Preparation method and application of molten salt-mediated CeO2 / Bi4TaO8Cl heterojunction catalyst
The CeO2/Bi4TaO8Cl heterojunction catalyst was prepared by a molten salt-mediated method, which solved the limitations of traditional iron-based photo-Fenton catalysts and the technical problems of synthesis and preparation methods, optimized the optical properties and surface structure, improved the utilization rate of photogenerated electrons and the efficiency of photogenerated carrier separation, enhanced the light capture ability, and significantly improved the photo-Fenton performance.
Patent Information
- Application Number
- CN202410111065.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-01-26
- Publication Date
- 2025-09-23
- Estimated Expiration
- 2044-01-26
AI Technical Summary
In the existing technology, traditional iron-based photo-Fenton catalysts have problems such as the inability to recover Fe2+/Fe3+, a narrow pH working range, and the generation of iron-containing sludge. In addition, traditional CeO2-based nanomaterial synthesis methods have limitations such as high pressure and high temperature, cumbersome operations, and are not conducive to large-scale production.
The CeO2/Bi4TaO8Cl heterojunction catalyst was prepared by a molten salt-mediated method. The CeO2/Bi4TaO8Cl heterojunction catalyst was prepared by hydrothermal treatment and calcination of sodium citrate, bismuth nitrate pentahydrate, potassium chloride and other components. The optical properties and surface structure of bismuth oxychloride nanosheets were optimized, and the Ce3+/Ce4+ redox reaction was promoted.
It improves the utilization rate of photogenerated electrons and the efficiency of photogenerated carrier separation, enhances the light capture ability, significantly improves the photo-Fenton performance, and has good recyclability and stability, making it suitable for the degradation of antibiotics in water.
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Abstract
Description
Technical Field
[0001] The present invention relates to a preparation method and application of a molten salt-mediated CeO2 / Bi4TaO8Cl heterojunction catalyst, belonging to the technical field of new pollutant control and wastewater resource utilization. Background Art
[0002] In recent decades, the overuse and abuse of antibiotics have caused water pollution problems. Antibiotics, as one of the most representative drugs, are often released directly into aquatic environments. Due to the persistence of microorganisms and poor antibiotic metabolism, most antibiotic pollutants accumulate in the environment, threatening aquatic ecosystems and public health. Currently, in order to address the ecological risks of antibiotic pollutants, photo-Fenton technology has been developed to degrade antibiotic pollutants in water bodies. However, traditional iron-based photo-Fenton catalysts have obvious limitations, such as the inability to recycle Fe 2+ / Fe 3+ , narrow pH working range, production of iron-containing sludge, etc. Therefore, it is very necessary to design an ultra-efficient and stable photo-Fenton reaction system.
[0003] Recent studies have shown that some non-Fe transition element (such as Mn, Fe, Co, Ce, Cu, etc.) based catalysts can replace traditional Fe based catalysts and promote the catalytic degradation of photo-Fenton system. Among various supporting materials, CeO2 is the representative of lanthanide rare earth oxides because of its Ce 3+ / Ce 4+ CeO2-based nanomaterials are playing an increasingly important role in photo-Fenton catalysis due to their reversible redox cycles, environmental friendliness, low cerium leaching rate, and good oxygen storage capacity. To date, various synthetic strategies have been reported for synthesizing CeO2-based nanomaterials, including solid-state reactions, sol-gel methods, microwave methods, and hydrothermal methods. However, these methods still suffer from limitations such as high pressure or high temperature, cumbersome procedures, and specific equipment requirements. These methods can result in low yields, poor reproducibility, and hinder stability and large-scale production. Summary of the Invention
[0004] The purpose of the present invention is to solve the deficiencies of the above-mentioned prior art and provide a molten salt-mediated CeO2 / Bi4TaO8Cl heterojunction catalyst preparation method and application. To achieve the above-mentioned purpose, the present invention adopts the following technical solutions:
[0005] (1) Sodium citrate is dissolved in a nitric acid solution containing bismuth nitrate pentahydrate, and the solution is stirred until dissolved to form a solution A, wherein the concentration of sodium citrate in the solution A is 200 to 400 mmol / L, the concentration of bismuth nitrate is 50 to 200 mmol / L, and the concentration of nitric acid is 0.06 to 0.10 mmol / L.
