Application of supported catalyst in catalysis of catalytic oxidation reaction of ammonia gas and ozone and method for catalytic purification of ammonia gas

Abstract

The invention belongs to the technical field of air purification, and particularly relates to application of a supported catalyst in catalysis of a catalytic oxidation reaction of ammonia gas and ozone and a method for catalytic purification of ammonia gas. In the application provided by the invention, the supported catalyst comprises a metal oxide carrier and an active component supported on the metal oxide carrier, and the active component is metal silver; the temperature of the catalytic oxidation reaction is not more than 40 DEG C. The metal silver is used as an active component of the catalyst, and the ozone is used as an oxidant, so that the activation temperature of the catalyst can be effectively reduced, the catalytic oxidation reaction of ammonia gas and ozone can be realized at the temperature of less than or equal to 40 DEG C, and the purification of ammonia gas and ozone can be realized at the same time. Results of the embodiment show that the ammonia gas can be purified by 100%, the N2 selectivity is 90% or above, and therefore the method can be widely applied to catalytic purification of the ammonia gas indoors and in the livestock and poultry breeding industry.

Description

Technical Field

[0001] The present invention belongs to the technical field of air purification, and in particular relates to the application of a supported catalyst in catalyzing a catalytic oxidation reaction of ammonia and ozone, and a method for catalytically purifying ammonia. Background Art

[0002] Ammonia (NH3), a highly irritating alkaline gas, poses a series of serious risks to human health and the environment. NH3 in residential homes primarily originates from concrete antifreeze containing urea and ammonia used during construction. Long-term exposure to excessive NH3 levels can irritate organs and even cause serious lung disease. In livestock and poultry farming, NH3 is produced from the decomposition of nitrogen-containing organic matter such as feces, urine, bedding, and feed. Prolonged exposure of livestock and poultry in barns containing ammonia can severely irritate their mucous membranes, leading to respiratory illnesses and significantly reduced productivity. Furthermore, atmospheric emissions of ammonia can cause serious environmental problems such as haze, photochemical smog, and the greenhouse effect.

[0003] Currently, ammonia treatment methods include absorption, adsorption, combustion, and catalytic oxidation. Catalytic oxidation is widely used, but its catalyst activation temperature is high, requiring approximately 200°C to exhibit adequate activity. This limits its application in indoor and livestock farming applications. Summary of the Invention

[0004] The present invention aims to provide a method for catalytically purifying ammonia using a supported catalyst in a catalytic oxidation reaction between ammonia and ozone. The method provided by the present invention has a low catalyst activation temperature and mild temperature conditions for the catalytic oxidation reaction of ammonia, and can be widely used for catalytic purification of ammonia indoors and in livestock and poultry farming.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] The present invention provides an application of a supported catalyst in catalyzing a catalytic oxidation reaction of ammonia and ozone. The supported catalyst comprises a metal oxide support and an active component supported on the metal oxide support, wherein the active component is metallic silver. The temperature of the catalytic oxidation reaction is ≤40°C.

[0007] Preferably, the metal oxide support includes one or more of Al2O3, TiO2 and CeO2.

[0008] The present invention provides a method for catalytically purifying ammonia, comprising the following steps:

[0009] A supported catalyst is used to catalyze a catalytic oxidation reaction of ammonia and ozone in a mixed gas to obtain a mixed gas in which the ammonia is purified; the supported catalyst includes a metal oxide support and an active component supported on the metal oxide support, wherein the active component is metallic silver; the temperature of the catalytic oxidation reaction is ≤40°C.

[0010] Preferably, the volume ratio of ammonia to ozone in the mixed gas is 1 to 4:1.

[0011] Preferably, the ammonia content in the mixed gas is 50 to 1000 ppm.

[0012] Preferably, the mixed gas further comprises oxygen; the volume content of oxygen in the mixed gas is 10-20%.

[0013] Preferably, the temperature of the catalytic oxidation reaction is 10-40° C. and the relative humidity is 10-80%;

[0014] The reaction space velocity of the supported catalyst is 60,000 to 150,000 h -1 .

[0015] Preferably, the metal oxide support includes one or more of Al2O3, TiO2 and CeO2.

[0016] Preferably, the preparation method of the supported catalyst comprises the following steps:

[0017] impregnating a water-soluble silver precursor, a metal oxide support and water to obtain an impregnated support;

[0018] The impregnated support is calcined to obtain the supported catalyst.

