A mordenite and a method for producing the same

Abstract

The application discloses a mordenite and a preparation method thereof. The mordenite is of a mordenite structure and is a hollow-structure crystal with a single crystal particle and a hollow center. The preparation method comprises the following steps: (1) preparing a pretreated mordenite; (2) uniformly mixing the pretreated mordenite, an aluminum-containing compound, an alkali source, a silicon-containing compound, ethylenediaminetetraacetic acid and water and performing a reaction, and then washing, separating and drying a product obtained in the reaction to obtain a mordenite precursor; and (3) treating the mordenite precursor under a calcination condition to obtain a hollow mordenite. The preparation method is simple in a synthesis process and solves a technical problem that a hollow mordenite cannot be synthesized by using an existing synthesis method of a hollow mordenite.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of inorganic zeolite material synthesis, and relates to a mordenite and a preparation method thereof, in particular to a hollow mordenite and a preparation method thereof. BACKGROUND

[0002] Mordenite was first synthesized by Barrer as early as in the 1940s. Mordenite has excellent heat resistance and acid resistance due to its high silicon-aluminum ratio, and is widely used as an adsorbent for separating gas or liquid mixture and a catalyst for petroleum and fine chemical industry, and is mainly used in catalytic cracking, hydrocracking, hydroisomerization of paraffins and other oil refining processes.

[0003] CN106517239A discloses a pillared layered mordenite and a preparation method thereof. A dynamic hydrothermal synthesis method is used to synthesize a swellable layered mordenite, then the obtained swellable layered mordenite is swelled with cetyl polyoxyethylene hexadecyl bromide, and then the swelled layered mordenite is reacted with tetraethyl orthosilicate to obtain the pillared layered mordenite.

[0004] CN102190316A discloses a synthesis method of mesoporous mordenite. A silicon source, an aluminum source, an organic amine structure directing agent SDA, a high molecular mesoporous template agent R and water are mixed, the silicon source, the aluminum source, the organic amine structure directing agent SDA and the water in the mixture are mixed, the mixture is crystallized at 100-200℃ for 1-10 days to obtain a crystalline product, and the crystalline product is washed, dried and calcined to obtain the mesoporous mordenite. The high molecular mesoporous template agent is selected from starch, dextrin, cellulose, polyethylene glycol, polyvinyl alcohol, polyether, polyvinyl formal or polyvinyl butyral.

[0005] CN115536040A discloses a nano-leaf-shaped aluminum-rich mordenite molecular sieve, a synthesis method and an application thereof. The preparation steps are as follows: an aluminum source is added to a NaOH solution to obtain solution A; then a template agent, a silicon source, an aluminum-rich agent and a crystal growth inhibitor are sequentially added to solution A to obtain a uniform sol B by stirring; finally, the sol B is stirred to a dry gel state, water is added, and then the mixture is transferred to a reaction kettle to form a uniform and stable gel under high-temperature oscillation; after washing, filtering, drying, calcining, ammonia exchange and calcining, a nano-leaf-shaped aluminum-rich MOR molecular sieve with a lamella thickness of 10-100nm is obtained.

[0006] At present, the zeolite molecular sieve material with a hollow structure is a kind of special functional material. The research on related materials has become a research hotspot in the field of chemistry and new materials. The hollow zeolite molecular sieve has a multi-level structure and large specific surface area and other unique physical and chemical properties, and shows a broad application prospect in shape-selective adsorbents, catalysts, drug sustained-release agents and micro-reactors, and has attracted more and more attention.

[0007] At present, there is no industrial production method of hollow structure mordenite in the reports disclosed by the prior art, so it is of great significance to develop a synthesis method of hollow structure mordenite. SUMMARY

[0008] The application provides a mordenite and a preparation method thereof, and provides a mordenite with a hollow structure which is completely different from the structure of the existing mordenite, and the preparation method has a simple synthesis process, and solves the technical problem that the hollow mordenite cannot be synthesized by using the existing synthesis method of hollow zeolite.

[0009] Based on the above, the technical scheme of the application mainly includes the following aspects:

[0010] The first aspect of the application provides a mordenite, wherein the zeolite has a mordenite structure, and is characterized by a single crystal particle with a hollow structure under transmission electron microscopy, and the center of the crystal is in a hollow state.

[0011] Preferably, in the above mordenite, the particle diameter of the crystal of the mordenite is 90-1000 nm, and preferably 100-900 nm.

[0012] Preferably, in the above mordenite, the shell thickness of the crystal particle of the mordenite is 25-360 nm, and preferably 30-300 nm.

[0013] Preferably, in the above mordenite, the specific surface area of the mordenite is 270-590 m 2 / g, and preferably 300-560 m 2 / g.

[0014] Preferably, in the above mordenite, the pore volume of the mordenite is 0.1-0.3 cm 3 / g.

[0015] Preferably, in the above mordenite, the acid amount of the mordenite is 0.05-0.24 mmol / g.

[0016] Preferably, in the above mordenite, the silicon-aluminum ratio of the mordenite is 9-50 in terms of oxide, and preferably 10-45.

