A composite material for reducing 3-chloropropanol esters and glycidyl esters in diglyceride edible oils, its preparation method and application.

Abstract

The application provides a composite material for reducing 3-chloropropanol ester and glycidyl ester in glyceride edible oil, a preparation method and application, and belongs to the technical field of edible oil processing. The preparation method of the composite material comprises the following steps: S1, mixing graphene oxide, sodium dodecyl sulfate, sec-butylamine and an alkaline aqueous solution to obtain a precursor solution; S2, adjusting the temperature of the precursor solution obtained in step S1 to 60-80 DEG C, adding a silicon source and a metal salt solution dropwise, maintaining the reaction at 60-80 DEG C, and post-treating to obtain the composite material. The composite material can effectively reduce the content of 3-chloropropanol ester and glycidyl ester in glyceride edible oil when the glyceride oil is treated, and has good recyclability.

Description

Technical Field

[0001] This invention belongs to the field of edible oil processing technology, and relates to a composite material, preparation method and application of reducing 3-chloropropanol ester and glycidyl ester in diglyceride edible oil. Background Technology

[0002] Chloropropanol esters are foodborne contaminants formed by the esterification of chloropropanol and fatty acids under high-temperature conditions. Chloropropanol esters include esters formed from fatty acids and alcohols such as 3-chloro-1,2-propanediol, 2-chloro-1,3-propanediol, 1,3-dichloro-2-propanol, and 2,3-dichloro-1-propanol. Among these, 3-chloropropanol esters have the highest contamination levels. Studies have shown that 3-chloropropanol esters can damage the kidneys, liver, and reproductive system; therefore, the content of 3-chloropropanol esters in food should be controlled, especially in edible oil products.

[0003] Glycidyl esters of fatty acids, also known as fatty acid-2,3-epoxypropyl esters, are impurities formed by the dehydration and cyclization of the 2,3-hydroxyl groups of 1-glycerol fatty acid esters (1-monoglyceride) at high temperatures. Common glycidyl esters of fatty acids include glycidyl oleate and glycidyl palmitate, which are commonly produced during the refining process of vegetable oils. The molecular structure of glycidyl ester compounds contains an epoxy ethyl group, which may react with amino groups in proteins / nucleic acids after ingestion, resulting in toxicity. In the production of edible oils, especially diglyceride edible oils, due to the potential involvement of 1-monoglyceride intermediates in the production process, greater attention should be paid to controlling the content of glycidyl esters in the product.

[0004] Currently, there are two main methods for controlling the content of 3-chloropropanol esters and glycidyl esters in edible oils. One method is to reduce the 3-chloropropanol ester content by controlling the amount of chlorine-containing substances used in the edible oil production process. For example, Chinese invention patent CN118978952A controls the 3-chloropropanol ester content in oil products by controlling the chloride ion content of the water used in the production process. This method can control the content of 3-chloropropanol esters and glycidyl esters at the source, but it involves improvements to the entire process and has low compatibility with different synthesis processes. The second method is to use adsorption materials to adsorb the glycidyl ester content in edible oils to reduce the content of 3-chloropropanol esters and glycidyl esters in the product. For example, Wang Geping et al. pointed out in the article "Reduction of Glycidyl Ester Content in Edible Oils by Adsorption Method and Its Kinetic Study" (Modern Food Science and Technology, 2019, 35(2), 171-178) that specific activated carbon materials can effectively adsorb glycidyl esters in edible oils, with a removal rate of up to 95.92%. The method of using adsorbent materials to reduce 3-chloropropanol esters and glycidyl esters in edible oils is highly adaptable and can be applied to all stages of edible oil production.

[0005] However, the adsorption method for removing 3-chloropropanol esters and glycidyl esters from diglyceride edible oils still faces the following bottleneck problems: (1) The high content of diglycerides in diglyceride edible oils may compete with the adsorption of 3-chloropropanol esters and glycidyl esters, leading to a decrease in the adsorption rate of impurities; (2) The low recycling rate of adsorption materials increases the overall production cost. Summary of the Invention

[0006] In view of the above-mentioned technical problems, the purpose of this invention is to provide a composite material, its preparation method, and its application for reducing the content of 3-chloropropanol esters and glycidyl esters in diglyceride edible oils. A method for preparing a composite material suitable for reducing the content of 3-chloropropanol esters and glycidyl esters in diglyceride edible oils is provided. This composite material uses silica as a base material and incorporates a specific ratio of doped graphene oxide and Mg... 2+ Al 3+ A composite material was formed that selectively adsorbs chlorine-containing 3-chloropropanol esters and glycidyl esters containing glycidyl oxide. The inventors unexpectedly discovered that, compared to common structure modifiers such as triethanolamine, using sec-butylamine to adjust the overall structure of the material further improved the composite material's effect on reducing the content of 3-chloropropanol esters and glycidyl esters in diglyceride oils. Applying this composite material to the production process of diglyceride edible oils effectively reduced the content of 3-chloropropanol esters and glycidyl esters.

