Chlorine-resistant mesoporous CoSnO x T-5 materials, methods of making and use

Abstract

The application discloses an anti-chlorine mesoporous CoSnO x / T-5 material, a preparation method and application, comprising the following steps: first, etching HZSM-5 by using tetrapropylammonium hydroxide to form a mesoporous material and as a carrier T-5; loading CoSn precursors on the carrier T-5; in air, converting the CoSn precursors into CoSn oxides by a calcination method to prepare a CoSnOx / T-5 material for catalytic combustion of 1,2-dichloroethane. x / HZSM-5, Co3O4 / T-5, SnO2 / T-5, CoSnO x The catalytic activity and anti-chlorine property of the CoSnO x / T-5 catalyst for catalytic combustion of 1,2-dichloroethane are greatly improved. Meanwhile, the CoSnO x / T-5 catalyst prepared by the application has good dispersity, the mesoporous structure promotes effective contact of 1,2-dichloroethane with the catalyst and accelerates adsorption of the reactants.

Description

Technical Field

[0001] This invention relates to the field of catalytic combustion support material preparation and catalytic combustion decomposition of VOCs, specifically to a chlorine-resistant mesoporous CoSnO material. x / T-5 Materials, Preparation Methods and Applications. Background Technology

[0002] With the development of modern industrial manufacturing, especially in the medical and chlor-alkali industries, the emission of chlorinated volatile organic compounds (CVOCs) has increased, causing serious environmental pollution and increasing risks to human health. To eliminate CVOC emissions from industrial processes, various efficient technologies have been developed. Among existing methods, catalytic combustion is one of the most effective due to its low reaction temperature and lack of secondary pollution.

[0003] The activity and structural stability of a catalyst are the main factors affecting the catalytic removal of CVOCs, determining the removal efficiency. Currently, catalysts mainly fall into two categories: noble metal catalysts and transition metal oxides. Noble metal catalysts exhibit the best catalytic activity, but their high cost and susceptibility to deactivation limit their application. Transition metal oxide catalysts have attracted widespread attention due to their low cost, high activity, thermal stability, and resistance to poisoning. The current challenge lies in achieving high activity and high structural stability at low temperatures without adding noble metals. Furthermore, the aggregation of active components on the catalyst surface is one of the reasons for low catalyst activity and poor stability. Therefore, preparing catalysts with dispersed active components and stable structures is crucial. Summary of the Invention

[0004] To address the above problems, this invention provides a chlorine-resistant mesoporous CoSnO x Materials, preparation methods and applications.

[0005] The present invention adopts the following technical solution:

[0006] A chlorine-resistant mesoporous CoSnO x The method for preparing the material includes the following steps:

[0007] Step 1: Dissolve tetrapropylammonium hydroxide in a solvent to obtain solution A;

[0008] Step 2: Disperse HZSM-5 in solution A, perform hydrothermal treatment, centrifuge and wash, and dry to obtain a solid;

[0009] Step 3: Calcine the solid obtained in Step 2 to obtain the T-5 carrier;

[0010] Step 4: Dissolve Co(NO3)2·6H2O and SnCl2·2H2O in a solvent and stir thoroughly to obtain solution B;

[0011] Step 5: Add the T-5 carrier described in Step 3 to solution B, heat in a water bath, centrifuge and wash, and dry to obtain CoSnO. x / T-5 precursor;

[0012] Step 6: Take the CoSnO obtained in Step 5 x The T-5 precursor was calcined to obtain CoSnO. x / T-5 materials.

[0013] Furthermore, in step 1, the volume ratio of tetrapropylammonium hydroxide to solvent is 1-5:25-30.

[0014] Furthermore, in step 2, the concentration of HZSM-5 dispersed in solution A is 0.2 g / ml, the hydrothermal temperature is 120–180 °C, and the time is 12–24 h.

[0015] Furthermore, in step 2, the washing conditions are as follows: the detergent is a mixture of water and ethanol, the drying time is 6-12 hours, and the drying temperature is 60-120°C.

[0016] Furthermore, in step 3, the calcination conditions are 400–600℃ for 3–6 hours.

[0017] Furthermore, in step 4, the mass ratio of Co(NO3)2·6H2O to SnCl2·2H2O is 0.3–1:0.005–0.01, and the stirring time is 2–8 hours.

