CuFe2O4 / Mxene catalyst as well as preparation method and application thereof

Abstract

The invention relates to the technical field of catalytic materials, in particular to a CuFe2O4 / Mxene catalyst and a preparation method and application thereof. The specific preparation method comprises the following steps: dissolving a soluble copper salt and a soluble iron salt in a solvent, adjusting the pH value to 3.5-5.5, removing the solvent to a colloidal state, and calcining to obtain positively charged CuFe2O4; and adding an etching agent into the titanium aluminum carbide for etching to obtain the negatively charged Mxene. The preparation method comprises the following steps: dispersing positively charged CuFe2O4 and negatively charged Mxene in a solvent, and stirring to obtain the CuFe2O4 / Mxene catalyst. The CuFe2O4 / Mxene catalyst disclosed by the invention can be used for effectively activating peroxymonosulfate and rapidly degrading organic pollutants in an aqueous solution, and shows excellent catalytic performance.

Description

Technical Field

[0001] The present invention relates to the technical field of catalytic materials, and particularly to a CuFe2O4 / Mxene catalyst, a preparation method thereof, and an application thereof. Background Art

[0002] Chloroquine phosphate has been widely used in recent years due to its excellent antiviral and anti-inflammatory properties in the medical field. However, with the application research on chloroquine phosphate, it is found that it has high persistence and cumulative effects in the environment, and has toxicity and teratogenicity, which will pose a serious threat to the aquatic ecosystem and human health.

[0003] Due to the stable molecular structure of chloroquine phosphate, traditional water treatment methods, including activated carbon adsorption, biodegradation, and physicochemical oxidation, are difficult to effectively remove or mostly degrade chloroquine phosphate. Therefore, it is urgent to develop an efficient and green technical means to remove the residual chloroquine phosphate pollutants in water.

[0004] Advanced oxidation technology can achieve the deep mineralization of organic pollutants by in-situ generating strongly oxidizing active species. Among them, the advanced oxidation process based on peroxymonosulfate has received extensive attention because it can efficiently generate various reactive oxygen species, including sulfate radical SO4· - , hydroxyl radical ·OH and singlet oxygen 1 O2, and rapidly degrade complex organic pollutants.

[0005] However, the current activation system of peroxymonosulfate usually uses traditional single-component catalysts, which are limited by the defects of low intrinsic conductivity, insufficient electron transfer ability, and uneven distribution of active sites, resulting in low catalytic efficiency and poor stability of the catalyst, restricting its ability to be recycled multiple times and its performance in the treatment of complex pollutants. Summary of the Invention

[0006] In order to solve the technical problems that the single-component catalyst is limited by the defects of low intrinsic conductivity, insufficient electron transfer ability, and uneven distribution of active sites, resulting in low catalytic efficiency and poor stability of the catalyst, the present invention provides a CuFe2O4 / Mxene catalyst, a preparation method thereof, and an application thereof.

[0007] The present invention adopts the sol-gel method. Under acidic conditions, soluble copper salts and soluble iron salts are dispersed in a solvent, and a colloid is obtained by rotary evaporation, and then calcined to obtain spinel-type CuFe₂O₄ with a positive charge; taking titanium aluminum carbide as the matrix, titanium aluminum carbide is chemically etched to remove the aluminum layer in the titanium aluminum carbide, and Mxene with a negative-charged two-dimensional layered structure is obtained; CuFe₂O₄ and Mxene are dispersed in a solvent, and the electrostatic self-assembly method is used to make the positively charged CuFe₂O₄ and the negatively charged Mxene attract each other through electrostatic interaction to form a tight combination, constructing a composite structure with high synergy and uniform distribution, and obtaining a CuFe₂O₄ / Mxene catalyst.

[0008] In the present invention, the Cu atoms and Fe atoms in the CuFe₂O₄ / Mxene catalyst achieve synergy at the nanoscale, significantly increasing the number of active sites of the composite catalyst. At the same time, the spinel structure of CuFe₂O₄ and the two-dimensional layered structure of Mxene form a tight combination, which not only provides rich interfacial active sites, but also promotes the rapid transfer of electrons, enhancing the activation efficiency of peroxymonosulfate in the advanced oxidation process. Moreover, the high conductivity and large specific surface area of Mxene further improve the reaction efficiency of the composite catalyst and provide more reaction space for the generation and migration of active species.

[0009] By optimizing the interfacial interaction, electronic structure and atomic-level coordination environment between CuFe₂O₄ and Mxene, the CuFe₂O₄ / Mxene catalyst exhibits excellent performance in catalytic stability and activity.

[0010] The first object of the present invention is to provide a preparation method of a CuFe₂O₄ / Mxene catalyst, comprising the following steps:

[0011] Dissolve soluble copper salts and soluble iron salts in a solvent, adjust the pH to 3.5 - 5.5, remove the solvent to the colloid state, and then calcine to obtain positively charged CuFe₂O₄.

