Modified activated carbon with efficient adsorption performance and preparation method thereof

Abstract

The invention provides modified activated carbon with efficient adsorption performance and a preparation method thereof, and relates to the technical field of activated carbon modification. The preparation method of the modified activated carbon with the efficient adsorption performance comprises the following steps: drying activated carbon; mixing the dried activated carbon with a modifier, wherein the modifier comprises but is not limited to two or more of quaternary ammonium salt, pyridine compounds, a cerous nitrate solution, a copper nitrate solution, an amino silane coupling agent, carboxylated carbon nanotubes and chitosan; carrying out heat treatment on the mixed activated carbon, and controlling the temperature to be 300-800 DEG C and the time to be 1-5 hours; and cooling the activated carbon subjected to heat treatment to obtain the modified activated carbon. Through a specific modifier formula and a multi-step modification process, the adsorption capacity of the prepared modified activated carbon to specific pollutants is improved by 30%-50% compared with that of traditional activated carbon, and the adsorption rate is improved by 2-3 times.

Description

Technical Field

[0001] The present invention relates to the technical field of activated carbon modification, and specifically to a modified activated carbon with high adsorption performance and its preparation method. Background Art

[0002] As a carbon material with a highly developed pore structure, activated carbon has been widely used in many fields such as gas adsorption, water treatment, and catalyst carriers. However, traditional activated carbon has problems such as limited adsorption capacity and slow adsorption rate when facing certain specific pollutants. For example, when treating air containing harmful gases such as formaldehyde and benzene, the adsorption efficiency of traditional activated carbon is difficult to meet the demand for rapid air purification; when treating complex organic pollutants in industrial wastewater, its limited adsorption capacity leads to poor treatment effects and the wastewater cannot meet more stringent discharge standards. To overcome these problems and improve the adsorption performance of activated carbon, its modification treatment has become a hot research direction. Summary of the Invention

[0003] Aiming at the deficiencies of the prior art, the present invention provides a modified activated carbon with high adsorption performance and its preparation method, which solves the problems that the adsorption efficiency of traditional activated carbon is difficult to meet the demand for rapid air purification; when treating complex organic pollutants in industrial wastewater, its limited adsorption capacity leads to poor treatment effects and the wastewater cannot meet more stringent discharge standards.

[0004] To achieve the above objectives, the present invention is realized through the following technical solutions: A preparation method of a modified activated carbon with high adsorption performance, comprising the following steps:

[0005] Dry the activated carbon.

[0006] Mix the dried activated carbon with a modifier, and the modifier includes but is not limited to two or more of quaternary ammonium salts, pyridine compounds, cerium nitrate solution, copper nitrate solution, amino silane coupling agent, carboxylated carbon nanotubes, and chitosan;

[0007] Perform heat treatment on the mixed activated carbon, control the temperature at 300°C - 800°C, and the time is 1 - 5 hours;

[0008] Cool the heat-treated activated carbon to obtain the modified activated carbon.

[0009] Preferably, when the modifier contains amino silane coupling agent, carboxylated carbon nanotubes and chitosan, their mass ratio is (2 - 4):(1 - 3):(1 - 2);

[0010] The temperature of the heat treatment is 500°C - 600°C, and the time is 2 - 3 hours.

[0011] Preferably, a method for preparing a modified activated carbon with high adsorption performance further comprises the following steps:

[0012] Activated carbon pretreatment: Crush the activated carbon to 20 - 100 mesh, then soak it in a hydrochloric acid solution with a mass fraction of 5% - 15% for 2 - 4 h. During soaking, the liquid - solid ratio is (5 - 10):1 (mL / g). Filter, wash it with deionized water until neutral, and dry it at 100 - 120 °C for 3 - 5 h for standby;

[0013] Modifier preparation: Mix the selected modifier raw materials in proportion, and react at 30 - 50 °C with a stirring speed of 200 - 500 r / min for 1 - 3 h to obtain a modifier solution;

