Spinel-mediated non-free radical catalytic oxidation method

Abstract

The invention discloses a spinel-mediated non-free radical catalytic oxidation method which comprises the following steps: adding a spinel catalyst into organic wastewater, fully stirring to enable the spinel catalyst and organic pollutants in the organic wastewater to reach adsorption equilibrium, then adding PMS (Polymethyl Sulfonate), and reacting under the catalytic action of the spinel catalyst, thereby obtaining the spinel-mediated non-free radical catalytic oxidation. The formation and further conversion of SO5 <-> are promoted to generate < 1 > O2, so that the oxidative degradation of organic pollutants in the organic wastewater is realized; the spinel catalyst is obtained by introducing other d-orbit electron semi-full metal elements into Fe3O4, and other d-orbit electron semi-full metal elements are introduced into Fe3O4. According to the spinel-mediated non-free radical catalytic oxidation method disclosed by the invention, the spinel catalyst is only used as an electron transfer carrier and does not generate direct electron gain and loss, so that high stability is kept, and the defects of low < 1 > O2 forming efficiency, poor selectivity and easiness in instability of the catalyst in the traditional Fenton-like reaction are really overcome.

Description

Technical Field

[0001] The invention belongs to the field of sewage treatment, and in particular relates to a method for treating wastewater by utilizing Fenton reaction. Background Art

[0002] With the development of industrial civilization and the prosperity of social economy, a large amount of industrial wastewater and domestic sewage has been generated, which has serious potential harm to the ecological environment. Due to the formation of strong oxidative active species, the Fenton-like reaction based on peroxymonosulfate (PMS) has an excellent removal effect on persistent organic pollutants in wastewater. However, the components of wastewater are very complex, and free radical active substances will be quickly quenched by ions, dissolved organic matter, etc. in the wastewater, which seriously inhibits the removal efficiency of organic matter in the wastewater. In contrast, non-radical catalysis has strong anti-interference ability and is an effective strategy for treating actual wastewater.

[0003] In non-radical catalysis, compared with direct electron transfer and high-valent metal oxides, singlet oxygen ( 1 O2) has a high redox potential, anti-interference ability and green conversion pathway, and is the best oxidizing substance. A variety of heterogeneous catalysts have been developed to activate PMS generation 1 O2 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, HSO5 - Can be effectively oxidized to SO5 ·- , which transforms into 1 O2. However, non-radical catalysis mediated by carbon-based materials has disadvantages such as few active sites and weak electron delocalization, which makes it difficult to be widely used in actual wastewater treatment processes. In recent years, single-atom catalysts (SACs) have attracted widespread attention in the field of non-radical catalysis due to their abundant active sites and high atom utilization. It is reported that iron-based, cobalt-based, or copper-based SACs can achieve almost 100% selective production in Fenton-like reactions. 1 O2. The 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 the metal atomic sites can easily destroy their coordination structure, leading to ion leaching and catalyst instability. Therefore, it is urgent to develop catalysts with high stability and high 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 shortcomings and defects mentioned in the above background technology and provide a 1 A spinel-mediated non-radical catalytic oxidation method with high O2 generation efficiency, high selectivity and catalyst instability.

[0005] In order to solve the above technical problems, the technical solution proposed by the present invention is:

[0006] A spinel-mediated non-radical catalytic oxidation method comprises the following steps: adding a spinel catalyst to organic wastewater, stirring the spinel catalyst sufficiently to achieve adsorption equilibrium with organic pollutants in the organic wastewater, then adding PMS (peroxymonosulfate), and promoting SO5 ·- The formation and further transformation to generate 1 O2, to achieve oxidative degradation of organic pollutants in organic wastewater;

[0007] The spinel catalyst is obtained by introducing other d orbital electron half-filled metal elements into Fe3O4, and the tetrahedral Fe Td 2+ and octahedral Fe Oh 3+ The electron delocalization between them activates the Fe Td 2+ -O-Fe Oh 3+ Electron channels, inducing Fe Oh 3+ The PMS electrons at the site pass through Fe Td 2+ -O-Fe Oh 3+ The electron channel spontaneously transfers to Fe Td 2+ On the PMS at the site, the electrons in 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 and only acts as an electron transfer carrier.

