Preparation method of titanium suboxide hollow fiber membrane
阅读说明：本技术 一种亚氧化钛中空纤维膜的制备方法 (Preparation method of titanium suboxide hollow fiber membrane ) 是由 范新飞 杨易 潘宗林 宋成文 于 2021-08-30 设计创作，主要内容包括：本发明属于膜分离领域,涉及一种亚氧化钛中空纤维膜的制备方法。本发明选用导电材料亚氧化钛为原材料,通过湿法纺丝方法结合高温煅烧工艺,制备出了亚氧化钛中空纤维膜。亚氧化钛中空纤维膜具有很高的化学稳定性和抗腐蚀性,能克服碳材料、金属材料等导电材料在高电位且有氧存在下易被氧化腐蚀的问题。相较于掺杂硼金刚石、氧化锡、氧化铅等导电膜,成本效益高,绿色环保。该制备方法灵活高效,可调控,亚氧化钛中空纤维膜填充密度大,单位体积面积大,有利于大规模推广应用。(The invention belongs to the field of membrane separation, and relates to a preparation method of a titanium suboxide hollow fiber membrane. The invention selects the conductive material titanium suboxide as the raw material, and prepares the titanium suboxide hollow fiber membrane by combining a wet spinning method with a high-temperature calcination process. The titanium dioxide hollow fiber membrane has high chemical stability and corrosion resistance, and can overcome the problem that conductive materials such as carbon materials, metal materials and the like are easy to be oxidized and corroded under the conditions of high potential and oxygen. Compared with the conductive film doped with boron diamond, tin oxide, lead oxide and the like, the conductive film has high cost benefit and is green and environment-friendly. The preparation method is flexible and efficient, can be regulated and controlled, has large filling density of the titanium suboxide hollow fiber membrane and large unit volume area, and is favorable for large-scale popularization and application.)
1. A method for preparing a titanium suboxide hollow fiber membrane is characterized by comprising the following steps:
(1) and (3) wet spinning: mixing Ti4O7Sequentially adding the high molecular compound into the organic solvent, and uniformly stirring to form a casting solution; selecting coaxial spinning needleThe head takes deionized water or mixed solution of ethanol and deionized water in any proportion as inner layer feeding liquid, casting solution as outer layer feeding liquid, and the inner and outer layer feeding liquids are simultaneously injected into a water condensation bath through an injection pump to obtain a membrane with a hollow fiber structure;
(2) high-temperature calcination: and (3) taking out the membrane obtained in the step (1), airing, calcining at high temperature, naturally cooling, and taking out to obtain the titanium dioxide hollow fiber membrane.
2. The method of claim 1, wherein the Ti in step (1)4O7The average particle diameter is 10nm-50 μm.
3. The method of claim 2, wherein the Ti in step (1)4O7The average particle diameter is 2-10 μm.
4. The method according to claim 1, wherein the titanium dioxide hollow fiber membrane prepared in step (1) has an inner diameter and an outer diameter, and a membrane thickness which are adjustable according to the diameter of the coaxial spinning needle and the liquid supply speed of the inner layer and the outer layer.
5. The method according to claim 1, wherein the polymer compound in step (1) is one or more of polyvinyl alcohol (PVA), polyvinyl butyral (PVB), polyvinylidene fluoride (PVDF), Polysulfone (PSF), polyethersulfone (PESf), Polyacrylonitrile (PAN), Polyetherimide (PEI), Polycarbonate (PC) or Cellulose Acetate (CA), polyvinyl polypyrrolidone (PVPP), and polyvinyl pyrrolidone (PVP).
6. The method according to claim 1, wherein the organic solvent in step (1) is one or more of N, N-Dimethylformamide (DMF), N, N-Dimethylacetamide (DMA), N-methylpyrrolidone (NMP) and Dimethylsulfoxide (DMSO).
