Green nano-zinc oxide antibacterial material and preparation method and application thereof

Abstract

The application relates to a green nano zinc oxide antibacterial material and a preparation method and application thereof, and the preparation method comprises the following steps: adding zinc acetate dihydrate into deionized water, adding konjac glucomannan and gum arabic under constant-temperature stirring, adding sodium hydroxide solution drop by drop to generate a precipitate, centrifuging and washing the precipitate, and drying; and the dried sample is calcined in a muffle furnace to prepare nano zinc oxide. The synthesized green nano zinc oxide has antibacterial effect, and the preparation process is simple, green, environment-friendly, and raw materials are easy to obtain, so the green nano zinc oxide can be used as a green antibacterial material.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of antibacterial and microbial inhibition technology, and particularly relates to a green nano zinc oxide antibacterial material and a preparation method and application thereof. BACKGROUND

[0002] Zinc oxide is an effective antibacterial agent and is widely used in food, medicine, materials, chemical industry and many other fields. Microorganisms widely exist in natural water bodies and can cause health problems in water environments, and are easily attached to metal surfaces to cause microbial corrosion. Sulfate-reducing bacteria are a common corrosive bacteria, and its metabolic product sulfide can react with copper, iron, zinc and other metals to cause serious corrosion of metals. Adding bactericides to water is the most common and effective means to inhibit microbial corrosion, but traditional bactericides often make microorganisms resistant, have unsatisfactory antibacterial effect, and easily cause environmental pollution, which does not conform to the concept of green development. Nano zinc oxide can be used as a new type of bactericide to inhibit microbial corrosion and is not easy to make microorganisms resistant.

[0003] In the preparation of nano zinc oxide, many studies use polyethylene glycol, polyvinyl alcohol, ethylenediamine, triethanolamine, tetraethylammonium bromide, glycine and other additives as end-capping agents to control the particle size and morphology of nano zinc oxide and enhance the antibacterial effect of zinc oxide. However, most of these additives are toxic and harmful chemicals, which will undoubtedly pollute the environment. SUMMARY

[0004] The purpose of the present application is to provide a green nano zinc oxide antibacterial material and a preparation method and application thereof, which are green and environmentally friendly.

[0005] The purpose of the present application can be achieved by the following technical solution: a preparation method of a green nano zinc oxide antibacterial material, comprising the following steps:

[0006] Step 1, adding zinc acetate dihydrate into deionized water;

[0007] Step 2, adding konjac glucomannan and gum arabic under constant temperature stirring;

[0008] Step 3, continuing constant temperature stirring and adding sodium hydroxide solution drop by drop;

[0009] Step 4, centrifuging the generated precipitate and cleaning it with anhydrous ethanol and deionized water;

[0010] Step 5, placing the cleaned precipitate into an oven for drying;

[0011] Step 6, placing the dried precipitate into a muffle furnace for calcination to prepare nano zinc oxide.

[0012] Arabic gum (AG) and konjac glucomannan (KGM) are natural polysaccharides extracted from plants, with large output and low price, which can replace traditional chemical agents as capping agents for controlling the synthesis of zinc oxide. Zn 2+ can react with AG and KGM to form [Zn(AG)] 2+ and [Zn(KGM)] 2+ , which react with OH - in alkaline solution to form [Zn(OH)2]AG and [Zn(OH)2]KGM, and ZnO after calcination at high temperature. The preparation method meets the standard requirements of environmental friendliness, and the prepared nano zinc oxide can effectively inhibit microbial activity and has bactericidal effect.

[0013] Preferably, the concentration of zinc acetate dihydrate in deionized water in step 1 is 0.01-0.5 mol / L.

[0014] Preferably, the stirring temperature in step 2 is 50-80℃, the stirring speed is 500-1000 rpm, and the stirring time is 10-40 min.

[0015] Preferably, the addition amount of konjac glucomannan and arabic gum in the zinc acetate solution in step 2 is 0.05-1.0 wt% and 0.05-1.0 wt%, respectively.

[0016] Preferably, the stirring speed in step 3 is 500-1000 rpm, 0.2-2.0 mol / L sodium hydroxide solution is added dropwise, the final pH is 9-11, and the holding time is 1-7 h.

[0017] Preferably, the centrifugal washing of nanoparticles in step 4 is performed at 5000-10000 rpm for 10-30 min.

