Preparation method and application of bimetallic loaded coal gasification ash catalyst

Abstract

The invention discloses a preparation method and application of a bimetallic loaded coal gasification ash catalyst, and the preparation method comprises the following steps: S1, grinding, screening, washing and drying ash to obtain an ash carrier; s2, adding metal salt into water, and stirring to obtain a precursor solution; s3, adding the ash carrier into the precursor solution, and stirring to obtain a mixed solution; and S4, adding hydroxide into the mixed solution, carrying out hydrothermal reaction, washing, drying, grinding and calcining to obtain the supported coal gasification ash catalyst. Cheap ash is taken as a carrier, waste resources are reasonably utilized, not only is environmental pollution reduced, but also recycling of the resources is realized, uniform distribution and firm combination of metal ions on the surface of the ash are effectively promoted by adopting a hydrothermal method, the bimetallic loaded coal gasification ash catalyst is synthesized, and the bimetallic loaded coal gasification ash catalyst can be used for treating COD (Chemical Oxygen Demand) in coal chemical industry wastewater. The method has the advantages of high removal rate, stability, application feasibility and the like, and has excellent industrial application potential.

Description

Technical Field

[0001] The invention relates to the technical field of catalysts, and in particular to a preparation method and application of a bimetallic supported coal gasification ash catalyst. Background Art

[0002] Ash and wastewater produced by coal gasification process are two harmful substances produced in the coal chemical production process. The treatment of both will not only affect the economic benefits of the enterprise, but also damage the ecological environment. At present, the treatment methods of these two harmful substances cannot achieve the purpose of both meeting economic benefits and ecological interests. Therefore, the high-value resource utilization of coal gasification ash and reducing the treatment cost of wastewater have received extensive attention from scientific researchers.

[0003] Coal gasification ash is composed of residual carbon, SiO2, Al2O3, Fe2O3 and other metal oxides. Its composition is very complex, and it is difficult to realize its resource utilization and high-value utilization. At present, the main methods of treating coal gasification ash at home and abroad are landfill, preparation of building materials and catalysts. Landfill treatment will cause environmental pollution, and the preparation of building materials cannot achieve high-value utilization of ash. The preparation of catalysts can avoid ecological problems and achieve high-value utilization. The use of coal gasification ash to prepare catalysts is mainly to use it as a carrier. Different active components also have a great influence on the performance of catalysts prepared from ash. Therefore, it is of great significance to select suitable active metals and develop ash catalysts with high activity and stability.

[0004] Coal gasification wastewater contains a variety of toxic and harmful substances, resulting in high COD in the water body. Various treatment processes cannot simultaneously meet the requirements of good COD removal effect and low investment cost. Most of the coal chemical wastewater treatment at home and abroad adopts ozone catalytic oxidation technology, and the most expensive part of the ozone catalytic oxidation process is the catalyst. At present, the ozone oxidation catalysts used in China are still mainly imported and very expensive. Therefore, the development of low-cost and high-performance ozone catalytic oxidation catalysts is the key to reducing the cost of coal chemical wastewater treatment.

[0005] In summary, preparing coal gasification ash into a low-cost ozone catalytic oxidation catalyst for removing COD in coal gasification wastewater has practical significance for coal chemical enterprises. Summary of the invention

[0006] The present invention overcomes the shortcomings of the prior art and provides a preparation method and application of a bimetallic supported coal gasification ash catalyst, which can significantly reduce the COD in coal gasification wastewater and achieve the purpose of reducing the cost of wastewater ozone catalytic oxidation treatment.

[0007] To achieve the above object, the technical solution adopted by the present invention is: a method for preparing a bimetallic supported coal gasification ash catalyst, comprising the following steps:

[0008] S1. Grinding and sieving coal gasification ash, washing and drying with water to obtain an ash carrier;

[0009] S2, adding two metal salts into water, stirring until dissolved and standing to obtain an active metal precursor solution;

[0010] S3, adding the ash carrier in S1 to the active metal precursor solution in S2, and stirring and standing to obtain a mixed solution;

[0011] S4. Adding hydroxide to the mixed solution obtained in S3, stirring, and then performing a hydrothermal reaction to obtain a solid-liquid mixture, centrifuging to obtain a solid, and washing, drying, grinding and calcining to obtain a supported coal gasification ash catalyst.

