Hydrotalcite-like adsorbent prepared from blast furnace slag and application of hydrotalcite-like adsorbent in CO2 adsorption

Abstract

The invention discloses a hydrotalcite-like adsorbent prepared from blast furnace slag and application of the hydrotalcite-like adsorbent in CO2 adsorption. The hydrotalcite-like adsorbent is prepared by the following steps: crushing the blast furnace slag to obtain blast furnace slag particles; carrying out acid dissolution treatment on the blast furnace slag particles, and filtering to obtain filtrate; mixing the filtrate with an alkali source, and adjusting the pH value to be alkaline to obtain a turbid liquid; carrying out hydrothermal reaction on the turbid liquid, filtering, washing and drying to obtain an adsorbent; the content of Mg < 2 + > in the filtrate is 0.0020 to 0.027 mol / L; the content of Ca < 2 + > in the filtrate is 0.0018 to 0.012 mol / L in the filtrate. The filtrate obtained after acid dissolution of blast furnace slag particles is adopted as the raw material, and the ion content of the molecular sieve is adjusted by controlling the metal ion content in the filtrate, so that the obtained molecular sieve has a very good effect in CO2 adsorption.

Description

Technical Field

[0001] This application relates to a hydrotalcite-like adsorbent prepared from blast furnace slag and its application in CO2 adsorption. Background Technology

[0002] Blast furnace slag is a solid waste produced during the blast furnace ironmaking process. Its main components are CaO, SiO2, MgO, and Al2O3. Due to limitations in its processing technology, these methods still pose certain environmental risks during resource utilization and fail to fundamentally solve the environmental and resource problems caused by blast furnace slag. Therefore, exploring high-value-added utilization methods for blast furnace slag is essential.

[0003] With the acceleration of industrialization, the emission of the greenhouse gas carbon dioxide has been rising continuously, becoming one of the main causes of global warming. Excessive carbon dioxide emissions have led to a continuous rise in global temperatures, triggering a series of serious environmental problems such as frequent extreme weather events and rising sea levels, posing enormous challenges to natural ecosystems and human society. Therefore, the research and development of carbon dioxide emission reduction and efficient capture technologies is urgently needed and has extremely important strategic significance for addressing climate change and achieving sustainable development.

[0004] Among numerous carbon dioxide adsorption materials, hydrotalcite-like oxides (TLOs) stand out due to their unique structure and superior performance. TTLs are a type of metal hydroxide with a layered structure. The layers are primarily composed of positively charged metal hydroxides, while the interlayers are filled with negatively charged anions and water molecules. This unique structure endows TTLs with exchangeable anions between the layers, while the capacity to accommodate metal cations gives them a strong adsorption capacity. They can effectively adsorb various gas molecules, including the greenhouse gas carbon dioxide, demonstrating promising application prospects and offering a potentially efficient and feasible solution for carbon dioxide emission reduction and capture. Summary of the Invention

[0005] To address the aforementioned problems, this application proposes a hydrotalcite-like adsorbent prepared from blast furnace slag, comprising the following steps:

[0006] Blast furnace slag is crushed to obtain blast furnace slag particles;

[0007] The blast furnace slag particles are acid-dissolved and then filtered to obtain the filtrate.

[0008] The filtrate is mixed with an alkaline source, and the pH is adjusted to alkaline to obtain a suspension.

[0009] The suspension was subjected to a hydrothermal reaction, followed by filtration, washing, and drying to obtain the adsorbent.

[0010] Mg in the filtrate 2+The concentration in the filtrate is 0.0020-0.027 mol / L;

[0011] The Ca in the filtrate 2+ The concentration in the filtrate is 0.0018-0.012 mol / L. This application uses the filtrate after acid dissolution of blast furnace slag particles as raw material. By controlling the metal ion content in the filtrate, the ion content of the molecular sieve is adjusted, resulting in a molecular sieve with excellent CO2 adsorption performance.

