Oil-water emulsion treatment particles as well as preparation method and application thereof

Abstract

The invention discloses oil-water emulsion treatment particles and a preparation method and application thereof, the particles comprise super-hydrophilic modified particles and super-hydrophobic modified particles, the particle size range of the super-hydrophilic modified particles and / or the super-hydrophobic modified particles is 20-80 meshes, and the mass ratio of the super-hydrophilic modified particles to the super-hydrophobic modified particles is (0.5-5): (0.5-5). The particles provided by the invention can deeply coalesce and separate dispersed phase liquid drops in the oil-water emulsion, and can efficiently treat the oil-water emulsion.

Description

Technical Field

[0001] The invention relates to the technical field of oil-water separation materials, and more particularly to an oil-water emulsion treatment particle and a preparation method and application thereof. Background Art

[0002] Oily wastewater is constantly produced in the production of petrochemical, pharmaceutical, catering, steel processing, textile and other industries, which seriously endangers the ecosystem and human health and further aggravates the problem of water shortage. In the process of sewage treatment, the separation of oil-water emulsion is an inevitable and important step. How to destroy the stability of the emulsion system and make it two immiscible phases has always been a difficult problem that troubles people. Today, when sustainable development is advocated, green and efficient oil-water mixture and emulsion separation materials and technologies are urgently needed.

[0003] With the development of interface theory, the separation technology of special wettability materials has become one of the most promising methods in oil-water emulsion processing due to its high efficiency and simplicity. According to the different wettability of oil-water separation materials, they are mainly divided into super-hydrophobic-super-oleophilic materials and super-hydrophilic-underwater super-oleophobic materials. Among them, although super-hydrophobic-super-oleophilic materials have a good separation effect on oil-water mixtures, when separating oil-water emulsions, they can only adsorb the oil phase they come into contact with, and cannot significantly improve the separation efficiency of the emulsion. Due to the adhesion of the oil phase, the pores of super-hydrophilic underwater super-oleophobic materials are easily blocked by the oil phase during the actual separation process, resulting in a decrease in separation efficiency.

[0004] For example, Chinese patent CN115254053A discloses a method for preparing hydrophobically modified quartz sand, by coating a layer of honeycomb mesoporous SiO on the surface of quartz sand. 2 , and then PDMS was used to modify its hydrophobicity to obtain hydrophobic and oleophilic quartz sand, which increased the oil removal rate of oily wastewater from 58.2% to 86.9%, but the separation efficiency was limited. Chinese patent CN112169375A discloses a super-hydrophilic underwater super-oleophobic particle for oily wastewater treatment and its preparation and application method. The underwater super-oleophobic property is due to the super-hydrophilicity of the surface obtained by the micro-nano secondary hydrophilic rough structure. After adsorbing a layer of water film, it has a strong repulsive effect on oil, effectively overcoming the disadvantage that the super-hydrophobic-super-oleophilic oil-water separation material is easily contaminated by oil and causes membrane pore blockage, but it is still inevitable that the particles will be corroded by the oil phase after long-term use, resulting in a decrease in separation efficiency. Summary of the invention

[0005] To solve the above problems, the present invention provides an oil-water emulsion processing particle and a preparation method thereof, wherein the particle can deeply aggregate and separate the dispersed phase in the oil-water emulsion, and can efficiently separate and process the oil-water emulsion.

[0006] First, one of the objectives of the present invention is to provide a kind of particle for treating oil-water emulsion.

[0007] Specifically, the particle for treating oil-water emulsion provided by the present invention comprises super-hydrophilic modified particles and super-hydrophobic modified particles. Among them, the particle size range of the super-hydrophilic modified particles and / or the super-hydrophobic modified particles is 20 - 80 mesh, preferably 40 - 80 mesh, and the mass ratio of the super-hydrophilic modified particles to the super-hydrophobic modified particles is 0.5 - 5:0.5 - 5, preferably 1 - 4:1 - 4, and more preferably 2 - 3:1.

[0008] Furthermore, the super-hydrophilic modified particles are inorganic particles wrapped with a hydrophilic coating, and the hydrophilic coating is made of a hydrophilic polymer. Among them, the hydrophilic polymer is selected from one of polyvinyl alcohol and chitosan.

[0009] Furthermore, the super-hydrophobic modified particles are inorganic particles wrapped with a hydrophobic coating, and the hydrophobic coating is made of a hydrophobic polymer. The hydrophobic polymer is selected from one of polytetrafluoroethylene, polyvinylidene fluoride, and polypropylene.

