A method for treating contaminated air using light-plasma coupling

Abstract

The present application relates to a kind of method for treating polluted air using light-plasma coupling, belong to environmental treatment technical field, first preparation alpha-pinene composite rGO / CeO2 Nanoparticles, by filling alpha-pinene composite rGO / CeO2 Nanoparticles into the catalyst chamber of the inner wall of plasma reactor uniformly, adjust the voltage and current of plasma reactor, generate plasma zone, for treating polluted air.The present application has beneficial effect: the radiation of excitation light source generated by plasma treatment, drive photocatalytic reaction speed to accelerate, nitrogen oxides occur photocatalytic reaction, the OH and H2O reaction of alpha-pinene composite rGO / CeO2 catalyst surface in photocatalytic process generates hydroxyl radical, hydroxyl radical will reach the effect of reaction pure with nitrogen oxides, alpha-pinene contains special bicyclo double bond structure, aromatic ring on rGO and the carbon-carbon double bond of alpha-pinene occur π-π stacking, distance reduces, to improve charge transport performance, improve the removal effect of alpha-pinene composite rGO / CeO2 catalyst to nitrogen oxides.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of environmental treatment, and particularly relates to a method for treating polluted air by using light-plasma coupling. BACKGROUND

[0002] With the development of economy and the progress of the times, people's requirements for air quality are getting higher and higher. With the development of modern industry and the increasing number of automobiles, air pollution has become a serious global problem. Nitrogen oxides, as one of the main air pollutants, will cause photochemical smog, acid rain, ozone layer depletion and other environmental problems affecting human sustainable development. The exhaust gas of fixed sources such as combustion devices of factories is one of the main sources of nitrogen oxides in the atmosphere.

[0003] De-nitration technology is mainly divided into wet and dry methods. The main process for removing NOx in industrial devices is to use selective non-catalytic reduction technology SNCR and selective catalytic reduction technology SCR. SNCR and SCR technology mainly selectively reduces NOx to H2O and N2 without or with catalyst. These methods are time-consuming and have complex technical processes. Therefore, there is an urgent need to develop a new method for treating polluted air. SUMMARY

[0004] The purpose of the present application is to provide a method for treating polluted air by using light-plasma coupling. First, alpha-pinene composite rGO / CeO2 nanoparticles are prepared. The alpha-pinene composite rGO / CeO2 nanoparticles are uniformly filled into the catalyst chamber of the inner wall of the plasma reactor. The voltage and current of the plasma reactor are adjusted to generate a plasma belt for treating polluted air, thereby improving the removal rate of nitrogen oxides.

[0005] The technical problem to be solved by the present application is that the traditional method for treating polluted air has poor performance.

[0006] The purpose of the present application can be achieved by the following technical solutions:

[0007] A method for treating polluted air by using light-plasma coupling, comprising the following steps:

[0008] (1) Dissolve GO in methanol and peel off for 30 minutes by using a probe ultrasonic instrument. Add CeO2 under vigorous stirring, stir, mix 25% mass fraction of ammonia solution into the above solution to increase the pH value to 11, then pour the mixture into a 100mL Teflon container, load it into a stainless steel autoclave, and perform hydrothermal reaction in a vacuum furnace. Then, take the autoclave out of the vacuum furnace, let it cool naturally, wash the mixture with ultra-light water for 5 times, and dry it in a vacuum oven at 90℃ to obtain rGO / CeO2 nanocomposite material;

[0009] (2) rGO / CeO2 nanocomposite is dispersed in deionized water, ultrasonic, to obtain a dispersion liquid, alpha-pinene is added to the dispersion liquid and stirred, ultrasonic treatment is carried out to disperse the alpha-pinene uniformly, ultrasonic, centrifugal, and drying to obtain alpha-pinene composite rGO / CeO2 nanoparticles;

[0010] (3) The alpha-pinene composite rGO / CeO2 nanoparticles are uniformly filled into the catalyst chamber of the inner wall of the plasma reactor, the voltage and current of the plasma reactor are adjusted, the plasma belt is generated, the nitrogen oxide polluted air is introduced, and the treated waste gas is collected;

[0011] (4) The treated waste gas is passed through the plasma reactor again, the waste gas after secondary treatment is collected, and the air treated by light-plasma coupling is obtained.

