A PDA / BiOCl photocatalytic material, preparation method and application

Abstract

The invention discloses a PDA / BiOCl photocatalytic material, a preparation method and an application, and belongs to the technical field of antibacterial agents. The preparation method of the invention comprises the following steps: step 1, preparing an aqueous solution containing a bismuth source to obtain a clear solution A; step 2, dissolving a halogen source in a buffer solution, controlling the solution pH to 7.5-9.5, standing at room temperature, and obtaining a solution B; step 3, slowly dropping the clear solution A obtained in step 1 into the solution B obtained in step 2, continuously stirring the reaction, obtaining a precipitate, washing, and drying to obtain a PDA / BiOCl photocatalytic material, wherein the PDA in the obtained photocatalytic material is a polymer network structure, which is coated on the BiOCl petal-shaped particles, and the photocatalytic material has a higher visible light utilization efficiency and exhibits excellent photocatalytic antibacterial performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of antimicrobial agents, and more specifically, relates to a PDA / BiOCl photocatalytic material, a preparation method and an application thereof. Background Art

[0002] Staphylococcus aureus, also known as golden staphylococcus, belongs to the genus Staphylococcus and is a common Gram-positive bacterium that is widely found in air, water, dust, and human and animal excrement. Staphylococcus aureus is also a foodborne pathogenic microorganism that often parasitizes the skin, nasal cavity, and throat of humans and animals, and can cause a variety of diseases in humans and animals, such as pseudomembranous colitis, sepsis, and septicemia, which seriously threaten the life safety of humans and animals. In the past treatment, antibiotics were the most common antibacterial agents, but bacteria and fungi have become increasingly resistant to existing drugs, and the abuse of antibiotics threatens public health. Semiconductor photocatalytic materials synthesized with the assistance of biological reagents have excellent light absorption properties and high levels of reactive oxygen species (ROS) production, and are considered to be a promising new bactericidal strategy. Therefore, it is of great significance to develop a non-toxic and inexpensive photocatalytic material with antibacterial effect to replace the use of antibiotics.

[0003] Bismuth (Bi) compounds are abundant in nature, cheap and easy to obtain. BiOCl prepared from bismuth salts is a non-toxic semiconductor with strong skin adhesion and a certain pearlescent effect. It can produce various types of reactive oxygen species when excited by light in an oxygen-containing wet environment. However, the band gap of pure BiOCl is relatively wide (~3.2eV), and its bactericidal effect under visible light is not obvious. Through surface modification, its band structure can be adjusted to enhance its visible light bactericidal ability.

[0004] After searching, the patent publication number is CN113318759A, the publication date is August 31, 2021, and the name of the invention is a dopamine-mediated bismuth oxychloride photocatalyst and its preparation method and application. The invention discloses a flower ball-shaped dopamine-mediated bismuth oxychloride photocatalyst, and its preparation method includes the following steps: First, dissolve the bismuth source Bi(NO3)3·5H2O in deionized water, and control the pH value of the solution system to 1.5-4 by adding glacial acetic acid. The above-mentioned solution is slowly added to a dopamine hydrochloride aqueous solution with a concentration of 1-8 mg / mL, and the molar ratio of the halogen source to the bismuth source is controlled to (0.2-2.4): 1, and stirred at room temperature until the reaction is complete. The precipitate is washed with ethanol and deionized water by centrifugation, and then dried to obtain dopamine-mediated bismuth oxychloride. However, the catalyst prepared by this method is a pure bismuth oxychloride photocatalyst, and dopamine is finally eluted as a template, and pure bismuth oxychloride cannot be used as a bactericide in antibacterial.

[0005] The patent publication number is CN108525702A, and the publication date is September 14, 2018. The invention provides a supported bismuth oxychloride photocatalyst for sewage treatment and a preparation method. The clay mineral vermiculite is first added to anhydrous ethanol for ultrasonic dispersion to obtain a suspension, and then dopamine hydrochloride is added and mixed evenly and refluxed to obtain a dopamine-modified vermiculite clay mineral material, which is mixed with bismuth nitrate and ethylene glycol solution of polyvinyl pyrrolidone, ammonium chloride, sodium hydroxide and deionized water and then subjected to microwave hydrothermal reaction to obtain a dopamine-modified vermiculite clay mineral supported bismuth oxychloride photocatalyst. The patent publication number is CN113828301A, and the publication date is December 24, 2021. The invention discloses a composite photocatalytic material, a preparation method and an application thereof. The preparation method of the composite photocatalytic material comprises the following steps: weighing dopamine and bismuth oxybromide at a mass ratio of 1:20 to 1:100, and then polymerizing the dopamine on the surface of the bismuth oxybromide to prepare a polydopamine / bismuth oxybromide composite intermediate; calcining the polydopamine / bismuth oxybromide composite intermediate at a temperature of 400°C to 500°C to obtain a polydopamine / bismuth oxybromide / bismuth oxide composite material as the composite photocatalytic material. The prepared photocatalytic material has high photocatalytic activity and good catalytic stability. The disadvantage is that the invention uses bismuth oxybromide as a substrate to load PDA, and adopts a two-step synthesis method. The binding force between PDA and bismuth oxybromide is weak, and the preparation process involves multiple steps and the method is complicated.

