WO2023103997A1

WO2023103997A1 - Fluorine-free, waterproof and moisture-proof superhydrophobic activated carbon, and preparation method therefor and use thereof

Info

Publication number: WO2023103997A1
Application number: PCT/CN2022/136733
Authority: WO
Inventors: 张友法; 焦玄; 苏有荣
Original assignee: 东南大学; 南京济德环境科技有限公司
Priority date: 2021-12-06
Filing date: 2022-12-06
Publication date: 2023-06-15
Also published as: CN114408924B; CN114408924A

Abstract

A fluorine-free, waterproof and moisture-proof superhydrophobic activated carbon, and a preparation method therefor and the use thereof, which belong to the technical field of bionic nano-coatings. The method comprises: after activated carbon particles are dried, firstly, soaking same in a mixed pretreatment solution containing polydimethylsiloxane and a hydrophobic silicon dioxide nano-powder, taking out and airing same until there are no obvious liquid drops on the surface, then, placing same in an aqueous superhydrophobic modification solution, loading modified nanoparticles on the activated carbon by means of rotary evaporation, and finally, curing same at a high temperature to obtain a fluorine-free, superhydrophobic and moisture-proof activated carbon. The prepared product can be used in multiple fields such as VOC removal, water purification, industrial wastewater treatment, and factory tail gas catalysis, has a good resistance effect on water vapor, and can maintain good moisture-proof and selective adsorption characteristics under high-humidity conditions. The method has characteristics such as a low cost, a simple process flow, low equipment requirements, and a flexible and changeable design scheme, and is beneficial for industrial large-scale production.

Description

A kind of fluorine-free waterproof and moisture-proof superhydrophobic activated carbon and its preparation method and application

technical field

The invention belongs to the technical field of bionic nano-coating, and relates to a fluorine-free superhydrophobic moisture-proof activated carbon and a preparation method thereof.

Background technique

Activated carbon is prepared from carbon-containing raw materials such as wood, coal, and fruit shells, which are pyrolyzed under air-isolated conditions and activated by reducing gas. During this process, new micropores will be generated and original pores will be enlarged to improve Microporous structure increases activity. The micropore diameter of activated carbon is mostly between 2-50nm, and has a huge specific surface area. It is this unique internal structure that makes activated carbon have excellent adsorption capacity. Activated carbon is widely used, including air purification, tap water treatment , Purification of drinking water, conditioning of soil properties, removal of indoor organic gases, etc. According to reports, the world's annual production of activated carbon is gradually increasing, indicating that the demand for activated carbon applications is also increasing.

As an adsorbent material with excellent performance, activated carbon not only has a specific crystal structure and pore structure inside, but also has different functional group structures on its surface, such as carbonyl, carboxyl, phenols, lactones, quinones, ethers. Some of the oxides and complexes contained on these surfaces come from derivatives of raw materials, and some are generated by the action of air or water vapor during or after activation. Due to the existence of a large number of oxygen-containing functional groups, the surface of activated carbon is in a hydrophilic state. In high humidity or aqueous solution environment, water molecules will be adsorbed in the internal pores of activated carbon, which seriously reduces the adsorption effect on other organic substances, weakens the service life, and increases Cost of production. Therefore, it is particularly important to improve the hydrophobicity of activated carbon and enhance the resistance to water vapor in its practical applications.

At present, there are roughly two types of methods commonly used to improve the hydrophobic properties of activated carbon. One is to remove the hydrophilic groups on the surface through high-temperature calcination, microwave treatment or gas phase reduction. Although the hydrophobicity has been improved to a certain extent, it cannot cope with the adsorption of high humidity. conditions, the moisture-proof effect is very limited. The second is to soak it in low surface materials or resin materials to improve the waterproof effect, but resin materials will block the pore structure of activated carbon and reduce the adsorption capacity, and most of the low surface energy materials used are fluorine-containing long-chain polymers. It is not conducive to the adsorption of organic matter and will cause serious environmental pollution.

In addition, compared with the two previously disclosed inventions, this invention also has many optimizations and improvements. In the CN 107321304 A invention, for the modification of activated carbon particles, superhydrophobic activated carbon can be obtained by chemical vapor deposition or directly soaking it in a solution of low surface energy substances, followed by drying and curing at high temperature. In the CN109647342A invention, the modified nanoparticles are directly loaded on the surface of activated carbon, and the moisture-proof super-hydrophobic activated carbon is obtained after curing. The modified low surface energy materials in the previous work are mainly fluorine-containing high polymers, which are not conducive to the adsorption of organic matter, and the load without particles on the surface is directly modified with low surface energy materials, and its moisture-proof effect is limited, so it cannot be applied in high-temperature applications. Service environment under humidity or aqueous solution conditions. This invention is treated with a primer before loading particles, which is more conducive to the attachment of nanoparticles after pre-roughening, and at the same time enhances the cohesive force. Compared with directly loading nanoparticles, the mechanical stability of the modified activated carbon surface is greatly improved. sex. In addition, compared with the previous invention, another obvious advantage of this invention is that it uses deionized water as a solvent to reduce pollution to water bodies and the atmospheric environment, while reducing production costs.

Contents of the invention

Technical problem to be solved: Aiming at the main technical problem of poor moisture-proof effect of existing activated carbon, the present invention provides a fluorine-free superhydrophobic moisture-proof activated carbon and its preparation method and application. The invention has the advantages of low cost, simple process flow, low equipment requirements, and design The scheme is flexible and changeable, suitable for large-scale industrial preparation. Superhydrophobic activated carbon can be applied to various air filtration and water treatment occasions, so that activated carbon can resist the entry of water molecules in high humidity and aqueous solution environments, and take into account good adsorption characteristics and stability. It expands the application of activated carbon in real life.

Technical solution: a method for preparing fluorine-free waterproof and moisture-proof super-hydrophobic activated carbon, the preparation steps are: raw materials: select activated carbon as one of coal, wood, and shell activated carbon, and the moisture content is not higher than 2wt.%; pretreatment: First, add 1-2 parts of polydimethylsiloxane (PDMS) to 40-50 parts of ethyl acetate or deionized water containing surfactants, stir at room temperature and then add 0.1-1 parts of hydrophobic silica nanopowder and 0.1 -0.2 parts of PDMS curing agent, keep stirring to obtain a pretreatment solution; soak the activated carbon in the pretreatment solution, take it out and dry it after 5-10min; the mass content of the surfactant in deionized water is 0.2-0.5%; The hydrophobic silica nanopowder is obtained by drying silica sol or fumed silica grafted with a hydrophobic group with a particle diameter of 4-10nm, and the hydrophobic group is methyl, propyl, isobutyl or octyl; modified : Disperse 0.1-0.5 parts of surfactant, 2-4 parts of ammonia water, and 1-2 parts of hydrophilic silica in 80-100 parts of deionized water, stir at 50°C for 30 minutes, then add 0.2-0.5 parts of modified Stir continuously for 16-24 hours to obtain a modified solution; or directly disperse 1-2 parts of hydrophilic silica nanopowder and 1-5 parts of water-based alkylsiloxane oligomer in 80-100 parts of deionized water , Stir continuously at 50°C for 4-6h to obtain a modified solution; soak the pretreated activated carbon into the modified solution, the mass ratio of activated carbon to modified solution is 1: (1.5-3), after 5-10min, at 50 Vacuum rotation at -80°C for 45-60 minutes to obtain modified activated carbon; the hydrophilic silica is obtained by grafting KH550 silane coupling agent groups on silica sol with a particle diameter of 4-10 nm and drying; the modifier is Fluorine-free alkyl siloxane with a carbon chain length greater than 3, the content in the modified solution is 1wt.%-10wt.%; the water-based alkylsiloxane oligomer is water-based isobutylsiloxane, Water-based octyl siloxane or water-based propyl siloxane; Curing: Take out the modified activated carbon and put it in an oven at 200-250°C for 30min-4h to obtain fluorine-free waterproof and moisture-proof superhydrophobic activated carbon.

