Aluminum oxide foamed ceramic loaded iron-cobalt bimetallic catalyst as well as preparation method and application thereof

Abstract

The invention discloses an aluminum oxide foamed ceramic loaded iron-cobalt bimetallic catalyst as well as a preparation method and application thereof. The catalyst is prepared by mixing alumina powder with a solution containing ferrous salt, cobalt salt and a complexing agent, carrying out a load reaction to obtain alumina powder loaded with an iron-cobalt precursor, and sequentially carrying out oxidation-reduction roasting, curing molding and sintering on the alumina powder loaded with the iron-cobalt precursor. The catalyst is high in activity, rich in porosity, high in specific surface area, stable in performance and long in service life, can efficiently catalyze ozone to deeply oxidize Tl < + >, and effectively solves the problem of treatment of wastewater containing heavy metal thallium.

Description

Technical Field

[0001] This invention relates to an iron-cobalt catalyst, specifically to an iron-cobalt bimetallic catalyst supported on alumina foam ceramic, and also to its preparation method and application, belonging to the fields of catalyst preparation and heavy metal wastewater treatment. Background Technology

[0002] The emission of thallium and its compounds has become a pollution problem with serious environmental risks and health threats. As a highly toxic and easily migrating trace metal, thallium occurs in the environment primarily in its monovalent form (Tl). + Thallium, primarily composed of thallium, is highly water-soluble and has weak adsorption properties, making it prone to long-distance migration in water bodies. It enters the food chain through bioaccumulation, ultimately posing multiple threats to ecosystems and human health. Despite this, thallium's unique physicochemical properties play an irreplaceable role in several industrial sectors. For example, the electronics industry widely uses thallium bromide (TlBr) as a key material for high-performance infrared semiconductors and scintillation crystals; the specialty glass manufacturing industry relies on thallium oxide (Tl₂O₃) to improve glass refractive index, manufacturing optical fibers and high-end optical lenses; and in non-ferrous metal smelting (such as zinc, lead, and copper smelting), thallium dissolves from ores as a by-product, forming high-concentration thallium-containing wastewater. Current treatment processes, such as conventional coagulation sedimentation, sulfidation, or activated carbon adsorption, are ineffective against thallium. + Its removal efficiency is limited and its selectivity is poor; it is susceptible to coexisting cations (such as K+). + Na + The strong interference makes it difficult to stably reduce the concentration to below the stringent emission limits of μg / L. Its fundamental flaw lies in Tl. + Its chemical behavior is similar to that of alkali metal ions, lacking the properties of easy precipitation or complexation. Therefore, Tl... + Deep oxidation to trivalent thallium (Tl) 3+ ) is the key and prerequisite for achieving efficient removal. Tl 3+ Thallium readily hydrolyzes to form Tl(OH)3, which has extremely low solubility, or forms a strong complex that is efficiently captured by adsorbents. Achieving valence state transformation of the heavy metal thallium through various advanced oxidation processes (AOPs) not only overcomes the removal bottlenecks of traditional methods but is also a necessary condition for achieving deep thallium purification.

[0003] However, current common oxidative treatment processes for thallium-containing industrial wastewater suffer from drawbacks and shortcomings, including low oxidation efficiency, poor selectivity, low removal rate, high cost, and significant risk of secondary pollution. Therefore, deep oxidation of monovalent thallium in industrial wastewater is urgently needed in related wastewater treatment processes. Chinese patent CN116285996A discloses a bio-manganese oxide-based passivating agent for thallium pollution remediation, its preparation method, and remediation method. It prepares high-valent manganese oxides through microbial oxidation, which can effectively adsorb and oxidize thallium. However, its practical application is limited by difficulties in maintaining bacterial activity, process complexity, and insufficient long-term stability verification. Chinese patent CN115650402A discloses a piezoelectric-enhanced heterogeneous Fenton oxidation-adsorption method for treating thallium-containing wastewater. It utilizes piezoelectric material BiFeO3-enhanced heterogeneous Fenton oxidation-adsorption technology to treat thallium-containing wastewater. However, in practical applications, it may face problems such as high energy consumption, efficiency decline during catalyst recovery and regeneration, and potential secondary pollution risks.