[0006] The patent publication number is CN114849741A, the publication date is August 5, 2022, and the name of the invention is a photocatalytic antibacterial composite material, its preparation method and application. The preparation method of the photocatalytic antibacterial composite material includes the following steps: after the bismuth source solution and dopamine hydrochloride are mixed and reacted, BiOCl is obtained; BiOCl is dispersed in a copper salt solution, and an alkaline solution and a reducing agent are added to obtain BiOCl / Cu2O; polydopamine is mixed with BiOCl / Cu2O, and after incubation in a water bath, the product is separated, and the obtained BiOCl / Cu2O-PDA is used in the fields of optical / electrical devices, gas-sensitive materials, biological antibacterial, marine antifouling or photocatalysis. However, Cu2O is toxic and is not suitable as a bactericide to replace antibiotics. Moreover, it is unstable in an acidic liquid phase and is prone to disproportionation reactions. Summary of the invention

[0007] 1. Problem to be solved

[0008] In view of the problem that existing photocatalytic materials have poor bactericidal performance, the present invention provides a PDA / BiOCl photocatalytic material, a preparation method and an application thereof. The PDA / BiOCl photocatalytic material prepared by the method has high photocatalytic antibacterial performance and shows good biological antibacterial effect in the sterilization of Staphylococcus aureus.

[0009] 2. Technical solution

[0010] In order to solve the above problems, the technical solution adopted by the present invention is as follows:

[0011] The present invention discloses a method for preparing a PDA / BiOCl photocatalytic material, which specifically comprises the following steps:

[0012] Step 1: preparing a solution A containing a bismuth source: preparing an aqueous solution containing a bismuth source to obtain a clear solution A;

[0013] Step 2: Prepare solution B containing a halogen source: dissolve the halogen source in a Tris-HCl buffer solution, control the pH to 7.5-9.5, and stand at room temperature to obtain solution B; wherein the dopamine monomer is allowed to stand in the Tris-HCl buffer solution for 5-15 minutes and mixed evenly.

[0014] Step 3, preparation of PDA / BiOCl photocatalytic material: slowly add the clear solution A obtained in step 1 to the solution B obtained in step 2, continue stirring to react, obtain a precipitate, wash and dry, and obtain PDA / BiOCl photocatalytic material. Wherein, the molar ratio of Bi to dopamine hydrochloride in the bismuth source is 1: (2-12); the reaction temperature is 20-40°C, the reaction time is 0.5-6h, after washing the precipitate, the drying temperature is 40-80°C, and the drying time is 4-16h. Wherein, the drying temperature can achieve the drying of the precipitate.

[0015] Furthermore, the bismuth source is one or more of BiCl3 or Bi(NO3)3·5H2O, preferably Bi(NO3)3·5H2O. When Bi(NO3)3·5H2O is selected as the bismuth source, Bi(NO3)3·5H2O is dissolved in glacial acetic acid to obtain a clear solution A, wherein the concentration of Bi(NO3)3 is preferably 3.18 mM. When dilution is required, the solution is fixed to 1 L with deionized water and ultrasonically treated for 10 min. For another example, when BiCl3 is selected as the bismuth source, BiCl3 is dissolved in concentrated hydrochloric acid. In addition, all other methods in the prior art that can form a clear solution of a bismuth source can be used.

[0016] Furthermore, the types of the dopamine salt containing a halogen source and the buffer solution are selected according to the required halogen. When synthesizing BiOCl, the dopamine salt containing a halogen source is dopamine hydrochloride. The buffer solution is a Tris-HCl buffer solution, i.e., a tris(hydroxymethyl)aminomethane hydrochloride buffer solution, and the pH of the solution is controlled at 7.5-9.5, so that dopamine is oxidized and self-polymerized under alkaline conditions to form polydopamine PDA. The concentration of the Tris-HCl buffer solution is 10 mM, and the concentration of the dopamine hydrochloride is preferably 8 mg / mL.

