CN113230907B - Method for preparing LTL type molecular sieve membrane by space-limited steam conversion method - Google Patents
Method for preparing LTL type molecular sieve membrane by space-limited steam conversion method Download PDFInfo
- Publication number
- CN113230907B CN113230907B CN202110536606.7A CN202110536606A CN113230907B CN 113230907 B CN113230907 B CN 113230907B CN 202110536606 A CN202110536606 A CN 202110536606A CN 113230907 B CN113230907 B CN 113230907B
- Authority
- CN
- China
- Prior art keywords
- molecular sieve
- type molecular
- ltl
- deionized water
- carrier
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
- B01D71/02—Inorganic material
- B01D71/028—Molecular sieves
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/22—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by diffusion
- B01D53/228—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by diffusion characterised by specific membranes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D65/00—Accessories or auxiliary operations, in general, for separation processes or apparatus using semi-permeable membranes
- B01D65/10—Testing of membranes or membrane apparatus; Detecting or repairing leaks
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
- B01D67/0039—Inorganic membrane manufacture
- B01D67/0041—Inorganic membrane manufacture by agglomeration of particles in the dry state
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/10—Supported membranes; Membrane supports
- B01D69/105—Support pretreatment
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/12—Composite membranes; Ultra-thin membranes
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B39/00—Compounds having molecular sieve and base-exchange properties, e.g. crystalline zeolites; Their preparation; After-treatment, e.g. ion-exchange or dealumination
- C01B39/02—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof; Direct preparation thereof; Preparation thereof starting from a reaction mixture containing a crystalline zeolite of another type, or from preformed reactants; After-treatment thereof
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2002/00—Crystal-structural characteristics
- C01P2002/70—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data
- C01P2002/72—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data by d-values or two theta-values, e.g. as X-ray diagram
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/01—Particle morphology depicted by an image
- C01P2004/03—Particle morphology depicted by an image obtained by SEM
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 dosage of secondary synthetic liquid, does not waste production raw materials, can rapidly and efficiently prepare the LTL type molecular sieve membrane with compact c-axis orientation, and has the advantages of environment-friendly preparation method, economy and practicability.
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
Zeolite molecular films are one type of inorganic film that forms a continuous film by intergrowth of molecular sieve grains. The support film refers to a film grown on a carrier, and the carrier has good mechanical strength, so that the mechanical strength of the synthesized film is also good, and some practical application researches can be performed. The molecular sieve particles are used as catalysts, so that the efficient separation of products and reaction raw materials is difficult to realize, and the molecular sieve particles are orderly distributed to form a continuous membrane layer structure, so that the separation and catalysis processes can be skillfully combined together, and the molecular sieve membrane has the advantages of artificial zeolite on the basis of the characteristic of an inorganic membrane.
In the aspect of molecular sieve membrane synthesis, yu et al (Microporous and Mesoporous materials.2017, 244:278-283.) have studied a method for preparing a hollow fiber NaA zeolite membrane by a chitosan-assisted in-situ impregnation-hydrothermal crystallization method. Yuan Wenhui et al (journal of Physics and chemistry 2011, 27 (10): 2493-2498.) assembled PHI molecular sieve grains on alumina supports by impregnation and prepared PHI molecular sieve membranes by secondary hydrothermal growth. Tong et al (Microporous and Mesoporous materials.2015, 213:1-7.) prepared nano NaA/glass films using a layered in situ sol-gel method in combination with steam assisted transformation techniques. Li et al (Journal of Membrane science.2006, 277 (1): 230-239.) successfully synthesized high quality LTA zeolite membranes using microwave heating techniques. Rong et al (Science China Materials, 64 (2): 374-382.) propose a surface gel conversion process to synthesize a pure silicon MFI molecular sieve membrane of submicron thickness.
