Preparation method of tetracycline photocatalyst
By preparing a metal-organic framework material with molybdenum-sulfur active centers, the problems of low efficiency and poor stability of photocatalytic materials were solved, achieving efficient degradation of tetracycline wastewater. It has good anti-interference and stability and is suitable for large-scale application.
Patent Information
- Application Number
- CN202511074110.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-01
- Publication Date
- 2025-11-11
- Estimated Expiration
- Not applicable · inactive patent
Smart Images
Figure BDA0005528779610000081
Abstract
Description
Technical Field
[0001] This invention relates to the field of environmental catalytic materials technology, specifically to a method for preparing a tetracycline photocatalyst. Background Technology
[0002] The use and discharge of antibiotics mainly originate from medical, agricultural, and livestock industries. Hospital wastewater, domestic sewage, and wastewater from aquaculture and animal husbandry contain large amounts of antibiotics, which ultimately enter water bodies, causing pollution of surface water, groundwater, sediments, and soil.
[0003] Antibiotic contamination accelerates the spread of drug-resistant bacteria ("superbugs"). The long-term presence of low-dose antibiotics in the environment can screen out drug-resistant genes, leading to increased drug resistance in human and animal infections. Antibiotics also damage ecosystems, inhibiting the activity of beneficial microorganisms, affecting soil fertility and plant growth. Fish, algae, and other organisms may experience developmental abnormalities or die due to antibiotic accumulation, disrupting the food chain. Humans may ingest low-dose antibiotics through the food chain or drinking water, potentially causing problems such as allergies and gut microbiota dysbiosis.
[0004] Traditional methods for treating antibiotic wastewater have many limitations. Activated sludge processes are time-consuming, require multiple rounds of microbial acclimatization, and have limited antibiotic removal rates; adsorption methods face difficulties in treating adsorbents after saturation; membrane separation technologies are costly and prone to membrane fouling. With increasing public awareness of environmental protection and health safety, the development of efficient, low-cost, and environmentally friendly antibiotic degradation technologies is urgently needed.
[0005] Currently, photocatalysis technology is a promising green technology with core advantages in environmental protection, energy conservation, and sustainability. It directly utilizes sunlight as an energy source, eliminating the need for large amounts of electricity or fossil fuels, resulting in low operating costs and no secondary pollution. In environmental remediation, photocatalysis can efficiently decompose organic pollutants in water (such as pesticides, dyes, and drug residues), kill bacteria and viruses, and even purify harmful gases in the air (such as formaldehyde and nitrogen oxides). Furthermore, it can convert carbon dioxide into fuels such as methane and methanol, achieving carbon resource recycling and contributing to carbon neutrality goals. In the energy sector, photocatalytic water splitting for hydrogen production is considered a crucial direction for future clean energy. Compared to traditional high-temperature, high-pressure industrial processes, photocatalytic reactions typically occur at room temperature and pressure, making them safer, more controllable, and suitable for various applications.
[0006] Disadvantages: Despite the immense potential of photocatalysis, current materials still face several key bottlenecks. The most prominent issue is insufficient efficiency—most photocatalytic materials (such as titanium dioxide) can only utilize the ultraviolet portion of sunlight (approximately 5%), while their utilization efficiency for the visible light (approximately 50%), which constitutes the majority of sunlight, is extremely low, resulting in slow overall reaction rates and low energy conversion rates. Furthermore, electrons and holes generated under illumination readily recombine instead of participating in the catalytic reaction, leading to a significant waste of light energy. Stability is also a challenge; many catalysts are prone to deactivation after long-term use, for example, due to contaminant accumulation, photocorrosion of their structure, or chemical degradation. Finally, many difficulties remain in transitioning from the laboratory to practical applications, such as how to mass-produce high-performance catalysts at low cost, how to design efficient photoreactors, and how to maintain catalytic efficiency in real-world environments (such as industrial wastewater and complex atmospheric conditions). Solving these problems will determine whether photocatalysis technology can truly achieve large-scale commercial application.