[0006] (2) Potassium chloride is added to the aqueous solution under magnetic stirring to obtain solution B, wherein the concentration of potassium chloride is 50 to 200 mmol / L.
[0007] (3) Solution A was added dropwise to solution B in a volume ratio of 1:1 and stirred at room temperature for 1 h. The suspension was transferred into a polyethylene-lined anti-oxidation steel autoclave for hydrothermal treatment and then naturally cooled to room temperature. The obtained product was washed to remove other ions, filtered, separated, and then dried to obtain BiOCl.
[0008] (4) BiOCl, bismuth oxide, tantalum oxide, KCl, and sodium chloride are ground and mixed, and then calcined in a muffle furnace. The obtained product is cooled, washed, and dried to obtain Bi4TaO8Cl.
[0009] (5) Grind and mix Bi4TaO8Cl, cerium nitrate hexahydrate, and potassium nitrate, calcine them in a muffle furnace, cool them, wash them, and dry them to obtain CeO2 / Bi4TaO8Cl.
[0010] Preferably, the reaction conditions in the oxidation-resistant steel autoclave in step (3) are: the insulation temperature is 140-200° C., the insulation time is 5-10 hours, and the obtained product is thoroughly washed three times with distilled water and anhydrous alcohol, respectively, filtered and separated to remove other ions, and then dried at 60-80° C. overnight.
[0011] Preferably, in step (4), the molar ratio of BiOCl, bismuth oxide, tantalum oxide, KCl and sodium chloride is 2:3:1:60:60.
[0012] Preferably, the calcination condition in the muffle furnace in step (4) is calcination at 600-800° C. for 7-28 hours.
[0013] Preferably, in step (5), the mass ratio of Bi4TaO8Cl to potassium nitrate is 1:6, and the mass ratio of cerium nitrate hexahydrate to Bi4TaO8Cl is 1:1 to 1:5.
[0014] Preferably, the calcination conditions in the muffle furnace in step (5) are calcination at 300-500°C for 4-16h, and the heating rate is 1-10°C·min -1 .
[0015] Preferably, the drying conditions in steps (3) to (5) are drying at 60 to 80° C. for 10 to 24 hours.
[0016] The invention discloses an application of the CeO2 / Bi4TaO8Cl heterojunction catalytic nanocomposite material prepared by the invention in degrading antibiotics in water.
[0017] More preferably, the prepared CeO2 / Bi4TaO8Cl heterojunction catalytic nanocomposite material has an effect on the degradation of ofloxacin (OFX), tetracycline (TC), norfloxacin (NOR), ciprofloxacin (CIP) and sulfamethoxazole in water.
[0018] The beneficial effects of the present invention are:
[0019] (1) The present invention adopts a molten salt-mediated strategy to study the controllable defect engineering of Bi4TaO8Cl nanosheets loaded with CeO2 nanodots and prepares CeO2 / Bi4TaO8Cl heterojunction catalysts. Compared with nanosheets prepared by traditional methods, this heterojunction has more reactive sites and can improve the utilization rate of photogenerated electrons, providing a new idea for the preparation and functionalization of molten salt-mediated bismuth oxychloride nanosheets / non-transition metal-based composite materials.
[0020] (2) The molten salt-mediated CeO2 / Bi4TaO8Cl heterojunction catalyst prepared by the present invention optimizes the optical properties and surface structure of bismuth oxychloride nanosheets and reduces the resistance of charge transfer.
[0021] (3) The CeO2 / Bi4TaO8Cl prepared by the present invention has enhanced light capture capability and higher photogenerated carrier separation efficiency and migration efficiency.
[0022] (4) The introduction of CeO2 can inhibit the recombination of photoinduced electron-hole pairs and significantly improve the photo-Fenton performance of CeO2 / Bi4TaO8Cl.
