Oil-water separation component and preparation method thereof, oil-water separator

Abstract

The present invention relates to the technical field of polymer materials, and specifically to an oil-water separation component and a preparation method thereof, and an oil-water separator. The oil-water separation component is assembled from a plurality of oil-water separation materials, and the ratio of the distance between two adjacent oil-water separation materials to the thickness of the oil-water separation material is 1-10:1; wherein the oil-water separation material is a porous material, and the porous material is a polypropylene material with a plurality of micro-nano structures on the surface and inside, and the micro-nano structures are grafted with oleophilic side groups; wherein, on the cross section of the porous material, the surface grafting rate of the oleophilic side groups is 20-60wt%. The present invention limits the oil-water separation component to contain a plurality of oil-water separation materials, so that the oil-water separation component composed of the porous material has a high oil-water separation efficiency and stable performance; at the same time, the structure of the oil-water separation component is simple and easy to install, and there is no need to frequently replace parts.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and in particular to an oil-water separation component and a preparation method thereof, and an oil-water separator. Background Art

[0002] Oil-water separation materials have been widely studied due to their economical, maneuverable, high oil absorption efficiency, and low environmental hazards. Traditional adsorptive oil-water separation materials have drawbacks such as low superhydrophobicity, low separation efficiency, and difficulty in recycling.

[0003] CN112829410A discloses a high-efficiency oil-water separation filter membrane, which is composed of a surface layer, a core layer and a bottom layer arranged in sequence. The surface layer material and the bottom layer material are both hydrophobic materials, and the core layer material is a hydrophilic material; wherein the hydrophobic material is a conventional hydrophobic non-woven material or a hydrophobic material treated with a hydrophobic finishing agent, for example, polypropylene, polyester, hydrophobic ES or SMS composite materials; the hydrophilic material is a non-woven material with good hydrophilic water absorption, for example, cotton, viscose, or hydrophilic ES.

[0004] CN111235959A discloses a multi-layer oil-water separation material, which includes at least a coalescence layer 1 and a coalescence layer 2. The coalescence layer 1 is a hydrophilic-hydrophobic fiber mixed layer, including hydrophilic fibers and at least one fiber selected from hydrophobic fibers and adhesive fibers. The coalescence layer 2 is a hydrophobic fiber layer, including at least one of hydrophobic fibers and adhesive fibers.

[0005] CN102794113A discloses a super-hydrophobic-super-oleophilic polymer porous membrane, comprising 30-99 wt% of a polymer material and 0.01-70 wt% of a small molecule substance; wherein the surface of the porous membrane is a porous rough structure with micro-nano dimensions, and micro-nano and / or micro-nano or submicron pores are distributed inside; the polymer material is selected from at least one of polyvinylidene fluoride, polypropylene, polystyrene and polyethersulfone; and the small molecule substance is selected from at least one of water, sodium hydroxide, ethanol and acetone.

[0006] The above-mentioned oil-water separation materials have the disadvantages of low hydrophobicity, low separation efficiency, and difficulty in recycling; the preparation of oil-water molecular materials has the disadvantages of complex process, long processing cycle, requiring specific equipment, harsh process conditions or expensive low surface energy materials, high energy consumption and cannot be produced on a large scale.

[0007] Therefore, there is an urgent need for a new oil-water separation component and a preparation method thereof. Summary of the Invention

[0008] The purpose of the present invention is to overcome the problems of low hydrophobicity, low separation efficiency, and difficulty in recycling of existing oil-water separation materials, as well as the complex process, long processing cycle, requirement of specific equipment, and harsh process conditions in the preparation of oil-water separation materials. An oil-water separation component and its preparation method, and an oil-water separator are provided. The oil-water separation component has a high oil-water separation efficiency. At the same time, the method is simple, easy to operate, low in cost, and easy to industrialize.

[0009] In order to achieve the above object, the first aspect of the present invention provides an oil-water separation component, which is assembled from a plurality of oil-water separation materials, wherein the ratio of the distance between two adjacent oil-water separation materials to the thickness of the oil-water separation materials is 1-10:1;

[0010] The oil-water separation material is a porous material, and the porous material is a polypropylene material having a plurality of micro-nano structures on the surface and inside, and the micro-nano structures are grafted with oleophilic side groups;

[0011] Wherein, on the cross section of the porous material, the surface grafting rate of the oleophilic side groups is 20-60 wt%.

[0012] A second aspect of the present invention provides a method for preparing an oil-water separation component, the method comprising the following steps:

[0013] (1) contacting a polypropylene material with an etchant and performing a first drying process to form a plurality of micro-nano structures on the surface and inside of the polypropylene material to obtain a modified polypropylene material;

[0014] (2) mixing the modified polypropylene material, a monomer having oleophilic side groups, and an inorganic microwave absorbing medium, and subjecting the resulting mixture to microwave irradiation to graft oleophilic side groups onto the micro-nanostructure of the modified polypropylene material, and using the resulting porous material as an oil-water separation material;

[0015] (3) assembling a plurality of the oil-water separation materials to obtain an oil-water separation assembly;

[0016] Wherein, the ratio of the distance between two adjacent oil-water separation materials to the thickness of the oil-water separation material is 1-10:1;

[0017] Wherein, on the cross section of the porous material, the surface grafting rate of the oleophilic side groups is 20-60 wt%.

[0018] The third aspect of the present invention provides an oil-water separator, which includes: a feed inlet, an oil outlet, at least one water outlet, and at least one oil-water separation component, wherein the oil-water separation component is the oil-water separation component provided by the first aspect, or the oil-water separation component prepared by the method provided by the second aspect.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] (1) The oil-water separation component provided by the present invention is defined as containing multiple oil-water separation materials, that is, porous materials, and further defined as a polypropylene material having multiple micro-nano structures on the surface and inside, and the micro-nano structures are grafted with oleophilic side groups, so that the porous material has a larger water contact angle and a smaller white oil contact angle while ensuring that the mechanical properties are not affected, thereby effectively improving the oil-water separation efficiency of the oil-water separation component composed of the porous material and maintaining stable performance, that is, the oil-water separation component has a higher water retention rate and white oil flux; at the same time, the oil-water separation component has a simple structure and is easy to install, without the need for frequent replacement of parts;

[0021] (2) The method provided by the present invention combines physical modification (etching) and chemical modification (grafting), which can effectively improve the hydrophobicity of the porous material and achieve super-hydrophobicity. Specifically, the polypropylene material is first etched with an etchant, and then the modified polypropylene material, a monomer having an oleophilic side group, and an inorganic microwave absorbing medium are subjected to microwave irradiation without adding a grafting initiator to graft the oleophilic side group on the modified polypropylene material. The porous material is then combined with an assembly method of using the porous material as an oil-water separation material, so that the oil-water separation component has a high oil-water separation efficiency. At the same time, the method is simple in process, easy to operate, and convenient for industrial large-scale production.

[0022] (3) The oil-water separator provided by the present invention further improves the oil-water separation efficiency by limiting the number of oil-water separation components in the oil-water separator, especially limiting the distance between two adjacent oil-water separation components. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a SEM image of the cross section S1 of the porous material prepared in Example 1;

[0024] Figure 2 is a distribution diagram of oleophilic side groups (Si element) of the cross section S1 of the porous material prepared in Example 1;

[0025] Figure 3 It is a structural schematic diagram of an oil-water separator provided by the present invention. DETAILED DESCRIPTION

[0026] The endpoints of the ranges and any values ​​disclosed herein 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 endpoints of each range, the endpoints of each range and 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 considered to be specifically disclosed herein.

[0027] In the present invention, unless otherwise specified, the "first", "second" and "third" do not indicate a sequence, nor do they limit the materials or steps. They are only used to distinguish the same material or step. For example, the "first", "second" and "third" in "first drying", "second drying" and "third drying" are only used to distinguish that they are not the same drying; the "first" and "second" in "first solvent" and "second solvent" are only used to distinguish that they are not the same solvent.