[0017] In the PDA / BiOCl photocatalytic material prepared by the above method, the BiOCl is a petal-shaped particle with a multi-level structure, and the PDA is a polymer network structure coated on the BiOCl. Furthermore, the particle size of the BiOCl is 3 to 6 μm.

[0018] The prepared PDA / BiOCl photocatalytic material can be used in the sterilization of heat-sensitive bacteria, such as the sterilization of Staphylococcus aureus. The inhibition rate of Staphylococcus aureus reaches 96.29% within 2 hours of visible light irradiation.

[0019] BiOCl is a non-toxic semiconductor photocatalytic material that can generate photogenerated electrons and holes when excited by light, which can activate oxygen molecules or water adsorbed on its surface to form O2 - , H2O2, ·OH and other active species. However, the band gap of pure BiOCl is relatively wide (~3.2eV), and the bactericidal effect under visible light is not obvious. Therefore, one of the main purposes of the present invention is to adjust its band structure through surface modification and enhance its visible light bactericidal ability.

[0020] Polydopamine (PDA) is a biomimetic material generated by the polymerization of dopamine, inspired by mussel foot silk adhesion protein. It has strong wet adhesion to various substrates and is now widely used in the fields of biomaterials, energy and catalysts. PDA is rich in catechol and secondary amine structures. In its unique oxidation chemical process, it can transfer electrons through phenol quinone isomers to produce reactive oxygen species (ROS) or hydrogen peroxide, which can denature cell membrane proteins, destroy bacterial cell membrane structures, and cause bacterial death. It has gradually become a new type of biological antibacterial material. However, the photothermal conversion efficiency of pure polydopamine is limited.

[0021] Therefore, the present invention adopts a "one-pot" green preparation strategy to synthesize a PDA / BiOCl photocatalytic material with a multi-level structure in situ at low temperature, wherein dopamine hydrochloride is a halogen source and also serves as a template for forming BiOCl. During the preparation process, a solution B containing dopamine hydrochloride is mixed with a solution A containing a bismuth source. On the one hand, the dopamine monomer in the solution can be used as a template and a halogen source for forming BiOCl to induce crystallization to form BiOCl. On the other hand, under alkaline conditions of pH=7.5-9.5, polydopamine is gradually polymerized to form polydopamine, which is in situ adsorbed on BiOCl to obtain a PDA-coated BiOCl photocatalytic material. The method can be used to synthesize PDA / BiOCl photocatalytic material in situ at low temperature, and PDA is tightly adsorbed on the surface of BiOCl, which is beneficial to the transmission of photogenerated carriers at the interface between PDA and BiOCl.

[0022] The BiOCl of the present invention is a multi-level BiOCl photocatalytic material formed by self-assembly of two-dimensional (2D) nanosheets using PDA as a template and a halogen source. The BiOCl prepared by the method has a large specific surface area and is rich in oxygen vacancies in the structure, so its spectral absorption range is wider than that of pure BiOCl, and can be excited by visible light. At the same time, the light utilization efficiency is significantly improved due to multiple reflections of the incident light in the multi-level structure. It is tightly combined with PDA, and the large specific surface area and rich oxygen vacancies of BiOCl allow the catalyst to have more metal ion anchoring positions or adsorption centers, which is conducive to combining with atoms (N, C, O) in the PDA structure, and the catechol and primary amine groups in the PDA structure give it good adhesion and metal coordination, thereby improving adsorption performance. The prepared PDA is coated on the surface of BiOCl with a polymer network structure, which not only increases the contact area between PDA and BiOCl, but also facilitates the transmission of photogenerated carriers at the interface, and at the same time increases the roughness of the catalyst surface, and improves the adsorption of the photocatalytic material to the reaction substrate; in addition, the PDA molecular structure has an indole structure and a variety of non-covalent interactions, which is conducive to the formation of a large number of planar conjugated structures and donor-acceptor structures, so that PDA has light response and photothermal conversion performance in the near-infrared region, and is coated on the BiOCl surface. The conjugated π system in the PDA molecule is conducive to broadening the light response range of BiOCl, promoting the separation of photogenerated carriers, and improving the performance of the photocatalytic material, thereby generating more active oxygen species and improving the bactericidal performance of the catalyst. Further, for heat-sensitive bacteria, PDA has a wide absorption spectrum and excellent photothermal conversion performance, thereby achieving a bactericidal effect. The present invention compounds PDA with BiOCl, widens the light response range of BiOCl, and improves the light absorption rate, which is conducive to improving the photothermal conversion efficiency of PDA, thereby effectively inhibiting the growth of heat-sensitive bacteria. The surface electrical properties of the modified PDA / BiOCl changed, which in turn affected its photocatalytic bactericidal performance.

