A PMMA super-hydrophobic particle / fiber composite filter membrane and a preparation method thereof

Abstract

The application discloses a PMMA super-hydrophobic particle / fiber composite filter membrane and a preparation method thereof. A certain amount of PMMA is added into an organic solvent, and is ultrasonically stirred until completely dissolved to obtain a low-concentration and high-concentration PMMA solution. The low-concentration and high-concentration PMMA solution is prepared into a PMMA particle / fiber composite membrane through a coaxial electrostatic spinning process, and the PMMA super-hydrophobic particle / fiber composite filter membrane is obtained after drying at 60 DEG C. The PMMA super-hydrophobic particle / fiber composite filter membrane has the advantages that PMMA is low in price and has no other functional dopant, cost can be saved, PMMA is environment-friendly, and the preparation process is simple and continuous, which is helpful to industrialization. The composite structure of the particles and the fibers enables the PMMA filter membrane to have super-hydrophobic performance, and the PMMA filter membrane has a wide application prospect in the field of oil-water separation and has a very important significance for water resource purification in China.

Description

Technical Field

[0001] This invention belongs to the field of separation composite membrane preparation technology, specifically relating to a PMMA superhydrophobic particle / fiber composite filter membrane and its preparation method. Background Technology

[0002] In recent years, water pollution has intensified, with oily wastewater from daily life, industrial production, and oil spills being the most prevalent. Water pollution has become a serious environmental problem that urgently needs to be addressed. Membrane separation technology is one of the most promising high-tech solutions, possessing advantages such as high separation efficiency, simple preparation process, small footprint, low energy consumption, and no pollution. It has been widely applied in fields such as seawater desalination, industrial wastewater treatment, and environmental pollution control.

[0003] With the increasing maturity of membrane separation technology, the preparation of high-performance composite membrane materials by combining nanoparticles with high specific surface area and easy modification with fiber materials has become a research hotspot. Common methods for preparing composite membrane materials include mixed spinning, impregnation, and surface coating. However, the latter two methods suffer from problems such as particle agglomeration and detachment. The development of electrospinning technology has also made mixed spinning a research hotspot in the field. Currently, commonly used membrane materials include polyvinyl chloride, polyacrylonitrile, polyvinylidene fluoride, and polystyrene. However, these materials have drawbacks such as poor separation performance, low cost-effectiveness, or difficulty in degradation, which restricts the development of membrane separation technology. Therefore, it is necessary to find a membrane material that is inexpensive, has good separation performance, and is environmentally friendly. Polymethyl methacrylate (PMMA) is mainly obtained by polymerizing acrylic acid and its esters. It has many advantages such as being non-toxic, environmentally friendly, low-cost, and easy to process, and is widely used in the fields of medicine, health, and building materials, but its application in water purification is relatively limited.

[0004] Chinese patent CN201810156617.0 discloses a high-efficiency, low-resistance multilayer electrospun nanofiber composite membrane and its preparation method. The method involves adding a dried polymer 1 to solvent A and stirring uniformly under sealed conditions at 80°C until fully dissolved, resulting in a colorless and transparent liquid solution with a polymer 1 concentration of 10%–25% by mass. Then, the dried polymer 1 and a dispersion of surface-modified MWCNTs are sequentially added to solvent B and stirred uniformly under sealed conditions at 80°C until fully dissolved, yielding a MWCNTs / polymer 2 solution with a MWCNTs concentration of 0.05%–0.3% by mass and a polymer 2 concentration of 5%–10% by mass. Polymer 2 is one of polyacrylonitrile (PAN), polymethyl methacrylate (PMMA), polyphenylene sulfone (PPSU), and polyetherimide (PEI). The multilayer electrospun nanofiber composite membrane is composed of a substrate, a nanofiber layer, and a protective material. The nanofiber layer consists of three layers of nanofibers. A method for preparing the multilayer electrospun nanofiber composite membrane is also disclosed, improving the spinning solution formulation and spinning process to overcome the shortcomings of existing technologies and products. Through linear electrode electrospinning, air filtration products with high filtration efficiency, low pressure resistance, and good mechanical properties can be prepared simply and efficiently, possessing significant application and industrialization value. However, considering the complexity of operation and high cost, the existing technology is somewhat inadequate. Summary of the Invention

[0005] Technical problems to be solved:

[0006] This application addresses the shortcomings of existing technologies and solves the technical problems of easy particle aggregation and detachment. It provides a PMMA superhydrophobic particle / fiber composite filter membrane and its preparation method, which makes full use of the characteristic that the electrospinning morphology of PMMA at different concentrations is different, and prepares a pure PMMA particle / fiber composite filter membrane.

