Rational Design of Superhydrophobic and Flexible Oriented MOF Nanosheet Membrane for Highly Efficient Ethanol–Water Separation

Highly efficient and energy-conserving membrane separation technology holds vast potential for applications in the bioethanol production process. This work reports a strategy for the fast preparation of an oriented and flexible two-dimensional metal-organic framework (MOF) nanosheet membrane by an electrochemical deposition method. The oriented MOF nanosheet membrane growth, followed by spin-coating of polydimethylsiloxane, resulted in an efficiently formed superhydrophobic and ethanol affinity membrane for separating ethanol from aqueous solution. Vertically aligned MOF nanosheets with strong ethanol affinity and superhydrophobic membrane surfaces simultaneously promote the transport process, thus delivering a relatively high flux of 1.63 kg·m^-2·h^-1 and good separation factor of 14.89 in the pervaporation of 5 wt % ethanol aqueous solution. The oriented arrangement of MOF nanosheets combined with polydimethylsiloxane can significantly enhance the pervaporation selectivity and flux, creating a preferential pathway for the production of biofuel.