Preparation method and application of up-conversion composite photocatalyst based on binary doping

Abstract

The invention discloses a preparation method and application of an up-conversion composite photocatalyst based on binary doping, and relates to the field of preparation of rare earth up-conversion agent composite photocatalysts. The invention aims to solve the technical problems of insufficient sunlight utilization rate and low degradation rate under near-infrared light in the existing photocatalytic system. According to the method, Yb < 3 + > / Tm < 3 + > is co-doped with the tubular up-conversion photocatalyst. According to the invention, Yb < 3 + > / Tm < 3 + > is co-doped with NaYF4 (at) g-C3N4, so that the response capability of the catalyst to a spectrum is widened, the utilization rate of light energy is further improved, and the degradation performance of the catalyst is enhanced. The prepared up-conversion composite photocatalyst is used for treating antibiotics in sewage.

Description

Technical Field

[0001] The invention relates to the field of preparation of rare earth up-converter composite photocatalyst. Background Art

[0002] Upconversion photocatalysts have attracted much attention in the field of environmental pollution control due to their green and environmentally friendly characteristics, low energy consumption, simple operation and advantages of not causing waste of resources. In recent years, they have developed rapidly in theory and practical application. The factors that affect the performance of upconversion photocatalysts mainly include band gap, wavelength of light, catalyst material structure and sensitizer. Upconversion materials based on the anti-Stokes luminescence mechanism can absorb low-energy photons and radiate specific types of photons with shorter wavelengths, thereby improving the utilization rate of sunlight by UC photocatalysts. However, UC photocatalysts still face the problem of low UC utilization rate, and the degradation efficiency of the obtained photocatalysts under near-infrared light is difficult to meet the demand. Therefore, it is urgent to find an effective strategy to improve the degradation efficiency of UC photocatalysts. Summary of the invention

[0003] In order to solve the technical problems of insufficient sunlight utilization and low degradation rate under near-infrared light in the existing photocatalytic system, the present invention provides a preparation method and application of a binary doped upconversion composite photocatalyst.

[0004] A preparation method based on binary doping upconversion composite photocatalyst is specifically carried out according to the following steps:

[0005] 1. Dissolve 0.9g of sodium hydroxide in pure water, add 15mL of oleic acid and 9mL of anhydrous ethanol, and stir evenly at a temperature of 30-32°C to obtain a mixed solution A;

[0006] 2. Dissolve 0.8mmol Y(NO3)3·6H2O in 5mL distilled water, then add 0.19mmol Yb(NO3)3·6H2O and 0.01mmol Tm(NO3)3·5H2O, stir evenly at 30-32℃ to obtain mixed solution B;

[0007] 3. Mix the mixed solution A obtained in step 1 and the mixed solution B obtained in step 2, and stir evenly at a temperature of 30 to 32° C. to obtain a suspension;

[0008] 4. Add 0.168 g NaF solid powder to the suspension obtained in step 3, stir at 30°C for 30-35 min, then transfer to a high-pressure hydrothermal reactor, control the temperature to 180°C and heat for 24 h to obtain an emulsion; naturally cool to room temperature, collect samples; then wash and centrifuge with cyclohexane, anhydrous ethanol and distilled water in turn, dry the product obtained by centrifugation, and grind it in an agate mortar to obtain a white powder;

[0009] 5. Dissolve 0.2 g of melamine in 20 mL of pure water to obtain a melamine solution, dissolve 0.06 g of cyanuric acid in 40 mL of pure water to obtain a cyanuric acid solution, then add the cyanuric acid solution to the melamine solution, stir for 60 to 65 minutes, then transfer to a high-pressure hydrothermal reactor, heat at 180° C. for 10 hours, then naturally cool to room temperature, centrifuge and filter, and dry to obtain a white sponge-like block;

[0010] 6. Place the white sponge-like block obtained in step 5 into a porcelain boat, and heat at 500° C. for 90 to 92 minutes under a nitrogen atmosphere to obtain a tubular light yellow powder;

[0011] 7. The white powder obtained in step 4 and the tubular light yellow powder obtained in step 6 are placed in anhydrous ethanol at a mass ratio of 3:2 and ultrasonically treated for 1 hour, then the rotation speed is controlled to 500-600 r / min and stirred for 24 hours, and centrifuged and dried to obtain a composite material, that is, the preparation of the binary doped upconversion composite photocatalyst is completed.

