MgO / ZrO2 supported solid base catalyst as well as preparation method and application thereof

Abstract

The invention discloses an MgO / ZrO2 supported solid base catalyst as well as a preparation method and application thereof, and relates to the technical field of catalysts. According to the MgO / ZrO2 supported solid base catalyst disclosed by the invention, MgO is supported on a tetragonal phase ZrO2 carrier, Mg < 2 + > ions are relatively small in radius and relatively large in electronegativity, so that after the Mg < 2 + > ions are introduced into the carrier ZrO2, the Mg < 2 + > ions can be tightly combined with ZrO2 under the action of coulomb gravitation to form a chelate, and the chelate has excellent electron donating ability, so that the solid base catalyst can be used for preparing a solid base catalyst. The catalyst prepared by the method can serve as a strong Lewis base site, so that the catalyst has an excellent catalytic effect on degradation of cured epoxy resin, the reactant conversion rate of 71% or above can be obtained at the low temperature of not higher than 250 DEG C, directional depolymerization of the epoxy resin can be realized, and the selectivity of gas products in products reaches 63.66% or above.

Description

Technical Field

[0001] This invention relates to the field of catalyst technology, specifically to a MgO / ZrO2 supported solid base catalyst, its preparation method, and its application. Background Technology

[0002] Composite insulators have been widely used in power transmission lines due to their excellent anti-pollution flashover capabilities. However, the design life of these insulators is typically 15 to 20 years. Currently, insulators that have been in use for more than 10 years account for more than 50% of the total number used in my country, posing both safety hazards and the challenge of concentrated retirement.

[0003] Composite insulators mainly consist of three parts: a silicone rubber shed, an epoxy fiberglass core rod, and end fittings. The epoxy fiberglass core rod, providing mechanical load-bearing and electrical insulation, is the primary component responsible for insulation. It comprises a cured epoxy resin layer and a fiberglass core rod (epoxy resin and fiberglass account for approximately 20% and 80% of the core rod's total weight, respectively). The cured epoxy resin layer is primarily composed of epoxy resin, a curing agent, and a curing accelerator. The epoxy resin used in composite insulator core rods is generally bisphenol A type epoxy resin, and the curing agent is typically an anhydride-based curing agent.

[0004] The recycling process of epoxy fiberglass core rods in decommissioned composite insulators requires the complete separation and recycling of thermosetting epoxy resin and fiberglass core rods. Therefore, the recycling of epoxy fiberglass core rods mainly targets the epoxy resin portion. For cured epoxy resin, the current mainstream recycling technology is pyrolysis, specifically including gas pyrolysis, fluidized bed pyrolysis, microwave-assisted pyrolysis, and catalytic pyrolysis. However, these methods all rely on high temperatures (>400℃) to destroy the cross-linked network structure of epoxy resin, causing the breakage of chemical bonds such as CO, CN, and CC. Although pyrolysis can effectively decompose thermosetting epoxy resin composites, its random fracture characteristics result in complex product composition and difficulty in separation and purification, limiting the reuse value of the recycled materials and reducing economic efficiency. In contrast, catalytic pyrolysis technology can achieve the directional decomposition of epoxy resin at low temperatures, improving the selectivity of usable gaseous products and reducing the selectivity of unusable solids such as residual carbon, thus increasing the economic value of the products. Furthermore, if the catalyst is designed properly, pyrolysis can even be completed at room temperature, significantly improving product purity and recycling efficiency. Therefore, there is a need for a catalyst that can directionally catalyze the degradation of cured epoxy resin at low temperatures. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a MgO / ZrO2 supported solid base catalyst, its preparation method, and its application.

[0006] The above-mentioned objective of this invention is achieved through the following technical solution: A MgO / ZrO2 supported solid base catalyst includes a support and an active component, wherein the support comprises tetragonal ZrO2 and the active component comprises MgO; the loading of the active component on the catalyst is 20-30 wt%.

