Researchers from China's Xiamen University and Hangzhou Dianzi University, working with Wageningen University & Research in the Netherlands, have developed graphene-based woven filter membrane with excellent strength and efficiency for water desalination.
Their development resulted in an efficient water filtering method using these graphene-based woven filter membrane (GWFM), leading to an improvement of water permeation and mechanical properties by the optimization of GWFM membrane and providing a new way to utilize nano-woven membranes for desalination.
Properties like water flux, flow rate, salt rejection and mechanical properties of the GWFMs were calculated by molecular dynamics (MD) simulations. Two nanopore size of GWFMs were designed, namely 0.8 nm and 0.6 nm. The tensile strength of GWFM-0.6nm and GWFM-0.8nm were 48.87 GPa and 42.29 GPa, with water flux as high as 18.53 ± 0.99 L cm−2 day−1 MPa−1 and 39.22 ± 2.50 L cm−2 day−1 MPa−1, which are three orders of magnitude higher than existing commercial reverse osmosis membranes in water flux.
The free energy profiles of H2O and ions passing through GWFMs showed that the free energy barrier difference between water molecules and Na+/Cl− can reach ~35 kBT (GWFM-0.6nm), guaranteeing almost 100% desalination efficiency at constant pressure from 10 MPa to 500 MPa during simulation time.
The team's results provide a general framework to design desalination membranes with high water flux and high tensile strength using a nano-woven approach.