A material for efficiently adsorbing and removing aflatoxin B1, a preparation method thereof, and application thereof

Abstract

This invention provides a material for the efficient adsorption and removal of aflatoxin B1, its preparation method, and its application. The material is a tannic acid-modified magnetic graphitic carbon nitride material. By modifying polyhydroxyl-rich tannic acid onto carbon nitride with nitrogen-rich functional groups, a tannic acid-modified magnetic graphitic carbon nitride nanocomposite material can be controllably prepared to adsorb and remove aflatoxin B1 from peanut oil. The preparation conditions, adsorption conditions, and material reproducibility were optimized, and a highly efficient aflatoxin B1 detoxification technology for peanut oil was constructed. The material is low-cost, environmentally friendly, safe, and reusable, which is of significant practical importance for ensuring the quality and safety of peanut oil and protecting consumer health.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of materials, and particularly relates to a material for efficiently adsorbing and removing aflatoxin B1, a preparation method and application thereof. BACKGROUND

[0002] Peanut is one of the important oil crops and export-oriented agricultural products, and the annual output has been ranked first in the world. About 52% of peanuts are used for oil pressing. Peanut is one of the crops most susceptible to infection by fungi such as Aspergillus flavus and A. parasiticus. The aflatoxins (AFs) secreted by these fungi during metabolism have a very high affinity for peanut oil. So far, more than 20 different forms of AFs have been found, among which AFB1 is the most toxic and is a class I carcinogen. Its toxicity is 10 times that of potassium cyanide, which seriously threatens the safety of peanut oil food, not only causing economic losses, but also posing a major threat to human health.

[0003] At present, the main methods for removing aflatoxin B1 in peanut oil are mechanical removal, biological removal, chemical removal (alkali method, ammonia treatment, chlorine dioxide treatment, sodium sulfite treatment, etc.) and physical removal (colorimetric selection, sunning, heating, irradiation, adsorption, etc.). The mechanical removal method usually refers to removing moldy particles by manual or mechanical methods, or removing the peanut skin with high toxin content by rolling. The existing peanut oil raw material screening and impurity removal process is mostly limited to only one screening process, which cannot effectively reduce aflatoxin B1 in peanut oil. The biological removal method mainly utilizes the antagonistic effect between organisms to inhibit the growth of toxin-producing fungi, thereby reducing the contamination of mycotoxins to food, or utilizing the adsorption of microorganisms and the degradation of mycotoxins by microbial metabolites. The biological removal method has relatively mild treatment conditions, but it is found that only a few types of microorganisms can degrade toxins, and the degradation capacity is not the same, and it cannot guarantee whether the quality of the food treated by biological detoxification is reduced or even whether new toxins are produced. Chemical removal of mycotoxins refers to the conversion of mycotoxins into non-toxic substances under the action of strong acid, strong base or oxidizing agent. The chemical method has good detoxification effect, but has strong corrosion, the toxicity of intermediate products is uncertain, and the sensory quality and nutritional value of food are greatly damaged. The physical removal method includes water washing, sunning, ultraviolet irradiation and adsorption. Ultraviolet irradiation can effectively remove aflatoxin B1 in peanut oil and can be used for producing strong-flavored peanut oil without producing wastewater, but the technical requirements are high and cannot be popularized due to patent restrictions. The adsorption method utilizes the unique adsorption capacity and special molecular space structure of the adsorbent to adsorb aflatoxin B1 in peanut oil, and the operation is simple, which is also a common removal method at present. At present, commonly used adsorbents include activated carbon, diatomite, white clay, attapulgite, montmorillonite, etc., but the low adsorption capacity of the material, poor separation effect and low reusability are still the bottlenecks of the practical application of the adsorbent.

[0004] Magnetic materials have special magnetic response properties. When an external magnetic field is applied, the magnetic adsorbent can quickly gather and settle and separate from the reaction solution, which can greatly save time, effectively reduce the loss of adsorbent and avoid the loss of active components. Graphitic carbon nitride (g-C3N4) rich in polyamino has special chemical and thermal stability, including ultrahigh hardness, low density, good biocompatibility, surface modification and strong adsorption affinity. Therefore, it is necessary to develop a magnetic functional nanomaterial with good biocompatibility, strong adsorption capacity and reusability for removing aflatoxin B1 in peanut oil according to the hydrophobic properties of peanut oil and the structural characteristics of aflatoxin B1. SUMMARY

[0005] In order to solve the above technical problems, the application provides a material for efficiently adsorbing and removing aflatoxin B1 and a preparation method and application thereof.

