Method for preparing efficient adsorbent from coal gasification slag and obtained efficient adsorbent

Abstract

The invention provides a method for preparing an efficient adsorbent from coal gasification slag and the obtained efficient adsorbent, and relates to the technical field of preparation of desulfurization adsorbents. The method comprises the following steps: sequentially carrying out cleaning, drying, screening, grinding activation and acid leaching pretreatment on a coal gasification slag raw material to obtain pretreated coal gasification slag; the method comprises the following steps: firstly, adding pretreated coal gasification slag into a tetramethylammonium hydroxide aqueous solution, stirring, separating, washing and drying to obtain coal gasification slag without organic toxins; adding the organic poison removed coal gasification slag into an alkali solution, stirring, separating, washing and drying to obtain modified coal gasification slag; and loading an active component on the modified coal gasification slag carrier to obtain the efficient adsorbent. Through TMAH and inorganic strong base modification, the pore structure of the coal gasification slag is optimized, the specific surface area of the coal gasification slag is enlarged, and the adsorbent prepared by loading different active components with the modified product as a carrier shows efficient adsorption performance.

Description

Technical Field

[0001] This invention relates to the fields of solid waste resource utilization technology and high-efficiency adsorbent preparation technology, and particularly to a method for preparing a high-efficiency adsorbent using coal gasification slag and the obtained high-efficiency adsorbent. Background Technology

[0002] my country's natural resources are characterized by "abundant coal, scarce oil and gas." While coal resources are relatively plentiful, proven reserves of oil and natural gas are relatively small, insufficient to meet domestic consumption demand. This necessitates large-scale imports of oil and natural gas, creating a degree of external dependence on these resources. Therefore, ensuring the sustainable utilization of coal resources is of great significance to national energy security.

[0003] Coal gasification is a process that converts coal into clean, combustible gases (mainly hydrogen and carbon monoxide) through high-temperature gasification. During gasification, solid waste, coal gasification slag, is generated. Currently, the primary method for disposing of this slag in China is landfill, which has numerous drawbacks, including high transportation costs, land encroachment, and water and soil pollution. Utilizing coal gasification slag for high-value purposes is of great significance for reducing environmental pollution, conserving land resources, and promoting the sustainable development of coal resources.

[0004] Coal gasification slag has a complex composition, mainly consisting of residual carbon, oxides, sulfides, sulfates, amorphous glassy phases, and crystalline minerals. The mineral phases endow the coal gasification slag with high hardness and particle size, while the porous structure of the residual carbon gives it a large specific surface area and porosity, making it a potential candidate for preparing highly efficient adsorbents.

[0005] Patent CN114405240A discloses a method for preparing denitrification materials using coal gasification slag. This patent utilizes a potassium hydroxide alkaline dissolution method to destroy the aluminosilicate structure on the surface of the coal gasification slag, exposing pores and increasing the specific surface area. However, this method may lead to excessive dissolution of minerals, resulting in severe damage to the mineral phase structure, a reduced micropore ratio, and weakened adsorbent performance. Furthermore, the residual carbon contains polycyclic aromatic hydrocarbons (PAHs, such as benzo[a]pyrene, anthracene, phenanthrene, and naphthalene) and organochlorides (such as chlorobenzene and chlorophenol), which are highly toxic. The potassium hydroxide alkaline dissolution method is insufficient to remove these organic toxins, posing safety hazards to the prepared adsorbent during use. Therefore, there is an urgent need to develop safer and more efficient adsorbent preparation processes to promote the industrial application of coal gasification slag in the adsorbent field. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a method for preparing a high-efficiency adsorbent using coal gasification slag. The prepared adsorbent has the advantages of large specific surface area and pore volume, wide adsorption range of pollutants, and simple and efficient preparation process. Furthermore, the high-value utilization of coal gasification slag solid waste is of great significance for promoting the green development of coal resources.

[0007] One of the objectives of this invention is to provide a method for preparing a high-efficiency adsorbent using coal gasification slag.

[0008] The second objective of this invention is to provide a highly efficient adsorbent prepared by this method.

[0009] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted:

[0010] In a first aspect, the present invention provides a method for preparing a high-efficiency adsorbent using coal gasification slag, comprising the following steps:

[0011] (1) The coal gasification slag raw material is sequentially cleaned, dried, screened, ground, activated and acid leached to obtain pretreated coal gasification slag.

[0012] (2) First, add the pretreated coal gasification slag to a tetramethylammonium hydroxide aqueous solution, stir, separate, wash, and dry to obtain coal gasification slag with organic toxins removed; then add the coal gasification slag with organic toxins removed to an alkaline solution, stir, separate, wash, and dry to obtain modified coal gasification slag.

