Preparation method of H2O2 modified Mg-MOF derivative oxide and its application in wastewater treatment

Abstract

The application relates to a preparation method of an H2O2 modified Mg-MOF derived oxide and the use of the H2O2 modified Mg-MOF derived oxide in treating wastewater, and comprises the following steps: MgNO3.6H2O and AA are dissolved in a mixed solution composed of DMF, EtOH and deionized water; the solution is heated in a reaction kettle, and the crystal is collected after cooling; the crystal is calcined at high temperature to prepare a nano metal oxide MOF-MgO; the MOF-MgO is mixed with H2O2, and is subjected to magnetic stirring under the irradiation of a xenon lamp; after washing with pure water, the mixture is collected through suction filtration and is dried to obtain a hydrogen peroxide modified Mg-MOF material; by introducing O22‑ active components on the surface of the material, a Fenton-like system is constructed to realize synergy, so that the photocatalytic oxidation of organophosphorus, the adsorption and fixation recovery of orthophosphorus and the killing of bacteria and microalgae in water are simultaneously driven, and a brand-new synergistic solution is provided for the green recovery and harmless treatment of pollutants.

Description

Technical Field

[0001] This invention relates to the field of harmless treatment of aquaculture wastewater, and in particular to a method for preparing H2O2-modified Mg-MOF-derived oxides and their use in treating wastewater. Background Technology

[0002] With the rapid development of large-scale, intensive dairy farming, the amount of wastewater generated during the farming process has increased significantly. This wastewater is typically rich in organophosphorus compounds and various pathogenic microorganisms. If discharged directly without effective treatment, it can easily lead to eutrophication of water bodies and pose potential biosafety risks, thus adversely affecting the ecological environment and human health. Existing research shows that the content of non-reactive organophosphorus compounds in dairy farm wastewater is high, typically accounting for more than 30% of the total phosphorus content. These organophosphorus compounds are highly stable in the natural environment and are difficult to remove or recover directly using conventional physical or chemical methods. Among them, adenosine triphosphate (ATP), an important organophosphorus compound widely found in animal and plant cells, is representative of polluted water bodies such as dairy farm wastewater, and its recalcitrant nature further increases the difficulty of treatment. Furthermore, given the increasing scarcity of global phosphorus resources, the ineffective recovery and utilization of these organophosphorus compounds will also result in resource waste.

[0003] For the treatment of phosphorus pollutants in aquaculture wastewater, existing technologies mostly employ chemical precipitation, biological treatment, or advanced oxidation methods. However, these methods generally suffer from complex processes, high operating costs, reliance on external energy or chemical reagents, and the potential for secondary pollution, limiting their widespread application in practical engineering. Furthermore, there is a lack of economically viable and environmentally friendly technologies for the efficient conversion and resource recovery of non-reactive organophosphorus compounds. In recent years, solar-driven photocatalytic oxidation technology has been considered a promising water treatment pathway due to its advantages of being green and energy-efficient. However, while existing peroxide-based advanced oxidation systems can effectively degrade organic pollutants, they typically rely on precious metal catalysts or stringent reaction conditions, limiting their application. On the other hand, magnesium hydroxide, as an environmentally friendly material, exhibits good adsorption properties for orthophosphorus in water, providing a basis for phosphorus recovery. However, its catalytic oxidation capacity for organophosphorus compounds under natural light conditions is weak, making it difficult to achieve efficient conversion of non-reactive organophosphorus compounds. Therefore, there is an urgent need to develop a new material and corresponding technical solution that can achieve efficient oxidation and degradation of organophosphorus compounds while also taking into account the recycling and utilization of phosphorus resources, and possess good environmental friendliness and application feasibility, so as to meet the actual needs of harmless treatment and resource utilization of aquaculture wastewater. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a method for preparing H2O2 modified Mg-MOF derivative oxide and its use in treating wastewater.

