An akali-activated solid adsorbent material and its preparation method and application

Abstract

The present invention provides a red mud-based solid adsorption material, a preparation method and an application thereof, relating to the technical field of gas adsorbents. The red mud-based solid adsorption material comprises an adsorption matrix formed by calcining and modifying red mud, coal gangue and biomass, and a zinc-coordinated imidazole organic framework layer is formed on the surface of the adsorption matrix; and polyethyleneimine is attached between the voids of the adsorption matrix and the zinc-coordinated imidazole organic framework layer. The red mud-based solid adsorption material of the present invention improves the adsorption capacity for CO 2 by coupling chemical adsorption and physical adsorption, and simultaneously realizes the mineralization of CO 2 .

Description

Technical Field

[0001] The present invention relates to the technical field of gas adsorbents, and particularly to a red mud-based solid adsorption material, a preparation method thereof, and an application thereof. Background Art

[0002] At present, the fixed-source CO 2 capture technology mainly adopts a centralized capture method in fixed sources such as power plants, including pre-combustion capture, oxy-fuel combustion capture, and post-combustion capture. To reduce CO in the atmosphere 2 and accelerate the realization of the "dual carbon" goal, the development of direct air capture technology (DAC) is essential. And the DAC technology is one of the important technologies that can achieve CO 2 negative emissions, and can control the CO in the atmosphere 2 concentration. Different from traditional centralized capture technologies, the DAC technology can capture CO anytime and anywhere, and directly connect to CO 2 geological sequestration projects. The adsorbent determines the design, adsorption capacity, and application scenarios of the adsorption system, and is the key to CO 2 adsorption.

[0003] At present, various CO 2 solid adsorbents have been developed, such as calcium-based adsorbents, lithium-based adsorbents, porous physical adsorbents, and solid amine adsorbents, which are considered to be promising CO 2 separation technologies. For the application of CO 2 solid adsorbents, the adsorption material is required to have high adsorption / desorption performance, high CO 2 selectivity, chemical / physical stability, low regeneration energy consumption, etc.

[0004] However, the above-mentioned CO 2 solid adsorbents developed have more or less defects: (1) Calcium-based adsorbents are prone to sintering and agglomeration at high temperatures, resulting in a decrease in pore volume and specific surface area, and the generated calcium carbonate covers the surface of the adsorbent, resulting in CO 2 diffusion hindrance and a decrease in adsorption capacity. (2) Lithium-based adsorbents have a relatively high synthesis temperature, high energy consumption, and high cost. Carbon-based adsorbents such as activated carbon and activated carbon fibers show poor CO 2 adsorption capacity and selectivity at low CO 2 partial pressure in flue gas. (3) Porous physical adsorbents (such as porous carbon, activated carbon, zeolite, etc.), porous carbon is generally produced by high-temperature pyrolysis, and an activation process needs to be added during the preparation of activated carbon. At low CO 2 partial pressure, the capacity and selectivity of activated carbon are lower than those of zeolite; however, humidity and high temperature can significantly reduce the CO of zeolite2 Capture performance. (4) Solid amine adsorbent: Generally, amines are loaded into a supporting porous matrix material through physical action. The impregnation method can fill the pores with amine chemical adsorbents and form many carbon dioxide adsorption active centers. However, in the existing solid amine adsorbents, the amine is prone to agglomeration in the matrix material, causing pore blockage and small pore diameter. If small molecular weight amines are filled, the adsorption capacity of the adsorbent will decrease. If high molecular weight polyamine compounds are filled, it is easy to block the mesopores, resulting in a serious decline in the adsorption capacity.

[0005] In view of this, the present invention is specifically proposed. Summary of the Invention

[0006] One of the purposes of the present invention is to provide a red mud-based solid adsorbent material. The red mud-based solid adsorbent material of the present invention has a high-activity adsorption matrix as the core, and the core has a multi-level pore structure; a high-activity zinc-coordinated imidazole organic framework layer shell is formed to form a porous nano-layer to form CO 2 Fast adsorption channels; and polyethyleneimine is attached between the voids of the adsorption matrix and the zinc-coordinated imidazole organic framework layer, so that the solid amine adsorbent prepared by the present invention has a high adsorption capacity, high selectivity and high stability, and can simultaneously achieve the mineralization of CO 2 of.

[0007] Another purpose of the present invention is to provide a preparation method of the red mud-based solid adsorbent material.

[0008] Another purpose of the present invention is to provide an application of the red mud-based solid adsorbent material or the red mud-based solid adsorbent material prepared by the preparation method as a carbon dioxide adsorbent.

[0009] Another purpose of the present invention is to provide a method for adsorbing carbon dioxide. The method for adsorbing carbon dioxide includes the following steps: contacting a gas containing carbon dioxide with the red mud-based solid adsorbent material or the red mud-based solid adsorbent material prepared by the preparation method, and performing an adsorption reaction to achieve the mineralization of carbon dioxide.

[0010] In order to achieve the above purposes of the present invention, the following technical solutions are specifically adopted:

[0011] In the first aspect, the present invention provides a red mud-based solid adsorbent material, which includes an adsorption matrix formed by calcining and modifying red mud, coal gangue and biomass. The surface of the adsorption matrix has a zinc-coordinated imidazole organic framework layer; and polyethyleneimine is attached between the voids of the adsorption matrix and the zinc-coordinated imidazole organic framework layer.

[0012] Among them, red mud is a strongly alkaline solid waste residue generated in the alumina production process, containing various metal oxides, of which 30-60% is Fe2 O 3 also contains components such as CaO. The active solid substances in red mud react with CO 2 to form crystals of CaCO 3 , realizing the capture and mineralization of CO 2 by red mud. The morphology of red mud is irregular, and the pore structure inside the particles is mainly macroporous structure, and the network structure is relatively developed.

[0013] Among them, the main chemical components of coal gangue mainly include SiO 2 , Al 2 O 3 etc. It itself has a large specific surface area and a large porosity, has a high strength and a certain loss on ignition rate, and can generate gas when the material is at high temperature. Therefore, mesopores and micropores can be formed after high-temperature activation, which is beneficial to increasing the porosity of the adsorbent and improving the absorption efficiency.

[0014] Among them, biomass contains components such as plant cellulose and lignin, and the alkali metals or alkaline earth metal components such as calcium (Ca), magnesium (Mg), and potassium (K) contained in itself have a relatively developed pore structure. This structure makes the biological clock very suitable as an adsorption matrix with stable performance and a large specific surface area.

[0015] In the present invention, the adsorption matrix is formed by calcining red mud, coal gangue and biomass, and then carrying out a modification reaction with CaO. The reasons are as follows: First, choosing to co-calcine red mud, coal gangue and biomass, the three cooperate with each other, and a hierarchical pore structure of macropores - mesopores - micropores is formed after synergistic compounding, thereby further improving the physical adsorption capacity of the adsorbent. Second, choosing red mud, coal gangue and biomass, the mixture of the three has a high content of active CaO, SiO 2 , Al 2 O 3 and other components. The synergistic effect of different components after compounding increases the chemical adsorption sites. Third, during the adsorption process, more mineralization reactions will occur to fix more CO 2 and improve the degree of mineralization.