[0023] In summary, BiOCl is a non-toxic semiconductor photocatalytic material that can produce various types of active oxygen species when excited by light in an aerobic wet environment, which can be used for photocatalytic sterilization. Polydopamine has good biocompatibility and antibacterial properties, strong wet adhesion and abundant chemical reaction sites. The PDA / BiOCl photocatalytic material with a multi-level structure prepared by a "one-pot" green preparation strategy and low-temperature in-situ synthesis can be applied to the field of antibacterial agents, especially for thermosensitive bacteria. The prepared PDA / BiOCl photocatalytic material has a wider light response range, higher catalytic performance and photothermal conversion efficiency, and thus exhibits better bactericidal ability under visible light irradiation. The catalyst prepared by the present invention can be applied to the fields of sterilization and antifouling.

[0024] 3. Beneficial effects

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) The present invention adopts a "one-pot" green synthesis strategy, and the desired material can be prepared by reaction at room temperature with good reproducibility. Compared with the step-by-step method, the PDA and BiOCl prepared by the present invention are more tightly combined, which is conducive to the transmission of photogenerated carriers at the interface between PDA and BiOCl;

[0027] (2) In the PDA / BiOCl photocatalytic material of the present invention, the conjugated π system in the PDA molecule is conducive to broadening the light response range of BiOCl, promoting the separation of photogenerated carriers, improving the performance of the photocatalytic material, and then generating more active oxygen species, thereby improving the bactericidal performance of the catalyst;

[0028] (3) In the PDA / BiOCl photocatalytic material of the present invention, the light response range of BiOCl is broadened and the light absorption rate is improved, which is beneficial to improving the light-to-heat conversion efficiency of PDA, thereby effectively inhibiting the growth of heat-sensitive bacteria;

[0029] (4) The BiOCl of the present invention is coated with PDA on the surface, and the PDA presents a polymer network structure, which can effectively enhance the adsorption of the catalyst;

[0030] (5) The BiOCl prepared by the present invention uses PDA as a template and a halogen source to prepare a multi-level structure BiOCl semiconductor formed by self-assembly of two-dimensional nanosheets. The BiOCl prepared by this method has a large specific surface area, is rich in oxygen vacancies in the structure, has a wider spectral absorption range than pure BiOCl, and significantly improves the efficiency of light utilization;

[0031] (5) The PDA / BiOCl photocatalytic material of the present invention has a wider light absorption range and light utilization efficiency than pure BiOCl. Within 2 hours of xenon lamp irradiation, the sterilization rate of Staphylococcus aureus reaches 96.29%;

[0032] (6) The raw materials of the present invention are all low-toxic, pollution-free reagents, which reduce harm to the human body and harm to the environment, and are suitable for the field of biomedicine. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The technical solution of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments, but it should be understood that these drawings are designed only for explanation purposes and are not intended to limit the scope of the present invention. In addition, unless otherwise specified, these drawings are intended only to conceptually illustrate the structural configurations described herein and are not necessarily drawn to scale.

[0034] Figure 1 This is a SEM image of BiOCl prepared in Example 1 of the present invention;

[0035] Figure 2 XRD patterns of BiOCl prepared in Example 1 and PDA / BiOCl photocatalytic materials prepared in Example 3 of the present invention;

[0036] Figure 3 This is a SEM image of the PDA / BiOCl photocatalytic material prepared in Example 3 of the present invention;

[0037] Figure 4 This is a FESEM image of the PDA / BiOCl photocatalytic material prepared in Example 3 of the present invention;

[0038] Figure 5 TEM image of the PDA / BiOCl photocatalytic material prepared in Example 3 of the present invention;

[0039] Figure 6 This is the Uv-Vis spectrum of the PDA / BiOCl photocatalytic material prepared in Example 3 of the present invention;