[0007] The solid base catalyst provided by this invention possesses a unique electron-donating catalytic reaction mechanism, thus enabling low-temperature, targeted degradation of cross-linked and cured epoxy resins. Specifically, in the catalyst provided by this invention, MgO is an ionic compound capable of donating Mg... 2+ And due to Mg 2+ With a small ionic radius and high electronegativity, Mg is introduced into the support ZrO2 (which inevitably contains hydroxyl groups on its surface). 2+ After ionization, Mg under the influence of Coulomb attraction 2+ Ions tightly bind with hydroxyl groups on the ZrO2 surface and with O elements in the crystal lattice that can provide a certain number of lone electrons, forming chelates. These chelates have excellent electron-donating ability, can act as strong Lewis base sites, and exhibit good catalytic activation performance. It should be noted that excessive loading of the active component in this invention can easily lead to agglomeration and reduce catalytic activity. Therefore, this application limits the loading of the active component on the catalyst to 20-30 wt%. It should also be noted that zirconium dioxide in this application must be in the tetragonal phase. Other crystal phases, such as the cubic phase, have reduced interaction with MgO. Specifically, due to its metastable characteristics and high surface energy, the surface atoms of tetragonal ZrO2 are in a highly coordinated unsaturated state. To reduce energy and stabilize itself, it strongly adsorbs and dissociates water molecules during the preparation and storage of tetragonal ZrO2, thereby forming the most numerous and diverse hydroxyl groups on its surface. ZrO2 mainly relies on the surface hydroxyl groups to react with MgO. 2+ Ions undergo ion exchange or complexation reactions to form chelates with a robust -Zr-O-Mg- chemical structure. Therefore, the interaction between the tetragonal phase, which has the highest surface hydroxyl content, and MgO is optimal.

[0008] Preferably, the average particle size of the MgO / ZrO2 supported solid base catalyst is 80-500 nm.

[0009] If the catalyst particle size is too large, the specific surface area will be too low, resulting in decreased catalytic activity; conversely, if the catalyst particle size is too small, the catalyst structure may be unstable, and the particle size may also lead to agglomeration and destruction of the base site center. Taking all factors into consideration, the present invention preferably uses an average particle size of 80-500 nm for the MgO / ZrO2 supported solid base catalyst.

[0010] In a specific embodiment of the present invention, the average particle size of the MgO / ZrO2 supported solid base catalyst is measured as follows: A scanning electron microscope is used at an accelerating voltage of 15 keV, and 15 particles are randomly selected for particle size measurement; the magnification is 2500x. The average particle size is calculated based on the particle sizes of the selected 15 particles.

[0011] This invention also protects the preparation method of the above-mentioned MgO / ZrO2 supported solid base catalyst, comprising the following steps: The Mg source and Zr source are mixed in solution, the pH is adjusted to 8-9 to precipitate, then aged, solid-liquid separated to obtain the solid, dried, and then calcined at 600-900℃ for 2-6 h to obtain the final product.

[0012] The catalyst in this invention was prepared by impregnation-calcination. Mg 2+ [Mg(H2O) in the precursor solution] n ] 2+ Ions can undergo ion exchange or complexation reactions with hydroxyl groups on the ZrO2 surface to form strong -Zr-O-Mg- chemical bonds, which not only improves catalytic activity but also enhances the stability and dispersibility of Mg loaded on the ZrO2 surface. Furthermore, the Mg introduced during the impregnation process... 2+ (Ionic radius ~0.072 nm) can partially enter the ZrO2 lattice (Zr 4+ With an ionic radius of ~0.084 nm, it plays a role in stabilizing the highly active tetragonal phase of ZrO2.

[0013] Preferably, the precipitation is carried out under stirring conditions, the stirring time is 2-6 h, and the stirring speed is 2000-3000 rpm.

[0014] Preferably, the solution conditions are provided using water.

[0015] Preferably, the Mg source includes MgCl2·6H2O.

[0016] Preferably, the Zr source includes ZrOCl2.

[0017] Preferably, the mass ratio of water, Mg source and Zr source is 500:(8-10):(15-20).

[0018] Preferably, the mixing is carried out under stirring conditions, and the stirring speed is 2000-3000 rpm. More preferably, the mixing is carried out at room temperature for 5-20 minutes.

[0019] Preferably, the pH is adjusted to 8-9 using ammonia solution with a concentration of 5-30 wt%.

[0020] More preferably, the pH adjustment is performed under stirring conditions, with the stirring speed being 7000-8000 rpm. More preferably, the pH is adjusted to 8-9 by adding ammonia water dropwise.

[0021] Adjusting the pH with ammonia helps stabilize the catalyst structure. Strongly alkaline reagents may damage the catalyst structure and affect catalyst synthesis.

[0022] Preferably, after adjusting the pH to 8-9 for precipitation and before aging, the process further includes a stirring and dispersion step, wherein the stirring and dispersion speed is 2000-3000 rpm. More preferably, the stirring and dispersion time is 2-6 hours.