Preferably, the above-mentioned fluorine-free alkyl siloxane is isobutyl siloxane, octyl siloxane or propyl siloxane.

Preferably, the above-mentioned modifying agent is a fluorine-free alkyl siloxane stock solution, or a fluorine-free alkyl siloxane diluent whose solvent is n-hexane.

The above surfactants are polyether modified silicone leveling agents, cationic fluorocarbon surfactants or nonionic fluorocarbon surfactants.

The fluorine-free waterproof and moisture-proof superhydrophobic activated carbon prepared by the above preparation method.

The above-mentioned fluorine-free waterproof and moisture-proof super-hydrophobic activated carbon, in the environment with a relative humidity of 60-99% or in water for 24 hours, the moisture absorption or water absorption weight gain is less than 10%, and in the environment with a relative humidity of 60-99% or in water for 90 day, moisture absorption or water absorption weight gain is less than 20%; compared with untreated activated carbon, superhydrophobic activated carbon can still efficiently adsorb organic matter in moisture or water, and the adsorption efficiency is increased by more than 95%. The adsorbate can be desorbed.

Application of the above-mentioned fluorine-free waterproof and moisture-proof superhydrophobic activated carbon in the preparation of COD and VOC removal products.

Beneficial effects: (1) The method of the present invention is low in cost, simple in process flow, low in equipment requirements, flexible in design, and suitable for large-scale industrial production. (2) The method of the present invention adopts the mixed solution of PDMS and hydrophobic silica nanopowder to carry out pretreatment, can realize the pre-roughening treatment on the surface of activated carbon particles, increase the attachment site of modified nanoparticles, which is stronger The cohesiveness of the nanoparticles can make the nanoparticle loading more compact and improve the mechanical stability. At the same time, PDMS also has a good hydrophobic effect, and its main component is polydimethylsiloxane, so the pretreatment solution and the modified solution will undergo chemical cross-linking on the surface of activated carbon, which has synergistic effect and further improves the moisture-proof effect of activated carbon. . (3) Both the pretreatment solution and the superhydrophobic modification solution in the method of the present invention can use deionized water as a solvent, reduce the use of organic solvents, improve production safety, and reduce use costs, while greatly reducing pollution to the environment. (4) The method of the present invention loads and accumulates nanoparticles on the surface of activated carbon particles to construct a typical micro-nano composite structure, which is the structural basis for the surface to achieve super-hydrophobic effect. And the stacking of nanoparticles will also generate a new pore structure. Therefore, on the premise of ensuring excellent super-hydrophobic effect, the entire modification process has little effect on the microporous structure, pore characteristics and specific surface area inside the activated carbon, which reduces the adsorption of activated carbon. Interference with performance. (5) The product prepared by the method of the present invention is fluorine-free super-hydrophobic activated carbon, through the synergistic effect of the surface multi-level structure and groups such as methyl and methylene, the modified activated carbon has super-hydrophobic properties, and can be used under high humidity conditions. It has a good moisture-proof effect under the condition of relative humidity of 99%, the 24h weight gain is less than 10%, and it can self-decompose at room temperature. At the same time, the fluorine-free modification makes the product have a stronger affinity for different types of organic substances, so it has good selective adsorption characteristics for VOC and other substances in aqueous solution and high humidity environment. (6) The fluorine-free superhydrophobic activated carbon prepared by the method of the present invention exhibits high-efficiency adsorption performance and service life in many high-humidity scenes, reduces the use of materials, reduces production costs, and can be used to control environmental pollution such as air and water bodies , and also avoid the generation of a large number of organic pollutants in the preparation process, which has important application prospects.

Description of drawings

Fig. 1 is the microscopic characterization and hydrophobic characteristic of fluorine-free superhydrophobic activated carbon and unmodified activated carbon described in embodiment 1;

Fig. 2 is the condensation characteristic of fluorine-free superhydrophobic activated carbon and unmodified activated carbon described in embodiment 2;

Fig. 3 is the drop impact test of fluorine-free superhydrophobic activated carbon and unmodified activated carbon described in embodiment 3;

Fig. 4 is the specific surface area and pore characteristics of fluorine-free superhydrophobic activated carbon and unmodified activated carbon described in embodiment 4;

Fig. 5 is the long-term waterproof and moisture-proof characteristic of fluorine-free superhydrophobic activated carbon described in embodiment 5;

Fig. 6 is the fluorine-free superhydrophobic activated carbon described in embodiment 6 to the adsorption amount of different organic matter, and the variation of the adsorption amount after absorbing moisture and soaking in water;

Fig. 7 is the absorption efficiency and regeneration performance of microemulsion to the fluorine-free superhydrophobic activated carbon described in embodiment 7;

Figure 8 is the selective adsorption of fluorine-free superhydrophobic activated carbon to organic gases under high humidity conditions described in Example 8;

Fig. 9 is the 24h moisture absorption weight gain under the condition of RH=99% of different formula fluorine-free superhydrophobic activated carbon described in embodiment 9;

Fig. 10 is 24h moisture absorption comparison and contact angle and macroscopic photo of fluorine-free superhydrophobic activated carbon powder described in embodiment 10;

Fig. 11 is the desorption test of fluorine-free superhydrophobic activated carbon and unmodified activated carbon described in embodiment 11 after moisture absorption/soaking in water;

Fig. 12 is the adsorption-desorption cycle test of fluorine-free superhydrophobic activated carbon and unmodified activated carbon described in embodiment 12;

Figure 13 is the real-time change result of the CTC value of fluorine-free superhydrophobic activated carbon and unmodified activated carbon described in Example 13 after moisture absorption/water soaking;

Figure 14 is the adsorption oil mist test of fluorine-free superhydrophobic activated carbon and unmodified activated carbon described in Example 14 under the condition of RH=99%;

Fig. 15 is that fluorine-free superhydrophobic activated carbon described in embodiment 15 and unmodified activated carbon are to edible oil microemulsion and DMF solution COD removal test;

Fig. 16 is 200mg/L edible oil microemulsion and DMF solution service life test of fluorine-free superhydrophobic activated carbon and unmodified activated carbon described in embodiment 16 to initial COD concentration;

Fig. 17 is the toluene and DMF steam removal test under the condition of RH=99% of fluorine-free superhydrophobic activated carbon and unmodified activated carbon described in embodiment 17;

Fig. 18 is the life test of 100mg/L toluene and DMF steam to the initial concentration under the condition of RH=99% for fluorine-free superhydrophobic activated carbon and unmodified activated carbon described in embodiment 18;

Figure 19 shows the CTC value change results of fluorine-free superhydrophobic activated carbon and unmodified activated carbon described in Example 19 after COD removal and VOC regeneration.

