A method for preparing an adsorbent that efficiently adsorbs aflatoxin M1 from sheep milk.

Abstract

This invention discloses a method for preparing an adsorbent that efficiently adsorbs aflatoxin M1 (AFM1) from goat milk. The method includes dispersing PCN-777 in ultrapure water and ultrasonically treating it to obtain a PCN-777 suspension; adding a ZnO nanoparticle colloidal solution to the PCN-777 suspension; stirring the resulting mixture at room temperature; washing the precipitate with methanol; and drying it in a vacuum oven to obtain the adsorbent. This invention successfully prepares an economical and efficient adsorbent material, ZnO@PCN-777, with good adsorption performance for the removal of AFM1 from goat milk. In real-world goat milk applications, ZnO@PCN-777 achieves an AFM1 removal efficiency of over 93%, and the adsorption process does not cause any changes in the quality of the goat milk. Furthermore, it exhibits good stability and reusability, is resistant to high temperatures and acids / alkalis, and can quickly restore its adsorption capacity after the adsorbed substance is removed, thus enabling recycling.

Description

Technical Field

[0001] This invention belongs to the field of detection technology, specifically relating to a method for preparing an adsorbent that efficiently adsorbs aflatoxin M1 from sheep milk. Background Technology

[0002] Aflatoxin is mainly produced by Aspergillus flavus and Aspergillus parasiticus through polyketide synthesis. It is hepatotoxic and classified as a Group 1 carcinogen by the World Health Organization. When feed is contaminated with aflatoxin B1, it metabolizes into aflatoxin M1 (AFM1) after being consumed by animals. These metabolites can be found in milk, eggs, urine, and meat, most commonly in milk and dairy products. Long-term consumption of contaminated dairy products can lead to poisoning, carcinogenesis, mutagenesis, and teratogenicity. Although scientists have long been dedicated to researching technologies for the prevention and degradation of aflatoxin in dairy products, a cost-effective and large-scale solution to contamination remains lacking. Therefore, to ensure food safety and protect human health, establishing an efficient method for removing AFM1 from milk is imperative.

[0003] Common AFM1 removal technologies in milk mainly fall into three categories: biodegradation, physicochemical techniques, and adsorption. While biodegradation offers advantages such as energy efficiency and environmental friendliness, its use in large-scale industrial production is limited due to the complexity and unknown nature of metabolites and harsh operating conditions. Physical and chemical techniques are more practical methods for AFM1 detoxification in milk. However, chemical methods easily lead to solvent residues, affecting the nutritional components of milk. Physical detoxification strategies for AFM1 in milk can be broadly categorized into irradiation detoxification and adsorption detoxification. Ultraviolet radiation, gamma ray irradiation, and microwave treatment are commonly used methods for reducing AFM1 in milk. Although irradiation methods are well-suited for large-scale use, these methods are typically time-consuming, and radiation may damage healthy components in milk. Adsorption methods offer advantages such as simple operation, high efficiency, low cost, and low toxicity, making them a more ideal approach. Therefore, adsorption methods, which remove toxins using various adsorbents, are simple to operate, highly efficient, low-cost, and have low toxicity, representing a promising direction.

[0004] Currently available AFM1 adsorbents mainly include clay, activated carbon, organic polymers, and biomaterials. Clay and activated carbon are inexpensive, but their adsorption capacity and removal efficiency are not ideal, and they are rarely used in complex matrices. Furthermore, they require larger quantities of adsorbent during detoxification, which may lead to the loss of nutrients in the milk due to adsorption. Molecularly imprinted polymers (MIPs) have been found to selectively adsorb AFM1. However, since these organic polymers are synthesized using AFM1 as a molecular template through polymerization, the use of MIP adsorbents during adsorption may contaminate the milk.

[0005] Therefore, it is urgent to develop new adsorbents that are efficient, green, safe, practical and economical. Summary of the Invention

[0006] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0007] In view of the problems existing in the above and / or prior art, the present invention is proposed.

[0008] Therefore, the purpose of this invention is to overcome the shortcomings of the prior art and provide a method for preparing an adsorbent that efficiently adsorbs aflatoxin M1 from sheep milk.

[0009] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for preparing an adsorbent for efficiently adsorbing aflatoxin M1 in goat milk, comprising,

[0010] 2,4,6-tris(4-carboxyphenyl)-aniline and zirconium oxychloride octahydrate were dissolved in a solvent, dissolved by sonication, and then trifluoroacetic acid was added. The mixture was heated to react, cooled to room temperature, centrifuged, washed, and dried to obtain PCN-777 white powder.

