Hollow special-hole adsorption material as well as preparation method and application thereof
By preparing hollow heteroporous covalent organic framework material HCOFs, the problem of inaccessibility of pores inside covalent organic framework material is solved, efficient adsorption and enrichment of food hazardous substances is achieved, and the efficiency and accuracy of food safety detection are improved.
Patent Information
- Application Number
- CN202310975494.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-08-04
- Publication Date
- 2025-02-14
AI Technical Summary
The internal pores of existing covalent organic frame materials are difficult to get close, which limits their application in food samples, resulting in low adsorption efficiency and difficult to achieve efficient enrichment and detection of food hazardous substances.
ETTA and BPDA were dissolved in acetonitrile, and acetic acid was added to the reaction to obtain the composite heteroporous covalent organic framework material COFs. The hollow heteroporous covalent organic framework material HCOFs was prepared through amino modification and template removal methods to realize the hollowness of the material. Structure and efficient adsorption capacity.
The prepared hollow heteroporous adsorption material has significant and efficient adsorption ability, which can preferentially adsorption target interfering molecules, increase adsorption speed and quantity, and remain stable in acidic, alkaline and organic solvents. It is suitable for sample pretreatment of complex substrates, achieving High-precision detection of chemical hazards.
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Figure CN119425626A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of material preparation, and in particular relates to a hollow heteroporous adsorption material and a preparation method and application thereof. Background Art
[0002] Risk factors for food safety From farmland to dining table, there may be factors that affect food safety at every stage, such as microbial hazards, heavy metal pollution, pesticide and veterinary drug residues, excessive additives, hazards in the processing, storage and packaging process, persistent organic pollutants, biological toxins and food adulteration, etc., which pose a great threat to the life and health of consumers. The importance of food testing for food safety should be implemented in specific industry norms and standards, so as to avoid food safety problems, fully protect people's health, and the food industry can achieve sustainable development and progress. Food testing technology is constantly developing, and traditional testing methods can no longer meet the safety testing needs of modern food, and food matrices are often more complex. Therefore, more efficient and convenient testing methods are urgently needed to better control food safety issues and promote the food industry to develop in a green and safe direction.
[0003] Covalent organic frameworks are porous crystalline polymers composed of light elements such as carbon, boron, oxygen and silicon connected by strong covalent bonds in 2D or 3D topology. In COF, the secondary building units are firmly held by strong covalent bonds between carbon-nitrogen, boron-oxygen, silicon-carbon or boron-oxygen-silicon, so they have strong chemical stability. Since it can be designed into a target framework structure or functional group for the bonding of target pollutants, it can achieve efficient adsorption of target hazards and become a hot topic in the field of detection. The prepared covalent organic framework has high-intensity pores, but its contribution mainly comes from the pores distributed on the surface of the covalent organic framework. Most of the internal pores cannot play a role due to inaccessibility, which greatly limits its application in actual samples. Developing new hollow heteroporous adsorption materials, reducing the transmission distance from the target to the material, improving the adsorption efficiency of the material for the target pollutant, and ultimately achieving the enrichment and detection of food hazards, provides a technical basis and important social value for the efficient detection, effective supervision and control of hazards in food. Summary of the invention
[0004] In order to solve the above technical problems, the present invention provides a hollow heteroporous adsorption material and a preparation method and application thereof.
[0005] The technical scheme adopted by the present invention is: a method for preparing a hollow heteroporous adsorption material, wherein ETTA and BPDA are dissolved in acetonitrile, acetic acid is added after dispersion, and a closed reaction is performed at 120° C. to obtain a composite heteroporous covalent organic framework material COFs.
[0006] Preferably, the amino-modified nanoparticles are dissolved in acetonitrile together with ETTA and BPDA. After the reaction in an autoclave, the resulting product is treated with hydrofluoric acid to remove the template, thereby obtaining a hollow heteroporous covalent organic framework material HCOFs.
[0007] Preferably, aqueous ammonia is added to a mixture of anhydrous ethanol and high-purity water, tetraethyl orthosilicate is added at 40° C., and 3-aminopropyltriethoxysilane is added and stirred to obtain amino-modified nanoparticles SiO2-NH2.
[0008] Preferably, the specific preparation method is as follows:
[0009] Step 1: Add ammonia water to a mixture of anhydrous ethanol and high-purity water, add tetraethyl orthosilicate at 40°C, and then add 3-aminopropyltriethoxysilane and stir to obtain amino-modified nanoparticles SiO2-NH2;
[0010] Step 2: Dissolve SiO2-NH2, ETTA and BPDA in acetonitrile, disperse them evenly and then slowly add 6M acetic acid, place them in a reactor, and react at 120°C to obtain a composite heteroporous covalent organic framework material SiO2-NH2@COFs;
[0011] Step 3: Treat SiO2-NH2@COFs with HF to obtain hollow heteroporous covalent organic framework material HCOFs.
