Method for deep degradation of large-flow mixed organic exhaust gas

Abstract

The application discloses a method for deep degradation of large-flow mixed organic waste gas, comprising the following steps: a) preparing ferroferric oxide / stannous sulfide composite microspheres; b) performing surface modification on carbon nanotubes by using a mixed solution of nitric acid and perchloric acid; c) performing surface modification on the carbon nanotubes after acid treatment by using a ferric chloride solution; d) mixing hydrogen peroxide, the ferroferric oxide / stannous sulfide composite microspheres and the surface-modified carbon nanotubes to obtain a suspension; e) adding the suspension into a circulating bubble-spraying-mist removal integrated device to form a multifunctional layered bubble liquid in a bubble zone thereof; f) pumping the upper liquid in the bubble liquid as spraying liquid for a spraying backflow zone; and g) discharging the waste gas after being treated by the bubble-spraying process and then absorbed by a mist removal backflow zone. The method has stable treatment efficiency on organic waste gas, can realize recycling of reaction suspension, and obviously improves the deep purification efficiency on industrial waste gas.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of waste gas treatment, and particularly relates to a method for deep degradation of mixed organic waste gas with large flow rate. BACKGROUND

[0002] As a main component of industrial waste gas, organic waste gas has a great influence on the atmospheric environment and human health. Common sources of organic waste gas pollution include chemical industry parks, coking industries, furniture manufacturing industries, landfills, and breeding farms. The emission of organic waste gas from these sources is characterized by large air volume, low concentration, and complex composition, and it is still challenging to achieve deep degradation of the organic waste gas by using existing technologies.

[0003] In the treatment of organic waste gas, Fenton oxidation is one of the most efficient methods. However, due to the characteristics of common organic waste gas emissions, the main difficulty in using Fenton method for treatment is the deep degradation of the refractory and insoluble components in the mixed organic waste gas. The limiting factor for the deep degradation of refractory components is the generation efficiency of hydroxyl radicals, i.e., the catalytic ability of the catalyst; and the limiting factor for the deep degradation of insoluble components is the extremely low gas-liquid mass transfer efficiency. Therefore, specifically improving the catalytic oxidation efficiency and gas-liquid mass transfer efficiency of the Fenton system is the key to solving the problem of deep degradation of mixed organic waste gas with large flow rate. In actual production, the combination of processes and the use of combined devices can improve the efficiency of waste gas purification to some extent. However, the existing methods have the problems of instability, inability to meet the production requirements, lack of targeted improvement of the two processes of catalysis and mass transfer, and cannot meet the needs of industrial production for deep degradation of mixed organic waste gas with large flow rate. SUMMARY

[0004] The purpose of the present application is to overcome the shortcomings of the prior art and provide a method for deep degradation of mixed organic waste gas with large flow rate.

[0005] The method is based on the Fenton system and is designed to optimize the bubble-spray- reflux integrated device and the bubble-spray liquid to achieve efficient and deep degradation of organic waste gas, taking into account the characteristics of large air volume, low concentration, and complex composition of industrial waste gas. The method has stable treatment efficiency for organic waste gas, can realize the recycling of reaction suspension liquid, and is suitable for deep degradation of industrial waste gas, thus significantly improving the efficiency of waste gas purification.

[0006] The present application comprises the following steps:

[0007] a) preparing magnetite particles by using a hydrothermal method, dispersing the prepared magnetite particles in deionized water to obtain a suspension, and adding stannous chloride solution and sodium sulfide solution into the magnetite suspension in sequence to obtain magnetite / stannous sulfide composite microspheres;

[0008] b) surface modification of carbon nanotubes with a mixed solution of nitric acid and perchloric acid;

[0009] c) immersing the carbon nanotubes treated with acid into a saturated ferric chloride solution to react, centrifuging, washing and freeze-drying after the reaction to form catalytic active sites on the surface of the carbon nanotubes;

[0010] d) mixing hydrogen peroxide, the ferric oxide / stannous sulfide composite microspheres and the carbon nanotubes treated with acid and ferric chloride solution to obtain a suspension;

