A β-COF / GA composite adsorbent material, its preparation method and application

Abstract

This invention relates to a β -COF / GA composite adsorbent materials use graphene oxide as a carbon precursor and a reinforcing phase. β -COF blends form an aqueous solution system, and ammonium citrate is added as a reducing agent to carry out a liquid-phase reduction self-assembly reaction. β -COF loading on the surface and pores of reduced graphene aerogel β An adsorbent material with a COF to graphene oxide mass ratio of 1:5 to 15. This invention... β The COF / GA composite adsorbent material has a rich microporous structure and high adsorption activity, and can be used for the efficient adsorption and removal of phenol molecules in aqueous solutions.

Description

Technical Field

[0001] This invention belongs to the field of water treatment adsorption material technology, and relates to an adsorption material for adsorbing and removing phenol from wastewater, particularly a composite adsorption material based on carbon aerogel. Background Technology

[0002] Industrial wastewater contains a large amount of organic pollutants, with phenol molecules making up a significant proportion. Phenol and its derivatives are carcinogenic and mutagenic to animals and humans, and the discharge of phenol-containing wastewater poses a significant threat to human health and environmental quality. Researching and achieving the adsorption and removal of organic pollutants, represented by phenol, from industrial wastewater is of great significance for wastewater treatment, pollutant reduction, and ecological environmental protection.

[0003] Graphene aerogel, as a bulk carbon material with a hierarchical porous structure and excellent mechanical and physicochemical stability, not only possesses the advantages of carbon-based adsorbents such as low density, high strength, environmental friendliness, controllable structure, and surface modification, but also exhibits advantages such as rapid mass transfer, high solid-liquid separation efficiency, minimal secondary pollution to the liquid phase environment, and good regenerability. Therefore, it has become a highly promising adsorbent material in the field of phenol removal from industrial wastewater. However, single-component graphene aerogel adsorbents have low micropore content and a limited variety and quantity of surface active functional groups, resulting in a low adsorption capacity for phenol.

[0004] By employing a method with high aqueous phase stability, high micropore content, and high activity β - Ketoenamine covalent organic framework materials ( β -COF) is combined with graphene aerogel to improve the micropore content and adsorption activity of the adsorbent material, and to construct... β -COF / graphene composite aerogel bulk adsorption material ( β (-COF / GA) has good research and development value for improving the adsorption capacity of graphene aerogel-based adsorbents for phenol and promoting the practical application of phenol removal in industrial wastewater. Summary of the Invention

[0005] The purpose of this invention is to provide a β -COF / GA composite adsorbent material and its preparation method are used to effectively improve the phenol adsorption capacity of graphene aerogel-based adsorbents.

[0006] To achieve the above-mentioned objectives, the present invention... β -COF / GA composite adsorbent materials use graphene oxide as a carbon precursor and a reinforcing phase. β -COF blends form an aqueous solution system, and ammonium citrate is added as a reducing agent to carry out a liquid-phase reduction self-assembly reaction.β -COF loading was obtained on the surface and in the pores of the reduced graphene aerogel. β -An adsorbent material with a COF to graphene oxide mass ratio of 1:5 to 15.

[0007] The present invention β -COF / GA composite adsorbent material uses graphene oxide as a carbon precursor. On the one hand, graphene oxide can self-assemble and connect through hydrothermal reduction reaction to form a three-dimensional bulk graphene aerogel with ideal pore structure and mechanical properties. On the other hand, since graphene oxide is a large-sized two-dimensional structure and contains abundant oxygen-containing functional groups, the graphene aerogel obtained with it as a precursor can easily form π-π interactions and hydrogen bonds with phenol, which can improve its adsorption activity and adsorption capacity for phenol.

[0008] The present invention β -Reinforcing phase in COF / GA composite adsorbent materials β -COF is a covalent organic framework material with high aqueous stability, abundant micropores, and rich nitrogen and oxygen functional groups. It can interact and attract phenol, allowing appropriate amounts of... β -COF loaded on the surface and pore structure of graphene aerogel can effectively improve the overall micropore content and adsorption activity of the adsorption material.

[0009] This invention uses an appropriate amount β -COF was blended with graphene oxide in an aqueous solution, and ammonium citrate was added as a reducing agent to carry out a liquid-phase self-assembly reaction, achieving an appropriate amount of... β Loading α-COF onto the surface and pore structure of graphene aerogel yielded bulk materials with abundant microporous structure and high adsorption activity. β -COF / GA composite adsorbent material can be used for the efficient adsorption and removal of phenol molecules in aqueous solutions.