[0012] Preferably, the ratio of water to ammonia water is 1:10.
[0013] The hollow heteroporous adsorption material is prepared by the preparation method of the hollow heteroporous adsorption material.
[0014] Application of hollow heteroporous adsorbent materials in food testing and food contaminant removal.
[0015] Preferably, HCOF is placed in a target solution and adsorbed by vibration to achieve enrichment of interfering matrix in the sample.
[0016] Preferably, a buffer and HCOFs are added to the target solution, and the buffer is Tris-HCl;
[0017] The adsorbed HCOFs are eluted by an eluent, which is acetone; the eluted HCOFs can be used again for adsorption or enrichment of interfering matrices.
[0018] The advantages and positive effects of the present invention are as follows: the prepared hollow heteroporous adsorption material has two pore sizes matching the target molecules, has a significant and efficient preferential adsorption capacity for the target interfering molecules, and the hollow structure of the material greatly improves the adsorption speed and adsorption amount; the hollow heteroporous adsorption material has higher chemical stability and thermal stability, exists stably in acidic, alkaline and organic solvents, is suitable for sample pretreatment of complex matrices, can achieve matrix purification, thereby performing non-targeted screening of chemical hazards in the matrix, and achieving high-precision confirmation of trace chemical hazards in complex food matrices. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 :Characterization of COFs and HCOFs: (A) N2 adsorption-desorption isotherms of COFs and HCOFs; (B) Pore size distribution of COFs and HCOFs; (C) Dynamic light scattering of HCOFs; (D) SiO2-NH2; (E) COFs; (F) SiO2-NH2@COFs; (G) Transmission electron microscopy of HCOFs; (H) Fourier transform infrared spectra of SiO2-NH2, SiO2-NH2@COFs, HCOFs and COFs; (I) Powder X-ray diffraction patterns of SiO2-NH2@COFs, HCOFs and COFs; (J) Thermogravimetric curves of HCOFs and COFs;
[0020] Figure 2 :Evaluation of HCOFs' ability to remove pigment matrix: (A) UV-visible absorption spectra before and after purification of extracts using 1-20 mg HCOFs; (B) Pigment removal rate corresponding to the UV-visible spectra; (C) Pigment removal rate after adsorption using 1 mg / mL HCOFs in different types of buffer solutions; (D) Removal rate of photosensitive pigments under conditions of different buffer concentrations; (F) Removal rate of photosensitive pigments under conditions of different pH values; (G) Elution efficiency of different eluents; (G) Variation of elution efficiency over time during acetone elution;
[0021] Figure 3 : Relationship between the removal of plant pigments by HCOFs and original COFs over time: (A) UV-visible absorption spectrum of pigments changing with time when 1 mg / mL HCOFs was used to purify spinach extract; (B) UV-visible absorption spectrum of pigments changing with time when 1 mg / mL original COFs was used to purify spinach extract; (C) Efficiency of HCOFs in removing plant pigments at different times; (D) Efficiency of original COFs in removing plant pigments at different times;
[0022] Figure 4 : Repeatability evaluation of hollow heteroporous adsorption materials. DETAILED DESCRIPTION
[0023] The embodiments of the present invention are described below with reference to the accompanying drawings.
[0024] The present invention relates to a hollow heteroporous adsorption material and a preparation method and application thereof. A covalent organic framework material is introduced, and an in-situ growth method is adopted to prepare a new type of composite heteroporous material with a core-shell structure having strong adsorption and large specific surface area. Then, the core-shell composite framework material is etched to obtain a hollow structure through a sacrificial template method, and a hollow heteroporous adsorption material is synthesized to achieve selective adsorption and efficient enrichment of photosensitive pigments, purify complex sample matrices, and thus perform non-targeted screening of chemical hazards in the matrix. Covalent organic framework materials are a new type of organic polymer with a uniform and ordered crystal structure, composed of light elements, and are crystalline materials formed by orderly assembly of organic units constructed by reversible chemical reactions. Based on their excellent stability and high comparative area, they become potential sample pretreatment materials. This material is combined with a specific sacrificial template, and an in-situ growth method is adopted to form a new composite adsorption material with a core-shell structure.
[0025] The hollow heteroporous adsorption material can be prepared in the following manner.
