Preparation method and application of X-type oxygen production molecular sieve

Abstract

The application discloses a preparation method and application of X-type oxygen production molecular sieve and belongs to the technical field of oxygen production molecular sieve.The present application uses metakaolin, alumina and silicon dioxide as raw materials, adds a template agent mixed by tetrabutylammonium hydroxide and modified graphene into a sodium hydroxide solution, crystallizes to obtain X-type molecular sieve, and then obtains X-type oxygen production molecular sieve through lithium chloride and calcium chloride.The template agent can induce the growth of the molecular sieve in a two-dimensional direction, shortens the gas diffusion path, the phosphoryl of didecylphenyl phosphite improves the thermal stability of the graphene oxide, and the modified graphene improves the pressure strength of the molecular sieve in the molecular sieve;the modified molecular sieve through lithium chloride and calcium chloride improves the nitrogen-oxygen separation coefficient;and the X-type oxygen production molecular sieve prepared by the present application has excellent nitrogen-oxygen separation performance and mechanical strength.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of oxygen production molecular sieve, and particularly relates to a preparation method and application of X-type oxygen production molecular sieve. BACKGROUND

[0002] Molecular sieve is a kind of mineral or synthetic material with special crystal structure and chemical properties, which is mainly composed of silicate, wherein silicon-oxygen tetrahedron and aluminum-oxygen hexahedron are connected with each other by sharing oxygen atoms, the X-type molecular sieve belongs to the cubic system, the internal framework structure of the X-type zeolite is usually negatively charged and has larger pore volume and micropore diameter, which is beneficial to be applied in ion exchanger and adsorbent, etc. LiLSX oxygen production molecular sieve is currently recognized as the best performance of pressure swing adsorption (PSA) separation air oxygen molecular sieve material. In recent years, the PSA oxygen production technology has developed rapidly, and the cost of PSA oxygen production has been greatly reduced, and at present, it has become the mainstream technology for small and medium scale oxygen production.

[0003] The Chinese invention patent with publication number CN116474718B discloses a hydrophobic lithium type oxygen production molecular sieve adsorbent and its preparation method and application, the preparation method of the hydrophobic lithium type oxygen production molecular sieve adsorbent is as follows: (1) mixing molecular sieve raw powder with binder and additive; placing in a rolling ball forming device to control balling, and screening small ball agglomerates; (2) drying, drying and calcining to obtain sodium sieve small ball adsorbent; (3) preparing wet material, inputting soluble lithium salt solution for exchange; washing the lithium exchanged material with LiOH solution to obtain washed material; (4) passing organic silane-toluene solution for surface modification to obtain surface modified adsorbent; after unloading, drying to obtain lithium adsorbent small balls; (5) negative pressure programmed temperature dehydration activation, and then isolating water vapor to cool down, and the product is obtained. The molecular sieve adsorbent of the present application can be applied to the air separation process, high-purity oxygen can be obtained, and has high stability and high separation performance. However, the prior art has the technical problem that the morphology of the X-type molecular sieve is not reasonably modified to improve the nitrogen-oxygen separation performance of the X-type oxygen production molecular sieve. SUMMARY

[0004] The purpose of the present application is to provide a preparation method and application of X-type oxygen production molecular sieve, which solves the technical problem in the prior art that the morphology of the X-type molecular sieve is not reasonably modified to improve the nitrogen-oxygen separation performance of the X-type oxygen production molecular sieve.

[0005] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0006] A preparation method of X-type oxygen production molecular sieve, comprising the following steps:

[0007] S1, pretreatment: washing kaolin, and calcining at 550-600 DEG C for 5-6h to obtain metakaolin;

[0008] S2, preparing X-type molecular sieve: according to mass fraction, 10-15 parts of metakaolin, 0.5-3 parts of alumina and 1-3 parts of water glass are mixed into a mixture, 10-15 parts of the mixture is added into 100-150 parts of 100-120 g / L sodium hydroxide solution, 3-4 parts of template agent is added, stirring at room temperature, aging and crystallization, after the reaction is completed, cooling to room temperature, filtering, washing and drying, calcining at 500-600℃ for 4-6h to prepare X-type molecular sieve;

