Superhydrophobic-superoleophobic particles and methods of making the same

Abstract

The present application relates to a kind of super-hydrophobic-super-oleophobic particles and its preparation method, the particle includes particle core material, hydrophobic oleophobic film wrapped in the surface of particle core material and the micro-nano secondary rough structure existing on the surface of hydrophobic oleophobic film;The hydrophobic oleophobic film material includes hydrophobic oleophobic material and film-forming aid, the hydrophobic oleophobic material includes perfluorosilane and silane coupling agent, the micro-nano secondary rough structure material includes micron grade particle material and nanometer grade particle material;The method includes preparing super-hydrophobic-super-oleophobic dispersion and preparing super-hydrophobic-super-oleophobic particle.Compared with prior art, the particle material prepared in the present application simultaneously realizes good hydrophobicity and oleophobicity, and has good durability, production process is simple, compared with traditional super-hydrophobic particle material has significant advantage.

Description

Technical Field

[0001] This invention belongs to the field of dual hydrophobic coating technology, and relates to a superhydrophobic-superoleophobic particle and its preparation method. Background Technology

[0002] In the garment and textile industry, fabrics with waterproof and oil-repellent properties can make clothing self-cleaning, less prone to stain adhesion, significantly reducing washing frequency, effectively reducing water and electricity consumption, saving resources and protecting the environment. In the metal protection industry, effectively mitigating metal corrosion is of great significance. Coating the metal surface with a hydrophobic and oleophobic coating can effectively prevent corrosive media from damaging the metal substrate and resist microbial erosion of the metal, showing significant advantages over traditional coatings. In the field of oil-water separation, superwetting materials can efficiently treat oily wastewater, solving environmental pollution problems caused by oil leaks, industrial oily wastewater, and domestic oily sewage discharge. Patent CN115181443A discloses a superhydrophobic and superoleophobic antibacterial and anticorrosive coating, its preparation method, and its application, using the sol-gel method and spraying method to apply superhydrophobic and superoleophobic SiO2@POS / N + Antibacterial and anti-corrosion coatings are applied to metal surfaces to achieve metal protection, but these coatings often lack adhesion and require adhesive application. Therefore, superwetting materials have broad application prospects in many fields. While there is considerable research on superhydrophobic-superoleophobic materials, these materials require even lower surface energy and micro / nano-rough structures, making them more difficult to obtain. Therefore, developing stable superhydrophobic-superoleophobic particulate materials remains a challenge in current technology.

[0003] Patent CN113842676A discloses a superhydrophilic-superoleophobic particle for oily wastewater treatment, its preparation method, and its application. This superhydrophilic-superoleophobic particle comprises a particle core material, a hydrophilic-oleophobic membrane coating the surface of the particle core material, and a micro-nano secondary roughness structure on the membrane surface. The hydrophilic-oleophobic membrane is obtained by coating the particle material surface with a superhydrophilic-superoleophobic dispersion and then drying and curing it. The micro-nano secondary roughness structure is obtained by adding micron-sized and nano-sized particles sequentially before the coating liquid coating the particle core material surface dries and cures, and then allowing them to adhere to the particle core material surface after drying. This particle is used for oil-water separation. However, the membrane layer of this patent is not stable and durable enough, and can only be used for filtering light oil and water.

[0004] Patent CN115231853A discloses superhydrophobic particles for seepage prevention in artificial lakes, their preparation method, and applications. The method includes the following steps: mixing a particle core material, a hydrophobic resin, and a curing agent until homogeneous; adding a micron-sized hydrophobic material before the hydrophobic resin cures, and then mixing until homogeneous; adding a nano-sized hydrophobic material dispersion, and then mixing until homogeneous; and finally drying to obtain the superhydrophobic particles for seepage prevention in artificial lakes. However, the hydrophobic and oleophilic properties of this patent make it prone to adhering to oil and impurities, leading to a loss of function.

[0005] Patent CN111019482A discloses the preparation and application of a superhydrophobic / oleophobic coating with excellent properties, comprising: dispersing nanoparticles and cellulose in an alcohol solution containing an alkaline substance, adding tetraethyl orthosilicate and a fluorinated organosilane for hydrolysis and coating, forming solution A; dispersing epoxy resin in the alcohol solution, forming solution B; mixing solution A and solution B uniformly, then adding tetraethyl orthosilicate and a fluorinated organosilane for reaction to generate polysiloxane, referred to as solution C; dissolving a fluorinated amine compound in the alcohol solution, referred to as solution D; mixing solution C and solution D uniformly, spraying onto a substrate, and curing, thus obtaining the coating. However, this patent preparation uses multiple chemical reagents, making the preparation process cumbersome.

