Method for synthesizing calcium sulfate nanorod by regulating and controlling morphology of waste gypsum, calcium sulfate nanorod and application thereof, supported aromatic nitro hydrogenation catalyst and preparation method of supported aromatic nitro hydrogenation catalyst
By synthesizing calcium sulfate nanorods through morphological regulation of waste gypsum, and using them as a carrier to prepare a supported aromatic nitro hydrogenation catalyst, the problems of environmental pollution and high energy consumption in the resource utilization of waste gypsum have been solved, and efficient and low-cost industrial production has been achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CENT SOUTH UNIV
- Filing Date
- 2026-01-30
- Publication Date
- 2026-05-12
AI Technical Summary
In existing technologies, the resource utilization of waste gypsum faces problems such as complex processes, environmental pollution, high energy consumption, high costs, and low product purity, and traditional methods are difficult to promote and apply on a large scale.
By using inducing and modifying reagents to control the morphology of waste gypsum, calcium sulfate nanorods were synthesized and used as supports to prepare supported aromatic nitro hydrogenation catalysts. The catalysts were prepared by volume impregnation and reduction calcination, which simplified the process and reduced energy consumption and cost.
This method achieves efficient synthesis of calcium sulfate nanorods and high activity of supported catalysts, solving the environmental pollution and energy consumption problems of traditional methods. The preparation process is simple and suitable for industrial production.
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Figure CN122010160A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a method for synthesizing calcium sulfate nanorods by morphological control of waste gypsum, the calcium sulfate nanorods and their applications, a supported aromatic nitro hydrogenation catalyst and its preparation method, belonging to the fields of high-value-added resource utilization technology of solid waste and multiphase hydrogenation catalysis. Background Technology
[0002] Industrial waste gypsum refers to gypsum-like substances produced as byproducts or waste during industrial production processes, with calcium sulfate dihydrate or calcium sulfate hemihydrate as their main chemical components. If massive amounts of industrial waste gypsum are not effectively treated and utilized, and are merely stored in the open, it will cause serious environmental hazards and social problems.
[0003] The existing methods for utilizing waste gypsum are as follows: (1) Preparation of calcium sulfate powder. Chinese patent (CN113603128A) discloses a method for preparing various calcium sulfate powders from industrial by-product gypsum. The process involves dissolving industrial by-product gypsum in an acid solution to obtain a crude calcium sulfate acidic solution, filtering to obtain a refined calcium sulfate acidic solution; adding concentrated sulfuric acid or a solution of concentrated sulfuric acid and ethanol to obtain a calcium sulfate suspension in dihydrate or a calcium sulfate suspension in hemihydrate, filtering, and adjusting the pH to obtain the product. However, this method is relatively complex and requires the use of strong acid, which may release toxic and harmful gases during the reaction process, endangering the environment, and requiring high corrosion resistance of the reaction vessel. (2) Growth of calcium sulfate whiskers from fluorogypsum slag. Chinese patent (CN110528060A) discloses a method for growing calcium sulfate whiskers from fluorogypsum slag. The process involves using fluorogypsum slag as raw material, grinding it, and mixing it with water to obtain a slurry. Soluble carbonate is added to the slurry, and after stirring and reacting, the mixture is filtered to obtain a first filtrate and a first filter residue. Acid solution was added to the first filter residue, and after stirring and reaction, the second filtrate and the second filter residue were obtained by filtration. The first filtrate and the second filtrate were mixed to obtain a calcium sulfate colloidal solution. A crystal growth promoter was added to the calcium sulfate colloidal solution, and after hydrothermal reaction, the reaction was allowed to stand and then dried to obtain calcium sulfate whiskers. However, this method is relatively complicated; and it uses acid and carbonate, which will release a large amount of greenhouse gases; the reaction consumes a lot of energy, which is not conducive to large-scale promotion and application. (3) Calcination to produce gypsum powder. Chinese patent (publication number CN101033118A) discloses a new calcination process for gypsum. This process is designed for the characteristics of industrial by-product gypsum (complex composition, fine particles, and high content of attached