A modified vermiculite-loaded cubic cobalt-manganese spinel material and its preparation method

Abstract

The present invention discloses a modified vermiculite-loaded cubic cobalt-manganese spinel material and a preparation method thereof, belonging to the technical field of environmental remediation functional materials. The present invention first synthesizes cubic cobalt-manganese spinel by in-situ coprecipitation on the surface and interlayers of vermiculite. The vermiculite-loaded cubic cobalt-manganese spinel material is then modified using hexadecyltrimethylammonium bromide to prepare the modified vermiculite-loaded cubic cobalt-manganese spinel material. The reaction conditions are mild, and no toxic or hazardous raw materials are involved. The prepared catalyst is stable, efficient, and environmentally friendly, effectively reducing the activation energy of oxidants such as peroxymonosulfate, thereby achieving efficient removal of perfluorooctanoic acid.

Description

Technical Field

[0001] The invention belongs to the technical field of environmental restoration functional materials, and in particular relates to a modified vermiculite-loaded cubic cobalt-manganese spinel material and a preparation method thereof. Background Art

[0002] Perfluorooctanoic acid (PFOA), a perfluorinated compound widely used in industry, is highly environmentally persistent and bioaccumulative due to the large number of stable carbon-fluorine (CF) bonds in its molecules. PFOA is difficult to degrade through natural processes and persists in the environment for a long time, posing a serious threat to ecosystems and negatively impacting human health. Summary of the Invention

[0003] To this end, the present invention proposes a modified vermiculite-loaded cubic cobalt-manganese spinel material and a preparation method thereof.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] One of the objectives of the present invention is to provide a method for preparing a modified vermiculite-loaded cubic cobalt manganese spinel material. First, cubic cobalt manganese spinel (Co2MnO4, CM) is synthesized by in situ co-precipitation on the surface and interlayer of vermiculite (VT). Then, the vermiculite-loaded cubic cobalt manganese spinel material is modified by using hexadecyltrimethylammonium bromide to prepare a modified vermiculite-loaded cubic cobalt manganese spinel material.

[0006] Vermiculite is a layered silicate material with a large specific surface area and abundant adsorption sites. Therefore, it has good adsorption properties for organic pollutants, enriching them on the catalyst surface, thereby increasing the local concentration of reactants and accelerating the degradation reaction. Cubic cobalt manganese spinel (CM) has a stable electronic structure and can effectively activate peroxymonosulfate (PMS) to generate sulfate radicals (SO4 •−) and hydroxyl radicals (•OH), which attack perfluorooctanoic acid molecules, thereby degrading PFOA. The synergistic effect of cobalt and manganese optimizes the material's electronic structure and enhances its catalytic performance. Cobalt ions have excellent redox properties, while manganese ions modulate the material's electronic structure, enhancing its activation of PMS. When vermiculite is composited with cubic cobalt manganese spinel, the vermiculite's ion exchangeability enables interaction with the metal ions in the spinel, enhancing the material's stability and catalytic activity. Hexadecyltrimethylammonium bromide, a cationic surfactant, is introduced into the vermiculite-loaded cubic cobalt manganese spinel material to introduce positive charges on the surface. Since perfluorooctanoic acid molecules are negatively charged, this positive charge enhances the material's adsorption capacity for PFOA, further improving degradation efficiency. Modification with hexadecyltrimethylammonium bromide also increases active sites on the material's surface, which are better able to adsorb and activate PMS, thereby increasing the reaction rate. The present invention synthesizes cubic cobalt-manganese spinel in situ on the surface and interlayers of vermiculite by a co-precipitation method, ensuring that CM is uniformly loaded on the vermiculite and avoiding particle agglomeration, thereby increasing the specific surface area and the number of active sites of the material. The material is then modified at a certain temperature. The method adopts mild reaction conditions, does not involve toxic or hazardous raw materials, and is conducive to maintaining the structural integrity and catalytic activity of the material.

