Activated carbon supported cof composite adsorbent material and preparation method thereof

Abstract

The application provides an activated carbon loaded COF composite adsorption material and a preparation method thereof. The activated carbon loaded COF composite adsorption material is prepared by loading specific covalent organic framework material on a granular wood activated carbon substrate, forming chemical bonding with target waste gas molecules by using sulfonic acid groups or amino functional groups, realizing the synergistic effect of physical adsorption and chemical adsorption, effectively solving the problems of low selectivity, low adsorption capacity and short service life of traditional adsorption materials for inorganic acid and alkali waste gas, and having high selective adsorption capacity and high adsorption capacity. Meanwhile, the excellent chemical stability and structural integrity of the covalent organic framework enable the adsorption sites to be effectively maintained during the multiple adsorption-desorption cycle process, thereby endowing the activated carbon loaded COF composite adsorption material with long service life, long cycle life and economic feasibility.

Description

Technical Field

[0001] This application relates to the field of adsorption materials technology, specifically to an activated carbon-supported COF composite adsorption material and its preparation method. Background Technology

[0002] For a long time, industrial waste gas purification and household air purification have relied on commercial activated carbon as the primary adsorption medium, including coal-based activated carbon, coconut shell activated carbon, and honeycomb activated carbon. These traditional activated carbon materials capture gaseous pollutants through physical adsorption due to their well-developed pore structure and large pore volume. However, because the surface of activated carbon contains only a small number of naturally occurring oxygen-containing heteroatom functional groups and lacks customized active site design, its adsorption capacity for low-concentration inorganic acid and alkali waste gases is fundamentally limited.

[0003] In practical applications, these materials, relying solely on physical adsorption mechanisms, have significantly insufficient adsorption capacity for target pollutants such as ammonia, sulfur dioxide, and hydrogen sulfide. They easily reach saturation quickly, and once saturated, the porous materials become ineffective. Alternatively, they require frequent regeneration, drastically shortening their lifespan. Or they lack the practicality for recycling, leading to significant waste and high replacement costs. Furthermore, traditional activated carbon exhibits a marked decrease in removal efficiency under low-temperature or low-concentration conditions due to the lack of specific chemical adsorption sites, failing to meet the stringent requirements of modern industrial waste gas treatment and household air purification.

[0004] Meanwhile, covalent organic frameworks (COFs), as a novel type of porous crystalline material, theoretically possess the potential for highly efficient adsorption of acidic and alkaline gases due to their ultra-high specific surface area, precisely tunable pore structure, and high-density functional group sites. Single-amino or sulfonic acid-based COF crystalline materials exhibit superior adsorption performance compared to traditional activated carbon through the chemical interactions between their specific functional groups and target gas molecules. However, pure COF materials face significant challenges in practical applications: the high cost of their synthesis raw materials limits their overall economic viability; simultaneously, the slow mass transfer rate of COF materials makes them unsuitable for the high-flow, continuous operation requirements of industrial waste gas and household air purification systems. These issues hinder the large-scale application of pure COF materials in waste gas purification equipment, limiting their practical engineering value.

[0005] In other words, single activated carbon materials cannot provide enough chemisorption sites to achieve selective and efficient capture of specific inorganic acid and alkali waste gases, while pure COF materials are difficult to apply on a large scale due to cost and mass transfer issues. The existing technological system lacks a solution that can simultaneously achieve high adsorption capacity, good selectivity, rapid mass transfer performance, and economic feasibility, making it difficult to effectively control inorganic acid and alkali pollutants in industrial waste gases, automotive cabin air, and indoor environments.

[0006] Especially when treating low-concentration inorganic acid and alkali waste gases, existing adsorption materials often exhibit problems such as insufficient adsorption capacity, poor selectivity, and short service life, failing to meet increasingly stringent environmental standards and practical application requirements. Summary of the Invention

[0007] The purpose of this application is to provide an activated carbon-supported COF composite adsorbent material and its preparation method. The activated carbon-supported COF composite adsorbent material has high selective adsorption capacity, high adsorption capacity, long service life and economic feasibility.

[0008] To achieve the above-mentioned objectives, this invention provides an activated carbon-supported COF composite adsorbent material for the selective adsorption of inorganic acid and alkali waste gases. The activated carbon-supported COF composite adsorbent material comprises:

[0009] Granular wood-based activated carbon substrate: The granular wood-based activated carbon has a multi-level pore structure, and the pore size distribution of the granular wood-based activated carbon substrate is 2~50nm, and the specific surface area is 900~1200m² / g.

[0010] Specific covalent organic framework material: loaded on the surface and within the pores of the granular wood-based activated carbon; the specific covalent organic framework material is a sulfonic acid group covalent organic framework material with sulfonic acid functional groups or an amino group covalent organic framework material with amino functional groups.

[0011] In the activated carbon-supported COF composite adsorbent material, the specific covalent organic framework material has a mass content of 0.01~20wt%.

[0012] To achieve the above-mentioned objectives, the present invention also provides a method for preparing activated carbon-supported COF composite adsorbent materials, the method comprising:

[0013] Pretreatment of granular wood-based activated carbon:

[0014] Preparation of specific covalent organic framework materials: Based on the type of waste gas to be adsorbed, specific functional groups are selected, and specific covalent organic framework materials for selective adsorption of inorganic acid and alkali waste gases are prepared by reaction.

[0015] Loading of specific covalent organic framework material: A dispersion of the specific covalent organic framework material is prepared, and the pretreated granular wood-based activated carbon is impregnated in the dispersion; wherein the mass ratio of the granular wood-based activated carbon to the specific covalent organic framework material is (5~15):(85~95); the initial activated carbon-loaded COF composite adsorbent material is prepared.

[0016] Post-processing of activated carbon-supported COF composite adsorbent material: The initial activated carbon-supported COF composite adsorbent material is dried to obtain the activated carbon-supported COF composite adsorbent material.

[0017] As a further improvement of the present invention, the pretreatment of the granular wood-based activated carbon specifically includes:

[0018] Washing: Soak the granular wood-based activated carbon in deionized water and stir for 0.5 to 2 hours, then overflow and rinse until the effluent is clear;

[0019] Acid washing: Use 2~5wt% dilute hydrochloric acid, solid-liquid ratio 1:4~1:6, temperature 60~90℃, and soak and cook the granular wood-based activated carbon after water washing at a constant temperature for 1~3 hours.

[0020] Rinsing: The granular wood-based activated carbon is rinsed with multi-stage pure water until the pH of the filtrate is between 6.5 and 7.5 and there is no chloride ion residue.

[0021] Drying: The rinsed granular wood-based activated carbon is dried at a drying temperature of 80~100℃ for 4~8 hours.

[0022] As a further improvement of the present invention, the specific covalent organic framework material includes a sulfonic acid-based covalent organic framework material for adsorbing alkaline waste gases and an amino-based covalent organic framework material for adsorbing acidic waste gases.

[0023] As a further improvement of the present invention, the preparation of the sulfonic acid-based covalent organic framework material includes: reacting 2,5-diaminobenzene-1,4-disulfonic acid with trialdehyde-resorcinol and flux in a molar ratio of 1:(1.3-1.4):(3-10).

[0024] As a further improvement of the present invention, the preparation of the amino covalent organic framework material includes: reacting 2,5-bis((5-aminopentyl)oxy)-terephthalaldehyde with 1,3,6,8-tetra-(p-aminophenyl)pyrene and flux in a molar ratio of (2-4):(1-1.5):(4-12).

[0025] As a further improvement of the present invention, after the preparation of the specific covalent organic framework material is completed, the method further includes a thermal activation post-treatment of the specific covalent organic framework material, wherein the thermal activation post-treatment specifically comprises:

[0026] Immersion washing: The specific covalent organic framework material was immersed and washed using an ethanol / water mixed solvent;

[0027] Dehydration and drying: The specific covalent organic framework material after soaking and cleaning is dried at a drying temperature of 100±5℃ for 2h±10min to remove moisture from the specific covalent organic framework material;

[0028] Thermal activation treatment: The specific covalent organic framework material is thermally activated in an inert atmosphere for 1-2 hours.

[0029] As a further improvement of the present invention, in the thermal activation process:

[0030] When the specific covalent organic framework material is a sulfonic acid-based covalent organic framework material used for alkaline waste gas adsorption, the thermal activation temperature is 100~180℃.

[0031] When the specific covalent organic framework material is an amino-covalent organic framework material used for adsorption of acidic waste gas, the thermal activation temperature is 150~250℃.

[0032] As a further improvement of the present invention, the loading of the specific covalent organic framework material is specifically as follows:

[0033] Obtaining the powder: The specific covalent organic framework material is ground and sieved to a fine powder with a particle size of 50-100 μm;

[0034] Preparation of dispersion: The fine powder of the specific covalent organic framework material and the dispersant are mixed in a sand mill at a mass ratio of 5:95 and milled at a speed of 1500±10 r / min for 4±0.5 h to prepare the dispersion; wherein the dispersant is a compound solution of organic solvent and water, and the proportion of water is 10~40%.

