(747c) A Scalable Method for Producing Graphene Membranes with Nanofiltration Properties

We have developed a novel and mass-producible method for fabricating supported Graphene-based membranes. Rheologically-tailored Graphene Oxide (GO) dispersions are cast on microfiltration Nylon (pore size ~ 0.2 µm) support membrane by knife coating – a very simple and rapid method to produce ~10 cm×15 cm membranes in less than a minute. Scanning electron and polarized light microscopy reveal well-packed and ordered structure. The microstructure can be tuned by shear rate and rheological characteristics of the coating fluid. Preliminary filtration studies have shown large water flux (25 litres/m²-hour-bar) and 100% rejection of Direct Yellow 50 (956.82  g/mol), > 99% for Methylene blue (319.85 g/mol), > 92% for Rhodamine B (479.02), ~ 86% for Methyl Viologen (257.16 g/ mol) indicating the suitability as a novel nanofiltration membrane. Rejection mechanisms are reliant on physical sieving and electrostatic interactions with minimal adsorption. This new process of ideal asymmetric membranes on macroporous supports is scalable and has the potential to be translated to large areas easily.