A method for modifying zeolite, modified zeolite and application in carbon dioxide capture

Abstract

The application provides a zeolite modification method, modified zeolite and application in carbon dioxide capture, and the zeolite modification method comprises the following steps: S1, providing zeolite and carrying out dry desorption treatment; S2, placing the zeolite after the desorption treatment in a quartz tube, and the quartz tube is in-situ atmosphere; S3, applying a plasma electric field to the quartz tube containing the zeolite for treatment, and placing the quartz tube containing the zeolite in a discharge device, and the discharge device ionizes the gas in the in-situ atmosphere in the quartz tube. The zeolite modification method of the application is applicable to zeolites with different pore size and particle size, and can effectively improve the adsorption and capture effect of carbon dioxide and the cycle stability.

Description

TECHNICAL FIELD

[0001] The present disclosure belongs to the field of environment, and relates to gas separation, carbon capture, and more particularly to a zeolite modification method, modified zeolite and application in carbon dioxide capture. BACKGROUND

[0002] Carbon dioxide is one of the greenhouse gases causing global warming, and countries around the world are striving to achieve carbon neutrality, i.e. balancing emissions by capturing and storing carbon dioxide. The adsorption method carbon capture technology can capture carbon dioxide from carbon-containing gases such as atmosphere / gas, so as to reduce carbon emissions and reduce the concentration of carbon dioxide in the atmosphere. However, the adsorption method carbon capture technology is challenging because it involves the development of high-efficiency adsorption materials, energy consumption, and economic feasibility, etc.

[0003] Commercial adsorption method carbon capture systems usually use solid organic amine adsorbents, in which amine groups are physically or chemically combined with porous carriers such as activated carbon, molecular sieves, porous nanomaterials and active oxidants. Combining the advantages of large specific surface area, high physical selectivity and high capacity of amine functional groups in porous adsorbents, chemical absorption carbon capture has certain prospects in low carbon dioxide concentration (400-1000 ppm) and humid environment. However, these chemical adsorbents need high temperature (> 100℃) to be regenerated. In the regeneration environment of high temperature or high pressure, external water vapor and accumulation in the adsorption bed will cause the amine functional groups in the chemical adsorbents to fail. Therefore, compared with chemical adsorbents, physical adsorption is more economical and practical for commercial applications.

[0004] Among various physical adsorbents, zeolite is a crystalline silicoaluminate microporous material, which is used commercially for catalysis, adsorption and separation. Moreover, it can be used for carbon dioxide capture in multi-component and high humidity gases. Carbon dioxide is physically adsorbed on zeolite by van der Waals forces and electrostatic forces at low temperature, and the selectivity of zeolite for carbon dioxide capture can be improved by optimizing the porous structure of zeolite. The screening effect generated by the confined channels in zeolite and the cation exchange sites in the channels can adjust the adsorption selectivity of carbon dioxide under different environments. However, the preparation process of zeolite with controllable nanostructure is high in cost and complex in process, and the unstable porous structure is a challenge for carbon dioxide capture applications.

[0005] Compared with the technology of regulating zeolite materials in the preparation process, it is necessary to provide a zeolite modification method to optimize the specific surface area and pore structure, and improve the adsorption performance and selectivity and separation capacity of carbon dioxide. SUMMARY

[0006] To this end, the present application proposes a zeolite modification method, modified zeolite and its application in carbon dioxide capture, which optimizes the specific surface area and pore structure of zeolite, especially commercial aluminum silicate zeolite. Through ion exchange and material modification techniques such as alternating crystal field strength and pH, the zeolite structure can be modified to have excellent performance, so that the modified zeolite has a higher specific surface area and a stable porous structure, thereby providing a higher carbon dioxide adsorption capacity. Further, by limiting the distribution of cations in the zeolite pores, the selective adsorption and separation capacity of the zeolite for carbon dioxide in a carbon dioxide gas mixture can be enhanced within a certain range. The method of the present application is simple, low in cost, environmentally friendly and free of chemical reagent pollution, and is of great significance to the development of carbon capture technology by adsorption method.

