FeCoMnO x Catalyst, method of preparation and synergistic application in denitration and toluene removal

Abstract

The application discloses FeCoMnO x Catalyst, preparation method and synergistic application in denitration and toluene removal, relate to the technical field of catalysts, FeCoMnO x The preparation method of the catalyst is as follows: S1: dissolving a cobalt salt and a manganese salt in deionized water, adding ammonia water, carrying out reaction after ultrasonic treatment, and carrying out washing and drying on the product after reaction to obtain CoMn-LDH; S2: dispersing CoMn-LDH and sodium formate in ethanol-deionized water under the action of ultrasonic waves, then adding an iron salt and terephthalic acid in sequence to carry out reaction, and carrying out washing and drying on the product after reaction to obtain CoMn-LDH@Fe-MOF; and S3: carrying out calcination on CoMn-LDH@Fe-MOF under an inert atmosphere to obtain FeCoMnO x Catalyst. The catalyst has excellent removal rates of NO and toluene, has excellent water resistance and sulfur resistance, has low production cost and simple operation, and has a good application prospect.

Description

Technical Field

[0001] This invention relates to the field of catalyst technology, and more particularly to FeCoMnO x Catalysts, preparation methods, and synergistic applications in denitration and toluene. Background Technology

[0003] Currently, catalysts used in the removal of NO and toluene are diverse. Fe, Mn, and Co are abundant, inexpensive, and exhibit good catalytic activity, thus enabling the synergistic treatment of pollutants. However, developing catalysts for the simultaneous removal of NO and toluene at low temperatures remains a significant challenge. Summary of the Invention

[0004] Based on the technical problems existing in the background technology, this invention proposes FeCoMnO x Catalyst, preparation method, and synergistic application in denitrification and toluene removal: This catalyst exhibits excellent NO and toluene removal rates, as well as superior water and sulfur resistance. Furthermore, it boasts low production costs, simple operation, and promising application prospects.

[0005] This invention proposes a FeCoMnO x The preparation method of the catalyst is as follows:

[0006] S1: Dissolve cobalt salt and manganese salt in deionized water, add ammonia, sonicate and react. The product after reaction is washed and dried to obtain CoMn-LDH.

[0007] S2: CoMn-LDH and sodium formate were dispersed in ethanol-deionized water under ultrasonication, and then iron salt and terephthalic acid were added sequentially to react. After the reaction was completed, the product was washed and dried to obtain CoMn-LDH@Fe-MOF.

[0008] S3: Calcination of CoMn-LDH@Fe-MOF under an inert atmosphere yields FeCoMnO x catalyst.

[0009] Preferably, the cobalt salt is one or more of cobalt nitrate hexahydrate, cobalt sulfate hexahydrate, cobalt carbonate hexahydrate, and cobalt chloride hexahydrate; the manganese salt is one or more of manganese nitrate hexahydrate, manganese sulfate hexahydrate, manganese carbonate hexahydrate, and manganese chloride hexahydrate; and the iron salt is one or more of ferric nitrate hexahydrate, ferric sulfate hexahydrate, ferric carbonate hexahydrate, and ferric chloride hexahydrate.

[0010] Preferably, the molar ratio of ammonia water to metal salt is (0.9-1.1):1.

[0011] Preferably, the molar ratio of cobalt salt, manganese salt, iron salt and terephthalic acid is (0.9-1.1):(0.9-1.1):(0.9-1.1):0.5.

[0012] Preferably, the conditions for ultrasound in S1 are: ultrasound power 120 W~600 W, ultrasound time 0.5-2 h.

[0013] Preferably, the reaction conditions in S1 are: temperature 100-180 ℃, time 8-12 h.

[0014] Preferably, the conditions for ultrasound in S2 are: ultrasound power 120W~600W, ultrasound time 1-3 h.

[0015] Preferably, the reaction conditions in S2 are: 100-180 °C for 8-12 h.

[0016] Preferably, the calcination conditions in S3 are: temperature 350-450 ℃, time 1-2 h.

[0017] This invention proposes a FeCoMnO x The catalyst was prepared using the method described above.

[0018] The FeCoMnO proposed in this invention as described above x Application of catalysts in the removal of nitrogen oxides and / or toluene.

[0019] Beneficial technical effects of the present invention:

[0020] (1) The FeCoMnO of the present invention is used x The catalyst preparation method enables uniform dispersion of CoMn-LDH cores and promotes the nucleation sites of Fe-MOF on the LDH surface, forming a perfect core-shell structure and increasing the specific surface area of ​​the catalyst.

