A reaction system and a degradation method for electrocatalytic degradation of organic halides in wastewater

Abstract

The present application belongs to the field of catalysis and environment technology, and particularly relates to a reaction system and a degradation method for electrocatalytic degradation of organic halides in wastewater. The electrochemical reaction system comprises a reactor, a liquid storage tank and a direct current power supply. The reactor further comprises an electrocatalytic anode with a three-dimensional net structure and / or an electrocatalytic cathode with a three-dimensional cluster structure. A peristaltic pump is connected between the reactor and the liquid storage tank. The electrocatalytic anode or the electrocatalytic cathode is designed to have a three-dimensional structure with a large number of void spaces, which improves the uniformity of the diffusion of wastewater in the reactor. The peristaltic pump is introduced to further improve the uniform distribution of pollutants, greatly increasing the reaction probability of the pollutants with active species, thereby significantly improving the degradation rate and efficiency of organic halides. Moreover, the method is economical and feasible, and does not cause secondary pollution, which is expected to broaden the thinking in the practical application of electrocatalysis or light-assisted electrocatalysis for the degradation of organic halide wastewater.

Description

Technical Field

[0001] This invention belongs to the field of catalysis and environmental technology, specifically relating to a reaction system and degradation method for electrocatalytic degradation of organic halides in wastewater. Background Technology

[0002] Protecting the water environment from pollution is a social issue of widespread concern to humankind. With the development of modern industry, the use of various organohalides and the discharge of organohalide wastewater have caused pollution of surface water environments. Most of these organohalides are highly toxic, difficult to degrade, and bioaccumulate in certain environments, posing a direct threat to the water environment and human health.

[0003] Carbon-halogen bonds generally have high bond energies, such as the C-C bond (452 ​​kJ / mol), C-Cl bond (351 kJ / mol), C-Br bond (293 kJ / mol), and Cl bond (234 kJ / mol). These high bond energies make it difficult for halogen atoms to leave the bond, requiring a high energy injection to break them. Furthermore, due to the strong electronegativity of halogen atoms and the presence of adjacent electron-deficient carbons, they are difficult for electrophiles to attack and undergo oxidation reactions.

[0004] Traditional methods for treating various organic halides in water bodies include physicochemical treatment and biodegradation. However, physicochemical methods have low treatment efficiency, while the reaction conditions and product control of biodegradation technology are more complex, which limits its application.

[0005] Electrocatalytic oxidation-reduction (ORR) is a process that directly oxidizes and reduces pollutant molecules through electrochemical processes, or generates high-energy reactive species with oxidation-reduction capabilities to break carbon-halogen bonds and degrade halide molecules. Photo-assisted electrocatalytic OOR technology, compared to electrocatalytic OOR water treatment technology, introduces a large number of semiconductor electrodes. This not only broadens the range of electrode materials but also allows for the efficient separation of electrons and holes in the semiconductor using an external electric field, thus significantly improving performance compared to traditional photocatalysis. Furthermore, by integrating the semiconductor catalyst into the photoelectrode, the distance to light exposure is controllable, the oxidation-reduction sites are spatially separated, and it is easily separated from the water system compared to traditional photocatalytic treatment.

[0006] Based on the advantages of the aforementioned electrocatalytic oxidation and photo-assisted electrocatalytic oxidation technologies, this invention attempts to propose the use of electrocatalytic oxidation or photo-assisted electrocatalytic oxidation to degrade organic halides in wastewater.

[0007] The electrocatalytic oxidation degradation of organohalides mainly includes the direct oxidation of pollutant molecules by the electrode and the indirect oxidation of pollutant molecules by high-energy active species. The direct oxidation process is limited by the limiting reaction rate when the pollutant concentration is high, while the indirect oxidation process degrades organohalide molecules by catalyzing the formation of active species or the cycling of redox ion pairs through electrode reactions.

[0008] The photo-assisted electrocatalytic oxidation degradation of organohalides utilizes reducing substances (nucleophiles) to directly attack the positively charged carbon atoms bonded to halogen atoms. This easily breaks the carbon-halogen bond, which is then coupled with the anodic oxidation process to achieve efficient degradation and mineralization of organohalide molecules.

