A sustained-release natural nanotube-based bactericidal and disinfectant composite material and preparation method thereof

Abstract

A slow-release natural nanotube-based bactericidal and disinfectant composite material and its preparation method. In this method, halloysite nanotube powder and trichloroisocyanuric acid powder are dissolved in an organic solvent to obtain a mixed system; graphene oxide powder, a dispersant, an activator and a binder are uniformly dispersed, and then the dispersant is heated and dissolved to obtain a mixed solution; the mixed solution and the mixed system are mixed into a dough-like shape, and then granulated by extrusion and dried in sequence to obtain the slow-release natural nanotube-based bactericidal and disinfectant composite material. In the present invention, trichloroisocyanuric acid is the active ingredient, the release rate of ClO2 can be adjusted, the preparation process is simple, environmentally friendly and economical during use, and it can achieve the disinfection of germs and viruses without secondary pollution in crowded public environments, and has great application value.

Description

Technical Field

[0001] The present invention belongs to the field of sterilization and disinfection, and particularly relates to a slow-release natural nanotube-based sterilization and disinfection composite material and a preparation method thereof. Background Art

[0002] Trichloroisocyanuric acid, commonly known as strong chlorine essence, belongs to the class of chloroisocyanuric acid compounds. It is a highly efficient, broad-spectrum and low-toxic disinfectant and has been officially approved by the US Federal Food and Drug Administration (FDA) and the Environmental Protection Agency (BPA) for use in the disinfection of food and drinking water. It is also the first-choice drug recommended by the United Nations Disease Control Center for the prevention of hepatitis B virus.

[0003] Trichloroisocyanuric acid can be made into tablets, aqueous solutions, powders and other dosage forms and is widely used in industries such as food, medical and health, agriculture, fishery, textile, and papermaking. It is a fine chemical product with high added value. However, during the use of trichloroisocyanuric acid, an activator is required to promote the release of ClO2 with strong disinfection performance. The release rate is fast and difficult to control, and there is a problem of secondary pollution to the people in the use area; the storage time of the prepared disinfection product is short and it is difficult to maintain a long-term disinfection effect; these disadvantages seriously limit the application of trichloroisocyanuric acid in the disinfection of germs and viruses in the public environment with a dense population. Summary of the Invention

[0004] In view of the defects existing in the existing germ and virus disinfection technologies in the public environment air, the present invention provides a slow-release natural nanotube-based sterilization and disinfection composite material and a preparation method thereof, with trichloroisocyanuric acid as the active ingredient, the ClO2 release rate can be adjusted, the preparation process is simple, environmentally friendly and economical during use, and it can achieve non-secondary pollution disinfection of germs and viruses in the public environment with a dense population, and has great application value.

[0005] The present invention is realized through the following technical solutions:

[0006] A slow-release natural nanotube-based sterilization and disinfection composite material, wherein the natural nanotube is halloysite nanotube, trichloroisocyanuric acid is adsorbed on the inner wall of the halloysite nanotube, an activator and graphene oxide are adsorbed on the outer wall of the halloysite nanotube, the graphene oxide adsorbs the activator, and the activator and trichloroisocyanuric acid are relatively distributed.

[0007] Preferably, the diameter of the halloysite nanotube is 10 - 100 nm, and the activator is citric acid or oxalic acid.

[0008] A preparation method of a slow-release natural nanotube-based sterilization and disinfection composite material, comprising the following steps:

[0009] S1. Dissolve halloysite nanotube powder and trichloroisocyanuric acid powder in an organic solvent according to a mass ratio of (50 - 89.8):(0.5 - 20) to obtain a mixed system a;

[0010] S2. Uniformly disperse graphene oxide powder, dispersant, activator and binder. The masses of the graphene oxide powder and the binder respectively account for 0.1% - 1% and 10% - 40% of the mixed system a to obtain a mixed system b, and then heat to dissolve the dispersant to obtain a mixed solution;

[0011] S3. Mix the mixed solution with the mixed system a into a dough-like shape, and then extrude and granulate and dry in sequence to obtain a slow-release natural nanotube-based sterilization and disinfection composite material.