[0028] A first aspect of the present invention provides an oil-water separation component, which is assembled from a plurality of oil-water separation materials, wherein the ratio of the distance between two adjacent oil-water separation materials to the thickness of the oil-water separation materials is 1-10:1;

[0029] The oil-water separation material is a porous material, and the porous material is a polypropylene material having a plurality of micro-nano structures on the surface and inside, and the micro-nano structures are grafted with oleophilic side groups;

[0030] Wherein, on the cross section of the porous material, the surface grafting rate of the oleophilic side groups is 20-60 wt%.

[0031] In the present invention, unless otherwise specified, the micro-nano structure refers to burrs and / or holes having micrometer or nanometer scale characteristic dimensions and arranged in a specific manner; the burrs are protrusions, and the holes are grooves.

[0032] In the present invention, unless otherwise specified, the cross section of the porous material is prepared by freezing the porous material in liquid nitrogen for 1 minute to ensure that the micro-nanostructure is frozen, and then taking it out and cutting out the cross section using a Leica cryo-ultra-thin slicer.

[0033] The porous material provided by the present invention is a polypropylene material with multiple micro-nano structures on the surface and inside. The micro-nano structures are grafted with oleophilic side groups, which are used to collect passing oil droplets and intercept water droplets, further improving the oil-water separation efficiency of the porous material.

[0034] Therefore, the porous material provided by the present invention is more hydrophobic than the polypropylene material, and even achieves super-hydrophobic properties. At the same time, the porous material provided by the present invention does not reduce the molecular weight of the polypropylene material, has no residual monomers with oleophilic side groups, does not introduce initiators, is colorless and odorless, and has greatly improved hydrophobicity and is long-lasting and stable.

[0035] The porous material provided by the present invention possesses hydrophobicity, even super-hydrophobicity, enabling oil-water separation when an oil-water mixture flows downward through the porous material. The porous material allows the oil component of the mixture to pass through, while the water is trapped above the porous material and discharged through a drain valve. An oil-water separation assembly assembled using this porous material has high separation efficiency and a simple structure, eliminating the need for frequent component replacement.

[0036] In some embodiments of the present invention, preferably, the oil-water separation component is formed by assembling a plurality of the oil-water separation materials in parallel, wherein the oil-water separation material is the porous material provided by the present invention.

[0037] In the present invention, in order to improve the separation efficiency of the oil-water mixture, multiple oil-water separation materials need to be provided. In the oil-water separation assembly, the number of the oil-water separation materials is ≥ 2, preferably 2-3.

[0038] In some embodiments of the present invention, preferably, the ratio of the distance between two adjacent oil-water separation materials to the thickness of the oil-water separation materials is 1-10:1, for example, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, and any value within a range consisting of any two of these values, preferably 2-8:1. Using these preferred conditions is more conducive to improving the separation efficiency of the oil-water separation assembly.

[0039] In some embodiments of the present invention, the porosity of the porous material is preferably 60-95%, for example, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or any value within a range consisting of any two of these values, preferably 75-90%. Using these preferred conditions is more conducive to improving the oil-water separation efficiency of the porous material, that is, increasing the water retention rate and white oil flux.

[0040] In some embodiments of the present invention, preferably, the porous material has pores running through from top to bottom, and the average diameter of the pores is 10-100 μm, for example, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, and any value in the range consisting of any two values, preferably 20-60 μm.

[0041] In the present invention, the porous material is hydrophobic or even superhydrophobic, i.e., the water contact angle of the porous material cross section is greater than that of polypropylene. Preferably, the water contact angle of the porous material cross section is ≥150°, preferably 150-180°; the white oil contact angle is ≤30°, preferably 0-10°.

[0042] According to the present invention, preferably, the water retention rate of the porous material is 80-100%, preferably 90-100%; the white oil flux is 250-1000 L / m 2 h, preferably 300-500 L / m 2 ·h.

[0043] In the present invention, unless otherwise specified, the water contact angle parameters are measured using the EASY DROP contact angle tester from KRUSS, Germany, with a measurement range of 1-180° and a resolution of ±0.1°. The dynamic contact angle measurement mode is adopted, and a fixed volume of 2 μL of deionized water droplets is dropped on the cross section of the porous material each time. The calculated initial contact angle is taken as the measured water contact angle value of the cross section of the porous material. The measurements are performed in parallel 6 times, and the average value is calculated.

[0044] In the present invention, unless otherwise specified, the white oil contact angle parameters are measured using the EASYDROP contact angle tester from KRUSS, Germany, with a measurement range of 1-180° and a resolution of ±0.1°. A dynamic contact angle measurement mode is used, and a white oil droplet with a fixed volume of 2 μL is dropped on the cross section of the porous material each time. The calculated initial contact angle is taken as the measured white oil contact angle value of the porous material cross section. Six parallel measurements are performed to calculate the average value.

[0045] In the present invention, unless otherwise specified, the white oil flux parameters and water retention rate parameters are measured using a constant pressure vacuum filtration system.

[0046] In the present invention, unless otherwise specified, the water retention rate parameter test is as follows: 5 mL of alkane reagent is added to 100 mL of deionized water containing a surfactant and ultrasonicated for 20 minutes to form a stable oil-in-water emulsion; the test pressure is 0.09 MPa, the test temperature is 25°C, the sample size is 4 cm in diameter, and the effective area is 12.56 cm 2 The testing time for all samples must be more than 50 minutes, and each group of samples must be tested at least 5 times; the organic carbon content in the solution before and after separation is measured by TOC.

[0047] In the present invention, the water retention rate parameter calculation formula is: R% = C p / C f × 100%, where C p and C f are the organic carbon concentrations in the feed solution and the filtrate, respectively.

[0048] In the present invention, unless otherwise specified, the white oil flux parameter test is as follows: the test pressure is 0.09 MPa, the test temperature is 25°C, the sample size is 4 cm in diameter, and the effective area is 12.56 cm 2 , the testing time for all samples must be more than 5 minutes, and each group of samples must be tested at least 5 times.

[0049] In the present invention, the white oil flux parameter calculation formula is: J = V / (A·t), where J is the white oil flux, L / (m 2 ·h); V is the volume of permeate, m 3 ; A is the effective area of ​​the sample, m 2 ; t is the effective time of the sample being tested, h.

[0050] In some embodiments of the present invention, preferably, the polypropylene material is a foamed polypropylene material.

[0051] In some embodiments of the present invention, preferably, the surface average pore size of the foamed polypropylene material is 10-100 μm, for example, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, and any value in a range consisting of any two numerical values, preferably 20-60 μm; the flexural strength is 0.1-1 MPa, for example, 0.1 MPa, 0.2 MPa, 0.3 MPa, 0.4 MPa, 0.5 MPa, 0.7 MPa, 0.9 MPa, 1 MPa, and any value in a range consisting of any two numerical values, preferably 0.1-0.5 MPa; the thickness is 0.1-1 cm, for example, 0.1 cm, 0.2 cm, 0.3 cm, 0.4 cm, 0.5 cm, 0.8 cm, 1 cm, and any value in a range consisting of any two numerical values, preferably 0.1-0.5 cm. Adopting the preferred conditions is more conducive to forming projections and / or grooves with greater length and depth on the surface and inside of the polypropylene material.

[0052] In the present invention, unless otherwise specified, the surface average pore size parameter is measured by the statistical average method of three surface scans using a scanning electron microscope; the bending strength parameter is measured by the GB / T 9341-2008 polypropylene three-point bending test method; and the thickness parameter is measured by the vernier caliper test method.

[0053] In some embodiments of the present invention, the foamed polypropylene material is preferably foamed from at least one selected from a homopolymer polypropylene material having a polypropylene content of ≥50 wt%, a random copolymer polypropylene material, and an impact copolymer polypropylene material. In the present invention, the foaming process has a wide range of options, and the material can be produced by chemical foaming or physical foaming.

[0054] In the present invention, the source of the foamed polypropylene material has a wide range of choices, as long as the polypropylene material is prepared by foaming. In the present invention, the foamed polypropylene material can be obtained by purchase or preparation, and the present invention will not go into details here.

[0055] In a preferred embodiment of the present invention, the foamed polypropylene material is prepared by foaming a polypropylene material using supercritical carbon dioxide.

