CN112875720B - Method for preparing aluminum pair-enriched SSZ-13 molecular sieve and application thereof - Google Patents
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Abstract
The invention discloses a method for preparing an aluminum pair-enriched SSZ-13 molecular sieve and application thereof, comprising the following steps: mixing a silicon source, alkali metal hydroxide and water, and activating to obtain an activated mixture; mixing a template agent, a low-silicon molecular sieve, water and seed crystals, adding the activated mixture, and fully and uniformly stirring to obtain initial gel; and transferring the initial gel to a reaction kettle for crystallization, and centrifuging, washing, drying and roasting a product after crystallization to obtain the SSZ-13 molecular sieve. The preparation method provided by the invention has the advantages of simple process and convenient operation, and the prepared SSZ-13 molecular sieve rich in aluminum pairs has high aluminum pair content and high hydrothermal stability of the Cu/SSZ-13 molecular sieve.
Description
Technical Field
The invention belongs to the technical field of molecular sieves, and particularly relates to a method for preparing an aluminum pair-enriched SSZ-13 molecular sieve and application thereof.
Background
The SSZ-13 molecular sieve is a small-pore molecular sieve with Chabazite (CHA) topological structure, the framework structure of the molecular sieve is composed of a hexagonal prism consisting of four-membered rings and six-membered rings, and the space arrangement of the basic units forms a CHA super cage
And an eight-membered ring
A tunnel. The SSZ-13 molecular sieve has great advantages and development potential in the fields of environmental catalysis and gas adsorption separation.
The motor vehicle tail gas contains a large amount of pollutants, which are one of the important reasons for damaging air quality and harming human health, wherein Nitrogen Oxide (NO) x ) The harm of the diesel engine is the largest, and the nitrogen oxide discharged by the diesel engine accounts for more than 60 percent of the total discharge of the diesel engine. With the stricter and stricter emission regulations of automobiles, the nitrogen oxide emission of diesel vehiclesThe discharge and treatment are of great significance. Ammonia selective catalytic reduction technology (NH) 3 -SCR) refers to the selective reduction of nitrogen oxides to nitrogen using ammonia as a reducing agent under oxygen-rich conditions for the purpose of removing nitrogen oxides. The copper-exchanged SSZ-13 molecular sieve shows excellent catalytic performance in selective catalytic reduction reaction, has a wider active temperature window and has NO at 250-450 DEG C x The conversion rate is up to more than 90%. The small pore structure of SSZ-13 can effectively inhibit by-product NO 2 And N 2 O production and increase of N 2 Selectivity; in addition, the removal of skeleton Al in the high-temperature hydrothermal aging process can be inhibited, so that the hydrothermal stability is improved, and the method has a wide application prospect in the field of diesel vehicle tail gas denitration.
The zeolite conversion is a commonly used molecular sieve preparation method, zeolite raw materials are dissolved into nano structural units in an alkaline environment through desilication, and the structural units are selectively reassembled to generate the target molecular sieve under specific structure directing agents and crystallization conditions. High silicon Y is a commonly used feedstock for SSZ-13 preparation by zeolite conversion, but is relatively costly, whereas ordinary Y molecular sieves have a silica to alumina ratio below the synthesis range of SSZ-13. The invention patent application CN111017950A uses the Y-type molecular sieve which is subjected to dealuminization and hydrothermal treatment as a raw material to prepare the SSZ-13 molecular sieve, the method greatly reduces the using amount of organic amine, but the preparation process of the high-silicon Y is complex and has high cost. The invention patent application CN111330635A takes a ZSM-5 molecular sieve as a raw material, and converts the molecular sieve into an SSZ-13 molecular sieve under the action of a template, but the framework structures of the ZSM-5 and the SSZ-13 do not have a common composition building unit, so that the template dosage is large, the product yield is low, and analcite heterogeneous phase is easy to appear. The invention patent application CN111484037A firstly synthesizes a Y molecular sieve with Si/Al of 10-30, and the Y molecular sieve is used as a crystal transformation seed to be mixed with a silicon source, an aluminum source, an alkali liquor and a template agent to prepare the SSZ-13 molecular sieve, wherein the Y molecular sieve is not used as a main raw material, and the addition amount of the Y molecular sieve only accounts for 0.1-10% of the sol.