[0040] Figure 7 Figure 1 is an antibacterial effect diagram, wherein Figure A is a blank test group irradiated with visible light for 2 hours; Figure B is a blank test group irradiated with visible light for 6 hours; Figure C is a PDA-added visible light irradiation for 2 hours; Figure D is a BiOCl-added visible light irradiation for 2 hours; and Figure E is an antibacterial effect diagram of the PDA / BiOCl prepared in Example 3 irradiated with visible light for 2 hours. DETAILED DESCRIPTION

[0041] The following detailed description of exemplary embodiments of the present invention refers to the accompanying drawings, which form a part of the description, and in which exemplary embodiments of the present invention that can be implemented are shown as examples. Although these exemplary embodiments are described in sufficient detail to enable those skilled in the art to implement the present invention, it should be understood that other embodiments can be implemented and various changes can be made to the present invention without departing from the spirit and scope of the present invention. The following more detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but is only for the purpose of illustrating and not limiting the description of the characteristics and features of the present invention, so as to propose the best mode for performing the present invention and to enable those skilled in the art to implement the present invention. Therefore, the scope of the present invention is limited only by the appended claims.

[0042] Example 1

[0043] A method for preparing a PDA material comprises the following steps:

[0044] Step 1, prepare solution A containing bismuth source: dissolve Bi(NO3)3·5H2O with glacial acetic acid, and prepare a 3.18 mM colorless solution with deionized water to obtain clear solution A;

[0045] Step 2, prepare solution B containing halogen source: weigh 96 mg of dopamine hydrochloride, dissolve it in 12 mL of Tris-HCl buffer solution, adjust pH=4, and obtain solution B;

[0046] Step 3, preparation of PDA / BiOCl photocatalytic material: slowly add 70.8 mL of the clear solution A obtained in step 1, stir at room temperature for 30 min, and then centrifuge (7000 rpm, 5 min) to separate the precipitate, wash with deionized water and ethanol to remove the unreacted solvent, and then place the obtained precipitate in an oven at 80°C for 12 h to obtain a BiOCl material, the morphology of which is as follows: Figure 1 shown.

[0047] Example 2

[0048] A method for preparing a PDA material comprises the following steps:

[0049] 96 mg of dopamine hydrochloride was accurately weighed and dissolved in 12 mL of 10 mM Tris-HCl buffer solution, and the pH was controlled to be 8.5. The dopamine monomer was polymerized in the Tris-HCl buffer solution, and the polymerization time was controlled to be 2 h. After the reaction, the precipitate was separated by centrifugation and washed with deionized water and ethanol to remove the unreacted solvent. The precipitate was placed in an oven at 80° C. and dried for 12 h to obtain a PDA material.

[0050] Example 3

[0051] A method for preparing a PDA / BiOCl photocatalytic material comprises the following steps:

[0052] Step 1, prepare solution A containing bismuth source: dissolve Bi(NO3)3·5H2O with glacial acetic acid, and prepare a 3.18 mM colorless solution with deionized water to obtain clear solution A;

[0053] Step 2: Prepare solution B containing a halogen source: add 96 mg of dopamine hydrochloride to 12 mL of Tris-HCl buffer solution, control the pH to 8.5, and let stand for 5 minutes to obtain solution B;

[0054] Step 3, preparation of PDA / BiOCl photocatalytic material: 70.8 mL of clear solution A was slowly added dropwise to solution B obtained in step 2, and stirred continuously at 25°C for 30 min. After the reaction was completed, the precipitate was obtained by centrifugation (7000 rpm, 5 min), and then washed twice with deionized water and ethanol respectively to remove the unreacted solvent. Finally, the obtained precipitate was placed in an oven at 80°C and dried for 10 h to obtain PDA / BiOCl photocatalytic material.

[0055] The structure, morphology and optical properties of the prepared PDA / BiOCl photocatalytic material are shown in Figure 1-6 As shown, Figure 2 The XRD patterns of BiOCl obtained in Example 1 and PDA / BiOCl photocatalysts prepared in Example 3 show that all diffraction peaks of the catalysts have a good correspondence with the tetragonal phase of pure BiOCl (PDF#82-0485), indicating that the synthesized catalysts all have a basic BiOCl crystal structure. In addition, no characteristic peak of PDA is observed in the XRD spectrum of the PDA / BiOCl photocatalyst, which is due to the weak characteristic diffraction peak of low-crystallinity PDA, which is masked by the strong diffraction peak of BiOCl. It also shows that the modification of PDA does not affect the lattice structure of the carrier BiOCl.

