Preparation of silver-based MOFs loaded nano-silver antibacterial material and application of silver-based MOFs loaded nano-silver antibacterial material in tobacco flavoring essence

Abstract

The invention discloses preparation of a silver-based MOFs loaded nano-silver antibacterial material and application of the silver-based MOFs loaded nano-silver antibacterial material in tobacco charging essence, and a preparation method of the silver-based MOFs loaded nano-silver antibacterial material comprises the following steps: ultrasonically dispersing silver nitrate and 3-phosphoric acid in a mixed solution of dimethylformamide and dimethyl sulfoxide, transferring to a high-pressure reaction kettle, heating to obtain a gray black solid, centrifugally washing and drying to obtain a silver-based MOFs loaded nano-silver antibacterial material; the silver-based MOFs composite material is obtained; dissolving AOT in heptane to prepare an AOT solution; uniformly dividing the AOT solution into two parts; adding a silver-based MOFs composite material into one part, dropwise adding a silver nitrate aqueous solution, and stirring to form a silver nitrate microemulsion; dropwise adding a hydrazine hydrate solution into the other part of AOT to form a microemulsion; slowly dropwise adding the micro-emulsion containing hydrazine hydrate into the silver nitrate micro-emulsion to obtain a bright yellow transparent solution; and centrifugally filtering and drying to obtain the silver-based MOFs loaded nano-silver antibacterial material. The antibacterial material is used for performing rapid cold sterilization treatment on the added essence, the operation is simple, the efficiency is high, the green effect is realized, the repeated use can be realized, and the quality of the treated added essence is unchanged and stable.

Description

Technical Field

[0001] The invention relates to the technical field of tobacco, and in particular to the preparation of a silver-based MOFs-loaded nano-silver antibacterial material and its application in tobacco flavoring. Background Art

[0002] Tobacco flavorings are commonly known as sugar materials. They mainly use water as a solvent system. Their main ingredients are invert sugar and natural extracts. They are prone to fermentation, mildew, bubbles and other deterioration phenomena, and have become a potential threat to the stability of cigarette products. Microbial contamination is the main cause of spoilage of flavorings. The sources of microbial contamination in flavorings are diverse. Air, water, processing machinery and equipment, and flavor raw materials may all be sources of contaminated microorganisms. Flavorings are heat-sensitive products. Excessive temperature will change the color and flavor of flavorings. Therefore, non-heating sterilization technology / low-temperature long-time cold sterilization technology is used to ensure product quality without changing the product flavor.

[0003] At present, antimicrobial agents are mainly divided into three categories. The first category is metals such as Ag, Cu and Hg, as well as inorganic antimicrobial agents such as TiO2 and ZnO; the second category is organic antimicrobial agents such as quaternary ammonium salts, guanidines and halogenated phenols; the third category is natural antimicrobial agents such as chitosan, peptides and phenols extracted from animals and plants. Among them, inorganic antimicrobial agents have a series of advantages such as broad-spectrum antimicrobial, high temperature resistance, and strong durability, and are widely used in various fields such as food and medicine. + The bactericidal ability of nanosilver (AgNPs) is more than 200 times that of micron-sized silver. + and produce reactive oxygen species (ROS) to kill bacteria, which is more effective than Ag + It has a longer-lasting bactericidal effect and is a research hotspot in the field of antimicrobial agents.

[0004] However, due to its small particle size, AgNPs are prone to agglomeration when there is a lack of active agents or stabilizers on the surface, and cannot exert good antibacterial activity. Therefore, it is necessary to compound nanosilver with a variety of antibacterial agents and carriers through physical adsorption or chemical grafting to improve its dispersibility. MOFs is a porous crystalline material, a grid-structured crystal formed by the coordination of metal ions or metal clusters with organic ligands, so it is also called a porous coordination polymer. It has a higher specific surface area than perforated materials and a larger pore size than microporous materials, and can carry large molecules.

[0005] Therefore, the present invention aims to provide a MOFs-loaded nanosilver antibacterial material and a preparation method thereof to address the problem that silver nanoparticles tend to spontaneously aggregate into large particles and fail to play an effective role, thus affecting their antibacterial properties. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a preparation method of a silver-based MOFs-loaded nanosilver antibacterial material and its application in tobacco flavorings, and to apply the material to tobacco flavorings for sterilization treatment, which has the characteristics of simple operation, high efficiency, greenness, and reusability, and the quality of the flavorings remains unchanged and stable after treatment.