[0009] However, there are currently no reports on technologies for using electrocatalytic oxidation to degrade organohalides in wastewater. Summary of the Invention

[0010] To address the problems of low treatment efficiency and difficulty in controlling reaction conditions and products in the degradation of organohalides in wastewater, this invention proposes a reaction system and degradation method for the electrocatalytic degradation of organohalides in wastewater. This electrochemical reaction system enables highly efficient degradation of organohalides, and the method using this system for degrading organohalides has the advantages of simple process, easy operation, and low cost.

[0011] In a first aspect, the present invention provides an electrochemical reaction system, comprising: a reactor, a storage tank, and a DC power supply; the reactor further comprises an electrocatalytic anode having a three-dimensional network structure and / or an electrocatalytic cathode having a three-dimensional cluster structure; the electrocatalytic anode is composed of a network metal substrate and nano-three-dimensional structures distributed thereon; and a peristaltic pump is connected between the reactor and the storage tank.

[0012] This invention has revealed that when using existing electrocatalytic oxidation technology to treat organohalide wastewater, the pollutant reaction is insufficient, and the degradation effect is difficult to achieve the expected results. The main reasons for this are poor interfacial mass transfer and slow reaction kinetics. Therefore, the inventors have attempted to optimize and adjust the electrocatalyst and pollutant concentration according to conventional methods in the field, as well as to add photo-assisted electrocatalysis and other techniques; however, the improvement effect is limited.

[0013] Through continuous and in-depth research, this invention designs the electrocatalytic anode or cathode as a mesh structure, enabling uniform diffusion of wastewater within the reactor. Simultaneously, the introduction of a flow circulation device during the degradation process further ensures more uniform pollutant distribution, increases the probability of reaction with active species, and promotes the diffusion of pollutants on the electrode surface and mass transfer within the system. This significantly improves the degradation rate and efficiency of organohalides. Moreover, this degradation method is economical, feasible, and produces no secondary pollution, and is expected to broaden the scope of practical applications in the electrocatalytic or photo-assisted electrocatalytic degradation of organohalide wastewater.

[0014] Furthermore, the electrocatalytic anode of this invention is a TiO2 nanorod / Ti mesh titanium-based anode (which is anatase phase titanium dioxide), a TiO2 nanocone / Ti mesh titanium-based anode (which is rutile phase titanium dioxide), or a WO3 / W mesh tungsten-based anode (monoclinic phase tungsten trioxide); more preferably, it is a TiO2 nanorod / Ti mesh titanium-based anode. Research results show that, compared with other semiconductor oxides, titanium-based anodes and tungsten-based anodes have better electrocatalytic degradation effects on organic halides in wastewater, especially the TiO2 nanorod / Ti mesh titanium-based anode.

[0015] Furthermore, the electrocatalytic anode described in this invention can be prepared by a hydrothermal method. Specifically, using a metal mesh as a substrate, a nanostructure (nanoringo rods, nanocones, nanosheets) is formed on the substrate surface by controlling the hydrothermal reaction conditions. This method eliminates the need for an external titanium source, resulting in a one-piece molding process, more stable structure, better catalytic degradation effect, and longer service life.

[0016] Specifically, the TiO2 nanorod / Ti mesh titanium-based anode is prepared by the following method:

[0017] (1) The titanium mesh was placed in an alkaline solution for hydrothermal reaction to obtain intermediate product A;

[0018] (2) Immerse intermediate product A in acid solution to obtain intermediate product B;

[0019] (3) The intermediate product B was calcined to obtain TiO2 nanorod / Ti mesh titanium-based material.

[0020] In step (1), the alkali is a commonly used strong alkali, such as sodium hydroxide or potassium hydroxide; the mass concentration of the alkali solution is controlled to be 4-5 mol / L, the temperature of the hydrothermal reaction is 180-230℃, and the time is 2-16 h. This invention etches a titanium mesh substrate under strongly alkaline conditions, providing a basic condition for the growth of TiO2 nanorods. Studies have shown that by rationally controlling the concentration of the alkali solution and the hydrothermal reaction conditions, the morphology of the TiO2 nanorods can be regulated, thereby controlling the size and number of gaps in the three-dimensional network structure formed, which helps to improve the diffusion of pollutants on the electrode surface and the mass transfer within the system, thus improving the degradation rate and degradation efficiency.

