Noble metals (NM) such as gold, platinum, palladium, and rhodium are widely applied in the electronics and automotive industries. Thus, the search for cheap and selective sorbents for noble metals is economically justified. Nitrolite does not sorb noble metal ions. A new impregnated sorbent was prepared. The natural sorbent Nitrolite was impregnated with Aliquat 336 using a new warm impregnation method. After the impregnation process, Nitrolite adsorbed platinum(IV), palladium(II), and gold(III) ions from the chloride solutions. The values of the sorption capacity for palladium(II) and platinum(IV) ions were 47.63 mg/g and 51.39 mg/g, respectively, from the 0.1 M HCl model solution. The sorption capacity for gold(III) ions was estimated to be 73.43 mg/g from the 0.1 M HCl model solution. An exhausted catalytic converter was leached, and platinum(IV), palladium(II), and rhodium(III) were transferred to the chloride solution. The impregnated sorbent Nitrolite-Aliquat 336 was used in the investigations of the platinum(IV), palladium(II), and rhodium(III) ions' sorption from a real solution. The impregnated sorbent Nitrolite-Aliquat 336 proved to be suitable for the recovery of platinum(IV) and palladium(II) ions, whereas rhodium ions were not sorbed from the leached solutions. Notably, 1 M thiourea in the 1 M HCl solution desorbed platinum(IV), palladium(II), and gold(III) above 94%.
Keywords: Aliquat 336; Nitrolite; green adsorbent; noble metals; warm impregnation.