A fe-based aluminophosphate-based co2 adsorbent and a method of making the same

Abstract

The application relates to the technical field of carbon dioxide capture, in particular to a CO2 adsorbent based on Fe-based aluminophosphate and a preparation method thereof. The preparation method comprises the following steps: 1) mixing aluminum isopropoxide with water, dissolving under stirring, and then sequentially adding orthophosphoric acid and a structure directing agent to form a reaction gel; 2) adding a Fe precursor solution and additional water into the reaction gel obtained in the step 1) to form a doped system; wherein the aluminum isopropoxide is converted into Al2O3 at the mole number of aluminum atoms, and the mole ratio of the additional water to Al2O3 is 100-250:1; 3) carrying out hydrothermal reaction on the doped system obtained in the step 2) in a reaction kettle to obtain Fe-doped ALPO crystals; and 4) continuously activating the Fe-doped ALPO crystals obtained in the step 3) to obtain the CO2 adsorbent based on Fe-based aluminophosphate. The application solves the problems of the CO2 adsorbent in the prior art in the aspects of adsorption capacity, adsorption kinetics, thermal stability and chemical stability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of carbon dioxide capture, in particular to a CO2 adsorbent based on Fe-based aluminophosphate and a preparation method thereof. BACKGROUND

[0002] With the acceleration of global industrialization, the emission of carbon dioxide (CO2) continues to increase, leading to the intensification of the greenhouse effect. In order to slow down climate change, CO2 capture, utilization and storage (CCUS) technology has become a key means to reduce the content of greenhouse gases in the atmosphere. In the CCUS technology, CO2 adsorption technology is of great concern due to its high efficiency and operability. Traditional CO2 adsorption materials include physical adsorbents (such as porous carbon, zeolites and metal-organic frameworks) and chemical adsorbents (such as functionalized materials containing amine groups). However, these materials have a series of problems in practical application, such as limited adsorption capacity, low selectivity, slow kinetics and performance decline in humid environment, etc.

[0003] Aluminophosphate, due to its unique one-dimensional parallel microporous structure and neutral surface characteristics, is considered as a potential CO2 adsorbent. ALPO is composed of alternating Al 3+ and P 5+ atoms connected by oxygen atoms, with a charge-neutral framework structure, so that the material only shows slight hydrophilicity. This structural feature makes ALPO have potential advantages in CO2 adsorption, especially in the process of rapid pressure swing adsorption (PSA), with longer stability and life cycle of adsorption / desorption cycles.

[0004] However, the preparation and activation methods of ALPO in the prior art still have some limitations, such as complex preparation process of adsorbent, high cost, unstable adsorption performance, etc. Therefore, it is necessary to develop a new efficient CO2 adsorbent based on aluminophosphate modification and its preparation and activation method to solve the problems existing in the prior art and improve the efficiency and economy of CO2 capture. Based on this demand, the present application provides a new efficient CO2 adsorbent based on aluminophosphate modification and its preparation and activation method, aiming to provide a CO2 adsorbent with high adsorption capacity, fast adsorption kinetics, good thermal stability and chemical stability to meet the demand of industrial-scale CO2 capture. SUMMARY

[0005] In view of the above-mentioned shortcomings of the prior art, the purpose of the present application is to provide a CO2 adsorbent based on Fe-based aluminophosphate and a preparation method thereof to solve the limitations of the CO2 adsorbent in adsorption capacity, adsorption kinetics, thermal stability and chemical stability as mentioned in the background art.

[0006] To achieve the above object and other related objects, the present application is obtained by the following technical solutions.

[0007] The present application provides a preparation method of a CO2 adsorbent based on Fe-based aluminophosphate, comprising the following steps:

[0008] 1) mixing aluminum isopropoxide with water, dissolving under stirring, and then sequentially adding orthophosphoric acid and a structure directing agent to form a reaction gel;

[0009] 2) adding a Fe precursor solution and additional water to the reaction gel obtained in step 1) to form a doped system; wherein the aluminum isopropoxide is converted to Al2O3 in terms of the number of aluminum atoms, and the molar ratio of additional water to Al2O3 is 100-250:1.

[0010] 3) subjecting the doped system obtained in step 2) to a hydrothermal reaction in a reaction kettle to obtain a Fe-doped ALPO crystal;

[0011] 4) continuing to activate the Fe-doped ALPO crystal obtained in step 3) to obtain a CO2 adsorbent based on Fe-based aluminophosphate.

[0012] The present application also provides a CO2 adsorbent based on Fe-based aluminophosphate, which is prepared by the preparation method of a CO2 adsorbent based on Fe-based aluminophosphate as described above.

[0013] Compared with the prior art, the present application has the following beneficial effects:

[0014] 1. Significant improvement in adsorption capacity: The present application uses precise metal doping technology and crystal morphology control, so that the adsorbent exhibits CO2 adsorption capacity exceeding traditional AlPO at various test pressures. This improvement not only enhances the application range of the adsorbent, but also provides a more efficient solution for industrial-scale CO2 capture.

[0015] 2. Optimization of adsorption kinetics: The adsorbent of the present application follows a pseudo-first-order model for CO2 adsorption, which means that the adsorption process is not only fast but also easy to control. Optimized kinetic performance enables the adsorbent to reach adsorption equilibrium faster, improving the efficiency of the adsorption process.

[0016] 3. Excellent thermal and chemical stability: The adsorbent of the present application remains stable even at high temperatures, which makes it very suitable for industrial applications, especially in situations that require operation in high-temperature environments.

[0017] 4, The adsorbent of the present application has an adsorption heat of not higher than 25 kJ / mol, which is a low adsorption heat characteristic that is advantageous for desorption of CO2 by rapid pressure swing adsorption (PSA) without an additional heat regeneration step. This advantage not only reduces energy consumption, but also simplifies the regeneration process of the adsorbent, improving the overall operation efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 SEM image of 5Fe-AlPO under the condition of a water / Al2O3 molar ratio of 400:1 in Comparative Example 1.

[0019] Figure 2 SEM image of 5Fe-AlPO under the condition of a water / Al2O3 molar ratio of 100:1 in Example 1. DETAILED DESCRIPTION

[0020] Hereinafter, embodiments of the present application, which specifically disclose a Fe-based aluminophosphate-based CO2 adsorbent and a method for producing the same, will be explained in detail with appropriate reference to the accompanying drawings. However, there will be cases where unnecessary detailed explanations are omitted. For example, there will be cases where detailed explanations of matters that are already well known, repeated explanations of actually identical structures are omitted. This is in order to avoid the following description from becoming unnecessarily lengthy and to facilitate understanding by those skilled in the art. In addition, the accompanying drawings and the following explanations are provided in order for those skilled in the art to fully understand the present application, and are not intended to limit the subject matter recited in the claims.

[0021]

Method for producing Fe-based aluminophosphate-based CO2 adsorbent

[0022] The present application provides a method for producing a Fe-based aluminophosphate-based CO2 adsorbent, the method comprising the following steps:

[0023] 1) mixing aluminum isopropoxide with water, dissolving under stirring, and then sequentially adding orthophosphoric acid and a structure directing agent to form a reaction gel;

[0024] 2) adding a Fe precursor solution and additional water to the reaction gel obtained in step 1) to form a doped system;

[0025] 3) subjecting the doped system obtained in step 2) to a hydrothermal reaction in a reaction vessel to obtain a Fe-doped ALPO crystal;

[0026] 4) further activating the Fe-doped ALPO crystal obtained in step 3) to obtain a Fe-based aluminophosphate-based CO2 adsorbent.

[0027] In the production method according to the present application, step 1) is mixing aluminum isopropoxide with water, dissolving under stirring, and then sequentially adding orthophosphoric acid and a structure directing agent to form a reaction gel. Specifically:

[0028] The basic reaction of aluminum isopropyl oxide hydrolysis can be represented as: 2Al(OiPr3) + 6H2O → Al2O3 + 6OiPrH.