water). It adopts a unique calcination process method, namely, a combination of countercurrent and cocurrent flow, and a vortex tube that can be introduced into the kiln to achieve a new process of mixed calcination of external calcination (indirect calcination) and internal calcination (direct calcination). However, due to the volatilization of phosphoric acid and fluoride during calcination, the environment will be polluted and the equipment will be corroded. The energy consumption cost of high-temperature calcination is large, and its application will be greatly limited. Meanwhile, since the most abundant impurity in phosphogypsum is quartz, the calcination process cannot remove these quartz impurities, so this method cannot produce high-whiteness, high-purity, high-quality gypsum products. (4) Preparation of non-fired bricks. The literature (Jun Zhou, Hui Gao, Zhu Shu, Yanxin Wang, Chunjie Yan. Utilization of waste phosphogypsum to prepare non-fired bricks by a novel Hydration–Recrystallization process[J]. Construction and Building Materials, 2012, 34: 114-119.) proposes a new process called "hydration-recrystallization process" to prepare non-fired bricks using waste phosphogypsum.In this process, the pressed raw bricks are heat-dried at 180°C to dehydrate the gypsum into hemihydrated gypsum, then soaked in water to recrystallize the gypsum in situ, and finally air-dried to obtain unfired brick products. This process has the problem of high energy consumption and low natural air-drying efficiency, making it difficult to promote and apply on a large scale. (5) Chinese Patent (Publication No. CN118359221A) discloses a method for preparing phosphogypsum-based high-strength gypsum from atmospheric pressure salt solution: nitrate, crystallizing agent and deionized water are poured into a container in sequence and stirred until completely dissolved to obtain a salt solution system; the salt solution system is heated to the hydrothermal reaction temperature, and then phosphogypsum is added for hydrothermal reaction; after the hydrothermal reaction is completed, the hydrothermal reaction system is immediately filtered; the filter cake after filtration of the mixture is washed and dried; the filtrate after filtration is collected and recycled. However, a high concentration of Cl is usually introduced into the atmospheric pressure salt solution system. - Ions can accelerate the corrosion of the inner walls of metal reactors and metal structures in buildings during actual production and applications.
[0004] In addition to the methods mentioned above, calcium sulfate in waste gypsum can also be used to prepare catalysts for thermocatalytic reactions: The literature (Yu Ping. Study on the synthesis of butyl acetate by calcium sulfate whiskers based on orthogonal experiment [J]. Guangdong Chemical Industry, 2019, 46(19): 94-95.) reported that modified calcium sulfate whiskers can be used as a catalyst for transesterification to synthesize butyl acetate, and a yield of 70% can be achieved by reacting at 110℃ for 6 hours. (2) The literature (Zhang Lianhong, Tian Yanwen. Synthesis of trimethylolpropane triacrylate catalyzed by calcium sulfate whiskers [J]. Journal of Molecular Science, 2009, 25(06):375-378.DOI:10.13563 / j.cnki.jmolsci.2009.06.006.) reported the study of the synthesis of trimethylolpropane triacrylate (TMPTA) using trimethylolpropane (TMP) and acrylic acid (AA) as raw materials, calcium sulfate whiskers as catalyst, and a mixture of cyclohexane and toluene as dehydrating agent. The esterification rate of the trimethylolpropane triacrylate synthesized at 98℃ for 5h was greater than 96.8%, and the purity reached 97.6%. (3) The literature (Zhang Lianhong, Tian Yanwen. Synthesis of diethylene glycol dimethacrylate catalyzed by calcium sulfate whiskers [J]. Materials Reports, 2009, 23(10):35-37.) reported on the catalytic effect of calcium sulfate whiskers on the synthesis of diethylene glycol dimethacrylate. Under the optimal reaction conditions, the yield of diethylene glycol dimethacrylate synthesized was greater than 96.3%, and the purity reached 97%. Summary of the Invention
[0005] To address the problems existing in the prior art, one of the objectives of this invention is to provide a method for synthesizing calcium sulfate nanorods from waste gypsum through morphological control. This method utilizes inducing and modifying reagents to synthesize active materials from waste gypsum, innovatively utilizing the calcium sulfate in the waste gypsum to create high-value-added calcium sulfate nanorods. This solves the problems of cost and environmental pollution associated with traditional resource utilization of waste gypsum.
[0006] The second objective of this invention is to provide a calcium sulfate nanorod.
[0007] The third objective of this invention is to provide an application of calcium sulfate nanorods as a support for the preparation of supported aromatic nitro hydrogenation catalysts.
