Polydimethyl siloxane–graphene nanosheets hybrid membranes with enhanced pervaporative desulfurization performance

Abstract

A series of polydimethyl siloxane-graphene nanosheets (PDMS-GNS) hybrid membranes were fabricated via physically blending method. In these hybrid membranes, GNS exhibit different orientation and dispersity with the variation of GNS content. An appropriate interfacial structure favoring permeate molecules transport is constructed, which mainly arises from the non-covalent interactions between PDMS and GNS. The mechanical stability, thermal stability and anti-swelling property of the hybrid membranes are simultaneously enhanced. Pervaporative desulfurization performance of PDMS-GNS/PVDE hybrid membranes was investigated utilizing n-octane/thiophene mixture as a model gasoline system. The prepared hybrid membranes show an enhanced permeation flux while maintaining a constant enrichment factor, which should be attributed to the optimized free volume characteristics of the membranes and pi-pi interactions between GNS and thiophene. Especially, when GNS/PDMS mass ratio reaches 0.2 wt%, the membrane shows an optimum desulfurization performance with a permeation flux of 622 kg/(m(2) h) (65.9% higher than that of pure PDMS membrane) and an enrichment factor of 3.58 (similar to that of pure PDMS membrane). Additionally, the effects of GNS content, operation temperature, thiophene content, feed Row rate and operation time on membrane separation performance were investigated systematically. The prepared hybrid membranes may find potential applications in the separation of aromatics-containing mixtures. (C) 2015 Elsevier B.V. All rights reserved.