Phenolic resin-based spherical activated carbon as well as preparation method and application thereof

Abstract

The invention discloses phenolic resin-based spherical activated carbon and a preparation method and application thereof.The preparation method comprises the steps that raw materials containing linear phenolic resin, a curing agent and an organic solvent are mixed to obtain a mixed solution, the mixed solution is dropped into a hot oil column, and thermosetting phenolic resin balls are obtained through crosslinking, curing, balling and drying; and further performing high-temperature carbonization to obtain the phenolic resin-based spherical activated carbon. The preparation method disclosed by the invention is simple and can be continuously operated. The obtained spherical activated carbon is uniform in size, and the size can be controlled and adjusted within the range of 0.5-2.5 mm.

Description

Technical Field

[0001] The present application relates to a phenolic resin-based spherical activated carbon and a preparation method and application thereof, belonging to the field of activated carbon materials. Background Art

[0002] Spherical activated carbon is a new type of high-performance activated carbon with a smooth surface. It has unique properties such as high purity, low ash powder, high strength, high wear resistance, high fluidity and narrow particle size distribution. Therefore, it has broad application prospects in the fields of solvent recovery, gas purification, water treatment, etc. For example, spherical activated carbon has been used in the fields of adsorption materials for clean room filters in the semiconductor industry, gas treatment of electronic devices, etc. In addition, due to its good physiological solubility, spherical activated carbon also has important applications in medical and health fields such as blood purification.

[0003] Spherical activated carbon can be divided into three types according to raw materials: asphalt-based spherical activated carbon, coal-based spherical activated carbon and polymer-based spherical activated carbon. Among them, coal-based spherical activated carbon is prepared by rotary ball making method with pulverized coal as the main raw material. However, coal-based spherical activated carbon has the problems of high ash content and poor mechanical strength, and the difference in properties of different types of coal will lead to unstable properties of the produced spherical activated carbon.

[0004] Asphalt-based spherical activated carbon is made from asphalt as raw material and is prepared through modulation, spheroidization, infusibility, carbonization and activation. It is one of the high value-added products of asphalt. The spheroidization process of asphalt will directly affect the sphericity, surface morphology, mechanical strength and other properties of the final spherical activated carbon, and is the most critical preparation process. The main ball-forming methods include suspension method, emulsification method, disc ball-forming method and spray method. However, the asphalt balls obtained after spheroidization are a thermoplastic material, and the fluidity during heating will lead to the destruction of the macroscopic spherical morphology. Therefore, it is necessary to first use an oxidation infusibility process (mainly including gas phase oxidation, liquid phase oxidation and mixed oxidation) to convert the asphalt balls into a thermosetting material, but this process is time-consuming and energy-intensive.

[0005] The raw materials of polymer-based spherical activated carbon mainly include phenolic resin and ion exchange resin. Compared with ion exchange resin, phenolic resin has the characteristics of low ash content and high carbonization yield. In particular, thermosetting phenolic resin can be directly carbonized to prepare spherical activated carbon without the time-consuming and energy-consuming oxidation and infusibility process, so it has attracted widespread attention.

[0006] At present, phenolic resin-based spherical activated carbon is mainly spheroidized by emulsion method or suspension method, but the process conditions are complex and it is difficult to produce continuously. The resulting spherical activated carbon has a wide particle size distribution, the particle size is uncontrollable, and it is difficult to prepare large-sized spherical activated carbon larger than 1 mm. Summary of the invention

[0007] The present application provides a method for preparing phenolic resin-based spherical activated carbon, wherein a raw material containing a linear phenolic resin, a curing agent, a forming agent, and a solvent is dripped into a hot oil column, the droplets are solidified into balls in the oil column, and then further subjected to high-temperature carbonization and activation to obtain phenolic resin-based spherical activated carbon, thereby solving the problem in the prior art that "the process conditions in the synthesis of phenolic resin-based spherical activated carbon are complex, making it difficult to carry out continuous production, the particle size distribution of the obtained spherical activated carbon is relatively wide, the particle size is uncontrollable, and it is difficult to prepare large-sized spherical activated carbon of more than 1 mm".

[0008] This application adopts the following technical solutions:

[0009] A method for preparing phenolic resin-based spherical activated carbon comprises the following steps:

[0010] S1, dripping a mixed solution containing a linear phenolic resin, a curing agent, a forming agent, and a solvent into a hot oil column, so that the mixed solution droplets solidify into balls in the oil column, and then taking out and drying to obtain thermosetting phenolic resin balls;

[0011] S2. Carbonizing and activating the thermosetting phenolic resin balls obtained in step S1 to obtain the phenolic resin-based spherical activated carbon.

