Thermal insulation design for efficient and scalable solar water interfacial evaporation and purification

In recent years, solar desalination and water evaporation/purification with various artificial architectures have drawn significant attention. Herein, we introduce a rational design structure for efficient solar water evaporation and purification, focusing on the balance between water transportation and thermal insulation. Natural wood after a simple flame treatment on the surface was utilized as the solar absorber, with a high solar absorbance (∼90 %), good hydrophilicity, and excellent heat localization abilities. Besides, a thermal insulator (polystyrene foam) was used to further reduce the thermal loss, and the optimized ratio between the water path and thermal insulator was obtained. A set of floating foam-flamed-wood (F-F-wood) devices were fabricated with a high evaporation rate of 3.92 kg m−2 h−1, exhibiting photothermal purification abilities from seawater and wastewater containing organic dyes and heavy metals. This study sheds light on the rational design of scalable and low-cost devices for solar water evaporation and purification.