Oligomer microsphere particles, methods of making and using the same

Abstract

This invention relates to the field of nanomaterials, and discloses an oligomeric microsphere particle, its preparation method, and its application. The oligomeric microsphere particle comprises a core portion, an intermediate layer portion, and a shell portion. The core portion contains nanoparticles, the intermediate layer portion contains silica, and the shell portion contains oligomers of Formula I and Formula II; wherein R and R' are each independently selected from -OCH2CH3 or -OCH3, x is 1-3, k is an integer from 1-5, m is an integer from 4-12, R1 is H or a C6-C15 alkyl group, y is 1-3, and q is an integer from 4-12. The oligomeric microsphere particle comprises nanoparticles, silica, a hydrophilic oligomer, and a lipophilic oligomer. The hydrophilic oligomer exhibits excellent thickening and emulsifying properties, while the lipophilic oligomer can enrich oil droplets. When placed in an oil-water environment, it can effectively separate water and oil droplets from oily wastewater.

Description

Technical Field

[0001] This invention relates to the field of nanomaterials, specifically to an oligomeric microsphere particle, its preparation method, and its application. Background Technology

[0002] Large quantities of oily wastewater exist in the oil and gas industry, fuel and chemical industry, environmental science, and resource utilization. Without effective treatment, this wastewater can have extremely adverse effects on people's lives, resource recovery, and the ecological environment. Oil in oily wastewater exists primarily in the form of floating oil, dispersed oil, emulsified oil, and micron-sized oil droplets. Different forms require different treatment methods, which can generally be categorized as chemical, biological, and physical methods. With economic growth and the development of the petroleum industry, the composition of oily wastewater is becoming increasingly complex, making separation more challenging. In recent years, numerous researchers both domestically and internationally have conducted extensive research in this area. Novel water treatment membranes and adsorption sponges have been widely applied to the separation of floating oil, dispersed oil, and even emulsified oil, achieving excellent separation results and economic benefits.

[0003] In the petroleum industry, most old oilfields have entered the mid-to-late stage of development, with the water content of produced fluids increasing year by year, leading to increasing treatment pressure and costs for produced fluid treatment stations. Currently, the overall water content of produced fluids in most oil wells exceeds 98%, resulting in tens of thousands of cubic meters of oily wastewater requiring urgent treatment and separation daily at water treatment stations. Simultaneously, the widespread use of production enhancement measures such as chemical flooding and steam flooding during oilfield development has led to more complex compositions and properties of produced fluids, characterized by high viscosity, strong emulsification stability of oil droplets and suspended solids in water, further increasing the difficulty of oil-water separation. The treatment of oil-in-water (O / W) micro-droplets is particularly challenging. Currently, research on conventional demulsifiers and demulsification technologies is focused on specific types of oily wastewater, severely limiting their application scope. Furthermore, the required demulsification temperatures are high, resulting in significant energy consumption. While it is impossible for any single demulsification technology or agent to be particularly effective for all oily wastewater, expanding the applicability of demulsification technologies or agents as much as possible will be the direction of future research efforts. Therefore, it is crucial to develop a new type of high-efficiency and universally applicable low-temperature water treatment material, especially for the separation of oil droplets in water, to provide technical support for environmental protection, energy conservation and emission reduction, and increased crude oil reserves and production. Summary of the Invention

[0004] The purpose of this invention is to overcome the problems of difficulty in separating oil droplets in water and the limited performance of core-shell particles in existing technologies. This invention provides oligomeric microspheres, their preparation method, and applications. The oligomeric microspheres contain nanoparticles, silica, hydrophilic oligomers, and lipophilic oligomers. The hydrophilic oligomers have excellent thickening and emulsifying properties, while the lipophilic oligomers can enrich oil droplets. When placed in an oil-water environment, they can effectively separate water and oil droplets in oily wastewater.

[0005] To achieve the above objectives, a first aspect of the present invention provides an oligomer microsphere particle, wherein the oligomer microsphere particle includes a core portion, an intermediate layer portion and a shell portion, the core portion comprises nanoparticles, the intermediate layer portion comprises silicon dioxide, and the shell portion comprises an oligomer of Formula I and an oligomer of Formula II.

[0006]

[0007] Where R and R' are each independently selected from -OCH2CH3 or -OCH3, x is an integer from 1 to 3, k is an integer from 1 to 5, and m is an integer from 4 to 12.

[0008] R1 is H or a C6-C15 alkyl group, y is 1-3, and q is an integer from 4 to 12.

[0009] A second aspect of the present invention provides a method for preparing oligomer microspheres, wherein the method comprises:

[0010] (1) Silicon dioxide was synthesized in situ on the surface of nanoparticles at a first temperature and under a first stirring to obtain particle I;

[0011] (2) Heat to the second temperature, add particle I to the mixed solution of paraffin and water, and form an oil-in-water emulsion under the second stirring.

[0012] (3) In the emulsion of step (2), a first silane coupling agent is added to carry out a first grafting reaction on particle I; in the presence of a water-soluble initiator and a water-soluble promoter, 2-acrylamido-2-methylpropanesulfonic acid is added to carry out a first polymerization reaction to obtain particle II;

[0013] (4) Remove the paraffin on the surface of particle II, add a second silane coupling agent, and carry out a second grafting reaction; in the presence of an oil-soluble initiator and an oil-soluble promoter, add an oil-soluble monomer, carry out a second polymerization reaction, and separate to obtain the oligomer microsphere particles.

[0014] Wherein, the first silane coupling agent is selected from acrylamide-based silane coupling agents;

[0015] The second silane coupling agent is selected from vinyl silane coupling agents.

[0016] A third aspect of the present invention provides oligomer microspheres prepared by the aforementioned preparation method.

[0017] A fourth aspect of the present invention provides the application of the aforementioned oligomeric microspheres in the oil-water separation of oily wastewater.

[0018] Through the above technical solution, the present invention has the following beneficial effects:

[0019] (1) The present invention modifies the magnetic particles with amphiphilic properties, so that the prepared oligomer microspheres contain both hydrophilic and lipophilic oligomers, which have excellent emulsification properties and can achieve the separation of fine oil droplets, thus enriching the performance of core-shell particles.

[0020] The shell contains hydrophilic oligomers, which have excellent thickening and emulsifying properties. In an oil-water environment, they can further reduce the surface tension of water and disrupt the interfacial balance of emulsified fine oil droplets. The shell also contains lipophilic oligomers, which have excellent oil droplet enrichment capabilities. In an oil-water environment, they can enrich oil droplets and facilitate the separation of water and oil droplets.

[0021] The intermediate layer contains silica, which can effectively prevent the corrosion of nanoparticles by complex oil and water environments, thus achieving effective protection for the nanoparticles.

[0022] (2) The preparation method of the present invention coats the nanoparticles with silica, which improves the stability of the nanoparticles after coating with silica, so that the obtained oligomer microspheres can be used in complex oil and water environments; and through emulsion interface control, paraffin is partially coated on the surface of the particle I, hydrophilic modification and first polymerization reaction are carried out on the uncoated part, and then the coated paraffin is removed, and lipophilic modification and second polymerization reaction are carried out on the exposed surface to obtain oligomer microspheres with rich properties.

[0023] Furthermore, by synthesizing the shell portion of the oligomers shown in Formula I and Formula II with specific structures, the size of the oligomer microspheres can be accurately controlled. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of an oil-in-water emulsion formed after the particles I of the present invention are partially coated. Detailed Implementation

[0025] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise 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 the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0026] A first aspect of the present invention provides an oligomer microsphere particle, wherein the oligomer microsphere particle includes a core portion, an intermediate layer portion and a shell portion, the core portion comprises nanoparticles, the intermediate layer portion comprises silicon dioxide, and the shell portion comprises an oligomer of Formula I and an oligomer of Formula II.

[0027]

[0028] Where R and R' are each independently selected from -OCH2CH3 or -OCH3, x is an integer from 1 to 3, k is an integer from 1 to 5, and m is an integer from 4 to 12.

[0029] R1 is H or a C6-C15 alkyl group, y is 1-3, and q is an integer from 4 to 12.