The SSZ-13 molecular sieve has a skeleton electronegativity and a proton-hydrogen equilibrium skeleton due to the replacement of silicon by aluminumCharge formation of B acid centers, Cu 2+ By substitution of H + Loaded in the channels of the molecular sieve. In the Si-Al molecular sieve, the more distant aluminum forms [ Al-O- (Si-O) n -Al](n.gtoreq.3) structure, is called isolated aluminum, while the closer aluminum is called aluminum pair. The distribution of framework aluminum has important influence on the acidity of the Cu/SSZ-13 molecular sieve and the state of a copper ion active center, thereby influencing the catalytic activity and hydrothermal stability. The copper ion coordinated with the isolated aluminum is positioned in an eight-membered ring, has weak stability, and easily forms a side reaction active center CuO in the hydrothermal aging process x ，CuO x The particles are continuously gathered to destroy the framework structure of the molecular sieve, and the copper ions coordinated with the aluminum pairs are positioned in a double six-membered ring and have stronger stability. Therefore, the preparation of the SSZ-13 molecular sieve rich in aluminum pairs is beneficial to improving the distribution state of copper ion active sites and improving the hydrothermal stability. The invention patent application CN111514929A prepares Cu/SSZ-13 molecular sieve with double aluminum centers by adding a guiding agent solution containing a copper source precursor, a template agent and a seed crystal, but the copper complex is used as the template agent, so that the copper content of the product is too high, and the catalytic activity and the hydrothermal stability of the product are influenced.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provides a method for preparing an SSZ-13 molecular sieve rich in aluminum pairs and application thereof, the preparation method is simple in process and convenient to operate, the prepared SSZ-13 molecular sieve rich in aluminum pairs is high in aluminum pair content, and the Cu/SSZ-13 molecular sieve is high in hydrothermal stability.
The invention provides the following technical scheme:
a process for preparing an aluminum pair enriched SSZ-13 molecular sieve comprising the steps of:
mixing a silicon source, alkali metal hydroxide and water, and activating to obtain an activated mixture;
mixing a template agent, a low-silicon molecular sieve, water and seed crystals, adding the activated mixture, and fully and uniformly stirring to obtain initial gel;
and transferring the initial gel into a reaction kettle for crystallization, and centrifuging, washing, drying and roasting a product after crystallization to obtain the SSZ-13 molecular sieve.
Further, the silicon source is any one of silica sol, white carbon black and sodium silicate; the alkali metal hydroxide is a mixture of LiOH and any one of NaOH, KOH, RbOH and CsOH, wherein the molar content of LiOH is 1-50%.
Further, the silicon source, the alkali metal hydroxide and the water are mixed and then activated for 1-12 hours at the temperature of 90-200 ℃.
Further, OH in the activation mixture - The concentration of (b) is 0.1 to 6mol/L, preferably 1 to 4.5 mol/L.
Further, the template agent is any one of N, N, N-trimethyl-1-adamantyl ammonium hydroxide, N, N, N-trimethyl-1-adamantyl ammonium chloride, N, N, N-trimethyl-1-adamantyl ammonium bromide and N, N, N-trimethyl-1-adamantyl ammonium iodide.
Further, the low-silicon molecular sieve is any one of Na-type A, X, Y molecular sieves or other silicon-aluminum molecular sieves with the framework density smaller than SSZ-13.
Further, the seed crystal is obtained by mechanical crushing, acid corrosion or alkali corrosion of the SSZ-13 molecular sieve; the addition amount of the seed crystal accounts for 0.1-15 wt% of the total mass of the initial gel, and preferably 0.5-10 wt%.
