Preparation method and application of Ti-MCM-41 mesoporous molecular sieve material

Abstract

The invention relates to a Ti-MCM-41 mesoporous molecular sieve material preparation method and application, the Ti-MCM-41 mesoporous molecular sieve material preparation method comprises the following preparation steps: S1, adding absolute ethyl alcohol into a template agent solution, slowly dropwise adding a titanium source and a silicon source, and reacting to obtain a mixed solution; s2, adjusting the mixed solution obtained in the step S1 to be acidic, and standing at 0 DEG C to obtain a Ti-MCM-41 mesoporous molecular sieve precursor; and S3, roasting the Ti-MCM-41 mesoporous molecular sieve precursor obtained in the step S2 to obtain the Ti-MCM-41 mesoporous molecular sieve. Compared with the prior art, the Ti-MCM-41 mesoporous molecular sieve material is prepared under the acidic and 0 DEG C conditions for the first time. The energy consumption is greatly reduced, more importantly, the operation method is simplified, the equipment requirement is reduced, and a better technical effect is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of mesoporous molecular sieve materials, and in particular to a preparation method and application of a Ti-MCM-41 mesoporous molecular sieve material. Background Art

[0002] Adsorbents are widely used in many fields such as industry, environmental protection and chemical industry. However, its disadvantages are that it is easy to cause secondary pollution and that its adsorption capacity is limited, making it difficult to achieve sufficient removal. Molecular sieve is a new type of adsorption material. Due to its excellent adsorption performance and selectivity, it has been widely used in many adsorption and separation fields. Mesoporous molecular sieves have been a hot research direction in the material science community in recent years. They have been widely used and studied in many aspects such as water treatment. Compared with zeolite molecular sieves, mesoporous molecular sieves have wide pores, uniform pore size distribution, and large specific surface area, which are more conducive to catalytic reactions involving large-volume molecules. In 1992, Mobil Corporation synthesized the silicon-based MCM-41 mesoporous molecular sieve for the first time. The pores are orderly distributed in a hexagonal symmetric manner, which makes the molecular sieve have excellent characteristics such as extremely high specific surface area and significant adsorption capacity. It is a well-developed mesoporous material. However, since silica is its main component, it has great limitations in treating organic pollutants. In 1994, Corma et al. successfully synthesized and prepared Ti-MCM-41 molecular sieve material for the first time using the hydrothermal method. After a series of experiments verified its good catalytic performance in the epoxidation reaction of olefins, its preparation technology has attracted much attention.

[0003] At present, the most common and relatively mature synthesis method for preparing Ti-MCM-41 mesoporous molecular sieve is hydrothermal synthesis, but the biggest disadvantage of hydrothermal synthesis is that the crystallization time is long, the operation is relatively cumbersome, and the equipment requirements are high. Compared with the traditional hydrothermal synthesis method, microwave synthesis can form a large number of crystal nuclei at the same time, significantly shortening the crystallization time and obtaining uniform and fine grains, but its disadvantage is that it has certain requirements for the reaction equipment. Summary of the invention

[0004] The purpose of the present invention is to provide a preparation method and application of Ti-MCM-41 mesoporous molecular sieve material in order to overcome the defects of hydrothermal synthesis method and microwave synthesis method such as complex operation and high equipment requirements.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] One of the technical solutions of the present invention is to provide a method for preparing a Ti-MCM-41 mesoporous molecular sieve material, comprising the following steps:

[0007] S1. Add anhydrous ethanol to the template solution, slowly drop a titanium source and a silicon source into the solution, and react to obtain a mixed solution;

[0008] S2, adjusting the mixed solution obtained in step S1 to acidic, and standing at 0° C. to obtain a Ti-MCM-41 mesoporous molecular sieve precursor;

[0009] S3, calcining the Ti-MCM-41 mesoporous molecular sieve precursor obtained in step S2 to obtain Ti-MCM-41 mesoporous molecular sieve.

[0010] In some specific embodiments, in step S1, the template solution is hexadecyltrimethylammonium bromide solution, the titanium source is tetrabutyl titanate, and the silicon source is tetraethyl silicate.

[0011] In some specific embodiments, in step S1, the reaction temperature is room temperature and the reaction time is 1 to 2 hours.

