An antibacterial complex and a method of making the same

Abstract

The application discloses an antibacterial composite and a preparation method thereof. The antibacterial composite comprises a mass ratio of (8-12):(0.4-1) of sulfonic acid group modified titanium dioxide and a silicon-doped trivalent element composite. The sulfonic acid group modified titanium dioxide and the silicon-doped trivalent element composite are reacted in an organic solvent at 130-160 DEG C to obtain the antibacterial composite. The antibacterial composite prepared by the application has good dispersity of particles, excellent antibacterial performance, and can maintain the antibacterial effect for a long time after leaving the ultraviolet rays.

Description

Technical Field

[0001] This application relates to the field of antibacterial agents, and in particular to an antibacterial complex and a method for preparing the same. Background Technology

[0002] Inorganic antibacterial materials have developed rapidly in recent years, including metals such as silver, copper, and zinc, as well as some metal oxides. Among antibacterial materials that use contact reactions as their antibacterial principle, silver ions exhibit very high antibacterial strength and dominate the market. However, after killing bacteria through contact reactions, the bacteria may release pyrogenic and toxic components, such as endotoxins. Inorganic antibacterial materials that kill bacteria through photocatalysis can not only kill bacteria but also effectively degrade toxic components.

[0003] Photocatalytic antibacterial materials include titanium dioxide, cadmium sulfide, and zinc oxide, among which titanium dioxide, with its strong oxidizing properties and chemical stability, has become the most important photocatalytic antibacterial material. Titanium dioxide has an electronic structure characterized by a valence band filled with electrons and an empty conduction band. When titanium dioxide is irradiated with ultraviolet light, the electrons reach the band gap energy, exciting from the valence band to the conduction band, simultaneously generating a corresponding hole in the valence band, thus forming a photogenerated electron-hole pair. After the electrons and holes separate, they react with water or other solvents on the surface of titanium dioxide to generate free radicals such as -OH. These free radicals have strong oxidizing properties and can effectively kill bacteria and decompose them into water and carbon dioxide. Generally, the smaller the particle size of titanium dioxide, the better the antibacterial effect. However, nano-titanium dioxide, being a nanoscale material, generally suffers from poor dispersibility, severely affecting the antibacterial performance of the material. Furthermore, after the removal of ultraviolet irradiation, the separated photogenerated electron-hole pairs within titanium dioxide easily recombine, causing the titanium dioxide to lose its antibacterial ability, thus limiting the application of antibacterial materials. Summary of the Invention

[0004] To alleviate the problems of poor dispersibility and limited use of nano-titanium dioxide antibacterial materials, this application provides an antibacterial composite and its preparation method.

[0005] In one aspect, this application provides an antibacterial complex comprising a sulfonic acid-modified titanium dioxide and a silicon-doped trivalent element complex in a mass ratio of (8-12):(0.4-1); wherein the sulfonic acid-modified titanium dioxide and the silicon-doped trivalent element complex are reacted in an organic solvent at 130-160°C to obtain the antibacterial complex.

[0006] Preferably, the trivalent element includes elements such as aluminum and boron.

[0007] The aforementioned antibacterial complex not only possesses good dispersibility but also maintains its antibacterial effect for a certain period after removal from ultraviolet irradiation. Firstly, this application modifies nano-titanium dioxide with sulfonic acid groups to enhance its dispersibility in solution. The poor dispersibility of nano-titanium dioxide in solution stems from its small particle size, large specific surface area, and high specific surface energy, making it highly unstable. Furthermore, a large number of positive and negative charges accumulate on its surface, both of which attract each other, leading to agglomeration. Introducing sulfonic acid groups onto the surface of nano-titanium dioxide creates a strong dissociation property, releasing hydrogen ions that attract and bind a large number of negative charges in the solution. This creates an electrostatic repulsion between the sulfonic acid-modified titanium dioxide particles, resisting the attraction caused by the high surface energy or the accumulated positive and negative charges. This improves the dispersion of nano-titanium dioxide particles in solution, enhancing the dispersibility of the antibacterial complex and its antibacterial properties.

[0008] Titanium dioxide itself consists of a low-energy valence band and a high-energy conduction band. The valence band is filled with electrons, with a free electron concentration far exceeding the hole concentration, making it an n-type semiconductor. When tetravalent silicon crystal is doped with trivalent elements, covalent bonding results in one less electron, forming a hole, thus creating a p-type semiconductor. When the n-type semiconductor with free electrons and the p-type semiconductor with holes come into close contact, a PN junction is formed. The PN junction contains a concentration difference between electrons and holes, causing electrons and holes to diffuse to the lower concentration regions. The remaining positively and negatively charged impurity ions form a space charge region, and the positive and negative charges of these impurity ions create an internal electric field. This internal electric field acts as an energy barrier for moving holes and electrons, restricting their diffusion direction. Unless external energy is applied, they cannot overcome this barrier and can only move in one direction.

