A supergravity preparation method of a polymer-anchored metal nanoparticle catalyst and application thereof

Abstract

The application aims to provide a supergravity preparation method of polymerized anchoring metal nanoparticle catalyst and application thereof, belonging to the technical field of nanotechnology and wastewater treatment, wherein a carrier is loaded into a supergravity rotating packing bed; aniline monomer, an oxidizing agent and a metal salt are dissolved in an acid solution, and after being uniformly mixed, are delivered to the rotating packing bed through a centrifugal pump; under the action of supergravity, the solution is uniformly sprayed on the surface of the carrier, the aniline monomer is polymerized and synchronously anchors the metal active component in the process, and the reaction solution flows into a storage tank for circulation. Finally, the carrier loaded with the polymerized anchoring metal active component is taken out, high-temperature calcination is carried out in a tubular furnace, and the catalyst with small metal nanoparticle size and uniform dispersion can be obtained. Compared with a traditional stirring reactor, the preparation time is greatly shortened.

Description

Technical Field

[0001] This invention belongs to the fields of nanotechnology and wastewater treatment technology, specifically relating to a method for preparing polymer-anchored metal nanoparticle catalysts under ultragravity and its application. Background Technology

[0002] Recalcitrant and highly toxic organic pollutants in water bodies pose a serious threat to human health and ecosystems. In recent years, advanced oxidation technologies based on persulfate (PS) (PS-AOPs) have attracted widespread attention from researchers in the field of remediation of recalcitrant organic pollutants due to their advantages such as wide pH adaptability, ease of operation, and high reaction efficiency.

[0003] Heterogeneous catalysts based on transition metals have been extensively studied in persulfate activation due to their rapid reaction rates and mild operating conditions. In particular, transition metal nanoparticles with high specific surface areas and unique electronic structures can effectively increase the number of active sites and modulate intrinsic catalytic activity, thereby significantly promoting the persulfate activation process. However, these nanoparticles are prone to aggregation during preparation, and the synthesis cycle is usually long, posing challenges for their application. Furthermore, the dissolution of metal ions is significant during long-term operation, which may not only lead to catalyst deactivation and shorten its lifespan but also cause secondary heavy metal pollution, severely restricting its large-scale application.

[0004] To address this, some researchers have focused on anchoring metal nanoparticles through support loading and surface modification. Among these, in-situ anchoring of active metal components using polymerization strategies has proven to be a promising approach. Chen et al. (Chen, LK, et al. Nitrogen-doped porous carbon encapsulating iron nanoparticles for enhanced sulfathiazole removal via peroxymonosulfate activation. Chemosphere. 2020, 250, 126300) prepared a nitrogen-doped porous carbon-encapsulated iron nanoparticle catalyst for activating peroxymonosulfate (PMS) using a polymerization strategy, exhibiting good stability, but the preparation time required was 4 h. Jiao et al. (Jiao, J., et al. Insitu highly dispersed loading of molybdenum dioxide with oxygen vacancies on N-doped graphene for enhanced oxidative desulfurization of fuel oil. Journal of Environmental Chemical Engineering. 2023, 11, 109402) anchored molybdenum dioxide (MoO2) nanoparticles onto nitrogen-doped reduced graphene oxide via aniline polymerization, but the synthesis process took as long as 24 hours. Therefore, traditional polymerization processes often suffer from low mass transfer efficiency, leading to long polymerization times (often several to tens of hours) and uneven anchoring of active components.

[0005] Hypergravity technology is an emerging process intensification technique in chemical engineering, primarily simulating a hypergravity environment through high-speed rotating packing material in a rotating packed bed (RPB). In an RPB, the liquid is broken into smaller films or droplets, and rapid surface renewal effectively increases the liquid-solid interface area. Maintaining a high concentration gradient at the interface reduces external diffusion resistance, thereby enhancing mass transfer rates and mixing efficiency, and significantly shortening reaction time. Patent CN113893874A discloses a hypergravity-based batch preparation method for supported Mn-based catalysts and its application. This method uses ZSM-5 as a support and a manganese and iron nitrate solution as an impregnation liquid. Under hypergravity, the impregnation liquid is sprayed onto the surface of ZSM-5, and finally, the catalyst is obtained by high-temperature calcination. However, the active metal component in the catalyst prepared by this method is relatively large, and the interaction between the metal and the support is weak, limiting its catalytic activity and stability.

