Modified titanium dioxide photocatalyst as well as preparation method and application thereof

Abstract

The invention relates to the technical field of photocatalysts, in particular to a modified titanium dioxide photocatalyst and a preparation method and application thereof.The preparation method includes the following steps that firstly, a titanate solution and first absolute ethyl alcohol are mixed to prepare a solution A; mixing second absolute ethyl alcohol, glacial acetic acid and water to prepare a solution B; 2, adding the solution B into the solution A, and stirring and mixing to obtain a mixed solution; 3, down feather is added into the mixed solution obtained in the step 2, a high-temperature reaction is conducted in a closed environment, a product is washed and dried, then the modified titanium dioxide photocatalyst is obtained, and the high-temperature reaction temperature ranges from 120 DEG C to 180 DEG C. The method is simple in preparation process, high in efficiency and low in equipment requirement, and the duck down fibers are used as raw materials of modified titanium dioxide, so that the method has the characteristics of rich resources, no toxicity, greenness, reproducibility and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of photocatalysts, and in particular to a modified titanium dioxide photocatalyst, a preparation method thereof, and an application thereof. Background Art

[0002] Semiconductor photocatalysis is an environmentally friendly technology for effectively degrading pollutants. As a new type of inorganic semiconductor material, TiO2 nanomaterials have attracted much attention due to their photocatalytic activity, non-toxicity, and biocompatibility. However, some inevitable disadvantages of titanium dioxide cannot be ignored, such as being active only in the ultraviolet range, resulting in low photocatalytic performance in the visible light range and a high recombination rate of photo-generated electrons and holes. Currently, in order to effectively utilize sunlight and further improve the photocatalytic performance of titanium dioxide, researchers have improved the structure of TiO2 by doping transition metals (high cost, and some toxic elements are prone to cause secondary pollution), semiconductor compounding (difficult to control the preparation process), non-metal element modification, etc., thereby expanding its light response range and reducing the carrier recombination rate. Therefore, modification methods such as metal element doping and semiconductor compounding have high costs, and in some environments, the photocatalyst undergoes photocorrosion during the visible light catalytic process, affecting the durability of the photocatalytic performance.

[0003] Specifically, non-metal doping with elements such as nitrogen, carbon, sulfur, fluorine, or iodine has been proven to effectively reduce the band gap and improve the photocatalytic activity. Doping TiO2 with non-metal elements will change its electronic band structure, reduce the band gap energy, and enhance the responsiveness to visible light. As a widely available, low-cost, and renewable natural material, biomass materials contain abundant non-metal elements. Compared with organic materials such as urea used as a nitrogen source to modify titanium dioxide, using renewable materials conforms to the principles of green chemistry, emphasizing that the process design has the least impact on the environment while maximizing efficiency. Currently, the preparation process of the modified titanium dioxide photocatalyst is complex, cannot be synthesized in one step, and has a high material cost.

[0004] As in the prior art, a waste textile modified titanium dioxide material, a preparation method thereof, and an application thereof disclosed in CN118164528A have a complex preparation process and a long time consumption (successively through solvothermal reaction and calcination). The feather down carbonized modified titanium dioxide aerogel photocatalyst, preparation, and application disclosed in CN115999583A prepares a feather down modified titanium dioxide catalyst by a calcination method. The tubular furnace equipment used has the problem of excessive energy consumption during operation, low degradation efficiency of dyes, and a long treatment time. The degradation efficiency of methyl orange under visible light after 18 h is 72%. And through research, its degradation is mainly adsorption degradation, rather than photocatalytic degradation.

[0005] Therefore, it is an urgent problem to be solved to realize that the modified titanium dioxide photocatalyst has the characteristics of simple preparation process, good degradation effect, and visible light response range. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to provide a modified titanium dioxide photocatalyst, its preparation method and application, so as to simplify the preparation process, reduce the requirements for equipment, and have a good degradation effect.

