CN116375031A - Low-temperature activated carbon, preparation method and application - Google Patents

Abstract

The invention provides a low-temperature activated activated carbon, preparation method and application, which belong to the field of activated carbon nanomaterials. The raw materials used are common and easy-to-obtain industrial-grade products. The equipment is simple, the preparation process is simple, and the repeatability is strong, which is beneficial to industrialized large-scale production. . The low-temperature activated activated carbon provided by the invention has a relatively low activation temperature, and the activator has relatively little corrosion on equipment, which not only further reduces the cost of the product, but also is friendly to the human body and the environment, and can be widely used in water treatment, chemical industry, etc. Catalyst and carrier, solvent recovery, oil decolorization, air purification and other fields. Compared with the existing commercially available activated carbon, the product prepared by the invention has larger specific surface area, more developed pore structure and less iron content in the product. In addition, the product of the present invention can be used in the fields of adsorption of heavy metal ions in aqueous solution, purification of automobile exhaust, impurity removal of printing ink, gas separation, electrode materials for supercapacitors and other electrochemical energy storage materials.

Description

A kind of low-temperature activated activated carbon, preparation method and application

technical field

The invention belongs to the field of activated carbon nanomaterials, in particular to a low-temperature activated activated carbon, a preparation method and an application.

Background technique

Activated carbon is a black porous solid material, the main component is carbon, and contains a small amount of oxygen, hydrogen, sulfur, nitrogen, chlorine and other elements. Because of its rich pore structure and huge specific surface area, and without any toxic side effects and secondary pollution, it is currently recognized as an efficient adsorption material in the world, which can effectively absorb harmful gases and odors. In the treatment of indoor pollution, activated carbon is also used. It is considered to be one of the most environmentally friendly treatment products. In addition, activated carbon also has catalytic, flexible, wear-resistant, conductive and other characteristics, and is widely used in water treatment, chemical catalysts and carriers, gas purification, solvent recovery, oil decolorization, gold extraction, tail liquid recovery, automobile exhaust purification, printing ink impurity removal, gas separation, electrochemical energy storage materials and other fields.

For example, the Chinese invention patent CN202110058052.4 uses the continuous rigid biphenyl structure in the triazine-based cross-linked microporous polymer molecular chain as a carbon source, and the triazine ring structure as a nitrogen source, and is prepared by high-temperature carbonization and potassium hydroxide pore activation. A nitrogen-rich porous activated carbon adsorbent derived from a microporous polymer exhibits excellent pore adsorption properties for heavy metal ions such as Cu ²⁺ . Chinese patent CN202110846095.9 discloses a method for preparing activated carbon using straw as a raw material. In this method, zinc oxide is used as an activator. First, the straw particles and zinc oxide are heated and reacted in a nitrogen atmosphere, and then phosphoric acid is added to carbonize at high temperature. After treatment with hydrochloric acid, activated carbon with good adsorption properties was prepared. Chinese invention patent CN201510868434.8 provides a kind of KOH solid activation to prepare activated carbon. In this method, the KOH solid is first ground into powder, then the activated carbon precursor is added, and it is calcined and carbonized at a high temperature of 700-1000°C under a nitrogen atmosphere, and finally washed with water. and dry. Although the activated carbon prepared by the above-mentioned patent is of good quality, the use of zinc oxide or KOH as the activator makes the reaction temperature too high, the reaction process consumes a lot of energy, and KOH corrodes the equipment more seriously.

Contents of the invention

The purpose of the present invention is to overcome the above-mentioned shortcoming of prior art, provide a kind of low-temperature activated activated carbon, preparation method and application.

In order to achieve the above object, the present invention adopts the following technical solutions to achieve:

A preparation method of activated carbon at low temperature, comprising the following steps:

1) Add the polymer precursor and benzoyl peroxide into hydrochloric acid with a mass fraction of 3.5% according to the molar ratio of 1: (0.1-0.6), and then add hexadecyldimethylethylammonium bromide to obtain a reaction solution , reacting the reaction solution at 0-3°C for 4-12 hours, after the reaction, collecting the solid product for washing and drying;

2) Pre-carbonize the dried product in a nitrogen atmosphere at a temperature of 380-480°C for 1-1.5 hours, and then grind the product;

3) The product and the activator are uniformly mixed according to the mass ratio of 1: (0.8-1.8), and calcined under a nitrogen atmosphere, the calcining temperature is 380-550 °C, and the calcining time is 1.5-2 hours. After the calcining is completed, the The collected solid product is acid-washed and washed with water in sequence, and then dried to obtain an activated carbon product.

