A carbon nanotube modified carbon cloth electrode with controllable structure and a preparation method and application thereof

Abstract

The application discloses a carbon nanotube modified carbon cloth electrode with a controllable structure and a preparation method and application thereof. The application takes carbon cloth as a substrate, a transition metal nitrate as a catalyst, toluene as a carbon source, and water vapor as a reducing agent and a growth promoter. A precursor solution composed of toluene and water is vaporized and injected into a high-temperature tubular furnace. By adjusting parameters such as catalyst concentration, water vapor content, carrier gas flow rate, precursor solution injection speed, and reaction time, the growth density, length, and surface functional groups of the carbon nanotubes are controlled, thereby promoting the adsorption and electrocatalytic performance of the obtained electrode. The application has mild reaction conditions and a simple preparation method. The carbon nanotube modified carbon cloth electrode prepared by the application is used for adsorption-electrooxidation of oxygen-containing volatile organic compounds, realizes excellent degradation performance of rapid degradation after adsorption, greatly improves the degradation performance of refractory oxygen-containing volatile organic compounds and the stability of the electrode, and can be widely applied to treatment of refractory volatile organic compounds.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of air pollution control, and relates to a nanomaterial preparation technology and an adsorption-electrochemical oxidation treatment technology for refractory oxygen-containing volatile organic compounds, in particular to a carbon nanotube modified carbon cloth electrode with adjustable structure and a preparation method and application thereof. BACKGROUND

[0002] The emission of toxic, high-molecular, and refractory oxygen-containing volatile organic compounds in volatile organic compounds (VOCs) poses a challenge to traditional treatment methods such as adsorption, absorption, and microorganism treatment. Therefore, it is necessary to develop a treatment method with good environmental compatibility, small land occupation, and strong oxidation capacity. Electrochemical oxidation as a kind of advanced treatment system has been successfully used in the research on refractory organic pollutants.

[0003] Anodic oxidation is considered as an effective technology, and even can decompose the most refractory organic pollutants. Carbon nanotubes are widely used in anode modification due to their unique electrical conductivity, porous structure, and adjustable surface electrochemical performance. In addition, in-situ grown CNTs can adjust their electrocatalytic performance through preparation conditions, and also avoid the problems of poor apparent catalytic activity and poor working stability caused by coating and electrophoretic deposition methods. Chinese Patent CN 113044830 A discloses a preparation method of in-situ grown carbon nanotube / graphene composite sponge, which adjusts the morphology of carbon nanotubes by adjusting the concentration of nickel nitrate and the gas deposition time, and improves the electrical conductivity and composite mechanical properties. Chinese Patent CN 110067004 A introduces a method for in-situ growth of CNTs on carbon cloth, which first loads catalyst on carbon cloth through hydrothermal reaction, and then generates carbon nanotubes through chemical vapor deposition, thereby enhancing the electrocatalytic activity and working stability. The preparation method uses hydrogen as reducing gas, which has a large safety hazard, and the preparation method is complex and tedious.

[0004] Meanwhile, carbon nanotubes exhibit significant adsorption, and are often used for adsorption and enrichment of organic pollutants. Chinese Patent CN 109092245 A introduces a preparation method of diatomite supported carbon nanotube adsorbent, which mixes diatomite as a matrix with a catalyst and performs suction filtration, and the adsorbent prepared by nitrogen, hydrogen, and carbon source (acetylene, methane, or carbon monoxide) has high adsorption capacity for phenolic organic compounds.

[0005] However, the low oxygen evolution potential of carbon anode leads to a large amount of hydroxyl radicals generated and adsorbed on the anode surface, and more participate in the oxygen evolution reaction, resulting in low organic compound degradation efficiency. At present, there are few reports on the method based on the combination of adsorption and electrochemical oxidation to improve the degradation efficiency of carbon electrode on organic pollutants, and there is no research report on the application of carbon nanotube modified carbon cloth electrode with adjustable structure to the adsorption-quick degradation technology of refractory oxygen-containing volatile organic compounds. SUMMARY

[0006] The present application aims at a carbon nanotube modified carbon cloth electrode with adjustable structure, and a preparation method and application thereof.

[0007] To achieve the above object, the technical scheme adopted by the present application is as follows.

