Integrated carrier-membrane zeolite membrane prepared from clay, its preparation method and application

Abstract

The present invention provides a carrier-membrane integrated molecular sieve membrane prepared from clay, its preparation method and application. The clay is prepared into a porous carrier precursor, then the clay interface on the surface of the carrier precursor is transformed into a dense molecular sieve layer, and finally a carrier-membrane integrated molecular sieve membrane with high-efficiency separation performance is obtained through high-temperature calcination. Compared with the prior art, the present invention uses inexpensive clay to replace traditional chemical pure substances as the carrier raw material, which not only reduces the preparation cost of the carrier, but also can significantly reduce the calcination temperature of the carrier; by utilizing the property that clay is easily transformed into molecular sieve, the dense clay layer on the surface of the carrier precursor is transformed into a molecular sieve membrane, which can improve the denseness of the molecular sieve membrane; the clay is transformed into a molecular sieve membrane by a gas-phase transformation method, which can reduce the dosage of chemical reagents and the emission of pollutants, achieving the effects of energy conservation and environmental protection.

Description

Technical Field

[0001] The present invention belongs to the field of membrane separation, and particularly relates to a carrier-membrane layer integrated molecular sieve membrane prepared from clay, and a preparation method and application thereof. Background Art

[0002] Membrane separation technology has become one of the most commonly used separation technologies to address major challenges in the fields of water resources, energy, environment, etc. Membrane materials are the core of membrane separation technology and have been widely used in fields such as microfiltration, nanofiltration, and ultrafiltration. However, preparing membrane materials with separation performance for mixtures with molecular-level differences remains a recognized difficult problem.

[0003] Molecular sieve membranes have become ideal membrane materials for separating small molecule mixtures due to their uniform, molecular-level pores. After decades of exploration and research, the quality of molecular sieve membranes has been greatly improved. However, the membrane layer defects existing in molecular sieve membranes provide non-selective channels for the transport of substances, reducing the inherent separation performance of molecular sieve membranes. Therefore, it is crucial to reduce or eliminate membrane layer defects during the preparation of molecular sieve membranes.

[0004] Molecular sieve membranes are usually grown on the surface of porous carriers, and the structure, morphology, and chemical properties of the carriers have a significant impact on the quality of molecular sieve membranes. Research shows that the preparation cost of carriers accounts for more than 50% of the total cost of molecular sieve membranes.

[0005] Nevertheless, existing molecular sieve membrane preparation technologies still cannot ensure the uniform and dense growth of molecular sieve membranes on the surface of carriers, resulting in molecular sieve membranes being not only more expensive than organic membranes but also having separation performance far lower than that of organic membranes.

[0006] A patent with publication number CN 115583657 A, published on January 10, 2023, discloses a preparation method of an MFI molecular sieve membrane, including the following steps: S1, seed synthesis: forming molecular sieve seeds on a carrier by grinding or ultrasonic treatment of appropriately heated seeds; S2, preparing a mixed sol solution: dispersing fresh coagulated colloidal particles, adding them to water and adding an appropriate amount of thickener to form a mixed sol solution; S3, preparing a mixed material; S4, performing high-temperature crystallization; S5, forming to obtain an MFI molecular sieve membrane. Adding an appropriate amount of thickener makes the mixed sol solution easier to mix and the prepared mixed sol solution more suitable for crystallization. When preparing a synthesis solution by mixing molecular sieve seeds and the mixed sol solution, a pore-forming agent is added to make the pore size of the prepared MFI molecular sieve membrane more uniform. However, the membrane prepared by hydrothermal treatment after coating seeds on an existing carrier has a complex preparation method.

[0007] Therefore, there is an urgent need to adopt new carriers and new molecular sieve membrane preparation technologies to improve the separation selectivity and economic performance of molecular sieve membranes. Summary of the Invention

[0008] The object of the present invention is to provide a carrier-membrane integrated molecular sieve membrane prepared from clay and a preparation method thereof. The clay is prepared into a porous carrier precursor, then the clay interface on the surface of the carrier precursor is transformed into a dense molecular sieve layer, and finally a carrier-membrane integrated molecular sieve membrane with high-efficiency separation performance is obtained through high-temperature calcination. The carrier is prepared by using inexpensive clay, and the molecular sieve membrane is prepared by non-solvent conversion, and the preparation method is simple.

