Modified A-type molecular sieve, preparation method thereof and method for removing ammonia impurities in hydrogen

Abstract

The invention relates to a modified A-type molecular sieve, a preparation method thereof and a method for removing ammonia impurities in hydrogen. The modified A-type molecular sieve comprises an A-type molecular sieve, a first metal active component and a second metal active component, wherein the first metal active component and the second metal active component are loaded on the A-type molecular sieve; the first metal active component comprises Cu < 2 + >, and the second metal active component comprises Zn < 2 + >; on the basis of the total weight of the modified A-type molecular sieve, the content of the first metal active component is 6.16-34.95 wt%, the content of the second metal active component is 3.02-15.56 wt%, and the first metal active component and the second metal active component are calculated in the form of metal oxides. The modified A-type molecular sieve disclosed by the invention has relatively high ammonia gas adsorption capacity, and can effectively adsorb trace ammonia gas.

Description

A modified type A molecular sieve, its preparation method, and a method for removing ammonia impurities from hydrogen gas. Technical Field

[0001] This application relates to the field of adsorbent technology, specifically to a modified type A molecular sieve, its preparation method, and a method for removing ammonia impurities from hydrogen gas. Background Technology

[0002] Proton exchange membrane fuel cells (PEMFCs) are among the most promising fuel cells due to their high efficiency, fast start-up speed, and low operating temperature. However, even trace amounts of impurity gases can poison the fuel cell and cause long-term irreversible damage. For example, trace amounts of ammonia in the hydrogen feedstock can lead to a significant performance degradation in PEMFCs. Therefore, it is essential to strictly control the content of impurity gases in the hydrogen. Compared to traditional ammonia adsorption strategies, physical adsorption is faster, has lower heat of adsorption, and the adsorbent material is easier to recover, attracting considerable research interest.

[0003] Currently, common ammonia adsorption materials mainly include activated carbon, molecular sieves, metal-organic frameworks, and alkaline earth metal chlorides. Modification of these materials can significantly improve their ammonia adsorption performance. CN101279236A discloses a purification agent prepared by chemical modification with acidic substances using porous materials as carriers. The carriers include type A, X, and Y molecular sieves, activated carbon, and activated alumina, which can be used to adsorb low concentrations of ammonia in industrial waste gas or air. However, the above-mentioned adsorbents cannot fully utilize the active components for trace amounts of ammonia, and the adsorption capacity and depth of ammonia need to be improved. Summary of the Invention

[0004] The purpose of this disclosure is to provide a modified type A molecular sieve, its preparation method, and a method for removing ammonia impurities from hydrogen gas. The modified type A molecular sieve has a high ammonia adsorption capacity and can also effectively adsorb trace amounts of ammonia gas.

[0005] To achieve the above objectives, a first aspect of this disclosure provides a modified type A molecular sieve, comprising a type A molecular sieve and a first metal active component and a second metal active component supported on the type A molecular sieve; the first metal active component comprises Cu. 2+ The second metal active component contains Zn 2+ Based on the total weight of the modified type A molecular sieve, the content of the first metal active component is 6.16~34.95% by weight, and the content of the second metal active component is 3.02~15.56% by weight, wherein the first metal active component and the second metal active component are in the form of metal oxides (ZnO or CuO).

[0006] Optionally, based on the total weight of the modified type A molecular sieve, the content of the first metal active component is 6-11% by weight, preferably 9-11% by weight; the content of the second metal active component is 9-15.56% by weight, preferably 9-14% by weight.

[0007] Optionally, in the modified type A molecular sieve, the weight ratio of the first metal active component to the second metal active component is 1:(0.08~2.60), preferably 1:(1~2).

[0008] A second aspect of this disclosure provides a method for preparing modified type A molecular sieves, comprising the following steps: mixing type A molecular sieve raw materials, a first metal active component precursor, a second metal active component precursor, and water, and performing ion exchange treatment; wherein the first metal active component precursor comprises Cu. 2+ The second metal active component precursor contains Zn 2+ The weight ratio of the type A molecular sieve raw material, the first metal active component precursor, and the second metal active component precursor is 1:(0.07~1.3):(0.03~0.3).

[0009] Optionally, the weight ratio of the type A molecular sieve raw material: the first metal active component precursor: the second metal active component precursor is 1: (0.10~0.3): (0.09~0.16).

[0010] Optionally, the average pore size of the type A molecular sieve raw material is 0.41~0.50 nm, preferably 0.45~0.50 nm; the pore volume is 0.0842~0.2966 cm³. 3 / g, preferably 0.2799~0.2920cm 3 / g; the first metal active component precursor is selected from one or more of CuSO4·5H2O, CuCl2 and Cu(NO3)2, preferably CuSO4·5H2O; the second metal active component precursor is selected from one or more of ZnCl2 and Zn(NO3)2, preferably ZnCl2.