[0056] In some embodiments of the present invention, preferably, the content of polypropylene in the foamed polypropylene material is ≥50 wt%, preferably 50-90 wt%.

[0057] In some embodiments of the present invention, preferably, the weight average molecular weight of the polypropylene is 10 4 -10 6 g / mol; the melt index at 230°C and a load of 2.16 kg is 0.1-15 g / 10 min, for example, 0.1 g / 10 min, 1 g / 10 min, 2 g / 10 min, 3 g / 10 min, 4 g / 10 min, 5 g / 10 min, 6 g / 10 min, 7 g / 10 min, 10 g / 10 min, 15 g / 10 min, and any value in a range consisting of any two values, preferably 1-7 g / 10 min.

[0058] In the present invention, unless otherwise specified, the melt index parameters are measured by the GB / T3682.1-2018 method.

[0059] In some embodiments of the present invention, preferably, the length of each of the micro-nanostructures is 1 nm-100 μm, for example, 1 nm, 10 nm, 100 nm, 200 nm, 500 nm, 1 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 100 μm, and any value in a range consisting of any two values, preferably 500 nm-50 μm; the depth is 1 μm-1 mm, for example, 1 μm, 10 μm, 50 μm, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 400 μm, 500 μm, 700 μm, 900 μm, 1 mm, and any value in a range consisting of any two values, preferably 50-500 μm. In the present invention, the micro-nano structure is beneficial to the improvement of the wettability of the material. For example, when the flat surface is hydrophobic (>90°), the surface with the micro-nano structure has a capillary effect on water, and the capillaries running through the upper and lower surfaces can further infiltrate water, thereby showing a more hydrophobic or even super-hydrophobic state.

[0060] In some embodiments of the present invention, preferably, the surface grafting rate of the oleophilic side groups in the porous material is 20-60 wt %, for example, 20 wt %, 30 wt %, 40 wt %, 50 wt %, 60 wt %, or any value within a range consisting of any two of these values, preferably 30-60 wt %. Adopting these preferred conditions is more conducive to improving the hydrophobicity of the porous material.

[0061] In the present invention, unless otherwise specified, the surface grafting rate parameter is measured using the energy spectrum accessory of the S4800 scanning electron microscope of Hitachi, Japan, to measure the content of the main elements (e.g., Si element) of the grafted components of the porous material, and the content of the grafted material on the surface of the porous material is inferred from the molecular formula of the grafted material as the surface grafting rate.

[0062] In the present invention, the lipophilic side groups have a wide range of choices, as long as the lipophilic side groups contain hydrophobic groups. Preferably, the lipophilic side groups are selected from vinyl silicone oil-containing side groups and / or styrene-containing side groups, preferably vinyl silicone oil-containing side groups.

[0063] In some embodiments of the present invention, preferably, the monomer having an oleophilic side group is a vinyl-terminated silicone oil and / or a high-vinyl silicone oil, preferably at least one selected from vinyl silicone oil, methyl vinyl silicone oil, vinyl hydrogen silicone oil and divinyl silicone oil.

[0064] According to a particularly preferred embodiment of the present invention, the oil-water separation component is formed by assembling a plurality of oil-water separation materials in parallel, and the ratio of the distance between two adjacent oil-water separation materials to the thickness of the oil-water separation materials is 2-8:1;

[0065] The oil-water separation material is a porous material, and the porous material is a polypropylene material having a plurality of micro-nano structures on the surface and inside, and the micro-nano structures are grafted with oleophilic side groups;

[0066] Wherein, on the cross section of the porous material, the surface grafting rate of the oleophilic side groups is 30-60 wt%; the porosity of the porous material is 75-90%;

[0067] Wherein, the polyolefin material is foamed polypropylene material;

[0068] The average pore size of the foamed polypropylene material is 10-100 μm; the bending strength is 0.1-1 MPa; and the thickness is 0.1-1 cm.

[0069] The porous material is prepared by the following method: contacting a polypropylene material with an etchant and performing a first drying to form a plurality of micro-nano structures on the surface and inside of the polypropylene material to obtain a modified polypropylene material; mixing the modified polypropylene material, a monomer having oleophilic side groups, and an inorganic microwave absorbing medium, and subjecting the obtained mixture to microwave irradiation to graft oleophilic side groups onto the micro-nano structures of the modified polypropylene material.

[0070] A second aspect of the present invention provides a method for preparing a porous material, the method comprising the following steps:

[0071] (1) contacting a polypropylene material with an etchant and performing a first drying process to form a plurality of micro-nano structures on the surface and inside of the polypropylene material to obtain a modified polypropylene material;

[0072] (2) mixing the modified polypropylene material, a monomer having oleophilic side groups, and an inorganic microwave absorbing medium, and subjecting the resulting mixture to microwave irradiation to graft oleophilic side groups onto the micro-nanostructure of the modified polypropylene material, and using the resulting porous material as an oil-water separation material;

[0073] (3) assembling a plurality of the oil-water separation materials to obtain an oil-water separation assembly;

[0074] Wherein, the ratio of the distance between two adjacent oil-water separation materials to the thickness of the oil-water separation material is 1-10:1;

[0075] Wherein, on the cross section of the porous material, the surface grafting rate of the oleophilic side groups is 20-60 wt%.

[0076] The inventors of the present invention have discovered that etching a polypropylene material with an etchant, particularly soaking and etching a foamed polypropylene material with a microporous structure, imparts a greater number of micro-nanostructures to the surface and interior of the polypropylene material, rendering the polypropylene material super-hydrophobic. Furthermore, a grafting reaction is performed with a lipophilic side-group monomer and an inorganic microwave absorbing medium using microwave irradiation without the addition of an initiator, thereby preparing a porous material exhibiting both super-hydrophobicity and super-lipophilicity. The microwave absorbing medium absorbs microwaves, heating the material to 200°C or higher under microwave irradiation, and generating free radicals. Simultaneously, the high temperature also triggers the generation of free radicals in nearby polypropylene molecular chains, allowing the lipophilic side-group monomer to fully graft onto the polypropylene, thereby producing a grafted polypropylene surface. Since the polarity of lipophilic side group monomers (for example, vinyl silicone oil side group monomers) is relatively low, they cannot reach a very high temperature when absorbing microwaves under microwave irradiation (the temperature in the microwave field rises to less than 200°C), and thus cannot effectively trigger the polypropylene molecular chain to produce free radicals. Therefore, it is necessary to add an inorganic microwave absorbing medium to help polypropylene generate free radicals and then undergo a grafting reaction with the lipophilic side group monomers (for example, vinyl silicone oil side group monomers). The inorganic microwave absorbing medium does not react with the polypropylene surface and monomers. As a heat source for the grafting reaction, it does not affect the surface properties of the polypropylene. The addition of the inorganic microwave absorbing medium can help monomers that do not absorb microwaves to be grafted onto polypropylene; for monomers that absorb microwaves themselves, it can help improve their grafting efficiency.

[0077] Therefore, the present invention utilizes selective heating of an inorganic microwave absorbing medium. The medium can be heated under microwave conditions to temperatures above 200°C, near the melting point of polypropylene. At this temperature, polypropylene chains are not broken, but tertiary carbons in polypropylene can be dehydrogenated, resulting in a grafting reaction without chain scission. Grafting monomers with oleophilic side groups (e.g., vinyl silicone oil side groups) further enhances the hydrophobicity of the polypropylene material, resulting in a porous material with even stronger hydrophobicity. Because the polypropylene material has a micro-nanostructure, capillary action renders the porous material super-hydrophobic.

[0078] In the present invention, in step (1), the types of the polypropylene material are in accordance with the above-mentioned limitations, and the present invention will not elaborate on this.

[0079] In some embodiments of the present invention, preferably, in step (1), the weight ratio of the polypropylene material to the etchant is 0.01-10:100, for example, 0.01:100, 0.1:100, 1:100, 2:100, 3:100, 4:100, 5:100, 8:100, 10:100, and any value in a range consisting of any two values, preferably 0.01-5:100. The preferred weight ratio allows the etchant to uniformly immerse the entire structure of the polypropylene material, which is more conducive to sufficient contact and mixing between the two, thereby facilitating the formation of micro-nano structures on the surface and inside the polypropylene material.

