Hydrophobic oleophylic magnetic fluff for oil-water separation and preparation method of hydrophobic oleophylic magnetic fluff

Abstract

The invention relates to the field of magnetic villus, in particular to hydrophobic oleophylic magnetic villus for oil-water separation and a preparation method thereof, and aims to solve the problems of difficulty in recovery, poor wear resistance, difficulty in reuse and the like due to poor waterproof and antifouling effects and no magnetic responsiveness. The preparation method comprises the following steps: pretreating a base material through washing, drying and opening, then adsorbing polyvinylpyrrolidone on the surfaces of ferroferric oxide nano particles through a steric hindrance effect, contacting ferroferric oxide-polyvinylpyrrolidone colloid with pretreated hard waste, contacting a compound modification liquid with magnetic fluff, purifying and curing to obtain the magnetic fluff composite material. And finally obtaining hydrophobic oleophylic magnetic fluff. The four functions of hydrophobicity, lipophilicity, magnetism and wear resistance are synergistically endowed to the cashmere / wool hard waste base material, and finally the magnetic fluff with the efficient oil-water separation capacity and the convenient magnetic field recovery characteristic is formed.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of magnetic fluff, and particularly relates to a hydrophobic and oleophilic magnetic fluff for oil-water separation and a preparation method thereof. BACKGROUND

[0002] With the development of industry and the increase of marine transportation activities, the problem of water pollution caused by oil pollutant leakage is becoming increasingly serious, and the research and development of efficient oil-water separation materials has become a research hotspot in the field of environmental protection. Existing oil-water separation materials mainly include inorganic membranes, organic polymer materials, porous composite materials, etc., but generally have defects such as high cost, difficulty in recycling after separation, insufficient mechanical wear resistance, and easy clogging by oil stains. At the same time, a large amount of back silk (short fluff offcut) is generated in the spinning process of cashmere and wool in the textile industry. This kind of back silk is short in length and has disordered fibers, and it is difficult to be directly used for spinning reprocessing, and is usually incinerated or landfilled, which not only causes resource waste, but also pollutes the environment. If this kind of waste back silk can be converted into high-performance oil-water separation materials, it can not only solve the problem of back silk recycling, but also reduce the production cost of oil-water separation materials, which conforms to the development trend of resource recycling and green environmental protection. At present, some oil-water separation materials based on natural fibers have been developed, but most of them have problems such as poor water and stain resistance, difficulty in recycling due to no magnetic response, poor wear resistance and difficulty in repeated use, which limits their practical application. Therefore, it is of great practical significance to develop an oil-water separation material using cashmere / wool back silk as raw material, which has hydrophobic and oleophilic, magnetic recycling, wear-resistant and stain-resistant properties. SUMMARY

[0003] In order to overcome the above technical problems, the purpose of the present application is to provide a hydrophobic and oleophilic magnetic fluff for oil-water separation and a preparation method thereof.

[0004] The purpose of the present application can be achieved by the following technical solutions:

[0005] In a first aspect, the present application provides a hydrophobic and oleophilic magnetic fluff for oil-water separation, comprising the following components by weight:

[0006] 12-15 parts of a substrate, 1-2 parts of ferroferric oxide magnetic particles, 250-300 parts of distilled water, 0.01-0.03 parts of polyvinylpyrrolidone, and 200-220 parts of a compounded modification liquid;

[0007] The compounded modification liquid is prepared by the following steps:

[0008] Step a1: Trifluoropropylmethylcyclotrisiloxane was added to an industrial-grade 316L stainless steel reactor. The system was evacuated and purged with nitrogen using a vacuum unit and a nitrogen buffer tank. This process was repeated three times. Then, anhydrous tetrahydrofuran was added to the reactor using a metering pump. The reactor jacket was circulated with chilled brine to stabilize the system temperature at 0-5℃. A n-butyllithium-n-hexane solution was added, and the reaction was carried out for 2-2.2 hours. Dimethylchlorosilane was added, and the reaction was carried out at room temperature for 12-13 hours. Then, n-hexane was added and stirred. The mixture was transferred to a stainless steel separatory tank and washed with deionized water 3-4 times. Anhydrous sodium sulfate was added, and the mixture was allowed to stand and dry for 4-4.2 hours. The precipitate was removed by filtration. The mixture was then distilled under reduced pressure at 80-90℃ to obtain a hydrogen-containing silane.

[0009] Step a2: Anhydrous toluene, vinyltrimethoxysilane, and platinum (O)-1,3-diethylene-1,1,3,3-tetramethyldisiloxane were added to an industrial-grade 316L stainless steel reactor. Nitrogen gas was introduced for protection. The mixture was stirred for 20-30 minutes at a temperature of 25-30℃ and a stirring rate of 300-350 r / min. The temperature was then raised to 80-85℃, and hydrogen-containing silane was added dropwise over a period of 4 hours. After the addition was complete, the reaction continued for 20-22 hours. The mixture was then distilled under reduced pressure at a temperature of 100-110℃ to obtain fluorinated silane.

[0010] Step a3: Add anhydrous ethanol to an industrial-grade 316L stainless steel reactor, purge with nitrogen for protection, and add fluorinated silane and hexadecyltrimethoxysilane at a temperature of 25-30℃ and a stirring rate of 200-250r / min for 30-35min to obtain a silane complex solution.

[0011] Step a4: Add nano-silica to anhydrous ethanol, place it in an industrial-grade ultrasonic dispersion vessel, and disperse it at an ultrasonic power density of 0.8-1.0 W / cm³. 3 Under the condition of ultrasonic dispersion for 15-20 min, γ-aminopropyltriethoxysilane was added, and the mixture was stirred at 45-50℃ for 2 h. After the reaction was completed, the mixture was placed in an industrial vacuum dryer and dried at 75-80℃ for 4-5 h to obtain modified nano-silica.

[0012] Step a5: Add the modified nano-silica to the silane compound solution, start the probe-type ultrasonic reactor, and set the ultrasonic power density to 1.0-1.2 W / cm³. 3Under the conditions of ultrasonic dispersion for 30-35 min, during ultrasonication, every 10 min, ultrasonication is paused and mechanical stirring is started, stirring at 250 r / min for 5 min. After ultrasonication, mechanical stirring is maintained, and then the pH is adjusted to 3-4 with hydrochloric acid solution. Deionized water is added, and the addition time is controlled within 5 min. The temperature of the reaction system is raised to 30-32℃, and stirring is maintained for 30-35 min. The heating is turned off, and nitrogen protection and mechanical stirring are maintained. The mixture is further matured for 20-25 min to obtain the compound modified solution.

[0013] In a preferred embodiment of the present invention, the ratio of trifluoropropylmethylcyclotrisiloxane, anhydrous tetrahydrofuran, n-butyllithium-n-hexane solution, dimethylchlorosilane, n-hexane, and anhydrous sodium sulfate in step a1 is 11.7-19.5g: 10-16.7mL: 10-16.7mL: 2.99-4.99mL: 30-50mL: 5-6.6g.

