阅读说明：本技术 一种纳米二氧化钛改性聚酰胺6复合滤膜材料和制法 (Nano titanium dioxide modified polyamide 6 composite filter membrane material and preparation method thereof ) 是由 周展宇 于 2020-12-21 设计创作，主要内容包括：本发明涉及污水处理技术领域,且公开了一种纳米二氧化钛改性聚酰胺6复合滤膜材料,聚酰胺6是一种工程塑料,有着优良的力学性能、亲水性、耐腐蚀性,纳米二氧化钛表面存在着大量的羟基,有着良好的分散性,同时热稳定性好、刚性高,以聚酰胺6为基体时,掺杂纳米二氧化钛改性得到的膜材料,能够显著提高材料的性能,纳米二氧化钛表面的羟基与对苯二异氰酸酯一端的-NCO反应对位的,对位的-NCO被己内酰胺封端,与己内酰胺单体反应,可以引发己内酰胺发生阴离子聚合,加入的己内酰胺钠引发活化剂己内酰胺接枝的纳米二氧化钛聚合,再在致孔剂和溶剂的作用下,得到纳米二氧化钛改性聚酰胺6复合滤膜材料。(The invention relates to the technical field of sewage treatment and discloses a nano titanium dioxide modified polyamide 6 composite filter membrane material, wherein polyamide 6 is engineering plastic with excellent mechanical property, hydrophilicity and corrosion resistance, a large amount of hydroxyl groups exist on the surface of nano titanium dioxide, the dispersibility is good, the thermal stability is good, the rigidity is high, when the polyamide 6 is taken as a matrix, the membrane material obtained by modifying nano titanium dioxide is doped, the performance of the material can be obviously improved, the hydroxyl groups on the surface of the nano titanium dioxide react with-NCO at one end of p-phenylene diisocyanate in a para-position, the para-NCO is blocked by caprolactam monomer and reacts with the caprolactam monomer to initiate caprolactam to carry out anionic polymerization, the added caprolactam sodium initiates the polymerization of the nano titanium dioxide grafted by an activating agent, and then under the action of a pore-foaming agent and a solvent, obtaining the nano titanium dioxide modified polyamide 6 composite filter membrane material.)

1. A nanometer titanium dioxide modified polyamide 6 composite filter membrane material is characterized in that: the nano titanium dioxide modified polyamide 6 composite filter membrane material and the preparation method thereof comprise the following steps:

(1) adding toluene, nano titanium dioxide and p-phenylene diisocyanate into a three-neck flask, uniformly mixing in a nitrogen atmosphere, adding dibutyltin dilaurate, and stirring to react to obtain isocyanate functionalized nano titanium dioxide;

(2) adding isocyanate functionalized nano titanium dioxide and caprolactam into a three-neck flask, heating and stirring, centrifuging, washing and drying to obtain caprolactam grafted titanium dioxide;

(3) adding caprolactam and caprolactam grafted titanium dioxide into a three-neck flask, heating at the temperature of 120-140 ℃, repeatedly vacuumizing, filling nitrogen, repeating for 3-5 times, adding sodium caprolactam, polymerizing at constant temperature under the condition of oil bath, placing the obtained sample in a Soxhlet extractor, and extracting for 18-24h by using methanol to obtain the nano titanium dioxide modified polyamide 6 composite material;

(4) mixing the nano titanium dioxide modified polyamide 6 composite filter membrane material, formic acid, 10% calcium chloride methanol solution, pore-foaming agent polyvinylpyrrolidone and polyethylene glycol, pouring the mixed solution on a glass plate, paving the mixed solution to form a film, standing the film, drying the film, standing the dried film in distilled water, and placing the dried film in a mixed solution of deionized water, glycerol and sodium bisulfite with the volume ratio of 118:24:1 to obtain the nano titanium dioxide modified polyamide 6 composite filter membrane material.

