Singlet oxygen-mediated method for treating aromatic amine organic pollutants and applications thereof

Abstract

This invention belongs to the field of water pollution control and resource utilization technology, specifically relating to a method and application of singlet oxygen-mediated treatment of aromatic amine organic pollutants. The method includes the following steps: constructing a three-electrode electrochemical system using a titanium foam electrode as the working electrode; continuously introducing oxygen source gas into the electrolyte, applying voltage to the three-electrode electrochemical system to conduct an electrochemical reaction, and synthesizing singlet oxygen in situ; adding aromatic amine organic pollutants to the electrolyte, causing the aromatic amine organic pollutants to undergo an oxidative polymerization reaction under the action of singlet oxygen; and separating the solid polymerization product. Compared with existing technologies, this invention solves the problem that existing technologies struggle to achieve both efficient activation and controllable conversion when using singlet oxygen for P-AOPs. This solution achieves efficient pollutant removal through a strategy of synergistic metal activation of oxygen by highly reactive hydrogen species, while also avoiding catalyst deactivation.

Description

Technical Field

[0001] This invention belongs to the field of water pollution control and resource utilization technology, specifically relating to a method and application of treating aromatic amine organic pollutants mediated by singlet oxygen. Background Technology

[0002] Explosives are important energetic materials widely used in construction and production. The synthesis, processing, and disposal of waste explosives generate large amounts of highly concentrated and toxic aromatic organic pollutants such as trinitrotoluene (TNT) and toluene diamine (TDA), which are characterized by poor biodegradability and high environmental persistence, posing a serious challenge to ecological security and public health. While traditional advanced oxidation processes (AOPs) have been used to treat this type of wastewater, they suffer from problems such as disordered carbon emissions and high energy and chemical reagent consumption. In the context of sustainable development, polymeric advanced oxidation processes (P-AOPs) have emerged as a more suitable technology for environmental protection, requiring only a small amount of chemical reagents to convert aromatic organic pollutants into easily recyclable solid products for removal from water bodies. However, in current interface-dependent polymerization systems, polymerization products often cover active sites, leading to in-situ deposition and covering of these sites, causing catalyst deactivation and chain growth interruption. Simultaneously, solid-phase polymerization products strongly bound to the catalyst surface rely on expensive organic solvents for elution and separation, significantly increasing treatment costs and environmental burden, thus limiting the large-scale application of this technology.

[0003] Singlet oxygen ( 1 O2 has a mild oxidation potential (approximately 2.2 V vs. NHE) and a lifetime on the order of microseconds. Its free-state properties allow it to detach from the catalytic interface and diffuse over long distances in the aqueous phase. 1 O2, with its empty π* orbitals, exhibits electrophilic properties, effectively activating electron-rich aniline groups while avoiding excessive oxidation leading to ring-opening mineralization, thus possessing the potential to drive aqueous oxidative polymerization. Renewable electrical energy-driven molecular oxygen activation provides a sustainable pathway for the green synthesis of singlet oxygen. This process begins with the adsorption of O2 on the catalytic electrode surface, followed by single-electron reduction or proton-coupled electron transfer to generate various reactive oxygen intermediates. However, the strong adsorption and binding of O2 at metal sites can lead to overactivation of the OO bond, resulting in byproducts such as H2O. Previous studies have often focused on finely tuning the metal d orbital energy levels through alloying, strain modulation, and heteroatom doping to enhance the π* orbital energy of O2. * While antibonding orbital electron feedback capability exists, it is still difficult to simultaneously achieve the dual goals of efficient activation and controllable transformation. New synergistic mechanisms are urgently needed to overcome existing bottlenecks.

[0004] In existing technologies, CN117385390A discloses a method for electrochemical synthesis of singlet oxygen and its application, while CN120006326A discloses a foamed titanium-based iodine-iron dual single-atom electrode, its preparation, and its application in the preparation of singlet oxygen. However, the reaction mechanisms of CN117385390A and CN120006326A still rely on the strong adsorption and activation of O2 at iron single-atom sites, without introducing a synergistic auxiliary mechanism. As a result, O2 easily over-binds at iron sites and generates byproducts such as H2O2 and / or H2O, ultimately achieving a singlet oxygen yield of only about 60 μmol / L·min.

