水热法制备BiVO4及其可见光催化降解糖蜜酒精废水

以Bi(NO3)3•5H2O为铋源，NH4VO3为钒源，采用简单的水热法制备了BiVO4 光催化剂，并用X-射线衍射(XRD)、扫描电子显微镜(SEM)、红外光谱(IR)和紫外-可见光漫反射光谱(UV-vis)对产品进行了结构表征。同时，在BiVO4光催化降解糖蜜酒精废水反应中考察了催化剂用量、通氧量、溶液pH值、双氧水用量及光照强度对糖蜜酒精废水脱色率的影响。实验结果表明，水热产品属于单斜晶系BiVO4，其带隙能为2.398 eV，并具有良好的可见光催化活性。当降解经30倍稀释的糖蜜酒精废水，BiVO4添加量为3.0 g•L−1 ，通氧量为120 L•h-1，助氧化剂H2O2添加量为9 %，不改变废水pH值，在400W镝灯离液面11cm照射反应180 min的条件下，糖蜜酒精废水的脱色率为88.60 %，COD去除率为25.84%，而添加5g•L−1的FeSO4•7H2O后其脱色率和COD去除率分别提高到90.90 %和91.26%。单斜晶型BiVO4晶体的可见光催化糖蜜酒精废水过程符合一级动力学反应。

Hydrothermal synthesis of BiVO4 and its photocatalytic degradation of molasses fermentation wastewater under visible light irradiation

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.