Ultra‐Permeable Dual‐Mechanism‐Driven Graphene Oxide Framework Membranes for Precision Ion Separations

Abstract

AbstractTwo‐dimensional graphene oxide (GO) membranes are gaining popularity as a promising means to address global water scarcity. However, current GO membranes fail to sufficiently exclude angstrom‐sized ions from solution. Herein, a de novo “posterior” interfacial polymerization (p‐IP) strategy is reported to construct a tailor‐made polyamide (PA) network in situ in an ultrathin GO membrane to strengthen size exclusion while imparting a positively charged membrane surface to repel metal ions. The electrostatic repulsion toward metal ions, coupled with the reinforced size exclusion, synergistically drives the high‐efficiency metal ion separation through the synthesized positively charged GO framework (PC‐GOF) membrane. This dual‐mechanism‐driven PC‐GOF membrane exhibits superior metal ion rejection, anti‐fouling ability, good operational stability, and ultra‐high permeance (five times that of pristine GO membranes), enabling a sound step towards a sustainable water‐energy‐food nexus.