Composite material and method for adsorbing phthalic acid ester in vegetable oil

Abstract

The invention relates to a composite material and a method for adsorbing phthalic acid ester in vegetable oil. The invention relates to a composite material for adsorbing phthalic acid ester in vegetable oil. The composite material comprises a porous cryogel skeleton and a metal oxide dispersed in the porous cryogel skeleton. According to the composite material and the method for adsorbing the phthalic acid ester in the vegetable oil, the methyl methacrylate and the metal oxide are adopted to prepare the efficient adsorbent aiming at the edible oil plasticizer pollution problem, and the adsorption process is optimized; the adsorbent is simple in preparation process and easy to recycle and reuse, an excellent plasticizer removal effect can be achieved under mild conditions, and an economical and effective solution is provided for edible oil safety.

Description

Technical Field

[0001] The present invention belongs to the technical field of edible oil treatment, and particularly relates to a composite material and method for adsorbing phthalic acid esters in vegetable oil. Background Art

[0002] As a commonly used plasticizer, phthalic acid esters (PAEs) are widely used in industrial fields such as plastics and coatings. However, studies have shown that these compounds have reproductive toxicity and neurotoxicity, and may cause health problems such as endocrine disorders and decreased immunity. With the increasingly strict restrictions on the use of phthalic acid esters in various countries, their pollution problems in food have also attracted widespread attention.

[0003] Due to the strong lipophilicity of PAEs, they are easily enriched in high-fat foods such as edible oil, and then enter the human body through diet. Relevant research shows that the detection rate of phthalic acid esters in commercially available edible oil in some regions is as high as over 50%, and the pollution problems of short-chain phthalic acid esters such as dibutyl phthalate (DBP) are particularly prominent.

[0004] Currently, the main technical bottlenecks faced in the adsorption and removal of phthalic acid esters in oils and fats include: the adsorption agent method mostly uses traditional adsorbents such as activated carbon. These adsorbents have low mass transfer efficiency in oils and fats and lack the selective adsorption ability for phthalic acid esters. In addition, traditional adsorbents often need to be combined with harsh conditions such as high temperature and vacuum, which not only consumes a lot of energy but also may cause oxidation and deterioration of oils and fats.

[0005] In view of this, the present invention proposes a new composite material and method for adsorbing phthalic acid esters in vegetable oil, and creatively embeds metal oxides in a hydrogel matrix to develop a new composite material with both high mass transfer and high adsorption efficiency. Summary of the Invention

[0006] Aiming at the problems of low adsorption efficiency, harsh operating conditions, poor selectivity, etc. existing in the existing technologies for removing phthalic acid ester plasticizers in vegetable oil, the present invention provides a composite material and method for adsorbing phthalic acid esters in vegetable oil.

[0007] The object of the present invention is to provide a composite material for adsorbing phthalic acid esters in vegetable oil, which is a highly efficient, mild and reusable metal oxide hydrogel composite adsorbent.

[0008] In order to achieve the above object, the technical solution adopted is as follows:

[0009] A composite material for adsorbing phthalic acid esters in vegetable oil, comprising: a porous hydrogel skeleton and metal oxides dispersed in the porous hydrogel skeleton.

[0010] Further, the metal oxide is selected from at least one of zinc oxide, copper oxide, and aluminum oxide.

[0011] Further, the mass ratio of the metal oxide to the porous crystalline gel framework is 0.2 - 1:1.

[0012] Another object of the present invention is to provide a method for preparing a composite material for adsorbing phthalates in vegetable oil, and this preparation method is simple and easy to implement.

[0013] To achieve the above object, the technical solution adopted is:

[0014] The preparation method of the above composite material is: the metal oxide is embedded in the porous crystalline gel framework by in-situ synthesis.

[0015] Further, the specific preparation method is as follows:

[0016] (1) Mix the metal oxide and the crystalline gel prepolymer solution evenly to obtain a mixed solution;

[0017] (2) Drop the mixed solution into liquid nitrogen to achieve instantaneous freezing and shaping, obtaining frozen particles;

[0018] (3) Continuously freeze the frozen particles in paraffin oil at -8 to -12 °C for 22 to 26 h to form wet crystalline gel particles;

[0019] (4) After the wet crystalline gel particles are thawed, wash them with petroleum ether to remove paraffin oil, then soak them in a surfactant solution, wash them with water, and after freeze-drying, obtain the composite material.