Specific embodiments

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

In a certain embodiment (Example 2), it is mentioned that the pretreatment solution can be replaced by hydrophobic fumed silica.

In a certain example (Example 3), it is mentioned that the modified solution can be directly added with silica sol, without making powder or modifying with KH550.

In a certain example (Example 7), it is mentioned that alkylsiloxane and surfactant can be added together in the modification solution, and the effect of water-based alkylsiloxane oligomer can also be achieved.

Example 1

Raw materials: Coal-based columnar activated carbon with a moisture content of 1.5% is selected. Pretreatment: First add 1 part of polydimethylsiloxane (PDMS) to 40 parts of ethyl acetate, stir at room temperature for 10 minutes, then add 0.1 part of hydrophobic silica nanopowder and 0.1 part of butyl acetate and isocyanate mixture (mass ratio 1:1) as a PDMS curing agent, the pretreatment solution can be obtained by continuous stirring for 30 minutes; the hydrophobic silica nanopowder described here is a commercial hydrophobic gas phase nano-silica Hydrophobic-100 type; according to the weight ratio of 1:6, the activated carbon Soak the particles in the pretreatment solution, take them out after 5 minutes and dry them until there is no obvious moisture on the surface; modification: disperse 0.1 parts of polyether modified silicone leveling agent, 2 parts of ammonia water, and 1 part of hydrophilic silica in 80 parts In deionized water, after stirring at 50°C for 30 minutes, add 0.3 parts of butyltrimethoxysiloxane dropwise, and continue stirring for 16 hours to obtain a modified solution; the hydrophilic silica described here is a silica sol with a particle diameter of 4-10 nm, It is obtained by adding 0.5wt.% KH550 aqueous solution, reacting for 6 hours under alkaline conditions and then drying. According to the weight ratio of 1:2, the pretreated activated carbon was soaked into the modified solution, and after 10 minutes, it was rotated in vacuum at 80°C for 50 minutes, so that the modified solution was evenly wrapped on the activated carbon to obtain modified activated carbon; solidification: the modified The activated carbon was taken out and placed in an oven at 220°C for 2 hours to obtain the superhydrophobic activated carbon.

After modification, the surface of activated carbon has a typical micro-nano composite structure, which can maintain excellent hydrophobicity. The surface of unmodified activated carbon is obviously hydrophilic, and the static water contact angle is 34.5°. The activated carbon has an obvious water film under the liquid, and the static contact angle is 152.3°.

Example 2

Raw materials: Wooden columnar activated carbon with a moisture content of 1.8% is selected. Primer coating: first add 1.5 parts of polydimethylsiloxane (PDMS) to 50 parts of ethyl acetate, stir at room temperature for 10 minutes, then add 0.6 parts of hydrophobic fumed silica nanopowder and 0.15 parts of butyl acetate and isocyanate mixture (Mass ratio 1:1) As a PDMS curing agent, the pretreatment solution can be obtained by continuous stirring for 30 minutes; the hydrophobic silica nanopowder described here is the commercial hydrophobic fumed nanosilica Hydrophobic-100 type. According to the weight ratio of 1:6, soak the activated carbon particles in the pretreatment solution, take it out after 10 minutes and dry it until there is no obvious moisture on the surface; modification: 0.3 parts of polyether modified silicone leveling agent, 2.5 parts of ammonia water, 1.6 parts Hydrophilic silica was dispersed in 92 parts of deionized water, after stirring at 50°C for 30 minutes, 0.2 parts of octyltrimethoxysiloxane was added dropwise, and stirring was continued for 24 hours to obtain a modified solution; the hydrophilic silica described here It is a silica sol with a particle diameter of 4-10 nm, which is obtained by adding 0.5 wt.% KH550 aqueous solution, reacting for 6 hours under alkaline conditions, and then drying. According to the weight ratio of 1:2.5, the pretreated activated carbon was soaked into the modified solution, and after 10 minutes, it was rotated in vacuum at 75°C for 55 minutes, so that g modified solution was evenly wrapped on the activated carbon to obtain modified activated carbon; solidification: The modified activated carbon was taken out and placed in an oven at 250°C for 30 minutes to solidify to obtain the superhydrophobic activated carbon.

The modified activated carbon has obvious drop-like condensation phenomenon, and the droplets are prone to bounce. However, the unmodified activated carbon has obvious film condensation, and the liquid droplets are easy to penetrate into the inside of the channel.

Example 3

Raw materials: Wooden columnar activated carbon with a moisture content of 1.5% is selected. Pretreatment: First, add 1.3 parts of polydimethylsiloxane (PDMS) to 47 parts of ethyl acetate, stir at room temperature for 10 minutes, then add 0.35 parts of hydrophobic silica nanopowder and 0.13 parts of mixed solution of butyl acetate and isocyanate (mass Ratio 1:1) as a PDMS curing agent, the pretreatment solution can be obtained by continuous stirring for 30 minutes; the hydrophobic silica nano-powder described here is the commercial hydrophobic fumed nano-silica Hydrophobic-100 type. According to the weight ratio of 1:6, soak the activated carbon particles in the pretreatment solution, take it out after 10 minutes and dry it until there is no obvious moisture on the surface; modification: 0.25 parts of cationic fluorocarbon surfactant, 2.4 parts of ammonia water, 1.3 parts of particle diameter 4-10nm hydrophilic fumed silica was dispersed in 87 parts of deionized water, stirred at 50°C for 30 minutes, then 0.3 parts of octyltrimethoxysilane was added dropwise, and stirred continuously for 20 hours to obtain a modified solution; the hydrophilic Silica is a silica sol with a particle diameter of 4-10nm, which is obtained by adding 0.5wt.% KH550 aqueous solution, reacting under alkaline conditions for 6 hours and then drying; according to the weight ratio of 1:2.4, the pretreated activated carbon is soaked in modified After 5 minutes, rotate in vacuum at 80°C for 55 minutes, so that the modified solution is evenly wrapped on the activated carbon to obtain modified activated carbon; curing: take out the modified activated carbon and place it in an oven at 230°C for 4 hours to obtain the described superhydrophobic activated carbon.

The surface of untreated activated carbon is in a hydrophilic state, and water droplets will adhere to the surface after impact. The surface of modified activated carbon is in a superhydrophobic state, and water droplets will easily bounce off after impact.

