A ternary composite heterogeneous fenton-like catalyst, a preparation method and application thereof

Abstract

The application relates to the technical field of catalysts, in particular to a ternary composite heterogeneous Fenton-like catalyst as well as a preparation method and application thereof. MIL-88A / WS2, CuFe2O4, ethylene glycol and water are mixed and subjected to a hydrothermal reaction to obtain the ternary composite heterogeneous Fenton-like catalyst. The ternary composite heterogeneous Fenton-like catalyst prepared by the application not only overcomes the defects of weak electron conduction capacity, limited pH adaptability and easy agglomeration of CuFe2O4, but also solves the problems of poor catalyst stability, difficult recycling, low PMS utilization rate and low degradation efficiency in the heterogeneous Fenton-like technology.

Description

Technical Field

[0001] This invention relates to the field of catalyst technology, specifically to a ternary composite heterogeneous Fenton catalyst, its preparation method, and its application. Background Technology

[0002] In recent years, the treatment of phenolic wastewater has remained a research focus in the environmental protection field. While traditional methods, such as physical methods like adsorption, membrane separation, coagulation, and extraction, are highly effective, their treatment capacity is limited and they are not suitable for treating high-concentration and large-scale wastewater, thus requiring combination with other technologies. Chemical methods, such as oxidation and electrolysis, offer high treatment efficiency, but their reagents and equipment are expensive. Biological methods are limited by the recalcitrant nature of phenolic compounds, have long treatment cycles, low mineralization rates of pollutants, and sometimes even cause secondary pollution.

[0003] Heterogeneous Fenton-like technologies, as a type of advanced oxidation technology, have improved upon traditional Fenton technology. Due to their high treatment efficiency, relatively low cost, and ease of industrial application, they are gradually becoming one of the main methods in the field of advanced wastewater treatment. In recent years, many foreign scholars have shifted their research focus on heterogeneous Fenton-like technologies from the laboratory to engineering applications, aiming to solve the practical problems of treating recalcitrant organic wastewater. Currently, research on heterogeneous Fenton-like technologies mainly focuses on two aspects: the preparation of heterogeneous catalysts and the transformation of the reaction system. The research on heterogeneous catalysts mainly revolves around the preparation of catalysts containing transition metal ions, while the research on the transformation of the reaction system mainly focuses on the transformation of the oxidant and the alteration of reaction conditions (such as the introduction of electricity and light). These studies have, to varying degrees, solved the problems existing in homogeneous Fenton systems and have practical research significance.

[0004] However, in practical applications, the heterogeneous Fenton process based on persulfate (PMS) still faces many challenges, mainly including: (1) a narrow applicable pH range; (2) the catalyst cannot be recovered and reused; (3) the catalyst structure collapses, resulting in poor stability; (4) low utilization rate of PMS; and (5) Fe 2+ Activate SO4 2- Generate sulfate free radicals (SO4) ·- The rate of ) is low, while Fe 3+ with Fe 2+ The conversion efficiency between them is not ideal; (6) the catalyst is difficult to effectively recover and reuse after the reaction, which is not conducive to environmental protection. Therefore, it is urgent to improve the materials in heterogeneous Fenton technology to reduce the adverse effects in the reaction process and promote the application of Fenton reaction in a wider range of fields.

[0005] Spinel ferrite is widely used in catalytic oxidation due to its useful magnetic recyclability, excellent catalytic performance, high stability, low toxicity and low ion leaching rate. Copper ferrite (CuFe2O4) is a typical spinel material, which has high electron mobility and an effective band gap of 1.6 eV. However, compared with other noble metals, the electron conductivity of single CuFe2O4 is slightly inferior, the pH adaptability is limited, and the agglomeration phenomenon hinders its ability to degrade pollutants. SUMMARY

[0006] In view of the deficiencies in the prior art, the present application provides a ternary composite heterogeneous Fenton-like catalyst, a preparation method and application thereof. The present application obtains a ternary composite heterogeneous Fenton-like catalyst by hydrothermal reaction of MIL-88A / WS2 and CuFe2O4. The present application uses MIL-88A(Fe) as a carrier to effectively disperse WS2 and CuFe2O4, and builds a circulation channel with tungsten ions, iron ions and copper ions among the three, so that the prepared ternary composite heterogeneous Fenton-like catalyst not only successfully overcomes the defects of weak electron conductivity, limited pH adaptability and easy agglomeration of CuFe2O4, but also solves the problems of poor catalyst stability, difficult recycling, low PMS utilization rate and low degradation efficiency in heterogeneous Fenton-like technology, thereby significantly improving the treatment efficiency of phenolic wastewater.