[0007] The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0008] A method for preparing a silver-based MOFs-loaded nanosilver antibacterial material comprises the following steps:

[0009] (1) Preparation of silver-based MOFs materials: Silver nitrate and 3-phosphobenzoic acid were ultrasonically dispersed in a mixed solution of dimethylformamide and dimethyl sulfoxide, transferred to a high-pressure reactor, heated to 160-180°C and maintained for 8-10 hours, and then naturally cooled to room temperature. The obtained gray-black solid was centrifuged, washed with 95% ethanol, and vacuum dried to obtain a silver-based MOFs composite material;

[0010] (2) Preparation of silver-based MOFs loaded with nanosilver materials:

[0011] 21) dissolving sodium diisooctyl sulfosuccinate (AOT) in heptane to prepare an AOT solution of a certain concentration;

[0012] 22) Stir at high speed on a magnetic stirrer for 20 min at room temperature and divide the AOT solution into two equal parts;

[0013] 23) adding the silver-based MOFs composite material of step (1) to one solution, and dropping a silver nitrate aqueous solution, and then continuously stirring for 30 minutes to form a silver nitrate microemulsion;

[0014] 24) Add hydrazine hydrate solution dropwise to another portion of AOT solution and stir at high speed for 30 min to form a microemulsion;

[0015] 25) Slowly drop the microemulsion containing hydrazine hydrate into the silver nitrate microemulsion stirred at a low speed. After the dropwise addition is completed, continue stirring for 2 hours to obtain a stable bright yellow transparent solution;

[0016] 26) centrifugally filter and wash with 95% ethanol, and vacuum dry to obtain silver-based MOFs-loaded nanosilver antibacterial material.

[0017] Preferably, in the above technical solution, the molar ratio of silver nitrate to 3-phosphobenzoic acid is 1:1 to 2:1; the molar ratio of dimethylformamide to dimethyl sulfoxide is 2:1 to 3:1.

[0018] Preferably, in the above technical solution, in step (1), the mixture is transferred to the high-pressure reactor and heated at a rate of 3 to 5°C / min.

[0019] Preferably, in the above technical solution, in step (2), the molar ratio of hydrazine hydrate to silver nitrate is 3:1 to 4:1; and the mass ratio of the silver-based MOFs material to silver nitrate is 2:1 to 4:1.

[0020] Preferably, in the above technical solution, in step (2), the concentration of sodium diisooctyl sulfosuccinate is controlled at (0.1-0.2) mol / L.

[0021] A silver-based MOFs-loaded nanosilver antibacterial material, characterized in that the silver-based MOFs-loaded nanosilver antibacterial material is prepared according to the above-mentioned preparation method.

[0022] A method for sterilizing tobacco flavoring essence by using the silver-based MOFs loaded nano-silver antibacterial material, comprising the following steps:

[0023] S1. Prepare the added flavor according to the formula requirements of the cigarette flavor and fragrance product, pour the prepared added flavor into the stirring kettle and stir continuously for 30 minutes;

[0024] S2, silver-based MOFs loaded nanosilver materials are filled into a homemade filter box, and the filter box is connected to the discharge pipeline port of the stirring tank;

[0025] S3. After the stirring is completed, open the discharge valve at the bottom of the stirring kettle, add the flavoring agent and pour it into the product packaging barrel through the filter box and seal it for storage.

[0026] An application of the silver-based MOFs-loaded nano-silver antibacterial material in tobacco flavoring.

[0027] The above technical solution of the present invention has the following beneficial effects:

[0028] The present application provides a silver-based MOFs-loaded nanosilver antibacterial material, and uses the antibacterial material to perform rapid cold sterilization treatment on added flavors to extend the shelf life of the added flavors and prevent mildew and deterioration; the material has the characteristics of simple operation, high efficiency, greenness, and reusability, and the quality of the added flavors remains unchanged and stable after treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

[0030] Figure 1 This is a schematic diagram of the use status of the silver-based MOFs-loaded nanosilver antibacterial material of the present application.

[0031] Figure 2 Comparison of sterilization effects of the products in the examples. DETAILED DESCRIPTION

[0032] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention unless otherwise specifically stated.

[0033] Unless otherwise specified, the reagents used in this application are all commercially available or obtained through commercial channels, or can be prepared by referring to existing chemical methods.

