Water-resistant honeycomb activated carbon and preparation method thereof

Abstract

The present invention relates to a kind of water-resistant honeycomb activated carbon and preparation method thereof, belong to the technical field of activated carbon. A kind of preparation method of water-resistant honeycomb activated carbon comprises the following steps: 1) after heating and firing the coconut shell raw material after cleaning; 2) under nitrogen atmosphere, cyano-modified polyphenylene sulfide, polyetherimide, accelerator and activated carbon powder are mixed uniformly and then heated to react, cooled and washed, and dried; 3) N, N-dimethylacetamide is added to activated carbon intermediate and heated and extracted, solid is filtered and taken, put into anhydrous ethanol and soaked, solid is filtered and taken, after washing; 4) modified activated carbon is placed in anhydrous ethanol, tetrabutyl titanate is added and stirred and mixed, ferric nitrate solution is added by spraying under stirring, ultrasonic treatment is carried out after the addition of materials is completed, solid is filtered and taken, and microwave drying is carried out after centrifugation. The water-resistant honeycomb activated carbon prepared by the present invention has higher stability, water resistance and adsorption.

Description

Technical Field

[0001] The invention belongs to the technical field of activated carbon and relates to water-resistant honeycomb activated carbon and a preparation method thereof. Background Art

[0002] Honeycomb activated carbon features high specific surface area, acid and alkali resistance, a controllable pore structure, and reproducibility. It also boasts a high honeycomb structure with a high porosity, large geometric surface area, and strong resistance to wear and dust pollution. Compared to other types of activated carbon, honeycomb activated carbon's greatest advantage is its low pressure loss. These advantages make it suitable for gas purification, solvent recovery, and as a catalyst or catalyst carrier.

[0003] Unmodified activated carbon suffers from weak strength, susceptibility to wear, and poor water resistance. Commonly used activated carbon modification methods include surface oxidation, surface reduction, metal loading, and microwave modification. While numerous studies have explored ways to increase the adsorption capacity of activated carbon, limited research has been conducted on its long-term use in water. Prolonged immersion in water can cause the activated carbon structure to collapse, leading to a decrease in activity. Summary of the Invention

[0004] The purpose of the present invention is to provide a water-resistant honeycomb activated carbon and a preparation method thereof. By modifying polyphenylene sulfide and introducing a cyano group, the adsorption capacity of the modified activated carbon for metal ions can be effectively improved, and the distribution of titanium dioxide and iron oxides in the modified activated carbon can be promoted; in addition, by introducing polyphenylene sulfide into the activated carbon, its stability and water resistance can be effectively improved.

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

[0006] A method for preparing water-resistant honeycomb activated carbon, comprising the following steps:

[0007] 1) heating and firing the cleaned coconut shell raw material to obtain activated carbon powder;

[0008] 2) under a nitrogen atmosphere, uniformly mixing cyano-modified polyphenylene sulfide, polyetherimide, a promoter, and activated carbon powder, heating the mixture for reaction, cooling the mixture, washing the mixture, and drying the mixture to obtain an activated carbon intermediate;

[0009] 3) adding N,N-dimethylacetamide to the activated carbon intermediate and heating for extraction, filtering out the solid, soaking it in anhydrous ethanol, filtering out the solid, and washing it to obtain the modified activated carbon;

[0010] 4) The modified activated carbon is placed in anhydrous ethanol, tetrabutyl titanate is added and stirred, and then the ferric nitrate solution is sprayed into the mixture under stirring. After the addition is completed, ultrasonic treatment is performed, and the solid is filtered, centrifuged, and then microwave-dried to obtain a water-resistant honeycomb activated carbon.

[0011] As a preferred technical solution of the present invention, in step 1), the heating and firing conditions are heating to 110-120°C at 6-10°C / min, keeping warm for 30-45 minutes, heating to 900-950°C at 3-6°C / min, and firing for 200-300 minutes.

[0012] As a preferred technical solution of the present invention, in step 2), the heating reaction conditions are heating at 130-140°C for 30-45 minutes and then heating to 480-600°C for reaction for 3-4 hours; in step 2), the organic gas generated by the decomposition of polyetherimide at high temperature can expand the pore structure of the activated carbon, increase the porosity and specific surface area of ​​the activated carbon; and citric acid as an acidic catalyst can accelerate the reaction rate, promote the formation of activated carbon, and increase its active sites and pore structure.

[0013] As a preferred technical solution of the present invention, in step 3), the heating extraction condition is extraction at 60° C. for 6-8 hours; and the soaking time is 30-45 minutes.

