CN111978595A - Environment-friendly silver-loaded antibacterial agent based on plant waste powder and preparation method thereof - Google Patents

Abstract

The invention relates to an environment-friendly silver-carrying antibacterial agent based on plant waste powder and a preparation method thereof. It can be obtained by adding a certain proportion of plant waste powder, silver salt and silane coupling agent and mixing uniformly, and controlling the reaction temperature and time. The invention utilizes the rich reducing groups and porous structures of plant waste, and is designed so that silver ions are uniformly adsorbed under the action of the porous structures, and nano-silver is grown in-situ under the action of the reducing groups. The porous structure is evenly anchored inside and on the surface of the plant tissue, and the preparation of the silver-loaded antibacterial agent is realized in one step during the drying process of the plant waste powder. The invention solves the problems of high cost of nano-silver, easy agglomeration, easy dissolution of silver ions, weak interaction with macromolecular materials, and the like. The plant waste powder is used as the base, which is environmentally friendly, easy to obtain, low in cost, and conforms to the concept of sustainable development. The preparation process is simple, and the extra use of special equipment, reagents, especially reducing agents is avoided.

Description

A kind of environment-friendly silver-carrying antibacterial agent based on plant waste powder and preparation method thereof

technical field

The invention relates to the technical field of preparation of inorganic nanomaterials, in particular to an antibacterial agent and a preparation method thereof, in particular to an environment-friendly silver-carrying antibacterial agent based on plant waste powder and a preparation method thereof.

Background technique

With the improvement of people's health and safety awareness and demand, materials with antibacterial functions have attracted more and more attention. Giving a material antibacterial properties can improve its durability and extend its life to some extent. In addition, the high-efficiency antibacterial properties can also meet the functional requirements of health and harmlessness, and broaden the application field of the material. Therefore, the development of antibacterial agents has become a new industry. There are many kinds of antibacterial agents, which can be divided into two categories: inorganic antibacterial agents and organic antibacterial agents according to different chemical components. Although organic antibacterial agents have significant antibacterial effects in a short period of time, they have shortcomings such as poor persistence, high toxicity, volatile and easy decomposition, which limit the processing of materials. In contrast, inorganic antibacterial agents have outstanding long-term efficacy and good heat resistance, and can be widely used to prepare polymer composites with antibacterial functions.

Nano-silver antibacterial agent is a representative of inorganic antibacterial agent. It has the advantages of low toxicity, high efficiency, broad spectrum, durability, and no drug resistance, and has an advantage in the market and antibacterial field. However, nano-silver antibacterial agents have high surface energy and are easily aggregated to form large-sized particles, thereby reducing their dispersibility and antibacterial efficiency. In addition, the nano-silver antibacterial agent is easy to dissolve silver ions, and its release will shorten the antibacterial validity period. In addition, a large number of nano-silver antibacterial agents are used, which increases the cost and causes the enrichment of silver in the ecological environment. In order to solve the above-mentioned problems, existing researches uniformly anchor the nano-silver on a certain substrate, so as to obtain a silver-loaded antibacterial agent with better benefits. For example, the patent document CN105532731B discloses a preparation method of a slow-release zirconium phosphonate silver-loaded antibacterial agent. The specific method is to use zirconium phosphonate as a base, and vortex to load silver ions after radiation cross-linking modification with chitosan. , so as to obtain the target antibacterial agent, but the process of this method is complicated, time-consuming, and the scale is limited. Patent document CN106172386A discloses a preparation method of a silver-loaded shell powder antibacterial agent. The specific method is to mix natural shell powder with sodium citrate solution and silver salt solution, and reduce with a reducing agent sodium borohydride solution to obtain silver-loaded shell powder. Although the method is based on the natural, easily available and environmentally friendly animal carapace, an additional reducing agent is required, and the preparation of the shell powder requires anaerobic calcination, and the process is complicated. Patent document CN111202091A discloses a method for preparing a silver-loaded mesoporous silica antibacterial material. The specific method uses tannic acid as a non-surfactant template to prepare mesoporous silica, and simultaneously reduces silver ions to generate nano-silver. Although this method has mild conditions and does not use toxic reagents, it involves the preparation of mesoporous silica substrates, and the preparation method is complicated. Patent document CN107312315B discloses a preparation method of a lignin/silver composite antibacterial agent. The method loads silver on lignin, which overcomes the defects of poor stability, short efficacy and high cost of silver-based antibacterial agents. It needs to be separated and extracted from plants or papermaking waste liquid, and concentrated acid, concentrated alkali or organic solvent needs to be used in the process, which increases the risk of environmental pollution, and this method requires carboxylation modification of lignin, which involves a lot of pH adjustment. The process is complicated. Patent document CN109997871A discloses a one-step method of nano-silver-loaded hydrothermal carbon spheres and a preparation method thereof. The specific method is to remove impurities from all components of the collected biomass, wash and dry them, and then under the mechanical external force of a pulverizer and a ball mill Prepare into fine particles, and then dissolve the entire biomass components in a sodium hydroxide/urea system at low temperature. After dissolving, drop in the prepared silver ammonia solution to mix evenly, and pour the mixed solution into a high temperature The hydrothermal reaction is carried out in the autoclave, and after the reaction is completed, the hydrothermal carbon spheres loaded with nano-silver are obtained by centrifugation, washing, ultrasonication, centrifugation and freeze drying. Although this method solves the problems of easy agglomeration and instability of nano-silver, and also makes full use of biomass waste and the reducing groups contained in it, the process involved is complicated, and it not only needs to use sodium hydroxide/urea to dissolve biomass, It involves operations such as centrifugation, washing and sonication, and needs to react under high temperature and high pressure, and the reaction conditions require a temperature higher than 210 °C.

