Sorption Atomic Emission Determination of Platinum and Palladium in Process Liquors Using the Lewatit AF5 Sorbent

A technique has been developed for determination of platinum and palladium in refining liquors by inductively coupled plasma atomic emission spectrometry (ICP-AES) with preconcentration on a synthetic carbon sorbent. The concentration of the platinum group metals in the solutions studied was below the quantification limit of the ICP-AES method (~0.1 mg/dm3). We have determined the dynamic exchange capacity (DEC) of the sorbent in the case of platinum and palladium preconcentration: the DEC is (0.7–1.6) × 10–3 mg/g for Pt and (0.7–0.9) × 10–3 mg/g for Pd, depending on the type of process liquor. Using the DEC values, we have calculated the effective sorbent weight needed to ensure platinum and palladium recovery, which has been determined to be 155.9 g. To extract platinum and palladium from a test solution, it is passed through a sorbent-packed column for 4 h, and the analytes are eluted with aqua regia and then determined in the eluate by the ICP-AES method. Platinum recovery in the sorption preconcentration step is 98.7–99.3%, depending on the type of solution, and palladium recovery is 98.9–99.7%. The degree of platinum and palladium elution is 98.7 ± 0.3 and 98.8 ± 0.4%, respectively. To assess the adequacy of the proposed technique, model solutions having different concentrations of platinum group metals have been analyzed by inductively coupled plasma mass spectrometry (ICP-MS) as well. The results obtained by the two methods are comparable, which suggests that the proposed technique for sorption atomic emission determination of Pt and Pd can be used as a cheaper alternative to ICP-MS in analysis of refining liquors containing trace levels of platinum group metals.