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Sonochemical Destruction of Persistent Organic Pollutants

Speaker: Chad Vecitis, Graduate Student, California Institute of Technology, Pasadena, CAAbstractPerfluorinated chemicals are recognized as widespread in the environment and are bio-accumulative, persistent, and recalcitrant towards conventional treatment technologies. Acoustic cavitation as driven by high-frequency ultrasound can be employed for the remediation of dilute, aqueous perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) solutions. Complete sonochemical conversion of PFOS and PFOA to their inorganic constituents; CO, CO2, SO42- and F-, occurs shortly after the initial pyrolytic reaction at the surface of cavitating bubbles. PFOS and PFOA concentration-dependent sonochemical degradation kinetics are correlated to their initial concentrations which determine relative partitioning to the bubble-water interface and are modeled well by saturation kinetics. Maximum degradation rates were obtained at an ultrasonic frequency of 350 kHz where the rate of degradation is observed to increase with increasing power density. Landfill leachate and groundwater matrices were determined to have negative effects on sonochemical PFOX destruction kinetics. The major chemical factors such as co-contaminants, NOM and bicarbonate as well as possible solutions were evaluated.

Location: Kaprielian Hall (KAP) - 209

Audiences: Everyone Is Invited

Contact: Evangeline Reyes