[0012] Preferably, the organic solvent described in S1 is benzene, toluene, acetone or ethanol, and the mass ratio of the organic solvent to the trichloroisocyanuric acid powder is (10 - 30):(0.5 - 20).

[0013] Preferably, the binder described in S2 is a neutral silica sol with a mass percentage concentration of SiO2 of 30% - 50%. Add the graphene oxide powder, dispersant and activator to the neutral silica sol and disperse them uniformly to obtain a mixed system b.

[0014] Preferably, the dispersant described in S2 is polyvinylpyrrolidone powder.

[0015] Furthermore, the mass of the polyvinylpyrrolidone powder accounts for 0.5% - 5% of the mixed system a.

[0016] Preferably, the activator described in S2 accounts for 0.5% - 10% of the mass of the mixed system a.

[0017] Preferably, in S2, heat the mixed system b to 60 - 85 °C and keep it warm for 1.5 - 2.5 h, and then cool it naturally to obtain a mixed solution.

[0018] Preferably, in S3, after extrusion and granulation, spheres with a particle size of 2 - 4 mm are obtained, and then dried at 80 - 100 °C for 6 - 12 h to obtain a slow-release natural nanotube-based sterilization and disinfection composite material.

[0019] Compared with the prior art, the present invention has the following beneficial technical effects:

[0020] The present invention relates to a slow-release natural nanotube-based bactericidal and disinfectant composite material. Halloysite nanotubes are in full contact with trichloroisocyanuric acid. The halloysite nanotubes with a hollow structure provide abundant pores, enabling trichloroisocyanuric acid to be adsorbed and loaded inside the halloysite nanotubes. Graphene oxide and an activator are uniformly distributed on the outer wall of the halloysite nanotubes with a hollow structure. The activator and trichloroisocyanuric acid are relatively distributed, thereby effectively controlling the contact area between the activator and trichloroisocyanuric acid. In this way, the reaction rate between trichloroisocyanuric acid and the activator is controlled, and the release rate of ClO2 is regulated, ensuring both the disinfection effect and the long-term stability of the disinfection product made from trichloroisocyanuric acid. Graphene oxide has a large specific surface area and a polyhydroxy structure. Its lamellar structure can adsorb the activator and can firmly adsorb microbial cells in fine air particles, further promoting the bactericidal effect by virtue of its physical structure. Since graphene oxide has a single-layer structure and strong mechanical strength, it can destroy the cell structure of the cells, leading to the death of the cells and thus producing a synergistic effect.

[0021] The present invention relates to a preparation method of a slow-release natural nanotube-based bactericidal and disinfectant composite material. Halloysite nanotubes are used as a carrier, and its hollow nanotubular structure can provide a large number of adsorption sites, greatly improving the loading amount of the effective bactericidal components in the composite material. Organic solvents can achieve the uniform loading of trichloroisocyanuric acid inside the halloysite nanotubes, and binders can be used to compound graphene oxide, dispersants, and activators. In addition, halloysite nanotubes can also provide a physical shielding effect, reducing the inactivation of chlorine-containing components. The present invention uses graphene oxide. The special two-dimensional planar structure and π-π conjugation system of graphene oxide endow it with excellent adsorption ability. The oxygen-containing functional groups in graphene oxide form hydrogen bonds with the activator, forming a cross-linked structure to reduce the volatilization of the active ingredients. In addition, graphene oxide further promotes the bactericidal effect through its own physical action. The preparation method used in the present invention is easy to operate, and the raw materials are cheap and easily available, suitable for large-scale industrial production. Compounding graphene oxide with solid trichloroisocyanuric acid to prepare a more efficient solid chlorine bactericidal material has greater value and application and promotion prospects. Brief Description of the Drawings

[0022] Figure 1 It is the X-ray diffraction (XRD) pattern of the bactericidal and disinfectant material prepared in Example 2 of the present invention.

