A spinel-mediated non-radical catalytic oxidation method

Abstract

This invention discloses a spinel-mediated non-radical catalytic oxidation method, comprising the following steps: adding a spinel catalyst to organic wastewater, stirring thoroughly to achieve adsorption equilibrium between the spinel catalyst and organic pollutants in the wastewater, and then adding PMS to promote SO5 oxidation under the catalytic action of the spinel catalyst. ·‑ The formation and further transformation of [something] to generate [something]. 1 O2 is used to oxidize and degrade organic pollutants in organic wastewater. The spinel catalyst is obtained by introducing other metal elements with half-filled d-orbitals into Fe3O4. In this spinel-mediated non-radical catalytic oxidation method, the spinel catalyst acts only as an electron carrier and does not directly gain or lose electrons, maintaining high stability and truly overcoming the limitations of traditional Fenton-like reactions. 1 It suffers from the disadvantages of low O2 formation efficiency, poor selectivity, and easy catalyst instability.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment, and in particular relates to a method for treating wastewater using the Fenton reaction. Background Technology

[0002] With the development of industrial civilization and the prosperity of the social economy, a large amount of industrial wastewater and domestic sewage has been generated, posing a serious potential threat to the ecological environment. Due to the formation of highly reactive oxidizing species, persulfate (PMS)-based Fenton-like reactions have excellent removal effects on persistent organic pollutants in wastewater. However, wastewater composition is very complex, and free radical reactive substances are rapidly quenched by ions and dissolved organic matter in the wastewater, severely inhibiting the removal efficiency of organic matter. In contrast, non-radical catalysis has strong anti-interference capabilities and is an effective strategy for treating practical wastewater.

[0003] In non-radical catalysis, singlet oxygen (…) is more efficient than direct electron transfer and high-valence metal oxides. 1 O2 (O2) possesses high redox potential, strong anti-interference ability, and a green conversion pathway, making it the optimal oxidant. Various heterogeneous catalysts have been developed for activating PMS to form... 1 O2 is used to improve wastewater treatment performance. For example, carbon-based catalysts, by adjusting the conjugated structure of carbon, with the assistance of oxygen-containing functional groups, can enhance HSO5 production. - It can be effectively oxidized to SO5 ·- Thus, after self-reorganization, it transforms into 1 O2. However, carbon-based non-radical catalysis suffers from drawbacks such as a limited number of active sites and weak electron delocalization, hindering its widespread application in practical wastewater treatment processes. In recent years, single-atom catalysts (SACs) have attracted significant attention in the field of non-radical catalysis due to their abundant active sites and high atom utilization. It has been reported that iron-based, cobalt-based, or copper-based SACs can achieve almost 100% selective production in Fenton-like reactions. 1 O2. Fully exposed Fe, Co, or Cu atoms act as electron acceptors, effectively inducing the oxidation and self-recombination of PMS. However, the gain or loss of electrons at metal atom sites easily disrupts their coordination structures, leading to ion leaching and catalyst instability. Therefore, there is an urgent need to develop catalysts with high stability and high efficiency. 1 A novel Fenton-like catalyst with selective O2 generation. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies and defects mentioned in the background art above, and to provide a... 1 A spinel-mediated non-radical catalytic oxidation method with high O2 generation efficiency, high selectivity, and catalyst stability.

[0005] To solve the above-mentioned technical problems, the technical solution proposed by this invention is as follows:

[0006] A spinel-mediated non-radical catalytic oxidation method includes the following steps: adding a spinel catalyst to organic wastewater, stirring thoroughly to achieve adsorption equilibrium between the spinel catalyst and organic pollutants in the wastewater, then adding PMS (persulfate), and promoting SO5 oxidation under the catalytic action of the spinel catalyst. ·- The formation and further transformation of [something] to generate [something]. 1 O2 enables the oxidative degradation of organic pollutants in organic wastewater;

[0007] The spinel catalyst was obtained by introducing other metal elements with half-filled d-orbitals into Fe3O4. Introducing these metal elements enhances the tetrahedral Fe content. Td 2+ and octahedral Fe Oh 3+ Electron delocalization between them activates Fe in spinel. Td 2+ -O-Fe Oh 3+ Electron channels induce Fe Oh 3+ PMS electrons at the site pass through Fe Td 2+ -O-Fe Oh 3+ The electron channel spontaneously transfers to Fe Td 2+ At the site of PMS, electrons from the PMS oxidation process are transferred to the PMS reduction process through the spinel catalyst. The spinel catalyst does not directly gain or lose electrons, but only acts as an electron transport carrier.

