Photocatalytic Degradation of 1,2,4-Trichlorobenzene by Co₃O₄ under Visible Light: Kinetics and Mechanism

This study investigates the photocatalytic degradation capabilities of Co₃O₄ synthesized via the sol–gel method for 1,2,4-trichlorobenzene under visible light. Characterization of the composites through scanning electron microscopy (SEM), X-ray Diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FTIR) confirmed the formation of a cubic-phase structure. The photocatalytic performance of the synthesized Co₃O₄ was rigorously evaluated using the Langmuir–Hinshelwood model across various operational parameters, including catalyst dosage, initial pollutant concentration, reaction temperature, pH, and the presence of impurities such as humic acid, hydrogen peroxide (H₂O₂), and surfactants. Optimal conditions for the degradation process were determined to be a catalyst dosage of 2.0 g/L, an initial 1,2,4-trichlorobenzene concentration of 7.5 mg/L, and a reaction temperature of 30 ℃. Degradation efficiency was found to decreasenear neutral pH levels. Notably, the presence of humic acid had a negative impact on the degradation rate, while cationic surfactants and H₂O₂ served to enhance the photocatalytic process. Additionally, the degradation pathway and mechanism of 1,2,4-trichlorobenzene were predicted and validated, providing essential insights into its photocatalytic conversion. These findings underscore the effectiveness of synthesized Co₃O₄ in the photocatalytic degradation of 1,2,4-trichlorobenzene and highlight the significant influence of environmental conditions on the degradation efficiency. This study offers valuable insights for developing efficient photocatalytic systems for treating chlorinated organic pollutants under visible light.