A preparation method of zirconium-carbon integrated adsorbent for efficient purification of biogas

Abstract

The application discloses a preparation method of zirconium-carbon integrated adsorbent for efficiently purifying marsh gas, which comprises the following steps: first, preparing high-performance carbon material based on kitchen waste: mixing kitchen waste and deionized water to perform hydrothermal reaction, obtaining a solid-liquid mixture, performing solid-liquid separation on the solid-liquid mixture by using a vacuum filtration device, performing chemical activation and physical activation on the solid phase obtained by the solid-liquid separation, and obtaining the high-performance carbon material; then, preparing a double-ligand zirconium metal organic framework: dissolving zirconium chloride, 2-amino terephthalic acid and 2,5-dihydroxy terephthalic acid in DMF, performing solvothermal reaction, washing the double-ligand zirconium metal organic framework with DMF and methanol alternately for three times, performing centrifugation and drying, and obtaining the double-ligand zirconium metal organic framework; finally, compounding the double-ligand zirconium metal organic framework and the high-performance carbon material by using a microwave-assisted method, and obtaining the zirconium-carbon integrated adsorbent. The application can enhance the stability of the adsorbent and improve the marsh gas separation and purification capacity of the adsorbent.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of biogas purification and upgrading, and particularly relates to a composite material obtained by compounding a high-performance carbon material prepared from kitchen waste and a double-ligand zirconium-based MOF for use in the field of biogas separation and purification, and more particularly to a preparation method of a zirconium-carbon integrated adsorbent for efficient purification of biogas. BACKGROUND

[0002] The annual output of kitchen waste is huge, and if the kitchen waste is not effectively recycled and utilized, it will not only cause serious resource waste, but also easily lead to a series of environmental and public health safety problems. The hydrothermal treatment technology of kitchen waste is to apply the hydrothermal technology to the treatment of solid waste kitchen waste, that is, to place the kitchen waste in a sealed reactor and heat it in a water environment to make the kitchen waste undergo a series of reactions. The kitchen waste can be quickly and comprehensively recycled by using the hydrothermal treatment technology. The solid product of hydrothermal treatment can be used to prepare high-performance carbon materials, and the liquid product thereof can be used to ferment and prepare biogas.

[0003] As a renewable energy source, biogas has the potential to play a key role in the world's energy supply and diversification. However, the content of carbon dioxide (CO2) in biogas is relatively high, about 35% to 40%, which not only aggravates the greenhouse effect, but also reduces the overall heat value of biogas. Therefore, the industrial treatment of biogas needs to upgrade the biogas, which involves the capture of CO2. The method of CO2 capture for biogas upgrading puts forward higher requirements, so the separation and purification of biogas needs an excellent disposal method.

[0004] Metal-organic frameworks (MOFs) are a kind of three-dimensional porous crystalline material formed by organic ligands and metal clusters through coordination bonds, which have been widely studied in recent years. Zirconium-based metal-organic framework materials have advantages in biogas separation and purification due to their excellent thermal stability and chemical stability, high selectivity for CO2 / CH4, and strong regeneration ability. Carbon materials are also a kind of materials with porous structure, which have been widely used in the field of gas adsorption and separation. Therefore, combining high-performance carbon materials and zirconium-based MOFs to prepare composite adsorbents can not only efficiently utilize kitchen waste, but also efficiently separate and purify biogas. SUMMARY

[0005] The present application aims to provide a preparation method of a zirconium-carbon integrated adsorbent for efficient purification of biogas to overcome the shortcomings of the prior art. The present application can not only efficiently utilize kitchen waste, but also obtain high-purity methane (CH4) for more extensive applications.

[0006] The purpose of the present application is achieved by the following technical solution: a preparation method of a zirconium-carbon integrated adsorbent for efficient purification of biogas, comprising the following steps:

[0007] (1)Preparation of high-performance carbon materials based on kitchen waste: first, the kitchen waste is mixed with deionized water and placed in a hydrothermal reactor, and the hydrothermal reaction is carried out at a temperature of 240-280℃ for 30-60min, and then the hydrothermal reactor is cooled to 20℃ by circulating cooling water; then the obtained solid-liquid mixture is separated by vacuum filtration device, and the obtained solid phase is dried in a drying oven and then ground to obtain powder hydrochar; then the hydrochar is mixed with a chemical activator in a mass ratio of 1:2 and deionized water is added and mixed thoroughly, and then placed in a drying oven to dry, and the chemical activator is potassium bicarbonate; secondly, the solid powder is placed in a tube furnace, nitrogen is introduced to ensure that the air in the tube furnace is completely exhausted, the activation temperature is set to 700-800℃, the activation time is 6-7h, and nitrogen is continuously introduced until the activation reaction is completed; then after the tube furnace is cooled, the obtained powder is collected and washed with 1mol / L hydrochloric acid until no bubbles are generated, then washed with deionized water until the filtrate is neutral, and then vacuum filtration is performed using a vacuum filtration device, and then placed in a drying oven for drying, and the obtained solid powder is further ground and placed in a high-purity carbon dioxide atmosphere for physical activation to obtain high-performance carbon materials, wherein the purity of high-purity carbon dioxide is greater than or equal to 99.9%;

[0008] (2)Preparation of zirconium-carbon integrated adsorbent by double-ligand zirconium-carbon complex: first, zirconium chloride, 2-amino terephthalic acid, and 2,5-dihydroxy terephthalic acid are dissolved in N,N-dimethylformamide, wherein the molar ratio of zirconium chloride, 2-amino terephthalic acid, 2,5-dihydroxy terephthalic acid, and DN,N-dimethylformamide is 1:1:0.1:159, and placed on a magnetic stirrer for stirring; then 1mol / L glacial acetic acid is added, stirred again, and then poured into a hydrothermal reactor with a polytetrafluoroethylene liner for solvothermal reaction, wherein the molar ratio of glacial acetic acid to zirconium chloride is 1:14; after the solvothermal reaction is completed, the hydrothermal reactor is cooled to 20℃, and the supernatant is filtered, the obtained solid phase is washed with N,N-dimethylformamide and methanol alternately for three times, and then centrifuged at a speed of 5000r / min for 5 minutes, and the obtained solid sample is placed in a vacuum drying oven for vacuum drying to obtain a double-ligand zirconium metal organic framework; finally, the prepared double-ligand zirconium metal organic framework material and the high-performance carbon material prepared in step (1) are placed in an N,N-dimethylformamide solution and stirred, then placed in a microwave container, and reacted at 120℃ for 30 minutes under static conditions to obtain a zirconium-carbon integrated adsorbent with double ligands.

[0009] Further, it also includes:

[0010] Preparation of biogas from hydrothermal liquid of kitchen waste: the same method as in step (1) is used to place kitchen waste in a hydrothermal reactor for hydrothermal reaction, and after the hydrothermal reaction is completed, it is cooled to 20 DEG C, and then a vacuum filtration device is used for filtration to separate the solid and liquid; the liquid phase after solid-liquid separation enters a separating funnel device for oil-water separation; the liquid phase after oil-water separation is used as fuel for combustion, and the organic waste liquid after oil-water separation is pumped into a medium temperature fermentation device for fermentation, and biogas is obtained after fermentation.

[0011] Further, it also includes:

[0012] Separation and purification of biogas using zirconium-carbon integrated adsorbent: the zirconium-carbon integrated adsorbent is placed in a separation device, and the biogas is sent into the separation device, and during the adsorption process of the zirconium-carbon integrated adsorbent, the tail gas is collected every fixed time for GC-TCD detection to obtain the gas content, and the adsorption selectivity of carbon dioxide / methane is calculated by a multi-component gas adsorption selectivity formula, and the zirconium-carbon integrated adsorbent used for adsorption is desorbed by increasing the temperature and reducing the pressure, and the zirconium-carbon integrated adsorbent is reused for separation and purification of the desorbed gas, until high-purity methane and carbon dioxide are obtained by separation and purification, wherein the purity of the high-purity methane and carbon dioxide is greater than or equal to 99.9%.

[0013] Further, the multi-component gas adsorption selectivity formula is represented as:

[0014]

[0015] Wherein, S is the adsorption selectivity of carbon dioxide / methane; q CO2 , q CH4 are the adsorption amounts of carbon dioxide and methane, respectively; p CO2 , p CH4 represent the partial pressures of carbon dioxide and methane, respectively.