[0013] (3) The active components are loaded onto the modified coal gasification slag carrier to obtain a high-efficiency adsorbent.

[0014] This invention first pretreats the coal gasification slag, then synergistically modifies it with tetramethylammonium hydroxide (TMAH) and inorganic strong bases (such as sodium hydroxide NaOH and potassium hydroxide KOH) to optimize the pore structure of the coal gasification slag, significantly increase the specific surface area, and improve the proportion of micropores and mesopores. Finally, the modified coal gasification slag is used as a carrier to load the active components, thereby preparing a highly efficient adsorbent.

[0015] Coal gasification slag is a solid waste generated during the coal gasification process. The components of coal gasification slag include residual carbon, oxides, sulfides, sulfates, amorphous glassy phase, and crystalline minerals. Its loss on ignition should not be less than 25%, and the total content of SiO2, Al2O3, Fe2O3, and CaO in the ash should not be less than 85%.

[0016] In some implementations, step (1) specifically includes the following steps:

[0017] First, rinse the gasification slag 2-3 times with deionized water at a mass ratio of 1:3 to 1:5 to remove dust and impurities. Dry it at 100-120℃ until the moisture content on an air-dried basis is less than 5%. Screen and collect the gasification slag with a particle size of 0.15-1.0 mm (this part of the gasification slag contains more residual carbon. Enriching the residual carbon in a porous structure increases the specific surface area and porosity of the gasification slag). Grind the gasification slag into fine particles with a particle size of less than 500 μm. Soak it in 5-10% dilute hydrochloric acid for 24-48 hours to remove ash and metal impurities. Wash it with water until neutral.

[0018] In some embodiments, in step (2), the molar concentration of the tetramethylammonium hydroxide aqueous solution is 0.5-2 mol / L, and the mass ratio of the pretreated coal gasification slag to the tetramethylammonium hydroxide aqueous solution is 1:10-1:20.

[0019] In some embodiments, in step (2), the stirring temperature of the tetramethylammonium hydroxide aqueous solution is 40-60°C and the stirring time is 2-3 hours.

[0020] In some embodiments, the specific steps of preparing the coal gasification slag detoxified with organic toxins in step (2) include: adding fine coal gasification slag particles to a 0.5-2.0M tetramethylammonium hydroxide aqueous solution at a mass ratio of 1:10 to 1:20, stirring magnetically in a constant temperature water bath at 40-60℃ for 2-3 hours, centrifuging, rinsing the coal gasification slag 2-3 times with hot water at 40-60℃ at a mass ratio of 1:3 to 1:5, and drying at 100-120℃ for 4-6 hours to obtain the coal gasification slag detoxified with organic toxins.

[0021] The role of TMAH in coal gasification slag is as follows: First, tetramethylammonium ions (TMA)... + As an organic cation, it can insert into the interlayer of layered organic compounds (such as polycyclic aromatic hydrocarbons (PAHs) and organochlorides), disrupting their layered structure and causing them to dissolve in solution. This significantly reduces the content of PAHs and organochlorides in coal gasification slag, thus reducing toxicity. Secondly, TMA... + Lipophilic, it can insert into the interlayers or pores of minerals, forming a "template effect" to prevent the collapse of mineral structures, maintain mesoporous / microporous structures, and increase specific surface area. Finally, the strong alkalinity of TMAH (pH>12) can catalyze the hydrolysis of organic compounds such as esters, ethers, and amides in coal gasification slag, generating soluble carboxylates, alcohols, or amines, reducing organic residues, while improving surface properties, exposing more oxygen-containing functional groups such as hydroxyl (-OH) and carboxyl (-COOH) groups, and enhancing chemisorption capacity.

[0022] In some embodiments, in step (2), the alkaline solution is a NaOH solution or a KOH solution, the molar concentration of the alkaline solution is 0.5-2 mol / L, and the mass ratio of the coal gasification slag to the alkaline solution after removing organic toxins is 1:5-1:10.

[0023] In some embodiments, in step (2), the stirring temperature of the alkaline solution is 40-60°C and the stirring time is 2-3 hours.

[0024] In some embodiments, step (2), the specific steps for preparing modified coal gasification slag from coal gasification slag after removing organic toxins, include:

[0025] Add the deorganized coal gasification slag to a 0.5-2.0M inorganic strong alkaline solution at a mass ratio of 1:5 to 1:10. Stir magnetically in a constant temperature water bath at 40-60℃ for 2-3 hours, centrifuge, and repeatedly wash the precipitate with deionized water until the pH of the washing solution is 7. Dry at 100-120℃ for 6-8 hours to obtain the modified coal gasification slag carrier.