[0012] In some specific embodiments, in step S2, the mixed solution is adjusted to be acidic by adding an acid solution to the mixed solution, and the acid solution is selected from any one of concentrated sulfuric acid and concentrated hydrochloric acid.

[0013] In some specific embodiments, in step S2, the standing time is 12 to 24 hours.

[0014] In some specific embodiments, in steps S1 and S2, the molar ratio of silicon source: titanium source: template: acid: ethanol: solution is 0.04:(0.0004-0.008):(0.0045-0.0055):(0.145-0.155):(0-2.4):5, wherein the solution is deionized water.

[0015] In some specific embodiments, in steps S1 and S2, the molar ratio of tetraethyl silicate:tetraethyl titanate:hexadecyltrimethylammonium bromide, acid, ethanol, and water is 0.04:(0.0004-0.008):(0.0045-0.0055):(0.145-0.155):(0-2.4):5.

[0016] In some specific embodiments, in step S3, the calcination temperature is 400-700°C, and the calcination time is 4-6 hours. Preferably, the calcination temperature is 500-600°C.

[0017] In some specific embodiments, in step S3, before calcination, the Ti-MCM-41 mesoporous molecular sieve precursor is washed to neutrality.

[0018] The second technical solution of the present invention is to provide an application of Ti-MCM-41 mesoporous molecular sieve prepared by the preparation method described in one of the above technical solutions in adsorbing dye wastewater.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] (1) The present invention is the first to prepare a solution in molar ratio under acidic conditions at 0°C using hexadecyltrimethylammonium bromide as a template, tetrabutyl titanate as a titanium source, and ethyl orthosilicate as a silicon source, and obtain a Ti-MCM-41 mesoporous molecular sieve material through aging, filtering, washing, drying, and calcining.

[0021] (2) The present invention does not use a reaction kettle or a microwave oven, and the Ti-MCM-41 mesoporous molecular sieve can be directly synthesized in an ice-water bath, which not only greatly reduces energy consumption, but more importantly simplifies the operation method, reduces equipment requirements, and achieves better technical effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the XRD diagram of Ti-MCM-41 mesoporous molecular sieve material with Si / Ti=50.

[0023] Figure 2 This is the BET diagram of Ti-MCM-41 mesoporous molecular sieve material with Si / Ti=50.

[0024] Figure 3 This is the adsorption effect diagram of Ti-MCM-41 mesoporous molecular sieve materials with different Si / Ti. DETAILED DESCRIPTION

[0025] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0026] In the following examples and comparative examples, unless otherwise specified, raw materials or processing techniques are conventional commercially available raw materials or conventional processing techniques in the art.

[0027] Embodiment 1:

[0028] This embodiment provides a method for preparing a Ti-MCM-41 mesoporous molecular sieve material with Si / Ti=50, and the steps are as follows:

[0029] (1) Weigh 1.9 g of hexadecyltrimethylammonium bromide and add it to 60 g of deionized water. Stir at 30-50° C. for 3 min to obtain solution A.

[0030] (2) After adding 10 g of anhydrous ethanol to solution A, 0.272 g of tetrabutyl titanate and 8.32 g of tetraethyl silicate were slowly added dropwise and stirred for 1 h to obtain solution B.

[0031] (3) Then, an acid solution (14.86 g of concentrated sulfuric acid dissolved in 30 g of water) was added dropwise to solution B. After the addition was completed, stirring was continued for 30 seconds. The resulting mixture was placed in a 0° C. ice water bath and allowed to stand for 24 hours to obtain a Ti-MCM-41 mesoporous molecular sieve precursor.

[0032] (4) The obtained Ti-MCM-41 mesoporous molecular sieve precursor solid product was filtered, washed with deionized water until neutral, dried at 100°C, and calcined in a muffle furnace at 550°C for 5h to obtain a Ti-MCM-41 mesoporous molecular sieve material with Si / Ti=50.

[0033] Embodiment 2:

[0034] This embodiment provides a method for preparing a Ti-MCM-41 mesoporous molecular sieve material with Si / Ti=30, and the steps are as follows:

[0035] (1) Weigh 1.9 g of hexadecyltrimethylammonium bromide and add it to 60 g of deionized water. Stir at 30-50° C. for 3 min to obtain solution A.

