Bio-inspired graphene oxide-amino acid cross-linked framework membrane trigger high water permeance and high metal ions rejection

As increasing demand for wastewater treatment, membranes with excellent performance are still needed in recent years. Graphene-based membranes are promising candidates by virtue of their outstanding mechanical properties, chemically resistant and atomic thickness. In this work, a kind of membrane with nacre-like structure of the hydrothermal reduction graphene oxide (hrGO) cross-linked by amino acid were fabricated. The hrGOamino acid membranes exhibited both high water permeance and high metal ions rejection. Typically, when treated FeCl3 solutions, the hrGO membrane cross-linked by tryptophan (Trp) represented 191.0 L m-2 h-1 bar- 1 water permeance which is 4.4-fold higher than that of pristine GO membrane, and is superior to other NF membranes while still maintained at 98.2% FeCl3 rejection. Moreover, the hrGO-Trp membrane also exhibited a stable separation performance in a long time. Overall, our work reveals a facile method to realize ultrahigh water permeance of GO-based membranes for wastewater treatment.