A method and apparatus for synergistic treatment of novel pollutants by multi-source catalytic coupling adsorption

Abstract

This invention discloses a method and apparatus for the synergistic treatment of novel pollutants through multi-source catalytic coupling adsorption. The method includes dispersing graphene oxide in an aqueous solution and adding iron, copper, and cerium salts to dissolve them, obtaining a mixed solution. Pretreated granular activated carbon is impregnated in the mixed solution, stirred, filtered, dried, and then calcined. After cooling and washing, a modified activated carbon adsorption packing is obtained. The modified activated carbon adsorption packing is placed in a reactor containing an anode and a cathode. An electrolyte is added to the reactor, and wastewater containing novel pollutants is introduced into the reactor. Electricity is applied and the current density is controlled to a preset value to complete the pollutant treatment. The novel pollutants include perfluorooctanoic acid (PFOA), tributyl phosphate (TFP), and tris(2-chloroethyl) phosphate. This method achieves synergistic treatment of multiple novel pollutants, is simple to operate, has low operating costs, and shows good application prospects.

Description

Technical Field

[0001] This invention belongs to the field of water pollution treatment technology, specifically relating to a method and apparatus for the synergistic treatment of new pollutants through multi-source catalytic coupling adsorption. Background Technology

[0002] Currently, the main emerging pollutants of concern fall into four categories: endocrine disruptors, perfluorinated compounds, microplastics, and antibiotics. While the overall concentration of these pollutants in the environment is low, they exhibit characteristics such as stability, difficulty in decomposition, and easy accumulation. Long-term low-dose exposure may pose significant risks to human health and the ecological environment.

[0003] Currently, numerous literature reports on technologies for removing new pollutants, such as biological methods, adsorption methods, chemical oxidation methods, membrane technologies, and advanced oxidation methods. According to incomplete statistics, adsorption, photocatalytic oxidation, biological methods, and ozone oxidation are the four most researched removal technologies, accounting for approximately 66% of all related research. Activated carbon is the most commonly used adsorbent in wastewater treatment, used to remove various conventional pollutants as well as recalcitrant organic pollutants. The activated carbon adsorption process is influenced by many factors, including the properties of the activated carbon itself, such as the materials used, specific surface area, and surface chemical properties; the physicochemical properties of the new pollutants, such as hydrophobicity, solubility, charge, and molecular size; the chemical properties and composition of the solution, such as soluble organic matter; and other basic parameters such as the activated carbon dosage and adsorbate concentration. Based on practical experience, the main problems with activated carbon adsorption in actual operation are the competition for adsorption sites from other coexisting organic matter in the wastewater and the reduction in adsorption efficiency due to pore blockage. Additionally, the adsorption process generates a large amount of carbon-containing sludge, which correspondingly increases the energy consumption for sludge treatment.

[0004] Chinese patent CN117383665A discloses a three-dimensional electro-Fenton particle electrode with iron / copper needle coke and its preparation method. This method involves loading copper onto needle coke using an impregnation-calcination method, then uniformly mixing iron oxides, copper-modified needle coke, a binder, and anhydrous ethanol. The mixture is then pressed into shape and calcined at high temperature under nitrogen to obtain the three-dimensional electro-Fenton particle electrode with iron / copper needle coke. This method promotes the Fenton chain reaction through binary metal-modified particle electrodes, achieving highly efficient degradation of organic matter. The removal efficiency of conventional pollutants such as COD and ammonia nitrogen in landfill leachate can reach over 90%. However, the required particle electrode dosage in the reaction system is 25 g / L, resulting in high pollutant removal costs. The optimal reaction time is 6 hours, indicating low system reaction efficiency. Furthermore, this method only shows good removal effects on conventional pollutants in landfill leachate and has not been validated for the removal of new pollutants in wastewater. Therefore, it cannot meet the needs of synergistic removal of multiple pollutants in actual wastewater, and its practical application advantages are not significant. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method and apparatus for the synergistic treatment of new pollutants through multi-source catalytic coupling adsorption. It combines the high-efficiency adsorption of modified activated carbon with electrochemical oxidation, which greatly enhances the degradation efficiency of traditional three-dimensional (3D) electrochemical reaction systems for new pollutants and overcomes the disadvantages of high treatment costs, low reaction efficiency, and poor synergistic removal effect of new pollutants.

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

[0007] This invention provides a method for the synergistic treatment of novel pollutants through multi-source catalytic coupling adsorption, comprising the following steps:

[0008] Graphene oxide is dispersed in an aqueous solution, and then iron salt, copper salt, and cerium salt are added to dissolve them, resulting in a mixed solution.

[0009] Pretreated granular activated carbon is impregnated in a mixed solution, stirred, filtered, dried, and then calcined. Finally, it is cooled and washed to obtain modified activated carbon adsorption filler.

[0010] The modified activated carbon adsorption packing is placed in a reactor containing an anode and a cathode;

[0011] Electrolytes are added to the reactor, wastewater containing new pollutants is introduced into the reactor, electricity is applied and the current density is controlled to a preset value to complete the pollutant treatment; wherein, the new pollutants include perfluorooctanoic acid, tributyl phosphate and tris(2-chloroethyl) phosphate.

