Composite oil-absorbing resin and preparation method thereof

Abstract

The invention discloses a composite oil-absorbing resin, which comprises the following raw materials: 10-20 mmol of cobalt nitrate, 5-10 mmol of aluminum nitrate, 2-4 g of beta-cyclodextrin, 2.5-5 g of ethylenediaminetetraacetic acid, 0.6-1.25 g of disodium hydrogen phosphate, 0.5-3 g of KH-570, 0.5 wt%-2.5 wt% of polyvinyl alcohol, 10 wt%-90 wt% of octadecyl methacrylate, 10 wt%-90 wt% of isobutyl methacrylate, 0.1 wt%-2 wt% of divinylbenzene, 0.5 wt%-2.5 wt% of benzoyl peroxide and 10 wt%-60 wt% of ethyl acetate; and a preparation method thereof, which specifically comprises the following steps: (1) weighing; (2) preparing cobalt-aluminum bimetallic oxide nanoparticles; (3) grafting beta-cyclodextrin; (4) hydrophobic modification; and (5) preparing the composite oil-absorbing resin. This invention incorporates β-CD cage-like macromolecules into a highly oil-absorbent resin, leveraging the pores formed by the β-CD rings and their hydrophobic pores to achieve a high oil absorption rate. Furthermore, cobalt-aluminum bimetallic oxide nanoparticles contribute to the resin's 3D network structure, enhancing the composite oil-absorbent resin's strength.

Description

Technical Field

[0001] The present invention relates to the technical field of oil-absorbing resins, and more particularly to a composite oil-absorbing resin and a preparation method thereof. Background Art

[0002] Cyclodextrins (CDs), products of starch degradation, are among the most common natural polymers. They are oligosaccharides composed of 6(α), 7(β), or 8(γ)-glucopyranose units linked by α-1,4 glycosidic bonds to form a ring-shaped structure. CD molecules are shaped like a conical torus with a central cavity. The outer surface of CDs is densely covered with hydroxyl groups, making them hydrophilic, while the interior of the cavity is hydrophobic. Therefore, due to their unique structural properties, CDs hold broad application prospects in drug delivery, adsorption, and catalysis.

[0003] β-cyclodextrin (β-CD), a readily available and inexpensive cyclodextrin, inherits the advantages of the aforementioned CDs and can interact with a number of environmental pollutants. The β-CD molecule has seven primary hydroxyl groups located at six positions on the narrow side of the ring and 14 secondary glucopyranose hydroxyl groups located on the broad side. Furthermore, β-CD is a rigid molecule that can enhance the porosity of polymer networks. Consequently, β-CD has attracted attention for the preparation of gels and resins.

[0004] Deng et al. used a one-step method to prepare thermosensitive hydrogels composed of hydroxypropyl-β-CD / glycidyl methacrylate / isopropylacrylamide (Deng JP, He QX, Wu ZL, Yang WT, Journal of Polymer Science Part A: Polymer Chemistry, 2008, 46(6): 2193-2201). The results showed that the introduction of CD groups resulted in higher swelling rates and faster temperature responsiveness in the hydrogels. Furthermore, the CD groups simultaneously played a triple role in these hydrogels: acting as a copolymer, a crosslinking agent, and a pore-forming agent.

[0005] Ding et al. first synthesized a β-CD derivative (β-CD-A) and copolymerized it with octadecyl acrylate (ODA) and BA under the initiation of azobisisobutyronitrile (AIBN) to obtain a cross-linked oil-absorbing resin (Ding L, Li Y, Jia D, Deng JP, Yang WT, Carbohydrate Polymers, 2011, 83(4):1990-1996.). The oil absorption results showed that the oil absorbent containing CD groups has high oil absorption performance. Moreover, β-CD can participate in the polymerization reaction as a comonomer, cross-linking agent, and carrier of CD.

[0006] He et al. successfully prepared highly oil-absorbing microspheres containing β-CD by suspension polymerization (He J, Ding L, Deng JP, Yang WT, Polymers for Advanced Technologies, 2012, 23(4):810-816.). The microspheres not only have a porous structure but also have high oil absorption and excellent oil retention properties.

[0007] However, the existing β-CD derivatives are expensive and the synthesis process of oil-absorbing resins is complicated, making it difficult to produce absorbents on a large scale and to apply them in practice.

[0008] In addition, inorganic nanoparticles can significantly reduce the degree of crosslinking and weaken the entanglement of chains in the polymerization system. Therefore, the advantages of inorganic and organic materials can be combined to improve the performance of polymeric materials. Wang et al. used suspension polymerization to synthesize a biomorphic hollow fiber Al2O3 composite acrylate resin. The composite resin showed a high organic adsorption capacity and good thermal stability (Wang XP, Li QR, Wang YH, Gao LL, Hu XH, XiaoHY, Yan L, Song HR, Polymer Composites, 2018, 39(6): 1988-1993.). Zhang et al. used a method combining bio-template technology and microwave polymerization to synthesize Mn2O3 / poly (St-BMA) resin composite materials and studied their application in oil absorption (Zhang T, Zhang Q, Wang XP, Li QR, Rong J, Qiu FX, RSC Advances, 2015, 5(122): 101186-101192.). The results showed that the resin composite material has good thermal stability and recyclability. Yue et al. prepared a hierarchically porous Al2O3 / acrylate hybrid resin that can effectively reduce mass transfer resistance and accelerate the adsorption of oils and organic solvents (Yue XJ, Zhang T, Yang DY, Qiu FX, Rong J, Xu JC, Fang JS, Chemical Engineering Journal, 2017, 309: 522-531.).

[0009] However, the oil-absorbing resin prepared using inorganic nanoparticles has poor oil absorption performance, especially low adsorption capacity for real oil.