[0010] Preferably, the particle size ranges of the super-hydrophilic modified particles and the super-hydrophobic modified particles are the same or different. More preferably, the particle size range of the modified particles that the dispersed phase of the oil-water emulsion to be separated is hydrophilic to is smaller than the particle size range of the modified particles that the continuous phase of the oil-water emulsion to be separated is hydrophilic to.

[0011] Furthermore, the inorganic particles are one or a combination of quartz sand, garnet, and zeolite.

[0012] Secondly, the second objective of the present invention is to provide a preparation method of the particle for treating oil-water emulsion of the first objective of the present invention.

[0013] Specifically, the method includes the steps of coating a hydrophilic coating on the inorganic particles to obtain super-hydrophilic modified particles, coating a hydrophobic coating on the inorganic particles to obtain super-hydrophobic modified particles, and mixing the super-hydrophilic modified particles and the super-hydrophobic particles.

[0014] Furthermore, the preparation method of the super-hydrophilic modified particles includes the following steps:

[0015] S1.1. After cleaning, removing impurities, and drying the inorganic particles A, clean inorganic particles A are obtained;

[0016] S1.2. Mix the hydrophilic polymer with water to obtain an aqueous solution of the hydrophilic polymer. Immerse the clean inorganic particles A in the aqueous solution of the hydrophilic polymer, stir, filter, and dry to obtain particles coated with the hydrophilic polymer;

[0017] Optionally, the method further includes S1.3, dissolving a small amount of glutaraldehyde in a mixture of ethanol and water, adding a small amount of hydrochloric acid and the hydrophilic polymer-coated particles obtained in step S1.2 thereto, and after sufficient stirring and mixing, cross-linking and curing under dry conditions to obtain super-hydrophilic modified particles.

[0018] More specifically, the preparation method comprises the following steps:

[0019] S1.1, rinse the inorganic particles A with water, then ultrasonically wash them with 1M NaOH, distilled water, and ethanol in sequence to remove impurities, and finally dry them to obtain clean inorganic particles A;

[0020] S1.2, mixing a certain proportion of a hydrophilic polymer with water, stirring at high temperature to obtain a uniform hydrophilic polymer aqueous solution, then immersing clean inorganic particles A in the solution, stirring, filtering, and drying to obtain hydrophilic polymer-coated particles;

[0021] Optionally, S1.3, a small amount of glutaraldehyde is dissolved in a mixture of ethanol and water, a small amount of hydrochloric acid and hydrophilic polymer-coated particles are added thereto, and after sufficient stirring and mixing, the mixture is cross-linked and cured under dry conditions to obtain super-hydrophilic modified particles.

[0022] Preferably, in step S1.1, the inorganic particles A are selected from one or a combination of quartz sand, garnet, and zeolite; more preferably, the particle size range of the inorganic particles A is 20 to 80 mesh, preferably 40 to 80 mesh. The hydrophilic coating is very thin, so the particle size range of the obtained super-hydrophilic modified particles is basically consistent with the particle size range of the inorganic particles A raw material itself.

[0023] Preferably, in step S1.2, the hydrophilic polymer is selected from one of polyvinyl alcohol and chitosan; the mass concentration of the hydrophilic polymer aqueous solution is 1-6wt%, preferably 2-4wt%; the mass ratio of the clean inorganic particles A to the hydrophilic polymer aqueous solution is 1:10-20, preferably 1:12-15.

[0024] It is worth mentioning that the above hydrophilic polymers are all from commercially available products.

[0025] Preferably, the conditions for preparing the super-hydrophilic modified particles are: stirring the clean inorganic particles A in the hydrophilic polymer aqueous solution for more than 30 minutes; and drying at a temperature of 60 to 80°C.

[0026] Preferably, in step S1.3, the mass concentration of the glutaraldehyde solution is 0.1-3wt%, preferably 0.2-2wt%; the mass ratio of ethanol to water is 0-3:5, preferably 1-2:5; the mass ratio of the clean granular material A to the glutaraldehyde solution is 5-20:1, preferably 10-15:1.

[0027] Preferably, in step S1.3, the conditions for the crosslinking and curing reaction are as follows: the pH of the reaction system is 2 to 5; the reaction temperature is 80 to 120 °C; the reaction time is more than 10 h.

[0028] Furthermore, the preparation method of the superhydrophobic modified particles includes the following steps:

[0029] S2.1. After washing, impurity removal, and drying of inorganic particle B, clean inorganic particle B is obtained;

[0030] S2.2. A hydrophobic polymer is added to a solvent, and clean inorganic particle B is added thereto. After stirring, drying, and heat treatment, particles coated with a hydrophobic coating are obtained.

