A visible light-responsive oil-water separation membrane material and its preparation method

Abstract

This invention provides an oil-water separation membrane material with visible light response and its preparation method. The preparation method includes the following steps: removing iron oxide from the surface of a stainless steel mesh, mixing it with an etched cotton fiber substrate membrane and a mixed solution of tetrabutyl titanate-hydrochloric acid aqueous solution, and performing a hydrothermal reaction to obtain the oil-water separation membrane material. Compared with the prior art, the preparation method provided by this invention adopts a one-step hydrothermal synthesis method. Under high temperature and pressure, titanium dioxide microspheres are slowly loaded onto the cotton fiber substrate membrane using a titanium-based material precursor to prepare a titanium-based membrane material with a cotton fiber membrane substrate. Using a stainless steel mesh as a reaction raw material can greatly enhance the superhydrophobicity and oleophilicity of the membrane. Simultaneously, the titanium-based membrane material prepared by this method possesses both oil-water separation performance and photoresponsiveness.

Description

Technical Field

[0001] This invention relates to the field of oil-water separation technology, and more specifically, to an oil-water separation membrane material with visible light response and its preparation method. Background Technology

[0002] Highly efficient oil-water separation technology, especially self-cleaning oil-water mixture separation membrane technology, is widely used to alleviate water pollution problems. In recent years, membrane materials with photoresponsiveness, self-cleaning properties, and special wetting properties have been widely used in the treatment of oily wastewater. Therefore, we need to separate oil-water mixtures and oil-water emulsions. However, at present, surface-adaptive materials capable of oil-water separation still face significant challenges. Due to the pollution problems of oils and the use of organic solvents and fluorinated reagents that are toxic to humans and harmful to the environment, some oil-water separation membrane materials are difficult to apply in practice. Therefore, novel surface-adaptive or oleophilic membrane materials with stable hydrophobicity, recyclability, and durable oil and water resistance show potential applications in industrial and daily life for oil-water separation.

[0003] Titanium dioxide is an inorganic semiconductor material. When titanium dioxide is irradiated with ultraviolet light, electrons in the valence band are excited to the conduction band, resulting in a lack of electrons in the valence band and the formation of holes. These holes create highly mobile and reactive electron-hole pairs, thus exhibiting excellent ultraviolet light absorption characteristics, ease of preparation, and non-toxicity. It typically possesses excellent photothermal stability and light absorption rate, making it a highly promising potential photocatalytic material. Inspired by photocatalytic degradation of pollutants and oil-water separation technologies, various methods have been proposed both domestically and internationally to prepare superhydrophilic and superoleophobic titanium-based membrane materials for the photodegradation of water pollution. Commonly used substrate materials include PDMS, cotton fibers, and titanium mesh.

[0004] Currently, most existing methods use organic or metal substrates for membrane materials. These materials are complex to prepare and require stringent preparation conditions. Most importantly, the materials that can perform photocatalysis are mostly precious metals, which are too expensive and unsuitable for large-scale industrial production. Furthermore, the membrane materials prepared by these methods are mostly superoleophobic and superhydrophilic, resulting in poor oil-water separation. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide an oil-water separation membrane material with visible light response and its preparation method. The preparation method provided by this invention adopts a one-step hydrothermal synthesis method. Under high temperature and high pressure, titanium dioxide microspheres are slowly loaded onto cotton fiber substrate membrane fibers using a titanium-based material precursor to prepare a titanium-based membrane material with a cotton fiber membrane substrate. Using stainless steel mesh as a reaction raw material can greatly enhance the superhydrophobicity and oleophilicity of the membrane. At the same time, the titanium-based membrane material prepared by this method has both oil-water separation performance and photoresponsiveness. In addition, this preparation method has the advantages of simple process and low cost, making it an excellent way to achieve large-scale production.

[0006] This invention provides a method for preparing an oil-water separation membrane material with visible light response, comprising the following steps:

[0007] After removing the iron oxide from the surface of the stainless steel mesh, it is mixed with an etched cotton fiber substrate membrane and a mixed solution of tetrabutyl titanate-hydrochloric acid aqueous solution, and subjected to a hydrothermal reaction to obtain an oil-water separation membrane material.

