A method for removing refractory organic matter in wastewater by activating persulfate and simultaneously desalting

Abstract

The present application relates to wastewater treatment technical field, specifically disclose a kind of method for removing refractory organic matter in wastewater by activated persulfate and simultaneously desalination.The present application uses persulfate oxidation method to degrade organic matter in wastewater by activating two-chamber electrochemical reactor, and the salt ions generated in the degradation process are simultaneously removed.Two-chamber electrochemical reactor uses porous carbon electrode as cathode and anode, uses activated material separator and cation exchange membrane as activation and degradation unit, and is placed between two porous carbon electrodes, and separate separator is arranged between two porous carbon electrodes to form two water inlet chambers, wherein, the chamber directly contacted with activated material separator is degradation chamber, and the anode side chamber contacted with cation exchange membrane is desalination chamber, wastewater and persulfate are mixed and continuously pass through the degradation chamber and desalination chamber of the above-mentioned electrochemical reactor, and a certain voltage is applied for a certain time, so that organic matter degradation and desalination can be carried out simultaneously.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and in particular to a method for removing recalcitrant organic matter from wastewater and simultaneously desalinating it using activated persulfate. Background Technology

[0002] Persulfate oxidation has been widely used in water treatment due to its advantages of low cost, strong oxidizing power, and good removal of recalcitrant organic matter. Operationally, it typically involves directly adding persulfate to organic wastewater and activating it using a specific method to generate highly reactive oxygen species that degrade the organic matter. The process is simple and highly practical. However, this technology introduces a large amount of salt ions into the wastewater while degrading organic matter, and these salt ions remain in the water even after degradation. To improve the quality of the treated wastewater, a desalination step is necessary. Currently, common desalination technologies such as reverse osmosis and electrodialysis suffer from high energy consumption and operating costs. Furthermore, current research on persulfate oxidation technology focuses primarily on improving the removal efficiency of organic matter through specific methods, such as external field-assisted methods (light, electricity, or heat) or catalyst activation methods (metal catalysts, non-metal catalysts, etc.). There is a lack of literature research on how to remove the salts introduced during the degradation process. Therefore, researching a new method that can simultaneously remove excess salts generated during the activation and degradation of organic matter by persulfate is of great significance for reducing the cost of persulfate oxidation treatment and improving the quality of treated wastewater. Summary of the Invention

[0003] To address the issue that existing methods for degrading organic matter in wastewater using persulfate oxidation require additional desalination steps, increasing costs and energy consumption, this invention provides a method for removing recalcitrant organic matter from wastewater using activated persulfate and simultaneously desalinating it. This method primarily utilizes a combination of persulfate oxidation and membrane capacitance deionization to achieve the simultaneous removal of recalcitrant organic matter and salt from wastewater. It offers advantages such as low cost, simple operation, and wide applicability.

[0004] To solve the above-mentioned technical problems, the technical solution provided by the present invention is as follows:

[0005] A method for removing recalcitrant organic matter from wastewater and simultaneously desalinating it using activated persulfate includes the following steps:

[0006] A DC voltage is applied between the cathode and the anode;

[0007] Wastewater containing persulfate is fed into the cathode chamber of an electrochemical reactor. After degradation in the cathode chamber, it is fed into the anode chamber, where it is desalinated before being discharged.

[0008] The electrochemical reaction device includes, in sequence from cathode to anode, a cathode separation partition, an activation material partition, an anode separation partition, and an anode partition;

[0009] A first cation exchange membrane is provided between the cathode separator and the cathode separation separator; a second cation exchange membrane is provided between the activated material separator and the anode separation separator; and an anion exchange membrane is provided between the anode separation separator and the anode separator.

[0010] A cathode chamber is formed between the cathode separator and the activated material separator, and an anode chamber is formed between the second cation separator and the anode separator;

[0011] Both the cathode diaphragm and the anode diaphragm include a diaphragm frame, a separation support net disposed on the diaphragm frame, and a carbon material adsorption layer closely attached to the separation support net;

[0012] The activated material partition includes a partition frame and a porous carbon module fixed inside the partition frame.

