Preparation method of supported catalyst

Abstract

The invention provides a preparation method of a supported catalyst, and belongs to the technical field of catalysts. The method provided by the invention comprises the following steps: uniformly dispersing a metal oxide precursor in a polymer solution to obtain a mixture; and molding the mixture, drying, and calcining to obtain the supported catalyst, the metal oxide precursor is an iron oxide precursor and a copper oxide precursor. The method provided by the invention realizes high dispersion of the metal oxide on the surface of the carrier. The highly uniform metal distribution mode not only improves the density of catalytic active sites, but also significantly enhances the stability of metal components in the use process, and effectively prevents the problems of metal agglomeration and loss, thereby ensuring the long-acting operation of the catalyst in various industrial scenes.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of catalysts, in particular to a preparation method of a supported catalyst. BACKGROUND

[0002] In the design of catalytic materials, supported catalysts are widely used due to their simple preparation steps. However, existing supported metal catalysts still have many deficiencies in terms of dispersion of metal components, uniformity of loading, and structural stability. If the metal components cannot be highly uniformly dispersed on the support, they are prone to agglomeration, aggregation, and even loss, which leads to a decrease in activity and selectivity, and seriously affects the long-term performance of the catalyst.

[0003] The main shortcomings of the prior art are as follows:

[0004] (1) Large amount of metal ion leaching and poor stability. In the application process of supported catalysts, the metal active components are prone to leaching due to unstable structure or insufficient support bonding, especially under harsh reaction conditions such as acidity, high temperature, or oxidation and reduction. Metal ions are more likely to be detached from the surface of the support and enter the reaction system. This not only leads to a decrease in active sites of the catalyst and reduces the catalytic efficiency, but also causes waste of metal resources and may pose a hidden danger to subsequent product separation and environmental safety. In addition, the continuous loss of metal ions also shortens the service life of the catalyst, affects its repeated use performance, and limits its long-term stable operation in industrial catalytic processes.

[0005] (2) Catalyst deactivation and short service life. Due to factors such as metal particle agglomeration, active site coverage, support structure collapse, or poisoning, traditional catalysts are prone to deactivation after long-term operation or multiple cycles. Especially under high-temperature calcination, strong acid / strong base environment, or free radical attack, metal oxides may undergo crystal transformation or aggregation and grow, significantly reducing their specific surface area and surface active site density, and seriously affecting the activity and selectivity of the catalytic reaction. Catalyst deactivation not only reduces the processing efficiency, but also increases the replacement frequency and operating cost, restricting its promotion in practical engineering applications.

[0006] (3) High environmental pollution risk in the process. The preparation and use of existing catalysts involve a large amount of strong acid, strong base, or organic solvent. If these reagents are not effectively treated before discharge, they will cause serious pollution to water and soil. At the same time, during the regeneration or recovery of the catalyst, the leaching of a large amount of metal ions may also cause heavy metal pollution problems, posing potential ecological risks. In addition, high-temperature calcination, roasting, and other process steps will release nitrogen oxides, sulfur oxides, and volatile organic pollutants, further exacerbating the pressure of air pollution control. Therefore, developing a green, low-pollution, and environmentally friendly catalyst preparation and use process is an urgent need for the development of environmentally friendly catalytic materials.

[0007] Therefore, it is urgent to develop a new catalyst preparation method, which can realize high dispersion and stable anchoring of metal components on the surface of the carrier under the premise of ensuring high loading capacity, thereby comprehensively improving the catalytic performance and meeting the needs of complex application scenarios such as industrial wastewater treatment. SUMMARY

[0008] Therefore, the purpose of the present application is to provide a preparation method of a supported catalyst. The preparation method provided by the present application solves the problems of metal agglomeration and uneven distribution commonly found in traditional impregnated catalysts, and provides a new technical path for the design and preparation of high-performance supported catalysts.

[0009] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0010] One of the technical solutions of the present application is a preparation method of a supported catalyst, comprising the following steps:

[0011] uniformly dispersing a metal oxide precursor in a polymer solution to obtain a mixture;

[0012] shaping the mixture, and then drying and calcining to obtain the supported catalyst;

[0013] The metal oxide precursor is an oxide precursor of iron and an oxide precursor of copper.

[0014] The second technical solution of the present application is a supported catalyst prepared by the above-mentioned preparation method.

[0015] The third technical solution of the present application is an application of the above-mentioned supported catalyst in degrading OTSA (o-toluenesulfonamide) in water.

[0016] The present application discloses the following technical effects:

[0017] The present application innovatively selects a high molecular polymer material as a catalyst carrier, and prepares a customized activated carbon based on its structural characteristics. Compared with ordinary activated carbon on the market, this kind of customized carrier shows more excellent chemical stability, mechanical strength and thermal stability, and can still maintain good structural integrity in high temperature and high pressure or complex reaction systems.

[0018] The present application realizes the high dispersion of metal oxides on the surface of the carrier. This highly uniform metal distribution mode not only improves the density of the catalytic active sites, but also significantly enhances the stability of the metal components during use, effectively preventing metal agglomeration and loss, thereby ensuring the long-term operation of the catalyst in various industrial scenarios. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed in the embodiments. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative effort.

[0020] Figure 1 Effect of different substrate concentrations on the performance of catalysts in removing OTSA in Example 1;

[0021] Figure 2 Effect of different reaction systems on the performance of OTSA removal in Example 2;

[0022] Figure 3 SEM images of the catalyst in Example 2, wherein (a) is the SEM image of ZnFe2Cu2Ox / GAC before reaction, and (b) is the SEM image of ZnFe2Cu2Ox / GAC after reaction;

[0023] Figure 4 EDS image of the catalyst in Example 2;

[0024] Figure 5 Reuse times of the catalyst in Example 2 and Example 3;

[0025] Figure 6 Continuous degradation test of the catalyst in Example 2. DETAILED DESCRIPTION

[0026] The detailed description of the various exemplary embodiments of the present application should not be considered to limit the present application, but should be understood to describe some aspects, features and embodiments of the present application in more detail.

[0027] It should be understood that the terms described in the present application are only for describing the specific embodiments, and are not used to limit the present application. In addition, for the numerical range in the present application, it should be understood that each intermediate value between the upper limit and the lower limit of the range is also specifically disclosed. Each smaller range between any stated value or intermediate value in the stated range, and any other stated value or intermediate value in the stated range, is also included in the present application. The upper limit and the lower limit of these smaller ranges can be independently included or excluded from the range.

[0028] All technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains, unless indicated otherwise. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application, the preferred methods and materials are described. All documents mentioned herein are incorporated by reference to disclose and describe in full the methods and / or materials which are described therein. In case of conflict between the content of the specification and that of any document incorporated herein by reference, the content of the specification prevails.

[0029] Many modifications and variations of this application can be made in the light of the above teachings without departing from the spirit or scope of the application. Other implementations of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. The specification and examples given are exemplary only.

[0030] As used herein, the terms "comprises", "comprising", "includes", "including", "has", "having", "contains", "containing", or variations thereof, are intended to be open-ended terms that mean inclusion, but not limited to, the listed materials and methods.

[0031] Unless otherwise specified, room temperature in the present application means 25±5℃.

[0032] The present application mainly solves the following technical problems:

[0033] (1) Loading capacity and dispersion problem: In the traditional impregnation method, there is obvious limitation in the loading capacity of metal ions on the surface of the carrier, and it is difficult to achieve uniform distribution under high loading. In order to improve the loading capacity, multiple impregnation-drying-calcination cycles are usually required, which not only increases the process complexity, but also significantly increases the production cost. More importantly, the distribution of metal ions on the carrier is often uneven, which is easy to cause local enrichment or agglomeration, resulting in uneven distribution of active sites, thereby affecting the overall catalytic performance and reaction stability of the material. For example, in actual catalytic reaction, this non-uniform dispersion state will significantly reduce the selectivity and conversion efficiency of the reaction.

[0034] (2) The influence of high temperature treatment on the structure of the carrier further limits the dispersion of the metal: High temperature calcination process is easy to cause changes in the structure of the carrier, such as pore collapse and decrease in specific surface area, which weakens its carrying capacity and dispersion effect of metal ions. Taking porous ceramic carrier as an example, its porosity and pore size distribution may change after high temperature treatment, which is not conducive to the uniform loading and stable distribution of metal ions, and further affects the subsequent catalytic reaction. In addition, with the increase of temperature, the aggregation trend of metal ions on the surface of the carrier is intensified, which further reduces the uniformity and accessibility of the catalytic active center.

[0035] (3) Metal species morphology is uncontrollable, affecting dispersion and catalytic activity: During calcination, the oxidation state and form of metal ions are difficult to accurately control, and various oxide or complex forms are easily generated. These different forms of metal species exhibit differential activity and selectivity in catalytic reactions, posing challenges to the consistent control of catalyst performance. At the same time, high-temperature conditions can easily lead to the agglomeration or sintering of metal particles, resulting in an increase in particle size and a decrease in specific surface area, significantly reducing their catalytic activity. Especially in catalytic systems that rely on highly dispersed and nanoscale metal particles, such problems will seriously affect reaction efficiency and product selectivity.

[0036] (4) Complex preparation process, making it difficult to achieve controlled dispersion of metal ions: The impregnation-calcination method for preparing supported catalysts involves fine-tuning of multiple key parameters, including impregnation solution concentration, time, drying rate, calcination temperature and time, etc. Any fluctuation in any of these parameters can significantly affect the final dispersion of metal on the support and catalytic performance, thus placing high demands on equipment precision and process control level. In addition, this method often requires the use of high-purity metal salt precursors and high-temperature treatment devices, and multiple rounds of repeated operations are often required to improve metal loading and dispersion, resulting in high energy consumption, long cycle time and rising production costs.

[0037] (5) Large environmental impact, limiting green development: The metal salt solution used in the impregnation process usually contains a large amount of impurity ions, which can easily produce wastewater containing heavy metal ions during the washing step. If not properly treated before discharge, it will cause serious pollution to the ecological environment. At the same time, harmful gases such as nitrogen oxides and sulfur oxides may be released during the calcination stage, especially when the metal salt or support component decomposes or reacts at high temperatures, which requires the additional installation of a waste gas treatment system, further increasing environmental protection pressure and treatment costs.

[0038] To solve the above problems, the first aspect of the present application provides a method for preparing a supported catalyst, comprising the following steps:

[0039] dispersing a metal oxide precursor uniformly in a polymer solution to obtain a mixture;

[0040] shaping the mixture, followed by drying and calcination to obtain the supported catalyst;

[0041] The metal oxide precursor is an iron oxide precursor and a copper oxide precursor.

[0042] In a preferred embodiment of the present application, the iron oxide precursor is selected from iron or an iron oxide; the copper oxide precursor is selected from copper or a copper oxide; and the molar ratio of iron and copper in the iron oxide precursor and the copper oxide precursor is 1:1 to 5:1.

[0043] Specifically, the molar ratio of iron and copper in the iron oxide precursor and the copper oxide precursor is 1:1, 2:1, 3:1, 4:1 or 5:1.

[0044] In the catalyst preparation process, the metal oxide is used as the precursor of iron and copper to replace the traditional metal salt precursor. The metal oxide is widely available and stable in nature. In the calcination process, the nanoscale iron-based or copper-based oxide particles can be generated in situ, and the dispersion state of the metal on the surface of the carrier is effectively improved, and the aggregation trend of the metal particles in the high-temperature process is inhibited.

[0045] The experimental results show that the catalyst prepared by using the metal oxide as the precursor not only has good structural stability and active site distribution, but also has excellent H2O2 activation capacity and free radical generation efficiency in the Fenton-like reaction system, which significantly improves the catalytic oxidation performance. The precursor selection strategy simplifies the preparation process, reduces the transportation and storage cost of the precursor, and provides a more feasible technical path for the large-scale preparation and industrial application of the catalyst under the premise of ensuring high performance of the catalyst.

[0046] In the preferred embodiment of the present application, the metal oxide precursor further comprises component M; the component M is a metal M or an oxide of the metal M; the metal M is selected from zinc, cerium, platinum, palladium, ruthenium, nickel, cobalt, manganese, lanthanum or yttrium; and the molar ratio of the metal element in the component M to the iron element in the iron oxide precursor is 0.01:1 to 1:1.

[0047] Specifically, the molar ratio of the metal element in the component M to the iron element in the iron oxide precursor is 0.01:1, 0.05:1, 0.1:1, 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1 or 1:1.

[0048] The present application uses Fe and Cu as catalytically active components, and adds metal element M as a co-catalyst component of Fe and Cu, thereby improving the removal efficiency of organic pollutants in water through the synergistic effect between the metal element M and Fe and Cu.

[0049] In the preferred embodiment of the present application, the solute of the polymer solution is one or more of polyether sulfone, polysulfone, polyphenylene sulfide, polyimide and polycarbonate, and the solvent is one or more of N,N-dimethylacetamide, N,N-dimethylformamide, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane and acetonitrile.

[0050] The application innovatively selects a series of organic solvents with excellent solubility and thermal stability to uniformly mix with high polymer organic materials such as polyether sulfone, polysulfone, polyphenylene sulfide, polyimide and polycarbonate, and constructs a composite catalyst carrier system with stable structure and excellent performance. The above-mentioned organic solvents play a key role in the fusion process with the high polymer materials due to their unique chemical structure and good solubility. They can not only effectively dissolve the high polymer matrix to form a uniform and stable solution system, but more importantly, provide an ideal dispersion environment for the subsequent introduction of metal oxide precursors, significantly improving the uniformity of metal species distribution on the surface of the carrier.

[0051] In the preferred embodiment of the application, the concentration of the polymer solution is 1-20wt%; the ratio of metal elements in the metal oxide precursor to the polymer solution is 0.1-1mol:100mL.

[0052] Specifically, the concentration of the polymer solution is 1wt%, 5wt%, 10wt%, 15wt% or 20wt%; the ratio of metal elements in the metal oxide precursor to the polymer solution is 0.1mol:100mL, 0.2mol:100mL, 0.3mol:100mL, 0.4mol:100mL, 0.5mol:100mL, 0.6mol:100mL, 0.7mol:100mL, 0.8mol:100mL, 0.9mol:100mL or 1mol:100mL.

[0053] In the loading process, the application controls the addition ratio of the metal oxide precursor to make the metal components highly uniformly distributed in the polymer matrix with different mass fractions. This process realizes effective anchoring and spatial isolation of metal ions, significantly reduces the risk of agglomeration and leaching of the metal ions during use, thereby improving the structural stability of the catalyst and the utilization rate of active sites.

[0054] In the preferred embodiment of the application, the forming method is extrusion forming; and the solidification bath used in the extrusion forming is water.

[0055] In the preferred embodiment of the application, the drying temperature is 70-125℃, and the time is 8-12h; the calcination temperature is 300-800℃, and the time is 1-4h.

[0056] Specifically, the calcination temperature is 300℃, 400℃, 500℃, 600℃, 700℃ or 800℃; and the time is 1h, 2h, 3h or 4h.

[0057] In the calcination process of the present application, controlling the calcination temperature and time is crucial for obtaining metal oxide particles with good dispersibility and high catalytic activity. If the calcination temperature is higher than the above-mentioned preferred range (e.g. higher than 800℃) or the time is too long (e.g. more than 4h), it can lead to excessive carbonization of the polymer matrix or agglomeration and grain growth of the metal oxide particles, thus reducing the specific surface area, decreasing the number of active sites, and weakening the catalytic performance. In addition, too high temperature or too long time can also cause energy waste and increase the preparation cost. If the calcination temperature is lower than the preferred range (e.g. lower than 300℃) or the time is insufficient (e.g. less than 1h), it can lead to incomplete conversion of the metal precursor, residual organic solvent, and poor dispersibility of the metal oxide, which will also reduce the activity and stability of the catalyst. Therefore, controlling the appropriate calcination temperature and time (e.g. 400℃, constant temperature for 1h) helps to generate in-situ nanoscale, highly dispersed metal oxide particles on the surface of the carrier, increases the active site density and the contact efficiency of reactants, and thus significantly enhances the overall performance of the catalyst.

[0058] In the preferred embodiment of the present application, after the calcination is completed, the steps of washing and drying are further included.

[0059] The second aspect of the present application provides a supported catalyst prepared by the above preparation method. It is denoted as MFe2Cu2O x / GAC, wherein M represents zinc, cerium, platinum, palladium, ruthenium, nickel, cobalt, manganese, lanthanum or yttrium.

[0060] The third aspect of the present application provides an application of the above supported catalyst in degrading OTSA in water.

[0061] In the preferred embodiment of the present application, when the above supported catalyst is used to degrade OTSA in water, the dosage of the catalyst is 10% to 100% (V / V), the dosage of H2O2 is 50 to 100 mL / L, the microwave power is 500 to 900 W, the microwave action time is 2 to 10 min, and the pH of the reaction system is 2 to 10.

[0062] The technical solutions of the present application, if not specifically stated, are conventional solutions in the art. The reagents or raw materials used, if not specifically stated, are purchased from commercial channels or are already disclosed.

[0063] In order to better understand the present application, the following examples further illustrate the content of the present application, but the content of the present application is not limited to the following examples.

[0064] Example 1

[0065] Preparation of single-metal supported catalyst:

[0066] (1) Zn, Ni, La were dispersed in 20wt% polysulfone (PSF) solution respectively to obtain a mixture; wherein, the concentration of the polysulfone (PSF) solution was 20wt%, the solute was polysulfone (PSF), and the solvent was N,N-dimethylformamide; the ratio of Zn to the polysulfone (PSF) solution was 0.03mol:100mL, the ratio of Ni to the polysulfone (PSF) solution was 0.03mol:100mL, and the ratio of La to the polysulfone (PSF) solution was 0.03mol:100mL;

[0067] (2) The mixture was transferred to a piping bag, and was slowly extruded into a continuous line in deionized water to complete preliminary shaping by means of a water coagulation bath; then the shaped material was placed in water for 8 hours of water bath treatment to further enhance its structural stability and mechanical strength;

[0068] (3) The shaped material was taken out and cut into granular samples of similar size, and was transferred to a constant temperature drying oven for drying at 125℃ for 12h to realize hardening and desolvation treatment of the material; then the dried granules were placed in a muffle furnace for calcination at 400℃ for 1h in an air atmosphere to remove residual organic components and complete in-situ generation and stable loading of metal oxides;

[0069] (4) After calcination, the catalyst sample was cooled, and then was washed with deionized water to remove surface residual ash and interfering ions that might affect the catalytic performance, and finally the washed catalyst was transferred to a drying oven for drying and storage, to obtain the catalysts, which were respectively recorded as Zn / GAC, Ni / GAC, and La / GAC.

[0070] Performance verification:

[0071] (1) Influence of different concentrations

[0072] To further study the influence of substrate concentration on the removal performance of OTSA, under the conditions of constant catalyst filling amount (80% (V / V)), H2O2 dosage (100mL), and MW (6min) action time, the change trend of OTSA initial concentration on the degradation efficiency under different metal catalytic systems was investigated in 100mL OTSA solution. Figure 1 It can be seen that as the initial concentration of OTSA increases, its removal rate shows a significant downward trend.

[0073] Among the tested metal systems, the catalytic activity of Zn, Ni and La ranked as Zn > Ni > La. When the OTSA concentration was 5 g / L, the removal rates of OTSA by the three metals were 90.2%, 88.0% and 84.8%, respectively; while at a higher concentration of 25 g / L, the removal rates decreased to 39.8%, 40.2% and 58.8%, respectively. The above results show that the increase of substrate concentration significantly inhibited the catalytic reaction, and different metals showed different resistance to concentration interference. Under the premise of constant active species generation rate, lower initial concentration of OTSA means that relatively more active radicals (such as ·OH) per unit volume can be used to attack target pollutant molecules, thereby achieving higher removal efficiency. On the contrary, under high concentration conditions, due to the large increase in the number of substrate molecules, the limited active species are difficult to respond fully, resulting in a decrease in overall removal efficiency. In addition, higher concentration of OTSA is more likely to be adsorbed on the catalyst surface, occupying the activation sites of H2O2, thereby affecting its effective decomposition and reducing the generation efficiency of active species. Although high concentration of substrate may quickly capture active species at the initial stage of the reaction, increasing the local reaction rate, but due to the inhibition of H2O2 activation and the decrease of unexcited H2O2 due to thermal loss and other factors, ultimately leading to a decrease in overall removal efficiency.

[0074] Example 2

[0075] Preparation of multi-element supported catalyst:

[0076] (1) 0.03 mol of Zn, 0.06 mol of Fe and 0.06 mol of Cu were uniformly dispersed in 100 mL of a polysulfone solution to obtain a mixture; wherein the concentration of the polysulfone solution was 20 wt%, the solute was polysulfone, and the solvent was N,N-dimethylformamide;

[0077] (2) The mixture was transferred to a pastry bag, slowly extruded to form a continuous line into deionized water, and the preliminary shaping was completed with the help of the water coagulation bath; then the shaped material was placed in water for 8 hours of water bath treatment to further enhance its structural stability and mechanical strength;

[0078] (3) The shaped material was taken out and cut into granular samples with similar sizes, transferred to a constant temperature drying oven, dried at 125°C for 12 h to achieve hardening and desolvation treatment of the material. Then the dried granules were placed in a muffle furnace and calcined at 400°C for 1 h in air atmosphere to remove residual organic components and complete in-situ generation and stable loading of metal oxides;

[0079] (4) After calcination, the catalyst sample is cooled and then washed with deionized water to remove residual ash and interfering ions that may affect the catalytic performance. Finally, the washed catalyst is transferred to a drying oven for drying and storage, and the catalyst is denoted as ZnFe2Cu2Ox / GAC.

[0080] The preparation method is the same as that for ZnFe2Cu2Ox / GAC, except that the addition of Zn, Fe, and Cu is omitted. The resulting catalyst is denoted as GAC.

[0081] Performance verification

[0082] (1) The influence of different reaction systems

[0083] To systematically study the effects of different reaction systems on OTSA removal performance, comparative experiments were conducted under single-factor and multi-factor synergistic conditions (in the experiments, 100 mL of 10 g / L OTSA solution, 100 mL of H2O2, 80% (V / V) of GAC, and 80% (V / V) of ZnFe2Cu2Ox / GAC). The experimental results showed that ( Figure 2 ), using only MW (microwave, power 700W, action time 6min), H2O2, GAC or ZnFe2Cu2O x When / GAC is used as the reaction system, the removal rate of OTSA is extremely low, with almost no significant change. This indicates that in a single-factor reaction system, the simple thermal effect, adsorption, and direct oxidation by H2O2 have almost no promoting effect on the degradation of OTSA, and cannot achieve effective pollutant removal.

[0084] In a two-factor reaction system, including MW+GAC and MW+ZnFe2Cu2O x / GAC, MW+H2O2, H2O2+GAC and H2O2+ZnFe2Cu2O x Combining MW with GAC and other additives improves OTSA removal efficiency. Specifically, the introduction of MW increases the removal efficiency of the H2O2 oxidation system from 3.5% to 4.1%. More significantly, the interaction between MW and the catalyst surface generates localized high-temperature hotspots, effectively promoting the activation and degradation of OTSA molecules, thus increasing the removal efficiency by approximately 17.6%. Furthermore, the Fenton-like reactions initiated by the combination of H2O2 and the catalyst (such as H2O2 + GAC and H2O2 + ZnFe2Cu2O) also contribute to this improvement. x The / GAC system also exhibited some catalytic activity, but the overall reaction efficiency remained limited due to the short reaction time. Further research showed that when MW, H2O2, and ZnFe2Cu2O... xThe removal efficiency of OTSA reached the highest level when the three of them cooperated. In 6 minutes of reaction time, MW+ZnFe2Cu2O / GAC+H2O2 system x The mineralization rate of OTSA reached 93.1% in the system of MW+GAC+H2O2. Compared with the system of MW+GAC+H2O2, the removal efficiency of this system increased by about 60%, which fully explained that the Fenton-like reaction between the supported metal oxide catalyst and H2O2 could significantly enhance the degradation effect of OTSA.

[0085] At the same time, compared with the double-factor Fenton-like system, the synergistic effect between MW and ZnFe2Cu2Ox / GAC not only significantly improved the reaction rate, but also effectively shortened the reaction time, and strengthened the whole Fenton-like reaction process. This result verified the superior performance of the MW enhanced Fenton-like catalytic system constructed in the application in the efficient degradation of refractory organic pollutants.

[0086] The microwave enhanced Fenton-like catalytic oxidation mechanism: the core lies in the synergistic enhancement effect between the MW effect and the Fenton-like reaction. Through the thermal effect and non-thermal effect of MW, the generation of active free radicals and the recycling of metal catalysts are promoted, so as to significantly improve the oxidation and degradation efficiency of pollutants. In terms of thermal effect, MW can make the polar molecules (such as water molecules) in the system rotate and vibrate at high speed, generate internal friction heat, realize rapid and uniform heating of the system, thereby accelerating the chemical reaction rate and promoting the decomposition of H2O2 to generate a large number of hydroxyl radicals (·OH) with strong oxidation ability. In addition, MW can also induce the formation of local high-temperature hot spots on the surface of the catalyst, significantly increase the local temperature of the active sites, and further enhance the degradation ability of the catalyst to pollutants. In terms of non-thermal effect, MW can change the electron cloud distribution and chemical bond polarization state of the reactant molecules, effectively reduce the reaction activation energy, and improve the reaction kinetics rate. At the same time, MW can also regulate the electronic structure of the metal active sites on the catalyst surface, enhance the interaction between them and H2O2 and pollutant molecules, and thus improve the catalytic efficiency of Fenton-like reaction. The synergistic effect of the above thermal effect and non-thermal effect not only promotes the generation of ·OH, but also accelerates the decomposition rate of H2O2 and the valence state transformation between metal ions, making the Fenton-like reaction cycle more efficient. In addition, MW also has good mass transfer enhancement effect, which can accelerate the diffusion rate of reactants to the catalyst surface, and promote the desorption of products from the catalyst surface, thereby reducing the mass transfer resistance and comprehensively improving the efficiency of the whole oxidation and degradation process.

[0087] Structure and characterization of the product

[0088] (1) SEM

[0089] The surface morphology of the catalyst was characterized and analyzed by scanning electron microscope (SEM)Figure 3 ) shows that a large number of metal active component particles are uniformly attached to the surface of the carrier, showing a particle group structure formed by gradual aggregation of small crystals, and these particle groups are closely arranged on the surface of the catalyst and are uniformly distributed. The above morphological characteristics preliminarily show that the active components of iron, copper and zinc are successfully loaded on the catalyst.

[0090] Further comparison of the SEM images of the catalyst before and after use shows that the surface morphology of the catalyst after reaction has no obvious difference compared with the fresh catalyst, and there is no obvious particle shedding, agglomeration or structure damage phenomenon. This shows that the catalyst has good structural stability and anti-loss ability during the reaction, can effectively maintain its catalytic activity, has good repeated use performance and application prospect.

[0091] (2) EDS

[0092] The new catalyst was subjected to element distribution analysis by energy dispersive X-ray spectroscopy (EDS) (as shown in Fig. 3). Figure 4 From the provided EDS images, the successful loading of metal ions (iron, copper and zinc) on the carrier can be clearly observed. These images clearly show the presence of target metal elements and their uniform distribution, further confirming that the active components have been effectively loaded on the carrier material.

[0093] The above EDS analysis results fully show that the preparation process of the new catalyst described in the present application is successful, and the prepared catalyst has the expected composition and structural characteristics, laying a solid foundation for subsequent catalytic performance testing and practical application.

[0094] Example 3

[0095] NiFe2Cu2O x / GAC catalyst was prepared in the same way as in Example 2, except that 0.03 mol of Zn, 0.06 mol of Fe and 0.06 mol of Cu were replaced by 0.03 mol of Ni, 0.06 mol of Fe and 0.06 mol of Cu.

[0096] LaFe2Cu2O x / GAC catalyst was prepared in the same way as in Example 2, except that 0.03 mol of Zn, 0.06 mol of Fe and 0.06 mol of Cu were replaced by 0.03 mol of La, 0.06 mol of Fe and 0.06 mol of Cu.

[0097] Performance verification

[0098] (1) In industrial applications, the recovery and reuse of catalysts are key considerations. The relationship between catalyst stability and the number of times it can be reused is crucial for assessing its long-term application potential. According to experimental data Figure 5 , where Zn represents ZnFe2Cu2Ox / GAC, Ni represents NiFe2Cu2O x / GAC, and La represents LaFe2Cu2O x / GAC), the removal rate of OTSA showed a slow downward trend as the number of catalyst reuse increased.

[0099] After the first degradation process was completed, there was a significant decrease in OTSA removal efficiency. However, during subsequent reuse, the downward trend in removal rate gradually leveled off. Specifically, for the ZnFe2Cu2O x / GAC catalyst, the degradation efficiency decreased by 29.1%, 2.2%, 2.7%, and 0.9% in each round, respectively. In contrast, the NiFe2Cu2O x / GAC and LaFe2Cu2O x / GAC catalysts showed a decrease in OTSA removal rate of about 37% and 16% from the first to the fifth round, respectively. It is particularly noteworthy that after five reuses, all three catalysts exhibited excellent stability and sustained degradation capacity. Despite some degree of removal rate decline, all catalysts maintained high OTSA removal efficiency after multiple cycles. This result fully confirms that the ZnFe2Cu2O x / GAC, NiFe2Cu2O x / GAC, and LaFe2Cu2O x / GAC catalysts have excellent reusability and good long-term stability, providing reliable protection for actual industrial applications.

[0100] (2) Continuous operation performance test

[0101] To evaluate the stability and treatment effect of the catalyst prepared in Example 2 of the present invention in actual application, a small-scale test was conducted with the following process conditions: OTSA initial concentration was 50 mg / L, MW power was set to 500 W, MW action time was 1.5 min, H2O2 dosage was 50 mL / L, initial pH of the reaction system was 4.0, carbon column height was 50 cm, and initial temperature was 25℃. OTSA solution was introduced from the bottom of the reaction column, and under the premise of keeping the microwave power and single action time constant, the reaction time and microwave action frequency were adjusted appropriately during different operation cycles.

[0102] The degradation performance change of the catalyst in the continuous operation process was evaluated by measuring the OTSA concentration and COD removal rate in the effluent. Figure 6 As the continuous degradation time gradually extended, the OTSA degradation rate was greater than 70%, and the COD removal efficiency was greater than 65%. The main reasons for the gradual decrease in removal efficiency included: during the continuous operation process, the active components inside the catalyst were gradually consumed, resulting in a decrease in its catalytic ability; at the same time, the catalyst structure may collapse to a certain extent during long-term reaction, affecting its stability and continuous supply of active sites. In addition, due to the continuous addition of H2O2, a large amount of bubbles were generated in the reaction column, causing disturbance of the catalyst bed, so that part of the catalyst particles were lost with the effluent, further reducing the overall removal efficiency.

[0103] Despite the above-mentioned adverse factors, the downward trend of the removal efficiency was relatively gentle, indicating that the catalyst still had good structural stability and catalytic durability under long-term operation conditions, and could maintain relatively stable pollutant removal performance, reflecting its feasibility and advantages in the application of industrial continuous wastewater treatment system.

[0104] The above only describes the preferred embodiments of the present application, and it should be noted that for those skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, and these improvements and refinements should also be considered within the scope of protection of the present application.

Claims

1. A method for preparing a supported catalyst, characterized by, The method comprises the following steps: dispersing metal oxide precursor in polymer solution to obtain a mixture; shaping the mixture, and then drying and calcining to obtain the supported catalyst; the metal oxide precursor is an iron oxide precursor and a copper oxide precursor.

2. The production method according to claim 1, characterized by, the iron oxide precursor is selected from iron or iron oxide; the copper oxide precursor is selected from copper or copper oxide; the molar ratio of iron and copper in the iron oxide precursor and the copper oxide precursor is 1:1-5:

1.

3. The production method according to claim 1, characterized by, the metal oxide precursor further comprises component M; the component M is metal M and / or oxide of metal M; the metal M is at least one selected from zinc, cerium, platinum, palladium, ruthenium, nickel, cobalt, manganese, lanthanum and yttrium; the molar ratio of metal element in the component M and iron element in the iron oxide precursor is 0.01:1-1:

1.

4. The method of claim 1, wherein, the solute of the polymer solution is one or more of polyether sulfone, polysulfone, polyphenylene sulfide, polyimide and polycarbonate; and the solvent is one or more of N,N-dimethylacetamide, N,N-dimethylformamide, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane and acetonitrile.

5. The preparation method according to claim 1, characterized in that, the concentration of the polymer solution is 1-20wt%; the ratio of metal element in the metal oxide precursor to the polymer solution is 0.1-1mol:100mL.

6. The method of claim 1, wherein, the shaping method is extrusion molding; and the solidification bath used in the extrusion molding is water.

7. The preparation method according to claim 1, characterized in that, the drying temperature is 70-125℃, and the time is 8-12h; the calcining temperature is 300-800℃, and the time is 1-4h.

8. The method of claim 1, wherein, after the calcining is completed, the method further comprises the steps of washing and drying. 9.A supported catalyst prepared by the preparation method of any one of claims 1-8. 10.Use of the supported catalyst of claim 9 in degrading OTSA in water.

Images