[0012] The binary doping upconversion composite photocatalyst is used as a catalyst for treating antibiotics in sewage.

[0013] Yb used in the present invention 3+ / Tm 3+ Co-doping can make the composite catalyst emit blue-violet light under the excitation of near-infrared light, which can effectively improve the utilization rate of near-infrared light in sunlight, thereby increasing the degradation rate of tetracycline in wastewater.

[0014] Beneficial effects of the present invention:

[0015] The tubular binary composite up-conversion photocatalyst of the present invention is easy to operate, low in cost and low in production risk.

[0016] Through rare earth Yb 3+ / Tm 3+ Co-doping broadens the catalyst's ability to respond to the spectrum, thereby improving the utilization rate of light energy and enhancing its degradation performance.

[0017] The present invention synthesizes a Yb by hydrothermal method. 3+ / Tm 3+ Co-doped binary composite upconversion photocatalyst, where Tm 3 + With blue upconversion luminescence, Yb 3+ As a highly effective sensitizer, 2 F 5 / 2The energy level can show a larger absorption cross-section, has a stronger absorption capacity for near-infrared light, broadens the spectral absorption range, improves light utilization, and further improves the performance of upconversion photocatalysts.

[0018] The tubular binary composite up-conversion photocatalyst prepared by the invention is used for treating antibiotics in sewage. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a scanning electron microscope photo of a binary doped upconversion composite photocatalyst obtained in the example;

[0020] Figure 2 This is an XRD spectrum of a binary doped upconversion composite photocatalyst obtained in the example;

[0021] Figure 3 This is a graph showing the degradation efficiency of a binary doped upconversion composite photocatalyst for tetracycline at a concentration of 20 mg / L prepared in the example. DETAILED DESCRIPTION

[0022] Specific implementation method 1: This implementation method is a preparation method based on binary doping upconversion composite photocatalyst, which is specifically carried out in the following steps:

[0023] 1. Dissolve 0.9g of sodium hydroxide in pure water, add 15mL of oleic acid and 9mL of anhydrous ethanol, and stir evenly at a temperature of 30-32°C to obtain a mixed solution A;

[0024] 2. Dissolve 0.8mmol Y(NO3)3·6H2O in 5mL distilled water, then add 0.19mmol Yb(NO3)3·6H2O and 0.01mmol Tm(NO3)3·5H2O, stir evenly at 30-32℃ to obtain mixed solution B;

[0025] 3. Mix the mixed solution A obtained in step 1 and the mixed solution B obtained in step 2, and stir evenly at a temperature of 30 to 32° C. to obtain a suspension;

[0026] 4. Add 0.168 g NaF solid powder to the suspension obtained in step 3, stir at 30°C for 30-35 min, then transfer to a high-pressure hydrothermal reactor, control the temperature to 180°C and heat for 24 h to obtain an emulsion; naturally cool to room temperature, collect samples; then wash and centrifuge with cyclohexane, anhydrous ethanol and distilled water in turn, dry the product obtained by centrifugation, and grind it in an agate mortar to obtain a white powder;

[0027] 5. Dissolve 0.2 g of melamine in 20 mL of pure water to obtain a melamine solution, dissolve 0.06 g of cyanuric acid in 40 mL of pure water to obtain a cyanuric acid solution, then add the cyanuric acid solution to the melamine solution, stir for 60 to 65 minutes, then transfer to a high-pressure hydrothermal reactor, heat at 180° C. for 10 hours, then naturally cool to room temperature, centrifuge and filter, and dry to obtain a white sponge-like block;

[0028] 6. Place the white sponge-like block obtained in step 5 into a porcelain boat, and heat at 500° C. for 90 to 92 minutes under a nitrogen atmosphere to obtain a tubular light yellow powder;

[0029] 7. The white powder obtained in step 4 and the tubular light yellow powder obtained in step 6 are placed in anhydrous ethanol at a mass ratio of 3:2 and ultrasonically treated for 1 hour, then the rotation speed is controlled to 500-600 r / min and stirred for 24 hours, and centrifuged and dried to obtain a composite material, that is, the preparation of the binary doped upconversion composite photocatalyst is completed.

[0030] Specific implementation method 2: This implementation method is different from the specific implementation method 1 in that the stirring time in step 1 is controlled to be 20 to 25 minutes. The rest is the same as the specific implementation method 1.