[0011] d) adding the suspension into a circulating bubble-spray-mist integrated device to form a multi-layered reaction liquid with different functions in the lower bubble zone of the integrated device for removing different components of the high-flow organic waste gas;

[0012] e) pumping the upper solution in the lower bubble zone as the spraying liquid of the middle spray reflux zone of the integrated device;

[0013] f) introducing the high-flow mixed organic waste gas into the above-mentioned integrated device, and the organic waste gas first undergoes mass transfer, adsorption and catalytic oxidation in the lower bubble zone, then enters the middle spray reflux zone for reflux, the gas treated by the above-mentioned bubble-spray process is absorbed by the silk screen mist removal device in the upper mist removal reflux zone, and the mist condenses and then refluxes to the lower bubble zone for secondary treatment, and the treated waste gas is discharged through the gas outlet.

[0014] In the above-mentioned steps, the multi-layered suspension formed in the lower bubble zone includes: the lower layer is mainly the suspension of composite nanoparticles, which is a high-efficiency Fenton catalytic oxidation system; the middle layer is the mixed suspension of composite nanoparticles and carbon nanotubes, which is a synergistic system of mass transfer and catalysis; and the upper layer is mainly the suspension of carbon nanotubes, which can improve the mass transfer efficiency of the insoluble waste gas, and the insoluble substances are adsorbed on the surface of the modified carbon nanotubes and quickly undergo catalytic oxidation reaction. The depth of the bubble zone is positively correlated with the degradation efficiency of the organic waste gas.

[0015] The spraying process mainly focuses on the removal of insoluble waste gas, therefore, the upper solution in the lower bubble zone is pumped as the spraying liquid, so that the waste gas not removed by the lower bubble zone is further removed in the middle spray reflux zone and then refluxed to the bubble zone for deep degradation.

[0016] Preferably, in the step a), 1 g of ferric oxide particles is dispersed in 180-250 mL of deionized water;

[0017] Preferably, in the step a), the volume of the stannous chloride solution is 8-30 mL, and the molar concentration is 1.33×10 -5 -0.11 mol·L -1 The volume of the sodium sulfide solution is 8-30 mL, and the molar concentration is 1.33×10-5 ~0.11 mol·L -1 .

[0018] Preferably, in the step a), the particle size of the Fe3O4 / SnS2 composite microspheres is 90-120 nm, and the mass percentage of SnS2 is 4-35%. The loading of SnS2 can improve the catalyst activity of Fenton reaction, increase the yield of hydroxyl radicals, and further improve the catalytic oxidation capacity.

[0019] Preferably, in the step b), for every 1 g of carbon nanotubes, 20-40 mL of nitric acid solution is added, and the concentration of the used nitric acid solution is 0.15-0.25 mol / L; 5-15 mL of perchloric acid solution is added, and the concentration of the used perchloric acid solution is 0.05-0.12 mol / L; after adding the mixed acid, an oil bath is used for constant temperature heating and refluxing at 120℃ for 2-4 h.

[0020] Preferably, in the step c), every 1 g of the acid-treated carbon nanotubes is immersed in 8-15 mL of saturated ferric chloride solution, the temperature of the saturated ferric chloride solution is 50-60℃, and the reaction time is 2 h to complete the surface modification of the carbon nanotubes. The adsorption and mass transfer effect of the carbon nanotubes is improved by the mixed acid modification, and the composite material has good catalytic performance by loading iron, so that the insoluble organic waste gas realizes the multi-process synergistic effect of "mass transfer-adsorption-catalysis" on the surface of the composite material.

[0021] Preferably, in the step d), 30% hydrogen peroxide solution is added to every 1 L of water, the volume of the hydrogen peroxide solution is 0.8-1.5 mL, the mass of the Fe3O4 / SnS2 composite microspheres is 0.3-1 g, and the mass of the carbon nanotubes modified by the mixed acid and the ferric chloride solution is 0.08-0.2 g to obtain the suspension.