[0008] In the above-described spinel-mediated non-radical catalytic oxidation method, preferably, the molar ratio of the d-orbital electron-half-filled metal element to Fe is 0.8:2.2. More preferably, the d-orbital electron-half-filled metal element is any one of Ni, Cu, or Zn, and the spinel catalyst is Ni. 0.8 Fe 2.2 O4, Cu 0.8 Fe 2.2 O4 or Zn 0.8 Fe 2.2 Any of the following: O4.

[0009] In the above-mentioned spinel-mediated non-radical catalytic oxidation method, preferably, the preparation method of the spinel catalyst includes the following steps: dissolving any one of nickel nitrate, copper nitrate, or zinc nitrate and ferric nitrate in ethanol to obtain mixture A; dissolving polyvinylpyrrolidone in ethanol to obtain mixture B; adding mixture B to mixture A and stirring evenly to obtain mixture C; then placing mixture C in an autoclave and maintaining it at 130-150℃ (more preferably 140℃) for 5-7 hours (more preferably 6 hours); after the autoclave naturally cools to room temperature, washing the collected material with deionized water and ethanol, and freeze-drying to obtain the spinel catalyst. The above preparation method is beneficial for preparing the spinel catalyst with the structure required by the present invention and for the spinel catalyst to exert the specific mechanism of action of the present invention.

[0010] In the above-mentioned spinel-mediated non-radical catalytic oxidation method, preferably, the concentration of organic pollutants in the organic wastewater is 10-40 mg / L. -1 .

[0011] In the above spinel-mediated non-radical catalytic oxidation method, preferably, the amount of PMS added is such that the concentration of PMS in the reaction system is 0.2-1 mM.

[0012] In the aforementioned spinel-mediated non-radical catalytic oxidation method, preferably, after adding the spinel catalyst to the organic wastewater, continuous stirring is maintained until the oxidative degradation is complete. For example, continuous stirring for 2 hours during the adsorption and reaction processes can generate sufficient singlet oxygen during the reaction.

[0013] This invention addresses the challenges of traditional Fenton-like systems in wastewater treatment processes. 1 To address the problems of low O2 generation efficiency, poor selectivity, and catalyst instability, a novel method for enhancing non-radical wastewater treatment through spinel electron delocalization modulation is proposed. This method involves directing Fe atoms into the tetrahedral sites of spinel Fe3O4. Td 2+ Introducing metallic elements with high electron orbital filling (elements with half-filled d orbitals) to enhance Fe Td 2+ and octahedral Fe Oh 3+ Electron delocalization between them, thereby activating Fe in spinel. Td 2+ -O-Fe Oh 3+ Electron channels induce Fe Oh 3+ PMS electrons at the site pass through Fe Td 2+ -O-Fe Oh 3+ The electron channel spontaneously transfers to FeTd 2+ On the PMS site, the catalyst does not directly undergo electron gain or loss, but only acts as an electron transport carrier, maintaining high stability and accelerating SO5. ·- The formation and further transformation of non-radical species (singlet oxygen, 1 The generation efficiency and selectivity of O2 enhance the removal performance of organic pollutants in wastewater.

[0014] Taking Cu as an example, a more detailed mechanism is as follows: Cu d orbitals are half-filled, exhibiting a high degree of orbital filling. Electron repulsion exists between Cu 3d orbitals and O 2p orbitals, while Fe 3d orbitals exhibit a π-donation effect with O 2p orbitals. Introducing Cu into Fe3O4... 2+ It can effectively combine the effects of electron repulsion and π-donation to further regulate Fe Td 2+ and Fe Oh 3+ Electron delocalization between sites, thereby activating Fe Td 2+ -O-Fe Oh 3+ The electron channel allows electrons to pass through Fe during the oxidation process. Td 2+ -O-Fe Oh 3+ Electron transfer occurs through bonds, avoiding electron gain and loss within the catalyst itself, thus achieving high catalyst stability and Fenton-like reaction performance. 1 Efficient generation of O2.