[0034] Example 1

[0035] A method for preparing a silver-based MOFs-loaded nanosilver antibacterial material comprises the following steps:

[0036] (1) Preparation of silver-based MOFs materials:

[0037] Silver nitrate and 3-phosphobenzoic acid were ultrasonically dispersed in a mixed solution of dimethylformamide and dimethyl sulfoxide; the mixture was transferred to a high-pressure reactor and heated to 160°C at a rate of 3°C / min and maintained for 10 hours, and then naturally cooled to room temperature. The obtained gray-black solid was centrifuged, washed with 95% ethanol, and vacuum dried to obtain a silver-based MOFs composite material;

[0038] Wherein, the molar ratio of silver nitrate to 3-phosphobenzoic acid is 1:1; the molar ratio of dimethylformamide to dimethyl sulfoxide is 2:1.

[0039] (2) Preparation of silver-based MOFs loaded with nanosilver materials:

[0040] Dissolve sodium diisooctyl sulfosuccinate (AOT) in heptane to prepare an AOT solution of a certain concentration, wherein the concentration of sodium diisooctyl sulfosuccinate is controlled at 0.1 mol / L;

[0041] Stir at high speed on a magnetic stirrer for 20 min at room temperature and divide the AOT solution into two equal parts;

[0042] In one solution, silver-based MOFs material and silver nitrate aqueous solution were added dropwise, and then stirred for 30 minutes to form a silver nitrate microemulsion; wherein the mass ratio of silver-based MOFs material to silver nitrate was 2:1;

[0043] In another portion of the AOT solution, hydrazine hydrate solution was added dropwise and stirred at high speed for 30 minutes to form a microemulsion; wherein the molar ratio of hydrazine hydrate to silver nitrate was 3:1.

[0044] The microemulsion containing hydrazine hydrate is slowly added dropwise to the silver nitrate microemulsion stirred at a low speed. After the addition is completed, stirring is continued for 2 hours to obtain a stable bright yellow transparent solution;

[0045] The silver-based MOFs were loaded with nanosilver materials after centrifugal filtration and washing with 95% ethanol and vacuum dried.

[0046] Sterilization treatment in tobacco flavorings:

[0047] S1. Prepare the added flavor according to the formula requirements of the cigarette flavor and fragrance product, pour the prepared added flavor into the stirring kettle and stir continuously for 30 minutes;

[0048] S2. Silver-based MOFs loaded nanosilver materials are filled into a homemade filter box, and the filter box is connected to the outlet pipeline port of the stirred tank (such as Figure 1 );

[0049] S3. After the stirring is completed, open the discharge valve at the bottom of the stirring kettle, and pour the added flavor into the product packaging barrel through the filter box and seal it for storage. Take a sample and mark it as added flavor 1#.

[0050] Example 2

[0051] A method for preparing a silver-based MOFs-loaded nanosilver antibacterial material comprises the following steps:

[0052] (1) Preparation of silver-based MOFs materials:

[0053] Silver nitrate and 3-phosphobenzoic acid were ultrasonically dispersed in a mixed solution of dimethylformamide and dimethyl sulfoxide, transferred to a high-pressure reactor and heated to 180°C at a rate of 5°C / min and maintained for 10 hours, then naturally cooled to room temperature to obtain a gray-black solid, which was centrifuged, washed with 95% ethanol, and vacuum dried to obtain a silver-based MOFs composite material; wherein the molar ratio of silver nitrate to 3-phosphobenzoic acid was 2:1; the molar ratio of dimethylformamide to dimethyl sulfoxide was 2:1.

[0054] (2) Preparation of silver-based MOFs loaded with nanosilver materials:

[0055] Dissolve sodium diisooctyl sulfosuccinate (AOT) in heptane to prepare an AOT solution of a certain concentration, wherein the concentration of sodium diisooctyl sulfosuccinate is controlled at 0.2 mol / L;

[0056] Stir at high speed on a magnetic stirrer for 20 min at room temperature and divide the AOT solution into two equal parts;

[0057] A silver-based MOFs material is added to a solution and a silver nitrate aqueous solution is added dropwise, and then stirred for 30 minutes to form a microemulsion; wherein the mass ratio of the silver-based MOFs material to the silver nitrate is 3:1;

[0058] Add hydrazine hydrate solution dropwise to another portion of AOT solution and stir at high speed for 30 minutes to form a silver nitrate microemulsion; wherein the molar ratio of hydrazine hydrate to silver nitrate is 4:1;

[0059] The microemulsion containing hydrazine hydrate is slowly added dropwise to the silver nitrate microemulsion stirred at a low speed. After the addition is completed, stirring is continued for 2 hours to obtain a stable bright yellow transparent solution;

[0060] The silver-based MOFs were loaded with nanosilver materials after centrifugal filtration and washing with 95% ethanol and vacuum dried.