[0016] Compared with the prior art, the beneficial effects of the present application are:

[0017] (1) The high-performance carbon material of the present application and the double-ligand zirconium-based MOF can share advantages after compounding, not only enhancing the stability of the adsorbent, but also improving the biogas separation and purification capacity of the adsorbent;

[0018] (2) The organic waste liquid separated from the hydrothermal liquid of kitchen waste in the present application is used for fermentation to produce biogas, and the oil phase separated can be used as fuel;

[0019] (3) The present application can separate biogas, and the high-purity CO2 obtained after biogas separation can be recycled for physical activation of carbon material, and the high-purity CH4 obtained after biogas separation can be used in a wider range of scenarios. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 Method flowchart of the present invention. DETAILED DESCRIPTION

[0021] The exemplary embodiments will be described in detail herein with reference to the attached drawings. The description herein relates to the drawings, in which:

[0022] The terminology used in the present invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the present invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0023] It is to be understood that the singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. It is also to be understood that the term such as "if" can be interpreted as meaning "when" or "upon" or "in response to determining" depending on the context.

[0024] The present invention will now be described in detail with reference to the drawings. The features described in the following embodiments and / or examples can be combined with each other, if not contradictory.

[0025] The present application is directed to efficient utilization of kitchen waste and biogas separation and purification, and proposes a preparation method of zirconium-carbon integrated adsorbent for efficient purification of biogas. The preparation method efficiently utilizes high-performance activated carbon after hydrothermal activation of kitchen waste and prepares zirconium-carbon integrated adsorbent by compounding double-ligand zirconium-based MOF. The zirconium-carbon integrated adsorbent prepared is applied to biogas produced by anaerobic fermentation of organic waste liquid, and can separate and purify the biogas. First, the kitchen waste is subjected to hydrothermal reaction, and the obtained solid phase is subjected to chemical activation and physical activation to prepare high-performance activated carbon with a porous structure. The obtained high-performance activated carbon and double-ligand zirconium-based MOF synthesized by a solvent-thermal method are synthesized by a microwave-assisted method to separate and purify the biogas produced by anaerobic fermentation of organic waste liquid in liquid phase. High-purity CO2 is obtained by relying on the excellent regeneration performance and high selective separation of the adsorbent. The high-purity CO2 is used in the solid-phase physical activation process, and the separated high-purity CH4 can be applied to more application scenarios. The oil phase in the liquid phase can be used as fuel for combustion.

[0026] Referring to Figure 1 The preparation method of zirconium-carbon integrated adsorbent for efficient purification of biogas according to the present application specifically includes the following steps:

[0027] (1) Preparation of high-performance carbon material based on kitchen waste: first, the kitchen waste is mixed with deionized water and placed in a hydrothermal reactor, and the hydrothermal reaction is carried out at a temperature of 240-280℃ for 30-60min. After the hydrothermal reaction is completed, the hydrothermal reactor is cooled to 20℃ by circulating cooling water. Then, the obtained solid-liquid mixture is subjected to solid-liquid separation by a vacuum filtration device, and the obtained solid phase is dried in a drying oven and then ground to obtain powdered hydrothermal coke. The hydrothermal coke is mixed with a chemical activator in a mass ratio of 1:2 and deionized water is added to mix thoroughly, and then placed in a drying oven for drying to obtain a solid powder, wherein the chemical activator is potassium bicarbonate (KHCO3). Then, the solid powder is placed in a tube furnace, nitrogen (N2) is introduced to ensure that the air in the tube furnace is completely exhausted, the activation temperature is set to 700-800℃, the activation time is 6-7h, and N2 is continuously introduced until the activation reaction is completed. After the tube furnace is cooled, the obtained powder is collected and washed with hydrochloric acid with a concentration of 1mol / L until no bubbles are generated. Then, deionized water is used for washing until the filtrate is neutral. The vacuum filtration device is used for filtration, and after the filtration process is completed, the obtained solid powder is placed in a drying oven for drying. The dried solid powder is further ground and placed in a high-purity carbon dioxide (CO2) atmosphere for physical activation, wherein the purity of the high-purity CO2 is greater than or equal to 99.9%, and a high-performance carbon material is obtained. The hydrothermal coke obtained based on kitchen waste is activated by chemical and physical activation methods, and a high-performance carbon material can be obtained.

