CN111085111A - Rare earth complex acid salt antibacterial agent, antibacterial modified hollow fiber membrane and preparation method thereof - Google Patents
Rare earth complex acid salt antibacterial agent, antibacterial modified hollow fiber membrane and preparation method thereof Download PDFInfo
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- CN111085111A CN111085111A CN201911407606.6A CN201911407606A CN111085111A CN 111085111 A CN111085111 A CN 111085111A CN 201911407606 A CN201911407606 A CN 201911407606A CN 111085111 A CN111085111 A CN 111085111A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/02—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor characterised by their properties
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
- B01D67/0081—After-treatment of organic or inorganic membranes
- B01D67/0093—Chemical modification
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/08—Hollow fibre membranes
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2325/00—Details relating to properties of membranes
- B01D2325/48—Antimicrobial properties
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A20/00—Water conservation; Efficient water supply; Efficient water use
- Y02A20/124—Water desalination
- Y02A20/131—Reverse-osmosis
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Abstract
The invention belongs to the field of membrane preparation, and particularly relates to a rare earth complex acid salt antibacterial agent, an antibacterial modified hollow fiber membrane and a preparation method thereof. The rare earth complex acid salt antibacterial agent is prepared by slowly adding rare earth solution citric acid into tungstate citric acid solution, adding ethylene glycol simultaneously, and heating and continuously stirring the mixed solution to form sol; transferring the obtained sol to an air blast drying chamber to obtain a tan gel, and putting the gel into a muffle furnace for heat treatment to obtain the tungstate antibacterial agent nano powder. The rare earth complex acid salt antibacterial agent is introduced and can be directly used as a coupling agent, the condition that a high polymer material and rare earth elements have unique electronic layer structures is improved, and filled outermost layer electrons and secondary outer layer electrons are easy to lose to form rare earth ions with different valence states. The rare earth has active coordination, can act with bacterial cell wall, cytoplasmic membrane and intracellular DNA, and has the function of inhibiting the proliferation and growth of bacteria, so that the membrane has the antibacterial function.
Description
Technical Field
The invention belongs to the field of membrane preparation, and particularly relates to a rare earth complex acid salt antibacterial agent, an antibacterial modified hollow fiber membrane and a preparation method thereof.
Background
Membrane technology is a chemical separation technology that has grown since the end of the last century. Since the last 60 s, membrane separation technology has entered the industrial field and has been widely used. However, in many fields, the elbow is inevitably caught by membrane pollution caused by easy adsorption of protein, bacteria and microorganisms on the membrane surface, so that the performance of the membrane is continuously reduced in the using process, the using efficiency is low, and the service life of the membrane can be directly influenced more seriously. Therefore, it is very important to find a process capable of effectively improving the antibacterial property of the membrane.
In the patent with publication number CN108786495, an antibacterial method of a graphene oxide modified hollow fiber membrane is introduced, but the preparation of graphene oxide is divided into two steps of preparation of graphene oxide and stripping of graphene oxide, and the preparation process is complicated. Meanwhile, high-concentration strong acid and toxic gas are used in the process of preparing the graphene oxide, so that the danger is high.
Disclosure of Invention
The invention aims to provide an antibacterial modified hollow fiber membrane and a preparation method thereof.
In order to achieve the purpose, the invention adopts the following technical scheme:
the rare earth complex acid salt antibacterial agent is characterized by being prepared by the following method:
1) dissolving soluble rare earth salt in deionized water to form a rare earth solution, dissolving ammonium paratungstate and alkali metal salt in deionized water to form an alkali tungstate solution, and dissolving citric acid ion in water to form a citric acid solution;
2) adding half of the citric acid aqueous solution into the rare earth solution, adding the other half of the citric acid aqueous solution into the tungstate alkali metal solution, and respectively stirring to ensure that metal cations and citric acid form a stable complex;
3) slowly adding rare earth solution citric acid into tungstate citric acid solution, simultaneously adding ethylene glycol, and then heating and continuously stirring the mixed solution to form sol; in the step, except that rare earth ions are fully mixed with tungstate radicals and alkali metal ions in an atomic layer manner, two hydroxyl groups of ethylene glycol are subjected to esterification reaction with citric acid, so that the whole solution system is changed into sol with a stable network structure;
4) transferring the obtained sol to an air blast drying chamber to obtain a tan gel, and putting the gel into a muffle furnace to carry out heat treatment at 500-800 ℃ for 5 hours to obtain tungstate antibacterial agent nano powder.