[0007] A brief summary of the present disclosure will be given in the following to provide a basic understanding of certain aspects of the present disclosure. It should be understood that this summary is not an exhaustive overview of the present disclosure. It is not intended to identify key or important parts of the present disclosure nor is it intended to limit the scope of the present disclosure. Its purpose is merely to present some concepts in a simplified form as a prelude to a more detailed description to be discussed later.

[0008] According to an aspect of the present disclosure, a zeolite modification method is provided, comprising the following steps:

[0009] S1, providing a zeolite and performing a drying and desorption treatment;

[0010] S2, placing the desorbed zeolite in a quartz tube, and the quartz tube is in an in-situ atmosphere;

[0011] S3, applying an electric field to the quartz tube containing the zeolite for treatment, and placing the quartz tube containing the zeolite in a discharge device, and the discharge device ionizes the gas in the in-situ atmosphere in the quartz tube.

[0012] Further, the zeolite has a pore size of 3-13 angstroms and a particle diameter of 1-5 mm.

[0013] Further, the drying and desorption treatment includes placing the zeolite in a drying box and desorbing at 100-300 DEG C for 1-3 hours.

[0014] Further, the in-situ atmosphere is achieved by introducing high-purity gas with a purity of 99.999% for a period of time to completely replace the air in the tube.

[0015] Further, the in-situ atmosphere is a nitrogen atmosphere or a carbon dioxide atmosphere.

[0016] Further, the electric discharge device comprises a high-voltage electrode, a grounding electrode, an isolation column supported between the high-voltage electrode and the grounding electrode, a dielectric plate arranged between the high-voltage electrode and the grounding electrode, and a plurality of gold-plated needles arranged on opposite surfaces of the dielectric plate.

[0017] Further, the electric field strength during the treatment by applying the electric field is 60-300 kV / m, and the treatment time is 0.5-5 hours.

[0018] Further, the greater the electric field strength during the treatment by applying the electric field, the shorter the treatment time.

[0019] According to another aspect of the present disclosure, a modified zeolite obtained by the zeolite modification method is provided.

[0020] According to still another aspect of the present disclosure, an application of the modified zeolite in carbon dioxide capture is provided.

[0021] The present application has the following advantages:

[0022] 1. The modified zeolite is simple to prepare, low in energy consumption and raw material cost, and free of chemical pollution.

[0023] 2. The modified zeolite can be recycled under high-temperature and hydrothermal conditions, has high cycle stability, good regeneration performance, and is of great significance in practical engineering applications.

[0024] 3. The modified zeolite has significantly improved carbon dioxide adsorption capacity. BRIEF DESCRIPTION OF DRAWINGS

[0025] The specific content of the present disclosure will be described below with reference to the accompanying drawings, which will help to more easily understand the above and other purposes, features and advantages of the present disclosure. The accompanying drawings are only used to illustrate the principles of the present disclosure. In the drawings, the sizes and relative positions of units are not necessarily drawn according to scale.

[0026] Figure 1 The figure is a schematic diagram of the device for the zeolite modification method of the present application.

[0027] Figure 2 The figure is a column chart of the carbon dioxide adsorption and capture effect of the modified zeolite prepared in Example 1, Example 2 and Example 3 of the present application and the zeolite before modification.

[0028] Figure 3 The figure is a carbon dioxide adsorption stability curve of the modified zeolite prepared in Example 3 of the present application after high-temperature treatment at 180℃.

[0029] Figure 4The carbon dioxide adsorption stability curve of the modified zeolite prepared for the third embodiment of the present application during 5 cycles of adsorption at 40 DEG C and desorption at 180 DEG C. DETAILED DESCRIPTION

[0030] The exemplary disclosure of the present disclosure will be described hereinafter with reference to the drawings. In the specification, all the features to implement the present disclosure are not described for the sake of clarity and conciseness. However, it should be appreciated that many disclosure-specific decisions can be made in developing any such implementation of the present disclosure in order to achieve the specific goals of the developer, and these decisions can vary from implementation to implementation of the present disclosure.

[0031] Here, it should also be noted that, in order to avoid obscuring the present disclosure due to unnecessary details, only the device structures closely related to the scheme according to the present disclosure are shown in the drawings, and other details not closely related to the present disclosure are omitted.