[0028] (2) The zirconium-carbon integrated adsorbent is prepared by a double-ligand zirconium-carbon composite. First, zirconium chloride, 2-amino terephthalic acid, and 2,5-dihydroxy terephthalic acid are dissolved in N,N-dimethylformamide (DMF), and the molar ratio of zirconium chloride, 2-amino terephthalic acid, 2,5-dihydroxy terephthalic acid, and DMF is 1:1:0.1:159. The solution is stirred on a magnetic stirrer. Then, 1 mol / L glacial acetic acid is added, and the solution is stirred again. The solution is then poured into a hydrothermal reactor with a polytetrafluoroethylene lining for a solvothermal reaction. The molar ratio of glacial acetic acid to zirconium chloride is 1:14. After the solvothermal reaction is completed, the hydrothermal reactor is cooled to 20°C. The supernatant is filtered, and the obtained solid phase is washed with DMF and methanol alternately for three times. The solid sample obtained after centrifugation at a speed of 5000 r / min for 5 minutes is placed in a vacuum drying oven for vacuum drying to obtain a double-ligand zirconium-based MOF. Finally, the prepared double-ligand zirconium-based MOF material and the high-performance carbon material prepared in step (1) are placed in a DMF solution and stirred. The mixture is then placed in a microwave container and reacted at 120°C for 30 minutes under static conditions to obtain a zirconium-carbon integrated adsorbent with a double ligand.

[0029] It should be understood that the prepared zirconium-carbon integrated adsorbent can be used for biogas separation and purification to obtain CH4 and CO2.

[0030] In some embodiments, biogas can also be prepared based on the hydrothermal liquid of kitchen waste, and then the prepared biogas can be separated and purified using the zirconium-carbon integrated adsorbent to obtain CH4 and CO2.

[0031] Further, biogas can be prepared based on the hydrothermal liquid of kitchen waste. The kitchen waste is placed in a hydrothermal reactor and subjected to hydrothermal reaction by the same method as in step (1). After the hydrothermal reaction is completed, the reactor is cooled to 20°C. Then, a vacuum filtration device is used for filtration to separate the solid and liquid phases. The liquid phase after the solid-liquid separation is subjected to oil-water separation in a separatory funnel device. The liquid phase after the oil-water separation is used as fuel for combustion. The organic waste liquid after the oil-water separation is pumped into a mesophilic fermentation device for fermentation to obtain biogas. The biogas can be sent to a separation device, and then subjected to gas separation and purification using the zirconium-carbon integrated adsorbent.

[0032] It should be understood that the zirconium-carbon integrated adsorbent can also be used for separation and purification of biogas obtained by other methods.

[0033] Further, the zirconium-carbon integrated adsorbent is used for separating and purifying the biogas: the zirconium-carbon integrated adsorbent is placed in a separation device, the biogas is sent into the separation device, and during the adsorption of the zirconium-carbon integrated adsorbent, the tail gas is collected every fixed time for GC-TCD detection to obtain the gas content, the adsorption selectivity of CO2 / CH4 is calculated through a multi-component gas adsorption selectivity formula, the zirconium-carbon integrated adsorbent used for adsorbing the gas is subjected to desorption treatment in a way of temperature increase and pressure reduction, the zirconium-carbon integrated adsorbent is repeatedly used for separating and purifying the gas desorbed, and until high-purity CH4 and CO2 are separated and purified, wherein the purity of the high-purity methane and carbon dioxide is greater than or equal to 99.9%. The CH4 and CO2 are collected respectively, the collected high-purity CO2 is used for controlling the activation atmosphere in the hydrothermal coke physical activation process, so that the adsorbent has a more optimal pore structure, and the collected CH4 can be used in the fields of direct combustion, high-value power generation, automobile fuel and the like due to the high purity.

[0034] It should be understood that, since the zirconium-carbon integrated adsorbent has good regeneration performance, the zirconium-carbon integrated adsorbent is repeatedly used for separating and purifying the gas desorbed, and until high-purity CH4 and CO2 can be separated and purified.

[0035] Further, the multi-component gas adsorption selectivity formula is as follows:

[0036]

[0037] wherein S is the adsorption selectivity of CO2 / CH4; q CO2 and q CH4 are the adsorption amounts of carbon dioxide and methane respectively; p CO2 and p CH4 represent the partial pressures of carbon dioxide and methane respectively.

[0038] To sum up, the high-performance carbon material and the dual-ligand zirconium-based MOF can share advantages after being compounded to prepare the zirconium-carbon integrated adsorbent, so that the stability of the adsorbent is enhanced, and the biogas separation and purification capacity of the adsorbent is improved; the organic waste liquid separated from the hydrothermal liquid of the kitchen waste can be used for fermentation to produce biogas, and the oil phase separated can be used as fuel; the biogas can be separated, the high-purity CO2 obtained after the biogas separation can be recycled for the physical activation process of the carbon material, and the high-purity CH4 obtained after the biogas separation can be applied in a wider range of scenarios.