[0005] In addition, existing technologies, such as CN117385390A, focus on 1 CN120006326A focuses on the application of O2 in the degradation of simple organic pollutants such as tetracycline, bisphenol A, and rhodamine B in neutral wastewater and the removal of indoor volatile pollutants such as acetaldehyde. 1 While O2 is effective for removing and inactivating sulfamethoxazole, phenol, p-chlorophenol, various resistance genes, and pathogenic viruses under neutral conditions, it has not yet addressed the removal of aromatic amine pollutants from highly acidic, real-world explosive wastewater, which has a more complex aqueous matrix, higher toxicity, and is more difficult to degrade. Current treatment methods primarily rely on pollutant mineralization. During this process, organic nitrogen is easily oxidized to (nitrite) ions, and incomplete mineralization can accumulate highly toxic nitro intermediates, exacerbating environmental risks and treatment difficulties. Therefore, the treatment of aniline explosive wastewater still faces challenges such as high energy consumption and carbon emissions, loss of aromatic carbon resources, and insufficient compatibility with the concept of green development. Summary of the Invention

[0006] The purpose of this invention is to provide a method and application for treating aromatic amine organic pollutants mediated by singlet oxygen, thereby addressing the problem in existing technologies where singlet oxygen is difficult to simultaneously achieve efficient activation and controllable conversion when used with P-AOPs. This solution utilizes highly reactive hydrogen species (… * The strategy of synergistically assisting metal activation of oxygen (H) achieves efficient removal of pollutants while avoiding catalyst deactivation.

[0007] The objective of this invention is achieved through the following technical solution: The first aspect of this invention discloses a method for treating aromatic amine organic pollutants mediated by singlet oxygen, comprising the following steps: S1: A three-electrode electrochemical system is constructed using a metal foam titanium electrode as the working electrode. The active metal component in the metal foam titanium electrode is selected from one or two of cobalt and copper, and the electrolyte is an inorganic salt solution. S2: Oxygen source gas is continuously introduced into the electrolyte, and a voltage is applied to the three-electrode electrochemical system to carry out an electrochemical reaction, thereby synthesizing singlet oxygen in situ. S3: Add aromatic amine organic pollutants to the electrolyte to cause the aromatic amine organic pollutants to undergo oxidative polymerization under the action of singlet oxygen; S4: Separate solid polymer products.

[0008] Preferably, in step S1, the titanium foam electrode is prepared by the following method: A 4-10 mg / L metal salt solution containing active metal components was sprayed onto the surface of a foamed titanium substrate, dried by infrared radiation, and then transferred to a tube furnace for high-temperature annealing at 300-400 °C for 3-4 h under a mixed atmosphere of H2 / Ar. in: The metal active component is selected from copper; The thickness of the foamed titanium substrate is 0.5~2 mm.

[0009] More preferably, the active metal component is copper.

[0010] Preferably, in step S1, the electrode area of ​​the titanium foam electrode is 4~200 cm². 2 The mass percentage of the active metal component relative to the total mass of the titanium foam electrode is 0.1% to 0.5%.

[0011] Preferably, step S1 includes one or more of the following: i) The counter electrode in the three-electrode electrochemical system is an inert electrode, which includes one of a platinum sheet electrode, a ruthenium-iridium-titanium electrode, a carbon felt, and a graphite sheet; ii) The reference electrode in the three-electrode electrochemical system is selected from a silver / silver chloride electrode or a mercury / mercurous sulfate electrode; iii) The electrolyte is a 0.05~0.1 mol / L sodium sulfate solution with a pH of 1~3.

[0012] Preferably, in step S2, the oxygen source gas includes either air or oxygen, and the oxygen source gas is introduced at a rate of 50-200 mL / min.

[0013] Preferably, in step S2, the voltage is -0.6 V to -0.8 V vs. Ag / AgCl, and the reaction temperature of the electrochemical reaction is 15 to 30 °C.

[0014] Preferably, in step S3, the aromatic amine organic pollutant includes one or more of aniline, o-phenylenediamine, m-toluidine, and p-methoxyaniline.