[0013] Compared to existing technologies, the method for removing recalcitrant organic matter from wastewater and simultaneously desalinating using activated persulfate provided by this invention employs a persulfate oxidation method through a two-chamber electrochemical reaction device to activate and degrade organic matter in wastewater, while simultaneously removing salt ions generated during the degradation process. The two-chamber electrochemical reaction device uses porous carbon electrodes as anodes and cathodes, with an activation material separator and a cation exchange membrane as activation and degradation units placed between the two porous carbon electrodes. Separating separators are installed between the two porous carbon electrodes to form two inlet chambers. The chamber directly in contact with the activation material separator is the degradation chamber, and the anode-side chamber in contact with the cation exchange membrane is the desalination chamber. Wastewater and persulfate are mixed and continuously passed through the degradation and desalination chambers of the electrochemical reaction device. Applying a voltage for a certain period allows for simultaneous degradation and desalination. The wastewater treatment method provided by this invention has advantages such as simple operation, low cost, environmental friendliness, and high effluent quality, making it highly valuable for widespread application.

[0014] This invention achieves simultaneous removal of salts introduced during the persulfate oxidation of organic matter, further reducing the operational complexity and cost of wastewater treatment. The voltage applied during the simultaneous desalination process of removing organic matter is relatively low, but it can ensure the efficient removal of both salts and organic matter. It is an energy-saving, consumption-reducing, and environmentally friendly wastewater treatment method.

[0015] The technical principle of this invention is as follows: using a porous carbon electrode in the degradation chamber as the cathode and a porous carbon electrode in the desalination chamber as the anode, wastewater first enters the degradation chamber of the electrochemical reaction device. Under the condition of applying an external voltage, persulfate in the degradation chamber migrates to the activation material partition in the activation degradation unit under the action of the electric field force, and is activated in its porous carbon module to generate free radicals with strong oxidizing properties (such as sulfate free radicals, superoxide free radicals, etc.). These free radicals react with the recalcitrant organic matter adsorbed on the porous carbon material module to achieve the removal of recalcitrant organic matter. At the same time, the cations in the degraded wastewater are adsorbed onto the porous carbon electrode (cathode) after passing through the first cation exchange membrane (some of them are adsorbed onto the porous carbon material module). The wastewater from the degradation chamber flows to the desalination chamber. In the desalination chamber, the remaining anions in the wastewater are adsorbed onto the porous carbon electrode (cathode) and the porous carbon module under the action of the electric field force after passing through the anion exchange membrane, thereby achieving the simultaneous removal of organic matter and salt ions generated by the oxidation of organic matter by persulfate.

[0016] It should be noted that the recalcitrant organic matter in the wastewater described in this invention includes antibiotics, such as tetracyclines and sulfonamides; and dyes, such as methyl orange and methylene blue. Tetracycline antibiotics are preferred.

[0017] In one specific embodiment of the present invention, the persulfate is a permonosulfate containing potassium ions or a permonosulfate containing sodium ions.

[0018] In one specific embodiment of the present invention, the raw materials of the carbon material adsorption layer include: 55% to 95% carbon material, 0% to 25% conductive material, and 5% to 25% binder.

[0019] It should be noted that the electrode used in this invention is a symmetrical porous carbon-based electrode, but it can also be an asymmetrical porous carbon-based electrode.

[0020] In one specific embodiment of the present invention, the carbon material includes unsupported carbon material or carbon composite material supported on metal oxides; wherein, the unsupported carbon material includes at least one of antibiotic bacterial carbon residue, activated carbon or biochar; the carbon composite material supported on metal oxides includes carbon composite material supported on oxides of cobalt, iron, manganese or nickel.

[0021] Specifically, the antibiotic residue includes penicillin bacteria carbon residue or streptomycin bacteria carbon residue. Penicillin bacteria carbon residue is preferred.

[0022] Furthermore, the method for preparing the penicillin bacteria carbon residue includes the following steps:

[0023] After drying the penicillin bacteria fermentation residue, carbonize it at 600℃~800℃ for 1h~3h to obtain penicillin bacteria carbon residue.

[0024] In one specific embodiment of the present invention, the conductive material includes at least one of carbon black, carbon nanotubes, or graphdiene. Carbon black is preferred.

