阅读说明：本技术 高产率Me-SSZ-98型分子筛材料、催化剂及应用 (High-yield Me-SSZ-98 type molecular sieve material, catalyst and application ) 是由 马江丽 于飞 杨冬霞 常仕英 赖慧龙 赵云昆 殷雪梅 王火印 朱敬芳 汪朝强 于 2021-08-27 设计创作，主要内容包括：高产率Me-SSZ-98型分子筛材料、催化剂及应用,本发明采用1,1-二甲基氮杂环己基氯化物作为反应模板剂,将模板剂溶于去离子水中搅拌均匀,采用强碱性羟基型阴离子作为交换树脂过柱子交换得到过滤溶液；加入二氧化硅源、氧化铝源,再加入M(OH)得到凝胶,将凝胶转入压力反应釜中进行水热晶化反应,将晶化液过滤洗涤,滤饼烘干制得SSZ-98分子筛原粉,将分子筛原粉加热、焙烧制得SSZ-98型分子筛材料。将分子筛材料加入盐溶液中离子交换后,过滤、干燥、焙烧,制得Me-SSZ-98型分子筛催化剂。本发明选择廉价的1,1-二甲基氮杂环己基氯化物为模板剂,有效地利用有机模板剂及合成体系中OH～(-1),大幅提高了SSZ-98型分子筛的产率和缩短了晶化时间。(The invention relates to a high-yield Me-SSZ-98 type molecular sieve material, a catalyst and application, wherein 1, 1-dimethyl aza cyclohexyl chloride is adopted as a reaction template agent, the template agent is dissolved in deionized water and uniformly stirred, and strong-basicity hydroxyl anion is adopted as exchange resin to pass through a column for exchange to obtain a filtering solution; adding silicon dioxide source and aluminum oxide source, adding M (OH) to obtain gel, transferring the gel into a pressure reaction kettle for hydrothermal crystallization reaction, filtering and washing the crystallized liquid, and filtering a filter cakeAnd drying to obtain SSZ-98 molecular sieve raw powder, heating the molecular sieve raw powder, and roasting to obtain the SSZ-98 molecular sieve material. Adding the molecular sieve material into a salt solution for ion exchange, filtering, drying and roasting to obtain the Me-SSZ-98 type molecular sieve catalyst. The invention selects cheap 1, 1-dimethyl aza cyclohexyl chloride as template agent, effectively utilizes organic template agent and OH in synthesis system ‑1 Greatly improves the yield of the SSZ-98 type molecular sieve and shortens the crystallization time.)

1. High-yield Me-SSZ-98 type molecular sieve material, which is characterized in that: the molecular sieve material is prepared by the following method steps:

(1) 1, 1-dimethyl aza cyclohexyl chloride is adopted as a reaction template agent, the template agent is dissolved in deionized water according to the solid-to-liquid ratio of 10-50 percent, and the mixture is uniformly stirred;

(2) adopting strong-alkaline hydroxyl type anions as exchange resin, filling the exchange resin into a chromatographic column, adding the solution prepared in the step (1) into the chromatographic column, and performing column exchange to obtain a filtered solution;

(3) dripping a silicon dioxide source into the filtering solution obtained in the step (2) and uniformly stirring;

(4) adding an alumina source into the solution obtained in the step (3) and uniformly stirring;

(5) adding M (OH) into the solution obtained in the step (4) to obtain gel, wherein M is one or a mixture of more than two of sodium, potassium and ammonium cations; the molar ratio of the reaction raw materials in the gel is as follows: SiO2₂/Al₂O₃＝15～80，M/Al₂O₃＝0.020～0.050，H₂O/Al₂O₃80-270 parts of organic template/Al₂O₃＝4.0-5.0；

(6) Transferring the gel prepared in the step (5) into an autogenous pressure reaction kettle with a polytetrafluoroethylene lining, and carrying out rotary crystallization for 3-24h at the temperature of 100-;

(7) after the hydrothermal crystallization reaction in the step (6) is finished, filtering and washing the crystallization liquid, and drying the filter cake at 80-160 ℃ for 1-24h to obtain SSZ-98 molecular sieve raw powder;

(8) and (4) heating the SSZ-98 molecular sieve raw powder prepared in the step (7) to 500-650 ℃, and roasting for 2-6h to prepare the required SSZ-98 type molecular sieve material.

2. A high yield Me-SSZ-98 type molecular sieve material according to claim 1, characterized in that: the silica-silicon source in step (3) includes but is not limited to orthosilicate, silica sol, and active SiO₂One or more of faujasite, Y zeolite, BEA zeolite and A zeolite.

3. A high yield Me-SSZ-98 type molecular sieve material according to claim 1, characterized in that: the alumina source in the step (4) includes but is not limited to one or more of activated alumina, aluminum isopropoxide, pseudoboehmite, faujasite, Y zeolite, BEA zeolite and A zeolite.

4. A high yield Me-SSZ-98 type molecular sieve material according to claim 1, characterized in that: and (3) regenerating the exchange resin used in the step (2) by using strong base for recycling.