[0011] Optionally, the step of contacting the type A molecular sieve raw material, the first metal active component precursor, the second metal active component precursor, and water for ion exchange treatment is selected from one of the following methods 1 to 3: Method 1: The type A molecular sieve raw material, the first metal active component precursor, and water are mixed, and ion exchange treatment, solid-liquid separation treatment, washing treatment, and drying treatment are performed to obtain an intermediate product; the intermediate product is mixed with the second metal active component precursor and water, and ion exchange treatment, solid-liquid separation treatment, washing treatment, and drying treatment are performed; Method 2: The type A molecular sieve raw material, the second metal active component precursor, and water are contacted for ion exchange treatment, solid-liquid separation treatment, washing treatment, and drying treatment are performed; The precursor is mixed with water and subjected to ion exchange treatment, solid-liquid separation treatment, washing treatment and drying treatment to obtain an intermediate product; the intermediate product is mixed with the first metal active component precursor and water and subjected to ion exchange treatment, solid-liquid separation treatment, washing treatment and drying treatment; Method 3: The type A molecular sieve raw material, the first metal active component precursor, the second metal active component precursor and water are mixed and subjected to ion exchange treatment, solid-liquid separation treatment, washing treatment and drying treatment; Preferably, in Method 1 to Method 3, the weight ratio of water to the type A molecular sieve raw material added in any step is (10~35):1.

[0012] Optionally, the conditions for the ion exchange treatment include: a temperature of 50~100℃ and a time of 50~120min; preferably, a temperature of 80~90℃ and a time of 60~0℃.

[0013] The third aspect of this disclosure provides a modified type A molecular sieve prepared according to the method described in the second aspect of this disclosure.

[0014] The fourth aspect of this disclosure provides a method for removing ammonia impurities from hydrogen gas, comprising the following steps: granulating a modified type A molecular sieve as described in the first or third aspect of this disclosure to obtain a catalyst, wherein the catalyst has a mesh size of 70-120 mesh; activating the catalyst in an inert atmosphere to obtain an activated catalyst; contacting hydrogen gas containing ammonia impurities with the activated catalyst for adsorption treatment; wherein the activated catalyst is used in the form of a fixed adsorption bed.

[0015] Optionally, the activation treatment conditions include: an activation temperature of 200~260℃ and an activation time of 2~5h; preferably, an activation temperature of 230~250℃ and an activation time of 2.5~3h; the inert atmosphere is selected from one or more of nitrogen, argon, and helium, preferably nitrogen and / or argon; preferably, the adsorption treatment conditions include: an adsorption temperature of 20~60℃, an adsorption pressure of 60~110psi, and a gas hourly space velocity of 0.0113~0.0253 min. -1Preferably, the adsorption temperature is 30~40℃, the adsorption pressure is 70~80psi, and the gas hourly space velocity is 0.0117~0.0166min. -1 Optionally, the ammonia impurity content in the hydrogen containing ammonia impurities is 10~1000ppm.

[0016] Through the above technical solutions, this disclosure provides a modified type A molecular sieve, its preparation method, and a method for removing ammonia impurities from hydrogen gas. The modified type A molecular sieve removes Cu in ionic form... 2+ and Zn 2+ Two metal active components are combined with type A molecular sieve to form modified type A molecular sieve. The synthesis steps are simple and easy to industrialize. The obtained molecular sieve has a high loading of active components, high adsorption capacity and removal depth for ammonia, and can be widely used in the removal of trace ammonia in proton exchange membrane fuel cell hydrogen, showing strong industrial application prospects.

[0017] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Attached Figure Description

[0018] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings: Figure 1 is a typical morphology diagram of the modified type A molecular sieve prepared in Example 1 of the present disclosure; Figure 2a is an XPS photoelectron spectroscopy spectrum of zinc ions after activation treatment of the modified type A molecular sieve prepared in Example 1 of the present disclosure; Figure 2b is an XPS Auger spectrum of zinc ions after activation treatment of the modified type A molecular sieve prepared in Example 1 of the present disclosure; Figure 3a is an XPS photoelectron spectroscopy spectrum of copper ions after activation treatment of the modified type A molecular sieve prepared in Example 1 of the present disclosure; Figure 3b is an XPS Auger spectrum of copper ions after activation treatment of the modified type A molecular sieve prepared in Example 1 of the present disclosure. Detailed Implementation

[0019] The following provides a detailed description of specific embodiments of this disclosure. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of this disclosure.