[0009] S3, modification of X-type molecular sieve: according to mass fraction, lithium chloride and calcium chloride are added into deionized water to prepare lithium chloride and calcium chloride solutions with a concentration of 85-125 g / L, the pH is adjusted to 8.5-9 with lithium hydroxide solution, and then 10-20 parts of X-type molecular sieve is sequentially added into 200-300 parts of lithium chloride and calcium chloride solution for temperature modification, the solid is centrifuged and dried at 80-100℃ to prepare X-type oxygen production molecular sieve.

[0010] As preferred, the chemical composition and ratio of metakaolin in S1 are shown in Table 1:

[0011] Table 1 Chemical composition and ratio of metakaolin

[0012]

[0013] As preferred, the silicon-aluminum molar ratio of the mixture in S2 is 0.8-1.2.

[0014] As preferred, the template agent in S2 is prepared by mixing tetrabutylammonium hydroxide and modified graphene at a mass ratio of 1:1, and the specific operation after adding the template agent is stirring at 500-700 rpm for 10-12h at room temperature, aging at 50-60℃ for 4-6h, and then crystallizing at 80-90℃ for 24-32h.

[0015] As preferred, the specific operation of temperature modification in S3 is modifying at 40-50℃ for 4-6h.

[0016] As preferred, the preparation method of the modified graphene comprises the following steps:

[0017] S11, the waste graphite electrode is heat treated in an argon atmosphere, washed with deionized water to remove impurities, and ground to prepare pretreated graphite;

[0018] S12, by mass parts, 1~2 parts of pretreated graphite and 1~2 parts of sodium nitrate are added into 20~30 parts of 98wt% concentrated sulfuric acid, the system temperature is maintained at 20~25℃, stirring for 2~3h, 2~3 parts of potassium permanganate and 40~50 parts of deionized water are added, the temperature is raised for reaction, 100~150 parts of deionized water and 10~20 parts of 30wt% hydrogen peroxide are added, the system is cooled and filtered to collect the solid, which is washed with deionized water and dried to obtain graphene oxide;

[0019] S13, by mass parts, 2~5 parts of didecyl phenyl phosphite are added into 100~150 parts of dichloromethane, 10~12 parts of sodium hydroxide is dissolved in 100~200 parts of deionized water, and then added dropwise into the system under stirring, stirring for 1~2h, 1~2 parts of graphene oxide is dispersed uniformly in 1000~1500 parts of deionized water to obtain a graphene oxide solution, which is then added into the system, the temperature is raised for reaction, and filtration is performed to obtain modified graphene.

[0020] As preferred, the specific operation of the heat treatment in S11 is to heat to 800~900℃ for 2~3h.

[0021] As preferred, the specific operation of the temperature rising reaction in S12 is to heat to 95~100℃ for 0.5~1h.

[0022] As preferred, the specific operation of the temperature rising reaction in S13 is to heat to 30~40℃ for 20~24h.

[0023] An application of X-type oxygen production molecular sieve for preparing oxygen production adsorbent, the preparation method comprising the following steps:

[0024] S21, according to mass parts, 10~20 parts of kaolin is added into 50~60 parts of deionized water, 1~2 parts of sodium pyrophosphate dispersant is added, stirring and ultrasonic treatment, standing, taking the supernatant through a 300~350 mesh sieve, drying and grinding to obtain pretreated kaolin;

[0025] S22, by mass parts, 10~20 parts of pretreated kaolin is added into 20~30 parts of 10wt% polyaluminum ferric silicate solution for reaction for 5~6h, after filtration and drying, 40~50 parts of 1~2wt% chitosan solution is added, and the mixture is reacted at 50~60℃ for 3~4h, after filtration and drying, modified kaolin is obtained;

[0026] S23, according to mass parts, 10~20 parts of modified kaolin and 30~50 parts of X-type oxygen production molecular sieve are mixed, water kneading, pressing into shape by a press, drying and calcining to obtain oxygen production adsorbent.

