CN105561807B - Prepare method and the application of Woelm Alumina/zirconia composite carrier support Co IM mIM films - Google Patents

Abstract

The invention discloses a method and application for preparing a porous alumina/zirconia composite carrier supporting a Co-IM-mIM film; the preparation method is to prepare a layer of zirconia film on the surface of a macroporous alumina substrate, and then pass through a second Growth method generates Co‑IM‑mIM film on the surface of zirconia film layer, and the prepared porous alumina/zirconia composite support supports Co‑IM‑mIM film structure with dense, continuous and no surface defects; it is used for low-quality gas Separation and purification, not only has good separation effect, but also has good high temperature resistance, is stable at high temperature, does not crack, and maintains good separation performance at high temperature.

Description

Method for preparing porous alumina/zirconia composite carrier supporting Co-IM-mIM membrane and application

technical field

The invention relates to a method for preparing dense continuous porous metal-organic framework compound (MOFs) film on an alumina/zirconia composite porous support, and the porous alumina/zirconia composite support supports the Co-IM-mIM film at low The application in the purification of high-quality gas belongs to the technical field of new membrane materials.

Background technique

Due to the advantages of simple devices, low energy consumption and high separation efficiency, membrane separation technology has become one of the important industrial means. The use of membrane separation technology to purify low-quality gas has important practical significance for the application of low-quality gas. Many low-quality gases are prepared at high temperatures, so it is important to develop a molecular sieve membrane with excellent separation performance and high temperature resistance. actual meaning.

In the past ten years, metal-organic frameworks (MOFs) have attracted the attention of researchers due to their potential in gas separation and storage. Hundreds of metal-organic frameworks have been synthesized, and this The numbers are still increasing. Due to the diverse pore structures and void sizes of metal-organic framework compounds, as well as certain specific adsorption affinities, metal-organic framework compounds are excellent choices for the preparation of molecular sieve membranes.

Due to the structural characteristics of MOFs, the preparation of MOFs materials into molecular sieve membranes has aroused widespread interest among researchers. Many types of MOFs membranes have been developed, but due to the low adhesion of MOFs materials and the tendency to crack at high temperatures However, it is still a challenge to prepare a uniform and defect-free MOFs membrane. The carrier has an important influence on the synthesis of compact and defect-free membranes, and finding a suitable carrier is crucial for the successful synthesis of membranes. So far, scientific researchers usually use alumina, copper mesh and other substrates as carriers, and have successfully prepared a small amount of MOFs material membranes, but few of them have been put into industrial production. The high cost and low temperature resistance have hindered their industrial use. important factor in the application.

If a dense, continuous, defect-free and high-temperature-resistant membrane can be developed, it will be of great significance for MOFs membranes to adapt to different industrial gas separation environments.

Contents of the invention

In view of the defects existing in the existing MOFs material membranes, an object of the present invention is to provide a method for supporting Co-IM-mIM membranes on a porous alumina/zirconia composite carrier with a dense structure, continuous and no surface defects.

Another object of the present invention is to provide the application of the porous alumina/zirconia composite carrier supporting the Co-IM-mIM membrane, which is used for the separation and purification of low-quality gas, which not only has a good separation effect, but also It has good high temperature resistance, is stable at high temperature, does not crack, and maintains good separation performance at high temperature.

In order to achieve the above-mentioned technical purpose, the present invention provides a method for preparing a porous alumina/zirconia composite support Co-IM-mIM membrane, the method comprising the following steps:

(1) The zirconia particles in the zirconia particle suspension are supported on a certain surface of the macroporous alumina carrier by the pulling method, after drying, they are calcined at a high temperature of 600-800°C, and the zirconia particles in the macroporous alumina substrate A zirconia film layer is formed on the surface, that is, a porous alumina/zirconia composite carrier;

(2) ultrasonically disperse divalent cobalt salt, imidazole and dimethylimidazole in an organic solvent, stir and react at 10-40°C for 6-12 hours, and separate by filtration to obtain metal-organic framework seed crystals;

(3) dispersing the metal-organic framework seed crystals in an organic solvent, and loading the metal-organic framework seed crystals on the surface of the zirconia film layer of the porous alumina/zirconia composite carrier by a pulling method;

(4) Fix the porous alumina/zirconia composite carrier after the seed crystal in the reaction kettle, add the mixed solution containing divalent cobalt salt, imidazole and dimethylimidazole, seal the reaction kettle, and place it at 100-140°C reacting, forming a Co-IM-mIM film on the surface of the zirconia film layer of the porous alumina/zirconia composite support, washing and drying to obtain the product.

