CN119368007A

CN119368007A - A preparation method and application of oil-water separation membrane

Info

Publication number: CN119368007A
Application number: CN202411325103.5A
Authority: CN
Inventors: 刘松; 李萱; 万慧雄
Original assignee: Anhui Huitong New Energy Technology Co ltd; Orinko Advanced Plastics Co Ltd
Current assignee: Anhui Huitong New Energy Technology Co ltd; Orinko Advanced Plastics Co Ltd
Priority date: 2024-09-23
Filing date: 2024-09-23
Publication date: 2025-01-28

Abstract

The invention discloses a preparation method and application of an oil-water separation film, and belongs to the technical field of oil-water separation, comprising the following steps of 1, performing hydrolytic annealing treatment on tetrabutyl titanate to obtain titanium dioxide nano particles with hydroxyl-enriched surfaces; and step 3, the silanized titanium dioxide nano particles are subjected to ultrasonic dispersion in a mixed solvent for 10 min to obtain a homogeneous precursor solution, then polylactic acid is added, stirring and dispersion are carried out to obtain a spinning solution, and the spinning solution is subjected to electrostatic spinning to obtain the oil-water separation film. In addition, the oil-water separation membrane can effectively purify oily wastewater, can be naturally degraded after the service life is finished, and reduces the negative influence on the environment to the greatest extent.

Description

Preparation method and application of oil-water separation film

Technical Field

The invention belongs to the technical field of oil-water separation, and particularly relates to a preparation method and application of an oil-water separation film.

Background

Offshore crude oil leakage and industrial oily waste water discharge pose serious threats to the ecosystem and human health, while severely damaging the global water-food-energy chain. To address this challenge, super-hydrophilic membrane-based oil-water separation techniques have been widely used to treat oily wastewater. The separation principle of the technology depends on super hydrophilicity of the material, so that water can smoothly pass through a pore structure in the material and form a hydration layer on the surface, thereby effectively preventing oil penetration. In addition, the micropore structure of the material and capillary force generated by high specific surface area can promote the demulsification of the emulsion, and the oil-water separation can be realized.

However, most of the existing oil-water separation membranes are derived from fossil resources, and membrane waste treatment often adopts modes of burying or burning and the like, so that secondary pollution can be caused, and sustainable development of ecological environment is not facilitated. Therefore, it is important to develop an oil-water separation membrane with biodegradable characteristics.

Disclosure of Invention

The invention aims to provide a preparation method and application of an oil-water separation film, and the film overcomes the defects of low filtration efficiency, non-biodegradability and the like of the existing oil-water separation film.

The aim of the invention can be achieved by the following technical scheme:

the preparation method of the oil-water separation film comprises the following steps:

step 1, performing hydrolytic annealing treatment on tetrabutyl titanate to obtain titanium dioxide nano particles with surfaces rich in hydroxyl groups;

Step 2, modifying the titanium dioxide nano-particles rich in hydroxyl groups to obtain silanized titanium dioxide nano-particles;

And 3, ultrasonically dispersing the silanized titanium dioxide nano particles in a mixed solvent for 10min to obtain a homogeneous precursor solution, adding polylactic acid, stirring and dispersing until the precursor solution is transparent to obtain a spinning solution, and carrying out electrostatic spinning on the spinning solution to obtain the oil-water separation film.

Further, the preparation method of the titanium dioxide nano-particles with the surfaces rich in hydroxyl groups comprises the following steps:

Mixing deionized water and tetrabutyl titanate according to the dosage ratio of 1-2g to 1-10mL, stirring and reacting for 2h at a low temperature of 4 ℃, centrifuging and precipitating, and treating for 8h at a temperature of 80-120 ℃ to obtain the titanium dioxide nano particles rich in hydroxyl.

Further, the specific preparation steps of the silanized titanium dioxide nanoparticles are as follows:

Mixing titanium dioxide nano particles rich in hydroxyl, ionized water and a silane coupling agent according to the dosage ratio of 2g to 5mL, placing the mixture in a vacuum closed container, continuously reacting for 2 hours at 100-150 ℃ under vacuum (less than 0.1 Pa), washing the mixture with absolute ethyl alcohol after the reaction is finished, centrifuging, precipitating, and freeze-drying to obtain the silanized titanium dioxide nano particles.