[0031] More specifically, the preparation method includes the following steps:

[0032] S2.1. Inorganic particle B is rinsed with water, then ultrasonically washed successively with 1M NaOH, distilled water, and ethanol to remove impurities, and finally dried at 80 °C to obtain clean inorganic particle B;

[0033] S2.2. A certain amount of hydrophobic polymer is added to a solvent and stirred evenly, then clean inorganic particle B is added thereto. After stirring, drying, and heat treatment, superhydrophobic modified particles are obtained.

[0034] Preferably, in step S2.1, inorganic particle B is selected from one or a combination of quartz sand, garnet, and zeolite; more preferably, the particle size of inorganic particle B is 20 to 80 mesh, preferably 40 to 80 mesh. Since the hydrophobic coating is very thin, the particle size range of the obtained superhydrophobic modified particles is basically the same as that of the inorganic particle B raw material itself.

[0035] Preferably, in step S2.2, the hydrophobic polymer is selected from one of polytetrafluoroethylene, polyvinylidene fluoride, and polypropylene; the solvent is water or N,N-dimethylformamide; the mass concentration of the hydrophobic polymer solution is 20 to 40 wt%; the mass ratio of clean inorganic particle B to the hydrophobic polymer solution is 1:8 to 20, preferably 1:10 to 15.

[0036] It is worth mentioning that the hydrophobic polymer in the present invention can be a commercially available product. For example, polytetrafluoroethylene can be a water dispersion of polytetrafluoroethylene, preferably from a water-soluble dispersion with a concentration of 70%.

[0037] More preferably, the conditions for preparing the superhydrophobic modified particles are as follows: clean inorganic particle B is stirred in the hydrophobic polymer solution at room temperature for more than 30 min; the drying temperature condition is 60 to 100 °C for more than 8 h.

[0038] Thirdly, the third object of the present invention is to provide a filter bed device for treating oil-water emulsion.

[0039] Specifically, the filter bed device includes a filter column filled with the oil-water emulsion treatment particles of one of the objects of the present invention, or the oil-water emulsion treatment particles prepared by the preparation method of the second object of the present invention.

[0040] Preferably, the filling height of the filter column is greater than or equal to 5 cm, preferably greater than or equal to 10 cm.

[0041] Finally, the fourth object of the present invention is to provide an application of the oil-water emulsion treatment particles of one of the objects of the present invention.

[0042] Specifically, the oil-water emulsion treatment particles of the present invention can be filled into a filter column as a filter layer for separating oil-water emulsion, including the following steps:

[0043] Place a strong mesh structure that can carry the filter material at the bottom of the filter column. After uniformly mixing superhydrophilic modified particles and superhydrophobic modified particles with different mass ratios and different particle sizes according to the content of the oil-water emulsion, fill them into the filter column as a filter layer and compact and fix them. Pour the oil-water emulsion into the mixed filter layer for separation. Among them, the droplets of the dispersed phase will be trapped inside the filter layer, thereby realizing the demulsification and separation of the oil-water emulsion.

[0044] The principle of separating oil-water emulsion by the combined filter layer of the above-mentioned superhydrophilic modified particles and superhydrophobic modified particles is as follows: When two kinds of particles with different wettabilities are evenly distributed in the combined filter layer, two kinds of pores will be formed, one is the pore between particles with the same wettability, and the other is the pore between particles with different wettabilities. When the continuous phase in the oil-water emulsion enters the combined filter layer, it will continuously seep out through the pores. The small droplets as the dispersed phase will continuously contact the surface of the particles with the same wettability due to the complex pores between the particles and the action of the fluid, and then be adsorbed and trapped on the particle surface to achieve demulsification.

[0045] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0046] 1. The superhydrophilic modified particles and superhydrophobic modified particles prepared by the present invention have stable special wettability. The granular matrix material can flexibly adjust the particle size and wettability ratio. The preparation process is simple, the material is green and pollution-free, the application scenario is flexible, and it can be reused, which has significant advantages compared with traditional particle materials.

[0047] 2. The two kinds of special wettability particles prepared by the present invention can effectively adsorb and separate the dispersed phase in the oil-water mixture, and the combined particle filter layer formed by them can greatly improve the separation efficiency of the oil-water emulsion, and has broad application prospects in the field of oil-water emulsion treatment.

