Background and purpose: Chlorophenol compounds are refractory and toxic contaminants that enter the environment as a result of industrial activities. They can contaminate water sources through leaking into the groundwater or being washed out from polluted soil. The aim of the present study was to evaluate the rate of 4-Chlorophenol (4-CP) degradation using the UV/NaPS process.

Materials and methods: In this investigation, the photochemical oxidation process was conducted in a batch type laboratory-scale photoreactor (1.5 L) equipped with a 50000  power. This study also investigated the effects of independent variables including sodium persulfate concentration (8.4-84 mmol/L), pH (3-10), 4-CP concentration (0.5.5 mmol/L), and reaction time (2-30 min) on the removal efficiency of 4-CP. The effluent concentration of 4-CP was measured by the UV-visible spectrophotometer at 280 nm wavelength. In addition, kinetic model was investigated.

Results: The optimum removal efficiency of 4-C by UV/NaPS process was 89.3% with sodium persulfate concentration of 8.4 mmol/L, pH of 5, initial 4-CP concentration of 1.5 mmol/L, and reaction time of 30 min. Moreover, 60.4% of the total organic carbon (TOC) was removed under similar condition. In addition, the data was found to follow the first-order kinetics.

Conclusion: Considering the growing use of UV radiation in water treatment processes and the considerable efficiency of UV/NaPS process in removing 4-CP, this method can be proposed for the elimination of 4-CP after performing cost-benefit analyses.