A method for constructing a composite wetting structure sponge for continuous treatment of oil-in-water emulsion

Abstract

The present invention discloses a method for constructing a composite wetting structure sponge for continuous treatment of water-in-oil emulsions. The present invention prepares a sponge material MP@MS with a wetting gradient through a one-pot method. Hydrophilic particles can be evenly and effectively loaded on the hydrophobic sponge skeleton. The material is then used to treat the surfactant-stabilized water-in-oil emulsion with the assistance of a continuous oil-water separation device. After continuous long-term treatment, the filtrate can still reach 80% of the water transmittance, demonstrating the material's long-term adsorption and demulsification functions. The method for preparing a sponge material with a wetting gradient according to the present invention is simple and convenient; the processing capacity is long-lasting, and it can achieve continuous oil-water separation of surfactant-stabilized emulsions. It has the potential to process emulsions in large quantities, and provides a reference for the design and development of three-dimensional demulsification materials.

Description

Technical Field

[0001] The invention belongs to the technical field of oily wastewater treatment, and particularly relates to a method for constructing a composite wetting structure sponge for continuously treating oil-in-water emulsion. Background Art

[0002] The extraction, transportation, and storage of oil all carry the risk of oil leakage. Furthermore, industrial processes such as metal smelting, machining, printing and dyeing, organic compound production, and food processing also generate large quantities of oily wastewater. Untreated discharge not only pollutes the environment but also inevitably wastes natural resources. Generally speaking, oil in oily wastewater can be divided into three categories based on droplet size: floating oil (>150 μm), dispersed oil (20-150 μm), and emulsified oil (<20 μm). Although the concentration of emulsified oil droplets in wastewater is not high, in the context of the "dual carbon" initiative, strengthening the construction of a recycling system for emulsified oil is essential, and the recovery of low-quality oil holds research potential. Furthermore, emulsified oil is often stably dispersed in water in the form of a colloid, with small droplet size and the presence of surfactants, making it the most difficult to treat and thus warranting greater attention.

[0003] Current methods for treating emulsions can effectively separate oil from water. However, these methods are limited to water purification, and the resulting oil concentrate still contains a high water content, making it impossible to directly enrich and recover the oil phase. For example, published Chinese invention patent CN 219721912U uses a heating rod to continuously heat the emulsion, evaporating and concentrating it. Publicly published Chinese invention patent CN 116272440A designs and prepares a conductive composite membrane that intercepts emulsified oil droplets in wastewater through "size screening" and "charge effect," achieving oil-water separation. Existing processes for recovering emulsified oil droplets still present certain difficulties and challenges.

[0004] Three-dimensional porous materials, such as sponges, have interconnected cage-like structures and long, interlaced channels, as well as extremely high porosity and specific surface area. This provides a solid structural foundation for high oil adsorption performance and has the potential for oil recovery, making it a research focus in recent years. However, current methods for preparing functional sponge materials are complex and time-consuming, limiting their large-scale application. For example, the disclosed Chinese invention patent CN 116606477A uses a polyurethane sponge as a substrate, which is modified by a two-step continuous coating with polydopamine and graphene oxide. The graphene oxide on the sponge surface is then reduced using a reducing agent to produce a superhydrophobic polyurethane sponge for oil adsorption. The disclosed Chinese invention patent CN 116619504A first acidifies and alkalizes natural wood blocks to produce an elastic wood sponge. Then, it was treated in fluorosilane / pyrrole solution and ferric chloride solution successively to grow superhydrophobic polypyrrole on the surface of the wood sponge. Finally, it was freeze-dried to obtain a polypyrrole-modified wood sponge with superhydrophobic properties, which can effectively adsorb oil pollutants and complete oil-water separation.

[0005] Furthermore, continuous oil-water separation is of great significance in practical applications and has potential applications in large-scale oil recovery. Currently, external force-assisted continuous separation of oil-water mixtures is widely used, enriching the material's application methods and taking a step towards practical application. However, few materials are directly used for the continuous treatment of emulsions. Feng et al. found that when the emulsion volume exceeds 25 mL, the treatment effect will be significantly reduced. Therefore, it can be seen that the continuous treatment of emulsions, especially surfactant-stabilized emulsions, with three-dimensional porous materials remains a challenge. Summary of the Invention