[0017] The second aspect of the application provides a preparation method of a mordenite, and the preparation method comprises the following steps:

[0018] (1) under pretreatment conditions, the mordenite is contacted with ammonia-containing gas for pretreatment, and after the pretreatment is completed, the pretreated mordenite is obtained through water washing, separation and drying;

[0019] (2) under reaction conditions, the pretreated mordenite, an aluminum-containing compound, an alkali source, a silicon-containing compound, ethylenediaminetetraacetic acid and water are uniformly mixed and reacted, and the product obtained through the reaction is subjected to water washing, separation and drying to obtain a zeolite precursor;

[0020] (3) the zeolite precursor is treated under calcination conditions to obtain the hollow mordenite.

[0021] The third aspect of the present application provides a preparation method of the mordenite, and the preparation method comprises the following steps:

[0022] Step (1): synthesizing the zeolite precursor, and the synthesizing step comprises:

[0023] (1) under pretreatment conditions, the mordenite is contacted with ammonia-containing gas for pretreatment, and after the pretreatment is completed, the pretreated mordenite is obtained through water washing, separation and drying;

[0024] (2) under reaction conditions, the pretreated mordenite, an aluminum-containing compound, an alkali source, a silicon-containing compound, ethylenediaminetetraacetic acid and water are uniformly mixed and reacted, and the product obtained through the reaction is subjected to water washing, separation and drying to obtain a zeolite precursor;

[0025] Step (2): under ammonium exchange conditions, the obtained zeolite precursor is subjected to ammonium exchange treatment, and then the hydrogen-type hollow mordenite is obtained through water washing, separation, drying and calcination.

[0026] Preferably, in the preparation method of the mordenite, the mordenite in step (1) is an MTW structure zeolite, which can be selected from commercially available products in the art or obtained by using an existing synthesis method. More specifically, the Y zeolite has the following properties: the particle diameter of the crystal is 90-1000 nm; the specific surface area is 300-600 m 2 / g, and the pore volume is 0.09-0.31 cm 3 / g.

[0027] Preferably, in the preparation method of the mordenite, the pretreatment in step (1) is a gas-solid two-phase reaction between the mordenite and the ammonia-containing gas, and the mordenite is pretreated by being contacted with the ammonia-containing gas. The specific reaction process is as follows: a support is arranged in a reactor, the mordenite is placed on the support, and ammonia water and water are added to the lower part of the support; the mordenite and the ammonia water do not directly contact each other, and further, the mass ratio of the ammonia water, the mordenite and the water is 12-28:8-25:100, preferably 15-25:10-20:100; the ammonia water is industrial ammonia water, and is a 25%-28% ammonia aqueous solution.

[0028] Preferably, in the preparation method of the mordenite, the pretreatment in step (1) is a gas-solid two-phase reaction between the mordenite and the ammonia-containing gas, and the mordenite is pretreated by being contacted with the ammonia-containing gas. The specific reaction process is as follows: a support is arranged in a reactor, the mordenite is placed on the support, and ammonia water and water are added to the lower part of the support; the mordenite and the ammonia water do not directly contact each other, and further, the mass ratio of the ammonia water, the mordenite and the water is 12-28:8-25:100, preferably 15-25:10-20:100; the ammonia water is industrial ammonia water, and is a 25%-28% ammonia aqueous solution.

[0029] Preferably, in the preparation method of the mordenite, the pretreatment in step (1) is a gas-solid two-phase reaction between the mordenite and the ammonia-containing gas, and the mordenite is pretreated by being contacted with the ammonia-containing gas. The specific reaction process is as follows: a support is arranged in a reactor, the mordenite is placed on the support, and ammonia water and water are added to the lower part of the support; the mordenite and the ammonia water do not directly contact each other, and further, the mass ratio of the ammonia water, the mordenite and the water is 12-28:8-25:100, preferably 15-25:10-20:100; the ammonia water is industrial ammonia water, and is a 25%-28% ammonia aqueous solution.

[0030] Preferably, in the preparation method of the mordenite, the alkali source in step (2) is an inorganic alkali, and specifically can be one or more of sodium hydroxide, potassium hydroxide and lithium hydroxide.

[0031] Preferably, in the preparation method of the mordenite, the aluminum-containing compound in step (2) is an aluminum-containing inorganic salt, and the acid radical ion of the aluminum-containing inorganic salt can be one or more of sulfate, metaborate, nitrate and chloride. Specifically, the aluminum-containing compound is selected from one or more of sodium aluminate, aluminum sulfate, aluminum chloride and aluminum nitrate.

[0032] Preferably, in the preparation method of the mordenite, the silicon-containing compound in step (2) is one or more of white carbon black, silica gel and silica sol.

[0033] Preferably, in the preparation method of the mordenite, the mass ratio of the alkali source, the aluminum-containing compound, the silicon-containing compound, the pretreated mordenite, the ethylenediaminetetraacetic acid and the water in step (2) is 0.8-2.5:0.8-2.1:2.5-6:8-25:0.8-3:100, preferably 1-2:1-2:2-4:10-20:1-2.5:100.

