Carbonized Bark by Laser Treatment for Efficient Solar-Driven Interface Evaporation

Interfacial localization of solar thermal energy conversion to drive evaporation is a promising water treatment technology, especially for gaining pure water in freshwater-deficient areas. Phoenix tree bark is chosen as the raw material mainly because of its low cost and renewability. The carbonized bark with broadened pore sizes possess efficient steam escape channels and light absorption structure. The film with a double-layer structure is constructed through converting the surface of the bark into the carbonized structure under controllable laser treatment. The evaporation efficiency is calculated to be 74% under 1 sun by enhancing the photothermal conversion ability and efficiently opening the surface water transport channels simultaneously. The distillation water exhibits large resistance values (9.65 MΩ) and low concentrations of four primary ions (Na⁺, K⁺, Mg²⁺, and Ca²⁺), which achieves international standard for drinking water. In addition, the carbonized bark also exhibits all-right purified performance toward water evaporation from dye wastewater. The low cost and clean technology provides new inspiration for the future development of applicable solar thermal energy-driven water treatment systems.