[0012] In a preferred embodiment of the present invention, in the step S1, the grinding is a mechanical ball mill or a jet mill; the screening is specifically: the ground ash is passed through 40 mesh and 70 mesh sieves respectively, and 40-70 mesh ash is taken; the washing is specifically: the sieved ash is washed with water 3-5 times; the drying is specifically: the washed ash is dried in a drying oven at a temperature of 100-120°C for 8-12h.

[0013] In a preferred embodiment of the present invention, in the step S2, the metal salt is one of cerium nitrate, manganese nitrate, iron nitrate, copper nitrate or cobalt nitrate; and the mass ratio of the two metal salts to the water is 1:4.5-6.5.

[0014] In a preferred embodiment of the present invention, in the step S3, the mass ratio of the amount of the ash added to the amount of the active metal theoretically generating a single metal oxide is 50 to 5:1.

[0015] In a preferred embodiment of the present invention, in the step S3, the stirring time is 10 to 14 hours; the static immersion time is 10 to 14 hours.

[0016] In a preferred embodiment of the present invention, in the step S4, the hydroxide is one of sodium hydroxide or potassium hydroxide; the mass ratio of the mixed solution to the hydroxide is 1:2-2.5, and the concentration of the hydroxide is 5-10 mol / L.

[0017] In a preferred embodiment of the present invention, in the step S4, the stirring time is 3 to 4.5 hours; the hydrothermal reaction is specifically: the stirred solution is transferred to a hydrothermal kettle, reacted at a temperature of 100 to 130° C. for 3 to 5 hours, and cooled to room temperature to complete the reaction.

[0018] In a preferred embodiment of the present invention, in the step S4, the washing is specifically: washing the solid with water until the washing water is neutral, and then washing with anhydrous ethanol; the drying is specifically: drying the washed solid in a drying oven at a temperature of 80 to 90° C. for 10 to 14 hours; the grinding is specifically: grinding the dried solid into a powder; and the calcining is specifically: calcining the ground powdered solid in a muffle furnace at a temperature of 580 to 610° C. for 1.5 to 3 hours.

[0019] The present invention provides an application of a bimetallic supported coal gasification ash catalyst. The bimetallic supported coal gasification ash catalyst is obtained by the aforementioned preparation method. The supported coal gasification ash catalyst and ozone are introduced into coal gasification wastewater together to catalytically oxidize and remove COD in the coal gasification wastewater.

[0020] In a preferred embodiment of the present invention, when the COD of the coal gasification wastewater is 200-300 mg / L, the amount of the supported coal gasification ash catalyst added to the ozone catalytic reactor is 1-6 g / L, and the amount of ozone added is 1-4 L / min.

[0021] The present invention solves the defects existing in the background technology and has the following beneficial effects:

[0022] (1) The present invention provides a preparation method and application of a bimetallic supported coal gasification ash catalyst. By using cheap ash as a carrier and rationally utilizing waste resources, it not only reduces environmental pollution but also realizes the recycling of resources. A hydrothermal method is used to effectively promote the uniform distribution and firm bonding of metal ions on the ash surface, and a bimetallic supported coal gasification ash catalyst is synthesized. For COD in coal chemical wastewater, it shows advantages such as high removal rate, stability and application feasibility, and has excellent industrial application potential.

[0023] (2) In the present invention, the active components of the ash catalyst loaded are cerium and manganese. Cerium can serve as an electron acceptor or donor, which can accelerate the breaking and recombination of chemical bonds in organic molecules. Manganese, as an element with catalytic activity, can form a variety of oxides or hydroxides. The compounds have a large specific surface area and abundant surface hydroxyl groups, which can adsorb and catalytically oxidize organic matter in wastewater. When the active components loaded in the present invention are cerium and manganese, the synergistic effect between cerium and manganese can cause electron transfer and redox reactions to form more superoxide radicals and hydroxyl radicals, making it have extremely strong oxidizing ability, which can accelerate the oxidative decomposition process of organic matter in wastewater, so that the chemical bonds in organic molecules are broken and recombined into harmless or low-toxic substances, thereby achieving the purification of coal chemical wastewater.

