A Self-floating Photothermal/Photocatalytic Evaporator for Simultaneous High-Efficiency Evaporation and Purification of Volatile Organic Wastewater

Solar-driven photothermal interfacial evaporation technology is considered as a promising green approach to alleviating the global water resources crisis. However, efficient removal of volatile organic compounds (VOCs) from both the bulk and the distilled water remains a significant bottleneck in this technology. Here, drawing inspiration from the natural structure and transpiration mechanism of trees, a self-floating solar-driven evaporation/photocatalytic integrated system (MCPWC) has been built utilizing a novel combined material consisting of Mn@g-C₃N₄/PANI/wood-derived carbon. The unique design of the evaporator resulted in an outstanding evaporation performance (2.99 kg m⁻² h⁻¹), along with an impressive photothermal conversion capability (97.06%). Notably, the modification of g-C₃N₄ by metal Mn promoted the separation-migration of photo-induced electron-hole pairs, thereby enhancing the degradation of target pollutants. In addition, the introduction of polyaniline (PANI) not only serves as an efficient photothermal absorber, but also a co-catalyst, forming a synergistic catalytic system with Mn@g-C₃N₄ to actualize the efficient degradation of VOCs (95.69% of bulk water and 99.04% of distilled water). Thus, this MCPWC evaporator successfully incorporated photocatalytic degradation into the solar evaporation system, providing revolutionary insights into the treatment of contaminated wastewater and paving a new path for the production of high-quality freshwater.