[0048] 3. The present invention separately prepares superhydrophilic particles and superoleophilic particle materials, which have good durability and a simple preparation process. By utilizing the advantages of the pore structure and wettability difference of the particle materials, a combined filtration method of superhydrophilic and superoleophilic particles for deep coalescence separation of droplets in an oil-water emulsion is provided, so as to achieve the purpose of efficient treatment of the oil-water emulsion. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 It is a field emission scanning electron microscope image of two modified quartz sand particles prepared in Example 1 of the present invention at different magnifications. Among them, a - c are original quartz sand particles, d - f are superhydrophilic quartz sand modified particles, and g - i are superhydrophobic quartz sand modified particles;

[0050] Figure 2 It is an optical image of the oil and water contact angles of two modified quartz sand particles prepared in Example 1 of the present invention. Among them, a is a schematic diagram of the different contact angles of the superhydrophilic quartz sand modified particle with oil and water, and b is a schematic diagram of the different contact angles of the superhydrophobic quartz sand modified particle with oil and water;

[0051] Figure 3 It is a schematic diagram of the adsorption of an oil-water mixture by two modified quartz sand particles prepared in Example 1 of the present invention. Among them, a - b are schematic diagrams of the adsorption process of water in the oil-water mixture by the superhydrophilic modified particle, and c - d are schematic diagrams of the adsorption process of oil in the oil-water mixture by the superhydrophobic modified particle;

[0052] Figure 4 It is a schematic diagram of the separation effect of the filter layer formed by mixing two modified quartz sand particles prepared in Example 1 of the present invention in different mass ratios on the water-in-oil emulsion; the abscissa in the figure is the mass ratio of the two modified quartz sand particles; the left ordinate is the separation efficiency (%), and the right ordinate is the separation flux (Lm -2 h -1 )

[0053] Figure 5 It is a schematic diagram of the separation effect of the filter layer formed by mixing two modified quartz sand particles prepared in Example 1 of the present invention on different types of water-in-oil emulsions; the abscissa in the figure is different types of oil-water emulsions; the left ordinate is the separation efficiency (%), and the right ordinate is the separation flux (Lm -2 h -1 )

[0054] Figure 6 It is a schematic diagram of the separation effect of the filter layer formed by mixing two modified quartz sand particles prepared in Example 1 of the present invention in different mass ratios on the oil-in-water emulsion; the abscissa in the figure is the mass ratio of the two modified quartz sand particles; the left ordinate is the separation efficiency (%), and the right ordinate is the separation flux (Lm -2 h -1 )

[0055] Figure 7 Schematic diagram of the separation effect of the filter layer formed by mixing two kinds of modified quartz sand particles prepared in Example 1 of the present invention on different types of water-in-oil emulsions; in the figure, the abscissa is different types of oil-water emulsions; the left ordinate is the separation efficiency (%), and the right ordinate is the separation flux (Lm -2 h -1 );

[0056] Figure 8 Schematic diagram of the separation of emulsion by filling two kinds of modified quartz sand particles prepared in Example 1 of the present invention into a filter column. Detailed implementation manners

[0057] The present invention will be specifically described below with reference to specific drawings and examples. It is necessary to point out here that the following examples are only for further illustration of the present invention and cannot be construed as limiting the protection scope of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention still fall within the protection scope of the present invention.

[0058] In the following examples and comparative examples, the raw materials are all commercially available products.

[0059] Example 1

[0060] This example is used to illustrate the preparation of super-hydrophilic modified quartz sand particles and super-hydrophobic modified quartz sand particles.

[0061] Wash different mesh sizes of quartz sand raw materials with water, and then ultrasonically wash them with 1M NaOH, distilled water, and ethanol for 3 h in sequence to remove impurities. Finally, dry them in an oven at 80 °C for 6 h to obtain clean quartz sand.

[0062] The following is used to illustrate the preparation of super-hydrophilic modified quartz sand particles:

[0063] First, mix polyvinyl alcohol with water and stir at 90 °C for 6 h to obtain an aqueous polyvinyl alcohol solution (concentration 4 wt%). Then, soak and stir clean 40-80 mesh quartz sand in the aqueous polyvinyl alcohol solution for 1 h, filter, and dry at 80 °C. Put the dried quartz sand into an aqueous solution of glutaraldehyde (concentration 2 wt%) and a small amount of HCl (pH = 3) and soak and stir for 30 min. Take out the quartz sand and crosslink and cure it in an oven at 80 °C for 12 h to completely cure polyvinyl alcohol and glutaraldehyde on the surface of the quartz sand, forming a complete coating, and obtaining super-hydrophilic quartz sand particles.

