Aerogel photo-Fenton catalyst as well as preparation method and application thereof

Abstract

The invention discloses an aerogel photo-Fenton catalyst as well as a preparation method and application thereof, and belongs to the technical field of photocatalysts. The preparation method of the aerogel photo-Fenton catalyst comprises the following steps: firstly, preparing polyhydroxy iron pillaring agent intercalation modified bentonite, and roasting to obtain gamma-FeO-Pil-Bent; then loading BiVO4 by virtue of a hydrothermal method, so as to obtain BiVO4 / gamma-Fe2O3-Pil-Bent; and finally, compounding the PANI / BiVO4 / gamma-Fe2O3-Pli-Bent aerogel with aniline and a PVA (Polyvinyl Alcohol) aqueous solution, and carrying out freeze-thaw cycle and in-situ polymerization reaction, and freeze-drying to obtain the PANI / BiVO4 / gamma-Fe2O3-Pli-Bent aerogel photo-Fenton catalyst. The prepared aerogel photo-Fenton catalyst has a three-dimensional continuous network structure, rich active sites are provided for a photocatalytic reaction, efficient separation of photo-induced electron-hole pairs is achieved through a heterojunction structure formed by PANI and BiVO4, meanwhile, photo-induced electrons generated by BiVO4 can promote reduction of Fe < 3 + > into Fe < 2 + >, the photo-Fenton catalytic efficiency is remarkably improved, and the photocatalytic activity of the photocatalyst is improved. The degradation rate of the catalyst to rhodamine B under sunlight can reach 90% or above within 30 min.

Description

Technical Field

[0001] This invention relates to the field of photocatalyst technology, specifically to an aerogel photo-Fenton catalyst, its preparation method, and its application. Background Technology

[0002] With the rapid development of the dye industry, including textiles, printing and dyeing, leather, and papermaking, a large amount of organic wastewater has been generated. This type of wastewater is characterized by complex composition, high COD, resistance to oxidation and photolysis, strong thermal stability, poor biodegradability, and high toxicity, posing a serious threat to the environment and human health. Traditional water treatment technologies are insufficient to effectively remove these organic pollutants.

[0003] Advanced oxidation processes (AOPs) based on heterogeneous photo-Fenton systems can react at neutral temperatures and room temperature, effectively removing organic pollutants from wastewater. However, traditional heterogeneous photo-Fenton catalysts still suffer from problems such as high recombination rates of photogenerated electrons and holes, low quantum efficiency, low visible light utilization, low solar energy utilization efficiency, limited catalyst specific surface area, and insufficient adsorption capacity. These limitations restrict the application of heterogeneous photo-Fenton catalysts in practical water treatment processes.

[0004] Aerogel photocatalysts are porous photocatalytic materials with a three-dimensional continuous network structure. They possess advantages such as low density, large specific surface area, uniform pore size distribution, and good light transmittance. They can provide a large number of active sites for the photocatalytic process and also solve the problems of dispersion and recycling of photocatalytic materials. Polyaniline (PANI) is one of the heterocyclic conjugated conductive polymers, possessing good electrical conductivity, electron transport capability, and chemical stability.

[0005] Therefore, developing an aerogel-supported photo-Fenton catalyst that combines excellent conductivity, easy recyclability, and high photocatalytic activity is of great practical significance for improving the treatment efficiency of organic pollutant wastewater. Summary of the Invention

[0006] In view of this, the present invention provides an aerogel photo-Fenton catalyst, its preparation method and application. The PANI / BiVO4 / γ-Fe2O3-Pil-Bent aerogel photo-Fenton catalyst prepared by the present invention has a three-dimensional continuous network structure, which realizes the efficient separation of photogenerated electron-hole pairs and improves the visible light photocatalytic activity.