[0014] Mixing and dispersion: Add the pretreated activated carbon into an aqueous solution of a dispersant with a mass fraction of 1% - 3%, and ultrasonically disperse it for 15 - 30 min to uniformly disperse the activated carbon. Then add the modifier solution and continue to stir and react for 2 - 4 h. The dispersant is one of polyvinylpyrrolidone, sodium dodecylbenzenesulfonate, and polyethylene glycol;

[0015] Cross - linking reaction: Add a cross - linking agent to the above reaction system, and react at 40 - 60 °C for 3 - 6 h to cross - link the modifier with the activated carbon. The cross - linking agent is one of glutaraldehyde, epichlorohydrin, and ethylenediamine;

[0016] Activation treatment: Add an activation assistant to the cross - linked product. The mass ratio of the activation assistant to the cross - linked product is (1 - 3):10, and activate it in a muffle furnace at 500 - 800 °C for 1 - 3 h. The activation assistant is one of potassium carbonate, phosphoric acid, and zinc chloride;

[0017] Post - treatment: Cool the activated product to room temperature, wash it with deionized water until neutral, and dry it to obtain a modified activated carbon with high adsorption performance.

[0018] Preferably, a modified activated carbon with high adsorption performance is prepared by the above - mentioned preparation method.

[0019] Preferably, a modified activated carbon with high adsorption performance, by weight, comprises the following raw materials: 50 - 70 parts of activated carbon, 10 - 20 parts of modifier, 5 - 10 parts of dispersant, 3 - 8 parts of cross - linking agent, and 2 - 6 parts of activation assistant; The activated carbon is one or more of coconut shell activated carbon, coal - based activated carbon, and wood - based activated carbon.

[0020] The present invention provides a modified activated carbon with high adsorption performance and a preparation method thereof. It has the following

[0021] Beneficial effects:

[0022] 1. Through a specific modifier formula and multi-step modification process, the modified activated carbon prepared by the present invention has an adsorption capacity for specific pollutants 30%-50% higher than that of traditional activated carbon, and the adsorption rate is increased by 2-3 times. When treating formaldehyde-containing air, it can reduce the formaldehyde concentration to a safe level in a shorter time; when treating industrial wastewater, the removal effect of organic pollutants is significantly better than that of traditional activated carbon.

[0023] 2. The structure of the modified activated carbon of the present invention is stable. After multiple adsorption-desorption cycles, it can still maintain high adsorption performance and can be reused multiple times, greatly reducing the use cost. For example, in industrial waste gas purification equipment, using the modified activated carbon of the present invention can significantly extend the replacement cycle and reduce the equipment operation cost.

[0024] 3. The preparation method of the present invention has a relatively simple operation process. The equipment and raw materials used are all common industrial materials and equipment, and the reaction conditions are easy to control, suitable for large-scale industrial production, and can meet the large market demand for high-efficiency adsorption materials. Specific Embodiments

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0026] Example 1:

[0027] The embodiment of the present invention provides a modified activated carbon with high adsorption performance and its preparation method, including the following steps:

[0028] Preliminary treatment: First, the activated carbon is dried to remove surface moisture. This step provides a good foundation for subsequent modification operations to ensure that the modifier can better contact and react with the activated carbon.

[0029] Mixing the modifier: The dried activated carbon is mixed with the modifier. The sources of the modifier are extensive, including but not limited to two or more of quaternary ammonium salts, pyridine compounds, cerium nitrate solution, copper nitrate solution, amino silane coupling agent, carboxylated carbon nanotubes, and chitosan. The synergistic effect of multiple modifiers can improve the adsorption performance of activated carbon from different aspects. For example, the amino silane coupling agent can improve the chemical properties of the activated carbon surface and enhance its affinity with certain pollutants; the carboxylated carbon nanotubes, with their unique nano-structure, increase the specific surface area and adsorption sites of the activated carbon; chitosan can improve the hydrophilicity of the activated carbon, making it perform better when treating pollutants in aqueous systems.