[0009] In summary, in the antibacterial complex of this application, by reacting and combining silicon-doped trivalent element complexes and titanium dioxide at high temperature to form a PN junction, the direction of its internal electron movement can be restricted. As a result, photogenerated electron-hole pairs are difficult to reset after the ultraviolet light leaves, thus prolonging the antibacterial ability of titanium dioxide and greatly alleviating the problem of limited use of antibacterial complexes.

[0010] Preferably, the mass ratio of the sulfonic acid-modified titanium dioxide to the silicon-doped trivalent element complex is (8-12):(0.5-0.7).

[0011] When there is an excessive amount of silicon-doped aluminum complex, it tends to aggregate and cover the sulfonic acid-modified titanium dioxide instead of being uniformly dispersed on the surface. This inhibits the sulfonic acid-modified titanium dioxide from absorbing ultraviolet light and generating photogenerated electron-hole pairs. Furthermore, excessive silicon-doped aluminum complex also reduces the formation of PN junctions, weakening the antibacterial effect of the antibacterial complex. However, when the mass ratio of sulfonic acid-modified titanium dioxide to silicon-doped trivalent element complex is (8-12):(0.5-0.7), the silicon-doped aluminum complex can be well dispersed on the surface of the sulfonic acid-modified titanium dioxide, generating sufficient PN junctions, thus giving the antibacterial complex a more durable antibacterial effect.

[0012] Preferably, the raw materials for the sulfonic acid-modified titanium dioxide include titanium dioxide, an amino-containing reducing agent, and sulfuric acid in a mass ratio of (1-2):(0.2-0.5):(2-4); the titanium dioxide undergoes a sulfonation reaction with the amino-containing reducing agent and sulfuric acid to obtain sulfonic acid-modified titanium dioxide.

[0013] By adopting the above technical solution, sulfonic acid groups can be grafted onto titanium dioxide, thereby improving the dispersibility of titanium dioxide in solution.

[0014] Preferably, the preparation process of the sulfonic acid-modified titanium dioxide includes the following steps:

[0015] Pre-modification: Disperse nano-titanium dioxide in hydroxyl polyethylene glycol, add 1-2% surfactant by mass of hydroxyl polyethylene glycol, stir for 5-7 hours, filter and dry to obtain pre-modified titanium dioxide;

[0016] Sulfonation: Pre-modified titanium dioxide, an amino-containing reducing agent, and sulfuric acid are added to water and stirred for 5-7 hours to obtain sulfonic acid-modified titanium dioxide.

[0017] Preferably, the amino-containing reducing agent is at least one of ammonia water and amino-based polyethylene glycol.

[0018] Preferably, the reaction temperature is 20-40℃.

[0019] Although sulfonic acid itself has good hydrophilicity, it carries a negative charge, which repels the negative charge on the surface of nano-titanium dioxide. This makes it difficult to directly graft sulfonic acid groups onto the nano-titanium dioxide surface, and direct grafting would lead to uneven distribution of the grafted sulfonic acid groups, resulting in poor dispersibility. Therefore, it is necessary to modify the nano-titanium dioxide first before grafting sulfonic acid groups. In this application, nano-titanium dioxide is first mixed with hydroxyl polyethylene glycol and a surfactant. The surfactant increases the surface activity of the nano-titanium dioxide, facilitating the grafting of abundant hydroxyl groups onto the nano-titanium dioxide surface by the hydroxyl polyethylene glycol. Then, an amino-containing reducing agent, sulfuric acid, and water are added. The amino-containing reducing agent generates a large number of strong reducing free radicals during the reaction, promoting the formation of sulfonic acid groups. Simultaneously, the amino group can also act as a precursor molecule for the sulfonic acid groups. After the sulfonic acid groups are generated, they graft onto the hydroxyl groups on the pre-modified titanium dioxide surface, resulting in more uniform and stable modification of the nano-titanium dioxide and better improvement of the dispersibility of the antibacterial complex in solution.

[0020] Preferably, the silicon-doped trivalent element complex is a silicon-doped aluminum complex.