[0012] Add an etching agent to titanium aluminum carbide for etching to obtain negatively charged Mxene.

[0013] Disperse the positively charged CuFe₂O₄ and the negatively charged Mxene in a solvent, and under the stirring action, make the positively charged CuFe₂O₄ and the negatively charged Mxene attract each other through electrostatic interaction to form a stable interfacial combination, obtaining a CuFe₂O₄ / Mxene catalyst.

[0014] It should be noted that in the present invention, titanium aluminum carbide is introduced as a precursor. After titanium aluminum carbide is etched, the exposed Ti on its surface has uncoordinated d orbitals, which are prone to form -OH and -O functional groups, making MXene have strong negative electronegativity. At the same time, titanium aluminum carbide has a low aluminum layer binding energy, and the atomic bond between the aluminum layer and the adjacent titanium carbide layer is relatively weak, and aluminum atoms are more easily selectively removed by chemical etching agents to obtain a two-dimensional layered structure composed of titanium and carbon atoms; in addition, there are fewer impurities remaining after HF etching, making the negative electronegativity of the etched Mxene more stable.

[0015] Preferably, the mass ratio of the CuFe2O4 to Mxene is 5 to 20:1.

[0016] Preferably, the temperature of the stirring is 60°C to 95°C, and the stirring time is 3h to 6h. This is because during the electrostatic self-assembly process, the positively charged CuFe2O4 and the negatively charged Mxene are attracted to each other through electrostatic interaction, and it takes a certain amount of time for the charge attraction to be stable; in the present invention, a certain amount of stirring is used to improve the activity of the material surface, enhance the interaction between the surface oxide layer of MXene and CuFe2O4, form a more stable self-assembly system, and at the same time maintain the dynamic distribution of the particles to make the adsorption uniform.

[0017] Preferably, the molar ratio of the soluble copper salt to the soluble iron salt is 0.5 mmol to 1 mmol: 0.98 mmol to 2.2 mmol.

[0018] Preferably, the dosage ratio of the titanium aluminum carbide to the etching agent is 3g to 6g: 10mL to 20ml; the concentration of the etching agent is 40%.

[0019] Preferably, the etching agent is hydrofluoric acid.

[0020] In the process of preparing the precursor solution in the present invention, citric acid is added to adjust the pH of the precursor solution, and the pH control range is 3.5 to 5.5; at this pH, the precursor solution is stable and can effectively inhibit the hydrolysis of Fe 3+ and Cu 2+ to ensure the formation of a uniform gel during the rotary evaporation process. At the same time, citric acid, a multidentate ligand, acts as a chelating agent and can form stable chelates with Fe 3+ and Cu 2+ ions to prevent the hydrolysis and precipitation of Fe 3+ and Cu 2+ ions. Moreover, the complexation of citric acid with metal ions helps to uniformly disperse the metal ions in the precursor solution, preventing premature precipitation of metal ions or the formation of non-uniform phases due to excessive local concentration.

[0021] Preferably, the method for removing the solvent is: stirring in a constant temperature water bath at 70 °C to 90 °C for 6 h to 8 h and then drying for 3 h to 5 h.

[0022] Preferably, the calcination method is: calcining at 350 °C to 450 °C for 3 h to 5 h.

[0023] Preferably, the water-soluble copper salt is copper nitrate, copper sulfate, copper chloride or copper acetate.

[0024] Preferably, the water-soluble iron salt is iron nitrate, iron sulfate, iron chloride or iron acetate.

[0025] The second object of the present invention is to provide a CuFe2O4 / Mxene catalyst prepared by the above preparation method.

[0026] The third object of the present invention is to provide the application of the above CuFe2O4 / Mxene catalyst in the degradation of organic pollutants.

[0027] Preferably, the method for degrading organic pollutants is:

[0028] Mixing the CuFe2O4 / Mxene catalyst, peroxymonosulfate and the pollutant solution, and carrying out a catalytic degradation reaction under stirring, and measuring the mass concentration of the pollutant solution after the reaction.

[0029] Preferably, 0.5 g to 2.0 g of the CuFe2O4 / Mxene catalyst is added to each 1 mL of the pollutant solution; 1 g to 65 g of peroxymonosulfate is added to each 1 mL of the pollutant solution.

[0030] Preferably, the mass concentration of the pollutant solution is 20 mg / L to 70 mg / L.

[0031] Preferably, the pH value of the pollutant solution is 3 to 11.

[0032] Preferably, the stirring rate is 300 rpm / min to 500 rpm / min, and the stirring time is 30 min to 60 min.

[0033] Preferably, the pollutants include chloroquine phosphate, norfloxacin, oxytetracycline and tetracycline.

