Progress and prospects of two-dimensional materials for membrane-based water desalination

Water scarcity is one of the most critical issues of this century. Currently, water desalination is performed using polymeric membranes. However, the polymers suffer from low water permeability and degradation, both of which increase energy consumption and the cost of water desalination. There have been several breakthroughs by deploying two-dimensional (2D) materials with the merits of excellent water permeability and chemical resistance, rendering them highly promising as alternative materials of choice for water desalination. However, controlling and maintaining the pores and channels of 2D-based membranes down to the subnanometer level is a challenging process. Herein, we summarized the research progress on 2D materials for membrane-based water desalination. Several nanoporous and stacked membranes of 2D materials are discussed. Design strategies to maintain the stability of the membranes are particularly elucidated, including pore size optimization and interlayer spacing engineering down to subnanometer scales. The current challenges and future research directions are also presented. (C) 2020 The Authors. Published by Elsevier Ltd.