A double-chamber decoupling water treatment method and device based on a graphite blanket loaded cobalt-manganese oxide composite material

Abstract

The present application relates to the technical field of water treatment, in particular to a double-chamber decoupling water treatment method and device based on graphite blanket loaded cobalt manganese oxide composite material. The present application uses graphite blanket as carrier to deposit loaded cobalt manganese oxide in situ, and uses the material to construct double-chamber decoupling water treatment device. The cathode chamber and the anode chamber of the double-chamber decoupling water treatment device are separated by proton exchange membrane, the anode electrode uses graphite blanket loaded cobalt manganese oxide composite material, the cathode electrode uses graphite blanket loaded carbon nanotube composite material, the cathode electrode and the anode electrode are connected through wires, under the premise that the oxidant does not directly contact with the water body to be treated, the pollutants are oxidized and gathered through the decoupling water treatment method, the polymerization product is formed, the polymerization product is adsorbed on the surface of the composite material to realize efficient separation, and the deep removal of pollutants and total organic carbon is simultaneously achieved. The present application significantly reduces the consumption of oxidant, avoids the risk of increasing the salinity of effluent and residual intermediate product.

Description

Technical Field

[0001] This invention relates to the field of water treatment technology, and specifically to a dual-chamber decoupled water treatment method and apparatus based on a graphite blanket-loaded cobalt-manganese oxide composite material. Background Technology

[0002] Emerging pollutants are a class of chemical or biological pollutants that have been recently discovered or are of ongoing concern in the environment. These pollutants are not yet included in routine environmental monitoring and management systems, but they pose significant potential risks to the ecological environment and human health. They are characterized by their high degree of concealment, making them difficult to identify in the natural environment through conventional detection methods. Furthermore, they exhibit remarkable environmental persistence, remaining in various environmental media such as water, soil, and air for extended periods without significant degradation. Simultaneously, emerging pollutants demonstrate significant bioaccumulation, accumulating and amplifying through the food chain, ultimately posing a serious threat to higher trophic levels of organisms and even human health. Their harmful mechanisms are complex and diverse, potentially triggering a series of adverse effects such as genotoxicity, endocrine disruption, carcinogenicity, and teratogenicity. Because traditional wastewater treatment facilities are primarily designed for conventional pollutants and lack efficient removal mechanisms for emerging pollutants, these pollutants often enter the ecosystem through wastewater treatment plant effluent and sludge disposal, widely spreading and accumulating in various environmental media and organisms, becoming a critical issue that urgently needs to be addressed in the field of environmental protection.

[0003] Advanced oxidation processes (AEs), as one of the most promising advanced water treatment technologies, work by generating highly reactive oxygen species (ROS) in situ within the reaction system. These ROS utilize their high reactivity to oxidize and mineralize new pollutants, thereby reducing their environmental risks. However, in practical water treatment scenarios, AEs face several unavoidable technical bottlenecks. Firstly, the concentration of new pollutants in natural water bodies is typically trace, while commonly present inorganic salts and natural organic matter compete strongly with the target pollutants, consuming large amounts of the ROS generated in the system. This significantly limits the actual removal rate of new pollutants, usually only reaching 20% ​​to 40%, failing to meet stringent water purification requirements. Secondly, AEs rely on adding oxidants to the water, commonly including persulfates. The addition of these oxidants directly leads to a significant increase in the salinity of the treated effluent, affecting not only the ecological compatibility of the water body but also potentially impacting subsequent water treatment processes or water reuse. More importantly, because the oxidation reaction of reactive oxygen species lacks sufficient selectivity, some new pollutants cannot be completely mineralized during the oxidation process, generating a series of more complex intermediate products. These intermediate products often remain in water bodies, and their environmental toxicity may be higher than that of the original pollutants, posing potential secondary risks to the ecological environment and human health.

[0004] In recent years, to address the limitations of advanced oxidation processes, various improved water treatment technologies have been developed, including oxidation technologies based on single-atom catalysts and electro-Fenton cathode catalysis technologies. Chinese invention patent application CN120515461 A describes a multilayer graphene-supported cobalt-nitrogen-carbon single-atom catalyst, overcoming the shortcomings of traditional symmetrical coordination catalysts in terms of activity, selectivity, and stability. However, this single-atom catalyst needs to be added to the wastewater along with the oxidant persulfate, leading to an increase in the salinity of the effluent.

[0005] Based on the above situation, it is necessary to develop a new water treatment method that can efficiently remove new pollutants from water bodies without being disturbed by inorganic salts and natural organic matter, without introducing oxidants into the water body, and without leaving intermediate product residues. Summary of the Invention

[0006] To address the technical problem of increased water salinity caused by direct contact between oxidants and water bodies, this invention provides a dual-chamber decoupled water treatment method and apparatus based on a graphite blanket-supported cobalt-manganese oxide composite material. This invention uses a graphite blanket as a carrier to in-situ deposit and support cobalt-manganese oxide as a composite activation material, and utilizes this material to construct a dual-chamber decoupled water treatment device based on a galvanic cell reactor design strategy. The device consists of a cathode chamber and an anode chamber, separated by a proton exchange membrane. The anode chamber contains the graphite blanket-supported cobalt-manganese oxide composite material, while the cathode chamber contains the graphite blanket-supported carbon nanotube composite material. The composite materials in the two chambers are connected by copper wires embedded in the top plate. Without direct contact between the oxidant and the water to be treated, new pollutants are efficiently removed from the water through an oxidative aggregation pathway, thus overcoming the shortcomings of existing water treatment technologies.