[0016] Secondly, the present invention modifies the calcined products of red mud, coal gangue and biomass, that is, making the calcined products react with CaO to generate gel substances such as calcium silicate hydrate, further improving the activity of the adsorbent and the ability to absorb CO 2 .

[0017] Secondly, it is formed by the chelation of zinc ions and imidazole anions, and has a large specific surface area, high porosity and excellent thermal stability. Therefore, the present invention has a zinc-coordinated imidazole organic framework layer on the surface of the adsorption matrix, and further improves the CO adsorption performance of the adsorbent by rapidly forming a porous nano-layer channel. 2 Adsorption performance.

[0018] Finally, polyethyleneimine is attached to the voids between the adsorption matrix and the zinc-coordinated imidazole organic framework layer. The surface of the polyethyleneimine solid material has a large number of nitrogen-containing groups, and these functional groups will form certain voids and pores at the microscopic level, and can be used to combine with acidic carbon dioxide gas through the action of nitrogen-containing groups to form salts, further improving the adsorption capacity.

[0019] Preferably, the specific surface area of the red mud-based solid adsorbent is 800 m 2 / g or more, for example, it can be 800m 2 / g, 820 m 2 / g, 840 m 2 / g, 860 m 2 / g, 880 m 2 / g, 900 m 2 / g, 920 m 2 / g, 940 m 2 / g, 960 m 2 / g, 980m 2 / g, 1000 m 2 / g, 1010 m 2 / g, 1020 m 2 / g, 1030 m 2 / g, 1040 m 2 / g, 1050 m 2 / g, 1060 m 2 / g, 1070m 2 / g, 1080 m 2 / g, 1090 m 2 / g, 1100 m 2 / g, 1110 m 2 / g, 1120 m 2 / g, 1130 m 2 / g, 1140 m 2 / g, 1150m 2 / g, etc., preferably 1050 m 2 / g or more, more preferably 1050-1150 m 2 / g, etc.

[0020] Preferably, the pore volume of the red mud-based solid adsorbent material is 0.3 cm 3 / g or more, for example, it can be 0.3 cm 3 / g, 0.32 cm 3 / g, 0.34 cm 3 / g, 0.36 cm 3 / g, 0.38 cm 3 / g, 0.4 cm 3 / g, 0.41 cm 3 / g, 0.42 cm 3 / g, 0.43 cm 3 / g, 0.44 cm 3 / g, 0.45 cm 3 / g, 0.46 cm 3 / g, 0.47 cm 3 / g, 0.48 cm 3 / g, 0.49 cm 3 / g, 0.5 cm 3 / g, etc., preferably 0.4 cm 3 / g or more, more preferably 0.4 - 0.5 cm 3 / g.

[0021] Preferably, the pore diameter of the red mud-based solid adsorbent material is 2.4 nm or less, for example, it can be 2.4 nm, 2.3 nm, 2.2 nm, 2.1 nm, 2.0 nm, 1.9 nm, 1.87 nm, 1.85 nm, 1.82 nm, 1.8 nm, 1.78 nm, 1.76 nm, 1.74 nm, 1.72 nm, 1.7 nm, 1.68 nm, 1.66 nm, 1.64 nm, 1.62 nm, 1.6 nm, 1.55 nm, 1.5 nm, 1.4 nm, etc., preferably 1.9 nm or less, more preferably 1.6 - 1.9 nm.

[0022] Preferably, the mass ratio of the red mud, coal gangue, and biomass is 1.0:(0.4 - 1.0):(0.1 - 0.3);

[0023] Among them, "0.4 - 1.0" can be, for example, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, etc.;

[0024] Among them, "0.1 - 0.3" can be, for example, 0.1, 0.12, 0.15, 0.18, 0.2, 0.22, 0.24, 0.25, 0.3, etc.

[0025] Preferably, the biomass is selected from any one or a combination of at least two of straw, peanut shells, corncobs, walnut shells or bamboo.

[0026] In a second aspect, the present invention provides a method for preparing the red mud-based solid adsorbent material as described in the first aspect. The preparation method specifically includes the following steps:

[0027] (1) Mix red mud, coal gangue and biomass, and then conduct the first calcination to obtain a precursor of the adsorption matrix;

[0028] (2) Place the precursor of the adsorption matrix and calcium oxide in a polyethylene glycol solution. After stirring and reacting, collect the product and then conduct the second calcination to obtain the adsorption matrix;

[0029] (3) Place the adsorption matrix in a solution containing a zinc salt and an imidazole compound and stir, and then conduct a microwave heating reaction in sequence to make a zinc-coordinated imidazole organic framework layer adhere to the surface of the adsorption matrix, obtaining a preliminary product of the red mud-based solid adsorbent material;

[0030] (4) Immerse the preliminary product in the solution of polyethyleneimine, and then take out the product for ultrasonic drying treatment, so that polyethyleneimine adheres to the gaps between the adsorption matrix and the zinc-coordinated imidazole organic framework layer, obtaining the red mud-based solid adsorbent material.

[0031] In the above preparation method, in step (1), red mud, coal gangue and biomass are proportioned and calcined together, synergistically forming an ideal multi-level pore structure and enriching active sites, promoting the synergistic effect of physical adsorption and chemical adsorption, thereby significantly improving the CO 2 adsorption capacity and mineralization degree.

[0032] In the above preparation method, in step (2), the precursor of the adsorption matrix and calcium oxide are placed in a polyethylene glycol solution for reaction. After polyethylene glycol melts, it occupies a part of the volume space, displaces the surrounding particles, and leaves a mesoporous structure when cooled, forming a multi-level pore with the original micropores, significantly increasing the specific surface area and pore volume of the material, which is beneficial to the rapid mass transfer and diffusion of CO 2 molecules.

[0033] In the above preparation method, in step (3), a zinc-coordinated imidazole organic framework layer is present on the surface of the adsorption matrix, and a porous nano-layer channel is rapidly formed on the surface of the adsorption matrix through microwave heating of polyol reaction. CO 2 is rapidly adsorbed through the porous nano-layer, and then further diffuses to the inside to react with highly active SiO 2 , Al 2 O 3 and CaO and other components for calcium silicate reaction mineralization, avoiding the blocking of CO due to the mineralization layer after surface mineralization2 Further reaction is carried out to increase its attachment performance.

[0034] In the above preparation method, in step (4), after the initial product is impregnated in the solution of polyethyleneimine, ultrasonic drying treatment is carried out, so that polyethyleneimine is better distributed in the voids between the adsorption matrix and the zinc-coordinated imidazole organic framework layer, so as to further improve the CO 2 adsorption capacity and adsorption rate.

[0035] Preferably, in step (1), pretreatment is required before mixing:

[0036] The red mud is dried at 60-110 °C (for example, it can be 60 °C, 70 °C, 80 °C, 90 °C, 100 °C, 110 °C, etc.) for 1-3 h to obtain red mud with a water content of 5-20 wt% (for example, it can be 5 wt%, 6 wt%, 8 wt%, 10 wt%, 12 wt%, 14 wt%, 16 wt%, 18 wt%, 20 wt%, etc.).