[0030] In this invention, * represents the connection site where the oligomers on the intermediate layer connect with those on the shell portion.

[0031] In this invention, m and q represent the degree of polymerization of the oligomers shown in Formula I and Formula II, respectively. The methods for testing the degree of polymerization are as follows: the degree of polymerization m is calculated by the ratio of the peak area of ​​the methyl hydrogen atom in 2-acrylamido-2-methylpropanesulfonic acid to the peak area of ​​the methylene group in the coupling agent in the 1H NMR spectrum; and the degree of polymerization q is calculated by the ratio of the peak area of ​​the hydrogen atom on the benzene ring to the peak area of ​​the methylene group in the coupling agent in the 1H NMR spectrum.

[0032] In this invention, coating the nanoparticles with silica can improve the stability of the nanoparticles, enabling the coated nanoparticles to adapt to complex oil and water environments.

[0033] Furthermore, the shell portion includes the oligomer shown in Formula I, which has excellent thickening and emulsifying properties. When placed in an oil-water environment, it can further reduce the surface tension of water and disrupt the interfacial balance of emulsified fine oil droplets. The shell portion includes the oligomer shown in Formula II, which has oleophilic properties and can quickly capture and enrich oil droplets, exhibiting excellent oil-water separation performance.

[0034] Furthermore, R and R' are each independently -OCH2CH3, k is an integer from 1 to 3, and m is an integer from 4 to 8.

[0035] Furthermore, R1 is H, a C8 alkyl group, or a C12 alkyl group, and q is an integer from 4 to 8.

[0036] In this invention, based on the total mass of the oligomeric microspheres, the content of the nanoparticles is 32-57 wt%, the content of the intermediate layer is 22-34 wt%, the content of the oligomer shown in Formula I is 2.5-15 wt%, and the content of the oligomer shown in Formula II is 14-27 wt%.

[0037] In this invention, the solutions after the in-situ synthesis reaction, the first grafting reaction, the first polymerization reaction, the second grafting reaction, and the second polymerization reaction are washed and purified to obtain the mass of the remaining unreacted substances. The mass of the remaining unreacted substances is subtracted from the total mass of the feed. Based on the change in mass before and after, the masses of the intermediate layer, the oligomer shown in Formula I, and the oligomer shown in Formula II are obtained, respectively. These masses are then divided by the total mass of the oligomer microspheres to obtain their respective contents. The nanoparticle content is obtained by dividing the mass of the nanoparticles by the total mass of the oligomer microspheres.

[0038] In this invention, the content of oligomers shown in Formula I and Formula II that satisfy the above-mentioned range results in the oligomer microspheres having better hydrophilic and lipophilic properties, thereby improving the oil-water separation effect.

[0039] Furthermore, based on the total mass of the oligomeric microspheres, the content of the nanoparticles is 40-53 wt%, the content of the intermediate layer is 25-34 wt%, the content of the oligomer shown in Formula I is 5-11 wt%, and the content of the oligomer shown in Formula II is 14-22 wt%.

[0040] According to the present invention, the particle size of the oligomer microspheres is 300-800 nm.

[0041] In this invention, the size of oligomer microspheres that meet the above-mentioned range is beneficial to disrupting the oil-water interface balance and promoting oil-water separation.

[0042] Furthermore, the particle size of the oligomer microspheres is 400-600 nm.

[0043] According to the present invention, the particle size of the nanoparticles is 100-400 nm.

[0044] In this invention, the particle size of the oligomer microspheres and the nanoparticles was tested using a BeNano 180Pro nanoparticle size analyzer.

[0045] In this invention, nanoparticles that meet the above-mentioned size range enable oligomeric microspheres to have a suitable size and exist stably at the oil-water interface.

[0046] Furthermore, the particle size of the nanoparticles is 200-300 nm.

[0047] According to the present invention, the nanoparticles are selected from at least one of elemental metals, metal alloys, and metal oxides.

[0048] In this invention, the nanoparticles are magnetic particles, which can be separated by an external magnetic field during preparation and application in oil-water separation, thereby improving preparation and application efficiency.

[0049] Furthermore, the nanoparticles are iron(III) oxide.

[0050] A second aspect of the present invention provides a method for preparing oligomer microspheres, wherein the method comprises:

[0051] (1) Silicon dioxide was synthesized in situ on the surface of nanoparticles at a first temperature and under a first stirring to obtain particle I;

[0052] (2) Heat to the second temperature, add particle I to the mixed solution of paraffin and water, and form an oil-in-water emulsion under the second stirring.

[0053] (3) In the product of step (2), a first silane coupling agent is added to carry out a first grafting reaction on particle I; in the presence of a water-soluble initiator and a water-soluble promoter, 2-acrylamido-2-methylpropanesulfonic acid is added to carry out a first polymerization reaction to obtain particle II;

[0054] (4) Remove the paraffin on the surface of particle II, add a second silane coupling agent, and carry out a second grafting reaction; in the presence of an oil-soluble initiator and an oil-soluble promoter, add an oil-soluble monomer, carry out a second polymerization reaction, and separate to obtain the oligomer microsphere particles.

[0055] Wherein, the first silane coupling agent is selected from acrylamide-based silane coupling agents;

[0056] The second silane coupling agent is selected from vinyl silane coupling agents.

[0057] In this invention, coating nanoparticles with silica improves their stability, making them suitable for complex oil-water environments.

[0058] Furthermore, by first heating to a second temperature, particle I is brought into contact with a mixture of paraffin and water to form an oil-in-water emulsion. The emulsion interface is then used to partially coat the surface of particle I with paraffin. Specifically, as shown... Figure 1 As shown, in the oil-in-water emulsion, part of particle I is embedded in the oil phase paraffin, forming a structure in which the surface of particle I is partially coated with paraffin. The uncoated part undergoes a first grafting reaction and a first polymerization reaction. Then, the coated paraffin is removed, and a second grafting reaction and a second polymerization reaction are carried out on the exposed intermediate layer surface to finally obtain amphiphilic modified oligomer microspheres.

[0059] In this invention, the in-situ synthesis of silicon dioxide is a conventional method for in-situ synthesis of silicon dioxide in the art. The following is a particularly preferred method for in-situ synthesis of silicon dioxide: adding a silicon source to an alcohol solvent.

[0060] According to the present invention, the alcohol solvent is selected from at least one of methanol, ethanol, n-butanol, isobutanol and propylene glycol, preferably ethanol.

[0061] According to the present invention, the nanoparticles are selected from at least one of elemental metals, metal alloys and metal oxides, preferably iron(III) oxide.

[0062] In this invention, the nanoparticles are magnetic particles. When preparing and applying them to oil-water separation, they can rely on an external magnetic field to separate particles I, particles II, and oligomeric microspheres containing nanoparticles from oil and water, thereby improving preparation efficiency and application efficiency.

[0063] In this invention, the magnetic field is a common magnetic field. In a preferred embodiment, a magnetic field generated by a neodymium iron boron magnet of grade N35 is used, with a magnetic induction intensity of 1170-1210 mT.

[0064] According to the present invention, the weight ratio of the nanoparticles to the silicon source is 1:0.4-0.9.

[0065] In this invention, the nanoparticles and silicon source with a weight ratio that meets the above range can ensure that silicon dioxide is uniformly coated on the surface of the nanoparticles, effectively protecting the nanoparticles, preventing the weakening of the nanoparticles' magnetism, and also providing sufficient reaction sites for the next grafting reaction.

[0066] Furthermore, the weight ratio of the nanoparticles to the silicon source is 1:0.5-0.8.

[0067] In this invention, the amount of alcohol solvent used is conventionally selected, sufficient to ensure that the nanoparticles are evenly dispersed therein.

[0068] According to the present invention, in step (2), the amount of particle I is 8-20 parts by weight relative to 100 parts by weight of the mixed solution of paraffin and water.

[0069] In this invention, the specific amount of paraffin and water mixture and particle I allows particle I to exist stably at the water-paraffin interface, so that the surface of particle I is uniformly coated with paraffin, forming a protective layer on the surface, and preventing the coated portion from participating in the first grafting reaction and the first polymerization reaction.

