A mechanical bactericidal coating for dynamic and static water environments, its preparation method, and its application.

Abstract

This invention discloses a mechanical bactericidal coating for both dynamic and static water environments, its preparation method, and its applications. Specifically, it relates to the field of bactericidal coating technology, including the preparation of titanium dioxide nanopillar surfaces via a hydrothermal method and the preparation of a graphite carbon nitride-modified titanium dioxide coating via a high-temperature method. The mechanical bactericidal coating provided by this invention not only exhibits bactericidal properties at liquid-gas interfaces but also demonstrates excellent bactericidal ability in flowing water, overcoming the limitation of its application to solid-liquid interfaces.

Description

Technical Field

[0001] This invention relates to a mechanical bactericidal coating for dynamic and static water environments, its preparation method, and its application, belonging to the field of bactericidal coating technology. Background Technology

[0002] In recent years, nanopillar array surfaces have attracted attention due to their excellent antibacterial properties. Research on nanopillar array surfaces was initially inspired by the surface of cicada wings. When nanopillars come into contact with bacteria, the contact surface causes mechanical deformation of the bacteria. When the deformation reaches a certain limit, the bacterial structure is destroyed, thus achieving a bactericidal effect. Compared to traditional chemical sterilization, nanopillar surfaces destroy bacterial structures through physical action, avoiding the potential development of drug resistance in bacteria over long-term exposure. Simultaneously, in aquatic environments, it avoids chemical pollution from the bactericidal substances themselves caused by long-term chemical reactions. Therefore, the unique physical bactericidal properties of nanopillar array surfaces make them promising for broad applications in industrial pollution control and medical sterilization.

[0003] To clarify the mechanism of bacterial sterilization on the surface of nanopillars, a large number of studies have focused on exploring this through a combination of experiments and numerical simulations. For example, Valei et al. (Nano Letters, 20(2020), 5720-5727) demonstrated that external mechanical forces are key to the destruction of bacterial structures. For instance, on gas and liquid surfaces, capillary action increases the normal force, thereby causing bacterial structural damage. Pogodin et al. (Biophysical Journal, 104(2013), 835-840) developed a bacterial nanopillar interaction model, which suggests that the extension of bacteria between nanopillars is key to bacterial structural destruction.

[0004] Titanium dioxide is widely used due to its mechanical stability and chemical inertness. Chris et al. (Sci Rep, 5(2015), 16817) simulated the wings of dragonflies to create titanium nanopillar arrays, which showed excellent bactericidal behavior against Staphylococcus aureus; Terje et al. (Mater Lett, 167(2016), 22-26) prepared anisotropic titanium nanostructure surfaces, which increased the inactivation ability against Escherichia coli by 40% compared to smooth surfaces; Diu et al. (Sci Rep, 4(2014), 7122) prepared titanium dioxide nanostructure surfaces and found that the surfaces had significant bactericidal effects against Escherichia coli, Bacillus subtilis, etc.

[0005] However, the current nanopillar sterilization surface still has the following problems: the preparation process is complicated; it can only act on a single solid-water interface for sterilization, and its sterilization effect in flowing water is not obvious; the sterilization surface strength is low and the repeatability is poor. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a mechanical bactericidal coating for dynamic and static water environments, its preparation method and application, which not only exhibits bactericidal performance at the liquid-gas interface, but also has excellent bactericidal ability in flowing water, overcoming the limitation of its action to the solid-liquid interface.

[0007] To achieve the above objectives, the present invention is implemented using the following technical solution:

[0008] In a first aspect, the present invention provides a method for preparing a mechanically bactericidal coating for dynamic and static water environments, comprising:

[0009] Titanium dioxide nanopillars were prepared using a hydrothermal method.

[0010] Glucose and urea are mixed and placed in a reactor for firing, with excess nitrogen gas introduced to obtain graphitic carbon nitride. During this process, the surface of titanium dioxide nanopillars is placed downwind of the heating zone, allowing graphitic carbon nitride to naturally settle onto the surface of the titanium dioxide nanopillars. After washing with water and alcohol, a titanium dioxide coating modified with graphitic carbon nitride is obtained, which is a mechanical bactericidal coating for dynamic and static water environments.