[0004] Therefore, it is of great significance to develop a simple, low-cost, and efficient method for treating wastewater pollution caused by monovalent thallium ions. Summary of the Invention

[0005] To address the problems existing in the prior art, the first objective of this invention is to provide an iron-cobalt bimetallic catalyst supported on alumina foam ceramic. This catalyst exhibits high activity, strong stability, and a long service life.

[0006] A second objective of this invention is to provide a method for preparing an iron-cobalt bimetallic catalyst supported on alumina foam ceramic. This method is simple, low-cost, and suitable for industrial production.

[0007] A third objective of this invention is to provide an application of an iron-cobalt bimetallic catalyst supported on alumina foam ceramic. This catalyst can efficiently catalyze the ozone oxidation of Tl. + For Tl 3+ This enables the deep removal of monovalent thallium ions.

[0008] To achieve the above-mentioned technical objectives, the present invention provides a method for preparing an iron-cobalt bimetallic catalyst supported on alumina foam ceramic. The method involves mixing alumina powder with a solution containing ferrous salt, cobalt salt, and a complexing agent to undergo a loading reaction, obtaining alumina powder supported on an iron-cobalt precursor. The alumina powder supported on the iron-cobalt precursor is then subjected to sequential redox calcination to obtain alumina powder supported on iron-cobalt bimetallic nanoparticles. The alumina powder supported on iron-cobalt bimetallic nanoparticles is then mixed with a foaming agent and a binder to form a slurry, which is then solidified using a mold to obtain a porous gel. The porous gel is then sintered to obtain the final product.

[0009] The alumina foam ceramic spherical catalyst supported on iron-cobalt bimetals prepared in this invention successfully constructs a novel catalytic material with high activity (Fe-Co bimetallic nanoparticles), high stability (α-Al2O3 monolithic support), and ease of engineering use (regular spherical shape) through an innovative process combining "complexation-two-stage calcination" and "curing-sintering". Specifically, in the Fe-Co bimetallic system of this invention, the iron and cobalt are metallic or alloyed nanoparticles, and there is a significant electronic synergistic effect between Fe and Co. Co can optimize the electronic structure of Fe, greatly promoting the chain reaction of ozone decomposition to generate hydroxyl radicals (·OH), resulting in high catalytic activity. Through the "complexation-calcination" process, the size of the active metal component is controlled at the nanoscale and highly dispersed on the surface of the support, avoiding the problems of metal sintering and pore blockage caused by high loading, thereby exposing more active sites. This invention starts from the powder source, simultaneously forming the active component (FeCo nanoparticles) and the support (Al2O3) to prepare a spherical monolithic catalyst with uniform size.

[0010] As a preferred embodiment, the alumina powder undergoes surface washing to remove impurities and calcination activation pretreatment. Surface removal involves multiple washes with acetone, ethanol, and deionized water to remove surface impurities, followed by drying and high-temperature calcination at 500-800°C to activate the surface.

[0011] As a preferred embodiment, the molar ratio of the alumina powder to the metal elements in the ferrous and cobalt salts is 50-100:1.

[0012] As a preferred embodiment, the molar ratio of iron in the ferrous salt to cobalt in the cobalt salt is 1:1 to 3.

[0013] As a preferred embodiment, the ferrous salt includes at least one of ferrous acetate, ferrous sulfate, and ferrous chloride.

[0014] As a preferred embodiment, the cobalt salt includes at least one of cobalt nitrate, cobalt sulfate, and cobalt chloride.

[0015] As a preferred embodiment, the molar amount of the complexing agent is 2 to 4 times the total molar amount of the ferrous salt and the cobalt salt.

[0016] As a preferred embodiment, the complexing agent includes at least one of oxalic acid, citric acid, ethylenediaminetetraacetic acid, 2,2-bipyridine, and 1,10-phenanthroline.

[0017] As a preferred approach, the loading reaction process involves stirring the mixture at 60-90°C until the solvent evaporates completely.

[0018] As a preferred embodiment, the calcination is a two-stage calcination. The first stage calcination conditions are: an oxygen-containing atmosphere, a temperature of 250~400℃, and a time of 0.5~3h. The second stage calcination conditions are: a reducing atmosphere, a temperature of 600~900℃, more preferably 600~800℃, and a time of 1~4h, more preferably 2~4h. The two-stage calcination improves the overall performance of the catalyst. The first stage, low-temperature calcination in an oxygen-containing atmosphere, primarily removes organic matter adhering to the catalyst surface, while the second stage, high-temperature reducing calcination, mainly forms iron-cobalt bimetallic nanoparticles.