Further, the silane coupling agent is any one or more of methyltrimethoxysilane, vinyltrimethoxysilane, gamma-aminopropyl trimethoxysilane, trimethoxy (propyl) silane, trimethylchlorosilane, tetraethyl orthosilicate and propyl trimethoxysilane.

Further, the mass ratio of the silanized titanium dioxide nano particles to the polylactic acid to the mixed solvent is 0.05-0.3:1-3:10.

Further, the mixed solvent consists of a solvent A and a solvent B according to the mass ratio of 7-10:1.5-4.5, wherein the solvent A is chloroform or methylene dichloride, and the solvent B is any one of dimethylformamide, ethyl acetate and formic acid.

Further, the electrostatic spinning voltage was 15KV, the spinning flow rate was 1.0mL/h, and the spinning distance was 15cm.

Further, the prepared oil-water separation film is applied to the field of oil-water separation.

The invention has the beneficial effects that:

(1) According to the invention, polylactic acid is used as an oil-water separation film substrate, the polylactic acid is mixed with the silanized titanium dioxide nanoparticle solution to form spinning solution, and the oil-water separation film is prepared through an electrostatic spinning process, so that the oil-water separation film can not only effectively purify oily wastewater, but also can be naturally degraded after the service life is finished, and the negative influence on the environment is reduced to the greatest extent. The technology is expected to be widely applied to the fields of oil-containing wastewater treatment, urban sewage treatment, crude oil leakage emergency response, ship transportation, oil gas exploitation and the like generated in petrochemical industry, metallurgy, textile industry, food industry and the like, and contributes to realizing efficient oil-water separation and environmental protection.

(2) According to the method, the uniform and efficient combination of the polylactic acid and the nano particles is realized by introducing the silanized titanium dioxide nano particles, and a multi-stage structure is constructed, so that the prepared oil-water separation film has stable and excellent oil-water separation characteristics.

(3) The silane functional group on the surface of the titanium dioxide nano-particle can improve the interfacial compatibility between polylactic acid and the nano-particle, so that a multistage network structure is formed inside the oil-water separation film, and the prepared oil-water separation film has excellent hydrophobic performance.

(4) The oil-water separation film is prepared by high-efficiency compounding of the silanized titanium dioxide nano particles and polylactic acid and then an electrostatic spinning process. The nano-sized silanized titanium dioxide realizes homogeneous mixing with polylactic acid, and the prepared oil-water separation film has excellent oil-water separation characteristics. In addition, the oil-water separation membrane can effectively purify oily wastewater, can be naturally degraded after the service life is finished, and reduces the negative influence on the environment to the greatest extent.

Drawings

The invention is further described below with reference to the accompanying drawings.

FIG. 1 is a schematic diagram of a finished product of an oil-water separation membrane obtained by the preparation method of example 1 of the present invention;

FIG. 2 is a scanning electron microscope image of an oil-water separation film obtained by the preparation methods of example 1, example 2, example 3 and comparative example 1 of the present invention;

FIG. 3 is an optical photograph showing the hydrophilic contact angle of the oil-water separation film obtained by the preparation method of example 1 and comparative example 1 of the present invention;

FIG. 4 is an optical photograph of the oleophilic contact angle of the oil-water separation film obtained by the preparation method of example 1 and comparative example 1 of the present invention;

FIG. 5 is a graph showing the relationship between the hydrophilic contact angle and time of the oil-water separation films obtained by the preparation methods of example 1 and comparative example 1 of the present invention;

FIG. 6 is a graph showing the relationship between the oleophilic contact angle of the oil-water separation film obtained by the preparation method of example 1 and comparative example 1 of the present invention and time;

FIG. 7 is a schematic view of an oil-water separator of the present invention;

FIG. 8 is a graph showing the oil-water separation flow rate of the oil-water separation film of comparative example 1, example 2 and example 3.