[0007] To achieve the above object, the technical scheme adopted by the present application is as follows:

[0008] The object of the present application is to provide a preparation method of a ternary composite heterogeneous Fenton-like catalyst, comprising the following steps:

[0009] MIL-88A / WS2, CuFe2O4, ethylene glycol and water are mixed and subjected to hydrothermal reaction. In the process of hydrothermal reaction II, CuFe2O4 is loaded on MIL-88A / WS2 to form a chemical bond and build a circulation channel with copper ions, iron ions and tungsten ions, thereby obtaining a ternary composite heterogeneous Fenton-like catalyst. The mass ratio of MIL-88A / WS2, CuFe2O4, ethylene glycol and water is 2:1-8:5:1.

[0010] Preferably, in the preparation of the ternary composite heterogeneous Fenton-like catalyst, the hydrothermal reaction conditions are as follows: reaction at 110-120℃ for 11-12h.

[0011] Preferably, CuFe2O4 is prepared according to the following steps:

[0012] A solution of NaOH is added dropwise to a mixed solution of Cu(NO3)2.3H2O, Fe(NO3)3.9H2O and water, and a coprecipitation reaction is carried out at 85-90°C for 1.5-2 hours, followed by calcination treatment to obtain CuFe2O4; wherein the molar ratio of Cu(NO3)2.3H2O, Fe(NO3)3.9H2O and NaOH is 2.5-3:5-6:300-400.

[0013] Preferably, the preparation steps of MIL-88A / WS2 are as follows:

[0014] WS2, MIL-88A(Fe), ethylene glycol and water are mixed and subjected to a hydrothermal reaction to obtain MIL-88A / WS2, and the MIL-88A / WS2 is a hollow structure; wherein the mass ratio of WS2 to MIL-88A(Fe) is 2:1; when the mass ratio of WS2 to MIL-88A(Fe) is 2:1, the degradation effect of the ternary composite heterogeneous Fenton-like catalyst is optimal; when MIL-88A / WS2, CuFe2O4, ethylene glycol and water are used as raw materials to prepare the ternary composite heterogeneous Fenton-like catalyst, the hollow structure of MIL-88A / WS2 is not damaged due to the selection of the solvent.

[0015] Preferably, in the preparation of MIL-88A / WS2, the hydrothermal reaction conditions are as follows: the reaction is carried out at 110-120°C for 11-12 hours.

[0016] Preferably, the preparation method of MIL-88A(Fe) is as follows:

[0017] FeCl3.6H2O, C4H4O4 and water are mixed and subjected to a hydrothermal reaction at 80-100°C for 11-12 hours to obtain MIL-88A(Fe); wherein the molar ratio of FeCl3.6H2O to C4H4O4 is 1:1; MIL-88A is composed of organic ligands and metal ions; from the crystal structure and chemical composition of MIL-88A, the ideal structure is that iron ions are coordinated and assembled with fumaric acid ligands according to a stoichiometric ratio of 1:1; this molar ratio can ensure that each iron ion is coordinated with a corresponding organic ligand C4H4O4, thereby constructing complete MIL-88A(Fe); if the ratio is higher or lower, part of the iron ions cannot be fully coordinated with the organic ligand C4H4O4, resulting in other impurity phases or unreacted iron ions remaining, which affects the purity and performance of MIL-88A(Fe).

[0018] Preferably, the preparation method of WS2 is as follows:

[0019] The WCl6, thioacetamide and ethanol are mixed, and then the hydrothermal reaction is carried out at 190 DEG C to 200 DEG C for 23h to 24h to obtain WS2; wherein the molar ratio of WCl6 to thioacetamide is 1:6 to 15; within the range, the process of gradually saturating the nanosheet material can be observed.

[0020] The second object of the present application is to provide the ternary composite heterogeneous Fenton-like catalyst prepared by the above preparation method.

[0021] Preferably, in the ternary composite heterogeneous Fenton-like catalyst, the WS2 is coated on the spindle rod-shaped MIL-88A in a nanosheet structure, and the spherical CuFe2O4 is loaded on the nanosheet.

[0022] The third object of the present application is to provide the application of the ternary composite heterogeneous Fenton-like catalyst in the preparation of phenolic wastewater treatment agent.

[0023] Preferably, the application method is:

[0024] The ternary composite heterogeneous Fenton-like catalyst is mixed with a phenol solution, and then the peroxymonosulfate is added under the light-proof condition, and after stirring and reaction, the quencher is added to terminate the reaction; the mass-volume ratio of the ternary composite heterogeneous Fenton-like catalyst, the peroxymonosulfate and the phenol solution is 0.06g to 0.1g:0.1228g:200mL.

[0025] Preferably, the mass concentration of the phenol solution is 20mg / L to 25mg / L.