[0008] Preferably, the stainless steel mesh has a mesh count of 100 to 800.

[0009] Preferably, the process of removing iron oxide from the surface of the stainless steel mesh uses a mixture of ferric chloride and hydrochloric acid.

[0010] The concentration of ferric chloride in the ferric chloride hydrochloric acid mixed solution is 1 mol / L to 2 mol / L.

[0011] Preferably, the method for preparing the etched cotton fiber base film is as follows:

[0012] After cleaning the cotton cloth, it is mixed with sodium hydroxide solution and stirred at 60℃~100℃ and 80r / min~120r / min for 20min~60min to obtain the etched cotton fiber base film.

[0013] Preferably, the concentration of the sodium hydroxide solution is 0.1 mol / ~1 mol / L.

[0014] Preferably, the stirring method is magnetic stirring, mechanical stirring, or vibration.

[0015] Preferably, in the mixed solution of tetrabutyl titanate and hydrochloric acid aqueous solution, the volume ratio of tetrabutyl titanate to hydrochloric acid aqueous solution is (1~2):40;

[0016] The hydrochloric acid aqueous solution is composed of concentrated hydrochloric acid and water in a volume ratio of 1:(2~4).

[0017] Preferably, the ratio of the volume of the stainless steel mesh after removing surface iron oxide, the etched cotton fiber base film, and the mixed solution of tetrabutyl titanate-hydrochloric acid aqueous solution is 0.1g:(1.5g~2g):(41mL~42mL).

[0018] Preferably, the hydrothermal reaction is carried out at a temperature of 150°C to 160°C for 5 to 6 hours.

[0019] The present invention also provides an oil-water separation membrane material with visible light response, which is prepared by the preparation method described in the above technical solution.

[0020] This invention provides an oil-water separation membrane material with visible light response and its preparation method. The preparation method includes the following steps: removing iron oxide from the surface of a stainless steel mesh, mixing it with an etched cotton fiber substrate membrane and a mixed solution of tetrabutyl titanate-hydrochloric acid aqueous solution, and performing a hydrothermal reaction to obtain the oil-water separation membrane material. Compared with the prior art, the preparation method provided by this invention adopts a one-step hydrothermal synthesis method. Under high temperature and pressure, titanium dioxide microspheres are slowly loaded onto cotton fiber membrane fibers using a titanium-based material precursor to prepare a titanium-based membrane material with a cotton fiber substrate membrane. Using a stainless steel mesh as a reaction raw material can greatly enhance the superhydrophobicity and oleophilicity of the membrane. Simultaneously, the titanium-based membrane material prepared by this method possesses both oil-water separation performance and photoresponsiveness.

[0021] In addition, this preparation method has the advantages of simple process and low cost, making it an excellent way to achieve large-scale production. Attached Figure Description

[0022] Figure 1 SEM image of the oil-water separation membrane material prepared by the preparation method provided in the embodiments of the present invention;

[0023] Figure 2 The water contact angle of the oil-water separation membrane material prepared by the preparation method provided in the embodiments of the present invention;

[0024] Figure 3 The diagram shows the oil-water separation efficiency and oil permeation flux of the oil-water separation membrane material prepared by the preparation method provided in the embodiments of the present invention.

[0025] Figure 4 The ultraviolet-visible-near-infrared spectrum of the oil-water separation membrane material prepared by the preparation method provided in the embodiments of the present invention;

[0026] Figure 5 The temperature rise and fall diagrams of the oil-water separation membrane material prepared by the preparation method provided in the embodiments of the present invention after xenon lamp irradiation. Detailed Implementation

[0027] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0028] This invention provides a method for preparing an oil-water separation membrane material with visible light response, comprising the following steps:

[0029] After removing the iron oxide from the surface of the stainless steel mesh, it is mixed with an etched cotton fiber substrate membrane and a mixed solution of tetrabutyl titanate-hydrochloric acid aqueous solution, and subjected to a hydrothermal reaction to obtain an oil-water separation membrane material.

[0030] This invention provides a method for preparing an oil-water separation membrane material with visible light response, specifically involving the preparation of a superhydrophobic Fe / TiO2 membrane. Through the preparation principle and method of ferrous ion doping on TiO2 microparticles loaded with cotton fiber membrane, this Fe / TiO2 membrane material can quickly, safely, and environmentally treat oil pollution in water.