[0026] Alkaline solutions are used to dissolve minerals (such as silicates) and expand the mesopores.

[0027] The modified coal gasification slag obtained in step (2) has a specific surface area greater than 600 m². 2 / g, pore volume greater than 0.70cm³ 3 / g.

[0028] In some implementations, step (3) includes one of the following methods:

[0029] Method 1: Mix the coal gasification slag carrier with a 1.0-3.0 mol / L active component salt (such as potassium carbonate K2CO3, sodium carbonate Na2CO3) solution at a mass ratio of 1:5 to 1:10, sonicate for 20-30 minutes, stir continuously at room temperature for 10-12 hours, evaporate to a gel state in a water bath at 60-80℃, wash 2-3 times with ethanol or deionized water, vacuum dry at 80-100℃ for 8-12 hours, slowly heat to 200-500℃ under a nitrogen atmosphere, keep at that temperature for 2-3 hours, and cool naturally at room temperature to obtain a high-efficiency CO2 adsorbent.

[0030] The adsorption capacity can reach 80-200 mg / g at a temperature of 15-35℃, a flow rate of 30-70 mL / min, and a CO2 concentration of 10-15%.

[0031] Method 2: Mix the coal gasification slag carrier with a 0.1-1.0 mol / L active component salt (such as manganese nitrate Mn(NO3)2 or zinc nitrate Zn(NO3)2) solution at a mass ratio of 1:5 to 1:10, sonicate for 20-30 minutes, stir continuously at room temperature for 10-12 hours, evaporate to a gel state in a water bath at 60-80℃, wash 2-3 times with ethanol or deionized water, vacuum dry at 80-100℃ for 8-12 hours, slowly heat to 200-500℃ under a nitrogen atmosphere, keep at that temperature for 2-3 hours, and allow to cool naturally at room temperature to obtain a high-efficiency formaldehyde adsorbent.

[0032] At temperatures of 15–35℃, flow rates of 50–150 mL / min, and formaldehyde concentrations of 2 mg / L, the adsorption capacity can reach 80–150 mg / g.

[0033] Method 3: Mix the coal gasification slag carrier with a 0.1-1.0 mol / L solution of active component salt (such as zinc nitrate Zn(NO3)2, manganese nitrate Mn(NO3)2, copper nitrate Cu(NO3)2, ferric nitrate Fe(NO3)3) at a mass ratio of 1:5 to 1:10, sonicate for 20-30 minutes, stir continuously at room temperature for 10-12 hours, evaporate to a gel state in a water bath at 60-80℃, wash 2-3 times with ethanol or deionized water, vacuum dry at 80-100℃ for 8-12 hours, slowly heat to 200-500℃ under a nitrogen atmosphere, keep at that temperature for 2-3 hours, and cool naturally at room temperature to obtain a high-efficiency hydrogen sulfide adsorbent.

[0034] Under conditions of temperature 15–35℃, flow rate 20 mL / min, hydrogen sulfide concentration 1000 ppm, and carrier gas N2, the adsorption capacity can reach 50–80 mg / g.

[0035] Method 4: Mix the coal gasification slag carrier with a 0.1-1.0 mol / L solution of active component salt (such as ferric nitrate Fe(NO3)3 or manganese nitrate Mn(NO3)2) at a mass ratio of 1:5 to 1:10, sonicate for 20-30 minutes, stir continuously at room temperature for 10-12 hours, evaporate to a gel state in a water bath at 60-80℃, wash 2-3 times with ethanol or deionized water, vacuum dry at 80-100℃ for 8-12 hours, slowly heat to 200-500℃ under a nitrogen atmosphere, keep at that temperature for 2-3 hours, and cool naturally at room temperature to obtain a high-efficiency methylene blue (MB) adsorbent.

[0036] The adsorption capacity can reach 50-150 mg / g at a temperature of 15-35℃, pH of 6-7, and MB concentration of 20 mg / L.

[0037] Secondly, the present invention provides a highly efficient adsorbent prepared by the above method.

[0038] Technical effects:

[0039] This invention uses solid waste coal gasification slag generated from coal gasification processes as raw material. By modifying it with tetramethylammonium hydroxide (TMAH) and inorganic strong bases (such as sodium hydroxide NaOH and potassium hydroxide KOH), the pore structure of the coal gasification slag is optimized and the specific surface area of ​​the coal gasification slag is expanded. Using this modified product as a carrier, the adsorbent prepared by loading different active components exhibits high adsorption performance and shows a wide range of adsorption capabilities for various pollutants.