[0037] The coal gangue is crushed to a particle size of less than 0.5 mm, for example, it can be 0.5 mm, 0.4 mm, 0.3 mm, 0.2 mm, 0.1 mm, 0.05 mm, 0.01 mm, etc., to obtain coal gangue powder.

[0038] The biomass is crushed to a particle size of less than 2 mm, for example, it can be 2 mm, 1.8 mm, 1.6 mm, 1.5 mm, 1.4 mm, 1.2 mm, 1 mm, 0.8 mm, 0.6 mm, 0.4 mm, 0.2 mm, 0.1 mm, etc., to obtain biomass powder.

[0039] Preferably, in step (1), the rotation speed of the mixing is 40-120 r / min, for example, it can be 40 r / min, 50 r / min, 60 r / min, 70 r / min, 80 r / min, 90 r / min, 100 r / min, 110 r / min, 120 r / min, etc., and the mixing time is 20-40 min, for example, it can be 20 min, 22 min, 24 min, 26 min, 28 min, 30 min, 32 min, 34 min, 36 min, 38 min, 40 min, etc.

[0040] Preferably, in step (1), the temperature of the first calcination is 400-800 °C, such as 400 °C, 450 °C, 500 °C, 550 °C, 600 °C, 650 °C, 700 °C, 750 °C, 800 °C, etc., and the time of the first calcination is 1.5-2 h, such as 1.5 h, 1.6 h, 1.7 h, 1.8 h, 1.9 h, 2 h, etc.

[0041] Preferably, in step (2), the mass ratio of the precursor of the adsorption matrix to calcium oxide is 1:(0.1-0.3), such as 1:0.1, 1:0.12, 1:0.14, 1:0.16, 1:0.18, 1:0.2, 1:0.22, 1:0.24, 1:0.26, 1:0.28, 1:0.30, etc.

[0042] Preferably, in step (2), the polyethylene glycol solution is an aqueous solution of PEG-400 with a concentration of 5-15 wt% (such as 5 wt%, 6 wt%, 8 wt%, 10 wt%, 12 wt%, 14 wt%, 15 wt%, etc.).

[0043] Preferably, in step (2), the temperature of the stirring reaction is 10-40 °C, such as 10 °C, 12 °C, 14 °C, 16 °C, 18 °C, 20 °C, 22 °C, 24 °C, 26 °C, 28 °C, 30 °C, 32 °C, 34 °C, 36 °C, 38 °C, 40 °C, etc., and the time of the stirring reaction is 2-6 h, such as 2 h, 2.5 h, 3 h, 3.5 h, 4 h, 4.5 h, 5 h, 5.5 h, 6 h, etc.

[0044] Preferably, in step (2), the specific operation of collecting the product is as follows: first, perform suction filtration and / or centrifugation to collect the solid, and then dry the solid at 100-110 °C (such as 100 °C, 102 °C, 104 °C, 106 °C, 108 °C, 110 °C, etc.) for 10-15 h, such as 10 h, 10.5 h, 11 h, 11.5 h, 12 h, 12.5 h, 13 h, 13.5 h, 14 h, 14.5 h, 15 h, etc.

[0045] Preferably, in step (2), the temperature of the second calcination is 700-850 °C, such as 700 °C, 720 °C, 740 °C, 760 °C, 780 °C, 800 °C, 820 °C, 840 °C, 850 °C, etc., and the time of the second calcination is 1-3 h, such as 1 h, 1.2 h, 1.5 h, 1.8 h, 2 h, 2.2 h, 2.5 h, 2.8 h, 3 h, etc.

[0046] Preferably, in step (2), after the second calcination, a pulverizing step is further included, and the adsorbent matrix is pulverized to a particle size of 200-500 μm, for example, it can be 200 μm, 250 μm, 300 μm, 350 μm, 400 μm, 450 μm, 500 μm, etc.

[0047] Preferably, in step (3), the zinc salt is zinc nitrate; the imidazole compound is 2-methylimidazole; the solvent of the solution is ethylene glycol.

[0048] Preferably, in step (3), the solution containing the zinc salt and the imidazole compound comprises, by weight: 5-15 parts of zinc salt, 20-30 parts of imidazole compound, and 80-120 parts of solvent.

[0049] In the solution containing the zinc salt and the imidazole compound, the addition amount of the zinc salt is 5-15 parts, for example, it can be 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, etc., and preferably 8-12 parts.

[0050] In the solution containing the zinc salt and the imidazole compound, the addition amount of the imidazole compound is 20-30 parts, for example, it can be 20 parts, 21 parts, 22 parts, 23 parts, 24 parts, 25 parts, 26 parts, 27 parts, 28 parts, 29 parts, 30 parts, etc., and preferably 21-26 parts.

[0051] In the solution containing the zinc salt and the imidazole compound, the addition amount of the solvent is 80-120 parts, for example, it can be 80 parts, 85 parts, 90 parts, 92 parts, 95 parts, 98 parts, 100 parts, 102 parts, 105 parts, 110 parts, 115 parts, 120 parts, etc.

[0052] Preferably, in step (3), the rotation speed of the stirring is 500-1000 r / min, for example, it can be 500 r / min, 600 r / min, 700 r / min, 800 r / min, 900 r / min, 1000 r / min, etc., and the stirring time is 30-60 min, for example, it can be 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 60 min, etc.

[0053] Preferably, in step (3), the microwave power of the microwave heating reaction is 200 - 400 W, such as 200 W, 250 W, 300 W, 350 W, 400 W, etc.; the temperature of the microwave heating reaction is 120 - 180 °C, such as 120 °C, 125 °C, 130 °C, 135 °C, 140 °C, 145 °C, 150 °C, 155 °C, 160 °C, 165 °C, 170 °C, 175 °C, 180 °C, etc.; and the time of the microwave heating reaction is 5 - 15 min, such as 5 min, 6 min, 8 min, 10 min, 12 min, 15 min, etc.

[0054] Preferably, in step (3), after the microwave heating reaction, there is also a post-treatment step: naturally cooling to room temperature and standing at room temperature for 12 - 24 h, such as 12 h, 14 h, 16 h, 18 h, 20 h, 22 h, 24 h, etc., filtering to obtain crystals; then washing with an ethylene glycol solution and drying to obtain a preliminary product of the red mud-based solid adsorbent.

[0055] Preferably, in step (4), the material ratio of the preliminary product to the solution of polyethyleneimine is 1:(5 - 10), such as 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, etc.

[0056] Preferably, in step (4), the molecular weight of the polyethyleneimine is 10000 - 30000, such as 10000, 12000, 14000, 16000, 18000, 20000, 22000, 24000, 26000, 28000, 30000, etc.

[0057] Preferably, in step (4), the solution of polyethyleneimine is a 5 - 10 wt% (such as 5 wt%, 5.5 wt%, 6 wt%, 6.5 wt%, 7 wt%, 7.5 wt%, 8 wt%, 8.5 wt%, 9 wt%, 9.5 wt%, 10 wt%, etc.) methanol solution of polyethyleneimine.

