Enhanced charge separation and O2 activation over an anion-rich photocatalyst Ba3(BO3)(CO3)F for metronidazole removal in water

The wide occurrence of metronidazole (MNZ) in aquatic environment has aroused increasing concern to the potential adverse effects on human health. Combining different motifs into a photolytic material to achieve high photocatalytic efficiency is regarded as one of the main strategies during photocatalytic process. Herein, a triple anions contained photocatalyst , Ba 3 (BO 3 )(CO 3 )F (BBCF), exhibited excellent removal efficiency of MNZ (92.6%) in 15 min, which was 5.87 times higher than that of commercial P25. The excellent removal efficiency could be attributed to the strong electronegativity of the F − , and the π-conjugated triangles structure of (BO 3 ) 3− and (CO 3 ) 2− , which made BBCF facilitate the transport of photogenerated electrons, thus accelerating the accumulation of active h + . Meanwhile, the appropriate reduction potential of BBCF accounted for the outstanding productivity of O 2 – . h + and O 2 – were proved as the dominant reactive species for MNZ degradation. The degradation products were analyzed by LC-TOF-MS, and the toxicity of the intermediate was evaluated to be lower than that of parent MNZ molecule. Moreover, BBCF showed the universal application of degrading oxytetracycline (OTC), methylene blue (MB). Therefore, anion-rich BBCF catalyst with high catalytic activity has a potential application prospect for degrading harmful pollutants in practical water environment.