[0070] The mixture of paraffin and water is an oil-in-water mixture. In a particularly preferred embodiment, the weight ratio of paraffin to water in the mixture is 1:3-10, preferably 1:5-8.

[0071] Furthermore, the amount of particle I is 10-18 parts by weight relative to 100 parts by weight of the mixed solution of paraffin and water.

[0072] According to the present invention, the first silane coupling agent is selected from (3-acrylamidopropyl)triethoxysilane and / or (3-acrylamidopropyl)trimethoxysilane, preferably (3-acrylamidopropyl)triethoxysilane.

[0073] In this invention, when the first silane coupling agent is (3-acrylamidopropyl)triethoxysilane, the -OCH3CH2 in it undergoes a dehydration reaction with the -OH in the SiO2 on the intermediate layer to form a -Si-O- connection. Alternatively, it can exist in the form of -OCH3CH2 without hydrolysis, while the double bond provides reaction sites for the next graft polymerization step.

[0074] According to the present invention, the water-soluble initiator is selected from potassium persulfate and / or ammonium persulfate, preferably potassium persulfate.

[0075] According to the present invention, the water-soluble accelerator is selected from tetramethylethylenediamine and / or ethylenediamine, preferably tetramethylethylenediamine.

[0076] According to the present invention, the weight ratio of the particle I to the first silane coupling agent is 1:0.01-0.05.

[0077] In this invention, the amount of specific particle I and the first silane coupling agent can control the uniform distribution of the coupling agent on the particle surface, thereby enabling effective control of the number of hydrophilic groups.

[0078] Furthermore, the weight ratio of particle I to the first silane coupling agent is 1:0.02-0.035.

[0079] According to the present invention, the weight ratio of the first silane coupling agent to the 2-acrylamido-2-methylpropanesulfonic acid is 1:20-40.

[0080] In this invention, when the weight ratio within the above range is met, the resulting hydrophilic oligomer has excellent thickening and emulsifying properties, disrupts the interfacial balance of emulsified fine oil droplets, and greatly improves the oil-water separation effect.

[0081] Furthermore, the weight ratio of the first silane coupling agent to the 2-acrylamido-2-methylpropanesulfonic acid is 1:25-35.

[0082] According to the present invention, the weight ratio of the first silane coupling agent, the water-soluble initiator and the water-soluble accelerator is 1:0.4-0.8:0.2-0.5.

[0083] In this invention, when the above-mentioned weight ratio range is met, the first polymerization reaction proceeds more fully. When applied to the field of oil-water separation, it is beneficial to promote the oil-water separation process.

[0084] Furthermore, the weight ratio of the first silane coupling agent, the water-soluble initiator, and the water-soluble accelerator is 1:0.6-0.8:0.3-0.5.

[0085] According to the present invention, in step (4), the specific steps of removing the paraffin on the surface of particle II include: dispersing particle II in an oil-soluble solvent to remove the paraffin coating on particle II.

[0086] In this invention, the inventors achieved partial paraffin coating on the surface of particle I by controlling the emulsion interface, ensuring that only a portion of the surface of particle I undergoes the first grafting reaction and the first polymerization reaction. Then, the particle is placed in an oil-soluble solution to remove the paraffin coating on the surface. The unreacted portion of the intermediate layer undergoes the second grafting reaction and the second polymerization reaction, thereby achieving amphiphilic modification of the oligomeric microsphere particles. This can disrupt the interfacial balance of the emulsified fine oil droplets and greatly improve the oil-water separation effect.

[0087] According to the present invention, the oil-soluble solvent is selected from at least one of xylene and / or toluene, preferably xylene.

[0088] According to the present invention, the second silane coupling agent is selected from vinyltriethoxysilane and / or vinyltrimethoxysilane, preferably vinyltriethoxysilane.

[0089] According to the present invention, the oil-soluble initiator is selected from azobisisobutyronitrile and / or benzoyl peroxide, preferably azobisisobutyronitrile.

[0090] According to the present invention, the oil-soluble accelerator is selected from dodecyl mercaptan and / or tert-dodecyl mercaptan, preferably dodecyl mercaptan.

[0091] According to the present invention, the oil-soluble monomer is selected from at least one of styrene, octylstyrene, p-dodecylstyrene and p-aminostyrene, preferably at least one of styrene, octylstyrene and p-dodecylstyrene.

[0092] According to the present invention, the amount of particles II is 5-20 parts by weight relative to 100 parts by weight of the oil-soluble solvent.

[0093] In this invention, the dosage within the above range can ensure that particles II are fully dispersed in the oil-soluble solvent, which is beneficial for removing the paraffin coating on the surface of particles II, exposing the unreacted intermediate layer surface, and carrying out the second grafting reaction.

[0094] Furthermore, the amount of particles II is 5-15 parts by weight relative to 100 parts by weight of the oil-soluble solvent.

[0095] According to the present invention, the weight ratio of the particles II to the second silane coupling agent is 1:0.02-0.05.

[0096] In this invention, when the weight ratio meets the above range, the coupling agent can be evenly distributed on the particle surface, so that the particles have excellent oleophilicity.

[0097] Furthermore, the weight ratio of particle II to the second silane coupling agent is 1:0.025-0.045.

[0098] According to the present invention, the weight ratio of the second silane coupling agent to the oil-soluble monomer is 1:40-80.

[0099] In this invention, when the above-mentioned weight ratio range is met, the oligomer shown in Formula II has better oleophilicity and can enrich oil droplets in water.

[0100] Furthermore, the weight ratio of the second silane coupling agent to the oil-soluble monomer is 1:40-70.

[0101] According to the present invention, the weight ratio of the second silane coupling agent, the oil-soluble initiator and the oil-soluble accelerator is 1:0.4-0.9:0.2-0.5.

[0102] In this invention, when the above-mentioned weight ratio range is met, the second polymerization reaction proceeds more fully, and the resulting oligomer microspheres are applied in the field of oil-water separation, which is beneficial to promoting the oil-water separation process.

[0103] Furthermore, the weight ratio of the second silane coupling agent, the oil-soluble initiator, and the oil-soluble accelerator is 1:0.45-0.8:0.3-0.45.

[0104] In this invention, when the type or amount of the first silane coupling agent, the second silane coupling agent, or the oil-soluble monomer, as well as the amount of 2-acrylamido-2-methylpropanesulfonic acid, changes occur, the different reactivity of the first silane coupling agent, the second silane coupling agent, or the oil-soluble monomer, and the synergistic effect between the components, will change the content of the oligomer shown in Formula I or Formula II in the final polyacrylamide composite core-shell particles.

[0105] According to the present invention, the first temperature is 35-65°C, preferably 45-60°C, and the first stirring time is 1-3 hours, preferably 1.5-2.5 hours.

[0106] According to the present invention, the second temperature is 80-95°C, and the second stirring time is 35-60 min.

[0107] In this invention, the second temperature is higher than the melting point of paraffin wax, allowing the nanoparticles to be fully dispersed in the mixed solution of paraffin wax and water. The cooled temperature is lower than the melting point of paraffin wax, allowing the paraffin wax to coat the surface of particle II in solid form. Furthermore, controlling the second temperature to meet the above-mentioned range ensures the smooth progress of the subsequent first and second grafting reactions, resulting in the obtained oligomer core-shell particles containing the required amounts of oligomers as shown in Formula I and as shown in Formula II.

[0108] The melting point of paraffin wax is not unique. In a particularly preferred embodiment of the present invention, the melting point of paraffin wax is 47℃-64℃, preferably 49-52℃.

[0109] Furthermore, the second temperature is 80-90℃, and the second stirring time is 40-50 min.

[0110] According to the present invention, the first grafting reaction is carried out at a third temperature, wherein the third temperature is 80-95°C, preferably 80-90°C, and the time of the first grafting reaction is 1-5 hours, preferably 1.5-3.5 hours.

[0111] According to the present invention, the conditions for the first polymerization reaction include: a first polymerization reaction temperature of 80-95°C and a first polymerization reaction time of 1-3 hours.

[0112] In this invention, when the temperature and time of the first polymerization reaction meet the above-mentioned range, the oligomer shown in Formula I obtained has excellent thickening and emulsifying properties, which can further reduce the surface tension of water and disrupt the interfacial balance of emulsified fine oil droplets.