[0026] A covalent organic framework material with a specific pore size was prepared for the target photosensitive pigment; ETTA and BPDA were dissolved in acetonitrile, and 6M acetic acid was slowly added after ultrasonic dispersion. The reactants were transferred to a reactor and placed in liquid nitrogen for 20 minutes for freezing and degassing. After the temperature rose to room temperature, the reaction was carried out at 120°C for 3 days. After the reaction was completed, the product was washed alternately with ethanol or high-purity water several times, and vacuum dried at 60°C to obtain a composite heteroporous covalent organic framework material COFs.
[0027] In some embodiments of the present invention, the hollow heteroporous adsorption material can also be prepared according to the following steps.
[0028] Step 1: Add 2.0 mL of ammonia water to a mixture of 80 mL of anhydrous ethanol and 20 mL of high-purity water, add 0.5 mL of tetraethyl orthosilicate and stir mechanically at 40°C for 10 h, add 0.5 mL of 3-aminopropyltriethoxysilane and stir for 10 h, wherein the molar ratio of tetraethyl orthosilicate to 3-aminopropyltriethoxysilane is 1:1. After the reaction is completed, the product is washed alternately with ethanol or high-purity water for several times, and dried in vacuo at 60°C to obtain amino-modified nanoparticles (SiO2-NH2);
[0029] Step 2: Dissolve 20 mg SiO2-NH2, 20 mg ETTA, and 21.4 mg BPDA in acetonitrile, where the molar ratio of ETTA to BPDA is 2:3. After ultrasonic dispersion, slowly add 6 M acetic acid, transfer the reactants to a reactor, place them in liquid nitrogen for 20 min of freezing and degassing, and after the temperature rises to room temperature, react at 120 ° C for 3 days. After the reaction is completed, the product is washed alternately with ethanol or high-purity water for several times, and vacuum dried at 60 ° C to obtain the composite heteroporous covalent organic framework material SiO2-NH2@COFs;
[0030] Step 3: Add 20 mg SiO2-NH2@COFs to 5% HF, ultrasonicate for 15 min, wash alternately with methanol and ultrapure water, and finally dry under vacuum to obtain a hollow heteroporous covalent organic framework material HCOFs.
[0031] The prepared hollow heteroporous covalent organic framework material has a typical hollow structure. A simple in situ growth method is used to successfully grow a covalent organic framework on the surface of the metal organic framework to form a core-shell structure composite material. Then, the hollow structure is introduced into the covalent organic framework material by acid etching the acid-sensitive metal organic framework through a sacrificial template method.
[0032] Combined with UV-visible spectrophotometer and liquid chromatography-mass spectrometry and other analytical methods, interfering matrices and chemical hazards in complex matrix samples are detected and screened. The prepared hollow heteroporous adsorption material has a specific pore size and good particle size uniformity. It has a significant and efficient preferential adsorption capacity for target interfering molecules, and the hollow structure of the material greatly improves the adsorption speed and adsorption amount. At the same time, the hollow heteroporous adsorption material has higher chemical stability and thermal stability, and exists stably in a variety of organic solvents, which is suitable for sample pretreatment of complex matrices.
[0033] The prepared hollow heteroporous covalent organic framework material HCOFs can be used for food safety testing. Due to its advantages such as high porosity, good chemical and thermal stability and high reusability, it can give full play to the efficient adsorption performance of porous materials and ensure its stable application in complex food matrices, thereby achieving efficient enrichment, effective supervision and control of target pollutants.
[0034] Ethylenediamine N-propylsilane, graphitized carbon black and C 18Silane, etc., while interfering with the efficient removal of the matrix, also took away part or even a large amount of pollutants to be tested, thereby causing the omission of chemical pollutants, resulting in the occurrence of false negative results. The hollow heteroporous adsorption material prepared by the present invention has two different pore sizes, and the pore size matching degree with the photosensitive pigment is high, the chemical stability and thermal stability are good, the synthesis step is simple and the advantages of high reusability can give full play to the high adsorption performance of the hollow structure, and can ensure its preferential adsorption to the interfering matrix, and then realize the application of non-directional screening. A hollow heteroporous covalent organic framework adsorption material with a matching pore size is prepared for the target molecule pore size, introduced into food safety detection, and preferential adsorption for the target interfering matrix is realized, the sample matrix is purified, and the non-targeted screening of chemical hazards is realized. At the same time, the high reusability of the hollow heteroporous adsorption material is consistent with the current environmental protection concept, for further strict monitoring and control of hazardous substances in food, the formulation of the limit standard of hazardous substances in food provides technical support, and the application of analytical chemistry methodology based on advanced functional materials in food safety and human health science has important leading significance.
