A rod-shaped activated carbon material and its production process

Abstract

The present invention relates to the technical field of activated carbon, and discloses a rod-shaped activated carbon material and a production process thereof. The rod-shaped activated carbon material comprises the following raw materials in parts by weight: 60-80 parts of functionalized activated carbon particles, 5-15 parts of carboxymethyl cellulose, and 1-5 parts of diatomaceous earth. Functional groups with adsorption activity are bonded to the surface of the activated carbon material to promote multiple effects such as chelation and coordination between the activated carbon material and heavy metal ions in wastewater. Combined with the physical adsorption effect of the activated carbon material itself, the prepared rod-shaped activated carbon material has excellent heavy metal ion adsorption performance and exhibits a higher heavy metal ion adsorption capacity.

Description

Technical Field

[0001] The present invention relates to the technical field of activated carbon, in particular to a rod-shaped activated carbon material and a production process thereof. Background Art

[0002] As we all know, water is a necessity for human survival, and the protection of water resources should be given high attention. However, in recent years, water pollution problems have been exposed continuously. Various persistent, highly toxic and difficult to degrade heavy metal pollutants are discharged in large quantities, resulting in serious water pollution, especially Pb 2+ 、Cu 2+ 、Ni 2+ etc., which can be enriched in organisms such as microorganisms, aquatic plants or animals, and then enter the human body through the food chain, or directly enter the human body through drinking water, seriously endangering human health. Therefore, heavy metal pollution has become one of the important problems in the water environment. In recent years, people have paid more and more attention to their own health problems. Therefore, efficient removal of heavy metal ions in water resources and improving drinking water safety have become research hotspots.

[0003] At present, the most common method for removing heavy metal ions is still to use adsorption technology. Since activated carbon has a large specific surface area and a large number of microporous structures, it can be used as an adsorption material and is widely used in adsorption technology. However, activated carbon can only adsorb heavy metals through physical action. Not only is the adsorption capacity low, but the adsorbed heavy metal ions are not removed in time, which can easily cause secondary pollution. Therefore, in practical applications, it is often necessary to improve the activated carbon material. The Chinese patent application with application number CN201911294431.2 discloses an activated carbon-Ag2O-CuO-Bi2O3 adsorption material and its preparation method and application. Activated carbon-Ag2O-CuO-Bi2O3 adsorption material was prepared by ultrasonic stirring combination method, and the uniform synthesis of activated carbon-Ag2O-CuO-Bi2O3 adsorption material was achieved. By selecting the activated carbon content and the molar ratio of Ag2O, CuO, and Bi2O3, the material has a mixed structure with different shapes, which has a strong adsorption and removal effect on mercury ions, cadmium ions, etc. in wastewater. However, improving the activated carbon material only by changing the shape still cannot change the nature of activated carbon that can only adsorb heavy metal ions by physical action, and it is difficult to effectively improve the heavy metal ion adsorption capacity of the activated carbon material. Summary of the Invention

[0004] The purpose of the present invention is to provide a rod-shaped activated carbon material and a production process thereof, which solves the problem that the activated carbon material can only adsorb heavy metal ions in sewage through physical action, resulting in a low adsorption capacity.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A rod-shaped activated carbon material comprises the following raw materials in parts by weight: 60-80 parts of functionalized activated carbon particles, 5-15 parts of carboxymethyl cellulose, and 1-5 parts of diatomaceous earth;

[0007] The functionalized activated carbon particles are prepared by oxidizing the surface of the activated carbon, then introducing epoxy groups, and then grafting thiosemicarbazide groups.