[0030] Heat treatment: The mixed activated carbon is heat-treated, with the temperature strictly controlled at 300 °C and the time being 1 hour. The heat treatment process can promote the chemical reaction between the modifier and the activated carbon, further optimize the pore structure and surface properties of the activated carbon, and enhance its adsorption performance. When the modifier includes an amino silane coupling agent, carboxylated carbon nanotubes, and chitosan, their mass ratio is 2:1:1, and the heat treatment temperature is preferably 500 °C and the time is 2 hours. Under these conditions, the synergistic effect of the modifier can be maximally exerted, and the best adsorption performance improvement effect can be obtained.

[0031] Cooling to obtain modified activated carbon: The heat-treated activated carbon is cooled to obtain preliminary modified activated carbon.

[0032] Further treatment, which includes the following steps:

[0033] Activated carbon pretreatment: The activated carbon is crushed to 20 mesh to increase its specific surface area and make its contact with subsequent treatment reagents more sufficient. Then it is immersed in a 5% hydrochloric acid solution for 2 h, and the liquid-solid ratio during immersion is 5:1 (mL / g). The hydrochloric acid immersion can remove impurities on the surface of the activated carbon and activate its surface to a certain extent. After filtration, it is washed with deionized water until neutral and dried at 100 °C for 3 h for standby.

[0034] Modifier preparation: The selected modifier raw materials are mixed in proportion and reacted for 1 h at 30 °C with a stirring speed of 200 r / min. Through this step, the modifier raw materials react fully to form a uniform and stable modifier solution, ensuring that it can be evenly dispersed when mixed with the activated carbon subsequently.

[0035] Mixing and dispersion: The pretreated activated carbon is added to an aqueous solution of a dispersant with a mass fraction of 1%, and ultrasonically dispersed for 15 min. The dispersant can be one of polyvinylpyrrolidone, sodium dodecylbenzenesulfonate, and polyethylene glycol. Ultrasonic dispersion can make the activated carbon evenly dispersed in the solution and avoid agglomeration. Then the modifier solution is added, and stirring and reaction continue for 2 h to make the modifier and the activated carbon contact and combine preliminarily.

[0036] Crosslinking reaction: A crosslinking agent is added to the above reaction system. The crosslinking agent is one of glutaraldehyde, epichlorohydrin, and ethylenediamine, and the reaction is carried out at 40 °C for 3 h. Through the crosslinking reaction, a more stable chemical bond connection is formed between the modifier and the activated carbon, enhancing the structural stability and adsorption performance of the modified activated carbon.

[0037] Activation treatment: An activation aid is added to the crosslinked product. The mass ratio of the activation aid to the crosslinked product is 1:10. The activation aid is one of potassium carbonate, phosphoric acid, and zinc chloride. It is activated in a muffle furnace at 500 °C for 1 h. The activation treatment can further optimize the pore structure of the activated carbon, increase its adsorption active sites, and significantly improve the adsorption performance.

[0038] Post-treatment: The activated product is cooled to room temperature, washed with deionized water until neutral, and dried to obtain modified activated carbon with high adsorption performance. This step removes the impurities remaining in the reaction process and ensures the purity and stability of the modified activated carbon.

[0039] Composition of the modified activated carbon: By weight, the modified activated carbon of the present invention comprises the following raw materials: 50 parts of activated carbon, 10 parts of modifier, 5 parts of dispersant, 3 parts of crosslinking agent, and 2 parts of activation aid. Among them, the activated carbon can be one or more of coconut shell activated carbon, coal-based activated carbon, or wood-based activated carbon. Activated carbons from different sources have different characteristics. By selecting the appropriate activated carbon raw material, the requirements of different application scenarios can be met.

[0040] Example 2:

[0041] The present invention provides a modified activated carbon with high adsorption performance and its preparation method, comprising the following steps:

[0042] Preliminary treatment: First, the activated carbon is dried to remove surface moisture. This step provides a good foundation for subsequent modification operations and ensures that the modifier can better contact and react with the activated carbon.

