Graphene oxide titanium dioxide photocatalytic antibacterial and mildew-proof agent

Abstract

The application discloses a graphene titanium dioxide photocatalytic antibacterial and mildew-proof agent and a preparation method and application thereof, and belongs to the technical field of photocatalytic functional materials. The mildew-proof agent takes an anatase type nitrogen-doped titanium dioxide as a base, adopts a hydrothermal method combined with an impregnation method, sequentially loads graphene oxide (GO) and aniline, and constructs a composite photocatalytic system of an electron assistant cooperation + aniline functionalization. The GO serves as an electron transmission medium, greatly improves visible light catalytic activity, the aniline modifies the graphene through pi-pi conjugation, and the material is endowed with selective degradation capacity for azo organic pollutants, and simultaneously achieves the effects of broad-spectrum antibiosis and long-acting mildew-proof. The application has the advantages of easy-to-obtain raw materials, simple and controllable preparation process, strong stability of the composite system, excellent recycling performance, workability under ultraviolet light and visible light, efficient degradation of organic pollutants such as formaldehyde and dyes, inhibition of the growth of mildew and bacteria, and wide application in scenes such as building coatings, textiles, wooden products, indoor air and water purification, and the like. The application has the dual functions of environmental governance and antibacterial and mildew-proof, and has high practical value.

Description

Technical Field

[0001] This invention relates to the fields of photocatalytic functional materials and antibacterial and antifungal materials, specifically to the application of a nitrogen-doped titanium dioxide-graphene oxide-aniline ternary composite photocatalytic antibacterial and antifungal agent. Background Technology

[0002] With the rapid development of the home decoration, textile printing and dyeing, and wood processing industries, the problem of excessive levels of volatile and water-soluble organic pollutants such as formaldehyde and azo dyes in indoor environments has become prominent. Damp environments are prone to the growth of pathogenic bacteria and molds such as Escherichia coli, Staphylococcus aureus, Aspergillus niger, and Penicillium. Long-term exposure can damage human respiratory and skin health. Therefore, the development of integrated functional materials that combine the degradation of organic pollutants, broad-spectrum antibacterial properties, and long-lasting anti-mold effects has become an urgent need in the industry.

[0003] Titanium dioxide (TiO2) is the most commercially mature photocatalytic material. Among them, the anatase crystal form has the best photocatalytic activity. However, pure titanium dioxide material has two inherent defects: (1) The intrinsic band gap is large, and it can only respond to ultraviolet light. Its utilization rate of natural light and indoor visible light is extremely low; (2) The recombination rate of electron-hole pairs generated by photoexcitation is fast, and the photon efficiency is low. When used alone, its performance in removing formaldehyde, degrading dyes, and antibacterial and antifungal properties does not meet the actual use requirements.

[0004] Existing modified titanium dioxide schemes mostly employ single nitrogen doping modification or single graphene oxide composite modification: nitrogen doping can only narrow the band gap and broaden the visible light response range, but cannot effectively separate photogenerated carriers; graphene oxide (GO) can act as an electron transport channel to suppress electron-hole recombination, but it has no specific adsorption sites and no selective degradation ability for azo dyes.

[0005] Most existing commercial antibacterial and antifungal products are formulated with organic antibacterial agents, which have problems such as easy decomposition at high temperatures, easy dissolution in water, short service life, and secondary pollution after degradation. Conventional photocatalytic powders have weak interfacial bonding with water-based resins and textile fibers, and are prone to peeling and failure after brushing or impregnation. At present, the industry lacks an integrated ternary composite photocatalytic powder that can efficiently catalyze and directionally degrade azo pollutants under visible light, has long-lasting broad-spectrum antibacterial and antifungal effects, good powder dispersibility, and is adaptable to various processing technologies. Summary of the Invention

[0006] The purpose of this invention is to provide a composite material that combines multiple functions, including photocatalytic degradation of organic pollutants, selective degradation of azo dyes, broad-spectrum antibacterial properties, and long-lasting antifungal effects. It solves the problems of high photogenerated carrier recombination rate, weak visible light response, and low catalytic efficiency associated with pure titanium dioxide; it overcomes the drawbacks of traditional antibacterial and antifungal chemicals, such as easy secondary pollution and short shelf life; the preparation process is simple, it can be mass-produced, and it can be applied in fields such as coatings, textiles, and air purification.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0008] A graphene-titanium dioxide photocatalytic antibacterial and antifungal agent is composed of a main catalytic component and a functional additive; the main catalytic component is a functionalized graphene-titanium dioxide composite material, wherein the functionalized graphene-titanium dioxide is based on nitrogen-doped titanium dioxide, with graphene oxide and aniline sequentially loaded on the surface of titanium dioxide.

