous solutions. ► This methods can replace the traditional isopiestic approach for aqueous solutions. ► The Gibbs–Duhem relationship was used to fit the experimental data. -- Abstract: The use of isothermal TGA with Knudsen-like cells allows determination of the thermodynamic activity of water, a W . The typical experiment implies a slow dehydration of the aqueous solution at constant temperature in dynamic vacuum conditions. The method is alternative to the classical isopiestic approach and offers the advantage of a continuous record on increasing the solute concentration. These data can be directly treated according to the classical thermodynamic relationships drawn from the Gibbs–Duhem expression to evaluate the activity and osmotic coefficient of the aqueous solutions of electrolytes and non-electrolytes, and, in the case of electrolytes, allow determination of solubility of the solute. Discrepancies with respect to the literature data are observed when the viscosity of the systems becomes too high, as in the case of sugars with a very large solubility. Such a mismatch may however be accounted for either slowing the dehydration rate with use of a narrower Knudsen orifice, or correcting the experimental a W with a calibration curve. The same approach can be applied to non-aqueous solutions

Electroerosion of metal in aqueous solution for sample introduction into an inductively coupled plasma mass spectrometer

International Nuclear Information System (INIS)

Goltz, Douglas; Boileau, Michael; Reinfelds, Gundars

2003-01-01

When high current (1-10 A cm -2 ) is applied between two conductive samples (metals) in aqueous solution, electroerosion occurs on the surface as a result of electrolysis and possibly collisions of dissolved ions with the metal surface. The power supply for the electroerosion apparatus in this work was a modified spark source unit. Current could be varied in intervals of 2.5, 5 and 10 A in either half-wave (unipolar) or full-wave (bipolar) output. The electroeroded metal forms a colloidal suspension in aqueous solution with particle sizes of the order of 1-10 μm and possibly larger. The suspension is readily dissolved using a small amount (100 μl) of concentrated acid (HCl or HNO 3 ) prior to analysis. Electroerosion of steel and brass in aqueous solution is described both for rapid sample dissolution and as a solid sampling approach for ICP-MS. Some of the electroerosion properties described in this paper include rates of erosion as a function of gap between the conductive samples and solution conductivity. Rates of electroerosion decreased from 120 to 30 μg s -1 as the gap was increased from 2 to 5 mm. Rates of electroerosion also increased significantly from 200 to 1000 μg s -1 as the conductivity of the electroerosion solution increased from 0.01 to 0.05 M NaCl. Interfacing the electroerosion apparatus to an ICP-MS was straight forward, as no special equipment was required. Therefore, the electroerosion apparatus can be used for rapid 'on-line' sample dissolution prior to introduction into an ICP. ICP-MS time profiles of selected metals in stainless steel 308L illustrate the behavior of 52 Cr + , 55 Mn + and 60 Ni + during a typical electroerosion cycle. Aspiration of the colloidal suspension into the ICP did not appear to load the plasma significantly, however, all of the metals produced noisy signals (±10%). A glass concentric nebulizer was used without clogging, so it is likely that the heterogeneous nature of the colloidal suspension caused this effect

Electroerosion of metal in aqueous solution for sample introduction into an inductively coupled plasma mass spectrometer

Science.gov (United States)

Goltz, Douglas; Boileau, Michael; Reinfelds, Gundars

2003-07-01

When high current (1-10 A cm -2) is applied between two conductive samples (metals) in aqueous solution, electroerosion occurs on the surface as a result of electrolysis and possibly collisions of dissolved ions with the metal surface. The power supply for the electroerosion apparatus in this work was a modified spark source unit. Current could be varied in intervals of 2.5, 5 and 10 A in either half-wave (unipolar) or full-wave (bipolar) output. The electroeroded metal forms a colloidal suspension in aqueous solution with particle sizes of the order of 1-10 μm and possibly larger. The suspension is readily dissolved using a small amount (100 μl) of concentrated acid (HCl or HNO 3) prior to analysis. Electroerosion of steel and brass in aqueous solution is described both for rapid sample dissolution and as a solid sampling approach for ICP-MS. Some of the electroerosion properties described in this paper include rates of erosion as a function of gap between the conductive samples and solution conductivity. Rates of electroerosion decreased from 120 to 30 μg s -1 as the gap was increased from 2 to 5 mm. Rates of electroerosion also increased significantly from 200 to 1000 μg s -1 as the conductivity of the electroerosion solution increased from 0.01 to 0.05 M NaCl. Interfacing the electroerosion apparatus to an ICP-MS was straight forward, as no special equipment was required. Therefore, the electroerosion apparatus can be used for rapid 'on-line' sample dissolution prior to introduction into an ICP. ICP-MS time profiles of selected metals in stainless steel 308L illustrate the behavior of 52Cr +, 55Mn + and 60Ni + during a typical electroerosion cycle. Aspiration of the colloidal suspension into the ICP did not appear to load the plasma significantly, however, all of the metals produced noisy signals (±10%). A glass concentric nebulizer was used without clogging, so it is likely that the heterogeneous nature of the colloidal suspension caused this effect.

Electrolytic nature of aqueous sulfuric acid. 2. Acidity.

Science.gov (United States)

Fraenkel, Dan

2012-09-27

In part 1 of this study, I reported that the Debye-Hückel limiting law and the smaller-ion shell (SiS) model of strong electrolyte solutions fit nicely with the experimental mean ionic activity coefficient (γ(±)) of aqueous sulfuric acid as a function of concentration and of temperature when the acid is assumed to be a strong 1-3 electrolyte. Here, I report that the SiS-derived activity coefficient of H(+), γ(H(+)), of the 1-3 acid is comparable to that of aqueous HCl. This agrees with titration curves showing, as well-known, that sulfuric acid in water is parallel in strength to aqueous HCl. The calculated pH is in good accord with the Hammett acidity function, H(0), of aqueous sulfuric acid at low concentration, and differences between the two functions at high concentration are discussed and explained. This pH-H(0) relation is consistent with the literature showing that the H(0) of sulfuric acid (in the 1-9 M range) is similar to those of HCl and the other strong mineral monoprotic acids. The titration of aqueous sulfuric acid with NaOH does not agree with the known second dissociation constant of 0.010 23; rather, the constant is found to be ~0.32 and the acid behaves upon neutralization as a strong diprotic acid practically dissociating in one step. A plausible reaction pathway is offered to explain how the acid may transform, upon base neutralization, from a dissociated H(4)SO(5) (as 3H(+) and HSO(5)(3-)) to a dissociated H(2)SO(4) even though the equilibrium constant of the reaction H(+) + HSO(5)(3-) ↔ SO(4)(2-) + H(2)O, at 25 °C, is 10(-37) (part 1).

Radiolysis of aqueous solutions of insulin. [. gamma. rays

Energy Technology Data Exchange (ETDEWEB)

Foitik, A [Ceskoslovenska Akademie Ved, Prague. Ustav Fyzikalni Chemie a Elektrochemie J. Heyrovskeho; Kopoldova, J [Ceskoslovenska Akademie Ved, Prague. Isotopova Laborator Biologickych Ustavu

1976-08-01

The effect of ionizing radiation on diluted aqueous solutions of insulin is analyzed. The rate of decrease in its level (the loss of polarographic activity) is described by a first-order kinetic equation. The results lead to the concept of a direct effect on macromolecules in 'excited volumes'. The amount of inactivated molecules (i.e., the yield) in this volume is proportional to the solute concentration. In diluted aqueous solutions indirect radiation effects also take place. The paper evaluates these effects.

Removal of mercury from aqueous solutions using activated carbon prepared from agricultural by-product/waste.

Science.gov (United States)

Rao, M Madhava; Reddy, D H K Kumar; Venkateswarlu, Padala; Seshaiah, K

2009-01-01

Removal of mercury from aqueous solutions using activated carbon prepared from Ceiba pentandra hulls, Phaseolus aureus hulls and Cicer arietinum waste was investigated. The influence of various parameters such as effect of pH, contact time, initial metal ion concentration and adsorbent dose for the removal of mercury was studied using a batch process. The experiments demonstrated that the adsorption process corresponds to the pseudo-second-order-kinetic models and the equilibrium adsorption data fit the Freundlich isotherm model well. The prepared adsorbents ACCPH, ACPAH and ACCAW had removal capacities of 25.88 mg/g, 23.66 mg/g and 22.88 mg/g, respectively, at an initial Hg(II) concentration of 40 mg/L. The order of Hg(II) removal capacities of these three adsorbents was ACCPH>ACPAH>ACCAW. The adsorption behavior of the activated carbon is explained on the basis of its chemical nature. The feasibility of regeneration of spent activated carbon adsorbents for recovery of Hg(II) and reuse of the adsorbent was determined using HCl solution.

Removal of copper, nickel and zinc ions from aqueous solution by chitosan-8-hydroxyquinoline beads

Energy Technology Data Exchange (ETDEWEB)

Barros, Francisco C.F.; Dias, Francisco S.; Vasconcellos, Luiz C.G. [Departamento de Quimica Organica e Inorganica, Campus do Pici - Universidade Federal do Ceara, Fortaleza (Brazil); Sousa, Francisco W. [Departamento de Engenharia Hidraulica e Ambiental, Campus do Pici - Universidade Federal do Ceara, Fortaleza (Brazil); Cavalcante, Rivelino M.; Carvalho, Tecia V.; Queiroz, Danilo C. [Departamento de Quimica Analitica e Fisico Quimica, Campus do Pici - Universidade Federal do Ceara, Fortaleza (Brazil); Nascimento, Ronaldo F.

2008-03-15

In this work, 8-hydroxyquinoline is used as the active sites in cross-linked chitosan beads with epichlorohydrin (CT-8HQ). The CT-8HQ material was shaped in bead form and used for heavy metal removal from aqueous solution. The study was carried out at pH 5.0 with both batch and column methods and the maximum adsorption capacity of metal ions by the CT-8HQ was attained in 4 h in the batch experiment. The adsorption capacity order was: Cu{sup 2+} > Ni{sup 2+} > Zn{sup 2+} for both mono- and multi-component systems with batch conditions. From breakthrough curves with column conditions, the adsorption capacity followed the order Cu{sup 2+} > Zn{sup 2+} > Ni{sup 2+} for both mono- and multi-component systems. The CT-8HQ beads maintained good metal adsorption capacity for all five cycles with absorbent restoration achieved with the use of 1.0 mol L{sup -1} HCl solution, with 90% regeneration. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

Adsorption of phosphate from aqueous solutions and sewage using zirconium loaded okara (ZLO): Fixed-bed column study

International Nuclear Information System (INIS)

Nguyen, T.A.H.; Ngo, H.H.; Guo, W.S.; Pham, T.Q.; Li, F.M.; Nguyen, T.V.; Bui, X.T.

2015-01-01

This study explores the potential of removing phosphorus from aqueous solutions and sewage by Zr(IV)-loaded okara (ZLO) in the fixed-bed column. Soybean residue (okara) was impregnated with 0.25 M Zr(IV) solution to prepare active binding sites for phosphate. The effect of several factors, including flow rate, bed height, initial phosphorus concentration, pH and adsorbent particle size on the performance of ZLO was examined. The maximum dynamic adsorption capacity of ZLO for phosphorus was estimated to be 16.43 mg/g. Breakthrough curve modeling indicated that Adams–Bohart model and Thomas model fitted the experimental data better than Yoon–Nelson model. After treatment with ZLO packed bed column, the effluent could meet the discharge standard for phosphorus in Australia. Successful desorption and regeneration were achieved with 0.2 NaOH and 0.1 HCl, respectively. The results prove that ZLO can be used as a promising phosphorus adsorbent in the dynamic adsorption system. - Highlights: • Dynamic adsorption of P from water and wastewater by Zr(IV)-loaded okara was tested. • Effects of column design parameters on the adsorption performance were investigated. • The dynamic adsorption capacity of Zr(IV)-loaded okara for P was reasonably high. • The spent column was effectively regenerated with 0.2 M NaOH followed by 0.1 M HCl. • Zr(IV)-loaded okara column was efficient in eliminating P from municipal sewage

Adsorption of phosphate from aqueous solutions and sewage using zirconium loaded okara (ZLO): Fixed-bed column study

Energy Technology Data Exchange (ETDEWEB)

Nguyen, T.A.H. [Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology, Sydney (UTS), 15 Broadway, Ultimo, NSW 2007 (Australia); Ngo, H.H., E-mail: ngohuuhao121@gmail.com [Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology, Sydney (UTS), 15 Broadway, Ultimo, NSW 2007 (Australia); Guo, W.S. [Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology, Sydney (UTS), 15 Broadway, Ultimo, NSW 2007 (Australia); Pham, T.Q. [Faculty of Geography, University of Science, Vietnam National University, Hanoi (Viet Nam); Li, F.M. [College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100 (China); Nguyen, T.V. [Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology, Sydney (UTS), 15 Broadway, Ultimo, NSW 2007 (Australia); Bui, X.T. [Environmental Engineering and Management Research Group, Ton Duc Thang University, Ho Chi Minh City (Viet Nam); Faculty of Environment and Natural Resources, Ho Chi Minh City University of Technology-Vietnam National University, Ho Chi Minh City (Viet Nam)

2015-08-01

This study explores the potential of removing phosphorus from aqueous solutions and sewage by Zr(IV)-loaded okara (ZLO) in the fixed-bed column. Soybean residue (okara) was impregnated with 0.25 M Zr(IV) solution to prepare active binding sites for phosphate. The effect of several factors, including flow rate, bed height, initial phosphorus concentration, pH and adsorbent particle size on the performance of ZLO was examined. The maximum dynamic adsorption capacity of ZLO for phosphorus was estimated to be 16.43 mg/g. Breakthrough curve modeling indicated that Adams–Bohart model and Thomas model fitted the experimental data better than Yoon–Nelson model. After treatment with ZLO packed bed column, the effluent could meet the discharge standard for phosphorus in Australia. Successful desorption and regeneration were achieved with 0.2 NaOH and 0.1 HCl, respectively. The results prove that ZLO can be used as a promising phosphorus adsorbent in the dynamic adsorption system. - Highlights: • Dynamic adsorption of P from water and wastewater by Zr(IV)-loaded okara was tested. • Effects of column design parameters on the adsorption performance were investigated. • The dynamic adsorption capacity of Zr(IV)-loaded okara for P was reasonably high. • The spent column was effectively regenerated with 0.2 M NaOH followed by 0.1 M HCl. • Zr(IV)-loaded okara column was efficient in eliminating P from municipal sewage.

Inhibition by Ginkgo leaves extract of the corrosion of steel in HCl and H{sub 2}SO{sub 4} solutions

Energy Technology Data Exchange (ETDEWEB)

Deng Shuduan, E-mail: dengshuduan@163.com [Faculty of Materials Engineering, Southwest Forestry University, Kunming 650224 (China); Li Xianghong [Faculty of Science, Southwest Forestry University, Kunming 650224 (China)

2012-02-15

Highlights: Black-Right-Pointing-Pointer Ginkgo leaves extract (GLE) acts as a good inhibitor for steel in HCl and H{sub 2}SO{sub 4} media. Black-Right-Pointing-Pointer The inhibition efficiency follows the order: HCl > H{sub 2}SO{sub 4}. Black-Right-Pointing-Pointer The adsorption of GLE on steel surface obeys Langmuir adsorption isotherm. Black-Right-Pointing-Pointer GLE behaves as a mixed-type inhibitor in 1.0 M HCl, while cathodic inhibitor in 0.5 M H{sub 2}SO{sub 4}. - Abstract: The inhibition effect of Ginkgo leaves extract (GLE) on the corrosion of cold rolled steel (CRS) in 1.0-5.0 M HCl and 0.5-2.5 M H{sub 2}SO{sub 4} solutions was investigated for the first time by weight loss, potentiodynamic polarization curves, electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM) methods. The results show that GLE is a good inhibitor, and exhibits more efficient in 1.0 M HCl than 0.5 M H{sub 2}SO{sub 4}. The adsorption of GLE on CRS surface obeys Langmuir adsorption isotherm. GLE acts as a mixed-type inhibitor in 1.0 M HCl, while a cathodic inhibitor in 0.5 M H{sub 2}SO{sub 4}.

Radiolysis of aqueous solution of plutonium; Radiolyse des solutions aqueuses de plutonium

Energy Technology Data Exchange (ETDEWEB)

Pages nee Flon, M [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1960-07-01

This study is concerned first with the effects of gamma rays on plutonium aqueous solutions at various valency states, in presence of sulfuric, perchloric, nitric and hydrochloric acids. The main feature is the reduction of Pu VI into Pu V, followed by dismutation from V to IV and VI. For sulfuric and perchloric acid solutions (0,2 N) the following process is given: radiolysis of water produces OH, H{sub 2}O{sub 2}, H and H{sub 2}. H and H{sub 2}O{sub 2} reduce Pu VI while Pu V is oxidised by OH radicals. However the reaction of hydrogen peroxide is slow and leads to an after effect. A parallel study of the action of H{sub 2}O{sub 2} has given a confirmation. Spectrophotometric measurements were carried out on disappearance of Pu VI and formation of Pu IV and it was possible to make determination of G{sub H{sub 2}}{sub O{sub 2}} = 0,8 and G{sub H} - G{sub OH} = 0,8. G{sub H{sub 2}} = 0,41 was measured by gas analysis. The calculation of G{sub {sup -}}{sub H{sub 2}}{sub O} gave 4,35. The re-oxidation of Pu V is dependant on the concentration of sulfate ions. In perchloric acid solution reduction goes on to Pu Ill. Cl{sup -} and NO{sub 3}{sup -} ions inhibit the reduction and even suppress it. The effect of alpha particles both from plutonium and from polonium is very similar to the effect of hydrogen peroxyde. Induction time were observed mainly in presence of HSO{sub 4}{sup -}, depending on the accumulation of H{sub 2}O{sub 2} and (or) of plutonium peroxide. At low acidities, Pu IV peroxide seems to lead to polymer forms. In the more simple cases (H{sub 2}SO{sub 4} and HClO{sub 4} 0,2N), the following yields were found: G (equivalent reduced) = 3.2, G{sub H{sub 2}}{sub O{sub 2}} = 1.35, G{sub H{sub 2}} = 1.6 and G{sub H} - G{sub OH} = 0.1, assuming G{sub HO{sub 2}} = 0.2; and the usual hypothesis on radiolysis of water by alpha particles. Radiation induced oxidation of Pu III into Pu IV was also observed in H{sub 2}SO{sub 4} and HNO{sub 3} aqueous solutions, and

Acetic acid extraction from aqueous solutions using fatty acids

NARCIS (Netherlands)

IJmker, H.M.; Gramblicka, M.; Kersten, Sascha R.A.; van der Ham, Aloysius G.J.; Schuur, Boelo

2014-01-01

A major challenge for production of acetic acid via bio-based routes is cost-effective concentration and purification of the acetic acid from the aqueous solutions, for which liquid–liquid extraction is a possible method. A main challenge in extraction of acetic acid from dilute aqueous solutions is

Rapid removal of uranium from aqueous solutions using magnetic Fe3O4@SiO2 composite particles.

Science.gov (United States)

Fan, Fang-Li; Qin, Zhi; Bai, Jing; Rong, Wei-Dong; Fan, Fu-You; Tian, Wei; Wu, Xiao-Lei; Wang, Yang; Zhao, Liang

2012-04-01

Rapid removal of U(VI) from aqueous solutions was investigated using magnetic Fe(3)O(4)@SiO(2) composite particles as the novel adsorbent. Batch experiments were conducted to study the effects of initial pH, amount of adsorbent, shaking time and initial U(VI) concentrations on uranium sorption efficiency as well as the desorbing of U(VI). The sorption of uranium on Fe(3)O(4)@SiO(2) composite particles was pH-dependent, and the optimal pH was 6.0. In kinetics studies, the sorption equilibrium can be reached within 180 min, and the experimental data were well fitted by the pseudo-second-order model, and the equilibrium sorption capacities calculated by the model were almost the same as those determined by experiments. The Langmuir sorption isotherm model correlates well with the uranium sorption equilibrium data for the concentration range of 20-200 mg/L. The maximum uranium sorption capacity onto magnetic Fe(3)O(4)@SiO(2) composite particles was estimated to be about 52 mg/g at 25 °C. The highest values of uranium desorption (98%) was achieved using 0.01 M HCl as the desorbing agent. Fe(3)O(4)@SiO(2) composite particles showed a good selectivity for uranium from aqueous solution with other interfering cation ions. Present study suggested that magnetic Fe(3)O(4)@SiO(2) composite particles can be used as a potential adsorbent for sorption uranium and also provided a simple, fast separation method for removal of heavy metal ion from aqueous solution. Copyright © 2011 Elsevier Ltd. All rights reserved.

Photolysis of Periodate and Periodic Acid in Aqueous Solution

DEFF Research Database (Denmark)

Sehested, Knud; Kläning, U. K.

1978-01-01

The photochemistry of periodate and periodic acid in aqueous solution was studied (i) by quantum yield measurements at low light intensity (ii) by flash photolysis, and (iii) by photolysis of glassy samples at 77 K. The photochemical studies were supplemented with pulse radiolysis studies...... of aqueous periodate solutions and with kinetic studies using stopped-flow technique. In strongly alkaline solution the photodecomposition of periodate proceeds via formation of O– and IVI. At pH solution O3 P is formed in a small...

Enhancement removal of tartrazine dye using HCl-doped polyaniline and TiO2-decorated PANI particles

Science.gov (United States)

Elsayed, M. A.; Gobara, Mohamed

2016-08-01

HCl-doped polyaniline (HCl-PANI) and titanium dioxide decorated with polyaniline (TiO2-decorated PANI) with different TiO2:PANI ratios were chemically prepared and utilized for the removal of tartrazine (TZ) dye from a synthetic aqueous solution. The mechanism of preparation of the sample suggested that aniline was adsorbed on the TiO2 surface before the polymerization process took place. Samples were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive x-ray spectroscopy and x-ray diffraction. The results showed that HCl-PANI and TiO2-decorated PANI have an amorphous structure. The thermal stability of the prepared samples was characterized using thermo-gravimetric (TG) analysis. HCl-PANI is stable up to 200 °C and the relative weight per cent of PANI in the TiO2-decorated PANI was 20, 25, 40 and 45%. The removal activity of TiO2-decorated PANI via TZ azo dye was investigated under UV light irradiations and compared with HCl-PANI and TiO2 particles. The results indicated the superiority of the TiO2-decorated PANI over pure HCl-PANI and TiO2. However, the excessive PANI percentage tends to form a relatively thick layer, and even aggregates on the surface of TiO2. This hinders the migration of excited electrons from the outer PANI layer to the inner TiO2 particles, which consequently leads to a decrease in the removal efficiency. A possible mechanism for the removal oxidative degradation is also mentioned.

Method of precipitating uranium from an aqueous solution and/or sediment

Science.gov (United States)

Tokunaga, Tetsu K; Kim, Yongman; Wan, Jiamin

2013-08-20

A method for precipitating uranium from an aqueous solution and/or sediment comprising uranium and/or vanadium is presented. The method includes precipitating uranium as a uranyl vanadate through mixing an aqueous solution and/or sediment comprising uranium and/or vanadium and a solution comprising a monovalent or divalent cation to form the corresponding cation uranyl vanadate precipitate. The method also provides a pathway for extraction of uranium and vanadium from an aqueous solution and/or sediment.

Corrosion initiation of stainless steel in HCl solution studied using electrochemical noise and in-situ atomic force microscope

International Nuclear Information System (INIS)

Li Yan; Hu Ronggang; Wang Jingrun; Huang Yongxia; Lin Changjian

2009-01-01

An in-situ atomic force microscope (AFM), optical microscope and electrochemical noise (ECN) techniques were applied to the investigation of corrosion initiations in an early stage of 1Cr18Ni9Ti stainless steel immersed in 0.5 M HCl solution. The electrochemical current noise data has been analyzed using discrete wavelet transform (DWT). For the first time, the origin of wavelet coefficients is discussed based on the correlation between the evolution of the energy distribution plot (EDP) of wavelet coefficients and topographic changes. It is found that the occurrence of initiation of metastable pitting at susceptive sites is resulted from the reductive breakdown of passive film of stainless steel in the diluted HCL solution. The coefficients d 4 -d 6 are originated from metastable pitting, d 7 represents the formation and growth of stable pitting while d 8 corresponds to the general corrosion.

Optical sensing of HCl with phenol red doped sol-gels

International Nuclear Information System (INIS)

Wang Enju; Chow, Kwok-Fan; Wang Wenqun; Wong, Crystal; Yee, Cynthia; Persad, Alvin; Mann, Jonathan; Bocarsly, Andrew

2005-01-01

A dye doped sol-gel for the sensing of hydrochloric acid in solution and/or gaseous phase is described. The sol-gel is obtained by acidic hydrolysis of tetraethoxysilane (TEOS) and phenyltriethoxysilane (Ph-TriEOS) in the presence of phenol red (PR) and further spin-coating onto glass slides. The sensitive response is based on an increase of the absorption band at 510 nm of phenol red entrapped in the sol-gel casting when exposed to HCl solution or gas, due to protonation of the dye. The detection limit of the sol-gel response to moisturized gaseous HCl is below 12 ppm, and its response to HCl in solution falls in the range of 0.01-6 M. The sol-gel coating has a response time of less than 40 s in steady-state, and life-time of more than a year. Weak acids such as acetic acid, benzoic acid, salicylate acid, citrate acid, and carbonic acid do not interfere the response. The responses in acid solutions are completely reversible. In the gaseous phase, response of HCl appears to be moisture sensitive

Optical sensing of HCl with phenol red doped sol-gels

Energy Technology Data Exchange (ETDEWEB)

Wang Enju [Department of Chemistry, St. John' s University, 8000 Utopia Parkway, Jamaica, NY 11439 (United States)]. E-mail: wange@stjohns.edu; Chow, Kwok-Fan [Department of Chemistry, St. John' s University, 8000 Utopia Parkway, Jamaica, NY 11439 (United States); Wang Wenqun [Department of Chemistry, St. John' s University, 8000 Utopia Parkway, Jamaica, NY 11439 (United States); Wong, Crystal [Department of Chemistry, St. John' s University, 8000 Utopia Parkway, Jamaica, NY 11439 (United States); Yee, Cynthia [Department of Chemistry, St. John' s University, 8000 Utopia Parkway, Jamaica, NY 11439 (United States); Persad, Alvin [Department of Chemistry, St. John' s University, 8000 Utopia Parkway, Jamaica, NY 11439 (United States); Mann, Jonathan [Department of Chemistry, Princeton University, Princeton, NJ 08540 (United States); Bocarsly, Andrew [Department of Chemistry, Princeton University, Princeton, NJ 08540 (United States)

2005-04-08

A dye doped sol-gel for the sensing of hydrochloric acid in solution and/or gaseous phase is described. The sol-gel is obtained by acidic hydrolysis of tetraethoxysilane (TEOS) and phenyltriethoxysilane (Ph-TriEOS) in the presence of phenol red (PR) and further spin-coating onto glass slides. The sensitive response is based on an increase of the absorption band at 510 nm of phenol red entrapped in the sol-gel casting when exposed to HCl solution or gas, due to protonation of the dye. The detection limit of the sol-gel response to moisturized gaseous HCl is below 12 ppm, and its response to HCl in solution falls in the range of 0.01-6 M. The sol-gel coating has a response time of less than 40 s in steady-state, and life-time of more than a year. Weak acids such as acetic acid, benzoic acid, salicylate acid, citrate acid, and carbonic acid do not interfere the response. The responses in acid solutions are completely reversible. In the gaseous phase, response of HCl appears to be moisture sensitive.

Study of free acidity determinations in aqueous solution

International Nuclear Information System (INIS)

Kergreis, A.

1966-04-01

The object of this work is the study of the principal methods which can be applied to the measurement of 'free' acidity. In the first part, we define the various types of acidity which can exist in aqueous solution; then, after having studied some hydrolysis reactions, we compare the value of the neutralisation pH of the hydrated cation and that of the precipitation of the hydroxide. In the second part we have started to study the determination of the acidity of an aqueous solution. After having rapidly considered the 'total' acidity determination, we deal with the problem of the 'free' acidity titration. We have considered in particular certain methods: extrapolation of the equivalent point, colorimetric titrations with or without a complexing agent, and finally the use of ion-exchange resins with mixed aqueous and solvent solutions. (author) [fr

Principles of interactions in non-aqueous electrolyte solutions

NARCIS (Netherlands)

Lyklema, J.

2013-01-01

In this paper a review is presented on the molecular interactions in non-aqueous media of low dielectric permittivity. Qualitative and quantitative distinctions with aqueous solutions are emphasized. The reviewed themes include dispersion forces, dissociation and association equilibria,

Arsenic (III Adsorption Using Palladium Nanoparticles from Aqueous Solution

Directory of Open Access Journals (Sweden)

Farzaneh Arsiya

2017-07-01

Full Text Available The presence of Arsenic in drinking water is the greatest threat to health effects especially in water. The purpose of this study is application of green palladium nanoparticles for removal of trivalent Arsenic from aqueous solutions and also the impact of some factors such as retention time, pH, concentration of palladium nanoparticles and Arsenic concentrations was studied. The values for Arsenic removal from aqueous solutions were measured by furnace atomic adsorption spectrometry (Conter AA700. In the study, Langmuir and Freundlich isotherm models and pseudo-second order kinetic model were studied. The results of  optimization is shown that 0.5 g of nanoparticles can removed %99.8 of Arsenic with initial concentration of  0.5 g/l, in 5 minutes at pH=4. Langmuir model, Freundlich model (R2=0.94 and pseudo-second order kinetic model (R2=0.99 shown high correlation for removing of Arsenic from aqueous solutions. It was found, palladium nanoparticles can be used as an efficient method to remove Arsenic from aqueous solutions in a short time.

Gas-Microjet Reactive Scattering: Collisions of HCl and DCl with Cool Salty Water.

Science.gov (United States)

Faust, Jennifer A; Sobyra, Thomas B; Nathanson, Gilbert M

2016-02-18

Liquid microjets provide a powerful means to investigate reactions of gases with salty water in vacuum while minimizing gas-vapor collisions. We use this technique to explore the fate of gaseous HCl and DCl molecules impinging on 8 molal LiCl and LiBr solutions at 238 K. The experiments reveal that HCl or DCl evaporate infrequently if they become thermally accommodated at the surface of either solution. In particular, we observe minimal thermal desorption of HCl following HCl collisions and no distinct evidence for rapid, interfacial DCl→HCl exchange following DCl collisions. These results imply that surface thermal motions are not generally strong enough to propel momentarily trapped HCl or DCl back into the gas phase before they ionize and disappear into solution. Instead, only HCl and DCl molecules that scatter directly from the surface escape entry. These recoiling molecules transfer less energy upon collision to LiBr/H2O than to LiCl/H2O, reflecting the heavier mass of Br(-) than of Cl(-) in the interfacial region.

Calculation of the equilibrium pH in a multiple-buffered aqueous solution based on partitioning of proton buffering: a new predictive formula.

Science.gov (United States)

Nguyen, Minhtri K; Kao, Liyo; Kurtz, Ira

2009-06-01

Upon the addition of protons to an aqueous solution containing multiple buffers, the final H+ concentration ([H+]) at equilibrium is determined by the partitioning of added H+ among the various buffer components. In the analysis of acid-base chemistry, the Henderson-Hasselbalch equation and the Stewart strong ion formulation can only describe (rather than predict) the equilibrium pH following a proton load since these formulas calculate the equilibrium pH only when the reactant concentrations at equilibrium(1) 1The term "equilibrium" refers to the steady state proton and reactant concentrations when the buffering of excess protons by the various buffers is complete. are already known. In this regard, it is simpler to directly measure the equilibrium pH rather than measure the equilibrium reactant concentrations to calculate the equilibrium pH. As these formulas cannot predict the final equilibrium [H+] following a proton load to a multiple-buffered aqueous solution, we developed a new quantitative approach for predicting the equilibrium [H+] that is based on the preequilibrium(2)2 The term "preequilibrium" refers to the initial proton and reactant concentrations immediately upon addition of protons and before the buffering of excess protons by the various buffers. concentrations of all buffers in an aqueous solution. The mathematical model used to derive our equation is based on proton transfer buffer equilibria without requiring the incorporation of electroneutrality considerations. The model consists of a quartic polynomial equation that is derived based solely on the partitioning of H+ among the various buffer components. We tested the accuracy of the model using aqueous solutions with various buffers and measured the equilibrium pH values following the addition of HCl. Our results confirmed the accuracy of our new equation (r2 = 1; measured pH vs. predicted pH), indicating that it quantitatively accounts for the underlying acid-base phenomenology.

Calculation of the equilibrium pH in a multiple-buffered aqueous solution based on partitioning of proton buffering: a new predictive formula

Science.gov (United States)

Nguyen, Minhtri K.; Kao, Liyo; Kurtz, Ira

2009-01-01

Upon the addition of protons to an aqueous solution containing multiple buffers, the final H+ concentration ([H+]) at equilibrium is determined by the partitioning of added H+ among the various buffer components. In the analysis of acid-base chemistry, the Henderson-Hasselbalch equation and the Stewart strong ion formulation can only describe (rather than predict) the equilibrium pH following a proton load since these formulas calculate the equilibrium pH only when the reactant concentrations at equilibrium1 1The term “equilibrium” refers to the steady state proton and reactant concentrations when the buffering of excess protons by the various buffers is complete. are already known. In this regard, it is simpler to directly measure the equilibrium pH rather than measure the equilibrium reactant concentrations to calculate the equilibrium pH. As these formulas cannot predict the final equilibrium [H+] following a proton load to a multiple-buffered aqueous solution, we developed a new quantitative approach for predicting the equilibrium [H+] that is based on the preequilibrium22The term “preequilibrium” refers to the initial proton and reactant concentrations immediately upon addition of protons and before the buffering of excess protons by the various buffers. concentrations of all buffers in an aqueous solution. The mathematical model used to derive our equation is based on proton transfer buffer equilibria without requiring the incorporation of electroneutrality considerations. The model consists of a quartic polynomial equation that is derived based solely on the partitioning of H+ among the various buffer components. We tested the accuracy of the model using aqueous solutions with various buffers and measured the equilibrium pH values following the addition of HCl. Our results confirmed the accuracy of our new equation (r2 = 1; measured pH vs. predicted pH), indicating that it quantitatively accounts for the underlying acid-base phenomenology. PMID

Electroerosion of metal in aqueous solution for sample introduction into an inductively coupled plasma mass spectrometer

Energy Technology Data Exchange (ETDEWEB)

Goltz, Douglas E-mail: dgoltz@uwinnipeg.ca; Boileau, Michael; Reinfelds, Gundars

2003-07-18

When high current (1-10 A cm{sup -2}) is applied between two conductive samples (metals) in aqueous solution, electroerosion occurs on the surface as a result of electrolysis and possibly collisions of dissolved ions with the metal surface. The power supply for the electroerosion apparatus in this work was a modified spark source unit. Current could be varied in intervals of 2.5, 5 and 10 A in either half-wave (unipolar) or full-wave (bipolar) output. The electroeroded metal forms a colloidal suspension in aqueous solution with particle sizes of the order of 1-10 {mu}m and possibly larger. The suspension is readily dissolved using a small amount (100 {mu}l) of concentrated acid (HCl or HNO{sub 3}) prior to analysis. Electroerosion of steel and brass in aqueous solution is described both for rapid sample dissolution and as a solid sampling approach for ICP-MS. Some of the electroerosion properties described in this paper include rates of erosion as a function of gap between the conductive samples and solution conductivity. Rates of electroerosion decreased from 120 to 30 {mu}g s{sup -1} as the gap was increased from 2 to 5 mm. Rates of electroerosion also increased significantly from 200 to 1000 {mu}g s{sup -1} as the conductivity of the electroerosion solution increased from 0.01 to 0.05 M NaCl. Interfacing the electroerosion apparatus to an ICP-MS was straight forward, as no special equipment was required. Therefore, the electroerosion apparatus can be used for rapid 'on-line' sample dissolution prior to introduction into an ICP. ICP-MS time profiles of selected metals in stainless steel 308L illustrate the behavior of {sup 52}Cr{sup +}, {sup 55}Mn{sup +} and {sup 60}Ni{sup +} during a typical electroerosion cycle. Aspiration of the colloidal suspension into the ICP did not appear to load the plasma significantly, however, all of the metals produced noisy signals ({+-}10%). A glass concentric nebulizer was used without clogging, so it is likely that the

Reverse osmosis separation of radium from dilute aqueous solutions

International Nuclear Information System (INIS)

Subramanian, K.S.; Sastri, V.S.

1980-01-01

Porous cellulose acetate membranes obtained from Osmonics Inc. were characterized in terms of pure water permeability constant, solute transport parameter, and mass transfer coefficient with aqueous sodium chloride solution as the reference system. Reverse osmosis separation behavior of radium-226 as nitrate, chloride, and sulfate salts was studied. Reverse osmosis method of removing radium-226 from aqueous solutions has been compared with other methods, and it has been shown to be one of the best methods for alleviating radium contamination problems

OPTICAL PROPERTIES OF CARBAMIDE AQUEOUS SOLUTIONS

Directory of Open Access Journals (Sweden)

E. V. Avramenko

2016-03-01

Full Text Available Subject of Research. The paper presents the results of measurements of refractometric properties (refractive index n, its temperature factor dn/dt and the ultraviolet spectral absorption in carbonic acid diamide aqueous solutions (carbamide depending on solid residue mass fraction md = 0-50 % and on temperaturet = 10-70 °C.Method of Research. Laboratory methods ofliquid-phase medium refractometry and ultraviolet spectrophotometry were applied for the research. We carried out computational modeling of electronic states spectrum for the carbonic acid diamide molecule and theoretical calculation of the fundamental electronic absorption of the molecule in the ultraviolet wavelenght region.Main Results. We have established that the solution concentration md has a nonlinear character and may be represented by the quadratic polynomial with the error Δn= ± 0,0005. We have shown the refractive indexdependence on temperature n(t changes in linear fashion att = 10-70 °C.At that, the inclination of lines n(t increases at the increase of md; so, the temperature factor dn/dt may be approximated by the quadratic polynomial. Transmission spectra of solutions in the spectral region λ= 225-760 nm have no special features except for the sharp edge in the short-wavelength region; the fundamental electronic absorptionis responsible for it. We have established that dispersion dependences of the refraction index n(λ;md in aqueous solutions of carbamide at λ= 360-760 nm and at md = 0-50 % may be calculated with the satisfactory error without additional adjustable parameters from the ultraviolet absorption data in terms of the one-dimentional oscillator Lorentz model.PracticalRelevance. Representedmeasurements of carbonic acid diamide aqueous solutions optical properties may be applied for the adjustment and calibration of commercial refractometers at processing lines of the AdBlue reagent manufacture for the selective catalytic reduction (SCR of motor transport

Aqueous solutions/nuclear glasses interactions

International Nuclear Information System (INIS)

Delage, F.; Advocat, T.; Vernaz, E.; Crovisier, J.L.

1991-01-01

Interactions results of the borosilicate glass used in radioactive wastes confinement and aqueous solutions at various temperature and PH show that for the glass components: - the release rate evolution follows an Arrhenius law, - in acid PH, there is a selective dissolution, - in basic PH, there is a stoechiometric dissolution [fr

Study on corrosion of carbon steel in DEA aqueous solutions

Science.gov (United States)

Yang, Jun Han; Xie, Jia Lin; Zhang, Li

2018-02-01

Corrosion of carbon steel in the CO2 capture process using diethanolamine (DEA) aqueous solutions was investigated. The effects of the mass concentrations of DEA, solution temperature and CO2 loading on the corrosion rate of carbon steel were demonstrated. The experimental results provided comprehensive information on the appropriate concentration range of DEA aqueous solutions under which low corrosion of carbon steel can be achieved.

Investigation of ionizing radiation effect on albumin aqueous solutions

International Nuclear Information System (INIS)

Sizikov, A.M.; Adeeva, L.N.; Ogryzkova, I.F.

1986-01-01

Gamma radiation effect on 0.1-0.5%-albumin aqueous solutions has been investigated; variations of viscosity and optical density of solutions at pH medium different values and completeness of protein separation owing to radiation coagulation have been determined. It is shown that due to radiation coagulation it is possible to quantitatively separate albumin from irradiated aqueous solutions. The albumin coagulation is caused by OH radicals the action of which on albumin macromolecules results in destruction of intramolecular bonds and albumin conformation transformations

Predicting accurate absolute binding energies in aqueous solution

DEFF Research Database (Denmark)

Jensen, Jan Halborg

2015-01-01

Recent predictions of absolute binding free energies of host-guest complexes in aqueous solution using electronic structure theory have been encouraging for some systems, while other systems remain problematic. In this paper I summarize some of the many factors that could easily contribute 1-3 kcal......-represented by continuum models. While I focus on binding free energies in aqueous solution the approach also applies (with minor adjustments) to any free energy difference such as conformational or reaction free energy differences or activation free energies in any solvent....

Thermophysical Properties of Aqueous Solutions Used as Secondary Working Fluids

OpenAIRE

Melinder, Åke

2007-01-01

Secondary working fluids (secondary refrigerants, heat transfer fluids, antifreezes, brines) have long been used in various indirect re-frigeration and heat pump systems. Aqueous solutions (water solu-tions) have long been used as single phase (liquid only) secondary working fluids for cooling in supermarkets, ice rinks, heat recovery systems, heat pumps and other applications. However, aqueous solutions are increasingly used also for freezers in supermarkets and other applications in low tem...

A thermodynamic model for aqueous solutions of liquid-like density

Energy Technology Data Exchange (ETDEWEB)

Pitzer, K.S.

1987-06-01

The paper describes a model for the prediction of the thermodynamic properties of multicomponent aqueous solutions and discusses its applications. The model was initially developed for solutions near room temperature, but has been found to be applicable to aqueous systems up to 300/sup 0/C or slightly higher. A liquid-like density and relatively small compressibility are assumed. A typical application is the prediction of the equilibrium between an aqueous phase (brine) and one or more solid phases (minerals). (ACR)

Study of a novel agent for TCA precipitated proteins washing - comprehensive insights into the role of ethanol/HCl on molten globule state by multi-spectroscopic analyses.

Science.gov (United States)

Eddhif, Balkis; Lange, Justin; Guignard, Nadia; Batonneau, Yann; Clarhaut, Jonathan; Papot, Sébastien; Geffroy-Rodier, Claude; Poinot, Pauline

2018-02-20

-precipitated proteins, with the aim to produce high-quality protein extracts which can be directly analyzed by LC-MS. An opening study on standard solutions showed that ethanol/HCl led to reduced losses of proteins compared to usual solvents (i.e. acetone and ethanol). This reagent also enabled a better solubilization of proteins in aqueous buffer that is necessary for their direct trypsin digestion and LC-HRMS analysis. A mechanistic study, performed through several spectroscopic analyses (LC-HRMS, Raman, spectrofluorometry), showed that treatment with ethanol/HCl induced conformational changes of TCA-precipitated proteins. Finally, we compared the efficiency of ethanol/HCl to published protocols for the washing of protein extracts from three different complex samples (i.e. soil, biofilm, and mouse liver). Our results demonstrated that ethanol/HCl is a valuable alternative to previous protein washing methods and, therefore could become a useful tool in mass spectrometry-based proteomics workflows for various applications (e.g. clinical research, chemical biology, environmental metaproteomics…). Copyright © 2017 Elsevier B.V. All rights reserved.

