(340r) Design and Studies of CVD Graphene-Based Membranes on Modified Support for Water Treatment Applications

Freshwater is a primary concern for all the people around the world. So far, seawater desalination has been performed via membrane technologies.

One of the most important and recently studied candidates for use in Reverse Osmosis (RO) or nanofiltration (NF) membranes is graphene which has excellent chemical and mechanical stability. Graphene is the thinnest possible membrane with its one atom thickness acting as the membrane. Small thickness is desirable because it gives high flux. But high flux must be accompanied by high salt rejection. The application of plasma methods can make the graphene membrane and its substrate controllably nanoporous to give the desired high flux and high salt rejection. In a further benefit, graphene manifests greater resistance to chlorine than current polyamide membranes.

It is vital to have a flexible substrate (hydrogel) that can hold the one-atom-thick graphene membrane while still permitting quick water transmission for fabricating an effective graphene NF/RO membrane. The procedure of transferring CVD graphene on a hydrogel-modified NF membrane will be addressed in this study. If CVD graphene is directly put to a membrane support structure, it is weak and readily broken. A hydrogel underlayer—polyvinyl alcohol (PVA)—has been produced, cross-linked, and placed onto a membrane support to facilitate transmission without damage. The permeability of a PVA / support membrane is affected by the degree of crosslinking and the thickness of the PVA layer. To reduce the chance of defects forming, the graphene is deposited onto the PVA support using a simple yet innovative method. The graphene as RO membrane will be examined utilizing experimental work combined with membrane characterization tools (SEM, AFM, and FTIR) and filtering investigations using a home-made RO system. These findings will be compared to those of other membranes created and different types of supports.