[0021] By adopting the above technical solution, the composite material can be made more stable in use. Boron is often used to dope silicon to create p-type semiconductors. However, due to the small size of boron atoms, they are easily driven by the electric field in the PN junction, leading to lattice breakage. This results in a very low breakdown voltage of the semiconductor and a low potential barrier in the PN junction, significantly weakening the resistance to the reset of photogenerated hole-electron pairs in the antibacterial composite. Using a silicon-doped aluminum composite can alleviate this problem. The radius of aluminum atoms is similar to that of silicon atoms, allowing them to more easily replace silicon atoms and enter the crystal interior with less impact on the crystal structure. The resulting composite has a more uniform charge distribution. Furthermore, because its impact on the crystal structure is minimal, it does not cause excessive surface defects, improving the stability of the composite and making the reset of photogenerated hole-electron pairs more difficult. This allows the antibacterial composite to more effectively overcome limitations and exert its antibacterial effect.

[0022] Preferably, the silicon-doped aluminum composite is mainly prepared from raw materials comprising the following parts by weight through a sol-gel precipitation process and a calcination process:

[0023] Water glass: 2-3 parts;

[0024] Aluminum sulfate: 3-5 parts;

[0025] Acidifier: 0.3-0.5 parts.

[0026] Aluminum powder: 1.5-4 parts.

[0027] Preferably, the acidifying agent is either hydrochloric acid or sulfuric acid.

[0028] By adopting the above technical solution, water glass and aluminum sulfate sol gel are used to produce aluminum silicate gel precipitate, and then the aluminum silicate gel precipitate is calcined to generate silicon-doped aluminum composite.

[0029] Preferably, the preparation process of the silicon-doped aluminum composite includes the following steps:

[0030] Precipitation: Mix water glass, aluminum sulfate and acidifying agent, stir evenly, heat to 80-90℃ and react for 3-4 hours to obtain aluminum silicate gel;

[0031] Calcination: The aluminum silicate gel is first calcined at 500-700℃ for 2-4 hours to obtain aluminum silicate crystals. Aluminum powder is added and mixed evenly, and calcination is continued at 800-1000℃. After 5-7 hours, silicon-doped aluminum composite is obtained.

[0032] By employing the above method, a relatively uniformly doped silicon-doped aluminum composite can be obtained. Aluminum ions and hydroxide ions form aluminum hydroxide, hydrogen ions and silicate ions form silicic acid, and silicic acid and aluminum hydroxide react to form aluminum silicate gel. After the water in the gel is calcined off, high-purity aluminum powder is added and mixed evenly, followed by high-temperature calcination to induce a reduction reaction and generate the silicon-doped aluminum composite.

[0033] Preferably, the precipitation step employs a stepwise addition method, and an alkaline precipitant is added. First, water glass and an acidifying agent are mixed, then aluminum sulfate is added, and finally the alkaline precipitant is added dropwise. The alkaline precipitant includes at least one of ammonia and sodium hydroxide.

[0034] By employing the above technical solution, water glass and an acidifying agent are first mixed to generate silica gel. Then, aluminum sulfate is added, followed by the dropwise induction of an alkaline precipitant. During the precipitation process, the mixture is continuously stirred, and the dropwise induction rate of the precipitant is adjusted to control the reaction, thereby promoting the formation of aluminum silicate. Furthermore, the aluminum silicate surface will have more pores, increasing its specific surface area, thus enabling better reduction with aluminum powder to form a silicon-doped aluminum complex.

[0035] Preferably, the ratio of aluminum silicate gel to aluminum powder in the calcination step is (4-6):(0.8-1).

[0036] By adopting the above technical solution, the generated silicon-doped aluminum composite can be made more stable and the doping distribution more uniform. During the reaction, aluminum silicate mainly serves to provide the source of silicon dioxide and control the reaction rate, while aluminum powder mainly plays a reducing role, reducing silicon dioxide to a silicon-aluminum alloy. Therefore, the amount of aluminum silicate should be slightly more than that of aluminum powder. However, too much aluminum silicate may make the reaction too vigorous. Therefore, a ratio of aluminum silicate gel to aluminum powder of (4-6):(0.8-1) is both safe and produces a more uniform silicon-doped aluminum composite, which can better combine with sulfonic acid-modified titanium dioxide to form PN junctions, hindering the reset of photogenerated hole-electron pairs and more effectively solving the problem of limited use of antibacterial complexes.

[0037] Preferably, a reducing agent comprising 1-2.5% by mass of aluminum silicate gel is added during the calcination step; the reducing agent includes fluorides and alkali metal salts.

[0038] Because aluminum silicate is very stable, reducing agents can be added during the reduction reaction to facilitate its progress. Fluorides can increase the reducibility of aluminum silicate and lower the temperature required for its reduction; alkali metal salts can promote the decomposition and reduction of aluminum silicate and increase the reaction area between silicon and aluminum, both of which can improve the degree and rate of the reaction, generate higher quality silicon-doped aluminum complexes, and improve the UV-free antibacterial durability of the antibacterial complex.

