Separation of ethylene glycol-water mixtures with composite poly(vinyl alcohol)-polypropylene membranes

Abstract

Composite membranes consisting of a crosslinked poly(vinyl alcohol)(PVA) active layer on top of a porous polypropylene (PP) support were prepared with glutaraldehyde as a crosslinking reagent. The degree of crosslinking and the thickness of the active layer were determined with attenuated total reflection-Fourier transform infrared spectroscopy and scanning electron microscopy, respectively. The membranes were used in the pervaporation dehydration of ethylene glycol (EG)-water mixtures. The effects of the crosslinker content and operational conditions, including feed EG concentration and operating temperature, on the permeation flux and selectivity of the PVA-PP composite membranes were investigated. We observed that the dehydration of a 80 wt % EG mixture at temperature of 60°C, a feed flow rate of 1.5 L/min, and a vacuum pressure of 10 mmHg could be effectively performed, and a moderate permeation flux and a high separation factor were obtained, that is, 0.91 kg m-2 h-1 and 1021, respectively. © 2010 Wiley Periodicals, Inc.