An Ag 2 WO 4 / CuBi 2 O 4 Composite material for use in ultrasonic catalytic degradation of organic pollutants in wastewater

Abstract

The present invention belongs to the technical field of solid ultrasonic catalysis, and specifically relates to the application of an Ag2WO4 / CuBi2O4 composite material in the ultrasonic catalytic degradation of organic pollutants in wastewater. The method is as follows: Add the Ag2WO4 / CuBi2O4 composite material to the wastewater containing organic pollutants, and under an ultrasonic power of 500 W, ultrasonicate for 2 h. The degradation rate of tetracycline in water can reach 85.05 ± 4.84%.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid ultrasonic catalysis, and particularly relates to an application of an Ag 2 WO 4 / CuBi 2 O 4 composite material in ultrasonic catalytic degradation of organic pollutants in wastewater. Background Art

[0002] At present, environmental pollution and health risks caused by the abuse of antibiotics have become a research hotspot in recent years. Tetracycline is a broad-spectrum antibiotic and is widely used in the treatment of diseases in animal husbandry and aquaculture due to its low price. In addition, tetracycline has high water solubility and a long half-life, and its stable parent nucleus structure makes it impossible to be removed by traditional treatment technologies. There are often reports showing the presence of tetracycline detected in surface water, groundwater and sediments. To sum up, finding a wastewater treatment technology with good removal effect on tetracycline and antibiotics is a crucial link. Summary of the Invention

[0003] The purpose of the present invention is to provide an Ag 2 WO 4 / CuBi 2 O 4 composite material, as an efficient and environmentally friendly acoustic catalyst for effectively solving water pollution, has broad application potential.

[0004] The technical solution adopted by the present invention is: an application of an Ag 2 WO 4 / CuBi 2 O 4 composite material in ultrasonic catalytic degradation of organic pollutants in wastewater, and the method is as follows: adding Ag 2 WO 4 / CuBi 2 O 4 composite material into the wastewater containing organic pollutants, and ultrasonicating for 2 h at an ultrasonic power of 500 W.

[0005] In the above application, the organic pollutant is tetracycline.

[0006] In the above application, the initial concentration of the organic pollutant is 40 mg / L.

[0007] In the above application, in the organic pollutant, Ag 2 WO 4 / CuBi 2 O 4The addition amounts of the composite material are 0, 0.5 g / L, 1 g / L, 1.5 g / L, and 2 g / L respectively.

[0008] In the above application, Ag 2 WO 4 / CuBi 2 O 4 The preparation method of the composite material includes the following steps: While stirring, slowly drip the AgNO 2 O 4 aqueous solution into the CuBi 3 suspension, stir under dark conditions, slowly add the Na 2 WO 4 ·2H 2 O aqueous solution into the above mixed solution, and continue to stir, filter, wash and dry in a dark environment to obtain Ag 2 WO 4 / CuBi 2 O 4 composite material.

[0009] In the above application, the preparation method of CuBi 2 O 4 includes the following steps: Stir the dilute nitric acid solution of Bi(NO 3 ) 3 ·5H 2 O, while stirring, pour the Cu(NO 3 ) 2 ·5H 2 O aqueous solution into it, then slowly add the NaOH solution to obtain a white-green suspension and continue to stir. After stirring, carry out a hydrothermal reaction. After the reaction is completed, filter, wash, dry and grind to obtain CuBi 2 O 4 powder.

[0010] In the above application, the condition of the hydrothermal reaction is to react at 180 °C for 12 h.

[0011] In the above application, drying is carried out at 60 °C for 12 h.

[0012] In the above application, Ag 2 WO 4 accounts for 10%-40% of the mass of the added CuBi 2 O 4 by mass.

[0013] In the above application, Ag 2 WO 4 accounts for 30% of the mass of the added CuBi 2 O 4 by mass.

