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

• Published in: Angewandte Chemie International Edition 2023-06, Vol.62 (23), p.e202302931-n/a
• Main Authors: Guo, Jing, Zhang, Yanqiu, Yang, Fan, Mamba, Bhekie B., Ma, Jun, Shao, Lu, Liu, Shaomin
• Format: Article
• Language: English
• Subjects: Chemical synthesis; Graphene; Membranes; Metal ions; Polyamide resins; Polyamides; Positively Charged Surface; Water scarcity; Water Treatment; “Posterior” Interfacial Polymerization
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202302931

Two‐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. A “posterior” interfacial polymerization (p‐IP) strategy is developed to fabricate a graphene oxide (GO) framework membrane with a highly positively charged surface for ion sieving. The generated electrostatic repulsion of ions from the positively charged surface, in conjunction with reinforced size exclusion from the p‐IP‐formed polyamide network, endows the membrane with outstanding performance for ion separation.