[0040] The present invention has been described in detail above; however, the above embodiments are merely illustrative in nature and are not intended to limit the invention. Furthermore, this document is not limited to the foregoing prior art or the invention itself, or to any theory described in the following embodiments. Detailed Implementation

[0041] The present invention will be further described below with reference to the embodiments. It should be noted that the following embodiments are provided for illustrative purposes only and do not constitute a limitation on the scope of protection of the present invention.

[0042] Unless otherwise specified, the raw materials, reagents, and methods used in the embodiments are all conventional raw materials, reagents, and methods in the art.

[0043] The raw material for coal gasification slag comes from the No. 2 Fertilizer Plant of Qilu Petrochemical Company, with a capacity of 100,000 Nm³. 3 / h Texaco coal-water slurry gasifier, loss on ignition ≥35%, ash content SiO2+Al2O3+Fe2O3+CaO≥90%.

[0044] Example 1

[0045] First, rinse the coal gasification slag twice with deionized water at a mass ratio of 1:3 to remove dust and impurities. Dry it at 120℃ for 6 hours until the air-dried moisture content is less than 5%. Collect the coal gasification slag with a particle size of 0.15-1.0 mm by sieving. Grind it to a particle size of less than 500 μm. Soak it in 10% dilute hydrochloric acid for 24 hours to remove ash and metal impurities. Wash it with water until neutral.

[0046] Then, the fine particles of coal gasification slag were added to a 2.0M TMAH solution at a mass ratio of 1:15. The mixture was then magnetically stirred in a 60℃ constant temperature water bath for 3 hours, centrifuged, and the coal gasification slag was washed three times with 50℃ hot water at a mass ratio of 1:5. Finally, it was dried at 120℃ for 6 hours.

[0047] Then, the fine particles of coal gasification slag were added to a 2.0M NaOH solution at a mass ratio of 1:10. The mixture was then magnetically stirred in a 40℃ water bath for 2 hours, centrifuged, and the precipitate was repeatedly washed with deionized water until the washing solution reached pH 7. The precipitate was then dried at 120℃ for 6 hours to obtain the coal gasification slag carrier with a specific surface area of ​​651 m². 2 / g, pore volume 0.75cm³ 3 / g.

[0048] Then, the coal gasification slag carrier was mixed with 3.0 mol / L potassium nitrate K2CO3 solution at a mass ratio of 1:10, ultrasonically dispersed for 20 minutes, continuously stirred at room temperature for 12 hours, evaporated in a water bath at 60℃ to a gel state, washed three times with ethanol, vacuum dried at 80℃ for 12 hours, heated to 500℃ at 5℃ / min under a nitrogen atmosphere, held at that temperature for 2 hours, and naturally cooled to room temperature to obtain CO2 high-efficiency adsorbent IA.

[0049] Adsorption experiments were conducted in a fixed-bed reactor. A CO2 / N2 mixed gas (CO2:15%, N2:85%) was introduced, the adsorbent dosage was 5.0 g, the flow rate was 50 mL / min, the temperature was 25 °C, and the CO2 adsorption capacity was 154 mg / g.

[0050] Example 2

[0051] First, rinse the coal gasification slag twice with deionized water at a mass ratio of 1:3 to remove dust and impurities. Dry it at 120℃ for 6 hours until the air-dried moisture content is less than 5%. Collect the coal gasification slag with a particle size of 0.15-1.0 mm by sieving. Grind it to a particle size of less than 500 μm. Soak it in 10% dilute hydrochloric acid for 24 hours to remove ash and metal impurities. Wash it with water until neutral.

[0052] Then, the fine particles of coal gasification slag were added to a 1.0M TMAH solution at a mass ratio of 1:20, and the mixture was magnetically stirred in a 60℃ constant temperature water bath for 3 hours. After centrifugation, the coal gasification slag was washed three times with 50℃ hot water at a mass ratio of 1:5 and dried at 120℃ for 6 hours.

[0053] Then, the fine particles of coal gasification slag were added to a 2.0M KOH solution at a mass ratio of 1:8. The mixture was then magnetically stirred in a 40℃ water bath for 2 hours, centrifuged, and the precipitate was repeatedly washed with deionized water until the washing solution reached pH 7. The precipitate was then dried at 120℃ for 6 hours to obtain the coal gasification slag carrier with a specific surface area of ​​658 m². 2 / g, pore volume 0.76cm³ 3 / g.

