Mixed matrix membranes prepared from poly(vinyl alcohol) (PVA) incorporated with zeolite 4A-graft-poly(2-hydroxyethyl methacrylate) (zeolite-g-PHEMA) for the pervaporation dehydration of water–acetone mixtures

The mixed matrix membranes (MMMs) were prepared from the crosslinked PVA incorporated with the zeolite 4A-graft-PHEMA. The grafting on the zeolite was successfully undertaken via the silylation of vinyl-silane followed by graft polymerization of HEMA monomer. The swelling of the membranes in various concentrations of water–acetone mixtures revealed a decrease in the swelling degree as the zeolite loading was increased. Subsequently, the sorption experiment was performed with the results suggesting preferential sorption of water by the membranes. Moreover, the water sorption selectivity increased with the zeolite loading particularly for low water concentration of the liquid mixtures. The dehydration of water–acetone mixtures using the MMMs was investigated through pervaporation. It was found that both water permeance and selectivity increased with an increase of the zeolite loading. In addition, for the same zeolite loading, increasing the amount of grafted-PHEMA on the zeolite not only enhanced the zeolite–PVA interfacial adhesion but also created a water-selective layer surrounding the zeolite which promoted the water selectivity. Nevertheless a decline of the water selectivity was observed as the feed water concentration as well as feed temperature increased.

Research highlights▶ The successful grafting of PHEMA on the zeolite 4A was undertaken via the silylation of vinyl-silane followed by graft polymerization of HEMA monomer. ▶ Both water permeance and selectivity increased with an increase of the zeolite loading. ▶ Increasing the amount of grafted-PHEMA on the zeolite not only enhanced the zeolite–PVA interfacial adhesion but also created a water-selective layer surrounding the zeolite which promoted the water selectivity.