| Summary: | 碩士 === 國立臺灣大學 === 環境工程學研究所 === 96 === Perfluorinated compounds (PFCs) are ubiquitous with their wide production and applications for more than half a century. Because of its persistence and potential health risk, the occurrence of PFCs in our environment is becoming an increased concern. Two compounds that receive most attentions are perfluorooctanoic acid (PFOA) and perfluorooctyl sulfonate (PFOS).
In this study, ten target PFCs, belonging to perfluoroalkyl sulfonate (PFAS) and perfluoroalkyl carboxylates acid (PFAC) groups, were identified with liquid chromatography tandem mass spectroscopy (LC/MS/MS).
The occurrence of PFCs in the electronic industrial plants was investigated. Low levels (μg/L) of PFOA and PFOS were found from different commonly used chemical materials in the photo developing processes. In the waste effluents of electronic industrial plants, three major constituents PFCs were identified, which were PFOS ( 0.1-179 μg/L), PFOA (1.6-172 μg/L),and perfuorodecanoic acid (PFDA) (0.1-82.8 μg/L). These could be the major sources of the PFCs detected downstream.
Three investigated receiving water bodies (Keya, Touchien, and Xiaoli Rivers) also demonstrated to have significant amount of PFCs. In Keya River, PFOS and perfluorohexyl sulfonate (PFHxS) occurred at 5.44 and 2.24 μg/L respectively. Other PFCs were found in ng/L level. In Touchien River and Xiaoli River, most of the PFCs were identified in ng/L level, and again PFOS, PFOA and PFDA are the dominate species. Xiaoli River and Touchien River are located on the upstream of drinking water treatment plant; therefore, further treatment of PFCs is needed to ensure our drinking water safety.
The removal of PFCs in wastewaters through advanced oxidation process were also investigated. Results demonstrated that ozonation and oxygen alone is ineffective. H2O2 and the H2O2/O3 were more effective in the overall treatment processes. When H2O2 or H2O2/O3 (17.1) ratio were added to the reaction tank, the PFOA, PFOS and PFDA were significantly removed. The slight increase of concentrations of these compounds was observed in the beginning of the treatment process; this may indicate the presence of other precursor compounds (higher carbon PFCs) later being degraded in the electronic plant effluents.
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