CN113230907A - Method for preparing LTL type molecular sieve membrane by space limited steam conversion method - Google Patents
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Abstract
The invention belongs to the technical field of molecular sieve membrane preparation, and discloses a method for preparing an LTL type molecular sieve membrane by a space-limited steam conversion method. The reactor reduces the consumption of secondary synthetic liquid, does not waste production raw materials, can quickly and efficiently prepare the LTL type molecular sieve membrane with compact c-axis orientation, and has the advantages of green, environmental protection, economy and easy implementation.
Description
Technical Field
The invention relates to the technical field of molecular sieve membrane preparation, in particular to a method for preparing an LTL type molecular sieve membrane by a space-limited steam conversion method.
Background
The zeolite molecular membrane is one of inorganic membranes, and forms a continuous membrane through intergrowth growth of molecular sieve grains. The method is generally divided into a filling film, an unsupported film and a supported film, wherein the supported film refers to a film grown on a carrier, and the carrier has good mechanical strength, so that the synthesized film has good mechanical strength, and can be subjected to some practical application researches. The molecular sieve particles are used as a catalyst, so that the efficient separation of products and reaction raw materials is difficult to realize, and the molecular sieve particles are orderly arranged to form a continuous membrane structure, so that the separation and the catalysis process can be ingeniously combined, and the molecular sieve membrane has the advantages of artificial zeolite on the basis of the property characteristics of an inorganic membrane.
Currently, in the aspect of molecular sieve membrane synthesis, Yu et al (Microporous and Mesoporous materials.2017, 244: 278-. Yuan-Wenhui et al (report of physico-chemistry 2011, 27 (10): 2493-2498.) assemble PHI molecular sieve grains on an alumina carrier by a dipping method, and prepare PHI molecular sieve films by a two-step hydrothermal growth method. Tong et al (Microporous and Mesoporous materials.2015, 213: 1-7.) prepared nano NaA/glass films using a layered in situ sol-gel process in combination with steam assisted conversion techniques. Li et al (Journal of Membrane science.2006, 277 (1): 230-. Rong et al (Science China Materials 2020, 64 (2): 374-382.) propose the synthesis of pure silicon MFI molecular sieve membranes with submicron thickness by surface gel conversion.
The traditional molecular sieve membrane preparation methods have the defects of extremely low raw material utilization rate, complex operation and the like, and the high raw material cost is generated, so that a large amount of three wastes are discharged, and the method does not accord with the concept of green chemistry. The gel-free synthesis method avoids the use of a large amount of mother liquor, has high utilization rate of raw materials, and is a recent research hotspot. However, the existing sol-free method has complex steps, is lack of understanding of a film forming mechanism and key parameters, and is difficult to popularize and utilize. Therefore, it is necessary to provide a method for preparing a molecular sieve membrane with high efficiency, easy operation, economy and environmental protection to solve the problems encountered at present.
Disclosure of Invention
The invention aims to provide a method for preparing an LTL type molecular sieve membrane by a space-limited steam conversion method, which overcomes the defects of the existing preparation method and meets the requirements of different fields.
In order to achieve the above object, the present invention provides the following technical solutions:
the invention provides a method for preparing an LTL type molecular sieve membrane by a space-limited steam conversion method, which comprises the following steps:
(1) preparation of LTL type molecular sieve crystal grain: mixing an aluminum source, an alkali source, a silicon source and deionized water, and carrying out hydrothermal crystallization to obtain LTL type molecular sieve grains;
(2) modification of LTL type molecular sieve crystal grain: mixing LTL type molecular sieve crystal grains with a hydrochloric acid solution, reacting for 0.5-2 h, washing to be neutral, then ultrasonically dispersing into a sec-butyl alcohol solution, and stirring to obtain a modified LTL type molecular sieve suspension;
(3) modification of the vector: modifying the GO dispersion liquid on the surface of the carrier by using a suction filtration method, and drying to obtain a GO modified carrier;
(4) assembling LTL type molecular sieve crystal grain layers: assembling the modified LTL type molecular sieve suspension obtained in the step (2) on the GO modified carrier obtained in the step (3) by using a suction filtration method, and drying to obtain an LTL type molecular sieve crystal grain layer;
(5) preparation of LTL type molecular sieve membrane: and mixing an aluminum source, an alkali source, a silicon source and deionized water to prepare a secondary synthetic liquid, coating the secondary synthetic liquid on the surface of the crystal grain layer of the LTL type molecular sieve by adopting a spin coating method, placing the crystal grain layer in a space-limited steam conversion reactor, adding deionized water, sealing, and heating for reaction to obtain the LTL type molecular sieve membrane.
