Efficient Removal of Perfluorooctanoic Acid by UV-Based Peroxide and Persulfate Advanced Oxidation Processes

Abstract

Perfluorooctanoic acid (PFOA) challenges traditional methods of aquatic treatment and recycling from recalcitrant organic compounds, which ubiquitously persist in the environment, mainly water bodies, and cause various adverse effects on humans and the environment. Conventional water treatment technologies are proven inefficient and must focus on advanced oxidation processes. This study conducted treatability studies for removing PFOA by direct photolysis, UV/peroxide, and UV/persulfate oxidation using a lab-scale reactor. The experiment was performed with an initial concentration of 20 mg/L for 120 min for a 500 mL of sample. The oxidant dosage and pH were optimized based on the mineralization efficiency. An efficient method for PFOA degradation is based on its percentage reduction in concentration, mineralization efficiency, and reaction kinetics study. It was found that all three processes were adequate for mineralizing PFOA. Among them, UV/persulfate was more effective in mineralizing PFOA. The total organic carbon removal percentages using direct photolysis, UV/persulfate, and UV/peroxide treatments were 49%, 80%, and 66%, respectively. The pseudofirst-order kinetics for these three were 0.160, 0.489, and 0.349 h−1, respectively.