[0034] Compared with the prior art, the present invention has the following technical effects:

[0035] 1. In the present invention, positively charged CuFe2O4 and negatively charged Mxene are attracted to each other through electrostatic interaction, enabling the spinel structure of CuFe2O4 to form a tight combination with the two-dimensional layered structure of Mxene, thereby constructing a composite structure with high synergy and uniform distribution. This not only provides abundant interfacial active sites but also promotes the rapid transfer of electrons, enhancing the activation efficiency of peroxymonosulfate in the advanced oxidation process. At the same time, the synergistic effect of Cu atoms and Fe atoms in the CuFe2O4 / Mxene catalyst is achieved at the nanoscale, significantly increasing the number of active sites of the composite catalyst. Moreover, the high conductivity and large specific surface area of Mxene further improve the reaction efficiency of the composite catalyst. This solves the technical problems that single-component catalysts are limited by low intrinsic conductivity, insufficient electron transfer ability, and uneven distribution of active sites, resulting in low catalytic efficiency and poor stability of the catalyst.

[0036] 2. The CuFe2O4 / Mxene catalyst prepared in the present invention can rapidly and effectively degrade pollutants in water by activating peroxymonosulfate. Among them, the removal rate of chloroquine phosphate reaches as high as 97.0%, and the degradation rate of tetracycline also reaches 96.3%. The CuFe2O4 / Mxene catalyst effectively activates peroxymonosulfate, and the synergistic effect between the two promotes the rapid transfer of electrons in the system, leading to the degradation of pollutants. In this process, reactive oxygen species with strong oxidation ability are generated in the system, and these reactive oxygen species greatly promote the removal process of chloroquine phosphate and accelerate the overall reaction rate.

[0037] 3. The preparation method of the CuFe2O4 / Mxene catalyst in the present invention is simple in operation and the raw materials are cheap and easily available, thus significantly reducing the production cost. In addition, the obtained CuFe2O4 / Mxene catalyst can maintain the property of being insoluble in water after the catalytic reaction, effectively avoiding any form of secondary pollution to the water body. Moreover, the CuFe2O4 / Mxene catalyst has a stable structure and can be recycled. Description of the Drawings

[0038] Figure 1 SEM images and EDS spectra of the CuFe2O4 / Mxene catalyst prepared in Example 1; among them, (a) is the SEM image at a magnification of 50 μm, (b) is the SEM image at a magnification of 2 μm, (c) is the EDS spectrum of Ti element, (d) is the EDS spectrum of Fe element, and (e) is the EDS spectrum of Cu element.

[0039] Figure 2 Degradation comparison diagrams of the CuFe2O4 catalyst prepared in Comparative Example 1, the Mxene catalyst prepared in Comparative Example 2, and the CuFe2O4 / Mxene catalyst prepared in Example 1.

[0040] Figure 3 Results graph of the degradation of chloroquine phosphate under different catalytic systems.

[0041] Figure 4 Results graph of the degradation of chloroquine phosphate with different pH values under the activation system of peroxymonosulfate by the CuFe2O4 / Mxene catalyst prepared in Example 1.

[0042] Figure 5 Results graph of the degradation of chloroquine phosphate in the presence of different coexisting anions under the activation system of peroxymonosulfate by the CuFe2O4 / Mxene catalyst prepared in Example 1.

[0043] Figure 6 Results graph of the degradation of chloroquine phosphate in different water qualities under the activation system of peroxymonosulfate by the CuFe2O4 / Mxene catalyst prepared in Example 1.

[0044] Figure 7 LSV graph of the degradation of chloroquine phosphate under the activation system of peroxymonosulfate by the CuFe2O4 / Mxene catalyst prepared in Example 1.

[0045] Figure 8 IT graph of the degradation of chloroquine phosphate under the activation system of peroxymonosulfate by the CuFe2O4 / Mxene catalyst prepared in Example 1. Detailed implementation manners

[0046] In order to enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0047] In the description of the present invention, unless otherwise specified, the reagents used are all commercially available, and the methods used are all conventional techniques in the art.

[0048] Example 1

[0049] This example provides a preparation method of a CuFe2O4 / Mxene catalyst, including the following steps:

[0050] S1. Prepare CuFe2O4:

[0051] Mix 48 ml of deionized water and 2 ml of ethanol to obtain a mixed solvent; dissolve 0.5 mmol of copper nitrate and 1 mmol of iron nitrate in the mixed solvent, and then add 1.5 mmol of anhydrous citric acid to obtain a precursor solution.

[0052] The precursor solution was stirred in a constant temperature water bath at 70 °C for 6 h and then dried in a forced air drying oven at 90 °C for 5 h to form a gel. The gel was placed in a muffle furnace and calcined at 350 °C for 3 h at a heating rate of 5 °C / min to obtain solid CuFe2O4.

