Preparation method of modified mesoporous silica for removing toxins and heavy metals in corn oil

Abstract

The invention discloses a preparation method of modified mesoporous silica for removing toxins and heavy metals in corn oil, which comprises the following steps: preparing mesoporous silica with a proper aperture by using rice husk as a raw material and optimizing the use of a pore-enlarging agent, and carrying out synergistic modification with octyl and sulfydryl to obtain the modified mesoporous silica. The finally prepared modified mesoporous silica has a good adsorption effect on four common toxins AFB1, ZEN, OTA and DON in the corn oil, meanwhile, the modified mesoporous silica prepared by the method can also have a good adsorption effect on heavy metal ions in the corn oil, and the corn oil can be used for preparing the corn oil. The modified mesoporous silica can adsorb various toxins and heavy metal ions at the same time, and has a good application prospect.

Description

Technical Field

[0001] The invention relates to a preparation method of modified mesoporous silica for removing toxins and heavy metals from corn oil, and belongs to the field of fine inorganic chemical industry and food pollution control. Background Art

[0002] Corn production is second only to rice and wheat in China's food crops, and has made important contributions to ensuring national food security and food safety. In addition to being an important food crop, corn is also an important feed crop. Nearly 65% ​​of the world's corn is used as feed. Mycotoxins are byproducts of the secondary metabolism of filamentous fungi and are widely present in nature. Most mycotoxins have carcinogenic, teratogenic and mutagenic effects, and they can cause serious harm to human health when they enter the human body through the food chain. So far, nearly 400 mycotoxins have been discovered, among which the most harmful and polluting mycotoxins include aflatoxin B1 (AFB1), zearalenone (ZEN), ochratoxin A (OTA), and vomitoxin (DON).

[0003] In addition to mycotoxins, heavy metals are also common pollutants in corn, mainly including lead (Pb), cadmium (Cd), arsenic (As), mercury (Hg), chromium (Cr) and copper (Cu). Among these heavy metals, cadmium (Cd) is generally considered to be one of the most important heavy metal toxins because it is highly mobile in the environment, easily absorbed by plants and accumulated in the food chain. Cadmium pollution poses a major threat to human health, and long-term intake can lead to kidney damage and other health problems. In addition, the pollution level of lead (Pb) is also high, especially in some lead-zinc mining areas, where the lead exceeding the standard rate has reached 34.78%.

[0004] US 2004 / 0028678 A1 describes the use of acid-activated layered silicates to adsorb aflatoxins, ochratoxins, fumonisins, zearalenone, vomitoxin, T-2 toxin and ergotamine. This method can effectively improve the adsorption effect of layered silicates on aflatoxins and ochratoxins, but the adsorption effect on zearalenone and vomitoxin is very limited.

[0005] WO2017 / 221079A1 uses long-chain quaternary amines without polar groups (for example, dioctadecyltrimethylamine, octadecyltrimethylamine, octadecyldimethylamine, dodecylamine and similar compounds) to modify organic silicates, which has a good adsorption effect on aflatoxin and zearalenone, but has a poor effect on vomitoxin.

[0006] CN 116459792 A discloses a mycotoxin adsorbent, which has good adsorption properties for vomitoxin, aflatoxin B1 and zearalenone, but does not mention the adsorption effect of ochratoxin A; and the mycotoxin adsorbent has reduced adsorption effect on metals.

[0007] CN106111071A discloses a mercapto-modified magnetic mesoporous SiO2 for reducing heavy metal cadmium in wastewater. 2 However, the preparation method disclosed is for eliminating heavy metal cadmium in water. When the inventor tried to apply it to adsorb heavy metals in oil systems, the effect was not ideal, and the adsorption effect of toxins in the oil system was also not ideal.

[0008] CN109663572A discloses a method for preparing amino- and mercapto-bifunctionalized mesoporous silica and its application in arsenic removal, but it is also used to remove arsenic in water and does not disclose the effect of adsorbing heavy metals and toxins in oil systems.