2. The nano titanium dioxide modified polyamide 6 composite filter membrane material as claimed in claim 1, which is characterized in that: the mass ratio of the nano titanium dioxide to the p-phenylene diisocyanate in the step (1) is 10: 45-60.

3. The nano titanium dioxide modified polyamide 6 composite filter membrane material as claimed in claim 1, which is characterized in that: in the step (1), the stirring reaction temperature is 50-70 ℃, and the stirring reaction time is 3-6 h.

4. The nano titanium dioxide modified polyamide 6 composite filter membrane material as claimed in claim 1, which is characterized in that: in the step (2), the mass ratio of the isocyanate functionalized nano titanium dioxide to the caprolactam is 10: 55-65.

5. The nano titanium dioxide modified polyamide 6 composite filter membrane material as claimed in claim 1, which is characterized in that: in the step (2), the temperature is increased to 90-105 ℃, and the reaction time is increased to 4-7 h.

6. The nano titanium dioxide modified polyamide 6 composite filter membrane material as claimed in claim 1, which is characterized in that: in the step (3), the mass ratio of the caprolactam to the nano titanium dioxide activating agent grafted with the caprolactam to the sodium caprolactam is 10:90-450: 10-15.

7. The nano titanium dioxide modified polyamide 6 composite filter membrane material as claimed in claim 1, which is characterized in that: the oil bath temperature in the step (3) is 170-190 ℃, and the oil bath time is 4-6 h.

8. The nano titanium dioxide modified polyamide 6 composite filter membrane material as claimed in claim 1, which is characterized in that: the mass ratio of the nano titanium dioxide modified polyamide 6 composite filter membrane material to the pore-foaming agent in the step (4) is 10: 2-4.

Technical Field

The invention relates to the technical field of sewage treatment, in particular to a nano titanium dioxide modified polyamide 6 composite filter membrane material and a preparation method thereof.

Background

Along with the development of industrial economy, the amount of waste water is more and more, a large amount of pollution and waste are caused to water resources, the water body pollution is an important component of environmental pollution and poses great threat to the health of people, a large amount of pollutants which are difficult to degrade and remove exist in the industrial waste water, the oily waste water is a pollution component which accounts for a large proportion of the water pollution, and how to treat the pollution becomes a research hotspot.

Common widely used wastewater treatment technologies include a chemical method, a physical method, a biological method and the like, but the problems of low efficiency, serious secondary pollution and the like generally exist, a membrane separation technology is a new technology, is a material with simple process, low energy consumption and good treatment effect, and is a technology with good prospect in the aspect of oily wastewater, a filtering membrane can be broadly divided into an organic membrane and an inorganic membrane, the organic membrane is mostly composed of polymers, polyamide 6 is used as a thermoplastic resin and has good mechanical property, good hydrophilicity, high mechanical strength and corrosion resistance, a single-component membrane structure cannot meet the market demand along with the development of the membrane technology, and the single membrane component usually has the characteristics of difficulty in simultaneously considering hydrophilicity, stability, corrosion resistance and the like, so that the development of a composite membrane is necessary, and a nano material such as silicon dioxide, Titanium dioxide and the like are used as materials with a large number of hydroxyl groups on the surface and high activity, and can generate interaction with a polymer matrix, and the obtained nano material modified polymer composite filter membrane can improve the stability of the material, hinder the motion of chain segments, and improve the stability, hydrophobic property, water flux, mechanical property and other properties of the material.

Technical problem to be solved

Aiming at the defects of the prior art, the invention provides a nano titanium dioxide modified polyamide 6 composite filter membrane material and a preparation method thereof, and the nano titanium dioxide modified polyamide 6 composite filter membrane material has better stability and water flux.