[0064] Figure 1 (d-f) show the field emission scanning electron microscope images (SEM) of the original quartz sand particles and the super-hydrophilic quartz sand modified particles prepared in this example at different magnifications. Among them, Figure 1a to c are of the original quartz sand particles, Figure 1 d to f are of the super-hydrophilic quartz sand modified particles. Obvious differences can be observed through comparison, especially Figure 1 By comparing figure c and figure f, the layered structure formed on the surface of the quartz sand after being coated with polyvinyl alcohol / glutaraldehyde can be clearly observed, proving the success of the modification.

[0065] Figure 2 (a) shows the optical pictures of the oil-water contact angles of the super-hydrophilic quartz sand modified particles prepared in this example. From Figure 2 a, the different contact angles of the super-hydrophilic quartz sand modified particles with oil and water under different environments can be observed. Among them, under air conditions, the contact angles of the super-hydrophilic quartz sand modified particles with water and oil are both 0°; under water conditions, the contact angle with oil is about 152°; under oil, the contact angle with water is 0°, proving that the super-hydrophilic quartz sand modified particles have super-hydrophilic-underwater super-oleophobic properties.

[0066] Figure 3 (a - b) shows the schematic diagrams of the water adsorption process of the super-hydrophilic quartz sand modified particles prepared in this example for the water in the oil-water mixture. Among them, Figure 3 a is that the super-hydrophilic particles adsorb the water in the heavy oil / water mixture, and the water accumulates in the upper layer. After adding the super-hydrophilic modified particles, the water in the upper layer is quickly adsorbed and aggregated into clusters, and quickly sinks to the bottom of the glass bottle. After filtering the particles, clean oil can be obtained; Figure 3 b is that the super-hydrophilic particles adsorb the water in the light oil / water mixture, and the water accumulates in the lower layer. After adding the super-hydrophilic modified particles, the water in the lower layer is quickly absorbed. After filtering the particles, clean oil can be obtained. It can be seen that the super-hydrophilic modified particles can effectively remove the water in the oil-water mixture.

[0067] The following is used to illustrate the preparation of the super-hydrophobic modified quartz sand particles:

[0068] Add the polytetrafluoroethylene dispersion liquid into water and stir for 0.5 h to obtain a uniform polytetrafluoroethylene aqueous solution (concentration 30 wt%). Immerse the clean 40 - 80 mesh quartz sand into it, ultrasonically disperse for 30 min, dry at 80 °C for 4 h, and finally heat-treat at 380 °C for 2 h to obtain the super-hydrophobic quartz sand particles.

[0069] Figure 1 (g - i) shows the field emission scanning electron microscope images (SEM) of the original quartz sand particles and the super-hydrophobic quartz sand modified particles prepared in this example at different magnifications. Among them, Figure 1 a to c are of the original quartz sand particles, Figure 1 g to i are of the super-hydrophobic quartz sand modified particles. Obvious differences can be observed through comparison, especially Figure 1By comparing Figure c and Figure i, the staggered striped structure formed on the surface of quartz sand after being coated with polytetrafluoroethylene can be clearly observed, proving the success of the modification.

[0070] Figure 2 (b) shows the optical pictures of the oil and water contact angles of the superhydrophobic quartz sand modified particles prepared in this example. From Figure 2 b, it can be observed that the superhydrophobic quartz sand modified particles have different contact angles with oil and water in different environments. Among them, under air conditions, the contact angle between the superhydrophobic quartz sand modified particles and water is about 153°, and the contact angle with oil is 0°. The oil droplets can completely wet the particles; underwater, the contact angle with oil is also 0°; under oil conditions, the contact angle with water is about 151°, proving that the superhydrophobic quartz sand modified particles have superhydrophobic-superoleophilic properties.

[0071] Figure 3 (c, d)) shows the schematic diagram of the oil adsorption process of the superhydrophobic quartz sand modified particles prepared in this example for the oil in the oil-water mixture. Among them, Figure 3 c is the superhydrophobic particles adsorbing the oil in the light oil / water mixture. The oil accumulates in the upper layer. After adding the superhydrophobic quartz sand modified particles, the oil in the upper layer is quickly adsorbed, and the oil sand sinks to the bottom of the glass bottle. After filtering the particles, clean water can be obtained; Figure 3 d is the superhydrophobic particles adsorbing the oil in the heavy oil / water mixture. The oil accumulates in the lower layer. After adding the superhydrophobic quartz sand modified particles, the oil in the lower layer is quickly absorbed. It can be seen that the superhydrophobic modified particles can effectively remove the oil in the oil-water mixture.

[0072] The following is used to illustrate the separation effect of the oil-water emulsion by using the above two kinds of modified mixed particles as the filter layer filled in the filter column of the filter bed device.