[0009] Rice husk is a huge byproduct of rice processing, with an annual output of about 40 million tons. It contains a large amount of amorphous silicon dioxide (SiO 2 ) (>20%), it can be converted into mesoporous SiO after calcination, alkali dissolution and aging. 2 Through transmission electron microscopy, it was found that the mesoporous SiO 2 It has a highly regular, ordered and porous amorphous hexagonal structure. 2 It has many advantages such as large specific surface area, regular pore structure, and abundant surface active sites. The research team previously studied the use of magnetic mesoporous silica as an adsorption material to remove aflatoxin B1 from oil. 1 The adsorption effect is mainly achieved through hydrogen bonding, hydrophobic interaction and van der Waals force. 3 O 4 Nanoparticles can bind to aflatoxin B 1 The β-dicarbonyl of aflatoxin B can be chelated 1 Double fixed physical adsorption. Although the magnetic mesoporous silica prepared by rice husk is used to absorb aflatoxin B 1 It has a good adsorption effect, but the effect needs to be improved when it comes to the adsorption of other toxins and heavy metal ions. Summary of the invention

[0010] In order to solve the above problems, the present invention provides a modified mesoporous silica for removing toxins from corn oil. The prepared modified mesoporous silica has a high activity against four common toxins AFB in corn oil. 1, ZEN, OTA and DON, all have good adsorption effects. At the same time, the modified mesoporous silica prepared by the present invention can also have a good adsorption effect on heavy metal ions in corn oil. The modified mesoporous silica of the present invention can simultaneously adsorb multiple toxins and heavy metal ions, and has good application prospects.

[0011] The first object of the present invention is to provide a method for preparing modified mesoporous silica for removing toxins from corn oil, comprising the following steps: S1, crushing and calcining rice husks to obtain rice husk ash, and dissolving the rice husk ash with alkali to obtain a rice husk ash solution; S2, prepare a pore expander solution, add the rice husk ash solution prepared in step S1 to the pore expander solution at a volume ratio of 1:1-3, adjust the pH to 10.0-12.0, stir and react at 70-100°C for 1-4 hours, age at a constant temperature, centrifuge and discard the supernatant, wash the precipitate and dry it, and calcine at 500-600°C for 1-3 hours to obtain mesoporous silica; wherein the pore expander solution is a hexadecyltrimethylammonium bromide / polyacrylic acid aqueous solution, the concentration of hexadecyltrimethylammonium bromide is 0.02-0.04 mol / L, and the concentration of polyacrylic acid is 0.02-0.04 mol / L; S3, dispersing the mesoporous silica prepared in step S2 in toluene to obtain a mesoporous silica toluene solution; uniformly mixing octyltrimethoxysilane and methanol aqueous solution to obtain octyltrimethoxysilane methanol aqueous solution; then adding the octyltrimethoxysilane methanol aqueous solution to the mesoporous silica toluene solution according to the mass volume ratio of mesoporous silica to octyltrimethoxysilane of 1g:0.8~1.2mL, stirring the reaction at 70~80℃ for 20~30h, washing and drying the product to obtain octyl-modified mesoporous silica; S4. Disperse the octyl-modified mesoporous silica obtained in step S3 in anhydrous methanol, and then add glycerol for ultrasonic dispersion to obtain an octyl-modified mesoporous silica mixed solution; mix mercaptopropyltrimethoxysilane with anhydrous methanol to obtain a mercaptopropyltrimethoxysilane methanol solution; according to the mass volume ratio of octyl-modified mesoporous silica to octyltrimethoxysilane of 1g:0.8~1.2mL, add the mercaptopropyltrimethoxysilane methanol solution to the octyl-modified mesoporous silica mixed solution, add ammonia catalyst, stir the reaction at 70~90°C for 10~15h, wash and dry the product to obtain octylmercapto-modified mesoporous silica.