[0006] Patent CN114015350A discloses a self-cleaning, anti-fouling, superhydrophobic-superoleophobic film material with adjustable wettability and its preparation method, relating to the field of superwetting film technology. The method involves adding micron- or nano-sized solid particles to an organic solvent to obtain a mixed solution, then adding a low surface energy modifier to obtain a white suspension; obtaining solid particles G from the white suspension; obtaining a coating solution L; coating a substrate with the coating solution L and drying it to solidify the film, thus obtaining a superhydrophobic-superoleophobic film. However, this patent's coating process requires multiple modifications and adjustments, making the process relatively complex. Summary of the Invention

[0007] The purpose of this invention is to overcome at least one defect of the prior art and provide a superhydrophobic-superoleophobic particle and its preparation method. The particle material prepared by this invention achieves both good hydrophobicity and oleophobicity, and has good durability. The production process is simple and has significant advantages over traditional superhydrophobic particle materials.

[0008] The objective of this invention can be achieved through the following technical solutions: One of the technical solutions of the present invention is to provide a superhydrophobic-superoleophobic particle, the particle comprising a particle core material, a hydrophobic and oleophobic film wrapped on the surface of the particle core material, and a micro-nano secondary roughness structure on the surface of the hydrophobic and oleophobic film. The hydrophobic and oleophobic film material includes hydrophobic and oleophobic materials and film-forming aids. The hydrophobic and oleophobic materials include perfluorosilanes and silane coupling agents. The micro-nano secondary rough structure material includes micron-sized particle materials and nano-sized particle materials. The particles comprise the following components by weight: 100-300 parts of particle core material, 0.01-0.10 parts of film-forming aid, 1-5 parts of micron-sized particle material and 1-5 parts of nano-sized particle material. The ratio of the hydrophobic and oleophobic material to the film-forming aid is (2-4 mL):(0.01-0.10 g), and the volume ratio of the perfluorosilane to the silane coupling agent is 1:(1-2).

[0009] Furthermore, the granular core material is a granular material selected from one or more of quartz sand, desert sand, river sand, sea sand, tailings sand and manufactured sand, with a particle size of 0.1-0.6 mm.

[0010] Furthermore, the perfluorosilane is selected from one or more of 1H,1H,2H,2H-perfluorodecyltriethoxysilane, 1H,1H,2H,2H-perfluorooctyltriethoxysilane, 1H,1H,2H,2H-perfluorodecyltrimethoxysilane, and 1H,1H,2H,2H-perfluorodecyltrichlorosilane, and the silane coupling agent is selected from one or more of 3-aminopropyltriethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, and vinyltris(β-methoxyethoxy)silane.

[0011] Furthermore, the film-forming aid is selected from one or more of propylene glycol butyl ether, ethylene glycol, propylene glycol, and polyvinylpyrrolidone.

[0012] Furthermore, the micron-sized particulate material is selected from one or more of organosilicon hydrophobic powder, micron-sized activated carbon, and polytetrafluoroethylene micro powder, with a particle size of 1-100 µm.

[0013] Furthermore, the nanoscale particle material is selected from one or more of hydrophobic nano-silica (SiO2), titanium dioxide (TiO2), zinc oxide (ZnO), and silicon carbide (SiC), with a particle size of 5-100 nm.

[0014] One of the technical solutions of the present invention is to provide a method for preparing superhydrophobic-superoleophobic particles, the method comprising the following steps: (1) Preparation of superhydrophobic-superoleophobic dispersion: Add silane coupling agent to solvent and stir magnetically, add perfluorosilane to suspension and stir magnetically, add film-forming aid to obtain superhydrophobic-superoleophobic dispersion; (2) Preparation of superhydrophobic-superoleophobic particles: The superhydrophobic-superoleophobic dispersion is added to the particle core material, and micron-sized particles and nano-sized particles are added in sequence. The mixture is stirred until it is completely dispersed and then dried to obtain superhydrophobic-superoleophobic particles.