[0032] In general, it should be understood that the drawings and the various elements depicted therein are not to scale. In addition, the use of relative terms (e.g., "above," "below," "top," "bottom," "upper" and "lower") to describe the orientation of various elements should be understood to encompass different orientations of the device and / or elements unless otherwise specified herein or otherwise understood from the context of the description of the figure.

[0033] It should be understood that the present disclosure is not limited to the described embodiments merely because of the description made with reference to the drawings. Herein, features between different embodiments can be replaced or borrowed, and one or more features can be omitted in one embodiment, where the same reference numerals represent the same parts. It should be understood that the manufacturing steps of the present disclosure are exemplary in the embodiments, and the order of the steps can be adjusted.

[0034] First Embodiment

[0035] The present application is based on the characteristics of high specific surface area of zeolite, controllable pore structure, surface functionalization, and low energy consumption of regeneration, and uses zeolite as a raw material. The zeolite is modified by ionization of in-situ atmosphere at room temperature through a dielectric barrier discharge device, and the zeolite structure is modified by the ionized active gas molecules and the electric field. The zeolite is modified by the electric field and the active in-situ atmosphere generated by the dielectric barrier discharge device. The active in-situ atmosphere under the action of the electric field enhances the selective adsorption of the zeolite to the gas. The specific surface area and the carbon dioxide adsorption effect of the modified zeolite are compared, and an optimal zeolite modification technology is proposed.

[0036] The first embodiment of the present application provides a zeolite modification method, and the specific steps are as follows:

[0037] The zeolite is weighed and subjected to desorption drying. In Example 1, 100 mg of 3A zeolite (particle diameter 3-5 mm) having a pore size of about 3 A is subjected to desorption drying. Specifically, a commercially available widely used aluminum silicate zeolite can be selected, and subjected to desorption drying in a drying oven at 100-300°C for 1-3 hours, preferably at 200°C for 2 hours.

[0038] The desorbed zeolite is placed in a quartz tube in an in-situ atmosphere, specifically, the in-situ atmosphere is preferably a nitrogen atmosphere, which can be achieved by introducing high-purity nitrogen gas with a purity of 99.999% for 20-60 minutes, preferably 30 minutes, to completely replace the air in the tube. After sealing, a nitrogen atmosphere is achieved in the quartz tube.

[0039] Referring to Figure 1 The quartz tube (1) containing the zeolite and nitrogen is subjected to an electric field treatment. Specifically, the quartz tube containing the zeolite is placed in a discharge device, which includes two electrodes, a high-voltage electrode 2 and a grounded electrode 3, and a dielectric plate 4 as a dielectric material is arranged between the electrodes. The dielectric material is preferably a porous epoxy plate. In order to achieve current transmission in the discharge gap, a strong enough electric field is provided to cause breakdown in the in-situ gas and ionize the in-situ gas, and a dielectric material with low dielectric loss is used to prevent changes in the discharge mode. Further, the discharge device preferably uses nylon as the support column (5) between the electrodes. A plurality of gold-plated needles (6) are arranged on the opposite side of the dielectric plate 4 to block or limit the flow of current and produce extensive gas ionization. Since the gold-plated needles (6) are located on the side of the high-voltage electrode 2, opposite the dielectric plate 4, the current flowing from the gold-plated needles (6) is limited due to the presence of the dielectric plate 4, thus producing ionization. During treatment, an electric field strength of 60 kV / m-300 kV / m is set, and the treatment time is 0.5-5 hours. The higher the field strength, the shorter the treatment time. The electric field strength is preferably 110 kV / m, and the treatment time is 3 hours.

[0040] ​The microporous material pores in the zeolite can be actively adjusted by electric field treatment for adsorption of the material. After the electric field is added, the adsorption energy of the carbon dioxide molecules in the zeolite cage structure is reduced. The adsorption energy decreases with the increase of the electric field strength, but the decreasing trend slows down. After the electric field is added, the number of charges transferred between the carbon dioxide molecules and the cage structure is reduced. That is, the interaction between them is weakened. This shows that the applied electric field can be used as an effective means for carbon dioxide desorption. The cation distribution and the skeleton expansion of the zeolite can be adjusted by applying an electric field. The electric field formed by the dielectric barrier discharge can ionize the in-situ gas to produce active molecules. The electric field makes the zeolite transform into a stable low-energy structure. Through ion exchange and field strength control, the active in-situ molecules can adjust the low-energy zeolite structure so that it can accommodate more carbon dioxide. By increasing the specific surface area and the adsorption sites for carbon dioxide, the gas adsorption and separation performance can be improved by optimizing the distribution of the adsorption sites. The method is simple, cheap, and has no toxic side effects, which is of great significance to the carbon capture technology by adsorption method.