[0006] In response to the above problems, the purpose of the present invention is to construct a composite wetting structure sponge for continuous treatment of water-in-oil emulsions, providing a method that can solve the problem that the preparation of functional sponge materials is complex and difficult to use directly for continuous treatment of emulsions.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A method for constructing a composite wetting structure sponge for continuous treatment of oil-in-water emulsions, comprising the following steps:

[0009] S1: Preparation of sponge substrate: A sponge was selected as the substrate, cut into cylinders, ultrasonically cleaned in ethanol, rinsed three times with deionized water, and then ultrasonically cleaned in deionized water; the sponge was squeezed to remove excess water, and then dried in a vacuum drying oven at 60°C for 2 h to obtain the sponge substrate;

[0010] S2: Using a one-pot method, polyethyleneimine, dopamine, Tris-HCl buffer, magnetic particles, and sponge are placed in a three-necked flask to react to obtain the modified sponge material;

[0011] S3: Remove the sponge from the modification solution and rinse it with deionized water for more than five times until the rinse solution is clear and transparent. Squeeze out excess water and dry it in a vacuum drying oven to a constant weight. After drying, remove the sponge to obtain the finished sponge material MP@MS with a wettability gradient.

[0012] S4: The sponge material MP@MS is fixed in the filter column of the continuous oil-water separation device. Under the action of the peristaltic pump, the emulsion containing the surfactant flows from bottom to top in the filter column. The sponge material MP@MS absorbs oil and filters water to achieve oil-water separation.

[0013] Preferably, the sponge in step S1 can be melamine sponge, polyurethane sponge or polydimethylsiloxane sponge.

[0014] Preferably, in the one-pot method in step S2, the reaction solution is a Tris-HCl buffer solution with a Tris concentration of 0.01 M and a pH of 8.5, the reaction temperature is 30-50° C., the preparation process needs to be stirred at a speed of 200-300 rpm for 6-12 hours, and oxygen needs to be introduced during the entire reaction process.

[0015] Preferably, the key materials and dosages in step S2 are: 2-4 g / L polyethyleneimine, 2-4 g / L dopamine, 2-4 g / L 0.1-10 μm commercial magnetic particles, and a volume of 5-20 cm 3 sponge.

[0016] Preferably, in step S3, the finished sponge material having a wettability gradient is modified so that the magnetic particles have a large number of hydroxyl and amino groups, and the sponge exposes more benzene ring structures; the water contact angle of the magnetic particles is 0 to 15°, and the water contact angle of the modified sponge is 120 to 140°.

[0017] Preferably, in step S3, the sponge structure of the sponge material MP@MS having a wettability gradient is that the hydrophilic magnetic particles are distributed in the nodes of the sponge skeleton in a honeycomb flocculent state, making the surface of the sponge skeleton rough and uneven.

[0018] Preferably, in step S4, the continuous oil-water separation device mainly includes three parts: a peristaltic pump, a filter column, and water transmittance monitoring.

[0019] Preferably, the head end of the continuous oil-water separation device is the emulsion to be treated, and the peristaltic pump drives the directional flow of the emulsion. The flow direction in the filter column is bottom-in and top-out to avoid short-circuiting. The filtrate treated by the filter column flows through the water transmittance monitoring link, and the treated filtrate is collected at the tail end of the device.

[0020] Preferably, the sponge compression ratio of the sponge material MP@MS in the filter column is 25% to 75%; the flow rate of the surfactant-containing emulsion entering the filter column is 5 to 100 mL / h; and the hydraulic retention time of the emulsion is 4 to 15 minutes.

[0021] Preferably, the water transmittance monitoring link can be an ultraviolet spectrophotometer, which monitors the transmittance of the filtrate at a wavelength of 610 nm in real time to analyze the oil-water separation effect of the sponge.

[0022] Preferably, in step S4, the emulsion can be prepared by anionic surfactant, cationic surfactant, and nonionic surfactant, and the surfactant concentration is 50 ppm to 500 ppm.

