Anti-emulsification oil pollution separation membrane and preparation method and application thereof

Abstract

This invention discloses an anti-emulsified oil contamination separation membrane, its preparation method, and its applications. The anti-emulsified oil contamination separation membrane comprises a filter substrate, an active coating, and a hydrophilic polymer layer. The active coating is uniformly bonded to the filter substrate, and each molecule or structural unit constituting the active coating has a graftable group, which at least provides a chemical grafting site. The hydrophilic polymer layer comprises a hydrophilic polymer grafted onto the active coating, and the coverage of the hydrophilic polymer layer on the surface of the anti-emulsified oil contamination separation membrane is above 70%. The anti-emulsified oil contamination separation membrane of this invention exhibits excellent anti-fouling performance against emulsified oil in water, and has broad application prospects in many fields such as oil / water separation, wastewater treatment, purification of traditional Chinese medicine oils, and oil recovery.

Description

Technical Field

[0001] This invention belongs to the field of membrane separation technology, specifically relating to an anti-emulsified oil contamination separation membrane, its preparation method, and its application. Background Technology

[0002] Every year, large amounts of oily wastewater are discharged or leaked into the natural aquatic environment from fields such as oil extraction, chemical smelting, leather tanning, metal processing, and daily life, seriously harming ecosystems and exacerbating freshwater scarcity. From the perspectives of environmental, economic, and sustainable human development, the rational and effective treatment of oily wastewater is extremely urgent. Compared with other treatment technologies, membrane separation technology, based on size sieving mechanisms, has significant advantages in treating oily wastewater, including high efficiency, low energy consumption, and no secondary chemical pollution. However, traditional separation membranes, including polymer membranes, ceramic membranes, and metal membranes, are prone to oil adhesion and fouling during the separation of oily wastewater due to their poor hydrophilicity, causing membrane pore blockage and rapid decline in separation efficiency and flux, and even functional loss.

[0003] Currently, introducing hydrophilic materials onto the surface of separation membranes to form a hydrophilic layer, resisting oil adhesion and fouling, is a mature design approach for preparing antifouling separation membranes. Commonly used hydrophilic modification methods include surface coating modification, surface grafting modification, and blending modification. Surface coating modification refers to attaching hydrophilic substances or their precursors to the separation membrane surface through dip coating or spraying, followed by appropriate post-treatment such as drying or calcination to bond the hydrophilic substances to the membrane surface in the form of a coating, thereby achieving hydrophilicity of the separation membrane and improving its antifouling performance. Surface grafting modification utilizes the active reactive sites on the separation membrane surface to graft hydrophilic polymers onto the membrane surface in the form of covalent bonds, thereby improving the hydrophilicity and antifouling performance of the separation membrane. Blending modification involves incorporating hydrophilic materials as additives into the casting solution of the base membrane material, and then preparing a blend membrane of hydrophilic additive / membrane matrix through phase inversion and other film-forming processes, thereby achieving hydrophilic modification of the separation membrane. However, despite the macroscopically observed superhydrophilic, underwater superoleophobic, and oil-fouling-resistant properties of many hydrophilic-modified separation membranes, significant flux degradation still occurs when separating emulsified oily wastewater. The fundamental reason is insufficient coverage of the hydrophilic polymer on the membrane surface, making it difficult to form a high-coverage hydrophilic layer to resist contamination from emulsified oil droplets, especially small-sized ones, in the oily wastewater. Constructing separation membranes resistant to emulsified oil contamination and achieving low flux degradation in the separation of emulsified oily wastewater remains a significant challenge. Summary of the Invention

[0004] The main objective of this invention is to provide an anti-emulsified oil contamination separation membrane, its preparation method, and its application, so as to overcome the problem of poor long-term separation stability of separation membranes in the prior art.

[0005] To achieve the aforementioned objectives, the technical solution adopted by this invention includes:

[0006] This invention provides an anti-emulsified oil contamination separation membrane, comprising a filter membrane substrate, an active coating, and a hydrophilic polymer layer; the active coating is uniformly bonded to the filter membrane substrate, and each molecule and / or structural unit constituting the active coating has a graftable group, which at least provides a chemical grafting site; the hydrophilic polymer layer comprises a hydrophilic polymer grafted onto the active coating, and the hydrophilic polymer layer has a coverage of more than 70% on the surface of the anti-emulsified oil contamination separation membrane.

[0007] This invention also provides a method for preparing an anti-emulsified oil contamination separation membrane, comprising:

[0008] Provide filter membrane substrate;

[0009] An active coating is formed by modifying the filter membrane substrate with a polymer having grafted groups for adhesive and / or adsorbent properties, thereby obtaining a filter membrane substrate modified with an active coating.

[0010] Furthermore, a hydrophilic polymer containing amino functional groups is grafted onto the active coating to form a hydrophilic polymer layer, thereby obtaining an anti-emulsified oil contamination separation membrane.

[0011] The present invention also provides an anti-emulsified oil contamination separation membrane prepared by the aforementioned preparation method.

