Superparamagnetic ferroferric oxide nanoparticles as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of surfactants, and particularly relates to superparamagnetic ferroferric oxide nanoparticles as well as a preparation method and application thereof. Ferroferric oxide is modified by ethylene polyamine polyether to form the superparamagnetic ferroferric oxide nano-particle with a core-shell structure, the superparamagnetic ferroferric oxide nano-particle comprises an internal core and a shell layer on the outer layer of the core, the shell layer is ethylene polyamine polyether, the core is the superparamagnetic ferroferric oxide nano-particle, and the core and the shell layer are successfully connected through a Si-O bond. The demulsifier prepared from the superparamagnetic ferroferric oxide nanoparticles can realize rapid demulsification of the emulsion under the magnetic response effect at a low temperature, the magnetic particles are small in dosage and can rapidly move to an oil-water interface when the emulsion is demulsified, when an external magnetic field is introduced to the bottom of the emulsion, the magnetic particles are subjected to the magnetic field force effect, the original stress balance state is destroyed, and the demulsification effect of the emulsion is improved. And the magnetic particles move towards the bottom of the container, so that the emulsion is quickly demulsified.

Description

Technical Field

[0001] The invention belongs to the technical field of surfactants, and particularly relates to superparamagnetic ferroferric oxide nanoparticles and a preparation method and application thereof. Background Art

[0002] Demulsification is a key process in the oil production process, which is the process of eliminating the stable conditions of the emulsion, aggregating and stratifying the dispersed droplets. Common demulsification methods include heating, electric field demulsification, ultrasonic method, etc., which belong to physical demulsification methods, that is, physical and mechanical means are used to break the stability of the emulsion; physical demulsification methods are environmentally friendly and do not produce additional waste, but conventional physical demulsification methods represented by high temperature and electro-demulsification have high energy consumption, slow demulsification, and low separation efficiency, and can no longer meet the requirements of economic, energy-saving, and efficient oil production development. The chemical demulsification method is to add a demulsifier to replace the emulsifier molecules in the original emulsion and increase the oil / water interfacial tension to achieve demulsification. It usually does not require additional energy and is faster, but its disadvantage is that it cannot be reused, which increases the difficulty of waste liquid treatment.

[0003] In recent years, in order to improve the recovery rate, the composition of produced fluid has become more complex and the problem of emulsified oil has become increasingly serious. It is urgent to develop environmentally friendly, efficient and low-cost demulsification materials and methods. Therefore, it will greatly improve the demulsification process to find a demulsification material that combines the environmental friendliness of physical demulsification methods and the rapid response of chemical demulsification methods while being reusable. Summary of the invention

[0004] In view of the above problems, in the first aspect, the present invention provides a superparamagnetic ferroferric oxide nanoparticle, wherein the superparamagnetic ferroferric oxide nanoparticle is a core-shell structure, including an inner core and a shell layer outside the core;

[0005] The shell layer is ethylene polyamine polyether, the core is ferrosoferric oxide nanoparticles with superparamagnetism, and the core and the shell layer are connected through Si-O bonds.

[0006] Furthermore, the particle size of the superparamagnetic ferroferric oxide nanoparticles is 300-500 nm, and the saturation magnetization intensity is 75-85 emu / g.

[0007] In a second aspect, the present invention provides a method for preparing superparamagnetic ferroferric oxide nanoparticles, comprising the following steps:

[0008] In a nitrogen atmosphere, ferrosoferric oxide nanoparticles were ultrasonically dispersed in ethanol, toluene was used as solvent, and carboxyl polyethylene glycol triethoxysilane reagent was added to react to obtain black particles with carboxyl groups on the surface.

[0009] Using N-N-dimethylformamide as solvent, polyethylene polyamine polyether and 2-(7-azophenyltriazole-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate are added to the black particles with carboxyl groups on the surface to obtain polyethylene polyamine polyether modified superparamagnetic ferrosoferric oxide nanoparticles.

[0010] Furthermore, the dispersion concentration of the ferrosoferric oxide nanoparticles in ethanol is 1 to 5% by mass;

[0011] The molar ratio of the ferrosoferric oxide nanoparticles to the carboxyl polyethylene glycol triethoxysilane reagent is 1:(1-5), the reaction temperature is 95-135° C., and the reaction time is 7-10 hours.