[0009] The proportions of each component by mass are as follows: 85-95 parts nitrogen-doped titanium dioxide, 0.08-0.12 parts graphene oxide, 2.4-6 parts aniline, and 3-10 parts functional additives; wherein the mass ratio of aniline to graphene oxide is controlled at 30:1-50:1.

[0010] The nitrogen-doped titanium dioxide is anatase with a particle size of 5–30 nm; the graphene oxide has a particle size of 10–300 nm, ≤5 layers, a purity of 99.5%, and a specific surface area of ​​500 m² / g; the aniline used is pure aniline, and a 100 mg / L aniline ethanol solution is prepared.

[0011] The functional additives consist of a dispersant, a binder, and a stabilizer; the dispersant is sodium dodecylbenzenesulfonate, the binder is waterborne polyurethane, and the stabilizer is fumed silica.

[0012] The present invention also provides a method for preparing the above-mentioned graphene titanium dioxide photocatalytic antibacterial and antifungal agent, comprising the following steps:

[0013] S1. Synthesis of aniline-modified GO / N-TiO2 main catalytic component: Nitrogen-doped titanium dioxide powder, graphene oxide aqueous solution, and aniline ethanol solution were mixed and magnetically stirred for 5 h. The mixture was then transferred to a hydrothermal reactor and hydrothermally reacted at 160 °C for 5 h. After cooling and centrifugation, the mixture was washed successively with ethanol and deionized water and dried under vacuum at 60 °C to obtain the aniline-modified GO / N-TiO2 main catalytic component.

[0014] S2. Compound molding: The main catalytic component is mixed with dispersant, binder, stabilizer and antifungal synergist in proportion, and then stirred and ground at high speed to obtain graphene titanium dioxide photocatalytic antibacterial and antifungal agent.

[0015] Finally, the present invention also provides an application of the above-mentioned graphene titanium dioxide photocatalytic antibacterial and antifungal agent.

[0016] The graphene-titanium dioxide photocatalytic antibacterial and antifungal agent, its preparation method, and its application provided in the above technical solution have the following beneficial effects.

[0017] (1) The ternary synergistic catalytic system significantly improves visible light photocatalytic activity. Nitrogen-doped anatase TiO2 broadens the range of photocatalytic activity. Within the visible light response range, graphene oxide acts as a high-speed electron transport channel, rapidly transferring photogenerated electrons and suppressing electron-hole recombination, thus significantly improving photon efficiency. Compared to single N-TiO2 and binary GO / TiO2 materials, it can enhance the formaldehyde degradation rate and can be stably catalyzed under ordinary indoor weak visible light.

[0018] (2) π-π conjugation modification of aniline to achieve selective degradation of azo dyes. Aniline forms a π-π conjugated structure with graphene oxide to construct specific adsorption sites for organic pollutants, which can directionally capture azo dyes on the surface of water and textiles, solving the technical shortcomings of non-selectivity and incomplete dye degradation in traditional photocatalysis; at the same time, organic modification of aniline improves the interfacial bonding between powder and water-based resin and textile fibers.

[0019] (3) Photocatalysis synergistically inhibits bacteria with aniline, without organic antifungal agents, and has long-lasting stability. The photocatalytic reaction generates hydroxyl radicals and superoxide anion radicals, which destroy the bacterial cell membrane and the nucleic acid structure of mold spores. Aniline synergistically inhibits the metabolism and reproduction of microorganisms, without the need to add toxic organic antifungal agents; the powder is firmly loaded, resistant to water washing and high humidity environments, and has a long effective period of antifungal effect.

[0020] (4) Special compound additive system with excellent powder dispersion and processing compatibility. Sodium dodecylbenzene sulfonate eliminates the agglomeration problem of graphene and nano titanium dioxide; waterborne polyurethane adhesive is suitable for waterborne coatings and fabric impregnation processes; fumed silica improves the storage stability of powder, does not clump during long-term storage, and is compatible with various processing processes such as spraying, slurry blending, and fiber loading.

[0021] (5) The preparation process is simple and controllable, the raw materials are readily available, and it is suitable for large-scale mass production. The overall process only includes low-temperature hydrothermal reaction + room-temperature compounding and grinding. The reaction temperature is low and no large-scale high-temperature and high-pressure equipment is required. Nitrogen-doped titanium dioxide, graphene oxide and aniline are all commercially available raw materials, and the production cost is low. The catalytic performance decays only slightly after the product is recycled multiple times.