[0041] The modified zeolite obtained in this example is encapsulated for standby use. The modified zeolite prepared in this example is used in a laboratory condition, and a thermogravimetric analyzer and a temperature programmed simulation are used, as shown in Figure 2 , carbon dioxide adsorption is carried out in a standard gas mixture of 5000ppm carbon dioxide / nitrogen atmosphere, so that the carbon dioxide adsorption capacity of the modified zeolite is increased from the original 4.2mmol·g -1 to 5.1mmol·g -1 . The specific surface area of the modified zeolite is also increased from the original 596.24m 2 ·g -1 to 629.7m 2 ·g -1 . Figure 2 It is shown that the carbon dioxide adsorption capacity of the modified zeolite of the present application is significantly improved.

[0042] Second embodiment

[0043] The main difference between this embodiment and the first embodiment is that the 3A zeolite (particle size 3-5mm) with a pore size of about is replaced by 5A zeolite (particle size 3-5mm) with a pore size of about , and the specific steps are as follows:

[0044] The 5A zeolite (particle size 3-5mm) is dried and desorbed, specifically, 100mg of aluminum silicate zeolite is taken and placed in a drying oven for desorption at 200℃ for 2 hours;

[0045] The desorbed zeolite is placed in a quartz tube with an in-situ atmosphere, specifically, the in-situ atmosphere is preferably a nitrogen atmosphere, which can be achieved by introducing high-purity nitrogen with a purity of 99.999% for 30 minutes to completely replace the air in the tube, thereby achieving a nitrogen atmosphere in the quartz tube;

[0046] The quartz tube with the zeolite is subjected to an electric field for treatment, specifically, the quartz tube with the zeolite is placed in a discharge device, which is the same as that of Example 1, and an electric field strength of 110 kV / m is set, and the treatment time is 3 hours.

[0047] The material prepared in this example is tested under laboratory conditions using a thermogravimetric analyzer and a temperature programmed simulation, as described in Figure 2 , and a standard gas mixture of 1000 ppm carbon dioxide / nitrogen atmosphere is used for carbon dioxide adsorption, so that the carbon dioxide adsorption capacity of the zeolite is increased from the original 4.5 mmol·g -1 to 5.4 mmol·g -1 . 2 ·g -1 2 ·g -1 . Figure 2 It is shown that the carbon dioxide adsorption capacity of the modified zeolite of the present application is significantly improved.

[0048] Third embodiment

[0049] The main difference between this embodiment and the first embodiment is that the 3A zeolite with a pore size of about mm) is replaced by 13X zeolite with a pore size of about mm) and the nitrogen atmosphere is replaced by a carbon dioxide atmosphere, and the specific steps are as follows:

[0050] The 13X zeolite (particle diameter 1-2 mm) is desorbed and dried, specifically, 100 mg of aluminum silicate zeolite is taken and placed in a drying oven for desorption at 200°C for 2 hours;

[0051] The desorbed zeolite is placed in a quartz tube with an in-situ atmosphere, specifically, the in-situ atmosphere is preferably a carbon dioxide atmosphere, which can be achieved by introducing high-purity carbon dioxide with a purity of 99.999% for 30 minutes to completely replace the air in the tube, thereby achieving a carbon dioxide atmosphere in the quartz tube;

[0052] The quartz tube with the zeolite is subjected to an electric field for treatment, specifically, the quartz tube with the zeolite is placed in a discharge device, which is the same as that of Example 1, and an electric field strength of 220 kV / m is set, and the treatment time is 1 hour.

