Decomposition of Perfluorocarboxylic Acids in Aqueous Solution Using Persulfate at Ambient Temperatures

• Main Authors: Yi-Ling Lin, 林怡伶
• Other Authors: Shang-Lien Lo
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/92070296555558840164

碩士 === 國立臺灣大學 === 環境工程學研究所 === 99 === In this research, a treatment to decompose the persistant and bioaccumulative perfluorooctanoic acid (PFOA) in water with high concentration of persulfate (S2O82-) at ambient temperature was developed. Persulfate is an effective oxidant for PFOA degradation without using any activated technology, even at a room temperature. The objectives of this study were to investigate the influences of pH ( pH 2.5, 7, and 11) and the persulfate doses (50-200 mM) on decomposition of PFOA at 20, 30 and 40 °C. Half-lives of PFOA degradation at 20, 30, and 40 °C. were 330, 61.3, and 13.46 h, respectively. Based on the laboratory experiment results, PFOA is completely decomposed by persulfate to form shorter-chain of perfluorinated carboxylic acids (PFCAs) and fluoride ions, with defluorination efficiency reaching 97 % within 218 hours at 40 °C. When the reaction temperature is maintained at 20 °C, 65 % of PFOA is decomposed with 41 % defluorination efficiency after 865 hours of reaction. Experimental data can be well simulated with pseudo first-order kinetics as the PFOA degradation, and the rate constants are 0.002 h-1 at 20 °C, 0.011 h-1 at 30 °C, 0.052 h-1 at 40 °C. The solution temperature has a definite impact on the decomposition of PFOA by persulfate. Increasing system temperature resulted in a greater increase in PFOA degradation rates than lowering system temperature.