[0007] The specific steps include:

[0008] (1) dissolving sodium hydroxide in ultrapure water 1 to obtain a sodium hydroxide solution; dissolving vermiculite, cobalt salt, and manganese salt in ultrapure water 2, then dropping the sodium hydroxide solution into the solution, heating to react, and filtering to obtain a precipitate; washing, drying, grinding, and sieving the precipitate in sequence to obtain a precursor;

[0009] (2) calcining the precursor to obtain a vermiculite-loaded cubic cobalt manganese spinel material (VT@CM);

[0010] (3) dissolving hexadecyltrimethylammonium bromide in ultrapure water, then adding the vermiculite-loaded cubic cobalt manganese spinel material, stirring, and obtaining a precipitate;

[0011] (4) The precipitate is washed, dried, ground and sieved in sequence to obtain a modified vermiculite-loaded cubic cobalt manganese spinel material (C-VT@CM).

[0012] Furthermore, in step (1),

[0013] The dosage ratio of the sodium hydroxide and ultrapure water 1 is (0.3-0.6) g: (5-10) mL; and / or,

[0014] The amount ratio of the sodium hydroxide, vermiculite, cobalt salt, manganese salt and ultrapure water 2 is (0.3-0.6) g: (5-10) g: (0.7-1.4) g: (0.3-0.6) g: (55-110) mL; and / or,

[0015] The cobalt salt is selected from Co(NO3)2•6H2O; and / or,

[0016] The manganese salt is selected from Mn(NO3)2.6H2O; and / or

[0017] The sodium hydroxide solution is added at a rate of 5-10 drops / min; and / or

[0018] The specific operation steps of the heating reaction are: heating at 160-180° C. for 8-15 hours; and / or,

[0019] The specific operation steps of the washing are: washing with deionized water and anhydrous ethanol for 2-5 times respectively; and / or,

[0020] The specific operation steps of the drying are: drying at 60-80°C for 12-15h; and / or,

[0021] The grinding and screening is to pass through a 200-mesh sieve.

[0022] Furthermore, in step (2), the specific operation steps of the roasting are: heating to 400-500°C at 10-15°C / min, and keeping at this temperature for 2-3 hours.

[0023] The calcination process removes organic impurities from the material and strengthens the bond between vermiculite and cubic cobalt manganese spinel, enhancing the material's thermal stability and mechanical strength. Furthermore, an appropriate calcination temperature optimizes the material's crystal structure, increasing the number of active sites and improving its ability to activate PMS.

[0024] Furthermore, in step (3),

[0025] The ratio of the vermiculite-loaded cubic cobalt manganese spinel material, hexadecyltrimethylammonium bromide and ultrapure water is (2-5) g: (3-5) g: (80-100) mL; and / or,

[0026] The specific operation steps of the stirring are: stirring at a temperature of 60-80° C. and a stirring rate of 450-600 rpm for 8-12 hours.

[0027] During the modification process, by controlling parameters such as the amount of cetyltrimethylammonium bromide, stirring temperature and rate, it is possible to ensure that cetyltrimethylammonium bromide is evenly dispersed on the surface of the material, thereby achieving effective modification of the material surface.

[0028] Furthermore, in step (4),

[0029] The specific operation steps of the washing are: washing with deionized water and anhydrous ethanol for 2-5 times respectively; and / or,

[0030] The specific operation steps of the drying are: drying at 60-80°C for 12-15h; and / or,

[0031] The grinding and screening is to pass through a 200-mesh sieve.

[0032] The present invention can remove impurities and maintain the purity and activity of the material through multiple washings and appropriate drying conditions after each preparation step.

[0033] The second object of the present invention is to provide a modified vermiculite-loaded cubic cobalt-manganese spinel material prepared by the above preparation method.

[0034] The third object of the present invention is to provide an application of the modified vermiculite-loaded cubic cobalt manganese spinel material in the degradation of perfluorooctanoic acid in water.

[0035] A fourth object of the present invention is to provide a method for degrading perfluorooctanoic acid in water, comprising the following steps: adding the modified vermiculite-loaded cubic cobalt manganese spinel material, peroxymonosulfate (PMS) and sodium dithionite (DNT) to an aqueous solution containing perfluorooctanoic acid, and then initiating the reaction to achieve degradation of perfluorooctanoic acid.

[0036] The modified vermiculite-loaded cubic cobalt-manganese spinel material can efficiently activate peroxymonosulfate to generate a large amount of sulfate radicals (SO4 •− ) and hydroxyl radicals (•OH). These free radicals have strong oxidizing power and can attack perfluorooctanoic acid molecules, thereby degrading PFOA. Adding sodium dithionite during the degradation process can further improve the reaction efficiency. DNT reacts with PMS to generate more free radicals, enhancing their oxidizing power and thus accelerating the degradation of PFOA.

