Waste silk-derived photothermal aerogel for efficient interfacial solar desalination

The textile industry is a major contributor to environmental pollution and generates substantial waste each year. Recycling waste fabrics has garnered significant research interest, especially in addressing the urgent global challenge of freshwater scarcity. Interfacial solar desalination (ISD) is highly valued for its energy efficiency and environmental advantages. However, its application in desalination is hampered by various challenges, including low evaporation rate (ER) and insufficient salt resistance. In this study, a sustainable photothermal aerogel (PTA) made of polypyrrole (PPy)-decorated waste silk (WS) was developed, called PPy-WS-PTA, for efficient ISD. This PTA absorbs up to 96 % of sunlight. As a three-dimensional (3D) material, PPy-WS-PTA can capture energy from its surroundings. At an exposure height of 3 cm, the PPy-WS-PTA attains an ER of 2.04 kg m –2 h −1 under 1-sun. Due to its excellent water transport and storage capabilities, the PPy-WS-PTA can withstand 20 wt% saltwater while maintaining a stable ER of 1.61 kg m –2 h −1 . Outdoor desalination experiments have demonstrated that the PPy-WS-PTA can effectively desalinate 20 wt% saltwater. This PTA not only addresses freshwater shortages but also helps reduce fabric waste pollution and enhances reutilization efficiency.