[0008] The present application provides an application of a carbon nanotube modified carbon cloth electrode with adjustable structure in adsorption-electrochemical oxidation treatment of refractory oxygen-containing volatile organic compounds, wherein the carbon nanotube modified carbon cloth electrode with adjustable structure is prepared by the following steps:

[0009] (1) Pretreating the carbon cloth;

[0010] (2) Immersing the pretreated carbon cloth into an ethanol solution of a transition metal catalyst, ultrasonicating, and drying after the immersion to obtain the carbon cloth loaded with the catalyst;

[0011] (3) Injecting a precursor solution composed of a carbon source and water into a vaporizer, and after the vaporization of the precursor solution in the vaporizer, introducing the precursor solution together with a carrier gas into a heating tube furnace in which the carbon cloth loaded with the catalyst is arranged in the center region to grow carbon nanotubes in situ on the surface of the carbon cloth, thereby obtaining the carbon nanotube modified carbon cloth electrode.

[0012] In the present application, the refractory oxygen-containing volatile organic compounds include one or more of methyl methacrylate, cyclohexanone, methyl tert-butyl ether, benzaldehyde, and propyl acetate.

[0013] In the present application, the carbon nanotube modified carbon cloth electrode is used as an anode, a platinum sheet is used as a cathode, and a Na2SO4 solution is used as a supporting electrolyte.

[0014] In the present application, the initial concentration of the refractory oxygen-containing volatile organic compounds is 10-500 mg / L, the adsorption enrichment time is 10-30 h, the current density is 1-100 mA / cm 2 , and the electro-oxidation time is 10-200 min. Preferably, the initial concentration of the refractory oxygen-containing volatile organic compounds is 50-150 mg / L, the adsorption enrichment time is 15-25 h, the current density is 10-50 mA / cm2 The electro-oxidation time is 80-180 min.

[0015] In the present application, in step (1), the pretreatment method comprises: first, soaking the carbon cloth in acetone for 1-4 h, washing with deionized water and drying; then, condensing and refluxing in a mixed solution of concentrated sulfuric acid and concentrated nitric acid with a volume ratio of 3:1 under the condition of a water bath at 75-85℃ for 2-8 h; finally, washing with deionized water until neutral, and drying for standby use.

[0016] In the present application, in step (2), the ultrasonic time is 20-60 min, the immersion time is 6-24 h, the transition metal catalyst is one or several of ferric nitrate, nickel nitrate or aluminum nitrate, and the concentration of the transition metal catalyst solution is 0.05-0.2 mol / L.

[0017] In the present application, in step (3), the carbon source is toluene, and the molar percentage content of water in the precursor solution is 1-20%. Preferably, the molar percentage content of water in the precursor solution is 5-15%. More preferably, the molar percentage content of water in the precursor solution is 10%.

[0018] In the present application, in step (3), the carrier gas is nitrogen, the carrier gas flow rate is 100-400 ml / min, the temperature rising rate of the tube furnace is 5-10℃ / min, the precursor solution is injected into the vaporizer when the tube furnace is heated to a temperature of 500-700℃, the injection speed is 5-20 μL / min, and after the tube furnace is heated to 1000-1100℃, the temperature is continued to be kept for 1-3 h.

[0019] The present application also provides a carbon nanotube modified carbon cloth electrode with a controllable structure for the above-mentioned application.

[0020] The present application further provides a preparation method of the above-mentioned carbon nanotube modified carbon cloth electrode with a controllable structure, comprising the following steps:

[0021] (1) Pretreating the carbon cloth;

[0022] (2) Immersing the pretreated carbon cloth into an ethanol solution of a transition metal catalyst, ultrasonicating, and drying after immersion, to obtain a carbon cloth loaded with the catalyst;

[0023] (3) Injecting a precursor solution composed of a carbon source and water into a vaporizer, and after the precursor solution is vaporized in the vaporizer, it enters a heating tube furnace together with a carrier gas, the heating tube furnace is provided with the carbon cloth loaded with the catalyst in the center region, carbon nanotubes are grown in situ on the surface of the carbon cloth, and a carbon nanotube modified carbon cloth electrode is obtained.

