All-in-one design of wood evaporator with highly-efficient salt resistance for sustainable solar desalination and contaminated water purification

Solar steam generation combined with contaminated water purification provides a green and sustainable method to harvest fresh water from seawater or wastewater. However, essential challenges still exist in developing high-performance, multifunctional and durable evaporators. Herein, a novel wood evaporator composed of delignified balsa wood, reduced graphene oxide and partially reduced CuO/Cu 2 O nanoparticles is developed via an ultrasonic-assisted deposition technique. The synergistic effect of a 3-dimensional nanocomposite skeleton and formed heterojunctions facilitates a homogeneous distribution and sufficient interaction with water molecules, endowing the evaporator with superior optical, photothermal and solar evaporation performances. A superior evaporation rate of 2.10 kg·m −2 ·h −1 for pure water is achieved with an energy conversion efficiency of 83.39 % under 1 sun irradiation. Experimental and simulation tests further confirm the strong hydration ability of the wood evaporator to reduce the equivalent vaporization enthalpy. Meanwhile, the wood evaporator exhibits competitive salt resistance and reusability in seawater and even brines with extremely high concentration (20 wt%) in long-term irradiation, attributed to cooperative mechanisms including surface electro-negativity and interior three-dimensional salt diffusion. Stable self-floating, physical and chemical durability as well as photocatalytic antibacterial capabilities ensure long-term operation stability under harsh conditions. This work provides an efficient and potentially scalable solution for fresh water production and wastewater purification.