Preparation Of Ag₃PO₄/CuWO₄ Complex And Sonocatalytic Degradation Of Dye In Water

With the development of economy and science,the variety and toxicity of organic dyes in industrial wastewater are gradually increasing,so it is urgent to find an effective way to remove industrial wastewater.CuWO₄is an n-type semiconductor.It stands out for its narrow bandgap energy,high chemical stability and high current density.The analysis of the previous experimental results of our group shows that the combination of CuWO₄and ultrasound can enhance the degradation effect of organic pollutants to a certain extent.However,the electron-hole（e^--h⁺）pairs excited by ultrasound quickly recompose.In order to solve this problem,Ag₃PO₄/CuWO₄complexes were constructed.Ag₃PO₄/CuWO₄was used as an acoustic catalyst to remove the simulated dye Congo Red（CR）in combination with ultrasound,the influence of different process parameters on the removal effect of CR was investigated,and the acoustic catalytic method and oxidation method were combined to further enhance the acoustic catalytic activity of Ag₃PO₄/CuWO4 composites,as follows:Firstly,the cubic Ag₃PO₄/CuWO₄complexes were prepared and characterized by two-step method（hydrothermal method and precipitation method）to explore the ultrasonic catalytic removal effect of CR in industrial wastewater.The experimental results show that compared with the pure phase CuWO₄,the prepared Ag₃PO₄/CuWO₄complex has a better removal effect on CR.Moreover,Ag₃PO₄/CuWO₄complex with a composite ratio of 5%had the best effect on CR removal.Under the optimal experimental conditions,that is,the catalyst addition amount was 0.5 g/L,the initial concentration of CR was 50 mg/L,the initial p H of the CR solution was 8,the ultrasonic power was 500 W,and the ultrasonic time was120 min,the maximum removal rate of CR reached 96.82%.Free radical capture experiments showed that the active substances produced by the Ag₃PO₄/CuWO₄acoustically catalyzed reaction were hydroxyl radicals（·OH）,superoxide anion radicals（·O₂^-）and h⁺,and their possible degradation mechanisms were proposed.The results of reuse experiments show that Ag₃PO₄/CuWO₄can maintain high reusability and good stability in acoustic catalytic removal of CR.Secondly,the effects of the addition of H₂O₂and K₂S₂O₈on the acoustic catalytic activity of Ag₃PO₄/CuWO₄were explored.The experimental results show that the H₂O₂addition amount is 20 mmol/L,the recombination ratio of Ag₃PO₄/CuWO₄acoustic catalyst is 5%,the catalyst addition amount is 0.5 g/L,the initial concentration of CR is 50 mg/L,the initial p H solution of CR is 8,the ultrasonic power is 500 W,and the CR removal rate can reach 98.05%within 30 min.The addition amount of K₂S₂O₈is 15 mmol/L,and the CR removal rate can reach99.33%when the ultrasonic time is 5 min under the optimal process conditions,which significantly reduces the cost of acoustic catalytic degradation technology.The results of reuse experiments showed that Ag₃PO₄/CuWO₄added to K₂S₂O₈had good stability and reusability.The effects of different concentrations of anions and cations on the combined ultrasonic removal of CR by K₂S₂O₈/Ag₃PO₄/CuWO₄complexes were also explored,and the results showed that SO₄^2-,CO₃^2-,PO₄^3-,Ag⁺,Cu²⁺,and Fe³⁺had an increasing effect on the acoustic catalytic activity of K₂S₂O₈/Ag₃PO₄/CuWO₄,while Cl^-and NO₃^-had inhibitory effects on the acoustic catalytic activity of K₂S₂O₈/Ag₃PO₄/CuWO₄.Finally,the products after CR degradation were analyzed by total organic carbon（TOC）,ion chromatography（IC）,and liquid chromatography spectrography spectrometry（HPLC-MS）technology,and the possible degradation paths were inferred,so as to better determine whether organic dyes were harmful and polluting to the environment after degradation,which was helpful to verify the feasibility of the method.The above experimental results show that the CR removal rate can be effectively improved by constructing heterojunctions.The combination of acoustic catalysis technology and oxidation can greatly reduce the removal time and then significantly reduce the cost of acoustic catalytic degradation technology.The results of this paper can provide a useful basis for further research and practical chemical production application of Ag₃PO₄/CuWO₄complex in the treatment of organic dye wastewater by acoustic catalysis.