Ag2O / ZnMoO4 composite acoustic catalyst as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of solid ultrasonic catalysis, and particularly relates to an Ag2O / ZnMoO4 composite acoustic catalyst as well as a preparation method and application thereof. According to the Ag2O / ZnMoO4 composite acoustic catalyst, the mass ratios of Ag2O in the Ag2O / ZnMoO4 composite acoustic catalyst are 3%, 5%, 7% and 10% respectively. The Ag2O / ZnMoO4 composite acoustic catalyst provided by the invention has a synergistic effect with potassium persulfate to ultrasonically catalyze and degrade organic dye, the degradation effect is good, equipment is simple, and the method is environment-friendly. By utilizing the method, the degradation rates of methyl orange, Congo red, tetracycline, golden orange II and rose-bengal B in water can reach 89.14%, 88.01%, 76.70%, 54.16% and 94.82% respectively in 5 minutes.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid ultrasonic catalysis, and specifically relates to an Ag2O / ZnMoO4 composite ultrasonic catalyst and a preparation method and application thereof. Background Art

[0002] In recent years, ultrasonic catalytic degradation technology has received widespread attention in the treatment of wastewater containing a large amount of difficult-to-degrade organic pollutants. The core of this technology lies in its high-efficiency degradation ability and the characteristics of no secondary pollution, making it a powerful tool for treating complex sewage problems. The reaction principle of ultrasonic catalytic technology is mainly based on the phenomenon of acoustic cavitation. When ultrasonic waves propagate in water, cavitation bubbles are formed at the bubbles or on the surface of the catalyst. These cavitation bubbles expand rapidly under the action of ultrasonic waves and then burst. This process is accompanied by the generation of local high temperature (up to 5000K) and high pressure (up to 100MPa), and sonoluminescence may also occur. These extreme conditions greatly promote the generation of strong oxidizing monomers such as hydroxyl radicals. These monomers have extremely high reactivity and can effectively react with organic pollutants in sewage. Adding persulfate to the system can introduce new active substances-sulfate radicals (·SO4 - ), which can further improve the wastewater treatment effect. Sulfate radicals have a higher redox potential and a longer half-life than hydroxyl radicals, and are more superior in degrading pollutants under near-neutral to alkaline conditions, so their oxidation effect is better. Summary of the Invention

[0003] One of the purposes of the present invention is to provide an Ag2O / ZnMoO4 composite sonic catalyst which is easy to prepare, has good degradation efficiency, is green and environmentally friendly, and can be reused.

[0004] The second object of the present invention is to provide a method for ultrasonic catalytic degradation of organic dyes by synergistic action of Ag2O / ZnMoO4 composite sonic catalyst and potassium persulfate.

[0005] The technical solution adopted by the present invention is: an Ag2O / ZnMoO4 composite acoustic catalyst, wherein the mass ratio of Ag2O in the Ag2O / ZnMoO4 composite acoustic catalyst is 3%-10%.

[0006] The above-mentioned preparation method of the Ag2O / ZnMoO4 composite acoustic catalyst includes the following steps: preparation of the Ag2O / ZnMoO4 composite acoustic catalyst: weighing ZnMoO4 powder in a conical flask, weighing AgNO3 and dissolving it in 30ml of deionized water, adding the AgNO3 solution to the conical flask, magnetically stirring for 60 minutes, and then ultrasonicating for 30 minutes, then weighing NaOH and dissolving it in 30ml of deionized water, adding the NaOH solution dropwise to the conical flask, stirring thoroughly, centrifuging the mixed solution to collect the precipitate, washing it several times with deionized water and anhydrous ethanol, drying it in a digital display blower drying oven, and cooling and grinding to obtain Ag2O / ZnMoO4.