[0020] The first aspect of this disclosure provides a modified type A molecular sieve, the modified type A molecular sieve comprising a type A molecular sieve and a first metal active component and a second metal active component supported on the type A molecular sieve; the first metal active component comprises Cu. 2+ The second metal active component contains Zn 2+Based on the total weight of the modified type A molecular sieve, the content of the first metal active component is 6.16~34.95% by weight, and the content of the second metal active component is 3.02~15.56% by weight, wherein the first metal active component and the second metal active component are in the form of metal oxides.

[0021] This disclosure provides a modified type A molecular sieve, which incorporates Cu... 2+ and Zn 2+ Two metal active components are combined with type A molecular sieves to form modified type A molecular sieves, wherein Cu 2+ and Zn 2+ The modified type A molecular sieve is used as the active center and the carrier. It has a high loading of active components, high adsorption capacity and removal depth of ammonia, and can be widely used in the removal of trace ammonia in proton exchange membrane fuel cell hydrogen. It has strong industrial application prospects.

[0022] In a preferred embodiment, based on the total weight of the modified type A molecular sieve, the content of the first metal active component is 6-11% by weight, preferably 9-11% by weight; the content of the second metal active component is 9-15.56% by weight, preferably 9-14% by weight. The modified type A molecular sieve with the preferred metal active component content provided in this embodiment has a larger adsorption capacity and a better ammonia adsorption effect.

[0023] In a preferred embodiment, the weight ratio of the first active metal component to the second active metal component in the modified type A molecular sieve is 1:0.08~2.60, preferably 1:1~2. When the weight ratio of the two active metal components in the modified type A molecular sieve is within the range of this disclosure, especially within the preferred range, a better synergistic effect can be achieved, increasing the ammonia adsorption capacity.

[0024] In one specific embodiment, the modified type A molecular sieve has an average pore size of 2.15~11.13 nm, preferably 2.35~2.54 nm; and a pore volume of 0.0842~0.2966 cm³. 3 / g, preferably 0.2799~0.2896cm 3 / g; particle size is 1.0~6.0μm, preferably 1.6~3.0μm.

[0025] A second aspect of this disclosure provides a method for preparing modified type A molecular sieves, comprising the following steps: mixing type A molecular sieve raw materials, a first metal active component precursor, a second metal active component precursor, and water, and performing ion exchange treatment; wherein the first metal active component precursor comprises Cu. 2+ The second metal active component precursor contains Zn 2+The weight ratio of the type A molecular sieve raw material, the first metal active component precursor, and the second metal active component precursor is 1:(0.07~1.3):(0.03~0.3).

[0026] This disclosure provides a method for preparing modified type A molecular sieves, which has simple synthesis steps and is easy to industrialize; the modified type A molecular sieves prepared by this method have high active component loading, high adsorption capacity for ammonia and high removal depth.

[0027] In a preferred embodiment, the weight ratio of the type A molecular sieve raw material: the first metal active component precursor: the second metal active component precursor is 1:(0.10~0.3):(0.09~0.16). The modified type A molecular sieve prepared according to the preferred raw material ratio provided in this embodiment can further improve the adsorption effect of the modified type A molecular sieve on ammonia.

[0028] In one embodiment, the average pore size of the type A molecular sieve raw material is 2.15~11.13 nm, preferably 2.35~2.54 nm; the pore volume is 0.0842~0.2966 cm³. 3 / g, preferably 0.2799~0.2896cm 3 / g; particle size is 1.0~6.0μm, preferably 1.6~3.0μm. Using the type A molecular sieve of this embodiment, a modified type A molecular sieve with better ammonia adsorption performance can be obtained.

[0029] In one specific embodiment, the type A molecular sieve is selected from one or more of 5A molecular sieve and 4A.

[0030] In one specific embodiment, the first metal active component precursor is selected from one or more of CuSO4·5H2O, CuCl2, and Cu(NO3)2, preferably CuSO4·5H2O; the second metal active component precursor is selected from one or more of ZnCl2 and Zn(NO3)2, preferably ZnCl2. All raw materials used in this disclosure can be obtained through ordinary commercial channels or prepared by known methods.

