A TiO2 / Bi2S3 / PCs composite photocatalyst film and its preparation method and application
The TiO2/Bi2S3/PCs composite photocatalyst film solves the problem of narrow photoresponse range of TiO2 photocatalyst, achieves efficient degradation of antibiotic wastewater, and has good stability and wide applicability.
Patent Information
- Application Number
- CN202310907646.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-07-21
- Publication Date
- 2025-09-05
- Estimated Expiration
- 2043-07-21
AI Technical Summary
Existing TiO2 photocatalysts have a wide band gap, narrow light response range, and low quantum efficiency, which limits their application in antibiotic wastewater treatment, and traditional methods are difficult to effectively degrade antibiotic pollution.
A TiO2/Bi2S3/PCs composite photocatalyst film was used. By uniformly dispersing TiO2 nanoparticles on the Bi2S3 surface and compounding it with a photonic crystal layer prepared from SiO2 microspheres, the light absorption range was broadened and the photocatalytic activity was improved.
It achieves a high degradation rate of antibiotic wastewater (over 90%), has good photocatalytic stability and wide applicability, and is suitable for the treatment of different types of antibiotic wastewater.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of antibiotic wastewater treatment and photocatalytic materials, and specifically relates to a TiO2 / Bi2S3 / PCs composite photocatalyst film, a preparation method thereof, and an application thereof. Background Art
[0002] In recent years, the widespread use of antibiotics and their resistance to degradation have led to an increasing incidence of antibiotic residues in water and soil. These residual antibiotics pose a significant threat to human survival and health. Therefore, an effective method to eliminate antibiotic pollution is necessary.
[0003] Compared with traditional methods such as biological treatment and physical adsorption, photocatalytic treatment technology not only has the advantages of low cost and high efficiency, but is also green and environmentally friendly.
[0004] Among them, TiO2 has been used in the treatment of organic wastewater due to its advantages such as corrosion resistance, low cost and non-toxicity. However, due to the wide band gap, narrow photoresponse range and low quantum efficiency of TiO2, its industrialization and application are restricted. Compounding with narrow-bandgap semiconductors can broaden the light absorption range and is an effective way to improve the catalytic activity of TiO2. However, improving the photocatalytic performance of semiconductor materials by simply broadening the light absorption range is not enough. Therefore, there is an urgent need to find a simple method to obtain TiO2 photocatalysts with excellent photocatalytic performance to eliminate antibiotic pollution. Summary of the Invention
[0005] The purpose of the present invention is to provide a TiO2 / Bi2S3 / PCs composite photocatalyst film, a preparation method and application thereof. When the composite photocatalyst film material is used to degrade antibiotics, the degradation rate can be as high as over 90%. At the same time, it has good photocatalytic stability, can be recycled multiple times, and is easy to recycle. It has a better degradation effect on different types of antibiotic wastewater and has a wide applicability.
[0006] To achieve the above object, the present invention adopts the following technical solutions:
[0007] Provided is a TiO2 / Bi2S3 / PCs composite photocatalyst film, which sequentially comprises a photonic crystal (PCs) layer and a TiO2 / Bi2S3 composite material layer; wherein:
[0008] In the TiO2 / Bi2S3 composite material layer, the mass ratio of TiO2 to Bi2S3 is 0.2-1.2:1; the TiO2 is a mixed crystal of anatase and rutile phases; and the TiO2 nanoparticles are evenly distributed on the micron-flower-like surface of the Bi2S3.
[0009] The photonic crystal layer is a photonic crystal prepared from SiO2 microspheres, wherein the particle size of the SiO2 microspheres is 200-250 nm.
[0010] According to the above scheme, the thickness of the photonic crystal (PCs) layer is 2 to 5 μm; the thickness of the TiO2 / Bi2S3 composite material layer is 2 to 5 μm.
[0011] According to the above solution, the photonic band gap of the photonic crystal in the photonic crystal layer is 420 to 550 nm, preferably 430 to 500 nm.
[0012] According to the above scheme, the mass ratio of TiO2 and Bi2S3 is 0.6 to 1:1.
[0013] According to the above scheme, the composite photocatalyst film is prepared by adding tetrabutyl titanate and glacial acetic acid to water, mixing the mixture, then dropwise adding HNO3 and refluxing in a water bath to obtain a TiO2 sol, adding Bi2S3 powder to the TiO2 sol and performing a hydrothermal reaction at 150-220°C, then sequentially adding an ethanol-water mixed solvent and polyethylene glycol (PEG 4000) to obtain a TiO2 / Bi2S3 slurry, and finally coating the slurry on a photonic crystal film prepared from SiO2 microspheres and calcining the slurry. Preferably, the hydrothermal reaction time is 6-12 hours.