[0023] Preferably, in step S4, the emulsion oil phase includes dichloromethane, chloroform, carbon tetrachloride, petroleum ether, hexadecane, soybean oil, liquid paraffin, vacuum pump oil and engine oil, etc., the concentration of the oil phase is 1000ppm to 10000ppm, and the oil droplet particle size is 5μm to 15μm.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The present invention uses a one-pot process to prepare a sponge material with a wettability gradient, MP@MS. Hydrophilic particles are uniformly and efficiently loaded onto a hydrophobic sponge skeleton. The material then processes surfactant-stabilized oil-in-water emulsions with the aid of a continuous oil-water separation device. After extended treatment, the filtrate maintains a water transmittance of 80%, demonstrating the material's long-lasting adsorption and demulsification capabilities. The present method for preparing a sponge material with a wettability gradient is simple and convenient; its long-lasting processing capacity allows for continuous oil-water separation of surfactant-stabilized emulsions, potentially enabling large-scale emulsion processing. This provides a valuable insight into the design and development of three-dimensional demulsification materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic flow chart of a method for constructing a composite wetting structure sponge for continuously treating an oil-in-water emulsion, as proposed by the present invention;

[0027] Figure 2 This is a schematic diagram of the composition of a continuous oil-water separation device in a method for constructing a composite wettable structure sponge for continuously treating an oil-in-water emulsion proposed by the present invention;

[0028] Figure 3 is a SEM image of the sponge material with a wettability gradient prepared in Example 1;

[0029] Figure 4 is an infrared spectrum of the magnetic particles modified with DA / PEI in Example 1;

[0030] Figure 5 is the water contact angle of the magnetic particles modified with DA / PEI in Example 1;

[0031] Figure 6 is the water contact angle of the sponge modified with DA / PEI in Example 1;

[0032] Figure 7 3. This is a diagram showing the oil-water separation effect of the sponge material with a wettability gradient on the surfactant-stabilized emulsion at different hydraulic retention times in Example 2;

[0033] Figure 8 This is a diagram showing the oil-water separation effect of the sponge material with a wettability gradient and the sponge material with a single wettability on an emulsion without a surfactant in Comparative Example 1;

[0034] Figure 9 This is a diagram showing the oil-water separation effect of the sponge material with a wettability gradient and the sponge material with a single wettability on the surfactant-stabilized emulsion in Comparative Example 2. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0036] like Figure 1 As shown, a method for constructing a composite wetting structure sponge for continuous treatment of oil-in-water emulsions comprises the following steps:

[0037] S1: Preparation of sponge substrate: A sponge was selected as the substrate, cut into cylinders, ultrasonically cleaned in ethanol, rinsed three times with deionized water, and then ultrasonically cleaned in deionized water; the sponge was squeezed to remove excess water, and then dried in a vacuum drying oven at 60°C for 2 h to obtain the sponge substrate;

[0038] S2: Using a one-pot method, polyethyleneimine, dopamine, Tris-HCl buffer, magnetic particles, and sponge are placed in a three-necked flask to react to obtain the modified sponge material;

[0039] S3: Remove the sponge from the modification solution and rinse it with deionized water for more than five times until the rinse solution is clear and transparent. Squeeze out excess water and dry it in a vacuum drying oven to a constant weight. After drying, remove the sponge to obtain the finished sponge material MP@MS with a wettability gradient.

[0040] S4: The sponge material MP@MS is fixed in the filter column of the continuous oil-water separation device. Under the action of the peristaltic pump, the emulsion containing the surfactant flows from bottom to top in the filter column. The MP@MS absorbs oil and filters water to achieve oil-water separation.

[0041] Furthermore, the sponge in step S1 of the present invention may be a melamine sponge, a polyurethane sponge or a polydimethylsiloxane sponge.

[0042] Furthermore, the one-pot reaction solution in step S2 of the present invention is a Tris-HCl buffer solution with a Tris concentration of 0.01M and a pH of 8.5. The reaction temperature is 30-50°C. The preparation process requires a stirring speed of 200-300 rpm for 6-12 hours. Oxygen must be introduced throughout the reaction process. The key materials and their amounts are: 2-4 g / L polyethyleneimine, 2-4 g / L dopamine, 2-4 g / L 0.1-10 μm commercial magnetic particles, and a volume of 5-20 cm 3 sponge.

[0043] Furthermore, in step S3 of the present invention, the finished sponge material having a wettability gradient is modified so that the magnetic particles have a large number of hydroxyl and amino groups, and the sponge exposes more benzene ring structures; the water contact angle of the magnetic particles is 0 to 15°, and the water contact angle of the modified sponge is 120 to 140°.

[0044] Furthermore, in step S3 of the present invention, the MP@MS sponge structure with a wettability gradient is a structure in which hydrophilic magnetic particles are distributed in the nodes of the sponge skeleton in a honeycomb flocculent state, making the surface of the sponge skeleton rough and uneven.