[0021] (2) The present invention uses an LDH / MOF template and calcines it in a protective gas atmosphere to obtain the target catalyst. During the calcination process, the synergistic decomposition of MOF and LDH not only removes the organic framework and avoids particle agglomeration, but also retains abundant hierarchical channels and generates a large number of oxygen vacancies, thereby improving catalytic activity; at the same time, it also forms a hollow structure inside the catalyst, which is conducive to the entry of harmful gases into its interior, thereby improving contact efficiency and reaction rate.

[0022] (3) FeCoMnO prepared by the present invention x The catalyst exhibits excellent performance in low-temperature, high-efficiency denitrification and toluene conversion. It demonstrates 100% NO conversion within the range of 150-350 °C and over 95% toluene conversion within the range of 200-350 °C.

[0023] (4) The FeCoMnOx catalyst prepared by this invention has excellent water and sulfur resistance and stability, which is beneficial to practical industrial applications.

[0024] (5) The raw materials of the present invention are inexpensive, which reduces production costs and is conducive to large-scale industrial production and application. Attached Figure Description

[0025] Figure 1 These are TEM images proposed in this invention; where (a) is the α-Fe₂O₃ catalyst of Comparative Example 1, and (b) is the CoMnO₃ catalyst of Comparative Example 2. x Catalyst, (c) is FeCoMnO from Example 1 x Catalyst; (d) is FeCoMnO from Comparative Example 3 x catalyst;

[0026] Figure 2 XRD patterns of the catalysts prepared in Example 1 and Comparative Examples 1-3;

[0027] Figure 3 The above are BET diagrams proposed in this invention; where (a) is the adsorption isotherm diagram of the catalysts prepared in Example 1 and Comparative Examples 1-3, and (b) is the pore size distribution diagram of the catalysts prepared in Example 1 and Comparative Examples 1-3.

[0028] Figure 4 The above are H2-TPR diagrams of the catalysts prepared in Example 1 and Comparative Examples 1-3 of this invention.

[0029] Figure 5 The NH3-TPD diagrams are shown for the catalysts prepared in Example 1 and Comparative Examples 1-3 of this invention.

[0030] Figure 6 The diagram shows a comparison of the catalytic activity of the catalysts prepared in Example 1 and Comparative Examples 1-3 of this invention; where (a) represents the NO removal rate and (b) represents the toluene conversion rate.

[0031] Figure 7 The catalyst proposed in this invention exhibits catalytic activity stability under different conditions; wherein (a) is the catalyst of Comparative Example 1, and (b) is the catalyst of Example 1. Detailed Implementation

[0032] The present invention will be further explained below with reference to specific embodiments.

[0033] Example 1

[0034] 1.164 g of cobalt nitrate hexahydrate and 0.806 g of manganese nitrate hexahydrate were dissolved in 40 mL of deionized water, and 0.5 mL of ammonia water was added and stirred until homogeneous. The mixture was then sonicated for 1 h, and the solution was poured into a reaction vessel and reacted at 110 °C for 9 h. After the reaction, the mixture was washed and dried for later use to obtain CoMn-LDH.

[0035] CoMn-LDH and 0.0020 g sodium formate were dissolved in 40 mL of ethanol-deionized water. Then, 1.1352 g ferric nitrate hexahydrate and 0.2326 g terephthalic acid were added sequentially, and the mixture was stirred for 20 min and sonicated for 2 h. The solution was then transferred to a high-pressure reactor and maintained at 120 °C for 10 h. After washing and drying, CoMn-LDH@Fe-MOF was obtained.

[0036] The catalyst obtained by calcining CoMn-LDH@Fe-MOF in a tube furnace at 400 °C for 1 h at a heating rate of 5 °C / min is designated as FeMnCoO. x catalyst.

[0037] Tested in flue gas containing 500 ppm NO, 50 ppm toluene, 5% H2O and 50 ppm SO2 within a temperature range of 150-350 ℃.

[0038] Example 2

[0039] In this embodiment, the calcination temperature of CoMn-LDH@Fe-MOF in the test method is 350℃, and all other conditions are the same as in Example 1.

[0040] Example 3

[0041] In this embodiment, the mass of cobalt nitrate hexahydrate is 0.817 g, the mass of manganese nitrate hexahydrate is 0.806 g, and all other conditions are the same as in Example 1.

