Novel Nanocellulose-Based Self-Floating and Salt-Collectible Evaporator Prepared by a 3D Template Method Applied for Multiscenario Water Evaporation

Solar-driven interfacial evaporation as a sustainable and green desalination method has a promising development prospect in the current severe water shortage situation. Nowadays, most research on this evaporation is focused on the selection of materials, photothermal efficiency, or desalting propeties, but the salt collect-ability, which has an important application for water treatment, especially in some salt-additive industries, has been ignored. Therefore, we proposed a self-floating and salt-collectible evaporator fabricated by composite modified polydopamine with waterborne polyurethane (WPU) and cellulose nanofibers (CNF) as substrate and rGO as photothermal material, featuring a concave structure made by a three dimensional (3D) template method. The results indicated that the composite aerogel can absorb up to 94.85% of sunlight and reach a high evaporation temperature during evaporation. The evaporation rate of concave composite aerogel evaporator (PPF) reaches 2.089 kg m –2 h –1 under standard solar irradiation with an energy conversion efficiency of 94.33%. In wastewater with high salt content, the salt production rate can reach 0.672 kg m –2 h –1, demonstrating its potential application in some industrial wastewater with high salt content and good salt collection with high recycle efficiency. In sum, this research provides new ideas and methods for efficient and sustainable desalination and wastewater treatment technologies, which are expected to play an important role in future practical applications.