[0037] Furthermore, the concentration of perfluorooctanoic acid in the aqueous solution is 1 mg / L.

[0038] Furthermore, the usage ratio of the aqueous solution, the modified vermiculite-loaded cubic cobalt manganese spinel material, peroxymonosulfate and sodium dithionite (DNT) is 100 mL: 0.1 g: 0.732 g: 0.1 g.

[0039] Compared with the prior art, the present invention has the following advantages and technical effects:

[0040] The present invention synthesizes vermiculite-loaded cubic cobalt-manganese spinel material through a coprecipitation method, and then modifies the material at a certain temperature to ultimately synthesize the modified vermiculite-loaded cubic cobalt-manganese spinel. The reaction conditions are mild, no toxic or hazardous raw materials are involved, and the prepared material is highly efficient, stable, and environmentally friendly.

[0041] The modified vermiculite-loaded cubic cobalt-manganese spinel material prepared based on the method of the present invention not only has a positive charge on its surface but also has abundant active sites, thereby achieving efficient activation of peroxymonosulfate and efficient degradation of organic pollutants.

[0042] Through the optimized structural design and preparation methods of the present invention, C-VT@CM demonstrates exceptionally high efficiency in degrading PFOA. In experiments, the degradation rate reached 93.3% within 120 minutes, significantly exceeding that of unmodified cobalt-manganese spinel. Furthermore, the material exhibits excellent stability during the reaction, exhibiting no significant structural changes or activity loss, and is reusable, demonstrating high practical application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The accompanying drawings, which constitute part of the present invention, are provided to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are provided to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0044] Figure 1 The scanning electron microscopy characterization results of the modified vermiculite-loaded cubic cobalt-manganese spinel material prepared in Example 1 of the present invention;

[0045] Figure 2 This is the X-ray diffraction pattern of the modified vermiculite-loaded cubic cobalt-manganese spinel material prepared in Example 1 of the present invention;

[0046] Figure 3 X-ray photoelectron spectrum of the modified vermiculite-loaded cubic cobalt-manganese spinel material prepared in Example 1 of the present invention;

[0047] Figure 4 This is a diagram verifying the effect of degrading perfluorooctanoic acid under different conditions of the present invention. DETAILED DESCRIPTION

[0048] 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.

[0049] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between any intermediate value within a stated value or stated range and any other stated value or intermediate value within the stated range is also encompassed by the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0050] 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.

[0051] 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.

[0052] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0053] In this embodiment of the present invention, cubic cobalt-manganese spinel is synthesized by in-situ coprecipitation on the surface and interlayers of vermiculite. The vermiculite-supported cubic cobalt-manganese spinel is then modified using cetyltrimethylammonium bromide to produce a modified vermiculite-supported cubic cobalt-manganese spinel. This reaction is mild and does not involve the use of toxic or hazardous raw materials. The resulting catalyst is stable, efficient, and environmentally friendly, effectively reducing the activation energy of oxidants such as peroxymonosulfate, achieving efficient removal of PFOA.

[0054] The present invention provides a method for preparing a modified vermiculite-loaded cubic cobalt-manganese spinel material, comprising the following steps:

[0055] (1) dissolving sodium hydroxide in ultrapure water 1 to obtain a sodium hydroxide solution; dissolving vermiculite, cobalt salt, and manganese salt in ultrapure water 2 to obtain a mixed solution; dropping the sodium hydroxide solution into the mixed solution to carry out a heating reaction, and filtering to obtain a precipitate; washing, drying, grinding, and sieving the precipitate in sequence to obtain a precursor;

[0056] (2) calcining the precursor to obtain a vermiculite-loaded cubic cobalt manganese spinel material (VT@CM);

[0057] (3) dissolving hexadecyltrimethylammonium bromide in ultrapure water to obtain a hexadecyltrimethylammonium bromide solution, then adding the vermiculite-loaded cubic cobalt manganese spinel material, stirring, and obtaining a precipitate;

[0058] (4) The precipitate is washed, dried, ground and sieved in sequence to obtain a modified vermiculite-loaded cubic cobalt manganese spinel material (C-VT@CM).

