A copper-cobalt oxide catalyst, its preparation method and application

Abstract

This invention discloses a copper-cobalt oxide catalyst, its preparation method, and its application, belonging to the field of wastewater purification technology. The invention uses CuSO4·5H2O, CoSO4·7H2O, and urea as raw materials, volcanic rock fragments as a matrix, and water and triethylene glycol as solvents to prepare a copper-cobalt oxide catalyst. This copper-cobalt bimetallic catalyst can be applied to the catalytic treatment of antibiotic wastewater, exhibiting good activation effects on persulfate. When used to treat antibiotic wastewater containing tetracycline, it can essentially achieve complete removal of tetracycline.

Description

Technical Field

[0001] This invention belongs to the field of wastewater purification technology, and particularly relates to a copper-cobalt oxide catalyst, its preparation method, and its application. Background Technology

[0002] Antibiotics are drugs used to treat bacterial infections, such as cephalosporins, amoxicillin, roxithromycin, and tetracycline hydrochloride. Antiviral drugs are used to treat viral infections; commonly used antiviral drugs include oseltamivir, zanamivir, nevirapine, and efavirenz. Antiviral / antibiotic drugs are widely used due to their effectiveness in treating both viral and bacterial infections. However, improper management of these drugs has led to large quantities entering the ecological environment, causing serious damage and pollution to natural water bodies. Furthermore, antiviral / antibiotic drug wastewater has a complex composition, poor biochemical activity, and is difficult to treat biologically.

[0003] Currently, treatment methods for antibiotic / antiviral drug-contaminated water include adsorption, catalytic degradation, and membrane separation. Among these, catalytic degradation uses chemical methods to break down antibiotics / antiviral drugs into non-toxic substances. This method is relatively thorough and requires no secondary treatment, therefore it is widely used.

[0004] For example, Chinese patent CN107051468A discloses a method for preparing a supported polymetallic oxide ozone catalytic oxidation catalyst. This method uses diatomaceous earth as a support, impregnates the support with a mixed solution of copper nitrate, nickel nitrate, manganese nitrate, cobalt nitrate, and ferric nitrate to obtain a precursor, and then dries and calcines it to obtain the supported polymetallic oxide ozone catalytic oxidation catalyst. This catalyst achieves a COD degradation rate of 50-75% at a dosage of 4 g / L. Chinese patent CN115999547A discloses a method for preparing and applying a supported two-component metal oxide catalytic ozone oxidation catalyst. It uses γ-Al₂O₃ microspheres as a catalyst support, loads copper and cobalt through impregnation, and finally calcines at high temperature to obtain the supported two-component metal oxide catalytic ozone oxidation catalyst. This catalyst achieves a degradation rate of 83-95% for ciprofloxacin, tetracycline, and sulfamethoxazole at a dosage of 80-120 mg / L.

[0005] Neither of these two catalysts achieved complete degradation of antibiotics, and the dosage was relatively high, indicating that the efficiency of the catalysts needs to be improved. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention proposes a copper-cobalt oxide catalyst, its preparation method, and its applications. This catalyst can efficiently activate persulfate (PMS) and effectively degrade antibiotic (tetracycline hydrochloride) wastewater. Compared with traditional catalysts, this catalyst exhibits better catalytic performance, with the generated non-radicals and free radicals serving as the main active species for antibiotic degradation.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] The first aspect of the present invention provides a method for preparing a copper-cobalt oxide catalyst, which uses volcanic rock as a matrix, loads copper salt, cobalt salt and urea by impregnation, prepares a catalyst precursor by hydrothermal reaction, and obtains the copper-cobalt catalyst by drying and calcination.