[0014] As a preferred technical solution of the present invention, in step 4), the ultrasonic treatment conditions are as follows: an ultrasonic frequency of 20-50 Hz and a treatment time of 30-45 min; the microwave drying treatment time is 5-15 min; the concentration of the ferric nitrate solution is 0.3-0.5 mol / L; in step 4), during the hydrolysis of tetrabutyl titanate, since the modified activated carbon contains cyano groups,.

[0015] As a preferred technical solution of the present invention, in the preparation process of water-resistant honeycomb activated carbon, the mass ratio of the coconut shell raw material, cyano-modified polyphenylene sulfide, polyetherimide, accelerator, tetrabutyl titanate, and ferric nitrate solution is 70-90:10-20:4-10:0.2-0.4:5-8:10-16.

[0016] As a preferred technical solution of the present invention, the preparation method of the cyano-modified polyphenylene sulfide comprises the following steps: adding DDQ and polyphenylene sulfide to a reactor under a nitrogen atmosphere, stirring and mixing, then grinding, heating to 180-250° C., and keeping warm for 1.5-3.0 hours to obtain cyano-modified polyphenylene sulfide; in the solution of the present invention, the oxygen double bond of DDQ is opened and an ether bond is formed, and the hydrogen position on the long-chain benzene ring of polyphenylene sulfide is replaced by the ether bond, thereby achieving the modification of the polyphenylene sulfide.

[0017] The invention discloses a water-resistant honeycomb activated carbon prepared by adopting the preparation method.

[0018] As a preferred technical solution of the present invention, DDQ is dichlorodicyanobenzoquinone.

[0019] Beneficial effects of the present invention:

[0020] 1. The present invention modifies polyphenylene sulfide and introduces a cyano group, which can effectively improve the adsorption capacity of the modified activated carbon for metal ions and promote the distribution of titanium dioxide and iron oxides in the modified activated carbon. In addition, by introducing polyphenylene sulfide into the activated carbon, its stability and water resistance can be effectively improved.

[0021] 2. The present invention adds ferric nitrate solution by spraying, which can effectively control the hydrolysis rate of tetrabutyl titanate, make the water molecules in the ferric nitrate solution more evenly dispersed in the reaction system, slow down the occurrence of hydrolysis reaction, and maintain a high titanium dioxide yield. Ultrasonic treatment promotes the distribution of titanium dioxide and iron ions in the modified activated carbon; the present invention uses a microwave oven to perform a drying treatment to quickly remove moisture, further uniformize the distribution of titanium dioxide and iron oxides in the modified activated carbon, and significantly increase the loading amount of titanium dioxide and iron oxides, improve the loading uniformity, so that the final product has the characteristics of fine grains and high specific surface area. DETAILED DESCRIPTION

[0022] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the specific implementation methods, structures, features and effects of the present invention are described in detail below in combination with the embodiments.

[0023] Example 1

[0024] The preparation method of the cyano-modified polyphenylene sulfide comprises the following steps:

[0025] Under a nitrogen atmosphere, DDQ and polyphenylene sulfide were added to a reactor, stirred and mixed, and then ground. The mixture was heated to 180° C. and kept warm for 1.5 h to obtain cyano-modified polyphenylene sulfide.

[0026] A method for preparing water-resistant honeycomb activated carbon, comprising the following steps:

[0027] 1) heating and firing the cleaned coconut shell raw material to obtain activated carbon powder; wherein the heating and firing conditions are heating to 110° C. at 6° C. / min, keeping warm for 30 minutes, heating to 900° C. at 3° C. / min, and firing for 200 minutes;

[0028] 2) Under a nitrogen atmosphere, uniformly mixing cyano-modified polyphenylene sulfide, polyetherimide, citric acid solution, and activated carbon powder, heating the mixture for reaction, cooling the mixture, washing the mixture, and drying the mixture to obtain an activated carbon intermediate; wherein the heating reaction conditions are heating at 130° C. for 30 minutes, then heating the mixture to 480° C. for reaction for 3 hours; and the mass concentration of the citric acid solution is 14%;

[0029] 3) adding N,N-dimethylacetamide to the activated carbon intermediate for heating and extraction, filtering out the solid, soaking it in anhydrous ethanol, filtering out the solid, and washing it to obtain the modified activated carbon; wherein the heating extraction condition is extraction at 60° C. for 6 hours; and the soaking time is 30 minutes.

[0030] 4) placing the modified activated carbon in anhydrous ethanol, adding tetrabutyl titanate and stirring, spraying the ferric nitrate solution while stirring, performing ultrasonic treatment after the addition is completed, filtering the solid, centrifuging and then microwave drying to obtain water-resistant honeycomb activated carbon; wherein the ultrasonic treatment conditions are an ultrasonic frequency of 20 Hz and a treatment time of 30 min; the microwave drying treatment time is 5 min; and the concentration of the ferric nitrate solution is 0.3 mol / L.

