Recovery of ruthenium by solvent extraction and direct electrodeposition using ionic liquid solution

The electrochemical behavior for Ru(III) in the [P2225][TFSA] was investigated by cyclic voltammetry at 373 K. It was revealed that two step cathodic reactions: Ru(III) + e− → Ru(II) and Ru(II) + 2e− → Ru(0) were proceeded in the [P2225][TFSA] system. Moreover, the potentiostatic electrodeposition allowed us to recover the blackish electrodeposits, which were identified as most of Ru metal by EDX analysis. Finally, we investigated the reuse of the Ru(III) in A336/IL solvent for continuous extraction and electrodeposition. The extraction percentage of Ru(III) using A336/IL remained relatively high (81.5-96.1%) for the 1st − 5th cycles. This series of experimental results enabled us to demonstrate that Ru metal can be obtained from direct electrodeposition of the extracted [R3NH+RuCl4(H2O)2−] in the A336/[P2225][TFSA] system.