[0035] As a further improvement of the present invention, in the loading process of the specific covalent organic framework material, the pretreated granular wood-based activated carbon is impregnated in the dispersion by segmented heating according to a temperature gradient of 30→50→70℃, stirring the pretreated granular wood-based activated carbon and the dispersion at a speed of 100-300r / min, and impregnating at a constant temperature for 0.5-24h.

[0036] The beneficial effects of this application are as follows:

[0037] By loading specific covalent organic framework materials onto granular wood-based activated carbon substrates, the sulfonic acid or amino functional groups of these materials form chemical bonds with target waste gas molecules, achieving a synergistic effect of physical and chemical adsorption. Furthermore, the activated carbon-supported COF composite adsorbent provided in this application, thanks to its stable covalent organic framework structure and chemically bonded active sites, can recover its adsorption activity after appropriate desorption treatment following adsorption saturation, enabling regeneration and reuse. Thus, while maintaining excellent adsorption performance, the activated carbon-supported COF composite adsorbent is also recyclable, resulting in a longer service life and cycle life, high selective adsorption capacity, high adsorption capacity, and economic feasibility. This effectively solves the problems of insufficient selectivity, low adsorption capacity, and short service life of traditional adsorbent materials for inorganic acid and alkali waste gases. Attached Figure Description

[0038] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0039] Figure 1 This is a flowchart illustrating the preparation method of the activated carbon-supported COF composite adsorbent material of the present invention.

[0040] Figure 2 This is a synthetic route diagram of COF-SO3H in Example 1;

[0041] Figure 3 The image shows the FT-IR spectrum of COF-SO3H in Example 1.

[0042] Figure 4 The image shows the XRD pattern of C-COF-SO3H in Example 1.

[0043] Figure 5 This is a STEM image of C-COF-SO3H in Example 1;

[0044] Figure 6 This is a graph showing the N2 adsorption-desorption curves of C-COF-SO3H in Example 1;

[0045] Figure 7 This is a synthetic route diagram of COF-NH2 in Example 2;

[0046] Figure 8 The solid COF-NH2 in Example 2 13 C NMR

[0047] Figure 9 The XRD pattern of C-COF-NH2 in Example 2;

[0048] Figure 10 This is a graph showing the N2 adsorption-desorption curves of C-COF-NH2 in Example 2;

[0049] Figure 11 The NH3 adsorption capacity diagram of C-COF-SO3H in Example 1 is shown.

[0050] Figure 12 This is a graph showing the SO2 adsorption capacity of C-COF-NH2 in Example 2;

[0051] Figure 13 This is a graph showing the H2S adsorption capacity of C-COF-NH2 in Example 2. Detailed Implementation

[0052] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this application, and not all embodiments. The components of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0053] Traditional single activated carbon has drawbacks when adsorbing inorganic acid and alkali waste gases, including low upper limit of adsorption capacity, easy saturation, and an inability to simultaneously achieve optimal adsorption kinetics and selectivity. Furthermore, its removal efficiency significantly decreases under low-temperature and low-concentration conditions. While pure covalent organic framework (COF) crystal materials can achieve highly efficient adsorption, their expensive raw materials and slow mass transfer rates limit their large-scale application and economic viability. Therefore, existing technologies cannot simultaneously achieve high adsorption capacity, high selectivity, high mass transfer rate, and low-cost economic feasibility.

[0054] In response, this application proposes an activated carbon-supported COF composite adsorbent material. This material uses granular wood-based activated carbon with a multi-level pore structure and a specifically designed pore size distribution and specific surface area as a substrate, and loads specific covalent organic framework materials with sulfonic acid groups or amino functional groups on its surface and in its pores. At the same time, the loading mass ratio of the specific covalent organic framework materials is controlled, thereby achieving selective adsorption of inorganic acid and alkali waste gases.

[0055] In this application, the activated carbon-supported COF composite adsorbent material includes: a granular wood-based activated carbon substrate and a specific covalent organic framework material.

[0056] The granular wood-based activated carbon has a hierarchical porous structure, and the pore size distribution of the granular wood-based activated carbon substrate is 2~50 nm, with a specific surface area of ​​900~1200 m² / g. As a substrate material, this granular wood-based activated carbon, with its well-developed pore structure and large specific surface area, provides support for the loading of specific covalent organic framework materials and serves as a channel for gas mass transfer. The hierarchical porous structure facilitates the rapid diffusion and transport of gas molecules and provides abundant adsorption sites.

[0057] The specific covalent organic framework material is loaded onto the surface and within the pores of the granular wood-based activated carbon. The specific covalent organic framework material is a sulfonic acid-based covalent organic framework material with sulfonic acid functional groups or an amino-based covalent organic framework material with amino functional groups.

[0058] Specifically, the sulfonic acid groups in the sulfonic acid covalent organic framework material can act as Brønsted acidic sites to selectively adsorb alkaline gas molecules (such as ammonia); the amino functional groups in the amino covalent organic framework material can act as alkaline sites to selectively adsorb acidic gas molecules (such as sulfur dioxide and hydrogen sulfide).

[0059] In the activated carbon-supported COF composite adsorbent material, the mass of the specific covalent organic framework material is 0.01%-20% of the mass of the granular wood-based activated carbon. With this setting, a high density of specific functional groups can be introduced into the surface and pores of the activated carbon with a small amount of specific covalent organic framework material, forming chemical adsorption sites. At the same time, the specific covalent organic framework material is avoided from clogging the multi-level pores of the activated carbon, ensuring the advantage of high mass transfer rate.

[0060] Activated carbon-supported COF composite adsorbent materials effectively overcome the problems of low adsorption capacity and poor selectivity of traditional single activated carbon and high cost and slow mass transfer of pure COF materials by combining the well-developed pore structure of granular wood-based activated carbon with customized functional groups of specific covalent organic framework materials. This enables the composite material to achieve directional, efficient and selective adsorption of inorganic acid and alkali waste gases, while taking into account adsorption capacity, mass transfer rate and economic feasibility.

[0061] Please see Figure 1 The diagram illustrates a method for preparing an activated carbon-supported COF composite adsorbent material according to the present invention. The method includes:

[0062] Pretreatment of granular wood-based activated carbon:

[0063] Preparation of specific covalent organic framework materials: Based on the type of waste gas to be adsorbed, specific functional groups are selected, and specific covalent organic framework materials for selective adsorption of inorganic acid and alkali waste gases are prepared by reaction.

[0064] Loading of specific covalent organic framework material: The specific covalent organic framework material is prepared by means of a mass ratio of the dispersion to the granular wood-based activated carbon of (0.5~1.5):(8.5~9.5), thereby obtaining an initial activated carbon-supported COF composite adsorbent material; wherein the content of the specific covalent organic framework material is 0.01~20 wt%.

[0065] Post-processing of activated carbon-supported COF composite adsorbent material: The initial activated carbon-supported COF composite adsorbent material is dried to obtain the activated carbon-supported COF composite adsorbent material.

[0066] The following instruction manual will provide a detailed explanation of each step in the preparation method of activated carbon-supported COF composite adsorbent materials.

[0067] In this application, the pretreatment of granular wood-based activated carbon is configured to involve washing, acid washing, rinsing, and drying the granular wood-based activated carbon to remove impurities and unclog pores; specifically, the pretreatment of granular wood-based activated carbon is as follows:

[0068] Washing: Soak and stir the granular wood-based activated carbon in deionized water for 0.5 to 2 hours, and then rinse it with overflow until the effluent is clear. This setting can effectively remove physical impurities such as dust, loose particles, and water-soluble organic matter attached to the surface of the granular wood-based activated carbon.

[0069] Acid washing: Use 2~5wt% dilute hydrochloric acid, solid-liquid ratio 1:4~1:6, temperature 60~90℃, and soak and boil the granular wood-based activated carbon at a constant temperature for 1~3 hours. This setting can effectively remove inorganic salts, metal oxides and other mineral impurities adsorbed inside and on the surface of the granular wood-based activated carbon. Furthermore, these inorganic impurities can be dissolved or converted into soluble substances by reacting with dilute hydrochloric acid.

[0070] Rinsing: The granular wood-based activated carbon is rinsed with multi-stage pure water until the pH of the filtrate is between 6.5 and 7.5 and there is no chloride ion residue. This can thoroughly remove the acid and dissolution products remaining in the pores and surface of the granular wood-based activated carbon after acid washing, and avoid the adverse effects of acidic substances on the subsequent synthesis or stability of covalent organic framework materials.

[0071] Drying: The rinsed granular wood-based activated carbon is dried at a drying temperature of 80~100℃ for 4~8 hours to remove the moisture adsorbed inside and on the surface of the granular wood-based activated carbon, so that it reaches a dry state and provides a dry and stable substrate for subsequent impregnation and loading of specific covalent organic framework materials.

[0072] In this application, by pretreating the granular wood-based activated carbon, the purity, surface activity, and integrity of the pore structure of the granular wood-based activated carbon substrate are ensured, thereby significantly improving the loading efficiency and uniformity of specific covalent organic framework materials on activated carbon.

