Tree-inspired efficient solar evaporation and simultaneous in-situ purification of ultra-highly concentrated mixed volatile organic wastewater

The high concentration, complexity and volatility of organic pollutants in actual wastewater are becoming major obstacles to realizing efficient water purification. Inspired by the structure and physiological process of trees, a two-in-one solar-driven evaporation/photocatalysis system for efficient water evaporation and in situ purification was fabricated from wood-derived porous carbon that was vertically aligned and uniformly loaded with polymetallic oxide nanoparticles. The system enabled rapid water evaporation (up to 3.23 kg m-2 h-1) and effective purification of mixed volatile wastewater containing rhodamine B, phenol and tetracycline with ultra-high total concentration of up to 11700 mg L-1 under 1 sun irradiation, which was significantly higher than that reported previously, and distilled water with undetected volatile pollutants could be simultaneously obtained. The combination of nanoparticles and wood hierarchical structures provided photothermal conversion substrates, catalysts and reaction/transmission channels for efficient water evaporation and in situ pollutant degradation and achieved the synergistic promotion of photothermal conversion and photo-Fenton reactions. This process provides a novel and promising strategy for the efficient treatment of highly concentrated mixed volatile organic wastewater.