Mycotoxin adsorbent, its preparation method and application

Abstract

The present invention relates to the field of adsorbents, and discloses a mycotoxin adsorbent, its preparation method and application. The method includes: (1) providing a slurry containing montmorillonite and sodium lignosulfonate, wherein the particle size of the slurry satisfies D(4,3)≤5 μm; (2) mixing the slurry in step (1) with activated carbon, and controlling the mixture to be acidic, and obtaining a solid-phase material after post-treatment; (3) calcining the solid-phase material in step (2). The adsorbent has significantly better adsorption effect on vomitoxin, and can also ensure good adsorption capacity for aflatoxin, zearalenone, etc. At the same time, it has low adsorption of nutrients, high adsorption selectivity and good safety, and is particularly suitable for feed processing. The preparation method has high controllability and a simple process, which is more conducive to industrial production.

Description

Technical Field

[0001] The present invention relates to the field of adsorbents, and particularly to an adsorbent, a preparation method thereof, and an application thereof. Background Art

[0002] The contamination of feed and food by mycotoxins is a major global issue. It is estimated that approximately one - quarter of the world's annual crop production is contaminated by mycotoxins. Mycotoxins are widely distributed and highly harmful. They not only have adverse effects on crops, animals, and humans, leading to a decline in the nutritional value of crops and feed, and damage to the life and health of humans and animals, but also result in an increase in livestock production, veterinary care, hygiene care costs, as well as management and research costs. Mold growth occurs during all growth stages of plants and food crops are susceptible to mold infection during harvesting, storage, processing, transportation, and sales.

[0003] Mycotoxins are produced by many fungal species, mainly including Aspergillus, Penicillium, Alternaria, Fusarium, and Claviceps. In recent years, more than 500 mycotoxins from these fungi and other fungi have been identified. The research on mycotoxins mainly focuses on several common mycotoxins that have been proven to be toxic to humans and animals. Internationally, major attention is paid to several mycotoxins that have a significant impact on human and animal health and the economy, including Aflatoxin (AFT), Ochratoxin A (OTA), Fumonisins (FBs), Zearalenone (ZEN), Patulin (PAT), Nivalenol (NIV), Citrinin (CTN), and deoxynivalenol.

[0004] There are many kinds of mycotoxins. Among them, deoxynivalenol (DON), a type B toxin in the trichothecene group mainly produced by the genus Fusarium (Fusarium spp.), is one of the most seriously contaminated mycotoxins in wheat and its products in China. Because it can cause feed rejection behavior and vomiting in pigs, deoxynivalenol is named vomitoxin. It mainly contaminates corn, wheat, and barley, and also contaminates crops such as potatoes. Globally, the economic losses caused by vomitoxin-contaminated crops reach up to billions of dollars every year. Vomitoxin contamination not only reduces the feeding value of feed but also affects the growth performance of animals, damages the immune system of animals, and leads to the occurrence of diseases. Vomitoxin has high chemical stability, which makes it difficult to be destroyed or eliminated during feed storage and processing, posing a potential threat to the health of humans and animals. Therefore, it is particularly important to explore the detoxification methods of vomitoxin.

[0005] The detoxification of vomitoxin can be roughly divided into three methods: physical, chemical, and biological, according to the differences in their action principles. Physical detoxification aims at adsorption and separation, chemical detoxification uses chemical substances to change the molecular structure of vomitoxin, and biological detoxification mainly refers to the adsorption and biodegradation of microorganisms. Currently, the widely used method in production is the use of mycotoxin adsorbents.

[0006] 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 improvement of the adsorption effect on zearalenone and vomitoxin is very limited.

[0007] US 2012 / 0070516 discloses a novel adsorbent composed of partially or wholly plant lignocellulosic biomass or separated biomass components, which can bind a variety of mycotoxins, including difficult-to-bind mycotoxins such as ochratoxin A, T-2, and vomitoxin. Lignocellulose has a low adsorption efficiency for toxins and requires a large dosage. WO 2015 / 075686 provides an adsorbent of the organoaluminosilicate type, which uses a quaternary ammonium group functionalized with an ethoxylated alkylphenol chain, or more specifically, a derivative of ethoxylated nonylphenol. The derived mycotoxin adsorbent has a good adsorption effect on the toxic effect of vomitoxin, but the safety of the quaternary ammonium salt functionalized with an ethoxylated alkylphenol chain remains to be verified.

[0008] WO2017 / 221079A1 modifies organosilicates with long-chain quaternary amines without polar groups (such as octacosyltrimethylamine, octadecyltrimethylamine, octadecyldimethylamine, dodecylamine and similar compounds), which has a good adsorption effect on aflatoxin and zearalenone, but has a poor effect on vomitoxin.

[0009] Shawna L. Lemke et al. "Study on the detoxification of organophilic montmorillonite in zearalenone-contaminated diets by mouse uterine weight bioassay" prepared an adsorbent by modifying montmorillonite with cetyltrimethylammonium and cetylamine, indicating that it has a good adsorption effect on ZEN. However, it was found that it did not effectively protect the uterus from the toxin, and the modified montmorillonite also caused a final weight loss. The authors believe that it may be that the organic compound desorbs from the clay in the body and interacts with the gastrointestinal membrane in the body, thus increasing the uptake of ZEN. In addition to the enhanced toxicity of ZEN contamination, the addition of feed and organophilic clay led to anorexia and a decrease in weight gain in mice. (Shawna L. Lemke, Kittane Mayura, William R. Reeves, Naisyin Wang, Christie Fickey & Timothy D. Phillips (2001) Investigation of Organophilic Montmorillonite Clay Inclusion in Zearalenone-Contaminated Diets Using the Mouse Uterine Weight Bioassay, Journal of Toxicology and Environmental Health, Part A: Current Issues, 62:4, 243-258) Thus, long fatty chain alkyl quaternary ammonium salt clay surface modifiers have certain toxicity, and there are great potential safety hazards in their application in the aquaculture industry.