Antimony removal from aqueous solutions using Zirconium hydroxide

International Nuclear Information System (INIS)

Petrescu, D.; Velciu, L.; Bucur, C.

2016-01-01

In this paper it is presented an experimental test for non-radioactive antimony removal from aqueous solutions using zirconium hydroxide powder. Also, it was studied how the temperature and pH influences antimony adsorption onto zirconium hydroxide surface. After the adsorption, solutions were filtered on Cellulose Mixed Ester Membrane with 0.2 μm pore size to remove the zirconium powder and then the aqueous solutions were sent to Inductively Coupled Plasma Optic Emission Spectrometry (ICP-OES) for quantitative analysis of Sb. Zirconium hydroxide powders were examined by optical microscopy. For the solutions that were tested at pH 4.5 and 10.2 the antimony concentration dropped below the detection limit of ICP-OES device, proof of antimony adsorption on zirconium hydroxide. Also, for the other tested solutions which had pH=12 the antimony concentration reduced with 77% and 80%. The temperature had no influence upon adsorption mechanism. (authors)

Status of determining transuranic nuclides speciation in aqueous solution with laser spectrometry

International Nuclear Information System (INIS)

Wang Bo; Liu Dejun; Yao Jun; Chen Xi; Long Haoqi; Zeng Jishu; Su Xiguang; Fan Xianhua

2007-01-01

The knowledge about speciation of transuranic nuclides in aqueous solution is a basis for understanding the chemical and migration behavior of transuranic nuclides in aqueous solution. The speciation of transuranic nuclides with trace concentration is complicated in near neutral aqueous solutions, including change of oxidation state, complexation and colloid generation, etc. The concentrations of transuranium in near neutral aqueous solution usually below the sensitivity range of method such as conventional absorption spectroscopy. The radioactive analysis method has a very low detection limits for radionuclides, however, it wouldn' t allow the direct measurement of the transuranic species. In contrast with these methods, laser spectroscopy is an ideal method with high sensitivity, and non-contact and non-destructive for determining the speciation of transuranic nuclides. This paper summarizes the status and application of LIPAS (Laser-induced Photoacoustic Spectrometry), LIBD (Laser-induced Breakdown Detection) and TRLFS (Time-resolved Laser Fluorescence Spectrometry) to determine the speciation of transuranic nuclides with trace concentration in aqueous solutions. (authors)

Process for the recovery of alkali metal salts from aqueous solutions thereof

International Nuclear Information System (INIS)

Vitner, J.

1984-01-01

In an integrated process for the recovery of alkakli metal phenates and carboxylates from aqueous solutions thereof, the aqueous solution is spray dried and the drying gas stream is contacted with an aqueous alkali metal salt solution which dissolves the particles of the alkali metal salt that were entrained in the drying gas stream. The salt-free inert gas stream is then dried, heated, and returned to the spray dryer

Dissolution of lignin in green urea aqueous solution

Science.gov (United States)

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.

The nonaqueous inhibition of Fe-Co-B-Si amorphous electrodes: An a.c. impedance study in HCl solutions

International Nuclear Information System (INIS)

Habib, K.; Abdullah, A.

1995-01-01

An electrochemical study on Fe-Co-B-Si amorphous electrodes has been conducted. The study was focused on determining the electrochemical impedance spectroscopy (EIS) of four different alloys of Fe-Co-B-Si in various HCl acid solutions. The A.C. impedance and the capacitance of Fe-Co-B-Si, Co-Fe-Ni-B-Si, Co-Fe-Mn-B-Si, and Co-Fe-Ni-Mo-B-Si alloys were obtained in 25, 50, 75 and 100% of HCl acid at room temperature. Electrochemical parameters, i.e., impedance, were found to vary depending on additions of the Ni, Mn, Ni-Mo to Fe-Co-B-Si alloy, the acid concentration, and the nanoscopic surface roughness of the electrodes. Consequently, a correlation between the obtained data is established

LASERS, ACTIVE MEDIA: The aqueous-polyelectrolyte dye solution as an active laser medium

Science.gov (United States)

Akimov, A. I.; Saletskii, A. M.

2000-11-01

The spectral, luminescent, and lasing properties of aqueous solutions of a cationic dye rhodamine 6G with additions of anion polyelectrolytes — polyacrylic and polymethacrylic acids — are studied. It is found that the energy and spectral properties of lasing of these solutions depend on the ratio of concentrations of polyelectrolyte and molecules. It is also found that the lasing parameters of aqueous-polyelectrolyte dye solutions can be controlled by changing the structure of the molecular system. The variation in the structure of aqueous-polyelectrolyte dye solutions of rhodamine 6G resulted in an almost five-fold increase in the lasing efficiency compared to that in aqueous dye solutions.

Bioprospecting of gum kondagogu (Cochlospermum gossypium) for bioremediation of uranium (VI) from aqueous solution and synthetic nuclear power reactor effluents.

Science.gov (United States)

Sashidhar, R B; Selvi, S Kalaignana; Vinod, V T P; Kosuri, Tanuja; Raju, D; Karuna, R

2015-10-01

An ecofriendly green chemistry method using a natural biopolymer, Gum Kondagogu (GK) for the removal of U (VI) from aqueous, simulated nuclear effluents was studied. The adsorption characteristic of GK towards U (VI) from aqueous solution was studied at varied pH, contact time, adsorbent dose, initial U (VI) concentration and temperature using UV-Visible spectroscopy and ICP-MS. Maximum adsorption was seen at pH 4, 0.1% GK with 60 min contact time at room temperature. The GK- U (VI) composite was characterized by FT-IR, zeta potential, TEM and SEM-EDAX. The Langmuir isotherm was found to be 487 mg of U (VI) g(-1) of GK. The adsorption capacity and (%) of U (VI) was found to be 490 ± 5.4 mg g(-1) and 98.5%. Moreover adsorption of U (VI) by GK was not influenced by other cations present in the simulated effluents. The adsorbed U (VI) was efficiently stripped from composite using 1 M HCl. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

Science.gov (United States)

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

γ-Irradiation-induced radiolysis of inulin in aqueous solutions

International Nuclear Information System (INIS)

Tsyba, I.A.; Revina, A.A.; Shostenko, A.G.

1997-01-01

Radiochemical transformations of inulin in aqueous solutions, in air, in the presence of inert gases, helium, nitrogen and in nitrous oxide exposed to various doses of 60 Co γ-irradiation were investigated. It was shown that interactions in inulin with OH radicals are principally responsible for radiolytic decomposition of inulin. The data on radiolysis of more simple model systems were used to make available decomposition spectra of γ-irradiated aerated aqueous solution of inulin. 9 refs., 6 figs

Speciation analysis on Eu(3) in aqueous solution using laser-induced breakdown spectroscopy

International Nuclear Information System (INIS)

Hotokezaka, H.; Tanaka, S.; Nagasaki, S.

2001-01-01

Investigation of the chemical behaviour of lanthanides and actinides in the geosphere is important for the safety assessment of high-level radioactive waste disposal. However, determination of speciation for lanthanides and actinides is difficult, because it is too hard to distinguish between metal ion and colloidal metal in aqueous solution. Laser-induced breakdown spectroscopy (LIBS) can detect both ions and microparticles of metals in aqueous solution, especially, high sensitive to microparticles. In this study, we analysed Eu(III) ion and Eu 2 O 3 particle in aqueous solution by LIBS, and measured the hydrolysis behaviour of Eu(III) in aqueous solution. Furthermore, we tried to detect the plasma emission of Eu(III) ions sorbed on TiO 2 particles, and also tried to observe the adsorption behaviour of Eu(III) ions onto TiO 2 particles in aqueous solution. (authors)

EXTRACTION OF URANYL NITRATE FROM AQUEOUS SOLUTIONS

Science.gov (United States)

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.

[Enhancement effect of double-beam laser processed aqueous solution on ICP emission spectrum].

Science.gov (United States)

Chen, Jin-zhong; Xu, Li-jing; Su, Hong-xin; Li, Xu; Wang, Shu-fang

2015-01-01

In order to change the physical properties of aqueous solution and improve the radiation intensity of the ICP emission spectrum, the effects of different laser power density and irradiation time on the surface tension and viscosity of aqueous solution were investigated by using near infrared laser at 976 nm and CO2 laser at 10. 6 µm to irradiate aqueous solution orthogonally, then the enhancement of ICP spectral intensity with processed solution was discussed. The results showed that the surface tension and viscosity of aqueous solution reduced by 42. 13% and 14. 03% compared with the untreated, and the atomization efficiency increased by 51.26% at the laser power density 0. 265 7 W . cm-2 of 976 nm and 0. 206 9 W . cm-2 of CO2 laser with 40 min irradiation time. With the optimized aqueous solution introduced into the ICP source, the spectral line intensity of sample elements As, Cd, Cr, Hg and Pb was enhanced by 46.29%, 94. 65%, 30. 76%, 33.07% and 94. 58% compared to the untreated aqueous solution, while the signal-to-background ratio increased by 43. 84%, 85. 35%, 28. 71%, 34. 37% and 90. 91%, respectively. Plasma temperature and electron density also increased by 5. 94% and 1. 18% respectively. It is obvious that the method of double-beam laser orthogonal irradiation on solution can reduce the surface tension and viscosity of aqueous solution significantly, and raise the radiationintensity of ICP source, and will provide a better condition for detecting the trace heavy metal elements in water samples.

Refinement of crystal structures of CaHCl, SrHCl, BaHCl, BaHBr, and BaHI

International Nuclear Information System (INIS)

Beck, H.P.; Limmer, A.

1983-01-01

The structures of CaHCl, SrHCl, BaHBr, BaHCl, and BaHI have been refined using single crystal data. The comparison of the parameters with the corresponding data of isotypic fluorohalide compounds gives a valuable insight into the bonding interactions in this structure type. (author)

Refinement of crystal structures of CaHCl, SrHCl, BaHCl, BaHBr, and BaHI

Energy Technology Data Exchange (ETDEWEB)

Beck, H.P.; Limmer, A. (Erlangen-Nuernberg Univ., Erlangen (Germany, F.R.). Inst. fuer Anorganische Chemie)

1983-07-01

The structures of CaHCl, SrHCl, BaHBr, BaHCl, and BaHI have been refined using single crystal data. The comparison of the parameters with the corresponding data of isotypic fluorohalide compounds gives a valuable insight into the bonding interactions in this structure type.

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

Science.gov (United States)

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 Tc2pressure 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 (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.

The interfacial capacitance of an oxidised polycrystalline gold electrode in an aqueous HClO4 electrolyte

International Nuclear Information System (INIS)

Grdeń, M.

2013-01-01

The interfacial capacitance of a polycrystalline gold electrode electrochemically oxidised in an aqueous 0.1 M HClO 4 electrolyte has been investigated by means of the electrochemical impedance spectroscopy. From 1.3 to 3 monolayers of Au atoms were oxidised under constant potential conditions and for various oxidation times. The capacitance of the oxidised layers was analysed as a function of the electrode potential and the extent of the surface oxidation. It was found that the interfacial capacitance decreases upon surface oxidation. The components of the interfacial capacitance of the oxidised layer: the double layer capacitance and the capacitance of the oxidised layer; have been separated. The capacitance of the double layer of the oxidised surface was found to be comparable to the capacitance measured for the metallic surface. - Highlights: • The impedance spectra for thin layers of Au oxides/hydroxides were acquired. • Separate determination of the double layer and the oxide capacitances of oxidised Au • The double layer capacitances of oxidised and non-oxidised Au surfaces are comparable

Self-aggregation of liquids from biomass in aqueous solution

International Nuclear Information System (INIS)

Lomba, Laura; Giner, Beatriz; Zuriaga, Estefanía; Moya, Juana; Lafuente, Carlos

2013-01-01

Highlights: • Aggregation behaviour of liquids from biomass in aqueous solution has been studied. • Standard Gibbs free energies of aggregation have been calculated. • Solubility in water of these compounds has been determined. • Critical aggregation concentration decreases as the solubility in water does. -- Abstract: Aggregation of several chemicals from biomass: furfural derived compounds (furfural, 5-methylfurfural, furfuryl alcohol and tetrahydrofurfuryl alcohol), lactate derived compounds (methyl lactate, ethyl lactate and butyl lactate), acrylate derived compound (methyl acrylate) and levulinate compounds (methyl levulinate, ethyl levulinate and butyl levulinate) in aqueous solution has been characterised at T = 298.15 K through density, ρ, speed of sound, u, and isentropic compressibilities, κ S , measurements. In addition the standard Gibbs free energies of aggregation have been also calculated. Furthermore, in order to deepen insight the behaviour of these chemicals in aqueous solution, the solubility of these compounds has been measured at T = 298.15 K

Polyurethane foam loaded with SDS for the adsorption of cationic dyes from aqueous medium: Multivariate optimization of the loading process.

Science.gov (United States)

Robaina, Nicolle F; Soriano, Silvio; Cassella, Ricardo J

2009-08-15

This paper reports the development of a new procedure for the adsorption of four cationic dyes (Rhodamine B, Methylene Blue, Crystal Violet and Malachite Green) from aqueous medium employing polyurethane foam (PUF) loaded with sodium dodecylsulfate (SDS) as solid phase. PUF loading process was based on the stirring of 200mg PUF cylinders with acidic solutions containing SDS. The conditions for loading were optimized by response surface methodology (RSM) using a Doehlert design with three variables that were SDS and HCl concentrations and stirring time. Results obtained in the optimization process showed that the stirring time is not a relevant parameter in the PUF loading, evidencing that the transport of SDS from solution to PUF surface is fast. On the other hand, both SDS and HCl concentrations were important parameters causing significant variation in the efficiency of the resulting solid phase for the removal of dyes from solution. At optimized conditions, SDS and HCl concentrations were 4.0 x 10(-4) and 0.90 mol L(-1), respectively. The influence of stirring time was evaluated by univariate methodology. A 20 min stirring time was established in order to make the PUF loading process fast and robust without losing efficiency. The procedure was tested for the removal of the four cationic dyes from aqueous solutions and removal efficiencies always better than 90% were achieved for the two concentrations tested (2.0 x 10(-5) and 1.0 x 10(-4)mol L(-1)).

Purification processes of cadmium based quantum dots in aqueous medium: a comparative study

Science.gov (United States)

Petris, Dimitri; Freitas, Denilson V.; dos Santos, Rayany K. V.; Dias, Jéssica M. M.; Navarro, Marcelo

2017-07-01

Three different purification methods for CdTe-MPA quantum dot (QD) were performed in aqueous medium: acid titration (HCl, HClO4, H2SO4 and CH3COOH), non-selective precipitation by addition of acetone and co-precipitation of the QD in the presence of inorganic salts. The QD stock solutions were prepared by an electrochemical method of synthesis, in four different heating times (1 h, 4 h, 8 h and 12 h). After purifications, the QD solids were redispersed in distilled water and analyzed by absorption and emission spectra. The λ abs and λ em of the purified QDs showed similar data observed for QD stock solutions, and the recovery rate varied from 71% to 99%. Co-precipitation method showed some advantages: quantum yield maintenance of the QD redispersed solution, longer period of storage (over 6 months) in solution and in solid state (QD embedded into the KCl crystal lattice). CdSe-MPA and CdS-MPA solutions were also purified by co-precipitation method with KCl, showing good results as observed for CdTe-MPA.

Zeolites as alcohol adsorbents from aqueous solutions

Directory of Open Access Journals (Sweden)

Cekova Blagica

2006-01-01

Full Text Available The potential usage of zeolites as adsorbents for the removal of organic molecules from water was investigated in a series of experiments with aqueous solutions of lower alcohols. This could represent a simple solution to the problem of cleaning up industrial wastewater as well as recovering valuable chemicals at relatively low costs. Adsorption isotherms of the Langmuir type were applied, and calculations showed that the amount of propanol adsorbed on silicalite corresponded to approximately 70% of the pore volume. The adsorption process is simple, and recovery of the more concentrated products is easily done by heat treatment and/or at lowered pressures. Adsorption experiments with aqueous acetone showed that silicalite had approximately the same adsorption capacity for acetone as for n-propanol. Heats of adsorption were determined calorimetrically.

Volumetric properties of itaconic acid aqueous solutions

International Nuclear Information System (INIS)

Nisenbaum, Alexander; Apelblat, Alexander; Manzurola, Emanuel

2012-01-01

Highlights: ► Densities of itaconic acid aqueous solutions in a wide range of concentrations and temperatures. ► The apparent molar volumes and the cubic expansion coefficients. ► The derivatives of isobaric heat capacities with respect to pressure. ► Changes in the structure of water when itaconic acid is dissolved. - Abstract: Densities of itaconic acid aqueous solutions were measured at 5 K intervals from T = (278.15 to 343.15) K. From the determined densities, the apparent molar volumes, the cubic expansion coefficients and the second derivatives of volume with respect to temperature which are interrelated with the derivatives of isobaric heat capacities with respect to pressure were evaluated. These derivatives were qualitatively correlated with the changes in the structure of water when itaconic acid is dissolved in it.

Radiation chemistry of aqueous solutions of acetonitrile and propionitrile

International Nuclear Information System (INIS)

Shushtarian, M.J.

1975-01-01

The radiation chemistry of water and aqueous solutions is a branch of radiation chemistry dealing with chemical changes in water and aqueous solutions induced by high energy radiations. High energy radiations of interest in radiation chemistry are short-wave electromagnetic radiations (X- and γ-rays) and fast charged particles (α- and β-particles, electrons, deuterons and fission fragments). The energy of the particles and photons bringing about chemical reactions in the field of modern radiation chemistry is much higher than that of photons causing photochemical reactions

Radiolysis of Aqueous Toluene Solutions

International Nuclear Information System (INIS)

Christensen, H.C.; Gustafson, R.

1971-04-01

Aqueous toluene solutions have been irradiated with Co γ-rays. In unbuffered solutions the various cresol isomers are formed in a total yield of 0.45, 0.87 and 0.94 molecules/100 eV absorbed energy in argon-, N 2 O- and air - saturated solutions, respectively. The yields are reduced in acid (pH 3) solutions (G 0.14, 0.14 and 0.52, respectively) but the reduction is compensated by the formation of 1,2-di-phenylethane in yields of 0.49 and 1.60 in argon- and N 2 O-saturated solutions, respectively. Benzyl radicals are formed through an acid catalysed water elimination reaction from the initially formed hydroxymethylcyclohexadienyl radical. Phenyltolylmethanes, dimethylbiphenyls and partly reduced dimers are also formed during the radiolysis. Hydrogen is formed in the same yield as the molecular yield, g(H 2 ). Xylene isomers and benzene are formed in trace quantities. The most remarkable effects of the addition of Fe(III) ions to deaerated acid toluene solutions are the formation of benzyl alcohol and benzaldehyde and an increase in the yield of 1,2-diphenylethane

Free radicals generated by radiolysis of aqueous solutions

International Nuclear Information System (INIS)

Schwarz, H.A.

1981-01-01

The free radicals produced in the radiolysis of aqueous solutions span the range of redox potentials from -2.9 to +2.65 volts. The identity and nature of these radicals were discussed. Most of the discussion was results obtained with low LET radiation sources ( 60 Co gamma radiation or electron accelerators). Water radiolysis provides the synthesis of many radicals and radical ions in aqueous solution. The primary radicals, e/sub aq/ - H, OH, are well characterized. The radical population can be made to be 90% pure OH (or O - ) if N 2 O solutions are irradiated, the remaining 10% being H atoms. 55% of the radicals can be converted to H atoms in acid solution or in neutral phosphate solutions(e/sub aq/ - reacts with H 2 PO 4- to produce H). The remaining 45% (OH radicals) are difficult to convert to H by reaction with H 2 , due to the slow rate of the reaction. About 100 atmospheres of H 2 are required to do the conversion in less than 10 - 6 sec. 3 figures, 3 tables. (DP)

Development of Wood Apple Shell (Feronia acidissima Powder Biosorbent and Its Application for the Removal of Cd(II from Aqueous Solution

Directory of Open Access Journals (Sweden)

Ch. Suresh

2014-01-01

Full Text Available A biosorbent was prepared by using wood apple shell (WAS powder and studied its application for the removal of Cd(II from aqueous solution by a batch method. The biosorbent was characterized by infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and elemental analysis. WAS is principally made up of lignin and cellulose, containing functional groups such as alcoholic, ketonic, and carboxylic groups which can be involved in complexation reactions with Cd(II. The effect of experimental parameters like initial pH, contact time, metal ion concentration, and sorbent dose on adsorption was investigated. The optimum pH for biosorption of Cd(II onto WAS was found to be pH 5.0 and the quantitative removal of Cd(II ions was achieved in 30 min. The kinetic study showed that the biosorption process followed the pseudo-second-order rate. Experimental data were analyzed by Langmuir, Freundlich, and Dubinin-Radushkevich isotherm models. Desorption studies were carried out using HCl solution.

Hydrogen-bonded structure in highly concentrated aqueous LiBr solutions

International Nuclear Information System (INIS)

Imano, Masahiro; Kameda, Yasuo; Usuki, Takeshi; Uemura, Osamu

2001-01-01

Neutron diffraction measurements were carried out for H/D isotopically substituted aqueous 10, 25 and 33 mol% LiBr solutions in order to obtain structural information on the intermolecular hydrogen bonds among water molecules in highly concentrated aqueous solutions. Observed scattering cross sections for D 2 O (99.9 % D), 0 H 2 O(35.9 % D) and 0-2 H 2 O(68.0 % D) solutions were combined to deduce partial structure factors, a HH (Q), a XH (Q) and a XX (Q) (X: O, Br and Li). The least squares fitting analysis was applied to the observed partial structure factors to determine the nearest neighbor interatomic distance, root-mean-square amplitude and coordination number. Intermolecular distances, r OH =1.91(1) A, r HH =2.38(1) A and r OO =3.02(1) A, between the nearest neighbor water molecules, were obtained for the 10 mol% LiBr solution. On the other hand, the intermolecular O···H interaction was found to almost disappear in concentrated 25 and 33 mol% LiBr solutions. The result implies that the hydrogen-bonded network is completely broken in highly concentrated aqueous LiBr solutions. (author)

Peroxide coordination of tellurium in aqueous solutions

Energy Technology Data Exchange (ETDEWEB)

Mikhaylov, Alexey A.; Medvedev, Alexander G. [Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Moscow (Russian Federation); The Casali Center of Applied Chemistry, The Institute of Chemistry, The Hebrew University of Jerusalem (Israel); Churakov, Andrei V.; Grishanov, Dmitry A.; Prikhodchenko, Petr V. [Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Moscow (Russian Federation); Lev, Ovadia [The Casali Center of Applied Chemistry, The Institute of Chemistry, The Hebrew University of Jerusalem (Israel)

2016-02-15

Tellurium-peroxo complexes in aqueous solutions have never been reported. In this work, ammonium peroxotellurates (NH{sub 4}){sub 4}Te{sub 2}(μ-OO){sub 2}(μ-O)O{sub 4}(OH){sub 2} (1) and (NH{sub 4}){sub 5}Te{sub 2}(μ-OO){sub 2}(μ-O)O{sub 5}(OH).1.28 H{sub 2}O.0.72 H{sub 2}O{sub 2} (2) were isolated from 5 % hydrogen peroxide aqueous solutions of ammonium tellurate and characterized by single-crystal and powder X-ray diffraction analysis, by Raman spectroscopy and thermal analysis. The crystal structure of 1 comprises ammonium cations and a symmetric binuclear peroxotellurate anion [Te{sub 2}(μ-OO){sub 2}(μ-O)O{sub 4}(OH){sub 2}]{sup 4-}. The structure of 2 consists of an unsymmetrical [Te{sub 2}(μ-OO){sub 2}(μ-O)O{sub 5}(OH)]{sup 5-} anion, ammonium cations, hydrogen peroxide, and water. Peroxotellurate anions in both 1 and 2 contain a binuclear Te{sub 2}(μ-OO){sub 2}(μ-O) fragment with one μ-oxo- and two μ-peroxo bridging groups. {sup 125}Te NMR spectroscopic analysis shows that the peroxo bridged bitellurate anions are the dominant species in solution, with 3-40 %wt H{sub 2}O{sub 2} and for pH values above 9. DFT calculations of the peroxotellurate anion confirm its higher thermodynamic stability compared with those of the oxotellurate analogues. This is the first direct evidence for tellurium-peroxide coordination in any aqueous system and the first report of inorganic tellurium-peroxo complexes. General features common to all reported p-block element peroxides could be discerned by the characterization of aqueous and crystalline peroxotellurates. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

The dissociation mechanism and thermodynamic properties of HCl(aq) in hydrothermal fluids (to 700 °C, 60 kbar) by ab initio molecular dynamics simulations

Science.gov (United States)

Mei, Yuan; Liu, Weihua; Brugger, Joël; Sherman, David M.; Gale, Julian D.

2018-04-01

HCl is one of the most significant volatiles in the Earth's crust. It is well established that chloride activity and acidity (pH) play important roles in controlling the solubility of metals in aqueous hydrothermal fluids. Thus, quantifying the dissociation of HCl in aqueous solutions over a wide range of temperature and pressure is crucial for the understanding and numerical modeling of element mobility in hydrothermal fluids. Here we have conducted ab initio molecular dynamics (MD) simulations to investigate the mechanism of HCl(aq) dissociation and to calculate the thermodynamic properties for the dissociation reaction at 25-700 °C, 1 bar to 60 kbar, i.e. including high temperature and pressure conditions that are geologically important, but difficult to investigate via experiments. Our results predict that HCl(aq) tends to associate with increasing temperature, and dissociate with increasing pressure. In particular, HCl(aq) is highly dissociated at extremely high pressures, even at high temperatures (e.g., 60 kbar, 600-700 °C). At 25 °C, the calculated logKd values (6.79 ± 0.81) are close to the value (7.0) recommended by IUPAC (International Union of Pure and Applied Chemistry) and some previous experimental and theoretical studies (Simonson et al.., 1990; Sulpizi and Sprik, 2008, 2010). The MD simulations indicate full dissociation of HCl at low temperature; in contrast, some experiments were interpreted assuming significant association at high HCl concentrations (≥1 m HCltot) even at room T (logKd ∼0.7; e.g., Ruaya and Seward, 1987; Sretenskaya, 1992; review in Tagirov et al., 1997). This discrepancy is most likely the result of difficulties in the experimental determination of minor (if any) concentration of associated HCl(aq) under ambient conditions, and thus reflects differences in the activity models used for the interpretation of the experiments. With increasing temperature, the discrepancy between our MD results and previous experimental

Cashew Nut Testa Tannin: Assessing its Effects on the Corrosion of Aluminium in HCl

OpenAIRE

Nnaji, Nnaemeka J. N; Obi-Egbedi, Nelson O; Okoye, Chukwuma O. B

2014-01-01

Cashew nut testa tannin (CASTAN) has been found to inhibit the corrosion of aluminium in hydrochloric acid solutions using gravimetric, thermometric and UV/visible spectrophotometric techniques. CASTAN inhibition was by adsorption on aluminium following Temkin isotherm in 0.1 M HCl and Langmuir isotherm in 0.5 M and 2.0 M HCl at 303 Kelvin. Physical adsorption on aluminium has been proposed in studied HCl solutions; therefore, CASTAN is a cathodic inhibitor. Earlier reports (1) showed CASTAN ...

Production of Plutonium Metal from Aqueous Solutions

Energy Technology Data Exchange (ETDEWEB)

Orth, D.A.

2003-01-16

The primary separation of plutonium from irradiated uranium by the Purex solvent extraction process at the Savannah River Plant produces a dilute plutonium solution containing residual fission products and uranium. A cation exchange process is used for concentration and further decontamination of the plutonium, as the first step in the final preparation of metal. This paper discusses the production of plutonium metal from the aqueous solutions.

Water Evaporation from Acoustically Levitated Aqueous Solution Droplets.

Science.gov (United States)

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.

EXTRACTION OF MONOAZO DYES BY HYDROPHILIC EXTRACTANTS FROM AQUEOUS SOLUTIONS

Directory of Open Access Journals (Sweden)

Y. I. Korenman

2012-01-01

Full Text Available The extraction of mono azo dyes E102, E122, E110, E124, E129 from aqueous solutions with hydrophilic solvents (alcohols, esters, ketones and polymers (poly-N-vinylamides, polyethylene glycol was studied. The main regularities of extraction are established. The distribution coefficients and degree of extraction of dyes was estimate. The influence of the nature of solvents and polymers on the extraction of dyes from aqueous solutions are established.

Chemical behaviour of plutonium in aqueous chloride solutions

International Nuclear Information System (INIS)

Bueppelmann, K.; Kim, J.I.

1988-06-01

The chemical behaviour of Plutonium has been investigated in concentrated NaCl solutions in the neutral pH range. The α-radiation induced radiolysis reactions oxidize the Cl - -ion to Cl 2 , HClO, ClO - and other species, which produce a strongly oxidizing medium. Under these conditions the Pu ions of lower oxidation states are readily oxidized to Pu(VI), which then undergo depending on the pH of the solution, various chemical reactions to produce PuO 2 Cl n , PuO 2 (ClO) m or PuO 2 (OH) x species. In addition to primary radiolysis reactions taking place in NaCl solutions, the reactions leading to the PuO 2 (Cl) n and PuO 2 (ClO) m species have been characterized and quantified systematically by spectroscopic and thermodynamic evaluation. The redox and complexation reactions of Pu ions under varying NaCl concentration, specific α-activity and pH are discussed. (orig.) [de

Luminescence properties of tetravalent uranium in aqueous solution

International Nuclear Information System (INIS)

Kirishima, A.; Kimura, T.; Nagaishi, R.; Tochiyama, O.

2004-01-01

The luminescence spectra of U 4+ in aqueous solutions were observed in the UV-VIS region at ambient and liquid nitrogen temperatures. The excitation spectrum indicates that the luminescence is arising from the deexcitation of a 5f electron at the 1 S 0 level and no other emissions of U 4+ in aqueous solutions were detected for other f-f transitions. All the luminescence peaks were assigned to the transitions from 1 S 0 to lower 5f levels. To estimate the luminescence lifetime, luminescence decay curves were measured using time-resolved laser-induced fluorescence spectroscopy. At room temperature, the decay curve indicated that the lifetime was shorter than 20 ns. On the other hand, the frozen sample of U 4+ in aqueous solution at liquid nitrogen temperature showed the same emission spectrum as at room temperature and its lifetime was 149 ns in H 2 O system and 198 ns in D 2 O system. The longer lifetime at liquid nitrogen temperature made it possible to measure the spectrum of U 4+ at the concentration as low as 10 -6 M. The difference in the anion species (ClO 4 - , Cl - , SO 4 2- ) affected the structure of the emission spectrum to some extent. (orig.)

Recoil halogen reactions in liquid and frozen aqueous solutions of biomolecules

International Nuclear Information System (INIS)

Arsenault, L.J.; Blotcky, A.J.; Firouzbakht, M.L.; Rack, E.P.; Nebraska Univ., Omaha

1982-01-01

Reactions of recoil 38 Cl, 80 Br and 128 I have been studied in crystalline systems of 5-halouracil, 5-halo-2'-deoxyuridine and 5-halouridine as well as liquid and frozen aqueous solutions of these halogenated biomolecules. In all systems expect crystalline 5-iuodouracil the major product was the radio-labelled halide ion. There was no evidence for other halogen inorganic species. The major labelled organic product was the parent molecule. A recoil atom tracer technique was developed to acquire site information of the biomolecule solutes in the liquid and frozen aqueous systems. For all liquid and frozen aqueous systems, the halogenated biomolecules tended to aggregate. For liquid systems, the tendency for aggregation diminished as the solute concentration approached zero, where the probable state of the solute approached a monomolecular dispersion. Unlike the liquid state, the frozen ice lattice demonstated a ''caging effect'' for the solute aggregates which resulted in constant product yields over the whole concentration range. (orig.)

γ-radiation induced tetracycline removal in an aqueous solution

International Nuclear Information System (INIS)

Zhou Fei; Guo Zhaobing; Zhang Chaozhi; Lin Mingyue; Wu Menglong; Zhao Yongfu

2012-01-01

Degradation effect of tetracycline (TC) by γ-radiation was investigated in an aqueous solution. The effects of initial concentrations of TC, pH values, combining with H 2 O 2 or CH 3 OH on degradation of TC were studied. Results showed that TC can be effectively degradated by γ-irradiation in an aqueous solution. Degradation of TC could be remarkably improved both in acid solution and alkaline solution, especially when pH value was 9.0. In addition, H 2 O 2 could gently promote degradation of TC induced by γ-radiation. While, CH 3 OH markedly restrained degradation of TC induced by γ-radiation. The degradation mechanism of TC was supposed by results of quantum chemical calculations and LC-MS. Results proved that degradation of TC induced by γ-radiation was mainly ascribed to · OH oxidation. (authors)

Heavy metal removal from aqueous solutions by sorption using ...

African Journals Online (AJOL)

Heavy metal removal from aqueous solutions by sorption using natural clays from Burkina Faso. ... The high alkaline pH in one of the samples is attributable to the presence of ... The point of zero charge (pHpzc) values of the clays, as determined by ... significant contributions to the removal of metal ions in aqueous systems.

Synthesis of Novel Polymeric Resins by Gamma Irradiation for Separation of In(III) ions from Cd(II) in Aqueous Media

International Nuclear Information System (INIS)

Massoud, A.; Abou El-Nour, F.; Killa, H.

2012-01-01

In this work, Zn(II)polymethacrylates and poly(acrylamide-acrylic acid) were prepared by gamma irradiation polymerization technique of the corresponding monomer at 30 kGy. The polymeric resins were mixed with Indium ions to determine its capacity in aqueous solutions using batch experiment. The adsorption efficiency of obtained polymeric resins toward In(III) and Cd(II) in different experimental conditions was established. Batch and column methods were applied for separation of indium and cadmium. The effects of various eluants such as H 2 SO 4 , NH 4 NO 3 , HNO 3 and HCl on the recovery of both metal ions were studied. The polymeric resins may be regenerated using 3M HCl solutions.

Complex chemistry of Np(V) in aqueous solutions

International Nuclear Information System (INIS)

Inoue, Yasushi

1989-01-01

Despite the importance of Np(V) in both the nuclear chemical engineering and the actinoid chemistry, little work has been performed on the complex chemistry of Np(V) in aqueous solutions, since Np(V) reacts less readily with various ligands. The author has directed his effort to understand the chemical behavior of Np(V) in aqueous solutions, especially the determination of the stability constants of Np(V) complexes with various ligands. A part of the results obtained so far is presented in the following order. (1) The synergistic extraction of Np(V) as a method for studying the complex chemistry of Np(V): TTA-MTOA(methyltrioctylammonium chloride), TTA-phen and TTA-TOPO. (2) The determination of the stability constants of Np(V) complexes with 22 organic- and 5 inorganic ligands by means of the solvent extraction. (3) The distribution of the chemical species of Np(V) in solutions under various conditions

Flotation separation of hafnium(IV) from aqueous solutions

International Nuclear Information System (INIS)

Downey, D.M.; Narick, C.N.; Cohen, T.A.

1985-01-01

A simple, rapid method for the separation of hafnium from aqueous solutions was investigated using sup(175+181)Hf tracer. Cationic hafnium complex ions were floated from dilute acid solutions with sodium lauryl sulfate (SLS) and anionic hafnium complexes were floated from basic and oxalic acid solutions with hexadecyltrimethyl ammonium bromide (HTMAB). The conditions necessary for quantitative recovery of the metal and mechanisms of flotation are described. (author)

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

Science.gov (United States)

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.

Radiolysis of Aqueous Toluene Solutions

Energy Technology Data Exchange (ETDEWEB)

Christensen, H C; Gustafson, R

1971-04-15

Aqueous toluene solutions have been irradiated with Co gamma-rays. In unbuffered solutions the various cresol isomers are formed in a total yield of 0.45, 0.87 and 0.94 molecules/100 eV absorbed energy in argon-, N{sub 2}O- and air - saturated solutions, respectively. The yields are reduced in acid (pH 3) solutions (G = 0.14, 0.14 and 0.52, respectively) but the reduction is compensated by the formation of 1,2-di-phenylethane in yields of 0.49 and 1.60 in argon- and N{sub 2}O-saturated solutions, respectively. Benzyl radicals are formed through an acid catalysed water elimination reaction from the initially formed hydroxymethylcyclohexadienyl radical. Phenyltolylmethanes, dimethylbiphenyls and partly reduced dimers are also formed during the radiolysis. Hydrogen is formed in the same yield as the molecular yield, g(H{sub 2}). Xylene isomers and benzene are formed in trace quantities. The most remarkable effects of the addition of Fe(III) ions to deaerated acid toluene solutions are the formation of benzyl alcohol and benzaldehyde and an increase in the yield of 1,2-diphenylethane

Effects of Radiosterilization on Sealed Aqueous Solutions

International Nuclear Information System (INIS)

Pandula, E.L.; Farkas, E.; Rácz, I.

1967-01-01

For aqueous solutions sensitive to heat,and in connection with the use of plastic ampoules, the need for applying radiosterilization is growing. Studying the possibilities of radiosterilization, experiments were made with the following: 0.1% atropine, 1.0% morphine, and 2% lidocain in aqueous solutions. The aim of the work was to establish whether the active ingredients of the injections suffer decomposition or not, to study the factors influencing the degradation and, furthermore, to make attempts to prevent decomposition. The samples were irradiated by 420 Ci 60 Co γ-radiation source. The applied doses were 1 to 2.5 Mrad, with a 10 4 to 2.5 x 10 5 rad/h dose intensity. After irradiation the change in colour, pH-value, concentration and UV-spectra were studied. Changes of the last three types were found. Studying the factors influencing decomposition it has been found that the degree of degradation was increased by the increase of radiation dose, increase of concentration, decrease of dose intensity, and increase of oxygen content in the atmosphere over the solution. Attempts were made to prevent degradation. Solutions were prepared with sulphite, ascorbic acid, and AET, and some measure of success was achieved, especially with the sulphite addition. (author)

Photochemical properties of Ysub(t) base in aqueous solution

International Nuclear Information System (INIS)

Paszyc, S.; Rafalska, M.

1979-01-01

Photoreactivity of Ysub(t) base (I) has been studied in aqueous solution (pH-6) saturated with oxygen. Two photoproducts (II,III), resulting from irradiation at lambda = 253.7 nm and lambda >= 290 nm were isolated and their structures determined. The quantum yield for Ysub(t) base disappearance (rho dis) is 0.002 (lambda = 313 nm). It was shown that dye- sensitised photo-oxidation of Ysub(t) base in aqueous solution occurs according to a Type I mechanism as well as with participation of singlet state oxygen. Quantum yields, fluorescence decay times and phosphorescence of Ysub(t) base have also been determined. (author)

Aqueous solutions of ionic liquids: microscopic assembly

NARCIS (Netherlands)

Vicent-Luna, J.M.; Dubbeldam, D.; Gómez-Álvarez, P.; Calero, S.

2016-01-01

Aqueous solutions of ionic liquids are of special interest, due to the distinctive properties of ionic liquids, in particular, their amphiphilic character. A better understanding of the structure-property relationships of such systems is hence desirable. One of the crucial molecular-level

Thermodynamic modeling of ternary and quaternary (liquid + liquid) systems containing water, FeCl3, HCl and diisopropyl ether

International Nuclear Information System (INIS)

Milosevic, Miran; Hendriks, Ilse; Smits, Ralph E.R.; Schuur, Boelo; Haan, André B. de

2013-01-01

Highlights: • Literature data from various sources was validated experimentally. • Ternary and quaternary (liquid + liquid) systems were successfully described with the NRTL model. • Some deflection at higher HCl concentrations between model and data. • Additional data verification proved correctness of the literature data. -- Abstract: Liquid–liquid extraction using ethers as solvents is a potentially energy saving alternative for the concentration of aqueous ferric chloride solutions. Adequate thermodynamic models that describe the behavior of the resulting quaternary systems (FeCl 3 , ether, acid and water) are not available in the literature. In this paper, the development of an equilibrium description applying the NRTL-model is presented, including experimental validation and fitting of the NRTL-parameters on the validated data. Equilibrium experiments were performed for the ternary systems (water + HCl + DiPE) and (water + FeCl 3 + DiPE) and the obtained data is in good agreement with the results from Maljkovic et al.[37] and Cambell et al.[39]. Experimental data of the quaternary system is taken from Maljkovic et al.[37]. The obtained binary interaction parameters to describe the (liquid + liquid) quaternary system (water + FeCl 3 + HCl + DiPE) and the constituting ternaries by the NRTL model are presented. Model predictions are in good agreement with the experimental data

Surface tension and related thermodynamic quantities of aqueous electrolyte solutions

CERN Document Server

Matubayasi, Norihiro

2013-01-01

Surface tension provides a thermodynamic avenue for analyzing systems in equilibrium and formulating phenomenological explanations for the behavior of constituent molecules in the surface region. While there are extensive experimental observations and established ideas regarding desorption of ions from the surfaces of aqueous salt solutions, a more successful discussion of the theory has recently emerged, which allows the quantitative calculation of the distribution of ions in the surface region. Surface Tension and Related Thermodynamic Quantities of Aqueous Electrolyte Solutions provides a d

Adsorption of lead from aqueous solutions by poly (methyl methacrylate)

International Nuclear Information System (INIS)

Din, M.; Hussain, R.

1992-01-01

The adsorption capability of commercially manufactured poly (methyl methacrylate) for lead in aqueous medium has been investigated. Percent adsorption and distribution coefficient values have been determined in relation to the shaking time, amount of adsorbent, pH effects and concentration of lead in the solution. The experimental results are compatible with Freundlich type of adsorption behavior. It is discernible from the experimental results that poly (methyl methacrylate) can be used for the removal of lead from slightly acidic aqueous solutions. (author)

Removal of dexamethasone from aqueous solution and hospital wastewater by electrocoagulation

International Nuclear Information System (INIS)

Arsand, Daniel R.; Kümmerer, Klaus; Martins, Ayrton F.

