Cell Membrane-Inspired Graphene Nanomesh Membrane for Fast Separation of Oil-in-Water Emulsions

摘要

Graphene exhibits fascinating prospects for preparing high-performancemembranes with fast water transport, due to its low friction with water andextreme thinness. However, for graphene-assembled membranes, eachmolecule passing through the membrane should bypass many graphenesheets, which lengthens the molecular pathways and increases the masstransfer resistance. Herein, a graphene nanomesh (GNM) membrane isfabricated that is inspired by cell membranes, including aquaporins withtheir hydrophilic gate for selective transport and hydrophobic channel forlow friction with water, thus resulting in fast water transport, as well ashydrophilic polymer brushes on the membrane surface for fouling resistance.GNM is synthesized by etching nanopores on graphene oxide (GO)nanosheets to significantly shorten the water transport channels, whereasthe hydrophobic graphene sheets lead to low water friction; in combination,ultra-fast, selective water flux is achieved. Also, hydrophilic polymer chitosanis utilized to modify GNM to construct a hydration layer, which suppressesfoulants from touching the membrane surface. Accordingly, the permeance ofthe cell membrane-inspired graphene nanomesh membrane reaches almost4000 L m~(–2) h~(–1) bar~(–1), which is about 260 times the permeance in a GO membrane,and the membranes show superior antifouling properties for separatingvarious surfactant-stabilized oil-in-water emulsions.