A bimetallic MOR molecular sieve and its preparation method and application

Abstract

The invention provides a bimetallic MOR molecular sieve and a preparation method and application thereof, comprising the following steps: S1, mixing sodium hydroxide, sodium aluminate and deionized water, and stirring at room temperature for 0.5-3 hours at a rotation speed of 150-400 r / min to obtain a first mixed solution; S2, slowly dropping a silicon source into the first mixed solution, and stirring at a rotation speed of 150-400 r / min for 2-6 hours to obtain a second mixed solution; S3, adding an organic metal calcium compound and an organic metal titanium compound into the second mixed solution, and stirring at a rotation speed of 150-400 r / min for 10-15 hours to obtain a third mixed solution; the organic metal calcium compound is one or more of calcium 2-ketoglutarate, calcium citrate and calcium hexafluoroacetylacetonate; the organic metal titanium compound is one or more of titanium isopropionate, titanium acetylacetonate oxide and titanium tert-butoxide; S4, transferring the third mixed solution to a reactor, and obtaining a bimetallic MOR molecular sieve finished material through hydrothermal crystallization, washing, drying and roasting.

Description

Technical Field

[0001] The invention relates to the field of molecular sieves, and in particular to a bimetallic MOR molecular sieve and a preparation method and application thereof. Background Art

[0002] He has a wide range of applications in industry, especially in the semiconductor, liquid crystal display and optical fiber fields in high-end equipment manufacturing, followed by medical nuclear magnetic resonance imaging and low-temperature superconducting equipment, airtightness inspection of high-end equipment, preparation of superfluid materials and other fields. At present, the only source of commercial high-purity He is extracted from natural gas. After obtaining crude He with a molar fraction of 50-80% through deep-cold distillation process, it is necessary to further remove impurity gases such as CH4, O2, H2, Ar and Ne to obtain high-purity He. Among them, the content of Ne in the small amount of mixed impurity gas in the high-purity He gas with a purity of 6N is less than 1 ppb. Because the physical and chemical properties of Ne are extremely similar to those of He, such as boiling point (He: 4.3 K; Ne: 27.07 K), kinetic diameter (He: 2.55 Å; Ne: 2.82Å) and polarity (He: 2.05 × 10 25 / cm 3 ; Ne: 3.96 × 10 25 / cm 3 ), therefore, the separation of Ne and He is relatively difficult.

[0003] In addition, as a bulk electronic gas, high-purity N2 plays a key role in many fields, especially in the electronics industry, where high-purity N2, as a protective gas and carrier gas, is essential for the production and maintenance of integrated circuits and semiconductor devices. In addition, in experimental research and the pharmaceutical industry, high-purity N2 is used to maintain an oxygen-free environment, sample protection, and experimental condition control. At the same time, it is also used as a refrigerant, tire filling gas, etc. Due to its inertness and stability, high-purity N2 plays an indispensable role in ensuring production efficiency, product quality, and safety in various fields. Commercial-grade high-purity N2 is mainly obtained by air separation, a process that involves removing moisture, CO2, and O2 from the air to obtain crude N2. However, the air contains about 18 ppm of Ne, which is very similar to N2 in physical and chemical properties (boiling point of N2: 77.35 K; kinetic diameter: 3.64–3.80 Å; polarity: 17.403 × 10 25 / cm 3 ), which makes it extremely difficult to separate the lower concentration Ne from N2.

[0004] At present, there are few studies on the separation of Ne and He and the separation of low-concentration Ne from N2 in China.

[0005] Domestically, Ne and He are mainly separated by cryogenic processes. For example, Chinese patent CN201210061205.1 discloses a Ne / He separation and purification method, which pressurizes Ne / He mixed gas to 170~200 bar, and cools it to 25~35 K in multiple steps to separate gas and liquid to obtain crude He. After the crude He is cooled to 60~70 K, it enters a low-temperature adsorber to remove impurities to obtain pure He (the volume fraction of He gas prepared by this method is greater than 99.999%). However, the energy consumption of separation and purification using this cryogenic process is very large, the production cost is relatively high, and it is not conducive to industrial production.

[0006] At present, the domestic industry mainly uses cryogenic process to remove low concentration Ne in N2 to obtain higher purity N2. Chinese patent CN201510619367.6 discloses a method for removing Ne from N2, which is carried out in a vacuum insulation container using cryogenic process, with an operating pressure of 15~20 KPa and an operating temperature of 65~70 K. Since the physical properties of N2 and Ne, such as boiling points, are extremely close, the cryogenic process to remove Ne from N2 is a relatively difficult and energy-intensive process, and therefore, is not conducive to industrial production.

