Highly Efficient, Salt‐Resistant, and Chemically Durable Solar Evaporator for the Purification of Industrial High‐Salinity Wastewater

Abstract Solar interfacial evaporation is a promising technology for producing clean freshwater from brine or wastewater with a minimal carbon footprint. However, its application is limited by its poor salt and oil resistance and chemical durability. In this work, a superhydrophobic/superhydrophilic solar interfacial evaporator (SS‐SIE) comprising a superhydrophobic top coated with carbon nanotubes is designed for absorbing light, a superhydrophilic bottom for pumping water, and resisting insoluble organic matter. Owing to this unique structure, salt deposition is confined to the superhydrophilic part, thereby ensuring the long‐term stability of the SS‐SIE for sustained (>100 h) solar evaporation in saturated brine, which is record‐breaking for salt‐resistant solar evaporators. Moreover, the chemical durability and oil resistance of the SS‐SIE are demonstrated. With these excellent properties, the SS‐SIE enables stable evaporation in industrial high‐salinity wastewater characterized by strong alkalinity, high salinity, and high organic content under 1 sun irradiation over 7 days. Notably, purified water can be directly used for cultivating plants without causing any toxic effects on their growth. Therefore, SS‐SIE provides an alternative, environmentally friendly, and efficient pathway for purifying industrial high‐salinity wastewater and broadening the range of solar evaporation applications.