Y. S. Kim, HL Teslow, Jun-Woo Park, LA Rosocha, HW Herrmann

CF4/O-2/He reaction chemistry in an atmospheric pressure plasma jet

Journal of Advanced Oxidation Technologies 8 (2005) 182-187

An atmospheric pressure plasma jet (APPJ) operated with a CF4/O-2/He gas mixture has recently been demonstrated to decontaminate actinide materials such as plutonium and uranium. However, a comprehensive study of the chemical kinetics for an atmospheric plasma containing CF4/O-2/He does not exist. To understand and optimize the decontamination process, ultraviolet (UV) absorption spectroscopy was employed to measure chemically active species, such as dioxygen fluoride (O2F) and ozone (O-3), inside and outside the APPJ. At room temperature operation, O2F was found to be a significant long-lived radical, which lasted up to 10 ms in the effluent with a density of about 10(15) cm(-3). The concentration of O-3 does not fall off and keeps its density constant up to 10 ms, which indicates the absence of atomic fluorine (F) outside the APPJ. Measurements were in good agreement with a gas-phase post-plasma simulation. In summary, atomic fluorine produced inside the APPJ recombines with O-2 molecules, producing O2F molecules, which can live long enough to etch metal surfaces.

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