Modified alumina nanoparticles and modified composite adsorbents, and preparation method and application thereof

Abstract

This invention discloses a modified alumina nanoparticle and a modified composite adsorbent, as well as their preparation method and application, belonging to the field of polymer adsorbent technology. The modified alumina nanoparticle preparation method is as follows: (1) Alumina nanoparticles are added to a dispersion medium, ultrasonically treated, the supernatant is removed, and more dispersion medium is added; (2) A silane coupling agent is added, the mixture is stirred, washed, and dried to obtain the final product. The modified composite adsorbent includes an oil phase and an aqueous phase; the preparation method is as follows: (1) An oil phase is obtained; (2) A suspension is formed; (3) An aqueous phase is obtained; (4) The oil phase is added to the aqueous phase, stirred, aged, cooled, washed, and dried to obtain the final product. In an acrylate-based polymerization system, this invention introduces modified alumina nanoparticles to chemically modify the material surface, increasing the density of surface active sites and enhancing the specific capture ability of chlorinated organic compounds, thereby achieving rapid capture and selective separation of chlorinated hydrocarbons in the oil phase.

Description

Technical Field

[0001] This invention relates to the field of polymer adsorbent technology, and more specifically to a modified alumina nanoparticle and a modified composite adsorbent, as well as their preparation methods and applications. Background Technology

[0002] With the global reserves of easily exploitable light, low-sulfur crude oil dwindling, the refining industry is facing the increasing challenge of processing heavy, high-impurity crude oil. The high levels of organochlorides in these crude oils are causing increasingly prominent problems such as corrosion of refining and chemical plants, catalyst poisoning, and equipment scaling, becoming key factors restricting the long-term safe operation and economic efficiency of refineries. Developing efficient and economical crude oil dechlorination technologies is not only a necessary requirement to address the trend of deteriorating feedstock quality, but also a strategic measure to promote cleaner and more efficient production in refineries.

[0003] Currently, dechlorination technology mainly revolves around two routes: enhanced electro-desalting process and hydrodechlorination. For example, the invention patent with announcement number CN113862024A discloses "a method for removing organic chlorine from inferior crude oil". This method is based on the efficient demulsification and separation effect of "oil phase + aqueous phase demulsifier" and combined with the chlorine migration and conversion characteristics of chlorine transfer agent. It can remove organic chlorine from inferior crude oil on the basis of the original electro-desalting device. However, it faces limitations such as high energy consumption, insufficient selectivity or harsh operating conditions in actual industrial applications.

[0004] In contrast, adsorption dechlorination technology exhibits unique application prospects due to its operational flexibility, high selectivity, and regeneration potential. Currently, although adsorption dechlorination technology has achieved widespread application, existing adsorption materials generally suffer from bottlenecks such as limited chlorine capacity, insufficient selectivity, and poor regeneration performance.

[0005] Therefore, how to develop a novel adsorbent material that combines high adsorption capacity, excellent selectivity, and good regeneration performance is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to provide modified alumina nanoparticles and modified composite adsorbents, their preparation methods and applications, so as to overcome the shortcomings of the prior art.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A method for preparing modified alumina nanoparticles specifically includes the following steps: (1) Add alumina nanoparticles to a dispersion medium, sonicate, remove the supernatant, and continue to add dispersion medium to obtain alumina nanoparticle suspension; (2) Add the silane coupling agent to the alumina nanoparticle suspension, stir to react, wash and dry to obtain modified alumina nanoparticles.

[0009] In this invention, the modified alumina nanoparticles are the product of hydrophobic modification of hydrophilic Al2O3 nanoparticles by a silane coupling agent.

[0010] Furthermore, in step (1) above, the particle size of the alumina nanoparticles is 200 nm; the dispersion medium is a mixture of ethanol and aqueous solution with a volume ratio of 3:1; the ultrasonic treatment temperature is room temperature, the frequency is 35 kHz, and the time is 1-2 h; the concentration of the alumina nanoparticle suspension is 10 g / L.

[0011] The further beneficial effects of the above-mentioned method are that alumina nanoparticles have good thermal stability and antioxidant properties. The introduction of alumina nanoparticles during the resin synthesis process significantly increases the specific surface area and porous structure of the resin, providing abundant physical adsorption sites.

[0012] Furthermore, in step (2) above, the silane coupling agent is γ-mercaptopropyltriethoxysilane (silane coupling agent KH-580); the amount of silane coupling agent added is 20% of the volume of the alumina nanoparticle suspension.

[0013] The further beneficial effect of the above-mentioned method is that, compared with other silane coupling agents, KH-580 has a unique thiol functional group, which enables the inorganic nanoparticles modified by the silane coupling agent to participate in the acrylate polymerization reaction through strong chemical bonding.

