Decomposition of perfluorooctanoic acid photocatalyzed by titanium dioxide: Chemical modification of the catalyst surface induced by fluoride ions

The degradation of perfluorooctanoic acid (PFOA) in water was investigated both as photolysis and photocatalysis by slurry titanium dioxide. Different surfactant concentrations, the catalyst nature and concentration as well as the irradiation power of the UV lamp were evaluated. The reactions were conducted using merely the natural dissolved oxygen (DO), in order to simulate conditions of non-enriched water, as industrially feasible. The photomineralization of PFOA was monitored by total organic carbon (TOC) analysis and ionic chromatography (IC). Finally, the photocatalytic powder was analyzed at different reaction times by X-ray photoelectron spectroscopy (XPS) and by X-ray powder diffraction (XRD) technique in order to study and interpret the catalyst deactivation phenomena occurred during the treatment. (C) 2013 Elsevier B.V. All rights reserved.