Composite oil-absorbing fiber membrane, its preparation method and application

Abstract

This invention relates to the field of oily wastewater treatment technology, specifically a composite oil-absorbing fiber membrane, its preparation method, and its application. The preparation method comprises the following steps: First, modified soapstone-based ternary copolymer resin is obtained by reacting modified soapstone, styrene, methyl methacrylate, divinylbenzene, and an initiator under an inert gas atmosphere. Second, a blend material is obtained by uniformly mixing a required amount of polymer material and the modified soapstone-based ternary copolymer resin, wherein the mass ratio of the modified soapstone-based ternary copolymer resin to the polymer material is 0.9% to 1.9%. Third, the blend material is processed into a fiber film using a melt-blown extrusion process, thus obtaining the composite oil-absorbing fiber membrane. The composite oil-absorbing fiber membrane of this invention exhibits excellent hydrophobic and oleophilic properties, effectively overcomes the problem of difficult resin recovery, and improves the recyclability of the composite oil-absorbing fiber membrane in practical applications.

Description

Technical Field

[0001] This invention relates to the field of oily wastewater treatment technology, specifically a composite oil-absorbing fiber membrane, its preparation method, and its application. Background Technology

[0002] Compared to the traditional petrochemical industry, the coal chemical industry, which started later but developed rapidly, is a response to my country's current resource situation of "abundant coal, scarce oil, and poor gas." Furthermore, the strategic position of abundant coal resources as my country's primary energy source is unlikely to change in the short term. Coal chemical enterprises use coal as a basic raw material, transforming it into different forms of fuels and chemical products through chemical processing. The water used in the washing, condensation, and purification processes during thermal and catalytic processing constitutes coal chemical wastewater. Traditional coal chemical processes include coking, coal gasification, and liquefaction. While these processes supply numerous energy fuels and chemical products, they also generate highly destructive pollutants such as high concentrations of COD, phenols, cyanides, oil, ammonia nitrogen, and large amounts of recalcitrant organic matter. Under the dual-carbon context, developing a clean and environmentally friendly coal chemical industry with the goal of producing clean energy and petrochemical alternatives has become an important development direction. Although new coal chemical technologies are developing steadily, environmental pollution problems still fall far short of environmental protection requirements. High pollution levels, difficulty in wastewater treatment, and high costs remain bottlenecks for the development of the coal chemical industry. The production of new coal chemical products such as coal-to-oil, coal-to-olefins, and coal-to-alcohol ethers requires a large amount of makeup water. However, the utilization of this makeup water also generates a wide variety of wastewater with large volumes and complex compositions, including cooling wastewater, desalination wastewater, purification wastewater, circulating sewage, and equipment drainage. This further increases the difficulty and cost of treating coal chemical wastewater. Some companies, in an effort to save costs, continue to reuse the wastewater without treatment. After recycling, the suspended solids content in the water continues to rise, and the pollution concentration due to the mixture of different components seriously exceeds the standards. Traditional methods are insufficient to completely treat this wastewater, making the search for harmless treatment and compliant discharge of wastewater particularly important. Typically, the concentration of oil in wastewater hinders biological treatment, requiring it to be below 50 mg / L during biological treatment. This also indicates that if the oil content is not reduced during pretreatment, it will clog pipes and equipment, increasing the difficulty of treatment, and will severely inhibit the activity of microorganisms during biological treatment, reducing the treatment effect. Based on the size of the oil droplets, oils can be classified into the following physical states: floating oil, dispersed oil, emulsified oil, dissolved oil, and solids. Therefore, the removal of oily substances is a primary problem to be solved. Currently, the treatment process for oily substances in wastewater can be divided into physical, chemical, physicochemical, and biological methods. Zhao Qingliang et al. (Zhao Qingliang, Guan Fengwei. Study on the treatment of biological effluent from coal gasification wastewater with different coagulants [J]. Journal of Natural Science of Heilongjiang University, 2010, 27(2):233-236.) used coagulation to treat the biochemical effluent from coal gasification wastewater. The selected coagulants were aluminum sulfate, polyaluminum chloride, polyferric sulfate, and ferric chloride. The results showed that polyferric sulfate (PFS) was used as a coagulant, but it is harmful to the environment and has a high treatment cost, making it difficult for most enterprises to apply industrially.Hu Lei et al. (Hu Lei, Zhao Dachuan, Yang Houling, et al. Research on deep treatment and regeneration of coking wastewater with powdered activated carbon [J]. Environmental Protection Technology, 2016, 22(1):41-44) used activated carbon for adsorption treatment of biochemical + Fenton effluent from coking wastewater. Under the conditions of adding 20 g / L of powdered activated carbon, adjusting the adsorption temperature to 20 degrees Celsius, and controlling the adsorption reaction time to 30 minutes, the COD removal rate was 53.73%, and the COD of the treated wastewater was 57.68 mg / L. However, the adsorption performance of activated carbon was poor and it could not be reused effectively. Meng Lingdong et al. (Meng Lingdong, Zheng Hongwei, Wu Xina, et al. Preparation and performance study of composite coating based on acrylate super oil-absorbing resin [J]. China Coatings, 2021, 36(6):24-28.) synthesized an acrylate super oil-absorbing resin by suspension polymerization of hexadecyl methylpropionate, butyl acrylate and styrene, and investigated the effect of different ratios of the three monomers on the oil absorption ratio of the oil-absorbing resin. The results showed that when the ratio of styrene, hexadecyl methylpropionate and butyl acrylate was 1:10:1, the oil absorption ratio of the oil-absorbing resin for diesel oil reached a maximum of 14.36 g / g, and the absorption ratios for gasoline and aviation kerosene were 13.66 g / g and 12.10 g / g, respectively. However, most of the resin was in the form of powder and small particles, which was not conducive to recycling and had poor recyclability. Jian Zhongbao (Jian Zhongbao. Synthesis of Functionalized Polyolefins: From Catalyst to Polar Monomer Design [J]. Acta Polymerica Sinica, 2018(11):1359-1371.) prepared meltblown nonwoven materials for oil absorption using polypropylene (PP) and poly(butyl methacrylate-co-methyl methacrylate) as raw materials. The resulting blended meltblown nonwoven materials have rough surfaces and dotted protrusions, making the fibers easier to wet with oil. They have good hydrophobicity and superoleophilicity, with contact angles to water and toluene greater than 127° and about 0°, respectively. The oil absorption of diesel, toluene, and xylene can be increased to 7 g / g to 10 g / g. Although its hydrophobic and oil absorption properties have been improved, its recycling performance is poor and its recycling rate is low. Lee (Chen L, Lai J, Li M, et al. Long-lived T-thaped micropillars with submicron-villi on PP / POE surfaces with grinding-enhanced water repellency fabricated via hot compression molding[J]. J Phys Chem B, 2021, 125(26): 7290-7298.) et al. used needle punching technology to blend polypropylene short fibers and kapok to prepare blended nonwoven materials with different mass ratios for oil absorption.Although the above oil-absorbing resins have good oil absorption properties, they are difficult to recycle in actual wastewater applications and can easily cause secondary pollution to the environment. Pure polypropylene meltblown fiber membranes have poor oil absorption properties. Summary of the Invention