Further, the molar composition of the initial gel is (100-180) SiO 2 ：(1～10)Al 2 O 3 ：(5～15)MOH：(2000～4500)H 2 O: (5-35) SDA, wherein M is alkali metal, and SDA is a template agent.
Further, the crystallization temperature of the initial gel is 100-180 ℃, and the crystallization time is 1-5 days.
Further, the product after crystallization was centrifuged, washed with deionized water until the filtrate had a pH of less than 9, dried in an oven at 100 ℃ for 12 hours, and calcined at 600 ℃ for 5 hours.
The SSZ-13 molecular sieve rich in aluminum pairs prepared by the method is loaded with transition metals and then applied to ammonia selective catalytic reduction reaction to remove nitrogen oxides.
Compared with the prior art, the invention has the beneficial effects that:
(1) the method for preparing the aluminum pair-enriched SSZ-13 molecular sieve provided by the invention takes the cheap low-silicon molecular sieve and the external silicon source as raw materials, overcomes the defect of high cost of the commonly used high-silicon Y raw material, and has the advantages of small using amount of a template agent in a zeolite transformation route, high product yield and short crystallization time;
(2) the method activates the additional silicon source through alkali heat treatment, so that the reaction rate of the additional silicon source is matched with that of the raw material molecular sieve, and the utilization rate of the raw material is improved;
(3) the alkali metal ion has important function in the synthesis of the silicon-aluminum molecular sieve, not only the positive charge of the alkali metal ion is matched with the negative charge quantity of the framework aluminum, but also the positive charge density and the negative charge density are matched, the positive charge density is related to the size of the alkali metal ion, and the framework negative charge density is related to the framework density, the aluminum content and the aluminum distribution + The aluminum distribution of the product is effectively regulated and controlled, the SSZ-13 molecular sieve rich in aluminum pairs is prepared, the content of the aluminum pairs is high, and the hydrothermal stability of the Cu/SSZ-13 molecular sieve is favorably improved;
(4) the method for preparing the SSZ-13 molecular sieve rich in aluminum pairs has simple process and convenient operation.
Drawings
FIG. 1 is an X-ray diffraction pattern of an aluminum pair-enriched SSZ-13 molecular sieve prepared in examples 1, 2 and comparative examples 1, 2;
FIG. 2 is NH of fresh and aged samples of example 1 and comparative example 2 3 -SCR evaluation results graph.
Detailed Description
The invention is further described below with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.
The detection instrument used by the invention comprises: fourier transform infrared analyzer (model MKS MultiGas 6030), X-ray diffractometer (model PANalytical X' Pert Powder), inductively coupled plasma emission spectrometer (model ThermoCAP 7000).
The Cu/SSZ-13 molecular sieves of the following examples were used in ammonia selective catalysisThe specific method of the reduction reaction comprises the following steps: tabletting, crushing and sieving the molecular sieve powder, and collecting particles with the size of 40-60 meshes as a molecular sieve catalyst; the catalyst particles were loaded into a fixed bed reactor and 500ppm NO, 500ppm NH were introduced 3 ，5％O 2 ，8％CO 2 ，3.5％H 2 O，N 2 Equilibrium, volume space velocity 480000h -1 . And (3) carrying out ammonia selective catalytic reduction reaction at 100-600 ℃, and carrying out online detection and quantitative analysis on the product by using a Fourier transform infrared analyzer.
The hydrothermal aging treatment conditions of the Cu/SSZ-13 molecular sieve in the following examples are as follows: heating to 750 deg.C, introducing 10% water vapor, and aging for 24 hr.