[0010] Activated carbon has the characteristics of a large surface area and strong adsorption capacity, and has a strong adsorption capacity for various toxins and other substances. In order to improve the adsorption effect of mycotoxin adsorbents on vomitoxin, researchers compounded carbon substances such as activated carbon with clay minerals to synergistically enhance the effect.

[0011] US 2012 / 0219683 describes a mycotoxin adsorbent containing clay and activated carbon to solve the problem of mycotoxin contamination in food, which has a good effect on vomitoxin and T-2 toxin. Since the adsorption of activated carbon is not selective, it will first adsorb other nutrient elements and trace elements with a large amount during use, which will reduce its adsorption effect on toxins and at the same time reduce the utilization rate of nutrients.

[0012] CN103521181A discloses a composite mycotoxin adsorbent, which is composed of 20-80% high-purity montmorillonite, 0-40% surface-modified montmorillonite, and 0-40% carbon-coated montmorillonite. The surface-modified montmorillonite is prepared by modifying with a long-chain fatty alkyl quaternary ammonium salt or a non-ionic compound as a surface modifier. The carbon-coated montmorillonite is obtained by acidifying a carbon source material (coconut shell powder, bamboo powder, and wood powder) with hydrochloric acid or sulfuric acid at a concentration of 30-60%, washing and dehydrating to obtain an acidified thick slurry, acidifying high-purity montmorillonite with hydrochloric acid or sulfuric acid at a concentration of 5-20%, washing and dehydrating to obtain an acidified montmorillonite thick slurry, mixing the two slurries evenly, and then calcining and activating at a high temperature of 500-700°C. This method first activates and then carbonizes the carbon source material, resulting in a lower specific surface area of the product. During the carbonization process, the temperature is too high (reaching 700°C) and there is no requirement to carry out the process under an air-free or protective atmosphere, which may cause the loss of the coated carbon due to oxidation and failure, and reduce the adsorption rate.

[0013] Among the existing adsorbent products, the adsorption effect on vomitoxin in mycotoxins is poor. Studying a safe, effective mycotoxin adsorbent that has no adsorption effect on drugs and other nutrients, especially an adsorbent for the problem of vomitoxin pollution, is a meaningful research topic with application prospects. In this field, this problem has not been solved theoretically and practically, and alternative solutions are still needed to solve the problem of mycotoxin pollution in animal feed, especially the problem of vomitoxin pollution. Therefore, how to make the adsorbent have a better adsorption effect on vomitoxin and make the adsorbent have high safety and good selective adsorption ability is the core key to developing an adsorbent for mycotoxins. Summary of the Invention

[0014] The purpose of the present invention is to overcome the above-mentioned problem of poor selectivity of the adsorbent for mycotoxins existing in the prior art, and to provide an adsorbent, its preparation method and application. The adsorbent has high adsorption performance for mycotoxins, especially for vomitoxin, can show a good adsorption effect, has low adsorption of nutrients, has obvious adsorption selectivity, good safety, and is especially suitable for feed processing. The preparation method has high controllability and a simple process, and is more conducive to industrial production.

[0015] To achieve the above purpose, the first aspect of the present invention provides a preparation method of an adsorbent, which includes:

[0016] (1) Providing a slurry containing montmorillonite and sodium lignosulfonate, and the particle size of the slurry satisfies D(4,3) ≤ 5 μm;

[0017] (2) Mixing the slurry in step (1) with activated carbon, controlling the mixture to be acidic, and obtaining a solid-phase material through post-treatment;

[0018] (3) Calcine the solid-phase material obtained in step (2).

[0019] The second aspect of the present invention provides an adsorbent prepared by the method described above.

[0020] The third aspect of the present invention provides the application of the adsorbent described above in removing mycotoxins.

[0021] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0022] 1. The adsorbent provided by the present invention has good adsorption performance for mycotoxins (including vomitoxin, aflatoxin B1, zearalenone, etc.). In particular, for vomitoxin which is still difficult to solve with existing adsorbent products, the adsorbent provided by the present invention can show good adsorption effect. The adsorbent provided by the present invention can ensure good adsorption effect for aflatoxin and zearalenone, etc. while significantly improving the adsorption effect on vomitoxin. Moreover, the adsorbent provided by the present invention can also reduce the adsorption of nutrients (including amino acids such as lysine, and nutrient elements such as copper, selenium, and zinc, etc.), effectively solving the problem that existing mycotoxin adsorbents such as activated carbon do not have selectivity, and has higher safety.

[0023] 2. The method provided by the present invention has high controllability and a simple process, which is more conducive to industrial production.

[0024] 3. The adsorbent provided by the present invention is green and safe. The sodium lignosulfonate used in the product can be used in feed processing. Under acidic conditions, it forms a precipitate and forms a stable complex with montmorillonite and activated carbon, and has no toxic and side effects. Detailed Embodiments

[0025] The endpoints and any values disclosed herein are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of each range, between the endpoint values of each range, between the endpoint value of each range and a single point value, and between single point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0026] In the first aspect, the present invention provides a method for preparing an adsorbent, which method comprises:

[0027] (1) Provide a slurry containing montmorillonite and sodium lignosulfonate, wherein the particle size of the slurry satisfies D(4,3) ≤ 5 μm;

[0028] (2) Mix the slurry obtained in step (1) with activated carbon, and control the mixed material to be acidic, and obtain a solid-phase material after post-treatment;

[0029] (3) Calcine the solid-phase material obtained in step (2).