Preferably, in the step (1), the aluminum source, the alkali source, the silicon source and the deionized water are respectively Al2O3、K2O、SiO2And H2O represents the same or different2O3、K2O、SiO2And H2The molar ratio of O is 1: 7-10: 20-25: 300-800.
Preferably, the aluminum source in the step (1) is one or more of aluminum sulfate octadecahydrate, aluminum powder and aluminum hydroxide; the alkali source is one or two of potassium hydroxide and sodium hydroxide; the silicon source is one or more of silica sol, white carbon black, fumed silica and water glass.
Preferably, the hydrothermal crystallization temperature in the step (1) is 160-200 ℃, and the time is 12-48 h.
Preferably, the volume ratio of the mass of the LTL type molecular sieve crystal grains to the hydrochloric acid solution in the step (2) is 1g: 15-30 mL; the concentration of the hydrochloric acid solution is 0.5-3 mol/L.
Preferably, the mass concentration of the modified LTL type molecular sieve suspension in the step (2) is 0.5-2 wt%.
Preferably, the suction filtration method in the step (3) comprises the following specific steps:
placing the carrier in a suction filtration device, keeping the surface level of the carrier, adding deionized water to the surface of the carrier, starting a vacuum pump, dropwise adding GO dispersion liquid, standing for 1-10 min after the deionized water is completely settled, and closing the vacuum pump.
Preferably, the carrier in the step (3) is alumina, silica or zirconia.
Preferably, the GO dispersing liquid in the step (3) is obtained by dispersing GO in a mixed solution of methanol and deionized water, and the mass ratio of GO to deionized water to methanol is 1-2: 10-12: 40-50.
Preferably, the mass ratio of the surface area of the carrier to the GO dispersion liquid in the step (3) is 1: 170-180 m2/g。
Preferably, the suction filtration method in the step (4) comprises the following specific steps:
placing the GO modified carrier in a suction filtration device, keeping the surface level of the carrier, adding deionized water to the surface of the carrier, starting a vacuum pump, dropwise adding modified LTL type molecular sieve turbid liquid, standing for 1-10 min after the deionized water is completely settled, and closing the vacuum pump.
Preferably, the mass ratio of the surface area of the GO modified carrier to the mass of the modified LTL type molecular sieve suspension in the step (4) is 1-5: 900-1200 m2/g。
Preferably, the aluminum source, the alkali source, the silicon source and the deionized water of the secondary synthetic solution in the step (5) are respectively Al2O3、K2O、SiO2And H2O represents the same or different2O3、K2O、SiO2And H2The molar ratio of O is 1: 7-10: 20-25: 300-800.
Preferably, the rotation speed of the secondary synthesis solution spin coating in the step (5) is 2000-3000 r/min, and the spin coating time is 30-60 s.
Preferably, the mass of the deionized water in the step (5) is 0.02-0.04 g.
Preferably, the space-limited steam reforming reactor in the step (5) has a polytetrafluoroethylene inner liner and a stainless steel outer liner, and the inner liner has a sealing cover.
Preferably, the heating reaction in the step (5) is carried out at the temperature of 180-200 ℃ for 48-72 hours.
Through the technical scheme, compared with the prior art, the invention has the following beneficial effects:
the invention synthesizes the LTL type molecular sieve membrane by utilizing the self-made space limited steam reforming reactor, greatly reduces the consumption of secondary synthetic liquid, does not waste production raw materials, can quickly and efficiently prepare the LTL type molecular sieve membrane with compact c-axis orientation, and has the advantages of environmental protection, economy and easy implementation.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below.