[0015] As a preferred technical solution, the granular core material is pretreated by means of the following steps: sieving, washing, and drying the granular core material before use.

[0016] As a preferred technical solution, the preparation of the dispersion in step (1) is carried out at room temperature.

[0017] Further, in step (1), the solvent includes ethanol or acetone, and the volume ratio of silane coupling agent to solvent is 1:(10-40).

[0018] Furthermore, in step (1), the stirring time for the silane coupling agent is 1-2 h, and the stirring time for the perfluorosilane is 3-5 h.

[0019] Furthermore, in step (2), the stirring time for micron-sized and nano-sized particles is 1-2 h, the drying temperature is 55-60 ℃, and the time is 12-24 h.

[0020] One of the technical solutions of the present invention is to provide an application of superhydrophobic-superoleophobic particles, wherein the particles are used for oil-water separation in the treatment of oily wastewater.

[0021] Compared with the prior art, the present invention has the following advantages: (1) The superhydrophobic-superoleophobic particulate material prepared by the present invention has stable superhydrophobicity and superoleophobicity. The particle matrix material can flexibly adjust the particle size and gradation, and has good durability. It has significant advantages over traditional superhydrophobic materials. (2) The superhydrophobic-superoleophobic particulate material prepared by the present invention has the advantages of simple and fast preparation process, large-scale production, convenient reusability and flexible application scenarios, and has broad application prospects. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the Wenzel model of superhydrophobic-superoleophobic particles in an embodiment of the present invention; Figure 2 This is a schematic diagram of the Cassie model of superhydrophobic-superoleophobic particles in an embodiment of the present invention; Figure 3 This is a schematic diagram of the hydrophobic and oleophobic model of superhydrophobic-superoleophobic particles in an embodiment of the present invention. Detailed Implementation

[0023] The present invention will now be described in detail with reference to specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0024] Unless otherwise specified, the equipment used in the following embodiments is conventional equipment in the art; unless otherwise specified, the reagents used are commercially available products or prepared by conventional methods in the art. In the following embodiments, unless otherwise described in detail, conventional experimental methods in the art can be used.

[0025] The concept of this embodiment is to first coat the surface of the particulate core material with a hydrophobic and oleophobic material film. The silane coupling agent's silanoxy groups are reactive to inorganic substances, and its organic functional groups are reactive to organic substances; therefore, it can connect the particulate core material and the perfluorosilane, forming a bonded layer of inorganic matrix particulate core material - silane coupling agent - perfluorosilane. Then, micro / nano-scale particulate materials are introduced to create a micro / nano-rough structure on the surface of the hydrophobic and oleophobic film. For example... Figure 1 As shown, according to the Wenzel hydrophobic model, increasing the surface roughness of particles will improve both surface hydrophobicity and oleophobicity; for example... Figure 2 As shown, according to the Cassie hydrophobic model, the micro-nano rough structure on the particle surface traps an air film, reducing the contact area between the particle surface and the liquid on the contact surface, thus further improving the hydrophobicity and oleophobicity of the particles. Figure 3 As shown, when water or oil enters the inter-particle spaces, because the particles are superhydrophobic and superoleophobic materials, the contact angles of water and oil are both greater than 150°, resulting in an upward additional pressure on the water or oil. The larger the contact angle, the greater the additional pressure. When the additional pressure exceeds the pressure generated by the liquid's gravity, the liquid cannot penetrate the inter-particle spaces. Silane coupling agents build "molecular bridges" between the interfaces of inorganic and organic substances, connecting two materials with vastly different properties. This allows the organic film layer to adhere to the surface of the core material particles, forming a dense film layer that enables stable superhydrophobic and superoleophobic properties on the surface.

[0026] Example 1: A superhydrophobic-superoleophobic particle and its preparation method, the specific steps of which are as follows: 1 mL of 3-aminopropyltriethoxysilane (APS) was added to 20 mL of anhydrous ethanol and magnetically stirred for 1 h. Then, 1 mL of 1H,1H,2H,2H-perfluorodecyltriethoxysilane was added to the suspension and magnetically stirred for 3 h. 0.05 g of propylene glycol was then added to obtain a superhydrophobic-superoleophobic dispersion. 200 g of quartz sand, sieved to 0.3 mm and washed and dried, was poured into a mixing vessel. The superhydrophobic-superoleophobic dispersion was then poured into the quartz sand, and while stirring, 1.0 g of 35 μm activated carbon and 1.0 g of 12 nm hydrophobic nano-silica (SiO2) were added sequentially. The mixture was stirred for 1 h until completely dispersed. The stirred sample was placed in a drying oven and dried at 55 ℃ for 24 h to obtain superhydrophobic-superoleophobic particulate material.