[0006] Therefore, developing a supergravity preparation method for polymerized anchored metal nanoparticles and combining the prepared catalyst with persulfate advanced oxidation technology is of great significance for providing a theoretical basis and technical support for the treatment of organic wastewater. Summary of the Invention

[0007] The purpose of this invention is to provide a supergravity preparation method for polymer-anchored metal nanoparticle catalysts and its application, which can uniformly distribute metal nanoparticles in a support and greatly shorten the preparation time of the catalyst.

[0008] The present invention adopts the following technical solution: A method for preparing polymerized anchored metal nanoparticle catalysts under ultragravity includes the following steps: S1. After cleaning and drying the carrier, load it into the rotating packed bed; S2. Add aniline monomer, oxidant and metal salt to acidic solution to prepare mixed reaction solution, and place it in storage tank for later use; S3. The mixed reaction solution is pumped to the rotating packed bed by a centrifugal pump. The rotating packed bed is started. Under the high gravity environment, the high-speed rotating packing shears the mixed reaction solution into fine liquid filaments and thin liquid films, so that it can make efficient contact with the carrier. During this process, aniline monomers polymerize into polyaniline and simultaneously anchor the metal salt onto the carrier, thus obtaining a carrier with polymerized and anchored metal active components. The reacted solution flows into the storage tank and is circulated. S4. After the reaction is complete, the carrier containing the polymerized anchored metal active component is removed and dried in a vacuum drying oven; after drying, it is calcined at high temperature under nitrogen protection to obtain a catalyst with uniformly dispersed metal nanoparticles.

[0009] Further, in S1, the carrier includes any one of activated carbon, alumina, and molecular sieve; the loading amount of the carrier is 30-60g.

[0010] Furthermore, in S2, the acidic solution includes any one of hydrochloric acid, acetic acid, sulfuric acid, and nitric acid.

[0011] Furthermore, in S2, the oxidant includes any one of ammonium sulfate, hydrogen peroxide, and sodium hypochlorite.

[0012] Furthermore, in S2, the metal salt includes any one of Co, Fe, Mn, Cu, Zn, and Ni salts.

[0013] Further, in S2, the concentration of the acidic solution is 0.5-3 mol / L, the concentration of the metal salt is 0.05-0.2 mol / L, the molar ratio of aniline monomer to oxidant is 1:1-1:3, and the volume of the mixed reaction solution is 0.5-2 L.

[0014] Furthermore, in S3, the hypergravity factor of the rotating packing bed is 10-50.

[0015] Furthermore, in S3, the flow rate of the mixed reaction solution is 500-1500 mL / min.

[0016] Furthermore, in S3, the circulation reaction time of the rotating packed bed is 30-120 min.

[0017] Furthermore, in S4, the drying temperature is 70℃ and the drying time is 12h; the calcination heating rate is 5℃ / min, the calcination temperature is 300-900℃, and the calcination time is 2-6h.

[0018] The catalyst is used to activate persulfate to remove organic pollutants from water, and the steps are as follows: (1) Weigh a measured amount of the prepared catalyst and add it to the prepared organic wastewater. Then place it on a magnetic stirrer and stir thoroughly to make the catalyst evenly dispersed. The volume of the organic wastewater is 100-1000 mL, the concentration of pollutants in the organic wastewater is 50-100 mg / L, and the initial pH of the organic wastewater is 3-11. The amount of catalyst added is 0.1-1.0 g. (2) After the system is mixed evenly, add the oxidant persulfate to initiate the catalytic reaction; the concentration of the persulfate is 0.5-3.0 mM and the reaction time is 30-90 min.

[0019] The beneficial effects of this invention are as follows: 1. This invention utilizes a high-gravity rotating packed bed as its core equipment. The high-speed rotating packing material breaks the liquid into tiny liquid micro-elements, which greatly enhances the mass transfer process, allowing the oxidant and aniline to mix thoroughly. This, in turn, promotes the rapid polymerization of aniline and anchors the active metal component. This process is distinctly different from the continuous liquid phase in traditional stirred reactors. The highly dispersed and micro-elemental liquid improves mass transfer rate and mixing efficiency, shortening catalyst preparation time by enhancing the polymerization process. This invention effectively solves the technical bottleneck of long catalyst preparation time in traditional reactors and has significant potential for large-scale production.