[0045] like Figure 2 As shown, the continuous oil-water separation device in step S4 of the present invention includes a peristaltic pump, a filter column, and an outlet water transmittance monitoring system. The head end of the device is the emulsion to be treated. The peristaltic pump drives the directional flow of the emulsion. The flow direction in the filter column is bottom-in and top-out to avoid short-circuiting. The filtrate treated by the filter column flows through the outlet water transmittance monitoring link, and the treated filtrate is collected at the tail end of the device. The sponge compression ratio of the sponge material MP@MS in the filter column is 25% to 75%; the flow rate of the emulsion containing surfactant entering the filter column is 5 to 100 mL / h; and the hydraulic retention time of the emulsion is 4 to 15 minutes. The outlet water transmittance monitoring link can be an ultraviolet spectrophotometer, which monitors the transmittance of the filtrate at a wavelength of 610 nm in real time to analyze the oil-water separation effect of the sponge.

[0046] Furthermore, in step S4 of the present invention, the emulsion can be prepared by anionic surfactants, cationic surfactants, and nonionic surfactants, and the surfactant concentration is 50ppm to 500ppm; and the emulsion oil phase includes dichloromethane, chloroform, carbon tetrachloride, petroleum ether, hexadecane, soybean oil, liquid paraffin, vacuum pump oil and engine oil, etc., the concentration of the oil phase is 1000ppm to 10000ppm, and the oil droplet particle size is 5μm to 15μm.

[0047] The present invention uses a one-pot process to prepare a sponge material with a wettability gradient, MP@MS. Hydrophilic particles are uniformly and efficiently loaded onto a hydrophobic sponge skeleton. The material then processes surfactant-stabilized oil-in-water emulsions with the aid of an oil-water separator. After continuous, extended treatment, the filtrate maintains a water transmittance of 80%, demonstrating the material's long-lasting adsorption and demulsification capabilities. The present method for preparing a sponge material with a wettability gradient is simple and convenient; its long-lasting processing capacity allows for continuous oil-water separation of surfactant-stabilized emulsions, potentially enabling large-scale emulsion processing. This provides a valuable insight into the design and development of three-dimensional demulsification materials.

[0048] The following is detailed description in conjunction with specific embodiments:

[0049] Example 1

[0050] A method for constructing a composite wetting structure sponge for continuous treatment of oil-in-water emulsions, comprising the following steps:

[0051] S1: Preparation of sponge substrate: Melamine sponge was selected as the substrate and cut into cylinders with a diameter of 2 cm and a height of 3 cm. The cylinders were ultrasonically cleaned in ethanol for 30 min, rinsed three times with deionized water, and then ultrasonically cleaned in deionized water for 10 min. The sponge was squeezed to remove excess water and then dried in a vacuum drying oven at 60°C for 2 h to obtain the sponge substrate.

[0052] S2: Using a one-pot method, 3 g / L polyethyleneimine, 3 g / L dopamine, 200 mL of 0.01 M Tris-HCl buffer (pH 8.5), 2 g / L of 1 μm commercial magnetic particles, and three sponges were placed in a 250 mL three-necked flask. The mixture was heated in a 40°C water bath and stirred at 300 rpm for 8 h to obtain the modified sponge material.

[0053] S3: Remove the sponge from the modification solution and rinse it with deionized water for more than five times until the rinse solution is clear and transparent. Squeeze out excess water and dry it in a vacuum drying oven for 12 hours. After drying, remove the finished sponge material MP@MS with a wettability gradient.

[0054] S4: The sponge material MP@MS is fixed in the filter column of the continuous oil-water separation device. Under the action of the peristaltic pump, the emulsion containing the surfactant flows from bottom to top in the filter column. The sponge material MP@MS absorbs oil and filters water to achieve oil-water separation.

[0055] The surface of the sponge material was observed and characterized by SEM. Figure 3 As shown in the SEM characterization results, the melamine sponge has a slender skeleton and an intricate pore structure. The unmodified sponge skeleton has a smooth surface ( Figure 3 (a)). The sponge with a wetting gradient has a large number of honeycomb flocs, which are mainly distributed on the nodes of the sponge skeleton, making the skeleton surface rough and uneven. These are hydrophilic magnetic particles modified by DA / PEI and bonded to the sponge. They are also the demulsification sites during the subsequent treatment of the emulsion. Through this random combination and the combination with the lipophilic surface of the substrate, the uneven distribution of the hydrophilic and hydrophobic surfaces of the sponge is achieved ( Figure 3 (b)).