[0009] Another object of the present invention is to provide an application of the carrier-membrane integrated molecular sieve membrane prepared from clay, which is used for the separation of homogeneous systems, such as the separation of mixed gases, the separation of alcohol-water mixtures, the separation of organic isomers, etc.

[0010] The specific technical solution of the present invention is as follows:

[0011] A preparation method of a carrier-membrane integrated molecular sieve membrane prepared from clay, comprising the following steps:

[0012] 1) Mix clay, a dispersant, a pore former, a flux, a supplementary material and an activator evenly, and form them to obtain a carrier precursor;

[0013] 2) Place the carrier precursor in a crystallization kettle, seal it, and carry out crystallization synthesis;

[0014] 3) Calcinate the product of step 2) to form a carrier-membrane integrated molecular sieve membrane.

[0015] The clay described in step 1) includes but is not limited to one or more of kaolin, montmorillonite, attapulgite, illite, diatomite, sepiolite, hydromica, glauconite, chlorite;

[0016] The clay in step 1) can be pretreated, and the pretreatment includes high-temperature heat treatment, acid solution treatment and / or alkali solution treatment;

[0017] The high-temperature heat treatment in step 1) is specifically: heating the clay to 400-900 °C, calcining for 0.5 h-48 h, and the heating and cooling rate is 0.1-30 °C / min; high-temperature heat treatment in an air atmosphere.

[0018] The high-temperature heat treatment in step 1) can also be: roasting the clay after mixing it with an alkali, and the roasting conditions are: heating to 400-900 °C, roasting for 0.5 h-48 h, and the heating and cooling rate is 0.1-30 °C / min; the mixing mass ratio of the clay to the alkali is 1:0.01-30; the alkali is one or more of sodium hydroxide, potassium hydroxide, lithium hydroxide, cesium hydroxide, magnesium hydroxide or calcium hydroxide;

[0019] The acid solution treatment in step 1) is specifically as follows: adding clay into the acid solution and stirring at 30°C - 200°C for 0.5 h - 24 h; the acid solution is one or more of nitric acid, sulfuric acid, hydrochloric acid, and phosphoric acid solutions, with an acid concentration of 0.1 - 10 mol / L; the mass concentration of clay in the acid solution is 5 - 1000 mg / mL;

[0020] The alkali solution treatment in step 1) is specifically as follows: adding clay into the alkali solution and stirring at 30°C - 200°C for 0.5 h - 24 h; the alkali concentration is 0.1 - 20 mol / L; the mass concentration of clay in the alkali solution is 5 - 1000 mg / mL; the alkali solution is one or more of sodium hydroxide, potassium hydroxide, lithium hydroxide, and cesium hydroxide;

[0021] In step 1), the content of the dispersant described in step 1) accounts for 0% - 50% of the total mass of the carrier precursor; the dispersant includes, but is not limited to, one or more of water, methanol, ethanol, propanol, ethylene glycol, propylene glycol, butylene glycol, acetone, ether, tetrahydrofuran, dimethyl ether, N-methylpyrrolidone, N,N-dimethylformamide, and dimethyl sulfoxide;

[0022] In step 1), the content of the pore former described in step 1) accounts for 0% - 40% of the total mass of the carrier precursor; the pore former includes one or more of high molecular materials or inorganic materials; the high molecular materials include, but are not limited to, one or more of methyl cellulose, carboxymethyl cellulose, starch, chitosan, urea, polyvinyl chloride, polystyrene, polymethyl methacrylate, polyvinyl butyral, polystyrene, polyethylene glycol, polyethylene, polyvinyl alcohol, polyoxyethylene, and polyoxypropylene; the inorganic materials include, but are not limited to, one or more of wood chips, graphite, carbon powder, and carbon black;

[0023] In step 1), the content of the flux described in step 1) accounts for 0% - 10% of the total mass of the carrier precursor; the flux includes, but is not limited to, one or more of silicon dioxide, aluminum oxide, talcum powder, and titanium dioxide;