[0030] Among them, D(4,3) refers to the volume 4th moment average particle size of the particles, and a laser particle size analyzer can be used to detect the particle size.

[0031] The inventors of the present invention found in the research that, according to the above method, an adsorbent with a structure of montmorillonite-coated carbon can be prepared. The structure of the adsorbent is stable, and the adsorbent has a weak water swelling performance and is relatively stable in the digestive tract structure. The obtained adsorbent has a high adsorption capacity for mycotoxins and can also reduce the adsorption of nutrients. Compared with the existing activated carbon-based adsorbents for adsorbing mycotoxins, it has obvious selectivity. In particular, the existing adsorbents have a poor adsorption effect on vomitoxin, while the adsorbent provided by the present invention can obtain significantly better effects on vomitoxin and can also ensure good adsorption effects on aflatoxin and zearalenone at the same time. The materials used in the preparation process can be used for feed processing, are safe and non-toxic, and are more suitable for industrial production.

[0032] According to the present invention, preferably, the slurry further includes a dispersion solvent. The dispersion solvent is used to fully and uniformly disperse montmorillonite and sodium lignosulfonate.

[0033] According to the present invention, preferably, the dispersion solvent is water.

[0034] According to the present invention, preferably, the dosage of the dispersion solvent is 6-18 g relative to each gram of montmorillonite (for example, it can be 6 g, 7 g, 8 g, 9 g, 10 g, 11 g, 12 g, 13 g, 14 g, 15 g, 16 g, 17 g, 18 g, and values within the range formed by any two of the above values).

[0035] According to the present invention, preferably, the dosage of sodium lignosulfonate is 2-25 g relative to 100 g of montmorillonite, and more preferably 5-22 g (for example, it can be 5 g, 6 g, 7 g, 8 g, 9 g, 10 g, 11 g, 12 g, 13 g, 14 g, 15 g, 16 g, 17 g, 18 g, 19 g, 20 g, 21 g, 22 g, and values within the range formed by any two of the above values).

[0036] It is understood that lignin is a class of organic polymers that are widely distributed in higher plants above ferns with vascular bundles. Classified by monomer composition, lignin mainly includes three types. One is S-lignin, that is, syringyl lignin polymerized from syringyl propane structural monomers; another is G-lignin, that is, guaiacyl lignin polymerized from guaiacyl propane structural monomers; and the other is H-lignin, that is, p-hydroxyphenyl lignin polymerized from p-hydroxyphenyl propane structural monomers. The sodium lignosulfonate is also a kind of polymer. Due to different molecular weights or sources of lignin, there are also various sodium lignosulfonates. In the present invention, there is no particular limitation on the molecular weight of the sodium lignosulfonate and the source of lignin therein. Preferably, however, the weight-average molecular weight of the sodium lignosulfonate is 3000-10000 g / mol. For example, sodium lignosulfonate of model ARBO N18 purchased from Shanghai Waidian International Trade Co., Ltd. can be selected, and its molecular weight is 6000-8000 g / mol.

[0037] There is also no particular limitation on the specific form of use of montmorillonite, and various materials containing montmorillonite can be used. According to a particularly preferred embodiment of the present invention, the montmorillonite is provided in the form of bentonite. It is understood that bentonite is a non-metallic mineral mainly composed of montmorillonite. Generally, bentonite ore can be used, that is, calcium-based bentonite particles after drying in the sun. The weight content of montmorillonite in bentonite is preferably ≥80 wt%.

[0038] Among them, the method for obtaining the slurry is not particularly limited. Preferably, however, the method for obtaining the slurry includes: ball-milling montmorillonite and sodium lignosulfonate to make a slurry, and exfoliating the slurry so that the particle size of the slurry after exfoliation satisfies D(4,3)≤5 μm. Montmorillonite, sodium lignosulfonate and water can be input into a ball mill for pulping, and then the materials can be sieved to remove large-particle (particle size of 75 μm and above) impurities.

[0039] Among them, an ultrafine exfoliation device such as a vibration mill, a stirring mill, an exfoliator, a nano ball mill, a nano sand mill or a nano impact mill can be used for exfoliation.

[0040] According to a particularly preferred embodiment of the present invention, the particle size of the slurry after exfoliation satisfies D(4,3)≤2 μm. In this way, it can be further ensured that an adsorbent with a montmorillonite-coated carbon structure is obtained, and the stability of the structure is further ensured, and the selectivity of adsorption is further ensured.

[0041] According to the present invention, preferably, relative to 100 g of montmorillonite, the dosage of activated carbon is 1-25 g, more preferably 5-22 g (for example, it can be 5 g, 6 g, 7 g, 8 g, 9 g, 10 g, 11 g, 12 g, 13 g, 14 g, 15 g, 16 g, 17 g, 18 g, 19 g, 20 g, 21 g, 22 g and the ranges and values within the ranges formed by any two of the above values). In this way, the stability of the adsorbent structure can be further ensured, and the selectivity of the adsorbent for mycotoxins (including vomitoxin, aflatoxin, zearalenone, etc.) relative to nutrients can be further ensured.

[0042] According to the present invention, preferably, the specific surface area of the activated carbon is 800-1500 m 2 / g, preferably 900-1200 m 2 / g (for example, it can be 900 m 2 / g, 1000 m 2 / g, 1100 m 2 / g, 1200 m 2 / g and the ranges and values within the ranges formed by any two of the above values).