[0014] A method for preparing the composite photocatalyst thin film is provided, comprising the following steps:
[0015] 1) Tetrabutyl titanate and glacial acetic acid are added to water and mixed, followed by dropwise addition of HNO3 and reflux in a water bath to obtain a TiO2 sol, Bi2S3 powder is added to the TiO2 sol and subjected to a hydrothermal reaction at 150-220°C, and an ethanol-water mixed solvent and polyethylene glycol (PEG 4000) are sequentially added to the hydrothermal product to obtain a TiO2 / Bi2S3 slurry;
[0016] 2) SiO2 microspheres are used as raw materials to prepare a photonic crystal film, and then the TiO2 / Bi2S3 slurry obtained in step 1) is coated on the obtained photonic crystal film, and then naturally dried and calcined to obtain a TiO2 / Bi2S3 / PCs composite photocatalyst film.
[0017] According to the above scheme, in step 1), the preparation of Bi2S3 powder is specifically as follows: bismuth nitrate pentahydrate is used as a bismuth source, thiourea is used as a sulfur source, added to ethylene glycol, ultrasonically stirred and then hydrothermally reacted, and after the reaction is completed, the product is dried to obtain Bi2S3 powder.
[0018] Preferably, the mass ratio of bismuth nitrate pentahydrate to thiourea is 15-30:7-16.
[0019] Preferably, the hydrothermal reaction conditions are: hydrothermal reaction at 100-180° C. for 8-12 hours.
[0020] According to the above scheme, in step 1), the volume ratio of tetrabutyl titanate, glacial acetic acid, water and nitric acid is 1:1-2:80-120:0.1-0.5; and the concentration of nitric acid is 30%-60%.
[0021] According to the above scheme, the mass ratio of tetrabutyl titanate, calculated as TiO2, to Bi2S3 is 0.2 to 1.2:1.
[0022] According to the above scheme, in step 1), the water bath reflux time is 30 to 200 minutes; preferably, the reflux temperature is 60 to 100°C.
[0023] According to the above scheme, in step 1), HNO3 is added dropwise and then refluxed in a water bath until the solution becomes a light blue colloid, and then filtered with a filter membrane to remove non-colloidal precipitated particles to obtain TiO2 sol; wherein the filter membrane size is 0.1-0.5 μm.
[0024] According to the above scheme, in step 1), the hydrothermal reaction temperature is 180-210°C.
[0025] According to the above scheme, in step 1), the hydrothermal reaction time is 6 to 12 hours.
[0026] According to the above scheme, in step 1), the mass percentage concentration of TiO2 / Bi2S3 in the ethanol-water mixed solvent is 8-15%; the amount of polyethylene glycol added accounts for 30-50% of the mass of TiO2 / Bi2S3.
[0027] According to the above scheme, in step 1), the volume ratio of ethanol to water in the ethanol-water mixed solvent is 3 to 0.5:1.
[0028] According to the above scheme, in step 2), the calcination temperature is 200-600° C., and the time is 30-150 min; preferably, the heating rate is 2-10° C. / min.
[0029] According to the above scheme, in step 2), the specific steps of preparing the photonic crystal film using SiO2 microspheres as raw materials are as follows: dispersing the SiO2 microspheres in an ethanol-water mixed solvent to obtain a SiO2 suspension; immersing a glass slide in the suspension at a certain angle so that only one side is dipped in the suspension, then slowly lifting the glass slide and placing it on the table with the side dipped in the suspension facing up, waiting for it to dry naturally and then calcining it to obtain a PCs film.
[0030] Preferably, the calcination temperature is 200-500° C., and the calcination time is 30-100 min.
[0031] Preferably, in the ethanol-water mixed solvent, the volume ratio of ethanol to water is 3 to 0.5:1.
[0032] According to the above scheme, in step 2), coating is carried out on a coating machine, wherein the speed of the low-speed stage is set to 10-1000 rpm and the time is 1-30 s; the speed of the high-speed stage is set to 1000-3000 rpm and the time is 10-120 s.
[0033] According to the above scheme, in step 2), the photonic band gap of the PCs obtained is 420nm to 550nm, preferably 430 to 500nm.
