Multifunctional biomass-based solar evaporator with enhanced sterilization performance for solar-driven clean water evaporation

Abstract

Solar-driven interfacial evaporation presents an important technology in dealing with the global freshwater crisis due to its highly effective solar-to-vapor conversion, minimal environmental impact, and off-grid application. However, the high material cost, complex fabrication process, and lack of effective sterilization limit its scaled-up application. Herein, we demonstrate an efficient multi-functional, biomass-based (MBB) photothermal evaporator using CuO nanoparticle-modified, carbonized peanut shells in a low-cost and scabble way. With highly efficient solar absorption, localized heating, and water transport, the MBB photothermal evaporator achieved a ∼ 91.1 % solar-to-vapor efficiency under sunlight illumination with a clean water production rate of 1.46 kg m−2 h−1. A similar evaporation rate of 1.41 kg m−2 h−1 was obtained directly from wastewater or seawater with a wide range of pH (2–14). The experiments showed that the collected water is relatively clean with complete removal of Escherichia coli and Staphylococcus aureus by damaging bacterial cell walls. 99 % of methylene blue and rhodamine B can also be effectively removed, benefiting from the formation of chelating and hydrogen bonds with the OH groups on the surface of MBB. This research provides a new environmentally sustainable photothermal evaporator for water purification, specifically designed to benefit economically stressed communities.