Grafted modified omentum, preparation method, application, and sewage treatment device and method

Abstract

The present invention relates to the field of water treatment, and more particularly to a grafted modified omentum, a preparation method, and its application, as well as a sewage treatment device and method. The grafted modified omentum has high separation efficiency, minimal impact on the mechanical properties of the material, and low preparation cost. When used for oil-water separation, the material is safe to operate, has low energy consumption, low operating costs, and can achieve stable water removal indicators even in long-term operation without causing secondary pollution.

Description

Technical Field

[0001] The invention relates to the field of water treatment, and in particular to a grafted modified omentum, a preparation method and application thereof, and a treatment device and method for sewage. Background Art

[0002] Crude oil and other mineral oils primarily consist of alkanes, aromatic hydrocarbons, asphaltenes, and resins. These are highly complex and toxic hydrocarbons. Once they enter water bodies, they severely deteriorate water quality and indirectly harm the soil, atmosphere, biodiversity, and urban landscape. As the processing scale of oil refining companies expands and crude oil properties become increasingly sulfurized, heavier, and inferior, the quality of wastewater generated by production facilities is becoming increasingly complex. Electrodesalting and other industrial oily wastewater generates large volumes and is complex in composition. In addition to oil, it also contains impurities such as solid particles, salts, and various organic compounds. Furthermore, its chemical oxygen demand (COD) is high. Direct discharge without treatment can severely pollute the environment, making the treatment of oily wastewater more difficult and making it difficult for discharged wastewater to meet discharge standards.

[0003] Membrane separation technology treats oily wastewater based on the membrane's microporous screening effect and unique wetting properties. This method offers advantages such as simplicity, high efficiency, flexible and easy operation, minimal environmental pollution, and strong versatility, making it an important future development direction for oil-water separation membranes. However, traditional two-dimensional porous polymer separation membranes experience a trade-off between flux and selectivity when treating oily wastewater, especially when separating oil-water emulsions. They struggle to achieve both high permeability and high selectivity, suffer from rapid flux decay, low separation efficiency, require external driving pressure, are prone to fouling, and are limited in the types of oily wastewater they can treat.

[0004] In order to overcome the shortcomings of traditional two-dimensional structural polymer membranes, some researchers have used silk screen, organic microfiltration membranes, etc. as substrates, and dipped and coated them with super-hydrophilic materials to construct micro-nano structures to form mesh membranes. This can effectively overcome the weaknesses of two-dimensional symmetrical membranes such as poor pressure resistance, rapid flux attenuation, and low separation efficiency. However, in actual use, the preparation method of this type of mesh membrane is complicated, the service life is short, and the resistance to expansion and chemicals is poor. It cannot adapt to the separation of oil-water mixtures in complex chemical environments, and it is difficult to achieve large-scale industrial applications.

[0005] Therefore, it is necessary to prepare an oil-water separation modified material with high separation efficiency, little effect on the mechanical properties of the main material, simple preparation process and low preparation cost. When using this material for oil-water separation, it can achieve high throughput, safe operation, low operating cost, no secondary pollution, and long-term operation can also make the water removal indicators stably meet the standards. Summary of the Invention

[0006] The purpose of the present invention is to overcome the above-mentioned problems existing in the prior art and to provide a grafted modified omentum and its preparation method and application as well as a treatment device and treatment method containing sewage. The omentum has a three-dimensional network structure. When used for oil-water separation, a higher oil removal rate can be obtained, and the operation is simple and safe. Long-term operation can also ensure that the water removal index meets the standard stably.

[0007] In order to achieve the above-mentioned object, the first aspect of the present invention provides a graft modified omentum, wherein the graft modified omentum has a three-dimensional network structure, and the omentum contains structural units derived from polypropylene and structural units derived from vinyl functional monomers;

[0008] The weight of the grafted modified omentum is greater than 80 g / m 2 , thickness greater than 15 mm, and porosity greater than 17 volume %.

[0009] A second aspect of the present invention provides a method for preparing a grafted modified omentum, the method comprising:

[0010] (1) melting polypropylene and an optional antioxidant to obtain a spinning solution, and spinning the spinning solution to obtain polypropylene fibers;

[0011] (2) using vinyl functional monomers to modify polypropylene fibers by microwave irradiation to obtain modified polypropylene fibers;

[0012] (3) forming a network of modified polypropylene fibers to obtain a grafted modified network membrane having a three-dimensional network structure;

[0013] The conditions of the web forming treatment make the weight of the grafted modified web greater than 80 g / m 2 , thickness greater than 15mm, porosity greater than 17% by volume

[0014] The third aspect of the present invention provides a grafted modified omentum prepared by the method described above.