[0034] Provided is an application of the TiO2 / Bi2S3 / PCs composite photocatalyst in degrading antibiotics in wastewater.
[0035] According to the above scheme, the antibiotic is at least one of tetracycline, ciprofloxacin, sulfadiazine or ofloxacin.
[0036] According to the above scheme, the application is: placing the TiO2 / Bi2S3 / PCs composite photocatalyst film in an antibiotic solution, stirring in the dark until adsorption-desorption equilibrium is reached, and then irradiating with a xenon lamp light source.
[0037] Preferably, the light-proof stirring time is 20 to 60 minutes.
[0038] Preferably, the illumination time is 0 to 140 minutes.
[0039] Compared with the prior art, the present invention has the following beneficial effects:
[0040] 1. The TiO2 / Bi2S3 / PCs composite photocatalyst film material provided by the present invention comprises a PCs layer and a TiO2 / Bi2S3 composite material layer. The titanium dioxide is a mixed crystal of anatase and rutile phases, which exhibits stronger photocatalytic performance than single crystals. TiO2 particles are evenly dispersed on the surface of the micron-sized flower-shaped Bi2S3. The flower-shaped Bi2S3 provides a larger specific surface area, which, when combined with the TiO2, effectively expands the visible light absorption range of the TiO2 photocatalyst. Simultaneously, SiO2 microspheres of appropriate particle size are selected to produce photonic crystals with a photonic band gap that matches the electronic band gap of TiO2 / Bi2S3, significantly enhancing the activity of the photocatalyst. The resulting composite photocatalyst film material exhibits a wide photoresponse in the visible light range and high light utilization efficiency. When used to degrade antibiotics, the degradation rate can reach over 90%. It also exhibits good photocatalytic stability, can be recycled multiple times, and is easily recyclable. It exhibits excellent degradation effects on different types of antibiotic wastewater, has broad applicability, and has broad application prospects.
[0041] 2. The present invention provides a method for preparing a composite photocatalyst film, in which mixed crystal TiO2 is uniformly dispersed on the surface of micron-flower-shaped Bi2S3 through a simple hydrothermal reaction; and silica photonic crystals PCs and TiO2 / Bi2S3 composite materials are compounded through a simple coating method. The preparation method is simple, the conditions are mild and controllable, and it is suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS
[0042] Figure 1 This is the SEM image of TiO2 / Bi2S3 obtained in Example 1.
[0043] Figure 2 These are the X-ray diffraction patterns of the TiO2 / Bi2S3 photocatalytic films obtained in Example 1, and the A-TiO2 / Bi2S3 and R-TiO2 / Bi2S3 photocatalytic films obtained in Comparative Examples 1 to 2.
[0044] Figure 3 The effect diagram of the composite film photocatalytic degradation of tetracycline obtained in Example 1 and Comparative Examples 1 and 2 is shown.
[0045] Figure 4 This is the SEM side view of TiO2 / Bi2S3 / PCs (458) obtained in Example 2.
[0046] Figure 5 This is a diagram showing the effect of photocatalytic degradation of tetracycline by the composite films obtained in Example 2 and Comparative Example 3.
[0047] Figure 6 The diagram shows the effect of photocatalytic degradation of tetracycline by the composite films obtained in Example 2 and Comparative Examples 4 to 6.
[0048] Figure 7 This is the experimental diagram of the photocatalytic degradation of tetracycline by TiO2 / Bi2S3 / PCs(458) composite film in Example 3. DETAILED DESCRIPTION
[0049] In order to better understand the present invention, the content of the present invention is further illustrated below in conjunction with examples, but the present invention is not limited to the following examples.
[0050] To evaluate the photocatalytic activity of the photocatalyst prepared in the present invention, a TiO2 / Bi2S3 / PCs composite photocatalyst film was placed on a support and a tetracycline hydrochloride solution (30 mg / L) was added to a reactor. The solution was stirred in the dark for 30 minutes until adsorption-desorption equilibrium was reached. The solution was then illuminated with a xenon lamp. Every 20 minutes, 3 ml of the irradiated solution was sampled and measured using a UV-visible spectrophotometer. The absorbance of the characteristic peak at 357 nm was recorded. Finally, the degradation rate of tetracycline was calculated according to the Lambert-Beer law.
[0051] All reagents used in the present invention were of analytical grade, and antibiotics such as tetracycline, ciprofloxacin, sulfadiazine, and ofloxacin were purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. Other reagents were purchased from Sinopharm Chemical Reagent Co., Ltd.