[0006] To achieve the above object, the application adopts the following technical solutions:

[0007] The application provides a material for efficiently adsorbing and removing aflatoxin B1, which is tannic acid magnetic graphite phase carbon nitride material.

[0008] The application provides a preparation method of the material for efficiently adsorbing and removing aflatoxin B1.

[0009] S1, graphite phase carbon nitride is ultrasonically dispersed in a solvent, FeCl3·6H2O and FeCl2·4H2O are dissolved in water and added to the carbon nitride dispersion liquid, heating and stirring reaction is carried out, ammonia water is added to the reaction system and continues to be stirred, after the solution is cooled, water and anhydrous ethanol are used for washing several times, and magnetic graphite phase carbon nitride is obtained by drying and grinding.

[0010] S2, the magnetic graphite phase carbon nitride and tannic acid obtained above are mixed and dissolved in ultrapure water to carry out ultrasonic fusion reaction, after the reaction is completed, the ultrapure water is used for washing, and tannic acid magnetic graphite phase carbon nitride (TA-g-C3N4 / Fe3O4) is obtained after drying.

[0011] As described above, in step S1, the graphite phase carbon nitride is prepared by calcining urea at a high temperature of 500-600 ℃ under air flow for 1-3 h.

[0012] As described above, in step S1, the graphite phase carbon nitride is mixed with the solvent at a mass-volume ratio of 1:3-5, the solvent is an ethanol aqueous solution with a volume ratio of 25-50%, and the ultrasonic time is 3-5 h.

[0013] As described above, in step S1, the molar ratio of FeCl3·6H2O and FeCl2·4H2O is 1-4:1, the mass concentration of FeCl3·6H2O and FeCl2·4H2O in water is 0.10-10 g / mL, the FeCl3 and FeCl2 solution is mixed with the graphite phase carbon nitride dispersion liquid at a volume ratio of 1:20-30, the concentration of ammonia water is 5-15 mol / L, the volume of ammonia water added is 1 / 2-1 times of water, the heating and stirring reaction condition is stirring at 70-90 ℃ for 15-60 min, and the drying condition is vacuum drying at 50-70 ℃ for 8-10 h.

[0014] Further preferably, the volume ratio of the solvent, water and ammonia water is 50:2:1-2.

[0015] The preparation method as described above, in step S2, the mass ratio of the magnetic graphite phase carbon nitride and tannic acid is 1:3-5; the power of the ultrasonic is 40-53 kHz, the time of the ultrasonic reaction is 6-8 h, the reaction temperature is 25-60 DEG C, and the drying condition is 50-70 DEG C vacuum drying for 8-10 h.

[0016] The third aspect of the present application provides the application of the material obtained by the preparation method as described above in adsorbing aflatoxin B1 in vegetable oil.

[0017] Preferably, the tannic acid magnetic graphite phase carbon nitride material is added into the vegetable oil at 0.05-5 mg / mL, and after oscillation adsorption for 60-300 min, magnetic separation is carried out, so that the aflatoxin B1 in the vegetable oil can be adsorbed and removed.

[0018] The tannic acid magnetic graphite phase carbon nitride material obtained by magnetic separation is mixed with acetone for 30 s-2 min, and then eluted by magnetic separation for 2-3 times, and then the eluted tannic acid magnetic graphite phase carbon nitride material is used again for adsorption and removal of aflatoxin in vegetable oil.

[0019] The fourth aspect of the present application provides a method for efficiently adsorbing and removing aflatoxin B1 in vegetable oil, wherein the tannic acid magnetic graphite phase carbon nitride material obtained by the preparation method as described above is added into vegetable oil containing aflatoxin, and after oscillation adsorption for 60-300 min, magnetic separation is carried out.

[0020] Further, preferably, the vegetable oil is preferably peanut oil.

[0021] The method as described above, preferably, the concentration of the tannic acid magnetic graphite phase carbon nitride material in the vegetable oil is ≤5 mg / mL, and preferably 0.5 mg / mL.

[0022] The method as described above, preferably, the oscillation adsorption condition is room temperature, preferably 25 DEG C, the rotation speed is 200 r / min, and the time is preferably 60 min.