[0007] In conclusion, developing a photocatalytic material that is highly stable, has excellent degradation efficiency, is cost-effective, and adaptable to complex aquatic environments is of great significance for the practical treatment of tetracycline antibiotic wastewater. Summary of the Invention
[0008] The purpose of this invention is to provide a method for preparing tetracycline photocatalysts, which can effectively solve the problems of low efficiency and poor stability of existing photocatalytic materials.
[0009] To achieve the above objectives, the technical solution provided by the present invention is as follows:
[0010] A method for preparing a tetracycline photocatalyst, characterized by comprising the following steps:
[0011] Step 1: Synthesis of 100 Iron Metal-Organic Frameworks
[0012] (1) Mix the iron salt and pyromellitic acid and dissolve them in distilled water, stirring until completely dissolved;
[0013] (2) Transfer the mixture of (1) to a polytetrafluoroethylene-lined high-pressure reactor and react at room temperature to 150°C for 12 to 16 hours.
[0014] (3) After the solution in (2) is cooled naturally, it is centrifuged and the supernatant is removed. The lower precipitate is washed three times with ethanol and then freeze-dried under vacuum at -30 to -50°C for 12 hours to obtain MIL-100(Fe) powder.
[0015] Step 2: Preparation of Degradable Composite Materials
[0016] Option 1
[0017] (1) Disperse the dried MIL-100(Fe) in 60 mL of deionized water by ultrasonication to form a uniform suspension;
[0018] (2) Add ammonium molybdate and thiourea in sequence, and stir for 30 minutes until fully mixed;
[0019] (3) Transfer the mixture to a high-pressure reactor and hydrothermally react at 80-200°C for 14-16 hours;
[0020] (4) After centrifugation and collection of the product, it was washed three times with ethanol and then freeze-dried in vacuum at -30 to -50°C for 12 hours to obtain a brown powdery degradation composite material.
[0021] Option 2
[0022] (1) Disperse the dried MIL-100(Fe) in 60 mL of deionized water by ultrasonication to form a uniform suspension;
[0023] (2) Add ammonium molybdate and thiourea in sequence, and stir for 30 minutes until fully mixed;
[0024] (3) Add 10 mL of 0.1 mol / L hydrochloric acid solution to (2);
[0025] (4) Transfer the mixture to a high-pressure reactor and hydrothermally react at 80-200°C for 14-16 hours;
[0026] (5) After centrifugation and collection of the product, it was washed three times with ethanol and then freeze-dried in vacuum at -30 to -50°C for 12 hours to obtain a brown powdery degradation composite material.
[0027] The preparation method of the degradable material described in this invention differs from conventional physical adsorption or chemical precipitation methods. It utilizes hydrothermal synthesis technology to achieve high dispersion of active components (molybdenum and sulfur) on the MIL-100 (Fe) carrier through a high-pressure reactor reaction. Simultaneously, ammonium molybdate is converted into highly active molybdenum species, and the pyrolysis process of thiourea can be controlled to form a uniform sulfur-doped structure, thereby enhancing the material's degradation performance.
[0028] The preparation method of the degradable material described in this invention differs from the traditional fixed-bed loading process. It achieves nano-sized (particle size less than 10 nm) and uniform loading of active components under high pressure through hydrothermal reaction. The high-pressure environment helps to form a stable metal-organic framework composite structure, improving the accessibility of active sites and reaction efficiency.
[0029] The degradation material containing molybdenum-sulfur active centers described in this invention significantly enhances the catalytic degradation ability of tetracycline through the synergistic effect of the redox properties of molybdenum species and sulfur. The introduction of sulfur also optimizes the electronic structure of the material surface, enhancing the adsorption and activation of pollutants.
[0030] The present invention optimizes the loading and chemical state of active components by adjusting the hydrothermal reaction temperature and pH value, thereby reducing the amount of molybdenum used while maintaining high degradation performance.