[0014] The beneficial effects of the present invention are as follows: CuBi 2 O 4 is a novel bismuth-based catalyst with characteristics such as a wide range of light energy utilization and strong photoreaction activity. Constructing a heterojunction is an effective means to improve the catalytic activity of CuBi 2 O 4 . And Ag 2 WO 4 has good photocatalytic performance and excellent electrical conductivity. In addition to possessing the excellent properties of silver-based catalysts, the preparation process of Ag 2 WO 4 is simple, and it is considered to be one of the most effective semiconductors at present. After the present invention combines the two, by adding different masses of Ag 2 WO 4 / CuBi 2 O 4 composite materials and combining ultrasonic degradation of tetracycline, the results show that the prepared Ag 2 WO 4 / CuBi 2 O 4 composite materials have the advantages of good degradation effect, simple preparation method, non-toxicity, etc., providing a new solution for the ultrasonic catalytic treatment of organic pollutants in wastewater. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Figure 39 shows the XRD spectra of Ag 2 WO 4 / CuBi 2 O 4 composite materials with different composite ratios obtained in Example 1.

[0016] Figure 2 Figure 51 shows the SEM images of CuBi 2 O 4 (A), Ag 2 WO 4 (B) and the composite ACBO (C).

[0017] Figure 3 Figure 63 shows the change image of the removal rate of tetracycline in the ACBO sono-catalytic system under different Ag 2 WO 4 composite percentages.

[0018] Figure 4 Figure 71 shows the effect of the dosage of ACBO-30 on the removal rate of tetracycline.

[0019] DETAILED DESCRIPTION OF THE SPECIFIC EMBODIMENTS

[0020] The present invention will be described in detail below with reference to the embodiments.

[0021] Example 1

[0022] (1) Ag with different compounding ratios 2 WO 4 / CuBi 2 O 4 Preparation of composite material

[0023] (1) Preparation of CuBi 2 O 4 : Precisely weigh 784.0 mg of Bi(NO 3 ) 3 5H 2 O with an analytical balance, dissolve it in 20 mL of dilute nitric acid (1 mol / L) to inhibit its hydrolysis, and prepare a solution for later use. Then weigh 241.6 mg of Cu(NO 3 ) 2 ·3H 2 O with an analytical balance, dissolve it in 20 mL of deionized water to obtain a Cu(NO 3 ) 2 ·3H 2 O solution. Place the above Bi(NO 3 ) 3 ·5H 2 O solution on a magnetic stirrer, and pour the Cu(NO 3 ) 2 ·5H 2 O solution into it while stirring, and maintain for 30 min. While maintaining the stirring state, slowly add 20 mL of 2 mol / L NaOH solution to the mixed solution of Cu(NO 3 ) 2 ·5H 2 O and Bi(NO 3 ) 3 5H 2 O to obtain a white-green suspension, and continue stirring for 360 min. After the stirring is completed, transfer the suspension to a 100 mL reaction kettle, wait for the oven to preheat to 180 °C and then put the reaction kettle in, and react at 180 °C for 12 h. After the reaction is completed, wait for the reaction kettle to cool to room temperature, filter by suction to obtain a brown solid, wash it repeatedly 3 times each with alcohol and water, and then place it in a vacuum drying oven at 60 °C for drying for 12 h. Take out the dried product, grind it to obtain CuBi 2 O 4 powder.

[0024] (2) Preparation of Ag 2 WO 4 composite material: Weigh 0.02 mol of AgNO 3 and 0.01 mol of Na 2 WO 4 ·2H 2O and dissolve them separately in 35 mL of deionized water. After fully stirring and dissolving, obtain AgNO 3 and Na 2 WO 4 ·2H 2 O solution. On a magnetic stirrer device, add the AgNO 3 solution to the Na 2 WO 4 ·2H 2 O solution. After stirring the two for 60 min, perform suction filtration and washing, and dry at 60 °C for 6 h. Take out and grind for later use.