[0039] Preferably, the solvent in the antibacterial complex is one of ethanol, propylene glycol, or a mixture thereof.

[0040] By employing the above technical solution, sulfonic acid-modified titanium dioxide and silicon-doped aluminum composites can be stably and effectively dispersed. After dissociation, the sulfonic acid groups attract more negative ions such as hydroxide ions, resulting in higher potentials for the sulfonic acid-modified titanium dioxide particles in solution, stronger electrostatic repulsion between particles, and better dispersibility in the prepared antibacterial composite.

[0041] Secondly, this application provides a method for preparing an antibacterial complex, comprising the following steps:

[0042] Grinding: Grinding silicon-doped aluminum semiconductors to obtain polished semiconductors with an average particle size of 50-500nm;

[0043] Combination: Sulfonic acid-modified titanium dioxide is fully dispersed in an organic solvent, a grinding semiconductor and a dispersant are added, the mixture is stirred evenly, and then poured into a hydrothermal reactor to react for 10-15 hours at a reaction temperature of 130-160℃. After centrifugation, drying and cooling, the antibacterial complex is obtained.

[0044] By employing the above technical solution, silicon-doped aluminum semiconductors are first ground into nanoscale materials, which provide a larger reaction area and better bonding when reacting with sulfonic acid-modified titanium dioxide. Then, the two are placed in a reaction vessel and reacted at high temperature. This process forms N-type and P-type regions within the crystals, promoting the formation of a PN junction and more effectively suppressing the resetting of photogenerated hole-electron pairs, thus alleviating the limitations on the use of antibacterial complexes.

[0045] The antibacterial compound of this application can be used to formulate antibacterial products such as antibacterial sprays, disinfectants, antibacterial finishing agents for fabrics, and antibacterial coatings.

[0046] In summary, this application has the following beneficial effects:

[0047] 1. This application modifies nano-titanium dioxide with sulfonic acid groups. The sulfonic acid groups have a high degree of dissociation in solution, making it easier to attract charges in the solution to their vicinity. This creates a repulsive electrostatic field between the titanium dioxide particles, which inhibits their aggregation, improves the dispersibility of the particles inside the antibacterial complex, and enhances the antibacterial performance of the antibacterial complex.

[0048] 2. This application uses a silicon-doped trivalent element complex to combine with sulfonic acid-modified titanium dioxide to form a PN junction, creating a potential barrier inside. This prevents the photogenerated hole-electron pairs generated by the sulfonic acid-modified titanium dioxide under ultraviolet light from crossing the barrier and resetting, thus enabling the antibacterial complex to maintain its antibacterial properties for a long time after the ultraviolet light is removed.

[0049] 3. This application employs a silicon-doped aluminum composite, taking advantage of the similarity in radii between aluminum and silicon atoms. This results in fewer surface defects and greater stability in the composite. The PN junction generated in the antibacterial composite has a higher potential barrier, making it more difficult for photogenerated hole-electron pairs to cross the barrier and reset. This further enhances the applicability of the antibacterial composite in environments without ultraviolet radiation. Detailed Implementation

[0050] Preparation example of sulfonic acid group modified titanium dioxide

[0051] Preparation Example 1-1: A sulfonic acid-modified titanium dioxide was prepared according to the following steps:

[0052] Pre-modification: 500g of nano titanium dioxide (D50 of 40nm) was dispersed in 2000g of hydroxyl polyethylene glycol, 1g of n-octylamine was added, and after stirring for 6 hours, the mixture was filtered and dried to obtain pre-modified titanium dioxide.

[0053] Sulfonation: 500g of pre-modified titanium dioxide, 150g of 20% ammonia water and 1000g of 98% sulfuric acid were added to 5000g of water and stirred at 30°C for 6 hours to obtain sulfonic acid-modified titanium dioxide.

[0054] Preparation Examples 1-2: A sulfonic acid-modified titanium dioxide was prepared according to the following steps:

[0055] Pre-modification: 500g of nano titanium dioxide (D50 of 40nm) was dispersed in 2000g of hydroxyl polyethylene glycol, 1g of n-octylamine was added, and after stirring for 6 hours, the mixture was filtered and dried to obtain pre-modified titanium dioxide.

[0056] Sulfonation: 500g of pre-modified titanium dioxide, 250g of 20% ammonia water and 2000g of 98% sulfuric acid were added to 5000g of water and stirred at 40°C for 6 hours to obtain sulfonic acid-modified titanium dioxide.

