The photoabatement of perfluorooctanoic acid in aqueous solution has been performed with a commercial nano-sized TiO2-based photocatalyst content of 0.66 g/L under an UV irradiation of 95 W/m2. PFOA degradation intermediates were investigated by HPLC-MS and 19F-NMR analysis. Evidences of a degradation mechanism based on two competitive pathways are discussed: photo-redox and β-scission pathways. Shorter perfluorinated carboxylic acids, C n F2n+1COOH (n = 1-6), as expected degradation intermediates, were identified and their concentration trends over time were determined. The apparent pseudo-first order kinetic constant expressed as rate of PFOA disappearance was also measured: k app 0.1296 h-1. The influence of fluoride ions on TiO2 surface was analyzed by XPS technique, revealing a surface modification that affects the performances of the catalyst.
Surface fluorination on TiO2 catalyst induced by photodegradation of perfluorooctanoic acid / S. Gatto, M. Sansotera, F. Persico, M. Gola, C. Pirola, W. Panzeri, W. Navarrini, C.L. Bianchi. - In: CATALYSIS TODAY. - ISSN 0920-5861. - 241:part A(2015 Mar 01), pp. 8-14. [10.1016/j.cattod.2014.04.031]
Surface fluorination on TiO2 catalyst induced by photodegradation of perfluorooctanoic acid
S. GattoPrimo
;C. Pirola;C.L. BianchiUltimo
2015
Abstract
The photoabatement of perfluorooctanoic acid in aqueous solution has been performed with a commercial nano-sized TiO2-based photocatalyst content of 0.66 g/L under an UV irradiation of 95 W/m2. PFOA degradation intermediates were investigated by HPLC-MS and 19F-NMR analysis. Evidences of a degradation mechanism based on two competitive pathways are discussed: photo-redox and β-scission pathways. Shorter perfluorinated carboxylic acids, C n F2n+1COOH (n = 1-6), as expected degradation intermediates, were identified and their concentration trends over time were determined. The apparent pseudo-first order kinetic constant expressed as rate of PFOA disappearance was also measured: k app 0.1296 h-1. The influence of fluoride ions on TiO2 surface was analyzed by XPS technique, revealing a surface modification that affects the performances of the catalyst.File | Dimensione | Formato | |
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