5. The high-yield Me-SSZ-98 type molecular sieve catalyst prepared by using the high-yield Me-SSZ-98 type molecular sieve material as claimed in claim 1, 2 or 3, wherein 0.1-5% by mass of transition valence-change metal salt is dissolved in water to obtain a salt solution, the SSZ-98 type molecular sieve material prepared in the step (8) is added into the salt solution, ion exchange is carried out for 1-10h at the water temperature of 50-80 ℃, and then the Me-SSZ-98 type molecular sieve catalyst is prepared after filtration, drying and roasting.

6. The high yield Me-SSZ-98 molecular sieve catalyst according to claim 5, characterized in that: the transition valence-change metal salt comprises one or more of copper salt, iron salt and cerium salt.

7. The use of the high yield Me-SSZ-98 molecular sieve catalyst of claim 5 or 6 for selective catalytic reduction of nitrogen oxides in diesel exhaust emissions.

Technical Field

The invention relates to a high-yield Me-SSZ-98 type molecular sieve catalyst and a synthesis method thereof, wherein the molecular sieve can be applied to selective catalytic reduction of nitrogen oxides (NOx) in diesel engine exhaust emission.

Background

The diesel engine is widely applied to various road and non-road machines due to good dynamic property and economy, but the inherent oxygen-enriched combustion characteristic of the diesel engine causes serious NOx emission and serious influence on human health and ecological environment. In order to deal with the serious harm brought by NOx, strict emission regulations are set by all countries to control the emission of pollutants of diesel engines. From 7 and 1 of 2019, the national six-emission standard of heavy diesel engines is promulgated formally in China, and the instantaneous NOx emission value is required to be not more than 0.46 g/kWh. Selective catalytic reduction of nitrogen oxides (NH)₃SCR) technology is currently one of the main off-board means of reducing NOx emissions from diesel engines. NH (NH)₃The SCR technology generally adopts a molecular sieve as a supporter, is modified by transition valence-change metal, and is generally applied to the posterior places of the sixth country of diesel engines and the fourth country of non-road countriesIn the catalyst. However, in the operation process of the diesel engine, the water content is high, the environment is damp and hot, and when the DPF is triggered to regenerate, the instantaneous combustion temperature can reach above 650 ℃, so that the used molecular sieve material is required to have a special small-hole pore channel structure so as to improve the high NOx conversion rate, the water-resistant thermal stability and the durability of the catalyst. Small pore molecular sieves are an important class of crystalline materials used commercially, having unique crystal structures and ordered pore structures.

Molecular sieves are a class of microporous materials having a regular pore structure, classified by the structure commission of the international zeolite association according to the rules of the IUPA commission on zeolite nomenclature. According to this classification, framework-type and other structurally defined molecular sieves are designated by three-letter codes (e.g., ERI).

ERI framework-type materials typically comprise double six-ring (d6R) and eight-membered ring pore/channel units and cages. The ERI type molecular sieve catalyst has smaller pore diameter, comprises two types of SSZ-98 and ZSM-34, has better shape selectivity, is suitable for the hydrocarbon of C1-C4 to pass, and has shown important commercial value in Methanol To Olefin (MTO) catalysis. Aluminosilicate ERI is generally synthesized by hydrothermal crystallization methods, wherein the Structure Directing Agent (SDA) used is typically a complex organic molecule that induces the formation of the molecular shape and pattern of the zeolite framework by hydrothermal reactions. The SDA acts as a mold for molecular sieve formation, inducing the silica-alumina units to form a crystalline structure around them. After the hydrothermal reaction is complete, the SDA is typically removed from the crystalline structure, typically at elevated temperatures above 500 ℃, leaving behind porous aluminosilicate cages.

US2950925 first reported in 1960 the synthesis of aluminosilicate ERI zeolites, known as T-type zeolites, which produced T-type zeolites as intergrowths of ERI and OFF. US patents US9,409,786 and US9,416,017 disclose the synthesis of phase-pure SSZ-98 type molecular sieves using N, N' -dimethyl-1, 4-diazabicyclo [2.2.2] octane dications as structure directing agents. Chinese patent CN106470944B discloses the synthesis of pure phase SSZ-98 type molecular sieve using N, N' -dimethyl-1, 4-diazabicyclo [2.2.2] octane dication and 18-crown-6 as a dual template. Chinese patent CN108495815A discloses the synthesis of pure phase SSZ-98 type molecular sieves using a structure directing agent of one or more of 1, 1-diethylpyrrolidinium cation, 1-butyl-1-methylpiperidinium cation, 1-diethyl-4-methylpiperidinium cation and 8- (pyridin-2-yl) -5, 8-diazaspiro [4.5] decan-5-ium cation.

It is noteworthy that, although the complex organic templating agents described above are successful in synthesizing pure phase SSZ-98 type molecular sieves, the preparative crystallization process typically takes 3 to 7 days or more. In addition, the known templating agents described above are very expensive and constitute one of the most significant portions of the cost of producing SSZ-98 type molecular sieves. When the crystallization reaction is carried out using the above-mentioned known template, the yield is low (generally around 50%). Therefore, there is an urgent need for a template agent with high efficiency and cost effectiveness, which is suitable for the growth of the framework of the SSZ-98 type molecular sieve, can rapidly synthesize zeolite and improve the yield of the molecular sieve, thereby producing the Me-SSZ-98 type molecular sieve in batches and being widely applied to the selective catalytic reduction of nitrogen oxides, and has very important significance.

