Magnetic metal organic framework material for mycotoxin detection and adsorption as well as preparation method and application of magnetic metal organic framework material

Abstract

The invention discloses a magnetic metal organic framework material for mycotoxin detection and adsorption as well as a preparation method and application of the magnetic metal organic framework material, and belongs to the technical field of detection and adsorption. The magnetic metal organic framework material is prepared by the following method: dissolving AlCl3. 6H2O in water, then adding 2-amino-terephthalic acid, stirring, adding a magnetic mesoporous carbon material, and uniformly mixing; then adding a urea solution, carrying out ultrasonic treatment, and reacting at high temperature; and after the reaction is finished, cooling to room temperature, washing, centrifuging and drying to obtain the magnetic metal organic framework material. The magnetic metal organic framework material provided by the invention has better application in the field of adsorption and detection of fungaltoxin, especially detection and adsorption of aflatoxin B1, has the characteristics of high sensitivity, high selectivity, high adsorption capacity and the like, is easy to recycle, avoids material waste, and has better economic benefit and environmental friendliness.

Description

Technical Field

[0001] The present invention belongs to the technical field of detection and adsorption, and in particular relates to a magnetic metal organic framework material for mycotoxin detection and adsorption, and a preparation method and application thereof. Background Art

[0002] Mycotoxins are toxic metabolites produced by fungi and are widely found in crops, food and feed. Common mycotoxins include aflatoxins, ochratoxins, zearalenone, etc. Long-term intake of these toxins may lead to health problems such as food poisoning, liver cancer, and immune system damage. Mycotoxins have strong carcinogenicity, mutagenicity and immunotoxicity, posing a threat to human health. Therefore, accurate and efficient detection of mycotoxins in food and feed is an important task in food safety monitoring. Currently, many studies are focused on developing detection methods for mycotoxins in order to promptly detect and prevent the harm of toxins to human health.

[0003] Currently, the detection methods for mycotoxins usually use high performance liquid chromatography (HPLC), gas chromatography-mass spectrometry (GC-MS) and immunoassay, but these methods generally have the disadvantages of cumbersome operation, expensive instruments, long detection time and high detection cost. In addition, the sensitivity and selectivity of traditional detection methods sometimes cannot meet the needs of rapid food safety detection.

[0004] Metal-organic frameworks (MOFs) have attracted extensive attention from researchers in the field of adsorption of various pollutants, including organic dyes, heavy metals, drugs, and hazardous substances, due to their huge surface area, high porosity with variable pore sizes, flexibility, adaptability, and customized chemical functionality. Metal ions or clusters act as nodes in the MOF structure, and organic ligands act as connectors for coordination bonds between nodes. In addition, due to their outstanding properties, MOFs also have potential applications in catalysis, air filtration, chemical sensing, drug delivery, adsorption, energy storage, oxygen reduction reaction, noise reduction, molecular separation, and gas storage. The two main obstacles for MOFs to be used for pollutant removal are their instability in aqueous environments due to irreversible destruction of their porous structures caused by hydrolysis, and their long separation time after batch adsorption, which requires long centrifugation and separation. Therefore, it is necessary to develop new magnetic MOF materials to improve their adsorption selectivity for different mycotoxins, increase detection sensitivity, and further optimize the stability and reusability of their materials to meet the needs of practical applications. Summary of the invention

[0005] The invention provides a magnetic metal organic framework material for fungal toxin detection and adsorption. The material is a magnetic mesoporous carbon material in situ grafted with a MOF material.

[0006] The present invention provides a method for preparing the magnetic metal organic framework material, comprising the following steps:

[0007] AlCl3·6H2O is dissolved in water, and then 2-amino-terephthalic acid is added, stirred, and magnetic mesoporous carbon material is added and mixed evenly; then urea solution is added, ultrasonic treatment is performed, and the mixture is placed under high temperature for reaction; after the reaction is completed, the mixture is cooled to room temperature, washed, centrifuged, and dried to obtain a magnetic metal organic framework material.