[0031] Specific implementation method 3: This implementation method is different from specific implementation method 1 or 2 in that: step 3 controls the stirring for 10 to 15 minutes. The rest is the same as specific implementation method 1 or 2.

[0032] Specific embodiment 4: This embodiment differs from specific embodiments 1 to 3 in that the capacity of the high-pressure hydrothermal reactor in step 4 is 100 mL. Other aspects are the same as those of specific embodiments 1 to 3.

[0033] Specific implementation method 5: This implementation method is different from specific implementation methods 1 to 4 in that: in step 4, the stirring speed is controlled to be 500-600 r / min. The rest is the same as specific implementation methods 1 to 4.

[0034] Specific implementation method 6: This implementation method is different from specific implementation methods 1 to 5 in that the drying temperature in step 4 is controlled to be 60-80° C. The rest is the same as specific implementation methods 1 to 5.

[0035] Specific implementation method 7: This implementation method is different from specific implementation methods 1 to 6 in that the rotation speed of step 5 centrifugal filtration is controlled to be 4000 r / min. The rest is the same as specific implementation methods 1 to 6.

[0036] Specific embodiment 8: This embodiment is different from specific embodiments 1 to 7 in that the drying temperature in step 5 is controlled to be 60-65° C. The rest is the same as specific embodiments 1 to 7.

[0037] Specific embodiment 9: This embodiment is different from specific embodiments 1 to 8 in that the stirring speed in step 7 is controlled to be 550 / min. The rest is the same as specific embodiments 1 to 8.

[0038] Specific implementation method ten: This implementation method is an application of a binary doping upconversion composite photocatalyst, wherein the binary doping upconversion composite photocatalyst is used as a catalyst to treat antibiotics in sewage.

[0039] The content of the present invention is not limited to the content of the above-mentioned embodiments. The combination of one or several specific embodiments can also achieve the purpose of the invention.

[0040] Example:

[0041] This embodiment provides a method for preparing a binary doping upconversion composite photocatalyst, which is specifically carried out in the following steps:

[0042] 1. Dissolve 0.9g of sodium hydroxide in pure water, add 15mL of oleic acid and 9mL of anhydrous ethanol, and stir at 30°C for 20min to obtain a mixed solution A;

[0043] 2. Dissolve 0.8mmol Y(NO3)3·6H2O in 5mL distilled water, then add 0.19mmol Yb(NO3)3·6H2O and 0.01mmol Tm(NO3)3·5H2O, stir evenly at 30℃ to obtain mixed solution B;

[0044] 3. Mix the mixed solution A obtained in step 1 and the mixed solution B obtained in step 2, and stir at 30° C. for 10 min to obtain a suspension;

[0045] 4. Add 0.168g NaF solid powder to the suspension obtained in step 3, stir for 30min at 30℃, then transfer to a 100mL high-pressure hydrothermal reactor, control the temperature to 180℃ and heat for 24h to obtain an emulsion; cool naturally to room temperature, collect samples; then wash and centrifuge with cyclohexane, anhydrous ethanol and distilled water in sequence, dry the product obtained by centrifugation at 60℃, and grind in an agate mortar to obtain a white powder, i.e., a binary doping upconverter;

[0046] 5. Dissolve 0.2 g of melamine in 20 mL of pure water to obtain a melamine solution, dissolve 0.06 g of cyanuric acid in 40 mL of pure water to obtain a cyanuric acid solution, then add the cyanuric acid solution to the melamine solution, stir for 60 min, then transfer to a high-pressure hydrothermal reactor, heat at 180 ° C for 10 h, then naturally cool to room temperature, centrifuge and filter, and dry at 60 ° C to obtain a white sponge-like block;

[0047] 6. Place the white sponge-like block obtained in step 5 into a porcelain boat, and heat it at 500° C. for 90 min under a nitrogen atmosphere to obtain a tubular light yellow powder;

[0048] 7. The white powder obtained in step 4 and the tubular light yellow powder obtained in step 6 are placed in anhydrous ethanol at a mass ratio of 3:2 and ultrasonically treated for 1 hour, then the rotation speed is controlled to 500-600 r / min and stirred for 24 hours, and centrifuged and dried to obtain a light yellow powder composite material, that is, the preparation of the binary doped upconversion composite photocatalyst is completed.