[0058] Preferably, in step (4), the temperature of the impregnation is 30 - 60 °C, such as 30 °C, 35 °C, 40 °C, 45 °C, 50 °C, 55 °C, 60 °C, etc.; and the time of the impregnation is 1 - 1.5 h, such as 1 h, 1.1 h, 1.2 h, 1.3 h, 1.4 h, 1.5 h, etc.

[0059] Preferably, in step (4), the power of the ultrasonic drying is 200-500 W, for example, it can be 200 W, 250 W, 300 W, 350 W, 400 W, 450 W, 500 W, etc., the temperature of the ultrasonic drying is 65-85 °C, for example, it can be 65 °C, 68 °C, 70 °C, 72 °C, 75 °C, 78 °C, 80 °C, 82 °C, 85 °C, etc., and the time of the ultrasonic drying is 3-3.5 h, for example, it can be 3 h, 3.1 h, 3.2 h, 3.3 h, 3.4 h, 3.5 h, etc.

[0060] In a third aspect, the present invention provides an application of the red mud-based solid adsorbent material as described in the first aspect or the red mud-based solid adsorbent material prepared by the preparation method as described in the second aspect as a carbon dioxide adsorbent.

[0061] In a fourth aspect, the present invention provides a method for adsorbing carbon dioxide. The method for adsorbing carbon dioxide includes the following steps:

[0062] Contacting the gas containing carbon dioxide with the red mud-based solid adsorbent material as described in the first aspect or the red mud-based solid adsorbent material prepared by the preparation method as described in the second aspect, and carrying out an adsorption reaction to realize the mineralization of carbon dioxide.

[0063] Preferably, the content of carbon dioxide in the gas containing carbon dioxide is 15-100%, for example, it can be 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, etc.

[0064] Preferably, the temperature of the adsorption reaction is 20-60 °C, for example, it can be 20 °C, 25 °C, 30 °C, 35 °C, 40 °C, 45 °C, 50 °C, 55 °C, 60 °C, etc., and the time of the adsorption reaction is 30-120 min, for example, it can be 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min, 120 min, etc.

[0065] Compared with the prior art, the present invention has the following beneficial effects:

[0066] (1) The red mud-based solid adsorbent material of the present invention has a high-activity adsorption matrix as the core, and this core has a multi-level pore structure; a high-activity zinc-coordinated imidazole organic framework layer shell is formed, and a porous nano-layer is formed to form CO 2Fast adsorption channels; and polyethyleneimine is attached to the voids between the imidazole organic framework layers coordinated with zinc in the adsorption matrix; the red mud-based solid adsorption material improves the adsorption capacity for CO 2 by coupling chemical adsorption and physical adsorption.

[0067] (2)The red mud-based solid adsorption material of the present invention has high adsorption capacity, high selectivity and high stability, and can simultaneously realize the mineralization of CO 2 . Detailed implementation manners

[0068] Unless otherwise defined herein, scientific and technical terms used in conjunction with the present invention shall have the meanings commonly understood by those of ordinary skill in the art. The meanings and scopes of the terms should be clear. However, in any case of potential ambiguity, the definitions provided herein shall prevail over any dictionary or extrinsic definition. In this application, unless otherwise specified, the use of "or" means "and / or". In addition, the use of the term "comprising" and other forms is non-restrictive.

[0069] It should be noted that specific details are set forth in the following description to facilitate a thorough understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar generalizations without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific implementation manners disclosed below.

[0070] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0071] The present invention will be further described below through embodiments. Unless otherwise specified, the materials in the embodiments are prepared according to existing methods or directly purchased from the market.

[0072] Example 1

[0073] This example provides a red mud-based solid adsorption material, which is prepared by the following steps:

[0074] (1)Preparation of the precursor of the adsorption matrix

[0075] The red mud was dried at 80 °C for 2 h to obtain dried red mud with a water content of 11 wt%; the coal gangue was crushed to a particle size of less than 0.5 mm to obtain coal gangue powder; the bamboo was crushed to a particle size of less than 2 mm to obtain bamboo powder; 100 parts of the dried red mud, 60 parts of the coal gangue powder and 20 parts of the bamboo powder were added to a mixer and stirred at a speed of 100 r / min for 30 min to obtain a mixed raw material powder; the mixed raw material powder was sent to a calcination kiln for calcination. After calcination at 600 °C for 1.8 h, magnetic separation was carried out to remove magnetic materials, and the precursor of the adsorption matrix was obtained.

[0076] (2)Preparation of modified adsorption matrix

[0077] Take 100 parts of the precursor of the adsorption matrix and 20 parts of calcium oxide and place them in an aqueous solution of 10 wt% PEG-400, and stir at a speed of 400 r / min for 4 h; after suction filtration and centrifugation, dry at 105 °C for 12 h; after drying, calcine at 800 °C for 2 h to obtain the adsorption matrix.

[0078] (3)Preparation of zinc-coordinated imidazole organic framework layer

[0079] Dissolve 10 parts of Zn(NO 3 ) 2 •6H 2 O and 22 parts of 2-methylimidazole in 100 parts of ethylene glycol to obtain a solution containing zinc salt and imidazole compound; place 10 parts of the adsorption matrix in 100 parts of the solution containing zinc salt and imidazole compound, and stir at a speed of 800 r / min for 40 min to obtain a mixed solution; then place the mixed solution in a microwave vacuum heating furnace and carry out microwave heating at 300 W and 160 °C for 10 min; naturally cool to 60 °C, and let it stand at 60 °C for 18 h to spontaneously crystallize. Filter the obtained crystals, wash them with ethylene glycol solution for 10 min, and then dry to obtain the initial product of the red mud-based solid adsorbent material.

[0080] (4)Preparation of finished product of red mud-based solid adsorbent material

[0081] Dissolve 12 parts of polyethyleneimine in 120 parts of methanol to obtain a polyethyleneimine solution; place 50 parts of the initial product of the red mud-based solid adsorbent material in 100 parts of the polyethyleneimine solution, impregnate at 50 °C for 1.2 h, and finally dry with ultrasonic waves at 350 W and dry at 70 °C for 3.2 h to obtain the red mud-based solid adsorbent material.

[0082] Example 2

[0083] This example provides a red mud-based solid adsorbent material, which is prepared by the following steps:

[0084] (1) Preparation of the precursor of the adsorption matrix

[0085] The red mud was dried at 60 °C for 3 h to obtain dry red mud with a water content of 10 wt%; the coal gangue was crushed to a particle size of less than 0.5 mm to obtain coal gangue powder; the walnut shell was crushed to a particle size of less than 2 mm to obtain walnut powder; 100 parts of dry red mud, 60 parts of coal gangue powder and 20 parts of walnut powder were added to a mixer and stirred at a speed of 120 r / min for 30 min to obtain a mixed raw material powder; the mixed raw material powder was sent to a calcination kiln for calcination, calcined at 500 °C for 2 h and then subjected to magnetic separation to remove magnetic materials to obtain the precursor of the adsorption matrix.

