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Degradation of 4‐Chloroguaiacol by Dark Fenton and Solar Photo‐Fenton Advanced Oxidation Processes

This paper evaluates the dark Fenton and the solar photo‐Fenton advanced oxidation processes for the treatment of solutions containing 4‐chloroguaiacol (4‐CG). The 4‐CG was chosen as a model compound found in pulp and paper wastewater formed in the bleaching process in the pulp industry. The effects of operating parameters, including reaction time, hydrogen peroxide‐to‐ferrous iron molar ratio (H2O2/Fe2+), initial chemical oxygen demand (COD), pH value, and temperature, on 4‐CG degradation efficiency using the solar photo‐Fenton process were investigated. It was demonstrated that both processes could effectively degrade 4‐CG in water and followed first‐order kinetics. The degradation rate in solar photo‐Fenton oxidation was much faster than that of the dark reaction. The 4‐CG degradation depends on its concentration in the solution. The degradation efficiency decreases when the concentration of the 4‐CG increases. Under the conditions of pH 3, H2O2/Fe2+ molar ratio 2, H2O2 16 mmol·L−1, Fe2+ 8 mmol·L−1, initial COD 640 mg·L−1, reaction time approximately 24 minutes, and temperature 25°C, the 4‐CG and COD percent removal were greater than 80 and 89%, respectively.