[0034] Preferably, in the preparation method of the mordenite, the reaction conditions of step (2) are as follows: the reaction temperature is 70-150°C, preferably 80-120°C, and the reaction time is 19-32h, preferably 20-30h.

[0035] Preferably, in the preparation method of the mordenite, the drying conditions of step (2) are as follows: the drying temperature is 80-150°C, and the drying time is 1-20h.

[0036] Preferably, in the preparation method of the mordenite, the ammonium treatment of step (2) can be any of the existing ammonium exchange methods in the art; the ammonium exchange treatment is performed at least once, preferably 3-5 times.

[0037] Preferably, in the preparation method of the mordenite, the ammonium exchange treatment of step (2) is ion exchange treatment of the zeolite precursor obtained after step (2), ammonium salt and water, and the mass ratio of the zeolite precursor obtained after step (2), ammonium salt and water is 8-25:8-25:100, preferably 10-20:10-20:100. The ammonium salt can be one or more of ammonium nitrate, ammonium chloride and ammonium sulfate, preferably ammonium nitrate.

[0038] Preferably, in the preparation method of the mordenite, the ammonium exchange conditions of step (2) are as follows: the ion exchange temperature is 70-100°C, preferably 80-90°C, and the ion exchange time is 1-5h, preferably 2-4h.

[0039] Preferably, in the preparation method of the mordenite, the water washing and separation of step (2) can be selected from the existing operation methods in the art. In the present application, the water washing is generally washing with deionized water until the filtrate is neutral, which can be washed several times, usually needs to be washed multiple times, such as 1-10 times. The separation is liquid-solid two-phase separation of the water-washed product, which can be any of the methods capable of realizing liquid-solid two-phase separation, such as filtration and centrifugal separation.

[0040] Preferably, in the preparation method of the mordenite, the drying conditions of step (2) are as follows: the drying temperature is 80-150°C, and the drying time is 1-20h.

[0041] Preferably, in the preparation method of the mordenite, the calcination of step (2) is performed in the presence of an oxygen-containing gas, and the oxygen content of the oxygen-containing gas is 10-100%. The oxygen-containing gas can be air, oxygen, or a mixture of oxygen and inert gas, and the inert gas is nitrogen and / or inert gas. The calcination conditions are as follows: the calcination temperature is 400-600°C, and the high-temperature calcination treatment is performed for 1-10h.

[0042] The third aspect of the present application provides a mordenite obtained by the preparation method, the mordenite has a hollow structure, and the material can be used as a carrier of drug molecules, an adsorbent or a catalytic material.

[0043] Based on the above, the technical effects of the mordenite and the preparation method thereof in the technical scheme of the present application are as follows:

[0044] In the technical scheme, the mordenite is first pretreated, in the pretreatment process, the silicon and aluminum elements in the mordenite structure are rearranged under the action of the ammonia-containing gas, in the rearrangement process, the aluminum elements may migrate to the outside of the mordenite crystal, forming a gradient distribution of the aluminum elements inside and outside the mordenite crystal, and it is analyzed that this gradient distribution promotes the formation of the hollow structure, and under the action of the ammonia gas, the crystal still maintains a relatively complete structure.

[0045] In the technical scheme, the reaction in step (2) is different from the existing hydrothermal synthesis reaction, in the reaction process, the inorganic base, the silicon-containing compound, the aluminum-containing compound and the ethylenediaminetetraacetic acid react with the mordenite, the aluminum elements enter the outside of the mordenite crystal, and the inside of the mordenite crystal is dissolved, thereby forming a hollow structure. In this process, the silicon-containing compound basically does not enter the framework of the mordenite crystal, and it is analyzed that it only plays a role in stabilizing the system. However, in the absence of the silicon-containing compound, the mordenite cannot be effectively converted into a hollow structure. The ethylenediaminetetraacetic acid can stabilize the crystal structure and avoid the collapse of the crystal structure. Moreover, the ratio of the materials in the raw material system in the present scheme is not within the effective ratio range of the existing synthesis of mordenite.

[0046] In combination with the above analysis, the present application provides a novel hollow structure mordenite and a preparation method thereof, and solves the problem that the existing synthesis method of the hollow structure mordenite cannot directly synthesize the hollow mordenite. The existing synthesis method of the hollow mordenite cannot be directly applied to the preparation of the hollow mordenite, because different types of mordenites have different crystal structures, and thus the physical and chemical properties are also quite different. As we all know, the synthesis method cannot be completely used for different types of mordenites, and different types of hollow mordenites cannot be obtained by directly replacing the raw materials. BRIEF DESCRIPTION OF DRAWINGS

[0047] Figure 1 The transmission electron microscope photo of the mordenite sample obtained in Example 1 is shown.

[0048] Figure 2 The transmission electron microscope photo of the mordenite sample obtained in Comparative Example 1 is shown.

[0049] Figure 3 The XRD spectrum of the mordenite sample obtained in Example 1 was obtained.

[0050] Figure 4 The XRD spectrum of the mordenite sample obtained in Comparative Example 1 was obtained. DETAILED DESCRIPTION

[0051] The technical solutions and effects of the present application are further illustrated below in combination with examples, but are not limited to the following examples.