[0031] The beneficial effects achieved by the present invention using the above method are as follows:
[0032] 1. It can achieve efficient degradation of tetracycline under normal temperature and pressure;
[0033] 2. Good moisture resistance and anti-interference ability;
[0034] 3. Low content of active ingredients, controllable cost;
[0035] 4. The structure is stable, not easily deactivated, and has high recycling efficiency. Detailed Implementation
[0036] Example 1
[0037] Preparation of the carrier: 1.62 g of ferric chloride hexahydrate and 0.42 g of trimesic acid were dissolved in 50 mL of distilled water and stirred until completely dissolved. The solution was then transferred to an autoclave and reacted at 150 °C for 12 hours. After centrifugation and washing with ethanol, the solution was freeze-dried under vacuum at -40 °C for 12 hours and designated as carrier Z-1.
[0038] Preparation of MOS2@Z-1 catalyst: 0.1g Z-1 suspension, 0.2g ammonium molybdate, and 0.6g thiourea were mixed, transferred to an autoclave, and hydrothermally reacted at 180℃ for 12 hours. After centrifugation and washing with ethanol, the catalyst was freeze-dried under vacuum at -40℃ for 12 hours to obtain the degradation material.
[0039] Evaluation tests showed that the catalyst prepared using this method had a degradation rate of 94.5% at a tetracycline concentration of 15 mg / L.
[0040] Example 2
[0041] Preparation of the carrier: 1.8 g of ferric chloride hexahydrate and 0.6 g of trimesic acid were dissolved in 60 mL of distilled water. 5% HCl solution was added dropwise to adjust the pH to 3. The mixture was then transferred to an autoclave and reacted at 180 °C for 14 hours. After centrifugation and washing with ethanol, the mixture was freeze-dried under vacuum at -50 °C for 14 hours and designated as carrier Z-2.
[0042] Preparation of MOS2@Z-2: 0.5g Z-2 suspension and 0.5g ammonium molybdate and 1.0g thiourea were mixed, transferred to an autoclave, and hydrothermally reacted at 180℃ for 14 hours. After centrifugation and washing with ethanol, the degradable material was obtained after vacuum freeze-drying at -50℃ for 14 hours.
[0043] Evaluation tests showed that the catalyst prepared using this method had a degradation rate of 92.1% at a tetracycline concentration of 20 mg / L.
[0044] Example 3
[0045] Preparation of the carrier: 1.62 g of ferric nitrate hydrate and 0.42 g of trimesic acid were dissolved in 50 mL of distilled water and stirred until completely dissolved. The solution was then transferred to an autoclave and reacted at 140 °C for 12 hours. After centrifugation and washing with ethanol, the solution was freeze-dried under vacuum at -40 °C for 12 hours and designated as carrier Z-3.
[0046] Preparation of MOS2@Z-3 catalyst: 0.3g Z-3 suspension, 0.2g ammonium molybdate, and 0.6g thiourea were mixed, transferred to an autoclave, and hydrothermally reacted at 140℃ for 12 hours. After centrifugation and washing with ethanol, the catalyst was freeze-dried under vacuum at -40℃ for 12 hours to obtain the degradation material.
[0047] Evaluation tests showed that the catalyst prepared using this method had a degradation rate of 91.5% at a tetracycline concentration of 15 mg / L.
[0048] Example 4
[0049] Preparation of the carrier: 1.8 g of ferric nitrate hydrate and 0.6 g of trimesic acid were dissolved in 60 mL of distilled water. 5% HNO3 solution was added dropwise to adjust the pH to 4. The mixture was then transferred to an autoclave and reacted at 200 °C for 14 hours. After centrifugation and washing with ethanol, the mixture was freeze-dried under vacuum at -50 °C for 14 hours and designated as carrier Z-4.
[0050] Preparation of MOS2@Z-4: 0.6g Z-4 suspension and 0.7g sodium molybdate and 1.3g thiourea were mixed, transferred to an autoclave, and hydrothermally reacted at 200℃ for 16 hours. After centrifugation and washing with ethanol, the material was freeze-dried under vacuum at -50℃ for 16 hours to obtain the degradation material.
[0051] Evaluation tests showed that the catalyst prepared using this method had a degradation rate of 90.2% at a tetracycline concentration of 15 mg / L.