[0020] 2. The rapidly rotating packing in this invention changes the state of the carrier in a traditional reactor. The rapid renewal of the carrier surface can not only maintain a high concentration gradient at the interface to reduce external diffusion resistance, but also effectively prevent the occurrence of dead contact zones, so that the active components are uniformly polymerized and anchored in the carrier.

[0021] 3. The metal nanoparticle catalyst prepared by this invention exhibits excellent catalytic performance in the persulfate advanced oxidation system, and can efficiently degrade organic pollutants completely and efficiently in a short time, showing good application prospects in the field of organic wastewater treatment. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the rotating packed bed used in this invention; in the figure: 1-rotating packed bed; 2-motor; 3-liquid storage tank; 4-centrifugal pump; 5-flow meter; Figure 2 (a) is a scanning electron microscope (SEM) image of the catalyst RPB-C7 prepared in Example 7; (b) is a transmission electron microscope (TEM) image of RPB-C7; (c) is a high-resolution transmission electron microscope (HRTEM) image of RPB-C7; (d) is a SEM image of the catalyst MS-C3 prepared in Comparative Example 3; (e) is a TEM image of MS-C3; and (f) is an HRTEM image of MS-C3. Figure 3 X-ray diffraction (XRD) patterns of activated carbon, the catalyst PRB-C7 prepared in Example 7, and the material Co-PANI / AC-RPB prepared in Example 9; Figure 4 N2 adsorption-desorption isotherms for activated carbon and PRB-C7 prepared in Example 7; Figure 5 The catalysts prepared in Examples 1-4 demonstrate the efficiency of PMS in degrading phenol. Figure 6 The catalysts prepared in Examples 5-8 and Comparative Examples 1-4 demonstrate the efficiency of PMS in activating the degradation and mineralization of phenol. Figure 7 The catalyst prepared in Example 7 was used five times to test the degradation efficiency of phenol. Detailed Implementation

[0023] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] The rotor of the supergravity rotating packing bed used in this invention has an inner diameter of 30-50 mm, an outer diameter of 90-120 mm, and a height of 60-90 mm.

[0025] Example 1 A mixed reaction solution was prepared by adding aniline, an oxidant, and cobalt chloride hexahydrate to a 1 mol / L hydrochloric acid solution. 500 mL of this solution was placed in a storage tank, with aniline and hydrogen peroxide concentrations both at 0.2 mol / L, and cobalt ion concentration at 0.2 mol / L. Activated carbon was washed clean of dust and dried before being loaded into a rotating packed bed with a loading of 30 g. A centrifugal pump was then started to pump the mixture into the rotating packed bed at a flow rate of 800 mL / min, with the hypergravity factor β set to 20. Under the action of the high-speed rotating packing, the solution was broken down into micro-elements, achieving aniline polymerization and anchoring the metal active component. The reaction was stopped after 60 min, and the solid product was separated and dried in a vacuum drying oven at 70 ℃ for 12 h. The dried catalyst was then calcined at high temperature under nitrogen protection at a heating rate of 5 ℃ / min, a calcination temperature of 900 ℃, and a calcination time of 4 h. The final catalyst was named RPB-C1.

[0026] Example 2 A mixed reaction solution was prepared by adding aniline, an oxidant, and cobalt chloride hexahydrate to a 1 mol / L hydrochloric acid solution. 500 mL of this solution was placed in a storage tank, with aniline and hydrogen peroxide concentrations both at 0.2 mol / L, and cobalt ion concentration at 0.2 mol / L. Activated carbon was washed clean of dust and dried before being loaded into a rotating packed bed with a loading of 30 g. A centrifugal pump was then started to pump the mixture into the rotating packed bed at a flow rate of 800 mL / min, with the hypergravity factor β set to 30. Under the action of the high-speed rotating packing, the solution was broken down into micro-elements, achieving aniline polymerization and anchoring the active metal component. The reaction was stopped after 60 min, and the solid product was separated and dried in a vacuum drying oven at 70 ℃ for 12 h. The dried catalyst was then calcined at high temperature under nitrogen protection at a heating rate of 5 ℃ / min, a calcination temperature of 900 ℃, and a calcination time of 4 h. The final catalyst was named RPB-C2.

