Preparation and application of low-silver-loading efficient antiviral activated carbon

Abstract

The invention discloses a preparation method and application of low-silver-loading efficient antiviral activated carbon with bamboo-based carbon as matrix carbon. The nano-silver (AgNPs) and the activated carbon are materials widely applied to water treatment, the AgNPs are good in virus inactivation effect, and the activated carbon is high in adsorption capacity, so that the problems that the AgNPs are prone to agglomeration in water and the virus inactivation efficiency of the activated carbon is low can be solved by loading the AgNPs on the activated carbon, and then the virus inactivation efficiency is improved. The preparation method comprises the following steps: firstly, preparing activated carbon by taking a bamboo by-product as a raw material, then uniformly mixing the activated carbon with a small amount of Ag < + >-containing solution, and calcining at high temperature to prepare nano-silver-loaded activated carbon (AC-AgNPs) with low silver loading capacity, which is applied to the field of water antivirus, especially the field of drinking water. The method has the characteristics of good inactivation effect, low cost, environmental friendliness and the like, and has important significance for promoting the development of a water environment virus safety technology.

Description

Technical Field

[0001] The present invention relates to activated carbon preparation and modification technology and its antiviral application field, and in particular to a preparation method of a low-cost composite activated carbon material for drinking water antiviral and its application. Background Art

[0002] Viruses pose one of the greatest threats to human health. Virus-related safety incidents in drinking water have occurred frequently both domestically and internationally, posing a threat to human health. Common methods for inactivating viruses in drinking water treatment include boiling, free chlorine, chlorine dioxide, ultraviolet light, and ozone. However, numerous waterborne infectious disease outbreaks worldwide indicate that viruses, due to their simple and stable structures, cannot achieve 100% inactivation with these common methods. Therefore, the need to supplement, develop, and optimize technologies for inactivating viruses in drinking water is urgent. A multi-stage barrier strategy will be essential for addressing the safety of enteric viruses in drinking water.

[0003] Silver nanoparticles are nanomaterials with excellent anti-pathogenic properties. Numerous studies have used them to inactivate bacteria, viruses, and protozoa in drinking water, with good results. However, their high surface energy can lead to aggregation in water, impairing their antimicrobial effectiveness. Activated carbon, produced from carbon-containing organic materials through specialized processes such as pyrolysis and activation, possesses a well-developed pore structure, a large specific surface area, and abundant surface chemical functional groups, making it a carbon material with specific adsorption capabilities. While some studies have used activated carbon to adsorb viruses, the adsorption efficiency is low. Loading silver nanoparticles onto activated carbon not only traps viruses but also further inactivates them, providing a post-disinfection, multi-level barrier. Furthermore, the production cost of silver nanoparticles is high, and Ag poses certain health risks to humans. Therefore, the ideal approach is to prepare activated carbon-silver nanoparticle composites with low silver loadings and high inactivation efficiency.

[0004] Therefore, the present invention proposes a method for preparing low-silver-loading, high-efficiency antiviral activated carbon, which achieves a higher virus inactivation rate with a lower silver loading, and puts it into practical application, which has positive significance for promoting the development of water environment virus safety technology and multi-level barrier strategy. Summary of the Invention

[0005] In response to the current virus safety issues in drinking water, the first purpose of this invention is to propose a method for preparing a low-silver-loaded, highly effective antiviral activated carbon, AC-AgNPs, which ensures high inactivation efficiency at a low silver loading, reduces costs, and conserves resources. The second object of the present invention is to provide a low silver loading, highly effective antiviral composite material AC-AgNPs; The third object of the present invention is to provide an application of AC-AgNPs.

[0006] In order to achieve the above purpose, the first technical solution adopted by the present invention is to use bamboo by-products (waste) as raw materials to make activated carbon as the matrix carbon, and to mix it with a small amount of Ag-containing + The solutions are mixed uniformly and calcined at high temperature to obtain AC-AgNPs, comprising the following steps: (1) Containing Ag + The solution is made by mixing a silver salt solution and an alkaline compound; (2) The small amount of Ag in step (1) + The solution and bamboo-based activated carbon powder are stirred and mixed evenly; (3) calcining the mixture of step (2) at a high temperature of 110-250°C for 2-3 hours; (4) Drying the AC-AgNPs prepared in step (3) in a vacuum drying oven at 80-110°C for 12-24 hours to remove moisture; In the step (1), the silver salt solution can be AgNO3, AgF, AgClO3, AgClO4 or other water-soluble silver salts, and the alkaline compound can be sodium thiosulfate, ammonia water, sodium sulfite or other compounds; In step (2), the mixture must be stirred and mixed thoroughly. The ratio of the silver salt solution to the alkaline compound can be 0.160 g:0 μL to 0.160 g:10 μL. In the step (3), calcination is carried out under an inert gas atmosphere.