[0073] Furthermore, the specific covalent organic framework material described in this application includes a sulfonic acid-based covalent organic framework material for adsorbing alkaline waste gases and an amino-based covalent organic framework material for adsorbing acidic waste gases; the preparation of the specific covalent organic framework material is configured as follows: based on the type of waste gas to be adsorbed, specific functional groups are selected, and a specific covalent organic framework material for selectively adsorbing inorganic acid and alkaline waste gases is prepared by reaction.

[0074] In this application, the sulfonic acid-based covalent organic framework material used for alkaline waste gas adsorption is a polymer with a periodic pore structure formed by covalently linking organic monomers, and a sulfonic acid group (-SO3H) functional group is introduced into its framework. Specifically, the sulfonic acid group has strong acidity and can undergo acid-base neutralization reaction or form hydrogen bonds with alkaline substances, thereby achieving effective capture of alkaline waste gas. In this invention, the sulfonic acid group acts as a Brønsted acidic site, and its adsorption of ammonia molecules follows a synergistic mechanism combining chemical adsorption and physical enhancement. Specifically, the sulfonic acid group first releases a proton, and the ammonia molecule captures the proton with the lone pair electrons on its nitrogen atom, generating ammonium cations in situ, which then form ionic bonds with sulfonate anions, constituting a stable chemical adsorption host (primary force). On this basis, a high-density intermolecular hydrogen bond network (secondary force) is further formed between the oxygen atom in the sulfonate ion and the hydrogen atom of the NH bond in the ammonium ion. The hydrogen bond network significantly enhances the binding effect of the support on ammonium ions, thereby achieving efficient and stable capture of ammonia. For example, when treating alkaline waste gases such as ammonia (NH3), sulfonic acid groups can provide abundant active sites, which can fix ammonia molecules on the material surface or in the pores through protonation.

[0075] In a preferred embodiment of this application, the preparation of the sulfonic acid-based covalent organic framework material includes: reacting 2,5-diaminobenzene-1,4-disulfonic acid with trialdehyde phloroglucinol and flux in a molar ratio of 1:(1.3-1.4):(3-10); specifically, the molecular structure of 2,5-diaminobenzene-1,4-disulfonic acid contains two amino groups and two sulfonic acid groups. The amino groups are important reaction sites for forming the covalent organic framework structure and can undergo condensation reactions with aldehyde groups to construct stable covalent bonds; the sulfonic acid groups endow the obtained COF material with acidic functional groups, enabling it to selectively adsorb alkaline waste gas molecules through acid-base neutralization or hydrogen bonding.

[0076] The molecular structure of trialdehyde phloroglucinol contains three aldehyde groups. These aldehyde groups can undergo condensation reactions with the amino groups in 2,5-diaminobenzene-1,4-disulfonic acid to form imine bonds, thereby constructing a two-dimensional or three-dimensional periodic framework structure for COF materials.

[0077] The addition of flux can effectively lower the melting point of the reaction system, promote uniform mixing and full contact of reactants at high temperatures, and thus accelerate the reaction process.

[0078] In this embodiment, the molar ratio of reactant 2,5-diaminobenzene-1,4-disulfonic acid to trialdehyde phloroglucinol and flux is precisely controlled within the range of 1:(1.3-1.4):(3-10). This setting ensures that the two monomers can react fully in a near-stoichiometric ratio, while a slight excess of trialdehyde phloroglucinol (1.3-1.4 molar equivalents) helps to drive the reaction toward the formation of COF, ensuring the complete reaction of the amino group and thus forming a more complete framework structure. The molar ratio of flux (3-10 molar equivalents) ensures the smooth progress of the reaction while avoiding the adverse effects of excessive flux on product purity and subsequent separation and purification.

[0079] Furthermore, the amino covalent organic framework material used for adsorbing acidic waste gas is also a covalent organic polymer with a regular pore structure, and amino (-NH2) functional groups are introduced into its framework. The amino group is basic and can undergo acid-base neutralization reactions or form coordination bonds with acidic substances, thereby achieving selective adsorption of acidic waste gas. Moreover, in this application, the capture mechanism of acidic gas molecules by the amino functional group also follows the aforementioned synergistic enhancement pathway of ionic and hydrogen bonds, and this mechanism is universally applicable to sulfur dioxide and hydrogen sulfide. Specifically, as a Lewis basic site, the lone pair electrons carried by the nitrogen atom of the amino functional group endow this site with significant proton accepting ability.

[0080] Taking the treatment of acidic waste gases such as hydrogen sulfide or hydrogen chloride as an example, the amino functional group first binds to the acidic molecule through proton acceptance, forming a stable ionic bond anchor point (primary force). On this basis, a high-density intermolecular hydrogen bond network (secondary reinforcing force) is induced in situ between the electronegative atoms in the amino functional group and the polar hydrogen atoms in the acidic gas molecule. That is, the dual-effect mechanism of "ionic bond primary anchoring - hydrogen bond synergistic locking" provided in this invention is not unique to a single acidic molecule, but a common strengthening law of amino functional materials in the treatment of sulfur-containing and halogen-containing acidic waste gases, with the advantages of adsorption capacity and anti-desorption performance exceeding that of a single basic site.

[0081] In a preferred embodiment of this application, the preparation of the amino covalent organic framework material includes: reacting 2,5-bis((5-aminopentyl)oxy)-terephthalaldehyde with 1,3,6,8-tetra-(p-aminophenyl)pyrene and flux in a molar ratio of (2-4):(1-1.5):(4-12).

[0082] 2,5-bis((5-aminopentyl)oxy)terephthalaldehyde can provide aldehyde functional groups in the preparation of amino covalent organic framework materials, and can form a covalently linked framework structure through condensation reaction with amine monomers; furthermore, the long-chain aminopentyloxy group in the molecular structure of 2,5-bis((5-aminopentyl)oxy)terephthalaldehyde helps to increase the flexibility of the framework and may affect the pore size distribution and surface properties of the final material.

[0083] 1,3,6,8-Tetra-(p-aminophenyl)pyrene can provide multiple amino functional groups, which can then undergo condensation reactions with aldehyde monomers to form highly cross-linked two-dimensional or three-dimensional covalent organic framework structures; constructing stable, porous frameworks and endowing materials with good thermal stability and conjugation properties.

[0084] Similarly, fluxes are also used to lower the melting point of the reaction system, promote the uniform mixing and full reaction of reactants at high temperatures, and thus facilitate the crystallization growth and structure formation of covalent organic framework materials.

[0085] In this embodiment, 2,5-bis((5-aminopentyl)oxy)-terephthalaldehyde reacts with 1,3,6,8-tetra-(p-aminophenyl)pyrene and flux in a molar ratio of (2-4):(1-1.5):(4-12) to ensure that the monomers can polymerize efficiently to form a regular framework structure and avoid defects or unreacted monomer residues caused by monomer imbalance.

[0086] Furthermore, the preparation of the specific covalent organic framework material also includes a post-treatment of thermal activation after the preparation of the specific covalent organic framework material is completed. In this application, the post-treatment of thermal activation specifically refers to:

[0087] Immersion and washing: The specific covalent organic framework material is immersed and washed using an ethanol / water mixed solvent. Specifically, this step utilizes the different solubility properties of ethanol and water to efficiently dissolve and remove unreacted monomers, byproducts, and other soluble impurities remaining from the synthesis process, ensuring the purity of the specific covalent organic framework material.

[0088] Dehydration and drying: The specific covalent organic framework material after soaking and cleaning is dried at a drying temperature of 100±5℃ for 2h±10min to remove moisture from the specific covalent organic framework material; in this way, the moisture can be fully removed while avoiding damage to the structure of the covalent organic framework material by high temperature.

[0089] Thermal activation treatment: The specific covalent organic framework material is thermally activated in an inert atmosphere for 1-2 hours. Through thermal activation treatment, the pore structure of the covalent organic framework material can be optimized, its specific surface area and pore volume can be increased, and the crystallinity and thermal stability of the material can be enhanced. At the same time, thermal activation treatment in an inert atmosphere (such as nitrogen or argon) can effectively prevent the material from oxidizing or decomposing at high temperatures, thereby protecting its framework structure.

[0090] In this application, differential thermal activation treatment can be performed based on the type of specific covalent organic framework material. Specifically, when the specific covalent organic framework material is a sulfonic acid-based covalent organic framework material used for alkaline waste gas adsorption, the thermal activation temperature is 100~180℃. In fact, since sulfonic acid functional groups are relatively sensitive to heat, controlling the thermal activation temperature of the sulfonic acid-based covalent organic framework material at 100~180℃ can ensure that residual solvents, unreacted monomers and other impurities in the material are effectively removed while maximizing the protection of the structural integrity and activity of the sulfonic acid functional groups.

[0091] When the specific covalent organic framework material is an amino covalent organic framework material used for adsorption of acidic waste gas, the thermal activation temperature is 150~250℃. In fact, since amino functional groups usually have good thermal stability, setting the thermal activation temperature of the amino covalent organic framework material in the higher range of 150~250℃ can more thoroughly remove organic residues inside the material, promote further crystallization and optimization of the pore structure of the material, while ensuring that the amino functional groups are not damaged.