[0024] (3) In the present invention, when the active components cerium and manganese are loaded onto the coal gasification ash at an appropriate cerium-manganese ratio, the valence distribution of cerium and manganese can reach a better equilibrium point. The interaction between the two optimizes the electronic structure of the catalyst, so that the catalyst can transfer electrons more effectively in the redox reaction, thereby facilitating the adsorption and activation of ozone molecules and promoting its reaction with organic molecules, so that the catalyst exhibits excellent ozone catalytic oxidation performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 The present invention is a flow chart of a method for preparing a bimetallic supported coal gasification ash catalyst. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0029] It should be noted that the raw materials, equipment and reagents used in the present invention can be purchased from the market or obtained through the preparation methods of existing technologies.

[0030] like Figure 1 As shown, a method for preparing a bimetallic supported coal gasification ash catalyst comprises the following steps:

[0031] S1. Grinding and sieving coal gasification ash, washing and drying with water to obtain an ash carrier;

[0032] S2, adding two metal salts into water, stirring until dissolved and standing to obtain an active metal precursor solution;

[0033] S3, adding the ash carrier in S1 to the active metal precursor solution in S2, and stirring and standing to obtain a mixed solution;

[0034] S4. Adding hydroxide to the mixed solution obtained in S3, stirring, and then performing a hydrothermal reaction to obtain a solid-liquid mixture, centrifuging to obtain a solid, and washing, drying, grinding and calcining to obtain a supported coal gasification ash catalyst.

[0035] In some specific embodiments, in step S1, grinding is performed by mechanical ball milling or air flow milling; screening is performed by sieving the ground ash through 40-mesh and 70-mesh sieves, respectively, to obtain 40-70-mesh ash; washing is performed by washing the sieved ash with water for 3-5 times; drying is performed by drying the washed ash in a drying oven at a temperature of 100-120° C. for 8-12 hours.

[0036] In some specific embodiments, in step S2, the metal salt is one of cerium nitrate, manganese nitrate, iron nitrate, copper nitrate or cobalt nitrate; and the mass ratio of the two metal salts to water is 1:4.5-6.5.

[0037] In some specific embodiments, in step S3, the mass ratio of the amount of ash added to the theoretical amount of the active metal to generate a single metal oxide is 50 to 5:1; the stirring time is 10 to 14 hours; and the static immersion time is 10 to 14 hours.

[0038] In some specific embodiments, in step S4, the hydroxide is one of sodium hydroxide or potassium hydroxide; the mass ratio of the mixed solution to the hydroxide is 1:2-2.5, and the concentration of the hydroxide is 5-10 mol / L; the stirring time is 3-4.5 h; the hydrothermal reaction is specifically: the stirred solution is transferred to a hydrothermal kettle, reacted at a temperature of 100-130°C for 3-5 h, and cooled to room temperature to complete the reaction; washing is specifically: washing the solid with water until the washing water is neutral, and then washing with anhydrous ethanol; drying is specifically: drying the washed solid in a drying oven at a temperature of 80-90°C for 10-14 h; grinding is specifically: grinding the dried solid into powder; calcination is specifically: calcining the ground powdered solid in a muffle furnace at a temperature of 580-610°C for 1.5-3 h.

[0039] The present invention provides an application of a bimetallic supported coal gasification ash catalyst: the bimetallic supported coal gasification ash catalyst is obtained by the aforementioned preparation method, and the supported coal gasification ash catalyst and ozone are introduced into coal gasification wastewater together for catalytic oxidation to remove COD (chemical oxygen demand) in the coal gasification wastewater.

[0040] In some specific embodiments, when the COD of coal gasification wastewater is 200-300 mg / L, the amount of supported coal gasification ash catalyst added to the ozone catalytic reactor is 1-6 g / L, and the amount of ozone added is 1-4 L / min.