[0012] Furthermore, the iron salt, copper salt, and cerium salt are FeCl3, CuCl2·2H2O, and CeCl3, respectively, and the molar ratio of FeCl3, CuCl2·2H2O, and CeCl3 is (0.005~0.03): (0.01~0.02): (0.01~0.02).

[0013] Furthermore, the ratio of the mass of the graphene oxide to the total mass of the iron salt, copper salt, and cerium salt is 0.2:(0.8~3), and the number of layers of the graphene oxide is less than 10.

[0014] Furthermore, the pretreatment method includes: selecting 8-30 mesh granular activated carbon, first washing it with deionized water, then washing it with anhydrous ethanol, then placing it in an ultrasonic cleaner for 20-40 minutes, then immersing it in a water bath at 75-85°C for 5-15 minutes, and finally drying it in an oven at 55-65°C for 10-14 hours for later use.

[0015] Furthermore, the calcination treatment conditions are as follows: under a nitrogen atmosphere, in a vacuum box furnace, the temperature is increased to 700-900℃ at a rate of 5-10℃ / min and calcined for 2-4 hours.

[0016] Furthermore, both the cathode and the anode are annular mesh metal electrodes. The anode and the cathode are respectively positioned close to the inner wall and the middle of the reactor and are arranged in parallel at the same height, with a spacing of 0.8~8cm between them.

[0017] Furthermore, when introducing wastewater containing new pollutants into the reactor, the initial pH is adjusted to 4.5-5.5; the preset value for the current density is 1-5 mA / cm². 2 Na2SO4 with a concentration of 1500~3000 mg / L was added to the reactor as an electrolyte, the reaction temperature was 25±1℃, and the reaction time was 30~180 min.

[0018] Furthermore, the concentration of the modified activated carbon adsorbent is 0.5~1.25 g / L.

[0019] The present invention also provides a device for the synergistic treatment of new pollutants by multi-source catalytic coupling adsorption, including a reactor, a partition plate is provided at the bottom of the reactor, an anode and a cathode are fixedly arranged above the partition plate inside the reactor, the anode and cathode are respectively connected to the positive and negative terminals of a power supply located outside the reactor, and a modified activated carbon adsorption packing is supported on the partition plate. The modified activated carbon adsorption packing is granular activated carbon modified by impregnation with a mixed solution composed of iron salt, copper salt, cerium salt and graphene oxide.

[0020] Furthermore, the reactor is provided with an aeration port, an inlet, and an outlet from bottom to top. The aeration port is located below the partition, while the inlet and outlet are located above the partition. The inlet is connected to the wastewater inlet tank through a first external pipe, and a peristaltic pump is provided between the two. The outlet recycles the treated wastewater into the inlet tank through a second external pipe. The aeration port is connected to the aeration pump through a third external pipe. The height of the inlet tank is lower than that of the outlet.

[0021] Beneficial effects

[0022] This invention utilizes ternary metal / graphene oxide to modify granular activated carbon. After being modified by impregnation with ternary metal salts, the positively charged metal ions on the activated carbon particles exhibit strong electrophilicity. Modifying activated carbon with ternary metal ions effectively alters its physical properties, increasing the density of electrophilic sites on the activated carbon surface, thereby achieving efficient adsorption and capture of various novel pollutants. Furthermore, the activated carbon loaded with transition / rare earth metal ions acts as a catalyst, significantly improving the mass transfer efficiency and contact reaction time between novel pollutants and the activated carbon particle electrodes and metal electrodes. This facilitates the direct oxidation of novel pollutants by the granular activated carbon particle electrodes and metal electrodes in the 3D reaction system, improving the synergistic degradation rate of novel pollutants in traditional 3D electrochemical reaction systems. Simultaneously, the addition of rare earth metals allows for better dispersion of ternary metal oxide aggregates in the system, providing more active sites for the reaction and enhancing the oxidative degradation efficiency of the electrochemical electrodes for various novel pollutants. The addition of graphene oxide further enhances the conductivity of the granular activated carbon particle electrode. High conductivity can reduce the electron transport resistance in the reaction system, promote the transfer of electrons in the reaction system, and enhance the catalytic efficiency of the supported ternary metal oxide.

[0023] In practical operation, an electrochemical oxidation reaction occurs near the anode, where some negatively charged pollutants are adsorbed onto the anode electrode surface and directly oxidized and degraded; water is oxidized to produce H₂. + and e - Then at the cathode H + and e - The pollutants are reduced to H₂O₂, and some positively charged pollutants are adsorbed onto the cathode electrode surface and reduced. The redox reaction of the electrode can directly degrade and remove some COD and pollutants from the wastewater. The activated carbon particles filled between the cathode and anode act as polarized particle electrodes in the electric field. On the surface of the activated carbon particle electrodes, O₂ is effectively reduced to H₂O₂ through the 2e-ORR mechanism, and then catalyzed to generate ·OH, which has strong oxidizing properties. This is used for further oxidation of intermediate products of new pollutant degradation, ultimately enhancing the degradation of new pollutants in the wastewater.

[0024] This invention mainly utilizes direct electrode oxidation and catalytic generation of reactive oxygen free radicals to achieve efficient degradation of new pollutants. After the new pollutants adsorbed onto the surface of the modified activated carbon packing are further oxidized and degraded, the activated carbon packing can be electrochemically regenerated, increasing the adsorption threshold of the activated carbon packing for new pollutants, achieving simultaneous and efficient removal of multiple types of new pollutants, extending the service life of activated carbon granular packing, reducing the frequency of packing replacement, and effectively saving operating costs.