Disclosure of Invention

The invention aims to solve the problems in the prior art and provides a high-yield Me-SSZ-98 type molecular sieve catalyst and a synthesis method thereof.

The technical scheme adopted by the invention is as follows:

high yield Me-SSZ-98 type molecular sieve material prepared by the following method steps:

(1) 1, 1-dimethyl aza cyclohexyl chloride is adopted as a reaction template agent, the template agent is dissolved in deionized water according to the solid-to-liquid ratio of 10-50 percent, and the mixture is uniformly stirred;

(2) adopting strong-alkaline hydroxyl type anions as exchange resin, filling the exchange resin into a chromatographic column, adding the solution prepared in the step (1) into the chromatographic column, and performing column exchange on the solution by a 1-10 bed to obtain a filtered solution;

(3) dripping a silicon dioxide source into the filtering solution obtained in the step (2) and uniformly stirring;

(4) adding an alumina source into the solution obtained in the step (3) and uniformly stirring;

(5) to the step of(4) Adding M (OH) into the obtained solution to obtain gel, wherein M is one or a mixture of more than two of sodium, potassium and ammonium cations; the molar ratio of the reaction raw materials in the gel is as follows: SiO2₂/Al₂O₃＝15～80，M/Al₂O₃＝0.020～0.050，H₂O/Al₂O₃80-270 parts of organic template/Al₂O₃＝4.0-5.0；

(6) Transferring the gel prepared in the step (5) into an autogenous pressure reaction kettle with a polytetrafluoroethylene lining, and carrying out rotary crystallization for 3-24h at the temperature of 100-;

(7) after the hydrothermal crystallization reaction in the step (6) is finished, filtering and washing the crystallization liquid, and drying the filter cake at 80-160 ℃ for 1-24h to obtain SSZ-98 molecular sieve raw powder;

(8) and (4) heating the SSZ-98 molecular sieve raw powder prepared in the step (7) to 500-650 ℃, and roasting for 2-6h to prepare the required SSZ-98 type molecular sieve material.

Further, the silica-silicon source in the step (3) includes, but is not limited to, orthosilicate, silica sol, active SiO₂One or more of faujasite, Y zeolite, BEA zeolite and A zeolite.

Further, the alumina source in the step (4) includes, but is not limited to, one or more of activated alumina, aluminum isopropoxide, pseudoboehmite, faujasite, Y zeolite, BEA zeolite, and a zeolite.

Further, the exchange resin used in the step (2) is regenerated by strong base and recycled.

The high-yield Me-SSZ-98 type molecular sieve catalyst prepared by adopting the high-yield Me-SSZ-98 type molecular sieve material is prepared by dissolving transition valence-change metal salt with the mass ratio of 0.1-5% in water to obtain a salt solution, adding the SSZ-98 type molecular sieve material prepared in the step (8) into the salt solution, carrying out ion exchange at the water temperature of 50-80 ℃ for 1-10h, filtering, drying and roasting to obtain the Me-SSZ-98 type molecular sieve catalyst.

Further, the transition valence-variable metal salt includes, but is not limited to, one or more of copper salt, iron salt and cerium salt.

The high-yield Me-SSZ-98 type molecular sieve catalyst is applied to selective catalytic reduction of nitrogen oxides in the exhaust emission of diesel engines.

Compared with the prior art, the method has the following advantages:

(1) 1, 1-dimethyl aza cyclohexyl chloride with low price is selected as a reaction template, so that the manufacturing cost of the molecular sieve is effectively reduced;

(2) by introducing strongly basic hydroxyl type anion exchange resin, the-N of stronger tetrahedral ammonium salt functional group is introduced⁺(CH₃)₃At OH^-1In the form of a mixture of-N⁺(CH₃)₃OH^-Hydroxide ions in the molecular sieve are released rapidly to decompose the original structures of the silicon source, the aluminum source and the initial molecular sieve, an ERI framework is rapidly generated through the induction of a template agent, and the crystallization time is shortened;

(3) by the formulaThe number of moles of chloride ions contained in the reaction template (in the above formula, M represents the mass of the added 1, 1-dimethylazacyclohexylchloride in g; M represents the molecular mass of 1, 1-dimethylazacyclohexylchloride in g/mol) was calculated in terms of Cl^-1:OH^-1Adding required strongly basic anion resin into the mixture according to the molar ratio of 1 to 10, and converting Cl^-1. Since the conversion reaction is a reversible reaction, OH in the strongly basic hydroxyl type anion exchange resin^-1Ion and Cl in 1, 1-Dimethylazepine cyclohexyl chloride^-1There is a competing reaction. When OH is present^-1When the amount of ion introduced is too low, Cl^-1Can not be completely converted, often leads to the doping of a large amount of amorphous products and mixed crystals in the synthesized product, and seriously influences the crystallinity of the SSZ-98 framework, thereby leading to the synthesis failure or seriously weakening the NOx treatment capability of the molecular sieve catalyst. When OH is present^-1OH in the tetrahedral ammonium salt function converted when the ion introduction is excessive^-1Is easy to be substituted by chloride in Cl type strong base resin with stronger alkalinity, thereby causing incomplete conversion. Simultaneously, reacting the crystallized solutionExcess OH in^-1The yield of SSZ-98 type molecular sieve is reduced.

