A method for preparing a composite catalyst and use thereof
By preparing a composite catalyst with Ag nanoparticles deposited on spiky Fe2O3, the problems of small specific surface area and high recombination rate of photogenerated carriers in semiconductor materials were solved, achieving a highly efficient wastewater treatment effect.
Patent Information
- Application Number
- CN202311715773.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-13
- Publication Date
- 2026-03-20
- Estimated Expiration
- 2043-12-13
AI Technical Summary
The small specific surface area and high recombination rate of photogenerated carriers in existing semiconductor materials result in low degradation efficiency, which limits their application in wastewater treatment.
A composite catalyst was prepared by depositing Ag nanoparticles on spiky Fe2O3, which was grown on carbonized rapeseed pollen, and by hydrothermal treatment and photodeposition methods, forming a catalyst with a large specific surface area and a low photogenerated carrier recombination rate.
It significantly improved the material's cycle life and photocatalytic performance, increased the number of reactive sites, enhanced the pollutant treatment effect, strengthened the catalyst's stability and mechanical strength, and improved the light absorption efficiency.
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Figure CN117696072B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of water treatment, in particular to a preparation method of a composite material catalyst and application thereof. BACKGROUND
[0002] At present, the printing and dyeing industry is developing rapidly, and the treatment of printing and dyeing wastewater still relies on physical adsorption treatment, which cannot be completely treated, and the printing and dyeing wastewater can be treated into non-toxic small molecular compounds by a semiconductor photocatalytic method, which can effectively reduce the pollution to the environment; but the traditional semiconductor material has a small specific surface area and a high recombination rate of photo-generated carriers, resulting in a low degradation efficiency, which limits its application in wastewater treatment.
[0003] Therefore, the present application aims to provide a preparation method of a composite material catalyst and application thereof to improve the shortcomings of the existing materials. SUMMARY
[0004] In view of the shortcomings of the prior art, the present application provides a preparation method of a composite material catalyst and application thereof, which solves the problem of the current semiconductor material having a small specific surface area and a high recombination rate of photo-generated carriers, resulting in a low degradation efficiency and limiting its application effect in wastewater treatment.
[0005] To achieve the above object, the present application is implemented by the following technical scheme: a preparation method of a composite material catalyst, the catalyst comprising Ag nanoparticles, Fe2O3 with a thorn-like structure and carbonized rape pollen, the Ag nanoparticles being deposited on the Fe2O3 with a thorn-like structure, and the Fe2O3 with a thorn-like structure being grown on the carbonized rape pollen, comprising the following preparation steps:
[0006] S1, preparation of carbonized rape pollen base C:
[0007] The rape pollen is soaked in anhydrous ethanol and subjected to ultrasonic treatment, then soaked in a mixed solution of anhydrous ethanol and formalin, filtered, poured into concentrated sulfuric acid and stirred, and then suction filtered, and dried to obtain carbonized rape pollen;
[0008] S2, preparation of thorn-like Fe2O3 / C:
[0009] The carbonized rape pollen is placed in a mixed solution of iron nitrate nonahydrate, sodium fluoride, cationic surfactant and NaOH, sealed and subjected to hydrothermal treatment, and the material after hydrothermal treatment is calcined to obtain thorn-like Fe2O3 / C material;
[0010] S3, preparation of Ag@Fe2O3 / C:
[0011] The thorn-like Fe2O3 / C is configured into a mixed solution, polyethylene glycol solution is stirred into the mixed solution, AgNO3 is added, photodeposition is carried out by using a xenon lamp, a precipitate is obtained, the precipitate is dried by centrifugation, and the precipitate is ground into powder by using a mortar to obtain a powder sample.
[0012] Preferably, in the S1 step, the mass ratio of rapeseed pollen to the mixed solution of anhydrous ethanol is 1:10; the volume ratio of the mixed solution of anhydrous ethanol and formaldehyde used is between 0.5 and 2; and the filtered pollen sample is poured into 12M concentrated sulfuric acid and soaked at 75-80 DEG C in an oil bath for 4h.
[0013] Preferably, in the S1 step, the solution after soaking in concentrated sulfuric acid is suction filtered, and the suction filtration is carried out after the solution is washed to neutral pH by using ultrapure water.
[0014] Preferably, in the S2 step, the temperature of the sealed hydrothermal treatment is 135-150 DEG C, the heating time is 10-12h, the calcination temperature is 500 DEG C, and the calcination time is 2h.
[0015] Preferably, in the S3 step, the mass concentration of the thorn-like Fe2O3 / C mixed solution configured is 2g / L; the mass concentration of AgNO3 is 8mg / L; the power of the xenon lamp used is 300w, the spectral range is 200nm-2000nm, and the irradiation time is 50-60min.