[0113] Furthermore, the conditions for the first polymerization reaction include: the first polymerization reaction temperature is 80-90℃, and the first polymerization reaction time is 1-2h.

[0114] According to the present invention, the removal of the paraffin coating on the surface of the particles III is carried out at a fourth temperature, which is 70-90°C, preferably 75-85°C.

[0115] According to the present invention, the conditions for the second grafting reaction include: the temperature of the second grafting reaction is 70-90°C, preferably 75-85°C, and the time of the second grafting reaction is 1-4 hours, preferably 1.5-2.5 hours.

[0116] According to the present invention, the conditions for the second polymerization reaction include: the temperature of the second polymerization reaction is 70-90°C, and the time of the second polymerization reaction is 1-3 hours.

[0117] In this invention, when the temperature and time of the second polymerization reaction meet the above-mentioned range, the oligomer obtained as shown in Formula II has excellent lipophilicity and can enrich oil droplets in oil and water.

[0118] Furthermore, the conditions for the second polymerization reaction include: a temperature of 75-85°C and a reaction time of 1.5-2.5 h.

[0119] A third aspect of the present invention provides oligomer microspheres prepared by the aforementioned preparation method.

[0120] A fourth aspect of the present invention provides the application of the aforementioned oligomeric microspheres in the oil-water separation of oily wastewater.

[0121] In this invention, the oily wastewater mainly includes water and emulsified suspended oil droplets, and the content of suspended oil droplets (i.e., oil content) in the oily wastewater is dynamically changing within a certain range. For example, the oil content in the oily wastewater is 130-150 mg / L.

[0122] The present invention will be described in detail below through embodiments.

[0123] The particle size of oligomer microspheres and nanoparticles was tested using a BeNano 180Pro nanoparticle size analyzer.

[0124] Oil content in wastewater: Tested according to the petroleum industry standard "SY / T0530-2011 Method for Determination of Oil Content in Oilfield Produced Water - Spectrophotometry";

[0125] Oil removal rate: According to the petroleum industry standard "SY / T0530-2011 Method for Determination of Oil Content in Oilfield Produced Water - Spectrophotometry", the oil content before and after separation treatment is C1 and C2, respectively. The oil removal rate (%) is calculated by the formula: (1-C2 / C1)×100%.

[0126] Nanoparticles: Fe3O4 particles, with particle sizes shown in Table 1, purchased from Ningbo Luofei Nanotechnology Co., Ltd.

[0127] Tetraethyl orthosilicate, (3-acrylamidopropyl)triethoxysilane, potassium persulfate, tetramethylethylenediamine, 2-acrylamido-2-methylpropanesulfonic acid, vinyltriethoxysilane, azobisisobutyronitrile, dodecyl mercaptan, styrene, octylstyrene, p-dodecylstyrene; ethanol, paraffin (grade 52#, melting point 49-52℃), and xylene are all commercially available products.

[0128] Example 1

[0129] S1. Add 16g of Fe3O4 particles to 100g of ethanol solution, heat to 65℃, add 6.4g of tetraethyl orthosilicate and stir for the first time for 1h. After separation and drying, obtain particles I-1, wherein the weight ratio of Fe3O4 particles to silicon source is 1:0.4.

[0130] S2. Weigh 15g of the above-mentioned particles I-1 and add them to 150g of a paraffin / water mixed solution at 95°C. The ratio of paraffin to water is 1:5. Stir for 35 minutes to form a stable water-in-paraffin emulsion. The content of particles I-1 is 10 parts by weight relative to 100 parts by weight of the mixed solution.

[0131] S3. In the emulsion of step S2, 0.15 g of (3-acrylamidopropyl)triethoxysilane is added to carry out the first grafting reaction for 2 hours at a temperature of 95°C. Then, 0.06 g of potassium persulfate and 0.0525 g of ethyl thiourea are added, followed by the dropwise addition of 6 g of an aqueous solution of 2-acrylamido-2-methylpropanesulfonic acid (of which 3 g is 2-acrylamido-2-methylpropanesulfonic acid) to carry out the first polymerization reaction. The temperature was 95℃, the polymerization reaction time was 3h, the magnetic particles were separated by an external magnetic field, dried under natural conditions, washed with a large amount of water and then vacuum dried to obtain particles II-1; wherein, the weight ratio of particles I-1 to the first silane coupling agent was 1:0.01, the weight ratio of the first silane coupling agent to 2-acrylamido-2-methylpropanesulfonic acid was 1:20, and the weight ratio of the first silane coupling agent, water-soluble initiator and water-soluble accelerator was 1:0.4:0.35.

[0132] S4. Weigh 10g of the above-mentioned particles II-1 and add them to 100g of xylene. Disperse them evenly. At 90℃, add 0.2g of vinyltriethoxysilane to carry out the second grafting reaction for 1h. Add 0.1g of azobisisobutyronitrile and 0.06g of dodecyl mercaptan, and then add 32g of xylene solution of p-dodecylstyrene (of which the mass of p-dodecylstyrene is 16g) to carry out the second polymerization reaction at 90℃ for 1h. Use an external magnetic field to separate the particles, wash them with a large amount of xylene, and vacuum dry the particles at 50℃ to obtain oligomer microspheres A1. The weight ratio of particles II-1 to the second silane coupling agent is 1:0.02, the weight ratio of the second silane coupling agent to the oil-soluble monomer is 1:80, and the weight ratio of the second silane coupling agent, oil-soluble initiator and oil-soluble accelerator is 1:0.5:0.3.

[0133] Based on the total mass of oligomeric microspheres A1, the content of the nanoparticles is 56.19 wt%, the content of the intermediate layer is 22.50 wt%, the content of the oligomer shown in Formula I (m is 8) is 2.76 wt%, and the content of the oligomer shown in Formula II (q is 4) is 18.55 wt%.

[0134] Example 2

[0135] S1. Add 22g of Fe3O4 particles to 200g of ethanol solution, heat to 50℃, add 11g of tetraethyl orthosilicate and stir for the first time for 2.5h. After separation and drying, obtain particles I-2; wherein, the weight ratio of Fe3O4 particles to silicon source is 1:0.5.

[0136] S2. Weigh 30g of the above-mentioned particles I-2 and add them to 200g of a paraffin / water mixed solution at 83°C. The ratio of paraffin to water is 1:5. Stir for 40 minutes to form a stable water-in-paraffin emulsion. The amount of particles I-2 used is 15 parts by weight relative to 100 parts by weight of the mixed solution.

[0137] S3. To the product of step S2, add 0.66 g of (3-acrylamidopropyl)triethoxysilane for a first grafting reaction. The first grafting reaction time is 3.5 h, and the first grafting reaction temperature is 83 °C. Add 0.429 g of potassium persulfate and 0.33 g of ethyl thiourea, and then add 33 g of an aqueous solution of 2-acrylamido-2-methylpropanesulfonic acid (of which the mass of 2-acrylamido-2-methylpropanesulfonic acid is 16.5 g) dropwise for a first polymerization reaction. The reaction temperature was 83℃, the polymerization reaction time was 1h, the magnetic particles were separated by an external magnetic field, dried under natural conditions, washed with a large amount of water and then vacuum dried to obtain particles II-2; wherein, the weight ratio of particles I-2 to the first silane coupling agent was 1:0.022, the weight ratio of the first silane coupling agent to 2-acrylamido-2-methylpropanesulfonic acid was 1:25, and the weight ratio of the first silane coupling agent, water-soluble initiator and water-soluble accelerator was 1:0.65:0.5.

[0138] S4. Weigh 20g of the above-mentioned particles II-2 and add them to 400g of xylene. Disperse them evenly. At 80℃, add 0.5g of vinyltriethoxysilane to carry out the second grafting reaction for 1.5h. Add 0.2g of azobisisobutyronitrile and 0.1g of dodecyl mercaptan, and then add 62g of xylene solution of octylstyrene (of which the mass of octylstyrene is 32.5g) to carry out the second polymerization reaction at 80℃ for 1.5h. Use an external magnetic field to separate the particles, wash them with a large amount of xylene, and vacuum dry the particles at 50℃ to obtain oligomer microspheres A2. The weight ratio of particles II-2 to the second silane coupling agent is 1:0.025, the weight ratio of the second silane coupling agent to the oil-soluble monomer is 1:65, and the weight ratio of the second silane coupling agent, oil-soluble initiator and oil-soluble accelerator is 1:0.4:0.2.