[0024] The supplementary material in step 1) is a silicon source, aluminum source, or phosphorus source added to ensure the silicon-aluminum ratio, phosphorus-silicon ratio, or phosphorus-aluminum ratio in the molecular sieve membrane. The silicon-aluminum ratio or phosphorus-aluminum ratio is different for different types of molecular sieves, and even for the same molecular sieve, its silicon-aluminum ratio can be adjusted as needed. The silicon source includes, but is not limited to, one or more of silicon dioxide, silica sol, silicate, and organosilicon; the aluminum source includes, but is not limited to, one or more of aluminum oxide, aluminum sol, aluminate, aluminum chloride, aluminum sulfate, boehmite, pseudo-boehmite, aluminum nitrate, aluminum phosphate, and organoaluminum; the phosphorus source includes, but is not limited to, one or more of phosphoric acid, phosphorus trioxide, phosphorus trichloride, phosphorus pentasulfide, sodium tripolyphosphate, calcium phosphate, and organophosphides;

[0025] The content of the activator described in step 1) accounts for 0%-50% of the total mass of the carrier precursor; the activator includes but is not limited to one or more of ammonia water, dimethylamine, trimethylamine, diethylamine, triethylamine, ammonium chloride, sodium chloride, ammonium iodide, ammonium fluoride, sodium fluoride, potassium fluoride, lithium fluoride, ammonium fluorosilicate, ammonium fluoroaluminate, fluoroaluminosilicate, sodium hydroxide, potassium hydroxide, lithium hydroxide, potassium carbonate, lithium carbonate, sodium carbonate, potassium bicarbonate, lithium bicarbonate, sodium bicarbonate, lithium phosphate, sodium phosphate, potassium phosphate, potassium hydrogen phosphate, lithium hydrogen phosphate, sodium hydrogen phosphate, potassium dihydrogen phosphate, lithium dihydrogen phosphate, sodium dihydrogen phosphate;

[0026] The mixing uniformity in step 1) means that the raw materials are mixed uniformly by crushing, stirring, ball milling, grinding or pugging;

[0027] The forming in step 1) includes forming by extrusion, pressing, slip casting or knife coating;

[0028] The morphology of the carrier precursor in step 1) includes flaky, single-tubular, multi-channel or hollow fiber;

[0029] In step 2), the carrier precursor is placed in a crystallization kettle. After the crystallization kettle is sealed, it is transferred to a drying oven for crystallization synthesis, so that the clay interface on the surface of the carrier precursor is transformed into a dense molecular sieve layer;

[0030] Before the carrier precursor in step 2) is placed in the crystallization kettle, seeds can be assembled first;

[0031] Before the carrier precursor in step 2) is placed in the crystallization kettle, a template agent can be assembled first;

[0032] In step 2), the crystallization kettle can contain an alkali solution. The carrier precursor is placed above the alkali solution in the crystallization kettle and does not contact the alkali solution; the alkali solution is one or more of ammonia water or an organic amine solution, and the mass content of ammonia water or the organic amine in the alkali solution is 0%-99%;

[0033] The crystallization temperature in step 2) is 60°C - 220°C, and the crystallization time is 3h - 120h;

[0034] In step 3), roasting is carried out in a muffle furnace, the roasting temperature is 300 - 1800°C, the roasting time is 0.5h - 24h, the heating and cooling rate is 0.1 - 5°C / min, and during the heating process, it can be kept warm at 200 - 500°C for 1h - 4h;

[0035] The molecular sieve membranes prepared in step 3) include but are not limited to LTA, FAU, MFI, *BEA, TON, SAPO, CHA.

[0036] Preferably, the preparation method of the LTA molecular sieve membrane is as follows:

[0037] Mix kaolin with alkali and then calcine it. Then mix it with water, pore former and activator. After molding, directly transfer it to a crystallization kettle for crystallization, and then calcine it to obtain an LTA molecular sieve membrane;

[0038] Preferably, the preparation method of the *BEA molecular sieve membrane is as follows: Mix bentonite, water, pore former and activator, and after molding, then assemble the template agent; Then place it above the alkali solution in the crystallization kettle without contacting the alkali solution, and after crystallization, calcine it.

[0039] Preferably, the preparation method of the FAU molecular sieve membrane is as follows: Pretreat sepiolite with an acid solution, then mix it with a pore former, a supplementary material and an activator, then mold it, and then assemble the seed crystals. Place it above the alkali solution in the crystallization kettle without contacting the alkali solution, and after crystallization, calcine it.

