Method for electrochemically simultaneously removing heavy metal complex and halogenated organic compound in industrial wastewater by using activated carbon fiber

Abstract

The application discloses a method for electrochemically synchronously removing heavy metal complex and halogenated organic compounds in industrial wastewater by using activated carbon fiber, which comprises the following steps: firstly, activating the carbon fiber, taking the activated carbon fiber as the electrode of a single-chamber electrochemical reaction device, applying voltage, stirring the industrial wastewater containing heavy metal complex and halogenated organic compounds, and reducing and recycling the heavy metal complex while reducing and dehalogenating the halogenated organic compounds, so as to finally realize the removal of the heavy metal complex and the halogenated organic compounds. The electrochemical method can be used to completely dehalogenate the halogenated organic compounds in a short time, to highly mineralize the macromolecular heavy metal complex in water, and to recycle the heavy metal in water. The method is simple, convenient, easy to realize and cost-saving.

Description

Technical Field

[0001] This invention belongs to the field of industrial wastewater treatment and relates to a method for the simultaneous removal of heavy metal complexes and halogenated organic compounds from wastewater. Specifically, it relates to a method for the electrochemical removal of pollutants from industrial wastewater using activated carbon fiber electrodes, particularly a method that utilizes the synergistic oxidation-reduction reaction on the surface of activated carbon fiber electrodes to simultaneously remove heavy metal complexes and halogenated organic compounds from wastewater. This is a green industrial wastewater treatment technology. Background Technology

[0002] In recent years, improper treatment and indiscriminate discharge of industrial wastewater have become one of the main sources of water pollution. Due to different production processes, industrial wastewater may contain various heavy metal complexes and halogenated organic compounds. Complexing agents have a high affinity for heavy metal ions, and the resulting heavy metal complexes are highly water-soluble, making conventional coagulation-precipitation processes ineffective. Because heavy metal complexes are biotoxic, traditional biological methods are ineffective at removing them. Halogenated organic compounds have carcinogenic, teratogenic, and mutagenic effects on humans, and long-term exposure can damage the nervous and reproductive systems. Many halogenated organic compounds have been listed as "priority controlled compounds" by numerous countries worldwide. my country's "Groundwater Quality Standard" (GB / T14848-2017), issued in 2018, added several halogenated organic pollutants to its list. Halogenated organic compounds (HOCs) are characterized by high toxicity, structural stability, strong migration ability, and poor biodegradability. Conventional physical (air stripping, adsorption, thermal treatment), biological (aerobic oxidation dehalogenation, anaerobic reduction dehalogenation), and chemical (direct oxidation, reduction) processes are ineffective in treating them, and volatile organic compounds pose a risk of secondary pollution. Furthermore, to save costs, factories often mix wastewater containing heavy metal complexes with wastewater containing HOCs, significantly increasing the difficulty of wastewater treatment.

[0003] Chemical treatment can remove pollutants by destroying the molecular structure of heavy metal complexes and halogenated organic compounds through oxidation and reduction pathways. In recent years, advanced oxidation systems (AOS) have been widely used in industrial wastewater treatment due to their high degradation efficiency and low investment cost. AOS systems catalyze the generation of free radicals with strong oxidizing power to attack organic pollutant molecules, thereby degrading them. However, the degradation of heavy metal complexes in AOS systems may lead to the release of heavy metal ions, and halogenated organic compounds may be degraded into more toxic halogenated intermediates, causing secondary pollution. Advanced reduction systems exhibit strong reductive dehalogenation capabilities for halogenated organic compounds, acting on carbon-halogen bonds through direct or indirect electron transfer. However, AOS systems are less effective at destroying the molecular structure of heavy metal complexes; once the electron donors in the system are depleted, the reduction rate of halogenated organic compounds decreases significantly.

[0004] Currently, there is a lack of effective methods to simultaneously remove heavy metal complexes and halogenated organic compounds from industrial wastewater. Summary of the Invention

[0005] In order to solve the problems of the prior art, the purpose of this invention is to overcome the shortcomings of the existing technology and provide a method for the simultaneous electrochemical removal of heavy metal complexes and halogenated organic compounds from industrial wastewater using activated carbon fibers, which can be used for industrial wastewater treatment to achieve efficient and harmless removal of heavy metal complexes and halogenated organic compounds.

[0006] The technical solution provided by this invention is as follows:

[0007] A method for the simultaneous electrochemical removal of heavy metal complexes and halogenated organic compounds from industrial wastewater using activated carbon fibers, characterized by comprising the following steps:

[0008] Step 1: Activate carbon fibers;

[0009] Step 2: Use activated carbon fibers as electrodes in a single-chamber electrochemical reaction device;

[0010] Step 3: Inject industrial wastewater containing heavy metal complexes and halogenated organic compounds into the electrochemical reaction device, start stirring, and apply a potential to the electrodes to simultaneously remove heavy metal complexes and halogenated organic compounds from the industrial wastewater.

[0011] Furthermore, in step 1, the method for activating carbon fiber is as follows: immerse the carbon fiber in an acid solution under an oxygen-free environment, and then clean and dry it to obtain the final product.

[0012] Furthermore, concentrated nitric acid is used in the acid washing and activation process of the carbon fiber electrode.

[0013] Furthermore, the carbon fiber electrode is plate-shaped.

[0014] Furthermore, in step 2, the electrode also includes a reference electrode.

[0015] Furthermore, in the heavy metal complex, the metal ions include any one or a combination of several of Co, Ni, Cu, Fe, and Pd ions, and the ligands include any one or a combination of several of ethanolamine, diethanolamine, triethanolamine, ethylenediaminetetraacetic acid, and citric acid. Preferably, the metal ions include Co(II), Ni(II), Cu(II), Fe(II), and Pd(II) ions.

[0016] Furthermore, the halogenated organic compounds include C1-C6 alkanes, C2-C6 alkenes, and C6-C6 alkenes. 12 Aryl halogenated compounds.

[0017] Furthermore, the halogenated organic compounds include C1-C6 alkanes, C2-C6 alkenes, and C1-C4 alkyl-substituted phenyl compounds, wherein the halogen of the halogenated compounds is F, Cl, Br, or I. Preferably, the halogenated organic compounds include halogenated compounds of methane, ethyl hydrocarbons, propane, butane, ethylene, propylene, butene, butadiene, and phenyl, wherein the halogen of the halogenated compounds is F, Cl, or Br. More preferably, the halogenated organic compounds in the industrial wastewater are one or more of the following organic compounds: trichloroethylene, tetrachloromethane, chloroform, trichloroethane, and trichlorobenzene.

[0018] Furthermore, the concentration of heavy metal complexes in the industrial wastewater shall not be less than 10 mM.

[0019] Furthermore, both the cathode and anode are activated carbon fibers, and the reaction apparatus is energized with direct current. Preferably, a reduction potential is applied to the electrodes, which is a potential capable of initiating a complex-breaking reaction, reducing metal ions, and catalyzing the production of atomic hydrogen. This potential is measured by a reference electrode, and the actual voltage can be monitored using a multimeter. More preferably, the reduction potential ranges from -1V to -2V.

[0020] Furthermore, if the salinity of the industrial wastewater is low, an electrolyte can be added to adjust it. Preferably, the electrolyte is sodium sulfate.

[0021] Furthermore, when the concentration of pollutants in the wastewater is low or the pollutants are non-volatile substances, the top of the device does not need to be sealed; when the concentration of pollutants in the wastewater is high or the wastewater contains volatile substances, the top of the device needs to be connected to a gas recovery device.

[0022] Furthermore, the carbon fiber electrode can be recycled and reused after use.

[0023] Furthermore, in step 3, the carbon fiber electrode in the electrochemical reaction device is vertically suspended at the top of the reaction device, and the water level in the reaction device should be submerged at the top of the electrode.

[0024] Furthermore, in step 3, the stirring rate of the solution inside the electrochemical device is not less than 500 rpm.

[0025] Furthermore, carbon fiber activation and acid washing and recycling of used carbon fiber electrodes are carried out in an oxygen-free glove box, while electrode assembly and electrochemical treatment of industrial wastewater are carried out under air conditions.

[0026] Furthermore, in step 3, industrial wastewater is introduced into the reactor in a sequencing batch process, and solid particulate matter in the wastewater needs to be removed before electrochemical treatment.

[0027] This invention utilizes the metal atoms of heavy metal complexes in industrial wastewater as electron donors and acceptors in redox reactions. Through electrochemical means, it acts on the redox dehalogenation of halogenated organic compounds, thereby simultaneously removing heavy metal complexes and halogenated organic compounds from industrial wastewater. This method aligns with the environmental protection concept of "treating waste with waste," has potential application value, and can provide a new approach to current industrial wastewater treatment.

[0028] The principle of this invention is as follows:

[0029] This invention first applies a reduction potential to an activated carbon fiber electrode. Heavy metal complexes in the solution migrate to the surface of the carbon fiber electrode and gain electrons. The metal-complex groups of the heavy metal complexes are then destroyed, resulting in a complex-breaking reaction. Next, the released heavy metal ions gain electrons on the activated carbon fiber surface and are reduced to zero-valent metals. Under the influence of the reduction potential, the zero-valent metals catalyze the production of atomic hydrogen from protonated hydrogen or water, which has strong reducing power. This atomic hydrogen attacks the carbon-halogen bonds of halogenated organic compounds, causing reductive dehalogenation. Subsequently, the atomic hydrogen reacts with oxygen generated at the anode to produce hydrogen peroxide. This hydrogen peroxide is further activated by atomic hydrogen to generate highly oxidizing hydroxyl radicals. The large organic molecules released after the heavy metal complexes are broken down are efficiently mineralized into inorganic substances under the attack of these hydroxyl radicals. Finally, heavy metal ions in the wastewater are adsorbed and recovered by the activated carbon fiber electrode, halogenated organic compounds are efficiently dehalogenated and degraded, and large organic pollutants are mineralized and removed. This invention features a simple, green, and low-carbon operation process, offering significant environmental and economic benefits.

[0030] The beneficial effects of this invention are as follows:

[0031] 1. The method of this invention can fully utilize activated carbon fiber materials and combine electrochemical reduction-complex breaking-oxidation methods to efficiently remove heavy metal complexes and halogenated organic compounds from industrial wastewater, achieving the goal of "treating waste with waste" and has potential application value. It constructs an electrochemical synergistic "reduction-oxidation" system, utilizing the high specific surface area and strong electrical conductivity of carbon fiber to convert heavy metal complexes in industrial wastewater into zero-valent metals. Then, by utilizing the catalytic ability of active hydrogen substances such as Co, Ni, Cu, Fe, and Pd, halogenated organic compounds in industrial wastewater are further removed, achieving efficient and harmless treatment of industrial wastewater, reducing the risk of secondary pollution, and providing a new approach for the current deep treatment of industrial wastewater.

[0032] 2. The method of the present invention utilizes activated carbon fiber electrodes to "reduce-break" heavy metal complexes to generate zero-valent metal active sites. Then, through electron transfer, the zero-valent metal active sites catalyze proton hydrogen and water to generate atomic hydrogen. The atomic hydrogen activates molecular oxygen to generate hydroxyl radicals, forming a "reduction-oxidation" synergistic system. This system can completely dehalogenate halogenated organic compounds in a short time and has a high-efficiency mineralization ability for macromolecular organic compounds in the system.

[0033] 3. The method of the present invention does not require the addition of other oxidants or reducing agents, is simple to operate, cost-effective, easy to implement, has no risk of secondary pollution, and is safe and environmentally friendly. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the electrochemical process for the simultaneous removal of heavy metal complexes and halogenated organic compounds from industrial wastewater according to the present invention.

[0035] Figure 2 This is a schematic diagram of the electrochemical device of the present invention.

[0036] Figure 3 This is a diagram showing the pollutant removal effect of the present invention.

[0037] Figure 4 The images show the XRD patterns before and after the electrode reaction of this invention.

[0038] Figure 5 This is a diagram showing the capture of active substances in the system of this invention. Detailed Implementation

[0039] The above solution will be further described below with reference to specific embodiments. The preferred embodiments of the present invention are described in detail below:

[0040] See Figure 1 This invention provides a method for the simultaneous electrochemical removal of heavy metal complexes and halogenated organic compounds from industrial wastewater using activated carbon fibers. The method utilizes an activated carbon fiber electrode electrochemical system to synergistically remove heavy metal complexes and halogenated organic compounds through a "reduction-oxidation" process. Under the influence of a reduction potential, the activated carbon fiber electrode reduces and breaks down the heavy metal complexes, converting heavy metal ions into zero-valent metals on the surface of the activated carbon fibers. These zero-valent metals, under the influence of the reduction potential, catalyze the generation of atomic hydrogen from protonated hydrogen or water, which has strong reducing power. This atomic hydrogen attacks the carbon-halogen bonds of the halogenated organic compounds, causing reductive dehalogenation. The atomic hydrogen reacts with oxygen generated at the anode to produce hydrogen peroxide. This hydrogen peroxide is further activated by atomic hydrogen to generate highly oxidizing hydroxyl radicals. The large organic molecules released after the heavy metal complexes are broken down are efficiently mineralized into inorganic substances under the attack of these hydroxyl radicals. The system is sampled and tested at different reaction times. The specific steps are as follows:

[0041] (1) Immerse the carbon fiber in an acid solution in an oxygen-free environment for 24 hours, then remove it and wash it with oxygen-free ultrapure water until the pH of the washing solution is neutral. Air dry it in an oxygen-free environment for later use.

[0042] (2) Cut the air-dried carbon fiber to a suitable size and use it as an electrode for a single-chamber electrochemical reaction device for later use.

[0043] (3) Inject industrial wastewater containing heavy metal complexes and halogenated organic compounds into an electrochemical reaction device, turn on the stirring, and apply a reduction potential to the activated carbon fiber electrode to complete the simultaneous removal of heavy metal complexes and halogenated organic compounds from the industrial wastewater.

[0044] As a preferred technical solution of the present invention, the heavy metal complex includes any one or a combination of several of the following metal ions: Co(II), Ni(II), Cu(II), Fe(II), and Pd(II); and the ligand includes any one or a combination of several of the following ethanolamine (ETA), diethanolamine (DTA), triethanolamine (TEA), ethylenediaminetetraacetic acid (EDTA), and citric acid (CA).

[0045] As a preferred embodiment of the present invention, the halogenated organic compounds include C1-C6 alkanes, C2-C6 alkenes, and C6-C6 alkenes. 12 Aryl halogenated compounds. Further, the halogenated organic compounds include C1-C6 alkanes, C2-C6 alkenes, and C1-C4 alkyl-substituted phenyl compounds. Preferably, the halogenated organic compounds include halogenated compounds of methane, ethyl hydrocarbons, propane, butane, ethylene, propylene, butene, butadiene, and phenyl. More preferably, the halogenated organic compounds in the industrial wastewater are one or more of trichloroethylene, tetrachloromethane, chloroform, trichloroethane, and trichlorobenzene.

[0046] As a preferred technical solution of the present invention, in steps (1) and (2), the concentration of heavy metal complexes in the industrial wastewater shall not be less than 10 mM.

[0047] As a preferred technical solution of the present invention, in step (2), the electrode further includes a reference electrode.

[0048] As a preferred technical solution of the present invention, in step (3), both the anode and the cathode are activated carbon fiber electrodes. Figure 2 A DC voltage is applied to the reaction apparatus. Preferably, a reduction potential is applied to the electrodes, and a potential of -1V to -2V is applied as the reference electrode to measure the potential. The actual voltage can be monitored by a multimeter.

[0049] As a preferred technical solution of the present invention, in step (3), the carbon fiber electrode in the electrochemical reaction device is vertically suspended at the top of the reaction device, and the water level in the reaction device should be submerged at the top of the electrode.

[0050] As a preferred technical solution of the present invention, in step (3), the stirring rate of the solution in the electrochemical device is not less than 500 rpm.

[0051] As a preferred technical solution of the present invention, the carbon fiber electrode can be recycled and reused after use.

[0052] As a preferred technical solution of the present invention, after electrochemical treatment, the carbon fiber electrode is recovered, the carbon fiber is soaked in an acid solution for 24 hours, then washed with oxygen-free ultrapure water until the pH of the washing solution is neutral, and then air-dried in an oxygen-free environment for reuse.

[0053] As a preferred technical solution of the present invention, concentrated nitric acid is used in the pickling and activation process.

[0054] As a preferred embodiment of the present invention, the carbon fiber activation and the acid washing and recycling of the carbon fiber electrode after use are carried out in an oxygen-free glove box, while the electrode assembly and the electrochemical treatment of industrial wastewater are carried out under air conditions.

[0055] As a preferred embodiment of the present invention, if the salinity of the industrial wastewater is low, an electrolyte can be added appropriately to adjust it. Preferably, the electrolyte is 2mM sodium sulfate electrolyte.

[0056] As a preferred technical solution of the present invention, when the concentration of pollutants in the wastewater is low or the pollutants are non-volatile substances, the top of the device does not need to be sealed; when the concentration of pollutants in the wastewater is high or the wastewater contains volatile substances, the top of the device needs to be connected to a gas recovery device.

[0057] As a preferred technical solution of the present invention, in step 3, industrial wastewater is introduced into the reactor in a sequential batch manner, and solid particulate matter in the wastewater needs to be removed before electrochemical treatment.

[0058] Example 1

[0059] In this embodiment, a method for the simultaneous electrochemical removal of Ni-EDTA and trichloroethylene from industrial wastewater using activated carbon fibers, wherein the trichloroethylene concentration is 25 μM, includes the following steps:

[0060] In an oxygen-free glove box, carbon fiber is immersed in concentrated nitric acid solution for one day. After immersion, it is taken out and rinsed with oxygen-free ultrapure water until the pH of the rinsing solution is neutral. After air drying, it is ready for use.

[0061] Take the activated carbon fiber from the oxygen-free glove box, cut it (2cm×2cm), install the activated carbon fiber in a 50mL capacity single-chamber electrochemical reaction device as the anode and cathode, and install the Ag / AgCl reference electrode for later use.

[0062] A pollutant solution containing Ni-EDTA and trichloroethylene was injected into the electrochemical device. The Ni-EDTA was prepared by mixing NiSO4 and Na2EDTA at equal concentrations. The volume of the pollutant solution was 30 mL, and the Ni-EDTA concentration was 10 mM. Magnetic stirring was started at a stirring speed of 500 rpm, and a potential of -2.0 V was applied to the working electrode. After 5 hours of reaction, the removal rates of both Ni-EDTA and trichloroethylene reached 100%, the total Ni removal rate reached 99.3%, and the total organic carbon removal rate reached 90.6%. Figure 3 ).

[0063] This embodiment of the method can fully utilize activated carbon fiber for the simultaneous electrochemical removal of Ni-EDTA and trichloroethylene from industrial wastewater. Ni-EDTA undergoes a reduction-complex breaking reaction on the surface of the activated carbon fiber electrode to transform into zero-valent Ni (Ni(EDTA)). Figure 4 Zero-valent Ni active sites catalyze the generation of atomic hydrogen through electron transfer. This atomic hydrogen attacks the carbon-chlorine bonds of trichloroethylene, causing its reduction and dechlorination. The atomic hydrogen then activates molecular oxygen to generate hydroxyl radicals, which attack and mineralize large organic molecules. Figure 5 This allows for the efficient and simultaneous removal of Ni-EDTA and trichloroethylene from industrial wastewater, resulting in significant environmental and economic benefits.

[0064] Example 2

[0065] In this embodiment, a method for the simultaneous electrochemical removal of Cu-DTA and tetrachloromethane from industrial wastewater using activated carbon fibers, wherein the tetrachloromethane concentration is 25 μM, includes the following steps:

[0066] In an oxygen-free glove box, carbon fiber is immersed in concentrated nitric acid solution for one day. After immersion, it is taken out and rinsed with oxygen-free ultrapure water until the pH of the rinsing solution is neutral. After air drying, it is ready for use.

[0067] Take the activated carbon fiber from the oxygen-free glove box, cut it (2cm×2cm), install the activated carbon fiber in a 50mL capacity single-chamber electrochemical reaction device as the anode and cathode, and install the Ag / AgCl reference electrode for later use.

[0068] A contaminated solution containing Cu-DTA and tetrachloromethane was injected into the electrochemical device. The Cu-DTA was prepared by equal concentrations of CuSO4 and Na2DTA. The volume of the contaminated solution was 30 mL, and the concentration of Cu-DTA was 10 mM. Magnetic stirring was turned on at a stirring speed of 500 rpm. A potential of -2.0 V was applied to the working electrode. After 5 hours of reaction, the removal rates of both Cu-DTA and tetrachloromethane reached 100%, the total Cu removal rate reached 98.7%, and the total organic carbon removal rate reached 82.2%.

[0069] The method in this embodiment can fully utilize activated carbon fiber to electrochemically and simultaneously remove Cu-DTA and tetrachloromethane from industrial wastewater. Cu-DTA undergoes a reduction-complex breaking reaction on the surface of the activated carbon fiber electrode to convert into zero-valent Cu. The active sites of zero-valent Cu catalyze the generation of atomic hydrogen through electron transfer. The atomic hydrogen attacks the carbon-chlorine bonds of tetrachloromethane, causing it to be reduced and dechlorinated. The atomic hydrogen then activates molecular oxygen to generate hydroxyl radicals, which attack and mineralize large organic molecules, thereby achieving efficient and simultaneous removal of Cu-DTA and tetrachloromethane from industrial wastewater, with good environmental and economic benefits.

[0070] Example 3

[0071] In this embodiment, a method for the simultaneous electrochemical removal of Fe-CA and chloroform from industrial wastewater using activated carbon fibers, wherein the chloroform concentration is 25 μM, includes the following steps:

[0072] In an oxygen-free glove box, carbon fiber is immersed in concentrated nitric acid solution for one day. After immersion, it is taken out and rinsed with oxygen-free ultrapure water until the pH of the rinsing solution is neutral. After air drying, it is ready for use.

[0073] Take the activated carbon fiber from the oxygen-free glove box, cut it (2cm×2cm), install the activated carbon fiber in a 50mL capacity single-chamber electrochemical reaction device as the anode and cathode, and install the Ag / AgCl reference electrode for later use.

[0074] A pollutant solution containing Fe-CA and chloroform was injected into the electrochemical device. The Fe-CA solution was prepared by equal concentrations of FeSO4 and Na3CA. The volume of the pollutant solution was 30 mL, and the concentration of Fe-CA was 10 mM. Magnetic stirring was turned on at a stirring speed of 500 rpm. A potential of -2.0 V was applied to the working electrode. After 5 hours of reaction, the removal rates of Fe-CA and chloroform were both 100%, the total Fe removal rate was 99.7%, and the total organic carbon removal rate was 88.4%.

[0075] The method in this embodiment can fully utilize activated carbon fiber to electrochemically and simultaneously remove Fe-CA and chloroform from industrial wastewater. Fe-CA undergoes a reduction-complex breaking reaction on the surface of the activated carbon fiber electrode to convert into zero-valent Fe. The active sites of zero-valent Fe catalyze the generation of atomic hydrogen through electron transfer. The atomic hydrogen attacks the carbon-chlorine bonds of chloroform, causing it to be reduced and dechlorinated. The atomic hydrogen then activates molecular oxygen to generate hydroxyl radicals, which attack and mineralize large organic molecules, thereby achieving efficient and simultaneous removal of Fe-CA and chloroform from industrial wastewater, with good environmental and economic benefits.

[0076] Example 4

[0077] In this embodiment, a method for the simultaneous electrochemical removal of Co-TEA and trichlorobenzene from industrial wastewater using activated carbon fibers, wherein the trichlorobenzene concentration is 25 μM, includes the following steps:

[0078] In an oxygen-free glove box, carbon fiber is immersed in concentrated nitric acid solution for one day. After immersion, it is taken out and rinsed with oxygen-free ultrapure water until the pH of the rinsing solution is neutral. After air drying, it is ready for use.

[0079] Take the activated carbon fiber from the oxygen-free glove box, cut it (2cm×2cm), install the activated carbon fiber in a 50mL capacity single-chamber electrochemical reaction device as the anode and cathode, and install the Ag / AgCl reference electrode for later use.

[0080] A pollutant solution containing Co-TEA and trichlorobenzene was injected into the electrochemical device. The Co-TEA was prepared by equal concentrations of CoSO4 and Na3TEA. The volume of the pollutant solution was 30 mL, and the concentration of Co-TEA was 10 mM. Magnetic stirring was turned on at a stirring speed of 500 rpm. A potential of -2.0 V was applied to the working electrode. After 5 hours of reaction, the removal rates of both Co-TEA and trichlorobenzene reached 100%, the total Co removal rate reached 96.8%, and the total organic carbon removal rate reached 75.2%.

[0081] The method in this embodiment can fully utilize activated carbon fiber to electrochemically remove Co-TEA and trichlorobenzene from industrial wastewater simultaneously. Co-TEA undergoes a reduction-complex breaking reaction on the surface of the activated carbon fiber electrode to convert into zero-valent Co. The active sites of zero-valent Co catalyze the generation of atomic hydrogen through electron transfer. The atomic hydrogen attacks the carbon-chlorine bonds of trichlorobenzene, causing it to be reduced and dechlorinated. The atomic hydrogen then activates molecular oxygen to generate hydroxyl radicals, which attack and mineralize large organic molecules, thereby achieving efficient and simultaneous removal of Co-TEA and trichlorobenzene from industrial wastewater, with good environmental and economic benefits.

[0082] Example 5

[0083] In this embodiment, a method for the simultaneous electrochemical removal of Pd-ETA and trichloroethane from industrial wastewater using activated carbon fibers, wherein the trichloroethane concentration is 25 μM, includes the following steps:

[0084] In an oxygen-free glove box, carbon fiber is immersed in concentrated nitric acid solution for one day. After immersion, it is taken out and rinsed with oxygen-free ultrapure water until the pH of the rinsing solution is neutral. After air drying, it is ready for use.

[0085] Take the activated carbon fiber from the oxygen-free glove box, cut it (2cm×2cm), install the activated carbon fiber in a 50mL capacity single-chamber electrochemical reaction device as the anode and cathode, and install the Ag / AgCl reference electrode for later use.

[0086] A pollutant solution containing Pd-ETA and trichloroethane was injected into the electrochemical device. The Pd-ETA was prepared by mixing PdCl2 and ETA at equal concentrations. The volume of the pollutant solution was 30 mL, and the concentration of Pd-ETA was 10 mM. Magnetic stirring was turned on at a stirring speed of 500 rpm. A potential of -2.0 V was applied to the working electrode. After 5 hours of reaction, the removal rates of both Pd-ETA and trichloroethane reached 100%, the total Pd removal rate reached 99.9%, and the total organic carbon removal rate reached 98.1%.

[0087] The method in this embodiment can fully utilize activated carbon fiber to electrochemically and simultaneously remove Pd-ETA and trichloroethane from industrial wastewater. Pd-ETA undergoes a reduction-complex breaking reaction on the surface of the activated carbon fiber electrode to convert into zero-valent Pd. The active sites of zero-valent Pd catalyze the generation of atomic hydrogen through electron transfer. The atomic hydrogen attacks the carbon-chlorine bonds of trichloroethane, causing it to be reduced and dechlorinated. The atomic hydrogen then activates molecular oxygen to generate hydroxyl radicals, which attack and mineralize large organic molecules. This achieves efficient and simultaneous removal of Pd-ETA and trichloroethane from industrial wastewater, resulting in good environmental and economic benefits.

[0088] The embodiments of the present invention have been described above in conjunction with the accompanying drawings. However, the present invention is not limited to the above embodiments. Various changes can be made according to the purpose of the invention. Any changes, modifications, substitutions, combinations or simplifications made based on the spirit and principle of the technical solution of the present invention shall be equivalent substitutions. As long as they meet the purpose of the invention and do not deviate from the technical principle and inventive concept of the present invention for the simultaneous electrochemical removal of heavy metal complexes and halogenated organic compounds from industrial wastewater using activated carbon fibers, they shall fall within the protection scope of the present invention.

Claims

1. A method for the simultaneous electrochemical removal of heavy metal complexes and halogenated organic compounds from industrial wastewater using activated carbon fibers, characterized in that... Includes the following steps: Step 1: Activate carbon fibers; Step 2: Use activated carbon fibers as electrodes in a single-chamber electrochemical reaction device; Step 3: Inject industrial wastewater containing heavy metal complexes and halogenated organic compounds into the electrochemical reaction device, start stirring, and apply a potential to the electrodes to simultaneously remove heavy metal complexes and halogenated organic compounds from the industrial wastewater.

2. The method for simultaneous electrochemical removal of heavy metal complexes and halogenated organic compounds from industrial wastewater using activated carbon fibers according to claim 1, characterized in that: In step 1, the carbon fiber is activated as follows: the carbon fiber is immersed in an acid solution in an oxygen-free environment, and then washed and dried.

3. The method for simultaneous electrochemical removal of heavy metal complexes and halogenated organic compounds from industrial wastewater using activated carbon fibers according to claim 1, characterized in that: In step 2, the electrode also includes a reference electrode.

4. The method for simultaneous electrochemical removal of heavy metal complexes and halogenated organic compounds from industrial wastewater using activated carbon fibers according to claim 1, characterized in that: The heavy metal complex includes metal ions such as any one or a combination of Co, Ni, Cu, Fe, and Pd ions, and ligands such as any one or a combination of ethanolamine, diethanolamine, triethanolamine, ethylenediaminetetraacetic acid, and citric acid.

5. The method for simultaneous electrochemical removal of heavy metal complexes and halogenated organic compounds from industrial wastewater using activated carbon fibers according to claim 1, characterized in that: The halogenated organic compounds include C1-C6 alkanes, C2-C6 alkenes, and C6-C6 alkenes. 12 Aryl halogenated compounds.

6. The method for simultaneous electrochemical removal of heavy metal complexes and halogenated organic compounds from industrial wastewater using activated carbon fibers according to claim 1, characterized in that: The concentration of heavy metal complexes in the industrial wastewater shall not be less than 10 mM.

7. The method for simultaneous electrochemical removal of heavy metal complexes and halogenated organic compounds from industrial wastewater using activated carbon fibers according to claim 1, characterized in that: Both the cathode and anode are activated carbon fibers, and the reaction device is powered by direct current.

8. The method for simultaneous electrochemical removal of heavy metal complexes and halogenated organic compounds from industrial wastewater using activated carbon fibers according to claim 1, characterized in that: If the salinity of industrial wastewater is low, add electrolytes to adjust it.

9. The method for simultaneous electrochemical removal of heavy metal complexes and halogenated organic compounds from industrial wastewater using activated carbon fibers according to claim 1, characterized in that: When the concentration of pollutants in the wastewater is low or the pollutants are non-volatile substances, the top of the device does not need to be sealed; when the concentration of pollutants in the wastewater is high or the wastewater contains volatile substances, the top of the device needs to be connected to a gas recovery device.

10. The method for simultaneous electrochemical removal of heavy metal complexes and halogenated organic compounds from industrial wastewater using activated carbon fibers according to claim 1, characterized in that: The carbon fiber electrode is recycled and reused after use.

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