[0021] In step (2), the acid is dilute hydrochloric acid; the mass concentration of the acid solution is 0.6–0.7 mol / L, and the soaking time is 0.5–2 h. By reasonably controlling the acid concentration, and thus controlling the appropriate reaction rate, a suitable amount of hydrogen ions (H+) can be obtained. + The metal cations introduced in step (1) are removed by ion exchange to the surface of the prepared electrode, thus preparing for the subsequent TiO2 nanorods.

[0022] In step (3), the calcination conditions are: temperature 400–600℃, time 0.5–4h. By reasonably controlling the above hydrothermal reaction and acid treatment conditions, a high-quality nanorod structure can be formed on the surface of the titanium mesh, which is uniformly distributed and has a better catalytic degradation effect.

[0023] The TiO2 nanocone / Ti mesh titanium-based anode was prepared by the following method:

[0024] (1) Mix tetraisopropoxide titanium and acetylacetone, and dissolve them with EDTA-2Na in deionized water to obtain mixture A;

[0025] (2) Place the titanium mesh in the mixture A and perform a hydrothermal reaction at 180-230℃ for 7-24 hours to obtain intermediate product C;

[0026] (3) The intermediate product C was calcined at 400-600℃ for 0.5-4h to obtain TiO2 nanocone / Ti mesh titanium-based anode.

[0027] The WO3 / W mesh tungsten-based anode is prepared by the following method:

[0028] (1) Mix and dissolve ammonium tungstate and hydrochloric acid in deionized water to form a pale yellow suspension; add 30% hydrogen peroxide solution to the suspension and stir to obtain a clear solution;

[0029] (2) Place the tungsten mesh in the obtained clear solution and perform a hydrothermal reaction at 140-180℃ for 4-15 hours to obtain intermediate product D;

[0030] (3) The intermediate product D is calcined at 400-550℃ for 1-4 hours to obtain WO3 / W mesh tungsten-based anode.

[0031] Furthermore, the electrocatalytic cathode of the present invention is CoMnO. x / GO / graphite felt cathode, which has a layered nanostructure, can be prepared by co-precipitation.

[0032] Specifically, the CoMnO x The / GO / graphite felt cathode is prepared by the following method:

[0033] (1) Manganese nitrate and cobalt nitrate were dissolved in ethanol to obtain a mixed metal solution; then graphene was impregnated in the mixed metal solution and pyrolyzed to obtain a powdered catalyst CoMnO. x / GO;

[0034] (2) The obtained powdered catalyst was mixed with ethanol, Nafion solution (perfluorosulfonic acid polymer solution) and deionized water, then drop-coated onto a graphite felt and dried to obtain CoMnO. x / GO / Graphite Felt Electrocatalytic Cathode.

[0035] In the CoMnO x In the preparation of the / GO / graphite felt cathode, in step (1), the pyrolysis conditions are: treatment under an argon atmosphere at 500-800℃ for 2-5 hours. Studies have shown that by reasonably controlling the pyrolysis conditions, not only is it beneficial to form a CoMnOx solid solution structure, but the catalyst can also be more firmly loaded onto the graphene surface.

[0036] In step (2), the powdered catalyst is mixed with ethanol, Nafion solution and deionized water in a mass-volume ratio of 1 mg: 78-80 uL: 2-3 uL: 20-22 uL.

[0037] In step (2), compared with other substrates, graphite felt has advantages such as good conductivity, large specific surface area, sufficient contact with electrolyte, and more favorable gas-solid-liquid interface diffusion in the reaction system. Using it as a substrate to support powder catalyst can further improve the dispersion of catalyst on the electrode surface, increase the specific surface area of ​​the electrode, expose more reaction sites, and improve the conductivity of the electrode.

[0038] Furthermore, in the electrochemical reaction system, the inlet pipe and outlet pipe are respectively connected to the reactor, the peristaltic pump, and the storage tank; the inlet is at the top of the reactor, and the outlet is at the bottom of the other end of the reactor, ensuring that the wastewater flows through the electrocatalytic anode inside the reactor.

[0039] Furthermore, in the electrochemical reaction system, the electrocatalytic anode and electrocatalytic cathode are supplied with voltage via a DC power supply.

[0040] Furthermore, the electrochemical reaction system also includes a light-assisted system, such as a xenon lamp light source, which irradiates the side of the reactor to achieve photo-assisted electrocatalytic oxidation.

[0041] Secondly, the present invention also provides a method for degrading organohalides in wastewater, comprising: using the above-mentioned electrochemical reaction system to perform electrocatalytic oxidation treatment or photo-assisted electrocatalytic oxidation treatment on the organohalides in wastewater.