[0012] Furthermore, the amount of the polyethylene polyamine polyether is 0.01-0.08 mol, the amount of 2-(7-azophenyltriazole-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate is 0.01-0.05 mol, the reaction temperature is 20-40° C., and the reaction time is 1-5 hours.

[0013] In a third aspect, the present invention provides a demulsifier, which is a dispersion formed by dispersing the superparamagnetic ferroferric oxide nanoparticles.

[0014] In a fourth aspect, the present invention provides a demulsification method, which uses the superparamagnetic ferroferric oxide nanoparticles to demulsify, comprising the following steps:

[0015] Ultrasonic dispersion of the superparamagnetic ferroferric oxide nanoparticles in secondary water to form a demulsifier;

[0016] The demulsifier is added into the emulsion and evenly dispersed by shearing, and then an external magnetic field is applied to break the emulsion.

[0017] Furthermore, the emulsion is a single emulsion or an emulsion emulsified with an emulsifier, and the emulsifier is sodium dodecylbenzene sulfonate.

[0018] Furthermore, the emulsification method is: emulsification at a speed of 3000-10000 r / min for 20-90 s on a shear emulsifier; the emulsifier concentration is 300 ppm-700 ppm;

[0019] The concentration of the demulsifier is 0.2-0.4wt%, and the shear dispersion speed when added to the emulsion is 3000-10000r / min, the time is 1min, the demulsification temperature is 25°C, and the external magnetic field during demulsification is a large magnet of 0.2-0.4T.

[0020] The demulsifier can be used in the process of heavy oil production.

[0021] Beneficial effects of the present invention:

[0022] The present invention forms superparamagnetic ferroferric oxide nanoparticles by modifying ferroferric oxide with ethylene polyamine polyether, and successfully realizes rapid demulsification of magnetic responsive emulsion at low temperature. The present invention uses a small amount of magnetic particles during emulsion demulsification, and can quickly move to the oil-water interface. When an external magnetic field is introduced at the bottom of the emulsion, the magnetic particles are acted upon by the magnetic field force, the original force balance state is destroyed, and the magnetic particles move to the bottom of the container, thereby realizing rapid demulsification of the emulsion.

[0023] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 The schematic diagram of the structure of polyethylene polyamine polyether in an embodiment of the present invention is shown;

[0026] Figure 2 The morphology of the magnetic ferroferric oxide particles modified by polyethylene polyamine polyether in the embodiment of the present invention is shown;

[0027] Figure 3 The magnetic properties of the ferroferric oxide magnetic particles modified by polyethylene polyamine polyether in the embodiment of the present invention are shown;

[0028] Figure 4 The emulsion and demulsification effect diagram in the embodiment of the present invention are shown; wherein (a) is the prepared emulsion, (b) is the emulsion after shear dispersion by adding a demulsifier, and (c) is the demulsification effect diagram. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] The invention provides a superparamagnetic ferroferric oxide nanoparticle, which has a core-shell structure and comprises an inner core and a shell layer outside the core, wherein the shell layer is modified with ethylene polyamine polyether, and the core is a ferroferric oxide nanoparticle with superparamagnetism; the core and the shell layer are connected by a Si—O bond.

[0031] The particle size of the superparamagnetic ferroferric oxide nanoparticles is 300-500nm.

[0032] Another object of the present invention is to provide a method for preparing the above-mentioned polyethylene polyamine polyether modified superparamagnetic ferroferric oxide nanoparticles, which specifically comprises the following steps:

[0033] S1: In a nitrogen atmosphere, superparamagnetic FeO4 nanoparticles were ultrasonically dispersed in ethanol, and toluene was used as solvent. Carboxyl polyethylene glycol triethoxysilane reagent was added to react to obtain black particles with carboxyl groups on the surface.

[0034] Wherein, the dispersion concentration of the superparamagnetic ferroferric oxide nanoparticles in ethanol is 1 to 5% by mass;

[0035] The molar ratio of the superparamagnetic ferroferric oxide nanoparticles to the carboxyl polyethylene glycol triethoxysilane reagent is 1:(1-5);

[0036] The reaction temperature of the reaction is 95-135° C., and the reaction time is 7-10 hours.

