High-salinity brine desalination and wastewater treatment strategies based on solar-driven interfacial evaporators

The increasingly severe water shortage and energy source scarcity have attracted global attention. Interfacial solar evaporation technology is a novel clean water acquisition technology that can utilize abundant solar energy to produce clean water from various water sources (seawater, desalination effluent with high salinity, industrial wastewater, etc.). Recently, researchers mainly focused on improving the evaporation performance of solar evaporators with advanced materials and paid less attention to treating high-salinity brine and wastewater (including VOCs-free wastewater and VOCs-containing wastewater). There are two challenges when treating the above solution: (1) The accumulated salts on the absorber surface will increase the reflection of sunlight, block water transmission channels, and thus decrease evaporation performance. (2) The contaminants, especially volatile organic compounds (VOCs), will enter distilled water with evaporation and thus reduce the quality of generated water. Herein, we systematically analyze the salt transport mechanism and propose universal schemes to maintain the evaporation surface unsaturated by adjusting the operation mode. We also summarized strategies to realize stable desalination of interfacial solar evaporators in high-salinity brine. In addition, we generalized interfacial solar evaporators integrated with other chemical or physicochemical methods to treat wastewater, which expands the application prospect of the solar-driven interfacial evaporation technology. Finally, we discussed the challenges and solutions when solar evaporators were used in water purification to provide some suggestions for the practical application of solar evaporators.