[0052] In the present application, the pore structure of the zeolite material is characterized by N2 adsorption-desorption, which is tested by a physical adsorption instrument of Micromeritics Company, USA. Before testing, the sample is treated in vacuum at 300℃ for more than 4h. The specific surface area, pore size and other parameters are calculated according to BET and BJH formulas.

[0053] In the present application, the phase structure and crystallinity of the zeolite material are characterized by X-ray diffraction, which is tested by a D / max2500 X-ray diffractometer of Rigaku, Japan. The Cu target, Kα radiation source, graphite monochromator, tube voltage 40kV, tube current 80mA, scanning range 5°-40°, step size 0.1°, scanning speed 1° / min.

[0054] In the present application, the acid amount of the zeolite material is measured by ammonia temperature programmed desorption, which is tested by an AutoChem II 2920 chemical adsorption instrument of Micromeritics Company, USA. First, the temperature is raised to 550℃ at a rate of 10℃ / min under the protection of helium and kept for 1h; then, the temperature is lowered to room temperature (25℃) at a rate of 10℃ / min, ammonia is replaced and adsorbed for 1h; then, helium is replaced and the temperature is raised to 600℃ at a rate of 10℃ / min.

[0055] In the present application, the crystal morphology of the zeolite material is characterized by transmission electron microscopy, which is tested by a high-resolution transmission electron microscope of JEOL Company, Japan. The instrument model is JEM-2200FS field emission ultra-high-resolution transmission electron microscope, the acceleration voltage is 200KV, and the point resolution is 0.19nm.

[0056] In the present application, all the chemical reagents used are analytical pure chemical reagents, which can be obtained by purchasing commercially available goods.

[0057] In the present application, a support is arranged in the reaction kettle during the preparation of the pretreated mordenite.

[0058] Example 1

[0059] Put the mordenite into the upper part of the support of the reaction kettle, ammonia and water into the lower part of the support of the reaction kettle, wherein the weight ratio of mordenite, ammonia and water is zeolite, ammonia, water mass ratio = 15:18:100, then the reaction kettle is closed for pretreatment, the pretreatment temperature is 400℃, the pretreatment time is 8h; then after water washing, filtering and drying, the pretreated mordenite is obtained, the drying temperature is 120℃, and the drying time is 3h. Mix sodium hydroxide, aluminum nitrate, white carbon black, pretreated mordenite, ethylenediaminetetraacetic acid and deionized water uniformly, then put them into a closed reaction kettle and react at 100℃ for 25h, after the reaction is completed, wash with water, filter multiple times, and dry the obtained solid phase material at 120℃ for 10h to obtain a zeolite precursor; wherein the mass ratio of sodium hydroxide, aluminum nitrate, white carbon black, pretreated mordenite, ethylenediaminetetraacetic acid and deionized water is 1.3:1.2:3.3:17:1.2:100. Then mix the materials uniformly according to the mass ratio of ammonium nitrate, zeolite precursor and water 16:15:100, treat at 85℃ for 3h, and cycle for 3 times; after the end, further wash with water, filter multiple times, then dry at 120℃ for 10h, and finally calcine at 500℃ for 10h in the presence of air, and the obtained sample is numbered as C1.

[0060] Example 2

[0061] Put the mordenite into the upper part of the support of the reaction kettle, ammonia and water into the lower part of the support of the reaction kettle, wherein the weight ratio of mordenite, ammonia and water is zeolite, ammonia, water mass ratio = 15:18:100, then the reaction kettle is closed for pretreatment, the pretreatment temperature is 400℃, the pretreatment time is 8h; then after water washing, filtering and drying, the pretreated mordenite is obtained, the drying temperature is 120℃, and the drying time is 3h. Mix sodium hydroxide, aluminum nitrate, white carbon black, pretreated mordenite, ethylenediaminetetraacetic acid and deionized water uniformly, then put them into a closed reaction kettle and react at 100℃ for 25h, after the reaction is completed, wash with water, filter multiple times, and dry the obtained solid phase material at 120℃ for 10h to obtain a zeolite precursor; wherein the mass ratio of sodium hydroxide, aluminum nitrate, white carbon black, pretreated mordenite, ethylenediaminetetraacetic acid and deionized water is 1.3:1.2:3.3:17:1.2:100. Then mix the materials uniformly according to the mass ratio of ammonium nitrate, zeolite precursor and water 16:15:100, treat at 85℃ for 3h, and cycle for 3 times; after the end, further wash with water, filter multiple times, then dry at 120℃ for 10h, and finally calcine at 500℃ for 10h in the presence of air, and the obtained sample is numbered as C1.