[0010] Therefore, how to develop an oil-absorbing resin with good oil absorption performance and easy preparation is a problem that those skilled in the art urgently need to solve. Summary of the Invention

[0011] In light of this, the present invention aims to provide a composite oil-absorbing resin and a method for preparing the same, addressing the shortcomings of the prior art. This invention employs a novel approach by first grafting a metal oxide onto β-CD to create a more porous structure, followed by modification and compounding. The resulting oil-absorbing resin exhibits excellent oil absorption performance and is simple to prepare.

[0012] In order to achieve the above object, the present invention adopts the following technical solutions:

[0013] A composite oil-absorbing resin comprises the following raw materials in the following amounts: 10-20 mmol of cobalt nitrate, 5-10 mmol of aluminum nitrate, 2-4 g of beta-cyclodextrin (β-CD), 2.5-5 g of ethylenediaminetetraacetic acid (EDTA), 0.6-1.25 g of disodium hydrogen phosphate (Na2HPO4), 0.5-3 g of KH-570, 0.5-2.5 wt% of polyvinyl alcohol (PVA), 10-90 wt% of octadecyl methacrylate (SMA), 10-90 wt% of isobutyl methacrylate, 0.1-2 wt% of divinylbenzene (DVB), 0.5-2.5 wt% of benzoyl peroxide (BPO), and 10-60 wt% of ethyl acetate (EA).

[0014] A method for preparing a composite oil-absorbing resin specifically comprises the following steps:

[0015] (1) Weigh

[0016] Weigh each raw material according to the amount of the composite oil-absorbing resin;

[0017] (2) Preparation of Cobalt-Aluminum Bimetallic Oxide Nanoparticles

[0018] Cobalt nitrate and aluminum nitrate are first dissolved in water, then added to a Na2CO3 solution together with a NaOH solution, and aged at a constant temperature, filtered, dried, ground, and calcined to obtain cobalt-aluminum bimetallic oxide nanoparticles;

[0019] (3) Preparation of β-cyclodextrin grafted cobalt-aluminum bimetallic oxide nanoparticles

[0020] β-cyclodextrin and cobalt-aluminum bimetallic oxide nanoparticles are first dissolved in a NaOH solution, and polyethylene glycol-200 (PEG-200) is added, followed by ultrasonic dispersion and constant temperature stirring. Then, ethylenediaminetetraacetic acid and disodium hydrogen phosphate are added and stirred until a sol-like substance is formed, followed by reaction, washing, and drying to obtain β-cyclodextrin-grafted cobalt-aluminum bimetallic oxide nanoparticles.

[0021] (4) Hydrophobic modification of β-cyclodextrin-grafted cobalt-aluminum bimetallic oxide nanoparticles

[0022] First, β-cyclodextrin-grafted cobalt aluminum bimetallic oxide nanoparticles are dissolved in an ethanol solution and ultrasonically dispersed, and then KH-570 is added, stirred, centrifuged, washed, and dried to obtain hydrophobically modified β-cyclodextrin-grafted cobalt aluminum bimetallic oxide nanoparticles;

[0023] (5) Preparation of composite oil-absorbing resin

[0024] Polyvinyl alcohol is first dissolved in water, swelled at high temperature, and then cooled and nitrogen is passed to remove air. Then, octadecyl methacrylate, isobutyl methacrylate, divinylbenzene, benzoyl peroxide, ethyl acetate and hydrophobically modified β-cyclodextrin grafted cobalt aluminum bimetallic oxide nanoparticles are added. After stirring, a first temperature reaction is performed, and then a second temperature reaction is performed. The mixture is cooled again, washed with deionized water and ethanol in sequence, dried for a first time, purified, and dried for a second time to obtain a composite oil-absorbing resin.

[0025] Furthermore, in the above step (2), the amount of water is 200 mL; the molar concentration of the NaOH solution is 1 mol / L, and the amount used is 80-150 mL; the molar concentration of the Na2CO3 solution is 0.1 mol / L, and the amount used is 100 mL.

[0026] The beneficial effect of adopting the above further technical solution is that by adding NaOH solution, the pH of the system can be kept at about 10 during the preparation process. By adding Na2CO3 solution, due to CO3 - The strong binding ability makes intercalation easier during the preparation of hydrotalcite, which is conducive to the formation of a uniform hydrotalcite structure.

[0027] Furthermore, in the above step (2), the constant temperature aging time is 24 hours; the calcination temperature is 500° C. and the time is 4 hours.

[0028] The beneficial effect of adopting the above further technical solution is that the mixed solution of metal ions is co-precipitated under the action of alkali through constant temperature aging, and a porous structure is formed through calcination, which increases the specific surface area and thus improves the adsorption capacity.

[0029] Furthermore, in the above step (3), the molar concentration of the NaOH solution is 0.01 mol / L, and the amount used is 20 mL; the amount of polyethylene glycol-200 used is 0.5 g.

[0030] The beneficial effect of the above-mentioned further technical solution is that the addition of NaOH solution stabilizes β-CD against alkali and prevents its decomposition in alkaline solutions. The addition of polyethylene glycol-200 as a dispersant increases the solubility of β-CD in water. Ethylenediaminetetraacetic acid serves as a complexing agent. Sodium dihydrogen phosphate serves as a catalyst.

[0031] Furthermore, in the above step (3), the ultrasonic dispersion time is 30 minutes; the constant temperature stirring temperature is 60°C and the time is 1 hour; the reaction temperature is 160°C and the time is 24 hours.

[0032] The beneficial effect of adopting the above-mentioned further technical solution is that ultrasonic dispersion improves the uniformity of the mixture and the stability of the dispersion. Constant temperature stirring accelerates sample dissolution, maintains a uniform temperature, and helps the added sample to evenly enter the reaction liquid, making the reaction process more stable. Through the reaction, a crystalline powder is directly obtained, avoiding the possible formation of hard agglomerates of particles.

[0033] Furthermore, in the above step (4), the volume percentage of the ethanol solution is 50%, and the amount used is 20 to 50 mL.

[0034] The beneficial effect of adopting the above further technical solution is that the hydrolysis rate and efficiency of KH-570 are increased by the ethanol solution, because ethanol can reduce the surface tension of KH-570, making KH-570 more easily hydrolyzed.