[0027] Preferably, the stirring ultrasonic treatment in S21 is performed at a speed of 1000-2000 rpm for 0.5-1 h and at a power of 300-500 W for 0.5-1 h.

[0028] Preferably, the drying and calcination in S23 is performed at a temperature of 80-90 DEG C for 1-2 h, and at a temperature of 450-550 DEG C for 1-2 h.

[0029] In summary, the present application has the following advantages:

[0030] The present application uses metakaolin and alumina as raw materials, adds a template agent of mixed tetrabutylammonium hydroxide and modified graphene into a sodium hydroxide solution, crystallizes to obtain a two-dimensional X-type molecular sieve, and modifies the X-type molecular sieve by lithium chloride and calcium chloride to obtain an X-type oxygen production molecular sieve.

[0031] The X-type molecular sieve of the present application uses metakaolin and alumina as raw materials, thereby reducing the cost of raw materials.

[0032] The present invention uses waste graphite electrodes as raw materials, oxidizes graphene oxide, and then modifies it with didecylphenyl phosphite to obtain modified graphene, which has a spatial barrier effect between layers and inhibits the stacking of graphene layers. Using waste graphite electrodes as raw materials reduces production costs. The waste graphite electrodes have a layered microporous structure, which is easier to peel off under the action of potassium permanganate, and the microporous structure increases the active sites of the graphene oxide. The didecylphenyl phosphite modification increases the active sites on the surface of the graphene oxide, the phosphoryl group of the didecylphenyl phosphite improves the thermal stability of the graphene oxide, the steric hindrance effect of the long-chain alkyl group improves the dispersibility of the graphene in the molecular sieve, and helps the X-type molecular sieve grow in a two-dimensional direction. The modified graphene is doped in the X-type oxygen-producing molecular sieve to improve the mechanical strength of the molecular sieve.

[0033] The present invention modifies kaolin by using polyaluminium ferric silicate and chitosan. The polyaluminium ferric silicate can form an electrostatic interaction network with the X-type oxygen-generating molecular sieve to enhance the binding force. The iron and aluminium active sites of the polyaluminium ferric silicate can synergistically remove trace sulfur gas impurities in the gas. The flexible long chain of chitosan can better combine the kaolin and the original powder of the X-type oxygen-generating molecular sieve. After calcination, the porosity is increased, which is beneficial to gas diffusivity. The modified kaolin avoids the pulverization problem of the X-type oxygen-generating molecular sieve during the high-pressure adsorption-desorption process. The oxygen-generating adsorbent prepared by using the modified kaolin as a binder to bond the X-type oxygen-generating molecular sieve has excellent oxygen-generating and pulverization-resistant properties. DETAILED DESCRIPTION

[0034] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0035] Example 1: A method for preparing an X-type oxygen-producing molecular sieve according to this embodiment comprises the following steps:

[0036] S1. Pretreatment: Wash the kaolin and calcine it at 550°C for 6 hours to obtain metakaolin;

[0037] S2. Preparation of X-type molecular sieve: 2 g of tetrabutylammonium hydroxide and 2 g of modified graphene were mixed to prepare a template, 10 g of metakaolin, 0.7 g of aluminum oxide and 2 g of water glass were prepared into a mixture, 10 g of the mixture was added to 100 g of 100 g / L sodium hydroxide solution, 4 g of the template was added, and the mixture was stirred at a speed of 500 rpm at room temperature for 12 h, heated to 60 ° C and aged for 4 h, and then heated to 80 ° C for crystallization reaction for 24 h. After the reaction, it was cooled to room temperature, filtered, washed and dried, and calcined at 500 ° C for 4 h to obtain X-type molecular sieve;

[0038] S3, X-type molecular sieve modification: 50g of lithium chloride and 50g of calcium chloride were added to 500mL of deionized water to prepare a 100g / L lithium chloride and 100g / L calcium chloride solution, the pH was adjusted to 8.5 with lithium hydroxide solution, 10g of X-type molecular sieve was added to 200g of lithium chloride solution, heated to 40℃ for 4h, and then 200g of calcium chloride solution was added, heated to 40℃ for 4h, centrifugal separation of solids, dried at 100℃ to prepare X-type oxygen production molecular sieve.

