METHOD FOR CONTROLLING CHANGE OF VALENCE OF METAL ION

摘要

PURPOSE:To efficiently control a change of the valence of metal ions producing plural kinds of oxidized state by dividing a cell into anode ad cathode chambers with a specified anion exchange membrane contg. fluorine and by oxidizing or reducing an aqueous soln. contg. the metal ions. CONSTITUTION:A cell is divided into anode-and cathode-chambers with an anion exchange membrane contg. fluorine made of a copolymer having repeating units represented by formula I (where X is F or CF3, l is 0 or an integer of 1-5, m is 0 or 1, n is an integer of 1-5, each of p and q is a positive number, p/q=2-16 and Y is a quat. ammonium group). The thickness of the anion exchange membrane is about 40-500mum, a reinforcing agent can be introduced into the membrane, and a group contg. the quat. ammonium group Y is represented by formula II (where each of R1-R3 is lower alkyl, R1 and R2 may bond to each other to form a tetra-or pentamethylene ring and Z- is a halogen anion). Metal ions producing plural kinds of oxidized state are fed to the electrode chambers and electrochemical oxidation or reduction id carried out.