[0035] The scheme of the present invention is described below in conjunction with the accompanying drawings, wherein the experimental methods without specific operating steps are all carried out in accordance with the corresponding product instructions, and the instruments, reagents, and consumables used in the examples can all be purchased from commercial companies unless otherwise specified.
[0036] Example 1: Preparation of composite heteroporous covalent organic framework materials COFs
[0037] For the target photosensitive pigment, a covalent organic framework material with a specific pore size was prepared. 20 mg ETTA and 21.4 mg BPDA were dissolved in 3 mL acetonitrile, and 0.3 mL 6 M acetic acid was slowly added after ultrasonic dispersion. The reactants were transferred to a reactor and placed in liquid nitrogen for 20 min for freezing and degassing. After the temperature rose to room temperature, the reaction was carried out at 120 ° C for 3 days. After the reaction was completed, the product was washed alternately with ethanol or high-purity water several times, and vacuum dried at 60 ° C for 3 h to obtain a composite heteroporous covalent organic framework material COFs.
[0038] Example 2: Preparation of Hollow Heteroporous Covalent Organic Framework Materials HCOFs
[0039] Preparation of SiO2-NH2: 80 mL of anhydrous ethanol and 20 mL of high-purity water were measured, and then 2.0 mL of ammonia water and 0.5 mL of tetraethyl orthosilicate were added and mechanically stirred at 40°C for 10 h, and 0.5 mL of 3-aminopropyltriethoxysilane was added and stirred for 10 h. After the reaction was completed, the product was washed alternately with ethanol or high-purity water for several times, and vacuum dried at 60°C for 3 h to obtain amino-modified nanoparticles (SiO2-NH2);
[0040] Preparation of SiO2-NH2@COFs: 20 mg of SiO2-NH2, 20 mg of ETTA, and 21.4 mg of BPDA were dissolved in 3 mL of acetonitrile, and 0.3 mL of 6 M acetic acid was slowly added after ultrasonic dispersion. The reactants were transferred to a reactor and placed in liquid nitrogen for 20 min for freezing and degassing. After the temperature rose to room temperature, the reaction was carried out at 120 °C for 3 days. After the reaction was completed, the product was washed alternately with ethanol or high-purity water for several times, and vacuum dried at 60 °C for 3 h to obtain the composite heteroporous covalent organic framework material SiO2-NH2@COFs.
[0041] Weigh 20 mg of SiO2-NH2@COFs and add it to 10 mL of 5% HF, ultrasonicate for 15 min, wash it alternately with methanol and ultrapure water for 5 times, and finally dry it under vacuum for 3 h to obtain the hollow heteroporous covalent organic framework material HCOFs.
[0042] The physical and chemical properties of the products prepared in Example 1 and Example 2 were characterized. Figure 1 As shown, among them, (A) N2 adsorption-desorption isotherms of COFs and HCOFs; (B) pore size distribution of COFs and HCOFs; (C) dynamic light scattering of HCOFs; (D) SiO2-NH2; (E) COFs; (F) SiO2-NH2@COFs; (G) transmission electron microscopy of HCOFs; (H) Fourier transform infrared spectra of SiO2-NH2, SiO2-NH2@COFs, HCOFs and COFs; (I) powder X-ray diffraction of SiO2-NH2@COFs, HCOFs and COFs; (J) thermogravimetric curves of HCOFs and COFs. It can be seen from the above characterization results that the hollow heteroporous adsorption material can be successfully prepared by this method, and the hollow heteroporous adsorption material has good thermal stability and adsorption performance.
[0043] Example 3: HCOFs for the enrichment of phytochromes
[0044] Accurately weigh a certain amount of vegetable sample, soak it in 50 mL of a mixed solution of anhydrous ethanol and acetone (V:V=1:1) to extract chlorophyll from the sample, mix the HCOFs prepared in Example 2 with the buffer solution, add them to the extract, and achieve enrichment of the photosensitive pigment after shaking and adsorption.
[0045] 1-20 mg HCOFs were used to purify the same amount of vegetable sample extracts, and then the purified extracts were detected by UV-visible spectrophotometer. Figure 2 As shown in (A) and (B), the hollow heteroporous adsorption material almost completely removed the photosensitive pigment. Hac-NaAc, Tris-HCl, PBS and acetonitrile were used as buffers, and the results were shown in Figure 2As shown in (C), Tris-HCl has the best effect. This example also investigated the concentration and pH value of the buffer solution. The results are as follows Figure 2 As shown in (D) and (E), the effect is better when the concentration is 15-25mM and the pH value is 5-7.