[0008] Furthermore, the production process of the functionalized activated carbon particles includes:

[0009] ① Place the activated carbon in concentrated nitric acid and reflux at 90-100°C for 1-3 hours. Use deionized water to wash the reaction product until it is neutral and then dry it. Place the product after the post-treatment process in thionyl chloride, stir it evenly, add N,N-dimethylformamide dropwise, and react at 70-80°C for 24-48 hours to obtain acyl chloride-modified activated carbon;

[0010] ②Ultrasonic dispersion of the acyl chloride modified activated carbon material in an organic solvent, adding 1,3-diepoxyglycerol ether glycerol, stirring evenly, placing the reaction system at a temperature of 60-80°C, reacting for 6-18 hours, filtering and separating the solid sample after the reaction, washing the product with deionized water, and vacuum drying to obtain epoxy modified activated carbon;

[0011] ③ Add epoxy-modified activated carbon to N,N-dimethylformamide, ultrasonically disperse, add 1,3-diaminothiourea and sodium hydroxide solution, stir evenly, place the system at 70-90°C, stir and react for 12-24 hours, filter and collect the filter cake after the reaction is completed, wash the filter cake, vacuum dry, and grind to obtain functionalized activated carbon particles.

[0012] Furthermore, in step ②, the organic solvent is any one of tetrahydrofuran, 1,4-dioxane or chloroform.

[0013] Furthermore, in step ②, the mass ratio of the acyl chloride modified activated carbon material to 1,3-diepoxyglyceryl ether glycerol is 1:0.2-0.6.

[0014] Furthermore, in step ③, the ultrasonic power during the ultrasonic dispersion is 200-400 W, and the ultrasonic time is 20-40 min.

[0015] Furthermore, in step ③, the concentration of the sodium hydroxide solution is 0.5-1.5 mol / L.

[0016] Furthermore, in step ③, during the washing, the filter cake is washed with deionized water until the pH value is 6-7.

[0017] Through the above technical solution, after the activated carbon is oxidized by nitric acid, the surface will contain oxygen-containing groups such as carboxyl groups. Using N,N-dimethylformamide as a catalyst and thionyl chloride as an acyl chloride reagent, it is subjected to acyl chloride modification to obtain acyl chloride-modified activated carbon. Due to the high reactivity of the acyl chloride group, it can undergo an esterification reaction with the hydroxyl group in the glycerol structure of 1,3-diepoxyglyceryl ether to generate epoxy-modified activated carbon. In the alkaline environment provided by sodium hydroxide solution, the epoxy-modified activated carbon can further undergo a ring-opening addition reaction with the amino group in the 1,3-diaminothiourea structure to obtain functionalized activated carbon particles.

[0018] A production process for rod-shaped activated carbon material comprises the following steps:

[0019] S1: Pour the functionalized activated carbon particles, carboxymethyl cellulose and diatomaceous earth into a mixer and dry-mix them at a speed of 60-100 rpm to obtain a dry mix;

[0020] S2: adding water to the dry mix prepared in step S1, and wet mixing at a rotation speed of 20-40 rpm to obtain a wet mix;

[0021] S3: Compressing and compacting the wet mixture prepared in step S2 to remove moisture, drying it at 20-35°C for 24-36 hours, and kneading it into cylindrical activated carbon rods using a kneader;

[0022] S4: The cylindrical activated carbon rod prepared in S3 is placed in a vacuum drying oven at 40-50°C and dried for 6-18 hours. After drying, it is cut into sizes that meet the specifications to obtain rod-shaped activated carbon materials.

[0023] Furthermore, in step S2, the solid-liquid ratio of the dry mix to water is 1:5-10.

[0024] Beneficial effects of the present invention:

[0025] (1) The present invention uses nano-scale activated carbon as the adsorption material, and utilizes the high specific surface area and rich pore structure of the nano-scale activated carbon material, which is beneficial to fully expose the active adsorption sites of the activated carbon material, and on the other hand, it can also increase the heavy metal ion storage sites of the activated carbon material, thereby promoting the removal of Pb in sewage. 2+ 、Cu 2+ 、Ni 2+ The physical adsorption of heavy metal ions and activated carbon materials is enhanced, so it has a higher heavy metal ion adsorption capacity.