[0005] This invention is achieved through the following technical solution: A method for preparing H2O2-modified Mg-MOF-derived oxides includes the following steps: S1. Dissolve 10-15 mmol of MgNO3·6H2O and 3-5 mmol of AA in a mixed solution consisting of 50-100 mL of DMF, 2-5 mL of EtOH and 2-5 mL of deionized water. S2. After dissolving, add to a reaction vessel and heat. After cooling, collect the crystals. S3. Calcination at high temperature to produce nano-metal oxide MOF-MgO; S4. Weigh 0.1g of MOF-MgO, mix it with 2-30% H2O2, stir magnetically under light for 2-4 hours, wash with pure water, collect by vacuum filtration, and dry to obtain hydrogen peroxide modified Mg-MOF material, the surface of which is loaded with O2. 2- .

[0006] According to the above technical solution, preferably, step S2 includes: After being dissolved by ultrasonic treatment for several hours, the solution is added to a reaction vessel and heated in an oven at a temperature below 200°C for 12-48 hours. After cooling, the crystals are collected. Wash with DMF and EtOH 2-6 times respectively, and dry in a vacuum drying oven at 55-100℃ for 8-12 hours.

[0007] According to the above technical solution, preferably, in step S3, the temperature is raised to 600-650°C in a muffle furnace at a heating rate of 5°C / min, and calcined in air atmosphere for 6-10 hours to produce nano-metal oxide MOF-MgO.

[0008] According to the above technical solution, preferably, in step S4, 0.1-0.5g of MOF-MgO is weighed and mixed with H2O2 at a concentration of 2-30%, and magnetically stirred under light for 2-4 hours. After washing with pure water, the mixture is collected by vacuum filtration and dried at 50-60℃ to obtain hydrogen peroxide modified Mg-MOF material.

[0009] This application also discloses the use of H2O2 modified Mg-MOF derivative oxide for wastewater treatment. Based on the above-mentioned preparation method of H2O2 modified Mg-MOF derivative oxide, the hydrogen peroxide modified Mg-MOF material can utilize sunlight to degrade organic phosphorus and recover orthophosphorus resources, while simultaneously treating aquaculture wastewater for sterilization and algae removal.

[0010] According to the above technical solution, preferably, the hydrogen peroxide modified Mg-MOF material is prepared by surface loading of O2. 2- H2O2 is slowly released in water to construct a Fenton-like system for synergistic effects, simultaneously driving the photocatalytic oxidation of organophosphorus ATP, the adsorption, fixation and recovery of orthophosphorus, and the sterilization and algae removal in wastewater.

[0011] According to the above technical solution, preferably, the dosage of the hydrogen peroxide modified Mg-MOF material is 0.4-1 g / L, which degrades organophosphorus ATP and recovers orthophosphorus in an environment of pH=5, while simultaneously sterilizing and removing algae from aquaculture wastewater.

[0012] According to the above technical solution, preferably, the hydrogen peroxide modified Mg-MOF material degrades organophosphorus ATP in aquaculture wastewater without HA.

[0013] According to the above technical solution, preferably, the hydrogen peroxide modified Mg-MOF material can be recycled less than four times to harmlessly treat aquaculture wastewater.

[0014] The beneficial effects of this invention are: First, the hydrogen peroxide-modified Mg-MOF material prepared in this invention has a unique porous layered structure and a large specific surface area. At the same time, abundant oxygen defect sites and a high content of active oxygen species are introduced during the calcination and modification process, which significantly improves the material's reactivity and catalytic performance, providing a good structural basis for the efficient conversion of organophosphorus compounds.

[0015] Secondly, the hydrogen peroxide-modified Mg-MOF material prepared in this invention utilizes surface-loaded O2... 2- By slowly releasing hydrogen peroxide in an aquatic environment, a Fenton-like reaction system is constructed. Simultaneously, under sunlight, the material can be excited to generate various oxidizing active substances, forming a synergistic mechanism of "Fenton-like oxidation + photocatalytic oxidation." The coupling of these two pathways enables highly efficient degradation of non-reactive organophosphorus compounds, significantly improving degradation efficiency and reducing dependence on external energy and chemical reagents compared to a single oxidation pathway.