[0012] Further, the amount of GO, methanol and CeO2 in step (1) is 0.05-0.06g: 25-26mL: 0.05-0.06g.

[0013] Further, the stirring time in step (1) is 2-2.5 hours, the hydrothermal reaction temperature is 180-200 DEG C, and the hydrothermal reaction time is 8-18 hours.

[0014] Further, the ultrasonic time in step (2) is 20-30 min, and the drying temperature is 60-70 DEG C.

[0015] Further, in step (3), the voltage and current of the plasma reactor are adjusted, a transient 6-30KHz high frequency voltage is generated by a pulse high voltage power supply, and the discharge current is gradually increased from 0.1A to 120A.

[0016] The beneficial effects of the application are:

[0017] (1) In the technical scheme of the application, rGO has a large specific surface area and rich pore structure, which becomes the basis for good adsorption of nitrogen oxides by alpha-pinene composite rGO / CeO2, rGO and CeO2 play a synergistic catalytic role in nitrogen oxides under light irradiation, alpha-pinene contains a special double ring double bond structure, the aromatic ring on rGO and the carbon-carbon double bond of alpha-pinene occur π-π stacking to promote the adsorption and catalysis of nitrogen oxides. Alpha-pinene composite rGO / CeO2 has a high conjugated system, and the distance is reduced due to π-π stacking, thereby improving the charge transport performance and improving the removal effect of alpha-pinene composite rGO / CeO2 catalyst on nitrogen oxides.

[0018] (2) In the technical scheme of the present application, the α-pinene composite rGO / CeO2 nanoparticles are uniformly filled into the catalyst chamber of the inner wall of the plasma reactor, the voltage and current of the plasma reactor are adjusted to generate a plasma zone, and under the radiation of the excitation light source, the plasma-driven photocatalytic reaction speed of the α-pinene composite rGO / CeO2 is accelerated, the photocatalytic reaction occurs on the nitrogen oxide polluted air, and the OH and H2O on the surface of the α-pinene composite rGO / CeO2 catalyst react to generate hydroxyl radicals during the photocatalytic process, and the hydroxyl radicals can react with nitrogen oxides to achieve pure reaction.

[0019] (3) In the technical scheme of the present application, only the α-pinene composite rGO / CeO2 photocatalytic reaction, it is difficult to handle high concentration, large flow of harmful gas, the energy utilization rate is not high, and after the plasma effect, this defect can be made up. Single plasma coupling will decompose carbon dioxide to produce adverse intermediate by-products, resulting in unstable plasma reaction. Therefore, the photocatalyst is coupled with the plasma reaction, and the photocatalyst can better inhibit the generation of by-products. Gas discharge produces low-temperature plasma, produces ultraviolet rays, excites α-pinene composite rGO / CeO2 to promote photocatalytic degradation of nitrogen oxides, and is beneficial to energy utilization rate. The α-pinene composite rGO / CeO2 plays a certain dielectric role, which can enhance the local electric field. The strong electric field in the plasma reaction area can inhibit the electron and hole recombination of the α-pinene composite rGO / CeO2 to a certain extent, and improve the quantum efficiency of photocatalysis. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of the present application.

[0021] Embodiment 1

[0022] A method for treating polluted air by using light-plasma coupling, comprising the following steps:

[0023] The mass ratio of GO, methanol and CeO2 is 0.05g:25mL:0.05g.