[0025] 3) Preparation of Ag 2 WO 4 / CuBi 2 O 4 Composite material: Accurately weigh 500 mg of CuBi 2 O 4 powder and place it in 20 mL of deionized water, and ultrasonically disperse it on an ultrasonic cleaner for 30 min. Weigh a certain amount of AgNO 3 and dissolve it in 20 mL of deionized water. After fully stirring and dissolving, prepare an AgNO 3 solution. Place the CuBi 2 O 4 suspension on a magnetic stirrer, and slowly drip the AgNO 3 solution while stirring, and continue to stir in a dark environment for 60 min. Weigh a certain amount of Na 2 WO 4 ·2H 2 O and dissolve it in deionized water to prepare 20 mL of Na 2 WO 4 ·2H 2 O solution. Slowly add the Na 2 WO 4 ·2H 2 O solution to the above mixed solution, and continue to stir in a dark environment for 60 min. After the stirring is completed, perform suction filtration on the mixed solution of the above three, wash it repeatedly with anhydrous ethanol and deionized water alternately, and then place it in a vacuum drying oven at 60 °C for 12 h. Grind the obtained dried product Ag 2 WO 4 / CuBi 2 O 4 and mark for later use.

[0026] Name the composite according to the theoretical yield of Ag 2 WO 4 and the proportion of 500 mg of CuBi 2 O 4 , such as Ag 2WO 4 The theoretical yield is 50 mg, then Ag 2 WO 4 / CuBi 2 O 4 The composite is named ACBO-10. ACBO-10, ACBO-20, ACBO-30, and ACBO-40 were synthesized respectively according to this method.

[0027] (2) Ag 2 WO 4 / CuBi 2 O 4 Characterization of the composite material

[0028] Figure 1 are the Ag with different composite ratios obtained 2 WO 4 / CuBi 2 O 4 XRD patterns of the composite materials. From Figure 1 it can be seen that from the results presented by the prepared pure CuBi 2 O 4 by comparing with the standard card (NO. 71-1774) of CuBi 2 O 4 it can be known that the diffraction peaks observed in the figure can be well attributed to the (200), (211), (002), (130), (202), (141), (123), (521) crystal planes of CuBi 2 O 4 and it has good crystallinity. Secondly, significant diffraction peaks can be observed at 2θ = 18.4°, 30.1°, 32.2°, 44.6°, 56.1°, 57.5°, 59.2° in the diffraction pattern of Ag 2 WO 4 prepared in this article. The above diffraction peaks correspond to the (020), (022), (220), (042), (242), (060), (224) in Ag 2 WO 4 respectively. The above results indicate that pure CuBi 2 O 4 without impurities and pure Ag 2 WO 4 sample materials were synthesized in this experiment. Then, it can be seen from the XRD pattern results of different composites in the figure that when the composite percentage of Ag 2 WO 4 rises in the range of 10% to 40%, in addition to observing CuBi 2 O 4In addition to the diffraction peaks corresponding to the substrate, the diffraction peaks corresponding to Ag can also be clearly observed from the XRD images. 2 WO 4 The intensity of the diffraction peaks increases with the increase of the composite ratio. This result indicates that in this experiment, Ag 2 O 4 has been successfully composited on the surface of CuBi 2 WO 4 .

[0029] Figure 2 are the SEM images of CuBi 2 O 4 (A), Ag 2 WO 4 (B), and the composite ACBO (C). As can be seen from Figure 2 , CuBi 2 O 4 synthesized by the hydrothermal method has a spherical morphology with a smooth surface, and its diameter is about 5 μm. Ag 2 WO 4 synthesized by the precipitation method presents a cubic shape and there is a slight agglomeration phenomenon. At the same time, the composite ACBO synthesized by the two-step method shows a morphology of spherical CuBi 2 O 4 with several cubic particles wrapped on its surface, and the surface is rougher than that of CuBi 2 O 4 . This result shows that Ag 2 WO 4 has been successfully attached to the surface of CuBi 2 O 4 .

[0030] Example 2 Degradation of tetracycline by the synergistic ultrasonic catalysis of Ag 2 WO 4 / CuBi 2 O 4 composite materials

[0031] (I) Method for removing tetracycline by stirring and adsorption of Ag 2 WO 4 / CuBi 2 O 4 composite materials:

[0032] Use an analytical balance to weigh 20 mg of CuBi 2 O 4 , and at this time Ag 2 WO 4The composite ratio was regarded as 0%, and it was added to a 250 mL conical flask. 20 mL of a tetracycline solution with a concentration of 40 mg / L was added to the flask. The conical flask was placed on a magnetic stirrer and stirred for 30 min under dark conditions. After stirring, the sample was taken for centrifugation, and the supernatant was taken. The absorbance was measured with a UV-visible spectrophotometer, and the adsorption and removal efficiency of CuBi 2 O 4 composite material for tetracycline adsorption and removal was determined. The adsorption and removal rates of ACBO-10, ACBO-20, ACBO-30, and ACBO-40 for tetracycline were measured according to the same method, and the reactions of Ag 2 WO 4 / CuBi 2 O 4 composite materials with different composite ratios in the tetracycline solution were compared.

