全氟辛酸
光催化
化学
水解
降级(电信)
羟基自由基
光化学
激进的
光降解
环境化学
催化作用
有机化学
计算机科学
电信
作者
Jiye Huang,Xi Wang,Zhaoqi Pan,Xukai Li,Ling Yu,Laisheng Li
标识
DOI:10.1016/j.cej.2016.03.116
摘要
Perfluorooctanoic acid (PFOA) could be efficiently degraded by the combined process of photocatalysis and ozonation, its degradation intermediates were fluoride ions and short-chain perfluorocarboxylic acids (PFCAs) including C6F13COOH, C5F11COOH, C4F9COOH, C3F7COOH and C2F5COOH. After 4 h reaction time, its degradation efficiency was 99.1% and defluorination ratio only reached to 44.3%. The degradation mechanism of PFOA by photocatalytic ozonation was proposed and found to be similar to Photo-Kolbe reaction: PFOA anion was degraded to produce PFOA radical by a direct electron transfer from its carboxyl group to photo-generated hole (h+). Then PFOA radical was decarboxylated to produce perfluoroheptyl radical, and then be oxidized to form C7F15OH by hydroxyl radical (OH) which was produced from ozone trapping photo-generated electron. Because of its thermal instability, C7F15OH would be converted to C6F13COF, which was further hydrolyzed to generate C6F13COO−. Therefore the combined process of photocatalysis and ozonation was efficient for PFOA degradation.
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