Example 4

Raw materials: Coal-based columnar activated carbon with a moisture content of 2.0% is selected. Pretreatment: First, add 1 part of polydimethylsiloxane (PDMS) to 45 parts of ethyl acetate, stir at room temperature for 10 minutes, then add 0.5 part of hydrophobic silica nanopowder and 0.1 part of mixed solution of butyl acetate and isocyanate (mass ratio 1:1) as a PDMS curing agent, the pretreatment solution can be obtained by continuous stirring for 30 minutes; the hydrophobic silica nanopowder described here is the commercial hydrophobic fumed nanosilica Hydrophobic-100 type. According to the weight ratio of 1:6, soak the activated carbon particles in the pretreatment solution, take it out after 10 minutes and dry it until there is no obvious moisture on the surface; modification: 0.2 parts of cationic fluorocarbon surfactant, 3 parts of ammonia water, 1.5 parts of particle pro- Aqueous silica was dispersed in 90 parts of deionized water, after stirring at 50°C for 30 minutes, 0.35 parts of isobutyltrimethoxysiloxane was added dropwise, and stirring was continued for 24 hours to obtain a modified solution; the hydrophilic silica mentioned here It is a silica sol with a particle diameter of 4-10nm, which is obtained by adding 0.5wt.% KH550 aqueous solution, reacting under alkaline conditions for 6 hours and then drying; according to the weight ratio of 1:1.5, soak the pretreated activated carbon into the modified solution, After 5 minutes, rotate in vacuum at 75°C for 55 minutes, so that the modified solution is evenly wrapped on the activated carbon to obtain a modified activated carbon; curing: take out the modified activated carbon and place it in an oven at 250°C for 2 hours to obtain the superhydrophobic activated carbon. .

The specific surface area of the untreated activated carbon is 812.18m ² /g, and that of the modified activated carbon is 841.69m ² /g, indicating that the modified surface attaches nanometers to increase the surface roughness and retain the internal pore structure.

Example 5

Raw materials: Wooden columnar activated carbon with a moisture content of 1.3% is selected. Pretreatment: First, add 1.5 parts of polydimethylsiloxane (PDMS) to 40 parts of deionized water containing non-ionic fluorocarbon surfactants, stir at room temperature for 10 minutes, then add 0.15 parts of hydrophobic silica nanopowder and 0.15 parts of The mixed solution of butyl acetate and isocyanate (mass ratio 1:1) is used as the PDMS curing agent, and the pretreatment solution can be obtained by continuous stirring for 30 minutes; the hydrophobic silica nano-powder described here is commercial hydrophobic fumed nano-silica Hydrophobic-100 ;According to the weight ratio of 1:6, soak the activated carbon particles in the pretreatment solution, take it out after 10 minutes and dry it until there is no obvious moisture on the surface; modification: directly mix 1.5 parts of hydrophilic silica nanopowder, 2 parts of water-based propyl silicon The oxane oligomer is dispersed in 80 parts of deionized water, and continuously stirred at 50°C for 6 hours to obtain a modified solution; the hydrophilic silica described here is a silica sol with a particle diameter of 4-10nm, and an aqueous solution of KH550 containing 0.5wt.% is added , obtained by drying under alkaline conditions for 6 hours; according to the weight ratio of 1:2.5, the pretreated activated carbon was soaked into the modified solution, and after 10 minutes, it was rotated under vacuum at 80°C for 55 minutes to make the modified solution evenly wrapped On the activated carbon, the modified activated carbon is obtained; curing: the modified activated carbon is taken out and placed in an oven at 250°C for 3 hours to obtain the superhydrophobic activated carbon.

The activated carbon is placed in a closed container with a relative humidity of 99% for a long time. The moisture absorption weight gain of the modified activated carbon is about 12%, and the moisture absorption weight gain of the unmodified activated carbon is about 47%. The moisture-proof effect is obvious and the performance is stable. And after soaking in water for a long time, the weight gain of the modified activated carbon is about 19%, and that of the unmodified activated carbon is more than 120%, and the waterproof effect is remarkable.

Example 6

Raw materials: use shell columnar activated carbon with a moisture content of 1.6%. Pretreatment: First, add 1.8 parts of polydimethylsiloxane (PDMS) to 50 parts of deionized water containing non-ionic fluorocarbon surfactants, stir at room temperature for 10 minutes, then add 0.8 parts of hydrophobic silica nanopowder and 0.18 parts of acetic acid The mixed solution of butyl ester and isocyanate (mass ratio 1:1) is used as PDMS curing agent, and the pretreatment solution can be obtained by continuous stirring for 30 minutes; the hydrophobic silica nano-powder described here is commercial hydrophobic fumed nano-silica Hydrophobic-100 type; According to the weight ratio of 1:6, soak the activated carbon particles in the pretreatment solution, take it out after 5 minutes and dry it until there is no obvious moisture on the surface; modification: 0.35 parts of non-ionic fluorocarbon surfactant, 3.5 parts of ammonia water, 1.8 parts of pro- Aqueous fumed silica is dispersed in 100 parts of deionized water, stirred at 50°C for 30 minutes, then 0.4 parts of propyltrimethoxysilane is added dropwise, and stirred continuously for 20 hours to obtain a modified solution; the hydrophilic silica mentioned here is particle Silica sol with a diameter of 4-10nm is added to the KH550 aqueous solution containing 0.5wt.%, and it is obtained by drying under alkaline conditions for 6 hours; according to the weight ratio of 1:2.8, soak the pretreated activated carbon into the modified solution, and after 5 minutes , rotate in vacuum at 75°C for 55 minutes, so that the modified solution is evenly wrapped on the activated carbon to obtain modified activated carbon; curing: take out the modified activated carbon and place it in an oven at 250°C for curing for 2 hours to obtain the superhydrophobic activated carbon.

The adsorption capacity of activated carbon for different organic substances before and after modification is similar, but after absorbing moisture or soaking in water for 2 hours, the adsorption effect of unmodified activated carbon on different organic substances decreases seriously, while the modified activated carbon almost maintains the original adsorption performance.

Example 7

Raw materials: Wooden columnar activated carbon with a moisture content of 1.4% is selected. Pretreatment: First, add 1.4 parts of polydimethylsiloxane (PDMS) to 50 parts of deionized water containing polyether modified silicone leveling agent, stir at room temperature for 10 minutes, then add 0.8 parts of hydrophobic silica nanopowder and 0.14 One part of butyl acetate and isocyanate mixed solution (mass ratio 1:1) is used as PDMS curing agent, and the pretreatment solution can be obtained by continuous stirring for 30 minutes; the hydrophobic silica nano powder described here is commercial hydrophobic fumed nano silica Hydrophobic-100 type; according to the weight ratio of 1:6, soak the activated carbon particles in the pretreatment solution, take it out after 5 minutes and dry it until there is no obvious moisture on the surface; modification: 1.6 parts of hydrophilic silica nanopowder, 0.5 parts of silicone leveling agent, 3.2 parts of isobutyl siloxane dispersed in 92 parts of deionized water, and continuously stirred at 50°C for 5 hours to obtain a modified solution; the hydrophilic silica mentioned here is a silica sol with a particle diameter of 4-10nm, and 0.5wt .% KH550 aqueous solution, obtained by drying under alkaline conditions for 6 hours; according to the weight ratio of 1:3, the pretreated activated carbon was soaked into the modified solution, and after 5 minutes, it was rotated under vacuum at 80°C for 45 minutes to make The modified solution is evenly wrapped on the activated carbon to obtain the modified activated carbon; curing: the modified activated carbon is taken out and placed in an oven at 200°C for 4 hours to obtain the superhydrophobic activated carbon.