[0031] The present invention first removes iron oxide from the surface of the stainless steel mesh; the present invention does not have any special restrictions on the type and source of the stainless steel mesh, and commercially available products well known to those skilled in the art can be used; in a preferred embodiment of the present invention, the stainless steel mesh is a commercially available 304 stainless steel mesh.

[0032] In this invention, the stainless steel mesh is preferably 100 to 800 mesh, and more preferably 300 to 500 mesh.

[0033] In this invention, the process of removing iron oxide from the surface of the stainless steel mesh preferably uses a mixture of ferric chloride and hydrochloric acid.

[0034] In this invention, the concentration of ferric chloride in the ferric chloride hydrochloric acid mixed solution is preferably 1 mol / L to 2 mol / L, more preferably 1.5 mol / L.

[0035] In this invention, the preferred method for preparing the etched cotton fiber base film is as follows:

[0036] After washing the cotton cloth, it was mixed with sodium hydroxide solution and stirred at 60℃~100℃ and 80r / min~120r / min for 20min~60min to obtain the etched cotton fiber base film.

[0037] More preferably:

[0038] After washing the cotton cloth, it was mixed with sodium hydroxide solution and stirred at 70℃~90℃ and 90r / min~110r / min for 30min~50min to obtain the etched cotton fiber base film.

[0039] The present invention does not impose any special restrictions on the cleaning process, and any cleaning solution using deionized water and / or anhydrous ethanol that is well known to those skilled in the art can be used.

[0040] In this invention, the concentration of the sodium hydroxide solution is preferably 0.1 mol / L to 1 mol / L, more preferably 0.4 mol / L to 0.6 mol / L.

[0041] In this invention, the stirring method is preferably magnetic stirring, mechanical stirring, or vibration.

[0042] In this invention, the volume ratio of tetrabutyl titanate to aqueous hydrochloric acid in the mixed solution is preferably (1~2):40, more preferably 1.5:40.

[0043] In this invention, the hydrochloric acid aqueous solution is preferably composed of concentrated hydrochloric acid and water in a volume ratio of 1:(2~4), more preferably 1:3; wherein the concentration of the concentrated hydrochloric acid is preferably 36wt%~38wt%.

[0044] In this invention, the tetrabutyl titanate is a precursor for forming titanium dioxide particles, and there are no special restrictions on its source.

[0045] In this invention, the preferred ratio of the amount of the stainless steel mesh after removing surface iron oxide, the etched cotton fiber base film, and the mixed solution of tetrabutyl titanate-hydrochloric acid aqueous solution is 0.1g:(1.5g~2g):(41mL~42mL), and more preferably 0.1g:1.5g:41.5mL.

[0046] In this invention, the hydrothermal reaction can be carried out using a hydrothermal reactor well known to those skilled in the art; the preferred temperature of the hydrothermal reaction is 150℃~160℃, and the preferred time is 5h~6h; based on this, during the process of obtaining the photothermal oil-water separation membrane material, a superhydrophobic micro-nano structure appears on the surface.

[0047] This invention uses ferrous ions as the main doping ions to alter the morphology of titanium dioxide microspheres under high temperature and pressure. Microscopically, this gives the film the theoretical support of the Cassie-Baxter equation, and macroscopically, it gives the film superhydrophobic properties with low surface energy. This allows for the treatment of oily wastewater through oil-water separation. At the same time, the preparation method provided by this invention has the advantages of simple process and low cost, making it an excellent way to achieve large-scale production.

[0048] This invention also provides an oil-water separation membrane material with visible light response, prepared using the method described in the above technical solution. In this invention, the oil-water separation membrane material is a Fe / TiO2 cotton fiber titanium-based oil-water separation membrane with photothermal properties, possessing both oil-water separation performance and photoresponsiveness.

[0049] This invention utilizes titanium dioxide as the raw material for membrane materials and adds stainless steel mesh as element ion doping. The resulting titanium-based membrane material is more suitable for industrial applications and has great application potential in the preparation of superhydrophobic materials.