The traditional molecular sieve membrane preparation method has the defects of extremely low raw material utilization rate, complex operation and the like, and has higher raw material cost, 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 raw material utilization rate and is a recent research hot spot. However, the existing sol-free method has complex steps, lacks knowledge of a film forming mechanism and key parameters, and is difficult to popularize and use. Therefore, a preparation method of a molecular sieve membrane with high efficiency, easy implementation, economy and environmental protection is needed 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, so as to overcome the defects of the existing preparation method and meet 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 grains: mixing an aluminum source, an alkali source, a silicon source and deionized water, and performing hydrothermal crystallization to obtain LTL type molecular sieve grains;
(2) Modification of LTL type molecular sieve crystal grains: mixing LTL type molecular sieve crystal grains with hydrochloric acid solution, reacting for 0.5-2 h, washing to neutrality, then ultrasonically dispersing into sec-butyl alcohol solution, and stirring to obtain 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 an LTL type molecular sieve grain layer: assembling the modified LTL type molecular sieve suspension in the step (2) on the GO modified carrier in the step (3) by using a suction filtration method, and drying to obtain an LTL type molecular sieve 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 solution, coating the secondary synthetic solution on the surface of an LTL molecular sieve grain layer by adopting a spin coating method, placing the secondary synthetic solution in a space-limited steam conversion reactor, adding deionized water, sealing, and heating for reaction to obtain the LTL molecular sieve membrane.
Preferably, in the step (1), the aluminum source, the alkali source, the silicon source and the deionized water are respectively prepared by Al 2 O 3 、K 2 O、SiO 2 And H 2 O represents, the Al 2 O 3 、K 2 O、SiO 2 And H 2 The mol 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 octadecabydrate, 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 mass ratio of the LTL type molecular sieve crystal grains in the step (2) to the hydrochloric acid solution is 1 g: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 specific steps of the suction filtration method in the step (3) are as follows:
placing the carrier in a suction filtration device, keeping the surface level of the carrier, adding deionized water without overload surface, 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 dispersion liquid in the step (3) is a mixed solution of GO dispersed in 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 in the step (3) is 1:170-180 m 2 /g。
Preferably, the specific steps of the suction filtration method in the step (4) are as follows:
placing the GO modified carrier in a suction filtration device, keeping the surface level of the carrier, adding deionized water without the surface of the carrier, starting a vacuum pump, dropwise adding modified LTL type molecular sieve suspension, 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 modified LTL type molecular sieve suspension in the step (4) is 1-5:900-1200 m 2 /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 prepared by Al 2 O 3 、K 2 O、SiO 2 And H 2 O represents, the Al 2 O 3 、K 2 O、SiO 2 And H 2 The mol ratio of O is 1:7-10:20-25:300-800.
Preferably, the rotation speed of the spin coating of the secondary synthetic liquid in the step (5) is 2000-3000 r/min, and the spin coating time is 30-60 s.
Preferably, the mass of deionized water in the step (5) is 0.02-0.04 g.
Preferably, the space-limited steam reforming reactor in 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 180-200 ℃ for 48-72 h.
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 rapidly and efficiently prepare the LTL type molecular sieve membrane with compact c-axis orientation, and has the advantages of environment-friendly preparation method, economy and practicability.
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 graph showing the characterization of LTL-type molecular sieve grains prepared in step (1) of example 1;
wherein, (a) is an SEM image of LTL molecular sieve grains; (b) is the XRD pattern of LTL molecular sieve crystallites; (c) is a schematic representation of the c-axis orientation of LTL-type molecular sieve grains;
FIG. 2 is a graph depicting the characterization of GO-modified alumina supports prepared in step (3) of example 1;
wherein, (a) is an SEM image of an unmodified alumina support; (b) is SEM image of GO-modified alumina carrier; (c) is the XRD pattern of the GO-modified alumina carrier; (d) is a raman spectrum of the GO-modified alumina carrier;
FIG. 3 is a graph showing the characterization of the crystalline layer of LTL-type molecular sieve prepared in step (4) of example 1;
wherein, (a) is an SEM image of an LTL molecular sieve grain layer; (b) is the XRD pattern of the LTL 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 LTL-type molecular sieve membranes prepared in example 1 and example 2;
FIG. 7 shows the LTL molecular sieve membrane pair H prepared in example 1 2 、CO 2 A permeation flux and ideal selectivity profile of (c);
FIG. 8 shows the LTL molecular sieve membrane pair H prepared in example 2 2 、CO 2 And a plot of permeate flux versus desired selectivity.