7. The method of claim 1, wherein the step (1) is performed in the presence of a catalystTi of (A)4O7The ratio of the Ti to the high molecular compound is 1: 0.2-14O7The concentration range is 10 wt% -60 wt%, and the feeding speed of the inner layer and the outer layer of the coaxial spinning needle is 1: 1-4.
8. The method as claimed in claim 1, wherein the calcination temperature in step (2) is in the range of 800-1600 ℃; the temperature rising speed is 2-10 ℃; the calcination process is carried out in an oxygen-free environment, wherein the oxygen-free environment is vacuum or an argon, nitrogen or hydrogen environment; the calcination time is 1-6 hours.
9. A titanium dioxide hollow fiber membrane prepared by the method of any one of claims 1 to 8.
Technical Field
The invention belongs to the field of membrane separation, and relates to a preparation method of a titanium suboxide hollow fiber membrane.
Background
With the continuous development of urbanization and industrialization, the problems of fresh water demand and water pollution are increasingly serious, and the shortage of water resources becomes a bottleneck for restricting the sustainable development of human beings. Compared with the traditional separation technologies such as filtration, rectification, extraction and the like, the membrane technology is a novel high-efficiency separation technology, and has the characteristics of low energy consumption, high separation efficiency and simplicity in operation. The core of membrane technology is separation membranes, and among them, hollow fiber membranes have the advantages of high packing density, large unit volume area and low cost, and are receiving much attention. Despite the above advantages, the application process is subject to a trade-off between selectivity and permeability, and the problem of membrane fouling needs to be solved. Research shows that the coupled electrochemical water treatment technology can compensate the problem of insufficient treatment capacity of the conventional separation membrane by applying voltage on the separation membrane. However, most hollow fiber membranes are non-conductive membranes, and therefore, it is urgently required to prepare conductive membranes. However, in the process of manufacturing the conductive film, the selection of the conductive material is mainly focused on the carbon nanotube, the metal material. Under the high-potential and aerobic environment, the development and application of the conductive hollow fiber membrane are limited by the characteristics that the carbon nano tube and the metal material are easy to oxidize and corrode, the cost is high, and the large-scale production is difficult.
Disclosure of Invention
The invention aims at the hollow fiber membrane guideThe problems in the selection of electric materials and the market demand, and provides a preparation method of a titanium suboxide hollow fiber membrane. Ti used in the invention4O7Good chemical stability, corrosion resistance, strong conductivity, green and environmental protection. In addition, the preparation method provided by the invention is simple, flexible and controllable, and is convenient for large-scale production and application.
In one aspect, the present invention provides a Ti4O7The preparation method of the hollow fiber membrane comprises the following steps:
(1) and (3) wet spinning: mixing Ti4O7And sequentially adding the high molecular compound into the organic solvent, and uniformly stirring to form a casting solution. Selecting a coaxial spinning needle, taking deionized water or a mixed solution of ethanol and deionized water in any proportion as an inner layer feeding solution, taking a casting solution as an outer layer feeding solution, and simultaneously injecting the inner layer feeding solution and the outer layer feeding solution into a water condensation bath through an injection pump to obtain the membrane with the hollow fiber structure.
(2) High-temperature calcination: and (3) taking out the membrane obtained in the step (1), airing, calcining at high temperature, naturally cooling, and taking out to obtain the titanium dioxide hollow fiber membrane.
In the present invention, the Ti is4O7Is commercially available and has an average particle diameter of 10nm to 50 μm, preferably 2 to 10 μm.
In the present invention, the polymer compound may be one or more of polyvinyl alcohol (PVA), polyvinyl butyral (PVB), polyvinylidene fluoride (PVDF), Polysulfone (PSF), polyethersulfone (PESf), Polyacrylonitrile (PAN), Polyetherimide (PEI), Polycarbonate (PC) or Cellulose Acetate (CA), polyvinyl polypyrrolidone (PVPP), and polyvinyl pyrrolidone (PVP).