[0059] In some optional embodiments of the present invention, in step (1), the usage ratio of the sodium hydroxide and the ultrapure water 1 can be selected as (0.3-0.6) g: (5-10) mL; illustratively, in the following preferred embodiments of the present invention, the usage ratio of the sodium hydroxide and the ultrapure water 1 is 0.3 g: 5 mL.

[0060] In some optional embodiments of the present invention, in step (1), the dosage ratio of the sodium hydroxide, vermiculite, cobalt salt, manganese salt and ultrapure water 2 can be selected as (0.3-0.6) g: (5-10) g: (0.7-1.4) g: (0.3-0.6) g: (55-110) mL; illustratively, in the following preferred embodiments of the present invention, the dosage ratio of the sodium hydroxide, vermiculite, cobalt salt, manganese salt and ultrapure water 2 is 0.3 g: 5 g: 0.7 g: 0.3 g: 55 mL.

[0061] The ultrapure water 1 and the ultrapure water 2 in step (1) of the present invention are both ultrapure water. The marks 1 and 2 are for distinguishing that the two waters are used to prepare different solutions and have no limiting effect on the properties of the water.

[0062] In the following preferred embodiments of the present invention, in step (1), the cobalt salt is selected from Co(NO3)2•6H2O.

[0063] In the following preferred embodiments of the present invention, in step (1), the manganese salt is selected from Mn(NO3)2•6H2O.

[0064] In some optional embodiments of the present invention, in step (1), the dripping speed of the sodium hydroxide solution can be selected to be 5-10 drops / min; illustratively, in the following preferred embodiments of the present invention, the dripping speed of the sodium hydroxide solution is 5 drops / min.

[0065] In some optional embodiments of the present invention, in step (1), the specific operation step of the heating reaction can be selected as follows: heating at 160-180°C for 8-15 hours. For example, in the following preferred embodiments of the present invention, the heating is heating at 160°C for 8 hours.

[0066] In some optional embodiments of the present invention, in step (1), the specific operation steps of the washing can be selected as follows: washing with deionized water and anhydrous ethanol for 2-5 times respectively; illustratively, in the following preferred embodiments of the present invention, washing with deionized water and anhydrous ethanol for 3 times respectively.

[0067] In some optional embodiments of the present invention, in step (1), the specific operation steps of the drying can be selected as: drying at 60-80°C for 12-15 hours; illustratively, in the following preferred embodiments of the present invention, the drying is drying at 60°C for 12 hours.

[0068] In the following preferred embodiment of the present invention, in step (1), the grinding and screening is through a 200-mesh sieve.

[0069] In some optional embodiments of the present invention, in step (2), the specific operation steps of the roasting can be selected as follows: heating to 400-500°C at 10-15°C / min and keeping at this temperature for 2-3 hours; illustratively, in the following preferred embodiments of the present invention, the roasting is heating to 450°C at 10°C / min and keeping at this temperature for 2 hours.

[0070] In some optional embodiments of the present invention, in step (3), the usage ratio of the vermiculite-loaded cubic cobalt manganese spinel material, hexadecyltrimethylammonium bromide and ultrapure water can be selected as (2-5) g: (3-5) g: (80-100) mL; illustratively, in the following preferred embodiments of the present invention, the usage ratio of the vermiculite-loaded cubic cobalt manganese spinel material, hexadecyltrimethylammonium bromide and ultrapure water is 4 g: 4.6 g: 80 mL.

[0071] In some optional embodiments of the present invention, in step (3), the stirring operation step may be: stirring at a temperature of 60-80°C and a stirring rate of 450-600 rpm for 8-12 hours. For example, in the following preferred embodiments of the present invention, the stirring operation step is stirring at a temperature of 65°C and a stirring rate of 600 rpm for 12 hours.

[0072] In some optional embodiments of the present invention, in step (4), the specific operation steps of the washing can be selected as follows: washing with deionized water and anhydrous ethanol for 2-5 times respectively; illustratively, in the following preferred embodiments of the present invention, washing with deionized water and anhydrous ethanol for 3 times respectively.