[0039] The preparation method of the zirconium-carbon integrated adsorbent for efficiently purifying biogas according to the embodiments will be described in detail below, and the purposes and effects of the present application will become more apparent.

[0040] Example 1

[0041] (1) Preparation of high-performance carbon materials based on kitchen waste: First, 10 g of kitchen waste was mixed with 100 ml of deionized water and placed in a hydrothermal reactor. The hydrothermal reaction was carried out at a temperature of 280°C for 60 minutes. After the reaction was completed, the hydrothermal reactor was cooled to 20°C by circulating cooling water. Then the solid-liquid mixture was separated by vacuum filtration device with 4.5 μm filter paper. The solid phase obtained by solid-liquid separation was dried in a drying oven at 100°C for 8 hours and then ground to obtain powdered hydrothermal coke. The hydrothermal coke was mixed with chemical activator KHCO3 by impregnation method with a mass ratio of 1:2, and 20 ml of deionized water was added and mixed thoroughly. Then it was placed in a 100°C drying oven and dried for 4 hours to obtain a solid powder. Next, the solid powder was placed in a tube furnace, and N2 was introduced to ensure that the air in the tube furnace was completely evacuated. The activation temperature was set to 700°C, and the activation time was 7 hours. N2 was continuously introduced until the activation reaction was completed. Then, after the tube furnace was cooled, the obtained powder was collected and washed with 1 mol / L hydrochloric acid until no bubbles were produced. Then it was washed with deionized water until the filtrate was neutral. Vacuum filtration device was used for filtration. After the filtration process was completed, it was placed in a drying oven for drying. The dried solid powder was further ground and placed in a high-purity CO2 atmosphere for physical activation, where the purity of high-purity CO2 was greater than or equal to 99.9%. High-performance carbon materials were obtained. By chemical and physical activation methods, the hydrothermal coke obtained based on kitchen waste can be activated to obtain high-performance carbon materials.

[0042] (2) Preparation of zirconium-carbon integrated adsorbent by double-ligand zirconium-carbon complex: First, 5 mmol of zirconium chloride, 5 mmol of 2-amino terephthalic acid, and 0.5 mmol of 2,5-dihydroxy terephthalic acid were dissolved in 60 ml of DMF and placed on a magnetic stirrer with a stirring speed of 500 r / min for 40 minutes. Then 4 ml of concentrated glacial acetic acid with a concentration of 1 mol / L was added, and the mixture was stirred again for 20 minutes. Then it was poured into a 100 mL hydrothermal reactor with a polytetrafluoroethylene liner and heated at 120°C for 24 hours for solvothermal reaction. After the solvothermal reaction was completed, the hydrothermal reactor was cooled to 20°C, and the supernatant was filtered. The obtained solid phase was washed with DMF and methanol alternately three times, and then centrifuged at a speed of 5000 r / min for 5 minutes. The solid sample obtained by removing the liquid phase was placed in a 150°C vacuum drying oven for 10 hours to obtain a double-ligand zirconium-based MOF, denoted as U66B-NH2-10%(OH)2. Finally, 1 g of the prepared double-ligand zirconium-based MOF material and 0.1 g of the high-performance carbon material prepared in step (1) were placed in a DMF solution and stirred for 30 minutes. Then it was placed in a microwave container and reacted at 120°C for 30 minutes under static conditions to obtain a zirconium-carbon integrated adsorbent U66B-NH2-10%(OH)2#C with double ligands.

[0043] (3) Preparation of biogas based on hydrothermal liquid of kitchen waste: the same method as in step (1) is used to place kitchen waste in a hydrothermal reactor for hydrothermal reaction. After the hydrothermal reaction is completed, it is cooled to 20°C, and then vacuum filtration is used to separate the solid and liquid. The liquid phase after solid-liquid separation enters a separatory funnel device for oil-water separation. The liquid phase after oil-water separation is used as fuel for combustion. The organic waste liquid after oil-water separation is pumped into a medium temperature fermentation device for fermentation, and biogas is obtained after fermentation.

