3D aerogel membrane-based evaporator with sandwich structure for superior solar-driven evaporation

Seawater desalination with solar-driven interfacial evaporators has emerged as a promising solution to alleviate global water scarcity. However, conventional two-dimensional (2D) planar evaporators have high reflectivity, which poses a challenge in achieving efficient light absorption. Herein, a sandwich-structured solar-driven interfacial evaporator (SSIE) assembled with three-dimensional (3D) cellulose aerogel membranes (modified with TiN nanoparticles) and an air-laid paper was proposed, which is significantly different from the previously reported 2D membrane-based evaporators. Cellulose aerogel membranes have excellent integrated properties, including extremely high flexibility, allowing for multiple folds, and a 3D porous structure that enables multiple light absorptions. Benefiting from special structural design, SSIE achieves an outstanding evaporation rate of 2.20 kg m−2 h−1 and an energy efficiency of 83.30%. Moreover, SSIE maintains a stable evaporation rate throughout a 10 h saltwater evaporation process. It also demonstrates excellent performance in seawater and simulated wastewater purification. Furthermore, SSIE exhibits a significant purification effect for dye wastewater, such as Rhodamine B (RhB). This study provides valuable insights into rational structural design for solar evaporators, as well as holding tremendous potential for carrying out seawater desalination in limited spaces.