Encapsulation of Cyanex 302 with Alginate for Palladium Recovery

A new generation of extractant impregnated resin has been elaborated by encapsulation of extractants in biopolymer capsules. The extractant forms the core of the spherical particle, while the biopolymer entraps the extractant in a shell. The immobilization can reduce the loss of extractant. Cyanex 302 (bis(2,4,4‐trimethylpentyl)monothiophosphinic acid) was efficiently immobilized into alginate capsules prepared by ionotropic gelation in CaCl2 solutions. The influence of a series of parameters on microcapsule preparation was investigated. Selected materials were tested for Pd(II) recovery from HCl solutions through the study of sorption isotherms and uptake kinetics.