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Sonochemical Degradation of Perfluorooctane Sulfonate (PFOS) and Perfluorooctanoate (PFOA) in Groundwater: Kinetic Effects of Matrix Inorganics

Cheng, Jie and Vecitis, Chad D. and Park, Hyunwoong and Mader, Brian T. and Hoffmann, Michael R. (2010) Sonochemical Degradation of Perfluorooctane Sulfonate (PFOS) and Perfluorooctanoate (PFOA) in Groundwater: Kinetic Effects of Matrix Inorganics. Environmental Science and Technology, 44 (1). pp. 445-450. ISSN 0013-936X. https://resolver.caltech.edu/CaltechAUTHORS:20100202-112053909

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Abstract

Ultrasonic irradiation has been shown to effectively degrade perfluorinated chemicals (PFCs) such as perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) in aqueous solution. Reduced PFC sonochemical degradation rates in organic-rich groundwater taken from beneath a landfill, however, testify to the negative kinetic effects of the organic groundwater constituents. In this study, the PFOX (X = S or A) sonochemical degradation rates in a groundwater sample with organic concentrations about 10 times lower than those in the groundwater taken from beneath a landfill are found to be 29.7% and 20.5% lower, respectively, than the rates in Milli-Q water, suggesting that inorganic groundwater constituents also negatively affect PFC sonochemical kinetics. To determine the source of the groundwater matrix effects, we evaluate the effects of various inorganic species on PFOX sonochemical kinetics. Anions over the range of 1−10 mM show Hofmeister effects on the sonochemical degradation rates of PFOX, k_(ClO_4)^(−PFOX) > k_(NO_3)^(−PFOX) ~ k_(Cl^−)^(−PFOX) ≥ k_(MQ)^(−PFOX) > k_(HCO_3)^(−PFOX) ~ k_(SO_(4)^(2−)^(−PFOX). In contrast, common cations at 5 mM have negligible effects. Initial solution pH enhances the degradation rates of PFOX at 3, but has negligible effects over the range of 4 to 11. The observed inorganic effects on sonochemical kinetics are hypothesized to be due to ions’ partitioning to and interaction with the bubble−water interface. Finally, it is shown that the rate reduction in the groundwater in this study is primarily due to the presence of bicarbonate and thus can be fully rectified by pH adjustment prior to sonolysis.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1021/es902651gDOIArticle
http://pubs.acs.org/doi/abs/10.1021/es902651gPublisherArticle
ORCID:
AuthorORCID
Park, Hyunwoong0000-0002-4938-6907
Hoffmann, Michael R.0000-0001-6495-1946
Additional Information:© 2010 American Chemical Society. Received September 1, 2009. Revised manuscript received November 9, 2009. Accepted November 16, 2009. Publication Date (Web): December 1, 2009. We thank 3M for the financial support and Dr. Nathan Dalleska and the Caltech Environmental Analysis Center for technical assistance in sample analysis.
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3MUNSPECIFIED
Issue or Number:1
Record Number:CaltechAUTHORS:20100202-112053909
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20100202-112053909
Official Citation:Sonochemical Degradation of Perfluorooctane Sulfonate (PFOS) and Perfluorooctanoate (PFOA) in Groundwater: Kinetic Effects of Matrix Inorganics Jie Cheng, Chad D. Vecitis, Hyunwoong Park, Brian T. Mader, Michael R. Hoffmann Environmental Science & Technology 2010 44 (1), 445-450
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:17374
Collection:CaltechAUTHORS
Deposited By: Jason Perez
Deposited On:04 Feb 2010 16:48
Last Modified:09 Mar 2020 13:19

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