[0044] (4) Separation and purification of biogas using zirconium-carbon integrated adsorbent: 0.5g of U66B-NH2-10% (OH)2#C is placed in a separation device, and biogas is sent into the separation device. During the adsorption process of the zirconium-carbon integrated adsorbent, the tail gas is collected every five minutes for GC-TCD detection. The adsorption selectivity of CO2 / CH4 is calculated by a multi-gas adsorption selectivity formula. The zirconium-carbon integrated adsorbent that has been used to adsorb gas is desorbed. Due to the good regeneration performance of the zirconium-carbon integrated adsorbent, it can be used again to separate and purify the gas desorbed. Until high-purity CH4 and CO2 can be separated and purified. CH4 and CO2 are collected separately. The collected high-purity CO2 is used to control the activation atmosphere in the hydrothermal coke physical activation process, so that the zirconium-carbon integrated adsorbent has a more optimal pore structure. The collected CH4 can be used for direct combustion, high-value power generation, and automobile fuel fields due to its high purity.

[0045] Example 2

[0046] (1) Preparation of high-performance carbon material based on kitchen waste: First, 10 g of kitchen waste is mixed with 100 ml of deionized water and placed in a hydrothermal reactor, and hydrothermal reaction is carried out at a temperature of 240°C for 60 min. After the reaction is completed, the hydrothermal reactor is cooled to 20°C by circulating cooling water. Then the solid-liquid mixture obtained is separated by vacuum filtration device with 4.5 μm filter paper, and the solid phase obtained by solid-liquid separation is dried at 100°C for 8 h and then ground to obtain powdered hydrothermal coke. Then the hydrothermal coke is mixed with the chemical activator KHCO3 by impregnation method at a mass ratio of 1:2, 20 ml of deionized water is added and mixed thoroughly, and then placed in a 100°C drying oven for 4 h to obtain a solid powder. Next, the solid powder is placed in a tube furnace, N2 is introduced to ensure that the air in the tube furnace is completely exhausted, the activation temperature is set to 700°C, the activation time is 7 h, and N2 is continuously introduced until the activation reaction is completed. Then, after the tube furnace is cooled, the obtained powder is collected and washed with 1 mol / L hydrochloric acid until no bubbles are generated, then washed with deionized water until the filtrate is neutral, and then filtered using a vacuum filtration device. After the filtration process is completed, it is placed in a drying oven for drying, and the solid powder obtained after drying is further ground and placed in a high-purity CO2 atmosphere for physical activation, wherein the purity of high-purity CO2 is greater than or equal to 99.9%, to obtain a high-performance carbon material. By synergistic activation of hydrothermal coke based on kitchen waste through chemical and physical activation methods, a high-performance carbon material can be obtained.

[0047] (2) Preparation of zirconium-carbon integrated adsorbent by double-ligand zirconium-carbon complex: First, 10 mmol of zirconium chloride, 10 mmol of 2-amino terephthalic acid, and 1 mmol of 2,5-dihydroxy terephthalic acid are dissolved in 120 ml of DMF and placed on a magnetic stirrer for stirring at a speed of 500 r / min for 40 minutes. Then 8 ml of concentrated glacial acetic acid with a concentration of 1 mol / L is added, and stirring is carried out again for 20 minutes. Then pour into a 100 mL hydrothermal reactor with a polytetrafluoroethylene liner and heat at 120°C for 24 h for solvothermal reaction. After the solvothermal reaction is completed, the hydrothermal reactor is cooled to 20°C, and the supernatant is filtered. The obtained solid phase is washed with DMF and methanol alternately three times, and then centrifuged at a speed of 5000 r / min for 5 minutes using a centrifuge. The solid sample obtained by removing the liquid phase is placed in a 150°C vacuum drying oven for vacuum drying for 10 h to obtain a double-ligand zirconium-based MOF, which is denoted as U66B-NH2-10%(OH)2. Finally, 1 g of the prepared double-ligand zirconium-based MOF material and 0.1 g of the high-performance carbon material prepared in step (1) are placed in a DMF solution, stirred for 30 minutes, and then placed in a microwave container for reaction at 120°C for 30 minutes under static conditions to obtain a zirconium-carbon integrated adsorbent U66B-NH2-10%(OH)2#C with double ligands.

