Selenium oxyanions: Highly selective uptake by a novel anion exchanger

We report the extremely high and selective uptake of selenium oxyanions by a novel anion exchanger, Ni_1-xZn_2x(OH)₂(OCOCH₃)_2xnH₂O (0.15<x<0.25). The tested Ni–Zn basic salt (x=0.24) exhibited very high selectivity for Se(IV) [K_d = 9.0 × 10⁴ cm³/g with an initial Se(IV) concentration of 1 × 10^-4 M] in the presence of 0.1 M C1⁻ solution. The uptake of Se(IV) on the Ni–Zn basic salt was irreversible when treated with solutions containing 1 N C1⁻ 1N NO₃⁻ or 1 N PO₄³⁻This novel exchanger also showed high K_d (2.6 × 10³ cm³/g) for Se(VI), and therefore it is expected to be useful for decontamination and removal of selenium oxyanions from contaminated water.