Constructing multi-path channels in graphene oxide-based membrane for high-efficiency oil/water separation

Abstract

Graphene oxide (GO) membranes have demonstrated significant potential for effective wastewater treatment; however, their tortuous and irregular water transport pathways through stacked nanosheets pose considerable challenges. In this study, we present a novel approach for fabricating faveolate-structured graphene oxide nanomesh (GONM) membranes, enhanced by the in situ growth of Co(OH)2 nanosheets to facilitate oil–water separation. The incorporation of in-plane pathways through the porous GONM, alongside the enlargement of interlayer pathways from Co(OH)2 growth, significantly improves water permeance. The nanopores present in the holey GONM reduce diffusion pathways, while intercalation of Co(OH)2 nanosheets increases channel sizes and stabilizes the GONM structure. By manipulating the mass ratio between GONM and cobalt salt, we optimized the membrane, achieving an exceptional water permeance of 224.2 L m-2h−1 bar−1, surpassing GO membranes. Additionally, the resultant membranes exhibit remarkable underwater anti-oil adhesion performance and efficient separation capabilities for a wide variety of oil-in-water emulsions, with separation efficiencies exceeding 99.1 %. This work provides valuable insights into the intentional manipulation of surface topography and hierarchical nanochannels in membrane materials, paving the way for high-efficiency water treatment solutions.