[0007] At present, foreign countries have adopted non-cryogenic processes to improve the separation of Ne and He, but the existing molecular sieves still cannot achieve a good separation effect. For example, US Patent US3854913 A discloses a method for extracting high-purity He from Ne / He mixed gas. The key to this method is to perform continuous condensation at the triple point of Ne (24.5561 K) and ensure that the operating pressure is maintained at 25 atm. Subsequently, in the temperature range below the triple point (5.2~22 K), the molecular sieve is used to adsorb Ne, thereby effectively preparing high-purity He from the mixed gas (the volume fraction of He gas prepared by this method is greater than 98%); although this method adopts the molecular sieve adsorption scheme, it still needs to be carried out at a lower temperature, and it still involves the problem of maintaining a low temperature and causing huge energy consumption, and the purity of He is difficult to further improve. In addition, this process is suitable for the separation of Ne and He, but it cannot achieve good Ne / N2 separation, especially the separation of low-concentration Ne in N2. In addition to the high-energy-consuming cryogenic process, there are still no other technical breakthroughs.

[0008] Therefore, how to develop an efficient adsorbent that preferentially adsorbs Ne for the preparation of high-purity N2 and high-purity He has always been an urgent problem to be solved by technicians in this field. Summary of the invention

[0009] Based on this, it is necessary to provide a bimetallic MOR molecular sieve and a preparation method and application thereof.

[0010] In order to solve the above technical problems, the present invention provides a method for preparing a bimetallic MOR molecular sieve, comprising the following steps:

[0011] S1, mixing sodium hydroxide, sodium aluminate and deionized water, and stirring at room temperature for 0.5-3 hours at a speed of 150-400 r / min to obtain a first mixed solution;

[0012] S2, slowly adding the silicon source dropwise to the first mixed solution, stirring at a speed of 150-400 r / min for 2-6 hours to obtain a second mixed solution;

[0013] S3, adding the organometallic calcium compound and the organometallic titanium compound to the second mixed solution, stirring at a speed of 150-400 r / min for 10-15 hours to obtain a third mixed solution;

[0014] Wherein, the organic metal calcium compound is one or more of calcium 2-ketoglutarate, calcium citrate and calcium hexafluoroacetylacetonate; the organic metal titanium compound is one or more of titanium isopropionate, titanium acetylacetonate oxide and titanium tert-butoxide;

[0015] S4. The third mixed solution is transferred to a reactor, and a bimetallic MOR molecular sieve finished product is obtained through hydrothermal crystallization, washing, drying and calcination.

[0016] Preferably, in the third mixed solution, the molar ratio of the silicon source, sodium hydroxide, sodium aluminate, deionized water, organic metal calcium compound and organic metal titanium compound is 1:0.35:0.1:18:(0.0005-0.005):(0.0001-0.001).

[0017] Preferably, in step S1, stirring is performed at room temperature at a rotation speed of 200-350 r / min for 1 hour.

[0018] Preferably, the silicon source is one or more combinations of silica sol or tetraethyl orthosilicate.

[0019] Preferably, in step S2, stirring is performed at a rotation speed of 200-350 r / min for 4 hours.

[0020] Preferably, in step S3, stirring is performed at a speed of 200-350 r / min for 12 hours.

[0021] Preferably, the organic metal calcium compound is calcium 2-ketoglutarate, and the organic metal titanium compound is titanium isopropionate.

[0022] Preferably, in S4, the hydrothermal crystallization conditions are: temperature of 170-180°C, time of 48-90 hours; the washing refers to washing the product with deionized water to neutrality, and the drying refers to drying at 100-120°C for 8-12 hours; the calcination conditions are: calcination at 450-550°C for 4-6 hours, and the heating rate is 6°C / min.

[0023] The present invention also provides a bimetallic MOR molecular sieve, which is prepared using the preparation method.

[0024] The bimetallic MOR molecular sieve is used as an adsorbent to selectively separate Ne from a mixed gas, wherein the mixed gas is at least one of N2 and He.

[0025] The beneficial effects of the present invention are as follows: for mixed gases, especially mixed gases of N2 and He mixed with Ne, the bimetallic MOR molecular sieve of the present invention has the characteristics of preferentially adsorbing Ne and having a large adsorption capacity under specific temperature and pressure conditions, and at the same time, hardly adsorbing N2 and He; this selective adsorption characteristic enables the bimetallic MOR molecular sieve of the present invention to be used for the adsorption of trace amounts of Ne in high-purity N2 and He gases, thereby efficiently preparing high-purity He or N2, and preparing ultra-high purity N2 and He gases.