[0009] In the copper-cobalt catalyst prepared by this invention, CuO can provide oxygen vacancies with electron-rich active centers. Simultaneously, divalent and monovalent copper exhibit interconversion of valence states, generating electrons during this process. These electrons help decompose adsorbed copper oxide on the catalyst surface into various reactive oxygen species. Cobalt oxide can gain stronger free radical adsorption capacity through electron transfer between divalent and trivalent cobalt, thus promoting the catalytic reaction. The participation of urea in the reaction allows for the doping of a certain amount of nitrogen element into the catalyst and promotes the formation of oxygen vacancies. Volcanic rock fragments, as the catalyst support matrix, can effectively support copper oxide and cobalt oxide. Furthermore, volcanic rock itself has a certain adsorption capacity, which helps to synergistically promote the degradation reaction. In addition, the small particle size of single catalyst powder leads to low catalyst recovery rates; adding inexpensive volcanic rock fragments as a support can better achieve catalyst recovery, saving economic costs to a certain extent. The bimetallic copper-cobalt oxide catalyst prepared from the above raw materials can significantly and efficiently activate PMS, thereby generating non-free radicals (…). 1 O2) and free radicals (O2· - SO4 - Active species (such as ·OH) can effectively degrade tetracycline hydrochloride at the active sites provided by the catalyst itself.

[0010] Furthermore, a method for preparing a copper-cobalt oxide catalyst includes the following steps:

[0011] Copper salt, cobalt salt, and urea (CH4N2O) were dispersed in deionized water and triethylene glycol (C6H4N2O). 14 A mixed solution was obtained in a mixed solvent containing O4.

[0012] Volcanic rock fragments were added to the mixed solution and stirred to obtain a supported catalyst.

[0013] The supported catalyst was subjected to a hydrothermal reaction, cooled to room temperature, centrifuged, filtered, dried, and calcined to obtain a copper-cobalt oxide catalyst.

[0014] Copper and cobalt salts are required to have high solubility in water. Optionally, the copper salt includes, but is not limited to, CuSO4, CuCl2, or Cu(NO3)2; the cobalt salt includes, but is not limited to, CoSO4, CoCl2, or Co(NO3)2.

[0015] Furthermore, the mass ratio of the copper salt, cobalt salt, and urea is 1:2:1.

[0016] Furthermore, the volume ratio of the deionized water to triethylene glycol is 1:3.

[0017] Furthermore, the stirring process specifically involves stirring at a speed of 300 rpm for 12 hours.

[0018] Furthermore, the hydrothermal reaction process specifically involves reacting at a temperature of 180°C for 6 hours.

[0019] Furthermore, the drying process specifically involves storing the product in a vacuum drying oven at 90°C for 6 hours.

[0020] Furthermore, the calcination process specifically involves heating the furnace to 500°C at a heating rate of 2°C / min, and then holding the temperature for 2 hours.

[0021] The second aspect of the present invention provides a copper-cobalt oxide catalyst, which is prepared using the above-described preparation method.

[0022] The third aspect of the present invention provides an application of a copper-cobalt oxide catalyst in the treatment of wastewater containing antibiotics.

[0023] Furthermore, the antibiotic is tetracycline hydrochloride.

[0024] The fourth aspect of the present invention provides an advanced oxidation system for degrading tetracycline hydrochloride, using a copper cobalt oxide catalyst as an activator for activating persulfate.

[0025] In this invention, copper and cobalt salts are used as transition metal oxides for synthesizing catalysts, urea is used to dope nitrogen during catalyst synthesis and promote the formation of vacancies in the catalyst, volcanic rock fragments serve as the catalyst support matrix, and water and triethylene glycol are used as solvents to dissolve the aforementioned chemical reagents. The bimetallic copper-cobalt oxide catalyst prepared from the above raw materials can significantly and efficiently activate PMS, thereby generating non-radicals (…). 1 O2) and free radicals (O2· - SO4 -Active species (such as ·OH) can effectively degrade tetracycline hydrochloride at the active sites provided by the catalyst itself.

[0026] Compared with the prior art, the present invention has the following advantages and technical effects:

[0027] This invention utilizes advanced oxidation technology to degrade antibiotic wastewater. A heterogeneous catalyst is used to activate PMS to generate active oxides, effectively degrading organic wastewater. Through catalyst preparation and optimization of a multi-method synergistic catalytic oxidation system, this invention selects catalysts with simple preparation conditions, readily available materials, and good catalytic effects, along with a green, environmentally friendly, simple-to-operate, and highly efficient method for removing antibiotics, resulting in a highly efficient and practical method for treating antiviral / antibiotic wastewater.