[0026] Compared with the prior art, the present application has the beneficial effects that:

[0027] 1. The application provides a preparation method of a ternary composite heterogeneous Fenton-like catalyst, wherein MIL-88A / WS2, CuFe2O4, ethylene glycol and water are mixed and subjected to a hydrothermal reaction, in the process of the hydrothermal reaction, CuFe2O4 is loaded on MIL-88A / WS2, the sulfur atoms on the surface of MIL-88A / WS2, the unsaturated Fe and the metal ions of CuFe2O4 interact with each other to form chemical bonds, through the chemical bonds (covalent bond, ionic bond), van der Waals force and hydrogen bond interaction, the interface resistance is reduced, MIL-88A, WS2 and CuFe2O4 are tightly connected, and a circulation channel with copper ions, iron ions and tungsten ions is constructed, the electron transmission efficiency is significantly improved, and the ternary composite heterogeneous Fenton-like catalyst is obtained; the mass ratio of MIL-88A / WS2, CuFe2O4, ethylene glycol and water is 2:1-8:5:1. The ternary composite heterogeneous Fenton-like catalyst prepared by the application has a heterojunction structure between MIL-88A / WS2 and CuFe2O4, not only successfully overcomes the defects of weak electron transmission capacity, limited pH adaptability and easy agglomeration of CuFe2O4, but also solves the problems of poor catalyst stability, difficult recycling, low PMS utilization rate and low degradation efficiency in the heterogeneous Fenton-like technology, thereby significantly improving the treatment efficiency of phenolic wastewater.

[0028] Among them, ethylene glycol and water are used as solvents, the viscosity of ethylene glycol is high, as a dispersant, it can form weak interactions such as hydrogen bonds and van der Waals forces with the surfaces of MIL-88A / WS2 and CuFe2O4, promote the uniform dispersion of CuFe2O4, adjust the viscosity and diffusion rate of the reaction system, and prevent agglomeration. When ethylene glycol, it helps to maintain the stability of the system for a long time, avoids the aggregation and precipitation of MIL-88A / WS2 and CuFe2O4 after collision due to Brownian motion. The addition of water can adjust the overall polarity and viscosity of the system. Water can fine-tune the viscosity of the reaction system, which is beneficial to the full mixing of MIL-88A / WS2 and CuFe2O4, and will not hinder the mutual collision between the ternary composite heterogeneous Fenton-like catalysts due to too large viscosity.

[0029] 2、The ternary composite heterogeneous Fenton-like catalyst has unique ternary metal active sites and a multi-element structure, and fuses the high porosity characteristics of MIL-88A metal-organic framework material (MOFs) and the rich metal sites of the MIL-88A as active sites, the catalytic active sites of the edges and surfaces of WS2 layered material, and the inherent active sites of the CuFe2O4 crystal structure. The compounding of MIL-88A / WS2 and CuFe2O4 not only significantly enhances the number of active sites of the ternary composite heterogeneous Fenton-like catalyst, produces a significant synergistic effect, but also enables the ternary composite heterogeneous Fenton-like catalyst to act on the oxidant, and the multi-element composite structure can provide multiple ways to activate the oxidant, such as by changing the adsorption mode of the oxidant, the electron transfer path, reducing the invalid decomposition of the oxidant, and improving the proportion of the oxidant converted into hydroxyl radicals, thereby enhancing the degradation capacity of pollutants, reducing the treatment cost, and reducing the secondary pollution caused by the un-decomposed oxidant residues.

[0030] 3、The ternary composite heterogeneous Fenton-like catalyst is also applied to wastewater treatment, has a fast reaction rate, a good degradation effect, a wide pH value range, good stability, and strong recycling performance.

[0031] In terms of the reaction rate and the degradation effect, the ternary composite heterogeneous Fenton-like catalyst has better tolerance to various interference components in complex wastewater. Specifically, MIL-88A can remove part of the impurities in the wastewater through adsorption, and WS2 and CuFe2O4 can maintain catalytic activity in a complex chemical environment, thereby improving the pollutant removal effect in actual wastewater treatment.

[0032] In terms of stability and pH value range, the framework structure of MIL-88A (Fe) can physically support WS2 and CuFe2O4, maintain the structural integrity of the ternary composite heterogeneous Fenton-like catalyst, and enable the ternary composite heterogeneous Fenton-like catalyst to maintain a stable physical form during the reaction process. At the same time, the magnetism of CuFe2O4 can play a dispersing role to prevent WS2 from agglomerating. The multi-element structure of the ternary composite heterogeneous Fenton-like catalyst also increases its resistance to chemical changes. In different pH values and oxidation-reduction environments, MIL-88A / WS2 and CuFe2O4 can cooperate with each other to reduce their own chemical changes, thereby prolonging the service life of the ternary composite heterogeneous Fenton-like catalyst.

