CN103480281A - Organic-inorganic ultrafiltration composite membrane and preparation method thereof - Google Patents

Abstract

An organic-inorganic ultrafiltration composite membrane and a preparation method thereof. The composite film is composed of the following components in parts by weight: 15-20 parts of polymer resin, silane functionalized graphene oxide accounting for 0.02-2.0% of polymer resin, 75-90 parts of N-N dimethylacetamide and 1- 3 parts polyvinylpyrrolidone. The advantages of the present invention are: the film-making process is simple and easy to realize; the silane functionalized graphene oxide is well dispersed into the polymer matrix through ultrasonic and mechanical stirring; Strong binding performance, ultra-high specific surface area and long polymer chains on the surface make it well dispersed in the polymer matrix. In addition, the abundant oxygen-containing functional groups on the surface of silane-functionalized graphene oxide can be easily Better enhance the hydrophilicity of the ultrafiltration composite membrane, and then synergistically improve the mechanical properties and anti-pollution performance of the ultrafiltration composite membrane.

Description

An organic-inorganic ultrafiltration composite membrane and its preparation method

technical field

The invention belongs to the technical field of functional modification of ultrafiltration membranes, and in particular relates to a silane functionalized graphene oxide modified organic-inorganic ultrafiltration composite membrane and a preparation method thereof.

Background technique

As an ultrafiltration membrane material with excellent comprehensive performance, organic polymer has good chemical stability, thermal stability and porosity, but due to its low surface energy and strong hydrophobicity, it is easy to cause surface pollution. Thereby seriously affecting the performance of the product. In recent years, in view of the problem of easy fouling of polymer ultrafiltration membranes, the research on its hydrophilic blending modification has gradually become active. The reported modified materials mainly include SiO ₂ , Fe ₂ O ₃ , Al ₂ O ₃ , TiO ₂ And low-dimensional carbon nanomaterials such as carbon oxide nanotubes and inorganic materials such as graphene derivatives. Although the use of these materials to modify the polymer ultrafiltration membrane can increase the permeation flux of the membrane and greatly improve the functional performance, however, these methods also have some shortcomings, which are mainly manifested in: (1) The relationship between the modified material and the polymerization The weak interfacial bonding between the substrates increases the interfacial defects, resulting in a decrease in the mechanical strength of the modified ultrafiltration composite membrane; (2) due to the lack of abundant functional groups on the surface of inorganic particles, the particles are prone to agglomeration, which affects the ultrafiltration composite membrane. performance of composite membranes. Therefore, it is necessary to find a method that can not only increase the mechanical properties of ultrafiltration composite membranes but also strengthen their anti-fouling properties.

Contents of the invention

In order to solve the above problems, the object of the present invention is to provide a silane-functionalized graphene oxide modified organic-inorganic ultrafiltration composite membrane capable of improving its mechanical properties and anti-pollution properties and its preparation method.

In order to achieve the above object, the organic-inorganic ultrafiltration composite membrane provided by the invention is made up of the following components in parts by weight:

The polymer resin is selected from one of polyvinylidene fluoride, polyacrylonitrile, polysulfone and polyurethane.

2. The organic-inorganic ultrafiltration composite membrane according to claim 1, characterized in that the silane in the silane-functionalized graphene oxide is γ-aminopropyltriethoxysilane (KH550).

3. A method for preparing an organic-inorganic ultrafiltration composite membrane as claimed in claim 1, characterized in that: said preparation method comprises the following steps in order:

1) Add the silane-functionalized graphene oxide weighed according to the above weight ratio to N-N dimethylacetamide, and then ultrasonically treat it for 0.5-2 hours to make it uniformly dispersed;

2) Then add the polymer resin and polyvinylpyrrolidone weighed according to the above weight ratio, and then mechanically stir for 5 to 24 hours to obtain a casting solution in which silane-functionalized graphene oxide is uniformly dispersed;

3) Put the above-mentioned casting solution at 20-30°C for 1-3 days to defoam, then scrape the film at 15-30°C, and volatilize the casting solution in the air for 10-100 After a few seconds, slowly put it into the deionized water coagulation solution to form a film;

4) The membrane was taken out from the coagulation solution and rinsed with deionized water to prepare a silane-functionalized graphene oxide-modified organic-inorganic ultrafiltration composite membrane.