[0007] The preparation method of the above-mentioned Ag2O / ZnMoO4 composite sound catalyst, the preparation method of ZnMoO4 is as follows: weigh ZnCl2 and Na2MoO4·2H2O and dissolve them in 30ml of deionized water respectively, place the beakers on a magnetic stirrer and stir for 30 minutes, then mix and stir the two for 20 minutes, and then transfer the mixture to a 100ml polytetrafluoroethylene reactor for hydrothermal reaction. After cooling, filter, wash, and dry to obtain ZnMoO4.

[0008] In the above-mentioned method for preparing an Ag2O / ZnMoO4 composite sonic catalyst, the hydrothermal reaction is carried out at a temperature of 453K for 24 hours.

[0009] In the above-mentioned method for preparing the Ag2O / ZnMoO4 composite acoustic catalyst, the drying temperature is 353K.

[0010] The above-mentioned Ag2O / ZnMoO4 composite sonocatalyst is used in the catalytic degradation of organic dyes.

[0011] The above application method is as follows: Ag2O / ZnMoO4 composite sonic catalyst and potassium persulfate are added to a solution containing an organic dye, and the resulting mixed solution is subjected to ultrasonic treatment.

[0012] In the above application, the addition amount of Ag2O / ZnMoO4 composite acoustic catalyst is 1.0 g / L, and the addition amount of potassium persulfate is 30 mmol / L.

[0013] In the above application, the ultrasonic treatment is performed at an ultrasonic frequency of 40 kHz and an ultrasonic power of 500 W for 5 minutes.

[0014] In the above application, the organic dye is one or more of methyl orange, Congo red, tetracycline, golden orange II, and rose bengal B, and the initial concentrations of the organic dye are 10 mg / L, 50 mg / L, 30 mg / L, 5 mg / L, and 2 mg / L, respectively.

[0015] The present invention has the following beneficial effects: the present invention uses a hydrothermal synthesis method to synthesize an Ag2O / ZnMoO4 composite sonocatalyst, and uses the Ag2O / ZnMoO4 composite sonocatalyst and potassium persulfate to synergistically ultrasonically catalyze the degradation of organic dyes such as methyl orange (MO), Congo red (CR), tetracycline (TC), golden orange II (OII), and rose bengal B (RhB). The reaction conditions are mild and the degradation efficiency is high. After a 5-minute ultrasonic reaction, the degradation rate of OII can reach over 50%, the degradation rate of TC can reach over 70%, the degradation rate of MO and CR can reach over 80%, and the degradation rate of RhB can reach over 90%. Moreover, the degradation of organic dyes does not cause secondary environmental pollution, and is an environmentally friendly catalyst. The present invention has the characteristics of high removal efficiency, high safety performance, and low environmental pollution, and shows great application potential in the research of purifying organic dye wastewater. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 1 is the XRD spectrum of the Ag2O / ZnMoO4 composite sonic catalyst with different composite ratios obtained in Example 1.

[0017] Figure 2 These are the scanning electron microscope (SEM) spectra of (A) Ag2O, (B) ZnMoO4 and (C) Ag2O / ZnMoO4 (AZ-5) composite sonocatalysts.

[0018] Figure 3 This is a comparison chart of the effects of stirring adsorption and synergistic sonocatalytic degradation of methyl orange by Ag2O / ZnMoO4 composite sonocatalysts with different composite ratios.

[0019] Figure 4 This is a comparison chart of the effects of synergistic sonocatalytic degradation of methyl orange by Ag2O / ZnMoO4 composite sonocatalyst and different added amounts of potassium persulfate.

[0020] Figure 5 This is the effect diagram of the synergistic sonocatalytic degradation of methyl orange, Congo red, tetracycline, Golden Orange II, and Rose Red B by Ag2O / ZnMoO4 composite sonocatalyst and potassium persulfate.

[0021] Specific example method

[0022] The present invention is described in detail below with reference to the embodiments.