[0039] The preparation method of the modified graphene of the embodiment comprises the following steps:

[0040] S11, the waste graphite electrode was heated to 800℃ in an argon atmosphere for 2h, washed with deionized water to remove impurities, and ground to prepare pretreated graphite;

[0041] S12, 1g of pretreated graphite and 1.2g of sodium nitrate were added to 25g of 98wt% concentrated sulfuric acid, the system temperature was maintained at 25℃, stirred for 2h, 2g of potassium permanganate and 40g of deionized water were added, heated to 98℃ for 0.5h, 100g of deionized water and 10g of 30wt% hydrogen peroxide were added, the system was cooled and the solid was collected by filtration, washed with deionized water and dried to prepare graphene oxide;

[0042] S13, 3g of didecylphenyl phosphite was added to 100g of dichloromethane, 10g of sodium hydroxide was dissolved in 100g of deionized water, and then added to the system under stirring, 1g of graphene oxide was added to 1000g of deionized water to disperse uniformly to prepare a graphene oxide solution, and then added to the system, heated to 40℃ for 24h, and filtered to obtain modified graphene.

[0043] The application of the X-type oxygen production molecular sieve of the embodiment is used to prepare an oxygen production adsorbent, and the preparation method comprises the following steps:

[0044] S21, 10g of kaolin was added to 50g of deionized water, 1g of sodium pyrophosphate dispersant was added, stirred at 1000rpm for 0.5h, ultrasonicated at 500W for 0.5h, and then the supernatant was collected and sieved through a 300 mesh sieve, dried and ground to prepare pretreated kaolin;

[0045] S22, 10g of pretreated kaolin was added to 20g of 10wt% polyaluminum ferric silicate solution and reacted for 6h, then filtered and dried, and then added to 40g of 1wt% chitosan solution and reacted at 50℃ for 4h, then filtered and dried to obtain modified kaolin;

[0046] S23. Mix 10 g of modified kaolin and 30 g of X-type oxygen-generating molecular sieve, add water and knead, press into shape using a plodder, heat to 90° C. and dry for 2 h, and calcine at 500° C. for 2 h to obtain an oxygen-generating adsorbent.

[0047] Example 2: A method for preparing an X-type oxygen-producing molecular sieve according to this embodiment comprises the following steps:

[0048] S1. Pretreatment: Wash the kaolin and calcine it at 600°C for 5h to obtain metakaolin;

[0049] S2. Preparation of X-type molecular sieve: 1.5 g of tetrabutylammonium hydroxide and 1.5 g of modified graphene were mixed to prepare a template, 10 g of metakaolin, 1.8 g of aluminum oxide and 2.5 g of water glass were prepared into a mixture, 14 g of the mixture was added to 150 g of 120 g / L sodium hydroxide solution, 3 g of the template was added, and the mixture was stirred at a speed of 600 rpm at room temperature for 10 h, heated to 60 ° C and aged for 6 h, and then heated to 85 ° C for crystallization reaction for 28 h. After the reaction, it was cooled to room temperature, filtered, washed and dried, and calcined at 550 ° C for 4 h to obtain X-type molecular sieve;

[0050] S3. Modification of X-type molecular sieve: 60 g of lithium chloride and 60 g of calcium chloride were respectively added to 500 mL of deionized water to prepare lithium chloride and 120 g / L calcium chloride solutions, and the pH was adjusted to 9 with lithium hydroxide solution. Then, 15 g of two-dimensional X-type molecular sieve was added to 250 g of lithium chloride solution, and the temperature was raised to 50°C for modification for 4 hours. Finally, it was added to 250 g of calcium chloride solution, and the temperature was raised to 50°C for modification for 4 hours. The solid was separated by centrifugation and dried at 80°C to obtain X-type oxygen-generating molecular sieve.