[0007] The technical solution of this invention is as follows: In a first aspect, the present invention provides a dual-chamber decoupled water treatment method based on a graphite blanket-supported cobalt-manganese oxide composite material, comprising the following steps: (1) Electrodes are assembled in the anode chamber and cathode chamber of the dual-chamber reactor, respectively. The anode electrode is a graphite blanket-supported cobalt-manganese oxide composite material. The preparation method of the graphite blanket-supported cobalt-manganese oxide composite material includes: a. Immerse the graphite blanket in a solution containing Co source and Mn source to obtain a mixed solution, wherein the molar ratio of Co to Mn in the mixed solution is 16:1 to 1:16; b. Add 30 mL of 0.1 mol / L to 0.4 mol / L KMnO4 solution dropwise to the mixture, then heat the mixture to 70℃ to 180℃, add 10 mL of 10% to 20% nitric acid and keep it warm and stirred for 1 h to 7 h, then add 5 mL of 0.1 mol / L to 0.3 mol / L NaOH solution, stir and cool to room temperature; c. Rinse the product and dry it to obtain the final product; The cathode electrode uses a graphite blanket-supported carbon nanotube composite material. Based on the area of ​​the graphite blanket, the carbon nanotube loading of the graphite blanket-supported carbon nanotube composite material is 2 g / m². 2 ~20 g / m 2 ; (2) Add the water sample to be treated to the anode chamber and add the oxidant solution to the cathode chamber. Connect the anode electrode and the cathode electrode with a wire to form a closed circuit and carry out advanced oxidation reaction.

[0008] Furthermore, the oxidant is selected from potassium persulfate complex salt (PMS, KHSO5·0.5KHSO4·0.5K2SO4), ammonium persulfate ((NH4)2S2O8), sodium hypochlorite (NaClO), hydrogen peroxide (H2O2), peracetic acid (PAA, CH3COOOH) or ozone (O3).

[0009] Furthermore, the concentration of the oxidant solution is 0.01 M ~ the saturation concentration of the oxidant.

[0010] Furthermore, the hydraulic residence time of the water sample to be treated in the dual-chamber reactor is 1 h to 20 h, preferably 3 h to 6 h.

[0011] Furthermore, the graphite blanket is calcined under a protective atmosphere before use to remove impurities and surface functional groups. The calcination temperature of the graphite blanket is selected from 300℃ to 1200℃, preferably 500℃ to 800℃.

[0012] Furthermore, the preparation method of graphite blanket-supported carbon nanotube composite material is as follows: Carbon nanotubes were dispersed in a mixture of deionized water, ethanol, and Nafion solution to obtain a suspension. The suspension was then dropped onto a graphite blanket. After the graphite blanket dried, it was washed several times with deionized water and finally dried.

[0013] Furthermore, in preparing the graphite blanket-supported carbon nanotube composite material, the carbon nanotubes are first acid-washed with nitric acid solution, then washed repeatedly with deionized water until neutral, and the washed carbon nanotubes are placed in an oven to dry.

[0014] Furthermore, in the mixed system of deionized water, ethanol, and Nafion solution, the volume ratio of deionized water to ethanol is 1:1, and the amount of Nafion solution added is 0.5 mL to 1 mL / 100 mL of ethanol aqueous solution.

[0015] In a second aspect, the present invention provides a dual-chamber decoupled water treatment device based on graphite blanket-loaded cobalt-manganese oxide composite material, comprising at least one dual-chamber reactor, wherein the anode chamber and cathode chamber of the dual-chamber reactor are separated by a proton exchange membrane. The anode chamber is used to hold the water sample to be treated, and the anode chamber is equipped with the above-mentioned graphite blanket-supported cobalt manganese oxide composite material as the anode electrode. The cathode chamber contains the oxidant solution and is equipped with a graphite blanket-supported carbon nanotube composite material as the cathode electrode. The carbon nanotube loading of the graphite blanket-supported carbon nanotube composite material is 2 g / m² based on the area of ​​the graphite blanket. 2 ~20 g / m 2 ; The anode and cathode electrodes are connected by a wire to form a closed circuit.

[0016] Furthermore, the dual-chamber reactor includes a top plate and an outer column with a bottom plate. The top of the top plate and the top of the outer column are matched. A proton exchange membrane with an annular structure is installed inside the dual-chamber reactor. The proton exchange membrane divides the internal space of the outer column into an inner cavity and an outer cavity. The inner cavity is the anode chamber and the outer cavity is the cathode chamber.

[0017] Furthermore, the lower surface of the top plate of the dual-chamber reactor and the upper surface of the bottom plate of the outer column are respectively provided with fixing grooves. The upper end of the fixing grid is embedded in the fixing groove on the lower surface of the top plate, and the lower end of the fixing grid is embedded in the fixing groove on the upper surface of the bottom plate. The proton exchange membrane is fixed to the fixing grid by screws.

[0018] Furthermore, a sealing gasket is installed between the fixed clamping groove and the fixed grid to ensure the sealing of the anode chamber and the cathode chamber. The sealing gasket is made of silicone rubber, fluororubber, EPDM rubber or nitrile rubber.

[0019] Furthermore, a sealing gasket is installed at the contact point between the top plate and the outer column. The sealing gasket is made of silicone rubber, fluororubber, EPDM rubber, or nitrile rubber.

[0020] Furthermore, the lower surface of the top plate is also equipped with an anode fixing clip and a cathode fixing clip. The fixing clip is made of corrosion-resistant and conductive material, such as titanium alloy, copper alloy with platinum plating, graphite material, etc. The anode fixing clip and the cathode fixing clip are connected by a wire, which can be copper wire, and the wire is embedded in the top plate.

[0021] Furthermore, the top plate is equipped with a chemical dosing port and a water outlet. The chemical dosing port is connected to the cathode chamber for injecting oxidant solution, and the water outlet is connected to the anode chamber for drawing out the treated water sample. The bottom plate is equipped with a water inlet, which is connected to the anode chamber for conveying the water sample to be treated.