[0035] Furthermore, in the above step (4), the stirring temperature is 85° C. and the stirring time is 6 h.

[0036] Furthermore, in the above step (5), the amount of water used is 40 mL.

[0037] Furthermore, in the above step (5), the swelling temperature is 90°C; the mixture is cooled to 40°C; the stirring time is 30 min; the temperature of the first temperature-raising reaction is 75°C, and the time is 2 h; the temperature of the second temperature-raising reaction is 85°C, and the time is 4 h; the mixture is cooled to room temperature again; the temperature of the deionized water is 70°C; the purification time is 24 h; and the temperature of the second drying is 60°C, and the time is 72 h.

[0038] The beneficial effect of adopting the above-mentioned further technical solution is that the polyvinyl alcohol is fully dispersed in water through swelling. The temperature is gradually increased twice to accelerate the reaction. The polymerization reaction is an exothermic reaction. If the temperature is increased in one step, the reaction process will rise too quickly and easily cause the polymerization to form agglomerates, resulting in a large number of by-products.

[0039] It can be seen from the above technical solution that compared with the prior art, the beneficial effects of the present invention are as follows:

[0040] 1. The present invention first grafts β-CD onto cobalt-aluminum bimetallic oxide nanoparticles by a simple hydrothermal method, then modifies the surface of the nanoparticles with KH-570 to make them hydrophobic, and finally composites the nanoparticles with a resin to obtain a composite oil-absorbing resin.

[0041] 2. This invention incorporates β-CD cage-like macromolecules into a highly oil-absorbent resin, leveraging the pores formed by the β-CD rings and their hydrophobic pores to achieve high oil absorption. Furthermore, cobalt-aluminum bimetallic oxide nanoparticles contribute to the resin's 3D network structure, enhancing the composite oil-absorbent resin's strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 Schematic diagram of the synthesis of β-cyclodextrin-grafted cobalt aluminum bimetallic oxide nanoparticles (CoAl-LDO-ECD);

[0043] Figure 2 XRD spectra of CoAl-LDO-ECD before and after hydrophobic modification;

[0044] Figure 3 FT-IR spectra of CoAl-LDO-ECD before hydrophobic modification and CoAl-LDO-ECD-KH and KH-570 after hydrophobic modification;

[0045] Figure 4 The CA diagrams of CoAl-LDO-ECD before and after hydrophobic modification and the high-definition images of the hydrophobicity test are shown;

[0046] Figure 5 The SEM images of CoAl-LDO-ECD and composite oil-absorbing resin;

[0047] Figure 6 The effect of the amount of CoAl-LDO-ECD-KH added to the composite oil-absorbing resin on the saturated oil absorption rate of the tested oil products;

[0048] Figure 7 The regeneration performance of composite oil-absorbing resin in adsorbing chloroform. DETAILED DESCRIPTION

[0049] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only 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 making any creative efforts are within the scope of protection of the present invention.

[0050] Example 1

[0051] A composite oil-absorbing resin comprises the following raw materials: 20 mmol (5.82 g) of Co(NO₃)₂·6H₂O, 10 mmol (3.75 g) of Al(NO₃)₃·9H₂O, 4 g of beta-cyclodextrin, 5 g of ethylenediaminetetraacetic acid, 1.25 g of disodium hydrogen phosphate, 1.58 g of KH-570, 0.8 g of polyvinyl alcohol, 6.4 g of octadecyl methacrylate, 1.6 g of isobutyl methacrylate, 0.8 g of divinylbenzene, 0.8 g of benzoyl peroxide, and 4 g of ethyl acetate;

[0052] The preparation method of the composite oil-absorbing resin specifically comprises the following steps:

[0053] (1) Weigh

[0054] Weigh each raw material according to the amount of the composite oil-absorbing resin;

[0055] (2) Preparation of Cobalt-Aluminum Bimetallic Oxide Nanoparticles

[0056] Co(NO3)2·6H2O and Al(NO3)3·9H2O were first dissolved in 200 mL of water, and then added to 100 mL of Na2CO3 solution with a molar concentration of 0.01 mol / L at the same time as 150 mL of NaOH solution with a molar concentration of 1 mol / L. The mixture was aged at a constant temperature for 24 h to obtain cobalt aluminum double hydroxide (CoAl-LDHs) sol. The sol was then filtered, dried, and ground to obtain cobalt aluminum double hydroxide (CoAl-LDHs) powder. The powder was calcined at 500 °C for 4 h to obtain cobalt aluminum double hydroxide (CoAl-LDO) nanoparticles.

[0057] (3) Preparation of β-cyclodextrin grafted cobalt-aluminum bimetallic oxide nanoparticles

[0058] First, β-cyclodextrin and cobalt aluminum bimetallic oxide (CoAl-LDO) nanoparticles were dissolved in 20 mL of 0.01 mol / L NaOH solution, and 0.5 g of polyethylene glycol-200 was added as a dispersant. Ultrasonic dispersion was performed for 30 min to make them uniformly mixed. Stirring was continued in a constant temperature water bath at 60 ° C for 1 h. Then, ethylenediaminetetraacetic acid and disodium hydrogen phosphate were added. After stirring until a thick sol-like substance was formed, it was quickly poured into a polytetrafluoroethylene reactor and reacted at 160 ° C for 24 h. After washing and drying, β-cyclodextrin grafted cobalt aluminum bimetallic oxide nanoparticles (CoAl-LDO-ECD, the synthesis diagram is shown in FIG. Figure 1 shown);

[0059] (4) Hydrophobic modification of β-cyclodextrin-grafted cobalt-aluminum bimetallic oxide nanoparticles

[0060] β-cyclodextrin grafted cobalt aluminum bimetallic oxide nanoparticles (CoAl-LDO-ECD) were first dissolved in 50 mL of 50% by volume ethanol solution and ultrasonically dispersed. KH-570 was then added and stirred at 85°C for 6 h. The mixture was centrifuged, washed, and dried to obtain hydrophobically modified β-cyclodextrin grafted cobalt aluminum bimetallic oxide nanoparticles (CoAl-LDO-ECD-KH).