[0050] This invention provides an oil-water separation membrane material with visible light response and its preparation method. The preparation method includes the following steps: removing iron oxide from the surface of a stainless steel mesh, mixing it with an etched cotton fiber substrate membrane and a mixed solution of tetrabutyl titanate-hydrochloric acid aqueous solution, and performing a hydrothermal reaction to obtain the oil-water separation membrane material. Compared with the prior art, the preparation method provided by this invention adopts a one-step hydrothermal synthesis method. Under high temperature and pressure, titanium dioxide microspheres are slowly loaded onto the cotton fiber substrate membrane using a titanium-based material precursor to prepare a titanium-based membrane material with a cotton fiber membrane substrate. Using a stainless steel mesh as a reaction raw material can greatly enhance the superhydrophobicity and oleophilicity of the membrane. Simultaneously, the titanium-based membrane material prepared by this method possesses both oil-water separation performance and photoresponsiveness.

[0051] In addition, this preparation method has the advantages of simple process and low cost, making it an excellent way to achieve large-scale production.

[0052] To further illustrate the present invention, the following embodiments will be described in detail.

[0053] Example

[0054] (1) Prepare a mixed solution containing tetrabutyl titanate (1.5 mL, liquid) and hydrochloric acid aqueous solution (40 mL, of which the concentration of concentrated hydrochloric acid: H2O = 10 mL: 30 mL with a concentration of 36 wt%~38 wt%), and a mixed solution of sodium hydroxide solution with a concentration of 0.5 mol / L and ferric chloride hydrochloric acid (50 mL, of which the concentration of ferric chloride is 1.5 mol / L).

[0055] The preparation method of the mixed solution of tetrabutyl titanate and hydrochloric acid aqueous solution is as follows:

[0056] Pour 1.5 mL of tetrabutyl titanate liquid into the hydrochloric acid aqueous solution and mix well;

[0057] The method for preparing sodium hydroxide solution is as follows:

[0058] Dissolve sodium hydroxide in water;

[0059] The method for preparing a ferric chloride-hydrochloric acid mixed solution is as follows:

[0060] 30% ferric chloride was dispersed in an aqueous hydrochloric acid solution.

[0061] (2) Mix 0.5g of 304 stainless steel mesh (400 mesh) with the ferric chloride hydrochloric acid mixture solution in step (1) to remove the iron oxide on the surface of the stainless steel mesh.

[0062] (3) After washing 0.1g of cotton cloth with a radius of 2cm with deionized water and anhydrous ethanol, it is mixed with sodium hydroxide solution in step (1) and stirred at 80℃ and 100r / min for 40min to obtain the etched cotton fiber base film.

[0063] (4) The etched cotton fiber substrate membrane obtained in step (3), the mixed solution of tetrabutyl titanate and hydrochloric acid aqueous solution in step (1), and the stainless steel mesh obtained in step (2) are poured into a hydrothermal reactor (inner 100mL). Under acidic conditions, the stainless steel mesh with iron oxide removed is reacted continuously at 155℃ for 5.5h to obtain Fe / TiO2 cotton fiber titanium substrate membrane photothermal oil-water separation membrane material.

[0064] The properties of the oil-water separation membrane material prepared by the preparation method provided in the embodiments of the present invention were tested:

[0065] (1) SEM image (generally considered as a magnified image at a very high magnification) See Figure 1 As shown; the SEM image of the Fe / TiO2 film shows that the fine particles are... Figure 1 The series shown is loaded on fibers. Figure 1 The structure on the cotton fibers was magnified to obtain the "petal-shaped" structure with hydrophobic structure shown in the figure; the microsphere particles formed a cauliflower-shaped micro-nano structure. Therefore, it can be inferred that the Fe / TiO2 membrane has good hydrophobicity and oil-water separation effect.

[0066] (2) Water contact angle such as Figure 2 As shown, in air, water droplets form a hydrophobic angle of 153.37° on the membrane surface, proving that the membrane has excellent superhydrophobicity.

[0067] Water contact angle (θ): To reflect the hydrophobic properties of a material, it is generally considered that:

[0068] 0°≤θ<10°, superhydrophilic

[0069] 10°≤θ<90°, hydrophilic.