[0031] In one embodiment, the contact of the type A molecular sieve raw material, the first metal active component precursor, the second metal active component precursor, and water for ion exchange treatment is selected from one of the following methods 1 to 3: Method 1: The type A molecular sieve raw material, the first metal active component precursor, and water are mixed, and ion exchange treatment, solid-liquid separation treatment, washing treatment, and drying treatment are performed to obtain an intermediate product; The intermediate product is mixed with the second metal active component precursor and water, and ion exchange treatment, solid-liquid separation treatment, washing treatment, and drying treatment are performed; Method 2: The type A molecular sieve raw material, the second metal active component precursor, and water are contacted for ion exchange treatment, solid-liquid separation treatment, washing treatment, and drying treatment; Method 2: The type A molecular sieve raw material, the second metal active component precursor, and water are contacted for ion exchange treatment, solid-liquid separation treatment, washing treatment, and drying treatment; Method 3: The type A molecular sieve raw material, the first metal active component precursor, and water are contacted for ion exchange treatment, solid-liquid separation treatment, washing treatment, and drying treatment; Method 4: The type A molecular sieve raw material, the second metal active component precursor, and water are contacted for ion exchange treatment, solid-liquid separation treatment, washing treatment, and drying treatment; Method 5: The type A molecular sieve raw material, the second metal active component precursor, and water are contacted for ion exchange treatment, solid-liquid separation treatment, washing treatment, and drying treatment; Method 6: The type A molecular sieve raw material, the first metal active component precursor, and water are contacted for ion exchange treatment, solid-liquid separation treatment, washing treatment, and drying treatment; Method 7: The type A molecular sieve raw material, the first metal active component precursor, and water are contacted for ion exchange treatment, solid-liquid separation treatment, washing treatment, and drying treatment; Method 8: The type A molecular sieve raw material, the first metal active component precursor, and water are contacted for ion exchange treatment, solid-liquid separation The precursor is mixed with water and subjected to ion exchange, solid-liquid separation, washing, and drying to obtain an intermediate product. The intermediate product is then mixed with the first metal active component precursor and water, and subjected to ion exchange, solid-liquid separation, washing, and drying. Alternatively, in method 3, the type A molecular sieve raw material, the first metal active component precursor, the second metal active component precursor, and water are mixed and subjected to ion exchange, solid-liquid separation, washing, and drying. Preferably, in methods 1 to 3, the weight ratio of water to the type A molecular sieve raw material in any step is (10-35):1. The solid-liquid separation can be performed using conventional methods such as vacuum filtration.

[0032] This disclosure allows for the loading of two metal active components onto type A molecular sieves in various ion exchange treatment sequences, with a simple and easy-to-implement process.

[0033] In one embodiment, the ion exchange treatment conditions include: a temperature of 50-100°C and a time of 50-120 min; preferably, a temperature of 80-90°C and a time of 60-80°C. Following the treatment conditions of this embodiment, especially the preferred conditions, a better ion exchange effect can be obtained.

[0034] The third aspect of this disclosure provides a modified type A molecular sieve prepared according to the method described in the second aspect of this disclosure.

[0035] The fourth aspect of this disclosure provides a method for removing ammonia impurities from hydrogen gas, comprising the following steps: granulating a modified type A molecular sieve as described in the first or third aspect of this disclosure to obtain a catalyst, wherein the catalyst has a mesh size of 70-120 mesh; activating the catalyst in an inert atmosphere to obtain an activated catalyst; contacting hydrogen gas containing ammonia impurities with the activated catalyst for adsorption treatment; wherein the activated catalyst is used in the form of a fixed adsorption bed.

[0036] This disclosure provides a method for removing ammonia impurities from hydrogen. The modified type A molecular sieve used has high adsorption capacity and removal depth for ammonia, and can be widely used for the removal of trace amounts of ammonia in proton exchange membrane fuel cell-grade hydrogen, showing strong industrial application prospects.

[0037] In a preferred embodiment, the activation treatment conditions include: an activation temperature of 200-260°C and an activation time of 2-5 hours; preferably, the activation temperature is 230-250°C and the activation time is 2.5-3 hours; the inert atmosphere is selected from one or more of nitrogen, argon, and helium, preferably nitrogen and / or argon. According to the process conditions in this embodiment, especially the preferred process conditions, the modified type A molecular sieve can be effectively activated, improving its subsequent ammonia adsorption effect.

[0038] In one embodiment, the conditions for the adsorption treatment include: an adsorption temperature of 20–60°C, an adsorption pressure of 60–110 psi, and a gas hourly space velocity of 0.0113–0.0253 min. -1 Preferably, the adsorption temperature is 30~40℃, the adsorption pressure is 70~80psi, and the gas hourly space velocity is 0.0117~0.0166min. -1 The adsorption treatment method provided in this disclosure has a low adsorption temperature, allowing the adsorbent to fully contact the gas. Furthermore, the adsorption treatment conditions provided in this embodiment, especially the preferred adsorption treatment conditions, help to improve the removal of ammonia from hydrogen.

