Magnetic multi-effect organic-inorganic composite amphiphilic particles, and preparation method and application thereof

Abstract

The application relates to the technical field of sewage treatment, and provides a magnetic multi-effect organic-inorganic composite amphiphilic particle as well as a preparation method and application thereof. The magnetic multi-effect organic-inorganic composite amphiphilic particle comprises a magnetic Fe3O4 particle core and a silica shell layer which are separated from each other; the outer surface of the silica shell layer comprises a hydrophilic part and a hydrophobic part; the hydrophilic part is obtained by modifying the outer surface of the silica shell layer with a silane coupling agent containing amino groups so that the amino groups are grafted on the outer surface of the silica shell layer; the inner surface of the silica shell layer and the surface of the magnetic Fe3O4 particle core are grafted with poly (dimethylaminoethyl methacrylate); and the silica shell layer has a micro-pore structure. The magnetic multi-effect organic-inorganic composite amphiphilic particle provided by the application has excellent emulsifying performance and can realize oil-water separation; meanwhile, the magnetic multi-effect organic-inorganic composite amphiphilic particle also has selective adsorption characteristics and can efficiently treat oil-containing sewage containing partially hydrolyzed polyacrylamide in one step.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sewage treatment, and more particularly to a magnetic multi-effect organic-inorganic composite amphiphilic particle and a preparation method and application thereof. BACKGROUND

[0002] Hydrolyzed polyacrylamide (HPAM) is often accompanied by high concentration in oil-containing wastewater in oilfields. HPAM accumulates and transforms in the environment, resulting in a large amount of toxic and harmful polymer-containing wastewater and polymer-containing sludge. Therefore, it is necessary to remove hydrolyzed polyacrylamide in organic wastewater. However, the treatment of oil-containing wastewater containing hydrolyzed polyacrylamide is more difficult than that of ordinary oil-containing wastewater, and the existing treatment method generally needs to use multi-step treatment to achieve the treatment of oil-containing wastewater containing hydrolyzed polyacrylamide to meet the standard. How to efficiently remove hydrolyzed polyacrylamide while realizing oil-water separation in one step has been a difficult problem in the treatment of oil-containing wastewater containing hydrolyzed polyacrylamide.

[0003] Amphiphilic solid particle emulsifiers have excellent emulsifying capacity, and can realize emulsification by reducing the interfacial tension, have high interfacial desorption energy, and realize efficient and stable emulsification of emulsions. If the amphiphilic solid particles have magnetism, the emulsified droplets have magnetism, and then the dispersed phase droplets can be manipulated. Based on this, the magnetic amphiphilic solid particles can be used to treat oil-containing wastewater, realize the emulsification of oil in water, and realize the stable dispersion of the dispersed phase oil droplets. Under the control of an external magnetic field, the oil droplets can be migrated and enriched, and then oil-water separation can be realized. However, although the existing amphiphilic solid particle emulsifiers can successfully realize oil-water separation when applied to treat oil-containing wastewater containing hydrolyzed polyacrylamide, they cannot efficiently remove hydrolyzed polyacrylamide in oil-containing wastewater in one step. Therefore, it is very meaningful to develop an amphiphilic solid particle emulsifier that can efficiently remove hydrolyzed polyacrylamide in oil-containing wastewater. SUMMARY

[0004] The present application aims to provide a magnetic multi-effect organic-inorganic composite amphiphilic particle and a preparation method thereof, to solve the technical problem in the prior art that oil-containing wastewater containing hydrolyzed polyacrylamide is difficult to be treated in one step to meet the standard.

[0005] To achieve the above-mentioned purpose, the technical solution adopted by the present application is:

[0006] In a first aspect, the present application provides a magnetic multi-effect organic-inorganic composite amphiphilic particle, which comprises a core-shell separated magnetic Fe3O4 particle core and a silica shell layer; the outer surface of the silica shell layer comprises a hydrophilic part and a hydrophobic part, the hydrophilic part is modified by a silane coupling agent containing amino groups on the outer surface of the silica shell layer to make the outer surface of the silica shell layer carry amino groups, and the amino groups are grafted with polydopamine; the inner surface of the silica shell layer and the surface of the magnetic Fe3O4 particle core are grafted with poly(diethylaminoethyl methacrylate) (PDEAEMA), and the silica shell layer has a micro-pore structure.

[0007] It should be noted that the "micro-pore structure" in the present application includes intermolecular gaps in the silica macromolecular skeleton and defects generated in the core-shell separation process of the silica shell layer from the magnetic Fe3O4 particle core, and even micropores and capillary pores with a pore size of 0.5-50 nm.

[0008] The magnetic multi-effect organic-inorganic composite amphiphilic particle provided by the present application has a silica shell layer coated outside the magnetic Fe3O4 particle core, which can protect the internal magnetic Fe3O4 particle core, resist corrosion of hydrochloric acid, sulfuric acid, nitric acid and the like on the internal magnetic Fe3O4 particle core for a certain period of time, and ensure the industrial application of the magnetic multi-effect organic-inorganic composite amphiphilic particle.

[0009] The outer surface of the silica shell layer of the magnetic multi-effect organic-inorganic composite amphiphilic particle provided by the present application comprises a hydrophilic part and a hydrophobic part at the same time, so that the magnetic multi-effect organic-inorganic composite amphiphilic particle has amphiphilicity, has more stable emulsification characteristics compared with traditional homogeneous particles, can more stably and more widely emulsify oil-water two-phase, form a stable oil-in-water emulsion, and provide a stability basis for the manipulation of emulsion droplets.