[0018] Furthermore, in step 5, the mass ratio of T-5 carrier: Co(NO3)2·6H2O: SnCl2·2H2O is 0.5–5:0.3–1:0.005–0.01, the water bath temperature is 50–70℃, and the water bath time is 4–12 h; the washing conditions are a mixture of water and ethanol, the drying time is 6–12 h, and the temperature is 60–120℃.

[0019] Furthermore, in step 6, the calcination conditions are 400–600℃ for 3–6 hours.

[0020] Another aspect of the present invention provides a CoSnO x / T-5 materials.

[0021] Another aspect of the present invention provides CoSnO x Application of / T-5 material in catalysts.

[0022] The beneficial effects of this invention are:

[0023] The high-chlorine-resistant CoSnOx / T-5 catalyst prepared by this invention possesses a suitable mesoporous structure, which is beneficial for enhancing the adsorption and activation of reactants. The CoSnOx / T-5 with the mesoporous structure exhibits the best catalytic activity, achieving a 90% conversion rate of 1,2-dichloroethane at 200℃. This is significantly higher than that of CoSnOx / T-5 without tetrapropylammonium hydroxide treatment of the support. x The catalysts / HZSM-5 and Co3O4 / T-5 and SnO2 / T-5 supported on a single transition metal show significantly improved catalytic activity and chlorine resistance in the combustion of 1,2-dichloroethane. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments will be briefly described below. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention.

[0025] Figure 1 The pore size distribution diagrams are for HZSM-5, T-5, Example 1, and Comparative Examples 1 to 3.

[0026] Figure 2 The images shown are XRD patterns of Example 1 and Comparative Examples 1 to 3.

[0027] Figure 3 The diagram shows the catalytic activity of 1,2-dichloroethane during combustion in Example 1 and Comparative Examples 1-3.

[0028] Figure 4 The thermal stability diagrams for the catalytic combustion of 1,2-dichloroethane in Example 1 and Comparative Examples 1-3 are shown. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0030] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0031] Example 1

[0032] Dissolve 0.5 g of HZSM-5 in a mixture of 5 ml tetrapropylammonium hydroxide and 25 ml deionized water, hydrothermally at 150 °C for 24 h, wash with a mixture of water and ethanol, dry at 80 °C for 8 h, and calcine the resulting product at 450 °C for 3 h. The resulting product is denoted as T-5. Mix 0.5 g of T-5 with 0.3 g of cobalt nitrate and 0.005 g of stannous chloride in 30 ml of deionized water, stir at 70 °C for 6 h, dry at 100 °C for 8 h, and calcine the resulting product at 450 °C for 3 h. The resulting product is denoted as CoSnO. x / T-5.

[0033] Example 2

[0034] Dissolve 0.5 g of HZSM-5 in a mixture of 5 ml tetrapropylammonium hydroxide and 25 ml deionized water, hydrothermally at 120 °C for 12 h, wash with a mixture of water and ethanol, dry at 60 °C for 6 h, and calcine the resulting product at 400 °C for 6 h. The product is denoted as T-5. Mix 0.5 g of T-5 with 0.4 g of cobalt nitrate and 0.008 g of stannous chloride in 30 ml of deionized water, stir at 50 °C for 2 h, dry at 60 °C for 6 h, and calcine the resulting product at 400 °C for 6 h. The product is denoted as CoSnO. x / T-5.

[0035] Example 3

[0036] Dissolve 0.5 g of HZSM-5 in a mixture of 5 ml tetrapropylammonium hydroxide and 25 ml deionized water, hydrothermally at 180 °C for 12 h, wash with a mixture of water and ethanol, dry at 120 °C for 12 h, and calcine the resulting product at 600 °C for 6 h. The resulting product is denoted as T-5. Mix 0.5 g of T-5 with 0.5 g of cobalt nitrate and 0.01 g of stannous chloride in 30 ml of deionized water, stir at 70 °C for 8 h, dry at 120 °C for 12 h, and calcine the resulting product at 400 °C for 6 h. The resulting product is denoted as CoSnO. x / T-5.