[0024] (1) GO was dissolved in methanol and exfoliated by using a probe sonicator for 30 minutes, CeO2 was added under vigorous stirring and stirred for 2 hours, 25% mass fraction of ammonia solution was mixed into the above solution to increase the pH value to 11, then the mixture was poured into a 100 mL Teflon container, a stainless steel autoclave was loaded, and a hydrothermal reaction was carried out at 180°C in a vacuum furnace for 8 hours, then the autoclave was taken out of the vacuum furnace, and after natural cooling, the mixture was washed with ultra-light water for 5 times, and dried in a vacuum oven at 90°C, to obtain rGO / CeO2 nanocomposite;

[0025] (2) The rGO / CeO2 nanocomposite was dispersed in deionized water and ultrasonicated for 20 min to obtain a dispersion liquid, α-pinene was added to the dispersion liquid and stirred, and ultrasonicated for 20 min to uniformly disperse the α-pinene, and then centrifuged and dried at 60°C to obtain α-pinene composite rGO / CeO2 nanoparticles;

[0026] (3) The α-pinene composite rGO / CeO2 nanoparticles were uniformly filled into the catalyst chamber on the inner wall of the plasma reactor, the voltage and current of the plasma reactor were adjusted, a transient 6KHz high frequency voltage was generated by a pulse high voltage power supply, and at the same time the discharge current was gradually increased from 0.1A to 120A, a plasma belt was generated, and nitrogen oxide contaminated air was introduced, and the treated exhaust gas was collected;

[0027] (4) The treated exhaust gas was passed through the plasma reactor again, and the exhaust gas after secondary treatment was collected to obtain air treated by light-plasma coupling.

[0028] Example 2

[0029] A method for treating polluted air by light-plasma coupling, comprising the following steps:

[0030] The mass ratio of GO, methanol and CeO2 is 0.052g:25.2mL:0.052g.

[0031] (1) GO was dissolved in methanol and exfoliated by using a probe sonicator for 30 minutes, CeO2 was added under vigorous stirring and stirred for 2.1 hours, 25% mass fraction of ammonia solution was mixed into the above solution to increase the pH value to 11, then the mixture was poured into a 100 mL Teflon container, a stainless steel autoclave was loaded, and a hydrothermal reaction was carried out at 185°C in a vacuum furnace for 9 hours, then the autoclave was taken out of the vacuum furnace, and after natural cooling, the mixture was washed with ultra-light water for 5 times, and dried in a vacuum oven at 90°C, to obtain rGO / CeO2 nanocomposite;

[0032] (2) The rGO / CeO2 nanocomposite material is dispersed in deionized water and ultrasonic treatment is performed for 22 min to obtain a dispersion liquid. Alpha-pinene is added to the dispersion liquid and stirred. Ultrasonic treatment is performed to uniformly disperse the alpha-pinene. Ultrasonic treatment is performed for 22 min. Centrifugation is performed. Drying is performed at 62°C to obtain alpha-pinene composite rGO / CeO2 nanoparticles;

[0033] (3) The alpha-pinene composite rGO / CeO2 nanoparticles are uniformly filled into a catalyst chamber on the inner wall of the plasma reactor. The voltage and current of the plasma reactor are adjusted. A transient 8KHz high-frequency voltage is generated by a pulse high-voltage power supply. At the same time, the discharge current is gradually increased from 0.1A to 120A. A plasma belt is generated. Nitrogen oxide-polluted air is introduced. The treated exhaust gas is collected.

[0034] (4) The treated exhaust gas is passed through the plasma reactor again. The exhaust gas after secondary treatment is collected to obtain air treated by light-plasma coupling.

[0035] Example 3

[0036] A method for treating polluted air by light-plasma coupling, comprising the following steps:

[0037] The mass ratio of GO, methanol, and CeO2 is 0.055g:25.5mL:0.055g.

[0038] (1) GO is dissolved in methanol and stripped by using a probe ultrasonic instrument for 30 minutes. CeO2 is added under vigorous stirring. Stirring is performed for 2.1 hours. A 25% mass fraction of ammonia solution is mixed into the above solution to increase the pH value to 11. Then, the mixture is poured into a 100mL Teflon container. A stainless steel autoclave is loaded. Hydrothermal reaction is performed at 190°C in a vacuum furnace for 11 hours. Then, the autoclave is taken out of the vacuum furnace and naturally cooled. The mixture is washed with ultra-light water for 5 times. Drying is performed in a vacuum oven at 90°C. rGO / CeO2 nanocomposite material is obtained.