[0014] In a preferred embodiment of the present invention, the concentration of the n-butyllithium-n-hexane solution in step a1 is 2.5 mol / L.

[0015] In a preferred embodiment of the present invention, the ratio of anhydrous toluene, vinyltrimethoxysilane, platinum(O)-1,3-diethylene-1,1,3,3-tetramethyldisiloxane and hydrogen-containing silane in step a2 is 15-17g: 8.47-9.68g: 7-8μL: 11.68-13.35g.

[0016] In a preferred embodiment of the present invention, the ratio of anhydrous ethanol, fluorinated silane and hexadecyltrimethoxysilane used in step a3 is 200-225 mL: 6.4-7.2 g: 1.6-1.8 g.

[0017] In a preferred embodiment of the present invention, the ratio of nano-silica, anhydrous ethanol and γ-aminopropyltriethoxysilane used in step a4 is 1-2g: 20-40mL: 0.1-0.2mL.

[0018] In a preferred embodiment of the present invention, the particle size of the nano-silica in step a4 is 20-50 nm.

[0019] In a preferred embodiment of the present invention, the ratio of the modified nano-silica, silane compound solution and deionized water in step a5 is 0.8-0.9g: 200-225mL: 0.2-0.225mL.

[0020] In a preferred embodiment of the present invention, the concentration of the hydrochloric acid solution in step a5 is 1 mol / L.

[0021] Secondly, this application provides a method for preparing hydrophobic and oleophilic magnetic fibers for oil-water separation, comprising the following steps:

[0022] Step 1: Weigh out 12-15 parts of the base material, 1-2 parts of the magnetite magnetic particles, 250-300 parts of distilled water, 0.01-0.03 parts of polyvinylpyrrolidone, and 200-220 parts of the compounded modification solution according to the following weight proportions, and set aside for later use;

[0023] Step 2: Wash the substrate with deionized water 2-3 times, soaking for 10-12 minutes each time. Then put it into a forced-air drying oven and dry it at 60-80℃ for 2-4 hours. After that, put it into an opening machine and open it at 800-1000r / min for 5-10 minutes to obtain the pre-treated recycled yarn.

[0024] Step 3: Add the ferric oxide magnetic particles to distilled water, add polyvinylpyrrolidone, and place the mixture in an industrial-grade ultrasonic dispersion tank. Disperse the mixture at an ultrasonic power density of 0.8-1.0 W / cm³. 3 Under the condition of ultrasonic dispersion for 30-60 min, the pretreated recycled fibers are then immersed in the dispersion solution and placed in a constant temperature mechanical stirrer. The mixture is stirred and adsorbed for 2-4 h at a temperature of 50-60℃ and a stirring rate of 300-330 r / min. The recycled fibers are then removed, excess water is squeezed out, and the mixture is placed in a forced-air drying oven and dried for 1-2 h at a temperature of 80-100℃ to obtain magnetic fluff.

[0025] Step 4: Add the magnetic fluff to an industrial-grade 316L stainless steel reactor, purge with nitrogen for protection, pour in the compound modification solution, and stir the reaction at a temperature of 40-45℃ and a stirring rate of 300-350 r / min for 2.5-2.7 h. After the reaction is complete, turn off the heating and allow it to cool naturally to room temperature. Then, place the fluff in a stainless steel separatory tank and wash it 2-3 times with anhydrous ethanol, and then wash it with deionized water until the pH of the washing solution is neutral. Place the washed fluff in an industrial-grade vacuum dryer and dry it at a temperature of 65-70℃ for 3-3.2 h to obtain hydrophobic and oleophilic magnetic fluff.

[0026] In a preferred embodiment of the present invention, the substrate in step one is made of cashmere or wool yarn recycled, with a fiber diameter of 10-30 μm and a length of 5-20 mm; the magnetic particles of iron oxide have a particle size of 50-200 nm; and the CAS number of the polyvinylpyrrolidone is 9003-39-8.

[0027] The beneficial effects of this invention are:

[0028] This invention discloses a hydrophobic and oleophilic magnetic flock for oil-water separation and its preparation method. The substrate is pretreated by washing, drying, and opening. Polyvinylpyrrolidone (PVP) is then adsorbed onto the surface of iron oxide (Fe3O4) nanoparticles through steric hindrance, preventing particle aggregation and forming a stable colloidal dispersion. When the Fe3O4-PVP colloid comes into contact with the pretreated recycled fibers, hydrogen bonds are formed between the hydroxyl groups on the fiber surface and the amide groups of PPVP. Simultaneously, the Fe3O4 particles are physically adsorbed onto the fiber surface through van der Waals forces. After the compounded modified liquid comes into contact with the magnetic flock, the active components wet the fiber and the surface of the Fe3O4 through capillary action. Silicon... The -Si(OH)3 generated by alkyl hydrolysis condenses with the hydroxyl groups of the substrate / magnetic particles to form Si-OC and Si-O-Fe covalent bonds. At the same time, silane molecules crosslink to form a continuous organic-inorganic composite coating. After purification and curing, a hydrophobic and oleophilic magnetic fluff is finally obtained. The low surface energy of trifluoropropyl in the coating endows the material with superhydrophobicity, while the long-chain alkyl of hexadecyl endows it with strong oleophilicity. The inorganic skeleton formed by modified nano-silica improves the wear resistance of the coating. The four functions of hydrophobicity, oleophilicity, magnetism and wear resistance are synergistically endowed to the cashmere / wool recycled substrate, and finally a magnetic fluff with both high-efficiency oil-water separation capability and convenient magnetic field recovery characteristics is formed.

