THERMODYNAMIC STUDY OF LIQUID-LIQUID EXTRACTION OF ARSENIC(V) BY NMPL FROM H2SO4 MEDIUM.

The results obtained from the extraction of As(V) by 1-(2,6-dimethylheptyl-4-oxy)-3 methyl-1-oxo-Δ3-phospholen (NMPL) are presented in this paper. The conditions of extraction as a function of the extractant and H2SO4 concentrations have been determined. The influence of the extraction of water and sulfuric acid in the extraction process of As(V) has been analyzed. A model of extraction based on the Sergievskii-Dannus' equation has been developed. This model considers the variation of activity coefficients in the aqueous phase and in the organic phase. Thanks to this model its has been possible to predict the theo- retical curves of distribution of H2O, H2SO4 and H3AsO4, in accord with the experimental data. [ABSTRACT FROM AUTHOR]