Method and device for synergistically treating new pollutants through multi-source catalysis coupling adsorption

Abstract

The invention discloses a method and device for synergistically treating new pollutants through multi-source catalysis coupling adsorption, and the method comprises the following steps: dispersing graphene oxide in an aqueous solution, then adding ferric salt, copper salt and cerium salt, and dissolving the ferric salt, the copper salt and the cerium salt to obtain a mixed solution; the preparation method comprises the following steps: dipping pretreated granular active carbon in a mixed solution, stirring, filtering, drying, calcining, and finally cooling and washing to obtain the modified active carbon adsorption filler, placing the modified activated carbon adsorption filler in a reactor comprising an anode and a cathode; the method comprises the following steps: adding electrolyte into a reactor, introducing wastewater containing new pollutants into the reactor, electrifying and controlling the current density to be a preset value to complete pollutant treatment; wherein the new pollutants comprise perfluorooctanoic acid, tributyl phosphate and tris (2-chloroethyl) phosphate. The method can achieve the synergistic treatment effect on various new pollutants, is easy to operate and low in operation cost, and has a good application prospect.

Description

Technical Field

[0001] The present invention belongs to the technical field of water pollution treatment, and in particular relates to a method and device for collaboratively treating new pollutants using multi-source catalytic coupled adsorption. Background Art

[0002] Currently, the four main emerging pollutants of concern include endocrine disruptors, perfluorinated compounds, microplastics, and antibiotics. While their overall concentrations in the environment are relatively low, they are stable, difficult to decompose, and easily accumulate. Long-term, low-dose exposure to these pollutants can pose significant risks to human health and the ecological environment.

[0003] Currently, numerous technologies for the removal of emerging pollutants have been reported, including biological methods, adsorption, chemical oxidation, membrane technology, and advanced oxidation processes. According to incomplete statistics, adsorption, photocatalytic oxidation, biological methods, and ozone oxidation are the four most widely studied removal technologies, accounting for approximately 66% of all removal technology research. Activated carbon is the most commonly used adsorbent in wastewater treatment, used to remove a variety of conventional pollutants as well as recalcitrant organic pollutants. The activated carbon adsorption process is influenced by many factors, including the activated carbon's inherent properties (such as the material, specific surface area, and surface chemistry); the physicochemical properties of the emerging pollutants (such as hydrophobicity, solubility, charge, and molecular size); the chemical properties and composition of the solution (such as soluble organic matter); and other essential parameters such as activated carbon dosage and adsorbate concentration. Based on practical experience, the main challenges of activated carbon adsorption in actual operation are competition for adsorption sites with other coexisting organic matter in the wastewater and reduced adsorption efficiency due to pore clogging. Furthermore, the adsorption process produces a large amount of carbonaceous sludge, which increases the energy consumption of sludge treatment.

[0004] Chinese patent CN117383665A discloses an iron / copper needle coke three-dimensional electric Fenton particle electrode and its preparation method. This method uses an impregnation calcination method to load copper onto the needle coke. Then, iron oxides, copper-modified needle coke, a binder, and anhydrous ethanol are mixed evenly. After compression molding, the mixture is calcined at high temperature under a nitrogen environment to obtain an iron / copper needle coke three-dimensional electric Fenton particle electrode. This method promotes the Fenton chain reaction through the binary metal-modified particle electrode, achieving the effect of efficient degradation of organic matter. This method can achieve a removal efficiency of more than 90% for conventional pollutants such as COD and ammonia nitrogen in landfill leachate. However, the required particle electrode dosage in the reaction system is 25g / L, which is costly for pollutant removal. The reaction time to achieve the optimal treatment effect is 6h, the system reaction efficiency is low, and this method only has a good removal effect on conventional pollutants in landfill leachate. The removal effect of new pollutants in wastewater has not been verified. It cannot meet the demand for the synergistic removal of multiple types of pollutants in actual wastewater, and its practical application advantages are not obvious. Summary of the Invention

[0005] In response to the shortcomings of the existing technology, the present invention provides a method and device for the synergistic treatment of new pollutants through multi-source catalytic coupled adsorption, which combines the efficient adsorption of modified activated carbon with electrochemical oxidation, greatly enhancing the degradation efficiency of traditional three-dimensional (3D) electrochemical reaction systems for new pollutants, overcoming the shortcomings of high treatment costs, low reaction efficiency, and poor synergistic removal of new pollutants.

