CN113248778B - Preparation method and application of surface modified cellulose-based porous membrane - Google Patents

Abstract

The invention provides a preparation method and application of a surface modified cellulose-based porous membrane, belonging to the field of preparation of membrane materials; in the present invention, N-methylmorpholine-N-oxide/dimethyl sulfoxide/deionized water (NMMO/DMSO/H) is used ₂ O) is used as a solvent system of cellulose, after dissolution and organic solvent coagulation bath regeneration, a cellulose-based porous membrane with a uniform pore structure is obtained, and then surface modification is carried out to obtain the surface modified cellulose-based porous membrane, wherein the surface modified cellulose-based porous membrane has good application in biomacromolecule adsorption and fixation.

Description

Preparation method and application of a surface-modified cellulose-based porous membrane

technical field

The invention belongs to the field of preparation of membrane materials, and relates to a preparation method and application of a surface-modified cellulose-based porous membrane.

Background technique

At present, surface-modified porous membranes based on cellulose have been widely used in the fields of biomedicine, environment, chemical industry and food. Cellulose-based porous membranes are mostly prepared by the dissolving regeneration method. The cellulose is dissolved into a homogeneous solution and then regenerated. However, there are a large number of intramolecular and intermolecular hydrogen bonds in the molecular structure of cellulose, and the crystallinity is high. Insoluble in general organic solvent system.

In the traditional preparation method of surface-modified cellulose-based porous membrane, the cellulose solvent is mainly cuprammonium solution and CS ₂ /NaOH system, but the process route of using these two solvent systems to prepare cellulose membrane is complicated, and the raw materials and energy consumption are large. , and serious environmental pollution. In the current preparation method of the new cellulose-based porous membrane, the cellulose solvent system includes NaOH/urea, lithium chloride/dimethylacetamide (LiCl/DMAc), N-methylmorpholine-N-oxide (NMMO) ), ionic liquids, and zinc chloride, etc. These new solvent systems have the characteristics of green and pollution-free. However, the cellulose membranes obtained by using these solvent systems have a dense structure and less pore structure, resulting in a small specific surface area. Further application of cellulose membrane materials.

SUMMARY OF THE INVENTION

In view of the deficiencies in the prior art, the present invention provides a preparation method and application of a surface-modified cellulose-based porous membrane. In the present invention, using N-methylmorpholine-N-oxide/dimethyl sulfoxide/deionized water (NMMO/DMSO/H ₂ O) as the solvent system of cellulose, after dissolving and organic solvent coagulation bath After regeneration, a cellulose-based porous membrane with a uniform pore structure is obtained, and then chemical modification is performed to obtain the surface-modified cellulose-based porous membrane, and the surface-modified cellulose-based porous membrane is in the adsorption and immobilization of biological macromolecules. Has a good application.

The present invention first provides a surface-modified cellulose-based porous membrane, wherein the surface-modified cellulose-based porous membrane is modified based on the cellulose-based porous membrane; the cellulose-based porous membrane is made of N-methyl Morpholine-N-oxide/dimethyl sulfoxide/deionized water NMMO/DMSO/H ₂ O is a solvent system, which is obtained by regeneration and replacement of organic solvent coagulation bath, and has a uniform micron-scale macropore structure inside.

The present invention also provides a method for preparing the above-mentioned surface-modified cellulose-based porous membrane, which specifically includes the following steps:

(1) Preparation of cellulose-based porous membrane:

Add dimethyl sulfoxide DMSO to dry cellulose, then add a mixed solvent of N-methylmorpholine-N-oxide/deionized water NMMO/H ₂ O to get a mixed system, then add propyl gallate The stabilizer is mixed evenly, stirred, vacuum defoamed, scraped to form a film, immersed in an organic solvent coagulation bath for regeneration and replaced in a replacement bath, and dried to obtain a cellulose-based porous membrane;

(2) Preparation of surface-modified cellulose-based porous membrane:

Dissolving sodium periodate in acetate buffer, then immersing the cellulose-based porous membrane, shaking reaction under the condition of avoiding light, and washing, the surface-modified cellulose-based porous membrane is obtained.

Further, in step (1), the final concentration of the cellulose in the mixed system is 2-15 wt %; the NMMO in the mixed system is 40-50 wt %; the deionized water in the mixed system is 4-6 wt % %; DMSO in the mixed system is 35~48wt%.

Further, in step (1), the propyl gallate stabilizer is 0.2-1.0 wt % of the cellulose.

Further, in step (1), the stirring conditions are: stirring at 80-150° C. for 10 min-5 h.

Further, in step (1), the coagulation bath used after film formation includes one or more combinations of methanol, ethanol, acetone, etc., and the replacement time of immersion in the coagulation bath is 20min-1h.

Further, in step (1), the replacement bath includes one or more combinations including methanol, ethanol, acetone, isopropanol, n-butanol, etc., and the replacement time in the replacement bath is 12~36h.

Further, in step (2), the final concentration of sodium periodate is 1-10 mg/mL.

Further, in step (2), the concentration of the acetate buffer solution is 0.1 mol/L, and the pH is 4.