[0027] Example 2: A superhydrophobic-superoleophobic particle and its preparation method, the specific steps of which are as follows: 2 mL of 3-aminopropyltriethoxysilane was added to 40 mL of anhydrous ethanol and magnetically stirred for 1 h. Then, 2 mL of 1H,1H,2H,2H-perfluorooctyltriethoxysilane was added to the suspension and magnetically stirred for 3 h. 0.10 g of propylene glycol butyl ether was then added to obtain a superhydrophobic-superolephobic dispersion. 300 g of desert sand, sieved to 0.3 mm and washed and dried, was poured into a mixing vessel. The superhydrophobic-superolephobic dispersion was then poured into the desert sand, and while stirring, 3.0 g of 50 μm hydrophobic organosilicon powder and 3.0 g of 25 nm hydrophobic nano-titanium dioxide (TiO2) were added sequentially. The mixture was stirred for 1.5 h until completely dispersed. The stirred sample was placed in a drying oven and dried at 60 ℃ for 24 h to obtain superhydrophobic-superolephobic particulate material.

[0028] Example 3: A superhydrophobic-superoleophobic particle and its preparation method, the specific steps of which are as follows: 1 mL of 3-aminopropyltriethoxysilane was added to 20 mL of acetone and magnetically stirred for 1 h. Then, 1 mL of 1H,1H,2H,2H-perfluorodecyltrimethoxysilane was added to the suspension and magnetically stirred for 3 h. 0.10 g of polyvinylpyrrolidone was then added to obtain a superhydrophobic-superoleophobic dispersion. 200 g of sea sand, sieved to 0.3 mm and washed and dried, was poured into a mixing vessel. The superhydrophobic-superoleophobic dispersion was then poured into the sea sand, and while stirring, 2.0 g of 35 μm polytetrafluoroethylene powder and 2.0 g of 12 nm hydrophobic nano-silica were added sequentially. The mixture was stirred for 2 h until completely dispersed. The stirred sample was placed in a drying oven and dried at 60 ℃ for 24 h to obtain superhydrophobic-superoleophobic particulate material.

[0029] The water contact angle and oil contact angle of the superhydrophobic-superoleophobic particles prepared in Examples 1 to 3 were tested respectively, and the results are shown in Table 1.

[0030] Table 1 Contact Angle Test of Superhydrophobic-Superoleophobic Particles As shown in Table 1, the water contact angle and various oil contact angles of the superhydrophobic-superoleophobic particles prepared in this embodiment are all greater than 150°, exhibiting good hydrophobicity and oleophobicity.

[0031] The superhydrophobic-superoleophobic particles prepared in Examples 1 to 3 were subjected to water pressure resistance and oil pressure resistance tests, as shown in Table 2.

[0032] Table 2 Hydraulic Resistance Test of Superhydrophobic-Superoleophobic Particles As shown in Table 2, the superhydrophobic-superoleophobic particles prepared in this embodiment can withstand the pressure generated by a water column of about 2.4 m in height without leakage, and can withstand the pressure generated by a soybean oil column of about 1.2 m in height without leakage. This is a specific manifestation of the hydrophobic and oleophobic properties of the particles.

[0033] The superhydrophobic-superoleophobic particles prepared in Examples 1 to 3 were subjected to oil-water separation tests under a pressure of 500 Pa, as shown in Table 3.

[0034] Table 3. Oil-water separation efficiency test of superhydrophobic-superoleophobic particles As shown in Table 3, the superhydrophobic-superoleophobic particles prepared in this embodiment for oily wastewater treatment have an efficiency of over 99% for water separation of various oil-water mixtures, demonstrating excellent oil-water separation performance. Furthermore, the particles do not adhere to water or oil stains on their surface, allowing for direct oil-water separation and convenient reuse.

[0035] After the superhydrophobic-superoleophobic particles prepared in Examples 1 to 3 were reused 30 times, the oil-water mixtures were subjected to oil-water separation tests under pressure, as shown in Table 4.