[0053] S2. Preparation of Mxene:

[0054] 3.0 g of titanium aluminum carbide was placed in 10 ml of hydrofluoric acid, ultrasonicated for 30 min and then stirred for 24 h to obtain a reaction solution.

[0055] The reaction solution was centrifuged at 9000 rpm for 5 min, washed alternately with deionized water and ethanol 6 times, and dried at 60 °C for 12 h to obtain solid Mxene.

[0056] S3. Preparation of CuFe2O4 / Mxene catalyst:

[0057] CuFe2O4 and Mxene were placed in a 100 mL beaker, 30 ml of water and 20 ml of ethanol were added, stirred in a constant temperature water bath at 60 °C for 8 h, and then dried in a forced air drying oven at 80 °C for 12 h to obtain the CuFe2O4 / Mxene catalyst.

[0058] Example 2

[0059] This example provides a preparation method of CuFe2O4 / Mxene catalyst, including the following steps:

[0060] S1. Preparation of CuFe2O4:

[0061] 35 ml of deionized water and 15 ml of ethanol were mixed to obtain a mixed solvent. 1 mmol of copper nitrate and 2 mmol of iron nitrate were dissolved in the mixed solvent, and then 3 mmol of anhydrous citric acid was added to obtain a precursor solution.

[0062] The precursor solution was stirred in a constant temperature water bath at 85 °C for 6 h and then dried in a forced air drying oven at 85 °C for 4 h to form a gel. The gel was placed in a muffle furnace and calcined at 400 °C for 4 h at a heating rate of 5 °C / min to obtain solid CuFe2O4.

[0063] S2. Preparation of Mxene:

[0064] 6.0 g of titanium aluminum carbide was placed in 20 ml of hydrofluoric acid, ultrasonicated for 30 min and then stirred for 24 h to obtain a reaction solution.

[0065] The reaction solution was centrifuged at 8000 rpm for 3 min, washed alternately with deionized water and ethanol 6 times, and dried at 60 °C for 12 h to obtain solid Mxene.

[0066] S2. Preparation of CuFe2O4 / Mxene catalyst:

[0067] Place CuFe2O4 and Mxene in a 100 mL beaker, add 40 ml of water and 10 ml of ethanol, stir in a 60 °C constant temperature water bath for 8 h, and then dry in a 80 °C forced air drying oven for 12 h to obtain the CuFe2O4 / Mxene catalyst.

[0068] Example 3

[0069] This example provides a preparation method of CuFe2O4 / Mxene catalyst, including the following steps:

[0070] S1. Preparation of CuFe2O4:

[0071] Mix 40 ml of deionized water and 10 ml of ethanol to obtain a mixed solvent; dissolve 0.5 mmol of copper nitrate and 0.98 mmol of iron nitrate in the mixed solvent, and then add 1.48 mmol of anhydrous citric acid to obtain a precursor solution.

[0072] Stir the precursor solution in a 75 °C constant temperature water bath for 6 h and then dry in a 75 °C forced air drying oven for 5 h to form a gel; place the gel in a muffle furnace and heat it at a heating rate of 5 °C / min to 450 °C and calcine for 3 h to obtain solid CuFe2O4.

[0073] S2. Preparation of Mxene:

[0074] Place 4.0 g of titanium aluminum carbide in 20 ml of hydrofluoric acid, ultrasonically treat for 30 min and then stir for 24 h to obtain a reaction solution.

[0075] Centrifuge the reaction solution at a speed of 9000 rpm for 10 min, and wash it alternately with deionized water and ethanol 6 times, and dry at 60 °C for 12 h to obtain solid Mxene.

[0076] S2. Preparation of CuFe2O4 / Mxene catalyst:

[0077] Place CuFe2O4 and Mxene in a 100 mL beaker, add 45 ml of water and 5 ml of ethanol, stir in a 60 °C constant temperature water bath for 8 h, and then dry in a 80 °C forced air drying oven for 12 h to obtain the CuFe2O4 / Mxene catalyst.

[0078] Example 4

[0079] This example provides a preparation method of CuFe2O4 / Mxene catalyst, including the following steps:

[0080] S1. Preparation of CuFe₂O₄:

[0081] Mix 42 ml of deionized water and 8 ml of ethanol to obtain a mixed solvent; dissolve 1 mmol of copper nitrate and 2.2 mmol of iron nitrate in the mixed solvent, and then add 2.2 mmol of anhydrous citric acid to obtain a precursor solution.

[0082] Stir the precursor solution in a constant temperature water bath at 82 °C for 8 h and then dry it in a forced air drying oven at 80 °C for 5 h to form a gel; place the gel in a muffle furnace and heat it to 450 °C at a heating rate of 5 °C / min and calcine it for 4 h to obtain solid CuFe₂O₄.