[0011] Slowly pour sodium citrate into heated deionized water and stir until completely dissolved. Add zinc nitrate and stir at 60-80°C for 20-30 minutes. After cooling to room temperature, a ZnO nanoparticle colloidal solution can be obtained.

[0012] PCN-777 was dispersed in ultrapure water and ultrasonically treated to obtain a PCN-777 suspension.

[0013] A ZnO nanoparticle colloidal solution was added to the PCN-777 suspension, and the resulting mixture was stirred at room temperature. The precipitate was washed with methanol and dried in a vacuum oven to obtain the adsorbent.

[0014] In a preferred embodiment of the preparation method described in this invention, 2,4,6-tris(4-carboxyphenyl)-aniline and zirconium oxychloride octahydrate are dissolved in a solvent, wherein the ratio of 2,4,6-tris(4-carboxyphenyl)-aniline to zirconium oxychloride octahydrate is 40-60 mg: 150-200 mg, and the solvent includes diethylformamide.

[0015] In a preferred embodiment of the preparation method described in this invention, the ratio of 2,4,6-tris(4-carboxyphenyl)-aniline to solvent is 60 mg: 8-12 mL.

[0016] In a preferred embodiment of the preparation method described in this invention, the heating reaction is carried out at a temperature of 100–120°C for 10–12 hours.

[0017] As a preferred embodiment of the preparation method described in this invention, the centrifugation, washing, and drying processes yield PCN-777 white powder, wherein the centrifugation speed is 8000 rpm, the centrifugation time is 6 minutes, the washing includes washing with DMF 2 to 3 times, and the drying temperature is 60 to 80°C.

[0018] In a preferred embodiment of the preparation method described in this invention, PCN-777 is dispersed in ultrapure water, wherein the ratio of PCN-777 to ultrapure water is 100 mg: 100 mL.

[0019] In a preferred embodiment of the preparation method described in this invention, ZnO nanoparticle colloidal solution is added to the PCN-777 suspension, wherein the volume ratio of the PCN-777 suspension to the ZnO nanoparticle colloidal solution is 1:1.

[0020] Another objective of this invention is to overcome the shortcomings of the prior art and provide an adsorbent prepared by a specific method.

[0021] Another objective of this invention is to overcome the shortcomings of the prior art and provide an application of an adsorbent in adsorbing aflatoxin M1 in sheep milk.

[0022] Beneficial effects of this invention:

[0023] This invention successfully prepared an economical and efficient adsorbent material, ZnO@PCN-777, with excellent adsorption performance for the removal of AFM1 from goat milk. In real-world goat milk applications, ZnO@PCN-777 achieved an AFM1 removal efficiency of over 93%, and the adsorption process did not alter the quality of the goat milk. Furthermore, it exhibits good stability and reusability, is resistant to high temperatures and acids / alkalis, and quickly restores its adsorption capacity after the adsorbed substances are removed, thus enabling recycling. Therefore, ZnO@PCN-777, as a novel adsorbent with good stability and biocompatibility, holds promise for application in the dairy industry for the removal of AFM1 contamination. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0025] Figure 1 This is a schematic diagram illustrating the manufacturing principle of the adsorbent in an embodiment of the present invention.

[0026] Figure 2 This is a graph showing the effect of adsorbent dosage on adsorption effect in embodiments of the present invention.

[0027] Figure 3 This is a graph showing the effect of adsorption time on the adsorption effect in an embodiment of the present invention.

[0028] Figure 4 This is a diagram illustrating the effect of the solvent on the adsorption effect in an embodiment of the present invention.

[0029] Figure 5 This is a graph showing the effect of the number of adsorbent repetitions on the adsorption effect in an embodiment of the present invention.

[0030] Figure 6 This is a pseudo-first-order kinetic model diagram of AFM1 adsorption in an embodiment of the present invention.

[0031] Figure 7 This is a pseudo-second-order kinetic model diagram of AFM1 adsorption in an embodiment of the present invention.

[0032] Figure 8 This is a Langmuir model diagram of AFM1 adsorption in an embodiment of the present invention.

[0033] Figure 9 This is a Freundlich model diagram of AFM1 adsorption in an embodiment of the present invention.

[0034] Figure 10 This is a comparative graph showing the adsorption effects of three materials in the embodiments of the present invention.

