Simulations of Tapered Channel in Multilayer Graphene as Reverse Osmosis Membrane for Desalination

Pressure-driven reverse osmosis membrane has important application in seawater desalination. Inspired by the structure of aquaporin, we established and studied the mechanism of the structure of multilayer graphene with tapered channels as reverse osmosis. The water flux of multilayer graphene with tapered channels was about 20% higher than that of parallel graphene channel. The flow resistance model was established, and the relationship between flow resistance and opening angles was clarified. The relationship between flow resistance and outlet size was also described. By means of molecular dynamics simulation, slip coefficients of multilayer graphene with tapered channel were obtained and verified by the contact angle of water. Results show that the permeability of graphene with tapered channel is about three orders of magnitude higher than that of commercial reverse osmosis membrane and the desalination rate is 100%. Temperature difference between the two sides of the tapered channel will promote the water flux positively.