Hollow fiber type cation-exchange (C-HF) membranes and hollow fiber type anion-exchange (A-HF) membranes were prepared from poly (vinyl alcohol) (PVA)-based copolymer with cation-exchange groups and by blending PVA and polycation, respectively, by a gel fiber spinning method. In order to control the water content of the hollow fiber membranes, the membranes were cross-linked physically by annealing, and then cross-linked chemically by using glutaraldehyde (GA) solutions at various GA concentrations. The outer diameter of C-HF and A-HF membranes were ca. 1000 μm and ca. 1500 μm, respectively, and the thickness of the membranes were ca. 170 μm and 290 μm, respectively. Permeation experiments were carried out in two Donnan dialysis systems, which included mixed 0.1 M NaCl and 0.1 M CaCl2/C-HF /3 × 10−4 M CaCl2 and mixed 0.1 M NaCl and 0.1 M NaNO3/A-HF/3 × 10−4 M NaNO3 to examine ionic perm selectivity of the membranes. In the Donnan dialysis experiments using C-HF membranes, uphill transport of the divalent cations occurred, and, in the case of A-HF membranes, uphill transport of NO3− ions occurred. C-HF and A-HF membranes had about half of the flux in the uphill transported ions and also about half of the selectivity between the uphill transport ions and driven ions in comparison with those of the commercial flat sheet cation-exchange membrane (Neosepta® CMX) and anion-exchange membrane (Neosepta® AMX). Yet, IEC of C-HF and A-HF membranes were about one fifth of CMX and less than half of AMX, respectively. Since hollow fiber membrane module will have higher packing density than a flat membrane stack, the hollow fiber type ion-exchange membranes (IEMs) prepared in this study will have a potential application to a Donnan dialysis process.

Hydrophilic hollow fiber membranes were prepared from a aqueous solution of poly(vinyl alcohol) (PVA) by a gel fiber spinning method. In order to control the water content of the hollow fiber membranes, the membranes were cross-linked physically by annealing, and then crosslinked chemically using glutaraldehyde (GA) solutions changing GA concentration. The diameter of the membranes was ca. 1.0 mm and the thickness of the membranes was ca. 100 mm. Permeation experiments were carried out in a diffusion dialysis system: NaNO 3 solution/membrane/mixed NaNO 3 and NaCl solution to examine ionic permselectivity of the membranes. The flux of both nitrate ions and chloride ions through the membranes decreases with increasing GA concentration. This is due to the fact that membrane water content decreases with increasing GA content. The selectivity coefficient for nitrate ions through the membranes increases with GA content because of the decreasing in the water content. The hollow fiber membrane prepared in this study will have potential application to separation of trace ions in ground water.