[0024] In the present application, in step (3), when chemical vapor deposition is used to grow carbon nanotubes, the equipment used mainly consists of a micro-injection pump, a carrier gas, a gas flow meter, and a vaporizer and a tube furnace, the carrier gas is controlled by the gas flow meter and enters the vaporizer in two ways with the micro-injection pump, the vaporizer is connected with the tube furnace. The tube furnace is a horizontal high-temperature tube furnace, the micro-injection pump is filled with a precursor solution of carbon source and water, and water is used as a growth aid and a reducing agent; the vaporizer can stabilize the precursor solution and mix with the carrier gas in the vaporizer to produce a continuous and stable concentration of precursor gas, which is introduced into the tube furnace.

[0025] In the present application, in step (3), the carrier gas is nitrogen, and the influencing factors can be adjusted: the water content is 1-20%, the carrier gas flow is 100-400ml / min, the temperature rising rate of the tube furnace is 5-10℃ / min, the micro-injection pump is started to inject the precursor solution when the tube furnace is heated to a temperature of 500-700℃, the speed of the micro-injection pump injecting the precursor solution is 5-20μL / min, and after the high-temperature tube furnace is heated to 1000-1100℃, it continues to be kept for 1-3h.

[0026] Compared with the prior art, the present application has the following advantages,

[0027] (1) The carbon nanotube modified carbon cloth electrode in the present application uses water as a reducing agent and a growth aid, the reaction conditions are mild, and the preparation method is simple.

[0028] (2) In the present application, the catalyst concentration is used to adjust the growth density and diameter of the carbon nanotubes, the reaction temperature, reaction time, and nitrogen flow rate are used to control the length of the carbon nanotubes, and the water content can be used to control the density and diameter of the carbon nanotubes, and also affect the surface functional groups and defects of the carbon nanotubes, thereby promoting the adsorption and electrocatalytic performance of the electrode, meeting different use requirements, and expanding the application range of the material.

[0029] (3) The carbon nanotube modified carbon cloth electrode in the present application has strong adsorption performance and electrocatalytic performance. Using the carbon nanotube modified carbon cloth in the present application as an anode, the adsorption-electrooxidation technology is used to solve the limitation of the low oxygen evolution potential of the carbon electrode as an electrocatalytic anode, and the surface hydroxyl radicals generated by the adsorption enrichment and electrooxidation of organic pollutants achieve rapid degradation of adsorbed organic matter, greatly promoting the degradation efficiency of refractory oxygen-containing volatile organic compounds in industry, and is an excellent electrode with industrial application prospect.

[0030] (4) The carbon nanotube modified carbon cloth electrode in the present application has strong stability, stable operation, no secondary pollution, and can be regenerated after adsorption-electrooxidation, and still maintains high adsorption and electrocatalytic activity after multiple cycles, and has popularization value in treating refractory oxygen-containing volatile organic compounds. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 is a preparation system diagram of a carbon nanotube modified carbon cloth electrode with a controllable structure according to the present application.

[0032] Figure 2 is a scanning electron microscope (SEM) diagram of an anode carbon cloth substrate prepared according to the present application.

[0033] Figure 3 is a scanning electron microscope (SEM) diagram of a carbon nanotube modified carbon cloth electrode according to embodiment 2 of the present application.

[0034] Figure 4 is a transmission electron microscope (TEM) diagram of a carbon nanotube modified carbon cloth electrode according to embodiment 2 of the present application.

[0035] Figure 5 is an X-ray diffraction (XRD) diagram of a carbon nanotube modified carbon cloth electrode according to embodiment 2 of the present application.

[0036] Figure 6 is a cyclic voltammetry (CV) diagram for evaluating electrocatalytic performance according to embodiment 2 of the present application.

[0037] Figure 7 is an electrochemical impedance spectroscopy (EIS) diagram for evaluating electrocatalytic performance according to embodiment 2 of the present application.

[0038] Figure 8 is a diagram showing the effect of different initial concentrations of methyl methacrylate on the adsorption-electrooxidation of the electrode according to embodiment 2 of the present application.

[0039] Figure 9 is a diagram showing the effect of different current densities on the adsorption-electrooxidation of methyl methacrylate according to embodiment 2 of the present application.

[0040] Figure 10 is a diagram showing the stability of a carbon nanotube modified carbon cloth anode according to embodiment 2 of the present application.