Further, the polymer precursor described in step (1) is vinylpyrrolidone, pyrrole, methyl acrylate, ethyl acrylate, 2-methyl methacrylate, 2-ethyl methacrylate, acrylamide, methyl Acrylamide, dimethylaminopropylacrylamide, aniline, p-chloroaniline, 2-fluoroaniline, 4-fluoroaniline, methylaniline or 2-ethylaniline.

Further, the concentration of benzoyl peroxide in the reaction solution in step (1) is 0.1-0.5 mol/L.

Further, the concentration of cetyl dimethyl ethyl ammonium bromide is 0.01-0.1 mol/L.

Further, in step (3), the activator is disodium carbamoyl phosphate, sodium sulfamate, sodium sulfamate, sodium diformamide or potassium sulfamate.

A low-temperature activated activated carbon is prepared according to the above-mentioned method.

Furthermore, it is in the shape of a nano ring.

Further, a large number of micropores and mesopores are distributed in the low-temperature activated carbon.

Further, it can be used as an adsorption material for the adsorption of heavy metal ions in aqueous solution, the purification of automobile exhaust, the removal of impurities and gas separation of printing inks; or/and

As supercapacitor electrode material or energy storage material.

Compared with the prior art, the present invention has the following beneficial effects:

The invention provides a low-temperature activated activated carbon, its preparation method and application. The raw materials used are common and readily available industrial-grade products, the equipment is simple, the preparation process is simple and repeatable, and it is beneficial to large-scale industrial production.

The low-temperature activated carbon provided by the invention has a relatively low activation temperature, and the activator has relatively little corrosion on equipment, which not only further reduces the cost of the product, but also is friendly to the human body and the environment, and can be widely used in water treatment, chemical industry, etc. Catalyst and carrier, solvent recovery, oil decolorization, air purification and other fields. Compared with the existing commercially available activated carbon, the present invention also has the following beneficial effects, the specific surface area of the product is larger, the pore structure is more developed, and the iron content of the product is less. In addition, the product prepared by the present invention has a distinctive appearance and is in the shape of a ring. The diameter of the ring is about 200nm, and the diameter of a single product is about 50nm. The overall product has a relatively obvious pore structure and can also be used for the adsorption of heavy metal ions in aqueous solutions. , automobile exhaust purification, printing ink impurity removal, gas separation, supercapacitor electrode materials and other electrochemical energy storage materials and other fields.

Description of drawings

Fig. 1 is a kind of gac scanning electron micrograph of embodiment 1;

Fig. 2 is a kind of gac transmission electron microscope figure of embodiment 1;

Fig. 3 is a kind of gac XRD figure of embodiment 1;

Fig. 4 is a kind of activated carbon nitrogen isothermal adsorption-desorption curve of embodiment 1;

Fig. 5 is the performance test that the present invention prepares product to be used for supercapacitor;

Table 1 compares the gac product prepared by the present invention with the commercially available product;

Table 2 is the adsorption test of the products prepared by the present invention on Cu ²⁺ in aqueous solution.

Detailed ways

In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only It is an embodiment of a part of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

It should be noted that the terms "first" and "second" in the description and claims of the present invention and the above drawings are used to distinguish similar objects, but not necessarily used to describe a specific sequence or sequence. It is to be understood that the data so used are interchangeable under appropriate circumstances such that the embodiments of the invention described herein can be practiced in sequences other than those illustrated or described herein. Furthermore, the terms "comprising" and "having", as well as any variations thereof, are intended to cover a non-exclusive inclusion, for example, a process, method, system, product or device comprising a sequence of steps or elements is not necessarily limited to the expressly listed instead, may include other steps or elements not explicitly listed or inherent to the process, method, product or apparatus.

The present invention is described in further detail below in conjunction with accompanying drawing:

Example 1

Add methyl acrylate and benzoyl peroxide into 100 mL of hydrochloric acid with a mass fraction of 3.5% in a molar ratio of 1:0.6, the concentration of benzoyl peroxide in the mixed solution is 0.5 mol/L, and then add hexadecyl dimethyl Ammonium ethyl ammonium bromide, the concentration is 0.1mol/L, and stirred to make it react at normal pressure 3°C for 12 hours, after the reaction, the collected solid product was washed 3 times with deionized water, and heated Tumble dry. The dried product is pre-carbonized under a nitrogen atmosphere, the treatment temperature is 480° C., and the treatment time is 1.5 hours, and then the product is ground for 1.5 hours; the above product and carbamoyl phosphate disodium salt are in a mass ratio of 1: 1.8 Mix evenly and perform calcination under a nitrogen atmosphere. The calcination temperature is 550°C and the calcination time is 2 hours. After the calcination is completed, the collected solid product is washed 3 times with dilute hydrochloric acid and deionized water, and dried to obtain an activated carbon product.

