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Surface fluorination on TiO2 catalyst induced by photodegradation of perfluorooctanoic acid

Paper ID Volume ID Publish Year Pages File Format Full-Text
54480 47011 2015 7 PDF Available
Title
Surface fluorination on TiO2 catalyst induced by photodegradation of perfluorooctanoic acid
Abstract

•Photoabatement of PFOA solutions with TiO2 slurry.•HPLC–MS analysis to determine the intermediates of PFOA degradation.•XPS analyses of TiO2 to monitor surface variations induced by fluoride ions.

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, CnF2n+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: kapp 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.

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Keywords
Titanium dioxide; PFOA; Photocatalysis; Pollution; HPLC–MS; 19F-NMR
First Page Preview
Surface fluorination on TiO2 catalyst induced by photodegradation of perfluorooctanoic acid
Publisher
Database: Elsevier - ScienceDirect
Journal: Catalysis Today - Volume 241, Part A, 1 March 2015, Pages 8–14
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis