Preparation method of hierarchical pore MFI type ZSM-5 zeolite molecular sieve material loaded with metal in situ

Abstract

The invention relates to the technical field of synthesis of zeolite molecular sieves, in particular to a preparation method of an in-situ metal-loaded hierarchical pore MFI type ZSM-5 zeolite molecular sieve material. The method comprises the following steps: 1, adding a trivalent aluminum source and a hydroxyl ion source into deionized water, and stirring to obtain a clear solution; 2, adding a tetravalent silicon source into the clear solution, stirring, adding a molecular sieve template agent and a boron source, stirring, and adding a metal complex solution to obtain a mixed solution; 3, mixing the mixed solution with commercial sponge in a hydrothermal reaction kettle, and crystallizing through hydrothermal reaction; 4, after crystallization is finished, quenching, filtering, centrifuging, washing and drying the mixture in the reaction kettle to obtain a crystallized product; and 5, calcining the crystallized product. The method has the advantages of simple production process, cheap and easily available raw materials, low energy consumption, high product crystallinity, low production cost and good economic benefit, and is suitable for batch production.

Description

Technical field:

[0001] The invention relates to the technical field of zeolite molecular sieve synthesis, and in particular to a method for preparing a multi-level pore MFI type ZSM-5 zeolite molecular sieve material with in-situ metal loading. Background technology:

[0002] Multi-level molecular sieves combine the inherent catalytic properties of microporous molecular sieves with the enhanced mass transfer capacity of additional mesoporous and / or macroporous systems. They are the most ideal catalysts and adsorbents in industry and have become a highly developed field of current important interest. In addition to the enhanced mass transfer capacity leading to high activity, selectivity and cycle time, another fundamental advantage of the hierarchical structure in zeolite materials is that it can significantly improve the utilization efficiency of zeolite materials, thereby minimizing energy, time and raw material consumption. The pores of multi-level molecular sieves are more open, with a larger specific surface area and more contact acid sites, which are conducive to the diffusion of reactants, reactions and products, and have developed new ways to achieve the effect of improving catalytic performance. Therefore, zeolites with multi-level pores and adjustable acid sites are very useful in industry.

[0003] Hui Li et al. proposed a solvent-free synthesis of well-dispersed multifaceted siliceous ZSM-5 (Si-ZSM-5) crystals, which also exhibited preferential growth along the c-axis and hierarchical porous structures. The morphological control of Si-ZSM-5 crystals was achieved by the selective interaction of graphene oxide (GO) sheets with different crystal faces, and these interactions were verified by molecular dynamics (MD) simulations. In addition, Si-ZSM-5 crystals exhibited hierarchical porous structures due to the encapsulation of graphene oxide flakes (Li, H.; Liu, X.; Qi, S.; Xu, L.; Shi, G.; Ding, Y.; Yan, X.; Huang, Y.; Geng, J., Graphene Oxide Facilitates Solvent-Free Synthesis of Well-Dispersed, Faceted Zeolite Crystals. Angew Chem Int Ed Engl 2017, 56 (45), 14090-14095.). However, the price of graphene oxide sheets is not so economical, thus limiting large-scale mass production applications. Deng, Z dispersed the required amount of carbon nanotubes in ethanol by ultrasonic treatment, and then added tetraethyl orthosilicate (TEOS) and stirred. Aluminum isopropoxide (AIP) was dissolved in tetrapropylammonium hydroxide (TPAOH, 25 wt%) solution and then diluted with ethanol to prepare an ethanol solution. Subsequently, the ethanol solution was added to the above carbon nanotube suspension. The resulting suspension was stirred at room temperature to complete the hydrolysis of TEOS, and then the mixture was dispersed in a Petri dish to allow the solvent to evaporate. The prepared black dry gel was transferred to a Teflon cup and subjected to 72 hours at 170 ° C. The product is washed, air-dried, and finally calcined to remove TPA and CNT to obtain hierarchical ZSM-5 (Deng, Z.; Zhang, Y.; Zhu, K.; Qian, G.; Zhou, X., Carbon nanotubes as transient inhibitors in steam-assisted crystallization of hierarchical ZSM-5zeolites. Materials Letters 2015, 159, 466-469.). The price of carbon nanotubes is 450,000 to 550,000 yuan per ton, which is not economical enough. Although the synthetic molecular sieves mentioned in the above references have made breakthroughs in reducing diffusion restrictions, the key materials used in the synthetic molecular sieves are either complex in structure or too expensive to purchase, the synthesis cost is high, and the economic benefits are poor, which limits mass production and is difficult to apply to large-scale industrial production. Summary of the invention:

[0004] The technical problem to be solved by the present invention is to provide a method for preparing a multi-level porous MFI type ZSM-5 zeolite molecular sieve material with in-situ metal loading, which realizes a simple production process, cheap and readily available raw materials, low energy consumption, high product crystallinity, low production cost, good economic benefits, and is suitable for batch production, thus overcoming the disadvantage of the high synthesis cost of existing molecular sieves.

[0005] The technical solution adopted by the present invention is: a method for preparing a multi-level porous MFI type ZSM-5 zeolite molecular sieve material with in-situ metal loading, the method steps are as follows:

[0006] 1. Add trivalent aluminum source and hydroxide ion source into deionized water and stir to obtain a clear solution;

[0007] 2. adding a tetravalent silicon source to the above clarified solution and stirring, then adding a molecular sieve template and a boron source and stirring, and then adding a metal complex solution to obtain a mixed solution;

[0008] 3. Mixing the above mixed solution with a commercial sponge in a hydrothermal reactor to crystallize through a hydrothermal reaction;

[0009] 4. After the crystallization is completed, the mixture in the reaction kettle is quenched, filtered, centrifuged, washed, and dried to obtain a crystallized product;

[0010] 5. calcining the above crystallized product to obtain a multi-level porous MFI type ZSM-5 zeolite molecular sieve material loaded with metal in situ;

[0011] Among them, the molar ratio of silicon element in the tetravalent silicon source to aluminum element in the trivalent aluminum source is 150-20:1; the molar ratio of boron ions in the boron source to silicon element in the tetravalent silicon source is 0.05-0.2:1; the molar ratio of tetrapropylammonium bromide in the molecular sieve template solution to silicon element in the tetravalent silicon source is 0.1-0.2:1.

[0012] Furthermore, the tetravalent silicon source is one or more of white carbon black, silica sol, and tetraethyl orthosilicate, the trivalent aluminum source is one or more of sodium aluminate, aluminum hydroxide, aluminum nitrate, and aluminum sulfate, the hydroxide ion source is sodium hydroxide or potassium hydroxide, and the boron source is one or more of boric acid and borates.

[0013] Furthermore, the tetravalent silicon source is silica sol, the trivalent aluminum source is one or more of sodium aluminate and aluminum hydroxide, and the boron source is boric acid.

[0014] Furthermore, the mass fraction of tetrapropylammonium bromide in the molecular sieve template solution is 98%.

[0015] Furthermore, the reaction temperature of the hydrothermal reaction in step three is 135° C. to 200° C., and the hydrothermal reaction time is 48 to 168 hours.

[0016] Furthermore, the reaction temperature of the hydrothermal reaction in step three is 150° C. to 180° C., and the hydrothermal reaction time is 72 hours.

[0017] Furthermore, the crystallized product in step 4 is dried in a forced air drying oven at a drying temperature of 50° C. to 100° C. for 10 to 48 hours.

[0018] Furthermore, in step 4, the crystallized product is dried in a forced air drying oven at a drying temperature of 60° C. to 90° C. for 12 to 40 hours.

[0019] Furthermore, the calcination of the crystallized product in step 5 is to raise the temperature of the crystallized product from room temperature to 500-550° C. in flowing air and keep the temperature for 5-6 hours.

[0020] The beneficial effects of the present invention are:

[0021] 1. The present invention uses a simple, inexpensive and easily purchased commercial sponge as a zeolite growth regulator, and does not require surfactants and various pretreatment processes to synthesize a multi-level porous MFI type ZSM-5 zeolite molecular sieve material with in-situ metal loading. The production process is simple, the raw materials are cheap and easily available, and the energy consumption is low. The product has high crystallinity, low production cost, good economic benefits, is suitable for mass production, and can be expanded to large-scale industrial applications.

[0022] 2. The MFI type ZSM-5 zeolite molecular sieve material prepared by the preparation method of the in-situ loaded metal multi-level pore MFI type ZSM-5 zeolite molecular sieve material provided by the present invention is obtained by controlling the morphology of the zeolite by adding commercial sponge. Therefore, the in-situ loaded metal multi-level pore MFI type ZSM-5 zeolite molecular sieve material provided by the present invention is a spherical MFI type ZSM-5 zeolite molecular sieve, which is composed of a square structure with a minimum size of several nanometers. Its scanning electron microscope (SEM) photograph shows a spherical structure with a spherical morphology. This multi-level structured MFI type ZSM-5 zeolite molecular sieve material can shorten the diffusion path and improve the catalytic effect. Description of the drawings:

[0023] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] Figure 1 This is the XRD spectrum of the in-situ metal-loaded multi-level pore MFI type ZSM-5 zeolite molecular sieve material prepared in Example 1 of the present invention.

[0025] Figure 2 This is a SEM photograph of the in-situ metal-loaded multi-level pore MFI type ZSM-5 zeolite molecular sieve material prepared in Example 1 of the present invention.

[0026] Figure 3 This is the XRD spectrum of the in-situ metal-loaded multi-level pore MFI type ZSM-5 zeolite molecular sieve material prepared in Example 2-6 of the present invention.

[0027] Figure 4 This is a SEM photograph of the in-situ metal-loaded multi-level pore MFI type ZSM-5 zeolite molecular sieve material prepared in Example 2-6 of the present invention.

[0028] Figure 5 This is the XRD spectrum of the in-situ metal-loaded multi-level pore MFI type ZSM-5 zeolite molecular sieve material prepared in Example 7 of the present invention.

[0029] Figure 6 This is a SEM photograph of the in-situ metal-loaded multi-level pore MFI type ZSM-5 zeolite molecular sieve material prepared in Example 7 of the present invention. Specific implementation method:

[0030] Example 1

[0031] A method for preparing a multi-level porous MFI type ZSM-5 zeolite molecular sieve material with in-situ metal loading comprises the following steps:

[0032] (1) Add NaOH solid and NaAlO2 to 40.395 g of deionized water, turn on the magnetic stirrer, set the speed to 500 rpm until a clear solution is obtained;

[0033] (2) HS-40 is then added to the clear solution obtained in the previous step, using silicic acid as a silicon source, in an amount such that the molar ratio of silicon to aluminum is 20:1. After the silicon source is added dropwise, it can be observed that the clear solution in the beaker gradually becomes turbid, accompanied by a significant increase in the viscosity of the system.

[0034] (3) After adding the silicic acid, add TPABR and H3BO3, wherein the molar ratio of boron ion to silicon element is 0.05:1, and the molar ratio of TPABR to silicon element is 0.1:1. Seal the plastic beaker with wax film and continue stirring for 3 hours at room temperature. After three hours, add 1.8 ml of the prepared ethylenediamine metal complex solution.

[0035] (4) the mixed solution and the commercial sponge were mixed together and then transferred into a hydrothermal reactor for hydrothermal reaction at 180° C. for 2 days;

[0036] (5) After the crystallization is completed, the reactor is taken out and rapidly quenched with running water, the precipitate is separated by filtration, and then centrifuged and washed;

[0037] (6) The product is dried in a forced air drying oven at 70°C for 24 hours, and the crystallized product is calcined. The temperature is rapidly raised from room temperature to 550°C in flowing air and kept at this temperature for 6 hours, thereby obtaining a multi-level pore MFI type ZSM-5 zeolite molecular sieve.

[0038] The XRD spectrum of the obtained multi-level pore MFI type ZSM-5 zeolite molecular sieve is as follows: Figure 1 As shown, from Figure 1 It can be seen that the XRD spectrum of the multi-level pore MFI type ZSM-5 zeolite molecular sieve prepared in the present invention is completely consistent with the standard MFI spectrum and contains characteristic peaks, indicating that the zeolite synthesized in the embodiment of the present invention is a multi-level pore MFI type ZSM-5 zeolite molecular sieve; the SEM photo of the obtained multi-level pore MFI type ZSM-5 zeolite molecular sieve is shown in Figure 2 As shown, it can be seen from the SEM photograph that the structure of the multi-level pore MFI type ZSM-5 zeolite molecular sieve prepared in the embodiment of the present invention is indeed spherical or ellipsoidal.

[0039] Example 2

[0040] A method for preparing a multi-level porous MFI type ZSM-5 zeolite molecular sieve material with in-situ metal loading comprises the following steps:

[0041] (1) Add NaOH solid and NaAlO2 to 11.67 g of deionized water, turn on the magnetic stirrer, set the speed to 500 rpm until a clear solution is obtained;

[0042] (2) HS-40 is then added to the clear solution obtained in the previous step, with the silicon source silicic acid being added in an amount such that the molar ratio of silicon element to aluminum element is 50:1. After the silicon source is added dropwise, it can be observed that the clear solution in the beaker gradually becomes turbid, accompanied by a significant increase in the viscosity of the system;

[0043] (3) After adding the silicic acid, add TPABR and H3BO3, wherein the molar ratio of boron ion to silicon element is 0.05:1, and the molar ratio of TPABR to silicon element is 0.1:1. Seal the plastic beaker with wax film and continue stirring for 3 hours at room temperature. After three hours, add 1.8 ml of the prepared ethylenediamine metal complex solution.

[0044] (4) the mixed solution was mixed with a commercial sponge and then transferred into a hydrothermal reactor for a hydrothermal reaction at 180° C. for 2 days;

[0045] (5) After the crystallization is completed, the reactor is taken out and rapidly quenched with running water, and the precipitate is separated by filtration, and then centrifuged and washed;

[0046] (6) The product is dried in a forced air drying oven at 70°C for 24 hours, and the crystallized product is calcined. The temperature is rapidly raised from room temperature to 550°C in flowing air and kept at this temperature for 6 hours, thereby obtaining a multi-level pore MFI type ZSM-5 zeolite molecular sieve loaded with metallic palladium in situ.

[0047] The XRD spectrum of the obtained in-situ loaded metal multi-level pore MFI type ZSM-5 zeolite molecular sieve is as follows: Figure 3 As shown, from Figure 3 It can be seen that the XRD spectrum of the in-situ metal-loaded multi-level pore MFI type ZSM-5 zeolite molecular sieve prepared in the embodiment of the present invention is completely consistent with the standard MFI spectrum and contains characteristic peaks, indicating that the zeolite synthesized in the embodiment of the present invention is an in-situ metal-loaded multi-level pore MFI type ZSM-5 zeolite molecular sieve; the SEM photo of the obtained in-situ metal-loaded multi-level pore MFI type ZSM-5 zeolite molecular sieve is shown in FIG. Figure 4 As shown, it can be seen from the SEM photo that the structure of the in-situ metal-loaded multi-level porous MFI type ZSM-5 zeolite molecular sieve prepared in the embodiment of the present invention is indeed ellipsoidal.

[0048] Example 3

[0049] A method for preparing a multi-level porous MFI type ZSM-5 zeolite molecular sieve material with in-situ metal loading comprises the following steps:

[0050] (1) Add NaOH solid and NaAlO2 to 11.67 g of deionized water, turn on the magnetic stirrer, set the speed to 500 rpm until a clear solution is obtained;

[0051] (2) HS-40 is then added to the clear solution obtained in the previous step, with the silicon source silicic acid being added in an amount such that the molar ratio of silicon element to aluminum element is 50:1. After the silicon source is added dropwise, it can be observed that the clear solution in the beaker gradually becomes turbid, accompanied by a significant increase in the viscosity of the system;

[0052] (3) After adding the silicic acid, add TPABR and H3BO3, wherein the molar ratio of boron ion to silicon element is 0.15:1, and the molar ratio of TPABR to silicon element is 0.1:1. Seal the plastic beaker with wax film and continue stirring for 3 hours at room temperature. After three hours, add 1.8 ml of the prepared ethylenediamine metal complex solution.

[0053] (4) the mixed solution and the commercial sponge were mixed together and then transferred into a hydrothermal reactor for hydrothermal reaction at 180° C. for 2 days;

[0054] (5) After the crystallization is completed, the reactor is taken out and rapidly quenched with running water, the precipitate is separated by filtration, and then centrifuged and washed;

[0055] (6) The product is dried in a forced air drying oven at 70°C for 24 hours, and the crystallized product is calcined. The temperature is rapidly raised from room temperature to 550°C in flowing air and kept at this temperature for 6 hours, thereby obtaining a multi-level pore MFI type ZSM-5 zeolite molecular sieve loaded with metallic palladium in situ.

[0056] The XRD spectrum of the obtained in-situ loaded metal multi-level pore MFI type ZSM-5 zeolite molecular sieve is as follows: Figure 3 As shown, from Figure 3 It can be seen that the XRD spectrum of the in-situ metal-loaded multi-level pore MFI type ZSM-5 zeolite molecular sieve prepared in the embodiment of the present invention is completely consistent with the standard MFI spectrum and contains characteristic peaks, indicating that the zeolite synthesized in the embodiment of the present invention is an in-situ metal-loaded multi-level pore MFI type ZSM-5 zeolite molecular sieve; the SEM photo of the obtained in-situ metal-loaded multi-level pore MFI type ZSM-5 zeolite molecular sieve is shown in FIG. Figure 4 As shown, it can be seen from the SEM photo that the structure of the in-situ metal-loaded multi-level porous MFI type ZSM-5 zeolite molecular sieve prepared in the embodiment of the present invention is indeed ellipsoidal.

[0057] Example 4

[0058] A method for preparing a multi-level porous MFI type ZSM-5 zeolite molecular sieve material with in-situ metal loading comprises the following steps:

[0059] (1) Add NaOH solid and NaAlO2 to 11.67 g of deionized water, turn on the magnetic stirrer, set the speed to 500 rpm until a clear solution is obtained;

[0060] (2) HS-40 is then added to the clear solution obtained in the previous step, with the silicon source silicic acid being added in an amount such that the molar ratio of silicon element to aluminum element is 50:1. After the silicon source is added dropwise, it can be observed that the clear solution in the beaker gradually becomes turbid, accompanied by a significant increase in the viscosity of the system;

[0061] (3) After adding the silicic acid, add TPABR and H3BO3, wherein the molar ratio of boron ion to silicon element is 0.2:1, and the molar ratio of TPABR to silicon element is 0.1:1, and then seal the plastic beaker with wax film, continue stirring, and stir at room temperature for 3 hours; after three hours, add 1.8 ml of the prepared ethylenediamine metal complex solution;

[0062] (4) the mixed solution was mixed with a commercial sponge and then transferred into a hydrothermal reactor for a hydrothermal reaction at 180° C. for 2 days;

[0063] (5) After the crystallization is completed, the reactor is taken out and rapidly quenched with running water, and the precipitate is separated by filtration, and then centrifuged and washed;

[0064] (6) The product is dried in a forced air drying oven at 70°C for 24 hours, and the crystallized product is calcined. The temperature is rapidly raised from room temperature to 550°C in flowing air and kept at this temperature for 6 hours, thereby obtaining a multi-level pore MFI type ZSM-5 zeolite molecular sieve loaded with metallic palladium in situ.

[0065] The XRD spectrum of the obtained in-situ loaded metal multi-level pore MFI type ZSM-5 zeolite molecular sieve is as follows: Figure 3 As shown, from Figure 3 It can be seen that the XRD spectrum of the in-situ metal-loaded multi-level pore MFI type ZSM-5 zeolite molecular sieve prepared in the embodiment of the present invention is completely consistent with the standard MFI spectrum and contains characteristic peaks, indicating that the zeolite synthesized in the embodiment of the present invention is an in-situ metal-loaded multi-level pore MFI type ZSM-5 zeolite molecular sieve; the SEM photo of the obtained in-situ metal-loaded multi-level pore MFI type ZSM-5 zeolite molecular sieve is shown in FIG. Figure 4 As shown, it can be seen from the SEM photo that the structure of the in-situ metal-loaded multi-level porous MFI type ZSM-5 zeolite molecular sieve prepared in the embodiment of the present invention is indeed ellipsoidal.

[0066] Example 5

[0067] A method for preparing a multi-level porous MFI type ZSM-5 zeolite molecular sieve material with in-situ metal loading comprises the following steps:

[0068] (1) Add NaOH solid and NaAlO2 to 11.67 g of deionized water, turn on the magnetic stirrer, set the speed to 500 rpm until a clear solution is obtained;

[0069] (2) HS-40 is then added to the clear solution obtained in the previous step, with the silicon source silicic acid being added in an amount such that the molar ratio of silicon element to aluminum element is 50:1. After the silicon source is added dropwise, it can be observed that the clear solution in the beaker gradually becomes turbid, accompanied by a significant increase in the viscosity of the system;

[0070] (3) After adding silicic acid, add TPABR and H3BO3, wherein the molar ratio of boron ion to silicon element is 0.15:1, and the molar ratio of TPABR to silicon element is 0.2:1, and then seal the plastic beaker with wax film, continue stirring, and stir at room temperature for 3 hours; after three hours, add 1.8 ml of the prepared ethylenediamine metal complex solution;

[0071] (4) the mixed solution was mixed with a commercial sponge and then transferred into a hydrothermal reactor for a hydrothermal reaction at 180° C. for 2 days;

[0072] (5) After the crystallization is completed, the reactor is taken out and rapidly quenched with running water, and the precipitate is separated by filtration, and then centrifuged and washed;

[0073] (6) The product is dried in a forced air drying oven at 70°C for 24 hours, and the crystallized product is calcined. The temperature is rapidly raised from room temperature to 550°C in flowing air and kept at this temperature for 6 hours, thereby obtaining a multi-level pore MFI type ZSM-5 zeolite molecular sieve loaded with metallic palladium in situ.

[0074] The XRD spectrum of the obtained in-situ loaded metal multi-level pore MFI type ZSM-5 zeolite molecular sieve is as follows: Figure 3 As shown, from Figure 3 It can be seen that the XRD spectrum of the in-situ metal-loaded multi-level pore MFI type ZSM-5 zeolite molecular sieve prepared in the embodiment of the present invention is completely consistent with the standard MFI spectrum and contains characteristic peaks, indicating that the zeolite synthesized in the embodiment of the present invention is an in-situ metal-loaded multi-level pore MFI type ZSM-5 zeolite molecular sieve; the SEM photo of the obtained in-situ metal-loaded multi-level pore MFI type ZSM-5 zeolite molecular sieve is shown in FIG. Figure 4 As shown, it can be seen from the SEM photo that the structure of the in-situ metal-loaded multi-level porous MFI type ZSM-5 zeolite molecular sieve prepared in the embodiment of the present invention is indeed ellipsoidal.

[0075] Example 6

[0076] A method for preparing a multi-level porous MFI type ZSM-5 zeolite molecular sieve material with in-situ metal loading comprises the following steps:

[0077] (1) Add NaOH solid and NaAlO2 to 11.67 g of deionized water, turn on the magnetic stirrer, set the speed to 500 rpm until a clear solution is obtained;

[0078] (2) HS-40 is then added to the clear solution obtained in the previous step, with the silicon source silicic acid being added in an amount such that the molar ratio of silicon element to aluminum element is 50:1. After the silicon source is added dropwise, it can be observed that the clear solution in the beaker gradually becomes turbid, accompanied by a significant increase in the viscosity of the system;

[0079] (3) After adding the silicic acid, add TPABR and H3BO3, wherein the molar ratio of boron ion to silicon element is 0.15:1, and the molar ratio of TPABR to silicon element is 0.15:1, and then seal the plastic beaker with wax film, continue stirring, and stir at room temperature for 3 hours; after three hours, add 1.8 ml of the prepared ethylenediamine metal complex solution;

[0080] (4) the mixed solution was mixed with a commercial sponge and then transferred into a hydrothermal reactor for a hydrothermal reaction at 180° C. for 2 days;

[0081] (5) After the crystallization is completed, the reactor is taken out and rapidly quenched with running water, the precipitate is separated by filtration, and then centrifuged and washed;

[0082] (6) The product is dried in a forced air drying oven at 70°C for 24 hours, and the crystallized product is calcined. The temperature is rapidly raised from room temperature to 550°C in flowing air and kept at this temperature for 6 hours, thereby obtaining a multi-level pore MFI type ZSM-5 zeolite molecular sieve loaded with metallic palladium in situ.