[0015] The fourth aspect of the present invention provides the use of the grafted modified omentum provided in the first aspect or the third aspect of the present invention in treating oily wastewater.

[0016] A fifth aspect of the present invention provides a device for treating oily wastewater, which comprises, in order according to the direction of the material, a liquid storage tank and an oil-water separator;

[0017] Wherein, the liquid storage tank is used to store oily wastewater; the oil-water separator is filled with the grafted modified mesh membrane provided by the first aspect or the third aspect of the present invention, for oil-water separation;

[0018] The oil-water separator is further connected to a water production tank and an oil collecting tank respectively. The water production tank is used to receive the water phase from the oil-water separator, and the oil collecting tank is used to receive the oil phase from the oil-water separator.

[0019] A sixth aspect of the present invention provides a method for treating oily wastewater, which is carried out in the apparatus described above. The method comprises: introducing the oily wastewater in the liquid storage tank into an oil-water separator for oil-water separation.

[0020] Through the above technical solution, the present invention can achieve the following beneficial effects:

[0021] 1. The grafted modified membrane provided by the present invention has a three-dimensional network structure, which increases the critical penetration pressure of oil. When oily wastewater passes through the membrane, water can pass through it first and smoothly with a higher separation flux, while the oil is retained, that is, it can intercept oil and guide water, realize oil-water separation, and has the characteristics of high oil removal rate.

[0022] 2. The grafted modified omentum provided by the present invention has a stable and long-lasting modification effect and does not affect the mechanical properties of the material itself. Long-term operation can also ensure that the water removal index meets the standard stably, that is, it is effective in the long term.

[0023] 3. The oily wastewater treatment device provided by the present invention has a compact structure, small size, and is fully enclosed. When it is used for the treatment of oily wastewater, the treatment process is safe and explosion-proof, with a small pressure drop, simple operation, low operating cost, no waste residue generated, no secondary pollution caused, stable effect, and long-term operation can ensure that the effluent indicators are stable and meet the standards. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The invention provides a device for treating oily wastewater.

[0025] Description of Reference Numerals

[0026] 1-Liquid storage tank; 2-Sewage pump; 3-Sewage tank; 4-Flow regulating valve; 5-Flow meter; 6-Feed pump; 7-Oil-water separator; 8-Production water tank; 9-Oil collecting tank. DETAILED DESCRIPTION

[0027] 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.

[0028] In the present invention, the "porosity" mentioned refers to the percentage of the volume of pores in the material to the total volume of the material.

[0029] In a first aspect, the present invention provides a grafted modified omentum, wherein the grafted modified omentum has a three-dimensional network structure, and the omentum contains structural units derived from polypropylene and structural units derived from vinyl functional monomers;

[0030] The weight of the grafted modified omentum is greater than 80 g / m 2 , thickness greater than 15 mm, and porosity greater than 17 volume %.

[0031] Among them, the vinyl functional monomer can modify the oil-water wetting properties of the polypropylene material surface, so that the grafted modified membrane has strong hydrophilicity. When the membrane is used for oil-water separation, after the oily wastewater comes into contact with the membrane, water quickly spreads on the membrane surface or in the pores to form a hydration layer. The hydration layer has great adhesion on the membrane surface, thereby preventing the oil droplets from contacting the membrane surface. At the same time, since the density of water is generally greater than that of oil, the water is in the lower layer. Due to the incompatibility between water and oil and the huge surface tension, the oil cannot curl into a sphere and form a sheet on the water surface. As the oil increases, an oil phase is formed, so that the oil and water are separated.

[0032] According to the present invention, in order to further improve the oil removal rate of the omentum, preferably, the weight of the grafted modified omentum is 100-700 g / m 2 (For example, it can be 100g / m 2 , 200g / m 2 , 300g / m 2 , 400g / m 2 , 500g / m 2 , 600g / m 2 , 700g / m 2 and the values within the range formed by any two of the above values), the thickness is 20-80 mm (for example, it can be 20 mm, 30 mm, 40 mm, 50 mm, 60 mm, 70 mm, 80 mm and the values within the range formed by any two of the above values), the porosity is 20-85 volume % (for example, it can be 20 volume %, 30 volume %, 40 volume %, 50 volume %, 60 volume %, 70 volume %, 80 volume %, 85 volume %); more preferably, the gram weight of the grafted modified omentum is 200-500 g / m 2 , thickness of 30-60 mm, porosity of 55-80% by volume. The inventors of the present invention have found in their research that when the gram weight, thickness and porosity of the omentum are within the above ranges, the pore distribution of the omentum is reasonable, which can increase the critical penetration pressure of the oil, and further maintain a large flux while ensuring a high oil removal rate, meeting the scale requirements of industrial applications.