[0015] This invention discovers that in a PMS-based Fenton-like reaction, 1 O2 is formed by SO5 ·- It is derived from further oxidation of the intermediate. (And SO5) ·- Compared to itself, SO4 has a higher redox potential. ·- And ·OH exhibit stronger SO5 ·- Selective conversion 1 The reactivity of O2. More importantly, SO4. ·- ·OH originates from the reduction of PMS, SO5 ·- Oxidation from PMS. If electrons from the PMS oxidation process can be transferred to the PMS reduction process via a catalyst, the gain or loss of electrons within the catalyst itself can be avoided, maintaining the catalyst's high stability while promoting oxidation. 1The efficient generation of O2 greatly enhances the prospects of Fenton-like systems in practical applications. Spinel oxide (AB2O4) is a Fenton-like catalyst required for non-radical catalysis, possessing a stable structure and several tunable active sites. Generally, tetrahedral A... Td 2+ and octahedron B Oh 3+ They interact strongly with PMS because their electron orbitals have many low-energy lay-up bands. Furthermore, A... Td 2+ and B Oh 3+ These can serve as sites for PMS reduction and oxidation, respectively. However, due to the presence of A in traditional spinel oxides such as Fe3O4 and Co3O4... Td 2+ -OB Oh 3+ The electron delocalization of the bond is low, making it impossible to induce electrons from B during catalysis. Oh 3+ Transfer to A Td 2+ Site. To date, the activation of spinel oxide-induced PMS still depends on the gain and loss of its own electrons, thus sacrificing its stability. Therefore, there is an urgent need to optimize A. Td 2+ and B Oh 3+ The degree of electron delocalization between sites activates electron transport channels, achieving high catalyst stability and Fenton-like reactions. 1 Efficient generation of O2.

[0016] SO5 ·- +SO4 ·- +OH - →2SO4 2- + 1 O2+H + (1);

[0017] SO5 ·- +·OH+OH-→SO4 2- +1O2+H + (2).

[0018] Therefore, this invention designs and invents a spinel-mediated non-radical catalytic oxidation system, which utilizes metal elements with high electron orbital filling (such as Ni) 2+ Cu 2+ Zn 2+ Introducing Fe3O4 into A Td 2+ In the middle, the Fe was enhanced Oh 3+ and FeTd 2+ Electron delocalization between them induces Fe Oh 3+ PMS electrons at the site pass through Fe Td 2+ -O-Fe Oh 3+ Bond spontaneously transfers to Fe Td 2+ On the PMS site. Without sacrificing catalyst stability, it greatly improves 1 The O2 generation efficiency and selectivity demonstrate an effective strategy for constructing efficient and stable Fenton-like catalysts to achieve practical application goals.

[0019] This invention addresses the limitations of existing Fenton-like technologies for treating organic wastewater by providing a spinel-mediated non-radical catalytic oxidation system. The spinel-activated PMS designed and synthesized in this invention overcomes the drawback of spinel oxide-induced PMS activation, which relies on the gain and loss of its own electrons, leading to a sacrifice in stability. It can effectively activate A… Td 2+ and B Oh 3+ Electron transport channels between sites promote 1 The efficient generation of O2 contributes to the high stability of the catalyst. From a thermodynamic and kinetic perspective, SO4, with its high redox potential, achieves this. ·- And ·OH exhibit stronger SO5 ·- Selective conversion 1 The reactivity of O2, while SO4 ·- ·OH originates from the reduction of PMS, SO5 ·- Oxidation from PMS. This invention transfers electrons from the oxidation process to the reduction process via a catalyst, avoiding electron gain and loss within the catalyst itself. This achieves both high catalyst stability and efficient generation. 1 O2 greatly enhances the prospects of Fenton-like systems in practical applications.

