Preparation And Properties Of Vanadate Semiconductor Materials

Using semiconductor photocatalyst process to deal with pollutants is a kind of pollution control technology in recent years.It is considered to be a most promising method at environmental governance.Vanadate is a typical kind of semiconductor material.Because of the appropriate band structure,good chemical stability,effective use of solar energy and environment friendly,it has attracted the attention of more and more researchers and becomes a hotspot.In this paper Rb₃V₅O₁₄ and K₃V₅O₁₄ were prepared via solid phase method.At the same time,Bi VO₄/A₃V₅O₁₄?A=Rb?K?composite photocatalytic materials were synthesized.The relationships between the structure and photocatalytic performance and adsorptive property were studied.Research content and main conclusions are as follows:1.The influences of reaction temperature and time for the structure and morphology of Rb₃V₅O₁₄ and K₃V₅O₁₄ are studied.Rb₃V₅O₁₄ and K₃V₅O₁₄ are layer structure.And the impurity and high reaction temperature are not conducive to the formation of layer structure.Furthermore,reaction time has no significant impact o n structure and morphology of A₃V₅O₁₄?A=Rb?K?materials.2.Their removal rate in the visible light and adsorption rate in the dark were tested.The results show that the removal process of methylene blue?MB?includes visible light degradation function and a rapid adsorption process.In other words,it's a photocatalytic-adsorption synergy.In visible light of 75 min,the removal rates of MB are 86.61%for Rb₃V₅O₁₄ and 91.14%for K₃V₅O₁₄,respectively.The adsorption rates are 81.37%and 84.46%in the dark.The MB molecules can be adsorbed into the layers and further to embed into internal micro-channels of the crystal with respect to their shape and size,and it causes the obvious adsorption performance.Effects of catalyst quantity and the adsorption of different dyes were discussed.The MB can be adsorbed selectively by A₃V₅O₁₄ materials and the best dosage is 0.5 g/L.Adsorption kinetics results show the pseudo-first-order model for Rb₃V₅O₁₄ fitted the adsorption kinetics well and K₃V₅O₁₄ can be described by the pseudo-second-order model.Removal and adsorption of A₃V₅O₁₄?A=Rb?K?for MB have a good stability and can be recycled.3.A₃V₅O₁₄?A=Rb?K?was modified with Bi VO₄ and Bi VO₄/A₃V₅O₁₄?A=Rb?K?were prepared.The proportion of composite,the initial pH and H₂O₂ dosage were discussed.The best experimental conditions are concluded:composite proportion is20%,the initial solution pH=11 and 1 mL for the amount of H₂O₂.Under the optimal conditions,the removal rates of MB are 94.16%for Bi VO₄/Rb₃V₅O₁₄ and 96.71%for Bi VO₄/K₃V₅O₁₄.