Selective electrorefining with liquid membranes

Abstract

Liquid membranes containing macrocyclic polyethers can be used to electrorefine metals. This purification depends on the selective reaction of the polyether and the metal cation to produce a charged product. The amount of this product is found to be proportional to the square root of the amount of polyester present. Results for silver and copper purification illustrate the ideas involved.

Electro‐membrane reactor: A powerful tool for green chemical engineering

“…The stacked ion‐exchange membrane between the two working electrodes increases throughput and improves the efficiency of the system. Ions are only transported across the membrane and no Faraday reaction occurs at the electrode to form H + /OH − ions, and the product is only generated in the chamber between the membranes and does not appear in the chambers on either side near the electrodes; (2) Electro‐membrane reactors based on Faraday reactions on electrodes, where ion‐exchange membranes are used for electric cycles and in‐situ product separation: Examples include CO 2 electrochemical reduction, 14 H 2 production through water electrolysis, 15,16 and membrane refining in the metallurgical industry 17 and chlor‐alkali industries. The product is only generated in the chambers on both sides near the electrodes, not in the chambers between the membranes 18 ; (3) Coupling of Faraday reactions on electrodes and stacked ion‐exchange membranes to efficiently separate the products or energy‐powering mass flux (coupled electro‐membrane reactor): Some examples are the electro‐electrodialysis for LiOH production and reverse electro‐electrodialysis for H 2 production 19,20 .…”