[0008] In the above preparation method, each component is selected from the following parts:

[0009] 1-2 parts of AlCl3·6H2O, 25-35 parts of water, 1-2 parts of 2-amino-terephthalic acid, 0.5-1 part of magnetic mesoporous carbon material, and 5-15 parts of urea solution;

[0010] When the component is a solid component, the portion number represents grams; when the component is a liquid component, the portion number represents milliliters; in actual applications, the portion number can be enlarged or reduced in proportion to the portion number.

[0011] In a specific embodiment, the mass fractions of the components are as follows:

[0012] AlCl3·6H2O 1.448 parts, water 30 parts, 2-amino-terephthalic acid 1.088 parts, magnetic mesoporous carbon material 0.934 parts, urea solution 10 parts;

[0013] When the component is a solid component, the portion number represents grams; when the component is a liquid component, the portion number represents milliliters; in actual applications, the portion number can be enlarged or reduced in proportion to the portion number.

[0014] In the above preparation method, the concentration of the urea solution is selected from 5 to 6%, preferably 5.76%.

[0015] In the above preparation method, the high temperature reaction conditions are selected from: reacting at 140-160°C for 4.5-5.5h; preferably reacting at 150°C for 5h.

[0016] In the above preparation method, the ultrasonic treatment time is selected from 30 to 60 minutes, preferably 30 minutes.

[0017] In the above preparation method, the magnetic mesoporous carbon material is prepared by the following method:

[0018] Dissolve ammonium ferric oxalate in water, add pomegranate peel powder, stir evenly, react, and obtain an iron-based black-brown complex; carbonize the iron-based black-brown complex at high temperature, wash, and dry after carbonization to obtain a magnetic mesoporous carbon material.

[0019] In the above method for preparing the magnetic mesoporous carbon material, each component is selected from the following parts:

[0020] 17-18 parts of ammonium ferric oxalate, 45-55 parts of water, 11-12 parts of pomegranate peel powder;

[0021] When the component is a solid component, the portion number represents grams; when the component is a liquid component, the portion number represents milliliters; in actual applications, the portion number can be enlarged or reduced in proportion to the portion number.

[0022] In a specific embodiment, the mass fractions of the components are as follows:

[0023] 17.12 parts of ammonium ferric oxalate, 50 parts of water, 11.667 parts of pomegranate peel powder;

[0024] When the component is a solid component, the portion number represents grams; when the component is a liquid component, the portion number represents milliliters; in actual applications, the portion number can be enlarged or reduced in proportion to the portion number.

[0025] In the above-mentioned method for preparing magnetic mesoporous carbon material, the reaction conditions are selected from: reacting at 55-70° C. for 60-96 hours; preferably reacting at 60° C. for 72 hours.

[0026] In the above-mentioned method for preparing magnetic mesoporous carbon material, the carbonization conditions are selected from: carbonization at 600-700° C. and N 2 atmosphere for 2.5-3.5 h; preferably: carbonization at 650° C. and N 2 atmosphere for 3 h.

[0027] The present invention provides application of the magnetic metal organic framework material in adsorption and / or detection of fungal toxins.

[0028] In the present invention, the fungal toxin is aflatoxin B1.

[0029] In the present invention, the magnetic metal organic framework material is mixed with a sample containing aflatoxin B1 to achieve adsorption of aflatoxin B1. The detection of aflatoxin B1 can be achieved by the following method:

[0030] The magnetic metal organic framework material is dispersed in a phosphate buffer solution, and then the sample solution is added and mixed evenly, and the fluorescence intensity at 435nm is immediately measured under excitation at 310nm; if the fluorescence intensity after adding the sample is higher than the fluorescence intensity without adding the sample, it means that the sample contains aflatoxin B1; if the fluorescence intensity after adding the sample is not higher than the fluorescence intensity without adding the sample, it means that the sample does not contain aflatoxin B1.