[0031] In the preparation process of water-resistant honeycomb activated carbon, the mass ratio of the coconut shell raw material, cyano-modified polyphenylene sulfide, polyetherimide, citric acid solution, tetrabutyl titanate, and ferric nitrate solution is 70:10:4:0.2:5:10.

[0032] Example 2

[0033] The preparation method of the cyano-modified polyphenylene sulfide comprises the following steps:

[0034] Under a nitrogen atmosphere, DDQ and polyphenylene sulfide were added to a reactor, stirred and mixed, and then ground. The mixture was heated to 203° C. and kept warm for 2 h to obtain cyano-modified polyphenylene sulfide.

[0035] A method for preparing water-resistant honeycomb activated carbon, comprising the following steps:

[0036] 1) heating and firing the cleaned coconut shell raw material to obtain activated carbon powder; wherein the heating and firing conditions are heating to 113° C. at 7° C. / min, holding for 35 minutes, heating to 917° C. at 4° C. / min, and firing for 233 minutes;

[0037] 2) Under a nitrogen atmosphere, uniformly mixing cyano-modified polyphenylene sulfide, polyetherimide, citric acid solution, and activated carbon powder, heating the mixture for reaction, cooling, washing, and drying to obtain an activated carbon intermediate; wherein the heating reaction conditions are heating at 133° C. for 35 minutes, then heating to 520° C. for reaction for 3.3 hours; and the mass concentration of the citric acid solution is 16%;

[0038] 3) adding N,N-dimethylacetamide to the activated carbon intermediate for heating and extraction, filtering out the solid, soaking it in anhydrous ethanol, filtering out the solid, and washing it to obtain the modified activated carbon; wherein the heating extraction condition is extraction at 60° C. for 6.7 hours; and the soaking time is 35 minutes.

[0039] 4) placing the modified activated carbon in anhydrous ethanol, adding tetrabutyl titanate and stirring, spraying the ferric nitrate solution while stirring, performing ultrasonic treatment after the addition is completed, filtering the solid, centrifuging and then microwave drying to obtain water-resistant honeycomb activated carbon; wherein the ultrasonic treatment conditions are an ultrasonic frequency of 30 Hz and a treatment time of 35 min; the microwave drying treatment time is 8 min; and the concentration of the ferric nitrate solution is 0.37 mol / L.

[0040] In the preparation process of water-resistant honeycomb activated carbon, the mass ratio of the coconut shell raw material, cyano-modified polyphenylene sulfide, polyetherimide, citric acid solution, tetrabutyl titanate, and ferric nitrate solution is 77:13:6:0.27:6:12.

[0041] Example 3

[0042] The preparation method of the cyano-modified polyphenylene sulfide comprises the following steps:

[0043] Under a nitrogen atmosphere, DDQ and polyphenylene sulfide were added to a reactor, stirred and mixed, and then ground. The mixture was heated to 227° C. and kept warm for 2.5 h to obtain cyano-modified polyphenylene sulfide.

[0044] A method for preparing water-resistant honeycomb activated carbon, comprising the following steps:

[0045] 1) heating and firing the cleaned coconut shell raw material to obtain activated carbon powder; wherein the heating and firing conditions are heating to 117° C. at 9° C. / min, holding for 40 minutes, heating to 933° C. at 5° C. / min, and firing for 267 minutes;

[0046] 2) Under a nitrogen atmosphere, uniformly mixing cyano-modified polyphenylene sulfide, polyetherimide, citric acid solution, and activated carbon powder, heating the mixture for reaction, cooling, washing, and drying to obtain an activated carbon intermediate; wherein the heating reaction conditions are heating at 137° C. for 40 minutes, then heating to 560° C. for reaction for 3.7 hours; and the mass concentration of the citric acid solution is 18%;

[0047] 3) adding N,N-dimethylacetamide to the activated carbon intermediate for heating and extraction, filtering out the solid, soaking it in anhydrous ethanol, filtering out the solid, and washing it to obtain the modified activated carbon; wherein the heating extraction condition is extraction at 60° C. for 7.3 hours; and the soaking time is 40 minutes.