[0003] This invention provides a composite oil-absorbing fiber membrane, its preparation method, and its application, overcoming the shortcomings of the prior art. It can effectively solve the problems of low oil absorption, difficulty in recovery, and poor recovery performance of existing adsorption materials.

[0004] One of the technical solutions of the present invention is achieved through the following measures: a method for preparing a composite oil-absorbing fiber membrane, comprising the following steps:

[0005] The first step involves reacting modified soapstone, styrene, methyl methacrylate, divinylbenzene, and an initiator under an inert gas atmosphere to obtain a modified soapstone-based terpolymer resin.

[0006] The second step involves mixing the required amount of polymeric material and modified saponite-based ternary copolymer resin evenly to obtain a blended material, wherein the mass ratio of modified saponite-based ternary copolymer resin to polymeric material is 0.9% to 1.9%.

[0007] The third step involves processing the blended material into a fiber film using a meltblown-extrusion process, thus obtaining a composite oil-absorbing fiber film.

[0008] The following are further optimizations and / or improvements to the above-mentioned technical solution:

[0009] The specific operation of the first step above is as follows: add the required amount of solvent, modified soapstone, styrene, methyl methacrylate, divinylbenzene and initiator to the reactor, disperse by ultrasonication, stir and react under inert gas protection, and wash and dry the reaction product to obtain the modified soapstone-based terpolymer resin.

