Magnetic multi-effect titanium-encased iron parent particle, preparation method and application thereof

Abstract

The present application relates to sewage treatment technical field, provide a kind of magnetic multi-effect titanium coated iron bipolar particles and its preparation method and application.The particle includes magnetic Fe3O4 particle core and the shell separation of TiO2 shell with magnetic Fe3O4 particle core, the outer surface of TiO2 shell includes hydrophilic part and hydrophobic part, the inner surface of TiO2 shell and the surface of magnetic Fe3O4 particle core are grafted with poly (dimethylamino ethyl methacrylate), and TiO2 shell has micro-pore structure.The particle provided by the present application has excellent emulsifying performance, and the liquid drop stabilized by the particle can be controlled by external magnetic field, to realize the enrichment and migration of oil drop, so as to realize oil-water separation;Meanwhile, it can selectively adsorb part of hydrolyzed polyacrylamide, and can efficiently treat oil-containing sewage containing part of hydrolyzed polyacrylamide in one step;The TiO2 shell on the surface of the particle can effectively improve the acid resistance and alkali resistance of the bipolar particle.

Description

TECHNICAL FIELD

[0001] The present application relates to the sewage treatment technical field, more particularly, to a magnetic multi-effect titanium-encapsulated iron bipolar particle and a preparation method and application thereof. BACKGROUND

[0002] Polymer flooding is an oil displacement method in which a small amount of water-soluble polymer is added to the injected water to improve the mobility ratio and increase the sweep efficiency by increasing the viscosity of the water phase and reducing the permeability of the water phase, thereby improving the oil recovery rate. It has become one of the main methods for tertiary oil recovery in high-water-content oilfields. Partially hydrolyzed polyacrylamide is a good polymer for polymer flooding, but the sewage generated by using partially hydrolyzed polyacrylamide for oil recovery is more difficult to treat because it contains partially hydrolyzed polyacrylamide. The existing treatment methods generally require multiple steps to achieve the treatment of oil-containing sewage containing partially hydrolyzed polyacrylamide to meet the standards. The treatment method is complex and costly. Therefore, it is urgent to develop a treatment method for oil-containing sewage containing partially hydrolyzed polyacrylamide that is simple in operation steps and good in removal of partially hydrolyzed polyacrylamide. SUMMARY

[0003] The present application aims to provide a magnetic multi-effect titanium-encapsulated iron bipolar particle and a preparation method thereof to solve the technical problem of the complexity of the existing treatment method for oil-containing sewage containing partially hydrolyzed polyacrylamide.

[0004] To achieve the above-mentioned purpose, the technical solution adopted by the present application is as follows:

[0005] In a first aspect, the present application provides a magnetic multi-effect titanium-encapsulated iron bipolar particle, which comprises a magnetic Fe3O4 particle core and a titanium dioxide shell layer separated from the core-shell of the magnetic Fe3O4 particle core. The outer surface of the titanium dioxide shell layer comprises a hydrophilic portion and a hydrophobic portion. The inner surface of the titanium dioxide shell layer and the surface of the magnetic Fe3O4 particle core are grafted with poly (diethylaminoethyl methacrylate) (PDEAEMA). The titanium dioxide shell layer has a micro-pore structure.

[0006] It should be noted that the "micro-pore structure" in the present application includes intermolecular voids in the titanium dioxide macromolecular skeleton and defects generated during the core-shell separation of the titanium dioxide shell layer from the magnetic Fe3O4 particle core, even micro-pores and capillary pores with a pore size of 0.5-50 nm.

[0007] The magnetic multi-functional titanium-coated iron amphiphilic particles provided by the present invention are coated with a titanium dioxide shell layer on the outside of the magnetic Fe3O4 particle core, which can protect the magnetic Fe3O4 particle core and resist the corrosion of the magnetic Fe3O4 particle core by hydrochloric acid, sulfuric acid, nitric acid or various alkaline reagents within a certain period of time, so that the magnetic multi-functional titanium-coated iron amphiphilic particles can be used to treat acidic or alkaline wastewater.

[0008] The outer surface of the titanium dioxide shell of the magnetic multi-functional titanium-coated iron amphiphilic particles provided by the present invention includes both hydrophilic and hydrophobic parts, which makes the magnetic multi-functional titanium-coated iron amphiphilic particles amphiphilic. Compared with traditional homogeneous particles, they have more stable emulsification properties and can emulsify oil and water phases more stably and more widely to form a stable water-in-oil emulsion, providing a stability basis for the manipulation of emulsion droplets.