[0022] Preferably, in the step f), the organic waste gas contains one or more of aldehydes, alcohols, acids, esters, phenols, alkanes, and aromatic hydrocarbons.

[0023] Preferably, in the step f), the wire mesh material of the wire mesh demisting device is polypropylene, the mesh diameter is 4-8 mm, the polypropylene wire mesh is fixed by a polypropylene frame, and the total thickness of the multiple layers of wire mesh is 3-8 cm.

[0024] Preferably, the circulating bubble-spraying-mist removal integrated device comprises:

[0025] a columnar reaction zone, which is provided with a gas inlet at the lower part for inputting the organic waste gas to be treated, and is provided with a gas outlet at the upper part for outputting the treated organic waste gas;

[0026] The columnar reaction zone is provided with a lower bubbling zone, a middle spray reflux zone, and an upper demisting reflux zone from bottom to top.

[0027] The lower bubbling zone is used to hold the suspension and form a multi-layered reaction solution with different functions;

[0028] The middle layer spray reflux zone is equipped with multiple atomizing nozzles. The device also includes a liquid pump, which is located outside the columnar reaction zone and is connected to the atomizing nozzles and the lower bubbling zone respectively. The liquid pump is used to pump the upper layer solution from the lower bubbling zone and form a spray liquid through the atomizing nozzles to realize the one-time reflux of the reaction liquid.

[0029] The upper demisting reflux zone is equipped with a wire mesh demisting device, which is used to absorb the mist generated by the spraying and condense the mist before returning it to the lower bubbling zone, thereby realizing the secondary reflux of the reaction liquid.

[0030] The present invention has the following beneficial effects:

[0031] This invention provides a method for the deep degradation of large-volume mixed organic waste gas, comprising the following steps: a) preparing iron(III) oxide / stannous sulfide composite microspheres; b) surface-modifying carbon nanotubes with a mixed solution of nitric acid and perchloric acid; c) surface-modifying the acid-treated carbon nanotubes with ferric chloride solution; d) mixing hydrogen peroxide, the iron(III) oxide / stannous sulfide composite microspheres, and the surface-modified carbon nanotubes to obtain a suspension; e) adding the suspension to an integrated circulating bubbling-spraying-demisting device, forming a multifunctional stratified bubbling liquid in its bubbling zone; f) pumping the upper layer of the bubbling liquid as the spray liquid in the spray return zone; g) the waste gas treated by the bubbling-spraying process is then absorbed in the demisting return zone and discharged. This method provides stable treatment efficiency for organic waste gas, enables the recycling of the reaction suspension, and significantly improves the deep purification efficiency of industrial waste gas. Attached Figure Description

[0032] Figure 1 Transmission electron microscopy (TEM) image of the iron(II) oxide / tin(II) sulfide composite microspheres prepared in Example 1.

[0033] Figure 2 A schematic diagram of the integrated circulating bubbling-spraying-demisting device;

[0034] In the diagram: 1 is the air inlet, 2 is the lower bubbling zone, 3 is the middle spray reflux zone, 4 is the upper demisting reflux zone, 5 is the liquid pump, and 6 is the air outlet. Detailed Implementation

[0035] In order to make the invention purposes, technical solutions and beneficial technical effects of the present application more clear, the present application will be described in detail below in combination with specific examples. It should be understood that the examples described in the present specification are only for the purpose of explaining the present application, and are not intended to limit the present application.

[0036] Example 1:

[0037] 2.60 g of FeCl3·6H2O, 1.35 g of sodium citrate, and 4.80 g of sodium acetate were dissolved in 80 mL of ethylene glycol (EG), and subjected to magnetic stirring at room temperature for 30 minutes. Then, the obtained yellow-brown solution was quickly transferred into a closed polytetrafluoroethylene-lined stainless steel reaction kettle, and heated to 200°C in an oven, and then kept at 200°C for 10 h. After the reaction was completed, the supernatant was slowly poured out, and the black precipitate at the bottom was separated by a strong magnet, and then washed with ethanol and deionized water for several times. The obtained product was placed in a freeze dryer for freeze drying for 24 h, to obtain Fe3O4 particles. Transmission electron microscopy showed that the diameter of the Fe3O4 particles was about 100 nm.

