Efficient decomposition of perfluorocarboxylic acids and alternative fluorochemical surfactants in hot water
Efficient decomposition of perfluorocarboxylic acids and alternative fluorochemical surfactants in hot water
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DOI：
10.1021/es800832p
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发表时间：
2008-10-01
影响因子：
11.4
通讯作者：
Kutsuna, Shuzo
中科院分区：
文献类型：
--
作者：
Hori, Hisao;Nagaoka, Yumiko;Kutsuna, Shuzo
研究了C5-C9全氟羧酸（PFCAs）和全氟醚羧酸（PFCA基表面活性剂的替代物）在热水中的热分解。虽然PFCAs在不存在过硫酸盐（S2 O 82-）的情况下在80 ℃的热水中几乎没有分解，但向反应体系中添加S2 O 82-导致有效的分解，即使在该相对较低的温度下。在水相和气相中的主要产物分别是F-离子和CO2，并且在水相中也检测到短链PFCAs。例如，当将含有全氟辛酸（PFOA，374 μ M）和S2 O 82-（50.0mM）的水溶液在80 ℃加热6小时时，水相中的PFOA浓度降至1.52 μ M以下（具有电导检测的HPLC的检测极限），并且F-离子的产率[即，（形成的F的摩尔数）/（初始PFOA中氟含量的摩尔数）]和CO2 [即，（形成的CO2的摩尔数）/（初始PFOA中碳含量的摩尔数）]分别为77.5%和70.2%。该方法还有效地分解全氟醚羧酸，如CF 3 OC 2F 4 OCF 2COOH、CF 3 OC 2F 4 OC 2F 4 OCF 2COOH和C2 F5 OC 2F 4 OCF 2COOH，它们是基于PFCA的表面活性剂的替代物，在80 ℃下反应6小时后，分别以82.9-88.9%和87.7- 100%的产率产生F-和CO2。此外，该方法被成功地用于分解地板蜡溶液中的全氟壬酸。当PFOA在较高温度（150摄氏度）下处理时，会发生其他分解反应：F-和CO2的形成急剧减少，并形成大量的1H-全氟烷烃（CnF 2n +1H，n = 4-7）。该结果清楚地表明，用高温水处理不适合于PFCAs分解为F-：令人惊讶的是，80 ° C的相对低的温度是优选的。
Decomposition Of C-5-C-9 perfluorocarboxylic acids (PFCAs) and perfluoroether carboxylic acids (alternatives to PFCA-based surfactants) in hot water in a sealed reactor was investigated. Although PFCAs showed almost no decomposition in hot water at 80 degrees C in the absence of persulfate (S2O82-), the addition Of S2O82- to the reaction system led to efficient decomposition, even at this relatively low temperature. The major products in the aqueous and gas phases were F- ions and CO2, respectively, and short-chain PFCAs were also detected in the aqueous phase. For example, when an aqueous solution containing perfluorooctanoic acid (PFOA, 374 mu M) and S2O82- (50.0 mM) was heated at 80 degrees C for 6 h, PFOA concentration in the aqueous phase fell below 1.52 mu M (detection limit of HPLC with conductometric detection), and the yields of F- ions [i.e., (moles of F- formed)/(moles of fluorine content in initial PFOA)] and CO2 [i.e, (moles Of CO2 formed)/(moles of carbon content in initial PFOA)] were 77.5% and 70.2%, respectively. This method was also effective in decomposing perfluoroether carboxylic acids, such as CF3OC2F4OCF2COOH, CF3OC2F4OC2F4OCF2COOH, and C2F5OC2F4OCF2COOH, which are alternatives to PFCA-based surfactants, producing F- and CO2 with yields of 82.9-88.9% and 87.7-100%, respectively, after reactions at 80 degrees C for 6 h. In addition, the method was successfully used to decompose perfluorononanoic acid in a floor wax solution. When PFOA was treated at a higher temperature (150 degrees C) other decomposition reactions occurred: the formation of F- and CO2 was dramatically decreased, and 1H-perfluoroalkanes (CnF2n+1H, n = 4-7) formed in large amounts. This result clearly indicates that treatment with high-temperature water was not suitable for the decomposition of PFCAs to F-: surprisingly, the relatively low temperature of 80 degrees C was preferable.