In the present invention, the organic solvent may be one or more of N, N-Dimethylformamide (DMF), N-Dimethylacetamide (DMA), N-methylpyrrolidone (NMP), and Dimethylsulfoxide (DMSO).
In the present invention, the Ti is4O7The ratio of the Ti to the high molecular compound is 1: 0.2-14O7The concentration range is 10 wt% -60 wt%, and the feeding speed of the inner layer and the outer layer of the coaxial spinning needle is 1: 1-4.
In the invention, the calcining temperature range is 800-1600 ℃; the temperature rising speed is 2-10 ℃; the calcination process is performed in an oxygen-free environment and can be performed in a vacuum environment or an argon, nitrogen or hydrogen environment; the calcination time is 1-6 hours.
In the invention, the outer diameter and the thickness of the titanium suboxide hollow fiber membrane can be flexibly adjusted according to the diameter of the coaxial spinning needle head and the liquid supply speed of the inner layer and the outer layer.
In another aspect, the present invention provides a titanium suboxide hollow fiber membrane prepared by the above method.
The invention has the following characteristics:
1. the research of the invention discovers that Ti4O7When the material is used for preparing a hollow fiber membrane as a Magneli phase titanium oxide substance, compared with a common conductive material, the material has high chemical stability and corrosion resistance, is very stable in strong acid and strong alkali environments, and can make up the defect that conductive materials such as carbon materials and metal materials are easy to oxidize and corrode under the conditions of high potential and oxygen.
2. Ti in comparison to boron-doped diamond (BDD) with good electrochemical stability4O7More cost-effective than tin oxide (SnO)2) And lead oxide (PbO)2) Is more environment-friendly. Ti4O7The specific gravity is small, the product is light, the compatibility with organic matters is high, and the product can be mixed with various plastics for molding.
3. Compared with the traditional flat membrane, the hollow fiber structure has the advantages of high filling density, large unit volume area and low cost, and is favorable for large-scale popularization and application.
4. The cyclic voltammetry, linear voltammetry scanning results and pollutant treatment results can all prove that the novel hollow fiber membrane prepared by the invention has good stability and application prospect.
Drawings
FIG. 1 is Ti in example 14O7A physical photograph of the hollow fiber membrane;
FIG. 2 shows Ti in example 14O7Surface electron microscope photographs of the hollow fiber membranes;
FIG. 3 shows Ti in example 14O7A section electron microscope photograph of the hollow fiber membrane;
FIG. 4 shows Ti in example 14O7The section of the hollow fiber membrane was locally magnified by electron microscopy.
Detailed Description
The following non-limiting examples are presented to enable those of ordinary skill in the art to more fully understand the present invention and are not intended to limit the invention in any way.
The test methods described in the following examples are all conventional methods unless otherwise specified; the reagents and materials are commercially available, unless otherwise specified.
Example 1
The first step is as follows: titanium oxide having an average particle size of 5 μm was used as a starting material, and 3.0g of titanium oxide and 1.5g of polyvinyl butyral were sequentially added to a 6g N, N-dimethylformamide solution, and the mixture was sealed and stirred for 8 hours to obtain a casting solution. The hollow fiber membrane is prepared by utilizing a coaxial wet spinning technology, and a spinning needle head is immersed into deionized water. Feeding liquid by using a medical injection pump, wherein the inner layer feeding liquid is deionized water, and the liquid feeding speed is 10 ml/h; the outer layer feeding liquid is spinning liquid, and the liquid supply speed is 20 ml/L. And soaking the obtained film in deionized water, fully curing, taking out, straightening and airing.
The second step is that: and (3) sintering the hollow fiber membrane obtained in the step (1) in a tube furnace. And (3) heating at the constant temperature of 1200 ℃ for 2h under the condition that the sintering atmosphere is argon and the heating rate is 5 ℃/min, cooling and taking out to obtain the titanium suboxide hollow fiber membrane.