[0036] Table 4. Oil-water separation efficiency and durability test of superhydrophobic-superoleophobic particles after repeated use As shown in Table 4, the superhydrophobic-superoleophobic particles prepared in this embodiment for oily wastewater treatment have almost no change in separation efficiency after being reused 30 times, demonstrating good durability.

[0037] To test the stability of the product in air, the superhydrophobic-superoleophobic particles prepared in Examples 1 to 3 were placed under natural conditions for 6 months, and the above-mentioned indicators were re-measured. The measurement results are shown in Tables 5 to 7.

[0038] Table 5. Contact angle durability test of superhydrophobic-superoleophobic particles after natural placement. Table 6. Hydraulic durability test of superhydrophobic-superoleophobic particles after natural placement. Table 7. Oil-water separation efficiency and durability test of superhydrophobic-superoleophobic particles after natural placement. As shown in Tables 5 to 7, the superhydrophobic-superoleophobic particles prepared in this embodiment still have a water contact angle and various oil contact angles greater than 150° after being placed under natural conditions for 6 months, and the oil-water separation efficiency is only slightly reduced, demonstrating good durability.

[0039] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A superhydrophobic-superoleophobic particle, characterized in that, The particles are used for oil-water separation in oily wastewater treatment. The particles include a particle core material, a hydrophobic and oleophobic film wrapped around the surface of the particle core material, and a micro-nano secondary rough structure on the surface of the hydrophobic and oleophobic film. The hydrophobic and oleophobic film material includes hydrophobic and oleophobic materials and film-forming aids. The hydrophobic and oleophobic materials include perfluorosilanes and silane coupling agents. The micro-nano secondary rough structure material includes micron-sized particle materials and nano-sized particle materials. The superhydrophobic-superoleophobic particles comprise the following components by weight: 100-300 parts of particle core material, 0.01-0.10 parts of film-forming aid, 1-5 parts of micron-sized particle material, and 1-5 parts of nano-sized particle material. The ratio of the hydrophobic and oleophobic material to the film-forming aid is (2-4 mL):(0.01-0.10 g), and the volume ratio of the perfluorosilane to the silane coupling agent is 1:(1-2). The perfluorosilane is selected from one or more of 1H,1H,2H,2H-perfluorodecyltriethoxysilane, 1H,1H,2H,2H-perfluorooctyltriethoxysilane, 1H,1H,2H,2H-perfluorodecyltrimethoxysilane, and 1H,1H,2H,2H-perfluorodecyltrichlorosilane; the silane coupling agent is selected from one or more of 3-aminopropyltriethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, and vinyltris(β-methoxyethoxy)silane. The film-forming aid is selected from one or more of propylene glycol butyl ether, ethylene glycol, propylene glycol, and polyvinylpyrrolidone; The micron-sized particulate material is selected from one or more of organosilicon hydrophobic powder, micron-sized activated carbon and polytetrafluoroethylene powder, with a particle size of 1-100 µm; The nanoscale particulate material is selected from one or more of hydrophobic nano-silica, titanium dioxide, zinc oxide and silicon carbide, with a particle size of 5-100 nm; The method for preparing the superhydrophobic-superoleophobic particles includes the following steps: (1) Preparation of superhydrophobic-superoleophobic dispersion: Add silane coupling agent to solvent and stir, add perfluorosilane to mixture and stir, add film-forming aid to obtain superhydrophobic-superoleophobic dispersion; (2) Preparation of superhydrophobic-superoleophobic particles: The superhydrophobic-superoleophobic dispersion is added to the particle core material, and then micron-sized particles and nano-sized particles are added in sequence. The mixture is stirred until it is completely dispersed and dried to obtain superhydrophobic-superoleophobic particles. In step (1), the solvent includes ethanol or acetone, and the volume ratio of silane coupling agent to solvent is 1:(10-40); In step (1), the stirring time for silane coupling agent is 1-2 h, and the stirring time for perfluorosilane is 3-5 h; In step (2), the stirring time for micron-sized and nano-sized particles is 1-2 h, the drying temperature is 55-60℃, and the time is 12-24 h.

2. The superhydrophobic-superoleophobic particle according to claim 1, characterized in that, The granular core material is a granular material with a particle size of 0.1-0.6 mm.

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