[0073] In some optional embodiments of the present invention, in step (4), the specific operation steps of the drying can be selected as: drying at 60-80°C for 12-15 hours; illustratively, in the following preferred embodiments of the present invention, the drying is drying at 60°C for 12 hours.

[0074] In the following preferred embodiment of the present invention, in step (4), the grinding and screening is through a 200-mesh sieve.

[0075] A modified vermiculite-loaded cubic cobalt-manganese spinel material can be prepared by the above preparation method.

[0076] The modified vermiculite-loaded cubic cobalt manganese spinel material can be used to degrade perfluorooctanoic acid in water.

[0077] An embodiment of the present invention also provides a method for degrading perfluorooctanoic acid in water, comprising the following steps: adding the modified vermiculite-loaded cubic cobalt manganese spinel material, peroxymonosulfate and sodium dithionite to an aqueous solution containing perfluorooctanoic acid, and then initiating the reaction to achieve degradation of perfluorooctanoic acid.

[0078] In the following preferred embodiments of the present invention, the concentration of perfluorooctanoic acid in the aqueous solution is 1 mg / L.

[0079] In the following preferred embodiments of the present invention, the usage ratio of the aqueous solution, the modified vermiculite-loaded cubic cobalt manganese spinel material, peroxymonosulfate and sodium dithionite is 100 mL: 0.1 g: 0.732 g: 0.1 g.

[0080] Unless otherwise specified, the "room temperature" in the present invention refers to 23-25°C.

[0081] The raw materials used in the present invention are all purchased from the market.

[0082] The technical solution of the present invention is further illustrated by the following examples.

[0083] Example 1

[0084] A method for preparing a modified vermiculite-loaded cubic cobalt-manganese spinel material comprises the following steps:

[0085] (1) Dissolve 0.3 g of sodium hydroxide in 5 mL of ultrapure water at 25°C to obtain a sodium hydroxide solution;

[0086] (2) Dissolve 5 g of vermiculite, 0.7 g of Co(NO3)2•6H2O, and 0.3 g of Mn(NO3)2•6H2O in 55 mL of ultrapure water at 25°C to obtain a mixed solution;

[0087] (3) slowly adding the sodium hydroxide solution of step (1) to the mixed solution of step (2) at a rate of 5 drops / min at 25° C. to obtain a mixture;

[0088] (4) The mixture from step (3) was transferred to a reactor, placed in a forced air drying oven, heated at 160°C for 8 h, cooled to 25°C, and filtered to obtain a precipitate;

[0089] (5) The precipitate obtained in step (4) was washed three times with deionized water and anhydrous ethanol respectively, and then vacuum dried at 60°C for 12 hours, and ground through a 200-mesh sieve to obtain a vermiculite-loaded cubic cobalt manganese spinel material precursor;

[0090] (6) The precursor material of step (5) was heated to 450°C at 10°C / min, calcined at the temperature for 2 h, and then cooled to room temperature to obtain vermiculite-loaded cubic cobalt manganese spinel material (VT@CM);

[0091] (7) Dissolve 4.6 g of hexadecyltrimethylammonium bromide (CTAB) in 80 mL of ultrapure water at 25 °C, evenly disperse 4 g of VT@CM prepared in step (6) in the CTAB solution, heat and stir at 65 °C and 600 rpm for 12 h, and then cool to room temperature to obtain a precipitate;

[0092] (8) The precipitate obtained in step (7) was washed three times with deionized water and anhydrous ethanol, respectively, and then dried in vacuo at 60°C for 12 h, and ground through a 200-mesh sieve to obtain a modified vermiculite-loaded cubic cobalt manganese spinel material (C-VT@CM).

[0093] The material prepared in Example 1 was characterized by scanning electron microscopy, X-ray diffraction patterns, and X-ray photoelectron spectroscopy. Figure 1-3 shown.

[0094] Figure 1 The scanning electron microscope characterization results of the modified vermiculite-loaded cubic cobalt-manganese spinel material prepared in Example 1 of the present invention; Figure 1 It can be seen that the microstructure of the prepared modified vermiculite loaded cubic cobalt manganese spinel presents a lamellar structure, with cubic cobalt manganese spinel nanoparticles attached to the surface and between layers, indicating that the material has been successfully synthesized.

