PREPARATION AND APPLICATION OF 4-METHYL-5-VINYLTHIAZOLYL POLYMERIC IONIC LIQUID

Abstract

This invention belongs to the technical field of green preparation of environmentally friendly catalysts, and discloses a preparation method and application of mesoporous FeCu—ZSM-5 molecular sieve, in particular to a method for synthesizing mesoporous FeCu—ZSM-5 molecular sieve by one-pot method and the application in selective catalytic reduction (SCR) denitration reaction. This invention firstly proposes to combine the two calcinations after demolding and ion exchange into one, that is, the original powder is directly calcined to prepare a FeCu—ZSM-5 molecular sieve. The molecular sieve has several advantages such as window with wide temperature window, low cost, good hydrothermal stability and high SCR denitrification activity. Besides, the synthesis process does not use a (large) pore template, nor does it use a post-treatment method to construct the mesopores. Therefore, the method of the invention not only has the advantages of simple process, simple operation, but also good economic and environmental benefits.

Claims

1. A mesoporous FeCu—ZSM-5 molecular sieve, comprising: deionized water, aluminum source, silicon source, iron source, copper source, acid source and templating agents; the content of Fe2O3 in the molecular sieve is 0.1˜10% of the total weight of the molecular sieve, wherein the content of Fe in skeleton accounts for more than 95% of the total iron content, and is evenly distributed in the framework; the CuO content in the molecular sieve is 0.1˜10% of the total weight of the molecular sieve, wherein the content of Cu2+ accounts for more than 90% of the total copper content, and is evenly distributed on the inner surface of the molecular sieve.

2. A process for producing mesoporous FeCu—ZSM-5 molecular sieve, comprising: a chemical reagent synthesis method or a mineral synthesis method.

3. The process according to claim 2, wherein the chemical reagent synthesis method specifically includes the following steps: (1) the deionized water, aluminum source, silicon source, iron source, copper source and templating agent are uniformly mixed under stirring conditions at 20-90° C., wherein the molar ratio of each substance in the synthetic system is SiO.sub.2/Al.sub.2O.sub.3=10˜∞, SiO.sub.2/Fe.sub.2O.sub.3=10˜350, SiO.sub.2/CuO=10˜150, Na.sub.2O/SiO.sub.2=0.1˜0.5, H.sub.2O/SiO.sub.2=10˜50, templating agent/SiO.sub.2=0.01˜0.5; after mixing, add the acid source to adjust the system pH to 5˜13 to carry out the first aging, then add the acid source again, adjust the system pH to 5˜13 to carry out the second aging, that is, obtain the aging gel, (2) the aged gel obtained in the step (1) is transferred to a Teflon-lined reaction kettle for sealing crystallization, after crystallization, the product is cooled, filtered to remove the mother liquid, and the filter cake is washed with deionized water to neutrality, dried to obtain a solid, and then which the solid is passed through ion-exchange, filtered, washed, and dried to obtain a powder; wherein the drying condition is 80-150° C., drying overnight; (3) the powder obtained in the step (2) is placed in a muffle furnace and calcined to obtain a mesoporous FeCu—ZSM-5 molecular sieve.

4. The process according to claim 3, wherein the iron source is one or more of ferric nitrate, ferric chloride and ferric sulfate, the copper source is one or more of copper nitrate, copper nitrate trihydrate, copper nitrate nonahydrate and copper chloride dihydrate, the acid source is one or more of 2-Hydroxy-1,2,3-propanetricarboxylic acid, sulfurous acid, nitrous acid, sulfuric acid, hydrochloric acid, nitric acid, oxalic acid, acetic acid, the silicon source is one or more of water glass, silica sol, tetraethyl orthosilicate, solid silica gel, the aluminum source is one or more of sodium aluminate and aluminum sulfate, the templating agent is tetraoctyl ammonium bromide, tetrabutylammonium bromide, CTMAB, tetrapropylammonium hydroxide, tetrapropylammonium bromide, hexylene glycol, butylamine, ethylamine.