[0041] Example 1

[0042] A method for preparing a bimetallic supported coal gasification ash catalyst comprises the following steps:

[0043] S1, coal gasification ash mechanically ground, passed through 40 mesh and 70 mesh sieves, took 40-70 mesh ash, washed with water three times, dried in a drying oven at 105 ° C for 12h, and obtained SL (ash carrier);

[0044] S2, weigh 5.0462g of Ce(NO3)3·6H2O and 8.2276g of 50wt% Mn(NO3)2 aqueous solution, add them into 69mL of water, stir until completely dissolved, and obtain an active metal precursor solution;

[0045] S3, weigh 20g SL, add it to the active metal precursor solution, and continue stirring for 12h, let it stand and soak for 12h to obtain a mixed solution;

[0046] S4. Add 240 mL of 8 mol / L sodium hydroxide solution to the mixed solution, continue stirring for 4 hours, transfer to a hydrothermal kettle, react at 120° C. for 4 hours, cool the hydrothermal kettle to room temperature, take out the solid-liquid mixture, and centrifuge to obtain a solid. Wash the solid with water until the washing water is neutral, and then wash with anhydrous ethanol. Place the washed solid in a drying oven and dry it at 85° C. for 12 hours. Grind the dried solid into powder, and calcine it in a muffle furnace at 600° C. for 2 hours to obtain a Ce-Mn / SL bimetallic supported coal gasification ash catalyst.

[0047] Example 2

[0048] This embodiment is basically the same as embodiment 1, except that: Mn(NO3)2 in step S2 is replaced by ferric nitrate in an amount of 10.1196 g to obtain a Ce-Fe / SL bimetallic loaded coal gasification ash catalyst.

[0049] Example 3

[0050] This embodiment is basically the same as the embodiment 1, except that the Ce(NO3)3·6H2O in step S2 is replaced by ferric nitrate in an amount of 10.1196 g to obtain a Fe-Mn / SL bimetallic supported coal gasification ash catalyst.

[0051] Example 4

[0052] This embodiment is basically the same as embodiment 1, except that the Ce(NO3)3·6H2O in step S2 is replaced by cobalt nitrate in an amount of 7.0185 g to obtain a Co-Mn / SL bimetallic supported coal gasification ash catalyst.

[0053] Example 5

[0054] This embodiment is basically the same as embodiment 1, except that: Mn(NO3)2 in step S2 is replaced by cobalt nitrate in an amount of 7.0185 g to obtain a Ce-Co / SL bimetallic loaded coal gasification ash catalyst.

[0055] Example 6

[0056] This embodiment is basically the same as embodiment 1, except that: Mn(NO3)2 in step S2 is replaced by copper nitrate in an amount of 6.0745 g to obtain a Ce-Cu / SL bimetallic loaded coal gasification ash catalyst.

[0057] Example 7

[0058] This embodiment is basically the same as the embodiment 1, except that the Ce(NO3)3·6H2O in step S2 is replaced by copper nitrate to obtain a Cu-Mn / SL bimetallic supported coal gasification ash catalyst.

[0059] Control group 1

[0060] A foreign commercial catalyst is commercially available.

[0061] Furthermore, the ozone catalytic oxidation evaluation device is mainly composed of an ozone generator and an ozone catalytic oxidation reactor. The ozone generator provides high-purity oxygen through an oxygen cylinder, and the ozone is taken out from the ozone generator and introduced into the ozone catalytic oxidation reactor, with an ozone flow meter connected in the middle. The ozone catalytic oxidation reactor gas outlet is connected to an ozone treatment device.

[0062] The experimental procedures of ozone catalytic oxidation are divided into three steps.

[0063] 1. Take 2.0 g of the bimetallic supported coal gasification ash catalyst prepared in Example 1-7, load it into an ozone catalytic oxidation reactor, and add 1000 mL of coal chemical wastewater;

[0064] 2. Turn on the oxygen, and wait for the gas flow to stabilize for about 3 minutes, then turn on the ozone generator;

[0065] 3. Turn on the flow meter and set the ozone flow rate to 2L / min. At this time, start timing, take samples at the predetermined time, and measure the COD value; the longest reaction time is 2h.

[0066] The COD of the wastewater was measured, and after 2 hours of ozone catalytic oxidation reaction, the COD of the wastewater was measured again, and the COD removal rate of the bimetallic supported coal gasification ash catalyst of Examples 1-7 was calculated. The results are shown in Table 1.

