A multifunctional biomass-based solar interface evaporator with feather-like structure for efficient selective transport, antibacterial properties, salt resistance, and oil-fouling prevention

Solar interface evaporation technology has gained prominence as an efficient, low-cost, and CO 2 -neutral method for water purification. However, the development of interface evaporators with high evaporation efficiency, durability, and environmentally friendly, cost-effective materials remains a significant challenge. In this study, we fabricated a novel solar-powered hydrogel membrane using sodium alginate (SA), reduced graphene oxide (RGO), and vegetable-tanned collagen fibers (CF). Utilizing a dual-structural engineering design strategy, which incorporates surface patterning and microfiber channel construction, the resulting sodium alginate/collagen fibers/reduced graphene oxide (CF/SA/RGO) composite membranes exhibited remarkable selective mass transport efficiency. The inclusion of vegetable-tanned collagen fibers notably enhanced the flow rate of free water within the CF/SA/RGO membranes. Moreover, the reduction in water evaporation enthalpy increased with successive GO reduction cycles, thereby further boosting the evaporation rate. The CF/SA/RGO membranes demonstrated an outstanding evaporation efficiency of 2.88 kg m −2  h −1 , ion rejection rates of 98 % for K + , Ca 2+ , Na + , and Mg 2+ , and a dye removal efficiency of 99.52 % for RhB, MB, MO, and CR. Additionally, these membranes exhibited excellent underwater oleophobicity, antibacterial properties, and salt resistance. This study offers a novel approach to the design and fabrication of solar interface evaporators, presenting an advancement in achieving high solar energy conversion efficiency and superior operational durability.