Analytical Sciences

Improvement of Chromium(VI) Extraction from Acidic Solutions Using a Poly(vinyl chloride)-based Polymer Inclusion Membrane with Aliquat 336 as the Carrier

Shigehiro KAGAYA,* Tomonori MAENO,* Kazuma ITO,* Makoto GEMMEI-IDE,* Robert W. CATTRALL,** and Spas D. KOLEV**

*Graduate School of Science and Engineering for Research, University of Toyama, Toyama 930-8555, Japan
**School of Chemistry, The University of Melbourne, Victoria 3010, Australia

An important reason for the inefficient extraction of Cr(VI) from its acidic solutions into polymer inclusion membranes (PIMs), consisting of poly(vinyl chloride) as the base-polymer and Aliquat 336 as the carrier, was found to be associated with the leaching of Aliquat 336 from the PIMs into the solutions, where it subsequently reduced the anionic Cr(VI) species to cationic Cr(III) species. The PIM extraction efficiency for Cr(VI) was significantly improved by the addition of NaNO₃ to the solutions, which suppressed the leaching of Aliquat 336 and the reduction of Cr(VI) to Cr(III).

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