Detailed Description
The following description of the technical solutions in the embodiments of the present invention will be clear and complete, and it is obvious that the described embodiments are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the 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 grains: mixing an aluminum source, an alkali source, a silicon source and deionized water, and performing 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 3 hours to obtain a solution A, dissolving a silicon source in the deionized water, hydrolyzing to obtain a solution B, slowly dripping the solution A into the solution B, aging for 3 hours at room temperature, performing hydrothermal crystallization for 12-48 hours at 160-200 ℃, washing the obtained product with ammonia water and deionized water in sequence, centrifuging, and drying;
(2) Modification of LTL type molecular sieve crystal grains: mixing LTL type molecular sieve crystal grains with 0.5-3 mol/L hydrochloric acid solution according to the mass volume ratio of 1 g:15-30 mL, reacting for 0.5-2 h at 80 ℃, washing to be neutral by deionized water, drying at 110 ℃, then dispersing into sec-butyl alcohol solution by ultrasonic to prepare a suspension with the mass concentration of 0.5-2 wt%, and stirring and modifying for 7d to obtain modified LTL type molecular sieve suspension;
(3) Modification of the vector: dispersing GO in a mixed solution of methanol and deionized water according to the mass ratio of GO to deionized water to methanol of 1-2:10-12:40-50 to prepare GO dispersion, placing a carrier in a suction filtration device, keeping the surface level of the carrier, adding deionized water without overload surface, starting a vacuum pump, dropwise adding the GO dispersion 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 an LTL type molecular sieve grain layer: placing the GO modified carrier in a suction filtration device, keeping the surface level of the carrier, adding deionized water without overload surface, starting a vacuum pump, dropwise adding modified LTL type molecular sieve suspension after the vacuum pump pressure 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 solution, coating the secondary synthetic solution on the surface of an LTL molecular sieve crystal grain layer 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 solution in a space-limited steam conversion reactor, adding 0.02-0.04 g of deionized water, sealing, and heating and reacting at 180-200 ℃ for 48-72 h to obtain the LTL molecular sieve film.
Preferably, in step (1), the aluminum source, the alkali source, the silicon source and the deionized water are respectively prepared by using Al 2 O 3 、K 2 O、SiO 2 And H 2 O represents, al 2 O 3 、K 2 O、SiO 2 And H 2 The molar ratio of O is 1:7 to 10:20 to 25:300 to 800, more preferably 1:10:20:300.
Preferably, the mass ratio of the surface area of the carrier to the GO dispersion in step (3) is 1:170-180 m 2 Preferably 1:174m 2 /g。
Preferably, the mass ratio of the surface area of the GO modified carrier to the modified LTL type molecular sieve suspension in the step (4) is 1-5:900-1200 m 2 Preferably 3:1000m 2 /g。
Preferably, in step (5), the aluminum source, the alkali source, the silicon source and the deionized water are respectively prepared by using Al 2 O 3 、K 2 O、SiO 2 And H 2 O represents, al 2 O 3 、K 2 O、SiO 2 And H 2 The molar ratio of O is 1:7 to 10:20 to 25:300 to 800, 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 grains: al is added with 2 (SO 4 ) 3 ·18H 2 O and KOH are dissolved in deionized water, stirred for 3 hours to obtain solution A, silicon source Ludox-As-40 is dissolved in deionized water, solution B is obtained by hydrolysis, and solution A is slowly dripped into solution B to obtain Al 2 O 3 、K 2 O、SiO 2 And H 2 Aging the LTL type molecular sieve synthetic solution with the molar ratio of O of 1:10:20:300 for 3 hours at room temperature, performing hydrothermal crystallization for 24 hours at 180 ℃, washing the obtained product with ammonia water and deionized water in sequence, centrifuging, and drying to obtain LTL type molecular sieve crystal grains;
(2) Modification of LTL type molecular sieve crystal grains: mixing 1g of LTL type molecular sieve crystal grains with 20mL of 2mol/L hydrochloric acid solution, reacting for 1h at 80 ℃, washing to be neutral by deionized water, drying at 110 ℃, then dispersing into sec-butyl alcohol solution by ultrasonic to prepare a suspension with the mass concentration of 0.5wt%, and stirring for 7d to obtain a modified LTL type molecular sieve suspension;
(3) Modification of the vector: dispersing 1g GO in a mixed solution of 50g methanol and 11g deionized water to obtain GO dispersion, and preparing the GO dispersion with a surface area of about 2.3X10 -4 m 2 Placing the alumina carrier in a suction filtration device, keeping the surface level of the carrier, adding deionized water without overload surface, starting a vacuum pump, removing liquid level impurities or bubbles after the vacuum pump pressure reaches-0.1 MPa and is stable, dropwise adding 0.4g of GO dispersion liquid after the liquid level 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 an LTL type molecular sieve grain layer: the surface area is about 2.3X10 -4 m 2 The GO modified alumina carrier is arranged in a suction filtration device for protectingMaintaining the surface level of the carrier, adding deionized water without overload surface, starting a vacuum pump, removing liquid level impurities or bubbles after the vacuum pump pressure reaches-0.1 MPa and is stable, dropwise adding 0.076g modified LTL type molecular sieve suspension after the liquid level 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: al is added with 2 (SO 4 ) 3 ·18H 2 O and KOH are dissolved in deionized water, stirred for 3 hours to obtain solution A, silicon source Ludox-As-40 is dissolved in deionized water, solution B is obtained by hydrolysis, and solution A is slowly dripped into solution B to obtain Al 2 O 3 、K 2 O、SiO 2 And H 2 The molar ratio of O is 1:10:20:300, and 0.5mL of the secondary synthetic solution is coated on 3.8X10 by using a spin coater under the condition of 2000r/min of rotating speed -4 And g, placing the surface of the crystal grain layer of the LTL type molecular sieve in a space-limited steam conversion reactor for 40 seconds, adding 0.04g of deionized water, sealing the reactor, and heating at 180 ℃ for reaction for 48 hours to obtain the LTL type molecular sieve membrane.