[0056] FTIR was used to analyze the chemical bonds or functional groups of the magnetic particles modified with DA / PEI. Figure 4 As shown. According to the FTIR characterization results, at 3430cm -1 A prominent and broad absorption peak is formed at the position of 1100 cm, indicating that a large number of hydroxyl and amino groups are introduced into the MP after DA / PEI modification; -1 and 2920cm -1 The absorption peak at 1567cm is caused by the asymmetric vibration of CH, mainly from PEI; -1 The absorption peak comes from the self-polymerization of DA and the stretching vibration of C=N in the PEI molecule.

[0057] The wettability of the DA / PEI modified magnetic particles was characterized by water contact angle. Figure 5 The contact angle characterization results show that the water contact angle of the original MP is 13.7°. When the MP is modified with 2g / L dopamine and 2g / L polyethyleneimine, it shows stronger hydrophilicity, with WCA of 0°. The water droplet will completely spread and wet the filter cake surface the moment it touches the filter cake surface.

[0058] The wettability of the DA / PEI modified sponge was characterized by water contact angle. Figure 6 The contact angle characterization results show that the water contact angle of the original sponge is 0°. After modification with 2 g / L dopamine and 2 g / L polyethyleneimine, the water contact angle of the sponge is 137.8°.

[0059] Example 2

[0060] The sponge material with a wetting gradient prepared in Example 1 was used to treat the emulsion stabilized by a nonionic surfactant at different hydraulic retention times. Figure 7 As shown. The emulsion is prepared by configuring 50ppm of non-ionic surfactant Tween80, the emulsion oil is liquid paraffin, the oil phase concentration is 10000ppm, and the oil droplet size is 6.4μm. It can be seen from the treatment effect that when the HRT is 4.6min, the water transmittance begins to decay rapidly at the initial stage of treatment. An HRT that is too short is not enough for the sponge to exert the effect of demulsification and oil absorption. When the HRT is 9.2min, the water transmittance reaches a plateau, and the material begins to realize a continuous demulsification and oil absorption process, which initially reflects the advantages of long-term treatment. When the HRT reaches 13.8min, the long-term water purification effect is significant, and when the processing volume reaches 100mL, the water transmittance is still 80%. This embodiment shows that in order for the material to exert a better demulsification and oil absorption effect, the HRT needs to be higher than a certain critical value.

[0061] Comparative Example 1

[0062] The sponge material MP@MS with a wettability gradient and the sponge material MS with a single wettability gradient prepared in Example 1 were used to treat the emulsion without surfactant. The treatment effect was as shown in the attached figure. Figure 8 As shown. No magnetic particles were added to the sponge material with a single wetting gradient in the one-pot method, and the rest was consistent with the process for preparing the sponge material MP@MS. The emulsion was prepared by configuring 10,000 ppm of liquid paraffin. From the treatment effect, it can be seen that the effluent transmittance of MS was first maintained at a high value close to 95%, and reached the treatment limit after treating 20 mL, and then the effluent water quality dropped sharply. In contrast, the effluent transmittance of the sponge material MP@MS was close to 100% at the initial stage of treatment, and maintained a good water purification effect for a very long treatment time. The treatment effect declined slowly with the increase in treatment volume, and the effluent transmittance was still maintained above 80% after treating 180 mL. This comparative example proves that the sponge material MP@MS has long-term treatment advantages for emulsions that do not contain surfactants.

[0063] Comparative Example 2

[0064] The sponge material MP@MS with a wetting gradient prepared in Example 1 and the sponge material MS with a single wetting gradient were used to treat the surfactant-stabilized emulsion. The treatment effects are shown in the attached figure. Figure 9As shown. No magnetic particles were added to the sponge material with a single wetting gradient in the one-pot method, and the rest was consistent with the process for preparing the sponge material MP@MS. The emulsion was prepared by configuring 50ppm of the non-ionic surfactant Tween80, the oil phase of the emulsion was liquid paraffin, the oil phase concentration was 10000ppm, and the oil droplet size was 6.4μm. From the treatment effect, it can be seen that after treating 100mL of emulsion, the water transmittance of MS has dropped to below 10%, while the sponge material MP@MS can still ensure that the water transmittance reaches about 80%. This comparative example proves that the sponge material MP@MS has long-term treatment advantages for surfactant-stabilized emulsions.