[0010] Furthermore, the present invention also provides a suitable method for the aforementioned β Preparation method of COF / GA composite adsorbent material:

[0011] 1) Using 1,3,5-tricarboxymethyl phloroglucinol and aniline compounds as reactants, water as solvent, and p-toluenesulfonic acid added to promote the dissolution of the reactants in water, a hydrothermal reaction is carried out to link the reactants into six-membered ring structural units, resulting in a water-stable powder. β -COF;

[0012] 2) with β -COF is the reinforcing phase, graphene oxide is the carbon precursor, and ammonium citrate is the reducing agent. They are mixed and dissolved in water to undergo a liquid-phase reduction self-assembly reaction, reducing graphene oxide and inducing self-assembly behavior. β-COF loading forms on the graphene surface and in the pores. β -COF / graphene composite hydrogel, obtained by freeze-drying β -COF / GA composite adsorbent material.

[0013] The aniline compound may be p-phenylenediamine or benzidine.

[0014] Specifically, the preferred molar ratio of 1,3,5-tricarboxymethyl phloroglucinol to aniline compounds is 1:1 to 2, and the preferred molar ratio of 1,3,5-tricarboxymethyl phloroglucinol to p-toluenesulfonic acid is 1:1 to 2.

[0015] Furthermore, the hydrothermal reaction is specifically carried out at a constant temperature of 100–150°C for 18–36 hours.

[0016] Specifically, preferred β The mass ratio of COF to graphene oxide is 1:5 to 15, and the mass ratio of graphene oxide to ammonium citrate is 1:3 to 7.

[0017] Furthermore, the liquid-phase reduction self-assembly reaction is specifically carried out at a constant temperature of 100–150°C for 8–15 hours using hydrothermal reaction.

[0018] Furthermore, specifically... β The COF / graphene composite hydrogel was frozen at -80°C to solidify the water, and then freeze-dried to sublimate the solid water, thus obtaining the product described in this invention. β -COF / GA composite adsorbent material.

[0019] This invention utilizes high aqueous phase stability, high micropore content, and high activity. β -COF, as a reinforcing phase, improves the problems of low micropore content and low adsorption activity in existing graphene aerogel adsorption materials.

[0020] The present invention prepared β -The COF / GA composite adsorbent material is a black cylindrical block adsorbent material, internally composed of interconnected graphene sheets. Appropriate amounts of [unspecified substance] are loaded on the graphene sheets and in the stacked channels. β -COF nanoparticles, with their rich microporous structure and high adsorption activity, can achieve efficient adsorption and removal of phenol molecules in aqueous phase and can be reused multiple times after elution and regeneration.

[0021] This invention β -COF / GA composite adsorbent materials are simple to prepare, low in cost, easy to use and operate, and highly practical. They can be widely used in adsorption, separation, detection and other fields. Attached Figure Description

[0022] Figure 1 It is the product of Example 1.β -COF(a) and β -Field emission scanning electron microscope image of COF / GA composite adsorbent (b) and β - Photograph of the COF / GA composite adsorbent material (c).

[0023] Figure 2 It is the product of Example 1. β -COF and β XRD pattern (a) and TG curve (b) of the COF / GA composite adsorbent material.

[0024] Figure 3 It is the product of Example 1. β -COF and β The adsorption kinetics curves of phenol by the COF / GA composite adsorbent material (a) and (b) β - Adsorption and regeneration performance diagram of COF / GA composite adsorbent material (b).

[0025] Figure 4 The comparative example product is GA(a). β -COF / 15GA(b) and β -COF / 3GA(c) scanning electron microscope image.

[0026] Figure 5 yes β -COF, β -COF / GA, GA, β -COF / 15GA and β Comparison of the maximum adsorption performance of phenol by COF / 3GA.

[0027] Figure 6 These are field emission scanning electron microscope images of the products of Comparative Example 4, triazine COF (a) and triazine COF / GA composite aerogel (b). Implementation

[0028] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and examples. The following examples are only used to more clearly illustrate the technical solutions of the present invention, so that those skilled in the art can better understand and utilize the present invention, and are not intended to limit the scope of protection of the present invention.

