Arsenic Contamination of Groundwater at the Middle Basin of Ganges in India

This paper shows the situation and mechanism of arsenic contamination of groundwater at the worst contaminated areas in UP (Uttar Pradesh) state, India, which is obtained from the integrated arsenic mitigation project by University of Miyazaki under the Japan International Cooperation Agency (JICA) Partnership Program (JPP). The project has been executed from 2008 until now. The integrated mitigation, such as the raising awareness of villager, installing of alternative water supply units and healthcare of arsenocosis patients, have been executed at the 2 villages. The symptom of the arsenocosis patients was not so severe, which will be, therefore, improved by drinking arsenic-safe water supplied through arsenic removal units, installed by this project. We have obtained following results for the situation and mechanism of arsenic contamination of groundwater, objected in connection with the installation of arsenic removal units:(1) Groundwater is almost contaminated with arsenic in deep tubewell (depth: about 30m), but scarcely in shallow tubewell (depth: about 10m). (2) Arsenic contaminated groundwater is under the reduced condition with the oxidized condition for no-arsenic contaminated groundwater. (3) Arsenic concentration shows almost linear correlation with concentrations of Fe2+ and NH4+-N. (4) Ground is composed of sand with high arsenic content at around 25m depth. (5) Arsenic exists mainly in the phase of reducible fraction or weak acid soluble fraction but no oxidizable fraction in the ground

Adsorption Properties of Au(III) and Cu(II) from Aqueous Solution Using Chemically Treated Sheep Wool

Au(III) and Cu(II) adsorption from aqueous solution were carried out using sheep wools with chemical treatments, by NaOH, Na2S, NaHSO3, and NaBH4 aqueous solution. The fibrous wool was transformed into a film like structures after the chemical treatment using Na2S. The sheep wool and the chemically treated sheep wool adsorbed selectively Au(III) from Au-Cu binary aqueous solution and the presence of copper ion had no effect on the Au(III) adsorption. Au(III) adsorbed substantially at low pH range. The kinetic experimental data fitted well with the pseudo-second-order kinetic model and the adsorption amount of Au(III) increased with time and reached a plateau after 12 h. The kinetic analysis suggests that rate determining step of Au adsorption would be chemisorption due to the formation of a monolayer on the wool surface. Sheep wool is a low cost, eco-friendly material, and has a high capacity of adsorption, and could be used as a biosorbent for precious and heavy metals by modification of appropriate chemical treatment

Thermoresponsive properties of sugar sensitive copolymer of N-isopropylacrylamide and 3-(acrylamido)phenylboronic acid

The copolymer of N-isopropylacrylamide and 3-(acrylamido)phenylboronic acid (82:18, (M) over bar (n)=47000 g. mol(-1)) was prepared by free radical polymerization. The copolymer showed typical thermal precipitation behavior in aqueous solutions, its precipitation temperature (T-P) being increased from 23 to 32degreesC by increasing the pH from 6.5 to 9.7, because of ionization of the phenylboronate units. The pK(a) was evaluated as 8.9+/-0.1 from the effect of pH on T-P. At pH>9, i.e., in the anionic form of the copolymer, T-P was affected by a very low concentration of glucose (5.6 muM, DeltaT(P)=1-1.5degreesC), because of complex formation with a high binding constant. At a higher concentration of polyols (560 muM, pH>8) the increase of T-P was maximal for the copolymer complexes with fructose (7-10degreesC) and decreased in the order: fructose>glucoseapproximate tomannitol>pentaerythritol>galactose>Tris>glycerol. Di- and oligosaccharides (lactose, sucrose, and dextran) caused a slight increase of T-P at pH 7.5-8.7 while no effect was observed at pH>9. Isothermal dissolution of the copolymer suspension in water (27degreesC, pH 8.5) was possible in the. presence of fructose or mannitol but required higher concentrations (1.4-3.6 x 10(3) muM) as compared to those which enabled the shift of T-P in the soluble copolymer. The dissolution rate increased with fructose concentrations

Effects of polyols, saccharides, and glycoproteins on thermoprecipitation of phenylboronate-containing copolymers

The copolymer of 3-(acrylamido)phenyl boronic acid and N-isopropylacrylamide (82:18. M-n = 47000 g/mol) was prepared by free radical polymerization. The copolymer showed typical thermoprecipitation behavior in aqueous solutions; its phase transition temperature (T-p) was 26.5 +/- 0.2 degrees C in 0.1 M glycine-NaOH buffer containing 0.1 M NaCl, pH 9.2. Due to specific complex formation of the pendant boronates with sugars, Tp was strongly affected by the type of sugar and its concentration at pH 9.2. Fructose. lactulose, and glucose caused the largest increase in T-p (up to 4 degrees C) at 0.56 mM concentration, attributed to the high binding affinity of the sugars to borate and phenylboronate. Among the Sugars typical of nonreducing ends of oligosaccharides. N-acetylneuraminic acid had the strongest effect on T-p, (ca. 2 degrees C at 0.56 rnM concentration and pH 9.2), while the effects of other sugars are well expressed at the higher concentrations (16 and 80 rnM) and decreased in the order xylose approximate to galactose >= N-acetyllactosamine >= mannose approximate to fucose >> N-acetylglucosarnine. The effect exerted on the phase transition by glycoproteins was the strongest with mucin from porcine stomach and decreased in the series mucin > horseradish peroxidase > human gamma-globulin at pH 9.2. As a first approximation, the weight percentage and/or the number of oligosaccharides in glycoproteins determined the character of their interaction with the pendant phenylboronates and, therefore, the effect on the copolymer phase transition