Economical salt resistance superhydrophobic photothermal membrane for highly efficient and stable solar desalination.

Recently, solar-driven interfacial water evaporation has shown great potential in desalination. In the practical application, the inevitable pollution and the accumulation of salt making the evaporation efficiency cannot be maintained for a long time. Herein, we reported a flexible and economical superhydrophobic photothermal membrane composed of polyvinyl pyrrolidone (PVP) and carbon nanotubes (CNTs) with 1H,1H,2H,2H-Perfluorodecyl triethoxysilane modification, and a piece of expanded polystyrene was used for support and thermal insulation. The prepared floating evaporation device shows a high energy efficiency of 91.1% and evaporation rate of 1.41 kg m-2 h-1 under one solar irradiation, and neither salt accumulation nor significant decrease in evaporation rate of the device was observed after either continuous operate for 40 h or 18 evaporation cycles. In addition, the self-cleaning performance of the membrane enables its surface to maintain high absorbance for a long time. With the stable and efficient evaporation performance of this device, it provided guidance for the application of efficient and long-term stable solar desalination.