[0061] (5) Preparation of composite oil-absorbing resin

[0062] First, polyvinyl alcohol was dissolved in 40 mL of water and fully swelled at 90 ° C. After cooling to 40 ° C, N2 was passed to remove the air. Then, octadecyl methacrylate, isobutyl methacrylate, divinylbenzene, benzoyl peroxide, ethyl acetate and hydrophobically modified β-cyclodextrin grafted cobalt aluminum bimetallic oxide nanoparticles (CoAl-LDO-ECD-KH) were added. After stirring for 30 minutes, the temperature was first raised to 75 ° C for reaction for 2 hours, then raised to 85 ° C for reaction for 4 hours, cooled to room temperature, washed with 70 ° C deionized water and ethanol in sequence, and dried. The dried resin was placed in a Soxhlet extractor for purification for 24 hours, and then placed in a drying oven at 60 ° C for 72 hours to obtain a composite oil-absorbing resin.

[0063] Example 2

[0064] A composite oil-absorbing resin comprises the following raw materials: 10 mmol (2.91 g) of Co(NO₃)₂·6H₂O, 5 mmol (1.875 g) of Al(NO₃)₃·9H₂O, 2 g of beta-cyclodextrin, 2.5 g of ethylenediaminetetraacetic acid, 0.6 g of disodium hydrogen phosphate, 0.5 g of KH-570, 0.8 g of polyvinyl alcohol, 6.4 g of octadecyl methacrylate, 1.6 g of isobutyl methacrylate, 0.8 g of divinylbenzene, 0.8 g of benzoyl peroxide, and 4 g of ethyl acetate;

[0065] The preparation method of the composite oil-absorbing resin specifically comprises the following steps:

[0066] (1) Weigh

[0067] Weigh each raw material according to the amount of the composite oil-absorbing resin;

[0068] (2) Preparation of Cobalt-Aluminum Bimetallic Oxide Nanoparticles

[0069] Co(NO3)2·6H2O and Al(NO3)3·9H2O were first dissolved in 200 mL of water, and then added to 100 mL of 0.01 mol / L Na2CO3 solution simultaneously with 80 mL of 1 mol / L NaOH solution. The mixture was aged at constant temperature for 24 h to obtain cobalt aluminum double hydroxide (CoAl-LDHs) sol. The sol was then filtered, dried, and ground to obtain cobalt aluminum double hydroxide (CoAl-LDHs) powder. The powder was calcined at 500 °C for 4 h to obtain cobalt aluminum double hydroxide (CoAl-LDO) nanoparticles.

[0070] (3) Preparation of β-cyclodextrin grafted cobalt-aluminum bimetallic oxide nanoparticles

[0071] First, β-cyclodextrin and cobalt aluminum bimetallic oxide (CoAl-LDO) nanoparticles were dissolved in 20 mL of 0.01 mol / L NaOH solution, and 0.5 g of polyethylene glycol-200 was added as a dispersant. Ultrasonic dispersion was performed for 30 min to make them uniformly mixed. Stirring was continued in a constant temperature water bath at 60 ° C for 1 h. Then, ethylenediaminetetraacetic acid and disodium hydrogen phosphate were added. After stirring until a thick sol-like substance was formed, it was quickly poured into a polytetrafluoroethylene reactor and reacted at 160 ° C for 24 h. After washing and drying, β-cyclodextrin grafted cobalt aluminum bimetallic oxide nanoparticles (CoAl-LDO-ECD, the synthesis diagram is shown in FIG. Figure 1 shown);

[0072] (4) Hydrophobic modification of β-cyclodextrin-grafted cobalt-aluminum bimetallic oxide nanoparticles

[0073] β-cyclodextrin grafted cobalt aluminum bimetallic oxide nanoparticles (CoAl-LDO-ECD) were first dissolved in 20 mL of 50% by volume ethanol solution and ultrasonically dispersed. KH-570 was then added and stirred at 85°C for 6 h. The mixture was centrifuged, washed, and dried to obtain hydrophobically modified β-cyclodextrin grafted cobalt aluminum bimetallic oxide nanoparticles (CoAl-LDO-ECD-KH).

[0074] (5) Preparation of composite oil-absorbing resin

[0075] First, polyvinyl alcohol was dissolved in 40 mL of water and fully swelled at 90 ° C. After cooling to 40 ° C, N2 was passed to remove the air. Then, octadecyl methacrylate, isobutyl methacrylate, divinylbenzene, benzoyl peroxide, ethyl acetate and hydrophobically modified β-cyclodextrin grafted cobalt aluminum bimetallic oxide nanoparticles (CoAl-LDO-ECD-KH) were added. After stirring for 30 minutes, the temperature was first raised to 75 ° C for reaction for 2 hours, then raised to 85 ° C for reaction for 4 hours, cooled to room temperature, washed with 70 ° C deionized water and ethanol in sequence, and dried. The dried resin was placed in a Soxhlet extractor for purification for 24 hours, and then placed in a drying oven at 60 ° C for 72 hours to obtain a composite oil-absorbing resin.

[0076] Example 3

[0077] A composite oil-absorbing resin comprises the following raw materials: 20 mmol (5.82 g) of Co(NO₃)₂·6H₂O, 10 mmol (3.75 g) of Al(NO₃)₃·9H₂O, 3 g of β-cyclodextrin, 4 g of ethylenediaminetetraacetic acid, 1.0 g of disodium hydrogen phosphate, 3 g of KH-570, 0.8 g of polyvinyl alcohol, 6.4 g of octadecyl methacrylate, 1.6 g of isobutyl methacrylate, 0.8 g of divinylbenzene, 0.8 g of benzoyl peroxide, and 4 g of ethyl acetate;

[0078] The preparation method of the composite oil-absorbing resin specifically comprises the following steps:

[0079] (1) Weigh

[0080] Weigh each raw material according to the amount of the composite oil-absorbing resin;

[0081] (2) Preparation of Cobalt-Aluminum Bimetallic Oxide Nanoparticles

[0082] Co(NO3)2·6H2O and Al(NO3)3·9H2O were first dissolved in 200 mL of water, and then added to 100 mL of 0.01 mol / L Na2CO3 solution along with 100 mL of 1 mol / L NaOH solution. The mixture was then aged at a constant temperature for 24 h to obtain a cobalt aluminum double hydroxide (CoAl-LDHs) sol. The sol was then filtered, dried, and ground to obtain a cobalt aluminum double hydroxide (CoAl-LDHs) powder, which was then calcined at 500°C for 4 h to obtain cobalt aluminum double hydroxide (CoAl-LDO) nanoparticles.