[0025] The cathode and anode of this invention are both annular mesh metal electrodes. When the two annular electrodes are placed in parallel within a limited device space, they have a larger reaction area compared to flat plates. At the same time, the mesh-like hollow design of the electrodes can increase the contact surface area between pollutants in the wastewater and the electrodes during the reaction process, effectively enhancing mass transfer efficiency, greatly reducing the current density during normal operation of the device, reducing the concentration of activated carbon added, achieving low power consumption operation, effectively controlling operating costs, and the treatment device is simple to operate and has good application prospects. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of a device for the synergistic treatment of novel pollutants by multi-source catalytic coupling adsorption according to the present invention;

[0027] Figure 2 The Langmuir and Freundlich adsorption models for FeCuCeGO / GAC of this invention are provided.

[0028] Figure 3 The effect of FeCuCeGO / GAC dosage on the adsorption effect of PFOA in this invention;

[0029] Figure 4 (a) and Figure 4 (b) consists of SEM images of the GAC from different angles; Figure 4 (c) Figure 4 (d) Figure 4 (e) and Figure 4 (f) shows SEM images of FeCuCeGO / GAC from different angles in Example 5; Figure 4 (g) is the EDS spectrum of FeCuCeGO / GAC in Example 5;

[0030] Figure 5 (a) is the N2 adsorption-desorption isotherm of FeCuCeGO / GAC in Example 5; Figure 5 (b) shows the pore size distribution of FeCuCeGO / GAC in Example 5;

[0031] Figure 6 Infrared spectra of GAC and FeCuCeGO / GAC in Example 5;

[0032] Figure 7 (a) Partial XRD pattern of GAC; Figure 7 (b) is the XRD pattern of FeCuCeGO / GAC in Example 5;

[0033] Figure 8 The removal efficiency of PFOA by a multi-source catalytic coupling adsorption system under different current densities was investigated.

[0034] Explanation of reference numerals in the attached drawings: 1. Reactor; 2. Inlet tank; 3. Peristaltic pump; 4. Annular mesh metal cathode; 5. Annular mesh metal anode; 6. Modified activated carbon adsorption packing; 7. Baffle plate; 8. Aeration pump. Detailed Implementation

[0035] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to illustrate the technical solution of the present invention more clearly, and should not be used to limit the scope of protection of the present invention.

[0036] This invention provides a method for the synergistic treatment of novel pollutants through multi-source catalytic coupling adsorption, comprising the following steps:

[0037] Graphene oxide is dispersed in an aqueous solution, and then iron salt, copper salt, and cerium salt are added to dissolve them, resulting in a mixed solution.

[0038] Pretreated granular activated carbon is impregnated in a mixed solution, stirred, filtered, dried, and then calcined. Finally, it is cooled and washed to obtain modified activated carbon adsorption filler.

[0039] The modified activated carbon adsorption packing is placed in a reactor containing an anode and a cathode;

[0040] Electrolytes are added to the reactor, wastewater containing new pollutants is introduced into the reactor, electricity is applied and the current density is controlled to a preset value to complete the pollutant treatment; wherein, the new pollutants include perfluorooctanoic acid, tributyl phosphate and tris(2-chloroethyl) phosphate.

[0041] In this embodiment, the iron salt, copper salt, and cerium salt are FeCl3, CuCl2·2H2O, and CeCl3, respectively, and the molar ratio of FeCl3, CuCl2·2H2O, and CeCl3 is (0.005~0.03): (0.01~0.02): (0.01~0.02).

[0042] In this embodiment, the ratio of the mass of the graphene oxide to the total mass of the iron salt, copper salt, and cerium salt is 0.2:(0.8~3), and the number of layers of the graphene oxide is less than 10.

[0043] In this embodiment, the pretreatment method includes: selecting 8-30 mesh granular activated carbon, first washing it with deionized water, then washing it with anhydrous ethanol, then placing it in an ultrasonic cleaner for 20-40 minutes, then immersing it in a water bath at 75-85°C for 5-15 minutes, and finally drying it in an oven at 55-65°C for 10-14 hours for later use.

[0044] In this embodiment, the calcination conditions are as follows: under a nitrogen atmosphere, in a vacuum box furnace, the temperature is increased to 700-900℃ at a rate of 5-10℃ / min and calcined for 2-4 hours.

[0045] In this embodiment, both the cathode and the anode are annular mesh metal electrodes. The anode and the cathode are respectively positioned close to the inner wall and the middle of the reactor and are arranged in parallel at the same height, with a spacing of 0.8~8cm between them.

[0046] In this embodiment, when wastewater containing new pollutants is introduced into the reactor, the initial pH is adjusted to 4.5-5.5; the preset value of the current density is 1-5 mA / cm². 2 Na2SO4 with a concentration of 1500~3000 mg / L was added to the reactor as an electrolyte, the reaction temperature was 25±1℃, and the reaction time was 30~180 min.

[0047] In this embodiment, the concentration of the modified activated carbon adsorption packing is 0.5~1.25 g / L.