[0043] According to the present invention, the particle size of the activated carbon satisfies: D90≤45 μm, so that the montmorillonite lamellae can be effectively coated on the carbon surface. It can be understood that D90≤45 μm means that 90% of the particle size is less than or equal to 45 μm, and the detection method is a laser particle size analyzer.

[0044] According to the present invention, preferably, in step (2), the pH of the mixed material is controlled ≤5; more preferably, in step (2), the pH of the mixed material is controlled to be 3-4 (for example, it can be 3, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4 and the ranges and values within the ranges formed by any two of the above values). The inventors of the present invention further found in the research that by controlling the pH under the above conditions, an adsorbent with a montmorillonite-coated carbon structure can be further ensured to be obtained, and the stability of the structure is stronger. Sulfuric acid can be added to the material to achieve the above pH.

[0045] According to the present invention, preferably, the post-treatment method includes: washing the mixed material with water, dehydrating and drying it in sequence.

[0046] According to the present invention, preferably, the water washing makes the conductivity of the washed material ≤1800 S / m. Ceramic membrane equipment or filter press equipment can be used for water washing and dehydration. Drying can be carried out in a flash drying equipment or a spray drying equipment.

[0047] According to the present invention, preferably, the calcination temperature is 400 - 450 °C (for example, it can be 400 °C, 410 °C, 420 °C, 430 °C, 440 °C, 450 °C, and the ranges and values within the ranges formed by any two of the above values), and the time is 0.5 - 2 h (for example, it can be 0.5 h, 1 h, 1.5 h, 2 h, and the ranges and values within the ranges formed by any two of the above values). The inventors of the present invention further found in the research that under the above conditions, the binding force between montmorillonite and activated carbon in the adsorbent can be made stronger, the water swelling performance of the adsorbent is weaker, the structure is more stable in the digestive tract, and the adsorption effect on mycotoxins is better.

[0048] According to the present invention, preferably, the dehydration and drying make the water content in the material ≤ 10 wt%. The material can be dried in a flash drying device or a spray drying device.

[0049] In a second aspect, the present invention provides an adsorbent prepared by the method as described above.

[0050] Among them, the particle size of the adsorbent is not particularly limited, but preferably, the particle size of the adsorbent satisfies that D(4,3) is 75 - 200 μm (for example, it can be 75 μm, 76 μm, 77 μm, 78 μm, 79 μm, 80 μm, 81 μm, 82 μm, 85 μm, 88 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 150 μm, 180 μm, 190 μm, 200 μm, and the ranges and values within the ranges formed by any two of the above values).

[0051] In a third aspect, the present invention provides the application of the adsorbent as described above in removing mycotoxins.

[0052] Preferably, the mycotoxins include at least one of vomitoxin, aflatoxin (especially aflatoxin B1), and zearalenone.

[0053] Among them, the adsorbent provided by the present invention is particularly suitable for application in feed, and the adsorbent and feed can be mixed. The adsorbent is non-toxic to animals, and the ratio when it is mixed with feed is not particularly limited. For example, in the feed, 0.01 - 1 wt% of the adsorbent relative to the weight of the feed can be mixed in.

[0054] The present invention will be described in detail below through examples.

[0055] In the following examples and comparative examples:

[0056] In the bentonite ore, the content of montmorillonite is 92.8 wt%, and the water content is 7.1 wt%;

[0057] Sodium lignosulfonate was purchased from Shanghai Waidian International Trade Co., Ltd., with the model of ARBO N18, and its weight-average molecular weight was 6000 - 8000 g / mol.

[0058] Example 1

[0059] (1) 5000 kg of calcium-based bentonite ore, 500 kg of sodium lignosulfonate, and 45000 kg of water were evenly input into a ball mill for grinding and pulping. Then the material was sieved to remove large particle impurities with a particle size of 75 μm and above.

[0060] (2) The sieved slurry was input into an ultrafine delaminator for grinding and delaminating until D(4,3) was 1.1 μm.

[0061] (3) 500 kg of activated carbon powder with a specific surface area of 1200 m 2 / g and a particle size D90 of 38.1 μm was added to the delaminated slurry and mixed evenly. Then sulfuric acid was added to adjust the pH value of the slurry to 4, and water washing, dehydration, and spray drying were carried out. Among them, the water washing was carried out until the conductivity of the washed slurry was 1200 S / m, and the water content in the material after spray drying was 7.9 wt%.

[0062] (4) The material was placed in a rotary kiln and calcined at 450 °C for 1 h to obtain adsorbent SD01 with a particle size D(4,3) of 77.3 μm.

[0063] Example 2

[0064] (1) 5000 kg of calcium-based bentonite ore, 250 kg of sodium lignosulfonate, and 30000 kg of water were evenly input into a ball mill for grinding and pulping. Then the material was sieved to remove large particle impurities with a particle size of 75 μm and above.

[0065] (2) The sieved slurry was input into an ultrafine delaminator for grinding and delaminating until D(4,3) was 2 μm.

[0066] (3) 250 kg of activated carbon powder with a specific surface area of 900 m 2 / g and a particle size D90 of 41.6 μm was added to the delaminated slurry and mixed evenly. Then sulfuric acid was added to adjust the pH value of the slurry to 3, and water washing, dehydration, and spray drying were carried out. Among them, the water washing was carried out until the conductivity of the washed slurry was 800 S / m, and the water content in the material after spray drying was 9.1 wt%.

[0067] (4) The material was placed in a rotary kiln and calcined at 450 °C for 1.5 h to obtain adsorbent SD02 with a particle size D(4,3) of 81.5 μm.