[0025] In one specific embodiment of the present invention, the adhesive comprises one or both of polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVDF). PTFE is preferred.

[0026] In one specific embodiment of the present invention, the porous carbon module includes one of activated carbon felt, graphite felt, or activated carbon cloth. It should be noted that the porous carbon module in the present invention can also be an aggregate of other forms of carbon materials.

[0027] As a specific embodiment of the present invention, the method for preparing the cathode separator and the anode separator includes the following steps:

[0028] Carbon material, conductive material and binder are mixed evenly, coated on the separation support mesh, pressed into sheets and dried to obtain cathode separator and anode separator.

[0029] In one specific embodiment of the present invention, the DC voltage is 0.8V to 1.6V, and the voltage is applied for 0.5h to 2h.

[0030] Preferably, the DC voltage is 1.2V.

[0031] Specifically, apply for 0.5 hours in the forward direction, and then apply for 0.5 hours in the reverse direction.

[0032] In one specific embodiment of the present invention, the concentration of persulfate in the wastewater is 0.08 mol / mL to 1.7 mol / mL, preferably 0.163 mol / L.

[0033] In one specific embodiment of the present invention, the inlet water flow rate of the electrochemical reaction device is 1 mL / min to 3 mL / min.

[0034] Preferably, the inlet water flow rate of the electrochemical reaction device is 2 mL / min.

[0035] In one specific embodiment of the present invention, the concentration of recalcitrant organic matter in the wastewater is 20 mg / mL to 100 mg / mL.

[0036] Preferably, the concentration of recalcitrant organic matter in the wastewater is 40 mg / mL.

[0037] In one specific embodiment of the present invention, the cathode separator, the first cation exchange membrane, the cathode separation separator, the anode separation separator, the anion exchange membrane, and the anode separator are all provided with liquid inlets and liquid outlets.

[0038] In one specific embodiment of the present invention, the cathode separation partition includes a partition frame and a separation support net disposed on the partition frame.

[0039] In one specific embodiment of the present invention, the anode separation partition includes a partition frame and a separation support net disposed on the partition frame.

[0040] In one specific embodiment of the present invention, a first fixing plate is provided on the outer side of the cathode partition; and a second fixing plate is provided on the outer side of the anode partition.

[0041] For example, the first fixing plate and the second fixing plate are acrylic plates. Both the first fixing plate and the second fixing plate are provided with liquid inlet and liquid outlet, and both adopt the bottom inlet and top outlet method.

[0042] In one specific embodiment of the present invention, a cathode current collector is provided on the cathode partition, and the cathode current collector extends beyond the cathode partition and the first fixing plate.

[0043] The anode separator is provided with an anode current collector, which extends beyond the anode separator and the second fixing plate.

[0044] Furthermore, both the cathode current collector and the anode current collector are titanium sheets, which extend beyond the fixing plate to serve as terminals for the cathode and anode.

[0045] For example, gaskets are provided between the cathode current collector and the first fixed plate, and between the anode current collector and the second fixed plate.

[0046] Furthermore, the positive and negative power terminals are connected to an external power source via wires.

[0047] Furthermore, the first fixing plate and the second fixing plate are connected by bolts.

[0048] In one specific embodiment of the present invention, the cation exchange membrane is CEM-DF-120 from Shandong Tianwei Membrane Technology Co., Ltd., and the anion exchange membrane is AEM-DF-120 from Shandong Tianwei Membrane Technology Co., Ltd.

[0049] It should be noted that the cation and anion exchange membranes must be kept moist during installation and disassembly to prevent damage. Simply moisten them with purified water. After assembling the components with bolts, secure them with screws. When installing screws, use diagonal screws and apply even force to prevent the acrylic sheet from cracking and causing leaks.

[0050] In one specific embodiment of the present invention, the electrochemical reaction device is provided in multiple ways, and the multiple electrochemical reactors are arranged in series or in parallel.

[0051] As a specific embodiment of the present invention, the electrochemical reaction device operates in either intermittent or continuous mode.