[0067]

[0068]

[0069] It can be seen from Table 1 that:

[0070] By comparing the COD removal rates (%) of the catalysts prepared in Examples 1-7, it can be learned that the ash catalyst loaded with active components of cerium and manganese in the present invention has a COD removal rate of 81.7% for wastewater, and the COD removal rates of other bimetallic loaded coal gasification ash catalysts for wastewater are all between 55.0% and 73.3%. Since cerium can be used as an electron acceptor or donor, it can accelerate the breaking and recombination of chemical bonds in organic molecules, and manganese, as an element with catalytic activity, can form a variety of oxides or hydroxides, and the compound has a large specific surface area and abundant surface hydroxyl groups, which can adsorb and catalytically oxidize organic matter in wastewater. When the active components loaded in the present invention are cerium and manganese, the synergistic effect between cerium and manganese can cause electron transfer and redox reaction, forming more superoxide radicals and hydroxyl radicals, so that it has extremely strong oxidizing ability, can accelerate the oxidation and decomposition process of organic matter in wastewater, and break the chemical bonds in organic molecules and recombine them into harmless or low-toxic substances, thereby achieving wastewater purification. It can be seen that the effect of cerium and manganese bimetallic supported coal gasification ash catalyst on ozone catalytic oxidation is better than other bimetallic supported catalysts. In addition, compared with a foreign commercial catalyst, Ce-Mn / SL also showed a higher COD removal rate.

[0071] In order to further make the purpose and effect of the present invention simple and easy to understand, the present invention is further described in combination with specific comparative examples and catalyst evaluation results.

[0072] Comparative Example 1

[0073] This comparative example is basically the same as Example 1, except that: in step S2, the amount of Ce(NO3)3·6H2O used is 8.0737 g, and the amount of Mn(NO3)2 used is 3.2892 g; a Ce-Mn / SL bimetallic loaded coal gasification ash catalyst with a Ce to Mn ratio of 4:1 is obtained.

[0074] Comparative Example 2

[0075] This comparative example is basically the same as Example 1, except that: in step S2, the amount of Ce(NO3)3·6H2O used is 6.7264 g, and the amount of Mn(NO3)2 used is 5.4916 g; a Ce-Mn / SL bimetallic loaded coal gasification ash catalyst with a Ce to Mn ratio of 2:1 is obtained.

[0076] Comparative Example 3

[0077] This comparative example is basically the same as Example 1, except that: in step S2, the amount of Ce(NO3)3·6H2O used is 3.3657 g, and the amount of Mn(NO3)2 used is 10.9748 g; a Ce-Mn / SL bimetallic loaded coal gasification ash catalyst with a Ce to Mn ratio of 1:2 is obtained.

[0078] Comparative Example 4

[0079] This comparative example is basically the same as Example 1, except that: in step S2, the amount of Ce(NO3)3·6H2O used is 2.0184 g, and the amount of Mn(NO3)2 used is 13.1730 g; a Ce-Mn / SL bimetallic loaded coal gasification ash catalyst with a Ce to Mn ratio of 1:4 is obtained.

[0080] The bimetallic supported coal gasification ash catalyst prepared in Comparative Examples 1-4 was used to evaluate the removal of COD in coal chemical wastewater. The results are shown in Table 2.

[0081]

[0082] It can be seen from Table 2 that:

[0083] By comparing the COD removal rates (%) of the catalysts prepared in Example 1 with those in Comparative Examples 1-4, it can be seen that the COD removal rates of the Ce-Mn / SL catalysts prepared in the comparative examples with cerium-manganese ratios of 4:1, 2:1, 1:2 and 1:4 for coal chemical wastewater are 77.6%, 62.8%, 69.5% and 65.4%, respectively. When the cerium-manganese ratio is 1:1 and loaded onto the coal gasification ash, the valence distribution of cerium and manganese can reach a better balance point, and the interaction between the two optimizes the electronic structure of the catalyst, so that the catalyst can transfer electrons more effectively in the redox reaction, thereby facilitating the adsorption and activation of ozone molecules and promoting its reaction with organic molecules, so that the catalyst exhibits excellent ozone catalytic oxidation performance.