[0012] Optionally, in step S1, the oil in the hot oil column is selected from at least one of kerosene, vegetable oil, white oil, transformer oil, and liquid paraffin;

[0013] The temperature of the hot oil column is 80-180°C.

[0014] Optionally, in step S1, the curing agent is selected from at least one of hexamethylenetetramine, urea and melamine.

[0015] Optionally, in step S1, the relative molecular weight of the linear phenolic resin is 200-2000.

[0016] Optionally, in step S1, the molding agent is selected from at least one of Tween 20, Span 80, polyvinyl pyrrolidone and peregal.

[0017] Optionally, in step S1, the solvent is selected from at least one of ethanol, ethylene glycol, N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and 1,4-dioxane.

[0018] Optionally, in step S1, the weight ratio of the linear phenolic resin, the curing agent, the molding agent and the solvent in the mixed liquid is 1:(0.01-0.5):(0.001-0.1):(0.05-1).

[0019] Optionally, the mass ratio of the curing agent to the linear phenolic resin is selected from any value of 0.01:1, 0.05:1, 0.1:1, 0.15:1, 0.2:1, or any range therebetween.

[0020] Optionally, the mass ratio of the molding agent to the linear phenolic resin is selected from any value among 0.001:1, 0.005:1, 0.01:1, 0.02:1, 0.03:1, 0.04:1, 0.05:1, 0.06:1, 0.07:1, 0.08:1, 0.09:1, 0.1:1 or any range value therebetween.

[0021] Optionally, the mass ratio of the linear phenolic resin to the solvent is selected from any value of 0.05:1, 0.1:1, 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1 or any range therebetween.

[0022] Optionally, in step S1, the drying conditions are: the drying temperature is 80 to 200° C., and the drying time is 1 to 24 hours.

[0023] Optionally, in step S2, the carbonization conditions are: the carbonization temperature is 500-1000°C, the carbonization time is 1-10 hours, and the carbonization atmosphere is an inert gas atmosphere.

[0024] Optionally, the inert gas is selected from at least one of nitrogen, argon and helium.

[0025] According to another aspect of the present application, a phenolic resin-based spherical activated carbon is provided, wherein the phenolic resin-based spherical activated carbon is prepared by the above-mentioned preparation method;

[0026] The average particle size of the phenolic resin-based spherical activated carbon is 0.5 to 2.5 mm.

[0027] The average particle size of the phenolic resin-based spherical activated carbon is selected from any value among 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, or any range between the two.

[0028] According to another aspect of the present application, there is also provided an application of the above-mentioned phenolic resin-based spherical activated carbon in the fields of gas purification, water purification, blood purification, and catalyst carrier.

[0029] The beneficial effects of this application include:

[0030] The preparation method of phenolic resin-based spherical activated carbon provided in the present application is simple and can be operated continuously; spherical activated carbon with a particle size of more than 1 mm can be prepared, and the obtained spherical activated carbon has a uniform size and a controllable particle size. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a physical photo of the spherical activated carbon obtained in Example 1.

[0032] Figure 2 This is a physical photo of the spherical activated carbon obtained in Example 6. DETAILED DESCRIPTION

[0033] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0034] Unless otherwise specified, the raw materials in the examples of this application were purchased through commercial channels.

[0035] Example 1

[0036] S1: 10 g of a linear phenolic resin having an average relative molecular weight of 600, 0.8 g of hexamethylenetetramine and 0.02 g of Tween-20 were dissolved in 20 g of ethanol to obtain a uniform transparent solution;

[0037] S2: dropping the above solution into a hot oil column of 120°C kerosene, so that the resin solution shrinks into a ball due to interfacial tension and solidifies into a ball during the slow falling process;

[0038] S3: Collect the resin balls at the bottom of the oil column, cool them to room temperature, and dry them at 120°C to obtain dry resin balls;

[0039] S4: Place the resin dry ball in a nitrogen atmosphere, increase the temperature to 800°C at a heating rate of 5°C / min, and keep the temperature constant for 2 hours to obtain spherical activated carbon.

[0040] Figure 1 This is a photo of the spherical activated carbon obtained in Example 1. The average particle size is 0.8 mm. It can be seen from the figure that the spherical activated carbon obtained is uniform in size.