[0037] S2: Using N-N-dimethylformamide (DMF) as solvent, polyethylene polyamine polyether and 2-(7-azophenyltriazole-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate (HATU) were added to the black particles with carboxyl groups on the surface to obtain polyethylene polyamine polyether modified superparamagnetic iron oxide nanoparticles.

[0038] Wherein, the dosage of the polyethylene polyamine polyether is 0.01-0.08 mol, and the dosage of HATU is 0.01-0.05 mol;

[0039] The reaction temperature of the reaction is 20-40°C and the reaction time is 1-5 hours;

[0040] The synthesis route of polyethylene polyamine polyether is as follows: polyethylene polyamine is used as a starting agent, and propylene oxide, ethylene oxide, propylene oxide and ethylene oxide are respectively subjected to alkoxylation reaction, and the ratio between propylene oxide and ethylene oxide is adjusted to prepare a tetrablock polyether. The obtained molecular structure is as follows Figure 1 shown.

[0041] Another object of the present invention is to provide a magnetic particle demulsifier having good emulsion demulsification ability at a relatively low temperature, which specifically comprises the following steps:

[0042] S1: Preparation of emulsion: The emulsion of the present invention specifically refers to heavy oil with a certain oil-water ratio or heavy oil emulsified with an emulsifier. When treating heavy oil that needs to be emulsified, the emulsifier can be first added to the heavy oil for emulsification to obtain the corresponding emulsion;

[0043] The emulsifier may be sodium dodecylbenzene sulfonate (SDBS), and the concentration of the emulsifier may be 300ppm-700ppm; the emulsifier may be emulsified at a speed of 3000-10000r / min for 20-90s on a shear emulsifier to obtain a SDBS stable emulsion;

[0044] S2: Demulsification of emulsion by magnetic particles: Superparamagnetic ferroferric oxide nanoparticles modified with polyethylene polyamine polyether are ultrasonically dispersed in secondary water to form a demulsifier, and added to the emulsion for uniform shear dispersion. An external magnet is introduced at the bottom of the emulsion for magnetic response demulsification, and the emulsion can be demulsified in a short time; the magnetic particles are superparamagnetic ferroferric oxide nanoparticles.

[0045] In some embodiments, the concentration of the demulsifier is 0.4wt%, and the shear dispersion speed when added to the emulsion is 3000-10000r / min, the time is 1min, the demulsification temperature is 25°C, and the external magnetic field during demulsification is a large magnet of about 0.2-0.4T.

[0046] The present invention is described below by specific examples, but the present invention is not limited thereto, and any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention. The experimental methods used in the following examples are conventional methods unless otherwise specified, and the materials and reagents used can be obtained from commercial channels unless otherwise specified; the quantitative tests in the following examples are repeated three times, and the results are averaged.

[0047] The superparamagnetic ferroferric oxide nanoparticles used in the following examples were purchased from Aladdin Reagents.

[0048] Example 1 Characterization and magnetic properties of superparamagnetic ferroferric oxide nanoparticles modified with polyethylene polyamine polyether.

[0049] 1.1 Synthesis of polyethylene polyamine polyether: Use polyethylene polyamine as the initiator to carry out alkoxylation reaction with propylene oxide, ethylene oxide, propylene oxide and ethylene oxide respectively, adjust the ratio between propylene oxide and ethylene oxide, prepare tetrablock polyether, and obtain a molecular structure as shown below: Figure 1 shown.

[0050] The specific steps include:

[0051] ① 1.37g of polyethylene polyamine was added as an initiator into a high-pressure reactor, and then 0.83g of KOH solid catalyst accounting for 0.5% of the total raw material mass was added;

[0052] ② Seal the reactor system and use dry nitrogen to displace the air in the autoclave, feed kettle and feed pipe;

[0053] ③ Install the heating furnace and start heating and stirring. Use a vacuum pump to evacuate the mixture while heating. Stop evacuating the mixture when the temperature reaches 100°C. Add 65.80g of propylene oxide into the feed kettle, pressurize it to 0.4MPa, open the feed valve and start feeding. Control the reaction temperature at 120-140°C and the pressure at 0.2-0.4MPa. React for 1-3h. After the reaction is completed, age for 1h, cool it to 100°C, and reduce the pressure to normal pressure.