SUMMARY OF THE INVENTION

In view of the problems of high cost, easy agglomeration and easy dissolution of silver ions of the current nano-silver antibacterial agent, it also overcomes the weak interaction between the nano-silver and the substrate in the existing silver-loaded antibacterial agent preparation technology, and the complex process and reagents (especially the need for additional reducing agents) In view of the disadvantages of complicated substrate preparation and high risk of environmental pollution, the present invention provides a silver-loaded antibacterial agent based on plant waste powder and a preparation method thereof. The plant waste substrate used in this method is rich in plant transport tissue, has a porous structure and a large specific surface area, which is conducive to the growth and uniform loading of nano-scale functional particles. Meanwhile, the porous structure is beneficial to slow down the release of nanoparticles. In terms of chemical composition, cellulose, hemicellulose, lignin and widely existing plant polyphenols in plant waste are rich in highly reducible groups such as alcoholic hydroxyl groups, phenolic hydroxyl groups and sulfhydryl groups, which can be used as nano-silver The in situ growth and anchoring provide sites, avoiding the additional use of reducing agents.

The method is based on natural, easily available and environmentally friendly plant waste powder, and considering the rich reducing groups and porous structure in it, it is designed so that silver ions can be uniformly adsorbed under the action of the porous structure. Nano-silver can be grown by in situ reduction, and at the same time, nano-silver can be evenly anchored inside and on the surface of plant tissue by means of the porous structure. Technologically, it is designed to simultaneously achieve the in-situ growth and anchoring of nanosilver during the drying process of plant waste powder, and the surface treatment of the resulting antibacterial agent. The method solves the problems of high cost of nano-silver, easy agglomeration and easy dissolution of silver ions, and the selected substrate is environmentally friendly and easy to obtain, low in cost, waste utilization conforms to the concept of sustainable development, and the preparation process does not require special equipment. The additional use of reducing agent in the preparation technology of the existing silver-loaded antibacterial agent is avoided.

The purpose of this invention is to realize through the following technical solutions:

The invention provides a preparation method of a silver-loaded antibacterial agent based on plant waste powder, comprising the following steps:

The plant waste is pulverized and ground into powder to obtain plant waste powder;

In parts by weight, 5-40 parts of silver salt are dissolved in water, 50-90 parts of plant waste powder and 1-12 parts of silane coupling agent are added in sequence, and after uniform stirring, light absorption is avoided, and drying is obtained to obtain a plant-based waste product. Silver-loaded antibacterial agent for powder.

Preferably, the plant waste includes one or a mixture of crop straws, waste wood, and plant husks.

Preferably, the silver salt includes one of silver nitrate, silver acetate or a mixture thereof.