[0023] Figure 2 It is the pore size distribution diagram of the bactericidal and disinfectant material prepared in Example 2 of the present invention.

[0024] Figure 3 It is the low-magnification transmission electron microscope (TEM) image of the bactericidal and disinfectant material prepared in Example 2 of the present invention.

[0025] Figure 4This is the high-magnification transmission electron microscope (TEM) image of the bactericidal and disinfectant material prepared in Example 2 of the present invention. Detailed implementation manners

[0026] The technical solutions of the present invention will be further described in detail through specific embodiments below, but the protection scope of the present invention is not limited to the following embodiments.

[0027] Graphene oxide is a new type of green and environment-friendly material. When it comes into direct contact with bacteria, the sharp edges of its sheets directly damage the cell membrane structure through mechanical damage or destroy the cell membrane by directly extracting phospholipid molecules on the cell membrane on a large scale, causing the destruction of the bacterial structure and the disorder of its functions. At the same time, the rich charged groups on the surface of graphene oxide can interact with microorganisms and then enter the microorganisms, making the free radical metabolism balance of the microorganisms out of balance, resulting in peroxidative damage to the biofilm and macromolecular substances, thereby achieving the antibacterial effect.

[0028] The present invention provides a slow-release natural nanotube-based bactericidal and disinfectant composite material. Halloysite nanotubes are in full contact with trichloroisocyanuric acid. The length and diameter of the halloysite nanotubes are about 100 - 500 nm and 10 - 100 nm respectively. The halloysite nanotubes with a hollow structure provide rich pores, enabling trichloroisocyanuric acid to be adsorbed and loaded inside the halloysite nanotubes. Graphene oxide and an activator are uniformly distributed on the outer wall of the halloysite nanotubes with a hollow structure. The activator and trichloroisocyanuric acid are distributed relatively, thus effectively controlling the contact area between the activator and trichloroisocyanuric acid, controlling the reaction rate between trichloroisocyanuric acid and the activator, and realizing the regulation of the release rate of ClO2. This not only ensures the disinfection effect but also ensures the long-term stability of the disinfection product made of trichloroisocyanuric acid. Graphene oxide has a large specific surface area and a polyhydroxy structure. Its sheet structure can adsorb the activator, and at the same time can firmly adsorb the microbial cells in the fine air particles, further promoting the bactericidal effect by virtue of its own physical structure. Since graphene oxide is a single-layer structure and has strong mechanical strength, it can destroy the cell structure of the bacteria, thereby causing the death of the bacteria and then producing a synergistic effect.

[0029] The present invention also provides a method for preparing a slow-release natural nanotube-based bactericidal and disinfectant composite material. Halloysite nanotube powder and trichloroisocyanuric acid solid powder are mixed in an organic solvent to obtain a mixed system. The organic solvent is benzene, toluene, acetone or ethanol, so as to achieve uniform loading of trichloroisocyanuric acid in halloysite nanotubes. Then, a binder is used to compound graphene oxide, a dispersant and an activator. The binder is a neutral silica sol with a SiO2 mass percentage concentration of 30% to 50%, the dispersant is polyvinylpyrrolidone, and the activator is citric acid or oxalic acid to obtain a mixed solution. The mixed system and the mixed solution are mixed into a dough-like shape, and then the uniform mixing of the mixed system and graphene oxide is realized. It is put into a granulator for extrusion granulation and then dried to prepare the above-mentioned slow-release natural nanotube composite solid chlorine bactericidal and disinfectant material. Halloysite nanotubes and graphene oxide not only serve as high-capacity carriers for effective disinfection components and activating components, but also can provide effective physical shielding, which can solve the problems of low loading amount of traditional disinfectants and difficult control of release period.