[0019] As a preferred embodiment, the oxygen-containing atmosphere is air.

[0020] As a preferred embodiment, the reducing atmosphere is a mixture of hydrogen and a protective gas. The hydrogen volume percentage is 5-10%. The protective gas includes at least one of nitrogen and an inert gas.

[0021] As a preferred embodiment, the amount of foaming agent added is 0.5~3.0 wt% of the alumina powder loaded with iron-cobalt bimetallic nanoparticles.

[0022] As a preferred embodiment, the amount of the binder added is 3.0~7.0 wt% of the alumina powder loaded with iron-cobalt bimetallic nanoparticles.

[0023] As a preferred embodiment, the foaming agent includes at least one of ammonium carbonate, ammonium bicarbonate, and azodicarbonamide.

[0024] As a preferred embodiment, the adhesive comprises at least one of polyvinyl alcohol, polyethylene glycol, and polyvinyl butyral.

[0025] As a preferred embodiment, the sintering conditions are: a protective atmosphere, a temperature of 1200~1500℃, and a time of 2~4h.

[0026] As a preferred embodiment, the protective atmosphere includes at least one of nitrogen and an inert gas. The inert gas is preferably argon.

[0027] The present invention also provides an iron-cobalt bimetallic catalyst supported on alumina foam ceramic, which is prepared by the above method.

[0028] As a preferred embodiment, the diameter of the iron-cobalt bimetallic catalyst supported on the alumina foam ceramic is 5-8 mm. The size of the metal nanoparticles in the catalyst is 60-120 nm.

[0029] This invention also provides an application of an iron-cobalt bimetallic catalyst supported on alumina foam ceramic for catalytic ozone oxidation of Tl.+ For Tl 3+ Among them, ozone (O3) is catalyzed by iron-cobalt (Fe-Co) nanoparticles through the valence state cycle of metal ions (such as Co). 2+ / Co 3+ and Fe 2+ / Fe 3+ It efficiently decomposes and generates hydroxyl radicals (·OH). The process begins with the adsorption and activation of ozone on the catalyst surface, which generates superoxide radicals (O2·OH) through electron transfer. - ) and a high-valent metal-oxygen intermediate, the latter reacts with water to generate ·OH, which in turn triggers a chain reaction to achieve the proliferation of free radicals; the generated ·OH acts as a strong oxidant, and through an electron transfer mechanism, it transfers monovalent thallium (Tl) + ) is oxidized to unstable divalent thallium (Tl) 2+ ),Tl 2+ It is further rapidly oxidized to trivalent thallium (Tl) by ·OH, ozone, or dissolved oxygen. 3+ ). Tl 3+ It is easily hydrolyzed in water to form Tl(OH)3 precipitate or is adsorbed and co-precipitated, thus realizing the removal of Tl from wastewater. + Highly efficient oxidative removal and partial Tl removal 3+ The removal of.

[0030] As a preferred embodiment, the catalyst is used for the catalytic oxidation of Tl in wastewater using ozone. + For Tl 3+ .

[0031] As a preferred embodiment, the catalyst dosage is 1 to 20 particles / L.

[0032] As a preferred embodiment, the ozone concentration is 2~20 mg / L.

[0033] As a preferred embodiment, the Tl + The initial concentration is 10~1000μg / L.

[0034] As a preferred embodiment, the wastewater is at room temperature and has a pH of 2-4.

[0035] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0036] (1) The iron-cobalt bimetallic catalyst supported on alumina foam ceramic of the present invention has high catalytic activity, stable structure, easy separation, recyclability and long service life.