[0073] Filling of the filter column (as Figure 8 shown): Place a strong mesh structure that can carry the filter material at the bottom of the filter column with a diameter of 5 cm. Uniformly mix the above-prepared superhydrophilic modified quartz sand particles and superhydrophobic modified quartz sand particles, and fill them into the filter column as filter materials and compact and fix them. The height of the filled mixed particles is 10 cm.

[0074] Among them, the two kinds of particles are combined and applied in the following two component ways:

[0075] Combination 1: Separation test of the water-in-oil emulsion with an oil content of 1000 mg / L after filling the filter column with superhydrophilic modified quartz sand particles and superhydrophobic modified quartz sand particles in different mass ratios.

[0076] Figure 4 shows the separation effect of the water-in-oil emulsion by the filter layer formed by mixing the above two kinds of modified quartz sand particles in different mass ratios. From Figure 4It can be seen that the composite particles all have good separation efficiency and separation flux for oil-in-water emulsions, and the combination of hydrophilic particles: hydrophobic particles = 2 - 3:1 is more optimal.

[0077] A filter column with superhydrophilic modified particles: superhydrophobic modified particles = 3:1 was used to test the separation effect of water-in-oil emulsions of different types of oils (white oil W / tetrachloroethylene T / silicone oil W / diesel oil D).

[0078] Figure 5 The schematic diagram of the separation effect of different types of oil-in-water emulsions after mixing two kinds of modified quartz sand particles is shown. It can be seen from the figure that the composite particles all have good separation effect and separation flux for oil-in-water emulsions of different types of oils, and the separation effect is stable above 98%. During the filtration process, the superhydrophilic particles act as water channels for water filtration, while the superhydrophobic particles act as capture sites to capture and coalesce oil droplets, realizing the demulsification of oil-in-water emulsions.

[0079] Combination two: The separation test of water-in-oil emulsion with a water content of 1000 mg / L was carried out after filling a filter column with superhydrophilic modified quartz sand particles and superhydrophobic modified quartz sand particles combined in different mass ratios.

[0080] Figure 6 The schematic diagram of the separation effect of the filter layer formed by mixing the above two kinds of modified quartz sand particles in different mass ratios on water-in-oil emulsion is shown. From Figure 6 It can be seen that the composite particles have good separation efficiency and separation flux for water-in-oil emulsions, and the combination is more optimal when the hydrophilic particles: hydrophobic particles = 1:2 - 3.

[0081] A filter column with superhydrophilic modified particles: superhydrophobic modified particles = 1:3 was used to test the separation effect of oil-in-water emulsions of different types of oils (white oil W / tetrachloroethylene T / silicone oil W / diesel oil D).

[0082] Figure 7 The schematic diagram of the separation effect of different types of oil-in-water emulsions after mixing two kinds of modified quartz sand particles is shown. It can be seen from the figure that the composite particles all have good separation effect and separation flux for oil-in-water emulsions of different types of oils, and the separation effect is stable above 98%. During the filtration process, the superhydrophobic particles act as oil channels for oil filtration, while the superhydrophilic particles act as capture sites to capture and coalesce water droplets, realizing the demulsification of oil-in-water emulsions.

[0083] Example 2

[0084] This example is used to illustrate the preparation of superhydrophilic modified garnet particles and superhydrophobic modified garnet particles.

[0085] The garnet raw materials with different mesh numbers are rinsed clean with water, and then ultrasonically washed with 1M NaOH, distilled water, and ethanol for 3h in sequence to remove impurities. Finally, they are dried in an oven at 80 °C for 6h to obtain clean garnet.

[0086] The following is used to illustrate the preparation of superhydrophilic modified garnet particles:

[0087] First, chitosan is mixed with water and stirred at 90 °C for 6h to obtain a chitosan aqueous solution (concentration 2wt%). Then, the clean garnet with 20 - 30 mesh is soaked and stirred in the chitosan aqueous solution for 30min, filtered, and the garnet is placed in an oven at 80 °C for 12h to completely solidify the chitosan on the surface of the garnet, forming a complete coating layer to obtain superhydrophilic garnet particles.

[0088] The following is used to illustrate the preparation of superhydrophobic modified garnet particles:

[0089] Polyvinylidene fluoride is added to N,N - dimethylformamide and stirred for 0.5h to obtain a uniform polytetrafluoroethylene solution (concentration 40wt%). The clean garnet with 50 - 80 mesh is immersed in it, ultrasonically dispersed for 30min, and then dried at 80 °C for 4h to obtain superhydrophobic garnet particles.