[0014] Furthermore, in step (2) above, the stirring reaction temperature is 45-50℃, the stirring speed is 500r / min, and the time is 4-6h; the washing reagent is anhydrous ethanol, and the washing is performed three times; the drying temperature is 100℃, and the time is 12h.

[0015] The further beneficial effect of the above-mentioned method is that the rotational speed ensures that the alumina nanoparticles can chemically bond with the silane coupling agent in a dispersed and non-aggregated form.

[0016] The present invention also claims protection for a modified alumina nanoparticle prepared by the above preparation method.

[0017] This invention also claims the application of modified alumina nanoparticles prepared by the above method in the targeted adsorption of chlorinated hydrocarbons in an oil phase. The chlorinated hydrocarbons are organochlorinated compounds such as chloroform, isobutane, and 2-chloropropane.

[0018] A modified composite adsorbent, the raw materials of which include an oil phase and an aqueous phase; The oil phase comprises the following raw materials in parts by weight: 1-3 parts butyl methacrylate, 8-10 parts hexadecyl methacrylate, 1-3 parts diallyl phthalate, and 0.5-1.0 parts crosslinking agent; The aqueous phase comprises the following raw materials in parts by weight: 0.5-1.5 parts of modified alumina nanoparticles prepared by any one of claims 1-3, 0.5-1.0 parts of initiator, 0.1-1.0 parts of dispersant, and 30-80 parts of water.

[0019] Furthermore, the crosslinking agent mentioned above is N,N-dimethylbisacrylamide.

[0020] Furthermore, the initiator mentioned above is benzoyl peroxide.

[0021] Furthermore, the dispersant mentioned above is polyvinyl alcohol.

[0022] The further beneficial effect of the above-mentioned method is that polyvinyl alcohol is an amphiphilic surfactant with a large number of hydroxyl groups in its molecules, possessing high hydrophilicity, strong adhesion, and good chemical modifiability. When added to the synthesis system, under mechanical stirring, the oil phase is stably dispersed in the aqueous phase as spherical droplets, allowing polymerization to occur.

[0023] A method for preparing the above-mentioned modified composite adsorbent specifically includes the following steps: (1) Mix butyl methacrylate, hexadecyl methacrylate, diallyl phthalate, modified alumina nanoparticles and crosslinking agent evenly to obtain an oil phase for later use; (2) Add the modified alumina nanoparticles to water and sonicate to form a uniform and stable suspension; (3) Add the initiator and dispersant to the suspension, stir to dissolve, and obtain the aqueous phase; (4) Add the oil phase to the aqueous phase, stir to react, age, cool, wash and dry to obtain the modified composite adsorbent.

[0024] Furthermore, in step (2) above, the temperature of the ultrasonic treatment is 40℃ and the frequency is 35kHz.

[0025] Furthermore, in step (3) above, the temperature for stirring and dissolving is 60°C.

[0026] Furthermore, in step (4) above, the stirring reaction temperature is 75-80℃, the stirring speed is 200r / min, and the time is 6-8h; the aging temperature is 80-90℃, and the time is 0.5-1h; the washing reagents are anhydrous ethanol and deionized water; the drying temperature is 55-65℃, until constant weight.

[0027] This invention also claims protection for the application of the above-described modified composite adsorbent or the modified composite adsorbent prepared by the above-described method in the targeted adsorption of chlorinated hydrocarbons in an oil phase. In this context, the chlorinated hydrocarbons are organochlorinated compounds such as chloroform, isobutane, and 2-chloropropane.

[0028] As can be seen from the above technical solution, compared with the prior art, the beneficial effects of the present invention are as follows: 1. In the acrylate-based polymerization system, the present invention introduces modified alumina nanoparticles to chemically modify the surface of the material, increase the density of surface active sites, and enhance the specific capture ability of chlorinated organic compounds, thereby achieving rapid capture and selective separation of chlorinated hydrocarbons in the oil phase.

[0029] 2. This invention introduces inorganic modified alumina nanoparticles into an acrylate-based polymerization system, successfully constructing a modified functional material with an organic-inorganic hybrid structure. The modified alumina nanoparticles can enhance the surface active site density of the modified composite adsorbent and optimize its hydrophilic and hydrophobic properties, thereby enabling the modified composite adsorbent to efficiently and effectively adsorb chlorinated hydrocarbon pollutants in condensate oil.

