Method for preparing antibacterial ultrafiltration membrane based on modified bacterial cellulose, ultrafiltration membrane and application

Abstract

The invention belongs to the field of separation, and particularly relates to a method for preparing a bacteriostatic ultrafiltration membrane based on modified bacterial cellulose, the ultrafiltration membrane and application. The antibacterial ultrafiltration membrane prepared based on the modified bacterial cellulose comprises a base membrane and the modified bacterial cellulose arranged on the surface of the base membrane. The used modified bacterial cellulose has a long-acting antibacterial effect, is used for preparing the ultrafiltration membrane, effectively prevents attachment of microorganisms, and enhances the anti-pollution effect of the membrane. The preparation method is simple to operate. The bacterial cellulose used in the invention is a natural biological substance, and is green, healthy and pollution-free.

Description

Technical Field

[0001] The invention belongs to the field of separation, and specifically relates to a method for preparing an antibacterial ultrafiltration membrane based on modified bacterial cellulose, an ultrafiltration membrane and an application thereof. Background Art

[0002] As a pressure-driven membrane, ultrafiltration membrane has lower energy consumption, smaller footprint, and milder conditions than traditional processes, and has been widely used in water treatment and various industrial applications. However, the material composition of the water treatment process is complex, and some components are very likely to cause membrane fouling, affecting the flux, service life and efficiency of the membrane. Among them, microbial contamination in drinking water, in particular, will not only cause membrane damage, but also affect human health. Therefore, solving biological contamination has become a key direction for the development of membrane technology.

[0003] In the existing antibacterial membrane technology, metal particles such as Ag and Cu are usually introduced to achieve antibacterial effects. However, as heavy metals, Ag and Cu themselves and their ions will be released into the environment, which cannot guarantee long-term antibacterial effects and may threaten human health. Therefore, it is urgent to develop a green antibacterial material modified ultrafiltration membrane to achieve long-term antibacterial use of ultrafiltration membrane. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for preparing an antibacterial ultrafiltration membrane based on modified bacterial cellulose, an ultrafiltration membrane and an application thereof.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] An antibacterial ultrafiltration membrane prepared based on modified bacterial cellulose comprises a basement membrane and modified bacterial cellulose arranged on the surface of the basement membrane.

[0007] The base film and the modified bacterial cellulose are bonded by using polydopamine.

[0008] The modified bacterial cellulose is prepared by the following method: dissolving bacterial cellulose suspension in alkaline solution, stirring evenly, and then adding ammonium salt containing halogen; after the reaction is completed, adjusting the pH to neutral to obtain the modified bacterial cellulose.

[0009] The halogen-containing ammonium salt is dodecyldimethylbenzylammonium chloride or 2-bromoethylamine hydrobromide.

[0010] The mass ratio of dodecyl dimethyl benzyl ammonium chloride to bacterial cellulose is 1:(0.2-0.6); preferably 1:0.4;

[0011] The mass ratio of 2-bromoethylamine hydrobromide to bacterial cellulose is 1:(0.5-1); preferably 1:0.7;

[0012] Preferably, the diameter of the bacterial cellulose in the bacterial cellulose suspension is 50-100 nm.

[0013] The present invention also includes a method for preparing an antibacterial ultrafiltration membrane based on modified bacterial cellulose, which adopts the following steps: adding tris-HCl buffer solution to the modified bacterial cellulose to adjust the pH value to alkaline, and adding dopamine and stirring evenly to obtain a mixed solution; depositing the mixed solution on a base membrane to obtain an antibacterial ultrafiltration membrane.

[0014] The mass ratio of bacterial cellulose to dopamine is 1:(3-5); preferably 1:4.

[0015] The ratio of modified bacterial cellulose to base film is 0.4-2.8g / m 2 .

[0016] The base membrane is a PES, PAN or PSU base membrane; preferably, the base membrane is immersed in ultrapure water for at least 72 hours.

[0017] The present invention also includes an application of the ultrafiltration membrane.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] (1) The modified bacterial cellulose used in the present invention has a long-lasting antibacterial effect and is used in the preparation of ultrafiltration membranes to effectively prevent microbial attachment and enhance the anti-fouling effect of the membranes.

[0020] (2) The preparation method used in the present invention is simple to operate.