[0029] In the preparation of hydrophobic and oleophilic magnetic fibers, a compound modified solution was prepared. First, n-butyllithium was used as an initiator to abstract electrons from the oxygen atom on the trifluoropropylmethylcyclotrisiloxane ring under ice-water bath conditions, breaking the ring strain and initiating ring-opening polymerization to form a linear polysiloxane active chain (with negatively charged active sites at the ends). Then, the Si-Cl bonds of dimethylchlorosilane react with the ends of the active chain, terminating chain growth and sealing the terminal active sites, while simultaneously generating a precipitate to prepare a linear fluorinated polysilane containing Si-H bonds. This introduces crosslinkable groups -Si(OC) for subsequent hydrosilylation. H3)3 lays the foundation, while introducing low surface energy groups through trifluoropropyl; then, the platinum (O)-1,3-diethylene-1,1,3,3-tetramethyldisiloxane catalyst coordinates with vinyltrimethoxysilane to activate the catalytic activity of Pt. After heating, the Si-H bond of the hydrogen-containing silane and the C=C double bond of vinyltrimethoxysilane undergo an addition reaction under Pt catalysis. The Si-H bond breaks and combines with the C=C double bond, grafting the -Si(OCH3)3 group of vinyltrimethoxysilane onto the polysilane backbone, introducing hydrolyzable groups into the fluorinated polysilane. -Si(OCH3)3 groups (subsequent crosslinking core) are used, while retaining the hydrophobic properties of trifluoropropyl groups. Subsequently, fluorinated silanes (hydrophobic cores) and hexadecyltrimethoxysilanes (lipophilic cores) are uniformly dispersed in anhydrous ethanol, forming a stable mixture system through van der Waals forces, thus imparting hydrophobic and lipophilic properties. Nano-silica is modified with γ-aminopropyltriethoxysilane, changing its surface from hydrophilic to organophilic, improving its dispersibility in silane complexes, and introducing amino groups to enhance its interaction with subsequent silane hydrolysis products. Finally, the modified nano-silica... Silica is uniformly dispersed in a silane compound solution by ultrasonic dispersion. The amino groups on the surface of nano-silica form hydrogen bonds with silane molecules, inhibiting aggregation. The pH is adjusted to the optimal acidic conditions for silane hydrolysis by hydrochloric acid. Deionized water is added to trigger the hydrolysis of the -Si(OCH3)3 groups of fluorinated silane and hexadecyltrimethoxysilane, generating -Si(OH)3. Slight condensation occurs between the -Si(OH)3 generated by silane hydrolysis and between -Si(OH)3 and the hydroxyl / amino groups on the surface of nano-silica, forming a preliminary cross-linked organic-inorganic composite dispersion system.The trifluoropropyl group in fluorinated silanes is a low surface energy group that can quickly repel water, preventing separation failure caused by water wetting. Furthermore, the fluorinated group exhibits strong chemical stability, maintaining its hydrophobic properties even in acidic or alkaline water. The long-chain alkyl group of hexadecyltrimethoxysilane has excellent compatibility with various oil phases, significantly improving the material's oil adsorption rate, especially suitable for separating high-viscosity crude oils. The synergistic effect of the hydrophobic and lipophilic groups enables magnetic fibers to quickly achieve oil-water phase separation, resulting in high and stable separation efficiency. Fluorinated silanes and hexadecyltrimethoxysilane... All contain hydrolyzable -Si(OCH3)3 groups. The resulting silanol groups after hydrolysis can undergo condensation reactions with the hydroxyl groups on the surface of the magnetic flock substrate and the surface of the iron oxide magnetic particles, forming Si-OC and Si-O-Fe covalent bonds. This results in coating adhesion far exceeding physical adsorption, preventing detachment due to friction or immersion. Modified nano-silica is uniformly dispersed in the coating; its high hardness fills the coating pores, forming an organic-inorganic composite framework, thus improving the wear resistance of the magnetic flock and significantly enhancing the coating's durability and chemical stability. Detailed Implementation

[0030] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0031] Example 1:

[0032] This embodiment describes a method for preparing hydrophobic and oleophilic magnetic fibers for oil-water separation, comprising the following steps:

[0033] Step s1: Add 11.7g of trifluoropropylmethylcyclotrisiloxane to an industrial-grade 316L stainless steel reactor. Vacuum and nitrogen purging are performed on the system using a vacuum unit and nitrogen buffer tank. This process is repeated three times. Then, 10mL of anhydrous tetrahydrofuran is added to the reactor using a metering pump. The reactor jacket is circulated with chilled brine to stabilize the system temperature at 0℃. 10mL of n-butyllithium-n-hexane solution (concentration of n-butyllithium-n-hexane solution is 2.5mol / L) is added, and the reaction is carried out for 2 hours. Then, 2.99mL of dimethylchlorosilane is added, and the reaction is carried out at room temperature for 12 hours. After that, 30mL of n-hexane is added and stirred. The mixture is then transferred to a stainless steel separatory tank, and the organic phase is washed three times with deionized water. 5g of anhydrous sodium sulfate is added, and the mixture is allowed to stand and dry for 4 hours. The precipitate is removed by filtration, and then the mixture is distilled under reduced pressure at 80℃ to obtain hydrogen-containing silane.

[0034] Step s2: 15g of anhydrous toluene, 8.47g of vinyltrimethoxysilane and 7μL of platinum(O)-1,3-diethylene-1,1,3,3-tetramethyldisiloxane were added to an industrial-grade 316L stainless steel reactor. Nitrogen gas was introduced for protection. The mixture was stirred for 20min at 25℃ and a stirring rate of 300r / min. The temperature was raised to 80℃ and 11.68g of hydrogen-containing silane was added dropwise over 4h. After the addition was completed, the reaction continued for 20h. Then, the mixture was distilled under reduced pressure at 100℃ to obtain fluorinated silane.

[0035] Step s3: Add 200 mL of anhydrous ethanol to an industrial-grade 316L stainless steel reactor, purge with nitrogen for protection, and add 6.4 g of fluorinated silane and 1.6 g of hexadecyltrimethoxysilane at a temperature of 25 °C and a stirring rate of 200 r / min. Stir for 30 min to obtain a silane complex solution.

[0036] Step s4: Add 1g of nano-silica (particle size of 20nm) to 20mL of anhydrous ethanol, place it in an industrial-grade ultrasonic dispersion vessel, and disperse at an ultrasonic power density of 0.8W / cm³. 3 Under the condition of ultrasonic dispersion for 15 min, 0.1 mL of γ-aminopropyltriethoxysilane was added, and the mixture was stirred at 45 °C for 2 h. After the reaction was completed, the mixture was placed in an industrial vacuum dryer and dried at 75 °C for 4 h to obtain modified nano-silica.

[0037] Step s5: Add 0.8g of modified nano-silica to 200mL of silane compound solution, start the probe-type ultrasonic reactor, and set the ultrasonic power density to 1.0W / cm³. 3 Under the conditions of ultrasonic dispersion for 30 min, during ultrasonication, every 10 min, ultrasonication was paused and mechanical stirring was started, and stirred at 250 r / min for 5 min. After ultrasonication, mechanical stirring was maintained, and then the pH was adjusted to 3 with 1 mol / L hydrochloric acid solution. 0.2 mL of deionized water was added, and the addition time was controlled within 5 min. The temperature of the reaction system was raised to 30℃ and stirred for 30 min. The heating was turned off, and nitrogen protection and mechanical stirring were maintained. The mixture was further matured for 20 min to obtain the compound modified solution.

[0038] Step s6: Weigh out 12 parts of the base material, 1 part of the magnetite magnetic particles, 250 parts of distilled water, 0.01 parts of polyvinylpyrrolidone, and 200 parts of the compound modification solution according to the weight ratio, and set aside.

[0039] Step s7: Wash the substrate (the substrate is cashmere or wool yarn recycled, with a fiber diameter of 10μm and a length of 5mm) twice with deionized water, soaking for 10 minutes each time. Then put it into a forced-air drying oven and dry it at a temperature of 60℃ for 2 hours. After that, put it into an opening machine and open it for 5 minutes at a speed of 800r / min to obtain the pretreated recycled yarn.

