An antibacterial separation membrane uniformly loaded with metal nanoparticles and preparation method thereof

Abstract

The present invention relates to the technical field of novel separation membrane materials, and specifically discloses an antibacterial separation membrane uniformly loaded with metal nanoparticles and a preparation method thereof, wherein the preparation method comprises the following steps: S1, preparing a separation membrane one with uniform pore size; S2, preparing a metal salt solution; S3, immersing the prepared separation membrane one in the prepared metal salt solution to obtain a separation membrane two that adsorbs the metal salt solution; S4, preparing a reducing solution; S5, immersing the prepared separation membrane two in the prepared reducing solution to obtain a separation membrane three loaded with metal nanoparticles. The present invention adopts an antibacterial separation membrane uniformly loaded with metal nanoparticles and a preparation method thereof, and fixes a metal nanoparticle antibacterial agent in a separation membrane with uniform pore distribution. The prepared antibacterial membrane can significantly improve the contact between the antibacterial agent and bacteria and improve the sterilization performance on the one hand, and can also improve the uniformity and stability of the antibacterial agent loading on the other hand.

Description

Technical Field

[0001] The invention relates to the technical field of novel separation membrane materials, and in particular to an antibacterial separation membrane uniformly loaded with metal nanoparticles and a preparation method thereof. Background Art

[0002] In the membrane water treatment process, bacteria, fungi and other microorganisms in the water body adsorb and reproduce on the membrane surface, which will cause serious membrane pollution, affect the permeability and separation efficiency of the membrane, and may also have an adverse effect on the effluent water quality, increasing the difficulty and cost of subsequent treatment. Therefore, it is very important to prepare a separation membrane with antibacterial properties.

[0003] Surface modification is a common method for preparing antibacterial separation membranes. A layer of substances with antibacterial activity, such as silver nanoparticles, quaternary ammonium salts, chitosan, etc., is coated on the membrane surface to achieve antibacterial effects by destroying bacterial cell walls or inhibiting their metabolic activities. Or antibacterial groups are grafted onto the surface of membrane materials by chemical or physical methods to form a stable antibacterial layer, which can improve the durability of the antibacterial effect. However, the loss of antibacterial agents is inevitable. On the one hand, it significantly reduces the antibacterial properties of the membrane, and on the other hand, the escape of antibacterial agents will also cause secondary pollution to the water body. The blending method is to directly add additives with antibacterial functions (such as antibacterial agents, nanoparticles, etc.) during the preparation of membrane materials to make them evenly dispersed in the membrane matrix. This method is simple and easy, but it may have a certain impact on the dispersibility of antibacterial agents and the performance of membranes. Therefore, it is urgent to seek a method for preparing separation membranes with high antibacterial efficiency and stable loading.

[0004] In recent years, various methods for preparing porous membranes have been developed, such as template method, phase conversion method, soft lithography method and breath map method. Inverse opal (IO) is a typical photonic crystal, showing a highly ordered, three-dimensionally connected microporous structure, which is widely used in medicine and catalysis. Some studies have prepared microfiltration membranes with IO-like structures by template method. First, the polymer seed colloidal microspheres are regularly arranged into crystals, and the IO-like microfiltration membrane is obtained by sacrificing the colloidal microsphere template, which shows good separation performance and anti-fouling performance.

[0005] On this basis, the antimicrobial agent is fixed in the pores of the IO-like uniform porous separation membrane through in situ synthesis. On the one hand, it can improve the stability of the antimicrobial agent loading and avoid the agglomeration or escape of the nano-antimicrobial agent. On the other hand, it can increase the contact between the antimicrobial agent and bacteria, etc., and improve the antibacterial performance. It has certain research and application potential. Summary of the invention

[0006] The purpose of the present invention is to provide an antibacterial separation membrane uniformly loaded with metal nanoparticles and a preparation method thereof, wherein the metal nanoparticle antibacterial agent is fixed in a separation membrane with uniform pore distribution. The obtained antibacterial membrane can, on the one hand, significantly improve the contact between the antibacterial agent and bacteria and improve the sterilization performance; on the other hand, it can improve the uniformity and stability of the antibacterial agent loading.

[0007] To achieve the above object, the present invention provides a method for preparing an antibacterial separation membrane uniformly loaded with metal nanoparticles, comprising the following steps:

[0008] S1, preparing a separation membrane with uniform pore size;

[0009] S2, preparing a metal salt solution;

[0010] S3, immersing the separation membrane 1 prepared in step S1 in the metal salt solution prepared in step S2 to obtain a separation membrane 2 that adsorbs the metal salt solution;

[0011] S4, preparing a reducing solution;

[0012] S5. Immerse the separation membrane 2 prepared in step S3 in the reducing solution prepared in step S4 to obtain the separation membrane 3 loaded with metal nanoparticles.