[0052] It should be noted that the method for removing recalcitrant organic matter and salt ions from wastewater provided by this invention is not affected by the water environment. Tap water, purified water, reclaimed water, or natural lake water will not have a significant impact on the degradation and desalination effect.

[0053] This invention provides a method for removing recalcitrant organic matter from wastewater using activated persulfate and simultaneously desalinizing it. Primarily targeting wastewater containing recalcitrant organic matter, the method utilizes an electric field to control the migration of persulfate, concentrating it in the activated degradation unit, thus improving the degradation efficiency and removal rate of recalcitrant organic matter. Furthermore, salt ions introduced into the solution are adsorbed through the electric field in the desalination chamber. This invention leverages the high concentration of free radicals generated by the in-situ activation of persulfate by carbon materials to achieve efficient degradation of organic matter. It also utilizes porous carbon modules with high specific surface area, high hydrophilicity, and high conductivity for electrochemical adsorption and desalination. This method boasts advantages such as high removal efficiency of organic matter and salt ions, simple operation, and low removal cost, making it highly valuable for widespread application. Attached Figure Description

[0054] Figure 1 This is a schematic diagram of an apparatus for electrochemical adsorption to remove recalcitrant organic matter from wastewater and simultaneously desalinate it, provided in an embodiment of the present invention.

[0055] Among them, 1-DC constant current and voltage power supply, 2-cathode fixing plate, 3-cathode partition, 4-first cation exchange membrane, 5-cathode separation partition, 6-activation material partition, 7-second cation exchange membrane, 8-anode separation partition, 9-anion exchange membrane, 10-anode partition, 11-anode fixing plate, 12-peristaltic pump, 13-stirrer, 14-conductivity meter, 15-ultraviolet spectrophotometer;

[0056] Figure 2 The images shown are SEM images of the penicillin bacteria carbon residue used in the embodiments of the present invention; where ac is the SEM image of the penicillin bacteria residue carbonized at 600℃, 700℃, and 800℃ for 2h, and d is the EDS image at 700℃.

[0057] Figure 3 This is a diagram showing the nitrogen adsorption-desorption and pore size distribution of the penicillin bacteria carbon slag material used in an embodiment of the present invention;

[0058] Figure 4 The XPS full spectrum and C1s peaks at different carbonization temperatures of the penicillin bacteria carbonized slag material used in the embodiments of the present invention are shown. bd represents the C1s peaks at 600℃ for 2h, 700℃ for 2h, and 800℃ for 2h, respectively. Detailed Implementation

[0059] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0060] To better illustrate the present invention, further examples are provided below.

[0061] Please see Figure 1 The electrochemical reaction apparatus used in the embodiments of the present invention will be described in detail below.

[0062] An electrochemical reaction device for removing recalcitrant organic matter from wastewater and simultaneously desalinizing it comprises, in sequence from cathode to anode, a DC constant current and voltage power supply 1, a cathode fixing plate 2, a cathode partition 3, a first cation exchange membrane 4, a cathode separation partition 5, an activation material partition 6, a second cation exchange membrane 7, an anode separation partition 8, an anion exchange membrane 9, an anode partition 10, and an anode fixing plate 11; all the above components are clamped together. A cathode chamber is formed between the cathode partition 3 and the activation material partition 6, and an anode chamber is formed between the second cation exchange membrane 7 and the anode partition 10.

[0063] In one specific embodiment of the present invention, both the cathode and anode separators are porous carbon-based electrodes, comprising a separator frame, a separation support mesh disposed on the separator frame, and a carbon material adsorption layer tightly attached to the separation support mesh. Specifically, the carbon material adsorption layer comprises: 80% penicillin bacterial residue carbon, 10% carbon black, and 10% polytetrafluoroethylene (PTFE). The preparation method of the above porous carbon electrode comprises: uniformly mixing the carbon material, carbon black, and PTFE, coating it onto the separation support mesh, pressing it into a sheet, and drying it to obtain a porous carbon-based electrode. The total mass of the carbon material adsorption layer on the porous carbon-based electrode is 0.36 g.