[0036] (2) After adding 10 g of anhydrous ethanol to solution A, 0.454 g of tetrabutyl titanate and 8.32 g of tetraethyl silicate were slowly added dropwise and stirred for 1 h to obtain solution B.

[0037] (3) Then, an acid solution (14.86 g of concentrated sulfuric acid dissolved in 30 g of water) was added dropwise to solution B. After the addition was completed, stirring was continued for 30 seconds. The resulting mixture was placed in a 0° C. ice water bath and allowed to stand for 24 hours to obtain a Ti-MCM-41 mesoporous molecular sieve precursor.

[0038] (4) The obtained Ti-MCM-41 mesoporous molecular sieve precursor solid product was filtered, washed with deionized water until neutral, dried at 100°C, and then calcined at 550°C in a muffle furnace for 5h to obtain a Ti-MCM-41 mesoporous molecular sieve material with Si / Ti=30.

[0039] Embodiment 3:

[0040] This embodiment provides a method for preparing a Ti-MCM-41 mesoporous molecular sieve material with Si / Ti=40, and the steps are as follows:

[0041] (1) Weigh 1.9 g of hexadecyltrimethylammonium bromide and add it to 60 g of deionized water. Stir at 30-50° C. for 3 min to obtain solution A.

[0042] (2) After adding 10 g of anhydrous ethanol to solution A, 0.340 g of tetrabutyl titanate and 8.32 g of tetraethyl silicate were slowly added dropwise and the stirring was continued for 1 h to obtain solution B.

[0043] (3) Then, an acid solution (14.86 g of concentrated sulfuric acid dissolved in 30 g of water) was added dropwise to solution B. After the addition was completed, stirring was continued for 30 seconds. The resulting mixture was placed in a 0° C. ice water bath and allowed to stand for 24 hours to obtain a Ti-MCM-41 mesoporous molecular sieve precursor.

[0044] (4) The obtained Ti-MCM-41 mesoporous molecular sieve precursor solid product was filtered, washed with deionized water until neutral, dried at 100° C., and then calcined at 550° C. in a muffle furnace for 5 h to obtain a Ti-MCM-41 mesoporous molecular sieve material with Si / Ti=40.

[0045] Embodiment 4:

[0046] This embodiment provides a method for preparing a Ti-MCM-41 mesoporous molecular sieve material with Si / Ti=60, and the steps are as follows:

[0047] (1) Weigh 1.9 g of hexadecyltrimethylammonium bromide and add it to 60 g of deionized water. Stir at 30-50° C. for 3 min to obtain solution A.

[0048] (2) After adding 10 g of anhydrous ethanol to solution A, 0.227 g of tetrabutyl titanate and 8.32 g of tetraethyl silicate were slowly added dropwise and the mixture was stirred for 1 h to obtain solution B.

[0049] (3) Then, an acid solution (14.86 g of concentrated sulfuric acid dissolved in 30 g of water) was added dropwise to solution B. After the addition was completed, stirring was continued for 30 seconds. The resulting mixture was placed in a 0° C. ice water bath and allowed to stand for 24 hours to obtain a Ti-MCM-41 mesoporous molecular sieve precursor.

[0050] (4) The obtained Ti-MCM-41 mesoporous molecular sieve precursor solid product was filtered, washed with deionized water until neutral, dried at 100°C, and then calcined at 550°C in a muffle furnace for 5h to obtain a Ti-MCM-41 mesoporous molecular sieve material with Si / Ti=60.

[0051] like Figure 1 As shown, the XRD pattern of Ti-MCM-41 mesoporous molecular sieve material with Si / Ti=50.

[0052] like Figure 2 As shown, the BET diagram of Ti-MCM-41 mesoporous molecular sieve material with Si / Ti=50.

[0053] like Figure 3 As shown, the effect diagram of the adsorption of methylene blue by Ti-MCM-41 mesoporous molecular sieve materials with different Si / Ti over time. It can be seen from the figure that the adsorption rate of methylene blue solution by Ti-MCM-41 mesoporous molecular sieve material with Si / Ti=50 is as high as 94%.

[0054] Comparative Example 1:

[0055] Ti-MCM-41 mesoporous molecular sieve material was prepared by equal volume impregnation method. First, MCM-41 molecular sieve was prepared by ice-water bath method and TiO2 sol was prepared by sol-gel method. Then the mixture (Si / Ti=50) was stirred and placed in ultrasonic disperser. After calcination, Ti-MCM-41 molecular sieve was obtained. The adsorption rate of methylene blue by the prepared material was 84%.