[0052] Example 1
[0053] A method for preparing a TiO2 / Bi2S3 composite film photocatalyst is provided, comprising the following steps:
[0054] 1) Using bismuth nitrate pentahydrate as the bismuth source and thiourea as the sulfur source, 150 mg of bismuth nitrate pentahydrate and 75 mg of thiourea were placed in 40 ml of ethylene glycol, and the mixture was subjected to ultrasonic stirring and hydrothermal reaction at 180°C for 8 h. After the reaction was completed, the mixture was centrifuged, washed, and dried to obtain Bi2S3 powder for later use;
[0055] 2) Add 3 ml of tetrabutyl titanate and 5 ml of glacial acetic acid solution to 320 ml of deionized water and stir. Then add 1.2 ml of 30 wt% HNO3 dropwise. Reflux in a water bath for 70 min until the solution becomes a light blue colloid. Filter through a 0.1 μm filter membrane and collect the filtrate to obtain 300 ml of TiO2 sol.
[0056] 3) 80 mg of the prepared Bi2S3 powder was added to 30 ml of TiO2 sol, mixed thoroughly, and then transferred to a hydrothermal reactor for reaction at 200°C for 8 h. After the reaction, the TiO2 / Bi2S3 solid product was centrifuged and washed. A 2:1 ethanol-water mixture was then added to prepare a solution containing 10 wt% of the solid product. Polyethylene glycol (PEG4000) was then added (40 wt% of the solid product content) and stirred at low speed until fully dissolved, forming a TiO2 / Bi2S3 slurry of suitable consistency.
[0057] 4) A clean glass slide was then placed on the platform of a spinner. The TiO2 / Bi2S3 slurry was then coated onto the clean glass slide. The slide was rotated at a low speed of 500 rpm for 6 seconds and a high speed of 1500 rpm for 50 seconds. After drying naturally, the TiO2 film was calcined in a muffle furnace at 300°C for 30 minutes to obtain a TiO2 / Bi2S3 photocatalyst film with a thickness of 2.26 μm, which was designated as TiO2 / Bi2S3.
[0058] Figure 1 This is a scanning transmission electron micrograph of the TiO2 / Bi2S3 photocatalyst prepared in the present invention, showing that TiO2 nanoparticles are evenly dispersed on the surface of the micron-flower-like Bi2S3.
[0059] Comparative Example 1
[0060] Provided is a method for preparing an A-TiO2 / Bi2S3 composite film photocatalyst, comprising the following steps:
[0061] 1) Using bismuth nitrate pentahydrate as the bismuth source and thiourea as the sulfur source, 150 mg of bismuth nitrate pentahydrate and 75 mg of thiourea were placed in 40 ml of ethylene glycol. After ultrasonic stirring, the mixture was hydrothermally reacted at 180°C for 8 h. After the reaction was completed, the mixture was centrifuged, washed, and dried to obtain Bi2S3 powder for later use.
[0062] 2) Add 3 ml of tetrabutyl titanate and 5 ml of glacial acetic acid solution to 320 ml of deionized water and stir. Then, add 1.2 ml of 30 wt% HNO3 dropwise and reflux in a water bath for 70 min until the solution turns into a light blue colloid. Filter with a membrane and collect the filtrate to obtain 300 ml of TiO2 sol.
[0063] 3) 80 mg of the prepared Bi2S3 powder was added to 30 ml of TiO2 sol, mixed thoroughly, and transferred to a hydrothermal reactor. The mixture was reacted at 140°C for 8 h. After the reaction, the TiO2 / Bi2S3 solid product was centrifuged and washed. A 2:1 ethanol-water mixture was then added to prepare a solution containing 10 wt% of the solid product. Polyethylene glycol (PEG4000) was then added (40 wt% of the solid product content) and stirred at low speed until fully dissolved, forming a TiO2 / Bi2S3 slurry of suitable consistency.
[0064] 4) After placing a clean glass slide on the platform of a spin coater, apply the TiO2 / Bi2S3 slurry to the clean glass slide and spin at a low speed of 500 rpm for 6 seconds and a high speed of 1500 rpm for 50 seconds. After drying naturally, the TiO2 film is calcined in a muffle furnace at 300°C for 30 minutes to obtain a TiO2 / Bi2S3 photocatalyst film, designated A-TiO2 / Bi2S3.