Drawings

FIG. 1 is an XRD spectrum of the catalyst provided in example 1 of the present invention;

FIG. 2 is an SEM image of a catalyst provided in example 1 of the present invention;

FIG. 3 is a graph comparing NOx conversion efficiencies of fresh catalysts of examples 1, 2, 3, 4, 5, 1, 2, 3, 4, 5 of the present invention;

FIG. 4 is a graph comparing the NOx conversion efficiency of aged catalysts of example 1, example 2, example 3, example 4, example 5, comparative example 1, comparative example 2, comparative example 3, comparative example 4, and comparative example 5 of the present invention;

Detailed Description

The invention will be further elucidated with reference to the drawings and examples. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments which are the same as or equivalent to the embodiments of the present invention obtained by those skilled in the art without any inventive work belong to the protection scope of the present invention.

A synthetic method of a high-yield Me-SSZ-98 type molecular sieve catalyst is characterized by comprising the following steps: the method comprises the following steps:

(1) 1, 1-dimethyl aza cyclohexyl chloride is adopted as a reaction template agent, the template agent is dissolved in deionized water according to the solid-to-liquid ratio of 10-50 percent, and the mixture is uniformly stirred;

(2) adopting strong-alkaline hydroxyl type anion as exchange resin, filling the exchange resin into a chromatographic column, adding the solution prepared in the step (1) into the chromatographic column, and performing column exchange on the solution by a bed of 1-10 to obtain a filtering solution. The used exchange resin can be regenerated by strong base and recycled, so that the production cost is further reduced compared with the prior art;

(3) dripping a silicon dioxide source into the filtering solution obtained in the step (2) and uniformly stirring; the silica silicon source includes but is not limited toOrthosilicate, silica sol, active SiO₂One or more of faujasite, BEA zeolite, Y-type zeolite and A zeolite;

(4) adding an alumina source into the solution obtained in the step (3) and uniformly stirring; the alumina source comprises one or more of activated alumina, aluminum isopropoxide, pseudo-boehmite, faujasite, BEA zeolite, Y-type zeolite and A zeolite;

(5) adding M (OH) into the solution obtained in the step (4) to obtain gel, wherein M is one or a mixture of more than two of sodium, potassium and ammonium cations; the molar ratio of the reaction raw materials in the gel is as follows: SiO2₂/Al₂O₃＝15～80，M/Al₂O₃＝0.020～0.050，H₂O/Al₂O₃80-270 parts of organic template/Al₂O₃＝4.0～5.0；

(6) Transferring the gel prepared in the step (5) into an autogenous pressure reaction kettle with a polytetrafluoroethylene lining, and carrying out rotary crystallization for 3-24h at the temperature of 100-;

(7) after the hydrothermal crystallization reaction in the step (6) is finished, filtering and washing the crystallization liquid, and drying the filter cake at 80-160 ℃ for 1-24h to obtain SSZ-98 molecular sieve raw powder;

(8) and (4) heating the SSZ-98 molecular sieve raw powder prepared in the step (7) to 500-650 ℃, and roasting for 2-6h to prepare the required SSZ-98 type molecular sieve material.

Dissolving transition valence-change metal salt with the mass ratio of 0.1-5% in water to obtain a salt solution, adding the SSZ-98 type molecular sieve material prepared in the step (8) into the salt solution, performing ion exchange for 1-10h at the water temperature of 50-80 ℃, filtering, drying and roasting to obtain the Me-SSZ-98 type molecular sieve catalyst; the transition valence-change metal salt includes but is not limited to one of copper salt, iron salt and cerium salt or a mixture of any more than 2.

The molecular sieve catalyst prepared by the method can be applied to selective catalytic reduction of nitrogen oxides in the exhaust emission of diesel engines.

The raw materials used in the present invention such as 1, 1-dimethyl azacyclohexyl chloride, strongly basic hydroxyl type anion, silica silicon source, alumina source, M (OH) are all available from the market. The autogenous pressure reaction kettle with the polytetrafluoroethylene lining is equipment in the prior art.