[0027] Example 3 A mixed reaction solution was prepared by adding aniline, an oxidant, and cobalt chloride hexahydrate to a 1 mol / L hydrochloric acid solution. 500 mL of this solution was placed in a storage tank, with aniline and hydrogen peroxide concentrations both at 0.2 mol / L, and cobalt ion concentration at 0.2 mol / L. Activated carbon was washed clean of dust and dried before being loaded into a rotating packed bed with a loading of 30 g. A centrifugal pump was then started to pump the mixture into the rotating packed bed at a flow rate of 800 mL / min, with the hypergravity factor β set to 40. Under the action of the high-speed rotating packing, the solution was broken down into micro-elements, achieving aniline polymerization and anchoring the metal active component. The reaction was stopped after 60 min, and the solid product was separated and dried in a vacuum drying oven at 70 ℃ for 12 h. The dried catalyst was then calcined at high temperature under nitrogen protection at a heating rate of 5 ℃ / min, a calcination temperature of 900 ℃, and a calcination time of 4 h. The final catalyst was named RPB-C3.

[0028] Example 4 A mixed reaction solution was prepared by adding aniline, an oxidant, and cobalt chloride hexahydrate to a 1 mol / L hydrochloric acid solution. 500 mL of this solution was placed in a storage tank, with aniline and hydrogen peroxide concentrations both at 0.2 mol / L, and cobalt ion concentration at 0.2 mol / L. Activated carbon was washed clean of dust and dried before being loaded into a rotating packed bed with a loading of 30 g. A centrifugal pump was then started to pump the mixture into the rotating packed bed at a flow rate of 800 mL / min, with the hypergravity factor β set to 50. Under the action of the high-speed rotating packing, the solution was broken down into micro-elements, achieving aniline polymerization and anchoring the active metal component. The reaction was stopped after 60 min, and the solid product was separated and dried in a vacuum drying oven at 70 ℃ for 12 h. The dried catalyst was then calcined at high temperature under nitrogen protection at a heating rate of 5 ℃ / min, a calcination temperature of 900 ℃, and a calcination time of 4 h. The final catalyst was named RPB-C4.

[0029] Example 5 A mixed reaction solution was prepared by adding aniline, an oxidant, and cobalt chloride hexahydrate to a 1 mol / L hydrochloric acid solution. 500 mL of this solution was placed in a storage tank, with aniline and hydrogen peroxide concentrations both at 0.2 mol / L, and cobalt ion concentration at 0.2 mol / L. Activated carbon was washed clean of dust and dried before being loaded into a rotating packed bed with a loading of 30 g. A centrifugal pump was then started to pump the mixture into the rotating packed bed at a flow rate of 1000 mL / min, with the hypergravity factor β set to 40. Under the action of the high-speed rotating packing, the solution was broken down into micro-elements, achieving aniline polymerization and anchoring the metal active component. The reaction was stopped after 30 min, and the solid product was separated and dried in a vacuum drying oven at 70 ℃ for 12 h. The dried catalyst was then calcined at high temperature under nitrogen protection at a heating rate of 5 ℃ / min, a calcination temperature of 900 ℃, and a calcination time of 4 h. The final catalyst was named RPB-C5.

[0030] Example 6 A mixed reaction solution was prepared by adding aniline, an oxidant, and cobalt chloride hexahydrate to a 1 mol / L hydrochloric acid solution. 500 mL of this solution was placed in a storage tank, with aniline and hydrogen peroxide concentrations both at 0.2 mol / L, and cobalt ion concentration at 0.2 mol / L. Activated carbon was washed clean of dust and dried before being loaded into a rotating packed bed with a loading of 30 g. A centrifugal pump was then started to pump the mixture into the rotating packed bed at a flow rate of 1000 mL / min, with the hypergravity factor β set to 40. Under the action of the high-speed rotating packing, the solution was broken down into micro-elements, achieving aniline polymerization and anchoring the metal active component. The reaction was stopped after 45 min, and the solid product was separated and dried in a vacuum drying oven at 70 ℃ for 12 h. The dried catalyst was then calcined at high temperature under nitrogen protection at a heating rate of 5 ℃ / min, a calcination temperature of 900 ℃, and a calcination time of 4 h. The final catalyst was named RPB-C6.