[0020] Still further, in step (1), the mass ratio of the metal oxide to the crystalline gel prepolymer solution is 0.06 - 0.3:10;

[0021] In step (4), the surfactant solution is a 0.4 - 0.6 wt% sodium dodecylbenzenesulfonate solution.

[0022] Still further, the surfactant solution is a 0.5 wt% sodium dodecylbenzenesulfonate solution.

[0023] Still further, in step (3), the frozen particles are continuously frozen in paraffin oil at -10 °C for 24 h;

[0024] In step (4), after the wet crystalline gel particles are thawed at room temperature for 5 to 30 min, wash them with petroleum ether for 15 to 30 min, then soak them in the surfactant solution for 28 to 32 min, and wash them with water 5 to 10 times.

[0025] Another object of the present invention is to provide a method for adsorbing phthalic acid esters in vegetable oil. This method uses the above-mentioned composite material and has the advantages of simplicity, high efficiency, mildness, etc.

[0026] In order to achieve the above object, the technical solution adopted is as follows:

[0027] A method for adsorbing phthalic acid esters in vegetable oil is as follows: after using an adsorbent to adsorb and remove phthalic acid esters in vegetable oil, filter and centrifuge to obtain purified vegetable oil;

[0028] The adsorbent is the above-mentioned composite material or the composite material prepared by the above-mentioned preparation method.

[0029] Furthermore, the dosage of the adsorbent is 1-5 wt% of the vegetable oil;

[0030] The temperature for adsorption and removal is 25-40 °C, and the time is 12-24 h.

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0032] The composite material and method for adsorbing phthalic acid esters in vegetable oil according to the present invention innovatively combines the macroporous mass transfer advantage of the crystalline gel carrier and the adsorption characteristics of metal oxides, overcoming the long-existing technical bottleneck in the field of removing plasticizers from edible oils, namely the difficulty in synergistically optimizing "efficiency - selectivity - recyclability". Practical applications show that this technology is not only simple to operate and low in energy consumption, but also can effectively maintain the quality of oils and fats, providing a new solution for the safe production of edible oils and having important industrial promotion value. Specifically:

[0033] 1. The technical solution of the present invention prepares a crystalline gel material with a three-dimensional through macroporous structure (pore diameter 1-30 μm), providing an excellent mass transfer channel for high-viscosity vegetable oil and significantly improving the contact efficiency between plasticizer molecules and adsorption sites.

[0034] 2. The technical solution of the present invention prepares a composite material in which metal oxides are uniformly distributed on the surface of the crystalline gel framework, fully exposing the active sites. Moreover, the surface of the metal oxide (such as zinc oxide) is rich in hydroxyl groups and oxygen vacancies, and forms a strong bond with the ester group of phthalic acid ester molecules through coordination.

[0035] 3. The technical solution of the present invention prepares a composite material that exhibits excellent purification performance: high adsorption efficiency, with a PAEs removal rate ≥ 70%, significantly superior to traditional inorganic adsorbents; mild operating conditions, enabling efficient removal at low temperature and normal pressure, avoiding oil oxidation caused by high temperature; the adsorbent can be reused, and after being washed and regenerated with n-hexane, it can maintain an adsorption efficiency of more than 60% after being reused 3 times. Description of the Drawings

[0036] Figure 1 Scanning electron microscope image of the composite material (mass ratio of zinc oxide to crystal gum skeleton is 1:1) prepared in Example 1 of the present invention;

[0037] Figure 2 Scanning electron microscope image of the composite material (mass ratio of zinc oxide to crystal gum skeleton is 0.5:1) prepared in Example 2 of the present invention;

[0038] Figure 3 Scanning electron microscope image of the composite material (mass ratio of zinc oxide to crystal gum skeleton is 0.2:1) prepared in Example 3 of the present invention. Detailed implementation manners

[0039] In order to further elaborate a composite material and method for adsorbing phthalic acid esters in vegetable oil according to the present invention and achieve the expected invention purpose, the following combines preferred embodiments to detail the specific implementation manners, structures, features and their effects of a composite material and method for adsorbing phthalic acid esters in vegetable oil according to the present invention. In the following description, different "one embodiment" or "embodiment" do not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0040] The following will further introduce in detail a composite material and method for adsorbing phthalic acid esters in vegetable oil according to the present invention in combination with specific embodiments:

[0041] The present invention belongs to the edible oil safety treatment technology in the field of food science and technology, and specifically relates to a functional adsorbent material for removing phthalic acid ester plasticizers in vegetable oil and its application method. More specifically, the present invention relates to a composite adsorbent prepared by doping and modifying a crystal gum material with a metal oxide, and a process method for removing plasticizers in edible oil.

