Preparation method of cerium oxide nanoparticle modified bacterial cellulose aerogel and application of cerium oxide nanoparticle modified bacterial cellulose aerogel in field of gas filtration

Abstract

The invention discloses cerium oxide nano-particle modified bacterial cellulose aerogel, a preparation method thereof and application of the cerium oxide nano-particle modified bacterial cellulose aerogel in the field of gas filtration. According to the method, a low-temperature in-situ synthesis technology is adopted, CeO2 nanoparticles with good dispersity are uniformly loaded in a bacterial cellulose three-dimensional porous network, and the antibacterial efficiency of the material is remarkably improved. On the basis of keeping excellent adsorption performance and gas permeability, the obtained composite aerogel material can also avoid the problems of bacterium breeding and secondary pollution in a filtering system, the service life of the material is prolonged, and the air purification efficiency is improved. The material is simple and convenient in preparation process and low in energy consumption, has a good application prospect, and can be widely applied to the fields of medical protection, air filtration, antibacterial functional materials and the like.

Description

Technical Field

[0001] The present invention belongs to the field of composite materials, and in particular relates to a bacterial cellulose aerogel modified with cerium oxide nanoparticles, a preparation method thereof, and applications thereof in the field of gas filtration. Background Art

[0002] In recent years, with the continuous deepening of research on nanomaterials and sustainable bio-based materials, functionalized aerogels have shown broad application prospects in environmental remediation, biomedicine, catalysis, and energy storage due to their excellent specific surface area, controllable pore structure, and excellent physical and chemical properties. As a green and sustainable natural polymer material, bacterial cellulose aerogel (BCA), a natural polymer material derived from biosynthesis, has a good three-dimensional network structure, high porosity, low density, and excellent mechanical properties. It can effectively intercept and adsorb harmful gas molecules and particulate matter in the air, and has great application prospects in gas filtration and particulate matter capture. Studies have shown that by modifying its surface or compounding it with functional materials, the aerogel's adsorption and filtration capabilities for specific pollutants can be further optimized, providing new ideas and methods for solving air pollution problems.

[0003] Cerium oxide nanoparticles (Cerium Oxide Nanoparticles, CeO2 NPs) is an important functional rare earth oxide with reversible Ce 3+ / Ce 4+ Redox properties and excellent surface activity. In recent years, the application of CeO2 in the field of antibacterial has gradually attracted attention. Studies have shown that CeO2 nanoparticles can catalyze the production of reactive oxygen species (ROS) such as OH and O2 - , destroying bacterial cell wall structures and inhibiting the normal function of proteins and DNA, effectively killing a variety of Gram-positive and Gram-negative bacteria, demonstrating significant antibacterial properties. Compared to traditional antimicrobial agents, CeO2 is less likely to develop drug resistance and possesses excellent stability and biosafety, thus showing great potential for application in antimicrobial dressings, filtration membranes, and wound treatment.

[0004] Loading CeO2 nanoparticles into bacterial cellulose aerogels not only effectively limits CeO2 aggregation through the porous structure of BCA, improving its dispersibility and stability, but also imparts new functional properties to the aerogels, such as antibacterial and antioxidant properties, and catalytic activity. Therefore, constructing a bacterial cellulose aerogel composite modified with cerium oxide nanoparticles is expected to open up new application paths in medical treatment, environmental management, and functional materials, and has important research significance and broad application potential. Summary of the Invention

[0005] The present invention relates to a bacterial cellulose aerogel modified with cerium oxide nanoparticles and a preparation method thereof, which is specifically applied to the field of functional materials such as air purification and gas filtration, and belongs to the cross-technical category of functional nanocomposites and porous structure materials.

[0006] The present invention aims to uniformly load cerium dioxide nanoparticles into the three-dimensional network structure of bacterial cellulose aerogel through a low-temperature in-situ synthesis method, giving the aerogel efficient gas purification and antibacterial functions. The bacterial cellulose aerogel modified with CeO2 has a well-developed pore structure and an ultra-large specific surface area, which can efficiently capture particulate matter (PM) in the air and achieve deep physical adsorption purification of the gas. Because the bacterial cellulose aerogel itself cannot effectively kill captured bacteria, the antibacterial activity of CeO2 nanoparticles is used to kill bacteria and other microorganisms trapped in the aerogel, avoiding secondary contamination caused by microbial growth and ensuring the long-term cleanliness and safety of the filtered gas.