[0009] Moreover, the functional groups on the outer surface of the titanium dioxide shell of the magnetic multi-functional titanium-coated iron amphiphilic particles provided by the present invention have electrostatic and other interactions with the partially hydrolyzed polyacrylamide, which promotes the adsorption of the partially hydrolyzed polyacrylamide on the outer surface of the titanium dioxide shell. At the same time, after adsorption is achieved, due to the wetting effect of the internal structural composition of the amphiphilic particles on the partially hydrolyzed polyacrylamide adsorbed on the outer surface of the titanium dioxide shell, the adsorption process of the partially hydrolyzed polyacrylamide into the titanium dioxide shell is promoted. The polydiethylaminoethyl methacrylate (PDEAEMA) grafted on the inner surface of the titanium dioxide shell and the surface of the core of the magnetic Fe3O4 particles forms a brush-like coating, which increases the specific surface area and enhances the hydrogen bond density. The micropore structure on the titanium dioxide shell provides a channel for the migration and transmission of the partially hydrolyzed polyacrylamide, thereby realizing the adsorption and migration capture of the partially hydrolyzed polyacrylamide by PDEAEMA. The magnetic multi-functional titanium-coated iron amphiphilic particles provided by the present invention greatly improve the adsorption capacity and efficiency of partially hydrolyzed polyacrylamide through the combination of internal and external structures.

[0010] PDEAEMA is also pH-sensitive, exhibiting hydrophilic properties at low pH values ​​and hydrophobic properties at high pH values. This pH sensitivity allows for repeated adsorption and desorption of PDEAEMA from partially hydrolyzed polyacrylamide, making the magnetic multi-functional titanium-coated iron amphiphilic particles reusable and significantly reducing material costs for wastewater treatment. Furthermore, the weak acidity of partially hydrolyzed polyacrylamide facilitates the transfer of PDEAEMA from the outer surface of the titanium dioxide shell to the inner surface of the titanium dioxide shell.

[0011] In addition, the use of a benign solvent for partially hydrolyzed polyacrylamide (such as ethanol) to wash and extract the used magnetic multi-functional titanium-coated iron amphiphilic particles can also remove the adsorbed partially hydrolyzed polyacrylamide, thereby achieving the reuse of the magnetic multi-functional titanium-coated iron amphiphilic particles.

[0012] According to some embodiments of the present invention, the hydrophilic portion is obtained by modifying the outer surface of the titanium dioxide shell with an amino-containing silane coupling agent.

[0013] According to some embodiments of the present invention, the amino-containing silane coupling agent includes 3-aminopropyltriethoxysilane.

[0014] 3-Aminopropyltriethoxysilane modification is used to allow amino groups to exist on the hydrophilic part of the outer surface of the titanium dioxide shell, which can produce weak interactions with partially hydrolyzed polyacrylamide with carboxyl groups, thereby achieving adsorption of partially hydrolyzed polyacrylamide.

[0015] According to some embodiments of the present invention, the hydrophobic portion is obtained by modifying the outer surface of the titanium dioxide shell with an alkyl-containing silane coupling agent.

[0016] According to some embodiments of the present invention, the alkyl-containing silane coupling agent includes n-octyltriethoxysilane.

[0017] According to some embodiments of the present invention, the area of ​​the hydrophilic portion accounts for 1 / 3 to 2 / 3 of the total area of ​​the outer surface of the titanium dioxide shell layer.

[0018] According to some embodiments of the present invention, the particle size of the magnetic multi-functional titanium-coated iron amphiphilic particles is 100 nm<r≤1000 nm.

[0019] In a second aspect, the present invention provides a method for preparing magnetic multi-functional titanium-coated iron amphiphilic particles, comprising:

[0020] S1. Dispersing magnetic Fe3O4 particles and tetrabutyl titanate in an alcohol solvent to obtain titanium-coated iron magnetic particles;

[0021] S2. The titanium-coated iron magnetic particles were dispersed in water, paraffin was added, heated until the paraffin was completely melted, stirred and mixed, cooled and filtered to obtain paraffin balls formed by the titanium-coated iron magnetic particles embedded in the paraffin surface;

[0022] S3. The paraffin balls and the amino-containing silane coupling agent are stirred in dimethyl sulfoxide to react, and then the obtained solid particles are removed from the paraffin to obtain hydrophilic modified particles;

[0023] S4. The hydrophilic modified particles and an alkyl-containing silane coupling agent are stirred in ethanol to react to obtain amphiphilic modified particles;

[0024] S5. The amphiphilic modified particles were mixed with acetic acid for 8-12 h to obtain core-shell separated amphiphilic modified particles;

[0025] S6. The core-shell separated amphiphilic modified particles and 4-(chloromethyl)phenyl trimethoxysilane are subjected to a modification reaction in an alcohol solvent; then a grafting reaction is performed with methacrylic acid diethylaminoethyl ester, and the magnetic multi-functional titanium-coated iron amphiphilic particles are obtained after the reaction is completed.