[0139] Based on the total mass of oligomeric microspheres A2, the content of the nanoparticles is 52.74 wt%, the content of the intermediate layer is 26.36 wt%, the content of the oligomer shown in Formula I (m is 8) is 5.45 wt%, and the content of the oligomer shown in Formula II (q is 4) is 15.45 wt%.

[0140] Example 3

[0141] S1. Add 30g of Fe3O4 particles to 200g of ethanol solution, heat to 45℃, add 21g of tetraethyl orthosilicate and stir for the first time for 2h. After separation and drying, obtain particles I-3; wherein, the weight ratio of Fe3O4 particles to silicon source is 1:0.7.

[0142] S2. Weigh 45g of the above-mentioned particles I-3 and add them to 200g of a paraffin / water mixed solution at 87°C. The ratio of paraffin to water is 1:5. Stir for 50 minutes to form a stable water-in-paraffin emulsion. The amount of particles I-3 used is 22.5 parts by weight relative to 100 parts by weight of the mixed solution.

[0143] S3. To the product of step S2, add 1.26 g of (3-acrylamidopropyl)triethoxysilane for a first grafting reaction. The first grafting reaction time is 2 h, and the first grafting reaction temperature is 87 °C. Add 0.756 g of potassium persulfate and 0.378 g of ethyl thiourea, and then add 88.2 g of an aqueous solution of 2-acrylamido-2-methylpropanesulfonic acid (of which the mass of 2-acrylamido-2-methylpropanesulfonic acid is 44.1 g) dropwise for a first polymerization reaction. The reaction temperature was 87℃, the polymerization reaction time was 1.5h, the magnetic particles were separated by an external magnetic field, air-dried under natural conditions, washed with a large amount of water and then vacuum-dried to obtain particles II-3; wherein, the weight ratio of particles I-3 to the first silane coupling agent was 1:0.028, the weight ratio of the first silane coupling agent to 2-acrylamido-2-methylpropanesulfonic acid was 1:35, and the weight ratio of the first silane coupling agent, water-soluble initiator and water-soluble accelerator was 1:0.6:0.3.

[0144] S4. Weigh 24g of the above-mentioned particles II-3 and add them to 200g of xylene, disperse them evenly, and add 0.84g of vinyltriethoxysilane at 85℃ to carry out the second grafting reaction for 2.5h. Then add 0.588g of azobisisobutyronitrile and 0.336g of dodecyl mercaptan, and then add 117.6g of xylene solution of p-dodecylstyrene (of which the mass of p-dodecylstyrene is 58.8g) dropwise to carry out the second polymerization reaction. The polymerization reaction temperature was 85℃, the polymerization reaction time was 2h, the particles were separated by an external magnetic field, washed with a large amount of xylene, and the particles were vacuum dried at 50℃ to obtain oligomer microspheres A3; wherein, the weight ratio of particle II-3 to the second silane coupling agent was 1:0.035, the weight ratio of the second silane coupling agent to the oil-soluble monomer was 1:70, and the weight ratio of the second silane coupling agent, the oil-soluble initiator and the oil-soluble accelerator was 1:0.7:0.4.

[0145] Based on the total mass of oligomeric microspheres A3, the content of the nanoparticles is 42.35 wt%, the content of the intermediate layer is 29.64 wt%, the content of the oligomer shown in Formula I (m is 7) is 6.95 wt%, and the content of the oligomer shown in Formula II (q is 4) is 21.06 wt%.

[0146] Example 4

[0147] S1. Add 34g of Fe3O4 particles to 200g of ethanol solution, heat to 60℃, add 27.2g of tetraethyl orthosilicate and stir for the first time for 1.5h. After separation and drying, obtain particles I-4; wherein, the weight ratio of Fe3O4 particles to silicon source is 1:0.8.

[0148] S2. Weigh 50g of the above-mentioned particles I-4 and add them to 200g of a paraffin / water mixed solution at 90°C. The ratio of paraffin to water is 1:5. Stir for 45 minutes to form a stable water-in-paraffin emulsion. The amount of particles I-4 used is 25 parts by weight relative to 100 parts by weight of the mixed solution.

[0149] S3. To the product of step S2, add 1.75 g of (3-acrylamidopropyl)triethoxysilane for a first grafting reaction. The first grafting reaction time is 3 h, and the first grafting reaction temperature is 90 °C. Add 1.4 g of potassium persulfate and 0.7 g of ethyl thiourea, and then add 122.5 g of an aqueous solution of 2-acrylamido-2-methylpropanesulfonic acid (of which the mass of 2-acrylamido-2-methylpropanesulfonic acid is 61.25 g) dropwise for a first polymerization reaction. The reaction temperature was 90℃, the polymerization reaction time was 2h, the magnetic particles were separated by an external magnetic field, dried under natural conditions, washed with a large amount of water and then vacuum dried to obtain particles II-4; wherein, the weight ratio of particles I-4 to the first silane coupling agent was 1:0.035, the weight ratio of the first silane coupling agent to 2-acrylamido-2-methylpropanesulfonic acid was 1:35, and the weight ratio of the first silane coupling agent, water-soluble initiator and water-soluble accelerator was 1:0.8:0.4.

[0150] S4. Weigh 30g of the above-mentioned particles II-4 and add them to 200g of xylene, disperse them evenly, and add 1.29g of vinyltriethoxysilane at 75℃ to carry out the second grafting reaction for 2 hours. Then add 1.032g of azobisisobutyronitrile and 0.645g of dodecyl mercaptan, and then add 103.2g of xylene solution of p-styrene (of which the mass of styrene is 51.6g) dropwise to carry out the second polymerization reaction. The polymerization reaction temperature is... The polymerization reaction was carried out at 75℃ for 2.5 hours. The particles were separated using an external magnetic field, washed with a large amount of xylene, and then vacuum dried at 50℃ to obtain oligomer microspheres A4. The weight ratio of particles II-4 to the second silane coupling agent was 1:0.043, the weight ratio of the second silane coupling agent to the oil-soluble monomer was 1:40, and the weight ratio of the second silane coupling agent, the oil-soluble initiator, and the oil-soluble accelerator was 1:0.8:0.5.

[0151] Based on the total mass of oligomeric microspheres A4, the content of the nanoparticles is 42.05 wt%, the content of the intermediate layer is 33.65 wt%, the content of the oligomer shown in Formula I (m is 8) is 10.23 wt%, and the content of the oligomer shown in Formula II (q is 5) is 14.07 wt%.

[0152] Example 5

[0153] S1. Add 40g of Fe3O4 particles to 200g of ethanol solution, heat to 35℃, add 36g of tetraethyl orthosilicate and stir for the first time for 3h. After separation and drying, obtain particles I-5; wherein, the weight ratio of Fe3O4 particles to silicon source is 1:0.9.

[0154] S2. Weigh 60g of the above-mentioned particles I-5 and add them to 200g of a paraffin / water mixed solution at 80°C. The ratio of paraffin to water is 1:5. Stir for 60 minutes to form a stable water-in-paraffin emulsion. The amount of particles I-5 used is 30 parts by weight relative to 100 parts by weight of the mixed solution.

[0155] S3. In the product of step S2, 3g of (3-acrylamidopropyl)triethoxysilane is added to carry out the first grafting reaction for 4 hours at a temperature of 80°C. 2.1g of potassium persulfate and 0.6g of ethyl thiourea are added, followed by the addition of 240g of an aqueous solution of 2-acrylamido-2-methylpropanesulfonic acid (120g of which is 2-acrylamido-2-methylpropanesulfonic acid) to carry out the first polymerization reaction at a temperature of 80°C for 1 hour. The magnetic particles are separated using an external magnetic field, air-dried under natural conditions, washed with a large amount of water, and then vacuum-dried to obtain particles II-5. The weight ratio of particles II-5 to the first silane coupling agent is 1:0.05, the weight ratio of the first silane coupling agent to 2-acrylamido-2-methylpropanesulfonic acid is 1:40, and the weight ratio of the first silane coupling agent, water-soluble initiator, and water-soluble accelerator is 1:0.7:0.2.