[0048] Example 3

[0049] (1) Preparation of high-performance carbon materials based on kitchen waste: First, 10 g of kitchen waste is mixed with 100 ml of deionized water and placed in a hydrothermal reactor. The hydrothermal reaction is carried out at a temperature of 280°C for 30 minutes. After the reaction is completed, the hydrothermal reactor is cooled to 20°C by circulating cooling water. Then, the solid-liquid mixture obtained is separated by vacuum filtration with a 4.5 μm filter paper. The solid phase obtained by solid-liquid separation is dried at 100°C for 8 hours and then ground to obtain powdered hydrothermal coke. The hydrothermal coke is then mixed with the chemical activator KHCO3 in a mass ratio of 1:2 and 20 ml of deionized water is added. After stirring, the mixture is placed in a 100°C drying oven and dried for 4 hours to obtain a solid powder. Next, the solid powder is placed in a tube furnace, and N2 is introduced to ensure that the air in the tube furnace is completely evacuated. The activation temperature is set to 800°C, and the activation time is 6 hours. N2 is continuously introduced until the activation reaction is completed. Then, after the tube furnace is cooled, the obtained powder is collected and washed with 1 mol / L hydrochloric acid until no bubbles are produced. Then, deionized water is used to wash until the filtrate is neutral. Vacuum filtration is performed using a vacuum filtration device. After the filtration process is completed, the sample is placed in a drying oven and dried. The dried solid powder is further ground and placed in a high-purity CO2 atmosphere for physical activation. The purity of the high-purity CO2 is greater than or equal to 99.9%. High-performance carbon materials are obtained. By using chemical and physical activation methods to activate hydrothermal coke based on kitchen waste, high-performance carbon materials can be obtained.

[0050] (2) Preparation of zirconium-carbon integrated adsorbent by double-ligand zirconium-carbon complex: First, 15 mmol of zirconium chloride, 15 mmol of 2-amino terephthalic acid, and 1.5 mmol of 2,5-dihydroxy terephthalic acid are dissolved in 180 ml of DMF and placed on a magnetic stirrer with a stirring speed of 500 r / min for 40 minutes. Then, 12 ml of concentrated glacial acetic acid with a concentration of 1 mol / L is added, and the mixture is stirred again for 20 minutes. Then, it is poured into a 100 mL hydrothermal reactor with a polytetrafluoroethylene liner and heated at 120°C for 24 hours for solvothermal reaction. After the solvothermal reaction is completed, the hydrothermal reactor is cooled to 20°C, and the supernatant is filtered. The obtained solid phase is washed with DMF and methanol alternately three times, and then centrifuged at a speed of 5000 r / min for 5 minutes. The solid sample obtained by removing the liquid phase is placed in a 150°C vacuum drying oven for 10 hours to obtain a double-ligand zirconium-based MOF, which is denoted as U66B-NH2-10%(OH)2. Finally, 1 g of the prepared double-ligand zirconium-based MOF material and 0.1 g of the high-performance carbon material prepared in step (1) are placed in a DMF solution and stirred for 30 minutes. Then, they are placed in a microwave container and reacted at 120°C for 30 minutes under static conditions to obtain a zirconium-carbon integrated adsorbent U66B-NH2-10%(OH)2#C with double ligands.

[0051] In summary, the high-performance carbon material of the present application and the double-ligand zirconium-based MOF can share advantages after compounding, not only enhancing the stability of the zirconium-carbon integrated adsorbent, but also improving the biogas separation and purification capacity of the zirconium-carbon integrated adsorbent; the organic waste liquid separated from the hydrothermal liquid of the kitchen waste is used for fermentation to produce biogas, and the oil phase separated can be used as fuel; the present application can separate biogas, and the high-purity CO2 obtained after biogas separation can be recycled for the physical activation process of carbon material, and the high-purity CH4 obtained after biogas separation can be applied in a wider range of scenarios.

[0052] The above description is only the preferred embodiment of the present application, although the present application has been disclosed as above with the preferred embodiment, however, it is not intended to limit the present application. Any person skilled in the art, without departing from the scope of the technical scheme of the present application, can make many possible changes and modifications to the technical scheme of the present application by using the disclosed methods and technical contents, or modify equivalent embodiments. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application, without departing from the content of the technical scheme of the present application, still belongs to the protection scope of the technical scheme of the present application.