The experimental results are as follows: the scanning electron microscope result shows that the prepared titanium dioxide hollow fiber membrane has no obvious defects and good conductivity. The outer diameter was 780 μm and the inner diameter was 410. mu.m. The result of cyclic voltammetric scanning shows that the concentration of NaClO is 100mM4With 5mM K4Fe(CN)6In the mixed solution, the scanning pattern has no obvious change after 200 cycles, which indicates that the chemical property is stable. With Ti4O7The hollow fiber membrane is used as an anode, the titanium mesh is used as a cathode, and 10mM sodium perchlorate (NaClO) is used4) The electrolyte is 10ppm rhodamine b solution, the treatment rate is 99.37 percent under the voltage of 3V, and the continuous transportation is realizedAfter 72 hours, the removal rate is still maintained at about 99.0 percent; after long-time operation, the high removal rate can be still maintained, and the fact that the catalyst is not easy to corrode and oxidize in the presence of high-potential oxygen is proved to have good stability. The removal rate of the phenol solution of 10ppm was 96.01%.
Example 2
The first step is as follows: titanium dioxide with the average particle size of 2 mu m is taken as a raw material, 1.0g of titanium dioxide and 0.5g of polyvinyl alcohol are sequentially added into a 6g N N-dimethylformamide solution, and the mixture is sealed and stirred for 8 hours to obtain a casting solution. The hollow fiber membrane is prepared by utilizing a coaxial wet spinning technology, and a spinning needle head is immersed into deionized water. Feeding liquid by using a medical injection pump, wherein the inner layer feeding liquid is deionized water, and the liquid feeding speed is 4 ml/h; outer layer feeding
The solution is spinning solution, and the liquid supply speed is 8 ml/L. And soaking the obtained film in deionized water, fully curing, taking out, straightening and airing.
The second step is that: and (3) sintering the hollow fiber membrane obtained in the step (1) in a tube furnace. And (3) carrying out constant temperature heating at 1250 ℃ for 6h under the condition that the sintering atmosphere is argon and the heating rate is 5 ℃/min, cooling and taking out to obtain the titanium suboxide hollow fiber membrane.
The experimental results are as follows: the scanning electron microscope result shows that the prepared titanium dioxide hollow fiber membrane has no obvious defects, the outer diameter is 562 mu m, and the inner diameter is 321 mu m. The scanning result of linear sweep voltammetry shows that the hollow fiber membrane is 0.5mg/L H2SO4The oxygen evolution potential in the solution is about 2.5V vs. SCE, which is beneficial to the degradation of pollutants. Close to BDD anode (2.3-2.7V vs. SCE), higher than SnO2Electrode (1.9V vs. SCE), IrO2Electrode (1.6V vs. SCE), PbO2Electrodes (1.9V vs. sce) and platinum electrodes (1.3-1.6V vs. sce); the higher the oxygen evolution potential is, the more difficult the oxygen evolution side reaction is, the higher the current efficiency of the electrochemical oxidation of organic matters is, and the more favorable the degradation of pollutants is. With Ti4O7The hollow fiber membrane is used as an anode, the titanium mesh is used as a cathode, and 10mM NaClO is used4The electrolyte is prepared by treating 10ppm rhodamine b solution to 98.53 percent under the voltage of 3V; the removal rate of the phenol solution of 10ppm was 97.1%.
Example 3
The first step is as follows: titanium oxide having an average particle size of 5 μm was used as a starting material, and 1.0g of titanium oxide and 0.8g of polyvinyl butyral were sequentially added to a 6g N, N-dimethylformamide solution, and the mixture was sealed and stirred for 8 hours to obtain a casting solution. The hollow fiber membrane is prepared by utilizing a coaxial wet spinning technology, and a spinning needle head is immersed into deionized water. Feeding liquid by using a medical injection pump, wherein the inner layer feeding liquid is deionized water, and the liquid feeding speed is 4 ml/h; the outer layer feeding liquid is spinning liquid, and the liquid supply speed is 8 ml/L. And soaking the obtained film in deionized water, fully curing, taking out, straightening and airing.