[0023] The reuse method of the tannic acid magnetic graphite phase carbon nitride material as described above, wherein the tannic acid magnetic graphite phase carbon nitride material adsorbed with aflatoxin B1 is cleaned with acetone first, and then washed with acetonitrile, and after drying, it can be reused for adsorption of aflatoxin B1.

[0024] The present application has the following beneficial effects:

[0025] The application provides a material for efficiently adsorbing and removing aflatoxin B1, which is a tannic acid magnetic graphite phase carbon nitride material, the tannic acid magnetic graphite phase carbon nitride contains polyhydroxy and polyamino groups, has excellent adsorption and removal effect on aflatoxin B1, has large material adsorption capacity and is safe and non-toxic, the adsorption step is simple to operate, and the material can be produced and used on a large scale.

[0026] The application also provides a preparation method of the tannic acid magnetic graphite phase carbon nitride material for efficiently adsorbing and removing aflatoxin B1 in peanut oil, the preparation process is simple, raw materials are easy to obtain, and the material is safe and low in preparation cost.

[0027] The tannic acid magnetic graphite phase carbon nitride prepared by the application has magnetism, is convenient for magnetic separation from vegetable oil, can be repeatedly used after elution, and has a removal rate of more than 85% on aflatoxin B1 after 6 times of repetition. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 It is a scanning electron microscope image of the tannic acid magnetic graphite phase carbon nitride.

[0029] Figure 2 It is a scanning electron microscope maping image of the tannic acid magnetic graphite phase carbon nitride.

[0030] Figure 3 It is an EDS energy spectrum image of the tannic acid magnetic graphite phase carbon nitride.

[0031] Figure 4 It is an XRD spectrum image of the tannic acid magnetic graphite phase carbon nitride.

[0032] Figure 5 It is an FTIR characterization image of the tannic acid magnetic graphite phase carbon nitride.

[0033] Figure 6 It is an optimization of material proportion of the tannic acid magnetic graphite phase carbon nitride preparation condition.

[0034] Figure 7 It is an optimization of temperature of the tannic acid magnetic graphite phase carbon nitride preparation condition.

[0035] Figure 8 It is an optimization of time of the tannic acid magnetic graphite phase carbon nitride preparation condition.

[0036] Figure 9 It is an optimization of AFB1 adsorption temperature of the tannic acid magnetic graphite phase carbon nitride.

[0037] Figure 10 It is an optimization of AFB1 adsorption time of the tannic acid magnetic graphite phase carbon nitride.

[0038] Figure 11The removal rate of aflatoxin B1 by tannic acid magnetic graphite phase carbon nitride is repeated 6 times. DETAILED DESCRIPTION

[0039] The application provides tannic acid magnetic graphite phase carbon nitride for efficiently adsorbing and removing aflatoxin B1 in peanut oil and a material preparation method and application thereof. The application principle of the application is that tannic acid rich in polyhydroxy is modified on carbon nitride with built-in N functional groups, and the tannic acid modified magnetic graphite phase carbon nitride nanocomposite material can be prepared, the problem of low AFB1 adsorption capacity is solved by using the hydroxyl group on the surface of tannic acid and the amino group on the surface of graphite phase carbon nitride, and the problems of poor separation effect of the adsorption material and reuse are solved by using magnetism.

[0040] The application provides a preparation method of tannic acid magnetic graphite phase carbon nitride for efficiently adsorbing and removing aflatoxin B1 in peanut oil.

[0041] (1) Preparation of graphite phase carbon nitride

[0042] The graphite phase carbon nitride is prepared by using a thermal polymerization method, urea is wrapped with aluminum foil, placed in an alumina crucible, then placed in a muffle furnace and heated to 500-600 ℃, calcined for 1-3 h under air flow, and graphite phase carbon nitride (g-C3N4) is obtained.

[0043] (2) Preparation of magnetic graphite phase carbon nitride

[0044] The magnetic graphite phase carbon nitride is prepared by using an in-situ precipitation method, graphite phase carbon nitride is ultrasonically dispersed in a solvent, FeCl3·6H2O and FeCl2·4H2O are dissolved in ultrapure water and added to the carbon nitride dispersion liquid, heated and stirred to react, ammonia water is added to the reaction system and continues to be stirred, after the solution is cooled, it is washed with ultrapure water and anhydrous ethanol for several times, and dried and ground for use.

