阅读说明：本技术 一种去除水中磺胺类抗生素的改性超滤膜及制备方法和应用 (Modified ultrafiltration membrane for removing sulfonamide antibiotics in water as well as preparation method and application of modified ultrafiltration membrane ) 是由 贾瑞宝 孙韶华 王明泉 辛晓东 周安然 孙家宁 于 2020-05-28 设计创作，主要内容包括：本发明公开了一种去除水中磺胺类抗生素的改性超滤膜及制备方法和应用,该所述改性超滤膜以聚乙烯吡咯烷酮(PVP)、纳米TiO<Sub>2</Sub>、三氯化铁(FeCl<Sub>3</Sub>)作为添加剂,采用物理共混法对PVDF超滤膜进行改性。在相同的PVDF含量下,PVP、纳米TiO<Sub>2</Sub>和FeCl<Sub>3</Sub>加入能明显增大膜的膜孔数量及其孔径,使其分布更加均匀；在膜中加入TiO<Sub>2</Sub>和FeCl<Sub>3</Sub>可以显著提高PPTFe膜的亲水性和润湿性；膜孔的数量和尺寸增加,膜纯水通量明显提高。本发明制备的改性超滤膜与UV光照的结合去除磺胺嘧啶具有更好的去除效果。本发明制备方法简便,生产成本低。(The invention discloses a modified ultrafiltration membrane for removing sulfonamide antibiotics in water, a preparation method and application thereof 2 Ferric chloride (FeCl) 3 ) As an additive, a physical blending method is adopted to modify the PVDF ultrafiltration membrane. PVP and nano TiO at the same PVDF content 2 And FeCl 3 The number and the pore diameter of the membrane pores can be obviously increased by adding the additive, so that the membrane pores are distributedThe uniformity is better; incorporation of TiO into films 2 And FeCl 3 The hydrophilicity and wettability of the PPTFE film can be obviously improved; the number and the size of the membrane pores are increased, and the pure water flux of the membrane is obviously improved. The modified ultrafiltration membrane prepared by the invention has better removal effect by combining with UV illumination to remove sulfadiazine. The preparation method is simple and convenient, and the production cost is low.)

1. A modified ultrafiltration membrane for removing sulfonamide antibiotics in water is characterized by being prepared from the following components in parts by mass:

the method comprises the following specific steps:

(1) stirring the dried polyvinylidene fluoride and the N, N-dimethylacetamide uniformly at room temperature; then adding polyvinylpyrrolidone and nano TiO₂And ferric chloride (FeCl)₃) Uniformly mixing to obtain a casting solution;

(2) stirring the casting solution in a water bath at constant temperature, and performing ultrasonic oscillation dispersion treatment to reduce nano TiO₂To make the nano TiO agglomerate₂Quickly and uniformly distributed in the casting solution;

(3) standing the casting solution obtained in the step (2) at the temperature of 4 ℃ for more than 24 hours, then casting the casting solution on plate glass of a film scraping machine, and scraping the film by a scraper;

(4) and after film formation, soaking the film in ultrapure water to eliminate the residual casting film liquid in the film, thus obtaining the film.

2. The modified ultrafiltration membrane for removing the sulfonamide antibiotics in the water as claimed in claim 1, which is characterized by being prepared from the following components in parts by mass:

3. the modified ultrafiltration membrane for removing sulfonamide antibiotics in water according to claim 1, wherein the room temperature in step (1) is 20 ℃.

4. The modified ultrafiltration membrane for removing sulfonamide antibiotics in water according to claim 1, wherein the temperature of the water bath in the step (2) is 58-62 ℃; the constant-temperature stirring speed is 100-300 d/min, and the time is 3 h.

5. The modified ultrafiltration membrane for removing sulfonamide antibiotics in water according to claim 1, wherein the time of the ultrasonic oscillation dispersion treatment in the step (2) is 1 h.

6. The modified ultrafiltration membrane for removing sulfonamide antibiotics in water according to claim 1, wherein the speed of scraping the membrane by the scraper in the step (3) is 0.78-0.82 m/min, and the distance between the scraper and the membrane is 190-210 μm.

7. The modified ultrafiltration membrane for removing sulfonamide antibiotics in water of claim 1, wherein the soaking time in step (4) is 7 days.

8. The preparation method of the modified ultrafiltration membrane for removing the sulfonamide antibiotics in the water as claimed in any one of claims 1 to 7, which is characterized by comprising the following specific steps of:

(1) uniformly stirring the dried polyvinylidene fluoride and the N, N-dimethylacetamide at the room temperature of 20 ℃; then adding polyvinylpyrrolidone and nano TiO₂And ferric chloride (FeCl)₃) Uniformly mixing to obtain a casting solution;

(2) stirring the casting solution in a water bath at the temperature of 58-62 ℃ at a constant temperature of 100-300 d/min for 3h, and performing ultrasonic oscillation dispersion treatment for 1h to reduce the nano TiO₂To make the nano TiO agglomerate₂Quickly and uniformly distributed in the casting solution;

(3) standing the casting solution obtained in the step (2) at the temperature of 4 ℃ for more than 24 hours, then casting the casting solution on plate glass of a film scraping machine, scraping the film by a scraper at the speed of 0.78-0.82 m/min, wherein the distance between the scraper and the film is 190-210 mu m;

(4) and after film formation, soaking the membrane in ultrapure water for 7 days, and removing the residual membrane casting solution in the membrane to obtain the membrane.