[0019] Preferably, the mass percentage of the silver element in the water-soluble silver precursor to the metal oxide support is 0.5 to 5%;

[0020] The immersion temperature is 20 to 60° C. and the immersion time is 1 to 5 hours;

[0021] The calcination temperature is 400-600° C., and the calcination time is 2-5 hours.

[0022] The present invention provides the use of a supported catalyst for catalyzing the catalytic oxidation reaction of ammonia and ozone. The supported catalyst comprises a metal oxide support and an active component supported on the metal oxide support, wherein the active component is metallic silver. The temperature of the catalytic oxidation reaction is ≤40°C. The present invention uses metallic silver as the active component of the catalyst and ozone as the oxidant, effectively lowering the catalyst activation temperature. The catalytic oxidation reaction of ammonia and ozone can be achieved at a temperature of ≤40°C, thereby simultaneously purifying both ammonia and ozone. The results of the examples demonstrate that the present invention can achieve 100% purification of ammonia with an N2 selectivity of over 90%. Therefore, the present invention is widely applicable to the catalytic purification of ammonia in indoor and livestock and poultry farming environments.

[0023] At the same time, the present invention uses a supported catalyst and an ozone oxidant in synergy, and has good sulfur resistance. When used, when the hydrogen sulfide content reaches 100 ppm, it has no effect on the catalytic oxidation reaction of ammonia and ozone, and can achieve effective purification of ammonia under sulfur-containing conditions.

[0024] The present invention provides a method for catalytically purifying ammonia, comprising the following steps: using a supported catalyst to catalyze an oxidation reaction between ammonia and ozone in a mixed gas to produce a purified ammonia mixed gas; the supported catalyst comprises a metal oxide support and an active component supported on the metal oxide support, wherein the active component is metallic silver; and the catalytic oxidation reaction is performed at a temperature of 40°C or less. The method uses metallic silver as the active component of the catalyst and ozone as the oxidant, thereby effectively lowering the catalyst activation temperature. The catalytic oxidation reaction of ammonia and ozone can be achieved at a temperature of 40°C or less, thereby achieving simultaneous purification of ammonia and ozone in the mixed gas. Results from the examples demonstrate that the method can achieve 100% purification of ammonia with an N2 selectivity of over 90%. Therefore, the method is widely applicable to catalytic purification of ammonia in indoor and livestock and poultry farming environments.

[0025] At the same time, the method for catalytically purifying ammonia provided by the present invention has good sulfur resistance. When the content of hydrogen sulfide in the mixed gas reaches 100 ppm, the ammonia in the mixed gas can still be effectively purified.

[0026] Furthermore, in the present invention, the volume ratio of ammonia to ozone in the mixed gas is 1 to 4:1. Within the above volume ratio range of ammonia to ozone, the present invention can achieve 100% purification of ammonia and also fully purify ozone, with a purification rate of 100%.

[0027] Furthermore, in the present invention, the catalytic oxidation reaction temperature is 10-40°C and the relative humidity is 10-80%. The ammonia purification reaction provided by the present invention can proceed under mild reaction temperature conditions and a wide range of relative humidity conditions. The supported catalyst used in the method provided by the present invention has excellent water resistance, thus being widely applicable for catalytic purification of ammonia indoors and in livestock and poultry farming.

[0028] Furthermore, in the present invention, the metal oxide support comprises one or more of Al2O3, TiO2 and CeO2. The supported catalyst used in the present invention has a safe composition, a simple structure, and an easily available support, and is easy to promote and apply on a large scale, thus having good application prospects.

[0029] Furthermore, in the present invention, the method for preparing the supported catalyst comprises the following steps: mixing a water-soluble silver precursor, a metal oxide support, and water for impregnation to obtain an impregnated support; and calcining the impregnated support to obtain the supported catalyst. The catalyst preparation method provided by the present invention is simple, low-cost, and readily applicable on a large scale, with promising application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Activity test result graphs of Example 1 and Comparative Example 1 of the present invention, including NH3 conversion result graph, O3 conversion result graph, and N2 selectivity result graph;

[0031] Figure 2 Result graphs of the catalyst stability test described in Example 1 of the present invention, including graphs of NH3 conversion rate, O3 conversion rate, and N2 selectivity;

[0032] Figure 3 Result graphs of the sulfur resistance test of the catalyst described in Example 1 of the present invention, including graphs of NH3 conversion rate, O3 conversion rate, and N2 selectivity;

[0033] Figure 4 Result diagrams of NH3 conversion and N2 selectivity in Comparative Examples 2 and 3 of the present invention are shown. DETAILED DESCRIPTION

[0034] The present invention provides an application of a supported catalyst in catalyzing a catalytic oxidation reaction of ammonia and ozone. The supported catalyst comprises a metal oxide support and an active component supported on the metal oxide support, wherein the active component is metallic silver. The temperature of the catalytic oxidation reaction is ≤40°C.

