Hydrothermal synthesis of BiVO4 and its photocatalytic degradation of molasses fermentation wastewater under visible light irradiation
水热法制备BiVO4及其可见光催化降解糖蜜酒精废水

Using Bi(NO3)3 5H2O as bismuth source and NH4VO3 as vanadium source, BiVO4 photocatalysts were synthesized via a facile hydrothermal process and characterized using X-ray diffraction (XRD), scanning electronmicroscope (SEM), Infrared spectroscopy (IR) and UV-vis diffuse reflectance spectroscopy (UV-vis). The as-prepared products were used to photodegrade the molasses fermentation wastewater. The effects of BiVO4 dosage, air flow rate, pH values of wastewater, H2O2 dosage and the illumination intensity on the wastewater degradation were detailedly investigated. The results reveal that the as-prepared BiVO4 is of monoclinic structure with the band gap of 2.398 eV and exhibits an excellent visible-light photocatalytic activity. For the molasses fermentation wastewater with the initial pH value, when the flow rate of air is adjusted to 120 L h-1, the amount of added H2O2 is modulated at 9 %, and the concentration of BiVO4 is controlled to 3.0 g L 1, the decolorization ratio of the molasses fermentation wastewater diluted by distilled water for 30 times is 88.60 % and the COD remove ratio is 25.84% after irradiation by a 400W visible light for 180 min. Once the amount of FeSO4 7H2O with the conceration of 5 g L 1 was added, its decolorization ratio and COD remove ratio are increased to 90.90 % and 91.26 %, respectively. The photocatalyzed process of BiVO4 upon the molasses fermentation wastewater belongs to a first-order kinetic reaction.