[0043] Mixing the modifier: The dried activated carbon is mixed with the modifier. The modifier has a wide range of sources, including but not limited to two or more of quaternary ammonium salts, pyridine compounds, cerium nitrate solution, copper nitrate solution, amino silane coupling agent, carboxylated carbon nanotubes, and chitosan. The synergistic effect of multiple modifiers can improve the adsorption performance of the activated carbon from different aspects. For example, the amino silane coupling agent can improve the chemical properties of the activated carbon surface and enhance its affinity with certain pollutants; the carboxylated carbon nanotubes, with their unique nanostructure, increase the specific surface area and adsorption sites of the activated carbon; chitosan can improve the hydrophilicity of the activated carbon, making it perform better when treating pollutants in aqueous systems.

[0044] Heat treatment: The mixed activated carbon is heat-treated at a strictly controlled temperature of 800 °C for 5 hours. The heat treatment process can promote the chemical reaction between the modifier and the activated carbon, further optimize the pore structure and surface properties of the activated carbon, and enhance its adsorption performance. When the modifier contains an amino silane coupling agent, carboxylated carbon nanotubes, and chitosan, their mass ratio is 4:3:2, and the heat treatment temperature is preferably 600 °C for 3 hours. Under these conditions, the synergistic effect of the modifier can be maximally exerted, and the best adsorption performance improvement effect can be obtained.

[0045] Cooling to obtain modified activated carbon: The heat-treated activated carbon is cooled to obtain preliminary modified activated carbon.

[0046] Further treatment, which includes the following steps:

[0047] Pretreatment of activated carbon: The activated carbon is crushed to 100 mesh to increase its specific surface area and make its contact with subsequent treatment reagents more sufficient. Then it is soaked in a hydrochloric acid solution with a mass fraction of 15% for 4 h, and the liquid-solid ratio during soaking is 10:1 (mL / g). The hydrochloric acid soaking can remove the impurities on the surface of the activated carbon and activate its surface to a certain extent. After filtration, it is washed with deionized water until neutral and dried at 120 °C for 5 h for standby.

[0048] Preparation of modifier: The selected modifier raw materials are mixed in proportion and reacted at 50 °C with a stirring speed of 500 r / min for 3 h. Through this step, the modifier raw materials react fully to form a uniform and stable modifier solution, ensuring that it can be evenly dispersed when mixed with the activated carbon subsequently.

[0049] Mixing and dispersion: The pretreated activated carbon is added to an aqueous solution of a dispersant with a mass fraction of 1% - 3%, and ultrasonically dispersed for 30 min. The dispersant can be one of polyvinylpyrrolidone, sodium dodecylbenzenesulfonate, and polyethylene glycol. Ultrasonic dispersion can make the activated carbon evenly dispersed in the solution and avoid agglomeration. Then the modifier solution is added, and the stirring reaction is continued for 4 h to make the modifier fully contact and initially combine with the activated carbon.

[0050] Crosslinking reaction: A crosslinking agent is added to the above reaction system. The crosslinking agent is one of glutaraldehyde, epichlorohydrin, and ethylenediamine, and the reaction is carried out at 60 °C for 6 h. Through the crosslinking reaction, a more stable chemical bond connection is formed between the modifier and the activated carbon, enhancing the structural stability and adsorption performance of the modified activated carbon.

[0051] Activation treatment: An activation aid is added to the cross-linked product. The mass ratio of the activation aid to the cross-linked product is 3:10. The activation aid is one of potassium carbonate, phosphoric acid, and zinc chloride, and it is activated in a muffle furnace at 800 °C for 3 h. The activation treatment can further optimize the pore structure of the activated carbon, increase its adsorption active sites, and significantly improve the adsorption performance.