FIG. 1 is a representation of the LTL-type molecular sieve crystallites prepared in step (1) of example 1;
wherein, (a) is SEM picture of LTL type molecular sieve crystal grain; (b) is an XRD pattern of LTL type molecular sieve grains; (c) is a schematic view of the c-axis orientation of LTL type molecular sieve grains;
FIG. 2 is a characterization plot of the GO-modified alumina support prepared in step (3) of example 1;
wherein, (a) is SEM picture of unmodified alumina carrier; (b) is SEM picture of GO modified alumina carrier; (c) is an XRD pattern of the GO modified alumina carrier; (d) is a Raman spectrum of the GO modified alumina carrier;
FIG. 3 is a representation of the LTL-type molecular sieve grain layer prepared in step (4) of example 1;
wherein (a) is an SEM image of an LTL type molecular sieve crystal grain layer; (b) is an XRD pattern of an LTL type molecular sieve grain layer;
FIG. 4 is an SEM image of an LTL-type molecular sieve membrane prepared in example 1;
wherein, (a) is a surface SEM image; (b) is a cross-sectional SEM image;
FIG. 5 is an SEM image of an LTL-type molecular sieve membrane prepared in example 2;
wherein, (a) is a surface SEM image; (b) is a cross-sectional SEM image;
fig. 6 is an XRD pattern of the LTL-type molecular sieve membranes prepared in example 1 and example 2;
FIG. 7 shows the LTL type molecular sieve membrane pair H prepared in example 12、CO2The permeate flux and ideal selectivity line profile of;
FIG. 8 shows the LTL type molecular sieve membrane pair H prepared in example 22、CO2Permeate flux and ideal selectivity line profile.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention provides a method for preparing an LTL type molecular sieve membrane by a space-limited steam conversion method, which comprises the following steps:
(1) preparation of LTL type molecular sieve crystal grain: mixing an aluminum source, an alkali source, a silicon source and deionized water, and carrying out hydrothermal crystallization to obtain LTL type molecular sieve grains; the method comprises the following specific steps:
dissolving an aluminum source and an alkali source in deionized water, stirring for 3h to obtain a solution A, dissolving a silicon source in deionized water, hydrolyzing to obtain a solution B, slowly dripping the solution A into the solution B, aging at room temperature for 3h, performing hydrothermal crystallization at 160-200 ℃ for 12-48 h, washing the obtained product with ammonia water and deionized water in sequence, centrifuging, and drying;
(2) modification of LTL type molecular sieve crystal grain: mixing LTL type molecular sieve crystal particles with 0.5-3 mol/L hydrochloric acid solution according to the mass volume ratio of 1g: 15-30 mL, reacting at 80 ℃ for 0.5-2 h, washing to be neutral by using deionized water, drying at 110 ℃, then ultrasonically dispersing into sec-butyl alcohol solution to prepare suspension liquid with the mass concentration of 0.5-2 wt%, and stirring and modifying for 7 days to obtain modified LTL type molecular sieve suspension liquid;
(3) modification of the vector: dispersing GO into a mixed solution of methanol and deionized water according to the mass ratio of GO, deionized water and methanol of 1-2: 10-12: 40-50 to prepare GO dispersion liquid, placing a carrier in a suction filtration device, keeping the surface of the carrier horizontal, adding deionized water without the surface of the carrier, starting a vacuum pump, dropwise adding the GO dispersion liquid after the pressure of the vacuum pump reaches-0.1 MPa and is stable, standing for 1-10 min after the deionized water is completely settled, closing the vacuum pump, and drying the product at 60 ℃ to obtain a GO modified carrier;
(4) assembling LTL type molecular sieve crystal grain layers: placing the GO modified carrier in a suction filtration device, keeping the surface of the carrier horizontal, adding deionized water to the surface of the carrier, starting a vacuum pump, dropwise adding a modified LTL type molecular sieve suspension after the pressure of the vacuum pump reaches-0.1 MPa and is stable, standing for 1-10 min after the deionized water is completely settled, closing the vacuum pump, and drying the product at 80 ℃ to obtain an LTL type molecular sieve crystal grain layer;
(5) preparation of LTL type molecular sieve membrane: mixing an aluminum source, an alkali source, a silicon source and deionized water to prepare a secondary synthetic liquid, coating the secondary synthetic liquid on the surface of the crystal grain layer of the LTL-type molecular sieve by adopting a spin coating method, wherein the spin coating speed is 2000-3000 r/min, the spin coating time is 30-60 s, placing the secondary synthetic liquid in a space limited steam conversion reactor, adding 0.02-0.04 g of deionized water, sealing, and carrying out heating reaction at 180-200 ℃ for 48-72 h to obtain the LTL-type molecular sieve membrane.
