Highly flexible and superhydrophobic MOF nanosheet membrane for ultrafast alcohol-water separation.

Xu, Li-Hao; Li, Shen-Hui; Mao, Heng; Li, Yan; Zhang, Ao-Shuai; Wang, Sen; Liu, Wei-Min; Lv, Jing et al. · Science · 2022

basic_science · Level V

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Abstract

High-performance pervaporation membranes have potential in industrial separation applications, but overcoming the permeability-selectivity trade-off is a challenge. We report a strategy to create highly flexible metal-organic framework nanosheet (MOF-NS) membranes with a faveolate structure on polymer substrates for alcohol-water separation. The controlled growth followed by a surface-coating method effectively produced flexible and defect-free superhydrophobic MOF-NS membranes. The reversible deformation of the flexible MOF-NS and the vertical interlamellar pathways were captured with electron microscopy. Molecular simulations confirmed the structure and revealed transport mechanism. The ultrafast transport channels in MOF-NS exhibited an ultrahigh flux and a separation factor of 8.9 in the pervaporation of 5 weight % ethanol-water at 40°C, which can be used for biofuel recovery. MOF-NS and polydimethylsiloxane synergistically contribute to the separation performance.