[0007] The technical solution provided by this invention is as follows: This invention provides a method for preparing an aerogel photo-Fenton catalyst, comprising the following steps: Preparation of S1.γ-Fe2O3-Pil-Bent Fe(NO3)3 solution was added to the reaction vessel and heated to 50-70℃. Na2CO3 solution was added dropwise under stirring and the mixture was stirred and aged for 12-36 h to obtain the polymerized hydroxyl iron columnar agent. Bentonite and sodium dodecyl sulfate were dispersed in deionized water and stirred at 50-70°C for 1-3 hours. Polymerized hydroxyl iron columnarizing agent was added dropwise and stirring was continued for 2-6 hours. After standing overnight, the mixture was washed with deionized water, centrifuged, dried, calcined, cooled, and ground to obtain γ-Fe2O3-Pil-Bent. Preparation of S2.BiVO4 / γ-Fe2O3-Pil-Bent Disperse the γ-Fe2O3-Pil-Bent prepared in step S1 in deionized water, add Bi(NO3)3 solution dropwise, stir for 4-8 h, then add Na3VO4 solution dropwise, stir for 0.5-2 h, react at 160-200℃ for 6-18 h, cool, wash with deionized water, dry, cool, and grind to obtain BiVO4 / γ-Fe2O3-Pil-Bent; Preparation of S3.PANI / BiVO4 / γ-Fe2O3-Pil-Bent The BiVO4 / γ-Fe2O3-Pil-Bent prepared in step S2 was dispersed in deionized water, PVA aqueous solution and aniline monomer were added, and after ultrasonic dispersion and removal of air bubbles, it was poured into a petri dish and subjected to freeze-thaw cycles to obtain a hydrogel. Ammonium persulfate and hydrochloric acid were added to the hydrogel, and the reaction was polymerized for 4-6 h. After the reaction was completed, it was washed with deionized water and freeze-dried for 8-16 h to obtain PANI / BiVO4 / γ-Fe2O3-Pil-Bent, which is the aerogel photo-Fenton catalyst.

[0008] Preferably, in step S1, the concentration of the Fe(NO3)3 solution is 0.2M, the concentration of the Na2CO3 solution is 0.5M, and the Fe... 3+ with Na + The molar ratio is 1:(1-1.5).

[0009] Preferably, Fe in step S1 3+ The ratio of bentonite to sodium dodecyl sulfate is (5-15) mmol:1g, and the mass ratio of bentonite to sodium dodecyl sulfate is 1:(0.1-0.3).

[0010] Preferably, the calcination in step S1 is carried out at 350-450℃ for 2-4 hours.

[0011] Preferably, in step S2, the mass ratio of γ-Fe₂O₃-Pil-Bent to deionized water and Bi(NO₃)₃ solution is (0.1-0.5):30:10, and Bi 3+ With VO4 3-The molar ratio is 1:(0.8-1.2); the concentration of Bi(NO3)3 solution is 5%-20%, and the concentration of Na3VO4 solution is 0.1M.

[0012] Preferably, in step S3, the mass ratio of BiVO4 / γ-Fe2O3-Pil-Bent to deionized water is (0.01-0.05):30, the freeze-thaw cycle temperature is -20℃ to 25℃, and the number of cycles is 2-5.

[0013] Based on the same inventive concept, the present invention provides an aerogel photo-Fenton catalyst, which is prepared by any of the above-described methods for preparing an aerogel photo-Fenton catalyst.

[0014] Based on the same inventive concept, this invention provides the application of an aerogel photo-Fenton catalyst as described above in the catalytic degradation of organic dye pollutants under sunlight.

[0015] Preferably, the organic dye pollutant is Rhodamine B.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The PANI / BiVO4 / γ-Fe2O3-Pil-Bent aerogel photo-Fenton catalyst prepared by this invention has a three-dimensional continuous network structure, which not only provides abundant active sites for photocatalytic reactions, but also effectively improves the dispersibility and recovery performance of the catalytic material, which is beneficial to its practical application in the field of water treatment.

[0017] 2. As an excellent electron donor, PANI forms a heterojunction structure with BiVO4. Under photoexcitation, electrons in the π* orbital of PANI can be rapidly transferred to the conduction band of BiVO4, while holes in the valence band of BiVO4 migrate to the π orbital of PANI, thereby achieving efficient separation of photogenerated electron-hole pairs and significantly improving photocatalytic efficiency.

[0018] 3. Photogenerated electrons produced by BiVO4 under illumination can promote Fe 3+ Reduced to Fe 2+ This accelerates the photo-Fenton reaction cycle; simultaneously, Fe 3+ The / H2O2 system, acting as an electron acceptor, can effectively promote the separation of photogenerated electrons and holes. This catalyst achieves a degradation rate of over 90% for Rhodamine B within 30 minutes, demonstrating excellent photo-Fenton catalytic performance.