[0048] This invention also provides a device for the synergistic treatment of new pollutants by multi-source catalytic coupling adsorption, including a reactor 1. A partition is provided at the bottom of the reactor 1. An anode and a cathode are fixed inside the reactor 1 and located above the partition. The anode and cathode are respectively connected to the positive and negative terminals of a power supply located outside the reactor 1. A modified activated carbon adsorption packing is supported on the partition. The modified activated carbon adsorption packing is granular activated carbon modified by impregnation with a mixed solution composed of iron salt, copper salt, cerium salt and graphene oxide.

[0049] In this embodiment, the reactor 1 is provided with an aeration port, an inlet, and an outlet from bottom to top. The aeration port is located below the partition plate, while the inlet and outlet are located above the partition plate. The inlet is connected to the wastewater inlet tank 2 through a first external pipe, and a peristaltic pump 3 is provided between the two. The outlet recycles the treated wastewater into the inlet tank 2 through a second external pipe. The aeration port is connected to the aeration pump 8 through a third external pipe. The height of the inlet tank 2 is lower than that of the outlet.

[0050] The modified activated carbon adsorption packing in this device contains positively charged transition / rare earth metal ions with strong electrophilicity. Modifying activated carbon with ternary metal ions effectively alters its physical properties, increasing the density of electrophilic sites on the activated carbon surface. This significantly increases the number of adsorption sites on the activated carbon packing, enabling highly efficient adsorption of new pollutants. Connecting the anode and cathode to an adjustable DC regulated power supply causes an electrochemical oxidation reaction near the anode. Some negatively charged pollutants are adsorbed onto the anode electrode surface and directly oxidized and degraded. Simultaneously, water is oxidized by the anode electrode to produce H₂. + and e - Then at the cathode H + and e- The pollutants are reduced to H₂O₂, and some positively charged pollutants are adsorbed onto the surface of the cathode electrode and reduced. The activated carbon particles filling the space between the cathode and anode act as polarized particle electrodes in the electric field, enabling efficient adsorption and capture of new pollutants in wastewater. The captured pollutants are then directly oxidized and converted to hydrogen sulfide (H₂O₂). - The ORR mechanism effectively reduces O2 to H2O2, catalyzing the generation of highly oxidizing ·OH, which can be further used for the degradation of new pollutants. Simultaneously, the addition of graphene oxide significantly improves the conductivity of the granular activated carbon particle electrode. High conductivity reduces electron transport resistance in the reaction system, promotes electron transfer, enhances the catalytic efficiency of the supported ternary metal oxide, and effectively improves the overall removal efficiency of new pollutants. The device is equipped with an aeration valve and aeration head at the bottom. The agitation of pollutants in the wastewater by microbubbles increases the contact rate with the activated carbon, enhancing the adsorption and degradation effects of the activated carbon.

[0051] Specifically, Figure 1 This invention discloses a device for the synergistic treatment of novel pollutants through multi-source catalytic coupling adsorption, comprising a reactor 1. The reactor 1 contains an anode, a cathode, and modified activated carbon adsorption packing material. The reactor 1 is a cylindrical device with an inlet and an outlet on its side. The anode is a ring-shaped mesh metal anode 5, connected to the positive terminal of an adjustable DC regulated power supply by a wire. The cathode is a ring-shaped mesh metal cathode 4, connected to the negative terminal of the adjustable DC regulated power supply by a wire. A partition 7 is located at the bottom of the reactor 1, supporting the modified activated carbon adsorption packing material 6. The modified activated carbon adsorption packing material 6 is composed of granular activated carbon impregnated and modified with a mixed solution of FeCl3, CuCl2·2H2O, CeCl3, and graphene oxide (GO), filling the space between the anode and cathode electrodes. The ring-shaped mesh metal anode 5 and the ring-shaped mesh metal cathode 4 in the reactor 1 are arranged in parallel at the same height, with a distance of 0.8–8 cm between the two electrodes. The current density during the reaction is set to 1–5 mA / cm². 2 The modified activated carbon adsorption packing 6 was added at a concentration of 0.5~1.25 g / L. After the reaction started, the actual wastewater containing new pollutants was pumped into the reaction device, the positive and negative electrodes were energized, the aeration pump 8 was turned on, and the reaction time was 30~180 min. The pollutants in the effluent of the device were sampled and detected at fixed time points.

[0052] Example 1

[0053] Preparation of modified activated carbon adsorption filler FeCuCeGO / GAC:

[0054] Graphene oxide was dispersed in 100 mL of aqueous solution, and FeCl3, CuCl2·2H2O, and CeCl3 were added to dissolve them, resulting in a mixed solution. The molar ratio of FeCl3, CuCl2·2H2O, and CeCl3 was 0.005:0.01:0.01, and the mass ratio of graphene oxide to the total mass of FeCl3, CuCl2·2H2O, and CeCl3 was 0.2:3.

[0055] Select 8-30 mesh granular activated carbon, first wash it with deionized water, then wash it with anhydrous ethanol, then place it in an ultrasonic cleaner and sonicate it for 30 minutes, then heat it in a water bath to 80℃ and soak it for 10 minutes, and finally dry it in an oven at 60℃ for 12 hours for later use.

[0056] 5g of granular activated carbon was impregnated in the above mixed solution, thoroughly mixed and stirred for 12h, filtered, and dried in an oven at 105℃ for 6h. The sample was then heated to 800℃ at 10℃ / min in a vacuum box furnace under nitrogen protection and maintained for 3h. After cooling to room temperature, it was washed multiple times with deionized water and ethanol and dried in an oven to obtain the modified activated carbon adsorption filler FeCuCeGO / GAC.