[0062] Example 3

[0063] Put the mordenite into the upper part of the support of the reaction kettle, ammonia and water into the lower part of the support of the reaction kettle, wherein the weight ratio of mordenite, ammonia and water is zeolite, ammonia, water mass ratio = 20:25:100, then the reaction kettle is closed for pretreatment, the pretreatment temperature is 850℃, the pretreatment time is 5h; then after water washing, filtering and drying, the pretreated mordenite is obtained, the drying temperature is 120℃, and the drying time is 3h. Mix sodium hydroxide, aluminum nitrate, white carbon black, pretreated mordenite, ethylenediaminetetraacetic acid and deionized water uniformly, then put them into a closed reaction kettle and react at 120℃ for 30h, after the reaction is completed, wash with water, filter multiple times, and dry the obtained solid phase material at 120℃ for 10h to obtain a zeolite precursor; wherein the mass ratio of sodium hydroxide, aluminum nitrate, white carbon black, pretreated mordenite, ethylenediaminetetraacetic acid and deionized water is 2:2:4:20:2.5:100, then mix the materials uniformly according to the mass ratio of ammonium nitrate, zeolite precursor and water is 20:20:100, treat at 80℃ for 4h, and cycle for 3 times; after the end, further wash with water, filter multiple times, then dry at 120℃ for 10h, and finally calcine at 500℃ for 10h in the presence of air, the obtained sample is numbered as C3.

[0064] Example 4

[0065] Put the mordenite into the upper part of the support of the reaction kettle, ammonia and water into the lower part of the support of the reaction kettle, wherein the weight ratio of mordenite, ammonia and water is zeolite, ammonia, water mass ratio = 20:25:100, then the reaction kettle is closed for pretreatment, the pretreatment temperature is 850℃, the pretreatment time is 5h; then after water washing, filtering and drying, the pretreated mordenite is obtained, the drying temperature is 120℃, and the drying time is 3h. Mix sodium hydroxide, aluminum nitrate, white carbon black, pretreated mordenite, ethylenediaminetetraacetic acid and deionized water uniformly, then put them into a closed reaction kettle and react at 120℃ for 30h, after the reaction is completed, wash with water, filter multiple times, and dry the obtained solid phase material at 120℃ for 10h to obtain a zeolite precursor; wherein the mass ratio of sodium hydroxide, aluminum nitrate, white carbon black, pretreated mordenite, ethylenediaminetetraacetic acid and deionized water is 2:2:4:20:2.5:100, then mix the materials uniformly according to the mass ratio of ammonium nitrate, zeolite precursor and water is 20:20:100, treat at 80℃ for 4h, and cycle for 3 times; after the end, further wash with water, filter multiple times, then dry at 120℃ for 10h, and finally calcine at 500℃ for 10h in the presence of air, the obtained sample is numbered as C3.

[0066] Example 5

[0067] Put the mordenite into the upper part of the reactor, ammonia and water into the lower part of the reactor, wherein the weight ratio of mordenite, ammonia and water is mordenite, ammonia, water mass ratio = 11.5:23:100, then seal the reactor for pretreatment, the pretreatment temperature is 730℃, the pretreatment time is 7h; then after water washing, filtering and drying, the pretreated mordenite is obtained, the drying temperature is 120℃, and the drying time is 2h. Mix sodium hydroxide, aluminum sulfate, silica gel, pretreated mordenite, ethylenediaminetetraacetic acid and deionized water uniformly, then load into a sealed reactor and react at 90℃ for 25h, after the reaction is completed, the solid phase material obtained is washed with water, filtered multiple times, and then dried at 120℃ for 10h to obtain a zeolite precursor; wherein the mass ratio of sodium hydroxide, aluminum sulfate, silica gel, pretreated mordenite, ethylenediaminetetraacetic acid and deionized water is 1.5:1.3:3.4:18:1.3:100, then the material is mixed uniformly according to the mass ratio of ammonium nitrate, zeolite precursor and water is 16.6:12:100, treated at 88℃ for 3h, and the cycle treatment is 3 times; after the end, further washed with water, filtered multiple times, then dried at 120℃ for 10h, and finally calcined at 500℃ for 10h in the presence of air, the obtained sample is numbered as C5.

[0068] Comparative Example 1

[0069] Mix sodium hydroxide, aluminum nitrate, white carbon black, pretreated mordenite, ethylenediaminetetraacetic acid and deionized water uniformly, then load into a sealed reactor and react at 100℃ for 25h, after the reaction is completed, the solid phase material obtained is washed with water, filtered multiple times, and then dried at 120℃ for 10h to obtain a zeolite precursor; wherein the mass ratio of sodium hydroxide, aluminum nitrate, white carbon black, pretreated mordenite, ethylenediaminetetraacetic acid and deionized water is 1.3:1.2:3.3:17:1.2:100. Then mix the material uniformly according to the mass ratio of ammonium nitrate, zeolite precursor and water is 16:15:100, treat at 85℃ for 3h, and the cycle treatment is 3 times; after the end, further washed with water, filtered multiple times, then dried at 120℃ for 10h, and finally calcined at 500℃ for 10h in the presence of air, the obtained sample is numbered as C6.