[0042] Comparative Example 1

[0043] 0.672 g of ferric nitrate hexahydrate and 0.320 g of terephthalic acid were dissolved in 40 mL of deionized water and stirred for 20 min. The mixture was sonicated for 2 h, aged at room temperature for 24 h, washed, and dried to obtain the Fe-MOF precursor.

[0044] The Fe-MOF precursor was calcined in a tube furnace at 400 °C for 1 h at a heating rate of 5 °C / min. The resulting catalyst was designated as α-Fe₂O₃ catalyst.

[0045] Tested in flue gas containing 500 ppm NO, 50 ppm toluene, 5% H2O and 50 ppm SO2 within a temperature range of 150-350 ℃.

[0046] Comparative Example 2

[0047] 1.164 g of cobalt nitrate hexahydrate and 0.806 g of manganese nitrate hexahydrate were dissolved in 40 mL of deionized water, and 0.5 mL of ammonia water was added. The mixture was stirred until homogeneous. The solution was sonicated for 1 h, then poured into a reaction vessel and reacted at 110 °C for 9 h. After washing and drying, the CoMn-LDH precursor was obtained.

[0048] The CoMn-LDH precursor was calcined in a muffle furnace at 400 °C for 1 h at a heating rate of 5 °C / min. The resulting catalyst was designated as CoMnO. x catalyst.

[0049] Comparative Example 3

[0050] 1.164 g of cobalt nitrate hexahydrate and 0.806 g of manganese nitrate hexahydrate were dissolved in 40 mL of deionized water, and 0.5 mL of ammonia water was added. The mixture was stirred until homogeneous. The solution was poured into a reaction vessel and reacted at 110 °C for 9 h. After washing and drying, the CoMn-LDH precursor was obtained.

[0051] CoMn-LDH and 0.0020 g sodium formate were dissolved in 40 mL of ethanol-deionized water, followed by the addition of 0.0558 g ferric nitrate hexahydrate and 0.320 g terephthalic acid. The mixture was stirred for 20 min. The solution was then transferred to a high-pressure reactor and maintained at 120 °C for 10 h. After washing and drying, CoMn-LDH@Fe-MOF was obtained.

[0052] The CoMn-LDH@Fe-MOF precursor was calcined in a muffle furnace at 400 °C for 1 h at a heating rate of 5 °C / min. The resulting catalyst was designated FeCoMnO. x catalyst.

[0053] Tested in flue gas containing 500 ppm NO, 50 ppm toluene, 5% H2O and 50 ppm SO2 within a temperature range of 150-350 ℃.

[0054] Figure 1 The different catalysts exhibited distinct morphologies. The α-Fe₂O₃ catalyst in Comparative Example 1 appeared as nanorods, while the CoMnO₂ catalyst in Comparative Example 2... x The catalyst exhibits a nanosheet structure, as shown in Comparative Example 3, FeCoMnO x The catalyst lacked a regular morphology; the FeCoMnO in Example 1... x The catalyst exhibits a hollow structure, which may be the fundamental reason for its superior catalytic performance by optimizing the exposure of active sites and mass transfer efficiency.

[0055] Figure 2 XRD patterns of the catalysts are shown. The characteristic diffraction peaks of the α-Fe₂O₃ catalyst in Comparative Example 1 correspond to α-Fe₂O₃. These diffraction peaks are strong and narrow, indicating good crystallinity and grain size of the sample. FeCoMnO₃ from Example 1... x Comparative Example 2 CoMnO x And Comparative Example 3 FeCoMnO x All catalysts correspond to MnCo₂O₄ spinel. Doping with Mn and Co alters the crystal structure. Example 1: FeCoMnO x The catalyst has a stable crystal structure that is not easily altered, and can maintain high activity for a long time.

[0056] BET of catalysts, such as Figure 3 As shown. FeCoMnO in Example 1 x α-Fe₂O₃ (Comparative Example 1) and CoMnO₃ (Comparative Example 2) x And Comparative Example 3 FeCoMnO x The specific surface area is 73.435 m². 2 ·g -1 23.173 m 2 ·g -1 62.970 m 2 ·g -1 and 59.091 m 2 ·g -1 The hollow structure increases the specific surface area of ​​Example 1, thereby improving the adsorption of pollutants.

