In(III) and Ga(III) sorption by polymeric resins with substituted phenylphosphinic acid ligands

The ion-exchange/complexing properties of the resins containing various substituted phenylphosphinic acid ligands towards indium and gallium cations were investigated. Uptake of the above-mentioned cations was done on the resins in acid and ester forms, at different concentration of acid and in the presence of Zn(II) as a competing ion. It was found that resins in an ester form, able only to coordinate metal cations, had very weak affinity towards indium and gallium in the entire range of sulfuric acid concentration, whereas resins in which phosphinic functionality or both phosphinic and carboxylic functionalities were in acid form displayed high affinity towards In(III) and Ga(III). In the latter case, the logarithms of a distribution coefficient were as high as 3.5-4.0 towards Ga(III) and 4.0-6.0 towards In(III) from a 0.1-0.01 M sulfuric acid solutions. The resin may be regenerated using 3 M HCl solutions.