[0049] The scanning electron microscope photo of a binary doped upconversion composite photocatalyst obtained in this example is shown in FIG. Figure 1 As shown; the XRD spectrum of a binary doped upconversion composite photocatalyst obtained in this embodiment is as shown Figure 2 As shown; the degradation efficiency curve of a binary doped upconversion composite photocatalyst for tetracycline at a concentration of 20 mg / L obtained in this embodiment is shown in Figure 3 As shown, it is verified that the efficiency of tetracycline degradation by the binary doped upconversion composite photocatalyst obtained in this embodiment under near-infrared light irradiation for 2 hours is 49.31%.

[0050] Yb 3+ / Tm 3+ The co-doped tubular upconversion photocatalyst achieves a high degradation efficiency of tetracycline under near-infrared light, proving the application of the present invention in the field of treating antibiotics.

Claims

1. A method for preparing a binary doped upconversion composite photocatalyst, characterized in that The method is specifically carried out in the following steps:

1. Dissolve 0.9g of sodium hydroxide in pure water, add 15mL of oleic acid and 9mL of anhydrous ethanol, and stir evenly at a temperature of 30-32°C to obtain a mixed solution A; 2. Dissolve 0.8mmol Y(NO3)3·6H2O in 5mL distilled water, then add 0.19mmol Yb(NO3)3·6H2O and 0.01mmol Tm(NO3)3·5H2O, stir evenly at 30-32℃ to obtain mixed solution B; 3. Mix the mixed solution A obtained in step 1 and the mixed solution B obtained in step 2, and stir evenly at a temperature of 30 to 32° C. to obtain a suspension; 4. Add 0.168 g NaF solid powder to the suspension obtained in step 3, stir at 30°C for 30-35 min, then transfer to a high-pressure hydrothermal reactor, control the temperature to 180°C and heat for 24 h to obtain an emulsion; naturally cool to room temperature, collect samples; then wash and centrifuge with cyclohexane, anhydrous ethanol and distilled water in turn, dry the product obtained by centrifugation, and grind it in an agate mortar to obtain a white powder; 5. Dissolve 0.2 g of melamine in 20 mL of pure water to obtain a melamine solution, dissolve 0.06 g of cyanuric acid in 40 mL of pure water to obtain a cyanuric acid solution, then add the cyanuric acid solution to the melamine solution, stir for 60 to 65 minutes, then transfer to a high-pressure hydrothermal reactor, heat at 180° C. for 10 hours, then naturally cool to room temperature, centrifuge and filter, and dry to obtain a white sponge-like block; 6. Place the white sponge-like block obtained in step 5 into a porcelain boat, and heat at 500° C. for 90 to 92 minutes under a nitrogen atmosphere to obtain a tubular light yellow powder; 7. The white powder obtained in step 4 and the tubular light yellow powder obtained in step 6 are placed in anhydrous ethanol at a mass ratio of 3:2 and ultrasonically treated for 1 hour, then the rotation speed is controlled to 500-600 r / min and stirred for 24 hours, and centrifuged and dried to obtain a composite material, that is, the preparation of the binary doped upconversion composite photocatalyst is completed.

2. The method for preparing a binary doping upconversion composite photocatalyst according to claim 1, characterized in that Step 1: Control the stirring time to 20 to 25 minutes.

3. The method for preparing a binary doping upconversion composite photocatalyst according to claim 1, characterized in that Step 3: Control the stirring for 10 to 15 minutes.

4. The method for preparing a binary doping upconversion composite photocatalyst according to claim 1, characterized in that The capacity of the high-pressure hydrothermal reactor in step 4 is 100 mL.

5. The method for preparing a binary doping upconversion composite photocatalyst according to claim 1, characterized in that Step 4: Control the stirring speed to 500-600 r / min.

6. The method for preparing a binary doping upconversion composite photocatalyst according to claim 1, characterized in that Step 4: Control the drying temperature to 60-80°C.

7. The method for preparing a binary doping upconversion composite photocatalyst according to claim 1, characterized in that Step 5: Centrifugal filtration, control the rotation speed to 4000 r / min.

8. The method for preparing a binary doping upconversion composite photocatalyst according to claim 1, characterized in that Step 5: Control the drying temperature to 60-65°C.

9. The method for preparing a binary doping upconversion composite photocatalyst according to claim 1, characterized in that Step 7: Control the stirring speed to 550 r / min.

10. The use of a binary doped upconversion composite photocatalyst as claimed in claim 1, characterized in that The binary doping upconversion composite photocatalyst is used as a catalyst for treating antibiotics in sewage.

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