Investigating the Performance of Peroxymonosulfate to 4-Chlorophenol removal from Aqueous Solutions in the Presence of Manganese-containing Catalyst

Advanced oxidation processes based on peroxymonosulfate (PMS) have shown significant potential for the degradation of hazardous organic pollutants in wastewater. Manganese compounds are considered as environmentally friendly and desirable catalysts for PMS activation. In this study, MnOOH catalyst was synthesized in laboratory and used as a PMS activator to remove 4-chlorophenol (4-CP), which is one of the most important derivatives of the chlorophenol family.

effective operational parameters including MnOOH dose (0.01, 0.05, 0.1, 0.2, 0.3, and 0.5 g/L), PMS dose (0.2, 1, 2, and 4 mmol), initial 4-chlorophenol concentration (25, 50, 100, and 200 mg/L) and the initial pH of the reaction solution (3, 5, 7, 9, and 11) on the 4-CP removal efficiency were studied. Also, the effect of coexisting anions (bromide (Brˉ) and phosphate (PO43ˉ)) and humic acid was studied in order to identify how the process works in different conditions. Finally, the catalyst reusability experiment was carried out in order to determine the stability and reusability of the MnOOH.

The results showed that the best performance of PMS/MnOOH process (4-chlorophenol degradation efficiency equal to 94.88%) is obtained in neutral pH conditions, PMS dose equal to 2 mmol and MnOOH dose equal to 0.3 g/L. in the presence of phosphate, the degradation efficiency of 4-chlorophenol in PMS/MnOOH was significantly decreased. Also, MnOOH showed acceptable stability in reusability tests.

Advanced oxidation process of PMS/MnOOH as a powerful, sustainable and environmentally friendly system can be used in the treatment of wastewater containing phenolic compounds, especially 4-chlorophenol.