Synthesis method and use of bifunctional materials for carbon dioxide capture and in situ conversion

Abstract

The present application relates to a synthesis method and use of a bifunctional material for carbon dioxide capture and in-situ conversion. The present application uses calcium-containing solid waste and waste circuit boards as raw materials, uses organic acid to extract copper metal, and modifies calcium-based functional materials in-situ to alleviate the sintering problem of calcium-based materials, so that ICCU bifunctional materials can be synthesized at low cost. Therefore, the synthesis method of the present application not only provides a new idea for the resource utilization of calcium-containing solid waste and PCB board and the improvement of carbon emission reduction benefit, but also reduces the cost of the existing ICCU bifunctional material.

Description

Technical Field

[0001] This invention belongs to the field of carbon dioxide capture and conversion technology, and provides a method for synthesizing bifunctional materials for carbon dioxide capture and in-situ conversion using waste, as well as the uses of the bifunctional materials. Background Technology

[0002] Carbon capture, utilization and storage (CCUS) has always been a focus of international attention and is considered one of the most promising and effective means of emission reduction.

[0003] In the carbon capture stage of CCUS technology, calcium-based absorbent cyclic CO2 capture technology has become a research hotspot due to its advantages such as readily available raw materials, large theoretical capture capacity, and fast capture rate. Absorbents developed based on traditional calcium recycling have also become a focus of research. Currently, the most significant factor hindering the large-scale application of calcium-based absorbent cyclic CO2 capture technology is the decline in CO2 capture performance of the high-temperature sintered calcium-based absorbent as the recycling reaction progresses. Current modification methods mainly include heat pretreatment and hydration reaction pretreatment, the addition of inert supports, and acidification treatment of natural calcium-containing minerals using organic acids.

[0004] Patent document 1 (CN117463343A) discloses a method for synthesizing a carbon dioxide adsorption-catalysis bifunctional material. The method involves leaching a high-calcium solid waste with a solution containing organic acid to obtain a mixture. The mixture is then filtered, and the resulting filtrate is mixed with a soluble active metal salt, a soluble metal auxiliary salt, and an acidic complexing agent to obtain a mixed solution. This mixed solution is then subjected to gelation treatment, calcination, and reduction to obtain the carbon dioxide adsorption-catalysis bifunctional material. The high-calcium solid waste is selected from at least one of steel slag, carbide slag, mineral powder slag, and desulfurization slag. The soluble active metal salt is selected from at least one of nitrates of Ru, Rh, Pt, Ni, and Co. As can be seen from the above, the active metal component in patent document 1 is not extracted from waste and cannot be considered economical.

[0005] In addition, a disruptive technology has emerged in the CCUS field in recent years: In-situ Carbon Dioxide Capture and Conversion (ICCU). The key to this technology is the use of a bifunctional material that can simultaneously capture and convert carbon dioxide in situ, achieving in-situ capture and utilization. This eliminates the costs associated with CO2 compression and transportation, and reduces the risk of CO2 leakage. Simultaneously, ICCU technology can lower the regeneration temperature of calcium-based adsorbents, alleviating the problem of material sintering. Although ICCU technology has significantly reduced costs compared to traditional CCUS technology, it still faces the challenge of excessively high costs. Summary of the Invention

[0006] The problem the invention aims to solve

[0007] To address the high cost of current ICCU technology, a method is needed to synthesize bifunctional materials at low cost by fully utilizing waste materials. Simultaneously, a technology is also needed to capture carbon dioxide using ICCU technology and synthesize carbon monoxide, a key component of syngas used in industry, in situ.

[0008] Solution for solving the problem

[0009] Calcium-containing solid waste (referred to as "calcium-containing solid waste") such as eggshells, seashells, carbide slag, snail shells, and red mud are important components of solid waste. Calcium-containing solid waste, such as eggshells, has a high proportion of organic matter and calcium, easily causing environmental pollution and breeding grounds for bacteria. Currently, the recycling rate of calcium-containing solid waste is low, with most being directly discarded, and a large-scale, industrialized treatment system has not yet been formed. Calcium-containing solid waste, such as eggshells, is mainly composed of calcium carbonate (CaCO3), accounting for about 94% of the eggshell's mass, making it an ideal raw material for calcium recycling. In addition, with the rapid pace of electronic product upgrades, the amount of printed circuit board (PCB) waste is increasing year by year, and its resource utilization also faces problems. Current waste treatment methods mainly rely on landfill and incineration, which easily lead to soil and air pollution. PCBs contain a large amount of copper, with copper content accounting for more than 90% of the metal content, making them an ideal catalyst material for reverse-flow gas shift conversion. In the resource utilization of carbon dioxide, reverse water-gas shift can yield carbon monoxide, the main component of syngas in industry, which has wide application value. Its main non-precious metal catalysts include copper, nickel, and iron. Therefore, this invention proposes a bifunctional material synthesis process based on calcium-containing solid waste and discarded circuit boards.