The organic-inorganic ultrafiltration composite membrane provided by the invention uses graphene oxide functionalized with γ-aminopropyltriethoxysilane (KH550) to enhance the mechanical properties and anti-pollution properties of the polymer ultrafiltration membrane. The abundant oxygen-containing functional groups in graphene oxide enhance the hydrophilicity of the ultrafiltration composite membrane, thereby enhancing its anti-pollution performance. On the other hand, while fully retaining the functional groups of graphene oxide, long polymer chains are introduced to make the polymer chain fully It penetrates deep into the polymer matrix, so it can well enhance the interfacial bonding between the functionalized graphene oxide and the polymer matrix, and greatly improve the dispersion of the functionalized graphene oxide in the polymer matrix, so as to achieve ultra- The mechanical properties and antifouling performance of the filter composite membrane are synergistically enhanced.

The advantages of the present invention are: the film-making process is simple and easy to realize; the silane functionalized graphene oxide is well dispersed into the polymer matrix through ultrasonic and mechanical stirring; Strong binding performance, ultra-high specific surface area and long polymer chains on the surface make it well dispersed in the polymer matrix. In addition, the abundant oxygen-containing functional groups on the surface of silane-functionalized graphene oxide can be easily It can well enhance the hydrophilicity of the ultrafiltration composite membrane, and then significantly improve the mechanical properties and anti-pollution performance of the ultrafiltration composite membrane. In addition, the addition of silane-functionalized graphene oxide has no effect on the original excellent properties of the polymer resin, but also increases the spatial connection of the membrane and prolongs the service life of the membrane.

Detailed ways

Example 1

0.075g of γ-aminopropyltriethoxysilane functionalized graphene oxide was ultrasonically dispersed in 84g of N-N dimethylacetamide as a solvent, and 15g of polyvinylidene fluoride and 1g of polyvinylpyrrolidone as a porogen were added after 2h , then heat and stir in a water bath at 450°C for 24 hours, let stand for degassing for 24 hours, use a self-made scraper to control a certain thickness of the liquid film and scrape the film on a clean glass plate, pre-evaporate for 30 seconds, immerse in deionized water to solidify, and repeat The water is changed to remove the solvent and the porogen, and finally the silane functionalized graphene oxide modified organic-inorganic ultrafiltration composite membrane can be prepared.

The organic-inorganic ultrafiltration composite membrane was soaked in deionized water for 3 days, and then the mechanical strength and anti-pollution performance of the ultrafiltration composite membrane were tested by using a mechanical stretching device and a permeation filtration device. The results showed that the ultrafiltration provided by this embodiment The mechanical strength of the composite membrane is 42.86% higher than that of the pure polyvinylidene fluoride membrane, and the anti-pollution performance is significantly improved, and the irreversible pollution coefficient is reduced by about 60%.

Example 2

0.15g of γ-aminopropyltriethoxysilane functionalized graphene oxide was ultrasonically dispersed in 83g of N-N dimethylacetamide, 15g of polyacrylonitrile and 1g of polyvinylpyrrolidone were added after 1h, and then heated in a water bath at 50°C Stir for 30 hours, stand for defoaming for 24 hours, use a self-made scraper to control a certain thickness of the liquid film on a clean glass plate, pre-evaporate for 30 seconds, immerse in deionized water to solidify, and change the water repeatedly to remove the solvent and porogen , and finally the silane functionalized graphene oxide modified organic-inorganic ultrafiltration composite membrane can be prepared.

The organic-inorganic ultrafiltration composite membrane was soaked in deionized water for 4 days, and then the mechanical strength and anti-pollution performance of the ultrafiltration composite membrane were tested by using a mechanical stretching device and a osmotic filtration device. The results showed that the ultrafiltration provided by this embodiment The mechanical strength of the composite membrane is 50% higher than that of the pure polyacrylonitrile membrane, and the anti-pollution performance is significantly improved, and the irreversible pollution coefficient is reduced by about 40%.