[0013] Preferably, in step S1, a sacrificial template method is used to prepare the separation membrane 1, and the pore structure of the separation membrane 1 is spherical holes, the pore structure is evenly distributed, and the pore structure size is 100-800nm.

[0014] Preferably, in step S1, the specific steps of preparing the separation membrane 1 are as follows:

[0015] The silica microspheres are dispersed in an organic solvent to obtain a silica microsphere dispersion, 8-15wt% of a polyvinylidene fluoride polymer is added to the silica microsphere dispersion, the mixture is evenly mixed to obtain a casting solution, the casting solution is poured on a glass plate, and the mixture is cured in a constant temperature oven at 80°C until the organic solvent evaporates to obtain a polymer / silica microsphere composite membrane, the polymer / silica microsphere composite membrane is immersed in a hydrofluoric acid solution to remove the silica microspheres, and a separation membrane with a uniform pore size and a similar inverse opal structure is obtained.

[0016] Preferably, in step S2, the metal salt solution is a silver ion solution with a concentration of 0.1-10 g / L, the metal salt is one of silver chloride, silver nitrate, and silver acetate, and the reducing solution in the corresponding step S4 is one of sodium borohydride aqueous solution and aminoterephthalic acid / ethanol solution, and the reducing solution concentration is 0.1-10 g / L.

[0017] Preferably, in step S2, the metal salt solution is a sodium selenite solution with a concentration of 0.1-5 g / L, and the reducing solution in the corresponding step S4 is a sodium borohydride aqueous solution or a glutathione aqueous solution with a concentration of 0.1-10 g / L.

[0018] Preferably, in step S3, the immersion time is 10-60 min.

[0019] Preferably, in step S5, the immersion time is 10-60 min.

[0020] The invention discloses an antibacterial separation membrane uniformly loaded with metal nanoparticles. The metal nanoparticles are loaded in the pores of the separation membrane, and the size of the metal nanoparticles is 20-80nm.

[0021] The advantages and positive effects of the antibacterial separation membrane uniformly loaded with metal nanoparticles and the preparation method thereof described in the present invention are:

[0022] The invention has a simple preparation process, a short manufacturing cycle and low energy consumption. The inverse opal-like structured microfiltration membrane is prepared by sacrificing a silica microsphere template, and a metal nanoparticle antibacterial agent is further synthesized in situ inside the membrane pores to prepare an antibacterial membrane. The antibacterial membrane prepared in this way has an ordered structure with uniform pore size distribution and high retention, uniformly loads the antibacterial agent, avoids the escape of the antibacterial agent, increases the contact between bacteria and the antibacterial agent, and improves the antibacterial performance of the membrane. The invention has good application prospects in the field of antibacterial water treatment.

[0023] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a cross-sectional morphology of the silver nanoparticle-loaded antibacterial film obtained in Example 1 of the present invention;

[0025] Figure 2 The number of bacteria in the effluent after being treated with the silver nanoparticle-loaded antibacterial film obtained in Example 1 of the present invention;

[0026] Figure 3 This is a cross-sectional morphology of the antibacterial film loaded with selenium nanoparticles obtained in Example 2 of the present invention;

[0027] Figure 4 This is the number of bacteria in the effluent after being treated with the silver nanoparticle-loaded antibacterial film obtained in Example 2 of the present invention. DETAILED DESCRIPTION

[0028] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0029] Unless otherwise defined, technical or scientific terms used in the present invention shall have the common meanings understood by one having ordinary skills in the field to which the present invention belongs.

[0030] Example 1

[0031] A method for preparing an antibacterial separation membrane uniformly loaded with metal nanoparticles comprises the following steps:

[0032] (1) 20wt% of 500nm diameter silicon dioxide (SiO 2 ) Microspheres were dispersed with N,N-dimethylformamide to obtain SiO 2 Microsphere dispersion, SiO 2 10 wt% polyvinylidene fluoride was added to the microsphere dispersion to obtain a casting solution; the casting solution was poured on the surface of a glass plate and cured in a constant temperature oven at 80°C until the organic solvent evaporated to obtain a polymer / SiO 2 Microsphere composite membrane; polymer / SiO 2 The microsphere composite membrane was immersed in 4wt% hydrofluoric acid solution for 4h to remove SiO 2 Microspheres are used to prepare a separation membrane with a uniform pore size and a similar inverse opal structure.

[0033] (2) A silver nitrate solution with a concentration of 6 g / L was prepared, and the prepared separation membrane 1 was immersed in the silver nitrate solution for 30 min to obtain a separation membrane 2 that adsorbs silver ions.

[0034] (3) An 8 g / L sodium borohydride aqueous solution was prepared, and the prepared separation membrane 2 for adsorbing silver ions was immersed in the sodium borohydride aqueous solution for 30 min to obtain a separation membrane 3 loaded with silver nanoparticles.

