Rhodium(III) Recovery from HCl Solutions Using 4-Alkylaniline-Impregnated Resins

Abstract

In this study, 4-butylaniline-impregnated resins (BuIRs) were prepared by soaking hydrophobic porous resins in aqueous solutions of 4-butylaniline hydrochloride. Rh(III) was successfully adsorbed by BuIRs from 10 ppm Rh(III) solutions (6 M HCl). The quantitative desorption of Rh(III) accompanied with 4-butylaniline hydrochloride from BuIRs was also achieved by Soxhlet extraction using methanol. UV-Vis absorption measurements of Rh(III)-containing solutions showed that the equilibrium shift of Rh(III)-based species in HCl solutions is slow, and heating of the solutions is effective for equilibrating. The BuIRs obtained in this study effectively recovered the Rh(III) chloro-complex anion ([RhCl 6 ] 3 ) from low Rh(III) concentration solutions, and can be useful in the Rh(III) recovery process.

Application of ion-exchange dynamic conditions in the recovery of precious metals from refining waste

“…All experiments showed that rhodium was the most difficult element to recover due to its kinetically inert nature, which results in the largest fluctuation in its sorption efficiency 58 . As already mentioned, in acidic solutions, especially in aqueous chloride solutions, rhodium forms many complexes, such as [RhCl 6 ] 3− , [Rh(H 2 O)Cl 5 ] 2− , [Rh(H 2 O) 2 Cl 4 ] − or [RhCl 6 ] 2− 30 , 59 . Although rhodium can occur in fourth oxidation state, it more often appears in chloride solutions in its third oxidation state, and undergoes solvation.…”