[0039] In one specific embodiment, the ammonia impurity content in the hydrogen containing ammonia is 10~1000ppm.

[0040] The present disclosure is further described in detail below through examples. All raw materials used in the examples are commercially available.

[0041] I. Instrument magnetic stirring equipment (DF-101S heat-collecting magnetic heating stirrer manufactured by Jiangsu Jinyi Instrument Technology Co., Ltd.)

[0042] Vacuum filtration equipment with Buchner funnel and filtration flask (SHZ-D(III) type circulating water vacuum pump manufactured by Gongyi Yuhua Instrument Co., Ltd.).

[0043] II. The raw material, type A molecular sieve, was of analytical grade and purchased from Nankai University (the average pore size of the type A molecular sieve raw material was 0.50 nm; the pore volume was 0.2918 cm³). 3 / g); ion exchange modification with Cu 2+ The soluble salts were analytical grade and purchased from Beijing Yili Fine Chemicals Co., Ltd.; the ion exchange modification used Zn-containing... 2+The soluble salts were chemically pure and purchased from Beijing Innocare Technology Co., Ltd.; ammonia (1000ppm) - air was purchased from Sichuan Zhongce Standard Technology Co., Ltd.

[0044] III. Detection Method of Modified Type A Molecular Sieves Chemical composition of modified type A molecular sieves: The chemical composition was determined using a ZSX100E X-ray fluorescence spectrometer from Rigaku Corporation, Japan, with a tube voltage of 40kV and a tube current of 250mA. Elemental analysis was performed based on the relationship that the intensity of fluorescence rays of each element is proportional to its concentration.

[0045] Microstructure of modified type A molecular sieve: determined using a Hitachi S4800 scanning electron microscope (SEM) with an accelerating voltage of 5 kV, a working distance of 8 mm, and a magnification of 1 k to 2 k.

[0046] The valence states of metal ions in the modified type A molecular sieve were determined using Al Ka ​​radiation on a Thermo Fischer-VG ESCALAB 250 spectrometer. The Al 2p peak with a binding energy of 74.7 eV was used to calibrate the binding energy scale.

[0047] IV. Exhaust Gas Detection Method: The ammonia adsorption capacity of the modified bimetallic type A molecular sieve can be measured using the cavity ring-down method. The results were obtained using a spectroscopic gas analyzer from Guangneng Technology Co., Ltd., at room temperature. The test method references standard TB-20210077, "Determination of Ammonia in Hydrogen - Cavity Ring-Down Spectrometry".

[0048] Example 1: 10g of 5A molecular sieve (Type A molecular sieve raw material) and 2.97g of CuSO4·5H2O (precursor of the first metal active component) were added to 200mL of deionized water and subjected to ion exchange for 60min in an 80℃ water bath (weight ratio of Type A molecular sieve raw material to water was 1:20). The mixture was filtered, washed with deionized water until neutral, and dried at 100℃. Then, 10g of the dried sample, 1.6g of ZnCl2 (precursor of the second metal active component), and 150mL of deionized water were weighed and subjected to ion exchange for 60min in an 80℃ water bath (weight ratio of Type A molecular sieve raw material to water was 1:15). The mixture was filtered, washed with deionized water until neutral, and dried at 100℃ to obtain modified Type A molecular sieve. The weight ratio of Type A molecular sieve raw material: first metal active component precursor: second metal active component precursor was 1:0.297:0.16.

[0049] Figure 1 shows an SEM image of the modified type A molecular sieve prepared in this embodiment. As can be seen from Figure 1, the modified type A molecular sieve prepared in this embodiment has uniform particle size.

[0050] Example 2: 10g of 5A molecular sieve (Type A molecular sieve raw material) and 3.95g of CuSO4·5H2O (precursor of the first metal active component) were added to 200mL of deionized water and subjected to ion exchange for 60min in an 80℃ water bath (the weight ratio of Type A molecular sieve raw material to water was 1:20). The mixture was filtered, washed with deionized water until neutral, and dried at 100℃. Then, 10g of the dried sample, 1.1g of ZnCl2 (precursor of the second metal active component), and 200mL of deionized water were weighed and subjected to ion exchange for 60min in an 80℃ water bath (the weight ratio of Type A molecular sieve raw material to water was 1:20). The mixture was filtered, washed with deionized water until neutral, and dried at 100℃ to obtain modified Type A molecular sieve. The weight ratio of Type A molecular sieve raw material: first metal active component precursor: second metal active component precursor was 1:0.395:0.11.