[0051] The application of an X-type oxygen-generating molecular sieve in this embodiment is used to prepare an oxygen-generating adsorbent. The preparation method includes the following steps:

[0052] S21, adding 20 g of kaolin to 60 g of deionized water, adding 1.5 g of sodium pyrophosphate dispersant, stirring at a speed of 1500 rpm for 1 hour, ultrasonicating at a power of 300 W for 0.5 hour, letting it stand, taking the supernatant and passing it through a 350 mesh sieve, drying and grinding to obtain pretreated kaolin;

[0053] S22, adding 20g of pretreated kaolin to 30g of 10wt% polysilicate aluminum ferric solution and reacting for 6h, filtering and drying, then adding 50g of 2wt% chitosan solution, reacting at 50°C for 3h, filtering and drying to obtain modified kaolin;

[0054] S23. Mix 20 g of modified kaolin and 30 g of X-type oxygen-generating molecular sieve, add water and knead, press into shape using a plodder, heat to 80° C. and dry for 1 h, and calcine at 450° C. for 2 h to obtain an oxygen-generating adsorbent.

[0055] The preparation method of the modified graphene in this embodiment is the same as that in Example 1.

[0056] Example 3: A method for preparing an X-type oxygen-producing molecular sieve according to this embodiment comprises the following steps:

[0057] S1. Pretreatment: Wash the kaolin and calcine it at 550°C for 6 hours to obtain metakaolin;

[0058] S2. Preparation of X-type molecular sieve: 2 g of tetrabutylammonium hydroxide and 2 g of modified graphene were mixed to prepare a template, 15 g of metakaolin, 0.6 g of aluminum oxide and 1 g of water glass were prepared into a mixture, 15 g of the mixture was added to 100 g of 110 g / L sodium hydroxide solution, 4 g of the template was added, and the mixture was stirred at a speed of 700 rpm at room temperature for 10 h, heated to 50 ° C and aged for 6 h, and then heated to 80 ° C for crystallization reaction for 30 h. After the reaction was completed, it was cooled to room temperature, filtered, washed and dried, and calcined at 500 ° C for 5 h to obtain X-type molecular sieve;

[0059] S3. Modification of X-type molecular sieve: 45 g of lithium chloride and 45 g of calcium chloride were respectively added to 500 mL of deionized water to prepare lithium chloride and 90 g / L calcium chloride solutions, and the pH was adjusted to 8.5 with lithium hydroxide solution. Then, 15 g of two-dimensional X-type molecular sieve was added to 300 g of lithium chloride solution, and the temperature was raised to 40°C for modification for 4 hours. Finally, it was added to 300 g of calcium chloride solution, and the temperature was raised to 40°C for modification for 4 hours. The solid was separated by centrifugation and dried at 90°C to obtain X-type oxygen-producing molecular sieve.

[0060] The application of an X-type oxygen-generating molecular sieve in this embodiment is used to prepare an oxygen-generating adsorbent. The preparation method includes the following steps:

[0061] S21, adding 15 g of kaolin to 50 g of deionized water, adding 1 g of sodium pyrophosphate dispersant, stirring at a speed of 1200 rpm for 1 h, ultrasonicating at a power of 500 W for 1 h, letting it stand, taking the supernatant and passing it through a 300 mesh sieve, drying and grinding to obtain pretreated kaolin;

[0062] S22, adding 15g of pretreated kaolin to 20g of 10wt% polysilicate aluminum ferric solution and reacting for 5h, filtering and drying, then adding 50g of 2wt% chitosan solution, reacting at 60°C for 3h, filtering and drying to obtain modified kaolin;

[0063] S23. Mix 10 g of modified kaolin and 50 g of X-type oxygen-generating molecular sieve, add water and knead, press into shape using a plodder, heat to 90° C. and dry for 2 h, and calcine at 550° C. for 1 h to obtain an oxygen-generating adsorbent.

[0064] The preparation method of the modified graphene in this embodiment is the same as that in Example 1.