[0065] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A method for constructing a composite wetting structure sponge for continuous treatment of oil-in-water emulsions, characterized in that: Here are the steps: S1: Preparation of sponge substrate: A sponge was selected as the substrate, cut into cylinders, ultrasonically cleaned in ethanol, rinsed three times with deionized water, and then ultrasonically cleaned in deionized water again; the sponge was squeezed to remove excess water, and then dried in a vacuum drying oven at 60°C for 2 h to obtain the sponge substrate; S2: Using a one-pot method, polyethyleneimine, dopamine, Tris-HCl buffer, magnetic particles, and sponge are placed in a three-necked flask to react to obtain the modified sponge material; S3: Remove the sponge from the modification solution and rinse it with deionized water for more than five times until the rinse solution is clear and transparent. Squeeze out excess water and dry it in a vacuum drying oven to a constant weight. After drying, remove the sponge to obtain the finished sponge material MP@MS with a wettability gradient. S4: The sponge material MP@MS is fixed in the filter column of the continuous oil-water separation device. Under the action of the peristaltic pump, the emulsion containing the surfactant flows from bottom to top in the filter column. The sponge material MP@MS absorbs oil and filters water, achieving oil-water separation; In step S3, the finished sponge material with a wettability gradient is modified so that the magnetic particles have a large number of hydroxyl and amino groups, and the sponge exposes more benzene ring structures; the water contact angle of the magnetic particles is 0-15°, and the water contact angle of the modified sponge is 120-140°.

2. The method for constructing a composite wettable structure sponge for continuous treatment of oil-in-water emulsion according to claim 1, characterized in that: The sponge in step S1 is melamine sponge, polyurethane sponge or polydimethylsiloxane sponge.

3. The method for constructing a composite wettable structure sponge for continuous treatment of oil-in-water emulsion according to claim 1, characterized in that: The one-pot reaction solution in step S2 is a Tris-HCl buffer solution with a Tris concentration of 0.01 M and a pH of 8.

5. The reaction temperature is 30-50°C. The preparation process needs to be stirred at a speed of 200-300 rpm for 6-12 hours, and oxygen needs to be introduced throughout the reaction process.

4. The method for constructing a composite wettable structure sponge for continuous treatment of oil-in-water emulsion according to claim 1, characterized in that: The key materials and dosages in step S2 are: 2-4 g / L polyethyleneimine, 2-4 g / L dopamine, 2-4 g / L 0.1-10 μm commercial magnetic particles, and a volume of 5-20 cm 3 sponge.

5. The method for constructing a composite wettable structure sponge for continuous treatment of oil-in-water emulsion according to claim 1, characterized in that: In step S3, the sponge structure of the finished sponge material MP@MS with a wettability gradient is that the hydrophilic magnetic particles are distributed in the nodes of the sponge skeleton in a honeycomb flocculent state, making the surface of the sponge skeleton rough and uneven.

6. The method for constructing a composite wettable structure sponge for continuous treatment of oil-in-water emulsion according to claim 1, characterized in that: In step S4, the continuous oil-water separation device includes three parts: a peristaltic pump, a filter column, and an outlet water transmittance monitoring system.

7. The method for constructing a composite wettable structure sponge for continuous treatment of oil-in-water emulsion according to claim 5, characterized in that: The head end of the continuous oil-water separation device is the emulsion to be treated. The peristaltic pump drives the directional flow of the emulsion. The flow direction in the filter column is bottom-in and top-out to avoid short-circuiting. The filtrate treated by the filter column flows through the water transmittance monitoring link, and the treated filtrate is collected at the tail end of the continuous oil-water separation device.

8. The method for constructing a composite wettable structure sponge for continuous treatment of oil-in-water emulsion according to claim 5, characterized in that: The sponge compression ratio of the finished sponge material MP@MS in the filter column is 25%~75%; the flow rate of the surfactant-containing emulsion entering the filter column is 5~100 mL / h; and the hydraulic retention time of the emulsion is 4 min~15 min.

9. The method for constructing a composite wettable structure sponge for continuous treatment of oil-in-water emulsion according to claim 5, characterized in that: The water transmittance monitoring link is an ultraviolet spectrophotometer, which monitors the transmittance of the filtrate at a wavelength of 610 nm in real time to analyze the oil-water separation effect of the sponge.

10. The method for constructing a composite wettable structure sponge for continuous treatment of oil-in-water emulsion according to claim 1, characterized in that: In step S4, the emulsion is prepared by mixing anionic surfactant, cationic surfactant and nonionic surfactant, and the surfactant concentration is 50 ppm to 500 ppm; the concentration of the oil phase is 1000 ppm to 10000 ppm, and the oil droplet size is 5 μm to 15 μm.

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