METAL COLLECTION USING CHELATING HOLLOW FIBER MEMBRANE

Three kinds of functional groups, iminodiacetate (IDA), amidoxime (AO), and phosphoric acid (PA), were introduced into a microfiltration hollow fiber membrane by radiation-induced grafting and subsequent chemical modification. The chelating hollow fibers containing AO or IDA groups exhibited a 1.1 m3/(m2-hr) pure water flux at 100% grafting of each precursor monomer, while the hollow fiber containing the PA group had a negligible flux. Breakthrough curves were obtained by permeating a metal-ion-containing feed solution radially from inside to outside of the chelating hollow fiber. The IDA chelating hollow fiber was superior to the AO chelating hollow fiber with regard to the collection of cobalt ion. The IDA hollow fiber, whose degree of glycidyl methacrylate grafting ranged from 20 to 260%, had a saturation capacity of cobalt ion of 0.13-1.3 mole Co per kg of base polymer.