[0016] Preferably, in the S3 step, after the reaction, the precipitate is centrifuged at 7000-8000rpm in a high-speed centrifuge for 10min, and then washed twice by using anhydrous ethanol and once by using deionized water.
[0017] Preferably, in the S3 step, the centrifuged sample is placed into a vacuum drying oven for drying, the temperature is controlled at 40 DEG C, the vacuum drying time is 24h, and the grinding time is not less than 10min.
[0018] The composite material catalyst is prepared by the preparation method.
[0019] The composite material catalyst is used for treating pollutants in sewage, and the specific steps are as follows.
[0020] Step one, a 300W xenon lamp is used as a light source, a 420nm cutoff filter is prepared, ultrapure water is used as a solvent, condensate water is introduced to control the reaction temperature at 25 DEG C, 20mmol / L concentration H2O2 is added, the solution pH is 3, and 10mg / L concentration methylene blue is used as a dye degradation product;
[0021] Step two, the photocatalyst is subjected to the performance test of photo-Fenton, 4mL supernatant is taken every 5 minutes, is centrifuged in a high-speed centrifuge, the intensity of the maximum absorption peak is detected by using a UV-visible spectrophotometer, the residual concentration of methylene blue is determined according to the intensity of the absorption peak, and the photo-Fenton performance of the catalyst is determined according to the concentration-time curve of methylene blue.
[0022] The application provides a preparation method of a composite material catalyst and application thereof.
[0023] 1、The application can significantly improve the cycle number of the material by introducing Ag nanoparticles, the synthesized thorn-like Fe2O3 has the advantages of larger specific surface area and faster surface reaction rate, and has the characteristics of high conductivity and low photo-generated carrier recombination rate.
[0024] 2、In the composite material catalyst provided by the application, the Ag nanoparticles are anchored on the surface of the thorn-like Fe2O3, and the thorn-like Fe2O3 is staggered loaded on the three-dimensional porous structure of the carbonized pollen, the structure increases the specific surface area of the material, provides more reaction active sites, increases the contact probability of the reaction active sites and pollutants, and improves the treatment effect of the pollutants.
[0025] 3、The composite material catalyst provided in the application has high mechanical strength and large specific surface area due to the thorn-like structure of Fe2O3, and the highly directional structure can increase light reflection and improve light absorption efficiency.
[0026] 4、In the application, the three-dimensional porous structure of the carbonized pollen can play a supporting role, thereby improving the specific surface area of the material, increasing the reaction active sites of the photo-generated holes and the solution, and improving the photocatalytic performance of the material. BRIEF DESCRIPTION OF DRAWINGS
[0027] Figure 1 It is a material preparation flowchart of the application;
[0028] Figure 2 It is a SEM schematic diagram of the application, a is 7000 times, and b is 22000 times;
[0029] Figure 3 It is an XRD diagram schematic diagram of Ag@Fe2O3 / C and Fe2O3 / C of the application;
[0030] Figure 4 It is a material PL photoluminescence spectrum schematic diagram of the application;
[0031] Figure 5 It is an electrochemical impedance schematic diagram of the material of the application;
[0032] Figure 6 The schematic diagram of the degradation rate-time curve of methylene blue under different conditions of the Ag@Fe2O3 / C of the application is shown in the figure;
[0033] Figure 7 The schematic diagram of the cycle times of the Ag@Fe2O3 / C of the application is shown in the figure. DETAILED DESCRIPTION
[0034] The technical solutions in the embodiments of the application will be clearly and completely described in the specification of the application with reference to the accompanying drawings of the application. Obviously, the described embodiments are only a part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all the other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the application.
[0035] Embodiment:
[0036] Please refer to the accompanying drawings of the application Figure 1 The embodiment of the application provides a preparation method of a composite material catalyst, which comprises the following method steps:
[0037] Firstly, 10 g of rape pollen is soaked in 100 mL of anhydrous ethanol and ultrasonically treated for 2 h, then the sample is filtered on a 0.22 μm filter membrane with ultrapure water, a mixed solution of anhydrous ethanol and formalin with a volume ratio of 1:1 is prepared at 100 mL, the filtered pollen is put into the mixed solution and stirred for 1 h, after filtration, the sample is poured into 100 mL of 80 DEG C 12M concentrated sulfuric acid and soaked for 4 h, then the sample is repeatedly washed with ultrapure water until the pH is neutral, and then the sample is suction filtered and placed in a vacuum drying box for 24 h.