Further, in step (2), the condition of the shaking reaction is to stir the reaction at 4~40°C for 15min~10h.

The present invention also provides the application of the above-mentioned surface-modified cellulose-based porous membrane as a biomacromolecule immobilization carrier material.

Compared with the prior art, the beneficial effects of the present invention are:

In the present invention, cellulose is used as a raw material, which has abundant storage in nature, low price, high stability and good biocompatibility, and contains a large number of hydroxyl groups on the surface for later modification, which is an ideal raw material for preparing porous membranes.

In the present invention, the green solvent system N-methylmorpholine-N-oxide/dimethyl sulfoxide/deionized water (NMMO/DMSO/H ₂ O) is used to dissolve the cellulose, and then the organic solvent is used as a coagulation bath A cellulose-based porous membrane material is obtained, and chemical modification is performed based on the cellulose-based porous membrane material to obtain the surface-modified cellulose-based porous membrane.

The method used in the invention has the advantages of mild dissolution conditions, environmental friendliness and non-toxicity, simple operation process, suitable for large-scale production, etc. The prepared cellulose-based porous membrane material has a uniform porous internal structure, and then the obtained cellulose-based porous membrane material has the advantages of mild dissolution conditions, environmental friendliness and non-toxicity. The porous membrane is modified and modified on the surface, and the surface-modified cellulose-based porous membrane can be used as a solid carrier material for biological macromolecules such as enzymes and proteins.

Description of drawings

Figure 1 is a scanning electron microscope image of a cellulose-based porous membrane.

Figure 2 shows the reusability of lipase immobilized on a surface-modified cellulose-based porous membrane.

Detailed ways

The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited thereto.

Example 1:

Add dimethyl sulfoxide DMSO to dry cellulose, then add a mixed solvent of N-methylmorpholine-N-oxide/deionized water NMMO/H ₂ O, and add propyl gallate stabilizer and mix well , obtain a mixed system, in the system, the concentration of cellulose is 5wt%, the proportion of DMSO is 45wt%, the proportion of NMMO is 45wt%, the proportion of deionized water is 5wt%, and propyl gallate is 0.5wt% of cellulose ; Stir at 100°C for 2h, then vacuum defoaming, scrape the obtained cellulose solution on a glass plate to make a film and immerse it in an acetone coagulation bath for 40min, then fully replace it in an isopropanol solution for 15h, and finally The cellulose-based porous membrane is obtained after drying under vacuum heating.

To modify the surface of the cellulose-based porous membrane, the specific steps are as follows: Weigh 40 mg of sodium periodate and completely dissolve it in 40 mL of 0.1 M acetate buffer (pH 4.0), and then take the cellulose-based porous membrane and immerse it in the In the above solution of sodium periodate, the reaction system was stirred and reacted at room temperature for 10 hours under the condition of avoiding light, and after the reaction was completed, it was fully washed with ice water for at least three times, and the surface-modified cellulose base with aldehyde groups was obtained. Porous membrane.

Figure 1 is a scanning electron microscope image of a cellulose-based porous membrane. It can be seen that the material has a uniform micron-scale macropore internal pore structure.

Example 2:

Add dimethyl sulfoxide DMSO to dry cellulose, then add a mixed solvent of N-methylmorpholine-N-oxide/deionized water NMMO/H ₂ O, and add propyl gallate stabilizer and mix well , a mixed system is obtained, in which the concentration of cellulose is 6wt%, the proportion of DMSO is 44wt%, the proportion of NMMO is 46wt%, the proportion of deionized water is 4wt%, and propyl gallate is 0.6wt% of cellulose ; Stir at 120 °C for 1 h, then vacuum defoaming, scrape the obtained cellulose solution on a glass plate to form a film and immerse it in an acetone coagulation bath for 50 min, then fully replace it in an isopropanol solution for 20 h, and finally The cellulose-based porous membrane is obtained after drying under vacuum heating.

To modify the surface of the cellulose-based porous membrane, the specific steps are as follows: Weigh 200 mg of sodium periodate and completely dissolve it in 40 mL of 0.1 M acetate buffer (pH 4.0), and then take the cellulose-based porous membrane and immerse it in In the above solution of sodium periodate, the reaction system was stirred and reacted at room temperature for 5 hours under the condition of avoiding light, and after the reaction was completed, the surface-modified cellulose-based aldehyde group was obtained by fully washing with ice water for at least three times. Porous membrane.

Example 3:

Add dimethyl sulfoxide DMSO to dry cellulose, then add a mixed solvent of N-methylmorpholine-N-oxide/deionized water NMMO/H ₂ O, and add propyl gallate stabilizer and mix well , a mixed system is obtained, in which the concentration of cellulose is 4wt%, the proportion of DMSO is 50wt%, the proportion of NMMO is 40wt%, the proportion of deionized water is 6wt%, and propyl gallate is 0.6wt% of cellulose ; Stir at 80°C for 5h, then vacuum defoaming, scrape the obtained cellulose solution on a glass plate to form a film and immerse it in an acetone coagulation bath for 40 minutes, and then fully replace it in an isopropanol solution for 12h, Finally, the cellulose-based porous membrane is obtained after vacuum heating and drying.