[0057] Preparation Examples 1-3: A sulfonic acid-modified titanium dioxide was prepared according to the following steps:

[0058] Pre-modification: 500g of nano titanium dioxide (D50 of 40nm) was dispersed in 2000g of hydroxyl polyethylene glycol, 0.5g of n-octylamine was added, and after stirring for 6 hours, the mixture was filtered and dried to obtain pre-modified titanium dioxide.

[0059] Sulfonation: 500g of pre-modified titanium dioxide, 100g of 20% ammonia water and 500g of 98% sulfuric acid were added to 5000g of water and stirred at 20°C for 6 hours to obtain sulfonic acid-modified titanium dioxide.

[0060] Preparation Examples 1-4: A sulfonic acid-modified titanium dioxide, which differs from Preparation Example 1-1 in that no pre-modification step is set, and the titanium dioxide is directly modified with sulfonic acid.

[0061] Example of silicon-doped trivalent element complex preparation

[0062] Preparation Example 2-1: A silicon-doped trivalent element complex was prepared according to the following steps:

[0063] Precipitation: Mix 250g of water glass and 100g of 37% hydrochloric acid, stir well, then add 400g of aluminum sulfate, heat to 85℃ and add 20% ammonia water dropwise until no more precipitate is formed. React for 4 hours to obtain aluminum silicate gel.

[0064] Calcination: 600g of aluminum silicate gel was calcined at 600℃ for 3 hours to obtain aluminum silicate crystals. 80g of aluminum powder was added and mixed evenly to continue the reaction. The reaction temperature was 900℃. After 6 hours, silicon-doped aluminum composite was obtained.

[0065] Preparation Example 2-2: A silicon-doped trivalent element complex was prepared according to the following steps:

[0066] Precipitation: Mix 200g of water glass and 100g of 37% hydrochloric acid, stir well, then add 500g of aluminum sulfate, heat to 85℃ and add 20% ammonia water dropwise until no more precipitate is formed. React for 4 hours to obtain trivalent silica gel.

[0067] Calcination: 600g of aluminum silicate gel was calcined at 700℃ for 3 hours to obtain aluminum silicate crystals. 120g of aluminum powder was added and mixed evenly to continue the reaction. The reaction temperature was 1000℃. After 6 hours, silicon-doped aluminum composite was obtained.

[0068] Preparation Example 2-3: A silicon-doped trivalent element complex was prepared according to the following steps:

[0069] Precipitation: Mix 300g of water glass and 50g of 37% hydrochloric acid, stir well, then add 300g of aluminum sulfate, heat to 85℃ and add 20% ammonia water dropwise until no more precipitate is formed. React for 4 hours to obtain aluminum silicate gel.

[0070] Calcination: 600g of aluminum silicate gel was calcined at 500℃ for 3 hours to obtain aluminum silicate crystals. 70g of aluminum powder was added and mixed evenly to continue the reaction. The reaction temperature was 800℃. After 6 hours, silicon-doped aluminum composite was obtained.

[0071] Preparation Example 2-4: A silicon-doped trivalent element complex was prepared according to the following steps:

[0072] Precipitation: Mix 250g water glass, 100g 37% hydrochloric acid and 400g aluminum sulfate evenly, heat to 85℃ and react for 4 hours to obtain aluminum silicate gel;

[0073] Calcination: 600g of aluminum silicate gel was calcined at 600℃ for 3 hours to obtain aluminum silicate crystals. 120g of aluminum powder was added and mixed evenly to continue the reaction. The reaction temperature was 900℃. After 6 hours, silicon-doped aluminum composite was obtained.

[0074] Preparation Examples 2-5: A silicon-doped trivalent element complex was prepared according to the following steps:

[0075] S101: Place 300g of silicon single crystal into the reactor and inject borane gas to purge air;

[0076] S102: 50g of boron oxide is reacted with 20g of hydrogen to produce boron trioxide. The boron trioxide is heated and dehydrated using a rotary evaporator, and then converted into gaseous boron oxide. The gas is then introduced into a reaction furnace and the temperature is raised to 900℃ for 5 hours. After annealing, a silicon-doped boron composite is obtained.

[0077] Preparation Examples 2-6: A silicon-doped trivalent element complex was prepared according to the following steps:

[0078] Precipitation: Mix 250g of water glass and 100g of 37% hydrochloric acid, stir well, then add 400g of aluminum sulfate, heat to 85℃ and add 20% ammonia water dropwise until no more precipitate is formed. React for 4 hours to obtain aluminum silicate gel.

[0079] Calcination: 600g of aluminum silicate gel was calcined at 500℃ for 3 hours to obtain aluminum silicate crystals. 300g of aluminum powder was added and mixed evenly to continue the reaction at 800℃. After 6 hours, silicon-doped aluminum composite was obtained.

