High-flux oil-water separation device, oil-water separation method and application

Abstract

The invention relates to the field of oil-water separation equipment, in particular to a high-flux oil-water separation device, an oil-water separation method and application. The oil-water separation device comprises a liquid inlet cavity, a liquid inlet is formed in the liquid inlet cavity, an ultra-spreading polypropylene fiber membrane is arranged at one end of the liquid inlet cavity, and an oleophylic fiber membrane is arranged at the other end of the liquid inlet cavity; the oil-water separation device further comprises a water outlet and an oil outlet, the water outlet is communicated with the liquid inlet cavity through the ultra-spreading polypropylene fiber membrane, and the oil outlet is communicated with the liquid inlet cavity through the oleophylic fiber membrane; the static contact angle between the ultra-spreading polypropylene fiber membrane and water can reach 0 degree within 1 second or less. According to the oil-water separation device, efficient separation of oil and water is achieved, and the application range of efficient oil-water separation achieved through a membrane material is widened. The oil-water separation device disclosed by the invention is simple, high in water-oil flux and extremely high in application value.

Description

Technical Field

[0001] The present invention relates to the field of oil-water separation equipment, and in particular to a high-throughput oil-water separation device, an oil-water separation method and applications. Background Art

[0002] With the rapid development of industry, environmental pollution is getting worse. Water pollution is the most common environmental problem. my country's water resources, especially fresh water resources, are not abundant, and water pollution has brought great harm to water resources. The most common water pollution is oily wastewater pollution. In many fields such as crude oil mining, textiles, and metallurgy, there is the discharge of oily wastewater, which has caused serious pollution to water resources. Therefore, how to treat oily wastewater is of great value.

[0003] According to different principles, it can be divided into physical method, physical and chemical method, chemical method and biological method. Among them, the physical method can be divided into gravity method, centrifugal method and membrane separation method. Membrane separation method has the characteristics of low energy consumption and easy operation, and has achieved rapid development in recent years. Membrane separation method can be divided into negative pressure drive method and gravity drive method. Negative pressure drive requires a pressure difference to be applied on both sides of the membrane to achieve separation. Gravity drive refers to the separation of water under the action of gravity. Among them, membrane material is an important factor affecting the separation effect and efficiency.

[0004] The current membrane materials can be divided into hydrophobic / oleophilic membranes and hydrophilic / oleophobic membranes, but the flux in the existing technology is insufficient and cannot achieve efficient oil-water separation. In addition, the cost of membrane materials in the existing technology is high and cannot meet the rapidly growing demand for sewage treatment. Summary of the invention

[0005] In view of the technical problems existing in the prior art, the present invention provides a highly efficient oil-water separation device and method. The device uses a super-spreading polypropylene fiber membrane material with water super-spreading performance as a water separation membrane, and has excellent water treatment flux, can achieve the treatment of a large amount of oily wastewater, and has the characteristics of high efficiency and easy operation.

[0006] The first aspect of the present invention is to provide an oil-water separation device, comprising a liquid inlet cavity, the liquid inlet cavity is provided with a liquid inlet, one end of the liquid inlet cavity is provided with a super-spreading polypropylene fiber membrane, and the other end is provided with an oleophilic fiber membrane;

[0007] The oil-water separation device further comprises a water outlet and an oil outlet, wherein the water outlet is connected to the liquid inlet cavity through the super-spread polypropylene fiber membrane, and the oil outlet is connected to the liquid inlet cavity through the oleophilic fiber membrane;

[0008] The super-spread polypropylene fiber membrane contains a polypropylene fiber membrane matrix and an amphiphilic polymer. Taking the mass of the super-spread polypropylene fiber membrane as 100%, the content of the polypropylene fiber membrane matrix in the super-spread polypropylene fiber membrane is 93%-99.99%; the content of the amphiphilic polymer is 0.01%-7%; the static contact angle of the super-spread polypropylene fiber membrane with water can reach 0° within no more than 1 second.

[0009] In the present invention, the super-spread polypropylene fiber membrane is a super-hydrophilic polypropylene fiber membrane without a layered structure.

[0010] The so-called superspreading (superspreading, superdiffusion or superwetting) is a common term in this field. For example, the paper "Superspreading Phenomenon and Nature of Silicon Surfactants" in "Daily Chemicals Science" Issue 8, 2019, and the paper "Research Progress of Superspreading Characteristics of Fluids on Solid Surfaces" in "Chemical Industry Journal" Volume 65 Issue 3 (March 2014) all involve descriptions of superspreading. Generally, it means that a small volume of droplets (less than 2μl, excluding the influence of gravity) can quickly achieve a contact angle of 0° after contacting the surface of an object. For example, the superspreading polypropylene fiber membrane of the present invention reaches a static contact angle of 0 degrees for water in no more than 1 second, preferably in 0.005 seconds-1 second. Compared with traditional superhydrophilic materials (contact angle less than 5°), materials with superspreading properties have better hydrophilicity, can make liquids quickly transfer and flow in the material, and have high throughput, so they have significant advantages in separation, filtration and other fields. The superspreading polypropylene fiber membrane of the present invention refers to a water superspreading polypropylene fiber membrane.

[0011] According to the present invention, the super-spread polypropylene fiber membrane comprises a polypropylene fiber membrane matrix and an amphiphilic polymer, and based on the mass of the super-spread polypropylene fiber membrane as 100%, the content of the polypropylene fiber membrane matrix in the super-spread polypropylene fiber membrane is 93%-99.99%; the content of the amphiphilic polymer is 0.01%-7%; the static contact angle of the polypropylene fiber membrane with water can reach 0° within a time not exceeding 1 second. In a preferred embodiment of the present invention, based on the mass of the super-spread polypropylene fiber membrane as 100%, the content of the polypropylene fiber membrane matrix in the super-spread polypropylene fiber membrane is 95%-99.95%, for example, it can be 95%, 97%, 98.3%, 99%, 99.95%, and any two values ​​or any interval between any two values; the content of the amphiphilic polymer is 0.05%-5%, for example, 0.01%, 0.7%, 3%, 5%, and any two values ​​or any interval between any two values.

[0012] Preferably, the sum of the content of the polypropylene fiber membrane matrix and the content of the amphiphilic polymer is 100%.

[0013] According to the present invention, the mass content of the amphiphilic polymer in the super-spread polypropylene fiber membrane can be detected by conventional detection methods in the art, including but not limited to the following methods: take an unmodified polypropylene non-woven fabric and weigh its mass m1, treat it by the method listed in the embodiment and then dry it to obtain a treated polypropylene fiber membrane, weigh its mass m2, and the percentage (m2-m1) / m2×100% is the mass content of the amphiphilic polymer.

[0014] According to the present invention, the content of the amphiphilic polymer per unit surface area of ​​the super-spread polypropylene fiber membrane can be selected in a wide range. In a preferred embodiment of the present invention, the content of the amphiphilic polymer per unit surface area of ​​the super-spread polypropylene fiber membrane is 0.005 g / m 2 -3g / m 2 , preferably 0.005g / m 2 -2g / m 2 , for example 0.005g / m 2 , 1g / m 2 , 2g / m 2 , and any two values ​​or any interval between any two values.

[0015] According to the present invention, the content of the amphiphilic polymer per unit surface area of ​​the super-spread polypropylene fiber membrane can be detected by conventional detection methods in the art. Including but not limited to the following methods: first, the sample to be tested is coated with gold on the surface, and then the coated sample is placed on the SEM detection table, and the 5μm×5μm area on the sample is scanned by SEM, and then the mass fraction of oxygen in the polypropylene fiber membrane before modification and the polypropylene fiber membrane after hydrophilic modification is determined by EDS spectrum in this area, which are respectively recorded as w0 and w1, and calculated according to the following formula: W=(w1-w0) / (M O / M A )×M, where M O is the relative atomic mass of oxygen, M A is the molecular weight of a single chain segment of the amphiphilic polymer, M is the surface density of the polypropylene fiber membrane, and W is the content of the amphiphilic polymer per unit area of ​​the super-spread polypropylene fiber membrane.

