Degradation of Perfluorooctanoic Acid (PFOA) by Reactive Species Generated through Catalyzed Hydrogen Peroxide Propagation Reactions(ABSTRACT)

摘要

Perfluorinated compounds (PFCs) are emerging contaminants of increasing environmental and public health concern because of their persistence and bioaccumulation. Perfluorooctanoic acid (PFOA) is a typical PFC used by industry in surfactants, fire retardants, high temperature lubricants, and as a polymer additive for the production of Teflon. The diverse industrial applications of PFCs are related to the unique physicochemical properties of the strong carbon-fluorine (C-F) bond, which creates a thermally stable compound. Numerous treatment technologies including photocatalytic oxidation, photolysis, photochemical reduction, sonochemical pyrolysis, and granular activated carbon filtration have been investigated for PFOA degradation, but none are highly effective. Hydroxyl radical (OH.), which is usually effective in oxidizing saturated and unsaturated carbon bonds in organic pollutants, is ineffective for degrading PFOA (k_(OH·+PFOA) ≤ 10~5 L.mol~(-1)·s~(-1)). Modified Fenton's reagent or catalyzed H2O2 propagation is based on the catalyzed decomposition of hydrogen peroxide by soluble iron, iron chelates, or iron minerals to generate the strong oxidant OH·, as well as other reactive species such as perhydroxyl radical (HO_2~-), superoxide radical anion (O_2~(-·)), and hydroperoxide anion (HO_2~-) through propagation reactions. Some of these species function as reductants and nucleophiles (O_2~(-.) and HO_2~-), and may have the potential to degrade PFCs. The purpose of this research was to investigate the effectiveness of CHP for degrading PFOA, and if effective, the reactive oxygen species responsible for its degradation.