Efficient Reverse Osmosis-Based Desalination Using Functionalized Graphene Oxide Nanopores

In this work, based upon molecular dynamics (MD) simulations, two kinds of nanopores with different pore sizes and functions were constructed to study the directional transport of water molecules. The results showed that the functional groups at the edges of pores had a significant effect on water flux. Moreover, COH (hydroxyl) and CH (hydrogen) modified by graphene oxide (GO) nanopores had good water permeability. However, for small pore sizes, the flux from hydrophilic GO-COH was smaller than that from hydrophobic GO-CH. For large pore sizes, the hydrophilic functional group's water flux was nearly 24% higher than that of the hydrophobic functional group. To further explore the effect of hydrophilic functional groups on the flux of water flux, two functional groups of COOH (carboxyl group) and COO− (ionized carboxyl group) were constructed to modify the graphene nanopores. Due to the solid molecular affinity between water and GO-COO− surface, the water flux of GO-COO− was much higher than that of GO-COOH. The GO-COO− hole showed selective penetration of water. The results prove that the hydrophilic COO− on GO sheet can improve the permeability of water molecules.