[0033] In terms of recycling performance, ordinary heterogeneous Fenton-like catalysts are relatively difficult to recycle, but CuFe2O4 has magnetism, so that the ternary composite heterogeneous Fenton-like catalyst can be quickly and efficiently recycled by an external magnetic field. This magnetic recyclable property not only facilitates the reuse of the ternary composite heterogeneous Fenton-like catalyst, reduces the cost, but also effectively prevents the catalyst from flowing into the environment, and reduces the possibility of secondary pollution. Attached Figure Description

[0034] Figure 1 The images shown are SEM and TEM images of MIL-88A(Fe), WS2, MW, CuFe2O4 and MWC-0.1 prepared in Example 1. Among them, (a) is the SEM image of MIL-88A(Fe), (b) is the SEM image of WS2, (c) is the SEM image of MW, (d) is the SEM image of CuFe2O4, (e) is the SEM image of MWC-0.1 and (f) is the TEM image of MWC-0.1 prepared in Example 1.

[0035] Figure 2 The image shows the XPS analysis results of MWC-0.1 prepared in Example 1, where (a) is the full spectrum, (b) is the O1s spectrum, (c) is the Fe2p spectrum, (d) is the W4f spectrum, (e) is the Cu2p spectrum, and (f) is the S2p spectrum.

[0036] Figure 3 The graph shows the BET analysis results of CuFe2O4, MW, and MWC-0.1 prepared in Example 1, where a is the N2 adsorption-desorption curve and b is the pore size distribution.

[0037] Figure 4 Impedance spectra of CuFe2O4, MW, and MWC-0.1 prepared in Example 1.

[0038] Figure 5 The graph shows the effect of WS2, MW, and MWC-0.1 prepared in Example 1 on the degradation of pollutants in different systems.

[0039] Figure 6 The degradation curves of MWC-0.1 prepared in Example 1 at different initial pH values ​​are shown.

[0040] Figure 7 The image shows the cyclic stability of MWC-0.1 obtained in Example 1.

[0041] Figure 8 The image shows the XRD patterns of MWC-0.1 prepared in Example 1 before and after the degradation of phenol in a Fenton-like system.

[0042] Figure 9 The VSM plots of CuFe2O4 and MWC-0.1 prepared in Example 1 are shown, where a is the magnetometer curve of the vibrating sample and b is the magnetic recovery catalyst plot.

[0043] Figure 10 The EPR electron paramagnetic resonance images of WS2, MW, and MWC-0.1 obtained in Example 1 are shown. Detailed Implementation

[0044] The technical solutions of the present application will be described clearly and completely below in combination with the data in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0045] It should be noted that the professional terms used in the present application are only for the purpose of describing the specific embodiments and are not intended to limit the scope of protection of the present application. Unless otherwise specified, the various raw materials, reagents, instruments and equipment used in the following embodiments of the present application can be purchased from the market or prepared by the existing method.

[0046] In the prior art, heterogeneous Fenton-like technology, as a kind of advanced oxidation technology, has the advantages of high treatment efficiency and relatively low cost, but still faces many problems in practical application, such as narrow pH range, difficulty in recycling and reuse of catalyst, poor stability, low utilization rate of PMS (Persulfate) and low conversion efficiency between Fe 2+ activating SO4 2- The rate of generating sulfate radicals (SO4 ·- ) and the conversion efficiency between Fe 3+ and Fe 2+ are not ideal. Although CuFe2O4 has catalytic performance, it has the problems of weak electronic conductivity, limited pH adaptability and easy agglomeration when used, which limits its application in wastewater treatment.

[0047] In view of the problems existing in the prior art, the present application proposes a preparation method of a ternary composite heterogeneous Fenton-like catalyst, comprising the following steps: mixing MIL-88A / WS2, CuFe2O4, ethylene glycol and water and carrying out hydrothermal reaction, in the hydrothermal reaction process, CuFe2O4 is loaded on MIL-88A / WS2 and interacts with the sulfur atoms on the surface of WS2 and the metal sites in MIL-88A to form new chemical bonds, build a circulation channel with copper ions, iron ions and tungsten ions, and obtain a MIL-88A / WS2 / CuFe2O4 ternary composite heterogeneous Fenton-like catalyst, wherein the mass ratio of MIL-88A / WS2, CuFe2O4, ethylene glycol and water is 2:1-8:5:1.

