Research Perfluorinated Bitter Water Nanometer Gallium Photocatalytic Oxidation Degradation

Perfluorooctanoic acid （PFOA） is an emerging persistent organic pollutant andreceives increasing concerns due to its global occurrence and toxic and carcinogeniceffects on human health. PFOA is resistant to most conventional decompositionmethods. This study develops routes to synthesize morphologically controllable Ga₂O₃photocatalysts via a solution synthesis approach, and the heterogeneous photocatalyticdecomposition of PFOA by nanostructured Ga₂O₃was investigated. The main resultsare concluded as follows.The nanostructured-Ga₂O₃with sheaf-like structure or needle-like structure wassynthesized via a PVA-assisted hydrothermal method and subsequent heat treatment.The sheaf-like Ga₂O₃possessed a high value of specific surface area （36.1m2/g） and alarge number of nanopores （2-4nm and8nm）. The needle-like β-Ga₂O₃also possessedlarge specific surface area of25.95m2/g and nanopores between4nm and25nm.The sheaf-like Ga₂O₃and needle-like Ga₂O₃exhibited remarkable photocatalyticactivity for PFOA decomposition in pure water under254nm UV irradiation. Thedegradation rate constant of PFOA by the sheaf-like Ga₂O₃was4.85h^-1, which was16and44times higher than that of commercial Ga₂O₃and Degussa P25respectively. Therate constant of PFOA by the needle-like Ga₂O₃was also high (2.28h^-1). This can beattributed to the close bonding of PFOA to the Ga₂O₃surface in a bidentate or bridgingconfiguration mode, and the nanoporous structure of sheaf-like Ga₂O₃. In addition, incombination of185nm vacuum UV irradiation, the sheaf-like Ga₂O₃and needle-likeGa₂O₃showed high efficiency to remove trace PFOA in the secondary effluent ofsewage, in which the decomposition of targeted trace pollutants such as PFOA isgenerally inhibited by coexisting high-level natural organic matters and bicarbonate.The corresponding energy consumption for PFOA decomposition by the sheaf-like orneedle-like Ga₂O₃photocatalysis is far below the values reported in literatures.