[0035] In the present invention, unless otherwise specified, all preparation raw materials / components are commercially available products well known to those skilled in the art.

[0036] In the present invention, the metal oxide support preferably includes one or more of Al2O3, TiO2 and CeO2, more preferably one or two of Al2O3, TiO2 and CeO2, and in embodiments may be Al2O3, TiO2 or CeO2.

[0037] In the present invention, the active component of the supported catalyst is preferably metallic silver. The metallic silver is elemental silver. The mass percentage of the metallic silver in the metal oxide support is preferably 0.5-5%, and in the embodiment, it can be 1% or 2%.

[0038] In the present invention, the method for preparing the supported catalyst preferably comprises the following steps:

[0039] impregnating a water-soluble silver precursor, a metal oxide support and water to obtain an impregnated support;

[0040] The impregnated support is calcined to obtain the supported catalyst.

[0041] The present invention involves impregnating a water-soluble silver precursor, a metal oxide support, and water to obtain an impregnated support. The present invention does not require the specific type of the water-soluble silver precursor; any water-soluble silver precursor known in the art may be used. In the present invention, the water-soluble silver precursor may be silver nitrate. The mass percentage of silver in the water-soluble silver precursor relative to the metal oxide support is preferably 0.5-5%, and in embodiments, may be 1% or 2%. The mixing preferably comprises the following steps: dissolving the water-soluble silver precursor in a portion of the water to obtain a silver precursor solution; dispersing the metal oxide support in the remaining water to obtain a metal oxide support solution; and mixing the metal oxide support solution with the silver precursor solution. The ratio of the mass of the metal oxide support to the volume of the remaining water is preferably 1-2 g:50 mL. The impregnation temperature is preferably 20-60°C, more preferably 20-30°C, and the impregnation time is preferably 1-5 hours, more preferably 2-4 hours. The impregnation is preferably performed with stirring. In the present invention, after the impregnation is completed, the impregnation liquid is directly obtained. The present invention preferably removes the solvent from the impregnation liquid to obtain a solid product; the solid product is dried to obtain the impregnated carrier. The method of removing the solvent is preferably vacuum rotary evaporation. The temperature of the vacuum rotary evaporation is preferably 60-90°C, and the rotation speed is preferably 80-100r / min, more preferably 80-90r / min. The present invention has no special requirements for the time of the vacuum rotary evaporation, as long as no water vapor is generated in the rotary evaporation bottle and the surface of the material is dry. The drying is preferably carried out in an oven, the drying temperature is preferably 80-110°C, more preferably 95-100°C, and the time is preferably 10-16h, more preferably 12-16h.

[0042] After obtaining the impregnated support, the present invention calcines the impregnated support to obtain the supported catalyst. In the present invention, the calcination is preferably performed in a muffle furnace. The calcination atmosphere is preferably air. The calcination temperature is preferably 400-600°C, and in some embodiments, it can be 500°C. The calcination time is preferably 2-5 hours, and in some embodiments, it can be 3 hours.

[0043] The present invention provides a method for catalytically purifying ammonia, comprising the following steps:

[0044] A supported catalyst is used to catalyze a catalytic oxidation reaction of ammonia and ozone in a mixed gas to obtain a mixed gas in which the ammonia is purified; the supported catalyst includes a metal oxide support and an active component supported on the metal oxide support, wherein the active component is metallic silver; the temperature of the catalytic oxidation reaction is ≤40°C.

[0045] In the present invention, the composition and preparation method of the supported catalyst have been described above and will not be repeated here.

[0046] In the present invention, the volume ratio of ammonia to ozone in the mixed gas is preferably 1 to 4:1, more preferably 2 to 3:1, and in an embodiment, it can be 2.5:1. The ammonia content in the mixed gas is preferably 50 to 1000 ppm, and in an embodiment, it can be 500 ppm. The ozone content can be 200 ppm.

