Borate Inorganic Cross-Linked Durable Graphene Oxide Membrane Preparation and Membrane Fouling Control.

Graphene oxide (GO) membranes have the potential to be next-generation membranes. However, the GO layer easily swells in water and risks shedding during the long-term filtration. Organic GO interlayer organic cross-linking agent was not resistant to oxidation, which limits the application scope of GO membrane. In this study, an inorganic cross-linked GO membrane was prepared via the reaction of sodium tetraborate and GO hydroxyl groups, and a -B-O-C- cross-linking bond was detected by X-ray photoelectron spectroscopy (XPS). Additionally, a new atomic force microscope scratch method to evaluate the cross-linking force of a nanoscale GO layer was proposed. It showed that the critical destructive load of the inorganic cross-linked GO membrane increased from 8 to 80 nN, which was a 10-fold increase from that of the nonlinked sample. During the NaOH/sodium dodecyl sulfate (SDS) destructive wash tests, morphology, flux and retention rate of inorganic cross-linked GO remained stable while the comparative membranes showed significant destruction. At the same time, based on the better oxidation resistance, organic membrane fouling was effectively controlled by the introduction of trace ·OH radicals. This study provides a new perspective for GO membrane preparation, interlayer cross-linking force testing and membrane fouling control.