[0008] In the above 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 O4.

[0009] In the above-mentioned spinel-mediated non-radical catalytic oxidation method, preferably, the preparation method of the spinel catalyst comprises the following steps: dissolving any one of nickel nitrate, copper nitrate or zinc nitrate and ferric nitrate in ethanol to obtain a mixed solution A, dissolving polyvinyl pyrrolidone in ethanol to obtain a mixed solution B, then adding the mixed solution B to the mixed solution A, stirring evenly to obtain a mixed solution C, and then placing the mixed solution C in an autoclave, maintaining it at 130-150°C (more preferably 140°C) for 5-7h (more preferably 6h), after the autoclave is naturally cooled to room temperature, washing the collected material with deionized water and ethanol, and freeze-drying to obtain the spinel catalyst. The above-mentioned preparation method is conducive to the preparation of the spinel catalyst of the desired structure of the present invention, and is conducive to the spinel catalyst to play the specific mechanism of action of the present invention.

[0010] In the above 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 above spinel-mediated non-radical catalytic oxidation method, preferably, after adding the spinel catalyst to the organic wastewater, stirring is continued until the oxidation degradation is completed. For example, the adsorption process and the reaction process are stirred for 2 hours, and sufficient singlet oxygen can be generated during the reaction process.

[0013] The present invention aims at treating wastewater in the traditional Fenton system 1 The low O2 generation efficiency, poor selectivity and easy catalyst instability are solved by providing a new method for enhancing non-radical wastewater treatment by regulating spinel electron delocalization. Td 2+ Introduce metal elements with high electron orbital filling degree (elements with half-filled d orbital electrons) to enhance Fe Td 2+ and octahedral Fe Oh 3+ The electrons between them are delocalized, thus activating the Fe Td 2+ -O-Fe Oh 3+ Electron channels, inducing Fe Oh 3+ The PMS electrons at the site pass through Fe Td 2+ -O-Fe Oh 3+ The electron channel spontaneously transfers to FeTd 2+ The catalyst does not directly gain or lose electrons on the PMS site, but only acts as an electron transfer carrier, maintaining high stability and accelerating SO5 ·- The formation and further transformation of non-radical species (singlet oxygen, 1 O2) generation efficiency and selectivity, and enhance the removal performance of organic pollutants in wastewater.

[0014] Taking Cu as an example, a more detailed mechanism is introduced as follows: the Cu d orbital is half-filled with electrons, and its orbital filling degree is high. There is electron repulsion between the Cu3d orbital and the O 2p orbital, and the Fe 3d and O 2p orbitals have a π-donation effect. 2+ The electron repulsion and π-donation effects can be effectively combined to further regulate Fe Td 2+ and Fe Oh 3+ The electrons between the sites are delocalized, thus activating the Fe Td 2+ -O-Fe Oh 3+ The electron channel allows the electrons in the oxidation process to pass through Fe Td 2+ -O-Fe Oh 3+ The electron transfer is carried out through the bond, avoiding the gain and loss of electrons in the catalyst itself, achieving high stability of the catalyst and Fenton-like reaction 1 Efficient generation of O2.

[0015] The present invention finds that in a Fenton-like reaction based on PMS, 1 O2 is formed by SO5 ·- The intermediate is further oxidized. ·- Compared with itself, SO4 has a high redox potential ·- and ·OH show stronger SO5 ·- Selective conversion to 1 The activity of O2. More importantly, SO4 ·- and ·OH come from the reduction of PMS, SO5 ·- If the electrons from the oxidation of PMS can be transferred to the reduction of PMS through the catalyst, the gain and loss of electrons in the catalyst itself can be avoided, maintaining the high stability of the catalyst while promoting 1The efficient generation of O2 greatly improves the prospects of Fenton-like systems in practical applications. Spinel oxide (AB2O4) is a Fenton-like catalyst required for non-radical catalysis, with a stable structure and several adjustable active sites. In general, tetrahedral A Td 2+ and octahedron B Oh 3+ The interaction with PMS is strong because their electron orbitals have many low-energy laying bands. Td 2+ and B Oh 3+ 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, and it is impossible to induce electrons from B Oh 3+ Transfer to A Td 2+ To date, the activation of spinel oxide-induced PMS still relies on the gain and loss of its own electrons, thus sacrificing its stability. Therefore, it is urgent to optimize the A Td 2+ and B Oh 3+ The degree of electron delocalization between sites is used to activate the electron transfer channel, achieving high stability of the catalyst 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, the present invention designs and invents a spinel-mediated non-radical catalytic oxidation system, which converts metal elements with high electron orbital filling degree (such as Ni 2+ , Cu 2+ 、Zn 2+ )Introduction of Fe3O4 Td 2+ In the Oh 3+ and FeTd 2+ The electron delocalization between Fe Oh 3+ The PMS electrons at the site pass through Fe Td 2+ -O-Fe Oh 3+ The bond spontaneously transfers to Fe Td 2+ Without sacrificing the stability of the catalyst, the 1 The high efficiency and selectivity of O2 generation demonstrate an effective strategy for constructing efficient and stable Fenton-like catalysts to achieve practical application goals.