[0086] (2)Preparation of the modified adsorption matrix

[0087] Take 100 parts of the precursor of the adsorption matrix and 25 parts of calcium oxide and place them in an aqueous solution of 10 wt% PEG-400, and stir at a speed of 400 r / min for 4 h; after suction filtration and centrifugation, dry at 105 °C for 12 h; after drying, calcine at 700 °C for 3 h to obtain the adsorption matrix.

[0088] (3)Preparation of the zinc-coordinated imidazole organic framework layer

[0089] Dissolve 9.5 parts of Zn(NO 3 ) 2 •6H 2 O and 21 parts of 2-methylimidazole in 100 parts of ethylene glycol to obtain a solution containing zinc salt and imidazole compound; place 10 parts of the adsorption matrix in 80 parts of the solution containing zinc salt and imidazole compound, and stir at a speed of 900 r / min for 30 min to obtain a mixed solution; then place the mixed solution in a microwave vacuum heating furnace and carry out microwave heating at 400 W and 180 °C for 15 min; naturally cool to 60 °C and stand at 60 °C for 24 h to allow spontaneous crystallization, filter the obtained crystals, wash with ethylene glycol solution for 10 min, and then dry to obtain the primary product of the red mud-based solid adsorption material.

[0090] (4)Preparation of the finished product of the red mud-based solid adsorption material

[0091] Dissolve 12 parts of polyethyleneimine in 120 parts of methanol to obtain a polyethyleneimine solution; place 60 parts of the primary product of the red mud-based solid adsorption material in 100 parts of the polyethyleneimine solution, immerse it at 60 °C for 1 h, and finally dry it with ultrasonic waves at 400 W and dry it at 75 °C for 3 h to obtain the red mud-based solid adsorption material.

[0092] Example 3

[0093] This embodiment provides a red mud-based solid adsorbent material, and the red mud-based solid adsorbent material is prepared by the following steps:

[0094] (1) Preparation of the precursor of the adsorption matrix

[0095] The red mud is dried at 60 °C for 3 h to obtain dried red mud with a water content of 10 wt%; the coal gangue is crushed to a particle size of less than 0.5 mm to obtain coal gangue powder; the bamboo, walnut shell, and peanut shell are respectively crushed to a particle size of less than 2 mm to obtain bamboo powder, walnut shell powder, and peanut shell powder; 100 parts of the dried red mud, 60 parts of the coal gangue powder, 4 parts of the bamboo powder, 3 parts of the walnut shell powder, and 3 parts of the peanut shell powder are added to a mixer and stirred at a speed of 80 r / min for 40 min to obtain a mixed raw material powder; the mixed raw material powder is sent to a calcination kiln for calcination, calcined at 700 °C for 1.5 h, and then subjected to magnetic separation to remove magnetic materials to obtain the precursor of the adsorption matrix.

[0096] (2) Preparation of the modified adsorption matrix

[0097] Take 100 parts of the precursor of the adsorption matrix and 15 parts of calcium oxide and place them in an aqueous solution of 10 wt% PEG-400, and stir at a speed of 400 r / min for 4 h; after suction filtration and centrifugation, dry at 105 °C for 12 h; after drying, calcine at 850 °C for 1.5 h to obtain the adsorption matrix.

[0098] (3) Preparation of the zinc-coordinated imidazole organic framework layer

[0099] Dissolve 8 parts of Zn(NO 3 ) 2 •6H 2 O and 26 parts of 2-methylimidazole in 100 parts of ethylene glycol to obtain a solution containing zinc salt and imidazole compounds; place 10 parts of the adsorption matrix in 60 parts of the solution containing zinc salt and imidazole compounds, and stir at a speed of 600 r / min for 50 min to obtain a mixed solution; then place the mixed solution in a microwave vacuum heating furnace and carry out microwave heating at 300 W and 170 °C for 5 min; naturally cool to 60 °C, and let it stand at 60 °C for 12 h to spontaneously crystallize, filter the obtained crystals, wash them with an ethylene glycol solution for 10 min, and then dry to obtain the initial product of the red mud-based solid adsorbent material.

[0100] (4)Preparation of the finished product of the red mud-based solid adsorbent material

[0101] Dissolve 6 parts of polyethyleneimine in 120 parts of methanol to obtain a polyethyleneimine solution; place 60 parts of the initial product of the red mud-based solid adsorbent material in 100 parts of the polyethyleneimine solution, impregnate at 50 °C for 1.5 h, and finally dry with ultrasonic waves at 300 W and dry at 70 °C for 3.5 h to obtain the red mud-based solid adsorbent material.

[0102] Example 4

[0103] This example provides a red mud-based solid adsorbent material, which is different from Example 1 in that in step (1), 100 parts of dry red mud, 40 parts of coal gangue powder, and 40 parts of bamboo powder are added to a mixer, and the other steps are exactly the same as those in Example 1.

[0104] Example 5

[0105] This example provides a red mud-based solid adsorbent material, which is different from Example 1 in that in step (1), 100 parts of dry red mud, 75 parts of coal gangue powder, and 5 parts of bamboo powder are added to a mixer, and the other steps are exactly the same as those in Example 1.

[0106] Example 6

[0107] This example provides a red mud-based solid adsorbent material, which is different from Example 1 in that in step (1), 80 parts of dry red mud, 80 parts of coal gangue powder, and 20 parts of bamboo powder are added to a mixer, and the other steps are exactly the same as those in Example 1.

[0108] Example 7

[0109] This example provides a red mud-based solid adsorbent material, which is different from Example 1 in that in step (2), 100 parts of the precursor of the adsorption matrix and 5 parts of calcium oxide are placed in an aqueous solution of 10 wt% PEG-400, and the other steps are exactly the same as those in Example 1.

[0110] Example 8

[0111] This example provides a red mud-based solid adsorbent material, which is different from Example 1 in that in step (2), 100 parts of the precursor of the adsorption matrix and 25 parts of calcium oxide are placed in an aqueous solution of 10 wt% PEG-400, and the other steps are exactly the same as those in Example 1.

[0112] Example 9

[0113] This example provides a red mud-based solid adsorbent material, which is different from Example 1 in that in step (2), the aqueous solution of 10 wt% PEG-400 is replaced with an aqueous solution of 10 wt% PEG-200, and the other steps are exactly the same as those in Example 1.

[0114] Example 10

[0115] This example provides a red mud-based solid adsorption material. The difference from Example 1 is that in step (2), the aqueous solution of 10 wt% PEG-400 is replaced with an aqueous solution of 10 wt% PEG-800, and the other steps are exactly the same as those in Example 1.

[0116] Example 11

[0117] This example provides a red mud-based solid adsorption material. The difference from Example 1 is that in step (3), the mixed solution is not placed in a microwave vacuum heating furnace but in a common heating and stirring device, and heated and stirred at 170 °C for 2 h, and the other steps are exactly the same as those in Example 1.

[0118] Example 12

[0119] This example provides a red mud-based solid adsorption material. The difference from Example 1 is that in step (4), ultrasonic drying is not carried out, but it is placed in a vacuum drying oven and dried for 12 h, and the other steps are exactly the same as those in Example 1.