[0016] Furthermore, the material provided by this invention, while degrading organophosphorus compounds, can also fix and recover the generated orthophosphate through the adsorption of Mg-based materials, achieving an integrated treatment effect of pollutant removal and resource utilization. This effectively avoids phosphorus resource loss and has good resource recycling value. Simultaneously, in the process of treating aquaculture wastewater, the material provided by this invention not only removes organophosphorus compounds but also significantly inhibits or kills bacteria and algae in the water, achieving synergistic treatment functions of phosphorus removal, sterilization, and algae removal. This effectively reduces the risk of eutrophication and biosafety hazards, improving the overall effect of wastewater treatment. Attached Figure Description

[0017] Figure 1 These are Fourier transform infrared (FTIR) images of the three materials Mg(OH)2-HP-1 / 2 / 3 in this invention.

[0018] Figure 2 This is a schematic diagram illustrating the catalytic oxidation removal capabilities of the three materials Mg(OH)2-HP-1 / 2 / 3 in this invention for adenosine triphosphate.

[0019] Figure 3 This is a schematic diagram of the kinetic fitting of the three materials Mg(OH)2-HP-1 / 2 / 3 in this invention.

[0020] Figure 4 This is the full X-ray photoelectron spectroscopy (XPS) spectrum of Mg(OH)2-HP and MOF-Mg(OH)2-HP in this invention.

[0021] Figure 5 This is the X-ray photoelectron spectroscopy (XPS) Mg 2p spectrum of Mg(OH)2-HP and MOF-Mg(OH)2-HP in this invention.

[0022] Figure 6 This is the X-ray photoelectron spectroscopy (XPS) O 1s spectrum of Mg(OH)2-HP and MOF-Mg(OH)2-HP in this invention.

[0023] Figure 7 This is the electron spin resonance (EPR) fitting spectrum of Mg(OH)2-HP and MOF-Mg(OH)2-HP in this invention.

[0024] Figure 8In the diagram, (a) is a schematic diagram of the catalytic oxidation capacity of Mg(OH)2-HP and MOF-Mg(OH)2-HP under sunlight and shading conditions; (b) is a schematic diagram of the kinetic fitting of the catalytic oxidation capacity of Mg(OH)2-HP and MOF-Mg(OH)2-HP under sunlight and shading conditions; (c) is a graph showing the effect of dosage on the catalytic oxidation capacity of MOF-Mg(OH)2-HP to remove pollutants; (d) is a schematic diagram of the kinetic fitting of dosage on the catalytic oxidation capacity of MOF-Mg(OH)2-HP to remove pollutants; (e) is a graph showing the effect of solution pH on the catalytic oxidation capacity of MOF-Mg(OH)2-HP to remove pollutants; and (f) is a graph showing the effect of solution pH on the catalytic oxidation capacity of MOF-Mg(OH)2-HP to remove pollutants. (g) Schematic diagram of kinetic fitting of the value on the ability of MOF-Mg(OH)2-HP to catalytically oxidize and remove pollutants; (h) Schematic diagram of the effect of coexisting ions on the ability of MOF-Mg(OH)2-HP to catalytically oxidize and remove pollutants; (i) Schematic diagram of the recycling capacity of MOF-Mg(OH)2-HP; (j) Schematic diagram of the bactericidal effect of MOF-Mg(OH)2-HP on aquaculture wastewater; (k) Schematic diagram of the bactericidal effect of MOF-Mg(OH)2-HP on fishpond water; (l) Schematic diagram of the bactericidal effect of MOF-Mg(OH)2-HP on Chlorella proteoglycans.

[0025] Figure 9 This is a schematic diagram illustrating the oxidative removal capacity of MOF-Mg(OH)2-HP for β-glycerophosphate (β-GA) and phytic acid (IP6) and other organophosphates in this invention.

[0026] Figure 10 These are scanning electron microscope images of ATP catalytic oxidation and orthophosphate recovery using MOF-Mg(OH)2-HP in this invention, and a comparison of elemental scan images before and after use.

[0027] Figure 11 This is a comparison of Fourier transform infrared spectra before and after the oxidation of ATP and recovery of orthophosphate by MOF-Mg(OH)2-HP in this invention.

[0028] Figure 12 This is a comparison of the O 1s X-ray photoelectron spectra before and after the MOF-Mg(OH)2-H reaction in this invention.