[0007] To achieve the above-mentioned objectives, in one aspect, the present invention provides a method for preparing a composite material that reduces 3-chloropropanol esters and glycidyl esters in diglyceride edible oils, comprising the following steps:

[0008] S1. Mix graphene oxide, sodium dodecyl sulfate, sec-butylamine and an alkaline aqueous solution to obtain a precursor solution;

[0009] S2. Adjust the temperature of the precursor solution obtained in step S1 to 60-80℃, add silicon source and metal salt solution dropwise, maintain the reaction at 60-80℃, and then perform post-treatment to obtain the composite material.

[0010] In step S2, the metal salt solution is an aqueous solution of magnesium salt and aluminum salt. The magnesium salt is selected from one or two of magnesium nitrate and magnesium sulfate, and the aluminum salt is selected from one or two of aluminum nitrate and aluminum sulfate. The molar ratio of magnesium to aluminum in the aqueous solution of magnesium salt and aluminum salt is 3-5:1.

[0011] Further, the molar ratio of magnesium to aluminum in the magnesium salt and aluminum salt aqueous solution can be 3:1, 3.1:1, 3.2:1, 3.3:1, 3.4:1, 3.5:1, 3.6:1, 3.7:1, 3.8:1, 3.9:1, 4:1, 4.1:1, 4.2:1, 4.3:1, 4.4:1, 4.5:1, 4.6:1, 4.7:1, 4.8:1, 4.9:1, or 5:1.

[0012] As an embodiment of the present invention, the molar ratio of magnesium to aluminum is 3:1, 4:1 or 5:1, preferably 4:1.

[0013] Preferably, in step S1, the alkaline aqueous solution is an aqueous solution of at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate.

[0014] As an embodiment of the present invention, the alkaline aqueous solution is an alkaline aqueous solution of sodium hydroxide.

[0015] Preferably, in step S1, the pH of the alkaline aqueous solution is 12-13.

[0016] As an embodiment of the present invention, the pH of the alkaline aqueous solution is 12.5.

[0017] Preferably, in step S2, the silicon source is selected from one or both of tetraethyl silicate and tetramethyl silicate. As an embodiment of the present invention, the silicon source is tetraethyl silicate (also known as tetraethoxysilane, TEOS).

[0018] Preferably, the ratio of the amount of graphene oxide, sodium dodecyl sulfate, sec-butylamine, alkaline aqueous solution and silicon source in step S1 to that in step S2 is 0.3-0.5:0.4-0.6:0.05-0.15:100:1-2, in g:g:g:mL:mL.

[0019] As an embodiment of the present invention, the ratio of the amount of graphene oxide, sodium dodecyl sulfate, sec-butylamine, alkaline aqueous solution and silicon source in step S1 to that in step S2 is 0.3:0.6:0.05:100:2, in g:g:g:mL:mL.

[0020] As an embodiment of the present invention, the ratio of the amount of graphene oxide, sodium dodecyl sulfate, sec-butylamine, alkaline aqueous solution and silicon source in step S1 to that in step S2 is 0.5:0.4:0.15:100:1, in g:g:g:mL:mL.

[0021] In a preferred embodiment of the present invention, the ratio of the amount of graphene oxide, sodium dodecyl sulfate, sec-butylamine, alkaline aqueous solution in step S1 to the amount of silicon source in step S2 is 0.4:0.5:0.1:100:1.5, in g:g:g:mL:mL.

[0022] Preferably, in step S2, the silicon source is selected from one or two of tetraethyl silicate and tetramethyl silicate, and the addition of silicon source and metal salt solution specifically involves adding silicon source and metal salt solution dropwise to the precursor solution while stirring.

[0023] Preferably, in step S2, the concentration of aluminum ions in the metal salt solution is 83-125 mmol / L, more preferably 100 mmol / L.