[0029] In step 1) of this invention, aluminum isopropyl oxide is mixed with water and stirred for 2 to 4.5 hours, optionally 2 to 3 hours or 3 to 4.5 hours. The stirring time is used to ensure complete dissolution.

[0030] In step 1) of this invention, the structure directing agent is one or more of triethylamine, tetraethylammonium hydroxide, and cyclohexylamine.

[0031] In step 1) of this invention, the molar ratio of aluminum isopropoxide, orthophosphoric acid, and the structure-directing agent is 1:0.7-1.1:0.6-1.0. Optionally, the molar ratio of aluminum isopropoxide, orthophosphoric acid, and the structure-directing agent is 1:0.7-0.802:0.6-1.0, 1:0.802-1.1:0.6-1.0, 1:0.7-1.1:0.6-0.74, or 1:0.7-1.1:0.74-1.0.

[0032] In step 1) of this invention, the orthophosphoric acid and the structure directing agent are added dropwise.

[0033] In step 1) of this invention, after adding the orthophosphoric acid, the mixture is stirred for 0.75 to 1.75 hours, optionally 0.75 to 1 hour or 1 to 1.75 hours. For example, orthophosphoric acid is added dropwise while stirring continues to form a homogeneous reaction solution.

[0034] In step 1) of this invention, the structure guiding agent is added and then stirred for 18 to 30 hours, which can be selected as 18 to 24 hours or 24 to 30 hours.

[0035] In step 1) of this invention, the pH value of the reaction gel is 5 to 6.

[0036] In one specific embodiment, triethylamine (TEA), as a structure directing agent, is added dropwise and stirred for 24 hours to form a reactive gel with a pH of 5 to 6.

[0037] In the preparation method provided by the present invention, step 2) involves adding Fe precursor solution and water to the reaction gel obtained in step 1) to form a doping system.

[0038] In step 2) of this invention, the aluminum isopropyl oxide is converted to Al2O3 based on the molar number of aluminum atoms, and the molar ratio of water to Al2O3 is 100-250:1, optionally 100-150:1, 150-250:1, etc. Within the aforementioned range, fine control of the crystal morphology of the Fe-based aluminum phosphate-based CO2 adsorbent is achieved. The crystal morphology of the Fe-based aluminum phosphate-based CO2 adsorbent is a spherical aggregate, optimizing the pore structure of the adsorbent. However, if the above range is exceeded, for example, when the molar ratio of water to Al2O3 is 400:1, columnar single crystals are obtained. The crystal morphology and pore characteristics of AlPO obtained under different synthesis conditions are analyzed in detail by SEM and nitrogen adsorption-desorption isotherm tests. The results showed that low water content (e.g., a water / Al2O3 molar ratio of 400:1) led to the formation of columnar crystals, while high water content (e.g., a water / Al2O3 molar ratio of 100:1) resulted in the formation of spherical aggregates, the latter exhibiting a higher CO2 adsorption capacity.

[0039] In step 2) of this invention, the aluminum isopropoxide is converted to Al2O3 based on the molar number of aluminum atoms, and the Fe precursor solution is converted to Fe based on the molar number of iron atoms. The molar ratio of Fe to Al2O3 is 4:100 to 6.5:100. It can be selected as 4:100 to 5:100 or 5:100 to 6.5:100. Within the above range, the Fe metal precursor is doped into ALPO to optimize its lattice parameters and pore structure, thereby improving its CO2 adsorption performance.

[0040] In step 2) of this invention, the Fe precursor solution is selected from one or more of iron(IID) nitrate nonahydrate, iron(I) acetylacetone, or iron(III) porphyrin.

[0041] In the preparation method provided by this invention, step 3) involves carrying out a hydrothermal reaction of the doped system obtained in step 2) in a reactor to obtain Fe-doped ALPO crystals. Specifically:

[0042] In step 3) of this invention, the temperature of the hydrothermal reaction is 130-200℃, which can be selected as 130-160℃ or 160-200℃.

[0043] In step 3) of this invention, the hydrothermal reaction time is 20-30 hours, which can be 20-24 hours or 24-30 hours.

[0044] In step 3) of the present invention, the reaction vessel is a high-pressure vessel, for example, a stainless steel high-pressure vessel lined with polytetrafluoroethylene.

[0045] In a specific embodiment, the doped system was then transferred to a polytetrafluoroethylene-lined stainless steel autoclave and kept at 160°C for 24 hours to promote the growth of Fe-doped ALPO crystals.

[0046] In the preparation method provided by this invention, step 4) involves further activating the Fe-doped ALPO crystal obtained in step 3) to obtain a CO2 adsorbent based on Fe-based aluminum phosphate. Specifically:

[0047] In step 4) of this invention, the activation includes calcination and pyrolysis.

[0048] In step 4) of this invention, the temperature and time parameters of the calcination activation method were optimized in detail. The calcination process was carried out in air at a temperature of 125–525°C and a time of 1.5–3.5 hours to remove the structure-directing agent and fully open the pores. Optionally, the calcination time could be, for example, 125–250°C, 250–400°C, 400–525°C, 250–450°C, or 450–525°C. The calcination time could be, for example, 1.5–2.5 hours or 2.5–3.5 hours. During calcination, the temperature gradually increased from 125–525°C, then the temperature range was gradually narrowed until the optimal calcination activation temperature was found; the time gradually increased from 1 hour to 3.5 hours, then the calcination time range was gradually narrowed until the optimal calcination time was found. Experimental results showed that the sample calcined at 450°C for 2.5 hours exhibited a higher CO2 adsorption capacity.

[0049] In step 4) of this invention, the temperature and pressure parameters of the pyrolysis activation method were optimized in detail. The pyrolysis was carried out under a nitrogen atmosphere, with a pyrolysis temperature of 200–475°C and a pressure of 0.1–2.0 bar, further optimizing the pore structure. Optionally, the pyrolysis temperature could be, for example, 200–300°C, 300–400°C, or 400–475°C. The pressure could be, for example, 0.1–1.0 bar or 1–2.0 bar. During the pyrolysis process, the temperature gradually increased from 200°C to 475°C, and then the temperature range was gradually narrowed until the optimal pyrolysis activation temperature was found. The pressure gradually increased from 0.1 bar to 2.0 bar, and then the pyrolysis pressure range was gradually narrowed until the optimal pyrolysis pressure was found. Experimental results show that the sample at 210°C and 0.35 bar exhibited a higher CO2 adsorption capacity.

[0050] As a further aspect of the invention, the adsorbent exhibits excellent thermal and chemical stability as evaluated by improved thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Specifically, the invention proposes to comprehensively evaluate the thermal and chemical stability of the adsorbent by employing improved TGA conditions, namely, heating from room temperature to 950°C at a heating rate of 5°C / min under an oxygen flow rate of 50 mL / min. Furthermore, differential scanning calorimetry (DSC) is combined to simultaneously monitor the heat flow changes of the adsorbent during the heating process, thereby obtaining more comprehensive data on thermal behavior and chemical stability.

[0051] As a further aspect of this invention, the adsorption isotherm data of the adsorbent under different temperature and pressure conditions are used to calculate the isothermal heat using the Clausius-Clapeyron equation to obtain more accurate adsorption heat data. Specifically, this invention proposes collecting adsorption isotherm data at multiple different temperatures of 25℃, 30℃, 35℃, 40℃, and 45℃, and calculating the isothermal heat using the Clausius-Clapeyron equation to obtain more accurate adsorption heat data. Simultaneously, statistical analysis is performed on the adsorption heat data at different temperatures to evaluate the thermodynamic properties of the adsorption process and the performance stability of the adsorbent.

[0052] As a further aspect of this invention, the adsorbent exhibits excellent regeneration performance and cycling stability in simulated real-world pressure swing adsorption (PSA) processes. Specifically, this invention proposes introducing multiple adsorption-desorption cycle tests under different pressure and temperature conditions during the simulated real-world PSA process to evaluate the regeneration performance and cycling stability of the adsorbent under different operating conditions. By quantitatively analyzing the change in adsorption capacity of the adsorbent after multiple adsorption-desorption cycles, its regeneration efficiency and long-term application feasibility are assessed.