[0022] Furthermore, both the anode and cathode chambers are equipped with stirring devices, which can be magnetic stirrers. When in use, the magnetic stirrers need to be used in conjunction with an external magnetic stirring base. The magnetic stirrers are driven to rotate by the external magnetic field of the magnetic stirring base to achieve stirring. Preferably, the magnetic stirrers can be made of polytetrafluoroethylene-coated neodymium iron boron magnets, which are acid and alkali resistant, oxidation resistant, and can resist the corrosion of media such as potassium persulfate compound salt and sodium hypochlorite in the oxidant chamber. At the same time, it can prevent the magnets from dissolving and polluting the water. The shape can be cylindrical or olive-shaped according to the size of the chamber to ensure that it can roll freely at the bottom of the chamber without colliding with the electrodes and proton exchange membrane.

[0023] Furthermore, the volume ratio of the anode chamber to the cathode chamber is 1 to 20:1; preferably, the sum of the volumes of the anode chamber and the cathode chamber is 0.2 L to 20 L.

[0024] Furthermore, the aforementioned dual-chamber decoupled water treatment device includes two or more dual-chamber reactors arranged in parallel with each other.

[0025] Furthermore, the outer column and top plate of the dual-chamber reactor are made of epoxy resin or engineering plastics, such as ABS, PVC, PP, etc.

[0026] The beneficial effects of this invention are as follows: This invention utilizes a graphite blanket-supported cobalt-manganese oxide composite material to construct a dual-chamber decoupled water treatment device. Without direct contact between the oxidant and the water being treated, it efficiently removes new pollutants from the water through an oxidative aggregation pathway. Compared to traditional advanced oxidation processes, this invention achieves simultaneous removal of new pollutants and total organic carbon, with a removal rate exceeding 94%, avoiding the residue of oxidation intermediates in the water. This invention eliminates the need to add oxidant to the water, preventing an increase in salinity. Furthermore, the removal efficiency is unaffected by inorganic ions and natural organic matter, solving the problems of interference from coexisting substances, increased effluent salinity, and secondary pollution inherent in traditional advanced oxidation processes. The graphite blanket-supported cobalt-manganese oxide composite material of this invention has low raw material costs, a simple preparation process, and stable performance. When its efficiency declines due to the accumulation of oxidative polymerization products, its activity can be restored after washing with methanol. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a physical image of the graphite blanket-supported cobalt manganese oxide composite material prepared in Example 1.

[0029] Figure 2This is the XRD pattern of the graphite blanket-supported cobalt manganese oxide composite material prepared in Example 1.

[0030] Figure 3 This is a SEM image of the graphite blanket-supported cobalt manganese oxide composite material prepared in Example 1.

[0031] Figure 4 This is a schematic diagram of the dual-chamber decoupled water treatment device in Example 4.

[0032] Figure 5 This is a graph showing the effect of bisphenol A treatment over time in Example 5.

[0033] Figure 6 This is a graph showing the change in total organic carbon treatment effect over time in Example 5.

[0034] Figure 7 This is a correlation graph between the bisphenol A removal rate and the total organic carbon removal rate in Example 5.

[0035] Figure 8 This is a mass spectrometry result of the effluent from Example 5.

[0036] Figure 9 This is a graph showing the change in effluent salinity over time in Example 5.

[0037] Figure 10 This is a bar chart showing the effect of inorganic ions and organic matter on the first-order reaction rate constant in Example 5.

[0038] Figure 11 This is the electrode continuous working efficiency recovery diagram of Example 5.

[0039] In the figure, 1-top plate, 2-outer column, 3-proton exchange membrane, 4-fixed grid, 5-anode electrode, 6-cathode electrode, 7-cathode chamber. Detailed Implementation

[0040] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0041] This invention first provides a graphite blanket-supported cobalt-manganese oxide composite material, which can be used as an anode electrode for the oxidative polymerization treatment of new pollutants. The preparation method of this composite material includes the following steps: a. Immerse the graphite blanket in a solution containing Co source and Mn source to obtain a mixed solution, wherein the molar ratio of Co to Mn in the mixed solution is 16:1 to 1:16; b. Add 30 mL of 0.1 mol / L to 0.4 mol / L KMnO4 solution dropwise to the mixture, then heat the mixture to 70℃ to 180℃, add 10 mL of 10% to 20% nitric acid and keep it warm and stirred for 1 h to 7 h, then add 5 mL of 0.1 mol / L to 0.3 mol / L NaOH solution, stir and cool to room temperature; c. Rinse the product and dry it to obtain the final product.

[0042] It should be further noted that the graphite blanket is calcined under a protective atmosphere before use to remove impurities and surface functional groups. The calcination temperature of the graphite blanket is selected from 300℃ to 1200℃, preferably 500℃ to 800℃. The protective atmosphere (argon or nitrogen) can prevent the graphite blanket from oxidizing. The core function of calcination is to remove adsorbed organic impurities and unstable functional groups on the surface through high temperature, while optimizing the conductivity of the graphite blanket. The preferred temperature of 500℃ to 800℃ can thoroughly remove impurities while avoiding excessive temperature that could cause the graphite blanket structure to become brittle, ensuring its mechanical strength and electron transfer performance as an electrode carrier.

[0043] This invention provides a dual-chamber decoupled water treatment device based on the above-mentioned graphite blanket-supported cobalt manganese oxide composite material, comprising at least one dual-chamber reactor, wherein the anode chamber and cathode chamber of the dual-chamber reactor are separated by a proton exchange membrane. The anode chamber is used to hold the water sample to be treated, and the anode chamber is equipped with the above-mentioned graphite blanket-supported cobalt manganese oxide composite material as the anode electrode. The cathode chamber contains the oxidant solution and is equipped with a graphite blanket-supported carbon nanotube composite material as the cathode electrode. The carbon nanotube loading of the graphite blanket-supported carbon nanotube composite material is 2 g / m² based on the area of ​​the graphite blanket. 2 ~20 g / m 2 ; The graphite blanket-loaded cobalt manganese oxide composite material and the graphite blanket-loaded carbon nanotube composite material are connected by wires to form a closed loop.

