Studies of removal of platinum (IV) ion microquantities from the model chloride solutions on the ion exchangers of the functional quaternary ammonium groups

Platinum and other platinum metals have been widely applied in industry. The recovery of noble metals from industrial wastes becomes an economic issue. The laboratory studies of removal of platinum (IV) microquantities from 0.1–6M hydrochloric acid solutions on the ion-exchangers of the functional quaternary ammonium groups (Amberlyst A 26, Purolite A 850 and Lewatit MP 500 A) were done. For these ion-exchangers the recovery factor values [%R Pt(IV)] as well as the sorption isotherms depending on the kind of aqueous phase and phase contact time were determined. Moreover, the weight and bed distribution coefficients as well as working and total ionexchange capacities were calculated from the platinum (IV) breakthrough curves. Due to their high ion-exchange capacity in relation to platinum (IV) and great resistance to chemical agents, these ion-exchangers can be applied in technologies of platinum recovery and analysis of its trace amounts.

The strongly basic anion exchangers Amberlyst A 26, Lewatit MP 500 A investigated, owing to their relatively high ion exchange capacity, are suitable for removal of microquantites of platinum (IV) ions from hydrochloric acid solutions. The anion exchanger Purolite A 850 of polyacrylate skeleton can be used for sorption of microquantities of platinum (IV) ions in the hydrochloric acid concentration range 0.1–0.5 M because at higher hydrochloric acid concentrations the working ion exchange capacity is small. Of the studied anion exchangers the gel anion exchanger Purolite A 850 for removal of micro- quantities of platinum (IV) ions from hydrochloric acid solution of a concentration 0.1 M proved to be the most effective. It has a large working capacity value, which is about 342.7 mg Pt(IV)/g under these conditions. In the case of hydrochloric acid solutions in the concentration range from 1 to 6 M the macroporous anion exchangers Amberlyst A 26 and Lewatit MP 500 A are characterized by the largest values of working and total capacities as well as weight and bed distribution coefficients. The choice of suitable anion exchanger depending on the process conditions is necessary in order to obtain a maximal sorption capacity. Platinum (IV) sorbed on an anion exchangers can be recovered after its burning.