A method for preparing a multi-component Y-type molecular sieve with high CO2 adsorption performance

Abstract

The present application relates to the technical field of molecular sieve, especially to B01J20 / 00, more particularly to a preparation method of multi-component Y-type molecular sieve with high CO2 adsorption performance. The preparation method of multi-component Y-type molecular sieve comprises the following steps: S1, dissolving and stirring soluble inorganic salt to obtain a precursor solution; S2, ultrasonic treatment is performed on the precursor solution, and then the precursor solution is placed in a reaction kettle for hydrothermal reaction; S3, after the reaction is completed, centrifugation, drying and grinding are performed, and the multi-component Y-type molecular sieve (NaKCaY) is obtained. In the preparation process of the multi-component Y-type molecular sieve, the Si / Al ratio is adjusted, the alkali metal K salt, the alkaline earth metal Ca salt and the modifier are added, the Y-type molecular sieve with high specific surface area, large pore volume and moderate pore size is obtained, the addition of potassium silicate, calcium chloride and the modifier further improves the CO2 adsorption and capture performance while greatly improving the specific surface area. The method has the advantages of mild synthesis conditions, simple steps, high reproducibility and the like.

Description

Technical Field

[0001] This invention relates to the field of molecular sieve technology, particularly to the field of B01J20 / 00, and more specifically to a method for preparing a multi-component Y-type molecular sieve with high CO2 adsorption performance. Background Technology

[0002] Molecular sieves generally refer to aluminosilicate materials with a uniform microporous structure. They can be used for drying, adsorption, catalysis, ion exchange, etc. These materials have small pore sizes, often in the nanometer range, generally close to the size of small molecules, including methane, water, ammonia, and nitric oxide. Molecular sieves can be used to screen molecules according to their molecular weight. Based on their constituent molecular crystal structures, molecular sieves are mainly classified into three types: Type A, Type X, and Type Y. Type A: The main component is aluminosilicate, with a pore size of 4 Å (1 Å = 10⁻⁶ Å). -10 m), called 4A (also known as sodium A type) molecular sieve; using Ca 2+ Exchange Na in 4A molecular sieve + This results in a pore size of 5A, which is known as 5A (also called calcium A type) molecular sieve; using K... + Exchange Na of 4A molecular sieve + This results in a pore size of 3A, known as 3A (also called potassium A type) molecular sieve. X type: Due to different crystal structures of aluminosilicates (different silicon-to-aluminum ratios), molecular sieve crystals with pore sizes of 9-10A are formed, called 13X (also called sodium X type) molecular sieve; using Ca... 2+ Exchange Na in 13X molecular sieve + This process forms molecular sieve crystals with a pore size of 9 Å, known as 10X (also called calcium X type) molecular sieves. Y-type molecular sieves are widely used in industry for preparing catalysts or catalyst supports for various acid-catalyzed reactions such as catalytic cracking, hydrocracking, isomerization, and alkylation, making them the most widely used molecular sieve. The properties and functions of Y-type molecular sieves mainly depend on their silica-alumina framework ratio and corresponding pore structure. A higher silica-alumina ratio often results in stronger thermal stability and increased acid tolerance. Furthermore, their hydrophilicity / hydrophobicity changes with increasing silica-alumina ratio, thus affecting the adsorption performance of the molecular sieve. Molecular sieves with a suitable topological structure have moderate specific surface area and pore size, good stability, and simple preparation methods, making them a research hotspot in the field of carbon dioxide adsorption. However, the adsorption capacity of the raw molecular sieve powder for weakly acidic carbon dioxide is relatively low.

[0003] The existing technology, CN101524638B, discloses a method for preparing submicron molecular sieve carbon dioxide. The preparation steps include: adding a potassium-containing compound as a directing agent and low silica-alumina ratio molecular sieve powder as a seed crystal, then using sodium / calcium salt for ion exchange, adding a binder to form the sieve, and drying and activating it to obtain the final product. This submicron molecular sieve can effectively adsorb water and carbon dioxide at room temperature, but the pore size of the molecular sieve is not specifically disclosed, which is not conducive to precise adsorption. In addition, bentonite, montmorillonite, kaolin, etc. are also required in the molecular sieve as binders, which is also not conducive to the control of the pore size of the molecular sieve. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a method for preparing a multi-component Y-type molecular sieve with high CO2 adsorption performance, comprising at least the following steps:

[0005] S1. Mix and dissolve the soluble inorganic salts and stir to obtain a precursor solution;

[0006] S2. The precursor solution is ultrasonically treated and then placed in a reaction vessel for hydrothermal reaction.

[0007] S3. After the reaction is complete, centrifuge, dry and grind to obtain the final product.

[0008] Preferably, the soluble inorganic salt includes alkali metal inorganic salts, alkaline earth metal inorganic salts, and non-alkali metal inorganic salts.

[0009] More preferably, the alkali metal inorganic salt is an alkali metal silicate.

[0010] More preferably, the alkali metal inorganic salt includes sodium silicate and potassium silicate.

[0011] Preferably, the alkaline earth metal inorganic salt includes calcium-containing inorganic salts.

[0012] More preferably, the calcium-containing inorganic salt includes one or more of calcium chloride, calcium hydrogen sulfate, calcium dihydrogen phosphate, calcium bromide, calcium permanganate, and calcium bicarbonate.

[0013] More preferably, the calcium-containing inorganic salt is calcium chloride.

[0014] Preferably, the non-alkali metal inorganic salt includes aluminum-containing inorganic salts.

[0015] More preferably, the aluminum-containing inorganic salt includes one or more of aluminum chloride, aluminum sulfate, and aluminum nitrate.

[0016] More preferably, the aluminum-containing inorganic salt includes aluminum chloride.

[0017] Preferably, the mass ratio of aluminum chloride, sodium silicate, potassium silicate, and calcium chloride is (5-10):(1-5):(3-7):1.

[0018] More preferably, the mass ratio of aluminum chloride, sodium silicate, potassium silicate, and calcium chloride is (7-8):(3-4):(4-5):1.

[0019] As an implementable example, the aluminum chloride, sodium silicate, potassium silicate, and calcium chloride mentioned include hydrated forms.

[0020] Preferably, the raw materials prepared in step S1 may also include a modifier.

[0021] More preferably, the modifier includes a strong base-weak acid salt or an alcohol.

[0022] As an example of implementation, the strong base-weak acid salt includes sodium citrate; and the alcohol includes isopropanol.

[0023] Preferably, the mass ratio of the soluble inorganic salt to the modifier is 270:(1-26).

[0024] More preferably, the mass ratio of the soluble inorganic salt to the modifier is 270:(3-14).

[0025] Preferably, the hydrothermal reaction in step S2 is carried out at a temperature of 180-200°C for 20-24 hours.

[0026] Preferably, the process after step S3 may also include a roasting step.

[0027] Preferably, the roasting temperature in the roasting step is 300-400℃, and the roasting time is 1-3h.

[0028] Beneficial effects

[0029] (I) In this invention, specific aluminum and silicon sources are selected, and the aluminum, silicon, and calcium sources are mixed and dissolved, utilizing Ca... 2+ Precrystallization can effectively shorten the induced nucleation time of molecular sieves, enabling the molecular sieves to form more tiny silicon-aluminum particles, thereby achieving controllable regulation of specific surface area, pore size, and pore volume.

[0030] (II) The present invention mainly adopts a one-step method for alkali and alkaline earth metal exchange, which can effectively improve the adsorption performance of molecular sieves for carbon dioxide.

[0031] (III) Currently available molecular sieve powders have a low adsorption capacity for weakly acidic carbon dioxide. This invention uses alkali metal modification, which makes the molecular sieve exhibit a stronger affinity and adsorption capacity for carbon dioxide.

[0032] (iv) In addition to soluble inorganic salts, the raw materials prepared in this invention may also include modifiers, which avoids the use of binders, ensures that the Y-type molecular sieve has a topological structure, a moderate specific surface area and pore size, and good stability.

[0033] (v) The preparation process described in this invention is simple, the raw materials are low in cost and widely available, and the finished product can be obtained even without roasting, resulting in excellent practical application effects. Attached Figure Description

[0034] Figure 1 The image shows the X-ray diffraction (XRD) pattern of the multi-component Y-type molecular sieve in Example 1.

[0035] Figure 2 The image shows the X-ray diffraction (XRD) pattern of the multi-component Y-type molecular sieve in Example 2.