[0040] Or, preferably, the preparation method of the FAU molecular sieve membrane is as follows: Pretreat kaolin with an acid solution, then mix it with a pore former, a supplementary material and an activator, and then place it above the alkali solution in the crystallization kettle without contacting the alkali solution, and after crystallization, calcine it.

[0041] Preferably, the preparation method of the ZSM-5 molecular sieve membrane is as follows: Mix attapulgite, dispersant and activator, first assemble the template agent, then place it above the alkali solution in the crystallization kettle without contacting the alkali solution, and after crystallization, calcine it.

[0042] The carrier-membrane integrated molecular sieve membrane prepared from clay provided by the present invention is prepared by the above method.

[0043] The application of the carrier-membrane integrated molecular sieve membrane prepared from clay provided by the present invention is used for the separation of homogeneous systems, such as the separation of mixed gases, the separation of alcohol-water mixtures, the separation of organic isomers, etc. Preferably, it is used for the separation of methanol and methyl tert-butyl ether, or for the separation of water and ethanol; the separation of p-xylene and other xylenes, the separation of propanol and water, oil-water separation, battery diaphragms, and has ultra-high permeation selectivity.

[0044] The traditional molecular sieve membrane preparation process includes processes such as the preparation of the carrier, the preparation of the synthesis solution, hydrothermal crystallization and high-temperature calcination ( Figure 5 ). The whole process flow is long, the preparation process is complex, and a large amount of energy is consumed. In addition, an excessive amount of synthesis solution is required in the hydrothermal crystallization process, which is very easy to cause environmental pollution.

[0045] The present invention uses inexpensive clay to prepare a carrier-membrane integrated molecular sieve membrane, prepares a porous carrier precursor from the clay, then converts the clay interface on the surface of the carrier precursor into a dense molecular sieve layer, and finally obtains a carrier-membrane integrated molecular sieve membrane with high separation performance through high-temperature calcination ( Figure 6 ).

[0046] Compared with the prior art, the present invention uses inexpensive clay to replace traditional chemical pure substances as the carrier raw material, which not only reduces the preparation cost of the carrier, but also can significantly reduce the calcination temperature of the carrier; by utilizing the characteristic that clay is easily transformed into molecular sieve, the dense clay layer on the surface of the carrier precursor is transformed into a molecular sieve membrane, which can improve the denseness of the molecular sieve membrane; the clay is transformed into a molecular sieve membrane by a non-solvent transformation method, which can reduce the usage amount of chemical reagents and the emission amount of pollutants, achieving the effects of energy conservation and environmental protection. Description of the Drawings

[0047] Figure 1 SEM image of the LTA molecular sieve membrane obtained in Example 1;

[0048] Figure 2 SEM image of the *BEA molecular sieve membrane obtained in Example 2;

[0049] Figure 3 SEM image of the FAU molecular sieve membrane obtained in Example 3;

[0050] Figure 4 SEM image of the ZSM-5 molecular sieve membrane obtained in Example 4;

[0051] Figure 5 Schematic process flow diagram of the traditional preparation method;

[0052] Figure 6 Schematic process flow diagram of the preparation method of the invention. Detailed Embodiments

[0053] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0054] The test materials and reagents used in the following embodiments can be obtained from commercial channels without special instructions.

[0055] For those not specifying specific techniques or conditions in the embodiments, they can all be carried out according to the techniques or conditions described in the literature in this field or according to the product specifications.

[0056] Example 1

[0057] A preparation method of a carrier-membrane integrated molecular sieve membrane prepared from clay, comprising the following steps:

[0058] 1) Mix 1000 g of kaolin (a type of clay mainly containing kaolinite) with 50 g of sodium hydroxide, grind them, then calcine at 600 °C for 3 h. After cooling, wash with water, filter by suction, and clean with deionized water to obtain pretreated kaolin;

[0059] 2) Stir and mix 200 g of pretreated kaolin, 50 g of water (dispersant), 20 g of polyethylene glycol (pore former), 10 g of ammonium fluoride (activator), and 20 g of sodium hydroxide (activator) evenly for 20 min, and then extrude it into a single-tube tubular carrier precursor using an extrusion device;

[0060] 3) Transfer the tubular carrier precursor to a crystallization kettle, then seal the crystallization kettle and transfer it to a drying oven for crystallization at 100 °C for 72 h;

[0061] 4) After the crystallization kettle cools, take out the tubular carrier precursor and put it into a muffle furnace. The heating and cooling rate in the air atmosphere is 0.3 °C / min. Keep it at 200 °C for 2 h, and then heat it up to 800 °C for calcination for 12 h to obtain a carrier-membrane integrated LTA zeolite membrane.