[0031] Example 7 A mixed reaction solution was prepared by adding aniline, an oxidant, and cobalt chloride hexahydrate to a 1 mol / L hydrochloric acid solution. 500 mL of this solution was placed in a storage tank, with aniline and hydrogen peroxide concentrations both at 0.2 mol / L, and cobalt ion concentration at 0.2 mol / L. Activated carbon was washed clean of dust and dried before being loaded into a rotating packed bed with a loading of 30 g. A centrifugal pump was then started to pump the mixture into the rotating packed bed at a flow rate of 1000 mL / min, with the hypergravity factor β set to 40. Under the action of the high-speed rotating packing, the solution was broken down into micro-elements, achieving aniline polymerization and anchoring the metal active component. The reaction was stopped after 60 min, and the solid product was separated and dried in a vacuum drying oven at 70 ℃ for 12 h. The dried catalyst was then calcined at high temperature under nitrogen protection at a heating rate of 5 ℃ / min, a calcination temperature of 900 ℃, and a calcination time of 4 h. The final catalyst was named RPB-C7.

[0032] Example 8 A mixed reaction solution was prepared by adding aniline, an oxidant, and cobalt chloride hexahydrate to a 1 mol / L hydrochloric acid solution. 500 mL of this solution was placed in a storage tank, with aniline and hydrogen peroxide concentrations both at 0.2 mol / L, and cobalt ion concentration at 0.2 mol / L. Activated carbon was washed clean of dust and dried before being loaded into a rotating packed bed with a loading of 30 g. A centrifugal pump was then started to pump the mixture into the rotating packed bed at a flow rate of 1000 mL / min, with the hypergravity factor β set to 40. Under the action of the high-speed rotating packing, the solution was broken down into micro-elements, achieving aniline polymerization and anchoring the metal active component. The reaction was stopped after 75 min, and the solid product was separated and dried in a vacuum drying oven at 70 ℃ for 12 h. The dried catalyst was then calcined at high temperature under nitrogen protection at a heating rate of 5 ℃ / min, a calcination temperature of 900 ℃, and a calcination time of 4 h. The final catalyst was named RPB-C8.

[0033] Example 9 A mixed reaction solution was prepared by adding aniline, an oxidant, and cobalt chloride hexahydrate to a 1 mol / L hydrochloric acid solution. 500 mL of this solution was placed in a storage tank, with aniline and hydrogen peroxide concentrations both at 0.2 mol / L, and cobalt ion concentration at 0.2 mol / L. Activated carbon was washed clean of dust and dried before being loaded into a rotating packed bed with a loading of 30 g. A centrifugal pump was then started, and the mixture was pumped into the rotating packed bed at a flow rate of 1000 mL / min, with the hypergravity factor β set to 40. Under the action of the high-speed rotating packing, the solution was broken down into micro-elements, achieving aniline polymerization and anchoring the active metal component. The reaction was stopped after 60 min, and the solid product was separated and dried in a vacuum drying oven at 70 ℃ for 12 h. The final material was named Co-PANI / AC-RPB.

[0034] Comparative Example 1 A mixed reaction solution was prepared by adding aniline, an oxidant, and cobalt chloride hexahydrate to a 1 mol / L hydrochloric acid solution. 500 mL of this solution was placed in a 1 L beaker, with aniline and hydrogen peroxide concentrations both at 0.2 mol / L, and cobalt ion concentration at 0.2 mol / L. 30 g of activated carbon was washed clean of surface dust, dried, and then placed in a beaker containing 500 mL of the mixed solution. The reaction was carried out under magnetic stirring (MS) at 800 r / min for 60 min, then stopped. The solid product was separated and dried in a vacuum drying oven at 70 ℃ for 12 h. The dried catalyst was then calcined at a high temperature under nitrogen protection at a heating rate of 5 ℃ / min, a calcination temperature of 900 ℃, and a calcination time of 4 h. The final catalyst was named MS-C1.