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

[0007] The present invention provides a method for synergistically treating new pollutants by multi-source catalysis coupled adsorption, comprising the following steps:

[0008] Dispersing graphene oxide in an aqueous solution and then adding iron salt, copper salt, and cerium salt to dissolve the iron salt, copper salt, and cerium salt to obtain a mixed solution;

[0009] The pretreated granular activated carbon is immersed in the mixed solution, stirred, filtered, dried, and then calcined, and finally cooled and washed to obtain a modified activated carbon adsorption filler;

[0010] placing a modified activated carbon adsorbent filler in a reactor comprising an anode and a cathode;

[0011] Electrolytes are added to the reactor, wastewater containing new pollutants is introduced into the reactor, power is applied and the current density is controlled to a preset value to complete 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, the copper salt, and the 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, heating it to 75-85°C in a water bath and soaking it for 5-15 minutes, and finally drying it in an oven at 55-65°C for 10-14 hours for use.

[0015] Furthermore, the calcination treatment conditions are: under nitrogen atmosphere, in a vacuum box furnace, heating to 700-900° C. at a rate of 5-10° C. / min and calcining for 2-4 hours.

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

[0017] Furthermore, when the 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 / cm 2 ; Na2SO4 with a concentration of 1500~3000 mg / L is added to the reactor as an electrolyte, the reaction temperature is 25±1℃, and the reaction time is 30~180min.

[0018] Furthermore, the addition concentration of the modified activated carbon adsorption filler 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 coupled adsorption, comprising a reactor, a partition being provided at the lower interior of the reactor, an anode and a cathode being fixedly provided in the reactor and located above the partition, the anode and the cathode being respectively connected to the positive and negative poles of a power supply located outside the reactor, and a modified activated carbon adsorption filler being supported on the partition, wherein the modified activated carbon adsorption filler is granular activated carbon modified by impregnation with a mixed solution of iron salt, copper salt, cerium salt and graphene oxide.

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

[0021] Beneficial effects

[0022] The present invention utilizes ternary metal / graphene oxide to modify granular activated carbon. After the granular activated carbon as an adsorption carrier is modified by impregnation loading with ternary metal salts, the positively charged metal ions on the activated carbon particles have strong electrophilicity. Modifying the activated carbon with ternary metal ions can effectively change its physical properties and increase the density of electrophilic sites on the surface of the activated carbon material, thereby achieving efficient adsorption and capture of a variety of new pollutants. In addition, the activated carbon loaded with transition / rare earth metal ions can be used as a catalyst to greatly promote the mass transfer efficiency and contact reaction time of new pollutants with the activated carbon particle electrode and the metal electrode, which is conducive to the direct oxidation of new pollutants by the granular activated carbon particle electrode and the metal electrode in the 3D reaction system, thereby improving the synergistic degradation rate of the traditional 3D electrochemical reaction system for new pollutants. At the same time, by adding rare earth metals, the ternary metal oxide aggregates in the system can be better dispersed, providing more active sites for the reaction, and improving the oxidation and degradation efficiency of the electrochemical electrode for a variety of new pollutants. The addition of graphene oxide further improves the conductivity of the granular activated carbon particle electrode. The high conductivity can reduce the electron transfer resistance in the reaction system, promote the transfer of electrons in the reaction system, and enhance the catalytic efficiency of the loaded ternary metal oxide.

[0023] During the specific operation of the present invention, an electrochemical oxidation reaction occurs near the anode, and some negatively charged pollutants are adsorbed onto the surface of the anode electrode and directly oxidized and degraded; water is oxidized to produce H + and e - , then at the cathode H + and e - The oxygen is reduced to H2O2, and some positively charged pollutants are adsorbed and reduced on the cathode electrode surface. The redox reaction of the electrode directly degrades and removes some COD and pollutants in 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 electrode, O2 is effectively reduced to H2O2 through the 2e-ORR mechanism. This is then catalyzed to generate highly oxidizing ·OH, which is used to further oxidize the degradation intermediates of new pollutants, ultimately enhancing the degradation of new pollutants in the wastewater.

