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CN-121988287-A - Low-pore-blocking high-strength honeycomb activated carbon and preparation method thereof

CN121988287ACN 121988287 ACN121988287 ACN 121988287ACN-121988287-A

Abstract

The invention relates to the technical field of activated carbon materials, and discloses a low-pore-blocking high-strength honeycomb activated carbon and a preparation method thereof; the honeycomb activated carbon comprises activated carbon particle skeletons and bonding networks filled among the activated carbon particle skeletons, wherein the bonding networks are formed by heat treatment and solidification of a bi-component crosslinking adhesive system, the bi-component crosslinking adhesive system comprises a copolymerization emulsion adhesive A and a powder adhesive B, active functional groups in the copolymerization emulsion components and organic acids in the powder components are subjected to esterification crosslinking reaction under the action of heat, so that a three-dimensional crosslinking network structure is formed among the activated carbon particles, bridging connection is constructed, the honeycomb activated carbon has a higher iodine adsorption value and axial compressive strength, and the integral mechanical strength of the honeycomb activated carbon is improved while the micropore structure of the activated carbon is maintained by constructing a composite structure with the synergistic effect of the particle skeletons and the crosslinking bonding networks, and the pore blocking phenomenon is reduced.

Inventors

  • LIU GUOLIANG

Assignees

  • 佛山市三水泰鑫合成材料有限公司

Dates

Publication Date
20260508
Application Date
20260316

Claims (10)

  1. 1. The honeycomb activated carbon with low pore blocking and high strength is characterized by comprising activated carbon particle frameworks and bonding networks filled among the activated carbon particle frameworks, wherein the bonding networks are formed by heat treatment and solidification of a bi-component crosslinking adhesive system; the honeycomb activated carbon has a three-dimensional crosslinked network structure, and the structure is formed by esterification crosslinking reaction of active functional groups in the copolymerization emulsion component and organic acid in the powder component under the action of heat, so that bridging connection is formed between activated carbon particles; the iodine adsorption value of the honeycomb activated carbon is 950-1050 mg/g, the axial compressive strength is more than or equal to 2.0 MPa, and the honeycomb activated carbon has the characteristic of water-resistant bubbles and non-dispersion; the bonding network is mainly distributed in the contact area of the active carbon particles, and a thinner or discontinuous adhesive layer is formed on the surface of the micropore channel.
  2. 2. The honeycomb activated carbon with low pore blocking and high strength according to claim 1, wherein the raw materials of the activated carbon particle skeleton comprise at least one of coconut shell activated carbon powder, coal activated carbon, bamboo charcoal powder or wood activated carbon powder, and the particle size distribution of the raw materials is 200-325 meshes; the bonding network is prepared by mixing, forming and thermally crosslinking the following raw materials in parts by weight: 100 parts of active carbon powder; 15-30 parts of a two-component adhesive system; 70-85 parts of water; The bi-component adhesive system is formed by mixing a copolymer emulsion adhesive A, a powder adhesive B and water.
  3. 3. The honeycomb activated carbon with low pore blocking and high strength according to claim 2, wherein the copolymer emulsion adhesive A is a copolymer emulsion containing polyvinyl alcohol, vinyl acetate, acrylic acid and N-methylol acrylamide; The powder adhesive B comprises citric acid, sodium carboxymethyl cellulose, kaolin, sepiolite powder and silicon-aluminum filler; The three-dimensional crosslinked network structure comprises ester bond crosslinking points formed by the reaction of citric acid carboxyl in the powder adhesive B and hydroxyl and N-hydroxymethyl in the copolymer emulsion adhesive A.
  4. 4. The low-pore-blocking high-strength honeycomb activated carbon according to claim 3 is characterized in that the powder adhesive B comprises, by mass, 3% -6% of citric acid, 1% -3% of sodium carboxymethyl cellulose, 25% -40% of kaolin, 15% -25% of sepiolite powder, 15% -25% of silicon-aluminum filler and 600-1200 meshes of powder adhesive B.
  5. 5. The honeycomb activated carbon with low pore blocking and high strength according to claim 1, wherein the honeycomb activated carbon has a gradient distribution structure in microcosmic, the bonding network is mainly concentrated in the contact area of activated carbon particles and the inside of the honeycomb wall body to form a framework support, and the adhesive layer formed on the surfaces of micropore channels of the activated carbon particles is thinner or discontinuous; The surface of the active carbon particles is also distributed with a secondary micropore structure formed by thermal decomposition or volatilization of the micropore protective agent.
  6. 6. A method for preparing the low-blocking high-strength honeycomb activated carbon according to any one of claims 1 to 5, comprising the following steps: s1, active carbon powder pretreatment, namely selecting active carbon powder raw materials, controlling the particle size, drying, and regulating the water content; s2, preparing a copolymer emulsion adhesive A, namely performing emulsion polymerization reaction by taking polyvinyl alcohol as a protective colloid and vinyl acetate, acrylic acid and N-methylol acrylamide as monomers; s3, preparing a powder adhesive B, namely uniformly mixing citric acid, sodium carboxymethyl cellulose and inorganic mineral filler; s4, constructing a bi-component adhesive system, namely mixing the copolymer emulsion adhesive A, water and the powder adhesive B in proportion to prepare uniform colloid; s5, mixing and molding, namely mixing the pretreated activated carbon powder with a bi-component adhesive system and water, homogenizing the mixture, and extruding the mixture to obtain a honeycomb blank; S6, sectional heat treatment and solidification, namely sectional drying and heating heat treatment are carried out on the green body, and a crosslinking reaction is initiated, so that the honeycomb activated carbon with low blocking holes and high strength is prepared.
  7. 7. The preparation method of claim 6, wherein in the step S1, a micropore protective agent with the mass fraction of 0.5% -2% is added into the activated carbon powder, the micropore protective agent is selected from bicarbonate, thermally decomposable organic matters or volatilizable pore-forming substances, and the water content of the activated carbon powder after drying is controlled to be 3% -6%.
  8. 8. The method according to claim 6, wherein in the step S2, the mass ratio of the vinyl acetate, the acrylic acid and the N-methylol acrylamide in the comonomer is 100:4-10:5-15, the solid content of the finally prepared copolymer emulsion adhesive A is 35-40%, and the viscosity is 6000-10000 mPa.s.
  9. 9. The preparation method of the adhesive according to claim 6, wherein in the step S4, the preparation proportion of the two-component adhesive system is that the copolymerized emulsion adhesive A accounts for 10% -20%, the water accounts for 70% -80%, the powder adhesive B accounts for 5% -10%, and the viscosity of the mixed two-component adhesive system is controlled to be 2000-5000 mPa.s.
  10. 10. The method according to claim 6, wherein the step S6 is a step of heat-treating the mixture at 80 ℃ for 30 minutes, at 100 ℃ for 30 minutes, at 130 ℃ for 60 minutes, and at 150 to 160 ℃ for 60 minutes, wherein the step 150 to 160 ℃ is used for initiating the esterification crosslinking curing reaction.