[0026] Compared with the extremely low temperature required for gas separation and purification in the prior art, the required temperature requirement of the present invention is equivalent to the boiling point of liquid nitrogen, which saves the energy consumption of reducing to extremely low temperature, greatly reduces the energy consumption of refrigeration, and achieves the purpose of high efficiency and energy saving. At the same time, the time required for the hydrothermal synthesis of the bimetallic MOR molecular sieve of the present invention is relatively short, which is much lower than the synthesis time of the existing loaded metal MOR series molecular sieves. This breakthrough in the reduction of synthesis time not only greatly improves the synthesis efficiency, but also significantly reduces energy consumption by reducing the reaction time, further strengthening the low energy consumption characteristics of the molecular sieve of the present invention used as an adsorbent in gas separation and purification, showing the dual advantages of the present invention in energy saving and efficient synthesis, thereby reducing the cost of production and gas separation and purification. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above and other purposes, features and advantages of the present invention will become more clear by more specific description of the preferred embodiments of the present invention shown in the accompanying drawings. The same reference numerals indicate the same parts in all the accompanying drawings, and the accompanying drawings are not deliberately scaled to the actual size, and the focus is on illustrating the main purpose of the present invention.

[0028] Figure 1 The XRD diagrams of the MOR zeolite molecular sieve products prepared in Examples 1 to 3 and Comparative Example 1;

[0029] Figure 2Single-component adsorption isotherms of neon, nitrogen and helium for the bimetallic MOR molecular sieve prepared in Example 1;

[0030] Figure 3 Single component adsorption isotherms of neon, nitrogen and helium for the bimetallic MOR molecular sieve prepared in Example 2;

[0031] Figure 4 Single component adsorption isotherms of neon, nitrogen and helium for the bimetallic MOR molecular sieve prepared in Example 3;

[0032] Figure 5 Single-component adsorption isotherms of neon, nitrogen and helium for the MOR molecular sieve prepared in Comparative Example 1;

[0033] Figure 6 The ideal adsorption solution theory (IAST) selectivity result diagram of the binary mixture of neon and nitrogen (Ne / N2) of the MOR molecular sieve prepared in Example 1 and Comparative Example 1;

[0034] Figure 7 This is a diagram showing the selectivity results of the ideal adsorption solution theory (IAST) of the binary mixture of neon and helium (Ne / He) of the MOR molecular sieves prepared in Example 1 and Comparative Example 1. DETAILED DESCRIPTION

[0035] To facilitate understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings.

[0036] The technical solution of the present invention is further described in detail below in conjunction with specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0037] The present invention provides a method for preparing a bimetallic MOR molecular sieve, comprising the following steps:

[0038] S1, mixing sodium hydroxide, sodium aluminate and deionized water, and stirring at room temperature for 0.5-3 hours at a speed of 150-400 r / min to obtain a first mixed solution;

[0039] S2, slowly adding the silicon source dropwise to the first mixed solution, stirring at a speed of 150-400 r / min for 2-6 hours to obtain a second mixed solution;

[0040] S3, adding the organometallic calcium compound and the organometallic titanium compound to the second mixed solution, stirring at a speed of 150-400 r / min for 10-15 hours to obtain a third mixed solution;

[0041] Wherein, the organic metal calcium compound is one or more of calcium 2-ketoglutarate, calcium citrate and calcium hexafluoroacetylacetonate; the organic metal titanium compound is one or more of titanium isopropionate, titanium acetylacetonate oxide and titanium tert-butoxide;

[0042] S4. The third mixed solution is transferred to a reactor, and a bimetallic MOR molecular sieve finished product is obtained through hydrothermal crystallization, washing, drying and calcination.

[0043] In view of the deficiencies in the prior art, the bimetallic MOR molecular sieve prepared by the present invention is prepared by a hydrothermal method by adding two organic ligand metals, and the bimetallic MOR molecular sieve is loaded with two metal ions of calcium and titanium, and the metal ions are not easily lost in the molecular sieve framework. In the case where the difference between the kinetic diameter of Ne and the kinetic diameter of He is small, the bimetallic MOR molecular sieve of the present invention can be used as a porous adsorbent, and the synergistic effect of the two metal ions of calcium and titanium is utilized to show excellent adsorption capacity for Ne with higher polarity. On the other hand, the molecular kinetic diameter of N2 is large, and it cannot enter the microporous channels of the MOR molecular sieve and is effectively excluded. Therefore, the molecular sieve can efficiently and preferentially adsorb trace amounts of Ne in N2 and He. The molecular sieve of the present application is used as a porous adsorbent, and while having a high Ne adsorption capacity, it also has a high separation selectivity of a binary mixed gas of Ne and N2 or Ne and He. The entire preparation process of the present invention is simple and easy to implement, and is suitable for industrial production. The Ne mentioned in the present invention is neon, N2 is nitrogen, and He is helium.

