Extraction of Pd(II), Rh(III) and Ru(III) from HNO3 aqueous solution to betainium bis(trifluoromethanesulfonyl) imide ionic liquid

Extraction efficiencies of Pd(II), Rh(III), and Ru(III) from HNO3(aq) to [Hbet][Tf2N] were demonstrated, i.e., Pd(II) is the most extractable, Rh(III) is medium extractable, and Ru(III) is the least extractable. The extraction seems to proceed through coordination of betaine to the metal ions and the cation exchange of the formed complex with H+.