[0037] (2) The catalyst of the present invention can efficiently catalyze the deep oxidation of Tl by ozone. + For Tl 3+ (Tl) 3+The amount of sludge produced by sedimentation is far less than that of traditional chemical sedimentation methods, achieving Tl in wastewater + The catalyst of this invention can also achieve deep oxidative removal of Tl. 3+ Adsorption removal greatly reduces the generation of solid hazardous waste and the potential risk of secondary pollution, and has a high oxidation removal rate, mild catalytic conditions, and is easy to apply;

[0038] (3) The catalyst is simple to prepare, low in cost, and suitable for industrial production. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0040] Figure 1 The images show a comparison of the appearance and microstructure of the FeCo / α-Al2O3 sphere catalyst prepared in Example 1, the α-Al2O3 sphere material prepared in Comparative Example 1, the Co / α-Al2O3 sphere material prepared in Comparative Example 2, and the Fe / α-Al2O3 sphere material prepared in Comparative Example 3. Specifically, (a) and (e) are the appearance and scanning electron microscope (SEM) images of the FeCo / α-Al2O3 sphere catalyst, respectively; (b) and (f) are the appearance and SEM images of the α-Al2O3 sphere material, respectively; (c) and (g) are the appearance and SEM images of the Co / α-Al2O3 sphere material, respectively; and (d) and (h) are the appearance and SEM images of the Fe / α-Al2O3 sphere material, respectively.

[0041] Figure 2 The catalyst of Example 1 and the materials prepared in each comparative example were used to catalyze ozone to react with Tl-containing substances. + Comparison of the effects of deep oxidation and adsorption removal on wastewater, where (a) represents the concentration of Ti in the wastewater. + The concentration change comparison chart (b) shows the comparison of the total thallium ion concentration in the wastewater after the oxidation process.

[0042] Figure 3 During the five-times recycling of the FeCo / α-Al2O3 sphere catalyst prepared in Example 1 of this invention, the catalytic effect of ozone on simulated Tl-containing... + Comparison chart showing the effects of deep oxidation treatment of wastewater.

[0043] Figure 4The FeCo / α-Al2O3 sphere catalyst prepared in Example 1 of this invention was used in five cycles for deep oxidation treatment of Tl-containing materials. + After wastewater treatment, the X-ray photoelectron spectroscopy characterization image of the catalyst surface is obtained.

[0044] Figure 5 To investigate the application of the FeCo / α-Al2O3 sphere catalyst prepared in Example 1 of this invention in a self-made acrylic cylindrical water treatment device to treat Tl-containing pollutants discharged from an actual semiconductor electronics factory in Hunan Province. + A simplified process diagram and effect diagram of wastewater oxidation via ozone catalytic oxidation.

[0045] Figure 6 The images show scanning electron microscope (SEM) images of the FeCo / α-Al2O3 sphere catalysts prepared by different reduction and calcination temperatures according to this invention.

[0046] Figure 7 This is a scanning electron microscope image of the FeCo / α-Al2O3 sphere catalyst prepared by different reduction and calcination times according to the present invention. Detailed Implementation

[0047] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments and accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.

[0048] Example 1

[0049] (1) Commercial alumina (α-Al2O3) was washed three times with acetone, ethanol and deionized water to remove surface impurities and calcined at 600°C for 2 hours to activate the surface; 1 g of α-Al2O3 was added to 20 ml of aqueous solution containing 0.05 mM ferrous sulfate heptahydrate and 0.1 mM cobalt nitrate hexahydrate, and 0.25 mM 2,2-bipyridine and 0.25 mM 1,10-phenanthroline were added. The mixture was stirred continuously at 80°C to evaporate water to obtain the precursor.

[0050] (2) The above precursor was oxidized and calcined in a tube furnace at 300°C for 2 hours by introducing air, and then reduced and calcined at 800°C for 3 hours by introducing a hydrogen-argon mixture (hydrogen volume percentage of 10%) to obtain alumina powder loaded with iron-cobalt bimetallic nanoparticles.

[0051] (3) The calcined powder (alumina powder loaded with iron-cobalt bimetallic nanoparticles), azodicarbonamide and polyethylene glycol were stirred and mixed in a mass ratio of 100:2:5. The resulting slurry was immediately injected into a rotating cylinder mold with a diameter of 8 mm to form gel spheres of uniform size. The gel spheres were then placed in a muffle furnace under argon protection and sintered at 1200°C for 2 hours to obtain an iron-cobalt bimetallic catalyst (FeCo / α-Al2O3 sphere) supported on alumina foam ceramic with a diameter of 8 mm.

[0052] Comparative Example 1

[0053] α-Al2O3 sphere material was prepared directly from commercial alumina (α-Al2O3) according to step (3) in Example 1.

[0054] Comparative Example 2

[0055] Co / α-Al2O3 sphere material was prepared using the method of Example 1, except that the mixed metal salt in step (1) was replaced with 0.15 mM single cobalt nitrate hexahydrate.

[0056] Comparative Example 3

[0057] Fe / α-Al2O3 sphere material was prepared using the method of Example 1, except that the mixed metal salt in step (1) was replaced with 0.15 mM single ferrous sulfate heptahydrate.

[0058] Figure 1The images show the appearance and scanning electron microscope (SEM) characterization of the catalyst material prepared in Example 1 of this invention and the materials prepared in Comparative Examples 1 to 3. Specifically, (a) and (e) are the appearance and SEM images of the FeCo / α-Al2O3 sphere catalyst prepared in Example 1, respectively; (b) and (f) are the appearance and SEM images of the α-Al2O3 sphere material, respectively; (c) and (g) are the appearance and SEM images of the Co / α-Al2O3 sphere material, respectively; and (d) and (h) are the appearance and SEM images of the Fe / α-Al2O3 sphere material, respectively. From the morphology, the FeCo / α-Al2O3 sphere catalyst prepared in this invention consists of single spherical particles with uniform size, ranging from 5 to 8 mm in diameter. The surface color of the particles is light gray, mainly due to the silvery-gray color caused by the iron and cobalt metal elements loaded on the particle surface. The alumina foam ceramic materials loaded with a single metal (Comparative Examples 2 and 3) also consist of single spherical particles with a light gray surface color, while the unloaded α-Al2O3 sphere (Comparative Example 1) has a white surface color (the color of the alumina powder itself). Further analysis of the microstructure of the materials using scanning electron microscopy images reveals… Figure 1 (b) shows that the bright particles on the surface of the FeCo / α-Al2O3 sphere catalyst of the present invention are iron-cobalt bimetallic nanoparticles with a particle size of 60~120 nm; the α-Al2O3 material in Comparative Example 1 has a smooth surface and a porous structure; the bright particles on the surface of the Co / α-Al2O3 sphere material in Comparative Example 2 are cobalt metal nanoparticles with a particle size of 100~300 nm; and the bright particles on the surface of the Fe / α-Al2O3 sphere material in Comparative Example 3 are iron metal nanoparticles with a particle size of 60~150 nm.

[0059] Example 2

[0060] The FeCo / α-Al2O3 sphere catalyst prepared in Example 1 of this invention was used to catalyze the reaction of ozone molecules generated by an ozone generator (NP020P-S-2) with heavy metals Tl in simulated wastewater. + Deep oxidation treatment was carried out, in which, at room temperature, the Tl in the simulated wastewater was reduced. + The concentration was 1000 μg / L, the volume of the reaction wastewater was 1 L, the pH value of the wastewater was 3.2, the ozone concentration was determined to be 5 mg / L by a gas phase ozone concentration detector, the amount of catalyst used was 20 pieces, the stirring rate was 600 rpm / min, and the reaction time was 10 minutes.

[0061] The catalysts described above were replaced with the materials prepared in Comparative Examples 1-3, and the above application experiments were conducted to compare the catalytic effects of different materials. Additionally, control experiments were conducted with either no catalyst added or no ozone production during the catalytic process. The results are shown in [Figure Number]. Figure 2 Where (a) is Tl in wastewater + The concentration change comparison chart (b) shows the comparison of the total thallium ion concentration in the wastewater after the oxidation process.