[0080] Preparation Example 2-7, a silicon-doped trivalent element complex, differs from Preparation Example 2-1 in that 10g of sodium carbonate is added during the calcination step.

[0081] Example

[0082] Example 1: An antibacterial complex was prepared according to the following steps:

[0083] Grinding: 100g of the silicon-doped trivalent element composite obtained in Preparation Example 2-1 was ground to obtain a ground composite with an average particle size of 200nm.

[0084] Combination: 300g of sulfonic acid-modified titanium dioxide prepared in Preparation Example 1-1 was fully dispersed in 1200g of propylene glycol, 21g of the ground composite and 6g of polyethylene glycol were added, stirred evenly, poured into a hydrothermal reactor and reacted for 12 hours at a reaction temperature of 150℃. After centrifugation, drying and cooling, the antibacterial complex was obtained.

[0085] Example 2, an antibacterial complex, prepared according to the following steps:

[0086] Grinding: 100g of the silicon-doped trivalent element composite prepared in Preparation Example 2-2 was ground to obtain a grinding composite with an average particle size of 50nm.

[0087] Combination: 360g of sulfonic acid-modified titanium dioxide prepared in Preparation Examples 1-2 was fully dispersed in 900g of propylene glycol, 12g of the ground composite and 6g of polyethylene glycol were added, stirred evenly, poured into a hydrothermal reactor and reacted for 12 hours at a reaction temperature of 150℃. After centrifugation, drying and cooling, the antibacterial complex was obtained.

[0088] Example 3: An antibacterial complex was prepared according to the following steps:

[0089] Grinding: 100g of the silicon-doped trivalent element composite obtained in Preparation Example 2-3 was ground to obtain a ground composite with an average particle size of 500nm.

[0090] Combination: 240g of sulfonic acid-modified titanium dioxide prepared in Preparation Examples 1-3 was fully dispersed in 1500g of propylene glycol, 30g of the ground composite and 3g of polyethylene glycol were added, stirred evenly, poured into a hydrothermal reactor and reacted for 12 hours at a reaction temperature of 150℃. After centrifugation, drying and cooling, the antibacterial complex was obtained.

[0091] Example 4, an antibacterial complex, differs from Example 1 in that, in the bonding step, an equal amount of sulfonic acid-modified titanium dioxide prepared in Examples 1-4 is used instead of the sulfonic acid-modified titanium dioxide prepared in Example 1-1.

[0092] Example 5, an antibacterial complex, differs from Example 1 in that an equal amount of silicon-doped trivalent element complex prepared in Preparation Examples 2-4 is used instead of silicon-doped trivalent element complex prepared in Preparation Example 2-1 in the grinding step.

[0093] Example 6, an antibacterial complex, differs from Example 1 in that an equal amount of silicon-doped trivalent element complex obtained in Preparation Examples 2-5 is used instead of silicon-doped trivalent element complex obtained in Preparation Example 2-1 in the grinding step.

[0094] Example 7, an antibacterial complex, differs from Example 1 in that an equal amount of ethanol is used instead of propylene glycol in the bonding step.

[0095] Example 8, an antibacterial complex, differs from Example 1 in that an equal amount of silicon-doped trivalent element complex obtained in Preparation Examples 2-6 is used instead of silicon-doped trivalent element complex obtained in Preparation Example 2-1 in the grinding step.

[0096] Example 9, an antibacterial complex, differs from Example 1 in that an equal amount of silicon-doped trivalent element complex prepared in Preparation Examples 2-7 is used instead of silicon-doped trivalent element complex prepared in Preparation Example 2-1 in the grinding step.

[0097] Comparative Example

[0098] Comparative Example 1, an antibacterial complex, differs from Example 1 in that, in the bonding step, an equal amount of nano-titanium dioxide is used instead of the sulfonic acid-modified titanium dioxide prepared in Preparation Example 1-1.

[0099] Comparative Example 2, an antibacterial complex, differs from Example 1 in that, in the grinding step, an equal amount of sulfonic acid-modified titanium dioxide prepared in Preparation Example 1 is used instead of the silicon-doped trivalent element complex prepared in Preparation Example 2-1.

[0100] Comparative Example 3, an antibacterial complex, was prepared according to the following steps:

[0101] Grinding: 100g of the silicon-doped trivalent element composite obtained in Preparation Example 2-1 was ground to obtain a ground composite with an average particle size of 200nm.

[0102] Combination: 300g of sulfonic acid-modified titanium dioxide prepared in Preparation Example 1-1 was fully dispersed in 1200g of propylene glycol, 21g of the grinding composite and 6g of polyethylene glycol were added, stirred evenly, and then centrifuged and dried to obtain the antibacterial composite.