[0007] The specific steps include:

[0008] Step 1: At room temperature, cut the bacterial cellulose gel film into 8*8*1cm 3 , washed several times in deionized water to remove other components;

[0009] Step 2, immersing the washed bacterial cellulose in a Ce(NO3)2·6H2O solution;

[0010] Step 3, stirring continuously at room temperature for 1 hour, adding hexamethylenetetramine solution dropwise during stirring, and continuing the reaction time;

[0011] Step 4: After the reaction is completed, the mixture is washed with ultrapure water, frozen with liquid nitrogen, freeze-dried for 12 hours, and dried in a vacuum drying oven for 12 hours to obtain a bacterial cellulose aerogel composite material modified with cerium oxide nanoparticles.

[0012] Step 5: Conduct antibacterial and filtration tests on the bacterial cellulose aerogel composite material modified with cerium oxide nanoparticles.

[0013] Preferably, in step 2, the Ce(NO3)2·6H2O solution is added to prepare a volume concentration of 0.1M.

[0014] Preferably, in step 3, C6H 12 The volume concentration of N4 solution is 0.5~1M.

[0015] Preferably, the reaction time in step 3 is set to 6 to 24 hours.

[0016] Preferably, in step 4, the freeze-drying temperature is -70°C, the drying time is 12 hours, and the atmospheric pressure is 0.05 Pa.

[0017] Preferably, the vacuum drying temperature in step 4 and step 5 is 80° C. and the drying time is 12 h.

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

[0019] (1) Avoid the high-temperature calcination process in traditional CeO2 preparation, reduce energy consumption, simplify the operation process, and have good industrial feasibility;

[0020] (2) The abundant hydroxyl sites and three-dimensional network structure on the surface of bacterial cellulose effectively limit the aggregation of CeO2 and improve the uniformity of nanoparticle distribution;

[0021] (3) The prepared composite material has high porosity, light weight and good gas permeability, giving it excellent air filtration performance;

[0022] (4) This material has antibacterial properties and is expected to be used in antioxidant coatings, medical dressings, catalytic purification, and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is the XPS spectrum of the bacterial cellulose aerogel modified with cerium oxide nanoparticles synthesized in Example 1. DETAILED DESCRIPTION

[0024] The present invention is further described in detail below with reference to the embodiments and accompanying drawings.

[0025] A bacterial cellulose aerogel modified with cerium oxide nanoparticles and its preparation method

[0026] Step 1: At room temperature, cut the bacterial cellulose gel film into 8*8*1cm 3 , added to 80g deionized water and washed three times in sequence;

[0027] Step 2: Immerse the washed bacterial cellulose in 100 mL of 0.1 M Ce(NO3)2·6H2O solution;

[0028] Step 3: Stirring was continued at room temperature for 1 h. During the stirring process, 100 mL of 0.5 M hexamethylenetetramine solution was added dropwise and the reaction was continued for 6 h.

[0029] Step 4: After the reaction is completed, the mixture is washed thoroughly with ultrapure water, then frozen in liquid nitrogen at 0.05 Pa and -70°C, freeze-dried for 12 hours, and then dried in a vacuum drying oven for 12 hours to obtain a bacterial cellulose aerogel composite material modified with cerium oxide nanoparticles;

[0030] Step 5: Antibacterial and filtration tests were performed on the bacterial cellulose aerogel composite modified with cerium oxide nanoparticles.

[0031] Example 1:

[0032] Step 1: At room temperature, cut the bacterial cellulose gel film into 8*8*1cm 3 , added to 80g deionized water and washed three times in sequence;

[0033] Step 2: Immerse the washed bacterial cellulose in 100 mL of 0.1 M Ce(NO3)2·6H2O solution;

[0034] Step 3: Stir continuously at room temperature for 1 h. Add 100 mL of 0.5 M hexamethylenetetramine solution dropwise during stirring and continue the reaction for 12 h.