[0019] 4. The preparation method of the present invention is simple, uses readily available raw materials, is environmentally friendly, has good application prospects, and is suitable for the field of organic wastewater treatment. Attached Figure Description

[0020] Figure 1SEM image of the PANI / BiVO4 / γ-Fe2O3-Pil-Bent aerogel photo-Fenton catalyst prepared in Example 3 of this invention.

[0021] Figure 2 The degradation efficiency (a) and color change (b) of Rhodamine B by the PANI / BiVO4 / γ-Fe2O3-Pil-Bent aerogel photo-Fenton catalyst prepared in Example 3 of this invention are shown. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention. It should be noted that, unless otherwise specified, all chemical reagents involved in this invention are purchased through commercial channels.

[0023] The English abbreviation and the full Chinese name used in this invention are as follows: Bentonite, sodium dodecyl sulfate (SDS), and polyaniline (PANI). Example

[0024] A method for preparing an aerogel photo-Fenton catalyst includes the following steps: Preparation of S1.γ-Fe2O3-Pil-Bent A 0.2M Fe(NO3)3 solution was added to a reaction vessel and heated to 50°C. A 0.5M Na2CO3 solution was then added dropwise under stirring, causing the Fe... 3+ with Na + The molar ratio was 1:1, and the mixture was stirred and aged for 12 hours to obtain the polymerized hydroxyl iron columnar oxidizing agent. One part bentonite and 0.1 part sodium dodecyl sulfate were dispersed in 50 parts deionized water and stirred at 50°C for 1 hour. A polymeric hydroxyl iron columnarizing agent was then added dropwise to allow Fe... 3+ Add 5 mmol / g of bentonite, continue stirring for 2 hours, let stand overnight, wash with deionized water, centrifuge, dry at 60℃, calcine at 350℃ for 2 hours, cool and grind to obtain γ-Fe2O3-Pil-Bent. Preparation of S2.BiVO4 / γ-Fe2O3-Pil-Bent Take 0.1 part of the γ-Fe2O3-Pil-Bent prepared in step S1 and disperse it in 30 parts of deionized water. Add 10 parts of 5% Bi(NO3)3 aqueous solution dropwise and stir magnetically for 6 hours. Then add 0.1M Na3VO4 aqueous solution dropwise to make Bi... 3+ With VO4 3- The molar ratio was 1:0.8. After stirring for 0.5 h, the mixture was transferred to a hydrothermal reactor and reacted at 160 °C for 6 h. After cooling, the mixture was washed with deionized water until neutral, dried at 60 °C, cooled and ground to obtain BiVO4 / γ-Fe2O3-Pil-Bent. Preparation of S3.PANI / BiVO4 / γ-Fe2O3-Pil-Bent Take 0.01 parts of BiVO4 / γ-Fe2O3-Pil-Bent prepared in step S2 and uniformly disperse it in 30 parts of deionized water. Add 8 parts of 10wt% PVA aqueous solution and 0.3 parts of aniline monomer. After ultrasonic dispersion and removal of air bubbles, pour it into a petri dish and freeze-thaw twice at -20℃ to room temperature to obtain hydrogel. Add 0.1 parts of ammonium persulfate and 20 parts of 1M hydrochloric acid to the hydrogel and react and polymerize for 4 hours. After the reaction, wash with deionized water until neutral and freeze-dry for 8 hours to obtain PANI / BiVO4 / γ-Fe2O3-Pil-Bent, which is the aerogel photo-Fenton catalyst.