[0019] The present invention can solve the limitations of the existing Fenton-like technology in treating organic wastewater, and provides a spinel-mediated non-radical catalytic oxidation system. The spinel-activated PMS designed and synthesized in the present invention overcomes the shortcoming that the activation of spinel oxide-induced PMS depends on the acquisition and loss of its own electrons, resulting in the sacrifice of its stability, and can effectively activate A Td 2+ and B Oh 3+ Electron transfer channels between sites promote 1 The efficient generation of O2 achieves high stability of the catalyst. From the perspective of thermodynamics and kinetics, SO4 with high redox potential ·- and ·OH show stronger SO5 ·- Selective conversion to 1 The activity of O2, while SO4 ·- and ·OH come from the reduction of PMS, SO5 ·- The present invention transfers the electrons in the oxidation process to the reduction process through the catalyst, thus avoiding the gain and loss of electrons in the catalyst itself. This not only achieves high stability of the catalyst, but also generates high efficiency. 1 O2, greatly improving the prospects of Fenton-like systems in practical applications.

[0020] In the present invention, our research shows that the molar ratio of the d orbital electron half-filled metal element to Fe directly affects the mechanism of action of the spinel catalyst of the present invention. After testing, a series of experiments and calculations, it is found that when the molar ratio of the two metals is 0.8:2.2, the degree of electron delocalization caused is most conducive to the activation of A Td 2+ -OB Oh 3+ The electron channel maintains the high stability of the catalyst and generates 1O2. At other ratios, the introduction of metal elements with half-filled d orbitals is not sufficient to effectively couple the electron repulsion and π contribution effects, and cannot fully increase the A content in spinel oxides. Td 2+ and B Oh 3+ The electrons between the sites are delocalized, resulting in A Td 2+ -OB Oh 3+ The electron channel is not effectively activated, sufficient electron transfer cannot be carried out, and the specific mechanism of action emphasized by the present invention cannot be exerted. The activation of spinel oxide-induced PMS still depends on the gain and loss of its own electrons, thereby sacrificing its stability.

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

[0022] The spinel-mediated non-radical catalytic oxidation method of the present invention uses a spinel catalyst with strong electron delocalization to activate PMS to generate 1 O2, during the activation process, strong electron delocalization activates Fe Td 2+ -O-Fe Oh 3+ bond electron channel, inducing Fe Oh 3+ The electrons of the PMS molecules at the site pass through Fe Td 2+ -O-Fe Oh 3+ The bond spontaneously transfers to Fe Td 2+ PMS molecules at the Fe Td 2+ and Fe Oh 3+ This synergistic behavior significantly reduces SO5 ·- The generation and further transformation energy barrier of 1 O2 is generated efficiently and selectively. At the same time, the spinel catalyst only acts as an electron transfer carrier and does not directly gain or lose electrons, thus maintaining high stability and truly overcoming the traditional Fenton-like reaction. 1 The disadvantages of O2 formation are low efficiency, poor selectivity and easy catalyst instability. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 This is the performance diagram of different catalysts in activating PMS and degrading Rhodamine B in a Fenton-like system.