[0035] Step 4: After the reaction is completed, the mixture is washed thoroughly with ultrapure water, then frozen in liquid nitrogen at 0.05 Pa and -70°C, freeze-dried for 12 hours, and then dried in a vacuum drying oven for 12 hours to obtain a bacterial cellulose aerogel composite material modified with cerium oxide nanoparticles;

[0036] Step 5: Antibacterial and filtration tests were performed on the bacterial cellulose aerogel composite modified with cerium oxide nanoparticles.

[0037] Example 2

[0038] Step 1: At room temperature, cut the bacterial cellulose gel film into 8*8*1cm 3 , added to 80g deionized water and washed three times in sequence;

[0039] Step 2: Immerse the washed bacterial cellulose in 100 mL of 0.1 M Ce(NO3)2·6H2O solution;

[0040] Step 3: Stirring was continued at room temperature for 1 h. During the stirring process, 100 mL of 0.5 M hexamethylenetetramine solution was added dropwise and the reaction was continued for 24 h.

[0041] Step 4: After the reaction is completed, the mixture is washed thoroughly with ultrapure water, then frozen in liquid nitrogen at 0.05 Pa and -70°C, freeze-dried for 12 hours, and then dried in a vacuum drying oven for 12 hours to obtain a bacterial cellulose aerogel composite material modified with cerium oxide nanoparticles;

[0042] Step 5: Antibacterial and filtration tests were performed on the bacterial cellulose aerogel composite modified with cerium oxide nanoparticles.

[0043] Example 3

[0044] Step 1: At room temperature, cut the bacterial cellulose gel film into 8*8*1cm 3 , added to 80g deionized water and washed three times in sequence;

[0045] Step 2: Immerse the washed bacterial cellulose in 100 mL of 0.1 M Ce(NO3)2·6H2O solution;

[0046] Step 3: Stirring was continued at room temperature for 1 h. During the stirring process, 100 mL of 1 M hexamethylenetetramine solution was added dropwise and the reaction was continued for 12 h.

[0047] Step 4: After the reaction is completed, the mixture is washed thoroughly with ultrapure water, then frozen in liquid nitrogen at 0.05 Pa and -70°C, freeze-dried for 12 hours, and then dried in a vacuum drying oven for 12 hours to obtain a bacterial cellulose aerogel composite material modified with cerium oxide nanoparticles;

[0048] Step 5: Antibacterial and filtration testing of cerium oxide nanoparticle-modified bacterial cellulose aerogel composites

[0049] Example 4

[0050] Step 1: At room temperature, cut the bacterial cellulose gel film into 8*8*1cm 3 , added to 80g deionized water and washed three times in sequence;

[0051] Step 2: Immerse the washed bacterial cellulose in 100 mL of 0.1 M Ce(NO3)2·6H2O solution;

[0052] Step 3: Stirring was continued at room temperature for 1 h. During the stirring process, 90 mL of 2 M sodium hydroxide solution was added dropwise and the reaction was continued for 24 h.

[0053] Step 4: After the reaction is completed, the mixture is washed thoroughly with ultrapure water, then frozen in liquid nitrogen at 0.05 Pa and -70°C, freeze-dried for 12 hours, and then dried in a vacuum drying oven for 12 hours to obtain a bacterial cellulose aerogel composite material modified with cerium oxide nanoparticles;

[0054] Step 5: Antibacterial and filtration tests were performed on the bacterial cellulose aerogel composite modified with cerium oxide nanoparticles.

[0055] Comparative Example 1:

[0056] This comparative example is basically the same as Example 1, except that the reaction time is extended from 6 h to 12 h after the hexamethylenetetramine solution is added.

[0057] The results showed that when the reaction time was extended from 6 h to 12 h, the precursor Ce(NO3)2 had more sufficient reaction time and was more completely converted into CeO2. The nanoparticle loading increased and the particle size increased to 15 nm. However, due to the sustained release effect of hexamethylenetetramine controlling the growth rate, it was still able to maintain good dispersion.

[0058] Comparative Example 2:

[0059] This comparative example is basically the same as Example 1, except that the reaction time is extended from 6 h to 24 h after the hexamethylenetetramine solution is added.