[0024] Preferably, in step S2, the volume ratio of the silicon source to the metal salt solution is 1-2:0.2, more preferably 1.5:0.2.

[0025] Preferably, in step S2, the dropping rates of the silicon source and the metal salt solution are: 0.05-0.2 mL / min for the silicon source and 0.05-0.2 mL / min for the metal salt solution.

[0026] More preferably, in step S2, the dropping rates of the silicon source and the metal salt solution are: 0.1 mL / min for the silicon source and 0.1 mL / min for the metal salt solution.

[0027] Preferably, in step S2, the reaction time is 2-4 hours.

[0028] Preferably, in step S2, the post-processing includes the following steps:

[0029] Centrifuge to collect the precipitate, wash it 1-3 times with cyclohexane, 1-3 times with ethanol, and 1-3 times with water, and then dry it.

[0030] On the other hand, the present invention provides a composite material obtained by the above-described preparation method.

[0031] In another aspect, the present invention provides the application of the above-mentioned composite material in eliminating 3-chloropropanol esters and glycidyl esters in diglyceride edible oils.

[0032] Preferably, the application includes the following steps:

[0033] The crude edible oil containing diglycerides and the composite material are added to a fluidized bed for adsorption and separation to obtain the treated edible oil containing diglycerides.

[0034] More preferably, the volume ratio of the crude edible oil to the weight of the composite material is 1:0.1-10, in L:g;

[0035] The adsorption temperature is 60-70℃, the adsorption fluidization rate is 0.2-1m / s, and the adsorption time is 20-40min.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] (1) This invention provides a novel composite material suitable for reducing 3-chloropropanol esters and glycidyl esters in diglyceride edible oils. It employs a co-doping method with graphene oxide, magnesium ions, and chloride ions to effectively improve the adsorption performance for chlorine-containing 3-chloropropanol esters and epoxy-ethyl-containing glycidyl esters. Simultaneously, the inventors unexpectedly discovered that using sec-butylamine as a structure modifier achieves better adsorption effects than conventional structure modifiers such as triethanolamine.

[0038] (2) The composite material provided by the present invention has good recyclability. Within 5 cycles, the removal rate of 3-chloropropanol ester and glycidyl ester in crude edible oil of diglycerides decreases less, which is conducive to the recycling of adsorbent material.

[0039] (3) Applying the novel composite material of the present invention to the processing of crude edible oil of diglycerides effectively reduces the content of 3-chloropropanol ester and glycidyl ester in crude edible oil of diglycerides. Detailed Implementation

[0040] Terminology and Declarations of this Invention:

[0041] 1. Articles “a,” “a kind,” and “the”: These include plural objects unless otherwise explicitly specified as a single (kind) object.

[0042] 2. Numerical Range: Unless otherwise expressly stated, all ranges or ratios disclosed herein shall be construed as including any and all subranges or subratios contained herein. For example, a stated range or ratio of 1 to 30 shall be considered to be included between the minimum value of 1 and the maximum value of 30, and includes any subranges or subratios, integers, decimals, or subranges or subratios consisting of integers or decimals, including endpoints.

[0043] The following non-limiting embodiments are intended to enable those skilled in the art to gain a more comprehensive understanding of the present invention, but do not limit the invention in any way. The following description is merely an exemplary illustration of the scope of protection of the present invention, and those skilled in the art can make various changes and modifications to the present invention based on the disclosed content, which should also fall within the scope of protection of the present invention.

[0044] The present invention will be further described below by way of specific embodiments. Unless otherwise specified, all chemical reagents used in the embodiments of the present invention were obtained through conventional commercial means. Unless otherwise specified, all contents mentioned below are mass contents. Unless otherwise specified, it is understood that the process was carried out at room temperature.

[0045] The following example uses a method for preparing graphene oxide:

[0046] The reaction vessel was fixed in a temperature-controlled water bath equipped with a magnetic stirrer, and a large amount of ice was added to the water bath to create an ice-water bath environment. 50 mL of concentrated sulfuric acid was poured into the reaction vessel, and a tetrafluoroethylene-coated magnetic stirrer was added. While stirring, 4 g of graphite powder (passed through a 100-mesh sieve) was added to the reaction vessel, followed by 2 g of anhydrous sodium nitrate. The mixture was stirred at no more than 200 rpm for 10 minutes until homogeneous. 10 g of potassium permanganate solid was weighed and added to the reaction vessel in 10 portions, controlling the reaction temperature to no more than 20 minutes. After the potassium permanganate was added, the mixture was stirred for 1 hour. The water bath was heated to 30°C, the stirring speed was increased to 400 rpm, and the reaction was carried out for 40 minutes. Then, an equal volume of deionized water was slowly added to the reaction vessel, the temperature was raised to 45°C, and the reaction was carried out for 40 minutes. The temperature was then slowly raised to 60°C, and the reaction was carried out for 40 minutes. The system temperature was controlled at 50°C, and concentrated hydrogen peroxide was added dropwise until the solution turned bright yellow. Filter while hot, wash three times with 1% hydrochloric acid solution, and then wash once with deionized water. Dry in a vacuum drying oven at 40°C to obtain graphene oxide.

[0047] Example 1

[0048] A method for preparing a composite material, comprising the following steps.

[0049] S1. Mix 0.4g of graphene oxide, 0.5g of sodium dodecyl sulfate, 0.1g of sec-butylamine and 100mL of sodium hydroxide aqueous solution with pH=12.5, and stir until completely dissolved to obtain the precursor solution.

[0050] S2. Magnesium sulfate and aluminum sulfate were mixed with an appropriate amount of water to prepare a magnesium sulfate and aluminum sulfate mixed metal salt solution with a magnesium ion concentration of 0.4 mol / L and an aluminum ion concentration of 0.1 mol / L. The temperature of the precursor solution obtained in step S1 was adjusted to 70℃. Using a syringe pump, 1.5 mL of TEOS (tetraethoxysilane) and 0.2 mL of the metal salt solution prepared above were simultaneously and uniformly injected into the precursor solution. The injection rate of TEOS was 0.1 mL / min, and the injection rate of the metal salt solution was 0.1 mL / min. After the addition was completed, the reaction was maintained at 70℃ and stirred at 400 rpm for 3 h. The precipitate was collected by centrifugation (10000 rpm, 2 min), and resuspended and washed sequentially with the following solvents: cyclohexane twice, ethanol twice, and water twice. After washing, the precipitate was collected by centrifugation (10000 rpm, 2 min), dried, and the composite material was obtained.

[0051] Example 2

[0052] Compared with Example 1, the only difference is that in step S2, the magnesium ion concentration is changed to 0.375 mol / L and the aluminum ion concentration is changed to 0.125 mol / L, while the rest are the same.

[0053] Example 3

[0054] Compared with Example 1, the only difference is that in step S2, the magnesium ion concentration is changed to 0.416 mol / L and the aluminum ion concentration is changed to 0.083 mol / L, while the rest are the same.

[0055] Example 4

[0056] Compared with Example 1, the only difference is that in step S1, the amount of graphene oxide is changed to 0.3g, the amount of sodium dodecyl sulfate is changed to 0.6g, and the amount of sec-butylamine is changed to 0.05g; in step S2, the amount of TEOS is changed to 2mL. All other steps are the same.

[0057] Example 5

[0058] Compared with Example 1, the only difference is that in step S1, the amount of graphene oxide is changed to 0.5g, the amount of sodium dodecyl sulfate is changed to 0.4g, and the amount of sec-butylamine is changed to 0.15g; in step S2, the amount of TEOS is changed to 1mL. All other steps are the same.

[0059] Example 6

[0060] Compared with Example 1, the only difference is that in step S2, the temperature of the precursor solution is adjusted to 60°C, and after the addition is completed, the temperature is maintained at 60°C for the reaction. All other aspects are the same.

[0061] Example 7

[0062] Compared with Example 1, the only difference is that in step S2, the temperature of the precursor solution is adjusted to 80°C, and after the addition is completed, the temperature is maintained at 80°C for the reaction. All other aspects are the same.

[0063] Comparative Example 1

[0064] Compared with Example 1, the only difference is that in step S2, the magnesium ion concentration is changed to 0.3 mol / L and the aluminum ion concentration is changed to 0.2 mol / L, while the rest are the same.

[0065] Comparative Example 2

[0066] Compared with Example 1, the only difference is that in step S2, the magnesium ion concentration is changed to 0.45 mol / L and the aluminum ion concentration is changed to 0.05 mol / L, while the rest are the same.

[0067] Comparative Example 3

[0068] Compared with Example 1, the only difference is that in step S1, sec-butylamine is replaced with an equal weight of triethanolamine liquid; all other aspects are the same.