[0052] Post-treatment: The activated product is cooled to room temperature, washed with deionized water until neutral, and dried to obtain modified activated carbon with high adsorption performance. This step removes the impurities remaining in the reaction process and ensures the purity and stability of the modified activated carbon.

[0053] Composition of the modified activated carbon: By weight, the modified activated carbon of the present invention comprises the following raw materials: 70 parts of activated carbon, 20 parts of modifier, 10 parts of dispersant, 8 parts of cross-linking agent, and 6 parts of activation aid. Among them, the activated carbon can be one or more of coconut shell activated carbon, coal-based activated carbon, or wood-based activated carbon. Activated carbons from different sources have different characteristics, and by selecting the appropriate activated carbon raw material, the requirements of different application scenarios can be met.

[0054] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A preparation method of modified activated carbon with high adsorption performance, characterized in that: It includes the following steps: Dry the activated carbon. Mix the dried activated carbon with a modifier, where the modifier includes but is not limited to two or more of quaternary ammonium salts, pyridine compounds, cerium nitrate solution, copper nitrate solution, amino silane coupling agent, carboxylated carbon nanotubes, and chitosan. Perform heat treatment on the mixed activated carbon, with the temperature controlled at 300°C - 800°C and the time being 1 - 5 hours. Cool the heat-treated activated carbon to obtain modified activated carbon.

2. The preparation method of a modified activated carbon with high adsorption performance according to claim 1, characterized in that: When the modifier contains an amino silane coupling agent, carboxylated carbon nanotubes, and chitosan, their mass ratio is (2 - 4):(1 - 3):(1 - 2). The temperature of the heat treatment is 500°C - 600°C and the time is 2 - 3 hours.

3. The preparation method of a modified activated carbon with high adsorption performance according to claim 1, characterized in that: It also includes the following steps: Activated carbon pretreatment: Crush the activated carbon to 20 - 100 mesh, then soak it in a hydrochloric acid solution with a mass fraction of 5% - 15% for 2 - 4 h. The liquid-solid ratio during soaking is (5 - 10):1 (mL / g). Filter, wash with deionized water until neutral, and dry at 100 - 120°C for 3 - 5 h for standby. Modifier preparation: Mix the selected modifier raw materials in proportion and react at 30 - 50°C with a stirring speed of 200 - 500 r / min for 1 - 3 h to obtain a modifier solution. Mixing and dispersion: Add the pretreated activated carbon to an aqueous solution of a dispersant with a mass fraction of 1% - 3%, and perform ultrasonic dispersion for 15 - 30 min to uniformly disperse the activated carbon. Then add the modifier solution and continue stirring and reacting for 2 - 4 h. The dispersant is one of polyvinylpyrrolidone, sodium dodecylbenzenesulfonate, and polyethylene glycol. Crosslinking reaction: Add a crosslinking agent to the above reaction system and react at 40 - 60°C for 3 - 6 h to crosslink the modifier with the activated carbon. The crosslinking agent is one of glutaraldehyde, epichlorohydrin, and ethylenediamine. Activation treatment: Add an activation aid to the crosslinked product. The mass ratio of the activation aid to the crosslinked product is (1 - 3):10, and activate it in a muffle furnace at 500 - 800°C for 1 - 3 h. The activation aid is one of potassium carbonate, phosphoric acid, and zinc chloride. Post-treatment: Cool the activated product to room temperature, wash it with deionized water until neutral, and dry to obtain modified activated carbon with high adsorption performance.

4. A modified activated carbon with high adsorption performance, characterized in that: Prepared by the preparation method according to any one of claims 1 - 3.

5. The modified activated carbon with high adsorption performance according to claim 4, wherein: By weight, it includes the following raw materials: 50 - 70 parts of activated carbon, 10 - 20 parts of modifier, 5 - 10 parts of dispersant, 3 - 8 parts of crosslinking agent, and 2 - 6 parts of activation aid; the activated carbon is one or more of coconut shell activated carbon, coal-based activated carbon, and wood-based activated carbon.