[0103] Comparative Example 4, an antibacterial complex, was prepared according to the following steps:

[0104] Grinding: 150g of the silicon-doped trivalent element composite obtained in Preparation Example 2-1 was ground to obtain a ground composite with an average particle size of 200nm.

[0105] Combination: 300g of sulfonic acid-modified titanium dioxide prepared in Preparation Example 1-1 was fully dispersed in 1200g of propylene glycol, 80g of the ground composite and 6g of polyethylene glycol were added, stirred evenly, poured into a hydrothermal reactor and reacted for 12 hours at a reaction temperature of 150℃. After centrifugation, drying and cooling, the antibacterial complex was obtained.

[0106] Performance testing

[0107] Experiment 1: Antibacterial Performance Test

[0108] Test subjects: Examples 1-10 and Comparative Examples 1-3.

[0109] Sample preparation: 1 kg of antibacterial complex sample was mixed with 20 kg of water-based acrylate and stirred evenly to obtain an antibacterial finishing agent. Each group of antibacterial finishing agents was divided into two samples and prepared into a coating film with a thickness of 1 mm.

[0110] Test Methods: The antibacterial properties of the samples prepared in the examples and comparative examples were tested according to GB / T21866-2008 "Determination of Antibacterial Properties and Antibacterial Effects of Antibacterial Coatings (Films)". The selected test bacteria were Staphylococcus aureus and Escherichia coli. The inhibition rate of the first sample was tested after 10 minutes of UV irradiation. The inhibition rate of the second sample was tested after 10 minutes of UV irradiation, followed by 30 minutes of rest in the dark. The UV irradiation intensity for both samples was 70 μW / cm². 2 The distance between the ultraviolet light and the sample was 1m, and the test results are shown in Table 1.

[0111] Experiment 2: Dispersion Test Method: The zeta potential of the examples and comparative examples was measured using an electrophoresis apparatus. The larger the absolute value of the zeta potential, the stronger the electrostatic repulsion between particles and the better the dispersion. The test results are shown in Table 1.

[0112] Table 1. Antibacterial properties and zeta potential of antibacterial complexes

[0113]

[0114]

[0115] Analysis of experimental results:

[0116] 1. As can be seen from Examples 1-4 and Comparative Example 1, and in conjunction with Table 1, this application improves the dispersibility of particles in the antibacterial complex by modifying titanium dioxide with sulfonic acid groups and performing pre-modification before modification. This may be because sulfonic acid groups have a high degree of dissociation in water, releasing a large number of positively charged hydrogen ions. These ions attract a large number of negatively charged particles in the solution, creating a strong electrostatic repulsion between the sulfonic acid-modified titanium dioxide particles. This resists the attraction that causes nanoparticle aggregation, increasing the dispersibility of titanium dioxide in the solution. Furthermore, pre-modifying titanium dioxide increases its surface activity, allowing the sulfonic acid groups to be grafted onto the titanium dioxide surface more uniformly and stably, further enhancing the dispersibility of particles in the antibacterial complex.

[0117] 2. As can be seen from Examples 1-3, Examples 4-9, and Comparative Example 2, and in conjunction with Table 1, this application significantly improves the antibacterial performance of the antibacterial complex after the removal of ultraviolet radiation by combining a silicon-doped trivalent element complex with sulfonic acid-modified titanium dioxide. This is likely because titanium dioxide itself is an m-type semiconductor, while the silicon-doped trivalent element complex is a p-type semiconductor. When the two are combined, a PN junction can be formed at their interface, creating a potential barrier inside. Electrons and holes can only move in one direction and it is difficult for them to cross the barrier and move in the opposite direction. This makes it difficult for the photogenerated electron-hole pairs generated by titanium dioxide under ultraviolet irradiation to reset, allowing them to continue generating free radicals for a period of time after the removal of ultraviolet radiation, thus enhancing the antibacterial performance of the antibacterial complex after the removal of ultraviolet radiation and alleviating the problem of limited use of the antibacterial complex.

[0118] 3. As can be seen from Examples 1-3 and Example 6, and Table 1, using a silicon-doped aluminum composite as a p-type semiconductor can better improve the antibacterial performance of the antibacterial composite after exposure to ultraviolet light. This may be because silicon and aluminum atoms have similar atomic radii, and doping does not cause excessive surface defects in the crystal, resulting in a more stable semiconductor. Furthermore, when combined with sulfonic acid-based titanium dioxide to form a PN junction, the internal potential barrier is higher and more stable, better addressing the limitations on the use of antibacterial composites.