[0053] [Fe-based aluminum phosphate-based CO2 adsorbent]

[0054] The present invention also provides a Fe-based aluminum phosphate-based CO2 adsorbent, which is prepared by the method described above for preparing Fe-based aluminum phosphate-based CO2 adsorbents.

[0055] The Fe-based aluminum phosphate-based CO2 adsorbent provided by this invention has a CO2 adsorption capacity ≥4.9 mmol / g under conditions of 3–5 bar and 20–30°C. The CO2 adsorption capacity of the Fe-based aluminum phosphate-based CO2 adsorbent under these conditions can be selected as ≥5.0 mmol / g, ≥5.1 mmol / g, ≥5.2 mmol / g, ≥5.3 mmol / g, ≥5.4 mmol / g, ≥5.5 mmol / g, ≥5.6 mmol / g, ≥5.7 mmol / g, ≥5.8 mmol / g, ≥5.9 mmol / g, etc.

[0056] Further optionally, the CO2 adsorbent based on Fe-based aluminum phosphate has a CO2 adsorption capacity ≥5.0 mmol / g under conditions of 4–5 bar and 20–30 °C, which can be selected as ≥5.1 mmol / g, ≥5.2 mmol / g, ≥5.3 mmol / g, ≥5.4 mmol / g, ≥5.5 mmol / g, ≥5.6 mmol / g, ≥5.7 mmol / g, ≥5.8 mmol / g, ≥5.9 mmol / g, etc.

[0057] Preferably, the CO2 adsorbent based on Fe-based aluminum phosphate has a CO2 adsorption capacity of 5.2–5.9 mmol / g at 4 bar and 25°C, for example, 5.8–5.9 mmol / g, 5.7–5.9 mmol / g, 5.6–5.9 mmol / g, 5.5–5.9 mmol / g, 5.4–5.9 mmol / g, or 5.3–5.9 mmol / g.

[0058] The Fe-based aluminum phosphate-based CO2 adsorbent provided by this invention has an adsorption heat of no more than 25 kJ / mol. This adsorption heat is very low in the industry and can effectively reduce the regeneration energy consumption and accelerate the regeneration cycle of the adsorbent in fast pressure swing adsorption (PSA).

[0059] In the Fe-based aluminum phosphate CO2 adsorbent provided by the present invention, the Fe-based aluminum phosphate CO2 adsorbent is spherical.

[0060] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0061] Before further describing specific embodiments of the present invention, it should be understood that the scope of protection of the present invention is not limited to the specific embodiments described below; it should also be understood that the terminology used in the embodiments of the present invention is for describing specific embodiments and not for limiting the scope of protection of the present invention. Test methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions or as recommended by the respective manufacturers.

[0062] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in the present invention, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art. In addition to the specific methods, apparatus, and materials used in the embodiments, based on the knowledge of the prior art possessed by one of ordinary skill in the art and the description of this invention, any prior art methods, apparatus, and materials similar to or equivalent to those described, apparatus, and materials in the embodiments of this invention may be used to implement the present invention.

[0063] Example 1

[0064] A method for preparing a Fe-based aluminum phosphate (Fe-AlPO) high-efficiency CO2 adsorbent, using a hydrothermal synthesis method, is disclosed. The method includes the following steps:

[0065] S1. Pre-treatment: Mix aluminum isopropoxide with deionized water at a weight ratio of 1:1.3 and keep stirring for 3 hours to ensure complete dissolution.

[0066] S2. Reaction: Add phosphoric acid dropwise at a molar ratio (aluminum isopropoxide: phosphoric acid = 1:0.802) and continue stirring for 1 hour to form a homogeneous reaction solution.

[0067] S3. Addition of structure-directing agent: Triethylamine (TEA) as a structure-directing agent is added dropwise in a molar ratio (aluminum isopropoxide: phosphoric acid = 1:0.74) and stirred for 24 hours to form a reaction gel with a pH of 5 to 6.

[0068] S4: Add Fe precursor solution and water to the reaction gel to form a doped system. Precisely adjust the molar ratio of Fe / Al2O3 to 5:100 and the molar ratio of water / Al2O3 to 100:1. The doped system is then transferred to a polytetrafluoroethylene-lined stainless steel autoclave and kept at 160°C for 24 hours to promote the growth of ALPO crystals.

[0069] In the aforementioned steps, doping involves precisely adjusting the molar ratio of Fe / Al2O3 to 5:100 to dope the Fe metal precursor into ALPO in order to optimize its lattice parameters and pore structure and improve its CO2 adsorption performance.

[0070] In the aforementioned steps, crystal morphology control is achieved by precisely adjusting the molar ratio of water / Al₂O₃ to 100:1 to prepare spherical aggregates of Fe-AlPO (e.g., Figure 2 To optimize its pore structure and specific surface area.

[0071] S5. Activation: The synthesized Fe-based aluminum phosphate high-efficiency adsorbent (Fe-AlPO) was activated by two methods: calcination and pyrolysis. Calcination was carried out in air at 450℃ for 2.5 hours to remove the structure-directing agent and fully open the pores. Pyrolysis was performed under a nitrogen atmosphere at 210℃ and 0.35 bar to further optimize the pore structure.

[0072] Results: At 4 bar and 25 °C, spherical 5Fe-AlPO (Fe / Al2O3 molar ratio of 5:100) exhibited the highest CO2 adsorption capacity, reaching 5.8 mmol / g. Furthermore, the CO2 adsorption capacities of spherical 5Fe-AlPO at several different temperatures and pressures were selected, and the results are shown in Table 1.

[0073] Table 1. CO2 adsorption performance of 5Fe-AlPO in Example 1

[0074]

[0075] Example 2

[0076] S1: Mix aluminum isopropoxide with deionized water at a weight ratio of 1:1.3 and keep stirring for 3 hours to ensure complete dissolution.

[0077] S2: Add phosphoric acid dropwise at a molar ratio (aluminum isopropoxide: phosphoric acid = 1:0.802) and continue stirring for 1 hour to form a homogeneous reaction solution.

[0078] S3: Triethylamine (TEA) as a structure directing agent was added dropwise at a molar ratio (aluminum isopropoxide: orthophosphoric acid = 1:0.74) and stirred for 24 hours to form a reactive gel with a pH of 5 to 6.

[0079] S4: Add Fe precursor solution and water to the reaction gel to form a doped system. Precisely adjust the molar ratio of Fe / Al2O3 to 4:100 and the molar ratio of water / Al2O3 to 100:1. The doped system is then transferred to a polytetrafluoroethylene-lined stainless steel autoclave and kept at 160°C for 24 hours to promote the growth of ALPO crystals.

[0080] S5: The synthesized Fe-based aluminum phosphate high-efficiency adsorbent (Fe-AlPO) was activated by two methods: calcination and pyrolysis. Calcination was carried out in air at 450℃ for 2.5 h to remove the structure-directing agent and fully open the pores. Pyrolysis was performed under a nitrogen atmosphere at 210℃ and 0.35 bar to further optimize the pore structure.

[0081] Results: At 4 bar and 25 °C, spherical 4Fe-AlPO (Fe / Al2O3 molar ratio of 4:100) exhibited a high CO2 adsorption capacity of 5.5 mmol / g. Furthermore, the CO2 adsorption capacities of spherical 4Fe-AlPO at several different temperatures and pressures were selected, and the results are shown in Table 2.

[0082] Table 2 CO2 adsorption performance of 4Fe-AlPO in Example 2

[0083]

[0084] Example 3

[0085] S1: Mix aluminum isopropoxide with deionized water at a weight ratio of 1:1.3 and keep stirring for 3 hours to ensure complete dissolution.