[0056] Figure 1 is the SEM image of BiOCl. Figure 3 and Figure 4 The following are the SEM and FESEM images of PDA / BiOCl, respectively. It can be seen from the figure that both PDA / BiOCl and BiOCl are petal-shaped particles formed by self-assembly of two-dimensional nanosheets, with a particle size of 3 to 6 μm. However, the nanosheets that make up the BiOCl particles are sparse and have a smooth surface, while the nanosheets of PAD / BiOCl are dense and have a fuzzy texture. This is because, in the synthesis of BiOCl, dopamine hydrochloride only acts as a template and halogen source. It exists as a monomer molecule under acidic conditions of pH = 4, does not undergo polymerization, and is easily eluted; while in the preparation of PDA / BiOCl, the solution is controlled to be alkaline, DOPA polymerizes to form PDA, and is deposited on the two-dimensional BiOCl nanosheets. From Figure 4 It was confirmed that the surface of the two-dimensional nanosheets that make up the PAD / BiOCl particles is rough and has attachments. Furthermore, transmission electron microscopy was used to further confirm that PDA was successfully loaded on the BiOCl surface, such as Figure 5 Shown is the TEM image of the PDA / BiOCl photocatalytic material, from which the lattice fringes belonging to BiOCl and the lattice fringes of PDA attached to its edges can be clearly distinguished.

[0057] Figure 6 The Uv-Vis graphs of the prepared PDA / BiOCl and BiOCl materials are shown in Figure 1. Compared with the absorption curve of BiOCl, the absorption edge of the PDA / BiOCl photocatalytic material prepared in Example 1 has a red shift, indicating that BiOCl responds to visible light and the introduction of PDA broadens the light absorption range of BiOCl.

[0058] Example 4

[0059] The steps of Example 4 are substantially the same as those of Example 3, except that the polymerization time of the PDA is different. The steps specifically include the following steps:

[0060] Step 1, prepare solution A containing bismuth source: dissolve BiCl3·5H2O with concentrated hydrochloric acid, and prepare a 3.18 mM colorless solution with deionized water to obtain clear solution A;

[0061] Step 2, prepare solution B containing halogen source: add 96 mg of dopamine hydrochloride into 12 mL of Tris-HCl buffer solution to control pH=7.5, let stand for 10 min, and obtain solution B;

[0062] Step 3, preparation of PDA / BiOCl photocatalytic material: 70.8 mL of clear solution A was slowly added dropwise to solution B obtained in step 2, and stirred continuously at 20°C for 2 h. After the reaction was completed, the precipitate was obtained by centrifugation (7000 rpm, 5 min), and then washed twice with deionized water and ethanol respectively to remove the unreacted solvent. Finally, the obtained precipitate was placed in an oven at 80°C and dried for 10 h to obtain PDA / BiOCl photocatalytic material.

[0063] Example 5

[0064] The steps of Example 5 are substantially the same as those of Example 3, except that the polymerization time of the PDA is different. The steps specifically include the following steps:

[0065] Step 1, prepare solution A containing bismuth source: dissolve BiCl3·5H2O with concentrated hydrochloric acid, and prepare a 3.18 mM colorless solution with deionized water to obtain clear solution A;

[0066] Step 2: Prepare solution B containing a halogen source: add 96 mg of dopamine hydrochloride to 12 mL of Tris-HCl buffer solution, control the pH to 9.5, and let stand for 15 minutes to obtain solution B;

[0067] Step 3, preparation of PDA / BiOCl photocatalytic material: 70.8 mL of clear solution A was slowly added dropwise to solution B obtained in step 2, and stirred continuously at 40°C for 4 h. After the reaction was completed, the precipitate was obtained by centrifugation (7000 rpm, 5 min), and then washed twice with deionized water and ethanol respectively to remove the unreacted solvent. Finally, the obtained precipitate was placed in an oven at 80°C and dried for 10 h to obtain PDA / BiOCl photocatalytic material.

[0068] Example 6

[0069] The steps of Example 6 are basically the same as those of Example 3, except that the polymerization time of the PDA is different. The steps specifically include the following steps:

[0070] Step 1, preparing a solution A containing a bismuth source: dissolving Bi(NO3)3·5H2O in glacial acetic acid, and preparing a 3.18 mM colorless solution with deionized water to obtain a clear solution A;

[0071] Step 2: Prepare solution B containing a halogen source: add 96 mg of dopamine hydrochloride to 12 mL of Tris-HCl buffer solution, control the pH to 8.5, and let stand for 5 min to obtain solution B;

[0072] Step 3, preparation of PDA / BiOCl photocatalytic material: 70.8 mL of clear solution A was slowly added dropwise to solution B obtained in step 2, and stirred continuously at 20°C for 6 h. After the reaction was completed, the precipitate was obtained by centrifugation (7000 rpm, 5 min), and then washed twice with deionized water and ethanol respectively to remove the unreacted solvent. Finally, the obtained precipitate was placed in an oven at 80°C and dried for 10 h to obtain PDA / BiOCl photocatalytic material.