[0023] (5) In metal ions (Ce 3+ / Ce 4+ ) in the self-circulating reaction, Ce 3+ / Ce 4+ The redox couple can promote the decomposition of H2O2 to produce more ·OH, thereby improving the activity of the catalyst and providing a new idea for solving the key bottleneck problem of molten salt-mediated synthesis strategy in catalyst defect engineering.
[0024] (6) The prepared molten salt-mediated CeO2 / Bi4TaO8Cl heterojunction has good recyclability, stability, photocatalytic activity and environmental benefits.
[0025] (7) The equipment and materials required for the preparation method of the present invention are easy to obtain, the process operation is simple, and the process conditions are concise. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Figure 1 These are the XRD patterns of the heterojunctions prepared in Examples 1 to 5 and Comparative Example 1.
[0027] Figure 2Scanning electron microscope images of the Bi4TaO8Cl sample and the CE-BTC heterojunction prepared in Examples 1 to 5 (Figure a shows the nanosheet morphology of the Bi4TaO8Cl sample; Figures b to f show the nanosheet morphology of the CE-BTC heterojunction prepared in Examples 1 to 5).
[0028] Figure 3 UV-vis spectra of the heterojunctions and CeO2 prepared in Examples 1 to 5 and Comparative Example 1.
[0029] Figure 4 PL spectra of the heterojunctions prepared in Examples 1 to 5 and Comparative Example 1.
[0030] Figure 5 This is a comparison chart of the degradation performance of the heterojunction prepared in Examples 1 to 5 and Comparative Example 1 on OFX.
[0031] Figure 6 This is a comparison chart of the degradation performance of the CeO2 / Bi4TaO8Cl heterojunction prepared in Example 3 for TC, NOR, CIP and SMX. DETAILED DESCRIPTION
[0032] The present invention will be further described in detail below with reference to specific embodiments, but the protection scope of the present invention is not limited to the contents described above.
[0033] Example 1
[0034] The preparation method of the CeO2 / Bi4TaO8Cl heterojunction catalyst in this example includes the following steps:
[0035] (1) Preparation of BiOCl precursor: 4 mmol of citric acid and 2 mmol of Bi(NO3)3·5H2O were dissolved in 20 mL of HNO3 solution. The concentration of HNO3 solution was 0.08 mol L -1 , stirring until dissolved to form solution A.
[0036] (2) KCl was added to 20 mL of aqueous solution under magnetic stirring to obtain solution B. The concentration of potassium chloride in solution B was 100 mmol / L.
[0037] (3) Solution A was added dropwise to solution B in a volume ratio of 1:1 and stirred at room temperature for 1 h. The suspension was transferred into a 50 mL stainless steel autoclave lined with polytetrafluoroethylene and kept at 150 °C for 10 h, then naturally cooled to room temperature. The obtained product was thoroughly washed three times with distilled water and anhydrous alcohol, respectively, and filtered to remove other ions. The obtained BiOCl was dried at 80 °C overnight.
[0038] (4) Preparation of Bi4TaO8Cl heterojunction catalyst: BiOCl, bismuth oxide (Bi2O3), tantalum oxide (Ta2O5), KCl, and sodium chloride (NaCl) were ground and mixed, and calcined in a muffle furnace at 700°C for 14 h. The resulting product was cooled, washed, and dried to obtain Bi4TaO8Cl, wherein the molar ratio of BiOCl, bismuth oxide (Bi2O3), tantalum oxide (Ta2O5), KCl, and sodium chloride (NaCl) was 2:3:1:60:60.
[0039] (5) 1 g Bi4TaO8Cl and 6 g KNO3 were mixed with 0.2 g Ce(NO3)3·6H2O in agate mortar and ground for 30 min. The mixture was calcined in a muffle furnace at 400 °C for 8 h (heating rate of 2 °C·min -1 ), the obtained mixture was washed and dried at 80°C for 10 h, and the obtained CeO2 / Bi4TaO8Cl heterojunction was designated as CE-BTC-1.
[0040] Example 2
[0041] The preparation method of the CeO2 / Bi4TaO8Cl heterojunction catalyst in this example includes the following steps:
[0042] (1) Preparation of BiOCl precursor: 4 mmol of citric acid and 2 mmol of Bi(NO3)3·5H2O were dissolved in 20 mL of HNO3 solution. The concentration of HNO3 solution was 0.08 mol L -1 , stirring until dissolved to form solution A.