[0010] And, the functional groups on the outer surface of the silica shell of the magnetic multi-effect organic-inorganic composite amphiphilic particle have electrostatic interactions with the partially hydrolyzed polyacrylamide, promoting the adsorption of the partially hydrolyzed polyacrylamide on the outer surface of the silica shell; and the polydopamine grafted on the amino group of the hydrophilic part further increases the adhesion of the amphiphilic particle to the partially hydrolyzed polyacrylamide, improving the effect of the amphiphilic particle on removing the partially hydrolyzed polyacrylamide in wastewater. After the adsorption and adhesion of the partially hydrolyzed polyacrylamide are achieved, due to the wetting effect of the internal structure of the amphiphilic particle on the partially hydrolyzed polyacrylamide adsorbed and adhered on the outer surface of the silica shell, the adsorption process of the partially hydrolyzed polyacrylamide into the silica shell is promoted. The PDEAEMA grafted on the inner surface of the silica shell and the surface of the magnetic Fe3O4 particle core forms a brush-like coating, increasing the specific surface area and enhancing the hydrogen bond density, while the micro-pore structure on the silica shell provides a channel for the migration and transmission of the partially hydrolyzed polyacrylamide, and the weakly acidic characteristics of the partially hydrolyzed polyacrylamide itself facilitate the transfer and adsorption of the partially hydrolyzed polyacrylamide from the outer surface of the silica shell to the PDEAEMA inside the shell. Thus, the adsorption and migration capture of the PDEAEMA to the partially hydrolyzed polyacrylamide are achieved. The magnetic multi-effect organic-inorganic composite amphiphilic particle provided in the application greatly improves the adsorption capacity and adsorption efficiency of the partially hydrolyzed polyacrylamide through the combination of the internal and external structures.

[0011] The magnetic multi-effect organic-inorganic composite amphiphilic particle provided in the application can be recycled and reused. The recycling method can be washing and extracting the used magnetic multi-effect organic-inorganic composite amphiphilic particle with a good solvent (such as ethanol) of the partially hydrolyzed polyacrylamide to remove the adsorbed partially hydrolyzed polyacrylamide, so as to realize the reuse of the magnetic multi-effect organic-inorganic composite amphiphilic particle. The pH sensitivity of PDEAEMA can also be utilized, i.e., PDEAEMA shows hydrophilic characteristics at a low pH value and shows hydrophobic characteristics at a high pH value, and this characteristic is used to realize the repeated adsorption and desorption of PDEAEMA to the partially hydrolyzed polyacrylamide, so that the magnetic multi-effect organic-inorganic composite amphiphilic particle can be reused, greatly reducing the material cost of wastewater treatment.

[0012] According to some embodiments of the application, the amino-containing silane coupling agent includes 3-aminopropyl triethoxysilane.

[0013] The modification of the silica shell outer surface with 3-aminopropyl triethoxysilane makes the hydrophilic part of the silica shell outer surface have an amino group, which can produce weak interactions with the partially hydrolyzed polyacrylamide with a carboxyl group, so as to realize the adsorption of the partially hydrolyzed polyacrylamide.

[0014] According to some embodiments of the present application, the hydrophobic part is obtained by modifying the outer surface of the silica shell with an alkyl-containing silane coupling agent.

[0015] According to some embodiments of the present application, the alkyl-containing silane coupling agent comprises n-octyltriethoxysilane.

[0016] According to some embodiments of the present application, the area of the hydrophilic part accounts for 1 / 3-2 / 3 of the total surface area of the magnetic multi-functional organic-inorganic composite amphiphilic particles.

[0017] According to some embodiments of the present application, the particle size of the magnetic multi-functional organic-inorganic composite amphiphilic particles is 100 nm < r ≤ 1000 nm.

[0018] In a second aspect, the present application provides a method for preparing magnetic multi-functional organic-inorganic composite amphiphilic particles, comprising:

[0019] S1. dispersing magnetic Fe3O4 particles and tetraethyl orthosilicate into an alcohol solvent to obtain silica-coated iron magnetic particles;

[0020] S2. dispersing the silica-coated iron magnetic particles into water, adding paraffin, heating to completely melt the paraffin, stirring and mixing, and filtering after cooling to obtain paraffin balls formed by embedding the silica-coated iron magnetic particles on the surface of the paraffin;

[0021] S3. dispersing the paraffin balls into dimethyl sulfoxide, adding an amino-containing silane coupling agent, stirring and reacting, and dispersing the obtained solid particles into an alcohol solvent to obtain hydrophilic modified particles;

[0022] S4. dispersing the hydrophilic modified particles into an alcohol solvent, adding an alkyl-containing silane coupling agent, stirring and reacting to obtain amphiphilic modified particles;

[0023] S5. mixing the amphiphilic modified particles with acetic acid for 8-12 h to obtain core-shell separated amphiphilic modified particles;

[0024] S6. dispersing the core-shell separated amphiphilic modified particles into an alcohol solvent, adding 4-(chloromethyl)phenyltrimethoxysilane for modification reaction, and then grafting with diethylaminoethyl methacrylate (DEAEMA) for grafting reaction to obtain particles grafted with polydiethylaminoethyl methacrylate;

[0025] S7. dispersing the particles grafted with polydiethylaminoethyl methacrylate into a solvent, adding dopamine, stirring and reacting, and obtaining the magnetic multi-functional organic-inorganic composite amphiphilic particles after the reaction is completed.

[0026] The preparation method of the magnetic multi-effect organic-inorganic composite amphiphilic particles provided by the application comprises the processes of silica shell wrapping, hydrophilic modification, hydrophobic modification, acid etching treatment, 4-(chloromethyl)phenyl trimethoxysilane modification, grafting of poly(diethylaminoethyl methacrylate) (PDEAEMA) and grafting of polydopamine. Specifically, magnetic Fe3O4 particles are used as carriers, tetraethyl orthosilicate is used to realize hydrolysis on the surface of the magnetic Fe3O4 particles, and a silica shell structure is formed on the magnetic Fe3O4 particles by a sol-gel process. Then, paraffin is used as an oil phase, and the silica-coated iron magnetic particles are used as solid particle emulsifiers to emulsify the oil and water phases when the temperature is higher than the phase transition temperature of paraffin, so as to form a stable water-in-paraffin emulsion. After the emulsion is cooled, the paraffin phase is solidified and separated from the water phase, so as to obtain paraffin balls in which the silica-coated iron magnetic particles are embedded on the surface of paraffin, and the silica-coated iron magnetic particles are partially embedded in paraffin and partially exposed outside paraffin. Then, the outer surface of the silica-coated iron magnetic particles exposed outside paraffin is subjected to hydrophilic modification. After the paraffin is removed, the part of the silica-coated iron magnetic particles previously protected by paraffin is exposed, and the outer surface of the part is subjected to hydrophobic modification, so as to obtain amphiphilic particles with hydrophilic and hydrophobic parts on the surface of the particles. Then, acid etching treatment is performed, so that the size of the magnetic Fe3O4 particles is reduced, the silica shell is separated from the magnetic Fe3O4 particles, and a hollow structure is formed between the core-shell structures. Further, 4-(chloromethyl)phenyl trimethoxysilane is used to realize modification of benzyl chloride 【4-(chloromethyl)phenyl】 on the surface of the magnetic Fe3O4 particles and the inner surface of the silica shell. The benzyl chloride has high activity and can be used to graft PDEAEMA through ATRP (atom transfer radical polymerization). Finally, the particles are reacted with dopamine to graft polydopamine. The magnetic multi-effect organic-inorganic composite amphiphilic particles are prepared.

