Preparation of TiO2/Sponge Composite for Photocatalytic Degradation of 2,4,6-Trichlorophenol

Photocatalysis has emerged as a promising approach for treating environmental pollution. In this study, TiO2/sponge composites with good photocatalytic activity in visible light were prepared via a simple and efficient low-temperature process and applied to the degradation of 2,4,6-trichlorophenol (2,4,6-TCP) present in papermaking wastewater. The process conditions for preparing TiO2/sponge composites were optimized by varying the TiO2 dosage, cellulose dosage, and surfactant concentration. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) results showed that TiO2 successfully adhered to the sponge surface and that the composites achieved a good recycling effect. Degradation occurred under visible light, and a degradation rate of 81% for 2,4,6-TCP with initial concentration of 20 mg/L was achieved in 4 h. The fragments were analyzed using ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS), which revealed the formation of 2-hydroxyvaleric acid (2-HVA) as a degradation product; a possible degradation mechanism is proposed to interpret these findings. Visible-light photocatalysis shows high potential for the rapid and environmentally friendly destruction of organic pollutants in papermaking wastewater.