[0044] The above structural design achieves physical isolation between the oxidant and the water to be treated through spatial separation, avoiding the problem of increased salinity caused by direct contact between the oxidant and the water. At the same time, the proton exchange membrane allows protons to migrate across the membrane, ensuring charge balance to maintain the continuous reaction.

[0045] It should be further noted that the graphite blanket-supported carbon nanotube composite material used in the above-mentioned dual-chamber decoupled water treatment device can be obtained by the following preparation method: Carbon nanotubes were dispersed in a mixture of deionized water, ethanol, and Nafion solution to obtain a suspension. The suspension was then dropped onto a graphite blanket. After the graphite blanket dried, it was washed several times with deionized water and finally dried.

[0046] It should be further noted that in the mixed system of deionized water, ethanol, and Nafion solution, the volume ratio of deionized water to ethanol is 1:1.

[0047] It should be further explained that carbon nanotubes are mixed with ethanol, deionized water and Nafion solution, and then treated sequentially by an ultrasonic mixer and a magnetic stirrer to obtain a suspension; preferably, the ultrasonic mixer has a power of 100 W to 300 W, the ultrasonic time is 30 min to 60 min, and the magnetic stirrer speed is 100 rpm to 800 rpm.

[0048] It should be further explained that the dual-chamber reactor includes a top plate and an outer column with a bottom plate. The top of the top plate and the top of the outer column are matched. A proton exchange membrane with an annular structure is installed inside the dual-chamber reactor. The proton exchange membrane divides the internal space of the outer column into an inner cavity and an outer cavity. The inner cavity is the anode chamber and the outer cavity is the cathode chamber.

[0049] It should be further explained that the lower surface of the top plate of the dual-chamber reactor and the upper surface of the bottom plate of the outer column are respectively provided with fixing grooves. The upper end of the fixing grid is embedded in the fixing groove on the lower surface of the top plate, and the lower end of the fixing grid is embedded in the fixing groove on the upper surface of the bottom plate. The proton exchange membrane is fixed to the fixing grid with screws. The screw fixing method can effectively prevent the proton exchange membrane from shifting during hydraulic fluctuations or stirring, and ensure the stability of the isolation effect between the two chambers.

[0050] It should be further noted that a sealing gasket is installed at the contact point between the top plate and the outer column. The sealing gasket is made of silicone rubber, fluororubber, EPDM rubber, or nitrile rubber.

[0051] It should be further explained that the lower surface of the top plate of the dual-chamber reactor and the upper surface of the bottom plate of the outer column are respectively provided with fixing grooves. The upper end of the fixing grid is embedded in the fixing groove on the lower surface of the top plate, and the lower end of the fixing grid is embedded in the fixing groove on the upper surface of the bottom plate. The proton exchange membrane is fixed to the fixing grid by screws.

[0052] It should be further explained that a sealing gasket is installed between the fixed clamping groove and the fixed grid to ensure the airtightness of the anode chamber and the cathode chamber. The sealing gasket is made of silicone rubber, fluororubber, EPDM rubber or nitrile rubber.

[0053] It should be further explained that an anode fixing clip and a cathode fixing clip are also provided on the lower surface of the top plate. The fixing clip is made of corrosion-resistant and conductive material, such as titanium alloy, copper alloy with platinum plating, graphite material, etc. The anode fixing clip and the cathode fixing clip are connected by a wire, which can be copper wire, and the wire is embedded in the top plate.

[0054] It should be further explained that the top plate is equipped with a chemical dosing port and a water outlet. The chemical dosing port is connected to the cathode chamber for injecting oxidant solution, and the water outlet is connected to the anode chamber for drawing out the treated water sample.

[0055] It should be further explained that the bottom plate is equipped with a water inlet, which is connected to the anode chamber for conveying the water sample to be treated.

[0056] It should be further noted that the outer column and top plate of the dual-chamber reactor are made of epoxy resin or engineering plastics, such as ABS, PVC, and PP. These materials have good corrosion resistance, mechanical strength, and processing performance, and can resist long-term erosion by media such as water and oxidants. At the same time, they are relatively inexpensive, easy to mass-produce, and meet the economic and practical requirements of water treatment equipment.

[0057] The aforementioned dual-chamber decoupled water treatment device uses a proton exchange membrane to separate the oxidant and the water to be treated. The direct electron transfer between the new pollutants and the oxidant is driven by the potential difference (ΔE) between the graphite blanket-supported cobalt-manganese oxide composite material in the anode chamber and the graphite blanket-supported carbon nanotube composite material in the cathode chamber. Specifically, the new pollutants lose electrons on the surface of the graphite blanket-supported cobalt-manganese oxide composite material, where they are oxidized and dehydrogenated to generate organic free radicals. These free radicals then aggregate into macromolecules through reactions such as para / ortho-CO coupling and para-CC coupling. These polymers are adsorbed onto the surface of the composite material, achieving efficient separation and simultaneously achieving deep removal of both pollutants and total organic carbon. Meanwhile, the oxidant gains electrons on the surface of the graphite blanket-supported carbon nanotube composite material, ensuring the efficiency of the oxidation of the new pollutants.

[0058] Meanwhile, the present invention also provides a dual-chamber decoupled water treatment method based on the above-mentioned graphite blanket-supported cobalt-manganese oxide composite material, which is applicable to wastewater containing new pollutants such as bisphenol A and phenol. This water treatment method can be implemented by the above-mentioned dual-chamber decoupled water treatment device and includes the following steps: (1) Electrodes are assembled in the anode chamber and cathode chamber of the dual-chamber reactor, respectively, wherein the anode electrode is a graphite blanket-supported cobalt manganese oxide composite material; The cathode electrode uses a graphite blanket-supported carbon nanotube composite material; (2) Add the water sample to be treated to the anode chamber and add the oxidant solution to the cathode chamber. Connect the anode electrode and the cathode electrode with a wire to form a closed circuit and carry out advanced oxidation reaction. When the reaction starts, the potential difference (ΔE) between the anode chamber and the cathode chamber is ≥0.5 V.

