Graphene oxide modified membrane for highly efficient wastewater treatment by dynamic combination of nanofiltration and catalysis.

Stacked graphene oxide (GO) nano-sheets with plentiful nanopores incorporated onto polymeric membrane are promising for water purification. However, maintaining high water permeability without sacrificing separation efficiency remains a challenge. Delamination of the GO layer from the membrane surface is another bottleneck affecting the efficiency of the material. To solve those problems, we immobilized a chemically crosslinked GO composite layer with enlarged interlayer space on the surface of a novel catalytic membrane, which served as the support. The modified GO nanosheets-coated catalytic membranes showed excellent separation robustness with withstanding strong lateral shear force during 6 h filtration in a crossflow model. The as-prepared membrane showed high removal efficiencies to Congo red and Basic blue (99 % and 96 %, respectively) due to the surface-coated GO composite layer. Furthermore, while launching the catalytic function of the membrane with a trace amount of reducing agent (NaBH4), the GO-coated composite membrane successfully purified 50 ppm Methyl orange, 50 ppm Methylene blue, 50 ppm Rhodamine B and 0.272 mmol/L 4-Nitrophenol to break through the membrane rejection limitation of 500 Mw. Combining nano-filtration and catalysis, the GO-coated composite membranes showed great potential for the continuous purification of chemically contaminated water.