[0045] (3) Preparation of tannic acid magnetic graphite phase carbon nitride

[0046] The tannic acid magnetic graphite phase carbon nitride is prepared by using an ultrasonic fusion method, tannic acid and magnetic graphite phase carbon nitride are mixed and dissolved in ultrapure water for ultrasonic fusion reaction, after the reaction is completed, the tannic acid magnetic graphite phase carbon nitride is obtained by washing with ultrapure water and drying and grinding.

[0047] The preparation method described above is preferably, in step (1), the heating rate is 5-10 ℃ / min, the calcination temperature is 500-600 ℃, and the calcination time is 1-3 h.

[0048] The preparation method described above, preferably, in step (2), the ultrasonic dispersion solvent is an ethanol aqueous solution with a volume ratio of 25-50%, the volume-mass ratio of the ethanol aqueous solution to the graphite phase carbon nitride is 3-5:1 mL / mg, the ultrasonic time is 5 h; the amount ratio of FeCl3·6H2O to FeCl2·4H2O is 1-4:1 in molar ratio, and the mass concentration of FeCl3·6H2O and FeCl2·4H2O in water is 0.10-10 g / mL ultrapure water.

[0049] The preparation method described above, preferably, in step (2), the reaction temperature of the graphite phase carbon nitride and FeCl3· 6H2O and FeCl2·4H2O is 80-100 DEG C, the reaction time is 30-60 min, the concentration of the added ammonia water is 5-15 mol / L, the volume of the added ammonia water is 1 / 2-1 times of the ultrapure water, the continuous stirring reaction time is 30-60 min, and the drying condition is 60 DEG C vacuum drying for 10 h.

[0050] The preparation method described above, preferably, in step (3), the mass ratio of the tannic acid to the magnetic graphite phase carbon nitride is 3-5:1, the ultrasonic power is 50 kHz, the ultrasonic reaction time is 6-8 h, the reaction temperature is 25-60 DEG C, and the drying condition is 60 DEG C vacuum drying for 10 h.

[0051] The embodiment of the present application also provides a method for removing aflatoxin B1 in peanut oil by using the tannic acid magnetic graphite phase carbon nitride obtained by the preparation method described above, specifically, the tannic acid magnetic graphite phase carbon nitride material obtained by the preparation method described above is added into plant oil containing aflatoxin, and then magnetic separation is performed after oscillation adsorption for 60-300 min.

[0052] Preferably, the adsorption temperature is room temperature, preferably 25 DEG C, and the rotation speed is 200 r / min.

[0053] The following examples are used to further illustrate the present application, but should not be construed as limiting the present application. Modifications or replacements made to the present application without departing from the spirit and essence of the present application shall all fall within the scope of the present application.

[0054] Unless otherwise specified, the technical means used in the examples is a routine means familiar to those skilled in the art, and the reagents used in the examples are all analytical pure or above specifications.

[0055] Example 1: Preparation of tannic acid magnetic graphite phase carbon nitride

[0056] (1) The carbon nitride was prepared by a thermal polymerization method. 10 g of urea was wrapped with aluminum foil and placed in an aluminum crucible, which was sintered and heated at 550 °C for 3 h in a muffle furnace with a heating rate of 5 °C / min. Yellow carbon nitride was collected. The magnetic graphite phase carbon nitride was prepared by an in-situ precipitation method.

[0057] (2) First, 125 mg of carbon nitride was dispersed in 500 mL of 50% ethanol aqueous solution by volume and ultrasonically treated at room temperature for 5 h to obtain a carbon nitride suspension. Second, FeCl3·6H2O (1.838 g) and FeCl2·H2O (0.703 g) were separately dissolved in 20 mL of double-ultra-pure water and added to the dispersed carbon nitride suspension. Third, the mixture was stirred at 80 °C for 30 min, and then 10 mL of ammonia solution (NH4OH) with a concentration of 14.84 mol / L was quickly injected into the reaction mixture. The resulting mixture was stirred for another 30 min, and then the reaction mixture was cooled and washed several times with double-ultra-pure water and anhydrous ethanol. Finally, the obtained precipitate was dried at 60 °C under vacuum for 10 h and ground for use.

