Ammonia gas detection method

Abstract

The invention discloses an ammonia gas detection method. According to the ammonia gas detection method, an MXene doped polyaniline material is adopted for detection. According to the method, polyaniline is grown on an MXene lamellar structure through in-situ polymerization, so that the MXene-doped polyaniline can be obtained. The MXene has excellent heat and electricity conduction, performance and stability. The ammonia gas sensor based on MXene doped polyaniline has the advantages of high sensitivity, high selectivity, strong repeatability and good stability, the power consumption of the sensor in the use process is greatly reduced, the use portability of the sensor is improved, and the ammonia gas sensor has important practice and research values in the technical field.

Description

Technical Field

[0001] The present application relates to an ammonia detection method, and belongs to the technical field of nanomaterial preparation. Background Art

[0002] With the continuous development of productivity and the improvement of quality of life, people's demands for production and life are getting higher and higher, which has promoted the increase in demand for toxic gas sensors. The research and development of gas sensors, especially the research on harmful gas sensors, has developed extremely rapidly. Ammonia is a toxic and pungent gas pollutant, which is commonly found in solvents, catalysts and raw materials in industrial production. At present, gas sensors for detecting ammonia have been widely used in production and life. Commonly used metal oxide materials (such as zinc oxide, tin oxide, cobalt oxide, etc.), but the detection temperature is relatively high and cannot be used in daily life. How to improve the sensitivity of ammonia detectors and reduce the detection temperature is the key to the research of ammonia gas sensors. Summary of the invention

[0003] According to one aspect of the present application, a method for detecting ammonia is provided, wherein the method uses MXene-doped polyaniline material for detection; the MXene is accordion-shaped or layered.

[0004] Optionally, the particle size of the MXene-doped polyaniline material is 100-500 meshes.

[0005] Optionally, the particle size of the MXene-doped polyaniline material is selected from any value of 100 mesh, 200 mesh, 300 mesh, 400 mesh, 500 mesh, or a range between any two of the above.

[0006] Optionally, the preparation method of the MXene-doped polyaniline material comprises:

[0007] A mixture containing MXene powder, an acid solution, an aniline monomer, and an oxidant is reacted and dried to obtain the MXene-doped polyaniline material.

[0008] Optionally, the dosage of the MXene powder, acid solution, aniline monomer, and oxidant is: 0.01-10 g: 20-100 mL: 10-500 μL: 5-200 mL.

[0009] Optionally, the acid solution is selected from at least one of hydrochloric acid, sulfuric acid and nitric acid.

[0010] Optionally, the concentration of the acid solution is 0.1-10 g / L.

[0011] Optionally, the concentration of the acid solution is selected from any value of 0.1 g / L, 0.5 g / L, 1 g / L, 2 g / L, 5 g / L, 8 g / L, 10 g / L or a range between any two of the above.

[0012] Optionally, the oxidant is selected from at least one of perchlorate, persulfate, periodate and dichromate.

[0013] Optionally, the perchlorate is selected from at least one of ammonium perchlorate, sodium perchlorate and potassium perchlorate.

[0014] Optionally, the persulfate is selected from at least one of ammonium persulfate, sodium persulfate and potassium persulfate.

[0015] Optionally, the periodate is selected from at least one of ammonium periodate, sodium periodate and potassium periodate.

[0016] Optionally, the dichromate is selected from at least one of ammonium dichromate, sodium dichromate and potassium dichromate.

[0017] Optionally, the concentration of the oxidant is 0.5-100 g / L.

[0018] Optionally, the concentration of the oxidant is selected from any value among 0.5 g / L, 2 g / L, 10 g / L, 20 g / L, 30 g / L, 50 g / L, 80 g / L, 100 g / L or a range between any two of the above.

[0019] Optionally, the reaction temperature is 0 to 20° C., and the reaction time is 2 to 50 hours.

[0020] Optionally, the drying temperature is 30-100°C.

[0021] This application is implemented using the following technical solutions:

[0022] A preparation method of MXene-doped polyaniline that can be used for ammonia detection comprises the following steps: dispersing a certain amount of MXene powder into water, adding aniline monomer, stirring evenly, adding an oxidant solution, reacting at 0-20° C. for a period of time, washing, drying, and crushing into 100-500 mesh powder.

[0023] The beneficial effects of this application include:

[0024] 1) The MXene-doped polyaniline process provided in this application is simple, has good stability, and is suitable for mass production.

[0025] 2) The MXene-doped polyaniline provided in this application exhibits a good and stable response to ammonia.

[0026] 3) The present application can obtain MXene-doped polyaniline by growing polyaniline on a MXene sheet structure through in-situ polymerization. MXene itself has excellent thermal and electrical conductivity, performance and stability. The ammonia sensor based on MXene-doped polyaniline of the present invention has the advantages of simple preparation and high sensitivity, greatly reduces the power consumption during the use of the sensor, and improves the portability of the sensor, which has important practical and research value in the field of this technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a 1 μm SEM characterization image of the MXene-doped polyaniline fiber in Example 1 of the present application.