[0046] After adsorption, HCOFs were added with eluent, ultrasonicated for 10 min, and then centrifuged to measure the pigment concentration in the supernatant. Ethanol, methanol, acetonitrile, acetone and DMF were used as eluents, and the elution effects were as follows: Figure 2 As shown in (F), acetone elution has the best effect. The elution efficiency is as follows: Figure 2 (G) shown.
[0047] Prepare spinach extract, place 1 mg / mL HCOFs and 1 mg / mL original COFs in spinach extract, shake and adsorb for different treatment time, then collect the lower layer solution by centrifugation, and detect the pigment of spinach extract. The results are as follows: Figure 3 As shown in the figure, HCOFs can basically complete the pigment adsorption after 5 seconds, COFs can basically complete the pigment adsorption after 30 seconds, and the adsorption rate of HCOFs is faster. This shows that the prepared hollow heteroporous adsorption material has efficient adsorption performance for the target.
[0048] Example 4: HCOFs for non-targeted screening of chemical hazards
[0049] Prepare vegetable sample extract, place HCOFs prepared in Example 2 in the extract, shake and adsorb, and then centrifuge to collect the lower layer solution. Combined with liquid chromatography-tandem mass spectrometry, non-targeted screening of chemical hazards can be performed.
[0050] Example 5: Repeatability study of hollow heteroporous materials
[0051] 5.0 mg of HCOF obtained in Example 1 was eluted with 5 mL of acetone. Ultrasonication was performed for 20 min until no adsorbed target was detected in the supernatant. The thoroughly washed material was placed in a vacuum oven and dried overnight at 40°C. The dried material was subjected to the same adsorption-elution-analysis steps as before, and the average value of three replicates was determined. This was repeated 20 times, and the recovery rate of the target was compared each time. The results are shown in Figure 4 As shown, the prepared hollow heteroporous adsorption material has good reusability and is suitable for the application of actual samples.
[0052] The embodiments of the present invention are described in detail above, but the contents described are only preferred embodiments of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.
Claims
1. A method for preparing a hollow heteroporous adsorption material, characterized in that: ETTA and BPDA were dissolved in acetonitrile, acetic acid was added after dispersion, and a closed reaction was performed at 120°C to obtain a composite heteroporous covalent organic framework material COFs.
2. The method for preparing the hollow heteroporous adsorption material according to claim 1, characterized in that: The amino-modified nanoparticles were dissolved in acetonitrile together with ETTA and BPDA. After the reaction in an autoclave, the resulting product was treated with hydrofluoric acid to remove the template, thereby obtaining a hollow heteroporous covalent organic framework material HCOFs.
3. The method for preparing the hollow heteroporous adsorption material according to claim 2, characterized in that: Ammonia water is added to a mixture of anhydrous ethanol and high-purity water, tetraethyl orthosilicate is added at 40° C., and 3-aminopropyltriethoxysilane is added and stirred to obtain amino-modified nanoparticles SiO2-NH2.
4. The method for preparing the hollow heteroporous adsorption material according to any one of claims 1 to 3, characterized in that: The specific preparation method is as follows: Step 1: Add ammonia water to a mixture of anhydrous ethanol and high-purity water, add tetraethyl orthosilicate at 40°C, and then add 3-aminopropyltriethoxysilane and stir to obtain amino-modified nanoparticles SiO2-NH2; Step 2: Dissolve SiO2-NH2, ETTA and BPDA in acetonitrile, disperse them evenly and then slowly add 6M acetic acid, place them in a reactor, and react at 120°C to obtain a composite heteroporous covalent organic framework material SiO2-NH2@COFs; Step 3: Treat SiO2-NH2@COFs with HF to obtain hollow heteroporous covalent organic framework material HCOFs.
5. The method for preparing the hollow heteroporous adsorption material according to claim 4, characterized in that: The ratio of water to ammonia is 1:
10.
6. The hollow isoporous adsorbent material prepared by the method for preparing the hollow isoporous adsorbent material according to any one of claims 1 to 5.
7. Use of the hollow heteroporous adsorption material according to claim 6 in food testing and food contaminant removal.
8. The use according to claim 7, characterized in that: HCOF is placed in the target solution and the interfering matrix in the sample is enriched by oscillation adsorption.
9. The use according to claim 7 or 8, characterized in that: Adding buffer and HCOFs to the target solution, the buffer being Tris-HCl; The adsorbed HCOFs are eluted by an eluent, which is acetone; the eluted HCOFs can be used again for adsorption or enrichment of interfering matrices.