[0083] S2. Preparation of Mxene:

[0084] Place 4.0 g of titanium aluminum carbide in 20 ml of hydrofluoric acid, ultrasonically treat it for 30 min and then stir it for 24 h to obtain a reaction solution.

[0085] Centrifuge the reaction solution at a speed of 8500 rpm for 5 min, wash it alternately with deionized water and ethanol 6 times, and dry it at 60 °C for 12 h to obtain solid Mxene.

[0086] S3. Preparation of CuFe₂O₄ / Mxene catalyst:

[0087] Place CuFe₂O₄ and Mxene in a 100 mL beaker, add 42 ml of water and 8 ml of ethanol, stir it in a constant temperature water bath at 60 °C for 8 h, and then place it in a forced air drying oven at 80 °C and dry it for 12 h to obtain the CuFe₂O₄ / Mxene catalyst.

[0088] In Examples 1 to 4 of the present invention, the CuFe₂O₄ / Mxene catalyst was successfully prepared, and the surface morphologies were basically the same, and it could degrade organic pollutants in water. Here, the CuFe₂O₄ / Mxene catalyst prepared in Example 1 of the present invention was taken as an example for exploration.

[0089] Comparative Example 1

[0090] This comparative example provides a preparation method of a CuFe₂O₄ catalyst, including the following steps:

[0091] Mix 48 ml of deionized water and 2 ml of ethanol to obtain a mixed solvent; dissolve 0.5 mmol of copper nitrate and 1 mmol of iron nitrate in the mixed solvent, and then add 1.5 mmol of anhydrous citric acid to obtain a precursor solution.

[0092] The precursor solution was stirred in a constant temperature water bath at 70 °C for 6 h and then dried in a forced-air drying oven at 90 °C for 5 h to form a gel. The gel was placed in a muffle furnace and calcined at 350 °C for 3 h at a heating rate of 5 °C / min to obtain the CuFe2O4 catalyst.

[0093] Comparative Example 2

[0094] This comparative example provides a method for preparing the Mxene catalyst, including the following steps:

[0095] 3.0 g of titanium aluminum carbide was placed in 10 ml of hydrofluoric acid, ultrasonicated for 30 min and then stirred for 24 h to obtain a reaction solution.

[0096] The reaction solution was centrifuged at 9000 rpm for 5 min, washed alternately with deionized water and ethanol 6 times, and dried at 60 °C for 12 h to obtain the Mxene catalyst.

[0097] Experimental tests:

[0098] 1. SEM characterization.

[0099] As Figure 1 shown, the CuFe2O4 / Mxene catalyst is formed by stacking small flocculent lamellae into a larger massive structure, which contains a developed porous structure inside. Such pores provide abundant active sites for the adsorption of pollutants and PMS, and at the same time facilitate the smooth progress of the mass transfer process, thus significantly improving the degradation efficiency of the catalyst. The porosity of CuFe2O4 / Mxene also provides an ideal structural support for it to act as a catalyst, showing a relatively high catalytic potential.

[0100] 2. Degradation of chloroquine phosphate under different catalytic systems.

[0101] In the present invention, a chloroquine phosphate solution with a mass concentration of 30 mg / L was prepared using ultrapure water; three portions of the chloroquine phosphate solution were taken and placed in beakers, 30 mL each; 10 mg of the CuFe2O4 / Mxene catalyst and 10 mg of persulfate were added to one portion of the chloroquine phosphate solution; 10 mg of the CuFe2O4 catalyst and 10 mg of persulfate were added to one portion of the chloroquine phosphate solution; 10 mg of the Mxene catalyst and 10 mg of peroxymonosulfate were added to the last portion of the chloroquine phosphate solution. After stirring at 500 r / min for 30 min, the mass concentration of the chloroquine phosphate solution was measured, and the test results are as Figure 2 shown.

[0102] As Figure 2As shown, in the activation system of peroxymonosulfate, when only a single CuFe2O4 catalyst or Mxene catalyst is added, the removal rate of chloroquine phosphate in the solution is low, and it is difficult to degrade. Moreover, the activation effect of a single CuFe2O4 catalyst or Mxene catalyst on persulfate is also not good. However, in the activation system of peroxymonosulfate, the CuFe2O4 / Mxene catalyst can significantly improve the removal rate of chloroquine phosphate.