[0065] Comparative Example 2
[0066] Provided is a method for preparing an R-TiO2 / Bi2S3 composite film photocatalyst, comprising the following steps:
[0067] 1) Using bismuth nitrate pentahydrate as the bismuth source and thiourea as the sulfur source, 150 mg of bismuth nitrate pentahydrate and 75 mg of thiourea were placed in 40 ml of ethylene glycol. After ultrasonic stirring, the mixture was hydrothermally reacted at 180°C for 8 h. After the reaction was completed, the mixture was centrifuged, washed, and dried to obtain Bi2S3 powder for later use.
[0068] 2) Add 3 ml of tetrabutyl titanate and 5 ml of glacial acetic acid solution to 320 ml of deionized water and stir. Then, add 1.2 ml of 30 wt% HNO3 dropwise and reflux in a water bath for 70 min until the solution turns into a light blue colloid. Filter with a membrane and collect the filtrate to obtain 300 ml of TiO2 sol.
[0069] 3) 80 mg of the prepared Bi2S3 powder was added to 30 ml of TiO2 sol, mixed thoroughly, and transferred to a hydrothermal reactor. The mixture was reacted at 230°C for 8 h. After the reaction, the TiO2 / Bi2S3 solid product was centrifuged and washed. A 2:1 ethanol-water mixture was then added to prepare a solution containing 10 wt% of the solid product. Polyethylene glycol (PEG4000) was then added (40 wt% of the solid product content) and stirred at low speed until fully dissolved, forming a TiO2 / Bi2S3 slurry of suitable consistency.
[0070] 4) After placing a clean glass slide on the platform of a spin coater, apply the TiO2 / Bi2S3 slurry to the clean glass slide and spin at a low speed of 500 rpm for 6 seconds and a high speed of 1500 rpm for 50 seconds. After drying naturally, the TiO2 film is calcined in a muffle furnace at 300°C for 30 minutes to obtain a TiO2 / Bi2S3 photocatalyst film, designated R-TiO2 / Bi2S3.
[0071] Figure 2 X-ray diffraction patterns of the TiO2 / Bi2S3, A-TiO2 / Bi2S3, and R-TiO2 / Bi2S3 photocatalysts prepared in Example 1 and Comparative Examples 1 and 2. The figures show that the TiO2 crystal form in Example 1 is a mixed crystal of anatase and rutile phases; the TiO2 crystal form in Comparative Example 1 is anatase; and the TiO2 crystal form in Comparative Example 2 is rutile.
[0072] Figure 3 The following graphs show the photocatalytic degradation of tetracycline using the composite films obtained in Example 1 and Comparative Examples 1 and 2. As shown in the graph, the degradation rate of tetracycline hydrochloride by the catalyst obtained in Example 1 was 56.57% within 140 minutes; the degradation rate of tetracycline hydrochloride by the catalyst obtained in Comparative Example 1 was 50.73% within 140 minutes; and the degradation rate of tetracycline hydrochloride by the catalyst obtained in Comparative Example 2 was 41.61% within 140 minutes. The performance of the TiO2 / Bi2S3 material obtained in Example 1 was significantly higher than that of the A-TiO2 / Bi2S3 and R-TiO2 / Bi2S3 obtained in Comparative Examples 1 and 2, indicating that the photocatalytic performance is optimal when the TiO2 crystal form is a mixed crystal and is composited with Bi2S3.
[0073] Example 2
[0074] Preparation of TiO2 / Bi2S3 / PCs(458) and degradation of tetracycline hydrochloride antibiotics.
[0075] (1) Preparation of TiO2 / Bi2S3 slurry:
[0076] Using bismuth nitrate pentahydrate as the bismuth source and thiourea as the sulfur source, 150 mg of bismuth nitrate pentahydrate and 75 mg of thiourea were placed in a beaker containing 40 ml of ethylene glycol. Ultrasonic stirring was performed and the mixture was transferred to a hydrothermal reactor. The mixture was reacted at 180°C for 8 hours. After completion of the reaction, the mixture was centrifuged, washed, and dried to obtain Bi2S3 powder for later use. 3 ml of tetrabutyl titanate and 5 ml of glacial acetic acid solution were added to 320 ml of deionized water and stirred. 1.2 ml of 30 wt% HNO3 was then added dropwise. The mixture was refluxed in a water bath for 70 minutes until the solution turned into a light blue colloid. The solution was filtered through a filter membrane to remove uncolloidated precipitated particles. The filtrate was collected to obtain 300 ml of TiO2 sol. 80 mg of the prepared Bi2S3 powder was added to the 30 ml of TiO2 sol, mixed thoroughly, and transferred to a hydrothermal reactor. The reaction was continued at 200°C for 8 hours. After the reaction is completed, the TiO2 / Bi2S3 solid product is obtained by centrifugation and washing, and then an ethanol-water mixed solvent with a volume ratio of 2:1 is added to prepare a solution with a solid product content of 10 wt%, and then polyethylene glycol (PEG 4000) (the amount added is 40 wt% of the solid product content) is added, and stirred at a low speed until it is fully dissolved to form a TiO2 / Bi2S3 slurry with suitable consistency.