[0058] (3) The tannic acid magnetic graphite phase carbon nitride was prepared by an ultrasonic fusion method. 50 g of tannic acid and 10 g of magnetic graphite phase carbon nitride obtained in the above step were added to 100 mL of deionized water, and ultrasonically reacted at 60 °C for 6 h. The product was washed several times with deionized water and dried in an oven at 60 °C for 10 h to obtain the tannic acid magnetic graphite phase carbon nitride.

[0059] The tannic acid magnetic graphite phase carbon nitride was ultrasonically dispersed in an ethanol solution, which was then dropped on a copper mesh support film. After the ethanol was completely volatilized, scanning electron microscopy (JSM-IT300) was used for characterization testing. As shown in FIG. 6, the results show that the tannic acid is attached to the surface of the magnetic graphene carbon nitride, Figure 1 Figure 2 which is a scanning electron microscope map, indicating that the composite material contains C, N, O, Cl and Fe elements, Figure 3 which is an EDS energy spectrum, further analyzing the content of elements in the composite material, the content of C, N, O, Cl and Fe elements is 11.88%, 3.35%, 46.22%, 0.3% and 38.25% respectively, which verifies the successful preparation of the material from different angles.

[0060] X-ray diffractometer (D8 Advance) was used to characterize and test the prepared tannic acid magnetic graphite phase carbon nitride material (TA-g-C3N4 / Fe3O4), tannic acid (Tanin), ferric oxide (Fe3O4) and carbon nitride (g-C3N4). As shown in FIG. 7, Figure 4 ​As shown, the results show that the tannic acid magnetic graphitic phase carbon nitride material contains characteristic peaks of tannic acid, ferroferric oxide and carbon nitride, indicating that the composite material is successfully prepared. Fourier transform infrared spectrometer (Nicolet 6700) was used for FTIR characterization test. As shown in Figure 5 As shown, the FTIR absorption peaks of tannic acid magnetic graphitic phase carbon nitride contain absorption peaks of tannic acid and magnetic graphitic phase carbon nitride, indicating that the material is successfully prepared. Example 2

[0061] In order to obtain the tannic acid magnetic graphitic phase carbon nitride with the best adsorption performance for aflatoxin B1, the preparation conditions of the material were optimized, including the composite ratio of tannic acid and magnetic graphitic phase carbon nitride, ultrasonic composite temperature and ultrasonic composite time. 30 mg, 60 mg, 150 mg and 300 mg of tannic acid were mixed with 30 mg of magnetic graphitic phase carbon nitride and dissolved in 20 mL of ultrapure water, and the preparation ratio was optimized in the range of 1:1 to 10:1. After ultrasonic reaction at a power of 53 kHz for 6 h, tannic acid magnetic graphitic phase carbon nitride with different ratios was obtained. 5 mg of tannic acid magnetic graphitic phase carbon nitride adsorbent was accurately weighed and added to 10 g of peanut oil containing 20 µg / g of aflatoxin B1, and oscillation adsorption was carried out in a controllable temperature oscillator for 1 h. The supernatant was taken by magnetic separation, and then the concentration of aflatoxin B1 was detected and the removal rate was calculated. As shown in Figure 6 As shown, the adsorption performance of the composite material prepared by optimizing the mass ratio of tannic acid and magnetic graphitic phase carbon nitride to 5:1 is the best. Then, 150 mg of tannic acid was mixed with 30 mg of magnetic graphitic phase carbon nitride and dissolved in 20 mL of ultrapure water, and the ultrasonic composite temperature was optimized at 25 ℃, 35 ℃, 45 ℃ and 60 ℃. Ultrasonic was carried out for 6 h, and 5 mg of tannic acid magnetic graphitic phase carbon nitride adsorbent was accurately weighed and added to 10 g of peanut oil containing 20 µg / g of aflatoxin B1. Oscillation adsorption was carried out in a controllable temperature oscillator for 1 h. The supernatant was taken by magnetic separation, and then the concentration of aflatoxin B1 was detected and the removal rate was calculated. Through optimization, it was determined that 60 ℃ was the best synthesis temperature Figure 7 ). Then, 150 mg of tannic acid was mixed with 30 mg of magnetic graphitic phase carbon nitride and dissolved in 20 mL of ultrapure water, and ultrasonic composite was carried out at 60 ℃. The composite time was optimized for 1 h, 2 h, 4 h and 6 h. 5 mg of tannic acid magnetic graphitic phase carbon nitride adsorbent was accurately weighed and added to 10 g of peanut oil containing 20 µg / g of aflatoxin B1. Oscillation adsorption was carried out in a controllable temperature oscillator for 1 h. The supernatant was taken by magnetic separation, and then the concentration of aflatoxin B1 was detected and the removal rate was calculated. As shown in Figure 8The results show that the synthesis reaction time is determined to be 6 h. Therefore, the preparation conditions of tannin acid magnetic graphite phase carbon nitride with the best adsorption performance for aflatoxin B1 are determined to be 5:1 of tannin acid and magnetic graphite phase carbon nitride at 60 ℃ for 6 h of ultrasonic compounding.

