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Enhancement of perfluorooctanoate and perfluorooctanesulfonate activity at acoustic cavitation bubble interfaces

Vecitis, C. D. and Park, H. and Cheng, J. and Mader, B. T. and Hoffmann, M. R. (2008) Enhancement of perfluorooctanoate and perfluorooctanesulfonate activity at acoustic cavitation bubble interfaces. Journal of Physical Chemistry C, 112 (43). pp. 16850-16857. ISSN 1932-7447. https://resolver.caltech.edu/CaltechAUTHORS:20090507-100656322

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Abstract

Acoustic cavitation driven by ultrasonic irradiation decomposes and mineralizes the recalcitrant perfluorinated surfactants perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA). Pyrolytic cleavage of the ionic headgroup is the rate-determining step. In this study, we examine the sonochemical adsorption of PFOX, where X = S for PFOS and A for PFOA, by determining kinetic order and absolute rates over an initial PFOX concentration range of 20 nM to 200 μM. Sonochemical PFOX kinetics transition from pseudo-first-order at low initial concentrations, [PFOX]_i < 20 μM to zero-order kinetics at high initial concentrations, [PFOX]_i > 40 μM, as the bubble interface sites are saturated. At PFOX concentrations below 100 μM, concentration-dependent rates were modeled with Langmuir−Hinshelwood (LH) kinetics. Empirically determined rate maximums, V_(Max)^(−PFOA) = 2230 ± 560 nM min^−1 and V_(Max)^(−PFOS) = 230 ± 60 nM min^−1, were used in the LH model, and sonochemical surface activities were estimated to be K_(Sono)^(PFOS) = 120000 M^−1 and K_(Sono)^(PFOA) = 28500 M^−1, 60 and 80 times greater than equilibrium surface activities, K_(Eq)^(PFOS) and K_(Eq)^(PFOA). These results suggest enhanced sonochemical degradation rates for PFOX when the bubble interface is undersaturated. The present results are compared to previously reported sonochemical kinetics of nonvolatile surfactants.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1021/jp804050pDOIArticle
http://pubs.acs.org/doi/full/10.1021/jp804050pPublisherArticle
ORCID:
AuthorORCID
Park, H.0000-0002-4938-6907
Hoffmann, M. R.0000-0001-6495-1946
Additional Information:© 2008 American Chemical Society. Received: November 9, 2007; Revised Manuscript Received: August 7, 2008. We would like to thank the 3M Company for research support. This support included the donation to Caltech of analytical standards and an Agilent LC-MS-Ion Trap mass spectrometer. The authors also thank Dr. Nathan Dalleska of the Environmental Analytical Center.
Issue or Number:43
Record Number:CaltechAUTHORS:20090507-100656322
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20090507-100656322
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:14178
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:11 May 2009 21:39
Last Modified:09 Mar 2020 13:19

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