[0090] The following is used to illustrate the effect of using the mixed particles modified by the above two methods as the filter layer filled in the filter column of the filter bed device for separating oil - in - water emulsions.

[0091] Filling of the filter column: A solid mesh structure capable of carrying the filter material is placed at the bottom of the filter column with a diameter of 5 cm. The superhydrophilic modified garnet particles and superhydrophobic modified garnet particles prepared above are uniformly mixed and filled into the filter column as the filter material and compacted and fixed. The total height of the filled mixed particles is 20 cm. Among them, the mass ratio of the superhydrophilic modified particles to the superhydrophobic modified particles is 4:1.

[0092] The oil - in - water emulsion with an oil content of 1000 - 1500 ppm is poured into the combined filter layer for separation.

[0093] In this example, the superhydrophilic particles act as water channels for water filtration, while the superhydrophobic particles act as capture sites to capture and coalesce oil droplets, realizing the demulsification of the oil - in - water emulsion, and its separation efficiency is stable above 98%.

[0094] Example 3

[0095] This example is used to illustrate the preparation of superhydrophilic modified zeolite particles and superhydrophobic modified zeolite particles.

[0096] Wash the zeolite raw materials with different mesh numbers clean with water respectively, then ultrasonically wash them with 1M NaOH, distilled water and ethanol successively for 3 h to remove impurities, and finally dry them in an oven at 80 °C for 6 h to obtain clean zeolite.

[0097] The following is used to illustrate the preparation of superhydrophilic modified zeolite particles:

[0098] First, mix polyvinyl alcohol with water and stir at 90 °C for 6 h to obtain an aqueous polyvinyl alcohol solution (concentration 3 wt%). Then soak the clean zeolite with 40 - 80 mesh in the aqueous polyvinyl alcohol solution and stir for 30 min, filter, and dry at 80 °C. Put the dried zeolite into an aqueous solution of glutaraldehyde (concentration 1.5 wt%) and a small amount of HCl (pH = 5) and soak and stir for 30 min. Take out the zeolite and crosslink and cure it in an oven at 80 °C for 12 h to completely cure the polyvinyl alcohol and glutaraldehyde on the zeolite surface to form a complete coating layer, thus obtaining superhydrophilic zeolite particles.

[0099] The following is used to illustrate the preparation of superhydrophobic modified zeolite particles:

[0100] Add polypropylene to N,N - dimethylformamide and stir for 0.5 h to obtain a uniform polypropylene solution (concentration 20 wt%). Immerse the clean zeolite with 40 - 80 mesh in it, ultrasonically disperse for 30 min, and then dry at 80 °C for 12 h to obtain superhydrophobic zeolite particles.

[0101] The following is used to illustrate the effect of using the mixed particles modified by the above two methods as the filter layer and filling them into the filter column of the filter bed device for the separation of oil - in - water emulsion.

[0102] Filling of the filter column: Place a firm mesh structure that can carry the filter material at the bottom of the filter column with a diameter of 5 cm. Uniformly mix the above - prepared superhydrophilic modified particles and superhydrophobic modified particles, fill them into the filter column as filter material and compact and fix them. The total height of the filled mixed particles is 10 cm. Among them, the mass ratio of the superhydrophilic modified particles to the superhydrophobic modified particles is 1:2.

[0103] Pour the water - in - oil emulsion with a water content of 500 - 1000 ppm into the combined filter layer for separation.

[0104] In this example, the superhydrophobic particles act as oil channels for oil filtration, while the superhydrophilic particles act as capture sites to capture and coalesce water droplets, realizing the demulsification of the water - in - oil emulsion, and its separation efficiency is stable above 97%.

[0105] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. An oil-water emulsion treatment particle, comprising a super-hydrophilic modified particle and a super-hydrophobic modified particle, wherein the particle size range of the super-hydrophilic modified particle and / or the super-hydrophobic modified particle is 20 to 80 mesh, preferably 40 to 80 mesh, and the mass ratio of the super-hydrophilic modified particle to the super-hydrophobic modified particle is 0.5 to 5:0.5 to 5, preferably 1 to 4:1 to 4, more preferably 2 to 3:

1.

2. The oil-water emulsion treatment particle according to claim 1, wherein, the super-hydrophilic modified particle is an inorganic particle wrapped with a hydrophilic coating; and / or, the super-hydrophobic modified particle is an inorganic particle wrapped with a hydrophobic coating; and / or, the particle size ranges of the super-hydrophilic modified particle and the super-hydrophobic modified particle are the same or different, preferably the particle size range of the modified particle that the dispersed phase of the oil-water emulsion to be separated is hydrophilic is smaller than the particle size range of the modified particle that the continuous phase of the oil-water emulsion to be separated is hydrophilic.