[0064] As a specific embodiment of the present invention, the method for preparing the penicillin bacteria fermentation residue carbon includes: drying the penicillin bacteria fermentation residue and then carbonizing it at 600-800℃ for 2 hours to obtain penicillin bacteria carbon residue. SEM and EDS images of penicillin bacteria residue carbon prepared by carbonization at different calcination temperatures for 2 hours are shown below. Figure 2 As shown in the figure, the nitrogen adsorption / desorption and pore size distribution diagram are as follows: Figure 3 As shown, the XPS full spectrum and C1s peak diagrams at different carbonization temperatures are as follows: Figure 4 As shown.

[0065] As a specific embodiment of the present invention, the activated carbon material partition frame and the activated carbon felt fixed inside the partition frame.

[0066] In one specific embodiment of the present invention, the cathode separation partition includes a partition frame and a separation support net disposed on the partition frame.

[0067] In one specific embodiment of the present invention, the cathode separator, the first cation exchange membrane, the cathode separation separator, the anode separation separator, the anion exchange membrane, and the anode separator are all provided with liquid inlets and liquid outlets.

[0068] In one specific embodiment of the present invention, the cation exchange membrane is CEM-DF-120 from Shandong Tianwei Membrane Technology Co., Ltd., and the anion exchange membrane is AEM-DF-120 from Shandong Tianwei Membrane Technology Co., Ltd.

[0069] The specific steps of using the above-mentioned device to remove recalcitrant organic matter from wastewater and simultaneously desalinate it are as follows:

[0070] After mixing persulfate and organic wastewater, the mixture is introduced into the cathode chamber through the inlet of the cathode fixing plate. A DC voltage is applied, and in the cathode chamber, persulfate ions are adsorbed onto the surface of the activated carbon felt of the activation material separator. The activated carbon felt activates the persulfate ions into highly oxidizing free radicals, which react with the organic matter adsorbed on the surface of the activated carbon felt in the solution, thereby degrading the organic matter. In the anode chamber, under the action of the electric field, potassium and sodium cations pass through the first cation exchange membrane and are adsorbed onto the porous carbon material surface of the cathode separator. Water effluent from the cathode chamber enters the anode chamber through the inlet of the anode separation separator. In the anode chamber, anions such as sulfate and bisulfate generated during the oxidation process are adsorbed onto the porous carbon material surface of the anode separator under the action of the electric field, thus achieving the simultaneous removal of organic matter and salts.

[0071] Example 1

[0072] This embodiment provides a method for treating tetracycline wastewater:

[0073] S1. Prepare penicillin bacterial residue char / carbon black / polytetrafluoroethylene electrodes as positive and negative electrodes of the electrochemical wastewater treatment unit. The positive and negative electrodes are the same. The mass fraction of penicillin bacterial residue char is 80%, carbon black is 10%, polytetrafluoroethylene is 10%, and the total mass of electrode materials is 0.36g.

[0074] S2, 50 mL of wastewater containing 0.163 mmol / L persulfate and 50 mg / L tetracycline was circulated through the electrochemical reactor at a flow rate of 2 mL / min in the storage tank. An external voltage of 1.2 V was applied, and the reaction was carried out for 1 hour (adsorption for 30 min, desorption for 30 min). After 0.5 hours of electrolysis, the removal rate of tetracycline was 77.5%, and the removal rate of salt was 66.1%.

[0075] The following control experiment was conducted using the above method:

[0076] Without DC power during the experiment, the tetracycline removal rate was only 38%. Without the addition of persulfate, the tetracycline removal rate was only 24.3%.

[0077] The above experiments demonstrate that when persulfate is introduced into the electrochemical reaction device, the activation effect of the electrode material activates the persulfate ions into highly oxidizing free radicals. Under the diffusion of free radicals and the reverse action of the electric field, the free radicals diffuse into the water, thereby achieving the degradation of organic matter. During this process, cations such as potassium and sodium in the solution and anions such as hydrogen sulfate generated in the reaction process are fixed on the surface of the porous carbon-based electrode material under the action of electroadsorption. The two have a synergistic effect, thereby achieving the simultaneous removal of organic matter and salt.