[0041] Embodiments 2 to 5

[0042] The process is basically the same as Example 1, except that the ethanol in S1 is replaced by ethylene glycol, DMF, DMSO, and 1,4-dioxane in sequence, and the rest is exactly the same as Example 1.

[0043] The average particle sizes of the spherical activated carbons obtained in Examples 2 to 5 are 0.85 mm, 0.65 mm, 0.7 mm and 1.1 mm, respectively.

[0044] Similar to Example 1, the obtained spherical activated carbon has uniform size.

[0045] Example 6

[0046] It is basically the same as Example 1, except that the curing dosage in S1 is increased to 1.1 g, and the rest is exactly the same as Example 1.

[0047] Figure 2 This is a real photo of the spherical activated carbon obtained in Example 6, with an average particle size of 1.15 mm.

[0048] Similar to Example 1, the obtained spherical activated carbon has uniform size.

[0049] Example 7

[0050] The method is basically the same as Example 1, except that the amounts of linear phenolic resin and hexamethylenetetramine in S1 are adjusted to 15 g and 1.2 g, respectively. The rest is exactly the same as Example 1.

[0051] The average particle size of the spherical activated carbon obtained in Example 7 is 1.6 mm.

[0052] Similar to Example 1, the obtained spherical activated carbon has uniform size.

[0053] Example 8

[0054] The method is basically the same as Example 1, except that the amounts of linear phenolic resin and hexamethylenetetramine in S1 are adjusted to 20 g and 1.5 g, respectively. The rest is exactly the same as Example 1.

[0055] The average particle size of the spherical activated carbon obtained in Example 8 is 2.5 mm.

[0056] Similar to Example 1, the obtained spherical activated carbon has uniform size.

[0057] Examples 9 to 11

[0058] The method is basically the same as Example 1, except that the molding agent in S1 is replaced by Span-80, polyvinyl pyrrolidone and Pingpingjia in sequence from Tween 20, and the rest is exactly the same as Example 1.

[0059] The average particle sizes of the spherical activated carbons obtained in Examples 9 to 11 are 0.8 mm, 0.5 mm and 0.75 mm, respectively.

[0060] Similar to Example 1, the obtained spherical activated carbon has uniform size.

[0061] Embodiments 12 to 13

[0062] The process is basically the same as Example 1, except that the amount of Tween 20 in S1 is adjusted to 0.01 g and 0.1 g respectively, and the rest is exactly the same as Example 1.

[0063] The average particle sizes of the spherical activated carbons obtained in Examples 12 to 13 are 1.05 mm and 0.5 mm, respectively.

[0064] Similar to Example 1, the obtained spherical activated carbon has uniform size.

[0065] Embodiments 14 to 17

[0066] The method is basically the same as Example 1, except that the kerosene in S2 is replaced by vegetable oil, white oil, transformer oil and liquid paraffin in sequence, and the rest is exactly the same as Example 1.

[0067] The average particle sizes of the spherical activated carbons obtained in Examples 14 to 17 are 0.6 mm, 0.76 mm, 0.83 mm, and 0.72 mm, respectively.

[0068] Similar to Example 1, the obtained spherical activated carbon has uniform size.

[0069] Embodiments 18 to 19

[0070] The method is basically the same as Example 1, except that the temperature of the oil in the oil column in S2 is adjusted to 80° C. and 180° C. respectively. The rest is exactly the same as Example 1.

[0071] The average particle sizes of the spherical activated carbons obtained in Examples 18 to 19 were 0.91 mm and 0.82 mm, respectively.

[0072] Similar to Example 1, the obtained spherical activated carbon has uniform size.

[0073] Embodiment 20-21

[0074] The method is basically the same as Example 1, except that the average relative molecular weight of the linear phenolic resin in S1 is replaced by 200 and 1000 respectively, and the rest is exactly the same as Example 1.

[0075] The average particle sizes of the spherical activated carbons obtained in Examples 20 to 21 are 0.61 mm and 1.22 mm, respectively.

[0076] Similar to Example 1, the obtained spherical activated carbon has uniform size.

[0077] Comparative Example 1

[0078] The method is basically the same as Example 1, except that Tween 20, a molding agent, is not added to S1, and the rest is exactly the same as Example 1.

[0079] In Comparative Example 1, only water drop-shaped thermosetting phenolic resin was obtained, and finally only water drop-shaped activated carbon was obtained.