[0052] Example 5
[0053] Preparation of the carrier: 1.8 g of ferric nitrate hydrate and 0.6 g of trimesic acid were dissolved in 60 mL of distilled water. 5% HNO3 solution was added dropwise to adjust the pH to 5. The mixture was then transferred to an autoclave and reacted at 180 °C for 14 hours. After centrifugation and washing with ethanol, the mixture was freeze-dried under vacuum at -50 °C for 14 hours and designated as carrier Z-5.
[0054] Preparation of MOS2@Z-5: 0.5g Z-5 suspension and 0.5g sodium molybdate and 1.0g thiourea were mixed, transferred to an autoclave, and hydrothermally reacted at 180℃ for 14 hours. After centrifugation and washing with ethanol, the material was freeze-dried under vacuum at -50℃ for 14 hours to obtain the degradation material.
[0055] Evaluation tests showed that the catalyst prepared using this method had a degradation rate of 90.7% at a tetracycline concentration of 20 mg / L.
[0056] Comparative Example 1
[0057] Preparation of the carrier: 1.82 g of ferric sulfate hexahydrate and 0.62 g of trimesic acid were dissolved in 60 mL of distilled water and stirred until completely dissolved. The solution was then transferred to an autoclave and reacted at 150 °C for 12 hours. After centrifugation and washing with ethanol, the solution was freeze-dried under vacuum at -40 °C for 12 hours and designated as carrier Z-1.
[0058] Preparation of MOS2@Z-1 catalyst: 0.4g Z-1 suspension, 0.3g ammonium molybdate, and 0.7g thioacetamide were mixed, transferred to an autoclave, and hydrothermally reacted at 180℃ for 12 hours. After centrifugation and washing with ethanol, the catalyst was freeze-dried under vacuum at -40℃ for 12 hours to obtain the degradation material.
[0059] Evaluation tests showed that the catalyst prepared using this method had a degradation rate of 88.7% at a tetracycline concentration of 15 mg / L.
[0060] Comparative Example 2
[0061] Preparation of the carrier: 1.82 g of ferric nitrate hydrate and 0.62 g of terephthalic acid were dissolved in 60 mL of distilled water and stirred until completely dissolved. The solution was then transferred to an autoclave and reacted at 150 °C for 12 hours. After centrifugation and washing with ethanol, the solution was freeze-dried under vacuum at -40 °C for 12 hours and designated as carrier Z-2.
[0062] Preparation of MOS2@Z-2 catalyst: 0.4g Z-2 suspension, 0.3g sodium molybdate, and 0.7g thiourea were mixed, transferred to an autoclave, and hydrothermally reacted at 180℃ for 12 hours. After centrifugation and washing with ethanol, the catalyst was freeze-dried under vacuum at -40℃ for 12 hours to obtain the degradation material.
[0063] Evaluation tests showed that the catalyst prepared using this method had a degradation rate of 86.5% at a tetracycline concentration of 15 mg / L.
[0064] Comparative Example 3
[0065] Preparation of the carrier: 1.82 g of ferric chloride hexahydrate and 0.62 g of terephthalic acid were dissolved in 60 mL of distilled water and stirred until completely dissolved. The solution was then transferred to an autoclave and reacted at 180 °C for 12 hours. After centrifugation and washing with ethanol, the solution was freeze-dried under vacuum at -40 °C for 12 hours and designated as carrier Z-3.
[0066] Preparation of MOS2@Z-3 catalyst: 0.4g Z-3 suspension, 0.3g sodium molybdate, and 0.7g thioacetamide were mixed, transferred to an autoclave, and hydrothermally reacted at 180℃ for 12 hours. After centrifugation and washing with ethanol, the catalyst was freeze-dried under vacuum at -40℃ for 12 hours to obtain the degradation material.
[0067] Evaluation tests showed that the catalyst prepared using this method had a degradation rate of 85.4% at a tetracycline concentration of 15 mg / L.