[0012] This invention also provides the application of the aforementioned antiemulsified oil contamination separation membrane in the fields of oil / water separation, wastewater purification, marine oil spill treatment, traditional Chinese medicine oil purification, or oil recovery.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0014] (1) Each molecule or structural unit in the active coating of the anti-emulsified oil fouling separation membrane provided by the present invention has a graftable group, which can provide sufficient chemical grafting sites to achieve high coverage of hydrophilic polymer grafting on the membrane surface; the hydrophilic polymer with high coverage on the membrane surface forms a high coverage hydrophilic layer in water, which blocks small-sized emulsified oil from contacting and adhering to the membrane surface, thereby making the anti-emulsified oil fouling separation membrane have excellent anti-fouling performance against emulsified oil, and at the same time have excellent stability;

[0015] (2) The anti-emulsified oil contamination separation membrane provided by the present invention has super oleophobic properties and anti-oil contamination performance in water for both low viscosity oil phase systems (gasoline, light diesel oil, kerosene, vegetable oil, etc.) and high viscosity oil phase systems (petroleum, heavy oil, heavy diesel oil, silicone oil, etc.). Moreover, the flux decay rate is less than 20% during the separation of emulsifier-stable oil / water emulsions, and the flux recovery rate is higher than 90% after simple water flushing. It has excellent anti-contamination performance and has broad application prospects in many fields such as oil / water separation, sewage purification, marine oil spill treatment, traditional Chinese medicine oil purification, and oil recovery. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a cross-sectional scanning electron microscope (SEM) image of the anti-emulsified oil contamination separation membrane in a typical embodiment of the present invention.

[0018] Figure 2a These are the front SEM images and water contact angle test images of the PVDF ultrafiltration membrane in Example 1;

[0019] Figure 2b These are the front SEM images and water contact angle test images of the polyprotocatechuic acid-coated PVDF ultrafiltration membrane in Example 1.

[0020] Figure 2c This is a front view (SEM image and water contact angle test image) of the sulfobetaine-type polymer-grafted PVDF ultrafiltration membrane in Example 1.

[0021] Figure 3 These are photographs showing the antifouling performance test results of the water-based antiemulsified oil contamination separation membrane in Example 1 against the impact of soybean oil droplets.

[0022] Figure 4 These are photographs showing the antifouling performance test results of the water-based antiemulsified oil fouling separation membrane against crude oil in Example 1;

[0023] Figure 5 This is a graph showing the flux change during the continuous separation of sodium dodecyl sulfate-stabilized n-hexane / water emulsion using an anti-emulsification oil fouling separation membrane in water in Example 1.

[0024] Figure 6 This is a schematic diagram of the structure of the anti-emulsified oil contamination separation membrane in a typical embodiment of the present invention. Detailed Implementation

[0025] In view of the deficiencies of the prior art, the inventors of this invention, through long-term research and extensive practice, have proposed the technical solution of this invention. It is mainly based on a uniform coating with abundant active grafting sites grafting a high-coverage hydrophilic polymer onto the filter membrane surface, so as to greatly inhibit the adhesion and accumulation of oil droplets, especially small oil droplets, on the membrane surface, and achieve low flux decay and high flux recovery rate in the process of separating oily wastewater.

[0026] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] First, some technical terms used in this invention are explained as follows:

[0028] Separation membrane: A membrane material with selective permeation capability. It can usually be classified into microfiltration membrane, ultrafiltration membrane, nanofiltration membrane, reverse osmosis membrane, pervaporation membrane, ion exchange membrane, etc., according to the separation mechanism and application range.

[0029] Coating: A solid, continuous film obtained by applying paint in a single coat. It is a thin layer applied to a substrate such as metal, fabric, or plastic for purposes such as protection, insulation, and decoration. Paints can be gaseous, liquid, or solid, and the type and state of the paint are usually determined by the substrate to be sprayed.

[0030] Surface grafting: Surface grafting modification is to use active reaction sites on the surface of the separation membrane to bind functional polymers to the membrane surface in the form of covalent bonds, thereby improving the functionality of the separation membrane, such as hydrophilicity.

[0031] Hydration: The reaction process in which water combines with another molecule to form a new molecule. Water molecules add to the unsaturated bonds of the molecule through their hydrogen and hydroxyl groups to form new compounds. The process by which water, in the form of water molecules, combines with the molecules of a substance to form complexes (such as hydrated crystals of salts, hydrates of hydrocarbons, etc.) can also be broadly referred to as hydration. Properties of hydration include water absorption, water retention, wettability, and swelling. The properties of water-bound molecules are mainly determined by the content and strength of hydrophilic groups in the molecule.

[0032] Contact angle: The angle between the tangent to the gas-liquid interface at the point where the gas, liquid, and solid phases meet and the liquid-solid interface, which is a measure of the degree of wetting.

[0033] Adhesion: refers to the ability of one material to adhere to the surface of another material. The adhering material generally refers to a liquid or powdered solid, while the adhered object refers to an object with a certain surface.

[0034] Specifically, as one aspect of the technical solution of the present invention, the antiemulsified oil contamination separation membrane includes a filter membrane base, an active coating, and a hydrophilic polymer layer; the active coating is uniformly bonded to the filter membrane base, and each molecule and / or structural unit constituting the active coating has a graftable group, the graftable group being used to provide at least a chemical grafting site; the hydrophilic polymer layer includes a hydrophilic polymer grafted onto the active coating, and the hydrophilic polymer layer has a coverage of more than 70% on the surface of the antiemulsified oil contamination separation membrane.

[0035] Furthermore, each molecule or structural unit constituting the active coating has a graftable group, providing ample chemical grafting sites.

[0036] In some preferred embodiments, the structural SEM image of the antiemulsified oil contamination separation membrane of the present invention is shown in Figure 1.

[0037] Specifically, the anti-emulsified oil fouling separation membrane of the present invention consists of three parts: a filter membrane base, a uniform active coating modified on the filter membrane, and a high-coverage hydrophilic polymer layer grafted onto the coating. Each molecule or structural unit constituting the active coating has a graftable group, which can provide sufficient chemical grafting sites to achieve high-coverage grafting of the hydrophilic polymer on the membrane surface. The hydrophilic polymer is a homopolymer or copolymer rich in hydroxyl, carboxyl, amino, sulfonic acid, phosphate and quaternary ammonium ions, which forms a high-coverage hydrophilic layer under high coverage conditions, and has low adhesion and anti-fouling properties to small-sized emulsified oil in water.