[0047] As one or more embodiments of the present invention, the mixed gas further comprises oxygen; the volume content of oxygen in the mixed gas is preferably 10-20%, and in the embodiment can be 20%.

[0048] In the present invention, the mixed gas may further include nitrogen, which is a balance gas.

[0049] In one or more embodiments of the present invention, the mixed gas may further include hydrogen sulfide. The content of hydrogen sulfide in the mixed gas is preferably ≤200 ppm, and in an embodiment, may be 100 ppm. The method for catalytically purifying ammonia provided by the present invention can achieve efficient purification of ammonia even when the mixed gas contains hydrogen sulfide, and has good sulfur resistance.

[0050] In the present invention, the temperature of the catalytic oxidation reaction is preferably 10 to 40° C., more preferably 20 to 30° C. The relative humidity of the catalytic oxidation reaction is preferably 10 to 80%, more preferably 30 to 60%.

[0051] In the present invention, the reaction space velocity of the supported catalyst is preferably 60,000 to 150,000 h-1 , more preferably 80000~120000h -1 , in the embodiment, it can be 120000h -1 .

[0052] In order to further illustrate the present invention, the technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0053] Example 1:

[0054] This embodiment provides a method for preparing a supported catalyst, which specifically includes the following steps:

[0055] Weigh 10g of Al2O3 powder, slowly pour it into a beaker filled with 500mL of deionized water, stir at room temperature for 0.5h to obtain an alumina mixture; add 2mL of silver nitrate aqueous solution containing 0.2g of Ag element to the obtained alumina mixture, stir at room temperature for 2h, stir and impregnate thoroughly, transfer to a vacuum rotary evaporator and dry at 80℃ to remove the solvent, with a rotation speed of 90r / min. The obtained powder sample is placed in an oven at 100℃ and dried for 12h to obtain alumina loaded with active component Ag, and then the alumina loaded with active component Ag is calcined at 500℃ in a muffle furnace for 3h to obtain a supported catalyst, which includes an alumina carrier and metallic silver loaded on the alumina carrier, and is recorded as Ag / Al2O3 catalyst (in Figures 2-3 In the embodiment, it is represented as 2Ag / Al2O3), wherein the mass percentage of metallic silver in the alumina carrier is 2%.

[0056] This embodiment provides a method for catalytically purifying ammonia, which specifically includes the following steps: loading the Ag / Al2O3 catalyst prepared in this embodiment into a fixed bed, and performing a catalytic oxidation reaction through a mixed gas from one end of a fixed bed continuous evaluation device. The mixed gas consists of ammonia, ozone, oxygen, and nitrogen, with an NH3 content of 500ppm, an O3 content of 200ppm, an O2 volume content of 20%, and the rest being nitrogen, with N2 serving as a balance gas. The conditions for the catalytic oxidation reaction in this embodiment include: a reaction space velocity of the Ag / Al2O3 catalyst of 120,000h -1 , the temperature of the catalytic oxidation reaction is 30°C, and the relative humidity of the catalytic oxidation reaction is 30%.

[0057] Example 2:

[0058] This embodiment provides a method for preparing a supported catalyst, which specifically includes the following steps:

[0059] Weigh 10g of TiO2 powder, slowly pour it into a beaker filled with 500mL of deionized water, stir at room temperature for 0.5h to obtain a titanium dioxide mixture; add 2mL of silver nitrate aqueous solution containing 0.2g of Ag element to the obtained titanium dioxide mixture, stir at room temperature for 2h, and after sufficient stirring and impregnation, transfer it to a vacuum rotary evaporator to dry at 80°C to remove the solvent, with a rotation speed of 90r / min. The obtained powder sample is placed in an oven at 100°C and dried for 12h to obtain titanium dioxide loaded with the active component Ag. The titanium dioxide loaded with the active component Ag is then calcined at 500°C in a muffle furnace for 3h to obtain a loaded catalyst. The loaded catalyst includes a titanium oxide carrier and metallic silver loaded on the titanium oxide carrier, which is recorded as Ag / TiO2 catalyst, wherein the mass percentage of metallic silver in the titanium oxide carrier is 2%.