[0026] The preparation method of the magnetic multi-functional titanium-coated iron amphiphilic particles provided in the present application first uses magnetic Fe3O4 particles as carriers, and realizes hydrolysis of tetra-n-butyl titanate on the surface of the magnetic Fe3O4 particles to form a titanium dioxide shell layer through a sol-gel process. Then, paraffin is used as an oil phase, and the titanium-coated iron magnetic particles are used as a solid particle emulsifier to emulsify the oil and water phases when the temperature is higher than the phase transition temperature of the paraffin, so as to form a stable paraffin-in-water 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 titanium-coated iron magnetic particles are embedded on the surface of the paraffin, and the titanium-coated iron magnetic particles are partially embedded in the paraffin and partially exposed outside the paraffin. Then, the outer surface of the titanium-coated iron magnetic particles exposed outside the paraffin is subjected to hydrophilic modification. Then, the paraffin is removed to expose the part of the titanium-coated iron magnetic particles previously protected by the paraffin, and the outer surface of the part is subjected to hydrophobic modification, so as to obtain amphiphilic particles with a surface including both hydrophilic and hydrophobic parts. Then, acid etching treatment is performed to reduce the size of the magnetic Fe3O4 particles, separate the magnetic Fe3O4 particles from the titanium dioxide shell layer, and form cavities between the core-shell structures. Further, 4-(chloromethyl)phenyl trimethoxysilane is used to modify benzyl chloride 【4-(chloromethyl)phenyl】 on the surface of the magnetic Fe3O4 particles and the inner surface of the titanium dioxide shell layer. The benzyl chloride has high activity, and can be grafted with poly(methacrylic acid diethylaminoethyl ester) (PDEAEMA) through ATRP (atom transfer radical polymerization) reaction to obtain the magnetic multi-functional titanium-coated iron amphiphilic particles.

[0027] In the present application, the titanium dioxide shell layer is used to wrap the magnetic Fe3O4 particles, which can resist corrosion of hydrochloric acid, sulfuric acid, nitric acid or various alkaline reagents for a certain period of time, and ensures the industrial application of the magnetic particles. Moreover, the titanium dioxide shell layer in the present application is a polymer formed by hydrolysis and condensation of tetra-n-butyl titanate. Although the formed titanium dioxide shell layer is relatively dense, there are still intermolecular gaps in the macromolecular framework formed by the condensation reaction in the sol-gel process of the hydrolysis of tetra-n-butyl titanate, which ensures the smooth progress of the subsequent acid etching treatment, 4-(chloromethyl)phenyl trimethoxysilane modification and grafting PDEAEMA process.

[0028] In the present application, the magnetic Fe3O4 particles are reduced in size by acid etching treatment, resulting in core-shell separation, which further causes defects, even micropores or capillaries, in the titanium dioxide shell. These defects, together with the intermolecular space in the titanium dioxide shell, form a micro-porous structure, providing a channel for the transport of partially hydrolyzed polyacrylamide into the interior of the titanium dioxide shell. The acid etching reagent is acetic acid, which can slow down the etching process, ensuring controllable etching process and smoother surface of the inner core of the magnetic Fe3O4 particles. If hydrochloric acid or sulfuric acid is used, it is difficult to control the etching process, which can easily lead to excessive etching, resulting in too weak magnetic properties or even complete loss of magnetic properties of the particles.

[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 (titanium-encased iron magnetic particles), directly leading 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, which is prone to emulsion breaking. 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, which is prone to interface instability and emulsion breaking. Therefore, in order to ensure emulsification and interface stability, the stirring speed in step S2 is preferably controlled in the range of 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 titanium-encased iron magnetic particles using 3-aminopropyl triethoxysilane is carried out in dimethyl sulfoxide, which is realized by a sol-gel composite process on the outer surface of the titanium-encased iron magnetic particles exposed to paraffin, and the amino group is modified on one side of the outer surface of the titanium-encased 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 titanium-coated ferromagnetic particles using n-octyltriethoxysilane is first performed by removing paraffin with an alcohol solvent, so that the titanium-coated ferromagnetic particles are embedded in the paraffin and the protected parts are exposed, and then the exposed parts of the titanium-coated ferromagnetic particles from the embedded paraffin are subjected to the hydrolysis process of n-octyltriethoxysilane to achieve surface sol-gel composite, and n-octyl groups are modified on the other side of the outer surface of the titanium-coated ferromagnetic particles.

[0037] According to some embodiments of the present invention, the mass ratio of the magnetic Fe3O4 particles to tetra-n-butyl titanate is 1:(0.1-1).

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

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

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

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

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

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

[0044] According to some embodiments of the present invention, the particle size of the magnetic Fe3O4 particles is 100 to 500 nm.

[0045] According to some embodiments of the present invention, the particle size ratio of the magnetic Fe3O4 particles to the magnetic Fe3O4 particle core is 100:(10-99).

[0046] 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 titanium shell and the core of the magnetic Fe3O4 particles is too small, which will affect the adsorption capacity of the magnetic multi-effect titanium-iron dual parent 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.

[0047] According to some embodiments of the present application, the grafting reaction comprises: dissolving cuprous chloride and 2,2-bipyridine in a solvent, adding the parent modified particles after the modified reaction treatment and diethylaminoethyl methacrylate, and stirring the reaction under a nitrogen atmosphere and at a temperature of 60-100°C.