Preferably, in the step (1), the aluminum source, the alkali source, the silicon source and the deionized water are respectively Al2O3、K2O、SiO2And H2O represents Al2O3、K2O、SiO2And H2The molar ratio of O is 1: 7-10: 20-25: 300-800, and more preferably 1:10:20: 300.
Preferably, the mass ratio of the surface area of the carrier to the GO dispersion liquid in the step (3) is 1: 170-180 m2(iv)/g, more preferably 1:174m2/g。
Preferably, the mass ratio of the surface area of the GO modified carrier to the mass of the modified LTL type molecular sieve suspension in the step (4) is 1-5: 900-1200 m2(iv)/g, more preferably 3:1000m2/g。
Preferably, in the step (5), the aluminum source, the alkali source, the silicon source and the deionized water are respectively Al2O3、K2O、SiO2And H2O represents Al2O3、K2O、SiO2And H2The molar ratio of O is 1: 7-10: 20-25: 300-800, and more preferably 1:10:20: 300.
Example 1
The invention provides a method for preparing an LTL type molecular sieve membrane by a space-limited steam conversion method, which comprises the following steps:
(1) preparation of LTL type molecular sieve crystal grain: mixing Al2(SO4)3·18H2Dissolving O and KOH in deionized water, stirring for 3h to obtain solution A, dissolving a silicon source Ludox-As-40 in deionized water, hydrolyzing to obtain solution B, slowly dripping the solution A into the solution B to obtain Al2O3、K2O、SiO2And H2Aging the LTL type molecular sieve synthetic solution with the molar ratio of O being 1:10:20:300 at room temperature for 3h, performing hydrothermal crystallization at 180 ℃ for 24h, washing the obtained product with ammonia water and deionized water in sequence, centrifuging, and drying to obtain LTL type molecular sieve grains;
(2) modification of LTL type molecular sieve crystal grain: mixing 1g of LTL type molecular sieve crystal particles with 20mL of hydrochloric acid solution of 2mol/L, reacting at 80 ℃ for 1h, washing to be neutral by using deionized water, drying at 110 ℃, then ultrasonically dispersing into sec-butyl alcohol solution to prepare suspension with the mass concentration of 0.5 wt%, and stirring and modifying for 7d to obtain modified LTL type molecular sieve suspension;
(3) modification of the vector: 1g of GO is dispersed in a mixed solution of 50g of methanol and 11g of deionized water to prepare GO dispersion liquid, and the surface area is about 2.3 multiplied by 10-4m2Placing the alumina carrier in a suction filtration device, keeping the surface of the carrier horizontal, adding deionized water to the surface of the carrier, starting a vacuum pump, removing impurities or bubbles on the liquid surface after the pressure of the vacuum pump reaches-0.1 MPa and is stable, dropwise adding 0.4g of GO dispersion liquid after the liquid surface is stable, standing for 3min after the deionized water is completely settled, closing the vacuum pump, and drying the product at 60 ℃ to obtain the GO modified alumina carrier;
(4) assembling LTL type molecular sieve crystal grain layers: the surface area is about 2.3X 10-4m2Placing the GO modified alumina carrier in a suction filtration device, keeping the surface of the carrier horizontal, adding deionized water to the surface of the carrier, starting a vacuum pump, removing impurities or bubbles on the liquid surface after the pressure of the vacuum pump reaches-0.1 MPa and is stable, dropwise adding 0.076g of modified LTL type molecular sieve suspension after the liquid surface is stable, standing for 3min after the deionized water is completely settled, closing the vacuum pump, and drying the product at 80 ℃ to obtain an LTL type molecular sieve crystal grain layer;
(5) preparation of LTL type molecular sieve membrane: mixing Al2(SO4)3·18H2Dissolving O and KOH in deionized water, stirring for 3h to obtain solution A, dissolving a silicon source Ludox-As-40 in deionized water, hydrolyzing to obtain solution B, slowly dripping the solution A into the solution B to obtain Al2O3、K2O、SiO2And H2Coating 0.5mL of the secondary synthetic solution with the molar ratio of O of 1:10:20:300 on a 3.8X 10 by a spin coater at the rotation speed of 2000r/min-4g LTL type molecular sieve grain layer surface, spin coating time is 40s, placing in space limited steam conversion reactor, adding 0.04g deionized water, sealing and reactingAnd heating the reactor at 180 ℃ for reaction for 48 hours to obtain the LTL type molecular sieve membrane.