[0061] Sterilization treatment in tobacco flavorings:

[0062] S1. Prepare the Red Flag Canal (New Galaxy) (provided by Henan China Tobacco Zhumadian Cigarette Factory) flavoring essence according to the formula requirements of cigarette flavors and fragrances, and pour the prepared flavoring essence into a stirring kettle and continue stirring for 30 minutes;

[0063] S2. Silver-based MOFs loaded nanosilver materials are filled into a homemade filter box, and the filter box is connected to the outlet pipeline port of the stirred tank (such as Figure 1 );

[0064] S3. After the stirring is completed, open the discharge valve at the bottom of the stirring kettle, and pour the added flavor into the product packaging barrel through the filter box and seal it for storage. Take a sample and mark it as added flavor 2#.

[0065] Example 3

[0066] A method for preparing a silver-based MOFs-loaded nanosilver antibacterial material comprises the following steps:

[0067] (1) Preparation of silver-based MOFs materials:

[0068] Silver nitrate and 3-phosphobenzoic acid were ultrasonically dispersed in a mixed solution of dimethylformamide and dimethyl sulfoxide, transferred to a high-pressure reactor and heated to 160°C at a rate of 5°C / min and maintained for 10 hours, then naturally cooled to room temperature to obtain a gray-black solid, which was centrifuged, washed with 95% ethanol, and vacuum dried to obtain a silver-based MOFs composite material; wherein the molar ratio of silver nitrate to 3-phosphobenzoic acid was 2:1; the molar ratio of dimethylformamide to dimethyl sulfoxide was 3:1.

[0069] (2) Preparation of silver-based MOFs loaded with nanosilver materials:

[0070] Dissolve sodium diisooctyl sulfosuccinate (AOT) in heptane to prepare an AOT solution of a certain concentration, wherein the concentration of sodium diisooctyl sulfosuccinate is controlled at 0.1 mol / L;

[0071] Stir at high speed on a magnetic stirrer for 20 min at room temperature and divide the AOT solution into two equal parts;

[0072] A silver-based MOFs material is added to a solution and a silver nitrate aqueous solution is added dropwise, and then stirred for 30 minutes to form a silver nitrate microemulsion; wherein the mass ratio of the silver-based MOFs material to the silver nitrate is 4:1;

[0073] Add hydrazine hydrate solution dropwise to another portion of AOT solution and stir at high speed for 30 minutes to form a microemulsion; wherein the molar ratio of hydrazine hydrate to silver nitrate is 4:1;

[0074] The microemulsion containing hydrazine hydrate was slowly added dropwise to the silver nitrate microemulsion stirred at a low speed. After the addition was completed, stirring was continued for 2 hours to obtain a stable bright yellow transparent solution. The solution was centrifuged and washed with 95% ethanol and vacuum dried to obtain the silver-based MOFs loaded with nanosilver material.

[0075] Sterilization treatment in tobacco flavorings:

[0076] S1. Prepare the Red Flag Canal (New Galaxy) (provided by Henan China Tobacco Zhumadian Cigarette Factory) flavoring essence according to the formula requirements of cigarette flavors and fragrances, and pour the prepared flavoring essence into a stirring kettle and continue stirring for 30 minutes;

[0077] S2. Silver-based MOFs loaded nanosilver materials are filled into a homemade filter box, and the filter box is connected to the outlet pipeline port of the stirred tank (such as Figure 1 );

[0078] S3. After the stirring is completed, open the discharge valve at the bottom of the stirring kettle, and pour the added flavor into the product packaging barrel through the filter box and seal it for storage. Take a sample and mark it as added flavor 3#.

[0079] Of course, the added flavors of the present application may also adopt the flavor and fragrance formula of the heated cigarette formula commonly used in the art, and are not limited to the above-mentioned products. The present application only uses this as an example for experimental description.