[0027] In the application, in view of the characteristics that the magnetic Fe3O4 particles are not resistant to acidic solutions, tetraethyl orthosilicate is used to realize hydrolysis on the surface of the magnetic Fe3O4 particles, and a relatively dense silica shell structure is formed on the surface of the magnetic Fe3O4 particles by a sol-gel process, so as to protect the magnetic Fe3O4 particles inside. The magnetic Fe3O4 particles can resist corrosion of hydrochloric acid, sulfuric acid, nitric acid and the like for a certain period of time, which provides an important guarantee for industrial application of the magnetic particles. Moreover, the silica shell in the application is a polymer formed by hydrolysis and condensation of tetraethyl orthosilicate, and is a macromolecular skeleton composed of silicon-oxygen bonds. Although the silica shell is relatively dense, there are still intermolecular gaps in the macromolecular skeleton of SiO2 formed by the condensation reaction in the sol-gel process of hydrolysis of tetraethyl orthosilicate, which ensures the smooth progress of subsequent acid etching treatment, 4-(chloromethyl)phenyl trimethoxysilane modification and grafting of PDEAEMA.

[0028] In the present application, the magnetic Fe3O4 particles are reduced in size by acid etching, resulting in core-shell separation. This process further causes defects in the silica shell, even micro- or capillary pores, which together with the intermolecular voids in the silica shell form a micro-porous structure that provides a channel for the transport of partially hydrolyzed polyacrylamide into the interior of the silica shell. The acid etching reagent is acetic acid, which allows the etching to proceed slowly, ensuring that the etching process is controllable, and makes the surface of the magnetic Fe3O4 particle core smoother. If hydrochloric acid, sulfuric acid, or the like is used, it is difficult to control the etching process, and it is easy to cause excessive etching, resulting in a particle with too weak a magnetic property or even complete loss of magnetic property.

[0029] According to some embodiments of the present application, the alcohol solvent includes at least one of methanol, ethanol, propanol, butanol, isopropanol, and cyclohexanol.

[0030] According to some embodiments of the present application, the stirring speed in step S2 is 1000-5000 rpm.

[0031] In the present application, the stirring speed in step S2 directly affects the emulsification process of the particle emulsifier (silica-coated iron magnetic particles), and directly leads to the stability of the particle emulsifier to the emulsion interface. When the stirring speed is less than 1000 rpm, the stirring speed is too low, the particle emulsifier is difficult to deliver to the interface, and the interface cannot be stabilized, and the emulsion is easy to break; when the stirring speed is greater than 5000 rpm, the stirring speed is too high, the particle emulsifier is forced to be pulled at the interface, and the interface is easy to lose stability and break. Therefore, in order to ensure emulsification and interface stability, the stirring speed in step S2 is preferably controlled to be 1000-5000 rpm.

[0032] According to some embodiments of the present application, the stirring time in step S2 is 3-5 min.

[0033] According to some embodiments of the present application, the amino-containing silane coupling agent includes 3-aminopropyl triethoxysilane.

[0034] The local hydrophilic modification of the outer surface of the silica-coated iron magnetic particles using 3-aminopropyl triethoxysilane is carried out in dimethyl sulfoxide. The modification is achieved by a sol-gel process on the outer surface of the silica-coated iron magnetic particles exposed to paraffin, and the amino group is modified on one side of the outer surface of the silica-coated iron magnetic particles, which can realize the adsorption of partially hydrolyzed polyacrylamide.

[0035] According to some embodiments of the present application, the alkyl-containing silane coupling agent includes n-octyl triethoxysilane.

[0036] The local hydrophobic modification of the outer surface of the silicon-coated iron magnetic particles by using n-octyl triethoxysilane is to remove the paraffin by using an alcohol solvent, to expose the part of the silicon-coated iron magnetic particles embedded in the paraffin and protected, and to realize sol-gel composite on the surface of the silicon-coated iron magnetic particles from the exposed part by the hydrolysis process of n-octyl triethoxysilane, and to modify n-octyl on the other side of the outer surface of the silicon-coated iron magnetic particles.

[0037] According to some embodiments of the present application, the mass ratio of the magnetic Fe3O4 particles and tetraethyl orthosilicate is 1:(0.1-1).

[0038] According to some embodiments of the present application, the mass ratio of the magnetic Fe3O4 particles and the paraffin is 1:(10-200).

[0039] According to some embodiments of the present application, the mass ratio of the paraffin and water is 1:(2-10).

[0040] According to some embodiments of the present application, the mass ratio of the magnetic Fe3O4 particles and the amino-containing silane coupling agent is 1:(0.001-0.01).

[0041] According to some embodiments of the present application, the mass ratio of the magnetic Fe3O4 particles and the alkyl-containing silane coupling agent is 1:(0.001-0.01).

[0042] According to some embodiments of the present application, the mass ratio of the magnetic Fe3O4 particles and the 4-(chloromethyl)phenyl trimethoxysilane is 1:(0.001-0.01).

[0043] According to some embodiments of the present application, the mass ratio of the magnetic Fe3O4 particles and the diethylaminoethyl methacrylate is 1:(0.02-0.1).

[0044] According to some embodiments of the present application, the mass ratio of the magnetic Fe3O4 particles and the dopamine is 1:(0.001-0.01).

[0045] According to some embodiments of the present application, the particle size of the magnetic Fe3O4 particles is 100-500 nm.

[0046] According to some embodiments of the present application, the particle size ratio of the magnetic Fe3O4 particles to the core of the magnetic Fe3O4 particles is 100:(10-99).