Examples the SSZ-13 molecular sieves in the following examples were made by Co 2+ The specific method for measuring the content of the aluminum pair by exchange comprises the following steps: adding the calcined SSZ-13 molecular sieve powder to 0.05mol/L Co (NO) 3 ) 2 The solution was exchanged for 4 hours at room temperature, and 150ml Co (NO) per gram of sample was required 3 ) 2 The solution was repeatedly exchanged three times, and then the sample was centrifuged, washed until the filtrate pH was neutral, and dried in an oven at 100 ℃ for 12 hours, followed by ICP test. The molar amount of Co in the exchanged Co/SSZ-13 is M 1 The molar amount of Al is M 2 Then the content of aluminum pairs is 2 x M 1 /M 2 *100％。
Example 1
Mixing a certain mass of silica sol, LiOH, NaOH and water, and then carrying out activation treatment for 10 hours at 100 ℃, wherein the molar ratio of LiOH to NaOH is 1: 10, OH - The concentration was 4.5 mol/L. Cooling the mixture to room temperature after activation, adding N, N, N-trimethyl-1-adamantyl ammonium hydroxide, NaX molecular sieve, SSZ-13 seed crystal and water, and stirring to obtain initial gel, wherein the molar composition of the initial gel is 180SiO 2 ：10Al 2 O 3 ：12MOH：4500H 2 O: 35SDA, and the addition amount of the seed crystal accounts for 10 wt% of the total mass of the initial gel. The initial gel mixture is stirred evenly and then transferred to a stainless steel reaction kettle for crystallization for 5 days at 100 ℃. After crystallization is finished, the solid crystallization product is centrifugally separated from mother liquor, and is washed by deionized water until the pH value of filtrate is reached<9, drying in an oven at 100 deg.C for 12 hr, and calcining at 600 deg.C for 5 hrObtaining the SSZ-13 molecular sieve. X-ray diffraction showed SSZ-13 molecular sieve (see FIG. 1) with high aluminum content (Table 1) and good NH after copper loading 3 SCR reactivity and hydrothermal stability (see fig. 2).
Example 2
Mixing a certain mass of sodium silicate, LiOH, CsOH and water, and then activating at 90 ℃ for 12 hours, wherein the molar ratio of LiOH to CsOH is 1: 1, OH - The concentration was 6 mol/L. Cooling the mixture to room temperature after activation, adding N, N, N-trimethyl-1-adamantyl ammonium bromide, NaA molecular sieve, SSZ-13 seed crystal and water, and stirring to obtain initial gel, wherein the molar composition of the initial gel is 160SiO 2 ：10Al 2 O 3 ：13MOH：4000H 2 O: 30SDA, the amount of seed added is 15wt% of the total mass of the initial gel. The initial gel mixture is stirred evenly and then transferred to a stainless steel reaction kettle for crystallization for 1 day at 180 ℃. After crystallization is finished, the solid crystallization product is centrifugally separated from mother liquor, and is washed by deionized water until the pH value of filtrate is reached<9, drying and roasting to obtain the SSZ-13 molecular sieve. X-ray diffraction showed SSZ-13 molecular sieve (see FIG. 1) with high aluminum content (Table 1) and good NH after copper loading 3 SCR reactivity and hydrothermal stability (see Table 2).
Example 3
Mixing a certain mass of white carbon black, LiOH, KOH and water, and then activating at 200 ℃ for 1 hour, wherein the molar ratio of LiOH to KOH is 1: 4, OH - The concentration was 0.1 mol/L. Cooling the mixture to room temperature after activation, adding N, N, N-trimethyl-1-adamantane ammonium chloride, NaY molecular sieve, SSZ-13 seed crystal and water, and stirring to obtain initial gel, wherein the molar composition of the initial gel is 100SiO 2 ：4Al 2 O 3 ：10MOH：3300H 2 O: 19SDA, the addition amount of the seed crystal accounts for 0.5 wt% of the total mass of the initial gel. The initial gel mixture was stirred well and transferred to a stainless steel reaction vessel and crystallized at 120 ℃ for 4 days. After crystallization is finished, the solid crystallization product is centrifugally separated from mother liquor, and is washed by deionized water until the pH value of filtrate is reached<And 9, drying and roasting to obtain the SSZ-13 molecular sieve. It contains a high aluminum pair content (Table 1) and has good NH after copper loading 3 -SCR reactionActivity and hydrothermal stability (see table 2).