[0048] 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).

[0049] According to some embodiments of the present application, the stirring reaction time in step S3 is 5-6h.

[0050] According to some embodiments of the present application, the stirring reaction time in step S4 is 5-6h.

[0051] According to some embodiments of the present application, the dispersing of the magnetic Fe3O4 particles and tetra-n-butyl titanate into the alcohol solvent is performed by ultrasonic and stirring for 12-24h, preferably, the ultrasonic frequency is 60-80Hz and / or the stirring speed is 50-100rpm.

[0052] According to some embodiments of the present application, the dispersing of the titanium-iron magnetic particles into water is performed by ultrasonic and stirring, preferably, the ultrasonic frequency is 60-80Hz and / or the stirring speed is 50-100rpm.

[0053] According to some embodiments of the present application, the dispersing of the paraffin balls into dimethyl sulfoxide is performed by stirring, preferably, the stirring speed is 50-100rpm.

[0054] According to some embodiments of the present application, the dispersing of the hydrophilic modified particles into the alcohol solvent is performed by ultrasonic and stirring, preferably, the ultrasonic frequency is 60-80Hz and / or the stirring speed is 200-300rpm.

[0055] According to some embodiments of the present invention, mixing the amphiphilic modified particles with acetic acid for 8-12 hours comprises: dispersing the amphiphilic modified particles in water, adding acetic acid, and mixing by ultrasound and stirring for 8-12 hours. Preferably, the ultrasound frequency is 60-80 Hz and / or the stirring speed is 50-100 rpm.

[0056] In a third aspect, the present invention provides a magnetic multi-functional titanium-coated iron amphiphilic particle prepared by the preparation method described in the second aspect.

[0057] In a fourth aspect, the present invention provides the use of the magnetic multi-functional titanium-coated iron amphiphilic particles described in the first aspect or the magnetic multi-functional titanium-coated iron amphiphilic particles described in the third aspect in the treatment of oily wastewater containing partially hydrolyzed polyacrylamide.

[0058] The beneficial effects of the present invention are at least:

[0059] (1) The magnetic multi-functional titanium-coated iron amphiphilic particles provided by the present invention have a wide size distribution window, can achieve submicron / micron distribution, and have uniform particle size.

[0060] (2) The magnetic multi-functional titanium-coated iron amphiphilic particles provided by the present invention have excellent emulsification properties. The droplets stabilized by the emulsification using the magnetic multi-functional titanium-coated iron amphiphilic particles can be manipulated by an external magnetic field to achieve the enrichment and migration of oil droplets, thereby achieving oil-water separation. At the same time, they also have selective adsorption characteristics and can selectively adsorb partially hydrolyzed polyacrylamide, and can efficiently treat oily wastewater containing partially hydrolyzed polyacrylamide in one step.

[0061] (3) The magnetic multi-functional titanium-coated iron amphiphilic particles provided by the present invention can realize repeated adsorption and desorption of partially hydrolyzed polyacrylamide, so that the magnetic multi-functional titanium-coated iron amphiphilic particles can be reused many times, and the adsorption capacity for partially hydrolyzed polyacrylamide will not show a significant decrease, which can greatly reduce the material cost of sewage treatment.

[0062] (4) The magnetic multi-functional titanium-coated iron amphiphilic particles provided by the present invention have a structure in which the titanium dioxide shell covers the magnetic Fe3O4 particle core, which can protect the magnetic Fe3O4 particle core and effectively improve the acid and alkali resistance of the amphiphilic particles, so that they can be used to treat sewage with more complex composition.

[0063] (5) The preparation method of the magnetic multi-functional titanium-coated iron amphiphilic particles provided by the present invention has a simple process, low cost and readily available raw materials, and can achieve industrial mass production at the ton level. DETAILED DESCRIPTION

[0064] 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 in detail and do not limit the protection scope of the present application in any way.

[0065] 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.

[0066] Example 1

[0067] S1. 4.0 g of magnetic Fe3O4 particles (particle size of 0.2 μm) were dispersed in 350 mL of ethanol, and 2 g of tetra-n-butyl titanate was added, with additional 80 Hz ultrasonic and 60 rpm overhead stirring, to promote the dispersion of the magnetic Fe3O4 particles by ultrasonic and stirring, for 12 h, to obtain titanium-coated magnetic particles.

[0068] S2. The titanium-coated magnetic particles were dispersed in 400 mL of water, with additional 80 Hz ultrasonic and 60 rpm overhead stirring, to promote the dispersion of the titanium-coated magnetic particles by ultrasonic and stirring. The water temperature was raised to 80℃, and 40 g of paraffin wax (phase transition temperature of 52℃) was added, and 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, and the stirring was continued for 3 min. The stirring and heating were stopped, and the sample was cooled to room temperature, and 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 titanium-coated magnetic particles embedded on the surface of the paraffin wax.

