Distribution of perfluorinated compounds in drinking water treatment plant and reductive degradation by UV/SO32− process

• Published in: Environmental science and pollution research international Vol. 25; no. 8; pp. 7443 - 7453
• Main Authors: Sun, Min, Zhou, Hao, Xu, Bei, Bao, Junxin
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.03.2018
• Subjects: Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Research Article; Waste Water Technology; Water Management; Water Pollution Control; Drinking water; Reductive degradation; Perfluorinated compounds; UV/SO
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-017-1024-9

Perfluorinated compounds (PFCs), which are widely used in industrial and residential areas, have a large negative impact on the environment. This study investigated the removal efficiency of five PFCs in a drinking water treatment plant. The results indicate that the total PFC concentration in raw water is 261.51 ng L −1 and that perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) are the predominant pollutants. Among all of the treatment processes, coagulation sedimentation process had the highest removal ratio of PFCs (36.12%), and removal ratio was the least in the sand filtration process. The ozonation/activated carbon and disinfection processes increased the concentration of PFCs. Therefore, developing an effective treatment to degrade PFCs is feasible. In this study, we proposed a method using UV irradiation of SO 3 2− at 365 nm to degrade PFCs. The SO 3 2− concentration, pH, and initial concentration had profound impacts on the degradation of PFCs. When the PFC initial concentration was 20 mg L −1 , the SO 3 2− concentration was 2.4 g L −1 , and in the presence of buffer, the degradation of PFCs was the most efficient, with the degradation ratio close to 100% after 60 min of reaction. During the degradation of PFCs, short-chain PFCs and hydrofluorinated carboxylic acid were generated. From the above, we proposed a detailed mechanism of degradation and its possible pathways.