In the technical solution of the present invention, a layer of zirconia layer with relatively small pores is formed on the surface of macroporous alumina for the first time. The zirconia layer and the alumina layer are well combined, and the surface is rich in micropores. On this basis, Planting seed crystals with smaller particles and more uniform particle size distribution on the zirconia layer can make the subsequent Co-IM-mIM film dense, smooth, and free of surface defects, which solves the problem of the inability to prepare continuous, uniform and dense films in the prior art. Technical challenges of Co-IM-mIM membranes.

In a preferred solution, the particle size of the zirconia particles is 100-500 nm. The zirconia particles with appropriate particle size are selected so that zirconia can be embedded in the pore system of macroporous alumina, and the bonding force between the two is enhanced.

In a preferred scheme, the molar ratio of divalent cobalt salt, imidazole and dimethylimidazole in (2) is 1:0.5-5:0.5-5. By choosing an appropriate synthesis ratio, it is beneficial to form a complex with a stable structure, and the crystal size can be appropriately adjusted to suit the seed crystal.

In the preferred scheme, the reaction conditions in the process of preparing seed crystals in (2) are 10-40° C. and stirring for 6-12 hours. By selecting an appropriate reaction temperature and time, it is beneficial to form crystals with smaller particles and uniform particles. Seed to suit the seed crystal. The particle size of metal organic framework seed crystals can be controlled to be 0.5-5 μm.

In a preferred scheme, the calcination time in (1) is 1 to 5 hours.

In a preferred scheme, the reaction time in (4) is 6 to 48 hours.

In a preferred scheme, the molar ratio of divalent cobalt salt, imidazole and dimethylimidazole in the solution containing divalent cobalt salt, imidazole and dimethylimidazole in (4) is 1:0.5-5:0.5-5.

In a preferred solution, the metal-organic framework seed crystals in (3) are dispersed in an organic solvent so that the mass percent concentration of the metal-organic framework seed crystals reaches 1% to 5%.

The preferred scheme, the pulling method in (3), the number of times of pulling is 2 to 5 times, and the time to keep the porous alumina/zirconia composite carrier in the solution is 5 to 30 seconds during each pulling, and each time After the pulling is completed, the porous alumina/zirconia composite carrier is dried before the next pulling.

In a preferred solution, the surface pore diameter of the alumina matrix of the porous alumina/zirconia composite carrier is 1-5 microns, and the surface pore diameter of the zirconia coating is 0.1-0.5 microns.

The invention also provides the application of the porous alumina/zirconia composite carrier supporting the Co-IM-mIM membrane, which can be applied to the purification of low-quality gas.

The porous alumina/zirconia composite carrier used in the present invention is in the shape of sheet or hollow fiber.

The technical solution of the present invention is that the porous alumina/zirconia composite carrier supports the Co-IM-mIM membrane, which has a good separation effect on low-quality gas, and can selectively purify _H2 and _CH4 .

In a preferred solution, the separation of N ₂ and CO ₂ from H ₂ and CH ₄ is realized from low-quality gas containing H ₂ , N ₂ , CO ₂ and CH ₄ under a temperature environment of 15-100°C. The porous alumina/zirconia composite support Co-IM-mIM membrane has good high temperature resistance effect, not only stable at high temperature, no cracking, but also maintains good separation performance at high temperature.

Compared with the prior art, the beneficial technical effect brought by the technical solution of the present invention:

1. The technical solution of the present invention solves the problem that the prior art cannot prepare a continuous, uniform and dense Co-IM-mIM film; for the first time, a microporous zirconia film layer is introduced on the surface of macroporous alumina, and then seeded, Membrane production, can obtain continuous flat, high-density Co-IM-mIM membrane;

2. The film-making process proposed by the technical solution of the present invention is simple and efficient, and has good application prospects;

3. The porous alumina/zirconia composite support Co-IM-mIM membrane prepared by the technical solution of the present invention can effectively convert H ₂ and CH ₄ from low-quality components composed of H ₂ , N ₂ , CO ₂ and CH ₄ Separation and purification of gas, the membrane can maintain good separation performance at different separation ambient temperatures, has good thermal stability, overcomes the high temperature cracking of Co-IM-mIM membranes in the prior art, and the separation at high temperatures The defects with poor effect broaden the application field of Co-IM-mIM film.

Description of drawings

[Figure 1] (a) is the XRD pattern of CO-IM-mIM crystals prepared at room temperature; (b) is the XRD pattern of CO-IM-mIM crystals prepared at 120°C.

[ FIG. 2 ] is an SEM image of the zirconia film prepared in Example 1.