Characterization of the LTL type molecular sieve crystal grains prepared in the step (1) is carried out, and the result is shown in figure 1. As can be seen from FIG. 1, the crystal grains of the LTL type molecular sieve are disc-shaped, have the diameter of about 1.5 mu m and the thickness of about 0.2 mu m, and the characteristic peaks of the LTL type molecular sieve appear between 3 DEG and 50 DEG according to the XRD pattern, so that the prepared product is the LTL type molecular sieve.
And (3) characterizing the GO modified vector prepared in the step (3), wherein the result is shown in figure 2. As can be seen from fig. 2, the surface of the unmodified alumina carrier has large pores and depressions, and after the modification of GO, GO completely covers the surface of alumina, so that defects existing on the surface of the alumina carrier are modified; the XRD pattern shows that a peak of GO appears between 10 and 15 degrees, which indicates that GO does not change chemically in the modification process; according to a Raman spectrum, the alumina carrier modified by the GO has a D peak and a G peak with basically equal heights, which indicates that the GO membrane structure after suction filtration and assembly is more regular.
Characterization is carried out on the LTL type molecular sieve grain layer prepared in the step (4), and the result is shown in figure 3. As can be seen from FIG. 3, the LTL type molecular sieve assembled by suction filtration has crystal grains orderly arranged on the carrier, and the diffraction peaks of (001) and (002) crystal faces in the XRD pattern are strong, which indicates that the crystal grain layer is in c-axis orientation.
Characterization of the LTL-type molecular sieve membrane obtained in the step (5) is carried out, and the results are shown in FIG. 4 and FIG. 6. As can be seen from FIG. 4, the LTL type molecular sieve membrane prepared has compact surface without large defects, and the cross section is clear, and the thickness of the membrane layer is about 2 mu m. As shown in FIG. 6, the XRD pattern shows characteristic peaks of LTL type molecular sieve at 3-50 deg. and characteristic peaks of (001), (002), (004) crystal faces are strong, which means that the film has c-axis orientation.
LTL molecular sieve membrane gas permeation separation performance test:
the LTL-type molecular sieve membrane prepared in example 1 was subjected to single component H at normal temperature 2 、CO 2 Testing the gas permeation separation performance, testing the compactness of the film layer and testing the density of H 2 /CO 2 The results are shown in FIG. 7. As can be seen from FIG. 7, as the test gas pressure increases, H 2 、CO 2 The permeation flux of (C) is continuously increased, and H is at 0.1MPa 2 Is 9.0X10 - 8 mol·m -2 ·Pa -1 ·s -1 ，CO 2 Is 1.07×10 -9 mol·m -2 ·Pa -1 ·s -1 At this time, the ideal selectivity is as high as 84, the diffusion coefficient of Yu Nusen is 4.7, the film is compact and defect-free, and the film has high diffusion coefficient to H 2 /CO 2 Has 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 steps of referring to example 1, and is different from example 1 in that the heating reaction in step (5) is heating reaction at 180 ℃ for 72h.