[0048] The ternary composite heterogeneous Fenton-like catalyst prepared by the present application not only overcomes the defects of weak electronic conductivity, limited pH adaptability and easy agglomeration of CuFe2O4, but also solves the problems of poor stability of the catalyst, difficulty in recycling and reuse, low utilization rate of PMS and low degradation efficiency in the heterogeneous Fenton-like technology.

[0049] In order for those skilled in the art to more clearly understand the technical solutions of the present application, the technical solutions of the present application will be described below in detail with specific examples.

[0050] Example 1

[0051] A preparation method of a ternary composite heterogeneous Fenton-like catalyst, specifically comprising the following steps:

[0052] S1, preparation of MIL-88A(Fe):

[0053] Put 10 mmol of FeCl3·6H2O (2.703 g) and 10 mmol of C4H4O4 (1.1607 g) into a beaker containing 50 mL of deionized water and continuously stir for 15 min; then, place it in a Teflon-lined stainless steel high-pressure reaction kettle with a capacity of 150 mL; then, heat in a 100℃ blast drying oven for 12 h. After the reaction is completed, naturally cool to room temperature. Centrifuge the orange-brown product at a speed of 8000 r / min for 8 min, and finally, wash thoroughly with deionized water and anhydrous ethanol, and dry in a vacuum drying oven at 60℃ for 12 h to obtain MIL-88A(Fe).

[0054] S2, preparation of WS2:

[0055] Weigh one of WCl6 (0.9914 g, 2.5 mmol) and thioacetamide (2.2539 g, 30 mmol), and add it to a beaker containing 60 mL of anhydrous ethanol, and stir for 30 min to mix well. Then heat in a 100 ml Teflon-lined hydrothermal reactor at 200℃ for 24 h. After the reaction kettle is naturally cooled to room temperature, collect the black product produced in the reaction system, and wash it with deionized water and anhydrous ethanol alternately for 6 times. Finally, dry in a vacuum drying oven at 70℃ for 12 h to obtain WS2.

[0056] S3, preparation of CuFe2O4:

[0057] CuFe2O4 is prepared by co-precipitation method. First, 0.025 mol of Cu(NO3)2·3H2O (6.04 g) and 0.05 mol of Fe(NO3)3·9H2O (20.20 g) are added to a beaker containing 100 mL of deionized water, stirred for 30 min, and then transferred to a three-necked flask. Then, 75 mL of 4.0 mol NaOH solution is added dropwise while stirring, and heated at 90℃ for 2 h. After cooling to room temperature, wash, dry, and then heat to 600℃ at a rate of 2℃ / min in a test tube, and then keep the temperature for 2 h to obtain CuFe2O4.

[0058] S4, preparation of MIL-88A / WS2:

[0059] 0.2 g of WS2 was mixed with 0.1 g of MIL-88A(Fe) in a mixed solution of 25 mL of ethylene glycol and 5 mL of deionized water, after ultrasonic treatment for 30 min, placed in a 50 mL teflon lined hydrothermal reactor, heated at 120°C for 12 h, washed and dried to obtain MIL-88A / WS2, denoted as MW.

[0060] S5, Preparation of a ternary composite heterogeneous Fenton-like catalyst MIL-88A / WS2 / CuFe2O4:

[0061] On the basis of MIL-88A / WS2, CuFe2O4 was compounded, 0.2 g of MIL-88A / WS2 was mixed with 0.1 g of CuFe2O4 in a mixed solution of 25 mL of ethylene glycol and 5 mL of deionized water, after ultrasonic treatment for 30 min, placed in a 50 mL teflon lined hydrothermal reactor, heated at 120°C for 12 h, washed and dried to obtain MIL-88A / WS2 / CuFe2O4, a ternary composite heterogeneous Fenton-like catalyst, denoted as MWC-0.1.

[0062] Example 2

[0063] A preparation method of a ternary composite heterogeneous Fenton-like catalyst, which is the same as the preparation method of Example 1, except that the amount of CuFe2O4 in S5 is replaced by 0.2 g instead of 0.1 g, to obtain MIL-88A / WS2 / CuFe2O4, a ternary composite heterogeneous Fenton-like catalyst, denoted as MWC-0.2.

[0064] Example 3

[0065] A preparation method of a ternary composite heterogeneous Fenton-like catalyst, which is the same as the preparation method of Example 1, except that the amount of CuFe2O4 in S5 is replaced by 0.4 g instead of 0.1 g, to obtain MIL-88A / WS2 / CuFe2O4, a ternary composite heterogeneous Fenton-like catalyst, denoted as MWC-0.4.

[0066] Example 4

[0067] A preparation method of a ternary composite heterogeneous Fenton-like catalyst, which is the same as the preparation method of Example 1, except that the amount of CuFe2O4 in S5 is replaced by 0.6 g instead of 0.1 g, to obtain MIL-88A / WS2 / CuFe2O4, a ternary composite heterogeneous Fenton-like catalyst, denoted as MWC-0.6.