[0007] Technical solution:

[0008] To achieve the above objectives, this application provides the following technical solution:

[0009] A method for preparing a PMMA superhydrophobic particle / fiber composite filter membrane, the method specifically including the following steps:

[0010] Step 1: Add a certain amount of PMMA to an organic solvent and ultrasonically stir until completely dissolved to obtain low-concentration and high-concentration PMMA solutions;

[0011] Step 2: PMMA particle / fiber composite membranes are prepared by coaxial electrospinning of low-concentration and high-concentration PMMA solutions, and dried at 60°C to obtain PMMA superhydrophobic particle / fiber composite filter membranes.

[0012] Further, the organic solvent in the first step is a solution of N,N-dimethylformamide (DMF) and tetrahydrofuran (THF) mixed in equal proportions; the low concentration PMMA solution has a weight percentage of 3-8 wt%, and the high concentration PMMA solution has a weight percentage of 15-20 wt%.

[0013] Furthermore, in the second step, the coaxial electrospinning process has a core solution flow rate of 5-15 μl / min and a shell solution flow rate of 10-20 μl / min; a spinning voltage of 15-20 kV; a receiving distance of 10-20 cm; and a 10-50 mesh steel wire mesh as the receiving substrate.

[0014] Furthermore, in the coaxial electrospinning process, 15-20 wt% PMMA solution is used as the core solution and 3-8 wt% PMMA solution is used as the shell solution.

[0015] This application also discloses a PMMA superhydrophobic particle / fiber composite filter membrane prepared by the above preparation method.

[0016] The principle of the above-mentioned PMMA superhydrophobic particle / fiber composite filter membrane and its preparation method is as follows: PMMA can be dissolved in organic solvents, and the form obtained by electrospinning low-concentration PMMA solution is particles, while the form obtained by electrospinning high-concentration solution is fibers; by controlling the concentration difference inside and outside the coaxial and the spinning process (voltage, receiving distance, speed), PMMA particles and fibers are stacked to form a composite membrane; PMMA itself has a certain degree of hydrophobicity, and the composite of particles and fibers can construct a micro-nano rough structure, so that the composite membrane obtains superhydrophobic properties.

[0017] Beneficial effects:

[0018] This application provides a PMMA superhydrophobic particle / fiber composite filter membrane and its preparation method, which has the following advantages compared with the prior art:

[0019] 1. Using inexpensive PMMA as raw material, without other functional additives, it can save costs. Furthermore, PMMA is environmentally friendly and complies with national energy conservation and environmental protection policies.

[0020] 2. The preparation process has the advantages of being simple to operate and continuous, which is conducive to industrialization.

[0021] 3. The composite structure of particles and fibers gives PMMA filter membranes superhydrophobic properties, which has broad application prospects in the field of oil-water separation and is of great significance to water resource purification in my country.

[0022] 4. The fiber / particle PMMA composite membrane has a contact angle of 156°, exhibiting superhydrophobic properties.

[0023] 5. Fiber / particle PMMA composite membranes can achieve excellent oil-water separation performance with a separation efficiency of up to 99.5%. Attached image description:

[0024] Figure 1 The image shows a scanning electron microscope (SEM) image of the PMMA particle fiber composite membrane prepared by the technical method of the present invention.

[0025] Figure 2 This is a diagram showing the water contact angle of the superhydrophobic PMMA particle / fiber composite membrane of this application. Detailed Implementation

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] Example 1:

[0028] A method for preparing a PMMA superhydrophobic particle / fiber composite filter membrane specifically includes the following steps:

[0029] Step 1: Add 0.6186g PMMA to a mixed solution of 10.54ml DMF and 11.25ml THF, and sonicate until completely dissolved to obtain a PMMA solution with a mass fraction of 3wt%; add 3.529g PMMA to a mixed solution of 10.54ml DMF and 11.25ml THF, and sonicate until completely dissolved to obtain a PMMA solution with a mass fraction of 15wt%.