[0021] (3) The bacterial cellulose used in the present invention is a natural biological material, which is green, healthy and pollution-free. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The flowchart of the preparation process of antibacterial ultrafiltration membrane based on modified bacterial cellulose;

[0023] Figure 2 The antibacterial effect diagram of ultrafiltration membranes (1, 2, 3) prepared using modified bacterial cellulose and an ultrafiltration membrane (0) prepared without modification;

[0024] Figure 3 The infrared comparison pictures of ultrafiltration membrane and base membrane prepared by using modified bacterial cellulose;

[0025] Figure 4 The flux turbidity graphs are for ultrafiltration membranes (1, 2, 3, 4) prepared using modified bacterial cellulose and a base membrane (0) prepared without modification. DETAILED DESCRIPTION

[0026] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and the best embodiments.

[0027] Example 1

[0028] The method for preparing an antibacterial ultrafiltration membrane based on modified bacterial cellulose comprises the following steps:

[0029] 1) Preparation of modified bacterial cellulose. In this example, dodecyl dimethyl benzyl ammonium chloride is used as an example for illustration.

[0030] Specifically, the following steps are adopted: 4 g of bacterial cellulose suspension (volume concentration 0.8%) is weighed, dissolved in 1 mol / L NaOH solution, placed on a magnetic stirrer and stirred evenly for use; 0.08 g of dodecyl dimethyl benzyl ammonium chloride (the ratio of dodecyl dimethyl benzyl ammonium chloride to bacterial cellulose can be 1:0.2, 1:0.4, 1:0.6; preferably 1:0.6 is described as a preferred example) is dissolved in the bacterial cellulose solution, stirred for reaction at room temperature for 4 hours, and after the reaction is completed, the pH is adjusted to 7 to remove excess substances.

[0031] 2) Adding tris-HCl buffer solution to the modified bacterial cellulose to adjust the pH value to alkaline, and adding dopamine and stirring to obtain a mixed solution; depositing the mixed solution on the basement membrane to obtain an antibacterial ultrafiltration membrane (flow chart as shown in FIG. Figure 1 ), specifically comprising the following steps:

[0032] Tris-HCl buffer solution was added to the solution obtained in step 1) to adjust the pH to 8.5, and 0.12 g of dopamine (mass ratio of bacterial cellulose to dopamine was 1:4) was added to the solution in step 1) and stirred evenly.

[0033] 3) Take the mixed solution obtained in step 2) at 0.7 g / m 2 The modified bacterial cellulose (in terms of mass of modified bacterial cellulose / membrane area) was deposited on a base membrane (the PVDF base membrane was soaked in ultrapure water for at least 72 hours) by vacuum filtration to obtain an antibacterial ultrafiltration membrane based on modified bacterial cellulose. The infrared spectrum of the antibacterial ultrafiltration membrane of the obtained modified bacterial cellulose was similar to that of the ordinary base membrane PVDF as shown in Figure 3 Shown, from Figure 3 It can be seen that the ammonium salt is grafted onto the surface of bacterial cellulose, and the modified bacterial cellulose is attached to the PVDF membrane.

[0034] Example 2

[0035] The difference between Example 2 and Example 1 is that in step 3), the 2 The film is deposited onto the base film by vacuum filtration.

[0036] Example 3

[0037] The difference between Example 3 and Example 1 is that in step 3), the 2 The film is deposited onto the base film by vacuum filtration.

[0038] Example 4

[0039] The method for preparing an antibacterial ultrafiltration membrane based on modified bacterial cellulose comprises the following steps:

[0040] 1) Preparation of modified bacterial cellulose. In this embodiment, 2-bromoethylamine hydrobromide is used as an example for illustration. Specifically, the following steps are adopted: 2 g bacterial cellulose suspension (volume concentration 0.8%) is weighed, dissolved in 4 mol / L NaOH solution, placed on a magnetic stirrer and stirred evenly for use; 4 mol / L 2-bromoethylamine hydrobromide aqueous solution (the final concentration of 2-bromoethylamine hydrobromide in the mixed solution is 0.09 g / mL, and the final concentration of bacterial cellulose is 0.066 g / ml) is dissolved in the bacterial cellulose solution, stirred at room temperature for 4 hours, and the pH is adjusted to 7 after the reaction is completed, and the excess substances are removed. Steps 2) and 3) are the same as those in Example 1.

[0041] Comparative Example 1

[0042] Comparative Example 1 is a base membrane containing only dopamine, which is prepared in the following manner: 0.12 g of dopamine is added to a tris-HCl buffer solution to adjust the pH to 8.5 to obtain a mixed solution, and the mixed solution is deposited on a base membrane by vacuum filtration (the PVDF base membrane is soaked in ultrapure water for at least 72 hours) to obtain a dopamine ultrafiltration membrane.

