Solvent Impregnated Resin for Selective Recovery of Palladium from Spent Automotive Catalyst Leach Solutions

Abstract

The increasing demand for palladium in automotive, electronic, and catalytic applications has intensified the need for efficient recovery technologies from secondary resources such as spent automotive catalysts. This study investigates the application of solvent impregnated resin (SIR) technology for the selective recovery of palladium from spent automotive catalyst leach solutions. The process combines the advantages of solvent extraction and ion exchange to achieve enhanced metal selectivity, operational stability, and reduced solvent consumption. Experimental studies were conducted to evaluate the influence of parameters including resin loading, contact time, pH, temperature, and initial metal ion concentration on palladium adsorption and recovery efficiency. The impregnated extractant demonstrated strong affinity toward palladium ions while minimizing the co-extraction of competing metals commonly present in catalyst leachates, such as platinum, rhodium, iron, and base metals. Adsorption kinetics and equilibrium behavior were analyzed using suitable isotherm and rate models to understand the interaction mechanism between palladium ions and the functionalized resin matrix. The results revealed that the solvent impregnated resin achieved high palladium recovery with excellent selectivity and reusability over multiple extraction–stripping cycles. Furthermore, the process exhibited lower chemical consumption and reduced secondary waste generation compared to conventional hydrometallurgical separation methods.