[0007] A second object of the present invention is to provide AC-AgNPs with low silver loading and high antiviral properties, which are prepared by the above-mentioned preparation method. Preferably, the silver salt is a soluble silver salt, the alkaline compound is ammonia water, the ratio is 0.160g:0μL~0.160g:10μL, the ratio of silver salt to bamboo-based charcoal is 0.160 / 10-0.480 / 10 (w / w), and the silver loading of AC-AgNPs is 0.1wt.%-0.3 wt.%.

[0008] The third object of the present invention is to provide an application of the AC-AgNPs as described above, wherein the technical solution comprises the following steps: (1) Using MS2 phage as a virus indicator, the logarithmic removal value (LRV) was used to represent the inactivation ability of AC-AgNPs against MS2 phage; (2) AC-AgNPs were placed into prepared MS2 phage suspensions with different initial titers for inactivation; (3) AC-AgNPs were placed in MS2 phage suspension at different temperatures for inactivation; (4) Add the MS2 phage mother solution to tap water and add AC-AgNPs for inactivation; In the step (1), the double-layer agar plate method is used to observe the plaques; In the steps (2) and (3), a buffer solution is used to prepare the MS2 phage suspension. Preferably, the present invention uses a PBS buffer solution; In step (3), the external environment temperature is changed to control the water temperature.

[0009] The present invention has the following beneficial effects compared to the prior art: The present invention uses bamboo byproducts (waste) as raw materials to prepare bamboo-based activated carbon, turning waste into treasure and saving resources. A lower concentration of silver salt is used to prepare AC-AgNPs, which reduces costs, is environmentally friendly, and has a simple preparation method that is easy to operate, fully embodying the principle of sustainable development. The AC-AgNPs prepared by the present invention have low silver loading and high inactivation efficiency, and are easy to combine with traditional drinking water treatment processes to achieve a multi-level barrier strategy for drinking water virus safety. The application of AC-AgNPs in the present invention fully considers the practical factors of drinking water treatment, thereby achieving the purpose of solving practical problems and enhancing its applicability; The present invention uses MS2 bacteriophage, one of the bacteriophages with the strongest resistance to various disinfection methods, as a virus indicator. The invention is convenient to operate, non-toxic to the human body and representative. DETAILED DESCRIPTION

[0010] The present invention will be further described below by way of specific examples. The examples of the present invention are provided to enable those skilled in the art to better understand the present invention, and are not intended to limit the present invention in any way.

[0011] The preparation method and application of the present invention are carried out using the following examples but are not limited to the following examples. Unless otherwise specified, the dosage of AC-AgNPs in the following examples is 500 mg / L and the mixture is shaken at 120 rpm in a constant temperature shaker for 2 h.

[0012] Example 1: First, 0.160 g of AgNO3 was mixed with 10 μL of ammonia water and then dropped into 10.0 g of bamboo-based charcoal. The mixture was thoroughly stirred and evenly mixed. The mixture was placed in a tube furnace and calcined at 200 ° C for 2 h. The mixture was taken out and dried in a vacuum drying oven at 110 ° C for 24 h to obtain 0.1 wt.% AC-AgNPs. At 35 ° C, 0.1 wt.% AC-AgNPs were added to 40 mL of an initial titer of 10 7 PFU / mLMS2 phage suspension was prepared. After the reaction, the phage plaques were observed by the double-layer agar plate method, and the LRV was calculated to be 3.08, indicating that the removal rate reached 99.9%.

[0013] Example 2: First, 0.320 g of AgF was mixed with 20 μL of sodium thiosulfate and then added dropwise to 10.0 g of bamboo-based charcoal. The mixture was thoroughly stirred and evenly mixed. The mixture was placed in a tube furnace and calcined at 250°C for 2 h. The mixture was then taken out and dried in a vacuum drying oven at 110°C for 24 h to obtain 0.2 wt.% AC-AgNPs. At 25°C, 0.2 wt.% AC-AgNPs were added to 40 mL of 10% charcoal with an initial titer of 10. 6 PFU / mLMS2 phage suspension was prepared. After the reaction, the phage plaques were observed by double-layer agar plate method, and the LRV was calculated to be 2.89, indicating that the removal rate reached 99.0%.

[0014] Example 3: First, 0.320 g of AgClO3 was mixed with 20 μL of ammonia water and then added dropwise to 10.0 g of bamboo-based charcoal. The mixture was thoroughly stirred and evenly mixed. The mixture was placed in a tube furnace and calcined at 110°C for 2 h. The mixture was then taken out and dried in a vacuum drying oven at 110°C for 24 h to obtain 0.2 wt.% AC-AgNPs. At 35°C, 0.2 wt.% AC-AgNPs were added to 40 mL of a 10% initial titer. 5 PFU / mLMS2 phage suspension was prepared. After the reaction, the phage plaques were observed by double-layer agar plate method, and the LRV was calculated to be 4.00, indicating that the removal rate reached 99.99%.