The LTL-type molecular sieve membrane thus produced was characterized and the results are shown in fig. 5 and 6. As can be seen from FIG. 5, the LTL type molecular sieve membrane prepared has compact surface without large defects, and the cross section is clear, and the thickness of the membrane layer is about 600nm. As shown in FIG. 6, the XRD pattern shows characteristic peaks of LTL type molecular sieve at 3-50 deg. and characteristic peaks of (001), (002), (004) crystal faces are strong, which means that the film has c-axis orientation.
LTL molecular sieve membrane gas permeation separation performance test:
the LTL-type molecular sieve membrane prepared in example 2 was subjected to single component H at normal temperature 2 、CO 2 Testing the gas permeation separation performance, testing the compactness of the film layer and testing the density of H 2 /CO 2 The results are shown in FIG. 8. As can be seen from FIG. 8, as the test gas pressure increases, H 2 、CO 2 The permeation flux of (C) is continuously increased, and at 0.05MPa, H 2 Is 1.39X10 -6 mol·m -2 ·Pa -1 ·s -1 ，CO 2 Is 7.78X10 -8 mol·m -2 ·Pa -1 ·s -1 Its ideal selectivity can be up to 17.9, its high Yu Nusen diffusion coefficient is 4.7, and it is proved that said film is compact, has no defect, and has no defect to H 2 /CO 2 Has better selectivity.
The foregoing is merely a preferred embodiment of the present invention and it should be noted that modifications and adaptations to those skilled in the art may be made without departing from the principles of the present invention, which are intended to be comprehended within the scope of the present invention.
Claims (5)
1. A method for preparing an LTL type molecular sieve membrane by a space-limited steam conversion method, which is characterized by comprising the following steps:
(1) Preparation of LTL type molecular sieve crystal grains: mixing an aluminum source, an alkali source, a silicon source and deionized water, and performing hydrothermal crystallization to obtain LTL type molecular sieve grains;
(2) Modification of LTL type molecular sieve crystal grains: mixing LTL type molecular sieve crystal grains with hydrochloric acid solution, reacting for 0.5-2 h, washing to neutrality, then ultrasonically dispersing into sec-butyl alcohol solution, and stirring to obtain 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 an LTL type molecular sieve grain layer: assembling the modified LTL type molecular sieve suspension in the step (2) on the surface of the GO modified carrier 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: mixing an aluminum source, an alkali source, a silicon source and deionized water to prepare a secondary synthetic solution, coating the secondary synthetic solution on the surface of an LTL molecular sieve grain layer by adopting a spin coating method, placing the secondary synthetic solution in a space-limited steam conversion reactor, adding deionized water, sealing, and heating for reaction to obtain an LTL molecular sieve membrane;
wherein in the step (1), an aluminum source, an alkali source, a silicon source and deionized water are respectively prepared by Al 2 O 3 、K 2 O、SiO 2 And H 2 O represents, the Al 2 O 3 、K 2 O、SiO 2 And H 2 The molar ratio of O is 1: 7-10: 20-25: 300-800;
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 without overload surface, 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;
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 without overload surface, starting a vacuum pump, dropwise adding modified LTL type molecular sieve suspension, standing for 1-10 min after the deionized water is completely settled, and closing the vacuum pump;
the mass ratio of the area of the GO modified carrier to the mass ratio of the modified LTL type molecular sieve suspension in the step (4) is 1-5: 900-1200 m 2 /g；
The aluminum source, the alkali source, the silicon source and the deionized water of the secondary synthetic solution in the step (5) are respectively prepared by Al 2 O 3 、K 2 O、SiO 2 And H 2 O represents, the Al 2 O 3 、K 2 O、SiO 2 And H 2 The molar ratio of O is 1: 7-10: 20-25: 300-800;
the heating reaction temperature in the step (5) is 180-200 ℃ and the heating reaction time is 48-72 h.
2. The method for preparing an LTL-type molecular sieve membrane by a space-limited steam reforming process according to claim 1, wherein the mass ratio of LTL-type molecular sieve grains to the volume ratio of hydrochloric acid solution in step (2) is 1g: 15-30 mL; the mass concentration of the modified LTL type molecular sieve suspension is 0.5-2 wt%.
3. The method for preparing LTL-type molecular sieve membrane by space-limited steam reforming according to claim 1, wherein the carrier in step (3) is alumina, silica or zirconia.
4. The method for preparing the LTL type molecular sieve membrane by the space-limited steam conversion method according to claim 1, wherein the rotation speed of the spin coating of the secondary synthetic liquid in the step (5) is 2000-3000 r/min, and the spin coating time is 30-60 s.