[0062] Figure 1 This is the SEM image of the LTA zeolite membrane obtained in Example 1. As can be seen from the figure, a dense, flat, and defect-free LTA zeolite membrane is formed on the surface of the carrier.

[0063] The clay-prepared carrier-membrane integrated zeolite membrane prepared in Example 1 is used for separating water and ethanol. Specifically:

[0064] Perform pervaporation testing on the LTA zeolite membrane prepared in step 4). Fix the zeolite membrane in a separation membrane cell, and introduce a water / ethanol (10 / 90 wt%) mixture at 75 °C. The operating pressure is 0.1 MPa. The permeation flux of the LTA zeolite membrane is 8.3 kg·m -2 ·h -1 , and the water / ethanol permeation selectivity is greater than 10000.

[0065] Example 2

[0066] A preparation method of a carrier-membrane integrated zeolite membrane prepared from clay, comprising the following steps:

[0067] 1) Stir and mix 200 g of bentonite (a type of clay mainly containing montmorillonite), 50 g of water (dispersant), 20 g of polyethylene glycol (pore former), and 30 g of potassium hydroxide (activator) for 20 min, and then extrude it into a single-tube tubular carrier precursor using an extrusion device;

[0068] 2) Immerse the carrier precursor into 1 mol / L tetraethylammonium bromide (template agent) for 1 min, then slowly pull it out to obtain the carrier precursor coated with the template agent. Add 10 mL of a 30% by mass tetraethylammonium bromide solution to the crystallization kettle, then transfer the tubular carrier precursor to the crystallization kettle without contacting the solution, and then seal the crystallization kettle and transfer it to a drying oven for crystallization at 120 °C for 96 h;

[0069] 3) After the crystallization kettle cools down, take out the tubular carrier precursor and place it in a muffle furnace with a heating and cooling rate of 0.3 °C / min. Keep it at 200 °C for 2 h, then raise the temperature to 600 °C and calcine for 12 h to obtain the carrier-membrane integrated *BEA zeolite membrane.

[0070] Figure 2 This is the SEM image of the *BEA zeolite membrane obtained in Example 2. As can be seen from the figure, a dense, flat and defect-free *BEA zeolite membrane is formed on the surface of the carrier.

[0071] Example 3

[0072] A preparation method of a carrier-membrane integrated molecular sieve membrane prepared from clay, comprising the following steps:

[0073] 1) Add 10 g of sepiolite to 100 mL of 10 mol / L nitric acid solution, stir at 50 °C for 24 h, filter by suction after cooling and wash with deionized water to obtain pretreated sepiolite;

[0074] 2) Mix 2 g of pretreated sepiolite, 0.2 g of carboxymethyl cellulose (pore former), 0.5 g of silicon dioxide (additive), and 0.2 g of sodium hydroxide (activator) and stir for 20 min, then use the tabletting method to make a sheet-shaped carrier precursor;

[0075] 3) Assemble FAU zeolite seeds on the surface of the carrier precursor. Specifically, disperse FAU seeds with a particle size of 200 nm in absolute ethanol to obtain a 5 g / L FAU seed suspension, then immerse the carrier precursor into the seed suspension, impregnate for 30 s and slowly pull it out to obtain the carrier precursor assembled with FAU zeolite seeds. Add 10 mL of a 10% by mass ammonia water solution to the crystallization kettle, then transfer the sheet-shaped carrier precursor to the crystallization kettle without contacting the solution, and then seal the crystallization kettle and transfer it to a drying oven for crystallization at 140 °C for 36 h;

[0076] 4) After the crystallization kettle cools down, take out the tubular carrier precursor and place it in a muffle furnace with a heating and cooling rate of 0.3 °C / min. Keep it at 200 °C for 2 h, and then raise the temperature to 1000 °C and calcine for 12 h to obtain the carrier-membrane integrated FAU zeolite membrane.

