Cheng, Jie and Vecitis, Chad D. and Park, Hyunwoong and Mader, Brian T. and Hoffmann, Michael R. (2008) Sonochemical Degradation of Perfluorooctane Sulfonate (PFOS) and Perfluorooctanoate (PFOA) in Landfill Groundwater: Environmental Matrix Effects. Environmental Science and Technology, 42 (21). pp. 8057-8063. ISSN 0013-936X http://resolver.caltech.edu/CaltechAUTHORS:CHEest08
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Perfluorinated chemicals such as perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) are environmentally persistent and recalcitrant to most conventional chemical and microbial treatment technologies. In this paper, we show that sonolysis is able to decompose PFOS and PFOA present in groundwater beneath a landfill. However, the pseudo first-order rate constant for the sonochemical degradation in the landfill groundwater is reduced by 61 and 56% relative to MilliQ water for PFOS and PFOA, respectively, primarily due to the presence of other organic constituents. In this study, we evaluate the effect of various organic compounds on the sonochemical decomposition rates of PFOS and PFOA. Organic components in environmental matrices may reduce the sonochemical degradation rates of PFOS and PFOA by competitive adsorption onto the bubble−water interface or by lowering the average interfacial temperatures during transient bubble collapse events. The effect of individual organic compounds depends on the Langmuir adsorption constant, the Henry’s law constant, the specific heat capacity, and the overall endothermic heat of dissociation. Volatile organic compounds (VOCs) are identified as the primary cause of the sonochemical rate reduction for PFOS and PFOA in landfill groundwater, whereas the effect of dissolved natural organic matter (DOM) is not significant. Finally, a combined process of ozonation and sonolysis is shown to substantially recover the rate loss for PFOS and PFOA in landfill groundwater.
|Additional Information:||Copyright © 2008 American Chemical Society. Received May 19, 2008. Revised manuscript received July 18, 2008. Accepted August 7, 2008. Publication Date (Web): September 23, 2008. We thank 3M for the financial support and the Caltech Environmental Analysis Center (Dr. Nathan Dalleska) for technical assistance in sample analysis. Supporting Information Available: (1) Sonochemical degradation kinetics of PFOS and PFOA in landfill groundwater vs MilliQ at 612 kHz. (2) Sonochemical degradation kinetics of PFOS and PFOA under argon vs oxygen vs ozone. (3) Temperature dependence of Kiaw’s and Cp,g’s for the five organic compounds in Table 2. (4) Calibration and quality control results for the LC-MS analysis of PFOS and PFOA. This material is available free of charge via the Internet at http://pubs.acs.org.|
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|Deposited On:||19 Dec 2008 04:13|
|Last Modified:||26 Dec 2012 10:38|
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