[0048] 4) placing the modified activated carbon in anhydrous ethanol, adding tetrabutyl titanate and stirring, spraying the ferric nitrate solution while stirring, performing ultrasonic treatment after the addition is completed, filtering the solid, centrifuging and then microwave drying to obtain water-resistant honeycomb activated carbon; wherein the ultrasonic treatment conditions are an ultrasonic frequency of 40 Hz and a treatment time of 40 min; the microwave drying treatment time is 12 min; and the concentration of the ferric nitrate solution is 0.43 mol / L.

[0049] In the preparation process of water-resistant honeycomb activated carbon, the mass ratio of the coconut shell raw material, cyano-modified polyphenylene sulfide, polyetherimide, citric acid solution, tetrabutyl titanate, and ferric nitrate solution is 83:17:8:0.33:7:14.

[0050] Example 4

[0051] The preparation method of the cyano-modified polyphenylene sulfide comprises the following steps:

[0052] Under a nitrogen atmosphere, DDQ and polyphenylene sulfide were added to a reactor, stirred and mixed, and then ground. The mixture was heated to 250° C. and kept warm for 3.0 h to obtain cyano-modified polyphenylene sulfide.

[0053] A method for preparing water-resistant honeycomb activated carbon, comprising the following steps:

[0054] 1) heating and firing the cleaned coconut shell raw material to obtain activated carbon powder; wherein the heating and firing conditions are heating to 120° C. at 10° C. / min, holding for 45 minutes, heating to 950° C. at 6° C. / min, and firing for 300 minutes;

[0055] 2) Under a nitrogen atmosphere, uniformly mixing cyano-modified polyphenylene sulfide, polyetherimide, citric acid solution, and activated carbon powder, heating the mixture, cooling the mixture, washing the mixture, and drying the mixture to obtain an activated carbon intermediate; wherein the heating reaction conditions are heating at 140° C. for 45 minutes, then heating the mixture to 600° C. for 4 hours; and the mass concentration of the citric acid solution is 20%;

[0056] 3) adding N,N-dimethylacetamide to the activated carbon intermediate for heating and extraction, filtering out the solid, soaking it in anhydrous ethanol, filtering out the solid, and washing it to obtain the modified activated carbon; wherein the heating extraction condition is extraction at 60° C. for 8 hours; and the soaking time is 45 minutes.

[0057] 4) placing the modified activated carbon in anhydrous ethanol, adding tetrabutyl titanate and stirring, spraying the ferric nitrate solution while stirring, performing ultrasonic treatment after the addition is completed, filtering the solid, centrifuging and then microwave drying to obtain water-resistant honeycomb activated carbon; wherein the ultrasonic treatment conditions are an ultrasonic frequency of 50 Hz and a treatment time of 45 min; the microwave drying treatment time is 15 min; and the concentration of the ferric nitrate solution is 0.5 mol / L.

[0058] In the preparation process of water-resistant honeycomb activated carbon, the mass ratio of the coconut shell raw material, cyano-modified polyphenylene sulfide, polyetherimide, citric acid solution, tetrabutyl titanate, and ferric nitrate solution is 90:20:10:0.4:8:16.

[0059] Comparative Example 1

[0060] Compared with Example 3, the difference is that comparative example 1 uses polyphenylene sulfide instead of cyano-modified polyphenylene sulfide, and the other components, preparation steps and parameters are the same.

[0061] Comparative Example 2

[0062] Compared with Example 3, the difference is that Comparative Example 2 does not use polyetherimide, and the other components, preparation steps and parameters are the same.

[0063] Comparative Example 3

[0064] Compared with Example 3, the difference is that Comparative Example 3 does not use cyano-modified polyphenylene sulfide, and the other components, preparation steps and parameters are the same.

[0065] Comparative Example 4

[0066] Compared with Example 3, the difference is that Comparative Example 4 does not use citric acid solution, and the other components, preparation steps and parameters are the same.

[0067] Comparative Example 5

[0068] Compared with Example 3, the difference is that tetrabutyl titanate is not used in Comparative Example 5, and the other components, preparation steps and parameters are the same.

[0069] Comparative Example 6

[0070] Compared with Example 3, the difference is that comparative example 6 uses titanium dioxide instead of tetrabutyl titanate, and the other components, preparation steps and parameters are the same.

[0071] Comparative Example 7

[0072] Compared with Example 3, the difference is that Comparative Example 7 does not use ferric nitrate solution, and the other components, preparation steps and parameters are the same.

[0073] Comparative Example 8

[0074] Compared with Example 3, the difference is that in Comparative Example 8, oven drying is substituted for microwave drying, and the other components, preparation steps and parameters are the same.

[0075] Water resistance test:

[0076] The water-resistant honeycomb activated carbons prepared in Examples 1-4 and Comparative Examples 1-4 were respectively immersed in water for 60 days, and then subjected to strength tests according to GB / T 20451-2006 Activated Carbon Ball-on-Disc Strength Test Method. The test results are shown in Table 1.