[0077] (2) Preparation of TiO2 / Bi2S3 / PCs(458) composite photocatalyst:
[0078] SiO2 microspheres with a particle size of 230 nm were dispersed in a 2:1 volume ratio of ethanol-water mixed solvent to obtain a SiO2 suspension. A hydrophilic glass slide was immersed in the suspension at a certain angle so that only one side was dipped in the suspension. The glass slide was then slowly lifted and placed on a table with the surface dipped in the suspension facing up. After it was allowed to dry naturally, it was transferred to a muffle furnace and calcined at 400°C for 120 minutes to obtain a PCs (458) film with a thickness of 3.24 μm for use. 458 represents the theoretically calculated photonic band gap of PCs, representing a photonic band gap of 458 nm. The same applies to other films. The prepared PCs (458) was placed horizontally on the platform of the slurry spreader, and then the slurry in step (1) was coated on the PCs, rotated at a low speed of 500 rpm for 6 seconds and at a high speed of 1500 rpm for 50 seconds. After natural drying, the composite film was placed in a muffle furnace and calcined at 300 ° C for 30 minutes to obtain a TiO2 / Bi2S3 / PCs (458) composite photocatalyst film.
[0079] (3) The TiO2 / Bi2S3 / PCs(458) film obtained in (2) was subjected to a photocatalytic degradation test, and it was found that the degradation rate of tetracycline hydrochloride antibiotics by the photocatalyst reached 90.65% in 140 minutes.
[0080] Figure 3This is a side SEM image of the TiO2 / Bi2S3 / PCs(458) film prepared in the present invention. The image clearly shows that PC(458) is a three-dimensional face-centered cubic structure composed of uniformly sized, flat microspheres arranged and tightly bound together. The TiO2 / Bi2S3 / PCs(458) composite film is composed of distinct TiO2 / Bi2S3 layers and PC(458) layers.
[0081] Comparative Example 3
[0082] Preparation of TiO2 / Bi2S3 / dis-PCs composite photocatalyst and degradation of tetracycline hydrochloride antibiotics.
[0083] (1) Preparation of TiO2 / Bi2S3: Same as step (1) in Example 2 above.
[0084] (2) Preparation of TiO2 / Bi2S3 / dis-PCs composite photocatalyst:
[0085] SiO2 microspheres with particle sizes of 180nm, 230nm, and 280nm were mixed and dispersed in a mixed solvent of ethanol and water with a volume ratio of 2:1 to obtain a SiO2 suspension. A glass slide was then immersed in the suspension and placed in a vacuum drying oven at 60°C. After the solution was completely evaporated, the glass slide was removed and transferred to a muffle furnace and calcined at 400°C for 120 minutes to obtain disordered PCs (denoted as dis-PCs) for later use. The prepared dis-PCs were placed horizontally on the platform of a homogenizer, and the slurry in step (1) was then coated on the dis-PCs. The film was rotated at a low speed of 500rpm for 6s and a high speed of 1500rpm for 50s. After natural drying, the composite film was placed in a muffle furnace and calcined at 300°C for 30 minutes to obtain a TiO2 / Bi2S3 / dis-PCs composite photocatalyst film.
[0086] (3) The TiO2 / Bi2S3 / dis-PCs prepared in step (2) was subjected to a photocatalytic degradation test, and the degradation rate of tetracycline hydrochloride antibiotics by the photocatalyst was measured to be 70.66% within 140 min.
[0087] Figure 4 The results of the photocatalytic degradation of tetracycline by the composite films obtained in Example 2 and Comparative Example 3 are shown. The results show that the ordered assembled PCs can make better use of sunlight than the disordered dis-PCs, thereby effectively improving the photocatalytic activity of TiO2 / Bi2S3.