[0073] Example 7

[0074] The steps of Example 7 are basically the same as those of Example 3, except that the amount of PDA added is different. The steps specifically include the following steps:

[0075] Step 1, preparing a solution A containing a bismuth source: dissolving Bi(NO3)3·5H2O in glacial acetic acid, and preparing a 3.18 mM colorless solution with deionized water to obtain a clear solution A;

[0076] Step 2: Prepare solution B containing a halogen source: add 288 mg of dopamine hydrochloride to 12 mL of Tris-HCl buffer solution, control the pH to 8.5, and let stand for 5 min to obtain solution B;

[0077] Step 3, preparation of PDA / BiOCl photocatalytic material: 70.8 mL of clear solution A was slowly added dropwise to solution B obtained in step 2, and stirred continuously at 20°C for 30 min. After the reaction, the precipitate was separated by centrifugation (7000 rpm, 5 min), and the unreacted solvent was removed by washing with deionized water and ethanol. The obtained precipitate was then placed in an oven and dried at 80°C for 12 h to obtain PDA / BiOCl photocatalytic material.

[0078] Example 8

[0079] The steps of Example 8 are basically the same as those of Example 3, except that the amount of PDA added is different. The steps specifically include the following steps:

[0080] Step 1, preparing a solution A containing a bismuth source: dissolving Bi(NO3)3·5H2O in glacial acetic acid, and preparing a 3.18 mM colorless solution with deionized water to obtain a clear solution A;

[0081] Step 2: Prepare solution B containing a halogen source: add 384 mg of dopamine hydrochloride to 12 mL of Tris-HCl buffer solution, control the pH to 8.5, and let stand for 5 min to obtain solution B;

[0082] Step 3, preparation of PDA / BiOCl photocatalytic material: 70.8 mL of clear solution A was slowly added dropwise to solution B obtained in step 2, and stirred continuously at 20°C for 30 min. After the reaction, the precipitate was separated by centrifugation (7000 rpm, 5 min), and the unreacted solvent was removed by washing with deionized water and ethanol. The obtained precipitate was then placed in an oven and dried at 80°C for 12 h to obtain PDA / BiOCl photocatalytic material.

[0083] Example 9

[0084] The steps of Example 9 are basically the same as those of Example 3, except that the amount of PDA added is different. The method specifically includes the following steps:

[0085] Step 1, preparing a solution A containing a bismuth source: dissolving Bi(NO3)3·5H2O in glacial acetic acid, and preparing a 3.18 mM colorless solution with deionized water to obtain a clear solution A;

[0086] Step 2: Prepare solution B containing a halogen source: add 480 mg of dopamine hydrochloride to 12 mL of Tris-HCl buffer solution, control the pH to 8.5, and let stand for 5 min to obtain solution B;

[0087] Step 3, preparation of PDA / BiOCl photocatalytic material: 70.8 mL of clear solution A was slowly added dropwise to solution B obtained in step 2, and stirred continuously at 20°C for 30 min. After the reaction, the precipitate was separated by centrifugation (7000 rpm, 5 min), and the unreacted solvent was removed by washing with deionized water and ethanol. The obtained precipitate was then placed in an oven and dried at 80°C for 12 h to obtain PDA / BiOCl photocatalytic material.

[0088] Example 10

[0089] Staphylococcus aureus was selected as the target bacterial species to test the bactericidal performance of the photocatalytic materials prepared in Examples 1-3. The testing process was as follows:

[0090] Activation of the original bacterial liquid and cultivation of the strain: Take out 100 μL of the original bacterial liquid and transfer it to LB liquid culture medium. Then, place the LB liquid culture medium in a shaker at 37°C and 200 rpm for 12 to 18 hours. Then, use a disposable inoculation loop to dip a small amount of activated bacterial liquid (Staphylococcus aureus) and streak it on a clean LB solid culture medium at 37°C for 24 hours. Then, use a disposable inoculation loop to pick up a single colony that appears in the LB solid culture medium and inoculate it into the LB liquid culture medium for another 24 hours. Mark the cultured bacterial liquid as the mother bacterial liquid and determine the total number of unit colonies.

