In situ generation of hydroxyl radical for efficient degradation of 2,4-dichlorophenol from aqueous solutions

Since 2,4-dichlorophenol (2,4-DCP) as a priority pollutant is used in numerous industrial processes, its removal from the aqueous environment is of utmost importance and desire. Herein, the authors describe an electrochemical treatment process for efficient removal of 2,4-DCP from aqueous solutions using electro-Fenton (EF) process. Response surface methodology (RSM) was applied to optimize the operating parameters. Analysis of variance (ANOVA) confirmed the significance of the predicted model. The effect of independent variables on the removal of 2,4-DCP was investigated and the best removal efficiency of 98.28% achieved under the optimal experimental condition including initial pH of 3, H₂O₂ dosage of 80 μL, initial 2,4-DCP concentration of 3.25 mg L^-1, current density of 3.32 mA cm^-2, and inter-electrode distance of 5.04 cm. The predicted removal efficiency was in satisfactory agreement with the obtained experimental removal efficiency of 99.21%. According to the obtained polynomial model, H₂O₂ dosage revealed the most significant effect on degradation process. The kinetic investigation revealed that the first-order model with the correlation coefficient of 0.9907 and rate constant (K_app) of 0.831 min^-1 best fitted with the experimental results. Generation of the hydroxyl radicals throughout the EF process controlled the degradation process.