Graphene Oxide Nanofiltration Membranes Stabilized by Cationic Porphyrin for High Salt Rejection.

Swelling has great influences on the structure stability and separation performance of graphene oxide laminate membranes (GOLMs) for water desalination and purification. Herein, we report cross-linked GOLMs from GO assembled with cationic tetrakis(1-methyl-pyridinium-4-yl)porphyrin (TMPyP) by a vacuum-assisted strategy. The concave nonoxide regions (G regions) of GO are used as cross-linking sites for the first time to precisely control the channel size for water permeation and salt ion retention. Channels around 1 nm are constructed by modulating the assembly ratio of TMPyP/GO, and these cross-linked GOLMs show high salt rejection.