Study On Catalytic Performance Of Tungsten Keggin Structure Heteropoly Acid Salt For Degradation Of Dye Wastewater

Printing and dyeing wastewater has caused great harm to the environment and human health due to factors such as deep chroma,large emissions,high concentrations of organic pollutants,many types of organic pollutants,and complex components.The traditional treatment method is difficult to achieve the ideal effect of degrading organic pollutants.Ultrasound can use the cavitation effect of ultrasound to finally degrade the pollutants into CO2,H2O or low-molecular-weight small molecules.It has the advantages of high efficiency,energy saving,environmental protection,and avoiding secondary pollution.Therefore,it has received widespread attention from scholars from various countries.As a new type of catalytic material,heteropoly compounds have unique structures,"pseudo-liquid phase"behavior,multifunctionality（strongly acidic,oxidizing,photocatalytic）,low temperature and high activity,and non-toxic,odorless,non-volatile and other advantages.,Has a good application prospect in the field of catalytic research.In this study,four heteropoly acid salt catalysts were prepared by classical acidification.The target dye degradation products were simulated dye wastewater prepared by four typical dyes（methylene blue,crystal violet,alizarin yellow,and rhodamine B）.Catalytic degradation of heteropoly acid salts.In order to solve the problems of heterogeneous compounds having a small specific surface area,being easy to dissolve in solution,and difficult to recover,the grafting method was used to prepare a highly efficient and renewable heterogeneous compound composite catalyst,and its catalytic degradation performance was comprehensively investigated.In this subject,the classic acidification method was used to prepare 1:11 series of Keggin-type Na_5（6）XZr W₁₁O₃₉·n H₂O（X is Mn,Zn,Ti,and Cr）,and infrared spectroscopy（FT-IR）,X-ray diffraction（XRD）,Ultraviolet spectroscopy（UV）detection methods were used to systematically characterize the structure and properties of heteropolyacids.The results show that the synthesized samples have a typical Keggin structure,and have good thermal stability and a regular crystal structure.The experimental results show that Zn Zr W and Ti Zr W have strong catalytic performance,and have strong catalytic degradation effect on methylene blue and crystal violet simulated dye wastewater.The effects of catalysts,initial concentration of dye wastewater,ultrasonic frequency,ultrasonic power,solution temperature,and p H of the solution on the catalytic degradation effect were investigated with the aid of ultrasound.The experimental results show that under the best catalytic conditions,the catalytic degradation rate of heteropolyacid salt Zn Zr W on methylene blue simulated dye wastewater can reach93.5%,and the catalytic degradation rate of crystal violet simulated dye wastewater can reach94.6%.Under the optimal catalytic conditions,the optimal catalytic degradation rate of heteropolyacid salt Ti Zr W for crystal violet quasi dye wastewater can reach 90.6%.The catalytic degradation rate of crystal violet simulated dye wastewater can reach 92.3%.Heteropoly compounds are widely used in the field of catalysis due to their excellent catalytic performance.In this project,the heteropoly compounds are immobilized on Si O₂to make up for the shortcomings of low specific surface area and difficult recovery of the heteropoly compounds.In this study,the grafted method was used to prepare aminated hollow Si O₂particles,and the phosphotungstic acid（HPW）was mounted on NH₂-Si O₂through the coupling agent（APTMS）,and finally the aminated hollow Si O₂phosphotungstic acid composite catalyst NH4PW-Si O₂And the catalyst was analyzed by FT-IR,XRD,SEM,BET and ICP-OES.The catalytic degradation performance of heteropoly compound composite catalyst on simulated dye wastewater was discussed.The effects of catalyst dosage,initial concentration of simulated dye wastewater,solution p H,solution temperature,ultrasonic frequency and ultrasonic power on catalytic degradation were investigated.The experimental results show that under the experimental conditions:catalyst dosage 1.5 g/L,simulated dye wastewater initial concentration 15 mg/L,ultrasonic frequency 60 KHz,ultrasonic power100%,solution p H 7,room temperature,NH₄PW-Si O₂The best catalytic degradation rate of the methylene blue simulated dye wastewater can reach 88.3%.Under experimental conditions:catalyst dosage 1.5 g/L,simulated dye wastewater initial concentration 15 mg/L,ultrasonic frequency 60 KHz,ultrasonic power 100%,solution p H 7,under room temperature conditions,NH₄PW-Si O₂simulates crystal violet The best catalytic degradation rate of dye wastewater can reach 89.6%.Moreover,the regeneration method of NH₄PW-Si O₂is simple.After repeated use for 5 times,the catalytic degradation efficiency has not been significantly reduced.Using the first-order reaction rate equation-d C_t/dt=k C_t,the kinetics of catalytic degradation of typical dye（methylene blue,crystal violet）single-component simulation system was studied,and the apparent reaction order of each typical dye was first order.