[0041] Figure 11 is a diagram showing the comparative effect of the prepared electrode on the adsorption and adsorption-electrooxidation of methyl methacrylate according to embodiment 4 of the present application. DETAILED DESCRIPTION

[0042] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to specific embodiments. The present application will be described below with reference to the accompanying drawings and specific embodiments, but the present application is not limited to the following embodiments.

[0043] Figure 1The application is a preparation system diagram of a carbon nanotube modified carbon cloth electrode with adjustable structure, which comprises a micro-injection pump, a carrier gas, a gas flow meter, a vaporizer and a high-temperature tube furnace; the carrier gas is controlled by the gas flow meter and enters the vaporizer in two ways with the micro-injection pump, and the vaporizer is connected with the high-temperature tube furnace. The high-temperature tube furnace is horizontal, and the micro-injection pump is filled with a precursor solution of a carbon source and a growth aid / reducing agent; the vaporizer can stably vaporize the precursor solution and mix with the carrier gas in the vaporizer to generate a continuous and stable concentration of precursor gas into the tube furnace.

[0044] In the embodiment, the carbon nanotube modified carbon cloth electrode with adjustable structure is prepared first, and then is used for adsorption-electrochemical oxidation treatment of refractory oxygen-containing volatile organic compounds, which specifically comprises the following steps:

[0045] (1) The carbon cloth is soaked in acetone for 1-4 h for cleaning, washed with deionized water and dried. The water bath is kept at a certain temperature of 75-85°C, and is placed in a mixed solution of concentrated sulfuric acid and concentrated nitric acid with a volume ratio of 3:1 for condensation reflux for 2-8 h. Wash with deionized water until neutral, and dry for standby;

[0046] (2) The pretreated carbon cloth is immersed in an ethanol solution of a transition metal catalyst, ultrasonicated, and dried after immersion to obtain a carbon cloth loaded with the catalyst;

[0047] (3) The precursor solution composed of a carbon source and water is injected into the vaporizer, and the vaporized precursor solution in the vaporizer enters the heating tube furnace together with the carrier gas, in which the carbon cloth loaded with the catalyst is arranged in the central area, to grow carbon nanotubes on the surface of the carbon cloth in situ, thereby obtaining a carbon nanotube modified carbon cloth electrode.

[0048] (4) The carbon nanotube modified carbon cloth electrode with adjustable structure prepared in step (3) is used as an anode, a platinum sheet is used as a cathode, and Na2SO4 is used as a supporting electrolyte. The carbon nanotube modified carbon cloth electrode is first immersed in an oxygen-containing volatile organic compound solution for adsorption enrichment, and then is used for electrochemical oxidation of refractory organic pollutants in a constant current mode.

[0049] Example 1

[0050] Firstly, carbon cloth (2*2cm) was immersed in acetone for 3h to remove dirt, washed with deionized water and dried, then placed in a mixed solution of concentrated sulfuric acid and concentrated nitric acid with a volume ratio of 3:1 at 80℃ for condensation reflux for 6h, washed with deionized water until neutral, and dried for standby use. After acid treatment, the carbon cloth was immersed in an ethanol prepared 0.1M iron nitrate catalyst solution for ultrasonic treatment for 30min, and then dried after immersion for 8h to obtain a catalyst-loaded carbon cloth. The catalyst-loaded carbon cloth was placed in a tube furnace, protected by 350ml / min nitrogen gas, and the high-temperature tube furnace was heated to 700℃ at a rate of 5℃ / min. When the temperature reached 700℃, a micro-injection pump was started to inject the precursor solution. The high-temperature tube furnace was heated to a maximum temperature of 1100℃, and the reaction time was maintained for 3h. The speed of the micro-injection pump injecting the precursor was 10μL / min, and the molar percentage of water was 5% (calculated by the molar ratio of water to toluene). The prepared electrode was named CNTs-CC-1.

[0051] The CNTs-CC-1 electrode prepared by the above method was used as the anode (2*2cm), and platinum sheet (2*2cm) was used as the cathode. The electrolyte was 100mL of 0.05M Na2SO4 solution (pH=7), and the initial concentration of methyl methacrylate was 100mg / L. The anode prepared by the method was first placed in the pollutant solution in the reactor for 24h to achieve adsorption equilibrium, and then a constant current density of 10mA / cm 2 The current density was constant current degradation, the reaction time was 150min, and the electrode spacing was 1cm.

