Ultrafast water evaporation through graphene membranes with subnanometer pores for desalination

XF Chen and YB Zhu and H Yu and JZ Liu and CD Easton and ZY Wang and YX Hu and ZL Xie and HA Wu and XW Zhang and D Li and HT Wang, JOURNAL OF MEMBRANE SCIENCE, 621, 118934 (2021).

DOI: 10.1016/j.memsci.2020.118934

Controlling the pore sizes of graphene-based membranes is essential for exploring their transport properties and related applications such as water desalination. We demonstrated the scalable fabrication of ultrathin graphene membranes with precisely controlled subnanometer pores by co-assembly of graphene oxide nanosheet and polymer on a porous ceramic substrate and subsequent reduction and carbonization. The resulting graphene membranes with an intercalated structure show unprecedented molecular-sieving water evaporation properties, achieving water evaporation flux of 49.8 +/- 1.5-472.3 +/- 14.2 L m(-2) h(-1) and 99.99% NaCl rejection at 20-70 degrees C and a vacuum of -800 mbar. The water flux is remarkably higher than that of conventional microporous membranes and greatly surpasses that of the state-of-the art membranes with various pore sizes. This work provides a new insight into water transport and evaporation through graphene subnanometer pores, and a new strategy for membrane design for water desalination and other evaporation separations.

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