[0095] Figure 2 The X-ray diffraction pattern of the modified vermiculite-loaded cubic cobalt-manganese spinel material prepared in Example 1 of the present invention; Figure 2 It can be seen that the structure of the prepared modified vermiculite-loaded cubic cobalt manganese spinel contains not only the characteristic peaks of vermiculite, but also the characteristic peaks of cubic cobalt manganese spinel nanoparticles, indicating that the material has been successfully synthesized.

[0096] Figure 3 X-ray photoelectron spectrum of the modified vermiculite-loaded cubic cobalt-manganese spinel material prepared in Example 1 of the present invention; Figure 3 It can be seen that the characteristic elements of the prepared modified vermiculite-loaded cubic cobalt manganese spinel not only contain the Si element of vermiculite, but also contain the Co, Mn, and O elements of cubic cobalt manganese spinel nanoparticles, indicating that the material has been successfully synthesized.

[0097] Comparative Example 1

[0098] A method for preparing a cobalt-manganese spinel material comprises the following steps:

[0099] (1) Dissolve 0.3 g of sodium hydroxide in 5 mL of ultrapure water at 25°C to obtain a sodium hydroxide solution;

[0100] (2) Dissolve 0.7 g of Co(NO3)2•6H2O and 0.3 g of Mn(NO3)2•6H2O in 55 mL of ultrapure water at 25°C to obtain a mixed solution;

[0101] (3) slowly adding the sodium hydroxide solution of step (1) to the mixed solution of step (2) at a rate of 5 drops / min at 25° C. to obtain a mixture;

[0102] (4) The mixture from step (3) was transferred to a reactor, placed in a forced air drying oven, heated at 160°C for 8 h, cooled to 25°C, and filtered to obtain a precipitate;

[0103] (5) The precipitate obtained in step (4) was washed three times with deionized water and anhydrous ethanol respectively, then dried under vacuum at 60°C for 12 h, and ground through a 200-mesh sieve to obtain a precursor;

[0104] (6) The precursor material of step (5) was heated to 450°C at 10°C / min, calcined at the same temperature for 2 h, and then cooled to room temperature to obtain a cobalt-manganese spinel material (CM).

[0105] Application Example 1

[0106] A method for degrading perfluorooctanoic acid (PFOA) in water by activating peroxymonosulfate with sodium dithionite:

[0107] Experimental Group 1:

[0108] 100 mL of 1 mg / L PFOA solution was added to a conical flask, and 0.1 g of C-VT@CM prepared in Example 1, 0.732 g of permonosulfate (PMS), and 0.1 g of sodium dithionite (DNT) were added to the system to start the reaction. 1.0 mL of the reaction solution was collected at the set time (120 min), filtered using a nylon syringe filter, and 0.5 mL of the reaction solution was quickly added to a brown vial containing 1.5 mL of sodium thiosulfate solution. The test results are shown in Figure 2. Figure 4 shown.

[0109] Experimental Group 2:

[0110] 100 mL of 1 mg / L PFOA solution was added to a conical flask, and 0.1 g of C-VT@CM prepared in Example 1 and 0.732 g of peroxymonosulfate (PMS) were added to the system to start the reaction. 1.0 mL of the reaction solution was collected at the set time (120 min), filtered using a nylon syringe filter, and 0.5 mL of the reaction solution was quickly added to a brown vial containing 1.5 mL of sodium thiosulfate solution. The test results are shown in Figure 2. Figure 4 shown.

[0111] Experimental group three:

[0112] 100 mL of 1 mg / L PFOA solution was added to a conical flask, and 0.1 g of CM prepared in Comparative Example 1, 0.732 g of permonosulfate (PMS), and 0.1 g of sodium dithionite (DNT) were added to the system to start the reaction. 1.0 mL of the reaction solution was collected at the set time (120 min), filtered using a nylon syringe filter, and 0.5 mL of the reaction solution was quickly added to a brown vial containing 1.5 mL of sodium thiosulfate solution. The test results are as follows: Figure 4 shown.