Referring to Fig. 1, Fig. 1 is a scanning electron microscope image of a kind of activated carbon prepared in Example 1, the product has distinctive features, and is circular, and the diameter of the circular ring is about 200nm, and the diameter of a single product is about 50nm, and the overall product has a relatively Obvious pore structure.

Referring to FIG. 2, FIG. 2 is a transmission electron microscope image of the product of Example 1, and it can be determined that the product is a typical amorphous carbon material.

Referring to Fig. 3, Fig. 3 is the XRD figure of the product of embodiment 1, can confirm that the main component of product is carbon material by XRD figure.

Referring to Fig. 4, Fig. 4 is the nitrogen isothermal adsorption-desorption curve of the product of Example 1, the curve is a typical I-type curve, and at a lower relative pressure, the amount of nitrogen adsorption rises sharply, indicating that there are a large number of micropores in the product. The product curve is convex, indicating that there is a certain amount of mesopores in the product.

Referring to Fig. 5, Fig. 5 is the electrochemical performance test figure of the product of embodiment 1. The prepared product was used as the working electrode of the supercapacitor, the platinum sheet was used as the counter electrode, the mercury/mercury oxide was used as the reference electrode, and the 6M KOH solution was used as the electrolyte to conduct constant current charge and discharge tests. Figure 5a shows that the specific discharge capacity of the product can reach 470F/g at 1.0A/g. Figure 5b shows that the capacity retention rate of the product can reach 81% after 10,000 constant current charge and discharge cycles at 10A/g.

Referring to Table 1, Table 1 is a comparison between the product prepared by the present invention and the commercially available product. By comparison, it is found that the product prepared by the present invention has a larger specific surface area, more developed pore structure, and less iron content than the commercially available product.

The product prepared by the present invention is compared with the commercially available product in table 1

Referring to Table 2, Table 2 is the adsorption test of Cu ²⁺ in aqueous solution by the products prepared in the present invention. First prepare 100mg/L of Cu ²⁺ standard solution with deionized water and copper nitrate, add 150mg of the product prepared by the present invention, carry out adsorption after stirring for 4h, use the ultraviolet-visible light spectrophotometer to detect the concentration of Cu ²⁺ , and calculate The adsorption rate of the product on Cu ²⁺ .

Table 2 The preparation product of the present invention is to the adsorption test of Cu ²⁺

Example 2

Add ethyl acrylate and benzoyl peroxide into 60 mL of hydrochloric acid with a mass fraction of 3.5% in a molar ratio of 1:0.1, the concentration of benzoyl peroxide in the mixed solution is 0.1 mol/L, and then add cetyl dimethyl ethyl ethylammonium bromide, the concentration is 0.01mol/L, and stirred to make it react at normal pressure 0°C for 4 hours, after the reaction, the collected solid product was washed 3 times with deionized water, and Tumble dry. Pre-carbonize the dried product under a nitrogen atmosphere at a temperature of 380°C for 1 hour, then grind the product for 1 hour; mix the above product with sodium sulfamate in a mass ratio of 1:0.8 , calcined under a nitrogen atmosphere, the calcining temperature is 380 ° C, and the calcining time is 1.5 hours. After the calcining is completed, the collected solid product is washed three times with dilute hydrochloric acid and deionized water, and the activated carbon product is obtained after drying.

Example 3

Add methacrylamide and benzoyl peroxide into 90mL of hydrochloric acid with a mass fraction of 3.5% according to the molar ratio of 1:0.5, the concentration of benzoyl peroxide in the mixed solution is 0.4mol/L, and then add hexadecyl di Methyl ethyl ammonium bromide, the concentration is 0.09mol/L, and stirred to make it react at normal pressure 2 ℃ for 11 hours, after the reaction, the collected solid product was washed 3 times with deionized water, and the Dry at ℃. Pre-carbonize the dried product under a nitrogen atmosphere at a temperature of 480°C for 1.5 hours, then grind the product for 1 hour; mix the above product and sodium sulfanilate in a mass ratio of 1:1.8 Mixing and calcining under a nitrogen atmosphere, the calcining temperature is 500°C, and the calcining time is 2 hours. After the calcining is completed, the collected solid product is washed three times with dilute hydrochloric acid and deionized water, and the activated carbon product is obtained after drying.