[0010] Furthermore, in the treatment of waste by organic acid acidification, the large amount of gas released during the calcination of the acidified organic acid salts can improve the micropore structure of the adsorbent, thereby enhancing its CO2 adsorption performance. Therefore, this invention proposes a method that combines waste recycling and adsorbent material modification processes using organic acids.

[0011] Based on the above, this invention provides a synthesis method that utilizes calcium-containing solid waste and discarded circuit boards as raw materials, extracts copper metal using organic acids, and alleviates the sintering problem of calcium-based materials by in-situ modification of calcium-based functional materials. This allows for the low-cost synthesis of ICCU bifunctional materials. Therefore, the synthesis method of this invention not only provides a new approach for the resource utilization of calcium-containing solid waste and PCB boards, but also reduces the cost of existing ICCU bifunctional materials.

[0012] Specifically, the present invention provides a method for synthesizing a bifunctional material for carbon dioxide capture and in-situ conversion, comprising the following steps:

[0013] Waste PCB board processing step S1: After calcining the waste PCB board, crush it into powder, add it to an aqueous solution of organic acid and stir, then remove the residue to obtain a copper-containing organic acid solution.

[0014] Pretreatment step S2 for calcium-containing solid waste: Calcining the calcium-containing solid waste powder to obtain calcium oxide-containing products;

[0015] Precursor preparation step S3: Mix the calcium oxide-containing product from step S2 with the copper-containing organic acid solution from step S1 and heat until dry to obtain a precursor containing copper and calcium.

[0016] Calcination step S4: The precursor obtained in step S3 is calcined and reduced to obtain the bifunctional material.

[0017] According to the synthesis method described above, the calcium-containing solid waste includes one or more of the following: waste eggshells, seashells, carbide slag, snail shells, fly ash, and red mud.

[0018] The organic acid is selected from one or more of oxalic acid, formic acid, acetic acid, propionic acid, and tartaric acid; the concentration of the aqueous solution of the organic acid is 0.01~1 mol / L, and the pH value is 1~3.

[0019] According to the synthesis method described above, in step S1, the ratio of waste PCB board powder to aqueous solution of organic acid is (0.01g~0.05g):1ml.

[0020] According to the synthesis method described above, in step S1, the calcination temperature is 800~1000℃ and the calcination time is 1~3h.

[0021] According to the synthesis method described above, in step S2, the calcium-containing solid waste powder is calcined at a temperature of 800~1000℃ for a time of 1~3h.

[0022] According to the synthesis method described above, in step S3, the ratio of calcium oxide product to copper-containing organic acid solution is (0.01g~0.05g):1ml; the heating temperature is 80~100℃.

[0023] According to the synthesis method described above, in step S4, the precursor is calcined at a temperature of 700~900℃ for a time of 1~3h.

[0024] The present invention also provides a bifunctional material obtained by the above-described synthesis method, wherein the bifunctional material comprises calcium oxide, copper-magnesium composite oxide and copper oxide.

[0025] According to the bifunctional material described above, the copper loading in the bifunctional material is 0.2wt%-0.5wt%.

[0026] The present invention further provides the use of bifunctional materials or more bifunctional materials obtained by the above-described synthesis method in carbon dioxide capture and in-situ conversion reactions to generate carbon monoxide.

[0027] The effects of the invention

[0028] The above-described technical solution of the present invention has the following beneficial effects:

[0029] 1) The synthesis method of the present invention is a low-cost bifunctional material synthesis process: This process utilizes two major wastes - copper extracted from waste circuit boards and calcium oxide recovered from calcium-containing solid waste - to form a material with adsorption and catalytic functions. It can make full use of waste resources, reduce costs, and improve carbon emission reduction benefits.

[0030] 2) Performance optimization was carried out in this invention: by adjusting the synthesis parameters such as the type of organic acid, the copper loading content, and the content of modified acid, the structure and composition of the bifunctional material were optimized, so that it has higher adsorption capacity, better stability and higher carbon monoxide conversion rate.