3. The oil-water emulsion treatment particle according to claim 2, wherein, the hydrophilic coating is made of a hydrophilic polymer, and the hydrophilic polymer is selected from one of polyvinyl alcohol and chitosan; and / or, the hydrophobic coating is made of a hydrophobic polymer, and the hydrophobic polymer is made of one selected from polytetrafluoroethylene, polyvinylidene fluoride, and polypropylene; and / or, the inorganic particle is one or a combination of quartz sand, garnet, and zeolite.

4. The preparation method of the oil-water emulsion treatment particle according to any one of claims 1 to 3, comprising the steps of coating the hydrophilic coating outside the inorganic particle to obtain the super-hydrophilic modified particle, coating the hydrophobic coating outside the inorganic particle to obtain the super-hydrophobic modified particle, and mixing the super-hydrophilic modified particle and the super-hydrophobic particle.

5. The preparation method according to claim 4, wherein, the preparation method of the super-hydrophilic modified particle comprises the following steps: S1.

1. After cleaning, impurity removal, and drying of the inorganic particle A, a clean inorganic particle A is obtained; S1.

2. Mix the hydrophilic polymer with water to obtain an aqueous solution of the hydrophilic polymer, soak the clean inorganic particle A in the aqueous solution of the hydrophilic polymer, stir, filter, and dry to obtain the super-hydrophilic modified particle; Optionally, it further comprises S1.

3. Dissolve a small amount of glutaraldehyde in a mixed solution of ethanol and water, add a small amount of hydrochloric acid and the particle coated with the hydrophilic polymer obtained in step S1.2 thereto, and after sufficient stirring and mixing, carry out crosslinking and curing under dry conditions to obtain the super-hydrophilic modified particle; Preferably, in step S1.3, the mass concentration of the glutaraldehyde solution is 0.1 to 3 wt%, preferably 0.2 to 2 wt%; the mass ratio of ethanol to water is 0 to 3:5, preferably 1 to 2:5; the mass ratio of the clean particle material A to the glutaraldehyde solution is 5 to 20:1, preferably 10 to 15:1; More preferably, in step S1.3, the conditions of the crosslinking and curing reaction are: the pH of the reaction system is 2 to 5; the reaction temperature is 80 to 120 °C; the reaction time is more than 10 h.

6. The preparation method according to claim 5, wherein, The inorganic particle A is selected from one or a combination of quartz sand, garnet, and zeolite; The particle size range of the inorganic particle A is 20 - 80 mesh, preferably 40 - 80 mesh.

7. According to the preparation method described in claim 5, It is characterized in that The hydrophilic polymer is selected from one of polyvinyl alcohol and chitosan; The mass concentration of the hydrophilic polymer aqueous solution is 1 - 6 wt%, preferably 2 - 4 wt%; The mass ratio of the inorganic particle A to the hydrophilic polymer aqueous solution is 1:10 - 20, preferably 1:12 - 15.

8. According to the preparation method described in claim 4, It is characterized in that The preparation method of the superhydrophobic modified particles comprises the following steps: S2.

1. After cleaning, impurity removal, and drying of the inorganic particle B, clean inorganic particle B is obtained; S2.

2. The hydrophobic polymer is added to the solvent, and the clean inorganic particle B is added thereto. After stirring, drying, and heat treatment, superhydrophobic modified particles are obtained.

9. According to the preparation method described in claim 8, It is characterized in that The inorganic particle B is selected from one or a combination of quartz sand, garnet, and zeolite; The particle size of the inorganic particle B is 20 - 80 mesh, preferably 40 - 80 mesh.

10. According to the preparation method described in claim 9, It is characterized in that The hydrophobic polymer is selected from one of polytetrafluoroethylene, polyvinylidene fluoride, and polypropylene; The mass concentration of the hydrophobic polymer solution is 20 - 40 wt%; The solvent is one of water and N,N - dimethylformamide; The mass ratio of the clean inorganic particle B to the hydrophobic polymer solution is 1:8 - 20, preferably 1:10 - 15.

11. A filter bed device for treating oil - water emulsion, It is characterized in that It includes a filter column filled with the oil - water emulsion treatment particles prepared according to claims 1 - 3 or according to the preparation method described in claims 4 - 10; Preferably, the filling height of the filter column is greater than or equal to 5 cm, preferably greater than or equal to 10 cm.

12. The application of the oil - water emulsion treatment particles according to claims 1 - 3, It is characterized in that The particles can be used as a filter layer for separating the oil - water emulsion.

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