Description

Low-pore-blocking high-strength honeycomb activated carbon and preparation method thereof Technical Field The invention relates to the technical field of activated carbon materials, in particular to a low-pore-blocking high-strength honeycomb activated carbon and a preparation method thereof. Background The honeycomb activated carbon is a porous adsorption material with a regular honeycomb pore structure, and is generally prepared by mixing activated carbon powder through a binder, extrusion molding and curing treatment. Because of the advantages of large specific surface area, small gas channel resistance, high adsorption efficiency and the like, the honeycomb activated carbon is widely applied to the fields of industrial waste gas treatment, volatile Organic Compound (VOC) adsorption treatment, air purification and the like. Compared with the traditional granular activated carbon or columnar activated carbon, the honeycomb activated carbon can remarkably reduce the gas flow resistance while maintaining higher adsorption performance, so that the honeycomb activated carbon has good application prospect in large-air-volume gas purification equipment. In the prior art, in order to enable the activated carbon powder to form a stable honeycomb structure, it is generally necessary to add a certain amount of binder to the carbon powder, and cure the structure by drying or heat treatment after extrusion molding. Common binders include polyvinyl alcohol, starch-based binders, inorganic binders or composite systems thereof. Such binders are capable of forming a cohesive bond between the carbon particles to some extent, thereby imparting substantial mechanical strength to the honeycomb structure. However, in practical applications, the conventional bonding systems described above still have some drawbacks. For example, when the amount of binder is low, the honeycomb activated carbon is liable to have problems of insufficient structural strength, powder falling or breakage during use, and when the amount of binder is increased to improve strength, the binder easily enters the inside of the microporous structure of the activated carbon, thereby blocking the pore channels and reducing the specific surface area and adsorption performance of the material. In addition, in the process of honeycomb activated carbon molding and heat treatment, as the carbon particles are connected by physical adhesion or simple bonding, the particles lack stable chemical crosslinking structures, so that the stability of the whole structure still has room for further improvement. Meanwhile, the problems of loose local structure, insufficient compressive strength, pulverization after long-term use and the like of the existing honeycomb activated carbon can also occur in the heat treatment or use process, so that the application effect of the honeycomb activated carbon in the fields of industrial waste gas treatment and the like is limited to a certain extent. Therefore, how to improve the overall structural strength of the honeycomb activated carbon and reduce the blocking phenomenon of the pore canal on the premise of keeping the microporous structure and the adsorption performance of the activated carbon as much as possible is a technical problem to be solved in the field. Disclosure of Invention The first aspect of the invention is to provide a honeycomb activated carbon with low pore blocking and high strength, and the whole prepared honeycomb activated carbon is composed of an activated carbon particle skeleton structure and a bonding network structure filled among particles. The activated carbon particle skeleton is formed by mixing, forming and solidifying activated carbon powder with the particle size of 200-325 meshes to form a continuously distributed porous particle supporting structure, and a plurality of activated carbon particles are contacted with each other in the honeycomb wall body to form a stable particle stacking skeleton. The bond network is distributed in the contact area between adjacent activated carbon particles and forms a bridging connection between the particles, thereby securing the plurality of particles as a unitary structure. Through the structural design, the honeycomb activated carbon not only maintains the original microporous structure of the activated carbon particles, but also can form a stable integral honeycomb framework on a macroscopic scale, thereby improving the integral mechanical strength of the material and reducing the powder falling phenomenon. Further, the bonding network in the present invention is formed by curing a two-component cross-linked adhesive system by heat treatment. The two-component crosslinking adhesive system comprises a copolymerization emulsion adhesive A and a powder adhesive B, and the copolymerization emulsion adhesive A and the powder adhesive B can undergo a crosslinking reaction under the action of heat after being mixed, so that a stable three-dimensional network struct