An antibacterial modified hollow fiber membrane comprises the following components in parts by mass: 13-25 parts of polymer, 45-60 parts of film forming solvent, 17-38 parts of pore-forming agent and 1-5.3 parts of rare earth complex acid salt antibacterial agent.
The rare earth element in the rare earth salt is one of La, Gd, Y, Ce, Nd, Eu, Pr, Sm, Tn, Dy, Ho, Er, Tm, Yo and Lu; the alkali metal salt is soluble salt of Li, Na, K, Ca, Sr and Ba.
The polymer is any one of polyvinylidene fluoride, polysulfone, polyacrylonitrile, polyvinyl chloride and polyether sulfone; the film forming solvent is any one or a combination of several of dimethylformamide, dimethylacetamide, N-methylpyrrolidone or dimethyl sulfoxide according to any proportion; the pore-foaming agent is any one or combination of several of polyvinylpyrrolidone, ethanol, ethylene glycol and diethylene glycol according to any proportion.
The invention also comprises a method for preparing the antibacterial modified hollow fiber membrane, which is characterized by comprising the following steps:
1) preparing a casting solution: fully dissolving the rare earth composite salt antibacterial agent nano powder obtained in the step 1) in a film forming solvent, mixing with a polymer and a pore-forming agent, stirring and dissolving at 60-80 ℃, and removing bubbles after uniformly mixing to obtain a required casting solution;
2) and extruding the membrane casting solution through a spinneret plate, putting the membrane casting solution into a coagulating bath at the temperature of 20-70 ℃, and obtaining the hollow fiber membrane nascent fiber after the gelation is finished.
The coagulation bath comprises an inner coagulation bath and an outer coagulation bath, the inner coagulation bath is pure water, and the outer coagulation bath is a mixed solution of water and dimethylformamide, dimethylacetamide, N-methylpyrrolidone or dimethyl sulfoxide; the percentage content of water in the mixed solution is 30-80%
Compared with the prior art, the invention has the beneficial effects that:
the rare earth complex acid salt antibacterial agent is introduced and can be directly used as a coupling agent, the condition that a high polymer material and rare earth elements have unique electronic layer structures is improved, and filled outermost layer electrons and secondary outer layer electrons are easy to lose to form rare earth ions with different valence states. The rare earth has active coordination, can act with bacterial cell wall, cytoplasmic membrane and intracellular DNA, and has the function of inhibiting the proliferation and growth of bacteria, so that the membrane has the antibacterial function.
The common hollow fiber membrane prepared under the same experimental condition and the rare earth modified hollow fiber membrane simultaneously simulate the practical application environment, the membrane strip is soaked in the same amount of tap water, the membrane strip is placed at room temperature for 7 days, and then the surface flora condition is observed by using an electron microscope. The rare earth modified hollow fiber membrane has no obvious change on the surface before and after culture, and the common hollow fiber membrane has punctate mildew spots after culture compared with the prior culture, and a plurality of floras can be clearly seen. The comparison between the cultured common hollow fiber membrane and the rare earth modified hollow fiber membrane shows that the addition of the rare earth has obvious improvement effect on the antibacterial property of the membrane
Meanwhile, the rare earth complex acid salt antibacterial agent is prepared, and the obtained product has the advantages of small particle size, uniform particle size, high purity and the like, and meanwhile, the method is simple, safe, easy to control and mild in reaction conditions.
Drawings
FIG. 1-2 is a schematic view of a rare earth-modified hollow fiber membrane before and after culture;
FIGS. 3 to 4 are schematic views of a general hollow fiber membrane before and after culture.
Detailed Description
In order to make the technical solutions of the present invention better understood by those skilled in the art, the present invention will be further described in detail with reference to the accompanying drawings and preferred embodiments.