[0025] Figure 2 is the corresponding k of different catalysts for the activation of PMS and degradation of Rhodamine B in a Fenton-like system obs Schematic diagram.

[0026] Figure 3 Schematic diagram of 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 OH / SO4 ·- Schematic diagram of EPR in different systems.

[0029] Figure 6 For Cu 0.8 Fe 2.2 Performance comparison chart of O4 / PMS system for removing different pollutants.

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

[0031] Figure 8 Schematic diagram of the removal of rhodamine B in a flowing Fenton-like system. DETAILED DESCRIPTION

[0032] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and meticulously below in conjunction with the accompanying drawings and preferred embodiments of the present invention, but the protection scope of the present invention is not limited to the following specific embodiments.

[0033] Unless otherwise defined, all the professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

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

[0035] The specific determination method of the content of each product in the present invention is as follows:

[0036] The concentration change of rhodamine B was measured at a wavelength of 554 nm using an ultraviolet-visible spectrophotometer. The model of the ultraviolet-visible spectrophotometer used was U-3900, Hitachi Ltd, Japan.

[0037] High pressure liquid chromatography (HPLC, LC-20A, Shimadzu, Japan) was used to quantitatively analyze the electron-withdrawing and electron-donating groups of different organic pollutants.

[0038] Example 1

[0039] The spinel catalyst of this embodiment is Cu 0.8 Fe 2.2 O4, used for the treatment of the common Rhodamine B in typical printing and dyeing wastewater.

[0040] In this example, rhodamine B, which is common in typical printing and dyeing wastewater, was used as the treatment object. First, 10 mg L -1 Measure 50 mL of Rhodamine B into a 100 mL beaker. Add 10 mg of Cu 0.8 Fe 2.2 O4, ultrasonic to make it uniformly dispersed. The suspension was stirred for 1h to ensure the establishment of adsorption equilibrium. Subsequently, 5mg PMS was added to the suspension to start the reaction. During the reaction, samples were taken with a syringe at specified intervals and immediately filtered with a 0.45μm 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 iron nitrate (Fe(NO3)3·9H2O) were completely dissolved in 20 mL of ethanol under strong stirring, and a certain amount of polyvinyl pyrrolidone (PVP) was dissolved in 20 mL of ethanol. Then, the PVP solution was added dropwise to the metal salt solution and stirred vigorously. After a period of time, the mixed solution was transferred to a 100 mL reactor. The autoclave was maintained at 140°C for 6 hours. After the autoclave was naturally cooled to room temperature, the collected material was washed with deionized water and ethanol, and freeze-dried to obtain Cu 0.8 Fe 2.2 O4.

[0043] CuFe2O4 was prepared by changing the amount of copper nitrate and ferric nitrate.

[0044] Example 2

[0045] The spinel catalyst of this embodiment is Ni 0.8 Fe 2.2 O4, used to treat the common rhodamine B in typical printing and dyeing wastewater

[0046] In this example, rhodamine B, which is common in typical printing and dyeing wastewater, was used as the treatment object. First, 10 mg L -1 Measure 50 mL of Rhodamine B into a 100 mL beaker. Add 10 mg of Ni 0.8 Fe 2.2 O4, ultrasonic to make it uniformly dispersed. The suspension was stirred for 1h to ensure the establishment of adsorption equilibrium. Subsequently, 5mg PMS was added to the suspension to start the reaction. During the reaction, samples were taken with a syringe at specified intervals and immediately filtered with a 0.45μm 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 iron nitrate (Fe(NO3)3·9H2O) were completely dissolved in 20 mL of ethanol under strong stirring, and a certain amount of polyvinyl pyrrolidone (PVP) was dissolved in 20 mL of ethanol. Then, the PVP solution was added dropwise to the metal salt solution and stirred vigorously. After a period of time, the mixed solution was transferred to a 100 mL reactor. The autoclave was maintained at 140°C for 6 hours. After the autoclave was naturally cooled to room temperature, the collected material was washed with deionized water and ethanol, and freeze-dried to obtain Ni 0.8 Fe 2.2 O4.