[0022] (6) Versatile for multiple scenarios, combining multiple functions such as air treatment, water purification, and material protection. When added to interior wall coatings, it can remove formaldehyde and prevent mold growth indoors; when used for textile finishing, it can remove residual azo dyes from printing and dyeing; when sprayed on wood panels, it can prevent wood from becoming moldy and degrade the volatile organic compounds in the panels; it can also be used for the treatment of printing and dyeing wastewater and the modification of air purification filters. It has a wide range of applications, and the reaction products do not cause secondary pollution, making it environmentally friendly. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this disclosure clearer, the technical solutions of this disclosure will be clearly and completely described below in conjunction with the embodiments of this disclosure. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this disclosure can be arbitrarily combined with each other.

[0024] Example 1

[0025] Raw material ratio (parts by mass): 90 parts anatase nitrogen-doped titanium dioxide, 0.1 parts graphene oxide, 3.5 parts aniline, 6 parts functional additives; aniline to graphene oxide mass ratio 35:1; functional additive components: 2 parts sodium dodecylbenzenesulfonate, 3 parts waterborne polyurethane, 1 part fumed silica.

[0026] Preparation of main catalytic components: (1) Prepare 0.1 mol / L aniline ethanol solution and 100 mg / L graphene oxide aqueous solution in advance; (2) Mix 90 parts of nitrogen-doped TiO2 powder, 0.1 parts of graphene oxide aqueous solution and 3.5 parts of aniline ethanol solution, and stir magnetically at room temperature for 5 h; (3) Transfer the mixture into a hydrothermal reactor and keep it at 160℃ for 5 h; (4) Cool naturally to room temperature, centrifuge at 8000 r / min to separate the solid, wash twice with ethanol and three times with deionized water to remove unreacted free aniline; (5) Dry in a vacuum oven at 60℃ for 8 h to obtain aniline-modified GO / N-TiO2 main catalytic powder.

[0027] Finished product compounding: Take the above main catalytic powder, add sodium dodecylbenzenesulfonate, waterborne polyurethane and fumed silica, stir and grind at high speed for 30 minutes, and after homogeneous dispersion, obtain graphene titanium dioxide photocatalytic antibacterial and antifungal agent powder.

[0028] Performance testing: After 2 hours of visible light irradiation, the formaldehyde degradation rate was 92.7%; the antibacterial performance against Escherichia coli and Staphylococcus aureus was ≥99.9%; the antifungal performance against Aspergillus niger, Penicillium, etc. was grade 0; and the degradation rate of acid red azo dye was 94.2% after 2 hours.

[0029] Example 2

[0030] Raw material ratio (parts by mass): 85 parts nitrogen-doped titanium dioxide, 0.08 parts graphene oxide, 2.4 parts aniline, 3 parts functional additives; aniline to graphene oxide mass ratio 30:1; functional additive components: 1 part sodium dodecylbenzenesulfonate, 1.5 parts waterborne polyurethane, 0.5 parts fumed silica.

[0031] The preparation of the main catalytic component and the compounding of the finished product are completely consistent with those in Example 1, with only the amount of each raw material added being adjusted.

[0032] Performance testing: Formaldehyde purification efficiency 86.3%, antibacterial performance against Escherichia coli and Staphylococcus aureus 99.6%; Acid red azo dye degradation rate of 88.1% in 2 hours, suitable for addition to low-cost interior wall coatings.

[0033] Example 3

[0034] Raw material ratio (parts by mass): 95 parts nitrogen-doped titanium dioxide, 0.12 parts graphene oxide, 6 parts aniline, 10 parts functional additives; aniline to graphene oxide mass ratio 50:1; functional additive components: 3 parts sodium dodecylbenzenesulfonate, 5 parts waterborne polyurethane, 2 parts fumed silica.

[0035] The preparation of the main catalytic component and the compounding of the finished product are completely consistent with those in Example 1, with only the amount of each raw material added being adjusted.

[0036] Performance testing: Formaldehyde degradation rate under visible light is 95.1%; Acid red azo dye degradation rate is 96.8% after 2 hours; Powder adhesion is strong and water washability is excellent, making it suitable for textile and wood product impregnation loading scenarios.

[0037] Comparative Example 1

[0038] Only 90 parts of nitrogen-doped titanium dioxide were used, without the addition of graphene oxide or aniline. The remaining functional additives and finished product formulations were consistent with those in Example 1.