[ FIG. 3 ] is the SEM image of the CO-IM-mIM seed crystal prepared in Example 1.

[Figure 4] is the SEM image of the Co-IM-mIM membrane supported by the porous alumina/zirconia composite carrier prepared in Example 1.

[Figure 5] is the SEM image of the Co-IM-mIM film supported by the porous alumina/zirconia composite carrier prepared in Example 2.

[ FIG. 6 ] is the SEM image of the porous alumina carrier supported CO-IM-mIM film prepared in Comparative Example 1.

[ FIG. 7 ] is the SEM image of the CO-IM-mIM seed crystal prepared in Comparative Example 2.

[ FIG. 8 ] is the SEM image of the porous alumina/zirconia composite carrier supporting the CO-IM-mIM membrane prepared in Comparative Example 2.

Example 1

Zirconia particles with a particle size distribution of 20-500n were added to a stabilizer to form an acetone suspension with a mass content of 4wt%, and the zirconia was introduced into the porous alumina carrier by the pulling method, and the pulling time was 30s. After being dried under high temperature, put it into a muffle furnace at 600°C and bake for 4 hours to obtain a porous alumina/zirconia composite carrier;

Dissolve 2.32g of metal salt cobalt nitrate, 2.6g of dimethylimidazole, and 2g of imidazole in 350ml of methanol, stir and react at 25°C for 12 hours, and separate by filtration to obtain metal organic framework CO-IM-mIM seed crystals;

The porous alumina/zirconia composite carrier was seeded by pulling method in 4wt% CO-IM-mIM methanol solution, the number of pulling was 4 times, and the time of keeping the carrier in the seed liquid was 30 seconds during each pulling , after each pulling, the carrier is dried at 60°C for 6 hours before the next pulling;

Dissolve 0.58g of metal salt cobalt nitrate, o.65g of dimethylimidazole, and 0.5g of imidazole in 80ml of methanol, and ultrasonically dissolve it for 10 minutes. Take the seeded carrier and place it vertically in the reactor, add 80 ml of the prepared mother liquor into the reactor, seal it, put the reactor into a vacuum drying oven at 120°C for 24 hours. Then, the prepared Co-IM-mIM film taken out of the reactor was soaked in 100 ml of methanol for 4 hours, and finally dried at 80 °C for 6 hours to obtain the obtained film.

Normal temperature gas test: Put the prepared Co-IM-mIM membrane into a gas permeation device for gas separation test. Before the test, it is purged with He gas, and then ventilated with test gas for 10 minutes. During the test, the pressure at both ends of the membrane is maintained. The difference is 60KPa, and the test result is that the permeation amount of H ₂ is 16.96×10 ^-6 mol·m ^-2 ·s ^-1 ·Pa ^-1 , H ₂ /CO ₂ , H ₂ /N ₂ and H ₂ /CH ₄ The separation factors were 6.84, 5.37, 3.8, respectively.

Gas separation test at different temperatures: put the prepared Co-IM-mIM membrane into a self-made gas separator, then put the entire gas separator into a muffle furnace, place the gas pipeline in a constant temperature water tank, And keep the temperature of the muffle furnace and the constant temperature tank constant, change the temperature of the muffle furnace and the constant temperature water tank, test the gas separation performance at different temperatures, the test results are:

At 25°C: the permeation of H ₂ is 16.96×10 ^-6 mol·m ^-2 ·s ^-1 ·Pa ^-1 , the separation factors of H ₂ /CO ₂ , H ₂ /N ₂ and d H ₂ /CH ₄ They are 6.84, 5.37, 3.8 respectively.

At 40°C: H ₂ penetration is 16.71×10 ^-6 mol·m ^-2 s ^-1 ·Pa ^-1 , separation factors of H ₂ /CO ₂ , H ₂ /N ₂ and d H ₂ /CH ₄ They are 6.43, 5.37, 3.84 respectively.

At 55°C: H ₂ penetration is 16.34×10 ^-6 mol·m ^-2 s ^-1 ·Pa ^-1 , separation factors of H ₂ /CO ₂ , H ₂ /N ₂ and d H ₂ /CH ₄ They are 5.96, 5.45, 3.89 respectively.

At 70°C: H ₂ penetration is 16.19×10 ^-6 mol·m ^-2 s ^-1 ·Pa ^-1 , separation factors of H ₂ /CO ₂ , H ₂ /N ₂ and d H ₂ /CH ₄ They are 5.58, 5.43, 3.92 respectively.

At 90°C: H ₂ penetration is 15.98×10 ^-6 mol·m ^-2 s ^-1 ·Pa ^-1 , separation factors of H ₂ /CO ₂ , H ₂ /N ₂ and d H ₂ /CH ₄ They are 5.23, 5.49, 3.98 respectively.