[0031] The beneficial effects of the present invention are:

[0032] The present invention provides a magnetic metal organic framework material Al-MOFs / MPC, which has a rich pore structure, can simultaneously detect and adsorb aflatoxin B1, has a large adsorption capacity, and rapidly adsorbs toxins and is sensitive to detection. At the same time, the material is also magnetic, and can quickly recover MOF materials through magnetic separation, reduce reagent consumption, and simplify operation steps.

[0033] In summary, the Al-MOFs / MPC material provided by the present invention has good application in the field of adsorption and detection of fungal toxins, especially for the detection and adsorption of aflatoxin B1, and has the characteristics of high sensitivity, high selectivity and high adsorption capacity, and is easy to recycle, avoiding material waste, and has good economic benefits and environmental friendliness. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 are the SEM images, TEM images and element mapping images of each sample; wherein, a is the SEM image of the Al-MOFs sample, b is the SEM image of the Al-MOFs / MPC sample, c is the TEM image of the Al-MOFs sample, d is the TEM image of the Al-MOFs / MPC sample, and e is the element mapping image of the Al-MOFs / MPC sample;

[0035] Figure 2 XRD patterns of Al-MOFs, MPC and Al-MOFs / MPC;

[0036] Figure 3 FT-IR images of Al-MOFs, MPC and Al-MOFs / MPC;

[0037] Figure 4 TGA images of Al-MOFs, MPC and Al-MOFs / MPC;

[0038] Figure 5 N2 adsorption-desorption isotherms (left) and pore size distribution images (right) of Al-MOFs, MPC and Al-MOFs / MPC samples;

[0039] Figure 6 The adsorption amount of AFB1 on Al-MOFs / MPC varies with adsorption time (a), pseudo-first-order adsorption kinetics (b), pseudo-second-order adsorption kinetics (c), Weber-Moris intraparticle diffusion model (d), fitting lines of Langmuir model and Freundlich model (e), and fitting line of partition coefficient with temperature (f);

[0040] Figure 7UV-visible absorption and fluorescence spectra of the material (a), emission spectra of the material at different excitation wavelengths (b), fluorescence measurement of the material by adding different concentrations of AFB1 in sequence (c), relationship between fluorescence enhancement factor and AFB1 concentration (d-e), fluorescence intensity response of Al-MOFs / MPC to AFB1 and interfering substances in the absence of AFB1 (f);

[0041] Figure 8 Effect of pH on the adsorption capacity of AFB1 by Al-MOFs / MPC (a), reusability of Al-MOFs / MPC (b), XRD patterns of Al-MOFs / MPC before and after adsorption (c), and FT-IR patterns of Al-MOFs / MPC (d). DETAILED DESCRIPTION

[0042] Other materials used in the present invention, if not otherwise stated, can be obtained through commercial channels. Other terms used in the present invention, unless otherwise specified, generally have the meanings commonly understood by those of ordinary skill in the art. The present invention is further described in detail below in conjunction with specific examples and with reference to data. The following examples are only for illustrating the present invention, and are not intended to limit the scope of the present invention in any way.

[0043] Example 1

[0044] Preparation of magnetic metal organic framework material Al-MOFs / MPC, the steps are as follows:

[0045] Dissolve 1.448g AlCl3·6H2O in 30mL deionized water, stir continuously for 30min, add 1.088g 2-amino-terephthalic acid (NH2-BDC) under stirring, then add 0.934g magnetic mesoporous carbon material (MPC) under stirring, and mix thoroughly. Then, add 10mL urea solution (concentration of 5.76%, that is, 0.576g urea dissolved in 10mL deionized water) under ultrasonic conditions, after ultrasonication for 30min, transfer the mixture to a 100mL Tron-lined reactor and keep it at 150℃ for 5h. Then, cool naturally to room temperature. Wash with deionized water and centrifuge. Then disperse the solid in DMF, stir in the dark at room temperature for 24h, and centrifuge to remove DMF; then disperse the solid in methanol, stir in the dark at room temperature for 24h, and centrifuge to remove methanol to finally remove unreacted 2-amino-terephthalic acid. The product was vacuum dried at 50°C for 24 h to obtain the magnetic metal-organic framework material Al-MOFs / MPC.