[0156] S4. Weigh 24g of the above-mentioned particles II-5 and add them to 300g of xylene. Disperse them evenly. At 70°C, add 1.2g of vinyltriethoxysilane to carry out the second grafting reaction for 4 hours. Add 0.96g of azobisisobutyronitrile and 0.42g of dodecyl mercaptan, and then add 120g of styrene xylene solution (of which the mass of styrene is 60g) to carry out the second polymerization reaction at 70°C for 3 hours. Use an external magnetic field to separate the particles, wash them with a large amount of xylene, and vacuum dry the particles at 50°C to obtain oligomer microspheres A5. The weight ratio of particles II-5 to the second silane coupling agent is 1:0.05, the weight ratio of the second silane coupling agent to the oil-soluble monomer is 1:50, and the weight ratio of the second silane coupling agent, oil-soluble initiator and oil-soluble accelerator is 1:0.8:0.35.

[0157] Based on the total mass of oligomeric microspheres A5, the content of the nanoparticles is 32.38 wt%, the content of the intermediate layer is 29.14 wt%, the content of the oligomer shown in Formula I (m is 10) is 14.70 wt%, and the content of the oligomer shown in Formula II (q is 10) is 23.78 wt%.

[0158] Example 6

[0159] The process was carried out according to Example 3, except that in step S3, 2.025 g of (3-acrylamidopropyl)triethoxysilane was added to prepare oligomer microspheres A6. The weight ratio of particles I-3 to the first silane coupling agent was 1:0.045, the weight ratio of the first silane coupling agent to 2-acrylamido-2-methylpropanesulfonic acid was 1:21.8, and the weight ratio of the first silane coupling agent, the water-soluble initiator, and the water-soluble accelerator was 1:0.39:0.19.

[0160] Based on the total mass of oligomeric microspheres A6, the content of the nanoparticles is 39.67 wt%, the content of the intermediate layer is 27.76 wt%, the content of the oligomer shown in Formula I (m is 8) is 11.93 wt%, and the content of the oligomer shown in Formula II (q is 4) is 20.64 wt%.

[0161] Example 7

[0162] The process was carried out according to Example 3, except that in step S3, 4.05 g of (3-acrylamidopropyl)triethoxysilane was added to prepare oligomeric microspheres A7. The weight ratio of particles I-3 to the first silane coupling agent was 1:0.09, the weight ratio of the first silane coupling agent to 2-acrylamido-2-methylpropanesulfonic acid was 1:10.9, and the weight ratio of the first silane coupling agent, the water-soluble initiator, and the water-soluble accelerator was 1:0.19:0.09.

[0163] Based on the total mass of oligomeric microspheres A7, the content of the nanoparticles is 34.81 wt%, the content of the intermediate layer is 24.36 wt%, the content of the oligomer shown in Formula I (m is 8) is 20.94 wt%, and the content of the oligomer shown in Formula II (q is 4) is 19.89 wt%.

[0164] Example 8

[0165] The process was carried out in accordance with Example 3, except that in step S4, 1.128 g of vinyltriethoxysilane was added to obtain oligomer microspheres A8. The weight ratio of particles II-3 to the second silane coupling agent was 1:0.047, the weight ratio of the second silane coupling agent to the oil-soluble monomer was 1:52, and the weight ratio of the second silane coupling agent, the oil-soluble initiator, and the oil-soluble accelerator was 1:0.52:0.3.

[0166] Based on the total mass of oligomeric microspheres A8, the content of the nanoparticles is 39.50 wt%, the content of the intermediate layer is 27.64 wt%, the content of the oligomer shown in Formula I (m is 7) is 6.48 wt%, and the content of the oligomer shown in Formula II (q is 3) is 26.38 wt%.

[0167] Example 9

[0168] The process was carried out according to Example 3, except that in step S4, 0.24 g of vinyltriethoxysilane was added to obtain oligomer microspheres A9. The weight ratio of particles II-3 to the second silane coupling agent was 1:0.01, the weight ratio of the second silane coupling agent to the oil-soluble monomer was 1:245, and the weight ratio of the second silane coupling agent, the oil-soluble initiator, and the oil-soluble accelerator was 1:2.45:1.4.

[0169] Based on the total mass of oligomeric microspheres A9, the content of the nanoparticles is 49.95 wt%, the content of the intermediate layer is 34.96 wt%, the content of the oligomer shown in Formula I (m is 7) is 8.19 wt%, and the content of the oligomer shown in Formula II (q is 4) is 6.90 wt%.

[0170] Example 10

[0171] The process was carried out in accordance with Example 3, except that in step S3, 50.4 g of 2-acrylamido-2-methylpropanesulfonic acid was added to obtain oligomer microspheres A10. The weight ratio of the first silane coupling agent to 2-acrylamido-2-methylpropanesulfonic acid was 1:40.

[0172] Based on the total mass of the oligomeric microspheres A10, the content of the nanoparticles is 41.93 wt%, the content of the intermediate layer is 29.36 wt%, the content of the oligomer shown in Formula I (m is 11) is 7.71 wt%, and the content of the oligomer shown in Formula II (q is 4) is 21 wt%.

[0173] Example 11

[0174] The process was carried out according to Example 3, except that in step S3, 12.6 g of 2-acrylamido-2-methylpropanesulfonic acid was added to obtain oligomer microspheres A11. The weight ratio of the first silane coupling agent to 2-acrylamido-2-methylpropanesulfonic acid was 1:100.

[0175] Based on the total mass of oligomeric microspheres A11, the content of the nanoparticles is 44.98 wt%, the content of the intermediate layer is 31.49 wt%, the content of the oligomer shown in Formula I (m is 2) is 2.06 wt%, and the content of the oligomer shown in Formula II (q is 4) is 21.47 wt%.

[0176] Example 12

[0177] The process was carried out in accordance with Example 3, except that in step S4, 134.4 g of xylene solution of p-dodecylstyrene (of which the mass of p-dodecylstyrene was 67.2 g) was added to prepare oligomer microspheres A12, wherein the weight ratio of the second silane coupling agent to the oil-soluble monomer was 1:80.

[0178] Based on the total mass of oligomeric microspheres A12, the content of the nanoparticles is 40.53 wt%, the content of the intermediate layer is 28.37 wt%, the content of the oligomer shown in Formula I (m is 7) is 6.65 wt%, and the content of the oligomer shown in Formula II (q is 5) is 24.45 wt%.

[0179] Example 13

[0180] The process was carried out in accordance with Example 3, except that in step S4, 33.6 g of xylene solution of p-dodecylstyrene (of which the mass of p-dodecylstyrene was 16.8 g) was added to prepare oligomer microspheres A13, wherein the weight ratio of the second silane coupling agent to the oil-soluble monomer was 1:20.

[0181] Based on the total mass of oligomeric microspheres A13, the content of the nanoparticles is 46.53 wt%, the content of the intermediate layer is 32.56 wt%, the content of the oligomer shown in Formula I (m is 7) is 7.63 wt%, and the content of the oligomer shown in Formula II (q is 2) is 13.28 wt%.

[0182] Example 14

[0183] The procedure was carried out as described in Example 3, except that in step S2, the second temperature was 95°C. Oligomeric microspheres A14 were obtained.

[0184] Based on the total mass of oligomeric microspheres A14, the content of the nanoparticles is 44.25 wt%, the content of the intermediate layer is 26.38 wt%, the content of the oligomer shown in Formula I (m is 4) is 4.43 wt%, and the content of the oligomer shown in Formula II (q is 4) is 24.94 wt%.

[0185] Example 15

[0186] The process was carried out in accordance with Example 3, except that in step S2, the second temperature was 65°C. Oligomeric microspheres A15 were obtained.