[0047] In the present application, if the ratio of the particle size of the magnetic Fe3O4 particles to the particle size of the core of the magnetic Fe3O4 particles is less than 100:99, it means that the gap between the silica shell and the core of the magnetic Fe3O4 particles is too small, which will affect the adsorption capacity of the magnetic multi-effect organic-inorganic composite amphiphilic particles to the partially hydrolyzed polyacrylamide; if the ratio of the particle size of the magnetic Fe3O4 particles to the particle size of the core of the magnetic Fe3O4 particles is greater than 100:10, it means that the size of the core of the magnetic Fe3O4 particles is too small, which will cause serious magnetic decay and make it difficult to realize the magnetic control of the external magnetic field.

[0048] According to some embodiments of the present application, the grafting reaction comprises: dissolving cuprous chloride and 2,2-bipyridine in a solvent, adding the modified amphiphilic modified particles and diethylaminoethyl methacrylate after the reaction treatment, and stirring under a nitrogen atmosphere and at a temperature of 60-100°C.

[0049] According to some embodiments of the present application, the solvent used in the grafting reaction comprises at least one of water, tetrahydrofuran (THF), and N,N-dimethylformamide (DMF).

[0050] According to some embodiments of the present application, the solvent used for dispersing the particles of the grafted polymethyl methacrylate diethylaminoethyl comprises at least one of water, tetrahydrofuran (THF), and N,N-dimethylformamide (DMF).

[0051] According to some embodiments of the present application, in the step S1, the magnetic Fe3O4 particles and tetraethyl orthosilicate are dispersed in an alcohol solvent by ultrasonic and stirring for 12-24 hours, preferably, the ultrasonic frequency is 60-80 Hz and / or the stirring speed is 50-100 rpm.

[0052] According to some embodiments of the present application, in the step S2, the silicon-coated iron magnetic particles are dispersed in water by ultrasonic and stirring, preferably, the ultrasonic frequency is 60-80 Hz and / or the stirring speed is 50-100 rpm.

[0053] According to some embodiments of the present application, in the step S3, the paraffin balls are dispersed in dimethyl sulfoxide by stirring, preferably, the stirring speed is 50-100 rpm.

[0054] According to some embodiments of the present application, the stirring reaction time in the step S3 is 5-6 hours.

[0055] According to some embodiments of the present application, in the step S4, the hydrophilic modified particles are dispersed in an alcohol solvent by ultrasonic and stirring, preferably, the ultrasonic frequency is 60-80 Hz and / or the stirring speed is 200-300 rpm.

[0056] According to some embodiments of the present application, the stirring reaction time in step S4 is 5-6h.

[0057] According to some embodiments of the present application, the mixing of the amphiphilic modified particles with acetic acid for 8-12h in step S5 comprises: dispersing the amphiphilic modified particles in water, adding acetic acid, and mixing for 8-12h by ultrasonic and stirring, preferably, the ultrasonic frequency is 60-80Hz and / or the stirring speed is 50-100rpm.

[0058] According to some embodiments of the present application, the stirring reaction time in step S7 is 5-6h.

[0059] In a third aspect, the present application provides a magnetic multi-effect organic-inorganic composite amphiphilic particle, which is prepared by the method of the second aspect.

[0060] In a fourth aspect, the present application provides an application of the magnetic multi-effect organic-inorganic composite amphiphilic particle of the first aspect or the magnetic multi-effect organic-inorganic composite amphiphilic particle of the third aspect in treating oil-containing wastewater containing partially hydrolyzed polyacrylamide.

[0061] The present application has at least the following advantages:

[0062] (1) The magnetic multi-effect organic-inorganic composite amphiphilic particle provided by the present application has excellent emulsifying performance. The liquid droplets emulsified by the magnetic multi-effect organic-inorganic composite amphiphilic particle can be controlled by an external magnetic field, realizing the enrichment and migration of oil droplets, and thus realizing oil-water separation.

[0063] (2) The magnetic multi-effect organic-inorganic composite amphiphilic particle provided by the present application has a core-shell separation structure. The poly (dimethylamino ethyl methacrylate) grafted in the cavity between the core and the shell has a good adsorption effect on partially hydrolyzed polyacrylamide. In addition, the amino group on the surface of the particle and the polydopamine grafted thereon also have adsorption properties, which can further improve the adsorption effect on partially hydrolyzed polyacrylamide, thereby realizing efficient treatment of oil-containing wastewater containing partially hydrolyzed polyacrylamide in one step.

[0064] (3) The magnetic multi-effect organic-inorganic composite amphiphilic particle provided by the present application can be repeatedly used, and the adsorption capacity for partially hydrolyzed polyacrylamide does not decrease significantly, which can greatly reduce the material cost of wastewater treatment.

[0065] (4) The preparation method of the magnetic multi-effect organic-inorganic composite amphiphilic particle provided by the present application is simple, the raw material cost is low and easy to obtain, and industrial ton-level batch production can be realized. DETAILED DESCRIPTION

[0066] In order to make the technical problems, technical solutions and beneficial effects of the present application clearer, the present application will be further described in detail below in combination with specific examples. It should be understood that the specific examples described herein are only used to illustrate the present patent and do not limit the protection scope of the present application in any way.

[0067] Unless otherwise defined, the technical terms used in the following examples have the same meanings as commonly understood by those skilled in the art to which the present application belongs. The reagents used in the following examples are conventional biochemical reagents unless otherwise specified. The raw materials, instruments and equipment used in the following examples can be purchased on the market or obtained by existing methods. The reagent amount is the amount used in conventional experimental operations unless otherwise specified. The experimental methods are conventional methods unless otherwise specified.

[0068] Example 1

[0069] S1. 2.0 g of magnetic Fe3O4 particles (particle size of 0.2 μm) were dispersed in 200 mL of ethanol, and 1.0 g of tetraethyl orthosilicate was added, with the addition of 60 Hz ultrasonic and 100 rpm overhead stirring, to promote the dispersion of the magnetic Fe3O4 particles. The ultrasonic and stirring were maintained for 12 h, and the silicon-coated iron magnetic particles were separated.