[0010] In the first step above, the volume ratio of styrene to methyl methacrylate is 2:6 to 6:2, and the amount of divinylbenzene used is 20% to 30% of the total volume of styrene and methyl methacrylate.

[0011] In the first step above, the modified soapstone is obtained by modifying purified soapstone with a modifier, wherein the modifier is one of diallyl dimethyl ammonium chloride, diallyl diethyl ammonium chloride, and diallyl trimethyl ammonium chloride; the amount of modified soapstone used is 9% to 12% of the total mass of styrene, methyl methacrylate, and divinylbenzene.

[0012] In the first step above, the solvent is a mixture of N,N-dimethylformamide and acetonitrile in a volume ratio of 1:7 to 3:5, and the amount of solvent used is 5 to 10 times the total amount of styrene, methyl methacrylate, and divinylbenzene.

[0013] In the first step above, the initiator is azobisisobutyronitrile, a type of benzoyl peroxide, and the mass-volume ratio of the initiator to the total volume of styrene, methyl methacrylate, and divinylbenzene is 0.2 g to 0.5 g: 50 ml.

[0014] In the first step above, the reaction temperature under inert gas protection is 80 to 85 degrees Celsius, and the reaction time is 6 to 8 hours.

[0015] In the third step of the above-mentioned meltblown-extrusion process, the meltblown temperature is 275 degrees Celsius to 285 degrees Celsius, the meltblown pressure is 280 kPa to 290 kPa, the extrusion temperature is 280 degrees Celsius to 290 degrees Celsius, and the extrusion pressure is 425 kPa to 435 kPa.

[0016] In the second step above, the polymer material is polypropylene particles or polylactic acid particles.

[0017] In the third step above, the average fiber diameter of the composite oil-absorbing fiber membrane is 0.5 micrometers to 10 micrometers, the porosity is greater than or equal to 85%, and the areal density is 3 mg / cm² to 150 mg / cm².

[0018] The second technical solution of the present invention is achieved by the following measures: a composite oil-absorbing fiber membrane prepared by a method for preparing a composite oil-absorbing fiber membrane.

[0019] The third technical solution of the present invention is achieved through the following measures: the application of a composite oil-absorbing fiber membrane in the treatment of oily wastewater, wherein the amount of composite oil-absorbing fiber membrane used per liter of oily wastewater is 6 to 10 grams.

[0020] This invention utilizes a modified soapstone-based ternary copolymer resin and polymer materials to produce a composite oil-absorbing fiber membrane via melt-blowing, exhibiting excellent hydrophobic and oleophilic properties. Simultaneously, it effectively overcomes the problem of difficult resin recycling, improves the recyclability of the composite oil-absorbing fiber membrane in practical applications, and avoids secondary pollution to the environment. Attached Figure Description

[0021] Appendix Figure 1 The infrared spectrum of the modified saponite-based terpolymer resin in Example 12 of this invention is shown.

[0022] Appendix Figure 2 This is a schematic diagram of the contact angle of the composite oil-absorbing fiber membrane in Embodiment 12 and Embodiments 15 to 18 of the present invention.

[0023] Appendix Figure 3 This is a schematic diagram of the contact angles of soapstone, modified soapstone, and modified soapstone-based terpolymer resin in Example 12 of the present invention. Detailed Implementation

[0024] This invention is not limited to the following embodiments, and specific implementation methods can be determined according to the technical solution of this invention and the actual situation. Unless otherwise specified, all chemical reagents and chemicals mentioned in this invention are chemical reagents and chemicals known and commonly used in the prior art; unless otherwise specified, all percentages in this invention are mass percentages; unless otherwise specified, all solutions in this invention are aqueous solutions with water as the solvent, for example, hydrochloric acid solution is an aqueous solution of hydrochloric acid; room temperature in this invention generally refers to a temperature between 15 degrees Celsius and 25 degrees Celsius, generally defined as 25 degrees Celsius.

[0025] The present invention will be further described below with reference to embodiments:

[0026] Example 1: The preparation method of this composite oil-absorbing fiber membrane is carried out according to the following steps:

[0027] The first step involves reacting modified soapstone, styrene, methyl methacrylate, divinylbenzene, and an initiator under an inert gas atmosphere to obtain a modified soapstone-based terpolymer resin.