[0040] Step s8: Add the magnetite (with a particle size of 50 nm) to distilled water, add polyvinylpyrrolidone (CAS number 9003-39-8), and place the mixture in an industrial-grade ultrasonic dispersion vessel. Disperse the mixture at an ultrasonic power density of 0.8 W / cm³. 3 Under the condition of ultrasonic dispersion for 30 min, the pretreated recycled fibers were then immersed in the dispersion solution and placed in a constant temperature mechanical stirrer. The mixture was stirred and adsorbed for 2 h at a temperature of 50℃ and a stirring rate of 300 r / min. The recycled fibers were then removed, excess water was squeezed out, and the mixture was placed in a forced-air drying oven and dried for 1 h at a temperature of 80℃ to obtain magnetic fluff.

[0041] Step s9: Add the magnetic fluff to an industrial-grade 316L stainless steel reactor, purge with nitrogen for protection, pour in the compound modified solution, and stir the reaction at 40℃ and 300r / min for 2.5-2.7h. After the reaction is complete, turn off the heating and allow it to cool naturally to room temperature. Then, place the fluff in a stainless steel separatory tank, wash it twice with anhydrous ethanol, and then wash it with deionized water until the pH of the washing solution is neutral. Place the washed fluff in an industrial-grade vacuum dryer and dry it at 65℃ for 3h to obtain hydrophobic and oleophilic magnetic fluff.

[0042] Example 2:

[0043] This embodiment describes a method for preparing hydrophobic and oleophilic magnetic fibers for oil-water separation, comprising the following steps:

[0044] Step s1: Add 15.7g of trifluoropropylmethylcyclotrisiloxane to an industrial-grade 316L stainless steel reactor. Vacuum and nitrogen purging are performed on the system using a vacuum unit and nitrogen buffer tank. This process is repeated three times. Then, 13.3mL of anhydrous tetrahydrofuran is added to the reactor using a metering pump. The reactor jacket is circulated with chilled brine to stabilize the system temperature at 3℃. Add 13.3mL of n-butyllithium-n-hexane solution (2.5mol / L). React for 2.1h. Add 3.99mL of dimethylchlorosilane and react at room temperature for 12.5h. Then, add 40mL of n-hexane and stir. Transfer the mixture to a stainless steel separatory tank. Wash the organic phase three times with deionized water. Add 5.8g of anhydrous sodium sulfate and let it stand and dry for 4.1h. Filter to remove the precipitate. Then, distill under reduced pressure at 85℃ to obtain hydrogen-containing silane.

[0045] Step s2: 16g of anhydrous toluene, 9g of vinyltrimethoxysilane and 7.5μL of platinum(O)-1,3-diethylene-1,1,3,3-tetramethyldisiloxane were added to an industrial-grade 316L stainless steel reactor. Nitrogen gas was introduced for protection. The mixture was stirred for 25min at 27℃ and a stirring rate of 330r / min. The temperature was raised to 83℃ and 12.25g of hydrogen-containing silane was added dropwise over 4h. After the addition was completed, the reaction continued for 21h. Then, the mixture was distilled under reduced pressure at 105℃ to obtain fluorinated silane.

[0046] Step s3: Add 212 mL of anhydrous ethanol to an industrial-grade 316L stainless steel reactor, purge with nitrogen for protection, and add 6.8 g of fluorinated silane and 1.7 g of hexadecyltrimethoxysilane at a temperature of 27 °C and a stirring rate of 220 r / min. Stir for 33 min to obtain a silane complex solution.

[0047] Step s4: Add 1.5g of nano-silica (30nm particle size) to 30mL of anhydrous ethanol, place in an industrial-grade ultrasonic dispersion vessel, and ultrasonically disperse at a power density of 0.9W / cm³. 3 Under the condition of ultrasonic dispersion for 17 min, 0.15 mL of γ-aminopropyltriethoxysilane was added, and the mixture was stirred at 47 °C for 2 h. After the reaction was completed, the mixture was placed in an industrial-grade vacuum dryer and dried at 77 °C for 4.5 h to obtain modified nano-silica.

[0048] Step s5: Add 0.85g of modified nano-silica to 212mL of silane compound solution, start the probe-type ultrasonic reactor, and set the ultrasonic power density to 1.1W / cm². 3Under the conditions of ultrasonic dispersion for 33 min, during ultrasonication, every 10 min, ultrasonication was paused and mechanical stirring was started, and stirred for 5 min at a speed of 250 r / min. After ultrasonication, mechanical stirring was maintained, and then the pH was adjusted to 3 with 1 mol / L hydrochloric acid solution. 0.212 mL of deionized water was added, and the addition time was controlled within 5 min. The temperature of the reaction system was raised to 31℃ and stirred for 33 min. The heating was turned off, and nitrogen protection and mechanical stirring were maintained. The mixture was further matured for 23 min to obtain the compound modified solution.

[0049] Step s6: Weigh out 13.5 parts of the base material, 1.5 parts of the magnetite particles, 270 parts of distilled water, 0.02 parts of polyvinylpyrrolidone, and 210 parts of the compounded modification solution according to the following weight proportions, and set aside for later use;

[0050] Step s7: Wash the substrate (the substrate is cashmere or wool yarn recycled, with a fiber diameter of 20μm and a length of 8mm) twice with deionized water, soaking for 11 minutes each time. Then put it into a forced-air drying oven and dry it at a temperature of 70℃ for 3 hours. After that, put it into an opening machine and open it at a speed of 900r / min for 7 minutes to obtain the pretreated recycled yarn.

[0051] Step s8: Add the magnetite (magnetic particles with a particle size of 120 nm) to distilled water, add polyvinylpyrrolidone (CAS number 9003-39-8), and place the mixture in an industrial-grade ultrasonic dispersion vessel. Dispersion is carried out at an ultrasonic power density of 0.9 W / cm³. 3 Under the condition of ultrasonic dispersion for 45 min, the pretreated recycled fibers were then immersed in the dispersion and placed in a constant temperature mechanical stirrer. The mixture was stirred and adsorbed for 3 h at a temperature of 55℃ and a stirring rate of 310 r / min. The recycled fibers were then removed, excess water was squeezed out, and the mixture was placed in a forced-air drying oven and dried for 1.5 h at a temperature of 90℃ to obtain magnetic fluff.

[0052] Step s9: Add the magnetic fluff to an industrial-grade 316L stainless steel reactor, purge with nitrogen for protection, pour in the compound modified solution, and stir the reaction at 43℃ and 330r / min for 2.6h. After the reaction is complete, turn off the heating and allow it to cool naturally to room temperature. Then, place the fluff in a stainless steel separatory tank, wash it twice with anhydrous ethanol, and then wash it with deionized water until the pH of the washing solution is neutral. Place the washed fluff in an industrial-grade vacuum dryer and dry it at 67℃ for 3.1h to obtain hydrophobic and oleophilic magnetic fluff.