[0054] Then, the coal gasification slag carrier was mixed with 1.0 mol / L zinc nitrate Zn(NO3)2 at a mass ratio of 1:10, ultrasonically dispersed for 20 minutes, continuously stirred at room temperature for 12 hours, evaporated in a 60℃ water bath until gel-like, washed three times with ethanol, vacuum dried at 80℃ for 12 hours, heated to 500℃ at 5℃ / min under a nitrogen atmosphere, kept at that temperature for 2 hours, and naturally cooled to room temperature to obtain formaldehyde high-efficiency adsorbent IIA.

[0055] Adsorption experiments were conducted in a fixed-bed reactor. Dry nitrogen gas carrying 2 mg / L of formaldehyde gas was introduced. The amount of adsorbent used was 2.0 g, the flow rate was 100 mL / min, the temperature was 35 °C, and the formaldehyde adsorption capacity was 130 mg / g.

[0056] Example 3

[0057] First, rinse the coal gasification slag twice with deionized water at a mass ratio of 1:3 to remove dust and impurities. Dry it at 120℃ for 6 hours until the air-dried moisture content is less than 5%. Collect the coal gasification slag with a particle size of 0.15-1.0 mm by sieving. Grind it to a particle size of less than 500 μm. Soak it in 10% dilute hydrochloric acid for 24 hours to remove ash and metal impurities. Wash it with water until neutral.

[0058] Then, the fine particles of coal gasification slag were added to a 2.0M TMAH solution at a mass ratio of 1:15. The mixture was then magnetically stirred in a 60℃ constant temperature water bath for 3 hours, centrifuged, and the coal gasification slag was washed three times with 50℃ hot water at a mass ratio of 1:5. Finally, it was dried at 120℃ for 6 hours.

[0059] Then, the fine particles of coal gasification slag were added to a 2.0M NaOH solution at a mass ratio of 1:10. The mixture was then magnetically stirred in a 40℃ water bath for 2 hours, centrifuged, and the precipitate was repeatedly washed with deionized water until the washing solution reached pH 7. The precipitate was then dried at 120℃ for 6 hours to obtain the coal gasification slag carrier with a specific surface area of ​​657 m². 2 / g, pore volume 0.75cm³ 3 / g.

[0060] Then, the coal gasification slag carrier was mixed with 1.0 mol / L copper nitrate Cu(NO3)2 solution at a mass ratio of 1:10, ultrasonically dispersed for 20 minutes, continuously stirred at room temperature for 12 hours, evaporated in a water bath at 60℃ to a gel state, washed three times with ethanol, vacuum dried at 80℃ for 12 hours, heated to 300℃ at 5℃ / min under a nitrogen atmosphere, kept at that temperature for 2 hours, and naturally cooled to room temperature to obtain H2S high-efficiency adsorbent IIIA.

[0061] Adsorption experiments were conducted in a fixed-bed reactor, with H2S / N2 mixed gas (H2S concentration 1000ppm, flow rate 20mL / min) introduced, adsorbent dosage 5.0g, temperature 30℃, and H2S saturation adsorption capacity 65mg / g.

[0062] Example 4

[0063] First, rinse the coal gasification slag twice with deionized water at a mass ratio of 1:3 to remove dust and impurities. Dry it at 120℃ for 6 hours until the air-dried moisture content is less than 5%. Collect the coal gasification slag with a particle size of 0.15-1.0 mm by sieving. Grind it to a particle size of less than 500 μm. Soak it in 10% dilute hydrochloric acid for 24 hours to remove ash and metal impurities. Wash it with water until neutral.

[0064] Then, the fine particles of coal gasification slag were added to a 2.0M TMAH solution at a mass ratio of 1:15. The mixture was then magnetically stirred in a 60℃ constant temperature water bath for 3 hours, centrifuged, and the coal gasification slag was washed three times with 50℃ hot water at a mass ratio of 1:5. Finally, it was dried at 120℃ for 6 hours.

[0065] Then, the fine particles of coal gasification slag were added to a 2.0M NaOH solution at a mass ratio of 1:8. The mixture was then magnetically stirred in a 40℃ water bath for 2 hours, centrifuged, and the precipitate was repeatedly washed with deionized water until the washing solution reached pH 7. The precipitate was then dried at 120℃ for 6 hours to obtain the coal gasification slag carrier with a specific surface area of ​​654 m². 2 / g, pore volume 0.76cm³3 / g.