[0068] Example 3

[0069] (1) Input 5000 kg of calcium-based bentonite ore, 1000 kg of sodium lignosulfonate and 75000 kg of water into a ball mill for grinding and pulping. Then, screen the material to remove large particle impurities with a particle size of 75 μm and above.

[0070] (2) Input the screened slurry into an ultrafine delaminator for grinding and delamination until D(4,3) is 1.4 μm.

[0071] (3) Add 1000 kg of activated carbon powder with a specific surface area of 900 m 2 / g and a particle size D90 of 32.9 μm to the delaminated slurry, mix well, then add sulfuric acid to adjust the pH value of the slurry to 4, and perform water washing, dehydration and spray drying. Among them, wash until the conductivity of the washed slurry is 1500 S / m, and the water content in the material after spray drying is 8 wt%.

[0072] (4) Place the material in a rotary kiln and calcine it at 400 °C for 2 h to obtain adsorbent SD03 with a particle size D(4,3) of 79.5 μm.

[0073] Example 4

[0074] Prepare the adsorbent according to the method of Example 1, except that the dosage of sodium lignosulfonate is 100 kg. The prepared adsorbent is denoted as SD04 with a particle size D(4,3) of 86.4 μm.

[0075] Example 5

[0076] Prepare the adsorbent according to the method of Example 1, except that the dosage of activated carbon is 100 kg. The prepared adsorbent is denoted as SD05 with a particle size D(4,3) of 79.1 μm.

[0077] Example 6

[0078] Prepare the adsorbent according to the method of Example 1, except that the particle size of the slurry in the delaminated slurry satisfies D(4,3) of 4.8 μm. The prepared adsorbent is denoted as SD06 with a particle size D(4,3) of 79.3 μm.

[0079] Example 7

[0080] Prepare the adsorbent according to the method of Example 1, except that in step (3), add sulfuric acid to adjust the pH value of the slurry to 5. The prepared adsorbent is denoted as SD07 with a particle size D(4,3) of 75.9 μm.

[0081] Comparative Example 1

[0082] Dry and crush 500 g of bentonite ore until D(4,3) is 83.3 μm, add 50 g of the activated carbon powder used in Example 1, and mix well to obtain sample DSD01.

[0083] Comparative Example 2

[0084] 500 g of bentonite ore was dried and crushed to a D(4,3) of 83.3 μm, then it was dispersed in 5000 mL of hydrochloric acid solution with a hydrogen chloride concentration of 20 wt%, 50 g of the activated carbon powder used in Example 1 was added, stirred and left standing for 1 day, washed, dried and dehydrated to a water content of 7.2 wt% to obtain an acidified material; then it was calcined at 700 °C for 2 h and ground to obtain sample DSD02 with a particle size D(4,3) of 78.9 μm.

[0085] Comparative Example 3

[0086] 500 g of bentonite ore was dried and crushed to a D(4,3) of 83.3 μm, 50 g of sodium lignosulfonate and 450 g of water were added, mixed, extruded, dried and crushed to a particle size D(4,3) of 75.6 μm to obtain sample DSD03.

[0087] Comparative Example 4

[0088] The adsorbent was prepared according to the method of Example 1, except that the particle size of the slurry after delamination satisfied D(4,3) of 30.6 μm. DSD04 was obtained with a particle size D(4,3) of 82.1 μm.

[0089] Comparative Example 5

[0090] The adsorbent was prepared according to the method of Example 1, except that in step (3), sulfuric acid was not added and the pH value of the slurry was 8.6 to obtain DSD05 with a particle size D(4,3) of 80.4 μm.

[0091] Test Example 1

[0092] The adsorbent products prepared in the above examples and comparative examples were taken, and the adsorption rates for vomitoxin (DON), aflatoxin B1 (AFB1) and zearalenone (ZEN) were measured respectively according to the following methods. The results are shown in Table 1.

[0093] 1. Materials

[0094] AFB1, ZEN and DON standard products.

[0095] 2. Instrument and Equipment

[0096] Electronic balance; high-speed mixer; high-speed oscillating centrifuge; constant temperature water bath; microplate reader.

[0097] 3. Reagents

[0098] 1) Methanol;

[0099] 2) PBS buffer: NaCl: 8.0 g; KCl: 0.2 g; NaH 2 PO 4 : 1.44 g; K 2 HPO 4 : 0.24 g. Dissolve in distilled water, adjust the pH to 6.5 - 6.8, and then make up the volume to 1000 ml;

[0100] 3) 10% NaClO 4 (Dilution ratio is 1:9, V / V).

[0101] 4. Experimental procedures

[0102] (1) Preparation of mycotoxin standard solutions: First, dissolve the mycotoxin standard in methanol to make its concentration 1 mg / ml; then dilute the mycotoxin solution with PBS buffer to a certain concentration as follows:

[0103] AFB1 is diluted to 0.1 μg / ml (100 ppb), ZEN is diluted to 1 μg / ml (1000 ppb), and DON is diluted to 1 μg / ml (1000 ppb).

[0104] (2) Add 10 ml of the above - diluted mycotoxin solution to a centrifuge tube;

[0105] (3) Then add 30 mg of the adsorbent product to the above centrifuge tube to make the concentration of the adsorbent product in the solution 3.0 mg / ml;

[0106] (4) Cover the lids of the above - mentioned centrifuge tubes respectively, vortex - oscillate to disperse the samples, then place them on a constant - temperature water - bath shaker at 37 °C and 120 r / min for oscillation incubation for 90 min, centrifuge at 5000 r / min for 10 min in a centrifuge, and collect the supernatant;

[0107] (5) Set up a control group without adding the adsorbent simultaneously to eliminate the non - specific adsorption of mycotoxins during the experiment;

[0108] (6) Detect the content of the remaining mycotoxins in the supernatant by ELISA (Enzyme - Linked Immunosorbent Assay);

[0109] Calculation formula:

[0110] Q = V(C0 - C) / m

[0111] Y = 100(C0 - C) / C0

[0112] Where: Q is the adsorption capacity (ng / mg); Y is the adsorption rate (%); V is the volume of the solution (ml); m is the dosage of various adsorbents (mg); C0 and C are the concentrations of mycotoxins before and after adsorption (ng / ml).