[0054] ④ Add 21.90g of ethylene oxide to the feed kettle and react under the same conditions as step ③. This process may take 1 to 3 hours. After the reaction is completed, age for 1 hour, cool to 100℃, and reduce pressure to normal pressure;

[0055] ⑤ Add 65.80g of propylene oxide into the feed kettle and react under the same conditions as step ③. This process may take 1 to 3 hours. After the reaction is completed, age for 1 hour, cool to 100℃, and reduce pressure to normal pressure;

[0056] ⑥ Add 21.90g of ethylene oxide into the feed kettle and react under the same conditions as step ③ for 1 to 3 hours. After the reaction is completed, the reaction product is neutralized with phosphoric acid to obtain the finished product polyethylene polyamine polyether.

[0057] 1.2 Preparation of superparamagnetic ferroferric oxide magnetic particles modified by polyethylene polyamine polyether, the specific method is as follows:

[0058] In a nitrogen atmosphere, 0.01 mol of Fe3O4 nanoparticles were dispersed in 80 mL of pure ethanol, 200 mL of toluene was used as solvent, 0.02 mol of carboxyl polyethylene glycol triethoxysilane reagent was added and reacted at 110°C for 9 hours to obtain black particles with carboxyl groups on the surface; in other exemplary embodiments, the amount of ethanol used in this step can be 50 mL, 150 mL, 200 mL, etc.; the amount of carboxyl polyethylene glycol triethoxysilane used can be 0.05 mol, 0.03 mol; the reaction temperature can be 95°C, 100°C, 135°C; the reaction time is 7 hours, 10 hours.

[0059] Using DMF as solvent, 0.03 mol of polyethylene polyamine polyether and 0.02 mol of HATU were added to the black particles with carboxyl groups on the surface, and the mixture was reacted at 25° C. for 3 h to obtain polyethylene polyamine polyether-modified superparamagnetic ferroferric oxide nanoparticles. In other exemplary embodiments, the polyethylene polyamine polyether in this step can be 0.01 mol, 0.05 mol or 0.08 mol; the amount of HATU can be 0.01 mol or 0.05 mol.

[0060] Test Example 1

[0061] The morphology of the superparamagnetic ferroferric oxide nanoparticles modified with polyethylene polyamine polyether prepared in Example 1 was characterized. Figure 2 As shown, the superparamagnetic ferroferric oxide magnetic particles modified by polyethylene polyamine polyether have good dispersibility, and the particle size is about 300-500nm.

[0062] Test Example 2

[0063] The magnetic properties of the prepared polyethylene polyamine polyether modified superparamagnetic ferroferric oxide nanoparticles were characterized. Figure 3 As shown, it can be seen that the hysteresis loops of the magnetic particles have no remanence and residual magnetism, indicating that the functionalized ferroferric oxide magnetic particles have superparamagnetism. It can also be seen from the hysteresis loop that the saturation magnetization intensity of the superparamagnetic polyethylene polyamine polyether modified ferroferric oxide magnetic particles is about 80emu / g.

[0064] Example 2 Application of the superparamagnetic ferroferric oxide magnetic particles modified with polyethylene polyamine polyether prepared in Example 1 as a magnetic hyperbranched heavy oil demulsifier.

[0065] The application method is as follows:

[0066] In this embodiment, a stable emulsion containing a fixed oil-water ratio is prepared to simulate the heavy oil in the oil production process. The emulsifier SDBS is dissolved in secondary water, and n-hexane and secondary water dispersed with SDBS are added to a container at an oil-water volume ratio of 2:1. The emulsifier concentration is 350 ppm. The emulsifier is emulsified at a speed of 5000 r / min for 1 min on a shear emulsifier to obtain an SDBS-stabilized emulsion; in other exemplary embodiments, the oil-water volume ratio in this step can be 1:2 or 1:1, wherein the oil phase can be n-decane or n-heptane; the emulsifier concentration can be 500 ppm, 600 ppm or 700 ppm; the emulsifier speed can be 3000 r / min, 6000 r / min or 10000 r / min, and the present invention does not impose specific restrictions on this.

[0067] The magnetic particles of ferroferric oxide modified by polyethylene polyamine polyether are ultrasonically dispersed in secondary water to form a demulsifier, and 1 mL of the demulsifier is added to the emulsion stabilized by SDBS, the demulsifier concentration is 0.4wt%, and the emulsifier is sheared and dispersed at a speed of 5000r / min on a shearing machine for 1min. In other exemplary embodiments, the emulsifier concentration in this step can be 500ppm, 600ppm or 700ppm; the speed of the emulsifier can be 3000r / min, 6000r / min or 10000r / min, and the present invention does not impose specific restrictions on this.