[0035] Comparative Example 2 A mixed reaction solution was prepared by adding aniline, an oxidant, and cobalt chloride hexahydrate to a 1 mol / L hydrochloric acid solution. 500 mL of this solution was placed in a 1 L beaker, with aniline and hydrogen peroxide concentrations both at 0.2 mol / L, and cobalt ion concentration at 0.2 mol / L. 30 g of activated carbon, after washing and drying to remove surface dust, was placed in the beaker containing the 500 mL mixed solution. The reaction was carried out under magnetic stirring at 800 r / min for 180 min, then stopped. The solid product was separated and dried in a vacuum drying oven at 70 ℃ for 12 h. The dried catalyst was then calcined at 900 ℃ for 4 h under nitrogen protection at a heating rate of 5 ℃ / min. The final catalyst was named MS-C2.

[0036] Comparative Example 3 A mixed reaction solution was prepared by adding aniline, an oxidant, and cobalt chloride hexahydrate to a 1 mol / L hydrochloric acid solution. 500 mL of this solution was placed in a 1 L beaker, with aniline and hydrogen peroxide concentrations both at 0.2 mol / L, and cobalt ion concentration at 0.2 mol / L. 30 g of activated carbon, after washing and drying to remove surface dust, was placed in the beaker containing the 500 mL mixed solution. The reaction was carried out under magnetic stirring at 800 r / min for 360 min, then stopped. The solid product was separated and dried in a vacuum drying oven at 70 ℃ for 12 h. The dried catalyst was then calcined at 900 ℃ for 4 h under nitrogen protection at a heating rate of 5 ℃ / min. The final catalyst was named MS-C3.

[0037] Comparative Example 4 A mixed reaction solution was prepared by adding aniline, an oxidant, and cobalt chloride hexahydrate to a 1 mol / L hydrochloric acid solution. 500 mL of this solution was placed in a 1 L beaker, with aniline and hydrogen peroxide concentrations both at 0.2 mol / L, and cobalt ion concentration at 0.2 mol / L. 30 g of activated carbon, after washing and drying to remove surface dust, was placed in a beaker containing 500 mL of the mixed solution. The reaction was carried out under magnetic stirring at 800 r / min for 720 min, then stopped. The solid product was separated and dried in a vacuum drying oven at 70 ℃ for 12 h. The dried catalyst was then calcined at 900 ℃ for 4 h under nitrogen protection at a heating rate of 5 ℃ / min. The final catalyst was named MS-C4.

[0038] Application examples were tested by activating persulfate to degrade the organic pollutant phenol using the prepared catalyst. All experiments were conducted in 200 mL beakers, and the reaction system was continuously stirred at 500 r / min under the control of a magnetic stirrer.

[0039] Experimental Example 1 First, 0.5 g of the catalysts prepared in Examples 1-4 were added to 100 mL of phenol solution with an initial concentration of 50 mg / L. Then, PMS was added to trigger the reaction at an initial concentration of 1.25 mM, and the reaction proceeded for 30 min. During the reaction, 2 mL samples were taken at specific time intervals (1, 3, 5, 7, 9, 15, 20, and 30 min) and immediately filtered through a 0.22 μm filter. Finally, the phenol concentration of the filtrate was analyzed using high-performance liquid chromatography (HPLC), and the results are shown below. Figure 5 As shown.

[0040] Experimental Example 2 First, 0.5 g of the catalysts prepared in Examples 5-8 and Comparative Examples 1-4 were added to 100 mL of phenol solution with an initial concentration of 50 mg / L. Then, PMS solution with an initial concentration of 1.25 mM was added to initiate the reaction. After 10 min of reaction, a 2 mL sample was taken and immediately filtered through a 0.22 μm filter. Finally, the phenol concentration of the filtrate was analyzed by high-performance liquid chromatography (HPLC), and the results are as follows: Figure 6 As shown.

