Kaolin long-acting antibacterial material and preparation method thereof

Abstract

The invention relates to the technical field of antibacterial materials, in particular to a kaolin long-acting antibacterial material and a preparation method thereof. The preparation method comprises the following steps: dispersing kaolin in deionized water, heating while stirring, slowly dropwise adding a precursor solution containing copper ions and zinc ions, and adjusting the pH value of the system to 10, so that the solution becomes light blue colloid from blue green; and then dropwise adding a reducing agent solution until the solution becomes brownish red, heating to 75-80 DEG C, continuously stirring for reaction, filtering, washing and drying. Zinc ions are added for lattice doping in the hydrothermal method reduction process, after Zn < 2 + > ions are successfully doped into Cu2O lattices, lattice distortion and defects can be introduced, and meanwhile conversion from Cuions to Cu < 2 + > and disproportionation reaction of Cu2O are effectively inhibited. And the stability of the chemical state and the microstructure of Cu2O can be kept in a long-term use or severe environment, so that the long-acting antibacterial effect is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of anti-disease bacteria materials, and particularly relates to a kaolin long-acting anti-disease bacteria material and a preparation method thereof. BACKGROUND

[0002] In recent years, due to the abuse of antibiotics, bacterial infections and multiple drug resistance have a major impact on public health, leading to high mortality and increased economic burden. Current research has found that metal materials such as silver, copper, zinc and titanium dioxide have the advantages of strong antibacterial activity and good biological safety and are widely used.

[0003] As a new type of antibacterial material in recent years, copper-based antibacterial materials have attracted more and more attention due to their low price and broad-spectrum antibacterial properties. Cuprous oxide is the most efficient among copper-based antibacterial materials, but due to its high activity, it is easy to be disproportionated or oxidized, leading to inactivation of active components and decay of antibacterial performance over time. Therefore, it is urgent to improve its stability.

[0004] Patent CN117800383A discloses a cuprous oxide stabilization method. The method uses a liquid phase reduction method to prepare cuprous oxide, which is calcined at high temperature under inert atmosphere protection or vacuum conditions. The cuprous oxide particles are diffused and recrystallized, so that the cuprous oxide has higher crystallinity and stability. However, the process is relatively complicated, and the energy consumption and cost are high. SUMMARY

[0005] The present application aims to provide a kaolin long-acting anti-disease bacteria material and a preparation method thereof to overcome the above-mentioned deficiencies of the prior art.

[0006] The first object of the present application is to provide a preparation method of a kaolin long-acting anti-disease bacteria material. The kaolin is dispersed in deionized water, heated under stirring, and a precursor solution containing copper ions and zinc ions is slowly added, and the pH of the system is adjusted to 10, so that the solution changes from blue-green to light blue colloid. Then, a reducing agent solution is added until the solution turns brown red, and the temperature is raised to 75-80℃, and the stirring reaction is continued. The product Kaol-Cu2O / Zn is obtained by filtering, washing and drying, which is the kaolin long-acting anti-disease bacteria material.

[0007] Further, in the precursor solution, the molar ratio of copper ions to zinc ions is 5-10:1.

[0008] Further, the reducing agent solution comprises A component and B component. The A component comprises one or more of ascorbic acid, sodium citrate, glucose and sodium borohydride, and the B component comprises one or more of PEG-400, polyvinylpyrrolidone, sodium dodecyl sulfate and chitosan.

[0009] Further, the concentration of the A component in the reducing agent solution is 0.08-0.12 g / ml.

[0010] Further, the concentration of the B component is 0.002-0.005 g / ml.

[0011] Further, 1 mol / L NaOH is added dropwise to adjust the pH of the system.

[0012] Further, the copper ions in the precursor solution are provided by a copper salt, and the zinc ions are provided by a zinc salt, and the anions of the copper salt and the zinc salt are one or more of acetate, nitrate, and chloride.

[0013] Further, the temperature is raised to 75-80 DEG C, and the stirring is continued for 1.5-2.5 h. The second object of the application is to provide a kaolin long-acting antibacterial material prepared by the above preparation method.