[0057] An experiment was conducted using 8L of combined wastewater from a wastewater treatment plant in an industrial park. The experiment was carried out in a 10L plexiglass column. A certain concentration (2000mg / L) of Na2SO4 electrolyte was added. Before the reaction, 1g / L of FeCuCeGO / GAC was added. The initial pH of the reaction solution was adjusted to approximately 5 using 0.1M H2SO4 and NaOH, and the experimental current density was set to 1mA / cm². 2 All experiments were conducted at room temperature (25 ± 1 °C). After setting the experimental parameters, the experiment was performed in constant flow mode for 180 minutes, with samples collected every 30 minutes. After sampling, the samples were filtered through a 0.22 μm filter membrane into liquid chromatography vials, and the concentration of new pollutants was determined by high-performance liquid chromatography-mass spectrometry.

[0058] Example 2

[0059] The only difference between this embodiment and Embodiment 1 is that the molar ratio of FeCl3, CuCl2·2H2O and CeCl3 is 0.005:0.01:0.01, and the mass ratio of graphene oxide to the total mass of FeCl3, CuCl2·2H2O and CeCl3 is 0.2:0.8.

[0060] Example 3

[0061] The only difference between this embodiment and Embodiment 1 is that the molar ratio of FeCl3, CuCl2·2H2O and CeCl3 is 0.02:0.01:0.01, and the mass ratio of graphene oxide to the total mass of FeCl3, CuCl2·2H2O and CeCl3 is 0.2:3.

[0062] Example 4

[0063] The only difference between this embodiment and Embodiment 1 is that the molar ratio of FeCl3, CuCl2·2H2O and CeCl3 is 0.02:0.01:0.01, and the mass ratio of graphene oxide to the total mass of FeCl3, CuCl2·2H2O and CeCl3 is 0.2:0.8.

[0064] Example 5

[0065] The only difference between this embodiment and Embodiment 1 is that the molar ratio of FeCl3, CuCl2·2H2O and CeCl3 is 0.02:0.015:0.015, and the mass ratio of graphene oxide to the total mass of FeCl3, CuCl2·2H2O and CeCl3 is 0.2:3.

[0066] Example 6

[0067] The only difference between this embodiment and Embodiment 1 is that the molar ratio of FeCl3, CuCl2·2H2O and CeCl3 is 0.02:0.015:0.015, and the mass ratio of graphene oxide to the total mass of FeCl3, CuCl2·2H2O and CeCl3 is 0.2:0.8.

[0068] Example 7

[0069] The only difference between this embodiment and Embodiment 1 is that the molar ratio of FeCl3, CuCl2·2H2O and CeCl3 is 0.03:0.02:0.02, and the mass ratio of graphene oxide to the total mass of FeCl3, CuCl2·2H2O and CeCl3 is 0.2:3.

[0070] Example 8

[0071] The only difference between this embodiment and Embodiment 1 is that the molar ratio of FeCl3, CuCl2·2H2O and CeCl3 is 0.03:0.02:0.02, and the mass ratio of graphene oxide to the total mass of FeCl3, CuCl2·2H2O and CeCl3 is 0.2:0.8.

[0072] Comparative Example 1

[0073] An experiment was conducted using 8L of combined wastewater from a wastewater treatment plant in an industrial park. The experiment was carried out in a 10L plexiglass column. A certain concentration (2000mg / L) of Na2SO4 electrolyte was added. Before the reaction, 1g / L of unmodified granular activated carbon was added. The initial pH of the reaction solution was adjusted to approximately 5 using 0.1M H2SO4 and NaOH, and the experimental current density was set to 1mA / cm². 2 All experiments were conducted at room temperature (25 ± 1 °C). After setting the experimental parameters, the experiment was performed in constant flow mode for 180 minutes, with samples collected every 30 minutes. After sampling, the samples were filtered through a 0.22 μm filter membrane into liquid chromatography vials, and the concentration of new pollutants was determined by high-performance liquid chromatography-mass spectrometry.

[0074] Comparative Example 2-1

[0075] The only difference between this comparative example and Example 1 is that FeCl3 was dissolved in 100 mL of water to obtain a mixed solution, and the molar concentration of FeCl3 was 0.02 mol / L.

[0076] Comparative Example 2-2

[0077] The only difference between this comparative example and Example 1 is that CuCl2·2H2O was dissolved in 100 mL of water to obtain a mixed solution, and the molar concentration of CuCl2·2H2O was 0.015 mol / L.

[0078] Comparative Examples 2-3

[0079] The only difference between this comparative example and Example 1 is that CeCl3 was dissolved in 100 mL of water to obtain a mixed solution, and the molar concentration of CeCl3 was 0.015 mol / L.

[0080] Comparative Example 3-1

[0081] The only difference between this comparative example and Example 1 is that FeCl3 and CuCl2·2H2O were dissolved in 100 mL of water to obtain a mixed solution, and the molar ratio of FeCl3 to CuCl2·2H2O was 0.02:0.015.

[0082] Comparative Example 3-2

[0083] The only difference between this comparative example and Example 1 is that FeCl3 and CeCl3 were dissolved in 100 mL of water to obtain a mixed solution, and the molar ratio of FeCl3 to CeCl3 was 0.02:0.015.