Example 1

44.6g of 1, 1-dimethyl azacyclohexyl chloride is weighed and dissolved in 90g of deionized water, and after the chloride is completely dissolved, the solution is transferred to a 300 ml basic hydroxyl type anion resin chromatographic column to pass through a 5-column bed, and the filtered solution is reserved. 74.5g of silica sol (LuDOX-40) is added into the filtering solution drop by drop and stirred vigorously, then 1.62g of activated alumina is added, and stirring is continued for 3 hours until the silicon source and the aluminum source are completely dissolved. 6.2g of KOH solution with the mass concentration of 45 percent is weighed and added into the solution with the silicon source and the aluminum source completely dissolved, and the gel is obtained after even stirring. And (3) transferring the gel into an autogenous pressure reaction kettle with a polytetrafluoroethylene lining, performing rotary crystallization at 180 ℃ for 8 hours, performing hydrothermal crystallization reaction, after the reaction is finished, placing the crystallized liquid in a centrifuge for separation and filtration, and washing until the filtrate is neutral. And (3) drying the filter cake at a constant temperature of 120 ℃ for 10 hours to prepare SSZ-98 molecular sieve raw powder, and roasting the prepared SSZ-98 molecular sieve raw powder in a muffle furnace at a temperature of 600 ℃ for 5 hours to prepare SSZ-98 molecular sieve powder. The framework structure of the blank molecular sieve was characterized by XRD and the results are shown in FIG. 1. The morphology was characterized by SEM and the results are shown in figure 2.

34g of copper acetate was weighed out and dissolved in 1023g of deionized water, and stirred well. Adding the blank SSZ-98 type molecular sieve into the precursor aqueous solution according to the solid-to-liquid ratio of 40%, continuing stirring in a water bath for 5h, and grinding until the D90 is 7.8 mu m. The slurry is coated on a honeycomb ceramic carrier according to the dry weight mass of 180g/L of the slurry. After drying in a drying furnace at 120 ℃, the sample is calcined in a muffle furnace at 550 ℃ for 3h to obtain a sample 1.

Example 2

Weighing 11.06g of 1, 1-dimethyl azacyclohexyl chloride and dissolving in 44g of deionized water; after completely dissolving, transferring into 100 ml of strongly basic hydroxyl type anion resin, placing in a chromatographic column, passing through column 4 bed, retaining the filtrate, and adding 1gY type zeolite (SiO) into the filtrate₂/Al₂O₃30) and stirring uniformly until the silicon source and the aluminum source are completely dissolved. Further addition of 4.4gNaOH solution with a mass concentration of 45% and vigorously stirring the gel until homogeneous. The gel was capped and placed in an autoclave reactor and subjected to hydrothermal reaction at 200 ℃ for 6h at 30 rpm. After the reaction is finished, separating and filtering the crystallization liquid, washing until the filtered water is neutral, drying the solid filter cake at the constant temperature of 80 ℃ for 24h, and calcining at the temperature of 550 ℃ in a muffle furnace for 4h to obtain SSZ-98 molecular sieve powder.

34g of copper acetate was weighed out and dissolved in 1023g of deionized water, and stirred well. Adding the blank SSZ-98 type molecular sieve into the precursor aqueous solution according to the solid-to-liquid ratio of 40%, continuing stirring in a water bath for 5h, and grinding until the D90 is 7.8 mu m. The slurry is coated on a honeycomb ceramic carrier according to the dry weight mass of 180g/L of the slurry. After drying in a drying furnace at 120 ℃, the sample was calcined in a muffle furnace at 550 ℃ for 3 hours to obtain sample 2.

Example 3

Weighing 20g of 1, 1-dimethyl azacyclohexyl chloride, dissolving in 200g of deionized water, transferring to 500 ml of basic hydroxyl type anion resin chromatographic column to pass through a column 5 bed after the chloride is completely dissolved, and keeping the filtrate. And (2) dropwise adding 27g of active silica into the filtrate, stirring the mixture vigorously and uniformly, adding 3.06g of active alumina into the filtrate, stirring the mixture for 1h until the silicon source and the aluminum source are completely dissolved, weighing 1.02g of 50% ammonium hydroxide solution by mass concentration, adding the ammonium hydroxide solution into the completely dissolved silicon source and aluminum source solution, and stirring the mixture uniformly to obtain gel. And transferring the gel into a hydrothermal reaction kettle with a polytetrafluoroethylene lining, and carrying out rotary crystallization at 100 ℃ for 24 hours. After the reaction is finished, the crystallized liquid is placed in a centrifuge for separation and filtration, and the filtrate is washed until the filtrate is neutral. And (3) drying the filter cake at a constant temperature of 160 ℃ for 1h, and roasting in a muffle furnace at a temperature of 650 ℃ for 2h to obtain SSZ-98 molecular sieve powder.

34g of copper acetate was weighed out and dissolved in 1023g of deionized water, and stirred well. Adding the blank SSZ-98 type molecular sieve into the precursor aqueous solution according to the solid-to-liquid ratio of 40%, continuing stirring in a water bath for 5h, and grinding until the D90 is 7.8 mu m. The slurry is coated on a honeycomb ceramic carrier according to the dry weight mass of 180g/L of the slurry. After drying in a drying furnace at 120 ℃, the sample was calcined in a muffle furnace at 550 ℃ for 3 hours to obtain sample 3.