[0080] Comparative Example 2

[0081] The method is basically the same as Example 1, except that the amount of curing agent hexamethylenetetramine in S1 is adjusted to 2.5 g, and the rest is exactly the same as Example 1.

[0082] The viscosity of the mixed solution in Comparative Example 2 is too high, and the tail end of the droplet becomes filaments during the spherical dropping process, and ultimately no spherical activated carbon can be obtained.

[0083] Comparative Example 3

[0084] It is basically the same as Example 1, the only difference is that the temperature of the oil in the hot oil column in S2 is adjusted to 70°C, and the rest is exactly the same as Example 1.

[0085] The mixed solution in Comparative Example 3 could not be solidified in the hot oil column, and ultimately no spherical activated carbon could be obtained.

[0086] Comparative Example 4 Emulsion Method

[0087] S1: Dissolve 10 g of linear phenolic resin and 0.8 g of hexamethylenetetramine in 20 g of ethanol to obtain a uniform transparent solution A;

[0088] S2: 0.02 g of Tween-20 and 200 g of kerosene were added into a round-bottom flask, and stirred at a stirring rate of 300 rpm for 10 min to fully mix the two to obtain solution B;

[0089] S3: Add solution A to solution B at a stirring rate of 300 rpm. Continue stirring for 10 min after the addition is complete, so that the resin solution shrinks into balls due to interfacial tension to form a suspension.

[0090] S4: placing the flask in a heater to heat the mixed liquid in the flask to 120°C and keeping the temperature constant for 30 minutes to solidify the resin into balls;

[0091] S5: Collect the resin balls at the bottom of the oil column, cool them to room temperature, and dry them at 120°C to obtain dry resin balls;

[0092] S6: Place the resin dry ball in a nitrogen atmosphere, raise the temperature to 800°C at a heating rate of 5°C / min, and keep the temperature constant for 2 hours to obtain spherical activated carbon.

[0093] The average particle size of the spherical activated carbon obtained in Comparative Example 4 is 0.25 mm, but the size distribution of the spherical activated carbon obtained is relatively wide, ranging from 0.05 to 0.8 mm.

[0094] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for preparing phenolic resin-based spherical activated carbon, characterized in that: The steps include: S1, dripping a mixed solution containing a linear phenolic resin, a curing agent, a forming agent, and a solvent into a hot oil column, so that the mixed solution droplets solidify into balls in the oil column, and then taking out and drying to obtain thermosetting phenolic resin balls; S2. Carbonizing and activating the thermosetting phenolic resin balls obtained in step S1 to obtain the phenolic resin-based spherical activated carbon.

2. The preparation method according to claim 1, characterized in that: In step S1, the oil in the hot oil column is selected from at least one of kerosene, vegetable oil, white oil, transformer oil, and liquid paraffin; The temperature of the hot oil column is 80-180°C.

3. The preparation method according to claim 1, characterized in that: In step S1, the curing agent is selected from at least one of hexamethylenetetramine, urea, and melamine; Preferably, in step S1, the relative molecular weight of the linear phenolic resin is 200-2000.

4. The preparation method according to claim 1, characterized in that: In step S1, the molding agent is selected from at least one of Tween 20, Span 80, polyvinyl pyrrolidone and peregal.

5. The preparation method according to claim 1, characterized in that: In step S1, the solvent is selected from at least one of ethanol, ethylene glycol, DMF, DMSO, and 1,4-dioxane.

6. The preparation method according to claim 1, characterized in that: In step S1, the weight ratio of the linear phenolic resin, the curing agent, the forming agent and the solvent in the mixed solution is 1:(0.01-0.5):(0.001-0.1):(0.05-1).

7. The preparation method according to claim 1, characterized in that: In step S1, the drying conditions are: the drying temperature is 80-200°C, and the drying time is 1-24h.

8. The preparation method according to claim 1, characterized in that: In step S2, the carbonization conditions are as follows: the carbonization temperature is 500-1000°C, the carbonization time is 1-10 hours, and the carbonization atmosphere is an inert gas atmosphere.

9. A phenolic resin-based spherical activated carbon, characterized in that: The phenolic resin-based spherical activated carbon is prepared by the preparation method according to any one of claims 1 to 8; The average particle size of the phenolic resin-based spherical activated carbon is 0.5 to 2.5 mm.

10. Application of the phenolic resin-based spherical activated carbon according to claim 9 in the fields of gas purification, water purification, blood purification, and catalyst carrier.

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