[0033] According to the present invention, in order to further improve the oil removal rate of the omentum, preferably, according to the ASTM D1238-13 method, the melt index of the polypropylene at a temperature of 230°C and a load weight of 2.16 kg is 100-1000 g / 10 min. The inventors of the present invention found in their research that the polypropylene in this melt index range has better fluidity, processability and mechanical properties of the prepared omentum, which is more conducive to improving the oil removal rate of the omentum.

[0034] According to the present invention, in order to further improve the oil removal rate of the omentum and further ensure long-term effectiveness, preferably, the vinyl functional monomer is selected from at least one of acrylamide, propylene sulfonic acid, p-vinylbenzenesulfonic acid, acrylic acid, methacrylic acid, hydroxyethyl methacrylate and N-vinyl pyrrolidone.

[0035] According to the present invention, in order to further ensure long-term effectiveness, preferably, the grafted modified omentum further includes an antioxidant.

[0036] According to the present invention, in order to further ensure long-term effectiveness, preferably, the antioxidant is selected from at least one of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]pentaerythritol ester (which may be commercially available antioxidant 1010), tris(2,4-di-tert-butyl)phenyl phosphite (which may be commercially available antioxidant 168), β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (which may be commercially available antioxidant 1076), 2,6-di-tert-butyl-4-methylphenol (which may be commercially available antioxidant 264), N,N'-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine (which may be commercially available antioxidant 1024) and triphenyl phosphite (which may be commercially available antioxidant TPP).

[0037] According to the present invention, preferably, the content ratio of the structural unit derived from polypropylene to the antioxidant is 100:1-5.5 by weight.

[0038] In a second aspect, the present invention provides a method for preparing a grafted modified omentum, the method comprising:

[0039] (1) melting polypropylene and an optional antioxidant to obtain a spinning solution, and spinning the spinning solution to obtain polypropylene fibers;

[0040] (2) using vinyl functional monomers to modify polypropylene fibers by microwave irradiation to obtain modified polypropylene fibers;

[0041] (3) forming a network of modified polypropylene fibers to obtain a grafted modified network membrane having a three-dimensional network structure;

[0042] The conditions of the web forming treatment make the weight of the grafted modified web greater than 80 g / m2 , thickness greater than 15 mm, and porosity greater than 17 volume %.

[0043] It is understood that whether to add an antioxidant during the preparation process can be selected according to the needs of the product to be prepared.

[0044] According to the present invention, in order to further improve the oil removal rate of the prepared omentum, preferably, in step (1), according to the ASTM D1238-13 method, the melt index of the polypropylene at a temperature of 230° C. and a load weight of 2.16 kg is 100-1000 g / 10 min.

[0045] According to the present invention, in order to further ensure long-term effectiveness, preferably, the antioxidant is selected from at least one of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]pentaerythritol ester (which may be commercially available antioxidant 1010), tris(2,4-di-tert-butyl)phenyl phosphite (which may be commercially available antioxidant 168), β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (which may be commercially available antioxidant 1076), 2,6-di-tert-butyl-4-methylphenol (which may be commercially available antioxidant 264), N,N'-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine (which may be commercially available antioxidant 1024) and triphenyl phosphite (which may be commercially available antioxidant TPP).

[0046] According to the present invention, the weight ratio of the polypropylene to the antioxidant is 100:1-5.5.

[0047] According to the present invention, preferably, the melting temperature is 175-200° C. (for example, 175° C., 180° C., 190° C., 200° C.) The melting time is not particularly limited, as long as the polypropylene and the optional antioxidant can be melted as much as possible.

[0048] According to the present invention, in order to make the spinning solution more uniform and to make the prepared omentum have a higher oil removal rate, preferably, the method further comprises: stirring and degassing after melting;

[0049] According to the present invention, preferably, the stirring conditions include: stirring in a nitrogen atmosphere for 1-4 hours.

[0050] According to the present invention, preferably, the degassing conditions include: standing for 0.5-2 hours.

[0051] According to the present invention, preferably, before spinning, the spinning solution is subjected to solid-liquid separation to remove the unmelted solid phase therein. The method of the solid-liquid separation is not particularly limited, and is preferably filtration.

[0052] According to the present invention, preferably, the spinning method further comprises: sequentially extruding, spinning, stretching and cooling the spinning solution.

[0053] According to the present invention, in order to further improve the oil removal rate of the prepared omentum, preferably, the spinning conditions make the diameter of the polypropylene fiber 10-60μm (for example, it can be 10μm, 20μm, 30μm, 40μm, 50μm, 60μm).

[0054] According to the present invention, preferably, the extrusion conditions include: an extrusion temperature of 140-175°C. The extrusion device is not particularly limited, and the material can be fed into a screw extruder through a pipeline. For example, when a pipeline is used to feed the screw extruder, the pipeline temperature, i.e., the extrusion temperature, is 140-175°C.