Example 4

53.9g of 1, 1-dimethyl azacyclohexyl chloride was weighed out and dissolved in 108g of deionized water, and after complete dissolution, the solution was transferred to a 1 liter basic hydroxyl type anion resin chromatographic column and passed through column 1 bed, and the filtrate was retained. And (3) dropwise adding 90g of silica sol into the filtrate, stirring the mixture vigorously, then adding 4.96g of aluminum isopropoxide, and stirring the mixture for 2 hours until the silicon source and the aluminum source are completely dissolved. 1.92g of 50% sodium hydroxide solution and 4.04g of 50% potassium hydroxide solution were weighed and added to the above-mentioned solution in which the silicon source and the aluminum source were completely dissolved, to obtain a gel. And transferring the gel into a hydrothermal reaction kettle with a polytetrafluoroethylene lining, and carrying out rotary crystallization at 180 ℃ for 3 hours. After the reaction is finished, the crystallized liquid is placed in a centrifuge for separation and filtration, and the filtrate is washed until the filtrate is neutral. And (3) drying the filter cake at a constant temperature of 150 ℃ for 1h, and roasting in a muffle furnace at a temperature of 650 ℃ for 4 h.

34g of copper acetate was weighed out and dissolved in 1023g of deionized water, and stirred well. Adding the blank SSZ-98 type molecular sieve into the precursor aqueous solution according to the solid-to-liquid ratio of 40%, continuing stirring in a water bath for 5h, and grinding until the D90 is 7.8 mu m. The slurry is coated on a honeycomb ceramic carrier according to the dry weight mass of 180g/L of the slurry. After drying in a drying furnace at 120 ℃, the sample was calcined in a muffle furnace at 550 ℃ for 3 hours to obtain sample 4.

Example 5

Weighing 11.06g of 1, 1-dimethyl azacyclohexyl chloride, dissolving in 44g of deionized water, transferring to 100 ml of strongly basic hydroxyl type anion resin after completely dissolving, placing in a chromatographic column, passing through a column 10 bed, retaining the filtrate, and adding 1gY type zeolite (SiO) into the filtrate₂/Al₂O₃30) and stirring uniformly until the silicon source and the aluminum source are completely dissolved. Then, 1.5g, 2.1g, and 1.3g of each of NaOH, KOH, and ammonium hydroxide solutions having a mass concentration of 45% were added to the solutions in which the silicon source and the aluminum source were completely dissolved, and stirred vigorously until uniform, to obtain a gel. The gel was capped and placed in an autoclave reactor and subjected to hydrothermal reaction at 150 ℃ for 13h at 30 rpm. After the reaction is finished, washing the crystallization liquid until the filtered water is neutral, drying the solid filter cake at 80 ℃ for 24h,and calcining the mixture for 6 hours in a muffle furnace at 500 ℃ to prepare SSZ-98 molecular sieve powder.

34g of copper acetate was weighed out and dissolved in 1023g of deionized water, and stirred well. Adding the blank SSZ-98 type molecular sieve into the precursor aqueous solution according to the solid-to-liquid ratio of 40%, continuing stirring in a water bath for 5h, and grinding until the D90 is 7.8 mu m. The slurry is coated on a honeycomb ceramic carrier according to the dry weight mass of 180g/L of the slurry. After drying in a drying furnace at 120 ℃, the sample is calcined in a muffle furnace at 550 ℃ for 3h to obtain a sample 5.

Comparative example 1

The SSZ-98 type molecular sieve material is prepared by adopting the prior art. 0.74g of 45% KOH solution, 4.57g of deionized water and 0.21g of 50% aluminum hydroxide solution were mixed together in a polytetrafluoroethylene liner. Then, 1.85g of 19% 1, 1-dimethylpiperidinium solution was added to the mixture. Then, 2.00g of silica sol (AS-40) was added to the mixture, and the gel was stirred until it became homogeneous. The lined vessel was then capped and placed in an autoclave reactor. The autoclave was placed in an oven and heated at 140 ℃ for 5 days. The solid product was recovered from the filtrate by filtration, washed with deionized water and dried at 95 ℃ and calcined at 550 ℃ for 5 hours to prepare an SSZ-98 type molecular sieve.

34g of copper acetate was weighed out and dissolved in 1023g of deionized water, and stirred well. Adding the blank SSZ-98 type molecular sieve into the precursor aqueous solution according to the solid-to-liquid ratio of 40%, continuing stirring in a water bath for 5h, and grinding until the D90 is 7.8 mu m. The slurry is coated on a honeycomb ceramic carrier according to the dry weight mass of 180g/L of the slurry. After drying in a drying furnace at 120 ℃, the sample was calcined in a muffle furnace at 550 ℃ for 3 hours to obtain sample 6.

Comparative example 2

The SSZ-98 type molecular sieve material is prepared by adopting the prior art. 1.81 g of 45% aqueous NaOH solution was weighed into a glass beaker, 11.14 g of deionized water and 2g of Y-type molecular sieve (Si/Al ratio: 60) were added to the glass beaker, and the glass beaker was placed on a magnetic stirrer and stirred vigorously. After the Y-type molecular sieve is completely melted, 9.2 g of 10% 1-butyl-1-methylpiperidinium cation solution is added into the solution, stirred for 3h and then transferred into a reaction kettle with a polytetrafluoroethylene lining. Hydrothermal reaction at 150 deg.c for 120 hr at 30 rpm. And after the reaction is stopped, filtering and washing the crystallization liquid until washing water is neutral, placing a filter cake at 120 ℃ for overnight drying, and calcining at 550 ℃ for 4 hours to prepare the SSZ-98 type molecular sieve.