[0092] Furthermore, the specific loading of the covalent organic framework material is as follows:

[0093] Powder acquisition: The specific covalent organic framework material is ground and sieved into fine powder with a particle size of 50~100μm. In this process, grinding the specific covalent organic framework material can effectively reduce the original particle size of the specific covalent organic framework material, increase its specific surface area, and thus improve its dispersion rate in the dispersant. The sieving operation can ensure that the obtained fine powder of specific covalent organic framework material has a particle size of 50~100μm, so as to ensure that the specific covalent organic framework material can smoothly enter the multi-level pore structure of granular wood activated carbon and avoid clogging the pores due to excessive particle size.

[0094] Preparation of dispersion: The fine powder of the specific covalent organic framework material and the dispersant were mixed in a sand mill at a mass ratio of 5:95 and milled at a speed of 1500±10 r / min for 4±0.5 h to prepare the dispersion; wherein, the dispersant is a compound solution of organic solvent and water, and the proportion of water is 10~40%; this setting can ensure that the specific covalent organic framework material achieves a good dispersion state in the dispersant; the sand milling at a speed of 1500±10 r / min can provide sufficient shear force to break up any possible agglomerates, while avoiding excessive shear force from damaging the structure of the specific covalent organic framework material.

[0095] Furthermore, in this application, the dispersant is a compound solution of organic solvent and water, with the water ratio being 10-40%. This configuration effectively utilizes the synergistic effect of different solvents to optimize the wettability and dispersibility of the specific covalent organic framework material. Specifically, organic solvents typically have good ability to dissolve or disperse organic polymers, while the addition of water can adjust the polarity and surface tension of the solution. In this application, commonly used organic solvents may include styrene-maleic anhydride copolymer (SMA), polyvinylpyrrolidone (PVP), N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), tetrahydrofuran (THF), ethanol, or acetone, etc.

[0096] Furthermore, the pretreated granular wood-based activated carbon is impregnated in the dispersion by staged heating according to a temperature gradient of 30→50→70℃, stirring the pretreated granular wood-based activated carbon and the dispersion at a rotation speed of 100-300 r / min, and impregnating at a constant temperature for 0.5~24h. Specifically, during the impregnation process, the impregnation temperature is controlled to not reach the final temperature all at once, but to be gradually increased in stages. This allows the solvent in the specific covalent organic framework material dispersion to gradually penetrate into the micropores and mesopores of the activated carbon, while avoiding the specific covalent organic framework material from being deposited too quickly on the outer surface of the activated carbon due to excessively high temperature, thereby hindering its diffusion into the internal pores.

[0097] Meanwhile, stirring the pretreated granular wood-based activated carbon and the dispersion at a speed of 100-300 r / min ensures sufficient contact between the specific covalent organic framework material dispersion and the granular wood-based activated carbon, promoting uniform adsorption of the specific covalent organic framework material on the activated carbon surface and diffusion into the pores. In fact, in this application, a speed of 100-300 r / min is a moderately low speed range, which provides sufficient hybrid power to prevent the specific covalent organic framework material from settling or agglomerating, while avoiding wear of the activated carbon particles due to excessive stirring.

[0098] Implanting at a constant temperature for 0.5 to 24 hours provides sufficient time for the specific covalent organic framework material to undergo sufficient physical adsorption or chemical bonding with the activated carbon, ensuring that the specific covalent organic framework material can penetrate deeply into the pore structure of the activated carbon and be stably loaded.

[0099] The following description will provide a detailed explanation of the preparation method of the activated carbon-supported COF composite adsorbent material of this application through specific embodiments.

[0100] Example 1

[0101] This embodiment provides a C-COF-SO3H composite material formed by impregnating sulfonic acid-based COF with activated carbon.

[0102] The specific preparation method of C-COF-SO3H is as follows:

[0103] Pretreatment of granular wood-based activated carbon: The activated carbon was soaked and stirred in deionized water for 1 hour, overflowed and rinsed until there was no obvious turbidity, and then drained at room temperature for 2 hours; the activated carbon was soaked and boiled with 5wt% HCl at a solid-liquid ratio of 1:4 and a temperature of 70℃ for 3 hours; the acid solution was filtered and continuously washed with deionized water, drained, centrifuged and dehydrated, and repeatedly rinsed until the pH of the filtrate was 6.5–7.5; it was dried at 100℃ for 4 hours to obtain the base activated carbon material;

[0104] Preparation of specific covalent organic framework materials: Trialdehyde phloroglucinol, 2,5-diaminobenzene-1,4-disulfonic acid and acetic anhydride were added to a reaction vessel in a molar ratio of 1:1.4:2, and the temperature was controlled at 180℃ for 3 days. After the reaction, the product was soaked in ethanol for 48 hours, then soaked and washed in deionized water at 50℃ for 2 hours, dried at 100℃ for 2 hours, and then further activated at 180℃ for 2 hours to obtain the sulfonic acid group COF, named COF-SO3H.

[0105] Loading of specific covalent organic framework materials: COF-SO3H is ground and sieved to a fine powder of 50~100μm. COF-SO3H and dispersant solution are mixed in a sand mill at a mass ratio of 5:95. The mixture is stirred at a speed of 1500±10r / min for 4h to make the dispersant and COF-SO3H contact uniformly, and the sulfonic acid-based COF dispersion is obtained.

[0106] The pretreated activated carbon and COF dispersion were mixed evenly at a mass ratio of 9:1 and impregnated for 24 hours. The mixture was stirred at a speed of 200 r / min and a temperature of 40°C for 6 hours. The mixture was then washed with deionized water until no obvious turbidity was produced. The initial activated carbon-supported COF composite adsorbent material was thus prepared.

[0107] Post-treatment of activated carbon-supported COF composite adsorbent: drain at room temperature for 5 hours and dry at 100℃ for 4 hours to obtain C-COF-SO3H composite material.

[0108] Please see Figure 2 The diagram shown is a synthesis route diagram of COF-SO3H in this embodiment; Figure 3 This is the FT-IR image of COF-SO3H in this embodiment, where 1082 cm⁻¹ -1 With 1022cm -1 The newly added peak at this point indicates the presence of O=S=O in COF-SO3H, demonstrating the successful synthesis of COF-SO3H. Figure 4 The image shows the XRD pattern of C-COF-SO3H, which shows that C-COF-SO3H retains the crystallinity of COF-SO3H, proving that the C-COF-SO3H composite material was successfully impregnated. Figure 5 The image shows a STEM image of C-COF-SO3H. Since the activated carbon substrate does not contain sulfur, COF-SO3H contains sulfur, and C-COF-SO3H contains sulfur, this proves that the C-COF-SO3H composite material was successfully impregnated. Figure 6 The N2 adsorption-desorption curve of C-COF-SO3H is shown.

[0109] Example 2

[0110] This embodiment provides a C-COF-NH2 composite material formed by impregnating amino COF with activated carbon.

[0111] The specific preparation method of C-COF-NH2 is as follows:

[0112] Pretreatment of granular wood-based activated carbon: The activated carbon was soaked and stirred in deionized water for 1 hour, then overflowed and rinsed until no obvious turbidity was observed, and drained at room temperature for 2 hours; the activated carbon was soaked and boiled with 5wt% HCl at a solid-liquid ratio of 1:4 and a temperature of 70℃ for 3 hours; the acid solution was filtered and continuously washed with deionized water, drained, centrifuged and dehydrated, and repeatedly rinsed until the pH of the filtrate was 6.5–7.0; it was then dried at 100℃ for 4 hours to obtain the base activated carbon material;

[0113] Preparation of specific covalent organic framework material: 1,3,6,8-tetra-(p-aminophenyl)pyrene, 2,5-bis((5-aminopentyl)oxy)-terephthalaldehyde and benzoic acid were added to a reaction vessel in a molar ratio of 2:1:6. The temperature was controlled at 220℃ and the reaction time was 3 days. After the reaction, the product was soaked in ethanol for 48 h, then soaked and washed in deionized water at 50℃ for 2 h, dried at 100℃ for 2 h, and then further activated at 200℃ for 2 h to obtain the amino COF, named COF-NH2.

[0114] Loading of specific covalent organic framework material: COF-NH2 is ground and sieved to a fine powder of 50~100μm. The mass ratio of COF-NH2 to dispersant solution is 5:95. The mixture is stirred at 1500±10r / min for 4h to make the dispersant and COF-NH2 contact uniformly, and the aminoCOF dispersion is obtained.

[0115] The pretreated activated carbon and COF dispersion were mixed evenly at a mass ratio of 8.8-1.2 and impregnated for 18 hours. The mixture was stirred at 200 r / min and 40°C for 6 hours. The mixture was then washed with deionized water until no obvious turbidity was produced. The initial activated carbon-supported COF composite adsorbent material was thus prepared.

[0116] Post-treatment of activated carbon-supported COF composite adsorbent: drain at room temperature for 5 hours and dry at 100℃ for 4 hours to obtain C-COF-NH2 composite material.

