Decomposition of perfluorooctanoic acid by ultraviolet light irradiation with Pb-modified titanium dioxide.

Perfluorooctanoic acid (PFOA, C7H15COOH) is widely used in industrial and commercial applications. It has become a global concern due to its widespread occurrence in water bodies and adverse environmental impact. PFOA could not be effectively removed by the conventional UV/TiO2 system. This study synthesized Pb-modified TiO2 catalyst and used it as a catalyst with light irradiation for PFOA decomposition. It was found that the Pb-TiO2 catalyst could produce traps to capture photo-induced electrons or holes that lead to better photocatalytic efficiencies. Rate constant values for PFOA decomposition by the UV/TiO2 and UV/Pb-TiO2 systems were determined to be 0.0158 and 0.5136 h(-1), respectively. The PFOA decomposition in the UV/Pb-TiO2 system is 32.5 times faster than that in the UV/TiO2 system. The UV/Pb-TiO2 system yielded a better performance than those of the UV/Fe-TiO2 and UV/Cu-TiO2 systems. During the reaction, PFOA decomposed stepwisely into shorter-chain perfluorocarboxylic acids and F(-).