[0012] Preferably, the blast furnace slag comprises the following components:

[0013] SiO2: 30-50wt%; CaO: 25-45wt%; Al2O3: 7-20wt%; MgO: 3-15wt%.

[0014] Preferably, the alkali source is an aqueous solution of sodium hydroxide, and the concentration of sodium hydroxide is 2-4 mol / L; the pH of the suspension is 8.5-13.5.

[0015] Preferably, the hydrothermal reaction is carried out at a temperature of 60-100°C for a duration of 12-36 hours.

[0016] The process includes pretreatment of the suspension before the hydrothermal reaction, wherein the pretreatment involves heating at 40-50°C for 1-3 hours. This application employs pretreatment to ensure the removal of Mg from the suspension. 2+ Ca 2+ Dispersion is carried out, which in turn ensures that Mg 2+ Ca 2+ Its role in the CO2 adsorption process.

[0017] Preferably, the drying temperature is 60-90℃ and the time is 6-12h.

[0018] Preferably, the pore volume of the adsorbent is 0.1-0.4 cm³. 3 / g, specific surface area of ​​50-200m² 2 / g.

[0019] Preferably, the acid dissolution treatment is performed in the following manner:

[0020] Place the blast furnace slag particles in hydrochloric acid and stir for 2-4 hours at 60-80℃.

[0021] Preferably, the concentration of the hydrochloric acid is 4-5 mol / L.

[0022] Preferably, the mass ratio of the blast furnace slag particles to hydrochloric acid is 1:10-15. This application treats blast furnace slag by acid dissolution with hydrochloric acid. By controlling the hydrochloric acid concentration, heating temperature, and heating time, the dissolution depth is controlled, thereby obtaining a filtrate with a suitable ion range. This results in a hydrotalcite-like adsorbent exhibiting better adsorption performance in CO2 adsorption.

[0023] On the other hand, this application also discloses the application of the above-mentioned hydrotalcite-like adsorbent in CO2 adsorption.

[0024] This application can bring the following beneficial effects:

[0025] 1. This application uses the filtrate after acid dissolution of blast furnace slag particles as raw material. By controlling the metal ion content in the filtrate, the ion content of the molecular sieve is adjusted, so that the obtained molecular sieve has a very good effect in CO2 adsorption.

[0026] 2. This application employs a pretreatment method to ensure the removal of Mg from the suspension. 2+ Ca 2+ Dispersion is carried out, which in turn ensures that Mg 2+ Ca 2+ Its role in the CO2 adsorption process.

[0027] 3. This application treats blast furnace slag by hydrochloric acid dissolution. By controlling the hydrochloric acid concentration, heating temperature, and heating time, the dissolution depth is controlled, thereby obtaining a filtrate with a suitable ion range. This results in the hydrotalcite-like adsorbent having a better adsorption effect in CO2 adsorption. Attached Figure Description

[0028] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0029] Figure 1 The XRD diagram is shown in the example.

[0030] Figure 2 This is a comparative XRD plot.

[0031] Figure 3 This is the SEM image of Example 1. Detailed Implementation

[0032] To clearly illustrate the technical features of this solution, the following detailed description, in conjunction with the accompanying drawings, will be provided.

[0033] This application discloses a hydrotalcite-like adsorbent prepared using blast furnace slag, comprising the following steps:

[0034] S1 crushes blast furnace slag to obtain blast furnace slag particles;

[0035] Generally below 100 mesh, the blast furnace slag comprises the following components:

[0036] SiO2: 30-50wt%; CaO: 25-45wt%; Al2O3: 7-20wt%; MgO: 3-15wt%.

[0037] S2 involves acid dissolution of blast furnace slag particles followed by filtration to obtain filtrate.

[0038] The acid dissolution treatment is carried out in the following manner:

[0039] Blast furnace slag particles are placed in hydrochloric acid and stirred for 2-4 hours at 60-80℃; the concentration of the hydrochloric acid is 4-5 mol / L.

[0040] The mass ratio of the blast furnace slag particles to hydrochloric acid is 1:10-15.