[0066] Then, the coal gasification slag carrier was mixed with 1.0 mol / L manganese nitrate Mn(NO3)2 at a mass ratio of 1:10, ultrasonically dispersed for 20 minutes, continuously stirred at room temperature for 12 hours, evaporated in a water bath at 60℃ to a gel state, washed three times with ethanol, vacuum dried at 80℃ for 12 hours, heated to 500℃ at 5℃ / min under a nitrogen atmosphere, held at that temperature for 2 hours, and naturally cooled to room temperature to obtain methylene blue (MB) high-efficiency adsorbent IVA.

[0067] Weigh 0.1g of adsorbent IVA and add 50mL of MB solution with a concentration of 20mg / L. Adjust the pH of the MB solution to 7 and shake at 150rpm at 25℃ until adsorption equilibrium is reached. The MB adsorption capacity is 121mg / g.

[0068] Comparative Example 1

[0069] First, the coal gasification slag is rinsed twice with deionized water at a mass ratio of 1:3 to remove dust and impurities. It is then dried at 120℃ for 6 hours until the air-dried moisture content is below 5%. The coal gasification slag with a particle size of 0.15–1.0 mm is collected by sieving and ground until the particle size is less than 500 μm to obtain a coal gasification slag carrier with a specific surface area of ​​354 m². 2 / g, pore volume 0.36cm 3 / g.

[0070] Then, the coal gasification slag carrier was mixed with 3.0 mol / L potassium nitrate K2CO3 solution at a mass ratio of 1:10, ultrasonically dispersed for 20 minutes, continuously stirred at room temperature for 12 hours, evaporated in a water bath at 60℃ to a gel state, washed three times with ethanol, vacuum dried at 80℃ for 12 hours, heated to 500℃ at 5℃ / min under a nitrogen atmosphere, held at that temperature for 2 hours, and naturally cooled to room temperature to obtain CO2 adsorbent ⅠB.

[0071] Adsorption experiments were conducted in a fixed-bed reactor. A CO2 / N2 mixed gas (CO2: 15%, N2: 85%) was introduced. The amount of adsorbent used was 5.0 g, the flow rate was 50 mL / min, the temperature was 25 °C, and the CO2 adsorption capacity was 76 mg / g.

[0072] Comparative Example 2

[0073] The CO2 adsorbent was prepared according to the method of Comparative Example 1, except that it was soaked in 10% dilute hydrochloric acid for 24 hours to remove ash and metallic impurities, and then washed with water until neutral to obtain a coal gasification slag carrier with a specific surface area of ​​397 m². 2 / g, pore volume 0.39cm 3 / g.

[0074] Then, the coal gasification slag carrier was mixed with 3.0 mol / L potassium nitrate K2CO3 solution at a mass ratio of 1:10, ultrasonically dispersed for 20 minutes, continuously stirred at room temperature for 12 hours, evaporated in a water bath at 60℃ to a gel state, washed three times with ethanol, vacuum dried at 80℃ for 12 hours, heated to 500℃ at 5℃ / min under a nitrogen atmosphere, held at that temperature for 2 hours, and naturally cooled to room temperature to obtain CO2 adsorbent IIB.

[0075] Adsorption experiments were conducted in a fixed-bed reactor. A CO2 / N2 mixed gas (CO2:15%, N2:85%) was introduced, the adsorbent dosage was 5.0 g, the flow rate was 50 mL / min, the temperature was 25 °C, and the CO2 adsorption capacity was 82 mg / g.

[0076] Comparative Example 3

[0077] The CO2 adsorbent was prepared according to the method of Comparative Example 2, except that fine particles of coal gasification slag were added to a 2.0M NaOH solution at a mass ratio of 1:10. The solution was then magnetically stirred in a 40℃ constant temperature water bath for 2 hours, centrifuged, and the precipitate was repeatedly washed with deionized water until the washing solution pH = 7. The precipitate was then dried at 120℃ for 6 hours to obtain the coal gasification slag carrier with a specific surface area of ​​483 m². 2 / g, pore volume 0.47cm 3 / g.

[0078] Then, the coal gasification slag carrier was mixed with 3.0 mol / L potassium nitrate K2CO3 solution at a mass ratio of 1:10, ultrasonically dispersed for 20 minutes, continuously stirred at room temperature for 12 hours, evaporated in a water bath at 60℃ to a gel state, washed three times with ethanol, vacuum dried at 80℃ for 12 hours, heated to 500℃ at 5℃ / min under a nitrogen atmosphere, held at that temperature for 2 hours, and naturally cooled to room temperature to obtain CO2 adsorbent ⅢB.