[0069] Comparative Example 4

[0070] Compared with Example 1, the only difference is that in step S1, sec-butylamine is replaced with an equal weight of triethylamine liquid, and sodium dodecyl sulfate is replaced with an equal weight of hexadecyltrimethylammonium bromide; all other steps are the same.

[0071] Comparative Example 5

[0072] Compared with Example 1, the only difference is that in step S1, the addition of graphene oxide is omitted, the weight of sodium dodecyl sulfate is changed to 0.9g, and in step S2, the amount of TEOS is changed to 0.5mL. All other steps are the same.

[0073] Comparative Example 6

[0074] Compared with Example 1, the only difference is that in step S2, the temperature of the precursor solution is adjusted to 90°C, and after the addition is completed, the temperature is maintained at 90°C for the reaction. All other aspects are the same.

[0075] Application Example 1

[0076] Crude edible oil containing diglyceride (3-chloropropanol ester concentration 2724 μg / kg, glycidyl ester concentration 4819 μg / kg (calculated as glycidyl ester, the same below)) processed through degumming, deacidification, deodorization, and decolorization steps, along with the composite materials provided in the examples and comparative examples, were added to a fluidized bed for adsorption at a ratio of 5 g composite material per liter of crude oil. The adsorption temperature was 65°C, the fluidization velocity was 0.5 m / s, and the adsorption time was 30 min. After adsorption, the oil phase and solid material were separated. The oil phase was filtered through a 0.2 μm filter membrane to obtain the treated diglyceride edible oil (first cycle). Samples were taken from the treated diglyceride edible oil to detect the content of 3-chloropropanol esters and glycidyl esters (detection method: according to the detection method "rapid alkaline transesterification for the determination of 3-MCPD and differential method for the determination of glycidyl esters" recorded in standard GB / T 44621-2024 "Grain and Oil Inspection GC / MS Method for the Determination of 3-Chloropropanol Fatty Acid Esters and Glycidyl Fatty Acid Esters"). The removal rates of 3-chloropropanol esters and glycidyl esters were calculated.

[0077] 3-Chloropropanol ester removal rate = Concentration of 3-chloropropanol ester in the treated diglyceride edible oil ÷ Concentration of 3-chloropropanol ester in the crude diglyceride edible oil × 100%.

[0078] Glycidyl ester removal rate = concentration of glycidyl esters (calculated as glycidyl) in the treated diglyceride edible oil ÷ concentration of glycidyl esters (calculated as glycidyl) in the crude diglyceride edible oil × 100%.

[0079] The solid material was desorbed and regenerated. First, the solid material was resuspended and washed sequentially with the following solvents: n-hexane twice, n-butanol twice, and ethanol twice. The precipitate was collected by centrifugation. The precipitate was dispersed in a methanol solution (v / v=4:1), refluxed at 70°C for 2 hours, centrifuged, washed twice with water, and dried to obtain the desorbed and regenerated composite material.

[0080] The desorbed and regenerated composite material was then treated with the same crude edible oil containing diglycerides, using the same treatment method as the first cycle. After treatment, desorption and regeneration were performed using the same method. This was repeated five times, and the removal rates of 3-chloropropanol esters and glycidyl esters were calculated after each cycle.

[0081] Effect evaluation

[0082] The removal rates of 3-chloropropanol esters in crude edible oil by the composite materials provided in each embodiment and comparative example after 5 cycles are shown in Table 1 below.

[0083] Table 1

[0084]

[0085] As shown in Table 1, the composite material provided by this invention, in the fluidized bed process for removing 3-chloropropanol esters from crude edible oil containing diglycerides, achieves the following removal rates: 90.39%-97.94% in the first cycle of each embodiment, compared to only 82.55%-88.00% in the comparative examples; 87.27%-97.18% in the second cycle of each embodiment, compared to only 79.81%-85.29% in the comparative examples; 86.65%-96.34% in the third cycle of each embodiment, compared to only 74.29%-80.84% ​​in the comparative examples; 83.77%-96.10% in the fourth cycle of each embodiment, compared to only 73.14%-79.92% in the comparative examples; and 80.51%-94.34% in the fifth cycle of each embodiment, compared to only 69.03%-75.66% in the comparative examples. It is evident that the composite materials provided in the various embodiments of the present invention not only have a better removal effect on 3-chloropropanol esters in diglyceride oil compared with the comparative examples, but are also more conducive to recycling.