[0117] Please see Figure 7 The diagram shown is a synthesis route for COF-NH2 in this embodiment. Figure 8 The image shows the solid-state 13C NMR spectrum of COF-NH2, where the characteristic peak at δ166 indicates the presence of -NH2, demonstrating the successful synthesis of COF-NH2. Figure 9 The image shows the XRD pattern of C-COF-NH2, which shows that C-COF-NH2 retains the crystallinity of COF-NH2, proving that the C-COF-NH2 composite material was successfully impregnated. Figure 10 The graph shows the N2 adsorption-desorption curves of C-COF-NH2.

[0118] As can be seen, the C-COF-SO3H composite material prepared in Example 1 has an adsorption capacity of 11.5 mmol / g for low-concentration NH3; the C-COF-NH2 composite material prepared in Example 2 has an adsorption capacity of 9.6 mmol / g for SO2 and 5.19 mmol / g for H2S. Both materials exhibit good renewability, and only a small amount of COF is required to achieve excellent adsorption effects. The cost is controllable, and the materials have good economic benefits.

[0119] Comparative Example 1

[0120] The difference between this comparative example and Example 1 is that COF was not added, and it was prepared under the same conditions using pure activated carbon.

[0121] Comparative Example 2

[0122] The difference between this comparative example and Example 1 lies in the pretreatment method of the granular wood-based activated carbon. Specifically, the preparation process of the C-COF-SO3H composite material in Comparative Example 2 is as follows:

[0123] Pretreatment of granular wood-based activated carbon: The activated carbon was soaked and stirred in deionized water for 1 hour, rinsed by overflow until there was no obvious turbidity, and then drained at room temperature for 2 hours; it was then dried at 100℃ for 4 hours to obtain the base activated carbon material.

[0124] Preparation of specific covalent organic framework materials: Trialdehyde phloroglucinol, 2,5-diaminobenzene-1,4-disulfonic acid and acetic anhydride were added to a reaction vessel in a molar ratio of 1:1.4:2, and the temperature was controlled at 180℃ for 3 days. After the reaction, the product was soaked in ethanol for 48 hours, then soaked and washed in deionized water at 50℃ for 2 hours, dried at 100℃ for 2 hours, and then further activated at 180℃ for 2 hours to obtain the sulfonic acid group COF, named COF-SO3H.

[0125] Loading of specific covalent organic framework materials: COF-SO3H is ground and sieved to a fine powder of 50~100μm. COF-SO3H and dispersant solution are mixed in a sand mill at a mass ratio of 5:95. The mixture is stirred at a speed of 1500±10r / min for 4h to ensure uniform contact between the dispersant and COF-SO3H, thereby obtaining the sulfonic acid-based COF dispersion.

[0126] The pretreated activated carbon and COF dispersion were mixed evenly at a mass ratio of 9:1 and impregnated for 24 hours. The mixture was stirred at a speed of 200 r / min and a temperature of 40°C for 6 hours. The mixture was then washed with deionized water until no obvious turbidity was produced. The initial activated carbon-supported COF composite adsorbent material was thus prepared.

[0127] Post-treatment of activated carbon-supported COF composite adsorbent: drain at room temperature for 5 hours and dry at 100℃ for 4 hours to obtain C-COF-SO3H composite material.

[0128] Comparative Example 3

[0129] Compared with Example 1, the preparation process of the activated carbon-supported COF composite adsorbent material in this comparative example differs in that the preparation process of the sulfonic acid-based COF is different, and the specific preparation method of C-COF-SO3H is as follows:

[0130] Pretreatment of granular wood-based activated carbon: The activated carbon was soaked and stirred in deionized water for 1 hour, overflowed and rinsed until there was no obvious turbidity, and then drained at room temperature for 2 hours; the activated carbon was soaked and boiled with 5wt% HCl at a solid-liquid ratio of 1:4 and a temperature of 70℃ for 3 hours; the acid solution was filtered and continuously washed with deionized water, drained, centrifuged and dehydrated, and repeatedly rinsed until the pH of the filtrate was 6.5–7.5; it was dried at 100℃ for 4 hours to obtain the base activated carbon material;

[0131] Preparation of a specific covalent organic framework material: Trialdehyde phloroglucinol, 2,5-diaminobenzenesulfonic acid, and acetic anhydride were added to a reaction vessel in a molar ratio of 1:1.4:2. The temperature was controlled at 180℃, and the reaction time was 3 days. After the reaction, the product was soaked in ethanol for 48 hours, washed with deionized water at 50℃ for 2 hours, dried at 100℃ for 2 hours, and then further activated at 180℃ for 2 hours to obtain the sulfonic acid COF, referred to as COF-SO3H.

[0132] Loading of specific covalent organic framework materials: COF-SO3H is ground and sieved to a fine powder of 50~100μm. COF-SO3H and dispersant solution are mixed in a sand mill at a mass ratio of 5:95. The mixture is stirred at a speed of 1500±10r / min for 4h to ensure uniform contact between the dispersant and COF-SO3H, thereby obtaining the sulfonic acid-based COF dispersion.

[0133] The pretreated activated carbon and COF dispersion were mixed evenly at a mass ratio of 9:1 and impregnated for 24 hours. The mixture was stirred at a speed of 200 r / min and a temperature of 40°C for 6 hours. The mixture was then washed with deionized water until no obvious turbidity was produced. The initial activated carbon-supported COF composite adsorbent material was thus prepared.

[0134] Post-treatment of activated carbon-supported COF composite adsorbent: drain at room temperature for 5 hours and dry at 100℃ for 4 hours to obtain C-COF-SO3H composite material.

[0135] Comparative Example 4

[0136] The difference between this comparative example and Example 1 lies in the feeding ratio of activated carbon to sulfonic acid-based COF dispersion during the loading process of the specific covalent organic framework material. The specific preparation method of the C-COF-SO3H composite material in Comparative Example 4 is as follows:

[0137] Pretreatment of granular wood-based activated carbon: The activated carbon was soaked and stirred in deionized water for 1 hour, overflowed and rinsed until there was no obvious turbidity, and then drained at room temperature for 2 hours; the activated carbon was soaked and boiled with 5wt% HCl at a solid-liquid ratio of 1:4 and a temperature of 70℃ for 3 hours; the acid solution was filtered and continuously washed with deionized water, drained, centrifuged and dehydrated, and repeatedly rinsed until the pH of the filtrate was 6.5–7.5; it was dried at 100℃ for 4 hours to obtain the base activated carbon material;

[0138] Preparation of specific covalent organic framework materials: Trialdehyde phloroglucinol, 2,5-diaminobenzene-1,4-disulfonic acid and acetic anhydride were added to a reaction vessel in a molar ratio of 1:1.4:2, and the temperature was controlled at 180℃ for 3 days. After the reaction, the product was soaked in ethanol for 48 hours, then soaked and washed in deionized water at 50℃ for 2 hours, dried at 100℃ for 2 hours, and then further activated at 180℃ for 2 hours to obtain the sulfonic acid group COF, named COF-SO3H.

[0139] Loading of specific covalent organic framework materials: COF-SO3H is ground and sieved to a fine powder of 50~100μm. COF-SO3H and dispersant solution are mixed in a sand mill at a mass ratio of 5:95. The mixture is stirred at a speed of 1500±10r / min for 4h to make the dispersant and COF-SO3H contact uniformly, and the sulfonic acid-based COF dispersion is obtained.

[0140] The pretreated activated carbon and COF dispersion were mixed evenly at a mass ratio of 9.5:5, impregnated for 24 hours, stirred at 200 r / min and controlled temperature of 40°C for 6 hours, and washed with deionized water until no obvious turbidity was produced; the initial activated carbon-supported COF composite adsorbent material was prepared.

[0141] Post-treatment of activated carbon-supported COF composite adsorbent: drain at room temperature for 5 hours and dry at 100℃ for 4 hours to obtain C-COF-SO3H composite material.

[0142] Comparative Example 5

[0143] The difference between this comparative example and Example 1 lies in the following: the ratio of activated carbon to sulfonic acid-based COF dispersion is different during the loading process of the specific covalent organic framework material; and the specific preparation method of C-COF-SO3H is as follows:

[0144] Pretreatment of granular wood-based activated carbon: The activated carbon was soaked and stirred in deionized water for 1 hour, overflowed and rinsed until there was no obvious turbidity, and then drained at room temperature for 2 hours; the activated carbon was soaked and boiled with 5wt% HCl at a solid-liquid ratio of 1:4 and a temperature of 70℃ for 3 hours; the acid solution was filtered and continuously washed with deionized water, drained, centrifuged and dehydrated, and repeatedly rinsed until the pH of the filtrate was 6.5–7.5; it was dried at 100℃ for 4 hours to obtain the base activated carbon material;

[0145] Preparation of specific covalent organic framework materials: Trialdehyde phloroglucinol, 2,5-diaminobenzene-1,4-disulfonic acid and acetic anhydride were added to a reaction vessel in a molar ratio of 1:1.4:2, and the temperature was controlled at 180℃ for 3 days. After the reaction, the product was soaked in ethanol for 48 hours, then soaked and washed in deionized water at 50℃ for 2 hours, dried at 100℃ for 2 hours, and then further activated at 180℃ for 2 hours to obtain the sulfonic acid group COF, named COF-SO3H.