[0023] Example 1 Preparation and Characterization of Ag2O / ZnMoO4 Composite Acoustic Catalyst (I) Preparation of ZnMoO4:

[0024] ZnCl2 and Na2MoO4·2H2O were weighed and dissolved in 30 ml of deionized water respectively. The beakers were placed on a magnetic stirrer and stirred for 30 minutes. The two were then mixed and stirred for 20 minutes. The mixture was transferred to a 100 ml polytetrafluoroethylene reactor and subjected to a hydrothermal reaction at 453 K for 24 hours. After cooling, the mixture was filtered, washed, and dried to obtain ZnMoO4.

[0025] (2) Preparation of Ag2O / ZnMoO4 composite sonic catalysts with different composite ratios:

[0026] Preparation of Ag2O / ZnMoO4 composite sonic catalyst: Take the ZnMoO4 powder obtained in (1) and put it into a conical flask. Weigh AgNO3 and dissolve it in 30 ml of deionized water. Add the AgNO3 solution to the conical flask, stir magnetically for 60 minutes, and then ultrasonicate for 30 minutes. Then add NaOH solution dropwise to the conical flask and stir thoroughly. Collect the precipitate by centrifugation, wash it with deionized water and anhydrous ethanol several times, dry it in a digital display blower drying oven at 353K, and cool and grind it to obtain Ag2O / ZnMoO4.

[0027] According to the different mass ratios of Ag2O in the Ag2O / ZnMoO4 composite sonocatalyst (3%, 5%, 7%, and 10%, respectively, the corresponding mass of ZnCl2 is 0.5452g; the mass of Na2MoO4·2H2O is 0.9678g; the mass of AgNO3 is 0.0204g, 0.0340g, 0.0476g, and 0.0679g), the sonocatalyst can be labeled as "AZ-3", "AZ-5", "AZ-7", and "AZ-10".

[0028] (III) Characterization of Ag2O / ZnMoO4 composite sonocatalyst

[0029] Figure 1 The XRD spectra of Ag2O / ZnMoO4 composite sonic catalysts with different composite ratios are shown in Figure 2. Figure 1 It can be seen that when the composite ratio of Ag2O is 3%-10%, the XRD spectrum of the synthesized Ag2O / ZnMoO4 composite sonic catalyst is consistent with the standard card JCPDS No.16-0310 of ZnMoO4. Compared with the XRD spectrum of Ag2O, the diffraction peak of Ag2O is slightly presented in the XRD spectrum of the Ag2O / ZnMoO4 composite sonic catalyst. This may be because the main body is ZnMoO4, the Ag2O content is very small, and no other impurities are produced. This shows that a high-purity Ag2O / ZnMoO4 composite material has been successfully prepared.

[0030] Figure 2The following are the scanning electron microscope (SEM) spectra of (A) Ag2O (B) ZnMoO4 (C) Ag2O / ZnMoO4 (AZ-5) composite sonic catalysts. Figure 2 As can be seen, Ag2O exhibits a relatively uniform nanosphere shape, with a fluffy sphere and a relatively smooth surface. ZnMoO4 exhibits a stacked layered morphology, composed of numerous thin flakes. The main morphology of AZ-5 is a stack of flakes supported by nanospheres. As can be seen in the figure, after the Ag2O composite, some nanospheres are evenly attached to the ZnMoO4 surface, indicating the successful preparation of the AZ-5 composite catalyst.

[0031] Example 2 Application of Ag2O / ZnMoO4 composite sonic catalyst, potassium persulfate and ultrasound composite system in degrading organic dye wastewater

[0032] (1) Ag2O / ZnMoO4 composite sonic catalyst synergistic ultrasonic catalytic degradation method:

[0033] Weigh 0.04 g of Ag2O / ZnMoO4 composite sonocatalysts with different composite ratios into a 150 mL Erlenmeyer flask. Add 40 mL of a 10.0 mg / L MO solution. Stir for 30 minutes in the dark to allow adsorption-desorption equilibrium between the sonocatalyst particles and the MO solution to be reached. After adsorption is complete, remove the supernatant liquid using a disposable dropper into a test tube and centrifuge. After centrifugation, pipette the supernatant into a quartz cuvette and measure its absorbance at 465 nm using a UV-visible spectrophotometer. Record the data. The absorbance values are used to calculate the dye adsorption rate. The remaining liquid in the Erlenmeyer flask is transferred to a digitally controlled ultrasonic cleaner and sonicated at 313 K for 120 minutes. The sonication process must also be performed in the dark. After the ultrasound, samples were taken and centrifuged. After the same centrifugation, the supernatant was pipetted into a quartz cuvette and its absorbance was detected at 465 nm using a UV-visible spectrophotometer. The adsorption and degradation efficiency of the Ag2O / ZnMoO4 composite sonocatalyst were calculated, and the reactions of the Ag2O / ZnMoO4 composite sonocatalysts with different composite ratios added to the methyl orange solution were compared.

[0034] (2) Method for synergistic sonocatalytic degradation of methyl orange using Ag2O / ZnMoO4 composite sonocatalyst and different amounts of potassium persulfate:

[0035] In this experiment, AZ-5 was selected as the sonocatalyst at a dosage of 1.0 g / L, the initial MO dye concentration was 10 mg / L, the sonication time was 60 minutes, the ultrasonic power was 500 W, and the initial pH of the MO dye was 6.0. After the sonication reaction, the mixture was sampled and centrifuged, and the supernatant was measured for UV absorbance. The sonocatalytic degradation efficiency of methyl orange using the Ag2O / ZnMoO4 composite sonocatalyst AZ-5 in combination with different dosages of potassium persulfate was calculated. The K2S2O8 concentrations used were 0 mmol / L, 20 mmol / L, 30 mmol / L, 40 mmol / L, and 50 mmol / L, respectively.

[0036] (III) Method for the synergistic sonocatalytic degradation of organic dyes using Ag2O / ZnMoO4 composite sonocatalyst and potassium persulfate:

[0037] The AZ-5 catalyst was added at a dosage of 1.0 g / L, the K₂S₂O₄ concentration was 30 mmol / L, the ultrasonication time was 5 minutes, and the ultrasonic power was 500 W. After the ultrasonic reaction, the mixture was sampled and centrifuged, and the supernatant was collected for UV absorbance measurement. The sonocatalytic degradation efficiency of various organic dyes using the Ag₂O / ZnMoO₄ composite sonocatalyst AZ-5 in synergy with potassium persulfate was calculated. The organic pollutants and their initial concentrations were: MO (10 mg / L), CR (50 mg / L), TC (30 mg / L), OⅡ (5 mg / L), and RhB (2 mg / L).

[0038] (IV) Testing:

[0039] Figure 3 The figure compares the effects of Ag2O / ZnMoO4 composite sonocatalysts with different composite ratios on stirring adsorption and synergistic sonocatalytic degradation of methyl orange. As shown in the figure, the adsorption rates of MO (adsorption removal efficiency of Rhodamine B) of ZnMoO4, AZ-3, AZ-5, AZ-7, and AZ-10 are 1.32 (±0.1)%, 1.01 (±0.28)%, 0.13 (±0.2)%, 2.08 (±0.54)%, and 1.66 (±0.2)%, respectively. The removal rates of MO (synergistic sonocatalytic degradation efficiency of Rhodamine B) are 12.59 (±2.7)%, 33.67 (±6.81)%, 84.71 (±1.52)%, 46.45 (±3.98)%, and 27.26 (±8.71)%, respectively. It can be seen that the sonocatalytic performance of the prepared composite catalysts is higher than that of pure ZnMoO4, indicating that the doping of Ag2O is beneficial to improving the sonocatalytic activity of ZnMoO4, and when the molar ratio of Ag2O / ZnMoO4 is 5%, that is, AZ-5, the removal rate of methyl orange is the highest.