[0020] In this invention, our research indicates that the molar ratio of the d-orbital electron-saturated metal element to Fe directly affects the mechanism of action of the spinel catalyst. Through testing, a series of experiments, and calculations, we found that a molar ratio of 0.8:2.2 results in the most favorable electron delocalization for activating A. Td 2+ -OB Oh 3+ The electron channels thus maintain the high stability of the catalyst and generate high efficiency. 1O2. At other ratios, the introduction of metal elements with partially filled d-orbital electrons is insufficient to effectively couple electron repulsion and π contribution, and cannot adequately increase the amount of A in spinel oxides. Td 2+ and B Oh 3+ Electron delocalization between positions, resulting in A Td 2+ -OB Oh 3+ The electron channels are not effectively activated, and sufficient electron transfer cannot be carried out. The specific mechanism of action emphasized in this invention cannot be performed. The activation of spinel oxide-induced PMS still depends on the gain and loss of its own electrons, thus sacrificing its stability.

[0021] Compared with the prior art, the advantages of the present invention are as follows:

[0022] The spinel-mediated non-radical catalytic oxidation method of the present invention utilizes a strongly electron-delocalized spinel catalyst to activate PMS to generate 1 During the activation process, O2 strongly delocalizes and activates Fe. Td 2+ -O-Fe Oh 3+ Electron channels of the bond induce Fe Oh 3+ Electrons of the PMS molecule at the site pass through Fe Td 2+ -O-Fe Oh 3+ Bond spontaneously transfers to Fe Td 2+ PMS molecules at the site, in Fe Td 2+ and Fe Oh 3+ The site enables the reduction and oxidation of PMS. This synergistic behavior significantly reduces SO5. ·- The generation and further transformation of energy barriers promote 1 O2 is generated efficiently and selectively. Meanwhile, the spinel catalyst acts solely as an electron carrier, without directly gaining or losing electrons, thus maintaining high stability and truly overcoming the limitations of traditional Fenton-like reactions. 1 It suffers from the disadvantages of low O2 formation efficiency, poor selectivity, and easy catalyst instability. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 The graph shows the performance of different catalysts in activating PMS to degrade Rhodamine B in a Fenton-like system.

[0025] Figure 2 To determine the corresponding k values ​​for different catalysts activating PMS in a Fenton-like system for the degradation of Rhodamine B. obs Schematic diagram.

[0026] Figure 3 This is a schematic diagram illustrating the selectivity of ROS generation in different systems based on quenching experiments.

[0027] Figure 4 for 1 Schematic diagram of EPR of O2 in different systems.

[0028] Figure 5 For ·OH / SO4 ·- Schematic diagrams of EPR in different systems.

[0029] Figure 6 For Cu 0.8 Fe 2.2 Performance comparison chart of different contaminants removed by the O4 / PMS system.

[0030] Figure 7 A photograph of a flowing Fenton-like system.

[0031] Figure 8 This is a schematic diagram of the removal of Rhodamine B in a flowing Fenton-like system. Detailed Implementation

[0032] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0033] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0034] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0035] The specific methods for determining the content of each product in this invention are as follows:

[0036] The concentration change of Rhodamine B was determined at a wavelength of 554 nm using a UV-Vis spectrophotometer. The UV-Vis spectrophotometer used was a U-3900, Hitachi Ltd., Japan.

[0037] Electron-withdrawing and electron-donating groups of different organic pollutants were quantitatively analyzed by high-performance liquid chromatography (HPLC, LC-20A, Shimadzu, Japan).

[0038] Example 1

[0039] In this embodiment, the spinel catalyst is Cu. 0.8 Fe 2.2 O4 is used to treat Rhodamine B, which is commonly found in typical dyeing and printing wastewater.

[0040] In this embodiment, Rhodamine B, commonly found in typical dyeing and printing wastewater, is used as the treatment target. First, 10 mg L... -1 Measure 50 mL of Rhodamine B into a 100 mL beaker. Add 10 mg of Cu to the beaker. 0.8 Fe 2.2 O4 was used to uniformly disperse the solution using ultrasound. The suspension was stirred for 1 hour to ensure adsorption equilibrium was established. Subsequently, 5 mg of PMS was added to the suspension to initiate the reaction. During the reaction, samples were taken with a syringe at specified time intervals and immediately filtered through a 0.45 μm polytetrafluoroethylene (PTFE) membrane.