[0070] S2. The silicon-coated iron magnetic particles were dispersed in 200 mL of water, and 60 Hz ultrasonic and 100 rpm overhead stirring were added to promote the dispersion of the silicon-coated iron magnetic particles. The water temperature was raised to 80℃, and 20 g of paraffin wax (phase transition temperature of 52℃) was added. The stirring was continued until the paraffin wax was completely melted. The ultrasonic was turned off and the stirring speed was increased to 2000 rpm for 3 min. The stirring and heating were stopped, and the sample was cooled to room temperature. The solidified paraffin wax balls were filtered out and separated from the water. The paraffin wax balls were dispersed on filter paper and naturally air-dried to obtain paraffin wax ball powder formed by the silicon-coated iron magnetic particles embedded on the surface of the paraffin wax.

[0071] S3. The paraffin wax ball powder was dispersed in 100 mL of dimethyl sulfoxide, and a top stirrer was used to slowly stir the dispersion at a speed of 50 rpm. 20 mg of 3-aminopropyl triethoxysilane was added to the dispersion, and the stirring was continued for 6 h. The paraffin wax ball powder and the solvent were separated by an external magnetic field, and the paraffin wax ball powder was air-dried in a natural state. The paraffin wax ball powder was again dispersed in 100 mL of ethanol, and the paraffin wax was dissolved. The solid particles were separated by an external magnetic field to obtain Fe3O4@SiO2-NH2 particles with amino-modified surfaces on one side.

[0072] S4. Disperse Fe3O4@SiO2-NH2 particles into 100 mL ethanol, stir the dispersion with an overhead stirrer at 300 rpm, while adding 60 Hz ultrasound. Add 20 mg of n-octyltriethoxysilane to the dispersion, continue stirring for 6 h, separate the solid particles using an external magnetic field, to obtain C8-Fe3O4@SiO2-NH2 particles.

[0073] S5. Disperse C8-Fe3O4@SiO2-NH2 particles in 100 mL water, add 2 mL of acetic acid, stir the dispersion with an overhead stirrer at 100 rpm for 10 h, while adding 60 Hz ultrasound, to obtain core-shell separated C8-Fe3O4@SiO2-NH2 particles;

[0074] S6. Disperse core-shell separated C8-Fe3O4@SiO2-NH2 particles in 100 mL ethanol, add 10 mg of 4-(chloromethyl)phenyltrimethoxysilane, stir at 100 rpm for 12 h, to obtain modified C8-Fe3O4@SiO2-NH2 particles; dissolve 0.02 g of cuprous chloride and 0.02 g of 2,2-bipyridine in 50 mL of DMF, add the above modified C8-Fe3O4@SiO2-NH2 particles, add 0.1 g of DEAEMA, while purging N2 to remove oxygen for 30 min, warm to 80 °C, stir at 100 rpm for 3 h, to obtain particles grafted with poly (diethylaminoethyl methacrylate);

[0075] S7. Disperse the particles grafted with poly (diethylaminoethyl methacrylate) into a solvent, add 20 mg of dopamine, stir the reaction for 6 h, to obtain magnetic multi-functional organic-inorganic composite amphiphilic particles after the reaction is completed.

[0076] Example 2

[0077] S1. Disperse 2.0 g of magnetic Fe3O4 particles (particle size of 0.2 μm) into 200 mL of ethanol, while adding 0.3 g of tetraethyl orthosilicate, add 80 Hz ultrasound and 80 rpm overhead stirring, maintain the ultrasound and stirring to promote the dispersion of the magnetic Fe3O4 particles, continue for 24 h, to separate the silicon-coated iron magnetic particles.

[0078] S2. Disperse the Si-coated Fe magnetic particles into 200 mL water, while adding 80 Hz ultrasound and 80 rpm overhead stirring, keep the ultrasound and stirring to promote the dispersion of the Si-coated Fe magnetic particles. Increase the water temperature to 80 °C, add 50 g paraffin wax (phase transition temperature is 52 °C), continue stirring until the paraffin wax is completely melted. Turn off the ultrasound and increase the stirring speed to 1000 rpm, continue stirring for 5 min. Stop stirring and heating, cool the sample to room temperature, filter out the solidified paraffin wax balls, separate them from the water. Disperse the paraffin wax balls on filter paper, air dry to obtain paraffin wax ball powder with Si-coated Fe magnetic particles embedded in the surface of the paraffin wax.

[0079] S3. Disperse the paraffin wax ball powder into 100 mL dimethyl sulfoxide, slowly stir the dispersion with an overhead stirrer at 80 rpm. Add 3 mg of 3-aminopropyltriethoxysilane to the dispersion and continue stirring for 5 h. Use an external magnetic field to separate the paraffin wax ball powder and the solvent, and air dry the paraffin wax ball powder. Disperse the paraffin wax ball powder in 100 mL ethanol again, dissolve the paraffin wax, separate the solid particles using an external magnetic field, and obtain Fe3O4@SiO2-NH2 particles with amino groups modified on one side of the surface.

[0080] S4. Disperse the Fe3O4@SiO2-NH2 particles into 100 mL ethanol, stir the dispersion with an overhead stirrer at 300 rpm, while adding 80 Hz ultrasound. Add 3 mg of n-octyltriethoxysilane to the dispersion and continue stirring for 5 h, separate the solid particles using an external magnetic field, and obtain C8-Fe3O4@SiO2-NH2 particles.

[0081] S5. Disperse the C8-Fe3O4@SiO2-NH2 particles in 100 mL water, add 2 mL of acetic acid, stir the dispersion with an overhead stirrer at 80 rpm for 8 h, while adding 80 Hz ultrasound, to obtain C8-Fe3O4@SiO2-NH2 particles with core-shell separation;

[0082] S6. Disperse the C8-Fe3O4@SiO2-NH2 particles with core-shell separation in 100 mL ethanol, add 3 mg of 4-(chloromethyl)phenyltrimethoxysilane, and stir at 80 rpm for 12 h to obtain modified C8-Fe3O4@SiO2-NH2 particles; dissolve 0.02 g of cuprous chloride and 0.02 g of 2,2-bipyridine in 50 mL of DMF, add the above modified C8-Fe3O4@SiO2-NH2 particles, add 0.04 g of DEAEMA, and simultaneously introduce N2 to remove oxygen for 30 min, increase the temperature to 80 °C, and stir at 80 rpm for 3 h to obtain particles grafted with poly(diethylaminoethyl methacrylate);

[0083] S7. The grafted poly (diethylaminoethyl methacrylate) particles were dispersed in solvent, 3 mg dopamine was added, and the reaction was stirred for 6 h. After the reaction was completed, magnetic multi-functional organic-inorganic composite amphiphilic particles were obtained.