[0051] In Example 3, 10g of 5A molecular sieve (Type A molecular sieve raw material) and 1.98g of CuSO4·5H2O (precursor of the first metal active component) were added to 200mL of deionized water and subjected to ion exchange for 60min in an 80℃ water bath (the weight ratio of Type A molecular sieve raw material to water was 1:20). The mixture was filtered, washed with deionized water until neutral, and dried at 100℃. Then, 10g of the dried sample, 2.15g of ZnCl2 (precursor of the second metal active component), and 250mL of deionized water were weighed and subjected to ion exchange for 60min in an 80℃ water bath (the weight ratio of Type A molecular sieve raw material to water was 1:25). The mixture was filtered, washed with deionized water until neutral, and dried at 100℃ to obtain modified Type A molecular sieve. The weight ratio of Type A molecular sieve raw material: first metal active component precursor: second metal active component precursor was 1:0.198:0.215.

[0052] Example 4 This example refers to the preparation method in Example 1, except that the raw material addition ratio is changed so that the weight ratio of type A molecular sieve raw material: first metal active component precursor: second metal active component precursor is 1:1.3:1.02. The rest of the process is the same as in Example 1, and modified type A molecular sieve is prepared.

[0053] In Example 5, 10 g of 5A molecular sieve (Type A molecular sieve raw material), 2.97 g of CuSO4·5H2O (first metal active component precursor), and 1.6 g of ZnCl2 (second metal active component precursor) were added to 350 mL of deionized water for ion exchange at 80 °C for 60 min. The mixture was then filtered, washed with deionized water until neutral, and dried at 100 °C to obtain modified Type A molecular sieve. The weight ratio of Type A molecular sieve raw material: first metal active component precursor: second metal active component precursor was 1:0.297:0.16, and the weight ratio of Type A molecular sieve raw material to water was 1:35.

[0054] In Example 6, 10g of 5A molecular sieve (Type A molecular sieve raw material) and 1.6g of ZnCl2 (precursor of the second metal active component) were added to 200mL of deionized water and subjected to ion exchange for 60min at 80℃ (weight ratio of Type A molecular sieve raw material to water was 1:20). The mixture was filtered, washed with deionized water until neutral, and dried at 100℃. Then, 10g of the dried sample, 2.97g of CuSO4·5H2O (precursor of the first metal active component), and 150mL of deionized water were weighed and subjected to ion exchange for 60min at 80℃ (weight ratio of Type A molecular sieve raw material to water was 1:15). The mixture was filtered, washed with deionized water until neutral, and dried at 100℃ to obtain modified Type A molecular sieve. The weight ratio of Type A molecular sieve raw material: first metal active component precursor: second metal active component precursor was 1:0.297:0.16.

[0055] Comparative Example 1: This comparative example does not include a second metal active component precursor and includes the following steps: 10 g of 5A molecular sieve and 5.94 g of CuSO4·5H2O are added to 200 mL of deionized water and ion exchange is carried out in an 80 °C water bath for 60 min. The mixture is then filtered and washed with deionized water until neutral, and dried at a constant temperature of 100 °C to obtain copper ion exchange type A molecular sieve.

[0056] Comparative Example 2: No precursor of the first metal active component was added in this comparative example. The steps included: 10g of 5A molecular sieve and 3.2g of ZnCl2 were added to 200mL of deionized water and ion exchange was carried out in an 80℃ water bath for 60min. The mixture was then filtered and washed with deionized water until neutral. It was then dried at a constant temperature of 100℃ to obtain zinc ion exchange type A molecular sieve.

[0057] Comparative Example 3: No molecular sieve was modified in this comparative example; only 5A molecular sieve (analytical grade, purchased from Nankai University) was used.

[0058] Comparative Example 4: The preparation method of Comparative Example 4 is the same as that in Example 1, except that the ratio of raw materials added is changed so that the weight ratio of A-type molecular sieve raw material: first metal active component precursor: second metal active component precursor is 1:0.1:0.1. The rest of the process is the same as in Example 1, and modified A-type molecular sieve is prepared.

[0059] The component contents of the modified molecular sieve products prepared in the above examples and comparative examples are listed in Table 1 below.

[0060] Table 1

[0061] Test Example 1 This test example illustrates the adsorption effect of the molecular sieve product provided in this disclosure in a method for removing ammonia impurities from hydrogen gas. It includes the following steps: first, granulating the molecular sieve to obtain a catalyst with a mesh size of 80 mesh; then, activating the catalyst in an inert atmosphere under the following conditions: activation temperature of 240°C, activation time of 2.5 h; nitrogen atmosphere; contacting hydrogen gas containing ammonia impurities with the activated catalyst for adsorption treatment; wherein the activated catalyst is used in the form of a fixed adsorption bed; the ammonia impurity content in the hydrogen gas is 1000 ppm; the adsorption treatment conditions include: adsorption temperature of 35°C, adsorption pressure of 75 psi, and gas hourly space velocity of 0.0152 min⁻¹. -1 The test results are listed in Table 2 below.