[0029] Unless otherwise specified, the production processes, experimental methods, or testing methods involved in the embodiments and comparative examples of this invention are all conventional methods in the prior art, and their names and / or abbreviations are all conventional names in the art, which are very clear and distinct in the relevant application fields. Those skilled in the art can understand the conventional process steps based on the names and apply the corresponding equipment, and implement them according to conventional conditions or conditions recommended by the manufacturer.

[0030] The various instruments, equipment, raw materials or reagents used in the embodiments of this invention are not subject to any special restrictions on their source. They are all conventional products that can be purchased through regular commercial channels and can be prepared according to conventional methods known to those skilled in the art.

[0031] This invention first provides a suitable covalent organic framework material. β Preparation method of -COF:

[0032] Using 1,3,5-tricarboxymethyl phloroglucinol and aniline compounds (such as p-phenylenediamine and benzidine) as the synthetic... β The reaction raw materials for -COF are prepared using water as a solvent, with p-toluenesulfonic acid added to promote the dissolution of both raw materials in water. A hydrothermal reaction then occurs, causing the two raw materials to connect and form a six-membered ring structure. After necessary washing and vacuum drying, a water-stable powder is obtained. β -COF.

[0033] The raw materials used, 1,3,5-tricarboxyloyl-resenchymalol and aniline compounds, all had a purity of over 97%, while p-toluenesulfonic acid was of analytical grade.

[0034] Specifically, the preferred molar ratio of 1,3,5-tricarboxymethyl phloroglucinol to aniline compounds is 1:1 to 2, the preferred molar ratio of 1,3,5-tricarboxymethyl phloroglucinol to p-toluenesulfonic acid is 1:1 to 2, and the preferred molar ratio of 1,3,5-tricarboxymethyl phloroglucinol to water is 1:7000 to 8000.

[0035] More specifically, the preferred order of dissolving the various raw materials used in the hydrothermal reaction is as follows: first, add p-toluenesulfonic acid to water and sonicate at room temperature for 3–5 min; then, add aniline compounds dissolved in the p-toluenesulfonic acid aqueous solution and sonicate at room temperature for 10–15 min; finally, add 1,3,5-tricarboxymethyl phloroglucinol dissolved in the above mixed solution system and sonicate at room temperature for 30–40 min. More preferably, continuous stirring is maintained during the above dissolution process to ensure thorough and uniform mixing of the various raw materials.

[0036] Furthermore, the blended solution is placed in a hydrothermal reactor lined with polytetrafluoroethylene, sealed, and placed in an oven. The temperature is raised from room temperature to 100–150°C and maintained at a constant temperature for 18–36 hours to allow 1,3,5-tricarboxymethyl phloroglucinol to connect with aniline compounds to form a six-membered ring structural unit.

[0037] Furthermore, the hydrothermal reaction product is thoroughly washed with acetone and water in sequence to remove unreacted raw materials from the product.

[0038] Preferably, the washing is performed with acetone 3 to 5 times and with water 6 to 10 times.

[0039] Furthermore, the washed product is dried in a vacuum drying oven at 60°C for 2–4 days to remove residual solvent, thus obtaining a highly crystalline solid powder. β -COF.

[0040] Secondly, the present invention also provides a method based on the above. β -COF β Preparation method of COF / GA composite adsorbent material:

[0041] As stated β -COF is used as the reinforcing phase, graphene oxide as the carbon precursor, and ammonium citrate as the reducing agent. A liquid-phase reduction self-assembly reaction is carried out in water. β -COF is attached to the surface of the reduced graphene or in the channels formed by the assembly of sheets, and after dialysis to remove impurities and freeze-drying, an appropriate amount is achieved. β Loading of -COF on the surface and in the pores of graphene aerogel yields β -COF / GA composite adsorbent material.

[0042] The present invention preferably uses graphene oxide with a thickness of no more than 1µm and a single-layer diameter of 0.2 to 10µm as a carbon precursor, and preferably uses ammonium citrate with a purity of 98.5% or higher.

[0043] Specifically, it uses an aqueous solution of graphene oxide, an aqueous solution of ammonium citrate, and... β - After thorough blending of COF solid powder at room temperature, a liquid-phase reduction self-assembly reaction is carried out, causing graphene oxide to be reduced and exhibit self-assembly behavior, while simultaneously loading... β -COF, forming β -COF / graphene composite hydrogel, after dialyzing in an ethanol-water solution, was freeze-dried to form β -COF / GA composite adsorbent material.

[0044] More specifically, the concentration of the graphene oxide aqueous solution is 3-5 g / L, and the concentration of the ammonium citrate aqueous solution is 50-80 g / L. Preferably, the mass ratio of graphene oxide to ammonium citrate is 1:3-7. β The mass ratio of -COF to graphene oxide is 1:5 to 15.

[0045] More specifically, the present invention preferably involves first adding graphene oxide to water and ultrasonically dispersing it at room temperature for 1–2 hours; then adding… β -COF, continue ultrasonic dispersion for 10-15 min; then add ammonium citrate aqueous solution to the reaction system at a rate of 3-5 drops per second during ultrasonication. After the addition is complete, stir the mixed reaction system at 25℃ for 10-15 min to ensure that graphene oxide, β-COF and ammonium citrate are mixed evenly in aqueous solution.

[0046] Furthermore, the liquid-phase reduction self-assembly reaction specifically involves placing the above mixed solution in a polytetrafluoroethylene-lined hydrothermal reactor, sealing it, and then placing it in an oven. The temperature is raised from room temperature to 100–150°C, and the reaction is maintained at this temperature for 8–15 hours to reduce and encapsulate the graphene oxide. β -COF, formed through self-assembly β -COF / graphene composite hydrogel.

[0047] Furthermore, an ethanol-water aqueous solution with a preferred volume ratio of 4 to 8:1 is prepared and placed in... β - COF / graphene composite hydrogels are dialyzed to remove unreacted raw materials.

[0048] The specific number of dialysis sessions is 4 to 6, and the dialysis time is 2 to 3 days.

[0049] Furthermore, finally, the post-dialysis β - The COF / graphene composite hydrogel was placed in a freezer at -80°C or below to allow it to... β The water in the COF / graphene composite hydrogel was freeze-cured and then freeze-dried at -80°C for 3–5 days in a freeze-drying oven. β After the solid water in the COF / graphene composite hydrogel sublimates, it yields... β -COF / GA composite adsorbent material. Example

[0050] Example 1

[0051] Weigh 64 mg of p-toluenesulfonic acid into a glass bottle containing 5 mL of deionized water, and sonicate at 25 °C for 3 min to fully dissolve it to obtain an aqueous solution of p-toluenesulfonic acid.

[0052] Weigh 6 mg of p-phenylenediamine into the above-mentioned p-toluenesulfonic acid aqueous solution, and sonicate it at 25°C for 10 min to fully dissolve it to obtain a mixed aqueous solution.

[0053] Weigh 7.8 mg of 1,3,5-tricarboxymethyl phloroglucinol and add it to the above mixed aqueous solution. Continue sonicating for 30 min and continuously stir manually to ensure thorough and uniform mixing to obtain a blended solution.

[0054] The blended solution was transferred to a polytetrafluoroethylene-lined hydrothermal reactor, sealed and placed in an oven, and heated to 120°C for a constant hydrothermal reaction for 24 hours to allow 1,3,5-tricarboxymethyl phloroglucinol and p-phenylenediamine to fully react and connect to form a six-membered ring structural unit.

[0055] After cooling, the hydrothermal reaction product was washed three times with acetone, followed by six more washes with water. It was then dried in a vacuum drying oven at 60°C for 3 days to remove residual solvent, yielding a solid powder. β -COF.

[0056] Weigh 0.24 g of graphene oxide into a beaker containing 80 mL of deionized water, and sonicate it at 25 °C for 1.5 h to obtain a uniformly dispersed graphene oxide dispersion.

[0057] Weigh 1g of ammonium citrate into 20mL and sonicate at 25℃ for 10min to fully dissolve it to obtain an aqueous solution of ammonium citrate.

[0058] Measure 12 mL of the graphene oxide dispersion into a cylindrical glass bottle, and add 4 mg of the above-mentioned... β -COF powder was added dropwise at a rate of 3 drops per second to 3.6 mL of ammonium citrate aqueous solution. After the addition was complete, the mixed reaction system was stirred at 25°C for 15 min to ensure the stability of the graphene oxide. β -COF and ammonium citrate are mixed evenly in aqueous solution.

[0059] The above mixed solution was transferred to a polytetrafluoroethylene-lined hydrothermal reactor, sealed, and placed in an oven. The reactor was heated to 120°C and kept at a constant temperature for 12 hours to allow the graphene oxide to be reduced and encapsulated. β -COF, formed through self-assembly β -COF / graphene composite hydrogel.

[0060] The result β The COF / graphene composite hydrogel was dialyzed in an 85% ethanol aqueous solution, with the dialysate changed every 12 hours for four times. After rinsing repeatedly with water to remove unreacted materials, it was then freeze-dried in a freezer at -80°C or below, and then freeze-dried in a freeze-drying oven at -80°C or below for 3 days. β Solid water sublimation in COF / graphene composite hydrogels yields... β -Bulk COF with a mass ratio of 1:9 to graphene oxide β -COF / GA composite adsorbent material.

[0061] Figure 1 The above preparation β -COF(a) and β -Field emission scanning electron microscope image of COF / GA composite adsorbent (b) and β -A photograph of the COF / GA composite adsorbent material (c). It can be seen that... β -COF exhibits a sea urchin-like microstructure and is obtained after being combined with GA. β-COF / GA composite adsorbent materials are formed by stacking and connecting large-sized graphene sheets, and a large number of graphene surfaces and the channels formed by the assembly of the sheets are attached to them. β -COF. (See actual product photo) β - The COF / GA composite adsorbent material is a black cylindrical material with a cross-sectional diameter of 1 cm and a height of 1.5 cm. It can be directly immersed in the solution for adsorption, making the adsorption process more convenient and facilitating the recycling and regeneration of the adsorbent material.

[0062] Figure 2 of β -COF and β The XRD pattern of the COF / GA composite adsorbent material (a) shows... β -COF at 2 θ A diffraction characteristic peak appears at 4.5°. β -COF / GA composite adsorbent materials, on the other hand, are in 2 θ Diffraction peaks appear at 4.5° and 26°, respectively, corresponding to β -COF characteristic peaks and carbon-encapsulated peaks confirm that β -CoF and GA recombination. Furthermore, as can be seen from the TG curve (b), β -COF has a total thermogravimetric loss rate of 48.5% at 800℃. Due to the good thermal stability of GA as a carbon material, β -The total thermogravimetric loss rate of the COF / GA composite adsorbent material at 800℃ is only 25.0%, and because β The thermal decomposition of -COF makes β The thermogravimetric curve of the COF / GA composite adsorbent material decreases rapidly in the range of 450–500℃.

[0063] Figure 3 Given β -COF and β The adsorption kinetics curves of phenol by the COF / GA composite adsorbent material are shown in (a) and (b) respectively. β -Adsorption and regeneration performance diagram of the COF / GA composite adsorbent material (b). It can be seen that in (a), under the same adsorption conditions, β The saturated adsorption capacity of COF for phenol is only 28.15 mg / g. -1 The main reason for this is its highly microporous structure and the attraction of nitrogen and oxygen functional groups to phenol; and when it is used as a reinforcing phase and combined with GA, it makes... β The saturated adsorption capacity of the COF / GA composite adsorbent for phenol increased to 55.91 mg / g. -1 Furthermore, due to its blocky shape β- The COF / GA composite adsorbent has good mechanical properties and can be recycled multiple times. In (b), after the first adsorption saturation, after 5 elution regeneration-phenol adsorption cycle tests, the saturated adsorption capacity for phenol can still be maintained at 94.27% of the first saturated adsorption capacity.

[0064] In addition, in Table 1 β -COF and β Comparison of specific surface area and pore structure data of COF / GA composite adsorbent materials β -COF has an extremely high micropore content, and its micropore specific surface area is... S micro The value reached 929.240m 2 g -1 The rich microporous structure enables the corresponding β -COF / GA composite adsorbent materials also possess a certain microporous structure. S micro The value is 148.312m 2 g -1 This is beneficial for increasing the adsorption capacity of the material for phenol.

[0065] Comparative Example 1

[0066] Weigh 0.24 g of graphene oxide into a beaker containing 80 mL of deionized water, and sonicate it at 25 °C for 1.5 h to obtain a uniformly dispersed graphene oxide dispersion.

[0067] Weigh 1g of ammonium citrate into 20mL and sonicate at 25℃ for 10min to fully dissolve it to obtain an aqueous solution of ammonium citrate.

[0068] Measure 12 mL of graphene oxide dispersion into a cylindrical glass bottle, and add 3.6 mL of ammonium citrate aqueous solution dropwise at a rate of 3 drops per second. After the addition is complete, continue stirring the mixed reaction system at 25°C for 15 min to ensure that the graphene oxide and ammonium citrate are mixed evenly in the aqueous solution.

[0069] The above mixed solution was transferred to a polytetrafluoroethylene-lined hydrothermal reactor, sealed and placed in an oven, and heated to 120°C for a constant temperature hydrothermal reaction for 12 hours, so that the graphene oxide was reduced and self-assembled to form a graphene hydrogel.

[0070] The obtained graphene hydrogel was dialyzed in an 85% ethanol aqueous solution, with the dialysate changed every 12 hours, for a total of 4 times. After rinsing repeatedly with water to remove unreacted raw materials, the hydrogel was placed in a freezer at -80°C or below for freeze solidification, and then placed in a freeze-drying oven at -80°C or below for 3 days to sublimate the solid water in the graphene hydrogel, thus obtaining a solution free of... β Bulk graphene adsorbents with -COF are denoted as GA.

[0071] GA's scanning electron microscope image, such as Figure 4 As shown in (a), the adsorbent material is formed by stacking and connecting relatively large, smooth, and flat graphene sheets, and the graphene surface and sheet assembly form a rich hierarchical pore structure. This structure ensures that the adsorbent material is bulk and has good mechanical properties. However, according to the specific surface area and pore structure data of GA in Table 1, it lacks a microporous structure.

[0072] from Figure 5 As observed, under the same adsorption conditions, the saturated adsorption capacity of GA for phenol was only 19.74 mg g. -1 This is mainly due to its π–π interaction with phenol and hydrogen bonding.

[0073] Figure 5 In Example 1, the preparation β The saturated adsorption capacity of -COF is only 28.15 mg g. -1 However, when the two are combined in an appropriate ratio, β The saturated adsorption capacity of the COF / GA composite adsorbent material for phenol significantly increased to 55.91 mg / g. -1 This indicates β The introduction of -COF can effectively improve the overall micropore content and adsorption activity of the adsorption material.

[0074] Example 2

[0075] Weigh 67 mg of p-toluenesulfonic acid into a glass bottle containing 5 mL of deionized water, and sonicate at 25 °C for 5 min to fully dissolve it to obtain an aqueous solution of p-toluenesulfonic acid.

[0076] Weigh 6.5 mg of p-phenylenediamine into the above-mentioned p-toluenesulfonic acid aqueous solution, and sonicate at 25°C for 13 min to fully dissolve it to obtain a mixed aqueous solution.

[0077] Weigh 8 mg of 1,3,5-tricarboxymethyl phloroglucinol and add it to the above mixed aqueous solution. Continue sonicating for 40 min and continuously stir manually to ensure thorough and uniform mixing to obtain a blended solution.

[0078] The blended solution was transferred to a polytetrafluoroethylene-lined hydrothermal reactor, sealed and placed in an oven, and heated to 125°C for a constant hydrothermal reaction for 25 hours to allow 1,3,5-tricarboxymethyl phloroglucinol and p-phenylenediamine to fully react and connect to form a six-membered ring structural unit.

[0079] After cooling, the hydrothermal reaction product was washed four times with acetone, followed by five more washes with water. It was then dried in a vacuum oven at 60°C for 2.5 days to remove residual solvent, yielding a solid powder. β -COF.

[0080] Prepared as described above β -COF powder was used to prepare a composite adsorbent material according to the method in Example 1, and obtained β -Bulk COF with a mass ratio of 1:9 to graphene oxide β -COF / GA composite adsorbent material.

[0081] Tests showed that its properties and phenol adsorption performance were consistent with the composite adsorbent material in Example 1.

[0082] Example 3

[0083] Weigh 0.27 g of graphene oxide into a beaker containing 80 mL of deionized water, and sonicate it at 25 °C for 1.6 h to obtain a uniformly dispersed graphene oxide dispersion.

[0084] Weigh 1.1 g of ammonium citrate into 20 mL and sonicate at 25 °C for 12 min to fully dissolve it to obtain an aqueous solution of ammonium citrate.

[0085] Measure 12 mL of graphene oxide dispersion into a cylindrical glass bottle, and add 4 mg of the solution prepared in Example 1. β -COF powder was added dropwise at a rate of 4 drops per second to 3.8 mL of ammonium citrate aqueous solution. After the addition was complete, the mixed reaction system was stirred at 25°C for 13 min to ensure the stability of the graphene oxide. β -COF and ammonium citrate are mixed evenly in aqueous solution.

[0086] The above mixed solution was transferred to a polytetrafluoroethylene-lined hydrothermal reactor, sealed, and placed in an oven. The reactor was heated to 130°C and kept at a constant temperature for 15 hours to allow the graphene oxide to be reduced and encapsulated. β -COF, formed through self-assembly β -COF / graphene composite hydrogel.