[0012] In one embodiment of the present invention, in step S1, calcination is performed at 500-600° C. for 4-6 h.

[0013] In one embodiment of the present invention, in step S1, the alkali dissolution of rice husk ash is performed by mixing sodium hydroxide and rice husk ash in a mass ratio of 4 to 6:4 and heating with water to dissolve the mixture.

[0014] In one embodiment of the present invention, the mesoporous silica toluene solution is obtained by mixing mesoporous silica and toluene at a mass volume ratio of 1 g:40-60 mL, and then ultrasonically dispersing the mixture at 30-50° C. for 20-40 min.

[0015] In one embodiment of the present invention, the methanol aqueous solution of octyltrimethoxysilane is obtained by mixing octyltrimethoxysilane and methanol aqueous solution in a volume ratio of 1:30-50 and ultrasonically treating for 20-40 min; wherein the methanol aqueous solution is methanol:water=85-95:10.

[0016] In one embodiment of the present invention, the octyl-modified mesoporous silica mixed solution is prepared by adding octyl-modified mesoporous silica to anhydrous methanol at a mass volume ratio of 1 g: 40-60 mL, ultrasonically dispersing the mixture for 20-40 min, then adding glycerol at a volume ratio of 1: 0.8-1.2, and ultrasonically treating the mixture for 20-30 min.

[0017] In one embodiment of the present invention, the methanol solution of mercaptopropyltrimethoxysilane is obtained by mixing mercaptopropyltrimethoxysilane and anhydrous methanol in a volume ratio of 1:20-40.

[0018] The second object of the present invention is to provide the preparation method for preparing modified mesoporous silica.

[0019] The third object of the present invention is to provide the use of the modified mesoporous silica in the removal of toxins and / or heavy metals from edible oils.

[0020] In one embodiment of the present invention, the edible oil is a mixture of one or more of corn oil, peanut oil and sunflower oil.

[0021] Beneficial effects of this application The present invention uses rice husk as raw material, optimizes the use of pore-enlarging agent, prepares mesoporous silica with suitable pore size, and then synergistically modifies it with octyl and thiol. The modified mesoporous silica finally prepared has good toxicity to four common toxins AFB in corn oil. 1 , ZEN, OTA and DON, all have good adsorption effects. At the same time, the modified mesoporous silica prepared by the present invention can also have a good adsorption effect on heavy metal ions in corn oil. The modified mesoporous silica of the present invention can simultaneously adsorb multiple toxins and heavy metal ions, and has good application prospects. DETAILED DESCRIPTION

[0022] The preferred embodiments of the present invention are described below. It should be understood that the embodiments are for better explaining the present invention and are not used to limit the present invention.

[0023] Detection method: The HPLC detection method of AFB1 can refer to "Luo Xiaohu, Wang Ren, Wang Li, Li Yongfu, Li Yanan, Zhou Yunyu, Zhu Lijun, Chen Zhengxing. Study on the effect and degradation kinetics of aflatoxin B1 in corn by ozone degradation [J]. Food Science, 2015, 36 (15): 45-49". Chromatographic column, C 18 Column (150×4.6 mm, 5 μm); fluorescence detector, excitation wavelength 360 nm, emission wavelength 460 nm; mobile phase, ultrapure water / methanol (chromatographic grade, 65 / 35, v / v); column temperature, 30°C; flow rate, 1.0 mL / min; injection volume, 10 μL.

[0024] The HPLC detection method of ZEN and OTA was referred to “Li Ke, Pan Lihong, Luo Xiaohu, Wang Li, Wang Ren, Xing Jiali, Du Zhihong, Sun Dongling, Chen Zhengxing. Simultaneous determination of zearalenone and ochratoxin A in cereals by HPLC[J]. Food Research and Development, 2020, 41(6): 118-123”. The chromatographic column was ZORBAX SB-aq column (150×4.6mm, 5 μm); the fluorescence detector was an excitation wavelength of 325 nm and an emission wavelength of 455 nm; the mobile phase composition was 2% acetic acid / acetonitrile / methanol (60 / 30 / 10, v / v / v); the column temperature was 30°C; the flow rate was 1.0 mL / min; the injection volume was 50 μL, and the elution time was 25 min.

