Retention behaviour of some tri- to hexavalent elements on Dowex 1 and polyurethane foam from hydrochloric acid—potassium thiocyanate medium

Results of a systematic study on the retention behaviour of Au, Fe, Ga, Hf, In, Mo, Nb, Pa, Sb(V), Sc, Sn(IV), Ta, W and Zr on Dowex 1 and polyurethane foam (PUF) in HCl and HClKSCN medium are presented and discussed. In mixed HClKSCN solutions, a very high retention of all the elements studied [except antimony(V) and protacinium] on both materials was found. In the adsorption on PUF, anionic thiocyanate or mixed hydroxo—thiocyanate complexes are favoured. The results can be explained by a cation chelation mechanism. In anion exchange on Dowex 1, the distribution of the elements is realized predominantly either via simple monoligand or mixed polyligand chloro—thiocyanato complex anions. The systems studied offer some attractive possibilities for the preconcentration and separation of many elements. The selective separation of gold with PUF from dilute HCl solutions was tested under dynamic conditions.