[0068] The degradation rate test method is as follows:
[0069] 1. Using tetracycline as the target pollutant, a photocatalytic degradation experiment was conducted using an ultraviolet spectrophotometer;
[0070] 2. Prepare 200 mL of tetracycline solution with a concentration of 10-20 mg / L;
[0071] 3. Measure the initial photometric value using a UV spectrophotometer;
[0072] 4. Weigh different masses (weights) of the composite material and add them to the tetracycline solution prepared in step 2. Stir magnetically for 30 minutes under light-protected conditions (wrapped in tin foil).
[0073] 5. Then irradiate under visible light, and take 3 mL samples every 20 min for a total of 6 times;
[0074] 5. Remove the catalyst by filtration with a filter membrane, then measure the photometric value of the filtrate using a UV spectrophotometer, and finally calculate the degradation rate of tetracycline according to the following formula;
[0075] 7. Degradation rate = A0 - At / A0 × 100%
[0076] 8. In the formula: A0 (mg / L) is the initial photometric value of the tetracycline solution, and At (mg / L) is the absorbance of the solution at time t during photocatalytic degradation;
[0077] 9. Finally, the final degradation rate was measured.
[0078] Summary Analysis
[0079]
[0080] 1. Optimal combination:
[0081] FeCl3·6H2O + Tris(methyl pyromellitic acid) + Thiourea + Ammonium molybdate
[0082] 2. Technological advantages:
[0083] Tristyric acid is an essential ligand (comparative examples 2-3, degradation rate ↓ 5-9%);
[0084] Thiourea is not a substitute (comparative sample 1 / 3, degradation rate ↓ 1.8–5.1%);
[0085] An acidic environment improves molybdenum dispersion (Example 2 compared to Example 1, efficiency increased by 2.4% at the same concentration).
[0086] 3. Anti-interference verification:
[0087] The degradation rates of Comparative Examples 1 (ferric sulfate + thioacetamide) and 3 (non-preferred ligand + sulfur source) were significantly reduced, demonstrating that the selection of components in this invention has a non-negligible synergistic effect.
[0088] The present invention and its embodiments have been described above. This description is not restrictive. In summary, if anyone skilled in the art is inspired by this description and designs a method or embodiment similar to the technical solution without departing from the spirit of the present invention, such method or embodiment should be within the scope of protection of the present invention.
Claims
1. A method for preparing a tetracycline photocatalyst, characterized in that, Includes the following steps: Step 1: Synthesis of 100 Iron Metal-Organic Frameworks (1) Mix the iron salt and pyromellitic acid and dissolve them in distilled water, stirring until completely dissolved; (2) Transfer the mixture of (1) to a high-pressure reactor and react at room temperature to 150°C for 12 to 16 hours; (3) After the solution in (2) is cooled naturally, it is centrifuged and the supernatant is removed. The lower precipitate is washed three times with ethanol and then freeze-dried under vacuum at -30 to -50°C for 12 hours to obtain MIL-100(Fe) powder. Step 2: Preparation of Degradable Composite Materials Option 1 (1) Disperse the dried MIL-100(Fe) in 60 mL of deionized water by ultrasonication to form a uniform suspension; (2) Add ammonium molybdate and thiourea in sequence, and stir for 30 minutes until fully mixed; (3) Transfer the mixture to a high-pressure reactor and hydrothermally react at 80-200°C for 14-16 hours; (4) The product was collected by centrifugation, washed three times with ethanol, and then freeze-dried in vacuum at -30 to -50°C for 12 hours to obtain a brown powdery degradation composite material. Option 2 (1) Disperse the dried MIL-100(Fe) in 60 mL of deionized water by ultrasonication to form a uniform suspension; (2) Add ammonium molybdate and thiourea in sequence, and stir for 30 minutes until fully mixed; (3) Add 10 mL of 0.1 mol / L hydrochloric acid solution to (2); (4) Transfer the mixture to a high-pressure reactor and hydrothermally react at 80-200°C for 14-16 hours; (5) The product was collected by centrifugation, washed three times with ethanol, and then freeze-dried in vacuum at -30 to -50°C for 12 hours to obtain a brown powdery degradation composite material.
2. The method for preparing a tetracycline photocatalyst as described in claim 1, characterized in that: The high-pressure reactor is lined with polytetrafluoroethylene.