[0025] The HPLC detection method of DON was based on “Li Ke, Pan Lihong, Luo Xiaohu, Wang Li, Wang Ren, Du Zhihong, Li Caiming, Chen Zhengxing. Degradation of zearalenone and vomitoxin in corn by electron beam irradiation [J]. Food and Fermentation Industries, 2019, 45(21): 73-78”. The chromatographic column was ZORBAX SB-aq column (150×4.6 mm, 5 μm); the UV detector wavelength was 218 nm; the mobile phase composition was acetonitrile / water (6 / 94, v / v); the column temperature was 30°C; and the flow rate was 0.9 mL / min.

[0026] The heavy metal ion concentration was detected by atomic absorption method, Cr 6+ The concentration is determined according to GB 5009.123-2023, Cd 2+ The concentration is determined according to GB 5009.15-2014, Pb 2+ The concentration determination shall refer to GB5009.12-2017.

[0027] Example 1: Preparation of octylthiol-modified mesoporous silica The steps for preparing octylthiol-modified mesoporous silica are as follows: (1) Preparation of rice husk-based mesoporous silica: Rice husk pretreatment: The washed rice husk was crushed and dried at 50°C for 24 hours. After the rice husk was fully carbonized, it was calcined at 550°C in a muffle furnace for 5 hours to obtain solid rice husk ash. Weigh and mix according to NaOH / rice husk ash = 5 / 4 (w / w), heat and dissolve with deionized water, and then adjust the volume to obtain a rice husk ash solution.

[0028] Mesoporous SiO 2 Synthesis: According to the concentration of hexadecyltrimethylammonium bromide (CTAB) and polyacrylic acid (PAA) being 0.02 mol / L, a hexadecyltrimethylammonium bromide (CTAB) / polyacrylic acid (PAA) aqueous solution was prepared, 100 mL of the solution was stirred and heated to 80°C, and then 50 mL of the pre-prepared rice husk ash solution was added, and the pH was adjusted to 11.0 with 1.0 mol / L HCl, and the temperature was maintained at 80°C and stirred for 2 h; after constant temperature aging for a certain period of time, the supernatant was discarded by centrifugation, washed with deionized water 3 times, dried at 50°C overnight, and calcined at 550°C for 2 h to obtain mesoporous SiO 2 Adsorbent material.

[0029] (2) Octyl modification Weigh 1.0 g of mesoporous silica and add it to 50 mL of toluene. Ultrasonic dispersion was performed at 40 °C for 30 min. 1.0 mL of octyltrimethoxysilane was mixed with 40 mL of methanol aqueous solution (methanol: water = 90:10) and ultrasonically treated for 30 min. Then, the mixture was poured into the above mesoporous silica toluene solution and stirred at 75 °C for 24 h. The obtained sample was separated and washed with methanol for 2 to 3 times. The sample was then dried at 80 °C for 12 h to obtain octyl-modified mesoporous silica.

[0030] (3) Mercapto modification Accurately weigh 1.0g of octyl-modified mesoporous silica, add 40mL of anhydrous methanol and ultrasonically disperse for 30min, then add 40mL of glycerol and ultrasonically disperse for another 30min. Mix 1.0mL of mercaptopropyltrimethoxysilane with 30mL of anhydrous methanol, pour into the above mixed solution, add 1mL of ammonia water, and stir at 80℃ for 12h. After the reaction is completed, pour out the residual liquid, wash it with methanol 2-4 times, wash it with water until it is neutral, and dry it at 80℃ for 12h to obtain octylmercapto-modified mesoporous silica.

