Fabrication of a loose nanofiltration candidate from Polyacrylonitrile/Graphene oxide hybrid membrane via thermally induced phase separation

It is still a challenge to design and fabricate a robust nanoporous membrane in large scale and of fundamental importance for practical application. Here, a robust three/two-dimensional polyacrylonitrile/graphene oxide (PAN/GO) homogeneous nanoporous membrane is fabricated in large scale via thermally induced phase separation method, which guarantees the membrane with high mechanical strength and selective separation properties. Differing from conventional nanofiltration (NF) membrane with high rejection to both salt and dye, the resulting hybrid membrane is relative loose, which shows outstanding performances, i.e. high dye rejection and low salt rejection, high permeability and antifouling properties, acting as a promising candidate for dye/salt fractionation. The incorporation of 0.2 wt% GO endows membrane with excellent performance, where high tensile strength, high water permeability (33 L⋅ m−2⋅ h−1⋅ bar−1), selectivity (100% to methyl blue, 99.8% to acid red 18, 26.7% to magnesium sulfate and 10.9% to sodium chloride and flux recovery ratio of 84.4%) are perfectly balanced. Its homogeneous structure and high strength guarantee long term use without the peeling of thin active layer as encountered by conventional NF membranes. The successful fabrication of such a hybrid membrane provides an attractive opportunity for loose NF membrane preparation with performance enhancement in a feasible way for practical application.