[0041] Mg in the filtrate 2+ The concentration in the filtrate is 0.0020-0.027 mol / L;

[0042] The Ca in the filtrate 2+ The concentration in the filtrate is 0.0018-0.012 mol / L.

[0043] S3 mixes the filtrate with an alkaline source and adjusts the pH to alkaline to obtain a suspension;

[0044] The alkaline source is an aqueous solution of sodium hydroxide, and the concentration of sodium hydroxide is 2-4 mol / L; the pH of the suspension is 8.5-13.5.

[0045] S4 involves a hydrothermal reaction of the suspension, followed by filtration, washing, and drying to obtain the adsorbent.

[0046] The hydrothermal reaction is carried out at a temperature of 60-100℃ for a duration of 12-36 hours.

[0047] The process also includes a pretreatment of the suspension prior to the hydrothermal reaction, wherein the pretreatment involves heating at 40-50°C for 1-3 hours.

[0048] The drying temperature is 60-90℃, and the time is 6-12 hours.

[0049] The pore volume of the adsorbent is 0.1-0.4 cm³. 3 / g, specific surface area of ​​50-200m² 2 / g.

[0050] Adsorbents are applied to CO2 adsorption.

[0051] Based on the above steps, the following embodiments and comparative examples are provided.

[0052] Example 1

[0053] S101 crushes blast furnace slag to obtain blast furnace slag particles;

[0054] The blast furnace slag comprises the following components:

[0055] <![CDATA[SiO2(wt%)]]> <![CDATA[Al2O3(wt%)]]> CaO (wt%) MgO (wt%) <![CDATA[Fe2O3(wt%)]]> <![CDATA[Na2O(wt%)]]> 38.794 8.465 38.538 10.58 0.28 0.443

[0056] S102 involves acid dissolution of blast furnace slag particles followed by filtration to obtain filtrate.

[0057] The acid dissolution treatment is carried out in the following manner:

[0058] Blast furnace slag particles were placed in hydrochloric acid and stirred at 60°C for 2 hours; the concentration of the hydrochloric acid was 4 mol / L.

[0059] The mass ratio of the blast furnace slag particles to hydrochloric acid is 1:10.

[0060] Mg in the filtrate 2+ The concentration in the filtrate was 0.0020 mol / L;

[0061] The Ca in the filtrate 2+ The concentration in the filtrate was 0.0018 mol / L;

[0062] S103 mixes the filtrate with an alkaline source and adjusts the pH to alkaline to obtain a suspension;

[0063] The alkaline source is an aqueous solution of sodium hydroxide, and the concentration of sodium hydroxide is 2 mol / L; the pH of the suspension is 8.5.

[0064] S104 pretreatment of the suspension, hydrothermal reaction, filtration, washing and drying to obtain the adsorbent;

[0065] For the pretreatment of the suspension, the pretreatment is heating at 40°C for 3 hours.

[0066] The hydrothermal reaction was carried out at a temperature of 60°C for 36 hours.

[0067] The drying temperature is 60℃ and the time is 12 hours.

[0068] Its XRD characterization is shown in Figure 1 The curve marked 8.5; SEM plot see Figure 3 .

[0069] Example 2:

[0070] S201 crushes blast furnace slag to obtain blast furnace slag particles;

[0071] The blast furnace slag comprises the following components:

[0072] <![CDATA[SiO2(wt%)]]> <![CDATA[Al2O3(wt%)]]> CaO (wt%) MgO (wt%) <![CDATA[Fe2O3(wt%)]]> <![CDATA[Na2O(wt%) <!-- 3 -->]]> 38.794 8.465 38.538 10.58 0.28 0.443

[0073] S202 involves acid dissolution of blast furnace slag particles followed by filtration to obtain filtrate.

[0074] The acid dissolution treatment is carried out in the following manner:

[0075] Blast furnace slag particles were placed in hydrochloric acid and stirred at 80°C for 4 hours; the concentration of the hydrochloric acid was 5 mol / L.

[0076] The mass ratio of the blast furnace slag particles to hydrochloric acid is 1:15.

