Preparation of ultra-thin poly(vinyl alcohol) membranes supported on polysulfone hollow fiber and their application for production of pure water from seawater

Abstract

Pervaporation membrane process using polymeric membrane is promising for production of high-quality water from seawater. The use of membrane support is necessary for improvements in the membrane performance. In this work, preparation of thin poly(vinyl alcohol) (PVA) membranes over polysulfone hollow fiber support and their application for production of pure water from seawater through pervaporation separation process is reported. The uniformly thin PVA membrane coating over the cylindrical hollow fiber support of about 1.10mm diameter was obtained by an automatic dip-coating method. The coating solution was a dilute aqueous solution of PVA (61,000g/mol, molecular weight) and maleic acid having a molar composition in the range of 1 C2H4O (vinyl alcohol): 0.05–0.20 C4H4O4 (maleic acid): 61–815 H2O. The conductance of produced water by the membranes from desalination of saline water of 30,000ppm NaCl concentration was in the conductance range of pure water grade. The thinnest coated membrane exhibited permeate flux of about 7.4L/m2/h from the feed water of 30,000ppm NaCl at 344K. The apparent activation energy of the pervaporation desalination based on the volume flux of the membranes was determined as about 23.1–25.8kJ/mol.