Example 4
Mixing a certain mass of silica sol, LiOH, RbOH and water, and then carrying out activation treatment for 8 hours at 120 ℃, wherein the molar ratio of LiOH to RbOH is 2: 3, OH - The concentration is 1 mol/L. Cooling the mixture to room temperature after activation, adding N, N, N-trimethyl-1-adamantyl ammonium iodide, NaY molecular sieve, SSZ-13 seed crystal and water, and stirring to obtain initial gel, wherein the molar composition of the initial gel is 120SiO 2 ：5Al 2 O 3 ：8MOH：2500H 2 O: 22SDA, the amount of seed crystal added is 5wt% of the total mass of the initial gel. The initial gel mixture was stirred well and transferred to a stainless steel reaction vessel and crystallized at 150 ℃ for 3 days. After crystallization is finished, the solid crystallization product is centrifugally separated from mother liquor, and is washed by deionized water until the pH value of filtrate is reached<And 9, drying and roasting to obtain the SSZ-13 molecular sieve. It contains high aluminum pair content (Table 1), and has good NH after loading copper 3 SCR reactivity and hydrothermal stability (see Table 2).
Example 5
Mixing a certain mass of silica sol, LiOH, KOH and water, and then carrying out activation treatment at 180 ℃ for 2 hours, wherein the molar ratio of LiOH to KOH is 1: 20, OH - The concentration was 0.5 mol/L. Cooling the mixture to room temperature after activation, adding N, N, N-trimethyl-1-adamantyl ammonium hydroxide, NaX molecular sieve, SSZ-13 seed crystal and water, and stirring to obtain initial gel, wherein the molar composition of the initial gel is 130SiO 2 ：7Al 2 O 3 ：5MOH：2000H 2 O: 8SDA, the addition amount of the seed crystal accounts for 0.1 wt% of the total mass of the initial gel. The initial gel mixture is stirred evenly and then transferred to a stainless steel reaction kettle for crystallization for 2 days at 160 ℃. After crystallization is finished, the solid crystallization product is centrifugally separated from mother liquor, and is washed by deionized water until the pH value of filtrate is reached<9, drying and roasting to obtain the SSZ-13 molecular sieve. It contains high aluminum pair content (Table 1), and has good NH after loading copper 3 SCR reactivity and hydrothermal stability (see table 2).
Example 6
Mixing a certain mass of sodium silicate, LiOH, NaOH and water, and activating at 140 ℃ for 6 hours, wherein LiO isThe molar ratio of H to NaOH is 1: 15, OH - The concentration is 2 mol/L. Cooling the mixture to room temperature after activation, adding N, N, N-trimethyl-1-adamantyl ammonium iodide, NaX molecular sieve, SSZ-13 seed crystal and water, and stirring to obtain initial gel, wherein the molar composition of the initial gel is 170SiO 2 ：5Al 2 O 3 ：9MOH：3000H 2 O: 14SDA, the amount of seed added is 1 wt% of the total mass of the initial gel. The initial gel mixture is stirred evenly and then transferred to a stainless steel reaction kettle for crystallization for 4 days at 140 ℃. After crystallization is finished, the solid crystallization product is centrifugally separated from mother liquor, and is washed by deionized water until the pH value of filtrate<9, drying and roasting to obtain the SSZ-13 molecular sieve. It contains high aluminum pair content (Table 1), and has good NH after loading copper 3 SCR reactivity and hydrothermal stability (see table 2).