[0062] from Figure 2 As can be seen from (a), the FeCo / α-Al2O3 sphere / ozone of the present invention, the α-Al2O3 sphere / ozone of Comparative Example 1, the Co / α-Al2O3 sphere / ozone of Comparative Example 2, and the Fe / α-Al2O3 sphere / ozone of Comparative Example 3 correspond to 1000 μg / L Tl + Wastewater Tl within ten minutes + The residual concentrations were 0.02 μg / L, 788.15 μg / L, 178.28 μg / L, and 461.58 μg / L, respectively, corresponding to Tl + The oxidative removal efficiencies were 100%, 21.19%, 82.17%, and 53.84%, while the effects of catalyst alone (without ozone) or ozone alone (without catalyst) on Tl were... + The oxidative removal rate was significantly poor. Figure 2 (b) The results showed that FeCo / α-Al2O3 sphere / ozone, α-Al2O3 sphere / ozone, Co / α-Al2O3 sphere / ozone and Fe / α-Al2O3 sphere / ozone had different effects on the simulated Tl content of 1000 μg / L. + After a 10-minute reaction, the adsorption removal rates of the heavy metal thallium in the wastewater were 304.85, 103.54, 213.25, and 175.54 μg / L, respectively, indicating that the catalyst can effectively remove thallium. 3+ Adsorption removal is performed, and because the catalyst of this invention can completely remove Tl... + Oxidized to Tl 3+ Therefore, it has the highest adsorption and removal rate for thallium ions, while a single catalyst system or a single ozone system is basically unable to adsorb and remove thallium ions.

[0063] Example 3

[0064] The FeCo / α-Al2O3 sphere catalyst from Example 2 was directly separated and recovered, and then the Tl-containing material was catalytically oxidized again under the conditions of Example 2. + Wastewater experiments were conducted, with each cycle repeated 5 times. The catalytic effect of the catalyst is shown in [the table below]. Figure 3 .from Figure 3As can be seen, even after five consecutive cycles, the catalyst of this invention still exhibits high activity for Tl. + The oxidative removal efficiency reached over 99%.

[0065] X-ray photoelectron spectroscopy (XPS) analysis was performed on the FeCo / α-Al₂O₃ sphere catalyst of the present invention, which had thallium ions adsorbed on its surface after 5 cycles. The scanning orbital was the 4f electron orbital of Tl element, and the scanning range was from 115 to 135 eV. The results are shown in [Figure number missing]. Figure 4 .from Figure 4 As can be seen from the above, the thallium element adsorbed on the surface of the FeCo / α-Al2O3 sphere catalyst of the present invention after the reaction is mainly Tl. 3+ Tl + with Tl 3+ The content percentages were 3.56% and 96.44%, respectively.

[0066] Example 4

[0067] The FeCo / α-Al2O3 sphere catalyst prepared in Example 1 was used to treat the Tl-containing emissions from an actual semiconductor electronics factory in Hunan Province. + Wastewater undergoes small-scale deep oxidation treatment, in which wastewater Tl + The initial concentration was 486.24 μg / L, the single-batch wastewater treatment volume was 144 L, and the treatment time was 24 hours. FeCo / α-Al₂O₃ sphere catalyst was placed on the screen layer of an acrylic cylindrical water treatment device (inner diameter x height 100 x 400 mm), with a catalyst dosage of 50 particles. A micro / nano aeration disc (diameter 80 mm) was placed at the bottom of the water treatment device and connected to an ozone generator. The ozone concentration was determined to be 5 mg / L using a gas phase ozone concentration detector. (Contains Tl) + Wastewater is pumped into the device at a flow rate of 100 ml / min using a peristaltic pump. FeCo / α-Al₂O₃ sphere catalyst microspheres with a particle diameter of 8 mm are placed on the upper part of the screen layer. Ozone gas generated by the ozone generator is blown into the device through a nano-aeration disc. (The text also mentions Tl content, but the connection to the wastewater is unclear.) + Wastewater flows into the device from the lower end, with a theoretical retention time of approximately 30 minutes. The wastewater is then discharged from the top, and the post-reaction liquid is collected. A schematic diagram of the specific reaction treatment device is shown below. Figure 5 As shown in (a), the results of the oxidation removal effect are as follows: Figure 5 (b) , where timing begins after water exits from the top (0h). It can be seen that the acrylic cylindrical water treatment device containing the FeCo / α-Al2O3 sphere catalyst of this invention produces wastewater Tl within 24 hours of continuous operation. + The removal efficiency can still reach 98.12%.

[0068] Example 5

[0069] The method of Example 1 was used to prepare an iron-cobalt bimetallic catalyst supported on alumina foam ceramic, with the difference being that in step (2), the precursor was controlled to be reduced and calcined at 700℃ and 900℃ for 3h respectively.

[0070] The two catalyst materials obtained have similar compositions and structures to those in Example 1, and the corresponding electron micrographs are shown below. Figure 6 Among them, (a) is the catalyst prepared at a reduction calcination temperature of 700℃, and (b) is the catalyst prepared at a reduction calcination temperature of 900℃.