[0042] Due to its unique macroporous structure (pore diameter 10 - 100 μm), the crystal gum material can provide an ideal mass transfer channel for oils with higher viscosities. At the same time, the surface of the metal oxide is rich in hydroxyl groups and oxygen vacancies, and can form a strong bond with the ester groups in phthalic acid ester molecules through coordination. Based on these characteristics, the present invention creatively embeds the metal oxide in the crystal gum matrix to develop a new composite material with both high mass transfer and high adsorption efficiency. The technical solution of the present invention is as follows:

[0043] A composite material for adsorbing phthalic acid esters in vegetable oil, comprising: a porous crystal gum skeleton and a metal oxide dispersed in the porous crystal gum skeleton.

[0044] Preferably, the metal oxide is selected from at least one of zinc oxide, copper oxide and aluminum oxide.

[0045] In the above technical solution, the metal oxide is in the form of nanoparticles and is uniformly distributed on the surface of the crystalline colloid framework.

[0046] Preferably, the mass ratio of the metal oxide to the porous crystalline colloid framework is 0.2 - 1:1.

[0047] The preparation method of the above composite material is as follows: the metal oxide is embedded in the porous crystalline colloid framework by an in-situ synthesis method.

[0048] Preferably, the specific preparation method is as follows:

[0049] (1) Mix the metal oxide and the crystalline colloid prepolymer solution evenly to obtain a mixed solution;

[0050] (2) Drop the mixed solution into liquid nitrogen to achieve instantaneous freezing and shaping, obtaining frozen particles;

[0051] (3) Continuously freeze the frozen particles in paraffin oil at -8 to -12 °C for 22 to 26 h to form wet crystalline colloid particles;

[0052] (4) After the wet crystalline colloid particles are thawed, wash them with petroleum ether to remove the paraffin oil, then soak them in a surfactant solution, wash them with water, and after freeze-drying, obtain the composite material.

[0053] More preferably, in step (1), the mass ratio of the metal oxide to the crystalline colloid prepolymer solution is 0.06 - 0.3:10;

[0054] In step (4), the surfactant solution is a 0.4 - 0.6 wt% sodium dodecylbenzenesulfonate solution.

[0055] More preferably, the surfactant solution is a 0.5 wt% sodium dodecylbenzenesulfonate solution.

[0056] More preferably, in step (3), the frozen particles are continuously frozen in paraffin oil at -10 °C for 24 h;

[0057] In step (4), after the wet crystalline colloid particles are thawed at room temperature for 5 - 30 min, wash them with petroleum ether for 15 - 30 min, then soak them in the surfactant solution for 28 - 32 min, and wash them with water 5 - 10 times.

[0058] In the above technical solution, the purpose of soaking and cleaning the wet gel particles with petroleum ether, surfactant, and water in sequence is as follows: after thawing at room temperature, the paraffin oil is removed by washing with petroleum ether. After soaking in the surfactant solution, deionized water is repeatedly rinsed 3 - 5 times (changing water every 1 - 2 h) to remove the freezing medium paraffin oil, unreacted substances, and sulfolane.

[0059] A method for adsorbing phthalates in vegetable oil is as follows: after adsorbing and removing phthalates in vegetable oil using an adsorbent, filtration and centrifugation are carried out to obtain purified vegetable oil.

[0060] The adsorbent described above is the composite material as described above or the composite material prepared by the preparation method as described above.

[0061] Preferably, the dosage of the adsorbent is 1 - 5 wt% of the vegetable oil.

[0062] The temperature for the adsorption removal is 25 - 40 °C, and the time is 12 - 24 h.

[0063] Example 1.