[0088] Comparative Example 4
[0089] Preparation of TiO2 / Bi2S3 / PCs(397) composite photocatalyst and degradation of tetracycline hydrochloride antibiotics.
[0090] (1) Preparation of TiO2 / Bi2S3: Same as step (1) in Example 2 above.
[0091] (2) Preparation of TiO2 / Bi2S3 / PCs(397) composite photocatalyst:
[0092] SiO2 microspheres with a particle size of 180 nm were dispersed in an ethanol-water mixed solvent to obtain a SiO2 suspension. Then, a photonic crystal PCs (397) was prepared according to step (2) of Example 2, and a TiO2 / Bi2S3 / PCs (397) composite photocatalyst film was prepared by the spin coating method in step (2) of Example 2.
[0093] (3) The TiO2 / Bi2S3 / PCs (397) prepared in step (2) was subjected to a photocatalytic degradation test, and the degradation rate of the tetracycline hydrochloride antibiotic by the photocatalyst was measured to be 65.78% within 140 min.
[0094] Comparative Example 5
[0095] Preparation of TiO2 / Bi2S3 / PCs(616) composite photocatalyst and degradation of tetracycline hydrochloride antibiotics.
[0096] (1) Preparation of TiO2 / Bi2S3: Same as step (1) in Example 2 above.
[0097] (2) Preparation of TiO2 / Bi2S3 / PCs(616) composite photocatalyst:
[0098] SiO2 microspheres with a particle size of 280 nm were dispersed in an ethanol-water mixed solvent to obtain a SiO2 suspension. Then, a photonic crystal PCs (616) was prepared according to step (2) of Example 2, and then a TiO2 / Bi2S3 / PCs (616) composite photocatalyst thin film was obtained by spin coating in step (2) of Example 2.
[0099] (3) The TiO2 / Bi2S3 / PCs (616) prepared in step (2) was subjected to a photocatalytic degradation test, and the degradation rate of the tetracycline hydrochloride antibiotic by the photocatalyst was measured to be 78.78% within 140 min.
[0100] Comparative Example 6
[0101] Preparation of TiO2 photocatalyst film and degradation of tetracycline hydrochloride antibiotics.
[0102] (1) Preparation of TiO2 film photocatalyst:
[0103] 3 ml of tetrabutyl titanate and 5 ml of glacial acetic acid solution were added to 320 ml of deionized water and stirred. 1.2 ml of 30 wt% HNO₃ was then added dropwise. The mixture was refluxed in a water bath for 70 minutes until the solution turned into a light blue colloid. The solution was then filtered through a filter membrane to remove any uncolloidalized precipitated particles. The filtrate was collected to obtain a TiO₂ sol. This sol was then transferred to a hydrothermal reactor and reacted at 230°C for 8 hours. After the reaction, the TiO₂ solid product was washed by centrifugation. A 2:1 ethanol-water mixture was then added to prepare a 10 wt% solid product solution. Polyethylene glycol (PEG 4000) was then added (40 wt% of the solid product content) and stirred at low speed until fully dissolved, forming a TiO₂ slurry of suitable consistency. A clean glass slide was placed on the platform of a spin coater and TiO₂ coated onto the clean glass slide. The spin coater was rotated at a low speed of 500 rpm for 6 seconds and a high speed of 1500 rpm for 50 seconds. After it is naturally dried, the TiO2 film is placed in a muffle furnace and calcined at 300°C for 30 minutes to obtain a TiO2 photocatalyst film.
[0104] (2) The TiO2 film in (1) was subjected to a photocatalytic degradation test, and it was found that the degradation rate of tetracycline hydrochloride antibiotics by the photocatalyst was only 26.57% within 140 minutes.
[0105] Figure 5 The effect diagram of tetracycline degradation by the photocatalytic films obtained in Examples 1 to 2 and Comparative Examples 4 to 6 is shown. The performance of Example 2 is better than that of Comparative Examples 4-5. The reason is that the difference between Example 2 and Comparative Examples 4 to 5 is that the particle size of SiO2 microspheres is different. The different particle sizes of SiO2 microspheres will form photonic crystals with different band gaps. When TiO2 / Bi2S3 is compounded with photonic crystals with different photonic band gaps, different photocatalytic activities are exhibited. The possible reason for this phenomenon is that when the photonic band gap of the photonic crystal matches the electronic band gap of the semiconductor catalyst, the activity of the photocatalyst can be greatly improved.