[0035] Figure 11 This is a comparative graph showing the adsorption properties of different toxins in the embodiments of the present invention. Detailed Implementation

[0036] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0037] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0038] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0039] Experimental materials used in this invention:

[0040] All chemicals and reagents are of analytical grade or higher; zirconium oxychloride octahydrate (ZrOCl2·8H2O), 2,4,6-tris(4-carboxyphenyl)-aniline (TATB), trichloroacetic acid, dimethylformamide (DMF), diethylformamide (DEF), methanol, ethanol, acetonitrile, ethyl acetate, sodium citrate solution, Zn(NO3)2·6H2O, and AFM1 standard solution prepared separately with methanol and stored at 4°C before use.

[0041] Preparation of the standard solution in this invention:

[0042] AFM1 standard solutions with concentrations of 2, 1.5, 1.0, 0.5, 0.3, and 0.1 μg / mL were prepared by diluting a 10 μg / mL AFM1 solution with methanol.

[0043] Example 1

[0044] Synthesis of MOF material PCN-777:

[0045] (1) First, dissolve TATB (60mg) and ZrOCl2·8H2O (200mg) in DEF (12ml), sonicate to dissolve, and then add 0.6ml of trifluoroacetic acid;

[0046] The mixture was then heated at 120°C for 12 hours;

[0047] After the mixture was cooled to room temperature, it was centrifuged at 8000 rpm for 6 minutes and washed twice with DMF.

[0048] Finally, after drying in an oven at 60°C, PCN-777 white powder was obtained.

[0049] (2) Synthesis of ZnO nanoparticles:

[0050] Add 300mL of ultrapure water to a beaker and heat to 60℃. Slowly pour in 0.075g of sodium citrate and stir until completely dissolved. Then add 0.05g of zinc nitrate to the beaker and stir at 80℃ for 30 minutes. After cooling to room temperature, ZnO nanoparticles can be obtained.

[0051] (3) Synthesis of adsorbent ZnO@PCN-777:

[0052] First, disperse 100 mg of PCN-777 in 100 ml of ultrapure water;

[0053] The mixture was sonicated for 5 minutes to obtain a PCN-777 suspension.

[0054] Next, 100 mL of the obtained ZnO nanoparticle colloidal solution was added, and the resulting mixture was stirred at room temperature for 2 hours.

[0055] Finally, the obtained precipitate was washed with methanol and dried in a vacuum oven. See the schematic diagram of the adsorbent manufacturing process. Figure 1 .

[0056] (4) Add 1.5 mg of adsorbent to 2 mL of AFM1 standard solutions of different concentrations. Then place the mixed solution on a shaker at 110 rpm to adsorb AFM1.

[0057] After 40 minutes, the adsorbent was separated by centrifugation, and the supernatant was used to determine the concentration of AFM1.

[0058] The adsorbent was desorbed using 1 mL of acetonitrile for 1 h, and the supernatant was collected by centrifugation for analysis. The adsorption capacity of ZnO@PCN-777 for AFM1 can be calculated using the following formula:

[0059]

[0060]

[0061] Where Qt (mg / g) is the adsorption capacity of ZnO@PCN-777, C0 (mg / L) and Ct (mg / L) are the initial and residual amounts of AFM1 in the supernatant at 0 min and t time, respectively, V (L) is the total volume of the adsorption solution, m is the amount of ZnO@PCN-777 added (mg), and W (%) is the removal efficiency of ZnO@PCN-777 for AFM1.

[0062] (5) Condition Optimization

[0063] The removal efficiency of AFM1 increased with increasing adsorbent dosage because the number of adsorption sites increased with increasing ZnO@PCN-777 content. To screen the optimal adsorbent dosage, different dosages of ZnO@PCN-777 were added to 2 mL of 0.1 mg / L AFM1 solution, and the supernatant was collected after centrifugation after 1 hour to detect the residual AFM1 concentration. The results are as follows: Figure 2 As shown, when the adsorbent dosage is 0.075% (w / w), the AFM1 removal rate can reach over 94%. Therefore, from an economic and practical perspective, 0.075% (w / w) is selected as the optimal adsorbent dosage.

[0064] Optimizing the adsorption time is crucial during the removal process, as sufficient adsorption time can maximize the removal of AFM1. 0.075% (w / w) ZnO@PCN-777 was added to 2 mL of a 0.1 mg / L AFM1 solution, and the adsorption equilibrium time was determined by detecting the residual AFM1 concentration in the supernatant at different time points. Results are as follows... Figure 3 As shown, the AFM1 removal rate increased significantly in the first 10 minutes, but after 40 minutes, the adsorption effect hardly changed with the extension of time. Therefore, 40 minutes was selected as the optimal adsorption time.