[0070] Comparative Example 2

[0071] Put the mordenite into the upper part of the support of the reaction kettle, ammonia water and water into the lower part of the support of the reaction kettle, wherein the weight ratio of mordenite, ammonia water and water is zeolite, ammonia water, water mass ratio = 15:18:100, then the reaction kettle is closed for pretreatment, the pretreatment temperature is 400℃, the pretreatment time is 8h; then after water washing, filtering and drying, the pretreated mordenite is obtained, the drying temperature is 120℃, and the drying time is 3h. Mix sodium hydroxide, white carbon black, pretreated mordenite, ethylenediaminetetraacetic acid and deionized water uniformly, then put them into a closed reaction kettle and react at 100℃ for 25h, after the reaction is completed, wash, filter multiple times, and dry the obtained solid phase material at 120℃ for 10h to obtain a zeolite precursor; wherein the mass ratio of sodium hydroxide, white carbon black, pretreated mordenite, ethylenediaminetetraacetic acid and deionized water is 1.3:3.3:17:1.2:100. Then mix the materials uniformly according to the mass ratio of ammonium nitrate, zeolite precursor and water is 16:15:100, treat at 85℃ for 3h, and cycle for 3 times; after the end, further wash, filter multiple times, then dry at 120℃ for 10h, and finally calcine at 500℃ for 10h in the presence of air, the obtained sample is numbered as C1.

[0072] Comparative Example 3

[0073] Put the mordenite into the upper part of the support of the reaction kettle, ammonia water and water into the lower part of the support of the reaction kettle, wherein the weight ratio of mordenite, ammonia water and water is zeolite, ammonia water, water mass ratio = 15:18:100, then the reaction kettle is closed for pretreatment, the pretreatment temperature is 400℃, the pretreatment time is 8h; then after water washing, filtering and drying, the pretreated mordenite is obtained, the drying temperature is 120℃, and the drying time is 3h. Mix sodium hydroxide, white carbon black, pretreated mordenite, ethylenediaminetetraacetic acid and deionized water uniformly, then put them into a closed reaction kettle and react at 100℃ for 25h, after the reaction is completed, wash, filter multiple times, and dry the obtained solid phase material at 120℃ for 10h to obtain a zeolite precursor; wherein the mass ratio of sodium hydroxide, white carbon black, pretreated mordenite, ethylenediaminetetraacetic acid and deionized water is 1.3:3.3:17:1.2:100. Then mix the materials uniformly according to the mass ratio of ammonium nitrate, zeolite precursor and water is 16:15:100, treat at 85℃ for 3h, and cycle for 3 times; after the end, further wash, filter multiple times, then dry at 120℃ for 10h, and finally calcine at 500℃ for 10h in the presence of air, the obtained sample is numbered as C1.

[0074] Comparative Example 4

[0075] Put the mordenite into the upper part of the support of the reaction kettle, ammonia and water into the lower part of the support of the reaction kettle, wherein the weight ratio of mordenite, ammonia and water is zeolite, ammonia, water mass ratio = 15: 18: 100, then the reaction kettle is closed for pretreatment, the pretreatment temperature is 400℃, the pretreatment time is 8h; then after water washing, filtering and drying, the pretreated mordenite is obtained, the drying temperature is 120℃, and the drying time is 3h. Mix sodium hydroxide, aluminum nitrate, white carbon black, pretreated mordenite, deionized water uniformly, then put into a closed reaction kettle and react at 100℃ for 25h, after the reaction is completed, wash with water, filter multiple times, and dry the obtained solid phase material at 120℃ for 10h to obtain a zeolite precursor; wherein the mass ratio of sodium hydroxide, aluminum nitrate, white carbon black, pretreated mordenite and deionized water is 1.3:1.2:3.3:17:100. Then mix the materials uniformly according to the mass ratio of ammonium nitrate, zeolite precursor and water is 16:15:100, treat at 85℃ for 3h, and cycle for 3 times; after the end, further wash with water, filter multiple times, then dry at 120℃ for 10h, finally calcine at 500℃ for 10h in the presence of air, and the obtained sample is numbered as C9.

[0076] Comparative Example 5

[0077] Put the mordenite into the upper part of the support of the reaction kettle, ammonia and water into the lower part of the support of the reaction kettle, wherein the weight ratio of mordenite, ammonia and water is zeolite, ammonia, water mass ratio = 15: 18: 100, then the reaction kettle is closed for pretreatment, the pretreatment temperature is 400℃, the pretreatment time is 8h; then after water washing, filtering and drying, the pretreated mordenite is obtained, the drying temperature is 120℃, and the drying time is 3h. Mix sodium hydroxide, aluminum nitrate, white carbon black, pretreated mordenite, deionized water uniformly, then put into a closed reaction kettle and react at 100℃ for 25h, after the reaction is completed, wash with water, filter multiple times, and dry the obtained solid phase material at 120℃ for 10h to obtain a zeolite precursor; wherein the mass ratio of sodium hydroxide, aluminum nitrate, white carbon black, pretreated mordenite and deionized water is 1.3:1.2:3.3:17:100. Then mix the materials uniformly according to the mass ratio of ammonium nitrate, zeolite precursor and water is 16:15:100, treat at 85℃ for 3h, and cycle for 3 times; after the end, further wash with water, filter multiple times, then dry at 120℃ for 10h, finally calcine at 500℃ for 10h in the presence of air, and the obtained sample is numbered as C9.