(II) technical scheme

In order to achieve the purpose, the invention provides the following technical scheme: a nanometer titanium dioxide modified polyamide 6 composite filter membrane material and a preparation method thereof comprise the following steps:

(1) adding toluene, nano titanium dioxide and p-phenylene diisocyanate into a three-neck flask, uniformly mixing in a nitrogen atmosphere, adding dibutyltin dilaurate, and stirring to react to obtain isocyanate functionalized nano titanium dioxide;

(2) adding isocyanate functionalized nano titanium dioxide and caprolactam into a three-neck flask, heating and stirring, centrifuging, washing and drying to obtain caprolactam grafted titanium dioxide;

(3) adding caprolactam and caprolactam grafted titanium dioxide into a three-neck flask, heating at the temperature of 120-140 ℃, repeatedly vacuumizing, filling nitrogen, repeating for 3-5 times, adding sodium caprolactam, polymerizing at constant temperature under the condition of oil bath, placing the obtained sample in a Soxhlet extractor, and extracting for 18-24h by using methanol to obtain the nano titanium dioxide modified polyamide 6 composite material;

(4) mixing the nano titanium dioxide modified polyamide 6 composite material, formic acid, 10% calcium chloride methanol solution, pore-foaming agent polyvinylpyrrolidone and polyethylene glycol, pouring the mixed solution on a glass plate, paving the mixed solution to form a film, standing the film, drying the film, standing the dried film in distilled water, and placing the dried film in a mixed solution of deionized water, glycerol and sodium bisulfite with the volume ratio of 118:24:1 to obtain the nano titanium dioxide modified polyamide 6 composite filter membrane material.

Preferably, the mass ratio of the nano titanium dioxide to the p-phenylene diisocyanate in the step (1) is 10: 45-60.

Preferably, the stirring reaction temperature in the step (1) is 50-70 ℃, and the stirring reaction time is 3-6 h.

Preferably, the mass ratio of the isocyanate functionalized nano titanium dioxide to the caprolactam in the step (2) is 10: 55-65.

Preferably, the temperature rising and stirring temperature in the step (2) is 90-105 ℃, and the temperature rising and stirring reaction time is 4-7 h.

Preferably, the mass ratio of the caprolactam, the caprolactam grafted nano titanium dioxide activating agent and the sodium caprolactam in the step (3) is 10:90-450: 10-15.

Preferably, the oil bath temperature in the step (3) is 170-.

Preferably, the mass ratio of the nano titanium dioxide modified polyamide 6 composite filter membrane material to the pore-foaming agent in the step (4) is 10: 2-4.

(III) advantageous technical effects

Compared with the prior art, the invention has the following chemical mechanism and beneficial technical effects:

the nanometer titanium dioxide modified polyamide 6 composite filter membrane material has the advantages that series defects of a single membrane component in the aspects of hydrophilicity, stability, corrosion resistance and the like are improved to a great extent, polyamide 6 is common engineering plastic and has excellent mechanical property, hydrophilicity and corrosion resistance, a large number of hydroxyl groups exist on the surface of nanometer titanium dioxide, the nanometer titanium dioxide composite filter membrane material has good dispersibility, meanwhile, the thermal stability is good, the rigidity is high, and when the polyamide 6 is used as a matrix, the membrane material obtained by doping the nanometer titanium dioxide for modification can obviously improve the performance of the material.

The nanometer titanium dioxide modified polyamide 6 composite filter membrane material is characterized in that under the catalytic action of dibutyltin dilaurate, hydroxyl on the surface of nanometer titanium dioxide reacts with-NCO at one end of p-phenylene diisocyanate in a para-position mode under the action of a steric hindrance effect, para-position-NCO is blocked by caprolactam and reacts with a caprolactam monomer to prepare an activator of caprolactam grafted nanometer titanium dioxide, the caprolactam can be initiated to carry out anionic polymerization, sodium caprolactam is added as an initiator to initiate the polymerization of the caprolactam grafted nanometer titanium dioxide of the activator to obtain a nanometer titanium dioxide modified polyamide 6 composite material, under the action of a pore-forming agent and a solvent, the exchange rate is reduced, the resistance is increased, the pore length of a film is shortened, the structure is converted, and the film is converted into a sponge shape, the titanium dioxide is taken as a reticular hole of a cross-linking point in the structure, so that the density of the membrane can be increased, and the nano titanium dioxide modified polyamide 6 composite filter membrane material film which has good thermal stability, good dispersibility and better corrosion resistance and water flux can be obtained.

