Synthesis of Graphene Oxide Membranes Via Layer-By-Layer Assembly

Graphene oxide (GO) is a one-atom-thick oxygenated carbon lattice bearing many desirable properties that can be advantageously exploited to make water filtration membranes. These properties include fast water transport on graphene surface, excellent stackability, ample functional sites, high adsorption capacity, and low manufacturing cost. Unbonded GO nanosheets, however, lack stability in water environment and thus are not directly applicable as a water filtration membrane. In the present study, we employed a layer-by-layer approach to synthesize a new type of membrane with GO nanosheets, which were deposited on a polysulfone support with a specified number of layers and chemically cross-linked between adjacent layers using 1,3,5-benzenetricarbonyl trichloride.  Experimental results demonstrated that the synthesized GO membrane had relatively high water permeability (178±98 LMH/MPa) and high rejection (94±1%) of Rhodamine-WT.  It was also found that the cross-linking successfully provided stability to the membrane and in the meantime offered an opportunity to further adjust the charges, functionality, and spacing of the stacked GO nanosheets in the membrane. Indeed, the facile, scalable synthesis of GO membranes using the present method opens a new avenue for making a next-generation of high-performance, cost-effective membranes for sustainable water purification.