[0044] In a preferred embodiment, in the third mixed solution, the molar ratio of the silicon source, sodium hydroxide, sodium aluminate, deionized water, organic metal calcium compound and organic metal titanium compound is 1:0.35:0.1:18:(0.0005-0.005):(0.0001-0.001). More preferably, the molar ratio of the silicon source, sodium hydroxide, sodium aluminate, deionized water, organic metal calcium compound and organic metal titanium compound is: 1:0.35:0.1:18:0.001:0.0005. The bimetallic MOR molecular sieve prepared by suitable loading amount and using preferred organic metal compound for loading effectively improves the adsorption capacity and adsorption capacity of Ne.

[0045] In a preferred embodiment, in step S1, stirring is performed at room temperature at a rotation speed of 200-350 r / min for 1 hour.

[0046] In a preferred embodiment, the silicon source is one or more combinations of silica sol or tetraethyl orthosilicate. More preferably, the silicon source is tetraethyl orthosilicate.

[0047] In a preferred embodiment, in step S2, stirring is performed at a rotation speed of 200-350 r / min for 4 hours.

[0048] In a preferred embodiment, in step S3, stirring is performed at a speed of 200-350 r / min for 12 hours.

[0049] In a preferred embodiment, the organic metal calcium compound is calcium 2-ketoglutarate, and the organic metal titanium compound is titanium isopropionate.

[0050] In a preferred embodiment, in S4, the hydrothermal crystallization conditions are: temperature of 170-180°C, time of 48-90 hours; the washing means washing the product with deionized water to neutrality, the drying means drying at 100-120°C for 8-12 hours; the calcination conditions are: calcination at 450-550°C for 4-6 hours, and the heating rate is 6°C / min. The optimal hydrothermal crystallization conditions are: temperature of 170°C, time of 72 hours.

[0051] In the hydrothermal synthesis process of the bimetallic MOR molecular sieve of the present invention, the minimum time required for hydrothermal crystallization is only 48 hours. This breakthrough in shortening the synthesis time not only greatly improves the synthesis efficiency, but also significantly reduces energy consumption by shortening the reaction time, further strengthening the low energy consumption characteristics of using the molecular sieve of the present invention as an adsorbent in gas separation and purification, which is much lower than the synthesis time of more than 300 hours of the existing loaded metal MOR series molecular sieves. The present invention demonstrates the dual advantages of energy saving and efficient synthesis, thereby reducing the cost of making molecular sieves and gas separation and purification.

[0052] A bimetallic MOR molecular sieve is prepared using the preparation method. In view of the fact that existing molecular sieves need to add a binder during the molding process, the content of the added binder generally accounts for 30-40% of the total mass of the finished catalyst. Since the binder is generally an inert component, it will "dilute" the active center of the molecular sieve, making the actual reaction space velocity larger, leading to the problem of accelerated catalyst deactivation, and the binder has a certain pore blocking effect on the molecular sieve, which will affect the diffusion performance and further affect the gas adsorption performance. The bimetallic MOR molecular sieve prepared by the present invention directly obtains high-strength molded block particles by hydrothermal synthesis, which effectively solves the problem of pore blockage caused by the use of binders in the molding process of powder adsorbents, and also prevents the disadvantage of adsorption sites being diluted.