[0015] Preferably, in step S3, the oxidative polymerization reaction takes 1 to 8 hours.

[0016] Preferably, in step S4, the separation includes sedimentation, filtration, and centrifugation.

[0017] The second aspect of this invention discloses the application of a singlet oxygen-mediated aromatic amine organic pollutant treatment method as described above in the treatment of explosive wastewater, wherein the initial concentration of aromatic amine organic pollutants in the explosive wastewater is 10~2000 mg / L.

[0018] The working principle of this invention is as follows: This scheme constructs an electrochemical system for the efficient synthesis of singlet oxygen. Utilizing the mild oxidation properties of singlet oxygen, it mediates the oxidation of aromatic pollutants to generate organic free radicals without the need for surface adsorption, thereby initiating aromatic ring coupling polymerization and generating solid products for separation and resource utilization.

[0019] In this electrochemical system, a metal single atom with weak affinity for oxygen is selected as the O2 adsorption and activation center, and it is anchored to a foamed titanium substrate with a reducing surface through strong metal-support interactions. The electron-rich oxygen vacancies adjacent to the metal active site serve as proton trapping centers, which can trigger the classical Volmer step to generate active hydrogen in situ. * H promotes the precise breaking of metal-oxygen bonds and the controlled release of key intermediates.

[0020] Compared with the prior art, the present invention has the following beneficial effects: (1) Green and environmentally friendly: The treatment method of this scheme does not require the addition of additional chemical agents. It uses oxygen / air, which is abundant and widely available in the atmosphere, as a green oxidant to synthesize singlet oxygen in situ through electrochemical processes. The reaction reagents are only water and oxygen, which have low energy consumption, no secondary pollution, and significantly lower carbon emissions than traditional advanced oxidation technologies.

[0021] (2) High efficiency and stability: Singlet oxygen can mediate polymerization without surface adsorption, avoiding the deactivation problem caused by catalyst surface dependence. The working electrode can be recycled for more than 50 hours without significant activity decay. The pollutant removal rate is 100%, and even at a low concentration of 20 mg / L, the polymerization rate can still reach more than 80%.

[0022] (3) High selectivity: The electrochemical system has high selectivity for synthesizing singlet oxygen, which can efficiently initiate the oxidative polymerization of pollutants. The polymer products have a narrow molecular weight distribution and high purity.

[0023] (4) Wide applicability: It is applicable to a variety of aromatic amine pollutants such as aniline, o-phenylenediamine, m-toluidine, and p-methoxyaniline. It is suitable for treating explosive wastewater containing such difficult-to-treat organic pollutants. Moreover, impurities in the water have no significant impact on the treatment effect, and the application scenarios are flexible.

[0024] (5) High resource value: The solid polymer products obtained after treatment can be recovered through simple sedimentation or filtration, without the need for organic solvents to extract and separate the polymer products from the catalyst surface, reducing reagent energy consumption and secondary pollution. At the same time, the obtained solid products can be further used as precursors for adsorbent materials, conductive fibers, and anti-corrosion materials, so that this treatment method can also realize the resource recovery of pollutants simultaneously, which is in line with the concept of green development.

[0025] Furthermore, compared to existing technologies (such as CN117385390A and CN120006326A), which tend to cause excessive binding of O2 at iron sites and generate byproducts such as H2O2 and / or H2O, resulting in low singlet oxygen yield, this method addresses the drawback of highly selective electrosynthesis. 1 The core of O2 adsorption lies in avoiding excessive binding of O2 at adsorption sites while ensuring a sufficient supply of interfacial hydrogen, thereby promoting the formation and desorption of *OOH species. Copper, with its milder and weaker adsorption capacity for O2, is used as the pre-activation site to pre-activate inert O2 molecules. Then, the protons from the acidic aqueous solution are rapidly reduced using the electron-rich oxygen vacancies on the surface of the titanium foam, serving as the active hydrogen source. This highly reactive active hydrogen species synergistically attack the weak Cu-O bond, simultaneously achieving rapid desorption and desorption of the key *OOH intermediate. 1 The high efficiency and selectivity of O2 generation is 3.3 times that of singlet oxygen production in CN117385390A and CN120006326A. Attached Figure Description

[0026] Figure 1 High-angle annular dark-field scanning transmission electron microscope (HAADF-STEM) image of the copper single-atom foam titanium electrode (Cu-HTF) prepared in Example 1. The bright spots marked on the image are isolated copper single atoms.

