阅读说明：本技术 一种沸石分子筛的制备方法及其应用 (Preparation method and application of zeolite molecular sieve ) 是由 王军 周瑜 王远 刘晓玲 张建林 于 2020-06-04 设计创作，主要内容包括：本发明提出了一种沸石分子筛的制备方法及其应用,涉及一种沸石吸附剂的制备方法和应用,具体涉及制备杂原子Fe取代的FM丝光沸石单块材料的制备方法及其应用,所述沸石分子筛由Fe与SiO<Sub>2</Sub>组成,所述Fe与SiO<Sub>2</Sub>的比以摩尔比计：Fe/SiO<Sub>2</Sub>＝0.1％-2％。本发明提供了一种高效的、低成本的、节能且环保的合成路线,制备杂原子Fe取代的FM丝光沸石单块材料,用于CO<Sub>2</Sub>捕获,取得了显著成效,吸附剂易于重复使用,绿色环保。(The invention provides a preparation method and application of a zeolite molecular sieve, relates to a preparation method and application of a zeolite adsorbent, and particularly relates to a preparation method and application of a heteroatom Fe-substituted FM mordenite monolithic material 2 Composition of said Fe and SiO 2 In terms of mole ratios: Fe/SiO 2 0.1% -2%. The invention provides an efficient, low-cost, energy-saving and environment-friendly synthetic route for preparationHeteroatom Fe substituted FM mordenite monolithic material for CO 2 The capture has achieved remarkable results, the adsorbent is easy to reuse, green and environment-friendly.)

1. A method for preparing a zeolitic molecular sieve comprising the steps of:

(1) mixing a silicon source, an iron source and water, wherein the molar ratio of the reaction mixture is Fe/SiO₂0.1% -2%, H₂O/SiO₂30-40, adding acid liquor to adjust the pH value to 0.4-3;

(2) adding an aluminum source into the mixed solution, wherein the aluminum source comprises the following components in molar ratio: SiO 2₂/Al₂O₃Is 10 to 30, and alkali liquor is added to adjust the pH value to 9 to 13;

(3) adding the mixed solution into a high-pressure reaction kettle, statically crystallizing for 10-18 days at the temperature of 160-200 ℃, washing and drying to prepare the zeolite molecular sieve;

the silicon source is one of silica sol, tetramethyl orthosilicate, tetraethyl orthosilicate, tetramethyl silicic acid, silicic acid or silicon oxide, the iron source is one of ferric nitrate, ferric chloride and ferric sulfate, the acid solution is one of sulfuric acid, hydrochloric acid and nitric acid or perchloric acid, the aluminum source is one of sodium metaaluminate, aluminum sulfate and aluminum chloride, and the alkali liquor is sodium hydroxide solution.

2. The method of claim 1, wherein the step ofIn the step (1), the reaction mixture comprises the following components in molar ratio: Fe/SiO₂Is 0.5%.

3. The method according to claim 1, wherein the pH is adjusted to 0.8 in the step (1).

4. The method according to claim 1, wherein the pH is adjusted to 11 in the step (2).

5. The method according to claim 1, wherein the autoclave in the step (3) is a stainless steel autoclave lined with polytetrafluoroethylene.

6. The method according to claim 1, wherein the autoclave temperature in the step (3) is 180 ℃.

7. The method according to claim 1, wherein the crystallization in the step (3) is carried out for 14 days.

8. The method according to claim 5, wherein the autoclave has a volume of 50L.

9. Use of a zeolitic molecular sieve according to any of claims 1 to 8 for the separation of carbon dioxide in nitrogen or methane gas.

Technical Field

The technology relates to a preparation method and application of a zeolite adsorbent, in particular to a preparation method and application of a heteroatom Fe substituted FM mordenite monolithic material.

Background

Adsorption and separation have very important application values in industry, and thus research on them is gradually receiving wide attention from scientists. In recent years, the emission of greenhouse gases is rising year by year, the emission reduction pressure is increasing day by day, and based on the background, CO₂Adsorption and separation in the mixed gas become very urgent. In natural gas purification (CO)₂、CH₄Mixed gas), pre-power plant Combustion (CO)₂、H₂Mixed gas) and post Combustion (CO)₂、N₂Mixed gas) technical aspect, CO₂Have an irreplaceable position. The development process in this field has shown for many years that porous solid adsorbents are in CO₂The method has excellent application prospect in the field of capture and separation, and the adsorbent comprises alkylamine functionalized mesoporous silica, carbon materials, metal organic frameworks, polymers, zeolite and the like. However in CO₂The following challenges are also faced in adsorptive separation systems of (1): (1) the preparation cost of the material is high, and the manufacturing difficulty is high; (2) material pair CO₂Limited gas capture capacity and selectivity; (3) the reproducibility and stability of the material are general.

