DISTRIBUTION EQUILIBRIA IN THE ADSORPTION OF COBALT(II) AND NICKEL(II) ON LEVEXTREL RESIN CONTAINING CYANEX 272

Equilibrium distributions of cobalt(II) and nickel(II) were measured in the adsorption on Levextrel resin containing Cyanex 272 as extractant from aqueous ammonium nitrate and sulfate solutions. It was inferred that the extractant in the resin behaves in the same manner as in the solvent extraction. The distribution data were analyzed quantitatively by taking account of the extraction reaction described below to evaluate the apparent equilibrium constants of the extraction reactions for each metal and each aqueous medium as well as the apparent stability constants of cobalt(II)- and nickel(II)-amine complexes. M2++(2+x)H2R2⇌MR2·(2+2x)HR+2h+ where x=0 for cobalt(II) and x=1 for nickel(II). Cobalt(II) is more selectively adsorbed over nickel(II) from sulfate media than from nitrate media though the adsorption itself is suppressed by sulfate anion owing to the formation of metal-sulfato complexes. © 1990.