[0040] Figure 4The synergistic sonocatalytic degradation of methyl orange using the Ag2O / ZnMoO4 composite sonocatalyst and varying amounts of potassium persulfate is shown in the figure. As can be seen, when the sonication time is 30 minutes and the initial potassium persulfate concentration increases from 0 mmol / L to 50 mmol / L, the MO removal rate gradually increases, reaching 58.47 (±7.16)%, 89.27 (±0.30)%, 92.29 (±0.14)%, 92.45 (±0.41)%, and 94.24 (±0.50), respectively.

[0041] Figure 5 This is the effect diagram of the synergistic ultrasonic catalytic degradation of different organic dyes by Ag2O / ZnMoO4 composite sonocatalyst AZ-5 and potassium persulfate. Figure 5 The K2S2O8 / AZ-5 / US system achieved removal efficiencies of 89.14%, 88.01%, 76.70%, 54.16%, and 94.82% for MO, CR, TC, OⅡ, and RhB, respectively. These results demonstrate that the addition of K2S2O8 enhances the sonocatalytic activity of the AZ-5 catalyst for various organic pollutants, demonstrating its potential application and providing a foundation for practical applications in organic wastewater treatment.

Claims

1. An Ag2O / ZnMoO4 composite acoustic catalyst, characterized in that: In the Ag2O / ZnMoO4 composite sonic catalyst, the mass ratio of Ag2O in the Ag2O / ZnMoO4 composite sonic catalyst is 3%-10%.

2. The method for preparing the Ag2O / ZnMoO4 composite acoustic catalyst according to claim 1, characterized in that: The method comprises the following steps: weighing ZnMoO4 powder into a conical flask, dissolving AgNO3 in deionized water, adding the AgNO3 solution into the conical flask, magnetically stirring, ultrasonicating, adding NaOH solution dropwise into the conical flask, stirring thoroughly, centrifuging the mixed solution to collect precipitates, washing several times, drying, cooling and grinding to obtain Ag2O / ZnMoO4.

3. The method for preparing a Ag2O / ZnMoO4 composite acoustic catalyst according to claim 2, characterized in that: The preparation method of ZnMoO4 is as follows: ZnCl2 and Na2MoO4·2H2O are weighed and dissolved in deionized water respectively, and stirred separately, and then the two are mixed and stirred, and the mixed solution is transferred to a polytetrafluoroethylene reactor for hydrothermal reaction. After cooling, the mixture is filtered, washed, and dried to obtain ZnMoO4.

4. The method for preparing the Ag2O / ZnMoO4 composite acoustic catalyst according to claim 3, characterized in that: The hydrothermal reaction is carried out at a temperature of 453K for 24 hours.

5. The method for preparing a Ag2O / ZnMoO4 composite acoustic catalyst according to claim 2, characterized in that: The drying temperature is 353K.

6. Use of the Ag2O / ZnMoO4 composite sonocatalyst according to claim 1 in catalytic degradation of organic dyes.

7. The use according to claim 6, characterized in that The method is as follows: Ag2O / ZnMoO4 composite acoustic catalyst and potassium persulfate are added to a solution containing an organic dye, and the obtained mixed solution is subjected to ultrasonic treatment.

8. The use according to claim 7, characterized in that The addition amount of Ag2O / ZnMoO4 composite sonic catalyst was 1.0 g / L, and the addition amount of potassium persulfate was 30 mmol / L.

9. The use according to claim 7, characterized in that The ultrasonic treatment is carried out at an ultrasonic frequency of 40 kHz and an ultrasonic power of 500 W for 5 minutes.

10. The use according to any one of claims 6 to 9, characterized in that: The organic dye is one or more of methyl orange, Congo red, tetracycline, golden orange II, and rose bengal, and the initial concentrations of the organic dye are 10 mg / L, 50 mg / L, 30 mg / L, 5 mg / L, and 2 mg / L, respectively.

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