[0028] The second step involves mixing the required amount of polymeric material and modified saponite-based ternary copolymer resin evenly to obtain a blended material, wherein the mass ratio of modified saponite-based ternary copolymer resin to polymeric material is 0.9% to 1.9%.

[0029] The third step involves processing the blended material into a fiber film using a meltblown-extrusion process, thus obtaining a composite oil-absorbing fiber film.

[0030] This invention utilizes a modified soapstone-based ternary copolymer resin and polymer materials to prepare a composite oil-absorbing material via a melt-blown extrusion process. The modified soapstone-based ternary copolymer resin and polymer materials are mixed in a specific mass ratio. Using a melt-blown machine, the mixture is melted after mixing and heating. The melt is then extruded through a meltblown head and stretched into fine filaments under high temperature and high-speed airflow. After cooling, a composite oil-absorbing fiber film is formed on a roller.

[0031] Example 2: As an optimization of the above example, the specific operation of the first step is as follows: Add the required amounts of solvent, modified soapstone, styrene, methyl methacrylate, divinylbenzene, and initiator to the reactor. After ultrasonic dispersion, stir the reaction under inert gas protection. The resulting reaction product is washed and dried to obtain the modified soapstone-based terpolymer resin. Specifically, the inert gas can be nitrogen, argon, or helium. The reaction product can be washed with methanol, dichloromethane, or acetone. After washing, the reaction product is dried at 65°C to 75°C for 8 to 10 hours.

[0032] Example 3: As an optimization of the above example, in the first step, the volume ratio of styrene to methyl methacrylate is 2:6 to 6:2, and the amount of divinylbenzene used is 20% to 30% of the total volume of styrene and methyl methacrylate.

[0033] Example 4: As an optimization of the above example, in the first step, the modified soapstone is obtained by modifying purified soapstone with a modifier, wherein the modifier is one of diallyl dimethyl ammonium chloride, diallyl diethyl ammonium chloride, and diallyl trimethyl ammonium chloride; the amount of modified soapstone used is 9% to 12% of the total mass of styrene, methyl methacrylate, and divinylbenzene.

[0034] Specifically, the preparation process of modified soapstone is as follows: Take 3 to 5 grams of pure soapstone, stir it in deionized water, let it stand for a certain time, wash and dry it to obtain purified soapstone; disperse the purified soapstone ultrasonically in deionized water, add 6 to 8 grams of modifier, stir and react at 80 to 90 degrees Celsius for 8 to 10 hours, then filter and wash the reaction product, and dry it at 60 to 70 degrees Celsius for 5 to 6 hours to obtain modified soapstone.

[0035] Example 5: As an optimization of the above example, in the first step, the solvent is a mixture of N,N-dimethylformamide and acetonitrile with a volume ratio of 1:7 to 3:5, and the amount of solvent used is 5 to 10 times the total amount of styrene, methyl methacrylate and divinylbenzene.

[0036] Example 6: As an optimization of the above example, in the first step, the initiator is azobisisobutyronitrile, a type of benzoyl peroxide, and the mass-volume ratio of the initiator to the total volume of styrene, methyl methacrylate, and divinylbenzene is 0.2 g to 0.5 g: 50 ml.

[0037] Example 7: As an optimization of the above example, in the first step, the reaction temperature under inert gas protection is 80 degrees Celsius to 85 degrees Celsius, and the reaction time is 6 hours to 8 hours.

[0038] Example 8: As an optimization of the above example, in the second step, the polymer material is polypropylene particles or polylactic acid particles.

[0039] Example 9: As an optimization of the above example, in the third step of the meltblown-extrusion process, the meltblown temperature is 275 degrees Celsius to 285 degrees Celsius, the meltblown pressure is 280 kPa to 290 kPa, the extrusion temperature is 280 degrees Celsius to 290 degrees Celsius, and the extrusion pressure is 425 kPa to 435 kPa.

[0040] Example 10: As an optimization of the above example, in the third step, the average fiber diameter of the composite oil-absorbing fiber membrane is 0.5 micrometers to 10 micrometers, the porosity is greater than or equal to 85%, and the areal density is 3 mg / cm² to 150 mg / cm².