Detailed Description

To achieve the above object, the present invention provides the following embodiments and examples: a preparation method of a nanometer titanium dioxide modified polyamide 6 composite filter membrane material comprises the following steps:

(1) adding toluene, nano titanium dioxide and p-phenylene diisocyanate into a three-neck flask, wherein the mass ratio of the nano titanium dioxide to the p-phenylene diisocyanate is 10:45-60, uniformly mixing in a nitrogen atmosphere, adding dibutyltin dilaurate, stirring and mixing, wherein the stirring reaction temperature is 50-70 ℃, and the stirring reaction time is 3-6 hours, so as to obtain isocyanate functionalized nano titanium dioxide;

(2) adding isocyanate functionalized nano titanium dioxide and caprolactam into a three-neck flask in a mass ratio of 10:55-65, heating and stirring at 90-105 ℃, reacting for 4-7h, centrifuging, washing and drying to obtain caprolactam grafted titanium dioxide;

(3) adding caprolactam and caprolactam grafted titanium dioxide into a three-neck flask, heating at the temperature of 120-140 ℃, repeatedly vacuumizing, filling nitrogen, repeating for 3-5 times, adding sodium caprolactam, a caprolactam and caprolactam grafted nano titanium dioxide activating agent and the sodium caprolactam in a mass ratio of 10:90-450:10-15, polymerizing at a constant temperature under the condition of an oil bath, wherein the oil bath temperature is 170-190 ℃, the oil bath time is 4-6h, placing the obtained sample in a Soxhlet extractor, and extracting with methanol for 18-24h to obtain the nano titanium dioxide modified polyamide 6 composite material;

(4) mixing the nano titanium dioxide modified polyamide 6 composite material, formic acid, 10% calcium chloride methanol solution, pore-foaming agent polyvinylpyrrolidone and polyethylene glycol, wherein the mass ratio of the nano titanium dioxide modified polyamide 6 composite material to the pore-foaming agent is 10:2-4, pouring the mixed solution on a glass plate, spreading the mixed solution to form a film, standing the film, drying the film, standing the film in distilled water, and placing the film in a mixed solution of deionized water, glycerol and sodium bisulfite with the volume ratio of 118:24:1 to obtain the nano titanium dioxide modified polyamide 6 composite filter membrane material.

Example 1

(1) Adding toluene, nano titanium dioxide and p-phenylene diisocyanate into a three-neck flask, wherein the mass ratio of the nano titanium dioxide to the p-phenylene diisocyanate is 10:45, uniformly mixing in a nitrogen atmosphere, adding dibutyltin dilaurate, stirring and mixing, wherein the stirring reaction temperature is 50 ℃, and the stirring reaction time is 3 hours, so as to obtain isocyanate functionalized nano titanium dioxide;

(2) adding isocyanate functionalized nano titanium dioxide and caprolactam into a three-neck flask in a mass ratio of 10:55, heating and stirring at 90 ℃, reacting for 4 hours, centrifuging, washing and drying to obtain caprolactam grafted titanium dioxide;

(3) adding caprolactam and caprolactam grafted titanium dioxide into a three-neck flask, heating to 120 ℃, repeatedly vacuumizing, filling nitrogen, repeating for 3 times, then adding sodium caprolactam, caprolactam and caprolactam grafted nano titanium dioxide activating agent and sodium caprolactam in a mass ratio of 10:90:10, polymerizing under the condition of oil bath at a constant temperature, wherein the oil bath temperature is 170 ℃, the oil bath time is 4 hours, placing the obtained sample in a Soxhlet extractor, and extracting for 18 hours by using methanol to obtain the nano titanium dioxide modified polyamide 6 composite material;