[0077] Mg in the filtrate 2+ The concentration in the filtrate was 0.027 mol / L;

[0078] The Ca in the filtrate 2+ The concentration in the filtrate was 0.012 mol / L;

[0079] S203 mixes the filtrate with an alkaline source and adjusts the pH to alkaline to obtain a suspension;

[0080] The alkaline source is an aqueous solution of sodium hydroxide, and the concentration of sodium hydroxide is 4 mol / L; the pH of the suspension is 13.5.

[0081] S204 pretreatment of the suspension, hydrothermal reaction, filtration, washing and drying to obtain the adsorbent;

[0082] For the pretreatment of the suspension, the pretreatment is heating at 50°C for 1 hour.

[0083] The hydrothermal reaction was carried out at a temperature of 100°C for 12 hours.

[0084] The drying temperature is 90℃ and the time is 6 hours.

[0085] XRD characterization is shown in [reference needed]. Figure 1 The curve marked 13.5.

[0086] Example 3:

[0087] S301 crushes blast furnace slag to obtain blast furnace slag particles;

[0088] The blast furnace slag comprises the following components:

[0089] <![CDATA[SiO2(wt%)]]> <![CDATA[Al2O3(wt%)]]> CaO (wt%) MgO (wt%) <![CDATA[Fe2O3(wt%)]]> <![CDATA[Na2O(wt%)]]> 38.794 8.465 38.538 10.58 0.28 0.443

[0090] S302 involves acid dissolution of blast furnace slag particles followed by filtration to obtain filtrate.

[0091] The acid dissolution treatment is carried out in the following manner:

[0092] Blast furnace slag particles were placed in hydrochloric acid and stirred at 60°C for 2 hours; the concentration of the hydrochloric acid was 4 mol / L.

[0093] The mass ratio of the blast furnace slag particles to hydrochloric acid is 1:10.

[0094] Mg in the filtrate 2+ The concentration in the filtrate was 0.0020 mol / L;

[0095] The Ca in the filtrate 2+ The concentration in the filtrate was 0.0018 mol / L;

[0096] S303 mixes the filtrate with an alkaline source and adjusts the pH to alkaline to obtain a suspension;

[0097] The alkaline source is an aqueous solution of sodium hydroxide, and the concentration of sodium hydroxide is 2 mol / L; the pH of the suspension is 8.5.

[0098] S304 pretreatment of the suspension, hydrothermal reaction, filtration, washing and drying to obtain the adsorbent;

[0099] The hydrothermal reaction was carried out at a temperature of 60°C for 36 hours.

[0100] The drying temperature is 60℃ and the time is 12 hours.

[0101] Comparative Example 1:

[0102] Based on Example 1, the raw material blast furnace slag was replaced with coal gangue, while other conditions remained the same.

[0103] XRD characterization is shown in [reference needed]. Figure 2 The curve marked 1.

[0104] Comparative Example 2:

[0105] Based on Example 1, the raw material blast furnace slag was replaced with alumina.

[0106] XRD characterization is shown in [reference needed]. Figure 2 The curve marked 2.

[0107] Comparative Example 3:

[0108] Based on Example 1, the acid dissolution conditions of S101 were changed to 40°C for 2 hours.

[0109] Mg in the filtrate 2+The concentration in the filtrate was 0.0008 mol / L;

[0110] The Ca in the filtrate 2+ The concentration in the filtrate was 0.0010 mol / L.

[0111] XRD characterization is shown in [reference needed]. Figure 2 The curve marked 3.

[0112] The adsorption molecular sieves obtained in the above examples and comparative examples were characterized and their CO2 adsorption capacity at 298 K was measured, as shown in the table below:

[0113]

[0114] It can be seen that heteroatoms can greatly improve the CO2 adsorption capacity of hydrotalcite-like materials prepared from blast furnace slag. The specific reasons are analyzed as follows;

[0115] 1. Layered structure and adjustable interlayer spacing

[0116] Hydrotalcite-like materials possess a layered structure, consisting of alternating layers of positively charged metal hydroxides and negatively charged anions. This structure allows for optimization of CO2 adsorption by modulating the interlayer spacing and interlayer anions.