9. Use of a modified ultrafiltration membrane according to any one of claims 1 to 7 for the removal of a sulfonamide antibiotic from water.

10. The use according to claim 9, wherein the modified ultrafiltration membrane is used in combination with uv light.

Technical Field

The invention relates to a modified ultrafiltration membrane for removing sulfonamide antibiotics in water, a preparation method and application thereof, belonging to the technical field of polymer membrane preparation.

Background

With the development of economic society, the water environment pollution is aggravated, the water quality of a water source is worsened, pollutants in water, particularly organic pollutants, are more and more, and the traditional drinking water treatment method only has an effect on common organic pollutants, has poor removal effect on the two insects and algae and is easy to generate disinfection byproducts. The new generation drinking water purification process can improve the treatment efficiency and the optimization effect, emphasize the generation of nontoxic harmful substances in the process, improve the utilization rate of resources and energy, reduce the pollution load and improve the environmental quality. The ultrafiltration technology can meet the requirements of the purification process of new-generation drinking water and ensure the safety of the drinking water.

The ultrafiltration membrane is a polymer semipermeable membrane which is used for separating polymer colloid or suspended particles with certain size from a solution in the ultrafiltration process, has an asymmetric microporous structure, a thin functional layer and large water permeation flux, and is widely used for the advanced treatment of polluted water sources. The ultrafiltration membrane can retain most suspended substances and colloids in water, but cannot remove soluble small molecular substances, so that the application of the ultrafiltration technology in drinking water treatment is hindered.

The high molecular polymer polyvinylidene fluoride (PVDF) is widely applied due to the characteristics of good thermal stability, mechanical stability, chemical stability and the like, but the intrinsic surface energy is low, the surface hydrophobicity is strong, the interaction with trapped pollutants is easy, the rapid occurrence of membrane pollution and the continuous attenuation of membrane flux are caused, the service life of the membrane is reduced, and the cost of the PVDF membrane in the application process is increased.

At present, the main methods for removing sulfonamide antibiotics in water include biological methods, physical methods and chemical methods. Wherein, the treatment by the biological method can generate drug-resistant bacteria or super bacteria, and if the bacteria infect human, the bacteria can cause serious influence; the physical method mainly comprises an adsorption method and a membrane technology, the adsorption method has higher treatment cost due to high price of an adsorbent, and the single membrane filtration in the membrane technology can reduce the concentration of antibiotics in water to a certain extent but can not completely remove the antibiotics; the chemical method mainly comprises a chlorination method and an advanced oxidation technology, wherein disinfection byproducts generated by the chlorination disinfection method for treating the sulfonamide antibiotics can cause secondary pollution to water bodies.

Disclosure of Invention

The invention aims to provide a modified ultrafiltration membrane for removing sulfonamide antibiotics in water and a preparation method and application thereof aiming at the defects in the prior art₂Ferric chloride (FeCl)₃) As an additive, a physical blending method is adopted to modify the PVDF ultrafiltration membrane. The specific component content and the preparation method comprise the following steps:

a modified ultrafiltration membrane for removing sulfonamide antibiotics in water is prepared from the following components in parts by mass: 25-26.5 parts of polyvinylidene fluoride, 94-99 parts of N, N-dimethylacetamide, 3.0-3.2 parts of polyvinylpyrrolidone and nano TiO₂0.5 to 1.5 parts of ferric chloride and 0.5 to 1.5 parts of ferric chloride.

Preferably, the composition is prepared from the following components in parts by mass: 25 parts of polyvinylidene fluoride, 94 parts of N, N-dimethylacetamide, 3.0 parts of polyvinylpyrrolidone, 21.5 parts of nano TiO21 and 1.0 part of ferric trichloride.

The preparation method comprises the following steps:

(1) stirring the dried polyvinylidene fluoride and the N, N-dimethylacetamide uniformly at room temperature; then adding polyvinylpyrrolidone and nano TiO₂And ferric chloride (FeCl)₃) Uniformly mixing to obtain a casting solution;

(2) stirring the casting solution in a water bath at constant temperature, and performing ultrasonic oscillation dispersion treatment to reduce nano TiO₂To make the nano TiO agglomerate₂Quickly and uniformly distributed in the casting solution;

(3) standing the casting solution obtained in the step (2) at the temperature of 4 ℃ for more than 24 hours, then casting the casting solution on plate glass of a film scraping machine, and scraping the film by a scraper;

(4) and after film formation, soaking the film in ultrapure water to eliminate the residual casting film liquid in the film, thus obtaining the film.

In the preparation method, the room temperature in the step (1) is 20 ℃.

In the preparation method, the temperature of the water bath in the step (2) is 58-62 ℃; the constant-temperature stirring speed is 100-300 d/min, and the time is 3 h; the time of the ultrasonic oscillation dispersion treatment is 1 h.

