Transforming waste aramid fibers and carbon fibers into aerogels for efficient solar-driven water desalination

Solar energy is an abundant renewable source of energy for seawater desalination. Interfacial solar water evaporation technology based on photothermal processes is one of the most effective ways of utilizing solar energy. However, practical challenges such as low efficiency, complexity, and poor durability, have hindered the widespread adoption of this technology. To tackle these challenges, research has been focused on developing materials that exhibit broad-spectrum light absorption, high mechanical and thermal stability, and low thermal conductivity. Moreover, growing waste from high-performance materials such as aramid fibers and carbon fibers highlights the need for sustainable practices, such as upcycling these fibers instead of relying on new resources. In this study, we have demonstrated the upcycling of waste aramid fibers and carbon fibers into aerogels for water evaporators. The incorporation of MXene into the aerogels has significantly enhanced light absorption compared to both ANF and ANF-CF aerogels. This improvement, along with increased photothermal efficiency and hydrophilicity, led to an optimized structure with a solar-to-vapor conversion efficiency of 103.6 % and an evaporation rate of 1.63 kg m⁻² h⁻¹ under one sun. The MXene/aramid fiber/carbon fiber aerogels, with their three-dimensional structure, provided the foundation for the development of stable solar interfacial evaporators that could efficiently convert seawater into clean drinking water through high light absorption and mechanical stability.