CuO-doped nitrogen-doped carbon-based catalyst for removing PH3 and preparation method of CuO-doped nitrogen-doped carbon-based catalyst

Abstract

The invention provides a CuO nitrogen-doped carbon-based catalyst for removing PH3 and a preparation method thereof.The preparation method comprises the steps that activated carbon particles are subjected to pretreatment mainly including washing and then soaked in an organic solution of melamine for soaking treatment, then roasting treatment is carried out under the inert atmosphere condition, nitrogen-doped activated carbon is prepared, and the CuO nitrogen-doped carbon-based catalyst for removing PH3 is obtained. And dipping the nitrogen-doped activated carbon in a copper salt solution for dipping treatment, and finally performing roasting treatment under an inert atmosphere condition to prepare the CuO nitrogen-doped carbon-based catalyst. According to the catalyst, melamine is specifically selected as a nitrogen doping source, it is found that dissolution of active components in the regeneration process of the prepared catalyst can be effectively prevented through secondary roasting treatment, and surprisingly, the PH3 removal amount reaches 500 mg / g or above under the condition that the removal efficiency of the prepared catalyst is not lower than 80%; and after regeneration, the removal amount of PH3 can still reach 80.97% of that of a fresh catalyst.

Description

Technical Field

[0001] The present invention belongs to the field of industrial tail gas removal PH 3 The technical field of catalysts relates to a method for removing PH 3 CuO@ nitrogen-doped carbon-based catalyst and its preparation method, specifically related to a method for removing PH 3 A CuO@nitrogen-doped carbon-based catalyst capable of preventing active components from dissolving out and a preparation method thereof. Background Art

[0002] With the rapid development of my country's yellow phosphorus industry, the problem of yellow phosphorus tail gas treatment has become increasingly prominent. The carbon monoxide (CO) content in yellow phosphorus tail gas is as high as 85% to 95%. If the yellow phosphorus tail gas is not recycled, it will cause a waste of resources. In addition, the highly toxic phosphine (PH 3 ) content is as high as 750-1000 mg / m 3 , PH 3 It not only harms human health and the natural environment, but also absorbs and re-releases infrared radiation, retains heat in the atmosphere, and competes with hydroxyl radicals to increase the concentration of greenhouse gases, posing a serious threat to the environment and production safety. Therefore, how to effectively remove phosphine from yellow phosphorus tail gas has become an urgent problem to be solved in my country's yellow phosphorus industry.

[0003] In recent years, people have been working hard to develop effective PH 3 Purification strategy, currently, PH 3 The removal technology is mainly divided into two types: wet method and dry method. The wet method has strong treatment capacity and high removal efficiency, but it produces more wastewater and is prone to secondary pollution. The dry method is mainly based on catalytic oxidation. This method is easy to operate, has high purification efficiency, and the catalyst can be recycled, but there are problems such as limited catalyst adsorption capacity and easy deactivation. The adsorption catalytic oxidation method is generally to convert pH 3 First adsorb on the catalyst surface, then use the strong oxidant on the catalyst surface to reduce the pH 3 The reaction temperature of this method is usually below 200°C, with low energy consumption, few by-products, and it can effectively prevent the cracking of raw gas under low temperature conditions. Therefore, it has become the current method for removing PH 3 The main technology.

[0004] In the catalytic oxidation method, the mainstream and cost-effective way is to use supported metal oxide catalysts. Studies have found that activated carbon loaded with copper oxide is an ideal PH 3 However, the existing copper oxide-loaded activated carbon catalysts 3 In terms of removal, there are generally problems such as low catalytic performance, small removal capacity (removal amount does not exceed 200 mg / g) and difficulty in regeneration after deactivation. This is a key issue that needs to be solved.

[0005] Doping modification is currently a common method to improve the oxidation removal pH of copper oxide-loaded activated carbon catalysts. 3 Common strategies for improving the effect. Among them, it has been proven that the catalytic performance of the catalyst can be greatly improved by doping and modifying thiophene or thiophene derivatives as a sulfur source. For example, the Chinese invention patent "A sulfur-doped carbon material and its preparation method and application" (CN114105122B, Sinopec) discloses a technology for doping and modifying activated carbon by using thiophene as a sulfur source.

[0006] Although the above-mentioned existing research can effectively improve the removal effect of catalysts, it generally has the defects of complex preparation process and high production cost. In addition, thiophene or thiophene derivatives themselves have certain toxicity, so they have high requirements for the production environment. At present, they are mainly used in high-cost and high-value fields such as batteries. 3 The catalyst removes pH 3 Most of the effects can only be shown in aerobic conditions. However, high oxygen content in industrial exhaust gas can easily bring risks such as explosion. Therefore, there is still a lack of methods that can deeply remove pH under low temperature and oxygen-free conditions. 3 , and it is a practical method suitable for industrial applications, which is simple and highly operable.

[0007] In order to solve the above problems, the inventor of the present invention has previously applied for a patent for "Sulfur-doped carbon-based dephosphorization of copper oxide" 3 Catalyst and preparation method thereof (CN117427656A)" discloses that activated carbon particles are first subjected to a pretreatment mainly including washing, and then immersed in a copper nitrate solution with a mass concentration of 12-15wt% for ultrasonic immersion treatment for 1.5-2.5h. After the time is up, the activated carbon loaded with copper nitrate is washed and dried to obtain the activated carbon, which is then mixed with elemental sulfur powder in a mass ratio of 1: (0.51-0.52) as a mixed material, and finally the mixed material is calcined in a tubular furnace to prepare a sulfur-doped carbon-based dephosphorization catalyst loaded with copper oxide. 3 Catalyst. The preparation method has better catalytic performance by improving the specific process of heating mode in roasting treatment. When the removal efficiency is not less than 80%, the PH 3 The removal amount reaches more than 200 mg / g, which is much better than similar products recorded in existing literature in this field.