[0071] Example 6

[0072] The method of Example 1 was used to prepare an iron-cobalt bimetallic catalyst supported on alumina foam ceramic, with the difference being that in step (2), the precursor was controlled to be reduced and calcined at 800°C for 1 h and 4 h respectively.

[0073] The two catalyst materials obtained are similar to those in Example 1, and the corresponding electron micrographs are shown below. Figure 7 (a) is the catalyst obtained by reduction calcination for 1 hour, and (b) is the catalyst obtained by reduction calcination for 4 hours.

[0074] Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing an iron-cobalt bimetallic catalyst supported on alumina foam ceramic, characterized in that: Alumina powder is mixed with a solution containing ferrous salt, cobalt salt and complexing agent to carry out a loading reaction, thereby obtaining alumina powder loaded with iron-cobalt precursors; the alumina powder loaded with iron-cobalt precursors is subjected to redox calcination to obtain alumina powder loaded with iron-cobalt bimetallic nanoparticles; the alumina powder loaded with iron-cobalt bimetallic nanoparticles is then mixed with a foaming agent and a binder to form a slurry, which is then solidified by a mold to obtain a porous gel; the porous gel is then sintered to obtain the final product.

2. The method for preparing an iron-cobalt bimetallic catalyst supported on alumina foam ceramic according to claim 1, characterized in that: The molar ratio of the alumina powder to the metal elements in the ferrous and cobalt salts is 50-100:1; The molar ratio of iron in the ferrous salt to cobalt in the cobalt salt is 1:1 to 3.

3. The method for preparing an iron-cobalt bimetallic catalyst supported on alumina foam ceramic according to claim 1 or 2, characterized in that: The ferrous salt includes at least one of ferrous acetate, ferrous sulfate, and ferrous chloride; The cobalt salt includes at least one of cobalt nitrate, cobalt sulfate, and cobalt chloride; The mass ratio of the alumina powder to the solution containing ferrous salt, cobalt salt and complexing agent is 0.5~3:

20.

4. The method for preparing an iron-cobalt bimetallic catalyst supported on alumina foam ceramic according to claim 1, characterized in that: The molar amount of the complexing agent is 2 to 4 times the total molar amount of the ferrous salt and the cobalt salt; The complexing agent includes at least one of oxalic acid, citric acid, ethylenediaminetetraacetic acid, 2,2-bipyridine, and 1,10-phenanthroline.

5. The method for preparing an iron-cobalt bimetallic catalyst supported on alumina foam ceramic according to claim 1, characterized in that: The temperature of the loading reaction is 60~90℃.

6. The method for preparing an iron-cobalt bimetallic catalyst supported on alumina foam ceramic according to claim 1, characterized in that: The oxidation-reduction calcination includes oxidation calcination and reduction calcination. The conditions for oxidation calcination are: an oxygen-containing atmosphere, a temperature of 250~400℃, and a time of 0.5~3h. The conditions for reduction calcination are: a reducing atmosphere, a temperature of 600~900℃, and a time of 1~4h.

7. The method for preparing an iron-cobalt bimetallic catalyst supported on alumina foam ceramic according to claim 1, characterized in that: The amount of foaming agent added is 0.5~3.0 wt% of the alumina powder loaded with iron-cobalt bimetallic nanoparticles; The amount of binder added is 3.0~7.0 wt% of the alumina powder loaded with iron-cobalt bimetallic nanoparticles; The foaming agent includes at least one of ammonium carbonate, ammonium bicarbonate, and azodicarbonamide; The adhesive includes at least one of polyvinyl alcohol, polyethylene glycol, and polyvinyl butyral.

8. The method for preparing an iron-cobalt bimetallic catalyst supported on alumina foam ceramic according to claim 1 or 7, characterized in that: The sintering conditions are: a protective atmosphere, a temperature of 1200~1500℃, and a time of 2~4h.

9. A bimetallic catalyst supported on alumina foam ceramic, characterized in that: Prepared by the method described in any one of claims 1 to 8.

10. The application of the iron-cobalt bimetallic catalyst supported on alumina foam ceramic as described in claim 9, characterized in that: Used for catalytic ozone oxidation of Tl + For Tl 3+ .

Images