[0078] Table 1: Physical and chemical properties of samples obtained in each example and comparative example

[0079]

[0080]

[0081] Note: The sample from Example 1 is taken as the reference sample, and its crystallinity is set as 100%. The relative crystallinity of all other samples is obtained by comparison with the crystallinity of the reference sample. The original acid amount of the mordenite is 0.167 mmol / g.

Claims

1. A mordenite zeolite, wherein the zeolite has a mordenite structure and is characterized by transmission electron microscopy as a hollow crystal structure of a single crystal particle, wherein the central part of the crystal is hollow. The first preparation method of the mordenite zeolite has the following steps: (1) Under pretreatment conditions, mordenite is pretreated by contacting ammonia-containing gas. The reaction process is as follows: a support is set in the reactor, mordenite is placed on the support, and ammonia water and water are added to the lower part of the reactor support. The mass ratio of ammonia water, mordenite and water is 12-28: 8-25:

100. After treatment, the pretreated mordenite is obtained by washing, separating and drying. The pretreatment temperature is 400-900℃ and the pretreatment time is 0.5-6 hours. (2) Under the reaction conditions, pretreated mordenite, aluminum-containing compound, alkali source, silicon-containing compound, ethylenediaminetetraacetic acid, and water were mixed evenly and reacted. The product obtained from the reaction was washed with water, separated, and dried to obtain the zeolite precursor. The mass ratio of alkali source, aluminum-containing compound, silicon-containing compound, pretreated mordenite, ethylenediaminetetraacetic acid, and water was 0.8-2.5:0.8-2.1:2.5-6:8-25:0.8-3:

100. The reaction temperature was 70-150℃ and the reaction time was 19-32 h. (3) Hollow mordenite was obtained by treating the zeolite precursor under calcination conditions; The second preparation method of the mordenite zeolite has the following steps: Step (1): Synthesis of zeolite precursors. The synthesis steps include: (1) Under pretreatment conditions, mordenite is pretreated by contacting ammonia-containing gas. The reaction process is as follows: a support is set in the reactor, mordenite is placed on the support, and ammonia water and water are added to the lower part of the reactor support. The mass ratio of ammonia water, mordenite and water is 12-28: 8-25:

100. After treatment, the pretreated mordenite is obtained by washing, separating and drying. The pretreatment temperature is 400-900℃ and the pretreatment time is 0.5-6 hours. (2) Under the reaction conditions, pretreated mordenite, aluminum-containing compound, alkali source, silicon-containing compound, ethylenediaminetetraacetic acid, and water were mixed evenly and reacted. The product obtained from the reaction was washed with water, separated, and dried to obtain the zeolite precursor. The mass ratio of alkali source, aluminum-containing compound, silicon-containing compound, pretreated mordenite, ethylenediaminetetraacetic acid, and water was 0.8-2.5:0.8-2.1:2.5-6:8-25:0.8-3:

100. The reaction temperature was 70-150℃ and the reaction time was 19-32 h. Step (2): Under ammonium exchange conditions, the obtained zeolite precursor is subjected to ammonium exchange treatment, and then washed with water, separated, dried and calcined to obtain hydrogen-form hollow mordenite zeolite.

2. The mordenite according to claim 1, characterized in that: The crystal diameter of mordenite is 90–1000 nm; the shell thickness of mordenite crystal particles is 25–360 nm.

3. The mordenite according to claim 1, characterized in that: The crystal diameter of mordenite is 100–900 nm; the shell thickness of mordenite crystal particles is 30–300 nm.

4. The mordenite according to claim 1, characterized in that: The specific surface area of ​​mordenite is 270–590 m². 2 / g; the pore volume of mordenite is 0.1–0.3 cm³. 3 / g.

5. The mordenite according to claim 1, characterized in that: The specific surface area of ​​mordenite is 300–560 m². 2 / g.

6. The mordenite according to claim 1, characterized in that: The acidity of mordenite is 0.05–0.24 mmol / g.

7. The mordenite according to claim 1, characterized in that: The silica-alumina ratio of mordenite, calculated as oxides, is 9–50.

8. The mordenite according to claim 1, characterized in that: The silica-alumina ratio of mordenite, calculated as oxides, is 10–45.

9. A method for preparing the mordenite according to any one of claims 1-8, wherein the preparation method comprises the following steps: (1) Under pretreatment conditions, mordenite is pretreated by contacting ammonia-containing gas. The reaction process is as follows: a support is set in the reactor, mordenite is placed on the support, and ammonia water and water are added to the lower part of the reactor support. The mass ratio of ammonia water, mordenite and water is 12-28: 8-25:

100. After treatment, the pretreated mordenite is obtained by washing, separating and drying. The pretreatment temperature is 400-900℃ and the pretreatment time is 0.5-6 hours. (2) Under the reaction conditions, pretreated mordenite, aluminum-containing compound, alkali source, silicon-containing compound, ethylenediaminetetraacetic acid, and water were mixed evenly and reacted. The product obtained from the reaction was washed with water, separated, and dried to obtain the zeolite precursor. The mass ratio of alkali source, aluminum-containing compound, silicon-containing compound, pretreated mordenite, ethylenediaminetetraacetic acid, and water was 0.8-2.5:0.8-2.1:2.5-6:8-25:0.8-3:

100. The reaction temperature was 70-150℃ and the reaction time was 19-32 h. (3) Hollow mordenite was obtained by treating the zeolite precursor under calcination conditions.