[0011] Optionally, the surface of titanium dioxide nanopillars is prepared by a hydrothermal method, including:

[0012] The elemental titanium plate was pretreated to obtain the pretreated elemental titanium plate.

[0013] The pretreated elemental titanium plate was ultrasonically treated in acetone solution, dried, then reacted in an alkaline solution, removed, washed and dried, then acid-washed in sulfuric acid solution, washed with water, and finally heat-treated to obtain the surface of titanium dioxide nanopillars.

[0014] Optionally, the pretreatment includes cutting, polishing, and grinding the elemental titanium plate.

[0015] Optionally, the acetone solution has a mass percentage of 90-99%, and the ultrasonic treatment conditions include ultrasonic treatment at a rotation speed of 1200-1800 r / min for 12-15 min.

[0016] Optionally, the molar concentration of the alkaline solution is 1.2~1.5 mol / L, and the reaction conditions include reacting at 300~400℃ for 2~4 h.

[0017] Optionally, the washing and drying operation includes rinsing with deionized water and then drying, alternating the operation at least twice, and the drying conditions are drying at a temperature of 400~500℃ for 2~4 hours.

[0018] Optionally, the molar concentration of the sulfuric acid solution is 1~1.2 mol / L, and the acid washing and water washing are alternated at least twice; the heat treatment conditions are at 500~550℃ for at least 4 hours.

[0019] Optionally, the mass ratio of glucose to urea is 3~5:1, and the firing temperature is 550~650℃.

[0020] Secondly, the present invention provides a mechanical bactericidal coating for dynamic and static water environments, which is prepared by any of the above-described methods for preparing mechanical bactericidal coatings for dynamic and static water environments.

[0021] Thirdly, the present invention provides an application of the above-mentioned mechanical sterilization coating in dynamic and static water environments. The mechanical sterilization coating in dynamic and static water environments performs mechanical sterilization in dynamic or static water environments through a titanium dioxide nanopillar array, and its sterilization efficiency reaches more than 95%.

[0022] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0023] The mechanical bactericidal coating for dynamic and static water environments provided in this application is a titanium dioxide coating modified with graphite carbon nitride. It not only exhibits bactericidal properties at the liquid-gas interface, but also has excellent bactericidal ability in flowing water, overcoming the defect that bactericidal coatings in the prior art are limited to the liquid-gas interface.

[0024] This invention prepares titanium dioxide nanopillar surfaces via a hydrothermal method. The preparation process is simple and has practical industrial production value. Furthermore, the graphite carbon nitride modified titanium dioxide coating prepared in this application has high mechanical strength and can be reused. Attached Figure Description

[0025] Figure 1 This is a schematic SEM image of the mechanical bactericidal coating for dynamic and static water environments prepared in Example 1 of the present invention.

[0026] Figure 2 The diagram shows the experimental results of the mechanical bactericidal coatings prepared in dynamic and static water environments in Example 1 of the present invention, the unmodified graphite carbon nitride titanium dioxide nanopillar coating prepared in Comparative Example 1, the titanium dioxide smooth coating prepared in Comparative Example 2, and the ordinary pipe material prepared in Comparative Example 3, respectively, applied to inactivate Escherichia coli under pipe flow conditions.

[0027] Figure 3This diagram illustrates the experimental results of inactivating Bacillus subtilis when the mechanical bactericidal coatings prepared in dynamic and static water environments as described in Example 1 of the present invention, the unmodified graphitic carbon nitride titanium dioxide nanopillar coating prepared in Comparative Example 1, the titanium dioxide smooth coating prepared in Comparative Example 2, and the hydraulic concrete prepared in Comparative Example 4 are applied to the surface of hydraulic concrete. Detailed Implementation

[0028] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention. Example

[0029] The method for preparing mechanical bactericidal coatings for dynamic and static water environments provided in this invention includes the following steps:

[0030] Step 1: Preparation of titanium dioxide nanopillars surface via hydrothermal method

[0031] The pure titanium plate was cut into 20mm diameter pieces and then polished.