[0007] Based on the above purpose, the present invention provides a preparation method of a modified titanium dioxide photocatalyst, which includes the following steps:

[0008] Step 1: Mix the titanate solution with the first absolute ethanol to prepare solution A; mix the second absolute ethanol, glacial acetic acid and water to prepare solution B;

[0009] Step 2: Add solution B to solution A and stir to mix to obtain a mixed solution;

[0010] Step 3: Add down feathers to the mixed solution obtained in Step 2, and obtain the modified titanium dioxide photocatalyst after high-temperature reaction in a closed environment, product washing, and drying. Among them, the temperature of the high-temperature reaction is 120-180°C.

[0011] In Step 1, the titanate solution is tetrabutyl titanate solution, and the volume ratio of the tetrabutyl titanate solution to the first absolute ethanol is 3:4.

[0012] In Step 1, the volume ratio of the second absolute ethanol to glacial acetic acid in solution B is 6:5, and the volume ratio of tetrabutyl titanate to glacial acetic acid is 3:2.

[0013] The volume ratio of solution A to solution B is 3:2.

[0014] In Step 3, the mass-volume ratio of the down feathers to the mixed solution is 0.4-0.8 g:63 mL.

[0015] In Step 3, the time of the high-temperature reaction is 11-13 h.

[0016] In Step 3, the drying is carried out in an oven, and the drying temperature is 60°C.

[0017] The present invention also provides a modified titanium dioxide photocatalyst prepared by using the above preparation method.

[0018] The present invention also provides the application of the modified titanium dioxide photocatalyst in the photocatalytic degradation of dye wastewater.

[0019] As the most abundant natural protein fiber in nature, the basic structure of down fiber (DF) is a primary structure polypeptide chain formed by the combination of multiple amino acids and a secondary structure α-helix caused by hydrogen bonds and disulfide bonds (-S-S-) in the polypeptide chain. It contains non-metallic elements such as C, N, P, and S, enabling multi-element doping modification.

[0020] Advantages of the present invention: The modified titanium dioxide from down prepared by the solvothermal method in the present invention can efficiently degrade target pollutants within 3 hours, which not only significantly overcomes the drawback of long treatment time in the prior art but also provides a more efficient and energy-saving solution for practical applications in related fields. The preparation process of the present invention is simple, highly efficient, and requires low equipment. This method uses waste down as the raw material for modified titanium dioxide, featuring rich resources, non-toxicity, greenness, and renewability. The preparation process realizes the high-value utilization of down fiber, conforming to the principle of green environmental protection and having good practical application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] To more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only those of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0022] Figure 1 It is an optical comparison diagram of the samples prepared in Example 1 and Example 3 of the present invention; among them, a is the optical diagram of Example 1, and b is the optical diagram of Example 3;

[0023] Figure 2 It is a scanning electron microscope image of the sample prepared in Example 3 of the present invention;

[0024] Figure 3 It is an element mapping test result diagram of the sample prepared in Example 3 of the present invention;

[0025] Figure 4 It is an ultraviolet-visible diffuse reflection spectrum diagram of the samples in Example 1 and Example 3 of the present invention;

[0026] Figure 5 It is an ESR spectrum of the sample prepared in Example 3 of the present invention;

[0027] Figure 6 It is a photocatalytic degradation efficiency diagram of the samples prepared in Examples 1-4 of the present invention for methyl orange;

[0028] Figure 7 It is a before-and-after effect diagram of the photocatalytic degradation of methyl orange by the sample prepared in Example 3 of the present invention;

[0029] Figure 8Photocatalytic degradation effect diagrams of DF-TiO2 samples prepared in Comparative Example 1 and Example 4 on methyl orange;

[0030] Figure 9 Adsorption and photocatalytic performance test results of Comparative Example 1 under light and dark conditions. Detailed implementation manners

[0031] To make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to specific embodiments.