[0016] According to the present invention, the polypropylene fiber membrane substrate has a wide range of options, and the fiber membrane substrate can be, for example, meltblown polypropylene nonwoven fabric, spunbonded polypropylene nonwoven fabric, or a multilayer composite fabric of meltblown polypropylene nonwoven fabric and spunbonded polypropylene nonwoven fabric.

[0017] According to the present invention, when the fiber diameter of the fiber membrane is within a certain range, capillary force can be generated between the fibers, thereby improving the hydrophilicity of the polypropylene fiber through the self-assembled amphiphilic polymer, so that water can spread at a very fast speed under the action of capillary force. In a preferred embodiment of the present invention, the fiber diameter in the super-spreading polypropylene fiber membrane is less than 20 microns, preferably less than 10 microns, and more preferably 0.1-10 microns.

[0018] The fiber diameter range of the polypropylene fiber membrane substrate in the present invention refers to the nominal fiber diameter range of commercially available polypropylene fiber membrane substrates in the art or the statistical value obtained by detection. As long as the nominal fiber diameter range or the statistical value obtained by detection is within the scope of the present invention, the situation that the diameter range of some (or several) fibers on the overall polypropylene fiber membrane substrate is not within the scope of the present invention also belongs to the protection scope of the present invention.

[0019] The above fiber diameter detection method can adopt conventional detection in the art, including but not limited to observing the fiber with a microscope, such as an electron microscope, an optical microscope, and measuring and statistically analyzing the fiber diameter.

[0020] According to the present invention, only amphiphilic and water-soluble polymers can achieve capillary self-assembly. In a preferred embodiment of the present invention, the amphiphilic polymer is selected from polyvinyl alcohol. The present invention achieves the coating of the amphiphilic polymer on the surface of the polypropylene fiber through capillary self-assembly, thereby achieving super-hydrophilic and super-spreading effects. Experimental verification shows that non-amphiphilic polymers cannot improve the polypropylene fiber membrane.

[0021] According to the present invention, the water-soluble amphiphilic copolymer refers to a polymer containing both a hydrophilic segment and a lipophilic segment in the molecular chain, and such a polymer has a certain affinity for two phases (usually a water phase and an oil phase) with different properties. Preferably, the amphiphilic polymer is polyvinyl alcohol and / or a cross-linked polymer formed by polyvinyl alcohol and a cross-linking agent; more preferably, it is a cross-linked polymer formed by polyvinyl alcohol and a cross-linking agent.

[0022] According to the present invention, in order to ensure the long-term and efficient operation of the separation device, the amphiphilic polymer undergoes a cross-linking reaction, and the selectable range of the cross-linking agent is relatively wide. In a preferred embodiment of the present invention, the cross-linking agent is selected from at least one of a polyacid and a polyaldehyde, including but not limited to at least one of glutaraldehyde and boric acid.

[0023] According to the present invention, the cross-linking agent is preferably selected from at least one of a polyacid and a polyaldehyde, more preferably glutaraldehyde and / or boric acid.

[0024] According to the present invention, the super-spread polypropylene fiber membrane is a super-hydrophilic polypropylene fiber membrane without a layered structure.

[0025] The layered structure refers to the layering of the modified fiber membrane (or fiber cloth). Taking the fiber membrane modified with an amphiphilic polymer as an example, the fiber membrane modified with an amphiphilic polymer having a layered structure is a layer of amphiphilic polymer formed on the surface of the fiber membrane matrix, that is, the amphiphilic polymer layer, and the fiber membrane matrix is ​​lined on one side of the amphiphilic polymer layer. The prior art mainly has a modified fiber membrane with a layered structure, which will form a functional material layer (such as a polymer layer or an inorganic layer) on one side or both sides of the membrane matrix. This type of functional material layer is a layered structure that is relatively independent of the membrane matrix on a macroscopic level. The weight and thickness of a small amount of functional material that penetrates into the membrane matrix are negligible compared to the functional material in the functional material layer, which is different from the polymer without a layered structure in the present invention.

[0026] The super-spread polypropylene fiber membrane of the present invention is a super-hydrophilic polypropylene fiber membrane without a layered structure. The amphiphilic polymer in the present invention does not have the above-mentioned layering. Instead, the amphiphilic polymer is wrapped around the outside of each fiber of the polypropylene fiber membrane.

[0027] According to the present invention, preferably, the amphiphilic polymer can self-assemble on the fiber surface in the polypropylene fiber membrane matrix, the lipophilic segments in the amphiphilic polymer are assembled on the polypropylene fiber surface, and the hydrophilic segments are distributed on the fiber surface after assembly, thereby improving the hydrophilicity of the polypropylene fiber membrane. Preferably, the super-spread polypropylene fiber membrane contains polypropylene fibers coated with amphiphilic polymers, which are observed under a transmission electron microscope after staining with metal ruthenium.

[0028] In a preferred embodiment of the present invention, the super-spread polypropylene fiber membrane contains polypropylene fibers coated with amphiphilic polymers. Preferably, the amphiphilic polymers are coated on the polypropylene fibers by capillary self-assembly. That is, self-assembly is achieved under the action of capillary force, the lipophilic segments in the water-soluble amphiphilic polymers are attached to the surface of the polypropylene fibers, and the hydrophilic segments are exposed to the outside, thereby forming a fiber surface with a hydrophilic structure. In application, the capillary structure of the fiber membrane itself is well retained, and coupled with the effect of the amphiphilic polymers, a hydrophilic / super-spreading effect is achieved under the action of capillary force. The amphiphilic polymers on the super-spread polypropylene fiber membrane of the present invention are different from the amphiphilic polymers cast or coated on the fiber membrane surface. The hydrophilicity distribution of the amphiphilic polymers of the present invention is more uniform, and the super-spread polypropylene fiber membrane of the present invention does not have an obvious layered structure.

[0029] In a preferred embodiment of the present invention, the method for preparing the super spread polypropylene fiber membrane comprises:

[0030] The method comprises contacting a polypropylene fiber membrane substrate with a solution containing an amphiphilic polymer under the action of an external force, wherein the content of the amphiphilic polymer in the solution is not higher than 5wt%, and optionally subjecting the polypropylene fiber membrane obtained after the polypropylene fiber membrane substrate is contacted with the amphiphilic polymer to a cross-linking reaction in a solution containing a cross-linking agent to obtain the super-spread polypropylene fiber membrane.

[0031] As described above, the water-soluble amphiphilic polymer realizes self-assembly under the action of capillary force, the lipophilic segments in the water-soluble amphiphilic polymer are attached to the surface of the polypropylene fiber, and the hydrophilic segments are exposed to the outside, thereby forming a fiber surface with a hydrophilic structure (i.e., the amphiphilic polymer is wrapped on the fiber surface), and the hydrophilic / super-spreading effect is achieved under the action of capillary force. The amphiphilic polymer in the present invention is more evenly distributed and has a non-layered structure.

[0032] Preferably, the contacting is performed in a solution containing an amphiphilic polymer.