[0014] Kaolin is a natural silicate clay mineral with a large specific surface area, good adsorption performance, chemical stability, and high biocompatibility.

[0015] The application uses a hydrothermal reduction method to prepare a kaolin-based antibacterial material, and kaolin is used as a carrier. The kaolin can effectively adsorb and disperse copper ions, effectively improve the dispersity of cuprous oxide, reduce agglomeration, and strongly adsorb bacteria to the surface of the material through the rich surface hydroxyl groups. The antibacterial activity of cuprous oxide can be fully utilized, and the application performance of the antibacterial material can be improved through the stability and biocompatibility of kaolin, and the biological safety of the composite material can be improved.

[0016] In the hydrothermal reduction process, zinc ions are added for lattice doping. 2+ After the Zn ions successfully doped into the Cu2O lattice, lattice distortion and defects are introduced, and the transformation of Cu2+ ions to Cu+ and the disproportionation reaction of Cu2O are effectively inhibited. + 2+ The Cu2O can maintain its chemical state and microstructure stability in long-term use or harsh environments, thereby realizing long-acting antibacterial effect.The stability of the active cuprous oxide component can be effectively improved, and the long-acting stability of the kaolin-based antibacterial material can be realized. The addition of the B component (such as PEG) not only helps the doping of Zn, but also wraps the nanoparticles on the surface, effectively preventing the agglomeration of Cu2O / Zn particles on the surface of kaolin, making them more uniform. In addition, zinc has good antibacterial effect and can achieve synergistic antibacterial effect with cuprous oxide. The process is simple, safe and stable, has low cost, and is easy to mass produce.

[0017] The raw materials used in the application are rich in sources, safe and stable, the preparation process is simple, the preparation process does not need special protection, is environment-friendly, easy to industrialized production, has great market application potential. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 Kaol-Cu2O, Kaol-Cu2O / Zn appearance morphology diagram; Figure 2 Kaol, Kaol-Cu2O, Kaol-Cu2O / Zn XRD diagram; Figure 3 XRD diagram of the sample by aging experiment; Figure 4 Kaol, Kaol-Cu2O, Kaol-Cu2O / Zn Fourier transform infrared spectrogram; Figure 5 Fourier transform infrared spectrogram of the sample by aging experiment; Figure 6 Kaol, Kaol-Cu2O, Kaol-Cu2O / Zn antibacterial result diagram; Figure 7 Antibacterial result diagram of the sample by aging experiment. DETAILED DESCRIPTION

[0019] The following is a specific embodiment of the application and further describes the technical solutions of the application in conjunction with the drawings, but the application is not limited to these embodiments.

[0020] Example 1 Three kinds of core solutions are configured: copper-zinc precursor solution is 5.9 g (0.03 mol) Cu (CH3COO)2•H2O and 0.41 g (0.003 mol) ZnCl2 are dissolved in 75 mL of deionized water preheated to 50°C to obtain a transparent blue-green (pH≈5.2) 75 mL solution; The reducing agent solution is prepared by dissolving 10.6 g of ascorbic acid and 0.3 g of PEG-400 in 105 mL of 50°C deionized water, and the solution needs to be prepared and used immediately and avoid light throughout the process; The kaolin dispersion solution is prepared by adding 4.5 g of kaolin to 120 mL of deionized water and dispersing for 30 min under 300 W ultrasonic to obtain a homogeneous suspension.

[0021] In preparation, 120 mL of kaolin dispersion was transferred to a 500 mL beaker, and the temperature was raised to 60 °C with stirring at 300 rpm. Copper-zinc precursor solution was slowly added dropwise, followed by the addition of 1 mol / L NaOH to adjust the pH to 10, causing the solution to change from blue-green to light blue colloid (forming Cu / Zn hydroxide). Subsequently, reducing agent solution was added dropwise at a rate of 1.5 mL / min using a constant pressure funnel. The solution was observed to change sequentially from light blue to dark green to brownish-red (forming Cu2O). The temperature was maintained at 60 °C. After the addition was completed, the temperature was raised to 80 °C, the stirring rate was increased to 400 rpm, and the reaction was continued for 2 h. Finally, the product was washed twice with ethanol by centrifugation at 5000 rpm and dried to obtain the Kaol-Cu2O / Zn product.