[0106] Example 3
[0107] The TiO2 / Bi2S3 / PCs (458) composite photocatalyst film used in Example 2 was washed three times with anhydrous ethanol and deionized water to obtain a recovered catalyst film. The process of step (3) in Example 2 was repeated.
[0108] Figure 6 The experimental cycle diagram of the obtained TiO2 / Bi2S3 / PCs(458) composite film for the photocatalytic degradation of tetracycline is shown. The experimental results show that after four cycles, the efficiency of the TiO2 / Bi2S3 / PCs(458) composite photocatalyst film in degrading tetracycline can still be maintained above 85%, indicating that the photocatalyst synthesized by the present invention has good photocatalytic stability.
[0109] The above embodiments are only specific embodiments of the present invention, and the protection of the present invention is not limited thereto. It is pointed out here that improvements and modifications made by those skilled in the art based on the above invention and ideas should also be considered as the scope of protection of the present invention.
Claims
1. A TiO2 / Bi2S3 / PCs composite photocatalyst film, characterized in that: It includes a photonic crystal layer and a TiO2 / Bi2S3 composite material layer in sequence; wherein: In the TiO2 / Bi2S3 composite material layer, the mass ratio of TiO2 to Bi2S3 is 0.2-1.2:1; the TiO2 is a mixed crystal of anatase and rutile phases; and the TiO2 particles are evenly distributed on the micron-flower-like surface of the Bi2S3. The photonic crystal layer is prepared from SiO2 microspheres, and the particle size of the SiO2 microspheres is 200-250nm.
2. The composite photocatalyst thin film according to claim 1, characterized in that: The thickness of the photonic crystal layer is 2~5μm; the thickness of the TiO2 / Bi2S3 composite material layer is 2~5μm.
3. The composite photocatalyst thin film according to claim 1, characterized in that The photocatalyst film is prepared by adding tetrabutyl titanate and glacial acetic acid into water, mixing the mixture, then dropwise adding HNO3 and refluxing in a water bath to obtain a TiO2 sol, adding Bi2S3 powder into the TiO2 sol to carry out a hydrothermal reaction at 150-220°C, then sequentially adding an ethanol-water mixed solvent and polyethylene glycol to obtain a TiO2 / Bi2S3 slurry, and finally coating the slurry on a photonic crystal film prepared from SiO2 microspheres and calcining the slurry.
4. A method for preparing the composite photocatalyst thin film according to claim 1, characterized in that: The following steps are involved: 1) Tetrabutyl titanate and glacial acetic acid were added to water and mixed. HNO3 was then added dropwise and refluxed in a water bath to obtain a TiO2 sol. Bi2S3 powder was added to the TiO2 sol and subjected to a hydrothermal reaction at 150-220°C. An ethanol-water mixed solvent and polyethylene glycol were sequentially added to the hydrothermal product to obtain a TiO2 / Bi2S3 slurry. 2) A photonic crystal film is prepared using SiO2 microspheres as a raw material, and then the TiO2 / Bi2S3 slurry obtained in step 1) is coated on the obtained photonic crystal film, and then naturally dried and calcined to obtain a photocatalyst thin film.
5. The preparation method according to claim 4, characterized in that In the step 1), the water bath reflux time is 30 to 200 minutes; and the hydrothermal reaction time is 6 to 12 hours.
6. The preparation method according to claim 4, characterized in that In the step 1), the volume ratio of ethanol to water in the ethanol-water mixed solvent is 3-0.5:
1.
7. The preparation method according to claim 4, characterized in that In the step 2), the calcination temperature is 200-600° C. and the calcination time is 30-150 min.
8. The preparation method according to claim 4, characterized in that In the step 2), the photonic crystal film is prepared using SiO2 microspheres as raw materials. The specific steps are as follows: dispersing the SiO2 microspheres in an ethanol-water mixed solvent to obtain a SiO2 suspension; immersing a glass slide in the suspension at a certain angle so that only one side is dipped in the suspension, then slowly lifting the glass slide and placing it on a table with the side dipped in the suspension facing up, and calcining it after it is naturally dried to obtain a PCs film.
9. Use of the TiO2 / Bi2S3 / PCs composite photocatalyst film according to claim 1 in degrading antibiotics in wastewater.
10. The use according to claim 9, characterized in that The application is specifically as follows: placing a TiO2 / Bi2S3 / PCs composite photocatalyst film in an antibiotic solution, stirring in the dark until adsorption-desorption equilibrium is reached, and then irradiating with a xenon lamp light source.