抄録
A basic extractant Aliquat 336 dissolved in a mixture of water and ethanol was impregnated to carboxypentyl-amino (CPA)-group-containing polymer chains grafted onto a porous hollow-fiber membrane. The CPA group was introduced into the graft chain by a reaction of the epoxy group of poly-glycidyl methacrylate (GMA) chain grafted onto the porous hollow-fiber membrane with 6-aminohexanoic acid. The electrostatic interaction between the carboxyl moiety of the CPA group and the quarternary ammonium group of Aliquat 336 gave rise to a high-density impregnation of Aliquat 336. A higher water volume fraction in the mixture of water and ethanol used as a solvent of Aliquat 336 induced a higher extension of the graft chain, resulting in an increase in the amount of Aliquat 336 impregnated. In addition, a higher Aliquat 336 concentration produced a higher amount of Aliquat 336 impregnated. A water volume fraction of 0.33 and an Aliquat 336 concentration of 10% were selected on the basis of a trade-off between the amount of Aliquat 336 impregnated and the liquid permeability. The pure water flux of porous hollow-fiber membrane with 1.2 mol Aliquat 336 per kg GMA-grafted porous hollow-fiber membrane was 2.5 m/h at 0.1 MPa and 298 K. During the permeation of 100 mg-Pt/L platinum chloride solution (pH 4.0) through the pores of the Aliquat 336- impregnated porous hollow-fiber membrane, platinum complex ions (PtCl6 2–) were captured by Aliquat 336 impregnated to the graft chain, while the permeation pressure required for a constant flow rate increased. The breakthrough binding capacity of the Aliquat 336-impregnated porous hollow-fiber membrane for platinum was 0.37 mol per kg of the GMA-grafted porous hollow-fiber membrane.