And (3) characterizing the LTL type molecular sieve crystal grains prepared in the step (1), wherein the result is shown in figure 1. As can be seen from FIG. 1, the crystal grains of the prepared LTL-type molecular sieve are disc-shaped, the diameter is about 1.5 μm, the thickness is about 0.2 μm, and the characteristic peak of the LTL-type molecular sieve appears between 3 degrees and 50 degrees as seen from an XRD (X-ray diffraction) pattern, which indicates that the prepared product is the LTL-type molecular sieve.
And (4) carrying out characterization on the GO modified carrier prepared in the step (3), wherein the result is shown in figure 2. As can be seen from fig. 2, large pores and depressions exist on the surface of an unmodified alumina, GO completely covers the surface of alumina after GO modification, and defects existing on the surface of GO are modified; the peak of GO is known to appear between 10-15 degrees by XRD atlas, which shows that GO has no chemical change in the modification process; according to a Raman spectrum, the GO modified alumina carrier has D peaks and G peaks which are basically as high as the same, and the GO membrane structure after suction filtration assembly is regular.
And (3) characterizing the LTL type molecular sieve grain layer prepared in the step (4), wherein the result is shown in figure 3. As can be seen from FIG. 3, the LTL type molecular sieve grains assembled by the suction filtration method are regularly and orderly arranged on the carrier, and the (001) and (002) crystal face diffraction peaks in the XRD spectrum are stronger, which indicates that the grain layer is in c-axis orientation.
The LTL type molecular sieve membrane prepared in the step (5) is characterized, and the results are shown in FIG. 4 and FIG. 6. As can be seen from FIG. 4, the prepared LTL type molecular sieve membrane has a compact surface without major defects, and a clear cross section, with a membrane thickness of about 2 μm. As can be seen from fig. 6, the characteristic peaks of the LTL-type molecular sieve appear in the XRD spectrum between 3 ° and 50 °, and the characteristic peaks of the (001), (002) and (004) crystal planes are strong, indicating that the film has c-axis orientation.
Testing the gas permeation separation performance of the LTL type molecular sieve membrane:
the LTL type molecular sieve membrane prepared in example 1 was subjected to single-component H at room temperature2、CO2Testing gas permeation separation performance, testing compactness of membrane layer, and measuring H2/CO2The results are shown in FIG. 7. As can be seen from FIG. 7, H increases with the pressure of the test gas2、CO2The permeation flux of (2) is continuously increased, and H is increased at 0.1MPa2Has a permeation flux of 9.0X 10- 8mol·m-2·Pa-1·s-1，CO2Has a permeation flux of 1.07X 10-9mol·m-2·Pa-1·s-1When the ideal selectivity is as high as 84 and higher than the Knudsen diffusion coefficient of 4.7, the film is proved to be compact and free of defects and has H resistance2/CO2Has high selectivity.
Example 2
The invention provides a method for preparing an LTL type molecular sieve membrane by a space-limited steam reforming method, which specifically comprises the following steps of example 1, and is different from example 1 in that the heating reaction in the step (5) is heating reaction at 180 ℃ for 72 hours.
