Recovery of Pd(II) in chloride solutions by solvent extraction with new vinyl sulfide ploymer extractants

Unlike sulfur-containing extractants, extraction efficiency of extractants containing N atoms is often affected by the concentration of H + , but strong affinity of sulfur to Pd(II) may cause stripping process not smoothly. Since sulfur atom conjugated with C C decreases electron cloud density on S atom, a novel polymer extractant containing vinyl sulfide motifs (Poly-EDDYPF) was designed and prepared in this paper, the investigation of this acid resistant extractant shows that the polymer has high extraction efficiency of Pd(II) over 99% with nicely acid resistant. The loading experiment shows that the capacity of Pd(II) of Poly-EDDYPF is up to 268 mg/g. Nearly 95.6% Pd(II) in loaded organic phase could be easily stripped using acid thiourea solution (1 mol/L HCl  + 0.1 mol/L thiourea) and the organic phrase could be reused at least 5 cycles without significant decrease of the extraction efficiency. The optimized conditions for the extraction process are given: [HCl] =1 mol/L, contact time = 20 min, amount of extractant =0.7 g/L, O/A ratio = 1/1. H + concentration and Cl – concentration exhibit practically no effect on extraction efficiency.