[0042] Preferably, the DC power supply provides a voltage range of 0.5 to 5V, and the peristaltic pump rotates at a speed of 20 to 65 rpm (0.5 to 4 mL / min).

[0043] Preferably, the concentration of organohalides in the wastewater does not exceed 5 ppm, for example, 1-5 ppm, which is classified as low-concentration halide wastewater; further, the organohalides are dichloromethane and / or tribromomethane. Studies have shown that the electrochemical reaction system and degradation method described in this invention have better degradation effects on this type of organohalide wastewater.

[0044] The beneficial effects of this invention are as follows:

[0045] This invention designs the electrocatalytic anode or cathode as a mesh structure, enabling uniform diffusion of wastewater within the reactor. Simultaneously, the introduction of a flow circulation device during the degradation process further ensures more even distribution of pollutants, increasing their reaction probability with active species and promoting diffusion of pollutants on the electrode surface and mass transfer within the system. This significantly improves the degradation rate and efficiency of organohalides. Moreover, this degradation method is economical, feasible, and produces no secondary pollution, potentially broadening the scope of practical applications in the electrocatalytic or photo-assisted electrocatalytic degradation of organohalide wastewater. Attached Figure Description

[0046] Figure 1 A schematic diagram of the reaction system designed for photo-assisted electrocatalytic degradation of halide wastewater in Example 1.

[0047] Figure 2 The images show the scanning electron microscope (SEM) and XRD patterns of the TiO2 nanorod / Ti mesh titanium-based anode prepared in Example 2.

[0048] Figure 3 The images show the scanning electron microscope (SEM) and XRD patterns of the TiO2 nanocone / Ti mesh titanium-based anode prepared in Example 3.

[0049] Figure 4 The images show the scanning electron microscope (SEM) and XRD patterns of the WO3 / W mesh tungsten-based anode prepared in Example 4.

[0050] Figure 5 It is the CoMnO prepared in Example 5 x Scanning electron microscope and XRD patterns of graphite felt cathodes.

[0051] Figure 6 Examples 6-13 compare the degradation activity of the reaction system for (photo)electrocatalytic degradation of halide wastewater on the halide dichloromethane and tribromomethane. Detailed Implementation

[0052] The following examples are used to illustrate the present invention, but are not intended to limit the scope of the invention.

[0053] Example 1 Design a flow reaction system for photo-assisted electrocatalytic degradation of halide wastewater.

[0054] This embodiment provides a flow reaction system capable of photo-assisted electrocatalytic degradation of halide wastewater, the structure of which is as follows: Figure 1 As shown.

[0055] The reaction system consists of a reactor, a storage tank, a DC power supply, and a peristaltic pump; a circulation mechanism—the peristaltic pump—connects the reactor and the storage tank.

[0056] The reactor contains a (photo)electrocatalytic anode and / or an electrocatalytic cathode. The electrodes in the reactor are supplied with voltage by a DC power supply, and a xenon lamp light source illuminates the side of the reactor.

[0057] The inlet and outlet pipes are connected to the reactor, peristaltic pump, and storage tank, respectively.

[0058] The inlet is located at the top of the reactor, and the outlet is located at the bottom of the other end of the reactor to ensure that the wastewater flowing into the reactor passes through the electrocatalytic anode.

[0059] The reactor is made entirely of quartz, but is not limited to other translucent materials or combinations of quartz and other materials.

[0060] Example 2 Preparation of TiO2 nanorod / Ti mesh titanium-based anodes

[0061] This embodiment provides the preparation of TiO2 nanorod / Ti mesh titanium-based anodes, including the following steps:

[0062] (1) Place the cleaned titanium mesh in a sodium hydroxide solution and perform a hydrothermal reaction at 200°C for 4 hours.

[0063] (2) Immerse the titanium mesh sample after hydrothermal reaction in dilute hydrochloric acid solution for 1 hour.

[0064] (3) The reacted titanium mesh sample was calcined in a muffle furnace at a temperature of 500℃ for 3 hours to obtain a TiO2 nanorod / Ti mesh titanium-based anode.

[0065] Detection: The electrode prepared in Example 2 was characterized by scanning electron microscopy, see [see details]. Figure 2 It can be seen that... Figure 2 The material exhibits a nanorod-like structure and is evenly distributed.