Example 7
Mixing a certain mass of white carbon black, LiOH, RbOH and water, and then carrying out activation treatment for 7 hours at 150 ℃, wherein the molar ratio of LiOH to RbOH is 1: 2, OH - The concentration was 3.5 mol/L. Cooling the mixture to room temperature after activation, adding N, N, N-trimethyl-1-adamantyl ammonium bromide, NaA molecular sieve, SSZ-13 seed crystal and water, and stirring to obtain initial gel, wherein the molar composition of the initial gel is 110SiO 2 ：9Al 2 O 3 ：15MOH：2600H 2 O: 32SDA, the amount of seed added is 3 wt% of the total mass of the initial gel. The initial gel mixture was stirred well and transferred to a stainless steel reaction vessel for crystallization at 170 ℃ for 2 days. After crystallization is finished, the solid crystallization product is centrifugally separated from mother liquor, and is washed by deionized water until the pH value of filtrate is reached<And 9, drying and roasting to obtain the SSZ-13 molecular sieve. It contains high aluminum pair content (Table 1), and has good NH after loading copper 3 SCR reactivity and hydrothermal stability (see Table 2).
Example 8
Mixing a certain mass of silica sol, LiOH, KOH and water, and then carrying out activation treatment at 160 ℃ for 5 hours, wherein the molar ratio of LiOH to KOH is 1: 6, OH - The concentration is 5 mol/L. Cooling the mixture to room temperature after activation, adding N, N, N-trimethyl-1-adamantyl ammonium hydroxide, NaY molecular sieve, SSZ-13 seed crystal and water, stirring to obtain initial gel,the molar composition of the initial gel was 150SiO 2 ：8Al 2 O 3 ：6MOH：3700H 2 O: 25SDA, the amount of seed added is 12 wt% of the total mass of the initial gel. The initial gel mixture was stirred well and transferred to a stainless steel reaction vessel and crystallized at 130 ℃ for 5 days. After crystallization is finished, the solid crystallization product is centrifugally separated from mother liquor, and is washed by deionized water until the pH value of filtrate is reached<9, drying and roasting to obtain the SSZ-13 molecular sieve. It contains high aluminum pair content (Table 1), and has good NH after loading copper 3 SCR reactivity and hydrothermal stability (see table 2).
Comparative example 1
Mixing a certain mass of silica sol, LiOH, NaOH, N, N, N-trimethyl-1-adamantyl ammonium hydroxide, a NaX molecular sieve, SSZ-13 seed crystals and water to obtain initial gel, wherein the molar ratio of LiOH to NaOH is 1: 10, molar composition of the initial gel of 180SiO 2 ：10Al 2 O 3 ：12MOH：4500H 2 O: 35SDA, the addition amount of the seed crystal accounts for 10 wt% of the total mass of the initial gel. The initial gel mixture is stirred evenly and then transferred to a stainless steel reaction kettle for crystallization for 5 days at 100 ℃. After crystallization is finished, the solid crystallization product is centrifugally separated from mother liquor, and is washed by deionized water until the pH value of filtrate is reached<9, drying and roasting to obtain the SSZ-13 molecular sieve. The X-ray diffraction results (see figure 1) show that the product contains a analcime heterophase, indicating that the silicon source, which was not activated by the base treatment, is less active and the reaction rate of the starting Y molecular sieve is not matched.
Comparative example 2
Mixing a certain mass of white carbon black, KOH and water, and treating at 200 ℃ for 1 hour to obtain OH - The concentration was 0.1 mol/L. Cooling the mixture to room temperature after activation, adding N, N, N-trimethyl-1-adamantane ammonium chloride, NaY molecular sieve, SSZ-13 seed crystal and water to obtain initial gel, wherein the molar composition of the initial gel is 100SiO 2 ：4Al 2 O 3 ：10MOH：3300H 2 O: 19SDA, the addition amount of the seed crystal accounts for 0.5 wt% of the total mass of the initial gel. The initial gel mixture was stirred well and transferred to a stainless steel reaction vessel for crystallization at 120 ℃ for 4 days. After crystallization is finished, the solid crystallization product is centrifugally separated from mother liquor, and is washed by deionized water until the pH value of filtrate is reached<9, dryingAnd roasting to obtain the SSZ-13 molecular sieve. X-ray diffraction showed SSZ-13 molecular sieve (see FIG. 1) with low aluminum content (Table 1), loaded with NH after copper loading 3 The SCR reactivity and hydrothermal stability were poor (see fig. 2).