[0018] Preferably, the drying temperature of nano zinc oxide in step 5 is 60-90℃, and the duration is 10-24 h.

[0019] Preferably, the calcination temperature of nano zinc oxide in step 6 is 350-450℃, and the calcination time is 1-3 h.

[0020] A green nano zinc oxide antibacterial material is prepared by the above preparation method.

[0021] The application of a green nano zinc oxide antibacterial material, the nano material is applied in an aqueous solution, which can effectively inhibit the growth of microorganisms and has good bactericidal performance.

[0022] The application of a green nano zinc oxide antibacterial material, the nano material is used to reduce the number of sulfate-reducing bacteria and inhibit their growth and reproduction.

[0023] Compared with the prior art, the application uses gum arabic and konjac glucomannan as capping agents for synthesizing nano zinc oxide, and uses the synthesis product as a bactericide. Taking sulfate-reducing bacteria as an example, the nano zinc oxide has a good bactericidal effect on the sulfate-reducing bacteria in an aqueous solution, and can further control microbial corrosion of metals. It is shown that the gum arabic and konjac glucomannan have application value as natural polysaccharides for preparing nano zinc oxide antibacterial materials. Compared with other synthesis processes of nano zinc oxide, the preparation process of the application is simple, low in cost, green and environment-friendly, has a good bactericidal effect, can be used as a green antibacterial material, and has a wide application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 It is a transmission electron microscope image of the nano zinc oxide antibacterial material obtained in Example 1 of the application.

[0025] Figure 2 It is an XRD image of the nano zinc oxide antibacterial material obtained in Example 1 of the application.

[0026] Figure 3 It is a bactericidal rate graph of the nano zinc oxide antibacterial material obtained in Example 1 of the application. DETAILED DESCRIPTION

[0027] The application will be described in detail below in combination with the drawings and specific examples. The following examples are implemented on the premise of the technical scheme of the application, and detailed implementation modes and specific operation processes are given, but the protection scope of the application is not limited to the following examples.

[0028] In the following examples, gum arabic (CAS: 9000-01-5) and konjac glucomannan (CAS: 37220-17-0) are purchased from Aldrich Reagent (Shanghai) Co., Ltd.

[0029] Example 1

[0030] Zinc acetate dihydrate is added to deionized water to a concentration of 0.1 mol / L, and 0.5 wt% konjac polysaccharide and 0.5 wt% gum arabic are added under constant stirring at 65℃. The solution is stirred at 800 rpm for 30 min. 1 mol / L sodium hydroxide solution is added dropwise to the solution until the pH is 11, and the stirring is continued at 800 rpm for 5 h after the dropwise addition is completed. The generated precipitate is centrifuged at 10000 rpm for 20 min, and washed with anhydrous ethanol and deionized water for more than 3 times. The centrifuged and washed precipitate is placed in an oven, and baked at 80℃ for 12 h. After drying, the precipitate is placed in a 400℃ muffle furnace for calcination for 2 h, and green nano zinc oxide antibacterial material is obtained.

[0031] The transmission electron microscope image of the nano zinc oxide antibacterial material obtained in the example is shown in Figure 1 The XRD image is shown in Figure 2The nano zinc oxide is mainly in a circular shape, and the particle size of the nano material is about 30 nm. The standard zinc oxide is a regular hexagon. The morphology of the nano particles changes after adding the gum arabic and the konjac glucomannan, indicating that the gum arabic and the konjac glucomannan molecules act as the capping agent and the stabilizer in the synthesis of the zinc oxide, and change the morphology and the particle size of the zinc oxide. The XRD pattern of the synthesized nano material is consistent with the standard card JCPDS NO. 80-0074 of the zinc oxide.

[0032] In this embodiment, the synthesized green zinc oxide nano material is added into the simulated water containing 10% of the sulfate reducing bacteria culture medium (composition: NaCl 7.5 mmol / L, NaHCO3 2.00 mmol / L, Na2SO4 3.50 mmol / L, MgSO4 0.25 mmol / L, CaCl2 0.50 mmol / L), and the bactericidal rate of the nano material is calculated by using the plate counting method, as shown in Table 1. Figure 3 After adding the nano zinc oxide, the sulfate reducing bacteria cells are damaged, and the number of the microorganisms is reduced. The greater the concentration of the added green zinc oxide nano material, the greater the bactericidal rate of the sulfate reducing bacteria. The bactericidal rates of the green nano zinc oxide with the concentrations of 10 mg / L, 20 mg / L, 50 mg / L and 100 mg / L on the sulfate reducing bacteria are 39.2%, 61.9%, 81.2% and 87.0% respectively, and the antibacterial effect is relatively significant.