[0033] The contact utilizes intermolecular forces to cause the amphiphilic polymer to self-assemble on the surface of the polypropylene fiber membrane fiber, thereby obtaining a polypropylene fiber membrane coated with the amphiphilic polymer. That is, the water-soluble amphiphilic polymer (hydrophilic, lipophilic, and soluble in water) used in the present invention can disperse the water-soluble polymer molecular chain and load it on the surface of the polypropylene fiber by a self-assembly method, thereby forming a fiber membrane with a super-hydrophilic effect. The super-spreading polypropylene fiber membrane realizes the hydrophilic modification of the polypropylene fiber membrane by the amphiphilic polymer by a capillary force self-assembly method.

[0034] The present invention has found through experiments that, after induction by external force, a water-soluble polymer having a hydrophilic segment and a lipophilic segment can be assembled with a polypropylene fiber membrane through a self-assembly method. Since polypropylene is a lipophilic polymer, the lipophilic segment in the water-soluble polymer is assembled on the fiber surface in the polypropylene fiber membrane. The interaction force between the hydrophilic segment and the polypropylene fiber is weak, and the hydrophilic segment cannot be assembled on the fiber surface, thereby being exposed to the outside. Therefore, the polypropylene fiber has hydrophilic properties, and the polypropylene fiber membrane also has hydrophilic and lipophilic properties, and the spreading time is fast. At the same time, the fiber diameter of the polypropylene fiber membrane in the present invention is preferably less than 20 microns, preferably less than 10 microns, and more preferably 0.1-10 microns. A strong capillary action can occur, and water can be quickly transferred along the fiber under the action of capillary force, so that the polypropylene fiber membrane has excellent spreading performance. The maximum size of a droplet with a volume of 2 μL is not less than 7 mm in the spreading area after the fiber membrane is spread, the maximum size of a droplet with a volume of 5 μL is not less than 8 mm in the spreading area after the fiber membrane is spread, the maximum size of a droplet with a volume of 8 μL is not less than 12 mm in the spreading area after the fiber membrane is spread, and the maximum size of a droplet with a volume of 12 μL is not less than 15 mm in the spreading area after the fiber membrane is spread.

[0035] In a preferred embodiment of the present invention, the content of the amphiphilic polymer in the solution containing the amphiphilic polymer is 0.05-4.5wt%, preferably 0.1-4.5wt%. Under the above-mentioned amphiphilic polymer concentration conditions and the action of external force, the contact utilizes intermolecular forces to cause the amphiphilic polymer to self-assemble on the surface of the polypropylene fiber membrane to obtain a polypropylene fiber membrane coated with the amphiphilic polymer.

[0036] As described above, the content of the amphiphilic polymer in the solution containing the amphiphilic polymer is 0.05-4.5wt%, preferably 0.1-4.5wt%, for example 0.1wt%, 0.5wt%, 1wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 4.5wt%, and any two values ​​or any range between any two values, more preferably 0.3-3wt%.

[0037] In a more preferred embodiment of the present invention, the contacting is carried out in a solution containing an amphiphilic polymer, so that the super-spreading performance of the obtained polypropylene fiber membrane is more uniform.

[0038] According to the present invention, the contact between the fiber membrane and the amphiphilic polymer can be carried out in a wide temperature range, preferably not exceeding the melting temperature of polypropylene and the amphiphilic polymer, and more preferably not exceeding the glass transition temperature of the amphiphilic polymer.

[0039] In a preferred embodiment of the present invention, the preparation method further includes a drying step after the polypropylene fiber membrane substrate is contacted with the amphiphilic polymer; preferably, the contact temperature and the drying temperature each do not exceed the melting temperature of the fiber membrane substrate and the amphiphilic polymer, and more preferably do not exceed the glass transition temperature of the amphiphilic polymer.

[0040] According to the present invention, preferably, the contact is carried out under the action of an external force; during the self-assembly process of the amphiphilic polymer on the surface of the polypropylene fiber, an external force can be used to induce its rapid assembly, and the external force is not limited to one or more of ultrasound, rolling, filtration, lamination, molding and the like.

[0041] According to the present invention, the range of conditions under which the external force acts is relatively wide, such as the treatment time, the number of treatments and the process conditions of the treatment method, and there is no specific limitation.

[0042] Preferably, the external force comprises a combination of one or more of ultrasound, rolling, filtration, lamination, and molding; more preferably,

[0043] The ultrasonic conditions include: the ultrasonic frequency is not less than 5kHz, preferably not less than 10kHz, such as 10kHz, 20kHz, 30kHz, 40kHz, 45kHz, 50kHz, 55kHz, 60kHz. The greater the ultrasonic power, the less the action time and the number of actions.

[0044] According to the present invention, the ultrasonic treatment equipment can be selected from conventional ultrasonic treatment equipment including but not limited to ultrasonic cleaning table, cell crusher, ultrasonic probe, industrial ultrasonic device, etc. The power of the specific ultrasonic treatment equipment is not particularly limited by the present invention. Preferably, the power is 50-750W, preferably 50-500W, and more preferably 150-350W.

[0045] According to the present invention, the selectable range of the time for ultrasonic treatment in the preparation step is relatively wide, and the ultrasonic time is related to the solution concentration, fiber diameter, and surface density. According to the process conditions of the embodiments of the present invention, preferably, the ultrasonic time is not less than 1 minute, preferably not less than 5 minutes, and more preferably 10-120 minutes, for example, it can be 10 minutes, 20 minutes, 30 minutes, 40 minutes, 60 minutes, 100 minutes, 120 minutes, and the like.

[0046] In another preferred specific embodiment of the present invention, the conditions for suction filtration can be selected in a wide range, and as the vacuum degree increases, the processing time and the number of processing times can be reduced. In a preferred embodiment of the present invention, the conditions for suction filtration include: the vacuum degree is not less than 5Pa, preferably not less than 10Pa, and / or the suction filtration time is not shorter than 1 second, preferably not less than 5 seconds. Preferably, the infiltration state of the polypropylene fiber membrane substrate by the amphiphilic polymer solution is still maintained before stopping the suction filtration.

[0047] In another preferred specific embodiment of the present invention, the conditions for rolling include: the pressure is not less than 5 Pa, preferably not less than 10 Pa; and the number of rolling times is not less than 1 time.

[0048] In a more preferred embodiment of the present invention, the preparation method may include the following steps:

[0049] The polypropylene fiber membrane substrate is placed in a solution containing an amphiphilic polymer and brought into contact with the solution containing an amphiphilic polymer under the action of an external force; the aqueous solution of the amphiphilic polymer is immersed in the polypropylene fiber membrane substrate; and the process is dried.

[0050] As described above, in a preferred embodiment of the present invention, the amphiphilic polymer is selected from polyvinyl alcohol. That is, self-assembly is achieved under the action of capillary force, the lipophilic segments in the water-soluble amphiphilic polymer are attached to the surface of the polypropylene fiber, and the hydrophilic segments are exposed to the outside, thereby forming a fiber surface with a hydrophilic structure. In application, the capillary structure of the fiber membrane itself is well retained, and coupled with the effect of the amphiphilic polymer, the hydrophilic / super-spreading effect is achieved under the action of capillary force.

[0051] The amphiphilic polymer on the super-spread polypropylene fiber membrane of the present invention is different from the amphiphilic polymer cast or coated on the fiber membrane surface. The hydrophilicity distribution of the amphiphilic polymer of the present invention is more uniform, and the super-spread polypropylene fiber membrane of the present invention does not have an obvious layered structure. In addition, the amphiphilic polymer of the present invention is wrapped on the surface of the fiber, rather than cast or coated on one side of the fiber membrane. In this way, the capillaries between the fibers of the fiber membrane of the present invention are well retained. In addition, the effect of the amphiphilic polymer enables water to achieve a hydrophilic / super-spreading effect under the action of capillary force in the application.