[0103] In the present invention, a chloroquine phosphate solution with a mass concentration of 30 mg / L is prepared using ultrapure water. Five portions of the chloroquine phosphate solution are respectively placed in beakers, with each portion being 30 mL. 20 mg of the CuFe2O4 / Mxene catalyst is added to one portion of the chloroquine phosphate solution, denoted as Catalyst; 15 mg of peroxymonosulfate is added to one portion of the chloroquine phosphate solution, denoted as PMS; 15 mg of persulfate is added to one portion of the chloroquine phosphate solution, denoted as PDS; 10 mg of the CuFe2O4 / Mxene catalyst and 10 mg of persulfate are added to one portion of the chloroquine phosphate solution, denoted as Catalyst+PDS; 10 mg of the CuFe2O4 / Mxene catalyst and 10 mg of peroxymonosulfate are added to the last portion of the chloroquine phosphate solution, denoted as Catalyst+PMS. After respectively stirring Catalyst, PMS, PDS, Catalyst+PDS, and Catalyst+PMS at 500 r / min for 30 min, the mass concentration of the chloroquine phosphate solution therein is measured, and the test results are as Figure 3 shown.

[0104] As Figure 3 shown, chloroquine phosphate cannot be degraded even when persulfate is used alone, and the activation effect of CuFe2O4 / Mxene on persulfate is not good. However, in the activation system of peroxymonosulfate, the CuFe2O4 / Mxene catalyst can significantly improve the removal rate of chloroquine phosphate; adding only the CuFe2O4 / Mxene catalyst cannot achieve the degradation effect on chloroquine phosphate, which proves that the single CuFe2O4 / Mxene catalyst cannot rapidly remove chloroquine phosphate. Therefore, in the present invention, under the action of peroxymonosulfate, through the combined use of the CuFe2O4 / Mxene catalyst and PMS, the degradation effect on chloroquine phosphate is the best, and the removal rate reaches 97.0%. This is because the CuFe2O4 / Mxene catalyst has an activation effect on peroxymonosulfate, can generate a variety of strong oxidizing substances, increases the concentration of free radicals and non-free radicals in the chloroquine phosphate solution, acts on chloroquine phosphate together, promotes its removal, and accelerates the progress of the reaction.

[0105] Based on this, the present invention combines the CuFe2O4 / Mxene catalyst and peroxymonosulfate for synergistic enhancement to remove various organic pollutants including norfloxacin, oxytetracycline, and tetracycline. In addition, the system in which the CuFe2O4 / Mxene catalyst activates peroxymonosulfate is denoted as CuFe2O4 / Mxene / PMS.

[0106] 3. Degrade chloroquine phosphate under different pH systems.

[0107] Take 6 portions of chloroquine phosphate solutions with a mass concentration of 30 mg / L and place them in beakers, 30 mL for each portion; adjust the pH values of the 6 portions of chloroquine phosphate solutions to 2, 3, 5, 7, 9, and 11 respectively; then add 20 mg of the CuFe2O4 / Mxene catalyst and 15 mg of peroxymonosulfate to the chloroquine phosphate solutions with different pH values, stir at 500 r / min for 40 min, and measure the mass concentration of the chloroquine phosphate solution therein. The test results are as Figure 4 shown.

[0108] As Figure 4 shown, after changing the pH value of the chloroquine phosphate solution, the removal efficiency of chloroquine phosphate is affected differently. Under the extremely acidic condition of pH = 2, the degradation effect of chloroquine phosphate is inhibited; under the weakly acidic condition of pH > 5 and the alkaline condition of pH > 7, the degradation rate of chloroquine phosphate increases significantly. In summary, the interfacial effect of the CuFe2O4 / Mxene catalyst promotes the degradation of chloroquine phosphate, especially more significantly under neutral and alkaline pH conditions.

[0109] 4. Degrade chloroquine phosphate in the presence of different anions.

[0110] Take 6 portions of chloroquine phosphate solutions with a mass concentration of 30 mg / L and place them in beakers, 30 mL for each portion; adjust the chloroquine phosphate solutions to contain 10 mM of H2PO4 - , 10 mM of Cl - , 10 mM of CO3 2- , 10 mM of SO4 2- and 10 mM of HCO3 - , with one portion as a blank control group denoted as Blank; then add 20 mg of the CuFe2O4 / Mxene catalyst and 15 mg of peroxymonosulfate to the chloroquine phosphate solutions with different anion concentrations and the solution of the blank control group respectively, stir at a stirring rate of 500 r / min for 40 min, and measure the mass concentration of the chloroquine phosphate solution therein; the test results are as Figure 5 shown. The system of mixing the CuFe2O4 / Mxene catalyst and peroxymonosulfate is denoted as CuFe2O4 / Mxene / PMS.

[0111] As Figure 5 shown, CO3 2- and HCO3 - promoted the degradation of chloroquine phosphate in the CuFe2O4 / Mxene / PMS system. When SO4 2- and Cl - were introduced into the CuFe2O4 / Mxene / PMS system, the degradation of chloroquine phosphate was less affected. Further, when H2PO4 - was added, the degradation process of chloroquine phosphate was significantly blocked. This indicates that the presence of SO4 2- , Cl - and H2PO4 - all had an inhibitory effect on the degradation of chloroquine phosphate.

