| 摘要 |
PURPOSE:To efficiently and stably recover a metal from waste liquor by recovering the metal with an anion exchange membrane contg. fluorine obtd. by treating a specified carboxylic ester film. CONSTITUTION:A metal is recovered form waste liquor discharged from a plating plant with an anion exchange membrane contg. fluorine. The membrane is obtd. by treating one side or both sides of a carboxylic ester film made of a copolymer having repeating units represented by formula I with an acid such as hydrochloric acid or a base such as an aqueous ammonia soln. and by introducing anion exchange groups into the film. In the formula I, X is F or CF3, l is 0 or an integer of 1-5, m is 0 or an integer of 1-5, n is an integer of 1-5, p/q=4-16 and R is alkyl. The anion exchange groups are quat. ammonium groups 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 chain and Z<-> is a halogen anion, BF4<->, SbCl6<-> or the like).
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