5. The process according to claim 2, wherein the mineral synthesis method specifically includes the following steps: (1) mineral activation: aluminum source, silicon source, iron source and copper source are activated respectively; (2) the activated mineral is mixed with sodium hydroxide, deionized water and seed crystals, wherein the molar ratio of each substance in the synthetic system is SiO.sub.2/Al.sub.2O.sub.3=10˜∞, SiO.sub.2/Fe.sub.2O.sub.3=10˜350, SiO.sub.2/CuO=10˜150, Na.sub.2O/SiO.sub.2=0.1˜0.5, H.sub.2O/SiO.sub.2=10˜50, templating agent/SiO.sub.2=0.01˜0.5; after mixing, add the acid source to adjust the system pH to 5˜13 to carry out aging, that is, obtain the aging gel, (3) the aged gel obtained in the step (2) is transferred to a Teflon-lined reaction kettle for sealing crystallization, after crystallization, the product is cooled, filtered to remove the mother liquid, and the filter cake is washed with deionized water to neutrality, dried to obtain a solid, and then which the solid is passed through ion-exchange, filtered, washed, and dried to obtain a powder, wherein the drying condition is 80-150° C., drying overnight; (4) the powder obtained in the step (2) is placed in a muffle furnace and calcined to obtain a mesoporous FeCu—ZSM-5 molecular sieve.

6. The process according to claim 5, wherein the iron source is one or more of bauxite, diatomaceous earth, rectorite, pyrite, mica hematite, and red mud, the copper source is one or more of magnetite, malachite, copper blue, and chalcopyrite, the acid source is one or more of 2-Hydroxy-1,2,3-propanetricarboxylic acid, sulfurous acid, nitrous acid, sulfuric acid, hydrochloric acid, nitric acid, oxalic acid, acetic acid, the silicon source is one or two of bauxite, diatomaceous earth, rectorite, natural zeolite or opal, the aluminum source is one or more of mica, alumite, bauxite, diatomaceous earth, rectorite, natural zeolite, the templating agent is tetraoctyl ammonium bromide, tetrabutylammonium bromide, CTMAB, tetrapropylammonium hydroxide, tetrapropylammonium bromide, hexylene glycol, butylamine, ethylamine.

7. The process according to claim 3 or claim 5, wherein aging is carried out at 60-90° C. for 2-12 h; the crystallization is carried out at 100-190° C. for 12-96 h.

8. The process according to claim 3 or claim 5, wherein the method for ion-exchange is as follows: mixing the dried solid with 0.1˜2 M NH.sub.4Cl solution according to a mass ratio of 1:10 to 1:30 for ion exchange, and heating and stirring at 10˜80° C. for 3˜8 h.

9. The process according to claim 3 or claim 5, wherein the calcination is carried out at 500˜600° C. for 4˜10 h.

10. The application of mesoporous FeCu—ZSM-5 molecular sieve according to any of the claims 1-9 in the selective catalytic reduction of nitrogen oxides.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0043] FIG. 1 is an X-ray diffraction (XRD) spectrum of a FeCu—ZSM-5 molecular sieve prepared in Example 1 of the present invention.

[0044] FIG. 2 is an N.sub.2 adsorption-desorption isotherm of the FeCu—ZSM-5 molecular sieve prepared in Example 1 of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0045] The embodiments of the present invention and the beneficial effects thereof are described in detail below by way of specific examples, which are intended to provide a better understanding of the nature and features of the present invention.

Embodiment 1

[0046] 1.32 g Fe(NO.sub.3).sub.3.9H.sub.2O, 0.26 g Cu(NO.sub.3).sub.2.3H.sub.2O, 36.55 g H.sub.2O, 1.473 g TPABr, 14.18 g water glass (27.6 wt % SiO.sub.2), 2.2 g 2-hydroxy-propanetricarboxylic acid were mixed in the beaker. Then adjust the pH to 12, aging at 30° C. for 4 h, then 1.2 g 2-hydroxy-1-propanetricarboxylic acid was added to adjust the pH to 9 and age for 4 h under 70° C. The above product was then transferred to stainless steel autoclave lined with PTFE and crystallized at 170° C. for 48 h. After crystallization, the crystallized product was cooled, filtered and washed to neutrality, and then placed in an oven at 120° C. overnight to obtain a sodium type molecular sieve.