[0038] 0.5 g of the Fe3O4 prepared in the above step was placed in a three-necked flask, and dispersed in 100 mL of deionized water. After ultrasonic treatment for 0.5 h, 10 mL of a stannous chloride solution with a concentration of 0.04 mol·L-1 and 10 mL of a sodium sulfide solution with a concentration of 0.04 mol·L-1 were added dropwise, respectively. After reaction for 2 h, the product was separated by a strong magnet, and washed with ethanol and deionized water for several times. The obtained product was placed in a freeze dryer for freeze drying for 24 h, to obtain Fe3O4 / stannous sulfide composite microspheres. Transmission electron microscopy showed that the diameter of the composite microspheres was about 100 nm, as shown in FIG. 1. -1 -1 0.5 g of the Fe3O4 prepared in the above step was placed in a three-necked flask, and dispersed in 100 mL of deionized water. After ultrasonic treatment for 0.5 h, 10 mL of a stannous chloride solution with a concentration of 0.04 mol·L-1 and 10 mL of a sodium sulfide solution with a concentration of 0.04 mol·L-1 were added dropwise, respectively. After reaction for 2 h, the product was separated by a strong magnet, and washed with ethanol and deionized water for several times. The obtained product was placed in a freeze dryer for freeze drying for 24 h, to obtain Fe3O4 / stannous sulfide composite microspheres. Transmission electron microscopy showed that the diameter of the composite microspheres was about 100 nm, as shown in FIG. 1. Figure 1 The contents of Fe and Sn in the sample were determined by atomic emission spectrometry, and the content of S in the sample was determined by elemental analysis. The results showed that the mass fraction of SnS in the composite microspheres was 9%.

[0039] 5 g of carbon nanotubes were taken in a three-necked flask, 150 mL of a 0.2 mol / L nitric acid solution and 50 mL of a 0.1 mol / L perchloric acid solution were added, and the mixture was heated to reflux at 120°C for 2.5 h using an oil bath. The mixture was dried in a constant temperature drying oven at 80°C for 12 h to obtain mixed acid-activated carbon nanotubes.

[0040] 1 g of the mixed acid-activated carbon nanotubes were immersed in 10 mL of a saturated ferric chloride solution at 55°C for 2 h, and then centrifuged, washed, and freeze-dried.

[0041] The reaction device was as shown in FIG. 2. Figure 2 ​The illustrated integrated device of circulating bubble-spraying-mist removal comprises a lower bubble zone 2, a middle spraying reflux zone 3 and an upper mist removal reflux zone 4. The lower bubble zone 2 is filled with 45 L Fenton reaction solution, with a depth of 40 cm; the middle spraying reflux zone 3 is connected with 8 atomizing nozzles, each with a flow rate of 5 L / h, which can completely cover the lower bubble zone 2; the upper mist removal reflux zone 4 is composed of a polypropylene mesh mist eliminator and a support, with a total thickness of 5 cm and a pore size of about 4 mm.

[0042] Before the reaction starts, the Fenton solution is first pumped by the liquid pump 5 to the mist outlet until it is stable and can cover the entire reaction device, and then the total flow rate of the reaction gas path is adjusted to 2 m 3 / h, which contains air and toluene and n-octane with a concentration of 50 mg / m 3 . 48 mL of 30% hydrogen peroxide, 22.5 g of Fe3O4 / stannous sulfide composite microspheres and 4.5 g of surface-modified carbon nanotubes are added to the circulating bubble-spraying solution.

[0043] During the reaction, the mixed organic waste gas is first oxidized and degraded by the "Fenton-bubbling" process, and the undegraded organic waste gas is further adsorbed and oxidized by the "spraying-adsorption-oxidation" process and then refluxed to the "Fenton-bubbling" zone, where it is further degraded. The gas treated by the "bubbling-spraying" process is absorbed by the upper mesh mist eliminator and then refluxed to the bubbling zone for a second time, and the treated waste gas is discharged through the gas outlet.