[0041] This invention utilizes modified soapstone to synthesize a modified soapstone-based ternary copolymer resin, which is then compounded with polymer materials to obtain a blended material. The modified soapstone is treated with diallyldimethylammonium chloride and other modifiers to provide double bond groups to the modified soapstone-based ternary copolymer resin, enabling it to participate in the free radical polymerization reaction of styrene, methyl methacrylate, and divinylbenzene, thus obtaining the modified soapstone-based ternary copolymer resin. After uniformly blending the modified soapstone-based ternary copolymer resin with pure polypropylene particles or polylactic acid particles, a composite oil-absorbing fiber membrane is prepared through a melt-blown extrusion process. This effectively improves the hydrophobic and oleophilic properties of the fiber membrane, and the composite oil-absorbing fiber membrane retains excellent reusability even after multiple oil absorption cycles.

[0042] Example 11: Application of the composite oil-absorbing fiber membrane in the treatment of oily wastewater. When treating oily wastewater, the amount of composite oil-absorbing fiber membrane used per liter of oily wastewater is 6 to 10 grams.

[0043] Example 12: This composite oil-absorbing fiber membrane was prepared according to the following steps:

[0044] The first step involves adding the required amounts of solvent, modified soapstone, styrene, methyl methacrylate, divinylbenzene, and initiator to a reactor. After ultrasonic dispersion, the mixture is stirred and reacted for 7 hours at 85 degrees Celsius under nitrogen protection. The resulting reaction products are washed and dried with acetone and methanol, respectively, to obtain the modified soapstone-based terpolymer resin. The amount of modified soapstone used is 5.5 g, styrene is 20 mL, methyl methacrylate is 20 mL, and divinylbenzene is 10 mL. The solvent is a mixture of N,N-dimethylformamide and acetonitrile in a volume ratio of 2:5, and the amount of solvent used is 300 mL. The initiator is azobisisobutyronitrile, and the amount of initiator used is 0.35 g.

[0045] The second step involves mixing 200 grams of polypropylene granules and 2.6 grams of modified soapstone-based ternary copolymer resin evenly to obtain a blended material.

[0046] The third step involves preparing a meltblown composite oil-absorbing fiber membrane from the blended material using a meltblown-extrusion process, resulting in a composite oil-absorbing fiber membrane with an average fiber diameter of 1 micrometer. The meltblown temperature is 280 degrees Celsius, the meltblown pressure is 285 kPa, the extrusion pressure is 430 kPa, and the extrusion temperature is 285 degrees Celsius.

[0047] In this embodiment, the modified soapstone is obtained by modifying purified soapstone with diallyl dimethyl ammonium chloride. The specific operation is as follows: 4 grams of pure soapstone are taken and stirred in deionized water, then left to stand for 8 to 10 hours, washed and dried to obtain purified soapstone; the purified soapstone is ultrasonically dispersed in deionized water, 8 grams of diallyl dimethyl ammonium chloride are added, and the mixture is stirred at 80 degrees Celsius for 8 hours. After that, the reaction product is filtered, washed, and dried at 70 degrees Celsius for 5 hours to obtain modified soapstone.

[0048] Example 13: This composite oil-absorbing fiber membrane was prepared according to the following steps:

[0049] In the first step, the required amounts of solvent, modified soapstone, styrene, methyl methacrylate, divinylbenzene, and initiator are added to a reactor. After ultrasonic dispersion, the mixture is stirred and reacted at 80 degrees Celsius for 8 hours under nitrogen protection. The resulting reaction product is washed and dried with methanol to obtain the modified soapstone-based terpolymer resin. In the first step, the amount of modified soapstone (prepared in the same way as in Example 12) is 5 grams, the amount of styrene is 25 ml, the amount of methyl methacrylate is 15 ml, and the amount of divinylbenzene is 10 ml. The solvent is a mixture of N,N-dimethylformamide and acetonitrile in a volume ratio of 2:5, and the amount of solvent is 400 ml. The initiator is azobisisobutyronitrile, and the amount of initiator is 0.40 grams.

[0050] The second step involves mixing 300 grams of polypropylene granules and 4.5 grams of modified soapstone-based ternary copolymer resin evenly to obtain a blended material.