[0023] Preferably, the aging process is carried out at 20-30°C for 20-30 hours.

[0024] Preferably, the solid-liquid separation process further includes a washing step, wherein the washing is water washing followed by methanol washing, repeated three times. Preferably, the drying temperature is 120°C and the drying time is 10-14 hours.

[0025] Preferably, the calcination is carried out in an air atmosphere.

[0026] Preferably, the temperature is raised to 600-900℃ at a heating rate of 1-10℃ / min.

[0027] This invention also protects the application of the MgO / ZrO2 supported solid base catalyst in the degradation and curing of epoxy resins.

[0028] This invention also protects a method for catalytically degrading and curing epoxy resin, comprising the following steps: The cured epoxy resin is dissolved in an organic solvent, and the epoxy resin solution is obtained by solid-liquid separation. Then, the MgO / ZrO2 supported solid base catalyst is pyrolyzed at 100-250℃ for 4-8 h.

[0029] Preferably, the organic solvent includes at least one of dimethylformamide and methanol.

[0030] More preferably, the organic solvent comprises dimethylformamide and methanol in a volume ratio of (0.5-2):1.

[0031] To fully degrade cured epoxy resin, it needs to be dissolved first; conversely, to effectively dissolve epoxy resin, it needs to be swollen first. According to the principle of "like dissolves like," epoxy resin swells well but does not completely dissolve in poor solvents (such as methanol); however, it has good solubility in good solvents (such as dimethylformamide) and can usually dissolve completely to form a homogeneous solution. Therefore, adjusting the ratio of these two solvents has a significant impact on obtaining a good epoxy resin solution and completing the catalytic cracking process.

[0032] Preferably, the mass ratio of the catalyst to the epoxy resin solution is 1:(8-12).

[0033] Preferably, the cured epoxy resin comprises anhydride-cured bisphenol A type epoxy resin.

[0034] Compared with the prior art, the present invention has the following beneficial effects: The catalyst provided by this invention has excellent catalytic degradation effect on cured epoxy resin (bisphenol A type epoxy resin cured by acid anhydride) in epoxy glass core rod. It can achieve a reactant conversion rate of up to 71% or more at a low temperature of no more than 250°C, and can realize the directional depolymerization of epoxy resin. The gas product selectivity in the product is as high as 63.66% or more. Attached Figure Description

[0035] Figure 1 The image shows the XRD pattern of the catalyst obtained in Example 1.

[0036] Figure 2 This is a SEM image of the catalyst obtained in Example 1.

[0037] Figure 3 The images show the FT-IR spectra of the catalysts obtained in Example 1 and Comparative Example 3.

[0038] Figure 4 The image shows the SEM image of the catalyst obtained in Comparative Example 3.

[0039] Figure 5 Optical photographs of the pyrolysis products of an epoxy resin mandrel before (a) and after (b) catalytic pyrolysis using the catalyst obtained in Example 1.

[0040] Figure 6 The graph shows the thermogravimetric analysis (TG) of the epoxy resin mandrel under the catalytic cracking of the catalyst obtained in Example 1. Detailed Implementation

[0041] The present invention will be further described below with reference to specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise stated, the raw materials and reagents used in the embodiments of the present invention are conventionally purchased raw materials and reagents. The raw material information used in the embodiments and comparative examples is as follows: Cured epoxy resin: Obtained by disassembling epoxy fiberglass core rods from decommissioned composite insulators conforming to GB 19519-2014. Its main component is bisphenol A type epoxy resin cured with anhydride, wherein the molar ratio of the anhydride groups in the anhydride curing agent to the epoxy groups in the epoxy resin is (0.85-0.95):1. The disassembly method is as follows: the epoxy fiberglass core rods are dispersed in dimethylformamide for dissolution, and the undissolved glass fibers and fillers are filtered out to obtain an epoxy resin solution; after drying, the cured epoxy resin is obtained.

[0042] Example 1 and Comparative Examples 1-2 This embodiment and the comparative example provide a series of MgO / ZrO2 supported solid base catalysts with different loadings of active components, wherein the average particle size of each catalyst is ~100 nm.