[0043] Comparative Example 2

[0044] Comparative Example 2 is a base film containing only modified bacterial cellulose, which is prepared in the following manner: bacterial cellulose is modified in the same manner as in Example 1, and the modified bacterial cellulose mixed solution is heated at 0.7 g / m 2 The modified bacterial cellulose (in terms of mass / membrane area) is deposited onto a base membrane (the PVDF base membrane is soaked in ultrapure water for at least 72 hours) by vacuum filtration to obtain an antibacterial ultrafiltration membrane based on modified bacterial cellulose.

[0045] The antibacterial properties of the embodiments and comparative examples were tested using the inhibition zone method. Figure 2 It is shown that, among them, No. 0 is the result of the comparative example, and No. 1, 2, and 3 correspond to the results of Examples 1, 2, and 3 respectively. It can be seen from the results that after adding modified bacterial cellulose, the PVDF ultrafiltration membrane has an antibacterial effect.

[0046] At the same time, the flux of Examples 1-4 and Comparative Example 1 was measured, and the results are as follows: Figure 4 It can be seen that the turbidity of water after filtration with the ultrafiltration membrane containing modified bacterial cellulose is lower and the filtration effect is better; the flux increases first and then decreases with the increase of the amount of modified bacterial cellulose, so the amount of modified bacterial cellulose needs to be limited to 0.4-2.8g / m 2 .

[0047] Comparative Example 2 was compared with Example 1, and the adhesion of modified bacterial cellulose on the membrane surface was tested after one week of use. It was found that the antibacterial effect, flux and turbidity of Comparative Example 2 were reduced to a certain extent compared with Example 1. The results showed that the modified bacterial cellulose could be well attached to the PVDF membrane surface after adding dopamine.

[0048] In summary, (1) the modified bacterial cellulose used in the present invention has a long-lasting antibacterial effect, and is used in the preparation of ultrafiltration membranes, effectively preventing microbial attachment and enhancing the anti-fouling effect of the membranes. (2) The preparation method used in the present invention is simple to operate. (3) The bacterial cellulose used in the present invention is a natural biological material, which is green, healthy and pollution-free.

[0049] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing an antibacterial ultrafiltration membrane based on modified bacterial cellulose, characterized in that: The invention comprises a base film and modified bacterial cellulose arranged on the surface of the base film.

2. The method for preparing an antibacterial ultrafiltration membrane based on modified bacterial cellulose according to claim 1, characterized in that: The base film and the modified bacterial cellulose are bonded by using polydopamine.

3. The method for preparing an antibacterial ultrafiltration membrane based on modified bacterial cellulose according to claim 1, characterized in that: The modified bacterial cellulose is prepared by the following method: dissolving bacterial cellulose suspension in alkaline solution, stirring evenly, and then adding ammonium salt containing halogen; after the reaction is completed, adjusting the pH to neutral to obtain the modified bacterial cellulose.

4. The method for preparing an antibacterial ultrafiltration membrane based on modified bacterial cellulose according to claim 3, characterized in that: The halogen-containing ammonium salt is dodecyldimethylbenzylammonium chloride or 2-bromoethylamine hydrobromide.

5. The method for preparing an antibacterial ultrafiltration membrane based on modified bacterial cellulose according to claim 4, characterized in that: The mass ratio of dodecyl dimethyl benzyl ammonium chloride to bacterial cellulose is 1:(0.2-0.6); preferably 1:0.4; The mass ratio of 2-bromoethylamine hydrobromide to bacterial cellulose is 1:(0.5-1); preferably 1:0.7; Preferably, the diameter of the bacterial cellulose in the bacterial cellulose suspension is 50-100 nm.

6. A method for preparing an antibacterial ultrafiltration membrane based on modified bacterial cellulose according to any one of claims 1 to 5, characterized in that: The following steps are adopted: adding tris-HCl buffer solution to the modified bacterial cellulose to adjust the pH value to alkaline, adding dopamine and stirring evenly to obtain a mixed solution; and depositing the mixed solution on a base membrane to obtain an antibacterial ultrafiltration membrane.

7. The method for preparing an antibacterial ultrafiltration membrane based on modified bacterial cellulose according to claim 1, characterized in that: The mass ratio of bacterial cellulose to dopamine is 1:(3-5); preferably 1:

4.

8. The method for preparing an antibacterial ultrafiltration membrane based on modified bacterial cellulose according to claim 1, characterized in that: The ratio of modified bacterial cellulose to base film is 0.4-2.8g / m 2 .

9. The method for preparing an antibacterial ultrafiltration membrane based on modified bacterial cellulose according to claim 1, characterized in that: The base membrane is a PES, PAN or PSU base membrane; preferably, the base membrane is immersed in ultrapure water for at least 72 hours.

10. Use of the ultrafiltration membrane according to any one of claims 1 to 5.

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