[0053] The bimetallic MOR molecular sieve is used as an adsorbent to selectively separate Ne in a mixed gas, wherein the mixed gas is at least one of N2 and He. The adsorbent prepared in the present application is a highly efficient adsorbent that can preferentially adsorb Ne in a mixed gas, and can be used to prepare high-purity N2 and high-purity He. It has high efficiency, low energy consumption, good separation and purification effect, simple operation and economic advantages. It has great potential in low-temperature adsorption and removal of trace Ne in N2 and He. The operating temperature of gas separation using the bimetallic MOR molecular sieve of the present invention as an adsorbent is significantly different from the temperature required for removing Ne from N2 and He using the existing cryogenic process. The bimetallic MOR molecular sieve of the present invention shows preferential adsorption of Ne under 77 K conditions, with an adsorption capacity of 1.27 mmol g-1 (1 bar), and almost no adsorption of N2 and He. The existing cryogenic process method uses a temperature of 5.2~25 K. Compared with the extremely low temperature required for separating and purifying gases in the prior art, which consumes a lot of energy, the temperature required by the present invention is equivalent to the boiling point of liquid nitrogen, which saves the energy consumption of lowering to an extremely low temperature, greatly reduces the energy consumption of refrigeration, and achieves the purpose of high efficiency and energy saving.

[0054] In order to have a further understanding and recognition of the technical solution of the present invention, several embodiments are listed to further illustrate it in detail.

[0055] Example 1

[0056] The independent preparation of bimetallic MOR molecular sieve includes the following steps:

[0057] Sodium hydroxide, sodium aluminate and deionized water were weighed and mixed in a polytetrafluoroethylene beaker, and stirred vigorously at a speed of 350 r / min to obtain a first mixed solution. After magnetic stirring for 1 hour, tetraethyl orthosilicate was slowly added dropwise to the first mixed solution, and stirred at 350 r / min. r / min speed condition, the second mixed solution was obtained by vigorous stirring; after magnetic stirring for 4 hours, calcium 2-ketoglutarate and titanium isopropionate were added to the second mixed solution, and the mixture was stirred to obtain a third mixed solution; in the third mixed solution, the molar ratio of silicon source, sodium hydroxide, sodium aluminate, deionized water, calcium 2-ketoglutarate and titanium isopropionate was 1:0.35:0.1:18:0.001:0.0005; after magnetic stirring for 12 hours, the third mixed solution was transferred to a reactor and hydrothermally crystallized at 170°C for 72 hours; after the end, the product was filtered and repeatedly washed with deionized water until neutral, and then dried in a drying oven at 120°C for 12 hours, and finally calcined at 550°C for 6 hours to obtain the bimetallic MOR molecular sieve A1.

[0058] Example 2

[0059] The independent preparation of bimetallic MOR molecular sieve includes the following steps:

[0060] Sodium hydroxide, sodium aluminate and deionized water were weighed and mixed in a polytetrafluoroethylene beaker, and the mixture was vigorously stirred at a speed of 200 r / min to obtain a first mixed solution; after magnetic stirring for 1 hour, ethyl orthosilicate was slowly added dropwise to the first mixed solution, and the mixture was vigorously stirred at a speed of 200 r / min to obtain a second mixed solution; after magnetic stirring for 4 hours, calcium citrate and titanium acetylacetonate were added to the second mixed solution, and the mixture was stirred to obtain a third mixed solution; in the third mixed solution, the molar ratio of silicon source, sodium hydroxide, sodium aluminate, deionized water, calcium citrate and titanium acetylacetonate was 1:0.35:0.1:18:0.0005:0.0001; after magnetic stirring for 12 hours, the third mixed solution was transferred to a reactor and hydrothermally crystallized at 170°C for 48 hours; after the reaction, the product was filtered and repeatedly washed with deionized water until neutral, and then dried in a drying oven at 100°C for 8 hours, and finally calcined at 450°C for 4 hours to obtain the bimetallic MOR molecular sieve A2.

[0061] Example 3

[0062] The independent preparation of bimetallic MOR molecular sieve includes the following steps:

[0063] Sodium hydroxide, sodium aluminate and deionized water were weighed and mixed in a polytetrafluoroethylene beaker, and stirred vigorously at a speed of 300 r / min to obtain a first mixed solution. After magnetic stirring for 1 hour, ethyl orthosilicate was slowly added dropwise to the first mixed solution, and stirred at 300 r / min. r / min speed condition, stir vigorously to obtain the second mixed solution; after magnetic stirring for 4 hours, add calcium hexafluoroacetylacetonate and titanium tert-butoxide to the second mixed solution, stir to obtain the third mixed solution; in the third mixed solution, the molar ratio of silicon source, sodium hydroxide, sodium aluminate, deionized water, calcium hexafluoroacetylacetonate and titanium tert-butoxide is 1:0.35:0.1:18:0.005:0.001; after magnetic stirring for 12 hours, transfer the third mixed solution to the reactor, and hydrothermally crystallize at 180°C for 90 hours; after completion, filter the product and wash it repeatedly with deionized water until it is neutral, and then dry it in a drying oven at 100°C for 10 hours, and finally calcine it at 500°C for 5 hours to obtain the bimetallic MOR molecular sieve A3.