[0146] Loading of specific covalent organic framework materials: COF-SO3H is ground and sieved to a fine powder of 50~100μm. COF-SO3H and dispersant solution are mixed in a sand mill at a mass ratio of 5:95. The mixture is stirred at a speed of 1500±10r / min for 4h to ensure uniform contact between the dispersant and COF-SO3H, thereby obtaining the sulfonic acid-based COF dispersion.

[0147] The pretreated activated carbon and COF dispersion were mixed evenly at a mass ratio of 9.2:0.8 and impregnated for 24 hours. The mixture was stirred at 200 r / min and 40°C for 6 hours. The mixture was then washed with deionized water until no obvious turbidity was produced. The initial activated carbon-supported COF composite adsorbent material was thus prepared.

[0148] Post-treatment of activated carbon-supported COF composite adsorbent: drain at room temperature for 5 hours and dry at 100℃ for 4 hours to obtain C-COF-SO3H composite material.

[0149] Comparative Example 6

[0150] The difference between this comparative example and Example 1 lies in the following: the ratio of activated carbon to sulfonic acid-based COF dispersion during the loading process of the specific covalent organic framework material is different, and the specific preparation method of C-COF-SO3H is as follows:

[0151] Pretreatment of granular wood-based activated carbon: The activated carbon was soaked and stirred in deionized water for 1 hour, overflowed and rinsed until there was no obvious turbidity, and then drained at room temperature for 2 hours; the activated carbon was soaked and boiled with 5wt% HCl at a solid-liquid ratio of 1:4 and a temperature of 70℃ for 3 hours; the acid solution was filtered and continuously washed with deionized water, drained, centrifuged and dehydrated, and repeatedly rinsed until the pH of the filtrate was 6.5–7.5; it was dried at 100℃ for 4 hours to obtain the base activated carbon material;

[0152] Preparation of specific covalent organic framework materials: Trialdehyde phloroglucinol, 2,5-diaminobenzene-1,4-disulfonic acid and acetic anhydride were added to a reaction vessel in a molar ratio of 1:1.4:2, and the temperature was controlled at 180℃ for 3 days. After the reaction, the product was soaked in ethanol for 48 hours, then soaked and washed in deionized water at 50℃ for 2 hours, dried at 100℃ for 2 hours, and then further activated at 180℃ for 2 hours to obtain the sulfonic acid group COF, named COF-SO3H.

[0153] Loading of specific covalent organic framework materials: COF-SO3H is ground and sieved to a fine powder of 50~100μm. COF-SO3H and dispersant solution are mixed in a sand mill at a mass ratio of 5:95. The mixture is stirred at a speed of 1500±10r / min for 4h to ensure uniform contact between the dispersant and COF-SO3H, thereby obtaining the sulfonic acid-based COF dispersion.

[0154] The pretreated activated carbon and COF dispersion were mixed evenly at a mass ratio of 8.5:1.5 and impregnated for 24 hours. The mixture was stirred at a speed of 200 r / min and a temperature of 40°C for 6 hours. The mixture was then washed with deionized water until no obvious turbidity was produced. The initial activated carbon-supported COF composite adsorbent material was thus prepared.

[0155] Post-treatment of activated carbon-supported COF composite adsorbent: drain at room temperature for 5 hours and dry at 100℃ for 4 hours to obtain C-COF-SO3H composite material.

[0156] Comparative Example 7

[0157] The difference between this comparative example and Example 2 is that COF was not added, and the preparation was carried out under the same conditions with pure activated carbon.

[0158] Comparative Example 8

[0159] The difference between this comparative example and Example 2 lies in the pretreatment method of the granular wood-based activated carbon. Specifically, the preparation method of C-COF-NH2 in this comparative example is as follows:

[0160] Pretreatment of granular wood-based activated carbon: The activated carbon was soaked and stirred in deionized water for 1 hour, overflowed and rinsed until no obvious turbidity was observed, and then drained at room temperature for 2 hours; dried at 100℃ for 4 hours; the activated carbon was soaked and boiled with 5wt% HCl at a solid-liquid ratio of 1:4 and a temperature of 70℃ for 3 hours; the acid solution was filtered and continuously washed with deionized water, drained, centrifuged and dehydrated, and repeatedly rinsed until the pH of the filtrate was 6.5–7.0; dried at 100℃ for 4 hours to obtain the base activated carbon material;

[0161] Preparation of a specific covalent organic framework material: 1,3,6,8-tetra-(p-aminophenyl)pyrene, 2,5-((5-aminopentyl)oxy)terephthalaldehyde, and benzoic acid were added to a reaction vessel in a molar ratio of 2:1:6. The temperature was controlled at 220℃, and the reaction time was 3 days. After the reaction, the product was soaked in ethanol for 48 hours, then soaked and washed in deionized water at 50℃ for 2 hours, dried at 100℃ for 2 hours, and then further activated at 200℃ for 2 hours to obtain the amino COF, referred to as COF-NH2;

[0162] Loading of specific covalent organic framework materials: COF is ground and sieved to a fine powder of 50~100μm. COF and dispersant solution are mixed in a sand mill at a mass ratio of 5:95. The mixture is stirred at a speed of 1500±10r / min for 4h to make the dispersant and COF contact uniformly, and the aminoCOF dispersion is obtained.

[0163] The pretreated activated carbon and COF dispersion were mixed evenly at a mass ratio of 8.8:1.2 and impregnated for 18 hours. The mixture was stirred at 200 r / min and 40°C for 6 hours. The mixture was then washed with deionized water until no obvious turbidity was produced. The initial activated carbon-supported COF composite adsorbent material was thus prepared.

[0164] Post-treatment of activated carbon-supported COF composite adsorbent: drain at room temperature for 5 hours and dry at 100℃ for 4 hours to obtain C-COF-NH2 composite material.

[0165] Comparative Example 9

[0166] The difference between this comparative example and Example 2 lies in the preparation method of the specific covalent organic framework material. Specifically, the preparation method of C-COF-NH2 in this comparative example is as follows:

[0167] Pretreatment of granular wood-based activated carbon: The activated carbon was soaked and stirred in deionized water for 1 hour, then overflowed and rinsed until no obvious turbidity was observed, and drained at room temperature for 2 hours; the activated carbon was soaked and boiled with 5wt% HCl at a solid-liquid ratio of 1:4 and a temperature of 70℃ for 3 hours; the acid solution was filtered and continuously washed with deionized water, drained, centrifuged and dehydrated, and repeatedly rinsed until the pH of the filtrate was 6.5–7.0; it was then dried at 100℃ for 4 hours to obtain the base activated carbon material;

[0168] Preparation of a specific covalent organic framework material: 1,3,6,8-tetra-(p-aminophenyl)pyrene, 2,5-((5-aminopentyl)oxy)terephthalaldehyde, and benzoic acid were added to a reaction vessel in a molar ratio of 2:1:6. The temperature was controlled at 220℃, and the reaction time was 3 days. After the reaction, the product was soaked in ethanol for 48 hours, then soaked and washed in deionized water at 50℃ for 2 hours, dried at 100℃ for 2 hours, and then further activated at 200℃ for 2 hours to obtain the amino COF, referred to as COF-NH2;

[0169] Loading of specific covalent organic framework materials: COF is ground and sieved to a fine powder of 50~100μm. COF and dispersant solution are mixed in a sand mill at a mass ratio of 5:95. The mixture is stirred at a speed of 1500±10r / min for 4h to make the dispersant and COF contact uniformly, and the aminoCOF dispersion is obtained.

[0170] The pretreated activated carbon and COF dispersion were mixed evenly at a mass ratio of 8.8:1.2 and impregnated for 18 hours. The mixture was stirred at 200 r / min and 40°C for 6 hours. The mixture was then washed with deionized water until no obvious turbidity was produced. The initial activated carbon-supported COF composite adsorbent material was thus prepared.

[0171] Post-treatment of activated carbon-supported COF composite adsorbent: drain at room temperature for 5 hours and dry at 100℃ for 4 hours to obtain C-COF-NH2 composite material.

[0172] Comparative Example 10

[0173] The difference between this comparative example and Example 2 lies in the following: the feeding ratio of activated carbon to amino-COF dispersion is different during the loading process of the specific covalent organic framework material; and the specific preparation method of C-COF-NH2 is as follows:

[0174] Pretreatment of granular wood-based activated carbon: The activated carbon was soaked and stirred in deionized water for 1 hour, then overflowed and rinsed until no obvious turbidity was observed, and drained at room temperature for 2 hours; the activated carbon was soaked and boiled with 5wt% HCl at a solid-liquid ratio of 1:4 and a temperature of 70℃ for 3 hours; the acid solution was filtered and continuously washed with deionized water, drained, centrifuged and dehydrated, and repeatedly rinsed until the pH of the filtrate was 6.5–7.0; it was then dried at 100℃ for 4 hours to obtain the base activated carbon material;

[0175] Preparation of specific covalent organic framework material: 1,3,6,8-tetra-(p-aminophenyl)pyrene, 2,5-bis((5-aminopentyl)oxy)-terephthalaldehyde and benzoic acid were added to a reaction vessel in a molar ratio of 2:1:6. The temperature was controlled at 220℃ and the reaction time was 3 days. After the reaction, the product was soaked in ethanol for 48 h, then soaked and washed in deionized water at 50℃ for 2 h, dried at 100℃ for 2 h, and then further activated at 200℃ for 2 h to obtain the amino COF, named COF-NH2.