[0028] The copper-cobalt oxide catalyst prepared by this invention can effectively activate PMS to generate both free radicals and non-free radicals, thereby efficiently degrading antibiotic wastewater containing tetracycline hydrochloride in a relatively green and economical process. Attached Figure Description

[0029] The accompanying drawings, which constitute part of the present invention, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0030] Figure 1 The catalysts prepared in Example 1 and Comparative Examples 1-4 degrade tetracycline hydrochloride using C t / C0 efficiency curve, where the horizontal axis represents time in minutes and the vertical axis represents C t / C0, unit %, the experiment was conducted at room temperature;

[0031] Figure 2 The curves show the degradation rate constants of tetracycline hydrochloride by the catalysts prepared in Examples 1 and Comparative Examples 1-4. The horizontal axis represents the mass ratio of CuSO4·5H2O to CoSO4·7H2O, and the vertical axis represents k (unit: min). -1 The experiment was conducted at room temperature. Detailed Implementation

[0032] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0033] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0034] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0035] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be illustrative only.

[0036] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0037] This invention provides a method for preparing a copper-cobalt oxide catalyst, comprising the following steps:

[0038] Cobalt salt, copper salt, and urea (CH4N2O) were added to deionized water and triethylene glycol (C6H2O). 14 Stirring the mixture of copper sulfate, cobalt sulfate and urea in a mixed solvent (O4) ensures that copper sulfate, cobalt sulfate and urea are evenly dispersed in the mixed solvent, resulting in a mixed solution.

[0039] Volcanic rock fragments, pulverized to a length, width, and height of approximately 1-3 mm, are added to the mixed solution and stirred together to promote better growth of the mixed solution on the volcanic rock fragments, thus obtaining a supported catalyst.

[0040] The supported catalyst was subjected to a hydrothermal reaction. After the reaction was completed, it was cooled to room temperature. The solution obtained by hydrothermal synthesis was then centrifuged and filtered to obtain the solid catalyst precursor. The catalyst precursor was then dried and calcined to obtain the copper cobalt oxide catalyst.

[0041] In some embodiments, volcanic rocks need to be pre-treated before use. The specific pre-treatment steps are as follows: take volcanic rocks and put them into a sealed bag, wrap the outer layer with foam plastic as a buffer, use a hammer to crush the volcanic rocks into particles of different sizes, sieve and select particles with a length, width and height range of 1-3mm, sonicate in deionized water for 3 hours to remove impurities on the surface of the substrate, then rinse the substrate 3 times with anhydrous ethanol, and put it in an oven to dry.

[0042] The copper and cobalt salts only need to have high solubility in water; that is, the copper and cobalt salts must be soluble. Optionally, the copper salt includes, but is not limited to, CuSO4, CuCl2, or Cu(NO3)2; the cobalt salt includes, but is not limited to, CoSO4, CoCl2, or Co(NO3)2. When used as raw materials, hydrates of copper and cobalt salts are selected. As a typical but non-limiting example, in the embodiments, the copper salt is CuSO4·5H2O, and the cobalt salt is CoSO4·7H2O.

[0043] In one preferred embodiment of the present invention, the mass ratio of CuSO4·5H2O, CoSO4·7H2O and urea is 1:2:1.

[0044] In one preferred embodiment of the present invention, the volume ratio of deionized water to triethylene glycol is 1:3.

[0045] In one preferred embodiment of the present invention, the stirring process specifically involves stirring at a speed of 300 rpm for 12 hours.

[0046] In one preferred embodiment of the present invention, the hydrothermal reaction process specifically involves placing the supported catalyst into a high-pressure reactor and reacting it at 180°C for 6 hours in a vacuum drying oven.

[0047] In one preferred embodiment of the present invention, the drying process specifically involves storing the product in a vacuum drying oven at 90°C for 6 hours.

[0048] In one preferred embodiment of the present invention, the calcination process specifically involves heating the furnace to 500°C at a heating rate of 2°C / min in a tube furnace, and then holding the temperature for 2 hours.