[0052] According to the present invention, there is no particular limitation on the molecular weight of the amphiphilic polymer, for example, the number average molecular weight may be 30000-300000. Taking the embodiments of the present invention as an example, polyvinyl alcohol with a degree of polymerization of 1700 may be selected.

[0053] According to the present invention, the polypropylene fiber film substrate has a wide range of options, for example, it can be meltblown polypropylene non-woven fabric, spunbond polypropylene non-woven fabric, meltblown and spunbond polypropylene composite non-woven fabric, spunlace polypropylene non-woven fabric, etc. According to the present invention, meltblown polypropylene non-woven fabric and meltblown and spunbond polypropylene composite non-woven fabric are preferred.

[0054] According to the present invention, preferably, the surface density of the polypropylene fiber membrane substrate is 10-60 g / m 2 , preferably 20-50g / m 2 , and / or, the fiber diameter is not greater than 20 microns, preferably less than 10 microns, more preferably 0.1-10 microns. In this preferred embodiment, the fiber diameter of the fiber membrane generates capillary force between the fibers, thereby improving the hydrophilicity of the polypropylene fiber through the self-assembled amphiphilic polymer, and after encountering water, the water can spread at a very fast speed under the action of capillary force.

[0055] The fiber diameter range of the polypropylene fiber membrane substrate in the present invention refers to the nominal fiber diameter range of the commercially available polypropylene fiber membrane substrate in the art or the statistical value obtained by detection. As long as the nominal fiber diameter range or the statistical value obtained by detection is within the scope of the present invention, the situation that the diameter range of some (or several) fibers on the overall polypropylene fiber membrane substrate is not within the scope of the present invention also belongs to the protection scope of the present invention. The above fiber diameter detection method can adopt conventional detection in the art, including but not limited to observing the fiber with a microscope, such as an electron microscope, an optical microscope, and measuring and statistically analyzing the fiber diameter.

[0056] The preparation method further comprises an optional cross-linking step, which can be performed optionally according to specific uses, and preferably comprises a cross-linking step.

[0057] When the cross-linking step is included, the polypropylene fiber membrane obtained by contacting the polypropylene fiber membrane substrate with the amphiphilic polymer is subjected to cross-linking reaction in a solution containing a cross-linking agent.

[0058] The cross-linked amphiphilic polymer forms a cross-linked structure, and the stability of the amphiphilic polymer in the fiber membrane is increased, thereby improving the hydrophilic stability.

[0059] The super-spreading performance stability refers to the degree of change in contact angle after the hydrophilic fiber membrane is completely immersed in deionized water and treated under ultrasonic cleaning conditions for 5 minutes, repeated 3 times. The smaller the change in contact angle, the better its hydrophilic stability.

[0060] According to the present invention, the cross-linking agent has a wide selection range. In a preferred embodiment of the present invention, the cross-linking agent is selected from at least one of a polyacid and a polyaldehyde, preferably at least one of glutaraldehyde and boric acid, more preferably glutaraldehyde; and / or,

[0061] The content of the crosslinking agent in the solution containing the crosslinking agent is 0.005-0.8 wt %, preferably 0.01-0.5 wt %; and / or, the temperature conditions for crosslinking include:

[0062] The cross-linking temperature does not exceed the glass transition temperature of the amphiphilic polymer, preferably 30-70°C; and / or the pH of the solution containing the cross-linking agent is 4-7; the cross-linking reaction time is 1 min-120 min, preferably 1 min-90 min, for example, it can be 1 min, 3 min, 5 min, 10 min, 20 min, 50 min, 70 min, 90 min, and any two values ​​or any interval between any two values.

[0063] The present invention has no particular limitation on the raw materials for adjusting pH, and any conventional acid or alkali raw materials in the art may be used.

[0064] According to the present invention, the fiber membrane that has been cross-linked can be cleaned to remove residual cross-linking agents and other substances. The present invention has no particular restrictions on the cleaning method, including but not limited to rinsing with water. In order to improve the efficiency of cleaning, it is preferably cleaned under ultrasonic conditions. The ultrasonic conditions here are not particularly limited by the present invention. For example, the frequency of ultrasound is 20-80kHz. Preferably, the ultrasonic cleaning time is 1-30 minutes / time, preferably 15-25 minutes / time, and the number of cleaning times is selected from 1-5 times, preferably 2-4 times.

[0065] According to the present invention, if the super-spread polypropylene fiber membrane needs to be dried, the drying temperature is not higher than the glass transition temperature of the amphiphilic polymer. When the treatment temperature is higher than the glass transition temperature, the amphiphilic polymer undergoes molecular segment movement, which will destroy the structure formed by its self-assembly and affect the super-spreading performance.

[0066] The present invention described above is a super-spread polypropylene fiber membrane and a preferred preparation scheme of the present invention.

[0067] According to the present invention, preferably, the super spread polypropylene fiber membrane has at least one of the following characteristics:

[0068] The super-spreading polypropylene fiber membrane has a static contact angle of 0 degrees with water within 0.005 seconds to 1 second; more preferably, the static contact angle of 0 degrees with water within 0.005 seconds to 1 second. For example, it can be 0.005 seconds, 0.01 seconds, 0.05 seconds, 0.1 seconds, 0.5 seconds, 0.9 seconds, 1 second, any two values ​​or any interval between any two values;

[0069] And / or, after a droplet with a volume of 2 μL is spread on the super-spread polypropylene fiber membrane, the maximum size of the spreading area is not less than 7 mm, after a droplet with a volume of 5 μL is spread on the super-spread polypropylene fiber membrane, the maximum size of the spreading area is not less than 8 mm, after a droplet with a volume of 8 μL is spread on the super-spread polypropylene fiber membrane, the maximum size of the spreading area is not less than 12 mm, and after a droplet with a volume of 12 μL is spread on the super-spread polypropylene fiber membrane, the maximum size of the spreading area is not less than 15 mm.

[0070] According to the present invention, preferably, the super spread polypropylene fiber membrane has a high specific surface area, preferably, the specific surface area of ​​the super spread polypropylene fiber membrane is greater than 0.3 m2 / g, preferably greater than 0.7 m2 / g.

[0071] The method for detecting the maximum size of the droplet spreading area on the fiber membrane can be detected by conventional detection methods in the art. Including but not limited to the following methods: stick the fiber membrane sample flat on a glass slide, and pay attention to keep the sample flat in the horizontal direction during the pasting process, then place the glass slide on the sample stage of the contact angle meter and fix it, and control the volume of the droplet by adjusting the instrument, and the volume can be 2μL, 5μL, 8μL, 12μL. Drop a drop of water on the center of the sample, remove the glass slide after the contact angle becomes 0 degrees, and measure the size of the spreading area. The shape of the spreading area is approximately circular, and its diameter or diagonal can be taken as the maximum size.

[0072] According to the present invention, the test of the time required for the static contact angle of the polypropylene fiber membrane to reach 0 degrees with water can be detected by conventional detection methods in the art. Including but not limited to the following methods: the fiber membrane sample is flat on a glass slide, and it is important to keep the sample flat in the horizontal direction during the pasting process, and then the glass slide is placed on the sample stage of the contact angle measuring instrument and fixed, and the instrument is adjusted to control the volume of water droplets below 2μL to the center of the sample, and the angle from the solid-liquid interface through the inside of the droplet to the vapor-liquid interface at the junction of the three phases is measured, which is the static contact angle (referred to as water contact angle). The time calculation starts from the droplet contacting the fiber membrane surface and adjusting the lift to leave the droplet, until the droplet is completely spread and the contact angle reaches 0 degrees. The volume is controlled to be below 2μL in order to eliminate the influence of gravity, and better illustrate that the polypropylene fiber membrane has good hydrophilicity and super spreading performance.