[0022] Comparative Example 1 Kaol was obtained by crushing raw kaolin ore TL04(92).

[0023] Comparative Example 2 The copper precursor solution was prepared by dissolving 5.9 g (0.03 mol) Cu(CH3COO)2•H2O in 75 mL of preheated deionized water at 50 °C to obtain a transparent blue-green (pH≈5.2) solution in 75 mL. The reducing agent solution was prepared by dissolving 10.6 g ascorbic acid in 105 mL of deionized water at 50 °C to obtain a 105 mL solution, which should be prepared fresh and used immediately and protected from light throughout the process. The kaolin dispersion was prepared by adding 4.5 g of kaolin to 120 mL of deionized water and ultrasonically dispersing it at 300 W for 30 min to obtain a homogeneous suspension. In the experiment, 120 mL of kaolin dispersion was transferred to a 500 mL beaker and heated to 60 °C with stirring at 300 rpm. Copper precursor solution was slowly added dropwise, followed by the addition of 1 mol / L NaOH to adjust the pH to 10, causing the solution to change from blue-green to light blue colloid (forming Cu hydroxide). Subsequently, reducing agent solution was added dropwise at a rate of 1.5 mL / min using a constant pressure funnel. The solution was observed to change sequentially from light blue to dark green to brownish-red (forming Cu2O). The temperature was maintained at 60 °C. After the addition was completed, the temperature was raised to 80 °C, and the stirring rate was increased to 400 rpm. The reaction was stirred for 2 h. Finally, the product was washed twice with ethanol by centrifugation at 5000 rpm and dried to obtain the Kaol-Cu2O product.

[0024] Appearance and morphology analysis: The morphology of Kaol-Cu2O and Kaol-Cu2O / Zn is as follows Figure 1 As shown, Kaol-Cu2O is a dark yellow powder, while the product Kaol-Cu2O / Zn after Zn lattice doping is a bright yellow powder.

[0025] Stability experiment analysis: The long-term stability of Kaol-Cu2O / Zn was verified by aging experiments, which simulated the natural oxidation process of the material under normal storage conditions. The prepared Kaol-Cu2O / Zn powder was spread on a petri dish or a surface dish to form a thin layer (to increase the contact area with air). It was placed in an indoor environment to avoid direct sunlight. Samples were taken at 14 days for testing. The material sample was named Kaol-Cu2O / Zn-1. Further high-temperature accelerated aging tests were carried out. 5 g of Kaol-Cu2O / Zn sample was placed in a petri dish, and deionized water was added to wet the material, then placed in a drying oven with air atmosphere, heated at 60C, and sampled after 4 h and named Kaol-Cu2O / Zn-2. The sample was analyzed and verified by XRD, FTIR, antibacterial experiment, etc. The Kaol-Cu2O sample was subjected to high-temperature accelerated aging test and named Kaol-Cu2O-2, and the antibacterial performance was verified.

[0026] Phase analysis: The phase structure of the material was studied by XRD technology. The test results of Kaol, Kaol-Cu2O, and Kaol-Cu2O / Zn are shown in Figure 2 The curve of Kaol shows very strong and sharp diffraction peaks at 12.5° and 24.9°, which are the typical layered silicate structure (001) and (002) crystal faces of Kaol. The curve of Kaol-Cu2O shows diffraction peaks at 36.5°, 42.4°, and 61.5°, corresponding to the (111), (200), and (220) crystal faces of Cu2O, respectively, confirming the successful loading of Cu2O on the surface of Kaol. The diffraction peak position of Cu2O in Kaol-Cu2O / Zn did not shift significantly, and the addition of zinc did not form a new crystal phase, but enhanced the diffraction peak intensity of Cu2O, indicating that it may have inhibited the agglomeration of Cu2O crystal grains and promoted more uniform crystallization. It is possible that Zn 2+ partially replaced Cu⁺, but due to the difference in ionic radius (Zn 2+ 0.74 Å vs Cu⁺ 0.77 Å), the substitution amount was small and not enough to cause significant peak shift, but it may have changed the crystallization process, and the phase analysis showed that no ZnO phase was formed, indicating that no zinc oxide was generated in the reaction product.