[0043] (2) KCl was added to 20 mL of aqueous solution under magnetic stirring to obtain solution B. The concentration of potassium chloride in solution B was 100 mmol / L.
[0044] (3) Solution A was added dropwise to solution B in a volume ratio of 1:1 and stirred at room temperature for 1 h. The suspension was transferred into a 50 mL stainless steel autoclave lined with polytetrafluoroethylene and kept at 150 °C for 10 h, then naturally cooled to room temperature. The obtained product was thoroughly washed three times with distilled water and anhydrous alcohol, respectively, and filtered to remove other ions. The obtained BiOCl was dried at 80 °C overnight.
[0045] (4) Preparation of Bi4TaO8Cl heterojunction catalyst: BiOCl, bismuth oxide (Bi2O3), tantalum oxide (Ta2O5), KCl, and sodium chloride (NaCl) were ground and mixed, and calcined in a muffle furnace at 700°C for 14 h. The resulting product was cooled, washed, and dried to obtain Bi4TaO8Cl, wherein the molar ratio of BiOCl, bismuth oxide (Bi2O3), tantalum oxide (Ta2O5), KCl, and sodium chloride (NaCl) was 2:3:1:60:60.
[0046] (5) 1 g Bi4TaO8Cl and 6 g KNO3 were mixed with 0.4 g Ce(NO3)3·6H2O in agate mortar and ground for 30 min. The mixture was calcined in a muffle furnace at 400 °C for 8 h (heating rate of 2 °C·min -1 ), the obtained mixture was washed and dried at 80°C for 10 h, and the obtained CeO2 / Bi4TaO8Cl heterojunction was recorded as CE-BTC-2.
[0047] Example 3
[0048] The preparation method of the CeO2 / Bi4TaO8Cl heterojunction catalyst in this example includes the following steps:
[0049] (1) Preparation of BiOCl precursor: 4 mmol of citric acid and 2 mmol of Bi(NO3)3·5H2O were dissolved in 20 mL of HNO3 solution. The concentration of HNO3 solution was 0.08 mol L -1 , stirring until dissolved to form solution A.
[0050] (2) KCl was added to 20 mL of aqueous solution under magnetic stirring to obtain solution B. The concentration of potassium chloride in solution B was 100 mmol / L.
[0051] (3) Solution A was added dropwise to solution B in a volume ratio of 1:1 and stirred at room temperature for 1 h. The suspension was transferred into a 50 mL stainless steel autoclave lined with polytetrafluoroethylene and kept at 150 °C for 10 h, then naturally cooled to room temperature. The obtained product was thoroughly washed three times with distilled water and anhydrous alcohol, respectively, and filtered to remove other ions. The obtained BiOCl was dried at 80 °C overnight.
[0052] (4) Preparation of Bi4TaO8Cl heterojunction catalyst: BiOCl, bismuth oxide (Bi2O3), tantalum oxide (Ta2O5), KCl, and sodium chloride (NaCl) were ground and mixed, and calcined in a muffle furnace at 700°C for 14 h. The resulting product was cooled, washed, and dried to obtain Bi4TaO8Cl, wherein the molar ratio of BiOCl, bismuth oxide (Bi2O3), tantalum oxide (Ta2O5), KCl, and sodium chloride (NaCl) was 2:3:1:60:60.
[0053] (5) 1 g Bi4TaO8Cl and 6 g KNO3 were mixed with 0.6 g Ce(NO3)3·6H2O in agate mortar and ground for 30 min. The mixture was calcined in a muffle furnace at 400 °C for 8 h (heating rate of 2 °C·min -1 ), the obtained mixture was washed and dried at 60°C for 10 h, and the obtained CeO2 / Bi4TaO8Cl heterojunction was recorded as CE-BTC-3.
[0054] Example 4
[0055] The preparation method of the CeO2 / Bi4TaO8Cl heterojunction catalyst in this example includes the following steps:
[0056] (1) Preparation of BiOCl precursor: 4 mmol of citric acid and 2 mmol of Bi(NO3)3·5H2O were dissolved in 20 mL of HNO3 solution. The concentration of HNO3 solution was 0.08 mol L -1 , stirring until dissolved to form solution A.