[0069] S3. The paraffin wax ball powder was dispersed in 200 mL of dimethyl sulfoxide, and the dispersion was slowly stirred by an overhead stirrer at a speed of 80 rpm. 40 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 200 mL of ethanol, and the paraffin wax was dissolved, and the solid particles were separated by an external magnetic field, to obtain Fe3O4@TiO2-NH2 particles with amino groups modified on one side of the surface.

[0070] S4. Disperse Fe3O4@TiO2-NH2particles into 200 mL of ethanol, stir the dispersion with an overhead stirrer at 300 rpm with 80 Hz ultrasound. Add 40 mg of n-octylpropyltriethoxysilane to the dispersion and continue stirring for 6 h. Isolate the solid particles using an external magnetic field to obtain C8-Fe3O4@TiO2-NH2particles.

[0071] S5. Disperse C8-Fe3O4@TiO2-NH2particles in 200 mL of water, add 5 mL of acetic acid, stir the dispersion with an overhead stirrer at 60 rpm with 80 Hz ultrasound for 10 h to obtain core-shell separated C8-Fe3O4@TiO2-NH2particles.

[0072] S6. Disperse core-shell separated C8-Fe3O4@TiO2-NH2particles in 200 mL of ethanol, add 20 mg of 4-(chloromethyl)phenyltrimethoxysilane, and stir at 60 rpm for 12 h to obtain modified C8-Fe3O4@TiO2-NH2particles. Dissolve 0.04 g of cuprous chloride and 0.04 g of 2,2-bipyridine in 100 mL of DMF, add the modified C8-Fe3O4@TiO2-NH2particles, and add 0.2 g of DEAEMA, while purging N2to remove oxygen for 30 min, and then heat to 80 °C, and stir at 100 rpm for 3 h. After the reaction is completed, obtain magnetic multi-functional titanium-coated iron amphiphilic particles.

[0073] Example 2

[0074] S1. Disperse 4.0 g of magnetic Fe3O4particles (particle size of 0.2 μm) in 350 mL of ethanol, while adding 4 g of tetra-n-butyl titanate, and add 80 Hz ultrasound and 60 rpm overhead stirring to promote dispersion of the magnetic Fe3O4particles. Continue for 12 h, and then isolate the titanium-coated iron magnetic particles.

[0075] S2. Disperse the titanium-coated iron magnetic particles in 400 mL of water, while adding 80 Hz ultrasound and 60 rpm overhead stirring to promote dispersion of the titanium-coated iron magnetic particles. Increase the water temperature to 80 °C, and add 40 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 1000 rpm for 5 min. Stop stirring and heating, and cool the sample to room temperature, and filter out the solidified paraffin wax balls, and separate them from the water. Disperse the paraffin wax balls on filter paper, and air dry to obtain paraffin wax ball powder with titanium-coated iron magnetic particles embedded on the surface of the paraffin wax.

[0076] S3. Disperse the paraffin ball powder in 200 mL of dimethyl sulfoxide and slowly stir the dispersion at 80 rpm using an overhead stirrer. Add 5 mg of 3-aminopropyltriethoxysilane to the dispersion and continue stirring for 6 hours. Use an external magnetic field to separate the paraffin ball powder from the solvent and allow the paraffin ball powder to dry naturally. Disperse the paraffin ball powder in 200 mL of ethanol, dissolve the paraffin, and separate the solid particles using an external magnetic field to obtain Fe3O4@TiO2-NH2 particles with amino groups modified on one side of the surface.

[0077] S4. Disperse the Fe3O4@TiO2-NH2 particles in 200 mL of ethanol. Stir the dispersion at 300 rpm using an overhead stirrer with 80 Hz ultrasound. Add 5 mg of n-octylpropyltriethoxysilane to the dispersion and continue stirring for 6 hours. Separate the solid particles using an external magnetic field to obtain C8-Fe3O4@TiO2-NH2 particles.

[0078] S5. C8-Fe3O4@TiO2-NH2 particles were dispersed in 200 mL of water, 5 mL of acetic acid was added, and the dispersion was stirred for 10 h using an overhead stirrer at 60 rpm while ultrasonicating at 80 Hz to obtain core-shell separated C8-Fe3O4@TiO2-NH2 particles;

[0079] S6. The core-shell separated C8-Fe3O4@TiO2-NH2 particles were dispersed in 200 mL of ethanol, 30 mg of 4-(chloromethyl)phenyltrimethoxysilane was added, and the mixture was stirred at 60 rpm for 12 h to obtain modified C8-Fe3O4@TiO2-NH2 particles; 0.04 g of cuprous chloride and 0.04 g of 2,2-bipyridine were dissolved in 100 mL of DMF, and the above-mentioned modified C8-Fe3O4@TiO2-NH2 particles were added, and 0.1 g of DEAEMA was added at the same time. N2 was introduced to deoxygenate for 30 min, the temperature was raised to 80 ° C, and the mixture was stirred at 100 rpm for 3 h. After the reaction, magnetic multi-functional titanium-coated iron amphiphilic particles were obtained.