The obtained LTL type molecular sieve membrane was characterized, and the results are shown in FIGS. 5 and 6. As can be seen from FIG. 5, the prepared LTL type molecular sieve membrane has a compact surface without major defects, and a clear cross section, with a membrane thickness of about 600 nm. As can be seen from fig. 6, the characteristic peaks of the LTL-type molecular sieve appear in the XRD spectrum between 3 ° and 50 °, and the characteristic peaks of the (001), (002) and (004) crystal planes are strong, indicating that the film has c-axis orientation.
Testing the gas permeation separation performance of the LTL type molecular sieve membrane:
the LTL type molecular sieve membrane prepared in example 2 was subjected to single-component H at room temperature2、CO2Testing gas permeation separation performance, testing compactness of membrane layer, and measuring H2/CO2The results are shown in FIG. 8. As can be seen from FIG. 8, as the pressure of the test gas increases, H2、CO2The permeation flux of (2) is continuously increased, and H is increased at 0.05MPa2Has a permeation flux of 1.39X 10-6mol·m-2·Pa-1·s-1，CO2Has a permeation flux of 7.78X 10-8mol·m-2·Pa-1·s-1The ideal selectivity can reach 17.9, which is higher than the Knudsen diffusion coefficient 4.7, and the film is proved to be compact and free of defects and has H resistance2/CO2Has better selectivity.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.
Claims (10)
1. A method for preparing an LTL type molecular sieve membrane by a space-limited steam conversion method is characterized by comprising the following steps:
(1) preparation of LTL type molecular sieve crystal grain: mixing an aluminum source, an alkali source, a silicon source and deionized water, and carrying out hydrothermal crystallization to obtain LTL type molecular sieve grains;
(2) modification of LTL type molecular sieve crystal grain: mixing LTL type molecular sieve crystal grains with a hydrochloric acid solution, reacting for 0.5-2 h, washing to be neutral, then ultrasonically dispersing into a sec-butyl alcohol solution, and stirring to obtain a modified LTL type molecular sieve suspension;
(3) modification of the vector: modifying the GO dispersion liquid on the surface of the carrier by using a suction filtration method, and drying to obtain a GO modified carrier;
(4) assembling LTL type molecular sieve crystal grain layers: assembling the modified LTL type molecular sieve suspension obtained in the step (2) on the surface of the GO modified carrier obtained in the step (3) by using a suction filtration method, and drying to obtain an LTL type molecular sieve crystal grain layer;
(5) preparation of LTL type molecular sieve membrane: and mixing an aluminum source, an alkali source, a silicon source and deionized water to prepare a secondary synthetic liquid, coating the secondary synthetic liquid on the surface of the crystal grain layer of the LTL type molecular sieve by adopting a spin coating method, placing the crystal grain layer in a space-limited steam conversion reactor, adding deionized water, sealing, and heating for reaction to obtain the LTL type molecular sieve membrane.
2. The method for preparing LTL-type molecular sieve membrane by using spatially limited steam reforming method according to claim 1, wherein in the step (1), Al, alkali, Si and DI water are respectively added to Al2O3、K2O、SiO2And H2O represents the same or different2O3、K2O、SiO2And H2The molar ratio of O is 1: 7-10: 20-25: 300-800.
3. The method for preparing the LTL-type molecular sieve membrane by the space-limited steam reforming method according to claim 2, wherein the volume ratio of the mass of the LTL-type molecular sieve crystal grains to the hydrochloric acid solution in the step (2) is 1g: 15-30 mL; the mass concentration of the modified LTL type molecular sieve suspension is 0.5-2 wt%.
4. The method for preparing the LTL-type molecular sieve membrane by the space-limited steam reforming method according to any one of claims 1 to 3, wherein the suction filtration method in the step (3) comprises the following specific steps:
placing the carrier in a suction filtration device, keeping the surface level of the carrier, adding deionized water to the surface of the carrier, starting a vacuum pump, dropwise adding GO dispersion liquid, standing for 1-10 min after the deionized water is completely settled, and closing the vacuum pump.
5. The method for preparing LTL-type molecular sieve membrane by using the spatially limited steam reforming method according to claim 4, wherein the carrier in the step (3) is alumina, silica or zirconia.