[0080] In the present invention, the type of the etchant has a wide range of options, as long as it can immerse and etch the surface of the polypropylene material. Preferably, the etchant is a polar organic solvent, preferably at least one selected from toluene, xylene, diphenyl ether, butyl acetate, isoamyl acetate, n-heptane, n-octane, and decalin.

[0081] In the present invention, the contact conditions have a wide range of options. Preferably, the contact conditions include: a temperature of 15-70°C, preferably 20-60°C; and a time of 1-24 hours, preferably 5-15 hours.

[0082] In the present invention, there is a wide range of options for the contact method. Preferably, the contact method is immersion; that is, the polypropylene material is immersed in the etchant, wherein the immersion temperature is 15-70° C. and the immersion time is 1-24 hours.

[0083] In the present invention, the first drying is intended to remove the etchant in the contact product. Preferably, the first drying conditions include: a temperature of 80-120°C, preferably 80-100°C; and a time of 1-10 hours, preferably 1-5 hours.

[0084] In some embodiments of the present invention, preferably, in step (2), the weight ratio of the monomer to the modified polypropylene material is 40-70:100, for example, 40:100, 45:100, 50:100, 55:100, 60:100, 65:100, 70:100, and any value in a range consisting of any two of these values, preferably 50-70:100. The preferred weight ratio facilitates thorough mixing of the raw materials and grafting reaction, thereby increasing the surface grafting rate of the monomer having oleophilic side groups in the porous material.

[0085] In some embodiments of the present invention, preferably, the monomer is selected from vinyl-terminated silicone oil and / or high-vinyl silicone oil, preferably selected from at least one of vinyl silicone oil, methyl vinyl silicone oil, vinyl hydrogen silicone oil and divinyl silicone oil.

[0086] In the present invention, the monomer having oleophilic side groups can be directly added to the modified propylene material for mixing, or for better mixing effect, preferably, the monomer exists in the form of a solution, that is, a solution containing the monomer is used for mixing.

[0087] In some embodiments of the present invention, preferably, in the monomer-containing solution, the weight ratio of the monomer to the first solvent is 0.1-100:100, for example, 0.1:100, 0.5:100, 1:100, 2:100, 3:100, 5:100, 10:100, 20:100, 30:100, 40:100, 50:100, 80:100, 100:100, and any value in a range consisting of any two values, preferably 0.5-50:100, more preferably 1-30:100. This preferred weight ratio can better ensure that the monomer in the monomer-containing solution can completely cover the modified polypropylene material, facilitating sufficient mixing of the two.

[0088] In the present invention, a wide range of choices is available for the first solvent, as long as the monomer having lipophilic side groups is dissolved in the first solvent. Preferably, the first solvent is selected from water and / or an organic solvent, preferably at least one selected from alcohols, ketones, esters, and water, and more preferably acetone and / or ethanol.

[0089] In the present invention, the inorganic microwave absorbing medium can be any of various inorganic materials that can absorb microwaves in the prior art. Preferably, the inorganic microwave absorbing medium is selected from at least one of metal hydroxides, metal salts, metal oxides, graphite materials, ferroelectric materials, electrolytic stone, and chalcopyrite.

[0090] In some embodiments of the present invention, preferably, the metal hydroxide is selected from at least one of potassium hydroxide, barium hydroxide, sodium hydroxide, lithium hydroxide, strontium hydroxide, calcium hydroxide, ferric hydroxide, ferrous hydroxide, zinc hydroxide, magnesium hydroxide, cobalt hydroxide, gold hydroxide, aluminum hydroxide, copper hydroxide, beryllium hydroxide and rare earth hydroxides.

[0091] In some embodiments of the present invention, preferably, the metal salt is selected from at least one of nitrates, chlorates, sulfates, carbonates, phosphates and titanates, and is preferably selected from at least one of ammonium nitrate, potassium nitrate, sodium nitrate, barium nitrate, calcium nitrate, magnesium nitrate, aluminum nitrate, manganese nitrate, zinc nitrate, ferric nitrate, ferrous nitrate, copper nitrate, silver nitrate, ammonium chloride, potassium chloride, sodium chloride, barium chloride, calcium chloride, magnesium chloride, aluminum chloride, manganese chloride, zinc chloride, ferric chloride, ferrous chloride, cupric chloride, ammonium sulfate, potassium sulfate, sodium sulfate, calcium sulfate, magnesium sulfate, aluminum sulfate, manganese sulfate, zinc sulfate, ferric sulfate, ferrous sulfate, copper sulfate, silver sulfate, ammonium carbonate, potassium carbonate, sodium carbonate, magnesium carbonate, calcium carbonate, barium carbonate, potassium dihydrogen phosphate, barium titanate, strontium titanate and calcium copper titanate.

[0092] In some embodiments of the present invention, preferably, the metal oxide is selected from ferrous oxide and / or ferrosoferric oxide.

[0093] In some embodiments of the present invention, preferably, the graphite material is selected from at least one of carbon black, graphite powder, graphene, carbon nanotubes and activated carbon.

[0094] In some embodiments of the present invention, the weight ratio of the inorganic microwave absorbing medium to the modified polypropylene material is preferably 10-50:100, for example, 10:100, 15:100, 20:100, 25:100, 30:100, 35:100, 40:100, 45:100, 50:100, and any value within a range consisting of any two of these values, preferably 20-30:100. This preferred weight ratio allows the inorganic microwave absorbing medium to completely cover the modified polypropylene material mixture, facilitating thorough mixing of the raw materials and the grafting reaction.

[0095] In the present invention, unless otherwise specified, the weight of the inorganic microwave absorbing medium refers to the single usage of the inorganic microwave absorbing medium.

[0096] In the present invention, the inorganic microwave absorbing medium can be directly added to the modified polypropylene material for mixing, or for better mixing effect, preferably, the inorganic microwave absorbing medium exists in the form of a solution / dispersion, that is, the solution / dispersion containing the inorganic microwave absorbing medium is used for mixing.

[0097] In some embodiments of the present invention, preferably, in the solution / dispersion containing the inorganic microwave absorbing medium, the weight ratio of the inorganic microwave absorbing medium to the second solvent is 0.1-100:100, for example, 0.1:100, 0.5:100, 1:100, 2:100, 3:100, 5:100, 10:100, 20:100, 30:100, 40:100, 50:100, 80:100, 100:100, and any value in the range consisting of any two values, preferably 0.5-50:100, and more preferably 1-30:100.

[0098] In the present invention, the second solvent has a wide range of options, as long as the inorganic microwave absorbing medium is dissolved in the second solvent or the inorganic microwave absorbing medium is uniformly dispersed therein to form a solution / dispersion. Preferably, the second solvent is selected from water and / or an organic solvent, preferably at least one selected from alcohols, ketones, esters, and water, and more preferably selected from alcohols and / or water.

[0099] In the present invention, to ensure that the inorganic microwave absorbing medium can form a stable solution / dispersion with the second solvent, a surfactant can be added to the solution / dispersion containing the inorganic microwave absorbing medium. Preferably, the surfactant is selected from a polyoxyethylene surfactant and / or a polyol surfactant.

[0100] In some embodiments of the present invention, preferably, the solution / dispersion containing the inorganic microwave absorbing medium further contains a surfactant; further preferably, the solution / dispersion containing the inorganic microwave absorbing medium further contains a surfactant, and the weight ratio of the surfactant to the inorganic microwave absorbing medium is 0.1-100:100, for example, 0.1:100, 0.5:100, 1:100, 5:100, 10:100, 15:100, 20:100, 30:100, 40:100, 50:100, 80:100, 100:100, and any value in the range consisting of any two values, preferably 0.5-50:100, and more preferably 1-20:100.

[0101] In the present invention, the mixing method has a wide range of options, as long as the components in the mixture are mixed uniformly. For example, the mixing method can be coating, dripping, immersion covering, etc., which are not described in detail in the present invention.