[0027] Figure 2 Energy dispersive X-ray spectral mapping (EDSmapping) image of the Cu-HTF electrode prepared in Example 1.

[0028] Figure 3 Example 2: EPR spectrum of singlet oxygen signal characterized using 2,2,6,6-tetramethylpiperidine (TEMP) as a trapping agent.

[0029] Figure 4 Example 2: Quantitative testing of singlet oxygen using furfuryl alcohol (FFA) as a molecular probe.

[0030] Figure 5 Example 3 shows the curves used to evaluate the repeatability stability of singlet oxygen electrosynthesis using FFA.

[0031] Figure 6Example 4 was verified through cyclic voltammetry testing. * The existence of H.

[0032] Figure 7 Example 4 investigated the use of tert-butanol as a quencher. * The contribution of H to singlet oxygen.

[0033] Figure 8 Example 5: Removal rate and polymerization rate of intermediate toluene diamine over time.

[0034] Figure 9 : The infrared spectrum (FT-IR) of the polymer product in Example 6.

[0035] Figure 10 Gel chromatography (GPC) chromatogram of the polymer product in Example 7.

[0036] Figure 11 Removal rate curves of different aromatic amine pollutants in Example 7.

[0037] Figure 12 Example 8: TOC removal curves before and after treatment of real explosive wastewater.

[0038] Figure 13 EPR oxygen vacancy characterization spectra of electrodes in Example 1 and Control Example 1.

[0039] Figure 14 In Example 1 and Control Example 1, singlet oxygen quantification was performed using furfuryl alcohol as a molecular probe.

[0040] Figure 15 The experiment compared the electrode in Example 1, which used tert-butanol as a quencher. * The contribution of H to singlet oxygen. Detailed Implementation

[0041] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0042] Unless otherwise specified, the reagents used in the following description are conventional commercial products, the methods used are well-known in the art, and any other matters not covered herein can be handled using existing technology.

[0043] The purpose of this invention is to provide a method for oxidatively removing organic pollutants from explosive wastewater. This method involves efficiently synthesizing singlet oxygen through electrochemical activation of molecular oxygen, which is then used to mediate the oxidative polymerization of aromatic amine organic pollutants, thereby achieving efficient pollutant removal while avoiding catalyst deactivation.

[0044] The core idea of ​​this invention is to construct an electrochemical system for the efficient synthesis of singlet oxygen. By utilizing the mild oxidation characteristics of singlet oxygen, aromatic pollutants are mediated to generate organic free radicals without the need for surface adsorption, thereby initiating aromatic ring coupling polymerization and generating solid products for separation and resource utilization.

[0045] The specific technical solution is as follows: (1) Construction of electrochemical system: A three-electrode system was adopted, with the working electrode being a metal foam titanium electrode (the active metal component is one or both of cobalt and copper, preferably copper; the thickness of the foam titanium substrate is 0.5~2 mm, and the electrode area is 4~200 cm²). 2 The active metal component in the electrode comprises 0.1% to 0.5% by mass. The counter electrode is an inert electrode such as a platinum sheet, ruthenium-iridium-titanium electrode, carbon felt, or graphite sheet. The reference electrode is a conventional reference electrode such as a silver / silver chloride electrode or a mercury / mercurous sulfate electrode. The electrolyte is an inorganic salt solution such as sodium sulfate, with a concentration of 0.05 to 0.1 mol / L and a pH controlled at 1 to 3 to ensure system stability and singlet oxygen generation efficiency.

[0046] The above-mentioned titanium foam electrode is prepared by the following method: a metal salt solution (4~10 mg / L) containing the corresponding active metal component is sprayed onto the surface of the titanium foam substrate, dried by infrared radiation, and then placed in a tube furnace for high-temperature annealing at 300~400 ℃ for 3~4 h in a mixed atmosphere of H2 / Ar.