[0029] Figure 13 This is a comparison of Mg 2p X-ray photoelectron spectra before and after the MOF-Mg(OH)2-H reaction in this invention.

[0030] Figure 14 This is a comparison diagram of electron paramagnetic resonance signals before and after the MOF-Mg(OH)2-H reaction in this invention.

[0031] Figure 15 This is an experimental diagram of the quenching of active substances in Mg(OH)2-HP and MOF-Mg(OH)2-HP in this invention.

[0032] Figure 16 This is an experimental diagram of the present invention using the same volume and concentration of MeOH, EDTA-2Na, L-His, and BQ to quench ·OH.

[0033] Figure 17 This invention uses the same volume and concentration of MeOH, EDTA-2Na, L-His, and BQ to quench h. + The experimental diagram.

[0034] Figure 18 This invention uses the same volume and concentration of MeOH, EDTA-2Na, L-His, and BQ for quenching. 1 Experimental diagram of O2.

[0035] Figure 19 This invention uses the same volume and concentration of MeOH, EDTA-2Na, L-His, and BQ quenching·O2. - The experimental diagram.

[0036] Figure 20 This is a schematic diagram of the UV-Vis diffuse reflectance detection of Mg(OH)2-HP and MOF-Mg(OH)2-HP in this invention.

[0037] Figure 21 This is a graph showing the data processing and analysis of Mg(OH)2-HP and MOF-Mg(OH)2-HP ultraviolet-visible (UV-Vis) diffuse reflectance detection in this invention.

[0038] Figure 22 This is a schematic diagram of the X-ray photoelectron spectroscopy derived valence band spectra of Mg(OH)2-HP and MOF-Mg(OH)2-HP in this invention.

[0039] Figure 23 This is an analysis diagram of the instantaneous photocurrent response of Mg(OH)2-HP and MOF-Mg(OH)2-HP in this invention.

[0040] Figure 24 This is a schematic diagram of the electrochemical impedance spectroscopy of Mg(OH)2-HP and MOF-Mg(OH)2-HP in this invention.

[0041] Figure 25 This is a schematic diagram of the linear sweep voltammetry test of Mg(OH)2-HP and MOF-Mg(OH)2-HP in this invention. Detailed Implementation

[0042] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and preferred embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0043] Example 1: This invention provides a method for preparing H2O2-modified Mg-MOF-derived oxides, comprising the following steps: S1. Dissolve 10 mmol of MgNO3·6H2O and 3 mmol of adipic acid (AA) in a mixed solution consisting of 60 mL of N,N-dimethylformamide (DMF), 4 mL of anhydrous ethanol (EtOH) and 4 mL of deionized water. S2. After being dissolved by ultrasonic treatment for 2 hours, the solution was added to a 100 mL polytetrafluoroethylene-lined high-pressure reactor and heated at 120 °C for 24 hours in an oven. After cooling, the crystals were collected, washed twice with DMF and EtOH respectively, and dried in a vacuum drying oven at 80 °C for 8 hours. S3. Calcination at high temperature to prepare nano-metal oxide MOF-MgO; The temperature is raised to 600℃ in a muffle furnace at a heating rate of 5℃ / min and calcined in air atmosphere for 8h to prepare nano-metal oxide MOF-MgO. S4. Weigh 0.1 g of MOF-MgO and mix it with H2O2 at concentrations of 30%, 20%, and 10%, respectively. Stir magnetically for 2 h under xenon lamp irradiation, wash three times with pure water, filter and collect, and dry at 55 °C overnight to obtain hydrogen peroxide modified Mg-MOF material, whose surface is loaded with O2. 2- .

[0044] Materials mixed with H2O2 at concentrations of 30%, 20%, and 10% were named MOF-Mg(OH)2-HP-1 / 2 / 3, where HP stands for Hydrogen peroxide modification. A control material prepared using commercially available MgO instead of MOF-MgO was named Mg(OH)2-HP.