[0025] Application of an aerogel photo-Fenton catalyst in the catalytic degradation of Rhodamine B under sunlight: Fifty portions of 20 mg / L Rhodamine B aqueous solution were added to a light-protected catalytic reactor. 0.1 g / L of the prepared PANI / BiVO4 / γ-Fe2O3-Pil-Bent aerogel photo-Fenton catalyst and 5 mM H2O2 were added to initiate a heterogeneous photo-Fenton reaction. The initial solution pH was adjusted with 0.1 M H2SO4 and NaOH. A 300 W high-pressure xenon lamp equipped with a 420 nm filter was turned on to simulate sunlight, and degradation was carried out at room temperature. Before the reaction, a dark reaction was conducted at room temperature to allow the composite catalyst and Rhodamine B solution to reach adsorption-desorption equilibrium. During the reaction, 3 mL of sample was taken every 10 min, filtered through a 0.22 μm filter, and 0.1 mL of methanol was added as a reaction terminator to remove residual free radicals. The absorbance was then measured at 554 nm using a UV-Vis spectrophotometer to calculate the degradation rate of Rhodamine B. To ensure the reliability of the experiment, each experiment was conducted in parallel three times and the standard deviation was controlled; under these conditions, the degradation rate of Rhodamine B reached 94.83% within 30 minutes. Example

[0026] A method for preparing an aerogel photo-Fenton catalyst includes the following steps: Preparation of S1.γ-Fe2O3-Pil-Bent A 0.2M Fe(NO3)3 solution was added to a reaction vessel and heated to 55°C. A 0.5M Na2CO3 solution was then added dropwise under stirring, causing the Fe... 3+ with Na + The molar ratio was 1:1.2, and the mixture was stirred and aged for 18 hours to obtain a polymerized hydroxyl iron columnar oxidizing agent. One part bentonite and 0.15 parts sodium dodecyl sulfate were dispersed in 50 parts deionized water and stirred at 55°C for 1 hour. A polymeric hydroxyl iron columnarizing agent was then added dropwise to allow Fe... 3+ Add 5 mmol / g of bentonite, continue stirring for 3 hours, let stand overnight, wash with deionized water, centrifuge, dry at 60℃, calcine at 350℃ for 2.5 hours, cool and grind to obtain γ-Fe2O3-Pil-Bent; Preparation of S2.BiVO4 / γ-Fe2O3-Pil-Bent Take 0.2 parts of the γ-Fe2O3-Pil-Bent prepared in step S1 and disperse it in 30 parts of deionized water. Add 10 parts of 10% Bi(NO3)3 aqueous solution dropwise and stir magnetically for 5 hours. Then add 0.1M Na3VO4 aqueous solution dropwise to make Bi... 3+ With VO4 3- The molar ratio was 1:0.9. After stirring for 0.5 h, the mixture was transferred to a hydrothermal reactor and reacted at 170 °C for 8 h. After cooling, the mixture was washed with deionized water until neutral, dried at 60 °C, cooled and ground to obtain BiVO4 / γ-Fe2O3-Pil-Bent. Preparation of S3.PANI / BiVO4 / γ-Fe2O3-Pil-Bent Take 0.02 parts of BiVO4 / γ-Fe2O3-Pil-Bent prepared in step S2 and uniformly disperse it in 30 parts of deionized water. Add 9 parts of 10wt% PVA aqueous solution and 0.4 parts of aniline monomer. After ultrasonic dispersion and removal of air bubbles, pour it into a petri dish and freeze-thaw three times from -20℃ to room temperature to obtain hydrogel. Add 0.15 parts of ammonium persulfate and 20 parts of 1M hydrochloric acid to the hydrogel and react and polymerize for 4.5 h. After the reaction, wash with deionized water until neutral and freeze-dry for 10 h to obtain PANI / BiVO4 / γ-Fe2O3-Pil-Bent, which is the aerogel photo-Fenton catalyst.

[0027] Application of an aerogel photo-Fenton catalyst in the catalytic degradation of Rhodamine B under sunlight: Fifty portions of 20 mg / L Rhodamine B aqueous solution were added to a light-protected catalytic reactor. 0.1 g / L of the prepared PANI / BiVO4 / γ-Fe2O3-Pil-Bent aerogel photo-Fenton catalyst and 5 mM H2O2 were added to initiate a heterogeneous photo-Fenton reaction. The initial solution pH was adjusted with 0.1 M H2SO4 and NaOH. A 300 W high-pressure xenon lamp equipped with a 420 nm filter was turned on to simulate sunlight, and degradation was carried out at room temperature. Before the reaction, a dark reaction was conducted at room temperature to allow the composite catalyst and Rhodamine B solution to reach adsorption-desorption equilibrium. During the reaction, 3 mL of sample was taken every 10 min, filtered through a 0.22 μm filter, and 0.1 mL of methanol was added as a reaction terminator to remove residual free radicals. The absorbance was then measured at 554 nm using a UV-Vis spectrophotometer to calculate the degradation rate of Rhodamine B. To ensure the reliability of the experiment, each experiment was conducted in parallel three times and the standard deviation was controlled; under these conditions, the degradation rate of Rhodamine B reached 95.57% within 30 minutes. Example