[0087] The result β The COF / graphene composite hydrogel was dialyzed in a 75% ethanol aqueous solution, with the dialysate changed every 12 hours, for a total of 5 times. After rinsing repeatedly with water to remove unreacted raw materials, it was then freeze-dried in a freezer at -80°C or below, and then freeze-dried in a freeze-drying oven at -80°C or below for 2 days. β Solid water sublimation in COF / graphene composite hydrogels yields... β -Bulk COF with a mass ratio of 1:9 to graphene oxide β -COF / GA composite adsorbent material.

[0088] Tests showed that its properties and phenol adsorption performance were consistent with the composite adsorbent material in Example 1.

[0089] Example 4

[0090] In addition to β Except for reducing the amount of COF powder from 4 mg to 2.4 mg, all other reaction conditions were exactly the same as in Example 1, and the prepared product was obtained. β A bulk composite adsorbent material with a COF to graphene oxide mass ratio of 1:15 is denoted as... β -COF / 15GA.

[0091] β -COF / 15GA scanning electron microscope image such as Figure 4 As shown in (b), it can be seen that due to only a small amount β -COF is added to the composite reaction system, in β Only a few traces of COF / 15GA are present in the microstructure. β -COF is loaded onto the GA surface.

[0092] Table 1 β The specific surface area and pore structure data of -COF / 15GA are significantly better than those of GA due to its higher micropore content. β -COF addition makes β The micropore content of -COF / 15GA is higher than that of GA. S micro The value is 93.554m 2 g -1 The product of Example 1 β -COF / GA comparison, due to the load of Example 1 β -COF is present in greater quantities. β -COF / 15GA has a micropore content of less than β -COF / GA.

[0093] Further according to Figure 5 As can be seen, under the same adsorption conditions, β The saturated adsorption capacity of COF / 15GA for phenol is 45.41 mg / g. -1 Higher than the unrecombined β -The adsorption capacity of COF and GA, but due to β The amount of COF added was relatively small, and its adsorption capacity was still slightly lower than that of the product in Example 1. β -COF / GA phenol adsorption value.

[0094] Comparative Example 2

[0095] In addition to β Except for increasing the amount of COF powder from 4 mg to 12 mg, all other reaction conditions were exactly the same as in Example 1, and the prepared product was obtained. βA bulk composite adsorbent material with a COF to graphene oxide mass ratio of 1:3 is denoted as... β -COF / 3GA.

[0096] β -COF / 3GA scanning electron microscope images such as Figure 4 As shown in (c), it can be seen that due to excessive β -COF is added to the complex reaction system, in β A large number of microstructures of -COF / 3GA appeared β -COF buildup and agglomeration loads on the GA surface, causing the GA's channels to be stretched and destroyed.

[0097] Table 1 β The specific surface area and pore structure data of -COF / 3GA are the same as those of GA and β Compared to -COF / 15GA, due to its higher micropore content... β The amount of -COF is greater, making β -COF / 3GA has a higher micropore content than GA and β -COF / 15GA, its S micro The value is 109.565m 2 g -1 .but β The micropore content of -COF / 3GA is less than that of the product in Example 1. β -COF / GA, this is due to although β -COF / 3GA loads more β -COF, but β Excessive loading of COF in the same region of the aerogel leads to rigid one-dimensional channels. β - Severe COF accumulation and disruption of the aerogel pore structure; this structural damage also makes... Figure 5 middle β The saturated adsorption capacity of COF / 3GA for phenol decreased to 25.64 mg / g. -1 .

[0098]

[0099] Therefore, based on the above characterization data, β -COF / GA composite adsorbent materials β - The COF content should not be too high. This invention limits its maximum mass ratio with graphene oxide to 1:5.

[0100] Comparative Example 4

[0101] A mixed solution was obtained by mixing 1 mL of ethanol and 1 mL of 1,2-dichlorobenzene solution in a glass bottle.

[0102] Weigh 20.5 mg of 4,4',4''-(1,3,5-triazine-2,4,6-triyl)triphenylamine and 11.6 mg of terephthalaldehyde into the above mixed solution, add 0.2 mL of 6M acetic acid solution dropwise, and sonicate for 15 min.

[0103] The mixed solution was transferred to a polytetrafluoroethylene-lined hydrothermal reactor, sealed, and placed in an oven. The temperature was raised to 120°C and kept constant for 72 hours for hydrothermal reaction.