[0077] Figure 3This is the SEM image of the FAU zeolite membrane obtained in Example 3. As can be seen from the figure, a dense, flat and defect-free FAU zeolite membrane was formed on the surface of the support.

[0078] The clay-prepared support-membrane integrated zeolite membrane prepared in Example 3 was used for separating methanol and methyl tert-butyl ether, specifically as follows:

[0079] The FAU zeolite membrane prepared in step 4) was subjected to pervaporation testing. The permeation flux of the FAU zeolite membrane was 4.1 kg·m -2 ·h -1 , and the methanol / methyl tert-butyl ether permeation selectivity was greater than 10000.

[0080] Example 4

[0081] A method for preparing a clay-prepared support-membrane integrated zeolite membrane includes the following steps:

[0082] 1) 2 g of attapulgite (a kind of clay, mainly containing attapulgite), 0.5 g of polyvinyl alcohol (dispersant), and 0.2 g of ammonium fluoride ((activator)) were mixed and ground for 30 min, and then pressed into a sheet-like support precursor using a tablet press;

[0083] 3) 0.5 mL of 0.5 mol / L tetrapropylammonium bromide (template agent) was evenly dropped onto the surface of the sheet-like support precursor to obtain a support precursor assembled with the template agent. 10 mL of 10% ammonia water by mass was added to the crystallization kettle, and then the sheet-like support precursor was transferred to the crystallization kettle without contacting the solution. Then the crystallization kettle was sealed and transferred to an oven for crystallization at 180 °C for 24 h;

[0084] 4) After the crystallization kettle cooled, the sheet-like support precursor was taken out and placed in a muffle furnace with a heating and cooling rate of 0.5 °C / min, where it was kept at 200 °C for 1 h and then heated to 500 °C and calcined for 6 h to obtain a support-membrane integrated ZSM-5 (a kind of MFI type) zeolite membrane.

[0085] Figure 4 This is the SEM image of the ZSM-5 zeolite membrane obtained in Example 4. As can be seen from the figure, a dense, flat and defect-free ZSM-5 zeolite membrane was formed on the surface of the support.

[0086] The clay-prepared support-membrane integrated zeolite membrane prepared in Example 4 was used for separating p-xylene from other xylenes, specifically as follows:

[0087] The ZSM-5 zeolite membrane prepared in step 4) was subjected to permeation performance testing. The permeation flux of the ZSM-5 zeolite membrane was 6.5 kg·m -2 ·h -1, the permeation selectivity of p-xylene relative to other xylenes (m-xylene, o-xylene) is greater than 1000.

[0088] Example 5

[0089] A preparation method of a carrier-membrane integrated molecular sieve membrane prepared from clay, comprising the following steps:

[0090] 1) Add 10 g of kaolin to 100 mL of 1 mol / L nitric acid solution, stir at 80 °C for 6 h, filter by suction after cooling, and wash with deionized water to obtain pretreated kaolin;

[0091] 2) Mix 2 g of pretreated kaolin, 0.5 g of methyl cellulose (pore former), 0.3 g of silica sol (supplementary material), and 0.5 g of potassium hydroxide (activator), grind for 30 min, and then press it into a sheet-shaped carrier precursor with a tablet press;

[0092] 3) Transfer the sheet-shaped carrier precursor to a crystallization kettle, add 5 mL of a 40% by mass tetraethylammonium hydroxide (organic amine solution) to the crystallization kettle, place the carrier precursor above the tetraethylammonium hydroxide without contacting the solution, then seal the crystallization kettle and transfer it to an oven for crystallization at 120 °C for 12 h;

[0093] 4) After the crystallization kettle cools, take out the sheet-shaped carrier precursor and place it in a muffle furnace with a heating and cooling rate of 2 °C / min, keep it at 200 °C for 1 h, and then raise the temperature to 900 °C and calcine for 18 h to obtain a carrier-membrane integrated FAU molecular sieve membrane.

[0094] The carrier-membrane integrated molecular sieve membrane prepared from clay in Example 5 is used for separating methanol and methyl tert-butyl ether, specifically:

[0095] Perform pervaporation testing on the FAU molecular sieve membrane prepared in step 4). The permeation flux of the FAU molecular sieve membrane is 7.2 kg·m -2 ·h -1 , and the methanol / methyl tert-butyl ether permeation selectivity is greater than 10000.