[0065] Example 4: A method for preparing an X-type oxygen-producing molecular sieve according to this embodiment comprises the following steps:

[0066] S1. Pretreatment: Wash the kaolin and calcine it at 600°C for 6 hours to obtain metakaolin;

[0067] S2. Preparation of X-type molecular sieve: 1.5 g of tetrabutylammonium hydroxide and 1.5 g of modified graphene were mixed to prepare a template, 10 g of metakaolin, 1.1 g of aluminum oxide and 1 g of water glass were prepared into a mixture, 10 g of the mixture was added to 100 g of 120 g / L sodium hydroxide solution, 3 g of the template was added, and the mixture was stirred at a speed of 500 rpm at room temperature for 10 h, heated to 60 ° C and aged for 4 h, and then heated to 80 ° C for crystallization reaction for 32 h. After the reaction, it was cooled to room temperature, filtered, washed and dried, and calcined at 550 ° C for 4 h to obtain X-type molecular sieve;

[0068] S3. Modification of X-type molecular sieve: 55 g of lithium chloride and 55 g of calcium chloride were respectively added to 500 mL of deionized water to prepare lithium chloride and 110 g / L calcium chloride solutions, and the pH was adjusted to 9 with lithium hydroxide solution. Then, 20 g of X-type molecular sieve was added to 200 g of lithium chloride solution, and the temperature was raised to 50°C for modification for 6 h. Finally, it was added to 200 g of calcium chloride solution, and the temperature was raised to 50°C for modification for 6 h. The solid was separated by centrifugation and dried at 100°C to obtain X-type oxygen-generating molecular sieve.

[0069] The application of an X-type oxygen-generating molecular sieve in this embodiment is used to prepare an oxygen-generating adsorbent. The preparation method includes the following steps:

[0070] S21, adding 20g of kaolin to 60g of deionized water, adding 1g of sodium pyrophosphate dispersant, stirring at a speed of 2000rpm for 0.5h, ultrasonicating at a power of 300W for 0.5h, letting it stand, taking the supernatant and passing it through a 350-mesh sieve, drying and grinding to obtain pretreated kaolin;

[0071] S22, adding 20g of pretreated kaolin to 30g of 10wt% polysilicate aluminum ferric solution and reacting for 5h, filtering and drying, then adding 40g of 1wt% chitosan solution, reacting at 50°C for 3h, filtering and drying to obtain modified kaolin;

[0072] S23. Mix 20 g of modified kaolin and 50 g of X-type oxygen-generating molecular sieve, add water and knead, press into shape using a plodder, heat to 80° C. and dry for 2 h, and calcine at 450° C. for 1 h to obtain an oxygen-generating adsorbent.

[0073] The difference between the modified graphene of this embodiment and that of Example 1 is that the masses of graphene oxide and didecylphenyl phosphite in S13 are replaced by 2 g of graphene oxide and 5 g of didecylphenyl phosphite.

[0074] Comparative Example 1: The difference between this comparative example and Example 1 is that no modified graphene is added during the preparation of the X-type oxygen-producing molecular sieve.

[0075] Comparative Example 2: The difference between this comparative example and Example 1 is that no template is added during the preparation of the X-type oxygen-generating molecular sieve.

[0076] Comparative Example 3: This comparative example differs from Example 1 in that the modified kaolin is replaced by bentonite.

[0077] Comparative Example 4: This comparative example differs from Example 1 in that the X-type oxygen-making molecular sieve raw material is replaced with 15 g of metakaolin and 1.5 g of silicon dioxide so that the silicon-aluminum molar ratio is greater than 1.3.

[0078] Performance Testing

[0079] Activation pretreatment: The X-type oxygen-generating molecular sieve and oxygen-generating adsorbent prepared in each embodiment and comparative example were placed in a vacuum oven, heated to 400° C. under vacuum conditions and activated for 2 h.