[0008] However, in the research work carried out by the inventors including the above patent technology, it is believed that the pH of the catalyst 3There is still room for improvement in the removal amount, and the more complicated heating procedure in the calcination process should be simplified to better meet the needs of industrialization. In addition, it was found in this process that the active components of the copper oxide-loaded catalyst were easily dissolved during the regeneration process, resulting in a pH value of the regenerated catalyst. 3 The removal amount further decreases, which invisibly increases the cost of its recycling and the need for additional water treatment. Summary of the invention

[0009] In order to solve the above-mentioned problems in the prior art, the present invention provides a method for removing pH 3 The CuO@nitrogen-doped carbon-based catalyst and its preparation method are described. Melamine is specifically selected as the nitrogen-doping source for the catalyst. It is found that the dissolution of the active components of the prepared catalyst during the regeneration process can be effectively prevented by secondary calcination treatment. Surprisingly, the prepared CuO@nitrogen-doped carbon-based catalyst has a pH of 80% under the condition of a removal efficiency of not less than 80%. 3 The removal amount reaches more than 500mg / g, and the pH after regeneration 3 The removal amount can still reach 80.97% of the fresh catalyst.

[0010] To achieve the above objectives, the present invention is implemented by adopting a technical solution consisting of the following technical measures.

[0011] The present invention provides a method for removing pH 3 The preparation method of the CuO@ nitrogen-doped carbon-based catalyst mainly comprises the following steps:

[0012] (1) After the activated carbon particles are pretreated mainly by washing, they are used as pretreated activated carbon for later use;

[0013] (2) immersing the pretreated activated carbon obtained in step (1) in an organic solution having a melamine concentration of 0.006 to 0.0167 g / ml for at least 24 hours; after the time is up, drying to obtain melamine-loaded activated carbon;

[0014] (3) calcining the melamine-loaded activated carbon obtained in step (2) under inert atmosphere conditions, heating the temperature to 800-1000° C. at a heating rate of 9.5-10.5° C. / min and maintaining the temperature for 1.5-2.5 h to prepare nitrogen-doped activated carbon;

[0015] (4) immersing the nitrogen-doped activated carbon obtained in step (3) in a copper salt solution having a mass percentage concentration of 8 to 12 wt% for 1.5 to 2.5 h; after the time is up, washing to remove the residual copper salt solution, and drying to obtain the copper salt-loaded nitrogen-doped activated carbon;

[0016] (5) The copper salt-loaded nitrogen-doped activated carbon obtained in step (4) is calcined under inert atmosphere conditions, heated to 500-600° C. at a heating rate of 4.5-5.5° C. / min and kept at this temperature for 2-3 h to prepare a CuO@nitrogen-doped carbon-based catalyst.

[0017] In this article, the activated carbon particles in step (1) are conventional commercially available activated carbon particles, preferably using the activated carbon particles in the technical field (industrial tail gas removal PH 3 The activated carbon particles of general specifications for catalysts usually have a particle size of 4 to 10 mm.

[0018] In this article, the activated carbon particles in step (1) are usually attached with residual impurities or other impurities / stains, which will affect the catalytic performance of the catalyst prepared subsequently, especially the commercially available activated carbon particles. Based on this, it is necessary to pre-treat the activated carbon particles mainly including washing, and the pre-treating mainly including washing can be a pre-treating method known in the art, and those skilled in the art can perform specific operations according to conventional production processes or methods described in the prior art.

[0019] In one of the technical solutions, in order to improve the pretreatment effect on activated carbon particles, the step (1) mainly includes a washing pretreatment, specifically: the activated carbon particles are washed with ultrapure water and then dried, then washed with alkaline, and then washed with ultrapure water and dried to obtain the pretreated activated carbon.

[0020] In the above technical solution, under laboratory conditions, alkali washing can be further preferably performed by immersing in alkali solution. The alkali solution can be selected from alkali solutions selected for conventional alkali washing, such as sodium hydroxide solution and potassium hydroxide solution, and the mass concentration of the alkali solution is preferably 5-7%; the specific immersion time can be preferably 12-14 hours at normal temperature and pressure.

[0021] It should be noted that the above technical solution mainly includes a washing pretreatment, the purpose of which is to remove residual impurities or other impurities / stains attached to the surface of the activated carbon particles. The above preferred pretreatment specific process steps are mainly carried out under laboratory conditions. In actual industrial production, the pretreatment method can be improved and replaced according to actual conditions and based on common knowledge.

[0022] In this article, the pretreated activated carbon in step (2) is immersed in an organic solution with a melamine mass concentration of 0.006 to 0.0167 g / ml for at least 24 hours, which is a conventional process for loading nitrogen source on activated carbon, wherein the amount of organic solution containing melamine is preferably 1 to 4 ml / g based on the mass of the activated carbon.

[0023] In this article, the melamine mass concentration in step (2) is an organic solution of 0.006-0.0167 g / ml, wherein the solvent is a conventional organic solvent capable of dissolving melamine, such as any one of methanol, acetic acid, and dimethylformamide.