[0062] Figures 2a-2b show XPS spectra of zinc ions after activation of the molecular sieve prepared in Example 1. In the photoelectron spectroscopy spectrum of Figure 2a, the activated molecular sieve has a characteristic peak at 1021.3 eV, indicating the presence of zinc ions and elemental zinc. Combined with the Auger peak at 988 eV in Figure 2b, this indicates the presence of zinc ions. Figures 3a-3b show XPS spectra of copper ions after activation of the molecular sieve prepared in Example 1. In the photoelectron spectroscopy spectrum of Figure 3a, the activated molecular sieve has satellite peaks between 940 eV and 950 eV. Combined with the Auger peak in Figure 3b, this indicates the presence of divalent copper ions.

[0063] The above content indicates that the modified type A molecular sieve provided in this disclosure has active centers of divalent copper ions and divalent zinc ions.

[0064] Test Example 2 uses the modified molecular sieve from Example 4 for granulation, following the method of Test Example 1. The difference from Test Example 1 is that the ammonia impurity content in the hydrogen containing ammonia impurities is 10 ppm. The rest of the process is the same as Test Example 1. The test results are listed in Table 2 below.

[0065] Test Example 3 uses the modified molecular sieve from Example 4 for granulation, referring to the method of Test Example 1. The difference from Test Example 1 is that the activation conditions include: activation temperature of 200°C and activation time of 2.5 h; inert atmosphere of nitrogen to obtain activated catalyst; the rest of the process is the same as Test Example 1. The test results are listed in Table 2 below.

[0066] Test Example 4 used the modified molecular sieve from Example 4 for granulation, following the method of Test Example 1, except that the adsorption conditions included: an adsorption temperature of 60°C, an adsorption pressure of 60 psi, and a gas hourly space velocity of 0.0253 min⁻¹. -1The rest of the process is the same as in Test Example 1. The test results are listed in Table 2 below.

[0067] Table 2

[0068] Based on the data in Tables 1-2, it can be seen that: in Test Example 1, the molecular sieves in Comparative Examples 1-2 only loaded one of the active metal components, Cu and Zn; the molecular sieve in Comparative Example 3 did not load any active metal component. Compared to Comparative Examples 1-3, the modified type A molecular sieves provided in Examples 1-6 simultaneously loaded the first and second active metal components, exhibiting a synergistic effect and significantly increasing ammonia adsorption capacity. In Comparative Example 4, the content of the first active metal component in the modified type A molecular sieve was outside the range provided in this disclosure. Compared to Comparative Example 4, the ammonia adsorption capacity of the modified type A molecular sieves provided in Examples 1-6 was significantly improved. Comparing Example 3 with Examples 2 and 4, the content of the first and second active metal components in the modified molecular sieve in Example 3 is 6-11 g / L, which is within the range of the content of the first active metal component provided in this disclosure. Within the preferred range of "the content of the first metal active component is 9-15.56% by weight", the molecular sieve obtained in Example 3 has a higher ammonia adsorption capacity. Comparing Example 1 and Example 3, the content of the first metal active component and the second metal active component in the modified molecular sieve in Example 1 is within the further preferred range of "the content of the first metal active component is 9-11% by weight and the content of the second metal active component is 9-14% by weight" provided in this disclosure. The molecular sieve obtained in Example 1 has a higher ammonia adsorption capacity. As can be seen from Test Example 2, the modified type A molecular sieve provided in this disclosure can also effectively adsorb ammonia impurities of 10 ppm. According to the comparison between Test Example 1 and Test Examples 3-4, it can be seen that the preferred activation treatment conditions and preferred adsorption conditions provided in this disclosure in Example 1 can obtain a better ammonia adsorption effect.

[0069] The preferred embodiments of this disclosure have been described in detail above. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0070] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0071] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A modified type A molecular sieve, characterized in that, The modified type A molecular sieve includes a type A molecular sieve and a first metal active component and a second metal active component supported on the type A molecular sieve; the first metal active component contains Cu. 2+ The second metal active component contains Zn 2+ Based on the total weight of the modified type A molecular sieve, the content of the first metal active component is 6.16~34.95% by weight, and the content of the second metal active component is 3.02~15.56% by weight, wherein the first metal active component and the second metal active component are in the form of metal oxides.