Detailed Description

The technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention, and it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

The preparation method of the titanium dioxide nano-particles with the surfaces rich in hydroxyl groups comprises the following steps:

The preparation method of the silanized titanium dioxide nano-particles comprises the following steps:

The silane coupling agent is one or more of methyltrimethoxysilane, vinyltrimethoxysilane, gamma-aminopropyl trimethoxysilane, trimethoxy (propyl) silane, trimethylchlorosilane, tetraethyl orthosilicate and propyl trimethoxy silane.

The mass ratio of the silanized titanium dioxide nano particles to the polylactic acid to the mixed solvent is 0.05-0.3:1-3:10.

The mixed solvent consists of a solvent A and a solvent B according to the mass ratio of 7-10:1.5-4.5, wherein the solvent A is chloroform or methylene dichloride, and the solvent B is any one of dimethylformamide, ethyl acetate and formic acid.

The electrostatic spinning voltage is 15KV, the spinning flow rate is 1.0mL/h, and the spinning distance is 15cm.

Example 1

Step 1, dropwise adding 5g of tetrabutyl titanate into 5mL of deionized water, stirring at a low temperature of 4 ℃ for reaction for 2 hours, centrifuging for precipitation, and annealing at an oven of 80 ℃ for 8 hours to obtain titanium dioxide nano particles rich in hydroxyl groups;

Step 2, taking 2g of the titanium dioxide nano particles rich in hydroxyl groups, 5mL of deionized water and 5mL of deionized water obtained in the step 1, placing the titanium dioxide nano particles into a vacuum closed container, treating the titanium dioxide nano particles for 2 hours at 100 ℃ in vacuum (less than 0.1 Pa), washing the titanium dioxide nano particles with absolute ethyl alcohol, centrifuging, precipitating, and freeze-drying to obtain silanized titanium dioxide nano particles;

And 3, performing ultrasonic dispersion on 0.05g of the silanized titanium dioxide nano particles and 10mL of a mixed solvent which consists of chloroform and dimethylformamide according to a mass ratio of 7:3 for 10min to obtain a homogeneous precursor solution, adding 1g of polylactic acid, stirring and dispersing to be transparent to obtain a spinning solution, and performing electrostatic spinning on the spinning solution, wherein the electrostatic spinning voltage is 15KV, the spinning flow rate is 1.0mL/h, and the spinning distance is 15cm to obtain the oil-water separation film.

The oil-water separation film obtained in example 1 is shown in fig. 1, and it can be seen from fig. 1 that the film can be prepared in large scale, and has good integrity even after continuous folding.

Example 2

step 1, dropwise adding 1.5g of tetrabutyl titanate into 8mL of deionized water, stirring at a low temperature of 4 ℃ for reaction for 2 hours, centrifuging for precipitation, and annealing at a temperature of 100 ℃ for 8 hours in an oven to obtain titanium dioxide nano particles rich in hydroxyl groups;

Step 2, taking 2g of the titanium dioxide nano particles rich in hydroxyl groups, 5mL of deionized water and 5mL of deionized water obtained in the step 1, placing the titanium dioxide nano particles into a vacuum closed container, treating the titanium dioxide nano particles for 2 hours at 125 ℃ in vacuum (less than 0.1 Pa), washing the titanium dioxide nano particles with absolute ethyl alcohol, centrifuging, precipitating, and freeze-drying to obtain silanized titanium dioxide nano particles;

And 3, dispersing 0.2g of the silanized titanium dioxide nano particles and 10mL of a mixed solvent consisting of chloroform and ethyl acetate according to a mass ratio of 7:3 for 10min by ultrasonic, obtaining a homogeneous precursor solution, adding 2g of polylactic acid, stirring and dispersing to be transparent, obtaining a spinning solution, and carrying out electrostatic spinning on the spinning solution, wherein the electrostatic spinning voltage is 15KV, the spinning flow rate is 1.0mL/h, and the spinning distance is 15cm, thus obtaining the oil-water separation film.