[0032] It should be noted that unless otherwise defined, the technical terms or scientific terms used in the present invention should have the ordinary meanings understood by those of ordinary skill in the field to which the present invention belongs. The "first", "second" and similar terms used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. The terms such as "comprising" or "including" mean that the elements or objects appearing before this term cover the elements or objects listed after this term and their equivalents, without excluding other elements or objects.

[0033] Example 1

[0034] In this example, solution A was first prepared: 18 mL of tetrabutyl titanate solution and 24 mL of absolute ethanol solution were measured and added to a beaker, and stirred for 0.5 h.

[0035] Then solution B was prepared: 12 mL of absolute ethanol solution, 10 mL of glacial acetic acid solution, and 6 mL of deionized water were measured and added to beakers respectively, and stirred for 0.5 h.

[0036] Solution B was added to solution A at a slow rate, and stirring was continued for 10 min to obtain a mixed solution.

[0037] Subsequently, the mixed solution was transferred to a high-pressure reactor and placed in an oven. The parameters were set as follows: the temperature was set to 150 °C and the time was 12 h. After the reaction was completed, the product was washed several times with deionized water and then placed in an oven to dry, and finally a titanium dioxide photocatalyst (TiO2) was obtained.

[0038] Example 2

[0039] In this example, solution A was first prepared: 18 mL of tetrabutyl titanate solution and 24 mL of absolute ethanol solution were measured and added to a beaker, and stirred for 0.5 h.

[0040] Then solution B was prepared: 12 mL of absolute ethanol solution, 10 mL of glacial acetic acid solution, and 6 mL of deionized water were measured and added to beakers respectively, and stirred for 0.5 h.

[0041] Add solution B to solution A at a slow rate and continue stirring for 10 min to obtain a mixed solution.

[0042] Subsequently, weigh 0.4 g of down and add it to the mixed solution. Then transfer it to a high-pressure reactor and place it in an oven. The parameters are set as follows: the temperature is set to 150 °C and the time is 12 h. After the reaction is completed, wash the product with deionized water several times and then dry it in the oven to finally obtain the down-modified titanium dioxide photocatalyst (DF-TiO2).

[0043] Example 3

[0044] In this example, first prepare solution A: Measure 18 mL of tetrabutyl titanate solution and 24 mL of absolute ethanol solution and add them to a beaker, and stir for 0.5 h.

[0045] Then prepare solution B: Measure 12 mL of absolute ethanol solution, 10 mL of glacial acetic acid solution, and 6 mL of deionized water, and add them to beakers respectively and stir for 0.5 h.

[0046] Add solution B to solution A at a slow rate and continue stirring for 10 min to obtain a mixed solution.

[0047] Subsequently, weigh 0.6 g of down and add it to the mixed solution. Then transfer it to a high-pressure reactor and place it in an oven. The parameters are set as follows: the temperature is set to 150 °C and the time is 12 h. After the reaction is completed, wash the product with deionized water several times and then dry it in the oven to finally obtain the down-modified titanium dioxide photocatalyst (DF-TiO2).

[0048] Example 4

[0049] In this example, first prepare solution A: Measure 18 mL of tetrabutyl titanate solution and 24 mL of absolute ethanol solution and add them to a beaker, and stir for 0.5 h.

[0050] Then prepare solution B: Measure 12 mL of absolute ethanol solution, 10 mL of glacial acetic acid solution, and 6 mL of deionized water, and add them to beakers respectively and stir for 0.5 h.

[0051] Add solution B to solution A at a slow rate and continue stirring for 10 min to obtain a mixed solution.

[0052] Subsequently, weigh 0.8 g of down and add it to the mixed solution. Then transfer it to a high-pressure reactor and place it in an oven. The parameters are set as follows: the temperature is set to 150 °C and the time is 12 h. After the reaction is completed, wash the product with deionized water several times and then dry it in the oven to finally obtain the down-modified titanium dioxide photocatalyst (DF-TiO2).