[0024] The present invention mainly utilizes direct oxidation of electrodes and catalytic generation of active oxygen free radicals to achieve efficient degradation of new pollutants. After the new pollutants adsorbed on the surface of the modified activated carbon filler are further oxidized and degraded, the electrochemical regeneration of the activated carbon filler can be achieved, thereby increasing the adsorption threshold of the activated carbon filler for new pollutants, achieving simultaneous and efficient removal of multiple types of new pollutants, extending the service life of the activated carbon particle filler, reducing the frequency of filler replacement, and effectively saving operating costs.

[0025] The cathode and the anode of the application are both annular net-shaped metal electrodes, which have larger reaction area compared with flat plate electrodes after the two annular electrodes are placed in parallel in limited device space, and the hollow design of the electrode net can increase the contact surface area of pollutants in wastewater and the electrode in the reaction process, effectively enhance the mass transfer efficiency, greatly reduce the current density during normal operation of the device, reduce the dosage concentration of activated carbon, realize low power consumption operation, effectively control the operation cost, and the treatment device is simple to operate and has good application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 It is a structural schematic diagram of a multi-source catalytic coupling adsorption collaborative governance new pollutant device of the application;

[0027] Figure 2 It is a Langmuir and Freundlich adsorption model of FeCuCeGO / GAC of the application;

[0028] Figure 3 It is the influence of the dosage of FeCuCeGO / GAC on the adsorption effect of PFOA;

[0029] Figure 4 (a) and Figure 4 (b) part is the SEM image of GAC at different angles; Figure 4 (c), Figure 4 (d), Figure 4 (e) and Figure 4 (f) part is the SEM image of FeCuCeGO / GAC at different angles in Example 5; Figure 4 (g) part is the EDS spectrum of FeCuCeGO / GAC in Example 5;

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

[0031] Figure 6 It is the infrared spectrum of GAC and FeCuCeGO / GAC in Example 5;

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

[0033] Figure 8 It is the removal effect of the multi-source catalytic coupling adsorption system on PFOA under different current densities;

[0034] Explanation of the accompanying symbols: 1. Reactor; 2. Water inlet tank; 3. Peristaltic pump; 4. Annular mesh metal cathode; 5. Annular mesh metal anode; 6. Modified activated carbon adsorption filler; 7. Partition; 8. Aeration pump. DETAILED DESCRIPTION

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

[0036] An embodiment of the present invention provides a method for synergistically treating new pollutants by multi-source catalysis coupled adsorption, comprising the following steps:

[0037] Dispersing graphene oxide in an aqueous solution and then adding iron salt, copper salt, and cerium salt to dissolve the iron salt, copper salt, and cerium salt to obtain a mixed solution;

[0038] The pretreated granular activated carbon is immersed in the mixed solution, stirred, filtered, dried, and then calcined, and finally cooled and washed to obtain a modified activated carbon adsorption filler;

[0039] placing a modified activated carbon adsorbent filler in a reactor comprising an anode and a cathode;

[0040] Electrolytes are added to the reactor, wastewater containing new pollutants is introduced into the reactor, power is applied and the current density is controlled to a preset value to complete 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, the copper salt, and the cerium salt is 0.2:(0.8-3), and the number of layers of the graphene oxide is 10 or less.

[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, and then placing it in an ultrasonic cleaner for 20-40 minutes, and heating it to 75-85°C in a water bath and soaking it for 5-15 minutes, and finally drying it in an oven at 55-65°C for 10-14 hours for use.

[0044] In this embodiment, the calcination treatment conditions are: in a nitrogen atmosphere, in a vacuum box furnace, heating to 700-900° C. at a rate of 5-10° C. / min and calcining for 2-4 hours.

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

[0046] In this embodiment, when the 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 / cm 2 ; Na2SO4 with a concentration of 1500~3000 mg / L is added to the reactor as an electrolyte, the reaction temperature is 25±1℃, and the reaction time is 30~180min.

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

[0048] An embodiment of the present invention also provides a device for synergistically treating new pollutants by multi-source catalytic coupled adsorption, comprising a reactor 1, a partition being provided at the lower interior of the reactor 1, an anode and a cathode being fixedly provided in the reactor 1 and located above the partition, the anode and the cathode being respectively connected to the positive and negative poles of a power supply located outside the reactor 1, a modified activated carbon adsorption filler being supported on the partition, the modified activated carbon adsorption filler being granular activated carbon modified by impregnation with a mixed solution of iron salt, copper salt, cerium salt and graphene oxide.