10. A method for preparing the mordenite according to any one of claims 1-8, wherein the preparation method comprises the following steps: Step (1): Synthesis of zeolite precursors. The synthesis steps include: (1) Under pretreatment conditions, mordenite is pretreated by contacting ammonia-containing gas. The reaction process is as follows: a support is set in the reactor, mordenite is placed on the support, and ammonia water and water are added to the lower part of the reactor support. The mass ratio of ammonia water, mordenite and water is 12-28: 8-25:

100. After treatment, the pretreated mordenite is obtained by washing, separating and drying. The pretreatment temperature is 400-900℃ and the pretreatment time is 0.5-6 hours. (2) Under the reaction conditions, pretreated mordenite, aluminum-containing compound, alkali source, silicon-containing compound, ethylenediaminetetraacetic acid, and water were mixed evenly and reacted. The product obtained from the reaction was washed with water, separated, and dried to obtain the zeolite precursor. The mass ratio of alkali source, aluminum-containing compound, silicon-containing compound, pretreated mordenite, ethylenediaminetetraacetic acid, and water was 0.8-2.5:0.8-2.1:2.5-6:8-25:0.8-3:

100. The reaction temperature was 70-150℃ and the reaction time was 19-32 h. Step (2): Under ammonium exchange conditions, the obtained zeolite precursor is subjected to ammonium exchange treatment, and then washed with water, separated, dried and calcined to obtain hydrogen-form hollow mordenite zeolite.

11. The method for preparing mordenite according to claim 9 or 10, characterized in that: The mass ratio of ammonia, mordenite, and water is 15–25: 10–20:

100.

12. The method for preparing mordenite according to claim 9 or 10, characterized in that: The pretreatment conditions in step (1) are as follows: the pretreatment temperature is 450-850℃ and the pretreatment time is 1-5 hours.

13. The method for preparing mordenite according to claim 9 or 10, characterized in that: The alkali source in step (2) is an inorganic alkali, which is one or more of sodium hydroxide, potassium hydroxide, and lithium hydroxide.

14. The method for preparing mordenite according to claim 9 or 10, characterized in that: The aluminum-containing compound in step (2) is an aluminum-containing inorganic salt, and the anions of the aluminum-containing inorganic salt are one or more of sulfate, aluminate, nitrate and chloride ions.

15. The method for preparing mordenite according to claim 9 or 10, characterized in that: The aluminum-containing compound in step (2) is selected from one or more of sodium aluminate, aluminum sulfate, aluminum chloride, and aluminum nitrate.

16. The method for preparing mordenite according to claim 9 or 10, characterized in that: The silicon-containing compound in step (2) is one or more of silica, silica gel, and silica sol.

17. The method for preparing mordenite according to claim 9 or 10, characterized in that: In step (2), the mass ratio of alkali source, aluminum-containing compound, silicon-containing compound, pretreated mordenite, ethylenediaminetetraacetic acid, and water is 1-2:1-2:2-4:10-20:1-2.5:

100.

18. The method for preparing mordenite according to claim 9 or 10, characterized in that: The reaction conditions in step (2) are: reaction temperature 80-120℃, reaction time 20-30 h.

19. The method for preparing mordenite according to claim 9 or 10, characterized in that: The drying conditions in step (2) are: drying temperature of 80-150℃ and drying time of 1-20h.

20. The method for preparing mordenite according to claim 10, characterized in that: The ammonium exchange treatment in step (ii) involves mixing the zeolite precursor, ammonium salt, and water obtained after drying in step (2) for ion exchange treatment. Based on the mass ratio, the mass ratio of the zeolite precursor, ammonium salt, and water obtained after drying in step (2) is 8-25:8-25:

100. The ammonium salt is one or more of ammonium nitrate, ammonium chloride, and ammonium sulfate.

21. The method for preparing mordenite according to claim 20, characterized in that: Based on the mass ratio, the mass ratio of zeolite precursor, ammonium salt and water obtained after drying in step (2) is 10-20:10-20:100; the ammonium salt is ammonium nitrate.

22. The method for preparing mordenite according to claim 10, characterized in that: The ammonium exchange conditions in step (ii) are: ion exchange temperature of 70-100℃ and ion exchange time of 1-5 h.

23. The method for preparing mordenite according to claim 10, characterized in that: The ammonium exchange conditions in step (ii) are: ion exchange temperature of 80-90℃ and ion exchange time of 2-4 h.

24. The method for preparing mordenite according to claim 10, characterized in that: The drying conditions in step (II) are as follows: drying temperature is 80-150℃, and drying time is 1-20h.

25. The method for preparing mordenite according to claim 10, characterized in that: The calcination in step (II) is carried out in the presence of oxygen-containing gas with an oxygen volume fraction of 10-100%. The calcination conditions are as follows: the calcination temperature is 400-600℃ and the calcination treatment is 1-10h.

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