Sonochemically enhanced PFOS and PFOA bubble surface activity

COLL 114

Chad D. Vecitis, vecitis@caltech.edu1, Hyunwoong Park, hpark@caltech.edu1, Jie Cheng, jetcheng@caltech.edu1, Tammy Campbell1, Brian Mader, bmader@mmm.com2, and Michael R. Hoffmann, mrh@caltech.edu1. (1) Environmental Science and Engineering, California Institute of Technology, W. M. Keck Laboratories 138-78, 1200 E. California Blvd., Pasadena, CA 91125, (2) Environmental Research Laboratories, 3M Corporation, 3M Center, Building 260-05-N-17, Maplewood, MN 55144-1000
The perfluorinated surfactants, perfluorooctane sulfonate (PFOS) and perfluorooctanoate(PFOA) are recognized as widepsread and persistent in the environment as well as recalcitrant towards conventional water treatment technologies. Acoustic cavitation as driven by high-frequency ultrasound has been shown to mineralize dilute aqueous solutions of these perfluorinated chemicals. The effect of initial PFOS and PFOA concentration, 10 nM to 1 mM each, on the sonolytic rate of degradation was evaluated at 354 kHz and 150 W L-1. The initial concentrations of PFOS and PFOA determine the relative partitioning of the surfactants to the bubble-water interface controlling the rate of degradation. The concentration dependent kinetics follow a Langmuir-Hinshelwood mechanism; at low concentrations the interface is sparsely covered and the kinetics are adsorption controlled, at high concentrations the interface is saturated and the kinetics are pyrolytically controlled.
 

The Physical Chemistry of Environmental Interfaces
2:00 PM-5:20 PM, Monday, April 7, 2008 Morial Convention Center -- Rm. 225, Oral

Division of Colloid & Surface Chemistry

The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008