[0057] (2) KCl was added to 20 mL of aqueous solution under magnetic stirring to obtain solution B. The concentration of potassium chloride in solution B was 100 mmol / L.
[0058] (3) Solution A was added dropwise to solution B in a volume ratio of 1:1 and stirred at room temperature for 1 h. The suspension was transferred into a 50 mL stainless steel autoclave lined with polytetrafluoroethylene and kept at 150 °C for 10 h, then naturally cooled to room temperature. The obtained product was thoroughly washed three times with distilled water and anhydrous alcohol, respectively, and filtered to remove other ions. The obtained BiOCl was dried at 80 °C overnight.
[0059] (4) Preparation of Bi4TaO8Cl heterojunction catalyst: BiOCl, bismuth oxide (Bi2O3), tantalum oxide (Ta2O5), KCl, and sodium chloride (NaCl) were ground and mixed, and calcined in a muffle furnace at 700°C for 14 h. The resulting product was cooled, washed, and dried to obtain Bi4TaO8Cl, wherein the molar ratio of BiOCl, bismuth oxide (Bi2O3), tantalum oxide (Ta2O5), KCl, and sodium chloride (NaCl) was 2:3:1:60:60.
[0060] (5) 1 g Bi4TaO8Cl and 6 g KNO3 were mixed with 0.8 g Ce(NO3)3·6H2O in agate mortar and ground for 30 min. The mixture was calcined in a muffle furnace at 400 °C for 8 h (heating rate of 2 °C·min -1 ), the obtained mixture was washed and dried at 80°C for 10 h, and the obtained CeO2 / Bi4TaO8Cl heterojunction was recorded as CE-BTC-4.
[0061] Example 5
[0062] The preparation method of the CeO2 / Bi4TaO8Cl heterojunction catalyst in this example includes the following steps:
[0063] (1) Preparation of BiOCl precursor: 4 mmol of citric acid and 2 mmol of Bi(NO3)3·5H2O were dissolved in 20 mL of HNO3 solution. The concentration of HNO3 solution was 0.08 mol L -1 , stirring until dissolved to form solution A.
[0064] (2) KCl was added to 20 mL of aqueous solution under magnetic stirring to obtain solution B. The concentration of potassium chloride in solution B was 100 mmol / L.
[0065] (3) Solution A was added dropwise to solution B in a volume ratio of 1:1 and stirred at room temperature for 1 h. The suspension was transferred into a 50 mL stainless steel autoclave lined with polytetrafluoroethylene and kept at 150 °C for 10 h, then naturally cooled to room temperature. The obtained product was thoroughly washed three times with distilled water and anhydrous alcohol, respectively, and filtered to remove other ions. The obtained BiOCl was dried at 80 °C overnight.
[0066] (4) Preparation of Bi4TaO8Cl heterojunction catalyst: BiOCl, bismuth oxide (Bi2O3), tantalum oxide (Ta2O5), KCl, and sodium chloride (NaCl) were ground and mixed, and calcined in a muffle furnace at 700°C for 14 h. The resulting product was cooled, washed, and dried to obtain Bi4TaO8Cl, wherein the molar ratio of BiOCl, bismuth oxide (Bi2O3), tantalum oxide (Ta2O5), KCl, and sodium chloride (NaCl) was 2:3:1:60:60.
[0067] (5) 1 g Bi4TaO8Cl and 6 g KNO3 were mixed with 1.0 g Ce(NO3)3·6H2O in agate mortar and ground for 30 min. The mixture was calcined in a muffle furnace at 400 °C for 8 h (heating rate of 2 °C·min -1 ), the obtained mixture was washed and dried at 80°C for 10 h, and the obtained CeO2 / Bi4TaO8Cl heterojunction was recorded as CE-BTC-5.
[0068] Comparative Example 1
[0069] This comparative example uses a molten salt method to prepare a Bi4TaO8Cl catalyst, comprising the following steps:
[0070] (1) The preparation method of the precursors BiOCl and Bi4TaO8Cl is the same as that in Example 1.
