Factors influencing UV photodecomposition of perfluorooctanoic acid in water

Giri, Rabindra Raj; Ozaki, Hiroaki; Okada, T.; Taniguchi, Shigeji; Takanami, Ryohei

doi:10.1016/j.cej.2011.11.049

Cited by 78 publications

(69 citation statements)

References 27 publications

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“…The linearization of PFOA degradation data are reported in Figure 1 (Fig.1-B in accordance to the literature [24]. The absence of any PFOA abatement in the dark test confirmed also that PFOA adsorption on the TiO 2 surface was negligible.…”

supporting

confidence: 72%

The effect of oxygen in the photocatalytic oxidation pathways of perfluorooctanoic acid

Sansotera

Persico

Rizzi

et al. 2015

Journal of Fluorine Chemistry

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supporting

confidence: 72%

The effect of oxygen in the photocatalytic oxidation pathways of perfluorooctanoic acid

Sansotera

Persico

Rizzi

et al. 2015

Journal of Fluorine Chemistry

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“…Furthermore, it is not yet known what would happen with PFOA degradation and defluorination efficiencies if VUV (185 nm) is used in photoreductive reaction conditions. The first-order rate value for photoreductive degradation of PFOA with aquated electrons (7.3 9 10 -3 min -1 ; Qu et al 2010) and a roughly estimated first-order PFOA photolysis rate value (10.2 9 10 -3 min -1 ; Giri et al 2011Giri et al , 2012 with VUV (185 nm) indicate that photoreductive degradation of PFOA with VUV could be significantly slower than its VUV photolysis degradation. However, this point has not yet been experimentally verified.…”

Section: Introductionmentioning

confidence: 99%

“…Although direct UVC (254 nm) photolytic degradation of PFOA is negligibly small (Chen et al 2007;Giri et al 2011), use of chemical oxidants together with UVC can decompose the compound more easily (Chen and Zhang 2006;Wang et al 2008;Cao et al 2010;Tang et al 2012). Furthermore, it has been demonstrated during the last few years that vacuum UV (VUV) (185 nm) photolysis is more efficient than other VU-based methods for PFOA degradation (Chen et al 2007;Giri et al 2011Giri et al , 2012. The carbon-carbon bond in carboxyl functional group is cleaved first followed by formation of fluoride ions due to hydrolysis in stepwise manner during UV oxidation of PFOA and other shorter carbon-chain perfluoroalkyl carboxylates as illustrated in the following equations (Chen et al 2007):…”

Section: Introductionmentioning

confidence: 99%

Oxidative–reductive photodecomposition of perfluorooctanoic acid in water

Giri

Ozaki

Guo

et al. 2013

Int. J. Environ. Sci. Technol.

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This article aims to elucidate on usefulness of vacuum ultraviolet (VUV) for photoreductive degradation of perfluorooctanoic acid (PFOA), a representative perfluorinated compound (PFC), in water for the first time. Bench-scale tests were conducted on oxidative and reductive (with aquated electron: e aq -) mineralization of PFOA using low-pressure UV (LPUV) lamps and potassium iodide. Unlike with 254 nm wavelength (UVC), the reductive mineralization with VUV was very inefficient compared to the corresponding oxidative mineralization. The inefficiency is attributed to low reactivity of e aq -with PFOA and its fluorinated products than that of 185 nm photons. Direct VUV photolysis of PFOA and its products in reductive reaction conditions was not apparent due to a very big difference in reactivity of 185 and 254 nm photons with iodide. The results demonstrated that highly energetic VUV photons are not suitable for photoreductive degradations of PFCs involving e aq -, but they can be best used for oxidative degradations. These findings should serve as an important reference on VUV usage to decompose refractory micropollutants.

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“…As shown in Figure 6, PFOS with an initial concentration of 2 M decomposed much faster under both UV 254 and UV 254+185 irradiation, and the corresponding rate constants were increased to 1.45 d , respectively. As the UV light intensity directed at the reaction solution was constant, a photonlimited condition may occur in the reactor in the case of relatively higher PFOS concentration, resulting in a slower PFOS decomposition (Giri et al, 2012).…”

Section: Effect Of Water Quality and Initial Pfos Concentrationmentioning

confidence: 99%

Factors Influencing the Ferric Ion-mediated Photochemical Decomposition of Perfluorooctane Sulfonate (PFOS) in Water

Jin

Zhang

Shao

2015

Journal of Advanced Oxidation Technologies

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Abstract:Perfluorooctane sulfonate (PFOS) has received increasing attention due to its persistence in the environment, accumulation and global occurrence. The enhancement of the photochemical oxidative degradation of perfluorooctane sulfonate upon addition of ferric ions under 254-nm UV and 185-nm vacuum UV (VUV) light was observed for the first time. In the presence of ferric ions (100μM) and at pH 3.0, 85.3% of the initial PFOS (20 μM) was decomposed, with the rate constant of 1.92 d -1, and the defluorination ratio reached 47.5% within 24 h under 254-nm UV irradiation. The influences of the ferric ion concentration, the solution pH and the UV wavelength on the PFOS photodecomposition were investigated. In addition, the photochemical decomposition of PFOS in the secondary effluent from a municipal wastewater plant was investigated. The coexisting organic matter in the secondary effluent greatly reduced the PFOS decomposition rate to less than 1/3 of that in pure water under 254-nm UV irradiation. However, under 185-nm VUV light the coexisting organic matter could be quickly degraded, and accordingly their adverse impacts could be largely eliminated. Moreover, the influences of initial PFOS concentration in the secondary effluent was examined under UV 254 or UV 254+185 light in the presence of ferric ions (100μM), PFOS at a lower concentration (2 μM) decomposed much faster than that at a higher concentration (20 μM), and its decomposition intermediates, i.e., C2-C7 perfluorinated carboxylic acids, could also be decomposed and mineralized.

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Factors influencing UV photodecomposition of perfluorooctanoic acid in water

Cited by 78 publications

References 27 publications

The effect of oxygen in the photocatalytic oxidation pathways of perfluorooctanoic acid

The effect of oxygen in the photocatalytic oxidation pathways of perfluorooctanoic acid

Oxidative–reductive photodecomposition of perfluorooctanoic acid in water

Factors Influencing the Ferric Ion-mediated Photochemical Decomposition of Perfluorooctane Sulfonate (PFOS) in Water

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