[0026] (2) The present invention first oxidizes the activated carbon material and chlorinates it, and then connects 1,3-diepoxyglycerol ether glycerol to the surface of the activated carbon material through a chemical reaction. Since 1 equivalent of 1,3-diepoxyglycerol ether glycerol contains 2 equivalents of epoxy groups, 1 equivalent of acyl chloride group on the surface of the activated carbon material can introduce 2 equivalents of epoxy groups, thereby improving the grafting rate of further reactions. Then, 1,3-diaminothiourea is modified on the surface of the activated carbon material through an amino-epoxy ring-opening addition reaction. Since a large number of N and S donor atoms in the aminothiourea group contain coordinated electrons, they can react with Pb in the wastewater. 2+ 、Cu 2+ 、Ni 2+ At the same time, the hydroxyl groups produced by the ring-opening reaction can produce a chelating effect with the heavy metal ions in the wastewater, thereby combining physical adsorption and chemical adsorption to further enhance the heavy metal ion adsorption performance of the activated carbon material and show a higher adsorption capacity.

[0027] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. DETAILED DESCRIPTION

[0028] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0029] In the following examples, the preparation method of functionalized activated carbon particles is as follows:

[0030] ① Place 5g of activated carbon in concentrated nitric acid and reflux at 100℃ for 2h. Use deionized water to wash the reaction product until it is neutral and then dry it. Place the product after the post-treatment process in 80mL of thionyl chloride, stir it evenly, add 1mL of N,N-dimethylformamide dropwise, and react at 75℃ for 48h to obtain acyl chloride-modified activated carbon.

[0031] ②Ultrasonic dispersion of 2 g of acyl chloride modified activated carbon material in tetrahydrofuran solvent, add 0.6 g of 1,3-diepoxyglycerol ether glycerol, stir well, place the reaction system at 70 ° C, react for 12 hours, filter and separate the solid sample after the reaction, wash the product with deionized water, and vacuum dry to obtain epoxy modified activated carbon, weigh 0.2 g of epoxy modified activated carbon and pour it into toluene, ultrasonically disperse it to form a uniform dispersion, measure 15 mL of hydrochloric acid-acetone solution with a volume ratio of 1:80, pour it into the dispersion, increase the temperature to 70 ° C, react for 2 hours, and titrate with a potassium hydroxide ethanol solution with a concentration of 0.1 mol / L until the solution changes color. The formula Calculate the epoxy value, where m is the mass of the sample, V is the volume of the potassium hydroxide ethanol solution consumed in the titration sample, V0 is the volume of the potassium hydroxide ethanol solution consumed in the blank experiment, C is the concentration of the potassium hydroxide ethanol solution, and T is the epoxy value. After testing, the epoxy value of the epoxy-modified activated carbon is 0.39 mol / 100g;

[0032] ③ Add 1 g of epoxy-modified activated carbon to N,N-dimethylformamide, ultrasonically disperse at 200 W power for 30 minutes, add 0.5 g of 1,3-diaminothiourea and 50 mL of 1 mol / L sodium hydroxide solution, stir well, place the system at 80 ° C, stir and react for 16 hours, filter and collect the filter cake after the reaction, wash the filter cake with deionized water to a pH of 7, vacuum dry, grind and crush to obtain functionalized activated carbon particles, and test the epoxy value of the functionalized activated carbon particles in the same way as step ②. After testing, the epoxy value of the functionalized activated carbon particles is 0.17 mol / 100 g. Compared with the epoxy-modified activated carbon, the epoxy value of the functionalized activated carbon particles is reduced. It is speculated that this is because 1,3-diaminothiourea reacts with the epoxy groups of the epoxy-modified activated carbon, consuming some of the epoxy groups.

[0033] Example 1

[0034] Preparation of rod-shaped activated carbon materials

[0035] S1: 60 parts of functionalized activated carbon particles, 5 parts of carboxymethyl cellulose and 1 part of diatomaceous earth were poured into a mixer and dry-mixed at a speed of 60 rpm to obtain a dry mix;

[0036] S2: adding water to the dry mix prepared in step S1 at a solid-liquid ratio of 1:5, and wet mixing at a rotation speed of 20 rpm to obtain a wet mix;

[0037] S3: The wet mixture prepared in step S2 is compressed and compacted to remove moisture, dried at 20°C for 24 hours after compression, and then kneaded into cylindrical activated carbon rods using a kneader;

[0038] S4: The cylindrical activated carbon rod prepared in S3 is placed in a vacuum drying oven at 40°C and dried for 6 hours. After drying, it is cut into sizes that meet the specifications to obtain rod-shaped activated carbon materials.