[0030] Specifically, the method for preparing the slow-release natural nanotube-based bactericidal and disinfectant composite material includes the following steps:

[0031] (1) Weigh halloysite nanotube powder, mix it evenly with trichloroisocyanuric acid powder and an organic solvent (benzene, toluene, acetone or ethanol) to obtain a mixed system a, wherein the trichloroisocyanuric acid powder accounts for 0.5% to 20% of the mass of the mixed system a, the organic solvent accounts for 10% to 30% of the mass of the mixed system a, and thus the halloysite nanotube powder accounts for 50% to 89.8% of the mass of the combined system a.

[0032] (2) Measure the binder (neutral silica sol with a SiO2 mass percentage concentration of 30% to 50%) and place it in a beaker, then add graphene oxide powder, a dispersant (polyvinylpyrrolidone powder) and an activator (citric acid or oxalic acid) and stir evenly to obtain a mixed system b. The binder accounts for 10% to 40% of the mass of the mixed system a, the graphene oxide powder accounts for 0.1% to 1% of the mass of the mixed system a, the dispersant accounts for 0.5% to 5% of the mass of the mixed system a, and the activator accounts for 0.5% to 10% of the mass of the mixed system a. Heat the mixed system b in a water bath to 60 to 85 °C and keep it at a constant temperature for 1.5 to 2.5 h to fully dissolve the dispersant, then remove the water bath and wait for the obtained mixed solution to cool.

[0033] (3) Mix the mixed solution with the mixed system a into a dough-like substance, then put it into a granulator for extrusion granulation to make solid small balls with a particle size of 2 to 4 mm, and dry them at 80 to 100 °C for 6 to 12 h to remove the organic solvent, thus obtaining the product.

[0034] The slow-release natural nanotube composite solid chlorine disinfection material obtained in the present invention is applied to the disinfection and killing of various pathogenic microorganisms, namely Escherichia coli, Aspergillus niger, Staphylococcus aureus, and porcine gastroenteritis coronavirus.

[0035] Example 1

[0036] Weigh 300 g of halloysite nanotube powder, 60 g of trichloroisocyanuric acid powder, and 100 ml of toluene and mix them evenly.

[0037] Immediately weigh 6 g of graphene oxide powder, 30 g of polyvinylpyrrolidone powder, and 30 g of citric acid, disperse them simultaneously in 160 mL of neutral silica sol with a SiO2 mass percentage concentration of 30%, stir evenly, place them in a water bath and heat to 80 °C. After 2 h, remove the water bath and wait for it to cool.

[0038] Mix the mixed solution with the mixed system to form a dough-like substance, then put it into a granulator to make solid balls with a particle size of 2 - 4 mm, and dry them in a forced-air drying oven at 80 °C for 10 h to obtain the product.

[0039] Example 2

[0040] Weigh 300 g of halloysite nanotube powder, 45 g of trichloroisocyanuric acid powder, and 100 ml of acetone and mix them evenly.

[0041] Immediately weigh 20 g of graphene oxide powder, 40 g of polyvinylpyrrolidone powder, and 25 g of citric acid, disperse them simultaneously in 160 mL of neutral silica sol with a SiO2 mass percentage concentration of 40%, stir evenly, place them in a water bath and heat to 80 °C. After 2 h, remove the water bath and wait for it to cool.

[0042] Mix the mixed solution with the mixed system to form a dough-like substance, then put it into a granulator to make solid balls with a particle size of 2 - 4 mm, and dry them in a forced-air drying oven at 90 °C for 8 h to obtain the product.

[0043] Example 3

[0044] Weigh 300 g of halloysite nanotube powder, 50 g of trichloroisocyanuric acid powder, and 100 ml of ethanol and mix them evenly.

[0045] Immediately weigh 5.0 g of graphene oxide powder, 25 g of polyvinylpyrrolidone powder, and 45 g of citric acid, disperse them simultaneously in 160 mL of neutral silica sol with a SiO2 mass percentage concentration of 50%, stir evenly, place them in a water bath and heat to 80 °C. After 2 h, remove the water bath and wait for it to cool.

[0046] Mix the mixed solution with the mixed system to form a dough-like substance, then put it into a granulator to make solid balls with a particle size of 2 - 4 mm, and dry them in a forced-air drying oven at 95 °C for 8 h to obtain the product.