[0057] Figure 4 Each curve in the H2-TPR curve shows multiple reduction peaks, and the main reduction process involves Fe. 3+ →Fe 2+ → Fe 0 Co 3+ → Co 2+ and Mn 4+ → Mn 3+ The transformation is related to this. The FeMnCoOx in Example 1 exhibited multiple reduction peaks at < 400 °C, indicating its excellent low-temperature oxidation activity.

[0058] Figure 5 Each curve in the NH3-TPD curve showed a desorption peak. The desorption peak of FeMnCoOx in Example 1 shifted towards the higher temperature range, below 200 °C, and still belonged to a weak Lewis acid site. Meanwhile, the FeMnCoOx in Example 1... xThe peak intensity of the desorption peak is higher than that of α-Fe₂O₃ in Comparative Example 1 and CoMnO₂ in Comparative Example 2. x And Comparative Example 3 FeCoMnO x That is, the total acidity of FeMnCoO in Example 1 x maximum.

[0059] Depend on Figure 6 The NO conversion rate and toluene conversion rate show that the FeCoMnO prepared in Example 1... x The catalyst exhibits excellent NO and toluene conversion rates, demonstrating 100% NO conversion within the range of 150-350 °C and over 95% toluene conversion within the range of 200-350 °C.

[0060] Figure 7 The α-Fe₂O₃ of Comparative Example 1 and the FeMnCoO₃ of Example 1 were compared. x The catalyst's NO conversion rate and stability under the introduction of H2O, SO2, and toluene were evaluated. Example 1: FeMnCoO x Its performance is superior to that of α-Fe2O3 in Comparative Example 1.

[0061] Although embodiments of this application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application. The scope of this application is defined by the appended claims and their equivalents, all of which should be included within the protection scope of this application.

Claims

1. A FeCoMnO x A method for preparing a catalyst, characterized in that, The steps are as follows: S1: Dissolve cobalt salt and manganese salt in deionized water, add ammonia, sonicate and react. After washing and drying, the product is obtained as CoMn-LDH. S2: CoMn-LDH and sodium formate were dispersed in ethanol-deionized water under ultrasonication, and then iron salt and terephthalic acid were added in sequence to react. After the reaction was completed, the product was washed and dried to obtain CoMn-LDH@Fe-MOF. S3: Calcination of CoMn-LDH@Fe-MOF under an inert atmosphere yields FeCoMnO x catalyst.

2. The FeCoMnO according to claim 1 x A method for preparing a catalyst, characterized in that, The cobalt salt is one or more of cobalt nitrate hexahydrate, cobalt sulfate hexahydrate, cobalt carbonate hexahydrate, and cobalt chloride hexahydrate; the manganese salt is one or more of manganese nitrate hexahydrate, manganese sulfate hexahydrate, manganese carbonate hexahydrate, and manganese chloride hexahydrate; the iron salt is one or more of ferric nitrate hexahydrate, ferric sulfate hexahydrate, ferric carbonate hexahydrate, and ferric chloride hexahydrate.

3. The FeCoMnO according to claim 1 x A method for preparing a catalyst, characterized in that, The molar ratio of ammonia water to metal salt is (0.9-1.1):1; the molar ratio of cobalt salt, manganese salt, iron salt and terephthalic acid is (0.9-1.1):(0.9-1.1):(0.9-1.1):0.

5.

4. The FeCoMnO according to claim 1 x A method for preparing a catalyst, characterized in that, The conditions for ultrasound in S1 are: ultrasound power 120 W~600 W, ultrasound time 0.5-2 h.

5. The FeCoMnO according to claim 1 x A method for preparing a catalyst, characterized in that, The reaction conditions in S1 are: temperature 100-180 ℃, time 8-12 h.

6. The FeCoMnO according to claim 1 x A method for preparing a catalyst, characterized in that, The conditions for ultrasound in S2 are: ultrasound power 120W~600W, ultrasound time 1-3 h.

7. The FeCoMnO according to claim 1 x A method for preparing a catalyst, characterized in that, The reaction conditions in S2 are: 100-180 °C for 8-12 h.

8. The FeCoMnO according to claim 1 x A method for preparing a catalyst, characterized in that, The calcination conditions for S3 are: temperature 350-450 ℃, time 1-2 h.

9. A FeCoMnO x Catalyst, characterized in that, It is prepared by the preparation method according to any one of claims 1-8.

10. The FeCoMnO as described in claim 9 x Application of catalysts in the removal of nitrogen oxides and / or toluene.

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