anion-exchange groups were introduced into an existing microfiltration membrane by radiation-induced grafting and subsequent chemical modification. the tertiary-amino-group-containing monomers, i.e. diethylaminoethyl methacrylate (deaema) and vinyl pyridine (vp), and epoxy-group-containing monomer, i.e, glycidyl methacrylate (gma), were grafted onto the porous polyethylene hollow-fiber membrane. the epoxy group produced in the gma-grafted hollow fiber was converted into tertiary amino groups by reaction with diethylamine (dea) and 4-aminopyridine (ap). subsequently, the dea-and ap-modified hollow fibers and the deaema- and vp-grafted hollow fibers were all quaternized with benzyl chloride (bc). measurements of pure water flux and ion-exchange capacity of the resulting membranes, which contained a strongly basic anion-exchange group, demonstrated that the quaternized membrane (dea-bc-t fiber) originating from the dea-modified membrane was the most suitable membrane for anion collection by permeation through its pores. the dea-bc-t fiber had a pure water flux of 1.0 m/hr at a filtration pressure of 0.1 mpa and an ion-exchange capacity of 1 mol/kg. (author abstract) 19 refs