[0024] In one of the technical solutions, the pretreated activated carbon in step (2) is immersed in an organic solution with a melamine mass concentration of 0.006 to 0.0167 g / ml for at least 24 hours, wherein the immersion treatment can be carried out by standing, or by conventional auxiliary process means such as mechanical stirring and ultrasonic treatment to increase the efficiency of the immersion treatment. Those skilled in the art should know that the immersion treatment is a conventional process method, and those skilled in the art can select a suitable immersion treatment method according to actual needs and actual process conditions.

[0025] Herein, the copper salt in step (4) is selected from conventional copper source raw materials for supporting copper oxide catalysts, such as any one of copper nitrate, copper acetate, copper sulfate, copper carbonate, and copper hydroxide. However, it should be noted that the specific solubility of the selected specific copper salt in water should be taken into consideration.

[0026] In one preferred technical solution, the copper salt in step (4) is copper nitrate.

[0027] In this article, the nitrogen-doped activated carbon in step (4) is immersed in a copper salt solution with a mass percentage concentration of 8 to 12 wt% for 1.5 to 2.5 hours, which is a conventional process for loading metal salts on activated carbon, wherein the amount of copper salt solution used, based on the mass of the activated carbon, is preferably 1.5 to 2.5 ml / g.

[0028] In one of the technical schemes, the nitrogen-doped activated carbon in step (4) is immersed in a copper salt solution with a mass percentage concentration of 8 to 12 wt% for 1.5 to 2.5 hours, wherein the impregnation treatment is preferably ultrasonic-assisted impregnation treatment, and its process parameters are preferably ultrasonic-assisted impregnation treatment with an ultrasonic frequency of 20 to 30 Hz and a temperature of 30 to 40°C.

[0029] In this article, the washing and drying are in accordance with the conventional principles of chemical processes, and those skilled in the art can perform specific operations according to common knowledge.

[0030] In the above technical solution, under laboratory conditions, washing is usually performed with ultrapure water for 3 times or more; drying is usually performed at 100-110° C. for at least 12 hours.

[0031] On the other hand, the present invention also provides a regeneration method for the above-mentioned CuO@nitrogen-doped carbon-based catalyst, which is to immerse the CuO@nitrogen-doped carbon-based catalyst in deionized water at a temperature of 35-55°C for 1-2 hours, and after drying, heat it to 200-300°C at a heating rate of 3-5°C / min in a dry air or pure oxygen atmosphere and keep it warm for 1.5-2.5 hours to obtain the regenerated CuO@nitrogen-doped carbon-based catalyst.

[0032] On the other hand, the CuO@ nitrogen-doped carbon-based catalyst provided by the present invention is used to remove PH from industrial tail gas. 3 , especially under anaerobic conditions, at pH 3 Gas concentration is 200~400mg / Nm 3 The catalytic reaction removes pH under the condition that the reaction temperature is at least 50°C. 3 .

[0033] The present invention has the following beneficial effects:

[0034] 1. The main inventive point of the present invention is that the catalyst specifically selects melamine as the nitrogen doping source, and it is found that the secondary calcination treatment can effectively prevent the dissolution of the active components of the prepared catalyst during the regeneration process. Surprisingly, the prepared CuO@ nitrogen-doped carbon-based catalyst has a pH of 80% when the removal efficiency is not less than 80%. 3 The removal amount reaches more than 500mg / g, and the pH after regeneration 3 The removal amount can still reach 80.97% of the fresh catalyst, which is much better than similar products recorded in existing literature in this field.

[0035] 2. The present invention has found that based on the specific selection of melamine as a nitrogen source combined with a secondary calcination treatment, the product performance is significantly higher than similar catalysts recorded in the current prior art, and is also much better than the technical effect in the inventor's prior invention patent application, and has excellent industrial value.

[0036] 3. The overall process of the present invention is simple, easy to operate, and can be directly applied to the current de-PH 3 The catalyst production process has excellent practicability, low cost and is easy to market as a superior product. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 The CuO@ nitrogen-doped carbon-based catalyst prepared in Example 1 of the present invention was 3 Dotted line graph of removal efficiency in removal tests.

[0038] Figure 2 The CuO@ nitrogen-doped carbon-based catalyst prepared in Example 1 of the present invention is used to remove pH 3Photo of a deactivated sample whose efficiency dropped below 80% after testing.

[0039] Figure 3 The following are comparison photos of the impregnation liquid in the regeneration process of Example 2 of the present invention and Comparative Example 3. The left side shows that after the deactivated CuO@ nitrogen-doped carbon-based catalyst was immersed in deionized water at 50°C for 1 hour, no obvious blue color was observed in the impregnation liquid; the right side shows that after the deactivated copper oxide-loaded activated carbon catalyst was immersed in deionized water at 50°C for 1 hour, the impregnation liquid was obviously blue, indicating that its active components were dissolved.

[0040] Figure 4 The pH of the CuO@ nitrogen-doped carbon-based catalyst regenerated in Example 2 of the present invention is 3 Dotted line graph of removal efficiency in removal tests.

[0041] Figure 5 The nitrogen-doped activated carbon prepared in Comparative Example 1 of the present invention was 3 Dotted line graph of removal efficiency in removal tests.

[0042] Figure 6 The copper oxide-loaded activated carbon catalyst prepared in Comparative Example 2 of the present invention was 3 Dotted line graph of removal efficiency in removal tests.

