Speciation of Cr(III) and Cr(VI) in tannery wastewater and sediment samples on Ambersorb 563 resin

Abstract

A simple method has been established for speciation of chromium(III) and chromium(VI) in natural water samples. The method is based on the solid phase extraction of the Cr(VI)-APDC chelate on the Ambersorb 563 carbonaceous resin filled mini-column. After oxidation of Cr(III) to Cr(VI) by using H2O2, the method was applied to the determination of the total chromium. The level of Cr(III) is calculated by difference of total chromium and Cr(VI) concentrations. The influences of the various analytical parameters including pH, amounts of reagents, sample volume on the quantitative speciation values of chromium were investigated. Recoveries of more than 95% were found. No interferences due to major components of the natural water samples and some metal ions were observed. The detection limit based on the 3sigma criterion was 2.70 mug/L for Cr(VI). The presented method was applied for the speciation of the chromium in the tannery waste-water samples from Bor Organized Industrial Region-Nigde (Turkey) with satisfactory results (recoveries >95%, RSD's < 9%).