[0031] 3) This invention provides a novel application method for two types of solid waste: The ICCU bifunctional material synthesis process of this invention can be combined with the existing waste PCB treatment process. After the waste PCB is incinerated, copper, magnesium, calcium and other metals are extracted by organic acid leaching for bifunctional material synthesis. The remaining insoluble precious metals can be further electrolytically refined.

[0032] 4) The method of the present invention can be produced on an industrial scale; currently, the utilization rate of calcium-containing solid waste resources is low, and the present invention explores the possibility of utilizing calcium-containing solid waste. Attached Figure Description

[0033] Figure 1 The synthesis process of the bifunctional material of the present invention is shown.

[0034] Figure 2 The crystal structure of the acid-modified calcium-based bifunctional material is shown.

[0035] Figure 3 The cyclic carbon capture performance of the modified bifunctional material is shown.

[0036] Figure 4 The carbon capture and in-situ conversion (ICCU) cycle carbon capture performance of the modified bifunctional material is shown.

[0037] Figure 5 The carbon capture and in-situ conversion (ICCU) cycle carbon conversion performance of the modified bifunctional material is shown.

[0038] Figure 6The carbon capture and in-situ conversion (ICCU) cycle CO production performance of the modified bifunctional material is demonstrated. Detailed Implementation

[0039] The following describes embodiments of the present invention, but the invention is not limited thereto. The present invention is not limited to the configurations described below; various modifications can be made within the scope of the claims. Embodiments and examples obtained by appropriately combining the disclosed technical means in different embodiments and examples are also included within the technical scope of the present invention. Furthermore, all documents described in this specification are incorporated herein by reference.

[0040] Unless otherwise defined, the technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0041] In this specification, the range of values ​​referred to as "value A to value B" refers to the range including the endpoint values ​​A and B.

[0042] Unless otherwise required in this application, throughout the specification and the claims, the word "comprising" shall be interpreted in an open-ended, inclusive sense, meaning "including but not limited to".

[0043] Unless otherwise stated, in this instruction manual, "more" in "multiple", "multi-variety", "multiple", etc., means a value of 2 or more.

[0044] In this specification, the terms "substantially," "largely," or "truly" mean that the error is less than 5%, or less than 3%, or less than 1% compared to the relevant perfect or theoretical standard.

[0045] In this specification, the word "may" has two meanings: to perform a certain process and not to perform a certain process.

[0046] In this specification, "optional" or "optionally" means that the event or situation described below may or may not occur, and the description includes both the scenario in which the event occurs and the scenario in which the event does not occur.

[0047] In this instruction manual, if terms such as "room temperature" or "normal temperature" appear, the temperature is generally 25℃±2℃.

[0048] The "calcium-based material" mentioned in this invention mainly refers to calcium oxide, and may also contain a small amount of calcium carbonate.

[0049] This invention addresses the issue of high costs associated with current ICCU technology by providing a low-cost method for synthesizing bifunctional materials using waste as raw materials, while also exploring the feasibility of novel waste recycling methods.

[0050] Specifically, the synthesis method of the present invention includes the following steps:

[0051] Waste PCB board processing step S1: After calcining the waste PCB board, crush it into powder, add it to an aqueous solution of organic acid and stir, then remove the residue to obtain a copper-containing organic acid solution.

[0052] Pretreatment step S2 for calcium-containing solid waste: Calcining the calcium-containing solid waste powder to obtain calcium oxide-containing products;

[0053] Precursor preparation step S3: Mix the calcium oxide-containing product from step S2 with the copper-containing organic acid solution from step S1 and heat until dry to obtain a precursor containing copper and calcium.

[0054] Calcination step S4: The precursor obtained in step S3 is calcined and reduced to obtain the bifunctional material.

[0055] Figure 1 The diagram schematically illustrates the synthesis process of the bifunctional material of the present invention. Specifically, the pyrolysis residue of the waste PCB board ( Figure 1 The pyrolysis residue of PCB board solid waste is used to recover metallic Cu through acid leaching, yielding a copper-containing organic acid solution. On the other hand, calcium-containing solid waste is pretreated by calcination to obtain a calcium oxide-containing product. Then, the copper-containing organic acid solution is mixed with the calcium oxide-containing product to modify and load the calcium-based material with metal, obtaining a precursor containing both copper and calcium. The precursor is calcined to obtain a bifunctional material.