[0080] Refer to "GB4789.2-2016 National Food Safety Standard Food Microbiology Test Total Colony Count Determination". Use NA medium to culture bacteria and dilute the sample to 1*10 -1 , take 100uL of each sample gradient to the plate, spread it evenly, and culture it at 37℃ for 72h.

[0081] The results are as follows Figure 2 As shown in the figure: after being sterilized by silver-based nanomaterials, the total number of colonies in flavors 1#, 2# and 3# decreased significantly, while the total number of colonies in untreated flavors was higher. This shows that silver-based MOFs loaded with nanosilver antibacterial materials can effectively eliminate bacteria in flavors, extend the shelf life of flavors, and ensure the stability of the quality of flavors.

[0082] Although the present invention has been disclosed as above by the embodiments, it is not intended to limit the present invention. Any person skilled in the art may make various choices and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention is limited by the claims and their equivalents.

Claims

1. A method for preparing a silver-based MOFs-loaded nanosilver antibacterial material, characterized in that: The following steps are involved: (1) Preparation of silver-based MOFs materials: Silver nitrate and 3-phosphobenzoic acid were ultrasonically dispersed in a mixed solution of dimethylformamide and dimethyl sulfoxide, transferred to a high-pressure reactor, heated to 160-180°C and maintained for 8-10 hours, and then naturally cooled to room temperature. The obtained gray-black solid was centrifuged, washed with 95% ethanol, and vacuum dried to obtain a silver-based MOFs composite material; (2) Preparation of silver-based MOFs loaded with nanosilver materials: 21) dissolving sodium diisooctyl sulfosuccinate (AOT) in heptane to prepare an AOT solution of a certain concentration; 22) Stir at high speed on a magnetic stirrer for 20 min at room temperature and divide the AOT solution into two equal parts; 23) adding the silver-based MOFs composite material of step (1) to one solution, and dropping a silver nitrate aqueous solution, and then continuously stirring for 30 minutes to form a silver nitrate microemulsion; 24) Add hydrazine hydrate solution dropwise to another portion of AOT solution and stir at high speed for 30 min to form a microemulsion; 25) Slowly drop the microemulsion containing hydrazine hydrate into the silver nitrate microemulsion stirred at a low speed. After the dropwise addition is completed, continue stirring for 2 hours to obtain a stable bright yellow transparent solution; 26) centrifugally filter and wash with 95% ethanol, and vacuum dry to obtain silver-based MOFs-loaded nanosilver antibacterial material.

2. The method for preparing the silver-based MOFs-loaded nanosilver antibacterial material according to claim 1, characterized in that: In step (1), the molar ratio of silver nitrate to 3-phosphobenzoic acid is 1:1 to 2:1; the molar ratio of dimethylformamide to dimethyl sulfoxide is 2:1 to 3:

1.

3. AgNP according to claim 1 S -(SBA-15) molecular sieve antibacterial material preparation method, characterized in that, In step (1), the mixture is transferred to a high pressure reactor and heated at a rate of 3 to 5°C / min.

4. The method for preparing the silver-based MOFs-loaded nanosilver antibacterial material according to claim 1, characterized in that: In step (2), the molar ratio of hydrazine hydrate to silver nitrate is 3:1 to 4:1; and the mass ratio of the silver-based MOFs material to silver nitrate is 2:1 to 4:

1.

5. The method for preparing the silver-based MOFs-loaded nanosilver antibacterial material according to claim 1, characterized in that: In step (2), the concentration of sodium diisooctyl sulfosuccinate is controlled at (0.1-0.2) mol / L.

6. A silver-based MOFs-loaded nanosilver antibacterial material, characterized in that: The silver-based MOFs-loaded nanosilver antibacterial material is prepared according to any one of the preparation methods described in claims 1-5.

7. A method for sterilizing tobacco flavorings using the silver-based MOFs-loaded nanosilver antibacterial material of claim 6, characterized in that: The following steps are involved: S1. Prepare the added flavor according to the formula requirements of the cigarette flavor and fragrance product, pour the prepared added flavor into the stirring kettle and stir continuously for 30 minutes; S2, silver-based MOFs loaded nanosilver materials are filled into a homemade filter box, and the filter box is connected to the discharge pipeline port of the stirring tank; S3. After the stirring is completed, open the discharge valve at the bottom of the stirring kettle, add the flavoring agent and pour it into the product packaging barrel through the filter box and seal it for storage.

8. Use of the silver-based MOFs-loaded nanosilver antibacterial material according to claim 6 in tobacco flavoring.

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