[0176] Loading of specific covalent organic framework materials: COF is ground and sieved to a fine powder of 50~100μm. COF and dispersant solution are mixed in a sand mill at a mass ratio of 5:95. The mixture is stirred at a speed of 1500±10r / min for 4h to make the dispersant and COF contact uniformly, and the aminoCOF dispersion is obtained.

[0177] The pretreated activated carbon and COF dispersion were mixed evenly at a mass ratio of 9.2:8, impregnated for 18 hours, stirred at 200 r / min and 40°C for 6 hours, and washed with deionized water until no obvious turbidity was produced; the initial activated carbon-supported COF composite adsorbent material was prepared.

[0178] Post-treatment of activated carbon-supported COF composite adsorbent: drain at room temperature for 5 hours and dry at 100℃ for 4 hours to obtain C-COF-NH2 composite material.

[0179] Comparative Example 11

[0180] The difference between this comparative example and Example 2 lies in the following: the feeding ratio of activated carbon to amino-COF dispersion is different during the loading process of the specific covalent organic framework material; and the specific preparation method of C-COF-NH2 is as follows:

[0181] Pretreatment of granular wood-based activated carbon: The activated carbon was soaked and stirred in deionized water for 1 hour, then overflowed and rinsed until no obvious turbidity was observed, and drained at room temperature for 2 hours; the activated carbon was soaked and boiled with 5wt% HCl at a solid-liquid ratio of 1:4 and a temperature of 70℃ for 3 hours; the acid solution was filtered and continuously washed with deionized water, drained, centrifuged and dehydrated, and repeatedly rinsed until the pH of the filtrate was 6.5–7.0; it was then dried at 100℃ for 4 hours to obtain the base activated carbon material;

[0182] Preparation of specific covalent organic framework material: 1,3,6,8-tetra-(p-aminophenyl)pyrene, 2,5-bis((5-aminopentyl)oxy)-terephthalaldehyde and benzoic acid were added to a reaction vessel in a molar ratio of 2:1:6. The temperature was controlled at 220℃ and the reaction time was 3 days. After the reaction, the product was soaked in ethanol for 48 h, then soaked and washed in deionized water at 50℃ for 2 h, dried at 100℃ for 2 h, and then further activated at 200℃ for 2 h to obtain the amino COF, named COF-NH2.

[0183] Loading of specific covalent organic framework materials: COF is ground and sieved to a fine powder of 50~100μm. COF and dispersant solution are mixed in a sand mill at a mass ratio of 5:95. The mixture is stirred at a speed of 1500±10r / min for 4h to make the dispersant and COF contact uniformly, and the aminoCOF dispersion is obtained.

[0184] The pretreated activated carbon and COF dispersion were mixed evenly at a mass ratio of 9:1 and impregnated for 18 hours. The mixture was stirred at a speed of 200 r / min and a temperature of 40°C for 6 hours. The mixture was then washed with deionized water until no obvious turbidity was produced. The initial activated carbon-supported COF composite adsorbent material was thus prepared.

[0185] Post-treatment of activated carbon-supported COF composite adsorbent: air-dry at room temperature for 5 hours, then dry at 100℃ for 4 hours to obtain the C-COF-NH2 composite material.

[0186] Comparative Example 12

[0187] The difference between this comparative example and Example 2 lies in the following: the feeding ratio of activated carbon to amino-COF dispersion is different during the loading process of the specific covalent organic framework material; and the specific preparation method of C-COF-NH2 is as follows:

[0188] Pretreatment of granular wood-based activated carbon: The activated carbon was soaked and stirred in deionized water for 1 hour, then overflowed and rinsed until no obvious turbidity was observed, and drained at room temperature for 2 hours; the activated carbon was soaked and boiled with 5wt% HCl at a solid-liquid ratio of 1:4 and a temperature of 70℃ for 3 hours; the acid solution was filtered and continuously washed with deionized water, drained, centrifuged and dehydrated, and repeatedly rinsed until the pH of the filtrate was 6.5–7.0; it was then dried at 100℃ for 4 hours to obtain the base activated carbon material;

[0189] Preparation of specific covalent organic framework material: 1,3,6,8-tetra-(p-aminophenyl)pyrene, 2,5-bis((5-aminopentyl)oxy)-terephthalaldehyde and benzoic acid were added to a reaction vessel in a molar ratio of 2:1:6. The temperature was controlled at 220℃ and the reaction time was 3 days. After the reaction, the product was soaked in ethanol for 48 h, then soaked and washed in deionized water at 50℃ for 2 h, dried at 100℃ for 2 h, and then further activated at 200℃ for 2 h to obtain the amino COF, named COF-NH2.

[0190] Loading of specific covalent organic framework materials: COF is ground and sieved to a fine powder of 50~100μm. COF and dispersant solution are mixed in a sand mill at a mass ratio of 5:95. The mixture is stirred at a speed of 1500±10r / min for 4h to make the dispersant and COF contact uniformly, and the aminoCOF dispersion is obtained.

[0191] The pretreated activated carbon and COF dispersion were mixed evenly at a mass ratio of 8.5:1.5, impregnated for 18 hours, stirred at 200 r / min and 40°C for 6 hours, and washed with deionized water until no obvious turbidity was produced; the initial activated carbon-supported COF composite adsorbent material was prepared.

[0192] Post-treatment of activated carbon-supported COF composite adsorbent: drain at room temperature for 5 hours and dry at 100℃ for 4 hours to obtain C-COF-NH2 composite material.

[0193] The composite materials prepared in Example 1 and Comparative Examples 1-6 were characterized for performance parameters and subjected to dynamic adsorption tests of ammonia gas: the composite materials were subjected to ammonia adsorption tests using a VOC adsorption device, with a gas flow rate of 8 L / min, a test concentration of 20 ppm, a test temperature of room temperature of 25 ± 5°C, and a test pressure of 1 bar. The test results are shown in Table 1.

[0194] Table 1. Ammonia adsorption test of composite materials using VOC adsorption device.

[0195]

[0196] As shown in Table 1, the C-COF-SO3H composite material obtained by the method in Example 1 exhibits excellent adsorption performance for ammonia, with a maximum adsorption capacity of 11.5 mmol / g. Furthermore, since Comparative Example 1 did not include COF, the adsorption effect was significantly reduced, indicating that the activated carbon itself has limited adsorption capacity. In Comparative Example 2, the activated carbon was not pretreated with acid washing, and some impurities still occupied the pores, resulting in a moderate free pore volume and porosity of the composite material. Acid washing significantly enhanced the adsorption performance, demonstrating the necessity of acid washing as a pretreatment for activated carbon. In Comparative Example 3, the density of -SO3H functional groups was lower than in Example 1, leading to a decrease in performance, indicating that the increased density of -SO3H groups increased the number of adsorption sites, which is beneficial for adsorption. In Comparative Examples 4-6, with the increase of the feed mass ratio, COF both occupied part of the activated carbon pores, reducing porosity, and contributed to the pore environment, improving BET. The adsorption capacity first increased and then decreased, with a 9:1 feed ratio showing the best effect.

[0197] The composite materials prepared in Example 2 and Comparative Examples 7-12 were characterized for performance parameters and subjected to dynamic adsorption tests of sulfur dioxide and hydrogen sulfide gases. The composite materials were tested for sulfur dioxide and hydrogen sulfide adsorption using a VOC adsorption device. The gas flow rate was 5 L / min, the test concentration was 10 ppm, the test temperature was room temperature 25 ± 5°C, and the test pressure was 1 bar. The test results are shown in Table 2.

[0198] Table 2. Adsorption tests of sulfur dioxide and hydrogen sulfide on composite materials using VOC adsorption devices.

[0199]

[0200] As can be seen from Table 2, the C-COF-NH2 composite material obtained by the method in Example 2 has excellent adsorption performance for sulfur dioxide and hydrogen sulfide, with maximum adsorption capacities of 9.6 mmol / g and 5.19 mmol / g, respectively.