[0084] Example 3

[0085] S1. 2.0 g of magnetic Fe3O4 particles (particle size of 0.2 μm) were dispersed in 200 mL of ethanol, and 2.0 g of tetraethyl orthosilicate was added. An 80 Hz ultrasonic wave and a 60 rpm overhead stirrer were applied to promote the dispersion of the magnetic Fe3O4 particles. The ultrasonic wave and stirring were maintained for 12 h. The silicon-coated iron magnetic particles were separated.

[0086] S2. The silicon-coated iron magnetic particles were dispersed in 200 mL of water, and an 80 Hz ultrasonic wave and a 60 rpm overhead stirrer were applied to promote the dispersion of the silicon-coated iron magnetic particles. The water temperature was raised to 80 °C, and 20 g of paraffin wax (phase transition temperature of 52 °C) was added. The stirring was continued until the paraffin wax was completely melted. The ultrasonic wave was turned off, and the stirring speed was increased to 5000 rpm for 4 min. The stirring and heating were stopped, and the sample was cooled to room temperature. The solidified paraffin wax spheres were filtered out and separated from the water. The paraffin wax spheres were dispersed on filter paper and naturally air-dried to obtain paraffin wax sphere powder in which the silicon-coated iron magnetic particles were embedded on the surface of the paraffin wax.

[0087] S3. The paraffin wax sphere powder was dispersed in 100 mL of dimethyl sulfoxide, and the dispersion was slowly stirred using an overhead stirrer at a speed of 60 rpm. 10 mg of 3- aminopropyltriethoxysilane was added to the dispersion, and the stirring was continued for 6 h. The paraffin wax sphere powder and the solvent were separated using an external magnetic field, and the paraffin wax sphere powder was air-dried in a natural state. The paraffin wax sphere powder was again dispersed in 100 mL of ethanol, and the paraffin wax was dissolved. The solid particles were separated using an external magnetic field to obtain Fe3O4@SiO2-NH2 particles with amino groups modified on one side of the surface.

[0088] S4. The Fe3O4@SiO2-NH2 particles were dispersed in 100 mL of ethanol, and the dispersion was stirred using an overhead stirrer at a speed of 200 rpm, while an 80 Hz ultrasonic wave was applied. 10 mg of n-octyltriethoxysilane was added to the dispersion, and the stirring was continued for 6 h. The solid particles were separated using an external magnetic field to obtain C8-Fe3O4@SiO2-NH2 particles.

[0089] S5. The C8-Fe3O4@SiO2-NH2 particles were dispersed in 100 mL of water, and 2 mL of acetic acid was added. The dispersion was stirred using an overhead stirrer at a speed of 60 rpm for 12 h, while an 80 Hz ultrasonic wave was applied to obtain C8-Fe3O4@SiO2-NH2 particles with a core-shell separation.

[0090] S6. The C8-Fe3O4@SiO2-NH2 particles were dispersed in 100 mL of ethanol, 15 mg of 4-(chloromethyl)phenyltrimethoxysilane was added, and stirring was performed at 60 rpm for 12 h to obtain modified C8-Fe3O4@SiO2-NH2 particles; 0.02 g of cuprous chloride and 0.02 g of 2,2-bipyridine were dissolved in 50 mL of DMF, the modified C8-Fe3O4@SiO2-NH2 particles were added, 0.2 g of DEAEMA was added, and oxygen was removed by N2 for 30 min; the temperature was increased to 80°C, and stirring was performed at 60 rpm for 3 h to obtain particles grafted with poly (diethylaminoethyl methacrylate) ;

[0091] S7. The particles grafted with poly (diethylaminoethyl methacrylate) were dispersed in a solvent, 10 mg of dopamine was added, and stirring was performed for 6 h to obtain magnetic multi-functional organic-inorganic composite amphiphilic particles.

[0092] Example 4

[0093] S1. 2.0 g of magnetic Fe3O4 particles (0.2 μm in size) were dispersed in 200 mL of ethanol, 1.0 g of tetraethyl orthosilicate was added, 60 Hz ultrasonic and 100 rpm overhead stirring were added, the ultrasonic and stirring were maintained to promote dispersion of the magnetic Fe3O4 particles, and the process was continued for 12 h to obtain silicon-coated iron magnetic particles.

[0094] S2. The silicon-coated iron magnetic particles were dispersed in 200 mL of water, 60 Hz ultrasonic and 100 rpm overhead stirring were added, the ultrasonic and stirring were maintained to promote dispersion of the silicon-coated iron magnetic particles, the water temperature was increased to 80°C, 20 g of paraffin wax (52°C in phase transition temperature) was added, and stirring was continued until the paraffin wax was completely melted. The ultrasonic was turned off and the stirring speed was increased to 500 rpm. If the stirring speed is too low, the particles cannot be delivered to the oil-water interface by mechanical force, the silicon-coated iron magnetic particles cannot be stably arranged at the oil-water interface, and the oil-water two phases cannot be stably emulsified, so the water phase and the oil phase are still two phases, and the silicon-coated iron magnetic particle-embedded paraffin wax powder cannot be prepared.

[0095] Example 5

[0096] S1. 2.0 g of magnetic Fe3O4 particles (0.2 μm in size) were dispersed in 200 mL of ethanol, 1.0 g of tetraethyl orthosilicate was added, 60 Hz ultrasonic and 100 rpm overhead stirring were added, the ultrasonic and stirring were maintained to promote dispersion of the magnetic Fe3O4 particles, and the process was continued for 12 h to obtain silicon-coated iron magnetic particles.