[0055] According to the present invention, preferably, the spinning conditions include: a spinneret aperture of 0.1-2 mm, and a temperature of 100-150°C.

[0056] According to the present invention, preferably, the stretching conditions include: using airflow stretching, the airflow temperature is 120-150°C, and the stretching spinning speed is 100-400 m / min. It can be understood that the spinning speed refers to the speed at which the fiber is formed during the airflow stretching process.

[0057] According to the present invention, preferably, the cooling condition includes: using air cooling, and the air temperature is 5-20°C.

[0058] According to the present invention, to further enhance the modification effect and achieve a higher oil removal rate for the prepared omentum, the method preferably further comprises, before modification, washing and drying the polypropylene fibers. It is understood that the washing is to remove impurities adhering to the polypropylene fibers, and the drying is to remove moisture adsorbed by the washed polypropylene fibers. The washing method may include soaking in ethanol for at least 12 hours, followed by washing with deionized water at least three times. The drying conditions may include a temperature of 65-75°C for 24-48 hours. The specific drying method is not particularly limited, but oven drying is preferred.

[0059] According to the present invention, preferably, the modification method comprises: immersing the polypropylene fiber in a vinyl functional monomer solution, taking it out, and subjecting it to microwave irradiation.

[0060] The solvent of the vinyl functional monomer solution is not particularly limited and can be any conventional solvent in the art, preferably ethanol, ethyl acetate or acetone. The concentration of the vinyl functional monomer in the vinyl functional monomer solution can be 1-15 mol / L.

[0061] According to the present invention, in order to further improve the oil removal rate of the prepared omentum and further ensure long-term effectiveness, preferably, the vinyl functional monomer is selected from at least one of acrylamide, propylene sulfonic acid, p-vinylbenzenesulfonic acid, acrylic acid, methacrylic acid, hydroxyethyl methacrylate and N-vinyl pyrrolidone.

[0062] According to the present invention, in order to further improve the oil removal rate of the prepared omentum and further ensure long-term effectiveness, preferably, the amount of the vinyl functional monomer is 1-15 mol relative to 1 kg of polypropylene fiber;

[0063] According to the present invention, preferably, the polypropylene fiber is immersed in a vinyl functional monomer solution, soaked, and shaken to allow more vinyl functional monomer to adhere to the polypropylene fiber, then removed, dried, and then placed in a microwave reactor for microwave irradiation modification. The soaking time is not particularly limited, as long as more vinyl functional monomer can be adhered to the polypropylene fiber, for example, it can be 2-4 hours. The soaking temperature, that is, the temperature of the vinyl functional monomer solution, can be room temperature.

[0064] According to the present invention, in order to further improve the oil removal rate of the prepared omentum and further ensure long-term effectiveness, preferably, in step (2), the microwave irradiation conditions include: a microwave frequency of 2000-3000 MHz (for example, it can be 2000 MHz, 2100 MHz, 2200 MHz, 2300 MHz, 2400 MHz, 2500 MHz, 2600 MHz, 2700 MHz, 2800 MHz, 2900 MHz, 3000 MHz and a value within a numerical range formed by any two of the above values). The microwave irradiation power is 100-2000w (for example, it can be 100w, 200w, 500w, 800w, 1000w, 1200w, 1500w, 1800w, 2000w and a numerical value within the numerical range formed by any two of the above values), and the time is 1-120min (for example, it can be 1min, 5min, 10min, 20min, 40min, 50min, 60min, 80min, 100min, 120min and a numerical value within the numerical range formed by any two of the above values).

[0065] It is understood that under microwave irradiation, the vinyl-functional monomer absorbs energy and generates free radicals, which also trigger the polypropylene chain to generate free radicals, resulting in a grafting reaction between the vinyl-functional monomer and the polypropylene. The microwave irradiation technique described above avoids the use of initiators, thereby avoiding the β-chain scission reaction of the polypropylene that is easily caused by the use of initiators. Furthermore, the inventors of the present invention have discovered that the microwave irradiation technique described above makes it easier to control and modify the surface of the material, and can also improve the oil removal rate of the resulting graft-modified mesh without changing the mechanical properties of the polypropylene itself.

[0066] According to the present invention, preferably, before the web forming process, the method further comprises: washing and drying the modified polypropylene fiber in sequence. The washing process may be performed at least three times with deionized water. The drying process may be performed by oven drying at 65-75°C.