[0028] A method for preparing an aerogel photo-Fenton catalyst includes the following steps: Preparation of S1.γ-Fe2O3-Pil-Bent A 0.2M Fe(NO3)3 solution was added to a reaction vessel and heated to 60°C. A 0.5M Na2CO3 solution was then added dropwise under stirring, causing the Fe... 3+ with Na + The molar ratio was 1:1.3, and the mixture was stirred and aged for 24 hours to obtain a polymerized hydroxyl iron columnar oxidizing agent. One part bentonite and 0.2 parts sodium dodecyl sulfate were dispersed in 50 parts deionized water and stirred at 60°C for 2 hours. A polymeric hydroxyl iron columnarizing agent was then added dropwise to allow Fe... 3+ The mixture was stirred for 4 hours with bentonite at a concentration of 10 mmol / g. After standing overnight, it was washed with deionized water, centrifuged, dried at 60℃, calcined at 400℃ for 3 hours, cooled and ground to obtain γ-Fe2O3-Pil-Bent. Preparation of S2.BiVO4 / γ-Fe2O3-Pil-Bent Take 0.1 part of the γ-Fe2O3-Pil-Bent prepared in step S1 and disperse it in 30 parts of deionized water. Add 10 parts of 15% Bi(NO3)3 aqueous solution dropwise and stir magnetically for 6 hours. Then add 0.1M Na3VO4 aqueous solution dropwise to make Bi... 3+ With VO4 3-The molar ratio was 1:0.8. After stirring for 0.5 h, the mixture was transferred to a hydrothermal reactor and reacted at 160 °C for 12 h. After cooling, the mixture was washed with deionized water until neutral, dried at 60 °C, cooled and ground to obtain BiVO4 / γ-Fe2O3-Pil-Bent. Preparation of S3.PANI / BiVO4 / γ-Fe2O3-Pil-Bent Take 0.03 parts of BiVO4 / γ-Fe2O3-Pil-Bent prepared in step S2 and uniformly disperse it in 30 parts of deionized water. Add 10 parts of 10wt% PVA aqueous solution and 0.5 parts of aniline monomer. After ultrasonic dispersion and removal of air bubbles, pour it into a petri dish and freeze-thaw 4 times from -20℃ to room temperature to obtain hydrogel. Add 0.2 parts of ammonium persulfate and 20 parts of 1M hydrochloric acid to the hydrogel and react and polymerize for 5 hours. After the reaction, wash with deionized water until neutral and freeze-dry for 10 hours to obtain PANI / BiVO4 / γ-Fe2O3-Pil-Bent, which is the aerogel photo-Fenton catalyst.

[0029] Figure 1 This is a SEM image of the PANI / BiVO4 / γ-Fe2O3-Pil-Bent aerogel photo-Fenton catalyst prepared in this embodiment. Figure 1 This indicates that the PANI / BiVO4 / γ-Fe2O3-Pil-Bent aerogel photo-Fenton catalyst has a three-dimensional continuous network structure.

[0030] Application of an aerogel photo-Fenton catalyst in the catalytic degradation of Rhodamine B under sunlight: Fifty portions of 20 mg / L Rhodamine B aqueous solution were added to a light-protected catalytic reactor. 0.1 g / L of the prepared PANI / BiVO4 / γ-Fe2O3-Pil-Bent aerogel photo-Fenton catalyst and 5 mM H2O2 were added to initiate a heterogeneous photo-Fenton reaction. The initial solution pH was adjusted with 0.1 M H2SO4 and NaOH. A 300 W high-pressure xenon lamp equipped with a 420 nm filter was turned on to simulate sunlight, and degradation was carried out at room temperature. Before the reaction, a dark reaction was conducted at room temperature to allow the composite catalyst and Rhodamine B solution to reach adsorption-desorption equilibrium. During the reaction, 3 mL of sample was taken every 10 min, filtered through a 0.22 μm filter, and 0.1 mL of methanol was added as a reaction terminator to remove residual free radicals. The absorbance was then measured at 554 nm using a UV-Vis spectrophotometer to calculate the degradation rate of Rhodamine B. To ensure the reliability of the experiment, each experiment was conducted in parallel three times and the standard deviation was controlled; under these conditions, the degradation rate of Rhodamine B reached 96.20% within 30 minutes.