Claims

1. Preparation method of carrier-membrane layer integrated molecular sieve membrane prepared from clay, characterized in that The preparation method includes the following steps: 1) Mix clay, dispersant, pore former, flux, supplementary material and activator evenly, and then form them to obtain a carrier precursor. 2) Place the carrier precursor in a crystallization kettle, seal it and carry out crystallization synthesis. 3) Bake the product obtained in step 2) to form an integrated molecular sieve membrane of carrier and membrane layer. The supplementary material in step 1) is a silicon source, aluminum source or phosphorus source added to ensure the silicon-aluminum ratio, phosphorus-silicon ratio or phosphorus-aluminum ratio in the molecular sieve membrane. In step 2), the crystallization kettle contains an alkali solution, and the carrier precursor is placed above the alkali solution in the crystallization kettle without contacting the alkali solution. The alkali solution is one or more of ammonia water or organic amine solution, and the mass content of ammonia or organic amine in the alkali solution is 10%-99%. In step 3), baking is carried out in a muffle furnace, the baking temperature is 300-1800°C, the baking time is 0.5h-24h, the heating and cooling rate is 0.1-5°C / min, and the temperature is maintained at 200-500°C for 1h-4h during the heating process. The prepared integrated molecular sieve membrane of carrier and membrane layer is used for the separation of homogeneous systems.

2. The preparation method according to claim 1, characterized in that, The clay in step 1) includes one or more of kaolin, montmorillonite, attapulgite, illite, diatomite, sepiolite, hydromica, glauconite, chlorite.

3. The preparation method according to claim 1 or 2, characterized in that, The clay in step 1) is pretreated, and the pretreatment includes high-temperature heat treatment, acid solution treatment and / or alkali solution treatment.

4. The preparation method according to claim 1, characterized in that, In step 1), the content of the dispersant accounts for 0%-50% of the total mass of the carrier precursor. The dispersant includes one or more of water, methanol, ethanol, propanol, ethylene glycol, propylene glycol, butylene glycol, acetone, ether, tetrahydrofuran, dimethyl ether, N-methylpyrrolidone, N,N-dimethylformamide, dimethyl sulfoxide. In step 1), the content of the pore former accounts for 0%-40% of the total mass of the carrier precursor. The pore former includes one or more of high molecular materials or inorganic materials. The high molecular materials include one or more of methyl cellulose, carboxymethyl cellulose, starch, chitosan, urea, polyvinyl chloride, polystyrene, polymethyl methacrylate, polyvinyl butyral, polystyrene, polyethylene glycol, polyethylene, polyvinyl alcohol, polyoxyethylene, polyoxypropylene. The inorganic materials include one or more of wood chips, graphite, carbon powder, carbon black.

5. The preparation method according to claim 1, characterized in that, In step 1), the content of the flux accounts for 0%-10% of the total mass of the carrier precursor. The flux includes one or more of silicon oxide, aluminum oxide, talcum powder, titanium dioxide. In step 1), the content of the activator accounts for 0%-50% of the total mass of the carrier precursor. The activator includes one or more of ammonia water, dimethylamine, trimethylamine, diethylamine, triethylamine, ammonium chloride, sodium chloride, ammonium iodide, ammonium fluoride, sodium fluoride, potassium fluoride, lithium fluoride, ammonium fluorosilicate, ammonium fluoroaluminate, aluminum fluorosilicate, sodium hydroxide, potassium hydroxide, lithium hydroxide, potassium carbonate, lithium carbonate, sodium carbonate, potassium bicarbonate, lithium bicarbonate, sodium bicarbonate, lithium phosphate, sodium phosphate, potassium phosphate, potassium hydrogen phosphate, lithium hydrogen phosphate, sodium hydrogen phosphate, potassium dihydrogen phosphate, lithium dihydrogen phosphate, sodium dihydrogen phosphate.

6. The preparation method according to claim 1, characterized in that, The crystallization temperature in step (2) is 60°C - 220°C, and the crystallization time is 3h - 120h.

7. A clay-supported integrated molecular sieve membrane prepared by the preparation method according to any one of claims 1 - 6.

8. Use of the clay-prepared carrier-membrane integrated molecular sieve membrane according to claim 7, characterized in that, For the separation of homogeneous phase mixture systems.

Images