[0062] Example 3 Adsorption removal method of aflatoxin B1 in peanut oil

[0063] Accurately weigh 5 mg of the tannin acid magnetic graphite phase carbon nitride adsorbent prepared according to Example 1, and add it to 10 g of peanut oil containing 20 µg / g of aflatoxin B1, and perform oscillation adsorption in a controllable temperature oscillator. Sampling is performed after adsorption at a set temperature of 25 ℃, 37.5 ℃, 50 ℃ and a time of 5, 10, 20, 30, 40, 60, 90, 120 min, respectively. The supernatant is obtained by magnetic separation, and then the concentration of aflatoxin B1 is detected. Specifically, to obtain the best effect, the adsorption conditions are optimized, and the adsorption oscillation is performed at 25 ℃, 37.5 ℃ and 50 ℃ for 60 min, respectively, and the removal rate of aflatoxin B1 is determined. The results are shown in Figure 9 The results show that the adsorption effect at 25 ℃ is the best after optimization. The adsorption time is optimized for 5 min, 10 min, 20 min, 30 min, 40 min, 60 min, 90 min and 120 min, and the results are shown in Figure 10 The results show that the adsorption equilibrium is reached at 60 min. After adsorption equilibrium, the adsorbent is separated from the oil by magnetic separation, and the content of aflatoxin B1 in the supernatant is determined by mass spectrometry analysis method, and the adsorption effect of tannin acid magnetic graphite phase carbon nitride material on aflatoxin B1 in peanut oil is calculated. The mass spectrometry analysis for aflatoxin B1 detection uses Waters XEVO TQ-S mass spectrometer, adopts electrospray ionization source (ESI), and detects in multiple reaction monitoring (MRM) mode. The optimized parameters are as follows: ion source temperature 150 ºC, desolvation gas temperature 500 ºC, capillary voltage 2.5 kV / -0.8 kV, cone gas flow rate 150 L / h, and desolvation gas flow rate 1000 L / h (see Table 1 for details). The mobile phase is 1 mM NH4AC (A) and MeOH (B), and the time is 6 min (see Table 2 for details).

[0064] Table 1 Mass spectrometry analysis parameters of target compounds

[0065] mycotoxin ion mode retention time / min parent ion ( / ) daughter ion ( / ) cone voltage / V collision energy / eV AFB1 ESI+ 5.08 313.2 214.1*,285.1 35 25,25

[0066] * Quantitative ion

[0067] Table 2 Mobile phase gradient conditions

[0068] time / min flow rate / (mL / min) A (1 mM NH4AC) B% (MeOH) Curve 0.00 0.3 95 5 0 0.50 0.3 95 5 6 5 0.3 10 90 6 5.1 0.3 10 90 6 6.0 0.3 95 5 6

[0069] The tannin acid magnetic graphite phase carbon nitride material after the above adsorption of aflatoxin B1 was first added with 5 mL of acetone and stirred for 30 s, then magnetically separated, 5 mL of acetonitrile was added after the supernatant was removed, and then magnetically separated after oscillation for 30 min, the above steps were repeated twice, the two supernatants were mixed, and then membrane filtration was performed, and then machine detection was performed. The elution amount. The tannin acid magnetic graphite phase carbon nitride after elution was dried in a 60°C oven for 10 h, and was reused for the adsorption and removal of aflatoxin B1 in peanut oil, and the adsorption-elution was repeated for 6 times, the adsorption removal rate of aflatoxin B1 was calculated according to the following formula, and the results are shown in Table 3, and a column chart is shown in Figure 11 .

[0070] Adsorption amount of TA-g-C3N4 / Fe3O4 to AFB1 Q e The calculation formula is as follows:

[0071]

[0072]

[0073] Q e Saturation adsorption amount, μg / mg; C0 and C e Initial and equilibrium concentrations of AFB1 (μg / L), V is the solution volume (mL), and W is the adsorbent weight (mg).