[0084] The above is based on the ideal embodiment of the present invention. Through the above description, it is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is limited by the attached claims rather than the above description, and it is intended to include all changes within the meaning and scope of the equivalent elements of the claims. Any figure mark in the claims should not be regarded as limiting the claims involved.

[0085] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for preparing a bimetallic supported coal gasification ash catalyst, characterized in that: The following steps are involved: S1. Grinding and sieving coal gasification ash, washing and drying with water to obtain an ash carrier; S2, adding two metal salts into water, stirring until dissolved and standing to obtain an active metal precursor solution; S3, adding the ash carrier in S1 to the active metal precursor solution in S2, and stirring and standing to obtain a mixed solution; S4. Adding hydroxide to the mixed solution obtained in S3, stirring, and then performing a hydrothermal reaction to obtain a solid-liquid mixture, centrifuging to obtain a solid, and washing, drying, grinding and calcining to obtain a supported coal gasification ash catalyst.

2. The method for preparing a bimetallic supported coal gasification ash catalyst according to claim 1, characterized in that: In the step S1, the grinding is one of mechanical ball milling and air flow milling; the screening is specifically: the ground ash is passed through 40 mesh and 70 mesh sieves respectively, and 40-70 mesh ash is taken; the washing is specifically: the sieved ash is washed with water for 3-5 times; the drying is specifically: the washed ash is dried in a drying oven at a temperature of 100-120° C. for 8-12 hours.

3. The method for preparing a bimetallic supported coal gasification ash catalyst according to claim 1, characterized in that: In the step S2, the metal salt is one of cerium nitrate, manganese nitrate, iron nitrate, copper nitrate or cobalt nitrate; and the mass ratio of the two metal salts to the water is 1:4.5-6.

5.

4. The method for preparing a bimetallic supported coal gasification ash catalyst according to claim 1, characterized in that: In the step S3, the mass ratio of the added amount of the ash to the theoretical amount of the active metal to generate a single metal oxide is 50 to 5:

1.

5. The method for preparing a bimetallic supported coal gasification ash catalyst according to claim 1, characterized in that: In the step S3, the stirring time is 10 to 14 hours; the static immersion time is 10 to 14 hours.

6. The method for preparing a bimetallic supported coal gasification ash catalyst according to claim 1, characterized in that: In the step S4, the hydroxide is one of sodium hydroxide and potassium hydroxide; the mass ratio of the mixed solution to the hydroxide is 1:2-2.5, and the concentration of the hydroxide is 5-10 mol / L.

7. The method for preparing a bimetallic supported coal gasification ash catalyst according to claim 1, characterized in that: In the step S4, the stirring time is 3 to 4.5 hours; the hydrothermal reaction is specifically: transferring the stirred solution to a hydrothermal kettle, reacting at a temperature of 100 to 130° C. for 3 to 5 hours, and cooling to room temperature to complete the reaction.

8. The method for preparing a bimetallic supported coal gasification ash catalyst according to claim 1, characterized in that: In the step S4, the washing is specifically: washing the solid with water until the washing water is neutral, and then washing with anhydrous ethanol; the drying is specifically: drying the washed solid in a drying oven at a temperature of 80 to 90° C. for 10 to 14 hours; the grinding is specifically: grinding the dried solid into powder; and the calcining is specifically: calcining the ground powdered solid in a muffle furnace at a temperature of 580 to 610° C. for 1.5 to 3 hours.

9. An application of a bimetallic supported coal gasification ash catalyst, characterized in that: The bimetallic supported coal gasification ash catalyst is obtained by the preparation method as described in any one of claims 1 to 8, and the supported coal gasification ash catalyst and ozone are introduced into coal gasification wastewater together to catalytically oxidize and remove COD in the coal gasification wastewater.

10. The use of a bimetallic supported coal gasification ash catalyst according to claim 9, characterized in that: When the COD of the coal gasification wastewater is 200-300 mg / L, the amount of the supported coal gasification ash catalyst added to the ozone catalytic reactor is 1-6 g / L, and the amount of ozone added is 1-4 L / min.

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