[0102] In the present invention, the microwave irradiation conditions have a wide range of options, as long as the monomers with oleophilic side groups are grafted onto the modified polypropylene material. Preferably, the microwave irradiation conditions include: an irradiation power of 1500-27000W, preferably 1500-15000W; and an irradiation time of 1 second to 1 minute, preferably 1-30 seconds.

[0103] In the present invention, unless otherwise specified, the microwave irradiation is carried out in various microwave reactors available in the prior art.

[0104] In some embodiments of the present invention, preferably, in step (3), the assembling method includes: assembling a plurality of the porous materials in parallel to obtain an oil-water separation component.

[0105] In the present invention, in order to remove the solvent from the mixture, preferably, the mixture is subjected to a second drying process before the microwave irradiation. Further preferably, the second drying process is performed at a temperature of 80-120°C, preferably 80-100°C, and for a time of 1-10 hours, preferably 1-5 hours.

[0106] According to the present invention, preferably, the method further comprises: washing the microwave irradiated product to remove unreacted monomers and / or inorganic microwave absorbing medium that does not participate in the reaction in the microwave irradiated product; or, washing the microwave irradiated product after reacting it with a base.

[0107] In some embodiments of the present invention, the microwave irradiated product is immediately soaked in a cleaning liquid having a volume exceeding that of the microwave irradiated product at high temperature, and then excess water is removed using a filtering device; the washing is repeated 2-6 times to obtain a clean microwave irradiated product.

[0108] In the present invention, the cleaning liquid has a wide range of choices. Preferably, the cleaning liquid is selected from water and / or an organic solvent, preferably at least one selected from alcohol, ketone, ester and water, more preferably alcohol and / or water.

[0109] In some embodiments of the present invention, the method preferably further comprises: subjecting the washed product to a third drying step. In the present invention, the third drying step can be performed by forced air drying or room temperature drying, which is not described in detail herein. The third drying step preferably takes place at a temperature not exceeding 160°C to avoid melting the polypropylene material.

[0110] A third aspect of the present invention provides an oil-water separator, the oil-water separator comprising: a feed inlet, an oil outlet, at least one water outlet, and at least one oil-water separation component;

[0111] Wherein, the oil-water separation component is the oil-water separation component provided in the first aspect, or the oil-water separation component manufactured by the method provided in the second aspect.

[0112] According to the present invention, preferably, two adjacent oil-water separation components are arranged in parallel inside the oil-water separator at a distance of 10-30 cm.

[0113] According to the present invention, preferably, the number of the water outlets is the same as the number of the oil-water separation components, and each is independently ≥2, preferably 2-3.

[0114] According to the present invention, preferably, the water outlet is arranged at the upper part of the oil-water separation component, and the height difference between the water outlet and the oil-water separation component is ≤0.5 cm, preferably 0-0.5 cm.

[0115] The structural diagram of an oil-water separator provided by the present invention is as follows Figure 3 As shown by Figure 3 It can be seen that the oil-water separator includes: a feed port, an oil outlet, three water outlets, and three oil-water separation components; wherein, two adjacent oil-water separation components are arranged in parallel inside the oil-water separator with a spacing of 10-30 cm; the water outlet is arranged at the upper part of the oil-water separation component, and the height difference between the water outlet and the oil-water separation component is 0 cm; wherein, the oil-water separation component is assembled from multiple oil-water separation materials, and the ratio of the spacing between two adjacent oil-water separation materials to the thickness of the oil-water separation material is 1-10:1; wherein, the oil-water separation material is the porous material provided by the present invention.

[0116] The present invention will be described in detail below through examples.

[0117] Preparation of porous material cross section: The porous material was placed in liquid nitrogen and frozen for 1 minute to ensure that the micro-nanostructure was frozen. After taking it out, a Leica cryo-ultra-thin slicer was used to cut out the cross-section plane.

[0118] The water contact angle parameters were measured using the EASY DROP contact angle tester from KRUSS, Germany, with a measurement range of 1-180° and a resolution of ±0.1°. The dynamic contact angle measurement mode was used, and a fixed volume of 2 μL of deionized water droplet was dropped on the cross section of the porous material each time. The calculated initial contact angle was taken as the measured water contact angle value of the porous material cross section. The measurements were repeated 6 times in parallel, and the average value was calculated.

[0119] The white oil contact angle parameters were measured using the EASY DROP contact angle tester from KRUSS, Germany, with a measurement range of 1-180° and a resolution of ±0.1°. The dynamic contact angle measurement mode was used, and a fixed volume of 2 μL of white oil droplet was dropped on the cross section of the porous material each time. The calculated initial contact angle was taken as the measured white oil contact angle value of the porous material cross section. Six parallel measurements were performed, and the average value was calculated.

[0120] The surface grafting rate parameter was measured by the energy spectrum accessory of Hitachi S4800 scanning electron microscope to measure the content of the main element (Si element) of the grafted component in the cross section of the porous material, and the content of the grafted material in the cross section of the porous material was inferred from the molecular formula of the grafted material as the grafting rate.

[0121] The white oil flux parameters and water retention rate parameters were measured using a constant pressure vacuum filtration system.

[0122] Water retention parameter test: 5 mL of alkane reagent was added to 100 mL of deionized water containing a surfactant and ultrasonicated for 20 minutes to form a stable oil-in-water emulsion; the test pressure was 0.09 MPa, the test temperature was 25°C, the sample size was 4 cm in diameter, and the effective area was 12.56 cm 2 The testing time for all samples must be more than 50 minutes, and each group of samples must be tested at least 5 times; the organic carbon content in the solution before and after separation is measured by TOC.

[0123] Water retention rate parameter calculation formula: R% = C p / C f × 100%, where C p and C f are the organic carbon concentrations in the feed solution and the filtrate, respectively.

[0124] White oil flux parameter test: test pressure is 0.09 MPa, test temperature is 25°C, sample size is 4 cm in diameter, and effective area is 12.56 cm 2 , the testing time for all samples must be more than 5 minutes, and each group of samples must be tested at least 5 times.

[0125] The calculation formula of white oil flux parameters is: J = V / (A·t), where J is the white oil flux, L / (m 2 ·h); V is the volume of permeate, m 3 ; A is the effective area of ​​the sample, m 2 ; t is the effective time of the sample being tested, h.

[0126] The foamed polypropylene material-1 is prepared by foaming the injection-molded polypropylene material-1 with supercritical carbon dioxide; wherein the foamed polypropylene material-1 contains 90 wt % of random copolymerized polypropylene, has an average surface pore size of 50 μm, a bending strength of 0.15 MPa, and a thickness of 0.1 cm.

[0127] The foamed polypropylene material-2 is prepared by foaming the injection-molded polypropylene material-2 with supercritical carbon dioxide; wherein the foamed polypropylene material-2 has a random copolymer polypropylene content of 70 wt%, an average surface pore size of 40 μm, a bending strength of 0.45 MPa, and a thickness of 0.5 cm.

[0128] The foamed polypropylene material-3 is prepared by foaming the injection-molded polypropylene material-3 with supercritical carbon dioxide; wherein the foamed polypropylene material-3 contains 80 wt % of random copolymerized polypropylene, has an average surface pore size of 25 μm, a bending strength of 0.33 MPa, and a thickness of 1 cm.

[0129] Injection molding polypropylene material-1 (a blend of 70 wt% random copolymer polypropylene E02ES and 30 wt% POE) was purchased from Jiangsu Suzhou Shensai New Materials Co., Ltd., with a smooth surface, a bending strength of 10.5 MPa, and a thickness of 0.1 cm.

[0130] Injection molding polypropylene material-2 (a blend of 90 wt% random copolymer polypropylene E02ES and 10 wt% homopolymer polypropylene T30S) was purchased from Zhejiang Jiaxing Xinhengtai New Materials Co., Ltd. It has a smooth surface, a bending strength of 17.5 MPa, and a thickness of 0.1 cm.