[0052] The adsorption-electro-oxidation effect of the carbon nanotube modified anode on methyl methacrylate was investigated. The removal efficiency was 38.99% after 24h of adsorption, and the removal efficiency of methyl methacrylate was 70.45% after 150min of degradation.

[0053] Example 2

[0054] Firstly, carbon cloth (2*2cm) was immersed in acetone for 3h to remove dirt, washed with deionized water and dried, then placed in a mixed solution of concentrated sulfuric acid and concentrated nitric acid with a volume ratio of 3:1 at 80℃ for condensation reflux for 6h, washed with deionized water until neutral, and dried for standby use. After acid treatment, the carbon cloth was immersed in an ethanol prepared 0.1M iron nitrate catalyst solution for ultrasonic treatment for 30min, and then dried after immersion for 8h to obtain a catalyst-loaded carbon cloth. The catalyst-loaded carbon cloth was placed in a tube furnace, protected by 350ml / min nitrogen gas, and the high-temperature tube furnace was heated to 700℃ at a rate of 5℃ / min. When the temperature reached 700℃, a micro-injection pump was started to inject the precursor solution. The high-temperature tube furnace was heated to a maximum temperature of 1100℃, and the reaction time was maintained for 3h. The speed of the micro-injection pump injecting the precursor was 10μL / min, and the molar percentage of water was 5% (calculated by the molar ratio of water to toluene). The prepared electrode was named CNTs-CC-1.

[0055] From Figure 2 andFigure 3 As can be seen from the SEM image, the preparation method in situ grows dense tubular CNTs on the smooth carbon cloth surface, which evenly covers the carbon cloth surface; Figure 4 It can be seen from the TEM image that the preparation method produces micron-sized carbon nanotubes; Figure 5 From the XRD pattern, it can be seen that the preparation method can detect the characteristic diffraction peak of carbon at 26.26°, which corresponds to the (002) plane of CNT.

[0056] The prepared carbon nanotube-modified carbon cloth CNTs-CC-2 and untreated carbon cloth CC were used as anodes (1*1 cm), and measurements were performed using an electrochemical workstation in a three-electrode system. A platinum electrode (2*2 cm) and Ag / AgCl were used as auxiliary and reference electrodes, respectively. Cyclic voltammetry (CV) was performed in 0.5 M Na2SO4 solution at 50 mVs -1 Scan rate measurement. Figure 6 As shown in Figure 2, the two electrodes clearly show almost reversible redox peaks and exhibit similar surface electrochemical behaviors. The anodic peak current value of the carbon nanotube modified carbon cloth electrode CNTs-CC-2 prepared in Example 2 is 0.0257 A / cm 2 The anodic peak current value of the untreated carbon cloth CC is 0.0168 A / cm 2 .

[0057] The prepared carbon nanotube-modified carbon cloth CNTs-CC-2 and untreated carbon cloth CC were used as anodes, respectively. Measurements were performed using an electrochemical workstation in a three-electrode system, with a platinum electrode (2*2 cm) and Ag / AgCl as the auxiliary electrode and reference electrode, respectively. Electrochemical impedance spectroscopy (EIS) was performed in a 0.5 M Na2SO4 solution with a sweep frequency range of 100 kHz to 100 mHz and a sine wave with a 10 mV amplitude. The EIS data were fitted using an equivalent circuit model, as shown in Figure 2. Figure 7 As shown, the carbon nanotube-modified carbon cloth electrode CNTs-CC-2 prepared in Example 2 has an equivalent series resistance (Rs) of 2.35Ω and a charge transfer resistance (Rct) of 2.41Ω. The untreated carbon cloth CC has an equivalent series resistance (Rs) of 3.02Ω and a charge transfer resistance (Rct) of 2.93Ω.