[0073] According to the present invention, the oleophilic fiber membrane can be a variety of oleophilic fiber membranes, and any oleophilic fiber membrane can be used as the oleophilic fiber membrane as long as it has oleophilic properties and a certain oil flux. It can be homemade or commercially available.

[0074] According to the present invention, preferably, the static contact angle between the oleophilic fiber membrane and the oil can be 0°, and / or the oil flux is not less than 1.0×10 5 L / m 2 h; The static contact angle between the oleophilic fiber membrane used in the embodiments of the present invention and the oil can reach 0°.

[0075] Preferably, the oleophilic fiber membrane is selected from at least one of a polypropylene fiber membrane and a modified polypropylene fiber membrane.

[0076] The super-spread polypropylene fiber membrane in the present invention has hydrophilic and lipophilic properties and can be used as a water separation membrane or an oil separation membrane. As long as the super-spread polypropylene fiber membrane is moistened with oil before use, it can be used as an lipophilic fiber membrane. The lipophilic fiber membrane is preferably selected from the super-spread polypropylene fiber membrane described in the present invention.

[0077] According to the present invention, the water flux of the oil-water separation device is not less than 6.0×10 4 L / m2 h, oil flux is not less than 1.0×10 5 L / m 2 ·h; preferably the water flux is not less than 6.5×10 4 L / m 2 ·h, oil flux is not less than 1.1×10 5 L / m 2 ·h; more preferably, the water flux is not less than 7.0×10 4 L / m 2 h, oil flux is not less than 1.2×10 5 L / m 2 h. The oil-water separation device of the present invention has a higher oil-water flux.

[0078] The water flux refers to the maximum amount of water that can be separated per square meter per hour through the oil-water separation device, and the oil flux refers to the maximum amount of oil that can be separated per square meter per hour through the oil-water separation device.

[0079] The calculation formula of water flux is shown in formula 1:

[0080] F 水通量 = / V 分离水 AΔt

[0081] where F 水通量 is the water flux, V 分离水 is the volume of separated water, A is the surface area of ​​the water separation membrane, and Δt is the separation time.

[0082] The calculation formula of oil flux is shown in Equation 2:

[0083] F 油通量 = / V 油离水 AΔt

[0084] where F 水通量 is the water flux, V 油离水 is the volume of separated water, A is the surface area of ​​the oil separation membrane, and Δt is the separation time.

[0085] like Figure 1 As shown, the oil-water separation device comprises a liquid inlet cavity, the liquid inlet cavity is provided with a liquid inlet port 1, one end of the liquid inlet cavity is provided with a super-spreading polypropylene fiber membrane 2, and the other end is provided with an oleophilic fiber membrane 3;

[0086] The oil-water separation device also includes a water outlet 4 and an oil outlet 5. The water outlet 4 is connected to the liquid inlet cavity through the super-spread polypropylene fiber membrane 2, and the oil outlet 5 is connected to the liquid inlet cavity through the oleophilic fiber membrane; the super-spread polypropylene fiber membrane is a super-hydrophilic polypropylene fiber membrane without a layered structure.

[0087] According to the present invention, preferably, a first supporting layer is provided on one or both sides of the super spread polypropylene fiber membrane; preferably, the water flux of the first supporting layer is not less than that of the super spread polypropylene fiber membrane, so that it can support the super spread polypropylene fiber membrane without reducing the water flux.

[0088] According to the present invention, preferably, a second supporting layer is provided on one or both sides of the oleophilic fiber membrane, and preferably, the oil flux of the second supporting layer is not less than that of the oleophilic fiber membrane, so that the oleophilic fiber membrane can be supported without reducing the oil flux.

[0089] In the present invention, the super-spread polypropylene fiber membrane and the oleophilic fiber membrane are respectively connected to the cavity wall of the liquid inlet cavity through a sealing component. The sealing component can be a material and technology that can play a sealing role in the prior art, such as a sealing gasket, a sealant, etc.

[0090] The second aspect of the present invention is to provide a method for oil-water separation using the oil-water separation device of the first aspect, comprising:

[0091] First, the super spread polypropylene fiber membrane 2 is moistened with water, and preferably the oleophilic fiber membrane 3 is moistened with oil.

[0092] The oil-water mixture is then transported from the liquid inlet 1 to the liquid inlet chamber, the water phase in the oil-water mixture passes through the super-spreading polypropylene fiber membrane 2 and flows out from the water outlet 4, and the oil phase in the oil-water mixture passes through the oleophilic fiber membrane 3 and flows out from the oil outlet 5.

[0093] The separation device is driven by pressure difference or gravity, preferably by gravity without energy consumption. The water inlet passage is the passage for oily wastewater (oil-water mixture) to enter; the post-separation passage includes a water passage and an oil passage.

[0094] According to the present invention, the oil-water separation process may be negative pressure driven and / or gravity driven, and in the following embodiments it is gravity driven.

[0095] According to the present invention, the driving pressure of the oil-water separation process is greater than 0.01 MPa (water level height 0.1 cm), that is, all water above a height of 0.1 cm can flow out.

[0096] According to the present invention, in the oil-water separation method, clean water is used to wet the super-spread polypropylene fiber membrane, and the amount of water used is more than 1 times the weight of the polypropylene fiber membrane itself to ensure that the super-spread polypropylene fiber membrane can be completely wetted with water; the oily wastewater enters the device through the water inlet passage; the oily wastewater contacts the super-spread polypropylene fiber membrane and the oleophilic fiber membrane wetted with water, and the water in the oily wastewater enters the water passage through the super-spread polypropylene fiber membrane; the oil in the oily wastewater enters the oil passage through the oleophilic fiber membrane.

[0097] The oily wastewater can be any mixture of oily liquid and water, the oil-water ratio can be any ratio, and the density of the oil can be any density, which can be lower than or higher than the density of water. According to the present invention, the oil in the oily wastewater is preferably a low-viscosity oil.

[0098] The third aspect of the present invention is to provide an application of the oil-water separation device described in the first aspect or the method described in the second aspect in the field of oil-water separation processing.

[0099] The oil-water separation device of the present invention realizes efficient separation of oil and water, broadens the application scope of using membrane materials to realize efficient oil-water separation. The oil-water separation device of the present invention is simple, has high water-oil flux, and has extremely high application value.

[0100] Compared with the prior art, the present invention has the following advantages:

[0101] The oil-water separation device in the present invention can achieve efficient separation of oil and water, and the water flux of the separation treatment is higher than that of most existing oil-water separation technologies. In the present invention, a polypropylene fiber membrane with water super-spreading performance is used, and the polypropylene fiber membrane has relatively fine fibers and a hydrophilic fiber surface. When the super-spreading polypropylene fiber membrane is wetted with water, due to the effect of the surface tension of the oil-water interface, the oil droplets will form a spherical shape in the heterogeneous phase, and there are gaps between the fibers inside the fiber membrane. When the gaps are filled with water, the oil is affected by the surface tension and cannot enter between the gaps, and only water is allowed to pass through, thereby achieving the effect of oil-water separation. At the same time, the fiber diameter inside the super-spreading polypropylene fiber membrane is small, and a capillary effect can be formed. When the fiber is wetted with water, water can be quickly transferred inside the fiber membrane through the action of capillary force, thereby forming a large flux, that is, after the super-spreading polypropylene fiber membrane is wetted with water, it can block the oil from passing through, and only water can pass through, and the water flux is large. Similarly, when the oleophilic fiber membrane is wetted by oil, only oil can pass through it. In this way, oil-water separation is achieved under the action of the super-spread polypropylene fiber membrane and the oleophilic fiber membrane.