[0043] Figure 7 The copper oxide-loaded activated carbon catalyst prepared in Comparative Example 2 of the present invention is removed by PH 3 Photo of a deactivated comparison sample whose efficiency dropped below 80% after testing.

[0044] Figure 8 The copper oxide loaded activated carbon catalyst regenerated in Comparative Example 3 of the present invention is at pH 3 Dotted line graph of removal efficiency in removal tests. DETAILED DESCRIPTION

[0045] In order to further understand the present invention, the preferred embodiments of the present invention are described below in conjunction with examples, but it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the invention. Those skilled in the art can refer to the content of this article and appropriately improve the process parameters to achieve it. It is particularly important to point out that all similar substitutions and modifications are obvious to those skilled in the art, and they are all considered to be included in the present invention. The methods and applications of the present invention have been described through preferred embodiments, and relevant personnel can obviously change or appropriately change and combine the methods and applications described herein without departing from the content, spirit and scope of the present invention to implement and apply the technology of the present invention. Although it is believed that those of ordinary skill in the art fully understand the following terms, the following definitions are still stated to help illustrate the subject matter disclosed by the present invention.

[0046] The present invention provides a method for removing pH 3 The preparation method of the CuO@ nitrogen-doped carbon-based catalyst mainly comprises the following steps:

[0047] (1) After the activated carbon particles are pretreated mainly by washing, they are used as pretreated activated carbon for later use;

[0048] (2) immersing the pretreated activated carbon obtained in step (1) in an organic solution having a melamine concentration of 0.006 to 0.0167 g / ml for at least 24 hours; after the time is up, drying to obtain melamine-loaded activated carbon;

[0049] (3) calcining the melamine-loaded activated carbon obtained in step (2) under inert atmosphere conditions, heating the temperature to 800-1000° C. at a heating rate of 9.5-10.5° C. / min and maintaining the temperature for 1.5-2.5 h to prepare nitrogen-doped activated carbon;

[0050] (4) immersing the nitrogen-doped activated carbon obtained in step (3) in a copper salt solution having a mass percentage concentration of 8 to 12 wt% for 1.5 to 2.5 h; after the time is up, washing to remove the residual copper salt solution, and drying to obtain the copper salt-loaded nitrogen-doped activated carbon;

[0051] (5) The copper salt-loaded nitrogen-doped activated carbon obtained in step (4) is calcined under inert atmosphere conditions, heated to 500-600° C. at a heating rate of 4.5-5.5° C. / min and kept at this temperature for 2-3 h to prepare a CuO@nitrogen-doped carbon-based catalyst.

[0052] In this article, the activated carbon particles in step (1) are conventional commercially available activated carbon particles, preferably using the activated carbon particles in the technical field (industrial tail gas removal PH 3Catalyst) general specifications of activated carbon particles, in one embodiment, the particle size of the activated carbon particles is 4 to 10 mm.

[0053] In this article, the activated carbon particles in step (1) are usually attached with residual impurities or other impurities / stains, which will affect the catalytic performance of the catalyst prepared subsequently, especially the commercially available activated carbon particles. Based on this, it is necessary to pre-treat the activated carbon particles mainly including washing, and the pre-treating mainly including washing can be a pre-treating method known in the art, and those skilled in the art can perform specific operations according to conventional production processes or methods described in the prior art.

[0054] In one embodiment, in order to improve the pretreatment effect on the activated carbon particles, the step (1) mainly includes a washing pretreatment, specifically: the activated carbon particles are washed with ultrapure water and then dried, then washed with alkaline, and then washed with ultrapure water and dried to obtain the pretreated activated carbon.

[0055] In the above embodiment, under laboratory conditions, alkali washing can be further preferably performed by immersing in alkali solution. The alkali solution can be selected from alkali solutions selected for conventional alkali washing, such as sodium hydroxide solution and potassium hydroxide solution, and the mass concentration of the alkali solution is preferably 5-7%; the specific immersion time can be preferably 12-14 hours at room temperature and pressure.

[0056] It should be noted that the above technical solution mainly includes a washing pretreatment, the purpose of which is to remove residual impurities or other impurities / stains attached to the surface of the activated carbon particles. The above preferred pretreatment specific process steps are mainly carried out under laboratory conditions. In actual industrial production, the pretreatment method can be improved and replaced according to actual conditions and based on common knowledge.

[0057] In this article, the pretreated activated carbon in step (2) is immersed in an organic solution with a melamine mass concentration of 0.006 to 0.0167 g / ml for at least 24 hours, which is a conventional process for loading nitrogen source on activated carbon. In one embodiment, the amount of organic solution containing melamine is preferably 1 to 4 ml / g based on the mass of activated carbon.

[0058] In this article, the melamine mass concentration in step (2) is an organic solution of 0.006 to 0.0167 g / ml, wherein the solvent is a conventional organic solvent capable of dissolving melamine, such as any one of methanol, acetic acid, and dimethylformamide.

[0059] In one embodiment, the pretreated activated carbon in step (2) is immersed in an organic solution having a melamine concentration of 0.006 to 0.0167 g / ml for at least 24 hours, wherein the immersion treatment may be performed by standing, or by mechanical stirring, ultrasonic treatment or other conventional auxiliary process means to increase the efficiency of the immersion treatment. Those skilled in the art should know that the immersion treatment is a conventional process method, and those skilled in the art can select a suitable immersion treatment method according to actual needs and actual process conditions.