[0058] The carbon nanotube-modified carbon cloth CNTs-CC-2 prepared in Example 2 was used as the anode (2*2 cm), a platinum sheet (2*2 cm) was used as the cathode, 100 mL of 0.05 M Na2SO4 solution (pH = 7) was used as the electrolyte, and the initial concentrations of methyl methacrylate were 100, 150, and 250 mg / L, respectively. The anode prepared by the method was first placed in the reactor pollutant solution for 24 hours to achieve adsorption equilibrium, and then a 10 mA / cm2 Current density constant current degradation, reaction time 120 min, electrode spacing 1 cm. As shown in Figure 8 methyl methacrylate initial concentration of 100, 150, 250 mg / L, respectively, the adsorption-electro-oxidation degradation efficiency of CNTs-CC-2 on methyl methacrylate reached 79.28%, 92.20%, 97.26% respectively in 150 min.

[0059] The carbon nanotube modified carbon cloth CNTs-CC-2 prepared in the embodiment 2 was used as anode (2*2 cm), and platinum plate (2*2 cm) was used as cathode, and 100 mL of 0.05 M Na2SO4 solution (pH=7) was used as electrolyte, and the initial concentration of methyl methacrylate was 250 mg / L. The anode prepared by the method was first placed in the pollutant solution in the reactor for 24 h to achieve adsorption equilibrium, and the current density was 10, 30, 50 mA / cm 2 Current density constant current degradation, reaction time 120 min, electrode spacing 1 cm. As shown in Figure 9 , when the current density was 10, 30, 50 mA / cm 2 , the adsorption-electro-oxidation degradation efficiency of CNTs-CC-2 on methyl methacrylate reached 93.74%, 96.90%, 100% respectively in 120 min.

[0060] As shown in Figure 10 , the electrode prepared in the embodiment 2 was used for 13 adsorption-electro-oxidation cycle experiments for methyl methacrylate with initial concentration of 100 mg / L, and the adsorption capacity of the prepared electrode on methyl methacrylate reached 2.2 mg / cm 2 The degradation efficiency was more than 85%, which had excellent stability.

[0061] Embodiment 3

[0062] First, the carbon cloth (2*2 cm) was soaked in acetone for 3 h to remove dirt, washed with deionized water and dried, and then placed in a mixed solution of concentrated sulfuric acid and concentrated nitric acid with a volume ratio of 3:1 at 80°C for condensation reflux for 6 h, washed with deionized water until neutral, and dried for standby. After acid treatment, the carbon cloth loaded with catalyst was immersed in an ethanol prepared 0.1 M ferric nitrate catalyst solution for ultrasonic treatment for 30 min, and then dried after immersion for 8 h to obtain the carbon cloth loaded with catalyst. The carbon cloth loaded with catalyst was placed in a tube furnace, and under the protection of 350 ml / min nitrogen gas, the high temperature tube furnace was heated to 700°C at a rate of 5°C / min, and then a micro-injection pump was used to inject the precursor solution. The high temperature tube furnace was heated to 1100°C, and the reaction time was maintained for 3 h. The speed of the micro-injection pump for injecting the precursor was 10 μL / min, and the molar percentage content of water vapor was 15%. The prepared electrode was named as CNTs-CC-3.

[0063] CNTs-CC-3 electrode prepared by the above method was used as anode (2*2 cm), and platinum plate (2*2 cm) was used as cathode, 100 mL of 0.05 M Na2SO4 solution (pH=7) was used as electrolyte, and the initial concentration of methyl methacrylate was 100 mg / L. The anode prepared by the method was first placed in the pollutant solution in the reactor for 24 h to achieve adsorption equilibrium, and then 10 mA / cm 2 The current density was constant current degradation, the reaction time was 150 min, and the electrode distance was 1 cm.

[0064] The adsorption-electrooxidation effect of the carbon nanotube modified anode on methyl methacrylate was investigated, and the removal efficiency was 42.91% after 24 h of adsorption. After 150 min of degradation, the removal efficiency of methyl methacrylate was 78.30%.

[0065] Example 4

[0066] CNTs-CC-2 and untreated carbon cloth CC prepared in Example 2 above were used as anode (2*2 cm), platinum plate (2*2 cm) was used as cathode, 100 mL of 0.05 M Na2SO4 solution (pH=7) was used as electrolyte, and the initial concentration of methyl methacrylate was 100 mg / L. 10 mA / cm 2 The current density was constant current degradation, the reaction time was 150 min, and the electrode distance was 1 cm. The electrooxidation and adsorption-electrooxidation degradation effects of the electrodes on methyl methacrylate were compared.