[0102] At the same time, the super-spread polypropylene fiber membrane used in the present invention is an oil-water amphiphilic fiber membrane, which can also be used as an oleophilic fiber membrane and also has a high oil flux. The reason why the polypropylene fiber membrane of the present invention has the above performance is that the inventors unexpectedly found that when the fiber diameter of the polypropylene fiber membrane is less than a certain size, capillary phenomena appear on the surface and inside of the fiber membrane, and the solution contacts the surface of the polypropylene fiber through the action of capillary force or with the help of external force during contact or impregnation with the aqueous solution of the amphiphilic polymer. When the content of the amphiphilic polymer in the solution of the amphiphilic polymer is not higher than 5wt%, the amphiphilic polymer molecular chains in the aqueous solution are uniformly dispersed, and the oleophilic segments (segments without hydroxyl groups) thereof show good compatibility with the equally oleophilic polypropylene, and self-assemble and combine after contacting with the polypropylene fiber membrane matrix. In this process, the amphiphilic polymer arranges the hydrophilic segments and the oleophilic segments separately, that is, the oleophilic segments are coated on the surface of the polypropylene fiber, and the hydrophilic segments are exposed on the surface of the polypropylene fiber after self-assembly, so that the polypropylene fiber membrane has hydrophilic properties. By controlling the process conditions (such as external force, concentration of amphiphilic polymer, etc.), the thin layer self-assembly of amphiphilic polymer on the surface of polypropylene fiber can be achieved. Through the combined action of capillary force and self-assembly, the polypropylene fiber membrane contains polypropylene fibers coated with amphiphilic polymer, and the polypropylene fiber membrane has super spreading performance. This process can occur better under the action of external force. For example, under the action of ultrasound, the amphiphilic polymer solution can quickly enter between the fiber membrane fibers, promote the contact between the lipophilic chain segments and the surface of the polypropylene fiber, thereby accelerating the speed and efficiency of self-assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0103] Figure 1 It is a structural schematic diagram of the oil-water separation device.

[0104] 1-liquid inlet; 2-super-spread polypropylene fiber membrane; 3-oleophilic fiber membrane; 4-water outlet; 5-oil outlet. DETAILED DESCRIPTION

[0105] The present invention is described in detail below in conjunction with specific embodiments. It is necessary to point out that the following embodiments are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made to the present invention by those skilled in the art based on the contents of the present invention still fall within the scope of protection of the present invention.

[0106] The experimental data in the examples were measured using the following instruments and measurement methods:

[0107] The water contact angle and spreading time (spreading time is the time required for the water contact angle to reach 0°) obtained in the embodiment are measured using the German EASYDROP contact angle tester: the fiber membrane is cut into samples of 1 cm×1 cm in size, and then the sample is flatly attached to a glass slide. During the pasting process, care should be taken to keep the sample flat in the horizontal direction. The glass slide is then placed and fixed on the sample stage of the EASYDROP contact angle meter. The instrument is adjusted to control the volume to 2 μL and a water droplet is dropped into the center of the sample. After 10 seconds, the angle at the three-phase junction from the solid-liquid interface through the inside of the droplet to the vapor-liquid interface is measured, which is the static contact angle (referred to as the water contact angle).

[0108] Water spreading area test method: Cut the fiber membrane into samples of 3cm×3cm in size, and place the samples flat on a flat glass. Then use a Masterflex 78018-10 peristaltic pump to pump deionized water drops of different volumes to the fiber membrane surface. After the water is completely spread, measure the maximum size at both ends of the spreading area as the spreading size.

[0109] Liquid content of hydrophilic polypropylene fiber membrane: Take a dry hydrophilic polypropylene fiber membrane and weigh it. Then rinse the sample with deionized water until there is no foam, hang it under the conditions of 25℃ and 30% humidity, and weigh it again after no water drops for 1 minute. The difference between the two weighings divided by the mass after drying is the liquid content of the sample, expressed in times.

[0110] The mass content of the amphiphilic polymer in the polypropylene fiber membrane obtained in the example: take an unmodified polypropylene non-woven fabric and weigh its mass m1. Treat it by the method listed in the example and then dry it to obtain a treated polypropylene fiber membrane, and weigh its mass m2. (m2-m1) / m2×100% is the mass content of the amphiphilic polymer.

[0111] The content of the amphiphilic polymer per unit surface area of ​​the polypropylene fiber membrane is as follows: first, the sample to be tested is coated with gold on the surface, and then the coated sample is placed on the SEM detection table, and a 5 μm×5 μm area on the sample is scanned by SEM, and then the mass fraction of oxygen in the polypropylene non-woven fabric before modification and the polypropylene fiber membrane after hydrophilic modification is determined by EDS energy spectrum in the area, which are respectively denoted as w0 and w1, and calculated according to the following formula: W=(w1-w0) / (M O / M A )×M, where M O is the relative atomic mass of oxygen, M A is the molecular weight of a single chain segment of the amphiphilic polymer, M is the surface density of the polypropylene non-woven fabric, and W is the content of the amphiphilic polymer per unit area of ​​the polypropylene fiber membrane.

[0112] The test method for the specific surface area of ​​super-spread polypropylene fiber membrane is as follows: Use a mercury intrusion instrument to test, weigh a certain mass of sample, transfer it into a dilatometer, and then seal and weigh it; put the weighed dilatometer into a low-pressure chamber, and then perform a high-pressure test, and calculate the specific surface area result through software.

[0113] In the following examples, polyvinyl alcohol, PVA-1799, degree of polymerization of 1700, degree of alcoholysis of 99%, glutaraldehyde (analytical grade), and hydrochloric acid with a concentration of 36% were purchased from Sinopharm.

[0114] Preparation of super-spread polypropylene fiber membrane

[0115] Preparation Example 1

[0116] Take polypropylene meltblown nonwoven fabric (purchased from Yanshan Petrochemical, specification 25g / m 2 , fiber diameter 0.5-8 microns) was immersed in a 0.3wt% polyvinyl alcohol (PVA-1799 from Sinopharm, glass transition temperature 72°C) aqueous solution at 25°C, and ultrasonically treated at a frequency of 50kHz for 30 minutes under a 250W ultrasonic probe. The treated polypropylene melt-blown was placed in a 0.5wt% glutaraldehyde cross-linking solution (pH 6) and cross-linked in a 60°C oven for 1 hour. The cross-linked polypropylene melt-blown was cleaned three times in a 100W ultrasonic water bath at a frequency of 50kHz, each time for 20 minutes, and then dried (at 60°C for 1 hour) to obtain an ultra-spread polypropylene fiber membrane.

[0117] The obtained polypropylene fiber membrane was tested for water contact angle, specific surface area, spreading time, etc. The specific test data are shown in Table 1.

[0118] Preparation Example 2

[0119] Take a three-layer composite fiber membrane of polypropylene spunbond nonwoven fabric and polypropylene meltblown fabric (purchased from Yanshan Petrochemical, model SMS, specification 50g / m 2 , fiber diameter 0.5-45 μm). Except that the ultrasonic treatment time during immersion in the polyvinyl alcohol aqueous solution was changed to 50 minutes, the rest was the same as in Example 1 to obtain an ultra-spread polypropylene fiber membrane. The specific test data are shown in Table 1.

[0120] Preparation Example 3

[0121] Take the polypropylene melt-blown nonwoven fabric in Preparation Example 1 and soak it in a 0.1wt% polyvinyl alcohol (from Aladdin, PVA-1799) aqueous solution at 25°C, and ultrasonically treat it at a frequency of 50kHz for 30 minutes under a 250W ultrasonic probe. The treated polypropylene melt-blown is arranged in a 0.5wt% glutaraldehyde cross-linking solution (pH is 6) and cross-linked in an 80°C oven for 1h. The cross-linked polypropylene melt-blown is arranged in a 100W ultrasonic water bath and cleaned three times at a frequency of 50kHz, each time for 20 minutes, and then dried (at 85°C for 1h). The glass transition temperature of PVA-1799 is 72°C. Specific test data are shown in Table 1 to obtain a modified polypropylene fiber membrane.