[0045] Fourier transform infrared (FTIR) spectra of the three materials Mg(OH)2-HP-1 / 2 / 3 are shown below. Figure 1 The image shows 883cm. -1 and 447cm -1 The peaks at each location are attributed to O2. 2- The tensile and stretching vibrations of OO in Mg-O-Mg demonstrate that the material surface is loaded with O2 after H2O2 modification. 2- Material-loaded O2 2-Peroxides can undergo photochemical reactions under ultraviolet light irradiation to generate hydroxyl radicals: H₂O₂ + hν (254 nm) → 2H₂O This promotes the degradation of pollutants.

[0046] Example 2: This application also discloses the use of H2O2-modified Mg-MOF derivative oxides for wastewater treatment. Based on the above-mentioned method for preparing H2O2-modified Mg-MOF derivative oxides, the hydrogen peroxide-modified Mg-MOF material can utilize sunlight to degrade organophosphorus compounds and recover orthophosphorus compounds through resource recovery, while simultaneously treating aquaculture wastewater for sterilization and algae removal. Specifically, the hydrogen peroxide-modified Mg-MOF material provided in this application utilizes surface-loaded O2... 2- H2O2 is slowly released in water to construct a Fenton-like system for synergistic effects, simultaneously driving the photocatalytic oxidation of organophosphorus ATP, the adsorption, fixation and recovery of orthophosphorus, and the sterilization and algae removal in wastewater.

[0047] The catalytic oxidation removal capacity of pollutants by MOF-Mg(OH)2-HP-1 / 2 / 3 modified with different concentrations of hydrogen peroxide was compared. The pollutant removal capacity of MOF-Mg(OH)2-HP-3 reached 100% after 90 min. Figure 2 Compared to other materials, the removal capacity was improved by 36%-38%. Kinetic fitting showed that the kinetic fitting parameters of MOF-Mg(OH)2-HP-3 were 6.13 times that of MOF-Mg(OH)2-HP-1 and 6.45 times that of MOF-Mg(OH)2-HP-2. Figure 3 Therefore, MOF-Mg(OH)2-HP-3 will be used as the research object in subsequent embodiments and will be referred to as MOF-Mg(OH)2-HP for short.

[0048] The active oxygen content of Mg(OH)₂-HP was determined to be 14.16 ± 1.3 wt% using potassium permanganate redox titration, and the active oxygen content of MOF-Mg(OH)₂-HP was determined to be 19.76 ± 1.1 wt%. (Since this experiment was conducted in a darkroom, interference from other photoactive substances was eliminated; therefore, the titration result for active oxygen is the material's O₂ content.) 2- The content indicates that MOF-Mg(OH)2-HP contains more O2 than Mg(OH)2-HP. 2- This demonstrates that the peroxide content affects the catalytic effect.

[0049] X-ray photoelectron spectroscopy (XPS) spectra of Mg(OH)₂-HP and MOF-Mg(OH)₂-HP are shown below. Figure 4-6 The O 1s fine spectrum indicates that oxygen in the material is present in the form of hydroxyl oxygen (O). -OH ), adsorbed oxygen (O ads) and bound oxygen (O lat ) exists, where O ads / O lat The value can determine the oxygen vacancy content of the material. The Mg 2p fine spectrum shows that MOF-Mg(OH)2-HP has a higher binding energy than Mg(OH)2-HP, proving that the MOF-derived material has a lower electron cloud density. The electron spin resonance (EPR) fitting spectra of the two materials (…) Figure 7 A strong signal was observed at g=2.008 in both results. Since the standard g value for a single-electron oxygen vacancy is typically between 2.000 and 2.004, and EPR detects delocalized unpaired electrons on the material surface, the g value in the fitted data deviates from the standard oxygen vacancy value. This result demonstrates that simple hydrogen peroxide modification can generate oxygen defects on the surface of commercially available magnesium oxide, which originally lacked oxygen vacancies. Furthermore, the generation of delocalized lone pairs can alter the electron configuration of the material surface, thereby increasing the material's pollutant oxidation capacity. The presence of oxygen vacancies can simultaneously mediate both radical and non-radical pathways for pollutant oxidation, and enhance pollutant adsorption by altering the adsorption configuration of the base material, significantly reducing the reaction energy barriers of both radical and non-radical pathways. This advantage is further amplified by the appearance of delocalized electrons on the material surface, further improving the photoelectric conversion efficiency. These factors enable this composite material to catalytically oxidize organophosphorus compounds and adsorb and recover inorganic phosphorus using energy input from sunlight.

[0050] Mg(OH)₂-HP and MOF-Mg(OH)₂-HP were placed under sunlight and in a shaded chamber, respectively, and the removal rate of pollutants at each time point was measured. Figure 8 (a) It was found that the removal rates of Mg(OH)2-HP and MOF-Mg(OH)2-HP were 33.58% and 39.98% respectively under dark conditions for 90 min, while the removal rates of pollutants by both under sunlight were 59.75% and 100% respectively, representing an improvement of 20 and 60 percentage points respectively compared to the dark conditions. This indicates that sunlight provides more suitable reaction conditions for both materials, therefore subsequent experiments were all conducted under sunlight. The kinetic reaction parameters of MOF-Mg(OH)2-HP under sunlight were 7.55 times that of Mg(OH)2-HP (…). Figure 8 (b) demonstrates that MOF-Mg(OH)2-HP exhibits superior photocatalytic performance compared to Mg(OH)2-HP. This is attributed to the abundant free radicals formed by oxygen vacancies on the MOF-Mg(OH)2-HP surface under sunlight irradiation and the presence of O2 on the material surface. 2- The H2O2 generated by hydrolysis oxidizes pollutants, i.e., photo-Fenton-like oxidation.

[0051] The dosage of MOF-Mg(OH)2-HP was adjusted to 0.1-1 g / L. The experimental results and kinetic fitting results are as follows: Figure 8 As shown in (c)-(d), when the dosage is greater than 0.4 g / L, the material can achieve a 100% removal rate of pollutants within 1.5 h, and the reaction kinetic constant reaches its maximum (k = 0.14527 min) when the dosage is 1 g / L. -1 The reason is that increasing the amount of material added is equivalent to directly increasing the O2 in the system. 2- The amount of H2O2 released through hydrolysis accelerates the oxidation of pollutants. However, increasing the concentration from 0.4 g / L to 1 g / L results in a kinetic constant difference of only 1.93 times. Therefore, considering economic costs, in this example, a dosage of 0.4 g / L is preferred to achieve 100% degradation. Subsequent examples will all be conducted at this dosage.

[0052] Regarding the effect of solution pH on the oxidation performance of MOF-Mg(OH)2-HP, this example prepared solutions with pH=5 (initial pH of the contaminant solution), 7, 9, and 11. The results are as follows. Figure 8 As shown in (e)-(f), the catalyst achieves 100% removal efficiency for pollutants at pH=5, and its catalytic activity gradually decreases with increasing pH; that is, the reaction kinetic parameters at pH=5 are 8.70 times those at pH=11. This is because the OH-... - As the concentration gradually increases, the oxidation potential of free radicals decreases, and the oxidation of pollutants is inhibited. However, under acidic conditions, the H2O2 generated by the hydrolysis of materials can be more effectively activated. OH, thereby oxidizing pollutants.

[0053] The effects of different concentrations of coexisting ions and HA on the performance of MOF-Mg(OH)2-HP are as follows: Figure 8 As shown in (g)-(h), the results indicate that neither the coexisting anions and cations at this concentration affect the photo-Fenton-like oxidation system of the material. However, the presence of HA significantly reduces catalyst performance; after adding 70 mg / L of HA, the pollutant oxidation rate decreased to 75.44%. This is because HA adsorption on the active sites of the material affects the generation of active substances. Furthermore, the combination of HA with metal ions makes it easier for HA to quench generated free radical intermediates and hydroxyl radicals produced by the decomposition of H2O2, ultimately reducing the generation of active substances. Additionally, the dark-colored HA dispersed in the water affects the transmittance of sunlight, thus reducing the photocatalytic performance of the material. Therefore, in this example, hydrogen peroxide-modified Mg-MOF material is preferred for degrading organophosphorus ATP in aquaculture wastewater with no or low HA concentrations.