[0038] In some preferred embodiments, the anti-emulsified oil contamination separation membrane has stable underwater superoleophobic properties and anti-oil contamination function against hexane, gasoline, diesel, kerosene, soybean oil, vacuum pump oil and crude oil.

[0039] In some preferred embodiments, the hydrophilic polymer layer has a coverage of 70-99% on the surface of the antiemulsified oil contamination separation membrane.

[0040] Furthermore, when the hydrophilic polymer is an amino-functionalized sulfobetaine-type polymer, the hydrophilic polymer layer has a coverage rate of 90-99% on the surface of the antiemulsified oil contamination separation membrane.

[0041] In some preferred embodiments, the underwater oil contact angle of the antiemulsified oil contamination separation membrane is greater than 150° and the adhesion force is less than 10 μN.

[0042] In some preferred embodiments, the anti-emulsified oil contamination separation membrane has a flux decay rate of less than 20% in the separation of emulsifier-stabilized oil / water emulsions.

[0043] In some preferred embodiments, the antiemulsified oil-contaminated separation membrane has a water flux recovery rate of more than 90% after simple water flushing.

[0044] In some preferred embodiments, each molecule or structural unit constituting the active coating has a graftable group, providing ample chemical grafting sites.

[0045] In some preferred embodiments, the polymer in the active coating comprises an adhesive and / or adsorbent polymer having grafted groups.

[0046] In some preferred embodiments, the polymer in the active coating includes any one or a combination of two or more of polyprotocatechuic acid, polyprotocatechuic acid, lignin, and waterborne polyurethane, and is not limited thereto.

[0047] In some preferred embodiments, the active coating comprises a polyprotocatechuic acid layer and / or a polyprotocatechuic acid layer.

[0048] Furthermore, each protocatechuic acid and / or high-altitude catechuic acid molecule in the polyprotocatechuic acid layer and / or polyhigh-altitude catechuic acid layer has a carboxyl group.

[0049] In some preferred embodiments, the polymer chain of the hydrophilic polymer containing amino functional groups further includes any one or more hydrophilic groups selected from hydroxyl, carboxyl, amino, sulfonic acid, phosphate, and quaternary ammonium ion groups.

[0050] Furthermore, the hydrophilic polymer containing amino functional groups also includes any one or more polymer segments selected from sulfobetaine-type polymers, phosphate betaine-type polymers, carboxybetaine-type polymers, polyacrylic acid, polyacrylamide, polyethylene glycol, polyvinyl alcohol, polyethyleneimine, and polyvinylpyrrolidone.

[0051] In some preferred embodiments, the filter membrane substrate comprises an organic or inorganic separation membrane having multiple pores with micro- or nano-sized pores.

[0052] Furthermore, the filter membrane substrate includes any one or more composite membranes of polyvinylidene fluoride membrane, polyethersulfone membrane, polypropylene membrane, polycarbonate membrane, polystyrene membrane, polyvinyl chloride membrane, polyethylene terephthalate membrane and ceramic membrane, and is not limited thereto.

[0053] In some preferred embodiments, the thickness of the filter membrane substrate is 50–500 μm.

[0054] In some preferred embodiments, the thickness of the active coating is 20–200 nm.

[0055] In some preferred embodiments, the thickness of the hydrophilic polymer layer is 20–200 nm.

[0056] Another aspect of the present invention provides a method for preparing an anti-emulsified oil contamination separation membrane, comprising:

[0057] Provide filter membrane substrate;

[0058] An active coating is formed by modifying the filter membrane substrate with a polymer having grafted groups for adhesive and / or adsorbent properties, thereby obtaining a filter membrane substrate modified with an active coating.

[0059] Furthermore, a hydrophilic polymer containing amino functional groups is grafted onto the active coating to form a hydrophilic polymer layer, thereby obtaining an anti-emulsified oil contamination separation membrane.

[0060] In some preferred embodiments, the preparation method specifically includes: immersing the filter membrane substrate in a solution of an adhesive and / or adsorbent polymer with grafted groups to obtain a filter membrane substrate modified with an active coating.

[0061] In some preferred embodiments, the preparation method specifically includes: immersing the filter membrane substrate in a solution containing protocatechuic acid and / or high-altitude catechuic acid to obtain a filter membrane substrate modified with an active coating.

[0062] Furthermore, the use of CuCl2 and H2O2 in this invention accelerates the deposition and self-polymerization of protocatechuic acid.

[0063] Furthermore, the adhesive and / or adsorbent polymer with grafted groups includes any one or more combinations of polyprotocatechuic acid, polyprotocatechuic acid, lignin, and waterborne polyurethane, and is not limited thereto.

[0064] Furthermore, the mass concentration of the solution of the adhesive and / or adsorbent polymer with grafted groups is 0.1–100 g / L, and the immersion contact time is 1–48 h.

[0065] Furthermore, the mass concentration of the solution containing protocatechuic acid and / or plateau catechuic acid is 5–20 g / L, and the immersion contact time is 4–12 h.

[0066] In some preferred embodiments, the preparation method specifically includes: placing a filter membrane substrate modified with an active coating in a hydrophilic polymer solution containing amino functional groups and performing a grafting reaction at 20–40°C to obtain an anti-emulsified oil contamination separation membrane.

[0067] Furthermore, the polymer chain of the hydrophilic polymer containing amino functional groups also includes any one or more hydrophilic groups selected from hydroxyl, carboxyl, amino, sulfonic acid, phosphate, and quaternary ammonium ion groups.

[0068] Furthermore, the hydrophilic polymer containing amino functional groups also includes any one or more polymer segments selected from sulfobetaine-type polymers, phosphate betaine-type polymers, carboxybetaine-type polymers, polyacrylic acid, polyacrylamide, polyethylene glycol, polyvinyl alcohol, polyethyleneimine, and polyvinylpyrrolidone.