[0044] Under the reaction conditions and corresponding reaction time, 1 mL of gas sampling needle is used to collect 1 mL of gas sample at the inlet and outlet of the reaction device, and the peak area is determined by gas chromatography-hydrogen flame ionization detector (GC-FID). The concentration of the corresponding organic compounds is obtained by standard curve method, and their removal efficiency is calculated.

[0045] The experimental results show that under the above conditions, the removal rate of toluene is 86%, and the removal rate of n-octane is 63%.

[0046] Example 2

[0047] Under the reaction conditions described in Example 1, the total flow rate of the organic waste gas and the concentration of the organic gas are changed, and the total flow rate of the reaction gas path is adjusted to 0.03 m 3 / h, which contains air and toluene and n-octane with a concentration of 800 mg / m 3 .

[0048] The experimental results show that under the above conditions, the removal rate of toluene is 98%, and the removal rate of n-octane is 87%. It is shown that the device has higher removal efficiency when treating smaller flow of organic waste gas.

[0049] Comparative Example 1

[0050] The preparation process of the Fe304 / SnS composite microspheres is the same as that of Example 1. The mass fraction of SnS in the composite microspheres is 9%.

[0051] The circulating bubble-spraying-mist removal integrated device is the same as that of Example 1. Before the reaction starts, the Fenton solution is first sucked by the self-suction pump until the mist removal is stable and the entire reaction device is covered, and then the reaction gas path is adjusted to a total flow rate of 2 m 3 / h, which contains air and toluene and n-octane each with a concentration of 50 mg / m 3 . In the circulating bubble-spraying solution, 48 mL of 30% hydrogen peroxide, 22.5 g of Fe304 / SnS composite microspheres, and 4.5 g of unmodified carbon nanotubes are added.

[0052] The experimental results show that under the above conditions, the removal rate of toluene is 75%, and the removal rate of n-octane is 49%. Compared with Example 1, the removal rate of Comparative Example 1 decreases greatly due to the addition of unmodified carbon nanotubes.

[0053] Comparative Example 2

[0054] The preparation process of the Fe304 / SnS composite microspheres is the same as that of Example 1. The mass fraction of SnS in the composite microspheres is 9%.

[0055] The mixed acid activation of the carbon nanotubes and the treatment process of the saturated ferric chloride solution are the same as those of Example 1.

[0056] The circulating bubble-spraying-mist removal integrated device is the same as that of Example 1, except that the spraying pump on the integrated device is closed. Before the reaction starts, the reaction gas path is adjusted to a total flow rate of 2 m 3 / h, which contains air and toluene and n-octane each with a concentration of 50 mg / m 3 . In the device, 48 mL of 30% hydrogen peroxide, 22.5 g of Fe304 / SnS composite microspheres, and 4.5 g of surface-modified carbon nanotubes are added.

[0057] The experimental results show that under the above conditions, the removal rate of toluene is 67%, and the removal rate of n-octane is 51%. Compared with Example 1, the removal rate of Comparative Example 2 decreases greatly due to the stop of the spraying zone.

[0058] Comparative Example 3

[0059] The preparation process of the Fe3O4 particles is the same as that of Example 1, and the diameter is about 100 nm. The Fe3O4 particles are not compounded with SnS.

[0060] The mixed acid activation of carbon nanotubes and the treatment process of saturated ferric chloride solution were the same as in Example 1. The circulating bubble-spraying-mist-eliminating integrated device was the same as in Example 1. Before the reaction started, the Fenton reagent solution was first sucked by the self-suction pump until the mist was stable and could cover the entire reaction device, and then the reaction gas path was adjusted to a total flow rate of 2 m 3 / h, which contained air and toluene and n-octane each with a concentration of 50 mg / m 3 . In the circulating bubble-spraying solution, 48 mL of 30% hydrogen peroxide, 22.5 g of Fe3O4 particles, and 4.5 g of surface-modified carbon nanotubes were added.