[0078] Example 2

[0079] This embodiment provides a method for treating tetracycline wastewater:

[0080] S1. Prepare penicillin bacterial residue char / carbon black / polytetrafluoroethylene electrodes as positive and negative electrodes of the electrochemical wastewater treatment unit. The positive and negative electrodes are the same. The mass fraction of penicillin bacterial residue char is 80%, carbon black is 10%, polytetrafluoroethylene is 10%, and the total mass of electrode materials is 0.36g.

[0081] S2, 50 mL of wastewater containing 0.325 mmol / L persulfate and 50 mg / L tetracycline was circulated through the electrochemical reactor at a flow rate of 2 mL / min in the storage tank. An external voltage of 1.2 V was applied for a total time of 1 h (30 min for adsorption and 30 min for desorption). After 0.5 h of electrolysis, the removal rate of tetracycline was 84.6% and the removal rate of salt was 52.8%.

[0082] Example 3

[0083] This embodiment provides a method for treating tetracycline wastewater:

[0084] S1. Prepare penicillin bacterial residue char / carbon black / polytetrafluoroethylene electrodes as positive and negative electrodes of the electrochemical wastewater treatment unit. The positive and negative electrodes are the same. The mass fraction of penicillin bacterial residue char is 80%, carbon black is 10%, polytetrafluoroethylene is 10%, and the total mass of electrode materials is 0.36g.

[0085] S2, 50 mL of wastewater containing 0.325 mmol / L persulfate and 20 mg / L tetracycline was circulated through the electrochemical reactor at a flow rate of 2 mL / min in the storage tank. An external voltage of 1.2 V was applied, and the total time for the three-stage voltage application was 1 h (30 min for adsorption and 30 min for desorption). After 0.5 h of electrolysis, the removal rate of tetracycline was 88.3%, and the salt removal rate was 52.9%.

[0086] Example 4

[0087] This embodiment provides a method for treating tetracycline wastewater:

[0088] S1. Prepare penicillin bacterial residue char / carbon black / polytetrafluoroethylene electrodes as positive and negative electrodes of the electrochemical wastewater treatment unit. The positive and negative electrodes are the same. The mass fraction of penicillin bacterial residue char is 50%, carbon black is 40%, polytetrafluoroethylene is 10%, and the total mass of electrode materials is 0.36g.

[0089] S2, 50 mL of wastewater containing 0.163 mmol / L persulfate and 50 mg / L tetracycline was circulated through the electrochemical reactor at a flow rate of 2 mL / min in the storage tank. An external voltage of 1.2 V was applied, and the total time for the three-stage voltage application was 1 h (30 min for adsorption and 30 min for desorption). After 0.5 h of electrolysis, the removal rate of tetracycline was 44%, and the salt removal rate was 32%.

[0090] Example 5

[0091] This embodiment provides a method for treating tetracycline wastewater:

[0092] S1. Prepare penicillin bacterial residue char / carbon black / polytetrafluoroethylene electrodes as positive and negative electrodes of the electrochemical wastewater treatment unit. The positive and negative electrodes are the same. The mass fraction of penicillin bacterial residue char is 80%, carbon black is 10%, polytetrafluoroethylene is 10%, and the total mass of electrode materials is 0.36g.

[0093] S2, 50 mL of wastewater containing 0.163 mmol / L persulfate and 50 mg / L tetracycline was circulated through the electrochemical reactor at a flow rate of 2 mL / min in the storage tank. An external voltage of 0.4 V was applied, and the total time for the three-stage voltage application was 2 h (60 min for adsorption and 60 min for desorption). After 1 h of electrolysis, the removal rate of tetracycline was 46%, and the salt removal rate was 30%.

[0094] Example 6

[0095] This embodiment provides a method for treating tetracycline wastewater:

[0096] S1. Prepare penicillin bacterial residue char / carbon black / polytetrafluoroethylene electrodes as positive and negative electrodes of the electrochemical wastewater treatment unit. The positive and negative electrodes are the same. The mass fraction of penicillin bacterial residue char is 80%, carbon black is 10%, polytetrafluoroethylene is 10%, and the total mass of electrode materials is 0.36g.