[0083] The XRD spectrum of the obtained in-situ loaded metal multi-level pore MFI type ZSM-5 zeolite molecular sieve is as follows: Figure 3 As shown, from Figure 3 It can be seen that the XRD spectrum of the in-situ metal-loaded multi-level pore MFI type ZSM-5 zeolite molecular sieve prepared in the embodiment of the present invention is completely consistent with the standard MFI spectrum and contains characteristic peaks, indicating that the zeolite synthesized in the embodiment of the present invention is an in-situ metal-loaded multi-level pore MFI type ZSM-5 zeolite molecular sieve; the SEM photo of the obtained in-situ metal-loaded multi-level pore MFI type ZSM-5 zeolite molecular sieve is shown in FIG. Figure 4 As shown, it can be seen from the SEM photo that the structure of the in-situ metal-loaded multi-level porous MFI type ZSM-5 zeolite molecular sieve prepared in the embodiment of the present invention is indeed ellipsoidal.

[0084] Example 7

[0085] A method for preparing a multi-level porous MFI type ZSM-5 zeolite molecular sieve material with in-situ metal loading comprises the following steps:

[0086] (1) Add NaOH solid and NaAlO2 to 373.44 g of deionized water, turn on the stirrer and set the speed to 500 rpm until a clear solution is obtained;

[0087] (2) HS-40 is then added to the clear solution obtained in the previous step, using silicic acid as a silicon source, in an amount such that the molar ratio of silicon to aluminum is 150:1. After the silicon source is added dropwise, it can be observed that the clear solution in the beaker gradually becomes turbid, accompanied by a significant increase in the viscosity of the system.

[0088] (3) After adding the silicic acid, TPABR and H3BO3 were added, wherein the molar ratio of boron ion to silicon element was 0.05:1, and the molar ratio of TPABR to silicon element was 0.15:1. The plastic beaker was then sealed with a wax film and stirred continuously for 3 hours at room temperature. After 3 hours, 57.6 ml of the prepared ethylenediamine metal complex solution was added;

[0089] (4) mixing the above mixed solution with the commercial sponge and transferring it into a hydrothermal reactor at a hydrothermal reaction temperature of 180° C. for 4-7 days;

[0090] (5) After the crystallization is completed, the reactor is taken out and rapidly quenched with running water, the precipitate is separated by filtration, and then centrifuged and washed;

[0091] (6) The product is dried in a forced air drying oven at 70°C for 48 hours, and the crystallized product is calcined. The temperature is rapidly raised from room temperature to 550°C in flowing air and kept at this temperature for 6 hours, thereby obtaining a multi-level pore MFI type ZSM-5 zeolite molecular sieve loaded with metallic palladium in situ.

[0092] The XRD spectrum of the in-situ metal-loaded multi-level pore MFI type ZSM-5 zeolite molecular sieve obtained in this amplified experiment is shown in Figure 5 As shown, from Figure 5 It can be seen that the XRD spectrum of the in-situ metal-loaded multi-level pore MFI type ZSM-5 zeolite molecular sieve prepared in the embodiment of the present invention is completely consistent with the standard MFI spectrum and contains characteristic peaks, indicating that the zeolite synthesized in the embodiment of the present invention is an in-situ metal-loaded multi-level pore MFI type ZSM-5 zeolite molecular sieve; the SEM photo of the obtained in-situ metal-loaded multi-level pore MFI type ZSM-5 zeolite molecular sieve is shown in FIG. Figure 6 As shown, it can be seen from the SEM photograph that the structure of the in-situ metal-loaded multi-level porous MFI type ZSM-5 zeolite molecular sieve prepared in the embodiment of the present invention is indeed spherical or ellipsoidal.