[0097] S2. Disperse the silica-coated magnetic particles into 200 mL water while adding 60 Hz ultrasound and 100 rpm overhead stirring, keeping the ultrasound and stirring to promote dispersion of the silica-coated magnetic particles. Increase the water temperature to 80 °C and add 20 g of paraffin wax (phase transition temperature of 52 °C) and continue stirring until the paraffin wax is completely melted. Turn off the ultrasound and increase the stirring speed to 6000 rpm. Due to the high stirring speed, the silica-coated magnetic particles are mechanically delivered to the oil-water interface to achieve emulsification, but the fast mechanical stirring causes the particles to peel off at the interface, resulting in interface instability, demulsification, and failure to produce paraffin wax spheres powder with silica-coated magnetic particles embedded in the paraffin wax surface.

[0098] Comparative Example 1

[0099] S1. Disperse 2.0 g of magnetic Fe3O4 particles (particle size of 0.2 pm) into 200 mL of ethanol while adding 1.0 g of tetraethyl orthosilicate, and add 60 Hz ultrasound and 100 rpm overhead stirring to promote dispersion of the magnetic Fe3O4 particles. Continue for 12 h, and separate the silica-coated magnetic particles.

[0100] S2. Disperse the silica-coated magnetic particles into 200 mL water while adding 60 Hz ultrasound and 100 rpm overhead stirring, keeping the ultrasound and stirring to promote dispersion of the silica-coated magnetic particles. Increase the water temperature to 80 °C and add 20 g of paraffin wax (phase transition temperature of 52 °C) and continue stirring until the paraffin wax is completely melted. Turn off the ultrasound and increase the stirring speed to 2000 rpm for 3 min. Stop stirring and heating, and cool the sample to room temperature. Filter out the solidified paraffin wax spheres, and separate them from the water. Disperse the paraffin wax spheres on filter paper and air dry to obtain paraffin wax spheres powder with silica-coated magnetic particles embedded in the paraffin wax surface.

[0101] S3. Disperse the paraffin wax spheres powder into 100 mL of dimethyl sulfoxide, and use a overhead stirrer to slowly stir the dispersion at a speed of 50 rpm. Add 20 mg of 3- aminopropyltriethoxysilane to the dispersion and continue stirring for 6 h. Use an external magnetic field to separate the paraffin wax spheres powder and the solvent, and air dry the paraffin wax spheres powder. Disperse the paraffin wax spheres powder in 100 mL of ethanol to dissolve the paraffin wax, and use an external magnetic field to separate the solid particles to obtain Fe3O4@SiO2-NH2 particles with amino groups modified on one side of the surface.

[0102] S4. Disperse the Fe3O4@SiO2-NH2 particles into 100 mL of ethanol, and use a overhead stirrer to stir the dispersion at a speed of 300 rpm while adding 60 Hz ultrasound. Add 20 mg of n-octyltriethoxysilane to the dispersion and continue stirring for 6 h. Use an external magnetic field to separate the solid particles to obtain C8-Fe3O4@SiO2-NH2 particles;

[0103] S5. The C8-Fe3O4@SiO2-NH2 particles were dispersed in solvent, 20 mg dopamine was added, and the reaction was stirred for 6 h to obtain the particles.

[0104] Comparative Example 2

[0105] S1. 2.0 g of magnetic Fe3O4 particles (particle size of 0.2 μm) were dispersed in 200 mL of ethanol, and 1.0 g of tetraethyl orthosilicate was added. The dispersion was maintained for 12 h with the aid of 60 Hz ultrasonic and 100 rpm overhead stirring to promote the dispersion of the magnetic Fe3O4 particles. The silicon-coated iron magnetic particles were separated.

[0106] S2. The silicon-coated iron magnetic particles were dispersed in 100 mL of water, and 2 mL of acetic acid was added. The dispersion was stirred for 10 h at 100 rpm with the aid of an overhead stirrer and 60 Hz ultrasonic to obtain the core-shell separated silicon-coated iron magnetic particles.

[0107] S3. The core-shell separated silicon-coated iron magnetic particles were dispersed in 100 mL of ethanol, and 10 mg of 4-(chloromethyl)phenyltrimethoxysilane was added. The dispersion was stirred for 12 h at 100 rpm to obtain the modified silicon-coated iron magnetic particles. 0.02 g of cuprous chloride and 0.02 g of 2,2-bipyridine were dissolved in 50 mL of DMF, and the modified silicon-coated iron magnetic particles were added. 0.1 g of DEAEMA was added, and the system was deoxygenated by N2 for 30 min. The temperature was raised to 80 °C, and the system was stirred at 100 rpm for 3 h. The particles were obtained after the reaction.

[0108] Comparative Example 3

[0109] The particles were prepared according to the preparation method of Example 1, except that acetic acid was replaced by an equal volume of dilute hydrochloric acid (PH 6).

[0110] Comparative Example 4

[0111] The particles were prepared according to the preparation method of Example 1, except that acetic acid was replaced by an equal volume of sulfuric acid.

[0112] Performance Evaluation

[0113] (1) The particle size of the particles of each example and comparative example was measured by scanning electron microscopy, and the results are shown in the following table:

[0114] Group Particle diameter (nm) Example 1 260 Example 2 212 Example 3 260 Comparative Example 1 260 Comparative Example 2 220 Comparative Example 3 260 Comparative Example 4 260

[0115] (2) Wastewater treatment effect

[0116] 1 kg of each of the particles prepared in the examples and the comparative examples was added to 10 t of oil-containing wastewater containing partially hydrolyzed polyacrylamide (COD value: 2020, oil content: 52.3 mg / L, partially hydrolyzed polyacrylamide content: 103.05 mg / L), and the oil-containing wastewater was emulsified by using a shearing machine to stir at 1000 rpm for 1 min; then the migration and enrichment of the oil droplets emulsified by the magnetic particles were achieved by external magnetic field control. The treated wastewater was detected, and the detection methods are shown in the following table:

[0117]

[0118] The detection results are shown in the following table:

[0119]

[0120] (III) Recycling performance

[0121] The magnetic multi-effect organic-inorganic composite amphiphilic particles were washed and regenerated by using a solvent method, so as to realize the recycling of the magnetic multi-effect organic-inorganic composite amphiphilic particles. The specific treatment method includes: collecting the magnetic multi-effect organic-inorganic composite amphiphilic particles prepared in Example 1 after wastewater treatment, washing with ethanol, and the mass ratio of ethanol to the amphiphilic particles is 10:1; after washing, the particles are treated by freeze-drying to obtain regenerated particles.