To modify the surface of the cellulose-based porous membrane, the specific steps are as follows: Weigh 200 mg of sodium periodate and completely dissolve it in 40 mL of 0.1 M acetate buffer (pH 4.0), and then take the cellulose-based porous membrane and immerse it in In the above solution of sodium periodate, the reaction system was stirred and reacted at 30 °C for 2 h under the condition of avoiding light. After the reaction was completed, it was fully washed with ice water for at least three times, and the surface-modified fibers with aldehyde groups were obtained. base porous membrane.

Example 4:

Using the surface-modified cellulose-based porous membrane with aldehyde groups prepared in Example 1 to carry out adsorption and immobilization treatment on lipase, the specific steps are:

The lipase was fully dissolved in phosphate buffer (pH 7.0, 10 mM) to prepare a solution with a concentration of 1.0 mg/mL, and then the surface-modified cellulose-based porous membrane with aldehyde groups was immersed in the above solution. , the reaction was shaken at room temperature for the adsorption and immobilization of lipase. After 10 hours of reaction, the content of lipase in the solution before and after adsorption was measured by Coomassie brilliant blue method, and the enzyme adsorption and immobilization capacity of the surface-modified cellulose-based porous membrane with aldehyde groups was 5.5 mg/g. The lipase adsorbed and immobilized on the surface-modified cellulose-based porous membrane with aldehyde groups was tested for reuse. The results are shown in Figure 2. After repeated use for 5 times, the activity of the enzyme did not decrease significantly, indicating that the adsorption immobilization The lipase on the surface-modified cellulose-based porous membrane with aldehyde groups has excellent reusability.

The embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above-mentioned embodiments, and any obvious improvement, replacement or Modifications all belong to the protection scope of the present invention.

Claims (10)

1. A method of preparing a surface-modified cellulose-based porous membrane, comprising:

(1) preparation of cellulose-based porous membrane:

to the dried cellulose was added dimethyl sulfoxide DMSO followed by N-methylmorpholine-N-oxide/deionized water NMMO/H ₂ O to obtain a mixed system, then adding a propyl gallate stabilizer, uniformly mixing, stirring, defoaming in vacuum, scraping to form a film, immersing in an organic solvent coagulation bath for regeneration, replacing in a replacement bath, and drying to obtain a cellulose-based porous membrane;

(2) preparing a surface modified cellulose base porous membrane:

and dissolving sodium periodate in an acetic acid buffer solution, then immersing the cellulose-based porous membrane, carrying out oscillation reaction under the condition of keeping out of the sun, and washing to obtain the surface modified cellulose-based porous membrane.

2. The method of preparing a surface-modified cellulose-based porous membrane according to claim 1, wherein in the step (1), the final concentration of the cellulose in the mixed system is 2 to 15wt%, the final concentration of NMMO in the mixed system is 40 to 50wt%, the final concentration of deionized water in the mixed system is 4 to 6wt%, the final concentration of DMSO in the mixed system is 35 to 48wt%, and the final concentration of the propyl gallate stabilizer is 0.2 to 1.0wt% of the cellulose.

3. The method for preparing the surface-modified cellulose-based porous membrane according to claim 1, wherein the stirring conditions in step (1) are: stirring for 10 min-5 h at 80-150 ℃.

4. The method for preparing the surface-modified cellulose-based porous membrane according to claim 1, wherein in the step (1), the coagulation bath used after the membrane formation comprises one or more of methanol, ethanol and acetone, and the membrane is immersed in the coagulation bath for 20min to 1 h.

5. The method for preparing the surface-modified cellulose-based porous membrane according to claim 1, wherein in the step (1), the displacement bath comprises one or more of methanol, ethanol, acetone, isopropanol and n-butanol, and the displacement time in the displacement bath is 12-36 h.

6. The method for preparing a surface-modified cellulose-based porous membrane according to claim 1, wherein the final concentration of sodium periodate in the step (2) is 1 to 10 mg/mL.

7. The method for preparing a surface-modified cellulose-based porous membrane according to claim 1, wherein the acetic acid buffer solution has a concentration of 0.1mol/L and a pH of 4 in the step (2).

8. The method for preparing the surface-modified cellulose-based porous membrane according to claim 1, wherein the shaking reaction is performed at 4 to 40 ℃ for 15min to 10h under stirring conditions in the step (2).

9. The surface-modified cellulose-based porous membrane prepared by the method according to any one of claims 1 to 8, wherein the surface-modified cellulose-based porous membrane is modified based on a cellulose-based porous membrane; the cellulose-based porous membrane is prepared from N-methylmorpholine-N-oxide/dimethyl sulfoxide/deionized water NMMO/DMSO/H ₂ O is a solvent system, is obtained by regeneration of an organic solvent coagulation bath and replacement in a replacement bath, and has a uniform micron-sized macroporous structure inside.

10. Use of the surface modified cellulose-based porous membrane according to claim 9 as a biomacromolecule immobilization support material.

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