[0008] The fourth objective of this invention is to provide a supported aromatic nitro hydrogenation catalyst that exhibits high activity and high selectivity for the preparation of amine compounds by aromatic nitro hydrogenation.
[0009] The fifth objective of this invention is to provide a method for preparing a supported aromatic nitro hydrogenation catalyst. This method can prepare the hydrogenation catalyst by volume impregnation and reduction calcination. The preparation method is simple and easy to industrialize.
[0010] To achieve the above objectives, a first aspect of the present invention provides a method for synthesizing calcium sulfate nanorods by morphological control of waste gypsum, the method comprising:
[0011] Waste gypsum was mixed with a solution containing inducing and modifying reagents and stirred to react. The solid was then washed and dried to obtain calcium sulfate nanorods.
[0012] The inducing agent is a soluble sulfate and / or a soluble persulfate; the modifying agent is selected from at least one of surfactants, sodium salts of organic acids, potassium salts of organic acids, alkali metal chlorides, alkaline earth metal chlorides, and soluble polymers.
[0013] The surfactant is selected from at least one of Tween-20, Tween-40, Tween-60, and Tween-80;
[0014] The organic acid sodium salt is selected from at least one of disodium ethylenediaminetetraacetate, sodium malate, sodium tartrate, and sodium oxalate;
[0015] The organic acid potassium salt is selected from at least one of potassium malate, potassium tartrate and potassium oxalate;
[0016] The alkali metal chloride is potassium chloride and / or sodium chloride;
[0017] The alkaline earth metal chloride is selected from at least one of magnesium chloride, calcium chloride and barium chloride;
[0018] The soluble polymer is polyethylene glycol and / or polyacrylic acid.
[0019] The innovation of this invention lies in the synthesis of waste gypsum-based active calcium sulfate nanorods from waste gypsum using inducing and modifying reagents. It innovatively utilizes the calcium sulfate in waste gypsum, enabling the synthesis of high-value-added active material short rod-shaped calcium sulfate nanorods through morphology control. By using modifying reagents to control the growth rate of different calcium sulfate crystal faces, precise control of crystal morphology is achieved. This not only solves the problems of cost and environmental pollution associated with traditional waste gypsum resource utilization, but also endows the prepared calcium sulfate nanorods with different morphologies with excellent activity.
[0020] Furthermore, this invention can prepare active calcium sulfate nanorods under normal pressure without the need for pressurization, and it does not generate secondary pollution such as carbon oxides and nitrogen oxides. The reaction conditions are relatively mild, the energy required is low, and most of the modifying reagents used as solvents after the reaction can be recovered by certain means. It has the advantages of low cost, low energy consumption, and green environmental protection.
[0021] As a preferred embodiment, the soluble sulfate is selected from at least one of sodium sulfate, potassium sulfate, sodium bisulfate, potassium bisulfate, and magnesium sulfate;
[0022] The soluble persulfate is sodium persulfate and / or potassium persulfate.
[0023] As a preferred embodiment, the waste gypsum is selected from at least one of phosphogypsum, salt gypsum, desulfurized gypsum, fluorogypsum, titanium gypsum, and citric acid gypsum.
[0024] As a preferred embodiment, in the solution containing the inducing agent and the modifying agent, the mass concentration of the inducing agent is 1~50wt%, and the concentration of the modifying agent is 0.01~0.4mol / L.
[0025] As a more preferred embodiment, the mass concentration of the inducing agent in the solution containing the inducing agent and the modifying agent is 5-25 wt%. The inventors have found that the hydrogenation catalyst prepared using calcium sulfate nanorods prepared under these preferred conditions as a support exhibits superior activity.
[0026] As a preferred embodiment, the waste gypsum has a mass concentration of 1-50 wt% in the solution containing the inducing agent and the modifying agent.
[0027] As a more preferred embodiment, the waste gypsum has a mass concentration of 5-40 wt% in a solution containing an inducing agent and a modifying agent.
[0028] As a preferred embodiment, the temperature of the stirring reaction is 1~120℃, the time is 1~96h, and the stirring rate is 1~1000r / min.
[0029] As a more preferred embodiment, the temperature of the stirring reaction is 80~120℃, the time is 2~48h, and the stirring rate is 100~800r / min.