[0113] Table 1

[0114] DON adsorption rate (%) AFB1 adsorption rate (%) ZEN adsorption rate (%) SD01 96.8 98.6 94.1 SD02 91.9 95.7 90.3 SD03 100.0 100.0 100.0 SD04 88.1 92.6 91.0 SD05 85.5 93.9 89.8 SD06 92.4 94.3 91.9 SD07 93.6 91.3 90.1 DSD01 81.5 90.1 84.4 DSD02 51.0 70.6 68.7 DSD03 36.0 96.9 45.6 DSD04 84.9 90.7 88.2 DSD05 83.8 91.1 89.0

[0115] As can be seen from the results in Table 1, the adsorbent obtained by adopting the technical solution of the present invention has good adsorption capacity for mycotoxins. Especially in Examples 1-3, the adsorption rate is higher. Compared with other adsorbents, the adsorbent provided by the present invention can significantly improve the adsorption effect on vomitoxin.

[0116] Moreover, it can be found through an electron microscope that the adsorbents prepared in Examples 1-7 have a structure of montmorillonite-coated carbon.

[0117] Test Example 2

[0118] Take the montmorillonite-coated carbon adsorbent SD01 in Example 1 and the adsorbent DSD01 in Comparative Example 1, and respectively measure the adsorption rates for nutrients (including lysine, copper, selenium, manganese, and zinc) according to the following methods:

[0119] Prepare nutrient solutions containing various nutrients according to the concentrations in the table, add the adsorbent to the nutrient solutions, with the addition amount being 0.3 wt% of the nutrient solution. After stirring for 30 min, use high-performance liquid chromatography to measure the lysine content in the nutrient solution, and use ICP-AES method to measure the contents of trace elements (including copper, selenium, manganese, and zinc) in the nutrient solution, and calculate the adsorption rate. The results of the concentrations of various nutrients and the adsorption rates of the adsorbent are shown in Table 2.

[0120] Table 2

[0121]

[0122] It can be seen that compared with the product DSD01 of Comparative Example 1, the adsorbent SD01 prepared in Example 1 of the present invention has lower adsorption rates for nutrients (among them, the adsorption rate for manganese has little difference from that of the comparative example, and it can be considered that there is almost no obvious difference). Moreover, the adsorbent products of Examples 2-7 also showed results similar to those of the product of Example 1, and their adsorption rates for nutrients are all lower. Among them, the products of Examples 2-3 are closer to the results of the product of Example 1, that is, the products of Examples 1-3 have better effects. And through testing the products of other examples and comparative examples, it is found that for the adsorption rate of lysine, the products of the examples are at least 20% lower than those of the comparative examples (for example, the product of Example 1 is even 80% lower than that of Comparative Example 1); for the overall situation of trace elements, the products of the examples are at least 10% lower than those of the comparative examples.

[0123] Compared with the comparative example, the selective adsorption of the example products for mycotoxins and nutrients is significantly enhanced.

[0124] As can be seen from Test Example 1, the adsorbent product prepared by the invention through the process of coating montmorillonite on activated carbon not only has better adsorption capacity for various toxins such as aflatoxin, zearalenone and vomitoxin, but also reduces the adsorption rate of nutrients, and has obvious selective adsorption performance.

[0125] Test Example 3

[0126] The adsorbent SD01 prepared in Example 1 was used for animal experiments.

[0127] Twenty-four healthy weaned "Duroc×Landrace×Yorkshire" triple-cross piglets at 28±1 days of age with similar body weights (9.45±0.4 kg) were selected for the experiment. During the experimental period, the 24 weaned piglets at 28±1 days of age were randomly divided into 4 groups according to the principles of similar body weight, same parity and half male and half female, with 6 replicates in each group. During the experimental period, they were allowed to eat and drink freely, disinfected and immunized according to the conventional procedures of the pig farm. The pre-trial period was 7 days, the formal period was 21 days, and the total experimental time was 28 days. The 2×2 experimental design was adopted, and the experimental groups and diets were as follows:

[0128] (1) Negative control, fed with normal diet;

[0129] (2) Negative control + adsorbent, fed with normal diet + 0.2 wt% adsorbent relative to the weight of the diet;

[0130] (3) DON group, fed with diet containing vomitoxin wheat;

[0131] (4) DON + adsorbent group, fed with diet containing mycotoxin wheat + 0.2 wt% adsorbent relative to the weight of the diet.

[0132] Each piglet was weighed at the beginning and end of the experiment, and the feed consumption was recorded every day during the experimental period. After the experiment, the average daily gain (ADG), average daily feed intake (ADFI) and feed to gain ratio (F / G) of each piglet in each group were calculated; the health status of each group of piglets was observed twice at 10:00 and 16:00 every day during the experimental period.

[0133] Twenty-four pigs were slaughtered after the experiment, and intestinal and other tissue samples were taken by dissection.

[0134] The experiment used a corn-wheat-soybean meal-based diet, which was formulated with reference to the nutrient requirements recommended by NRC (2012) for weaned piglets. The diet formula and nutrient levels are shown in Table 3.