[0047] (2) Electrochemical synthesis of singlet oxygen: Oxygen or air is continuously introduced into the electrolyte (at a rate of 50~200 mL / min), and a voltage of -0.6 V~-0.8 V vs. Ag / AgCl is applied. Electrochemical reaction is carried out at 15~30 ℃. Molecular oxygen is activated and directionally converted on the surface of the working electrode, and singlet oxygen is synthesized efficiently and selectively without interference from strong oxidizing species such as hydroxyl radicals, thus avoiding the destruction of the aromatic ring structure of pollutants.

[0048] (3) Oxidative polymerization of pollutants: Explosive wastewater is introduced into the above electrochemical system. The initial concentration of pollutants in the wastewater is 10~2000 mg / L. Singlet oxygen attacks the amino groups in the pollutant molecules, resulting in a proton-coupled electron transfer process to generate organic free radicals, which further initiate CN coupling polymerization between aromatic rings to form high molecular weight solid polymer products. The polymerization reaction time is 1~8 hours, the pollutant removal rate is ≥90%, and the yield of polymer products is ≥80%.

[0049] (4) Product separation and resource utilization: The solid-liquid separation of the polymerization products can be achieved through simple sedimentation, filtration or centrifugation. The obtained solid products can be used as adsorbent materials, conductive fibers, corrosion-resistant material precursors, etc., and the resource utilization and recycling of pollutants can be realized simultaneously, which is in line with the concept of green development.

[0050] In this scheme, the three-electrode system can use a single-chamber electrolytic cell or a flow-through electrolytic cell, and the working electrode can be recycled for more than 100 hours without significant activity decay.

[0051] In this invention, the inventors have focused on directly transferring polluting carbon from the aqueous phase to the solid phase to significantly reduce CO2 emission equivalent, promote the low-carbon resource transformation of dissolved pollutants, solve the problem of catalyst deactivation and product separation from the source, and promote the green and sustainable development of wastewater treatment.

[0052] Example 1 This embodiment provides a method for preparing a single-atom foam titanium electrode and a method for constructing an electrochemical system.

[0053] (1) Electrode preparation: A copper precursor solution with a concentration between 4 and 10 mg / L was prepared and uniformly sprayed onto the surface of the foamed titanium substrate. After infrared drying, it was placed in a tube furnace and annealed at 300-400 °C for 3-4 h in a mixed H2 / Ar atmosphere. It should be noted that the copper foamed titanium electrode prepared within the above parameter range does not significantly affect its performance in subsequent wastewater treatment. Therefore, any combination of values ​​can be taken within the given range (including the endpoints).

[0054] (2) Construction of electrochemical system: The working electrode was a foamed titanium single-atom copper electrode (area 4 cm²). 2 The electrode is 1 mm thick and contains 0.1% copper by mass. Ruthenium-iridium-titanium is used as the counter electrode, silver / silver chloride is used as the reference electrode, and the electrolyte is a 0.05 mol / L sodium sulfate solution (pH=3).

[0055] (3) Characterization and testing: The copper single-atom foam titanium electrode (Cu-HTF) prepared in Example 1 was characterized using HAADF-STEM and EDS mapping (see figures respectively). Figure 1 and Figure 2 (As shown). Copper single atoms are uniformly anchored on the surface of foamed titanium, and the isolated distribution pattern proves the successful preparation of single-atom materials.

[0056] Example 2 This embodiment provides a method for qualitative and quantitative testing and verification of electrosynthesized singlet oxygen.

[0057] (1) Experimental conditions: Oxygen was introduced into 40 mL of 0.05 mol / L sodium sulfate electrolyte (pH=3) at a flow rate of 100 mL / min, a voltage of -0.75 V vs. Ag / AgCl was applied, the reaction temperature was 25 ℃, and the reaction time was 2 hours.

[0058] (2) Qualitative analysis: The singlet oxygen signal in the system was confirmed by electron paramagnetic resonance (EPR). 2,2,6,6-Tetramethylpiperidine (TEMP) was used as a characteristic trapping agent, and its characteristic binding with singlet oxygen showed a distinct characteristic triplet signal (e.g., Figure 3 (As shown).

[0059] (3) Quantitative analysis: 100 μmol / L furfuryl alcohol (FFA) was added to the electrolyte as a singlet oxygen molecular probe. All other experimental conditions remained the same as described above. The singlet oxygen yield was calculated by detecting the remaining FFA concentration using liquid chromatography. The results are as follows: Figure 4 As shown, the singlet oxygen yield of the method of the present invention reaches about 200 μmol / L / min, which is much higher than that reported in the existing literature, and the Faraday efficiency is close to 100%, proving that the method has significant advantages in singlet oxygen synthesis efficiency and selectivity.

[0060] Example 3 This embodiment provides a test method for evaluating the stability of singlet oxygen electrosynthesis.

[0061] The electrochemical system of Example 2 was used, with 100 μmol / L FFA as the molecular probe for singlet oxygen. Each reaction cycle lasted 1 hour, followed by electrolyte replacement before the next cycle. A total of 50 cycles were tested, and the singlet oxygen yield was monitored in each cycle. Figure 5 As shown, after 50 cycles, FFA can still be completely removed within 20 minutes, and the electrode activity does not decrease significantly. The copper ion leaching was tested using inductively coupled plasma optical emission spectrometry (ICP-OES). No significant copper ion leaching was observed during the cycle, and the leaching amount gradually stabilized, proving that the working electrode prepared in Example 1 has excellent cycle stability and singlet oxygen production activity.

[0062] Example 4 This embodiment provides a test method for investigating the mechanism of singlet oxygen electrosynthesis.

[0063] Using the electrochemical system of Example 2, the presence of active hydrogen in the system was detected by cyclic voltammetry. A distinct hydrogen desorption peak was observed at around -0.2 V. Furthermore, with the introduction of oxygen, the hydrogen desorption peak rapidly weakened and even disappeared within one minute, indicating the rapid consumption of *H in the system. Figure 6 Using tert-butanol (TBA) as a quencher of active hydrogen, the study investigated the changes in the removal rate of free fuel cells (FFA). * The possible contribution of H to the singlet oxygen generation process. Results are as follows... Figure 7 As shown, after the addition of tert-butanol, the kinetic constant changed from 0.139 min... -1 Decreased to 0.022 min -1 This indicates that the oxygen reduction reactivity factor *H quenching was significantly inhibited.

[0064] Example 5 This embodiment provides a method for the oxidative polymerization of aromatic amine pollutants mediated by singlet oxygen.

[0065] Using the electrochemical system of Example 2, 20 mg / L m-toluenediamine was added to the electrolyte as a model pollutant. After the reaction, the pollutant removal rate and TOC removal rate were tested to characterize the polymerization rate. The results are as follows: Figure 8 As shown, the TDA removal rate was 100% and the polymerization rate exceeded 80%, proving that singlet oxygen also has a relatively good polymerization effect on low concentrations of aromatic amines.

[0066] Example 6 This embodiment provides a method for the separation and characterization testing of polymer products.

[0067] (1) Product separation: The solid polymer product is separated from the liquid phase by precipitation filtration. The product is repeatedly washed with deionized water and ethanol until the filtrate is clear. The product is collected and dried overnight in an oven at 60 °C.

[0068] (2) Infrared spectral analysis: The collected solid products were characterized by infrared spectroscopy, and the results are as follows: Figure 9 As shown, it was observed that the primary amine undergoes dehydrogenation to form a secondary amine in the spectrum, and the infrared peak changes from a multi-split peak of the primary amine to a broad band of the secondary amine (around 3400 cm⁻¹). -1 (At this location), the number of peaks decreases and the peak shape broadens. Furthermore, the aromatic ring extends from 1000 to 1200 cm⁻¹ within the CH plane. -1 The increased intensity and wavenumber shift indicate an increase in linear structure, revealing the polymerization from aniline to polyaniline.

[0069] (3) Gel chromatography analysis: The collected solid product was dissolved in chromatographic grade N,N-dimethylformamide (DMF), and the soluble solid product was characterized by gel chromatography. The results are as follows: Figure 10 As shown, the single symmetrical peak indicates that the sample has high purity and good separation effect. The main molecular weight of the product is concentrated at around 790 Da, and the overall molecular weight distribution is concentrated in the small molecule range, which is indeed a typical small molecule oligomer.

[0070] Example 7 This embodiment provides a universally applicable research method for the removal of different aromatic amine pollutants by singlet oxygen.

[0071] Using 20 mg / L of aromatic amine pollutants containing different substituents, such as o-phenylenediamine, m-toluidine, and p-methoxyaniline, as target pollutants, the electrochemical systems and reaction conditions of Examples 2 and 4 were used to test the removal of pollutants. The results are as follows: Figure 11As shown, the system achieved a 100% removal rate for all four pollutants and a polymerization rate of ≥70%, confirming the good universality of this method.

[0072] Example 8 This embodiment provides a real-world test method for treating explosive wastewater.

[0073] Experimental conditions: Real explosive wastewater was taken from Hongguang Chemical Plant in Yibin, Sichuan Province. Initial COD was 3607 mg / L, TN was 2944 mg / L, TOC was 2036 mg / L, conductivity was 30.4 mS / cm, pH was 1.55, and TDA concentration was 1707 mg / L. The electrochemical system of Example 2 was used, with a reaction time of 100 hours, a reaction current of 10 mA, and a tank voltage of approximately 3.78 V, while maintaining the original pH of the wastewater. After treatment, the TOC of the wastewater decreased to approximately 10 mg / L, with a removal rate exceeding 90%. Figure 12 The effluent quality meets the "Water Pollutant Discharge Standard for Ordnance Industry" (GB 14470.1-2002).

[0074] Compare with Example 1 To further illustrate the advantages and effects of the present invention, this comparative example provides a method for preparing a copper single-atom foam titanium electrode without oxygen vacancies.

[0075] (1) Electrode preparation: The specific method is basically the same as the electrode preparation method in Example 1, that is, a copper precursor solution with a concentration between 4 and 10 mg / L is prepared and uniformly sprayed onto the surface of the foamed titanium substrate. After infrared drying, it is placed in the air of an atmosphere furnace and annealed at 300-400 °C for 3-4 h to quench the oxygen vacancies that may be contained on the surface of the overall titanium electrode, and named Cu-PTF.

[0076] (2) Characterization of oxygen vacancies: The copper single-atom foam titanium electrodes prepared in Example 1 (with oxygen vacancies) and Control Example 1 (without oxygen vacancies) were characterized by EPR electron spin resonance testing. Figure 13 The significant EPR signal at g=2.001 confirms the presence of oxygen vacancies in Cu-HTF in Example 1, which contrasts sharply with the quiescent EPR signal in Cu-PTF.

[0077] (3) Quantitative testing of singlet oxygen: The experimental conditions and quantitative analysis methods were set according to Example 2. The results are as follows: Figure 14 As shown, the reaction kinetic rate constant of Cu-HTF and FFA is approximately 1.83 times that of Cu-PTF, demonstrating that the example has a significant advantage over the control example in terms of singlet oxygen synthesis efficiency and selectivity.

[0078] (4) Singlet oxygen synthesis mechanism: Referring to Example 4, tert-butanol was used as an active hydrogen quencher to investigate the possible contribution of active hydrogen to the electrosynthesis of singlet oxygen in Cu-PTF. Figure 15 As shown, the addition of tert-butanol to the electrolyte did not produce a significant change in the degradation curve, unlike Cu-HTF. Figure 7 The results show a stark contrast. Analysis reveals that, for the Cu-PTF in Control Example 1, when oxygen vacancies are lacking on the electrode material surface, * H production is significantly inhibited, thus making it difficult to exert its effects. * The synergistic effect of H in the efficient synthesis of singlet oxygen demonstrates the advanced nature of this invention and the reliability of its theory.