[0064] Comparative Example 1

[0065] Compared with Example 1, in Comparative Example 1, no organometallic calcium compound and organometallic titanium compound were added, and the rest of the formula and preparation method were the same as those of Example 1, to prepare comparative MOR molecular sieve B1.

[0066] The pore parameters of the MOR molecular sieve product prepared in Example 1-3 were tested:

[0067] The pore structures of the products A1, A2 and A3 prepared in Examples 1-3 were characterized using an ASAP-2460 specific surface area pore size distribution analyzer from Micro Corporation of the United States. The pore parameters, specifically the BET specific surface area and total pore volume, were obtained by testing. The results are shown in Table 1.

[0068] Table 1 Pore parameters of products A1, A2 and A3 prepared in Examples 1-3

[0069]

[0070] The results of the performance tests in Table 1 are explained as follows:

[0071] The BET specific surface area of ​​the bimetallic MOR molecular sieve prepared by the present invention is 318-348 m 2 g -1 The total pore volume is between 0.169-0.184 cm 3 g -1 The results show that the MOR molecular sieves prepared in Examples 1-3 of the present invention have good pores, excellent gas adsorption capacity and pore space for gas storage.

[0072] The products A1, A2, A3 and B1 prepared in Examples 1-3 and Comparative Example 1 were subjected to XRD test, gas adsorption performance test and IAST selectivity theoretical calculation.

[0073] 1. XRD test

[0074] The products A1, A2, A3 and B1 prepared in Examples 1-3 and Comparative Example 1 were subjected to X-ray diffraction experiments: The products A1, A2, A3 and B1 prepared in Examples 1-3 and Comparative Example 1 were subjected to XRD tests using a D8 Advance X-ray diffractometer from Bruker, Germany. The results are as follows: Figure 1 shown.

[0075] Figure 1 The middle curves represent the XRD spectra of the products A1, A2, A3 and B1 prepared in Examples 1-3 and Comparative Example 1, respectively. By comparing with the XRD standard spectra of MOR molecular sieve, it can be known that the XRD curves of products A1, A2, A3 and B1 are consistent with the XRD standard spectra of MOR molecular sieve and are pure phases. This shows that the prepared products A1, A2, A3 and B1 have the crystal structure of MOR molecular sieve, thereby confirming that the prepared products are MOR molecular sieves.

[0076] At the same time, the XRD patterns of the bimetallic MOR molecular sieves loaded in Examples 1-3 are similar to those of the unloaded metal MOR molecular sieve in Comparative Example 1, and the main characteristic peak positions are the same, indicating that after the bimetallic MOR molecular sieve of the present invention is loaded with calcium and titanium metal ions, its crystal structure remains intact and no impurity peaks exist.

[0077] 2. Gas adsorption performance test:

[0078] (1) The gas adsorption performance of the products A1, A2, A3 and B1 prepared in Examples 1 to 3 and Comparative Example 1 was tested:

[0079] The products prepared in Examples 1 to 3 and Comparative Example 1 were heated at 200 o C vacuum degassing activation for 24 hours to remove the adsorbed moisture and impurity molecules in the product; using the American 3Flex vapor adsorption instrument (Micromeritics), using a liquid nitrogen cold trap to maintain the temperature at 77 K during the test process, the single component adsorption isotherms of the products A1, A2, A3 and B1 prepared in Examples 1-3 of the present invention and Comparative Example 1 at 77 K were measured respectively. The adsorption isotherms of neon, nitrogen and helium at 77 K were tested, as shown in FIG. Figure 2 , Figure 3 , Figure 4 and Figure 5 shown.

[0080] from Figure 2 It can be seen that under the low pressure condition of 0-0.1 bar, for the product A1 of Example 1, the Ne adsorption curve rises faster and the overall trend of the curve is steeper, indicating that the product A1 has a strong adsorption force for Ne; Figure 3 and Figure 4 It can be seen that under the low pressure zone of 0-0.1 bar, for the products A2 and A3 prepared in Examples 2 to 3, the Ne adsorption curves generally rise. Figure 3 and Figure 4 The overall trend of the curve in Figure 2 It is relatively gentle, indicating that the adsorption of Ne by products A2 and A3 is weaker than that of product A1. Figure 5 It can be seen that under the low pressure condition of 0-0.1 bar, for the product B1 prepared in Comparative Example 1, the Ne adsorption curve rises slowly. Figure 5 The overall trend of the curve in Figure 3 and Figure 4 It is even more gentle, indicating that the adsorption force of product B1 on Ne is weaker than that of products A2 and A3, and much weaker than that of product A1.