Example 3

step 1, dropwise adding 2g of tetrabutyl titanate into 10mL of deionized water, stirring at a low temperature of 4 ℃ for reaction for 2 hours, centrifuging for precipitation, and annealing at a temperature of 120 ℃ for 8 hours in an oven to obtain titanium dioxide nano particles rich in hydroxyl groups;

step 2, taking 2g of the titanium dioxide nano particles rich in hydroxyl groups, 5mL of deionized water and 5mL of deionized water obtained in the step 1, placing the titanium dioxide nano particles into a vacuum closed container, treating the titanium dioxide nano particles for 2 hours at 150 ℃ in vacuum (less than 0.1 Pa), washing the titanium dioxide nano particles with absolute ethyl alcohol, centrifuging, precipitating, and freeze-drying to obtain silanized titanium dioxide nano particles;

And 3, dispersing 0.3g of the silanized titanium dioxide nano particles and 10mL of a mixed solvent consisting of dichloromethane and ethyl acetate according to a mass ratio of 7:3 for 10min by ultrasonic, obtaining a homogeneous precursor solution, adding 3g of polylactic acid, stirring and dispersing to be transparent, obtaining a spinning solution, and carrying out electrostatic spinning on the spinning solution, wherein the electrostatic spinning voltage is 15KV, the spinning flow rate is 1.0mL/h, and the spinning distance is 15cm, thus obtaining the oil-water separation film.

Comparative example 1

And 2, performing ultrasonic dispersion on 0.05g of titanium dioxide nano particles rich in hydroxyl and 10mL of mixed solvent consisting of chloroform and dimethylformamide according to a mass ratio of 7:3 for 10min to obtain a homogeneous precursor solution, adding 1g of polylactic acid, stirring and dispersing to be transparent to obtain a spinning solution, and performing electrostatic spinning on the spinning solution, wherein the electrostatic spinning voltage is 15KV, the spinning flow rate is 1.0mL/h, and the spinning distance is 15cm to obtain the oil-water separation film.

The oil-water separation films obtained by the preparation methods described in example 1, example 2, example 3 and comparative example 1 were observed by using a scanning electron microscope, wherein fig. 2a is a scanning electron microscope image of the oil-water separation film of comparative example 1, fig. 2b is a scanning electron microscope image of the oil-water separation film of example 1, fig. 2c is a scanning electron microscope image of the oil-water separation film of example 2, and fig. 2c is a scanning electron microscope image of the oil-water separation film of example 3, and it can be seen from fig. 2 that example 3 shows more abundant porosity compared with example 2 and example 1 with the addition of the silylated titanium dioxide nanoparticles. The silane functional groups on the silanized titanium dioxide nano particles can build an effective cross-linked network system in the system, so that the multilevel pore structure of the material is enriched. Comparative example 1 was poor in interfacial compatibility with polylactic acid because it was not subjected to silylation treatment.

The oil-water separation films obtained by the preparation methods described in example 1 and comparative example 1 were subjected to a hydrophilic contact angle test, wherein fig. 3a is a hydrophilic contact angle measurement image of comparative example 1 and fig. 3b is a hydrophilic contact angle measurement image of example 1. The results show that example 1 has a contact angle greater than that of comparative example 1, showing that example 1 is more hydrophobic than comparative example 1. This phenomenon indicates that the introduction of the silylated titanium dioxide nanoparticles in example 1 results in a decrease in the hydrophilicity of the oil-water separation membrane. In particular, a larger hydrophilic contact angle means that the example surface has poor wettability with an aqueous liquid, and the surface energy is lowered, thereby reducing the wettability with water. In contrast, the smaller hydrophilic contact angle of the comparative example 1 film indicates that the surface thereof is more wettable to water.

The oil-water separation films obtained by the preparation methods described in example 1 and comparative example 1 were subjected to an oleophilic contact angle test, wherein fig. 4a is an oleophilic contact angle measurement image of comparative example 1, and fig. 4b is an oleophilic contact angle measurement image of example 1. The results show that the oleophilic contact angle of example 1 is smaller, whereas the oleophilic contact angle of comparative example 1 is larger. This indicates that example 1 has a stronger lipophilicity, whereas comparative example 1 shows a relatively stronger lipophobicity. In particular, a smaller oleophilic contact angle indicates that the surface of example 1 has better wettability to oily liquids and higher surface energy, which is favorable for the infiltration of oily liquids. The silanized titanium dioxide nano particles are proved to improve the lipophilicity of the oil-water separation film.