[0067] As shown in Figure 11 After 150 min, the electrooxidation degradation efficiency of CC on methyl methacrylate was 12.05%, and the adsorption-electrooxidation degradation efficiency was 73.09%; the electrooxidation degradation efficiency of CNTs-CC-2 on methyl methacrylate was 18.48%, and the adsorption-electrooxidation degradation efficiency was 79.28%.

Claims

1. Application of a carbon cloth electrode modified with adjustable structure in the adsorption-electrochemical oxidation treatment of refractory oxygen-containing volatile organic compounds, characterized in that: The carbon nanotube-modified carbon cloth electrode with adjustable structure is prepared by the following steps: (1) Pretreatment of carbon cloth; (2) immersing the pretreated carbon cloth in an ethanol solution of a transition metal catalyst, ultrasonicating, and drying after immersion to obtain a catalyst-loaded carbon cloth; (3) Injecting a precursor solution consisting of a carbon source and water into a vaporizer, the precursor solution is vaporized in the vaporizer and then enters a heating tube furnace with a catalyst-loaded carbon cloth disposed in the central region together with a carrier gas, and carbon nanotubes are in situ grown on the surface of the carbon cloth to obtain a carbon nanotube-modified carbon cloth electrode; wherein: The refractory oxygen-containing volatile organic compounds include one or more of methyl methacrylate, cyclohexanone, methyl tert-butyl ether, benzaldehyde, and propyl acetate; In step (2), the transition metal catalyst is one or more of ferric nitrate, nickel nitrate or aluminum nitrate; In step (3), the carbon source is toluene, and the molar percentage content of water in the precursor solution is 1-20%.

2. The use according to claim 1, characterized in that A carbon nanotube-modified carbon cloth electrode was used as the anode, a platinum sheet as the cathode, and a Na2SO4 solution as the supporting electrolyte. The carbon nanotube-modified carbon cloth electrode was first immersed in a solution of difficult-to-degrade oxygenated volatile organic compounds for adsorption and enrichment, and then the oxygenated volatile organic compounds were electro-oxidized and degraded under constant current mode.

3. The use according to claim 1, characterized in that The initial concentration of difficult-to-degrade oxygenated volatile organic compounds is 10-500 mg / L; the adsorption enrichment time is 10-30 hours, and the current density is 1-100 mA / cm 2 , the electro-oxidation time is 10-200min.

4. The use according to claim 1, characterized in that In step (1), the pretreatment method includes: first, soaking the carbon cloth in acetone for 1-4 hours, rinsing with deionized water and drying; then, placing the carbon cloth in a mixed solution of concentrated sulfuric acid and concentrated nitric acid with a volume ratio of 3:1 in a water bath at 75-85°C and condensing and refluxing for 2-8 hours; finally, washing with deionized water until neutral, and drying for later use.

5. The use according to claim 1, characterized in that In step (2), the ultrasonication time is 20-60 min, the immersion time is 6-24 h, and the concentration of the transition metal catalyst solution is 0.05-0.2 mol / L.

6. The use according to claim 1, characterized in that In step (3), the carrier gas is nitrogen, the carrier gas flow rate is 100-400 ml / min, the heating rate of the tube furnace is 5-10°C / min, and the precursor solution is injected into the vaporizer when the tube furnace is heated to 500-700°C. The injection speed is 5-20 μL / min. After the tube furnace is heated to 1000-1100°C, it is kept warm for 1-3 hours.

7. A carbon nanotube-modified carbon cloth electrode with a controllable structure for use in any one of claims 1 to 6.

8. A method for preparing a carbon nanotube-modified carbon cloth electrode with a controllable structure according to claim 7, characterized in that: The following steps are involved: (1) Pretreatment of carbon cloth; (2) immersing the pretreated carbon cloth in an ethanol solution of a transition metal catalyst, ultrasonicating, and drying after immersion to obtain a catalyst-loaded carbon cloth; (3) A precursor solution consisting of a carbon source and water is injected into a vaporizer. After being vaporized in the vaporizer, the precursor solution enters a heating tube furnace with a catalyst-loaded carbon cloth in the central area together with a carrier gas, and carbon nanotubes are grown in situ on the surface of the carbon cloth to obtain a carbon nanotube-modified carbon cloth electrode.

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