[0039] Performance testing: The formaldehyde degradation rate under visible light was only 37.2%, and it had no selective adsorption and degradation ability for azo dyes. After 7 days of cultivation, a large number of molds grew on the surface of the sample, and the bacterial inhibition rate was less than 70%.

[0040] Comparative Example 2

[0041] Raw material ratio (parts by weight): 90 parts nitrogen-doped titanium dioxide, 0.1 parts graphene oxide, no aniline added, and the remaining functional additives and finished product formulation are consistent with those in Example 1.

[0042] Performance testing: Formaldehyde degradation rate under visible light is 71.5%, no selective degradation effect of azo dyes, and anti-mildew performance is significantly reduced under long-term high humidity environment.

[0043] The above embodiments are only used to illustrate the technical solutions of this disclosure, and are not intended to limit it. Although this disclosure has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this disclosure.

[0044] The above-described contents can be implemented individually or in various combinations, and all such variations are within the scope of this disclosure.

Claims

1. A graphene-titanium dioxide photocatalytic antibacterial and antifungal agent, characterized in that, It includes a main catalytic component and functional additives; the main catalytic component is a functionalized graphene oxide titanium dioxide composite material, wherein the functionalized graphene oxide titanium dioxide is based on nitrogen-doped titanium dioxide, and graphene oxide and aniline are sequentially loaded on the surface of titanium dioxide.

2. The graphene oxide-titanium dioxide photocatalytic antibacterial and antifungal agent according to claim 1, characterized in that, The proportions of each component by mass are as follows: 85-95 parts nitrogen-doped titanium dioxide, 0.08-0.12 parts graphene oxide, 2.4-6 parts aniline, and 3-10 parts functional additives; wherein the mass ratio of aniline to graphene oxide is 30:1-50:

1.

3. The graphene oxide-titanium dioxide photocatalytic antibacterial and antifungal agent according to claim 2, characterized in that, The nitrogen-doped titanium dioxide is anatase type with a particle size of 5-30 nm; the graphene oxide has a particle size of 10-300 nm, ≤5 layers, a purity of 99.5%, and a specific surface area of ​​500 m² / g.

4. The graphene oxide-titanium dioxide photocatalytic antibacterial and antifungal agent according to claim 1, characterized in that, The aniline used is pure aniline, and a 100 mg / L aniline ethanol solution is prepared.

5. The graphene oxide-titanium dioxide photocatalytic antibacterial and antifungal agent according to claim 1, characterized in that, The functional additives include dispersants, binders, and stabilizers; the dispersant is sodium dodecylbenzenesulfonate, the binder is waterborne polyurethane, and the stabilizer is fumed silica.

6. A method for preparing the graphene oxide-titanium dioxide photocatalytic antibacterial and antifungal agent according to any one of claims 1-5, characterized in that, The process includes the following steps: (1) Synthesis of aniline-modified GO / N-TiO2 main catalytic component: Nitrogen-doped titanium dioxide powder, graphene oxide aqueous solution and aniline ethanol solution are mixed, magnetically stirred for 5 hours, transferred to a hydrothermal reactor, hydrothermally reacted at 160°C for 5 hours, cooled and centrifuged, washed with ethanol and deionized water in sequence, and vacuum dried at 60°C to obtain aniline-modified GO / N-TiO2 main catalytic component; (2) Compound molding: The main catalytic component is mixed with dispersant, binder, stabilizer and antifungal synergist according to the ratio, and stirred and ground at high speed to obtain graphene titanium dioxide photocatalytic antibacterial and antifungal agent.

7. The preparation method according to claim 6, characterized in that, In step (1), the concentration of aniline ethanol solution is 0.1 mol / L, and the mass ratio of aniline to graphene oxide is controlled at 30:1-50:

1.

8. The application of the graphene-titanium dioxide photocatalytic antibacterial and antifungal agent according to any one of claims 1-5, characterized in that, The antibacterial and antifungal agent is applied in the fields of indoor air purification, wall coatings, wood products, textiles, and aquatic environments for antibacterial, formaldehyde removal, degradation of organic pollutants, and antifungal properties; it can exert a long-lasting photocatalytic effect under ultraviolet and visible light conditions.

9. The application according to claim 8, characterized in that, When used, the antibacterial and antifungal agent can be directly powdered, added to coatings / slurries, or loaded onto fiber substrates. Under light conditions, it can efficiently degrade organic pollutants such as formaldehyde, while inhibiting the growth of bacteria and mold. It also has selective degradation capabilities for azo pollutants (mainly azo dyes).