[0122] Preparation Example 4

[0123] PVA 1750 (purchased from Shandong Jiaying Chemical Technology Co., Ltd.) was mixed with deionized water at 90°C to form a concentrated aqueous solution with a concentration of 0.8 wt%. 500 ml of PVA solution was weighed and mixed with 600 ml of cross-linking solution to obtain a mixed solution. The cross-linking solution contained 45 ml of glutaraldehyde aqueous solution (50 wt%), acetic acid aqueous solution (10 vol%), methanol aqueous solution (10 vol%), and sulfuric acid aqueous solution (10 vol%), and the volume ratio of the three was 3:2:1. Polypropylene melt-blown nonwoven fabric (Sinopec Yanshan Petrochemical, with a surface density of 25 g / m 2 ) was placed in the mixed solution and vibrated at 150 rpm in a shaking incubator at 50°C for 60 minutes, then placed in deionized water for 1 hour to remove the residual crosslinking agent and PVA, and finally dried in a 50°C oven for one hour to obtain a modified polypropylene fiber membrane. The specific test results are shown in Table 1.

[0124] Preparation Example 5

[0125] The concentration of the PVA aqueous solution was changed to 0.1 wt %, the cross-linking agent was changed to boric acid, the mass fraction of the cross-linking agent was 0.5 wt %, the cross-linking time was 90 minutes, and the remaining operations were the same as those in Preparation Example 1. The specific test data are shown in Table 1.

[0126] Example 1

[0127] The super-spread polypropylene fiber membrane prepared in Preparation Example 1 was wetted with water as the water separation membrane in the separation component (i.e., the oil-water separation device), and polypropylene melt-blown non-woven fabric (purchased from Yanshan Petrochemical, specification 25g / m 2 , fiber diameter 0.5-8 microns) as oil separation membrane.

[0128] The water-wetted super-spread polypropylene fiber membrane and the oil-wetted polypropylene melt-blown non-woven fabric are fixed to the water outlet and the oil outlet in the separation component through the sealing silica gel. Take 1000ml of the oil-water mixture (a mixture of n-hexane and water, the total volume of the mixture is 100%, the water volume is 50%, and the mass of n-hexane is 50%), pour it into the water inlet channel, and the oil-water mixture enters the liquid inlet cavity of the separation component. After the mixture contacts the water-wetted super-spread polypropylene fiber membrane and the polypropylene melt-blown non-woven fabric, the water enters the water passage through the water-wetted super-spread polypropylene fiber membrane, and the oil enters the oil passage through the oil separation membrane. The water passage and the oil passage are connected to a beaker with a weighable volume, and the time is recorded to calculate the water flux and the oil flux. The results are shown in Table 2.

[0129] Example 2

[0130] The super-spread polypropylene fiber membrane prepared in Preparation Example 1 was wetted with water and used as the water separation membrane in the separation component, and the super-spread polypropylene fiber membrane in Preparation Example 1 wetted with oil was used as the oil separation membrane.

[0131] The water-wetted super-spread polypropylene fiber membrane and the oil-wetted super-spread polypropylene fiber membrane are fixed in the separation component. Take 1000ml of oil-water mixture (a mixture of n-hexane and water, with the total volume of the mixture as 100%, the water volume is 50%, and the n-hexane mass is 50%), pour it into the water inlet channel, and the oil-water mixture enters the separation component. After the mixture contacts the water-wetted super-spread polypropylene fiber membrane and the oil-wetted super-spread polypropylene fiber membrane, water enters the water passage through the water-wetted super-spread polypropylene fiber membrane, and oil enters the oil passage through the oil-wetted super-spread polypropylene fiber membrane. The water passage and the oil passage are connected to a beaker with a weighable volume, and the time is recorded to calculate the water flux and the oil flux. The results are shown in Table 2.

[0132] Example 3

[0133] The super spread polypropylene fiber membrane prepared in Preparation Example 2 was wetted with water as the water separation membrane in the separation component, and the super spread polypropylene fiber membrane in Preparation Example 2 wetted with oil was used as the oil separation membrane. The water-wetted super spread polypropylene fiber membrane and the oil-wetted super spread polypropylene fiber membrane were fixed in the separation component.

[0134] 1000ml of oil-water mixture (crude oil and water mixture, taken from Shengli Oilfield, with the total volume of the mixture as 100%, the volume of water as 95%, and the mass of n-hexane as 5%) was poured into the water inlet channel, and the oil-water mixture entered the separation component. After the mixture contacted the water-wetted super-spread polypropylene fiber membrane and the oil-wetted super-spread polypropylene fiber membrane, water entered the water passage through the water-wetted super-spread polypropylene fiber membrane, and oil entered the oil passage through the oil-wetted super-spread polypropylene fiber membrane. The water passage and the oil passage were connected to a beaker with a weighable volume, and the time was recorded to calculate the water flux and the oil flux. The results are shown in Table 2.

[0135] Example 4

[0136] The super-spread polypropylene fiber membrane of Preparation Example 5 was used to replace the super-spread fiber membrane in Example 1 as the water separation membrane, and the other conditions were the same as those in Example 1.

[0137] Comparative Example 1

[0138] Polypropylene meltblown nonwoven fabric (purchased from Yanshan Petrochemical, specification 25g / m 2 , fiber diameter 0.5-8 μm) replaces the super-spread polypropylene fiber membrane in Example 1 as the water separation membrane, and the other conditions are the same, and no water flows out of the water channel.

[0139] Comparative Example 2

[0140] The modified polypropylene fiber membrane in Preparation Example 3 was used to replace the super-spread polypropylene fiber membrane in Preparation Example 1 as the water separation membrane. The other conditions were the same as those in Example 1. The test results are shown in Table 2.

[0141] Comparative Example 3

[0142] The modified polypropylene fiber membrane in Preparation Example 4 was used to replace the super-spread polypropylene fiber membrane in Preparation Example 1 in Example 2 as the water separation membrane, and the other conditions were the same as in Example 2. Since the film in Preparation Example 4 could not be spread, the water passage was dry for a long time, and the test results are shown in Table 2.

[0143] Table 1

[0144]

[0145] Table 2

[0146] serial number <![CDATA[Water flux / L / m 2 ·h]]> <![CDATA[Oil flux / L / m 2 ·h]]> Example 1 <![CDATA[7.57×10 4 ]]> <![CDATA[1.21×10 5 ]]> Example 2 <![CDATA[7.58×10 4 ]]> <![CDATA[1.34×10 5 ]]> Example 3 <![CDATA[6.28×10 4 ]]> <![CDATA[1.03×10 5 ]]> Example 4 <![CDATA[6.98×10 4 ]]> <![CDATA[1.15×10 5 ]]> Comparative Example 1 / <![CDATA[1.22×10 4 ]]> Comparative Example 2 / <![CDATA[1.21×10 4 ]]> Comparative Example 3 / <![CDATA[0.83×10 4 ]]>

[0147] From the above embodiments, it can be seen that the oil-water separation device of the present invention realizes efficient separation of oil and water, and broadens the application scope of using membrane materials to realize efficient oil-water separation. The oil-water separation device of the present invention is simple, has high water-oil flux, and has extremely high application value.

[0148] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation to the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein, on the contrary, the present invention can be extended to all other methods and applications with the same functions.

[0149] All publications, patent applications, patents and other references mentioned in this specification are incorporated herein by reference. Unless otherwise defined, all technical and scientific terms used in this specification have the meanings conventionally understood by those skilled in the art. In the event of a conflict, the definition in this specification shall prevail.