[0131] Injection molding polypropylene material-3 (random copolymer polypropylene E02ES) was purchased from Ningbo Zhiwei New Material Technology Co., Ltd., with a smooth surface, a bending strength of 15.0 MPa, and a thickness of 0.1 cm.

[0132] Xylene (Sinopharm Chemical Reagent Co., Ltd.), decahydronaphthalene (Sinopharm Chemical Reagent Co., Ltd.), acetone (Xilong Science Co., Ltd.), sodium chloride (Sinopharm Chemical Reagent Co., Ltd.), vinyl silicone oil (Shandong Dayi Chemical Co., Ltd.), vinyl hydrogen silicone oil (Tokyo Chemical Industry Co., Ltd.), divinyl silicone oil (Shandong Dayi Chemical Co., Ltd.), sodium chloride (Sinopharm Chemical Reagent Co., Ltd.), graphene oxide (GO) aqueous solution (Nanjing Jicang Nanotechnology Co., Ltd.), ascorbic acid (J&K), styrene (Sinopharm Chemical Reagent Co., Ltd.); other raw materials were commercially available.

[0133] The physical properties of the cross-section / hydrophobic surface of the porous materials prepared in Example and Comparative Example 1, as well as the physical properties of the porous materials, are listed in Table 1.

[0134] Example 1

[0135] (1) 10 g of polypropylene material (foamed polypropylene material-1, water contact angle of 108°) was immersed in 500 g of etchant (xylene), and the mixture was sealed and immersed in a thermostat at 25°C for 12 h, and then placed in a 90°C forced air drying oven for 2 h to obtain a modified polypropylene material;

[0136] (2) dissolving 50 parts by weight of a monomer having an oleophilic side group (vinyl silicone oil) in 100 parts by weight of ethanol to obtain a monomer-containing solution; dissolving 20 parts by weight of an inorganic microwave absorbing medium (sodium chloride) in 100 parts by weight of deionized water to obtain a dispersion containing the inorganic microwave absorbing medium;

[0137] 100 parts by weight of the modified polypropylene material, the monomer-containing solution, and the inorganic microwave absorbing medium-containing dispersion are mixed, and the resulting mixture is dried in a forced air drying oven at 80° C.;

[0138] The dried mixture was irradiated with microwaves at an irradiation power of 2000 W for 25 seconds, and the cycle was repeated twice with an interval of 1 minute between each cycles. The microwave-irradiated product was then immersed in deionized water for 10 minutes, and the deionized water was replaced three times to ensure that the vinyl silicone oil and sodium chloride that did not participate in the grafting reaction were removed. The washed product was then placed in a forced air dryer at 80° C. to obtain a porous material P1. The porous material cross section S1 was obtained by freeze cutting.

[0139] (3) The porous material P1 is used as the oil-water separation material, and multiple oil-water separation materials are assembled to obtain an oil-water separation assembly, wherein the ratio of the distance between two adjacent oil-water separation materials to the thickness of the oil-water separation materials is 8:1.

[0140] Among them, the SEM image of the porous material cross section S1 is as follows Figure 1 As shown by Figure 1 It can be seen that the cross section S1 of the porous material has micro-nano structures and pores.

[0141] The distribution diagram of the lipophilic side group (Si element) of the porous material cross section S1 is as follows: Figure 2 As shown by Figure 2 It can be seen that the oleophilic side groups in the porous material cross section S1 can be evenly distributed on the micro-nanostructure.

[0142] Example 2

[0143] (1) 10 g of polypropylene material (foamed polypropylene material-1, water contact angle of 108°) was immersed in 1000 g of etchant (xylene), and the mixture was sealed and immersed in a thermostat at 25°C for 12 h, and then placed in a 90°C forced air drying oven for 2 h to obtain a modified polypropylene material;

[0144] (2) dissolving 60 parts by weight of a monomer having an oleophilic side group (vinyl silicone oil) in 100 parts by weight of ethanol to obtain a monomer-containing solution; dissolving 10 parts by weight of an inorganic microwave absorbing medium (sodium chloride) in 50 parts by weight of deionized water to obtain a dispersion containing the inorganic microwave absorbing medium;

[0145] 100 parts by weight of the modified polypropylene material, the monomer-containing solution, and the inorganic microwave absorbing medium-containing dispersion are mixed, and the resulting mixture is dried in a forced air drying oven at 80° C.;

[0146] The dried mixture was irradiated with microwaves at an irradiation power of 2000 W for 20 seconds, and the cycle was repeated three times with an interval of 1 minute between each cycles. The microwave-irradiated product was then immersed in deionized water for 10 minutes, and the deionized water was replaced three times to ensure that the vinyl silicone oil and sodium chloride that did not participate in the grafting reaction were removed. The washed product was then placed in a forced air dryer at 80° C. to obtain a porous material P2. The porous material cross section S2 was obtained by freeze cutting.

[0147] (3) The porous material P2 is used as the oil-water separation material, and multiple oil-water separation materials are assembled to obtain an oil-water separation component, wherein the ratio of the distance between two adjacent oil-water separation materials to the thickness of the oil-water separation material is 8:1.

[0148] Among them, the SEM image of the porous material cross section S2 is Figure 1 Similar; the distribution of lipophilic side groups (Si elements) in the porous material cross section S2 is similar to Figure 2 similar.

[0149] Example 3

[0150] (1) 10 g of polypropylene material (foamed polypropylene material-2, water contact angle of 112°) was immersed in 900 g of etchant (xylene), and immersed in a closed thermostat at 50°C for 4 h, and then placed in a 90°C forced air drying oven for 2 h to obtain a modified polypropylene material;

[0151] (2) dissolving 70 parts by weight of a monomer having an oleophilic side group (vinyl silicone oil) in 200 parts by weight of ethanol to obtain a monomer-containing solution; dissolving 20 parts by weight of an inorganic microwave absorbing medium (sodium chloride) in 100 parts by weight of deionized water to obtain a dispersion containing the inorganic microwave absorbing medium;

[0152] 100 parts by weight of the modified polypropylene material, the monomer-containing solution, and the inorganic microwave absorbing medium-containing dispersion are mixed, and the resulting mixture is dried in a forced air drying oven at 80° C.;

[0153] The dried mixture was microwave irradiated at an irradiation power of 10,000 W for 30 seconds, and the cycle was repeated three times with an interval of 1 minute between each cycles. The microwave irradiated product was then immersed in deionized water for 10 minutes, and the deionized water was replaced three times to ensure that the vinyl silicone oil and sodium chloride that did not participate in the grafting reaction were removed. The washed product was then placed in a forced air dryer at 80° C. to obtain a porous material P3. The porous material cross section S3 was obtained by freeze cutting.

[0154] (3) The porous material P3 is used as the oil-water separation material, and multiple oil-water separation materials are assembled to obtain an oil-water separation assembly, wherein the ratio of the distance between two adjacent oil-water separation materials to the thickness of the oil-water separation material is 8:1.

[0155] Among them, the SEM image of the porous material cross section S3 is Figure 1 Similar; the distribution of lipophilic side groups (Si elements) in the porous material cross section S3 is similar to Figure 2 similar.

[0156] Example 4

[0157] (1) 10 g of polypropylene material (foamed polypropylene material-3, water contact angle of 108°) was immersed in 500 g of etchant (xylene), and the mixture was sealed and immersed in a thermostat at 25°C for 10 h, and then placed in a forced air drying oven at 80°C for 2 h to obtain a modified polypropylene material;

[0158] (2) dissolving 50 parts by weight of a monomer having an oleophilic side group (vinyl silicone oil) in 200 parts by weight of ethanol to obtain a monomer-containing solution; dissolving 30 parts by weight of an inorganic microwave absorbing medium (graphene oxide) and 3 parts by weight of ascorbic acid (as a reducing agent for graphene oxide) in 150 parts by weight of deionized water to obtain a dispersion containing the inorganic microwave absorbing medium;

[0159] 100 parts by weight of the modified polypropylene material, the monomer-containing solution, and the inorganic microwave absorbing medium-containing dispersion are mixed, and the resulting mixture is dried in a forced air drying oven at 80° C.;

[0160] The dried mixture was irradiated with microwaves at an irradiation power of 15,000 W for 3 seconds, and the cycle was repeated 5 times with an interval of 1 minute between each cycles. The microwave-irradiated product was then immersed in deionized water for 10 minutes, and the deionized water was replaced 3 times to ensure that the vinyl silicone oil and sodium chloride that did not participate in the grafting reaction were removed. The washed product was then placed in a forced air dryer at 80° C. to obtain a porous material P4. The porous material cross section S4 was obtained by freeze cutting.

