Oil-Resistant and Wood-Inspired Superhydrophilic Poly(Vinyl Alcohol) Aerogel with Vertically Aligned Channels for Effective Solar Interfacial Desalination and Wastewater Treatment

Environmental pollution and sewage surges necessitate effective water purification methods. Solar interfacial evaporation offers a promising solution, which needs advancements in salt resistance, efficiency, and stability. Herein, inspired by the structure of wood, the unidirectional freeze-drying method was used to develop the vertically aligned channels and antioil-fouling poly(vinyl alcohol)-CNTs-waste carton fiber@polydopamine (PVA-CNTs-WCF@PDA) aerogel for desalination and wastewater treatment. The anisotropic three-dimensional porous structure of the aerogel enables it to rapidly transport water to the evaporation interface and resist salt deposition. Meanwhile, its unique structure is combined with CNTs and PDAs with excellent broadband spectral absorption capacity because the composite aerogels can interact with water molecules to reduce their water vaporization enthalpy. The composite aerogel shows an excellent photothermal evaporation rate (2.626 kg m-2 h-1) and efficiency (94.24%) under one-sun irradiation. Additionally, the composite aerogel interface evaporator can conduct 10 consecutive evaporations in 3.5% brine, indicating that it has the ability to desalination. Finally, it is also used to purify an oil-in-water emulsion and mine wastewater. It can be seen that there are no obvious oil droplets in the treated emulsion and that the treatment effect of mine wastewater reaches 89.13%. The composite aerogel showed excellent application prospects in the field of water purification.