Interfacial Solar Evaporation for Treating High-Salinity Wastewater: Chance and Necessity

The tension in the relationship between water and energy seriously restricts the harmonious coexistence between man and the ecological environment. The solar-powered interface evaporation technology emerging in recent years has shown good application prospects in high-salt wastewater treatment for achieving the zero-discharge treatment of wastewater. In this review, advanced solar-driven interfacial evaporation is primarily focused on its mechanisms, photothermal materials optimization, and the structure of solar evaporators for salt removal. The high wide-spectrum solar absorption rate of photothermal materials determines the total energy that can be utilized in the evaporation system. The light-to-heat conversion capacity of photothermal materials directly affects the efficiency and performance of solar interface evaporators. We highlight the microstructures enabled by the nanophotonic designs of photothermal material-based solar absorbers, which can achieve highly efficient light harvesting across the entire solar irradiance spectral range with weighted solar absorptivity. Finally, based on current research, existing problems, and future development directions for high-salt wastewater evaporation research are proposed. The review provides insights into the effective treatment of high-salt wastewater.