Waste tissue-based bilayer solar evaporator for efficient solar photothermal generation of clean water

Solar photothermal water evaporation technology has attracted attention owing to its promising applications in wastewater treatment and desalination for producing clean water. However, high-performance solar evaporators are still limited by the complex manufacturing process, less flexibility, intolerance to salt, high cost, and low water evaporation efficiency.In this study, composite fibre paper composed of waste tissue paper, aramid nanofibers, and polyaniline was prepared to produce clean water. The evaporator was designed to pump water through a cotton wick to the composite paper, which reduced heat loss and avoided the deposition of salt on the surface. The use of waste tissue paper solves the problem of waste disposal, increases the commercial value of waste tissue, and reduces production costs. The composite fibre paper exhibited broad-band light absorption of an average of 96%. The average evaporation rate of the solar evaporator was 1.43 kg m^-2 h^-1, and the photothermal conversion efficiency was 98.33% under 1 sun illumination. This solar evaporator is easily fabricated and is cost-effective, demonstrating the enormous potential for real-world wastewater treatment and desalination to produce clean water.