Efficient Photocatalytic Decomposition of Perfluorooctanoic Acid by Indium Oxide and Its Mechanism

Citations Over TimeTop 1% of 2012 papers

Abstract

Perfluorooctanoic acid (C(7)F(15)COOH, PFOA) has increasingly attracted worldwide concerns due to its global occurrence and resistance to most conventional treatment processes. Though TiO(2)-based photocatalysis is strong enough to decompose most organics, it is not effective for PFOA decomposition. We first find that indium oxide (In(2)O(3)) possesses significant activity for PFOA decomposition under UV irradiation, with the rate constant about 8.4 times higher than that by TiO(2). The major intermediates of PFOA were C(2)-C(7) shorter-chain perfluorocarboxylic acids, implying that the reaction proceeded in a stepwise manner. By using diffuse reflectance infrared Fourier transform spectroscopy, (19)F magic angle spinning nuclear magnetic resonance, and electron spin resonance, we demonstrate that the terminal carboxylate group of PFOA molecule tightly coordinates to the In(2)O(3) surface in a bidentate or bridging configuration, which is beneficial for PFOA to be directly decomposed by photogenerated holes of In(2)O(3) under UV irradiation, while PFOA coordinates to TiO(2) in a monodentate mode, and photogenerated holes of TiO(2) preferentially transform to hydroxyl radicals, which are inert to react with PFOA. PFOA decomposition in wastewater was inhibited by bicarbonate and other organic matters; however, their adverse impacts can be mostly avoided via pH adjustment and ozone addition.

Related Papers

• → Perfluorinated compounds in soil, surface water, and groundwater from rural areas in eastern China(2015)219 cited
• → Perfluorooctanoic acid (PFOA) exposure in relation to the kidneys: A review of current available literature(2023)48 cited
• → Perfluorooctanoic Acid-Disturbed Serum and Liver Lipidome in C57BL/6 Mice(2022)7 cited
• → Dietary exposure to perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS): a review of recent literature(2017)24 cited
• Elimination of Perfluorooctanoic Acid Emulsifier(2007)