[0033] (2) Method for the synergistic ultrasonic catalytic degradation of tetracycline by Ag 2 WO 4 / CuBi 2 O 4 composite materials:

[0034] Weigh 20 mg of CuBi 2 O 4 using an analytical balance. At this time, the Ag 2 WO 4 composite ratio was regarded as 0%, and it was added to a 250 mL conical flask. 20 mL of a tetracycline solution with a concentration of 40 mg / L was added to the flask. The above conical flask was placed above an ultrasonic cleaner using an iron stand, such that the water surface in the instrument just contacted the bottom of the conical flask. Then, a black plastic bag was used to provide a dark environment for the reaction to remove the interference of the light source. Ultrasonic treatment was carried out at an ultrasonic power of 500 W for 120 min. The reaction solution was drawn out using a syringe and filtered through a membrane to obtain the supernatant. The absorbance was measured by a UV spectrophotometer, and the ultrasonic degradation efficiency of CuBi 2 O 4 composite material for tetracycline was determined. The synergistic ultrasonic catalytic degradation efficiencies of ACBO-10, ACBO-20, ACBO-30, and ACBO-40 for tetracycline were measured according to the same method, and the reactions of Ag 2 WO 4 / CuBi 2 O 4 composite materials with different composite ratios in the tetracycline solution were compared.

[0035] (3) Method for the stirred adsorption and removal of tetracycline by Ag 2 WO 4 / CuBi 2 O 4 composite materials:

[0036] Accurately weigh 10 mg of ACBO-30 using a balance and add it to a 250 mL conical flask. Add a 40 mg / L tetracycline solution to the conical flask, place the conical flask on a magnetic stirrer and stir for 30 min, and carry out the operation under dark conditions. After stirring is completed, take a sample and centrifuge it to collect the supernatant sample, and calculate the adsorption and removal rate of ACBO-30 for tetracycline by measuring the absorbance. Similarly, change the dosage of ACBO-30 to 0 mg, 20 mg, 30 mg, and 40 mg and measure the adsorption and removal rates under different dosages respectively.

[0037] (4) Ag with different addition amounts 2 WO 4 / CuBi 2 O 4 Method for synergistic ultrasonic catalytic degradation of tetracycline by composite materials:

[0038] Accurately weigh 10 mg of ACBO-30 using a balance and add it to a 250 mL conical flask. Add a 40 mg / L tetracycline solution to the conical flask, and accurately place the conical flask above the ultrasonic site. Cover it with a black plastic bag to create a dark environment, and ultrasonicate for 120 min at a power of 500 W. Collect the supernatant sample, and calculate the ultrasonic degradation rate of ACBO-30 synergistic ultrasonic for tetracycline by measuring the absorbance. Similarly, change the dosage of ACBO-30 to 0 mg, 20 mg, 30 mg, and 40 mg and measure the ultrasonic degradation rates under different dosages respectively.

[0039] (5) Testing

[0040] Figure 3 is Ag with different composite ratios 2 WO 4 / CuBi 2 O 4 Comparison chart of the efficiency of composite materials for adsorbing and removing tetracycline and synergistic ultrasonic catalytic degradation of tetracycline. As Figure 3 shown, the adsorption and removal rates of CuBi 2 O 4 、ACBO-10、ACBO-20、ACBO-30、ACBO-40 for tetracycline hydrochloride are 15.97 (±2.46)%, 34.80 (±1.64)%, 31.62 (±0.21)%, 27.28 (±4.16)%, 27.44 (±5.26)% respectively, and the ultrasonic degradation rates for tetracycline hydrochloride are 60.69 (±6.90)%, 70.18 (±10.59)%, 80.83 (±4.74)%, 87.14 (±3.88)%, 57.67 (±9.23)% respectively. When Ag 2 WO 4 is compounded with CuBi2 O 4 After that, the removal rate of tetracycline by the ACBO sono-catalytic system showed a trend of first increasing and then decreasing, and reached the maximum removal rate when the composite ratio was 30%. When the 2 WO 4 composite ratio of increased from 10% to 30%, the phenomenon of increased removal rate can be considered that the addition of 2 WO 4 adhered to the surface of CuBi 2 O 4 increased the specific surface area and active sites of the catalyst material. However, excessive 2 WO 4 covered the original reactive sites of CuBi 2 O 4 resulting in a decrease in the ultrasonic degradation rate of tetracycline.