[0035] Depend on Figure 1 It can be seen that the cross section of the antibacterial membrane presents a uniformly distributed pore structure, and obvious silver nanoparticles are observed inside the pores. The porosity of the antibacterial membrane tested by the weight method is 72%. The separation performance of the microfiltration membrane was tested by dead-end filtration. At a pressure of 0.1MPa, the pure water flux was 714L / m 2 h.

[0036] The raw material liquid adopts 10 4 CFU / mL Staphylococcus aureus suspension, the antibacterial performance of the membrane was tested by dead-end filtration, and the number of bacteria in the effluent was tested under a pressure of 0.1MPa. Test of the number of bacteria in the effluent: Take 0.1mL of bacterial solution and evenly apply it to LB medium for cultivation, count the number of bacterial colonies, and the antibacterial rate (BR) is calculated as follows:

[0037] ;

[0038] Among them, n 0 and n1 Represent the bacterial colony counts in the raw liquid and effluent, respectively.

[0039] After calculation, under the effect of antibacterial interception and sterilization performance, the number of bacteria in the effluent treated with the antibacterial membrane prepared in Example 1 is as follows: Figure 2 As shown, the antibacterial rate is about 99.93%.

[0040] Example 2

[0041] A method for preparing an antibacterial separation membrane uniformly loaded with metal nanoparticles comprises the following steps:

[0042] (1) 20wt% SiO with a diameter of 500nm 2 The microspheres were dispersed with N,N-dimethylformamide to obtain SiO 2 Microsphere dispersion, SiO 2 10 wt% polyvinylidene fluoride was added to the microsphere dispersion to obtain a casting solution; the casting solution was poured on the surface of a glass plate and cured in a constant temperature oven at 80°C until the organic solvent evaporated to obtain a polymer / SiO 2 Microsphere composite membrane; polymer / SiO 2 The microsphere composite membrane was immersed in 4wt% hydrofluoric acid solution for 4h to remove SiO 2 Microspheres are used to prepare a separation membrane with a uniform pore size and a similar inverse opal structure.

[0043] (2) A sodium selenite solution with a concentration of 0.2 g / L was prepared, and the prepared separation membrane 1 was immersed in the ammonium selenite solution for 30 min to obtain a separation membrane 2 that adsorbed selenium.

[0044] (3) An 8 g / L sodium borohydride aqueous solution was prepared, and the prepared separation membrane 2 for adsorbing selenium was immersed in the sodium borohydride aqueous solution for 30 min to obtain a separation membrane 3 loaded with selenium nanoparticles.

[0045] Depend on Figure 3 It can be seen that the cross section of the antibacterial membrane presents a uniformly distributed pore structure, and obvious selenium nanoparticles are observed inside the pores. The porosity of the antibacterial membrane tested by the weight method is 74%. The separation performance of the microfiltration membrane was tested by dead-end filtration. At a pressure of 0.1MPa, the pure water flux was 732L / m 2 h.

[0046] The antibacterial performance of the selenium nanoparticle-loaded membrane was tested by the same method as in Example 1. After calculation, under the effect of antibacterial interception and sterilization performance, the number of bacteria in the effluent treated with the antibacterial membrane prepared in Example 2 was as follows: Figure 4 As shown, the antibacterial rate is about 99.94%.

[0047] Example 3

[0048] A method for preparing an antibacterial separation membrane uniformly loaded with metal nanoparticles comprises the following steps:

[0049] (1) 20wt% of 500nm diameter silicon dioxide (SiO 2 ) Microspheres were dispersed with N,N-dimethylformamide to obtain SiO 2 Microsphere dispersion, SiO 2 10 wt% polyvinylidene fluoride was added to the microsphere dispersion to obtain a casting solution; the casting solution was poured on the surface of a glass plate and cured in a constant temperature oven at 80°C until the organic solvent evaporated to obtain a polymer / SiO 2 Microsphere composite membrane; polymer / SiO 2 The microsphere composite membrane was immersed in 4wt% hydrofluoric acid solution for 4h to remove SiO 2 Microspheres are used to prepare a separation membrane with a uniform pore size and a similar inverse opal structure.

[0050] (2) A silver nitrate solution with a concentration of 6 g / L was prepared, and the prepared separation membrane 1 was immersed in the silver nitrate solution for 30 min to obtain a separation membrane 2 that adsorbs silver ions.

[0051] (3) An 8 g / L aminoterephthalic acid / ethanol solution was prepared, and the prepared separation membrane 2 for adsorbing silver ions was immersed in the aminoterephthalic acid / ethanol solution for 40 min to obtain a separation membrane 3 loaded with silver nanoparticles.

