Novel self-supported natural and synthetic polymer membranes for air humidification

Abstract

Novel self-supported natural and synthetic polymer membranes of chitosan-hydroxy ethyl cellulose-montmorillonite (CS-HEC-MMT) and polyvinyl alcohol (PVA)-polystyrene sulfonic acid (PSSA) are prepared by solution casting method followed by crosslinking. These membranes are employed for air humidification at varying temperatures between 30° C and 70° C and their performances are compared with commercial Nafion^® membranes. High water fluxes with desired humidified-air output have been achieved for CS-HEC-MMT and PVA-PSSA hybrid membranes at air-flow rates of 1-10 slpm. Variation in the air/water mixing ratio, dew point, and relative humidity that ultimately results in desired water flux with respect to air-flow rates are also quantified for all the membranes. Water flux values for CS-HEC-MMT are less than those for Nafion^® and PVA-PSSA membranes, but the operational stability of CS-HEC-MMT membrane is higher than PVA-PSSA and comparable with Nafion^® both of which can operate up to 70° C at repetitive cycles of humidification.