[0086] S2: Add phosphoric acid dropwise at a molar ratio (aluminum isopropoxide: phosphoric acid = 1:0.802) and continue stirring for 1 hour to form a homogeneous reaction solution.

[0087] S3: Triethylamine (TEA) as a structure directing agent was added dropwise at a molar ratio (aluminum isopropoxide: orthophosphoric acid = 1:0.74) and stirred for 24 hours to form a reactive gel with a pH of 5 to 6.

[0088] S4: Add Fe precursor solution and water to the reaction gel to form a doped system. Precisely adjust the molar ratio of Fe / Al2O3 to 6.5:100 and the molar ratio of water / Al2O3 to 100:1. The doped system is then transferred to a polytetrafluoroethylene-lined stainless steel autoclave and kept at 160°C for 24 hours to promote the growth of ALPO crystals.

[0089] S5: The synthesized Fe-based aluminum phosphate high-efficiency adsorbent (Fe-AlPO) was activated by two methods: calcination and pyrolysis. Calcination was carried out in air at 450℃ for 2.5 h to remove the structure-directing agent and fully open the pores. Pyrolysis was performed under a nitrogen atmosphere at 210℃ and 0.35 bar to further optimize the pore structure.

[0090] Results: Under conditions of 4 bar and 25 °C, spherical 6.5Fe-AlPO (Fe / Al2O3 molar ratio of 6.5:100) exhibited a high CO2 adsorption capacity, reaching 5.2 mmol / g. Furthermore, the CO2 adsorption capacities of spherical 6.5Fe-AlPO at several different temperatures and pressures were selected, and the results are shown in Table 3.

[0091] Table 3 shows the CO2 adsorption performance of 6.5Fe-AlPO in Example 3.

[0092]

[0093] Example 4

[0094] S1: Mix aluminum isopropoxide with deionized water at a weight ratio of 1:1.3 and keep stirring for 2 hours to ensure complete dissolution.

[0095] S2: Add phosphoric acid dropwise at a molar ratio (aluminum isopropoxide: phosphoric acid = 1:0.802) and continue stirring for 1 hour to form a homogeneous reaction solution.

[0096] S3: Triethylamine (TEA) as a structure directing agent was added dropwise at a molar ratio (aluminum isopropoxide: orthophosphoric acid = 1:0.74) and stirred for 24 hours to form a reactive gel with a pH of 5 to 6.

[0097] S4: Add Fe precursor solution and water to the reaction gel to form a doped system. Precisely adjust the molar ratio of Fe / Al2O3 to 5:100 and the molar ratio of water / Al2O3 to 100:1. The doped system is then transferred to a polytetrafluoroethylene-lined stainless steel autoclave and kept at 160°C for 24 hours to promote the growth of ALPO crystals.

[0098] S5: The synthesized Fe-based aluminum phosphate high-efficiency adsorbent (Fe-AlPO) was activated by two methods: calcination and pyrolysis. Calcination was carried out in air at 450℃ for 2.5 h to remove the structure-directing agent and fully open the pores. Pyrolysis was performed under a nitrogen atmosphere at 210℃ and 0.35 bar to further optimize the pore structure.

[0099] Results: At 4 bar and 25 °C, spherical 5Fe-AlPO (Fe / Al2O3 molar ratio of 5:100) exhibited a high CO2 adsorption capacity of 5.7 mmol / g. Furthermore, the CO2 adsorption capacities of spherical 5Fe-AlPO at several different temperatures and pressures were selected, and the results are shown in Table 4.

[0100] Table 4 shows the CO2 adsorption performance of 5Fe-AlPO in Example 4.

[0101]

[0102] Example 5

[0103] S1: Mix aluminum isopropoxide with deionized water at a weight ratio of 1:1.3 and keep stirring for 4.5 hours to ensure complete dissolution.

[0104] S2: Add phosphoric acid dropwise at a molar ratio (aluminum isopropoxide: phosphoric acid = 1:0.802) and continue stirring for 1 hour to form a homogeneous reaction solution.

[0105] S3: Triethylamine (TEA) as a structure directing agent was added dropwise at a molar ratio (aluminum isopropoxide: orthophosphoric acid = 1:0.74) and stirred for 24 hours to form a reactive gel with a pH of 5 to 6.

[0106] S4: Add Fe precursor solution and water to the reaction gel to form a doped system. Precisely adjust the molar ratio of Fe / Al2O3 to 5:100 and the molar ratio of water / Al2O3 to 100:1. The doped system is then transferred to a polytetrafluoroethylene-lined stainless steel autoclave and kept at 160°C for 24 hours to promote the growth of ALPO crystals.

[0107] S5: The synthesized Fe-based aluminum phosphate high-efficiency adsorbent (Fe-AlPO) was activated by two methods: calcination and pyrolysis. Calcination was carried out in air at 450℃ for 2.5 h to remove the structure-directing agent and fully open the pores. Pyrolysis was performed under a nitrogen atmosphere at 210℃ and 0.35 bar to further optimize the pore structure.

[0108] Results: At 4 bar and 25 °C, spherical 5Fe-AlPO (Fe / Al2O3 molar ratio of 5:100) exhibited a high CO2 adsorption capacity of 5.9 mmol / g. Furthermore, the CO2 adsorption capacities of spherical 5Fe-AlPO at several different temperatures and pressures were selected, and the results are shown in Table 5.

[0109] Table 5 shows the CO2 adsorption performance of 5Fe-AlPO in Example 5.

[0110]

[0111]

[0112] Example 6

[0113] S1: Mix aluminum isopropoxide with deionized water at a weight ratio of 1:1.3 and keep stirring for 3 hours to ensure complete dissolution.

[0114] S2: Add phosphoric acid dropwise at a molar ratio (aluminum isopropoxide: phosphoric acid = 1:0.802) and continue stirring for 0.75 hours to form a homogeneous reaction solution.

[0115] S3: Triethylamine (TEA) as a structure directing agent was added dropwise at a molar ratio (aluminum isopropoxide: orthophosphoric acid = 1:0.74) and stirred for 24 hours to form a reactive gel with a pH of 5 to 6.

[0116] S4: Add Fe precursor solution and water to the reaction gel to form a doped system. Precisely adjust the molar ratio of Fe / Al2O3 to 5:100 and the molar ratio of water / Al2O3 to 100:1. The doped system is then transferred to a polytetrafluoroethylene-lined stainless steel autoclave and kept at 160°C for 24 hours to promote the growth of ALPO crystals.

[0117] S5: The synthesized Fe-based aluminum phosphate high-efficiency adsorbent (Fe-AlPO) was activated by two methods: calcination and pyrolysis. Calcination was carried out in air at 450℃ for 2.5 h to remove the structure-directing agent and fully open the pores. Pyrolysis was performed under a nitrogen atmosphere at 210℃ and 0.35 bar to further optimize the pore structure.

[0118] Results: At 4 bar and 25 °C, spherical 5Fe-AlPO (Fe / Al2O3 molar ratio of 5:100) exhibited a high CO2 adsorption capacity of 5.6 mmol / g. Furthermore, the CO2 adsorption capacities of spherical 5Fe-AlPO at several different temperatures and pressures were selected, and the results are shown in Table 6.

[0119] Table 6 shows the CO2 adsorption performance of 5Fe-AlPO in Example 6.

[0120]

[0121] Example 7

[0122] S1: Mix aluminum isopropoxide with deionized water at a weight ratio of 1:1.3 and keep stirring for 3 hours to ensure complete dissolution.

[0123] S2: Add phosphoric acid dropwise at a molar ratio (aluminum isopropoxide: phosphoric acid = 1:0.802) and continue stirring for 1.75 hours to form a homogeneous reaction solution.

[0124] S3: Triethylamine (TEA) as a structure directing agent was added dropwise at a molar ratio (aluminum isopropoxide: orthophosphoric acid = 1:0.74) and stirred for 24 hours to form a reactive gel with a pH of 5 to 6.