Example 1: the method for preparing the antibacterial modified hollow fiber membrane comprises the following steps:
1) preparing rare earth complex acid salt: 1) dissolving 2mmol of La (N03) 3. xH20 in 20mL of deionized water to form a rare earth solution, dissolving 0.4mmol of ammonium paratungstate and 1mmol of potassium carbonate in 20mL of deionized water to form an alkali tungstate solution, and dissolving 20mmol of citric acid in 20mL of deionized water to form a citric acid solution; 2) adding half of the citric acid aqueous solution into the rare earth solution, adding the other half of the citric acid aqueous solution into the tungstate alkali metal solution, and respectively stirring for 10 minutes to enable metal cations and citric acid to form a stable complex; 3) the citric acid rare earth solution was slowly added to the citric acid alkali metal tungstate while 2mL of ethylene glycol was added, and then the mixed solution was heated to 80 ℃ and continuously stirred for 1 hour. In this step, except that rare earth ions are fully mixed with tungstate radical and potassium ion in atom level, two hydroxyl groups of ethylene glycol are esterified with citric acid, so that the whole solution system becomes sol with a stable network structure. 4) And transferring the obtained sol to an air-blast constant-temperature drying oven, heating for 24h at 80 ℃, then performing vacuum drying to obtain a tan gel, and putting the gel into a muffle furnace to perform heat treatment for 5 h at a selected temperature (500 ℃) to finally obtain tungstate antibacterial agent nano powder.
2) Preparing a casting solution: according to the mass fraction, 5.3% of tungstate antibacterial agent powder is fully dissolved in 45% of dimethylformamide, then mixed with 13% of polyether sulfone, 28% of polyvinylpyrrolidone, 5% of ethylene glycol and 3.7% of ethanol, stirred and dissolved at 60 ℃, and after uniform mixing, bubbles are removed, and the required casting solution is obtained.
3) And extruding the membrane casting solution through a spinneret plate, putting the membrane casting solution into a coagulating bath, and gelling for a certain time to obtain the required hollow fiber membrane. Wherein the inner coagulation bath is pure water with the temperature of 30 ℃, the outer coagulation bath is a mixed solution of water and dimethylformamide, the temperature is 60 ℃, and the percentage content of the water in the mixed coagulation bath is 50%. The resulting hollow fiber membranes were tested for pure water flux and attenuation rate. The decay rate is the percentage of the water flux decay of the membrane due to contamination, and the tap water of the pipe network is used for the decay rate test. The pure water flux is 216.72L/square meter.h, and the attenuation rate is 23.57 percent.
Comparative example 1: comparative example 1 differs from example 1 only in that the tungstate antimicrobial powder was not added; the resulting hollow fiber membranes were tested for pure water flux and attenuation rate. The pure water flux is 198.80L/square meter.h, and the attenuation rate is 31.77%. FIG. 1-2 is a schematic view of a rare earth-modified hollow fiber membrane before and after culture; FIGS. 3 to 4 are schematic views of a general hollow fiber membrane before and after culture.
Example 2: the tungstate antimicrobial powder was the same as in example 1; according to the mass fraction, 3% of tungstate antibacterial agent powder is fully dissolved in 55% of a mixed solution of dimethylformamide and dimethylacetamide (the ratio is 2:1), then the tungstate antibacterial agent powder is mixed with 20% of polyvinylidene fluoride, 12% of polyvinylpyrrolidone and 10% of ethylene glycol, the mixture is stirred and dissolved at 80 ℃, and after the mixture is uniformly mixed, bubbles are removed, and the required casting solution is obtained. And extruding the membrane casting solution through a spinneret plate, putting the membrane casting solution into a coagulating bath, and gelling for a certain time to obtain the required hollow fiber membrane. Wherein the inner coagulation bath is pure water at 40 ℃, the outer coagulation bath is a mixed solution (the ratio is 2:1) of water, dimethyl formamide and dimethyl acetamide, the temperature is 40 ℃, and the percentage content of water in the mixed coagulation bath is 40%. The pure water flux is 176.91L/square meter.h, and the attenuation rate is 18.48 percent.
Comparative example 2: comparative example 2 differs from example 2 only in that the tungstate antimicrobial powder was not added; the resulting hollow fiber membranes were tested for pure water flux and attenuation rate. The pure water flux is 121.63L/square meter.h, and the attenuation rate is 26.14 percent.