[0064] The specific operation steps are as follows:

[0065] (1) Preparation of the adsorbent:

[0066] Dissolve 0.9 g of monomer (methyl methacrylate) in 30 g of liquid sulfolane solvent to prepare a mixed solution with a mass fraction of 3 wt%. Then add 0.178 g of cross - linker (ethylene glycol dimethacrylate), 0.621 g of oxidant (benzoyl peroxide), 0.621 g of reducing agent (N,N - dimethylaniline), and 0.9 g of zinc oxide (the mass ratio of the metal oxide to the porous gel skeleton is 1:1, that is, the mass ratio of the metal oxide to the prepolymer solution is 0.3:10. The prepolymer solution includes: monomer (methyl methacrylate), liquid sulfolane solvent, cross - linker (ethylene glycol dimethacrylate), oxidant (benzoyl peroxide), reducing agent (N,N - dimethylaniline)) into the mixed solution, and stir for 10 min to form a uniform raw material liquid, that is, the mixed solution.

[0067] The mixed solution is instantaneously frozen by dropping it into liquid nitrogen at a rate of 1 mL / min through an injection pump to achieve instantaneous freezing and shaping, obtaining frozen particles.

[0068] Transfer the frozen particles to paraffin oil at - 10 °C and cure for 24 h to form wet gel particles.

[0069] After thawing the wet hydrogel particles at room temperature for 30 min, wash them with petroleum ether for 30 min to remove the freezing medium paraffin oil. Then soak them in a 0.5 wt% sodium dodecyl sulfate solution for 30 min, and wash them 5 times with deionized water (changing the water every 2 h) to remove unreacted substances and sulfolane. Finally, obtain white porous particles through freeze-drying, which are the composite materials described above.

[0070] Observe the microscopic morphology of the composite hydrogel material through a scanning electron microscope (SEM). The results are as Figure 1 shown, indicating that the material has a micron-scale three-dimensional through-porous structure, and the pore size ranges from 2.5 to 27.4 μm. Zinc oxide particles are evenly dispersed on the surface of the polymer skeleton without obvious agglomeration.

[0071] (2) Removal of phthalate plasticizers in soybean oil:

[0072] Take 1.0 g of the above composite material as an adsorbent and add it to 20 g of soybean oil (the initial DBP content in soybean oil is 1.6 mg / kg, DEHP is 5.32 mg / kg, and DINP is 1.72 mg / kg). Stir and adsorb at 200 rpm in a 35 °C constant temperature water bath for 12 h.

[0073] GC-MS detection of the treated oil sample shows that the residual amounts of DBP, DEHP, and DINP are reduced to 0.18 mg / kg (removal rate 88.8%), 1.04 mg / kg (removal rate 80.4%), and 0.26 mg / kg (removal rate 84.8%) respectively.

[0074] After the adsorbent is regenerated by ultrasonic treatment with n-hexane-ethanol (1:1, v / v) for 20 min and reused 3 times, the removal rates of DBP, DEHP, and DINP still remain at 71.3%, 68.5%, and 65.2% respectively, and the particle integrity rate > 95%.

[0075] Example 2.

[0076] The specific operation steps are as follows:

[0077] (1) Preparation of the adsorbent:

[0078] Dissolve 0.9 g of monomer (methyl methacrylate) in 30 g of liquid sulfolane solvent to prepare a mixed solution with a mass fraction of 3%. Then add 0.178 g of cross-linking agent (ethylene glycol dimethacrylate), 0.621 g of oxidant (benzoyl peroxide), 0.621 g of reducing agent (N,N-dimethylaniline), and 0.18 g of zinc oxide (the mass ratio of metal oxide to porous hydrogel skeleton is 0.2:1, that is, the mass ratio of metal oxide to hydrogel prepolymer solution is 0.06:10) to the mixed solution, and stir for 10 min to form a uniform raw material liquid, that is, the mixed solution.

[0079] The mixed solution was dropped into liquid nitrogen at a rate of 1 mL / min through a syringe pump for instant freezing, achieving instant freezing and shaping to obtain frozen particles.

[0080] The frozen particles were transferred to -10°C paraffin oil and solidified for 24 h to form wet cryogel particles.

[0081] The wet crystal colloidal particles were thawed at room temperature for 30 minutes, washed with petroleum ether for 30 minutes to remove the freezing medium paraffin oil, and then soaked in 0.5wt% sodium lauryl sulfate solution for 30 minutes. They were then washed with deionized water five times (with water changed every 2 hours) to remove unreacted substances and cyclopentane. Finally, white porous particles were obtained by freeze-drying, namely the composite material.