[0083] (3) Preparation of β-cyclodextrin grafted cobalt-aluminum bimetallic oxide nanoparticles

[0084] First, β-cyclodextrin and cobalt aluminum bimetallic oxide (CoAl-LDO) nanoparticles were dissolved in 20 mL of 0.01 mol / L NaOH solution, and 0.5 g of polyethylene glycol-200 was added as a dispersant. Ultrasonic dispersion was performed for 30 min to make them uniformly mixed. Stirring was continued in a constant temperature water bath at 60 ° C for 1 h. Then, ethylenediaminetetraacetic acid and disodium hydrogen phosphate were added. After stirring until a thick sol-like substance was formed, it was quickly poured into a polytetrafluoroethylene reactor and reacted at 160 ° C for 24 h. After washing and drying, β-cyclodextrin grafted cobalt aluminum bimetallic oxide nanoparticles (CoAl-LDO-ECD, the synthesis diagram is shown in FIG. Figure 1 shown);

[0085] (4) Hydrophobic modification of β-cyclodextrin-grafted cobalt-aluminum bimetallic oxide nanoparticles

[0086] β-cyclodextrin grafted cobalt aluminum bimetallic oxide nanoparticles (CoAl-LDO-ECD) were first dissolved in 40 mL of 50% by volume ethanol solution and ultrasonically dispersed. KH-570 was then added and stirred at 85°C for 6 h. The mixture was centrifuged, washed, and dried to obtain hydrophobically modified β-cyclodextrin grafted cobalt aluminum bimetallic oxide nanoparticles (CoAl-LDO-ECD-KH).

[0087] (5) Preparation of composite oil-absorbing resin

[0088] First, polyvinyl alcohol was dissolved in 40 mL of water and fully swelled at 90 ° C. After cooling to 40 ° C, N2 was passed to remove the air. Then, octadecyl methacrylate, isobutyl methacrylate, divinylbenzene, benzoyl peroxide, ethyl acetate and hydrophobically modified β-cyclodextrin grafted cobalt aluminum bimetallic oxide nanoparticles (CoAl-LDO-ECD-KH) were added. After stirring for 30 minutes, the temperature was first raised to 75 ° C for reaction for 2 hours, then raised to 85 ° C for reaction for 4 hours, cooled to room temperature, washed with 70 ° C deionized water and ethanol in sequence, and dried. The dried resin was placed in a Soxhlet extractor for purification for 24 hours, and then placed in a drying oven at 60 ° C for 72 hours to obtain a composite oil-absorbing resin.

[0089] Comparative Example

[0090] The original resin was prepared by the same method as in Example 1 except that the hydrophobically modified β-cyclodextrin-grafted cobalt aluminum bimetallic oxide nanoparticles (CoAl-LDO-ECD-KH) were not present. Specifically,

[0091] First, dissolve polyvinyl alcohol in 40 mL of water and fully swell it at a high temperature of 90 ° C. After cooling to 40 ° C, pass N2 to remove the air, then add octadecyl methacrylate, isobutyl methacrylate, divinylbenzene, benzoyl peroxide and ethyl acetate. After stirring for 30 minutes, first heat it to 75 ° C and react for 2 hours, then heat it to 85 ° C and react for 4 hours, cool it to room temperature, wash it with 70 ° C deionized water and ethanol in turn, and dry it. The dried resin is placed in a Soxhlet extractor for purification for 24 hours, and then placed in a drying oven at 60 ° C for 72 hours to obtain the original resin.

[0092] Performance Testing

[0093] The following performance tests were performed on the composite oil-absorbing resin and its intermediate product in Example 1.

[0094] 1. X-ray diffraction (XRD) characterization

[0095] Figure 2 The XRD patterns of CoAl-LDO-ECD before hydrophobic modification and CoAl-LDO-ECD-KH after hydrophobic modification are shown to study the crystal structures of CoAl-LDO-ECD before hydrophobic modification and CoAl-LDO-ECD-KH after hydrophobic modification.

[0096] Figure 2 The results show that when the peaks appear at 2θ=31.12° and 36.5°, they correspond to the (220) and (311) crystal planes of CoAl2O4 (PDF#38-0814). The diffraction peaks at 2θ=18.07° and 20.66° are attributed to β-CD. The diffraction peak at 2θ=24.06° is attributed to EDTA. These characteristic diffraction peaks indicate that β-CD and EDTA exist in CoAl-LDO-ECD. These characteristic diffraction peaks further confirm that β-CD is successfully grafted on the surface of CoAl-LDO nanoparticles. At the same time, it can also be seen from Figure 2 As can be seen from the figure, the diffraction peaks of CoAl-LDO-ECD before hydrophobic modification and CoAl-LDO-ECD-KH after hydrophobic modification have almost no change, indicating that the crystal structure of CoAl-LDO-ECD will not be changed by the chemical modification of KH-570.

[0097] 2. Fourier transform infrared spectroscopy (FT-IR) characterization

[0098] In order to further understand whether the hydrophobic modification of CoAl-LDO-ECD is successful, FT-IR was used to characterize CoAl-LDO-ECD before and after hydrophobic modification. Figure 3 shown.