[0112] 5. Degrade chloroquine phosphate in different water qualities.

[0113] Tap water, Ningdong groundwater, Shahu surface water and Zhongwei section of the Yellow River water were used as solvents respectively to prepare 4 kinds of chloroquine phosphate solutions with a mass concentration of 40 mg / L; 30 mL of chloroquine phosphate solutions prepared with different solvents were measured and placed in different beakers respectively; then 20 mg of CuFe2O4 / Mxene catalyst and 15 mg of peroxymonosulfate were added to the chloroquine phosphate solutions prepared with different solvents respectively. After stirring at 500 r / min for 40 min, the mass concentration of the chloroquine phosphate solution was measured, and the test results are as Figure 6 shown.

[0114] As Figure 6 shown, in the peroxymonosulfate system, the synergistic effect of the CuFe2O4 / Mxene catalyst and peroxymonosulfate showed good stability in the chloroquine phosphate solutions prepared with different water qualities. Even under complex water quality conditions, the degradation rate of chloroquine phosphate could reach about 97%.

[0115] In summary, in the peroxymonosulfate system, the CuFe2O4 / Mxene catalyst is not only highly practical but also has good environmental adaptability, providing strong support for its application in wastewater treatment processes.

[0116] 6. Degrade other pollutants.

[0117] Taking the CuFe2O4 / Mxene catalyst prepared in Example 1 as an example, it is applied to the removal of other pollutants, including norfloxacin, oxytetracycline or tetracycline, and the removal effect is explored. The specific application method is as follows: Take 20 mg of the CuFe2O4 / Mxene catalyst and mix it with 15 mg of peroxymonosulfate, denoted as CuFe2O4 / Mxene / PMS; Mix CuFe2O4 / Mxene / PMS with 30 mL of a pollutant solution with a mass concentration of 40 mg / L respectively to obtain a test solution; Take 2 mL of the test solution sample every 5 minutes, that is, CuFe2O4 / PMS / pollutant, and the pollutant is ofloxacin, oxytetracycline or tetracycline; And filter it through a 0.22 μm aqueous filter membrane. Then use high performance liquid chromatography to detect the concentration of the remaining pollutants in the solution sample. The specific test method is as follows:

[0118] When the pollutant is ofloxacin, the high performance liquid chromatography system is carried out on a Waters 2695 diode array detector. The measured concentration is the remaining mass concentration of norfloxacin after degradation, and the detection wavelength is 280 nm. The instrument parameters are: The chromatographic column is: HC-C18 InertSustain, 4.6 mm×150 mm, 5 μm, and separation is carried out under the mobile phase conditions composed of tetrabutylammonium bromide solution and acetonitrile. The volume ratio of the tetrabutylamine mixture to the tetrabutylammonium bromide solution and acetonitrile is 94:6, and the flow rate is 0.9 mL / min.

[0119] When the pollutant is oxytetracycline, the high performance liquid chromatography system is carried out on a Waters 2695 diode array detector. The measured concentration is the residual mass concentration of oxytetracycline after degradation, and the detection wavelength is 357 nm. The instrument parameters are: The chromatographic column is: HC-C18 InertSustain, 4.6 mm×150 mm, 5 μm, and the mobile phase is composed of acetonitrile and a 0.1% phosphoric acid solution by mass. The volume ratio of acetonitrile to the phosphoric acid solution is 40:60, and the flow rate is 1 mL / min.

[0120] When the pollutant is tetracycline, the high performance liquid chromatography system is carried out on a Waters 2695 diode array detector. The measured concentration is the remaining mass concentration of norfloxacin after degradation, and the detection wavelength is 358 nm. The instrument parameters are: The chromatographic column is: HC-C18 InertSustain, 4.6 mm×150 mm, 5 μm), and separation is carried out under the mobile phase conditions composed of acetonitrile and methanol. The volume ratio of acetonitrile to methanol is 2:1, and the flow rate is 0.8 mL / min.

[0121] Within 40 min, the removal rate of norfloxacin with an initial mass concentration of 40 mg / L was 89.3%, the removal rate of oxytetracycline with an initial mass concentration of 40 mg / L was 92.5%, and the removal rate of tetracycline with an initial mass concentration of 40 mg / L reached 97.0%.

[0122] This indicates that the CuFe2O4 / Mxene catalyst prepared by the present invention can effectively remove other pollutants, including norfloxacin, oxytetracycline, and tetracycline, and has good removal effects.

[0123] 7. Linear voltammetry test

[0124] The CuFe2O4 / Mxene catalyst was mixed with peroxymonosulfate and denoted as CuFe2O4 / Mxene / PMS; then it was added to the chloroquine phosphate solution for degradation and denoted as CuFe2O4 / Mxene / PMS / CQ.