[0061] The experimental results showed that under the above conditions, the removal rate of toluene was 64%, and the removal rate of n-octane was 54%. In Comparative Example 3, only Fe3O4 nanoparticles were added, and no Fe3O4 / Stannous sulfide composite microspheres were added, and the removal rate decreased more greatly compared with Example 1.

[0062] Comparative Example 4

[0063] The preparation process of Fe3O4 / Stannous sulfide composite microspheres was the same as in Example 1, and the mass fraction of SnS in the composite microspheres was 9%.

[0064] The circulating bubble-spraying-mist-eliminating integrated device was the same as in Example 1, except that the spraying pump on the reaction integrated device was closed. Before the reaction started, the reaction gas path was adjusted to a total flow rate of 2 m 3 / h, which contained air and toluene and n-octane each with a concentration of 50 mg / m 3 . In the device, 48 mL of 30% hydrogen peroxide and 22.5 g of Fe3O4 / Stannous sulfide composite microspheres were added.

[0065] The experimental results showed that under the above conditions, the removal rate of toluene was 36%, and the removal rate of n-octane was 19%. In Comparative Example 4, the spraying zone stopped working, and no carbon nanotubes were added, and the removal rate decreased more greatly compared with Example 1.

[0066] Comparative Example 5

[0067] The preparation process of Fe3O4 particles was the same as in Example 1, and the diameter was about 100 nm.

[0068] 0.5 g of the above-prepared Fe3O4 was placed in a three-necked flask and dispersed in 100 mL of deionized water. After ultrasonic treatment for 0.5 h, 10 mL of a stannous chloride solution with a concentration of 0.50 mol·L -1 was added dropwise, followed by the addition of 10 mL of a stannous chloride solution with a concentration of 0.50 mol·L -1Sodium sulfide solution, after 2h reaction, magnetic separation, washed with ethanol and deionized water several times, the obtained product was placed in a freeze dryer and freeze-dried for 24h to obtain Fe3O4 / SnS2 composite microspheres. Transmission electron microscopy showed that the sample had agglomeration, the composite microspheres had uneven particle size, and some composite microspheres with particle size less than 100nm appeared. The contents of Fe and Sn in the sample were determined by atomic emission spectrometry, and the content of S in the sample was determined by elemental analyzer. The results showed that the mass fraction of SnS in the composite microspheres was 42%.

[0069] The mixed acid activation of carbon nanotubes and the treatment process of immersing in saturated ferric chloride solution were the same as in Example 1.

[0070] The circulating bubble-spraying-mist removal integrated device was the same as in Example 1. Before the reaction started, the Fenton reagent was first sucked by the self-priming pump until the mist was stable and could cover the entire reaction device, and then the reaction gas path was adjusted to a total flow rate of 2m 3 / h, which contained air and toluene and n-octane with a concentration of 50mg / m 3 each. 48mL of 30% hydrogen peroxide, 22.5g of Fe3O4 / SnS2 composite microspheres and 4.5g of surface modified carbon nanotubes were added to the circulating bubble-spraying solution.

[0071] The experimental results showed that under the above conditions, the removal rate of toluene was 75% and the removal rate of n-octane was 57%.

[0072] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Any skilled person in the art can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present application, and these modifications or replacements should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be determined by the protection scope of the claims.