[0080] Example 3

[0081] S1. Disperse 4.0 g of magnetic Fe3O4 particles (particle size of 0.2 μm) in 350 mL of ethanol, add 0.5 g of tetra-n-butyl titanate, apply 80 Hz ultrasound and 60 rpm overhead stirring, maintain ultrasound and stirring to promote the dispersion of magnetic Fe3O4 particles, and continue for 12 hours to separate titanium-coated iron magnetic particles.

[0082] S2. Disperse the titanium-coated iron magnetic particles into 600 mL of water, while adding 80 Hz ultrasound and 60 rpm overhead stirring, keep the ultrasound and stirring to promote the dispersion of the titanium-coated iron magnetic particles. Increase the water temperature to 80 °C, add 100 g of paraffin wax (phase transition temperature of 52 °C), continue stirring until the paraffin wax is completely melted. Turn off the ultrasound and increase the stirring speed to 5000 rpm, continue stirring for 4 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 balls powder with titanium-coated iron magnetic particles embedded on the surface of the paraffin wax.

[0083] S3. Disperse the paraffin wax ball powder into 200 mL of dimethyl sulfoxide, slowly stir the dispersion with an overhead stirrer at a speed of 80 rpm. Add 20 mg of 3- aminopropyltriethoxysilane to the dispersion, continue stirring for 6 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 200 mL of ethanol again, dissolve the paraffin wax, separate the solid particles using an external magnetic field, and obtain Fe3O4@TiO2-NH2 particles with amino groups modified on one side of the surface.

[0084] S4. Disperse the Fe3O4@TiO2-NH2 particles into 200 mL of ethanol, stir the dispersion with an overhead stirrer at a speed of 300 rpm, while adding 80 Hz ultrasound. Add 20 mg of n-octylpropyltriethoxysilane to the dispersion, continue stirring for 6 h. Use an external magnetic field to separate the solid particles, and obtain C8-Fe3O4@TiO2-NH2 particles.

[0085] S5. Disperse the C8-Fe3O4@TiO2-NH2 particles in 200 mL of water, add 5 mL of acetic acid, stir the dispersion with an overhead stirrer at a speed of 60 rpm for 10 h, while adding 80 Hz ultrasound, to obtain C8-Fe3O4@TiO2-NH2 particles with core-shell separation;

[0086] S6. Disperse the C8-Fe3O4@TiO2-NH2 particles with core-shell separation in 200 mL of ethanol, add 10 mg of 4-(chloromethyl)phenyltrimethoxysilane, stir at a speed of 60 rpm for 12 h, to obtain modified C8-Fe3O4@TiO2-NH2 particles; dissolve 0.04 g of cuprous chloride and 0.04 g of 2,2-bipyridine in 100 mL of DMF, add the above modified C8-Fe3O4@TiO2-NH2 particles, add 0.4 g of DEAEMA at the same time, and then deoxygenate for 30 min by passing N2, increase the temperature to 80 °C, and stir at a speed of 100 rpm for 3 h, to obtain magnetic multi-functional titanium-coated iron amphiphilic particles after the reaction is completed.

[0087] Example 4

[0088] S1. Disperse 4.0 g of magnetic Fe3O4 particles (particle size of 0.2 μm) in 350 mL of ethanol, add 2 g of tetra-n-butyl titanate, apply 80 Hz ultrasound and 60 rpm overhead stirring, maintain ultrasound and stirring to promote the dispersion of magnetic Fe3O4 particles, and continue for 12 hours to separate titanium-coated iron magnetic particles.

[0089] S2. Disperse the titanium-coated iron magnetic particles into 400 mL of water, while adding 80 Hz ultrasound and 60 rpm overhead stirring, and maintain ultrasound and stirring to promote the dispersion of the titanium-coated iron magnetic particles. Raise the water temperature to 80 ° C, add 40 g of paraffin wax (phase transition temperature is 52 ° C), and continue stirring until the paraffin wax is completely melted. Turn off the ultrasound and increase the stirring speed to 500 rpm. Because the stirring speed is too low, the particles cannot be delivered to the oil-water interface by mechanical force, the titanium-coated iron magnetic particles cannot be stabilized at the oil-water interface, the oil-water two phases cannot be stably emulsified, the water phase and the oil phase are still two phases, and the paraffin ball powder formed by the titanium-coated iron magnetic particles embedded in the paraffin surface cannot be obtained.

[0090] Example 5

[0091] S1. Disperse 4.0 g of magnetic Fe3O4 particles (particle size of 0.2 μm) in 350 mL of ethanol, add 2 g of tetra-n-butyl titanate, apply 80 Hz ultrasound and 60 rpm overhead stirring, maintain ultrasound and stirring to promote the dispersion of magnetic Fe3O4 particles, and continue for 12 hours to separate titanium-coated iron magnetic particles.

