Introduction: 4-chlorophenol is one of the common contaminants in wastewater resulted from chemical and petrochemical industries. This matter is resistant to biodegradation due to presence of chlorine and benzene ring in its structure. Various methods have been used to remove this contaminant from environment but the advanced oxidation techniques are more capable. In this study, proxone method (hydrogen peroxide plus ozone) was investigated to remove, 4-chlorophenol.

Materials & methods: This study is experimental and some parameters including pH, 4-chlorophenol initial concentrations, contact time, and the concentrations of oxidant (H₂O₂) during proxone process were investigated to remove 4-chlorophenol. All tests were conducted on actual solution (effluent of coal cleaning plant). Microsoft Office Excel 2013 software and SPSS 15 were used for data analysis.

Findings: The maximum removal efficiency of 4-chlorophenol at optimum condition (including pH=9, contact time=30 minutes, ozone concentration=0.09 g/hr, the initial concentration of 4-chlorophenol=100 ppm, the optimum concentration of H₂O₂=0.001 molar) were achieved 96.8% and 92.65% for synthetic and actual solution, respectively.

Discussion & conclusions: Advanced oxidation, according to Peroxone method is a suitable way to remove 4-chlorophenol and is able to remove this material from actual wastewater with efficiency of 92.65%. So, this method can be used for water purification and contaminated wastewater with this pollutant.