[0056] The following provides a detailed explanation of each step.

[0057] Step S1

[0058] In the synthesis method of this invention, waste PCB boards are first calcined, and then pulverized to obtain waste PCB board powder (hereinafter referred to as "PCB powder"). The calcination temperature of the PCB board can be 800~1000℃, and the calcination time can be 1~3h. If the calcination temperature is too low, the organic matter in the PCB board cannot be completely removed.

[0059] This invention employs an organic acid leaching method to extract copper from calcined PCB boards. Specifically, the calcined PCB powder is added to an aqueous solution of organic acid, stirred, and after sufficient reaction, filtered to remove residue, thereby obtaining a copper-containing organic acid solution. This copper-containing organic acid solution will be used for the modification of calcium-based materials and the synthesis of bifunctional materials.

[0060] In this invention, the organic acid can be selected from one or more of oxalic acid, formic acid, acetic acid, propionic acid, and tartaric acid. The concentration of the aqueous solution of the organic acid can be 0.01~1 mol / L, and the pH value can be 1~3. This is because too low an acid concentration will not have a good modification effect on bifunctional materials; too high an acid concentration will increase the cost.

[0061] The ratio of waste PCB powder to an aqueous solution of organic acid can be (0.01g~0.05g):1ml. Therefore, 1-5g of PCB powder can be added to every 100ml of organic acid solution. After adding the PCB powder, stir for a certain period of time, and then filter to remove insoluble impurities. The stirring time can be 2~5 hours.

[0062] In step S1, in order to adjust the copper ion concentration, an appropriate amount of organic acid aqueous solution of the same concentration can be optionally added to the copper-containing organic acid solution after removing the residue, thereby diluting the copper ions to a suitable concentration.

[0063] In actual industrial production, the waste PCB board treatment and acid leaching process can be combined with existing PCB processing technologies such as heat treatment or incineration, and a waste gas treatment device can be added. Furthermore, after extracting large amounts of elements such as copper, magnesium, and calcium using the acid leaching method of this invention, the remaining precious metals can be further refined by electrolysis. The advantage of the PCB board treatment method of this invention lies in combining the acid leaching process with the organic acid modification process of bifunctional materials, resulting in simple steps, reduced costs, and compatibility with existing mature technologies.

[0064] Step S2

[0065] In this invention, the calcium-containing solid waste mentioned in step S2 may include one or more of the following: waste eggshells, seashells, carbide slag, snail shells, fly ash, and red mud. When the calcium-containing solid waste is eggshells, seashells, or snail shells, its main component is calcium carbonate; when the calcium-containing solid waste is carbide slag, fly ash, or red mud, its main component is calcium oxide.

[0066] When the calcium-containing solid waste is shells, carbide slag, snail shells or red mud, it can be directly calcined after being crushed into powder to obtain calcium oxide products.

[0067] When the calcium-containing solid waste is discarded eggshells, in order to prevent the organic matter in the eggshell membrane from participating in the reaction, it is necessary to separate the powder from the eggshell membrane.

[0068] For example, eggshells can be crushed and soaked in water to form powder. The turbid liquid is stirred thoroughly and allowed to stand for 10-30 minutes. The membrane on the top of the liquid is separated from the eggshell at the bottom. The eggshell powder is then dried and calcined in a muffle furnace to obtain a calcium oxide product made from eggshells.

[0069] In step S2, the calcination temperature of the calcium-containing solid waste powder can be 800~1000℃, and the calcination time can be 1~3h. The reason is that if the calcination temperature is too low or the calcination time is too short, the calcium carbonate will not be completely decomposed; while if the calcination time is too long, the material is prone to sintering.

[0070] Step S3

[0071] In step S3, the calcium oxide-containing product obtained in step S2 is mixed with the copper-containing organic acid solution from step S1, and the mixture is stirred and heated in an oil bath until completely evaporated to obtain a copper-containing organic calcium precursor. In step S3, organic acids are used to modify the calcium oxide.

[0072] The heating temperature in step S3 can be 80~100℃. The ratio of the calcium oxide-containing product to the acid solution used for modification is (0.01g~0.05g):1ml. This is because materials with a high modified acid content have better carbon capture performance, while excessively high modified acid content will increase the cost of the material.

[0073] Step S4

[0074] The copper-containing organic calcium precursor obtained in step S3 was calcined and reduced in a muffle furnace to obtain a bifunctional material.