[0051] The third step involves preparing a meltblown composite oil-absorbing fiber membrane from the blended material using a meltblown-extrusion process, resulting in a composite oil-absorbing fiber membrane with an average fiber diameter of 2 micrometers. The meltblown temperature is 285 degrees Celsius, the meltblown pressure is 290 kPa, the extrusion pressure is 425 kPa, and the extrusion temperature is 280 degrees Celsius.

[0052] Example 14: This composite oil-absorbing fiber membrane was prepared according to the following steps:

[0053] The first step involves adding the required amounts of solvent, modified soapstone, styrene, methyl methacrylate, divinylbenzene, and initiator to a reactor. After ultrasonic dispersion, the mixture is stirred and reacted at 85 degrees Celsius for 6 hours under nitrogen protection. The resulting reaction product is washed and dried with dichloromethane to obtain the modified soapstone-based terpolymer resin. The amount of modified soapstone used is 4.5 g, styrene is 30 mL, methyl methacrylate is 10 mL, and divinylbenzene is 10 mL. The solvent is a mixture of N,N-dimethylformamide and acetonitrile in a volume ratio of 2:5, and the amount of solvent used is 500 mL. The initiator is azobisisobutyronitrile, and the amount of initiator used is 0.45 g.

[0054] The second step involves mixing 300 grams of polylactic acid granules and 4 grams of modified soapstone-based ternary copolymer resin evenly to obtain a blended material.

[0055] The third step involves preparing a meltblown composite oil-absorbing fiber membrane from the blended material using a meltblown-extrusion process, resulting in a composite oil-absorbing fiber membrane with an average fiber diameter of 3 micrometers. The meltblown temperature is 285 degrees Celsius, the meltblown pressure is 290 kPa, the extrusion pressure is 425 kPa, and the extrusion temperature is 280 degrees Celsius.

[0056] In this embodiment, the modified soapstone is obtained by modifying purified soapstone with diallyltrimethylammonium chloride. The specific operation is as follows: 5 grams of pure soapstone are taken and stirred in deionized water, then left to stand for 10 hours, washed and dried to obtain purified soapstone; the purified soapstone is ultrasonically dispersed in deionized water, 8 grams of diallyltrimethylammonium chloride are added, and the mixture is stirred and reacted at 80 to 90 degrees Celsius for 8 hours. After that, the reaction product is filtered, washed, and dried at 70 degrees Celsius for 5 hours to obtain modified soapstone.

[0057] Example 15: The difference from Example 1 is that in the second step, the polypropylene particles are 200 grams and the modified soapstone-based terpolymer resin is 2.8 grams, that is, the mass ratio of the modified soapstone-based terpolymer resin to the polymer material is 1.4%.

[0058] Example 16: The difference from Example 1 is that in the second step, the polypropylene particles are 200 grams and the modified soapstone-based terpolymer resin is 3.0 grams, that is, the mass ratio of the modified soapstone-based terpolymer resin to the polymer material is 1.5%.

[0059] Example 17: The difference from Example 1 is that in the second step, the polypropylene particles are 200 grams, the modified saponite-based terpolymer resin is 3.4 grams, and the mass ratio of the modified saponite-based terpolymer resin to the polymer material is 1.7%.

[0060] Example 18: The difference from Example 1 is that in the second step, the polypropylene particles are 200 grams and the modified soapstone-based terpolymer resin is 3.8 grams, that is, the mass ratio of the modified soapstone-based terpolymer resin to the polymer material is 1.9%.

[0061] Comparative Example 1: Polypropylene fiber membrane meltblown from pure polypropylene particles.

[0062] Comparative Example 2: The fiber membrane differs from Example 1 in that the modified soapstone-based ternary copolymer resin is replaced by a resin reacted with styrene, methyl methacrylate, divinylbenzene and an initiator under an inert gas atmosphere during preparation. In other words, no modified soapstone is added in the first step of the method.

[0063] Oil absorption performance test:

[0064] 30 g, 40 g, and 50 g of the composite oil-absorbing fiber membranes from Examples 12 to 15 and the fiber membranes from Comparative Examples 1 and 2 were added to 5 liters of coal chemical phenol-ammonia oily wastewater, respectively, and the mixtures were allowed to stand for 5 hours for comparative testing. The oil content in the coal chemical phenol-ammonia wastewater before and after the addition of the fiber membranes was determined according to HJ 970-2018 (ultraviolet spectrophotometry), and the results are shown in Table 1.