[0043] The catalyst preparation method provided in this embodiment and the comparative example includes the following steps: ZrOCl2, MgCl2·6H2O and deionized water were added to a beaker in proportion (the mass ratio of water, Mg source and Zr source in Example 1 was 500:9.5:17.8). The mixture was stirred with a magnetic stirrer (7536 rpm) for 10 min at room temperature until a homogeneous solution was obtained. 10 wt.% NH3 aqueous solution was added dropwise to the above mixed solution while stirring with a magnetic stirrer (7536 rpm) until the pH value of the solution reached 8-9. The solution was stirred thoroughly at 2512 rpm for 4 h and aged for 24 h. The solution was filtered by centrifuge and the precipitate was collected. The precipitate was washed three times with deionized water and methanol. The obtained solid was dried at 120°C for 12 h. The dried sample was heated to 700°C at a heating rate of 5°C / min in air and calcined for 4 hours to obtain MgO / ZrO2 powder.

[0044] The loading amounts of active components in the catalysts obtained in Example 1 and Comparative Examples 1-2 are shown in Table 1 below: Table 1. The catalyst obtained in Example 1 was characterized, and the test results are as follows: Figure 1-3 As shown: according to Figure 1 The ZrO2 crystalline phase of the catalyst obtained in Example 1 of this invention is mainly tetragonal, exhibiting good crystallinity. According to... Figure 2 The catalyst obtained in Example 1 of this invention has an average particle size of ~100 nm, which is relatively small. This may be related to the presence of Mg. 2+The small ionic radius is related to this. The nanocrystal surface has a certain smoothness, which may be related to the pH value of the solution. Introducing MgO during the synthesis process will result in a higher pH value, at which point excess OH-... - Ions may preferentially adsorb on the higher-energy {111} crystal planes of MgO, effectively "passivating" these planes, reducing their growth rate, and thus resulting in a smooth surface. According to... Figure 3 The content of Lewis base sites in the catalyst obtained in Example 1 was tested by pyridine adsorption. Figure 3 It can be known that 1225 cm −1 1041 cm −1 The diffraction peaks at these locations correspond to Lewis base sites. This is mainly because the special structure of MgO / ZrO2 nanocrystals has a large number of electron-donating centers, which act as strong Lewis base sites.

[0045] Example 2 A MgO / ZrO2 supported solid base catalyst with an average particle size of ~500 nm.

[0046] The only difference between the catalyst preparation method in this embodiment and that in Example 1 is: The dried sample was calcined at 700℃ for 6 hours.

[0047] Example 3 A MgO / ZrO2 supported solid base catalyst with an average particle size of ~750 nm.

[0048] The only difference between the catalyst preparation method in this embodiment and that in Example 1 is: The dried sample was calcined at 700℃ for 8 hours.

[0049] Example 4 A MgO / ZrO2 supported solid base catalyst with an average particle size of ~50 nm.

[0050] The only difference between the catalyst preparation method in this embodiment and that in Example 1 is: The dried sample was calcined at 700℃ for 2 hours.

[0051] Example 5 A MgO / ZrO2 supported solid base catalyst, the preparation method of which differs from that of Example 1 only in that: After mixing the Mg source and Zr source, ammonia water was added to adjust the pH to 10 for precipitation. After stirring, the mixture was aged for 36 h.

[0052] Example 6 A MgO / ZrO2 supported solid base catalyst, the preparation method of which differs from that of Example 1 only in that: After mixing the Mg source and Zr source, ammonia water was added to adjust the pH to 7 for precipitation. After stirring, the mixture was aged for 12 hours.

[0053] Comparative Example 3 A solid MgO base catalyst with an average particle size of ~200 nm. Its main difference from Example 1 is that no ZrO2 support was introduced.

[0054] The only difference between the catalyst preparation method in this comparative example and that in Example 1 is: Do not add ZrOCl2.

[0055] The catalyst obtained in this comparative example was characterized, and the test results are as follows: Figure 4 As shown: according to Figure 4 It can be observed that the size of the prepared MgO sample is between 100-400 nm, and it has a distinct nanocrystalline structure.

[0056] Comparative Example 4 The main difference between this MgO / TiO2 supported solid base catalyst and Example 1 is that: The carrier was replaced by TiO2 instead of ZrO2.

[0057] The only difference between the catalyst preparation method in this comparative example and that in Example 1 is: Replace ZrOCl2 with an equimolar amount of TiOCl2.

[0058] Comparative Example 5 The main difference between this SiO2 / ZrO2 supported solid base catalyst and Example 1 is that: The active component was replaced by CaO instead of MgO.

[0059] The only difference between the catalyst preparation method in this comparative example and that in Example 1 is: Replace MgCl2·6H2O with an equimolar amount of CaCl2.