[0030] Step 2: Using a 15wt% PMMA solution as the core solution and a 3wt% PMMA solution as the shell solution, coaxial electrospinning was performed with a 10-mesh steel wire mesh as the receiving substrate. The spinning process was as follows: core solution flow rate 5 μl / min, shell solution flow rate 10 μl / min, spinning voltage 15 kV, and receiving distance 10 cm. Finally, the PMMA particle / fiber composite membrane was dried at 60℃.

[0031] Example 2:

[0032] A method for preparing a PMMA superhydrophobic particle / fiber composite filter membrane specifically includes the following steps:

[0033] Step 1: Add 1.053g PMMA to a mixed solution of 10.54ml DMF and 11.25ml THF, and sonicate until completely dissolved to obtain a PMMA solution with a mass fraction of 5wt%; add 4.390g PMMA to a mixed solution of 10.54ml DMF and 11.25ml THF, and sonicate until completely dissolved to obtain a PMMA solution with a mass fraction of 18wt%.

[0034] Step 2: Using an 18wt% PMMA solution as the core solution and a 5wt% PMMA solution as the shell solution, coaxial electrospinning was performed with a 30-mesh steel wire mesh as the receiving substrate. The spinning process was as follows: core solution flow rate 10 μl / min, shell solution flow rate 15 μl / min, spinning voltage 18 kV, and receiving distance 15 cm. Finally, the PMMA particle / fiber composite membrane was dried at 60℃.

[0035] Example 3:

[0036] A method for preparing a PMMA superhydrophobic particle / fiber composite filter membrane specifically includes the following steps:

[0037] Step 1: Add 1.739g PMMA to a mixed solution of 10.54ml DMF and 11.25ml THF, and sonicate until completely dissolved to obtain a PMMA solution with a mass fraction of 8wt%; add 5g PMMA to a mixed solution of 10.54ml DMF and 11.25ml THF, and sonicate until completely dissolved to obtain a PMMA solution with a mass fraction of 20wt%.

[0038] Step 2: Using a 20wt% PMMA solution as the core solution and an 8wt% PMMA solution as the shell solution, coaxial electrospinning was performed using a 50-mesh steel wire mesh as the receiving substrate. The spinning process was as follows: core solution flow rate 15 μl / min, shell solution flow rate 20 μl / min, spinning voltage 20 kV, and receiving distance 20 cm. Finally, the PMMA particle / fiber composite membrane was dried at 60℃.

[0039] The PMMA particle / fiber composite membranes prepared in the above three examples were characterized by water contact angle and oil-water separation tests to assess their hydrophobicity and membrane separation performance. The results are shown in Table 1.

[0040] Table 1. Hydrophobicity and oil-water separation performance of PMMA particle / fiber composite membranes

[0041]

[0042] The present invention has been described above by way of example. It should be noted that any simple modifications, alterations or other equivalent substitutions that can be made by those skilled in the art without creative effort without departing from the core of the present invention fall within the protection scope of the present invention.

Claims

1. A method for preparing a PMMA superhydrophobic particle / fiber composite filtration membrane, characterized in that, The preparation method of the PMMA super-hydrophobic particle / fiber composite filter membrane specifically comprises the following steps: Step 1: 1.053 g of PMMA is added into a mixed solution of 10.54 ml of DMF and 11.25 ml of THF, and ultrasonic stirring is performed until complete dissolution to obtain a 5wt% PMMA solution; 4.390 g of PMMA is added into a mixed solution of 10.54 ml of DMF and 11.25 ml of THF, and ultrasonic stirring is performed until complete dissolution to obtain an 18wt% PMMA solution; Step 2: the 18wt% PMMA solution is used as a core solution, the 5wt% PMMA solution is used as a shell solution, and coaxial electrospinning is performed on a 30-mesh steel wire mesh as a receiving substrate, with a spinning process of a core solution flow rate of 10 µl / min, a shell solution flow rate of 15 µl / min, a spinning voltage of 18 kv, and a receiving distance of 15 cm; and finally, the PMMA particle / fiber composite membrane is dried at 60°C.

2. A PMMA super-hydrophobic particle / fiber composite filter membrane prepared by the preparation method of claim 1.

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