[0047] Example 4

[0048] Weigh 300 g of halloysite nanotube powder, 45 g of trichloroisocyanuric acid powder and 100 ml of benzene and mix them evenly.

[0049] Subsequently, weigh 35 g of graphene oxide powder, 30 g of polyvinylpyrrolidone powder and 25 g of citric acid and disperse them simultaneously in 160 mL of neutral silica sol with a mass percentage concentration of 30% SiO2 and stir evenly. Place it in a water bath and heat it to 80 °C. After 2 h, remove the water bath and wait for it to cool.

[0050] Mix the mixed solution with the mixed system into a dough-like substance, and then put it into a granulator to make solid balls with a particle size of 2 - 4 mm, and dry them in a forced-air drying oven at 100 °C for 8 h to obtain the product.

[0051] As Figure 1 shown by the X-ray diffraction (XRD) pattern of [], the obtained bactericidal and disinfectant material in Example 2 was subjected to XRD testing. The main diffraction peaks in the figure are consistent with Al2Si2O5(OH)4 (PDF#29 - 1487) in the PDF card, which is consistent with the composition of halloysite nanotubes. Therefore, the complete crystal structure of halloysite nanotubes is retained in the natural nanotube-based bactericidal and disinfectant composite material, and the addition of graphene oxide, activator and trichloroisocyanuric acid does not change the crystal structure of halloysite nanotubes.

[0052] The specific surface area and porosity analysis test shows that the specific surface area of this bactericidal and disinfectant composite material is 50.4527 m 2 / g. In addition, as can be seen from Figure 2 it, the maximum pore volume of this bactericidal and disinfectant composite material is 0.156652 cm 3 / g, and the pore diameter is mainly distributed in the range of 2 - 100 nm, with an average value of 10.7501 nm. Therefore, the pore structure distribution of the bactericidal and disinfectant composite material is mainly mesopores (2 - 50 nm) and macropores (above 50 nm). Halloysite nanotubes have a good specific surface area and pore structure, which can provide suitable adsorption sites for trichloroisocyanuric acid and graphene. Trichloroisocyanuric acid absorbs moisture in the air, and at the same time the activator penetrates into the halloysite nanotubes, releasing ClO2 to react with the contacted bacteria or viruses. Since the content of ClO2 is very low, it cannot be directly characterized to intuitively reflect the regulation of the ClO2 release rate, which will be described later.

[0053] As Figure 3As shown in the low-magnification transmission electron microscope (TEM) image, the microstructure of the sterilizing composite material prepared in Example 2 is composed of nanotubes with a diameter of dozens of nanometers stacked together, and a large number of fine granular substances are loaded on the tube wall and inside the tube wall. It can be seen from the electron microscope image that the addition of trichloroisocyanuric acid does not affect the structure of the nanotubes. By Figure 4 As shown in the high-magnification transmission electron microscope (TEM) image, a large number of small particles have entered the lumen of halloysite nanotubes. Halloysite nanotubes provide a good loading space for trichloroisocyanuric acid, thereby effectively controlling the contact between trichloroisocyanuric acid and the activator and controlling the release rate of ClO2.

[0054] As can be seen from Table 1, for the granular sterilizing composite material prepared in Example 2, after disinfecting Escherichia coli, Aspergillus niger, Staphylococcus aureus, and porcine gastroenteritis coronavirus for 20 min by using the "Disinfection Technical Specification" (2002 Edition), Part 2 (2.1.1.9), the disinfection performance is strong. In three parallel experiments, 20 g of the above-mentioned sterilizing material and a sterilization effect of 20 min can both achieve a killing logarithm value greater than 5.

