Al-Foam-Based Solar Interfacial Evaporator Prepared by Picosecond Laser Combined with Fire Burning Used for High-Efficiency Solar Desalination, Water Purification, and Salt Resistance

Solar-driven interfacial evaporation technology represents an innovative and high-efficiency desalination approach. This technology plays a crucial role in relieving the shortage of worldwide freshwater resources. However, the interfacial evaporator still faces great challenges in terms of high efficiency and ensuring long-term evaporation stability, among other aspects. Here, a novel and simple interfacial evaporator based on foamed aluminum (Al) has been designed. This evaporator is made using a treatment process that combines picosecond laser treatment with fire treatment (LTF). Due to the porous channels, inherent hydrophilicity of the solar interfacial evaporator, and its laser-treated and fire-carbonized surface, it has an efficient light absorption rate (>99.9%) and a high efficiency (93.5%). In the indoor experiment, a water evaporation rate of up to 5.55 kg m^–2 h^–1 is achieved under 1 sun irradiation (1 kW/m²). During the evaporation of high-concentration brine with a mass fraction of 15%, the solar-driven water evaporation rate can still be maintained at 5.15 kg m^–2 h^–1. In outdoor environments, a freshwater collection amount of 6.81 kg m^–2 per day can be obtained. These works provide new ideas for the preparation of solar evaporators that are highly efficient, capable of long-term stable operation, and also promote the practical application of sustainable water purification technologies.