[0069] Furthermore, the mass concentration of the hydrophilic polymer solution containing amino functional groups is 5–50 g / L, and the grafting reaction time is 4–96 h.

[0070] Furthermore, when the hydrophilic polymer containing amino functional groups is an amino-functionalized sulfobetaine-type polymer, the mass concentration of the solution of the hydrophilic polymer containing amino functional groups is 5–20 g / L, and the grafting reaction time is 12–48 h.

[0071] In some preferred embodiments, when the polymer of the active coating is any one or a combination of two or more of polyprotocatechuic acid, polyprotocatechuic acid, and waterborne polyurethane, the grafting reaction further includes an activator.

[0072] Furthermore, the grafting reaction also includes the solution pH buffer 2-(N-morphine)ethanesulfonic acid.

[0073] Furthermore, the activator is a mixture of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide.

[0074] Furthermore, the mass ratio of the N-hydroxysuccinimide to 1-ethyl-(3-dimethylaminopropyl)carbodiimide is 5:3.

[0075] In this invention, the further grafting reactions of the polyprotocatechuic acid coating, polyprotocatechuic acid coating, and polyurethane coating all require the presence of an activator.

[0076] In some preferred embodiments, the filter membrane substrate comprises an organic or inorganic separation membrane having multiple pores with micro- or nano-sized pores.

[0077] Furthermore, the filter membrane substrate includes any one or more composite membranes of polyvinylidene fluoride membrane, polyethersulfone membrane, polypropylene membrane, polycarbonate membrane, polystyrene membrane, polyvinyl chloride membrane, polyethylene terephthalate membrane and ceramic membrane, and is not limited thereto.

[0078] This invention first modifies the filter membrane with a uniform active coating. Each molecule or structural unit in the active coating has a graftable group, which can provide sufficient chemical grafting sites, thereby achieving a high coverage grafting rate of hydrophilic polymers on the membrane surface. After hydration, the tightly grafted hydrophilic polymers extend on the membrane surface and form a defect-free hydrophilic layer defense barrier, preventing oil droplets, especially small oil droplets, from contaminating the membrane surface, thus obtaining a separation membrane with low flux attenuation properties during oil / water separation.

[0079] In some more specific embodiments, the method for preparing the antiemulsified oil contamination separation membrane includes:

[0080] 1) A filter membrane with micro-nano pore size is immersed in a solution of adhesive or adsorbent polymer with abundant chemically active groups and deposited for a period of time to prepare a filter membrane with a uniform active coating.

[0081] 2) The above-mentioned coated modified filter membrane is immersed in a solution of hydrophilic polymer containing amino functional groups, and activators 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide are added. After reacting for a period of time, a filter membrane grafted with hydrophilic polymer with high surface coverage is prepared.

[0082] Furthermore, the structural schematic diagram of the anti-emulsified oil contamination separation membrane is shown below. Figure 6 As shown, Figure 6 As shown, a uniform coating with abundant grafting sites was applied to the surface of the filter membrane in step 1). In step 2), a high-coverage hydrophilic polymer was grafted onto the coating. This hydrophilic polymer layer can form a dense hydrophilic layer in the hydrated state, resisting the adhesion and accumulation of oil droplets, especially small oil droplets, on the membrane surface during oil / water separation.

[0083] Another aspect of the present invention provides an anti-emulsified oil contamination separation membrane prepared by the aforementioned preparation method.

[0084] Another aspect of the present invention provides the application of the aforementioned anti-emulsified oil contamination separation membrane in the fields of oil / water separation, wastewater purification, marine oil spill treatment, traditional Chinese medicine oil purification, or oil recovery.

[0085] The technical solution of the present invention will be further described in detail below with reference to several preferred embodiments and accompanying drawings. This embodiment is implemented on the premise of the technical solution of the invention, and provides detailed implementation methods and specific operation processes. However, the protection scope of the present invention is not limited to the following embodiments.

[0086] Unless otherwise specified, the experimental materials used in the examples below can be purchased from conventional biochemical reagent companies.

[0087] Example 1

[0088] Commercial PVDF ultrafiltration membrane ( Figure 2a The PVDF membrane was immersed in ethanol and sonicated for approximately 5 minutes. Afterward, the membrane was vertically immersed in 5g of a solution containing 20mM CuCl2 and 160mM H2O2. -1 Protocatechuic acid-coated PVDF membranes were prepared by allowing the mixture to stand in an aqueous solution for 4 hours. Figure 2b Then, the protocatechuic acid-coated PVDF membrane was immersed in a solution containing 1 g / L of... -1 2-(N-morphine) ethanesulfonic acid, 5g L -1 N-hydroxysuccinimide and 3g L -1 20 g L of 1-ethyl-(3-dimethylaminopropyl)carbodiimide -1 The reaction was carried out in an aqueous solution of poly((2-(methacryloyloxy)ethyl)dimethyl-(3-sulfonylpropyl))-co-poly(aminoethyl methacrylate) in a shaker at 40°C. 3 g L of the solution was added to the reaction system every 24 hours. -1 1-Ethyl-(3-dimethylaminopropyl)carbodiimide, after 48 hours, yields an anti-emulsified oil-fouling separation membrane. Figure 1 and Figure 2c The surface coverage of poly((2-(methacryloyloxy)ethyl)dimethyl-(3-sulfonylpropyl))-co-poly(2-aminoethyl methacrylate) on the antiemulsified oil-fouling separation membrane is 92.8%. As a result, the separation membrane exhibits stable underwater superoleophobic properties and anti-oil-fouling function against hexane, gasoline, diesel, kerosene, soybean oil, and crude oil. Figure 3 and Figure 4 Specifically, the underwater oil contact angle is greater than 160°, the adhesion force is less than 1 μN, and the water flux is 800 L / m³ during a 10-hour continuous separation of sodium dodecyl sulfate-stabilized n-hexane / water emulsion. -2 h -1 bar -1 The flux decay rate was 5.1%, and the flux recovery rate after simple water flushing was 99.6%, demonstrating anti-emulsified oil fouling performance. Figure 5 ).