[0038] Secondly, 0.404 g of Fe(NO3)3·9H2O is weighed in 30 mL of deionized water, 0.80 g of CTAB and 0.201 g of NaF are added on a magnetic stirrer while stirring, then the solution is stirred until uniform, 1.00 g of NaOH is added, 0.2 g of carbonized rape pollen is added and the solution is continuously stirred until uniform, then the solution is loaded into a reaction kettle, the temperature is set to 150 DEG C, and the solution is reacted in an oven for 12 hours; after natural cooling, the supernatant is removed, the precipitate is washed with anhydrous ethanol twice and deionized water once, and then the precipitate is dried and calcined in a muffle furnace at a temperature of 500 DEG C for 2 h.
[0039] Thirdly, 0.2 g of the synthesized sample was dispersed in 200 mL of ultrapure water and ultrasonically treated for 30 minutes. Then, 2.0 mL of 5% polyethylene glycol was added, and the solution was stirred for another 30 minutes to obtain a uniform solution. Next, 1.2 mL of AgNO3 solution (2.5 g / L) was added, and the solution was transferred to a water-cooled reactor and irradiated using a 300 W xenon lamp for 60 minutes at an irradiation intensity of 200 mWcm -2 Finally, after being washed twice with anhydrous ethanol and once with deionized water, and dried in a vacuum box at 40℃ for 24 hours, a solid powder sample was obtained, which was a composite catalyst product with the chemical formula Ag@Fe2O3 / C.
[0040] As shown in FIG. 1, the composite catalyst in the embodiment was prepared by the above preparation method, and the degradation rate of methylene blue reached 95% within 30 minutes of reaction time under the condition of 20 mg / L of H2O2. Figure 6
[0041] As shown in FIG. 1, the composite catalyst in the embodiment was prepared by the above preparation method, and the degradation rate of methylene blue reached 95% within 30 minutes of reaction time under the condition of 20 mg / L of H2O2. Figure 7 As shown in FIG. 1, the composite catalyst in the embodiment was prepared by the above preparation method, and the degradation rate of methylene blue reached 95% within 30 minutes of reaction time under the condition of 20 mg / L of H2O2.
[0042] Step one: a 300 W xenon lamp was used as a light source, a 420 nm cutoff filter was prepared, ultrapure water was used as a solvent, and condensate water was introduced to control the reaction temperature at 25℃, 20 mg / L of H2O2 was added, the pH of the solvent was 3, and 10 mg / L of methylene blue was used as a dye degradation substance.
[0043] Step two: the photocatalyst was tested for its performance in the photo-Fenton reaction, 4 mL of supernatant was taken every 5 minutes and centrifuged in a high-speed centrifuge, the intensity of the maximum absorption peak was detected using a UV-visible spectrophotometer, the residual concentration of methylene blue was determined according to the intensity of the absorption peak, and the performance of the catalyst in the photo-Fenton reaction was determined according to the concentration-time curve of methylene blue.
[0044] Specifically, the degradation of the composite catalyst on the methylene blue solution under the condition of 20 mg / L of H2O2 could be repeated for 8 times, and the degradation rate did not change significantly, and the stability could still be maintained after the 30th time.
[0045] Further, the composite material catalyst prepared by the preparation method provided by the application can change the specific surface area of the composite material catalyst when applied in a photo-Fenton reaction, so that the Ag-doped spiculate Fe2O3 carbonized rape pollen catalyst with high mechanical strength, high conductivity, low photo-generated carrier recombination rate, excellent catalytic performance and strong catalyst stability is obtained, and the efficient cyclic degradation of methylene blue is realized. In a specific application experiment, the photo-generated carrier recombination rate of the Ag-doped spiculate Fe2O3 carbonized rape pollen catalyst is three times that of the spiculate Fe2O3 / C and six times that of the spiculate Fe2O3, the degradation rate of methylene blue reaches 95% within 30 min of reaction time under the condition of 20 mg / L of H2O2, and the degradation rate does not change obviously after 8 times of cyclic degradation.
[0046] The composite material catalyst obtained by the embodiment is subjected to scanning electron microscopy, X-ray diffraction, fluorescence spectrophotometry and EIS electrochemical impedance measurement, and the test results are shown in Figs. Figure 2 , Fig. Figure 3 , Fig. Figure 4 and Fig. Figure 5 .
[0047] The Ag nanoparticles of the Ag-doped spiculate Fe2O3 carbonized rape pollen catalyst are deposited on the spiculate Fe2O3, and the spiculate Fe2O3 grows on the carbonized rape pollen, so that the contact area of the catalyst and the reactant is greatly increased, and the reaction active site of the photo-generated hole and the solution is increased, the specific surface area of the material is increased, and the separation of the photo-generated electron and hole is promoted by reducing the diffusion length.