[0066] The electrode prepared in Example 2 was scanned using an X-ray diffractometer. Figure 2 After comparison with the standard card, it can be confirmed as anatase titanium dioxide.

[0067] Example 3Preparation of TiO2 nanocone / Ti mesh titanium-based anodes

[0068] This embodiment provides the preparation of TiO2 nanocone / Ti mesh titanium-based anodes, including the following steps:

[0069] (1) After mixing tetraisopropoxide titanium and acetylacetone, it is dissolved in deionized water together with EDTA-2Na.

[0070] (2) The above-obtained solution and the cleaned titanium mesh were placed in a hydrothermal reactor and hydrothermally reacted at 200°C for 12 hours.

[0071] (3) The titanium mesh sample after hydrothermal reaction was calcined in a muffle furnace at a temperature of 500℃ for 2 hours to obtain a TiO2 nanocone / Ti mesh titanium-based anode.

[0072] Detection: The electrode prepared in Example 3 was characterized by scanning electron microscopy, see [see details]. Figure 3 It can be seen Figure 3 The material exhibits a nanoconical structure and is vertically distributed on a titanium mesh substrate.

[0073] The electrode prepared in Example 3 was scanned using an X-ray diffractometer. Figure 3 After comparison with the standard card, it can be confirmed as rutile phase titanium dioxide.

[0074] Example 4 Preparation of WO3 / W mesh tungsten-based anodes

[0075] This embodiment provides the preparation of a WO3 / W mesh tungsten-based anode, including the following steps:

[0076] (1) Mix ammonium tungstate and hydrochloric acid and dissolve them in deionized water to form a pale yellow suspension. Add hydrogen peroxide solution to the suspension and stir for 2 hours to obtain a clear solution.

[0077] (2) Place the above-obtained solution and the cleaned tungsten mesh into a hydrothermal reactor and react hydrothermally at 160°C for 12 hours.

[0078] (3) The tungsten mesh sample after hydrothermal reaction was calcined in a muffle furnace at a temperature of 500℃ for 2 hours to obtain a WO3 / W mesh tungsten-based anode.

[0079] Detection: The electrode prepared in Example 4 was characterized by scanning electron microscopy, see [see details]. Figure 4 It can be seen Figure 4 The material exhibits a nanosheet structure, interspersed on a tungsten mesh substrate.

[0080] The electrode prepared in Example 4 was scanned using an X-ray diffractometer. Figure 4After comparison with the standard card, it can be confirmed that it is monoclinic tungsten trioxide, indicating that the WO3 / W mesh tungsten-based anode has been successfully prepared.

[0081] Example 5 Preparation of CoMnO x / GO / Graphite Felt Cathode

[0082] This embodiment provides CoMnO x The preparation of the / GO / graphite felt cathode includes the following steps:

[0083] (1) Manganese nitrate and cobalt nitrate were dissolved in ethanol to obtain a metal mixed solution; then graphene was impregnated in the metal mixed solution and treated under an argon atmosphere at 600℃ for 2 h to obtain the powdered catalyst CoMnO x / GO;

[0084] (2) The powdered catalyst was mixed with ethanol, Nafion solution (perfluorosulfonic acid polymer solution) and deionized water in a mass-volume ratio of 10 mg: 780 uL: 20 uL: 200 uL; after mixing evenly, it was dripped onto graphite felt and dried to obtain the cathode catalyst.

[0085] Detection: The electrode prepared in Example 5 was characterized by scanning electron microscopy, see [see details]. Figure 5 It can be seen Figure 5 The material exhibits a layered nanostructure similar to graphene, resulting in a large specific surface area.

[0086] The electrode prepared in Example 5 was scanned using an X-ray diffractometer. Figure 5 By comparing with the standard card, the characteristic peaks of MnOx and CoOx were found to match, confirming the synthesis of the CoMnOx / GO / graphite felt electrode.

[0087] Example 6 Application of a flow reaction system for electrocatalytic degradation of halide wastewater 1

[0088] This embodiment provides a method for electrocatalytically degrading halide wastewater using the reaction system described in Example 1, the steps of which are as follows:

[0089] (1) Halogenated wastewater simulated with dichloromethane (concentration of 2 ppm) as the target pollutant, and sodium sulfate with an electrolyte of 0.5 mol / L.