Preferably, one end of the molecular structure of the silane coupling agent can interact with groups in the plant waste, and the other end can interact with nanoparticles.

Preferably, the silane coupling agent includes γ-aminopropyltriethoxysilane, γ-glycidyloxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, ethylene triethoxysilane, vinyltrimethoxysilane, vinyltris(β-methoxyethoxy)silane, γ-mercaptopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, One of N-(β-aminoethyl)-γ-aminopropyltrimethyl(eth)oxysilane, N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane or several mixtures.

Preferably, the time of the light-proof adsorption is 10-200 min.

Preferably, the drying time is 10-36h, and the temperature is 60-120°C.

Preferably, the particle size range of the plant waste powder is 40-600 mesh.

The present invention also provides a silver-loaded antibacterial agent based on plant waste powder, comprising the following components in parts by weight:

5-40 parts of silver salt; 50-90 parts of plant waste powder; 1-12 parts of silane coupling agent.

Preferably, the plant waste comprises one or a mixture of crop straws, waste wood, and plant husks;

Described silver salt comprises one in silver nitrate, silver acetate or their mixture;

One end of the molecular structure of the silane coupling agent can interact with groups in the plant waste, and the other end can interact with nanoparticles;

The silane coupling agent includes γ-aminopropyltriethoxysilane, γ-glycidyloxypropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, vinyltriethylsilane Oxysilane, vinyltrimethoxysilane, vinyltris(β-methoxyethoxy)silane, γ-mercaptopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, N-( One or more of β-aminoethyl)-γ-aminopropyltrimethyl(eth)oxysilane, N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane mixture.

The silver-loaded antibacterial agent based on plant waste powder prepared by the invention solves the problems of high cost of nano-silver, easy agglomeration and easy dissolution of silver ions, and no additional reducing agent is used.

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

1. In the aspect of the preparation process of the present invention, the loading of nano-silver is directly realized in one step in the drying process of the plant waste powder, and the process is simple, environmentally friendly, low-cost, and can be produced on a large scale. Existing methods require the use of complex equipment and even use toxic reagents.

2. In terms of substrate selection, the present invention uses plant waste powder as a carrier, the raw materials are readily available, rich in variety, natural and harmless, low in cost, green and environmentally friendly, and waste utilization conforms to the concept of sustainable development. However, most of the carriers used in the existing methods need to be synthesized and prepared separately, which not only complicates the process, but also increases the risk of environmental pollution.

3. In terms of conception, the present invention not only realizes the in-situ growth, uniform loading and slow release of nano-silver by utilizing the rich reducing groups and porous structures of plant waste, but also enables the loading of nano-silver, the drying of antibacterial agents and the The three-in-one surface treatment simplifies the process flow and can be applied to polymer materials after surface treatment with a silane coupling agent. Although the existing method can achieve uniform dispersion of nano-silver, its growth requires additional reducing agent, and the process is complicated.

Description of drawings

Other features, objects and advantages of the present invention will become more apparent by reading the detailed description of non-limiting embodiments with reference to the following drawings:

Fig. 1 is the scanning electron microscope image of the antibacterial agent obtained in Example 1 and Comparative Example 1; wherein, Fig. 1(a) is the antibacterial agent obtained in Comparative Example 1; Fig. 1(b) is the antibacterial agent obtained in Example 1;

Fig. 2 is the EDS collection of illustrative plates of the antibacterial agent obtained in Example 1;

3 is the XRD pattern of the antibacterial agent obtained in Example 1.

Detailed ways

The present invention will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that, for those skilled in the art, several changes and improvements can be made without departing from the inventive concept. These all belong to the protection scope of the present invention.

Example 1

The plant waste (bamboo and wood) is pulverized and ground into powder to obtain 200 mesh plant waste powder. In parts by weight, 27 parts of silver nitrate was dissolved in water, 63 parts of plant waste powder (bamboo and wood powder) and 10 parts of γ-aminopropyl triethoxysilane were added in turn, and the mixture was stirred evenly and absorbed in the dark for 100 minutes. It was then dried in an oven at 90 °C for 24 h to obtain a silver-loaded antibacterial agent based on plant waste powder. The results show that the nano-silver is uniformly dispersed on the plant waste powder, the average particle size of the nano-silver is about 14.0 nm, and the interface between the nano-silver and the substrate is blurred, and the two have strong interaction. The antibacterial rates of the prepared silver-loaded antibacterial agent against Escherichia coli and Staphylococcus aureus are 98% and 96% respectively (the antibacterial performance test standard is GB/T 21510-2008).