[0031] Example 2 Preparation of octylthiol-modified mesoporous silica The steps for preparing octylthiol-modified mesoporous silica are as follows: (1) Preparation of rice husk-based mesoporous silica: Rice husk pretreatment: The washed rice husk is crushed and dried at 50°C for 24 hours. After the rice husk is fully carbonized, it is calcined at 500-600°C in a muffle furnace for 4-6 hours to obtain solid rice husk ash. Weigh and mix according to NaOH / rice husk ash = 5 / 4 (w / w), heat and dissolve with deionized water, and then adjust the volume to obtain a rice husk ash solution.

[0032] Mesoporous SiO 2 Synthesis: According to the concentration of hexadecyltrimethylammonium bromide (CTAB) of 0.02 mol / L and the concentration of polyacrylic acid (PAA) of 0.04 mol / L, a hexadecyltrimethylammonium bromide (CTAB) / polyacrylic acid (PAA) aqueous solution was prepared, 100 mL of the solution was stirred and heated to 80°C, and then 50 mL of the pre-prepared rice husk ash solution was added, and the pH was adjusted to 11.0 with 1.0 mol / L HCl, and the temperature was maintained at 80°C and stirred for 2 h; after constant temperature aging for a certain period of time, the supernatant was discarded by centrifugation, washed with deionized water 3 times, dried at 50°C overnight, and calcined at 550°C for 2 h to obtain mesoporous SiO 2 Adsorbent material.

[0033] (2) Octyl modification Weigh 1.0 g of mesoporous silica and add it to 50 mL of toluene. Ultrasonic dispersion was performed at 40 °C for 30 min. 1.2 mL of octyltrimethoxysilane was mixed with 40 mL of methanol aqueous solution (methanol: water = 90:10) and ultrasonically treated for 30 min. Then, the mixture was poured into the above mesoporous silica toluene solution and stirred at 75 °C for 24 h. The obtained sample was separated and washed with methanol for 2 to 3 times. The sample was then dried at 80 °C for 12 h to obtain octyl-modified mesoporous silica.

[0034] (3) Mercapto modification Accurately weigh 1.0g of octyl-modified mesoporous silica, add 40mL of anhydrous methanol and ultrasonically disperse for 30min, then add 40mL of glycerol and ultrasonically disperse for another 30min. Mix 0.8mL of mercaptopropyltrimethoxysilane with 30mL of anhydrous methanol, pour into the above mixed solution, add 1mL of ammonia water, and stir at 80℃ for 12h. After the reaction is completed, pour out the residual liquid, wash it with methanol 2-4 times, wash it with water until it is neutral, and dry it at 80℃ for 12h to obtain octylmercapto-modified mesoporous silica.

[0035] Example 3 Preparation of octylthiol-modified mesoporous silica The steps for preparing octylthiol-modified mesoporous silica are as follows: (1) Preparation of rice husk-based mesoporous silica: Rice husk pretreatment: The washed rice husk is crushed and dried at 50°C for 24 hours. After the rice husk is fully carbonized, it is calcined at 500-600°C in a muffle furnace for 4-6 hours to obtain solid rice husk ash. Weigh and mix according to NaOH / rice husk ash = 5 / 4 (w / w), heat and dissolve with deionized water, and then adjust the volume to obtain a rice husk ash solution.

[0036] Mesoporous SiO 2 Synthesis: According to the concentration of hexadecyltrimethylammonium bromide (CTAB) of 0.04 mol / L and the concentration of polyacrylic acid (PAA) of 0.02 mol / L, a hexadecyltrimethylammonium bromide (CTAB) / polyacrylic acid (PAA) aqueous solution was prepared, 100 mL of the solution was stirred and heated to 80°C, and then 50 mL of the pre-prepared rice husk ash solution was added, and the pH was adjusted to 11.0 with 1.0 mol / L HCl, and the temperature was maintained at 80°C and stirred for 2 h; after constant temperature aging for a certain period of time, the supernatant was discarded by centrifugation, washed with deionized water 3 times, dried at 50°C overnight, and calcined at 550°C for 2 h to obtain mesoporous SiO 2 Adsorbent material.

