Removing lignin model pollutants with BiFeO₃-g-C₃N₄ compound as an efficient visible-light-heterogeneous Fenton-like...

BiFeO₃-g-C₃N₄ nanoscaled composite was prepared with a hydrothermal method and evaluated as a highly efficient photo-Fenton like catalyst under visible light irradiation. The BiFeO₃-g-C₃N₄ composite exhibited much stronger adsorption ability to lignin model pollutant (guaiacol) than that of BiFeO₃, which may be due to the higher specific surface area (BiFeO₃-g-C₃N₄: 35.59m²/g>BiFeO₃: 7.42m²/g) and the adsorption form of π-π stack between g-C₃N₄ and guaiacol. The composite exhibited excellent visible light-Fenton like catalysis activity, being influenced by the solution pH value and the proportions of BiFeO₃ and g-C₃N₄ nanosheets. Under optimal conditions with visible light irradiation, the BiFeO₃-g-C₃N₄ composite yielded fast degradation of guaiacol with an apparent rate constant of 0.0452min^-1, which were 5.21 and 6.80 folds of that achieved by using BiFeO₃ and the mixture of BiFeO₃ and g-C₃N₄ nanosheets, respectively. The significantly enhanced visible light-Fenton like catalytic properties of the BiFeO₃-g-C₃N₄ composite in comparison with that of BiFeO₃ was attributed to a large surface area, much increased adsorption capacity and the semiconductor coupling effect between BiFeO₃ and g-C₃N₄ in the composite.