[0060] Herein, the copper salt in step (4) is selected from conventional copper source raw materials for supporting copper oxide catalysts, and in one embodiment, for example, any one of copper nitrate, copper acetate, copper sulfate, copper carbonate, and copper hydroxide. However, it should be noted that the specific solubility of the selected specific copper salt in water should be taken into account.

[0061] In one preferred embodiment, the copper salt in step (4) is copper nitrate.

[0062] In this article, the nitrogen-doped activated carbon described in step (4) is immersed in a copper salt solution with a mass percentage concentration of 8 to 12 wt% for 1.5 to 2.5 hours, which is a conventional process for loading metal salts on activated carbon. In one embodiment, the amount of copper salt solution used, based on the mass of the activated carbon, is preferably 1.5 to 2.5 ml / g.

[0063] In one embodiment, the nitrogen-doped activated carbon in step (4) is immersed in a copper salt solution with a mass percentage concentration of 8 to 12 wt% for 1.5 to 2.5 hours, wherein the impregnation treatment is preferably ultrasonic-assisted impregnation treatment, and the process parameters are preferably ultrasonic-assisted impregnation treatment with an ultrasonic frequency of 20 to 30 Hz and a temperature of 30 to 40°C.

[0064] In this article, the washing and drying are in accordance with the conventional principles of chemical processes, and those skilled in the art can perform specific operations according to common knowledge.

[0065] In the above embodiment, under laboratory conditions, washing is usually performed with ultrapure water for 3 times or more; drying is usually performed at 100-110° C. for at least 12 hours.

[0066] On the other hand, the present invention also provides a regeneration method for the above-mentioned CuO@nitrogen-doped carbon-based catalyst, which is to immerse the CuO@nitrogen-doped carbon-based catalyst in deionized water at a temperature of 35-55°C for 1-2 hours, and after drying, heat it to 200-300°C at a heating rate of 3-5°C / min in a dry air or pure oxygen atmosphere and keep it warm for 1.5-2.5 hours to obtain the regenerated CuO@nitrogen-doped carbon-based catalyst.

[0067] On the other hand, the CuO@ nitrogen-doped carbon-based catalyst provided by the present invention is used to remove PH from industrial tail gas. 3 , especially under anaerobic conditions, at pH 3 Gas concentration is 200~400mg / Nm 3 The catalytic reaction removes pH under the condition that the reaction temperature is at least 50°C. 3 .

[0068] The present invention will be further explained in detail with reference to the following examples. However, it should be understood by those skilled in the art that these examples are provided for illustrative purposes only and are not intended to limit the present invention.

[0069] Example

[0070] The embodiments of the present application will be described in detail below in conjunction with the examples, but it will be appreciated by those skilled in the art that the following examples are only used to illustrate the present application and should not be considered as limiting the scope of the present application. The specific conditions not specified in the examples are carried out according to the conditions recommended by normal conditions or manufacturers. The reagents used or the instruments not specified by the manufacturer are all conventional products that can be obtained commercially. The application should not be construed as being limited to the specific examples described.

[0071] 1. Raw materials

[0072] Material Name concentration Manufacturer <![CDATA[Cu(NO 3 ) 2 ·3H 2 O]]> 99.0％～102.0％ Chengdu Kelong Chemicals Co., Ltd. NaOH 96％ Shanghai Aladdin Biochemical Technology Co., Ltd. <![CDATA[Melamine (C 3 H 6 N 6 )]]> ≥99％ Shanghai Aladdin Biochemical Technology Co., Ltd. Dry air Chengdu Kelong Chemicals Co., Ltd. <![CDATA[N 2 ]]> ≥99.99％ Chengdu Xuyuan Chemical Co., Ltd. Ar ≥99.99％ Chengdu Xuyuan Chemical Co., Ltd. <![CDATA[PH 3 ]]> 500ppm Chongqing Ruixin Gas Co., Ltd.

[0073] Example 1

[0074] Embodiment 1 provides a kind of pH removal 3 The preparation method of the CuO@ nitrogen-doped carbon-based catalyst mainly comprises the following steps:

[0075] (1) Weigh 10.1959 g of activated carbon particles, wash them with ultrapure water for 5 times, and then dry them in an oven at 100°C for 12 h; weigh 7.0 g of NaOH, prepare 100 mL of NaOH solution, immerse the dried activated carbon in 20 mL of NaOH solution at room temperature and pressure for 12 h, then wash them with ultrapure water for 5 times, and then dry them in an oven at 100°C for 12 h, as the pretreated activated carbon for later use;

[0076] (2) Weighing 0.2107 g of melamine and dissolving it in 20 mL of methanol as a melamine methanol solution, immersing the pretreated activated carbon obtained in step (1) in the melamine methanol solution for 24 hours; after the time is up, drying in an oven at 100° C. for 12 hours to obtain melamine-loaded activated carbon;

[0077] (3) calcining the melamine-loaded activated carbon obtained in step (2) under an inert atmosphere (argon atmosphere, purity ≥ 99.999%), heating the mixture to 1000° C. at a heating rate of 10° C. / min and keeping the temperature for 2 h to prepare nitrogen-doped activated carbon;

[0078] (4) Weigh 12.9304 g of Cu(NO 3 ) 2 ·3H 2 O and ultrapure water are prepared into 100 mL of copper nitrate solution, and the nitrogen-doped activated carbon obtained in step (3) is immersed in 20 mL of copper nitrate solution for ultrasonic-assisted immersion treatment for 2 h, with an ultrasonic frequency of 20 Hz and a temperature of 30° C. After the time is up, the activated carbon is washed with ultrapure water for 6 times to remove the residual copper nitrate solution, and dried in an oven at 100° C. for 12 h to obtain nitrogen-doped activated carbon loaded with copper nitrate;

[0079] (5) The copper nitrate-loaded nitrogen-doped activated carbon obtained in step (4) is calcined under inert atmosphere conditions, heated to 500° C. at a heating rate of 5° C. / min and kept at this temperature for 2 h to prepare a CuO@nitrogen-doped carbon-based catalyst as a sample, denoted as Cu-N-AC.

