High-efficiency solar seawater evaporator by foam with hierarchically ordered channels based on carboxymethylated regenerated cellulose fibers

Solar energy-driven water evaporation technology presents a sustainable method for seawater desalination and wastewater treatment. However, creating a biomass-based interfacial evaporator that achieves high salt resistance and rapid evaporation rates remains a significant challenge. In this study, we prepared a novel foam from carboxymethylated regenerated cellulose fibers, leveraging their natural orientation properties and excellent hydrophilicity. This foam featured hierarchically ordered water transport channels and numerous hydrophilic groups, which enhanced water transport efficiency and decreased the enthalpy of evaporation. The incorporation of polypyrrole gave it effective photothermal conversion properties. The foam demonstrated strong performance in solar-driven water evaporation, achieving an evaporation rate of 3.57 ± 0.04 kg m −2  h −1 under simulated sunlight conditions, with an evaporation efficiency of 93.8 ± 1.5 % and a notable ability to resist salt. This research provides a practical solution for sustainable desalination and holds great potential for the future development of desalination evaporators.