Synthesis Of Highly-efficient VS₄ Photocatalyst And Applications In Treatment And Resue Of Dyeing Wastewater

Photocatalytic reaction is a new,efficient,safe,economical and environment-friendly environment-purifying technique,which uses light energy to drive photocatalyst for photocatalytic reaction.In this process,strong oxidation capacity reactive species can degrade dye molecules in dyeing wastewater and inactivate microorganisms like bacteria.Owing to many semiconductor photocatalysts have wide band gaps,they can only react under ultraviolet light,which limites the wide application of them.Developing efficient photocatalyst activating photocatalytic reaction under visible light is urgently required.Firstly,VS₄/carbon powder photocatalyst（VS₄/CP）was synthesized by one step hydrothermal synthesis in the present study.The physical characterizations showed that VS₄/carbon powder was nanomaterial,pure and and had good dispersibility.The decolorization efficiency of methyl orange was 98.8±0.9%under simulated visible light irradiation.Reactive species such as·O₂^-,e^-and h⁺played important roles in the photocatalytic decolorization.Compared with other semiconductor photocatalysts,VS4/carbon powder had advantages of short reaction time,higher decolorization efficiency per unit mass catalyst,and it also had better stability and reusability.Secondly,the VS₄/CP photocatalyst was used to carry out the photocatalytic disinfection under the simulated visible light.The results showed that the VS₄/CP photocatalyst had 7.7 log photocatalytic inactivation efficiency of Escherichia coli,but the inhibitory ability of Staphylococcus aureus was general.Compared with the other photocatalyst,the VS₄/CP photocatalyst had a higher inactivation efficiency and less dosage,it could maintain the high inactivation efficiency of Escherichia coli in four consecutive reused cycles.The main bacterial inactivation mechanism may be determined by membrane damage and penetration-induced intracellular damage.Reactive species such as·O₂^-,e^-and h⁺played important roles in the process of photocatalytic disinfection.Finally,four different carbon materials were used as photocatalyst support and their co-catalysis effects were investigated.The result of physical characterizations revealed that the four carbon carriers had better dispersibility and higher specific surface area than VS_x without support.The result of photocatalytic decolorization and disinfection showed that four carbon carrier catalysts had good photocatalytic properties and the co-catalysis effect in descending order was:reduced graphene oxide>carbon powder>carbon nanotube>carbon fibre.These results was helpful to further improve the properties of VS₄ photocatalyst.In conclusion,VS₄/CP nanocomposites with excellent photocatalytic properties was developed and their feasibility of application in dyeing wastewater treatment and resue was established.Results from this study also provided theoretical support for its practical applications in other wastewater treatments.