Solar-driven interfacial evaporation and simultaneously photocatalytic mitigation of tylosin by using a hydrogel sponge-supported semiconductor composite.

Water resource shortage and water pollution are global challenges. Simultaneously obtaining clean water and mitigating pollutants from harsh water sources are continuously pursued in research community and industry sector. In this work, a TiO₂/g-C₃N₄/PPy@MS (TGP@MS) composite was fabricated to harvest water and mitigate tylosin from wastewater concurrently through a coupled process of solar-driven evaporation and photocatalysis. The composite presents exceptional hydrophilicity, broad-spectrum light absorption, and superior catalytic activity. Incorporating polysized phenylamine onto TiO₂/g-C₃N₄ enhanced infrared light absorption, extending the light absorption across the full solar spectrum range of 300-1200 nm and ultimately achieving an absorption rate of 91.6 % within this range. The 3D porous structure and the hydrophilic nature of the hydrogel sponge facilitated the capillary-driven water transport to surfaces. Under one sun condition, an evaporation rate of 1.49 kg/(m²·h) and a photothermal conversion efficiency of 89.4 % were achieved for TGP@MS. Active species including ·OH and ¹O₂ were generated from the TiO₂/g-C₃N₄ components, degrading 90 % of tylosin within 150 min. Due to the versatile purification capabilities, TGP@MS could treat a wide range of water samples, enabling simultaneous water recovery and pollutant removal. Therefore, this work demonstrates significant potential in addressing the water crisis in underdeveloped areas. It achieves this by simultaneously producing clean water and mitigating pollutants from low-quality water sources, using green and sustainable solar energy.