34g of copper acetate was weighed out and dissolved in 1023g of deionized water, and stirred well. Adding the blank SSZ-98 type molecular sieve into the precursor aqueous solution according to the solid-to-liquid ratio of 40%, continuing stirring in a water bath for 5h, and grinding until the D90 is 7.8 mu m. The slurry is coated on a honeycomb ceramic carrier according to the dry weight mass of 180g/L of the slurry. After drying in a drying furnace at 120 ℃, the sample was calcined in a muffle furnace at 550 ℃ for 3 hours to obtain sample 7.

Comparative example 3

The SSZ-98 type molecular sieve material is prepared by adopting the prior art. 0.80g of a 45% KOH solution, 11.06g of a 20.2% N, N' -dimethyl-1, 4-diazabicyclo [2.2.2] octane dication solution and 2.00g of Y-zeolite (SiO2/Al2O3 ═ 60) were mixed in a Teflon liner. The resulting gel was stirred until it became homogeneous. The liner was capped and placed in a stainless steel autoclave reactor. The autoclave was then placed in an oven heated at 150 ℃ for 3 days. The solid product was recovered from the cooled reactor by centrifugation, washed with deionized water and dried at 95 ℃ and calcined at 550 ℃ for 5h to produce a molecular sieve type SSZ-98.

34g of copper acetate was weighed out and dissolved in 1023g of deionized water, and stirred well. Adding the blank SSZ-98 type molecular sieve into the precursor aqueous solution according to the solid-to-liquid ratio of 40%, continuing stirring in a water bath for 5h, and grinding until the D90 is 7.8 mu m. The slurry is coated on a honeycomb ceramic carrier according to the dry weight mass of 180g/L of the slurry. After being dried in a drying furnace at 120 ℃, the sample is calcined in a muffle furnace at 550 ℃ for 3h to prepare a sample 8.

Comparative example 4

The SSZ-98 type molecular sieve material is prepared by adopting the prior art. According to a molar ratio of 1.63RBr2 (hexamethonium bromide): the molar ratio of reactants of 7.8KOH:0.8Al2O3:16SiO2:258H2O, aluminum sec-butoxide is dissolved in KOH solution, and the solution of hexamethonium bromide is added dropwise and stirred uniformly. Then slowly adding colloidal silica and deionized water, and vigorously stirring to form the aluminosilicate gel. The gel is placed in an oven and aged for 20 hours at the temperature of 95 ℃, and then placed in a stainless steel autoclave reactor. The autoclave was then placed in an oven heated at 150 ℃ for 3 days. The solid product was recovered from the cooled reactor by centrifugation, washed with deionized water and dried at 95 ℃ and calcined at 550 ℃ for 5h to produce a molecular sieve type SSZ-98.

34g of copper acetate was weighed out and dissolved in 1023g of deionized water, and stirred well. Adding the blank SSZ-98 type molecular sieve into the precursor aqueous solution according to the solid-to-liquid ratio of 40%, continuing stirring in a water bath for 5h, and grinding until the D90 is 7.8 mu m. The slurry is coated on a honeycomb ceramic carrier according to the dry weight mass of 180g/L of the slurry. After drying in a drying furnace at 120 ℃, the sample was calcined in a muffle furnace at 550 ℃ for 3 hours to obtain sample 9.

Comparative example 5

The SSZ-98 type molecular sieve material is prepared by adopting the prior art. 20g of 1, 1-diethyl-4-methylpiperidinium cation are weighed out and dissolved in 24g of deionized water, and after complete dissolution, 27g of active silica are added dropwise to the above filtrate with vigorous stirring. After the gel was stirred well, 3.06g of activated alumina was added thereto and stirred for 1 hour. 1.02g of 50% ammonium hydroxide solution was weighed into the gel and stirred vigorously until the silicon source and the aluminum source were completely dissolved. And transferring the gel into a hydrothermal reaction kettle with a polytetrafluoroethylene lining, and carrying out rotary crystallization at 200 ℃ for 144 h. After the reaction is finished, the crystallized liquid is placed in a centrifuge for separation and filtration, and the filtrate is washed until the filtrate is neutral. And (3) drying the filter cake at a constant temperature of 150 ℃, and roasting for 4 hours in a muffle furnace at a temperature of 650 ℃ to prepare the SSZ-98 type molecular sieve.

34g of copper acetate was weighed out and dissolved in 1023g of deionized water, and stirred well. Adding the blank SSZ-98 type molecular sieve into the precursor aqueous solution according to the solid-to-liquid ratio of 40%, continuing stirring in a water bath for 5h, and grinding until the D90 is 7.8 mu m. The slurry is coated on a honeycomb ceramic carrier according to the dry weight mass of 180g/L of the slurry. After drying in a drying furnace at 120 ℃, the sample is calcined in a muffle furnace at 550 ℃ for 3h to obtain a sample 10.

