Bionic solar-Driven interfacial evaporator for synergistic photothermal-Photocatalytic activities and salt collection during desalination

Abstract

Solar-driven interfacial evaporation plays an essential part in the production of potable water. Nevertheless, the intricate water conditions in real-world scenarios continue to pose limitations on its utilization. This study prepared a novel bionic PPy/BiVO4-PI/MXene aerogel composite material with radial center structure through directional freezing as the evaporator, which integrates both photothermal and photocatalytic properties into the evaporation system. In order to evaluate the efficacy of photocatalytic degradation and salt collection during interfacial evaporation, high-concentration saline water, simulated seawater and dyeing wastewater were employed as substitutes for real contaminated water bodies. After being exposed to 1 kW/m−2(−|-) of irradiation, the PPy/BiVO4-PI/MXene composite exhibits an evaporation rate of 1.64 kg m-2h−1 and achieves a photothermal efficiency of 96.77 %. In high-concentration saltwater containing 20 wt% NaCl, the PPy/BiVO4-PI/MXene exhibited an evaporation rate of 1.32 kg m-2h−1 and a photothermal conversion efficiency of 77.41 %. Furthermore, approximately 26.7 g of salt can be collected after 15 days’ continuous evaporation. Furthermore, the PPy/BiVO4-PI/MXene demonstrated exceptional photocatalytic capabilities to organic dyes such as MB, RhB, CR and MG with removal efficiencies of 79.28 %, 70.96 %, 76.70 % and 80.95 %, respectively. This study realizes the synergistic effect of interfacial evaporation, photocatalysis and salt collection, providing a highly promising choice for the treatment of high-salt dyeing wastewaters.