[0125] S4: Add Fe precursor solution and water to the reaction gel to form a doped system. Precisely adjust the molar ratio of Fe / Al2O3 to 5:100 and the molar ratio of water / Al2O3 to 100:1. The doped system is then transferred to a polytetrafluoroethylene-lined stainless steel autoclave and kept at 160°C for 24 hours to promote the growth of ALPO crystals.

[0126] S5: The synthesized Fe-based aluminum phosphate high-efficiency adsorbent (Fe-AlPO) was activated by two methods: calcination and pyrolysis. Calcination was carried out in air at 450℃ for 2.5 h to remove the structure-directing agent and fully open the pores. Pyrolysis was performed under a nitrogen atmosphere at 210℃ and 0.35 bar to further optimize the pore structure.

[0127] Results: At 4 bar and 25 °C, spherical 5Fe-AlPO (Fe / Al2O3 molar ratio of 5:100) exhibited a high CO2 adsorption capacity of 5.6 mmol / g. Furthermore, the CO2 adsorption capacities of spherical 5Fe-AlPO at several different temperatures and pressures were selected, and the results are shown in Table 7.

[0128] Table 7 CO2 adsorption performance of 5Fe-AlPO in Example 7

[0129]

[0130] Example 8

[0131] S1: Mix aluminum isopropoxide with deionized water at a weight ratio of 1:1.3 and keep stirring for 3 hours to ensure complete dissolution.

[0132] S2: Add phosphoric acid dropwise at a molar ratio (aluminum isopropoxide: phosphoric acid = 1:0.802) and continue stirring for 1 hour to form a homogeneous reaction solution.

[0133] S3: Triethylamine (TEA) as a structure directing agent was added dropwise in a molar ratio (aluminum isopropoxide: phosphoric acid = 1:0.74) and stirred for 18 hours to form a reactive gel with a pH of 5 to 6.

[0134] S4: Add Fe precursor solution and water to the reaction gel to form a doped system. Precisely adjust the molar ratio of Fe / Al2O3 to 5:100 and the molar ratio of water / Al2O3 to 100:1. The doped system is then transferred to a polytetrafluoroethylene-lined stainless steel autoclave and kept at 160°C for 24 hours to promote the growth of ALPO crystals.

[0135] S5: The synthesized Fe-based aluminum phosphate high-efficiency adsorbent (Fe-AlPO) was activated by two methods: calcination and pyrolysis. Calcination was carried out in air at 450℃ for 2.5 h to remove the structure-directing agent and fully open the pores. Pyrolysis was performed under a nitrogen atmosphere at 210℃ and 0.35 bar to further optimize the pore structure.

[0136] Results: At 4 bar and 25 °C, spherical 5Fe-AlPO (Fe / Al2O3 molar ratio of 5:100) exhibited a high CO2 adsorption capacity of 5.6 mmol / g. Furthermore, the CO2 adsorption capacities of spherical 5Fe-AlPO at several different temperatures and pressures were selected, and the results are shown in Table 8.

[0137] Table 8 shows the CO2 adsorption performance of 5Fe-AlPO in Example 8.

[0138]

[0139] Example 9

[0140] S1: Mix aluminum isopropoxide with deionized water at a weight ratio of 1:1.3 and keep stirring for 3 hours to ensure complete dissolution.

[0141] S2: Add phosphoric acid dropwise at a molar ratio (aluminum isopropoxide: phosphoric acid = 1:0.802) and continue stirring for 1 hour to form a homogeneous reaction solution.

[0142] S3: Triethylamine (TEA) as a structure directing agent was added dropwise in a molar ratio (aluminum isopropoxide: phosphoric acid = 1:0.74) and stirred for 30 hours to form a reactive gel with a pH of 5 to 6.

[0143] S4: Add Fe precursor solution and water to the reaction gel to form a doped system. Precisely adjust the molar ratio of Fe / Al2O3 to 5:100 and the molar ratio of water / Al2O3 to 100:1. The doped system is then transferred to a polytetrafluoroethylene-lined stainless steel autoclave and kept at 160°C for 24 hours to promote the growth of ALPO crystals.

[0144] S5: The synthesized Fe-based aluminum phosphate high-efficiency adsorbent (Fe-AlPO) was activated by two methods: calcination and pyrolysis. Calcination was carried out in air at 450℃ for 2.5 h to remove the structure-directing agent and fully open the pores. Pyrolysis was performed under a nitrogen atmosphere at 210℃ and 0.35 bar to further optimize the pore structure.

[0145] Results: At 4 bar and 25 °C, spherical 5Fe-AlPO (Fe / Al2O3 molar ratio of 5:100) exhibited a high CO2 adsorption capacity of 5.9 mmol / g. Furthermore, the CO2 adsorption capacities of spherical 5Fe-AlPO at several different temperatures and pressures were selected, and the results are shown in Table 9.

[0146] Table 9 shows the CO2 adsorption performance of 5Fe-AlPO in Example 9.

[0147]

[0148] Example 10

[0149] S1: Mix aluminum isopropoxide with deionized water at a weight ratio of 1:1.3 and keep stirring for 3 hours to ensure complete dissolution.

[0150] S2: Add phosphoric acid dropwise at a molar ratio (aluminum isopropoxide: phosphoric acid = 1:0.802) and continue stirring for 1 hour to form a homogeneous reaction solution.

[0151] S3: Triethylamine (TEA) as a structure directing agent was added dropwise at a molar ratio (aluminum isopropoxide: orthophosphoric acid = 1:0.74) and stirred for 24 hours to form a reactive gel with a pH of 5 to 6.

[0152] S4: Add Fe precursor solution and water to the reaction gel to form a doped system. Precisely adjust the molar ratio of Fe / Al2O3 to 5:100 and the molar ratio of water / Al2O3 to 100:1. The doped system is then transferred to a polytetrafluoroethylene-lined stainless steel autoclave and kept at 160°C for 24 hours to promote the growth of ALPO crystals.

[0153] S5: The synthesized Fe-based aluminum phosphate high-efficiency adsorbent (Fe-AlPO) was activated by both calcination and pyrolysis. Calcination was carried out in air at 450°C for 2.5 hours to remove the structure-directing agent and fully open the pores. Pyrolysis was performed under a nitrogen atmosphere at 200°C and 0.35 bar to further optimize the pore structure.

[0154] Results: At 4 bar and 25 °C, spherical 5Fe-AlPO (Fe / Al2O3 molar ratio of 5:100) exhibited a high CO2 adsorption capacity of 5.8 mmol / g. Furthermore, the CO2 adsorption capacities of spherical 5Fe-AlPO at several different temperatures and pressures were selected, and the results are shown in Table 10.

[0155] Table 10 CO2 adsorption performance of 5Fe-AlPO in Example 10

[0156]

[0157] Example 11

[0158] S1: Mix aluminum isopropoxide with deionized water at a weight ratio of 1:1.3 and keep stirring for 3 hours to ensure complete dissolution.

[0159] S2: Add phosphoric acid dropwise at a molar ratio (aluminum isopropoxide: phosphoric acid = 1:0.802) and continue stirring for 1 hour to form a homogeneous reaction solution.

[0160] S3: Triethylamine (TEA) as a structure directing agent was added dropwise at a molar ratio (aluminum isopropoxide: orthophosphoric acid = 1:0.74) and stirred for 24 hours to form a reactive gel with a pH of 5 to 6.

[0161] S4: Add Fe precursor solution and water to the reaction gel to form a doped system. Precisely adjust the molar ratio of Fe / Al2O3 to 5:100 and the molar ratio of water / Al2O3 to 100:1. The doped system is then transferred to a polytetrafluoroethylene-lined stainless steel autoclave and kept at 160°C for 24 hours to promote the growth of ALPO crystals.

[0162] S5: The synthesized Fe-based aluminum phosphate high-efficiency adsorbent (Fe-AlPO) was activated by both calcination and pyrolysis. Calcination was carried out in air at 450°C for 2.5 hours to remove the structure-directing agent and fully open the pores. Pyrolysis was performed under a nitrogen atmosphere at 475°C and 0.35 bar to further optimize the pore structure.