[0081] In summary, compared with the unloaded metal MOR molecular sieve in Comparative Example 1, the bimetallic MOR molecular sieves loaded in Examples 1 to 3 prepared in Examples 1 to 3 have better adsorption capacity and adsorption capacity for Ne than the unloaded metal MOR molecular sieve prepared in Comparative Example 1, indicating that the bimetallic MOR molecular sieves loaded with organic calcium compounds and organic titanium compounds can effectively improve the adsorption capacity and adsorption capacity for Ne.

[0082] The Ne adsorption capacity of the product of Example 1 is higher than that of the products of Examples 2 and 3. It can be seen that when the organometallic compound is loaded, the appropriate loading amount of the organometallic compound and the selection of the specific organometallic compound will also have a positive effect on the Ne adsorption capacity.

[0083] (2) Figure 2-5 In the table, the specific values ​​of the adsorption capacity of Ne for the products A1, A2, A3 and B1 prepared in Examples 1 to 3 and Comparative Example 1 under the conditions of 77 K and 1 bar and 77 K and 0.1 bar are respectively extracted and listed in Table 2:

[0084] Table 2 Adsorption capacities of products A1, A2, A3 and B1 for Ne, N2 and He at different pressures at 77 K

[0085]

[0086] In Table 2, at 77 K and 0.1 bar, the adsorption capacity of the product of Example 1 for neon is 0.59 mmolg -1 At 77 K and 1 bar, the adsorption capacity of the product of Example 1 for neon is 1.27 mmol g -1 The adsorption capacity for nitrogen and helium is 0.13 mmol g -1 and 0.06 mmol g -1 , indicating that product A1 has a strong adsorption capacity for Ne, and almost no adsorption for N2 and He. It can be seen that product A1 prepared in Example 1 has the excellent performance of preferentially adsorbing neon and having a large adsorption capacity;

[0087] At 77 K and 0.1 bar, the adsorption capacities of products A2 and A3 prepared in Examples 2 to 3 for neon were 0.49 mmol g -1 and 0.48 mmol g -1 At 77 K and 1 bar, the adsorption capacity of products A2 and A3 for neon is 1.08 mmol g -1 and 1.04 mmol g -1, indicating that the Ne adsorption performance of products A2 and A3 is not much different from that of Example 1, the adsorption capacity is slightly weaker, and they almost do not adsorb N2 and He.

[0088] Under the conditions of 77 K and 0.1 bar, the adsorption capacity of neon gas by the product B1 prepared in Comparative Example 1 was 0.31 mmol g -1 At 77 K and 1 bar, the adsorption capacity of product B1 for neon is 0.82 mmol g -1 Under the same conditions, the product B1 prepared in Comparative Example 1 has no bimetallic loading, so the adsorption of Ne by the prepared product B1 is significantly different from that of the products of Examples 1 to 3.

[0089] In summary, compared with the unloaded metal MOR molecular sieve in Comparative Example 1, the bimetallic MOR molecular sieves prepared in Examples 1 to 3 have better adsorption selectivity and adsorption capacity for Ne than the unloaded metal MOR molecular sieve prepared in Comparative Example 1. The bimetallic MOR molecular sieves prepared in Examples 1 to 3 have excellent selective adsorption and screening effects on trace Ne in Ne and N2 and Ne and He mixed gases.

[0090] 3. IAST selectivity theoretical calculation:

[0091] Based on the single component adsorption isotherms of the prepared products A1 and B1 of Example 1 and Comparative Example 1 obtained in the above gas adsorption performance test at 77K Figure 2 and Figure 5 The dual-site Langmuir-Freundlich (DSLF) adsorption model was used to Figure 2 and Figure 5 The single component isotherm adsorption line in is fitted, and then the selectivity of the two-component mixed gas is calculated according to the ideal adsorption solution theory (IAST), and the ideal adsorption solution theory (IAST) selectivity result diagram of the binary mixed gas of equal volume (50 / 50, V / V) of Ne and N2 and equal volume (50 / 50, V / V) of Ne and He of the products prepared in Example 1 and Comparative Example 1 is obtained, as shown in FIG. Figure 6 and Figure 7 shown.