[0053] ​The material prepared in the embodiment is used in laboratory conditions by using a thermal gravimetric analyzer and a programmed temperature simulation, see Figure 2 The carbon dioxide adsorption is carried out in a standard gas mixture 400 ppm carbon dioxide / nitrogen atmosphere, so that the carbon dioxide adsorption capacity of the modified zeolite is increased from the original 4.76 mmol·g -1 to 5.59 mmol·g -1 The specific surface area is also increased from the original 596.24 m 2 ·g -1 to 733.44 m 2 ·g -1 . Figure 2 It is shown that the carbon dioxide adsorption capacity of the modified zeolite of the present application is significantly increased.

[0054] The carbon dioxide adsorption material prepared in the present application is a solid spherical zeolite particle, and has a very good adsorption and capture effect on carbon dioxide in carbon dioxide flue gas with a concentration of 400-5000 ppm. According to the 13X zeolite prepared in Example 3, it can be recycled under high temperature (see Figure 3 ) and hydrothermal environment (see Figure 4 ), and Figure 3 It is shown that the modified zeolite of the present application has very good high-temperature stability under a long-term operating environment of 180℃. Figure 4 It is shown that the modified zeolite of the present application has very good hydrothermal stability under a multiple adsorption / desorption cycle operating environment. After being treated with water vapor at 180℃ for 20 hours, the adsorption capacity for 400 ppm carbon dioxide is only decreased by 0.496%. After 5 consecutive adsorption operations in a 400 ppm carbon dioxide and 40℃ environment and desorption operations in a nitrogen and 180℃ environment, the adsorption capacity is only decreased by 0.27%. This shows that the modified zeolite can be applied in direct air carbon capture (400 ppm), carbon dioxide capture and separation before combustion (500-5000 ppm), and has a wide application value in carbon capture.

[0055] It can be seen that the zeolite modification method of the present application is applicable to zeolites with different pore sizes and particle sizes, and effectively improves the carbon dioxide adsorption and capture effect and the cycle stability.

[0056] Fourth embodiment

[0057] The fourth embodiment of the present application provides a modified zeolite prepared by the zeolite modification method of the present application.

[0058] Fifth embodiment

[0059] The fifth embodiment of the present application provides an application of the modified zeolite of the present application in carbon dioxide capture.

[0060] The present disclosure is described above with reference to specific embodiments. As one skilled in the art will readily appreciate, the description is illustrative of the present disclosure and not restrictive thereof. Various modifications can be made to the present disclosure by those skilled in the art without departing from the spirit and scope of the present disclosure, and it is intended that such modifications are to be included within the scope of the present disclosure.

Claims

1. A method for modifying a zeolite, characterized by, The method comprises the following steps: S1, providing zeolite and performing desorption treatment; S2, placing the desorbed zeolite in a quartz tube, and the quartz tube is in an in-situ atmosphere, wherein the in-situ atmosphere is a nitrogen atmosphere or a carbon dioxide atmosphere; S3, applying an electric field to the quartz tube containing the zeolite to perform treatment, and placing the quartz tube containing the zeolite in a discharge device, wherein the discharge device ionizes the gas in the in-situ atmosphere in the quartz tube, and the electric field strength during the treatment is 60-300 kV / m, and the treatment time is 0.5-5 hours.

2. The method of claim 1, wherein: The zeolite has a pore size of 3-13 angstroms and a particle diameter of 1-5 mm.

3. The method of claim 1, wherein: The desorption treatment comprises placing the zeolite in a drying box and desorbing at 100-300°C for 1-3 hours.

4. The method of claim 1, wherein: The in-situ atmosphere is achieved by introducing high-purity gas with a purity of 99.999% into the quartz tube for a period of time to completely replace the air in the tube.

5. The method of claim 1, wherein: The discharge device comprises a high-voltage electrode, a grounding electrode, a support column between the high-voltage electrode and the grounding electrode, a dielectric plate arranged between the high-voltage electrode and the grounding electrode, and a plurality of gold-plated needles arranged on the opposite side of the dielectric plate.

6. The method of claim 1, wherein: The greater the electric field strength, the shorter the treatment time.

7. A modified zeolite obtained by the method for modifying zeolite according to any one of claims 1-6.

8. Use of the modified zeolite of claim 7 in carbon dioxide capture.

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