[0163] Results: At 4 bar and 25 °C, spherical 5Fe-AlPO (Fe / Al2O3 molar ratio of 5:100) exhibited a high CO2 adsorption capacity of 5.4 mmol / g. Furthermore, the CO2 adsorption capacities of spherical 5Fe-AlPO at several different temperatures and pressures were selected, and the results are shown in Table 11.

[0164] Table 11 CO2 adsorption performance of 5Fe-AlPO in Example 11

[0165]

[0166]

[0167] Example 12

[0168] S1: Mix aluminum isopropoxide with deionized water at a weight ratio of 1:1.3 and keep stirring for 3 hours to ensure complete dissolution.

[0169] S2: Add phosphoric acid dropwise at a molar ratio (aluminum isopropoxide: phosphoric acid = 1:0.802) and continue stirring for 1 hour to form a homogeneous reaction solution.

[0170] S3: Triethylamine (TEA) as a structure directing agent was added dropwise at a molar ratio (aluminum isopropoxide: orthophosphoric acid = 1:0.74) and stirred for 24 hours to form a reactive gel with a pH of 5 to 6.

[0171] S4: Add Fe precursor solution and water to the reaction gel to form a doped system. Precisely adjust the molar ratio of Fe / Al2O3 to 5:100 and the molar ratio of water / Al2O3 to 100:1. The doped system is then transferred to a polytetrafluoroethylene-lined stainless steel autoclave and kept at 160°C for 24 hours to promote the growth of ALPO crystals.

[0172] S5: The synthesized Fe-based aluminum phosphate high-efficiency adsorbent (Fe-AlPO) was activated by both calcination and pyrolysis. Calcination was carried out in air at 450℃ for 2.5 h to remove the structure-directing agent and fully open the pores. Pyrolysis was performed under a nitrogen atmosphere at 210℃ and 0.10 bar to further optimize the pore structure.

[0173] Results: At 4 bar and 25 °C, spherical 5Fe-AlPO (Fe / Al2O3 molar ratio of 5:100) exhibited a high CO2 adsorption capacity of 5.5 mmol / g. Furthermore, the CO2 adsorption capacities of spherical 5Fe-AlPO at several different temperatures and pressures were selected, and the results are shown in Table 12.

[0174] Table 12 CO2 adsorption performance of 5Fe-AlPO in Example 12

[0175]

[0176] Example 13

[0177] S1: Mix aluminum isopropoxide with deionized water at a weight ratio of 1:1.3 and keep stirring for 3 hours to ensure complete dissolution.

[0178] S2: Add phosphoric acid dropwise at a molar ratio (aluminum isopropoxide: phosphoric acid = 1:0.802) and continue stirring for 1 hour to form a homogeneous reaction solution.

[0179] S3: Triethylamine (TEA) as a structure directing agent was added dropwise at a molar ratio (aluminum isopropoxide: orthophosphoric acid = 1:0.74) and stirred for 24 hours to form a reactive gel with a pH of 5 to 6.

[0180] S4: Add Fe precursor solution and water to the reaction gel to form a doped system. Precisely adjust the molar ratio of Fe / Al2O3 to 5:100 and the molar ratio of water / Al2O3 to 100:1. The doped system is then transferred to a polytetrafluoroethylene-lined stainless steel autoclave and kept at 160°C for 24 hours to promote the growth of ALPO crystals.

[0181] S5: The synthesized Fe-based aluminum phosphate high-efficiency adsorbent (Fe-AlPO) was activated by both calcination and pyrolysis. Calcination was carried out in air at 450°C for 2.5 hours to remove the structure-directing agent and fully open the pores. Pyrolysis was performed under a nitrogen atmosphere at 210°C and 2.00 bar to further optimize the pore structure.

[0182] Results: At 4 bar and 25 °C, spherical 5Fe-AlPO (Fe / Al2O3 molar ratio of 5:100) exhibited a high CO2 adsorption capacity of 5.7 mmol / g. Furthermore, the CO2 adsorption capacities of spherical 5Fe-AlPO at several different temperatures and pressures were selected, and the results are shown in Table 13.

[0183] Table 13 CO2 adsorption performance of 5Fe-AlPO in Example 13

[0184]

[0185] Example 14

[0186] S1: Mix aluminum isopropoxide with deionized water at a weight ratio of 1:1.3 and keep stirring for 3 hours to ensure complete dissolution.

[0187] S2: Add phosphoric acid dropwise at a molar ratio (aluminum isopropoxide: phosphoric acid = 1:0.802) and continue stirring for 1 hour to form a homogeneous reaction solution.

[0188] S3: Triethylamine (TEA) as a structure directing agent was added dropwise at a molar ratio (aluminum isopropoxide: orthophosphoric acid = 1:0.74) and stirred for 24 hours to form a reactive gel with a pH of 5 to 6.

[0189] S4: Add Fe precursor solution and water to the reaction gel to form a doped system. Precisely adjust the molar ratio of Fe / Al2O3 to 5:100 and the molar ratio of water / Al2O3 to 100:1. The doped system is then transferred to a polytetrafluoroethylene-lined stainless steel autoclave and kept at 160°C for 24 hours to promote the growth of ALPO crystals.

[0190] S5: The synthesized Fe-based aluminum phosphate high-efficiency adsorbent (Fe-AlPO) was activated by two methods: calcination and pyrolysis. Calcination was carried out in air at 125°C for 2.5 hours to remove the structure-directing agent and fully open the pores. Pyrolysis was performed under a nitrogen atmosphere at 210°C and 0.35 bar to further optimize the pore structure.

[0191] Results: At 4 bar and 25 °C, spherical 5Fe-AlPO (Fe / Al2O3 molar ratio of 5:100) exhibited a high CO2 adsorption capacity of 5.3 mmol / g. Furthermore, the CO2 adsorption capacities of spherical 5Fe-AlPO at several different temperatures and pressures were selected, and the results are shown in Table 14.

[0192] Table 14 CO2 adsorption performance of 5Fe-AlPO in Example 14

[0193]

[0194] Example 15

[0195] S1: Mix aluminum isopropoxide with deionized water at a weight ratio of 1:1.3 and keep stirring for 3 hours to ensure complete dissolution.

[0196] S2: Add phosphoric acid dropwise at a molar ratio (aluminum isopropoxide: phosphoric acid = 1:0.802) and continue stirring for 1 hour to form a homogeneous reaction solution.

[0197] S3: Triethylamine (TEA) as a structure directing agent was added dropwise at a molar ratio (aluminum isopropoxide: orthophosphoric acid = 1:0.74) and stirred for 24 hours to form a reactive gel with a pH of 5 to 6.

[0198] S4: Add Fe precursor solution and water to the reaction gel to form a doped system. Precisely adjust the molar ratio of Fe / Al2O3 to 5:100 and the molar ratio of water / Al2O3 to 100:1. The doped system is then transferred to a polytetrafluoroethylene-lined stainless steel autoclave and kept at 160°C for 24 hours to promote the growth of ALPO crystals.

[0199] S5: The synthesized Fe-based aluminum phosphate high-efficiency adsorbent (Fe-AlPO) was activated by two methods: calcination and pyrolysis. Calcination was carried out in air at 525°C for 2.5 hours to remove the structure-directing agent and fully open the pores. Pyrolysis was performed under a nitrogen atmosphere at 210°C and 0.35 bar to further optimize the pore structure.

[0200] Results: At 4 bar and 25 °C, spherical 5Fe-AlPO (Fe / Al2O3 molar ratio of 5:100) exhibited a high CO2 adsorption capacity of 5.9 mmol / g. Furthermore, the CO2 adsorption capacities of spherical 5Fe-AlPO at several different temperatures and pressures were selected, and the results are shown in Table 15.