[0041] Experimental Example 3 First, 0.5 g of the catalysts prepared in Examples 5-8 and Comparative Examples 1-4 were added to 100 mL of phenol solution with an initial concentration of 50 mg / L. Then, PMS solution with an initial concentration of 1.25 mM was added to initiate the reaction. After 30 min of reaction, a 2 mL sample was taken and immediately filtered through a 0.22 μm filter. Finally, the total organic carbon in the filtrate was analyzed using a total organic carbon analyzer. The results are as follows: Figure 6 As shown.

[0042] Figure 1 This is a schematic diagram of the rotating packed bed used in this invention. First, cleaned activated carbon is loaded into the rotating packed bed, and aniline, an oxidant, and a metal salt are added to an acidic solution to prepare a mixed reaction solution. Then, a centrifugal pump is started to deliver the mixture to the rotating packed bed at a certain flow rate, and a hypergravity factor is set. Under the action of the high-speed rotating packing, the solution is cut into micro-elements, realizing aniline polymerization and anchoring the metal active component. After a certain reaction time, the reaction is stopped, the solid product is separated, and the catalyst, dried in a vacuum drying oven, is calcined at high temperature in a tube furnace to obtain the catalyst material.

[0043] Figure 2 (a) Scanning electron microscope (SEM) image of catalyst RPB-C7 prepared in Example 7; (b) Transmission electron microscope (TEM) image of RPB-C7; (c) High-resolution transmission electron microscope (HRTEM) image of RPB-C7. (d) SEM image of catalyst MS-C3 prepared in Comparative Example 3; (e) TEM image of MS-C3; (f) HRTEM image of MS-C3. The results show that SEM reveals a near-spherical stacked morphology on the surfaces of both RPB-C7 and MS-C3, but RPB-C7 exhibits a rougher surface and more abundant interstitial spaces. TEM indicates that MS-C3 exhibits a dispersed structure compared to RPB-C7, demonstrating that the aniline polymerization reaction was not fully completed in the magnetically stirred reactor due to limited mass transfer. HRTEM showed that in RPB-C7, metallic cobalt was mainly anchored on the carrier surface in the form of small cobalt nanoparticles, and the size of the nanoparticles in RPB-C7 was much smaller than that in MS-C3. This indicates that the strong mixing and mass transfer efficiency in RPB enabled aniline to fully polymerize and uniformly disperse the active metal component. However, the insufficient polymerization of aniline in the magnetically stirred reactor resulted in poor dispersion of cobalt nanoparticles and agglomeration.

[0044] Figure 3X-ray diffraction (XRD) patterns of activated carbon, the catalyst PRB-C7 prepared in Example 7, and the material Co-PANI / AC-RPB prepared in Example 9 are shown. The results indicate that Co-PANI / AC-RPB exhibits three significant characteristic peaks of PANI at 15.2°, 19.0°, and 25.8°, strongly suggesting that aniline monomers polymerize on the AC surface to form PANI. After high-temperature calcination, two more characteristic peaks appear at 23.3° and 44.5°, corresponding to the (002) and (100) crystals of graphite carbon, respectively. More importantly, RPB-C7 exhibits three significant characteristic peaks at 44.5°, 51.2°, and 75.6°, corresponding to the Co-PANI / AC-RPB material prepared in Example 9. 0 (PDF#15-0806) has (111), (200) and (220) crystal planes, which proves the existence of metallic cobalt.

[0045] Figure 4 The N2 adsorption-desorption isotherms are shown for activated carbon and PRB-C7 prepared in Example 7. The results indicate that the specific surface area of ​​PRB-C7 is 1284.1 μm. 2 g -1 This is greater than AC (988.8 m). 2 g -1 This indicates that the catalyst prepared by polymerization anchoring can effectively improve its specific surface area.

[0046] Figure 5 The efficiency of the catalysts prepared in Examples 1-4 in activating PMS for phenol degradation is shown. The results indicate that as β increases to 40, the degradation rate of phenol gradually increases; however, when β further increases, the degradation rate decreases. At β=20, the packing material exhibits weak shear force on the liquid, leading to incomplete aniline polymerization and poor anchoring of the active component AC on the surface, resulting in unsatisfactory catalytic performance. Increasing the β value helps enhance liquid-solid mass transfer efficiency and increase the contact area, thereby allowing more active components to polymerize and anchor on the AC surface. However, it should be noted that as β continues to increase, the residence time of the precursor solution in the packing material shortens, reducing the effective contact time between the active component and AC, thus decreasing catalytic performance.