Example 3: according to the mass fraction, 1% of tungstate antibacterial agent powder is fully dissolved in 60% of dimethyl sulfoxide and N-methylpyrrolidone mixed solution (the ratio is 2:1), then mixed with 25% of polyacrylonitrile, 10% of ethanol and 4% of diethylene glycol, stirred and dissolved at 70 ℃, and after uniform mixing, bubbles are removed, and the required casting solution is obtained. And extruding the membrane casting solution through a spinneret plate, putting the membrane casting solution into a coagulating bath, and gelling for a certain time to obtain the required hollow fiber membrane. Wherein the inner coagulation bath is pure water with the temperature of 50 ℃, the outer coagulation bath is a mixed solution (the ratio is 2:1) of water, dimethyl sulfoxide and N-methyl pyrrolidone, the temperature is 30 ℃, and the percentage content of the water in the mixed coagulation bath is 30%. The pure water flux is 137.32L/square meter.h, and the attenuation rate is 20.08 percent.
Comparative example 3: comparative example 3 differs from example 3 only in that the tungstate antimicrobial powder was not added; the resulting hollow fiber membranes were tested for pure water flux and attenuation rate. The pure water flux is 109.90L/square meter.h, and the attenuation rate is 22.49 percent.
The above description is only a preferred embodiment of the present invention, and for those skilled in the art, the present invention should not be limited by the description of the present invention, which should be interpreted as a limitation.
Claims (6)
1. The rare earth complex acid salt antibacterial agent is characterized by being prepared by the following method:
1) dissolving soluble rare earth salt in deionized water to form a rare earth solution, dissolving ammonium paratungstate and alkali metal salt in deionized water to form an alkali tungstate solution, and dissolving citric acid ion in water to form a citric acid solution;
2) adding half of the citric acid aqueous solution into the rare earth solution, adding the other half of the citric acid aqueous solution into the tungstate alkali metal solution, and respectively stirring to ensure that metal cations and citric acid form a stable complex;
3) slowly adding rare earth solution citric acid into tungstate citric acid solution, simultaneously adding ethylene glycol, and then heating and continuously stirring the mixed solution to form sol;
4) transferring the obtained sol to an air blast drying chamber to obtain a tan gel, and putting the gel into a muffle furnace to carry out heat treatment at 500-800 ℃ for 5 hours to obtain tungstate antibacterial agent nano powder.
2. An antibacterial modified hollow fiber membrane is characterized by comprising the following components in parts by mass: 13-25 parts of polymer, 45-60 parts of film forming solvent, 17-38 parts of pore-forming agent and 1-5.3 parts of rare earth complex acid salt antibacterial agent prepared according to claim 1.
3. The antibacterial modified hollow fiber membrane of claim 2, wherein the rare earth element in the rare earth salt is one of La, Gd, Y, Ce, Nd, Eu, Pr, Sm, Tn, Dy, Ho, Er, Tm, Yo and Lu; the alkali metal salt is soluble salt of Li, Na, K, Ca, Sr and Ba.
4. The antibacterial modified hollow fiber membrane according to claim 2, wherein the polymer is any one of polyvinylidene fluoride, polysulfone, polyacrylonitrile, polyvinyl chloride and polyethersulfone; the film forming solvent is any one or a combination of several of dimethylformamide, dimethylacetamide, N-methylpyrrolidone or dimethyl sulfoxide according to any proportion; the pore-foaming agent is any one or combination of several of polyvinylpyrrolidone, ethanol, ethylene glycol and diethylene glycol according to any proportion.
5. A method of making an antibacterial modified hollow fibre membrane of any of claims 2 to 4, comprising the steps of:
1) preparing a casting solution: fully dissolving rare earth complex salt antibacterial agent nano powder in a film forming solvent, mixing with a polymer and a pore-forming agent, stirring and dissolving at 60-80 ℃, and removing bubbles after uniformly mixing to obtain a required film casting solution;
2) and extruding the membrane casting solution through a spinneret plate, putting the membrane casting solution into a coagulating bath at the temperature of 20-70 ℃, and obtaining the hollow fiber membrane nascent fiber after the gelation is finished.
6. The method of claim 5, wherein the coagulation bath comprises an inner coagulation bath and an outer coagulation bath, the inner coagulation bath is pure water, and the outer coagulation bath is a mixture of water and dimethylformamide, dimethylacetamide, N-methylpyrrolidone, or dimethylsulfoxide; the percentage content of water in the mixed solution is 30-80%.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2021237381A1 (en) * | 2020-05-23 | 2021-12-02 | 海门茂发美术图案设计有限公司 | Method for preparing rare earth-modified polyethersulfone ultrafiltration membrane |
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