A novel surface cross-linked GO-based membrane with superior separation performance

In this study, a novel procedure of fabricating a high performance graphene oxide (GO) composite membrane with high water permeability and selectivity was developed. The GO-based composite membrane, which was fabricated by assembling GO nanosheets on a polyacrylonitrile (PAN) ultrafiltration substrate using vacuum filtration method, was cross-linked by 1,3,5-benzenetricarbonyl trichloride (TMC). Intriguingly, the cross-linking reaction that just occurred at the surface of the GO layer not only provides a stable spacing of the surface GO nanosheets, which ensures the separation accuracy of the composite membrane, but also keeps a high water transport efficiency when passing through the uncross-linked interlamination channels of the GO layer. Pervaporation performance testing, using a water/ethanol feed solution, demonstrated that the separation accuracy and water flux for the optimized surface cross-linked GO composite membrane (TGOm) were significantly better or at least comparable to the values from the GO composite membrane (GOm), and the separation factor of TGOm was enhanced almost several fold. Additionally, with the increasing temperature of the feed solution, the TGOm still maintained an “ideal” separation accuracy, indicating the fine thermostability of the cross-linked membrane.