[0089] Example 2

[0090] A commercially available PVDF ultrafiltration membrane was immersed in ethanol and sonicated for approximately 5 minutes. Afterward, the PVDF membrane was vertically immersed in a 10g L solution containing 5mM CuSO4, 20mM H2O2, and 50mM Tris8.5. -1 A plateau catechin-coated PVDF membrane was prepared by allowing the mixture to stand in an aqueous solution for 4 hours. Then, the plateau catechin-coated PVDF membrane was immersed in an aqueous solution containing 1 g / L of... -12-(N-morphine) ethanesulfonic acid, 5g L -1 N-hydroxysuccinimide and 3g L -1 20 g L of 1-ethyl-(3-dimethylaminopropyl)carbodiimide -1 The reaction was carried out in an aqueous solution of poly((2-(methacryloyloxy)ethyl)dimethyl-(3-sulfonylpropyl))-co-poly(aminoethyl methacrylate) in a shaker at 40°C. 3 g L of the solution was added to the reaction system every 24 hours. -1 1-Ethyl-(3-dimethylaminopropyl)carbodiimide was used to obtain an anti-emulsified oil contamination separation membrane after 48 hours. The surface coverage of poly((2-(methacryloyloxy)ethyl)dimethyl-(3-sulfonylpropyl))-co-poly(2-aminoethyl methacrylate) on the anti-emulsified oil contamination separation membrane was 95.2%. As a result, the separation membrane exhibited stable underwater superoleophobic properties and anti-oil contamination function against hexane, gasoline, diesel, kerosene, soybean oil, and crude oil. Specifically, the underwater oil contact angle was greater than 160°, the adhesion force was less than 1 μN, and the water flux was 900 L / m³ during 10 hours of continuous separation of sodium dodecyl sulfate-stabilized aviation kerosene / water emulsion. -2 h -1 bar -1 The flux decay rate was 6.4%, and the flux recovery rate after simple hydraulic flushing was 98.6%, demonstrating anti-emulsified oil contamination performance.

[0091] Example 3

[0092] A commercially available polyethersulfone ultrafiltration membrane was immersed in ethanol and sonicated for approximately 5 minutes. Then, the polyethersulfone membrane was vertically immersed in 20 g / L of a solution containing 20 mM AgNO3 and 160 mM H2O2. -1 A lignin-coated polyethersulfone (PES) membrane was prepared by allowing the lignin-coated PES membrane to stand in an aqueous lignin solution for 4 hours. Then, the PES membrane was immersed in an aqueous solution containing 1 g of lignin. -1 20g L of triethylamine -1 An anti-emulsified oil-contamination separation membrane was prepared by reacting polyacrylamide-co-poly(2-aminoethyl methacrylate) in an aqueous solution at 40°C in a shaker for 48 hours. The surface coverage of the polyacrylamide-co-poly(2-aminoethyl methacrylate) on the anti-emulsified oil-contamination separation membrane was 90.6%. As a result, the separation membrane exhibited stable underwater superoleophobic properties and anti-oil-contamination function against hexane, gasoline, diesel, kerosene, soybean oil, and crude oil, specifically demonstrating an underwater oil contact angle greater than 155°, an adhesion force less than 2 μN, and a water flux of 820 L / m³ during 10 hours of continuous separation of sodium dodecyl sulfate-stabilized hexane / water emulsion. -2 h -1 bar -1The flux decay rate was 9.8%, and the flux recovery rate after simple hydraulic flushing was 96.8%, demonstrating anti-emulsified oil contamination performance.

[0093] Example 4

[0094] A commercially available polypropylene microfiltration membrane with a slightly larger pore size was immersed in ethanol and sonicated for approximately 5 minutes. Then, the polypropylene microfiltration membrane was vertically immersed in a 10g L solution containing 20mM CuCl2 and 160mM H2O2. -1 A protocatechuic acid-coated polypropylene microfiltration membrane was prepared by allowing the reaction to proceed statically in an aqueous solution for 12 hours. Then, the protocatechuic acid-coated polypropylene microfiltration membrane was immersed in a solution containing 1 g / L of... -1 2-(N-morphine) ethanesulfonic acid, 5g L -1 N-hydroxysuccinimide and 3g L -1 20 g L of 1-ethyl-(3-dimethylaminopropyl)carbodiimide -1 The reaction was carried out in an aqueous solution of poly((2-(methacryloyloxy)ethyl)dimethyl-(3-sulfonylpropyl))-co-poly(aminoethyl methacrylate) in a shaker at 40°C. 3 g / L of the solution was added to the reaction system every 24 hours. -1 1-Ethyl-(3-dimethylaminopropyl)carbodiimide was used to obtain an anti-emulsified oil-fouling separation membrane after 48 hours. The surface coverage of poly((2-(methacryloyloxy)ethyl)dimethyl-(3-sulfonylpropyl))-co-poly(2-aminoethyl methacrylate) on the anti-emulsified oil-fouling separation membrane was 95.2%. As a result, the separation membrane exhibited stable underwater superoleophobic properties and anti-oil-fouling function against hexane, gasoline, diesel, kerosene, soybean oil, and crude oil, specifically demonstrating an underwater oil contact angle greater than 160°, an adhesion force less than 1 μN, and a water flux of 2060 L / m³ during 10 hours of continuous separation of sodium dodecyl sulfate-stabilized hexane / water emulsion. -2 h -1 bar -1 The flux decay rate was 15.6%, and the flux recovery rate after simple hydraulic flushing was 97.6%, demonstrating anti-emulsified oil contamination performance.