[0049] In this embodiment, the reactor 1 is provided with an aeration port, a water inlet and a water outlet from bottom to top. The aeration port is located below the partition and the water inlet and the water outlet are both located above the partition. The water inlet is connected to the water inlet pool 2 for storing wastewater through a first external pipe and a peristaltic pump 3 is provided between the two. The water outlet recycles the treated wastewater into the water inlet pool 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 water inlet pool 2 is lower than the water outlet.

[0050] The positively charged transition / rare earth metal ions in the modified activated carbon adsorption filler in this device have strong electrophilicity. Using ternary metal ions to modify activated carbon can effectively change its physical properties, increase the density of electrophilic sites on the surface of the activated carbon material, and greatly increase the adsorption sites of the activated carbon filler, which can achieve efficient adsorption of new pollutants. When the anode and cathode are connected to an adjustable DC regulated power supply, an electrochemical oxidation reaction occurs near the anode. Some negatively charged pollutants are adsorbed to the surface of the anode electrode and directly oxidized and degraded. At the same time, water is oxidized by the anode electrode to produce H + and e - , then at the cathode H + and e- The partially positively charged pollutants are adsorbed to the cathode electrode surface and reduced to H2O2. The activated carbon particles filled between the cathode and the anode can be used as polarized particle electrodes in the electric field, which can achieve efficient adsorption and capture of new pollutants in wastewater, direct oxidation of the captured new pollutants, and removal of the new pollutants through 2e - The ORR mechanism effectively reduces O2 to H2O2, and the catalytic generation of ·OH with strong oxidizing property can be further used for degradation of new pollutants. Meanwhile, the addition of graphene oxide can greatly improve the conductivity of the granular activated carbon particle electrode. High conductivity can reduce the electron transfer resistance in the reaction system, promote the transfer of electrons in the reaction system, enhance the catalytic efficiency of the loaded ternary metal oxide, and effectively improve the overall removal efficiency of new pollutants. The device is provided with an aeration valve and an aeration head at the bottom. The pollutants in the wastewater increase the contact rate with the activated carbon under the agitation of the micro-bubbles, and the adsorption and degradation effect of the activated carbon is enhanced.

[0051] Specifically, Figure 1 A device for multi-source catalytic coupling adsorption and synergistic treatment of new pollutants is shown, which comprises a reactor 1, an anode, a cathode and a modified activated carbon adsorption filler in the reactor 1, the reactor 1 is a cylindrical device, the reactor 1 is provided with a water inlet and a water outlet on the side, the anode is a ring-shaped net-shaped metal anode 5 connected to the positive electrode of an adjustable direct current stabilized power supply by a wire; the cathode is a ring-shaped net-shaped metal cathode 4 connected to the negative electrode of an adjustable direct current stabilized power supply by a wire, a partition plate 7 is arranged below the bottom of the reactor 1, the modified activated carbon adsorption filler 6 is supported on the partition plate 7, the modified activated carbon adsorption filler 6 is a granular activated carbon impregnated with a mixed solution of FeCl3, CuCl2·2H2O, CeCl3 and graphene oxide (GO) to load the modified adsorption filler, which is filled between the anode and the cathode electrode, the ring-shaped net-shaped metal anode 5 and the ring-shaped net-shaped metal cathode 4 in the reactor 1 are arranged in parallel at the same height, the distance between the two electrodes is 0.8-8 cm, and the current density is set to 1-5 mA / cm 2 The left and right sides, and the dosage concentration of the modified activated carbon adsorption filler 6 is 0.5-1.25 g / L. After the reaction starts, the actual wastewater containing new pollutants is pumped into the reaction device, the positive and negative electrodes are electrified, the aeration pump 8 is opened, the reaction time is 30-180 min, and the pollutants in the effluent of the device are 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 FeCl3, CuCl2﹒2H2O, and CeCl3 to obtain a mixed solution; wherein 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, wash it with deionized water first, then with anhydrous ethanol, then put it into an ultrasonic cleaner for 30 minutes, heat it to 80℃ in a water bath and soak it for 10 minutes, and finally dry it in an oven at 60℃ for 12 hours for use.

