US EPA

1490073 

Journal Article 

Decomposition of perfluorocarboxylic acids (PFCAs) by heterogeneous photocatalysis in acidic aqueous medium 

Panchangam, SC; Lin, AY; Shaik, KL; Lin, CF 

2009 

Yes 

Chemosphere
ISSN: 0045-6535
EISSN: 1879-1298 

Elsevier 

77 

2 

242-248 

English 

19665756 

10.1016/j.chemosphere.2009.07.003 

WOS:000270609100014 

https://linkinghub.elsevier.com/retrieve/pii/S0045653509007802
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Decomposition of perfluorocarboxylic acids (PFCAs) is of prime importance since they are recognized as persistent organic pollutants and are widespread in the environment. PFCAs with longer carbon chain length are particularly of interest because of their noted recalcitrance, toxicity, and bioaccumulation. Here in this study, we demonstrate efficient decomposition of three important PFCAs such as perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA) by heterogeneous photocatalysis with TiO(2) as a photocatalyst in acidic aqueous solutions. The PFCAs were decomposed into shorter carbon chain length PFCAs and fluoride ions. Photoholes of excited TiO(2) generated upon UV-irradiation are found to be the oxidation sites for PFCAs. Therefore, creation and sustenance of these photoholes in the acidic aqueous medium has enhanced the decomposition of PFCAs. Heterogeneous photocatalytic treatment achieved more than 99% decomposition and 38% complete mineralization of PFOA in 7h. The decomposition of other PFCAs was as high as 99% with a defluorination efficiency of 38% for PFDA and 54% for PFNA. The presence of perchloric acid was found to enhance the decomposition by facilitating the ionization of PFCAs. The oxygen present in the medium served both as an oxidant and an electron acceptor. The mechanistic details of PFCA decomposition and their corresponding mineralization are elaborated. 

Perfluorodecanoic acid; Perfluorononanoic acid; Perfluorooctanoic acid; Photocatalysis; Mineralization; Perchloric acid