Photocatalytic Degradation of Perfluorooctanoic Acid (PFOA) From Wastewaters by TiO2, In2O3 and Ga2O3 Catalysts

The aim of the work was to prepare nanosized In2O3 and Ga2O3 photocatalysts for degradation of perfluorooctanoic acid (PFOA) in water. Their commercial references along with TiO2 were used as a comparison basis. The characterization of the materials proved that successful preparation of cubic In2O3 and monoclinic beta-Ga2O3 were achieved via solvothermal and hydrothermal methods, respectively. The effect of different parameters such as catalyst dosage, UV light source and utilization of inorganic oxidant in PFOA treatment were evaluated. In2O3, photocatalyst was the most efficient in the degradation of 15 mg L-1 PFOA under UVB irradiation and synthetic air reaching 27% of degradation, which was 20 percentage points higher than for commercial In2O3. This is proposed to be partly due to significantly higher specific surface area of the self-made In2O3 and smaller crystallite size and partly due to more efficient absorption of UVB light compared to the other tested materials. Addition of KBrO3 did not improve the activity of self-made In2O3.