[0086] The removal rates of glycidyl esters in crude edible oil by the composite materials provided in each embodiment and comparative example after 5 cycles of experiments are shown in Table 2 below.

[0087] Table 2

[0088]

[0089] As shown in Table 2, the composite material provided by this invention, in the fluidized bed process for removing glycidyl esters from crude edible oil, achieves the following results: In the first cycle of each embodiment, the removal rate reaches 90.61%-98.28%, while in the comparative examples, the removal rate is only 82.21%-88.37%; in the second cycle of each embodiment, the removal rate reaches 88.13%-96.02%, while in the comparative examples, the removal rate is only 76.55%-85.41%; in the third cycle of each embodiment, the removal rate reaches 86.05%-95.37%, while in the comparative examples, the removal rate is only 75.69%-82.39%; in the fourth cycle of each embodiment, the removal rate reaches 86.51%-95.15%, while in the comparative examples, the removal rate is only 73.22%-80.74%; and in the fifth cycle of each embodiment, the removal rate reaches 85.97%-94.88%, while in the comparative examples, the removal rate is only 70.61%-77.02%. It is evident that the composite materials provided in the various embodiments of the present invention not only have a better removal effect on glycidyl esters in diglyceride oil compared with the comparative examples, but are also more conducive to recycling.

[0090] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, and is not intended to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions made by those skilled in the art to the technical solution of the present invention do not depart from the essence and scope of the technical solution of the present invention.

Claims

1. A method for preparing a composite material that reduces 3-chloropropanol esters and glycidyl esters in diglyceride edible oils, characterized in that, Includes the following steps: S1. Mix graphene oxide, sodium dodecyl sulfate, sec-butylamine and an alkaline aqueous solution to obtain a precursor solution; S2. Adjust the temperature of the precursor solution obtained in step S1 to 60-80℃, add silicon source and metal salt solution dropwise, maintain the reaction at 60-80℃, and then perform post-treatment to obtain the composite material. In step S2, the metal salt solution is an aqueous solution of magnesium salt and aluminum salt. The magnesium salt is selected from one or two of magnesium nitrate and magnesium sulfate, and the aluminum salt is selected from one or two of aluminum nitrate and aluminum sulfate. The molar ratio of magnesium to aluminum in the aqueous solution of magnesium salt and aluminum salt is 3-5:

1.

2. The preparation method according to claim 1, characterized in that, In step S1, the alkaline aqueous solution is an aqueous solution of at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate, and the pH of the alkaline aqueous solution is 12-13; in step S2, the silicon source is selected from one or two of tetraethyl silicate and tetramethyl silicate. The ratio of the amount of graphene oxide, sodium dodecyl sulfate, sec-butylamine, alkaline aqueous solution, and silicon source in step S1 to that in step S2 is 0.3-0.5:0.4-0.6:0.05-0.15:100:1-2, in g:g:g:mL:mL.

3. The preparation method according to claim 1, characterized in that, In step S2, the addition of the silicon source and the metal salt solution specifically involves adding the silicon source and the metal salt solution dropwise to the precursor solution while stirring; the concentration of aluminum ions in the metal salt solution is 83-125 mmol / L; and the volume ratio of the silicon source to the metal salt solution is 1-2:0.

2.

4. The preparation method according to claim 1, characterized in that, In step S2, the dropping rates of the silicon source and the metal salt solution are: silicon source 0.05-0.2 mL / min, metal salt solution 0.05-0.2 mL / min.

5. The preparation method according to claim 1, characterized in that, In step S2, the reaction time is 2-4 hours.

6. The preparation method according to claim 1, characterized in that, In step S2, the post-processing includes the following steps: Centrifuge to collect the precipitate, wash it 1-3 times with cyclohexane, 1-3 times with ethanol, and 1-3 times with water, and then dry it.

7. The composite material prepared by the preparation method according to any one of claims 1-6.

8. The application of the composite material according to claim 7 in reducing 3-chloropropanol esters and glycidyl esters in diglyceride edible oils.

9. The application according to claim 8, characterized in that, Includes the following steps: The crude edible oil containing diglycerides and the composite material are added to a fluidized bed for adsorption and separation to obtain the treated edible oil containing diglycerides.

10. The application according to claim 9, characterized in that, The volume ratio of the crude edible oil containing diglycerides to the weight of the composite material is 1:0.1-10, in L:g. The adsorption temperature is 60-70℃, the adsorption fluidization rate is 0.2-1m / s, and the adsorption time is 20-40min.

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