[0046] The magnetic mesoporous carbon material (MPC) is prepared by the following method:

[0047] Dissolve 17.120g of ammonium ferric oxalate [(NH4)3Fe(C2O4)3·3H2O] in 50mL of water, add 11.667g of pomegranate peel powder and stir thoroughly. Place the mixture in an oven at 60°C for 72h. As the solvent gradually evaporates, the -COOH and -OH groups on the surface of the PG pores can easily coordinate with the absorbed iron ions. The obtained iron-based black-brown complex is heated to 650°C at a rate of 3°C / min in a tube furnace and carbonized for 3h under N2 atmosphere. Finally, it is soaked and washed with anhydrous ethanol and deionized water to remove unbound iron ions and organic impurities, and dried at 60°C for 24h to obtain a magnetic mesoporous carbon material.

[0048] Figure 1 The SEM images, TEM images and elemental mapping images of each sample are shown; among them, a is the SEM image of the Al-MOFs sample, b is the SEM image of the Al-MOFs / MPC sample, c is the TEM image of the Al-MOFs sample, d is the TEM image of the Al-MOFs / MPC sample, and e is the elemental mapping image of the Al-MOFs / MPC sample.

[0049] Depend on Figure 1 It can be seen that Al-MOFs presents a flake structure. According to the SEM and TEM of the Al-MOFs / MPC material, it can be seen that the mesoporous carbon is dispersed on the Al-MOFs. Figure e shows the elemental mapping of Al-MOFs / MPC. The uniform distribution of Al, N, O, C and Fe elements confirms that Al-MOFs has been successfully anchored on the MPC surface. This uniform distribution indicates that the composite of MPC and Al-MOFs is successful.

[0050] Figure 2 The XRD patterns of Al-MOFs, MPC and Al-MOFs / MPC are shown. Figure 2 It can be seen that Al-MOFs has obvious diffraction peaks mainly at 2θ of 8.8°, 10.5°, 15°, 17.5°, and 27.5°, and the corresponding crystal planes are (101)(200)(011)(202)(020). Al-MOFs / MPC has characteristic peaks of MPC and Al-MOFs, indicating the successful synthesis of Al-MOFs / MPC composites.

[0051] Figure 3 FT-IR images of Al-MOFs, MPC and Al-MOFs / MPC are shown. FT-IR is used to characterize the changes in the chemical bond structure of the materials. Figure 3 It can be seen that the original Al-MOFs and Al-MOFs / MPC have similar infrared peaks. -1 and 3379cm -1The band at 1578cm corresponds to the asymmetric stretching vibration of the NH bond, indicating the presence of NH2 groups after the coordination reaction. -1 and 1497cm -1 The two bands are attributed to 2-aminoterephthalic acid (NH2-BDC) and Al 3+ Asymmetric stretching vibration of the coordinated CO group. 3+ The symmetric stretching vibration of the coordinated CO group appears at 1437 cm -1 and 1397cm -1 .1258cm -1 The absorption band at 1062 cm -1 and 1003cm -1 The new energy band at is generated by the stretching vibration of the Al-O bond, which further indicates that the O atom of 2-aminoterephthalic acid (NH2-BDC) is bound to Al 3+ Together they form a metal organic framework. 1128.60cm -1 The peak at is the characteristic peak of MPC, which confirms the successful combination of MPC and Al-MOFs from another perspective.

[0052] Figure 4 The TGA images of Al-MOFs, MPC and Al-MOFs / MPC are shown. The thermal stability of the materials is investigated through TGA experiments. Figure 4 As shown in the figure, only a low proportion of mass loss was observed for MPC at temperatures below 100°C due to the evaporation of physically absorbed water. The second stage of weight loss occurred at 670°C with a weight loss rate of 15%. The weight loss stages of Al-MOFs and Al-MOFs / MPC are clearly divided into three stages. The mass loss in the first stage is usually due to the evaporation of adsorbed water or crystallization water. The weight loss in the second stage may be due to the loss of organic ligands; the third stage of weight loss at 670°C may be due to the formation of metal oxides and the complete decomposition of organic groups.