[0052] Example 4

[0053] A method for preparing an antibacterial separation membrane uniformly loaded with metal nanoparticles comprises the following steps:

[0054] (1) 20wt% of 500nm diameter silicon dioxide (SiO 2 ) Microspheres were dispersed with N,N-dimethylformamide to obtain SiO 2 Microsphere dispersion, SiO 2 10 wt% polyvinylidene fluoride was added to the microsphere dispersion to obtain a casting solution; the casting solution was poured on the surface of a glass plate and cured in a constant temperature oven at 80°C until the organic solvent evaporated to obtain a polymer / SiO 2 Microsphere composite membrane; polymer / SiO 2 The microsphere composite membrane was immersed in 4wt% hydrofluoric acid solution for 4h to remove SiO 2 Microspheres are used to prepare a separation membrane with a uniform pore size and a similar inverse opal structure.

[0055] (2) A sodium selenite solution with a concentration of 0.2 g / L was prepared, and the prepared separation membrane 1 was immersed in the sodium selenite solution for 30 min to obtain a separation membrane 2 that adsorbed selenium.

[0056] (3) An 8 g / L glutathione aqueous solution was prepared, and the prepared separation membrane 2 for adsorbing selenium was immersed in the glutathione aqueous solution for 40 min to obtain a separation membrane 3 loaded with selenium nanoparticles.

[0057] The porosity, water flux and antibacterial performance of the separation membranes loaded with nano antibacterial agents prepared in Example 1 and Example 2 were tested. The test results are shown in Table 1.

[0058] Table 1

[0059] ;

[0060] According to the results in Table 1, Examples 1 and 2 of the present invention can retain good porosity and permeability by loading catalysts in the 10-like uniform porous membrane, while giving the separation membrane efficient antibacterial properties. Under the combined effects of interception and sterilization of the antibacterial membrane, the removal rate of Staphylococcus aureus is close to 100%, with good sterilization performance. The loaded metal nanoparticle antibacterial separation membrane synthesizes the catalyst in situ in the hole, controls the size of the catalyst, and the catalyst size is larger than the hole, so that the antibacterial agent can be prevented from overflowing. The antibacterial agent of the loaded metal nanoparticle antibacterial separation membrane is loaded inside each hole, and when bacteria pass through, it can increase contact and improve sterilization performance.

[0061] Therefore, the present invention adopts the above-mentioned antibacterial separation membrane with uniform load of metal nanoparticles and its preparation method to fix the metal nanoparticle antibacterial agent in the separation membrane with uniform pore distribution. The obtained antibacterial membrane can significantly improve the contact between the antibacterial agent and bacteria and improve the sterilization performance on the one hand, and can improve the uniformity and stability of the antibacterial agent loading on the other hand.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for preparing an antibacterial separation membrane uniformly loaded with metal nanoparticles, characterized in that: The following steps are involved: S1, preparing a separation membrane with uniform pore size; S2, preparing a metal salt solution; S3, immersing the separation membrane 1 prepared in step S1 in the metal salt solution prepared in step S2 for 10-60 min to obtain a separation membrane 2 that absorbs the metal salt solution; S4, preparing a reducing solution; S5, immersing the separation membrane 2 prepared in step S3 in the reducing solution prepared in step S4, the immersion time is 10-60 min, to obtain the separation membrane 3 loaded with metal nanoparticles, the size of the metal nanoparticles is 20-80 nm; In step S1, a sacrificial template method is used to prepare a separation membrane 1, wherein the pore structure of the separation membrane 1 is spherical holes, the pore structure is evenly distributed, and the pore structure size is 100-800 nm; In step S1, the specific steps of preparing the separation membrane 1 are as follows: 20 wt % of silica with a diameter of 500 nm is dispersed in an organic solvent to obtain a silica microsphere dispersion, 8-15 wt % of a polyvinylidene fluoride polymer is added to the silica microsphere dispersion, and the mixture is uniformly mixed to obtain a casting solution, the casting solution is cast on a glass plate, and the mixture is cured in a constant temperature oven at 80° C. until the organic solvent evaporates to obtain a polymer / silica microsphere composite membrane, and the polymer / silica microsphere composite membrane is immersed in a hydrofluoric acid solution to remove the silica microspheres, thereby obtaining a separation membrane with a uniform pore size and a similar inverse opal structure; In step S2, the metal salt solution is a silver ion solution with a concentration of 0.1-10 g / L, the metal salt is one of silver chloride, silver nitrate, and silver acetate, and the reducing solution in the corresponding step S4 is one of a sodium borohydride aqueous solution and an aminoterephthalic acid / ethanol solution, and the reducing solution concentration is 0.1-10 g / L; In step S2, the metal salt solution is a sodium selenite solution with a concentration of 0.1-5 g / L, and the reducing solution in the corresponding step S4 is a sodium borohydride aqueous solution or a glutathione aqueous solution with a concentration of 0.1-10 g / L.

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