[0033] Comparative Example 1

[0034] Zinc acetate dihydrate is added into the deionized water to a concentration of 0.1 mol / L. Under the constant stirring at 800 rpm and 65°C, 1 mol / L sodium hydroxide solution is added dropwise into the solution until the pH is 11. After the dropwise addition is completed, the stirring is continued at 800 rpm for 5 h. The generated precipitate is centrifuged at 10,000 rpm for 20 min, and washed with anhydrous ethanol and deionized water for more than 3 times. The centrifuged and washed precipitate is placed into an oven, and baked at 80°C for 12 h. After the baking, the precipitate is placed into a muffle furnace at 400°C for 2 h to obtain the nano zinc oxide.

[0035] In this comparative example, the synthesized zinc oxide nano material is added into the simulated water containing 10% of the sulfate reducing bacteria culture medium (composition: NaCl 7.5 mmol / L, NaHCO3 2.00 mmol / L, Na2SO4 3.50 mmol / L, MgSO4 0.25 mmol / L, CaCl2 0.50 mmol / L), and the bactericidal rate of the nano material is calculated by using the plate counting method, and the results are shown in Table 1.

[0036] Comparative Example 2

[0037] Zinc acetate dihydrate was added to deionized water to a concentration of 0.1 mol / L, 1 wt% konjac glucomannan was added under constant stirring at 800 rpm and 65°C, and stirred for 30 min. 1 mol / L sodium hydroxide solution was added dropwise to the solution until the pH was 11, and stirring was continued at 800 rpm for 5 h after the end of the dropwise addition. The resulting precipitate was centrifuged at 10,000 rpm for 20 min and washed with anhydrous ethanol and deionized water for more than 3 times. The centrifuged and washed precipitate was placed in an oven and baked at 80°C for 12 h. After drying, the precipitate was calcined in a muffle furnace at 400°C for 2 h to obtain nano-zinc oxide.

[0038] In this comparative example, the synthesized green zinc oxide nanomaterial was added to simulated water containing 10% sulfate-reducing bacteria medium (composition: NaCl 7.5 mmol / L, NaHCO3 2.00 mmol / L, Na2SO4 3.50 mmol / L, MgSO4 0.25 mmol / L, CaCl2 0.50 mmol / L), and the bactericidal rate of the nanomaterial was calculated by plate counting method. The results are shown in Table 1.

[0039] Comparative Example 3

[0040] Zinc acetate dihydrate was added to deionized water to a concentration of 0.1 mol / L, 1 wt% konjac glucomannan was added under constant stirring at 800 rpm and 65°C, and stirred for 30 min. 1 mol / L sodium hydroxide solution was added dropwise to the solution until the pH was 11, and stirring was continued at 800 rpm for 5 h after the end of the dropwise addition. The resulting precipitate was centrifuged at 10,000 rpm for 20 min and washed with anhydrous ethanol and deionized water for more than 3 times. The centrifuged and washed precipitate was placed in an oven and baked at 80°C for 12 h. After drying, the precipitate was calcined in a muffle furnace at 400°C for 2 h to obtain nano-zinc oxide.

[0041] In this comparative example, the synthesized green zinc oxide nanomaterial was added to simulated water containing 10% sulfate-reducing bacteria medium (composition: NaCl 7.5 mmol / L, NaHCO3 2.00 mmol / L, Na2SO4 3.50 mmol / L, MgSO4 0.25 mmol / L, CaCl2 0.50 mmol / L), and the bactericidal rate of the nanomaterial was calculated by plate counting method. The results are shown in Table 1.