[0092] Figure 6 The ideal adsorption solution theory (IAST) selectivity result diagram of the MOR molecular sieve prepared in Example 1 and Comparative Example 1 for Ne / N2 (50 / 50, V / V) binary gas mixture is shown in FIG. Figure 6In the conditions of 77 K and 1 bar, for an equal volume binary mixture of neon and nitrogen, the IAST selectivity of the MOR molecular sieve prepared in Example 1 is 93, and the IAST selectivity of the MOR molecular sieve prepared in Comparative Example 1 is 45;

[0093] Figure 7 The ideal adsorption solution theory (IAST) selectivity result diagram of the MOR molecular sieves prepared in Example 1 and Comparative Example 1 for Ne / He (50 / 50, V / V) binary gas mixture is shown in FIG. Figure 7 In the conditions of 77 K and 1 bar, for an equal volume binary mixture of neon and helium, the IAST selectivity of the MOR molecular sieve prepared in Example 1 is 889, and the IAST selectivity of the MOR molecular sieve prepared in Comparative Example 1 is 417;

[0094] In summary, at 77 K and 1 bar, the IAST selectivity of Ne / N2 and Ne / He in Example 1 is significantly higher than that of Ne / N2 and Ne / He in Comparative Example 1. The above results show that the bimetallic MOR molecular sieve prepared in Example 1 of the invention can efficiently adsorb and remove trace amounts of Ne in N2 and He, and has good selective adsorption performance for Ne.

[0095] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for preparing a bimetallic MOR molecular sieve, characterized in that: The following steps are involved: S1, mixing sodium hydroxide, sodium aluminate and deionized water, and stirring at room temperature for 0.5-3 hours at a speed of 150-400 r / min to obtain a first mixed solution; S2, slowly adding the silicon source dropwise to the first mixed solution, stirring at a speed of 150-400 r / min for 2-6 hours to obtain a second mixed solution; S3, adding the organic metal calcium compound and the organic metal titanium compound to the second mixed solution, stirring at a speed of 150-400 r / min for 10-15 hours to obtain a third mixed solution; in the third mixed solution, the molar ratio of the silicon source, sodium hydroxide, sodium aluminate, deionized water, the organic metal calcium compound and the organic metal titanium compound is 1:0.35:0.1:18:(0.0005-0.005):(0.0001-0.001); Wherein, the organic metal calcium compound is one or more of calcium 2-ketoglutarate, calcium citrate and calcium hexafluoroacetylacetonate; the organic metal titanium compound is one or more of titanium isopropionate, titanium acetylacetonate oxide and titanium tert-butoxide; S4, transferring the third mixed solution to a reactor, and obtaining a bimetallic MOR molecular sieve finished product through hydrothermal crystallization, washing, drying and calcination; wherein the hydrothermal crystallization conditions are: temperature of 170-180° C., and time of 48-90 hours; The bimetallic MOR molecular sieve is used as an adsorbent to selectively separate Ne in a mixed gas, wherein the mixed gas is at least one of N2 and He, and the bimetallic MOR molecular sieve is a porous adsorbent.

2. The method for preparing the bimetallic MOR molecular sieve according to claim 1, characterized in that: In the step S1, stirring is performed at room temperature at a rotation speed of 200-350 r / min for 1 hour.

3. The method for preparing the bimetallic MOR molecular sieve according to claim 1, characterized in that: The silicon source is one or more combinations of silica sol or ethyl orthosilicate.

4. The method for preparing the bimetallic MOR molecular sieve according to claim 1, characterized in that: In the step S2, stirring is performed at a rotation speed of 200-350 r / min for 4 hours.

5. The method for preparing the bimetallic MOR molecular sieve according to claim 1, characterized in that: In the step S3, stirring is performed at a rotation speed of 200-350 r / min for 12 hours.

6. The method for preparing the bimetallic MOR molecular sieve according to claim 1, characterized in that: The organic metal calcium compound is calcium 2-ketoglutarate, and the organic metal titanium compound is titanium isopropionate.

7. The method for preparing the bimetallic MOR molecular sieve according to claim 1, characterized in that: In S4, the washing refers to washing the product with deionized water until it is neutral, and the drying refers to drying at 100-120° C. for 8-12 hours; the calcination conditions are: calcination at 450-550° C. for 4-6 hours, with a heating rate of 6° C. / min.

8. A bimetallic MOR molecular sieve, characterized in that: It is prepared using the preparation method described in any one of claims 1 to 7.

9. The use of the bimetallic MOR molecular sieve as claimed in claim 8 as an adsorbent for selectively separating Ne from a mixed gas, characterized in that: The mixed gas is at least one of N2 and He.

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