[0053] Figure 5 The N2 adsorption-desorption isotherms and pore size distribution images of Al-MOFs, MPC and Al-MOFs / MPC samples are shown. Figure 5 It can be seen that the specific surface areas of Al-MOFs, MPC and Al-MOFs / MPC are 163.980, 195.754 and 225.222 m 2 / g. After the introduction of MPC, the specific surface area of ​​the composite material is higher than that of the original MOF, indicating that the effective loading of MPC but the composite photocatalyst still maintains a high specific surface area, which can provide more active sites and is conducive to the adsorption reaction.

[0054] The above picture shows that after the MPC and Al-MOFs are composited, their specific surface area increases, and there are more active sites on the surface for adsorbed substances to bind to it. Therefore, increasing the specific surface area helps to improve the adsorption capacity, allowing AFB1 to have more contact with the material surface. An increase in specific surface area is usually accompanied by an increase in adsorption capacity. This is because more surface area can accommodate more adsorbed substances, allowing the unit mass of adsorbent material to adsorb more substances, thereby enhancing the overall adsorption performance of the adsorbent material. At the same time, after MPC is added, the composite material has magnetic properties, and the MOF material can be quickly recovered through magnetic separation.

[0055] 1. Adsorption test of aflatoxin B1

[0056] AFB1 solution was prepared by initially dissolving AFB1 powder in methanol. The solution was then diluted with deionized water to achieve the desired concentration. This method ensures uniform distribution of AFB1, making it suitable for subsequent applications or analysis. Take 10 mg of adsorbent and add 20 mL of solution containing AFB1, and shake it horizontally at 200 rpm in a constant temperature shaking box at room temperature and in the dark. Take out 500 μL at regular intervals, filter it through a 0.22 μm membrane filter, and analyze it by high performance liquid chromatography. The adsorption of AFB1 by the material is calculated by the following formula:

[0057] Q e =(C0-C t )·V / m

[0058] Where Q e (mg / g) represents the adsorption capacity at equilibrium, C0 (mg / L) and C t (mg / L) represent the initial concentration and equilibrium concentration of AFB1, respectively. V(L) represents the volume of AFB1 solution, and m(g) represents the mass of adsorbent. A concentration of 2.5 mg / L was used for adsorption kinetic studies at specified time intervals from 0 to 180 min. The effect of pH on the adsorption of AFB1 was evaluated by varying the pH value of the initial solution from 2 to 9. In the adsorption thermodynamic studies, the adsorption temperatures were controlled at 298 K, 308 K, and 318 K, respectively.

[0059] Test results such as Figure 6 As shown:

[0060] Figure 6 The adsorption curve of AFB1 by Al-MOFs / MPC versus adsorption time (a), pseudo-first-order adsorption kinetics (b), pseudo-second-order adsorption kinetics (c), Weber-Moris intraparticle diffusion model (d), fitting lines of Langmuir model and Freundlich model (e), and fitting line of isolation coefficient versus temperature (f) are shown.

[0061] R of the pseudo-second-order adsorption kinetic model 2 The value is higher than the R of the pseudo-first-order adsorption kinetic model. 2 The values ​​indicate that the pseudo-first-order adsorption kinetic model more accurately characterizes the adsorption behavior of AFB1. The results show that in addition to multilayer adsorption, the process is also accompanied by chemical adsorption. Chemical adsorption involves the formation of strong chemical bonds between the adsorbent molecules and the adsorbent surface. This means that in addition to the physical stratification of molecules, specific interactions also occur at the molecular level, which contributes to the overall stability and strength of adsorption.