[0030] As a preferred embodiment, the drying process is carried out at a temperature of 1~100℃ for a time of 1~48h, and the drying method is vacuum drying and / or freeze drying.
[0031] As a more preferred embodiment, the drying process is carried out at a temperature of 30~70°C for a time of 10~48 hours.
[0032] As a preferred embodiment, the washing agent used is water and / or ethanol.
[0033] The second aspect of the present invention provides calcium sulfate nanorods prepared by the control method described in the first aspect.
[0034] The third aspect of the present invention provides the application of the calcium sulfate nanorods described in the second aspect above as a support for the preparation of supported aromatic nitro hydrogenation catalysts.
[0035] A fourth aspect of the present invention provides a supported aromatic nitro hydrogenation catalyst, wherein the catalyst is supported on calcium sulfate nanorods, the active component is ruthenium, and the loading of the active component is 0.1~2.5 wt%.
[0036] The calcium sulfate nanorods are the calcium sulfate nanorods described in the second aspect above.
[0037] The supported aromatic nitro hydrogenation catalyst prepared by using the calcium sulfate nanorods obtained in this invention as a support exhibits high activity and high selectivity for the preparation of amine compounds by aromatic nitro hydrogenation.
[0038] The fifth aspect of the present invention provides a method for preparing a supported aromatic nitro hydrogenation catalyst, the method comprising: stirring and mixing calcium sulfate nanorods with a ruthenium-containing solution, and then reducing and calcining them to obtain a supported aromatic nitro hydrogenation catalyst.
[0039] As a preferred embodiment, the stirring and mixing temperature is 90~120℃ and the time is 20~36h; the reduction and calcination temperature is 250~750℃ and the time is 1~4h.
[0040] As a preferred embodiment, the reducing gas in the reduction calcination contains 5-15% by volume hydrogen and 85-95% by volume inert gas, and the flow rate of the reducing gas is 10-100 mL / min.
[0041] As a preferred embodiment, the heating rate of the reduction calcination is 1~8℃ / min. It should be noted that the calcination reduction time does not include the heating time.
[0042] As a preferred embodiment, the stirring and mixing is carried out under ultrasonic conditions.
[0043] As a preferred embodiment, the ruthenium-containing solution is an aqueous solution of ruthenium chloride, and the concentration of ruthenium in the aqueous solution of ruthenium chloride is 0.1~2.5wt%.
[0044] In this invention, "normal pressure" refers to standard atmospheric pressure.
[0045] Compared with the prior art, the present invention has at least the following advantages:
[0046] (1) This invention controls the growth rate of different calcium sulfate crystal faces by modifying reagents and utilizes their selective adsorption on different calcium sulfate crystal faces to effectively change the growth rate of the crystal faces, thereby achieving precise control of crystal morphology and obtaining a novel active gypsum. The method of this invention has the advantages of simple process, mild reaction conditions, and low cost.
[0047] (2) The active calcium sulfate nanorods prepared by the method of the present invention are used as a support to prepare a supported aromatic nitro hydrogenation catalyst. The catalyst has high activity and high selectivity for the preparation of amine compounds by aromatic nitro hydrogenation. Attached Figure Description
[0048] Figure 1 This is a scanning electron microscope image of the calcium sulfate nanorods prepared in Example 1. Detailed Implementation
[0049] The endpoints and any values of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of the various ranges, the endpoint values of the various ranges and individual point values, and individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.
[0050] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments. Obviously, the embodiments described below are only a part of the embodiments, and all other embodiments obtained by those skilled in the art without creative effort are still within the scope of protection of the present invention.
[0051] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.
[0052] Example 1
[0053] The solution contains an inducing agent and a modifying agent: the inducing agent sodium sulfate has a mass concentration of 12 wt%, and the modifying agent sodium malate has a mass concentration of 0.01 mol / L.
[0054] Waste gypsum was mixed with a solution containing inducing and modifying reagents and reacted at 95°C, atmospheric pressure, and a stirring rate of 100 r / min for 4 h. After the conversion was complete, the slurry was separated into solid and liquid components. The solid was washed alternately with water and anhydrous ethanol and then vacuum dried at 45°C for 12 h to obtain calcium sulfate nanorods.
[0055] The mass concentration of waste gypsum in the solution containing inducing and modifying reagents is 10 wt%.