2013-01-01

This study is concerned with the removal of the anti-inflammatory dexamethasone from aqueous solution and hospital wastewater by electrocoagulation. The variation of the toxicity during the electrocoagulation was also studied through experiments that were designed and optimized by means of response surface methodology. The coagulation efficiency was evaluated by measuring the dexamethasone concentration by high performance liquid chromatography coupled to a diode array detector. In addition, variation was evaluated through a Vibrio fischeri test. The results showed an increase in the removal of dexamethasone (up to 38.1%) with a rise of the current applied and a decrease of the inter-electrode distance, in aqueous solutions. The application to hospital effluent showed similar results for the removal of dexamethasone. The main effect of the electrocoagulation was that it removed colloids and reduced the organic load of the hospital wastewater. Regarding the current applied, the calculated energy efficiency was 100%. Without pH adjustment of the aqueous solution or hospital wastewater, the residual aluminum concentration always remained lower than 10 mg L −1 , and, with adjustment (to pH 6.5), lower than 0.30 mg L −1 , at the final stage. No toxicity variation was observed during the electrocoagulation process in aqueous solution, either in the presence or absence of dexamethasone. - Highlights: ► Removal of DEX and organic load from aqueous solution and hospital wastewater by EC ► Evaluation of the toxicity during the removal of DEX by EC ► Suggestion of the EC process as a pretreatment for subsequent processes

Removal of dexamethasone from aqueous solution and hospital wastewater by electrocoagulation

Energy Technology Data Exchange (ETDEWEB)

Arsand, Daniel R., E-mail: danielarsand@pelotas.ifsul.edu.br [Chemistry Department, Federal University of Santa Maria, RS (Brazil); Kümmerer, Klaus, E-mail: klaus.kuemmerer@leuphana.de [Institute for Environmental Chemistry, Leuphana University Lüneburg (Germany); Martins, Ayrton F., E-mail: martins@quimica.ufsm.br [Chemistry Department, Federal University of Santa Maria, RS (Brazil)

2013-01-15

This study is concerned with the removal of the anti-inflammatory dexamethasone from aqueous solution and hospital wastewater by electrocoagulation. The variation of the toxicity during the electrocoagulation was also studied through experiments that were designed and optimized by means of response surface methodology. The coagulation efficiency was evaluated by measuring the dexamethasone concentration by high performance liquid chromatography coupled to a diode array detector. In addition, variation was evaluated through a Vibrio fischeri test. The results showed an increase in the removal of dexamethasone (up to 38.1%) with a rise of the current applied and a decrease of the inter-electrode distance, in aqueous solutions. The application to hospital effluent showed similar results for the removal of dexamethasone. The main effect of the electrocoagulation was that it removed colloids and reduced the organic load of the hospital wastewater. Regarding the current applied, the calculated energy efficiency was 100%. Without pH adjustment of the aqueous solution or hospital wastewater, the residual aluminum concentration always remained lower than 10 mg L{sup −1}, and, with adjustment (to pH 6.5), lower than 0.30 mg L{sup −1}, at the final stage. No toxicity variation was observed during the electrocoagulation process in aqueous solution, either in the presence or absence of dexamethasone. - Highlights: ► Removal of DEX and organic load from aqueous solution and hospital wastewater by EC ► Evaluation of the toxicity during the removal of DEX by EC ► Suggestion of the EC process as a pretreatment for subsequent processes.

Flotation separation of hafnium(IV) from aqueous solutions

Energy Technology Data Exchange (ETDEWEB)

Downey, D.M.; Narick, C.N.; Cohen, T.A.

1985-09-01

A simple, rapid method for the separation of hafnium from aqueous solutions was investigated using sup(175 + 181)Hf tracer. Cationic hafnium complex ions were floated from dilute acid solutions with sodium lauryl sulfate (SLS) and anionic hafnium complexes were floated from basic and oxalic acid solutions with hexadecyltrimethyl ammonium bromide (HTMAB). The conditions necessary for quantitative recovery of the metal and mechanisms of flotation are described. (author). 21 refs.; 5 figs.

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

Energy Technology Data Exchange (ETDEWEB)

Cochrane, T. T., E-mail: agteca@hotmail.com [AGTECA S.A., 230 Oceanbeach Road, Mount Maunganui, Tauranga 3116 (New Zealand); Cochrane, T. A., E-mail: tom.cochrane@canterbury.ac.nz [Department of Civil and Natural Resources Engineering, University of Canterbury, Private Bag 4800, Christchurch 8140 (New Zealand)

2016-01-15

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 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, “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

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

International Nuclear Information System (INIS)

Cochrane, T. T.; Cochrane, T. A.

2016-01-01

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 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, “N 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 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 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 f using recorded

Spinning of Fibers from Aqueous Solutions

Science.gov (United States)

2003-08-01

recombinant silk product BioSteel . Publications, patents and presentations 1. Arcidiacono, S., et al., Purification and characterization of recombinant...ABSTRACT Previous funding supporting this research focused primarily on development of the aqueous-based method for processing silk into spin solutions. Much...of this effort consisted of production of recombinant silk protein in bacterial and yeast expression systems. In spite of the small quantities

Investigation of strontium sorption on Kula volcanites treated with HCl

International Nuclear Information System (INIS)

Kuetahyali, C.; Cetinkaya, B.; Acar, M. B.; Isik, N. O.; Cireli, I.

2009-01-01

In planning the disposal of radioactive waste in a deep geologic repository, consideration must be given to the ways in which radionuclides might leave the repository and migrate through the geosphere. In performance assessment studies the uptake of the radioactive elements by rock formations play an important role in retarding their aqueous phase migration. Sorption studies of radionuclides have been conducted to obtain data on the distribution coefficient (K d ) that is as an input parameter in the performance assessment of the geological disposal of radioactive wastes. In many studies, the sorption experiments employed natural soils and rocks as sorbents. Adsorption experiments were studied in a batch adsorption system using Sr(NO 3 ) 2 (Merck) solution. Strontium sorption on Kula Volcanites treated with HCl was investigated. Central Composite Design Method was used in the experiments. Sr adsorption was studied as a function of pH, contact time, concentration of adsorbate, and temperature.

In Situ Structural Characterization of Ferric Iron Dimers in Aqueous Solutions

DEFF Research Database (Denmark)

Zhu, Mengqiang; Puls, Brendan W.; Frandsen, Cathrine

2013-01-01

The structure of ferric iron (Fe3+) dimers in aqueous solutions has long been debated. In this work, we have determined the dimer structure in situ in aqueous solutions using extended X-ray absorption fine structure (EXAFS) spectroscopy. An Fe K-edge EXAFS analysis of 0.2 M ferric nitrate solutions...... at pH 1.28–1.81 identified a Fe–Fe distance at ∼3.6 Å, strongly indicating that the dimers take the μ-oxo form. The EXAFS analysis also indicates two short Fe–O bonds at ∼1.80 Å and ten long Fe–O bonds at ∼2.08 Å, consistent with the μ-oxo dimer structure. The scattering from the Fe–Fe paths interferes...... confirmed by Mössbauer analyses of analogous quick frozen solutions. This work also explores the electronic structure and the relative stability of the μ-oxo dimer in a comparison to the dihydroxo dimer using density function theory (DFT) calculations. The identification of such dimers in aqueous solutions...

Thermophysical property characterization of aqueous amino acid salt solution containing serine

International Nuclear Information System (INIS)

Navarro, Shanille S.; Leron, Rhoda B.; Soriano, Allan N.; Li, Meng-Hui

2014-01-01

Highlights: • Thermophysical properties of aqueous potassium and sodium salt solutions of serine were studied. • Density, viscosity, refractive index and electrolytic conductivity of the solution were measured. • The concentrations of amino acid salt ranges from x 1 = 0.009 to 0.07. • The temperature range studied was (298.15 to 343.15) K. • The measured data were represented satisfactorily by using the applied correlations. - Abstract: Thermophysical property characterization of aqueous potassium and sodium salt solutions containing serine was conducted in this study; specifically the system’s density, refractive index, electrical conductivity, and viscosity. Measurements were obtained over a temperature range of (298.15 to 343.15) K and at normal atmospheric pressure. Composition range from x 1 = 0.009 to 0.07 for aqueous potassium and sodium salt solutions containing serine was used. The sensitivity of the system’s thermophysical properties on temperature and composition variation were discussed and correlated based on the equations proposed for room temperature ionic liquids. The density, viscosity, and refractive index measurements of the aqueous systems were found to decrease as the temperature increases at fixed concentration and the values increase as the salt concentration increases (water composition decreases) at fixed temperature. Whereas, a different trend was observed for the electrical conductivity data; at fixed concentration, the conductivity values increase as the temperature increases and at fixed temperature, its value generally increases as the salt concentration increases but only to a certain level (specific concentration) wherein the conductivity of the solution starts to decrease when the concentration of the salt is further increased. Calculation results show that the applied models were satisfactory in representing the measured properties in the aqueous amino acid salt solution containing serine

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

Science.gov (United States)

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.

Pulse radiolysis of anthraquinone dye aqueous solution

International Nuclear Information System (INIS)

Perkowski, J.; Gebicki, J.L.; Lubis, R.; Mayer, J.

1988-01-01

Pulse radiolysis of argon flushed aqueous solutions of 10 -5 -10 -4 mol dm -3 anthraquinone dye (C.I. Acid Blue 62) gives rise to the transients originated from the reactions of e - aq , OH and H. The rate constants of these reactions are determined. (author)

Corrosion Resistance Behavior of Single-Layer Cathodic Arc PVD Nitride-Base Coatings in 1M HCl and 3.5 pct NaCl Solutions

Science.gov (United States)

Adesina, Akeem Yusuf; Gasem, Zuhair M.; Madhan Kumar, Arumugam

2017-04-01

The electrochemical behavior of single-layer TiN, CrN, CrAlN, and TiAlN coatings on 304 stainless steel substrate, deposited using state-of-the-art and industrial size cathodic arc PVD machine, were evaluated in 1M HCl and 3.5 pct NaCl solutions. The corrosion behavior of the blank and coated substrates was analyzed by electrochemical impedance spectroscopy (EIS), linear polarization resistance, and potentiodynamic polarization. Bond-coat layers of pure-Ti, pure-Cr, alloyed-CrAl, and alloyed-TiAl for TiN, CrN, CrAlN, and TiAlN coatings were, respectively, first deposited for improved coating adhesion before the actual coating. The average coating thickness was about 1.80 µm. Results showed that the corrosion potentials ( E corr) of the coated substrates were shifted to more noble values which indicated improvement of the coated substrate resistance to corrosion susceptibility. The corrosion current densities were lower for all coated substrates as compared to the blank substrate. Similarly, EIS parameters showed that these coatings possessed improved resistance to defects and pores in similar solution compared to the same nitride coatings developed by magnetron sputtering. The charge transfer resistance ( R ct) can be ranked in the following order: TiAlN > CrN > TiN > CrAlN in both media except in NaCl solution where R ct of TiN is lowest. While the pore resistance ( R po) followed the order: CrAlN > CrN > TiAlN > TiN in HCl solution and TiAlN > CrN > CrAlN > TiN in NaCl solution. It is found that TiAlN coating has the highest protective efficiencies of 79 and 99 pct in 1M HCl and 3.5 pct NaCl, respectively. SEM analysis of the corroded substrates in both media was also presented.

Separation of Co2+ present in aqueous solution on calcium carbonate

International Nuclear Information System (INIS)

Garcia A, E.; Granados C, F.

2008-01-01

The CaCO 3 was synthesized by precipitation method and characterized using SEM, EDS, TGA and IR. It was studied the adsorption behavior of Co 2+ present in aqueous solution on the synthesized material by experiments batch type at room temperature. Was found that removal of cobalt ions was greater than 40% indicating that this material can be used to remove Co 2+ present in aqueous solution. (Author)

Uranium in aqueous solutions by colorimetry

International Nuclear Information System (INIS)

Anon.

1981-01-01

The method covers the quantitative determination of uranium in known volumes of aqueous solutions that contain radioactive nuclides. These solutions arise from processing of irradiated nuclear fuel and from laboratory studies on irradiated uranium. The method is applicable to solutions containing a minimum of 30 μg of uranium per sample although as little as 0.5 μg can be detected but with lower precision. Highest precision is obtained with 50 to 75 μg of uranium in the test sample. Dilutions must be made at concentrations above 750 μg/ml. The method includes a discussion of photometers and photometric practice, apparatus, reagents, cell matching, preparation of standard curves, calibration by the method of internal standards, procedure, calculation, and precision

Isomers of Poly Aminophenol: Chemical Synthesis, Characterization, and Its Corrosion Protection Aspect on Mild Steel in 1 M HCl

Directory of Open Access Journals (Sweden)

G. Thenmozhi

2014-01-01

Full Text Available The oxidative chemical polymerizations of three isomers of aminophenol, ortho, meta, and para (PoAP, PmAP, and PpAP, were performed in aqueous HCl using ammonium persulfate as an oxidant at 0–3°C. The synthesized polymers were characterized by employing elemental analysis, GPC, UV-VIS-NIR, FT-IR, XRD, and TGA. The corrosion inhibition effect of these three polymers on mild steel in 1 M HCl solution was studied by using electrochemical techniques such as potentiodynamic polarization and electrochemical impedance spectroscopy. These measurements reveal that the inhibition efficiency obtained by these polymers increased by increasing their concentration. The inhibition efficiency follows the order PpAP > PoAP > PmAP. The results further revealed that PpAP at a concentration of 250 mg/L furnishes maximum inhibition efficiency (96.5%. Polarization studies indicated that these three polymers act as the mixed type corrosion inhibitors.

Adsorption of Polycyclic Aromatic Hydrocarbons (PAHS from Aqueous Solutions on Different Sorbents

Directory of Open Access Journals (Sweden)

Smol Marzena

2014-12-01

Full Text Available This paper presents the results of the possibility and effectiveness of PAHs removal from a model aqueous solution, during the sorption on the selected sorbents. Six PAHs (naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene listed by EPA for the analysis in the environmental samples were determined. Model aqueous solution was prepared with RESTEK 610 mix PAHs standard. After the sorption process, decrease in the concentration of individual hydrocarbons was observed. The removal percentage was dependent on the type of sorbent (quartz sand, mineral sorbent, activated carbon. The highest efficiency (98.1% was observed for activated carbon.. The results shows that the sorption processes can be used in aqueous solutions treatment procedures.

Application of Activated Carbon for Removal of Arsenic Ions from Aqueous Solutions

Directory of Open Access Journals (Sweden)

R. Ansari

2007-01-01

Full Text Available The activated carbon (AC was used for removal of As(III and As(V ions from aqueous solutions. Sorption experiments were conducted using both batch and column systems. The effect of some important parameters on sorption of these by AC was studied. It was found that among the different factors affecting sorption capacity and efficiency in removal of arsenic from aqueous solutions, the effect of pH and the oxidation state were the most prominent. The optimum pH values for removal of As(III and As(V from aqueous solutions using AC was found 12 and 3 respectively. Impregnation of AC with sulphur contain organic dyes, it is possible to improve As(III uptake considerably.

Assembly of DNA Architectures in a Non-Aqueous Solution

Directory of Open Access Journals (Sweden)

Thomas J. Proctor

2012-08-01

Full Text Available In the present work, the procedures for the creation of self-assembled DNA nanostructures in aqueous and non-aqueous media are described. DNA-Surfactant complex formation renders the DNA soluble in organic solvents offering an exciting way to bridge the transition of DNA origami materials electronics applications. The DNA retains its structural features, and these unique geometries provide an interesting candidate for future electronics and nanofabrication applications with potential for new properties. The DNA architectures were first assembled under aqueous conditions, and then characterized in solution (using circular dichroism (CD spectroscopy and on the surface (using atomic force microscopy (AFM. Following aqueous assembly, the DNA nanostructures were transitioned to a non-aqueous environment, where butanol was chosen for optical compatibility and thermal properties. The retention of DNA hierarchical structure and thermal stability in non-aqueous conditions were confirmed via CD spectroscopy. The formation and characterization of these higher order DNA-surfactant complexes is described in this paper.

Molybdenum: the element and aqueous solution chemistry

International Nuclear Information System (INIS)

Sykes, A.G.

1987-01-01

This chapter on the chemistry of the coordination compounds of molybdenum concentrates on the element itself, its recovery from ores and its use in the manufacture of steels. Most of the chapter is devoted to the aqueous solution chemistry of molybdenum in oxidation states II, III and IV. (UK)

Synthesis of sub-millimeter calcite from aqueous solution

Science.gov (United States)

Reimi, M. A.; Morrison, J. M.; Burns, P. C.

2011-12-01

A novel aqueous synthesis that leads to the formation of calcite (CaCO3) crystals, up to 500μm in diameter, will be used to facilitate the study of contaminant transport in aqueous environmental systems. Existing processes tend to be complicated and often yield nanometer-sized or amorphous CaCO3. The synthesis method presented here, which involves slow mixing of concentrated solutions of CaCl2 ¬and (NH4)2CO3, produces single crystals of rhombohedral calcite in 2 to 4 days. Variations on the experimental method, including changes in pH and solution concentration, were explored to optimize the synthesis. Scanning Electron Microscope images show the differences in size and purity observed when the crystals are grown at pH values ranging from 2 to 6. The crystals grown from solutions of pH 2 were large (up to 500 micrometers in diameter) with minimal polycrystalline calcium carbonate, while crystals grown from solutions with pH values beyond 4 were smaller (up to 100 micrometers in diameter) with significant polycrystalline calcium carbonate. The synthesis method, materials characterization, and use in future actinide contaminant studies will be discussed.

Benzimidazole and its derivatives as corrosion inhibitors for mild steel in 1M HCl solution

International Nuclear Information System (INIS)

Aljourani, J.; Raeissi, K.; Golozar, M.A.

2009-01-01

In this paper, the inhibition ability of benzimidazole and its derivatives against the corrosion of mild steel in 1M HCl solution was studied. The change of impedance parameters observed by variation of inhibitors concentration within the range of 50-250 ppm was an indication of their adsorption. The thermodynamic adsorption parameters proposed that these inhibitors retard both cathodic and anodic processes through physical adsorption and blocking the active corrosion sites. The adsorption of these compounds obeyed the Langmuir's adsorption isotherm. The inhibition efficiency was increased with inhibitor concentration in the order of 2-mercaptobenzimidazole > 2-methylbenzimidazole > benzimidazole, which is in accordance with the variation of apparent activation energy of corrosion.

Measuring the density and viscosity of H2S-loaded aqueous methyldiethanolamine solution

International Nuclear Information System (INIS)

Shokouhi, Mohammad; Ahmadi, Reza

2016-01-01

Highlights: • Measurement solubility of H 2 S in 46.78 mass% MDEA aqueous solutions. • Measurement density of H 2 S loaded of MDEA aqueous solution. • Measurement viscosity of H 2 S loaded of MDEA aqueous solution. • Correlation of the density and viscosity of H 2 S loaded of MDEA aqueous solution using modified setchenow equation. - Abstract: The density and viscosity of H 2 S-loaded aqueous 46.78 mass% methyldiethanolamine solution were experimentally measured accompanied with the solubility of H 2 S at temperatures (313.15, 328.15 and 343.15) K, pressures from vapor pressure of fresh solution up to 1.0 MPa and loadings up to 1.00 mol of H 2 S per 1 mol of amine. All experimental trials have been carried out using the new setup developed in our laboratory. It was observed that both density and viscosity of mixtures decrease by increasing temperature and density increase by increasing acid gas solubility (loading) by about 4.7%, whereas viscosity has a complicated behavior with H 2 S solubility. Viscosity decreases by increasing acid gas solubility (loading) at 313.15 K by about 20.6% and at 328.15 K by about 15.0%, but it is comparable at 343.15 K in terms of H 2 S solubility. Finally, the experimental density and viscosity data correlated using Modified Setchenow equation.

Effect of gamma irradiation on viscosity of aqueous solutions of some natural polymers

International Nuclear Information System (INIS)

Nguyen Tan Man; Truong Thi Hanh; Le Quang Luan; Le Hai; Nguyen Quoc Hien

2000-01-01

Effect of gamma irradiation on viscosity of aqueous solution of alginate and carbon xylmethyl cellulose (CMC) irradiated in solid state has been carried out. the viscosity of aqueous solution of alginate and CMC decreased remarkably with increasing dose and the viscosity of 2% solution of above polymers irradiated at 50 kGy was about 100 times lower than the original one. (author)

XPS study of the passive layers formed on lead in aqueous nitrate solutions

International Nuclear Information System (INIS)

Uchida, Miho; Okuwaki, Akitsugu

1997-01-01

The analysis of the lead surface immersed in aqueous nitrate solutions by X-ray photoelectron spectroscopy (XPS) shows the formation of passive oxide layer containing nitrogen compound. The oxide layer formed on the lead surface in aqueous ammonium nitrate solution was hydrolyzed and cracked. (author)

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

Science.gov (United States)

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.

Effect of pH on the corrosion behaviour of SUS321 in the ammonia aqueous solution

International Nuclear Information System (INIS)

Park, Sang Yoon; Jeong, Y. H.; Baek, J. H.; Choi, B. K.; Lee, M. H.; Choi, B. S.; Yoon, J. H.; Lee, D. J.

2003-02-01

The corrosion characteristics of SUS321 for pressure vessel of SMART in pure water, ammonia aqueous solutions of pH 8.5 ∼ 11.5 at 300 .deg. C were evaluated by using static autoclaves. SUS321 specimen in the high temperature ammonia aqueous solution has weight gain or loss by the 4 reactions. And it depends on the refreshing period of the aqueous solution. So additional experiments by recirculating loop system were required to evaluate the corrosion behaviour of SUS321 in the ammonia aqueous solution

Physicochemical characterization of in situ drug-polymer nanocomplex formed between zwitterionic drug and ionomeric material in aqueous solution

Energy Technology Data Exchange (ETDEWEB)

Salamanca, Constain H., E-mail: chsalamanca@icesi.edu.co [Pharmaceutical physical chemistry laboratory, Department of Pharmacy, Faculty of Natural Sciences, ICESI University, Cali (Colombia); Castillo, Duvan F.; Villada, Juan D. [Pharmaceutical physical chemistry laboratory, Department of Pharmacy, Faculty of Natural Sciences, ICESI University, Cali (Colombia); Rivera, Gustavo R. [SIT Biotech GmbH, BMZ 2 Otto-Hahn-Str. 15, 44227 Dortmund (Germany)

2017-03-01

Biocompatible polymeric materials with the potential to form functional structures, in association with different therapeutic molecules, in physiological media, represent a great potential for biological and pharmaceutical applications. Therefore, here the formation of a nano-complex between a synthetic cationic polymer and model drug (ampicillin trihydrate) was studied. The formed complex was characterized by size and zeta potential measurements, using dynamic light scattering and capillary electrophoresis. Moreover, the chemical and thermodynamically stability of these complexes were studied. The ionomeric material, here referred as EuCl, was obtained by equimolar reaction between Eudragit E and HCl. The structural characterization was carried out by potentiometric titration, FTIR spectroscopy, and DSC. The effect of pH, time, polymer concentration and ampicillin/polymer molar ratio over the hydrodynamic diameter and zeta potential were established. The results show that EuCl ionomer in aqueous media presents two different populations of nanoparticles; one of this tends to form flocculated aggregates in high pH and concentrations, by acquiring different conformations in solution by changing from a compact to an extended conformation. Moreover, the formation of an in situ interfacial polymer-drug complex was demonstrated, this could slightly reduce the hydrolytic degradation of the drug while affecting its solubility, mainly under acidic conditions. - Highlights: • The EuCl ionomer in aqueous media presents two different populations of nanoparticle, corresponding to proximally 15 nm and 150 nm. • The EuCl ionomer in aqueous media may form different structure depending on the pH and polymer concentration, which tends to form flocculated aggregates in high pH and concentrations. • The formation of an in situ interfacial polymer-drug complex was demonstrated, which could slightly reduce the hydrolytic degradation of the drug and affecting its solubility in

Pitting corrosion of zirconium in aqueous solution

International Nuclear Information System (INIS)

El Shayeb, H.A.; Abd El Wahab, F.M.; Abd Elk Meguid, E.A.

1994-01-01

The open circuit potentials of the Zr electrode are followed as a function of time in various aqueous solutions till attainment of steady state values.The results are discussed on the basis of oxide film thickening and repair. Pitting corrosion of Zr was examined in chloride solutions using the potentiodynamic technique. The effect of some inorganic and organic additives was also investigated for inhibiting the pitting corrosion of Zr and the relative performance is presented and discussed. (author). 21 refs., 6 figs., 1 tab

Stabilizers of edaravone aqueous solution and their action mechanisms. 2. Glutathione

OpenAIRE

Tanaka, Masahiko; Motomiya, Satsuki; Fujisawa, Akio; Yamamoto, Yorihiro

2017-01-01

Edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one) has garnered attention since its approval for amyotrophic lateral sclerosis in Japan (2015) and the United States (2017). Edaravone is administered intravenously, and as such, is distributed in the form of an aqueous solution. However, aqueous solutions of edaravone are very unstable because they present as edaravone anions, which become edaravone radicals when the anion donates an electron to free radicals including oxygen. In this study, gluta...

Kinetics of the decomposition and the estimation of the stability of 10% aqueous and non-aqueous hydrogen peroxide solutions

Directory of Open Access Journals (Sweden)

Zun Maria

2014-12-01

Full Text Available In this study, the stability of 10% hydrogen peroxide aqueous and non-aqueous solutions with the addition of 6% (w/w of urea was evaluated. The solutions were stored at 20°C, 30°C and 40°C, and the decomposition of hydrogen peroxide proceeded according to first-order kinetics. With the addition of the urea in the solutions, the decomposition rate constant increased and the activation energy decreased. The temperature of storage also affected the decomposition of substance, however, 10% hydrogen peroxide solutions prepared in PEG-300, and stabilized with the addition of 6% (w/w of urea had the best constancy.

Fluoresence quenching of riboflavin in aqueous solution by methionin and cystein

International Nuclear Information System (INIS)

Droessler, P.; Holzer, W.; Penzkofer, A.; Hegemann, P.

2003-01-01

The fluorescence quantum distributions, fluorescence quantum yields, and fluorescence lifetimes of riboflavin in methanol, DMSO, water, and aqueous solutions of the sulphur atom containing amino acids methionin and cystein have been determined. In methanol, DMSO, and water (pH=4-8) only dynamic fluorescence reduction due to intersystem crossing and internal conversion is observed. In aqueous methionin solutions of pH=5.25-9 a pH independent static and dynamic fluorescence quenching occurs probably due to riboflavin anion-methionin cation pair formation. In aqueous cystein solutions (pH range from 4.15 to 9) the fluorescence quenching increases with rising pH due to cystein thiolate formation. The cystein thiol form present at low pH does not react with neutral riboflavin. Cystein thiolate present at high pH seems to react with neutral riboflavin causing riboflavin deprotonation (anion formation) by cystein thiolate reduction to the cystein thiol form

Removal of Nickel from Aqueous Solution by Hard-Shell Pistachios

Directory of Open Access Journals (Sweden)

Shayan Shamohammadi

2013-08-01

Full Text Available Nickel is one of the heavy metals which commonly can be found in industrial wastewater. Many studies have been done on agricultural waste for the removal of nickel from aqueous solutions. The purpose of this study is to identify hard-shell pistachios as a local attraction for removal of nickel from aqueous solution. Nickel adsorption isotherm models are studied using shell pistachios. Pistachio shell was chosen which its particle size is between 800-600 microns. The stock solution of nickel ions was prepared mixing nickel nitrate with distilled water. The results showed that the maximum absorption efficiency occurs (73.3% at pH=8. Also, it was shown that with increasing adsorbent dose, equilibrium time decreased within constant concentration. Examination of uptake isotherm models showed that models of Freundlich, BET, Radke-Praunitz, Redlich-Peterson and Sips describe data in 97% level of confidence well,  however Freundlich and Sips isotherm models has the lowest error factor 0.10597 and 0/10598 respectively and the highest correlation coefficient (0.9785. Comparison of adsorbent capacity within removal of nickel from aqueous solution shows that Pistachio shell with special absorbent surface of 1.7 m2/g and uptake capacity of 0.3984 mg/g is proper than adsorbents of Kaolinite, Bagasse, sludge-ash.

Molecular mechanism of the viscosity of aqueous glucose solutions

Science.gov (United States)

Bulavin, L. A.; Zabashta, Yu. F.; Khlopov, A. M.; Khorol'skii, A. V.

2017-01-01

Experimental relations are obtained for the viscosity of aqueous glucose solutions in the temperature range of 10-80°C and concentration range 0.01-2.5%. It is found that the concentration dependence of fluidity is linear when the concentration is higher than a certain value and varies at different temperatures. The existence of such a dependence indicates that the mobilities of solvent and solute molecules are independent of the concentration of solutions. This assumption is used to construct a theoretical model, in which the structure of an aqueous glucose solution is presented as a combination of two weakly interacting networks formed by hydrogen bonds between water molecules and between glucose molecules. Theoretical relations are obtained using this model of network solution structure for the concentration and temperature dependence of solution viscosity. Experimental data are used to calculate the activation energies for water ( U w = 3.0 × 10-20 J) and glucose molecules ( U g = 2.8 × 10-20 J). It is shown that the viscosity of a solution in such a network structure is governed by the Brownian motion of solitons along the chains of hydrogen bonds. The weak interaction between networks results in the contributions to solution fluidity made by the motion of solitons in both of them being almost independent.

Ion from Aqueous Solution using Magnetite, Activated Carbon

African Journals Online (AJOL)

ADOWIE PERE

Thermodynamic studies on Adsorption of lead (II) Ion from Aqueous Solution using. Magnetite ... process industries and agricultural activities, which tends to ... osmosis. These processes are however, not economically feasible for small scale industries .... Freundlich coefficient. ..... from binary component system, Beni-suef.

Analysis and modeling of alkali halide aqueous solutions

DEFF Research Database (Denmark)

Kim, Sun Hyung; Anantpinijwatna, Amata; Kang, Jeong Won

2016-01-01

on calculations for various electrolyte properties of alkali halide aqueous solutions such as mean ionic activity coefficients, osmotic coefficients, and salt solubilities. The model covers highly nonideal electrolyte systems such as lithium chloride, lithium bromide and lithium iodide, that is, systems...

Photoionization of rhodamine dyes adsorbed at the aqueous solution surfaces investigated by synchrotron radiation

International Nuclear Information System (INIS)

Seno, Koichiro; Ishioka, Toshio; Harata, Akira; Hatano, Yoshihiko

2002-01-01

Photoionization spectroscopy using synchrotron radiation as a photon source was applied to the aqueous solution surfaces of rhodamine B (RhB), rhodamine 6G (Rh6G), and rhodamine 101 (Rh101) with their concentration of 0-100 μmol dm -3 . Synchrotron radiation was irradiated upon the solution surface between two electrodes in the photon energy range of 4-7 eV, and photoionization current was measured by a pico-ammeter. The photocurrent for each of the rhodamine aqueous solution surface showed an increase with the photon energy above a threshold photon energy. The photoionization threshold of RhB at the aqueous solution surface was 5.6 eV, which was smaller than that in the gas phase. The intensity of photoionization current of Rh6G was smaller than that of RhB or Rh101. Photoionization processes and the state of Rhodamine dye molecules at the aqueous solution surface were discussed in connection with results of surface tension measurements. (author)

Physical Removal of Anions from Aqueous Media by Means of a Macrocycle-Containing Polymeric Network

KAUST Repository

Ji, Xiaofan

2018-02-13

Reported here is a hydrogel-forming polymer network that contains a water-soluble tetracationic macrocycle. Upon immersion of this polymer network in aqueous solutions containing various inorganic and organic salts, changes in the physical properties are observed that are consistent with absorption of the constituent anions into the polymer network. This absorption is ascribed to host-guest interactions involving the tetracationic macrocyclic receptor. Removal of the anions may then be achieved by lifting the resulting hydrogels out of the aqueous phase. Treating the anion-containing hydrogels with dilute HCl leads to the protonation-induced release of the bound anions. This allows the hydrogels to be recycled for reuse. The present polymer network thus provides a potentially attractive approach to removing undesired anions from aqueous environments.

Sound velocity in potassium hydroxide aqueous solution

International Nuclear Information System (INIS)

Tsapuryan, Kh.D.; Aleksandrov, A.A.; Kochetkov, A.I.

1992-01-01

Measurements of ultrasonic velocities in potassium hydroxide aqueous solutions are carried out within the frames of studies on improvement of water chemistry in NPP cooling systems. Method of echo pulses superposition with acoustic path length of 41.447 mm is used for measurements. The measurements are performed at 2.6 MHz frequency. Complex temperature dependence of ultrasonic velocity is determined. Ultrasonic velocity dependence on pressure is close to linear one. The formula for calculation of thermodynamic properties of the studied solutions on the basis of experimental data obtained is proposed

Removal of radium from aqueous sulphate solutions

International Nuclear Information System (INIS)

Weir, D.R.; Masters, J.T.; Neven, M.

1983-01-01

Radium is often present in ores and an aqueous solution associated with the ore may consequently contain dissolved radium. It is frequently necessary to remove radium from such solutions to reduce the total radium content to a prescribed low level before the solution can be returned to the environment. The present invention is based on the discovery that the total radium content can be reduced to a satisfactory level within a reasonable time by adding a soluble barium salt to a radium-containing sulphate solution which also contains dissolved magnesium at a pH not greater than about 0 to precipitate radium as barium radium sulphate, raising the pH to at least 11 to precipitate an insoluble magnesium compound which collects the barium radium sulphate precipitate, and separating substantially all of the precipitates from the solution

Hydrate phase equilibria of CO2+N2+aqueous solution of THF, TBAB or TBAF system

DEFF Research Database (Denmark)

Sfaxi, Imen Ben Attouche; Durand, Isabelle; Lugo, Rafael

2014-01-01

We report hydrate dissociation conditions of CO2 (15 and 30mol%)+N2 (85 and 70mol%) in the presence of aqueous solutions of THF, TBAB or TBAF. The concentrations of TBAB and TBAF in the aqueous solutions are 5wt% and 9wt% while THF concentration in aqueous solution is 3mol%. Two different experim...

Recrystallization of freezable bound water in aqueous solutions of medium concentrations

Institute of Scientific and Technical Information of China (English)

赵立山; 潘礼庆; 纪爱玲; 曹则贤; 王强

2016-01-01

For aqueous solutions with freezable bound water, vitrification and recrystallization are mingled, which brings diffi-culty 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 concentra-tion 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 recrys-tallization. Our results may be helpful for understanding the dynamics of supercooled aqueous solutions and for improving their manipulation in various industries.

Orientational order and dynamics of water in bulk and in aqueous solutions of uranyl ions

International Nuclear Information System (INIS)

Chopra, Manish; Choudhury, Niharendu

2014-01-01

Molecular dynamics simulations in canonical ensemble of aqueous solutions of uranyl nitrate and bulk water at ambient condition have been carried out to investigate orientational order and dynamics of water. The orientational distributions of water around a central water molecule in bulk water and around a uranyl ion in an aqueous uranyl solution have been calculated. Orientational dynamics of water in bulk and in aqueous uranyl nitrate solution have also been analysed. (author)

Removal of Murexide from Aqueous Solution Using Pomegranate bark as adsorbent

International Nuclear Information System (INIS)

Ishaq, M.I.; Shakirullah, M.; Ahmad, I.; Sultan, S.; Saeed, K.

2012-01-01

The adsorption of Murexide from aqueous solution onto the Pomegranate bark was investigated at room temperature. The morphological study presented that the HNO/sub 3/ treatment increased the surface roughness of the adsorbent. EDX studies show that the untreated Pomegranate bark had carbon content (52 wt %) and oxygen content (44 wt %) while in the case of HNO/sub 3/ treated pomegranate bark, the carbon quantity decreased (42 wt %) and oxygen quantity (52 wt %) increased. The results showed that the adsorption of Murexide dye from aqueous solution was increased as increased the adsorption time and then equilibrium was reached after 30 min of adsorption time. The HNO/sub 3/ treated Pomegranate bark adsorbed high quantity of Murexide (1.7 mg/g) as compared to untreated Pomegranate bark (0.73 mg/g), which might be due to increased surface roughness. The adsorption of Murexide was also studied at different pH, which presented that low pH was favorable for the removal of color material from aqueous solution. (author)

Photolysis of imidacloprid in aqueous solution

International Nuclear Information System (INIS)

Moza, P.N.; Hustert, K.; Feicht, E.; Kettrup, A.

1998-01-01

The photolysis of the insecticide imidacloprid in aqueous solution has been examined. Irradiation at 290 nm resulted in 90 % substrate transformation in 4 h. The degradation approximately followed first order kinetics; the rate constant is 1.6 × 10 −4 s −1 and half-life 1.2 h. 6-Chloronicotinaldehyde, N-methylnicotinacidamide, 1-(6-chloronicotinyl)imidazolidone and 6-chloro-3-pyridyl-methylethylendiamine were the main photoproducts identified by CG-MS analysis. (author)

Radiation-induced nitration of organic compounds in aqueous solutions

International Nuclear Information System (INIS)

Ershov, B.G.; Gordeev, A.V.; Bykov, G.L.

2009-01-01

Radiation-induced nitration of organic compounds in aqueous solutions was studied. It was found that γ-irradiation of solutions containing acetic and nitric acid and/or their salts gives nitromethane. Dependences of the product yield on the absorbed dose and the contents of components were established. The mechanism of radiation nitration involving radicals is discussed. (author)

On mechanism of chlorophos radiation-chemical decomposition in aqueous solutions

International Nuclear Information System (INIS)

Danilin, D.I.; Shubin, V.N.

1992-01-01

Quantitative indices of chlorophos decomposition in a aqueous solution and in solutions with a number of additions are studied. Chlorine ions and substances containing the carbonyl group are found among the products of gamma-irradiation of low-concentration chlorophos solutions. The data supporting the running of radiation destructive reactions of reduction nature rather than oxidation type, are presented

Sorption behaviour of W, Hf, Lu, U, and Th on ion exchangers from HCl/H2O2 solutions. Model experiments for chemical studies of seaborgium (Sg)

International Nuclear Information System (INIS)

Schumann, D.; Andrassy, M.; Nitsche, H.; Misiak, R.; Schaedel, M.; Bruechle, W.; Schausten, B.; Kratz, J.V.

1997-08-01

In model experiments with W, Hf, Th, and U radionuclides, a chemical system was developed for the separation of seaborgium from element 104 and heavy actinides, i.e., cation exchange on DOWEX 50 x 8 from solutions containing 0.1-1.0 M HCl and 0.5-2.0 vol.% H 2 O 2 . The system should be suitable for fast on-line experiments if seaborgium exibits a non-uranium-like behaviour. Adding hydrogen peroxide to mixed HCl/HF solutions suppresses the partial sorption of W and, presumably seaborgium, on the cation exchanger. This way, the elution volume can be minimized. Prospects for anion exchange separations of group 6 from 4 elements are also briefly discussed. (orig.)

The synthesis of nucleotide in the aqueous solution induced by low energy ions

International Nuclear Information System (INIS)

Shi Huaibin; Shao Chunlin; Wang Xiangqin; Yu Zengliang

2000-08-01

A new apparatus was designed to induce reactions in aqueous solution by introducing low energy ions into the aqueous solution, this apparatus overcome the defaults of the old ones which demanded vacuum and made it possible to study the action among solutions, it also expanded the ion implantation biology. The role of low energy ions was introduced into the study of the origin of life, primitive earth conditions were imitated to study prior-life synthesis of nucleotide by introducing low energy ions into aqueous solution, low energy N + was implanted into adenine supersaturation solution including D-ribose and NH 4 H 2 PO 4 , it was confirmed that 5'-AMP was gained by HPLC analysis of the products. In comparison with other methods in this field, this one is simpler and nearer to the primitive earth conditions, thus it provided a new try for the studying of the origin of life

KINETICS OF THE HYDROXYPROPYLATION OF POTATO STARCH IN AQUEOUS-SOLUTION

NARCIS (Netherlands)

LAMMERS, G; STAMHUIS, EJ; BEENACKERS, AACM

Kinetic results are presented for the hydroxypropylation of Potato starch with methyloxirane in aqueous solution. Reaction temperatures were varied from 303 to 362 K. Sodium hydroxide was used as a catalyst. The overall conversion rate of methyloxirane in alkaline starch solution is determined by

The use of new modified poly(acrylamide chelating resin with pendent benzothiazole groups containing donor atoms in the removal of heavy metal ions from aqueous solutions

Directory of Open Access Journals (Sweden)

Semmedu Selvaraj Kalaivani

2014-03-01

Full Text Available The adsorption studies of poly(6-(ethoxybenzothiazole acrylamide (PEBTA, for Cu(II and Zn(II metal ions removal from an aqueous solution have been investigated, as a function of solution pH, adsorbent dose, contact time, initial metal ion concentration and temperature. The chemical and structural characteristics of the adsorbent were determined by the FT-IR, 1H-NMR, TGA, SEM, and EDAX analysis. The maximum adsorption capacities of the adsorbent for Cu(II and Zn(II ions, as calculated from the Langmuir isotherm model, were 273.5 and 216.4 mg/g, respectively. The adsorption kinetic studies show that the adsorption of Cu(II and Zn(II ions onto PEBTA follows the pseudo second order kinetic model. Thermodynamic parameters such as ΔG°, ΔH° and ΔS° were also evaluated, and it has been found that the adsorption process is feasible, spontaneous and exothermic in nature. Desorption studies were carried out using 0.3 N HCl, and it revealed that the adsorbed Cu(II and Zn(II ions can be easily removed. The adsorption–desorption process is reversible, and this indicates that PEBTA is an effective adsorbent for the removal of heavy metal ions from an aqueous medium.

Removal of radium from aqueous solutions using adsorbent produced from coconut coir pith

International Nuclear Information System (INIS)

Zalina Laili; Muhamat Omar; Mohd Zaidi Ibrahim; Esther Phillip; Mohd Abdul Wahab Yusof; Hassan, A.

2008-08-01

A study was conducted to evaluate the potential use of the coconut coir pith as an adsorbent for the removal of radium from aqueous solutions. Experiments to establish adsorptions as a function of pH and contact time were carried out. The results showed that radium adsorption are dependent upon pH and contact time of coconut coir pith with aqueous solutions. 70-80% of radium were adsorbed in the neutral to alkaline pH range. The amount of radium adsorbed also increased with contact time, reaching an optimum after 250 min. Thus, it can be concluded that the coconut coir pith has the potential to be used as an adsorbent in radium removal from aqueous solutions. (Author)

Densities concentrations of aqueous of uranyl nitrate solutions

International Nuclear Information System (INIS)

Rodrigo Otero, A.; Rodriguez Hernandez, B.; Fernandez Rodriguez, L.

1966-01-01

The ratio density-concentration of aqueous uranyl nitrate solutions expressed as U 3 O 8 grams/liter, U grams/liter and hexahydrate uranyl nitrate weight percent at different temperatures, are established. Experimental values are graphically correlated and compared whit some published data. (Author) 2 refs

Volumetric and viscometric studies of some drugs in aqueous solutions at different temperatures

International Nuclear Information System (INIS)

Dhondge, Sudhakar S.; Zodape, Sangesh P.; Parwate, Dilip V.

2012-01-01

Highlights: ► Study of aqueous solutions of biologically important compounds has been reported. ► MH is used for treating type II diabetes, RH is in treatment of peptic ulcer and TH is used to treat severe pain. ► All the compounds act as structure makers by volumetric studies. ► MH and RH act as weak structure breakers and TH acts as a weak structure maker by viscometric studies. - Abstract: Density and viscosity measurements are reported for aqueous solutions of the drugs like Metformin hydrochloride (MH), Ranitidine hydrochloride (RH) and Tramadol hydrochloride (TH) at different temperatures T = (288.15, 298.15, and 308.15) K within the concentration range (0 to 0.15) mol · kg −1 . The density and viscosity data are used to obtain apparent molar volume of solute (φ V ) and relative viscosity (η r ) of aqueous solutions at different temperatures. The limiting apparent molar volume of solute (φ V 0 ), limiting apparent molar expansivity (φ E 0 ), thermal expansion coefficient (α ∗ ), hydration number (n h ), Jones–Dole equation viscosity A and B coefficients, experimental slope (S V ) at different temperatures, and temperature coefficient of Bi.e.(dB/dT) at T = 298.15 K were also obtained. The results obtained have been interpreted in terms of solute–solvent and solute–solute interactions and structure making/breaking ability of solute in the aqueous solution.