[0039] Example 2

[0040] Preparation of rod-shaped activated carbon materials

[0041] S1: Pour 70 parts of functionalized activated carbon particles, 10 parts of carboxymethyl cellulose and 2 parts of diatomaceous earth into a mixer and dry-mix at a speed of 80 rpm to obtain a dry mix;

[0042] S2: adding water to the dry mix prepared in step S1 at a solid-liquid ratio of 1:8, and wet mixing at a rotation speed of 30 rpm to obtain a wet mix;

[0043] S3: The wet mixture prepared in step S2 is compressed and compacted to remove moisture, dried at 30°C for 30 hours after compression, and then kneaded into cylindrical activated carbon rods using a kneader;

[0044] S4: The cylindrical activated carbon rod prepared in S3 is placed in a vacuum drying oven at 45°C and dried for 12 hours. After drying, it is cut into sizes that meet the specifications to obtain rod-shaped activated carbon materials.

[0045] Example 3

[0046] Preparation of rod-shaped activated carbon materials

[0047] S1: 80 parts of functionalized activated carbon particles, 15 parts of carboxymethyl cellulose and 5 parts of diatomaceous earth were poured into a mixer and dry-mixed at a speed of 100 rpm to obtain a dry mix;

[0048] S2: adding water to the dry mix prepared in step S1 at a solid-liquid ratio of 1:10, and wet mixing at a rotation speed of 40 rpm to obtain a wet mix;

[0049] S3: The wet mixture prepared in step S2 is compressed and compacted to remove moisture, dried at 35°C for 36 hours after compression, and then kneaded into cylindrical activated carbon rods using a kneader;

[0050] S4: The cylindrical activated carbon rod prepared in S3 is placed in a vacuum drying oven at 50°C and dried for 18 hours. After drying, it is cut into sizes that meet the specifications to obtain rod-shaped activated carbon materials.

[0051] Comparative Example 1

[0052] Preparation of rod-shaped activated carbon materials

[0053] S1: Pour 70 parts of activated carbon, 10 parts of carboxymethyl cellulose and 2 parts of diatomaceous earth into a mixer, and dry mix them at a speed of 80 rpm to obtain a dry mix;

[0054] S2: adding water to the dry mix prepared in step S1 at a solid-liquid ratio of 1:8, and wet mixing at a rotation speed of 30 rpm to obtain a wet mix;

[0055] S3: The wet mixture prepared in step S2 is compressed and compacted to remove moisture, dried at 30°C for 30 hours after compression, and then kneaded into cylindrical activated carbon rods using a kneader;

[0056] S4: The cylindrical activated carbon rod prepared in S3 is placed in a vacuum drying oven at 45°C and dried for 12 hours. After drying, it is cut into sizes that meet the specifications to obtain rod-shaped activated carbon materials.

[0057] Performance testing:

[0058] Weigh 0.4 g of the rod-shaped activated carbon material prepared in Examples 1 to 3 and Comparative Example 1, add it to 500 mL of a 300 mg / L lead nitrate solution, disperse it evenly, transfer it to a shaker for oscillation adsorption, adjust the solution pH to 5, set the temperature to 25 ° C, the oscillation frequency to 180 rpm, and the adsorption time to 6 h. After the adsorption is completed, filter it, and use an Avio 220Max atomic absorption spectrophotometer to test the Pb content in the filtrate. 2+ The concentration of , calculate the adsorption capacity, the test results are shown in the table below;

[0059]

[0060] It can be concluded from the data in the table that the rod-shaped activated carbon materials prepared in Examples 1 to 3 of the present invention have a high heavy metal ion adsorption capacity, indicating that they have excellent heavy metal ion adsorption performance, while the rod-shaped activated carbon material prepared in Comparative Example 1 uses unmodified activated carbon as the main material, and has a lower adsorption capacity. It is speculated that this is because the unmodified activated carbon material can only adsorb heavy metal ions through physical action, and therefore does not have a high heavy metal ion adsorption performance.