[0099] from Figure 3It can be seen that CoAl-LDO-ECD-KH after hydrophobic modification with KH-570 has characteristic absorption peaks of both CoAl-LDO-ECD and KH-570. -1 The absorption peak of CH bond stretching vibration is 1726 cm -1 The absorption peak of C=O bond stretching vibration is 1634 cm -1 The absorption peak of C=C bond stretching vibration is 1455cm -1 The bending vibration absorption peak of -CH2 bond is 1103cm -1 The characteristic absorption peaks of Si-O-Si or Si-O bonds are shown in Figure 2. These characteristic absorption peaks indicate that the organic groups in KH-570 were successfully grafted onto the surface of CoAl-LDO-ECD, indicating that the surface of CoAl-LDO-ECD-KH is hydrophobic.

[0100] 3. Static contact angle (CA) characterization

[0101] In order to test the hydrophobicity of CoAl-LDO-ECD before and after hydrophobic modification, the contact angles of CoAl-LDO-ECD-KH were measured using the static water drop method. The results are shown in Figure 2. Figure 4 shown.

[0102] from Figure 4 It can be seen that the wettability of CoAl-LDO-ECD before hydrophobic modification and CoAl-LDO-ECD-KH after hydrophobic modification to water has obvious difference.

[0103] Figure 4 (a) and (b) show the CA images of CoAl-LDO-ECD before and after hydrophobic modification, respectively. Figure 4 (a) It can be seen that when deionized water drops onto the surface of CoAl-LDO-ECD powder, the water drop collapses in a very short time. The contact angle of CoAl-LDO-ECD is 14.59°, indicating that the surface of CoAl-LDO-ECD is highly hydrophilic. Figure 4 (b) As can be seen, the water droplet is retained on the surface of the CoAl-LDO-ECD-KH powder in a spherical shape with a stable contact angle of 139.95°. The CoAl-LDO-ECD-KH is clearly hydrophobic, indicating that the hydrophobic groups have been successfully grafted onto the surface of the CoAl-LDO-ECD.

[0104] Figure 4(c) and (d) show the high-resolution images of the hydrophobic test of CoAl-LDO-ECD before and after hydrophobic modification, respectively. Figure 4 In (c), when a deionized water droplet is dropped onto the CoAl-LDO-ECD surface, the droplet collapses and spreads completely. Figure 4 The water droplet in (d) remains on the CoAl-LDO-ECD-KH surface as a small ball, and the ball shape does not deform with increasing residence time. This indicates that CoAl-LDO-ECD-KH has good hydrophobicity. This result is consistent with the CA test results, proving that CoAl-LDO-ECD has been successfully hydrophobically modified.

[0105] 4. Scanning electron microscopy (SEM) characterization

[0106] The surface morphology of CoAl-LDO-ECD and composite oil-absorbing resin was characterized by SEM.

[0107] Figure 5 (a) is a SEM image of CoAl-LDO-ECD. As can be observed from the image, the prepared CoAl-LDO-ECD has a flake structure with a diameter of about 500 nm, and the flake structure is uneven in size.

[0108] Figure 5 (b) is a SEM image of the composite oil-absorbing resin. As can be observed from the image, the composite oil-absorbing resin has an uneven surface, with numerous grooves and holes of varying sizes, and the holes vary in depth. These varying depths and grooves increase the pore volume of the composite oil-absorbing resin, expanding its contact area with the oil product and facilitating oil diffusion into the resin. Furthermore, the successful compounding of CoAl-LDO-ECD-KH with the resin indicates that it participates in the construction of the resin's 3D network structure, providing some support for the composite oil-absorbing resin's network structure and increasing its strength. This unique 3D network structure, combining the advantages of CoAl-LDO-ECD-KH particles and acrylic resin, is beneficial for improving the composite oil-absorbing resin's adsorption capacity for oil products.

[0109] 5. Saturated oil absorption rate of composite oil-absorbing resin

[0110] The hydrophobic nature of the CoAl-LDO-ECD-KH nanoparticles allows them to synergize with the original resin in oil absorption. Furthermore, the hydrophobic groups in the CoAl-LDO-ECD-KH nanoparticles can react and crosslink with the polymer chains, contributing to the construction of a 3D network structure and forming more crosslinking points between the CoAl-LDO-ECD-KH and polymer chains. This not only increases the pore structure of the composite oil-absorbing resin but also enhances its gel strength. Therefore, the amount of CoAl-LDO-ECD-KH added influences the oil absorption capacity of the composite oil-absorbing resin.

[0111] The experiment of the saturated oil absorption rate of the composite oil-absorbing resin on the oil to be tested was carried out at room temperature and measured by weighing method. The specific measurement process is as follows: weigh the polyester non-woven bag and 1g of dry oil-absorbing resin, put them into the polyester non-woven bag, and immerse them in the oil or organic solution for saturated oil absorption (12h), and seal them with plastic wrap to prevent the volatilization of the liquid. After the resin absorbs oil, take out the polyester non-woven bag, drip it for a few minutes until there are no residual oil droplets on the surface of the bag, and re-weigh it. Each oil absorption experiment is repeated three times and the average value is taken. The saturated oil absorption rate of the resin can be calculated by formula (1):

[0112]

[0113] In formula (1), Q is the saturated oil absorption rate of the resin, g / g; m0 is the mass of the resin, g; m1 is the mass of the polyester non-woven bag, g; and m2 is the total mass of the resin and the bag after oil absorption, g.

[0114] Effect of the addition amount of CoAl-LDO-ECD-KH on the adsorption of chloroform, toluene, cyclohexane and diesel by the composite oil-absorbing resin Figure 6 shown.

[0115] Depend on Figure 6 As can be seen, with increasing CoAl-LDO-ECD-KH addition, the oil absorption multiple of the composite oil-absorbing resin first increases and then decreases. This trend can be explained by the fact that excessive CoAl-LDO-ECD-KH usage increases the dispersibility of the composite oil-absorbing resin, resulting in smaller resin particles, an imperfect 3D network structure, and reduced network space. Furthermore, CoAl-LDO-ECD-KH occupies the resin's 3D network, reducing its swelling properties, hindering chain extension, and hindering oil absorption. Therefore, when the optimal CoAl-LDO-ECD-KH addition level is 2 wt%, the composite oil-absorbing resin achieves the highest saturated oil absorption rates for diesel, cyclohexane, toluene, and chloroform: 16.17 g / g, 18.62 g / g, 19.92 g / g, and 31.42 g / g, respectively.