[0065] A suitable desorption solvent can effectively elute AFM1 from the adsorbent within a certain time. This is beneficial for evaluating the adsorption performance of the adsorbent and for the qualitative and quantitative detection of the target analyte AFM1. Therefore, different types of eluents were selected to investigate their desorption effects on AFM1. Figure 4 As shown, under the same conditions, when using acetonitrile, ethanol, methanol, and ethyl acetate solutions as desorption agents, acetonitrile exhibits the largest peak area, indicating that acetonitrile has the best desorption effect. Therefore, acetonitrile was chosen for further research.

[0066] The reusability of ZnO@PCN-777 was evaluated through repeated experiments. The adsorbent was washed three times by centrifugation with methanol and ultrapure water before each cycle and dried in a vacuum oven. The results showed that after 15 adsorption-desorption cycles, the removal rate of AFM1 was still greater than 85%. Figure 5 Therefore, the prepared ZnO@PCN-777 exhibits good durability and is a highly adsorbent material.

[0067] Example 2

[0068] (1) Adsorption kinetics:

[0069] This study uses pseudo-first-order and pseudo-second-order kinetic models to evaluate the adsorption mechanism of AFM1 in ZnO@PCN-777 nanocomposite materials. The pseudo-first-order kinetic model is expressed as Equation (1), and the pseudo-second-order kinetic model is expressed as Equation (2). The adsorption kinetics are studied by the curve of the adsorption amount changing with time.

[0070] like Figure 6 and Figure 7 As shown, adsorption occurs rapidly within the first 10 minutes, and after 40 minutes, the curves show a basically consistent trend. Therefore, 40 minutes is the equilibrium adsorption time.

[0071] ln(Q e -Q t )=lnQ e -K1t (1)

[0072]

[0073] Where K1 (1 / min) and K2 (g / mg·min) are pseudo-first-order and pseudo-second-order rate constants, respectively. Qe and Qt are the adsorption amounts (mg / g) of the adsorbent at equilibrium and time t, respectively, and Ce is the residual amount of AFM1 in the supernatant (mg / L). By comparing the magnitudes of the two simulation determination coefficients R², the adsorption results of this adsorbent in the standard solution are evaluated to determine which kinetic model conforms to.

[0074] The results of the adsorption kinetics fitting are shown in Table 1.

[0075] Table 1

[0076]

[0077] In this experiment, based on the simulation's coefficient of determination R², the pseudo-second-order kinetic model showed better fitting results than the pseudo-first-order kinetic model in standard solutions of different concentrations. Furthermore, the equilibrium adsorption amounts obtained by the pseudo-second-order kinetic model were all larger than those obtained by the pseudo-first-order kinetic model. This indicates that the pseudo-second-order kinetic model can better describe the adsorption kinetics of AFM1 on ZnO@PCN-777.

[0078] Generally, the adsorption process in pseudo-first-order models is mainly based on physical interactions, while pseudo-second-order models consider the entire adsorption process to rely primarily on chemisorption. Therefore, the adsorption of AFM1 by ZnO@PCN-777 is mainly chemisorption. The hydrophilic sites of the adsorbent can form adsorption or bonding forces with the fungal toxin. Through the redistribution or exchange of electrons, AFM1 is adsorbed from the solution and fixed on the adsorbent, thus achieving the removal and purification of the toxin.

[0079] (2) Adsorption thermodynamics

[0080] Adsorption isotherms provide important information about the relationship between the concentration of AFM1 in aqueous solution and the equilibrium adsorption capacity of ZnO@PCN-777. Depending on the properties of the adsorbent and the type of interaction, adsorption isotherms follow different mathematical models. This paper uses the Langmuir model and the Freundlich model to describe the adsorption isotherms. The Langmuir model is given by equation (3), and the Freundlich model by equation (4).

[0081]

[0082]

[0083] Where Qm is the saturated adsorption capacity (mg / g), KL is the Langmuir constant (L / mg), KF is the Freundlich adsorption constant (mg / g), and n is a parameter related to the interaction strength between the adsorbent molecule and the adsorbent surface, whose value is always greater than 1.

[0084] Figure 8 and Figure 9 The adsorption isotherm of AFM1 by ZnO@PCN-777 nanocomposite was fitted using the Langmuir and Freundlich models. By comparing different temperatures, it was found that the adsorption capacity of the adsorbent increased with increasing temperature. This shows that the higher the temperature, the stronger the adsorption capacity of the adsorbent for AFM1.