[0187] Based on the total mass of the oligomer microspheres, the content of the nanoparticles is 48.51 wt%, the content of the intermediate layer is 20.44 wt%, the content of the oligomer shown in Formula I (m is 9) is 7.48 wt%, and the content of the oligomer shown in Formula II (q is 4) is 23.57 wt%.

[0188] Comparative Example 1

[0189] The procedure was carried out as described in Example 3, except that step S3 was omitted. Oligomeric microspheres D1 were obtained.

[0190] Based on the total mass of the oligomer microspheres, the content of the nanoparticles is 38.53 wt%, the content of the intermediate layer is 26.97 wt%, the content of the oligomer shown in Formula I is 0 wt%, and the content of the oligomer shown in Formula II (q is 5) is 34.50 wt%.

[0191] Comparative Example 2

[0192] The procedure was carried out as described in Example 3, except that in step S3, an equal mass of acrylic acid was used to replace 2-acrylamido-2-methylpropanesulfonic acid. Oligomeric microspheres D2 were obtained.

[0193] Based on the total mass of the oligomer microspheres, the content of the nanoparticles is 44.32 wt%, the content of the intermediate layer is 31.03 wt%, the content of the oligomer shown in Formula I (m is 10) is 3.29 wt%, and the content of the oligomer shown in Formula II (q is 4) is 21.36 wt%.

[0194] Comparative Example 3

[0195] The process was carried out as described in Example 3, except that step S4 was omitted, and the surface of the particles was partially covered with paraffin. Oligomeric microspheres D3 were obtained.

[0196] Based on the total mass of the oligomer microspheres, the content of the nanoparticles is 34.08 wt%, the content of the intermediate layer is 23.86 wt%, the content of the oligomer (m = 7) shown in Formula I is 5.59 wt%, and the content of the oligomer shown in Formula II is 0 wt%.

[0197] In Comparative Example 3, since step S4 was not performed, the surface of the obtained oligomer microspheres was still partially coated with paraffin. Based on the total mass of the oligomer microspheres, the content of paraffin coating was 36.47 wt%.

[0198] Comparative Example 4

[0199] The process was carried out in accordance with Example 3, except that in step S4, an equal mass of methyl methacrylate was used instead of p-dodecylstyrene to prepare oligomer microspheres D4.

[0200] Based on the total mass of the oligomer microspheres, the content of the nanoparticles is 46.05 wt%, the content of the intermediate layer is 32.23 wt%, the content of the oligomer shown in Formula I (m is 7) is 7.56 wt%, and the content of the oligomer shown in Formula II (q is 5) is 14.16 wt%.

[0201] Comparative Example 5

[0202] The procedure was carried out as described in Example 3, except that in step S3, an equal mass of Si-69 was used instead of (3-acrylamidopropyl)triethoxysilane. Oligomeric microspheres D5 were obtained.

[0203] Based on the total mass of the oligomeric microspheres, the content of the nanoparticles is 44.72 wt%, the content of the intermediate layer is 31.30 wt%, the content of Si-69 is 1.32 wt%, and the content of the compound shown in Formula II is 22.66 wt%.

[0204] In Comparative Example 5, Si-69 does not contain polymeric double bonds and cannot be further grafted with acrylamide. Therefore, the core-shell particles D3 do not contain the oligomer structure shown in Formula I, but only the structure of Si-69.

[0205] Table 1

[0206]

[0207] * - refers to the content of Si-69 grafted onto the core-shell particles.

[0208] The sizes of the prepared oligomer microspheres are shown in Table 1.

[0209] Table 1

[0210]

[0211]

[0212] Test case

[0213] 1 g of the oligomeric microspheres prepared in the examples and comparative examples were weighed and added to 100 mL of oily wastewater. After ultrasonic vibration for 5 min, the mixture was placed in a magnetic field (magnetic field strength 1170-1210 mT). Under the action of the magnetic field, the oligomeric microspheres adsorbing oil droplets underwent directional transport. After stabilization, the mixture was filtered. Then, referring to SY / T0530-2011 Method for Determination of Oil Content in Oilfield Produced Water - Spectrophotometry, the oil content before and after separation treatment was measured as C1 and C2, respectively. The oil removal rate (%) was calculated using the formula: (1-C2 / C1)×100%.

[0214] The effects of oligomeric microspheres on wastewater treatment are shown in Table 2.

[0215] Table 2

[0216]

[0217] As can be seen from the results in Tables 1 and 2, compared with the comparative example, the oligomer microspheres prepared in the embodiments of the present invention can significantly improve the oil removal rate when used to treat oily wastewater.

[0218] 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 inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. An oligomeric microsphere particle, characterized in that, The oligomer microspheres include a core portion, an intermediate layer portion, and a shell portion. The core portion contains nanoparticles, the intermediate layer portion contains silicon dioxide, and the shell portion contains oligomers shown in Formula I and oligomers shown in Formula II. Formula I, Formula II, Where R and R' are each independently selected from -OCH2CH3 or -OCH3, x is an integer from 1 to 3, k is an integer from 1 to 5, and m is an integer from 4 to 12. R1 is H or a C6-C15 alkyl group, y is 1-3, and q is an integer from 4 to 12.

2. The oligomeric microsphere particle of claim 1, wherein, R and R' are each independently -OCH2CH3, k is an integer from 1 to 3, and m is an integer from 4 to 8.

3. The oligomeric microsphere particle of claim 1, wherein, R1 is H, a C8 alkyl group, or a C12 alkyl group, and q is an integer from 4 to 8.

4. The oligomeric microparticle of any one of claims 1-3, wherein, Based on the total mass of the oligomeric microspheres, the content of the nanoparticles is 32-57 wt%, the content of the intermediate layer is 22-34 wt%, the content of the oligomer shown in Formula I is 2.5-15 wt%, and the content of the oligomer shown in Formula II is 14-27 wt%.

5. The oligomeric microparticle of any one of claims 1-3, wherein, Based on the total mass of the oligomeric microspheres, the content of the nanoparticles is 40-53 wt%, the content of the intermediate layer is 25-34 wt%, the content of the oligomer shown in Formula I is 5-11 wt%, and the content of the oligomer shown in Formula II is 14-22 wt%.

6. The oligomeric microparticle of any one of claims 1-3, wherein, The oligomer microspheres have a particle size of 300-800 nm.

7. The oligomeric microparticle of any one of claims 1-3, wherein, The oligomer microspheres have a particle size of 400-600 nm.

8. The oligomeric microparticle of any one of claims 1-3, wherein, The nanoparticles have a particle size of 100-400 nm.

9. The oligomeric microparticle of any one of claims 1-3, wherein, The nanoparticles have a particle size of 200-300 nm.

10. The oligomeric microparticle of any one of claims 1-3, wherein, The nanoparticles are selected from at least one of elemental metals, metal alloys, and metal oxides.

11. The oligomeric microparticle of any one of claims 1-3, wherein, The nanoparticles are iron(III) oxide.

12. A method for producing the oligomeric microparticle according to any one of claims 1 to 11, characterized in that The method includes: (1) Silicon dioxide was synthesized in situ on the surface of nanoparticles at the first temperature and under the first stirring to obtain particle I; (2) Heat to the second temperature, add particle I to the mixed solution of paraffin and water, and form an oil-in-water emulsion under the second stirring. (3) In the emulsion of step (2), a first silane coupling agent is added to carry out a first grafting reaction on particle I; in the presence of a water-soluble initiator and a water-soluble promoter, 2-acrylamido-2-methylpropanesulfonic acid is added to carry out a first polymerization reaction to obtain particle II; (4) Remove the paraffin on the surface of particle II, add a second silane coupling agent, and carry out a second grafting reaction; in the presence of an oil-soluble initiator and an oil-soluble promoter, add an oil-soluble monomer, carry out a second polymerization reaction, and separate to obtain the oligomer microsphere particles. Wherein, the first silane coupling agent is selected from acrylamide-based silane coupling agents; The second silane coupling agent is selected from vinyl silane coupling agents.

13. The method of making according to claim 12, wherein, Step (1) includes: the in-situ synthesis of silicon dioxide includes: mixing nanoparticles with a silicon source in the presence of an alcohol solvent.