[0049] Example 3

[0050] The spinel catalyst of this embodiment is Zn 0.8 Fe 2.2 O4, used to treat the common rhodamine B in typical printing and dyeing wastewater

[0051] In this example, rhodamine B, which is common in typical printing and dyeing wastewater, was used as the treatment object. First, 10 mg L -1 Measure 50 mL of Rhodamine B into a 100 mL beaker. Add 10 mg Zn 0.8 Fe 2.2 O4, ultrasonic to make it uniformly dispersed. The suspension was stirred for 1h to ensure the establishment of adsorption equilibrium. Subsequently, 5mg PMS was added to the suspension to start the reaction. During the reaction, samples were taken with a syringe at specified intervals and immediately filtered with a 0.45μm 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 iron nitrate (Fe(NO3)3·9H2O) were completely dissolved in 20 mL of ethanol under strong stirring, and a certain amount of polyvinyl pyrrolidone (PVP) was dissolved in 20 mL of ethanol. Then, the PVP solution was added dropwise to the metal salt solution and stirred vigorously. After a period of time, the mixed solution was transferred to a 100 mL reactor. The autoclave was maintained at 140°C for 6 hours. After the autoclave was naturally cooled to room temperature, the collected material was washed with deionized water and ethanol, and 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 in the figure, the degradation performance of Rhodamine B in different catalytic systems was compared. In the CuFe2O4 / PMS and Fe3O4 / PMS systems, the removal efficiency of Rhodamine B was 77% and 14% within 15 minutes, respectively. obs The values ​​are 0.097min -1 and 0.011min -1 . With the electron-donating Fe in Fe3O4 Td 2+ Compared with the sites, there is no redox site in CuFe2O4, indicating that the regulation of A Td 2+ -OB Oh 3+ The electron delocalization of the bond can effectively activate the electron channel and promote the generation of oxygen reactive species (ROS). In contrast, when the molar ratio of Cu to Fe is 0.8:2.2, 0.8 Fe 2.2 In the O4 / PMS system, 100% of Rhodamine B can be removed within 15 minutes. obs (0.196min -1 ) is 2.0 times and 17.8 times higher than CuFe2O4 and Fe3O4, respectively. This result shows that the A Td 2+ -OB Oh 3+ The moderate electron delocalization of the bonds is beneficial to accelerate the electron transfer between tetrahedron and octahedron, thus further promoting the formation of ROS in the PMS-AOPs process.

[0056] Figure 3-Figure 5 Shows Cu 0.8 Fe 2.2 Active species in the O4 / PMS system. Through quenching experiments, tert-butyl alcohol was used as the quencher of ·OH, and methanol was used as the quencher of ·OH and SO4 ·- The quencher, furfuryl alcohol, 1 The quencher of O2, after the catalyst and rhodamine B reached adsorption equilibrium, first added the quencher and then added PMS for performance testing, and the preliminary judgment was 1 O2 is the main active species in the degradation process of pollutants. Electron paramagnetic resonance (EPR) was used to further detect the ROS levels in different systems. 2,2,6,6-tetramethyl-4-piperidone (TEMP)- 1 The triple signal intensity of O2 is obvious, Cu 0.8 Fe 2.2 The signal intensity of the O4 / PMS system is much higher than that of the CuFe2O4 / PMS and Fe3O4 / PMS systems. In addition, using 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as a spin trapping agent, obvious DMPO-·OH and DMPO-SO4 were observed in the Fe3O4 / PMS system. ·- These results confirm that in the PMS-based AOPs process, the Cu 2+ The introduction of Fe3O4 tetrahedral sites significantly improves 1 O2 formation efficiency and selectivity.

[0057] In the examples, Cu 0.8 Fe 2.2 The performance of the O4 / PMS system in degrading different pollutants and its long-term stability test. Figure 6 As shown, Cu 0.8 Fe 2.2 O4 / PMS has excellent degradation performance for typical electron-donating pollutants with low ionization potential, including phenol, diclofenac sodium (DCF), bisphenol A (BPA), carbamazepine (CBZ), para-chlorophenol (4-CP), para-nitrophenol (4-NP) and rhodamine B (RhB); although Cu 0.8 Fe 2.2 The degradation kinetics of the O4 / PMS system for electron-withdrawing pollutants such as dimethylformamide (DMF), benzoic acid (BA) and atrazine (ATZ) are relatively slow, but its degradation performance is much better than that of the Fe3O4 / PMS system. Figure 7-Figure 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 min, and the metal ion leaching rate was lower than the emission limit standard (1 mg L -1)) Reaction conditions: catalyst 10 mg, PMS concentration 0.5 mM, pollutant concentration 5 mg L -1 ), demonstrating the feasibility of the system in actual wastewater treatment.

