Multifunctional integrated sandwich-structured evaporator based on nanofibrous membrane for efficient photothermal seawater desalination

Solar steam generation has gained considerable amount of attention due to its popularity in recent studies around seawater desalination. Herein, we suggest a sandwich-structured nanofibrous membrane that excels at highly efficient seawater evaporation desalination. The top thin layer made with MXene (Ti3C2Tx) to improve membrane's photothermal conversion efficiency. The highly hydrophobic electrospun Poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) fibers in the middle allow membrane to self-float on the seawater. Its highly interconnected nanofiber network structure provides an ideal environment for the transport of water vapors. The hydrophilic bottom layer is prepared by depositing cross-linked polydopamine and polyethyleneimine (PDA/PEI) on the PVDF-HFP fibers surface, which is designed to be in direct contact with seawater. Under three sun (3 kW m−2), the solar thermal conversion efficiency and evaporation rate of the membrane could reach 95.45% and 3.782 kg m−2 h−1. This multifunctional integrated sandwich-structured evaporator based on nanofibrous membrane provides a new strategy for water purification.