[0119] 4. Based on Examples 1-3 and Comparative Example 3, and referring to Table 1, it can be seen that even without heating the sulfonic acid-modified silica and silicon-doped trivalent element complex, simply dispersing them in solution does not significantly reduce the antibacterial ability of the antibacterial complex after it is removed from ultraviolet light. This may be because without heating, the two cannot react and combine; only after combination can a PN junction be formed to hinder the reset of photogenerated hole-electron pairs.

[0120] 5. Based on Examples 1-3, 5, and 8-9, and referring to Table 1, it can be seen that when preparing silicon-doped aluminum composites, using a stepwise addition method during aluminum silicate precipitation, controlling the amount of aluminum powder used during aluminum silicate calcination, and adding alkali metal salts can improve the uniformity and stability of the generated silicon-doped aluminum composites. This may be because the stepwise addition method can control the formation of aluminum silicate and significantly increase its specific surface area, leading to better reaction with aluminum powder; controlling the amount of aluminum powder and adding alkali metal salts can promote the decomposition and reduction of aluminum silicate, generating higher-quality silicon-doped aluminum composites. These composites can form more stable PN junctions with sulfonic acid-modified titanium dioxide, improving the antibacterial properties of the antibacterial complex after exposure to ultraviolet light.

[0121] 6. Based on Examples 1-3 and Comparative Example 4, and referring to Table 1, it can be seen that when the mass proportion of silicon-doped trivalent element complexes in the antibacterial composite is too high, the antibacterial performance of the antibacterial composite decreases. This may be because when the content of silicon-doped trivalent element complexes is excessive, they tend to aggregate and cover the sulfonate-modified titanium dioxide, inhibiting the sulfonate-modified titanium dioxide from absorbing ultraviolet light and generating photogenerated electron-hole pairs, and reducing the formation of PN junctions, thus weakening the antibacterial effect of the antibacterial composite.

[0122] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. An antibacterial complex, characterized in that, The mixture comprises a sulfonic acid-modified titanium dioxide and a silicon-doped trivalent element complex in a mass ratio of (8-12):(0.4-1); the sulfonic acid-modified titanium dioxide and the silicon-doped trivalent element complex are reacted in an organic solvent at 130-160℃ to obtain an antibacterial complex; wherein the raw materials for the sulfonic acid-modified titanium dioxide include titanium dioxide, an amino-containing reducing agent, and sulfuric acid in a mass ratio of (1-2):(0.2-0.5):(2-4); The preparation process of the sulfonic acid-modified titanium dioxide includes the following steps: Pre-modification: Disperse nano-titanium dioxide in hydroxyl polyethylene glycol, add 1-2% surfactant by mass of hydroxyl polyethylene glycol, stir for 5-7 hours, filter and dry to obtain pre-modified titanium dioxide; Sulfonation: Pre-modified titanium dioxide, an amino-containing reducing agent, and sulfuric acid are added to water and stirred for 5-7 hours to obtain sulfonic acid-modified titanium dioxide; The silicon-doped trivalent element complex is a silicon-doped aluminum complex; The preparation process of the silicon-doped aluminum composite includes the following steps: Precipitation: Mix water glass, aluminum sulfate and acidifying agent, stir evenly, heat to 80-90℃ and react for 3-4 hours to obtain aluminum silicate gel; Calcination: The aluminum silicate gel is first calcined at 500-700℃ for 2-4 hours to obtain aluminum silicate crystals. Aluminum powder is added and mixed evenly, and calcination is continued at 800-1000℃. After 5-7 hours, silicon-doped aluminum composite is obtained.

2. The antibacterial complex according to claim 1, characterized in that, The silicon-doped aluminum composite is prepared from the following raw materials in parts by weight through a sol-gel precipitation process and a calcination process: Water glass: 2-3 parts; Aluminum sulfate: 3-5 parts; Acidifying agent: 0.3-0.5 parts; Aluminum powder: 1.5-4 parts.

3. The antibacterial complex according to claim 1, characterized in that, The precipitation step employs a stepwise addition method and includes the addition of an alkaline precipitant. Specifically, water glass and an acidifying agent are mixed, aluminum sulfate is added, and finally, an alkaline precipitant is added dropwise. The alkaline precipitant includes at least one of ammonia and sodium hydroxide.

4. A method for preparing an antibacterial complex according to any one of claims 1-3, characterized in that, Includes the following steps: Grinding: The silicon-doped aluminum composite is ground to obtain a grinding composite with an average particle size of 50-500 nm; Combination: Sulfonic acid-modified titanium dioxide is fully dispersed in an organic solvent, and the grinding composite and dispersant are added. The mixture is stirred evenly and poured into a hydrothermal reactor to react for 10-15 hours at a reaction temperature of 130-160℃. After centrifugation, drying, and cooling, the antibacterial composite is obtained.

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