Example 3

Ultrasonic dispersion of 0.1g of γ-aminopropyltriethoxysilane functionalized graphene oxide in 77g of N-N dimethylacetamide, 20g of polysulfone and 3g of polyvinylpyrrolidone was added after 2h, and then heated and stirred in a water bath at 40°C 20h, stand for defoaming for 30h, use a self-made scraper to control a certain thickness of the liquid film and scrape the film on a clean glass plate, pre-evaporate for 30 seconds, immerse in deionized water to solidify, and change the water repeatedly to remove the solvent and porogen. Finally, the silane functionalized graphene oxide modified organic-inorganic ultrafiltration composite membrane can be prepared.

The organic-inorganic ultrafiltration composite membrane was soaked in deionized water for 4 days, and then the mechanical strength and anti-pollution performance of the ultrafiltration composite membrane were tested by using a mechanical stretching device and a osmotic filtration device. The results showed that the ultrafiltration provided by this embodiment The mechanical strength of the composite membrane is 35.68% higher than that of the pure polysulfone membrane, and the anti-pollution performance is significantly improved, and the irreversible pollution coefficient is reduced by about 60%.

Example 4

Ultrasonic dispersion of 0.2g of γ-aminopropyltriethoxysilane functionalized graphene oxide in 79g of N-N dimethylacetamide, 20g of polyurethane and 3g of polyvinylpyrrolidone was added after 2h, and then heated and stirred in a water bath at 45°C for 30h , stand for defoaming for 24 hours, use a self-made scraper to control a certain thickness of the liquid film on a clean glass plate, scrape the film on a clean glass plate, pre-evaporate for 30 seconds, immerse in deionized water to solidify, and change the water repeatedly to remove the solvent and porogen, and finally The organic-inorganic ultrafiltration composite membrane modified by the silane functionalized graphene oxide can be prepared.

The organic-inorganic ultrafiltration composite membrane was soaked in deionized water for 3 days, and then the mechanical strength and anti-pollution performance of the ultrafiltration composite membrane were tested by using a mechanical stretching device and a permeation filtration device. The results showed that the ultrafiltration provided by this embodiment The mechanical strength of the composite membrane is 65.71% higher than that of the pure polyurethane membrane, and the anti-pollution performance is significantly improved, and the irreversible pollution coefficient is reduced by about 30%.

Claims (3)

1. an organic and inorganic ultrafiltration composite membrane, it is characterized in that: described organic and inorganic ultrafiltration composite membrane is comprised of the following component in weight portion:

Described fluoropolymer resin is selected from a kind of in Kynoar, polyacrylonitrile, polysulfones and polyurethane.

2. organic and inorganic ultrafiltration composite membrane according to claim 1, it is characterized in that: the silane in described silane-functionalized graphene oxide is gamma-aminopropyl-triethoxy-silane (KH550).

3. the preparation method of an organic and inorganic ultrafiltration composite membrane as claimed in claim 1, it is characterized in that: described preparation method comprises the following step carried out in order:

The silane-functionalized graphene oxide that 1) will take according to above-mentioned weight ratio joins in the N-N dimethylacetylamide, then ultrasonic processing 0.5～2 hour so that its be uniformly dispersed;

2) then add fluoropolymer resin and the polyvinylpyrrolidone taken according to above-mentioned weight ratio, afterwards mechanical agitation 5～24 hours and obtain the finely dispersed casting solution of silane-functionalized graphene oxide;

3) then the static placement under 20～30 ℃ of above-mentioned casting solution is carried out to knifing to carry out deaeration in 1～3 day under 15～30 ℃, after the casting solution after knifing volatilizees 10～100 seconds in air, it is slowly put into to deionized water solidification liquid film forming;

4) take out film from solidification liquid and rinse well by deionized water, make the organic and inorganic ultrafiltration composite membrane of silane-functionalized graphene oxide modification.