Example 2

Zirconia particles with a particle size distribution of 20-500n were added with a stabilizer to form an acetone suspension with a mass content of 4wt%, and the zirconia was introduced into the porous alumina carrier by the pulling method, and the pulling time was 30s. After being dried under high temperature, put it into a muffle furnace at 600°C and bake for 4 hours to obtain a porous alumina/zirconia composite carrier;

Dissolve 2.32g of metal salt cobalt nitrate, 2.6g of dimethylimidazole, and 2g of imidazole in 350ml of methanol, stir and react at 25°C for 12 hours, and separate by filtration to obtain metal organic framework CO-IM-mIM seed crystals;

The porous alumina/zirconia composite carrier is seeded by pulling method in 2wt% CO-IM-mIM methanol solution, the number of pulling is 4 times, and the time of keeping the carrier in the seed liquid is 30 seconds during each pulling , after each pulling, the carrier is dried at 60°C for 6 hours before the next pulling;

Dissolve 0.58g of metal salt cobalt nitrate, o.65g of dimethylimidazole, and 0.5g of imidazole in 80ml of methanol, and ultrasonically dissolve it for 10 minutes. Take the seeded carrier and place it vertically in the reactor, add 80 ml of the prepared mother liquor into the reactor, seal it, put the reactor into a vacuum drying oven at 120° C. for 12 hours. Then put the prepared Co-IM-mIM membrane taken out from the reaction kettle into 100 ml of methanol and soak for 4 hours, and finally dry it at 80° C. for 6 hours to obtain the obtained film.

Normal temperature gas test: Put the prepared Co-IM-mIM membrane into a gas permeation device for gas separation test. Before the test, it is purged with He gas, and then ventilated with test gas for 10 minutes. During the test, the pressure at both ends of the membrane is maintained. The difference is 60KPa, and the test result is that the permeation amount of H ₂ is 17.37×10 ^-6 mol·m ^-2 ·s ^-1 ·Pa ^-1 , H ₂ /CO ₂ , H ₂ /N ₂ and H ₂ /CH ₄ The separation factors were 6.95, 5.25, 3.69, respectively.

Comparative Example 1

2.32g of metal salt cobalt nitrate, 2.6g of dimethylimidazole, and 2g of imidazole were ultrasonically dissolved in 350ml of methanol, stirred and reacted at 25°C for 12 hours, and separated by filtration to obtain metal organic framework CO-IM-mIM seed crystals;

The porous alumina carrier was seeded by pulling method in 4wt%CO-IM-mIM methanol solution, the number of times of pulling was 4 times, and the time of keeping the carrier in the seed liquid was 30 seconds when pulling each time. After the pulling is completed, the carrier is dried at 60°C for 6 hours before the next pulling;

Dissolve 0.58g of metal salt cobalt nitrate, o.65g of dimethylimidazole, and 0.5g of imidazole in 80ml of methanol, and ultrasonically dissolve it for 10 minutes. Take the seeded carrier and place it vertically in the reactor, add 80 ml of the prepared mother liquor into the reactor, seal it, put the reactor into a vacuum drying oven at 120°C for 24 hours. Then put the prepared Co-IM-mIM membrane taken out from the reaction kettle into 100 ml of methanol and soak for 4 hours, and finally dry it at 80° C. for 6 hours to obtain the obtained film.

It can be seen from the SEM image of the membrane that a continuous and defect-free Co-IM-mIM membrane cannot be directly synthesized through this macroporous alumina support.

Comparative Example 2

Zirconia particles with a particle size distribution of 20-500n were added with a stabilizer to form an acetone suspension with a mass content of 4wt%, and the zirconia was introduced into the porous alumina carrier by the pulling method, and the pulling time was 30s. After being dried under high temperature, put it into a muffle furnace at 600°C and bake for 4 hours to obtain a porous alumina/zirconia composite carrier;

Dissolve 2.32g metal salt cobalt nitrate, 2.6g dimethylimidazole, and 2g imidazole ultrasonically in 350ml of methanol, put the prepared organic solvent into the reaction kettle, then place the reaction kettle at 120°C for 24h, filter After separation and drying, the metal-organic framework seed crystals are obtained;

The porous alumina carrier was seeded by pulling method in 4wt%CO-IM-mIM methanol solution, the number of times of pulling was 4 times, and the time of keeping the carrier in the seed liquid was 30 seconds when pulling each time. After the pulling is completed, the carrier is dried at 60°C for 6 hours before the next pulling;

Dissolve 0.58g of metal salt cobalt nitrate, o.65g of dimethylimidazole, and 0.5g of imidazole in 80ml of methanol, and ultrasonically dissolve it for 10 minutes. Take the seeded carrier and place it vertically in the reactor, add 80 ml of the prepared mother liquor into the reactor, seal it, put the reactor into a vacuum drying oven at 120°C for 24 hours. Then put the prepared Co-IM-mIM membrane taken out from the reaction kettle into 100 ml of methanol and soak for 4 hours, and finally dry it at 80° C. for 6 hours to obtain the obtained film.