2. The modified type A molecular sieve according to claim 1, characterized in that, Based on the total weight of the modified type A molecular sieve, the content of the first metal active component is 6-11% by weight, preferably 9-11% by weight; the content of the second metal active component is 9-15.56% by weight, preferably 9-14% by weight.

3. The modified type A molecular sieve according to claim 1, characterized in that, In the modified type A molecular sieve, the weight ratio of the first metal active component to the second metal active component is 1:(0.08~2.60), preferably 1:(1~2).

4. A method for preparing modified type A molecular sieves, characterized in that, Includes the following steps: A type A molecular sieve raw material, a first metal active component precursor, a second metal active component precursor, and water are mixed and subjected to ion exchange treatment; wherein, the first metal active component precursor contains Cu. 2+ The second metal active component precursor contains Zn 2+ The weight ratio of the type A molecular sieve raw material, the first metal active component precursor, and the second metal active component precursor is 1:(0.07~1.3):(0.03~0.3).

5. The method according to claim 4, characterized in that, The weight ratio of the type A molecular sieve raw material, the first metal active component precursor, and the second metal active component precursor is 1:(0.10~0.3):(0.09~0.16).

6. The method according to claim 4, characterized in that, The type A molecular sieve raw material has an average pore size of 0.41~0.50 nm, preferably 0.45~0.50 nm; and a pore volume of 0.0842~0.2966 cm³. 3 / g, preferably 0.2799~0.2920cm 3 / g; the first metal active component precursor is selected from one or more of CuSO4·5H2O, CuCl2 and Cu(NO3)2, preferably CuSO4·5H2O; the second metal active component precursor is selected from one or more of ZnCl2 and Zn(NO3)2, preferably ZnCl2.

7. The method according to claim 4, characterized in that, The process of contacting the type A molecular sieve raw material, the first metal active component precursor, the second metal active component precursor, and water for ion exchange treatment is selected from one of the following methods 1 to 3: Method 1: The type A molecular sieve raw material, the first metal active component precursor, and water are mixed, and ion exchange treatment, solid-liquid separation treatment, washing treatment, and drying treatment are performed to obtain an intermediate product; the intermediate product is mixed with the second metal active component precursor and water, and ion exchange treatment, solid-liquid separation treatment, washing treatment, and drying treatment are performed; Method 2: The type A molecular sieve raw material, the second metal active component precursor, and water are mixed, and ion exchange treatment, solid-liquid separation treatment, washing treatment, and drying treatment are performed; The intermediate product is obtained by mixing with water, undergoing ion exchange treatment, solid-liquid separation treatment, washing treatment, and drying treatment; the intermediate product is then mixed with the first metal active component precursor and water, and subjected to ion exchange treatment, solid-liquid separation treatment, washing treatment, and drying treatment; Method 3: The A-type molecular sieve raw material, the first metal active component precursor, the second metal active component precursor, and water are mixed, and subjected to ion exchange treatment, solid-liquid separation treatment, washing treatment, and drying treatment; Preferably, in Methods 1 to 3, the weight ratio of water to the A-type molecular sieve raw material in any step is (10~35):

1.

8. The method according to claim 4, characterized in that, The conditions for the ion exchange treatment include: a temperature of 50~100℃ and a time of 50~120min; preferably, a temperature of 80~90℃ and a time of 60~0℃.

9. The modified type A molecular sieve prepared by the method according to any one of claims 4 to 8.

10. A method for removing ammonia impurities from hydrogen gas, characterized in that, Includes the following steps: The modified type A molecular sieve as described in any one of claims 1 to 3 and 9 is granulated to obtain a catalyst, wherein the catalyst has a mesh size of 70 to 120 mesh; the catalyst is activated in an inert atmosphere to obtain an activated catalyst; hydrogen containing ammonia impurities is contacted with the activated catalyst for adsorption treatment. The activated catalyst is used in the form of a fixed adsorption bed.

11. The method according to claim 10, characterized in that, The activation treatment conditions include: an activation temperature of 200~260℃ and an activation time of 2~5h; preferably, an activation temperature of 230~250℃ and an activation time of 2.5~3h; the inert atmosphere is selected from one or more of nitrogen, argon, and helium, preferably nitrogen and / or argon; preferably, the adsorption treatment conditions include: an adsorption temperature of 20~60℃, an adsorption pressure of 60~110psi, and a gas hourly space velocity of 0.0113~0.0253 min. -1 Preferably, the adsorption temperature is 30~40℃, the adsorption pressure is 70~80psi, and the gas hourly space velocity is 0.0117~0.0166min. -1 Optionally, the ammonia impurity content in the hydrogen containing ammonia impurities is 10~1000ppm.

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