[0062] The diffusion mechanism of AFB1 on Al-MOFs / MPC was investigated using the intraparticle diffusion model, and the rate-controlling step of AFB1 adsorption on Al-MOFs / MPC was identified. The adsorption process can be divided into two different stages. In the initial stage, the diffusion of AFB1 occurs during the migration of molecules to the surface of the adsorbent material. This indicates that there are sufficient and available adsorption sites in Al-MOFs / MPC. This can be attributed to the large surface area of ​​Al-MOFs / MPC, which enhances its adsorption capacity and promotes the diffusion process of AFB1 adsorption. The second stage involves further diffusion of AFB1 inside the adsorption system. Over time, the overall adsorption behavior begins to slow down and the adsorption rate decreases. In this stage, the main mechanism is intraparticle diffusion, that is, the adsorbate molecules penetrate deep into the pores of the material. However, over time, these sites are filled and the interaction between the remaining available sites and the AFB1 molecules decreases, resulting in a decrease in the overall adsorption rate.

[0063] In order to study the relationship between the adsorption amount of Al-MOFs / MPC and the equilibrium concentration of AFB1, the adsorption isotherm of Al-MOFs / MPC is given. In order to analyze the experimental data, the Langmuir model and the Freundlich model are used. The fitting results of these models are shown in Figure 6 a to 6c. The Freundlich model showed a significant correlation (R 2 >0.99), indicating that the adsorption can be fully described by the Freundlich model, indicating multilayer adsorption. The adsorption capacity of Al-MOFs / MPC can reach 19.761 mg / g, which has good removal potential.

[0064] Depend on Figure 6It can be seen from f that as the solution temperature increases, the adsorption amount gradually decreases, indicating that lower temperatures are conducive to the adsorption process. At different temperatures, the Gibbs free energy change (ΔG) is negative, indicating that the adsorption process is spontaneous. In any adsorption system, the larger the absolute value of ΔG, the greater the adsorption driving force. The absolute value of ΔG decreases with increasing temperature, indicating that the adsorption driving force decreases with increasing temperature. Both the enthalpy change (ΔH) and the entropy change (ΔS) are negative, indicating that the adsorption process is an exothermic process and the adsorption system tends to be ordered.

[0065] 2. Detection test of aflatoxin B1

[0066] 10 mg of Al-MOFs / MPC was dispersed in 10 mL of phosphate buffer solution (0.01 M, pH = 7.4). The obtained Al-MOFs / MPC test solution was diluted to a final concentration of 0.1 μg / mL. Then, 300 μL of AFB1 solutions of different concentrations (0, 0.05, 0.10, 0.25, 1, 2, 2.5, 5, 8, 15, 20, 25, 30, 40 and 50 μM) were mixed with 2.7 mL of Al-MOFs / MPC solution (0.1 μg / mL).

[0067] To evaluate the specificity of Al-MOFs / MPC for AFB1, three fungal toxins (including AFB2, OTA, and ZEN) were applied to the sensing system by a procedure similar to that for detecting AFB1.

[0068] In order to verify the anti-interference performance of Al-MOFs / MPC for AFB1 detection, the Na + , K + 、Zn 2+ 、Co 2+ , Ca 2+ and Al 3+ The interference of plasma and main active substances such as Cys, AA, and FR on the system. 5mM of the above ions and 0.1μg / mL Al MOFs / MPC were introduced into the system. ex =310 nm, and the fluorescence intensity of the obtained samples was collected at 435 nm.

[0069] Test results such as Figure 7 As shown:

[0070] Figure 7 The UV-visible absorption spectrum and fluorescence spectrum of the material (a), the emission spectrum of the material at different excitation wavelengths (b), the fluorescence measurement of the material by adding different concentrations of AFB1 in sequence (c), the relationship between the fluorescence enhancement factor and the AFB1 concentration (d~e), and the fluorescence intensity response of Al-MOFs / MPC to AFB1 and interfering substances in the absence of AFB1 (f) are shown.

[0071] Depend on Figure 7 a It can be seen that when the excitation wavelength is 310nm, Al-MOFs / MPC has a strong fluorescence emission at 435nm. It is worth noting that the optimal excitation wavelength of Al-MOFs / MPC is 310nm. The results show that with the increase of AFB1 concentration, the fluorescence emission intensity of Al-MOFs / MPC solution at 435nm increases. The fluorescence intensity at 435nm when AFB1 is not added is F0, and the fluorescence intensity of AFB1 with different concentration gradients is F.