[0041] The specific preparation method of the catalyst in this embodiment is as follows:

[0042] First, 0.8 mmol of copper nitrate (Cu(NO3)2·3H2O) and 2.2 mmol of ferric nitrate (Fe(NO3)3·9H2O) were completely dissolved in 20 mL of ethanol under vigorous stirring, along with a certain amount of polyvinylpyrrolidone (PVP). Then, the PVP solution was added dropwise to the metal salt solution while stirring vigorously. After a period of time, the mixture was transferred to a 100 mL autoclave. The autoclave was maintained at 140 °C for 6 h. After the autoclave cooled naturally to room temperature, the collected material was washed with deionized water and ethanol, and then freeze-dried to obtain Cu. 0.8 Fe 2.2 O4.

[0043] By changing the amounts of copper nitrate and ferric nitrate, CuFe2O4 was prepared using the same method.

[0044] Example 2

[0045] The spinel catalyst in this embodiment is Ni. 0.8 Fe 2.2 O4 is used to treat Rhodamine B, a common substance in typical dyeing and printing wastewater.

[0046] In this embodiment, Rhodamine B, commonly found in typical dyeing and printing wastewater, is used as the treatment target. First, 10 mg L... -1 Measure 50 mL of Rhodamine B into a 100 mL beaker. Add 10 mg of Ni to the beaker. 0.8 Fe 2.2 O4 was used to uniformly disperse the solution using ultrasound. The suspension was stirred for 1 hour to ensure adsorption equilibrium was established. Subsequently, 5 mg of PMS was added to the suspension to initiate the reaction. During the reaction, samples were taken with a syringe at specified time intervals and immediately filtered through a 0.45 μm polytetrafluoroethylene (PTFE) membrane.

[0047] The specific preparation method of the catalyst in this embodiment is as follows:

[0048] First, 0.8 mmol of nickel nitrate (Ni(NO3)2·3H2O) and 2.2 mmol of ferric nitrate (Fe(NO3)3·9H2O) were completely dissolved in 20 mL of ethanol under vigorous stirring, along with a certain amount of polyvinylpyrrolidone (PVP) dissolved in 20 mL of ethanol. Then, the PVP solution was added dropwise to the metal salt solution while stirring vigorously. After a period of time, the mixture was transferred to a 100 mL autoclave. The autoclave was maintained at 140 °C for 6 h. After the autoclave cooled naturally to room temperature, the collected material was washed with deionized water and ethanol, and then freeze-dried to obtain Ni. 0.8 Fe 2.2 O4.

[0049] Example 3

[0050] The spinel catalyst in this embodiment is Zn. 0.8 Fe 2.2 O4 is used to treat Rhodamine B, a common substance in typical dyeing and printing wastewater.

[0051] In this embodiment, Rhodamine B, commonly found in typical dyeing and printing wastewater, is used as the treatment target. First, 10 mg L... -1 Measure 50 mL of Rhodamine B into a 100 mL beaker. Add 10 mg of Zn to the beaker. 0.8 Fe 2.2 O4 was used to uniformly disperse the solution using ultrasound. The suspension was stirred for 1 hour to ensure adsorption equilibrium was established. Subsequently, 5 mg of PMS was added to the suspension to initiate the reaction. During the reaction, samples were taken with a syringe at specified time intervals and immediately filtered through a 0.45 μm polytetrafluoroethylene (PTFE) membrane.

[0052] The specific preparation method of the catalyst in this embodiment is as follows:

[0053] First, 0.8 mmol of zinc nitrate (Zn(NO3)3·9H2O) and 2.2 mmol of ferric nitrate (Fe(NO3)3·9H2O) were completely dissolved in 20 mL of ethanol under vigorous stirring, along with a certain amount of polyvinylpyrrolidone (PVP) dissolved in 20 mL of ethanol. Then, the PVP solution was added dropwise to the metal salt solution while stirring vigorously. After a period of time, the mixture was transferred to a 100 mL autoclave. The autoclave was maintained at 140 °C for 6 h. After the autoclave cooled naturally to room temperature, the collected material was washed with deionized water and ethanol, and then freeze-dried to obtain Zn. 0.8 Fe 2.2 O4.

[0054] The degradation effect of the present invention on Rhodamine B and its mechanism of action are discussed in detail below through the specific experimental results of Example 1.