[0079] Adsorption experiments were conducted in a fixed-bed reactor. A CO2 / N2 mixed gas (CO2:15%, N2:85%) was introduced, the adsorbent dosage was 5.0 g, the flow rate was 50 mL / min, the temperature was 25 °C, and the CO2 adsorption capacity was 93 mg / g.

[0080] Comparative Example 4

[0081] The CO2 adsorbent was prepared according to the method of Comparative Example 2, except that fine particles of coal gasification slag were added to a 2.0M TMAH solution at a mass ratio of 1:15. The mixture was then magnetically stirred in a 60℃ water bath for 3 hours, centrifuged, and the coal gasification slag was washed three times with 50℃ hot water at a mass ratio of 1:5. Finally, it was dried at 120℃ for 6 hours to obtain a coal gasification slag carrier with a specific surface area of ​​551 m². 2 / g, pore volume 0.65cm 3 / g.

[0082] Then, the coal gasification slag carrier was mixed with 3.0 mol / L potassium nitrate K2CO3 solution at a mass ratio of 1:10, ultrasonically dispersed for 20 minutes, continuously stirred at room temperature for 12 hours, evaporated in a water bath at 60℃ to a gel state, washed three times with ethanol, vacuum dried at 80℃ for 12 hours, heated to 500℃ at 5℃ / min under a nitrogen atmosphere, held at that temperature for 2 hours, and naturally cooled to room temperature to obtain CO2 adsorbent IVB.

[0083] Adsorption experiments were conducted in a fixed-bed reactor. A CO2 / N2 mixed gas (CO2:15%, N2:85%) was introduced, the adsorbent dosage was 5.0 g, the flow rate was 50 mL / min, the temperature was 25 °C, and the CO2 adsorption capacity was 128 mg / g.

[0084] Comparative Example 5

[0085] The CO2 adsorbent was prepared according to the method in Example 1, except that the modification order of TMAH and NaOH solutions was changed. Specifically, the fine particles of coal gasification slag were first added to a 2.0M NaOH solution, followed by the addition of the fine particles to a 2.0M TMAH solution, resulting in CO2 high-efficiency adsorbent VB with a specific surface area of ​​571 m². 2 / g, pore volume 0.67cm 3 / g. Adsorption experiments were conducted in a fixed-bed reactor with a CO2 / N2 mixed gas (CO2:15%, N2:85%), an adsorbent dosage of 5.0 g, a flow rate of 50 mL / min, and a temperature of 25 °C. The CO2 adsorption capacity was 131 mg / g.

[0086] Comparative Example 6

[0087] Patent CN 115090264 B describes a superhydrophobic / superoleophilic adsorbent prepared from coal gasification slag and its preparation method. The adsorbent prepared by the method described in the patent was subjected to adsorption experiments in a fixed-bed reactor. A CO2 / N2 mixed gas (CO2: 15%, N2: 85%) was introduced, the amount of adsorbent was 5.0 g, the flow rate was 50 mL / min, the temperature was 25 °C, and the CO2 adsorption capacity was 73 mg / g.

[0088] This invention provides a method for preparing a high-efficiency adsorbent using coal gasification slag as raw material. First, the "template effect" of TMAH (tumor oxidizing alcohol) is utilized to optimize the pore structure of the coal gasification slag. Then, an inorganic strong alkali is used to disrupt the aluminosilicate structure on the surface of the coal gasification slag, exposing pores and increasing the specific surface area. The adsorbent prepared by the specific method described in this invention has a large specific surface area and a large pore volume, exhibiting good adsorption performance for various gaseous or liquid pollutants.

[0089] The above embodiments are merely illustrative of the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein, without departing from the spirit and substance defined by the claims of the present invention; and such modifications or substitutions are still within the scope defined by the claims of the present invention.

Claims

1. A method for preparing a high-efficiency adsorbent using coal gasification slag, characterized in that, Includes the following steps: (1) The coal gasification slag raw material is sequentially cleaned, dried, screened, ground, activated and acid leached to obtain pretreated coal gasification slag. (2) First, add the pretreated coal gasification slag to a tetramethylammonium hydroxide aqueous solution, stir, separate, wash, and dry to obtain coal gasification slag with organic toxins removed; then add the coal gasification slag with organic toxins removed to an alkaline solution, stir, separate, wash, and dry to obtain modified coal gasification slag. (3) The active components are loaded onto the modified coal gasification slag carrier to obtain a high-efficiency adsorbent.

2. The method according to claim 1, characterized in that, In step (1), the slag burn-off rate of coal gasification is not less than 25%, and the total content of SiO2, Al2O3, Fe2O3 and CaO in the ash is not less than 85%.