The second step is that: and (3) sintering the hollow fiber membrane obtained in the step (1) in a tube furnace. And (3) heating at the constant temperature of 1200 ℃ for 6h at the temperature rising speed of 5 ℃/min under the argon sintering atmosphere, cooling, and taking out to obtain the titanium suboxide hollow fiber membrane.
The experimental results are as follows: the scanning electron microscope result shows that the prepared titanium dioxide hollow fiber membrane has no obvious defects, the outer diameter is 800 μm, and the inner diameter is 560 μm. With Ti4O7The hollow fiber membrane is used as an anode, the titanium mesh is used as a cathode, and 10mM NaClO is used4As electrolyte, under 3V voltage, the treatment of 10ppm methyl orange solution is 98.74%; the removal rate of the phenol solution of 10ppm was 93.97%.
Example 4
The first step is as follows: titanium oxide having an average particle size of 5 μm was used as a starting material, and 1.0g of titanium oxide and 0.5g of polyvinyl butyral were sequentially added to a 6g N, N-dimethylformamide solution, and the mixture was sealed and stirred for 8 hours to obtain a casting solution. The hollow fiber membrane is prepared by utilizing a coaxial wet spinning technology, and a spinning needle head is immersed into deionized water. Feeding liquid by using a medical injection pump, wherein the inner layer feeding liquid is deionized water, and the liquid feeding speed is 4 ml/h; the outer layer feeding liquid is spinning liquid, and the liquid supply speed is 8 ml/L. And soaking the obtained film in deionized water, fully curing, taking out, straightening and airing.
The second step is that: and (3) sintering the hollow fiber membrane obtained in the step (1) in a tube furnace. And (3) heating at the constant temperature of 1200 ℃ for 6h at the temperature rising speed of 5 ℃/min under the argon sintering atmosphere, cooling, and taking out to obtain the titanium suboxide hollow fiber membrane.
The experimental results are as follows: the scanning electron microscope result shows that the prepared titanium dioxide hollow fiber membrane has no obvious defects, the outer diameter is 780 mu m, and the inner diameter is 500 mu m. With Ti4O7The hollow fiber membrane is used as an anode, the titanium mesh is used as a cathode, and 10mM NaClO is used4As electrolyte, under 3V voltage, 10ppm tetracycline solution to 99.16%; the removal rate of the amoxicillin with 10ppm is 94.78%.
Example 5
The first step is as follows: titanium dioxide with the average particle size of 2 mu m is taken as a raw material, 1.0g of titanium dioxide and 0.8g of polyacrylonitrile are sequentially added into a 6g N N-dimethylformamide solution, and the mixture is sealed and stirred for 8 hours to obtain a casting solution. The hollow fiber membrane is prepared by utilizing a coaxial wet spinning technology, and a spinning needle head is immersed into deionized water. Feeding liquid by using a medical injection pump, wherein the inner layer feeding liquid is deionized water, and the liquid feeding speed is 4 ml/h; the outer layer feeding liquid is spinning liquid, and the liquid supply speed is 8 ml/L. And soaking the obtained film in deionized water, fully curing, taking out, straightening and airing.
The second step is that: and (3) sintering the hollow fiber membrane obtained in the step (1) in a tube furnace. And (3) carrying out constant temperature heating at 1250 ℃ for 6h under the condition that the sintering atmosphere is argon and the heating rate is 5 ℃/min, cooling and taking out to obtain the titanium suboxide hollow fiber membrane.
The experimental results are as follows: the scanning electron microscope result shows that the prepared titanium dioxide hollow fiber membrane has no obvious defects, the outer diameter is 648 μm, and the inner diameter is 387 μm. With Ti4O7The hollow fiber membrane is used as an anode, the titanium mesh is used as a cathode, and 10mM NaClO is used4As electrolyte, under 3V voltage, the treatment of 10ppm nitrophenol solution is 99.06%; the removal rate of the benzoquinone solution at 10ppm was 95.34%.
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