[0047] Figure 6 The catalysts prepared in Examples 5-8 and Comparative Examples 1-4 were used to activate the degradation and mineralization efficiency of PMS for phenol. The results showed that the performance of catalyst RPB-C7, which can be prepared in only 1 h in RPB, is comparable to that of catalyst MS-C3, which requires 6 h to prepare in a conventional magnetically stirred reactor, and the preparation time is shortened by 6 times.

[0048] Figure 7The degradation efficiency of phenol by the RPB-C7 catalyst prepared in Example 7 after 5 cycles was evaluated. The results showed that RPB-C7 could still achieve complete degradation of phenol after 5 cycles, indicating its good stability.

[0049] Matters not covered in this invention are common knowledge. Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this invention, and not to limit it; although the invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this invention.

Claims

1. A method for preparing polymerized anchored metal nanoparticle catalysts under ultragravity, characterized in that: Includes the following steps: S1. After cleaning and drying the carrier, load it into the rotating packed bed; S2. Add aniline monomer, oxidant and metal salt to acidic solution to prepare mixed reaction solution, and place it in storage tank for later use; S3. The mixed reaction solution is pumped to the rotating packed bed by a centrifugal pump. The rotating packed bed is started. Under the high gravity environment, the high-speed rotating packing shears the mixed reaction solution into fine liquid filaments and thin liquid films, so that it can make efficient contact with the carrier. During this process, aniline monomers polymerize into polyaniline and simultaneously anchor the metal salt onto the carrier, thus obtaining a carrier with polymerized and anchored metal active components. The reacted solution flows into the storage tank and is circulated. S4. After the reaction is complete, the carrier containing the polymerized anchored metal active component is removed and dried in a vacuum drying oven; after drying, it is calcined at high temperature under nitrogen protection to obtain a catalyst with uniformly dispersed metal nanoparticles.

2. The method for preparing a polymerized anchored metal nanoparticle catalyst under ultragravity according to claim 1, characterized in that: In S1, the carrier includes any one of activated carbon, alumina, and molecular sieve; the loading amount of the carrier is 30-60g.

3. The method for preparing a polymerized anchored metal nanoparticle catalyst under ultragravity according to claim 1, characterized in that: In S2, the acidic solution includes any one of hydrochloric acid, acetic acid, sulfuric acid, and nitric acid; the oxidizing agent includes any one of ammonium sulfate, hydrogen peroxide, and sodium hypochlorite.

4. The method for preparing a polymerized anchored metal nanoparticle catalyst under ultragravity according to claim 1, characterized in that: In S2, the metal salt includes any one of Co, Fe, Mn, Cu, Zn, and Ni salts.

5. The method for preparing a polymerized anchored metal nanoparticle catalyst under ultragravity according to claim 1, characterized in that: In S2, the concentration of the acidic solution is 0.5-3 mol / L, the concentration of the metal salt is 0.05-0.2 mol / L, the molar ratio of aniline monomer to oxidant is 1:1-1:3, and the volume of the mixed reaction solution is 0.5-2 L.

6. The method for preparing a polymerized anchored metal nanoparticle catalyst under ultragravity according to claim 1, characterized in that: In S3, the hypergravity factor of the rotating packing bed is 10-50.

7. The method for preparing a polymerized anchored metal nanoparticle catalyst under ultragravity according to claim 1, characterized in that: In S3, the flow rate of the mixed reaction solution is 500-1500 mL / min.

8. The method for preparing a polymerized anchored metal nanoparticle catalyst under ultragravity according to claim 1, characterized in that: In S3, the circulation reaction time of the rotating packed bed is 30-120 min.

9. The method for preparing a polymerized anchored metal nanoparticle catalyst under ultragravity according to claim 1, characterized in that: In S4, the drying temperature is 70℃ and the drying time is 12h; the calcination heating rate is 5℃ / min, the calcination temperature is 300-900℃, and the calcination time is 2-6h.

10. A catalyst prepared by the method according to any one of claims 1-9 is used to activate persulfate to remove organic pollutants from water.

Images