[0201] Furthermore, since COF was not added in Comparative Example 7, the adsorption effect was significantly reduced, indicating that the adsorption performance of activated carbon itself is limited. In Comparative Example 8, the activated carbon was not pretreated with acid washing, and some impurities still occupied the pores, resulting in the free pore volume and porosity of the composite material being at a moderate level. After acid washing, the adsorption performance was significantly enhanced, indicating the necessity of acid washing as a pretreatment for activated carbon. In Comparative Example 9, the density of -NH2 functional groups was lower than that in Example 1, and the performance decreased, indicating that the increased density of -NH2 groups increased the adsorption sites, which is beneficial to adsorption. In Comparative Examples 4-6, as the mass ratio of feed increased, COF both occupied part of the pores of activated carbon, reducing porosity, and contributed part of the pore environment to improve BET. The adsorption amount first increased and then decreased, and the effect was best at a feed ratio of 8.8:1.2.

[0202] Stability test: The adsorbents obtained in Examples 1 and 2 after the adsorption performance test were purged with hot nitrogen at 120°C for 1-2 hours, and then the next test was performed. This cycle was repeated 5 times.

[0203] For further details, please refer to [link / reference]. Figure 11 The figure shows the NH3 adsorption capacity of the C-COF-SO3H adsorbent prepared in Example 1 after 5 cycles at room temperature (298 K) and 1 Bar. It can be seen that after 5 adsorption cycles, the NH3 adsorption capacity of the adsorbent remains at more than 92% of the initial capacity, indicating that the adsorbent obtained by the present invention has excellent adsorption stability.

[0204] Please see Figure 12 The figure shows the SO2 adsorption capacity of the C-COF-NH2 adsorbent prepared in Example 2 after 5 cycles at room temperature (298 K) and 1 Bar. It can be seen that after 5 adsorption cycles, the SO2 adsorption capacity of the adsorbent remains at more than 90% of the initial capacity, indicating that the adsorbent obtained by the present invention has excellent adsorption stability.

[0205] Please see Figure 13 The figure shows the H2S adsorption capacity of the C-COF-NH2 adsorbent prepared in Example 2 after 5 cycles at room temperature (298 K) and 1 Bar. It can be seen that after 5 adsorption cycles, the H2S adsorption capacity of the adsorbent remains at more than 94.2% of the initial capacity, indicating that the adsorbent obtained by the present invention has excellent adsorption stability.

[0206] In summary, this invention combines specific covalent organic framework materials with activated carbon to prepare C-COF-SO3H composite materials and C-COF-NH2 composite materials. These activated carbon composite materials inherit the advantages of COF, such as large surface area and high porosity, while the high density of sulfonic acid groups or amino functional groups enhances the adsorption of alkaline or acidic gases. In fact, the adsorption capacity of purely alkaline or acidic gases on activated carbon is mainly determined by the narrow micropore volume and functional groups of the material. Introducing a high density of sulfonic acid groups or amino functional groups allows the sulfonic acid groups to act as Brønsted acidic sites, coordinating with electron pairs of NH3, which is beneficial for enhancing the NH3 adsorption capacity of the material. Similarly, the amino functional groups act as Lewis basic sites, coordinating with electron pairs of SO2 and H2S, which is beneficial for enhancing the SO2 and H2S adsorption capacity of the material. This invention provides a new solution for the removal of low-concentration VOCs.

[0207] Meanwhile, unlike existing technologies that modify porous materials such as activated carbon by impregnation with acid / alkaline reagents to achieve one-time, non-cyclic adsorption, the activated carbon-supported COF composite adsorbent material of this application, with its excellent chemical stability and structural integrity endowed by its covalent organic framework, effectively maintains the adsorption sites during multiple adsorption-desorption cycles, thus giving the activated carbon-supported COF composite adsorbent material a long service life and long cycle life; meeting the practical needs of industrial waste gas treatment and household air purification for the economy and sustainability of adsorbents.

[0208] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the technical solutions of the embodiments of the present invention.

Claims

1. An activated carbon-supported COF composite adsorbent material for the selective adsorption of inorganic acid and alkali waste gases, characterized in that, include: Granular wood-based activated carbon substrate: The granular wood-based activated carbon has a multi-level pore structure, and the pore size distribution of the granular wood-based activated carbon substrate is 2~50nm, and the specific surface area is 900~1200m² / g. Specific covalent organic framework material: loaded on the surface and within the pores of the granular wood-based activated carbon; the specific covalent organic framework material is a sulfonic acid group covalent organic framework material with sulfonic acid functional groups or an amino group covalent organic framework material with amino functional groups. In the activated carbon-supported COF composite adsorbent material, the mass content of the specific covalent organic framework material is 0.01%-20%.

2. A method for preparing an activated carbon-supported COF composite adsorbent, characterized in that, include: Pretreatment of granular wood-based activated carbon: Preparation of specific covalent organic framework materials: Based on the type of waste gas to be adsorbed, specific functional groups are selected, and specific covalent organic framework materials for selective adsorption of inorganic acid and alkali waste gases are prepared by reaction. Loading of specific covalent organic framework material: A dispersion of the specific covalent organic framework material is prepared by impregnating pretreated granular wood-based activated carbon in the dispersion; wherein the mass ratio of the dispersion to the granular wood-based activated carbon is (0.5~1.5):(8.5~9.5), thus obtaining an initial activated carbon-loaded COF composite adsorbent; wherein the content of the specific covalent organic framework material is 0.01~20wt%; Post-processing of activated carbon-supported COF composite adsorbent material: The initial activated carbon-supported COF composite adsorbent material is dried to obtain the activated carbon-supported COF composite adsorbent material.

3. The method for preparing activated carbon-supported COF composite adsorbent material according to claim 2, characterized in that, The pretreatment of the granular wood-based activated carbon specifically involves: Washing: Soak the granular wood-based activated carbon in deionized water and stir for 0.5 to 2 hours, then overflow and rinse until the effluent is clear; Acid washing: Use 2~5wt% dilute hydrochloric acid, solid-liquid ratio 1:4~1:6, temperature 60~90℃, and soak and cook the granular wood-based activated carbon after water washing at a constant temperature for 1~3 hours. Rinsing: The granular wood-based activated carbon is rinsed with multi-stage pure water until the pH of the filtrate is between 6.5 and 7.5 and there is no chloride ion residue. Drying: The rinsed granular wood-based activated carbon is dried at a drying temperature of 80~100℃ for 4~8 hours.

4. The method for preparing activated carbon-supported COF composite adsorbent material according to claim 2, characterized in that, The specific covalent organic framework materials include sulfonic acid-based covalent organic framework materials for adsorbing alkaline waste gases and amino covalent organic framework materials for adsorbing acidic waste gases.

5. The method for preparing activated carbon-supported COF composite adsorbent material according to claim 4, characterized in that, The preparation of the sulfonic acid-based covalent organic framework material includes reacting 2,5-diaminobenzene-1,4-disulfonic acid with trialdehyde-resorcinol and flux in a molar ratio of 1:(1.3-1.4):(3-10).

6. The method for preparing activated carbon-supported COF composite adsorbent material according to claim 4, characterized in that, The preparation of the amino covalent organic framework material includes reacting 2,5-bis((5-aminopentyl)oxy)terephthalaldehyde with 1,3,6,8-tetra-(p-aminophenyl)pyrene and flux in a molar ratio of (2-4):(1-1.5):(4-12).

7. The method for preparing activated carbon-supported COF composite adsorbent material according to claim 2, characterized in that, After the preparation of the specific covalent organic framework material is completed, the method further includes a thermal activation post-treatment of the specific covalent organic framework material, wherein the thermal activation post-treatment specifically includes: Immersion washing: The specific covalent organic framework material was immersed and washed using an ethanol / water mixed solvent; Dehydration and drying: The specific covalent organic framework material after soaking and cleaning is dried at a drying temperature of 100±5℃ for 2h±10min to remove moisture from the specific covalent organic framework material; Thermal activation treatment: The specific covalent organic framework material is thermally activated in an inert atmosphere for 1-2 hours.

8. The method for preparing activated carbon-supported COF composite adsorbent material according to claim 7, characterized in that, During the heat activation process: When the specific covalent organic framework material is a sulfonic acid-based covalent organic framework material used for alkaline waste gas adsorption, the thermal activation temperature is 100~180℃. When the specific covalent organic framework material is an amino-covalent organic framework material used for adsorption of acidic waste gas, the thermal activation temperature is 150~250℃.

9. The method for preparing activated carbon-supported COF composite adsorbent material according to claim 2, characterized in that, The specific loading of the specific covalent organic framework material is as follows: Obtaining the powder: The specific covalent organic framework material is ground and sieved to a fine powder with a particle size of 50-100 μm; Preparation of dispersion: The fine powder of the specific covalent organic framework material and the dispersant are mixed in a sand mill at a mass ratio of 5:95 and milled at a speed of 1500±10 r / min for 4±0.5 h to prepare the dispersion; wherein the dispersant is a compound solution of organic solvent and water, and the proportion of water is 10~40%.

10. The method for preparing activated carbon-supported COF composite adsorbent material according to claim 2, characterized in that, During the loading process of the specific covalent organic framework material, the pretreated granular wood-based activated carbon is impregnated in the dispersion by segmented heating according to a temperature gradient of 30→50→70℃, stirring the pretreated granular wood-based activated carbon and the dispersion at a rotation speed of 100-300r / min, and impregnating at a constant temperature for 0.5-24h.

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