[0091] Sample antibacterial experiment: Under sterile conditions, 7.5 mg of PDA, BiOCl, and PDA / BiOCl (Example 3) were mixed with 1 mL of 10 3 CFU (colony forming units) / mL of bacterial solution were placed together in a sterile quartz tube containing 9mL LB liquid culture medium. Under magnetic stirring, 500W xenon lamp was illuminated for 2h to take samples. 50μL of the sample and bacterial solution mixture was transferred and evenly spread on the LB solid culture medium, and cultured at 37℃400rpm for 24h. The growth of bacterial colonies was observed, the number of colonies growing on the surface of the solid culture medium was counted by a counter, and the bactericidal rate of the sample was calculated by formula (I). The bacterial solution without adding samples was set as the control group, and the bactericidal ability of PDA samples, PDA@BiOCl samples, and BiOCl samples was explored respectively. The bactericidal ability was evaluated by the inhibition rate, and the calculation method is as follows:

[0092]

[0093] Test performance results such as Figure 7 As shown, Figure 7 Figure 2 is the antibacterial effect of PDA, BiOCl, PDA / BiOCl (Example 1) and blank control group after 2h of xenon light irradiation. In the blank group without antibacterial material, a total of 378 colonies were recorded on the solid LB medium inoculated with the bacterial solution after 2h of light irradiation and cultured for 24h (see Figure 7 A); There were too many colonies of Staphylococcus aureus growing on the LB medium inoculated 6 hours after illumination to be counted (see Figure 7 B). This shows that without adding antimicrobial agents, Staphylococcus aureus can still multiply rapidly when exposed to sunlight. Figure 7C, D and E), PDA and BiOCl both showed certain antibacterial ability, but the antibacterial effect of PDA / BiOCl photocatalyst was better. Figure E shows that after the bacterial solution containing PDA / BiOCl photocatalyst was irradiated with xenon light for 2 hours, the number of Staphylococcus aureus colonies on the solid LB medium inoculated and cultured for 24 hours was only 14, and the sterilization rate under light was 96.26%.

[0094] The above experimental results show that the PDA / BiOCl photocatalytic material prepared in the present invention can effectively inhibit the growth and reproduction of Staphylococcus aureus under visible light, and is a potential option for killing drug-resistant bacteria.

Claims

1. An application of a PDA / BiOCl photocatalytic material, characterized in that: The PDA / BiOCl photocatalytic material is used in the sterilization of Staphylococcus aureus, and the preparation method of the PDA / BiOCl photocatalytic material comprises the following steps: Step 1, preparing solution A containing a bismuth source: preparing an aqueous solution containing a bismuth source to obtain a clear solution A; Step 2, preparing a solution B containing a halogen source: dissolving the halogen source in a buffer solution, wherein the halogen source is dopamine hydrochloride, controlling the solution pH to 7.5-9.5, and standing at room temperature to obtain a solution B; Step 3, preparing PDA / BiOCl photocatalytic material: slowly dropwise adding the clear solution A obtained in step 1 into the solution B obtained in step 2, continuously stirring the reaction to obtain a precipitate, washing and drying the precipitate to obtain a PDA / BiOCl photocatalytic material; The PDA / BiOCl photocatalytic material comprises PDA and BiOCl, wherein the PDA is a polymer network structure coated on the BiOCl, and the BiOCl is a petal-shaped particle with a multi-level structure, and the particle size of the BiOCl is 3-6 μm.

2. The use of a PDA / BiOCl photocatalytic material according to claim 1, characterized in that: The bismuth source is one or more of BiCl3 or Bi(NO3)3•5H2O.

3. The use of a PDA / BiOCl photocatalytic material according to claim 2, characterized in that: In step 2, the buffer solution is a Tris-HCl buffer solution.

4. The use of a PDA / BiOCl photocatalytic material according to claim 3, characterized in that: The molar ratio of Bi element to dopamine hydrochloride in the bismuth source is 1:(2-12).

5. The use of a PDA / BiOCl photocatalytic material according to claim 1, characterized in that: In step 3, the reaction temperature is 20-40 ° C, the reaction time is 0.5-6h, the drying temperature is 40-80 ° C, and the drying time is 4-16 h.

6. The use of a PDA / BiOCl photocatalytic material according to claim 1, characterized in that: The PDA / BiOCl photocatalytic material has an antibacterial rate of 96.29% on Staphylococcus aureus after irradiation with visible light for 2 hours.

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