[0201] Table 15 CO2 adsorption performance of 5Fe-AlPO in Example 15

[0202]

[0203] Example 16

[0204] S1: Mix aluminum isopropoxide with deionized water at a weight ratio of 1:1.3 and keep stirring for 3 hours to ensure complete dissolution.

[0205] S2: Add phosphoric acid dropwise at a molar ratio (aluminum isopropoxide: phosphoric acid = 1:0.802) and continue stirring for 1 hour to form a homogeneous reaction solution.

[0206] S3: Triethylamine (TEA) as a structure directing agent was added dropwise at a molar ratio (aluminum isopropoxide: orthophosphoric acid = 1:0.74) and stirred for 24 hours to form a reactive gel with a pH of 5 to 6.

[0207] S4: Add Fe precursor solution and water to the reaction gel to form a doped system. Precisely adjust the molar ratio of Fe / Al2O3 to 5:100 and the molar ratio of water / Al2O3 to 100:1. The doped system is then transferred to a polytetrafluoroethylene-lined stainless steel autoclave and kept at 160°C for 24 hours to promote the growth of ALPO crystals.

[0208] S5: The synthesized Fe-based aluminum phosphate high-efficiency adsorbent (Fe-AlPO) was activated by two methods: calcination and pyrolysis. Calcination was carried out in air at 125°C for 1.5 hours to remove the structure-directing agent and fully open the pores. Pyrolysis was performed under a nitrogen atmosphere at 210°C and 0.35 bar to further optimize the pore structure.

[0209] Results: At 4 bar and 25 °C, spherical 5Fe-AlPO (Fe / Al2O3 molar ratio of 5:100) exhibited a high CO2 adsorption capacity of 5.4 mmol / g. Furthermore, the CO2 adsorption capacities of spherical 5Fe-AlPO at several different temperatures and pressures were selected, and the results are shown in Table 16.

[0210] Table 16 CO2 adsorption performance of 5Fe-AlPO in Example 16

[0211]

[0212] Example 17

[0213] S1: Mix aluminum isopropoxide with deionized water at a weight ratio of 1:1.3 and keep stirring for 3 hours to ensure complete dissolution.

[0214] S2: Add phosphoric acid dropwise at a molar ratio (aluminum isopropoxide: phosphoric acid = 1:0.802) and continue stirring for 1 hour to form a homogeneous reaction solution.

[0215] S3: Triethylamine (TEA) as a structure directing agent was added dropwise at a molar ratio (aluminum isopropoxide: orthophosphoric acid = 1:0.74) and stirred for 24 hours to form a reactive gel with a pH of 5 to 6.

[0216] S4: Add Fe precursor solution and water to the reaction gel to form a doped system. Precisely adjust the molar ratio of Fe / Al2O3 to 5:100 and the molar ratio of water / Al2O3 to 100:1. The doped system is then transferred to a polytetrafluoroethylene-lined stainless steel autoclave and kept at 160°C for 24 hours to promote the growth of ALPO crystals.

[0217] S5: The synthesized Fe-based aluminum phosphate high-efficiency adsorbent (Fe-AlPO) was activated by two methods: calcination and pyrolysis. Calcination was carried out in air at 125°C for 3.5 hours to remove the structure-directing agent and fully open the pores. Pyrolysis was performed under a nitrogen atmosphere at 210°C and 0.35 bar to further optimize the pore structure.

[0218] Results: At 4 bar and 25 °C, spherical 5Fe-AlPO (Fe / Al2O3 molar ratio of 5:100) exhibited a high CO2 adsorption capacity of 5.5 mmol / g. Furthermore, the CO2 adsorption capacities of spherical 5Fe-AlPO at several different temperatures and pressures were selected, and the results are shown in Table 17.

[0219] Table 17 CO2 adsorption performance of 5Fe-AlPO in Example 17

[0220]

[0221]

[0222] Comparative Example 1

[0223] The difference between this comparative example and Example 1 is that the molar ratio of water / Al2O3 in the synthetic mixture was adjusted to 400:1 to control the 5Fe-AlPO crystals to exhibit a columnar morphology (e.g., ...). Figure 1 ), to optimize the pore characteristics of the adsorbent.

[0224] Results: Under conditions of 4 bar and 25 °C, columnar 5Fe-AlPO (Fe / Al2O3 molar ratio of 5:100) exhibited the highest CO2 adsorption capacity of 3.6 mmol / g. Furthermore, the CO2 adsorption capacities of spherical 5Fe-AlPO at different temperatures and pressures were selected, and the results are shown in Table 18.

[0225] Table 18 shows the CO2 adsorption performance of 5Fe-AlPO in Comparative Example 1.

[0226]

[0227] Referring to Tables 1 and 18, Comparative Example 1 shows a decreased adsorption capacity and a significantly increased heat of adsorption. Example 1, however, satisfies both a high CO2 adsorption capacity and a heat of adsorption below 25 kJ / mol. A heat of adsorption below 25 kJ / mol is very low in the industry, effectively reducing adsorbent regeneration energy consumption and accelerating the regeneration cycle in Fast Pressure Swing Adsorption (PSA). This clearly demonstrates that the spherical structure in Example 1 is superior to the columnar structure in Comparative Example 1.

[0228] Comparative Example 2

[0229] The difference between this comparative example and Example 1 is that the molar ratio of Fe / Al2O3 in the synthetic mixture was adjusted to 3:100 to control the morphology of ALPO crystals and optimize their lattice parameters and pore structure.

[0230] Results: At 4 bar and 25 °C, spherical 3Fe-AlPO (Fe / Al2O3 molar ratio of 3:100) exhibited the highest CO2 adsorption capacity of 3.5 mmol / g. Furthermore, the CO2 adsorption capacities of spherical 3Fe-AlPO at several different temperatures and pressures were selected, and the results are shown in Table 19.

[0231] Table 19 CO2 adsorption performance of 3Fe-AlPO in Comparative Example 3

[0232]

[0233] Combining Tables 1 and 19, Comparative Example 2 shows a decreased adsorption capacity and a significantly increased heat of adsorption. Example 1, however, satisfies both a high CO2 adsorption capacity and a heat of adsorption below 25 kJ / mol. A heat of adsorption below 25 kJ / mol is very low in the industry, effectively reducing adsorbent regeneration energy consumption and accelerating the adsorbent regeneration cycle in Fast Pressure Swing Adsorption (PSA). This clearly demonstrates that the Fe / Al2O3 molar ratio of 5:100 in Example 1 is superior to the Fe / Al2O3 molar ratio of 3:100 in Comparative Example 2.

[0234] Comparative Example 3

[0235] The difference between this comparative example and Example 1 is that the doped metal atom is magnesium.

[0236] Results: At 4 bar and 25 °C, spherical 5Mg-AlPO (Mg / Al2O3 molar ratio of 5:100) exhibited the highest CO2 adsorption capacity of 1.7 mmol / g. Furthermore, the CO2 adsorption capacities of spherical 5Mg-AlPO at several different temperatures and pressures were selected, and the results are shown in Table 20.

[0237] Table 20 shows the CO2 adsorption performance of 5Mg-AlPO in Comparative Example 3.

[0238]

[0239] Combining Tables 1 and 20, Comparative Example 3 shows a decreased adsorption capacity and a significantly increased heat of adsorption. Example 1, however, satisfies both a high CO2 adsorption capacity and a heat of adsorption below 25 kJ / mol. A heat of adsorption below 25 kJ / mol is very low in the industry, effectively reducing adsorbent regeneration energy consumption and accelerating the adsorbent regeneration cycle in Fast Pressure Swing Adsorption (PSA). This clearly demonstrates that using Fe as the doping metal in Example 1 is superior to using Mg as the doping metal in Comparative Example 3.

[0240] Comparative Example 4

[0241] The difference between this comparative example and Example 1 is that the doped metal atom is cobalt.