[0095] Example 5

[0096] A commercially available polypropylene microfiltration membrane with a slightly larger pore size was immersed in ethanol and sonicated for approximately 5 minutes. Then, the polypropylene microfiltration membrane was vertically immersed in a solution containing 20 g L... -1 A polyurethane-coated polypropylene microfiltration membrane was prepared by standing in an aqueous polyurethane solution for 1 hour, then removing it and air-drying it in a natural environment for 48 hours. The polyurethane-coated polypropylene microfiltration membrane was then immersed in a solution containing 1 g L... -1 2-(N-morphine) ethanesulfonic acid, 5g L -1N-hydroxysuccinimide and 3g L -1 20 g L of 1-ethyl-(3-dimethylaminopropyl)carbodiimide -1 The polymer poly((2-(methacryloyloxy)ethyl)dimethyl-(3-sulfonylpropyl))-co-poly(2-aminoethyl methacrylate) was reacted in an aqueous solution on a shaker at 40°C. 3 g L of the solution was added to the reaction system every 24 hours. -1 1-Ethyl-(3-dimethylaminopropyl)carbodiimide was used to obtain an anti-emulsified oil-fouling separation membrane after 48 hours. The surface coverage of poly((2-(methacryloyloxy)ethyl)dimethyl-(3-sulfonylpropyl))-co-poly(2-aminoethyl methacrylate) on the anti-emulsified oil-fouling separation membrane was 93.5%. As a result, the separation membrane exhibited stable underwater superoleophobic properties and anti-oil-fouling function against hexane, gasoline, diesel, kerosene, soybean oil, and crude oil, specifically demonstrating an underwater oil contact angle greater than 150°, an adhesion force less than 2 μN, and a water flux of 1400 L / m³ during 10 hours of continuous separation of sodium dodecyl sulfate-stabilized hexane / water emulsions. -2 h -1 bar -1 The flux decay rate was 18.2%, and the flux recovery rate after simple hydraulic flushing was 95.8%, demonstrating anti-emulsified oil contamination performance.

[0097] Example 6

[0098] A commercially available polyethersulfone ultrafiltration membrane was immersed in ethanol and sonicated for approximately 5 minutes. Afterward, the polyethersulfone membrane was vertically immersed in a 10 g L solution containing 5 mM CuSO4, 20 mM H2O2, and 50 mM Tris8.5. -1 A polyethersulfone membrane coated with plateau catechin was prepared by allowing the plateau catechin to stand in an aqueous solution for 4 hours. Then, the plateau catechin-coated polyethersulfone membrane was immersed in an aqueous solution containing 1 g / L of... -1 2-(N-morphine) ethanesulfonic acid, 5g L -1 N-hydroxysuccinimide and 3g L -1 20 g L of 1-ethyl-(3-dimethylaminopropyl)carbodiimide -1 The reaction was carried out in an aqueous solution of poly((2-(methacryloyloxy)ethyl)dimethyl-(3-sulfonylpropyl))-co-poly(aminoethyl methacrylate) in a shaker at 40°C. 3 g L of the solution was added to the reaction system every 24 hours. -11-Ethyl-(3-dimethylaminopropyl)carbodiimide was used to obtain an anti-emulsified oil contamination separation membrane after 48 hours. The surface coverage of poly((2-(methacryloyloxy)ethyl)dimethyl-(3-sulfonylpropyl))-co-poly(2-aminoethyl methacrylate) on the anti-emulsified oil contamination separation membrane was 97.2%. As a result, the separation membrane exhibited stable underwater superoleophobic properties and anti-oil contamination function against hexane, gasoline, diesel, kerosene, soybean oil, and crude oil. Specifically, the underwater oil contact angle was greater than 160°, the adhesion force was less than 1 μN, and the water flux was 500 Lm³ during 10 hours of continuous separation of sodium dodecyl sulfate-stabilized aviation kerosene / water emulsion. -2 h -1 bar -1 The flux decay rate was 5.5%, and the flux recovery rate after simple hydraulic flushing was 99.1%, demonstrating anti-emulsified oil contamination performance.

[0099] Example 7

[0100] The commercially available ceramic microfiltration membrane was immersed in water and sonicated for approximately 5 minutes. Then, the ceramic microfiltration membrane was vertically immersed in 10 g L of a solution containing 20 mM AgNO3 and 160 mM H2O2. -1 A lignin-coated ceramic microfiltration membrane was prepared by allowing it to stand in an aqueous lignin solution for 12 hours. Then, the lignin-coated ceramic microfiltration membrane was immersed in an aqueous solution containing 5 g of L... -1 20g L of triethylamine -1 An anti-emulsified oil-contamination separation membrane was prepared by reacting poly((2-(methacryloyloxy)ethyl)dimethyl-(3-sulfonylpropyl))-co-poly(2-aminoethyl methacrylate) in an aqueous solution of poly((2-(methacryloyloxy)ethyl)dimethyl-(3-sulfonylpropyl))-co-poly(2-aminoethyl methacrylate) in a shaker at 40°C for 48 h. The surface coverage of poly((2-(methacryloyloxy)ethyl)dimethyl-(3-sulfonylpropyl))-co-poly(2-aminoethyl methacrylate) on the anti-emulsified oil-contamination separation membrane was 92.6%. As a result, the separation membrane exhibited stable underwater superoleophobic properties and anti-oil-contamination function against hexane, gasoline, diesel, kerosene, soybean oil, and crude oil, specifically demonstrating an underwater oil contact angle greater than 152°, an adhesion force less than 2 μN, and a water flux of approximately 2500 L m⁻¹ during 10 h of continuous separation of sodium dodecyl sulfate-stabilized hexane / water emulsions. 2 h - 1 bar -1 The flux decay rate was 17.8%, and the flux recovery rate after simple hydraulic flushing was 95.7%, demonstrating anti-emulsified oil contamination performance.

