Degradation of Pentachlorophenol in Aqueous Solution by the UV/ZrO2/H2O2 Photocatalytic Process

Pentachlorophenol (PCP), which is one of the resistant phenolic compounds, has been classified in the category of EPA’s priority pollutants due to its high toxicity and carcinogenic potential. Therefore, its removal from water and wastewater is very important. Various methods have been studied for removing the compound, among which advanced oxidation processes (AOPs) have attracted much attention because of ease of application and high efficiency. Thus the aim of this study was to investigate the efficiency of the UV/ZrO₂/H₂O₂ process, as an AOP, for PCP removal from aquatic environments. The effects of several parameters such as ultraviolet (UV) exposure time, initial PCP concentration, pH, concentration of zirconium dioxide (ZrO₂) nanoparticles, and H₂O₂ concentration were studied. Kinetics of the reaction was also detected. The concentration of the stated materials in the samples was determined using a spectrophotometer at 500 nm. The results showed that the highest efficiency (approximately 100%) was reached at optimized conditions of pH 6, contact time of 30 minutes, initial PCP concentration of 20 mg/L, the nanoparticles concentration of 0.1 g/L and H₂O₂ concentration of 14.7 mM/L. Also, the process followed the first order kinetics reaction. The obtained results illustrated that the UV/ZrO₂/H₂O₂ process has a high ability in removing PCP.