[0082] The microstructure of the composite crystal gel material was observed by scanning electron microscopy (SEM). Figure 2 The results show that the material has a micron-scale three-dimensional porous structure with pore sizes ranging from 5.5 to 21.5 μm. The zinc oxide particles are evenly dispersed on the surface of the polymer skeleton without obvious agglomeration.

[0083] (2) Removal of phthalate plasticizers from soybean oil:

[0084] 1.0 g of the composite material was taken as an adsorbent and added to 20 g of soybean oil with an initial DBP content of 1.6 mg / kg, DEHP of 5.32 mg / kg, and DINP of 1.72 mg / kg. The mixture was stirred and adsorbed at 200 rpm in a constant temperature water bath at 35°C for 12 h.

[0085] GC-MS analysis of the treated oil samples showed that the residual levels of DBP, DEHP, and DINP were reduced to 0.29 mg / kg (removal rate 81.8%), 1.47 mg / kg (removal rate 72.3%), and 0.46 mg / kg (removal rate 73.2%), respectively.

[0086] After the adsorbent was regenerated by ultrasonic treatment with n-hexane-ethanol (1:1, v / v) for 20 min, the removal rates of DBP, DEHP and DINP remained at 70.3%, 62.3% and 63.8% respectively after repeated use for three times, and the particle integrity rate was >95%.

[0087] Example 3.

[0088] The specific steps are as follows:

[0089] (1) Preparation of adsorbent:

[0090] Dissolve 0.9 g of monomer (methyl methacrylate) in 30 g of liquid sulfolane solvent to prepare a mixed solution with a mass fraction of 3%. Then add 0.178 g of crosslinking agent (ethylene glycol dimethacrylate), 0.621 g of oxidizing agent (benzoyl peroxide), 0.621 g of reducing agent (N,N-dimethylaniline), and 0.45 g of zinc oxide (the mass ratio of metal oxide to porous crystal gum skeleton is 0.5:1, that is, the mass ratio of metal oxide to prepolymer solution is 0.14:10) to the mixed solution and stir for 10 min to form a uniform raw material liquid, namely the mixed solution.

[0091] The mixed solution is instantaneously frozen by dropping it into liquid nitrogen at a rate of 1 mL / min through an injection pump to achieve instant freezing and shaping, obtaining frozen particles.

[0092] Transfer the frozen particles to paraffin oil at -10 °C and cure for 24 h to form wet crystal gum particles.

[0093] After thawing the wet crystal gum particles at room temperature for 30 min, wash them with petroleum ether for 30 min to remove the freezing medium paraffin oil, then soak them in a 0.5 wt% sodium dodecyl sulfate solution for 30 min, and then wash them 5 times with deionized water (changing water every 2 h) to remove unreacted substances and sulfolane. Finally, obtain white porous particles through freeze-drying, namely the composite material described above.

[0094] Observe the microscopic morphology of the composite crystal gum material through a scanning electron microscope (SEM). The results are as Figure 3 shown, indicating that the material has a micron-scale three-dimensional through-hole porous structure, and the pore size range is 6.7 - 26.5 μm. Zinc oxide particles are evenly dispersed on the surface of the polymer skeleton without obvious agglomeration phenomenon. [[ID=…]]

[0095] (2) Removal of phthalate plasticizers in soybean oil:

[0096] Take 1.0 g of the above composite material as an adsorbent and add it to 20 g of soybean oil with an initial DBP content of 1.6 mg / kg, DEHP of 5.32 mg / kg, and DINP of 1.72 mg / kg, and stir and adsorb at 200 rpm in a 35 °C constant temperature water bath for 12 h.

[0097] GC-MS detection of the treated oil sample shows that the residual amounts of DBP, DEHP, and DINP are reduced to 0.24 mg / kg (removal rate 85.0%), 1.35 mg / kg (removal rate 74.6%), and 0.30 mg / kg (removal rate 82.5%) respectively.

[0098] After the adsorbent was regenerated by ultrasonic treatment with n - hexane - ethanol (1:1, v / v) for 20 min and reused three times, the removal rates of DBP, DEHP, and DINP remained at 71.3%, 64.3%, and 63.8% respectively, and the particle integrity rate was > 95%.