[0068] Example 5

[0069] A preparation method of a ternary composite heterogeneous Fenton-like catalyst, which is the same as the preparation method of Example 1, except that the amount of CuFe2O4 in S5 is replaced by 0.8 g instead of 0.1 g, to obtain MIL-88A / WS2 / CuFe2O4, namely a ternary composite heterogeneous Fenton-like catalyst, denoted as MWC-0.8.

[0070] Examples 1 to 5 of the present application all prepared ternary composite heterogeneous Fenton-like catalysts, and the morphologies are basically consistent. The ternary composite heterogeneous Fenton-like catalyst prepared in Example 1 was subjected to scanning electron microscopy test, and the following was observed Figure 1 It is concluded that Figure 1 the a graph in the above appears a spindle rod structure, indicating that MIL-88A is successfully prepared; Figure 1 the b graph in the above appears a nanosheet layer stacked spherical structure, and the nanosheet layer on the spherical surface is full, which indicates that WS2 is successfully prepared; Figure 1 the c graph in the above is that WS2 is loaded on MIL-88A in a nanoflower layer structure, and MIL-88A / WS2 is successfully prepared; Figure 1 the d graph in the above is a CuFe2O4 spherical structure, and CuFe2O4 is successfully prepared; Figure 1 the e graph in the above is that WS2 is loaded on MIL-88A in a nanoflower layer structure, and the nanosheet layer is further loaded with CuFe2O4 spherical structure, and the ternary composite material MIL-88A / WS2 / CuFe2O4 is successfully prepared. In summary, MIL-88A(Fe), WS2, CuFe2O4, MW and MWC-0.1 are successfully prepared in Example 1, and are uniformly distributed on the spindle-shaped material MIL-88A(Fe).

[0071] Figure 2 (a) in the above shows that C, O, S, Fe, W and Cu elements exist in the ternary composite heterogeneous Fenton-like catalyst, indicating that the ternary composite heterogeneous Fenton-like catalyst is successfully prepared; Figure 2 (b) in the above is an XPS spectrum of O1s, in which three obvious peaks belong to W-O, Fe-O and -COOH respectively, indicating that WS2 and MIL-88A(Fe) are preserved in MWC-0.1; Figure 2 (c) in the above shows an XPS spectrum of Fe 2p, and the peaks at 709.9 and 723.1 eV correspond to Fe 2+ 2p 3 / 2 and 2p 1 / 2 , the peaks at 713.3 and 726.8 eV correspond to Fe 3+ 2p 3 / 2 and 2p 1 / 2 , indicating that Fe 2+ / Fe 3+In addition, satellite peaks were found at 717.1 and 730.9 eV; Figure 2 (d) shows the XPS spectrum of W 4f, the peaks belonging to W 4+ 4f 5 / 2 and W 4f 7 / 2 orbital splitting, the characteristic peaks at 32.0 eV and 34.1 eV belong to 1T-WS2, and the characteristic peak at 33.1 eV belongs to 2H-WS2, which indicates that 1T-WS2 and 2H-WS2 coexist in MW-0.1, and 1T-WS2 is dominant; Figure 2 (e) is the XPS spectrum of Cu 2p, there are two main Cu 2p 3 / 2 peaks with binding energies of 932.1 eV and 952.1 eV, respectively, belonging to Cu + and Cu 2+ , respectively, and the corresponding peak positions of Cu 1 / 2 and Cu + can also be found in the Cu 2p 2+ peak. A strong Cu 2+ satellite peak can be observed at a binding energy of 943.4 eV; Figure 2 (f) is the S2p spectrum, in which the binding energies of S2p 3 / 2 (161.7 eV) and S2p 1 / 2 (163.0 eV) can be assigned to S 2- orbital, which indicates that there are sulfur species (referring to sulfides and sulfates) and Fe-S bonds on the surface of MWC-0.1. The peaks at 164.3 and 169.2 eV are unsaturated sulfur and sulfate (SOX), respectively. Based on the above results, there are various active sites of Fe 3+ / Fe 2+ , Cu 2+ / Cu + , W 6+ / W 4+ and unsaturated S in MWC-0.1. It is proved that 1T phase WS2 and the ternary composite heterogeneous Fenton-like catalyst are successfully prepared.