In the preparation method, the speed of scraping the film by the scraper in the step (3) is 0.78-0.82 m/min, and the distance between the scraper and the film is 190-210 mu m.

In the preparation method, the soaking time in the step (4) is 7 days.

The invention also aims to provide the application of the modified ultrafiltration membrane in removing the sulfonamide antibiotics in water;

when the modified ultrafiltration membrane is used in combination with ultraviolet illumination, the optimal removing effect is achieved.

The invention uses polyvinylpyrrolidone (PVP) and nano TiO₂Ferric chloride (FeCl)₃) As an additive, a PVDF ultrafiltration membrane is modified by adopting a physical blending method, and ferric trichloride can enhance TiO₂By improving the photocatalytic efficiency of TiO₂Electron-hole separation for strengthening, and Fe³⁺The flux of the membrane can be enhanced within a certain range, TiO₂Photocatalyst and Fe³⁺The PVDF ultrafiltration membrane is fixed on the membrane, can reduce loss and enhance recovery rate, and is an effective additive for modifying the PVDF ultrafiltration membrane.

TiO₂The photocatalyst can degrade and remove micro-polluted organic matters and cause the inactivation of microorganisms; by adding TiO₂Improvement of TiO by adsorption of micro-polluted organic matter on particle surface₂The separation of electron holes improves the photocatalytic efficiency;Fe^{3 +}the self-loading technique is to strengthen TiO₂An important means for the photocatalytic effect is to convert Fe³⁺Introduction into TiO₂Within the lattice structure, thereby introducing new charges into the lattice, forming defects or changing the type of lattice, influencing the movement of photogenerated electrons and holes, adjusting their distribution or changing the TiO₂Energy band structure of (1), Fe³⁺Doping can make TiO₂Improved light absorption ability, TiO₂The absorption of the target reactant on the surface is increased, the recombination rate of electrons and holes is reduced, and the TiO is improved₂The photocatalytic performance of (a). On the one hand, TiO₂Photocatalyst and Fe³⁺The membrane is fixed, so that loss can be reduced, and recovery rate can be enhanced; on the other hand, because the film can control pollutants in a centralized way, Fe³⁺Can improve TiO to the maximum extent₂The photocatalytic efficiency of (c).

Has the advantages that:

1. the surface appearance and the composition of the prepared PPTFE modified ultrafiltration membrane can influence the hydrophilicity and the separation performance of the membrane, and the PVP and the nano TiO have the same PVDF content₂And FeCl₃The addition of the additive can obviously increase the number of membrane pores and the pore diameter of the membrane, so that the distribution of the membrane pores is more uniform.

2. The hydrophilicity and wettability of the membrane surface were characterized by the contact angle method. Within a period of 14 seconds, the PPTFe membrane turned from the hydrophilic state to the superhydrophilic state (the contact angle is considered to be in the superhydrophilic state within 30 °) while the contact angles of the other four membranes remained almost unchanged and their initial angles were much larger than PPTFe. These results show that the incorporation of TiO into the film₂And FeCl₃Can obviously improve the hydrophilicity and the wettability of the PPTFE membrane, and the contact angle of 5 membranes is PVDF from large to small>PP>PPFe>PPT>PPTFe。

3. The high-purity water flux shows that the membrane has higher permeability, and the PPTFE membrane has higher pure water flux (219.17 L.m) compared with the traditional ultrafiltration membrane due to the fact that a large number of pores or more hydroxyl groups are formed when nano TiO2 and FeCl3 are added^-2h^-1) And an average pore diameter (60.81nm), the average pore diameter of the PVDF membrane being 8.52nm, the average pore diameter of the PP membrane being 40.68nm,the average pore diameter of the PPT membrane is 53.52nm, the average pore diameter of the PPFe membrane is 46.90nm, and the flux change of the 5 membranes is PPTFE>PPT>PPFe>PP>PVDF。

4. The porosity test result of the membrane shows that the porosity of the PPTFE membrane is obviously greater than that of the traditional membrane, the porosity of the PVDF membrane is 27.01 percent, the porosity of the PPT membrane is 42.09 percent, the porosity of the PPFe membrane is 39.90 percent, the porosity of the PP membrane is 38.01 percent, and the porosity of the PPTFE membrane is 43.02 percent. This shows that with the same amount of PVDF, the PVP and the nano TiO are mixed₂And FeCl₃The number and the size of the membrane pores are increased, and the pure water flux of the membrane is obviously improved at the same time.

5. The preparation method is simple and convenient, and the production cost is low.

Drawings

FIG. 1 is a diagram of a PPTFE modified ultrafiltration membrane prepared in example 1 of the present invention;

FIG. 2 is an SEM image of a PPTFE modified ultrafiltration membrane prepared in example 1 of the present invention;

FIG. 3 is an SEM image of a PVDF-modified ultrafiltration membrane;

FIG. 4 is an SEM image of a PP modified ultrafiltration membrane;

FIG. 5 is an SEM image of a PPT-modified ultrafiltration membrane;

fig. 6 is an SEM image of the PPFe-modified ultrafiltration membrane.

Detailed Description

The invention is further described below with reference to the figures and examples.