[0027] At the same time, the XRD test results of the aging experiment samples are shown in Figure 3As shown, the main crystal phase of cuprous oxide (Cu2O) in the composite remained stable after 14 days of room temperature aging and 4 hours of 60 °C damp heat accelerated aging, and no signs of oxidation to cupric oxide (CuO) were detected. Very strong and sharp diffraction peak pairs at 12.5° and 24.9° corresponding to the characteristic peaks of kaolin appeared, indicating that the kaolin substrate was stably present in all samples. No characteristic peaks of cupric oxide (CuO) appeared in the patterns of the two aged samples (Kaol-Cu2O / Zn-1 and Kaol-Cu2O / Zn-2). The diffraction peak position and shape of Cu2O did not change significantly. The peak position did not shift, and the peak shape did not widen or split, indicating that the crystal structure of Cu2O remained intact after aging, with no phase change or severe lattice distortion, confirming the good stability of Kaol-Cu2O / Zn.

[0028] Infrared Spectroscopy Analysis: The chemical functional groups and molecular structure in the samples were detected and analyzed using a Fourier transform infrared spectrometer (FTIR). The test results are shown in Figure 4 As shown, the internal hydroxyl peak of kaolin at 3620 cm -1 in the Kaol-Cu2O sample was significantly weakened. This indicates that Cu2O nanoparticles interact with the hydroxyl groups on the surface of kaolin, possibly occupying the position of the hydroxyl groups or changing their chemical environment. The most significant evidence of the appearance of Cu-O bond is the appearance of the characteristic peak of the stretching vibration of Cu-O bond in Cu2O near ~620 cm -1 This confirms the successful loading of Cu2O on kaolin. Compared with the Kaol-Cu2O curve, the Cu-O bond absorption peak at 620 cm -1 in the Kaol-Cu2O / Zn curve is significantly enhanced and becomes wider, and the introduction of zinc may promote the formation of more and more dispersed Cu2O nanoparticles. Zinc may exist around or at the interface of Cu2O particles, forming a certain Cu-O-Zn type structure, changing the vibration mode of Cu-O bond, resulting in changes in peak strength and shape.

[0029] The test results of the aging experiment are shown in Figure 5As shown, after 14 days of room temperature aging and 4 hours of 60 °C damp heat accelerated aging, no characteristic absorption peaks of Cu(II) species such as copper oxide (CuO) or copper hydroxide (Cu(OH)2) were detected for both aged samples (Kaol-Cu2O / Zn-1 and Kaol-Cu2O / Zn-2), demonstrating that Cu2O remained well-stabilized. The framework structure (Si-O, Al-OH, O-H) of kaolinite was intact after aging, demonstrating the high stability of the composite substrate. The test results showed that the chemical structure and bonding properties of the Kaol-Cu2O / Zn composite were not detected for oxidation or structural degradation. It was confirmed that Kaol-Cu2O / Zn had good stability.

[0030] Antibacterial performance analysis: Preparation of LB (Luria-Bertani) medium: accurately weigh 20 mg of LB broth powder, add 1000 mL of distilled water into a sterilization pot, heat to dissolve, and obtain a liquid bacterial culture medium after cooling. Escherichia coli (ATCC 25922) and Staphylococcus aureus (ATCC 25923) were used as models of gram-negative and gram-positive bacteria, respectively, and the plate colony counting method was used to evaluate the antibacterial performance of the samples. Take 10 μL of bacterial stock solution, add 10 mL of liquid medium, cover with a bacterial gas-permeable membrane, and place in a constant temperature incubator at 37 °C, 180 rpm for 12 h. Take 500 μL of the 12 h incubated bacteria and dilute to 10 5~6 CFU / mL. Weigh a certain amount of sample powder and disperse it into 10 mL of liquid medium, add 500 μL of diluted bacterial solution, cover with a bacterial gas-permeable membrane, and place in a constant temperature incubator at 37 °C, 180 rpm for 4 h. Then dilute the bacterial solution to 10 4 CFU / mL, plate, and incubate in a constant temperature incubator at 37 °C for 12 h, then image and record using a gel imaging system.