[0072] The MIL-88A / WS2 / CuFe2O4 ternary composite heterogeneous Fenton-like catalyst prepared in Example 1 of the application is taken as an example, which is applied to activate PMS to degrade phenol, and the degradation effect is explored. The specific application method is as follows:

[0073] The MWC-0.1 prepared in Example 1 was used to carry out a heterogeneous Fenton-like reaction, and the specific steps were as follows: the MW-0.1 was added to a glass beaker containing 200 mL of a 20 mg / L phenol solution, and after 30 min of reaction in the dark to reach adsorption equilibrium, the monopersulfate was added to the above solution, and the mass ratio of MWC-0.1 to monopersulfate was 0.06:0.1228, to initiate the heterogeneous Fenton-like reaction. When the reaction was carried out for 60 min, 4 mL of the suspension was extracted, and 0.2 mL of methanol was added as a quenching agent to terminate the reaction; then, after filtration with a 0.22 μm filter membrane, 2 mL of the supernatant was extracted for determination.

[0074] The determination method was as follows: the tetraaminoantipyrine spectrophotometry was used to determine the phenol, and a 722G visible spectrophotometer was used for determination, and the wavelength was 510 nm.

[0075] Observation Figure 3 It was concluded that the specific surface area of the ternary composite heterogeneous Fenton-like catalyst was improved, and it was a typical mesoporous material. Figure 3 The isotherm shape of MW and MWC-0.1 in the a graph in FIG. 1 was consistent with the isotherm shape of type IV, and the type IV isotherm of the H3 hysteresis loop was in a relatively high relative pressure range (P / P0=0.45-1.0), which indicated that MW and MWC-0.1 were mesoporous structures. At the same time, it was proved that the ternary composite heterogeneous Fenton-like catalyst prepared in the application had the characteristics of type IV isotherm, and there was a hysteresis loop. The specific surface areas of MWC-0.1, MW and CuFe2O4 were 24.1492 m 2 / g, 15.3878 m 2 / g and 17.0788 m 2 / g, respectively. Figure 3 The pore diameter of the ternary composite material was the largest in the b graph in FIG. 1. These results proved that, due to the presence of CuFe2O4, the ternary composite heterogeneous Fenton-like catalyst MWC-0.1 could provide a larger contact area and channel for the interaction between the reaction active site and the target pollutants compared with MW, thereby having higher catalytic activity.

[0076] The MW, CuFe2O4 and MWC-0.1 prepared in Example 1 were respectively used as working electrodes, an Ag / AgCl electrode was used as a reference electrode, and a platinum sheet electrode was used as a counter electrode, one end of the working electrode, the reference electrode and the counter electrode was placed in a 0.5 mol / L Na2SO4 solution, and the other end was electrically connected with an electrochemical workstation (CHI660E), and electrochemical analysis was carried out at a scanning rate of 5 mV / s, and the detection results were as follows:

[0077] From the results of the electrochemical analysis, it could be seen that the ternary composite heterogeneous Fenton-like catalyst MWC-0.1 had the highest catalytic activity. Figure 4It is concluded that the MWC-0.1 has the smallest arc radius among all ternary composite heterogeneous Fenton-like catalysts. The EIS results show that, compared with the use of MW and CuFe2O4 alone, the formation of heterojunction in MWC-0.1 provides the separation and slower recombination of carriers, thereby improving the catalytic performance.

[0078] WS2, MIL-88A, MW, CuFe2O4 and MWC-0.1 are mixed with peroxymonosulfate respectively, and the obtained systems are denoted as WS2 / PMS, MIL-88A / PMS, MW / PMS, CuFe2O4 / PMS and MWC-0.1 / PMS respectively; wherein the mass ratio of WS2, MIL-88A, MW, CuFe2O4 and MWC-0.1 to peroxymonosulfate is 0.06:0.1228.

[0079] a. 0.3 g / L of PMS, MW / PMS, CuFe2O4 / PMS, MIL-88A / PMS, MWC-0.1 / PMS, WS2 / PMS or MWC-0.1 respectively is mixed with a phenol solution with an initial mass concentration of 20 mg / L and a pH of 7.0 at room temperature to carry out a degradation experiment, and the mass concentration of the phenol solution in the system is measured 。 The volume of the phenol is the total volume of the system, which is always 200 mL.

[0080] b. The prepared MWC-0.1 is subjected to a cycle experiment of phenol degradation, and the cycle method is: washing alternately with deionized water and anhydrous ethanol for three times, then drying in a vacuum drying oven, and then using.

[0081] Observation Figure 5 It is concluded that, in addition to MWC-0.1 / PMS and MW / PMS having strong degradation effect on phenol, the rest of the systems can only degrade a small part of phenol through a small part of PMS self-decomposition, and the degradation efficiency of the MWC-0.1 / PMS system is greatly improved compared with the MW / PMS system.

[0082] Observation Figure 6 It is concluded that the ternary composite heterogeneous Fenton-like catalyst of the present application can maintain high catalytic activity within the initial pH range of 3.0-9.0.

