Salvinia\nnatans-Based\nHierarchical Structures for Solar Thermal Clean Water Production from\nHigh-Salinity Wastewater

Biomaterial-based solar-driven evaporation has great\npotential\nfor wastewater treatment and seawater desalination with a high energy\nconversion and utilization efficiency. However, technology gaps still\nexist for effectively and directly applying multiscale structures\nand intrinsic water transport channels of natural materials to enhance\nhigh-efficiency photothermal evaporation. In this study, a high-performance\nbiomass-derived photothermal evaporative material was obtained using Salvinia natans, a common aquatic floating plant,\ntogether with simple poly(<i>m</i>-phenylenediamine) oxidation\nmodification, building a hybrid biomass evaporator. With advantageous\nnatural features of adequate water transport, microscale–nanoscale\nhierarchical structures, effective water activation, and antisalt-fouling\nfunction, the hybrid biomass evaporator achieves a high evaporation\nrate of 2.24 kg m<sup>–2</sup> h<sup>–1</sup> under\none sun radiation (1 kW m<sup>–2</sup>). In addition, modified Salvinia natans also demonstrate certain ability\nto remove heavy metals during the photothermal evaporation of wastewater.\nThis work offers a new perspective on the synthesis of an environmentally\nfriendly and cost-effective solar-driven evaporator material, which\nhas the advantages of low cost, simple process, and high photothermal\nconversion efficiency, and can be widely applied to seawater desalination\nand the treatment of wastewater with high salt concentrations.