[0116] The oil absorption performance of the prepared composite oil-absorbing resin was compared with that of the oil-absorbing resin prepared using inorganic nanoparticles reported in relevant literature in recent years. The results are shown in Table 1.

[0117] Reference 1: Yue XJ, Zhang T, Yang DY, Qiu FX, Rong J, Xu JC, Fang JS, Chemical Engineering Journal, 2017, 309: 522-531.

[0118] Reference 2: Zhang T, Nie XB, Zhang C, Yang DY, Qiu FX, Polymer-Plastics Technology and Engineering, 2018, 57(16): 1665-1675.

[0119] Reference 3: Fang P, Mao PP, Chen J, Du Y, Hou X, Journal of Applied Polymer Science, 2014, 131(8): 631-644.

[0120] Reference 4: Li PX, Yu B, Wei XC, Journal of applied polymer science, 2004, 93(2): 894-900.

[0121] Reference 5: Ma LB, Luo XG, Cai N, Xue YA, Zhu S, FuZ, Yu FQ, Applied SurfaceScience, 2014, 305: 186-193.

[0122] Reference 6: Yan L, Li QR, Wang XP, Song H, Chi HJ, Qiao Y, Zhai Y, Liu D, Polymer-Plastics Technology and Engineering, 2017,56:1857-1865.

[0123] Table 1 Comparison of oil absorption properties of composite oil-absorbing resin and other resins

[0124]

[0125] The results in Table 1 show that the composite oil-absorbing resin prepared in the present invention exhibits relatively better oil absorption performance and a relatively shorter saturated oil absorption time compared to other highly oil-absorbing resins reported in References 1-6. Therefore, the composite oil-absorbing resin prepared in the present invention has promising applications in the adsorption of oils and organic pollutants.

[0126] 6. Regeneration performance of composite oil-absorbing resin

[0127] The reusability of resin is an important characteristic in practical applications. In order to evaluate the reusability of composite oil-absorbing resin, chloroform was used as the adsorbed sample oil, and 8 regeneration performance experiments were carried out on the original resin and the composite oil-absorbing resin.

[0128] The ethanol extraction method is used to achieve the regeneration of the composite oil-absorbing resin. The composite oil-absorbing resin with saturated adsorption of chloroform is selected. The recycling operation process of the composite oil-absorbing resin is as follows: First, the synthesized resin is immersed in chloroform to achieve saturated adsorption; secondly, the resin after saturated adsorption is immersed in a certain amount of ethanol for desorption (multiple times), and the desorption process of the resin is completed by releasing the adsorbed oil; finally, the desorbed resin is placed in an oven for drying. Repeat the oil absorption-deoiling process 8 times to determine the reusability of the resin. For each cycle, the resin must be weighed and recorded before and after oil absorption. The results are as follows Figure 7 shown.

[0129] from Figure 7 It is clearly evident that the chloroform removal efficiency of both the original resin and the composite oil-absorbing resin decreases very slowly with increasing regeneration times. Compared to the original resin, the composite oil-absorbing resin achieved a 57.1% increase in chloroform saturation oil absorption in the first cycle. Furthermore, even after eight adsorption cycles, the composite oil-absorbing resin maintained excellent chloroform adsorption performance. This may be due to the fact that the anhydrous ethanol extraction process does not significantly damage the material structure. Furthermore, it may be due to the numerous crosslinks formed between the hydrophobic groups in the CoAl-LDO-ECD-KH nanoparticles and the polymer chains, contributing to the construction of a 3D network and enhancing the strength of the composite oil-absorbing resin. Even after repeated oil absorption, the chain segments of the composite oil-absorbing resin remain resistant to dissolution. Furthermore, the introduction of β-CD molecules increases the pore structure of the composite oil-absorbing resin. These pores increase the effective volume for oil absorption, providing more oil storage space, accelerating oil absorption and extending the life of the composite oil-absorbing resin.

[0130] The above experiments mainly explored the preparation of CoAl-LDO-ECD-KH and the synthesis of composite oil-absorbing resin, as well as the adsorption performance of the composite oil-absorbing resin on the tested oils. Through the above experiments, the following conclusions were drawn:

[0131] (1) By a simple hydrothermal method, the caged macromolecule β-CD was grafted onto the surface of CoAl-LDO nanoparticles to obtain CoAl-LDO-ECD, which was then modified by KH-570 to make its surface hydrophobic, thus obtaining CoAl-LDO-ECD-KH.

[0132] (2) Characterization results show that the static contact angle of CoAl-LDO-ECD-KH is 139.95°, indicating that it has high hydrophobicity, which is beneficial for the preparation of composite oil-absorbing resin. The addition of CoAl-LDO-ECD-KH improves the thermal stability of the resin. The introduction of β-CD cage-like macromolecules further increases the pore structure of the composite oil-absorbing resin, thereby improving the oil absorption rate and saturated oil absorption rate of the composite oil-absorbing resin.

[0133] (3) By investigating the effect of the amount of CoAl-LDO-ECD-KH added on the saturated oil absorption rate of the tested oil products, it was found that the optimal addition amount of CoAl-LDO-ECD-KH was 2 wt%. Under this condition, the maximum saturated oil absorption rates of the composite oil-absorbing resin for diesel, cyclohexane, toluene, and chloroform were 16.17 g / g, 18.62 g / g, 19.92 g / g, and 31.42 g / g, respectively. Compared with the original resin, the composite oil-absorbing resin had improved saturated oil absorption rates for the tested oil products.

