Selenium oxyanions; Highly selective uptake by a novel anion exchanger

Kozai, Naofumi   ; Onuki, Toshihiko; Komarneni, S.*

Here we report the extremely high and selective uptake of selenium oxyanions by a novel exchanger, NiZn(OH)(OCOCH)・nHO that has brucite-type hydroxide layers with OCOCH anions in the interlayers. This Ni-Zn basic salt exhibited very high selectivity for Se(IV) (Kd = 9.0x10 ml/g with an initial Se(IV) concentration of 1x10 M) in the presence of 0.1M Cl solution while the well known anionic clay, MgAl(OH)NO・nHO showed a Kd of 6.0x10 ml/g under the same conditions. The uptake of Se(IV) on the Ni-Zn basic salt was found to be irreversible when treated with solutions containing 1N Cl, 1N NO, or 1N PO, while the Se(IV) sorbed on anionic clay was easily desorbed in a 1M Cl solution. This novel exchanger also showed high Kd (2.610 ml/g at an initial Se concentration of 110 M) for Se(VI) and therefore it is expected to be useful for decontamination and removal of selenium oxyanions from contaminated water.