[0101] Example 8

[0102] A commercially available PVDF ultrafiltration membrane was immersed in ethanol and sonicated for approximately 5 minutes. Afterward, the PVDF membrane was vertically immersed in a solution containing 20 mM CuCl2, 160 mM H2O2, and 5 g L... -1 Protocatechuic acid and 10g L -1 A composite-coated modified PVDF membrane was prepared by allowing the mixture to stand in a high-altitude catechin aqueous solution for 4 hours. Then, the composite-coated modified PVDF membrane was immersed in a solution containing 1 g L... -1 2-(N-morphine) ethanesulfonic acid, 5g L -1 N-hydroxysuccinimide and 3g L -1 20 g L of 1-ethyl-(3-dimethylaminopropyl)carbodiimide -1 The reaction was carried out in an aqueous solution of poly((2-(methacryloyloxy)ethyl)dimethyl-(3-sulfonylpropyl))-co-poly(aminoethyl methacrylate) in a shaker at 40°C. 3 g L of the solution was added to the reaction system every 24 hours. -1 1-Ethyl-(3-dimethylaminopropyl)carbodiimide was used to obtain an anti-emulsified oil-fouling separation membrane after 48 hours. The surface coverage of poly((2-(methacryloyloxy)ethyl)dimethyl-(3-sulfonylpropyl))-co-poly(2-aminoethyl methacrylate) on the anti-emulsified oil-fouling separation membrane was 98.1%. As a result, the separation membrane exhibited stable underwater superoleophobic properties and anti-oil-fouling function against hexane, gasoline, diesel, kerosene, soybean oil, and crude oil, specifically demonstrating an underwater oil contact angle greater than 160°, an adhesion force less than 1 μN, and a water flux of 750 L / m³ during 10 hours of continuous separation of sodium dodecyl sulfate-stabilized hexane / water emulsion. -2 h -1 bar - 1. The flux decay rate was 3.3%, and the flux recovery rate after simple hydraulic flushing was 97.8%, demonstrating anti-emulsified oil contamination performance.

[0103] Comparative Example 1

[0104] A commercially available PVDF ultrafiltration membrane was immersed in ethanol and sonicated for approximately 5 minutes. Afterward, the PVDF membrane was placed in a plasma treatment apparatus and its surface was thoroughly treated in an oxygen environment for 1 hour, followed by rapid immersion in 20 g L of deoxygenated ethanol. -1 Polyacrylic acid-grafted PVDF membranes were prepared by reacting the membranes in an acrylic acid solution for 4 hours. Then, the polyacrylic acid-coated PVDF membranes were immersed in a solution containing 1 g / L of [amount missing]. -1 2-(N-morphine) ethanesulfonic acid, 5g L -1 N-hydroxysuccinimide and 3g L -1 1-Ethyl-(3-dimethylaminopropyl)carbodiimide, 20 g L -1The reaction mixture of poly((2-(methacryloyloxy)ethyl)dimethyl-(3-sulfonylpropyl))-co-poly(2-aminoethyl methacrylate) was carried out in an aqueous solution on a shaker at 40°C. 3 g L of the solution was added to the reaction mixture every 24 hours. -1 1-Ethyl-(3-dimethylaminopropyl)carbodiimide was used to obtain an anti-emulsified oil contamination separation membrane after 48 hours. The surface coverage of poly((2-(methacryloyloxy)ethyl)dimethyl-(3-sulfonylpropyl))-co-poly(2-aminoethyl methacrylate) on the anti-emulsified oil contamination separation membrane was 41.9%. As a result, the separation membrane exhibited an underwater oil contact angle of approximately 151° and an underwater oil adhesion force of approximately 12 μN for hexane, gasoline, diesel, kerosene, soybean oil, and crude oil. The initial water flux was 755 L / m³ during 10 hours of continuous separation of sodium dodecyl sulfate-stabilized hexane / water emulsions. -2 h -1 bar -1 However, the flux decays rapidly, with a flux decay rate of 56.6%. After simple hydraulic flushing, the flux recovery rate is 80.7%, indicating poor resistance to oil contamination.

[0105] Table 1. Hydrophilic polymer surface coverage and antiemulsified oil contamination performance of the separation membranes obtained in Example 1 and the comparative example.

[0106]

[0107] The difference between Example 1 and Comparative Example 1 is that in Example 1, the active group -COOH was generated on the membrane surface by modifying it with a protocatechuic acid active layer, while in Comparative Example 1, the active group -COOH was generated on the membrane surface by conventional plasma treatment. The subsequent grafting conditions for hydrophilic poly((2-(methacryloyloxy)ethyl)dimethyl-(3-sulfopropyl))-co-poly(2-aminoethyl methacrylate) were exactly the same in both Example 1 and Comparative Example 1. However, the coverage of the hydrophilic polymer on the membrane surface in Example 1 was significantly higher than that in Comparative Example 1. The separation membrane obtained in Example 1 exhibited a significantly lower flux decay rate and a significantly higher flux recovery rate in the separation process of hexane / water emulsions stabilized by sodium dodecyl sulfate, demonstrating better anti-emulsified oil fouling performance. As can be seen from the comparison results shown in Table 1, the separation membrane obtained by the preparation method disclosed in this invention has a higher coverage of hydrophilic polymer on its surface. Therefore, the separation membrane obtained by the preparation method disclosed in this invention exhibits superior anti-emulsified oil fouling performance, which cannot be achieved by separation membranes prepared by other methods.

