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  • Author or Editor: Xuemei Li x
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Abstract  

The sorption of U(VI) from aqueous solution on MX-80 bentonite was studied as a function of contact time, pH, ionic strength, solid contents, humic acid (HA), fulvic acid (FA) and temperature under ambient conditions using batch technique. The results indicate that sorption of U(VI) on MX-80 bentonite is strongly dependent on pH and ionic strength. The removal of U(VI) to MX-80 bentonite is rather quick and the kinetic sorption data is simulated well by a pseudo-second-order rate equation. The presence of HA enhances the sorption of U(VI) on MX-80 bentonite obviously, but the influence of FA on U(VI) sorption is not obvious. The thermodynamic parameters (ΔH 0, ΔS 0, and ΔG 0) for the sorption of U(VI) calculated from temperature dependent sorption suggest that the sorption reaction is endothermic and spontaneous.

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Abstract  

The mechanism of solvent extraction of gold(III) in hydrochloric acid media with quaternary ammonium salt octadecyl dimethyl benzyl ammonium chloride dissolved in chloroform was studied. The influences of temperature, NaCl and HCl concentraction on the extraction equilibrium were also investigated. The extraction reaction is exothermic (H° = -28.53±0.15 kJ/mol) and log Kex = 5.47±0.04.

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Abstract  

Interfacial tension and interfacial adsorption parameters for benzyloctadecyldimethyl ammonium chloride (BODMAC) in three organic diluents were determined and interpreted. The interfacial activity of BODMAC is affected by the type of the organic diluent and the composition of the aqueous phase. The general order of interfacial activity of BODMAC is n-heptane (5% isobutanol) > carbon tetrachloride > chloroform. The effectiveness of adsorption of BODMAC is not only dependent on the organic diluent, but also on the inorganic electrolytes in the aqueous phase.

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