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

[0057] 8L of comprehensive wastewater from a sewage treatment plant in an industrial park was selected as the treatment object for the wastewater experiment. The experiment was carried out in a 10L organic glass column. A certain concentration (2000mg / L) of Na2SO4 electrolyte was added. 1g / L of FeCuCeGO / GAC was added before the reaction. The initial pH of the reaction solution was adjusted to about 5 using 0.1M H2SO4 and NaOH, and the experimental current density was set to 1mA / cm 2 All experiments were conducted at room temperature (25 ± 1°C). After setting the experimental parameters, a 180-minute experiment was performed in constant flow mode, with samples collected every 30 minutes. The samples were filtered through a 0.22 μm filter into a liquid chromatography vial, and the concentration of the new contaminants 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] 8L of comprehensive wastewater from a sewage treatment plant in an industrial park was selected as the treatment object for the wastewater experiment. The experiment was carried out in a 10L organic glass column. A certain concentration (2000mg / L) of Na2SO4 electrolyte was added. 1g / L of unmodified granular activated carbon was added before the reaction. The initial pH of the reaction solution was adjusted to about 5 using 0.1M H2SO4 and NaOH, and the experimental current density was set to 1mA / cm 2 All experiments were conducted at room temperature (25 ± 1°C). After setting the experimental parameters, a 180-minute experiment was performed in constant flow mode, with samples collected every 30 minutes. The samples were filtered through a 0.22 μm filter into a liquid chromatography vial, and the concentration of the new contaminants 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 is dissolved in 100 mL of water to obtain a mixed solution, and the molar concentration of FeCl3 is 0.02 mol / L.

[0076] Comparative Example 2-2

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

[0078] Comparative Examples 2-3

[0079] The only difference between this comparative example and Example 1 is that CeCl 3 is dissolved in 100 mL of water to obtain a mixed solution, and the molar concentration of CeCl 3 is 0.015 mol / L.

[0080] Comparative Example 3-1

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

[0082] Comparative Example 3-2

[0083] The difference between this comparative example and Example 1 is that FeCl3 and CeCl3 are dissolved in 100 mL of water to obtain a mixed solution, and the molar ratio of FeCl3 to CeCl3 is 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 are dissolved in 100 mL of water to obtain a mixed solution, wherein the molar ratio of CuCl2.2H2O to CeCl3 is 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 are dissolved in 100 mL of water to obtain a mixed solution; wherein the molar ratio of FeCl3, CuCl2﹒2H2O and CeCl3 is 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 main new pollutants detected in the comprehensive wastewater from Comparative Example 1 were PFOA, tributyl phosphate (TBP), and tris(2-chloroethyl) phosphate (TCEP), with concentrations ranging from 100 μg / L to 10 mg / L. Under low current and activated carbon dosage conditions, the 3D electrochemical device using unmodified activated carbon had low efficiency in removing new pollutants, achieving 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 in Comparative Examples 2-1 to Comparative Example 2-3, the adsorption device of the monolithic modified activated carbon has a slightly improved efficiency in removing new pollutants. The removal rates of PFOA, TBP and TCEP in Comparative Example 2-1 are 47.62%, 51.53% and 53.37%; in Comparative Example 2-2, they are 45.38%, 50.26% and 54.61%; and in Comparative Example 2-3, they are 49.55%, 49.76% and 52.08%.

[0092] It can be seen from the experimental results that compared with the one-component modified activated carbon adsorption device in Comparative Examples 3-1 to Comparative Example 3-3, the binary modified activated carbon adsorption device has improved the removal efficiency of new pollutants. The removal rates of PFOA, TBP and TCEP in Comparative Example 3-1 are 58.66%, 60.19% and 62.57%; in Comparative Example 3-2, they are 59.32%, 63.53% and 65.82%; and in Comparative Example 3-3, they are 57.26%, 62.28% and 60.85%.

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

[0094] From the experimental results, it can be seen that compared with the ternary modified activated carbon adsorption device in Example 1, the ternary metal / graphene oxide modified activated carbon adsorption device has a significantly improved efficiency in removing new pollutants. The removal rates of PFOA, TBP and TCEP in Example 1 are 85.92%, 87.59% and 90.72%; 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%; in Example 8, they are 93.08%, 98.36% and 99.82%.