(4) mixing the nano titanium dioxide modified polyamide 6 composite material, formic acid, 10% calcium chloride methanol solution, pore-foaming agent polyvinylpyrrolidone and polyethylene glycol, wherein the mass ratio of the nano titanium dioxide modified polyamide 6 composite material to the pore-foaming agent is 10:2, pouring the mixed solution on a glass plate, spreading the mixed solution to form a film, standing the film, drying the film, standing the film in distilled water, and placing the film in a mixed solution of deionized water, glycerol and sodium bisulfite with the volume ratio of 118:24:1 to obtain the nano titanium dioxide modified polyamide 6 composite filter membrane material.

Example 2

(1) Adding toluene, nano titanium dioxide and p-phenylene diisocyanate into a three-neck flask, wherein the mass ratio of the nano titanium dioxide to the p-phenylene diisocyanate is 10:50, uniformly mixing in a nitrogen atmosphere, adding dibutyltin dilaurate, stirring and mixing, wherein the stirring reaction temperature is 55 ℃, and the stirring reaction time is 4 hours, so as to obtain isocyanate functionalized nano titanium dioxide;

(2) adding isocyanate functionalized nano titanium dioxide and caprolactam into a three-neck flask in a mass ratio of 10:58, heating and stirring at 95 ℃, reacting for 5 hours, centrifuging, washing and drying to obtain caprolactam grafted titanium dioxide;

(3) adding caprolactam and caprolactam grafted titanium dioxide into a three-neck flask, heating at 125 ℃, repeatedly vacuumizing, filling nitrogen, repeating for 4 times, adding sodium caprolactam, caprolactam and caprolactam grafted nano titanium dioxide activating agent and sodium caprolactam in a mass ratio of 10:160:11, polymerizing under the condition of oil bath at constant temperature, wherein the oil bath temperature is 175 ℃, the oil bath time is 5 hours, placing the obtained sample in a Soxhlet extractor, and extracting for 20 hours by using methanol to obtain the nano titanium dioxide modified polyamide 6 composite material;

(4) mixing the nano titanium dioxide modified polyamide 6 composite material, formic acid, 10% calcium chloride methanol solution, pore-foaming agent polyvinylpyrrolidone and polyethylene glycol, wherein the mass ratio of the nano titanium dioxide modified polyamide 6 composite material to the pore-foaming agent is 10:2.5, pouring the mixed solution on a glass plate, spreading the mixed solution to form a film, standing the film, drying the film, standing the film in distilled water, and placing the film in a mixed solution of deionized water, glycerol and sodium bisulfite with the volume ratio of 118:24:1 to obtain the nano titanium dioxide modified polyamide 6 composite filter membrane material.

Example 3

(1) Adding toluene, nano titanium dioxide and p-phenylene diisocyanate into a three-neck flask, wherein the mass ratio of the nano titanium dioxide to the p-phenylene diisocyanate is 10:55, uniformly mixing in a nitrogen atmosphere, adding dibutyltin dilaurate, stirring and mixing, wherein the stirring reaction temperature is 65 ℃, and the stirring reaction time is 5 hours, so as to obtain isocyanate functionalized nano titanium dioxide;

(2) adding isocyanate functionalized nano titanium dioxide and caprolactam into a three-neck flask in a mass ratio of 10:62, heating and stirring at 100 ℃, reacting for 6 hours, centrifuging, washing and drying to obtain caprolactam grafted titanium dioxide;

(3) adding caprolactam and caprolactam grafted titanium dioxide into a three-neck flask, repeatedly vacuumizing and filling nitrogen at the heating temperature of 135 ℃, repeating for 4 times, then adding sodium caprolactam, caprolactam and caprolactam grafted nano titanium dioxide activating agent and sodium caprolactam in a mass ratio of 10:240:12, polymerizing under the condition of oil bath at a constant temperature, wherein the oil bath temperature is 185 ℃, the oil bath time is 5 hours, placing the obtained sample in a Soxhlet extractor, and extracting for 22 hours by using methanol to obtain the nano titanium dioxide modified polyamide 6 composite material;