[0031] Figure 2The degradation efficiency (a) and color change (b) of Rhodamine B by the PANI / BiVO4 / γ-Fe2O3-Pil-Bent aerogel photo-Fenton catalyst prepared in this embodiment show that the degradation rate reaches more than 96.20% within 30 min. Example

[0032] A method for preparing an aerogel photo-Fenton catalyst includes the following steps: Preparation of S1.γ-Fe2O3-Pil-Bent A 0.2M Fe(NO3)3 solution was added to a reaction vessel and heated to 65°C. A 0.5M Na2CO3 solution was then added dropwise under stirring, causing the Fe... 3+ with Na + The molar ratio was 1:1.4, and the mixture was stirred and aged for 30 hours to obtain a polymerized hydroxyl iron columnar oxidizing agent. One part bentonite and 0.25 parts sodium dodecyl sulfate were dispersed in 50 parts deionized water and stirred at 65°C for 2.5 hours. A polymerizing hydroxyl iron columnarizing agent was then added dropwise to allow Fe... 3+ The mixture was stirred for 4 hours with bentonite at a concentration of 15 mmol / g. After standing overnight, it was washed with deionized water, centrifuged, dried at 60℃, calcined at 400℃ for 3 hours, cooled and ground to obtain γ-Fe2O3-Pil-Bent. Preparation of S2.BiVO4 / γ-Fe2O3-Pil-Bent Take 0.4 parts of the γ-Fe2O3-Pil-Bent prepared in step S1 and disperse it in 30 parts of deionized water. Add 10 parts of 20% Bi(NO3)3 aqueous solution dropwise and stir magnetically for 7 hours. Then add 0.1M Na3VO4 aqueous solution dropwise to make Bi... 3+ With VO4 3- The molar ratio was 1:1.1. After stirring for 1.5 h, the mixture was transferred to a hydrothermal reactor and reacted at 190 °C for 16 h. After cooling, the mixture was washed with deionized water until neutral, dried at 60 °C, cooled and ground to obtain BiVO4 / γ-Fe2O3-Pil-Bent. Preparation of S3.PANI / BiVO4 / γ-Fe2O3-Pil-Bent Take 0.04 parts of BiVO4 / γ-Fe2O3-Pil-Bent prepared in step S2 and uniformly disperse it in 30 parts of deionized water. Add 11 parts of 10wt% PVA aqueous solution and 0.7 parts of aniline monomer. After ultrasonic dispersion and removal of air bubbles, pour it into a petri dish and freeze-thaw 5 times from -20℃ to room temperature to obtain hydrogel. Add 0.15 parts of ammonium persulfate and 20 parts of 1M hydrochloric acid to the hydrogel and react and polymerize for 5.5 h. After the reaction, wash with deionized water until neutral and freeze-dry for 10 h to obtain PANI / BiVO4 / γ-Fe2O3-Pil-Bent, which is the aerogel photo-Fenton catalyst.

[0033] Application of an aerogel photo-Fenton catalyst in the catalytic degradation of Rhodamine B under sunlight: Fifty portions of 20 mg / L Rhodamine B aqueous solution were added to a light-protected catalytic reactor. 0.1 g / L of the prepared PANI / BiVO4 / γ-Fe2O3-Pil-Bent aerogel photo-Fenton catalyst and 5 mM H2O2 were added to initiate a heterogeneous photo-Fenton reaction. The initial solution pH was adjusted with 0.1 M H2SO4 and NaOH. A 300 W high-pressure xenon lamp equipped with a 420 nm filter was turned on to simulate sunlight, and degradation was carried out at room temperature. Before the reaction, a dark reaction was conducted at room temperature to allow the composite catalyst and Rhodamine B solution to reach adsorption-desorption equilibrium. During the reaction, 3 mL of sample was taken every 10 min, filtered through a 0.22 μm filter, and 0.1 mL of methanol was added as a reaction terminator to remove residual free radicals. The absorbance was then measured at 554 nm using a UV-Vis spectrophotometer to calculate the degradation rate of Rhodamine B. To ensure the reliability of the experiment, each experiment was conducted in parallel three times and the standard deviation was controlled; under these conditions, the degradation rate of Rhodamine B reached 95.67% within 30 minutes. Example