[0113] Figure 4 This is the effect verification diagram of the degradation of perfluorooctanoic acid in experimental group 1, experimental group 2 and experimental group 3. Figure 4 Test results show that the C-VT@CM prepared in Example 1 can effectively activate permonosulfate in conjunction with sodium dithionite to degrade PFOA in water, achieving a PFOA degradation rate of 93.3% within 120 minutes. The CM prepared in Comparative Example 1 only achieved a PFOA degradation rate of 20.53% within 120 minutes. This is because the CM cannot rapidly accumulate PFOA on the catalyst surface, increasing the resistance to the degradation reaction.

[0114] Experimental group 4

[0115] A 100 mL 1 mg / L PFOA solution was added to a conical flask. To initiate the reaction, 0.1 g of C-VT@CM prepared in Example 1, 0.366 g of permonosulfate (PMS), and 0.1 g of sodium dithionite (DNT) were added to the system. At the set time (120 min), 1.0 mL of the reaction solution was collected and filtered through a nylon syringe filter. After that, 0.5 mL of the reaction solution was quickly added to a brown vial containing 1.5 mL of sodium thiosulfate solution.

[0116] The results showed that the degradation rate of perfluorooctanoic acid was 65.24% within 120 minutes.

[0117] Experimental Group 5

[0118] A 100 mL 1 mg / L PFOA solution was added to a conical flask. The reaction was initiated by adding 0.1 g of C-VT@CM prepared in Example 1, 1.464 g of permonosulfate (PMS), and 0.1 g of sodium dithionite (DNT). At the set time (120 min), 1.0 mL of the reaction solution was collected and filtered through a nylon syringe filter. After that, 0.5 mL of the reaction solution was quickly added to a brown vial containing 1.5 mL of sodium thiosulfate solution.

[0119] The results showed that the degradation rate of perfluorooctanoic acid was 79.64% within 120 minutes.

[0120] Experimental Group 6

[0121] A 100 mL 1 mg / L PFOA solution was added to a conical flask. The reaction was initiated by adding 0.1 g of C-VT@CM prepared in Example 1, 0.732 g of permonosulfate (PMS), and 0.05 g of sodium dithionite (DNT). At the set time (120 min), 1.0 mL of the reaction solution was collected and filtered through a nylon syringe filter. After that, 0.5 mL of the reaction solution was quickly added to a brown vial containing 1.5 mL of sodium thiosulfate solution.

[0122] The results showed that the degradation rate of perfluorooctanoic acid was 49.36% within 120 minutes.

[0123] Experimental Group 7

[0124] A 100 mL 1 mg / L PFOA solution was added to a conical flask. The reaction was initiated by adding 0.1 g of C-VT@CM prepared in Example 1, 0.732 g of permonosulfate (PMS), and 0.15 g of sodium dithionite (DNT). At the set time (120 min), 1.0 mL of the reaction solution was collected and filtered through a nylon syringe filter. After that, 0.5 mL of the reaction solution was quickly added to a brown vial containing 1.5 mL of sodium thiosulfate solution.

[0125] The results showed that the degradation rate of perfluorooctanoic acid was 83.12% within 120 minutes.

[0126] Comparative Example 2

[0127] A method for preparing a vermiculite-loaded cubic cobalt-manganese spinel material comprises the following steps:

[0128] (1) Dissolve 0.3 g of sodium hydroxide in 5 mL of ultrapure water at 25°C to obtain a sodium hydroxide solution;

[0129] (2) Dissolve 5 g of vermiculite, 0.7 g of Co(NO3)2•6H2O, and 0.3 g of Mn(NO3)2•6H2O in 55 mL of ultrapure water at 25°C to obtain a mixed solution;

[0130] (3) slowly adding the sodium hydroxide solution of step (1) to the mixed solution of step (2) at a rate of 5 drops / min at 25° C. to obtain a mixture;

[0131] (4) The mixture from step (3) was transferred to a reactor, placed in a forced air drying oven, heated at 160°C for 8 h, cooled to 25°C, and filtered to obtain a precipitate;

[0132] (5) The precipitate obtained in step (4) was washed three times with deionized water and anhydrous ethanol respectively, and then vacuum dried at 60°C for 12 hours, and ground through a 200-mesh sieve to obtain a vermiculite-loaded cubic cobalt manganese spinel material precursor;

[0133] (6) The precursor material of step (5) was heated to 450°C at 10°C / min, calcined at the same temperature for 2 h, and then cooled to room temperature to obtain vermiculite-loaded cubic cobalt manganese spinel material (VT@CM).