[0099] Example 4.

[0100] The specific operation steps are as follows:

[0101] (1) Preparation of the adsorbent:

[0102] Dissolve 0.9 g of monomer (methyl methacrylate) in 30 g of liquid sulfolane solvent to prepare a mixed solution with a mass fraction of 3%. Then add 0.178 g of cross - linker (ethylene glycol dimethacrylate), 0.621 g of oxidant (benzoyl peroxide), 0.621 g of reductant (N,N - dimethylaniline), and 0.45 g of copper oxide (the mass ratio of metal oxide to porous crystal gum skeleton is 0.5:1, that is, the mass ratio of metal oxide to crystal gum prepolymer solution is 0.14:10) to the mixed solution, and stir for 10 min to form a uniform raw material liquid, namely the mixed solution.

[0103] The mixed solution is dropped into liquid nitrogen at a rate of 1 mL / min through an injection pump for instantaneous freezing to achieve instantaneous freezing and shaping, obtaining frozen particles.

[0104] Transfer the frozen particles to paraffin oil at - 10 °C for curing for 24 h to form wet crystal gum particles.

[0105] After thawing the wet crystal gum particles at room temperature for 30 min, wash them with petroleum ether for 30 min to remove the freezing medium paraffin oil, then soak them in 0.5 wt% sodium dodecyl sulfate solution for 30 min, and then wash them with deionized water 5 times (changing water every 2 h) to remove unreacted substances and sulfolane. Finally, obtain white porous particles through freeze - drying, namely the composite material.

[0106] SEM characterization shows that the material has a micron - scale three - dimensional through - pore structure, and copper oxide particles are evenly distributed on the surface of the skeleton.

[0107] (2) Removal of phthalate plasticizers in soybean oil:

[0108] Take 1.0 g of the above - mentioned composite material as the adsorbent and add it to 20 g of soybean oil with an initial DBP content of 1.6 mg / kg, DEHP of 5.32 mg / kg, and DINP of 1.72 mg / kg. Stir and adsorb at 200 rpm in a 35 °C constant - temperature water bath for 12 h.

[0109] GC-MS detection of the treated oil sample showed that the residual amounts of DBP, DEHP, and DINP decreased to 0.27 mg / kg (removal rate 83.1%), 1.45 mg / kg (removal rate 72.7%), and 0.41 mg / kg (removal rate 76.7%), respectively.

[0110] After the adsorbent was regenerated by ultrasonic treatment with n-hexane-ethanol (1:1, v / v) for 20 min and reused three times, the removal rates of DBP, DEHP, and DINP remained at 73.2%, 65.3%, and 65.8%, respectively, and the particle integrity rate was >95%.

[0111] Example 5.

[0112] The specific operation steps are as follows:

[0113] (1) Preparation of the adsorbent:

[0114] Dissolve 0.9 g of the monomer (methyl methacrylate) in 30 g of the liquid sulfolane solvent to prepare a mixed solution with a mass fraction of 3%. Then add 0.178 g of the cross-linking agent (ethylene glycol dimethacrylate), 0.621 g of the oxidizing agent (benzoyl peroxide), 0.621 g of the reducing agent (N,N-dimethylaniline), and 0.45 g of alumina (the mass ratio of the metal oxide to the porous crystal gel skeleton is 0.5:1, that is, the mass ratio of the metal oxide to the crystal gel prepolymer solution is 0.14:10) to the mixed solution and stir for 10 min to form a uniform raw material liquid, i.e., the mixed solution.

[0115] The mixed solution was dropped into liquid nitrogen at a rate of 1 mL / min through a syringe pump for instantaneous freezing to achieve instantaneous freezing and shaping, obtaining frozen particles.

[0116] Transfer the frozen particles to paraffin oil at -10°C for curing for 24 h to form wet crystal gel particles.

[0117] After the wet crystal gel particles were thawed at room temperature for 30 min, they were washed with petroleum ether for 30 min to remove the freezing medium paraffin oil, then soaked in a 0.5 wt% sodium dodecyl sulfate solution for 30 min, and then washed with deionized water 5 times (changing the water every 2 h) to remove unreacted substances and sulfolane. Finally, white porous particles, i.e., the composite material, were obtained by freeze-drying.