The oil-water separation films obtained by the preparation methods of example 1 and comparative example 1 were subjected to a hydrophilic contact angle stability test, as shown in fig. 5, and fig. 5 shows graphs of the hydrophilic contact angles versus time for comparative example 1 and example 1, and the results indicate that both comparative example 1 and example 1 exhibit stable hydrophobicity.

The oil-water separation films obtained by the preparation methods of example 1 and comparative example 1 were subjected to an oleophilic contact angle stability test, as shown in fig. 6, and fig. 6 shows graphs of the oleophilic contact angles versus time for comparative example 1 and example 1, which revealed that comparative example 1 exhibited slower stable oil absorption compared to example 1.

The oil-water separation test was performed on the oil-water separation films obtained by the preparation methods described in example 1 and comparative example 1, and fig. 7 shows a schematic diagram of an oil-water separation device, in which 10mL of n-hexadecane was mixed with 30mL of deionized water at an oil-water volume ratio of 1:3. Sudan II dye is added into n-hexadecane for dyeing, and deionized water keeps undyed.

Fig. 8 shows oil-water separation flow charts of comparative example 1, example 2 and example 3, in which the n-hexadecane flux of the oil-water separation membrane was obtained according to a membrane flux calculation formula:

Product (m ²), t is the operating time (h).

It can be seen that example 1 exhibited a more pronounced flux of the oil-water separation membrane than comparative example 1, wherein the flux of the oil-water separation membrane was gradually increased with the addition of the silylated titanium dioxide nanoparticles.

It is noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. A method for preparing an oil-water separation film, characterized in that it comprises the following steps:

Step 1: hydrolyzing and annealing tetrabutyl titanate to obtain titanium dioxide nanoparticles with a rich surface hydroxyl group;

Step 2: modifying the above hydroxyl-rich titanium dioxide nanoparticles to obtain silanized titanium dioxide nanoparticles;

Step 3: ultrasonically disperse the silanized titanium dioxide nanoparticles in a mixed solvent for 10 minutes to obtain a homogeneous precursor solution, add polylactic acid, stir and disperse until transparent to obtain a spinning solution, and electrospin the spinning solution to obtain an oil-water separation film.

2. The method for preparing an oil-water separation membrane according to claim 1, characterized in that the specific preparation steps of the silanized titanium dioxide nanoparticles are as follows:

Hydroxyl-rich titanium dioxide nanoparticles, ionized water and silane coupling agent were mixed in a ratio of 2g:5mL:5mL, and then placed in a vacuum sealed container. The reaction was continued at 100-150°C for 2 hours. After the reaction was completed, the mixture was washed with anhydrous ethanol, centrifuged and freeze-dried to obtain silanized titanium dioxide nanoparticles.

3. The method for preparing an oil-water separation film according to claim 2, characterized in that the silane coupling agent is any one or more of methyltrimethoxysilane, vinyltrimethoxysilane, γ-aminopropyltrimethoxysilane, trimethoxy(propyl)silane, trimethylchlorosilane, tetraethyl orthosilicate and propyltrimethoxysilane.

4. The method for preparing an oil-water separation film according to claim 2, characterized in that the mass ratio of silanized titanium dioxide nanoparticles, polylactic acid and mixed solvent is 0.05-0.3:1-3:10.

5. The method for preparing an oil-water separation film according to claim 2, characterized in that the mixed solvent consists of solvent A and solvent B in a mass ratio of 7-10:1.5-4.5, solvent A is chloroform or dichloromethane, and solvent B is any one of dimethylformamide, ethyl acetate and formic acid.

6. The method for preparing an oil-water separation membrane according to claim 1, characterized in that the electrospinning voltage is 15KV, the spinning flow rate is 1.0mL/h, and the spinning distance is 15cm.

7. A method for preparing an oil-water separation film according to any one of claims 1 to 6, characterized in that the prepared film is used in the field of oil-water separation.