A Facile and Scalable Method of Fabrication of Large-Area Ultrathin Graphene Oxide Nanofiltration Membrane

With their ultrafast water transport and excellent molecule sieving properties, graphene oxide (GO)-based membranes show great potential in the membrane filtration field for water purification and molecular separation. However, the inability of uniform GO membranes to be produced on an industrial scale and their nonenvironmentally friendly reduction treatment are the bottle-neck preventing their industrial applications. Herein, we report a scalable ultrathin uniform GO membrane fabrication technique. Ultrathin GO membranes with a large area of 30 x 80 cm(2) and a thickness of a few nanometers were uniformly and facilely fabricated using a continuous process combining Mayer rod-coating and a short-time, high-power UV reduction. The interlayer spacing of the GO membrane could be effectively reduced and regulated to improve the salt rejection rate. The fabricated membrane showed superior water permeability of over 60.0 kg m(-2) h(-1) and a high separation efficiency of over 96.0% for a sodium sulfate (Na2SO4) solution. It also exhibited excellent mechanical stability under various harsh crossflow conditions. More importantly, the fabrication method developed here can be scaled up using a roll-to-roll industrial production process, which successfully solves the problem currently faced by GO membrane researchers and makes the industrial usage of GO membrane a reality.

Automated summary

The scalable ultrathin uniform GO membrane fabrication technique reported in this study utilizes Mayer rod-coating and short-time, high-power UV reduction to produce large area, thin GO membranes. The interlayer spacing of the membrane can be effectively reduced and regulated to improve salt rejection rate, while the fabricated membrane shows superior water permeability and high separation efficiency, along with excellent mechanical stability under harsh conditions. The developed fabrication method can be scaled up using a roll-to-roll industrial production process, solving the current bottleneck in GO membrane research and enabling industrial usage of GO membrane.