Photocatalytic Oxidation Of Biomass Derivatives To Prepare High Value-added Chemicals

With the development of economy and society,the more consumption of fossil fuels has lead to the environmental pollution and energy shortage which have become two major problems that need to be solved urgently in the world.Biomass,a renewable and abundant resource,can be transformed into a variety of energy products.It was promising resource and has attracted more and more attention.Glycerol and glucose,as the main biomass derivatives,can be converted into high-value-added chemicals by photocatalysis.It is significant for the usage and development of biomass resource.Semiconductor materials are commonly used in photocatalytic technology.Bi₂WO₆has the advantages of simple preparation,low cost,environmental friendliness and stable chemical properties.In recent years,it has received extensive attention and is often used in photocatalytic degradation of organic pollutants,hydrogen production by photolysis of water and photocatalytic organic synthesis.Graphite carbon nitride is a non-metal semiconductor material with abundant reserves,cheap and easy-to-obtain raw materials,and non-toxic and harmless.The band gap was 2.7 e V and it can respond to ultraviolet light and part of visible light.Moreover,it is resistant to light corrosion.It is often used for hydrogen production by photolysis of water,degradation of organic pollutants and photocatalytic reforming.Therefore,in this study,Bi₂WO₆and g-C₃N₄were used as photocatalysts to study the photocatalytic oxidation of glycerol and glucose.In this work,firstly,Bi?NO₃?₃·5H₂O and Na₂WO₄·2H₂O were used as precursors to prepare nano-flower-like Bi₂WO₆by hydrothermal method.The crystal structure and morphology,optical properties and electrochemical properties were characterized by various equipments.Then the experiments about photocatalytic oxidation of biomass derivatives?glycerol and glucose?were carried out.The effect of illumination time,catalyst concentration and photocurrent on photocatalysis process were studied by designing orthogonal experiments.The Gas Chromatography-Mass Spectrometer?GC-MS?was used to qualitatively analyst reaction products.The High Performance Liquid Chromatography?HPLC?was adopted to quantitatively analyst reaction products.The best photocatalytic conditions were obtained by analysting and comparing the experimental results.The results of Bi₂WO₆photocatalytic oxidation of glycerol is better than that of glucose,and the glycerol conversion rate reaches65.00%under the optimal experimental conditions.Secondly,using cyanamide as the precursor and colloidal SiO₂as the hard template,g-C₃N₄with hierarchical structure was synthesized.The crystal structure and morphology,optical properties and electrochemical properties were characterized by various equipments.The experiments about photocatalytic oxidation of biomass derivatives?glycerol and glucose?were carried out.The effect of illumination time,catalyst concentration and photocurrent on photocatalysis process were studied by designing orthogonal experiments.The GC-MS was used to qualitatively analyst reaction products.The HPLC was adopted to quantitatively analyst reaction products.The best photocatalytic conditions were obtained by analysting and comparing the experimental results.The results of g-C₃N₄photocatalytic oxidation of glucose is better than that of Bi₂WO₆photocatalytic oxidation,and the glucose conversion rate reaches 49.09%under the optimal experimental conditions.