[0032] A titanium nanoplate was immersed in a 99% acetone solution and sonicated at 1500 rpm for 12 minutes, followed by drying at 400°C for 2.5 hours. Then, it was added to a 1.5 mol / L sodium hydroxide solution and placed in an oven at 300°C for 2 hours. After the reaction, it was removed, rinsed with deionized water, and dried at 500°C. This process of rinsing and drying was repeated three times, alternating between the two. Next, it was acid-washed with a 1 mol / L sulfuric acid solution to ensure the removal of non-titanium metal cations from the surface. It was then rinsed again with deionized water. This process of acid washing and rinsing was repeated three times, alternating between the two. Finally, it was heat-treated at 500°C for 4 hours to obtain the surface of titanium dioxide nanopillars.

[0033] Step 2: Prepare a graphite carbon nitride-modified titanium dioxide coating using a high-temperature method.

[0034] Urea and glucose were mixed at a mass ratio of 4:1 and placed in a reactor for firing at a controlled temperature of 600℃. The titanium dioxide surface obtained in step (1) was placed downwind of the reaction heating zone, and excess nitrogen gas was introduced into the reactor. The graphite carbon nitride was heated and fired, and then settled onto the titanium dioxide surface under the action of the gas flow. The obtained material was repeatedly washed with water and alcohol, and dried to obtain a graphite carbon nitride-modified titanium dioxide nanopillar coating (CN-TiN), which is a mechanical bactericidal coating for both dynamic and static water environments.

[0035] SEM images of the prepared graphite carbon nitride modified titanium dioxide nanopillar coating (mechanical bactericidal coating for dynamic and static water environments) are shown below. Figure 1 As shown.

[0036] Comparative Example 1:

[0037] This comparative example provides an unmodified graphitic carbon nitride titanium dioxide nanopillar coating (TiN), the preparation method of which includes the following steps:

[0038] The pure titanium plate was cut into 20mm diameter pieces and then polished.

[0039] A pure titanium plate was immersed in a 99% acetone solution and sonicated at 1500 rpm for 12 minutes, followed by drying at 400°C for 2.5 hours. Then, it was added to a 1.5 mol / L sodium hydroxide solution and placed in an oven at 300°C for 2 hours. After the reaction, it was removed, rinsed with deionized water, and dried at 500°C. This process of rinsing and drying was repeated three times, alternating between the two. Next, it was acid-washed with a 1 mol / L sulfuric acid solution to ensure the removal of non-titanium metal cations from the surface. It was then rinsed again with deionized water. This process of acid washing and rinsing was repeated three times, followed by heat treatment at 500°C for 4 hours. The final result was a titanium dioxide nanopillar surface, i.e., an unmodified graphitic carbon nitride titanium dioxide nanopillar coating.

[0040] Comparative Example 2:

[0041] This comparative example provides a smooth titanium dioxide (Ti) coating, the preparation method of which includes the following steps:

[0042] The pure titanium plate was cut into 20mm diameter pieces and then polished.

[0043] A pure titanium plate was placed in a 99% acetone solution and ultrasonically treated at 1500 r / min for 12 min, and then dried at 400℃ for 2.5 h to obtain a smooth titanium dioxide coating (Ti).

[0044] Comparative Example 3:

[0045] This comparative example provides a common pipe material, which is ordinary PVC.

[0046] Comparative Example 4:

[0047] This comparative example provides a common hydraulic concrete, which is made of ordinary silicate cement and sand and gravel raw materials, which are purchased from Conch Cement Co., Ltd.