[0068] At room temperature 25°C, place it on a large magnet (0.4T) for magnetic response demulsification, such as Figure 4 As shown, it can be seen that the prepared emulsion has a very good emulsification effect, and the oil and water have completely formed an emulsion. After adding the ferroferric oxide magnetic particle demulsifier modified by polyethylene polyamine polyether and introducing an external magnetic field, the emulsion demulsification effect is very good, achieving complete separation of oil and water. An obvious oil-water interface can be observed, and the demulsification time is 2 minutes.

[0069] In some other exemplary embodiments of the present invention, demulsifying the heavy oil using a demulsifier according to the method in the above-mentioned embodiment 2 (without adding an emulsifier) ​​also has a good oil-water separation effect, and the magnetism of the magnet can also be 0.2T or 0.3T.

[0070] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A superparamagnetic ferroferric oxide nanoparticle, characterized in that: The superparamagnetic ferroferric oxide nanoparticles are of a core-shell structure, including an inner core and a shell layer outside the core; The shell layer is ethylene polyamine polyether, the core is ferrosoferric oxide nanoparticles with superparamagnetism, and the core and the shell layer are connected through Si-O bonds.

2. The superparamagnetic ferroferric oxide nanoparticle according to claim 1, characterized in that: The particle size of the superparamagnetic ferroferric oxide nanoparticles is 300-500nm, and the saturation magnetization intensity is 75-85emu / g.

3. A method for preparing superparamagnetic ferroferric oxide nanoparticles, for preparing the superparamagnetic ferroferric oxide nanoparticles according to claim 1 or 2, characterized in that: The following steps are involved: In a nitrogen atmosphere, ferrosoferric oxide nanoparticles were ultrasonically dispersed in ethanol, toluene was used as solvent, and carboxyl polyethylene glycol triethoxysilane reagent was added to react to obtain black particles with carboxyl groups on the surface. Using N-N-dimethylformamide as solvent, polyethylene polyamine polyether and 2-(7-azophenyltriazole-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate are added to the black particles with carboxyl groups on the surface to obtain polyethylene polyamine polyether modified superparamagnetic ferrosoferric oxide nanoparticles.

4. The method for preparing superparamagnetic ferroferric oxide nanoparticles according to claim 3, characterized in that: The dispersion concentration of the ferrosoferric oxide nanoparticles in ethanol is 1 to 5% by mass; The molar ratio of the ferrosoferric oxide nanoparticles to the carboxyl polyethylene glycol triethoxysilane reagent is 1:(1-5), the reaction temperature is 95-135° C., and the reaction time is 7-10 hours.

5. The method for preparing superparamagnetic ferroferric oxide nanoparticles according to claim 3, characterized in that: The dosage of the polyethylene polyamine polyether is 0.01-0.08 mol, the dosage of 2-(7-azophenyltriazole-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate is 0.01-0.05 mol, the reaction temperature is 20-40° C., and the reaction time is 1-5 hours.

6. A demulsifier, characterized in that: The demulsifier is a dispersion formed by dispersing the superparamagnetic ferroferric oxide nanoparticles according to claim 1 or 2 in secondary water.

7. A demulsification method, characterized in that: Demulsification using the superparamagnetic ferroferric oxide nanoparticles according to claim 1 or 2 is characterized in that it comprises the following steps: Ultrasonic dispersion of the superparamagnetic ferroferric oxide nanoparticles in secondary water to form a demulsifier; The demulsifier is added into the emulsion and evenly dispersed by shearing, and then an external magnetic field is applied to break the emulsion.

8. The demulsification method according to claim 7, characterized in that: The emulsion is a single emulsion or an emulsion emulsified with an emulsifier, and the emulsifier is sodium dodecylbenzene sulfonate.

9. The demulsification method according to claim 7, characterized in that: The concentration of the demulsifier is 0.2-0.4wt%. The shear dispersion speed of the demulsifier added to the emulsion is 3000-10000r / min, the time is 1min, the demulsification temperature is 25°C, and the external magnetic field during demulsification is a large magnet of 0.2-0.4T.

10. Use of the demulsifier according to claim 6 in a heavy oil production process.

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