[0093] It can be understood that the above specific description of the present invention is only used to illustrate the present invention and is not limited to the technical solutions described in the embodiments of the present invention. Those skilled in the art should understand that the present invention can still be modified or replaced by equivalents to achieve the same technical effects; as long as the use requirements are met, they are within the protection scope of the present invention.

Claims

1. A method for preparing a multi-level porous MFI type ZSM-5 zeolite molecular sieve material with in-situ metal loading, characterized in that: The steps of this method are as follows:

1. Add trivalent aluminum source and hydroxide ion source into deionized water and stir to obtain a clear solution; 2. adding a tetravalent silicon source to the above clarified solution and stirring, then adding a molecular sieve template and a boron source and stirring, and then adding a metal complex solution to obtain a mixed solution; 3. Mixing the above mixed solution with a commercial sponge in a hydrothermal reactor to crystallize through a hydrothermal reaction; 4. After the crystallization is completed, the mixture in the reaction kettle is quenched, filtered, centrifuged, washed, and dried to obtain a crystallized product; 5. calcining the above crystallized product to obtain a multi-level porous MFI type ZSM-5 zeolite molecular sieve material loaded with metal in situ; Among them, the molar ratio of silicon element in the tetravalent silicon source to aluminum element in the trivalent aluminum source is 150-20:1; the molar ratio of boron ions in the boron source to silicon element in the tetravalent silicon source is 0.05-0.2:1; the molar ratio of tetrapropylammonium bromide in the molecular sieve template solution to silicon element in the tetravalent silicon source is 0.1-0.2:

1.

2. The method for preparing the in-situ metal-loaded multi-level pore MFI type ZSM-5 zeolite molecular sieve material according to claim 1, characterized in that: The tetravalent silicon source is one or more of white carbon black, silica sol, and tetraethyl orthosilicate; the trivalent aluminum source is one or more of sodium aluminate, aluminum hydroxide, aluminum nitrate, and aluminum sulfate; the hydroxide ion source is sodium hydroxide or potassium hydroxide; and the boron source is one or more of boric acid and borates.

3. The method for preparing the in-situ metal-loaded multi-level pore MFI type ZSM-5 zeolite molecular sieve material according to claim 2, characterized in that: The tetravalent silicon source is silica sol, the trivalent aluminum source is one or more of sodium aluminate and aluminum hydroxide, and the boron source is boric acid.

4. The method for preparing the in-situ metal-loaded multi-level pore MFI type ZSM-5 zeolite molecular sieve material according to claim 1, characterized in that: The mass fraction of tetrapropylammonium bromide in the molecular sieve template solution is 98%.

5. The method for preparing the in-situ metal-loaded multi-level pore MFI type ZSM-5 zeolite molecular sieve material according to claim 1, characterized in that: The reaction temperature of the hydrothermal reaction in step 3 is 135° C. to 200° C., and the hydrothermal reaction time is 48 to 168 hours.

6. The method for preparing the in-situ metal-loaded multi-level pore MFI type ZSM-5 zeolite molecular sieve material according to claim 5, characterized in that: The reaction temperature of the hydrothermal reaction in step 3 is 150° C. to 180° C., and the hydrothermal reaction time is 72 hours.

7. The method for preparing the in-situ metal-loaded multi-level pore MFI type ZSM-5 zeolite molecular sieve material according to claim 1, characterized in that: The crystallized product in step 4 is dried in a forced air drying oven at a drying temperature of 50° C. to 100° C. for 10 to 48 hours.

8. The method for preparing the in-situ metal-loaded multi-level pore MFI type ZSM-5 zeolite molecular sieve material according to claim 7, characterized in that: The crystallized product in step 4 is dried in a forced air drying oven at a drying temperature of 60° C. to 90° C. for 12 to 40 hours.

9. The method for preparing the in-situ metal-loaded multi-level pore MFI type ZSM-5 zeolite molecular sieve material according to claim 1, characterized in that: The calcination of the crystallized product in step 5 is to raise the temperature of the crystallized product from room temperature to 500-550° C. in flowing air and keep the temperature for 5-6 hours.

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