[0075] In this invention, the precursor is calcined at a temperature of 700~900℃ for 1~3 hours. This is because if the calcination temperature is too low, the material cannot be completely decomposed; if the calcination temperature is too high, the material will sinter.

[0076] The reduction described above can be carried out in a pure hydrogen atmosphere at 800~1000℃. The reduction temperature can be, for example, 850℃, 900℃, 950℃, etc.

[0077] The working principle of this invention is based on the recycling of waste circuit boards and calcium-containing solid waste, realizing a low-cost method for preparing in-situ carbon dioxide capture and conversion (ICCU) bifunctional materials. The specific working principle is as follows:

[0078] Copper extraction from waste circuit boards: After heat treatment, the copper in the waste circuit boards is oxidized to copper oxide, which is then leached with an organic acid solution. The reaction with the copper oxide produces a copper-containing acid solution. This organic acid solution not only recovers valuable metal resources but also plays a role in modifying calcium oxide in subsequent steps.

[0079] Calcium-based materials for recycling calcium-containing solid waste: As a major component of calcium recycling absorbents, calcium-based materials have a high CO2 adsorption capacity.

[0080] Performance Improvement through Modification: Organic acids are not only used for copper extraction from waste circuit boards, but also for the modification of calcium oxide. Modified calcium oxide exhibits better stability, solving the sintering problem inherent in traditional calcium recycling techniques and improving the cycle life of the collected materials.

[0081] As can be seen from the above, the present invention utilizes copper extracted from waste circuit boards and calcium-based materials recovered from calcium-containing solid waste to form materials with adsorption and catalytic functions, making full use of waste gas resources, reducing costs, and improving carbon emission reduction benefits.

[0082] Furthermore, the present invention also provides bifunctional materials obtained by the above-described synthesis method, wherein the bifunctional materials include calcium oxide, copper-magnesium composite oxide and copper oxide.

[0083] The copper loading in the bifunctional material of this invention is 0.2wt%-0.5wt%. This is because experiments showed that the material with a copper content of 0.2wt% maintained a stable carbon capture of approximately 9 mmol / g after ten ICCU cycles, while the material with a copper content of 0.5wt% maintained a stable carbon capture of approximately 6 mmol / g after ten ICCU cycles. Furthermore, both materials exhibited a conversion rate of approximately 80%, demonstrating excellent overall performance. Too low a copper concentration would result in poor catalytic effect and low conversion rate; too high a copper concentration would lead to sintering problems and poor carbon capture.

[0084] In addition, the present invention also provides the use of bifunctional materials obtained by the above-described synthesis method or the above-described bifunctional materials in carbon dioxide capture and in-situ conversion reactions to generate carbon monoxide.

[0085] Specifically, the bifunctional material of this invention was granulated and sieved, and samples with a particle size of 0.35-0.45 mm were placed in a fixed reaction bed at atmospheric pressure. Air in the reaction system was removed using nitrogen, and the samples were reduced under pure hydrogen conditions. Then, a cycle was initiated: each cycle alternately introduced a mixture of carbon dioxide and nitrogen followed by pure hydrogen to simulate the carbon dioxide capture and in-situ conversion process. The results showed that the bifunctional material of this invention exhibited excellent carbon dioxide capture capacity, as well as excellent conversion rate and selectivity, in the ICCU cycle.

[0086] Example

[0087] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0088] Example 1

[0089] according to Figure 1 The technical principle of the present invention is used to prepare ICCU bifunctional materials, as detailed below:

[0090] (1) Take a conventional PCB board and calcine it at 900℃ for 2 hours in a muffle furnace, then grind and pulverize it into powder. Take 0.18g of solid oxalic acid and dissolve it in 100ml of deionized water. After it is completely dissolved, add 2g of PCB powder and stir it at 200 rpm for 4 hours on a magnetic stirrer. Then filter it to obtain a copper-containing acid solution.

[0091] (2) Take conventionally discarded eggshells, wash and grind them, add water to rinse and let stand to remove the biofilm, after the shell membrane is separated, take the membrane-free eggshells at the bottom of the solution, dry them, and calcine them in a muffle furnace at 900℃ for 2 hours.

[0092] (3) Add 2.26g of the calcined eggshell to 100ml of acid solution in step (1), heat in an oil bath at 90℃ while stirring at 200 rpm until dry.