The modified activated carbon has an excellent removal effect on the microemulsion, and it still maintains a high removal efficiency after 16 consecutive adsorptions, and the adsorption performance is restored after regeneration at 80 °C.

Example 8

Raw materials: use shell columnar activated carbon with a moisture content of 1.5%. Pretreatment: first add 2 parts of polydimethylsiloxane (PDMS) to 50 parts of deionized water containing polyether modified silicone leveling agent, stir at room temperature for 10 minutes, then add 0.5 parts of hydrophobic silica nanopowder and 0.2 One part of butyl acetate and isocyanate mixed solution (mass ratio 1:1) is used as PDMS curing agent, and the pretreatment solution can be obtained by continuous stirring for 30 minutes; the hydrophobic silica nano powder described here is commercial hydrophobic fumed nano silica Hydrophobic-100 type; according to the weight ratio of 1:6, soak the activated carbon particles in the pretreatment solution, take it out after 10 minutes and dry it until there is no obvious moisture on the surface; modification: directly mix 2 parts of hydrophilic silica nanopowder, 3 parts of water-based propyl The siloxane oligomer was dispersed in 100 parts of deionized water, and continuously stirred at 50°C for 6 hours to obtain a modified solution; the hydrophilic silica described here was a silica sol with a particle diameter of 4-10nm, and KH550 containing 0.5wt.% was added In the aqueous solution, it is obtained by drying under alkaline conditions for 6 hours; according to the weight ratio of 1:3, the pretreated activated carbon is soaked into the modified solution, and after 10 minutes, it is rotated under vacuum at 80°C for 60 minutes to make the modified solution uniform. Wrapped on activated carbon to obtain modified activated carbon; curing: the modified activated carbon was taken out and placed in an oven at 250°C for 2 hours to obtain the superhydrophobic activated carbon.

The adsorption capacity of the modified activated carbon to toluene at a relative humidity of 90% was similar to that under dry conditions, showing excellent selective adsorption, while the adsorption capacity of unmodified activated carbon decreased significantly at high humidity.

Example 9

Raw materials: use shell columnar activated carbon with a moisture content of 1.8%. Pretreatment: First, add 1.7 parts of polydimethylsiloxane (PDMS) to 46 parts of deionized water containing polyether modified silicone leveling agent, stir at room temperature for 10 minutes, then add 0.35 parts of hydrophobic silica nanopowder and 0.17 One part of butyl acetate and isocyanate mixed solution (mass ratio 1:1) is used as PDMS curing agent, and the pretreatment solution can be obtained by continuous stirring for 30 minutes; the hydrophobic silica nano powder described here is commercial hydrophobic fumed nano silica Hydrophobic-100 type; according to the weight ratio of 1:6, soak the activated carbon particles in the pretreatment solution, take it out after 10 minutes and dry it until there is no obvious moisture on the surface; modification: mix 0.23 parts of polyether modified silicone leveling agent, 2.6 parts of ammonia water, Disperse 1.6 parts of hydrophilic silica in 94 parts of deionized water, stir at 50°C for 30 minutes, add 0.3 parts of propyltrimethoxysilane and isobutyltrimethoxysiloxane dropwise to prepare different formulations , octyltrimethoxysiloxane, perfluorooctyltriethoxysilane and perfluorodecyltriethoxysilane, and continuously stirred for 24 hours to obtain a modified solution; in addition, 1.6 parts of hydrophilic silica nano powder, 2.3 parts of water-based propylsiloxane oligomer dispersed in 94 parts of deionized water, and continuously stirred at 50°C for 6 hours to obtain a modified solution; the hydrophilic silica described here is silica sol with a particle diameter of 4-10nm, adding Containing 0.5wt.% of KH550 aqueous solution, reacted under alkaline conditions for 6 hours and then dried; according to the weight ratio of 1:2.8, the pretreated activated carbon was soaked in different modified solutions, and after 10 minutes, vacuum at 75°C Rotate for 46 minutes, so that the modified solution is evenly wrapped on the activated carbon to obtain modified activated carbon; curing: take out the modified activated carbon and place it in an oven at 240°C for 3.5 hours to obtain the superhydrophobic activated carbon.

From the results of the moisture absorption test, it can be seen that using different non-fluorosilane modifiers (including water-based propylsilane) can prepare superhydrophobic activated carbon particles with excellent moisture resistance, and the increase in moisture absorption is significantly lower than that of fluorosilane modifiers. .

Example 10

Raw materials: Coal-based activated carbon powder with a moisture content of 2.0% is selected. Pretreatment: First, add 1.25 parts of polydimethylsiloxane (PDMS) to 48 parts of ethyl acetate, stir at room temperature for 10 minutes, then add 0.35 parts of hydrophobic silica nanopowder and 0.15 parts of butyl acetate and isocyanate mixture (mass Ratio 1:1) as the PDMS curing agent, continue to stir for 30min to obtain the pretreatment solution; the hydrophobic silica nano-powder described here is a commercial hydrophobic gas-phase nano-silica Hydrophobic-100 type; according to the weight ratio of 1:6, the Soak the activated carbon powder in the pretreatment solution, take it out after 5 minutes and dry it until there is no obvious moisture on the surface; modification: disperse 0.25 parts of polyether modified silicone leveling agent, 3.2 parts of ammonia water, and 1.7 parts of hydrophilic silica in 87 After stirring for 30 minutes at 50°C, add 0.35 parts of propyltrimethoxysilane and perfluorodecyltriethoxysilane dropwise, and keep stirring for 24 hours to obtain a modified solution; the hydrophilic dioxide mentioned here Silicon is silica sol with a particle diameter of 4-10nm, which is obtained by adding 0.5wt.% KH550 aqueous solution, reacting under alkaline conditions for 6 hours and then drying; according to the weight ratio of 1:1.7, soak the pretreated activated carbon into the modified solution After 10 minutes, rotate in vacuum at 65°C for 55 minutes, so that the modified solution is evenly wrapped on the activated carbon to obtain a modified activated carbon; curing: take out the modified activated carbon and place it in an oven at 230°C for 4 hours to obtain the superhydrophobic Activated carbon powder.

The moisture-proof effect of propylsilane-modified activated carbon powder is better than that of fluorosilane-modified activated carbon. The water droplets on the surface of the powder are obviously spherical, and the static contact angle is greater than 150°.