[0060] Comparative Example 6 The main difference between this SiO2 / ZrO2 supported solid base catalyst and Example 1 is that: The active component was replaced by BaO instead of MgO.

[0061] The only difference between the catalyst preparation method in this comparative example and that in Example 1 is: Replace MgCl2·6H2O with an equimolar amount of BaCl2.

[0062] Comparative Example 7 The main difference between this MgO / ZrO2 supported solid base catalyst and Example 1 is that: The support was replaced by cubic ZrO2 instead of tetragonal ZrO2.

[0063] The only difference between the catalyst preparation method in this comparative example and that in Example 1 is: The calcination temperature is 1000℃.

[0064] Performance testing I. Basic Catalytic Activity Test Cut the cured epoxy resin into 1×1×1 cm pieces. 3 The epoxy resin block was prepared by weighing 50 mL of dimethylformamide and 50 mL of methanol into a 150 mL beaker and stirring at 7536 rpm for 5 min until a homogeneous solution was obtained. Then, the cut epoxy fiberglass core rod block was added, and the mixture was stirred at room temperature for 12 h until the epoxy resin block was completely dissolved. The mixture was filtered, and the filtrate was retained. 10 g of the catalyst obtained in the examples and comparative examples was added to the filtrate, and the mixture was stirred at 2512 rpm for 20 min. The mixture was then distilled at 180°C for 5 h to obtain the depolymerization product. Gas chromatography (GC) was performed on the product to obtain the conversion rate of the epoxy resin reactant and the selectivity of the gaseous products (CO, CO2). The GC detection conditions were as follows: Inlet air temperature: 80 ℃; Column temperature: 35 ℃, retention time: 3 min; Carrier gas: High-purity He (He≥99.999%); Injection volume: 0.1 mL Temperature programming: 50-270 ℃; Heating rate: 5°C / min; Injector and detector temperature: 270°C.

[0065] Reactant conversion and product selectivity are calculated using the following formula: [COx yield] = [COx]out / ([epoxy resin]in - [epoxy resin]out) × 100%.

[0066] [Epoxy resin conversion rate] = ([epoxy resin]in - [epoxy resin]out) / [epoxy resin]in × 100%.

[0067] The test data is shown in Table 2 below: Table 2. As can be seen from Table 2 above, the catalyst provided by the present invention has excellent catalytic effect on epoxy resin (mainly bisphenol A type epoxy resin cured by acid anhydride) in epoxy glass core rod. It can achieve a reactant conversion rate of up to 71% or more at a low temperature of no more than 250°C, and can realize the directional depolymerization of epoxy resin. The gas product selectivity in the product is as high as 63.66% or more.

[0068] As can be seen from the data in Examples 1-4, the average particle size of the solid alkali catalyst can be controlled by changing the calcination time. When the average particle size of the catalyst is 80-300 nm (Examples 1-2), the resulting catalyst has higher selectivity for gaseous products when catalytically degrading cured epoxy resin, and the products have higher reuse value.

[0069] According to Examples 1 and 5-6, the pH and time during the precipitation and aging processes also affect the catalytic degradation effect of the catalyst. This is mainly because the added precipitant is alkaline, which can affect the pH of the reaction system, and the pH value affects the growth rate of crystal nuclei. When the pH of the solution is too high, OH... - Ions may preferentially adsorb on the higher-energy {111} crystal faces of MgO, effectively "passivating" these faces and reducing their growth rate, thus improving the surface smoothness of the catalyst. A smooth surface structure has a smaller specific surface area, resulting in less contact area between the epoxy resin molecules and the catalyst, affecting catalytic performance. However, a rough surface structure is also detrimental to the contact between epoxy resin molecules and the catalyst, similarly impacting catalytic performance.

[0070] According to Comparative Examples 1-2, if the loading of the active component in the catalyst is too low, good catalysis cannot be achieved; however, if the loading is too high, the active component will easily agglomerate, which will also affect the catalytic effect.

[0071] According to Comparative Examples 3-7, without the addition of a support, the degradation of epoxy resin using magnesium oxide alone as a catalyst could not achieve good catalysis, even though magnesium oxide was the main active component. This indicates that there is a catalytically beneficial interaction between the support and magnesium oxide. Replacing the support or active component with other similar basic oxides, or changing the crystal form of zirconium oxide, could not achieve the excellent catalytic effect of this application, indicating that the interaction between tetragonal zirconium oxide and magnesium oxide is specific.

[0072] II. Solvent Optimization for Curing Epoxy Resins The solvents used to dissolve and cure epoxy resins were optimized, and the results are shown in Examples 1-4.