[0056] Example 2
[0057] The solution contains an inducing agent and a modifying agent: the inducing agent, sodium persulfate, has a mass concentration of 15 wt%, and the modifying agent, polyacrylic acid, has a mass concentration of 0.04 mol / L.
[0058] Waste gypsum was mixed with a solution containing inducing and modifying reagents and reacted at 90°C, atmospheric pressure, and a stirring rate of 100 r / min for 3 h. After the conversion was complete, the slurry was separated into solid and liquid components. The solid was washed alternately with water and anhydrous ethanol and then vacuum dried at 45°C for 12 h to obtain calcium sulfate nanorods.
[0059] The mass concentration of waste gypsum in the solution containing inducing and modifying reagents is 8 wt%.
[0060] Example 3
[0061] The solution contains an inducing agent and a modifying agent: the inducing agent, potassium sulfate, has a mass concentration of 5 wt%, and the modifying agent, disodium ethylenediaminetetraacetate, has a mass concentration of 0.08 mol / L.
[0062] Waste gypsum was mixed with a solution containing inducing and modifying reagents and reacted at 103°C, atmospheric pressure, and a stirring rate of 300 r / min for 12 h. After the conversion was complete, the slurry was separated into solid and liquid components. The solid was washed alternately with water and anhydrous ethanol and then vacuum dried at 65°C for 10 h to obtain calcium sulfate nanorods.
[0063] The mass concentration of waste gypsum in the solution containing inducing and modifying reagents is 25 wt%.
[0064] Example 4
[0065] The solution contains an inducing agent and a modifying agent: the inducing agent, sodium bisulfate, has a mass concentration of 20 wt%, and the modifying agent, polyacrylic acid, has a mass concentration of 0.32 mol / L.
[0066] Waste gypsum was mixed with a solution containing inducing and modifying reagents and reacted at 100°C, atmospheric pressure, and a stirring rate of 400 r / min for 24 h. After the conversion was complete, the slurry was separated into solid and liquid components. The solid was washed alternately with water and anhydrous ethanol and then vacuum dried at 70°C for 12 h to obtain calcium sulfate nanorods.
[0067] The mass concentration of waste gypsum in the solution containing inducing and modifying reagents is 38 wt%.
[0068] Example 5
[0069] The solution contains an inducing agent and a modifying agent: the inducing agent, potassium hydrogen sulfate, has a mass concentration of 8 wt%, and the modifying agent, disodium ethylenediaminetetraacetate, has a mass concentration of 0.02 mol / L.
[0070] Waste gypsum was mixed with a solution containing inducing and modifying reagents and reacted at 97°C, atmospheric pressure, and a stirring rate of 350 r / min for 48 h. After the conversion was complete, the slurry was separated into solid and liquid components. The solid was washed alternately with water and anhydrous ethanol and then vacuum dried at 45°C for 24 h to obtain calcium sulfate nanorods.
[0071] The mass concentration of waste gypsum in the solution containing inducing and modifying reagents is 38 wt%.
[0072] Example 6
[0073] The solution contains an inducing agent and a modifying agent: the inducing agent sodium sulfate has a mass concentration of 17 wt%, and the modifying agent Tween-80 has a mass concentration of 0.04 mol / L.
[0074] Waste gypsum was mixed with a solution containing inducing and modifying reagents and reacted at 85°C, atmospheric pressure, and a stirring rate of 600 r / min for 48 h. After the conversion was complete, the slurry was separated into solid and liquid components. The solid was washed alternately with water and anhydrous ethanol and then vacuum dried at 35°C for 48 h to obtain calcium sulfate nanorods.
[0075] The mass concentration of waste gypsum in the solution containing inducing and modifying reagents is 15 wt%.
[0076] Application examples
[0077] 0.5 g of the calcium sulfate nanorods prepared in the above example were added to ruthenium chloride aqueous solutions of different concentrations and stirred under ultrasonic conditions (temperature 100℃, time 30 h). The mixture was then transferred to a forced-air drying oven for drying. The dried samples were then subjected to calcination reduction in the presence of a reducing gas (containing 10% hydrogen and 90% nitrogen by volume, with a flow rate of 50 mL / min) to obtain a supported aromatic nitro hydrogenation catalyst. Other unlisted specific process parameters and raw material amounts are shown in Table 1.