[0118] SEM characterization showed that the material had a micron-scale three-dimensional through-hole structure, and alumina particles were evenly distributed on the surface of the skeleton.

[0119] (2) Removal of phthalate plasticizers in soybean oil:

[0120] Take 1.0 g of the above composite material as the adsorbent and add it to 20 g of soybean oil with an initial DBP content of 1.6 mg / kg, DEHP of 5.32 mg / kg, and DINP of 1.72 mg / kg. Stir and adsorb at 200 rpm in a 35 °C constant temperature water bath for 12 h.

[0121] GC-MS detection of the treated oil sample showed that the residual amounts of DBP, DEHP, and DINP decreased to 0.17 mg / kg (removal rate 89.7%), 1.27 mg / kg (removal rate 77.4%), and 0.28 mg / kg (removal rate 83.7%), respectively.

[0122] After the adsorbent was regenerated by ultrasonic treatment with n-hexane-ethanol (1:1, v / v) for 20 min and reused 3 times, the removal rates of DBP, DEHP, and DINP remained at 76.3%, 69.1%, and 67.2%, respectively, and the particle integrity rate was >95%.

[0123] Example 6.

[0124] The specific operation steps are as follows:

[0125] (1) Preparation of the adsorbent:

[0126] Dissolve 0.9 g of the monomer (methyl methacrylate) in 30 g of the liquid sulfolane solvent to prepare a mixed solution with a mass fraction of 3 wt%. Then add 0.178 g of the cross-linking agent (ethylene glycol dimethacrylate), 0.621 g of the oxidizing agent (benzoyl peroxide), 0.621 g of the reducing agent (N,N-dimethylaniline), and 0.9 g of zinc oxide (the mass ratio of the metal oxide to the porous crystal gel skeleton is 1:1, that is, the mass ratio of the metal oxide to the crystal gel prepolymer solution is 0.3:10) to the mixed solution and stir for 10 min to form a uniform raw material liquid, i.e., the mixed solution.

[0127] The mixed solution was dropped into liquid nitrogen at a rate of 1 mL / min by an injection pump for instantaneous freezing to achieve instantaneous freezing and shaping, obtaining frozen particles.

[0128] Transfer the frozen particles to -8 °C paraffin oil and cure for 26 h to form wet crystal gel particles.

[0129] After thawing the wet crystal gel particles at room temperature for 5 min, wash them with petroleum ether for 25 min to remove the freezing medium paraffin oil, then soak them in a 0.4 wt% sodium dodecyl sulfate solution for 32 min, and then wash them 4 times with deionized water (changing the water every 1.5 h) to remove unreacted substances and sulfolane. Finally, obtain white porous particles by freeze-drying, i.e., the composite material.

[0130] (2) Removal of phthalate plasticizers in soybean oil:

[0131] Take 1.0 g of the above composite material as the adsorbent and add it to 100 g of soybean oil (the initial DBP content of soybean oil is 1.6 mg / kg, DEHP is 5.32 mg / kg, and DINP is 1.72 mg / kg). Stir and adsorb at 200 rpm in a constant temperature water bath at 40 °C for 24 h.

[0132] GC-MS detection of the treated oil sample shows that the residual amounts of DBP, DEHP, and DINP are reduced to 0.28 mg / kg (removal rate 82.5%), 1.46 mg / kg (removal rate 72.5%), and 0.50 mg / kg (removal rate 70.8%) respectively.

[0133] Example 7.

[0134] The specific operation steps are as follows:

[0135] (1) Preparation of the adsorbent:

[0136] Dissolve 0.9 g of the monomer (methyl methacrylate) in 30 g of the liquid sulfolane solvent to prepare a mixed solution with a mass fraction of 3 wt%. Then add 0.178 g of the cross-linking agent (ethylene glycol dimethacrylate), 0.621 g of the oxidizing agent (benzoyl peroxide), 0.621 g of the reducing agent (N,N-dimethylaniline), and 0.9 g of zinc oxide (the mass ratio of the metal oxide to the porous crystal gel skeleton is 1:1, that is, the mass ratio of the metal oxide to the crystal gel prepolymer solution is 0.3:10) to the mixed solution, and stir for 10 min to form a uniform raw material liquid, that is, the mixed solution.

