Fe-based metal organic frameworks decorated wood for efficient solar-driven interfacial water evaporation

The shortage of water resources in today's society requires humans to produce freshwater resources under harsh conditions (seawater desalination or sewage purification). Using solar energy as a heat source for water evaporation is the most environmentally friendly and sustainable way to produce fresh water. Traditional solar evaporation systems have large heat losses and low evaporation efficiency. Solar-driven interface evaporators can concentrate heat at the water–air interface, thus greatly improving the efficiency of water evaporation. The development of photothermal materials with excellent light-to-heat conversion ability is of great significance for the development of solar-driven interfacial evaporators. Herein, we introduce an evaporator based on wood, which is obtained through delignification, followed by freeze-drying treatment, then surface carbonization, and finally Fe-based metal organic frameworks loading, for effective solar-interfacial evaporation. The outstanding feature of the developed evaporator is that it exhibits excellent ultraviolet to near-infrared light absorbing capacity and high heat conversion efficiency, which can realize the rapid increase of the evaporator's surface temperature within 10 min. On the other hand, the high hydrophilicity of the evaporator ensures rapid water transportation. Therefore, the evaporation rate of metal organic frameworks decorated wood reaches a value up to 1.81 kg m-2h−1 and exhibits an evaporation efficiency of 89 % under 1 sun-illumination. In the self-desalination capacity test, the composite evaporator with geometric dimensions of 4 cm2 achieved an efficient removal of 1 g of NaCl in 1 h. In the simulated sewage purification experiment, the purification rate of tetracycline, methyl orange, and rhodamine B solutions reaches 93.2 %, 100 %, and 99.3 %, respectively, indicating that the developed evaporator can be considered as potential candidate for environmental safety applications.