Example 4

Add dimethylaminopropylacrylamide and benzoyl peroxide into 80mL hydrochloric acid with a mass fraction of 3.5% according to the molar ratio of 1:0.4, the concentration of benzoyl peroxide in the mixed solution is 0.4mol/L, and then add ten Hexaalkyldimethylethylammonium bromide, the concentration is 0.08mol/L, and stirred to make it react at normal pressure 3°C for 10 hours. After the reaction, the collected solid product is washed 3 times with deionized water , and dried at 80°C. Pre-carbonize the dried product under a nitrogen atmosphere at a temperature of 480°C for 1.5 hours, then grind the product for 1 hour; mix the above product and potassium sulfamate evenly at a mass ratio of 1:1.8 , in a nitrogen atmosphere for calcination, the calcination temperature is 550 ° C, and the calcination time is 2 hours. After the calcination is completed, the collected solid product is washed 3 times with dilute hydrochloric acid and deionized water, and dried to obtain an activated carbon product.

Methyl acrylate, ethyl acrylate, methacrylamide and dimethylaminopropyl acrylamide in embodiment 1-embodiment 4 can be replaced by vinylpyrrolidone, pyrrole, 2-methyl methacrylate, 2-methacrylic acid ethyl acrylate, acrylamide, aniline, p-chloroaniline, 2-fluoroaniline, 4-fluoroaniline, methylaniline and 2-ethylaniline.

The above content is only to illustrate the technical ideas of the present invention, and cannot limit the protection scope of the present invention. Any changes made on the basis of the technical solutions according to the technical ideas proposed in the present invention shall fall within the scope of the claims of the present invention. within the scope of protection.

Claims (9)

1. The preparation method of the low-temperature activated carbon is characterized by comprising the following steps of:

1) The polymer precursor and benzoyl peroxide are mixed according to a mole ratio of 1: (0.1-0.6) adding into hydrochloric acid with the mass fraction of 3.5%, then adding hexadecyl dimethyl ethyl ammonium bromide to obtain a reaction solution, reacting the reaction solution at the temperature of 0-3 ℃ for 4-12 hours, and collecting a solid product for washing and drying after the reaction is finished;

2) Pre-carbonizing the dried product in nitrogen atmosphere at 380-480 ℃ for 1-1.5 hours, and grinding the product;

3) Uniformly mixing the product with an activator according to the mass ratio of 1 (0.8-1.8), calcining under the nitrogen atmosphere at the calcining temperature of 380-550 ℃ for 1.5-2 hours, and after the calcining, sequentially carrying out acid washing and water washing on the collected solid product, and drying to obtain the active carbon product.

2. The method for preparing activated carbon at low temperature according to claim 1, wherein the polymer precursor in the step (1) is vinyl pyrrolidone, pyrrole, methyl acrylate, ethyl acrylate, 2-methyl methacrylate, 2-ethyl methacrylate, acrylamide, methacrylamide, dimethylaminopropyl acrylamide, aniline, p-chloroaniline, 2-fluoroaniline, 4-fluoroaniline, methylaniline or 2-ethylaniline.

3. The method for producing a low-temperature activated carbon according to claim 1, wherein the concentration of benzoyl peroxide in the reaction liquid in the step (1) is 0.1 to 0.5mol/L.

4. The method for preparing low-temperature activated carbon according to claim 1, wherein the concentration of hexadecyldimethyl ethyl ammonium bromide is 0.01-0.1 mol/L.

5. The method for preparing low-temperature activated carbon according to claim 1, wherein in the step (3), the activator is carbamyl disodium phosphate, sodium sulfamate, sodium dicarboxamide or potassium sulfamate.

6. A low temperature activated carbon prepared according to the method of any one of claims 1 to 5.

7. The activated carbon of claim 6, wherein the activated carbon is in the form of a nanoring.

8. The activated carbon of claim 6, wherein said activated carbon comprises a plurality of micropores and mesopores.

9. The use of a low temperature activated carbon as claimed in claim 6, 7 or 8 as an adsorbent for the adsorption of heavy metal ions in aqueous solutions, purification of automobile exhaust gases, removal of impurities from printing inks and gas separation; or/and (or)

As supercapacitor electrode material or energy storage material.

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