[0161] (3) The porous material P4 is used as the oil-water separation material, and multiple oil-water separation materials are assembled to obtain an oil-water separation assembly, wherein the ratio of the distance between two adjacent oil-water separation materials to the thickness of the oil-water separation materials is 8:1.

[0162] Among them, the SEM image of the porous material cross section S4 is Figure 1 Similar; the distribution of lipophilic side groups (Si elements) in the porous material cross section S4 is similar to Figure 2 similar.

[0163] Example 5

[0164] (1) 10 g of polypropylene material (foamed polypropylene material-3, water contact angle of 108°) was immersed in 900 g of etchant (xylene), and the mixture was sealed and immersed in a thermostat at 25°C for 10 h, and then placed in a forced air drying oven at 80°C for 2 h to obtain a modified polypropylene material;

[0165] (2) dissolving 65 parts by weight of a monomer having an oleophilic side group (vinyl silicone oil) in 200 parts by weight of ethanol to obtain a monomer-containing solution; dissolving 20 parts by weight of an inorganic microwave absorbing medium (graphene oxide) and 2.5 parts by weight of ascorbic acid (as a reducing agent for graphene oxide) in 150 parts by weight of deionized water to obtain a dispersion containing the inorganic microwave absorbing medium;

[0166] 100 parts by weight of the modified polypropylene material, the monomer-containing solution, and the inorganic microwave absorbing medium-containing dispersion are mixed, and the resulting mixture is dried in a forced air drying oven at 80° C.;

[0167] The dried mixture was irradiated with microwaves at an irradiation power of 20,000 W for 2 seconds, and the cycle was repeated four times with an interval of 1 minute between each cycles. The microwave-irradiated product was then immersed in deionized water for 10 minutes, and the deionized water was replaced three times to ensure that the vinyl silicone oil and sodium chloride that did not participate in the grafting reaction were removed. The washed product was then placed in a forced air dryer at 80° C. to obtain a porous material P5. A cross-section S5 of the porous material was obtained by freeze-cutting.

[0168] (3) The porous material P5 is used as the oil-water separation material, and multiple oil-water separation materials are assembled to obtain an oil-water separation assembly, wherein the ratio of the distance between two adjacent oil-water separation materials to the thickness of the oil-water separation materials is 8:1.

[0169] Among them, the SEM image of the porous material cross section S5 is Figure 1 Similar; the distribution of lipophilic side groups (Si elements) in the porous material cross section S5 is similar to Figure 2 similar.

[0170] Example 6

[0171] The method of Example 1 is followed, except that 10 g of polypropylene material (foamed polypropylene material-1, with a water contact angle of 108°) is replaced with 35 g of polypropylene material (foamed polypropylene material-1, with a water contact angle of 108°), and the other conditions are the same, to obtain porous material P6 and porous material cross-section S6.

[0172] Example 7

[0173] The method of Example 1 is followed, except that 50 parts by weight of the monomer having lipophilic side groups (vinyl silicone oil) are replaced by 40 parts by weight of the monomer having lipophilic side groups (vinyl silicone oil), and the other conditions are the same, to obtain porous material P7 and porous material cross-section S7.

[0174] Example 8

[0175] The method of Example 1 is followed, except that in step (2), 20 parts by weight of the inorganic microwave absorbing medium (sodium chloride) is replaced by 10 parts by weight of the inorganic microwave absorbing medium (sodium chloride), and the other conditions are the same, to obtain porous material P8 and porous material cross section S8.

[0176] Example 9

[0177] The method of Example 1 is followed, except that in step (2), 100 parts by weight of modified polypropylene material, 50 parts by weight of a monomer having an oleophilic side group (vinyl silicone oil), and 20 parts by weight of an inorganic microwave absorbing medium (sodium chloride) are directly mixed, and the other conditions are the same to obtain porous material P9 and porous material cross section S9.

[0178] Comparative Example 1

[0179] The method of Example 1 is followed, except that step (2) is omitted, that is, the modified polypropylene material obtained in step (1) is used as the porous material DP1, and the other conditions are the same to obtain the porous material cross section DS1.

[0180] Comparative Example 1'

[0181] The method of Example 1 was followed, except that the foamed polypropylene material-1 was replaced by the injection-molded polypropylene material-1, and other conditions were the same, to obtain a hydrophobic surface D1'.

[0182] Comparative Example 2

[0183] The method of Example 3 is followed, except that step (2) is omitted, that is, the modified polypropylene material obtained in step (1) is used as the porous material DP2, and the other conditions are the same to obtain the porous material cross section DS2.

[0184] Comparative Example 2'

[0185] The method of Example 3 was followed, except that the foamed polypropylene material-2 was replaced by the injection-molded polypropylene material-2, and the other conditions were the same, to obtain a hydrophobic surface D2'.

[0186] Comparative Example 3

[0187] The method of Example 4 is followed, except that step (2) is omitted, that is, the modified polypropylene material obtained in step (1) is used as the porous material DP3, and the other conditions are the same to obtain the porous material cross section DS3.

[0188] Comparative Example 3'

[0189] The method of Example 4 was followed, except that the foamed polypropylene material-3 was replaced by the injection-molded polypropylene material-3. Other conditions were the same, to obtain a hydrophobic surface D3'.

[0190] Comparative Example 4

[0191] The method of Example 1 is followed, except that step (1) is omitted, that is, 100 parts by weight of the polypropylene material, the above-mentioned monomer-containing solution, and the above-mentioned dispersion containing the inorganic microwave absorbing medium are mixed, and other conditions are the same to obtain the porous material DP4 and the porous material cross-section DS4.

[0192] Comparative Example 5

[0193] The method of Example 1 is followed, except that in step (2), no inorganic microwave absorbing medium is added. That is, 100 parts by weight of the modified polypropylene material and the above-mentioned monomer-containing solution are mixed, and the other conditions are the same to obtain the porous material DP5 and the porous material cross section DS5.

[0194] Table 1

[0195]

[0196] As can be seen from the data in Table 1, compared with the polypropylene material, the porous material cross-section provided by the present invention significantly improves the hydrophobicity and oleophilicity of the porous material cross-section while ensuring unchanged mechanical properties. That is, the porous material cross-section has a larger water contact angle and a smaller white oil contact angle. In particular, by adjusting the surface grafting rate parameters of the porous material cross-section, the porous material has a larger porosity and an average pore diameter, thereby effectively improving the oil-water separation efficiency of the oil-water separation component containing the porous material, that is, the porous material has a larger white oil flux and water retention rate.

[0197] Compared with Example 6, Example 1 further improves the porosity, average pore diameter, white oil flux and water retention rate of the porous material by limiting the weight ratio of the polypropylene material to the etchant within the preferred protection range, increasing the water contact angle and grafting rate of the cross section of the porous material, and reducing the white oil contact angle of the porous material.

[0198] Compared with Example 7, Example 1 further improves the porosity, average pore diameter, white oil flux and water retention rate of the porous material by limiting the weight ratio of the monomer and the modified polypropylene material within the preferred protection range, increasing the water contact angle and grafting rate of the cross section of the porous material, and reducing the white oil contact angle of the porous material.

[0199] Compared with Example 8, Example 1 further improves the porosity, average pore diameter, white oil flux and water retention rate of the porous material by limiting the weight ratio of the inorganic microwave absorbing medium and the modified polypropylene material within the preferred protection range, increasing the water contact angle and grafting rate of the cross section of the porous material, and reducing the white oil contact angle of the porous material.

