Ionic crosslinking of SO3H-group-containing graft chains helps to capture lysozyme in a permeation mode

SO3H-groupcontaining polymer chains were grafted onto a porous hollow-fiber membrane uniformly across the thickness of the membrane (about 0.9 mm) by radiation-induced graft polymerization of glycidyl methacrylate and subsequent reaction with sodium sulfite. The graft chains extended from the pore surface due to their mutual electrostatic repulsion, and were crosslinked with bivalent ions such as Mg2+ and Ca2+, resulting in an increase in permeation rate of the liquid through the pores. Lysozyme was bound in multilayers to the SO3H-group-containing graft chains, which had been previously crosslinked with Mg ions, and the permeation rate was increased with the progression of lysozyme binding based on the ion-exchange interaction with Mg ions. (C) 1999 Elsevier Science B.V. All rights reserved.