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

[0096] (2) Adsorption performance

[0097] In order to verify the adsorption performance of modified activated carbon adsorption fillers for new pollutants and explore whether it conforms to the Langmuir and Freundlich adsorption models, the adsorption isotherm of PFOA was studied using modified FeCuCeGO / GAC materials (FeCuCeGO / GAC materials in Example 5). Figure 2 It shows that the adsorption of PFOA by FeCuCeGO / GAC is more consistent with the Langmuir adsorption model (R 2The adsorption capacity of FeCuCeGO / GAC for typical new pollutants is nearly 20 times higher than that of unmodified activated carbon, indicating that the use of ternary metal / graphene oxide loading modification (FeCuCeGO / GAC) can effectively increase the density of electrophilic sites on the activated carbon surface, significantly improving its adsorption capacity for new pollutants.

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

[0099]

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

[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 characterization. Since the solid particles of activated carbon were large and not uniform, they were scanned from multiple angles. Figure 4 (a) Figure 4 (b) shows that the surface of the original activated carbon is irregular but relatively smooth, contains some debris and is slightly porous, and contains no impurities. Figure 4 (c) Figure 4 (d) shows that the surface of the modified activated carbon exhibits an irregular granular morphology, forming clear pores and many irregular concave and convex points. Figure 4 (e) Figure 4(f) shows that the surface of activated carbon is loaded with many microspherical fine particles of different shapes. These fine particles may be metal oxide crystals of transition metals (Fe, Cu, Ce) produced during the loading process. In addition, combined with the EDS spectrum, 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] The BET characterization of the activated carbon before and after modification (FeCuCeGO / GAC material in Example 5) was performed using a specific surface area and pore size analyzer, which can reflect the pore structure and surface changes of the activated carbon before and after modification. Figure 5 It shows that the N2 adsorption-desorption isotherms of activated carbon before and after modification show a typical type IV curve in the high pressure region and the curve contains the H4 hysteresis phenomenon of slit-like pores, indicating the existence of mesoporous structure in its structure. Table 2 shows that the BET specific surface area of ​​FeCuCeGO / GAC is 1019.98m 2 / g, and the average pore size is 3.37nm. The specific surface area of ​​the activated carbon before and after modification increased by 89 m 2 / g, and the pore size increased from 2.97nm to 3.37nm. This may be due to the fact that during the activated carbon modification process, the activated carbon material is heated at 800℃ for 3 hours. The high temperature treatment reduces impurities in the activated carbon pores, opens or expands the pores of the activated carbon, and increases the mesopore volume of the material. This pore structure optimization increases the specific surface area of ​​the activated carbon. Therefore, the metal oxide deposition on the activated carbon surface does not block the mesopores with a pore size of 2-50nm, but instead promotes the formation of 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 the activated carbon before and after modification (FeCuCeGO / GAC material in Example 5) to analyze and identify the functional groups on the surface of the adsorbent. Figure 6 It shows that in the range of 400 to 4000 cm -1 In the FTIR spectra of the two activated carbons before and after modification, the same peak was observed. Both adsorbent materials showed a peak at 3430 cm -1 There is a vibration stretching peak at 1580 cm, which corresponds to the surface phenolic hydroxyl group (OH, -COOH) or the OH bond of H2O. -1 The peak at 1090 cm is attributed to the C=C stretching vibration of the aromatic ring. -1Compared with GAC, the FTIR spectrum of modified GAC shows that the FTIR spectrum of modified GAC is 570-590cm -1 There is an obvious absorption peak between 400-700cm -1 Complex bands were observed in FeCuCeGO / GAC, which were attributed to the vibration of metallic oxygen, indicating that the vacancies on the surface or inside of GAC were occupied by metallic or semimetallic centers, for example, at 490 cm -1 An absorption peak caused 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 (the FeCuCeGO / GAC material in Example 5). Figure 7 It shows that there are broad peaks in the XRD spectrum of GAC, and the characteristic diffraction peak of carbon is observed at 2θ=26.5°. For FeCuCeGO / GAC adsorbent, new characteristic peaks appear in the XRD spectrum. The characteristic peaks appearing at 2θ=28.8°, 33.3°, 47.6°, 56.5° and 69.6° correspond to the (111), (200), (220), (311) and (400) crystal planes on the CeO2 standard card, respectively, indicating that the surface of the activated carbon is loaded with cerium dioxide. At the same time, the phase detection also found that the substance is related to Fe3O4 and CuFe2O4. Since Fe3O4 and CuFe2O4 have almost the same trans-spinel crystal structure, except for the Fe in the octahedral gap of Fe3O4, the cerium dioxide in the octahedral gap of Fe3O4 is also found. 2+ and Cu in CuFe2O4 2+ There are differences in the ions, so the characteristic peaks 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, and 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 species on the activated carbon.

[0108] (4) Implementation parameters

[0109] Compared with Example 5, the difference is that various current densities (1, 2, 3, 4, 5 mA / cm 2 ), the remaining operations and conditions are the same as those in Example 5. Figure 8 It shows that when the current density is 1mA / cm2 When the catalytic oxidation coupled adsorption degradation rate constant of PFOA is higher than that of PFOA at a current density of 4 mA / cm 2 and 5mA / cm 2 The degradation rate constant at a current density of 2 mA / cm 2 and 3mA / cm 2 The degradation rate constants are not much different when the voltage is increased. This may be because the hydrogen evolution reaction is enhanced due to the increase in voltage, and the oxygen evolution side reaction reduces the utilization efficiency of hydroxyl radicals, making the degradation effect less obvious. And when the current density is 1mA / cm 2 The synergistic effect constant of the reaction system is the highest when 1 mA / cm 2 As the current density parameter of the reaction system, it is shown that the multi-source catalytic coupled adsorption system constructed in the present invention can achieve efficient degradation of PFOA under low current density conditions, and has good application prospects.

[0110] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent variation made to the above embodiment based on the essence of the invention technology shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A method for synergistic treatment of new pollutants by multi-source catalysis coupled adsorption, characterized in that: The following steps are involved: Dispersing graphene oxide in an aqueous solution and then adding iron salt, copper salt, and cerium salt to dissolve the iron salt, copper salt, and cerium salt to obtain a mixed solution; The pretreated granular activated carbon is immersed in the mixed solution, stirred, filtered, dried, and then calcined, and finally cooled and washed to obtain a modified activated carbon adsorption filler; placing a modified activated carbon adsorbent filler in a reactor comprising an anode and a cathode; Electrolytes are added to the reactor, wastewater containing new pollutants is introduced into the reactor, power is applied and the current density is controlled to a preset value to complete pollutant treatment; wherein the new pollutants include perfluorooctanoic acid, tributyl phosphate and tris(2-chloroethyl) phosphate.

2. The method according to claim 1, characterized in that 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).

3. The method according to claim 1, characterized in that The ratio of the mass of the graphene oxide to the total mass of the iron salt, the copper salt, and the cerium salt is 0.2:(0.8-3), and the number of layers of the graphene oxide is less than 10.

4. The method according to claim 1, wherein 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, heating it to 75-85° C. in a water bath and soaking it for 5-15 minutes, and finally drying it in an oven at 55-65° C. for 10-14 hours for later use.

5. The method according to claim 1, wherein The calcination treatment conditions are: in a nitrogen atmosphere, in a vacuum box furnace, heating to 700-900° C. at a rate of 5-10° C. / min and calcining for 2-4 hours.

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

7. The method according to claim 1, characterized in that When the 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 / cm 2 ; Na2SO4 with a concentration of 1500~3000 mg / L is added to the reactor as an electrolyte, the reaction temperature is 25±1℃, and the reaction time is 30~180min.

8. The method according to claim 1, characterized in that The addition concentration of the modified activated carbon adsorption filler is 0.5-1.25 g / L.

9. A device for synergistic treatment of new pollutants by multi-source catalysis coupled adsorption, characterized in that: The invention comprises a reactor, wherein a partition is provided at the lower part of the reactor, an anode and a cathode are fixedly provided in the reactor and are located above the partition. The anode and the cathode are respectively connected to the positive and negative poles of a power supply located outside the reactor. A modified activated carbon adsorption filler is supported on the partition. The modified activated carbon adsorption filler is granular activated carbon modified by impregnation with a mixed solution of iron salt, copper salt, cerium salt and graphene oxide.

10. The device according to claim 9, characterized in that The reactor is provided with an aeration port, a water inlet and a water outlet from bottom to top. The aeration port is located below the partition and the water inlet and the water outlet are both located above the partition. The water inlet is connected to the water inlet pool for storing wastewater through a first external pipe and a peristaltic pump is provided between the two. The water outlet recycles the treated wastewater into the water inlet pool through a second external pipe. The aeration port is connected to the aeration pump through a third external pipe. The height of the water inlet pool is lower than the water outlet.

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