[0060] This embodiment provides a method for catalytically purifying ammonia, which specifically includes the following steps: loading the Ag / TiO2 catalyst prepared in this embodiment into a fixed bed, and performing a catalytic oxidation reaction through a mixed gas from one end of a fixed bed continuous evaluation device. The mixed gas consists of ammonia, ozone, oxygen, and nitrogen, with an NH3 content of 500ppm, an O3 content of 200ppm, an O2 volume content of 20%, and the rest being nitrogen, with N2 serving as a balance gas. The conditions for the catalytic oxidation reaction in this embodiment include: a reaction space velocity of the Ag / TiO2 catalyst of 120,000h -1 , the temperature of the catalytic oxidation reaction is 30°C, and the relative humidity of the catalytic oxidation reaction is 30%.

[0061] Example 3:

[0062] This embodiment provides a method for preparing a supported catalyst, which specifically includes the following steps:

[0063] Weigh 10g of CeO2 powder, slowly pour it into a beaker filled with 500mL of deionized water, stir at room temperature for 0.5h to obtain a cerium dioxide mixture; add 2mL of silver nitrate aqueous solution containing 0.2g of Ag to the obtained cerium dioxide mixture, stir at room temperature for 2h, and after sufficient stirring and impregnation, transfer it to a vacuum rotary evaporator to dry at 80°C to remove the solvent, with a rotation speed of 90r / min. The obtained powder sample is placed in an oven at 100°C and dried for 12h to obtain cerium dioxide loaded with active component Ag. The cerium dioxide loaded with active component Ag is then calcined at 500°C in a muffle furnace for 3h to obtain a loaded catalyst. The loaded catalyst includes a cerium oxide carrier and metallic silver loaded on the cerium oxide carrier, which is recorded as Ag / CeO2 catalyst, wherein the mass percentage of metallic silver in the cerium oxide carrier is 2%.

[0064] This embodiment provides a method for catalytically purifying ammonia, which specifically includes the following steps: loading the Ag / CeO2 catalyst prepared in this embodiment into a fixed bed, and performing a catalytic oxidation reaction through a mixed gas from one end of a fixed bed continuous evaluation device. The mixed gas consists of ammonia, ozone, oxygen, and nitrogen, with an NH3 content of 500ppm, an O3 content of 200ppm, an O2 volume content of 20%, and the rest being nitrogen, with N2 serving as a balance gas. The conditions for the catalytic oxidation reaction in this embodiment include: a reaction space velocity of the Ag / CeO2 catalyst of 120,000h -1 , the temperature of the catalytic oxidation reaction is 30°C, and the relative humidity of the catalytic oxidation reaction is 30%.

[0065] Comparative Example 1:

[0066] The preparation method of the supported catalyst used in this comparative example is the same as that in Example 1.

[0067] This comparative example provides a method for catalytically purifying ammonia, which specifically includes the following steps: the Ag / Al2O3 catalyst prepared in this example is loaded into a fixed bed, and a catalytic oxidation reaction is carried out through a mixed gas from one end of a fixed bed continuous evaluation device. The mixed gas consists of ammonia, ozone, oxygen and nitrogen, with an NH3 content of 500ppm, an O3 content of 0, an O2 volume content of 20%, and the rest being nitrogen, with N2 serving as a balance gas. The conditions for the catalytic oxidation reaction in this comparative example include: the reaction space velocity of the Ag / Al2O3 catalyst is 120,000h -1 , the temperature of the catalytic oxidation reaction is 30°C, and the relative humidity of the catalytic oxidation reaction is 30%.

[0068] Comparative Example 2:

[0069] This comparative example provides a method for preparing a supported catalyst, which specifically comprises the following steps:

[0070] Weigh 10g of Al2O3 powder, slowly pour it into a beaker filled with 500mL of deionized water, and stir at room temperature for 0.5h to obtain an alumina mixture; add an aqueous manganese nitrate solution containing 1g of Mn element (the mass content of manganese nitrate in the aqueous manganese nitrate solution is 50wt%) to the obtained alumina mixture, stir at room temperature for 2h, and after sufficient stirring and impregnation, transfer it to a vacuum rotary evaporator and dry it at 80°C to remove the solvent at a rotation speed of 90r / min. The obtained powder sample is placed in an oven at 100°C and dried for 12h to obtain alumina loaded with the active component Mn. The alumina loaded with the active component Mn is then calcined at 500°C in a muffle furnace for 3h to obtain a supported catalyst. The supported catalyst includes an alumina carrier and manganese oxide supported on the alumina carrier, which is recorded as Mn / Al2O3 catalyst, wherein the manganese element in the manganese oxide accounts for 10% by mass of the alumina carrier.