[0085] Table 2 shows the parameter results obtained by fitting the Langmuir and Freundlich models.

[0086]

[0087] As shown in Table 2, the correlation coefficients of the two models at different temperatures all reached above 0.9, with the Freundlich model showing a higher correlation coefficient than the Langmuir model. This indicates that the Freundlich model better fits the adsorption isotherm of AFM1 on the ZnO@PCN-777 nanocomposite than the Langmuir model, suggesting that the isothermal adsorption process in this experiment is more consistent with the Freundlich model. This indicates that the adsorption process is a non-ideal adsorption on a non-uniform surface, possibly involving multilayer adsorption, with non-specific adsorption being the dominant process. As the temperature increases, the value of 1 / n gradually increases, indicating that the adsorption force between ZnO@PCN-777 and AFM1 will be stronger, making it difficult for AFM1 to detach from the adsorbent during centrifugation.

[0088] Example 3

[0089] Comparison of adsorption effects of ZnO@PCN-777:

[0090] To evaluate the AFM1 removal effect of ZnO@PCN-777 nanocomposite before and after synthesis, 0.075% (w / w) of PCN-777, ZnO, and ZnO@PCN-777 were added to 2 mL of 0.1 mg / L AFM1 solution at room temperature. After 1 h of adsorption, the adsorption effect of the three materials was observed by detecting the concentration of residual AFM1 in the supernatant.

[0091] The results are as follows Figure 10As shown, the removal efficiency of PCN-777 and ZnO for AFM1 is below 80%, which is not as good as the adsorption effect of the combined material. This is mainly because the combination of the two materials increases the adsorption specific surface area, thereby providing more adsorption sites, allowing more AFM1 to come into contact with the adsorbent, increasing the contact time and diffusion path between AFM1 and the adsorbent, and thus enhancing the adsorption effect.

[0092] Example 4

[0093] Broad spectrum research:

[0094] To evaluate the adsorption capacity of ZnO@PCN-777 nanocomposite materials on different fungal toxins, 0.075% (w / w) of adsorbent was added to 2 mL of solutions of different types of toxins (AFM1, AFB1, AFB2 and OTA) at room temperature. After 2 h of adsorption, the adsorption effect of the adsorbent was observed by detecting the concentration of residual toxins in the supernatant.

[0095] The results are as follows Figure 11 As shown, the ZnO@PCN-777 nanocomposite material exhibits significant adsorption effects on all four toxins mentioned above, with removal rates exceeding 90%. This is primarily because the π bonds or unsaturated bonds in the mycotoxins can undergo electrophilic addition reactions with the electrophilic centers in the adsorbent, forming covalent bonds. Secondly, PCN-777 possesses large mesoporous cages with high porosity; the mesoporous molecular sieve generates strong capillary forces, accelerating the adsorption process. Furthermore, the terminal hydroxyl groups can form hydrogen bonds with hydrogen bond donors or acceptors in the mycotoxins. These chemical reactions lead to a strong bond between the mycotoxins and the adsorbent, thereby effectively removing or reducing the concentration of mycotoxins.

[0096] Example 5

[0097] Evaluation of the adsorption effect of ZnO@PCN-777 on AFM1 in goat milk:

[0098] To evaluate the effectiveness of ZnO@PCN-777 in practical applications, 0.05, 0.1, and 0.2 μg of AFM1, and 0.025% and 0.05% of adsorbent (w / w) were added to goat milk samples to study the adsorption effect of ZnO@PCN-777 on AFM1 in goat milk. Adsorption was carried out at room temperature. After 2 h, the goat milk samples were centrifuged at 7000 rpm for 10 min, at which point three different phases were formed in the centrifuge tube.

[0099] The upper fat layer was discarded, and the intermediate aqueous phase was filtered through a 0.45 μm polyvinylidene fluoride ultrafiltration membrane and diluted 10 times with PBS solution before the concentration of AFM1 was measured. The results are shown in Table 3. After adsorption by ZnO@PCN-777, the residual AFM1 in the goat milk met the national standard (GB2761-2017) requirement, i.e., not exceeding 0.5 μg / Kg.