[0135] Table 3 Basic diet formula and nutrient levels

[0136]

[0137]

[0138] a Per kilogram of feed provides: vitamin A, 8750 IU; vitamin D3, 2500 IU; vitamin E, 25 IU; vitamin K3, 2.5 mg; vitamin B1, 2.5 mg; vitamin B2, 6.25 mg; vitamin B6, 2.5 mg; vitamin B12, 25 μg; D-biotin, 100 μg; folic acid 1.25 mg; niacinamide, 25 mg; d-pantothenic acid, 12.5 mg; zinc, 80 mg; iron 100 mg; copper, 20 mg; manganese 20 mg; iodine, 0.14 mg; selenium 0.3 mg; xylanase, 200 FXU.

[0139] The content of deoxynivalenol in wheat raw materials and feed was detected by "GB / T 30956-2014 Determination of deoxynivalenol in feed - Immunoaffinity column purification - High performance liquid chromatography". The contents of zearalenone (ZEN), aflatoxin (AFB1), and T-2 toxin were detected by "NY / T 2071 Determination of aflatoxin, zearalenone and T-2 toxin in feed - Liquid chromatography - Tandem mass spectrometry".

[0140] The mycotoxin content in moldy wheat and the feed hygiene standard of GB13078-2017 are shown in Table 4.

[0141] Table 4 Mycotoxin content in moldy wheat (μg / kg)

[0142] Toxin name Moldy wheat Feed hygiene standard Vomitoxin 8260.14 ≤5000 Aflatoxin B1 2.78 ≤30 Zearalenone 375.56 ≤1000 T-2 toxin 212.64 ≤500

[0143] The mycotoxin content in feed and the feed hygiene standard of GB13078-2017 are shown in Table 5.

[0144] Table 5 Mycotoxin content in feed (μg / kg)

[0145] Toxin name Negative control diet DON group Feed hygiene standard Vomitoxin 150.16 2650.25 ≤1000 Aflatoxin B1 1.71 2.73 ≤10 Zearalenone 30.25 141.84 ≤150 T-2 toxin 50.18 118.76 ≤500

[0146] (1) Growth performance

[0147] The effects of adsorbent SD01 on the growth performance of piglets are shown in Table 6.

[0148] As can be seen from the results in Table 6, compared with the negative control group, the final weight of piglets in the DON group decreased significantly by 6.4% (P<0.05) at the end of the experiment, the average daily gain decreased significantly by 11.7% (P<0.05), and the average daily feed intake decreased significantly by 13.4% (P<0.05). There was an interaction between the adsorbent and DON treatment in the average daily feed intake of piglets (P<0.05). There was no significant difference between the DON group + adsorbent and the negative control in all data (P>0.05). Compared with the DON group without adsorbent, the average daily feed intake increased significantly (P<0.05). There was no significant difference in the feed-to-weight ratio of piglets among the four groups of experiments (P>0.05).

[0149] Table 6

[0150]

[0151] a , b,c Different letters in the same row indicate significant differences (P<0.05), and no letters or the same superscript letters in the same row indicate no significant differences (P>0.05) (the same in the following table). P is the corresponding result of the significance test.

[0152] (2) Detection of DON content in serum, muscle, liver, kidney and feces

[0153] The effects of adsorbent SD01 on the DON content in serum, muscle, liver, kidney and feces of piglets are shown in Table 7.

[0154] As can be seen from the results in Table 7, after piglets ate the feed contaminated with DON in wheat, DON residues could be detected in serum, longissimus dorsi muscle, liver, kidney and feces. After using adsorbent SD01, the DON content in serum, liver and kidney decreased significantly (P<0.05), and no detectable DON dose appeared in the longissimus dorsi muscle. The normal diet group contained DON within the specified limit, so a certain level of DON content could also be detected in feces. Adsorbent SD01 caused a significant increase in the DON content in piglet feces (P<0.05), proving that the adsorbent had good effects and could be excreted by piglets. There was an interaction between the adsorbent and DON treatment in the DON residue in piglet feces (P<0.05).

[0155] Table 7

[0156]

[0157] ND indicates not detected. The lowest detection limit of DON is 0.02 ng / g sample.

[0158] (3) Organ index

[0159] The effects of adsorbent SD01 on the organ indices of piglets are shown in Table 8. As can be seen from the results in Table 8, compared with the negative control group, the organ indices of the liver and kidneys in the DON group of piglets were significantly increased (P < 0.05), indicating that DON caused swelling of the liver and kidneys. The results of the DON + adsorbent group showed that adding adsorbent SD01 to the feed containing DON-contaminated wheat could significantly reduce the kidney organ index (P < 0.05). There were no significant differences in the results of the DON + adsorbent group compared with the negative control group (P > 0.05).

[0160] Table 8 Effects of adsorbent SD01 on the organ indices of piglets

[0161]

[0162]

[0163] (4) Jejunal villus height and crypt depth

[0164] The effects of adsorbent SD01 on the jejunal morphology of piglets are shown in Table 9.

[0165] As can be seen from the results in Table 9, DON significantly decreased the jejunal villus height (P < 0.05), significantly decreasing the jejunal villus height / crypt depth (P < 0.05). Adding adsorbent SD01 to the diet could significantly improve the effects of DON (P < 0.05). There was an interaction between the adsorbent and DON treatments on the jejunal villus height and villus height / crypt depth in piglets (P < 0.05).

[0166] Table 9

[0167]

[0168] (5) Jejunal TER and FD4 conditions

[0169] The effects of adsorbent SD01 on the jejunal barrier function of piglets are shown in Table 10.