[0108] In addition, the inventors of this case also conducted experiments with other raw materials, process operations, and process conditions described in this specification, referring to the aforementioned embodiments, and obtained relatively ideal results in all cases.

[0109] It should be understood that the technical solutions of the present invention are not limited to the specific embodiments described above. Any technical modifications made to the technical solutions of the present invention without departing from the spirit and scope of the claims are within the scope of protection of the present invention.

Claims

1. An anti-emulsified oil contaminated separation membrane, characterized by, The anti-emulsified oil pollution separation membrane comprises a filter membrane base membrane, an active coating layer and a hydrophilic polymer layer; the active coating layer is uniformly combined on the filter membrane base membrane; the polymer in the active coating layer comprises a cohesive and / or adsorptive polymer with a grafting group, each molecule or structural unit of the polymer has a graftable group, and the graftable group is used at least for providing a chemical grafting site; the hydrophilic polymer layer comprises a hydrophilic polymer grafted on the active coating layer, the hydrophilic polymer is an amino-functionalized sulfobetaine type polymer, and the coverage of the hydrophilic polymer layer on the surface of the anti-emulsified oil pollution separation membrane is 90-99%; The underwater oil contact angle of the anti-emulsified oil pollution separation membrane is greater than 150°, and the adhesion force is less than 10 µN; The anti-emulsified oil pollution separation membrane has a flux decay rate of less than 20% in the process of separating an emulsifier-stable oil / water emulsion. The anti-emulsified oil pollution separation membrane has a water flux recovery rate of greater than 90% after water flow flushing.

2. The anti-emulsified oil pollution separation membrane according to claim 1, characterized in that: The polymer in the active coating layer comprises any one or a combination of two or more of polyprotocatechuic acid, polyhomoprotocatechuic acid, lignin and aqueous polyurethane.

3. The anti-emulsified oil contamination separation membrane according to claim 1, characterized by: The active coating layer comprises a polyprotocatechuic acid layer and / or a polyhomoprotocatechuic acid layer; each protocatechuic acid and / or homoprotocatechuic acid molecule in the polyprotocatechuic acid layer and / or the polyhomoprotocatechuic acid layer has one carboxyl group.

4. The anti-emulsification oil contamination separation membrane according to claim 1, characterized by: The filter membrane base membrane comprises an organic separation membrane or an inorganic separation membrane with a plurality of filter holes, the filter holes have a micro-nano scale pore size, and the filter membrane base membrane comprises any one or a composite membrane of two or more of a polyvinylidene fluoride membrane, a polyether sulfone membrane, a polypropylene membrane, a polycarbonate membrane, a polystyrene membrane, a polyvinyl chloride membrane, a polyethylene terephthalate membrane and a ceramic membrane.

5. The anti-emulsification oil contamination separation membrane according to claim 1, characterized by: The thickness of the filter membrane base membrane is 50-500 µm; and / or, the thickness of the active coating layer is 20-200 nm; and / or, the thickness of the hydrophilic polymer layer is 20-200 nm.

6. The method for producing an anti-emulsified oil contaminated separation membrane according to any one of claims 1 to 5, wherein The method comprises: providing a filter membrane base membrane; modifying a cohesive and / or adsorptive polymer with a grafting group on the filter membrane base membrane to form an active coating layer, thereby obtaining a filter membrane base membrane modified with the active coating layer; and grafting a hydrophilic polymer containing an amino functional group on the active coating layer to form a hydrophilic polymer layer, thereby obtaining an anti-emulsified oil pollution separation membrane.

7. The production method according to claim 6, characterized by, Specifically, the method comprises: immersing the filter membrane base membrane in a solution of the cohesive and / or adsorptive polymer with a grafting group for sufficient contact, thereby obtaining a filter membrane base membrane modified with the active coating layer.

8. The production method according to claim 6, characterized by, Specifically, the method comprises: The preparation method specifically comprises: immersing the filter membrane base membrane in a solution containing protocatechuic acid and / or homoprotocatechuic acid for sufficient contact, thereby obtaining a filter membrane base membrane modified with the active coating layer.

9. The method of claim 7, wherein: The cohesive and / or adsorptive polymer with a grafting group comprises any one or a combination of two or more of polyprotocatechuic acid, polyhomoprotocatechuic acid, lignin and aqueous polyurethane.

10. The method of claim 7, wherein: The mass concentration of the solution of the adhesion and / or adsorption polymer with a grafting group is 0.1-100 g / L, and the time of the immersion contact is 1-48 h.

11. The method of claim 8, wherein: The mass concentration of the solution containing protocatechuic acid and / or homoprotocatechuic acid is 5-20 g / L, and the time of the immersion contact is 4-12 h.

12. The method of claim 6, wherein, Specifically comprising: The filter membrane base membrane modified with an active coating is placed in a solution of a hydrophilic polymer containing amino functional groups and a grafting reaction is carried out at 20-40 DEG C to obtain an anti-emulsified oil pollution separation membrane.

13. The method of claim 12, wherein: When the hydrophilic polymer containing amino functional groups is an amino-functionalized sulfobetaine type polymer, the mass concentration of the solution of the hydrophilic polymer containing amino functional groups is 5-20 g / L, and the time of the grafting reaction is 12-48 h.

14. The method of claim 6, wherein: When the polymer of the active coating is any one or a combination of two or more of polyprotocatechuic acid, polyhomoprotocatechuic acid and aqueous polyurethane, the grafting reaction further comprises an activator; the activator is a mixture of 1-ethyl-(3-dimethylaminopropyl) carbonyl diimide and N-hydroxysuccinimide.

15. The use of the anti-emulsified oil pollution separation membrane according to any one of claims 1-5 in the field of oil / water separation.

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