Example 2

The plant waste (coconut shell) is pulverized and ground into powder to obtain 100 mesh plant waste powder. In parts by weight, dissolve 5 parts of silver acetate in water, add 90 parts of plant waste powder (coconut shell powder) and 5 parts of γ-glycidyl ether oxypropyltrimethoxysilane in turn, stir evenly and avoid light absorption 10min, and then placed in an oven at 60° C. to dry for 36h to obtain a silver-loaded antibacterial agent based on plant waste powder.

After testing, the nano-silver is uniformly dispersed on the plant waste powder, and the average particle size of the nano-silver is about 16.8nm. The antibacterial rates of the prepared silver-loaded antibacterial agent against Escherichia coli and Staphylococcus aureus are 97% and 94% respectively (the antibacterial performance test standard is GB/T 21510-2008).

Example 3

The plant waste (wheat straw) was pulverized and ground into powder to obtain 40 mesh plant waste powder. In parts by weight, 37 parts of silver nitrate and 3 parts of silver acetate were dissolved in water, and 59 parts of plant waste powder (wheat straw powder) and 1 part of γ-methacryloyloxypropyltrimethoxysilane were added in sequence , stirred evenly, and absorbed in the dark for 200 min, and then placed in an oven at 120 °C for 10 h to obtain a silver-loaded antibacterial agent based on plant waste powder.

After testing, the nano-silver is uniformly dispersed on the plant waste powder, and the average particle size of the nano-silver is about 18.3nm. The antibacterial rates of the obtained antibacterial agent against Escherichia coli and Staphylococcus aureus are both 100% (the antibacterial performance test standard is GB/T21510-2008).

Example 4

The plant waste (poplar) is pulverized and ground into powder to obtain 600 mesh plant waste powder. In parts by weight, 38 parts of silver nitrate were dissolved in water, 50 parts of plant waste powder (poplar wood powder) and 12 parts of vinyltriethoxysilane were added in turn, stirred evenly, protected from light and adsorbed for 60 minutes, and then placed in After drying in an oven at 100° C. for 18 hours, a silver-loaded antibacterial agent based on plant waste powder was obtained.

After testing, the nano-silver is uniformly dispersed on the plant waste powder, and the average particle size of the nano-silver is about 17.6nm. The antibacterial rates of the obtained antibacterial agent against Escherichia coli and Staphylococcus aureus are both 100% (the antibacterial performance test standard is GB/T21510-2008).

Comparative Example 1

The plant waste (bamboo and wood) is pulverized and ground into powder to obtain 200 mesh plant waste powder. In parts by weight, dissolve 30 parts of silver nitrate in water, add 70 parts of plant waste powder (bamboo wood powder), stir evenly, avoid light and absorb for 100 minutes, and then place it in an oven at 90 ° C to dry for 24 hours to obtain a plant waste-based The SEM image of the silver-loaded antibacterial agent of the powder is shown in Figure 1(a). Compared with Example 1, this comparative example has the same raw material ratio and preparation method, and the difference is only that: this comparative example does not add a silane coupling agent. The results show that the nano-silver is not uniformly dispersed on the plant waste powder, and the interfacial force between the nano-silver and the substrate is weak, so the antibacterial effect of the obtained antibacterial agent will be deteriorated. After testing, the antibacterial rates of the obtained antibacterial agent against Escherichia coli and Staphylococcus aureus are 86% and 88% respectively (the antibacterial performance test standard is GB/T21510-2008).

Comparative Example 2

Compared with Example 2, the preparation method of this comparative example is basically the same, and the difference is only: the weight parts of silver acetate and plant waste powder (coconut shell powder) added in this comparative example are: 1 part, 94 parts share.

The results show that the nano-silver is evenly dispersed on the plant waste powder, but the antibacterial rate of the obtained antibacterial agent against Escherichia coli and Staphylococcus aureus is only 68% and 61% (the antibacterial performance test standard is GB/T 21510-2008).