[0067] According to the present invention, preferably, the web forming method comprises: carding, needling, and heat-sealing in sequence. It is understood that the carding is to use a carding machine to comb the fibers so that they are arranged neatly into a shape; the needling is to use a needle loom to needle the formed fibers so that the fibers are intertwined and connected to form a web; and the heat-sealing is to use a hot melt adhesive to further fix the fibers into a web film.

[0068] According to the present invention, in order to further improve the oil removal rate of the prepared omentum, preferably, the conditions of the web forming process make the weight of the grafted modified omentum be 100-700 g / m 2 , thickness is 20-80mm, porosity is 20-85% by volume; more preferably, the conditions of the web forming process make the weight of the grafted modified web be 200-500g / m 2 , thickness is 30-60mm, porosity is 55-80% by volume.

[0069] In a third aspect, the present invention provides a grafted modified omentum prepared by the method described above.

[0070] In a fourth aspect, the present invention provides the use of the grafted modified omentum provided in the first or third aspect of the present invention in treating oily wastewater.

[0071] In a fifth aspect, the present invention provides a treatment device for oily wastewater, which comprises, in order according to the direction of the material, a liquid storage tank and an oil-water separator;

[0072] Wherein, the liquid storage tank is used to store oily wastewater; the oil-water separator is filled with the grafted modified mesh membrane provided by the first aspect or the third aspect of the present invention for oil-water separation;

[0073] The oil-water separator is further connected to a water production tank and an oil collecting tank respectively. The water production tank is used to receive the water phase from the oil-water separator, and the oil collecting tank is used to receive the oil phase from the oil-water separator.

[0074] According to the present invention, preferably, the oily wastewater treatment device further includes a sewage tank located between the liquid storage tank and the oil-water separator, the sewage tank being configured to receive the oily wastewater from the liquid storage tank and transport it to the oil-water separator. The sewage tank is provided with a sewage tank inlet and a sewage tank outlet; the sewage tank inlet is connected to the liquid storage tank via a pipeline, and the sewage tank outlet is connected to the oil-water separator via a pipeline.

[0075] According to the present invention, preferably, the oily wastewater treatment device further comprises a sewage pump located on a pipeline between the liquid storage tank and the sewage tank, for pumping the sewage in the liquid storage tank into the sewage tank.

[0076] According to the present invention, preferably, according to the flow of materials, the oily wastewater treatment device further includes a flow regulating valve, a flow meter and a feed pump sequentially arranged on the pipeline between the wastewater tank and the oil-water separator.

[0077] According to the present invention, the oil-water separator is preferably provided with a sewage inlet, a water phase outlet, and an oil phase outlet. The sewage inlet is located at the upper portion of the oil-water separator. The sewage inlet is used to introduce oily sewage from the liquid storage tank into the oil-water separator, the water phase outlet is used to draw the water phase obtained after separation by the grafted modified membrane out of the oil-water separator and into the water production tank, and the oil phase outlet is used to draw the oil phase obtained after separation by the grafted modified membrane out of the oil-water separator and into the oil collection tank.

[0078] It is understood that when oily wastewater is separated through the oil-water separator, the grafted modified membrane therein has hydrophilic and oleophobic properties. Under the selective interception effect, the aqueous phase will pass through the grafted modified membrane and enter the lower portion of the oil-water separator, while the oil phase will be intercepted and remain in the upper portion of the oil-water separator. Preferably, the oil phase outlet is located at the top of the oil-water separator, and the water phase outlet is located at the lower portion of the oil-water separator.

[0079] According to the present invention, preferably, the water production tank is communicated with the water phase outlet of the oil-water separator through a pipeline, and the oil collecting tank is communicated with the oil phase outlet of the oil-water separator through a pipeline.

[0080] In a sixth aspect, the present invention provides a method for treating oily wastewater, which is carried out in the apparatus described above. The method comprises: introducing the oily wastewater in the liquid storage tank into an oil-water separator for oil-water separation.

[0081] According to the present invention, preferably, in the oil-water separator, the ratio of the filling volume of the grafted modified omentum to the volume of the oil-water separator is 1:2-4.

[0082] According to the present invention, preferably, in the oil-water separator, relative to the graft modified membrane with a filling volume of 300L, the oily wastewater feed rate is 0.1-0.5m 3 / h.

[0083] According to the present invention, preferably, the temperature of the oily wastewater is 40-60°C.

[0084] The packing volume may be the volume of the omentum packed under conventional packing operations in the art, for example, the volume of the omentum packed into the bed of the oil-water separator by layered compaction at 0.2 MPa.