[0080] 3.0076 g of the CuO@ nitrogen-doped carbon-based catalyst prepared in Example 1 was weighed and placed in a quartz reactor of φ15 mm×40 mm. The carrier gas used in the reaction was high-purity nitrogen (purity ≥99.999%). The reaction conditions were: PH 3 Concentration 201.80mg / Nm 3 , space velocity 3990mL / (h·g), reaction temperature 70℃. Figure 1 As shown in the figure, the efficiency of CuO@ nitrogen-doped carbon-based catalyst dropped to below 80% after 717h of reaction. 3 The adsorption capacity is 534.5 mg / g.

[0081] Example 2

[0082] Example 2 is a method for removing pH from the CuO@ nitrogen-doped carbon-based catalyst obtained in Example 1. 3 After testing, the efficiency of the inactivated samples dropped below 80% (such as Figure 2 As shown in the figure, the surface is bright silver after deactivation) for regeneration, the deactivated CuO@nitrogen-doped carbon-based catalyst is immersed in deionized water at 50°C for 1h, dried in an oven at 100°C for 12h, and then heated to 200°C at a heating rate of 5°C / min in a dry air atmosphere and calcined for 2h to obtain the regenerated CuO@nitrogen-doped carbon-based catalyst as a sample, recorded as Cu-N-AC-R.

[0083] like Figure 3As shown in the figure, after the deactivated CuO@ nitrogen-doped carbon-based catalyst was immersed in deionized water at 50°C for 1 hour, no obvious blue color was observed in the impregnation solution. At the same time, ion chromatography was used to analyze the PO 4 3- The concentration was tested to be 550.5 mg / g, which is consistent with the pH 3 The removal amount (534.5 mg / g) is similar, indicating that the pH of the catalyst removal 3 Can PO 4 3- Recycling.

[0084] 2.9561 g of the regenerated CuO@ nitrogen-doped carbon-based catalyst of Example 2 was weighed and placed in a quartz reactor of φ15 mm×40 mm. The carrier gas used in the reaction was high-purity nitrogen (purity ≥99.999%). The reaction conditions were: PH 3 Concentration 199.38mg / Nm 3 , space velocity 8119mL / (h·g), reaction temperature 70℃. Figure 4 As shown in the figure, the removal efficiency of the regenerated CuO@ nitrogen-doped carbon-based catalyst dropped to below 80% after 284 h. 3 The adsorption capacity of the regenerated catalyst was 432.8 mg / g. 3 The processing capacity can still reach 80.97% of the fresh catalyst (534.5 mg / g), indicating that the catalyst has good stability and regenerability, and the regeneration method is also feasible.

[0085] The test results show that CuO@ nitrogen-doped carbon-based catalyst has an effect on PH 3 The removal effect is obvious, and the regeneration effect after deactivation is still excellent, which has good application prospects. In addition, the catalyst preparation process is simple, the material shape requirements are low, the process is widely applicable, and the activated carbon-based carrier is cheap and easy to obtain, the overall economic cost is low, and it is suitable for PH in industrial waste gas. 3 Purification is a practical method.

[0086] Comparative Example 1

[0087] Comparative Example 1 is a comparative sample of a catalyst based on unloaded copper oxide, and its preparation method mainly includes the following steps:

[0088] (1) Weigh 10.0078 g of activated carbon particles, wash them with ultrapure water for 5 times, and then dry them in a 100°C oven for 12 h; weigh 7.0 g of NaOH, prepare 100 mL of NaOH solution, immerse the dried activated carbon in 20 mL of NaOH solution at room temperature and pressure for 12 h, then wash them with ultrapure water for 5 times, and then dry them in a 100°C oven for 12 h, as the pretreated activated carbon for later use;

[0089] (2) Weighing 0.2040 g of melamine and dissolving it in 20 mL of methanol as a melamine methanol solution, immersing the pretreated activated carbon obtained in step (1) in the melamine methanol solution for 24 hours; after the time is up, drying in an oven at 100° C. for 12 hours to obtain melamine-loaded activated carbon;

[0090] (3) The melamine-loaded activated carbon obtained in step (2) was calcined under an inert atmosphere (argon atmosphere, purity ≥ 99.999%), and the temperature was increased to 1000° C. at a heating rate of 10° C. / min and kept at that temperature for 2 h to prepare nitrogen-doped activated carbon as a comparative sample, which was recorded as N-AC.

[0091] Weigh 2.9830 g of the nitrogen-doped activated carbon prepared in Comparative Example 1 and place it in a quartz reactor of φ15 mm × 40 mm. The carrier gas used in the reaction is high-purity nitrogen (purity ≥ 99.999%). The reaction conditions are: PH 3 Concentration 196.79mg / Nm 3 , space velocity 4023mL / (h·g), reaction temperature 70℃. Figure 5 As shown, nitrogen-doped activated carbon has an effect on pH 3 The gas removal effect was poor, and the pH value was 3 The gas removal efficiency is reduced to below 80%, which has a negative impact on pH. 3 The adsorption capacity is only 9.3 mg / g.