[0048] In the application, the carbonized rape pollen has a natural three-dimensional skeleton, the specific surface area of the material is increased, the mechanical strength of the catalyst is improved, the stability of the catalyst is enhanced, the Fe2O3 has a spiculate structure, the highly branched structure enhances the strength and toughness of the catalyst, the electron can be transmitted faster in the inside, the reaction activity is improved, the Ag nanoparticles are deposited on the surface of the spiculate Fe2O3, the conductivity of the catalyst is improved, the separation efficiency of the photo-generated electron and hole is enhanced, the Ag nanoparticles provide more active sites, the intermediate product can be neutralized, and the stability and life of the catalyst are improved.
[0049] Although the embodiments of the application have been shown and described, it can be understood by those of ordinary skill in the art that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and spirits of the application, and the scope of the application is defined by the appended claims and their equivalents.
Claims
1. A method for preparing a composite catalyst, the catalyst comprising Ag nanoparticles, spiky Fe2O3, and carbonized rapeseed pollen, characterized in that, Ag nanoparticles are deposited on spiky Fe2O3, which in turn grows on carbonized rapeseed pollen. The preparation process includes the following steps: S1, Preparation of carbonized rapeseed pollen substrate C: Rapeseed pollen was soaked in anhydrous ethanol and subjected to ultrasonic treatment. Then it was soaked in a mixed solution of anhydrous ethanol and formalin, filtered, poured into concentrated sulfuric acid, stirred, filtered, and dried to obtain carbonized rapeseed pollen. In step S1, the mass ratio of rapeseed pollen to anhydrous ethanol mixed solution is 1:10; the volume ratio of anhydrous ethanol to formalin mixed solution is between 0.5 and 2; the filtered pollen sample is poured into 12M concentrated sulfuric acid and soaked in an oil bath at 75-80°C for 4 hours. Preparation of S2 and spiky Fe2O3 / C: The carbonized rapeseed pollen was placed in a mixed solution of ferric nitrate nonahydrate, sodium fluoride, cationic surfactant, and NaOH and subjected to sealed hydrothermal treatment. The hydrothermally treated material was then calcined to obtain spiky Fe2O3 / C material. In step S2, the temperature of the sealing hydrothermal system is 135-150℃, the heating time is 10-12h, the calcination temperature is 500℃, and the calcination time is 2h. Preparation of S3 and Ag@Fe2O3 / C: The spiky Fe2O3 / C was prepared into a mixed solution, and polyethylene glycol solution was added and stirred. Then AgNO3 was added, and photodeposition was performed using a xenon lamp to obtain a precipitate. After centrifugation and drying, the precipitate was ground into powder using a mortar and pestle to obtain a powder sample. In step S3, the mass concentration of the prepared spiky Fe2O3 / C mixed solution is 1 g / L; the mass concentration of AgNO3 is 6-10 mg / L; the xenon lamp power is 300 W, the spectral range is 200 nm-2000 nm, and the irradiation time is 50-60 min.
2. The method for preparing a composite catalyst according to claim 1, characterized in that, In step S1, the solution after soaking in concentrated sulfuric acid is filtered, and then rinsed with ultrapure water to make the pH neutral before filtration.
3. The method for preparing a composite catalyst according to claim 1, characterized in that, In step S3, the precipitate after the reaction is centrifuged at 7000-8000 rpm for 10 min in a high-speed centrifuge, then washed twice with anhydrous ethanol and once with deionized water.
4. The method for preparing a composite catalyst according to claim 1, characterized in that, In step S3, the centrifuged sample is placed in a vacuum drying oven for drying at a temperature of 40°C for 24 hours, and the grinding time is not less than 10 minutes.
5. A composite material catalyst, characterized in that, The catalyst is prepared by the preparation method according to any one of claims 1-4.
6. The application of the composite catalyst prepared by the preparation method according to any one of claims 1-4, wherein the catalyst is used for the treatment of pollutants in wastewater, characterized in that, The specific steps are as follows: Step 1: Use a 300W xenon lamp as the light source, prepare a 420nm cutoff filter, use ultrapure water as the solvent, pass in condensing water to control the reaction temperature at 25℃, add 20mmol / L H2O2, the solution pH is 3, and 10mg / L methylene blue as the dye degradation product. Step 2: Perform photo-Fenton performance testing on the photocatalyst. Take 4 mL of supernatant every 5 minutes, centrifuge in a high-speed centrifuge, and use a UV-Vis spectrophotometer to detect the intensity of the maximum absorption peak. Determine the residual concentration of methylene blue based on the intensity of the absorption peak, and determine the photo-Fenton performance of the catalyst based on the concentration-time curve of methylene blue.