[0037] Comparative Example 1

[0038] 0.5 g of HZSM-5, 0.25 g of cobalt nitrate, and 0.005 g of stannous chloride were mixed in 30 ml of deionized water, stirred at 70 °C for 6 h, dried at 100 °C for 8 h, and the resulting product was calcined at 450 °C for 3 h. The product was denoted as CoSnO. x / HZSM-5.

[0039] Comparative Example 2

[0040] Dissolve 0.5 g of HZSM-5 in a mixture of 5 ml tetrapropylammonium hydroxide and 25 ml deionized water, hydrothermally at 150 °C for 24 h, wash with a mixture of water and ethanol, dry at 80 °C for 8 h, and calcine the resulting product at 450 °C for 3 h. The product is denoted as T-5. Mix 0.5 g of T-5 with 0.25 g of cobalt nitrate in 30 ml of deionized water, stir at 70 °C for 6 h, dry at 100 °C for 8 h, and calcine the resulting product at 450 °C for 3 h. The product is denoted as Co3O4 / T-5.

[0041] Comparative Example 3

[0042] Dissolve 0.5 g of HZSM-5 in a mixture of 5 ml tetrapropylammonium hydroxide and 25 ml deionized water, hydrothermally at 150 °C for 24 h, wash with a mixture of water and ethanol, dry at 80 °C for 8 h, and calcine the resulting product at 450 °C for 3 h. The product is denoted as T-5. Mix 0.5 g of T-5 with 0.01 g of stannous chloride in 30 ml of deionized water, stir at 70 °C for 6 h, dry at 100 °C for 8 h, and calcine the resulting product at 450 °C for 3 h. The product is denoted as SnO2 / T-5.

[0043] Application examples

[0044] The high chlorine resistance CoSnO prepared in Example 1 x / T-5 catalyst, and CoSnO obtained in Comparative Example 1 x The catalysts HZSM-5, Co3O4 / T-5 obtained in Comparative Example 2, and SnO2 / T-5 obtained in Comparative Example 3 were used to evaluate the catalytic combustion activity of 1,2-dichloroethane. The specific operating steps are as follows:

[0045] Activity assays were performed in a fixed-bed continuous flow microreactor. 400 mg of catalyst (40–60 mesh) was mixed with 400 mg of quartz sand (40–60 mesh) and placed in a quartz tube with an inner diameter of 10 mm. 1000 ppm of 1,2-dichloroethane mixed with dry air was introduced into the microreactor, where it reacted with the catalyst in an electrically heated reactor. The reactor temperature range was 100 °C–290 °C, and the gas hourly space velocity (GHSV) was 15000 h⁻¹. -1 The gas produced after the reaction is introduced into the detection system.

[0046] The detection system was performed by gas chromatography (GC), specifically a GC-7900 model from Shanghai Tianmei Chemical Co., Ltd., equipped with an automatic sampling device. The concentration of 1,2-dichloroethane before and after the reaction was determined using the GC's FID flame ionization detector. A 50m × 0.32mm (ID) × 1.0μm TM-1 capillary column was used. The concentration of 1,2-dichloroethane was calculated from the detected peak area. A standard curve for 1,2-dichloroethane concentration was established using the external standard method in chromatographic quantitative analysis to calculate the actual concentration of 1,2-dichloroethane.

[0047] The catalytic oxidation activity of a catalyst is mainly represented by the conversion rate of 1,2-dichloroethane during combustion, and its calculation formula is as follows:

[0048]

[0049] In the formula, x represents the conversion rate of 1,2-dichloroethane, and C in and C out These represent the inlet and outlet concentrations of 1,2-dichloroethane before and after the reaction, respectively, in ppm.

[0050] The catalytic combustion activity diagrams of 1,2-dichloroethane in Examples 1 and 3 (see Figure 1) are as follows. Figure 2 It can be seen that CoSnO with its mesoporous structure exhibits high chlorine resistance. x / T-5 exhibits the best catalytic activity, achieving a 90% conversion rate of 1,2-dichloroethane at 200℃.

[0051] Figure 1 The diagram shows the pore size distribution of HZSM-5, T-5, Example 1, and Comparative Examples 1-3. HZSM-5 and Comparative Example 1 exhibit microporous structures, while T-5, Example 1, and Comparative Examples 2-3 have pore sizes between 2 and 50 nm, which are clearly mesoporous structures.