[0034] A method for preparing an aerogel photo-Fenton catalyst includes the following steps: Preparation of S1.γ-Fe2O3-Pil-Bent A 0.2M Fe(NO3)3 solution was added to a reaction vessel, heated to 70°C, and a 0.5M Na2CO3 solution was added dropwise under stirring, so that Fe... 3+ with Na + The molar ratio was 1:1.5, and the mixture was stirred and aged for 36 hours to obtain a polymerized hydroxyl iron columnar oxidizing agent. One part bentonite and 0.3 parts sodium dodecyl sulfate were dispersed in 50 parts deionized water and stirred at 70°C for 3 hours. A polymeric hydroxyl iron columnarizing agent was then added dropwise to allow Fe... 3+The mixture was stirred for 6 hours with bentonite at a concentration of 15 mmol / g. After standing overnight, it was washed with deionized water, centrifuged, dried at 60℃, calcined at 450℃ for 4 hours, cooled and ground to obtain γ-Fe2O3-Pil-Bent. Preparation of S2.BiVO4 / γ-Fe2O3-Pil-Bent Take 0.5 parts of the γ-Fe2O3-Pil-Bent prepared in step S1 and disperse it in 30 parts of deionized water. Add 10 parts of 20% Bi(NO3)3 aqueous solution dropwise and stir magnetically for 8 hours. Then add 0.1M Na3VO4 aqueous solution dropwise to make Bi... 3+ With VO4 3- The molar ratio was 1:1.2. After stirring for 2 hours, the mixture was transferred to a hydrothermal reactor and reacted at 200°C for 18 hours. After cooling, the mixture was washed with deionized water until neutral, dried at 60°C, cooled, and ground to obtain BiVO4 / γ-Fe2O3-Pil-Bent. Preparation of S3.PANI / BiVO4 / γ-Fe2O3-Pil-Bent Take 0.05 parts of BiVO4 / γ-Fe2O3-Pil-Bent prepared in step S2 and uniformly disperse it in 30 parts of deionized water. Add 12 parts of 10wt% PVA aqueous solution and 0.8 parts of aniline monomer. After ultrasonic dispersion and removal of air bubbles, pour it into a petri dish and freeze-thaw 5 times from -20℃ to room temperature to obtain hydrogel. Add 0.3 parts of ammonium persulfate and 20 parts of 1M hydrochloric acid to the hydrogel and react and polymerize for 6 hours. After the reaction, wash with deionized water until neutral and freeze-dry for 16 hours to obtain PANI / BiVO4 / γ-Fe2O3-Pil-Bent, which is the aerogel photo-Fenton catalyst.

[0035] Application of an aerogel photo-Fenton catalyst in the catalytic degradation of Rhodamine B under sunlight: Fifty portions of 20 mg / L Rhodamine B aqueous solution were added to a light-protected catalytic reactor. 0.1 g / L of the prepared PANI / BiVO4 / γ-Fe2O3-Pil-Bent aerogel photo-Fenton catalyst and 5 mM H2O2 were added to initiate a heterogeneous photo-Fenton reaction. The initial solution pH was adjusted with 0.1 M H2SO4 and NaOH. A 300 W high-pressure xenon lamp equipped with a 420 nm filter was turned on to simulate sunlight, and degradation was carried out at room temperature. Before the reaction, a dark reaction was conducted at room temperature to allow the composite catalyst and Rhodamine B solution to reach adsorption-desorption equilibrium. During the reaction, 3 mL of sample was taken every 10 min, filtered through a 0.22 μm filter, and 0.1 mL of methanol was added as a reaction terminator to remove residual free radicals. The absorbance was then measured at 554 nm using a UV-Vis spectrophotometer to calculate the degradation rate of Rhodamine B. To ensure the reliability of the experiment, each experiment was conducted in parallel three times and the standard deviation was controlled; under these conditions, the degradation rate of Rhodamine B reached 94.38% within 30 minutes.