[0200] Compared with Example 9, Example 1 further improves the porosity, average pore diameter, white oil flux and water retention rate of the porous material by limiting the mixing of monomers in the form of a solution and the mixing of the inorganic microwave absorbing medium in the form of a dispersion, increasing the water contact angle and grafting rate of the cross section of the porous material, and reducing the white oil contact angle of the porous material.

[0201] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. An oil-water separation component, characterized in that: The oil-water separation component is assembled from a plurality of oil-water separation materials, and the ratio of the distance between two adjacent oil-water separation materials to the thickness of the oil-water separation materials is 1-10:1; The oil-water separation material is a porous material, and the porous material is a polypropylene material having a plurality of micro-nano structures on the surface and inside, and the micro-nano structures are grafted with oleophilic side groups; Wherein, on the cross section of the porous material, the surface grafting rate of the oleophilic side groups is 20-60 wt%; The oil-water separation material is prepared by the following method: contacting a polypropylene material with an etchant and performing a first drying to form a plurality of micro-nano structures on the surface and inside the polypropylene material to obtain a modified polypropylene material; mixing the modified polypropylene material, a monomer having oleophilic side groups, and an inorganic microwave absorbing medium, and subjecting the resulting mixture to microwave irradiation to graft oleophilic side groups onto the micro-nano structures of the modified polypropylene material, and using the resulting porous material as the oil-water separation material; the contact conditions include: a temperature of 15-70°C and a time of 1-24 hours; and the microwave irradiation conditions include: an irradiation power of 1500-27000W and an irradiation time of 1 second to 1 minute. Wherein, the polypropylene material is a foamed polypropylene material, the surface average pore diameter of the foamed polypropylene material is 10-100 μm, the bending strength is 0.1-1 MPa, and the thickness is 0.1-1 cm.

2. The oil-water separation assembly according to claim 1, wherein: The oil-water separation component is composed of a plurality of the oil-water separation materials assembled in parallel; And / or, in the oil-water separation component, the number of the oil-water separation materials is ≥2; And / or, the ratio of the distance between two adjacent oil-water separation materials to the thickness of the oil-water separation material is 2-8:

1.

3. The oil-water separation assembly according to claim 1, wherein: In the oil-water separation component, the number of the oil-water separation materials is 2-3.

4. The oil-water separation assembly according to claim 1, wherein: The porosity of the porous material is 60-95%; And / or, the porous material has pores that run through from top to bottom, and the average diameter of the pores is 10-100 μm; And / or, the water contact angle of the porous material cross section is ≥150°; the white oil contact angle is ≤30°; And / or, the water retention rate of the porous material is 80-100%; the white oil flux is 250-1000 L / m 2 ·h.

5. The oil-water separation assembly according to claim 4, wherein: The porosity of the porous material is 75-90%; And / or, the porous material has pores that run through from top to bottom, and the average diameter of the pores is 20-60 μm; And / or, the water contact angle of the porous material cross section is 150-180°; the white oil contact angle is 0-10°; And / or, the water retention rate of the porous material is 90-100%; the white oil flux is 300-500L / m 2 ·h.

6. The oil-water separation assembly according to claim 1, wherein: The average pore size of the surface of the foamed polypropylene material is 20-60 μm; Bending strength is 0.1-0.5MPa; Thickness is 0.1-0.5cm; And / or, the foamed polypropylene material is prepared by foaming at least one selected from a homopolymer polypropylene material having a polypropylene content of ≥50wt%, a random copolymer polypropylene material, and an impact copolymer polypropylene material; And / or, each of the micro-nano structures has a length of 1 nm to 100 μm and a depth of 1 μm to 1 mm; And / or, the oleophilic side groups are selected from vinyl silicone oil side groups and / or styrene side groups.

7. The oil-water separation assembly according to claim 6, wherein: The length of each micro-nano structure is 500 nm-50 μm, and the depth is 50-500 μm.

8. A method for preparing an oil-water separation component, characterized in that: The method comprises the following steps: (1) contacting a polypropylene material with an etchant and performing a first drying process to form a plurality of micro-nano structures on the surface and inside of the polypropylene material to obtain a modified polypropylene material; (2) mixing the modified polypropylene material, a monomer having oleophilic side groups, and an inorganic microwave absorbing medium, and subjecting the resulting mixture to microwave irradiation to graft oleophilic side groups onto the micro-nanostructure of the modified polypropylene material, and using the resulting porous material as an oil-water separation material; (3) assembling a plurality of the oil-water separation materials to obtain an oil-water separation assembly; Wherein, the ratio of the distance between two adjacent oil-water separation materials to the thickness of the oil-water separation material is 1-10:1; Wherein, on the cross section of the porous material, the surface grafting rate of the oleophilic side groups is 20-60 wt%; The contact conditions include: a temperature of 15-70° C. and a time of 1-24 hours; the microwave irradiation conditions include: an irradiation power of 1500-27000 W and an irradiation time of 1 second to 1 minute; Wherein, the polypropylene material is a foamed polypropylene material, the surface average pore diameter of the foamed polypropylene material is 10-100 μm, the bending strength is 0.1-1 MPa, and the thickness is 0.1-1 cm.

9. The method according to claim 8, wherein In step (1), the weight ratio of the polypropylene material to the etchant is 0.01-10:100; And / or, the etchant is a polar organic solvent; And / or, the contact conditions include: temperature of 20-60°C; time of 5-15h; And / or, the first drying conditions include: temperature of 80-120° C.; time of 1-10 h.

10. The method according to claim 9, wherein: In step (1), the weight ratio of the polypropylene material to the etchant is 0.01-5:100; and / or, the etchant is selected from at least one of toluene, xylene, diphenyl ether, butyl acetate, isoamyl acetate, n-heptane, n-octane and decahydronaphthalene; And / or, the first drying conditions include: a temperature of 80-100°C; The time is 1-5 hours.

11. The method according to claim 8, wherein In step (2), the weight ratio of the monomer to the modified polypropylene material is 40-70:100; And / or, the monomer is selected from vinyl-terminated silicone oil and / or high vinyl silicone oil; And / or, in step (2), the weight ratio of the inorganic microwave absorbing medium to the modified polypropylene material is 10-50:

100.

12. The method according to claim 11, wherein In step (2), the weight ratio of the monomer to the modified polypropylene material is 50-70:100; And / or, the monomer is selected from at least one of vinyl silicone oil, vinyl hydrogen silicone oil and divinyl silicone oil; And / or, in step (2), the weight ratio of the inorganic microwave absorbing medium to the modified polypropylene material is 20-30:

100.

13. The method according to claim 12, wherein: The monomer is selected from methyl vinyl silicone oil.

14. The method according to claim 8, wherein In step (2), the microwave irradiation conditions include: irradiation power of 1500-15000W; irradiation time of 1-30s.

15. The method according to claim 14, wherein In step (3), the assembling method includes: assembling a plurality of the porous materials in parallel to obtain an oil-water separation component; and / or, before the microwave irradiation, subjecting the mixture to a second drying; The method further comprises: washing the microwave irradiated product, or washing the microwave irradiated product after reacting with a base.

16. The method according to claim 15, wherein The method further includes: performing a third drying on the washed product.

17. An oil-water separator, characterized in that: The oil-water separator comprises: a feed inlet, an oil outlet, at least one water outlet, and at least one oil-water separation component; Wherein, the oil-water separation component is the oil-water separation component described in any one of claims 1-7, or the oil-water separation component produced by the method described in any one of claims 8-16.

18. The oil-water separator according to claim 17, wherein: Two adjacent oil-water separation components are arranged in parallel inside the oil-water separator at a distance of 10-30 cm; And / or, the number of the water outlets and the number of the oil-water separation components are the same, and are independently ≥2; And / or, the water outlet is arranged on the upper part of the oil-water separation component, and the height difference between the water outlet and the oil-water separation component is ≤0.5 cm.

19. The oil-water separator according to claim 18, wherein: The number of the water outlets and the oil-water separation components is the same, and each is independently 2-3; And / or, the water outlet is arranged on the upper part of the oil-water separation component, and the height difference between the water outlet and the oil-water separation component is 0-0.5 cm.

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