[0065] The composite oil-absorbing fiber membranes from Examples 12 to 15 and Comparative Examples 1 and 2 used in the third group of experiments in Table 1 were washed with 100 ml (washing volume) of petroleum ether and anhydrous ethanol, and then dried in a vacuum drying oven at 60 degrees Celsius. The dried fiber membranes were added to the coal chemical phenol-ammonia wastewater at a dosage of 10 g / L, and the change in oil content in the wastewater was tested after standing for 5 hours. Subsequently, the fiber membranes were washed and their oil absorption performance was repeatedly tested. The results are shown in Table 2.

[0066] As can be seen from the data in Tables 1 and 2, the composite oil-absorbing fiber membrane of the present invention has better oil-water separation performance than the pure polypropylene fiber membrane, reaching a maximum oil-water separation performance of 80%, and has good reusability. After four uses, it can still achieve an oil-water separation performance of 73%, which is much higher than the oil removal rate of 14% of the pure polypropylene fiber membrane.

[0067] Infrared and contact angle tests:

[0068] The Fourier transform infrared spectrum of the modified soapstone-based ternary copolymer resin synthesized in the first step of the preparation process in Example 12 of this invention was measured using a Thermo Scientific Nicolet Is 50 spectrometer. The sample was thoroughly ground with spectral-grade KBr, then compressed into tablets using a tablet press. The resulting sample was placed in a sample chamber at 4000 cm⁻¹. -1 Up to 500cm -1 The infrared spectrum was obtained below, see Figure 1 . Figure 1 Middle, 1730cm -1 The absorption peak at 1603 cm⁻¹ is the stretching vibration absorption peak of C=O, indicating that methyl methacrylate participates in the polymerization and enters the molecular backbone of the modified soapstone-based terpolymer resin; -1 The sharp absorption peak at 3026 cm⁻¹ is a characteristic vibrational absorption peak of the benzene ring skeleton; -1 The absorption peak at 709 cm⁻¹ is due to the asymmetric stretching vibration of the =CH group on the benzene ring. -1 The absorption peak at 1453 cm⁻¹ is due to the asymmetric stretching vibration of the =CH group on the benzene ring, indicating that styrene participated in the polymerization reaction and entered the modified soapstone-based terpolymer resin skeleton; -1 The absorption peak at 2946 cm⁻¹ is a characteristic absorption peak of the methylene group in divinylbenzene, indicating that divinylbenzene participated in the polymerization reaction;-1 The absorption peak appearing at 1106 cm⁻¹ is the absorption peak of the CH stretching vibration in the -CH₃ group. -1 Characteristic peaks of Si-O-Si are present at 3645 cm⁻¹. -1 The peak at this point is the characteristic stretching vibration peak of -OH, indicating that styrene, divinylbenzene, methyl methacrylate, and modified soapstone all participated in the polymerization reaction and entered the resin skeleton.

[0069] The static contact angle of the composite oil-absorbing fiber membranes in Comparative Examples 1, 2, 12, and 15 to 18 was characterized using a contact angle measuring instrument. Three samples were pressed together, and the contact angle was measured three times. The final result was the average of the measured contact angle values. The results are shown in […]. Figure 2 . Figure 2 In Comparative Example 1, the contact angle of the polypropylene meltblown fiber membrane was 127.9°. This is because polypropylene itself has certain hydrophobic and oleophilic properties. Compared with the pure polypropylene meltblown fiber membrane, when 1.3% to 1.5% by mass of modified soapstone-based ternary copolymer resin is added, the maximum contact angle of the composite oil-absorbing fiber membrane of the present invention is 145.6°. Furthermore, the composite oil-absorbing fiber membrane of the present invention (Example 16) is close to the superhydrophobic and superoleophilic materials reported in the literature (SSJia, Texturing commercial epoxy with hierarchical L and porous structure for robust superhydrophobic coatings, Appl Surf Sci. 466(2019) 84-91). This is because the modified soapstone-based ternary copolymer resin has good hydrophobic properties. Figure 3 It can be seen that the contact angle of the modified saponite-based terpolymer resin is 132°, indicating that the modified saponite-based terpolymer resin has good interfacial compatibility with polypropylene, and can increase the surface roughness of the polypropylene fiber membrane, thereby improving its hydrophobic and oleophilic properties. When 1.7% and 1.9% by mass of modified saponite-based terpolymer resin are added, the contact angle decreases. This is mainly because as the mass fraction of modified saponite-based terpolymer resin increases, the melt strength and apparent melt viscosity of the blend increase, while the fluidity decreases, resulting in uneven blending of the modified saponite-based terpolymer resin and pure polypropylene during melt-blowing. In summary, from Figure 2 It can be seen that the addition of modified soapstone-based ternary copolymer resin can enhance the hydrophobic and oleophilic properties of polypropylene meltblown composite oil-absorbing fiber membrane and improve its oil-water separation performance.