[0085] According to a particularly preferred embodiment of the present invention, the preparation of the grafted modified omentum and the treatment of the oily wastewater are carried out according to the following method:

[0086] (1) Polypropylene with a melt index of 450-550 g / 10 min and antioxidant 1024 are mixed, wherein the amounts of the polypropylene and antioxidant are such that, by weight, the content ratio of the structural unit from the polypropylene to the antioxidant in the grafted modified mesh is 28-35:1; and the crystal form is melted at 182-187° C.; and then stirred under nitrogen for 2.2-2.8 h, and after stopping the stirring, the mixture is allowed to stand for 1.2-1.8 h for degassing to obtain a spinning solution.

[0087] The spinning solution is filtered through a filter and then extruded at an extrusion temperature of 162-167° C.; the spinning solution is then spun at a temperature of 143-147° C. and a spinneret aperture of 0.8-1.2 mm; the spun fibers are then stretched by airflow at a temperature of 138-142° C. and a stretching spinning speed of 180-230 m / min to form spun fibers; and the spun fibers are then cooled by air at a temperature of 9-12° C. to obtain polypropylene fibers.

[0088] The polypropylene fiber is soaked in ethanol for more than 12 hours, then washed with deionized water for at least 3 times to remove impurities adsorbed on the surface of the polypropylene fiber, and then placed in an oven and dried at 70°C for 24-32 hours to remove moisture; the dried polypropylene fiber is immersed in an acrylic acid solution at room temperature, wherein the solvent of the acrylic acid solution is ethanol and the amount of acrylic acid used is 9-12 mol relative to 1 kg of polypropylene fiber, and the solution is immersed and shaken. After 2.5-3.5 hours, the solution is taken out and dried, and then placed in a microwave reactor for microwave irradiation grafting modification. The modification conditions include: microwave frequency of 2430-2470 MHz, microwave irradiation power of 700-900 W, and time of 17-23 minutes.

[0089] The modified polypropylene fiber is washed with deionized water for at least three times, and then dried at 68-72° C.; and then the fiber is carded into a web, needle-punched, and heat-sealed to obtain a grafted modified web with a three-dimensional network structure.

[0090] (2) The grafted modified omentum is compacted and loaded into the bed of the oil-water separator in layers, wherein the ratio of the loading volume of the surface modified omentum to the volume of the oil-water separator is 1:2.5-3.5;

[0091] (3) Pumping the oily wastewater in the storage tank at a temperature of 40-60°C into the wastewater tank through a wastewater pump;

[0092] (4) Open the flow regulating valve and flow meter, and pump the liquid in the sewage tank into the oil-water separator through the feed pump. By adjusting the flow regulating valve, the flow rate is controlled to be 0.1-0.3m / s relative to the grafted modified membrane with a filling volume of 300L. 3 / h, to treat oily wastewater, the separated oil phase enters the oil collecting tank through the oil phase outlet, and the water phase without the oil phase enters the water production tank through the water phase outlet.

[0093] The present invention will be described in detail below by way of examples. In the following examples and test examples:

[0094] Antioxidant 1010, composed of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate];

[0095] Antioxidant 168, composed of tris(2,4-di-tert-butyl)phenyl phosphite;

[0096] Antioxidant 1076, composed of β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate;

[0097] Antioxidant 264, composed of 2,6-di-tert-butyl-4-methylphenol;

[0098] Antioxidant 1024, composed of N,N'-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine;

[0099] The antioxidant TPP is composed of triphenyl phosphite.

[0100] The polypropylene melt index is measured using the ASTM D1238-13 method at a temperature of 230° C. and a load weight of 2.16 kg.

[0101] The test method of the gram weight is as follows: first take a sample with a gram weight tester, then weigh it with a balance, and the number of grams obtained is divided by the area to obtain the gram weight (g / m 2 ).

[0102] The porosity was measured by mercury intrusion using an Autopore IV-9500 fully automatic mercury intrusion instrument.

[0103] The tensile strength was tested using a 3342 universal material testing machine from INSTRON, USA. The total length of the specimen was 40 mm, the test temperature was 25 °C, and the loading speed was 40 mm / min.

[0104] The oil content in water is determined according to the national standard GB / T16488-1996 Water quality - Determination of petroleum, animal and vegetable oils.

[0105] The oil removal rate is calculated as follows:

[0106] Wherein, C0 represents the oil content of the oily wastewater in the wastewater tank, in mg / L;

[0107] C represents the oil content of the water phase in the water production tank, in mg / L.

[0108] Furthermore, unless otherwise specified, the materials described are all commercially available.