[0060] The results show that extending the reaction time from 6h to 24h almost completely consumes the precursor Ce(NO3)2, and the loading capacity further increases. However, the excessively long reaction time causes particle agglomeration, forming larger particles, which reduces the specific surface area. In addition, small particles dissolve and large particles grow, leading to local agglomeration and reduced active site exposure. Excessive loading causes corrosion of the fiber surface and collapse of the aerogel pores. Despite the highest loading capacity, particle agglomeration and increased size reduce the effective active surface area, resulting in a decrease in activity per unit mass, and the overall performance is inferior to the sample with a continuous reaction time of 12h.

[0061] Comparative Example 3: This comparative example is basically the same as Example 1, except that 100 mL of 0.5 M hexamethylenetetramine solution is added instead of 100 mL of 1 M hexamethylenetetramine solution.

[0062] The results showed that the resulting composite material had a relatively uniform distribution of cerium oxide particles, large particle size, and good structural integrity. Increasing the concentration of the hexamethylenetetramine solution promoted the rapid nucleation of cerium oxide particles, leading to more uniform deposition on the bacterial cellulose surface and significantly improving the antibacterial and filtration capabilities of the material. However, the hexamethylenetetramine concentration should be carefully controlled to avoid particle agglomeration or structural damage.

[0063] Comparative Example 4: This comparative example is basically the same as Example 1, except that sodium hydroxide solution is added instead of hexamethylenetetramine solution.

[0064] The results show that after adding sodium hydroxide solution, the reaction rate is accelerated, and OH is released quickly. - , pH changes greatly, resulting in Ce 3+ Instantaneous precipitation and oxidation (Ce 3+ →Ce 4+ ), the reaction rate is greatly accelerated. The cerium ions in the solution that are not adsorbed by cellulose are quickly precipitated and cannot form cerium oxide nanoparticles inside the cellulose.

Claims

1. A bacterial cellulose aerogel modified with cerium oxide nanoparticles, a preparation method thereof, and its application in the field of gas filtration, characterized in that: The following steps are involved: Step 1: At room temperature, cut the bacterial cellulose gel film into 8*8*1cm 3 , washed several times in deionized water to remove other components; Step 2: Immerse the washed bacterial cellulose in Ce(NO3)2·6H2O solution; Step 3: Stirring was continued at room temperature for 1 h. During the stirring process, hexamethylenetetramine solution was added dropwise and the reaction time was continued. Step 4: After the reaction is completed, the mixture is washed with ultrapure water, frozen with liquid nitrogen, freeze-dried for 12 hours, and dried in a vacuum drying oven for 12 hours to obtain a bacterial cellulose aerogel composite material modified with cerium oxide nanoparticles; Step 5: Antibacterial and filtration tests were performed on the bacterial cellulose aerogel composite modified with cerium oxide nanoparticles.

2. The bacterial cellulose aerogel modified with cerium oxide nanoparticles and its preparation method, and its application in the field of gas filtration according to claim 1, characterized in that: In the step 2, Ce(NO3)2·6H2O solution is added to prepare a volume concentration of 0.1M.

3. The bacterial cellulose aerogel modified with cerium oxide nanoparticles and its preparation method, and its application in the field of gas filtration according to claim 1, characterized in that: In step 3, C6H 12 The volume concentration of N4 solution is 0.5~1M.

4. The bacterial cellulose aerogel modified with cerium oxide nanoparticles and its preparation method, and its application in the field of gas filtration according to claim 1, characterized in that: The continuous reaction time in step 3 is set to 6 to 24 hours.

5. The bacterial cellulose aerogel modified with cerium oxide nanoparticles and its preparation method, and its application in the field of gas filtration according to claim 1, characterized in that: In step 4, the freeze-drying temperature is -70°C, the drying time is 12 hours, and the atmospheric pressure is 0.05 Pa.

6. The bacterial cellulose aerogel modified with cerium oxide nanoparticles and its preparation method, and its application in the field of gas filtration according to claim 1, characterized in that: The vacuum drying temperature in step 4 and step 5 is 80° C. and the drying time is 12 h.

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