[0084] Comparative Example 3-3

[0085] The only difference between this comparative example and Example 1 is that CuCl2·2H2O and CeCl3 were dissolved in 100 mL of water to obtain a mixed solution, wherein the molar ratio of CuCl2·2H2O and CeCl3 was 0.015:0.015.

[0086] Comparative Example 4

[0087] The only difference between this comparative example and Example 1 is that FeCl3, CuCl2·2H2O and CeCl3 were dissolved in 100 mL of water to obtain a mixed solution; wherein the molar ratio of FeCl3, CuCl2·2H2O and CeCl3 was 0.02:0.015:0.015.

[0088] Experimental results

[0089] (1) Actual treatment effect of new pollutants in wastewater

[0090] The experimental results show that the raw wastewater in Comparative Example 1 mainly contained new pollutants such as PFOA, tributyl phosphate (TBP), and tris(2-chloroethyl) phosphate (TCEP), with concentrations ranging from 100 μg / L to 10 mg / L. Under conditions of low current and low activated carbon dosage, the 3D electrochemical device without modified activated carbon showed low removal efficiency for these new pollutants, with removal rates of only 39.56%, 43.37%, and 41.63% for PFOA, TBP, and TCEP, respectively.

[0091] The experimental results show that, compared with the unmodified activated carbon adsorption device, the adsorption device with monovalent modified activated carbon slightly improved the removal efficiency of new pollutants in Comparative Examples 2-1 to 2-3. The removal rates of PFOA, TBP and TCEP were 47.62%, 51.53% and 53.37% in Comparative Example 2-1; 45.38%, 50.26% and 54.61% in Comparative Example 2-2; and 49.55%, 49.76% and 52.08% in Comparative Example 2-3.

[0092] The experimental results show that, compared with the mono-modified activated carbon adsorption device, the binary modified activated carbon adsorption device also improved the removal efficiency of new pollutants in Comparative Examples 3-1 to 3-3. The removal rates of PFOA, TBP and TCEP were 58.66%, 60.19% and 62.57% in Comparative Example 3-1; 59.32%, 63.53% and 65.82% in Comparative Example 3-2; and 57.26%, 62.28% and 60.85% in Comparative Example 3-3.

[0093] The experimental results show that, compared with the binary modified activated carbon adsorption device, the ternary modified activated carbon adsorption device in Comparative Example 4 has a certain improvement in the removal efficiency of new pollutants, with removal rates of 69.17%, 73.16% and 71.26% for PFOA, TBP and TCEP, respectively.

[0094] The experimental results show that, compared with the ternary modified activated carbon adsorption device in Example 1, the ternary metal / graphene oxide modified activated carbon adsorption device significantly improves the removal efficiency of new pollutants. The removal rates of PFOA, TBP, and TCEP in Example 1 are 85.92%, 87.59%, and 90.72%, respectively; in Example 2, they are 87.28%, 89.63%, and 92.39%; in Example 3, they are 86.59%, 90.26%, and 92.37%; in Example 4, they are 88.16%, 91.32%, and 92.86%; in Example 5, they are 91.17%, 96.14%, and 99.26%; in Example 6, they are 92.66%, 97.29%, and 99.76%; in Example 7, they are 92.19%, 97.58%, and 99.36%; and in Example 8, they are 93.08%, 98.36%, and 99.82%.

[0095] The above results demonstrate that, compared with unmodified and mono-, binary, and ternary metal-modified granular activated carbon, ternary metal / graphene-modified granular activated carbon can significantly improve the efficient and synergistic removal of various typical new pollutants by a three-dimensional electrochemical system through the coupling of redox and efficient adsorption, as well as the enhancement of conductivity and catalytic performance after the addition of graphene oxide.

[0096] (2) Adsorption performance

[0097] To verify the adsorption performance of modified activated carbon adsorption packing for new pollutants and to explore whether it conforms to the Langmuir and Freundlich adsorption models, an adsorption isotherm study of PFOA was conducted using modified FeCuCeGO / GAC material (FeCuCeGO / GAC material in Example 5). Figure 2 This indicates that the adsorption of PFOA by FeCuCeGO / GAC is more consistent with the Langmuir adsorption model (R). 2The value was 0.99, indicating that monolayer adsorption played a dominant role in the adsorption process. Table 1 shows that the maximum theoretical adsorption capacity of FeCuCeGO / GAC for PFOA, obtained by fitting the Langmuir model, was 320.2 mg / g, while the maximum theoretical adsorption capacity of unmodified activated carbon for PFOA was only 16.4 mg / g. The adsorption capacity of modified activated carbon for typical new pollutants was nearly 20 times higher than that of unmodified activated carbon, indicating that the modification of activated carbon with ternary metal / graphene oxide (FeCuCeGO / GAC) can effectively increase the density of potential sites on the surface of activated carbon, greatly improving the adsorption capacity for new pollutants.