[0073] Example of an effect 1. A method for catalytic degradation of cured epoxy resin includes the following steps: Cut the epoxy resin into 1×1×1 cm pieces. 3The epoxy resin block was prepared by weighing 50 mL of dimethylformamide and 50 mL of methanol into a 150 mL beaker and stirring at 7536 rpm for 5 min until a homogeneous solution was obtained. Then, the cut epoxy fiberglass core rod block was added, and the mixture was stirred at room temperature for 12 h until the epoxy resin block was completely dissolved. The mixture was filtered, and the filtrate was retained. 10 g of the catalyst obtained in Example 1 was added to the filtrate, and the mixture was stirred at 2512 rpm for 20 min. The mixture was then distilled at 180 °C for 5 h to obtain the depolymerization product. Gas chromatography was used to determine the conversion rate of the epoxy resin reactant and the selectivity of the gaseous products.

[0074] Example of effect 2. A method for catalytic degradation of cured epoxy resin differs from Example 1 only in that: Weigh 67 mL of dimethylformamide and 33 mL of methanol.

[0075] Example of an effect 3. A method for catalytic degradation of cured epoxy resin differs from Example 1 only in that: Weigh 33 mL of dimethylformamide and 67 mL of methanol.

[0076] Example of an effect 4. A method for catalytic degradation of cured epoxy resin differs from Example 1 only in that: Weigh 25 mL of dimethylformamide and 75 mL of methanol.

[0077] The catalytic effects of the above-mentioned examples were tested, and the results are shown in Table 3: Table 3. As can be seen from the data of the above effect examples, the preferred embodiment of the present invention obtained by compounding dimethylformamide and methanol in a volume ratio of (0.5-2):1 has a better epoxy resin dissolution effect, which is beneficial to improving the catalytic effect.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A MgO / ZrO2 supported solid base catalyst, characterized by, The catalyst comprises a carrier and an active component, the carrier comprises tetragonal ZrO2, and the active component comprises MgO; the loading amount of the active component on the catalyst is 20-30 wt%.

2. The MgO / ZrO2 supported solid base catalyst according to claim 1, wherein the MgO / ZrO2 supported solid base catalyst is characterized by, The average particle size of the MgO / ZrO2 supported solid base catalyst is 80-500 nm.

3. A method for preparing the MgO / ZrO2 supported solid base catalyst according to any one of claims 1-2, characterized in that, The method comprises the following steps: The Mg source and the Zr source are mixed under solution conditions, and then precipitated by adjusting the pH to 8-9, followed by aging, solid-liquid separation to obtain the solid, drying, and calcination at 600-900 ℃ for 2-6 h.

4. The preparation method according to claim 3, characterized in that, The solution conditions are provided by water; The Mg source comprises MgCl2·6H2O; The Zr source comprises ZrOCl2.

5. The preparation method according to claim 3, characterized in that, The ammonia water with a concentration of 5-30 wt% is used to adjust the pH to 8-9; After the step of adjusting the pH to 8-9 for precipitation, the method further comprises a step of stirring and dispersing before the aging, and the stirring and dispersing are performed at a rotating speed of 2000-3000 rpm; The aging is performed at 20-30 ℃ for 20-30 h.

6. The preparation method according to claim 3, characterized in that, The calcination is performed in an air atmosphere; The temperature is increased to 600-900 ℃ at a temperature increasing rate of 1-10 ℃ / min.

7. The use of the MgO / ZrO2 supported solid base catalyst according to any one of claims 1-2 in the degradation of cured epoxy resin.

8. A method of catalytically degrading a cured epoxy resin, characterized by, The method comprises the following steps: The cured epoxy resin is dissolved by using an organic solvent, and then the epoxy resin solution is obtained by solid-liquid separation, followed by the addition of the MgO / ZrO2 supported solid base catalyst according to any one of claims 1-2, and the cracking is performed at 100-250 ℃ for 4-8 h.

9. The method of catalytic degradation of an epoxy resin according to claim 8, wherein, The organic solvent comprises at least one of dimethylformamide and methanol; The mass ratio of the catalyst to the epoxy resin solution is 1:(8-12); The cured epoxy resin comprises anhydride-cured bisphenol A type epoxy resin.

10. The method of catalytic degradation of an epoxy resin according to claim 9, wherein, The organic solvent comprises dimethylformamide and methanol at a volume ratio of (0.5-2):1.

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