[0053] Example 3:

[0054] This embodiment describes a method for preparing hydrophobic and oleophilic magnetic fibers for oil-water separation, comprising the following steps:

[0055] Step s1: Add 19.5g of trifluoropropylmethylcyclotrisiloxane to an industrial-grade 316L stainless steel reactor. Vacuum and nitrogen purging are performed on the system using a vacuum unit and nitrogen buffer tank. This process is repeated three times. Then, 16.7mL of anhydrous tetrahydrofuran is added to the reactor using a metering pump. The reactor jacket is circulated with chilled brine to stabilize the system temperature at 5℃. 16.7mL of n-butyllithium-n-hexane solution (concentration of n-butyllithium-n-hexane solution is 2.5mol / L) is added, and the reaction is carried out for 2.2h. Then, 4.99mL of dimethylchlorosilane is added, and the reaction is carried out at room temperature for 13h. After that, 50mL of n-hexane is added and stirred. The mixture is then transferred to a stainless steel separatory tank, and the organic phase is washed four times with deionized water. 6.6g of anhydrous sodium sulfate is added, and the mixture is allowed to stand and dry for 4.2h. The precipitate is removed by filtration, and then the mixture is distilled under reduced pressure at 90℃ to obtain hydrogen-containing silane.

[0056] Step s2: 17g of anhydrous toluene, 9.68g of vinyltrimethoxysilane and 8μL of platinum(O)-1,3-diethylene-1,1,3,3-tetramethyldisiloxane were added to an industrial-grade 316L stainless steel reactor. Nitrogen gas was introduced for protection. The mixture was stirred for 30 min at 30℃ and a stirring rate of 350 r / min. The temperature was raised to 85℃, and 13.35g of hydrogen-containing silane was added dropwise over 4 h. After the addition was completed, the reaction continued for 22 h. Then, the mixture was distilled under reduced pressure at 110℃ to obtain fluorinated silane.

[0057] Step s3: Add 225 mL of anhydrous ethanol to an industrial-grade 316L stainless steel reactor, purge with nitrogen for protection, and add 7.2 g of fluorinated silane and 1.8 g of hexadecyltrimethoxysilane at a temperature of 30 °C and a stirring rate of 250 r / min. Stir for 35 min to obtain a silane complex solution.

[0058] Step s4: Add 2g of nano-silica (50nm particle size) to 40mL of anhydrous ethanol, place in an industrial-grade ultrasonic dispersion vessel, and ultrasonically disperse at a power density of 1.0W / cm³. 3 Under the condition of ultrasonic dispersion for 20 min, 0.2 mL of γ-aminopropyltriethoxysilane was added, and the mixture was stirred at 50 °C for 2 h. After the reaction was completed, the mixture was placed in an industrial-grade vacuum dryer and dried at 80 °C for 5 h to obtain modified nano-silica.

[0059] Step s5: Add 0.9g of modified nano-silica to 225mL of silane compound solution, start the probe-type ultrasonic reactor, and set the ultrasonic power density to 1.2W / cm³. 3Under the conditions of ultrasonic dispersion for 35 min, during ultrasonication, every 10 min, ultrasonication was paused and mechanical stirring was started, and stirred for 5 min at a speed of 250 r / min. After ultrasonication, mechanical stirring was maintained, and then the pH was adjusted to 4 with 1 mol / L hydrochloric acid solution. 0.225 mL of deionized water was added, and the addition time was controlled within 5 min. The temperature of the reaction system was raised to 32℃ and stirred for 35 min. The heating was turned off, and nitrogen protection and mechanical stirring were maintained. The mixture was further matured for 25 min to obtain the compound modified solution.

[0060] Step s6: Weigh out 15 parts of the base material, 2 parts of the magnetite magnetic particles, 300 parts of distilled water, 0.03 parts of polyvinylpyrrolidone, and 220 parts of the compounded modification solution according to the following weight proportions, and set aside for later use;

[0061] Step s7: Wash the substrate (the substrate is cashmere or wool yarn waste with a fiber diameter of 30μm and a length of 20mm) with deionized water 3 times, soaking for 12min each time. Then put it into a forced-air drying oven and dry it at 80℃ for 4h. After that, put it into an opening machine and open it for 10min at a speed of 1000r / min to obtain the pretreated waste yarn.

[0062] Step s8: Add the magnetite (magnetic particles with a particle size of 200 nm) to distilled water, add polyvinylpyrrolidone (CAS number 9003-39-8), and place the mixture in an industrial-grade ultrasonic dispersion vessel. Dispersion is carried out at an ultrasonic power density of 1.0 W / cm³. 3 Under the condition of ultrasonic dispersion for 60 min, the pretreated recycled fibers were then immersed in the dispersion and placed in a constant temperature mechanical stirrer. The mixture was stirred and adsorbed for 4 h at a temperature of 60℃ and a stirring rate of 330 r / min. The recycled fibers were then removed, excess water was squeezed out, and the mixture was placed in a forced-air drying oven and dried for 2 h at a temperature of 100℃ to obtain magnetic fluff.

[0063] Step s9: Add the magnetic fluff to an industrial-grade 316L stainless steel reactor, purge with nitrogen for protection, pour in the compound modified solution, and stir the reaction at 45℃ and 350r / min for 2.7h. After the reaction is complete, turn off the heating and allow it to cool naturally to room temperature. Then, place the fluff in a stainless steel separatory tank, wash it three times with anhydrous ethanol, and then wash it with deionized water until the pH of the washing solution is neutral. Place the washed fluff in an industrial-grade vacuum dryer and dry it at 70℃ for 3.2h to obtain hydrophobic and oleophilic magnetic fluff.

[0064] Comparative Example 1:

[0065] This comparative example illustrates a method for preparing hydrophobic and oleophilic magnetic fibers for oil-water separation, comprising the following steps:

[0066] Step s1: Add 11.7g of trifluoropropylmethylcyclotrisiloxane to an industrial-grade 316L stainless steel reactor. Vacuum and nitrogen purging are performed on the system using a vacuum unit and nitrogen buffer tank. This process is repeated three times. Then, 10mL of anhydrous tetrahydrofuran is added to the reactor using a metering pump. The reactor jacket is circulated with chilled brine to stabilize the system temperature at 0℃. 10mL of n-butyllithium-n-hexane solution (concentration of n-butyllithium-n-hexane solution is 2.5mol / L) is added, and the reaction is carried out for 2 hours. Then, 2.99mL of dimethylchlorosilane is added, and the reaction is carried out at room temperature for 12 hours. After that, 30mL of n-hexane is added and stirred. The mixture is then transferred to a stainless steel separatory tank, and the organic phase is washed three times with deionized water. 5g of anhydrous sodium sulfate is added, and the mixture is allowed to stand and dry for 4 hours. The precipitate is removed by filtration, and then the mixture is distilled under reduced pressure at 80℃ to obtain hydrogen-containing silane.