It can be seen from the SEM image of the film that the surface of the Co-IM-mIM film synthesized by this method is uneven and discontinuous, and the large grain crystals are aggregated together.

Claims (10)

1. prepare the method for Woelm Alumina/zirconia composite carrier support Co-IM-mIM films, it is characterised in that：Including following Step：

(1) zirconia particles in zirconia particles suspension are supported on to a certain table of macropore alumina supporter by czochralski method Face, after drying, it is placed under 600~800 DEG C of high temperature and is calcined, zirconium oxide film layer is formed on the surface of macroporous aluminium oxide matrix, Produce Woelm Alumina/zirconia composite carrier；

(2) by divalent cobalt, imidazoles and methylimidazole ultrasonic disperse in organic solvent, 10~40 DEG C of stirring reactions 6~ 12 hours, it is separated by filtration, obtains metal organic framework crystal seed；

(3) it is metal organic framework crystal seed is scattered in organic solvent, metal organic framework crystal seed is supported on by czochralski method The zirconium oxide film layer surface of Woelm Alumina/zirconia composite carrier；

(4) Woelm Alumina after kind of crystal seed/zirconia composite carrier is fixed in a kettle, added containing divalent cobalt, miaow The mixed solution of azoles and methylimidazole, reactor is sealed, is reacted at 100~140 DEG C, it is multiple in Woelm Alumina/zirconium oxide The zirconium oxide film layer surface for closing carrier forms Co-IM-mIM films, washs, and dries, produces.

2. the method according to claim 1 for preparing Woelm Alumina/zirconia composite carrier support Co-IM-mIM films, It is characterized in that：Described zirconia particles granularity is 100~500nm.

3. the method according to claim 1 for preparing Woelm Alumina/zirconia composite carrier support Co-IM-mIM films, It is characterized in that：(2) the addition mol ratio of divalent cobalt, imidazoles and methylimidazole in is 1:0.5~5:0.5~5；(4) In in the solution containing divalent cobalt, imidazoles and methylimidazole divalent cobalt, imidazoles and methylimidazole mol ratio be 1:0.5~ 5:0.5~5.

4. the method according to claim 1 for preparing Woelm Alumina/zirconia composite carrier support Co-IM-mIM films, It is characterized in that：(1) roasting time in is 1~5h；(4) reaction time in is 6~48 hours.

5. the method according to claim 1 for preparing Woelm Alumina/zirconia composite carrier support Co-IM-mIM films, It is characterized in that：Described metal organic framework seed particles granularity is 0.5~5 μm.

6. the method according to claim 1 for preparing Woelm Alumina/zirconia composite carrier support Co-IM-mIM films, It is characterized in that：(3) the scattered quality hundred for making metal organic framework crystal seed in organic solvent of metal organic framework crystal seed in Specific concentration is divided to reach 1%~5%.

7. the method according to claim 1 for preparing Woelm Alumina/zirconia composite carrier support Co-IM-mIM films, It is characterized in that：(3) czochralski method in, lifting number are 2~5 times, keep Woelm Alumina/zirconium oxide compound during lifting every time Residence time is 5~30 seconds to carrier in the solution, and every time after the completion of lifting, Woelm Alumina/zirconia composite carrier is entered Row drying, then lifted next time.

8. prepare Woelm Alumina/zirconia composite carrier support Co-IM-mIM according to any one of claim 1~7 The method of film, it is characterised in that：The alumina substrate surface apertures of described Woelm Alumina/zirconia composite carrier are 1~5 Micron, zirconia coating surface apertures are 0.1~0.5 micron.

9. Woelm Alumina prepared by any one of claim 1~7 methods described/zirconia composite carrier support Co-IM-mIM The application of film, it is characterised in that：Purified applied to low-quality combustion gas.

10. the application of Woelm Alumina according to claim 9/zirconia composite carrier support Co-IM-mIM films, it is special Sign is：Under 15~100 DEG C of temperature environments, from including H₂、N₂、CO₂And CH₄Low-quality combustion gas in realize N₂And CO₂With H₂ And CH₄Separation.