[0090] Using the system of Example 1, the TiO2 nanorod / Ti mesh titanium-based anode and graphite sheet of Example 2 were combined as counter electrodes to conduct a dichloromethane degradation experiment.

[0091] (2) Without turning on the xenon lamp light source, the DC power supply provides a voltage range of 2.5V and the peristaltic pump speed of the circulation system is 40rpm.

[0092] (3) The concentration of dichloromethane in the water was measured after 300 min of reaction. The degradation rate was calculated using the following formula: Degradation rate (%) = (1-C t / C0)*100, where Ct is the concentration of the pollutant at time t. The resulting degradation rate is shown in [reference]. Figure 6 .

[0093] Example 7 Application 2 of a flow reaction system for electrocatalytic degradation of halide wastewater

[0094] This embodiment provides a method for electrocatalytically degrading halide wastewater using the reaction system described in Example 1, the steps of which are as follows:

[0095] (1) Halogenated wastewater simulated with dichloromethane (concentration of 2 ppm) as the target pollutant, and sodium sulfate with an electrolyte of 0.5 mol / L.

[0096] Using the system of Example 1, the TiO2 nanocone / Ti mesh titanium-based anode and graphite sheet of Example 3 were combined as counter electrodes to conduct a dichloromethane degradation experiment.

[0097] (2) Without turning on the xenon lamp light source, the DC power supply provides a voltage range of 2.5V and the peristaltic pump speed of the circulation system is 40rpm.

[0098] (3) The concentration of dichloromethane in the water was measured after 300 min of reaction. The degradation rate was calculated using the following formula: Degradation rate (%) = (1-C t / C0)*100, where Ct is the concentration of the pollutant at time t. The resulting degradation rate is shown in [reference]. Figure 6 .

[0099] Example 8 Application of flow reaction system for electrocatalytic degradation of halide wastewater 3

[0100] This embodiment provides a method for electrocatalytically degrading halide wastewater using the reaction system described in Example 1, the steps of which are as follows:

[0101] (1) Halogenated wastewater simulated with dichloromethane (concentration of 2 ppm) as the target pollutant, and sodium sulfate with an electrolyte of 0.5 mol / L.

[0102] Using the system of Example 1, combined with the WO3 / W mesh tungsten-based anode and graphite sheet of Example 4 as counter electrodes, a dichloromethane degradation experiment was conducted.

[0103] (2) Without turning on the xenon lamp light source, the DC power supply provides a voltage range of 2.5V and the peristaltic pump speed of the circulation system is 40rpm.

[0104] (3) The concentration of dichloromethane in the water was measured after 300 min of reaction. The degradation rate was calculated using the following formula: Degradation rate (%) = (1-C t / C0)*100, where Ct is the concentration of the pollutant at time t. The resulting degradation rate is shown in [reference]. Figure 6 .

[0105] Example 9 Application of flow reaction system for electrocatalytic degradation of halide wastewater 4

[0106] This embodiment provides a method for electrocatalytically degrading halide wastewater using the reaction system described in Example 1, the steps of which are as follows:

[0107] (1) Halogenated wastewater simulated with dichloromethane (concentration of 2 ppm) as the target pollutant, and sodium sulfate with an electrolyte of 0.5 mol / L.

[0108] Using the system of Example 1, the CoMnO of Example 5 was combined. x / GO / Graphite felt electrocatalytic cathode and graphite sheet as counter electrode were used in the degradation experiment of dichloromethane.

[0109] (2) Without turning on the xenon lamp light source, the DC power supply provides a voltage range of 2.5V and the peristaltic pump speed of the circulation system is 40rpm.

[0110] (3) The concentration of dichloromethane in the water was measured after 300 min of reaction. The degradation rate was calculated using the following formula: Degradation rate (%) = (1-C t / C0)*100, where Ct is the concentration of the pollutant at time t. The resulting degradation rate is shown in [reference]. Figure 6 .

[0111] Example 10 Application of flow reaction system for electrocatalytic degradation of halide wastewater 5

[0112] This embodiment provides a method for electrocatalytically degrading halide wastewater using the reaction system described in Example 1, the steps of which are as follows:

[0113] (1) Halogenated wastewater simulated with dichloromethane (concentration of 2 ppm) as the target pollutant, and sodium sulfate with an electrolyte of 0.5 mol / L.