[0098] Table 1: Langmuir and Freundlich adsorption model parameters for FeCuCeGO / GAC

[0099]

[0100] FeCuCeGO / GAC was added to the system of Example 5 at concentrations of 0.25 g / L, 0.5 g / L, 0.75 g / L, 1 g / L, and 1.25 g / L, respectively, to investigate the effect of different adsorbent dosages on the adsorption of PFOA. Figure 3 The results showed that when the FeCuCeGO / GAC dosage was 0.25 g / L, 0.5 g / L, 0.75 g / L, 1 g / L, and 1.25 g / L, the PFOA removal rates after the reaction were 65.21%, 78.72%, 81.89%, 96.14%, and 99.89%, respectively. When the solution concentration remained constant, increasing the dosage of modified activated carbon meant increasing the total surface area of ​​the adsorbent, thus providing more adsorption sites and improving the removal rate and adsorption rate of pollutants. When the dosage of modified adsorbent was 1 g / L, PFOA in the solution could be essentially removed.

[0101] (3) Morphology and parameters

[0102] The morphology of the granular activated carbon before and after modification (FeCuCeGO / GAC material in Example 5) was characterized by SEM. Since the activated carbon solid particles were large and not uniform, they were scanned from multiple angles. Figure 4 (a) Figure 4 (b) shows that the original activated carbon surface is irregular but relatively smooth, with some fragments and slight pores, and no impurities. Figure 4 (c) Figure 4 (d) indicates that the modified activated carbon surface exhibits an irregular granular morphology, forming clear pores and many irregular bumps. Figure 4 (e) Figure 4(f) shows that the activated carbon surface is loaded with many microspheres of different shapes. These microspheres are likely metal oxide crystals of transition metals (Fe, Cu, Ce) generated during the loading process. Furthermore, combined with the EDS spectra, from... Figure 4 (g) Analysis shows that the prepared modified activated carbon is mainly composed of C, O, Fe, Cu and Ce elements, which are uniformly distributed on the activated carbon substrate, which is consistent with the SEM results.

[0103] By performing BET characterization on the activated carbon before and after modification using a specific surface area and pore size analyzer (FeCuCeGO / GAC material in Example 5), the pore structure and surface changes of the activated carbon before and after modification can be reflected. Figure 5 The results show that the N2 adsorption-desorption isotherms of the activated carbon before and after modification exhibit typical type IV curves in the high-pressure region, and the curves also contain H4 hysteresis phenomena with slit-like pores, indicating the presence of mesoporous structures. Table 2 shows that the BET specific surface area of ​​FeCuCeGO / GAC is 1019.98 m². 2 / g, with an average pore size of 3.37nm. The specific surface area of ​​the activated carbon before and after modification increased by 89 m². 2 The pore size increased from approximately 2.97 nm to 3.37 nm per gram. This is likely due to the heating of the activated carbon material at 800℃ for 3 hours during the modification process. This high-temperature treatment reduces impurities in the activated carbon pores, opening or expanding the pores and increasing the mesopore volume. This optimization of the pore structure leads to a larger specific surface area of ​​the activated carbon. Therefore, the deposition of metal oxides on the activated carbon surface did not clog the mesopores with pore sizes of 2-50 nm; instead, it promoted the formation of both mesopores and macropores.

[0104] Table 2: Surface physical properties of FeCuCeGO / GAC

[0105]

[0106] Fourier transform infrared spectroscopy was used to scan the surface of activated carbon before and after modification (FeCuCeGO / GAC material in Example 5) to analyze and identify the functional groups present on the surface of the adsorbent. Figure 6 This indicates that in the range of 400 to 4000 cm -1 In the FTIR spectra, the same peaks were observed in both types of activated carbon before and after modification. Both adsorbents showed peaks around 3430 cm⁻¹. -1 A vibrational stretching peak is observed at 1580 cm⁻¹, corresponding to surface phenolic hydroxyl groups (OH, -COOH) or the OH bonds of H₂O. -1 The peak is attributed to the C=C stretching vibration of the aromatic ring, 1090 cm⁻¹ -1This represents the aromatic skeleton in carbonaceous materials. Compared to GAC, the FTIR spectrum of modified GAC shows an increase in the 570-590 cm⁻¹ range. -1 A distinct absorption peak appears between 400 and 700 cm⁻¹, which may be due to the magnetic Fe-O bending vibration. Additionally, there is an absorption peak at 400-700 cm⁻¹. -1 Complex banding was observed in FeCuCeGO / GAC, attributed to vibrations of the metallic oxygen, indicating that vacancies on or within the GAC surface are occupied by metallic or half-metallic centers, for example, at 490 cm⁻¹. -1 An absorption peak generated by Ce-O stretching vibration appears nearby.

[0107] X-ray diffraction analysis was used to determine the phase composition, crystal structure and grain size of the material, and to compare the differences between the granular activated carbon before and after modification (FeCuCeGO / GAC material in Example 5). Figure 7 The XRD pattern of GAC shows a broad peak, with a characteristic diffraction peak of carbon observed at 2θ = 26.5°. For the FeCuCeGO / GAC adsorbent, new characteristic peaks appeared in the XRD pattern, with characteristic peaks at 2θ = 28.8°, 33.3°, 47.6°, 56.5°, and 69.6°, corresponding to the (111), (200), (220), (311), and (400) crystal planes on the CeO2 standard card, respectively, indicating that cerium dioxide is loaded on the surface of the activated carbon. At the same time, the phase analysis also found substances related to Fe3O4 and CuFe2O4. Since Fe3O4 and CuFe2O4 have almost the same inverse spinel crystal structure, except for the Fe in the octahedral interstices of Fe3O4, 2+ Cu in CuFe2O4 2+ The ions differ, therefore the characteristic peaks appearing at 2θ = 30.2°, 35.6°, 53.7°, and 74.3° correspond to the (220), (311), (422), and (533) crystal planes on the CuFe2O4 standard card, respectively, while the peak at 2θ = 62.6° corresponds to the (440) crystal plane of Fe3O4. These peaks match the peaks of CuFe2O4 and Fe3O4, indicating that the substance is loaded on the activated carbon substrate. In addition, the peaks at 2θ = 43.4°, 50.5°, and 74.3° correspond to the Cu (111), (200), and (220) crystal planes, indicating the presence of zero-valent Cu on the activated carbon.