[0092] Comparative Example 2

[0093] Comparative Example 2 is a comparative sample based on a non-nitrogen-doped supported copper oxide catalyst, and its preparation method mainly includes the following steps:

[0094] (1) Weigh 10.0536 g of activated carbon particles, wash them with ultrapure water for 5 times, and then dry them in a 100°C oven for 12 h; weigh 7.0 g of NaOH, prepare 100 mL of NaOH solution, immerse the dried activated carbon in 20 mL of NaOH solution at room temperature and pressure for 12 h, then wash them with ultrapure water for 5 times, and then dry them in a 100°C oven for 12 h, as the pretreated activated carbon for later use;

[0095] (2) Weigh 12.8714 g of Cu(NO 3 ) 2 ·3H 2O and ultrapure water are prepared into 100 mL of copper nitrate solution, and the nitrogen-doped activated carbon obtained in step (3) is immersed in 20 mL of copper nitrate solution for ultrasonic-assisted immersion treatment for 2 h, with an ultrasonic frequency of 20 Hz and a temperature of 30° C. After the time is up, the activated carbon is washed with ultrapure water for 6 times to remove the residual copper nitrate solution, and dried in an oven at 100° C. for 12 h to obtain activated carbon loaded with copper nitrate;

[0096] (3) The copper nitrate-loaded activated carbon obtained in step (2) was calcined under an inert atmosphere, heated to 500° C. at a heating rate of 5° C. / min and kept at that temperature for 2 h to prepare an activated carbon catalyst loaded with copper oxide as a comparative sample, which was recorded as Cu-AC.

[0097] 3.1340 g of the copper oxide-loaded activated carbon catalyst prepared in Comparative Example 2 was weighed and placed in a quartz reactor of φ15 mm×40 mm. The carrier gas used in the reaction was high-purity nitrogen (purity ≥99.999%). The reaction conditions were: PH 3 Concentration 198.36mg / Nm 3 , space velocity 3829mL / (h·g), reaction temperature 70℃. Figure 6 As shown in the figure, the efficiency of the copper oxide-loaded activated carbon catalyst dropped to below 80% 234 hours after the start of the reaction. 3 The adsorption capacity is 169.5 mg / g.

[0098] Comparative Example 3

[0099] Comparative Example 3 is a comparison of the copper oxide-loaded activated carbon catalyst obtained in Comparative Example 2 in the removal of pH 3 After testing, the efficiency of the inactivated control samples dropped to below 80% (such as Figure 7 The deactivated copper oxide-loaded activated carbon catalyst was regenerated by immersing it in deionized water at 50°C for 1 hour, drying it in an oven at 100°C for 12 hours, and then heating it to 200°C at a heating rate of 5°C / min in a dry air atmosphere for calcination for 2 hours to obtain a regenerated copper oxide-loaded activated carbon catalyst as a comparison sample, recorded as Cu-AC-R.

[0100] like Figure 3 As shown, after the deactivated copper oxide-loaded activated carbon catalyst was immersed in deionized water at 50°C for 1 hour, the immersion liquid was obviously blue, proving that its active components were dissolved.

[0101] Weigh 2.9064 g of the regenerated copper oxide-loaded activated carbon catalyst obtained in Comparative Example 3 and place it in a quartz reactor of φ15 mm×40 mm. The carrier gas used in the reaction is high-purity nitrogen (purity ≥99.999%). The reaction conditions are: PH 3 Concentration 201.01mg / Nm3 , space velocity 8258mL / (h·g), reaction temperature 70℃. Figure 8 As shown in Figure 2, the removal efficiency of the copper oxide-loaded activated carbon catalyst after regeneration dropped to below 80% after the first 6 hours. 3 The adsorption capacity is 7.1 mg / g, and the regeneration effect is not ideal.

[0102] Comparative Example 4

[0103] Comparative Example 4 is a method for preparing a sulfur-doped carbon-based dephosphorization reaction system for copper oxide loading in a prior invention patent application. 3 The embodiment 1 of the "catalyst and preparation method thereof (CN117427656A)" mainly comprises the following steps:

[0104] (1) After the activated carbon particles are pretreated mainly by washing, they are used as pretreated activated carbon for later use;

[0105] The pretreatment mainly includes washing, specifically: washing the activated carbon particles with ultrapure water and drying them, then immersing them in a sodium hydroxide solution with a mass concentration of 7% for 12 hours, and then washing them with ultrapure water and drying them to obtain pretreated activated carbon;

[0106] (2) using copper nitrate trihydrate to prepare a copper nitrate solution with a mass concentration of 15%;

[0107] The activated carbon pretreated in step (1) is immersed in a copper nitrate solution for ultrasonic immersion treatment for 2 hours, and the amount of the copper nitrate solution used is 4 ml / g based on the mass of the pretreated activated carbon; after the time is up, washing to remove the residual copper nitrate solution, and drying to obtain the activated carbon loaded with copper nitrate;

[0108] (3) mixing the copper nitrate-loaded activated carbon obtained in step (2) and elemental sulfur powder in a mass ratio of 1:0.52 to obtain a mixed material;

[0109] The mixed material is then calcined in a tube furnace in a high-purity argon atmosphere (purity ≥ 99.999%) to prepare a sulfur-doped carbon-based de-PH copper oxide-loaded 3 Catalyst, as a catalyst sample;

[0110] The calcination process is carried out in the following order:

[0111] ① After heating to 30℃, maintain this temperature for 30min;

[0112] ② Raise the temperature to 90℃ at a rate of 6℃ / min and maintain this temperature for 30min;

[0113] ③ Raise the temperature to 150°C at a rate of 3°C / min, and then raise the temperature to 200°C at a rate of 2°C / min;

[0114] ④ Raise the temperature to 500℃ at a rate of 5℃ / min, maintain this temperature for 120min and then cool down automatically.