[0059] It should be further explained that the oxidant is selected from potassium persulfate complex salt (PMS, KHSO5·0.5KHSO4·0.5K2SO4), ammonium persulfate ((NH4)2S2O8), sodium hypochlorite (NaClO), hydrogen peroxide (H2O2), peracetic acid (PAA, CH3COOOH), or ozone (O3). These oxidants can be efficiently activated on the cathode electrode surface to generate strong oxidizing species such as hydroxyl radicals and sulfate radicals. They indirectly oxidize and degrade pollutants in the water through electron transfer, avoiding the increase in salinity caused by direct dissolution. Among them, potassium persulfate complex salt is preferred due to its high stability and excellent activation efficiency.

[0060] It should be further noted that the concentration of the oxidant solution is 0.01 M ~ the saturation concentration of the oxidant.

[0061] It should be further noted that the potential difference ΔE between the two chambers was monitored by an electrochemical workstation to ensure that ΔE ≥ 0.5 V at the start of the reaction; the initial pH of the water sample in the anode chamber was adjusted to 7.0 using HCl or NaOH.

[0062] It should be further noted that the hydraulic residence time of the water sample to be treated in the dual-chamber reactor is 1 h to 20 h, preferably 3 h to 6 h.

[0063] It should be further noted that when the effluent water quality is detected to be lower than the set standard, at least one of the following operations should be performed: A. Composite material regeneration: Take out the graphite blanket-loaded cobalt manganese oxide composite material and the graphite blanket-loaded carbon nanotube composite material, and use physical flushing, chemical soaking and other cleaning procedures to remove the intermediate products accumulated on the electrode surface. After performance verification, they are reassembled for use. B. Oxidant replacement: The failed oxidant is discharged through a negative pressure extraction device, and fresh oxidant is replenished to above the set threshold to complete the system reset.

[0064] Example 1 I. Preparation of graphite blanket-supported cobalt-manganese oxide composite materials Take 10 g of graphite blanket and calcine it in a tube furnace at 800℃ for 2 h under an argon atmosphere. Weigh 1.58 g of KMnO4 and add it to 30 mL of deionized water, stirring magnetically for 10 min until completely dissolved to obtain a KMnO4 solution with a concentration of 0.33 mol / L. Weigh 2.53 g of MnSO4 and add it to 40 mL of deionized water, stirring magnetically for 10 min until completely dissolved to obtain a MnSO4 solution. Weigh out the corresponding proportion of Co(NO3)2. 6H₂O (Co:Mn = 1:2) was added to the MnSO₄ solution and magnetically stirred until completely dissolved. The pretreated graphite blanket was completely immersed in the above mixed solution, and KMnO₄ solution was slowly added dropwise while stirring continuously for 10 min. The mixture was then heated to 90°C in an oil bath, and 10 mL of 10% nitric acid solution was slowly added while timing was maintained. Heating and stirring were continued for 4 h, followed by the addition of 5 mL of 0.25 mol / L NaOH solution. After stirring for 10 min, the mixture was cooled to room temperature. The product was repeatedly washed with deionized water until the filtrate was neutral, and then dried at 60°C for 24 h to obtain the graphite blanket-supported cobalt-manganese oxide composite material.

[0065] Figure 1 This is a physical image of the graphite blanket-supported cobalt-manganese oxide composite material prepared in this embodiment. Figure 2 The image shows the XRD pattern of the graphite blanket-supported cobalt-manganese oxide composite material prepared in this embodiment. The characteristic peaks of MnO2 (PDF#44-0141) and Co3O4 (PDF#42-1467) can be seen by XRD detection. Figure 3 The image shows a SEM image of the graphite blanket-supported cobalt-manganese oxide composite material prepared in this embodiment. The observation shows that the graphite blanket-supported cobalt-manganese oxide composite material consists of rod-shaped nanoparticles with a diameter of 30 nm to 50 nm, and Co and Mn elements are uniformly dispersed.

[0066] II. Preparation of Graphite Blanket-Supported Carbon Nanotube Composites Take 10 g of graphite blanket and calcine it in a tube furnace at 800℃ for 2 h under an argon atmosphere to remove surface impurities and functional groups. Cool it to room temperature for later use. Weigh 5 g of carbon nanotubes and disperse them in 100 mL of 30 wt% nitric acid solution to form a 5 wt% carbon nanotube dispersion. Place the dispersion in a 100℃ oil bath for acid washing for 2 h, and maintain magnetic stirring at 300 rpm to ensure that the carbon nanotubes are in full contact with the nitric acid. After acid washing, rinse the carbon nanotubes repeatedly with deionized water until the washing solution is neutral. Place the washed carbon nanotubes in an 80℃ oven for 12 h to dry, and obtain pretreated carbon nanotubes.

[0067] Mix 50 mL of deionized water and 50 mL of ethanol at a volume ratio of 1:1, add 0.5 mL of Nafion solution, and then add the dried pretreated carbon nanotubes to form a mixture. Place the mixture in a 200 W ultrasonic mixer and sonicate for 60 min. Then transfer it to a magnetic stirrer and stir continuously at 600 rpm for 4 h to obtain a stable and uniform carbon nanotube suspension.

[0068] The pretreated graphite blanket was laid flat on a clean glass slide. A carbon nanotube suspension was then uniformly added to the graphite blanket surface using a peristaltic pump at a rate of 1 mL / min, controlling the carbon nanotube loading per unit area of ​​the graphite blanket to be 10 g / m². 2 After the addition was completed, the graphite blanket was placed in a 60℃ oven and dried for 16 h. Then it was washed three times with deionized water to remove the unbonded carbon nanotubes and excess Nafion. Finally, it was placed in an 80℃ oven and dried for 8 h to obtain the graphite blanket-supported carbon nanotube composite material.

[0069] Example 2 Take 10 g of graphite blanket and calcine it in a tube furnace at 1200℃ for 1 h under an argon atmosphere. Weigh 0.47 g of KMnO4 and add it to 30 mL of deionized water, stirring magnetically for 10 min until completely dissolved to obtain a 0.1 mol / L KMnO4 solution. Weigh 0.223 g of MnSO4 and add it to 40 mL of deionized water, stirring magnetically for 10 min until completely dissolved to obtain a MnSO4 solution. Weigh the corresponding proportion of Co(NO3)2. 6H₂O (Co:Mn = 16:1) was added to the MnSO₄ solution and magnetically stirred until completely dissolved. The pretreated graphite blanket was completely immersed in the above mixed solution, and KMnO₄ solution was slowly added dropwise while stirring continuously for 10 min. The mixture was placed in an oil bath and heated to 70 °C. 10 mL of 20% nitric acid solution was slowly added and the time was kept on, and the mixture was heated and stirred continuously for 7 h. Then, 5 mL of 0.3 mol / L NaOH solution was added, and the mixture was stirred for 10 min before cooling to room temperature. The product was repeatedly washed with deionized water until the filtrate was neutral, and dried at 60 °C for 24 h to obtain the graphite blanket-supported cobalt-manganese oxide composite material.

[0070] Example 3 Take 10 g of graphite blanket and calcine it in a tube furnace at 500℃ for 6 h under an argon atmosphere. Weigh 1.90 g of KMnO4 and add it to 30 mL of deionized water, stirring magnetically for 10 min until completely dissolved to obtain a 0.4 mol / L KMnO4 solution. Weigh 3.57 g of MnSO4 and add it to 40 mL of deionized water, stirring magnetically for 10 min until completely dissolved to obtain a MnSO4 solution. Weigh out the corresponding proportion of Co(NO3)2. 6H₂O (Co:Mn = 16:1) was added to the MnSO₄ solution and magnetically stirred until completely dissolved. The pretreated graphite blanket was completely immersed in the above mixed solution, and KMnO₄ solution was slowly added dropwise while stirring continuously for 10 min. The mixture was then heated to 180℃ in an oil bath, and 10 mL of 15% nitric acid solution was slowly added while timing was maintained. Heating and stirring were continued for 1 h, followed by the addition of 5 mL of 0.1 mol / L NaOH solution. After stirring for 10 min, the mixture was cooled to room temperature. The product was repeatedly washed with deionized water until the filtrate was neutral, and then dried at 60℃ for 24 h to obtain the graphite blanket-supported cobalt-manganese oxide composite material.

[0071] Example 4 Construction of a dual-chamber decoupled oxidation device like Figure 4 As shown, a dual-chamber reactor is used. The dual-chamber reactor includes a top plate 1 and an outer column 2 with a bottom plate. The tops of the top plate 1 and the outer column 2 are fitted together, and a sealing gasket is installed at the contact point between the top plate 1 and the outer column 2. A ring-shaped proton exchange membrane 3 is installed inside the dual-chamber reactor. The proton exchange membrane 3 divides the internal space of the outer column into an inner cavity and an outer cavity. The inner cavity is the anode chamber with a volume of 10 L, and the outer cavity is the cathode chamber with a volume of 0.5 L.

[0072] In this dual-chamber reactor, the lower surface of the top plate 1 and the upper surface of the bottom plate of the outer column 2 are respectively provided with fixing grooves. The upper end of the fixing grid 4 is embedded in the fixing groove on the lower surface of the top plate 1, and the lower end of the fixing grid 4 is embedded in the fixing groove on the upper surface of the bottom plate. The proton exchange membrane 3 is fixed to the fixing grid 4 with screws. A sealing gasket is provided between the fixing groove and the fixing grid 4.

[0073] The lower surface of the top plate 1 is provided with an anode fixing clip and a cathode fixing clip. The fixing clip is made of corrosion-resistant conductive material. The anode fixing clip and the cathode fixing clip are connected by a wire, which can be copper wire, and the wire is embedded in the top plate. The top plate 1 is provided with a chemical dosing port and a water outlet. The chemical dosing port is connected to the cathode chamber for injecting oxidant solution, and the water outlet is connected to the anode chamber for drawing out the treated water sample. The bottom plate is provided with a water inlet, which is connected to the anode chamber for transporting the water sample to be treated.

[0074] In the anode chamber, the graphite blanket-loaded cobalt-manganese oxide composite material prepared in Example 1 is assembled as the anode electrode 5 using an anode fixing clamp. In the cathode chamber 7, the graphite blanket-loaded carbon nanotube composite material prepared in Example 1 is assembled as the cathode electrode 6 using a cathode fixing clamp. The anode electrode 5 and the cathode electrode 6 can be connected to form a closed circuit through copper wires embedded in the top plate 1.

[0075] The anode chamber and cathode chamber 7 are each equipped with magnetic stirrers, and the dual-chamber reactor is placed on a magnetic stirrer.

[0076] Example 5 Bisphenol A Removal Experiment First, using the dual-chamber decoupled water treatment device of Example 4, 0.5 L of 0.1 mol / L PMS solution was injected into the cathode chamber through the dosing port, ensuring that the graphite blanket-supported carbon nanotube composite material in the cathode chamber was completely immersed in the PMS solution. Then, a peristaltic pump was started to deliver 10 L of 50 mg / L bisphenol A simulated water sample from the inlet to the anode chamber at a flow rate of 5 mL / min. Simultaneously, the magnetic stirrer was activated, and the stirring speed in the anode chamber was adjusted to 750 rpm and in the cathode chamber to 500 rpm, ensuring sufficient contact between the water sample and the anode electrode and uniform distribution of the oxidant solution. After the anode chamber was filled with water sample, the copper wire circuit embedded in the top plate was closed, and the potential difference between the two chambers was monitored using an electrochemical workstation (CHI760E) to ensure that the potential difference ΔE ≥ 0.5 V. If ΔE was lower than 0.5 V, PMS solution was added through the dosing port until ΔE met the requirement.

[0077] During the reaction, 1 mL samples were taken from the outlet of the anode chamber at 0 min, 15 min, 30 min, 45 min, 60 min, 90 min, and 120 min, respectively. Residual water in the conduit was drained before sampling to ensure the sample was a real-time water sample from the anode chamber. After filtration through a 0.22 μm PTFE membrane, the concentration of bisphenol A was determined by high-performance liquid chromatography (HPLC, Shimadzu LC-20A). The chromatographic conditions were: a C18 column (250 × 4.6 mm), a mobile phase of methanol:water = 70:30 (v / v), a flow rate of 1.0 mL / min, and a detection wavelength of 278 nm.

[0078] The results are as follows Figure 5 , Figure 6 As shown, after 90 minutes of reaction, the ratio of the residual concentration C of bisphenol A in the effluent to the initial concentration C0 of bisphenol A is 0, meaning the bisphenol A removal rate reaches 100%, and the corresponding total organic carbon removal rate is 94.19%. Figure 7As shown, the removal rate of bisphenol A (BPA) and the removal rate of total organic carbon (TOC) exhibit a significant and strong positive correlation. With the increase in BPA removal rate, the TOC removal rate also increases synchronously, indicating that in the dual-chamber decoupled water treatment process, BPA undergoes oxidative polymerization and is separated from the water, achieving effective removal of organic carbon from the water. After the reaction, functional groups such as C=O and COC were detected on the surface of the anode electrode by FTIR, and high-resolution mass spectrometry (e.g., [missing data]) was also observed on the anode electrode. Figure 8 As shown, the signal peaks of the surface adsorbate were mainly concentrated in the medium-mass range of 300-800 with a mass-to-charge ratio (m / z). This range corresponds to a molecular structure with a large mass, indicating that bisphenol A undergoes oxidative polymerization, and the resulting multiple large-mass oxidative polymers are eventually adsorbed on the surface of the anode electrode.

[0079] Figure 9 The curves showing the salinity changes of the effluent at the initial time, 30 min, 60 min, 90 min, and 120 min during the bisphenol A treatment process can be seen. It can be seen that the salinity of the effluent has always been maintained at a stable level of about 0.5 g / L without significant fluctuations, indicating that the method of the present invention can effectively avoid the problems of increased effluent salinity and secondary pollution that exist in traditional advanced oxidation processes.

[0080] To verify whether inorganic ions and organic matter affect the implementation of the method of this invention, the above experiment was used as a control group. Bisphenol A simulated water sample was then added with bicarbonate ions (HCO3-). - ), sulfate ions (SO4) 2- ), chloride ions (Cl) - ), nitrate ions (NO3) - The above experimental method was repeated to determine the first-order reaction rate constant K of each system, including humic acid (HA) and organic matter. ops The result is as follows Figure 10 As shown, the removal efficiency of the method of the present invention is not affected by inorganic ions and organic matter, thus solving the problem that traditional advanced oxidation processes are easily affected by coexisting substances.

[0081] After the above experiment, the electrode surface was rinsed with deionized water, and then the 50 mg / L bisphenol A solution was cyclically treated under the same conditions. The results are as follows: Figure 11 As shown, the removal rate of bisphenol A remained at 100% in the first 20 cycles, and still reached 92% in the 22nd cycle. After the 24th cycle, the removal rate dropped to 15%. After washing with methanol, the catalyst activity was restored, and the removal rate rebounded to 98% in the 25th cycle. This proves that the slowdown in removal efficiency caused by the accumulation of oxidative polymerization products can be improved by methanol washing without causing deactivation of the electrode material.

[0082] Comparative Example 1 Comparative Example 1 used a pure graphite blanket as the anode electrode, and kept the other conditions the same as in Example 5 to conduct a bisphenol A removal experiment.

[0083] After 180 minutes of treatment, the removal rate of bisphenol A was only 12%.

[0084] Comparative Example 2 Comparative Example 2 used a graphite blanket-loaded cobalt oxide material as the anode electrode, and the other conditions were kept the same as in Example 5 for bisphenol A removal experiments.

[0085] The preparation method of the graphite blanket-supported cobalt oxide material is the same as in Example 1, except that Co(NO3)2 is used instead of MnSO4.

[0086] After 180 minutes of treatment, the bisphenol A removal rate was only 45%.

[0087] Comparative Example 3 Comparative Example 3 used a graphite blanket-loaded manganese oxide composite material as the anode electrode, and the other conditions were kept the same as in Example 5 for bisphenol A removal experiments.

[0088] The preparation method of the graphite blanket-supported cobalt oxide material is the same as in Example 1, except that MnSO4 is used instead of Co(NO3)2.

[0089] After 180 minutes of treatment, the removal rate of bisphenol A was only 62%.

[0090] Example 6: Phenol Removal Experiment 10 L of a phenol-simulated water sample with a concentration of 50 mg / L and 0.5 L of a PMS solution with a concentration of 0.1 mol / L were prepared and introduced into the anode and cathode chambers of the dual-chamber reactor in Example 4, respectively. The reaction was started by connecting the lead wires. At 0, 15, 30, 45, 60, 90, 120, 150, 180, and 240 min, 1 mL of sample was taken from the anode chamber, filtered through a 0.22 μm PTFE membrane, and the phenol concentration was detected by high-performance liquid chromatography (HPLC, Shimadzu LC-20A). The chromatographic conditions were as follows: C18 column (250 × 4.6 mm), mobile phase: methanol:water = 65:35 (v / v), flow rate: 1.0 mL / min, and detection wavelength: 270 nm.

[0091] After 80 min of reaction, the phenol removal rate reached 100% and the total organic carbon removal rate reached 92.35%. After the reaction, functional groups such as C=O and COC were detected on the catalyst surface by FTIR.

[0092] Example 7: Actual Wastewater Treatment Experiment Wastewater from a wastewater treatment plant in Jimo District, Qingdao City, Shandong Province, was treated with 50 mg / L bisphenol A as the sample. The apparatus and method described in Example 5 were used for treatment, with the conventional Fenton process and ozone oxidation process serving as controls. The results showed that using the apparatus and method of Example 5, bisphenol A was completely removed within a hydraulic retention time of 4 hours, with a total organic carbon removal rate exceeding 90%; using the conventional Fenton process, the total organic carbon removal rate was only 25.12% with a hydraulic retention time of 4 hours; and using the ozone oxidation process, the total organic carbon removal rate was only 51% with a hydraulic retention time of 4 hours. This indicates that the apparatus and method of the present invention have superior treatment efficiency for actual wastewater and are unaffected by interference from coexisting substances.

[0093] Although the present invention has been described in detail with reference to the accompanying drawings and preferred embodiments, the present invention is not limited thereto. Various equivalent modifications or substitutions can be made to the embodiments of the present invention by those skilled in the art without departing from the spirit and essence of the invention, and such modifications or substitutions should all be within the scope of the present invention. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should also be covered within the protection scope of the present invention.

Claims

1. A dual-chamber decoupled water treatment method based on graphite blanket-supported cobalt-manganese oxide composite material, characterized in that, The steps are as follows: (1) Electrodes are assembled in the anode and cathode chambers of the dual-chamber reactor, respectively. The anode and cathode chambers of the dual-chamber reactor are separated by a proton exchange membrane. The anode electrode is made of graphite blanket-supported cobalt-manganese oxide composite material. The preparation method of graphite blanket-supported cobalt-manganese oxide composite material includes: a. Take 10 g of graphite blanket and place it in a tube furnace. Calcinate it at 800℃ for 2 h under an argon atmosphere. Weigh 2.53 g of MnSO4 and add 40 mL of deionized water. Stir magnetically for 10 min until completely dissolved to obtain MnSO4 solution. Weigh out the corresponding proportion of Co(NO3)2·6H2O and add it to the MnSO4 solution. Control the Co:Mn = 1:

2. Stir magnetically until completely dissolved. Immerse the graphite blanket in the solution containing the Co source and Mn source to obtain a mixed solution. b. Add 30 mL of 0.33 mol / L KMnO4 solution to the mixture, then heat the mixture to 90℃, add 10 mL of 10% nitric acid and keep it warm and stirred for 4 h, then add 5 mL of 0.25 mol / L NaOH solution, stir and cool to room temperature; c. Rinse the product and dry it to obtain the final product; The cathode electrode uses a graphite blanket-supported carbon nanotube composite material. Based on the area of ​​the graphite blanket, the carbon nanotube loading of the graphite blanket-supported carbon nanotube composite material is 10 g / m². 2 ; (2) Add the water sample to be treated to the anode chamber and add 0.1 mol / L PMS solution to the cathode chamber. Connect the anode electrode and the cathode electrode with a wire to form a closed circuit and carry out the advanced oxidation reaction. The potential difference between the anode chamber and the cathode chamber is ≥0.5 V when the reaction starts. The new pollutants lose electrons on the surface of the cobalt-manganese oxide composite material supported by the graphite blanket. At this time, the new pollutants are oxidized and dehydrogenated to generate organic free radicals, which then aggregate into macromolecules. These polymer products are adsorbed on the surface of the composite material. The water sample to be treated was 10 L of bisphenol A with a concentration of 50 mg / L. After 90 min of reaction, the bisphenol A removal rate reached 100%, and the total organic carbon removal rate reached 94.19%. The water sample to be treated contained 10 L of phenol with a concentration of 50 mg / L. After 80 min of reaction, the phenol removal rate reached 100% and the total organic carbon removal rate reached 92.35%.

2. The dual-chamber decoupled water treatment method as described in claim 1, characterized in that, The hydraulic residence time of the water sample to be treated in the two-chamber reactor is 1 h to 20 h.

3. The dual-chamber decoupled water treatment method as described in claim 1, characterized in that, The preparation method of graphite blanket-supported carbon nanotube composite material is as follows: Carbon nanotubes were dispersed in a mixture of deionized water, ethanol, and Nafion solution to obtain a suspension. The suspension was then dropped onto a graphite blanket. After the graphite blanket dried, it was washed several times with deionized water and finally dried.

4. The dual-chamber decoupled water treatment method as described in claim 3, characterized in that, In the mixed system of deionized water, ethanol and Nafion solution, the volume ratio of deionized water to ethanol is 1:1, and the amount of Nafion solution added is 0.5 mL to 1 mL / 100 mL of ethanol aqueous solution.

5. The dual-chamber decoupled water treatment method as described in claim 1, characterized in that, The dual-chamber reactor includes a top plate and an outer column with a bottom plate. The top of the top plate and the top of the outer column are matched. A proton exchange membrane with an annular structure is installed inside the dual-chamber reactor. The proton exchange membrane divides the internal space of the outer column into an inner cavity and an outer cavity. The inner cavity is the anode chamber and the outer cavity is the cathode chamber.

6. The dual-chamber decoupled water treatment method as described in claim 5, characterized in that, The lower surface of the top plate of the dual-chamber reactor and the upper surface of the bottom plate of the outer column are respectively provided with fixing grooves. The upper end of the fixing grid is embedded in the fixing groove on the lower surface of the top plate, and the lower end of the fixing grid is embedded in the fixing groove on the upper surface of the bottom plate. The proton exchange membrane is fixed to the fixing grid by screws.

7. The dual-chamber decoupled water treatment method as described in claim 6, characterized in that, The lower surface of the top plate is also equipped with an anode fixing clip and a cathode fixing clip, which are connected by a wire embedded in the top plate.

Images