[0150] When this specification uses the prefix "well-known to those skilled in the art", "prior art" or similar terms to introduce materials, substances, methods, steps, devices or components, etc., the objects introduced by the prefix cover those conventionally used in the art when the present invention was proposed, but also include those that are not commonly used at present but will become recognized in the art as being suitable for similar purposes.

[0151] The endpoints and any values ​​of the ranges disclosed in the present invention document are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be regarded as specifically disclosed in this article. Hereinafter, in principle, each technical solution can be combined with each other to obtain a new technical solution, which should also be regarded as specifically disclosed in this article.

[0152] In the context of the present specification, any matters or items not mentioned are directly applicable to those known in the art without any changes except those explicitly stated.

[0153] Moreover, any embodiment described in this document may be freely combined with one or more other embodiments described in this document, and the technical solutions or technical ideas formed thereby are deemed to be part of the original disclosure or original record of the present invention, and should not be regarded as new content that has not been disclosed or anticipated in this document, unless a person skilled in the art considers that the combination is obviously unreasonable.

Claims

1. An oil-water separation device, comprising a liquid inlet cavity, the liquid inlet cavity is provided with a liquid inlet, one end of the liquid inlet cavity is provided with a super-spreading polypropylene fiber membrane, and the other end is provided with an oleophilic fiber membrane; The oil-water separation device further comprises a water outlet and an oil outlet, wherein the water outlet is connected to the liquid inlet cavity through the super-spread polypropylene fiber membrane, and the oil outlet is connected to the liquid inlet cavity through the oleophilic fiber membrane; The super-spread polypropylene fiber membrane contains a polypropylene fiber membrane matrix and an amphiphilic polymer. Taking the mass of the super-spread polypropylene fiber membrane as 100%, the content of the polypropylene fiber membrane matrix in the super-spread polypropylene fiber membrane is 93%-99.99%; the content of the amphiphilic polymer is 0.01%-7%.

2. The oil-water separation device according to claim 1, characterized in that: Taking the mass of the super-spread polypropylene fiber membrane as 100%, the content of the polypropylene fiber membrane matrix in the super-spread polypropylene fiber membrane is 95%-99.95%; the content of the amphiphilic polymer is 0.05%-5%; and / or, The super-spread polypropylene fiber membrane is a super-hydrophilic polypropylene fiber membrane without a layered structure; and / or, The content of the amphiphilic polymer per unit surface area of ​​the super-spread polypropylene fiber membrane is 0.005 g / m 2 -3g / m 2 , preferably 0.005g / m 2 -2g / m 2 .

3. The oil-water separation device according to claim 1, characterized in that: The fiber diameter of the super spread polypropylene fiber membrane is below 20 microns, preferably below 10 microns, more preferably 0.1-10 microns; and / or, The amphiphilic polymer is selected from polyvinyl alcohol and / or a cross-linked polymer formed by polyvinyl alcohol and a cross-linking agent; the cross-linking agent is preferably selected from at least one of a polyacid and a polyaldehyde, more preferably glutaraldehyde and / or boric acid; and / or, The super-spread polypropylene fiber membrane contains polypropylene fibers coated with an amphiphilic polymer. Preferably, the amphiphilic polymer is self-assembled and coated on the polypropylene fibers through capillary force.

4. The oil-water separation device according to claim 1, characterized in that: The method for preparing the super-spread polypropylene fiber membrane comprises contacting a polypropylene fiber membrane substrate with a solution containing an amphiphilic polymer under the action of an external force, wherein the content of the amphiphilic polymer in the solution containing the amphiphilic polymer is not higher than 5wt%, and optionally subjecting the polypropylene fiber membrane obtained after the polypropylene fiber membrane substrate is contacted with the amphiphilic polymer to a cross-linking reaction in a solution containing a cross-linking agent to obtain the super-spread polypropylene fiber membrane; preferably, The contacting is carried out in a solution containing an amphiphilic polymer; and / or, The contact utilizes intermolecular forces to cause the amphiphilic polymer to self-assemble on the surface of the polypropylene fiber membrane, thereby obtaining a polypropylene fiber membrane coated with the amphiphilic polymer.

5. The oil-water separation device according to claim 4, characterized in that: The content of the amphiphilic polymer in the solution containing the amphiphilic polymer is 0.05-4.5 wt %, preferably 0.1-4.5 wt %; and / or, The preparation method further comprises a step of drying the polypropylene fiber membrane matrix after contacting the amphiphilic polymer; preferably, The contacting temperature and the drying temperature each do not exceed the melting temperature of the fiber membrane matrix and the amphiphilic polymer, and more preferably do not exceed the glass transition temperature of the amphiphilic polymer.

6. The oil-water separation device according to any one of claims 1 to 5, characterized in that: The super-spread polypropylene fiber membrane has at least one of the following characteristics: The super-spreading polypropylene fiber membrane has a static contact angle of water of 0 degrees within no more than 1 second, preferably within 0.005 seconds to 1 second; and / or, After a droplet with a volume of 2 μL is spread on the super-spread polypropylene fiber membrane, the maximum size of the spreading area is not less than 7 mm, after a droplet with a volume of 5 μL is spread on the super-spread polypropylene fiber membrane, the maximum size of the spreading area is not less than 8 mm, after a droplet with a volume of 8 μL is spread on the super-spread polypropylene fiber membrane, the maximum size of the spreading area is not less than 12 mm, and after a droplet with a volume of 12 μL is spread on the super-spread polypropylene fiber membrane, the maximum size of the spreading area is not less than 15 mm.

7. The oil-water separation device according to any one of claims 1 to 5, characterized in that: The static contact angle between the oleophilic fiber membrane and the oil can be 0°, and / or the oil flux is not less than 1.0×10 5 L / m 2 h; Preferably, the oleophilic fiber membrane is selected from at least one of a polypropylene fiber membrane and a modified polypropylene fiber membrane; and / or, The water flux of the oil-water separation device is not less than 6.0×10 4 L / m 2 h, oil flux is not less than 1.0×10 5 L / m 2 ·h; preferably the water flux is not less than 6.5×10 4 L / m 2 ·h, oil flux is not less than 1.1×10 5 L / m 2 ·h; more preferably, the water flux is not less than 7.0×10 4 L / m 2 ·h, oil flux is not less than 1.2×10 5 L / m 2 ·h.

8. The oil-water separation device according to any one of claims 1 to 5, characterized in that: A first supporting layer is provided on one side or both sides of the super-spread polypropylene fiber membrane; preferably, the water flux of the first supporting layer is not less than that of the super-spread polypropylene fiber membrane; and / or, A second supporting layer is provided on one or both sides of the oleophilic fiber membrane, and preferably, the oil flux of the second supporting layer is not less than that of the oleophilic fiber membrane; and / or, The super-spread polypropylene fiber membrane and the oleophilic fiber membrane are respectively connected to the cavity wall of the liquid inlet cavity through a sealing component.

9. A method for oil-water separation using the oil-water separation device according to any one of claims 1 to 8, comprising: Firstly, the super spread polypropylene fiber membrane is moistened with water; Then the oil-water mixture is transported from the liquid inlet to the liquid inlet cavity, the water phase in the oil-water mixture passes through the super-spreading polypropylene fiber membrane and flows out from the water outlet, and the oil phase in the oil-water mixture passes through the oleophilic fiber membrane and flows out from the oil outlet; preferably, The oil-water separation process is negative pressure driven and / or gravity driven.

10. Use of the oil-water separation device according to any one of claims 1 to 8 or the method according to claim 9 in the field of oil-water separation treatment.

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