[0056] The method for preparing MCM-41 molecular sieve by ice-water bath method is the same as the preparation method in Example 1, except that tetrabutyl titanate is omitted.

[0057] The method for preparing TiO2 sol by sol-gel method is as follows: 0.272g of tetrabutyl titanate is slowly added dropwise to 15mL of anhydrous ethanol under stirring conditions, and stirring is continued for 30min after the addition is completed to obtain a light yellow liquid, which is recorded as solution A. 1mL of glacial acetic acid and 5mL of deionized water are slowly added to 15mL of anhydrous ethanol, and an appropriate amount of concentrated nitric acid is added to ensure that the pH of the solution is less than 3, and stirring is continued for 30min to obtain a white turbid liquid, which is recorded as solution B. Solution B is slowly added dropwise to solution A under stirring conditions, and stirring is continued for 1h to obtain TiO2 sol.

[0058] The present invention prepares Ti-MCM-41 mesoporous molecular sieve by only adding tetrabutyl titanate and tetraethyl silicate successively, stirring and placing in ice water, and the adsorption rate of the prepared material to methylene blue solution is as high as 94%. Compared with comparative example 1, the present invention has simple preparation steps, simple requirements for reaction instruments and equipment, and greatly improves the adsorption rate to methylene blue solution.

[0059] Comparative Example 2:

[0060] Compared with Example 1, most of the steps are the same, except that no acid solution is added during the preparation process.

[0061] Compared with the Ti-MCM-41 mesoporous molecular sieve material of the present application, the adsorption rate of the methylene blue solution of the prepared material is 90.7%, while the adsorption rate of the methylene blue solution of the present application is 94%.

[0062] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A method for preparing a Ti-MCM-41 mesoporous molecular sieve material, characterized in that: The steps include: S1. Add anhydrous ethanol to the template solution, slowly drop a titanium source and a silicon source into the solution, and react to obtain a mixed solution; S2, adjusting the mixed solution obtained in step S1 to acidic, and standing at 0° C. to obtain a Ti-MCM-41 mesoporous molecular sieve precursor; S3, calcining the Ti-MCM-41 mesoporous molecular sieve precursor obtained in step S2 to obtain Ti-MCM-41 mesoporous molecular sieve.

2. The preparation method according to claim 1, characterized in that: In step S1, the template solution is hexadecyltrimethylammonium bromide solution, the titanium source is tetrabutyl titanate, and the silicon source is tetraethyl silicate.

3. The preparation method according to claim 1, characterized in that: In step S1, the reaction temperature is room temperature and the reaction time is 1 to 2 hours.

4. The preparation method according to claim 1, characterized in that: In step S2, the mixed solution is adjusted to be acidic by adding an acid solution into the mixed solution, and the acid solution is selected from any one of concentrated sulfuric acid and concentrated hydrochloric acid.

5. The preparation method according to claim 1, characterized in that: In step S2, the standing time is 12 to 24 hours.

6. The preparation method according to claim 1, characterized in that: In steps S1 and S2, the molar ratio of silicon source:titanium source:template:acid:ethanol:solution is 0.04:(0.0004-0.008):(0.0045-0.0055):(0.145-0.155):(0-2.4):

5.

7. The preparation method according to claim 1, characterized in that: In steps S1 and S2, the molar ratio of tetraethyl silicate:tetraethyl titanate:hexadecyltrimethylammonium bromide, acid, ethanol, and water is 0.04:(0.0004-0.008):(0.0045-0.0055):(0.145-0.155):(0-2.4):

5.

8. The preparation method according to claim 1, characterized in that: In step S3, the calcination temperature is 400-700° C. and the calcination time is 4-6 hours.

9. The preparation method according to claim 1, characterized in that: In step S3, before calcination, the Ti-MCM-41 mesoporous molecular sieve precursor is washed to neutrality.

10. Application of Ti-MCM-41 mesoporous molecular sieve in adsorption of dye wastewater, characterized in that: The Ti-MCM-41 mesoporous molecular sieve is obtained based on the preparation method described in any one of claims 1 to 9.

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