A Wood-Derived Janus Aerogel with Excellent Salt Resistance for Highly Efficient Interfacial Solar Evaporation and Wastewater Purification

Interfacial solar-driven steam generation, which is recognized as an emerging fresh water acquisition technique, has attracted widespread scientific attention recently. Developing stable and sustainable solar evaporators featuring desirable evaporation performance, wonderful salt rejection, and superior wastewater purification remains a sizable challenge. Herein, a Janus aerogel derived from natural balsa wood was successfully fabricated through facile procedures such as chemical removal, freeze-drying, and subsequent deposition. Benefiting from the commendable light absorption capacity and light-to-heat conversion ability, the resultant Janus aerogel achieved an evaporation rate of 1.62 kg m-2 h-1 with an efficiency of 83.3%. Continuous 6 h evaporation in a 20 wt % NaCl solution under 1 sun illumination evidenced its great salt resistance for steady evaporation with almost no aggregated salt crystals. Moreover, the designed aerogel presented an approximately 100% purification efficiency toward diverse types of wastewater. This cost-effective, ecofriendly Janus aerogel exhibited extensive application prospects in alleviating the water shortage dilemma and offered valuable insights for the construction of preeminent solar evaporators.