Application of AzollaFiliculoides Biomass in Acid Black 1 Dye Adsorption from Aqueous Solution

Directory of Open Access Journals (Sweden)

Mohammad Ali Zazouli

2014-09-01

Full Text Available Background and purpose: The textile dyes are considered as important pollutants due to the toxicity on human and environment. Therefore, the dye removal from industrial effluents is necessary. This study evaluates the ability of Azolla for the adsorption of acid black 1 (AB1 dye from aqueous solution. Materials and Methods: This was an experimental-laboratory study. The Azolla biomass was sun dried, crushed and sieved to particle sizes in the range of 1-2 mm. Then, it treated with 0.1 M HCl for 5 h, followed by washing with distilled water, and it used as an adsorbent. The effect of study parameter was investigated, and the residues AB1 concentration was measured by DR2800 spectrophotometer at in λmax = 622 nm. Results: The results indicated that the efficiency of AB1 adsorption decreased with increased initial dye concentration. It increased with increased contact time and adsorbent. The highest adsorption efficiency was occurred at pH = 2. The equilibrium data were the best fitted on Langmuir isotherm and pseudo-second-order kinetic model. Conclusion: The Azolla could present high ability in dye removal. Therefore, it can be used as inexpensive and effective adsorbent in textile effluent treatment.

Adsorption behaviors of trivalent actinides and lanthanides on pyridine resin in lithium chloride aqueous solution

International Nuclear Information System (INIS)

Tatsuya Suzuki

2013-01-01

The adsorption behaviors of trivalent actinides and lanthanides on pyridine resin in lithium chloride aqueous solution were investigated. The adsorbed amounts of lanthanides and the degree of mutual separation of lanthanides increased with an increase in the concentration of lithium chloride in aqueous solution. The group separation of the trivalent actinides and lanthanides was observed. This separation phenomenon is similar in a hydrochloric acid solution. However, the adsorption behavior of lanthanides in lithium chloride is different from their behavior in a hydrochloric acid solution. This fact shows that the adsorption mechanisms of lanthanides in a lithium chloride aqueous solution and in a hydrochloric acid solution are different; the adsorption mechanisms are attributed to the ion exchange in a hydrochloric acid solution, and to the complex formation with pyridine group in a lithium chloride solution. (author)

Dermal absorption of a dilute aqueous solution of malathion

Directory of Open Access Journals (Sweden)

Scharf John

2008-01-01

Full Text Available Malathion is an organophosphate pesticide commonly used on field crops, fruit trees, livestock, agriculture, and for mosquito and medfly control. Aerial applications can result in solubilized malathion in swimming pools and other recreational waters that may come into contact with human skin. To evaluate the human skin absorption of malathion for the assessment of risk associated with human exposures to aqueous solutions, human volunteers were selected and exposed to aqueous solutions of malathion. Participants submerged their arms and hands in twenty liters of dilute malathion solution in either a stagnant or stirred state. The "disappearance method" was applied by measuring malathion concentrations in the water before and after human exposure for various periods of time. No measurable skin absorption was detected in 42% of the participants; the remaining 58% of participants measured minimal absorbed doses of malathion. Analyzing these results through the Hazard Index model for recreational swimmer and bather exposure levels typically measured in contaminated swimming pools and surface waters after bait application indicated that these exposures are an order of magnitude less than a minimal dose known to result in a measurable change in acetylcholinesterase activity. It is concluded that exposure to aqueous malathion in recreational waters following aerial bait applications is not appreciably absorbed, does not result in an effective dose, and therefore is not a public health hazard.

Electrogenerated chemiluminescence induced by sequential hot electron and hole injection into aqueous electrolyte solution

Energy Technology Data Exchange (ETDEWEB)

Salminen, Kalle; Kuosmanen, Päivi; Pusa, Matti [Aalto University, Department of Chemistry, Laboratory of Analytical Chemistry, P.O. Box 16100, FI-00076 Aalto (Finland); Kulmala, Oskari [University of Helsinki, Department of Physics, P.O. Box 64, FI-00014 (Finland); Håkansson, Markus [Aalto University, Department of Chemistry, Laboratory of Analytical Chemistry, P.O. Box 16100, FI-00076 Aalto (Finland); Kulmala, Sakari, E-mail: sakari.kulmala@aalto.fi [Aalto University, Department of Chemistry, Laboratory of Analytical Chemistry, P.O. Box 16100, FI-00076 Aalto (Finland)

2016-03-17

Hole injection into aqueous electrolyte solution is proposed to occur when oxide-coated aluminum electrode is anodically pulse-polarized by a voltage pulse train containing sufficiently high-voltage anodic pulses. The effects of anodic pulses are studied by using an aromatic Tb(III) chelate as a probe known to produce intensive hot electron-induced electrochemiluminescence (HECL) with plain cathodic pulses and preoxidized electrodes. The presently studied system allows injection of hot electrons and holes successively into aqueous electrolyte solutions and can be utilized in detecting electrochemiluminescent labels in fully aqueous solutions, and actually, the system is suggested to be quite close to a pulse radiolysis system providing hydrated electrons and hydroxyl radicals as the primary radicals in aqueous solution without the problems and hazards of ionizing radiation. The analytical power of the present excitation waveforms are that they allow detection of electrochemiluminescent labels at very low detection limits in bioaffinity assays such as in immunoassays or DNA probe assays. The two important properties of the present waveforms are: (i) they provide in situ oxidation of the electrode surface resulting in the desired oxide film thickness and (ii) they can provide one-electron oxidants for the system by hole injection either via F- and F{sup +}-center band of the oxide or by direct hole injection to valence band of water at highly anodic pulse amplitudes. - Highlights: • Hot electrons injected into aqueous electrolyte solution. • Generation of hydrated electrons. • Hole injection into aqueous electrolyte solution. • Generation of hydroxyl radicals.

Removal of Phenol in Aqueous Solution Using Kaolin Mineral Clay

International Nuclear Information System (INIS)

Sayed, M.S.

2008-01-01

Kaolin clay were tested for phenol removal as toxic liquid waste from aqueous waste water. Several experimental conditions such as weight and particle size of clay were investigated to study batch kinetic techniques, also the ph and concentration of the phenol solution were carried out. The stability of the Langmuir adsorption model of the equilibrium data were studied for phenol sorbent clay system. Infrared spectra, thermogravimetric and differential thermal analysis techniques were used to characterize the behavior of kaolin clay and kaolin clay saturated with phenol. The results obtained showed that kaolin clay could be used successfully as an efficient sorbent material to remove phenol from aqueous solution

Solidification of radioactive aqueous solution

Energy Technology Data Exchange (ETDEWEB)

Aikawa, Hideaki; Kato, Kiyoshi; Wadachi, Yoshiki

1970-09-07

A process for solidifying a radioactive waste solution is provided, using as a solidifying agent a mixture of calcined gypsum and burnt vermiculite. The quantity ratio of the mixture is preferred to be 1:1 by volume. The quantity of impregnation is 1/2 of the volume of the total quantity of the solidifying agent. In embodiments, 10 liters of plutonium waste solution was mixed with a mixture of 1:1 calcined gypsum and burnt vermiculite contained in a 20-liter cylindrical steel container lined with asphalt. The plutonium waste solution from the laboratory was neutralized with a caustic soda aqueous solution to prevent explosion due to the nitration of organic compounds. The neutralization is not always necessary. A market available dental gypsum was calcined at 400 to 500/sup 0/C and a vermiculite from Illinois was burnt at 1,100/sup 0/C to prepare the agents. The time required for the impregnation with 10 liters of plutonium solution was four minutes. After impregnation, the temperature rose to 40/sup 0/C within 30 minutes to one hour. Next, it was cooled to room temperature by standing for 3-4 hours. Solidification time was about 1 hour. The Japan Atomic Energy Research Insitute had treated and disposed about 1,000 tons of plutonium waste by this process as of August 19, 1970.

Preparation of fluorescent polyaniline nanoparticles in aqueous solutions

Energy Technology Data Exchange (ETDEWEB)

Alves, Kleber G. B. [Universidade Federal de Pernambuco, Departamento de Engenharia Mecanica (Brazil); Melo, Etelino F. de [Universidade Federal de Pernambuco, Departamento de Quimica Fundamental (Brazil); Andrade, Cesar A. S. [Universidade Federal de Pernambuco, Departamento de Bioquimica (Brazil); Melo, Celso P. de, E-mail: celso@df.ufpe.br [Universidade Federal de Pernambuco, Departamento de Fisica (Brazil)

2013-01-15

We report the synthesis of stable polyaniline nanoparticles (PANI{sub N}Ps) based on the chemical oxidative polymerization of aniline in aqueous solutions of surfactants. Surfactants of three different types-cationic (dodecyltrimethylammonium bromide-DTAB), anionic (sodium dodecyl sulfate-SDS), and non-ionic (Triton X-405-TX-405)-were used. The resulting PANI{sub N}Ps{sub s}urfactant samples were characterized through UV-Vis, fluorescence and Fourier transform infrared spectroscopies, and scanning electronic microscopy (SEM). We have verified that the color of the PANI{sub N}Ps{sub s}urfactant dispersions is affected by a change in the pH of the solution. The PANI-NPs{sub s}urfactant colloidal suspensions in aqueous solution present a surprising high fluorescence quantum yield value (ranging from 1.9 Multiplication-Sign 10{sup -3} to 6.9 Multiplication-Sign 10{sup -3}) that can be controlled as a function of the pH, a fact that we associate to the corresponding protonation degree of the PANI polymeric chains. We suggest that these fluorescent nanocomposites can find important technological applications in different areas such as organic light emitting devices, biosensors, and pigments for coatings.

Preparation of fluorescent polyaniline nanoparticles in aqueous solutions

International Nuclear Information System (INIS)

Alves, Kleber G. B.; Melo, Etelino F. de; Andrade, César A. S.; Melo, Celso P. de

2013-01-01

We report the synthesis of stable polyaniline nanoparticles (PANI N Ps) based on the chemical oxidative polymerization of aniline in aqueous solutions of surfactants. Surfactants of three different types—cationic (dodecyltrimethylammonium bromide—DTAB), anionic (sodium dodecyl sulfate—SDS), and non-ionic (Triton X-405–TX-405)—were used. The resulting PANI N Ps s urfactant samples were characterized through UV–Vis, fluorescence and Fourier transform infrared spectroscopies, and scanning electronic microscopy (SEM). We have verified that the color of the PANI N Ps s urfactant dispersions is affected by a change in the pH of the solution. The PANI-NPs s urfactant colloidal suspensions in aqueous solution present a surprising high fluorescence quantum yield value (ranging from 1.9 × 10 −3 to 6.9 × 10 −3 ) that can be controlled as a function of the pH, a fact that we associate to the corresponding protonation degree of the PANI polymeric chains. We suggest that these fluorescent nanocomposites can find important technological applications in different areas such as organic light emitting devices, biosensors, and pigments for coatings.

In vivo release of bupivacaine from subcutaneously administered oily solution. Comparison with in vitro release

DEFF Research Database (Denmark)

Larsen, Dorrit Bjerg; Joergensen, Stig; Olsen, Niels Vidiendal

2002-01-01

A non-randomized cross-over study was performed with bupivacaine HCl (5 mg x ml(-1)) aqueous solution and bupivacaine free base (4.44 mg x ml(-1)) in Viscoleo/castor oil 2:1 (v/v) administered s.c. to male Wistar rats. Plasma levels were analyzed by LC-MS. Plasma profiles obtained after...... administration of oily solution showed a prolonged bupivacaine release with lower peak plasma levels as compared to administration of an aqueous formulation applied in the same compartment. t(1/2), t(max), C(max) and AUC(0-infinity) for the aqueous solution were 63+/-8 min, 19+/-16 min, 194+/-46 ng x ml(-1......) and 25,000+/-3000 ng min x ml(-1), respectively, while the corresponding data for the oil solution were 368+/-89 min, 334+/-186 min, 36+/-25 ng x ml(-1) and 25,000+/-6000 ng x min x ml(-1). The present data indicate the potential of designing an oil formulation of bupivacaine with a prolonged local...

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

Science.gov (United States)

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.

Cyclohexanone microfluidic extraction of radioactive perrhenate from acid solutions

Energy Technology Data Exchange (ETDEWEB)

Dalmázio, Ilza [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Oehlke, Elisabeth, E-mail: E.Oehlke@tudelft.nl [Section Radiation and Isotopes for Health, Department of Radiation Science and Technology, Delft University of Technology (Netherlands)

2017-07-01

Several studies have investigated the application of microfluidic devices in extraction processes. A potential use of microfluidic devices is in radionuclide generators based on solvent extraction, as the {sup 188}W/{sup 188}Re generator. The aim of this work is to present the initial results of microfluidic solvent extraction of radioactive perrhenate. Aqueous solutions of ammonium perrhenate at 0.1 mg/mL (in water, HCl or sodium tungstate) were used as feed solution and cyclohexanone as extractant. As a first step, the fluid behaviour inside the glass microchannel was evaluated to reach laminar flow. The second step was the determination of extraction efficiency using thermal neutron activated perrhenate to produce feed solutions. The extraction conditions permitted liquid-liquid contact times as short as 0.5 s. Increasing of the contact time, resulted in a higher extraction efficiency of perrhenate, e.g. 14 % for 0.5 s and 32 % for 1.1 s using a 0.1 mol/L HCl feed solution. The extraction of perrhenate improved also when applying a feed solution with higher acidity, e.g. 52% for 1 mol/L HCl with contact time of 1.1 s. The influence of adding sodium tungstate to the feed solution was also examined. To the best of our knowledge, these are the first results related to perrhenate solvent extraction using a microfluidic device. The usefulness of microfluidic devices to screen extraction conditions was demonstrated making it possible to evaluate the effect of electrolytes on the perrhenate extraction process in a short time-frame. (author)

Cyclohexanone microfluidic extraction of radioactive perrhenate from acid solutions

International Nuclear Information System (INIS)

Dalmázio, Ilza; Oehlke, Elisabeth

2017-01-01

Several studies have investigated the application of microfluidic devices in extraction processes. A potential use of microfluidic devices is in radionuclide generators based on solvent extraction, as the 188 W/ 188 Re generator. The aim of this work is to present the initial results of microfluidic solvent extraction of radioactive perrhenate. Aqueous solutions of ammonium perrhenate at 0.1 mg/mL (in water, HCl or sodium tungstate) were used as feed solution and cyclohexanone as extractant. As a first step, the fluid behaviour inside the glass microchannel was evaluated to reach laminar flow. The second step was the determination of extraction efficiency using thermal neutron activated perrhenate to produce feed solutions. The extraction conditions permitted liquid-liquid contact times as short as 0.5 s. Increasing of the contact time, resulted in a higher extraction efficiency of perrhenate, e.g. 14 % for 0.5 s and 32 % for 1.1 s using a 0.1 mol/L HCl feed solution. The extraction of perrhenate improved also when applying a feed solution with higher acidity, e.g. 52% for 1 mol/L HCl with contact time of 1.1 s. The influence of adding sodium tungstate to the feed solution was also examined. To the best of our knowledge, these are the first results related to perrhenate solvent extraction using a microfluidic device. The usefulness of microfluidic devices to screen extraction conditions was demonstrated making it possible to evaluate the effect of electrolytes on the perrhenate extraction process in a short time-frame. (author)

Removal of Hexavalent Chromium from Aqueous Solutions using ...

African Journals Online (AJOL)

The hexavalent chromium exists in aquatic media as water soluble complex anions and persist. These are concentrated in industrial waste water especially from the tannery industries and release of effluents from industries adversely affects the environment. The removal of heavy metals from aqueous solutions is carried ...

Forced Spreading of Aqueous Solutions on Zwitterionic Sulfobetaine Surfaces for Rapid Evaporation and Solute Separation.

Science.gov (United States)

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.

Catalytic destruction of perchlorate in ferric chloride and hydrochloric acid solution with control of temperature, pressure and chemical reagents

Science.gov (United States)

Gu, Baohua; Cole, David R.; Brown, Gilbert M.

2004-10-05

A method is described to decompose perchlorate in a FeCl.sub.3 /HCl aqueous solution such as would be used to regenerate an anion exchange resin used to remove perchlorate. The solution is mixed with a reducing agent, preferably an organic alcohol and/or ferrous chloride, and can be heated to accelerate the decomposition of perchlorate. Lower temperatures may be employed if a catalyst is added.

Chemical equilibrium in the GaP-HCl and InP-HCl systems

International Nuclear Information System (INIS)

Goliusov, V.A.; Voronin, V.A.; Chuchmarev, S.K.

1983-01-01

Chemical equilibrium in the GaP-HCl and InP-HCl systems is investigated experimentally, polynomial dependence of the total pressure on temperature (800-1100 K) and hydrochloric aci concntration under the experimental conditions is obtained. The technique for equilibrium calculation in hydrogencontaining chemical systems based on the tensimetric investigation results is suggested. The equilibrium gas phase composition in the GaP(InP)-HCl systems and self consistent, within the framework of the designed equilibrium model thermodynamic characteristics are determined. The effectiveness of gas-phase indium- and gallium phosphides precipitation in the GaP(InP)-HCl systems is calculated

Aqueous solution of basic fuchsin as food irradiation dosimeter

International Nuclear Information System (INIS)

Khan, H.M.; Naz, S.

2006-01-01

Dosimetric characterization of aqueous solution of basic fuchsin has been studied spectrophotometrically for the possible application in the low-dose food irradiation dosimetry. Absorption spectra of unirradiated and irradiated solutions were determined and decrease in the absorption with the radiation dose was noted down. Radiation-induced bleaching of the dye was measured at wavelengths of maximum absorption λ max (540nm) as well as 510, 460 and 400 nm wavelengths. At all these wavelengths, the decrease in the absorbance of the dosimeter was linear with respect to the absorbed dose from 0.05 to 0.6 kGy. The stability of dosimetric solution during the post-irradiation storage in the dark at room temperature showed that after initial bleaching during first eight days, the response was almost stable for about 34 days. The effect of different light and temperature conditions also showed that the response gradually decreased during the storage period of 34 days, which shows that the basic fuchsin dye is photosensitive as well as thermally sensitive. The possibility of using aqueous solution of basic fuchsin as food irradiation dosimeter will be discussed. (authors)

Adsorption of Cu 2+ , As 3+ and Cd 2+ ions from aqueous solution ...

African Journals Online (AJOL)

The adsorption of Cu2+, Cd2+ and As3+ ions on eggshell from aqueous solution was studied under batch conditions at 30, 40, 50 and 60oC and concentrations of 10, 20, 30, 60 and 80 mg/l. The partition coefficient for the ions between aqueous solution and chicken eggshell increased with time and with increase in the ...

Experimental measurements of U24Py nanocluster behavior in aqueous solution

Energy Technology Data Exchange (ETDEWEB)

Flynn, Shannon L.; Szymanowski, Jennifer E.S.; Fein, Jeremy B. [Univ. of Notre Dame, IN (United States). Department of Civil and Environmental Engineering and Earth Sciences; Dembowski, Mateusz [Univ. of Notre Dame, IN (United States). Department of Chemistry and Biochemistry; Burns, Peter C. [Univ. of Notre Dame, IN (United States). Department of Civil and Environmental Engineering and Earth Sciences; Univ. of Notre Dame, IN (United States). Department of Chemistry and Biochemistry

2016-07-01

Uranyl peroxide nanoclusters may impact the mobility and partitioning of uranium at contaminated sites and could be used in the isolation of uranium during the reprocessing of nuclear waste. Their behavior in aqueous systems must be better understood to predict the environmental fate of uranyl peroxide nanoclusters and for their use in engineered systems. The aqueous stability of only one uranyl peroxide nanocluster, U60 (K{sub 16}Li{sub 44}[UO{sub 2}(O{sub 2})OH]{sub 60}), has been studied to date [Flynn, S. L., Szymanowski, J. E. S., Gao, Y., Liu, T., Burns, P. C., Fein, J. B.: Experimental measurements of U60 nanocluster stability in aqueous solution. Geochemica et Cosmochimica Acta 156, 94-105 (2015)]. In this study, we measured the aqueous stability of a second uranyl peroxide nanocluster, U24Py (Na{sub 30}[(UO{sub 2}){sub 24}(O{sub 2}){sub 24}(HP{sub 2}O{sub 7}){sub 6}(H{sub 2}P{sub 2}O{sub 7}){sub 6}]), in batch systems as a function of time, pH, and nanocluster concentration, and then compared the aqueous behavior of U24Py to U60 to determine whether the size and morphology differences result in differences in their aqueous behaviors. Systems containing U24Py nanoclusters took over 30 days to achieve steady-state concentrations of monomeric U, Na, and P, illustrating slower reaction kinetics than parallel U60 systems. Furthermore, U24Py exhibited lower stability in solution than U60, with an average of 72% of the total mass in each nanocluster suspension being associated with the U24Py nanocluster, whereas 97% was associated with the U60 nanocluster in parallel experiments [Flynn, S. L., Szymanowski, J. E. S., Gao, Y., Liu, T., Burns, P. C., Fein, J. B.: Experimental measurements of U60 nanocluster stability in aqueous solution. Geochemica et Cosmochimica Acta 156, 94-105 (2015)]. The measurements from the batch experiments were used to calculate ion activity product (IAP) values for the reaction between the U24Py nanocluster and its constituent monomeric

Removal of boron from aqueous solution using cryptocrystalline magnesite

CSIR Research Space (South Africa)

Masindi, Vhahangwele

2016-05-01

Full Text Available of Water Reuse and Desalination Removal of boron from aqueous solution using cryptocrystalline magnesite Vhahangwele Masindi and Mugera W. Gitari Abstract The present study aimed to evaluate the efficiency of using cryptocrystalline magnesite...

Structure of water and the thermodynamics of aqueous solutions

Energy Technology Data Exchange (ETDEWEB)

Nemethy, G.

1970-10-26

This report represents the summary of a series of lectures held at the Istituto Superiore di Sanita, Laboratori di Fisica, from 18 September to 26 October 1970. The topics discussed were: Intermolecular forces, the individual water molecule and the hydrogen bond, the structures of the solid phases of water, experimental information on the strucuture of liquid water, theoretical models of water structure, experimental properties and theoretical models of aqueous solutions of nonpolar solutes, polar solutes, and electrolytes, the conformational stability of biological macromolecules.

Theoretical approach to the destruction or sterilization of drugs in aqueous solution

International Nuclear Information System (INIS)

Slegers, Catherine; Tilquin, Bernard

2005-01-01

Two novel applications in the radiation processing of aqueous solutions of drugs are the sterilization of injectable drugs and the decontamination of hospital wastewaters by ionizing radiation. The parameters influencing the destruction of the drug in aqueous solutions are studied with a computer simulation program. This theoretical approach has revealed that the dose rate is the most important parameter that can be easily varied in order to optimize the destruction or the protection of the drug

Aqueous solution dispersement of carbon nanotubes

Science.gov (United States)

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

2011-01-01

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

Experimental measurements of U60 nanocluster stability in aqueous solution

Science.gov (United States)

Flynn, Shannon L.; Szymanowski, Jennifer E. S.; Gao, Yunyi; Liu, Tianbo; Burns, Peter C.; Fein, Jeremy B.

2015-05-01

In this study, the aqueous behavior of isolated U60 nanoclusters (K16Li25[UO2(O2)OH]60)-19 was studied under several pH conditions and nanocluster concentrations to determine if the nanoclusters exhibit solid phase buffering behavior or if they exhibit behavior more like aqueous complexes. U60 is a cage cluster consisting of 60 (UO2)(O2)2(OH)2 uranyl polyhedral which share OH and O2 groups with their neighboring uranyl polyhedral, resulting in negatively charged cage clusters whose charge is at least partially offset by K+ and Li+ in the aqueous phase. Batch experiments to monitor nanocluster stability were conducted for 16 days at pH 7.5, 8.0 and 8.5 at nanocluster suspension concentrations of 1.4, 2.8 and 6.0 g/L. The aqueous concentrations of U, Li, and K, determined after 10 kDa molecular weight filtration, achieved steady-state with the nanoclusters within 24 h. The steady-state aqueous U, Li, and K concentrations were independent of solution pH, however they increased with increasing nanocluster concentration, indicating that the nanoclusters do not buffer the aqueous activities as a bulk solid phase would, but exhibit behavior that is more characteristic of dissolved aqueous complexes. The ion activity product (I.A.P.) value was calculated using two approaches: (1) treating the nanoclusters as a solid phase with an activity of one, and (2) treating the nanoclusters as aqueous complexes with a non-unit activity equal to their concentration in solution. The I.A.P. values that were calculated with non-unit activity for the nanoclusters exhibited significantly less variation as a function of nanocluster concentration compared to the I.A.P. values calculated with a nanocluster activity of one. The results yield a calculated log dissociation constant for the U60 nanoclusters of 9.2 + 0.2/-0.3 (1σ). Our findings provide a better understanding of the thermodynamic stability and behavior of U60 nanoclusters in aqueous systems, and can be used to estimate the

Actinide removal from aqueous solution with activated magnetite

International Nuclear Information System (INIS)

Kochen, R.L.; Thomas, R.L.

1987-01-01

An actinide aqueous waste treatment process using activated magnetite has been developed at Rocky Flats. The use and effectiveness of various magnetites in lowering actinide concentrations in aqueous solution are described. Experiments indicate that magnetite particle size and pretreatment (activation of the magnetite surface with hydroxyl ions greatly influence the effective use of magnetite as an actinide adsorbent. With respect to actinide removal, Ba(OH) 2 -activated magnetite was more effective over a broader pH range than was NaOH-activated magnetite. About 50% less Ba(OH) 2 -activated magnetite was required to lower plutonium concentration from 10 -4 to 10 -8 g/l. 7 refs., 8 tabs

Degradation of Para-Phenylenediamine in Aqueous Solution by ...

African Journals Online (AJOL)

In this research Photo-Fenton Oxidation of Para-Phenylenediamine (PPD) in aqueous solution by UV/Fenton's reagent (Fe2+ and H2O2) was investigated. ... lower concentration of Phenylenediamines and UV-C assisted photo-Fenton showed that the photo-Fenton process was very effective than the normal Fenton process ...

Radiolysis of Aqueous Benzene Solutions

Energy Technology Data Exchange (ETDEWEB)

Christensen, H

1964-05-15

Aerated and deaerated aqueous solutions of benzene have been irradiated with {sup 60}Co {gamma}-rays. The products of radiolysis in deaerated, unbuffered or acid, solutions were phenol, biphenyl, hydrogen and in acid solutions also hydrogen peroxide with the following yields: G(phenol) = 0. 37 (0. 37), G(biphenyl) = 1.3 (1.7), G(H{sub 2}) = 0.44 (0. 43) and G(H{sub 2}O{sub 2}) = 0 (0.60), the figures in brackets giving the results for acid solutions. The results are shown to agree with the conclusion that k(e{sup -}{sub aq} + H{sub 2}O{sub 2}) >> k(H + H{sub 2}O{sub 2}). Furthermore, the results indicate that a competition takes place between the reactions: 2 C{sub 6}H{sub 6}OH {center_dot} -> dimer -> biphenyl. C{sub 6}H{sub 7} {center_dot} + C{sub 6}H{sub 6}OH {center_dot} -> dimer -> biphenyl. The yields in aerated, unbuffered or acid, solutions were: G(phenol) = 2.1 (2.3), G(biphenyl) = 0 (0), and G(H{sub 2}O{sub 2}) = 2.2 (3.1), the figures in brackets being valid for acid solutions. The ratio k(H + C{sub 6}H{sub 6})/k(H + O{sub 2}) was 1.4x10{sup -2}. The results indicate that peroxides, or more probably hydroperoxides, take part in the reactions. After the addition of Fe{sup 2+} or Fe{sup 3+} to aerated acid solutions G(phenol) was increased to 6.6 and 3.4 respectively. Oxygen was consumed more rapidly in the presence of Fe. Reaction mechanisms are discussed.

Ultrafast dynamics of hydrogen bond exchange in aqueous ionic solutions.

Science.gov (United States)

Park, Sungnam; Odelius, Michael; Gaffney, Kelly J

2009-06-04

The structural and dynamical properties of aqueous ionic solutions influence a wide range of natural and biological processes. In these solutions, water has the opportunity to form hydrogen bonds with other water molecules and anions. Knowing the time scale with which these configurations interconvert represents a key factor to understanding the influence of molecular scale heterogeneity on chemical events in aqueous ionic solutions. We have used ultrafast IR spectroscopy and Car-Parrinello molecular dynamics (CPMD) simulations to investigate the hydrogen bond (H-bond) structural dynamics in aqueous 6 M sodium perchlorate (NaClO4) solution. We have measured the H-bond exchange dynamics between spectrally distinct water-water and water-anion H-bond configurations with 2DIR spectroscopy and the orientational relaxation dynamics of water molecules in different H-bond configurations with polarization-selective IR pump-probe experiments. The experimental H-bond exchange time correlates strongly with the experimental orientational relaxation time of water molecules. This agrees with prior observations in water and aqueous halide solutions, and has been interpreted within the context of an orientational jump model for the H-bond exchange. The CPMD simulations performed on aqueous 6 M NaClO4 solution clearly demonstrate that water molecules organize into two radially and angularly distinct structural subshells within the first solvation shell of the perchlorate anion, with one subshell possessing the majority of the water molecules that donate H-bonds to perchlorate anions and the other subshell possessing predominantly water molecules that donate two H-bonds to other water molecules. Due to the high ionic concentration used in the simulations, essentially all water molecules reside in the first ionic solvation shells. The CPMD simulations also demonstrate that the molecular exchange between these two structurally distinct subshells proceeds more slowly than the H

Stabilizers of edaravone aqueous solution and their action mechanisms. 1. Sodium bisulfite

OpenAIRE

Tanaka, Masahiko; Sugimura, Natsuhiko; Fujisawa, Akio; Yamamoto, Yorihiro

2017-01-01

Edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one) has been used as a free radical scavenging drug for the treatment of acute ischemic stroke in Japan since 2001. Edaravone is given to patients intravenously; therefore, it is distributed in the form of an aqueous solution. However, aqueous solutions of edaravone are very unstable because it is present as edaravone anion, which is capable of transferring an electron to free radicals including oxygen, and becomes edaravone radical. We observed the...

Degradation of alachlor in aqueous solution by using hydrodynamic cavitation.

Science.gov (United States)

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.

Lanthanide complexation in aqueous solutions

International Nuclear Information System (INIS)

Choppin, G.R.

1984-01-01

The lanthanide elements form an extended series of cations with the same charge, slightly varying radii and useful magnetic and spectroscopic properties. Their use in technology is growing rapidly as their properties are more fully explored. The lanthanides also offer scientists valuable and often unique probes for investigating a variety of chemical and physical phenomena. This review has attempted to call attention to these latter uses without trying to provide a thorough discussion of all the relevant literature. Hopefully, awareness of the more interesting facets of present studies of lanthanide complexes in aqueous solution will spur even more advances in the use of these elements. (Auth.)

Solubility and viscosity for CO_2 capture process using MEA promoted DEAE aqueous solution

International Nuclear Information System (INIS)

Fu, Dong; Wang, LeMeng; Zhang, Pan; Mi, ChenLu

2016-01-01

Highlights: • Solubility of CO_2 in MEA promoted DEAE aqueous solution was measured. • Mass fraction and temperature dependences of solubility were illustrated. • Viscosities of carbonated MEA–DEAE solutions were measured and calculated. • Temperature, mass fraction and CO_2 loading dependences of viscosity were illustrated. - Abstract: The saturated solubility of CO_2 in monoethanolamine (MEA) promoted 2-diethylaminoethanol (DEAE) aqueous solution was investigated at temperatures ranging from (303.2 to 323.2) K. The mass fraction and temperature dependences of the saturated solubility and CO_2 loading are illustrated. The viscosities of both CO_2-unloaded and CO_2-loaded DEAE–MEA aqueous solutions were measured and then calculated by using the Weiland equation. The effects of temperature, mass fraction and CO_2 loading on viscosities are demonstrated.

Radiation resistance of organic azo dyes in aqueous solutions

International Nuclear Information System (INIS)

Khabarov, V.N.; Kozlov, L.L.

1987-01-01

The resistance to the action of the ionizing radiation of aqueous and aqueous-alcoholic solutions of organic mono- and diazo dyes was studied. The radiation chemical yield of decolorization of the dye, determined from the kinetic decolorization curves served as a quantitative criterion of the radiation resistance. The influence of pH, addition of ethanol, hydroquinone, thiourea, glucose and oxygen on the radiation resistance of the azo dyes was studied. An attempt was made to relate the efficiency of radiation decolorization to the chemical nature of the dye

DETERMINING PARAMETERS OF THE DIELECTRIC FUNCTION OF A SUBSTANCE IN AQUEOUS SOLUTION BY SELF-REFERENCED REFLECTION THZ SPECTROSCOPY

DEFF Research Database (Denmark)

2008-01-01

Method and apparatus for determining dielectric function of liquid solutions and thereby concentrations of substances in aqueous solution or the volatile/non-volatile nature of the liquid by self-referenced reflection THz spectroscopy. Having the aqueous solution in any container with a window al....... The invention is particularly useful for determining alcohol (ethanol) content in aqueous solution containing other substances and particles....

An introduction to radiation induced degradation of biological molecules in aqueous solutions

International Nuclear Information System (INIS)

Lal, Manohar

1991-01-01

Radiation chemistry of aqueous systems is the chemistry of H, OH, e aq - , H 3 O + and H 2 O * formed when a solute in aqueous solutions is exposed to ionising radiation. The pulse radiolysis technique has helped in the production, the detection and understanding of the reactions of primary species with solutes. A great deal of data on radiation biochemical studies e.g. degradation of DNA, its constituents and their protection, radiation protection and sensitisation, generation of superoxide ion and their reactions has already been reported but a great deal still needs to be done for the understanding of radiation biology. (author). 12 refs

Ammonia complexes of metals in aqueous solutions with high concentrations of ammonia

International Nuclear Information System (INIS)

Padar, T.G.; Novikov, L.K.; Stupko, T.V.; Isaev, I.D.; Pashkov, G.L.; Mironov, V.E.

1991-01-01

Potentiometric method, glass electrodes and Bierrum function were used to study the formation of ammonia complexes of magnesium, calcium, cadmium, zinc, copper(2) and silver in 2.0 mol/dm 3 aqueous solutions of ammonia nitrate with 0-18 mol/dm 3 ammonia concentrations at 25.0 deg C. Step constants of stability of studied complexes were calculated and their compositions were determined with account of nonideal character of aqueous-salt solutions with ammonia concentrations above 1.0 mol/dm 3 . Values of correction effects on salting out ammonia action for Bierrum function in solutions with 1.0-18 mol/dm 3 ammonia concentrations were found

Thermodynamics and Efficiency of a CuCl(aq)/HCl(aq) Electrolyzer

International Nuclear Information System (INIS)

Hall, Derek M.; Akinfiev, Nikolay N.; LaRow, Eric G.; Schatz, Richard S.; Lvov, Serguei N.

2014-01-01

The high ionic strength and complex speciation of the anolyte solution within the CuCl(aq)/HCl(aq) electrolytic cell have impeded predictions of the energy requirements for the cell's electrolytic reaction at 25 °C and 1 bar. After collecting experimental open circuit potential (OCP) data and comparing the values obtained with predictions from prospective thermodynamic models, an approach to predict thermodynamic values and the overall efficiency was formulated. The compositions of the experimental measurements ranged from 2-2.5 mol of CuCl(aq) with 8-9 mol of HCl(aq) per kilogram of water in anolyte solution and 8-9 mol of HCl(aq) per kilogram of water in catholyte solution. From the OCP data, it was found that activity coefficient and speciation effects were critical in predicting the Gibbs energy, entropy and thermodynamic (intrinsic maximum) efficiency of the electrolytic cell. At equilibrium, all thermodynamic functions of the anolyte redox reactions were the same after activity coefficients and speciation effects were taken into account. The electrochemical reactions’ Gibbs energy and entropy were found to be 9700 J/mol and 2.18 J/(mol K) at 25 °C and 1 bar, which indicated that the reactions required a small amount of electrical and thermal energy to proceed. With thermodynamic values for the electrolytic reaction and experimental data from a CuCl(aq)/HCl(aq) electrolytic cell, the voltage, current, thermodynamic and overall efficiency were calculated. The overall efficiency ranged from 15 to 95% depending on the current density

Efficient removal of Co(II) from aqueous solution by titanate sodium nanotubes

Institute of Scientific and Technical Information of China (English)

Dong-Mei Li; Ning Liu; Fei-Ze Li; Jia-Li Liao; Ji-Jun Yang; Bing Li; Yun-Ming Chen; Yuan-You Yang; Jin-Song Zhang; Jun Tang

2016-01-01

In this paper, a novel material for Co(II) adsorption, titanate sodium nanotubes (Na2Ti2O5-NTs) were synthesized and characterized, and then they were used to remove Co(II) from aqueous solution and compared with titanic acid nanotubes (H2Ti2O5-NTs) and potassium hexatitanate whiskers (K2Ti6O13). The results showed that the adsorption of Co(II) on the materials was dependent on pH values and was a spontaneous, endothermic process. Specifically, Na2Ti2O5-NTs exhibited much more efficient ability to adsorb Co(II) from aqueous solution, with the maximum adsorption capacity of 85.25 mg/g. Furthermore, Na2Ti2O5-NTs could selectively adsorb Co(II) from aque-ous solution containing coexisting ions (Na+, K+, Mg2+, and Ca2+). The results suggested that Na2Ti2O5-NTs were potential effective adsorbents for removal of Co(II) or cobalt-60 from wastewater.

A thermodynamic study of glucose and related oligomers in aqueous solution: Vapor pressures and enthalpies of mixing

DEFF Research Database (Denmark)

Cooke, S.A.; Jonsdottir, Svava Osk; Westh, Peter

2002-01-01

Vapor pressures above aqueous solutions of glucose and maltose at both 298.06 K and 317.99 K and vapor pressures above aqueous solutions of cellobiose, maltotriose, maltotetraose, and maltopentaose at 317.99 K have been measured. The excess enthalpies have been recorded for all of the above-menti...... in aqueous solution. This so-called transference principle is found to be of interest in furthering the discussion concerning the applicability of lattice-based models for solution theory....

Hg(II) removal from aqueous solutions by bacillus subtilis biomass

Energy Technology Data Exchange (ETDEWEB)

Wang, Xue Song; Li, Fei Yan; He, Wen; Miao, Hua Hua [Department of Chemical Engineering, Huaihai Institute of Technology, Lianyungang (China)

2010-01-15

The biosorption of Hg(II) from aqueous solutions using Bacillus subtilis biomass was investigated in this study. The adsorbent was characterized by FTIR. Various factors including solution pH, initial concentration of Hg(II), contact time, reaction temperature and ionic strength were taken into account and promising results were obtained. An initial solution pH of 5.0 was most favorable for Hg(II) removal. The kinetic data was also analyzed using pseudo first order and pseudo second order equations. The results suggested that Hg(II) bioadsorption was best represented by the pseudo second order equation. Freundlich, Langmuir and Langmuir-Freundlich isotherms for the present systems were analyzed. The most satisfactory interpretation for the equilibrium data at different temperatures was given by the Langmuir-Freundlich isotherm. The effect of ionic strength on bioadsorption was significant. Bacillus subtilis biomass could serve as low cost adsorbent to remove Hg(II) from aqueous solutions, especially at lower concentrations of Hg(II) (<20 mg Hg/L). (Abstract Copyright [2010], Wiley Periodicals, Inc.)

Deacidification of oils and fats of biological origine by aqueous solutions of tertiary amines*

Directory of Open Access Journals (Sweden)

Peter Siegfried

2001-01-01

Full Text Available Deacidification of triacylglycerols by extraction is investigated using aqueous solutions of amines as extractants. Tertiary amines with boiling points ranging between 100° and 170°C, such as 2-methylamino-diethanol, 2-dimethylamino-ethanol, 4-methylmorpholine, 1-dimethylamino-2-propanol etc. were found to be suitable substances. Especially the deacidification by aqueous solutions of 2-dimethylamino-ethanol (DMAE was amply investigated as it is used as an active agent in remedies. Amazingly gelatinous soap stocks are not formed, when the concentration of DMAE exceeds 20% if the free fatty acid content of the oil is below 15%. Two liquid phases are formed in systems composed of triacylglyceroles and aqueous solutions containing 20 to 80% DMAE. Palm oil containing 4.3 wt.% free fatty acids was mixed with an equal amount of an aqueous solution of 30 wt.% DMAE at 60°C. In equilibrium an extract containing 86 wt.% free fatty acids (solvents deducted and a raffinate of 0.09 wt.% free fatty acids are obtained. Loss of neutral oil being 0.7 wt.%.

Carbonised jackfruit peel as an adsorbent for the removal of Cd(II) from aqueous solution.

Science.gov (United States)

Inbaraj, B Stephen; Sulochana, N

2004-08-01

The fruit of the jack (Artocarpus heterophyllus) is one of the popular fruits in India, where the total area under this fruit is about 13,460 ha. A significant amount of peel (approximately 2,714-11,800 kg per tree per year) is discarded as agricultural waste, as apart from its use as a table fruit, it is popular in many culinary preparations. Treatment of jackfruit peel with sulphuric acid produced a carbonaceous product which was used to study its efficiency as an adsorbent for the removal of Cd(II) from aqueous solution. Batch experiments were performed as a function of process parameters; agitation time, initial metal concentration, adsorbent concentration and pH. Kinetic analyses made with Lagergren pseudo-first-order, Ritchie second-order and modified Ritchie second-order models showed better fits with modified Ritchie second-order model. The Langmuir-Freundlich (Sips equation) model best defined the experimental equilibrium data among the three isotherm models (Freundlich, Langmuir and Langmuir-Freundlich) tested. Taking a particular metal concentration, the optimum dose and pH required for the maximum metal removal was established. A complete recovery of the adsorbed metal ions from the spent adsorbent was achieved by using 0.01 M HCl.