Example 11

Raw materials: use shell columnar activated carbon with a moisture content of 1.1%. Pretreatment: First, add 1.35 parts of polydimethylsiloxane (PDMS) to 46.5 parts of ethyl acetate, stir at room temperature for 10 minutes, then add 0.16 parts of hydrophobic silica nanopowder and 0.1 part of butyl acetate and isocyanate mixture (mass Ratio 1:1) as the PDMS curing agent, continue to stir for 30min to obtain the pretreatment solution; the hydrophobic silica nano-powder described here is a commercial hydrophobic gas-phase nano-silica Hydrophobic-100 type; according to the weight ratio of 1:6, the Soak the activated carbon particles in the pretreatment solution, take them out after 5 minutes and dry them until there is no obvious moisture on the surface; modification: disperse 0.18 parts of non-ionic fluorocarbon surfactant, 2.45 parts of ammonia water, and 1.36 parts of hydrophilic silica in 87.5 parts In deionized water, after stirring at 50°C for 30 minutes, add 0.25 parts of isobutyltrimethoxysilane dropwise, and continue stirring for 19 hours to obtain a modified solution; the hydrophilic silica described here is silica sol with a particle diameter of 4-10nm, and add Containing 0.5wt.% KH550 aqueous solution, reacted under alkaline conditions for 6 hours and then dried; according to the weight ratio of 1:1.85, the pretreated activated carbon was soaked into the modified solution, and after 10 minutes, it was rotated under vacuum at 76°C For 48 minutes, the modified solution was evenly wrapped on the activated carbon to obtain the modified activated carbon; curing: the modified activated carbon was taken out and placed in an oven at 235°C for 2.5 hours to obtain the superhydrophobic activated carbon.

After the modified activated carbon was kept at RH=99% or soaked in water for 10 days, it was taken out and placed at room temperature for 1 day, and the weight gain basically returned to 2%, while the unmodified activated carbon had less desorption and maintained a higher moisture absorption weight gain value.

Example 12

Raw materials: Coal-based columnar activated carbon with a moisture content of 1.7% is selected. Pretreatment: First, add 1.9 parts of polydimethylsiloxane (PDMS) to 48 parts of deionized water containing cationic fluorocarbon surfactants, stir at room temperature for 10 minutes, then add 0.85 parts of hydrophobic silica nanopowder and 0.19 parts of butyl acetate Ester and isocyanate mixed solution (mass ratio 1:1) is used as PDMS solidifying agent, and continuous stirring 30min can obtain pretreatment solution; The hydrophobic silica nanopowder described here is the commercial hydrophobic fumed nanosilica Hydrophobic-100 type; According to The weight ratio is 1:6, soak the activated carbon particles in the pretreatment solution, take it out after 10 minutes and dry it until there is no obvious moisture on the surface; disperse 1.65 parts of hydrophilic silica nano powder and 3.8 parts of water-based propylsiloxane In 93 parts of deionized water, continuously stirred at 50°C for 6h to obtain a modified solution; the hydrophilic silica described here is a silica sol with a particle diameter of 4-10nm, added to an aqueous solution of KH550 containing 0.5wt.%, under alkaline conditions According to the weight ratio of 1:2.6, the pretreated activated carbon was soaked into the modified solution, and after 6 minutes, it was rotated under vacuum at 55°C for 55 minutes, so that the modified solution was evenly wrapped on the activated carbon, and the modified solution was obtained. Activated carbon; curing: the modified activated carbon is taken out and placed in an oven at 240°C for 1 hour to obtain the superhydrophobic activated carbon.

After the modified superhydrophobic activated carbon undergoes high humidity or soaking in water to absorb moisture, it desorbs at room temperature, releases the adsorbed water vapor, and can perform multiple continuous cycles, while the unmodified activated carbon has poor desorption performance.

Example 13

Raw materials: Wooden columnar activated carbon with a moisture content of 1.9% is selected. Pretreatment: First, add 1.65 parts of polydimethylsiloxane (PDMS) to 44.5 parts of deionized water containing silicone leveling agent, stir at room temperature for 10 minutes, then add 0.45 parts of hydrophobic silica nanopowder and 0.2 parts of butyl acetate Mixed liquid with isocyanate (mass ratio 1:1) as PDMS solidifying agent, can obtain pretreatment solution by continuous stirring for 30min; Hydrophobic silica nanopowder described here is commercial hydrophobic fumed nanosilica Hydrophobic-100 type; Ratio 1:6, soak the activated carbon particles in the pretreatment solution, take it out after 8 minutes and dry it until there is no obvious moisture on the surface; modification: 1.85 parts of hydrophilic silica nanopowder, 3.5 parts of water-based propyl siloxane oligomerization The compound was dispersed in 88.5 parts of deionized water, and continuously stirred at 50°C for 4.5h to obtain a modified solution; the hydrophilic silica described here was a silica sol with a particle diameter of 4-10nm, and was added to an aqueous solution of KH550 containing 0.5wt.%. It is obtained by drying after reacting for 6 hours under alkaline conditions; according to the weight ratio of 1:2.4, the pretreated activated carbon is soaked into the modified solution, and after 8 minutes, it is rotated under vacuum at 68°C for 60 minutes, so that the modified solution is evenly wrapped on the activated carbon. , to obtain modified activated carbon; curing: the modified activated carbon was taken out and placed in an oven at 240° C. for 30 min to obtain the superhydrophobic activated carbon.

After the modified superhydrophobic activated carbon undergoes high humidity or soaking in water to absorb moisture, the CTC decreases less, and after one day of desorption, the CTC almost returns to the initial state, while the unmodified activated carbon decreases greatly, and almost drops to 0 after soaking in water. .

Example 14

Raw materials: Wooden columnar activated carbon with a moisture content of 1.8% is selected. Pretreatment: First, add 1.3 parts of polydimethylsiloxane (PDMS) to 41 parts of deionized water containing non-ionic fluorocarbon surfactants, stir at room temperature for 10 minutes, then add 0.13 parts of hydrophobic silica nanopowder and 0.13 parts of acetic acid The mixed solution of butyl ester and isocyanate (mass ratio 1:1) is used as PDMS curing agent, and the pretreatment solution can be obtained by continuous stirring for 30 minutes; the hydrophobic silica nano-powder described here is commercial hydrophobic fumed nano-silica Hydrophobic-100 type; According to the weight ratio of 1:6, soak the activated carbon particles in the pretreatment solution, take it out after 7 minutes and dry it until there is no obvious moisture on the surface; modification: 1.4 parts of hydrophilic silica nanopowder, 3.7 parts of water-based propylsiloxane The oligomer was dispersed in 93 parts of deionized water, and continuously stirred at 50°C for 5.5h to obtain a modified solution; the hydrophilic silica described here was a silica sol with a particle diameter of 4-10nm, which was added to an aqueous solution of KH550 containing 0.5wt.% , obtained by drying after reacting for 6 hours under alkaline conditions; according to the weight ratio of 1:2, soak the pretreated activated carbon into the modification solution, and after 10 minutes, vacuum rotate at 65°C for 55 minutes, so that the modification solution is evenly wrapped in the On the activated carbon, the modified activated carbon was obtained; curing: the modified activated carbon was taken out and placed in an oven at 220°C for 2 hours to obtain the superhydrophobic activated carbon.

