Research On Photocatalysis And Intelligent Prediction Technology Of Magnesium Aluminate Surface Modified Noble Metal Particle

With the development of industrialization,human production activities have caused serious pollution to the water quality.The sewage discharged after the production of printing and dyeing,paper making and textile has reached hundreds of tons.Scientific researchers all over the world deal with the water pollution through various methods,and photocatalytic technology as a“green technology”to achieve the degradation of sewage treatment.MgAl₂O₄is a kind of semiconductor material can be used as a good photocatalyst in the field of photocatalysis due to it’s non-toxic and harmless,good stability,high heat resistance and corrosion resistance and other excellent properties.In this thesis,the polyacrylamide gel method was used to regulate and synthesis of MgAl₂O₄based materials to explore its adsorption characteristics and photocatalytic activities.The influences of different parameters on the physical and chemical properties of MgAl₂O₄based materials were investigated and a model was built based on neural network algorithm to predict its physical and chemical properties.Based on the experimental results and mechanism analysis,the adsorption capacity of MgAl₂O₄based materials were explored,the internal adsorption mechanism and photocatalytic mechanism were explained,and the internal correlation mechanism between the adsorption and photocatalysis was revealed.The specific research contents were as follows:（1）The polyacrylamide gel method is used to regulate and synthesis of MgAl₂O₄nanoparticles with different sizes,and the size of MgAl₂O₄nanoparticles can be effectively adjusted by adjusting different metal sources.The crystal structure,phase purity,morphology,charge state,pore size and adsorption capacity of MgAl₂O₄nanoparticles were studied by various characterization methods.The results show that MgAl₂O₄has excellent adsorption capacity for the adsorption of Congo red dye.Based on BP neural network algorithm,the phase purity experiment of MgAl₂O₄material was simulated and predicted by Matlab/python software.The results are consistent with the characterization results,which can be used as guidance for the preparation of the adsorbents.（2）The MgAl₂O₄based composites with different carbon sources were constructed by the ultrasonic-assisted method.The phase structure,surface morphology,elemental composition,electron energy level and adsorption capacity of carbon source（AC,C₃N₄,CQDs,GO）-MgAl₂O₄composites were studied by different characterization methods.With the composite of different carbon sources,the optimal composite ratio was determined,and the high concentration adsorption of Congo red and the selective adsorption of several antibiotic drugs were carried out at different concentrations,different catalyst loads,different p H and different temperatures.The p H_pzcof each carbon-based MgAl₂O₄composites was obtained by experiments.Based on microscopic observation and calculation combined with different models,a reasonable adsorption mechanism of carbon based-MgAl₂O₄adsorbents for the adsorption of Congo red and antibiotic was proposed.（3）The Au-C₃N₄-MgAl₂O₄heterojunction photocatalysts with different mass ratios were constructed by the polyacrylamide gel method,photoreduction method and low temperature sintering technique.The phase structure,functional groups,elemental valence states,morphology,optical and photocatalytic activity of the prepared products were characterized by different experimental equipments.The results show that the 10 wt%（Au-C₃N₄）-MgAl₂O₄heterojunction photocatalysts exhibts high optical absorption coefficient,high surface oxygen defects,high carrier transfer and separation efficiency.The 10 wt%（Au-C₃N₄）-MgAl₂O₄heterojunction photocatalysts showed high photocatalytic activity for the degradation of aureomycin hydrochloride under simulated sunlight irradiation.The mechanism analysis showed that the C-O functional group existed in the 10 wt%（Au-C₃N₄）-MgAl₂O₄heterojunction photocatalysts,which cooperated with the SPR effect of Au nanoparticles to accelerate the electron hole separation rate and produce more active species,so that aureorcin hydrochloride could be effectively degraded.