[0067] Step s2: 15g of anhydrous toluene, 8.47g of vinyltrimethoxysilane and 7μL of platinum(O)-1,3-diethylene-1,1,3,3-tetramethyldisiloxane were added to an industrial-grade 316L stainless steel reactor. Nitrogen gas was introduced for protection. The mixture was stirred for 20min at 25℃ and a stirring rate of 300r / min. The temperature was raised to 80℃ and 11.68g of hydrogen-containing silane was added dropwise over 4h. After the addition was completed, the reaction continued for 20h. Then, the mixture was distilled under reduced pressure at 100℃ to obtain fluorinated silane.

[0068] Step s3: Add 200 mL of anhydrous ethanol to an industrial-grade 316L stainless steel reactor, purge with nitrogen for protection, and add 6.4 g of fluorinated silane and 1.6 g of hexadecyltrimethoxysilane at a temperature of 25 °C and a stirring rate of 200 r / min. Stir for 30 min to obtain a silane complex solution.

[0069] Step s4: Place 200 mL of silane compound solution into a probe-type ultrasonic reactor, and run the ultrasonic power at a density of 1.0 W / cm². 3 Under the conditions of ultrasonic dispersion for 30 min, during ultrasonication, every 10 min, ultrasonication was paused and mechanical stirring was started, and stirred at 250 r / min for 5 min. After ultrasonication, mechanical stirring was maintained, and then the pH was adjusted to 3 with 1 mol / L hydrochloric acid solution. 0.2 mL of deionized water was added, and the addition time was controlled within 5 min. The temperature of the reaction system was raised to 30℃ and stirred for 30 min. The heating was turned off, and nitrogen protection and mechanical stirring were maintained. The mixture was further matured for 20 min to obtain the compound modified solution.

[0070] Step s5: Weigh out 12 parts of the base material, 1 part of the magnetite magnetic particles, 250 parts of distilled water, 0.01 parts of polyvinylpyrrolidone, and 200 parts of the compound modification solution according to the weight ratio, and set aside.

[0071] Step s6: Wash the substrate (the substrate is cashmere or wool yarn recycled, with a fiber diameter of 10μm and a length of 5mm) twice with deionized water, soaking for 10 minutes each time. Then put it into a forced-air drying oven and dry it at a temperature of 60℃ for 2 hours. After that, put it into an opening machine and open it for 5 minutes at a speed of 800r / min to obtain the pretreated recycled yarn.

[0072] Step s7: Add magnetite (with a particle size of 50 nm) to distilled water, add polyvinylpyrrolidone (CAS number 9003-39-8), and place in an industrial-grade ultrasonic dispersion vessel. Disperse the mixture at an ultrasonic power density of 0.8 W / cm³. 3 Under the condition of ultrasonic dispersion for 30 min, the pretreated recycled fibers were then immersed in the dispersion solution and placed in a constant temperature mechanical stirrer. The mixture was stirred and adsorbed for 2 h at a temperature of 50℃ and a stirring rate of 300 r / min. The recycled fibers were then removed, excess water was squeezed out, and the mixture was placed in a forced-air drying oven and dried for 1 h at a temperature of 80℃ to obtain magnetic fluff.

[0073] Step s8: Add the magnetic fluff to an industrial-grade 316L stainless steel reactor, purge with nitrogen for protection, pour in the compound modification solution, and stir the reaction at 40℃ and 300r / min for 2.5-2.7h. After the reaction is complete, turn off the heating and allow it to cool naturally to room temperature. Then, place the fluff in a stainless steel separatory tank, wash it twice with anhydrous ethanol, and then wash it with deionized water until the pH of the washing solution is neutral. Place the washed fluff in an industrial-grade vacuum dryer and dry it at 65℃ for 3h to obtain hydrophobic and oleophilic magnetic fluff.

[0074] Comparative Example 2:

[0075] This comparative example illustrates a method for preparing hydrophobic and oleophilic magnetic fibers for oil-water separation, comprising the following steps:

[0076] Step s1: Add 200 mL of anhydrous ethanol to an industrial-grade 316L stainless steel reactor, purge with nitrogen for protection, and add 6.4 g of methyltrimethoxysilane and 1.6 g of hexadecyltrimethoxysilane at a temperature of 25 °C and a stirring rate of 200 r / min. Stir for 30 min to obtain a silane complex solution.

[0077] Step s2: Add 1g of nano-silica (particle size of 20nm) to 20mL of anhydrous ethanol, place it in an industrial-grade ultrasonic dispersion vessel, and disperse it at an ultrasonic power density of 0.8W / cm³. 3 Under the condition of ultrasonic dispersion for 15 min, 0.1 mL of γ-aminopropyltriethoxysilane was added, and the mixture was stirred at 45 °C for 2 h. After the reaction was completed, the mixture was placed in an industrial vacuum dryer and dried at 75 °C for 4 h to obtain modified nano-silica.

[0078] Step s3: Add 0.8g of modified nano-silica to 200mL of silane compound solution, start the probe-type ultrasonic reactor, and set the ultrasonic power density to 1.0W / cm³. 3 Under the conditions of ultrasonic dispersion for 30 min, during ultrasonication, every 10 min, ultrasonication was paused and mechanical stirring was started, and stirred at 250 r / min for 5 min. After ultrasonication, mechanical stirring was maintained, and then the pH was adjusted to 3 with 1 mol / L hydrochloric acid solution. 0.2 mL of deionized water was added, and the addition time was controlled within 5 min. The temperature of the reaction system was raised to 30℃ and stirred for 30 min. The heating was turned off, and nitrogen protection and mechanical stirring were maintained. The mixture was further matured for 20 min to obtain the compound modified solution.

[0079] Step s4: Weigh out 12 parts of the base material, 1 part of the magnetite magnetic particles, 250 parts of distilled water, 0.01 parts of polyvinylpyrrolidone, and 200 parts of the compound modification solution according to the weight ratio, and set aside.

[0080] Step s5: Wash the substrate (the substrate is cashmere or wool yarn recycled, with a fiber diameter of 10μm and a length of 5mm) twice with deionized water, soaking for 10 minutes each time. Then put it into a forced-air drying oven and dry it at 60℃ for 2 hours. After that, put it into an opening machine and open it for 5 minutes at a speed of 800r / min to obtain the pretreated recycled yarn.

[0081] Step s6: Add the magnetite (with a particle size of 50 nm) to distilled water, add polyvinylpyrrolidone (CAS number 9003-39-8), and place the mixture in an industrial-grade ultrasonic dispersion vessel. Disperse the mixture at an ultrasonic power density of 0.8 W / cm³. 3 Under the condition of ultrasonic dispersion for 30 min, the pretreated recycled fibers were then immersed in the dispersion solution and placed in a constant temperature mechanical stirrer. The mixture was stirred and adsorbed for 2 h at a temperature of 50℃ and a stirring rate of 300 r / min. The recycled fibers were then removed, excess water was squeezed out, and the mixture was placed in a forced-air drying oven and dried for 1 h at a temperature of 80℃ to obtain magnetic fluff.