Radiolysis of anthraquinone dyes in aqueous solutions

International Nuclear Information System (INIS)

Vysotskaya, N.A.; Bortun, L.N.; Ogurtsov, N.A.; Migdalovich, E.A.; Revina, A.A.; Volodko, V.V.; AN SSSR, Moscow. Inst. Ehlektrokhimii)

1986-01-01

The commercial anthraquinone dyes (Dark Blue, Light Blue, Green) in aqueous solutions were shown to be decoloured and degrade under the action of ionizing radiation. The degree of decolouration and degradation of aromatic rings was found to increase in presence of oxygen. Hydroxyl radicals were shown to play the key role in the degradation of the dyes under irradiation. The radiolysis intermediate products were studied using the pulse radiolysis technique. (author)

Ion spatial distributions at the liquid-vapor interface of aqueous potassium fluoride solutions

Energy Technology Data Exchange (ETDEWEB)

Brown, M A; D' Auria, R; Kuo, I W; Krisch, M J; Starr, D E; Bluhm, H; Tobias, D J; Hemminger, J C

2008-04-23

X-ray photoemission spectroscopy operating under ambient pressure conditions is used to probe ion distributions throughout the interfacial region of a free-flowing aqueous liquid micro-jet of 6 M potassium fluoride. Varying the energy of the ejected photoelectrons by carrying out experiments as a function of x-ray wavelength measures the composition of the aqueous-vapor interfacial region at various depths. The F{sup -} to K{sup +} atomic ratio is equal to unity throughout the interfacial region to a depth of 2 nm. The experimental ion profiles are compared with the results of a classical molecular dynamics simulation of a 6 M aqueous KF solution employing polarizable potentials. The experimental results are in qualitative agreement with the simulations when integrated over an exponentially decaying probe depth characteristic of an APPES experiment. First principles molecular dynamics simulations have been used to calculate the potential of mean force for moving a fluoride anion across the air-water interface. The results show that the fluoride anion is repelled from the interface, and this is consistent with the depletion of F{sup -} at the interface revealed by the APPES experiment and polarizable force field-based molecular dynamics simulation. Together, the APPES and MD simulation data provide a detailed description of the aqueous-vapor interface of alkali fluoride systems. This work offers the first direct observation of the ion distribution at a potassium fluoride aqueous solution interface. The current experimental results are compared to those previously obtained for saturated solutions of KBr and KI to underscore the strong difference in surface propensity between soft/large and hard/small halide ions in aqueous solution.

Opto-electrochemical spectroscopy of metals in aqueous solutions

International Nuclear Information System (INIS)

Habib, K.

2016-01-01

In the present investigation, holographic interferometry was utilized for the first time to determine the rate change of the electrical resistance of aluminium samples during the initial stage of anodisation processes in aqueous solution. In fact, because the resistance values in this investigation were obtained by holographic interferometry, electromagnetic method rather than electronic method, the abrupt rate change of the resistance was called electrical resistance–emission spectroscopy. The anodisation process of the aluminium samples was carried out by electrochemical impedance spectroscopy (EIS) in different sulphuric acid concentrations (1.0%–2.5% H 2 SO 4 ) at room temperature. In the meantime, the real time holographic interferometry was used to determine the difference between the electrical resistance of two subsequent values, dR, as a function of the elapsed time of the EIS experiment for the aluminium samples in 1.0%, 1.5%, 2.0%, and 2.5% H 2 SO 4 solutions. The electrical resistance–emission spectra of the present investigation represent a detailed picture of not only the rate change of the electrical resistance throughout the anodisation processes but also the spectra represent the rate change of the growth of the oxide films on the aluminium samples in different solutions. As a result, a new spectrometer was developed based on the combination of the holographic interferometry and electrochemical impedance spectroscopy for studying in situ the electrochemical behavior of metals in aqueous solutions.

Origin of supercharging in electrospray ionization of noncovalent complexes from aqueous solution.

Science.gov (United States)

Sterling, Harry J; Williams, Evan R

2009-10-01

The use of m-nitrobenzyl alcohol (m-NBA) to enhance charging of noncovalent complexes formed by electrospray ionization from aqueous solutions was investigated. Addition of up to 1% m-NBA can result in a significant increase in the average charging of complexes, ranging from approximately 13% for the homo-heptamer of NtrC4-RC (317 kDa; maximum charge state increases from 42+ to 44+) to approximately 49% for myoglobin (17.6 kDa; maximum charge state increases from 9+ to 16+). Charge state distributions of larger complexes obtained from heated solutions to which no m-NBA was added are remarkably similar to those containing small amounts of m-NBA. Dissociation of the complexes through identical channels both upon addition of higher concentrations of m-NBA and heating is observed. These results indicate that the enhanced charging upon addition of m-NBA to aqueous electrospray solutions is a result of droplet heating owing to the high boiling point of m-NBA, which results in a change in the higher-order structure and/or dissociation of the complexes. For monomeric proteins and small complexes, the enhancement of charging is lower for heated aqueous solutions than from solutions with m-NBA because rapid folding of proteins from heated solutions that do not contain m-NBA can occur after the electrospray droplet is formed and is evaporatively cooled.

[Extraction of lambda-cyhalothrin from aqueous dioxan solutions].

Science.gov (United States)

Shormanov, V K; Chigareva, E N; Belousova, O V

2011-01-01

The results of extraction of lambda-cigalotrin from dioxan aqueous solutions by hydrophobic organic solvents are presented. It is shown that the degree of extraction depends on the nature of the extractant, the water to dioxan ratio, and saturation of the water-dioxan layer with the electrolyte. The highest efficiency of lambda-cigalotrin extraction was achieved using chlorophorm as a solvent under desalination conditions. The extraction factor was calculated necessary to obtain the desired amount of lambda-cigalotrin from the water-dioxan solution (4:1) with the help of the extractants being used.

NMR study of thermoresponsive block copolymer in aqueous solution

Czech Academy of Sciences Publication Activity Database

Spěváček, Jiří; Konefal, Rafal; Čadová, Eva

2016-01-01

Roč. 217, č. 12 (2016), s. 1370-1375 ISSN 1022-1352 R&D Projects: GA ČR(CZ) GA15-13853S Institutional support: RVO:61389013 Keywords : aqueous solutions * NMR * NOESY Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.500, year: 2016

DETERMINATION OF CHLORHEXIDINE IN SALIVA AND IN AQUEOUS-SOLUTIONS

NARCIS (Netherlands)

de Vries, J.; Ruben, J; Arends, J.

1991-01-01

A new method is presented for the determination of chlorhexidine in centrifuged saliva and in aqueous solutions by means of fluorescence spectroscopy. The method relies on complex formation between chlorhexidine and eosin. The fluorescence value of the chlorhexidine-eosin system decreases with

Thermodynamic behavior of erythritol in aqueous solutions and in gelatine gels and its quantification

International Nuclear Information System (INIS)

Tyapkova, Oxana; Bader-Mittermaier, Stephanie; Schweiggert-Weisz, Ute

2013-01-01

Highlights: • Differential scanning calorimetry as a method to determine erythritol crystallization. • Determination of crystallization using solution enthalpy. • Erythritol crystallization influenced by area of air–water-interfaces. • DSC method is applicable for both aqueous solutions and gels. • Adaption of DSC method to other, more complex food matrices is possible. - Abstract: As crystallization of erythritol can cause a sandy mouth-feel in sugar-free products, strategies to avoid crystallization or adaption of food formulation should be elucidated. However, until now erythritol crystallization was only quantified in aqueous solutions, but not in model food systems. Differential scanning calorimetry (DSC) is a simple method for the quantification of phase transition in various systems. However, no methods for the quantification of crystallization from aqueous systems based on DSC have been published until now. In the present study DSC was found to be suitable for the quantification of crystallization using supersaturated aqueous solutions of erythritol and erythritol containing gelatine gels for the first time. The developed method was validated by comparing the crystallization values determined by gravimetric measurement of erythritol crystals and the values obtained by DSC. No significant differences (p < 0.05) have been obtained between the results of the two methods if an appropriate design of measurements was applied. Additionally, the method was adapted to gelatine gels to elucidate the transferability to model food systems. Hence, the method is suitable for quantification of the amount of erythritol crystals present in aqueous solutions and gels, respectively

The radiolytic reduction of mercuric chloride in aqueous sugar solutions

International Nuclear Information System (INIS)

Johnston, F.J.

1991-01-01

The reduction of HgCl 2 has been measured in Co-60 γ-irradiated aqueous glucose, fructose and sucrose solutions. G-values for reduction, G(R), are substantially greater than 6 molecules per 100 eV in all systems from 1% by weight sugar to greater than 50%. Chain reduction occurs in glucose and fructose solutions with maximum G(R) values of 18-20 molecules per 100 eV occurring at 24% (1.0 M) sugar. The results are consistent with a mechanism in which HgCl radicals react with the organic solute to produce chain propagating free radicals. A dose rate independence of the chain length, after a brief ''induction'' period, is explained in terms of a chain termination by the incorporation of HgCl in growing Hg 2 Cl 2 particles. Reduction of Ag(I) and Cu(II) in aqueous sucrose and fructose systems took place with G(R) < 6 indicating the absence of reaction chains in these cases. (author)

The vapour pressure of water as a function of solute concentration above aqueous solutions of fructose, sucrose, raffinose, erythritol, xylitol, and sorbitol

DEFF Research Database (Denmark)

Cooke, S.A.; Jonsdottir, Svava Osk; Westh, Peter

2002-01-01

The vapour pressure of water above an aqueous solution of sucrose at T = 298.06 K has been measured for 9 sucrose mole fractions up to 0.12. Vapour pressure measurements have also been made on aqueous solutions of meso-erythritol, xylitol, sorbitol, fructose, and raffinose at T = 317.99 K...

Pinning of phase separation of aqueous solution of hydroxypropylmethylcellulose by gelation

Science.gov (United States)

Kita, Rio; Kaku, Takeshi; Kubota, Kenji; Dobashi, Toshiaki

1999-08-01

Opalescence of the aqueous solution of hydroxypropylmethylcellulose (HPMC) induced by heating has been studied in terms of the phase diagram and the phase separation dynamics. The cloud point curve and the sol-to-gel transition curve intersected with each other at about 55 °C. Just above the cloud-point curve at which the spinodal curve has its minimum, a ring-like scattering pattern appeared corresponding to the spinodal decomposition. Temporal growth of the scattering function in the course of phase separation was studied by a time-resolved light scattering technique. The gelation pinned the phase separation (spinodal decomposition) of the aqueous HPMC solution.

Effect of the aqueous, acidic and alcoholic extract of dried leaves of Erythroxylum coca var. coca (coca in Trichophyton rubrum, Trichophyton mentagrophytes, Microsporum canis and Candida albicans in vitro

Directory of Open Access Journals (Sweden)

Medalit Luna-Vílchez

2017-06-01

Full Text Available Objective: To evaluate the effect of the aqueous, acidic and alcoholic extract of dried leaves of Erythroxylum coca var. coca (coca in Trichophyton rubrum (TR, Trichophyton mentagrophytes (TM, Microsporum canis (MC and Candida albicans (CA in vitro. Materials and methods: An experimental study which evaluated the presence or absence of fungal growth, and fungal growth rate from the seeding point, compared to fungal growth in Sabouraud Agar (SA using Siegel-Tukey and KruskalWallis tests (p<0.05. Results: The CA group showed a statistical difference (p<0.05 between the following groups: 99.9% ethanol vs. aqueous, 99.9% ethanol vs. 0.01M HCl, 99.9% ethanol vs. control, control vs. aqueous, 0.01M HCl vs. control. The TR group showed a statistical difference (p<0.05 between the following groups: 99.9% ethanol vs. 0.01M HCl, 99.9% ethanol vs. aqueous, 99.9% ethanol vs. control, 0.01M HCl vs. control. The TM group showed a statistical difference (p<0.05 between the following groups: 99.9% ethanol vs. 0.01M HCl, 99.9% ethanol vs. control, aqueous vs. acid, aqueous vs. control. The MC group showed a statistical difference (p<0.05 between the following groups: 99.9% ethanol vs. 0.01M HCl, 99.9% ethanol vs. control, aqueous vs. acid, aqueous vs. control. In all the cases, the results of the 0.01M HCl vs. aqueous group were not significant. Conclusions: The aqueous, acidic and alcoholic extracts have no effect on the growth of CA and TM, but the alcoholic extract has effects on the growth of TR and MC. In addition, there were differences in the growth rate of CA, TR and TM in the aqueous, acidic and alcoholic extracts compared to that in SA. However only TR, TM and MC showed differences in their growth rate in the alcoholic extract.

Biosorption of nickel (II) ions from aqueous solutions by tapioca peel ...

African Journals Online (AJOL)

Tapioca peel, waste from native tapioca starch industry in Thailand, was used for the biosorption of nickel from aqueous solution. The experimental parameter focuses on the influence of contact time, solution pH, initial concentration and temperature using batch experiments. The results indicated that the biosorption ...

Removal of fluoride ions from aqueous solution by waste mud

International Nuclear Information System (INIS)

Kemer, Baris; Ozdes, Duygu; Gundogdu, Ali; Bulut, Volkan N.; Duran, Celal; Soylak, Mustafa

2009-01-01

The present study was carried out to assess the ability of original waste mud (o-WM) and different types of activated waste mud which are acid-activated (a-WM) and precipitated waste mud (p-WM), in order to remove excess of fluoride from aqueous solution by using batch technique. The p-WM exhibited greater performance than the others. Adsorption studies were conducted as a function of pH, contact time, initial fluoride concentration, adsorbent concentration, temperature, etc. Studies were also performed to understand the effect of some co-existing ions present in aqueous solutions. Adsorption process was found to be almost independent of pH for all types of waste mud. Among the kinetic models tested for p-WM, pseudo-second-order model fitted the kinetic data well with a perfect correlation coefficient value of 1.00. It was found that the adequate time for the adsorption equilibrium of fluoride was only 1 h. Thermodynamic parameters including the Gibbs free energy (ΔG o ), enthalpy (ΔH o ), and entropy (ΔS o ) revealed that adsorption of fluoride ions on the p-WM was feasible, spontaneous and endothermic in the temperature range of 0-40 deg. C. Experimental data showed a good fit with the Langmuir and Freundlich adsorption isotherm models. Results of this study demonstrated the effectiveness and feasibility of WM for removal of fluoride ions from aqueous solution.

NIR spectroscopic properties of aqueous acids solutions.

Science.gov (United States)

Omar, Ahmad Fairuz; Atan, Hanafi; Matjafri, Mohd Zubir

2012-06-15

Acid content is one of the important quality attributes in determining the maturity index of agricultural product, particularly fruits. Despite the fact that much research on the measurement of acidity in fruits through non-destructive spectroscopy analysis at NIR wavelengths between 700 to 1,000 nm has been conducted, the same response towards individual acids is not well known. This paper presents NIR spectroscopy analysis on aqueous citric, tartaric, malic and oxalic solutions through quantitative analysis by selecting a set of wavelengths that can best be used to measure the pH of the solutions. The aquaphotomics study of the acid solutions has generated R² above 0.9 for the measurement of all acids. The most important wavelengths for pH are located at 918-925 nm and 990-996 nm, while at 975 nm for water.

Phytodegradation potential of bisphenolA from aqueous solution by Azolla Filiculoides.

Science.gov (United States)

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.

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

Science.gov (United States)

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.

Removal of phosphate and nitrate from aqueous solution using ...

African Journals Online (AJOL)

The aim of the present study was the removal of phosphate and nitrate by sodium alginate seagrass (Cymodocea rotundata) beads from aqueous solutions. The adsorption characteristics of phosphate and nitrate on the seagrass beads were optimized under different operational parameters like adsorbent dosage, initial ...

Demineralisation of a semianthracite char with molten salts/HCl

International Nuclear Information System (INIS)

Alfaro-Dominguez, M.; Sanchez Bajo, F.

2006-01-01

The effects of chemical heat treatments of a semianthracite char (AC) on the composition of the mineral fraction of the material are investigated. The starting char was first treated with a mixture of LiCl/KCl or LiCl/KCl/CaO at 743, 873 or 1173 K and the products obtained were then washed thoroughly with distilled water. A small fraction of these samples were treated with 10 -3 M HCl solution. The composition changes were studied by X-ray diffraction. The predominant mineral components initially present in the starting char are quartz, mullite, muscovite and/or kaolinite and oldhamite. The treatments of AC resulted in significant changes in the mineral fraction of the material, in particular when LiCl/KCl/CaO was used. In this case, spurrite, γ-calcium orthosilicate and gehlenite were formed, which were eliminated by treatment with 10 -3 M HCl solution

Demineralisation of a semianthracite char with molten salts/HCl

Energy Technology Data Exchange (ETDEWEB)

Alfaro-Dominguez, M. [Departamento de Electronica e Ingenieria Electromecanica, Escuela de Ingenierias Industriales, Universidad de Extremadura, Avda de Elvas s/n, 06071 Badajoz (Spain)]. E-mail: malfaro@unex.es; Sanchez Bajo, F. [Departamento de Electronica e Ingenieria Electromecanica, Escuela de Ingenierias Industriales, Universidad de Extremadura, Avda de Elvas s/n, 06071 Badajoz (Spain)

2006-06-30

The effects of chemical heat treatments of a semianthracite char (AC) on the composition of the mineral fraction of the material are investigated. The starting char was first treated with a mixture of LiCl/KCl or LiCl/KCl/CaO at 743, 873 or 1173 K and the products obtained were then washed thoroughly with distilled water. A small fraction of these samples were treated with 10{sup -3} M HCl solution. The composition changes were studied by X-ray diffraction. The predominant mineral components initially present in the starting char are quartz, mullite, muscovite and/or kaolinite and oldhamite. The treatments of AC resulted in significant changes in the mineral fraction of the material, in particular when LiCl/KCl/CaO was used. In this case, spurrite, {gamma}-calcium orthosilicate and gehlenite were formed, which were eliminated by treatment with 10{sup -3} M HCl solution.

Corrosion inhibition of aluminum with a series of aniline monomeric surfactants and their analog polymers in 0.5 M HCl solution

Directory of Open Access Journals (Sweden)

M.M. El-Deeb

2015-07-01

Full Text Available The inhibition effect of 3-(12-sodiumsulfonate dodecyloxy aniline monomeric surfactant (MC12 and its analog polymer Poly 3-(dodecyloxy sulfonic acid aniline (PC12 on the corrosion of aluminum in 0.5 M HCl solution was investigated using weight loss and potentiodynamic polarization techniques. The presence of these two compounds in 0.5 M HCl inhibits the corrosion of aluminum without modifying the mechanism of corrosion process. It was found that these inhibitors act as mixed-type inhibitors with anodic predominance as well as the inhibition efficiency increases with increasing inhibitor concentration, but decreases with raising temperature. Langmuir and Frumkin adsorption isotherms fit well with the experimental data. Thermodynamic functions for both dissolution and adsorption processes were determined. The obtained results from weight loss and potentiodynamic polarization techniques are in good agreement with contact angle measurements.

Acidities of Water and Methanol in Aqueous Solution and DMSO

Science.gov (United States)

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…

Adsorption of Pb(II) ions from aqueous solution using lignin from ...

African Journals Online (AJOL)

The adsorption of lead(II) ions from aqueous solution onto alkali lignin extracted from Hagenia abyssinica was investigated by electrochemical methods. The effect of solution pH, lignin dosage and contact time were investigated at room temperature in a batch system. Adsorption equilibrium was approached within 80 min.

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

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Hui Dong

2017-03-01

Full Text Available 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.

Fast heavy-ion radiation damage of glycine in aqueous solution

Energy Technology Data Exchange (ETDEWEB)

Nomura, Shinji [Department of Nuclear Engineering, Kyoto University, Kyoto 615-8530 (Japan); Tsuchida, Hidetsugu, E-mail: tsuchida@nucleng.kyoto-u.ac.jp [Department of Nuclear Engineering, Kyoto University, Kyoto 615-8530 (Japan); Quantum Science and Engineering Center, Kyoto University, Uji 611-0011 (Japan); Furuya, Ryosuke [Department of Nuclear Engineering, Kyoto University, Kyoto 615-8530 (Japan); Majima, Takuya; Itoh, Akio [Department of Nuclear Engineering, Kyoto University, Kyoto 615-8530 (Japan); Quantum Science and Engineering Center, Kyoto University, Uji 611-0011 (Japan)

2016-12-15

Fast heavy-ion radiolysis of biomolecules in aqueous solution is investigated for an atomistic understanding of radiation damage to normal cells during heavy-particle beam therapy. The smallest amino acid glycine was used as a model biomaterial. Microjets of aqueous glycine solutions under vacuum were irradiated with 4.0-MeV carbon ions corresponding to energies in the Bragg peak region. To understand the effects of the water environment on molecular damage, the yield of glycine dissociation was measured by secondary ion mass spectroscopy. The yield was significantly reduced relative to gas-phase glycine targets. This implies that the numerous water molecules surrounding a single glycine molecule act as a buffer that suppresses dissociation. This is an environmental effect similar to that observed for other biomolecular cluster targets.

Effect of temperature on the behavior of surface properties of alcohols in aqueous solution

Energy Technology Data Exchange (ETDEWEB)

Romero, Carmen M. [Facultad de Ciencias, Universidad Nacional de Colombia, Bogota (Colombia)], E-mail: cmromeroi@unal.edu.co; Jimenez, Eulogio [Facultade de Ciencias, Universidade da Coruna (Spain); Suarez, Felipe [Facultad de Ciencias, Universidad Nacional de Colombia, Bogota (Colombia)

2009-04-15

The influence of temperature on the behavior of surface properties of aqueous solutions has often been used to obtain information about solute structural effects on water. In this work, we present experimental results for surface tension of aqueous solutions of n-pentanol, n-hexanol, n-heptanol, and n-octanol at T = (283.15, 288.15, 293.15, 298.15, 303.15, and 308.15) K at several concentrations. The results were used to evaluate the limiting experimental slopes of surface tension with respect to mole fraction and the hydrophobicity constant of the Connors model at each temperature. The thermodynamic behavior of aqueous alcohol solutions is discussed in terms of the effect of the hydrocarbon chain on water structure. The temperature dependence of the limiting slopes of surface tension with respect to mole fraction, as well as the hydrophobicity constant derived from surface measurements, is interpreted in terms of alcohol hydration.

Effect of temperature on the behavior of surface properties of alcohols in aqueous solution

International Nuclear Information System (INIS)

Romero, Carmen M.; Jimenez, Eulogio; Suarez, Felipe

2009-01-01

The influence of temperature on the behavior of surface properties of aqueous solutions has often been used to obtain information about solute structural effects on water. In this work, we present experimental results for surface tension of aqueous solutions of n-pentanol, n-hexanol, n-heptanol, and n-octanol at T = (283.15, 288.15, 293.15, 298.15, 303.15, and 308.15) K at several concentrations. The results were used to evaluate the limiting experimental slopes of surface tension with respect to mole fraction and the hydrophobicity constant of the Connors model at each temperature. The thermodynamic behavior of aqueous alcohol solutions is discussed in terms of the effect of the hydrocarbon chain on water structure. The temperature dependence of the limiting slopes of surface tension with respect to mole fraction, as well as the hydrophobicity constant derived from surface measurements, is interpreted in terms of alcohol hydration

Electronic structure tautomerism, and mechanism of H-D exchange in imidazole aqueous solutions

International Nuclear Information System (INIS)

Borisov, Yu.A.; Vorob'eva, N.P.; Abronin, I.A.; Kolomiets, A.F.

1988-01-01

The imidazole electronic structure in a gaseous phase is studied taking into account the influence of solvation effects in aqueous solutions. Possible mechanisms of tautomeric transformations and H-D exchange reactions with water molecules are discussed. Using the quantum chemistry methods, it is shown that the intramolecular mechanism of imidazole isomerization in the gaseous phase and the aqueous solution is unprofitable, and the intermolecular mechanism can proceed through the stage of protonated and carbene form formation

Adsorption of ammonium dinitramide (ADN) from aqueous solutions. 1. Adsorption on powdered activated charcoal.

Science.gov (United States)

Santhosh, G; Venkatachalam, S; Ninan, K N; Sadhana, R; Alwan, S; Abarna, V; Joseph, M A

2003-03-17

Investigations on the adsorption of ammonium dinitramide (NH(4)N(NO(2))(2)) (ADN) from aqueous solutions on powdered activated charcoal (PAC) were carried out in order to find out an effective and easier method of separating ADN from aqueous solutions. The effectiveness of PAC in the selective adsorption of ADN from aqueous solutions of ADN (ADN-F) and ADN in presence of sulfate (SO(4)(2-)) and nitrate (NO(3)(-)) ions (ADN-PS) was examined and compared using batch and column methods. The adsorption process follows both Langmuir and Freundlich adsorption isotherms and the isotherm parameters for the models were determined. The observed data favor the formation of monolayer adsorption. The adsorption capacities were found to be 63.3, 119, 105.3 and 82 mg of ADN per g of PAC for ADN-F (batch), ADN-PS (batch), ADN-F (column) and ADN-PS (column), respectively. Break-through curves for ADN-F and ADN-PS were obtained for the optimization of separation of ADN from aqueous solutions. Elution curves were generated for the desorption of ADN from PAC using hot water as eluent. Copyright 2003 Elsevier Science B.V.

The Effectiveness of HCl and HF Cleaning of Si0.85Ge0.15 Surface

International Nuclear Information System (INIS)

Sun, Y

2008-01-01

The cleaning of Si 0.85 Ge 0.15 surfaces using HCl and HF solutions is studied using synchrotron radiation photoelectron spectroscopy. The HF solution is found to be effective in removing both the Si oxide and the Ge oxide while the HCl solution can only remove part of the Ge oxide. For samples treated with HF, four spectral components are needed to fit the Ge 3d photoemission spectra. One is the bulk component and the other three are attributed to the surface Ge atoms with mono-hydride, di-hydride and tri-hydride terminations, respectively

Biosorptive removal of cobalt (II) ions from aqueous solution by ...

African Journals Online (AJOL)

hope&shola

2010-11-29

Nov 29, 2010 ... chemical reaction, decay, adsorption and biodegradation. The presence of ... sted coffee (Dakiky et al., 2002), waste tea (Ahluwalia and Goyal, 2005) ..... green removal from aqueous solution by citric acid modified rice straw.

Utilization of fermentation waste (Corynebacterium glutamicum) for biosorption of Reactive Black 5 from aqueous solution

International Nuclear Information System (INIS)

Vijayaraghavan, K.; Yun, Yeoung-Sang

2007-01-01

A fermentation waste, Corynebacterium glutamicum, was successfully employed as a biosorbent for Reactive Black 5 (RB5) from aqueous solution. This paper initially studied the effect of pretreatment on the biosorption capacity of C. glutamicum toward RB5, using several chemical agents, such as HCl, H 2 SO 4 , HNO 3 , NaOH, Na 2 CO 3 , CaCl 2 and NaCl. Among these reagents, 0.1 M HNO 3 gave the maximum enhancement of the RB5 uptake, exhibiting 195 mg/g at pH 1 with an initial RB5 concentration of 500 mg/l. The solution pH and temperature were found to affect the biosorption capacity, and the biosorption isotherms derived at different pHs and temperatures revealed that a low pH (pH 1) and high temperature (35 deg. C) favored biosorption. The biosorption isotherm was well represented using three-parameter models (Redlich-Peterson and Sips) compared to two-parameter models (Langmuir and Freundlich models). As a result, high correlation coefficients and low average percentage error values were observed for three-parameter models. A maximum RB5 uptake of 419 mg/g was obtained at pH 1 and a temperature of 35 deg. C, according to the Langmuir model. The kinetics of the biosorption process with different initial concentrations (500-2000 mg/l) was also monitored, and the data were analyzed using pseudo-first and pseudo-second order models, with the latter describing the data well. Various thermodynamic parameters, such as ΔG o , ΔH o and ΔS o , were calculated, indicating that the present system was a spontaneous and endothermic process. The use of a 0.1 M NaOH solution successfully desorbed almost all the dye molecules from dye-loaded C. glutamicum biomass at different solid-to-liquid ratios examined

Adsorption of Chromium from Aqueous Solution Using Polyaniline

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Majid Riahi Samani

2011-10-01

Full Text Available New group of polymers have been synthesized that are conductive of electricity so they are called conducting polymers. One of the most conducting polymers is "polyaniline". In the present study, polyaniline was synthesized by oxidizing aniline monomer under strongly acidic conditions using potassium iodate as an initiator of oxidative polymerization. Synthesized polyaniline as a powder used as an adsorbent to remove chromium from aqueous solution. Experiments were conducted in batch mode with variables such as amount of polyaniline, chromium solution pH and adsorbtion isotherms. Due to presence of Cr (III in solution after using polyaniline, removal mechanism is the combination of surface adsorption and reduction. It seems that polyaniline reduces the Cr(VI to Cr(III and adsorbs the Cr(III and a part of remaining  Cr(VI. It is well known that nitrogen atom in compounds of amine derivative makes co-ordinate bond with positive charge of metals due to the presence of electron in sp3 orbital of nitrogen. The majority of total chromium removal  occurred at 30minute for polyaniline  and the optimum  time for  hexavalent chromium  removal was about 5 min. Polyaniline has the maximum total cheomiume removal at pH, 3-9. The maximum hexavalent chromium removal occurred at acidic pH for polyanilines. The equilibrium adsorption data for polyaniline fitted both Freundlich’s and Langmuir’s isotherms. This research shows that polyaniline can be used as an adsorbent  for removal chromium from aqueous solution.

Synthesis of 5'-CMP and 5'-dCMP in aqueous solution induced by low energy ions implantation

International Nuclear Information System (INIS)

Shi Huaibin; Shao Chunlin; Wang Xiangqin; Yu Zengliang

2001-01-01

Low energy N + ions produced by N 2 are accelerated and then introduced into aqueous solution to induce chemical reactions. This process avoids the need of a vacuum chamber and makes it possible to investigate the actions of low energy ions in aqueous solution. In order to explore prebiotic synthesis of nucleotide via reaction between low energy ions and aqueous solution under the primitive earth conditions, low energy N + is implanted into aqueous solution containing cytosine, D-ribose, D-2-deoxyribose and NH 4 H 2 PO 4 . It is confirmed that 5'-CMP and 5'-dCMP are produced by HPLC and 1 H-NMR analyses. The relation between yields of 5'-CMP and 5'-dCMP and irradiation time has been obtained

Electrocoagulation-Adsorption to Remove Anionic and Cationic Dyes from Aqueous Solution by PV-Energy

OpenAIRE

Castañeda-Díaz, J.; Pavón-Silva, T.; Gutiérrez-Segura, E.; Colín-Cruz, A.

2017-01-01

The cationic dye malachite green (MG) and the anionic dye Remazol yellow (RY) were removed from aqueous solutions using electrocoagulation-adsorption processes. Batch and continuous electrocoagulation procedures were performed and compared. Carbonaceous materials obtained from industrial sewage sludge and commercial activated carbons were used to adsorb dyes from aqueous solutions in column systems with a 96–98% removal efficiency. The continuous electrocoagulation-adsorption system was more ...

The coacervation of aqueous solutions of tetraalkylammonium halides

International Nuclear Information System (INIS)

Mugnier de Trobriand, Anne.

1979-09-01

The coacervation of aqueous solutions of tatraalkylammonium halides in the presence of not of inorganic halides and acids has been studied, considering thermodynamic and spectroscopic aspects. The importance of dispersion forces as well as forces resulting from hydrophobic hydration has been assessed. The analogy between these systems and anionic ion exchange resins has been shown especially for Uranium VI extraction [fr

Mutual diffusion of sodium hyaluranate in aqueous solutions

International Nuclear Information System (INIS)

Veríssimo, Luís M.P.; Valada, Teresa I.C.; Sobral, Abilio J.F.N.; Azevedo, Eduarda E.F.G.; Azevedo, Maria L.G.; Ribeiro, Ana C.F.

2014-01-01

Highlights: • Binary diffusion coefficients for the systems containing sodium hyaluronate. • Influence of the aggregation on diffusion of the sodium hyaluronate in the aqueous media. • Estimation of the thermodynamic and mobility factors from mutual diffusion. -- Abstract: The Taylor dispersion technique has been used for measuring mutual diffusion coefficients of sodium hyaluronate in aqueous solutions at T = 298.15 K, and concentrations ranging from (0.00 to 0.50) g · dm −3 . The results are interpreted on the basis of Nernst, and Onsager and Fuoss theoretical equations. From the diffusion coefficient at infinitesimal concentration, the limiting ionic conductivity and the tracer diffusion coefficient of hyaluronate ion were estimated. These studies have been complemented by molecular mechanics calculations

Excellent enhancement of corrosion properties of Fe–9Al–30Mn–1.8C alloy in 3.5% NaCl and 10% HCl aqueous solutions using gas nitriding treatment

Energy Technology Data Exchange (ETDEWEB)

Chen, Yung-Chang; Lin, Chih-Lung; Chao, Chuen-Guang; Liu, Tzeng-Feng, E-mail: Lewischen815@gmail.com

2015-06-05

Highlights: • The FeAlMnC alloy was gas-nitrided to simultaneously achieve the aging effect. • Anti-corrosion components AlN, Fe{sub 3}N and Fe{sub 4}N were identified by using GIXRD method. • The present nitrided alloy showed a great improvement in corrosion resistance. • The nitrided sample showed an excellent coherence between nitrided layer and matrix. • The nitrided and then stretched sample maintained satisfactory corrosion behavior. - Abstract: The as-quenched Fe–9.0Al–30Mn–1.8C (in wt.%) alloy gas nitrided at 550 °C for 4 h show excellent corrosion resistance investigated in 3.5% NaCl and 10% HCl solutions. Owing to the high corrosion resistance components, the gas-nitrided layer consists mainly of AlN with a slight amount of Fe{sub 3}N and Fe{sub 4}N identified by grazing incidence X-ray diffraction technique. Therefore, the pitting potential and corrosion potential of the nitrided sample are +1860 mV and +30 mV, respectively. Surprisingly, it is worthy to be pointed out that the nitrided and then tensile-tested alloy reveals very shallow in fracture depth and the excellent lattice coherence is shown between the nitrided layer and the substrate. Moreover, due to the extremely high nitrogen concentration (about 17–18 wt.%) at stretched surface, the corrosion resistance of present gas-nitrided and then tensile-tested alloy is superior to those optimally gas-nitrided or plasma-nitrided high-strength alloy steels, as well as martensitic stainless steels. The nitrided and then stretched alloy still retains a satisfactory corrosion resistance (E{sub pit} = +890 mV; E{sub corr} = +10 mV). Furthermore, only nanoscale-size pits were observed on the corroded surface after being immersed in 10% HCl for 24 h.

Removal of Pb(II) ions from aqueous solution by a waste mud from copper mine industry: equilibrium, kinetic and thermodynamic study.

Science.gov (United States)

Ozdes, Duygu; Gundogdu, Ali; Kemer, Baris; Duran, Celal; Senturk, Hasan Basri; Soylak, Mustafa

2009-07-30

The objective of this study was to assess the adsorption potential of a waste mud (WM) for the removal of lead (Pb(II)) ions from aqueous solutions. The WM was activated with NaOH in order to increase its adsorption capacity. Adsorption studies were conducted in a batch system as a function of solution pH, contact time, initial Pb(II) concentration, activated-waste mud (a-WM) concentration, temperature, etc. Optimum pH was specified as 4.0. The adsorption kinetic studies indicated that the overall adsorption process was best described by pseudo-second-order kinetics. The equilibrium adsorption capacity of a-WM was obtained by using Langmuir and Freundlich isotherm models and both models fitted well. Adsorption capacity for Pb(II) was found to be 24.4 mg g(-1) for 10 g L(-1) of a-WM concentration. Thermodynamic parameters including the Gibbs free energy (Delta G degrees), enthalpy (Delta H degrees), and entropy (DeltaS degrees) indicated that the adsorption of Pb(II) ions on the a-WM was feasible, spontaneous and endothermic, at temperature range of 0-40 degrees C. Desorption studies were carried out successfully with diluted HCl solutions. The results indicate that a-WM can be used as an effective and no-cost adsorbent for the treatment of industrial wastewaters contaminated with Pb(II) ions.

Removal of Pb(II) ions from aqueous solution by a waste mud from copper mine industry: Equilibrium, kinetic and thermodynamic study

International Nuclear Information System (INIS)

Ozdes, Duygu; Gundogdu, Ali; Kemer, Baris; Duran, Celal; Senturk, Hasan Basri; Soylak, Mustafa

2009-01-01

The objective of this study was to assess the adsorption potential of a waste mud (WM) for the removal of lead (Pb(II)) ions from aqueous solutions. The WM was activated with NaOH in order to increase its adsorption capacity. Adsorption studies were conducted in a batch system as a function of solution pH, contact time, initial Pb(II) concentration, activated-waste mud (a-WM) concentration, temperature, etc. Optimum pH was specified as 4.0. The adsorption kinetic studies indicated that the overall adsorption process was best described by pseudo-second-order kinetics. The equilibrium adsorption capacity of a-WM was obtained by using Langmuir and Freundlich isotherm models and both models fitted well. Adsorption capacity for Pb(II) was found to be 24.4 mg g -1 for 10 g L -1 of a-WM concentration. Thermodynamic parameters including the Gibbs free energy (ΔG o ), enthalpy (ΔH o ), and entropy (ΔS o ) indicated that the adsorption of Pb(II) ions on the a-WM was feasible, spontaneous and endothermic, at temperature range of 0-40 o C. Desorption studies were carried out successfully with diluted HCl solutions. The results indicate that a-WM can be used as an effective and no-cost adsorbent for the treatment of industrial wastewaters contaminated with Pb(II) ions.

Removal of Pb(II) ions from aqueous solution by a waste mud from copper mine industry: Equilibrium, kinetic and thermodynamic study

Energy Technology Data Exchange (ETDEWEB)

Ozdes, Duygu; Gundogdu, Ali; Kemer, Baris; Duran, Celal; Senturk, Hasan Basri [Department of Chemistry, Karadeniz Technical University, Faculty of Arts and Sciences, 61080 Trabzon (Turkey); Soylak, Mustafa, E-mail: soylak@erciyes.edu.tr [Department of Chemistry, Erciyes University, Faculty of Arts and Sciences, 38039 Kayseri (Turkey)

2009-07-30

The objective of this study was to assess the adsorption potential of a waste mud (WM) for the removal of lead (Pb(II)) ions from aqueous solutions. The WM was activated with NaOH in order to increase its adsorption capacity. Adsorption studies were conducted in a batch system as a function of solution pH, contact time, initial Pb(II) concentration, activated-waste mud (a-WM) concentration, temperature, etc. Optimum pH was specified as 4.0. The adsorption kinetic studies indicated that the overall adsorption process was best described by pseudo-second-order kinetics. The equilibrium adsorption capacity of a-WM was obtained by using Langmuir and Freundlich isotherm models and both models fitted well. Adsorption capacity for Pb(II) was found to be 24.4 mg g{sup -1} for 10 g L{sup -1} of a-WM concentration. Thermodynamic parameters including the Gibbs free energy ({Delta}G{sup o}), enthalpy ({Delta}H{sup o}), and entropy ({Delta}S{sup o}) indicated that the adsorption of Pb(II) ions on the a-WM was feasible, spontaneous and endothermic, at temperature range of 0-40 {sup o}C. Desorption studies were carried out successfully with diluted HCl solutions. The results indicate that a-WM can be used as an effective and no-cost adsorbent for the treatment of industrial wastewaters contaminated with Pb(II) ions.

Characterization of aqueous solution of cresol red as food irradiation dosimeter

International Nuclear Information System (INIS)

Khan, H.M.; Tabassum, S.; Wahid, M.S.

2009-01-01

Dilute aqueous solution of cresol red has been evaluated spectrophotometrically as possible gamma rays dosimeter. A 0.10 mM solution of cresol red was irradiated by gamma rays using a cobalt-60 radiation source. The absorbance spectra of the unirradiated and irradiated solutions were recorded using double beam scanning spectrophotometer. The absorbance of the solution before and after irradiation was measured at 434 nm (λ max ) as well as at other wavelengths (415, 448 and 470 nm). Various parameters, such as Absorbance (A), ΔA, %A, -log A and log A o /A i were plotted against radiation dose, in order to check the response of cresol red solution and its possible use as chemical dosimeter. The response plots of A, ΔA, and %A versus absorbed dose showed that the solution can be used as a radiation dosimeter in a dose range up to 0.82 kGy. Using response plots of -log A and log A o /A i , the useful dose range can be extended up to 1.65 kGy; which are useful dose ranges for food irradiation applications. Stability studies of cresol red solution at different light and temperature conditions for pre- and post-irradiated storage of the dosimetric solutions suggested that aqueous solution of cresol red is highly stable in dark, under fluorescence light and at room temperature up to 150 days (author)

Cast iron deterioration with time in various aqueous salt solutions

Indian Academy of Sciences (India)

Unknown

various aqueous salt solutions have been carried out using total immersion test ... circuit potential, Icorr, Tafel slopes, corrosion rate, have been calculated by standard methods. ..... Rao B V S 1980 in Maintenance for reliability (Bombay: Media.

The kinetics of anodic dissolution of rhenium in aqueous electrolyte solutions

International Nuclear Information System (INIS)

Atanasyants, A.G.; Kornienko, V.A.

1986-01-01

The kinetics of anodic rhenium dissolution was investigated by means of potentiodynamic and potentiostatic polarization curves recorded at temperature from 293 to 333 K in different media (NaOH, KOH, NaCl, NaBr, HCl, H 2 SO 4 ) using the rotating disc technique. It is shown that the kinetics of anodic rhenium dissolution and effective activation energy depend not only on the composition and pH value of the solutions but also on the structure of the dissolving rhenium surface. The investigation of the anodic behaviour of the rhenium monocrystal revealed the existence of anisotropy of the monocrystal electrochemical properties. The experimental results point to an important role of adsorption processes in anodic rhenium dissolution. Rhenium dissolution proceeds with formation of intermediate surface adsorption complexes between the metal and the components of the solution

On reactions of polymerization of p-element hydroxides in aqueous solutions

International Nuclear Information System (INIS)

Tikavyj, V.F.; Lesnikovich, A.I.

1978-01-01

The tendency of p-element hydroxides towards polymerization in aqueous solutions has been considered with respect to their location in the Periodic Table. Stable hydroxides of d-elements are practically all polymerized; among s-elements only berillium and magnesium hydroxides polymerize as the least dissociated ones. Hydroxides of the elements located to the right of the 4 Group and above the 5-th Period do not polymerize in aqueous solutions. The structure and tendency towards polymerization of In, Te, and I compounds have been studied. The tendency to polymerization of all hydroxides of p-elements located below the 4-th Period is explained from the standpoint of electron structure and the simplest thermodynamic analysis (entropy, enthalpy)

Biosorption of strontium ions from aqueous solution using Ca-alginate biopolymer beads

International Nuclear Information System (INIS)

Goek, C.; Aytas, S.; Gerstmann, U.

2009-01-01

Biosorption of strontium ions from aqueous solution onto calcium alginate biopolymer beads was investigated in a batch system. Ca-alginate biopolymer beads were prepared from Na-alginate via cross-linking with divalent calcium ions according to the egg box model. Optimum biosorption conditions were determined as a function of initial solution pH, initial Sr concentration, contact time, biomass dosage and temperature. Langmuir, Freundlich and Dubinin-Radushkevich (D-R) models were applied to describe the biosorption isotherm of Sr ions by Ca-alginate biopolymer beads. The thermodynamic parameters (ΔH, ΔS, ΔG) for Sr sorption onto biosorbent were also determined from the temperature dependence. The results indicate that this biosorbent has a good potential for removal of Sr ions from dilute aqueous solution.