[0070] 90°≤θ<150°, hydrophobic.

[0071] 150°≤θ, superhydrophobic.

[0072] (3) See the diagrams for oil-water separation efficiency and oil permeation flux. Figure 3 As shown;

[0073] Continuous oil-water separation efficiency ( The calculation formula for ) is as follows:

[0074] ;

[0075] Where m0(g) represents the initial mass of oil before oil-water separation, and m1(g) represents the weight of oil after separation;

[0076] The formula for calculating the oil permeation flux (J) in continuous oil-water separation is as follows:

[0077] ;

[0078] Among them, J(L·m -2 ·h -1 V(L) represents the permeation flux of oil in oil-water separation, and A(m³) represents the volume of separated oil. 2 ) represents the separation area of ​​the oil-water separation membrane, and ΔT(h) represents the time required for the oil-water separation experiment.

[0079] (4) See the ultraviolet-visible-near-infrared spectrum. Figure 4 As shown; the absorption capacity curve of the membrane under light with wavelengths of 250nm~800nm, the closer it is to 1, the stronger the absorption capacity;

[0080] Ultraviolet-visible-near-infrared spectroscopy: By emitting light with wavelengths from 250 nm to 800 nm and measuring the light absorption rate of the Fe / TiO2 film, it is determined whether the film has good light absorption capacity. The closer the light absorption rate is to 1, the stronger the light absorption capacity.

[0081] (5) See the temperature rise and fall graph after irradiation by a xenon lamp (a light source device that can be used to simulate natural light). Figure 5 As shown, under a fixed illumination intensity of a xenon lamp, the xenon lamp is turned on, and the surface temperature of the film is observed using a thermal imager. After a certain period of time, the xenon lamp is turned off, and the temperature rise and fall curves of the film surface are obtained.

[0082] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing an oil-water separation membrane material with visible light response, comprising the following steps: removing iron oxide on the surface of a stainless steel mesh, mixing the stainless steel mesh with a mixed solution of an etched cotton fiber base membrane and a tetrabutyl titanate-hydrochloric acid aqueous solution, and performing a hydrothermal reaction to obtain the oil-water separation membrane material; the method for preparing the etched cotton fiber base membrane comprises the following steps: washing cotton cloth, mixing the cotton cloth with a sodium hydroxide solution, and obtaining the etched cotton fiber base membrane; in the mixed solution of the tetrabutyl titanate-hydrochloric acid aqueous solution, the volume ratio of the tetrabutyl titanate to the hydrochloric acid aqueous solution is (1.5-2):40; the dosage ratio of the removed stainless steel mesh, the etched cotton fiber membrane, and the mixed solution of the tetrabutyl titanate-hydrochloric acid aqueous solution is 0.1 g:(1.5 g-2 g):(40 mL-42 mL); the hydrochloric acid aqueous solution is composed of concentrated hydrochloric acid and water with a volume ratio of 1:(2-4); the temperature of the hydrothermal reaction is 150-160 °C.

2. The production method according to claim 1, characterized by, the mesh number of the stainless steel mesh is 100-800; 3. The preparation method according to claim 1, characterized in that, the process of removing iron oxide on the surface of the stainless steel mesh uses a mixed solution of ferric chloride and hydrochloric acid; the concentration of ferric chloride in the mixed solution of ferric chloride and hydrochloric acid is 1-2 mol / L.

4. The method of claim 1, wherein, the method for preparing the etched cotton fiber base membrane comprises the following steps: washing cotton cloth, mixing the cotton cloth with a sodium hydroxide solution, stirring at 60-100 °C and 80-120 r / min for 20-60 min, and obtaining the etched cotton fiber base membrane.

5. The preparation method according to claim 4, characterized in that, the concentration of the sodium hydroxide solution is 0.1-1 mol / L.

6. The preparation method according to claim 4, characterized in that, the stirring mode is magnetic stirring, mechanical stirring, or oscillation.

7. The preparation method according to claim 1, characterized in that, the time of the hydrothermal reaction is 5-6 h.

8. An oil-water separation membrane material with visible light response, characterized in that, the oil-water separation membrane material is prepared by the method of any one of claims 1-7.

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