[0093] (4) The solid after evaporation was calcined in a muffle furnace at 800°C for 2 hours and then reduced at 900°C in a pure hydrogen atmosphere to obtain ICCU bifunctional material.

[0094] Example 2-1

[0095] The catalyst synthesis process is basically the same as in Example 1, except that the acid solution preparation method and the amount of eggshell added are changed. In this example, step (1) is as follows: 40 ml of pure acetic acid is added to 50 ml of deionized water and dissolved evenly, then 2 g of PCB powder is added and stirred at 200 rpm for 4 h on a magnetic stirrer. The mixture is then filtered to obtain the original acid solution. 165 ml of acetic acid of the same concentration (50% acetic acid by volume) is added to the original acid solution to dilute it and obtain 265 ml of acid solution.

[0096] In this embodiment, step (3) involves adding 6g of the calcined eggshell to 265ml of the obtained acid solution, while keeping the rest the same.

[0097] Example 2-2

[0098] The catalyst synthesis process is basically the same as in Example 2, except that the mass of eggshell added in step (3) is changed to 12g of calcined eggshell added to the 265ml acid solution obtained, while the rest remains the same.

[0099] Example 3-1

[0100] The catalyst synthesis process is basically the same as in Example 1, except that the acid solution preparation method and the amount of eggshell added are changed. In this example, step (1) is as follows: 2g of oxalic acid is added to 100ml of deionized water and dissolved evenly, then 3g of PCB powder is added and stirred at 200 rpm for 12 hours on a magnetic stirrer. The mixture is then filtered to obtain the original acid solution. 50ml of oxalic acid of the same concentration is added to the original acid solution to dilute it and obtain 150ml of acid solution.

[0101] In step (3) of this embodiment: 2g of the calcined eggshell is added to 150ml of the obtained acid solution, while the rest remains the same. In this embodiment, the Cu loading is 0.8wt% relative to the mass of the obtained ICCU bifunctional material.

[0102] Example 3-2

[0103] The catalyst synthesis process is basically the same as in Example 1, except that the acid solution preparation method and the amount of eggshell added are changed. In this example, step (1) is as follows: 2g of oxalic acid is added to 100ml of deionized water and dissolved evenly, then 3g of PCB powder is added and stirred at 200 rpm for 12 hours on a magnetic stirrer. The mixture is then filtered to obtain the original acid solution. 62.5ml of the original acid solution is diluted with 87.5ml of oxalic acid of the same concentration to obtain 150ml of acid solution.

[0104] In step (3) of this embodiment: 2g of calcined eggshell is added to 150ml of the obtained acid solution, while the rest remains the same. In this embodiment, the Cu loading is 0.5wt% relative to the mass of the obtained ICCU bifunctional material.

[0105] Example 3-3

[0106] The catalyst synthesis process is basically the same as in Example 1, except that the acid solution preparation method and the amount of eggshell added are changed. In this example, step (1) is as follows: 2g of oxalic acid is added to 100ml of deionized water and dissolved evenly, then 3g of PCB powder is added and stirred at 200 rpm for 12 hours on a magnetic stirrer. The mixture is then filtered to obtain the original acid solution. 25ml of the original acid solution is diluted with 125ml of oxalic acid of the same concentration to obtain 150ml of acid solution.

[0107] In step (3) of this embodiment: 2g of the calcined eggshell is added to 150ml of the obtained acid solution, while the rest remains the same. In this embodiment, the Cu loading is 0.2wt% relative to the mass of the obtained ICCU bifunctional material.

[0108] Example 4

[0109] The catalyst synthesis process is basically the same as in Example 1, except that the acid solution preparation method and the amount of eggshell added are changed. In this example, step (1) is as follows: 5g of oxalic acid is added to 200ml of deionized water and dissolved evenly, then 7g of PCB powder is added, and the mixture is stirred at 200 rpm for 12 hours on a magnetic stirrer. The mixture is then filtered to obtain the modified acid solution.

[0110] XRD characterization of bifunctional materials

[0111] Example 4 was selected for XRD characterization, and the results are shown in... Figure 2 In the study, it can be observed that the bifunctional materials are mainly calcium oxide, copper-magnesium composite oxide, and some copper oxide.

[0112] Application examples

[0113] Carbon capture performance testing of bifunctional materials

[0114] Three bifunctional materials prepared in Example 3 were selected, with pure eggshells as a control. Their carbon capture capacity was tested by thermogravimetric analysis. The reaction conditions were: carbonation at 650°C under a 15% V / v CO2 atmosphere, followed by calcination at 900°C under an 80% V / v CO2 atmosphere, for 25 cycles. The results are as follows: Figure 3 As shown.