[0053] Comparative Example 1

[0054] In this comparative example, solution A was first prepared: 18 mL of tetrabutyl titanate solution and 24 mL of anhydrous ethanol solution were added to a beaker and stirred for 0.5 h.

[0055] Then prepare solution B: measure 12 mL of anhydrous ethanol solution, 10 mL of glacial acetic acid solution, and 6 mL of deionized water, add them into a beaker respectively, and stir for 0.5 h.

[0056] Solution B was slowly added to solution A and stirring was continued for 10 min to obtain a mixed solution.

[0057] The sol was allowed to stand for a period of time, 0.8 g of down was added and stirred thoroughly, and the sol was placed in an oven for drying. After drying, the sol was placed in a tubular furnace for calcination, and the temperature was increased to 500 °C at a rate of 5 °C / min. The sol was kept at 500 °C for 2 h, and the sol was taken out after cooling to obtain a calcined down-modified titanium dioxide photocatalyst.

[0058] Figure 9 This is the adsorption and photocatalytic performance test result diagram of Comparative Example 1. It can be seen from the figure that after 1 hour of reaction, the adsorption efficiency of methyl orange of DF-TiO2 treated by calcination method reached 25.21% under lightless conditions, while under light conditions, its photocatalytic efficiency of methyl orange was 25.60%. Comparison of these two data shows that the photocatalytic efficiency under light conditions is slightly improved compared with the adsorption efficiency under lightless conditions, which proves that the photocatalytic degradation effect of DF-TiO2 prepared by calcination method on methyl orange is not significant under light conditions. Therefore, it can be inferred that the degradation effect of this sample on methyl orange is basically due to its own adsorption effect, rather than photocatalytic effect.

[0059] Figure 1 This is an optical comparison diagram of the TiO2 sample prepared in Example 1 and the DF-TiO2 sample prepared in Example 3. TiO2 is a white powder, and the DF-TiO2 sample after down modification is yellow.

[0060] The scanning electron microscope image of the sample photocatalyst sample prepared in Example 3 is as follows: Figure 2 As shown, it has good dispersibility and the morphology is round particles.

[0061] Figure 3 The EDS element scanning image of the DF-TiO2 sample prepared in Example 3 shows uniform distribution of non-metallic elements such as C, N, P, and S, indicating that the down was successfully modified and doped with titanium dioxide.

[0062] Figure 4For the UV-visible diffuse reflectance spectra of the samples in Example 1 and Example 3 within the wavelength range of 200 - 800 nm, it can be seen that in the range of 200 - 400 nm, DF-TiO2 exhibits higher light absorbance compared to TiO2. In the range of 400 - 800 nm, TiO2 basically does not absorb visible light, while the wavelength of DF-TiO2 is significantly red-shifted into the visible light region, enhancing its absorption ability of visible light.

[0063] Figure 5 Figure 4 shows the ESR spectrum of the DF-TiO2 sample prepared in Example 3. It is found from the figure that no free radical signal of ·OH appears under dark conditions, and no obvious free radical signal appears after 5 min of illumination. For ·O2 - no free radical signal appears under dark conditions either, while an obvious characteristic peak corresponding to ·O2 - appears after 5 min of illumination. Under dark conditions, the characteristic peak of the scavenger TEMPO itself can be seen. After 5 min of illumination, the characteristic peak weakens due to the combination of TEMPO and h + . This fully proves that ·O2 - , ·h + are the main reactive species for the degradation of dyes by DF-TiO2.

[0064] The present invention also provides an application of modified titanium dioxide with down in photocatalysis.

[0065] Photocatalytic degradation test of methyl orange.

[0066] Test method:

[0067] Add 100 mg of photocatalyst to 50 mL of methyl orange solution (20 mg / L). First, stir for 60 min under dark conditions to reach the adsorption-desorption equilibrium, and then irradiate under the power density of one sunlight. During the photocatalytic process, take out the dye solution for centrifugation at regular intervals, and use a UV-visible spectrophotometer to test the concentration change of the dye solution for the supernatant.