Transitions in aqueous solutions of sucrose at subzero temperatures

Czech Academy of Sciences Publication Activity Database

Sikora, Antonín; Dupanov, V. O.; Kratochvíl, Jaroslav; Zámečník, J.

2007-01-01

Roč. 46, č. 1 (2007), s. 71-85 ISSN 0022-2348 R&D Projects: GA ČR(CZ) GA522/04/0384 Institutional research plan: CEZ:AV0Z40500505 Keywords : aqueous sucrose solutions * subzero temperature * glass transitions Subject RIV: BJ - Thermodynamics Impact factor: 0.809, year: 2007

Absorption capacity and viscosity for CO_2 capture process using high concentrated PZ-DEAE aqueous solution

International Nuclear Information System (INIS)

Fu, Dong; Wang, LeMeng; Mi, ChenLu; Zhang, Pan

2016-01-01

Highlights: • Absorption of CO_2 in high concentrated DEAE-PZ aqueous solutions were measured. • Viscosities of CO_2-unloaded and CO_2-loaded DEAE-PZ aqueous solutions were measured. • Weiland equation was used to calculate the viscosities. • Effects of temperature, concentration and CO_2 loading on viscosity were demonstrated. - Abstract: The absorption capacity of CO_2 in piperazine (PZ) promoted 2-diethylaminoethanol (DEAE) aqueous solution was measured. The viscosities of both CO_2-unloaded and CO_2-loaded PZ-DEAE aqueous solutions were measured and then modelled. The temperatures ranged from 303.2 K to 323.2 K. The mass fraction of PZ and DEAE respectively ranged from 0 to 0.075 and 0.3 to 0.5. The temperature and concentration dependences of absorption capacity were determined. The effects of temperature, mass fraction and CO_2 loading on viscosities are demonstrated.

Separation of cesium from aqueous solutions using alkylated tetraaryl borates

International Nuclear Information System (INIS)

Feldmaier, F.

1991-01-01

The water solubility of cesium tetraaryl borates was lowered by introducing hydrophobic aliphatic side chains into corresponding acid-resistant fluorosubstituted tetraaryl borates. This improved cesium spearability both in precipitation and in extraction from aqueous solutions. (orig.) [de

(CI 42053) from an aqueous solution using Azadirachta indica leaf

African Journals Online (AJOL)

STORAGESEVER

2008-11-05

Nov 5, 2008 ... ... 42053) from an aqueous solution using Azadirachta indica leaf powder as a low- ... and biodegradable effective adsorbents. They were ob- tained from ... pesticide. The trees are also known as an air purifier. The medicinal.

Recovery of Ionic Liquids from aqueous solution by Nanofiltration

OpenAIRE

Fernández Dámaso, José Francisco

2011-01-01

The T-SAR methodology was combined with membrane characterization methods. An application of the combined approach was demonstrated with two commercial nanofiltration membranes and it was possible to successfully predict their performance for the recovery of ionic liquids from aqueous solution. Using model solutions of Pyr16 (CF3SO2)2N, it could be evidenced the formation of a new phase of ionic liquid during the concentration process. In this case, 66% of the ionic liquid was separated and t...

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

Science.gov (United States)

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.

Application of a cosmetic additive as an eco-friendly inhibitor for mild steel corrosion in HCl solution.

Science.gov (United States)

Liao, Liu Li; Mo, Shi; Lei, Jing Lei; Luo, Hong Qun; Li, Nian Bing

2016-07-15

The use of the cosmetic ingredient cocamidopropylamine oxide (CAO) to inhibit the corrosion of steel in 0.5mol/LHCl is investigated. Electrochemical and weight loss methods were used to evaluate the inhibiting effect of CAO and the influences of inhibitor concentration and temperature were determined. It was found that CAO acted as a mix-type inhibitor and was adsorbed chemically onto the steel in HCl solution, and the maximum inhibition efficiency was found at critical micelle concentration (CMC) of CAO in tested corrosive media. Moreover, it was speculated that relationships of the two adsorption sites of the inhibitor and steel surface were different. Copyright © 2016 Elsevier Inc. All rights reserved.

Sorption Potentials of Waste Tyre for Some Heavy Metals (Pb Cd in Aqueous Solution

Directory of Open Access Journals (Sweden)

Austin Kanayo ASIAGWU

2009-07-01

Full Text Available An investigation into the adsorption potential of activated and inactivated waste tyre powders for some heavy metals (Pb2+ and Cd2+ in their aqueous solution has been studied. The result indicated that inactivated waste tyre is a good non-conventional adsorbent for the removal of Cd from aqueous solution. A total of 93.3% of Cadmium contents was removed. The inactivated waste type proved a good adsorbent for the removal of Pb2+ 5g of 500mm activated tyre removed over 86.66% of Pb2+ from solution.

ISOCHORIC HEAT CAPACITY OF 1% AQUEOUS SOLUTION OF MAGNESIUM CHLORIDE

Directory of Open Access Journals (Sweden)

V. I. Dvoryanchikov

2016-01-01

Full Text Available Aim. The aim is to conduct an experimental study of isochoric heat capacity of 1% aqueous solution of magnesium chloride along the phase boundary curve.Method. In order to determine the isochoric heat capacity at the phase boundary curve we used the adiabatic calorimeter of KH. I. Amirkhanov.Results. Results of the study of the isochoric heat capacity depending on the temperature are given in tables and figures; the findings are compared with those of other researchers. When evaluating a complex system, we ought not to evaluate its effectiveness on the basis of only one criterion, even a very important, in this case must take into account the requirements of the technical, economic, environmental and of other natures.Conclusions. When solving optimization problems of efficiency in geothermal energy it is necessary to take into account the fact of the temperature dependence of the heat and density. The temperature dependence of the density and heat capacity in the calculations significantly affect the value of the efficiency criterion to be taken into account, otherwise the calculation error can be up to 20%. The data obtained from the isochoric heat capacity of aqueous solutions of magnesium chloride is compared with the data for water and aqueous solutions of NaCl and NaOH, obtained previously, which may be represented as a model of geothermal and sea water.

Removal of fluoride ions from aqueous solution by waste mud

Energy Technology Data Exchange (ETDEWEB)

Kemer, Baris; Ozdes, Duygu; Gundogdu, Ali; Bulut, Volkan N.; Duran, Celal [Karadeniz Technical University, Faculty of Arts and Sciences, Department of Chemistry, 61080 Trabzon (Turkey); Soylak, Mustafa, E-mail: soylak@erciyes.edu.tr [Erciyes University, Faculty of Arts and Sciences, Department of Chemistry, 38039 Kayseri (Turkey)

2009-09-15

The present study was carried out to assess the ability of original waste mud (o-WM) and different types of activated waste mud which are acid-activated (a-WM) and precipitated waste mud (p-WM), in order to remove excess of fluoride from aqueous solution by using batch technique. The p-WM exhibited greater performance than the others. Adsorption studies were conducted as a function of pH, contact time, initial fluoride concentration, adsorbent concentration, temperature, etc. Studies were also performed to understand the effect of some co-existing ions present in aqueous solutions. Adsorption process was found to be almost independent of pH for all types of waste mud. Among the kinetic models tested for p-WM, pseudo-second-order model fitted the kinetic data well with a perfect correlation coefficient value of 1.00. It was found that the adequate time for the adsorption equilibrium of fluoride was only 1 h. Thermodynamic parameters including the Gibbs free energy ({Delta}G{sup o}), enthalpy ({Delta}H{sup o}), and entropy ({Delta}S{sup o}) revealed that adsorption of fluoride ions on the p-WM was feasible, spontaneous and endothermic in the temperature range of 0-40 deg. C. Experimental data showed a good fit with the Langmuir and Freundlich adsorption isotherm models. Results of this study demonstrated the effectiveness and feasibility of WM for removal of fluoride ions from aqueous solution.

The Impact of HCl Precleaning and Sulfur Passivation on the Al2O3/Ge Interface in Ge Metal-Oxide-Semiconductor Capacitors

International Nuclear Information System (INIS)

Xue Bai-Qing; Chang Hu-Dong; Sun Bing; Wang Sheng-Kai; Liu Hong-Gang

2012-01-01

Surface treatment for Ge substrates using hydrogen chlorine cleaning and chemical passivation are investigated on AuTi/Al 2 O 3 /Ge metal-oxide-semiconductor capacitors. After hydrogen chlorine cleaning, a smooth Ge surface almost free from native oxide is demonstrated by atomic force microscopy and x-ray photoelectron spectroscopy observations. Passivation using a hydrogen chlorine solution is found to form a chlorine-terminated surface, while aqueous ammonium sulfide pretreatment results in a surface terminated by Ge-S bonding. Compared with chlorine-passivated samples, the sulfur-passivated ones show less frequency dispersion and better thermal stability based on capacitance-voltage characterizations. The samples with HCl pre-cleaning and (NH 4 ) 2 S passivation show less frequency dispersion than the HF pre-cleaning and (NH 4 ) 2 S passivated ones. The surface treatment process using hydrogen chlorine cleaning followed by aqueous ammonium sulfide passivation demonstrates a promising way to improve gate dielectric/Ge interface quality. (condensed matter: structure, mechanical and thermal properties)

Preferential adsorption of uranium ions in aqueous solutions by polymers

International Nuclear Information System (INIS)

Sakuragi, Masako; Ichimura, Kunihiro; Fujishige, Shoei; Kato, Masao

1981-01-01

Amidoxime fiber and triazine fiber were prepared by chemical modification of commercially available polyacrylonitril fiber. It was found that the Amidoxime fiber is efficient to adsorb uranium ions in the artificial sea water. The efficiency of the preferential adsorption decreases by treatment the material with an acid-or an alkaline-solution. The triazine fiber adsorbs uranium ions only in aqueous solutions of such uranyl acetate, in the absence of other ions. In the artificial sea water, it adsorbs other ions instead of uranium. The preferential adsorption of uranium ions was further investigated with a series of polystyrenesulfonamides. Among the polystyrene derivatives, those having carboxyl groups, derived from imino diacetic acid (PSt-Imi), β-alanine (PSt-Ala), glycine (PSt-Gly), and sarcosine (PSt-Sar) were qualified for further discussion. However, it was found that the amount of adsorption of uranium ions by PSt-Imi decreases with increasing the volume of the artificial sea water and/or the duration of the treatment. Taking into account the facts, the preferential adsorption of uranium ions by PSt-Imi in aqueous solution was discussed in detail. (author)

Removal of Cholera Toxin from Aqueous Solution by Probiotic Bacteria

Directory of Open Access Journals (Sweden)

Jussi A. O. Meriluoto

2012-06-01

Full Text Available Cholera remains a serious health problem, especially in developing countries where basic hygiene standards are not met. The symptoms of cholera are caused by cholera toxin, an enterotoxin, which is produced by the bacterium Vibrio cholerae. We have recently shown that human probiotic bacteria are capable of removing cyanobacterial toxins from aqueous solutions. In the present study we investigate the ability of the human probiotic bacteria, Lactobacillus rhamnosus strain GG (ATCC 53103 and Bifidobacterium longum 46 (DSM 14583, to remove cholera toxin from solution in vitro. Lactobacillus rhamnosus strain GG and Bifidobacterium longum 46 were able to remove 68% and 59% of cholera toxin from aqueous solutions during 18 h of incubation at 37 °C, respectively. The effect was dependent on bacterial concentration and L. rhamnosus GG was more effective at lower bacterial concentrations. No significant effect on cholera toxin concentration was observed when nonviable bacteria or bacterial supernatant was used.

Enzyme stabilization by glass-derived silicates in glass-exposed aqueous solutions

Science.gov (United States)

Ives, J.A.; Moffett, J.R.; Arun, P.; Lam, D.; Todorov, T.I.; Brothers, A.B.; Anick, D.J.; Centeno, J.; Namboodiri, M.A.A.; Jonas, W.B.

2010-01-01

Objectives: To analyze the solutes leaching from glass containers into aqueous solutions, and to show that these solutes have enzyme activity stabilizing effects in very dilute solutions. Methods: Enzyme assays with acetylcholine esterase were used to analyze serially succussed and diluted (SSD) solutions prepared in glass and plastic containers. Aqueous SSD preparations starting with various solutes, or water alone, were prepared under several conditions, and tested for their solute content and their ability to affect enzyme stability in dilute solution. Results: We confirm that water acts to dissolve constituents from glass vials, and show that the solutes derived from the glass have effects on enzymes in the resultant solutions. Enzyme assays demonstrated that enzyme stability in purified and deionized water was enhanced in SSD solutions that were prepared in glass containers, but not those prepared in plastic. The increased enzyme stability could be mimicked in a dose-dependent manner by the addition of silicates to the purified, deionized water that enzymes were dissolved in. Elemental analyses of SSD water preparations made in glass vials showed that boron, silicon, and sodium were present at micromolar concentrations. Conclusions: These results show that silicates and other solutes are present at micromolar levels in all glass-exposed solutions, whether pharmaceutical or homeopathic in nature. Even though silicates are known to have biological activity at higher concentrations, the silicate concentrations we measured in homeopathic preparations were too low to account for any purported in vivo efficacy, but could potentially influence in vitro biological assays reporting homeopathic effects. ?? 2009 The Faculty of Homeopathy.

Comparison Study On Sunlight Or Gamma Radiation Aging Resistance Of Poly (Vinyl Pyrrolidone) Aqueous Solution With PVP Nanogel

International Nuclear Information System (INIS)

Doan Binh; Pham Thu Hong; Nguyen Nguyet Dieu; Nguyen Thanh Duoc

2011-01-01

Comparison study on sunlight or gamma-radiation aging resistance of poly (vinyl pyrrolidone) (PVP) aqueous solution with PVP nanogel at 0.5% was carried out. Sunlight or gamma- radiation aging resistance of PVP aqueous solution and nanogel was evaluated on the basis of their intrinsic viscosity, UV-VIS absorbance, weight averaged molecular weight (M w ). The PVP aqueous solution and nanogel exposed to sunlight in the storage duration of 3 months and to gamma radiation at absorbed doses of 0, 15, 30, 50 kGy were used for this study. Furthermore, the stability of PVP nanogel and of PVP aqueous solution was also studied on the change of their intrinsic viscosity, UV-VIS absorbance, weight averaged molecular weight, particle size distribution and coil size. The experimental results were shown that the aging resistance of PVP nanogel was higher than that of PVP aqueous solution when exposed to gamma radiation or sunlight. (author)

from an aqueous solution using Azadirachta indica leaf powder

African Journals Online (AJOL)

Azadirachta indica (neem) leaf powder was used as an adsorbent for the removal of textile dye from aqueous solution. The adsorption of dye on A. indica was found to be dependent on contact time, dye concentration and amount of adsorbent. Spectrophotometric technique was used for the measurement of concentration of ...

Adsorption of tannic acid from aqueous solution onto surfactant-modified zeolite

Energy Technology Data Exchange (ETDEWEB)

Lin, Jianwei, E-mail: jwlin@shou.edu.cn [College of Marine Science, Shanghai Ocean University, No. 999 Hucheng Huan Road, Pudong District, Shanghai 201306 (China); Zhan, Yanhui; Zhu, Zhiliang [State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092 (China); Xing, Yunqing [College of Marine Science, Shanghai Ocean University, No. 999 Hucheng Huan Road, Pudong District, Shanghai 201306 (China)

2011-10-15

Graphical abstract: Surfactant-modified zeolites (SMZs) with various loadings of cetylpyridinium bromide (CPB) were used as adsorbents to remove tannic acid (TA) from aqueous solution. Highlights: {yields} Surfactant modified zeolites (SMZs) have a good tannic acid (TA) adsorption capacity. {yields} Adsorption capacity for SMZ with bilayer was relatively high at solution pH 3.5-7.0. {yields} Adsorption was well described by pseudo-second-order kinetic model. {yields} Adsorption fitted well with Langmuir, Redlich-Peterson and Sips isotherm models. {yields} Coexisting Cu(II) in aqueous solution resulted in markedly enhanced TA adsorption. - Abstract: Surfactant-modified zeolites (SMZs) with various loadings of cetylpyridinium bromide (CPB) were used as adsorbents to remove tannic acid (TA) from aqueous solution. The TA adsorption efficiencies for natural zeolite and various SMZs were compared. SMZ presented higher TA adsorption efficiency than natural zeolite, and SMZ with higher loading amount of CPB exhibited higher TA adsorption efficiency. The adsorption of TA onto SMZ as a function of contact time, initial adsorbate concentration, temperature, ionic strength, coexisting Cu(II) and solution pH was investigated. The adsorbents before and after adsorption were characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), thermogravimetric analysis (TGA), and Fourier transform infrared (FT-IR) spectroscopy. The adsorption kinetics of TA onto SMZ with CPB bilayer coverage (SMZ-CBC) followed a pseudo-second-order model. The equilibrium adsorption data of TA onto SMZ-CBC were well represented by Langmuir, Redlich-Peterson and Sips isotherm models. The calculated thermodynamic parameters indicated that TA adsorption onto SMZ-CBC was spontaneous and exothermic. The TA adsorption capacity for SMZ-CBC slightly decreased with increasing ionic strength but significantly increased with increasing Cu(II) concentration. The TA adsorption

Rapid synthesis of CdSe nanocrystals in aqueous solution at room ...

Indian Academy of Sciences (India)

Administrator

Water-soluble thioglycolic acid-capped CdSe nanocrystals (NCs) were prepared in aqueous solu- tion at room temperature. We investigated the ... NCs dispersed in buffer solution (pH = 4⋅0). FTIR spectra were recorded on a ... the theory of acid-base equilibrium, the initial pH value of original solution determines the ...

Effect of liquid oil additive on lithium-ion battery ceramic composite separator prepared with an aqueous coating solution

Energy Technology Data Exchange (ETDEWEB)

Kim, Sang Woo [Division of Advanced Materials Engineering, Kongju National University, 1223–24, Cheonan-daero, Cheonan, Chungnam, 31080 (Korea, Republic of); Ryou, Myung-Hyun [Department of Chemical & Biological Engineering, Hanbat National University, 125, Dongseodaero, Yuseong-gu, Daejeon, 34158 (Korea, Republic of); Lee, Yong Min, E-mail: yongmin.lee@hanbat.ac.kr [Department of Chemical & Biological Engineering, Hanbat National University, 125, Dongseodaero, Yuseong-gu, Daejeon, 34158 (Korea, Republic of); Cho, Kuk Young, E-mail: kycho@hanyang.ac.kr [Department of Materials Science and Chemical Engineering, Hanyang University, 55, Hanyangdaehak-ro, Sangrok-gu, Ansan, Gyeonggi-do, 15588 (Korea, Republic of)

2016-08-05

Ceramic composite separators (CCSs) play a critical role in ensuring safety for lithium-ion batteries (LIBs), especially for mid- and large-sized devices. However, production of CCSs using organic solvents has some cost and environmental concerns. An aqueous process for fabricating CCSs is attractive because of its cost-effectiveness and environmental-friendliness because organic solvents are not used. The success of an aqueous coating system for LIBs is dependent upon minimizing moisture content, as moisture has a negatively impact on LIB performance. In this study, CCSs were fabricated using an aqueous coating solution containing Al{sub 2}O{sub 3} and an acrylic binder. Compared with polyethylene (PE) separators, CCSs coated with an aqueous coating solution showed improved thermal stability, electrolyte uptake, puncture strength, ionic conductivity, and rate capability. In addition, our new approach of introducing a small amount of an oily liquid to the aqueous coating solution reduced the water adsorption by 11.7% compared with coatings that do not contain the oily liquid additive. - Highlights: • Ceramic composite separator is fabricated using aqueous coating process. • Coated separator showed enhanced mechanical and thermal stability. • Liquid oil additive in coating solution reduce moisture reabsorption of separator. • Oil additive in aqueous coating solution does not deteriorate LIB performance.

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

Science.gov (United States)

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...

Gamma-radiolysis of aqueous solutions of methyl orange and chrysoidine

International Nuclear Information System (INIS)

Khabarov, V.N.; Kozlov, L.L.; Panchenkov, G.M.

1980-01-01

Radiation-chemical bleaching of azo dyes of methyl orange and chrysoidine in aqueous and aqueous-alcoholic solutions under the effect of γ-radiation of 60 Co is studied. The effect of different additions and pH value of medium upon radiolysis of azo dyes is investigated. Radiation-chemical yields of the bleaching are determined. Quantitative connection between the initial yields of water radiolysis products and radiation yields of the bleaching of azo dyes is established. On the basis of the results obtained the most probable mechanism of methyl orange and chrysoidine bleaching is suggested

Electrochemical reactions of uranyl(VI) complexes in aqueous solution, non-aqueous solvents, and ionic liquids

International Nuclear Information System (INIS)

Ikeda, Yasuhisa

2006-01-01

Author's recent experimental results on the chemistry of U(V) in aqueous solution, non-aqueous solvents, and ionic solvents by cyclic voltametry are described. The U(V) was produced by electrochemical reduction of uranyl U(VI) ions or complexes such as carbonates, DMF(N, N-dimethylformamide), DMSO(dimethylsulfoxide), acetylacetonato, and other organic polydental ligands. The produced U(V) complexes were studied by spectrophotometry using optical-transmission thin-layer electrode. The U(V) complexes in non-aqueous solvents were found to be rather stable, they undergo ligand-dissociation reaction but not disproportionation reaction. The structure and electronic spectra as well as IR spectra of the complexes were studied. The present method was further developed to study the behavior of U(V) complexes in ionic liquids as molten salts, e.g., alkaline metals chlorides. Thus, the present research contributes to understanding the chemistry of 5fl system. Application to such nuclear technology as spent fuel reprocessing is discussed. (S. Ohno)

Examination of rheological properties of aqueous solutions of sodium caseinate

OpenAIRE

Jolanta Gawałek; Piotr Wesołowski

2012-01-01

Application of sodium caseinate as a functional additive in manufacturing processes requires production of its concentrated aqueous solutions which, in industrial conditions, presents a number of difficulties. In order to develop an effective and optimal industrial process of mixing – manufacturing a concentrated solution of sodium caseinate, it is essential to know rheological properties in a definite range of concentrations changing in the course of the dissolving process. The materia...

Pulse electrodeposition of Pt and Pt–Ru methanol-oxidation nanocatalysts onto carbon nanotubes in citric acid aqueous solutions

Energy Technology Data Exchange (ETDEWEB)

Chou, Huei-Yu [Department of Engineering and System Science, National Tsing Hua University, Hsinchu 30013, Taiwan, ROC (China); Hsieh, Chien-Kuo [Department of Materials Engineering, Ming Chi University of Technology, New Taipei City 24301, Taiwan, ROC (China); Tsai, Ming-Chi; Wei, Yu-Hsuan; Yeh, Tsung-Kuang [Department of Engineering and System Science, National Tsing Hua University, Hsinchu 30013, Taiwan, ROC (China); Tsai, Chuen-Horng, E-mail: tsai@aec.gov.tw [Department of Engineering and System Science, National Tsing Hua University, Hsinchu 30013, Taiwan, ROC (China)

2015-06-01

In this study, platinum nanoparticle/carbon nanotube (Pt NP/CNT) and platinum–ruthenium nanoparticle (Pt–Ru NP/CNT) hybrid nanocatalysts were prepared by the pulse-electrodeposition method in different aqueous solutions containing citric acid (CA) or sulfuric acid (SA). The electrocatalytic properties of the Pt NP/CNT and Pt–Ru NP/CNT electrodes prepared using different aqueous solutions were investigated for methanol oxidation. The results show that the electrochemical mass activities of these hybrid nanocatalysts prepared in the CA aqueous solution were increased by factors of 1.46 and 2.77 for Pt NPs and Pt–Ru NPs, respectively, compared with those prepared in SA aqueous solutions using the same procedure. These increased mass activities are attributed to the CA playing dual roles as both a stabilizing agent and a particle size reducing agent in the aqueous solutions. The approach developed in this work enables further reductions in the particle sizes of noble-metal nanocatalysts. - Highlights: • Pulse-electrodeposition of Pt or Pt–Ru nanoparticles on carbon nanotubes • Carbon nanotubes used as a catalyst-supporting material • Citric acid used as reducing agent in the aqueous electrodeposition solutions • Electrochemical activity for methanol oxidation improved by a factor of 1.46 to 2.77.

Corrosion inhibition performance of 2,5-bis(4-dimethylaminophenyl)-1,3,4-oxadiazole for carbon steel in HCl solution: Gravimetric, electrochemical and XPS studies

Energy Technology Data Exchange (ETDEWEB)

Bouanis, M.; Tourabi, M.; Nyassi, A. [Laboratoire de Catalyse et de Corrosion des Matériaux (LCCM), Faculté des Sciences, Université Chouaib Doukkali, B.P. 20, M-24000 El Jadida (Morocco); Zarrouk, A. [LCAE-URAC 18, Faculty of Science, First Mohammed University, PO Box 717, M-60 000 Oujda (Morocco); Jama, C. [UMET-ISP, CNRS UMR 8207, ENSCL, Université Lille Nord de France, CS 90108, F-59652 Villeneuve d' Ascq Cedex (France); Bentiss, F., E-mail: fbentiss@gmail.com [Laboratoire de Catalyse et de Corrosion des Matériaux (LCCM), Faculté des Sciences, Université Chouaib Doukkali, B.P. 20, M-24000 El Jadida (Morocco); UMET-ISP, CNRS UMR 8207, ENSCL, Université Lille Nord de France, CS 90108, F-59652 Villeneuve d' Ascq Cedex (France)

2016-12-15

Highlights: • 2,5-Bis(4-dimethylaminophenyl)-1,3,4-oxadiazole is good corrosion inhibitor for carbon steel in 1 M HCl. • XPS analysis has provided the composition of adsorbed protective layer on the steel surface. • The adsorption of the investigated 1,3,4-oxadiazole is mainly due to chemisorption. - Abstract: Corrosion inhibition of carbon steel in normal hydrochloric acid solution at 30 °C by 2,5-bis(4-dimethylaminophenyl)-1,3,4-oxadiazole (DAPO) has been studied by weight loss measurements and electrochemical techniques (polarization and AC impedance). The experimental results showed that DAPO acted as an efficient inhibitor against the carbon steel corrosion in 1 M HCl, and its inhibition efficiency increased with the inhibitor concentration reaching a value up to 93% at 1 mM. Polarization studies showed that the DAPO was a mixed-type inhibitor. The adsorption of this 1,3,4-oxadiazole derivative on the carbon steel surface in 1 M HCl solution followed the Langmuir adsorption isotherm and the corresponding value of the standard Gibbs free energy of adsorption (ΔG°{sub ads}) is associated to a chemisorption mechanism. Scanning Electron Microscopy (SEM) and X-Ray Photoelectron Spectroscopy (XPS) analyses were carried out to characterize the chemical composition of the inhibitive film formed on the steel surface. The surfaces studies showed that the inhibitive layer is composed of an iron oxide/hydroxide mixture where DAPO molecules are incorporated. The cytotoxicity of DAPO was also determined using cell culture system.

WHATIF-AQ, Geochem Speciation and Saturation of Aqueous Solution

International Nuclear Information System (INIS)

Nielsen, Ole John; Jensen, Bror Skytte

1988-01-01

1 - Description of program or function: WHATIF-AQ is part of a family of programs for calculations of geochemistry in the near-field of radioactive waste with temperature gradients. The program calculates speciation and saturation indices for an aqueous solution at temperatures in the range 0 - 125 degrees C. The chemical equilibrium is determined by solving a set of nonlinear equations consisting of the equilibrium constant and mass balance constraints. 2 - Method of solution: The set of equations is solved using a generalized Newton-Raphson technique

Comparative analysis of the effect of pretreating aspen wood with aqueous and aqueous-organic solutions of sulfuric and nitric acid on its reactivity during enzymatic hydrolysis

DEFF Research Database (Denmark)

Dotsenko, Gleb; Osipov, D. O.; Zorov, I. N.

2016-01-01

The effect of aspen wood pretreatment methods with the use of both aqueous solutions of sulfuric and nitric acids and aqueous-organic solutions (ethanol, butanol) of sulfuric acid (organosolv) on the limiting degree of conversion of this type of raw material into simple sugars during enzymatic...

Pulse radiolysis of pyridine and methylpyridines in aqueous solutions

DEFF Research Database (Denmark)

Solar, S.; Getoff, N.; Sehested, K.

1993-01-01

The radicals formed from pyridine, 3-methylpyridine, 3,5-dimethylpyridine, 2,6-dimethylpyridine and 2,4,6-trimethylpyridine by attack of H, e(aq)-, OH and O.- in aqueous solutions were investigated by pulse radiolysis in the pH-range 1-13.8. The UV-vis. absorption spectra as well as the formation...

Accurate Description of Calcium Solvation in Concentrated Aqueous Solutions

Czech Academy of Sciences Publication Activity Database

Kohagen, Miriam; Mason, Philip E.; Jungwirth, Pavel

2014-01-01

Roč. 118, č. 28 (2014), s. 7902-7909 ISSN 1520-6106 R&D Projects: GA ČR GBP208/12/G016; GA MŠk LH12001 Institutional support: RVO:61388963 Keywords : calcium chloride * aqueous solution * molecular dynamics * neutron scattering Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.302, year: 2014

The immiscible aqueous solutions of alkyl phosphates. Study for the purpose of uranium extraction from phosphoric acid solutions

International Nuclear Information System (INIS)

Mauborgne, Bernard

1979-01-01

Systems of immiscible aqueous solutions composed by a phase rich in mineral salt and by another phase almost totally containing an organic salt, have been studied for years, with quaternary ammonium salts with an organic cation. The objective of this research is to study systems symmetric to the previous ones, i.e. with organic anions such as alkyl phosphates, and then to try to understand mechanisms of extraction of metals in these environments. Based on properties of immiscible aqueous solutions, an original three-phase process of liquid-liquid extraction has been developed, and is used to separate uranium in phosphoric acids with better performance than the existing industrial processes [fr

Batch and column adsorption behaviors of Se(IV) and Te(IV) on organic and inorganic ion exchangers from HCl solutions

Energy Technology Data Exchange (ETDEWEB)

El-Sweify, Fatma H.; Abdel-Fattah, Alaa El-Din A.; Aly, Shorouk M.; Ghamry, Mohamed A. [Atomic Energy Authority, Cairo (Egypt). Hot Laboratories Center; El-Sheikh, Ragaa [Zagazig Univ. (Egypt). Chemistry Dept.

2017-07-01

Adsorption behaviors of Se(IV) and Te(IV) on the inorganic ion exchanger ceric tungstate (CeW) was studied under static and dynamic conditions and compared with the adsorption on the organic cation and anion exchangers Dowex-50X8 and AG-2X8, respectively. The radioactive isotopes {sup 75}Se and {sup 123m}Te were used to trace the respective elements. Some parameters affecting the adsorption were investigated under static conditions. In the case of batch technique the adsorption was studied from slightly acidic HCl as well as slightly alkaline media, i.e. at two pH-ranges. Se(IV) and Te(IV) were adsorbed on both the inorganic ion exchanger (CeW) and on AG-2X8, from slightly alkaline solutions. From the similarity of adsorption on both ion exchangers it was clear that (CeW) acts as an anion exchanger. Moreover, the obtained K{sub d}-values for the adsorption on (CeW) were much higher than those for the adsorption on the organic anion exchanger AG-2X8. Se(IV) was not adsorbed on Dowex-50X8 all over the studied pH-range whereas Te(IV) was slightly adsorbed. Loading and elution behaviors of Se(IV) and Te(IV) on columns of AG-2X8 and (CeW) were studied using solutions of HCl of different concentrations. Some good separation alternatives of Se(IV) and Te(IV) under certain conditions were achieved.

Pulse radiolysis studies of iron(I) in aqueous solutions

International Nuclear Information System (INIS)

Nenadovic, M.T.; Micic, O.I.; Muk, A.A.

1980-01-01

The absorption spectrum and decay kinetics of the products of the reactions of iron(II) ions with hydrated electrons and hydrogen atoms have been studied in aqueous solution using pulse-radiolysis techniques. Iron(I) is formed by reaction with hydrated electrons and its absorption spectrum is reported and discussed. The formation of molecular hydrogen by reaction of Fe + with water is suppressed by other solutes present in the solutions. In acidic solutions containing [SO 4 ] 2- , the intermediates formed in the reaction with H atoms decay by a first-order process and produce molecular hydrogen, but the rate of their decay does not depend only on the oxonium ion concentration but also on intermolecular rearrangement in the [FeSO 4 -H] complex. (author)

Cytosine modifications after gamma irradiation in aerated aqueous solution of Escherichia coli DNA

International Nuclear Information System (INIS)

Polverelli, M.

1983-04-01

After gamma irradiation of cytosine in aerated aqueous solution and utilization of various spectrometric methods (mass spectrometry, proton nuclear magnetic resonance and infrared spectrometry) about ten new radiolysis products were identified. The formation of N-glycolylbiuret in H 2 18 O aqueous solution of irradiated cytosine at pH 4,5 indicated that the preferred 18 OH hydroxyl radical attack was at C-5. The formation of trans 1-carbamoyl-4,5 dihydroxyimidazolidin-2 oxo which is the major product after cytosine pyrimidine ring rearrangement took place preferentially at neutral pH, while N-glycolylbiuret predominated at pH 4,5. The deamination pathway was predominant when cytosine was irradiated at acidic pH values (pH 2 ) or in copper complexes. The development of a new acid hydrolysis method using fluorhydric acid stabilized in pyridine made easier the evaluation of cytosine modifications after gamma irradiation in aerated aqueous solution of E. Coli DNA- 14 C-2 cytosine. This hydrolytic agent removed the modified bases from the polynucleotidic chain. A difference was found between the proportion of radiolytic products removed by acid hydrolysis and by irradiation of the free base in solution [fr

Application of modified multiwall carbon nanotubes as a sorbent for zirconium (IV) adsorption from aqueous solution

International Nuclear Information System (INIS)

Yavari, R.; Davarkhah, R.

2013-01-01

Modified multiwall carbon nanotubes (MWCNTs) by nitric acid solution were used to investigate the adsorption behavior of zirconium from aqueous solution. Pristine and oxidized MWCNTs were characterized using nitrogen adsorption/desorption isotherm, Boehm's titration method, thermogravimetry analysis, transmission electron microscopy and Fourier transform infrared spectroscopy. The results showed that the surface properties of MWCNTs such as specific surface area, total pore volume, functional groups and the total number of acidic and basic sites were improved after oxidation. These improvements are responsible for their hydrophobic properties and consequently an easy dispersion in water and suitable active sites for more adsorption of zirconium. The adsorption of Zr(IV) as a function of initial concentration of zirconium, contact time, MWCNTs dosage, HCl and HNO 3 concentration and also ionic strength was investigated using a batch technique under ambient conditions. The experimental results indicated that sorption of Zr(IV) was strongly influenced by zirconium concentrations, oxidized MWCNTs content and acid pH values. The calculated correlation coefficient of the linear regressions values showed that Langmuir model fits the adsorption equilibrium data better than the Freundlich model. Kinetic data of sorption indicated that equilibrium was achieved within 60 min and the adsorption process can be described by the pseudo second-order reaction rate model. Based on the experimental results, surface complexation is the major mechanism for adsorption of Zr(IV) onto MWCNTs. Also, Study on the desorption process of zirconium showed that the complete recovery can be obtained using nitric or hydrochloric acids of 4 M. (author)

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

Science.gov (United States)

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.

Characterization of aqueous solution of cresol red as food irradiation dosimeter

Energy Technology Data Exchange (ETDEWEB)

Khan, H M; Tabassum, S; Wahid, M S [Peshawar University, Peshawar (Pakistan). Radiation Chemistry Laboratory, National Centre of Excellence in Physical Chemistry

2009-06-15

Dilute aqueous solution of cresol red has been evaluated spectrophotometrically as possible gamma rays dosimeter. A 0.10 mM solution of cresol red was irradiated by gamma rays using a cobalt-60 radiation source. The absorbance spectra of the unirradiated and irradiated solutions were recorded using double beam scanning spectrophotometer. The absorbance of the solution before and after irradiation was measured at 434 nm ({lambda}{sub max}) as well as at other wavelengths (415, 448 and 470 nm). Various parameters, such as Absorbance (A), {delta}A, %A, -log A and log A{sub o}/A{sub i} were plotted against radiation dose, in order to check the response of cresol red solution and its possible use as chemical dosimeter. The response plots of A, {delta}A, and %A versus absorbed dose showed that the solution can be used as a radiation dosimeter in a dose range up to 0.82 kGy. Using response plots of -log A and log A{sub o}/A{sub i}, the useful dose range can be extended up to 1.65 kGy; which are useful dose ranges for food irradiation applications. Stability studies of cresol red solution at different light and temperature conditions for pre- and post-irradiated storage of the dosimetric solutions suggested that aqueous solution of cresol red is highly stable in dark, under fluorescence light and at room temperature up to 150 days (author)

The blue complexes of U in aqueous solutions

International Nuclear Information System (INIS)

Musikas, C.

1976-01-01

Mixed-valence uranium complexes were synthesized. Hydrolysis of hexavalent U leads to anionic species soluble in aqueous solutions when the UO 2 ++ ions are neutralized by tetraalkylammonium hydroxides. These complexes are polynuclear and the size and interatomic distances found for the polyanions are those of macromolecules. By hydrazine of these complexes, solutions were obtained and their absorption spectra studied. The spectra of U(VI) and U(V) ions are observed, together with new bands attributable to a charge transfer. It may be concluded that the blue complexes of uranium are type II composite-valence complexes for which the delocalization coefficient α can be calculated [fr

Quantitative Method for the Detection of Triethyl Phosphate in Aqueous Solutions

National Research Council Canada - National Science Library

Bagalawis, Rosa

2003-01-01

...) at the parts per million level in aqueous solution. TEP was used as a chemical agent simulant to evaluate the penetration characteristics of clothing, gloves, boots and items of personal equipment...

The kinetics of dye formation by pulse radiolysis of pararosaniline cyanide in aqueous or organic solution

International Nuclear Information System (INIS)

McLaughlin, W.L.; Holcman, J.; Sehested, K.; Kosanic, M.M.

1979-11-01

The radiation-induced conversion of the leucocyanide of pararosaniline dye to the highly colored salt-isomer of the dye in acidic aqueous solution (wavelength of maximum absorption lambda sub(max)=540 nm) or polar organic solution (lambda sub(max)=550 nm), takes place in two separate processes. The first is very fast (within 3 s -1 to 10 6 s -1 , as the acidity or concentration of an oxidizing agent increases. In oxygen-free acidic aqueous or organic solutions (argon saturated) there is an unstable transient species (lambdasub(max)=380 nm). When using O 2 or N 2 O-saturated aqueous or organic solution, there is no intermediate absorption band at 380 nm, but the slow process of dye formation at 540 or 550 nm is still sequential to the initial fast process having somewhat faster kinetics than in Ar-saturated solution. (author)

Removal of lead from aqueous solution on glutamate intercalated layered double hydroxide

Directory of Open Access Journals (Sweden)

Shen Yanming

2017-05-01

Full Text Available Glutamate intercalated Mg–Al layered double hydroxide (LDH was prepared by co-precipitation and the removal of Pb2+ in the aqueous solution was investigated. The prepared samples were characterized by XRD, FT-IR and SEM. It was shown that glutamate can intercalate into the interlayer space of Mg–Al LDH. The glutamate intercalated Mg–Al LDH can effectively adsorb Pb2+ in the aqueous solution with an adsorption capacity of 68.49 mg g−1. The adsorption of Pb2+ on glutamate intercalated Mg–Al LDH fitted the pseudo-second-order kinetics model and the isotherm can be well defined by Langmuir model.

Comparative study on heat pipe performance using aqueous solutions of alcohols

Energy Technology Data Exchange (ETDEWEB)

Senthilkumar, R.; Vaidyanathan, S.; Sivaraman, B. [Annamalai University, Department of Mechanical Engineering, Annamalai Nagar, Tamil Nadu (India)

2012-12-15

This paper deals with the performance characterization of heat pipes using an aqueous solution of long chain alcohols like n-Butanol, n-Pentanol, n-Hexanol and n-Heptanol as working mediums. These solutions are called as self-rewetting fluids, since these fluid mixtures possess a non-linear dependence of the surface tension with temperature. A cylindrical heat pipe made up of copper with two layers of wrapped screen is used as a wick material and partially filled with the self-rewetting fluid water mixture and tested for its heat transport capability like thermal efficiency and thermal resistance at different inclinations and input power levels. A number of tests have been performed with heat pipes, filled with various aqueous solutions of alcohols with a concentration of 2 ml/l in de-ionized water (DI water) on volume basis. The results obtained for heat pipes using self rewetting fluids show improved performances, when compared to DI water heat pipes. (orig.)

Study of free acidity determinations in aqueous solution; Etude des dosages d'acidite libre en solution aqueuse

Energy Technology Data Exchange (ETDEWEB)

Kergreis, A [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

1966-04-01

The object of this work is the study of the principal methods which can be applied to the measurement of 'free' acidity. In the first part, we define the various types of acidity which can exist in aqueous solution; then, after having studied some hydrolysis reactions, we compare the value of the neutralisation pH of the hydrated cation and that of the precipitation of the hydroxide. In the second part we have started to study the determination of the acidity of an aqueous solution. After having rapidly considered the 'total' acidity determination, we deal with the problem of the 'free' acidity titration. We have considered in particular certain methods: extrapolation of the equivalent point, colorimetric titrations with or without a complexing agent, and finally the use of ion-exchange resins with mixed aqueous and solvent solutions. (author) [French] Le but de ce travail est l'etude des principales methodes de determination de l'acidite 'libre'. Dans une premiere partie nous avons defini les differentes sortes d'acidites pouvant exister en solution aqueuse, puis apres avoir etudie quelques reactions d'hydrolyse, nous avons compare la valeur de pH de neutralisation du cation hydrate et celle de precipitation de l'hydroxyde. Dans la seconde partie nous avons aborde l'etuce des dosages de l'acidite d'une solution aqueuse. Apres avoir envisage assez rapidement la determination de l'acidite 'totale', nous traitons du probleme du titrage de l'acidite 'libre'. Nous avons porte notre attention sur certaines methodes: extrapolation du point equivalent, titrimetrie colorimetrique avec ou sans complexant, et enfin utilisation des resines echangeuses d'ions en milieu aqueux et solvant mixte.

Theoretical calculations of the thermodynamic stability of ionic substitutions in hydroxyapatite under an aqueous solution environment

International Nuclear Information System (INIS)

Matsunaga, Katsuyuki; Murata, Hidenobu; Shitara, Kazuki

2010-01-01

Defect formation energies in materials generally depend on chemical potentials determined by a chemical equilibrium condition. In particular, an aqueous solution environment is important for biomaterials such as hydroxyapatite studied here. Therefore, a methodology to obtain ionic chemical potentials under chemical equilibrium between solid and aqueous solution was introduced, and was applied to substitutional divalent cations formed via ion exchange with Ca 2+ in hydroxyapatite. The calculated ranking of the stability of substitutional cations in HAp was in good agreement with the experimentally observed trend. The present theoretical approach would be useful to explore the thermodynamic stability of defects in materials subjected to an aqueous solution environment.