(4) mixing the nano titanium dioxide modified polyamide 6 composite material, formic acid, 10% calcium chloride methanol solution, pore-foaming agent polyvinylpyrrolidone and polyethylene glycol, wherein the mass ratio of the nano titanium dioxide modified polyamide 6 composite material to the pore-foaming agent is 10:3.5, pouring the mixed solution on a glass plate, spreading the mixed solution to form a film, standing the film, drying the film, standing the film in distilled water, and placing the film in a mixed solution of deionized water, glycerol and sodium bisulfite with the volume ratio of 118:24:1 to obtain the nano titanium dioxide modified polyamide 6 composite filter membrane material.

Example 4

(1) Adding toluene, nano titanium dioxide and p-phenylene diisocyanate into a three-neck flask, wherein the mass ratio of the nano titanium dioxide to the p-phenylene diisocyanate is 10:60, uniformly mixing in a nitrogen atmosphere, adding dibutyltin dilaurate, stirring and mixing, wherein the stirring reaction temperature is 70 ℃, and the stirring reaction time is 6 hours, so as to obtain isocyanate functionalized nano titanium dioxide;

(2) adding isocyanate functionalized nano titanium dioxide and caprolactam into a three-neck flask in a mass ratio of 10:65, heating and stirring at 105 ℃, heating and stirring for reaction for 7 hours, centrifuging, washing and drying to obtain caprolactam grafted titanium dioxide;

(3) adding caprolactam and caprolactam grafted titanium dioxide into a three-neck flask, heating at 140 ℃, repeatedly vacuumizing, filling nitrogen, repeating for 5 times, adding sodium caprolactam, caprolactam and caprolactam grafted nano titanium dioxide activating agent and sodium caprolactam in a mass ratio of 10:450:15, polymerizing under the condition of oil bath at constant temperature, wherein the oil bath temperature is 190 ℃, the oil bath time is 6 hours, placing the obtained sample in a Soxhlet extractor, and extracting for 24 hours by using methanol to obtain the nano titanium dioxide modified polyamide 6 composite material;

(4) mixing the nano titanium dioxide modified polyamide 6 composite material, formic acid, 10% calcium chloride methanol solution, pore-foaming agent polyvinylpyrrolidone and polyethylene glycol, wherein the mass ratio of the nano titanium dioxide modified polyamide 6 composite material to the pore-foaming agent is 10:4, pouring the mixed solution on a glass plate, spreading the mixed solution to form a film, standing the film, drying the film, standing the film in distilled water, and placing the film in a mixed solution of deionized water, glycerol and sodium bisulfite with the volume ratio of 118:24:1 to obtain the nano titanium dioxide modified polyamide 6 composite filter membrane material.

Comparative example 1

(1) Adding toluene, nano titanium dioxide and p-phenylene diisocyanate into a three-neck flask, wherein the mass ratio of the nano titanium dioxide to the p-phenylene diisocyanate is 10:35, uniformly mixing in a nitrogen atmosphere, adding dibutyltin dilaurate, stirring and mixing, wherein the stirring reaction temperature is 55 ℃, and the stirring reaction time is 4 hours, so as to obtain isocyanate functionalized nano titanium dioxide;

(2) adding isocyanate functionalized nano titanium dioxide and caprolactam into a three-neck flask in a mass ratio of 10:45, heating and stirring at 95 ℃, reacting for 5 hours, centrifuging, washing and drying to obtain caprolactam grafted titanium dioxide;