[0080] The activated X-type oxygen-generating molecular sieves and oxygen-generating adsorbents prepared in accordance with the Examples and Comparative Examples of GB / T 35109-2017 "Static Determination of Nitrogen and Oxygen Separation by Molecular Sieve" were tested for nitrogen and oxygen separation coefficients and static saturated nitrogen adsorption capacity at 298K and 0.1MPa. The saturated oxygen-generating adsorbents were vacuum-treated at 400°C for 3 h, and the treated molecular sieves were then subjected to a gas adsorption performance test. The nitrogen and oxygen separation coefficients and static saturated nitrogen adsorption capacity after regeneration were measured.

[0081] The test results are shown in Table 2:

[0082] Table 2 Gas adsorption performance test results

[0083]

[0084] The crushing rates of the X-type oxygen-generating molecular sieves prepared in each example and comparative example were measured at 150N and 250N according to HG / T 2783-2020 "Test Method for Crush Resistance of Molecular Sieve". The test results are shown in Table 3:

[0085] Table 3 Breakage rate test results

[0086]

[0087] From the data in the table above, it can be seen that the nitrogen-oxygen separation coefficient of the X-type oxygen-generating molecular sieves prepared in Examples 1 to 4 is between 5.59 and 5.76 at 298K and 0.1MPa, and the static saturated adsorption capacity of nitrogen is between 20.56 and 21.67 cm 3 / g, the template agent was not added during the preparation of the X-type oxygen-generating molecular sieve of Comparative Example 2, resulting in the nitrogen-oxygen separation coefficient of the prepared X-type oxygen-generating molecular sieve being 5.05, and the static saturated adsorption capacity of nitrogen being 17.65 cm 3 / g, which is much smaller than the data in the examples, indicating that the X-type oxygen-generating molecular sieve prepared by the present invention has excellent nitrogen-oxygen separation performance and nitrogen adsorption capacity; the nitrogen-oxygen separation coefficients of the oxygen-generating adsorbents prepared in Examples 1 to 4 are between 5.22 and 5.67, and the static saturated adsorption capacity of nitrogen is 19.23 to 21.28 cm 3 / g, the nitrogen-oxygen separation coefficient after regeneration is between 5.12 and 5.58, and the static saturated adsorption capacity of nitrogen is 18.82 to 20.73 cm 3 / g, indicating that the X-type oxygen-producing molecular sieve prepared by the present invention can maintain stable nitrogen and oxygen separation performance when used in the preparation of oxygen-producing adsorbents, and has excellent regeneration adsorption performance; the X-type oxygen-producing molecular sieves prepared in Examples 1 to 4 have a crushing rate of 2.08% to 2.36% under 150N, and a crushing rate of 3.24% to 3.61% under 250N, indicating that the X-type oxygen-producing molecular sieve prepared by the present invention has excellent mechanical strength.

[0088] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with this technical field, within the technical scope disclosed by the present invention, can make equivalent replacements or changes based on the technical solutions and inventive concepts of the present invention, which should be covered by the scope of protection of the present invention.

[0089] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to specific embodiments. Obviously, many modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for preparing an X-type oxygen-producing molecular sieve, characterized in that: The steps include: S1. Pretreatment: Wash the kaolin and calcine it at 550-600℃ for 5-6h to obtain metakaolin; S2. Preparation of type X molecular sieve: by weight, 10-15 parts of metakaolin, 0.5-3 parts of alumina and 1-3 parts of water glass are mixed, 10-15 parts of the mixture are added to 100-150 parts of 100-120 g / L sodium hydroxide solution, 3-4 parts of a template are added, the mixture is stirred at room temperature, aged and crystallized, and after the reaction is completed, it is cooled to room temperature, filtered, washed and dried, and calcined at 500-600 ° C for 4-6 hours to obtain type X molecular sieve; S3. Modification of X-type molecular sieve: lithium chloride and calcium chloride were added to deionized water in parts by mass to prepare lithium chloride and calcium chloride solutions with a concentration of 85-125 g / L, and the pH was adjusted to 8.5-9 with lithium hydroxide solution. Then, 10-20 parts of X-type molecular sieve were added to 200-300 parts of lithium chloride and calcium chloride solutions in sequence and the temperature was increased for modification. The solid was separated by centrifugation and dried at 80-100°C to obtain X-type oxygen-generating molecular sieve; The silicon-aluminum molar ratio of the mixture in S2 is 0.8-1.2, and the template is prepared by mixing tetrabutylammonium hydroxide and modified graphene in a mass ratio of 1:

1. The specific operation after adding the template is to stir at a speed of 500-700 rpm at room temperature for 10-12 hours, heat to 50-60°C for aging for 4-6 hours, and then heat to 80-90°C for crystallization reaction for 24-32 hours; The preparation method of the modified graphene comprises the following steps: S11, placing the discarded graphite electrode in an argon atmosphere for heat treatment, washing with deionized water to remove impurities, and grinding to obtain pretreated graphite; S12. Add 1 to 2 parts of pretreated graphite and 1 to 2 parts of sodium nitrate to 20 to 30 parts of 98 wt % concentrated sulfuric acid, maintain the system temperature at 20 to 25 ° C, stir for 2 to 3 hours, add 2 to 3 parts of potassium permanganate and 40 to 50 parts of deionized water, raise the temperature to react, add 100 to 150 parts of deionized water and 10 to 20 parts of 30 wt % hydrogen peroxide, cool the system, filter and collect the solid, wash with deionized water, and dry to obtain graphene oxide; S13. Add 2-5 parts of didecylphenyl phosphite to 100-150 parts of dichloromethane by mass, dissolve 10-12 parts of sodium hydroxide in 100-200 parts of deionized water, and then add the mixture dropwise to the system under stirring. Stir for 1-2 hours, add 1-2 parts of graphene oxide to 1000-1500 parts of deionized water, disperse the mixture evenly to obtain a graphene oxide solution, and then add the mixture to the system. Heat the reaction, filter, and obtain modified graphene.

2. The method for preparing an X-type oxygen-producing molecular sieve according to claim 1, characterized in that: The specific operation of the temperature-raising modification in S3 is to raise the temperature to 40-50° C. and perform modification for 4-6 hours.

3. The method for preparing an X-type oxygen-producing molecular sieve according to claim 1, characterized in that: The specific operation of the heat treatment in S11 is to heat the mixture to 800-900°C for 2-3 hours; the specific operation of the temperature reaction in S12 is to heat the mixture to 95-100°C for 0.5-1 hour; and the specific operation of the temperature reaction in S13 is to heat the mixture to 30-40°C for 20-24 hours.

4. Application of an X-type oxygen-producing molecular sieve prepared by the method according to any one of claims 1 to 3, characterized in that: For preparing an oxygen-generating adsorbent, the preparation method comprises the following steps: S21. Add 10-20 parts of kaolin to 50-60 parts of deionized water, add 1-2 parts of sodium pyrophosphate dispersant, stir and ultrasonicate, let stand, take the supernatant and pass it through a 300-350 mesh sieve, dry and grind to obtain pretreated kaolin; S22, adding 10-20 parts by mass of pretreated kaolin to 20-30 parts of 10 wt% polysilicate aluminum ferric solution, reacting for 5-6 hours, filtering and drying, then adding 40-50 parts of 1-2 wt% chitosan solution, reacting at 50-60° C. for 3-4 hours, filtering and drying to obtain modified kaolin; S23. Mix 10-20 parts of modified kaolin and 30-50 parts of X-type oxygen-generating molecular sieve according to parts by mass, add water and knead, press into shape with a plodder, and dry and roast to obtain an oxygen-generating adsorbent.

5. The use of an X-type oxygen-producing molecular sieve according to claim 4, characterized in that: The specific operation of the stirring and ultrasonic treatment in S21 is stirring at a speed of 1000-2000 rpm for 0.5-1 hour and ultrasonicating at a power of 300-500 W for 0.5-1 hour; the specific operation of the drying and roasting in S23 is heating to 80-90°C for drying for 1-2 hours and roasting at 450-550°C for 1-2 hours.

Images