[0137] The mixed solution is dropped into liquid nitrogen through an injection pump at a rate of 1 mL / min for instantaneous freezing to achieve instantaneous freezing and shaping, obtaining frozen particles.

[0138] Transfer the frozen particles to paraffin oil at -12 °C and cure for 22 h to form wet crystal gel particles.

[0139] After thawing the wet crystal gel particles at room temperature for 25 min, wash them with petroleum ether for 15 min to remove paraffin oil, then soak them in a 0.6 wt% sodium dodecyl sulfate solution for 28 min, and then wash them 3 times with deionized water (changing water every 2 h) to remove the freezing medium paraffin oil, unreacted substances, and sulfolane. Finally, obtain white porous particles through freeze-drying, that is, the composite material.

[0140] (2) Removal of phthalate plasticizers in soybean oil:

[0141] Take 1.0 g of the above composite material as an adsorbent and add it to 40 g of soybean oil (the initial DBP content of soybean oil is 1.6 mg / kg, DEHP is 5.32 mg / kg, and DINP is 1.72 mg / kg). Stir and adsorb at 200 rpm in a constant temperature water bath at 25 °C for 18 h.

[0142] GC-MS detection of the treated oil sample shows that the residual amounts of DBP, DEHP, and DINP are reduced to 0.23 mg / kg (removal rate 85.6%), 1.32 mg / kg (removal rate 75.1%), and 0.36 mg / kg (removal rate 79.0%), respectively.

[0143] As mentioned above, it is only the preferred embodiment of the embodiments of the present invention, and there is no restriction in any form on the embodiments of the present invention. Any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the embodiments of the present invention still fall within the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A composite material for adsorbing phthalates in vegetable oil, characterized in that, The composite material described above includes: a porous crystalline colloid framework and metal oxides dispersed in the porous crystalline colloid framework.

2. The composite material according to claim 1, wherein the metal oxides are selected from at least one of zinc oxide, copper oxide, and aluminum oxide.

3. The composite material according to claim 1, wherein the mass ratio of the metal oxides to the porous crystalline colloid framework is 0.2 - 1:

1.

4. The method for preparing the composite material according to any one of claims 1 to 3, characterized in that The preparation method is as follows: the metal oxides are embedded in the porous crystalline colloid framework by an in-situ synthesis method.

5. The preparation method according to claim 4, wherein The specific preparation method is as follows: (1) Mix the metal oxides and the crystalline colloid prepolymer solution evenly to obtain a mixed solution; (2) Drop the mixed solution into liquid nitrogen to achieve instantaneous freezing and shaping, obtaining frozen particles; (3) Continuously freeze the frozen particles in paraffin oil at -8 to -12 °C for 22 to 26 h to form wet crystalline colloid particles; (4) After the wet crystalline colloid particles are thawed, wash them with petroleum ether to remove the paraffin oil, then soak them in a surfactant solution, wash them with water, and freeze-dry them to obtain the composite material.

6. The preparation method according to claim 5, wherein in step (1), the mass ratio of the metal oxides to the crystalline colloid prepolymer solution is 0.06 - 0.3:10; in step (4), the surfactant solution is a 0.4 - 0.6 wt% sodium dodecylbenzenesulfonate solution.

7. The preparation method according to claim 6, wherein the surfactant solution is a 0.5 wt% sodium dodecylbenzenesulfonate solution.

8. The preparation method according to claim 5, wherein in step (3), the frozen particles are continuously frozen in paraffin oil at -10 °C for 24 h; in step (4), after the wet crystalline colloid particles are thawed at room temperature for 5 - 30 min, wash them with petroleum ether for 15 - 30 min, then soak them in the surfactant solution for 28 - 32 min, and wash them with water 5 - 10 times.

9. A method for adsorbing phthalates in vegetable oil, characterized in that, The method is as follows: after adsorbing and removing phthalate esters in vegetable oil using an adsorbent, filter and centrifuge to obtain purified vegetable oil; The adsorbent is the composite material according to any one of claims 1 - 3 or the composite material prepared by the preparation method according to claims 4 - 8.

10. The method according to claim 9, wherein the dosage of the adsorbent is 1 - 5 wt% of the vegetable oil; the temperature for adsorption and removal is 25 - 40 °C, and the time is 12 - 24 h.

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