[0058] After testing the Ni in Example 2 and Example 3 0.8 Fe 2.2 O4、Zn 0.8 Fe 2.2 O4 can play the role of Cu in Example 1 0.8 Fe 2.2 O4 similar performance.

[0059] It can be seen from the above examples that 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 efficient and selective production of 1 O2. Ni 2+ , Cu 2+ 、Zn 2+ enter the tetrahedral position of Fe3O4 and significantly enhance the A Td 2+ and B Oh 3+ The electron delocalization between them and A can be significantly enhanced only when the above-mentioned specific metal molar ratio is used. Td 2+ and B Oh 3+ Therefore, in the Fenton-like reaction, A Td 2 + -OB Oh 3+ The electron channel is activated and electrons are transferred from Fe Oh 3+ The PMS molecules at the site spontaneously transfer to the Fe Td 2+ The oxidation and reduction of PMS occurred simultaneously, significantly reducing the Fe Oh 3+ SO4 at site · -And Fe Oh 3+ SO5 ·- Then, the interface SO4 ·- It can quickly convert SO5 ·- Oxidation 1O2 greatly improves the 1 The efficiency and selectivity of O2 generation can achieve efficient degradation of organic pollutants, which will have great application prospects in the field of actual wastewater treatment.

Claims

1. A spinel-mediated non-radical catalytic oxidation method, It is characterized in that The method comprises the following steps: adding a spinel catalyst to the organic wastewater, stirring the spinel catalyst sufficiently to achieve adsorption equilibrium with the organic pollutants in the organic wastewater, and then adding PMS to promote SO 5 ·- The formation and further transformation to generate 1 O 2 , realize the oxidative degradation of organic pollutants in organic wastewater; The spinel catalyst is prepared by 3 O 4 By introducing other d orbital electrons half-filled metal elements, Fe Td 2+ and Fe Oh 3+ The electron delocalization between them activates the Fe Td 2+ -O-Fe Oh 3+ Electron channels, inducing Fe Oh 3+ The PMS electrons at the site pass through Fe Td 2+ -O-Fe Oh 3+ The electron channel spontaneously transfers to Fe Td 2+ On the PMS at the site, the electrons in 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 and only acts as an electron transfer carrier.

2. The spinel-mediated non-radical catalytic oxidation method according to claim 1, It is characterized in that The molar ratio of the d orbital electron half-filled metal element to Fe is 0.8:2.

2.

3. The spinel-mediated non-radical catalytic oxidation method according to claim 2, It is characterized in that 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 O 4 , Cu 0.8 Fe 2.2 O 4 or Zn 0.8 Fe 2.2 O 4 Any of .

4. The spinel-mediated non-radical catalytic oxidation method according to claim 3, It is characterized in that The preparation method of the spinel catalyst comprises the following steps: dissolving any one of nickel nitrate, copper nitrate or zinc nitrate and ferric nitrate in ethanol to obtain a mixed solution A, dissolving polyvinyl pyrrolidone in ethanol to obtain a mixed solution B, adding the mixed solution B to the mixed solution A, stirring evenly to obtain a mixed solution C, and then placing the mixed solution C in an autoclave, maintaining it at 130-150° C. for 5-7 hours, and after the autoclave is naturally cooled to room temperature, washing and collecting the material with deionized water and ethanol, and freeze-drying to obtain the spinel catalyst.

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

6. The spinel-mediated non-radical catalytic oxidation method according to any one of claims 1 to 4, It is characterized in that The amount of PMS added is such that the concentration of PMS in the reaction system is 0.2-1 mM.

7. The spinel-mediated non-radical catalytic oxidation method according to any one of claims 1 to 4, It is characterized in that After the spinel catalyst is added to the organic wastewater, stirring is continued until the oxidative degradation is completed.

Images