[0115] Weigh 3.0827 g of the catalyst sample obtained in Comparative Example 4 and place it in The carrier gas used in the reaction was high-purity nitrogen (purity ≥ 99.999%), and the reaction conditions were: PH 3 Concentration 207.51mg / Nm 3 , airspeed 2260h -1 , reaction temperature 70℃. Figure 3 As shown, the catalyst samples had a significant effect on pH in the first 168 h. 3 The removal efficiency was basically stable at about 99%, and then began to fluctuate and decline until it dropped below 80% after 336 hours. 3 The removal amount is 260.32 mg / g.

[0116] The catalyst sample obtained in Comparative Example 4 was removed by 3 After the test, the deactivated samples whose efficiency dropped below 80% were regenerated by immersing them in deionized water at 50°C for 1 hour, drying them in an oven at 100°C for 12 hours, and then heating them to 200°C at a heating rate of 5°C / min in a dry air atmosphere and calcining them for 2 hours to obtain the regenerated catalyst samples.

[0117] After the catalyst sample regenerated in this comparative example was immersed in deionized water at 50° C. for 1 hour, the immersion liquid was obviously blue, indicating that the active components were dissolved.

[0118] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A method for preparing a CuO@ nitrogen-doped carbon-based catalyst for removing PH3, characterized in that The main steps include: (1) After the activated carbon particles are pretreated mainly by washing, they are used as pretreated activated carbon for later use; (2) immersing the pretreated activated carbon obtained in step (1) in an organic solution having a melamine concentration of 0.006 to 0.0167 g / ml for at least 24 hours; after the time is up, drying to obtain melamine-loaded activated carbon; (3) calcining the melamine-loaded activated carbon obtained in step (2) under inert atmosphere conditions, heating the temperature to 800-1000° C. at a heating rate of 9.5-10.5° C. / min and maintaining the temperature for 1.5-2.5 h to prepare nitrogen-doped activated carbon; (4) immersing the nitrogen-doped activated carbon obtained in step (3) in a copper salt solution having a mass percentage concentration of 8 to 12 wt% for 1.5 to 2.5 h; after the time is up, washing to remove the residual copper salt solution, and drying to obtain the copper salt-loaded nitrogen-doped activated carbon; (5) The copper salt-loaded nitrogen-doped activated carbon obtained in step (4) is calcined under inert atmosphere conditions, heated to 500-600° C. at a heating rate of 4.5-5.5° C. / min and kept at this temperature for 2-3 h to prepare a CuO@nitrogen-doped carbon-based catalyst.

2. The preparation method according to claim 1, characterized in that: The step (1) mainly includes a pretreatment of washing, specifically: washing the activated carbon particles with ultrapure water and then drying, then washing with alkali, and then washing with ultrapure water and drying to obtain the pretreated activated carbon.

3. The preparation method according to claim 2, characterized in that: The alkali washing is performed by immersing in alkali solution; wherein the alkali solution is sodium hydroxide solution or potassium hydroxide solution, and the mass concentration of the alkali solution is 5-7%; the immersion is specifically performed at room temperature and pressure for 12-14 hours.

4. The preparation method according to claim 1, characterized in that: The copper salt in step (4) is any one of copper nitrate, copper acetate, copper sulfate, copper carbonate and copper hydroxide.

5. The preparation method according to claim 1, characterized in that: The copper salt in step (4) is copper nitrate.

6. The preparation method according to claim 1, characterized in that: The nitrogen-doped activated carbon in step (4) is immersed in a copper salt solution with a mass percentage concentration of 8 to 12 wt% for 1.5 to 2.5 hours, wherein the immersion treatment is ultrasonic-assisted immersion treatment, and the process parameters are ultrasonic-assisted immersion treatment with an ultrasonic frequency of 20 to 30 Hz and a temperature of 30 to 40°C.

7. The CuO@nitrogen-doped carbon-based catalyst prepared by the method for preparing the CuO@nitrogen-doped carbon-based catalyst for removing PH3 as claimed in claim 1.

8. A method for regenerating the CuO@ nitrogen-doped carbon-based catalyst according to claim 7, characterized in that The CuO@nitrogen-doped carbon-based catalyst is immersed in deionized water at 35-55°C for 1-2 hours. After drying, the temperature is increased to 200-300°C at a heating rate of 3-5°C / min in a dry air or pure oxygen atmosphere and kept for 1.5-2.5 hours to obtain a regenerated CuO@nitrogen-doped carbon-based catalyst.

9. Use of the CuO@nitrogen-doped carbon-based catalyst as claimed in claim 7 in the field of removing PH3 gas.

10. The use according to claim 9, characterized in that: Under anaerobic conditions, at a PH3 gas concentration of 200-400 mg / Nm 3 The PH3 is removed by catalytic reaction under the condition that the reaction temperature is at least 50°C.

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