[0048] The performance of the titanium dioxide nanopillar coatings (mechanical bactericidal coatings for dynamic and static water environments) obtained in Example 1 and Comparative Examples 1-4 is analyzed below:

[0049] Performance Analysis Experiment 1:

[0050] The graphite carbon nitride modified titanium dioxide nanopillar coating (mechanical bactericidal coating for dynamic and static water environments) obtained in Example 1 was applied to inactivate Escherichia coli under pipe flow conditions. The specific operation is as follows:

[0051] Escherichia coli was cultured in nutrient broth at 30℃~40℃ until the logarithmic growth phase. After high-speed centrifugation, the supernatant was filtered off, and the sample was washed with buffer. After repeated centrifugation and washing five times, the sample was resuspended in 1.0% NaCl solution to obtain a solution with a pH of approximately 7 and a concentration of approximately 8×10⁻⁶. 4 Escherichia coli suspension at cfu / mL.

[0052] Take 500 mL of Escherichia coli suspension and put it into the water storage tank. Turn on the water pump and adjust the normal pipe flow rate. The liquid flows out from the outlet pipe and then flows into the circulation through the inlet pipe. The liquid flows through the prepared graphite carbon nitride modified titanium dioxide coating. The dark environment is controlled to avoid possible photocatalytic reactions of titanium dioxide and graphite carbon nitride and to simulate the actual pipe flow. The water is circulated and samples are collected at the outlet valve at 0.5 h, 1 h, 2 h and 3 h respectively.

[0053] The entire treatment process was repeated three times to verify the reusability of the mechanically sterilized surface. The collected water samples were diluted, and E. coli were counted using the agar plate counting method to obtain the experimental results.

[0054] The above experimental procedures were repeated, with the only difference being that the graphite carbon nitride modified titanium dioxide coating was replaced with an unmodified graphite carbon nitride titanium dioxide nanopillar coating (TiN), a smooth titanium dioxide coating (Ti), and ordinary pipe material, resulting in three sets of comparative experimental results.

[0055] All results are taken from the third repeated operation, such as Figure 2 As shown, by Figure 2 It can be seen that the reduction in the number and frequency of viable colonies in the three comparative experiments were both less than those of the graphite carbon nitride modified titanium dioxide nanopillar coating (CN-TiN). Furthermore, no viable colonies were observed in the experimental samples in the water storage tank after the graphite carbon nitride modified titanium dioxide nanopillar coating (CN-TiN) had been applied for 3 hours, indicating that its bactericidal effect was significant and demonstrating that the mechanical bactericidal coating has excellent bactericidal performance in dynamic water environments.

[0056] Under dark conditions, the bactericidal effect of the graphite carbon nitride modified titanium dioxide nanopillar coating is better than that of the unmodified graphite carbon nitride titanium dioxide nanopillar coating. This is because the modification of graphite carbon nitride alters the bactericidal mechanism of the nanopillar surface in a moving water environment, making it more suitable for bactericidal action in moving water. In addition to the tip effect of the nanopillars, the modification of graphite carbon nitride provides additional forces in their contact with bacteria, making the cell walls easier to break down and thus achieving the bactericidal effect.

[0057] Performance Analysis Experiment 2:

[0058] The graphite carbon nitride modified titanium dioxide nanopillar coating (mechanical bactericidal coating for dynamic and static water environments) obtained in Example 1 was applied to the surface of hydraulic concrete to inactivate Bacillus subtilis. The specific operation is as follows:

[0059] The culture method for Bacillus subtilis is similar to that for Escherichia coli, and will not be elaborated upon here. The concentration of Bacillus subtilis obtained is 1×10⁻⁶. 7 cfu / mL.

[0060] The graphite carbon nitride-modified titanium dioxide nanopillar coating obtained in Example 1 was applied to the surface of hydraulic concrete to simulate actual scenarios such as slope protection. 500 mL of Bacillus subtilis suspension was placed in a water tank, and a UV lamp was turned on to allow the surface solution to evaporate automatically. Samples were taken every 2 hours, with three replicate samples taken each time. The average value was calculated, and the ratio of the Bacillus subtilis concentration Ct to the original concentration C0 was determined.

