Fabrication of a Desalination Membrane with Enhanced Microbial Resistance through Vertical Alignment of Graphene Oxide

Biofouling is a major obstacle for the efficient and reliable operation of membrane-based desalination processes. Innovations in membrane materials and fabrication processes are therefore needed to develop antibiofouling strategies. In this study, we utilize the alignability of an emerging two-dimensional nanomaterial, graphene oxide (GO), to fabricate a desalination membrane with enhanced bacterial resistance. GO nanosheets are dispersed in a polymer solution to form a homogeneous mixture, which undergoes slow solvent evaporation in a magnetic field to create a thin nanocomposite membrane with vertically aligned GO nanosheets. The structural characteristics of the fabricated membranes confirm the enhanced exposure of nanosheet edges on the surface through the vertical alignment of GO. Notably, the addition and alignment of GO do not compromise membrane water permeability and water–salt selectivity. When contacted with bacterial cells, membranes with vertically aligned GO nanosheets exhibit enhanced antimicrobial activity compared with that of the non-aligned GO membrane. We attribute the enhanced antimicrobial activity to the maximization of edge-mediated interactions through vertical alignment of GO nanosheets. Our results suggest the potential of this membrane to delay the onset of biofouling in desalination and the promise of the developed platform for the design of antimicrobial surfaces for a variety of environmental applications.