[0071] This comparative example provides a method for catalytically purifying ammonia, which specifically includes the following steps: loading the Mn / Al2O3 catalyst prepared in this comparative example into a fixed bed, and performing a catalytic oxidation reaction through a mixed gas from one end of a fixed bed continuous evaluation device. The mixed gas consists of ammonia, ozone, oxygen and nitrogen, with an NH3 content of 200ppm, an O3 content of 220ppm, an O2 volume content of 20%, and the rest being nitrogen, with N2 serving as a balance gas. The conditions for the catalytic oxidation reaction in this comparative example include: a reaction space velocity of the Mn / Al2O3 catalyst of 120,000h -1 , the temperature of the catalytic oxidation reaction is 30°C, and the relative humidity of the catalytic oxidation reaction is 30%.

[0072] Comparative Example 3:

[0073] This comparative example provides a method for preparing a supported catalyst, which specifically comprises the following steps:

[0074] Weigh 10g of TiO2 powder, slowly pour it into a beaker filled with 500mL of deionized water, stir at room temperature for 0.5h to obtain a titanium dioxide mixture; add a manganese nitrate aqueous solution containing 1g of Mn element (the mass content of manganese nitrate in the manganese nitrate aqueous solution is 50wt%) to the obtained titanium dioxide mixture, stir at room temperature for 2h, and after sufficient stirring and impregnation, transfer it to a vacuum rotary evaporator and dry it at 80°C to remove the solvent at a rotation speed of 90r / min. The obtained powder sample is placed in an oven and dried at 100°C for 12h to obtain titanium dioxide loaded with the active component Mn. The titanium dioxide loaded with the active component Mn is then calcined at 500°C in a muffle furnace for 3h to obtain a supported catalyst. The supported catalyst includes a titanium oxide carrier and manganese oxide loaded on an alumina carrier, which is recorded as Mn / TiO2 catalyst, wherein the manganese element in the manganese oxide accounts for 10% by mass of the titanium oxide carrier.

[0075] This comparative example provides a method for catalytically purifying ammonia, which specifically includes the following steps: loading the Mn / TiO2 catalyst prepared in this comparative example into a fixed bed, and performing a catalytic oxidation reaction through a mixed gas from one end of a fixed bed continuous evaluation device. The mixed gas consists of ammonia, ozone, oxygen and nitrogen, with an NH3 content of 200ppm, an O3 content of 220ppm, an O2 volume content of 20%, and the rest being nitrogen, with N2 serving as a balance gas. The conditions for the catalytic oxidation reaction in this comparative example include: a reaction space velocity of the Mn / TiO2 catalyst of 120,000h -1 , the temperature of the catalytic oxidation reaction is 30°C, and the relative humidity of the catalytic oxidation reaction is 30%.

[0076] Figure 1 This is a graph showing the activity test results of the method for catalytically purifying ammonia provided in Example 1 of the present invention and Comparative Example 1. Figure 1 The left picture is the result of NH3 conversion in mixed gas. Figure 1 The middle figure is the O3 conversion rate result diagram. Figure 1 The right figure in the figure is the N2 selectivity result. Figure 1 As can be seen from the left figure, the mixed gas in Comparative Example 1 does not contain ozone and does not react at 30°C. However, the embodiment uses ozone as the oxidant, and a catalytic oxidation reaction can occur at a reaction temperature of 30°C, with NH3 conversion rates close to 100%, O3 conversion rates close to 100%, and N2 selectivity ≥ 90%.

[0077] Figure 2 This is a graph showing the results of the stability test of the supported catalyst prepared in Example 1 of the present invention. Figure 2 The left figure is the NH3 conversion rate result within the reaction time of 0 to 12 hours. Figure 2 The middle figure is the O3 conversion result within the reaction time of 0 to 12 hours. Figure 2 The right figure is the N2 selectivity result diagram within the reaction time of 0 to 12 hours. Figure 2 It can be seen that the NH3 conversion rate, O3 conversion rate and N2 selectivity of the supported catalyst prepared in Example 1 remain stable within the reaction time of 0 to 12 h, proving that the supported catalyst provided by the present invention has high catalytic stability when catalyzing the catalytic oxidation reaction of ammonia and ozone.

