HYDROPHILIC HOLLOW-FIBER MEMBRANES FOR WATER DESALINATION BY THE PERVAPORATION METHOD

Hydrophilic ion-exchange membranes based on sulfonated polyethylene ho llow fibers were manufactured, and their suitability for a water perva poration process was studied for possible application in water desalin ation systems. The effects of the following parameters on the average water flux were determined: membrane properties (diameter (0.4-1.8 mm) and wall thickness (0.05-0.18 mm)); charge density (0.6-1.2 meq g(-1) ); and operating conditions (brine inlet temperature (30-68 degrees C) , air sweep velocity (0-6 m s(-1)), and salt concentration in the feed brine (0-3 M)). A water flux of 0.8-3.3 kg m(-2) h(-1) was obtained u sing this type of hollow fiber with an inlet brine temperature of 25-6 5 degrees C. It was found that, for our application, the optimal speci fications for the ion-exchange hollow fibers were an outside diameter of 1.2 mm, a wall thickness of 0.1 mm, and an ion-charge density of ab out 1.0 meq g(-1). This information is required as basic data for the design of a prototype water desalination system based on a pervaporati on system that uses this type of ion-exchange hollow fiber membrane.