[0061] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0062] The above content is merely an example and explanation of the concept of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined by the claims, they should all fall within the scope of protection of the present invention.

Claims

1. A rod-shaped activated carbon material, characterized in that: The method comprises the following raw materials in parts by weight: 60-80 parts of functionalized activated carbon particles, 5-15 parts of carboxymethyl cellulose, and 1-5 parts of diatomaceous earth; The functionalized activated carbon particles are prepared by oxidizing the surface of activated carbon, then introducing epoxy groups, and then grafting thiosemicarbazide groups; The production process of the functionalized activated carbon particles is specifically as follows: ① Place the activated carbon in concentrated nitric acid and reflux at 90-100°C for 1-3 hours. Use deionized water to wash the reaction product until it is neutral and then dry it. Place the product after the post-treatment process in thionyl chloride, stir it evenly, add N,N-dimethylformamide dropwise, and react at 70-80°C for 24-48 hours to obtain acyl chloride-modified activated carbon; ②Ultrasonic dispersion of the acyl chloride modified activated carbon material in an organic solvent, adding 1,3-diepoxyglycerol ether glycerol, stirring evenly, placing the reaction system at a temperature of 60-80°C, reacting for 6-18 hours, filtering and separating the solid sample after the reaction, washing the product with deionized water, and vacuum drying to obtain epoxy modified activated carbon; ③ Add epoxy-modified activated carbon to N,N-dimethylformamide, ultrasonically disperse, add 1,3-diaminothiourea and sodium hydroxide solution, stir evenly, place the system at 70-90°C, stir and react for 12-24 hours, filter and collect the filter cake after the reaction is completed, wash the filter cake, vacuum dry, and grind to obtain functionalized activated carbon particles.

2. The rod-shaped activated carbon material according to claim 1, characterized in that: In step ②, the organic solvent is any one of tetrahydrofuran, 1,4-dioxane or chloroform.

3. The rod-shaped activated carbon material according to claim 1, characterized in that: In step ②, the mass ratio of the acyl chloride modified activated carbon material to 1,3-diepoxyglyceryl ether glycerol is 1:0.2-0.

6.

4. The rod-shaped activated carbon material according to claim 1, characterized in that: In step ③, the ultrasonic power during the ultrasonic dispersion is 200-400 W, and the ultrasonic time is 20-40 min.

5. The rod-shaped activated carbon material according to claim 1, characterized in that: In step ③, the concentration of the sodium hydroxide solution is 0.5-1.5 mol / L.

6. The rod-shaped activated carbon material according to claim 1, characterized in that: In step ③, during the washing, the filter cake is washed with deionized water until the pH value is 6-7.

7. A process for producing a rod-shaped activated carbon material according to any one of claims 1 to 6, characterized in that: The production process comprises the following steps: S1: Pour the functionalized activated carbon particles, carboxymethyl cellulose and diatomaceous earth into a mixer and dry-mix them at a speed of 60-100 rpm to obtain a dry mix; S2: adding water to the dry mix prepared in step S1, and wet mixing at a rotation speed of 20-40 rpm to obtain a wet mix; S3: Compressing and compacting the wet mixture prepared in step S2 to remove moisture, drying it at 20-35°C for 24-36 hours, and kneading it into cylindrical activated carbon rods using a kneader; S4: The cylindrical activated carbon rod prepared in S3 is placed in a vacuum drying oven at 40-50°C and dried for 6-18 hours. After drying, it is cut into sizes that meet the specifications to obtain rod-shaped activated carbon materials.

8. The production process of a rod-shaped activated carbon material according to claim 7, characterized in that: In step S2, the solid-liquid ratio of the dry mix to water is 1:5-10.

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