Coupled transport of chromium(III) ions across triethanolarnine/cyclohexanone based supported liquid membranes for tannery waste treatment

Coupled transport of Cr(III) ions across TEA-cyclohexanone has been studied with respect to triethanolamine (TEA) concentration in the microporous polypropylene film, sulphate ions in the feed and H2SO4 concentrations in the stripping phase, respectively. Optimum conditions of transport are TEA concentration (5.26 mol/dm(3)) in the liquid membrane, 1.5 mol/dm(3) concentrations of both sulphate ions in the feed and 1.5 mol/dm(3) H2SO4 concentrations in the stripping phase. Ten times decrease in concentration level of Cr(III) ions has been observed practically in the feed solution. The flux has been found to increase with Cr(III) concentration increase in the feed. With sulphate ions increase in the feed, the permeability and distribution coefficient of Cr(III) ions has been found to increase; while, diffusion coefficient and mobility of TEA-Cr(III) complex have been found to decrease. The study indicates the practical aspect of direct transport of Cr(III) ions, without its reduction to Cr(VI). Supported liquid membranes (SLM) technique has been applied to remove Cr(III) ions from tannery effluents, where chromium is present in effluents in the third oxidation state. (c) 2006 Elsevier B.V. All rights reserved.