Multifunctional Aerogels as Efficient Solar Evaporators for Seawater Desalination and Wastewater Treatment

Interfacial solar steam generation technology has emerged as a promising desalination technology owing to its cost-effectiveness and sustainability. However, traditional evaporators often face challenges, including significant heat loss and low photothermal conversion efficiency. To address these challenges, we report a rationally designed three-dimensional solar evaporator (SG3) featuring an integrated aerogel system that combines the three core functions of water transport, thermal insulation, and photothermal conversion into a monolithic structure, thereby overcoming the key limitations of conventional evaporators. The SG3 evaporator consists of a hydrophilic sodium alginate/aramid nanofiber (SA/ANFs-30) aerogel for efficient water transport, a hydrophobically modified SA/ANFs-Si4 aerogel as thermal insulation and buoyant support, and a photothermally enhanced SA/ANFs-Ag/Ti3C2Tx aerogel incorporating Ag nanowires and Ti3C2Tx MXene for solar absorption. The optimized evaporator achieves 97% broadband light absorption across the solar spectrum, an evaporation rate of 2.69 kg m–2 h–1, and a photothermal conversion efficiency of 96.5%. Furthermore, the SG3 evaporator maintains stable evaporation performance for 6 h in high-salinity brine (20 wt %), demonstrating reliable salt rejection capacity. The integrated system also enables effective treatment of complex wastewater streams containing heavy metal ions, acidic/alkaline solutions, and organic dyes. This work provides valuable insights into the design of high-performance solar evaporators for practical desalination applications.