[0055] like Figure 1 and Figure 2 As shown, the degradation performance of Rhodamine B in different catalytic systems was compared. In the CuFe2O4 / PMS and Fe3O4 / PMS systems, the removal efficiencies of Rhodamine B within 15 minutes were 77% and 14%, respectively. obs The values ​​were 0.097 min. -1 and 0.011min -1 . with electron-donating Fe in Fe3O4 Td 2+ Compared to other sites, CuFe2O4 lacks redox sites, indicating that the regulation of A Td 2+ -OB Oh 3+ Electron delocalization of bonds can effectively activate electron channels, promoting the formation of oxygen-reactive species (ROS). In contrast, when the molar ratio of Cu to Fe is 0.8:2.2, in Cu... 0.8 Fe 2.2 In the O4 / PMS system, 100% of Rhodamine B can be removed within 15 minutes. obs (0.196min -1 The concentration of A in spinel oxides was increased by 2.0 times and 17.8 times compared to CuFe₂O₄ and Fe₃O₄, respectively. This result indicates that the concentration of A in spinel oxides... Td 2+ -OB Oh 3+ Moderate electron delocalization of bonds is beneficial to accelerating electron transfer between tetrahedrons and octahedrons, thereby further promoting ROS formation during PMS-AOPs process.

[0056] Figures 3-5 Cu was shown 0.8 Fe 2.2 Active species in the O4 / PMS system. Quenching experiments were conducted, using tert-butanol as the quencher for ·OH and methanol as the quencher for ·OH and SO4. ·- quenching agent, furfuryl alcohol as 1 For the O2 quencher, after the catalyst and Rhodamine B reach adsorption equilibrium, the quencher is added first, followed by PMS for performance testing. Preliminary judgment is needed. 1 O2 is the main reactive species in the degradation process of pollutants. Electron paramagnetic resonance (EPR) was used to further detect ROS levels in different systems, including 2,2,6,6-tetramethyl-4-piperidinone (TEMP). 1 The triple signal intensity of O2 is obvious, Cu 0.8 Fe 2.2 The signal intensity of the O4 / PMS system was significantly higher than that of the CuFe2O4 / PMS and Fe3O4 / PMS systems. Furthermore, using 5,5-dimethyl-1-pyrrolline-N-oxide (DMPO) as a spin trapping agent, distinct DMPO-·OH and DMPO-SO4 groups were observed in the Fe3O4 / PMS system. ·- The characteristic peaks are higher than those of other systems. These results confirm that Cu is effective in PMS-based AOPs processes. 2+ The introduction of tetrahedral sites in Fe3O4 significantly improved 1 The formation efficiency and selectivity of O2.

[0057] Cu was measured in the examples 0.8 Fe 2.2 The performance and long-term stability of the O4 / PMS system in degrading different pollutants were investigated. For example... Figure 6 As shown, Cu 0.8 Fe 2.2 O4 / PMS exhibits excellent degradation performance for typical low-ionization-potential electron-donating pollutants, including phenol, diclofenac sodium (DCF), bisphenol A (BPA), carbamazepine (CBZ), p-chlorophenol (4-CP), p-nitrophenol (4-NP), and rhodamine B (RhB); although Cu 0.8 Fe 2.2 The O4 / PMS system exhibits relatively slow degradation kinetics for electron-withdrawing pollutants such as dimethyl (DMF), benzoic acid (BA), and atrazine (ATZ), but its degradation performance is far superior to that of the Fe3O4 / PMS system. For example... Figures 7-8 As shown, a long-term flow processing system was built, Cu 0.8 Fe 2.2 The O4 / PMS system maintained high degradation performance for up to 800 minutes, and the metal ion leaching rate was also lower than the emission limit standard (1 mg / L). -1Reaction conditions: catalyst 10 mg, PMS concentration 0.5 mM, contaminant concentration 5 mg / L -1 This demonstrates the feasibility of the system in actual wastewater treatment.

[0058] After testing, Ni in Examples 2 and 3 was found to be... 0.8 Fe 2.2 O4, Zn 0.8 Fe 2.2 O4 can function similarly to Cu in Example 1 0.8 Fe 2.2 Similar performance to O4.