[0100] Table 3. Residual AFM1 concentration in goat milk after ZnO@PCN-777 adsorption (n=3)

[0101]

[0102]

[0103] Considering the impact of ZnO@PCN-777 on the quality of goat milk, the physicochemical properties of goat milk, such as fat content, protein content, lactose content, pH, and acidity, were measured after the adsorbent was added. The results are shown in Table 4. No significant reduction in the nutrients of goat milk was detected, which proves that the ZnO@PCN-777 nanocomposite material has no obvious adsorption tendency for substances such as protein, lactose, and fat.

[0104] Table 4. Changes in the physicochemical properties of goat milk after ZnO@PCN-777 adsorption (n=3)

[0105]

[0106] Metal-organic frameworks (MOFs) are a class of porous crystalline materials composed of metal ions and clusters combined with organic bridging agents and ligands. The excellent properties of MOFs, including tunable pore size, large specific surface area, high porosity, and high stability, make them the most advanced form of adsorbent in various pollutant removal applications, and they can be used to remove mycotoxins from milk. ZnO nanoparticles possess a large specific surface area, enabling them to adsorb harmful substances such as heavy metals, organic matter, and dyes dissolved in water or gases, thereby removing them from the environment. They exhibit good stability and reusability, are resistant to high temperatures and acids / alkalis, and can quickly restore their adsorption capacity after the adsorbed substances are removed, thus achieving recycling. Furthermore, the carbonyl group in the aflatoxin structure possesses lone pairs of electrons, readily interacting with positively charged metal centers, thereby promoting the adsorption process.

[0107] This invention successfully prepared a safe, green adsorbent material, ZnO@PCN-777, with excellent adsorption performance for the removal of AFM1 from goat milk. The effects of adsorption parameters such as adsorbent dosage, adsorption time, eluent type, and reusability on the adsorption process were investigated, and the optimal conditions for adsorbent use were determined. Adsorption kinetics and thermodynamic studies showed that the adsorption behavior of AFM1 in ZnO@PCN-777 can be described by a pseudo-second-order kinetic model and a Freundlich model. Furthermore, in real-world goat milk applications, ZnO@PCN-777 achieved a AFM1 removal efficiency of over 93%, and the adsorption process did not cause any changes in the quality of the goat milk.

[0108] Therefore, ZnO@PCN-777, as a novel adsorbent, has good stability and biocompatibility. It also has good stability and reusability, and is resistant to high temperatures and acids and alkalis. After the adsorbed substances are removed, the adsorption capacity of the particles can be quickly restored, thus achieving recycling. It is expected to be applied to the dairy industry to remove AFM1 pollution.

[0109] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the present invention.

Claims

1. The application of ZnO@PCN-777 in adsorbing aflatoxin M1 in goat milk, characterized in that: The preparation method of the ZnO@PCN-777 includes, 2,4,6-tris(4-carboxyphenyl)-aniline and zirconium oxychloride octahydrate were dissolved in a solvent, dissolved by sonication, and then trifluoroacetic acid was added. The mixture was heated to react, cooled to room temperature, centrifuged, washed, and dried to obtain PCN-777 white powder. Slowly pour sodium citrate into heated deionized water and stir until completely dissolved. Add zinc nitrate and stir at 60-80°C for 20-30 minutes. After cooling to room temperature, a ZnO nanoparticle colloidal solution can be obtained. PCN-777 was dispersed in ultrapure water and ultrasonically treated to obtain a PCN-777 suspension. A ZnO nanoparticle colloidal solution was added to the PCN-777 suspension, and the resulting mixture was stirred at room temperature. The precipitate was washed with methanol and dried in a vacuum oven to obtain ZnO@PCN-777, wherein the volume ratio of the PCN-777 suspension to the ZnO nanoparticle colloidal solution was 1:

1.

2. The application as described in claim 1, characterized in that: The ratio of 2,4,6-tris(4-carboxyphenyl)-aniline to zirconium oxychloride octahydrate is 40~60 mg: 150~200 mg, and the solvent is diethylformamide.

3. The application as described in claim 1 or 2, characterized in that: The ratio of 2,4,6-tris(4-carboxyphenyl)-aniline to solvent is 60 mg: 8~12 mL.

4. The application as described in claim 1, characterized in that: The heating reaction temperature is 100~120℃, and the heating time is 10~12 hours.

5. The application as described in claim 1, characterized in that: The centrifugation speed is 8000 rpm, the centrifugation time is 6 minutes, the washing is performed with DMF 2-3 times, and the drying temperature is 60-80℃.

6. The application as described in claim 1, characterized in that: The ratio of PCN-777 to ultrapure water is 100 mg: 100 mL.

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