[0082] Step s7: Add the magnetic fluff to an industrial-grade 316L stainless steel reactor, purge with nitrogen for protection, pour in the compound modification solution, and stir the reaction at 40℃ and 300r / min for 2.5-2.7h. After the reaction is complete, turn off the heating and allow it to cool naturally to room temperature. Then, place the fluff in a stainless steel separatory tank, wash it twice with anhydrous ethanol, and then wash it with deionized water until the pH of the washing solution is neutral. Place the washed fluff in an industrial-grade vacuum dryer and dry it at 65℃ for 3h to obtain hydrophobic and oleophilic magnetic fluff.

[0083] Comparative Example 3:

[0084] This comparative example illustrates a method for preparing hydrophobic and oleophilic magnetic fibers for oil-water separation, comprising the following steps:

[0085] Step s1: Add 200 mL of anhydrous ethanol to an industrial-grade 316L stainless steel reactor, purge with nitrogen for protection, and add 1.6 g of hexadecyltrimethoxysilane at a temperature of 25℃ and a stirring rate of 200 r / min. Stir for 30 min to obtain a silane solution.

[0086] Step s2: Weigh out 12 parts of the substrate, 1 part of the magnetite magnetic particles, 250 parts of distilled water, 0.01 parts of polyvinylpyrrolidone, and 200 parts of silane solution according to the weight ratio, and set aside.

[0087] Step s3: Wash the substrate (the substrate is cashmere or wool yarn recycled, with a fiber diameter of 10μm and a length of 5mm) twice with deionized water, soaking for 10 minutes each time. Then put it into a forced-air drying oven and dry it at a temperature of 60℃ for 2 hours. After that, put it into an opening machine and open it for 5 minutes at a speed of 800r / min to obtain the pretreated recycled yarn.

[0088] Step s4: Add magnetite (with a particle size of 50 nm) to distilled water, add polyvinylpyrrolidone (CAS number 9003-39-8), and place in an industrial-grade ultrasonic dispersion vessel. Disperse the mixture at an ultrasonic power density of 0.8 W / cm³. 3 Under the condition of ultrasonic dispersion for 30 min, the pretreated recycled fibers were then immersed in the dispersion solution and placed in a constant temperature mechanical stirrer. The mixture was stirred and adsorbed for 2 h at a temperature of 50℃ and a stirring rate of 300 r / min. The recycled fibers were then removed, excess water was squeezed out, and the mixture was placed in a forced-air drying oven and dried for 1 h at a temperature of 80℃ to obtain magnetic fluff.

[0089] Step s5: Add the magnetic fluff to an industrial-grade 316L stainless steel reactor, purge with nitrogen for protection, pour in the compound modification solution, and stir the reaction at 40℃ and 300r / min for 2.5-2.7h. After the reaction is complete, turn off the heating and allow it to cool naturally to room temperature. Then, place the fluff in a stainless steel separatory tank, wash it twice with anhydrous ethanol, and then wash it with deionized water until the pH of the washing solution is neutral. Place the washed fluff in an industrial-grade vacuum dryer and dry it at 65℃ for 3h to obtain hydrophobic and oleophilic magnetic fluff.

[0090] Performance testing

[0091] The hydrophobic and oleophilic magnetic fibers of Examples 1-3 and Comparative Examples 1-3 were tested for performance according to the following method;

[0092] Water contact angle and oil contact angle were tested according to GB / T 30693-2014 "Measurement of contact angle between plastic film and water". Under the conditions of 25℃ temperature and 50% RH humidity, 5μL of deionized water (or diesel) was dropped onto the surface of the fluff sample using a micro metering pump. The image was taken by the contact angle measuring instrument and the angle was calculated. Five different points were tested for each sample and the average value was taken.

[0093] Adsorption capacity test: Accurately weigh the mass (m0) of the dried fluff sample, immerse it in diesel oil at 25℃ and let it stand for 1 hour. After taking it out, use filter paper to remove the surface oil and immediately weigh the mass (m1) after adsorption. Adsorption capacity = (m1-m0) / m0. Perform three parallel tests and take the average value.

[0094] Test magnetic response time: Refer to the magnetic field environment setting requirements in GB / T 3217-2013 "Magnetic Test Methods for Permanent Magnet (Hard Magnet) Materials". Disperse the fluff sample in 100mL of deionized water (simulating the actual medium of oil-water separation) and place it in a constant magnetic field of 0.1T. Record the time from the sample to complete aggregation and adsorption to the magnetic field source. Perform three parallel tests and take the average value.

[0095] Test cycle count: Dry the sample under vacuum at 65℃ to constant weight, denoted as m0. Adsorption: Immerse the sample in diesel oil at room temperature for 1 hour until saturated, weigh the total mass after adsorption, denoted as m1, and calculate the initial adsorption capacity Q1 = (m1 - m0) / m0. Desorption: Place the saturated sample in a beaker containing anhydrous ethanol, and ultrasonically elute for 5 minutes at 300W. Regeneration: Rinse once with deionized water, and dry under vacuum at 65℃ to constant weight (denoted as m2; a deviation from m0 ≤ 0.001g is considered complete regeneration). Cycling: Repeat adsorption-desorption-regeneration, and calculate the adsorption capacity Q after each cycle. n =(m n -m n-1 ) / m0,m nThe mass after the nth adsorption is given, up to the adsorption capacity Q at a certain time. n If the result is less than 0.9 × Q1, stop the loop, record the total number of loops, and perform three parallel tests to take the average value.

[0096] Separation efficiency test: 90 mL of water and 10 mL of diesel oil were stirred at 25℃ and 15000 r / min for 5 min. The hydrophobic and oleophilic magnetic villous material was weighed (the mass was calculated according to "adsorption capacity × 1.2" to ensure complete adsorption, and recorded as m sample). It was added to the above oil-water emulsion and stirred at 300 r / min for 10 min. The mixture was allowed to stand for 2 min to aggregate. 50 mL of the supernatant was extracted with 10 mL of n-hexane for 5 min. The mass of diesel oil in the mixture was determined by infrared spectrophotometry (recorded as m residue). m residue total = 2 × m residue. The separation efficiency η = (8.4 - m residue total) / 8.4 × 100% (the density of diesel oil is 0.84 g / mL). The average value was taken from 3 parallel tests.

[0097] The test results are shown in the table below:

[0098]

[0099] Referring to the table above, based on the comparison between Examples 1-3 and Comparative Examples 1-3, it can be seen that the hydrophobic and oleophilic magnetic fluff has four major functions: hydrophobicity, oleophilicity, magnetism, and wear resistance, ultimately forming a magnetic fluff that combines efficient oil-water separation capability and convenient magnetic field recovery characteristics.

[0100] Based on the comparison between Example 1 and Comparative Example 1, it can be seen that in Comparative Example 1, no modified nano-silica was added. The rough structure provided by nano-silica is the key to superhydrophobicity. Without the rough structure, the water contact angle drops from the superhydrophobic range (≥150°) to ordinary hydrophobicity. The surface porosity is insufficient. The synergistic effect of the rough structure and fluorine-containing groups ensures oleophilicity. The reduced oil phase adhesion area leads to a decrease in adsorption capacity. The coating lacks nanoparticle anchoring, resulting in decreased adhesion and easy detachment, which leads to a halving of the number of cycles.