[0028] Figure 2 This is the sensing curve of MXene-doped polyaniline fiber in Example 3 of the present application. DETAILED DESCRIPTION

[0029] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0030] Unless otherwise specified, the raw materials in the examples of this application were purchased through commercial channels.

[0031] In the examples of the present application, a field emission electron microscope (FESEM, FEI Nova Nano SEM 450) was used to perform SEM morphology characterization of MXene-doped polyaniline.

[0032] Example 1

[0033] Weigh 0.05g of accordion-shaped 200-mesh MXene powder and disperse it in 20mL of 1g / L hydrochloric acid solution. Add 500μL of aniline monomer. Then add 40mL of 50g / L ammonium persulfate solution, react at 2℃ for 10h, wash with water, dry at 80℃, and grind into 200-mesh powder to obtain MXene-doped polyaniline material.

[0034] Example 2

[0035] Weigh 0.1g of accordion-shaped 400-mesh MXene powder and disperse it in 25mL of 2g / L hydrochloric acid solution. Add 800μL of aniline monomer. Then add 80mL of 100g / L ammonium persulfate solution, react at 4℃ for 24h, wash with water, dry at 65℃, and grind into 500-mesh powder to obtain MXene-doped polyaniline material. Figure 1 As can be seen in the figure, polyaniline is successfully grown on MXene.

[0036] Example 3

[0037] Sensor test of ammonia concentration: Weigh 10 mg of the MXene-doped polyaniline solid sample prepared in Example 2 into a 5 mL centrifuge tube, add 0.8 mL of anhydrous ethanol, and ultrasonicate for 20 minutes. Use a pipette to take 10 μL of the dispersion, evenly apply it on the ceramic tube, and blow it dry with a 150°C hot air blower. Connect the prepared sensor to the multimeter and fix it in a 20L closed cavity. Each time, use a microinjection needle to take a certain amount of ammonia and inject it into the electric heating block in the closed cavity. The heating power of the external power supply of the electric heating block is 15W. Heat at 150°C for 1 minute, so that the final ammonia concentration in the cavity is 2 ppm. After turning off the heating power, count 10 minutes as the response time, and record the resistance change R of the multimeter. g After the reaction is finished, open the lid of the chamber to allow the sensor to come into contact with fresh air, and the resistance will rise again. Record the resistance back to its original value R a The above process was repeated at 2ppm, 5ppm, 10ppm, 20ppm and 40ppm ammonia concentrations. The resistance data collected was exported through the multimeter program to obtain the change value of the resistance signal over time. The time was used as the horizontal axis and the final change value of the resistance signal was compared with the initial value (ΔR / R0) as the vertical axis. Figure 2 As shown, from Figure 2 It can be seen that ammonia shows a sensitive response in the range of 2-40ppm.

[0038] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for detecting ammonia, characterized in that: The ammonia detection method uses MXene-doped polyaniline material for detection; MXene is accordion-shaped or layered.

2. The ammonia detection method according to claim 1, characterized in that: The particle size of the MXene-doped polyaniline material is 100-500 meshes.

3. The ammonia detection method according to claim 1, characterized in that: The preparation method of the MXene-doped polyaniline material comprises: A mixture containing MXene powder, an acid solution, an aniline monomer, and an oxidant is reacted and dried to obtain the MXene-doped polyaniline material.

4. The ammonia detection method according to claim 3, characterized in that: The dosage of the MXene powder, acid solution, aniline monomer, and oxidant is: 0.01~10g: 20~100mL: 10~500μL: 5~200mL.

5. The ammonia detection method according to claim 3, characterized in that: The acid solution is selected from at least one of hydrochloric acid, sulfuric acid and nitric acid.

6. The ammonia detection method according to claim 3, characterized in that: The concentration of the acid solution is 0.1-10 g / L.

7. The ammonia detection method according to claim 3, characterized in that: The oxidant is selected from at least one of perchlorate, persulfate, periodate and dichromate; Preferably, the perchlorate is selected from at least one of ammonium perchlorate, sodium perchlorate and potassium perchlorate; Preferably, the persulfate is selected from at least one of ammonium persulfate, sodium persulfate and potassium persulfate; Preferably, the periodate is selected from at least one of ammonium periodate, sodium periodate and potassium periodate; Preferably, the dichromate is selected from at least one of ammonium dichromate, sodium dichromate and potassium dichromate.

8. The ammonia detection method according to claim 3, characterized in that: The concentration of the oxidant is 0.5-100 g / L.

9. The ammonia detection method according to claim 3, characterized in that: The reaction temperature is 0-20°C, and the reaction time is 2-50h.

10. The ammonia detection method according to claim 3, characterized in that: The drying temperature is 30-100°C.

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