TABLE 1 aluminum Pair content of SSZ-13 molecular sieves prepared in examples 1-8 and comparative example 2
TABLE 2 NH of fresh and aged samples of examples 2-8 3 SCR evaluation result data
TABLE 3 product yields for the examples and comparative examples
The product yields of examples 1-8 and comparative examples 1-2 were counted, and as shown in table 3, it can be seen from table 3 that the SSZ-13 molecular sieve prepared by the method of the present invention has a higher product yield.
The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the protection scope of the present invention.
Claims (9)
1. A process for the preparation of an aluminum pair enriched SSZ-13 molecular sieve comprising the steps of:
mixing a silicon source, alkali metal hydroxide and water, and activating to obtain an activated mixture;
mixing a template agent, a low-silicon molecular sieve, water and seed crystals, adding the activated mixture, and fully and uniformly stirring to obtain initial gel;
transferring the initial gel to a reaction kettle for crystallization, and centrifuging, washing, drying and roasting a product after crystallization to obtain the SSZ-13 molecular sieve;
the alkali metal hydroxide is a mixture of LiOH and any one of NaOH, KOH, RbOH and CsOH;
the low-silicon molecular sieve is any one of Na-type A, X, Y molecular sieves or other silicon-aluminum molecular sieves with the framework density smaller than SSZ-13.
2. The method for preparing the SSZ-13 molecular sieve rich in aluminum pairs according to claim 1, wherein the silicon source is any one of silica sol, white carbon black and sodium silicate; the molar content of LiOH in the alkali metal hydroxide is 1-50%.
3. The method for preparing the SSZ-13 molecular sieve rich in aluminum pairs according to claim 1, wherein the silicon source, the alkali metal hydroxide and the water are mixed and then activated at 90-200 ℃ for 1-12 hours.
4. The method of claim 1, wherein OH in the activation mixture is OH - The concentration of (b) is 0.1-6 mol/L.
5. The method of claim 1, wherein the template agent is any one of N, N, N-trimethyl-1-adamantylammonium hydroxide, N, N, N-trimethyl-1-adamantylammonium chloride, N, N, N-trimethyl-1-adamantylammonium bromide, N, N, N-trimethyl-1-adamantylammonium iodide.
6. The method for preparing the aluminum pair-enriched SSZ-13 molecular sieve according to claim 1, wherein the seed crystal is obtained by mechanical crushing, acid etching or alkali etching of the SSZ-13 molecular sieve; the addition amount of the seed crystal accounts for 0.1-15 wt% of the total mass of the initial gel.
7. The method for preparing an aluminum pair-enriched SSZ-13 molecular sieve according to claim 1, wherein the molar composition of the initial gel is (100-180) SiO 2 ：（1~10）Al 2 O 3 ：（5~15）MOH：（2000~4500）H 2 O: (5-35) SDA, wherein M is alkali metal, and SDA is a template agent.
8. The method for preparing the aluminum pair-enriched SSZ-13 molecular sieve according to claim 1, wherein the crystallization temperature of the initial gel is 100-180 ℃ and the crystallization time is 1-5 days.
9. The application of the SSZ-13 molecular sieve rich in aluminum pairs prepared according to any one of claims 1 to 8 is characterized in that the SSZ-13 molecular sieve rich in aluminum pairs is loaded with copper and then applied to ammonia selective catalytic reduction reaction to remove nitrogen oxides.
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