Sustainable Interfacial Evaporator Fabricated from Delignified Wood for Wastewater Treatment

The rapid pace of industrialization and population growth has led to a dramatic increase in the discharge of industrial, dye-laden, and heavy metal-contaminated wastewater, intensifying a global crisis of water pollution and freshwater scarcity. Solar-driven interfacial evaporation has emerged as a promising and sustainable technology for clean water production. However, its practical application is hindered by factors such as salt accumulation and heavy metal buildup. To overcome these limitations, this study presents an environmentally friendly evaporator constructed from lightweight balsa wood. Through a delignification process, we converted the natural wood into delignified wood (DW) featuring a highly hydratable cellulose network with unobstructed vertical channels. Subsequently, a cost-effective and biodegradable photothermal layer was formed on this DW framework via the copolymerization of cuttlefish ink powder (CM) with polydopamine hydrochloride (PDA), yielding the final CPW evaporator. Under 1 sun, the CPW evaporator achieves a high evaporation rate of 2.40 kg m^-2 h^-1 with an efficiency of 95.8% in a 10 wt % NaCl solution, demonstrating exceptional desalination capability. Moreover, it exhibits outstanding performance in wastewater remediation, efficiently purifying dye-contaminated water, as well as acidic and alkaline solutions, with the collected condensate showing a neutral pH. By integrating green photothermal materials with a rationally designed wood-based structure, this work offers a highly efficient strategy for addressing complex industrial organic wastewater pollution, highlighting its significant potential for practical water treatment applications.