TUBULAR INTERPOLYMER ION-EXCHANGE MEMBRANES - DONNAN DIALYSIS THROUGH STRONG-BASE MEMBRANES

Strong-base tubular membranes prepared from the system polyethylene/poly (styrene-co-divinylbenzene)[PE/poly(St-co-DVB)] were tested in a Donnan dialysis process. The membranes had various amounts of DVB-0.5, 2 and 10 wt.%-in the aromatic component of the polymeric material and various types of functional groups-trimethylamine (TMA), triethylamine (TEA), dimethylaminoethanol (DMAE) and diethylaminoethanol (DEAE). Transport properties of the membranes were examined in the system 0.01 M HCl |membrane| 1 M NaOH to determine the OH- ion interdiffusion coefficient, rate of dialysate deacidification and flux of Na+ ions in the temperature range 25-55°C. It was found that the efficiency of Donnan dialysis depended on the type and molar concentration of functional groups and on the DVB content. The best results, i.e., reasonable rate of dialysate deacidification with low co-ion flux from concentrated to dilute solution, were obtained at 35°C for the membrane with TMA groups and 2% of DVB. © 1990.