[0036] Figure 3 This is a scanning electron microscope (SEM) image of the multi-component Y-type molecular sieve in Example 1.

[0037] Figure 4 This is a scanning electron microscope (SEM) image of the multi-component Y-type molecular sieve in Example 2.

[0038] Figure 5 The carbon dioxide thermogravimetric curve of the multi-component Y-type molecular sieve in Example 1 is shown.

[0039] Figure 6 The carbon dioxide thermogravimetric curve of the multi-component Y-type molecular sieve in Example 2 is shown.

[0040] Figure 7 Thermogravimetric curve of carbon dioxide for the multi-component Y-type molecular sieve in Example 3.

[0041] Figure 8 N2 adsorption-desorption isotherms of the multi-component Y-type molecular sieve in Example 3.

[0042] Figure 9 The image shows the pore size distribution curve of the multi-component Y-type molecular sieve in Example 4.

[0043] Figure 10 This is a scanning electron microscope (SEM) image of the multi-component Y-type molecular sieve in Example 4. Detailed Implementation

[0044] Example 1

[0045] This embodiment provides a method for preparing a multi-component Y-type molecular sieve with high CO2 adsorption performance, specifically comprising the following steps:

[0046] S1. Weigh out 1.2692g of aluminum chloride (AlCl3·H2O, mass fraction 98%), 0.5625g of sodium silicate (Na2SiO3·9H2O, mass fraction 19.3%), and 0.6910g of potassium silicate (K2SiO3·xH2O, mass fraction 47.0%), dissolve them in 40mL of deionized water to obtain the precursor solution;

[0047] S2. The precursor solution was ultrasonically stirred for 15 minutes and then transferred to a hydrothermal reactor for hydrothermal reaction. The hydrothermal reaction temperature was 200℃ and the reaction time was 24 hours.

[0048] S3. After the reaction is complete, centrifuge, dry and grind to obtain the final product.

[0049] The aluminum chloride, sodium silicate, and potassium silicate mentioned are all commercially available products.

[0050] Figure 5 The thermogravimetric curve of carbon dioxide for the multi-component Y-type molecular sieve in Example 1 is shown, exhibiting excellent carbon dioxide adsorption performance. X-ray diffraction of the molecular sieve prepared in this example yielded the following results: Figure 1 As shown, the diffraction peaks indicate a silica phase structure. The molecular sieve prepared in this embodiment was subjected to electron scanning, and the resulting electron micrograph is shown below. Figure 3 As shown, its surface exhibits irregular channels of approximately 5 nm. Its specific surface area is 389 m². 2 / g, with a pore size of 3.587nm and a water adsorption capacity of 25.72%.

[0051] Example 2

[0052] This embodiment provides a method for preparing a multi-component Y-type molecular sieve with high CO2 adsorption performance, specifically comprising the following steps:

[0053] S1. Weigh out 1.2692g of aluminum chloride (AlCl3·H2O, mass fraction 98%), 0.5625g of sodium silicate (Na2SiO3·9H2O, mass fraction 19.3%), 0.6910g of potassium silicate (K2SiO3·xH2O, mass fraction 47.0%), and 0.1679g of calcium chloride (CaCl2·2H2O, mass fraction 99.0%), and dissolve them in 40mL of deionized water to obtain the precursor solution.

[0054] S2. The precursor solution was ultrasonically stirred for 15 minutes and then transferred to a hydrothermal reactor for hydrothermal reaction. The hydrothermal reaction temperature was 200℃ and the reaction time was 24 hours.

[0055] S3. After the reaction is complete, centrifuge, dry and grind, then calcine to obtain the product; the calcine temperature is 400℃, the calcine time is 1h, and the heating rate is 5℃ / min.

[0056] The aluminum chloride, sodium silicate, potassium silicate, and calcium chloride mentioned are all commercially available products.

[0057] Figure 6 The thermogravimetric curve of carbon dioxide for the multi-component Y-type molecular sieve in Example 2 shows good carbon dioxide adsorption performance. X-ray diffraction of the molecular sieve prepared in this example yielded the following results: Figure 2 As shown, the diffraction peaks indicate a silica phase structure. The molecular sieve prepared in this embodiment was subjected to electron scanning, and the resulting electron micrograph is shown below. Figure 4 As shown, its surface exhibits irregular channels of approximately 5 nm. Its specific surface area is 560 m². 2 / g, with a pore size of 4.648nm and a water adsorption capacity of 30.96%.

[0058] Example 3

[0059] This embodiment provides a method for preparing a multi-component Y-type molecular sieve with high CO2 adsorption performance, specifically comprising the following steps:

[0060] S1. Weigh out 1.2692g of aluminum chloride (AlCl3·H2O, mass fraction 98%), 0.5625g of sodium silicate (Na2SiO3·9H2O, mass fraction 19.3%), 0.6910g of potassium silicate (K2SiO3·xH2O, mass fraction 47.0%), 0.1679g of calcium chloride (CaCl2·2H2O, mass fraction 99.0%), and 0.139g of sodium citrate (Na3C6H5O7·2H2O, mass fraction 99.9%), and dissolve them in 40mL of deionized water to obtain the precursor solution.

[0061] S2. The precursor solution is ultrasonically stirred for 15 minutes and then transferred to a hydrothermal reactor for hydrothermal reaction. The hydrothermal reaction temperature is 200℃ and the reaction time is 24 hours.

[0062] S3. After the reaction is complete, centrifuge, dry and grind, then calcine to obtain the product; the calcine temperature is 400℃, the calcine time is 1h, and the heating rate is 5℃ / min.

[0063] The aluminum chloride, sodium silicate, potassium silicate, calcium chloride, and sodium citrate mentioned are all commercially available products.

[0064] Figure 7 The thermogravimetric curve of carbon dioxide for the multi-component Y-type molecular sieve in Example 3 shows good carbon dioxide adsorption performance. Figure 8 The N2 adsorption-desorption isotherm of the multi-component Y-type molecular sieve in Example 3 has a specific surface area of ​​424 m2 / g, a pore size of 4.817 nm, and a water adsorption capacity of 25.72%.

[0065] Example 4

[0066] This embodiment provides a method for preparing a multi-component Y-type molecular sieve with high CO2 adsorption performance, specifically comprising the following steps:

[0067] S1. Weigh out 1.1122 g of aluminum chloride (AlCl3·H2O, mass fraction 98%), 0.4811 g of sodium silicate (Na2SiO3·9H2O, mass fraction 19.3%), 0.6003 g of potassium silicate (K2SiO3·xH2O, mass fraction 47.0%), 0.1679 g of calcium chloride (CaCl2·2H2O, mass fraction 99.0%), and 0.0272 g of isopropanol (C3H8O, mass fraction 99.9%), and dissolve them in 40 mL of deionized water to obtain the precursor solution.

[0068] S2. The precursor solution was ultrasonically stirred for 15 minutes and then transferred to a hydrothermal reactor for hydrothermal reaction. The hydrothermal reaction temperature was 200℃ and the reaction time was 24 hours.

[0069] S3. After the reaction is complete, centrifuge, dry and grind, then calcine to obtain the product; the calcine temperature is 350℃, the calcine time is 3h, and the heating rate is 5℃ / min.

[0070] The aluminum chloride, sodium silicate, potassium silicate, calcium chloride, and isopropanol mentioned are all commercially available products.

[0071] The pore size distribution curve of the multi-component Y-type molecular sieve in Example 4, with a specific surface area of ​​380 m². 2 / g, pore volume is 0.2512cm³ 3 / g nm. Figure 10 The image shows a scanning electron microscope image of the multi-component Y-type molecular sieve in Example 4, which has small pores and an irregular shape.

[0072] Example 5

[0073] This embodiment provides a method for preparing a multi-component Y-type molecular sieve with high CO2 adsorption performance, specifically comprising the following steps:

[0074] S1. Weigh out 1.2692g of aluminum chloride (AlCl3·H2O, mass fraction 98%), 0.5625g of sodium silicate (Na2SiO3·9H2O, mass fraction 19.3%), 0.6910g of potassium silicate (K2SiO3·xH2O, mass fraction 47.0%), 0.1679g of calcium chloride (CaCl2·2H2O, mass fraction 99.0%), and 0.099g of sodium citrate (Na3C6H5O7·2H2O, mass fraction 99.9%), and dissolve them in 40mL of deionized water to obtain the precursor solution.

[0075] S2. The precursor solution was ultrasonically stirred for 15 minutes and then transferred to a hydrothermal reactor for hydrothermal reaction. The hydrothermal reaction temperature was 200℃ and the reaction time was 24 hours.

[0076] S3. After the reaction is complete, centrifuge, dry and grind, then calcine to obtain the product; the calcine temperature is 400℃, the calcine time is 0h, and the heating rate is 5℃ / min.

[0077] The molecular sieve prepared in this embodiment has a specific surface area of ​​283 m². 2 / g, pore volume 0.2434cm³ 3 / g, with a pore size of 14.36nm.

[0078] Example 6

[0079] This embodiment provides a method for preparing a multi-component Y-type molecular sieve with high CO2 adsorption performance, specifically comprising the following steps:

[0080] S1. Weigh out 1.2692g of aluminum chloride (AlCl3·H2O, mass fraction 98%), 0.5625g of sodium silicate (Na2SiO3·9H2O, mass fraction 19.3%), and 0.099g of sodium citrate (Na3C6H5O7·2H2O, mass fraction 99.9%) and dissolve them in 40mL of deionized water to obtain the precursor solution.

[0081] S2. The precursor solution was ultrasonically stirred for 15 minutes and then transferred to a hydrothermal reactor for hydrothermal reaction. The hydrothermal reaction temperature was 200℃ and the reaction time was 24 hours.

[0082] S3. After the reaction is complete, centrifuge, dry and grind, then calcine to obtain the product; the calcine temperature is 400℃, the calcine time is 2h, and the heating rate is 5℃ / min.

[0083] The aluminum chloride, sodium silicate, potassium silicate, calcium chloride, and sodium citrate mentioned are all commercially available products.

[0084] The specific surface area of ​​the molecular sieve obtained in this example is 59.8 m². 2 / g, pore volume 0.0243cm³ 3 / g, pore size is 4.971nm, water adsorption capacity is 5.59%.

[0085] Example 7

[0086] This example provides a method for preparing a multi-component Y-type molecular sieve with high CO2 adsorption performance, specifically through the following steps:

[0087] S1. Weigh 1.2692g of aluminum chloride (AlCl3·H2O, mass fraction 98%) and 0.5625g of sodium silicate (Na2SiO3·9H2O, mass fraction 19.3%) and dissolve them in 40mL of deionized water to obtain the precursor solution.

[0088] S2. The precursor solution was ultrasonically stirred for 15 minutes and then transferred to a hydrothermal reactor for hydrothermal reaction. The hydrothermal reaction temperature was 180℃ and the reaction time was 20 hours.

[0089] S3. After the reaction is complete, centrifuge, dry and grind, then calcine to obtain the product; the calcine temperature is 400℃, the calcine time is 2h, and the heating rate is 5℃ / min.

[0090] The aluminum chloride, sodium silicate, potassium silicate, calcium chloride, and sodium citrate mentioned are all commercially available products.

[0091] In this example, the yield of the molecular sieve was 19.3%, and the specific surface area was 59.8 m². 2 / g, pore volume 0.0243cm³ 3 / g, with a pore size of 4.971nm.

Claims

1. A method for preparing a multi-component Y-type molecular sieve with high CO2 adsorption performance, characterized in that, At least the following steps are included: S1. Mix and dissolve the soluble inorganic salt and the modifier, and stir to obtain a precursor solution; S2. The precursor solution is ultrasonically treated and then placed in a reaction vessel for hydrothermal reaction. S3. After the reaction is complete, centrifuge, dry, grind, and calcine to obtain the final product. The soluble inorganic salts mentioned are aluminum chloride, sodium silicate, potassium silicate, and calcium chloride; The mass ratio of aluminum chloride, sodium silicate, potassium silicate, and calcium chloride is (5-10):(1-5):(3-7):1; The modifiers mentioned include one of sodium citrate and isopropanol; The mass ratio of the soluble inorganic salt to the modifier is 270:(1-26); The roasting temperature in the roasting step is 300-400℃, and the roasting time is 1-3 hours. The hydrothermal reaction in S2 has a reaction temperature of 180-200℃ and a reaction time of 20-24h.

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