Extraction of rhodium by liquid surfactant membranes containing ionic liquid as a carrier from hydrochloric acid solutions

Extraction behavior of rhodium (III) with a liquid surfactant membrane (LSM) containing an ionic liquid, 1-octyl-3-me-thylimidazolium hexafluorophosphate ([Omim][PF₆]), as a carrier from hydrochloric acid solutions has been investigated. At the optimum conditions, rhodium was selectively extracted over tin by using LSMs in which [Omim][PF₆] acted as the mobile carrier. The effects of important operational parameters on the recovery of rhodium were examined with three different stripping reagents for LSMs. It was found that the use of 2-amino-2- hydroxymethyl-1,3-propanediol (Tris) as a stripping reagent in LSMs was the key for the effective extraction of rhodium.