The study investigates the recovery of platinum-group metals (PGMs), Pd, Pt, and Rh, from secondary
sources - spent catalytic converters, waste from a chemical industry, and a PGM refinery. Aquaregia was
used to create leaching liquors and solid-phase extraction sorbents with different functional groups - DiOctyl Sulfide (DOS), Cyano (CN), Di-Ethylene Tetra-Amine (DETA), and strong anion exchanger (SAX)
- were employed based on the "hard and soft acid and base (HASAB)" principles. The SAX-sorbent
demonstrated the ability to retain PGMs in the presence of accompanying base metals selectively.
In contrast, the DOS and CN sorbents were selective only for Pd, and the DETA sorbent displayed
selectivity solely for Rh. Desorption experiments revealed that 3M HCl could effectively recover the
PGMs from loaded solid-phase sorbents with significant HSE advantages. The study also noted the high
stability of the sorbents, although improvements are needed, particularly in enhancing the reusability
of the DETA-sorbent.