[0083] From Figure 7 It is concluded that the ternary composite heterogeneous Fenton-like catalyst of the present application can still maintain good stability after 5 cycle experiments.

[0084] Observation Figure 8It was found that the position and intensity of the characteristic peak of MW C-0.1 remained almost unchanged before and after the degradation of phenol in the MWC-0.1 / PMS Fenton-like system. This indicates that the basic structure of MWC-0.1 remained intact and stable during the reaction, demonstrating that the ternary composite heterogeneous Fenton-like catalyst of the present invention has excellent stability.

[0085] observe Figure 9 Figure a shows that the saturation magnetization of the ternary composite heterogeneous Fenton catalyst is 26.87 emu / g, indicating that it has very good magnetic properties. Figure 9 Figure b in the figure shows that the ternary composite heterogeneous Fenton-like catalyst has good magnetic recovery ability.

[0086] observe Figure 10 It was found that as the number of hydrothermal cycles increased, the S-vacancy signal gradually strengthened, and the strongest S-vacancy peak appeared at MWC-0.1, indicating that S-vacancy was generated in the ternary composite heterogeneous Fenton-like catalyst.

[0087] It should be noted that when numerical ranges are involved in this invention, it should be understood that both endpoints of each numerical range, as well as any value between the two endpoints, can be selected. Since the steps and methods used are the same as in the embodiments, preferred embodiments are described here to avoid redundancy. Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this invention.

Claims

1. A method for preparing a ternary composite heterogeneous Fenton-like catalyst, characterized in that, Comprising the following steps: MIL-88A / WS2, CuFe2O4, ethylene glycol and water are mixed and subjected to hydrothermal reaction, in the process of hydrothermal reaction, CuFe2O4 is loaded on MIL-88A / WS2 and interacts with the sulfur atoms on the surface of WS2 and the metal sites in MIL-88A to form new chemical bonds, thereby obtaining a MIL-88A / WS2 / CuFe2O4 ternary composite heterogeneous Fenton-like catalyst; The mass ratio of MIL-88A / WS2, CuFe2O4, ethylene glycol and water is 2:1-8:5:

1. The hydrothermal reaction is carried out at 110-120°C for 11-12h.

2. The preparation method of the ternary composite heterogeneous Fenton-like catalyst according to claim 1, characterized in that, CuFe2O4 is prepared by the following steps: NaOH solution is added dropwise to a mixed solution of Cu(NO3)2·3H2O, Fe(NO3)3·9H2O and water, and a co-precipitation reaction is carried out at 85-90°C for 1.5-2h, followed by calcination to obtain CuFe2O4. The molar ratio of Cu(NO3)2·3H2O, Fe(NO3)3·9H2O and NaOH is 2.5-3:5-6:300-400.

3. The method for preparing the ternary composite heterogeneous Fenton-like catalyst according to claim 1, characterized in that, MIL-88A / WS2 is prepared by the following steps: WS2, MIL-88A(Fe), ethylene glycol and water are mixed and subjected to hydrothermal reaction to obtain MIL-88A / WS2. The mass ratio of WS2 and MIL-88A(Fe) is 2:

1.

4. The preparation method of the ternary composite heterogeneous Fenton-like catalyst according to claim 3, characterized in that, The hydrothermal reaction is carried out at 110-120°C for 11-12h.

5. A ternary composite heterogeneous Fenton-like catalyst prepared by the preparation method of any one of claims 1-4.

6. The ternary composite heterogeneous Fenton-like catalyst according to claim 5, characterized in that, In the ternary composite heterogeneous Fenton-like catalyst, WS2 is coated on the spindle rod-shaped MIL-88A in a nanosheet layer structure, and spherical CuFe2O4 is loaded on the nanosheet layer.

7. The use of the ternary composite heterogeneous Fenton-like catalyst of claim 5 in the preparation of a phenolic wastewater treatment agent.

8. Use of the ternary composite heterogeneous Fenton-like catalyst according to claim 7 for the preparation of a phenolic wastewater treatment agent, characterized in that, The application method is: The ternary composite heterogeneous Fenton-like catalyst is mixed with a phenol solution, and peroxymonosulfate is added under light shielding conditions, followed by stirring reaction, and a quenching agent is added to terminate the reaction. The mass / volume ratio of the ternary composite heterogeneous Fenton-like catalyst, peroxymonosulfate and phenol solution is 0.06-0.1g:0.1228g:200mL.

9. Use of the ternary composite heterogeneous Fenton-like catalyst according to claim 8 for the preparation of a phenolic wastewater treatment agent, characterized in that, The mass concentration of the phenol solution is 20-25mg / L.

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