[0092] S2. Disperse the titanium-coated iron magnetic particles into 400mL of water, while adding 80Hz ultrasound and 60rpm overhead stirring, maintaining ultrasound and stirring to promote the dispersion of the titanium-coated iron magnetic particles. Raise the water temperature to 80°C, add 40g paraffin wax (phase transition temperature is 52°C), and continue stirring until the paraffin wax is completely melted. Turn off the ultrasound and increase the stirring speed to 6000rpm. Because the stirring speed is too high, although the titanium-coated iron magnetic particles are mechanically delivered to the oil-water interface for emulsification, the excessively fast mechanical stirring causes the particles to peel off at the interface, making the interface unstable and causing demulsification. It is impossible to obtain paraffin ball powder formed by the titanium-coated iron magnetic particles embedded in the paraffin surface.

[0093] Comparative Example 1

[0094] S1. Disperse 4.0 g of magnetic Fe3O4 particles (particle size of 0.2 μm) in 350 mL of ethanol, add 2 g of tetra-n-butyl titanate, apply 80 Hz ultrasound and 60 rpm overhead stirring, maintain ultrasound and stirring to promote the dispersion of magnetic Fe3O4 particles, and continue for 12 hours to separate titanium-coated iron magnetic particles.

[0095] S2. Disperse the titanium-coated iron magnetic particles into 400mL of water, while adding 80Hz ultrasound and 60rpm overhead stirring, and maintain ultrasound and stirring to promote the dispersion of the titanium-coated iron magnetic particles. Raise the water temperature to 80°C, add 40g of paraffin wax (phase transition temperature is 52°C), and continue stirring until the paraffin wax is completely melted. Turn off the ultrasound and increase the stirring speed to 2000rpm, and continue stirring for 3min. Stop stirring and heating, cool the sample to room temperature, filter out the solidified paraffin balls, and separate them from the water. Spread the paraffin balls on filter paper and dry them naturally to obtain paraffin ball powder formed by the titanium-coated iron magnetic particles embedded in the paraffin surface.

[0096] S3. Disperse the paraffin ball powder in 200 mL of dimethyl sulfoxide and slowly stir the dispersion at 80 rpm using an overhead stirrer. Add 40 mg of 3-aminopropyltriethoxysilane to the dispersion and continue stirring for 6 hours. Use an external magnetic field to separate the paraffin ball powder and the solvent, and let the paraffin ball powder dry naturally. Then disperse the paraffin ball powder in 200 mL of ethanol, dissolve the paraffin, and separate the solid particles using an external magnetic field to obtain Fe3O4@TiO2-NH2 particles with amino groups modified on one side of the surface.

[0097] S4. Disperse the Fe3O4@TiO2-NH2 particles in 200 mL of ethanol. Stir the dispersion at 300 rpm using an overhead stirrer with 80 Hz ultrasound. Add 40 mg of n-octylpropyltriethoxysilane to the dispersion and continue stirring for 6 hours. Separate the solid particles using an external magnetic field to obtain granules.

[0098] Comparative Example 2

[0099] S1. Disperse 4.0 g of magnetic Fe3O4 particles (particle size of 0.2 μm) in 350 mL of ethanol, add 2 g of tetra-n-butyl titanate, apply 80 Hz ultrasound and 60 rpm overhead stirring, maintain ultrasound and stirring to promote the dispersion of magnetic Fe3O4 particles, and continue for 12 hours to separate titanium-coated iron magnetic particles.

[0100] S2. The titanium-coated iron magnetic particles were dispersed in 200 mL of water, 5 mL of acetic acid was added, and the dispersion was stirred for 10 h using an overhead stirrer at 60 rpm while ultrasonically applying 80 Hz to obtain core-shell separated titanium-coated iron magnetic particles;

[0101] S3. The core-shell separated titanium-coated iron magnetic particles were dispersed in 200 mL of ethanol, 20 mg of 4-(chloromethyl)phenyltrimethoxysilane was added, and stirring was carried out at 60 rpm for 12 h to obtain modified titanium-coated iron magnetic particles; 0.04 g of cuprous chloride and 0.04 g of 2,2-bipyridine were dissolved in 100 mL of DMF, the above modified titanium-coated iron magnetic particles were added, 0.2 g of DEAEMA was added, and oxygen was removed by N2 for 30 min, and the temperature was raised to 80°C, and stirring was carried out at 100 rpm for 3 h. The reaction was completed to obtain the particles.

[0102] Comparative Example 3

[0103] 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).

[0104] Comparative Example 4

[0105] 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.