14. The production method according to claim 13, wherein The alcohol solvent is selected from at least one of methanol, ethanol, n-butanol, isobutanol, and propylene glycol.

15. The production method according to claim 13, wherein The silicon source is selected from tetraethyl orthosilicate and / or tetrabutyl orthosilicate.

16. The production method according to claim 12 or 13, wherein The nanoparticles are selected from at least one of elemental metals, metal alloys, and metal oxides.

17. The method of making according to claim 12 or 13, wherein, The nanoparticles are iron(III) oxide.

18. The method of making according to any one of claims 12-15, wherein, The weight ratio of the nanoparticles to the silicon source is 1:0.4-0.

9.

19. The method of making according to any one of claims 12-15, wherein, The weight ratio of the nanoparticles to the silicon source is 1:0.5-0.

8.

20. The preparation method according to claim 12, wherein, In step (2), the amount of particle I is 8-20 parts by weight relative to 100 parts by weight of the mixed solution of paraffin and water.

21. The method of manufacturing according to claim 12, wherein, In step (2), the amount of particle I is 10-18 parts by weight relative to 100 parts by weight of the mixed solution of paraffin and water.

22. The method of manufacturing according to claim 12, wherein, In step (3), the first silane coupling agent is selected from (3-acrylamidopropyl)triethoxysilane and / or (3-acrylamidoethyl)triethoxysilane.

23. The method of manufacturing according to claim 12, wherein, In step (3), the first silane coupling agent is (3-acrylamidopropyl)triethoxysilane.

24. The method of manufacturing according to claim 12, wherein, In step (3), the water-soluble initiator is selected from potassium persulfate and / or ammonium persulfate.

25. The method of manufacturing according to claim 12, wherein, In step (3), the water-soluble accelerator is selected from tetramethylethylenediamine and / or ethylenediamine.

26. The method of manufacturing according to claim 12, wherein, In step (3), the weight ratio of particle I to the first silane coupling agent is 1:0.01-0.

05.

27. The method of manufacturing according to claim 12, wherein, In step (3), the weight ratio of particle I to the first silane coupling agent is 1:0.02-0.

035.

28. The method of manufacturing according to claim 12, wherein, In step (3), the weight ratio of the first silane coupling agent to the 2-acrylamido-2-methylpropanesulfonic acid is 1:20-40.

29. The method of manufacturing according to claim 12, wherein, In step (3), the weight ratio of the first silane coupling agent to the 2-acrylamido-2-methylpropanesulfonic acid is 1:25-35.

30. The method of manufacturing according to claim 12, wherein, In step (3), the weight ratio of the first silane coupling agent, the water-soluble initiator and the water-soluble promoter is 1:0.4-0.8:0.2-0.

5.

31. The method of manufacturing according to claim 12, wherein, In step (3), the weight ratio of the first silane coupling agent, the water-soluble initiator and the water-soluble promoter is 1:0.6-0.8:0.3-0.

5.

32. The method of manufacturing according to claim 12, wherein, In step (4), the specific steps for removing the paraffin wax from the surface of particle II include: dispersing particle II in an oil-soluble solvent to remove the paraffin wax coating on particle II.

33. The method of manufacturing according to claim 32, wherein, The oil-soluble solvent is selected from at least one of xylene and / or toluene.

34. The method of manufacturing according to claim 12, wherein, In step (4), the second silane coupling agent is selected from vinyltriethoxysilane and / or vinyltrimethoxysilane.

35. The method of manufacturing according to claim 12, wherein, In step (4), the oil-soluble initiator is selected from azobisisobutyronitrile and / or benzoyl peroxide.

36. The method of manufacturing according to claim 12, wherein, In step (4), the oil-soluble accelerator is selected from dodecyl mercaptan and / or tert-dodecyl mercaptan.

37. The method of manufacturing according to claim 12, wherein, In step (4), the oil-soluble monomer is selected from at least one of styrene, octylstyrene, p-dodecylstyrene and p-aminostyrene.

38. The method of manufacturing according to claim 12, wherein, In step (4), the oil-soluble monomer is at least one of styrene, octylstyrene and p-dodecylstyrene.

39. The method of making according to any one of claims 32-38, wherein, In step (4), the amount of particle II is 5-20 parts by weight relative to 100 parts by weight of the oil-soluble solvent.

40. The method of making according to any one of claims 32-38, wherein, In step (4), the amount of particle II is 5-15 parts by weight relative to 100 parts by weight of the oil-soluble solvent.

41. The preparation method according to claim 12, wherein, In step (4), the weight ratio of particle II to the second silane coupling agent is 1:0.02-0.

05.

42. The method of manufacturing according to claim 12, wherein, In step (4), the weight ratio of particle II to the second silane coupling agent is 1:0.025-0.

045.

43. The method of manufacturing according to claim 12, wherein, In step (4), the weight ratio of the second silane coupling agent to the oil-soluble monomer is 1:40-80.

44. The method of manufacturing according to claim 12, wherein, In step (4), the weight ratio of the second silane coupling agent to the oil-soluble monomer is 1:40-70.

45. The method of manufacturing according to claim 12, wherein, In step (4), the weight ratio of the second silane coupling agent, the oil-soluble initiator and the oil-soluble accelerator is 1:0.4-0.9:0.2-0.

5.

46. The method of manufacturing according to claim 12, wherein, In step (4), the weight ratio of the second silane coupling agent, the oil-soluble initiator and the oil-soluble accelerator is 1:0.45-0.8:0.3-0.

45.

47. The method of manufacturing according to claim 12, wherein, The first temperature is 35-65℃, and the first stirring time is 1-3h.

48. The method of manufacturing according to claim 12, wherein, The first temperature is 45-60℃, and the first stirring time is 1.5-2.5h.

49. The method of manufacturing according to claim 12, wherein, The second temperature is 80-95℃, and the second stirring time is 35-60 min.

50. The method of manufacturing according to claim 12, wherein, The second temperature is 80-90℃, and the second stirring time is 40-50 min.

51. The preparation method according to claim 12, wherein, The first grafting reaction was carried out at a third temperature.

52. The method of manufacturing according to claim 51, wherein, The third temperature is 80-95℃.

53. The method of manufacturing according to claim 51, wherein, The third temperature is 80-90℃.

54. The preparation method according to claim 12, wherein, In step (3), the first grafting reaction takes 1-5 hours.

55. The method of manufacturing according to claim 12, wherein, In step (3), the first grafting reaction takes 1.5-3.5 hours.

56. The method of manufacturing according to claim 12, wherein, In step (3), the conditions for the first polymerization reaction include: the first polymerization reaction temperature is 80-95℃ and the first polymerization reaction time is 1-3h.

57. The method of manufacturing according to claim 12, wherein, In step (3), the conditions for the first polymerization reaction include: the first polymerization reaction temperature is 80-90℃ and the first polymerization reaction time is 1-2h.

58. The method of manufacturing of claim 12, wherein, The removal of the paraffin coating on particle II was carried out at a fourth temperature.

59. The method of manufacturing according to claim 58, wherein, The fourth temperature is 70-90℃.

60. The preparation method according to claim 58, wherein, The fourth temperature is 75-85℃.

61. The method of manufacturing of claim 12, wherein, In step (4), the conditions for the second grafting reaction include: the temperature of the second grafting reaction is 70-90℃, and the time of the second grafting reaction is 1-4h.

62. The method of manufacturing according to claim 12, wherein, In step (4), the conditions for the second grafting reaction include: the temperature of the second grafting reaction is 75-85℃, and the time of the second grafting reaction is 1.5-2.5h.

63. The method of manufacturing of claim 12, wherein, In step (4), the conditions for the second polymerization reaction include: the temperature of the second polymerization reaction is 70-90℃ and the time of the second polymerization reaction is 1-3h.

64. The preparation method according to claim 12, wherein, In step (4), the conditions for the second polymerization reaction include: the temperature of the second polymerization reaction is 75-85℃, and the time of the second polymerization reaction is 1.5-2.5h.

65. Oligomeric microspheres prepared by the preparation method according to any one of claims 12-64.

66. The application of the oligomer microspheres according to any one of claims 1-11 or 65 in the oil-water separation of oily wastewater.

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