[0115] Depend on Figure 3 As shown, the materials from Examples 3-2 and 3-3 (copper content 0.5wt% and 0.2wt%) with lower Cu concentrations exhibited better carbon capture, while the material from Example 3-1 with a higher copper content showed poor carbon capture ability on thermogravimetric analysis, similar to the original eggshell carbon capture performance. This is presumably because copper has a lower Taman temperature, and higher concentrations lead to sintering of the material. The two groups with lower Cu concentrations, Examples 3-2 and 3-3, showed little difference in carbon capture ability on thermogravimetric analysis.

[0116] Testing of ICCU Cyclic Carbon Capture Capacity and Catalytic Performance of Bifunctional Materials

[0117] Three bifunctional materials prepared in Example 3 were used to simulate the ICCU process on a fixed reaction bed at atmospheric pressure to test carbon capture capacity and calculate conversion rate and CO selectivity. Each cycle began with a carbon dioxide and nitrogen mixture (CO2:N2=1:9) at 650°C for 0.5 h at a flow rate of 50 ml / min, followed by a pure hydrogen gas flow at 650°C for 0.5 h. The results are as follows: Figures 4-6 As shown.

[0118] Depend on Figure 4 It can be seen that in Examples 3-3, the material with a Cu mass fraction of 0.2% exhibits the highest carbon capture amount per cycle and demonstrates the best carbon capture capability in the ICCU cycle; Figure 5 and Figure 6It can be seen that the material with a Cu mass fraction of 0.2% also exhibits excellent conversion rate and selectivity in the ICCU cycle. Taking all factors into consideration, the material modified with oxalic acid and a Cu mass fraction of 0.2% shows superior performance.

[0119] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method for synthesizing a bifunctional material for carbon dioxide capture and in-situ conversion, comprising the following steps: Waste PCB board processing step S1: After calcining the waste PCB board, crush it into powder, add it to an aqueous solution of organic acid and stir, then remove the residue to obtain a copper-containing organic acid solution. Pretreatment step S2 for calcium-containing solid waste: calcining the calcium-containing solid waste powder to obtain calcium oxide-containing products; the calcium-containing solid waste includes one or more of the following: waste eggshells, seashells, carbide slag, snail shells, fly ash, and red mud; Precursor preparation step S3: Mix the calcium oxide-containing product from step S2 with the copper-containing organic acid solution from step S1 and heat until dry to obtain a precursor containing copper and calcium. Calcination step S4: The precursor obtained in step S3 is calcined and reduced to obtain the bifunctional material; The bifunctional material includes calcium oxide, copper-magnesium composite oxide, and copper oxide; The copper loading in the bifunctional material is 0.2wt%-0.5wt%.

2. The synthesis method according to claim 1, wherein the organic acid is selected from one or more of oxalic acid, formic acid, acetic acid, propionic acid, and tartaric acid; the concentration of the aqueous solution of the organic acid is 0.01~1 mol / L, and the pH value is 1~3.

3. The synthesis method according to claim 1 or 2, wherein in step S1, the ratio of waste PCB board powder to aqueous solution of organic acid is (0.01g~0.05g):1ml.

4. The synthesis method according to claim 1 or 2, wherein in step S1, the calcination temperature is 800~1000℃ and the calcination time is 1~3h.

5. The synthesis method according to claim 1 or 2, wherein in step S2, the calcium-containing solid waste powder is calcined at a temperature of 800~1000℃ for a time of 1~3h.

6. The synthesis method according to claim 1 or 2, wherein in step S3, the ratio of the calcium oxide product to the copper-containing organic acid solution is (0.01g~0.05g):1ml; and the heating temperature is 80~100℃.

7. The synthesis method according to claim 1 or 2, wherein in step S4, the precursor is calcined at a temperature of 700~900℃ for a time of 1~3h.

8. A bifunctional material obtained by the synthesis method according to any one of claims 1-7, wherein the bifunctional material comprises calcium oxide, copper-magnesium composite oxide and copper oxide.

9. Use of a bifunctional material obtained by the synthesis method according to any one of claims 1-7 or the bifunctional material according to claim 8 in the generation of carbon monoxide through carbon dioxide capture and in-situ conversion reaction.

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