[0070] In summary, the composite oil-absorbing fiber membrane produced by melt-blowing modified soapstone-based ternary copolymer resin and polymer materials has excellent oil-water separation performance and can be reused multiple times. It is recyclable, non-toxic, and pollution-free, effectively overcoming the limitations of existing oil-water separation materials that cannot be reused or recycled, significantly improving oil-water separation performance, and without causing secondary environmental pollution.

[0071] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Unnecessary technical features can be added or removed according to actual needs to meet the needs of different situations.

[0072]

Claims

1. A method for preparing a composite oil-absorbing fiber film, characterized by The following steps are taken: In the first step, the modified saponite, styrene, methyl methacrylate, divinylbenzene and initiator are reacted under inert gas protection to obtain a modified saponite-based terpolymer resin; wherein the volume ratio of styrene to methyl methacrylate is 2:6 to 6:2, the amount of divinylbenzene is 20% to 30% of the total volume of styrene and methyl methacrylate, and the amount of modified saponite is 9% to 12% of the total mass of styrene, methyl methacrylate and divinylbenzene; the modified saponite is obtained by modifying the purified saponite with a modifier, and the modifier is one of diallyldimethylammonium chloride, diallyldiethylammonium chloride and diallyltrimethylammonium chloride; In the second step, the required amount of high molecular material and modified saponite-based terpolymer resin are mixed uniformly to obtain a blended material, wherein the mass ratio of the modified saponite-based terpolymer resin to the high molecular material is 0.9% to 1.9%; the high molecular material is polypropylene particles or polylactic acid particles; In the third step, the blended material is made into a fibrous film through a melt-blowing and extrusion process to obtain a composite oil-absorbing fibrous film. The specific operation of the first step is: adding the required amount of solvent, modified saponite, styrene, methyl methacrylate, divinylbenzene and initiator into a reactor, ultrasonic dispersion, stirring reaction under inert gas protection, and then washing and drying the obtained reaction product to obtain the modified saponite-based terpolymer resin.

2. The method for preparing the composite oil-absorbing fiber membrane according to claim 1, characterized in that... In the first step, the solvent is a mixture of N,N-dimethylformamide and acetonitrile in a volume ratio of 1:7 to 3:5, and the amount of solvent is 5 to 10 times the total amount of styrene, methyl methacrylate and divinylbenzene; or / and, in the first step, the initiator is one of azobisisobutyronitrile and dibenzoyl peroxide, and the mass-volume ratio of the amount of initiator to the total volume of styrene, methyl methacrylate and divinylbenzene is 0.2g to 0.5g:50ml.

3. The method of claim 1 or 2, wherein In the first step, the reaction temperature under inert gas protection is 80°C to 85°C, and the reaction time is 6 to 8 hours.

4. The method for preparing the composite oil-absorbing fiber membrane according to claim 1 or 2, characterized in that... In the melt-blowing and extrusion process of the third step, the melt-blowing temperature is 275°C to 285°C, the melt-blowing pressure is 280kPa to 290kPa, the extrusion temperature is 280°C to 290°C, and the extrusion pressure is 425kPa to 435kPa.

5. The method for preparing the composite oil-absorbing fiber membrane according to claim 1, characterized in that... In the third step, the average fiber diameter of the composite oil-absorbing fibrous film is 0.5μm to 10μm, the porosity is greater than or equal to 85%, and the areal density is 3mg / cm2 to 150mg / cm2.

6. A composite oil-absorbing fibrous film prepared by the method of any one of claims 1 to 5.

7. A method of using the composite oil absorbing fiber film according to claim 6, characterized by When treating oil-containing wastewater, the amount of composite oil-absorbing fibrous film used per liter of oil-containing wastewater is 6g to 10g.

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