[0047] The sodium type molecular sieve and the 1 M NH.sub.4Cl solution were ion-exchanged at a mass ratio of 1:20, stirred in a constant temperature water bath at 70° C. for 4 h, then filtered, washed, dried, and calcined at 520° C. for 5 h. That is, a hydrogen type FeCu—ZSM-5 molecular sieve was prepared and recorded as Catalyst A. FIG. 1 and FIG. 2 are the XRD and an N.sub.2 adsorption-desorption isotherm of the FeCu—ZSM-5 molecular sieve, respectively. As can be seen from FIG. 1, the obtained product was a high crystallinity ZSM-5 molecular sieve. It can be seen from FIG. 2 that the obtained sample contains obvious mesopores, wherein the mesoporous pore size is mainly concentrated at 10 nm, the specific surface area is 441 m.sup.2/g, the external specific surface area is 151 m.sup.2/g, and the Fe.sub.2O.sub.3 content is 3.1% of the total weight of the molecular sieve, wherein the Fe content in the skeleton accounts for 96% of the total iron content. The CuO content is 1.8% of the total weight of the molecular sieve, wherein Cu.sup.2+ accounts for 91% of the total copper content.

Embodiment 2

[0048] This embodiment provides a FeCu—ZSM-5 catalyst, and the preparation steps are the same as those in the Embodiment 1, and only some parameters are modulated, as follows:

[0049] Molecular sieve preparation: 2.18 g Fe(NO.sub.3).sub.3.9H.sub.2O, 0.13 g Cu(NO).sub.2.3H.sub.2O, 10 g H.sub.2O, 5.20 g CTAB, 1.069 g sodium aluminate, 14.18 g water glass (27.6 wt % SiO.sub.2), 2.2 g sulfuric acid were mixed in the beaker. Then adjust the pH to 11, aging at 40° C. for 2 h, then 1.2 g sodium aluminate was added to adjust the pH to 8 and age for 4 h under 80° C. The above product was then transferred to stainless steel autoclave lined with PTFE and crystallized at 160° C. for 24 h. After crystallization, the crystallized product was cooled, filtered and washed to neutrality, and then placed in an oven at 120° C. overnight to obtain a sodium type molecular sieve.

[0050] The sodium type molecular sieve and the 1 M NH.sub.4Cl solution were ion-exchanged at a mass ratio of 1:20, stirred in a constant temperature water bath at 70° C. for 4 h, then filtered, washed, dried, and calcined at 530° C. for 5 h. That is, a hydrogen type FeCu—ZSM-5 molecular sieve was prepared and recorded as Catalyst B. The mesoporous pore size of product is mainly concentrated at 15 nm, the specific surface area is 470 m.sup.2/g, the external specific surface area is 160 m.sup.2/g, and the Fe.sub.2O.sub.3 content is 5.4% of the total weight of the molecular sieve, wherein the Fe content in the skeleton accounts for 95.5% of the total iron content. The CuO content is 0.7% of the total weight of the molecular sieve, wherein Cu.sup.2+ accounts for 90% of the total copper content.

Embodiment 3

[0051] This embodiment provides a FeCu—ZSM-5 catalyst, and the preparation steps are the same as those in the Embodiment 1, and only some parameters are modulated, as follows:

[0052] Molecular sieve preparation: 5.2 g Fe(NO.sub.3).sub.3.9H.sub.2O, 0.11 g Cu(NO.sub.3).sub.2.3H.sub.2O, 18.3 g H.sub.2O, 8.67 g TPABr, 12.27 g aluminum sulfate, 14.18 g water glass (27.6 wt % SiO.sub.2), 2.2 g sulfuric acid were mixed in the beaker. Then adjust the pH to 13, aging at 50° C. for 5 h, then 3.2 g sodium aluminate was added to adjust the pH to 7 and age for 6 h under 60° C. The above product was then transferred to stainless steel autoclave lined with PTFE and crystallized at 170° C. for 48 h. After crystallization, the crystallized product was cooled, filtered and washed to neutrality, and then placed in an oven at 90° C. overnight to obtain a sodium type molecular sieve.

[0053] The sodium type molecular sieve and the 1 M NH.sub.4Cl solution were ion-exchanged at a mass ratio of 1:15, stirred in a constant temperature water bath at 70° C. for 3 h, then filtered, washed, dried, and calcined at 550 T for 7 h. That is, a hydrogen type FeCu—ZSM-5 molecular sieve was prepared and recorded as Catalyst C. The mesoporous pore size of product is mainly concentrated at 30 nm, the specific surface area is 550 m.sup.2/g, the external specific surface area is 300 m.sup.2/g, and the Fe.sub.2O.sub.3 content is 9.4% of the total weight of the molecular sieve, wherein the Fe content in the skeleton accounts for 97% of the total iron content. The CuO content is 0.6% of the total weight of the molecular sieve, wherein Cu.sup.2+ accounts for 90% of the total copper content.