The modified superhydrophobic activated carbon has a good selective adsorption of edible oil mist under the condition of RH=90%, and the weight gain of oil mist adsorption is obviously better than that of unmodified activated carbon.

Example 15

Raw materials: use shell columnar activated carbon with a moisture content of 1.5%. Pretreatment: first add 2 parts of polydimethylsiloxane (PDMS) to 50 parts of deionized water containing polyether modified silicone leveling agent, stir at room temperature for 10 minutes, then add 0.16 parts of hydrophobic silica nanopowder and 0.2 One part of butyl acetate and isocyanate mixed solution (mass ratio 1:1) is used as PDMS curing agent, and the pretreatment solution can be obtained by continuous stirring for 30 minutes; the hydrophobic silica nano powder described here is commercial hydrophobic fumed nano silica Hydrophobic-100 type; according to the weight ratio of 1:6, soak the activated carbon particles in the pretreatment solution, take it out after 10 minutes and dry it until there is no obvious moisture on the surface; modification: 0.28 parts of cationic fluorocarbon surfactant, 3.4 parts of ammonia water, 1.7 parts Hydrophilic silica is dispersed in 95 parts of deionized water, stirred at 50°C for 30 minutes, then 0.25 parts of octyltrimethoxysilane is added dropwise, and stirred continuously for 24 hours to obtain a modified solution; the hydrophilic silica described here is particle Silica sol with a diameter of 4-10nm is added to the KH550 aqueous solution containing 0.5wt.%, and it is obtained by drying under alkaline conditions for 6 hours; according to the weight ratio of 1:1.8, soak the pretreated activated carbon into the modified solution, and after 8 minutes , rotate in vacuum at 75°C for 45 minutes, so that the modified solution is evenly wrapped on the activated carbon to obtain modified activated carbon; curing: take out the modified activated carbon and place it in an oven at 210°C for 3.5 hours to obtain the superhydrophobic activated carbon.

The modified superhydrophobic activated carbon has a good COD removal effect on the edible soybean oil microemulsion and DMF solution, while the COD removal rate of the unmodified activated carbon is much lower than that of the modified activated carbon.

Example 16

Raw materials: Coal-based columnar activated carbon with a moisture content of 1.5% is selected. Pretreatment: First, add 1.85 parts of polydimethylsiloxane (PDMS) to 50 parts of ethyl acetate, stir at room temperature for 10 minutes, then add 0.56 parts of hydrophobic silica nanopowder and 0.17 parts of butyl acetate and isocyanate mixed solution (mass Ratio 1:1) as the PDMS curing agent, continue to stir for 30min to obtain the pretreatment solution; the hydrophobic silica nano-powder described here is a commercial hydrophobic gas-phase nano-silica Hydrophobic-100 type; according to the weight ratio of 1:6, the Soak the activated carbon particles in the pretreatment solution, take them out after 5 minutes and dry them until there is no obvious moisture on the surface; modification: disperse 1.76 parts of hydrophilic silica nanopowder, 2.85 parts of water-based propylsiloxane oligomer in 82 parts In ionized water, keep stirring at 50°C for 5 hours to obtain a modified solution; the hydrophilic silica described here is a silica sol with a particle diameter of 4-10nm, which is added to an aqueous solution of KH550 containing 0.5wt.%, and reacted for 6 hours under alkaline conditions Obtained by drying; according to the weight ratio of 1:2.8, soak the pretreated activated carbon into the modified solution, and after 10 minutes, rotate it under vacuum at 75°C for 48 minutes, so that the modified solution is evenly wrapped on the activated carbon to obtain modified activated carbon; solidify : The superhydrophobic activated carbon can be obtained by taking out the modified activated carbon and placing it in an oven at 245° C. for curing for 45 minutes.

The modified superhydrophobic activated carbon has a continuous and efficient removal effect on COD of edible soybean oil microemulsion and DMF solution, and its service life is greatly improved compared with the unmodified activity.

Example 17

Raw materials: wooden columnar activated carbon with a moisture content of 1.0% is selected. Pretreatment: First, add 1.25 parts of polydimethylsiloxane (PDMS) to 47 parts of ethyl acetate, stir at room temperature for 10 minutes, then add 0.16 parts of hydrophobic silica nanopowder and 0.15 parts of butyl acetate and isocyanate mixed solution (mass ratio 1:1) as a PDMS curing agent, the pretreatment solution can be obtained by continuous stirring for 30 minutes; the hydrophobic silica nanopowder described here is a commercial hydrophobic gas phase nano-silica Hydrophobic-100 type; according to the weight ratio of 1:6, the activated carbon Soak the particles in the pretreatment solution, take them out after 7 minutes and dry them until there is no obvious moisture on the surface; modification: disperse 1.9 parts of hydrophilic silica nanopowder, 4.7 parts of water-based propylsiloxane oligomer in 97 parts of deionized In water, keep stirring at 50°C for 6 hours to obtain a modified solution; the hydrophilic silica described here is a silica sol with a particle diameter of 4-10 nm, which is added to an aqueous solution of KH550 containing 0.5 wt.%, reacted under alkaline conditions for 6 hours, and then dried Obtained; according to the weight ratio of 1:2.6, the pretreated activated carbon was soaked into the modified solution, and after 8 minutes, it was rotated in vacuum at 80°C for 45 minutes, so that the modified solution was evenly wrapped on the activated carbon to obtain modified activated carbon; curing: The superhydrophobic activated carbon can be obtained by taking out the modified activated carbon and placing it in an oven at 250° C. for curing for 30 minutes.

The modified superhydrophobic activated carbon has a high removal rate of toluene and DMF under the condition of RH=90% and hot steam, while the removal efficiency of the unmodified activated carbon is obviously reduced.

Example 18

Raw materials: Use fruit shell columnar activated carbon with a moisture content of 1.2%. Pretreatment: First, add 1.48 parts of polydimethylsiloxane (PDMS) to 45.5 parts of deionized water containing polyether modified silicone leveling agent, stir at room temperature for 10 minutes, then add 0.87 parts of hydrophobic silica nanopowder and 0.15 One part of butyl acetate and isocyanate mixed solution (mass ratio 1:1) is used as PDMS curing agent, and the pretreatment solution can be obtained by continuous stirring for 30 minutes; the hydrophobic silica nano powder described here is commercial hydrophobic fumed nano silica Hydrophobic-100 type; according to the weight ratio of 1:6, soak the activated carbon particles in the pretreatment solution, take it out after 10 minutes and dry it until there is no obvious moisture on the surface; modification: mix 0.36 parts of silicone leveling agent, 2.8 parts of ammonia water, 1.7 parts of hydrophilic Silica was dispersed in 87 parts of deionized water, and after stirring at 50°C for 30 minutes, 0.45 parts of octyltrimethoxysilane was added dropwise, and the stirring was continued for 22 hours to obtain a modified solution; the hydrophilic silica described here had a particle diameter of 4 -10nm silica sol, added to the KH550 aqueous solution containing 0.5wt.%, and obtained by drying under alkaline conditions for 6 hours; according to the weight ratio of 1:2.7, soak the pretreated activated carbon into the modified solution, and after 10 minutes, in Vacuum rotation at 78°C for 45 minutes, so that the modified solution is evenly wrapped on the activated carbon to obtain modified activated carbon; curing: take out the modified activated carbon and place it in an oven at 210°C for 4 hours to obtain the superhydrophobic activated carbon.