[0125] As Figure 7 shown, when peroxymonosulfate was added to the CuFe2O4 / Mxene / Na2SO4 system at 120 s, the current in the CuFe2O4 / Mxene / PMS system increased sharply, indicating that peroxymonosulfate interacted with the CuFe2O4 / Mxene catalyst and formed a stable complex CF / Mxene-1@PMS* intermediate. With the addition of chloroquine phosphate, the current in the CuFe2O4 / Mxene / PMS / CQ system increased more significantly, indicating that electron transfer could occur in the coexistence state of the three substances.

[0126] As Figure 8 shown, when peroxymonosulfate was added at 120 s, a rapid negative current would be generated in the CuFe2O4 / Mxene / PMS system, which might be due to the disruption of the potential balance caused by the presence of the CF / Mxene-1@PMS* intermediate; after adding chloroquine phosphate, the current showed a significant jump because it could provide electrons to the CF / Mxene-1@PMS* intermediate. The above electrochemical tests provided strong support for the existence of a large amount of electron transfer in the system.

[0127] It should be noted that when the present invention involves numerical ranges, it should be understood that any value between the two endpoints of each numerical range and the two endpoints can be selected. Since the adopted step methods are the same as those in the embodiments, in order to prevent repetition, the present invention describes the preferred embodiments. Although the preferred embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications to these embodiments once they know the basic creative concept, and these changes and modifications all fall within the scope of the present invention.

[0128] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. If these modifications and variations of the present invention fall within the scope of equivalent technologies of the present invention, the present invention also intends to include these changes and modifications.

Claims

1. Preparation method of CuFe2O4 / Mxene catalyst, characterized in that It includes the following steps: Dissolve soluble copper salt and soluble iron salt in a solvent, adjust the pH to 3.5 - 5.5, remove the solvent until it becomes a colloid state, and then conduct calcination to obtain positively charged CuFe2O4; Add an etchant to titanium aluminum carbide for etching to obtain negatively charged Mxene; Disperse the positively charged CuFe2O4 and the negatively charged Mxene in a solvent. Under the stirring action, make the positively charged CuFe2O4 and the negatively charged Mxene attract each other through electrostatic interaction to form a stable interfacial combination, thereby obtaining the CuFe2O4 / Mxene catalyst.

2. The preparation method of the CuFe2O4 / Mxene catalyst according to claim 1, characterized in that, The mass ratio of the positively charged CuFe2O4 to the negatively charged Mxene is 5 - 20:

1.

3. The preparation method of the CuFe2O4 / Mxene catalyst according to claim 1, wherein, The temperature of the stirring is 60°C - 95°C, and the stirring time is 3h - 6h.

4. The preparation method of the CuFe2O4 / Mxene catalyst according to claim 1, wherein, The molar ratio of the soluble copper salt to the soluble iron salt is 0.5 mmol - 1 mmol:0.98 mmol - 2.2 mmol; The dosage ratio of titanium aluminum carbide to the etchant is 3g - 6g:10mL - 20ml; The mass concentration of the etchant is 40%; The etchant is hydrofluoric acid.

5. The preparation method of the CuFe2O4 / Mxene catalyst according to claim 1, wherein, The method for removing the solvent is: stir in a constant temperature water bath at 70°C - 90°C for 6h - 8h and then dry for 3h - 5h.

6. The preparation method of the CuFe2O4 / Mxene catalyst according to claim 1, characterized in that, The method for calcination is: conduct calcination at 350°C - 450°C for 3h - 5h.

7. A CuFe2O4 / Mxene catalyst, characterized in that, The said CuFe2O4 / Mxene catalyst is prepared by using the preparation method of the CuFe2O4 / Mxene catalyst described in any one of claims 1 - 6.

8. An application of the CuFe2O4 / Mxene catalyst described in claim 7 in degrading organic pollutants.

9. Use of the CuFe2O4 / Mxene catalyst according to claim 8 in degrading organic pollutants, characterized in that, The method for degrading organic pollutants is: Mix the CuFe2O4 / Mxene catalyst, peroxymonosulfate and the pollutant solution, and conduct a catalytic degradation reaction under the stirring action, and measure the mass concentration of the pollutant solution after the reaction; Among them, 0.5g - 2.0g of the CuFe2O4 / Mxene catalyst is added to every 1mL of the pollutant solution; 1g - 65g of peroxymonosulfate is added to every 1mL of the pollutant solution; the mass concentration of the pollutant solution is 20mg / L - 70mg / L.

10. Use of the CuFe2O4 / Mxene catalyst according to claim 9 in the degradation of organic pollutants, characterized in that, The pollutants include chloroquine phosphate, norfloxacin, oxytetracycline and tetracycline.

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