[0074] Table 3 Gradient conditions of mobile phase TA-g-C3N4 / Fe3O4 adsorption to AFB1

[0075] number of repetitions removal rate (%) RSD 1 94.22 6.8 2 92.15 7.2 3 90.36 5.2 4 89.28 4.9 5 87.49 7.1 6 85.82 3.4 g-C3N4 / Fe3O4 45.28 4.5

[0076] The results show that after 6 times of adsorption and desorption, the adsorption removal rate of aflatoxin B1 by the tannin acid magnetic graphite phase carbon nitride is still greater than 85%. The adsorption effect is significantly higher than that of g-C3N4 / Fe3O4 without tannin acid modification, which shows that the tannin acid magnetic graphite phase carbon nitride prepared by the application has good adsorption performance to aflatoxin B1, and has strong binding capacity to aflatoxin B1. It can be reused after elution, and has good economic utilization value.

Claims

1. A method for preparing a material for efficient adsorptive removal of aflatoxin B1, characterized in that, It comprises the following steps: S1, dispersing graphite phase carbon nitride in a solvent by ultrasonic, dissolving FeCl3·6H2O and FeCl2·4H2O in water, then adding them into the carbon nitride dispersion and heating and stirring to react, adding ammonia water into the reaction system and continuing to stir, washing the solution with water and anhydrous ethanol several times after cooling, and drying to obtain magnetic graphite phase carbon nitride; S2, mixing the magnetic graphite phase carbon nitride obtained above and tannic acid in ultrapure water and performing ultrasonic fusion reaction, wherein the mass ratio of the magnetic graphite phase carbon nitride and tannic acid is 1:3-5; after the reaction, washing with ultrapure water, drying to obtain tannic acid magnetic graphite phase carbon nitride; In step S1, the mass-volume ratio of the graphite phase carbon nitride to the solvent is 1:3-5 mL / mg, and the solvent is an ethanol aqueous solution with a volume ratio of 25-50%; the ultrasonic time is 3-5 h; In step S1, the molar ratio of FeCl3·6H2O and FeCl2·4H2O is 1-4:1, wherein the mass concentration of FeCl3·6H2O and FeCl2·4H2O in water is 0.10-10 g / mL, the FeCl3 and FeCl2 solution is mixed with the graphite phase carbon nitride dispersion at a volume ratio of 1:20-30, the concentration of ammonia water is 5-15 mol / L, the volume of ammonia water added is 1 / 2-1 times of water, the heating and stirring reaction conditions are stirring at 70-90℃ for 15-60 min, and the drying conditions are vacuum drying at 50-70℃ for 8-10 h; The volume ratio of the solvent to water and ammonia water is 50:2:1-2.

2. The production method according to claim 1, characterized by, In step S1, the graphite phase carbon nitride is prepared by calcining urea at a high temperature of 500-600℃ in an air flow for 1-3 h.

3. The production method according to claim 1, characterized by, In step S2, the ultrasonic power is 40-53 kHz, the ultrasonic reaction time is 6-8 h, the reaction temperature is 25-60℃, and the drying conditions are vacuum drying at 50-70℃ for 8-10 h.

4. The use of the material obtained by the preparation method of any one of claims 1-3 in adsorbing aflatoxin B1 in vegetable oil.

5. Use according to claim 4, characterized in that, The tannic acid magnetic graphite phase carbon nitride material is added to the vegetable oil at 0.05-5 mg / mL, and after oscillation adsorption for 60-300 min, magnetic separation is performed to remove aflatoxin B1 in the vegetable oil.

6. Use according to claim 5, characterized in that, The multi-tannic acid magnetic graphite phase carbon nitride material obtained by magnetic separation is mixed with acetone for 30 s-2 min, then magnetic separation is performed, elution is performed 2-3 times, and then the eluted tannic acid magnetic graphite phase carbon nitride material is used again for adsorption and removal of aflatoxin in vegetable oil.

7. A method for efficiently adsorbing and removing aflatoxin B1 in vegetable oil, wherein the tannic acid magnetic graphite phase carbon nitride material obtained by the preparation method of any one of claims 1-3 is added to vegetable oil containing aflatoxin, and after oscillation adsorption for 60-300 min, magnetic separation is performed.

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