[0072] Through linear fitting, the results show that the relative fluorescence intensity and AFB1 concentration show a good linear relationship. The fitting results are as follows: Figure 7 d and Figure 7 As shown in Figure e, the fluorescence emission intensity of Al-MOFs / MPC at 435 nm shows a good linear relationship in the concentration range of 0-30 μM. The linear equation derived from this relationship is y=0.05835x+1.12827, and the correlation coefficient R 2 is 0.998.

[0073] In order to evaluate the specificity of Al-MOFs / MPC for AFB1, three fungal toxins, AFB2, OTA and ZEN, were used for detection. In order to verify the anti-interference performance of Al-MOFs / MPC for AFB1 detection, the Na + , K + 、Zn 2+ 、Co 2+ , Ca 2+ and Al 3+ The interference effects of ions and main active substances Cys, FR, GL, Gly, Lys, AA and GA on the system. The above ions were introduced into the system at a concentration of 0.1 μg / mL at 5 mM. ex =310nm, and the fluorescence intensity of the obtained sample was collected at 435nm. As shown in the figure, it can be concluded that the detection of AFB1 is not interfered by the presence of metal ions.

[0074] 3. Recycling and Reusability of Al-MOFs / MPC

[0075] In order to explore the stability and reusability of Al-MOFs / MPC materials, five consecutive AFB1 adsorption experiments were carried out. In the cyclic experiment, the adsorbent was separated from the solution with a magnet, washed with methanol and ultrapure water, and re-added to the solution containing AFB1 for the next cycle. This was repeated five times to determine its adsorption capacity. The pH of the solution is a key factor affecting adsorption because it can change the surface properties and adsorption efficiency of the adsorbent. In order to investigate the effect of the initial pH of the solution on the adsorption of AFB1 by Al-MOFs / MPC, the initial pH of the solution was changed, and its adsorption capacity and adsorption efficiency were determined. In order to explore the reusability of the material, the adsorbent was separated from the solution with a magnet, washed with methanol and ultrapure water, and its XRD was measured after drying. The adsorbent was separated from the solution with a magnet, and its FT-IR was measured after drying.

[0076] Test results such as Figure 8 As shown:

[0077] Figure 8 The effect of pH on the adsorption capacity of AFB1 by Al-MOFs / MPC (a), the reusability of Al-MOFs / MPC (b), the XRD patterns of Al-MOFs / MPC before and after adsorption (c), and the FT-IR patterns of Al-MOFs / MPC (d) are shown.

[0078] The pH of the solution is a key factor affecting adsorption because it can change the surface properties and adsorption efficiency of the adsorbent. The effect of the initial pH of the solution on the adsorption of AFB1 by MOFs / MPC was investigated. Figure 8 As shown in a, the adsorption amount decreased with the decrease in solution pH. Under alkaline conditions, AFB1 may undergo hydrolysis, resulting in its partial or complete degradation. This reaction involves the breaking of chemical bonds in aflatoxin molecules and may result in less toxic or non-toxic products. After each adsorption cycle, the magnetic material was effectively separated from the solution using a magnet. In addition, the adsorbent was regenerated by alternating washing with deionized water and methanol, and the removal efficiency of AFB1 was measured to determine the reuse efficiency of the material. The adsorption capacity of the Al-MOFs / MPC material decreased by less than 10% relative to the initial adsorption capacity, indicating the reusability of the material and demonstrating its effectiveness in removing AFB1 from aqueous solutions.

[0079] The XRD spectra of Al-MOFs / MPC before and after adsorption of AFB1 are shown in Figure 2. Figure 8 c. The XRD spectrum after adsorption shows that several characteristic peaks of Al-MOFs / MPC are still visible, indicating that Al-MOFs / MPC has good reproducibility for the removal of AFB1.