[0109] like Figure 1As shown, the oily wastewater treatment device of the present invention comprises, in order of material flow, a liquid storage tank 1, a sewage pump 2, a sewage tank 3, a flow regulating valve 4, a flow meter 5, a feed pump 6, an oil-water separator 7, a water production tank 8, and an oil collection tank 9. Liquid storage tank 1 stores oily wastewater at a temperature of 40-60°C and is connected to sewage pump 2 via a pipeline. Sewage pump 2 is connected to the sewage tank inlet of sewage tank 3 via a pipeline and is used to pump the oily wastewater in liquid storage tank 1 into sewage tank 3. The sewage tank outlet of sewage tank 3 is connected to feed pump 6 via a pipeline, on which flow regulating valve 4 and flow meter 5 are sequentially installed. The feed pump is connected to the sewage inlet of oil-water separator 7 via a pipeline and is used to pump the wastewater in sewage tank 3 into oil-water separator 7 for treatment. Oil-water separator 7 is filled with a grafted modified mesh membrane to treat the oily wastewater, specifically separating the oil phase from the water phase. The oil-water separator includes an oil phase outlet and a water phase outlet. The oil phase outlet is connected to the oil collecting tank 9 through a pipeline, and the water phase outlet is connected to the water production tank 8 through a pipeline.

[0110] Examples 1-9 and Comparative Examples 1-2

[0111] (1) Polypropylene and an antioxidant are added to a spinning kettle equipped with a stirring device, mixed, and melted, and then stirred for a period of time under nitrogen flow. After stopping the stirring, the mixture is allowed to stand for degassing to obtain a spinning solution.

[0112] The spinning solution is filtered through a filter screen and then fed into a screw extruder through a pipeline for extrusion. The solution is then spun through a metering pump through the spinneret of a spinning assembly. The fibers are stretched by air flow to form nascent fibers, which are then cooled by air to obtain polypropylene fibers of uniform thickness.

[0113] (2) The polypropylene fiber was soaked in ethanol for more than 12 hours, then washed with deionized water three times to remove impurities adsorbed on the surface of the polypropylene fiber, and then placed in an oven to dry and remove moisture; the dried polypropylene fiber was immersed in a solution of vinyl functional monomer for 3 hours, taken out and dried, and then placed in a microwave reactor for microwave irradiation grafting modification.

[0114] (3) The modified polypropylene fibers are cleaned and dried, and a certain amount is weighed and then carded into a web, needle-punched, and heat-sealed to obtain a grafted modified web having a three-dimensional network structure.

[0115] The condition parameters of each step and each material parameter of Examples 1-9 and Comparative Examples 1-2, as well as the gram weight, thickness and porosity of the web are shown in Table 1-4.

[0116] Here, m (polypropylene resin: antioxidant) refers to the weight ratio of the polypropylene resin to the antioxidant.

[0117] Table 1

[0118]

[0119]

[0120] Table 2

[0121]

[0122] Table 3

[0123]

[0124]

[0125] Table 4

[0126] Example <![CDATA[Web weight (g / m 2 )]]> Membrane thickness (mm) Porosity (%) 1 380 30 80 2 500 50 65 3 360 40 78 4 400 50 55 5 380 40 60 6 200 60 70 7 350 40 68 8 100 80 85 9 700 20 20 Comparative Example 1 360 (unmodified) 40 78 Comparative Example 2 (Not forming a retina) - -

[0127] Test Case

[0128] The graft modified omentum prepared in Examples 1-9 and Comparative Examples 1-2 was taken and its tensile strength was measured respectively. The results are shown in Table 5.

[0129] Take the oily wastewater from a refinery, the pH of the wastewater is 7.0, and the oil content is 8362 mg / L.

[0130] Take the graft modified omentum prepared in Examples 1-9 and Comparative Examples 1-2, which have been used for more than 6 months before this test, and Figure 1 The oily wastewater is treated in the oily wastewater treatment device shown.

[0131] The specific method is:

[0132] (1) The products prepared in Examples 1-9 and Comparative Examples 1-2 were compacted and loaded into the bed of an oil-water separator in layers.

[0133] (2) Pump the oily wastewater in the storage tank at a temperature of 40-60°C into the wastewater tank through a wastewater pump;

[0134] (3) Open the flow regulating valve and flow meter, and pump the liquid in the sewage tank into the oil-water separator through the feed pump. By adjusting the flow regulating valve, the flow rate of the oily sewage is controlled to be 0.1-0.5m / s relative to the grafted modified membrane with a filling volume of 300L. 3 / h.

[0135] The specific operating conditions are shown in Table 5.

[0136] After stable operation, water from the production tank was collected, its oil content was measured, and the oil removal rate was calculated. The results are shown in Table 5.

[0137] The filling ratio is the ratio of the filling volume of the grafted modified omentum to the volume of the oil-water separator.