[0101] Based on the comparison between Example 1 and Comparative Example 2, it can be seen that in Comparative Example 2, the modified liquid was replaced with an equal mass of methyltrimethoxysilane instead of fluorinated silane, while the modified nano-silica and hexadecyltrimethoxysilane were retained. The process remained unchanged. The lipophilicity of the fluorinated group was much better than that of the methyl group, and the surface energy of methylsilane had a low matching degree with oil, resulting in a significant decrease in lipophilicity. This led to a significant drop in the water contact angle to 112.4° (no superhydrophobic properties) and an increase in the oil contact angle to 20.6° (weakened lipophilicity). The chemical stability (solvent resistance and mechanical friction resistance) of the fluorinated silane was much better than that of methylsilane. Methylsilane is prone to molecular chain breakage or coating peeling during the cycle, thus the number of cycles decreased significantly, the adsorption capacity decreased, and the oil phase was difficult to wet and adsorb quickly, resulting in insufficient separation efficiency. The weak solvent resistance of the non-fluorinated coating resulted in poor cycle stability.

[0102] Based on the comparison between Example 1 and Comparative Example 3, it can be seen that in Comparative Example 3, no modified nano-silica and fluorinated silane were added, resulting in a water contact angle close to 90° (hydrophobic failure, tending towards hydrophilicity), an oil contact angle of 38.6° (significantly insufficient oleophilicity), an adsorption capacity of only 6.5 g / g, a separation efficiency of less than 80%, and only 5 cycles, which is completely unable to meet the actual oil-water separation requirements.

[0103] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0104] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in this application, they should all fall within the protection scope of the present invention.

Claims

1. A hydrophobic and oleophilic magnetic fluff for oil-water separation, characterized in that, Includes the following components by weight: The substrate consists of 12-15 parts, magnetite magnetic particles of 1-2 parts, distilled water of 250-300 parts, polyvinylpyrrolidone of 0.01-0.03 parts, and compounded modification solution of 200-220 parts. The modified compound solution is prepared by the following steps: Step a1: Trifluoropropylmethylcyclotrisiloxane was added to an industrial-grade 316L stainless steel reactor, anhydrous tetrahydrofuran was added, then n-butyllithium-n-hexane solution was added to react, dimethylchlorosilane was added to react, then n-hexane was added and stirred, washed, anhydrous sodium sulfate was added, allowed to stand and dry, filtered, and then distilled under reduced pressure to obtain hydrogen-containing silane. Step a2: Anhydrous toluene, vinyltrimethoxysilane and platinum (0)-1,3-diethylene-1,1,3,3-tetramethyldisiloxane were added to an industrial-grade 316L stainless steel reactor and stirred to react. The temperature was raised, and hydrogen-containing silane was added dropwise to react. The mixture was then distilled under reduced pressure to obtain fluorinated silane. Step a3: Add anhydrous ethanol to an industrial-grade 316L stainless steel reactor, add fluorinated silane and hexadecyltrimethoxysilane and stir to obtain silane complex solution; Step a4: Add nano-silica to anhydrous ethanol and disperse it by ultrasonication, then add γ-aminopropyltriethoxysilane and stir, then dry to obtain modified nano-silica; Step a5: Add the modified nano-silica to the silane compound solution and disperse it by ultrasonication and stirring. Then adjust the pH, add deionized water and stir. Continue to mature to obtain the compound modified solution.

2. The hydrophobic and oleophilic magnetic fluff for oil-water separation according to claim 1, characterized in that, In step a1, the ratio of trifluoropropylmethylcyclotrisiloxane, anhydrous tetrahydrofuran, n-butyllithium-n-hexane solution, dimethylchlorosilane, n-hexane, and anhydrous sodium sulfate is 11.7-19.5 g : 10-16.7 mL : 10-16.7 mL : 2.99-4.99 mL : 30-50 mL : 5-6.6 g; the concentration of the n-butyllithium-n-hexane solution is 2.5 mol / L.

3. The hydrophobic and oleophilic magnetic fluff for oil-water separation according to claim 1, characterized in that, The ratio of anhydrous toluene, vinyltrimethoxysilane, platinum(O)-1,3-diethylene-1,1,3,3-tetramethyldisiloxane and hydrogen-containing silane in step a2 is 15-17g: 8.47-9.68g: 7-8μL: 11.68-13.35g.

4. The hydrophobic and oleophilic magnetic fluff for oil-water separation according to claim 1, characterized in that, The ratio of anhydrous ethanol, fluorinated silane, and hexadecyltrimethoxysilane used in step a3 is 200-225 mL. 6.4-7.2g: 1.6-1.8g.

5. The hydrophobic and oleophilic magnetic fluff for oil-water separation according to claim 1, characterized in that, In step a4, the ratio of nano-silica, anhydrous ethanol, and γ-aminopropyltriethoxysilane is 1-2g: 20-40mL: 0.1-0.2mL; the particle size of the nano-silica is 20-50nm.

6. The hydrophobic and oleophilic magnetic fluff for oil-water separation according to claim 1, characterized in that, The ratio of the modified nano-silica, silane compound solution and deionized water used in step a5 is 0.8-0.9g: 200-225mL: 0.2-0.225mL.

7. A method for preparing hydrophobic and oleophilic magnetic fibers for oil-water separation, characterized in that, The method for preparing a hydrophobic and oleophilic magnetic villous material for oil-water separation as described in any one of claims 1-6 comprises the following steps: Step 1: Weigh out 12-15 parts of the base material, 1-2 parts of the magnetite magnetic particles, 250-300 parts of distilled water, 0.01-0.03 parts of polyvinylpyrrolidone, and 200-220 parts of the compounded modification solution according to the following weight proportions, and set aside for later use; Step 2: Clean the substrate, then dry it, loosen it, and obtain the pre-treated recycled yarn; Step 3: Add the magnetic particles of iron oxide to distilled water, add polyvinylpyrrolidone, and disperse by ultrasonication. Then, immerse the pretreated recycled fibers in the dispersion, stir and adsorb, remove the recycled fibers, squeeze and dry to obtain magnetic fluff. Step 4: Add the magnetic fluff to an industrial-grade 316L stainless steel reactor, pour in the compound modification solution, stir to react, wash, and dry to obtain hydrophobic and oleophilic magnetic fluff.

8. The method for preparing hydrophobic and oleophilic magnetic fibers for oil-water separation according to claim 7, characterized in that, The substrate in step one is made of cashmere or wool yarn recycled, with a fiber diameter of 10-30μm and a length of 5-20mm; the magnetic particles of iron oxide have a particle size of 50-200nm; and the CAS number of the polyvinylpyrrolidone is 9003-39-8.

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