[0097] S2, 50 mL of wastewater containing 0.163 mmol / L persulfate and 50 mg / L tetracycline was circulated through the electrochemical reactor at a flow rate of 2 mL / min in the storage tank. An external voltage of 1.2 V was applied, and the total time for the three-stage voltage application was 1 h (30 min for adsorption and 30 min for desorption). After 0.5 h of electrolysis, the removal rate of tetracycline was 63%, and the removal rate of salt was 62%.

[0098] Example 7

[0099] This embodiment provides a method for treating tetracycline wastewater:

[0100] S1. Prepare oxytetracycline bacterial residue char / carbon black / polytetrafluoroethylene electrodes as positive and negative electrodes of the electrochemical wastewater treatment unit. The positive and negative electrodes are the same. The mass fraction of oxytetracycline bacterial residue char is 80%, carbon black is 10%, polytetrafluoroethylene is 10%, and the total mass of electrode materials is 0.36g.

[0101] S2, 50 mL of wastewater containing 0.163 mmol / L persulfate and 50 mg / L tetracycline was circulated through the electrochemical reactor at a flow rate of 2 mL / min in the storage tank. An external voltage of 1.2 V was applied, and the total time for the three-stage voltage application was 1 h (30 min for adsorption and 30 min for desorption). After 0.5 h of electrolysis, the removal rate of tetracycline was 55%, and the salt removal rate was 70%.

[0102] Example 8

[0103] This embodiment provides a method for treating tetracycline wastewater:

[0104] S1. Prepare streptomycin bacterial residue char / carbon black / polytetrafluoroethylene electrodes as positive and negative electrodes of the electrochemical wastewater treatment unit. The positive and negative electrodes are the same. The mass fraction of streptomycin bacterial residue char is 80%, carbon black is 10%, polytetrafluoroethylene is 10%, and the total mass of electrode materials is 0.36g.

[0105] S2, 50 mL of wastewater containing 0.163 mmol / L persulfate and 50 mg / L tetracycline was circulated through the electrochemical reactor at a flow rate of 1 mL / min in the storage tank. An external voltage of 1.2 V was applied, and the total time for the three-stage voltage application was 0.5 h (15 min for adsorption and 15 min for desorption). After 0.25 h of electrolysis, the removal rate of tetracycline was 51%, and the salt removal rate was 47%.

[0106] Example 9

[0107] This embodiment provides a method for treating tetracycline wastewater:

[0108] S1, Prepare activated carbon / carbon black / polytetrafluoroethylene electrodes as positive and negative electrodes of the electrochemical wastewater treatment unit. The positive and negative electrodes are the same, wherein the mass fraction of activated carbon is 80%, carbon black is 10%, polytetrafluoroethylene is 10%, and the total mass of electrode materials is 0.36g.

[0109] S2, 50 mL of wastewater containing 0.163 mmol / L persulfate and 50 mg / L tetracycline was circulated through the electrochemical reactor at a flow rate of 2 mL / min in the storage tank. An external voltage of 1.2 V was applied, and the total time for the three-stage voltage application was 1 h (30 min for adsorption and 30 min for desorption). After 0.5 h of electrolysis, the removal rate of tetracycline was 51%, and the salt removal rate was 42.4%.

[0110] Comparative Example 1

[0111] This embodiment provides a method for treating tetracycline wastewater:

[0112] S1. Prepare penicillin bacterial residue char / carbon black / polytetrafluoroethylene electrodes as positive and negative electrodes of the electrochemical wastewater treatment unit. The positive and negative electrodes are the same. The mass fraction of penicillin bacterial residue char is 80%, carbon black is 10%, polytetrafluoroethylene is 10%, and the total mass of electrode materials is 0.36g.

[0113] In S2, 50 mL of wastewater containing 0.163 mmol / L persulfate, 50 mg / L tetracycline, and 10 mmol / L p-benzoquinone was circulated through the electrochemical reactor at a flow rate of 1 mL / min in the storage tank. An external voltage of 1.2 V was applied, and the total voltage application time in three stages was 1 h (30 min for adsorption and 30 min for desorption). After 0.5 h of electrolysis, the tetracycline removal rate was 59%, and the salt removal rate was 68%. Compared with wastewater containing tetracycline without p-benzoquinone, the tetracycline removal rate decreased by 26.5%, indicating that the penicillin bacterial residue carbon electrode can activate persulfate to generate superoxide radicals, thereby degrading and removing tetracycline.