[0120] Comparative Example 1

[0121] This comparative example provides a solid adsorption material, which is prepared by the following steps:

[0122] The red mud is dried at 80 °C for 2 h to obtain dried red mud with a water content of 11 wt%; the coal gangue is crushed to a particle size of less than 0.5 mm to obtain coal gangue powder; the bamboo is crushed to a particle size of less than 2 mm to obtain bamboo powder; 100 parts of dried red mud, 60 parts of coal gangue powder and 20 parts of bamboo powder are added to a mixer and stirred at a speed of 100 r / min for 30 min to obtain a mixed raw material powder; the mixed raw material powder is sent to a calcination kiln for calcination, magnetically separated to remove magnetic materials after calcination at 600 °C for 1.8 h, and a solid adsorption material is obtained.

[0123] Comparative Example 2

[0124] This comparative example provides a red mud-based solid adsorption material, which is prepared by the following steps:

[0125] (1) Preparation of the precursor of the adsorption matrix

[0126] The red mud was dried at 80 °C for 2 h to obtain dried red mud with a water content of 11 wt%; the coal gangue was crushed to a particle size of less than 0.5 mm to obtain coal gangue powder; the bamboo was crushed to a particle size of less than 2 mm to obtain bamboo powder; 100 parts of the dried red mud, 60 parts of the coal gangue powder and 20 parts of the bamboo powder were added to a mixer and stirred at a speed of 100 r / min for 30 min to obtain a mixed raw material powder; the mixed raw material powder was sent to a calcination kiln for calcination, calcined at 600 °C for 1.8 h and then subjected to magnetic separation to remove magnetic materials to obtain the precursor of the adsorption matrix.

[0127] (2)Preparation of modified adsorption matrix

[0128] Take 100 parts of the precursor of the adsorption matrix and 5 parts of calcium oxide and place them in an aqueous solution of 10 wt% PEG-400, and stir at a speed of 400 r / min for 4 h; after suction filtration and centrifugation, dry at 105 °C for 12 h; after drying, calcine at 800 °C for 2 h to obtain the red mud-based solid adsorption material.

[0129] Comparative Example 3

[0130] This comparative example provides a red mud-based solid adsorption material, which is prepared by the following steps:

[0131] (1)Preparation of precursor of adsorption matrix

[0132] The red mud was dried at 80 °C for 2 h to obtain dried red mud with a water content of 11 wt%; the coal gangue was crushed to a particle size of less than 0.5 mm to obtain coal gangue powder; the bamboo was crushed to a particle size of less than 2 mm to obtain bamboo powder; 100 parts of the dried red mud, 60 parts of the coal gangue powder and 20 parts of the bamboo powder were added to a mixer and stirred at a speed of 100 r / min for 30 min to obtain a mixed raw material powder; the mixed raw material powder was sent to a calcination kiln for calcination, calcined at 600 °C for 1.8 h and then subjected to magnetic separation to remove magnetic materials to obtain the precursor of the adsorption matrix.

[0133] (2)Preparation of modified adsorption matrix

[0134] Take 100 parts of the precursor of the adsorption matrix and 5 parts of calcium oxide and place them in an aqueous solution of 10 wt% PEG-400, and stir at a speed of 400 r / min for 4 h; after suction filtration and centrifugation, dry at 105 °C for 12 h; after drying, calcine at 800 °C for 2 h to obtain the adsorption matrix.

[0135] (3)Preparation of zinc-coordinated imidazole organic framework layer

[0136] Add 10 parts of Zn(NO 3 ) 2•6H 2 6H₂O and 22 parts of 2-methylimidazole are dissolved in 100 parts of ethylene glycol to obtain a solution containing a zinc salt and an imidazole compound; 10 parts of an adsorption matrix are placed in 100 parts of the solution containing the zinc salt and the imidazole compound, and stirred at a speed of 800 r / min for 40 min to obtain a mixture; then the mixture is placed in a microwave vacuum heating furnace and microwave-heated at 300 W and 160 °C for 10 min; it is naturally cooled to 60 °C and left to stand at 60 °C for 18 h for spontaneous crystallization, the obtained crystals are filtered, washed with an ethylene glycol solution for 10 min, and then dried to obtain a red mud-based solid adsorption material.

[0137] Comparative Example 4

[0138] This comparative example provides a red mud-based solid adsorption material, and the red mud-based solid adsorption material is prepared by the following steps:

[0139] (1) Preparation of the adsorption matrix

[0140] The red mud is dried at 80 °C for 2 h to obtain dry red mud with a water content of 11 wt%; the coal gangue is crushed to a particle size of less than 0.5 mm to obtain coal gangue powder; the bamboo is crushed to a particle size of less than 2 mm to obtain bamboo powder; 100 parts of the dry red mud, 60 parts of the coal gangue powder and 20 parts of the bamboo powder are added to a mixer and stirred at a speed of 100 r / min for 30 min to obtain a mixed raw material powder; the mixed raw material powder is sent to a calcination kiln for calcination, calcined at 600 °C for 1.8 h and then subjected to magnetic separation to remove magnetic materials to obtain the adsorption matrix.

[0141] (2) Preparation of the zinc-coordinated imidazole organic framework layer

[0142] 10 parts of Zn(NO 3 ) 2 •6H 2 ₂O and 22 parts of 2-methylimidazole are dissolved in 100 parts of ethylene glycol to obtain a solution containing a zinc salt and an imidazole compound; 10 parts of the adsorption matrix are placed in 100 parts of the solution containing the zinc salt and the imidazole compound, and stirred at a speed of 800 r / min for 40 min to obtain a mixture; then the mixture is placed in a microwave vacuum heating furnace and microwave-heated at 300 W and 160 °C for 10 min; it is naturally cooled to 60 °C and left to stand at 60 °C for 18 h for spontaneous crystallization, the obtained crystals are filtered, washed with an ethylene glycol solution for 10 min, and then dried to obtain a preliminary product of the red mud-based solid adsorption material.

[0143] (3) Preparation of the finished product of the red mud-based solid adsorption material

[0144] Dissolve 12 parts of polyethyleneimine in 120 parts of methanol to obtain a polyethyleneimine solution; place 50 parts of the initial product of the red mud-based solid adsorbent material in 100 parts of the polyethyleneimine solution, impregnate it at 50 °C for 1.2 h, and finally dry it with ultrasonic waves at 350 W and dry it at 70 °C for 3.2 h to obtain the red mud-based solid adsorbent material.

[0145] Comparative Example 5

[0146] This comparative example provides a red mud-based solid adsorbent material, which is prepared by the following steps:

[0147] (1) Preparation of the precursor of the adsorption matrix

[0148] Dry red mud at 80 °C for 2 h to obtain dry red mud with a water content of 11 wt%; crush coal gangue to a particle size of less than 0.5 mm to obtain coal gangue powder; crush bamboo to a particle size of less than 2 mm to obtain bamboo powder; add 100 parts of dry red mud, 60 parts of coal gangue powder and 20 parts of bamboo powder to a mixer, stir at a speed of 100 r / min for 30 min to obtain a mixed raw material powder; send the mixed raw material powder to a calcination kiln for calcination, calcine at 600 °C for 1.8 h, and then perform magnetic separation to remove magnetic materials to obtain the precursor of the adsorption matrix.