Embodiment 4

[0054] This embodiment provides a FeCu—ZSM-5 catalyst, and the preparation steps are the same as those in the Embodiment 1, and only some parameters are modulated, as follows:

[0055] Activation of minerals: Commercially available diatomaceous earth was dried, pulverized into powder, and 50.00 g of diatomaceous earth powder was calcined at 800° C. for 4 h. Then, 60.00 g of soil, 6 g of sodium hydroxide, and 300 g of water were mechanically stirred at room temperature for 1 h, then activated in an oven at 255° C. for 12 h, and then pulverized for use.

[0056] Molecular sieve preparation: 0.79 g of sodium hydroxide, mixed with 52.2 g of deionized water, then added 0.30 g of Cu(NO.sub.3).sub.2H.sub.2O, 4.7 g of thermally activated diatomite, 0.24 g of activated retentive soil, 0.52 g of n-butylamine. Then, 2 g of hydrochloric acid was added to adjust the pH to 13, transferred to a 60° C. water bath for 30 min, 0.5 g of hydrochloric acid was added to adjust the pH to 12, and the mixture was aged for 4 h in a 70° C. water bath. The above product was then transferred to stainless steel autoclave lined with PTFE and crystallized at 170° C. for 72 h. After crystallization, the crystallized product was cooled, filtered and washed to neutrality, and then placed in an oven at 110° C. overnight to obtain a sodium type molecular sieve.

[0057] The sodium type molecular sieve and the 1 M NH.sub.4Cl solution were ion-exchanged at a mass ratio of 1:30, stirred in a constant temperature water bath at 80° C. for 4 h, then filtered, washed, dried, and calcined at 560° C. for 8 h. That is, a hydrogen type FeCu—ZSM-5 molecular sieve was prepared and recorded as Catalyst D. The mesoporous pore size of product is mainly concentrated at 35 nm, the specific surface area is 470 m.sup.2/g, the external specific surface area is 215 m.sup.2/g, and the Fe.sub.2O.sub.3 content is 1% of the total weight of the molecular sieve, wherein the Fe content in the skeleton accounts for 98% of the total iron content. The CuO content is 0.87% of the total weight of the molecular sieve, wherein Cu.sup.2+ accounts for 93% of the total copper content.

Embodiment 5

[0058] In this embodiment, the catalyst prepared in Embodiment 1 is used for the fixed bed reaction test activity, and includes the following steps: After the catalyst A obtained in Example 1 was tableted and sieved, catalyst particles of 20 to 40 mesh were taken for activity evaluation. The activity evaluation device for the catalyst is a normal pressure type micro fixed bed reaction device, which is composed of a gas mixing preheating furnace and a reaction furnace, and the reactor is a quartz tube having an inner diameter of 7 mm. During the experiment, the reaction was carried out by means of temperature-programming, and the temperature of the heating furnace was controlled by a temperature controller. When the data collection point is reached, stay for 30 minutes for data processing and record data. Reaction conditions: 500 ppm NO, 500 ppm NH.sub.3, 5 v % O.sub.2, N.sub.2 is the equilibrium gas, the total gas flow rate is 600 mL/min, the catalyst dosage is 200 mg, and the reaction volume space velocity is 180,000 h.sup.−1. The concentrations of NO, NH.sub.3 and NO.sub.2 were qualitatively and quantitatively analyzed by a flue gas analyzer (testo340, Germany). The concentration of N.sub.2O was measured by a Fourier transform infrared spectrometer (Nicolet iS50) equipped with a 2 m optical path gas cell.

Embodiment 6

[0059] In this embodiment, the catalyst was used for the fixed bed reaction test activity, and the procedure was the same as in Embodiment 5. The parameters differed in that the catalyst was replaced by Catalyst B prepared in Embodiment 2.

Embodiment 7

[0060] In this embodiment, the catalyst was used for the fixed bed reaction test activity, and the procedure was the same as in Embodiment 5. The parameters differed in that the catalyst was replaced by Catalyst C prepared in Embodiment 3.

Embodiment 8

[0061] In this embodiment, the catalyst was used for the fixed bed reaction test activity, and the procedure was the same as in Embodiment 5. The parameters differed in that the catalyst was replaced by Catalyst D prepared in Embodiment 4.

Embodiment 9

[0062] In this embodiment, the catalyst was used for the fixed bed reaction test activity, and the procedure was the same as in Embodiment 5. The difference in parameters is that the catalyst is Catalyst E which is obtained by hydrothermal treatment of Catalyst D at 700° C. for 4 h.