Measuring the pH value of the gel before sample crystallization by using a pH instrument; by using N₂Ratio of physical adsorption measurementSurface area, pore volume, pore size, the results are shown in the following table:

as can be seen from the results of the above table test, OH is rapidly released through the hydroxyl strongly basic anion resin by using 1, 1-dimethyl azacyclohexyl chloride as a template agent^-1And then, the synthesis time of the traditional SSZ-98 type molecular sieve is shortened from 150 hours to 6-13 hours, and the yield of the molecular sieve is improved from 45 percent to 95 percent. The strong alkaline reaction environment causes silicate to deposit on the surface of the formed molecular sieve framework, thereby leading the SSZ-98 type molecular sieve pore wall structure to be more complete. Higher specific surface area is NH₃The SCR reaction provides more reaction contact surface, and the catalyst reaction activity is improved.

The catalytic activity of the catalysts prepared in examples 1 to 5 and comparative examples 1 to 5 is evaluated, and the NOx conversion efficiency of the fresh catalyst and the catalyst after hydrothermal aging at different temperatures is specifically considered, and the specific method is as follows:

1) the hydrothermal aging of the catalyst adopts the following method:

cutting the coated catalyst into small samples with the specification of phi 25.4mm multiplied by 76.2mm, placing the small samples in a multifunctional atmosphere aging bench reactor, raising the temperature of the reactor to 800 ℃, stabilizing for 15min, adjusting an air inlet flow meter, and keeping the temperature for 80000h^-1At space velocity, [ O ] is introduced₂]＝14％，[CO₂]＝5％，[H₂O]＝10％，N₂Balancing gas, keeping constant temperature and stabilizing for 16 h.

2) The NOx conversion efficiency of the catalyst was measured by the following method:

the coated catalyst was cut into small pieces of 25.4mm phi by 76.2mm phi and placed in a quartz tube reactor. After the temperature of the reactor is raised to 500 ℃ and activated for 2h, the reaction space velocity is designed to be 60,000h^-1Introduction of [ NO ]]＝500ppm,[NH₃]＝500ppm，[O₂]＝5％，[H₂O]＝10％，[CO₂]＝8％，N₂Balancing qi. Setting the temperature of the reactor, respectively measuring the components and the content of the tail gas at the outlet end of the reactor at the inlet temperature of the catalyst of 550 ℃, 500 ℃, 450 ℃, 400 ℃, 350 ℃, 300 ℃, 250 ℃, 200 ℃ and 175 ℃, and calculating to obtain the NOx conversion efficiency. NO, NO₂、NH₃And N₂And measuring the O gas by adopting an infrared gas cell.

The results of the catalytic activity evaluation of the catalyst are shown in fig. 3 and 4. FIG. 3 is a graph comparing NOx conversion efficiencies of fresh catalysts of examples 1, 2, 3, 4, 5, 1, 2, 3, 4, 5 of the present invention; FIG. 4 is a graph comparing NOx conversion efficiencies of heat-aged catalysts of example 1, example 2, example 3, example 4, example 5, comparative example 1, comparative example 2, comparative example 3, comparative example 4, and comparative example 5 of the present invention. As can be seen from the graphs in FIGS. 3 and 4, after the 1, 1-dimethyl azacyclohexyl chloride is selected as the template agent and used together with the hydroxyl strongly basic anion resin, the activity of the prepared Cu-SSZ-98 type molecular sieve is improved by more than 5 percent compared with the low temperature activity of the traditional method, the NOx conversion efficiency can be maintained by more than 98 percent at the temperature of 250-500 ℃, and the reaction window of the SCR catalyst is greatly widened compared with the traditional preparation method; in addition, the Cu-SSZ-98 type molecular sieve prepared by the method has stronger hydrothermal stability, and the average degradation amount is less than 5 percent after hydrothermal aging for 16 hours at 800 ℃, thereby providing an application basis for national six and stricter emission control.

Dissolving transition valence-change metal salt with the mass ratio of 0.1-5% in water to obtain a salt solution, adding the SSZ-98 type molecular sieve material prepared in the embodiment 1-5 into the salt solution, performing ion exchange at the water temperature of 50-80 ℃ for 1-10h, filtering, drying and roasting to obtain the Me-SSZ-98 type molecular sieve catalyst. The transition metal salts include, but are not limited to, copper salts, iron salts, cerium salts, and combinations thereof.

All percentages referred to in the present invention are percentages by mass, unless otherwise indicated.

The invention uses cheap 1, 1-dimethyl aza cyclohexyl chloride as reaction template agent,by introducing strongly basic hydroxyl type anion exchange resin, the-N of stronger tetrahedral ammonium salt functional group is introduced⁺(CH₃)₃In the oxyhydrogen form, reacting-N⁺(CH₃)₃Hydroxide ions in OH-are quickly released to decompose the silicon source, the aluminum source and the original structure of the initial molecular sieve, and an ERI framework is quickly generated through the induction of a template agent. By strictly controlling OH in strong alkaline environment of the crystallization liquid^-1The introduced amount improves the yield of the SSZ-98 type molecular sieve material to over 90 percent. The prepared Me-SSZ-98 type molecular sieve catalyst has the characteristics of higher specific surface area, smaller crystal size, larger micropore volume, higher hydrothermal resistance and the like.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.