[0036] The present invention and its embodiments have been described above. This description is not restrictive, and the embodiments shown are only one of the embodiments of the present invention. The actual structure is not limited to this. In conclusion, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the present invention, they should all fall within the protection scope of the present invention.

Claims

1. A method for preparing an aerogel photo-Fenton catalyst, characterized in that, Includes the following steps: Preparation of S1.γ-Fe2O3-Pil-Bent Fe(NO3)3 solution was added to the reaction vessel and heated to 50-70℃. Na2CO3 solution was added dropwise under stirring and the mixture was stirred and aged for 12-36 hours to obtain the polymerized hydroxyl iron columnarizing agent. Bentonite and sodium dodecyl sulfate were dispersed in deionized water and stirred at 50-70°C for 1-3 hours. Polymerized hydroxyl iron columnarizing agent was added dropwise and stirring was continued for 2-6 hours. After standing overnight, the mixture was washed with deionized water, centrifuged, dried, calcined, cooled, and ground to obtain γ-Fe2O3-Pil-Bent. Preparation of S2.BiVO4 / γ-Fe2O3-Pil-Bent Disperse the γ-Fe2O3-Pil-Bent prepared in step S1 in deionized water, add Bi(NO3)3 solution dropwise, stir for 4-8 h, then add Na3VO4 solution dropwise, stir for 0.5-2 h, react at 160-200℃ for 6-18 h, cool, wash with deionized water, dry, cool, and grind to obtain BiVO4 / γ-Fe2O3-Pil-Bent; Preparation of S3.PANI / BiVO4 / γ-Fe2O3-Pil-Bent The BiVO4 / γ-Fe2O3-Pil-Bent prepared in step S2 was dispersed in deionized water, PVA aqueous solution and aniline monomer were added, and after ultrasonic dispersion and removal of air bubbles, it was poured into a petri dish and subjected to freeze-thaw cycles to obtain a hydrogel. Ammonium persulfate and hydrochloric acid were added to the hydrogel, and the reaction was polymerized for 4-6 h. After the reaction was completed, it was washed with deionized water and freeze-dried for 8-16 h to obtain PANI / BiVO4 / γ-Fe2O3-Pil-Bent, which is the aerogel photo-Fenton catalyst.

2. The method for preparing an aerogel photo-Fenton catalyst according to claim 1, characterized in that, In step S1, the concentration of the Fe(NO3)3 solution is 0.2M, the concentration of the Na2CO3 solution is 0.5M, and the Fe... 3+ with Na + The molar ratio is 1:(1-1.5).

3. The method for preparing an aerogel photo-Fenton catalyst according to claim 1, characterized in that, Fe in step S1 3+ The ratio of bentonite to sodium dodecyl sulfate is (5-15) mmol:1g, and the mass ratio of bentonite to sodium dodecyl sulfate is 1:(0.1-0.3).

4. The method for preparing an aerogel photo-Fenton catalyst according to claim 1, characterized in that, In step S1, the roasting is carried out at 350-450℃ for 2-4 hours.

5. The method for preparing an aerogel photo-Fenton catalyst according to claim 1, characterized in that, In step S2, the mass ratio of γ-Fe₂O₃-Pil-Bent to deionized water and Bi(NO₃)₃ solution is (0.1-0.5):30:10, and Bi 3+ With VO4 3- The molar ratio is 1:(0.8-1.2); the concentration of Bi(NO3)3 solution is 5%-20%, and the concentration of Na3VO4 solution is 0.1M.

6. The method for preparing an aerogel photo-Fenton catalyst according to claim 1, characterized in that, In step S3, the mass ratio of BiVO4 / γ-Fe2O3-Pil-Bent to deionized water is (0.01-0.05):30, the freeze-thaw cycle temperature is -20℃ to 25℃, and the number of cycles is 2-5.

7. An aerogel photo-Fenton catalyst, characterized in that, It is prepared by the method for preparing an aerogel photo-Fenton catalyst according to any one of claims 1-6.

8. The application of the aerogel photo-Fenton catalyst as described in claim 7 in the catalytic degradation of organic dye pollutants under sunlight.

9. The application according to claim 8, wherein the organic dye contaminant is Rhodamine B.

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