Contrast Embodiment 1

[0063] (1) In order to demonstrate the technical effects of the present invention, the present invention also provides a comparative example, and the molecular sieve used in the present comparative example is a commercial HZSM-5 purchased by Nankai Catalyst Factory.

[0064] (2) 0.62 g Cu(NO.sub.3).sub.2.3H.sub.2O, 3.22 g of Fe(NO.sub.3).sub.3.9H.sub.2O, and 5 g of deionized water were uniformly mixed, and then slowly added dropwise to 10 g of the molecular sieve in the step (1). Then, it was sonicated for 2 h, air-dried at room temperature, placed in an oven at 120° C. for 8 h, finally calcined at 520° C. for 5 h in a muffle furnace, cooled to room temperature and recorded as catalyst F.

[0065] After the catalyst F was tableted and sieved, catalyst particles of 20 to 40 mesh were taken for activity evaluation. The activity evaluation device for the catalyst is a normal pressure type micro fixed bed reaction device, which is composed of a gas mixing preheating furnace and a reaction furnace, and the reactor is a quartz tube having an inner diameter of 7 mm. During the experiment, the reaction was carried out by means of temperature-programming, and the temperature of the heating furnace was controlled by a temperature controller. When the data collection point is reached, stay for 30 minutes for data processing and record data. Reaction conditions: 500 ppm NO, 500 ppm NH.sub.3, 5 v % O.sub.2, N.sub.2 is the equilibrium gas, the total gas flow rate is 600 mL/min, the catalyst dosage is 200 mg, and the reaction volume space velocity is 180,000 h.sup.−1. The concentrations of NO, NH.sub.3 and NO.sub.2 were qualitatively and quantitatively analyzed by a flue gas analyzer (testo340, Germany). The concentration of N.sub.2O was measured by a Fourier transform infrared spectrometer (Nicolet iS50) equipped with a 2 m optical path gas cell.

Contrast Embodiment 2

[0066] In order to demonstrate the technical effects of the present invention, the present invention also provides a comparative example, and the molecular sieve used in the present comparative embodiment is Catalyst G which is obtained by hydrothermal treatment of the commercial HZSM-5 at 700° C. for 4 h.

[0067] After the catalyst G was tableted and sieved, catalyst particles of 20 to 40 mesh were taken for activity evaluation. The activity evaluation device for the catalyst is a normal pressure type micro fixed bed reaction device, which is composed of a gas mixing preheating furnace and a reaction furnace, and the reactor is a quartz tube having an inner diameter of 7 mm. During the experiment, the reaction was carried out by means of temperature-programming, and the temperature of the heating furnace was controlled by a temperature controller. When the data collection point is reached, stay for 30 minutes for data processing and record data. Reaction conditions: 500 ppm NO, 500 ppm NH.sub.3, 5 v % 02, N.sub.2 is the equilibrium gas, the total gas flow rate is 600 mL/min, the catalyst dosage is 200 mg, and the reaction volume space velocity is 180,000 h.sup.−1. The concentrations of NO, NH.sub.3 and NO.sub.2 were qualitatively and quantitatively analyzed by a flue gas analyzer (testo340, Germany). The concentration of N.sub.2O was measured by a Fourier transform infrared spectrometer (Nicolet iS50) equipped with a 2 m optical path gas cell.

TABLE-US-00001 TABLE 1 Measurement results of various examples and fixed bed reaction test activities Temperature window N.sub.2 selectivity (° C.) (%) Embodiment 5 200-700 >99.0 Embodiment 6 175-700 >99.0 Embodiment 7 180-700 >99.5 Embodiment 8 150-700 >99.5 Embodiment 9 210-700 >99.0 Contrast Embodiment 1 400-500 <90.0 Contrast Embodiment 2 450-500 <85.0 Note: The temperature window is the corresponding temperature range when the conversion rate of NO is >90%.

[0068] As can be seen from Table 1, the mesoporous FeCu—ZSM-5 provided by the present invention has an ultra-wide temperature window (especially low temperature activity), excellent N2 selectivity and good hydrothermal stability. The method of the invention not only has the advantages of low cost, simple process, simple operation, but also good economic and environmental benefits.

[0069] While the invention has been described hereinabove, the invention is not limited to the specific embodiments described herein. Many modifications may be made by those skilled in the art without departing from the spirit and scope of the invention.