[0042] Table 1 Bactericidal rate of nanomaterial

[0043] Nanomaterial concentration (mg / L) 10 20 50 100 Example 1 kill rate (%) 39.2 61.9 81.2 87.0 Comparative Example 1 kill rate (%) 32.4 50.8 69.6 77.9 Comparative Example 2 kill rate (%) 36.5 58.7 79.7 84.4 Comparative Example 3 kill rate (%) 35.1 55.6 75.4 80.5

[0044] From the results of Table 1, among the four kinds of nanomaterials, the bactericidal rate of Example 1 is the highest, and the bactericidal rate of Comparative Example 1 is the lowest. It is shown that the addition of gum arabic and konjac glucomannan can effectively enhance the antibacterial effect of zinc oxide nanomaterials. When a natural polysaccharide is added alone, the antibacterial effect of zinc oxide is enhanced, and the antibacterial performance of gum arabic as a capping agent for synthesizing zinc oxide is stronger than that of konjac glucomannan. When konjac glucomannan and gum arabic are added as capping agents at the same time, the antibacterial performance of zinc oxide is stronger than that of pure zinc oxide without adding a polysaccharide and adding only one kind of polysaccharide.

[0045] The present application successfully synthesizes green nano-zinc oxide antibacterial material by using gum arabic and konjac glucomannan through a green method. The synthesis method is simple, the cost is low, and the material is easy to obtain. The synthesized green nano-zinc oxide has good bacteriostatic effect on sulfate-reducing bacteria, and has wide application prospect.

[0046] The natural polysaccharide-synthesized zinc oxide nanomaterials have the characteristics of small volume, large surface area, good biocompatibility, low toxicity, good physical and chemical properties, and can be used for various biomedical applications. In addition, they are low in cost, easy to obtain, energy-saving and environmentally friendly. In addition to some nanomaterials that can be directly ingested in food, medicine and other fields, the use of nanomaterials in aqueous solution inevitably circulates into the human body through the ecosystem. The natural polysaccharide-synthesized zinc oxide nanomaterials have good biocompatibility and safety. The polysaccharide used in the synthesis process is natural, non-toxic and biodegradable, the synthesis process is green and environmentally friendly, does not produce toxic and harmful substances, the synthesized product is environmentally friendly and harmless to the human body, and has good antibacterial performance.

[0047] The above description of the embodiments is for the purpose of facilitating the understanding and use of the application by those skilled in the art. Those skilled in the art can easily make various modifications to these embodiments, and apply the general principles described herein to other embodiments without having to go through creative labor. Therefore, the present application is not limited to the above embodiments, and the improvements and modifications made by those skilled in the art without departing from the scope of the present application should be within the scope of protection of the present application.

Claims

1. A method for preparing green nano zinc oxide antibacterial material, characterized in that, The method comprises the following steps: Step 1, adding zinc acetate dihydrate into deionized water; Step 2, adding konjac glucomannan and gum arabic under constant temperature stirring; Step 3, continuously stirring under constant temperature, adding sodium hydroxide solution drop by drop; Step 4, centrifuging the generated precipitate, cleaning with anhydrous ethanol and deionized water; Step 5, drying the cleaned precipitate; Step 6, calcining the dried precipitate in a muffle furnace to prepare nano zinc oxide; The stirring temperature in Step 2 is 50-80℃, the rotating speed is 500-1000rpm, and the stirring lasts for 10-40min; The adding amount of konjac glucomannan and gum arabic in the zinc acetate solution in Step 2 is 0.05-1.0wt% and 0.05-1.0wt% respectively; The calcination temperature in Step 6 is 350-450℃, and the calcination time is 1-3h; The material prepared by the method is applied in aqueous solution to inhibit the growth of microorganisms; The material is used to reduce the number of sulfate-reducing bacteria and inhibit their growth and reproduction.

2. The preparation method of the green nano zinc oxide antibacterial material according to claim 1, characterized in that, The concentration of zinc acetate dihydrate in deionized water in Step 1 is 0.01-0.5mol / L.

3. The preparation method of the green nano zinc oxide antibacterial material according to claim 1, characterized in that, The rotating speed in Step 3 is 500-1000rpm, 0.2-2.0mol / L sodium hydroxide solution is added drop by drop, the final pH is 9-11, and it is kept for 1-7h.

4. The preparation method of the green nano zinc oxide antibacterial material according to claim 1, characterized in that, The centrifugation in Step 4 is carried out at 5000-10000rpm for 10-30min.

5. The method of claim 1, wherein the green nano-zinc oxide antibacterial material is prepared by the following steps: (1) preparing a zinc oxide precursor; (2) mixing the zinc oxide precursor with a reducing agent to obtain a green nano-zinc oxide antibacterial material. The drying temperature in Step 5 is 60-90℃, and the duration is 10-24h.

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