[0114] Using the system of Example 1, the TiO2 nanorod / Ti mesh titanium-based anode of Example 2 and the CoMnO of Example 5 were combined. x / GO / Graphite felt electrocatalytic cathode was used as the counter electrode to conduct dichloromethane degradation experiments.

[0115] (2) Without turning on the xenon lamp light source, the DC power supply provides a voltage range of 2.5V and the peristaltic pump speed of the circulation system is 40rpm.

[0116] (3) The concentration of dichloromethane in the water was measured after 300 min of reaction. The degradation rate was calculated using the following formula: Degradation rate (%) = (1-C t / C0)*100, where Ct is the concentration of the pollutant at time t. The resulting degradation rate is shown in [reference]. Figure 6 .

[0117] Example 11 Application of flow reaction system for electrocatalytic degradation of halide wastewater 6

[0118] This embodiment provides a method for electrocatalytically degrading halide wastewater using the reaction system described in Example 1, the steps of which are as follows:

[0119] (1) Halogenated wastewater simulated with tribromomethane (concentration of 5 ppm) as the target pollutant, and sodium sulfate with an electrolyte of 0.5 mol / L.

[0120] Using the system of Example 1, the TiO2 nanorod / Ti mesh titanium-based anode of Example 2 and the CoMnO of Example 5 were combined. x / GO / Graphite felt electrocatalytic cathode was used as the counter electrode to conduct a degradation experiment of tribromomethane.

[0121] (2) Without turning on the xenon lamp light source, the DC power supply provides a voltage range of 2.5V and the peristaltic pump speed of the circulation system is 40rpm.

[0122] (3) The concentration of tribromomethane in the water was measured after 300 min of reaction. The degradation rate was calculated using the following formula: Degradation rate (%) = (1-C t / C0)*100, where Ct is the concentration of the pollutant at time t. The resulting degradation rate is shown in [reference]. Figure 6 .

[0123] Example 12 Application of a flow reaction system for the photocatalytic degradation of halide wastewater 1

[0124] This embodiment provides a method for photo-assisted electrocatalytic degradation of halide wastewater using the reaction system described in Example 1, the steps of which are as follows:

[0125] (1) Halogenated wastewater simulated with dichloromethane (concentration of 2 ppm) as the target pollutant, and sodium sulfate with an electrolyte of 0.5 mol / L.

[0126] Using the system of Example 1, the TiO2 nanorod / Ti mesh titanium-based anode of Example 2 and the CoMnO of Example 5 were combined. x / GO / Graphite felt electrocatalytic cathode was used as the counter electrode to conduct dichloromethane degradation experiments.

[0127] (2) Turn on the xenon lamp light source. The DC power supply provides a voltage range of 2.5V, and the peristaltic pump of the circulation system rotates at 40rpm.

[0128] (3) The concentration of dichloromethane in the water was measured after 300 min of reaction. The degradation rate was calculated using the following formula: Degradation rate (%) = (1-C t / C0)*100, where Ct is the concentration of the pollutant at time t. The resulting degradation rate can be found in [reference needed]. Figure 6 .

[0129] Example 13 Application 2 of a flow reaction system for the photocatalytic degradation of halide wastewater

[0130] This embodiment provides a method for photo-assisted electrocatalytic degradation of halide wastewater using the reaction system described in Example 1, the steps of which are as follows:

[0131] (1) Halogenated wastewater simulated with tribromomethane (concentration of 5 ppm) as the target pollutant, and sodium sulfate with an electrolyte of 0.5 mol / L.

[0132] Using the system of Example 1, the TiO2 nanorod / Ti mesh titanium-based anode of Example 2 and the CoMnO of Example 5 were combined. x / GO / Graphite felt electrocatalytic cathode was used as the counter electrode to conduct a degradation experiment of tribromomethane.

[0133] (2) Turn on the xenon lamp light source. The DC power supply provides a voltage range of 2.5V, and the peristaltic pump of the circulation system rotates at 40rpm.

[0134] (3) The concentration of tribromomethane in the water was measured after 300 min of reaction. The degradation rate was calculated using the following formula: Degradation rate (%) = (1-C t / C0)*100, where Ct is the concentration of the pollutant at time t. The resulting degradation rate is shown in [reference]. Figure 6 .

[0135] Effect verification:

[0136] The results of Examples 6-13 show that the prepared anode catalysts: TiO2 nanorod / Ti mesh titanium-based anode, TiO2 nanocone / Ti mesh titanium-based anode, WO3 / W mesh tungsten-based anode, and cathode catalyst CoMnO x / GO / graphite felt cathodes have excellent catalytic activity and low cost.

[0137] Both electrocatalytic and photo-assisted electrocatalytic systems exhibit advantages such as low energy consumption and high degradation efficiency for halide wastewater.

[0138] This demonstrates that the flow reaction system described in this invention further promotes the diffusion of pollutants on the electrode surface and the mass transfer within the system, thereby increasing the degradation rate of halides. In particular, the flow reaction system for photo-assisted electrocatalytic degradation of halide wastewater exhibits significant degradation effects on halide wastewater, with a simple combined process, economic feasibility, and no secondary pollution.

[0139] Comparative Example 1

[0140] This comparative example provides a method for degrading organic halide wastewater using a conventional electrochemical reaction system. The difference from Example 9 is that the reaction system uses a conventional sheet-like TiO2 nanorod / Ti sheet anode and a graphite sheet cathode without a three-dimensional structure as the counter electrode.

[0141] The results showed that the degradation rate of the halide dichloromethane was only 67.7%; when the halide was replaced with tribromomethane, the degradation rate of tribromomethane was only 14.6%.

[0142] Comparative Example 2

[0143] This comparative example provides a method for degrading organic halide wastewater using an electrochemical reaction system. The difference from Example 9 is that no peristaltic pump is installed in the reaction system.

[0144] The results showed that the degradation rate of the halide dichloromethane was only 89.7%; when the halide was replaced with tribromomethane, the degradation rate of tribromomethane was only 89.0%.

[0145] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. An electrochemical reaction system, comprising: The system comprises a reactor, a storage tank, and a DC power supply; characterized in that the organic halides in the wastewater treated by the electrocatalytic oxidation process are dichloromethane or tribromomethane; the reactor further includes an electrocatalytic anode with a three-dimensional network structure and an electrocatalytic cathode with a three-dimensional cluster structure, the electrocatalytic cathode being CoMnO. x The reactor is a / GO / graphite felt cathode, and the electrocatalytic anode is a TiO2 nanorod / Ti mesh titanium-based anode; a peristaltic pump is connected between the reactor and the storage tank; the electrochemical reaction system is equipped with a light-assisted system. The CoMnO x / GO / Graphite felt cathodes are prepared by the following method: manganese nitrate and cobalt nitrate are dissolved in ethanol to obtain a metal mixed solution; then graphene is impregnated in the metal mixed solution and pyrolyzed to obtain a powdered catalyst CoMnO. x / GO; The obtained powdered catalyst was mixed with ethanol, Nafion solution and deionized water, then drop-coated onto a graphite felt and dried to obtain CoMnO. x / GO / graphite felt electrocatalytic cathode; the pyrolysis conditions are: treatment under an argon atmosphere at 500-800℃ for 2-5 hours.

2. The electrochemical reaction system according to claim 1, characterized in that, The TiO2 nanorod / Ti mesh titanium-based anode was prepared by the following method: (1) The titanium mesh was placed in an alkaline solution for hydrothermal reaction to obtain intermediate product A; (2) Immerse intermediate product A in acid solution to obtain intermediate product B; (3) The intermediate product B was calcined to obtain TiO2 nanorod / Ti mesh titanium-based material.

3. The electrochemical reaction system according to claim 2, characterized in that, In step (1), the mass concentration of the alkaline solution is controlled to be 4-5 mol / L, the temperature of the hydrothermal reaction is 180-230℃, and the time is 2-16h.

4. The electrochemical reaction system according to claim 3, characterized in that, In step (2), the acid is dilute hydrochloric acid; the mass concentration of the acid solution is 0.6-0.7 mol / L; and the soaking time is 0.5-2 h.

5. A method for degrading organohalides in wastewater, characterized in that, The electrochemical reaction system according to any one of claims 1 to 4 is used to perform electrocatalytic oxidation treatment of organic halides in wastewater, or the electrochemical reaction system according to any one of claims 1 to 4 is used to perform photo-assisted electrocatalytic oxidation treatment of organic halides in wastewater.

6. The method according to claim 5, characterized in that, The DC power supply provides a voltage range of 0.5 to 5V, and the peristaltic pump speed is 20 to 65 rpm.

7. The method according to claim 6, characterized in that, The concentration of organic halides in the wastewater does not exceed 5 ppm.

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