[0037] (2) Octyl modification Weigh 1.0 g of mesoporous silica and add it to 50 mL of toluene. Ultrasonic dispersion was performed at 40 °C for 30 min. 0.8 mL of octyltrimethoxysilane was mixed with 40 mL of methanol aqueous solution (methanol: water = 90:10) and ultrasonically treated for 30 min. Then, the mixture was poured into the above mesoporous silica toluene solution and stirred at 75 °C for 24 h. The obtained sample was separated and washed with methanol for 2 to 3 times. The sample was then dried at 80 °C for 12 h to obtain octyl-modified mesoporous silica.

[0038] (3) Mercapto modification Accurately weigh 1.0g of octyl-modified mesoporous silica, add 40mL of anhydrous methanol and ultrasonically disperse for 30min, then add 40mL of glycerol and ultrasonically disperse for another 30min. Mix 1.2mL of mercaptopropyltrimethoxysilane with 30mL of anhydrous methanol, pour into the above mixed solution, add 1mL of ammonia water, and stir at 80℃ for 12h. After the reaction is completed, pour out the residual liquid, wash it with methanol 2-4 times, wash it with water until it is neutral, and dry it at 80℃ for 12h to obtain octylmercapto-modified mesoporous silica.

[0039] Comparative Example 1: No Octyl Modification On the basis of Example 1, step (2) was omitted to prepare mercapto-modified mesoporous silica.

[0040] Comparative Example 2: No thiol modification Based on Example 1, step (3) was omitted to prepare octyl-modified mesoporous silica.

[0041] Comparative Example 3: Changing the modification ratio of octyl and thiol On the basis of Example 1, the amount of octyltrimethoxysilane in step (2) was adjusted to 2.0 mL, and the amount of mercaptopropyltrimethoxysilane in step (3) was adjusted to 0.5 mL. The remaining steps were consistent with Example 1 to prepare octylmercapto-modified mesoporous silica.

[0042] Comparative Example 4: Changing the modification ratio of octyl and thiol On the basis of Example 1, the amount of octyltrimethoxysilane in step (2) was adjusted to 0.5 mL, and the amount of mercaptopropyltrimethoxysilane in step (3) was adjusted to 2.0 mL. The remaining steps were consistent with Example 1 to prepare octylmercapto-modified mesoporous silica.

[0043] Comparative Example 5: Mesoporous Silica without Octyl and Mercapto Modification On the basis of Example 1, steps (2) and (3) were deleted, and the remaining steps were the same as those in Example 1 to prepare unmodified mesoporous silica.

[0044] Comparative Example 6: Using dodecyltrimethoxysilane On the basis of Example 1, octyltrimethoxysilane in step (2) was replaced by dodecyltrimethoxysilane, and the remaining steps were consistent with Example 1 to prepare dodecylmercapto-modified mesoporous silica.

[0045] Comparative Example 7: Changing the proportion of the pore-enlarging agent Based on Example 1, in step (1), the mesoporous SiO 2 During the synthesis, a hexadecyltrimethylammonium bromide (CTAB) / polyacrylic acid (PAA) aqueous solution was prepared according to a hexadecyltrimethylammonium bromide (CTAB) concentration of 0.01 mol / L and a polyacrylic acid (PAA) concentration of 0.05 mol / L. The remaining steps were consistent with Example 1 to prepare octylthiol-modified mesoporous silica.