[0170] As can be seen from the results in Table 10, compared with normal feeding, the TER (trans-epithelial electrical resistance) of the jejunum in the DON group of piglets was significantly decreased (P < 0.05), while the permeability of FD4 (fluorescein isothiocyanate-dextran) was significantly increased (P < 0.05). The results of the DON + adsorbent group showed that adsorbent SD01 could significantly improve the damage to the intestinal barrier function caused by DON (P < 0.05). There was an interaction between the adsorbent and DON treatments on the FD4 concentration in the jejunum of piglets (P < 0.05).

[0171] Table 10

[0172]

[0173] (6) Oxidative stress in jejunal mucosa

[0174] The effects of adsorbent SD01 on the antioxidant enzyme activities and MDA (malondialdehyde) content in the jejunum of piglets are shown in Table 11.

[0175] As can be seen from the results in Table 11, the SOD (superoxide dismutase) and T-AOC (total antioxidant capacity) in the jejunal mucosa of piglets decreased significantly due to DON in the feed (P < 0.05), while the MDA level increased significantly (P < 0.05). Adding adsorbent SD01 could significantly weaken the effect of DON on jejunal MDA (P < 0.05). There was no significant difference in the activity of GSH-Px (glutathione peroxidase) in the test results (P > 0.05), and there was an interaction between the adsorbent and DON treatment in the MDA content of the jejunum of piglets (P < 0.05).

[0176] Table 11

[0177]

[0178] It can also be seen from the above animal experiments that using the adsorbent provided by the present invention is beneficial to the growth performance of animals, indicating that the adsorbent provided by the present invention can reduce the impact on nutrients.

[0179] The animal experiments of the products in Examples 2-7 were similar to the results of the product in Example 1, indicating that the adsorbent prepared by the solution of the present invention is indeed beneficial to the growth performance of animals and reduces the impact on nutrients. Among them, the effects of Examples 2-3 are closer to those of Example 1, and the effects of Examples 1-3 are better. Compared with the products of the examples, the products of the comparative examples have no obvious selectivity and are difficult to overcome the problem of adsorbing nutrients.

[0180] It can be seen from the above test examples that through in vitro mycotoxin adsorption experiments and in vivo animal breeding tests, it is fully shown that the montmorillonite-coated carbon mycotoxin adsorbent provided by the present invention has strong mycotoxin adsorption ability and obvious selectivity. Under the condition of reducing the adsorption of nutrients, it can effectively alleviate the impact of vomitoxin on the growth performance of animals and improve the breeding efficiency.

[0181] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of technical features. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A preparation method of an adsorbent for removing mycotoxins, characterized in that, the method comprises: (1) providing a slurry containing montmorillonite and sodium lignosulfonate, wherein the particle size of the slurry satisfies D(4,3) ≤ 5 μm; (2) mixing the slurry of step (1) with activated carbon, and controlling the mixed material to be acidic, and obtaining a solid-phase material through post-treatment; (3) calcining the solid-phase material of step (2); wherein, in step (2), the pH of the mixed material is controlled to be ≤ 5; wherein, the temperature of the calcination is 400 - 450 °C.

2. The method according to claim 1, characterized in that, the dispersion solvent in the slurry is water.

3. The method according to claim 2, characterized in that, relative to each gram of montmorillonite, the dosage of the dispersion solvent is 6 - 18 g.

4. The method according to claim 1, characterized in that, relative to 100 g of montmorillonite, the dosage of sodium lignosulfonate is 2 - 25 g.

5. The method according to claim 4, characterized in that, relative to 100 g of montmorillonite, the dosage of sodium lignosulfonate is 5 - 22 g.

6. The method according to claim 1 or 2, characterized in that, the weight-average molecular weight of the sodium lignosulfonate is 3000 - 10000 g / mol; and / or, the montmorillonite is provided in the form of bentonite.

7. The method according to claim 1, characterized in that, the slurry is obtained by: ball-milling montmorillonite and sodium lignosulfonate to make a slurry, and exfoliating the slurry so that the particle size of the slurry after exfoliation satisfies D(4,3) ≤ 5 μm.

8. The method according to claim 7, characterized in that, the particle size of the slurry after exfoliation satisfies D(4,3) ≤ 2 μm.

9. The method according to claim 1 or 3, characterized in that, relative to 100 g of montmorillonite, the dosage of activated carbon is 1 - 25 g.

10. The method according to claim 9, characterized in that, relative to 100 g of montmorillonite, the dosage of activated carbon is 5 - 22 g.

11. The method according to claim 1, characterized in that, The specific surface area of the activated carbon is 800 - 1500 m 2 / g.

12. The method according to claim 11, characterized in that, The specific surface area of the activated carbon is 900 - 1200 m 2 / g.

13. The method according to claim 1, characterized in that, the particle size of the activated carbon satisfies: D90 ≤ 45 μm.

14. The method according to claim 1 or 2, characterized in that, in step (2), the pH of the mixed material is controlled to be 3 - 4.

15. The method according to claim 1 or 2, characterized in that, the post-treatment method includes: washing, dehydrating and drying the mixed material in sequence; and / or, the time of the calcination is 0.5 - 2 h.

16. The method according to claim 15, characterized in that, the washing makes the conductivity of the washed material ≤ 1800 S / m; and / or, the dehydration and drying make the water content in the material ≤ 10 wt%.

17. An adsorbent prepared by the method according to any one of claims 1 - 16.

18. The adsorbent according to claim 17, characterized in that, The particle size of the adsorbent satisfies that D(4,3) is 75 - 200 μm.

19. Use of the adsorbent according to claim 17 in removing mycotoxins.

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