5. The method for preparing LTL-type molecular sieve membrane by space-limited steam reforming according to claim 1 or 4, wherein the space-limited steam reforming reactor in step (5) has a polytetrafluoroethylene inner liner and a stainless steel outer liner, and the inner liner has a sealing cover.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110536606.7A CN113230907B (en) | 2021-05-17 | 2021-05-17 | Method for preparing LTL type molecular sieve membrane by space-limited steam conversion method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110536606.7A CN113230907B (en) | 2021-05-17 | 2021-05-17 | Method for preparing LTL type molecular sieve membrane by space-limited steam conversion method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113230907A CN113230907A (en) | 2021-08-10 |
| CN113230907B true CN113230907B (en) | 2023-04-28 |
Family
ID=77135002
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110536606.7A Active CN113230907B (en) | 2021-05-17 | 2021-05-17 | Method for preparing LTL type molecular sieve membrane by space-limited steam conversion method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113230907B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| 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 |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| 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 |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102015005732A1 (en) * | 2015-05-07 | 2016-11-10 | Forschungszentrum Jülich GmbH | Carbon-containing membrane for water and gas separation |
| CN105727757B (en) * | 2016-03-18 | 2019-12-24 | 宁夏大学 | Preparation method of oriented LTL type molecular sieve membrane for gas separation |
| CN109956464B (en) * | 2018-08-07 | 2022-03-15 | 江苏九天高科技股份有限公司 | NaA molecular sieve membrane, preparation method and application thereof |
| CN112426891B (en) * | 2020-10-09 | 2022-05-13 | 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 (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| 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 |
Also Published As
| Publication number | Publication date |
|---|---|
| CN113230907A (en) | 2021-08-10 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Xu et al. | Synthesis of a high‐permeance NaA zeolite membrane by microwave heating | |
| CN111249918B (en) | In-situ controllable synthesis method of MOF (Metal-organic framework) membrane | |
| CN102285666B (en) | Method for preparing chabazite and chabazite film | |
| CN107337472B (en) | Preparation method of FAU type zeolite molecular sieve membrane | |
| CN108465385B (en) | MAF-4 metal organic framework film and application thereof | |
| CN101254930B (en) | Method for synthesizing T-shaped zeolite membrane by microwave heating process | |
| CN103933871B (en) | A kind of preparation method of high stability all-silica MFI type molecular screen membrane | |
| CN101318665B (en) | Method for preparing high-performance Y type molecular sieve film and application of the same in organic mixture separation | |
| CN110683559A (en) | Green synthesis method of ultrathin SSZ-13 molecular sieve membrane | |
| WO2010110274A1 (en) | Zeolite membrane, separation membrane, and component separation method | |
| CN113230907B (en) | Method for preparing LTL type molecular sieve membrane by space-limited steam conversion method | |
| CN112121652B (en) | Preparation method of metal organic framework-ceramic membrane nanofiltration composite membrane | |
| CN111056560A (en) | Economic synthesis method of ultrathin SSZ-13 molecular sieve membrane | |
| CN112426895A (en) | Method for preparing hybrid silicon film by adopting POSS (polyhedral oligomeric silsesquioxane) doped structure and application of hybrid silicon film | |
| CN111298661A (en) | Preparation method and application of acid-resistant T-NaY zeolite molecular sieve composite membrane | |
| CN110152500B (en) | Separation membrane and preparation method and application thereof | |
| CN112705053B (en) | Preparation method and application of acid-resistant zeolite molecular sieve membrane | |
| CN101837989A (en) | Preparation method of fluorine-containing T-type zeolite membrane | |
| CN109761639B (en) | Nano porous aluminosilicate film material and preparation method thereof | |
| CN111137904A (en) | CHA type molecular sieve and synthesis method and application thereof | |
| CN108529639B (en) | Method for preparing chabazite membrane by crystal phase transformation | |
| CN114307689A (en) | Preparation method for synthesizing A-type zeolite membrane by wet gel conversion | |
| CN111943221A (en) | K-F type zeolite, preparation method thereof and application thereof in aldol condensation reaction | |
| CN105366689A (en) | Microwave-assisted method for synthesizing MOR zeolite molecular sieve membrane for dilute solution | |
| CN115417424B (en) | Swelling type silicon-aluminum ECNU-28 molecular sieve precursor and preparation method and application thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |