Electro-polymerization co-processing method for high-salt degradation-resistant organic wastewater based on penetrating electrode in-situ activation of chlorine free radicals

Abstract

The invention belongs to the field of wastewater treatment, and particularly relates to a method for co-treating high-salt degradation-resistant organic wastewater based on electro-polymerization of in-situ activated chlorine free radicals of a penetrating electrode. The method comprises the following steps: by taking a penetrating electrode as an anode, sequentially and alternately arranging the anode and the cathode to form an electrode group, placing the electrode group in a reaction tank, connecting the cathode and the anode of the electrode group with a direct-current power supply, and carrying out electrocatalytic degradation on the high-salt degradation-resistant organic wastewater to be treated in the reaction tank; the transmission type electrode comprises a porous conductive substrate and a metal oxide catalytic layer loaded on the surface of the porous conductive substrate. Under the action of low current, the metal oxide catalytic layer of the anode activates chloride ions in the wastewater in situ to generate chlorine free radicals, and refractory pollutants are degraded through the action of electrocatalytic oxidation; meanwhile, a low-current polymerization reaction is initiated to generate a polymer to adsorb pollutants, so that electrocatalytic oxidation and polymerization synchronous synergistic decontamination is realized.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment, specifically relating to a method for the synergistic treatment of high-salt, recalcitrant organic wastewater by electropolymerization based on in-situ activation of chlorine free radicals using a penetrating electrode. Background Technology

[0002] Wastewater discharged from the chemical and pharmaceutical industries contains a high proportion of recalcitrant pollutants, especially high-salt, high-chlorine wastewater with chlorine content ranging from 1000 to 10000 mg / L. This type of wastewater not only contains highly toxic pollutants with poor biodegradability, but also easily corrodes equipment. The high-salt environment further exacerbates mass transfer resistance, making it difficult for traditional technologies to balance efficiency, cost, and stability.

[0003] Currently, electrocatalytic oxidation technology is the mainstream choice for removing recalcitrant pollutants. It primarily relies on the anode to degrade organic pollutants and boasts advantages such as strong oxidation performance, high mineralization rate, environmental friendliness, and ease of operation. However, this technology suffers from low current efficiency and high energy consumption, limiting its large-scale industrial application. High-salinity wastewater can be oxidized using chlorine free radicals (Cl•, ClO•, etc.).

[0004] Electrode structure is a core factor affecting the efficiency of electrocatalysis and polymerization reactions. Traditional electrodes, due to their low mass transfer efficiency, cannot fully activate chloride ions (Cl-) in wastewater. - The generation of chlorine radicals makes it difficult for electropolymerization intermediates to fully contact and synergize with chlorine radicals; furthermore, the high viscosity of high-salt wastewater exacerbates mass transfer barriers, leading to a sharp drop in reaction efficiency. The unique structure of the through-hole electrode enhances mass transfer, reduces chloride ion corrosion of the electrode under high current, extends electrode life, and requires only low current to efficiently initiate polymerization. Simultaneously, under low current conditions, the through-hole electrode can gently activate chloride ions in wastewater to generate chlorine radicals in situ, achieving simultaneous synergistic "electrocatalytic oxidation-low current polymerization," balancing resource utilization and green low-carbon practices, thus becoming a core direction for solving industry pain points. Summary of the Invention

[0005] The purpose of this invention is to provide a method for the synergistic treatment of high-salt, recalcitrant organic wastewater by electropolymerization based on in-situ activation of chlorine radicals using a through-hole electrode. This method combines a through-hole electrode, electrocatalytic oxidation, and low-current polymerization technology, which can effectively improve current efficiency, enhance wastewater treatment effects, and reduce operating costs.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows: This invention provides a method for the electropolymerization synergistic treatment of high-salt and recalcitrant organic wastewater based on in-situ activation of chlorine radicals using a penetrating electrode. The method uses a penetrating electrode as the anode, and arranges the anode and cathode alternately to form an electrode group. The electrode group is placed in a reaction tank, and the cathode and anode of the electrode group are connected to a DC power supply. Electrocatalytic degradation of the high-salt and recalcitrant organic wastewater to be treated is carried out in the reaction tank. The penetrating electrode includes a porous conductive substrate and a metal oxide catalytic layer supported on its surface.

[0007] Furthermore, the pore diameter of the penetrating electrode is 20-60 μm. This invention addresses the problems of high mass transfer resistance and easy corrosion of traditional electrodes in high-salt, recalcitrant organic wastewater by controlling the pore diameter of the penetrating electrode to 20-60 μm. This ensures that wastewater can quickly penetrate the interior of the electrode, enhancing the contact between pollutants, chloride ions, and the electrode surface, thereby improving the activation efficiency and electrocatalytic oxidation activity of chloride ions under low current.

[0008] Furthermore, the distance between the cathode and the anode is 1-15 cm, and the distance between the two electrodes is fixed.

[0009] Furthermore, the cathode and anode power supply mode is a constant current mode, with an applied current density of 0.25-1.00 mA / cm². 2 Preferably 0.5 mA / cm 2 .

[0010] Furthermore, the porous conductive substrate is selected from one of porous titanium, graphite plate, carbon cloth, carbon felt, and carbon paper.

[0011] Furthermore, the metal oxide catalyst layer is loaded onto the surface of a porous conductive substrate using a sol-gel method or an electrochemical deposition process; the metal oxide of the metal oxide catalyst layer is selected from one of tin antimony oxide, ruthenium iridium oxide, and lead dioxide.

[0012] Furthermore, the metal oxide catalyst layer also contains a metal component, wherein the metal is selected from one or more of iron, cobalt, nickel, copper, and manganese.

[0013] Furthermore, the cathode is a metal plate or a metal mesh, and the metal material of the metal plate or metal mesh is selected from one of iron, copper, titanium, nickel, aluminum, and stainless steel; preferably, it is a stainless steel mesh.

[0014] Furthermore, the reaction tank is also equipped with an aeration device to provide oxygen for the reaction; the aeration device introduces gas during the electrocatalytic oxidation process, and the gas is selected from oxygen, air or a mixture of oxygen and air, and the aeration rate is adjusted according to the wastewater treatment requirements.

[0015] Furthermore, the high-salt, recalcitrant organic wastewater contains 500-10000 mg / L of chlorine, and the recalcitrant pollutants are selected from one or more of phenol, sulfamethoxazole, oxalic acid, and citric acid.

[0016] The beneficial effects of this invention are as follows: 1. This invention enables the in-situ activation of chloride ions (Cl-) in wastewater by the metal oxide catalyst layer at the anode under low current conditions. - The process generates chlorine radicals (Cl•, ClO•), which degrade recalcitrant pollutants through electrocatalytic oxidation; at the same time, it initiates a low-current polymerization reaction to generate polymers that adsorb pollutants, thus achieving simultaneous and synergistic removal of pollutants through electrocatalytic oxidation and polymerization. 2. The method of the present invention is low in cost, easy to operate, requires a small footprint in the reaction tank, and has a long service life; 3. This invention utilizes a penetrating electrode to enhance the diffusion and mass transfer of pollutants, resulting in good treatment effect, high current efficiency, low energy consumption, and low operation and maintenance costs. 4. This invention achieves stable low-current output through circuit design, enabling in-situ activation of chloride ions in wastewater to generate chlorine free radicals in the anode region of the penetrating electrode, while simultaneously initiating a low-current polymerization reaction, thus solving the problem of asynchronous oxidation and polymerization in traditional technologies. Attached Figure Description

[0017] Figure 1 The total organic carbon removal efficiency of different pollutants in Examples 1-6 is shown in Figure a, which is a curve of change over time, and Figure b is a bar chart of maximum removal rate. Figure 2 Different Cl values ​​in Examples 7, 8 and Comparative Example 1 - The effect of content on wastewater degradation; Figure 3 The different pore diameters in Examples 9, 10 and Comparative Example 2 are shown to have different effects on wastewater degradation. Detailed Implementation

[0018] The following examples are intended to enable those skilled in the art to more fully understand the present invention, but do not limit the invention in any way.

[0019] Unless otherwise specified, the materials used in the embodiments of the present invention can be obtained commercially or prepared according to conventional methods known to those skilled in the art.

[0020] Example 1 The anode is a through-type electrode, consisting of a porous titanium substrate and a tin-antimony oxide catalyst layer supported on its surface. The through-type electrode has a diameter of 10 cm, a thickness of 2 mm, and a pore size of 40 μm. A stainless steel mesh of the same size is used as the cathode, with a fixed distance of 1 cm between the cathode and anode plates, forming an electrode assembly. The cathode and anode of the electrode assembly are connected to the negative and positive terminals of the power supply respectively using copper wires. High-salt, recalcitrant organic wastewater passes through the anode and cathode sequentially from the inlet of the reaction tank in a direction perpendicular to the electrodes, electrocatalytically treating phenol wastewater with a concentration of 20 mg / L within the reaction tank. The added electrolyte is 100 mM sodium sulfate, containing 1000 mg / L Cl... - The wastewater influent flow rate was 15.06 mL / min. An application of 0.5 mA / cm² was performed in constant flow mode. 2 The current density and total current were 0.40 A, and the wastewater was electrocatalytically treated for 90 min.

[0021] The total organic carbon (TOC) removal rate of the treated wastewater was analyzed, and the results showed that the TOC removal rate of phenol at 20 mg / L was 56.5%. The phenol degradation rate of the treated wastewater was analyzed, and the results showed that the phenol degradation rate was 100%.

[0022] Example 2 The same method as in Example 1 was used to electrocatalytically treat sulfamethoxazole wastewater with a concentration of 20 mg / L.

[0023] The TOC removal rate of the treated wastewater was analyzed, and the results showed that the TOC removal rate of 20 mg / L sulfamethoxazole was 65.3%.

[0024] Example 3 The same method as in Example 1 was used to electrocatalytically treat sulfamethoxazole wastewater with a concentration of 40 mg / L.

[0025] TOC analysis of the treated wastewater showed that the TOC removal rate of 40 mg / L sulfamethoxazole was 46.4%.

[0026] Example 4 The oxalic acid wastewater with a concentration of 50 mg / L was electrocatalytically treated using the same method as in Example 1.

[0027] TOC analysis of the treated wastewater showed that the TOC removal rate of 50 mg / L oxalic acid was 62.8%.

[0028] Example 5 Citric acid wastewater with a concentration of 50 mg / L was electrocatalytically treated using the same method as in Example 1.

[0029] TOC analysis of the treated wastewater showed that the TOC removal rate of 50 mg / L citric acid was 29.5%.

[0030] Example 6 The same method as in Example 1 was used to electrocatalytically treat oxalic acid wastewater with a concentration of 100 mg / L.

[0031] TOC analysis of the treated wastewater showed that the TOC removal rate of 100 mg / L oxalic acid was 42.5%.

[0032] Example 7 The same method as in Example 1 was used to electrocatalytically treat phenol wastewater with a concentration of 20 mg / L, the difference being that the Cl in the wastewater... - The concentration was 500 mg / L, and other conditions remained the same as in Example 1.

[0033] The degradation rate of phenol in the treated wastewater was analyzed, and the results showed that the degradation rate of phenol was 90%.

[0034] Example 8 Using the same method as in Example 1, except that the pore size of the penetrating electrode was changed to 20 μm, and other conditions remained the same as in Example 1, phenol wastewater with a concentration of 20 mg / L was subjected to electrocatalytic treatment.

[0035] The degradation rate of phenol in the treated wastewater was analyzed, and the results showed that the degradation rate of phenol was 85%.

[0036] Example 9 Using the same method as in Example 1, except that the pore size of the penetrating electrode was changed to 60 μm, and other conditions remained the same as in Example 1, phenol wastewater with a concentration of 20 mg / L was subjected to electrocatalytic treatment.

[0037] The degradation rate of phenol in the treated wastewater was analyzed, and the results showed that the degradation rate of phenol was 85%.

[0038] Comparative Example 1 The same method as in Example 1 was used, except that Cl in the wastewater - The concentration was 0 mg / L, and other conditions were kept the same as in Example 1. Phenol wastewater with a concentration of 20 mg / L was subjected to electrocatalytic treatment.

[0039] The degradation rate of phenol in the treated wastewater was analyzed, and the results showed that the degradation rate of phenol was 75%.

[0040] Comparative Example 2 Using the same method as in Example 1, except that the pore size of the penetrating electrode was changed to 10 μm, and other conditions remained the same as in Example 1, phenol wastewater with a concentration of 20 mg / L was subjected to electrocatalytic treatment.

[0041] The degradation rate of phenol in the treated wastewater was analyzed, and the results showed that the degradation rate of phenol was 65%.

[0042] The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the implementation. The scope of protection of the present invention should be determined by the scope defined in the claims. Other variations or modifications can be made based on the above description. Obvious variations or modifications derived therefrom are still within the scope of protection of the present invention.

Claims

1. A method for the synergistic treatment of high-salt, recalcitrant organic wastewater based on in-situ activation of chlorine radicals using a penetrating electrode via electropolymerization, characterized in that... Using a penetrating electrode as the anode, an electrode group is formed by alternating anodes and cathodes. The electrode group is placed in a reaction tank, and the cathode and anode of the electrode group are connected to a DC power supply. Electrocatalytic degradation of the high-salt and recalcitrant organic wastewater to be treated is carried out in the reaction tank. The penetrating electrode includes a porous conductive substrate and a metal oxide catalytic layer supported on its surface.

2. The method for synergistic treatment of high-salt, recalcitrant organic wastewater based on in-situ activation of chlorine radicals using a penetrating electrode, as described in claim 1, is characterized in that... The diameter of the pores in the penetrating electrode is 20-60 μm.

3. The method for synergistic treatment of high-salt, recalcitrant organic wastewater based on in-situ activation of chlorine radicals using a penetrating electrode, as described in claim 1, is characterized in that... The distance between the cathode and the anode is 1-15 cm.

4. The method for synergistic treatment of high-salt, recalcitrant organic wastewater based on in-situ activation of chlorine radicals using a penetrating electrode, as described in claim 1, is characterized in that... The cathode and anode are powered in a constant current mode, with an applied current density of 0.25-1.00 mA / cm². 2 .

5. The method for synergistic treatment of high-salt, recalcitrant organic wastewater based on in-situ activation of chlorine radicals using a penetrating electrode, as described in claim 1, is characterized in that... The porous conductive substrate is selected from one of porous titanium, graphite plate, carbon cloth, carbon felt, and carbon paper.

6. The method for synergistic treatment of high-salt, recalcitrant organic wastewater based on in-situ activation of chlorine radicals using a penetrating electrode, as described in claim 1, is characterized in that... The metal oxide catalyst layer is loaded onto the surface of a porous conductive substrate by a sol-gel method or an electrochemical deposition process; the metal oxide of the metal oxide catalyst layer is selected from one of tin antimony oxide, ruthenium iridium oxide, and lead dioxide.

7. The method for synergistic treatment of high-salt, recalcitrant organic wastewater based on in-situ activation of chlorine radicals using a penetrating electrode, as described in claim 1, is characterized in that... The metal oxide catalyst layer also contains a metal component, wherein the metal is selected from one or more of iron, cobalt, nickel, copper, and manganese.

8. The method for synergistic treatment of high-salt, recalcitrant organic wastewater based on in-situ activation of chlorine radicals using a penetrating electrode, as described in claim 1, is characterized in that... The cathode is a metal plate or a metal mesh, and the metal material of the metal plate or metal mesh is selected from one of iron, copper, titanium, nickel, aluminum, and stainless steel.

9. The method for synergistic treatment of high-salt, recalcitrant organic wastewater based on in-situ activation of chlorine radicals using a penetrating electrode, as described in claim 1, is characterized in that... The reaction tank is also equipped with an aeration device to provide oxygen for the reaction.

10. The method for synergistic treatment of high-salt, recalcitrant organic wastewater based on in-situ activation of chlorine radicals using a penetrating electrode, as described in claim 1, is characterized in that... In high-salt, recalcitrant organic wastewater, the chlorine content is 500-10000 mg / L, and the recalcitrant pollutants are selected from one or more of phenol, sulfamethoxazole, oxalic acid, and citric acid.

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