Abstract
An acid extractant, di (2, 4, 4-trimethylpentyl) phosphinic acid (Cyanex 272), was impregnated to the hydrophobic ligand of a polymer chain grafted onto the pore surface of a porous membrane of a hollow-fiber form. The hydrophobic ligand was introduced by a reaction of an epoxy group of the poly-glycidyl methacrylate, which was appended to the porous membrane by radiation-induced graft polymerization, with n-alkylamine (CnH2n+1NH2) or n-octadecanethiol (C18H37SH). The carbon number of the n-alkylamino group ranged from 0 to 18. The amount of Cyanex 272 impregnated onto the porous membrane increased with an increasing density of the n-octadecylamino group, whereas the amount of impregnated Cyanex 272 was constant irrespective of the density of the n-octadecanethiol group. No leakage of Cyanex 272 impregnated to the n-dodecylamino or n-octadecylamino group of the graft chain was observed. The capturing of zinc ions by the Cyanex 272-impregnated porous hollow-fiber membrane was achieved during the permeation of a zinc chloride solution through the pores of the porous membrane. The equilibrium binding capacity of the Cyanex 272-impregnated porous hollow-fiber membrane for zinc ions was 0.37 mol/kg of the GMA-grafted membrane.