[0052] Figure 2 The XRD patterns of Examples 1 and Comparative Examples 1-3 are shown. The XRD results of Examples 1 and Comparative Examples 1-3 all contain characteristic peaks of HZSM-5, indicating the crystallinity and structural integrity of HZSM-5. The XRD results of Examples 1 and Comparative Examples 1-2 all contain characteristic peaks of Co3O4, while the XRD result of Comparative Example 3 contains characteristic peaks of SnO2, proving that Co3O4 and SnO2 are successfully loaded on the support. No Sn-related crystalline phases were found in Examples 1 and Comparative Examples 1-2, indicating that Sn is highly dispersed on the support surface, which is beneficial to improving catalytic activity.

[0053] Figure 4The figures show the stability test results of catalytic combustion of 1,2-dichloroethane in Examples 1 and Comparative Examples 1-3. As can be seen from the figures, after prolonged testing, the stability of Comparative Examples 1-3 decreased by 39% within the measured time, indicating that neither using a mesoporous support nor supporting a single oxide catalyst can improve the catalyst's resistance to chlorine poisoning. Example 1 showed virtually no loss of activity, indicating that this method has a positive effect on improving the catalyst's resistance to chlorine poisoning.

[0054] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for preparing a chloride-resistant mesoporous CoSnOx / T-5 material, characterized in that, Includes the following steps: Step 1: Dissolve tetrapropylammonium hydroxide in a solvent to obtain solution A; Step 2: Disperse the molecular sieve HZSM-5 with a silicon-to-aluminum ratio of 80 into solution A, perform hydrothermal treatment, centrifuge and wash, and dry to obtain a solid; Step 3: Calcine the solid obtained in Step 2 to obtain the T-5 carrier; Step 4: Dissolve Co(NO3)2·6H2O and SnCl2·2H2O in a solvent and stir thoroughly to obtain solution B; Step 5: Add the T-5 carrier described in Step 3 to solution B, heat in a water bath, centrifuge and wash, and dry to obtain the CoSnOx / T-5 precursor; Step 6: Calcine the CoSnOx / T-5 precursor obtained in Step 5 to obtain CoSnOx / T-5 material.

2. The method for preparing a chloride-resistant mesoporous CoSnOx / T-5 material according to claim 1, characterized in that, In step 1, the volume ratio of tetrapropylammonium hydroxide to solvent is 1-5:25-30.

3. The method for preparing a chloride-resistant mesoporous CoSnOx / T-5 material according to claim 1, characterized in that, In step 2, the concentration of HZSM-5 dispersed in solution A is 0.2 g / ml, the hydrothermal temperature is 120–180 °C, and the time is 12–24 h.

4. The preparation method of the chloride-resistant mesoporous CoSnOx / T-5 material according to claim 1, characterized in that, In step 2, the washing conditions are as follows: the detergent is a mixture of water and ethanol, the drying time is 6-12 hours, and the drying temperature is 60-120°C.

5. The method for preparing a chloride-resistant mesoporous CoSnOx / T-5 material according to claim 1, characterized in that, In step 3, the calcination conditions are 400–600℃ for 3–6 hours.

6. The method for preparing a chloride-resistant mesoporous CoSnOx / T-5 material according to claim 1, characterized in that, In step 4, the stirring time is 2 to 8 hours.

7. The method for preparing a chloride-resistant mesoporous CoSnOx / T-5 material according to claim 1, characterized in that, In step 5, the mass ratio of T-5 carrier: Co(NO3)2·6H2O: SnCl2·2H2O is 0.5~5:0.3~1:0.005~0.01, the water bath temperature is 50~70℃, and the water bath time is 4~12h; the washing conditions are a mixture of water and ethanol, the drying time is 6~12h, and the temperature is 60~120℃.

8. The method for preparing a chloride-resistant mesoporous CoSnOx / T-5 material according to claim 1, characterized in that, In step 6, the calcination conditions are 400–600℃ for 3–6 hours.

9. A CoSnOx / T-5 material is prepared by any one of the methods described in claims 1 to 8.

10. The CoSnOx / T-5 material as described in claim 9 in catalytic combustion 1,2 Applications in dichloroethane.

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