[0030] 3. The modified composite adsorbent of this invention significantly increases the specific surface area and porous structure of the resin, providing abundant physical adsorption sites; in addition, the ternary network structure generates specific interactions with chlorinated organic compounds through polar interactions. Attached Figure Description

[0031] Figure 1 Electron micrographs of the unmodified composite adsorbent of Comparative Example 1 and the modified composite adsorbent of Example 2 are shown. The left image is a surface morphology of the unmodified composite adsorbent of Comparative Example 1, and the right image is a surface morphology of the modified composite adsorbent of Example 2. Figure 2 The images are scanning electron microscope (SEM) images of the unmodified composite adsorbent of Comparative Example 1 and the modified composite adsorbent of Example 2. Among them, (a), (a1), and (a2) are surface morphology images of the unmodified composite adsorbent of Comparative Example 1, and (b), (b1), and (b2) are surface morphology images of the modified composite adsorbent of Example 2. Detailed Implementation

[0032] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Example 1 The preparation method of modified alumina nanoparticles specifically includes the following steps: (1) Add 5g of alumina nanoparticles with a particle size of 200nm to a mixture of anhydrous ethanol-water solution with a volume ratio of 3:1, and sonicate at room temperature and 35kHz for 1h to remove excess impurities on the surface of the alumina nanoparticles. After sonication, remove the supernatant and continue to add a mixture of anhydrous ethanol-water solution with a volume ratio of 3:1 to 500mL to obtain an alumina nanoparticle suspension. (3) Add 20 mL of γ-mercaptopropyltriethoxysilane to the alumina nanoparticle suspension and react for 5 h under constant temperature and sealed conditions with strong stirring at 500 r / min. After cooling, the solid and liquid are separated. The obtained solid particles are washed three times with anhydrous ethanol and dried at 100 °C for 12 h to obtain modified alumina nanoparticles.

[0034] Example 2 The modified composite adsorbent comprises an oil phase and an aqueous phase. The oil phase consists of 1.43 g butyl methacrylate, 7.14 g hexadecyl methacrylate, 1.43 g diallyl phthalate, and 0.07 g N,N-methylenebisacrylamide. The aqueous phase consists of 0.8 g modified alumina nanoparticles obtained in Example 1, 0.13 g polyvinyl alcohol, 0.10 g benzoyl peroxide, and 40 mL deionized water. The preparation method of the above-mentioned modified composite adsorbent specifically includes the following steps: (1) Mix butyl methacrylate, hexadecyl methacrylate, dipropylene phthalate and N,N-methylenebisacrylamide evenly to obtain an oil phase for later use; (2) Deionized water and modified alumina nanoparticles were precisely added to a three-necked flask, the temperature was raised to 40°C, and ultrasonic treatment was performed at 35 kHz to form a uniform and stable suspension. (3) Add polyvinyl alcohol and benzoyl peroxide to the suspension, heat to 60°C and stir to dissolve, to obtain an aqueous phase; (4) Add the oil phase to the aqueous phase, heat to 75°C, and react for 7 hours under mechanical stirring at 200 r / min to form uniform droplets in the water. Then age at 90°C for 1 hour. After the product cools to room temperature, wash with anhydrous ethanol and deionized water, and vacuum dry in an oven at 45°C to constant weight to obtain the modified composite adsorbent.

[0035] Example 3 The modified composite adsorbent comprises an oil phase and an aqueous phase. The oil phase consists of 1.48 g of butyl methacrylate, 7.41 g of hexadecyl methacrylate, 1.11 g of diallyl phthalate, and 0.05 g of N,N-methylenebisacrylamide. The aqueous phase consists of 1.0 g of modified alumina nanoparticles prepared in Example 1, 0.10 g of polyvinyl alcohol, 0.13 g of benzoyl peroxide, and 50 mL of deionized water. The preparation method of the above-mentioned modified composite adsorbent specifically includes the following steps: (1) Mix butyl methacrylate, hexadecyl methacrylate, dipropylene phthalate and N,N-methylenebisacrylamide evenly to obtain an oil phase for later use; (2) Deionized water and modified alumina nanoparticles were precisely added to a three-necked flask, the temperature was raised to 40°C, and ultrasonic treatment was performed at 35 kHz to form a uniform and stable suspension. (3) Add polyvinyl alcohol and benzoyl peroxide to the suspension, heat to 60°C and stir to dissolve, to obtain an aqueous phase; (4) Add the oil phase to the aqueous phase, heat to 75°C, and react for 7 hours under mechanical stirring at 200 r / min to form uniform droplets in the water. Then age at 90°C for 1 hour. After the product cools to room temperature, wash with anhydrous ethanol and deionized water, and vacuum dry in an oven at 45°C to constant weight to obtain the composite adsorbent.