Claims

1. A method for deep degradation of large-flow-rate mixed organic waste gas, characterized in that, Includes the following steps: a) Iron oxide particles were prepared by hydrothermal method. The prepared iron oxide particles were dispersed in deionized water to obtain a suspension. Stannous chloride solution and sodium sulfide solution were added dropwise to the iron oxide suspension to obtain iron oxide / stannous sulfide composite microspheres. b) Surface modification of carbon nanotubes using a mixed solution of nitric acid and perchloric acid; c) The acid-treated carbon nanotubes were immersed in a saturated ferric chloride solution for reaction. After the reaction was completed, they were centrifuged, washed and freeze-dried. d) A mixed suspension is obtained by mixing hydrogen peroxide, the iron(II) oxide / stannous sulfide composite microspheres and the carbon nanotubes modified with acid and ferric chloride solution. The mixed suspension is added to the integrated circulating bubbling-spraying-demisting device, forming a multi-layered reaction liquid in the lower bubbling zone of the integrated device. e) Pump the upper layer solution from the lower bubbling zone as the spray liquid for the middle layer spray reflux zone of the integrated device; f) The mixed organic waste gas is introduced into the above-mentioned integrated device. The organic waste gas first undergoes mass transfer, adsorption, and catalytic oxidation processes in the lower bubbling zone, and then enters the middle spray reflux zone for recirculation. The gas treated by the above bubbling-spraying process is absorbed by the wire mesh demister in the upper demisting reflux zone. After the mist condenses, it is recirculated to the lower bubbling zone for the second time. The treated waste gas is discharged through the outlet.

2. The method according to claim 1, characterized in that, In step a), each 1g of iron oxide particles is dispersed in 180-250mL of deionized water.

3. The method according to claim 2, characterized in that, In step a), the volume of stannous chloride solution added is 8–30 mL, and the molar concentration is 1.33 × 10⁻⁶. -5 ~0.11 mol·L -1 The volume of sodium sulfide solution added is 8–30 mL, with a molar concentration of 1.33 × 10⁻⁶. -5 ~0.11 mol·L -1 .

4. The method according to claim 3, characterized in that, In step a), the particle size of the iron oxide / tin sulfide composite microspheres is 90-120 nm, and the mass percentage of tin sulfide is 4%-35%.

5. The method according to claim 1, characterized in that, In step b), for every 1g of carbon nanotubes, 20-40mL of nitric acid solution is added, with a concentration of 0.15-0.25 mol / L; 5-15mL of perchloric acid solution is added, with a concentration of 0.05-0.12 mol / L; after adding the mixed acid, the mixture is heated under constant temperature reflux at 120℃ for 2-4 h using an oil bath.

6. The method according to claim 1, characterized in that, In step c), each 1g of acid-treated carbon nanotubes is immersed in 8-15mL of saturated ferric chloride solution at a temperature of 50-60℃ for 2 hours to complete the surface modification of the carbon nanotubes.

7. The method according to claim 1, characterized in that, In step d), a 30% hydrogen peroxide solution is added to every 1L of water, with a volume of 0.8–1.5 mL. 0.3–1 g of iron(II,III) oxide / stannous sulfide composite microspheres are added, along with 0.08–0.2 g of carbon nanotubes modified with mixed acid and ferric chloride solution, to obtain the mixed suspension.

8. The method according to claim 1, characterized in that, In step f), the organic waste gas contains one or more of aldehydes, alcohols, acids, esters, phenols, alkanes, and aromatic hydrocarbons.

9. The method according to claim 1, characterized in that, In step f), the wire mesh of the wire mesh defogging device is made of polypropylene with a mesh diameter of 4-8 mm. The polypropylene wire mesh is fixed by a polypropylene frame, and the total thickness of the multi-layer wire mesh is 3-8 cm.

10. The method according to claim 1, characterized in that, The integrated circulating bubbling-spraying-demisting device includes: The columnar reaction zone has an air inlet at the bottom for inputting the organic waste gas to be treated, and an air outlet at the top for outputting the treated organic waste gas. The columnar reaction zone is provided with a lower bubbling zone, a middle spray reflux zone, and an upper demisting reflux zone from bottom to top. The lower bubbling zone is used to hold the mixed suspension and form a multi-layered reaction solution with different functions; The middle layer spray reflux zone is equipped with multiple atomizing nozzles. The device also includes a liquid pump, which is located outside the columnar reaction zone and is connected to the atomizing nozzles and the lower bubbling zone respectively. The liquid pump is used to pump the upper layer solution from the lower bubbling zone and form a spray liquid through the atomizing nozzles. The upper demisting return zone is equipped with a wire mesh demisting device, which is used to absorb the mist generated by the spray and condense the mist before returning it to the lower bubbling zone.

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