3. The method according to claim 1, characterized in that, Step (1) specifically includes the following steps: First, rinse the gasification slag with deionized water 2-3 times at a mass ratio of 1:3 to 1:5 to remove dust and impurities. Dry it at 100-120℃ until the moisture content on an air-dried basis is less than 5%. Collect the gasification slag with a particle size of 0.15-1.0 mm by sieving. Grind the gasification slag into fine particles with a particle size of less than 500 μm. Soak it in 5-10% dilute hydrochloric acid for 24-48 hours to remove ash and metal impurities. Wash it with water until neutral.

4. The method according to claim 1, characterized in that, In step (2), the molar concentration of the tetramethylammonium hydroxide aqueous solution is 0.5-2 mol / L, and the mass ratio of the pretreated coal gasification slag to the tetramethylammonium hydroxide aqueous solution is 1:10-1:

20. In step (2), the stirring temperature of the tetramethylammonium hydroxide aqueous solution is 40-60℃, and the stirring time is 2-3h.

5. The method according to claim 1, characterized in that, In step (2), the alkaline solution is NaOH solution or KOH solution, the molar concentration of the alkaline solution is 0.5-2 mol / L, and the mass ratio of coal gasification slag to alkaline solution after removing organic toxins is 1:5-1:10; In step (2), the stirring temperature of the alkaline solution is 40-60℃ and the stirring time is 2-3h.

6. The method according to claim 1, characterized in that, Step (3) includes the following steps: the coal gasification slag carrier is mixed with a 1.0-3.0 mol / L active component salt solution at a mass ratio of 1:5 to 1:10, ultrasonicated for 20-30 minutes, continuously stirred at room temperature for 10-12 hours, evaporated in a water bath at 60-80℃ until gel-like, washed 2-3 times with ethanol or deionized water, vacuum dried at 80-100℃ for 8-12 hours, slowly heated to 200-500℃ under a nitrogen atmosphere, kept at that temperature for 2-3 hours, and naturally cooled to room temperature to obtain a high-efficiency CO2 adsorbent, wherein the active component salt solution is one or more of potassium carbonate and sodium carbonate.

7. The method according to claim 1, characterized in that, Step (3) includes the following steps: mixing the coal gasification slag carrier with a 0.1-1.0 mol / L active component salt solution at a mass ratio of 1:5 to 1:10, sonicating for 20-30 minutes, continuously stirring at room temperature for 10-12 hours, evaporating in a water bath at 60-80℃ until gel-like, washing with ethanol or deionized water 2-3 times, vacuum drying at 80-100℃ for 8-12 hours, slowly heating to 200-500℃ under a nitrogen atmosphere, holding at that temperature for 2-3 hours, and naturally cooling to room temperature to obtain a formaldehyde high-efficiency adsorbent, wherein the active component salt solution is one or more of manganese nitrate and zinc nitrate.

8. The method according to claim 1, characterized in that, Step (3) includes the following steps: mixing the coal gasification slag carrier with a 0.1-1.0 mol / L active component salt solution at a mass ratio of 1:5 to 1:10, sonicating for 20-30 minutes, continuously stirring at room temperature for 10-12 hours, evaporating in a water bath at 60-80℃ until gel-like, washing with ethanol or deionized water 2-3 times, vacuum drying at 80-100℃ for 8-12 hours, slowly heating to 200-500℃ under a nitrogen atmosphere, holding at that temperature for 2-3 hours, and naturally cooling to room temperature to obtain a high-efficiency hydrogen sulfide adsorbent, wherein the active component salt solution is one or more of zinc nitrate, manganese nitrate, copper nitrate, and ferric nitrate.

9. The method according to claim 1, characterized in that, Step (3) includes the following steps: the coal gasification slag carrier is mixed with a 0.1-1.0 mol / L active component salt solution at a mass ratio of 1:5 to 1:10, ultrasonicated for 20-30 minutes, continuously stirred at room temperature for 10-12 hours, evaporated in a water bath at 60-80℃ until gel-like, washed 2-3 times with ethanol or deionized water, vacuum dried at 80-100℃ for 8-12 hours, slowly heated to 200-500℃ under a nitrogen atmosphere, kept at that temperature for 2-3 hours, and naturally cooled to room temperature to obtain a high-efficiency methylene blue adsorbent, wherein the active component salt solution is one or more of ferric nitrate and manganese nitrate.

10. A highly efficient adsorbent, characterized in that, Prepared by the method described in any one of claims 1-9.