[0059] As can be seen from the above embodiments, the present invention constructs a stable Cu 0.8 Fe 2.2 O4, Ni 0.8 Fe 2.2 O4, Zn 0.8 Fe 2.2 O4 catalyst for the efficient and selective production of PMS-based Fenton-like reactions. 1 O2. Ni 2+ Cu 2+ Zn 2+ It enters the tetrahedral positions of Fe3O4 and significantly enhances A. Td 2+ and B Oh 3+ Electron delocalization between them, and only under the specific metal molar ratios mentioned above, can A be significantly enhanced. Td 2+ and B Oh 3+ Electron delocalization between them. Therefore, in Fenton-like reactions, A Td 2 + -OB Oh 3+ The electron channel is activated, and electrons from Fe are released. Oh 3+ PMS molecules spontaneously transfer to Fe at the site Td 2+ PMS molecules at the site. Simultaneous oxidation and reduction of PMS significantly reduced Fe. Oh 3+ SO4 at site · -And Fe Oh 3+ SO5 at the site ·- An energy barrier is formed. Subsequently, the interface SO4 ·- It can quickly remove SO5 ·- Oxidized to 1O2, without sacrificing catalyst stability, greatly improves 1 The efficiency and selectivity of O2 generation, along with the high efficiency of organic pollutant degradation, will have great application prospects in the field of practical wastewater treatment.

Claims

1. A spinel-mediated non-radical catalytic oxidation method, characterized in that, The process includes the following steps: adding a spinel catalyst to the organic wastewater, stirring thoroughly to achieve adsorption equilibrium between the spinel catalyst and the organic pollutants in the wastewater, then adding PMS to promote the adsorption of SO5 under the catalytic action of the spinel catalyst. •- The formation and further transformation of [something] to generate [something]. 1 O2 enables the oxidative degradation of organic pollutants in organic wastewater; The spinel catalyst is obtained by introducing any one of Ni, Cu, or Zn into Fe3O4. Introducing any one of Ni, Cu, or Zn enhances the Fe... Td 2+ and Fe Oh 3+ Electron delocalization between them activates Fe in spinel. Td 2+ -O-Fe Oh 3+ Electron channels induce Fe Oh 3+ PMS electrons at the site pass through Fe Td 2+ -O-Fe Oh 3+ The electron channel spontaneously transfers to Fe Td 2+ At the site of PMS, electrons from the PMS oxidation process are transferred to the PMS reduction process through the spinel catalyst. The spinel catalyst does not directly gain or lose electrons, but only acts as an electron transport carrier. The molar ratio of any one of Ni, Cu or Zn to Fe is 0.8:2.

2.

2. The spinel-mediated non-radical catalytic oxidation method according to claim 1, characterized in that, The spinel catalyst is Ni 0.8 Fe 2.2 O4, Cu 0.8 Fe 2.2 O4 or Zn 0.8 Fe 2.2 Any of the following: O4.

3. The spinel-mediated non-radical catalytic oxidation method according to claim 2, characterized in that, The preparation method of the spinel catalyst includes the following steps: dissolving any one of nickel nitrate, copper nitrate or zinc nitrate and ferric nitrate in ethanol to obtain mixture A; dissolving polyvinylpyrrolidone in ethanol to obtain mixture B; adding mixture B to mixture A and stirring evenly to obtain mixture C; then placing mixture C in an autoclave and maintaining it at 130-150℃ for 5-7 hours; after the autoclave has naturally cooled to room temperature, washing the collected material with deionized water and ethanol, and freeze-drying to obtain the spinel catalyst.

4. The spinel-mediated non-radical catalytic oxidation method according to any one of claims 1-3, characterized in that, The concentration of organic pollutants in the organic wastewater is 10-40 mg / L. -1 .

5. The spinel-mediated non-radical catalytic oxidation method according to any one of claims 1-3, characterized in that, The amount of PMS added is such that the concentration of PMS in the reaction system is 0.2-1 mM.

6. The spinel-mediated non-radical catalytic oxidation method according to any one of claims 1-3, characterized in that, After adding spinel catalyst to the organic wastewater, stirring is carried out continuously until the oxidation and degradation are completed.

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