Generally, an ideal target adsorbent should have a high CO at the same time₂Adsorption capacity, excellent selectivity, and strong chemical and mechanical stability. The manufacturing cost of materials is also a significant concern in large-scale industrial applications. In the preparation of zeolite molecular sieve, the iron state of iron loaded by the traditional impregnation method is difficult to control, and the iron is difficult to enter the framework and cannot exist stably.

Disclosure of Invention

The invention provides a molecular sieve which has good effect of adsorbing carbon dioxide and is used for separating carbon dioxide and other gases.

A method for preparing a zeolitic molecular sieve comprising the steps of:

(1) mixing a silicon source, an iron source and water, wherein the molar ratio of the reaction mixture is Fe/SiO₂0.1% -2%, H₂O/SiO₂30-40, adding acid liquor to adjust the pH value to 0.4-3;

(2) adding an aluminum source into the mixed solution, wherein the aluminum source comprises the following components in molar ratio: SiO 2₂/Al₂O₃Is 10 to 30, and alkali liquor is added to adjust the pH value to 9 to 13;

(3) adding the mixed solution into a high-pressure reaction kettle, statically crystallizing for 10-18 days at the temperature of 160-200 ℃, washing and drying to prepare the zeolite molecular sieve;

the silicon source is one of silica sol, tetramethyl orthosilicate, tetraethyl orthosilicate, tetramethyl silicic acid, silicic acid or silicon oxide, the iron source is one of ferric nitrate, ferric chloride and ferric sulfate, the acid solution is one of sulfuric acid, hydrochloric acid and nitric acid or perchloric acid, the aluminum source is one of sodium metaaluminate, aluminum sulfate and aluminum chloride, and the alkali liquor is sodium hydroxide solution.

Preferably, the reaction mixture in step (1) is prepared by mixing the following components in a molar ratio: Fe/SiO₂Is 0.5%.

Preferably, the pH is adjusted to 0.8 in step (1).

Preferably, the pH is adjusted to 11 in step (2).

Preferably, the high-pressure reaction kettle in the step (3) is a stainless steel high-pressure reaction kettle lined with polytetrafluoroethylene, and the capacity of the high-pressure reaction kettle is 50L.

Preferably, the temperature of the high-pressure reaction kettle in the step (3) is 180 ℃.

Preferably, the crystallization in the step (3) is carried out for 14 days.

The preferred volume of the autoclave is 50L.

Use of a zeolite molecular sieve for separating carbon dioxide to neutralize nitrogen or methane.

Advantageous effects

(1) The invention introduces iron into a zeolite molecular sieve by a one-step hydrothermal method, and the iron in the target material exists in two forms: the ferrite-silicon bond exists in the framework; the iron oxide clusters exist in the pore channels, and the existence form of iron in the adsorption system is the key point for separating gas. The iron-containing zeolite molecular sieve (FM) synthesized by the invention is used for multi-component adsorption and desorption separation of a fixed bed layer, and can still keep good separation effect after multiple rounds of tests.

(2) The invention provides an efficient, low-cost, energy-saving and environment-friendly synthetic route for preparing heteroatom-substituted FM zeolite monolithic material for CO₂The capture has achieved remarkable results, the adsorbent is easy to reuse, green and environment-friendly.

Drawings

Fig. 1 is an XRD pattern of FM-n series samples and M-1 (n-2, 3, 4);

FIG. 2 is an SEM image of an FM-3 sample;

FIG. 3 is an EXAFS plot of the FM-3 sample;

FIG. 4 is a graph of adsorption isotherm of M-1 at an adsorption temperature of 273K;

FIG. 5 is a graph of adsorption isotherm of M-1 at an adsorption temperature of 298K;

FIG. 6 is an adsorption isotherm plot of FM-3 at an adsorption temperature of 273K;

FIG. 7 is an adsorption isotherm plot of FM-3 at an adsorption temperature of 298K;

FIG. 8 shows that M-1 adsorbs CO at a temperature of 273K₂/N₂、CO₂/CH₄Adsorption equilibrium diagram;

FIG. 9 shows that M-1 adsorbs CO at an adsorption temperature of 298K₂/N₂、CO₂/CH₄Adsorption equilibrium diagram;

FIG. 10 shows FM-3 at an adsorption temperature of 273K CO₂/N₂、CO₂/CH₄Adsorption equilibrium diagram;

FIG. 11 shows FM-3 at an adsorption temperature of 298K CO₂/N₂、CO₂/CH₄Adsorption equilibrium diagram.

Detailed Description