[0031] The experimental samples were kaolinite Kaol, Kaol-Cu2O, Kaol-Cu2O / Zn, and the antibacterial effects of Kaol-Cu2O / Zn placed for 14 days (Kaol-Cu2O / Zn-1) and after aging treatment (Kaol-Cu2O / Zn-2 and Kaol-Cu2O-2) were tested. The experimental bacteria were Escherichia coli and Staphylococcus aureus. The results of the plate coating method experiment of kaolinite Kaol, Kaol-Cu2O, and Kaol-Cu2O / Zn are shown in Table 1. Figure 6As shown, it can be seen that the raw kaolin has almost no antibacterial effect, after loading Cu2O, the antibacterial rate of Kaol-Cu2O to E. coli reaches 99.9%, and the antibacterial effect to Staphylococcus aureus is poor. The zinc-doped Kaol-Cu2O / Zn has good antibacterial effect, and the antibacterial effect to E. coli and Staphylococcus aureus reaches 99.9%. Further evaluate the antibacterial stability of Kaol-Cu2O / Zn, after the aging experiment treatment, the experimental results of the samples Kaol-Cu2O / Zn-1 and Kaol-Cu2O / Zn-2 are as follows Figure 7 As shown, after normal temperature aging and wet heat accelerated aging, the antibacterial performance of Kaol-Cu2O-2 decreases, while the antibacterial rates of Kaol-Cu2O / Zn to E. coli and Staphylococcus aureus both reach 99.9%, and Kaol-Cu2O / Zn has high antibacterial stability.

[0032] The above not involved, applicable to the prior art.

[0033] Although some specific embodiments of the present application have been described in detail by examples, those skilled in the art should understand that the above examples are only for illustration, not for limiting the scope of the present application, and those skilled in the art can make various modifications or supplements to the described specific embodiments or replace them with similar ways, but will not deviate from the direction of the present application or exceed the scope defined by the appended claims. Those skilled in the art should understand that any modification, equivalent replacement, improvement, etc. made according to the technical essence of the present application to the above embodiments shall be included in the protection scope of the present application.

Claims

1. A method for preparing a long-acting anti-microbial material of kaolin, characterized in that, The kaolin is dispersed in deionized water, heated under stirring, and a precursor solution containing copper ions and zinc ions is slowly added dropwise, and the pH of the system is adjusted to 10, so that the solution changes from blue-green to light blue colloid; Then a reducing agent solution is added dropwise until the solution turns brown red, and the temperature is raised to 75-80 ℃, and the stirring reaction is continued, and the Kaol-Cu2O / Zn product, i.e. the long-acting anti-bacterial material of kaolin, is obtained by filtering, washing and drying.

2. The production method according to claim 1, wherein In the precursor solution, the molar ratio of copper ions to zinc ions is 5-10:

1.

3. The production method according to claim 1, wherein The reducing agent solution comprises A component and B component, the A component comprises one or more of ascorbic acid, sodium citrate, glucose and sodium borohydride, and the B component comprises one or more of PEG-400, polyvinylpyrrolidone, sodium dodecyl sulfate and chitosan.

4. The production method according to claim 2, wherein In the reducing agent solution, the concentration of the A component is 0.08-0.12 g / ml.

5. The production method according to claim 2, wherein The concentration of the B component is 0.002-0.005 g / ml.

6. The production method according to claim 1, wherein 1 mol / L NaOH is added dropwise to adjust the pH of the system.

7. The production method according to claim 1, wherein The copper ions in the precursor solution are provided by a copper salt, and the zinc ions are provided by a zinc salt, and the anions of the copper salt and the zinc salt are one or more of acetate, nitrate and chloride.

8. The production method according to claim 1, wherein The temperature is raised to 75-80 ℃, and the stirring reaction is continued for 1.5-2.5 h.

9. A long-acting anti-bacterial material of kaolin prepared by the preparation method of any one of claims 1-8.

Images