[0108] (4) Implementation parameters

[0109] The difference compared to Example 5 lies in setting multiple current densities (1, 2, 3, 4, 5 mA / cm²). 2 The remaining operations and conditions are the same as in Example 5. Figure 8 The display shows that when the current density is 1 mA / cm²2 At that time, the degradation rate constant of PFOA by catalytic oxidation coupled adsorption was higher than that at a current density of 4 mA / cm². 2 and 5mA / cm 2 The degradation rate constant at a current density of 2 mA / cm² 2 and 3mA / cm 2 The degradation rate constants did not differ significantly over time, which may be due to the enhanced hydrogen evolution reaction caused by increased voltage, while the oxygen evolution side reaction reduced the utilization efficiency of hydroxyl radicals, thus making the degradation effect less significant. Furthermore, when the current density was 1 mA / cm²... 2 At this time, the cooperative effect constant of the reaction system is the highest. Considering the economy of the reaction, 1 mA / cm² is selected. 2 As a current density parameter of the reaction system, it shows that the multi-source catalytic coupling adsorption system constructed in this invention can achieve efficient degradation of PFOA under low current density conditions, and has good application prospects.

[0110] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the inventive technical essence shall still fall within the protection scope of the present invention.

Claims

1. A method for the synergistic treatment of novel pollutants through multi-source catalytic coupling adsorption, characterized in that, The steps are as follows: Graphene oxide is dispersed in an aqueous solution, and then iron salt, copper salt, and cerium salt are added to dissolve them, resulting in a mixed solution. Pretreated granular activated carbon is impregnated in a mixed solution, stirred, filtered, dried, and then calcined. Finally, it is cooled and washed to obtain modified activated carbon adsorption filler. The modified activated carbon adsorption packing is placed in a reactor containing an anode and a cathode; Electrolytes are added to the reactor, wastewater containing new pollutants is introduced into the reactor, electricity is applied and the current density is controlled to a preset value to complete the pollutant treatment; wherein, the new pollutants include perfluorooctanoic acid, tributyl phosphate and tris(2-chloroethyl) phosphate; The iron salt, copper salt, and cerium salt are FeCl3, CuCl2·2H2O, and CeCl3, respectively, and the molar ratio of FeCl3, CuCl2·2H2O, and CeCl3 is 0.005~0.03: 0.01~0.02: 0.01~0.

02. The mass ratio of the graphene oxide to the total mass of the iron salt, copper salt, and cerium salt is 0.2:0.8~3, and the number of graphene oxide layers is less than 10. The pretreatment method is as follows: Select 8-30 mesh granular activated carbon, first wash it with deionized water, then wash it with anhydrous ethanol, then put it into an ultrasonic cleaner and sonicate it for 20-40 minutes, then heat it in a water bath to 75-85℃ and soak it for 5-15 minutes, and finally dry it in an oven at 55-65℃ for 10-14 hours for later use. The calcination conditions are as follows: under a nitrogen atmosphere, in a vacuum box furnace, the temperature is increased to 700-900℃ at a rate of 5-10℃ / min and calcined for 2-4 hours. When introducing wastewater containing new pollutants into the reactor, adjust the initial pH to 4.5-5.5; the preset value for the current density is 1-5 mA / cm². 2 Na2SO4 with a concentration of 1500~3000 mg / L was added to the reactor as an electrolyte, the reaction temperature was 25±1℃, and the reaction time was 30~180 min. The concentration of the modified activated carbon adsorption packing is 1.0~1.25 g / L.

2. The method according to claim 1, characterized in that, Both the cathode and anode are annular mesh metal electrodes. The anode and cathode are respectively positioned near the inner wall and the middle of the reactor and are arranged in parallel at the same height, with a spacing of 0.8~8cm between them.

3. An apparatus for the multi-source catalytic coupling adsorption synergistic treatment of new pollutants using the method described in any one of claims 1-2, characterized in that, The reactor includes a baffle plate located at the bottom of the reactor. An anode and a cathode are fixed inside the reactor and located above the baffle plate. The anode and cathode are respectively connected to the positive and negative terminals of a power source located outside the reactor. The baffle plate supports a modified activated carbon adsorption packing material, which is granular activated carbon modified by impregnation with a mixed solution composed of iron salt, copper salt, cerium salt and graphene oxide.

4. The apparatus according to claim 3, characterized in that, The reactor is equipped with an aeration port, an inlet, and an outlet from bottom to top. The aeration port is located below the partition, while the inlet and outlet are located above the partition. The inlet is connected to the wastewater inlet tank through a first external pipe, and a peristaltic pump is installed between the two. The outlet recycles the treated wastewater into the inlet tank through a second external pipe. The aeration port is connected to the aeration pump through a third external pipe. The height of the inlet tank is lower than that of the outlet.

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