[0078] Figure 3 The test results of the sulfur resistance of the catalyst provided in Example 1 of the present invention are as follows: the method for catalytic purification of ammonia provided in Example 1 is adopted, the catalytic oxidation reaction time is 1h, and the composition of the mixed gas is replaced by: the mixed gas consists of H2S, ammonia, ozone, oxygen and nitrogen, the H2S content is 100ppm, the NH3 content is 500ppm, the O3 content is 200ppm, the volume content of O2 is 20%, and the rest is nitrogen, with N2 as the balance gas. The other reaction conditions are the same as those in Example 1. Figure 2 and Figure 3 It can be seen that when the mixed catalyst contains H2S, the NH3 conversion rate, O3 conversion rate and N2 selectivity still maintain a very high level, indicating that the supported catalyst provided by Example 1 of the present invention has good anti-sulfurization performance.

[0079] Figure 4 The NH3 conversion rate of the supported catalyst prepared in Comparative Examples 2 and 3 ( Figure 4 Left figure in), N2 selectivity ( Figure 4 (right figure in the figure), by Figure 4 It can be seen that the supported catalysts prepared by Comparative Examples 2 and 3 have poor catalytic activity and poor stability.

[0080] From the above examples, it can be seen that the method for catalytic purification of ammonia provided by the present invention uses a non-toxic and harmless component of a supported catalyst, has extremely low cost, and a simple and easy preparation process, which can be used for large-scale production. The method for catalytic purification of ammonia provided by the present invention uses O3 as an oxidant, effectively lowering the activation temperature of the catalyst, and can achieve 100% purification of NH3 and more than 90% N2 selectivity at room temperature, and can also achieve complete decomposition of O3 without causing secondary pollution. The supported catalyst in the method for catalytic purification of ammonia provided by the present invention has excellent sulfur and water resistance and a long service life, and has significant practical application value.

[0081] Although the above embodiment provides a detailed description of the present invention, it is only a part of the embodiments of the present invention, not all of the embodiments. Other embodiments can be obtained based on this embodiment without creativity, and these embodiments all fall within the scope of protection of the present invention.

Claims

1. Use of a supported catalyst in catalyzing the catalytic oxidation reaction of ammonia and ozone, characterized in that: The supported catalyst comprises a metal oxide support and an active component supported on the metal oxide support, wherein the active component is metallic silver; and the temperature of the catalytic oxidation reaction is ≤40°C.

2. The use according to claim 1, characterized in that The metal oxide support includes one or more of Al2O3, TiO2 and CeO2.

3. A method for catalytically purifying ammonia, characterized in that: The following steps are involved: A supported catalyst is used to catalyze a catalytic oxidation reaction of ammonia and ozone in a mixed gas to obtain a mixed gas in which the ammonia is purified; the supported catalyst includes a metal oxide support and an active component supported on the metal oxide support, wherein the active component is metallic silver; the temperature of the catalytic oxidation reaction is ≤40°C.

4. The method for catalytically purifying ammonia according to claim 3, characterized in that: The volume ratio of ammonia to ozone in the mixed gas is 1 to 4:

1.

5. The method for catalytically purifying ammonia according to claim 3 or 4, characterized in that: The content of ammonia in the mixed gas is 50 to 1000 ppm.

6. The method for catalytically purifying ammonia according to claim 3 or 4, characterized in that: The mixed gas also includes oxygen; the volume content of oxygen in the mixed gas is 10-20%.

7. The method for catalytically purifying ammonia according to claim 3 or 4, characterized in that: The temperature of the catalytic oxidation reaction is 10-40°C and the relative humidity is 10-80%; The reaction space velocity of the supported catalyst is 60,000 to 150,000 h -1 .

8. The method for catalytically purifying ammonia according to claim 3, characterized in that: The metal oxide support includes one or more of Al2O3, TiO2 and CeO2.

9. The method for catalytically purifying ammonia according to claim 3 or 8, characterized in that: The preparation method of the supported catalyst comprises the following steps: impregnating a water-soluble silver precursor, a metal oxide support and water to obtain an impregnated support; The impregnated support is calcined to obtain the supported catalyst.

10. The method for catalytically purifying ammonia according to claim 9, characterized in that: The mass percentage of the silver element in the water-soluble silver precursor to the metal oxide support is 0.5 to 5%; The immersion temperature is 20 to 60° C. and the immersion time is 1 to 5 hours; The calcination temperature is 400-600° C., and the calcination time is 2-5 hours.

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