[0046] Comparative Example 8: Changing the proportion of the pore-enlarging agent On the basis of Example 1, in step (1), when synthesizing mesoporous SiO2, the concentration of cetyltrimethylammonium bromide (CTAB) is 0.05 mol / L, and the concentration of polyacrylic acid (PAA) is 0.01 mol / L, and a cetyltrimethylammonium bromide (CTAB) / polyacrylic acid (PAA) aqueous solution is prepared. The remaining steps are consistent with Example 1 to prepare octylmercapto-modified mesoporous silica.

[0047] Example 4: Detection of detoxification effect The octylmercapto-modified mesoporous silica prepared in Examples 1, 2, and 3 and the materials prepared in Comparative Examples 1 to 8 were used to test the detoxification effects: (1) Adsorption experiment of toxins in edible oil Preparation of toxin AFB 1 , ZEN, OTA and DON were contaminated with edible oil with an initial concentration of 1.2 μg / mL. 10 mL was taken in different sample bottles, and 10 mg of adsorbent material (Examples 1 to 3, Comparative Examples 1 to 8) was added to each bottle and placed in a shaker. The mixture was shaken at a constant temperature of 20 °C at a speed of 150 r / min for 5 hours of adsorption. The supernatant of the edible oil was centrifuged and the toxins in the edible oil were extracted by adding an extracting solution of acetonitrile / water (84 / 16, v / v). The toxin content in the extract was determined by high performance liquid chromatography, and the residual toxin content was calculated to calculate the adsorption rate of the adsorbent material on the toxins in the oil, and the adsorption effect of the adsorbent material on the toxins in the oil was investigated. Among them, the calculation formula for the adsorption rate of toxins is as follows:

[0048] (2) Adsorption experiment of heavy metal ions in edible oil Prepare edible oils with an initial concentration of 1.50 mg / L of chromium, cadmium, and lead, respectively. Take 10 mL of each oil in different sample bottles, add 10 mg of adsorption material (Examples 1-3, Comparative Examples 1-8) and place them in a shaker. Keep the temperature at 30 °C at an initial pH of 5. o C adsorption for 6 h, the concentration of heavy metal ions in the edible oil after adsorption was completed was determined, the adsorption rate of the adsorbent material on the heavy metal ions in the oil was calculated, and the adsorption effect of the adsorbent material on the heavy metal ions in the oil was investigated. Among them, the calculation formula for the adsorption rate of heavy metal ions is as follows:

[0049] or is the adsorption rate, %; C o is the initial concentration of heavy metal ion standard solution, mg / L; C e is the heavy metal ion concentration of the solution after adsorption, mg / L.

[0050] The adsorption rates of toxins and heavy metal ions are shown in Table 1.

[0051] Table 1 Detoxification effect

[0052] From the data in Table 1, it can be seen that when octyl and thiol are used for collaborative modification, the adsorption effect of several toxins and heavy metal ions can be better; when only octyl is used for modification, the metal ion adsorption effect is better, but the adsorption effect of toxins is poor, and when only thiol is used for modification, the adsorption effect of metal ions and toxins in the oil system is not very good due to the enhanced hydrophilicity of the entire material. By comparing Comparative Example 6 with Example 1, it can be seen that when octyl modification is replaced by dodecyl modification, the adsorption of toxins is weaker, and the adsorption effect of metal ions is not as good as that of octyl modification.

[0053] In addition, the present invention also optimizes the ratio of the pore-enlarging agent, and the pore size of the mesoporous silica prepared by the method of the present invention is coordinated with the synergistic modification of the mercapto group and the octyl group, so that the finally prepared octylthiol-modified mesoporous silica can simultaneously 1 , ZEN, OTA and DON have good adsorption properties, and can also better adsorb heavy metal ions in the oil system.

[0054] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Anyone familiar with this technology can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the definition of the claims.