[0242] Results: At 4 bar and 25 °C, spherical 5Co-AlPO (Co / Al2O3 molar ratio of 5:100) exhibited the highest CO2 adsorption capacity of 2.7 mmol / g. Furthermore, the CO2 adsorption capacities of spherical 5Fe-AlPO at several different temperatures and pressures were selected, and the results are shown in Table 21.

[0243] Table 21 CO2 adsorption performance of 5Co-AlPO in Comparative Example 4

[0244]

[0245] Combining Tables 1 and 21, Comparative Example 4 shows a decrease in adsorption capacity and a significant increase in adsorption heat. Example 1, however, satisfies both a high CO2 adsorption capacity and an adsorption heat below 25 kJ / mol. An adsorption heat below 25 kJ / mol is very low in the industry, effectively reducing adsorbent regeneration energy consumption and accelerating the adsorbent regeneration cycle in Fast Pressure Swing Adsorption (PSA). This clearly demonstrates that using Fe as the doping metal in Example 1 is superior to using Co as the doping metal in Comparative Example 4.

[0246] Comparative Example 5

[0247] The difference between this comparative example and Example 1 is that it is not doped with any metal atoms.

[0248] Results: At 4 bar and 25 °C, spherical AlPO exhibited the highest CO2 adsorption capacity of 0.7 mmol / g. Furthermore, the CO2 adsorption capacities of AlPO at several different temperatures and pressures were selected, and the results are shown in Table 22.

[0249] Table 22 CO2 adsorption performance of AlPO in Example 5

[0250]

[0251] Combining Tables 1 and 22, Comparative Example 5 shows a decreased adsorption capacity and a significantly increased heat of adsorption. Example 1, however, satisfies both a high CO2 adsorption capacity and a heat of adsorption below 25 kJ / mol. A heat of adsorption below 25 kJ / mol is very low in the industry, effectively reducing adsorbent regeneration energy consumption and accelerating the adsorbent regeneration cycle in Fast Pressure Swing Adsorption (PSA). This clearly demonstrates that using Fe as the doped metal in Example 1 is superior to using no doped metal in Comparative Example 5.

[0252] Comparative Example 6

[0253] The difference between this comparative example and Example 1 is that the temperature was set to 600°C and the calcination time was 4 hours during the calcination activation process.

[0254] Results: At 4 bar and 25 °C, spherical 5Fe-AlPO (Fe / Al2O3 molar ratio of 5:100) exhibited the highest CO2 adsorption capacity of 3.7 mmol / g. Furthermore, the CO2 adsorption capacities of spherical 5Fe-AlPO at several different temperatures and pressures were selected, and the results are shown in Table 23.

[0255] Table 23 shows the CO2 adsorption performance of 5Fe-AlPO in Comparative Example 6.

[0256]

[0257] Combining Tables 1 and 23, Comparative Example 6 shows a decrease in adsorption capacity and a significant increase in heat of adsorption. Example 1, however, satisfies both a high CO2 adsorption capacity and a heat of adsorption below 25 kJ / mol. A heat of adsorption below 25 kJ / mol is very low in the industry, effectively reducing adsorbent regeneration energy consumption and accelerating the regeneration cycle in Fast Pressure Swing Adsorption (PSA). This clearly demonstrates that the calcination temperature of 450℃ in Example 1 is superior to the calcination temperature of 600℃ in Comparative Example 6.

[0258] Comparative Example 7

[0259] The difference between this comparative example and Example 1 is that the temperature was set to 550°C and the pressure to 0.5 bar during the pyrolysis activation process.

[0260] Results: At 4 bar and 25 °C, spherical 5Fe-AlPO (Fe / Al2O3 molar ratio of 5:100) exhibited the highest CO2 adsorption capacity of 3.7 mmol / g. Furthermore, the CO2 adsorption capacities of spherical 5Fe-AlPO at several different temperatures and pressures were selected, and the results are shown in Table 24.

[0261] Table 24 shows the CO2 adsorption performance of 5Fe-AlPO in Comparative Example 7.

[0262]

[0263]

[0264] Combining Tables 1 and 24, Comparative Example 7 showed a decrease in adsorption capacity and a significant increase in heat of adsorption. Example 1, however, met both the requirements of high CO2 adsorption capacity and heat of adsorption below 25 kJ / mol. A heat of adsorption below 25 kJ / mol is very low in the industry, effectively reducing adsorbent regeneration energy consumption and accelerating the adsorbent regeneration cycle in Fast Pressure Swing Adsorption (PSA). This clearly demonstrates that the pyrolysis temperature of 210℃ in Example 1 is superior to the pyrolysis temperature of 550℃ in Comparative Example 7.

[0265] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for preparing a CO2 adsorbent based on Fe-based aluminum phosphate, characterized in that, The preparation method includes the following steps: 1) Mix aluminum isopropoxide with water and dissolve it with stirring. Then add phosphoric acid and structure directing agent in sequence to form a reaction gel. 2) Add Fe precursor solution and water to the reaction gel obtained in step 1) to form a doped system; wherein, the aluminum isopropoxide is converted to Al2O3 in terms of the number of aluminum atoms, and the molar ratio of water to Al2O3 is 100-250:

1. 3) The doped system obtained in step 2) is subjected to a hydrothermal reaction in a reactor to obtain Fe-doped ALPO crystals; 4) Further activate the Fe-doped ALPO crystal obtained in step 3) to obtain a CO2 adsorbent based on Fe-based aluminum phosphate; In step 2), the aluminum isopropoxide is converted to Al2O3 based on the number of moles of aluminum atoms, and the Fe precursor solution is converted to Fe based on the number of moles of iron atoms. The molar ratio of Fe to Al2O3 is 4:100 to 6.5:

100. In step 4), the activation includes calcination and pyrolysis. The calcination temperature is 125~525℃ and the calcination time is 1.5~3.5 hours. The pyrolysis is carried out in a nitrogen atmosphere at a temperature of 200~475℃ and a pressure of 0.1~2.0 bar.

2. The method for preparing the Fe-based aluminum phosphate-based CO2 adsorbent as described in claim 1, characterized in that, It also includes one or more of the following features: A1) In step 1), aluminum isopropoxide is mixed with water and stirred for 2 to 4.5 hours; A2) In step 1), the structure directing agent is one or more of triethylamine, tetraethylammonium hydroxide, and cyclohexylamine; A3) In step 1), the molar ratio of aluminum isopropoxide, orthophosphoric acid, and structure-directing agent is 1:0.7~1.1:0.6~1.0; A4) In step 1), the orthophosphoric acid and the structure-directing agent are added dropwise; In step 1) of A5, after adding the orthophosphoric acid, stir for 0.75 to 1.75 hours; A6) In step 1), after adding the structure guiding agent, stir for 18-30 hours; In step 1) of A7), the pH value of the reaction gel is 5 to 6.

3. The method for preparing the Fe-based aluminum phosphate-based CO2 adsorbent as described in claim 1, characterized in that, In step 2), the Fe precursor is selected from iron(III) nitrate nonahydrate.

4. The method for preparing the Fe-based aluminum phosphate-based CO2 adsorbent as described in claim 1, characterized in that, It also includes one or more of the following features: B1) In step 3), the temperature of the hydrothermal reaction is 130~200℃; In step 3) of B2), the hydrothermal reaction time is 20-30 hours.

5. A CO2 adsorbent based on Fe-based aluminum phosphate, prepared by the method for preparing a CO2 adsorbent based on Fe-based aluminum phosphate as described in any one of claims 1 to 4.

6. The CO2 adsorbent based on Fe-based aluminum phosphate as described in claim 5, further comprising several of the following features: C1) The Fe-based aluminum phosphate-based CO2 adsorbent described above has a CO2 adsorption capacity ≥4.9 mmol / g under the conditions of 3~5 bar and 20~30℃; C2) The Fe-based aluminum phosphate-based CO2 adsorbent described above has an adsorption heat of no more than 25 kJ / mol; The CO2 adsorbent based on Fe-based aluminum phosphate described in C3 is spherical.

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