[0149] (2) Preparation of the modified adsorption matrix

[0150] Take 100 parts of the precursor of the adsorption matrix and 5 parts of calcium oxide and place them in an aqueous solution of 10 wt% PEG-400, stir at a speed of 400 r / min for 4 h; after suction filtration and centrifugation, dry at 105 °C for 12 h; after drying, calcine at 800 °C for 2 h to obtain the adsorption matrix.

[0151] (3) Preparation of the finished product of the red mud-based solid adsorbent material

[0152] Dissolve 12 parts of polyethyleneimine in 120 parts of methanol to obtain a polyethyleneimine solution; place 50 parts of the adsorption matrix in 100 parts of the polyethyleneimine solution, impregnate it at 50 °C for 1.2 h, and finally dry it with ultrasonic waves at 350 W and dry it at 70 °C for 3.2 h to obtain the red mud-based solid adsorbent material.

[0153] Comparative Example 6

[0154] This comparative example provides a solid adsorbent material, which is only different from Example 7 in that in step (1), no dry red mud is added, the content of coal gangue powder is increased to 90 parts, and the content of bamboo powder is increased to 90 parts, and the other steps are exactly the same as those in Example 7.

[0155] Comparative Example 7

[0156] This comparative example provides a solid adsorbent material, which is only different from Example 7 in that in step (1), no coal gangue powder is added, the content of dried red mud is increased to 90 parts, and the content of bamboo powder is increased to 90 parts, and the other steps are exactly the same as those in Example 7.

[0157] Comparative Example 8

[0158] This comparative example provides a solid adsorbent material, which is only different from Example 7 in that in step (1), no bamboo powder is added, the content of dried red mud is increased to 90 parts, and the content of coal gangue powder is increased to 90 parts, and the other steps are exactly the same as those in Example 7.

[0159] Test Example 1

[0160] Particle size and pore size test of the adsorbent material

[0161] Test samples: the solid adsorbent materials provided in Examples 1 to 12, and the solid adsorbent materials provided in Comparative Examples 1 to 8;

[0162] Test method: Use SEM to test the specific surface area, pore volume and pore size of the solid adsorbent material respectively.

[0163] The specific test results are shown in Table 1:

[0164] Table 1

[0165]

[0166] As shown in Table 1, the specific surface area of the red mud-based solid adsorbent material of the present invention is 800 m 2 / g or more, the pore volume is 0.3 cm 3 / g or more, and the pore diameter is 2.4 nm or less; among them, Examples 1 to 3 are the most preferred technical solutions of the present invention, and their specific surface area can reach 1050 m 2 / g or more, the pore volume can reach 0.4 cm 3 / g or more, and the average pore diameter reaches 1.9 nm or less. This shows that the material prepared by the method of the present invention has a large specific surface area, a large pore volume and a small average pore diameter.

[0167] Test Example 2

[0168] Adsorption capacity test of the adsorbent material

[0169] Test samples: the solid adsorbent materials provided in Examples 1 to 12, and the solid adsorbent materials provided in Comparative Examples 1 to 8;

[0170] Test method:

[0171] (1) Static adsorption: The adsorption performance of the solid adsorption material was characterized by the static capacity adsorption method. Under normal pressure (101.3 kPa) and at room temperature of 25 °C, the solid adsorption material was placed in a closed container, and CO 2 was introduced to test the adsorption capacity of the above solid adsorption material.

[0172] (2) Dynamic adsorption: The adsorption performance of the solid adsorption material was characterized by the dynamic adsorption method. Under normal pressure, simulating the CO 2 gas flow rate of 50 cm 3 / min and at room temperature of 25 °C, the adsorption capacity of the above solid adsorption material was tested.

[0173] The specific test results are shown in Table 2:

[0174] Table 2

[0175]

[0176] As shown in Table 2 above, the static adsorption capacity of the red mud-based solid adsorption material prepared by the method of the present invention is 3.0 - 3.5 mmol / g, and the dynamic adsorption capacity is 2.4 - 2.8 mmol / g. This shows that the present invention uses red mud and coal gangue solid waste as raw materials to prepare a carbon dioxide adsorbent. With highly active SiO 2 , Al 2 O 3 and CaO as the core matrix, multi-level pores are formed by accelerating modification, and then a porous nano-layer is formed on the surface to form a CO 2 rapid adsorption channel, and then impregnated with organic amine to obtain a solid amine carbon dioxide adsorbent. This application couples chemical adsorption and physical adsorption, improving the adsorption capacity for CO 2 .

[0177] Test Example 3

[0178] Selectivity test of the adsorption material

[0179] Test samples: The solid adsorption materials provided in Examples 1 - 12, the solid adsorption materials provided in Comparative Examples 1 - 8;

[0180] Test method: Take 100 mg of each of the above solid adsorption materials and place them in an ASAP2020 specific surface area and pore size analyzer for adsorption at a certain pressure and temperature. Finally, measure the adsorption amounts of each adsorbent for CO 2 , N 2 and CH 2 respectively, and calculate the CO 2 / CH 4 separation selectivity and CO 2 / N 2 separation selectivity of each adsorbent.

[0181] The specific test results are shown in Table 3 as follows:

[0182] Table 3

[0183]

[0184] As shown in Table 3, the CO 2 / CH 4 separation selectivity of the red mud-based solid adsorbent prepared by the method of the present invention is above 12, and the CO 2 / N 2 separation selectivity is above 13.5. This shows that the red mud-based solid adsorbent of the present invention has excellent separation selectivity for CO 2 and can obtain high selectivity that meets the requirements of industrial carbon dioxide adsorption.

[0185] Test Example 4

[0186] Cyclic stability test of the adsorbent

[0187] Test samples: the solid adsorbents provided in Examples 1 to 12 and the solid adsorbents provided in Comparative Examples 1 to 8;

[0188] Test method: Perform a CO 2 adsorption-regeneration cycle performance test on the above adsorbents. Adsorption conditions: under normal pressure (101.3 kPa), pure CO 2 gas at a constant temperature of 25 °C for 1 h of isothermal and isobaric adsorption of CO2; after the adsorption is completed, the adsorbent is regenerated; regeneration conditions: regenerate for 20 min at 120 °C and 100% N 2 . Perform 60 adsorption-regeneration cycle tests on the adsorbent. Among them, the CO 2 adsorption capacity results of the 10th, 30th, and 60th times are shown in Table 1.

[0189] The specific test results are shown in Table 4 as follows:

[0190] Table 4

[0191]

[0192] As shown in Table 4, the adsorbent of the present invention has a large CO 2 adsorption capacity. After 60 cycle tests, it still has a high CO 2 adsorption capacity, and the adsorption capacity can still reach above 1.90 mmol / g. The adsorbent of the present invention has excellent CO 2 adsorption stability.