Comparative Example 3

Compared with Example 4, the preparation method of this comparative example is basically the same, and the difference is only that: the weight parts of silver nitrate and plant waste powder (poplar powder) added in this comparative example are: 44 parts, 44 parts by weight, respectively. share.

The results showed that the average particle size of the nano-silver grown on the plant waste powder was about 46.2 nm. The antibacterial rates of the obtained antibacterial agent against Escherichia coli and Staphylococcus aureus are only 83% and 78% (the antibacterial performance test standard is GB/T21510-2008).

Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above-mentioned specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essential content of the present invention. The embodiments of the present application and features in the embodiments may be arbitrarily combined with each other without conflict.

Claims (10)

1. A preparation method of a silver-loaded antibacterial agent based on plant waste powder is characterized by comprising the following steps:

crushing plant wastes, and grinding the plant wastes into powder to obtain plant waste powder;

dissolving 5-40 parts of silver salt in water, sequentially adding 50-90 parts of plant waste powder and 1-12 parts of silane coupling agent, uniformly stirring, adsorbing in a dark place, and drying to obtain the silver-loaded antibacterial agent based on the plant waste powder.

2. The method of preparing a silver-loaded antimicrobial agent based on plant waste powder of claim 1, wherein: the plant waste comprises one or a mixture of several of crop straws, waste wood and plant shells.

3. The method of preparing a silver-loaded antimicrobial agent based on plant waste powder of claim 1, wherein: the silver salt comprises one of silver nitrate and silver acetate or a mixture of the silver nitrate and the silver acetate.

4. The method of preparing a silver-loaded antimicrobial agent based on plant waste powder of claim 1, wherein: one end of the molecular structure of the silane coupling agent can act with groups in plant wastes, and the other end of the molecular structure of the silane coupling agent can act with nanoparticles.

5. The method of preparing a silver-loaded antimicrobial agent based on plant waste powder according to claim 1 or 4, wherein: the silane coupling agent comprises one or a mixture of more of gamma-aminopropyltriethoxysilane, gamma-glycidoxypropyltrimethoxysilane, gamma-methacryloxypropyltrimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, vinyltris (beta-methoxyethoxy) silane, gamma-mercaptopropyltriethoxysilane, gamma-mercaptopropyltrimethoxysilane, N- (beta-aminoethyl) -gamma-aminopropyltrimethoxysilane (ethyl) oxysilane and N-beta- (aminoethyl) -gamma-aminopropylmethyldimethoxysilane.

6. The method of preparing a silver-loaded antimicrobial agent based on plant waste powder of claim 1, wherein: the adsorption time is 10-200 min.

7. The method of preparing a silver-loaded antimicrobial agent based on plant waste powder of claim 1, wherein: the drying time is 10-36h, and the temperature is 60-120 ℃.

8. The method of preparing a silver-loaded antimicrobial agent based on plant waste powder of claim 1, wherein: the particle size range of the plant waste powder is 40-600 meshes.

9. The silver-loaded antibacterial agent based on plant waste powder is characterized by comprising the following components in parts by weight:

5-40 parts of silver salt; 50-90 parts of plant waste powder; 1-12 parts of a silane coupling agent.

10. The silver-loaded antimicrobial agent based on plant waste powder of claim 9, wherein the plant waste comprises one or a mixture of crop straw, wood waste, plant husks;

the silver salt comprises one or a mixture of silver nitrate and silver acetate;

one end of the molecular structure of the silane coupling agent can act with groups in plant wastes, and the other end of the molecular structure of the silane coupling agent can act with nano-particles;

the silane coupling agent comprises one or a mixture of more of gamma-aminopropyltriethoxysilane, gamma-glycidoxypropyltrimethoxysilane, gamma-methacryloxypropyltrimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, vinyltris (beta-methoxyethoxy) silane, gamma-mercaptopropyltriethoxysilane, gamma-mercaptopropyltrimethoxysilane, N- (beta-aminoethyl) -gamma-aminopropyltrimethoxysilane (ethyl) oxysilane and N-beta- (aminoethyl) -gamma-aminopropylmethyldimethoxysilane.

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