[0055] Table 1

[0056]

[0057] In addition, by processing this sterilizing composite material as the main material into a sterilizing purification module composed of a filter material and a filter frame, where the composite material is the filter material with a thickness of 3 cm, the filter frame is a PVC plastic perforated plate, and is encapsulated with a PVC large-hole screen. A third-party testing agency uses this module and conducts a microbial disinfection performance test in a 1 m 3 environmental chamber according to the "Test Method for Virus Removal Performance of Air Purifiers and Similar Functional Products" (T / SAEPI 005-2020), and finds that this module can maintain good microbial disinfection activity within 200 h; the specific microorganisms tested are: Escherichia coli, Staphylococcus aureus, and porcine gastroenteritis coronavirus. Taking Al2O3 spheres impregnated with a conventional chlorine-containing disinfectant with the same concentration as the comparison object for the ClO2 release rate, a sterilizing purification module is made of Al2O3 spheres impregnated with a conventional chlorine-containing disinfectant. The processing method is the same as above, the filter material quality is the same except for the filter material, and the filter frame and the corresponding filter mesh are of the same material and size. Its sterilization activity can only be maintained for 50 h. The above performance test results fully demonstrate that this material has good ClO2 slow-release performance.

Claims

1. A preparation method of a sustained-release natural nanotube-based bactericidal and disinfectant composite material, characterized in that, It includes the following steps: S1. Dissolve halloysite nanotube powder and trichloroisocyanuric acid powder in an organic solvent according to a mass ratio of (50 - 89.8): (0.5 - 20). The diameter of the halloysite nanotubes is 10 - 100 nm to obtain a mixed system a; S2. Uniformly disperse graphene oxide powder, dispersant, activator and binder. The activator is citric acid or oxalic acid, the binder is neutral silica sol with a SiO2 mass percentage concentration of 30% - 50%, the dispersant is polyvinylpyrrolidone powder. The masses of the graphene oxide powder and the binder respectively account for 0.1% - 1% and 10% - 40% of the mixed system a to obtain a mixed system b, and then heat to dissolve the dispersant to obtain a mixed solution; S3. Mix the mixed solution with the mixed system a into a dough-like shape, and then sequentially extrude and granulate and dry to obtain a slow-release natural nanotube-based sterilizing and disinfecting composite material. Trichloroisocyanuric acid is adsorbed on the inner wall of the halloysite nanotubes, the outer wall of the halloysite nanotubes adsorbs the activator and graphene oxide, graphene oxide adsorbs the activator, and the activator and trichloroisocyanuric acid are relatively distributed.

2. The preparation method of the sustained-release natural nanotube-based bactericidal and disinfectant composite material according to claim 1, characterized in that The organic solvent described in S1 is benzene, toluene, acetone or ethanol, and the mass ratio of the organic solvent to the trichloroisocyanuric acid powder is (10 - 30):(0.5 - 20).

3. The preparation method of the sustained-release natural nanotube-based bactericidal and disinfectant composite material according to claim 1, characterized in that, In S2, the graphene oxide powder, dispersant and activator are added to the neutral silica sol and uniformly dispersed to obtain a mixed system b.

4. The preparation method of the sustained-release natural nanotube-based bactericidal and disinfectant composite material according to claim 1, characterized in that, The mass of the polyvinylpyrrolidone powder accounts for 0.5% - 5% of the mixed system a.

5. The preparation method of the sustained-release natural nanotube-based bactericidal and disinfectant composite material according to claim 1, characterized in that, The activator described in S2 accounts for 0.5% - 10% of the mass of the mixed system a.

6. The preparation method of the sustained-release natural nanotube-based bactericidal and disinfectant composite material according to claim 1, characterized in that, In S2, the mixed system b is heated to 60 - 85 °C and kept warm for 1.5 - 2.5 h, and then naturally cooled to obtain a mixed solution.

7. The preparation method of the sustained-release natural nanotube-based bactericidal and disinfectant composite material according to claim 1, characterized in that, In S3, after extrusion and granulation, spheres with a particle size of 2 - 4 mm are obtained, and then dried at 80 - 100 °C for 6 - 12 h to obtain a slow-release natural nanotube-based sterilizing and disinfecting composite material.

Images