[0071] (2) Preparation of Bi4TaO8Cl: BiOCl, Bi2O3, Ta2O5, KCl, and NaCl in a molar ratio of 2:3:1:60:60 were ground for about 30 minutes, calcined in a muffle furnace at 700°C for 14 hours, cooled, washed with hot deionized water and ethanol, and dried at 80°C for 10 hours to obtain Bi4TaO8Cl.
[0072] The CeO2 / Bi4TaO8Cl heterojunctions prepared in Examples 1 to 5, the Bi4TaO8Cl catalyst prepared in Comparative Example 1, and CeO2 were subjected to X-ray diffraction experiments. The results are as follows: Figure 1 As shown in the figure, it can be seen that the CeO2 / Bi4TaO8Cl heterojunction not only has the characteristic peaks of Bi4TaO8Cl, but also corresponds well to the (111) surface of CeO2, confirming the construction of the CeO2 / Bi4TaO8Cl composite material.
[0073] The prepared Bi4TaO8Cl catalyst was observed using a scanning electron microscope. Figure 2 As shown in a, the Bi4TaO8Cl sample obtained in the molten salt system has a nanosheet morphology. Figure 2Figures b-2f show the CE-BTC heterojunctions prepared in Examples 1-5, respectively. It is clearly evident that the CeO2 nanodots deposited on the Bi4TaO8Cl nanosheets maintain their original nanosheet morphology and are evenly dispersed across the Bi4TaO8Cl nanosheets. The number of CeO2 nanodots deposited on the Bi4TaO8Cl surface increases with increasing cerium nitrate hexahydrate content in the heterojunction.
[0074] The light capture capabilities of the CeO2 / Bi4TaO8Cl heterojunctions prepared in Examples 1 to 5, the Bi4TaO8Cl catalyst prepared in Comparative Example 1, and CeO2 were tested. Figure 3 As shown in the figure, it can be seen that the absorption edges of Bi4TaO8Cl and CeO2 are located at 494.02nm and 487.76nm respectively, while the absorption edge of CeO2 / Bi4TaO8Cl shows an obvious red shift, indicating that the light capture ability of the CeO2 / Bi4TaO8Cl heterojunction is enhanced.
[0075] The CeO2 / Bi4TaO8Cl heterojunction prepared in Examples 1 to 5 and the Bi4TaO8Cl catalyst prepared in Comparative Example 1 were tested for current density. The results are as follows: Figure 4 As shown in the figure, it can be seen that the photocurrent of CeO2 / Bi4TaO8Cl is significantly increased compared with Bi4TaO8Cl, indicating that the recombination efficiency of photogenerated carriers in the CeO2 / Bi4TaO8Cl heterojunction is low, and the separation and migration efficiency of photogenerated carriers are low. In addition, the introduction of CeO2 can inhibit the recombination of photoinduced electron-hole pairs, thereby significantly improving the photo-Fenton activity of the CeO2 / Bi4TaO8Cl heterojunction.
[0076] Photo-Fenton degradation experiment
[0077] The CeO2 / Bi4TaO8Cl heterojunction obtained in Example 1, the Bi4TaO8Cl catalyst obtained in Comparative Example 1, and CeO2 were used for photo-Fenton degradation of antibiotics, respectively, in the following specific steps:
[0078] (1) 10 mg of CeO2 / Bi4TaO8Cl heterojunction catalyst, Bi4TaO8Cl catalyst, and CeO2 were weighed and dispersed into 50 mL of antibiotic aqueous solution (antibiotic concentration was 20 mg / L), stirred for 30 min in the dark, and appropriately ultrasonically dispersed to achieve adsorption-desorption equilibrium.
[0079] (2) The energy intensity of the simulated sunlight source is 73 mW·cm -2A 5W white LED lamp was used, and (4.5 mM, 30% w / w) H2O2 solution was added and placed under the light source for irradiation to initiate the photo-Fenton reaction.