[0015] Example 4: First, 0.480 g of AgNO3 was mixed with 30 μL of ammonia water and then dropped into 10.0 g of bamboo-based charcoal. The mixture was thoroughly stirred and evenly mixed. The mixture was placed in a tube furnace and calcined at 110°C for 2 h. The mixture was then taken out and dried in a vacuum drying oven at 110°C for 24 h to obtain 0.3 wt.% AC-AgNPs. At 35°C, 0.3 wt.% AC-AgNPs were added to 40 mL of a 10% aqueous solution. 4 PFU / mL MS2 phage suspension was prepared. After the reaction, the phage plaques were observed by double-layer agar plate method, and the LRV was calculated to be 4.32, with a removal rate of 100%.

[0016] Example 5: First, 0.480 g of AgClO4 was mixed with 30 μL of sodium sulfite and then added dropwise to 10.0 g of bamboo-based charcoal. The mixture was thoroughly stirred and evenly mixed. The mixture was placed in a tube furnace and calcined at 110°C for 2 h. The mixture was then taken out and dried in a vacuum drying oven at 110°C for 24 h to obtain 0.3 wt.% AC-AgNPs. At 15°C, 0.3 wt.% AC-AgNPs were added to 40 mL of an initial titer of 10 6 PFU / mL MS2 phage suspension was prepared. After the reaction, the phage plaques were observed by double-layer agar plate method, and the LRV was calculated to be 2.50, with a removal rate of 99.0%.

[0017] Example 6: First, 0.320 g of AgNO3 was added dropwise to 10.0 g of bamboo-based charcoal, stirred thoroughly, and calcined in a tube furnace at 250 ° C for 2 h. After that, it was taken out and dried in a vacuum drying oven at 110 ° C for 24 h to obtain 0.2 wt.% AC-AgNPs. At 35 ° C, 0.2 wt.% AC-AgNPs were added to 40 mL of an initial titer of 10 6 PFU / mL MS2 phage suspension, where the MS2 phage suspension was prepared from tap water and MS2 phage stock solution. After the reaction, the phage plaques were observed by double-layer agar plate method, and the calculated LRV was 3.76, that is, the removal rate reached 99.9%.

[0018] Example 7: First, 0.480 g of AgClO4 was added dropwise to 10.0 g of bamboo-based charcoal, stirred thoroughly, and calcined at 200 ° C for 2 h in a tube furnace. After that, the mixture was taken out and dried at 110 ° C for 24 h in a vacuum drying oven to obtain 0.3 wt.% AC-AgNPs. At 35 ° C, 0.3 wt.% AC-AgNPs were added to 40 mL of an initial titer of 10 6 PFU / mL MS2 phage suspension, after the reaction was completed, the phage plaques were observed by the double-layer agar plate method, and the LRV was calculated to be 4.03, that is, the removal rate reached 99.99%.

Claims

1. Low silver loading and high efficiency antiviral activated carbon - nano silver loaded activated carbon (AC-AgNPs) is characterized by Bamboo-based charcoal made from bamboo by-products is used as the matrix charcoal, and nanosilver is loaded onto the bamboo-based charcoal.

2. The AC-AgNPs according to claim 1, characterized in that The low silver loading is controlled by the ratio of silver salt and alkaline compound.

3. A method for preparing low silver-loaded, high-efficiency antiviral activated carbon with bamboo-based carbon as the matrix carbon according to any one of claims 1 and 2, characterized in that The following steps are involved: (1) Containing Ag + The solution is made by mixing a silver salt solution and an alkaline compound; (2) The small amount of Ag in step (1) + The solution and bamboo-based activated carbon powder are stirred and mixed evenly; (3) calcining the mixture of step (2) at a high temperature of 110-250°C for 2-3 hours; (4) Drying the AC-AgNPs prepared in step (3) in a vacuum drying oven at 80-110°C for 12-24 hours to remove moisture; In the step (1), the silver salt solution can be AgNO3, AgF, AgClO3, AgClO4 or other water-soluble silver salts, and the alkaline compound can be sodium thiosulfate, ammonia water, sodium sulfite or other compounds; In step (2), the mixture must be stirred and mixed thoroughly. The ratio of the silver salt solution to the alkaline compound can be 0.160 g:0 μL to 0.160 g:10 μL. In the step (3), calcination is carried out under an inert gas atmosphere.

4. Application of bamboo-based carbon as the matrix carbon with low silver loading and high efficiency antiviral activated carbon, characterized by The following steps are involved: MS2 phage was used as a virus indicator, and the logarithmic removal value (LRV) was used to express the inactivation ability of AC-AgNPs against MS2 phage; AC-AgNPs were placed into prepared MS2 phage suspensions with different initial titers for inactivation; AC-AgNPs were placed into MS2 phage suspension at different temperatures for inactivation; The MS2 phage stock solution was added dropwise to tap water and then AC-AgNPs were added for inactivation.