Claims

1. A method for preparing modified mesoporous silica for removing toxins and heavy metals from corn oil, characterized in that: The steps include: S1, crushing and calcining rice husks to obtain rice husk ash, and dissolving the rice husk ash with alkali to obtain a rice husk ash solution; S2, prepare a pore expander solution, add the rice husk ash solution prepared in step S1 to the pore expander solution at a volume ratio of 1:1-3, adjust the pH to 10.0-12.0, stir and react at 70-100°C for 1-4 hours, age at a constant temperature, centrifuge and discard the supernatant, wash the precipitate and dry it, and calcine at 500-600°C for 1-3 hours to obtain mesoporous silica; wherein the pore expander solution is a hexadecyltrimethylammonium bromide / polyacrylic acid aqueous solution, the concentration of hexadecyltrimethylammonium bromide is 0.02-0.04 mol / L, and the concentration of polyacrylic acid is 0.02-0.04 mol / L; S3, dispersing the mesoporous silica prepared in step S2 in toluene to obtain a mesoporous silica toluene solution; uniformly mixing octyltrimethoxysilane and methanol aqueous solution to obtain octyltrimethoxysilane methanol aqueous solution; then adding the octyltrimethoxysilane methanol aqueous solution to the mesoporous silica toluene solution according to the mass volume ratio of mesoporous silica to octyltrimethoxysilane of 1g:0.8~1.2mL, stirring the reaction at 70~80℃ for 20~30h, washing and drying the product to obtain octyl-modified mesoporous silica; S4. Disperse the octyl-modified mesoporous silica obtained in step S3 in anhydrous methanol, and then add glycerol for ultrasonic dispersion to obtain an octyl-modified mesoporous silica mixed solution; mix mercaptopropyltrimethoxysilane with anhydrous methanol to obtain a mercaptopropyltrimethoxysilane methanol solution; according to the mass volume ratio of octyl-modified mesoporous silica to octyltrimethoxysilane of 1g:0.8~1.2mL, add the mercaptopropyltrimethoxysilane methanol solution to the octyl-modified mesoporous silica mixed solution, add ammonia catalyst, stir the reaction at 70~90°C for 10~15h, wash and dry the product to obtain octylmercapto-modified mesoporous silica.

2. The preparation method according to claim 1, characterized in that: In step S1, calcination is performed at 500-600°C for 4-6 h.

3. The preparation method according to claim 1, characterized in that: In step S1, the alkali dissolution of rice husk ash is performed by mixing sodium hydroxide and rice husk ash in a mass ratio of 4 to 6:4 and heating with water to dissolve the mixture.

4. The preparation method according to claim 1, characterized in that The mesoporous silica toluene solution is obtained by mixing mesoporous silica and toluene in a mass volume ratio of 1 g:40-60 mL, and then ultrasonically dispersing the mixture at 30-50° C. for 20-40 min.

5. The preparation method according to claim 1, characterized in that The methanol aqueous solution of octyltrimethoxysilane is obtained by mixing octyltrimethoxysilane and methanol aqueous solution in a volume ratio of 1:30-50 and ultrasonically treating for 20-40 min; wherein the methanol aqueous solution is methanol:water=85-95:

10.

6. The preparation method according to claim 1, characterized in that The octyl-modified mesoporous silica mixed solution is prepared by adding octyl-modified mesoporous silica to anhydrous methanol at a mass volume ratio of 1 g: 40-60 mL, ultrasonically dispersing the mixture for 20-40 min, then adding glycerol at a volume ratio of 1: 0.8-1.2, and ultrasonically treating the mixture for 20-30 min.

7. The preparation method according to claim 1, characterized in that: The mercaptopropyltrimethoxysilane methanol solution is obtained by mixing mercaptopropyltrimethoxysilane and anhydrous methanol in a volume ratio of 1:20-40.

8. A modified mesoporous silica prepared by the preparation method according to any one of claims 1 to 7.

9. Use of the modified mesoporous silica according to claim 8 in removing toxins and / or heavy metals from edible oils.

10. The use according to claim 9, characterized in that: The edible oil is a mixture of one or more of corn oil, peanut oil and sunflower oil.

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