[0079] In summary, this method utilizes an electrochemical system for in-situ synthesis of singlet oxygen (…). 1 O2), utilizing 1 O2's mild oxidation potential and ability to react without surface adsorption mediate the selective oxidative polymerization of aromatic organic pollutants in explosives wastewater, generating rapidly separable solid polymer products, thus achieving efficient removal and resource recovery of pollutants. Compared with existing technologies, this invention eliminates the need for additional chemical oxidants, avoiding the problems of disordered carbon emissions and high energy consumption associated with traditional advanced oxidation processes (AOPs), while also solving the catalyst surface dependence deactivation problem in polymeric advanced oxidation processes (P-AOPs). This method is simple to operate, environmentally friendly, and exhibits excellent polymerization effects on aromatic pollutants containing various substituents. It demonstrates good stability and versatility in real-world explosives wastewater treatment, providing a new pathway for the green and resource-based treatment of explosives wastewater.

[0080] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A method for treating aromatic amine organic pollutants mediated by singlet oxygen, characterized in that, Includes the following steps: S1: A three-electrode electrochemical system is constructed using a metal foam titanium electrode as the working electrode. The active metal component in the metal foam titanium electrode is selected from one or two of cobalt and copper, and the electrolyte is an inorganic salt solution. S2: Oxygen source gas is continuously introduced into the electrolyte, and a voltage is applied to the three-electrode electrochemical system to carry out an electrochemical reaction, thereby synthesizing singlet oxygen in situ. S3: Add aromatic amine organic pollutants to the electrolyte to cause the aromatic amine organic pollutants to undergo oxidative polymerization under the action of singlet oxygen; S4: Separate solid polymer products.

2. The method for treating aromatic amine organic pollutants mediated by singlet oxygen according to claim 1, characterized in that, In step S1, the titanium foam electrode is prepared by the following method: A 4-10 mg / L metal salt solution containing active metal components was sprayed onto the surface of a foamed titanium substrate, dried by infrared radiation, and then transferred to a tube furnace for high-temperature annealing at 300-400 °C for 3-4 h under a mixed atmosphere of H2 / Ar. in: The metal active component is selected from copper; The thickness of the foamed titanium substrate is 0.5~2 mm.

3. The method for treating aromatic amine organic pollutants mediated by singlet oxygen according to claim 1, characterized in that, In step S1, the electrode area of ​​the titanium foam electrode is 4~200 cm². 2 The mass percentage of the active metal component relative to the total mass of the titanium foam electrode is 0.1% to 0.5%.

4. The method for treating aromatic amine organic pollutants mediated by singlet oxygen according to claim 1, characterized in that, Step S1 includes one or more of the following: i) The counter electrode in the three-electrode electrochemical system is an inert electrode, which includes one of a platinum sheet electrode, a ruthenium-iridium-titanium electrode, a carbon felt, and a graphite sheet; ii) The reference electrode in the three-electrode electrochemical system is selected from a silver / silver chloride electrode or a mercury / mercurous sulfate electrode; iii) The electrolyte is a 0.05~0.1 mol / L sodium sulfate solution with a pH of 1~3.

5. The method for treating aromatic amine organic pollutants mediated by singlet oxygen according to claim 1, characterized in that, In step S2, the oxygen source gas includes either air or oxygen, and the oxygen source gas is introduced at a rate of 50-200 mL / min.

6. The method for treating aromatic amine organic pollutants mediated by singlet oxygen according to claim 1, characterized in that, In step S2, the voltage is -0.6 V to -0.8 V vs. Ag / AgCl, and the reaction temperature of the electrochemical reaction is 15 to 30 °C.

7. The method for treating aromatic amine organic pollutants mediated by singlet oxygen according to claim 1, characterized in that, In step S3, the aromatic amine organic pollutants include one or more of aniline, o-phenylenediamine, m-toluidine, and p-methoxyaniline.

8. The method for treating aromatic amine organic pollutants mediated by singlet oxygen according to claim 1, characterized in that, In step S3, the oxidative polymerization reaction takes 1 to 8 hours.

9. The method for treating aromatic amine organic pollutants mediated by singlet oxygen according to claim 1, characterized in that, In step S4, the separation includes sedimentation, filtration, and centrifugation.

10. The application of a singlet oxygen-mediated aromatic amine organic pollutant treatment method as described in any one of claims 1 to 9 in the treatment of explosives wastewater, characterized in that, The initial concentration of aromatic amine organic pollutants in explosive wastewater is 10~2000 mg / L.

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