[0077] Table 1 (Unit: MPa)

[0078]

[0079]

[0080] Static adsorption test:

[0081] The water-resistant honeycomb activated carbons prepared in Examples 1-4 and Comparative Examples 1-8 were subjected to static adsorption experiments on methanol, benzene, and n-hexane, respectively. The static adsorption results are shown in Table 2.

[0082] Table 2 (unit: mg / g)

[0083] Methanol adsorption capacity Benzene adsorption capacity n-Hexane adsorption capacity Example 1 12.8 13.5 14.9 Example 2 14.4 16.5 18.4 Example 3 18.3 20.8 23.4 Example 4 17.2 19.1 21.8 Comparative Example 1 8.0 7.7 8.7 Comparative Example 2 7.1 6.6 7.4 Comparative Example 3 5.1 4.9 5.9 Comparative Example 4 10.3 13.6 15.6 Comparative Example 5 10.3 12.9 15.3 Comparative Example 6 12.3 10.9 12.9 Comparative Example 7 8.3 12 13.9 Comparative Example 8 16.8 19.5 22.1

[0084] From the test results in Table 1 and Table 2, it can be seen that compared with Comparative Examples 1-8, the water-resistant honeycomb activated carbons prepared in Examples 1-4 of the present invention have significant water resistance and adsorption effects.

[0085] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as above in terms of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can, without departing from the scope of the technical solution of the present invention, make some changes or modifications to equivalent embodiments using the technical contents disclosed above. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A method for preparing water-resistant honeycomb activated carbon, characterized in that: The preparation method comprises the following steps: 1) heating and firing the cleaned coconut shell raw material to obtain activated carbon powder; 2) under a nitrogen atmosphere, uniformly mixing cyano-modified polyphenylene sulfide, polyetherimide, a promoter, and activated carbon powder, heating the mixture for reaction, cooling the mixture, washing the mixture, and drying the mixture to obtain an activated carbon intermediate; 3) adding N,N-dimethylacetamide to the activated carbon intermediate and heating for extraction, filtering out the solid, soaking it in anhydrous ethanol, filtering out the solid, and washing it to obtain the modified activated carbon; 4) placing the modified activated carbon in anhydrous ethanol, adding tetrabutyl titanate and stirring, spraying the ferric nitrate solution while stirring, performing ultrasonic treatment after the addition is completed, filtering the solid, centrifuging and then microwave drying to obtain a water-resistant honeycomb activated carbon; The accelerator is a citric acid solution with a mass concentration of 14-20%; The preparation method of the cyano-modified polyphenylene sulfide comprises the following steps: adding dichlorodicyanobenzoquinone and polyphenylene sulfide into a reaction kettle under a nitrogen atmosphere, stirring and mixing, grinding, heating to 180-250° C., and keeping the temperature for 1.5-3.0 hours to obtain the cyano-modified polyphenylene sulfide.

2. The method for preparing water-resistant honeycomb activated carbon according to claim 1, wherein: In step 1), the heating and firing conditions are: heating to 110-120°C at 6-10°C / min, keeping warm for 30-45 minutes, heating to 900-950°C at 3-6°C / min, and firing for 200-300 minutes.

3. The method for preparing water-resistant honeycomb activated carbon according to claim 1, wherein: In step 2), the heating reaction conditions are heating at 130-140° C. for 30-45 minutes, then heating to 480-600° C. for reaction for 3-4 hours.

4. The method for preparing water-resistant honeycomb activated carbon according to claim 1, wherein: In step 3), the heating extraction condition is extraction at 60° C. for 6-8 hours; and the soaking time is 30-45 minutes.

5. The method for preparing water-resistant honeycomb activated carbon according to claim 1, wherein: In step 4), the ultrasonic treatment conditions are as follows: an ultrasonic frequency of 20-50 Hz, a treatment time of 30-45 min; the microwave drying treatment time is 5-15 min; and the concentration of the ferric nitrate solution is 0.3-0.5 mol / L.

6. The method for preparing water-resistant honeycomb activated carbon according to claim 1, wherein: In the preparation process of water-resistant honeycomb activated carbon, the mass ratio of the coconut shell raw material, cyano-modified polyphenylene sulfide, polyetherimide, accelerator, tetrabutyl titanate, and ferric nitrate solution is 70-90:10-20:4-10:0.2-0.4:5-8:10-16.

7. A water-resistant honeycomb activated carbon prepared by the preparation method according to any one of claims 1 to 6.

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