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

Science.gov (United States)

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.

Relaxation of the silver/silver iodide electrode in aqueous solution

NARCIS (Netherlands)

Peverelli, K.J.

1979-01-01

The aim of this study is to detect and characterize relaxation processes on silver/silver iodide electrodes in aqueous electrolyte solution. The information obtained is to be used for an estimation of the consequences of similar processes on colloidal AgI

Radiation dechlorination of PCE in aqueous solutions under various conditions

International Nuclear Information System (INIS)

Mucka, V.; Lizalova, B.; Pospisil, M.; Silber, R.; Polakova, D.

2002-01-01

Complete text of publication follows. Radiation technology of water purification from chlorinated compounds seems to be one of the promising method (Getoff, 1996), analogously as it was shown (Mueka et al., 2000) with radiation degradation of polychlorinated biphenyls (PCBs). A systematic study of dechlorination of tetrachloroethylene (PCE) in aqueous solutions (initial concentrations ranging from 9.2 x 10 -6 to 2.5 x 10 -4 mol dm -3 ), initiated by γ-rays of 60 Co or by accelerated electrons (EB, 4.5 MeV) in presence of various modifiers (atmospheric oxygen, N 2 O-oxide, HCO 3 - - and NO 3 - - ions as well as various pH-values), was the aim of this paper. The studies showed that both actual concentration c of PCE and radiation yield G(Cl - ) decreased rapidly with increasing dose up to the dose of 2 kGy and the degree of dechlorination raised sharply in this dose-interval. The dechlorination was slightly promoted by atmospheric oxygen. Similarly, a promotion effect was detected in the case of the PCE-solutions saturated, prior to their irradiation, with the N 2 O-oxide. On the other hand, a presence of NO 3 - - or HCO 3 - -ions in irradiated samples led to an inhibiting effect. The inhibiting effect increased markedly with increasing concentration of both at above-mentioned ions up to the concentration of about 100 mg dm -3 . A pronounced inhibition of γ-radiation dechlorination of PCE was observed in alkaline aqueous solutions. The results obtained in this paper support the idea that the radiation dechlorination of PCE in aqueous solutions proceeds via an oxidative mechanism in which the γ-irradiation was found to be more effective than the EB-irradiation

The electrochemical corrosion of bulk nanocrystalline ingot iron in HCl solutions with different concentrations

International Nuclear Information System (INIS)

Wang, S.G.; Sun, M.; Cheng, P.C.; Long, K.

2011-01-01

Highlights: → The corrosion resistance of BNII was enhanced in comparison with CPII in 0.1-0.4 mol L -1 solution. → The function work of BNII is 0.47 eV larger that of CPII. → The energy state density of 4s electrons of BNII is 13.73% less than that of CPII. → BNII corrosion resistance was enhanced due to its larger work function and less 4s electrons weight. → The specific adsorption of Cl - on BNII was weaker than that of CPII due to its larger function work. - Abstract: We studied the corrosion properties of bulk nanocrystalline ingot iron (BNII) and conventional polycrystalline ingot iron (CPII) in HCl solutions from 0.1 mol L -1 to 0.4 mol L -1 at room temperature. The corrosion resistance of BNII was enhanced in comparison with CPII. We investigated the surface energy state densities of BNII and CPII with ultra-violet photoelectron spectroscopy. The energy state density of BNII 4s electrons was 13.73% less than that of CPII. The function work of BNII was 0.47 eV larger that of CPII. The corrosion resistance of BNII was enhanced in comparison with CPII due to its less energy state density of 4s electrons, larger work function and weaker Cl - specific adsorption.

Rates of Decomposition of N-Chloramine Disinfectant Compounds in Aqueous Solutions

International Nuclear Information System (INIS)

EI-Bellihi, E.E.

2009-01-01

The effect of temperature, ph, and salt effects on the decomposition kinetics of hydrolysis of N-chloramine disinfectant compounds [chloramine-B, chloramine-T, N-chlorosuccinimide (NCS), and 1,3-dichloro-5,5-dimethyl hydantoin (DCDMH or Halane)] in aqueous solutions was studied. The results should that the hydrolytic stability of CB and CT is greater than that of NCS and halane. Using CT, which is practical in use for its long contact times, reduced its initial concentration in aqueous solution from 100 ppm to about 20 ppm after a period of 6 months. The study also showed that the rate of hydrolysis of NCS is almost independent on the H + ions concentration. On the other hand, the rates of hydrolysis of CB and CT depend strongly on the hydrogen ion (H + ) concentration where the kinetic of the reaction changes from zero-order to a first order. The thermodynamic parameters of activation were calculated and showed that the entropies of activation have large negative values due to the increase in electrostriction and in a loss of freedom of the solvent water molecules associated with the separation of ions in the transition state. A linear compensation between ΔH and ΔS suggests that in the pure aqueous solutions, the reaction mechanism is almost the same for all the chloramine compounds under investigation

Removal of patulin from aqueous solutions by propylthiol functionalized SBA-15

Energy Technology Data Exchange (ETDEWEB)

Appell, Michael, E-mail: michael.appell@ars.usda.gov [Bacterial Foodborne Pathogens and Mycology Research Unit, United States Department of Agriculture, Agricultural Research Service, National Center for Agricultural Utilization Research, 1815 N. University St., Peoria, IL 61604 (United States); Jackson, Michael A.; Dombrink-Kurtzman, Mary Ann [Renewable Product Technology Research Unit, United States Department of Agriculture, Agricultural Research Service, National Center for Agricultural Utilization Research, 1815 N. University St., Peoria, IL 61604 (United States)

2011-03-15

Propylthiol functionalized SBA-15 silica was investigated to detoxify aqueous solutions contaminated with the regulated mycotoxin patulin. Micelle templated silicas with a specific pore size were synthetically modified to possess propylthiol groups, a functional group known to form Michael reaction products with the conjugated double bond system of patulin. BET surface area analysis indicated the propylthiol functionalized SBA-15 possesses channels with the pore size of 5.4 nm and a surface area of 345 m{sup 2} g{sup -1}. Elemental analysis indicates the silicon/sulfur ratio to be 10:1, inferring one propylthiol substituent for every ten silica residues. The propylthiol modified SBA-15 was effective at significantly reducing high levels of patulin from aqueous solutions (pH 7.0) in batch sorption assays at room temperature. The material was less effective at lower pH; however heating low pH solutions and apple juice to 60 deg, C in the presence of propylthiol functionalized SBA-15 significantly reduced the levels of patulin in contaminated samples. Composite molecular models developed by semi-empirical PM3 and empirical force field methods support patulin permeation through the mesoporous channels of propylthiol functionalized SBA-15. Density functional study at the B3LYP/6-31G(d,p) level predicts the proposed patulin adducts formed by reaction with the thiol residues exhibit less electrophilic properties than patulin. It is demonstrated the use of propylthiol functionalized SBA-15 is a viable approach to reduce patulin levels in aqueous solutions, including contaminated apple juice.

Removal of patulin from aqueous solutions by propylthiol functionalized SBA-15

International Nuclear Information System (INIS)

Appell, Michael; Jackson, Michael A.; Dombrink-Kurtzman, Mary Ann

2011-01-01

Propylthiol functionalized SBA-15 silica was investigated to detoxify aqueous solutions contaminated with the regulated mycotoxin patulin. Micelle templated silicas with a specific pore size were synthetically modified to possess propylthiol groups, a functional group known to form Michael reaction products with the conjugated double bond system of patulin. BET surface area analysis indicated the propylthiol functionalized SBA-15 possesses channels with the pore size of 5.4 nm and a surface area of 345 m 2 g -1 . Elemental analysis indicates the silicon/sulfur ratio to be 10:1, inferring one propylthiol substituent for every ten silica residues. The propylthiol modified SBA-15 was effective at significantly reducing high levels of patulin from aqueous solutions (pH 7.0) in batch sorption assays at room temperature. The material was less effective at lower pH; however heating low pH solutions and apple juice to 60 deg, C in the presence of propylthiol functionalized SBA-15 significantly reduced the levels of patulin in contaminated samples. Composite molecular models developed by semi-empirical PM3 and empirical force field methods support patulin permeation through the mesoporous channels of propylthiol functionalized SBA-15. Density functional study at the B3LYP/6-31G(d,p) level predicts the proposed patulin adducts formed by reaction with the thiol residues exhibit less electrophilic properties than patulin. It is demonstrated the use of propylthiol functionalized SBA-15 is a viable approach to reduce patulin levels in aqueous solutions, including contaminated apple juice.

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

International Nuclear Information System (INIS)

Wolery, T.J.

1992-01-01

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 desired 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 = -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

Enhanced catalytic performance of Pd catalyst for formic acid electrooxidation in ionic liquid aqueous solution

Science.gov (United States)

Feng, Yuan-Yuan; Yin, Qian-Ying; Lu, Guo-Ping; Yang, Hai-Fang; Zhu, Xiao; Kong, De-Sheng; You, Jin-Mao

2014-12-01

A protic ionic liquid (IL), n-butylammonium nitrate (N4NO3), is prepared and employed as the electrolyte for formic acid electrooxidation reaction (FAOR) on Pd catalysts. The oxidation peak potential of FAOR in the IL solution shows about a 200 mV negative shift as compared with those in traditional H2SO4/HClO4 electrolytes, suggesting that FAOR can be more easily carried out on Pd catalysts in IL media. The catalytic properties of Pd toward FAOR are not only dependent on the concentration of IL, as a consequence of the varied electronic conductivity of the IL solution, but also on the high potential limit of the cyclic voltammograms. When the Pd catalyst is cycled up to 1.0 V (vs. SCE), which induces a significant oxidation of Pd, it shows ca. 4.0 times higher activity than that not subjected to the Pd oxidation (up to 0.6 V). The Pd oxides, which are more easily formed in IL solution than in traditional H2SO4/HClO4 electrolytes, may play a crucial role in increasing the catalytic activities of Pd toward FAOR. Our work would shed new light on the mechanism of FAOR and highlight the potential applications of IL as green and environment-friendly electrolytes in fuel cells and other technologies.

Chemical metallization of KMPR photoresist polymer in aqueous solutions

Energy Technology Data Exchange (ETDEWEB)

Zeb, Gul [MiQro Innovation Collaborative Centre (C2MI), 45, boul. de l' Aéroport, Bromont, QC, J2L 1S8 (Canada); Mining & Materials Engineering, McGill University, 3610,University Street, Montreal, QC, H3A 0C5 (Canada); Duong, Xuan Truong [Department of Mechanical Engineering, Ecole polytechnique de Montréal, Montréal, QC, H3C 3T5 (Canada); Thai Nguyen University of Technology, 3-2 Street, Thai Nguyen City (Viet Nam); Vu, Ngoc Pi; Phan, Quang The; Nguyen, Duc Tuong; Ly, Viet Anh [Thai Nguyen University of Technology, 3-2 Street, Thai Nguyen City (Viet Nam); Salimy, Siamak [ePeer Review LLC, 145 Pine Haven Shores Rd, Suite 1000-X, Shelburne, VT 05482 (United States); Le, Xuan Tuan, E-mail: xuantuan.le@teledyne.com [MiQro Innovation Collaborative Centre (C2MI), 45, boul. de l' Aéroport, Bromont, QC, J2L 1S8 (Canada); Thai Nguyen University of Technology, 3-2 Street, Thai Nguyen City (Viet Nam)

2017-06-15

Highlights: • Electroless deposition of Ni-B film on KMPR photoresist polymer insulator with excellent adhesion has been achieved. • This metallization has been carried out in aqueous solutions at low temperature. • Polyamine palladium complexes grafts serve as seeds for the electroless plating on KMPR. • This electroless metallization process is simple, industrially feasible, chromium-free and environment-friendly. - Abstract: While conventional methods for preparing thin films of metals and metallic alloys on insulating substrates in the field of microelectromechanical systems (MEMS) include vapor deposition techniques, we demonstrate here that electroless deposition can be considered as an alternate efficient approach to metallize the surface of insulating substrates, such as KMPR epoxy photoresist polymer. In comparison with the physical and chemical vapor deposition methods, which are well-established for metallization of photoresist polymers, our electroless nickel plating requires only immersing the substrates into aqueous solutions in open air at low temperatures. Thin films of nickel alloy have been deposited electrolessly on KMPR surface, through a cost-effective and environmental chromium-free process, mediated through direct grafting of amine palladium complexes in aqueous medium. This covalent organic coating provides excellent adhesion between KMPR and the nickel film and allows better control of the palladium catalyst content. Covalent grafting and characterization of the deposited nickel film have been carried out by means of Fourier-transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy techniques.

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

Science.gov (United States)

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.

Chemical systems in aqueous solutions for using in the holographic ionizing radiation

International Nuclear Information System (INIS)

Nicolau-Rebigan, S.

1979-01-01

Some types of chemical systems in aqueous solutions for utilization as active media in holographic ionizing radiation dosimeter are presented. One discussed some advantages of the holographic dosimeter comparatively with another existing types. It is outlined the advantages of using aqueousss solutions as active media in holographic dosimeter. (author)

Removal of phosphate and nitrate from aqueous solution using ...

African Journals Online (AJOL)

sunny t

water, 3.5 g of NaCl were dissolved to obtain 3.5 g/l salinity final solution. When the ... The nitrate adsorption was highly pH dependent, which affects the ... adsorption mechanism that the optimum pH for phosphate removal by .... Biosorption of copper(ii) from aqueous ... Accumulation and detoxification of toxic elements by ...

Study of iodine-iodate isotopic exchange reaction in neutral aqueous solutions by radiotracer technique

International Nuclear Information System (INIS)

Tripathi, R.; Ram, K.D.

1993-01-01

The isotopic exchange of iodine atoms in neutral aqueous solutions of iodate ions and iodine (in KI) is found to obey the rate law R = k [IO 3 - ] 0.4 [I 2 ] 1.2 at 175 o C. The addition of neutral ionic salts, e.g. KCl and KNO 3 , in the reaction mixture showed a slight catalytic effect on the exchange rate. Further, the kinetic salt effect indicated the involvement of at least one neutral species on the rate-determining step. The activation energy in neutral aqueous solutions of iodate ions and iodine is found to be 86 ± 3 kJ mol -1 , which decreases in the presence of KCl (79 ± 3 kJ mol -1 and KNO 3 (82 + 3 kJ mol -1 ). The activation parameters, viz. free energy of activation, enthalpy of activation and entropy of activation, were also calculated. Based on these results, an association-dissociation type of reaction mechanism is proposed for this exchange reaction in neutral aqueous medium, similar to that proposed earlier for iodide-iodate isotopic exchange reaction in neutral aqueous solutions, nitrate eutectic melts and iodide-iodate melts. (author)

Sb{sup III} - Sb{sup V} Exchange Reaction in Hydrochloric: Acid Solutions; Echange Sb{sup III}-Sb{sup V} dans des Solutions d'Acide Chlorhydrique; Reaktsiya obmena Sb(III) - Sb(V) v rastvorakh khloristovodorodnoj kisloty; Intercambio Sb{sup III}-Sb{sup V} en Soluciones de HCl

Energy Technology Data Exchange (ETDEWEB)

Kambara, T.; Yamaguchi, K.; Yasuba, S. [Shizuoka University, Shizuoka City (Japan)

1965-10-15

The exchange reaction of Sb{sup III} - Sb{sup V} in solutions of low HCl concentrations was studied using {sup 124}Sb as a tracer. The effects of HCl concentrations and chemical forms of antimony on the exchange rate were investigated. The HCl concentrations of the antimony solutions ((Sb{sup III}) =(Sb{sup V}) = 6.8 x 10{sup -4}M) were changed from 0.8 to 4.0M and the half-time for the exchange was measured by plotting log (1 - F) versus time t to calculate the exchange rate assuming the second-ordet reaction. It was found that the exchange rate was sharply increased with the increase of HCl concentrations (at 25 Degree-Sign C, from 0.8 to 2.0M) and at 2.0M HCl concentration the rate reached the maximum, from which the rate was decreased with the increase of HCl concentrations (at 25 Degree-Sign C, from 2.0 to 4.0M). Two sorts of Sb{sup V} species were used for our investigations, i.e. one was used directly after the dilution of 10M HCl Sb{sup V} solution with water and the other was used after 24 hours standing at room temperature from the dilution. (The Sb{sup III} species were also kept standing after preparation from 10M HCl Sb{sup III} solution.) In both cases the maximum rates were found to exist at 2.0M HCl concentration. The rate R{sub 1} for the former (directly after dilution) was 4.5 x 10{sup -6} mole litre{sup -1} min{sup -1} and the rate R{sub 2} for the latter (24 hours standing) was 1.2 x 10{sup -}{sub 6} mole litre. Also the activation energy for these cases was found to be 12.2 kcal/mole and 19.1 kcal/mole. By spectrophotometric studies, the Sb{sup V} species of the former type were found to be mainly consisting of SbCl{sup -}{sub 6} and the species of the latter type to be of SbCl{sub 4}(OH){sup -}{sub 2}, etc. Besides these facts the form of Sb{sup III} species was found to have no influence on the exchange rate. A much sharper increase of the exchange rate was observed when the HCl concentration of the antimony solution was fixed at 0.8M and

Experiment and model for the surface tension of amine–ionic liquids aqueous solutions

International Nuclear Information System (INIS)

Zhang, Pan; Du, LeiXia; Fu, Dong

2014-01-01

Highlights: • The surface tensions of MEA/DEA–ionic liquids aqueous solutions were measured. • The experiments were modeled satisfactorily by using a thermodynamic equation. • The temperature dependence of the surface tension was illustrated. • The effects of the mass fractions of MEA/DEA and ionic liquids were demonstrated. - Abstract: The surface tension (γ) of 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF 4 ])–monoethanolamine (MEA), 1-butyl-3-methylimidazolium bromide ([Bmim][Br])–MEA, [Bmim][BF 4 ]–diethanolamine (DEA) and [Bmim][Br]–DEA aqueous solutions was measured by using the BZY-1 surface tension meter. The temperature ranged from (293.2 to 323.2) K. The mass fraction of amines and ionic liquids (ILS) respectively ranged from 0.15 to 0.30 and 0.05 to 0.10. A thermodynamic equation was proposed to model the surface tension of amines–ILS aqueous solutions and the calculated results agreed well with the experiments. The effects of temperature, mass fraction of amines and ILS on the surface tension were demonstrated on the basis of experiments and calculations

Four-photon Rayleigh-wing spectroscopy of the aqueous solution of α-chymotrypsin protein

International Nuclear Information System (INIS)

Bunkin, Aleksei F; Nurmatov, Alisher A; Pershin, Sergei M; Lebedenko, S I

2006-01-01

The spectra of coherent librations of H 2 O molecules, coinciding in frequencies with the rotational spectrum of gaseous H 2 O, are observed for the first time in aqueous solutions of α-chymotrypsin protein and hydrogen peroxide and in deionised Milli-Q water by the method of four-photon laser scattering in the frequency range 0-100 cm -1 . The resonance contribution of molecular librations to the four-photon scattering signal considerably increases in aqueous solutions compared to water. The resonances related to the lines of the ortho- and para-modifications of the natural isotope of the H 2 O molecule in the gas phase are recorded in the four-photon scattering spectra. It is found that the protein molecule in aqueous solution selectively interacts with the para-H 2 O, which makes it possible to interpret some features of the interaction of microwave radiation with biological objects and to develop a new class of laser biotechnologies. (special issue devoted to the 90th anniversary of a.m. prokhorov)

Degradation of di-2-ethylhexyl phthalate in aqueous solution by advanced oxidation process

Directory of Open Access Journals (Sweden)

Maryam Zarean

2015-01-01

Conclusion: It could be found that the UV/O3 process is a method for DEHP degradation in aqueous solution and may be recommended as a supplement with other processes for treatment of solutions containing low DEHP concentrations.

Process for disposal of aqueous solutions containing radioactive isotopes

Science.gov (United States)

Colombo, Peter; Neilson, Jr., Robert M.; Becker, Walter W.

1979-01-01

A process for disposing of radioactive aqueous waste solutions whereby the waste solution is utilized as the water of hydration to hydrate densified powdered portland cement in a leakproof container; said waste solution being dispersed without mechanical inter-mixing in situ in said bulk cement, thereafter the hydrated cement body is impregnated with a mixture of a monomer and polymerization catalyst to form polymer throughout the cement body. The entire process being carried out while maintaining the temperature of the components during the process at a temperature below 99.degree. C. The container containing the solid polymer-impregnated body is thereafter stored at a radioactive waste storage dump such as an underground storage dump.

Process for disposal of aqueous solutions containing radioactive isotopes

International Nuclear Information System (INIS)

Colombo, P.; Neilson, R.M. Jr.; Becker, W.W.

1979-01-01

A process for disposing of radioactive aqueous waste solutions whereby the waste solution is utilized as the water of hydration to hydrate densified powdered portland cement in a leakproof container; said waste solution being dispersed without mechanical inter-mixing in situ in said bulk cement, thereafter the hydrated cement body is impregnated with a mixture of a monomer and polymerization catalyst to form polymer throughout the cement body. The entire process being carried out while maintaining the temperature of the components during the process at a temperature below 99 0 C. The container containing the solid polymer-impregnated body is thereafter stored at a radioactive waste storage dump such as an underground storage dump

Apparent molal volumes of HMT and TATD in aqueous solutions around the temperature of maximum density of water

International Nuclear Information System (INIS)

Clavijo Penagos, J.A.; Blanco, L.H.

2012-01-01

Highlights: ►V φ for HMT and TATD in aqueous solutions around the temperature of maximum density of water are reported. ► V φ is linear in m form m = 0.025 for all the aqueous solutions investigated. ► Variation of V ¯ 2 ∞ with T obeys a second grade polynomial trend. ► The solutes are classified as structure breakers according to Hepler’s criterion. - Abstract: Apparent molal volumes V φ have been determined from density measurements for several aqueous solutions of 1,3,5,7-tetraazatricyclo[3.3.1.1(3,7)]decane (HMT) and 1,3,6,8-tetraazatricyclo[4.4.1.1(3,8)]dodecane (TATD) at T = (275.15, 275.65, 276.15, 276.65, 277.15, 277.65 and 278.15) K as function of composition. The infinite dilution partial molar volumes of solutes in aqueous solution are evaluated through extrapolation. Interactions of the solutes with water are discussed in terms of the effect of the temperature on the volumetric properties and the structure of the solutes. The results are interpreted in terms of water structure-breaking or structure forming character of the solutes.

Radiolytic effect on the chemical state of iodine in aqueous solution

International Nuclear Information System (INIS)

Shiraishi, H.; Kimiya, T.; Ohmae, M.; Ishigure, K.

1988-01-01

The oxidation state of iodine dissolved in an aqueous solution is easily changed in the presence of radiation field. Hence, it is essential to take the radiolytic effect into account when one is to estimate chemical forms of iodine after being released into the containment under an LOCA condition. This paper summarizes results of γ-radiolysis experiments on aqueous solutions containing iodine species, which have been carried out to extend the previously reported study on the same system. Variation in iodine product distribution with time has been examined as before, utilizing a flow system under irradiation. Attention has been paid to the effect of oxygen, to that of an initial oxidation state of iodine, and to the influence of temperature. Some kinetic analysis on the system was also undertaken

Gamma radiolysis of alkaline aqueous solutions of neptunium and plutonium ions

International Nuclear Information System (INIS)

Pikaev, A.K.; Gogolev, A.V.; Shilov, V.P.

1998-01-01

Full text: The paper is a brief review of data obtained by the authors from the study on redox reactions of neptunium and plutonium ions upon γ radiolysis of their aerated alkaline aqueous solutions. It includes the information on radiolytic reduction of Np(V), Np(VI) and Pu(VI) ions under various experimental conditions. It was found that the values of Np(VI) and Pu(VI) reduction yields do not depend on alkali concentration. The values considerably increase in the presence of some organic compounds (EDTA and formate were investigated). The formation of the Np(V) peroxo complex was observed in the γ radiolysis of alkaline aqueous solutions of Np(VI) and Np(V) in the presence of nitrate. The mechanism of radiolytic redox reactions of the ions is discussed in some detail

Oligonucleotides as probes for studying polymerization reactions in dilute aqueous solution

Science.gov (United States)

Kolb, V.; Orgel, L. E.; Miller, S. L. (Principal Investigator)

1994-01-01

We have prepared a [32P]-labled oligonucleotide probe carrying a free primary amine at its 3'-terminus. This probe is used to initiate polymerization of aziridine (ethyleneimine) in aqueous solution. The nature of the oligomeric products and the kinetics of their formation are then monitored by gel electrophoresis. Our results are generally consistent with those obtained using conventional techniques. We have also investigated the effect of polyanionic templates on the rate of oligomerization of aziridine. We find that water-soluble polyanions generally accelerate the polymerization. The sodium salt of polymethacrylic acid is the most effective of the templates that we studied. The methods introduced in this paper should be applicable to a variety of polymerization reactions in aqueous solution. They should greatly simplify the screening of potentially prebiotic polymerization reactions.

Adsorption of nicotine on different zeolite types, from aqueous solutions

Directory of Open Access Journals (Sweden)

Stošić Dušan K.

2007-01-01

Full Text Available The plant alkaloid, nicotine, is a strongly toxic heterocyclic compound: the lethal dose for an adult human being (40-60 mg is importantly lower in comparison with the other known poisons such as arsenic or strychni­ne. Cigarettes represent "the most toxic and addictive form of nicotine". Besides the negative effects of nicotine on public health produced by self-administration, recently another potentially very dangerous effect has been recognized: because of its miscibility with water, nicotine can be found in industrial wastewaters, and consequently, in groundwater. Therefore, the problem of nicotine removal from aqueous solutions has became an interesting topic. In this work, the removal of nicotine has been probed by adsorption on solid materials. Adsorption of nicotine on different zeolites (clinoptilolite, ZSM-5 and β zeolite and on activated carbon was investigated from aqueous solutions, at 298 K. The obtained results are presented as adsorption isotherms: the amount of adsorbed nicotine as a function of equilibrium concentration. These data were obtained from the residual amount of nicotine in the aqueous phase, by the use of UV spectroscopy. The highest amounts of adsorbed nicotine was found for activated carbon and p zeolite (~ mmol·g-1. The attempt to modify the adsorption properties of ZSM-5 zeolite has been also done: ZSM-5 was modified by ion-exchange with VIII group metal (Cu2+ and Fe3+. In addition, the adsorption of nicotine on ZSM-5 zeolite with different Si/Al ratios has been done. It has been noticed that ion-exchange did not improve the adsorption possibilities, while the adsorption was importantly lower in the case of higher silicon content in ZMS-5 structure. 13C NMR spectra were collected for suspensions formed of solid adsorbent and aqueous solution of nicotine; in this way, the part of nicotine molecule which is most probably connected with the adsorbent was recognized.

Enthalpic characteristics of interactions occurring between an ascorbic acid and some saccharides in aqueous solutions

International Nuclear Information System (INIS)

Terekhova, Irina V.; Kulikov, Oleg V.; Titova, Elena S.

2004-01-01

The enthalpies of solution of mono- and disaccharides were measured in water and aqueous ascorbic acid solutions at 298.15 K using a calorimeter of solution. Enthalpies of transfer of saccharides from water to aqueous ascorbic acid solutions were derived, and enthalpic coefficients of pair interaction h xy were calculated according to MacMillan-Mayer theory. Interactions of ascorbic acid with D-fructose and sucrose are energetically favorable and characterized by negative h xy coefficients while h xy for the interactions occurring between ascorbic acid and α-D glucose, D-galactose and maltose are positive. The obtained results are interpreted in terms of the influence of structure and solvation of solutes on the thermodynamic parameters of their interaction in solutions

Investigation on Minimum Film Boiling Point of Highly Heated Vertical Metal Rod in Aqueous Surfactant Solution

Energy Technology Data Exchange (ETDEWEB)

Lee, Chi Young; Kim, Jae Han [Pukyong Nat’l Univ., Busan (Korea, Republic of)

2017-09-15

In this study, experiments were conducted on the MFB(minimum film boiling) point of highly heated vertical metal rod quenched in aqueous surfactant solution at various temperature conditions. The aqueous Triton X-100 solution(100 wppm) and pure water were used as the liquid pool. Their temperatures ranged from 77 °C to 100 °C. A stainless steel vertical rod of initial center temperature of 500 °C was used as a test specimen. In both liquid pools, as the liquid temperature decreased, the time to reach the MFB point decreased with a parallel increase in the temperature and heat flux of the MFB point. However, over the whole present temperature range, in the aqueous Triton X-100 solution, the time to reach the MFB point was longer, while the temperature and heat flux of the MFB point were reduced when compared with pure water. Based on the present experimental data, this study proposed the empirical correlations to predict the MFB temperature of a high temperature vertical metal rod in pure water and in aqueous Triton X-100 solution.

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

Science.gov (United States)

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.

Rapid structural analysis of nanomaterials in aqueous solutions

Science.gov (United States)

Ryuzaki, Sou; Tsutsui, Makusu; He, Yuhui; Yokota, Kazumichi; Arima, Akihide; Morikawa, Takanori; Taniguchi, Masateru; Kawai, Tomoji

2017-04-01

Rapid structural analysis of nanoscale matter in a liquid environment represents innovative technologies that reveal the identities and functions of biologically important molecules. However, there is currently no method with high spatio-temporal resolution that can scan individual particles in solutions to gain structural information. Here we report the development of a nanopore platform realizing quantitative structural analysis for suspended nanomaterials in solutions with a high z-axis and xy-plane spatial resolution of 35.8 ± 1.1 and 12 nm, respectively. We used a low thickness-to-diameter aspect ratio pore architecture for achieving cross sectional areas of analyte (i.e. tomograms). Combining this with multiphysics simulation methods to translate ionic current data into tomograms, we demonstrated rapid structural analysis of single polystyrene (Pst) beads and single dumbbell-like Pst beads in aqueous solutions.

Pulse Radiolysis of Adrenaline in Acid Aqueous Solutions

DEFF Research Database (Denmark)

Gohn, M.; Getoff, N.; Bjergbakke, Erling

1976-01-01

Pulse radiolysis of adrenaline in acid aqueous solutions (pH 1–3) was carried out. The rate constants for the reactions of adrenaline with H and OH were determined: k(H + adr.) = (0·9±0·1) × 109 dm3 mol−1s−1; k(OH + adr.) = (1·65±0·15) × 1010 dm3 mol−1s−1. The H-adduct of adrenaline has two λmax...

Tyrosine-sensitized photodimerization of thymine in aqueous solution

International Nuclear Information System (INIS)

Kaneko, M.; Matsuyama, A.; Nagata, C.

1978-01-01

Photodimerization of thymine in aqueous solution in the presence of tyrosine was studied with monochromatic UV irradiation. The total dimer formation was sensitized in the presence of tyrosine. The action spectrum of sensitized total dimer formation has a peak near 280 nm corresponding to the absorption maximum of tyrosine. Triplet quenchers reduced the sensitization substantially. It seems probable that tyrosine-sensitized photodimerization of thymine occurred via triplet-triplet energy transfer from tyrosine to thymine. (author)

The biosorption of cadmium and lead ions from aqueous Solution ...

African Journals Online (AJOL)

The biosorption potentiality of Musa paradisiaca stalk at removing cadmium and lead ions from aqueous solution was investigated. The biosorption experiment was carried out as a function of contact time, initial pH, initial metal ion concentration and biosorbent dose. Adsorption equilibria were obtained from batch ...

Heterogeneous primary nucleation of ice in water and aqueous solutions

NARCIS (Netherlands)

Thijssen, H.A.C.; Vorstman, M.A.G.; Roels, J.A.

1968-01-01

The effect of the volume of the liquid sample, the degree of turbulence in the liquid, and the rate of cooling upon the probability of nucleation has been studied for water and aqueous solutions. Nucleation rates were measured for droplets nearly instantaneously cooled to a predetermined

Efficient device for the benign removal of organic pollutants from aqueous solutions using modified mesoporous magnetite nanostructures

Science.gov (United States)

Vojoudi, H.; Badiei, A.; Amiri, A.; Banaei, A.; Ziarani, G. M.; Schenk-Joß, K.

2018-02-01

In this study, a home-made device comprising a column filled with magnetic mesoporous silica-coated nanostructures (MSCM-PA) as an adsorbent was constructed and used to remove organic pollutants from aqueous solutions. The MSCM-PA adsorbent was prepared and characterized using Fourier transform-infrared spectroscopy, ultraviolet-visible spectroscopy, scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, vibrating sample magnetometry, Brunauer-Emmett-Teller, thermogravimetric analysis/differential thermal analysis, and powder X-ray diffraction techniques. The adsorption behavior of the MSCM-PA sorbent was studied based on the removal of Everzol blue dye from aqueous solutions. We investigated the effects of various parameters such as the solution pH, initial dye concentration, adsorbent dose, flow rate, and contact time on the adsorption of Everzol blue from aqueous solutions. The adsorption data were modeled using Langmuir and Freundlich isotherms, and a good fit was obtained with the Langmuir isotherm. The maximum Everzol blue adsorption capacity by MSCM-PA was 162 mg g-1. The results indicate that our device is capable of adsorbing anionic dyes from aqueous solutions.

Chemical dosimetry by UV spectrophotometry of aqueous ascorbic acid solutions

International Nuclear Information System (INIS)

Alian, A.; El-Assay, N.B.; Abdel-Rehim, F.; Amin, N.E.; McLaughlin, W.L.; Roushdy, H.

1984-01-01

The decrease in the ultraviolet absorption of aqueous solutions of ascorbic acid brought about by large doses of gamma radiation has been investigated as a means of developing a new chemical dosimeter. Because of spontaneous ring opening under various conditions after dissolution in water, some additives were examined as possible stabilizers against such denaturing of aqueous ascorbic acid. At an ascorbic acid concentration of 10 -4 M, either 1 to 2% glycine or 0.2 M NaCl was found to be a good stabilizer. A mechanism of radiation chemistry has been proposed based on hydroxyl radical and hydroxyl adduct intermediates, leading to dehydroascorbic acid through the ascorbate complex. The optimum dosimeter solution covers an absorbed dose range approx. 50 to 350 Gy, when measured at 264 nm wavelength. The G-values for dehydroascorbic acid production were determined to be 2.94 +- 0.33 and 2.43 +- 0.11 (100 eV) -1 , with glycine and NaCl used respectively as stabilizers. (author)

Effect of solvent composition on the limiting current of anodic dissolution of tungsten in aqueous-ethanol solutions of alkali

International Nuclear Information System (INIS)

Konoplyantseva, N.A.; L'vova, L.A.; Davydov, A.D.; AN SSSR, Moscow. Inst. Ehlektrokhimii)

1987-01-01

The effect of quantitative composition of solvent on tungsten anodic dissolution in aqueous-ethanol solutions of KOH is studied. It is shown that with an increase in ethanol content in aqueous-ethanol solutions of alkali the limiting current of tungsten anodic dissolution decreases. An increase in KOH concentration in certain limits (in ethanol solutions it is the range between 0.75 and 1.0 M KOH) results in the increase of the limiting current; with further increase in solution concentration the limiting current decreases, which can be related to the change of the limiting stage. An assumption is made that total reaction of tungsten anodic dissolution and the main reasons for the limiting current appearance do not change from aqueous to aqueous-ethanol and ethanol solutions of alkali

Correlation and prediction of osmotic coefficient and water activity of aqueous electrolyte solutions by a two-ionic parameter model

International Nuclear Information System (INIS)

Pazuki, G.R.

2005-01-01

In this study, osmotic coefficients and water activities in aqueous solutions have been modeled using a new approach based on the Pitzer model. This model contains two physically significant ionic parameters regarding ionic solvation and the closest distance of approach between ions in a solution. The proposed model was evaluated by estimating the osmotic coefficients of nine electrolytes in aqueous solutions. The obtained results showed that the model is suitable for predicting the osmotic coefficients in aqueous electrolyte solutions. Using adjustable parameters, which have been calculated from regression between the experimental osmotic coefficient and the results of this model, the water activity coefficients of aqueous solutions were calculated. The average absolute relative deviations of the osmotic coefficients between the experimental data and the calculated results were in agreement

Lactose and sucrose aqueous solutions for high-dose dosimetry with 10-MeV electron beam irradiation

International Nuclear Information System (INIS)

Amraei, R.; Kheirkhah, M.; Raisali, G.

2012-01-01

In the present study, dosimetric characterisation of aqueous solutions of lactose and sucrose was analysed by UV spectrometry following irradiation using 10-MeV electron beam at doses between 0.5 and 10.5 kGy. As a dosimetric index, absorbance is selected at 256 and 264 nm for lactose and sucrose aqueous solutions, respectively. The intensity of absorbance for irradiated solutions depends on the pre-irradiation concentration of lactose and sucrose. The post-irradiation stability of both solutions was investigated at room temperature for a measurement period of 22 d. (authors)

Immobilization of lead and cadmium from aqueous solution and contaminated sediment using nano-hydroxyapatite

International Nuclear Information System (INIS)

Zhang Zizhong; Li Mengyan; Chen Wei; Zhu Shuzhen; Liu Nannan; Zhu Lingyan

2010-01-01

The effectiveness and mechanism of nano-hydroxyapatite particles (nHAp) in immobilizing Pb and Cd from aqueous solutions and contaminated sediment were investigated. The maximum sorption amount (Q max ) of Pb and Cd in aqueous solution was 1.17 and 0.57 mmol/g. The X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) surface and depth analysis indicated that dissolution-precipitation is the primary immobilization mechanism for Pb, while surface complexation and intraparticle diffusion account for Cd sequestration. Different amounts of nHAp (0-10% nHAp/dry weight) were added to the contaminated sediment. Sequential extraction showed that nHAp could effectively reduce the exchangeable fraction of Pb and Cd in the sediment and significantly reduce the concentration in porewater. The results in this study showed that nHAp can immobilize Pb and Cd in sediment effectively. - Nano-hydroxyapatite shows potential and advantages to immobilize lead and cadmium in aqueous solution and sediment.

The importance of binder moisture content in Metformin HCL high-dose formulations prepared by moist aqueous granulation (MAG

Directory of Open Access Journals (Sweden)

Hiroshi Takasaki

2015-01-01

Full Text Available The aim of this study was to evaluate binders to improve the flowability of granulates and compactibility of Metformin HCL (Met using the moist aqueous granulation (MAG process. The effect of the binder moisture content on granulate and tablet quality was also evaluated. Vinylpyrrolidone–vinyl acetate copolymer (Kollidon VA64 fine: VA64, polyvidone (Povidone K12: PVP, hydroxypropyl cellulose (HPC SSL SF: HPC and hydroxypropyl methylcellulose (Methocel E5 LV: HPMC were evaluated as binders. These granulates, except for HPMC, had a lower yield pressure than Met active pharmaceutical ingredient (API. HPMC Met was not sufficiently granulated with low water volume. No problems were observed with the VA64 Met granulates during the tableting process. However, HPC Met granulates had a bowl-forming tendency, and PVP Met granulates had the tendency to stick during the tableting process. These bowl-forming and sticking tendencies may have been due to the low moisture absorbency of HPC and the high volume of bound water of PVP, respectively. VA64 Met granulates had the highest ambient moisture content (bulk water, bound water and moisture absorbency. It was concluded that the type of binder used for the Met MAG process has an impact on granulate flow and compactibility, as well as moisture absorbency and maintenance of moisture balance.

Alkaloids extract of Retama monosperma (L.) Boiss. seeds used as novel eco-friendly inhibitor for carbon steel corrosion in 1 M HCl solution: Electrochemical and surface studies

Energy Technology Data Exchange (ETDEWEB)

El Hamdani, Naoual; Fdil, Rabiaa [Laboratoire de Chimie Bioorganique, Faculté des Sciences, Université Chouaib Doukkali, B.P. 20, M-24000 El Jadida (Morocco); Tourabi, Mustapha [Laboratoire de Catalyse et de Corrosion des Matériaux (LCCM), Faculté des Sciences, Université Chouaib Doukkali, B.P. 20, M-24000 El Jadida (Morocco); Jama, Charafeddine [UMET-PSI, CNRS UMR 8207, ENSCL, Université Lille 1, CS 90108, F-59652 Villeneuve d’Ascq Cedex (France); Bentiss, Fouad, E-mail: fbentiss@enscl.fr [Laboratoire de Catalyse et de Corrosion des Matériaux (LCCM), Faculté des Sciences, Université Chouaib Doukkali, B.P. 20, M-24000 El Jadida (Morocco); UMET-PSI, CNRS UMR 8207, ENSCL, Université Lille 1, CS 90108, F-59652 Villeneuve d’Ascq Cedex (France)

2015-12-01

Graphical abstract: - Highlights: • AERS is good eco-friendly corrosion inhibitor for carbon steel in 1 M HCl. • AERS acts as mixed-type inhibitor in 1 M HCl medium. • AERS adsorption is well described by Langmuir isotherm. • Surface analyses were used to explain the AERS mechanism of carbon steel corrosion inhibition. - Abstract: Current research efforts now focus on the development of non-toxic, inexpensive and environmentally friendly corrosion inhibitors as alternatives to different organic and non-organic compounds. In this field, alkaloids extract of Retama monosperma (L.) Boiss. seeds (AERS) was tested for the first time as corrosion inhibitor for carbon steel in 1 M HCl medium using electrochemical and surface characterization techniques. The obtained results showed that this plant extract's acts as an efficient corrosion inhibitor for carbon steel in 1 M HCl and an inhibition efficiency of 94.4% was reached with 400 mg/L of AERS at 30 °C. Ac impedance experimental data revealed a frequency distribution of the capacitance, simulated as constant phase element. Impedance results demonstrated that the addition of the AERS in the corrosive solution decreases the charge capacitance and simultaneously increases the function of the charge/discharge of the interface, facilitating the formation of an adsorbed layer over the steel surface. Polarization curves indicated that AERS is a mixed inhibitor. Adsorption of such alkaloid extract on the steel surface obeyed to the Langmuir adsorption isotherm. X-ray photoelectron spectroscopy (XPS) showed that the inhibition of steel corrosion in normal hydrochloric solution by AERS is mainly controlled by a physisorption process and the inhibitive layer is composed of an iron oxide/hydroxide mixture where AERS molecules are incorporated.

Two components of Na emission in sonoluminescence spectrum from surfactant aqueous solutions.

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Hayashi, Yuichi; Choi, Pak-Kon

2015-03-01

Sonoluminescence from sodium dodecyl sulfate (SDS) aqueous solutions exhibits Na emission. The spectrum of Na emission was measured as a function of sonication time for a total of 30 min at an ultrasonic frequency of 148 kHz. The spectral line profiles changed with the sonication time, suggesting that the Na emission consists of two components: broadened lines, which are shifted from the original D lines, and unshifted narrow lines. The intensity of the unshifted narrow lines decreased at a greater rate than that of the broadened lines with increasing sonication time. This effect was enhanced at a higher acoustic power. The shifted broadened lines remained after sonication for 30 min. We propose that these quenching effects are caused by the accumulation of gases decomposed from SDS molecules inside bubbles. The CO₂ gas dependence of Na emission in NaCl aqueous solutions showed a similar change in the line profiles to that in SDS aqueous solutions, which supported this proposition. The unshifted narrow lines are easily affected by foreign gases. The results suggest that the two components originate from different environments around the emitting species, although both of them originate from the gas phase inside bubbles. The generation mechanisms of the two components are discussed. Copyright © 2014 Elsevier B.V. All rights reserved.