[0138] Table 5

[0139]

[0140] The above results demonstrate that the omentum prepared using the technical solution of the present invention still achieves a high oil removal rate during oil-water separation even after six months of operation, demonstrating that the omentum prepared using the technical solution of the present invention can maintain its efficient oil removal function for a long period of time. Furthermore, it can be seen that the tensile strength of the omentum prepared using the present invention is similar to that of the unmodified omentum in Comparative Example 1, but the oil removal effect is superior. This demonstrates that the technical solution of the present invention can achieve a higher oil-water separation effect without affecting the mechanical properties of the underlying material.

[0141] Furthermore, the omentum prepared using the technical solution of the present invention has a simple preparation process and is suitable for industrial-scale production. Furthermore, the oil-water separation process using the device of the present invention is safe and explosion-proof, has low operating costs, high efficiency, and does not generate waste residue or cause secondary pollution.

[0142] 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. A method for preparing a grafted modified omentum, characterized in that: The method includes: (1) melting polypropylene and an antioxidant to obtain a spinning solution, and spinning the spinning solution to obtain polypropylene fibers; (2) using vinyl functional monomers to modify polypropylene fibers by microwave irradiation to obtain modified polypropylene fibers; (3) forming a network of modified polypropylene fibers to obtain a grafted modified network membrane having a three-dimensional network structure; The conditions of the web forming process make the weight of the grafted modified web film be 350-400 g / m 2 , thickness of 40-50 mm, porosity of 55-78% by volume; Wherein, in step (1), according to the ASTM D1238-13 method, the melt index of the polypropylene at a temperature of 230° C. and a load weight of 2.16 kg is 500-700 g / 10 min and 1000 g / 10 min; Wherein, the spinning method further comprises: sequentially extruding, spinning, stretching and cooling the spinning solution; Wherein, the extrusion conditions include: temperature of 140-165°C; The spinning conditions include: a spinneret aperture of 0.5-1.5 mm and a temperature of 120-145° C. The stretching conditions include: air flow stretching, the air flow temperature is 120-140° C., and the stretching spinning speed is 100-300 m / min; The cooling conditions include: using air cooling, the air temperature is 10-16°C; Wherein, by weight, the usage ratio of the polypropylene to the antioxidant is 19-32.3:

1.

2. The method according to claim 1, wherein The antioxidant is selected from at least one of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, tris(2,4-di-tert-butyl)phenyl phosphite, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 2,6-di-tert-butyl-4-methylphenol, N,N'-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine and triphenyl phosphite.

3. The method according to claim 1, wherein The melting temperature is 175-200°C.

4. The method according to claim 1, wherein The method further comprises: stirring and degassing after melting.

5. The method according to claim 1, wherein The spinning conditions are such that the diameter of the polypropylene fiber is 10-60 μm.

6. The method according to claim 1, wherein In step (2), the modification method comprises: immersing the polypropylene fiber in a vinyl functional monomer solution, taking it out, and subjecting it to microwave irradiation.

7. The method according to claim 1, wherein The vinyl functional monomer is selected from at least one of acrylamide, propylene sulfonic acid, p-vinylbenzenesulfonic acid, acrylic acid, methacrylic acid, hydroxyethyl methacrylate and N-vinyl pyrrolidone.

8. The method according to claim 1, wherein The amount of the vinyl functional monomer used is 1-15 mol relative to 1 kg of polypropylene fiber.

9. The method according to claim 1, wherein In step (2), the microwave irradiation conditions include: microwave frequency of 2000-3000 MHz, microwave irradiation power of 100-2000 W, and time of 1-120 min.

10. The method according to claim 1, wherein: The web forming method comprises: sequentially performing carding, needle punching and heat sealing reinforcement.

11. A grafted modified omentum prepared by the method according to any one of claims 1 to 10.

12. Use of the grafted modified omentum according to claim 11 in treating oily wastewater.

13. A device for treating oily wastewater, comprising, in order according to the flow of the material: Liquid storage tank and oil-water separator; Wherein, the liquid storage tank is used to store oily wastewater; the oil-water separator is filled with the grafted modified mesh membrane according to claim 11 for oil-water separation; The oil-water separator is further connected to a water production tank and an oil collecting tank respectively. The water production tank is used to receive the water phase from the oil-water separator, and the oil collecting tank is used to receive the oil phase from the oil-water separator.

14. A method for treating oily wastewater, characterized in that: The method is carried out in the device according to claim 13, and comprises: introducing the oily wastewater in the liquid storage tank into the oil-water separator to separate the oil and water.

15. The method according to claim 14, wherein In the oil-water separator, the ratio of the filling volume of the grafted modified omentum to the volume of the oil-water separator is 1:2-4.

16. The method according to claim 14, wherein In the oil-water separator, relative to the graft modified membrane with a filling volume of 300L, the oily wastewater inlet speed is 0.1-0.5m 3 / h.

17. The method according to claim 14, wherein: The temperature of the oily wastewater is 40-60°C.

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