[0041] Figure 4 shows the comparison chart of the efficiency of tetracycline adsorption and removal and the synergistic ultrasonic catalytic degradation of tetracycline by different dosages of 2 WO 4 / CuBi 2 O 4 composite materials. As Figure 4 shown, the adsorption and removal rates of tetracycline by ACBO-30 with dosages of 0.5 g / L, 1 g / L, 1.5 g / L, and 2 g / L were 15.28 (±1.89)%, 15.96 (±4.97)%, 21.28 (±2.07)%, and 24.62 (±1.99)%, respectively. The ultrasonic degradation rates of tetracycline by ACBO-30 with dosages of 0, 0.5 g / L, 1 g / L, 1.5 g / L, and 2 g / L were 12.16 (±3.72)%, 79.36 (±3.89)%, 85.05 (±4.84)%, 77.79 (±10.04)%, and 74.86 (±10.68)%, respectively. It can be seen that when the dosage of the catalyst ACBO-30 increased from 0.5 g / L to 2.0 g / L, the ultrasonic degradation rate of tetracycline first increased and then decreased. This is because the dosage of the catalyst provided more active sites for adsorption and oxidation, which affected the number of "cavitation bubbles" formed due to heterogeneous nucleation in the solution to a certain extent, thus improving the ultrasonic degradation rate of tetracycline. However, once the ideal dosage of the catalyst was exceeded, the excessive catalyst would hinder the penetration ability of ultrasonic waves and "sonoluminescence".

Claims

1. Application of Ag2WO4 / CuBi2O4 composite material in ultrasonic catalytic degradation of organic pollutants in wastewater, characterized in that: The method is as follows: add Ag2WO4 / CuBi2O4 composite material to wastewater containing organic pollutants, and ultrasonicate for 2 hours at an ultrasonic power of 500W; The preparation method of the Ag2WO4 / CuBi2O4 composite material comprises the following steps: slowly dripping an AgNO3 aqueous solution into a CuBi2O4 suspension while stirring, stirring under dark conditions, slowly adding an Na2WO4·2H2O aqueous solution into the mixed solution, and continuing to stir, filtering, washing and drying under dark conditions to obtain an Ag2WO4 / CuBi2O4 composite material, wherein the mass of the Ag2WO4 accounts for 10%-30% of the mass of the added CuBi2O4.

2. The use according to claim 1, characterized in that: The organic pollutant is tetracycline.

3. The use according to claim 1, characterized in that: The initial concentration of organic pollutants was 40 mg / L.

4. The use according to claim 1, characterized in that: Among the organic pollutants, the addition amounts of Ag2WO4 / CuBi2O4 composite materials were 0.5g / L, 1g / L, 1.5g / L, and 2g / L, respectively.

5. The use according to claim 1, characterized in that: The preparation method of CuBi2O4 includes the following steps: stirring a dilute nitric acid solution of Bi(NO3)3·5H2O, pouring a Cu(NO3)2·5H2O aqueous solution therein while stirring, and then slowly adding a NaOH solution to obtain a white-green suspension and continuing to stir, and after the stirring is completed, performing a hydrothermal reaction, and after the reaction is completed, filtering, washing, drying, and grinding to obtain CuBi2O4 powder.

6. The use according to claim 5, characterized in that: The hydrothermal reaction was carried out at 180°C for 12 h.

7. The use according to claim 1 or 5, characterized in that: Drying was carried out at 60°C for 12 h.

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