Recyclable solar evaporator based on hollow glass microspheres for water purification and desalination

Solar-driven interfacial steam generation (SISG) has attracted much more attention for its significant potential in water purification and desalination. Herein, we report the fabrication of a novel photothermal material (MHGM/ Fe3O4/TiO2-Ag/PPy) by coating Fe3O4, TiO2 & Ag, and fluorosilane doped polypyrrole (PPy) on (3-Amino-propyl)triethoxysilane modified hollow glass microspheres (MHGM), respectively, and a certain amount of such hollow microspheres self-float on the water surface as a solar evaporator for efficient SISG. Benefiting from low thermal conductivity (0.0455 W m(-1) k(-1)), strong light absorption (about 95%) and the gap between the microspheres provides the channels for water transportation, the as-prepared solar evaporator of MHGM/Fe3O4/TiO2-Ag/PPy shows a high water evaporation rate of 1.5516 kg m(-2) h(-1) under 1 kW m(-2) solar irradiation. Moreover, the evaporator with unique spherical hollow structure exhibits excellent salt resistance, as well as efficient water purification and antibacterial performance. More importantly, the evaporator possesses magnetic property and can be magnetically recovered. Thus, the as-prepared solar evaporator shows great potential for practical applications, including seawater desalination, sterilization and synergistic water purification during freshwater production.

Automated summary

In this study, a novel photothermal material was fabricated and a highly efficient solar evaporator was successfully prepared. The evaporator exhibits low thermal conductivity, strong light absorption, and a unique spherical hollow structure, resulting in a high water evaporation rate, excellent salt resistance, antibacterial performance, and magnetic recoverability.