[0193] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A red mud-based solid adsorption material, characterized in that: The red mud-based solid adsorption material comprises an adsorption matrix formed by calcining and modifying red mud, coal gangue and biomass, the surface of the adsorption matrix has a zinc-coordinated imidazole organic framework layer; and polyethyleneimine is attached to the gap between the adsorption matrix and the zinc-coordinated imidazole organic framework layer; The mass ratio of red mud, coal gangue and biomass is 1.0:(0.4-1.0):(0.1-0.3); The red mud-based solid adsorption material is prepared by the following preparation method: (1) After mixing red mud, coal gangue and biomass, calcining them for the first time to obtain a precursor of the adsorption matrix; the temperature of the first calcination is 400-800° C., and the time of the first calcination is 1.5-2 h; (2) placing the precursor of the adsorption matrix and calcium oxide in a polyethylene glycol solution, stirring the reaction, collecting the product, and then calcining for a second time to obtain the adsorption matrix; the stirring reaction temperature is 10-40° C., and the stirring reaction time is 2-6 h; the second calcination temperature is 700-850° C., and the second calcination time is 1-3 h; (3) placing the adsorption matrix in a solution containing zinc salt and imidazole compounds and stirring the solution, and then sequentially performing microwave heating reaction, so that a zinc-coordinated imidazole organic framework layer is attached to the surface of the adsorption matrix, thereby obtaining a primary product of a red mud-based solid adsorption material; (4) After immersing the primary product in the polyethyleneimine solution, the product is taken out and subjected to ultrasonic drying treatment, so that polyethyleneimine is attached to the gaps between the adsorption matrix and the zinc-coordinated imidazole organic framework layer, thereby obtaining the red mud-based solid adsorption material.

2. The red mud-based solid adsorption material according to claim 1, characterized in that: The specific surface area of ​​the red mud-based solid adsorption material is 800 m 2 / g or more; And / or, the pore volume of the red mud-based solid adsorption material is 0.3 cm 3 / g or more; And / or, the pore size of the red mud-based solid adsorption material is less than 2.4 nm.

3. The red mud-based solid adsorption material according to claim 1, characterized in that: The biomass is selected from any one of bamboo, walnut shells, peanut shells, straw or corn cobs, or a combination of at least two of them.

4. A method for preparing a red mud-based solid adsorption material according to any one of claims 1 to 3, characterized in that: The preparation method specifically comprises the following steps: (1) After mixing red mud, coal gangue and biomass, calcining them for the first time to obtain a precursor of the adsorption matrix; the temperature of the first calcination is 400-800° C., and the time of the first calcination is 1.5-2 h; (2) placing the precursor of the adsorption matrix and calcium oxide in a polyethylene glycol solution, stirring the reaction, collecting the product, and then calcining for a second time to obtain the adsorption matrix; the stirring reaction temperature is 10-40° C., and the stirring reaction time is 2-6 h; the second calcination temperature is 700-850° C., and the second calcination time is 1-3 h; (3) placing the adsorption matrix in a solution containing zinc salt and imidazole compounds and stirring the solution, and then sequentially performing microwave heating reaction, so that a zinc-coordinated imidazole organic framework layer is attached to the surface of the adsorption matrix, thereby obtaining a primary product of a red mud-based solid adsorption material; (4) After immersing the primary product in the polyethyleneimine solution, the product is taken out and subjected to ultrasonic drying treatment, so that polyethyleneimine is attached to the gaps between the adsorption matrix and the zinc-coordinated imidazole organic framework layer, thereby obtaining the red mud-based solid adsorption material.

5. The method for preparing a red mud-based solid adsorption material according to claim 4, characterized in that: In step (1), pretreatment is required before mixing: The red mud is dried at 60-110°C for 1-3 h to obtain red mud with a water content of 5-20 wt%; Grinding the coal gangue to a particle size of less than 0.5 mm to obtain coal gangue powder; The biomass is crushed to a particle size of less than 2 mm to obtain biomass powder; And / or, in step (1), the mixing speed is 40-120 r / min, and the mixing time is 20-40 min.

6. The method for preparing a red mud-based solid adsorption material according to claim 4, characterized in that: In step (2), the mass ratio of the precursor of the adsorption matrix to calcium oxide is 1:(0.1-0.3); And / or, in step (2), the polyethylene glycol solution is a 5-15 wt% aqueous solution of PEG-400; And / or, in step (2), the collecting of the product is specifically: firstly filtering and / or centrifuging to collect the solid, and then drying the solid at 100-110° C. for 10-15 h; And / or, in step (2), the second calcination further comprises a crushing step, wherein the crushing step is performed until the particle size of the adsorption matrix is ​​200-500 μm.

7. The method for preparing a red mud-based solid adsorption material according to claim 4, characterized in that: In step (3), the zinc salt is zinc nitrate; the imidazole compound is 2-methylimidazole; and the solvent of the solution is ethylene glycol; And / or, in step (3), the solution containing zinc salt and imidazole compound comprises, by weight: 5-15 parts of zinc salt, 20-30 parts of imidazole compound and 80-120 parts of solvent; And / or, in step (3), the stirring speed is 500-1000 r / min, and the stirring time is 30-60 min; And / or, in step (3), the microwave power of the microwave heating reaction is 200-400 W, the temperature of the microwave heating reaction is 120-180° C., and the time of the microwave heating reaction is 5-15 min; And / or, in step (3), the microwave heating reaction further includes a post-treatment step: naturally cooling to room temperature, standing at room temperature for 12 to 24 hours, filtering to obtain crystals; then washing with ethylene glycol solution, and drying to obtain the initial product of red mud-based solid adsorption material.

8. The method for preparing a red mud-based solid adsorption material according to claim 4, characterized in that: In step (4), the solid-liquid ratio of the primary product to the polyethyleneimine solution is 1:(5-10); And / or, in step (4), the molecular weight of the polyethyleneimine is 10000-30000; And / or, in step (4), the polyethyleneimine solution is a 5-10 wt% polyethyleneimine methanol solution; And / or, in step (4), the immersion temperature is 30-60° C., and the immersion time is 1-1.5 h; And / or, in step (4), the power of the ultrasonic drying is 200-500 W, the temperature of the ultrasonic drying is 65-85° C., and the time of the ultrasonic drying is 3-3.5 h.

9. Use of the red mud-based solid adsorption material according to any one of claims 1 to 3, or the red mud-based solid adsorption material prepared by the preparation method according to any one of claims 4 to 8 as a carbon dioxide adsorbent.

10. A method for adsorbing carbon dioxide, characterized in that: The carbon dioxide adsorption method comprises the following steps: The gas containing carbon dioxide is brought into contact with the red mud-based solid adsorption material according to any one of claims 1 to 3, or the red mud-based solid adsorption material prepared by the preparation method according to any one of claims 4 to 8, and an adsorption reaction is carried out to achieve mineralization of carbon dioxide.

11. The method for adsorbing carbon dioxide according to claim 10, characterized in that: The carbon dioxide content in the carbon dioxide-containing gas is 10-100%.

12. The method for adsorbing carbon dioxide according to claim 10, characterized in that: The temperature of the adsorption reaction is 20-60° C., and the time of the adsorption reaction is 30-120 min.

Images