[0122] The regenerated particles are used to repeat the treatment process of the oil-containing wastewater containing partially hydrolyzed polyacrylamide in (II) above, and the indicators of the treated wastewater are similar to the treatment effect of the magnetic multi-effect organic-inorganic composite amphiphilic particles of Example 1 in the first wastewater treatment. The recycling number of the magnetic multi-effect organic-inorganic composite amphiphilic particles can reach more than 100 times, and the removal effect of COD, oil and partially hydrolyzed polyacrylamide will not be significantly deteriorated.

[0123] It should be noted that the above examples are only used to explain the present application and do not constitute any limitation on the present application. The present application is described by referring to typical examples, but it should be understood that the words used therein are descriptive and explanatory words, rather than limiting words. The present application can be modified as specified within the scope of the claims of the present application, and the present application can be revised without departing from the scope and spirit of the present application. Although the present application described therein relates to specific methods, materials and examples, it does not mean that the present application is limited to the specific examples disclosed therein, on the contrary, the present application can be extended to all other methods and applications with the same function.

Claims

1. A magnetic multi-functional organic-inorganic composite amphiphilic particle, characterized in that: The invention comprises a core-shell separated magnetic Fe3O4 particle core and a silica shell; the outer surface of the silica shell comprises a hydrophilic portion and a hydrophobic portion, the hydrophilic portion is modified by using an amino-containing silane coupling agent to impart amino groups to the outer surface of the silica shell, and the amino groups are grafted with polydopamine; polydiethylaminoethyl methacrylate is grafted onto the inner surface of the silica shell and the surface of the magnetic Fe3O4 particle core, and the silica shell has a microporous structure.

2. The magnetic multi-functional organic-inorganic composite amphiphilic particles according to claim 1, characterized in that: The amino-containing silane coupling agent includes 3-aminopropyltriethoxysilane; And / or, the hydrophobic portion is obtained by modifying the outer surface of the silica shell with an alkyl-containing silane coupling agent; And / or, the particle size of the magnetic multi-functional organic-inorganic composite amphiphilic particles is 100 nm<r≤1000 nm.

3. The magnetic multi-functional organic-inorganic composite amphiphilic particles according to claim 2, characterized in that: The alkyl-containing silane coupling agent includes n-octyltriethoxysilane.

4. A method for preparing magnetic multi-functional organic-inorganic composite amphiphilic particles, characterized in that: include: S1. Dispersing magnetic Fe₃O₄ particles and ethyl orthosilicate in an alcohol solvent to obtain silicon-coated iron magnetic particles; S2. Disperse the silicon-coated iron magnetic particles in water, add paraffin wax, heat until the paraffin wax is completely melted, stir and mix, cool, and filter to obtain paraffin wax spheres formed by the silicon-coated iron magnetic particles embedded in the paraffin wax. S3. Dispersing the paraffin wax spheres in dimethyl sulfoxide, adding an amino-containing silane coupling agent, stirring to react, and then dispersing the resulting solid particles in an alcohol solvent to obtain hydrophilically modified particles. S4. Dispersing the hydrophilic modified particles in an alcohol solvent, adding an alkyl-containing silane coupling agent, and stirring to react to obtain amphiphilic modified particles; S5. Mixing the amphiphilic modified particles with acetic acid for 8-12 hours to obtain core-shell separated amphiphilic modified particles; S6. Dispersing the core-shell separated amphiphilic modified particles in an alcohol solvent, adding 4-(chloromethyl)phenyltrimethoxysilane to cause a modification reaction; then grafting with diethylaminoethyl methacrylate to obtain particles grafted with polydiethylaminoethyl methacrylate; S7. Dispersing the grafted polydiethylaminoethyl methacrylate particles in a solvent, adding dopamine, and stirring to react, and obtaining the magnetic multi-functional organic-inorganic composite amphiphilic particles after the reaction is completed.

5. The preparation method according to claim 4, characterized in that The stirring and mixing speed in step S2 is 1000-5000 rpm.

6. The preparation method according to claim 5, characterized in that The stirring and mixing time in step S2 is 3 to 5 minutes.

7. The preparation method according to any one of claims 4 to 6, characterized in that The amino-containing silane coupling agent includes 3-aminopropyltriethoxysilane; And / or, the alkyl-containing silane coupling agent includes n-octyltriethoxysilane.

8. The preparation method according to any one of claims 4 to 6, characterized in that The mass ratio of the magnetic Fe3O4 particles to tetraethyl orthosilicate is 1:(0.1~1); and / or, the mass ratio of the magnetic Fe3O4 particles to the paraffin wax is 1:(10-200); and / or, the mass ratio of the magnetic Fe3O4 particles to the amino-containing silane coupling agent is 1:(0.001-0.01); and / or, the mass ratio of the magnetic Fe3O4 particles to the alkyl-containing silane coupling agent is 1:(0.001-0.01); and / or, the mass ratio of the magnetic Fe3O4 particles to the 4-(chloromethyl)phenyltrimethoxysilane is 1:(0.001-0.01); and / or, the mass ratio of the magnetic Fe3O4 particles to the diethylaminoethyl methacrylate is 1:(0.02-0.1); And / or, the mass ratio of the magnetic Fe3O4 particles to the dopamine is 1:(0.001-0.01).

9. The preparation method according to any one of claims 4 to 6, characterized in that The particle size of the magnetic Fe3O4 particles is 100-500 nm; And / or, the particle size ratio of the magnetic Fe3O4 particles to the magnetic Fe3O4 particle core is 100:(10~99).

10. The preparation method according to any one of claims 4 to 6, characterized in that: The grafting reaction comprises: dissolving cuprous chloride and 2,2-bipyridine in a solvent, adding amphiphilic modified particles treated by the modification reaction and diethylaminoethyl methacrylate, and stirring the reaction under a nitrogen atmosphere at 60-100° C.

11. A magnetic multi-functional organic-inorganic composite amphiphilic particle prepared by the preparation method according to any one of claims 4 to 10.

12. Use of the magnetic multifunctional organic-inorganic composite amphiphilic particles according to any one of claims 1 to 3 or the magnetic multifunctional organic-inorganic composite amphiphilic particles according to claim 11 in the treatment of oily wastewater containing partially hydrolyzed polyacrylamide.

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