[0080] FT-IR images of MOFs / MPC before and after adsorption Figure 8 As shown in d, before adsorption, 1666.71 cm -1 The absorption peak at 1687.15 cm -1 This is because the absorption peak before adsorption is consistent with the 1688 cm-1 peak in the FTIR spectrum of AFB1. -1 The absorption peaks at 992.60cm -1 The absorption peak intensity at 990.029 cm -1 The absorption peak at 983 cm-1 in the FTIR spectrum of AFB1 -1 The FTIR spectrum after adsorption is at 1239.656 cm -1 and 1311.862cm -1 , 754.842cm -1 A new absorption peak appeared at , which may correspond to the characteristic absorption peak of AFB1.

[0081] The above is only a preferred embodiment of the present invention, and does not limit the present invention in other forms. Any technician familiar with the profession may use the above disclosed technical content to change or modify it into an equivalent embodiment with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the technical solution of the present invention still belongs to the protection scope of the technical solution of the present invention.

Claims

1. A magnetic metal organic framework material for mycotoxin detection and adsorption, characterized in that: The material is a magnetic mesoporous carbon material in-situ grafted with a MOF material.

2. The method for preparing the magnetic metal organic framework material according to claim 1, characterized in that: The steps include: AlCl3·6H2O is dissolved in water, and then 2-amino-terephthalic acid is added, stirred, and magnetic mesoporous carbon material is added and mixed evenly; then urea solution is added, ultrasonic treatment is performed, and the mixture is placed under high temperature for reaction; after the reaction is completed, the mixture is cooled to room temperature, washed, centrifuged, and dried to obtain a magnetic metal organic framework material.

3. The preparation method according to claim 2, characterized in that: The ingredients are selected from the following quantities: 1 to 2 parts of AlCl3·6H2O, 25 to 35 parts of water, 1 to 2 parts of 2-amino-terephthalic acid, 0.5 to 1 part of magnetic mesoporous carbon material, and 5 to 15 parts of urea solution.

4. The preparation method according to claim 2, characterized in that: The concentration of the urea solution is selected from 5 to 6%; and / or the conditions of the high temperature reaction are selected from: reacting at 140 to 160° C. for 4.5 to 5.5 hours; and / or the time of the ultrasonic treatment is selected from 30 to 60 minutes.

5. The preparation method according to claim 2, characterized in that: The magnetic mesoporous carbon material is prepared by the following method: Dissolve ammonium ferric oxalate in water, add pomegranate peel powder, stir evenly, react, and obtain an iron-based black-brown complex; carbonize the iron-based black-brown complex at high temperature, wash, and dry after carbonization to obtain a magnetic mesoporous carbon material.

6. The preparation method according to claim 5, characterized in that: In the method for preparing the magnetic mesoporous carbon material, each component is selected from the following parts: 17-18 parts of ammonium ferric oxalate, 45-55 parts of water, 11-12 parts of pomegranate peel powder.

7. The preparation method according to claim 5, characterized in that: In the preparation method of the magnetic mesoporous carbon material, the reaction conditions are selected from: reacting at 55-70°C for 60-96 hours; and / or, the carbonization conditions are selected from: carbonizing at 600-700°C in a N2 atmosphere for 2.5-3.5 hours.

8. Use of the magnetic metal organic framework material according to claim 1 or the magnetic metal organic framework material prepared by the method according to any one of claims 2 to 7 in the adsorption and / or detection of fungal toxins.

9. The use according to claim 8, characterized in that: The fungal toxin is aflatoxin B1.

10. The use according to claim 8, characterized in that: The mycotoxin detection is carried out by the following method: The magnetic metal organic framework material is dispersed in a phosphate buffer solution, and then the sample solution is added and mixed evenly, and the fluorescence intensity at 435nm is immediately measured under 310nm excitation; if the fluorescence intensity after adding the sample is higher than the fluorescence intensity without adding the sample, it means that the sample contains fungal toxins; if the fluorescence intensity after adding the sample is not higher than the fluorescence intensity without adding the sample, it means that the sample does not contain fungal toxins.

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