Preparation Of Y-doped Bi₂WO₆/Graphene Photocatalyst And Application In Photocatalytic Reactor

Nowadays,more and more synthetic reactive dyes are widely used,and large amounts of synthetic dyes are released into the natural environment every year.Due to its strong carcinogenic,mutagenic and other characteristics,it will cause serious harm to humans and aquatic ecosystems.Photocatalytic oxidation technology,as a new advanced energy-saving advanced oxidation technology,is widely used in organic wastewater treatment due to its advantages of using sunlight as energy source,no secondary pollution,and low cost and easy accessibility.In this dissertation,the rare earth element Y was used for ion doping of the Bi₂WO₆ catalyst,and the Y-Bi₂WO₆ catalyst was loaded with graphene.Through the photocatalytic degradation experiment and characterization test of the composite catalyst,the optimum doping ratio of rare earth element Y and graphene oxide was determined,and the photocatalytic reaction mechanism of the composite catalyst was explored.The composite catalyst was loaded with a sponge carrier phase and applied to subsequent photocatalytic reactor operation experiments.The experimental results obtained are as follows.1.Preparation of Y-Bi₂WO₆ catalyst and its photocatalytic properties.Y-Bi₂WO₆ catalyst with visible light catalytic activity was prepared by one-step hydrothermal synthesis method using rare earth element Y and Bi₂WO₆ catalyst for ion doping.Through the characterization test and analysis of the catalyst and the results of photocatalytic degradation experiments,the optimum doping ratio of rare earth element Y is 1.0%.Under this condition,the catalyst's efficiency of 20mg/L RhB degradation reaches 95.4%within 80min.And its photocatalytic degradation mechanism was analyzed.2.Preparation and photocatalytic properties of Y-Bi₂WO₆/G composite catalysts.Graphene oxide and Y-Bi₂WO₆ catalyst were immobilized and loaded by hydrothermal synthesis.Y-Bi₂WO₆/G composite catalyst was prepared by hydrothermal synthesis method.Through the photocatalytic degradation and characterization analysis of the catalyst,the optimum doping ratio of graphene oxide was 2.0%.Under this condition,the degradation efficiency of RhB at 50mg/L was98.7%within 160 min.And its photocatalytic degradation mechanism was analyzed.3.Preparation of sponge supported Y-Bi₂WO₆/G composite catalyst and its application in photocatalytic reactor.Sponge-supported Y-Bi₂WO₆/G composite catalyst was prepared by physical methods.The optimum operating conditions determined by photocatalytic reactor experiments were that the catalyst dosage was 5g/L,the initial contaminant concentration was 50mg/L,the hydraulic retention time was 6h,and the light intensity was 140,000lux.The supported catalyst has a degradation efficiency of more than 90%for 50mg/L RhB within 140min.At the same time,the supported catalyst has good stability in the application of photocatalytic reactor,and it can still ensure the good degradation efficiency of RhB after continuous operation for 72hours.