[0061] The above experimental procedures were repeated, with the only difference being that the graphite carbon nitride modified titanium dioxide coating was replaced with an unmodified graphite carbon nitride titanium dioxide nanopillar coating (TiN), a titanium dioxide smooth coating (Ti), and ordinary hydraulic concrete, resulting in three sets of comparative experimental results.

[0062] Experimental results are as follows Figure 3 As shown, by Figure 3 It can be seen that the reduction in the number and frequency of viable colonies in the three sets of comparative experiments were both less than those of the titanium dioxide nanopillar coating modified with graphite carbon nitride (CN-TiN), indicating that the mechanical bactericidal coating has excellent bactericidal performance in a still water environment.

[0063] Under light conditions, the bactericidal effect of the graphite carbon nitride modified titanium dioxide nanopillar coating is better than that of the unmodified graphite carbon nitride titanium dioxide nanopillar coating. This is because the modification of graphite carbon nitride may promote the photocatalytic reaction under light conditions, thereby increasing its bactericidal performance.

[0064] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a mechanical sterilization coating for dynamic and static water environments, characterized by, The application relates to a preparation method of a dynamic and static water environment mechanical sterilization coating. The preparation method comprises the following steps: The titanium plate is pretreated to obtain a pretreated titanium plate; The pretreated titanium plate is placed in an acetone solution for ultrasonic treatment, dried, then placed in an alkaline solution for reaction, washed and dried after being taken out, then placed in a sulfuric acid solution for pickling, washed with water, and finally heat-treated to obtain a titanium dioxide nanocolumn surface; Glucose and urea are mixed and placed in a reaction furnace for calcination, the mass ratio of the glucose and the urea is 3-5:1, the calcination temperature is 550-650 DEG C, and excess nitrogen is introduced, graphite carbon nitride is obtained through calcination, in the process, the titanium dioxide nanocolumn surface is placed under the wind of a heating area, so that the graphite carbon nitride is naturally settled on the titanium dioxide nanocolumn surface, and after washing with water and alcohol, a graphite carbon nitride modified titanium dioxide coating is obtained, which is the dynamic and static water environment mechanical sterilization coating.

2. The method for preparing a mechanical sterilization coating in dynamic and static water environments according to claim 1, characterized in that, The pretreatment comprises cutting, polishing and grinding the titanium plate.

3. The method of claim 1, wherein the method further comprises the step of: 3-1) adding a surfactant to the mixture of step 2-1) or 2-2) to form a mixture of step 3-1). The mass percentage of the acetone solution is 90-99%, and the ultrasonic treatment conditions comprise ultrasonic treatment at a rotation speed of 1200-1800 r / min for 12-15 min.

4. The method of claim 1, wherein the method further comprises the step of: 4-1) adding a surfactant to the solution of step 3-1) or 3-2) to form a surfactant solution. The molar concentration of the alkaline solution is 1.2-1.5 mol / L, and the reaction conditions comprise reaction at 300-400 DEG C for 2-4 h.

5. The method of claim 1, wherein the method further comprises the step of: 5.

1. applying a mechanical sterilization coating to the surface of the object to be sterilized. The washing and drying operation comprises washing with deionized water and drying alternately at least twice, and the drying conditions are drying at 400-500 DEG C for 2-4 h.

6. The method of claim 1, wherein the method further comprises the step of: 6-1) applying a mechanical sterilization coating to the surface of the object to be sterilized. The molar concentration of the sulfuric acid solution is 1-1.2 mol / L, the pickling and washing are alternated at least twice, and the heat treatment conditions are at least 4 h at 500-550 DEG C.

7. A mechanical sterilization coating for dynamic and static water environments, characterized in that, The dynamic and static water environment mechanical sterilization coating is prepared through the preparation method of any one of claims 1-6.

8. Use of a mechanical sterilization coating in a dynamic and static water environment as claimed in claim 7, characterized in that, The dynamic and static water environment mechanical sterilization coating performs mechanical sterilization in a dynamic or static water environment through the titanium dioxide nanocolumn array, and the sterilization efficiency reaches more than 95%.

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