[0036] Comparative Example 1 The unmodified composite adsorbent (different from Example 2 only in that it does not contain modified alumina nanoparticles) consists of an oil phase and an aqueous phase. The oil phase comprises 1.43 g of butyl methacrylate, 7.14 g of hexadecyl methacrylate, 1.43 g of diallyl phthalate, and 0.07 g of N,N-methylenebisacrylamide. The aqueous phase comprises 0.13 g of polyvinyl alcohol, 0.10 g of benzoyl peroxide, and 40 mL of deionized water. The preparation method of the above-mentioned unmodified composite adsorbent specifically includes the following steps: (1) Mix butyl methacrylate, hexadecyl methacrylate, dipropylene phthalate and N,N-methylenebisacrylamide evenly to obtain an oil phase for later use; (2) Add deionized water, polyvinyl alcohol and benzoyl peroxide precisely to a beaker, heat to 60°C and stir to dissolve, to obtain an aqueous phase; (3) Add the oil phase to the aqueous phase, heat to 75°C, and react for 7 hours under mechanical stirring at 200 r / min to form uniform droplets in the water. Then age at 90°C for 1 hour. After the product cools to room temperature, wash with anhydrous ethanol and deionized water, and vacuum dry in an oven at 45°C to constant weight to obtain the unmodified composite adsorbent.

[0037] Performance testing 1. Characterization Electron micrographs and scanning electron micrographs of the unmodified composite adsorbent in Comparative Example 1 and the modified composite adsorbent in Example 2 are shown below. Figure 1 and Figure 2 As shown.

[0038] Depend on Figure 1 and Figure 2 As can be seen, compared with the unmodified composite adsorbent of Comparative Example 1, the modified composite adsorbent of Example 2 has a rich variety and a large number of pores and a well-preserved, interconnected, high-density pore structure. Furthermore, the material surface is coated with significant fine modified alumina nanoparticles. As an inorganic modifying component, the modified alumina nanoparticles not only act as pore-forming agents, influencing the crosslinking and phase separation processes of the polymer network and reshaping the resin's pore structure, but the nanoparticles themselves also directly adhere to the pore surface, constituting the observed particulate matter. While providing numerous adsorption sites for organochlorine compounds, they also construct an efficient mass transport pathway, thus laying a solid structural foundation for an efficient adsorption process.

[0039] 2. Simulated oil phase adsorption A simulated oil phase (concentration 50 mg / g) containing organochlorinated compounds such as chloroform, isochlorobutane, and 2-chloropropane was prepared using dodecane as a solvent. 0.25 g each of the unmodified composite adsorbent prepared in Comparative Example 1 and the modified composite adsorbent prepared in Examples 2-3 were added to 10 mL of the simulated oil phase and adsorbed at 35 °C for 80 min. The chlorine content after adsorption was determined by GC-FID, and the removal rate was calculated. At the same time, the time for the sample to reach saturation adsorption of chloroform and the removal rate of chloroform after 5 adsorption-desorption cycles were investigated.

[0040] The results are shown in Table 1.

[0041] Table 1 Removal rate, saturation adsorption time, and cyclic adsorption performance of each sample

[0042] As shown in Table 1, the unmodified composite adsorbent in Comparative Example 1 achieved a removal rate of 76.32% for chloroform, reaching saturation adsorption within 60 minutes; the removal rates for chloroisobutane and 2-chloropropane were 75.33% and 43.85%, respectively; after 5 adsorption-desorption cycles, the removal rate for chloroform was 57.93%.

[0043] Example 2 shows that the modified composite adsorbent achieved a removal rate of 84.56% for chloroform, reaching saturation adsorption within 80 minutes; the removal rates for chloroisobutane and 2-chloropropane reached 83.21% and 54.23%, respectively. After 5 adsorption-desorption cycles, the removal rate for chloroform remained at 68.3%.

[0044] Example 3 shows that the modified composite adsorbent achieved a removal rate of 82.49% for chloroform, reaching saturation adsorption within 80 minutes; the removal rates for chloroisobutane and 2-chloropropane reached 80.53% and 58.21%, respectively. After 5 adsorption-desorption cycles, the removal rate for chloroform remained at 61.3%.

[0045] 3. Adsorption of actual oil samples Crude oil (condensate oil containing chlorinated hydrocarbons) produced from Pengshen 10 well in the Chuanzhong Oil and Gas Field of PetroChina Southwest Oil and Gas Field was selected as the actual oil sample. 0.25g of the unmodified composite adsorbent prepared in Comparative Example 1 and the modified composite adsorbent prepared in Examples 2-3 were added to 10mL of the experimental oil sample respectively. The adsorption was carried out at 35℃ for 80min. The chlorine content after adsorption was determined by GC-FID and the removal rate was calculated. At the same time, the time for the sample to reach saturation adsorption of chlorinated hydrocarbons was investigated.