(3) adding caprolactam and caprolactam grafted titanium dioxide into a three-neck flask, repeatedly vacuumizing and filling nitrogen at the heating temperature of 125 ℃, repeating for 4 times, then adding sodium caprolactam, caprolactam and caprolactam grafted nano titanium dioxide activating agent and sodium caprolactam in a mass ratio of 10:70:8, polymerizing under the condition of oil bath at constant temperature, wherein the oil bath temperature is 175 ℃, the oil bath time is 5 hours, placing the obtained sample in a Soxhlet extractor, and extracting for 20 hours by using methanol to obtain the nano titanium dioxide modified polyamide 6 composite material;

(4) mixing the nano titanium dioxide modified polyamide 6 composite material, formic acid, 10% calcium chloride methanol solution, pore-foaming agent polyvinylpyrrolidone and polyethylene glycol, wherein the mass ratio of the nano titanium dioxide modified polyamide 6 composite material to the pore-foaming agent is 10:1, pouring the mixed solution on a glass plate, spreading the mixed solution to form a film, standing the film, drying the film, standing the film in distilled water, and placing the film in a mixed solution of deionized water, glycerol and sodium bisulfite with the volume ratio of 118:24:1 to obtain the nano titanium dioxide modified polyamide 6 composite filter membrane material.

Comparative example 2

(1) Adding toluene, nano titanium dioxide and p-phenylene diisocyanate into a three-neck flask, wherein the mass ratio of the nano titanium dioxide to the p-phenylene diisocyanate is 10:75, uniformly mixing in a nitrogen atmosphere, adding dibutyltin dilaurate, stirring and mixing, wherein the stirring reaction temperature is 65 ℃, and the stirring reaction time is 5 hours, so as to obtain isocyanate functionalized nano titanium dioxide;

(2) adding isocyanate functionalized nano titanium dioxide and caprolactam into a three-neck flask in a mass ratio of 10:80, heating and stirring at 100 ℃, reacting for 6 hours, centrifuging, washing and drying to obtain caprolactam grafted titanium dioxide;

(3) adding caprolactam and caprolactam grafted titanium dioxide into a three-neck flask, repeatedly vacuumizing and filling nitrogen at the heating temperature of 135 ℃, repeating for 4 times, then adding sodium caprolactam, caprolactam and caprolactam grafted nano titanium dioxide activating agent and sodium caprolactam in a mass ratio of 10:540:18, polymerizing under the condition of oil bath at a constant temperature, wherein the oil bath temperature is 185 ℃, the oil bath time is 5 hours, placing the obtained sample in a Soxhlet extractor, and extracting for 22 hours by using methanol to obtain the nano titanium dioxide modified polyamide 6 composite material;

(4) mixing the nano titanium dioxide modified polyamide 6 composite material, formic acid, 10% calcium chloride methanol solution, pore-foaming agent polyvinylpyrrolidone and polyethylene glycol, wherein the mass ratio of the nano titanium dioxide modified polyamide 6 composite material to the pore-foaming agent is 10:6, pouring the mixed solution on a glass plate, spreading the mixed solution to form a film, standing the film, drying the film, standing the film in distilled water, and placing the film in a mixed solution of deionized water, glycerol and sodium bisulfite with the volume ratio of 118:24:1 to prepare the nano titanium dioxide modified polyamide 6 composite material.

The method comprises the steps of using a nano titanium dioxide modified polyamide 6 composite filter membrane material with the mass fraction of nano titanium dioxide of 1%, and measuring the water flux of the oily wastewater by using a device made of a filter membrane and an ultrafiltration cup at room temperature and under the pressure of 0.1MPa, wherein the national standard of detection is GB/T34242-2017.

The nano titanium dioxide modified polyamide 6 composite filter membrane material with the mass fraction of 1% of nano titanium dioxide is used, and a HT-3020 universal material tensile testing machine is adopted to perform corresponding tensile tests on different filter membranes.

Different nano titanium dioxide modified polyamide 6 composite filter membrane materials with the mass fraction of 1% of nano titanium dioxide are used for carrying out relevant tests on the removal effect of COD in the oily wastewater.