[0134] (4) At the same time, the composite oil-absorbing resin was subjected to eight regeneration experiments to investigate its adsorption of chloroform. The results showed that the composite oil-absorbing resin had good regeneration performance, with its oil absorption rate only slightly decreasing. Compared to the original resin, the composite oil-absorbing resin's saturated oil absorption rate for chloroform increased by 57.1%.

[0135] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present 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 present invention. Therefore, the present invention is not limited to the embodiments shown herein, but is intended to be embodied in the widest possible manner consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a composite oil-absorbing resin, characterized in that: The specific steps include: (1) Weigh Weigh the following raw materials: Co(NO3)2·6H2O 20mmol, Al(NO3)3·9H2O 10mmol, β-cyclodextrin 4g, ethylenediaminetetraacetic acid 5g, disodium hydrogen phosphate 1.25g, KH-570 1.58g, polyvinyl alcohol 0.8g, octadecyl methacrylate 6.4g, isobutyl methacrylate 1.6g, divinylbenzene 0.8g, benzoyl peroxide 0.8g and ethyl acetate 4g; Or, Co(NO3)2·6H2O 10mmol, Al(NO3)3·9H2O 5mmol, β-cyclodextrin 2g, ethylenediaminetetraacetic acid 2.5g, disodium hydrogen phosphate 0.6g, KH-570 0.5g, polyvinyl alcohol 0.8g, octadecyl methacrylate 6.4g, isobutyl methacrylate 1.6g, divinylbenzene 0.8g, benzoyl peroxide 0.8g and ethyl acetate 4g; Or, Co(NO3)2·6H2O 20mmol, Al(NO3)3·9H2O 10mmol, β-cyclodextrin 3g, ethylenediaminetetraacetic acid 4g, disodium hydrogen phosphate 1.0g, KH-570 3g, polyvinyl alcohol 0.8g, octadecyl methacrylate 6.4g, isobutyl methacrylate 1.6g, divinylbenzene 0.8g, benzoyl peroxide 0.8g and ethyl acetate 4g; (2) Preparation of Cobalt-Aluminum Bimetallic Oxide Nanoparticles Cobalt nitrate and aluminum nitrate are first dissolved in water, then added to a Na2CO3 solution together with a NaOH solution, and aged at a constant temperature, filtered, dried, ground, and calcined to obtain cobalt-aluminum bimetallic oxide nanoparticles; (3) Preparation of β-cyclodextrin grafted cobalt-aluminum bimetallic oxide nanoparticles β-cyclodextrin and cobalt-aluminum bimetallic oxide nanoparticles are first dissolved in a NaOH solution, and polyethylene glycol-200 is added, followed by ultrasonic dispersion and constant temperature stirring. Ethylenediaminetetraacetic acid and disodium hydrogen phosphate are then added and stirred until a sol-like substance is formed, followed by reaction, washing, and drying to obtain β-cyclodextrin-grafted cobalt-aluminum bimetallic oxide nanoparticles. (4) Hydrophobic modification of β-cyclodextrin-grafted cobalt-aluminum bimetallic oxide nanoparticles First, β-cyclodextrin-grafted cobalt aluminum bimetallic oxide nanoparticles are dissolved in an ethanol solution and ultrasonically dispersed, and then KH-570 is added, stirred, centrifuged, washed, and dried to obtain hydrophobically modified β-cyclodextrin-grafted cobalt aluminum bimetallic oxide nanoparticles; (5) Preparation of composite oil-absorbing resin Polyvinyl alcohol is first dissolved in water, swelled at high temperature, cooled, and then nitrogen is passed through to remove air. Then, octadecyl methacrylate, isobutyl methacrylate, divinylbenzene, benzoyl peroxide, ethyl acetate, and hydrophobically modified β-cyclodextrin-grafted cobalt aluminum bimetallic oxide nanoparticles are added. After stirring, a first temperature reaction is performed, followed by a second temperature reaction. The mixture is cooled again, washed with deionized water and ethanol in sequence, dried for a first time, purified, and dried for a second time to obtain the composite oil-absorbing resin.

2. The method for preparing a composite oil-absorbing resin according to claim 1, wherein In step (2), the amount of water is 200 mL; the molar concentration of the NaOH solution is 1 mol / L, and the amount is 80-150 mL; the molar concentration of the Na2CO3 solution is 0.1 mol / L, and the amount is 100 mL.

3. The method for preparing a composite oil-absorbing resin according to claim 1, wherein In step (2), the constant temperature aging time is 24 hours; the calcination temperature is 500°C and the time is 4 hours.

4. The method for preparing a composite oil-absorbing resin according to claim 1, wherein In step (3), the molar concentration of the NaOH solution is 0.01 mol / L, and the amount used is 20 mL; the amount of polyethylene glycol-200 used is 0.5 g.

5. The method for preparing a composite oil-absorbing resin according to claim 1, wherein: In step (3), the ultrasonic dispersion time is 30 minutes; the constant temperature stirring temperature is 60°C and the time is 1 hour; the reaction temperature is 160°C and the time is 24 hours.

6. The method for preparing a composite oil-absorbing resin according to claim 1, wherein: In step (4), the volume percentage of the ethanol solution is 50%, and the amount used is 20~50mL.

7. The method for preparing a composite oil-absorbing resin according to claim 1, wherein: In step (4), the stirring temperature is 85° C. and the stirring time is 6 h.

8. The method for preparing a composite oil-absorbing resin according to claim 1, wherein: In step (5), the amount of water used is 40 mL.

9. The method for preparing a composite oil-absorbing resin according to claim 1, wherein: In step (5), the swelling temperature is 90°C; the cooling to 40°C; the stirring time is 30 minutes; the temperature of the first temperature-raising reaction is 75°C, and the time is 2 hours; the temperature of the second temperature-raising reaction is 85°C, and the time is 4 hours; the cooling to room temperature again; the temperature of the deionized water is 70°C; the purification time is 24 hours; the temperature of the second drying is 60°C, and the time is 72 hours.

10. A composite oil-absorbing resin prepared by the preparation method according to claim 1.

Images