[0046] The results are shown in Table 2.

[0047] Table 2 Removal rate and saturation adsorption time for each sample

[0048] As shown in Table 2, the unmodified composite adsorbent in Comparative Example 1 achieved a removal rate of 64.18% for chlorinated hydrocarbons in the oil sample, reaching saturation adsorption within 60 minutes; the modified composite adsorbent in Example 2 achieved a removal rate of 73.19% for chlorinated hydrocarbons in the oil sample, reaching saturation adsorption within 80 minutes; and the modified composite adsorbent in Example 3 achieved a removal rate of 70.56% for chlorinated hydrocarbons in the oil sample, reaching saturation adsorption within 80 minutes.

[0049] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing modified alumina nanoparticles, characterized in that, Specifically, the following steps are included: (1) Add alumina nanoparticles to a dispersion medium, sonicate, remove the supernatant, and continue to add dispersion medium to obtain alumina nanoparticle suspension; (2) Add the silane coupling agent to the alumina nanoparticle suspension, stir to react, wash and dry to obtain the modified alumina nanoparticles.

2. The method for preparing modified alumina nanoparticles according to claim 1, characterized in that, In step (1), the alumina nanoparticles have a particle size of 200 nm; the dispersion medium is a mixture of ethanol and aqueous solution with a volume ratio of 3:1; the ultrasonic treatment is performed at room temperature, at a frequency of 35 kHz, and for 1-2 hours; and the concentration of the alumina nanoparticle suspension is 10 g / L.

3. The method for preparing modified alumina nanoparticles according to claim 1, characterized in that, In step (2), the silane coupling agent is γ-mercaptopropyltriethoxysilane; the amount of silane coupling agent added is 20% of the volume of the alumina nanoparticle suspension; the stirring reaction temperature is 45-50℃, the stirring speed is 500r / min, and the time is 4-6h; the washing reagent is anhydrous ethanol, and the washing is performed three times; the drying temperature is 100℃, and the drying time is 12h.

4. Modified alumina nanoparticles prepared by the preparation method according to any one of claims 1-3.

5. The application of modified alumina nanoparticles prepared by the preparation method according to any one of claims 1-3 in the targeted adsorption of chlorinated hydrocarbons in an oil phase.

6. A modified composite adsorbent, characterized in that, The raw materials include an oil phase and an aqueous phase; The oil phase comprises the following raw materials in parts by weight: 1-3 parts butyl methacrylate, 8-10 parts hexadecyl methacrylate, 1-3 parts diallyl phthalate, and 0.5-1.0 parts crosslinking agent; The aqueous phase comprises the following raw materials in parts by weight: 0.5-1.5 parts of modified alumina nanoparticles prepared by the preparation method according to any one of claims 1-3, 0.5-1.0 parts of initiator, 0.1-1.0 parts of dispersant, and 30-80 parts of water.

7. The modified composite adsorbent according to claim 6, characterized in that, The crosslinking agent is N,N-dimethylbisacrylamide; the initiator is benzoyl peroxide; and the dispersant is polyvinyl alcohol.

8. A method for preparing the modified composite adsorbent as described in claim 6 or 7, characterized in that, Specifically, the following steps are included: (1) Mix butyl methacrylate, hexadecyl methacrylate, diallyl phthalate, modified alumina nanoparticles and crosslinking agent evenly to obtain an oil phase for later use; (2) Add the modified alumina nanoparticles to water and sonicate them to form a uniform and stable suspension; (3) Add the initiator and dispersant to the suspension, stir to dissolve, and obtain the aqueous phase; (4) Add the oil phase to the aqueous phase, stir to react, age, cool, wash and dry to obtain the modified composite adsorbent.

9. The method for preparing a modified composite adsorbent according to claim 8, characterized in that, In step (2), the temperature of the ultrasonic treatment is 40°C and the frequency is 35kHz; In step (3), the temperature for stirring and dissolving is 60°C; In step (4), the stirring reaction is carried out at a temperature of 75-80℃, a rotation speed of 200r / min, and a time of 6-8h; the aging temperature is 80-90℃ and the time is 0.5-1h; the washing reagents are anhydrous ethanol and deionized water; the drying temperature is 55-65℃ until constant weight is achieved.

10. The application of a modified composite adsorbent as described in claim 6 or 7, or a modified composite adsorbent prepared by the preparation method as described in claim 8 or 9, in the targeted adsorption of chlorinated hydrocarbons in an oil phase.

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