[0039] (2) The rGO / CeO2 nanocomposite material is dispersed in deionized water and ultrasonic treatment is performed for 22 min to obtain a dispersion liquid. Alpha-pinene is added to the dispersion liquid and stirred. Ultrasonic treatment is performed to uniformly disperse the alpha-pinene. Ultrasonic treatment is performed for 22 min. Centrifugation is performed. Drying is performed at 62°C to obtain alpha-pinene composite rGO / CeO2 nanoparticles;

[0040] (3) The α-pinene / rGO / CeO2 nanoparticles are uniformly filled into the catalyst chamber on the inner wall of the plasma reactor. The voltage and current of the plasma reactor are adjusted. A transient 20 KHz high-frequency voltage is generated by a pulse high-voltage power supply, and at the same time, the discharge current is gradually increased from 0.1 A to 120 A. A plasma zone is generated, and the nitrogen oxide contaminated air is introduced. The treated exhaust gas is collected.

[0041] (4) The treated exhaust gas is passed through the plasma reactor again, and the exhaust gas after secondary treatment is collected to obtain the air treated by the light-plasma coupling.

[0042] Example 4

[0043] A method for treating polluted air by light-plasma coupling, comprising the following steps:

[0044] The mass ratio of GO, methanol, and CeO2 is 0.06g: 26mL: 0.06g.

[0045] (1) GO is dissolved in methanol and stripped by using a probe ultrasonic instrument for 30 minutes. CeO2 is added under vigorous stirring for 2.5 hours. A 25% mass fraction of ammonia solution is mixed into the above solution to increase the pH value to 11. Then the mixture is poured into a 100mL Teflon container, loaded into a stainless steel autoclave, and subjected to hydrothermal reaction at 200°C in a vacuum furnace for 18 hours. Then, the autoclave is taken out of the vacuum furnace and allowed to cool naturally. The mixture is washed with ultra-light water for 5 times and dried in a vacuum oven at 90°C to obtain an rGO / CeO2 nanocomposite;

[0046] (2) The rGO / CeO2 nanocomposite is dispersed in deionized water and ultrasonicated for 30 min to obtain a dispersion liquid. α-pinene is added to the dispersion liquid and stirred. Ultrasonic treatment is performed to uniformly disperse the α-pinene. After ultrasonic treatment for 30 min, centrifugation and drying at 70°C, α-pinene / rGO / CeO2 nanoparticles are obtained.

[0047] (3) The α-pinene / rGO / CeO2 nanoparticles are uniformly filled into the catalyst chamber on the inner wall of the plasma reactor. The voltage and current of the plasma reactor are adjusted. A transient 20 KHz high-frequency voltage is generated by a pulse high-voltage power supply, and at the same time, the discharge current is gradually increased from 0.1 A to 120 A. A plasma zone is generated, and the nitrogen oxide contaminated air is introduced. The treated exhaust gas is collected.

[0048] (4) The treated exhaust gas is passed through the plasma reactor again, and the exhaust gas after secondary treatment is collected to obtain the air treated by the light-plasma coupling.

[0049] Comparative Example 1

[0050] A method for treating polluted air using a catalyst, comprising the following steps:

[0051] The mass ratio of GO, methanol and CeO2 is 0.05g:25mL:0.05g.

[0052] (1) Dissolve GO in methanol and peel off for 30 minutes by using a probe ultrasonic instrument, add CeO2 under vigorous stirring and stir for 2 hours, mix 25% mass fraction of ammonia solution into the above solution to increase the pH value to 11, then pour the mixture into a 100mL Teflon container, load it into a stainless steel autoclave, and carry out hydrothermal reaction at 180℃ in a vacuum furnace for 8 hours, then take the autoclave out of the vacuum furnace, let it cool naturally, wash the mixture with ultra-light water for 5 times, and dry it in a vacuum oven at 90℃ to obtain rGO / CeO2 nanocomposite;

[0053] (2) Disperse the rGO / CeO2 nanocomposite in deionized water, ultrasonic for 20min to obtain a dispersion liquid, add α-pinene into the dispersion liquid and stir, ultrasonic treatment to disperse α-pinene uniformly, ultrasonic for 20min, centrifugal, and dry at 60℃ to obtain α-pinene composite rGO / CeO2 nanoparticles;

[0054] (3) Uniformly fill the catalyst chamber of the inner wall of the reactor with α-pinene composite rGO / CeO2 nanoparticles, and introduce air polluted by nitrogen oxides, collect the treated exhaust gas;

[0055] (4) Pass the treated exhaust gas through the catalyst chamber again, collect the exhaust gas after secondary treatment, and obtain air treated by the catalyst under natural light.