6. The method for preparing the LTL-type molecular sieve membrane by the space-limited steam reforming method according to claim 3, wherein the suction filtration method in the step (4) comprises the following specific steps:
placing the GO modified carrier in a suction filtration device, keeping the surface level of the carrier, adding deionized water to the surface of the carrier, starting a vacuum pump, dropwise adding modified LTL type molecular sieve turbid liquid, standing for 1-10 min after the deionized water is completely settled, and closing the vacuum pump.
7. The method for preparing the LTL-type molecular sieve membrane by the space-limited steam reforming method according to claim 6, wherein the mass ratio of the area of the GO modified carrier to the mass of the modified LTL-type molecular sieve suspension in the step (4) is 1-5: 900-1200 m2/g。
8.The method for preparing LTL-type molecular sieve membrane by using spatially-limited steam reforming method according to claim 6 or 7, wherein the aluminum source, the alkali source, the silicon source and the deionized water of the secondary synthesis solution in the step (5) are respectively Al2O3、K2O、SiO2And H2O represents the same or different2O3、K2O、SiO2And H2The molar ratio of O is 1: 7-10: 20-25: 300-800.
9. The method for preparing the LTL-type molecular sieve membrane by the space-limited steam reforming method according to claim 8, wherein the spin-coating speed of the secondary synthesis solution in the step (5) is 2000-3000 r/min, and the spin-coating time is 30-60 s.
10. The method for preparing LTL type molecular sieve membrane by space-limited steam reforming method according to claim 1 or 9, wherein the space-limited steam reforming reactor in step (5) has an inner lining of polytetrafluoroethylene and an outer lining of stainless steel, and the inner lining has a sealing cover.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114210212A (en) * | 2021-12-21 | 2022-03-22 | 江西师范大学 | L-type molecular sieve membrane, preparation method thereof and application thereof in desalination |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105727757A (en) * | 2016-03-18 | 2016-07-06 | 宁夏大学 | Preparation method of orientation LTL type molecular sieving membrane for gas separation |
| WO2016177355A1 (en) * | 2015-05-07 | 2016-11-10 | Forschungszentrum Jülich GmbH | Carbon-containing membrane for water and gas separation |
| CN109012224A (en) * | 2018-09-14 | 2018-12-18 | 北京工业大学 | The method that a kind of nanometer of confinement growth in situ prepares ZIF-8@graphene oxide hybridized film |
| CN109956464A (en) * | 2018-08-07 | 2019-07-02 | 江苏九天高科技股份有限公司 | A kind of NaA molecular sieve membrane, preparation method and its usage |
| CN112426891A (en) * | 2020-10-09 | 2021-03-02 | 大连理工大学 | Preparation method of CHA-type zeolite molecular sieve membrane |
-
2021
- 2021-05-17 CN CN202110536606.7A patent/CN113230907B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2016177355A1 (en) * | 2015-05-07 | 2016-11-10 | Forschungszentrum Jülich GmbH | Carbon-containing membrane for water and gas separation |
| CN105727757A (en) * | 2016-03-18 | 2016-07-06 | 宁夏大学 | Preparation method of orientation LTL type molecular sieving membrane for gas separation |
| CN109956464A (en) * | 2018-08-07 | 2019-07-02 | 江苏九天高科技股份有限公司 | A kind of NaA molecular sieve membrane, preparation method and its usage |
| CN109012224A (en) * | 2018-09-14 | 2018-12-18 | 北京工业大学 | The method that a kind of nanometer of confinement growth in situ prepares ZIF-8@graphene oxide hybridized film |
| CN112426891A (en) * | 2020-10-09 | 2021-03-02 | 大连理工大学 | Preparation method of CHA-type zeolite molecular sieve membrane |
Non-Patent Citations (1)
| Title |
|---|
| 王佳明: "基于氧化石墨烯限域作用制备MFI型分子筛膜", 《中国优秀博硕士学位论文全文数据库(硕士)工程科技Ⅰ辑》 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114210212A (en) * | 2021-12-21 | 2022-03-22 | 江西师范大学 | L-type molecular sieve membrane, preparation method thereof and application thereof in desalination |
| CN114210212B (en) * | 2021-12-21 | 2023-10-27 | 江西师范大学 | L-shaped molecular sieve membrane, preparation method thereof and application thereof in desalination |
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