[0134] Using the same test method as Application Example 1, it was found that the degradation rate of perfluorooctanoic acid was 48.95% within 120 minutes.

[0135] Comparative Example 3

[0136] Same as Example 1, except that the mass of hexadecyltrimethylammonium bromide in step (7) is replaced by polyfluoroalkyl quaternary ammonium salt (PFQA).

[0137] Using the same test method as Application Example 1, it was found that the degradation rate of perfluorooctanoic acid was 36.52% within 120 minutes.

[0138] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for preparing a modified vermiculite-loaded cubic cobalt-manganese spinel material, characterized in that: The specific steps include: (1) dissolving sodium hydroxide in ultrapure water 1 to obtain a sodium hydroxide solution; dissolving vermiculite, cobalt salt and manganese salt in ultrapure water 2, then dropping the sodium hydroxide solution into the solution, heating to react, and filtering to obtain a precipitate; washing, drying, grinding and sieving the precipitate in sequence to obtain a precursor; the specific operation steps of the heating reaction are: heating at 160-180°C for 8-15 hours; (2) calcining the precursor to obtain a vermiculite-loaded cubic cobalt-manganese spinel material; the specific operation steps of the calcination are: heating to 400-500°C at a rate of 10-15°C / min and keeping the temperature at this temperature for 2-3 hours; (3) dissolving hexadecyltrimethylammonium bromide in ultrapure water, then adding the vermiculite-loaded cubic cobalt manganese spinel material, stirring, and obtaining a precipitate; (4) The precipitate of step (3) is washed, dried, ground and sieved in sequence to obtain a modified vermiculite-loaded cubic cobalt manganese spinel material.

2. The method for preparing the modified vermiculite-loaded cubic cobalt-manganese spinel material according to claim 1, wherein: In step (1), The cobalt salt is selected from Co(NO3)2•6H2O; and / or, The manganese salt is selected from Mn(NO3)2.6H2O; and / or The specific operation steps of the heating reaction are: heating at 160° C. for 8 hours.

3. The method for preparing the modified vermiculite-loaded cubic cobalt-manganese spinel material according to claim 1, wherein: In step (2), the specific operation steps of the roasting are: heating to 450°C at 10°C / min and keeping at this temperature for 2h.

4. The method for preparing the modified vermiculite-loaded cubic cobalt-manganese spinel material according to claim 1, wherein: In step (3), The mass ratio of the vermiculite-loaded cubic cobalt manganese spinel material to cetyltrimethylammonium bromide is 4:4.6; and / or, The specific operation steps of the stirring are: stirring at a temperature of 65° C. and a stirring rate of 600 rpm for 12 hours.

5. The method for preparing the modified vermiculite-loaded cubic cobalt-manganese spinel material according to claim 1, wherein: In step (4), The specific operation steps of the drying are: drying at 60°C for 12 hours; and / or, The grinding and screening is to pass through a 200-mesh sieve.

6. A modified vermiculite-loaded cubic cobalt-manganese spinel material prepared by the preparation method according to any one of claims 1 to 5.

7. Use of the modified vermiculite-loaded cubic cobalt-manganese spinel material according to claim 6 in the degradation of perfluorooctanoic acid in water, characterized in that: The following steps are involved: The modified vermiculite-loaded cubic cobalt manganese spinel material, peroxymonosulfate and sodium dithionite are added to an aqueous solution containing perfluorooctanoic acid, and the reaction is initiated to achieve degradation of the perfluorooctanoic acid.

8. A method for degrading perfluorooctanoic acid in water, characterized in that: The following steps are involved: The modified vermiculite-loaded cubic cobalt manganese spinel material, peroxymonosulfate and sodium dithionite according to claim 6 are added to an aqueous solution containing perfluorooctanoic acid, and the reaction is initiated to achieve the degradation of perfluorooctanoic acid.

9. The method for degrading perfluorooctanoic acid in water according to claim 8, characterized in that: The concentration of perfluorooctanoic acid in the aqueous solution is 1 mg / L; and / or, The usage ratio of the aqueous solution, the modified vermiculite-loaded cubic cobalt manganese spinel material, peroxymonosulfate and sodium dithionite is 100 mL: 0.1 g: 0.732 g: 0.1 g.

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