[0049] This invention also provides a method for preparing a copper-cobalt oxide catalyst using the above-described preparation method.

[0050] This invention also provides the application of the copper-cobalt oxide catalyst in the treatment of wastewater containing tetracycline hydrochloride.

[0051] The copper-cobalt oxide catalyst prepared in this invention can significantly and efficiently activate PMS, thereby generating non-radicals (…). 1O2) and free radicals (O2· - SO4 - Active species (such as ·OH) can effectively degrade tetracycline hydrochloride at the active sites provided by the catalyst itself.

[0052] Unless otherwise specified, "room temperature" in this invention refers to 25±2℃.

[0053] All raw materials used in this invention were purchased from the market.

[0054] The technical solution of the present invention is further illustrated by the following examples.

[0055] Example 1

[0056] A method for preparing a copper-cobalt oxide catalyst includes the following steps:

[0057] (1) Pretreatment of the matrix: Take two pieces of volcanic rock and put them into a sealed bag. Wrap the outer layer with foam plastic as a buffer. Use a hammer to crush the volcanic rock into particles of different sizes. After sieving, select particles with a length, width and height in the range of 1-3mm. Sonicate in deionized water for 3 hours to remove impurities on the surface of the matrix. Then rinse the matrix 3 times with anhydrous ethanol and put it in an oven to dry for later use.

[0058] (2) Weigh 0.4g of CuSO4·5H2O, 0.8g of CoSO4·7H2O, and 0.4g of urea, add them to 10mL of deionized water and 30mL of triethylene glycol (C6H4O). 14 In a mixed solvent of CuSO4, the mixture was stirred on a magnetic stirrer until the solution turned grayish-pink, was uniformly mixed, and had no undissolved reagents, thus obtaining a mixed solution (the mass ratio of CuSO4·5H2O and CoSO4·7H2O was 1:2).

[0059] (3) Weigh 2g of the matrix from step (1) and put it into the mixed solution from step (2). Stir together for 12h at a speed of 300rpm to obtain a supported catalyst.

[0060] (4) The supported catalyst was transferred into a 100 mL polytetrafluoroethylene-lined reactor, sealed, and placed in an oven at 180 °C for hydrothermal reaction for 6 hours. After the reaction was completed, the reactor was cooled to room temperature under natural conditions. The product was collected and washed three times by alternating centrifugation with deionized water and anhydrous ethanol (10,000 rpm, 5 min). The washed product was placed in a vacuum drying oven and dried at 90 °C for 6 hours. Finally, the mixed powder was loaded into a quartz boat and placed in the center of a tube furnace. The tube furnace was heated to 500 °C at a heating rate of 2 °C / min in an air atmosphere and calcined at this temperature for 2 hours to obtain a copper cobalt oxide catalyst, named CCO.

[0061] Comparative Example 1

[0062] Same as Example 1, except that in step (2), the mass ratio of CuSO4·5H2O and CoSO4·7H2O is 1:1, that is, 0.4g of CuSO4·5H2O and 0.4g of CoSO4·7H2O.

[0063] Comparative Example 2

[0064] Same as Example 1, except that in step (2), the mass ratio of CuSO4·5H2O and CoSO4·7H2O is 1:3, that is, 0.4g of CuSO4·5H2O and 1.2g of CoSO4·7H2O.

[0065] Comparative Example 3

[0066] Same as Example 1, except that in step (2), the mass ratio of CuSO4·5H2O and CoSO4·7H2O is 2:1, that is, 0.8g of CuSO4·5H2O and 0.4g of CoSO4·7H2O.

[0067] Comparative Example 4

[0068] Same as Example 1, except that in step (2), the mass ratio of CuSO4·5H2O and CoSO4·7H2O is 3:1, that is, 1.2g of CuSO4·5H2O and 0.4g of CoSO4·7H2O.