Claims

1. A method for preparing a zirconium-carbon integrated adsorbent for efficient biogas purification, characterized in that, Includes the following steps: (1) Preparation of high-performance carbon materials based on kitchen waste: First, kitchen waste and deionized water are mixed and placed in a hydrothermal reactor. The hydrothermal reaction is carried out at a temperature of 240-280℃ for 30-60 minutes. After the hydrothermal reaction, a wall-mounted circulating cooling water is introduced to cool the hydrothermal reactor to 20℃. Then, the obtained solid-liquid mixture is separated by a vacuum filtration device. The solid phase obtained by solid-liquid separation is dried in a drying oven and then ground to obtain powdered hydrothermal coke. Then, the hydrothermal coke and chemical activator are mixed by impregnation at a mass ratio of 1:2 and deionized water is added and mixed thoroughly. The mixture is then placed in a drying oven for drying to obtain solid powder, wherein the chemical activator is carbon. Potassium hydrogen phosphate was used as the first step. The solid powder was then placed in a tube furnace, and nitrogen gas was introduced to ensure all air was purged. The activation temperature was set to 700-800℃, and the activation time was 6-7 hours. Nitrogen gas was continuously introduced until the activation reaction was complete. After the tube furnace cooled, the powder was collected and washed with 1 mol / L hydrochloric acid until no bubbles were generated. Then, it was washed with deionized water until the filtrate was neutral. Vacuum filtration was performed, and after filtration, the powder was dried in a drying oven. The dried solid powder was further ground and then placed in a high-purity carbon dioxide atmosphere for physical activation to obtain high-performance carbon materials, wherein the purity of the high-purity carbon dioxide was greater than or equal to 99.9%. (2) Preparation of integrated zirconium-carbon adsorbent via dual-ligand zirconium-carbon composite: First, zirconium chloride, 2-aminoterephthalic acid, and 2,5-dihydroxyterephthalic acid were dissolved in N,N-dimethylformamide, wherein the molar ratio of zirconium chloride, 2-aminoterephthalic acid, 2,5-dihydroxyterephthalic acid, and N,N-dimethylformamide was 1:1:0.1:159, and stirred on a magnetic stirrer; then, 1 mol / L glacial acetic acid was added, stirred again, and then poured into a hydrothermal reactor with a polytetrafluoroethylene liner for solvothermal reaction, wherein the molar ratio of glacial acetic acid to zirconium chloride was 1:14; after the solvothermal reaction was completed, the hydrothermal reactor was cooled to 20°C, the supernatant was filtered, and the obtained solid phase was subjected to N The sample was washed three times alternately with N,N-dimethylformamide and methanol, and then centrifuged at 5000 r / min for 5 minutes. The solid sample obtained after centrifugation was placed in a vacuum drying oven for vacuum drying to obtain a dual-ligand zirconium-based metal-organic framework. Finally, the prepared dual-ligand zirconium-based metal-organic framework material and the high-performance carbon material prepared in step (1) were placed in an N,N-dimethylformamide solution and stirred. The mixture was then placed in a microwave container and reacted at 120℃ for 30 minutes under static conditions to obtain a zirconium-carbon integrated adsorbent with dual ligands.

2. The method for preparing a zirconium-carbon integrated adsorbent for efficient biogas purification according to claim 1, characterized in that, Also includes: Biogas preparation based on hydrothermal liquid from kitchen waste: Kitchen waste is placed in a hydrothermal reactor for hydrothermal reaction using the same method as in step (1). After the hydrothermal reaction is completed, the mixture is cooled to 20°C and then filtered using a vacuum filtration device to separate the solid and liquid phases. The liquid phase after solid-liquid separation is fed into a separating funnel device for oil-water separation. The oil phase after oil-water separation is used as fuel for combustion. The organic waste liquid after oil-water separation is pumped into a medium-temperature fermentation device for fermentation. Biogas is obtained after fermentation.

3. The method for preparing the zirconium-carbon integrated adsorbent for efficient biogas purification according to claim 1, characterized in that, Also includes: The separation and purification of biogas using a zirconium-carbon integrated adsorbent: The zirconium-carbon integrated adsorbent is placed in a separation device, and biogas is fed into the separation device. During the adsorption process of the zirconium-carbon integrated adsorbent, the tail gas is collected at fixed intervals for GC-TCD detection to obtain the gas content. The adsorption selectivity of carbon dioxide / methane is calculated using the multi-element gas adsorption selectivity formula. The zirconium-carbon integrated adsorbent used for gas adsorption is desorbed by heating and depressurizing. The zirconium-carbon integrated adsorbent is reused to further separate and purify the desorbed gas until high-purity methane and carbon dioxide are obtained, with the purity of the high-purity methane and carbon dioxide being greater than or equal to 99.9%.

4. The method for preparing the zirconium-carbon integrated adsorbent for efficient biogas purification according to claim 3, characterized in that, The formula for the adsorption selectivity of the multi-component gas is expressed as follows: ； Where S represents the adsorption selectivity of carbon dioxide / methane; q CO2 q CH4 These represent the adsorption amounts of carbon dioxide and methane, respectively; p CO2 p CH4 These represent the partial pressures of carbon dioxide and methane, respectively.

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