The modified superhydrophobic activated carbon maintains a high removal rate of toluene and DMF under the conditions of RH=90% and hot steam, and its service life is significantly improved compared with the original activated carbon.

Example 19

Raw materials: Coal-based columnar activated carbon with a moisture content of 1.0% is selected. Pretreatment: First, add 1.84 parts of polydimethylsiloxane (PDMS) to 47 parts of deionized water containing non-ionic fluorocarbon surfactants, stir at room temperature for 10 minutes, then add 0.16 parts of hydrophobic silica nanopowder and 0.16 parts of The mixed solution of butyl acetate and isocyanate (mass ratio 1:1) is used as the PDMS curing agent, and the pretreatment solution can be obtained by continuous stirring for 30 minutes; the hydrophobic silica nano-powder described here is commercial hydrophobic fumed nano-silica Hydrophobic-100 ;According to the weight ratio of 1:6, soak the activated carbon particles in the pretreatment solution, take it out after 10min and dry it until there is no obvious moisture on the surface; modification: 0.38 parts of non-ionic fluorocarbon surfactant, 2.8 parts of ammonia water, 1.7 parts Hydrophilic silica was dispersed in 89 parts of deionized water, stirred at 50°C for 30 minutes, then 0.5 parts of propyltrimethoxysilane was added dropwise, and stirred continuously for 24 hours to obtain a modified solution; the hydrophilic silica described here was granule Silica sol with a diameter of 4-10nm is added to an aqueous solution of KH550 containing 0.5wt.%, reacted under alkaline conditions for 6 hours and then dried; according to the weight ratio of 1:2.6, soak the pretreated activated carbon into the modified solution, and after 10 minutes , rotate in vacuum at 58°C for 50 minutes, so that the modified solution is evenly wrapped on the activated carbon to obtain modified activated carbon; curing: take out the modified activated carbon and place it in an oven at 246°C to cure for 45 minutes to obtain the superhydrophobic activated carbon.

After the modified superhydrophobic activated carbon was removed from COD and VOC, after high-temperature regeneration treatment, the CTC almost returned to the original state, and the regenerability was good.

Claims

A preparation method of fluorine-free waterproof and moisture-proof superhydrophobic activated carbon, characterized in that the preparation steps are:

(1) Raw materials: activated carbon is selected as one of coal, wood, and shell activated carbon, and the moisture content is not higher than 2wt.%.

(2) Pretreatment: first add 1-2 parts of polydimethylsiloxane (PDMS) to 40-50 parts of ethyl acetate or deionized water containing surfactants, stir at room temperature and then add 0.1-1 parts of hydrophobic dimethicone Silicon oxide nanopowder and 0.1-0.2 part of PDMS curing agent, continue to stir to obtain the pretreatment solution; Soak activated carbon in the pretreatment solution, take it out and dry after 5-10min; The mass content of the surfactant in deionized water is 0.2-0.5%; the hydrophobic silica nanopowder is obtained by drying silica sol or fumed silica grafted with a hydrophobic group with a particle diameter of 4-10nm, and the hydrophobic group is methyl, propyl, isobutyl or octyl;

(3) Modification: Disperse 0.1-0.5 parts of surfactant, 2-4 parts of ammonia water, and 1-2 parts of hydrophilic silica in 80-100 parts of deionized water, stir at 50°C for 30 minutes, and then add dropwise 0.2-0.5 parts of modifier, keep stirring for 16-24 hours to obtain a modified solution; or directly disperse 1-2 parts of hydrophilic silica nanopowder, 1-5 parts of water-based alkyl siloxane oligomer in 80- 100 parts of deionized water, continuously stirred at 50°C for 4-6 hours to obtain a modified solution; soak the pretreated activated carbon into the modified solution, and the mass ratio of activated carbon to modified solution is 1: (1.5-3), 5- After 10 minutes, rotate in vacuum at 50-80°C for 45-60 minutes to obtain modified activated carbon; the hydrophilic silica is obtained by grafting KH550 silane coupling agent groups on silica sol with a particle diameter of 4-10 nm and drying; the obtained The modifying agent is a fluorine-free alkyl siloxane with a carbon chain length greater than 3, and the content in the modified solution is 1wt.%-10wt.%; the water-based alkyl siloxane oligomer is water-based isobutyl base silicone, waterborne octylsiloxane or waterborne propylsiloxane;

(4) Curing: Take out the modified activated carbon and put it in an oven at 200-250°C to cure for 30min-4h to obtain fluorine-free waterproof and moisture-proof superhydrophobic activated carbon.
The preparation method of the fluorine-free waterproof and moisture-proof superhydrophobic activated carbon according to claim 1, wherein the fluorine-free alkyl siloxane is isobutyl siloxane, octyl siloxane or propyl siloxane.
According to the preparation method of the described fluorine-free waterproof and moisture-proof super-hydrophobic activated carbon of claim 2, it is characterized in that, the modifier is a fluorine-free alkyl siloxane stock solution, or the solvent is a fluorine-free alkyl siloxane dilution of n-hexane liquid.
According to the preparation method of the described fluorine-free waterproof and moisture-proof superhydrophobic activated carbon of claim 1, it is characterized in that, the surfactant is polyether modified silicone leveling agent, cationic fluorocarbon surfactant or nonionic fluorocarbon Surfactant.
The fluorine-free waterproof and moisture-proof super-hydrophobic activated carbon prepared by the preparation method described in any one of claims 1-4.
The fluorine-free waterproof and moisture-proof super-hydrophobic activated carbon according to claim 5, is characterized in that, in a relative humidity of 60-99% environment or standing in water for 24h, moisture absorption or water absorption weight gain is less than 10%, and the relative humidity is 60% -99% environment or water for 90 days, moisture absorption or water absorption weight gain is less than 20%; compared with untreated activated carbon, superhydrophobic activated carbon can still efficiently adsorb organic matter in moisture or water, and the adsorption efficiency is increased by more than 95%, and Heating in vacuum at 100°C for 30 minutes, more than 90% of the adsorbed substances can be desorbed.
The application of the fluorine-free waterproof and moisture-proof superhydrophobic activated carbon described in claim 5 in the preparation and removal of COD and VOC products.