[0106] Performance evaluation

[0107] (I) 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:

[0108] Group Particle size (nm) Example 1 240 Example 2 280 Example 3 210 Comparative Example 1 240 Comparative Example 2 240 Comparative Example 3 240 Comparative Example 4 240

[0109] (II) Wastewater treatment effect

[0110] 1 kg of the particles prepared in each example and comparative example was added to 10 t of oil-containing wastewater containing partially hydrolyzed polyacrylamide (COD value was 2020, oil pollutant content was 52.3 mg / L, and partially hydrolyzed polyacrylamide content was 103.05 mg / L), and the emulsified oil-containing wastewater was obtained by stirring at 1000 rpm for 1 min using a shearing machine; then the migration and enrichment of the magnetic particle emulsified oil droplets were realized by external magnetic field control. The treated wastewater was detected, and the detection method is shown in the following table:

[0111]

[0112] The detection results are shown in the following table:

[0113]

[0114] (III) Recycling performance

[0115] The magnetic multi-effect titanium-encased iron amphiphilic particles of Example 1 were subjected to a regeneration process. The specific method included: collecting the magnetic multi-effect titanium-encased iron amphiphilic particles of Example 1 after wastewater treatment, washing with ethanol, the mass ratio of ethanol to amphiphilic particles being 10:1, and then freeze-drying to obtain regenerated particles.

[0116] The above regenerated particles were used to repeat the process of treating wastewater containing partially hydrolyzed polyacrylamide and oil in (ii), and the indicators of the treated wastewater were similar to the treatment effect of the magnetic multi-effect titanium-encased iron amphiphilic particles of Example 1 in the first wastewater treatment. The recycling number of the magnetic multi-effect titanium-encased iron amphiphilic particles can reach more than 100 times, and the removal effect of COD, oil and partially hydrolyzed polyacrylamide will not be significantly worse.

[0117] It should be noted that the above-described 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 within the scope of the claims, 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 titanium-coated iron amphiphilic particle, characterized in that: The invention comprises a magnetic Fe3O4 particle core and a titanium dioxide shell separated from the magnetic Fe3O4 particle core. The outer surface of the titanium dioxide shell comprises a hydrophilic part and a hydrophobic part. The inner surface of the titanium dioxide shell and the surface of the magnetic Fe3O4 particle core are grafted with polydiethylaminoethyl methacrylate. The titanium dioxide shell has a microporous structure.

2. The magnetic multi-functional titanium-coated iron amphiphilic particles according to claim 1, characterized in that The hydrophilic part is obtained by modifying the outer surface of the titanium dioxide shell with an amino-containing silane coupling agent; And / or, the hydrophobic portion is obtained by modifying the outer surface of the titanium dioxide shell with an alkyl-containing silane coupling agent; And / or, the particle size of the magnetic multi-functional titanium-coated iron amphiphilic particles is 100 nm<r≤1000 nm.

3. The magnetic multi-functional titanium-coated iron amphiphilic particles according to claim 2, characterized in that: The amino-containing silane coupling agent includes 3-aminopropyltriethoxysilane; And / or, the alkyl-containing silane coupling agent includes n-octyltriethoxysilane.

4. A method for preparing magnetic multi-functional titanium-coated iron amphiphilic particles, characterized in that: include: S1. Dispersing magnetic Fe₃O₄ particles and tetra-n-butyl titanate in an alcohol solvent to obtain titanium-coated iron magnetic particles; S2. Disperse the titanium-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 titanium-coated iron magnetic particles embedded in the paraffin wax. S3. Stirring the paraffin wax balls and the amino-containing silane coupling agent in dimethyl sulfoxide to react, and then removing the paraffin wax from the resulting solid particles to obtain hydrophilically modified particles; S4. stirring the hydrophilic modified particles and the alkyl-containing silane coupling agent in ethanol 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. The core-shell separated amphiphilic modified particles are subjected to a modification reaction with 4-(chloromethyl)phenyltrimethoxysilane in an alcohol solvent; and then grafted with diethylaminoethyl methacrylate. After completion of the reaction, the magnetic multi-functional titanium-coated iron amphiphilic particles are obtained.

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 4 or 5, characterized in that The amino-containing silane coupling agent includes 3-aminopropyltriethoxysilane; And / or, the alkyl-containing silane coupling agent includes n-octyltriethoxysilane.

7. The preparation method according to claim 4 or 5, characterized in that The mass ratio of the magnetic Fe3O4 particles to tetrabutyl titanate is 1:(0.1~1); and / or, the mass ratio of the magnetic Fe3O4 particles to 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 4-(chloromethyl)phenyltrimethoxysilane is 1:(0.001-0.01); And / or, the mass ratio of the magnetic Fe3O4 particles to diethylaminoethyl methacrylate is 1:(0.02~0.1).

8. The preparation method according to claim 4 or 5, 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).

9. The preparation method according to claim 4 or 5, 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.

10. A magnetic multi-functional titanium-coated iron amphiphilic particle prepared by the preparation method according to any one of claims 4 to 9.

11. Use of the magnetic multi-functional titanium-coated iron amphiphilic particles according to any one of claims 1 to 3 or the magnetic multi-functional titanium-coated iron amphiphilic particles according to claim 10 in the treatment of oily wastewater containing partially hydrolyzed polyacrylamide.

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