Low-Carbon Fabrication of Fluorine-Free Superhydrophobic Copper-Based Materials for Acquiring Freshwater

By utilizing the etching reaction between a hydrophobic copper mesh (CuM) and an alkali solution to obtain a superhydrophilic copper mesh (AT CuM), and then only depending on the modification of linoleic acid (LA) at room temperature, a fluorine-free superhydrophobic copper-based material (CuM@Cu(OH)₂@LA) was fabricated. Subsequently, a funnel-shaped fog collector was constructed by simple folding for fog collection, which collected 10 400 mg of water with a water-harvesting rate (WHR) of 13.9 mg min^-1 cm^-2 after 30 min. Meanwhile, the AT CuM was deposited with polydopamine to obtain a photothermal nonfluorinated superhydrophobic copper base material (CuM@Cu(OH)₂/PDA@LA). CuM@Cu(OH)₂/PDA@LA was folded in the shape of a boat, filled with degreasing cotton, and placed upside down for seawater desalination as the (CuM@Cu(OH)₂/PDA@LA)/degreasing cotton photothermal interface evaporation device ([(CuM@Cu(OH)₂/PDA@LA)/DC]-PTIED). Thanks to its photothermal effect and superhydrophobic property providing the possibility of desalination, the evaporation device was capable of photothermal heating and floating on the water, achieving an evaporation rate of up to 1.85 kg m^-2 h^-1 under seawater outdoor simulation test conditions. Condensed water, which was desalinated by [(CuM@Cu(OH)₂/PDA@LA)/DC]-PTIED, met the World Health Organization (WHO) drinking water standards. In terms of durability analysis, both products maintained good wettability and performance after continuous 12 h mechanical abrasion, immersion in water, and UV irradiation. As a result, these two copper-based non-fluorine superhydrophobic materials had the advantages of superior performance, a simple preparation path, convenient operation, a mild reaction process, sustainable energy saving, and good application durability, providing a new perspective for the large-scale and low-cost production of freshwater resources in a low-carbon and sustainable way in underdeveloped areas.