Scalable and low-cost fabrication of hydrophobic PVDF/WS2 porous membrane for highly efficient solar steam generation.

ABSTRACT

Solar steam generation based on the light-to-heat conversion via photothermal materials has been considered as one of emerged technologies for utilizing solar energy to produce clean water. Here, a hydrophobic PVDF/WS2 porous membrane for highly efficient solar steam generation was prepared by a scalable and low-cost method. The WS2 photothermal materials were fabricated through a simple ball milling, and then a non-solvent induced phase inversion method was used to fabricate the porous PVDF/WS2 membrane. The PVDF/WS2 evaporator could absorb the sunlight of 90.58% from UV to NIR region due to the multiscattering of the porous structure and the synergistic effect of WS2 and seawater. Moreover, the PVDF/WS2 evaporator exhibits the hydrophobic properties. Taking the advantages mentioned above, our evaporator could manifest the evaporation rate of 4.15 kgm-2h-1 with the solar thermal efficiency of 94.2% under 3 sun irradiation, as well as an outstanding durability upon continuous running. Also, the evaporator shows both the excellent seawater desalination and sewage treatment ability. Outdoor experiments illustrate that the evaporator has practical applications under a natural sunlight condition. The numerous advantages of our PVDF/WS2 evaporator, including the high solar-thermal efficiency, the outstanding durability, and the simple and scalable manufacture process, may provide a potential photothermal material for the commercial solar desalination application and wastewater treatment.