[0069] Application Example 1

[0070] The performance of the copper-cobalt oxide catalysts prepared in Examples 1 and 1-6 for treating tetracycline hydrochloride wastewater was tested using a direct degradation experiment. The tetracycline hydrochloride degradation reaction was carried out in a 100 mL beaker containing 50 mL of tetracycline hydrochloride (TC) solution. The concentration of tetracycline hydrochloride was 20 mg / L, the PMS concentration was 0.5 mM, and the catalyst dosage was 0.01 g / L. The reaction proceeded for 20 min, with samples taken every 5 min. Immediately after sampling, the water samples were filtered through a 0.22 μm filter membrane and measured using a UV-Vis spectrophotometer at a wavelength of 357 nm. The corresponding absorbance values ​​were obtained and analyzed using the TC solution standard curve (y = 0.0492x - 0.00233 (R0). 2 =0.999)) and the removal rate formula (η=C t The remaining concentration of TC and degradation efficiency were obtained using / C0). The results are as follows: Figure 1 As shown.

[0071] Depend on Figure 1It can be seen that Example 1 exhibits excellent ability to degrade tetracycline hydrochloride even at a dosage of only 10 mg / L. The copper-cobalt oxide catalyst prepared in Example 1 shows the best degradation efficiency for tetracycline hydrochloride, achieving a 100% degradation rate within 20 minutes, thus completely removing tetracycline hydrochloride. Data from Comparative Examples 1 and 2 show that increasing the cobalt doping content improves the overall degradation efficiency, raising the tetracycline hydrochloride degradation rate from 92.4% (Comparative Example 1) to 100%. However, while both Comparative Example 2 and Example 1 achieve complete degradation, the addition of more cobalt increases the risk of cobalt ion leaching. Comparative Examples 3 and 4 show that changing the amount of copper added to the catalyst has almost no effect on the overall degradation efficiency, but... Figure 2 It can be seen that the degradation rate constant of Comparative Example 3 is 0.188, while the degradation rate constant of Example 1 is 0.573, which is about 3 times that of Comparative Example 3. In addition, Comparative Example 4 has a similar overall degradation effect to Example 1, but it has a larger amount of metal salt added, resulting in a waste of resources.

[0072] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. The application of a copper-cobalt oxide catalyst in the treatment of antibiotic-containing wastewater, characterized in that, The antibiotic is tetracycline hydrochloride; The method for preparing the copper-cobalt oxide catalyst involves using volcanic rock as a matrix, loading copper salt, cobalt salt, and urea by impregnation, preparing a catalyst precursor by hydrothermal reaction, and then drying and calcining to obtain the copper-cobalt oxide catalyst; the mass ratio of copper salt, cobalt salt, and urea is 1:2:

1. The particle size of the volcanic rock fragments is 1-3 mm.

2. The application according to claim 1, characterized in that, The preparation method of the copper-cobalt oxide catalyst includes the following steps: A mixed solution was obtained by dispersing copper salt, cobalt salt and urea in a mixed solvent of deionized water and triethylene glycol; Volcanic rock fragment matrix was added to the mixed solution and stirred to obtain a supported catalyst. The supported catalyst was subjected to a hydrothermal reaction, cooled to room temperature, centrifuged, filtered, dried, and calcined to obtain a copper-cobalt oxide catalyst.

3. The application according to claim 1, characterized in that, The copper salt is selected from CuSO4, CuCl2 or Cu(NO3)2; and / or The cobalt salt is CoSO4, CoCl2, or Co(NO3)2.

4. The application according to claim 2, characterized in that, The hydrothermal reaction process specifically involves reacting at 180°C for 6 hours.

5. The application according to claim 2, characterized in that, The drying process is specifically as follows: Store in a vacuum drying oven at 90°C for 6 hours; and / or The calcination process is as follows: in a tube furnace, the temperature is raised to 500°C at a heating rate of 2°C / min, and then held at that temperature for 2 hours.

6. A copper-cobalt oxide catalyst, characterized in that, It was prepared using the method for preparing copper-cobalt oxide catalysts as described in any one of claims 1-5.

7. An advanced oxidation system for degrading tetracycline hydrochloride, characterized in that, The copper-cobalt oxide catalyst of claim 6 is used as the activator for activating persulfate.

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