The quantitative separation of chromium(VI) from other elements with a strongly basic anion-exchange resin

Abstract

Previous work has shown that chromium(VI) on a strongly basic exchange resin in sulphuric acid solution cannot be quantitatively separated from other metal ions because of partial reduction of the chromium(VI) to chromium(III). The present investigations have demonstrated the complete retention of chromium(VI) by the resin in alkaline solutions, thus permitting the separation of chromium from many elements, which can be precipitated as hydroxides, and also from amphoteric elements, which can be eluted from the resin with alkaline solutions. Finally, chromium(VI) can be quantitatively removed from the resin with 8 to 10 per cent. sodium carbonate solution or, more satisfactorily, with an aqueous solution of a mixture of sodium hydrogen carbonate and sodium carbonate.