[0080] (3) Every 30 minutes, 5 mL of solution was taken and the absorbance of the antibiotics was measured using a UV-visible spectrophotometer (UV-1800PC). Ofloxacin (OFX), tetracycline (TC), norfloxacin (NOR), ciprofloxacin (CIP), and sulfamethoxazole (SMX) were measured at absorbances of λ = 288, 357, 277, and 277 nm. The concentrations of the antibiotics were further calculated based on the standard curve of absorbance and concentration. The results are shown in Figure 2. Figures 5-6 shown.
[0081] from Figure 5 It can be seen that the OFX removal rates of Bi4TaO8Cl and CeO2 samples within 40 min are only 35.88% and 50.89%, respectively. The introduction of CeO2 can improve the photo-Fenton activity of Bi4TaO8Cl. Among them, the photo-Fenton degradation efficiency of CE-BTC-3 sample is the highest (98.78%), which is 7.79 times and 4.98 times that of Bi4TaO8Cl and CeO2, respectively.
[0082] from Figure 6 It can be seen that the photo-Fenton degradation efficiencies of TC, NOR, CIP and SMX on CE-BTC-3 reached approximately 99.98%, 96.39%, 92.51% and 70.69% within 40 min, respectively, indicating that the CE-BTC heterojunction has wide applicability for degradation of antibiotics.
[0083] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present invention, and without departing from the spirit and scope of the technical solution of the present invention, which is defined by the appended claims and their equivalents.
Claims
1. Application of a molten salt-mediated CeO2 / Bi4TaO8Cl heterojunction catalyst in photo-Fenton degradation of antibiotics in water, characterized by: The preparation method of the heterojunction catalyst comprises the following steps: (1) Dissolve sodium citrate in a nitric acid solution containing bismuth nitrate pentahydrate and stir until dissolved to form solution A, wherein the concentration of sodium citrate in solution A is 200-400 mmol / L, the concentration of bismuth nitrate is 50-200 mmol / L, and the concentration of nitric acid is 0.06-0.10 mmol / L; (2) Potassium chloride was added to the aqueous solution under magnetic stirring to obtain solution B, where the concentration of potassium chloride was 50-200 mmol / L; (3) Solution A was added dropwise to solution B at a volume ratio of 1:1 and stirred at room temperature for 1 h. The suspension was transferred into a polytetrafluoroethylene-lined anti-oxidation steel autoclave for hydrothermal treatment and then naturally cooled to room temperature. The obtained product was washed to remove other ions, filtered, separated, and then dried to obtain BiOCl. (4) Grind and mix BiOCl, bismuth oxide, tantalum oxide, KCl, and sodium chloride, and then calcine in a muffle furnace. The resulting product is cooled, washed, and dried to obtain Bi4TaO8Cl; (5) Grind and mix Bi4TaO8Cl, cerium nitrate hexahydrate, and potassium nitrate, calcine them in a muffle furnace, cool them, wash them, and dry them to obtain CeO2 / Bi4TaO8Cl.
2. The use according to claim 1, characterized in that: The reaction conditions in the oxidation-resistant steel autoclave in step (3) are as follows: the holding temperature is 140-200°C, the holding time is 5-10 h, and the obtained product is thoroughly washed three times with distilled water and anhydrous alcohol, respectively, and filtered to remove other ions, and then dried at 60-80°C overnight.
3. The use according to claim 1, characterized in that: The molar ratio of BiOCl, bismuth oxide, tantalum oxide, KCl and sodium chloride in step (4) is 2:3:1:60:
60.
4. The use according to claim 1, characterized in that: The calcination conditions in the muffle furnace in step (4) are calcination at 600-800°C for 7-28 h.
5. The use according to claim 1, characterized in that: In step (5), the mass ratio of Bi4TaO8Cl to potassium nitrate is 1:6, and the mass ratio of cerium nitrate hexahydrate to Bi4TaO8Cl is 1:1~1:
5.
6. The use according to claim 1, characterized in that: The calcination conditions in the muffle furnace in step (5) are calcination at 300-500°C for 4-16 h, and the heating rate is 1-10°C·min -1 .
7. The use according to claim 1, characterized in that: The drying conditions in steps (3) to (5) are drying at 60 to 80°C for 10 to 24 hours.