[0114] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for removing recalcitrant organic matter from wastewater and simultaneously desalinating it using activated persulfate, characterized in that, Includes the following steps: A DC voltage is applied between the cathode and the anode; Wastewater containing persulfate is fed into the cathode chamber of an electrochemical reactor. After degradation in the cathode chamber, it is fed into the anode chamber, where it is desalinated before being discharged. The electrochemical reaction device includes, in sequence from cathode to anode, a cathode separation partition, an activation material partition, an anode separation partition, and an anode partition; A first cation exchange membrane is provided between the cathode separator and the cathode separation separator; a second cation exchange membrane is provided between the activated material separator and the anode separation separator; and an anion exchange membrane is provided between the anode separation separator and the anode separator. A cathode chamber is formed between the cathode separator and the activated material separator, and an anode chamber is formed between the second cation exchange membrane and the anode separator; Both the cathode partition and the anode partition include a partition frame, a separation support net disposed on the partition frame, and a carbon material adsorption layer closely attached to the separation support net; The activated material partition includes a partition frame and a porous carbon module fixed inside the partition frame; The raw materials of the carbon material adsorption layer include: 55%~95% carbon material, 0%~25% conductive material, and 5%~25% binder; the carbon material includes unsupported carbon material or carbon composite material supported on metal oxides; wherein, the unsupported carbon material includes at least one of antibiotic bacterial carbon residue, activated carbon, or biochar; the carbon composite material supported on metal oxides includes carbon composite material supported on oxides of cobalt, iron, manganese, or nickel; the porous carbon module includes one of activated carbon felt, graphite felt, or activated carbon cloth.

2. The method for removing recalcitrant organic matter from wastewater and simultaneously desalinating using activated persulfate as described in claim 1, characterized in that, The conductive material includes at least one of carbon black, carbon nanotubes, or graphylene; and / or The adhesive includes one or both of polytetrafluoroethylene or polyvinylidene fluoride.

3. The method for removing recalcitrant organic matter from wastewater and simultaneously desalinating using activated persulfate as described in claim 1, characterized in that, The method for preparing the cathode separator and the anode separator includes the following steps: Carbon material, conductive material and binder are mixed evenly, coated on the separation support mesh, pressed into sheets and dried to obtain cathode separator and anode separator.

4. The method for removing recalcitrant organic matter from wastewater and simultaneously desalinating using activated persulfate as described in claim 1, characterized in that, The DC voltage is 0.8V~1.6V, and the voltage is applied for 0.5h~2h; and / or The concentration of persulfate in the wastewater is 0.08 mol / mL to 1.7 mol / mL.

5. The method for removing recalcitrant organic matter from wastewater and simultaneously desalinating using activated persulfate as described in claim 1, characterized in that, The cathode separator, the first cation exchange membrane, the cathode separation separator, the anode separation separator, the anion exchange membrane, and the anode separator are all provided with liquid inlets and liquid outlets.

6. The method for removing recalcitrant organic matter from wastewater and simultaneously desalinating using activated persulfate as described in claim 1, characterized in that, The cathode separation partition includes a partition frame and a separation support mesh disposed on the partition frame; The anode separation partition includes a partition frame and a separation support net disposed on the partition frame.

7. The method for removing recalcitrant organic matter from wastewater and simultaneously desalinating using activated persulfate as described in claim 1, characterized in that, A first fixing plate is provided on the outer side of the cathode partition; A second fixing plate is provided on the outer side of the anode partition.

8. The method for removing recalcitrant organic matter from wastewater and simultaneously desalinating using activated persulfate as described in claim 7, characterized in that, The cathode separator is provided with a cathode current collector, which extends beyond the cathode separator and the first fixing plate. The anode separator is provided with an anode current collector, which extends beyond the anode separator and the second fixing plate.

9. The method for removing recalcitrant organic matter from wastewater and simultaneously desalinating it using activated persulfate as described in any one of claims 1 to 8, characterized in that, The electrochemical reaction device is provided in multiple ways, and the multiple electrochemical reaction devices are arranged in series or in parallel.

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