[0117] 2. Surface alkaline sites

[0118] The surface of hydrotalcite-like materials is rich in basic sites (such as hydroxyl groups and metal oxides), which can chemisorb CO2. CO2 is an acidic gas and readily reacts with these basic sites to form carbonates or bicarbonates. The number and strength of these basic sites can be optimized by adjusting the composition of the hydrotalcite-like material (such as the types and proportions of metal ions).

[0119] 3. High specific surface area and porous structure

[0120] Hydrotalcite-like materials typically possess high specific surface area and porous structures, providing more active sites for the physical adsorption of CO2. Their pore structure and specific surface area can be further controlled through synthesis (e.g., co-precipitation, hydrothermal methods), thereby increasing the CO2 adsorption capacity.

[0121] 5. Thermal stability and regeneration performance

[0122] Hydrotalcite-like materials exhibit good thermal stability, maintaining structural integrity at high temperatures, making them suitable for CO2 adsorption under high-temperature conditions. Hydrotalcite-like materials can be regenerated through simple heat treatment (such as calcination), releasing the adsorbed CO2 and allowing the material to be reused.

[0123] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0124] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A hydrotalcite-like adsorbent prepared using blast furnace slag, characterized in that: Includes the following steps: Blast furnace slag is crushed to obtain blast furnace slag particles; The blast furnace slag particles are acid-dissolved and then filtered to obtain the filtrate. The filtrate is mixed with an alkaline source, and the pH is adjusted to alkaline to obtain a suspension. The suspension was subjected to a hydrothermal reaction, followed by filtration, washing, and drying to obtain the adsorbent. Mg in the filtrate 2+ The total molar percentage of metals in the filtrate was 0.0026-0.027 mol; The Ca in the filtrate 2+ The total metal content in the filtrate is 0.0018-0.012 mol.

2. The hydrotalcite-like adsorbent prepared from blast furnace slag according to claim 1, characterized in that: The blast furnace slag comprises the following components: SiO2: 30-50wt%; CaO: 25-45wt%; Al2O3: 7-20wt%; MgO: 3-15wt%.

3. The hydrotalcite-like adsorbent prepared from blast furnace slag according to claim 1, characterized in that: The alkaline source is an aqueous solution of sodium hydroxide, and the concentration of sodium hydroxide is 2-4 mol / L; the pH of the suspension is 8.5-13.

5.

4. The hydrotalcite-like adsorbent prepared from blast furnace slag according to claim 1, characterized in that: The hydrothermal reaction is carried out at a temperature of 60-100℃ for a duration of 12-36 hours. The process also includes a pretreatment of the suspension prior to the hydrothermal reaction, wherein the pretreatment involves heating at 40-50°C for 1-3 hours.

5. The hydrotalcite-like adsorbent prepared from blast furnace slag according to claim 1, characterized in that: The drying temperature is 60-90℃, and the time is 6-12 hours.

6. The hydrotalcite-like adsorbent prepared from blast furnace slag according to claim 1, characterized in that: The pore volume of the adsorbent is 0.1-0.4 cm³. 3 / g, specific surface area of ​​50-200m² 2 / g.

7. The hydrotalcite-like adsorbent prepared from blast furnace slag according to claim 1, characterized in that: The acid dissolution treatment is carried out in the following manner: Place the blast furnace slag particles in hydrochloric acid and stir for 2-4 hours at 60-80℃.

8. The hydrotalcite-like adsorbent prepared from blast furnace slag according to claim 7, characterized in that: The concentration of the hydrochloric acid is 4-5 mol / L.

9. The hydrotalcite-like adsorbent prepared from blast furnace slag according to claim 7, characterized in that: The mass ratio of the blast furnace slag particles to hydrochloric acid is 1:10-15.

10. The application of the hydrotalcite-like adsorbent according to any one of claims 1-9 in CO2 adsorption.

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