[0056] Comparative Example 2

[0057] A method for treating polluted air using plasma, comprising the following steps:

[0058] (1) Adjust the voltage and current of the plasma reactor, generate a high-frequency voltage of 6KHz by a pulse high-voltage power supply, and gradually increase the discharge current from 0.1A to 120A, generate a plasma belt, and introduce air polluted by nitrogen oxides, collect the treated exhaust gas;

[0059] (2) Pass the treated exhaust gas through the plasma reactor again, collect the exhaust gas after secondary treatment, and obtain air treated by the plasma.

[0060] Statistical Examples 1-4, compare the treated nitrogen oxide gas collected in Examples 1-2, respectively, determine the content of nitrogen oxides therein by gas chromatograph, compare the content of nitrogen oxides before entering the plasma reactor, calculate the removal rate of nitrogen oxides, as shown in Table 1:

[0061] Table 1

[0062]

[0063] From the above Table 1, it can be seen that the method for treating polluted air by using light-plasma coupling in the embodiment of the present application has a higher removal rate than Comparative Examples 1-2. Because Comparative Example 1 only has a catalyst to treat the polluted air containing nitrogen oxides under the action of natural light, and Comparative Example 2 only has a plasma to radiate nitrogen oxides in the polluted air, the removal rate of nitrogen oxides is low.

[0064] In the description of the specification, the description of the terms "one embodiment", "an example", "a specific example" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0065] The above is only an example and description of the present application, and those skilled in the art can make various modifications or supplements or use similar ways to replace the described specific embodiments, as long as they do not deviate from the invention or exceed the scope defined by the present claims, which should belong to the protection scope of the present application.

Claims

1. A method for treating polluted air using photo-plasma coupling, characterized in that: Includes the following steps: (1) Dissolve GO in methanol and exfoliate it for 30 minutes using a probe ultrasonic instrument. Add CeO2 under vigorous stirring and stir. Mix 25% mass fraction ammonia solution into the above solution to increase the pH value to 11. Then pour the mixture into a 100 mL Teflon container, put it into a stainless steel autoclave, and carry out hydrothermal reaction in a vacuum furnace at 200 °C. Then, remove the autoclave from the vacuum furnace and let it cool naturally. Wash the mixture 5 times with ultralight water and dry it in a vacuum oven at 90 °C to obtain rGO / CeO2 nanocomposite material. (2) Disperse the rGO / CeO2 nanocomposite material in deionized water, sonicate to obtain a dispersion, add α-pinene to the dispersion and stir, sonicate to make the α-pinene disperse evenly, centrifuge, and dry to obtain α-pinene composite rGO / CeO2 nanoparticles. (3) α-pinene composite rGO / CeO2 nanoparticles are uniformly filled into the catalyst chamber of the inner wall of the plasma reactor, the voltage and current of the plasma reactor are adjusted to generate a plasma band, and air polluted by nitrogen oxides is introduced at the same time to collect the treated waste gas. (4) The treated waste gas is passed through the plasma reactor again, and the waste gas after secondary treatment is collected to obtain air treated by photo-plasma coupling; In step (1), the ratio of GO, methanol, and CeO2 used is 0.05-0.06g: 25-26mL: 0.05-0.06g; The stirring time in step (1) is 2-2.5 hours; The hydrothermal reaction time in step (1) is 8-18 hours.

2. The method for treating polluted air using photo-plasma coupling according to claim 1, characterized in that: The drying temperature in step (2) is 60-70℃.

3. The method for treating polluted air using photo-plasma coupling according to claim 1, characterized in that: In step (3), the voltage and current of the plasma reactor are adjusted by generating a high-frequency voltage of 6-30KHz instantaneously through a pulsed high-voltage power supply, while the discharge current gradually increases from 0.1A to 120A.

Images