[0078]
[0079] Test case
[0080] The supported aromatic nitro hydrogenation catalyst prepared in the application example was evaluated for its catalytic performance in a 50 ml batch hydrogenation reactor.
[0081] In the presence of hydrogen, the catalyst (20 mg) prepared in the above application example was used to hydrogenate and reduce aromatic nitro compounds at different feed mass ratios. The specific experimental conditions and results are shown in Table 2.
[0082] Gas chromatography / liquid chromatography was used to evaluate reaction conversion and selectivity.
[0083]
[0084] Note: The feed ratio is the mass ratio of the catalyst to the aromatic nitro compound.
[0085] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.
Claims
1. A method for synthesizing calcium sulfate nanorods by morphological control of waste gypsum, characterized in that: The method includes: Waste gypsum was mixed with a solution containing inducing and modifying reagents and stirred to react. The solid was then washed and dried to obtain calcium sulfate nanorods. The inducing agent is a soluble sulfate and / or a soluble persulfate; the modifying agent is selected from at least one of surfactants, sodium salts of organic acids, potassium salts of organic acids, alkali metal chlorides, alkaline earth metal chlorides, and soluble polymers. The surfactant is selected from at least one of Tween-20, Tween-40, Tween-60, and Tween-80; The organic acid sodium salt is selected from at least one of disodium ethylenediaminetetraacetate, sodium malate, sodium tartrate, and sodium oxalate; The organic acid potassium salt is selected from at least one of potassium malate, potassium tartrate and potassium oxalate; The alkali metal chloride is potassium chloride and / or sodium chloride; The alkaline earth metal chloride is selected from at least one of magnesium chloride, calcium chloride and barium chloride; The soluble polymer is polyethylene glycol and / or polyacrylic acid.
2. The method for synthesizing calcium sulfate nanorods by morphological control of waste gypsum according to claim 1, characterized in that: The soluble sulfate is selected from at least one of sodium sulfate, potassium sulfate, sodium bisulfate, potassium bisulfate, and magnesium sulfate; The soluble persulfate is sodium persulfate and / or potassium persulfate.
3. A method for synthesizing calcium sulfate nanorods by morphological control of waste gypsum according to claim 1 or 2, characterized in that: In the solution containing the inducing agent and the modifying agent, the mass concentration of the inducing agent is 1~50wt%, and the concentration of the modifying agent is 0.01~0.4mol / L; And / or, the mass concentration of the waste gypsum in the solution containing the inducing agent and the modifying agent is 1~50wt%.
4. A method for synthesizing calcium sulfate nanorods by morphological control of waste gypsum according to claim 1 or 2, characterized in that: The temperature of the stirring reaction is 1~120℃, the time is 1~96h, and the stirring rate is 1~1000r / min; And / or, the drying process is carried out at a temperature of 1~100℃ for a time of 1~48h, and the drying method is vacuum drying and / or freeze drying.
5. A method for synthesizing calcium sulfate nanorods by morphological control of waste gypsum according to claim 1 or 2, characterized in that: The washing agent used is water and / or ethanol.
6. Calcium sulfate nanorods prepared by the control method according to any one of claims 1 to 5.
7. The application of the calcium sulfate nanorods according to claim 6 as a support for the preparation of supported aromatic nitro hydrogenation catalysts.
8. A supported aromatic nitro hydrogenation catalyst, characterized in that: The hydrogenation catalyst is supported on calcium sulfate nanorods, and the active component is ruthenium, with a loading of 0.1~2.5 wt%. The calcium sulfate nanorods are those described in claim 6.
9. A method for preparing the supported aromatic nitro hydrogenation catalyst according to claim 8, characterized in that: The method includes: stirring and mixing calcium sulfate nanorods with a ruthenium-containing solution, followed by reduction and calcination to obtain a supported aromatic nitro hydrogenation catalyst.
10. The method for preparing the supported aromatic nitro hydrogenation catalyst according to claim 9, characterized in that: The stirring and mixing temperature is 90~120℃, and the time is 20~36h; the reduction and calcination temperature is 250~750℃, and the time is 1~4h. And / or, the reducing gas in the reduction calcination contains 5-15% by volume hydrogen and 85-95% by volume inert gas, and the flow rate of the reducing gas is 10-100 mL / min.