Removal of trace Cd2+ from aqueous solution by foam fractionation.

Science.gov (United States)

Lu, Jian; Li, Ying; Zhang, Sen; Sun, Yange

2015-04-09

In recent years, aqueous foam was known as an efficient technique with high potential on being used to remove heavy metal ions from the polluted water, not only because of the low cost, simple operation, but also ascribed to the high removal efficiency of trace heavy metal ions and would not cause secondary pollution to the environment. In this paper, the removal of Cd(2+) from aqueous solution by aqueous foam stabilized by a kind of novel anionic-nonionic surfactant sodium trideceth-4 carboxylate (AEC) was investigated. The effect of conditions such as surfactant/metal ions molar ratio, surfactant concentration on the removal efficiency was studied. In large concentration range of surfactant, the removal rate was higher than 90%, and could reach up to 99.8% under the optimum conditions. The Zeta potential of gas bubbles in the AEC solutions was determined to verify the combination between the negative charged group heads of surfactant molecules and heavy metal ions, and isothermal titration calorimeter (ITC) determination was utilized to demonstrate the interaction, which helped to understand the mechanisms more clearly. Copyright © 2015 Elsevier B.V. All rights reserved.

Bioremediation of zirconium from aqueous solution by coriolus versicolor: process optimization

International Nuclear Information System (INIS)

Amin, M.; Bhatti, H. N.; Sadaf, S.

2013-01-01

In the present study the potential of live mycelia of Coriolus versicolor was explored for the removal of zirconium from simulated aqueous solution. Optimum experimental parameters for the bioremediation of zirconium using C. versicolor biomass have been investigated by studying the effect of mycelia dose, concentration of zirconium, contact time and temperature. The isothermal studies indicated that the ongoing bioremediation process was exothermic in nature and obeyed Langmuir adsorption isotherm model. The Gibbs free energy (ΔG), entropy (ΔS) and enthalpy (ΔH) of bioremediation were also determined. The result showed that bioremediation of zirconium by live C. versicolor was feasible and spontaneous at room temperature. The equilibrium data verified the involvement of chemisorption during the bioremediation. The kinetic data indicated the operation of pseudo-second order process during the biosorption of zirconium from aqueous solution. Maximum bioremediation capacity (110.75 mg/g) of C. versicolor was observed under optimum operational conditions: pH 4.5, biomass dose 0.05 mg/100 mL, contact time 6 h and temperature 30 degree C. The results showed that C. versicolor could be used for bioremediation of heavy metal ions from aqueous systems. (author)

Adsorption of methylene blue from aqueous solution on the surface ...

African Journals Online (AJOL)

Adsorption of dye methylene blue from aqueous solution on the surface of sheep wool and cotton fibers was accomplished under the optimize conditions of temperature, concentration, pH, stay time duration and quantity of adsorbent. Spectrometric technique was used for the measurements of concentration of dye before ...

Solvation consequences of polymer PVP with biological buffers MES, MOPS, and MOPSO in aqueous solutions

International Nuclear Information System (INIS)

Gupta, Bhupender S.; Chen, Bo-Ren; Lee, Ming-Jer

2015-01-01

Highlights: • Densities and viscosities data for aqueous solutions with PVP and/or buffer. • The studied buffers include MES, MOPS, and MOPSO. • DFT was used to estimate the binding energies of the (PVP + buffer) complexes. • The viscosity data were correlated with the Jones–Dole equation. • The investigated buffers behave as Kosmotropies. - Abstract: Densities and viscosities were measured for the aqueous buffer (MES, MOPS, or MOPSO) solutions containing different concentrations of polyvinylpyrrolidone (PVP) (5, 10, 15, 20 and 30) mass% at temperatures from (298.15 to 318.15) K under atmospheric pressure. The DFT calculations were also performed and the binding energies of the possible (PVP + buffer) complexes were obtained. The experimental and computational results reveal the interactions of the PVP with the constituent compounds in the aqueous buffer solutions. Additionally we have explored the solvation behavior of the buffers by measuring the densities and the viscosities data of the aqueous buffer solutions from (0.0 to 1.0) mol · kg"−"1 at temperatures from (298.15 to 318.15) K. The viscosity results were correlated with the Jones–Dole equation. The correlated results confirmed that all the investigated buffers behave as Kosmotropes (structure makers).

Electrochemical oxidation of zirconium alloys in pre-transition and post-transition kinetic regimes at corrosion in electrolyte solutions

International Nuclear Information System (INIS)

Barkov, A.A.; Shavshin, V.M.

1986-01-01

With the aim of investigation on oxidation of zirconium alloys (Zr+2.5% Nb) the critical thickness of beginning of spalling of froming oxide films in HCl and NHO 3 aqueous solutions was evaluated by coulometry with accelerated procedure. Some variants of predeposition of modificated oxide coatings are proposed increase pre-transition regime time and to decrease corrosion during post-transition regime. Increase in agressivity of solutions (addition of 1 vol.% HF) and UV irradiation are found to increase 3-4 times pre-transition period

NMR studies of proton exchange kinetics in aqueous formaldehyde solutions.

Science.gov (United States)

Rivlin, Michal; Eliav, Uzi; Navon, Gil

2014-05-01

Aqueous solutions of formaldehyde, formalin, are commonly used for tissue fixation and preservation. Treatment with formalin is known to shorten the tissue transverse relaxation time T2. Part of this shortening is due to the effect of formalin on the water T2. In the present work we show that the shortening of water T2 is a result of proton exchange between water and the major constituent of aqueous solutions of formaldehyde, methylene glycol. We report the observation of the signal of the hydroxyl protons of methylene glycol at 2ppm to high frequency of the water signal that can be seen at low temperatures and at pH range of 6.0±1.5 and, at conditions where it cannot be observed by the single pulse experiment, it can be detected indirectly through the water signal by the chemical exchange saturation transfer (CEST) experiment. The above finding made it possible to obtain the exchange rate between the hydroxyl protons of the methylene glycol and water in aqueous formaldehyde solutions, either using the dispersion of the spin-lattice relaxation rate in the rotating frame (1/T1ρ) or, at the slow exchange regime, from the line width hydroxyl protons of methylene glycol. The exchange rate was ∼10(4)s(-1) at pH 7.4 and 37°C, the activation energy, 50.2kJ/mol and its pH dependence at 1.1°C was fitted to: k (s(-1))=520+6.5×10(7)[H(+)]+3.0×10(9)[OH(-)]. Copyright © 2014. Published by Elsevier Inc.

The radiation-induced degradation of a diazo dye in aqueous solution Pt. 2

International Nuclear Information System (INIS)

El-Assy, N.B.; Abdel-Rehim, F.; Abdel-Gawad, A.S.; Abdel-Fattah, A.A.

1992-01-01

The effect of γ-radiation on the color intensity of aerated, deaerated and oxygenated aqueous solutions of a diazo dye (Helion Red 8B) has been investigated. The decoloration yields of Helion Red 8B neutral aqueous solution, G(-Dye), for the nitrogen-, oxygen- and aerated-saturated solutions were found to be 0.77, 0.46 and 0.36 in the respective early stage. The rate constant for the reaction of the OH radical with the HR8B dye, obtained from competition kinetics using ethanol, was found to be 1.3*10 10 M -1 *s -1 . In aerated solutions (pH 3), the G(-Dye) decreased markedly upon the addition of a very small amount of ethanol. Suggestions are made for possible use of the dye as a radiation dosimeter in the dose range of 0.1 to 2 kGy. (author) 16 refs.; 8 figs.; 1 tab

Investigation of the removal of chromium (VI by Nanocomposites Chitosan-tragacanth solution from aqueous solution

Directory of Open Access Journals (Sweden)

Adel Almasi Nahnaji

2016-03-01

Full Text Available Background: The aim of this study was to investigate the removal of chromium (VI by Nanocomposites Chitosan-tragacanth solution from aqueous solution. Methods: In this study, chitosan-tragacanth nanocomposites were synthesized and analyzed by electron microscopy (SEM, (TEM and Fourier transform spectroscopy (FT-IR for the size and shape of the surface. The nano-composite of chitosan-tragacanth, for the adsorption of chromium (VI in aqueous solution was used as adsorbent. Results: The optimum conditions with multiple experiments to enhance the absorption were evaluated. The highest absorption of Cr (VI was occurred in the adsorbent dosage of 0.2 g, 8 ppm concentration of chromium ions, the pH=6 and also retention time of 50 min; in 298 ˚K temperature. After determining optimal conditions of adsorption, isotherms equations and study and thermodynamic parameters were applied. Adsorption process of chromium (VI on nano-composite chitosan - Tragacanth was conformed with Temkin isotherm. Conclusion: The thermodynamic parameters such as standard Gibbs free energy changes, changes in enthalpy and entropy changes in the standard showed that the adsorption process of Cr (VI is spontaneous and heating, and kinetics studies of models Lagergren, Ho , Alovich and intraparticle is used, the results show that the adsorption kinetics follows the pseudo-second order.

Electrical Conductivity of Gamma Irradiated Aqueous Urea Solution and its Application for Determination of Absorbed Radiation Dose; Sife-Eldeen Dosimeter

International Nuclear Information System (INIS)

Sife- Eldeen, Kh.A.

2008-01-01

In This Study, the radiation induced electrical conductivity (RIC) of aqueous urea solutions was investigated after gamma radiolysis. It was found that the RIC depends on preirradiation urea concentration, absorbed radiation dose and storage time. At the same absorbed dose, RIC increases as preirradiation urea concentration increases. The RIC change of aqueous urea solutions reaches a maximum value at 3.5 M aqueous urea solutions. RIC of 0.133 and 3.5 M aqueous urea solutions as a function of dose, have been investigated in the range between 2.18 and 119.4 kGy. RIC of the 0.133 and 3.5 M aqueous urea solutions increased linearly with increasing dose (R 2 =0.9963, 0.9972 respectively). The calibration factors was found to be 2.1448 and 9.53 μS/kGy for sets with 0.133 and 3.5 M urea respectively .The coefficient of variation CV %, associated with RIC measurement of 3.5 M aqueous urea solution as a function of absorbed radiation dose was found to be 1.8025% and the uncertainty was found to be 3.6 % and 5.4 % for 95 % and 99 % confidence levels, respectively. The effective atomic number of 3.5 M aqueous urea solutions is 6.58, which indicates tissue equivalency of this system. The RIC values of 3.5 M aqueous urea solutions were found to be relatively stable over storage period of three weeks at 0 degree C. Accordingly, this system could be considered as a promising radiation-sensitive material for dosimetry of gamma rays in both technical and research fields

Chemistry in high temperature aqueous solutions application to the power industry

International Nuclear Information System (INIS)

Cohen, P.

1990-01-01

The power industry utilizes water (aqueous solutions) for two main functions: as a medium for heat transfer and transport and as a thermodynamic working fluid. These functions are performed in systems fabricated from a wide variety of materials, over a wide range of thermal and hydraulic conditions, and at medium temperatures and densities which determine the significant chemical properties. The major chemical interest is in the concentrated solutions derived from the dilute working fluid at selected sites defined by the physical arrangement and temperature and in their consequential effects on heat transfer and corrosion. Examples of these sites for typical fossil fired and nuclear steam generating equipment are described, as well as the extent and limit of the concentration process. The history of steam power plant water chemistry is discussed from the point of view of the chemical processes involved. The period covered is from the 1920s to the present state of the art, which is a major application of the subject of this symposium--chemistry in high temperature aqueous solution

Study of the physicochemical properties of the interface between titanium dioxide and various aqueous solutions

International Nuclear Information System (INIS)

Mazilier, C.

1988-01-01

The aim of this work is the study of ion exchange capacity of titanium dioxide in view of high temperature water purification and radioactive effluent processing because of its resistance to heat and radiations. Titanium dioxide is obtained by alkaline hydrolysis of an aqueous solution of Ti (IV) and is characterized by analytical physical chemistry methods. Interface between Ti0 2 and simple aqueous solutions (electrolytes) is more particularly studied by potentiometry [fr

Plasma induced degradation of benzidine in aqueous solution

International Nuclear Information System (INIS)

Gao Jinzhang; Gai Ke; Yang Wu; Dong Yanjie

2003-01-01

The degradation of benzidine in aqueous solution by the low temperature plasma was examined. The results showed that the concentration of medium and the value of pH have an appreciable effect on the degradation of benzidine. What is more important is that iron ions acting as a catalyst play an important role in this reaction. For exploring the degradation mechanism of benzidine, some of the intermediate products were recorded by HPLC (high performance liquid chromatography)

Heterogeneity of activated carbons in adsorption of aniline from aqueous solutions

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Podkościelny, P.; László, K.

2007-08-01

The heterogeneity of activated carbons (ACs) prepared from different precursors is investigated on the basis of adsorption isotherms of aniline from dilute aqueous solutions at various pH values. The APET carbon prepared from polyethyleneterephthalate (PET), as well as, commercial ACP carbon prepared from peat were used. Besides, to investigate the influence of carbon surface chemistry, the adsorption was studied on modified carbons based on ACP carbon. Its various oxygen surface groups were changed by both nitric acid and thermal treatments. The Dubinin-Astakhov (DA) equation and Langmuir-Freundlich (LF) one have been used to model the phenomenon of aniline adsorption from aqueous solutions on heterogeneous carbon surfaces. Adsorption-energy distribution (AED) functions have been calculated by using an algorithm based on a regularization method. Analysis of these functions for activated carbons studied provides important comparative information about their surface heterogeneity.

Adsorptive removal of malachite green from aqueous solutions by almond gum: Kinetic study and equilibrium isotherms.

Science.gov (United States)

Bouaziz, Fatma; Koubaa, Mohamed; Kallel, Fatma; Ghorbel, Rhoudha Ellouz; Chaabouni, Semia Ellouz

2017-12-01

This work aimed at investigating the potential of almond gum as low cost adsorbent for the removal of the cationic dye; malachite green from aqueous solutions. Almond gum was first analyzed by scanning electron microscopy (SEM) and Fourier transforms infrared spectroscopy (FTIR), and then the adsorption behavior was studied in batch system. The effects of the adsorption parameters (adsorbent dose, pH, contact time, particle size, initial dye concentration, temperature and agitation) on the dye removal have been studied. Adsorption equilibrium and isotherms were evaluated depending on temperature using the isotherms of Freundlich, Langmuir, and Tempkin. The obtained result showed that both Langmuir and Freundlich models were adapted to study the dye sorption. The maximum adsorption capacities were equal to 172.41mg/g, 181.81mg/g, and 196.07mg/g at 303.16K, 313.16K, and 323.16K, respectively. The kinetics of sorption were following the pseudo-second order model. The thermodynamic changes in enthalpy (ΔH), entropy (ΔS), and free energy (ΔG) indicated that the adsorption of malachite green at the surface of almond gum is endothermic and occurs spontaneously. Desorption experiments were conducted to regenerate almond gum, showing great desorption capacity when using HCl at pH 2. Copyright © 2017 Elsevier B.V. All rights reserved.

[Effect of 60Co gamma-irradiation on dilute aqueous solutions of surfactants].

Science.gov (United States)

Sawai, T; Shimokowa, T; Miki, Y; Oseko, K; Sawai, T

1978-01-01

Present work deals with the effects of gamma irradiation from 60Co gamma-ray source upon aqueous solutions of three kinds of surfactants. When dilute aqueous solutions of sodium dodecyl sulfate (SDS, anionic), cethyl trimethyl ammonium chloride (CTAC, cationic), and polyoxyethylene lauryl ether (POE, non-ionic) were irradiated with gamma-rays at a room remperature, the residual concentration, products, surface tension, and forming power were examined by colorimetric method, IR spectrophotometric method, gaschromatography, Ross-Miles method, and Traube's stalagnometer etc.. These surfactants were decomposed by the irradiation and thus the surface tension increased and the forming power, on the contrary, decreased with dose. Radiation chemical yields (G-value) of the degradation were about 1 for the solutions of SDS and CTAC, and about 0.3 for the POE solution. From the experimental results, it was found that following chemical reactions seem to occur followed by the radiolysis of water; a) bond cleavage of ester for SDS, of CN for CTAC, and of oxyethylene for POE, b) hydrogen abstraction from the surfactants, c) production of CO bond in the presence of dissolved oxygen.

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

OpenAIRE

Moreno-Piraj?n, Juan Carlos; Blanco, Diego; Giraldo, Liliana

2011-01-01

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-so...

Oxygen effect in the radiolysis of triton X-100 aqueous solution

International Nuclear Information System (INIS)

Perkowski, J.; Mayer, J.

1994-01-01

Experiments with Triton X-100 as a model surfactant were performed under steady-state conditions, using deoxygenated solutions as well as those saturated with N 2 O, O 2 or N 2 O/O 2 mixtures. The Triton x-100 decomposition yield was dependent on the O 2 content of the irradiated system. Oxygen promoted surfactant decomposition in aqueous solution containing only Triton X-100. (author) 13 refs.; 1 tab

Thermodynamic studies of drug–α-cyclodextrin interactions in water at 298.15 K: Procaine hydrochloride/lidocaine hydrochloride/tetracaine hydrochloride/ranitidine hydrochloride + α-cyclodextrin + H2O systems

International Nuclear Information System (INIS)

Shaikh, Vasim R.; Terdale, Santosh S.; Hundiwale, Dilip G.; Patil, Kesharsingh J.

2014-01-01

Graphical abstract: The encapsulation of guest tetracaine hydrochloride TC·HCl (C 15 H 24 N 2 O 2 ·HCl), in α-cyclodextrin cavities in aqueous solutions at 298.15 K. -- Highlights: • The osmotic coefficient measurements are reported for PC·HCl/LC·HCl/TC·HCl/RT·HCl + 0.1 m α-CD + water at 298.15 K. • The concentration variation of mean activity coefficients of drug molecules in water–α-CD solutions has been studied. • The transfer Gibbs free energies have been calculated using the activity data. • Pair and triplet interaction parameters and equilibrium constant (log K) values are also estimated. • The results are discussed with emphasis on host–guest interaction concepts. -- Abstract: The osmotic coefficient measurements have been carried out for ternary aqueous solutions containing a fixed concentration of α-cyclodextrin (α-CD) of ∼0.1 mol · kg −1 and varying the concentrations (∼0.012 to ∼0.21 mol · kg −1 ) of drugs Procaine hydrochloride (PC·HCl), Lidocaine hydrochloride (LC·HCl), Tetracaine hydrochloride (TC·HCl) and Ranitidine hydrochloride (RT·HCl) at 298.15 K using vapour pressure osmometry. The water activities for each ternary system were measured and used to obtain the activity coefficients of α-cyclodextrin (α-CD) and drugs following the methodology developed by Robinson and Stokes for isopiestic measurements. The transfer Gibbs free energies of electrolyte (or drug) from water to an aqueous nonelectrolyte (α-CD) solutions (ΔG tr E ) and that of nonelectrolyte (α-CD) from water to an aqueous electrolyte (or drug) solutions (ΔG tr N ) have been calculated using the activity data. These were further used for the estimation of pair and triplet interaction parameters. By applying the method based on the application of the McMillan–Mayer theory of virial coefficients to transfer free energy data, the salting constant (k s ) values have been estimated at 298.15 K. The equilibrium constant (log K) values for the

Graph Theory and Ion and Molecular Aggregation in Aqueous Solutions

Science.gov (United States)

Choi, Jun-Ho; Lee, Hochan; Choi, Hyung Ran; Cho, Minhaeng

2018-04-01

In molecular and cellular biology, dissolved ions and molecules have decisive effects on chemical and biological reactions, conformational stabilities, and functions of small to large biomolecules. Despite major efforts, the current state of understanding of the effects of specific ions, osmolytes, and bioprotecting sugars on the structure and dynamics of water H-bonding networks and proteins is not yet satisfactory. Recently, to gain deeper insight into this subject, we studied various aggregation processes of ions and molecules in high-concentration salt, osmolyte, and sugar solutions with time-resolved vibrational spectroscopy and molecular dynamics simulation methods. It turns out that ions (or solute molecules) have a strong propensity to self-assemble into large and polydisperse aggregates that affect both local and long-range water H-bonding structures. In particular, we have shown that graph-theoretical approaches can be used to elucidate morphological characteristics of large aggregates in various aqueous salt, osmolyte, and sugar solutions. When ion and molecular aggregates in such aqueous solutions are treated as graphs, a variety of graph-theoretical properties, such as graph spectrum, degree distribution, clustering coefficient, minimum path length, and graph entropy, can be directly calculated by considering an ensemble of configurations taken from molecular dynamics trajectories. Here we show percolating behavior exhibited by ion and molecular aggregates upon increase in solute concentration in high solute concentrations and discuss compelling evidence of the isomorphic relation between percolation transitions of ion and molecular aggregates and water H-bonding networks. We anticipate that the combination of graph theory and molecular dynamics simulation methods will be of exceptional use in achieving a deeper understanding of the fundamental physical chemistry of dissolution and in describing the interplay between the self-aggregation of solute

Graph Theory and Ion and Molecular Aggregation in Aqueous Solutions.

Science.gov (United States)

Choi, Jun-Ho; Lee, Hochan; Choi, Hyung Ran; Cho, Minhaeng

2018-04-20

In molecular and cellular biology, dissolved ions and molecules have decisive effects on chemical and biological reactions, conformational stabilities, and functions of small to large biomolecules. Despite major efforts, the current state of understanding of the effects of specific ions, osmolytes, and bioprotecting sugars on the structure and dynamics of water H-bonding networks and proteins is not yet satisfactory. Recently, to gain deeper insight into this subject, we studied various aggregation processes of ions and molecules in high-concentration salt, osmolyte, and sugar solutions with time-resolved vibrational spectroscopy and molecular dynamics simulation methods. It turns out that ions (or solute molecules) have a strong propensity to self-assemble into large and polydisperse aggregates that affect both local and long-range water H-bonding structures. In particular, we have shown that graph-theoretical approaches can be used to elucidate morphological characteristics of large aggregates in various aqueous salt, osmolyte, and sugar solutions. When ion and molecular aggregates in such aqueous solutions are treated as graphs, a variety of graph-theoretical properties, such as graph spectrum, degree distribution, clustering coefficient, minimum path length, and graph entropy, can be directly calculated by considering an ensemble of configurations taken from molecular dynamics trajectories. Here we show percolating behavior exhibited by ion and molecular aggregates upon increase in solute concentration in high solute concentrations and discuss compelling evidence of the isomorphic relation between percolation transitions of ion and molecular aggregates and water H-bonding networks. We anticipate that the combination of graph theory and molecular dynamics simulation methods will be of exceptional use in achieving a deeper understanding of the fundamental physical chemistry of dissolution and in describing the interplay between the self-aggregation of solute

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

Science.gov (United States)

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

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Liliana Giraldo

2011-12-01

Full Text Available 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.

Vibrational dynamics of aqueous hydroxide solutions probed using broadband 2DIR spectroscopy

International Nuclear Information System (INIS)

Mandal, Aritra; Tokmakoff, Andrei

2015-01-01

We employed ultrafast transient absorption and broadband 2DIR spectroscopy to study the vibrational dynamics of aqueous hydroxide solutions by exciting the O–H stretch vibrations of the strongly hydrogen-bonded hydroxide solvation shell water and probing the continuum absorption of the solvated ion between 1500 and 3800 cm −1 . We observe rapid vibrational relaxation processes on 150–250 fs time scales across the entire probed spectral region as well as slower vibrational dynamics on 1–2 ps time scales. Furthermore, the O–H stretch excitation loses its frequency memory in 180 fs, and vibrational energy exchange between bulk-like water vibrations and hydroxide-associated water vibrations occurs in ∼200 fs. The fast dynamics in this system originate in strong nonlinear coupling between intra- and intermolecular vibrations and are explained in terms of non-adiabatic vibrational relaxation. These measurements indicate that the vibrational dynamics of the aqueous hydroxide complex are faster than the time scales reported for long-range transport of protons in aqueous hydroxide solutions

Extraction of rare earth metals (3) from aqueous solutions containing thorium and uranyl nitrates

International Nuclear Information System (INIS)

Pyartman, A.K.; Kopyrin, A.A.; Berinskij, A.E.; Keskinov, V.A.

2000-01-01

Isotherms of extraction of rare earth metals (3) from aqueous solutions containing thorium and uranyl nitrates by solutions of tributylphosphate (TBP) and diisooctylmethylphosphonate (DIOMP) in kerosene at 298.15 Deg C and pH 1 are presented. Equations for description of interphase distribution of components of the systems considered are suggested. These equations describe distribution of components adequately in the systems of thorium nitrate (uranyl nitrate) - rare earth nitrates - (TBP, DIOMP) in the case of wide variation of phase compositions. Dependences of separation factors on composition of aqueous phase are considered [ru

A highly sensitive fluorescent probe based on BODIPY for Hg2+ in aqueous solution

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ZHAO Junwei

2016-12-01

Full Text Available A highly sensitive fluorescent probe based on BODIPY and hydrazine for Hg2+ was designed and synthesized.This probe could detect mercury ions in aqueous solutions within 5 min.With the increase of Hg2+ mole concentration,an obvious red shift of UV-Vis absorption wavelength was observed and the fluorescence intensity significantly enhanced.It was found that the fluorescence intensity of an aqueous solution containing 0.1 μmol/L Hg2+ is much stronger than that of blank solution,which indicats that the fluorescent probe has high sensitivity.In addition,other metal ions could not cause the change of fluorescent spectra,which means this probe has good selectivity,as well.

Are nanoscale ion aggregates present in aqueous solutions of guanidinium salts?

Science.gov (United States)

Hunger, Johannes; Niedermayer, Stefan; Buchner, Richard; Hefter, Glenn

2010-11-04

A detailed investigation using broadband dielectric relaxation spectroscopy (DRS) has been made of the aqueous solutions of guanidinium chloride and carbonate, GdmCl(aq) and Gdm₂CO₃(aq), at 25 °C. The spectra indicate that Gdm(+) ions, C(NH₂)₃(+), do not bind strongly to water nor are they hydrophobically hydrated; rather they appear to have a most unusual ability to dissolve in water without altering its dynamics. Although DRS is particularly sensitive to the presence of ion pairs, only weak ion pairing was detected in Gdm₂CO₃(aq) solutions and none at all in GdmCl(aq). Surprisingly, no evidence was found for the existence of the higher order homo- and heteroionic nanoscale aggregates that have been identified in recent years by Mason and co-workers using molecular dynamics simulations and neutron diffraction. Possible reasons for this discrepancy are discussed. The present DR spectra and other solution properties of GdmCl(aq) and Gdm₂CO₃(aq), such as apparent molar volumes and electrical conductivities, are shown to have strong similarities to those of the corresponding Na+ salts. However, such solutions also differ remarkably from their Na(+) analogues (and all other simple electrolytes in aqueous solution) in that their average water relaxation times correlate strongly with their bulk viscosities. The biological implications of the present results are briefly discussed.

Volumetric, ultrasonic and viscometric studies of solute–solute and solute–solvent interactions of l-threonine in aqueous-sucrose solutions at different temperatures

International Nuclear Information System (INIS)

Nain, Anil Kumar; Pal, Renu; Neetu

2013-01-01

Highlights: • The study reports density, ultrasonic speed and viscosity data of l-threonine in aqueous-sucrose solutions. • The study elucidates interactions of l-threonine with sucrose in aqueous media. • Provides data to estimate physicochemical properties of proteins in these media. • Correlates physicochemical properties of l-threonine with its behaviour in aqueous-sucrose solutions. -- Abstract: Densities, ρ of solutions of l-threonine in aqueous-sucrose solvents 5%, 10%, 15%, and 20% of sucrose, w/w in water at T = (293.15, 298.15, 303.15, 308.15, 313.15, and 318.15) K; and ultrasonic speeds, u and viscosities, η of these solutions at 298.15, 303.15, 308.15, 313.15, and 318.15 K were measured at atmospheric pressure. From these experimental results, the apparent molar volume, V ϕ , limiting apparent molar volume, V ϕ ∘ and the slope, S v , apparent molar compressibility, K s,ϕ , limiting apparent molar compressibility, K s,ϕ ∘ and the slope, S k , transfer volume, V ϕ,tr ∘ , transfer compressibility, K s,ϕ,tr ∘ , limiting apparent molar expansivity, E ϕ ∘ , Hepler’s constant, (∂ 2 V ϕ ∘ /dT 2 ), Falkenhagen coefficient, A, Jones–Dole coefficient, B and hydration number, n H have been calculated. The results have been interpreted in terms of solute–solvent and solute–solute interactions in these systems. The Gibbs energies of activation of viscous flow per mole of solvent, Δμ 1 ∘number sign and per mole of solute, Δμ 2 ∘number sign were also calculated and discussed in terms of transition state theory. It has been observed that there exist strong solute–solvent interactions in these systems and these interactions increase with increase in sucrose concentration in solution

Unusual radiolytic behavior of neptunium ions in aqueous bicarbonate solutions

International Nuclear Information System (INIS)

Shilov, V.P.; Gogolev, A.V.; Pikaev, A.K.

2000-01-01

Behavior of neptunium ions in carbonate and bicarbonate aqueous solutions saturated with air, oxygen or argon during gamma radiation ( 60 Co) by doses up to 3 kGy at dose rates 10 and 25 Gy/min was studied by the method of spectrophotometry. It is shown that in neptunium (5) bicarbonate solution nearly complete (95%) neptunium ion oxidation occurs under the effect of radiation, whereas no oxidation is observed in carbonate solution. Radiation-chemical yield of neptunium (5) oxidation and stationary concentration of neptunium (6) ions depend on concentration of bicarbonate-ions. Explanation to the results obtained is made from the viewpoint of potential radiolytic reactions [ru

Some reactions of oxidizing radicals with enzymes in aqueous solution

International Nuclear Information System (INIS)

Cundall, R.B.; Bisby, R.H.; Hoe, S.T.; Sims, H.E.; Anderson, R.F.

1979-01-01

A range of oxidizing radicals including some inorganic radical anions and the superoxide radical, can be generated by radiolysis of aqueous solutions. These radicals are more selective in their reactions with amino acids than the hydroxyl radical. Factors controlling the apparent reactivity of radical anions with proteins, such as free radical equilibria and ion-binding, are described. The superoxide radical inactivates papain by reaction with the cysteine residue. This reaction has been studied in solutions subjected to radiations of varying linear energy transfer. (Auth.)

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

Energy Technology Data Exchange (ETDEWEB)

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 desired 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.

Physicochemical analysis of cryocrystallization processes of aqueous solutions of yttrium, barium, copper nitrates and their mixtures

International Nuclear Information System (INIS)

Kulakov, A.B.; Mozhaev, A.P.; Tesker, A.M.; Churagulov, B.R.

1992-01-01

Products of fast hardening of aqueous solutions of different concentration of yttrium, barium copper nitrates and their mixtures including mixture of three nitrates with molar ratio equal to 1:2:3 used for synthesis of YBa 2 Cu 3 O 7-x HTSC by cryochemical technique, in liquid nitrogen, are studied using low-temperature, differential thermal and X-ray phase analyses. Aqueous solutions of barium, copper, yttrium nitrates are shown to belong to three different classes which differ in behaviour at fast cooling and subsequent slow heating. Cryogranulate at YBa 2 Cu 2 O 7-x synthesis using cryochemical technique represents mixture of X-ray amorphous Ba(NO 3 ) 2 , crystalline Cu(NO 3 ) 2 ·6H 2 O and ice, as well as, supercooled aqueous solution of yttrium and copper nitrates

Characterization of aqueous silver nitrate solutions for leakage tests

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José Ferreira Costa

2011-06-01

Full Text Available OBJECTIVE: To determine the pH over a period of 168 h and the ionic silver content in various concentrations and post-preparation times of aqueous silver nitrate solutions. Also, the possible effects of these factors on microleakage test in adhesive/resin restorations in primary and permanent teeth were evaluated. MATERIAL AND METHODS: A digital pHmeter was used for measuring the pH of the solutions prepared with three types of water (purified, deionized or distilled and three brands of silver nitrate salt (Merck, Synth or Cennabras at 0, 1, 2, 24, 48, 72, 96 and 168 h after preparation, and storage in transparent or dark bottles. Ionic silver was assayed according to the post-preparation times (2, 24, 48, 72, 96, 168 h and concentrations (1, 5, 25, 50% of solutions by atomic emission spectrometry. For each sample of each condition, three readings were obtained for calculating the mean value. Class V cavities were prepared with enamel margins on primary and permanent teeth and restored with the adhesive systems OptiBond FL or OptiBond SOLO Plus SE and the composite resin Filtek Z-250. After nail polish coverage, the permanent teeth were immersed in 25% or 50% AgNO3 solution and the primary teeth in 5% or 50% AgNO3 solutions for microleakage evaluation. ANOVA and the Tukey's test were used for data analyses (α=5%. RESULTS: The mean pH of the solutions ranged from neutral to alkaline (7.9±2.2 to 11.8±0.9. Mean ionic silver content differed depending on the concentration of the solution (4.75±0.5 to 293±15.3 ppm. In the microleakage test, significant difference was only observed for the adhesive system factor (p=0.000. CONCLUSIONS: Under the tested experimental conditions and based on the obtained results, it may be concluded that the aqueous AgNO3 solutions: have neutral/alkaline pH and service life of up to 168 h; the level of ionic silver is proportional to the concentration of the solution; even at 5% concentration, the solutions were

Kinetika Hidrolisis Pati Biji Nangka (Artocarpus heterophyllus Menggunakan Katalisator Asam Klorida (HCl

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Sri Endang

2014-07-01

Full Text Available The research of kinetic hydrolysis from the starch of jackfruit seed (Artocarpus heterophyllus used clorid acid catalyst (HCl aims to know the influence of variation of concentration HCl catalyst which give the maximum result of hydrolysis of the starch of jackfruit seed, determining the optimum concentration of HCl catalyst that produces the maximum value of the reaction rate constants, and determine the value of the reaction rate constant of hydrolysis the starch of jackfruit seed using catalyst. The method of this research has done in two stages that are the determination of the optimum catalyst concentration of HCl hydrolysis reaction of the starch of jackfruit seed using various concentration of catalyst HCl 0,5 M; 1,0 M; 1,5 M; 2,0 M and 2,5 M at the optimum temperature and stirring time (90oC during 70 minutes. Hydrolysis followed by neutralization process using sodium hydroxide solution and evaporated to get the form of glucose concentrated, that glucose is analyzed by qualitative and quantitative with Benedict experiment and fenol sulphate acid method, based on maximum degree of glucose which is gotten from the result of hydrolysis the starch of jackfruit seed variation concentration oh HCl is in HCl 1,5 M concentration with degree of glucose (% weight is 7,54% with percentage of starch conversion is 83,21%. Second step is determining the value of hydrolysis constant rate reaction which use time variation (30, 40,50, 60 and 70 minutes in 70 minutes optimum operation condition, 90oC te mperature and concentration catalyst of HCl 1,5 M. Based on statistic calculation date of ANOVA is gained F hitung < F tabel so Ho receive and reject HI  which shows that there is not influence catalyst variation concentration of HCl to the result of hydrolysis the starch of jackfruit seed which is gained. The result of the research shows that hydrolysis of kinetic of the starch of jackfruit seeduse HCl catalyst is reaction of the first apparent orde with

Determination of Ga in aqueous uranium solution by EDXRF

International Nuclear Information System (INIS)

Natarajan, V.; Purohit, P.J.; Goyal, Neelam; Seshagiri, T.K.; Godbole, S.V.; Manchanda, V.K.

2009-01-01

A method has been developed using EDXRF technique for the determination of gallium in aqueous solution using a set of solution standards in the concentration range 20-5000 μg/ml. When this method was applied to U containing solutions, the estimated values were found to be lower due to matrix effects. Hence the method was modified in order to determine gallium in the presence of uranium using lower tube current and another set of standards with U concentration at 100 mg/ml. The method was applicable for the estimation of Ga from 50 μg/ml to 5mg/ml (i.e.0.05-5% Ga in U). Three synthetic samples were analysed by the present methods in order to evaluate the method for its reliability and reproducibility. (author)

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

Science.gov (United States)

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.

Removal of cadmium(II) from aqueous solutions by steam-activated ...

African Journals Online (AJOL)

Removal of cadmium(II) from aqueous solutions by steam-activated sulphurised carbon prepared from sugar-cane bagasse pith: kinetics and equilibrium studies. ... the maximum adsorption capacity of SA-S-C calculated by the Langmuir isotherm is 149.93 mg/g at 30°C. Acid regeneration was tried for several cycles with a ...

Kinetics of absorption of carbon dioxide in aqueous ammonia solutions

NARCIS (Netherlands)

Derks, P. W. J.; Versteeg, G. F.

2009-01-01

In the present work the absorption of carbon dioxide into aqueous ammonia solutions has been studied in a stirred cell reactor, at low temperatures and ammonia concentrations ranging from 0.1 to about 7 kmol m-3. The absorption experiments were carried out at conditions where the so-called pseudo

Equilibrium Sorption Studies of Hg (II) Ions from Aqueous Solution ...

African Journals Online (AJOL)

The potential of swamp arum (Lasimorpha senegalensis) seeds as a low-cost adsorbent for the removal of Hg (II) ions from aqueous solution was investigated in this study. The influence of initial metal concentration on the percent adsorption of Hg (II) ions onto powdered swamp arum seeds was studied in a batch system ...

The solubility of hydrogen sulfide in aqueous N-methyldiethanolamine solutions

NARCIS (Netherlands)

Huttenhuis, P.J.G.; Agrawal, N.J.; Versteeg, G.F.

2008-01-01

In this work the electrolyte equation of state as developed previously for the system MDEA-H2O-CO2-CH4 was further developed for the system MDEA-H2O-H2S-CH4. With this thermodynamic equilibrium model the total solubility of hydrogen sulfide and the speciation in aqueous solutions of

Formation of the second organic phase during uranyl nitrate extraction from aqueous solution by 30% tributylphosphate solution in paraffin

International Nuclear Information System (INIS)

Yhrkin, V.G.

1996-01-01

For extraction systems aqueous solution of uranyl nitrate-30% solution of tributylphosphate in individual paraffins from C 13 to C 17 the influence of the second organic phase of uranyl nitrate concentration in aqueous and organic phases, the length of hydrocarbon chain of paraffin hydrocarbon and temperature from 25 to 50 deg C on formation conditions has been defected. A special method of achieving the conditions of organic phase stratification from three-phase region, involving definition of equilibrium phases composition by density and refractive index, has been elaborated for more precise definition of organic phase homogeneity region. It has been revealed that without addition of nitric acid to uranyl nitrate solution the organic phase homogeneity limits can be achieved solely on paraffins C 15 , C 16 and C 17 and only under conditions similar to equeous phase saturation in terms of uranyl nitrate. 16 refs., 2 figs

RECOVERY OF CARBOXYLIC ACIDS FROM AQUEOUS SOLUTIONS BY LIQUID-LIQUID EXTRACTION WITH A TRIISOOCTYLAMINE DILUENT SYSTEM

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G. Malmary

2001-12-01

Full Text Available Tertiary alkylamines in solution with organic diluents are attractive extractants for the recovery of carboxylic acids from dilute aqueous phases. The aim of this study was to investigate the mechanism for extraction of organic acids from water by a long-chain aliphatic tertiary amine. In order to attain this objective, we studied the liquid-liquid equilibria between the triisooctylamine + 1-octanol + n-heptane system as solvent and an aqueous solution of an individual carboxylic acid such as citric, lactic and malic acids. The experiments showed that the partition coefficient for a particular organic acid depends on the kind of solute, notably when the acid concentration in the aqueous phase is low. A mathematical model, where both chemical association and physical distribution are taken into consideration, is proposed. The model suggests that the various complexes obtained between amine and organic acids contribute to the distribution of the solute between the coexisting phases in equilibrium.

Radiation crosslinking of methylcellulose and hydroxyethylcellulose in concentrated aqueous solutions

International Nuclear Information System (INIS)

Wach, Radoslaw A.; Mitomo, Hiroshi; Nagasawa, Naotsugu; Yoshii, Fumio

2003-01-01

The effects of ionizing radiation on aqueous solutions of cellulose ethers, methylcellulose (MC) and hydroxyethylcellulose (HEC) were investigated. The well-established knowledge states that cellulose and its derivatives belong to degrading type of polymers. However, in our study intermolecular crosslinking initiated by gamma rays or electron beam leaded to the formation of insoluble gel. This is an opposite effect of irradiation to the degradation. Paste-like form of the initial specimen, i.e. concentration 20-30%, when water plasticizes the bulk of polymer; and a high dose rate were favorable for hydrogel formation. Gel fraction up to 60% and 70% was obtained from solutions of HEC and MC, respectively. Produced hydrogels swell markedly in aqueous media by imbibing and holding the solvent. Radiation parameters of irradiation, such as yields of degradation and crosslinking and the gelation dose, were evaluated by sol-gel analysis on the basis of Charlesby-Rosiak equation. Despite of the crosslinked structure, obtained hydrogels can be included into the group of biodegradable materials. They undergo decomposition by the action of cellulase enzyme or microorganisms from compost

Application of Homotopy-Perturbation Method to Nonlinear Ozone Decomposition of the Second Order in Aqueous Solutions Equations

DEFF Research Database (Denmark)

Ganji, D.D; Miansari, Mo; B, Ganjavi

2008-01-01

In this paper, homotopy-perturbation method (HPM) is introduced to solve nonlinear equations of ozone decomposition in aqueous solutions. HPM deforms a di¢ cult problem into a simple problem which can be easily solved. The effects of some parameters such as temperature to the solutions are consid......In this paper, homotopy-perturbation method (HPM) is introduced to solve nonlinear equations of ozone decomposition in aqueous solutions. HPM deforms a di¢ cult problem into a simple problem which can be easily solved. The effects of some parameters such as temperature to the solutions...

Dynamical structure of water in aqueous solutions of D-glucose and D-galactose by low-frequency Raman scattering

Science.gov (United States)

Wang, Yan; Tominaga, Yasunori

1994-02-01

Low-frequency depolarized Raman spectra of aqueous solutions of D-glucose and D-galactose have been investigated in the frequency region from -250 cm-1 to 250 cm-1 at 30.0 °C as a function of concentration up to 0.04 molar ratio. The dynamical structure of water in aqueous solution is analyzed by using the reduced Raman spectrum χ`(ν¯), which corresponds to the imaginary part of the dynamical susceptibility. The reduced spectrum is fitted with the superposition of one Cole-Cole type relaxation mode and two damped harmonic oscillator modes by a nonlinear least-squares fitting. The effects of D-glucose and D-galactose on the dynamical structure of water in aqueous solution are similar. The relaxation time of hydrogen bond among water molecules becomes slower with increasing sugar concentration. The characteristic frequencies of stretching-like and bending-like vibrations among water molecules do not change in both D-glucose and D-galactose aqueous solutions.

Probing Ionic Liquid Aqueous Solutions Using Temperature of Maximum Density Isotope Effects