[0068] Test results:

[0069] Figure 6 Figure 5 shows the photocatalytic degradation efficiency of methyl orange for Examples 1 - 4. It can be seen from the figure that after irradiating for 3 h under the power density of one sunlight, the degradation efficiency of methyl orange by Example 1 is 63.6%. After adding down to the samples of Examples 2 to 3, the degradation efficiency of the optimal sample, Example 3, for methyl orange is 96.39%.

[0070] Figure 7Photocatalytic degradation effect diagram of the DF-TiO2 sample prepared in Example 3 on methyl orange. It can be seen from the figure that after 3 h of photocatalytic reaction, the color of the methyl orange solution changes from orange to nearly colorless solution, proving that the DF-TiO2 sample has a significant photocatalytic degradation effect on methyl orange.

[0071] Figure 8 Photocatalytic degradation effect diagram of the DF-TiO2 samples prepared in Comparative Example 1 and Example 4 on methyl orange. It can be seen from the figure that after 3 h of photocatalytic reaction, the photocatalytic efficiency of DF-TiO2 treated by the calcination method is 34.72%, while the photocatalytic efficiency of DF-TiO2 prepared by the solvothermal method is 95.94%, proving that the photocatalytic degradation effect of the DF-TiO2 sample prepared by the solvothermal method is significantly improved compared with that of the DF-TiO2 sample prepared by the calcination method.

[0072] Those of ordinary skill in the art should understand that: the discussion of any above embodiment is only exemplary and is not intended to imply that the scope of the present invention is limited to these examples; under the idea of the present invention, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations in different aspects of the present invention as described above, which are not provided in detail for the sake of brevity. Any omission, modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A preparation method of a modified titanium dioxide photocatalyst, characterized in that, It includes the following steps: Step 1: Mix the titanate solution with the first absolute ethanol to prepare solution A; mix the second absolute ethanol, glacial acetic acid and water to prepare solution B; Step 2: Add solution B to solution A and stir to mix to obtain a mixed solution; Step 3: Add the down feathers to the mixed solution described in Step 2, and obtain a modified titanium dioxide photocatalyst after high-temperature reaction in a closed environment, product washing and drying, wherein the temperature of the high-temperature reaction is 120-180 °C.

2. The preparation method of the modified titanium dioxide photocatalyst according to claim 1, characterized in that, In Step 1, the titanate solution is tetrabutyl titanate solution, and the volume ratio of the tetrabutyl titanate solution to the first absolute ethanol is 3:

4.

3. The preparation method of the modified titanium dioxide photocatalyst according to claim 2, characterized in that, In Step 1, the volume ratio of the second absolute ethanol to glacial acetic acid in solution B is 6:5, and the volume ratio of tetrabutyl titanate to glacial acetic acid is 3:

2.

4. The preparation method of the modified titanium dioxide photocatalyst according to claim 1, characterized in that, The volume ratio of solution A to solution B is 3:

2.

5. The preparation method of the modified titanium dioxide photocatalyst according to claim 1, characterized in that, In Step 3, the mass-volume ratio of the down feathers to the mixed solution is 0.4-0.8 g:63 mL.

6. The preparation method of the modified titanium dioxide photocatalyst according to claim 1, wherein, In Step 3, the time of the high-temperature reaction is 11-13 h.

7. The preparation method of the modified titanium dioxide photocatalyst according to claim 1, wherein In Step 3, the drying is drying in an oven, and the drying temperature is 60 °C.

8. A modified titanium dioxide photocatalyst, characterized in that, Prepared by the preparation method according to any one of claims 1-7.

9. Application of the modified titanium dioxide photocatalyst according to claim 8 in photocatalytic degradation of dye wastewater.

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