[0104] After cooling, the hydrothermal reaction product was washed three times each with ethanol and tetrahydrofuran, and then dried in a vacuum drying oven at 45°C for 3 days to remove the solvent, yielding a solid powder of triazine COF.

[0105] Replace the triazine COF obtained above in Example 1 β -COF powder, and the preparation of the composite adsorbent material is exactly the same as in Example 1, to obtain a bulk triazine COF / GA composite aerogel with a mass ratio of triazine COF to graphene oxide of 1:9.

[0106] Figure 6 These are field emission scanning electron microscope images of the prepared triazine COF (a) and triazine COF / GA composite aerogel (b). It can be seen that the triazine COF consists of agglomerated particles with a regular microstructure. However, the microstructure of the triazine COF / GA composite aerogel produced after the composite hydrothermal reaction is more similar to that of the GA product in Comparative Example 1, consisting of stacked graphene sheets. Triazine COF particles are difficult to observe on the graphene sheets and in the pore structure. This is because triazine COF has relatively poor stability in the aqueous phase, and thus, during the composite hydrothermal process, as the graphene hydrogel forms, the triazine COF decomposes, preventing the two from being composited.

[0107] The above embodiments of the present invention do not describe all details exhaustively, nor do they limit the present invention to the embodiments described above. Various changes, modifications, substitutions, and variations made by those skilled in the art to these embodiments without departing from the principles and spirit of the present invention should be included within the scope of protection of the present invention.

Claims

1. A β -COF / GA composite adsorption material, graphene oxide is used as carbon precursor, and the enhanced phase β -COF is blended to form an aqueous solution system, a reducing agent ammonium citrate is added to carry out a liquid phase reduction self-assembly reaction, and β -COF is loaded on the surface and pores of the reduced graphene aerogel to obtain an adsorption material, wherein, reinforcing phase β The mass ratio of COF to graphene oxide is 1:5-15, and the reinforcing phase β The COF is a water phase stable powdery COF obtained by using 1,3,5-triformylphloroglucinol and an aniline compound as raw materials, using water as a solvent, and adding p-toluenesulfonic acid to promote the dissolution of the raw materials in water, and then performing a hydrothermal reaction. β COF.

2. The method of claim 1 β A method for preparing a COF / GA composite adsorbent material, characterized by: 1), 1,3,5-triformylphloroglucinol and aniline compounds as raw materials, water as solvent and p-toluenesulfonic acid to promote the dissolution of raw materials in water, hydrothermal reaction to make the raw materials connected to form six-membered ring structure unit, get water phase stable powder β -COF; 2), with β -COF is the reinforcing phase, graphene oxide is the carbon precursor, ammonium citrate is the reducing agent, and the mixture is dissolved in water to carry out liquid phase reduction self-assembly reaction, so as to reduce graphene oxide and produce self-assembly behavior, and then β -COF is loaded on the surface and pores of graphene to form β -COF / Graphene composite hydrogel, freeze-dried to obtain β -COF / GA composite adsorption material.

3. The method of claim 2, wherein the method further comprises: β A method for preparing a COF / GA composite adsorbent material, characterized by The aniline compound is p-phenylenediamine or benzidine.

4. The method of claim 2, wherein the method further comprises: β A method for preparing a COF / GA composite adsorbent material, characterized by The molar ratio of 1,3,5-triformylphloroglucinol to the aniline compound is 1:1-2, and the molar ratio of 1,3,5-triformylphloroglucinol to p-toluenesulfonic acid is 1:1-2.

5. The method of claim 2, wherein the method further comprises: β A method for preparing a COF / GA composite adsorbent material, characterized by The hydrothermal reaction is constant temperature hydrothermal reaction at 100-150 ℃ for 18-36 h.

6. The method of claim 2, wherein the method further comprises: β A method for preparing a COF / GA composite adsorbent material, characterized by The mass ratio of the β-COF to the graphene oxide is 1:5-15, and the mass ratio of the graphene oxide to the ammonium citrate is 1:3-7.

7. The method of claim 2, wherein the method further comprises: β A method for preparing a COF / GA composite adsorbent material, characterized by The liquid phase reduction self-assembly reaction is constant temperature hydrothermal reaction at 100-150 ℃ for 8-15 h.

8. The method of claim 1 β Use of the COF / GA composite adsorbent material as an adsorption removal agent for phenol molecules in aqueous solution.

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