[0054] The MOF-Mg(OH)2-HP was recycled four times in a 10 mg P / L ATP solution. The pollutant removal capacity is shown in the figure. Figure 8 (i) The pollutant removal efficiency after the fourth use was 65.39%. The decrease in oxidation capacity is due to the following reasons: During repeated use, the MgO2 on the surface is gradually consumed, transforming the system from a photo-Fenton-like system to a photocatalytic system, thus reducing the oxidation capacity. Phosphorus formed by ATP oxidation adsorbs onto the material surface, occupying active sites and reducing the generation of active substances under light. Furthermore, Mg gradually precipitates from the material, and the reduction in active sites after lattice disruption further decreases the material's ability to degrade pollutants. Therefore, in this example, the hydrogen peroxide-modified Mg-MOF material is preferred for the harmless treatment of aquaculture wastewater and can be recycled less than four times.

[0055] The oxidative removal capacity of MOF-Mg(OH)2-HP for other organophosphates was verified using β-glycerophosphate (β-GA) and phytic acid (IP6) at the same P concentration (10 mg P / L) as the ATP solution. Figure 9 The results showed that under the optimal conditions explored above (pH=5, dosage 0.4 g / L), the material could achieve 100% oxidation removal capacity for both types of organophosphorus pollutants with a phosphorus concentration of 10 mg P / L, proving that the photo-Fenton-like system formed by the material has a wide range of oxidation removal capacity for organophosphorus pollutants in water.

[0056] This application provides a MOF-Mg(OH)2-HP material that produces abundant active substances under light irradiation. Simultaneously, the MgO2 adhering to the material surface can hydrolyze to release H2O2, which can kill bacteria in aquaculture wastewater. Bactericidal experiments were conducted using local dairy farm wastewater and fishpond water from the experimental station, and the results are as follows... Figure 8 As shown in (j)-(k). After the addition of the material, the number of viable bacteria in both types of aquaculture wastewater continued to decrease. Within 3 hours, it killed 92.84% and 96.47% of E. coli in dairy farm wastewater and fishpond water, respectively, demonstrating excellent bactericidal effects. It can be applied to simultaneously kill bacteria and purify water quality while recovering phosphorus from aquaculture wastewater. The photoactive substance H2O2 produced by the hydrolysis of the material can also kill algae in the water by oxidizing the biofilm. Chlorella was used as the experimental species to test the algicidal ability of the material, while a blank control was set up to exclude the influence of other factors on the results. Figure 8 (l)). The killing rate was fastest in the first 2 hours, then the killing rate slowed down and reached the highest mortality rate (98.69%) in 8 hours, which proves that the material has excellent killing ability against microalgae under sunlight. This is attributed to the fact that light promotes the production of active substances in the material and destroys the cell membrane structure.

[0057] The comparison of P element EDS scans before and after MOF-Mg(OH)2-HP adsorption is shown in the figure. Figure 10EDS scanning results showed that phosphorus was bound to the material surface after use, proving that non-reactive organophosphorus compounds that cannot be directly recovered were oxidized to orthophosphate by the photo-Fenton-like system and then adsorbed onto the material surface. FTIR comparison of MOF-Mg(OH)2-HP before and after use (…) Figure 11 It can be seen that 447cm -1 883cm -1 1047cm -1 and 1443cm -1 The peak intensity and area at the point are significantly reduced, indicating a decrease in the exposed OO, Mg-O-Mg, CO, and O-Mg-O bonds on the material surface. The reduced OO bond strength proves that MgO2 is consumed by the oxidation reaction, and Mg-O-Mg, CO, and O-Mg-O are converted to Mg-OH (3697 cm⁻¹) after use. -1 The material was observed to be at 573cm after use. -1 A new peak appeared, which is attributed to the formation of PO bonds, proving that the orthophosphate ions formed after the material catalytically oxidizes pollutants are mainly collected on the material surface through internal sphere complexation.

[0058] XPS was used to determine the changes in the elemental state of the MOF-Mg(OH)2-HP surface before and after the reaction. O 1s fine spectrum ( Figure 12 This indicates that the electron cloud shifts towards higher binding energies, suggesting electron transfer occurred after the adsorption of pollutants, and that the oxygen vacancy content increases. lat and O ads The transformation demonstrates that the instability of charge balance due to electron transfer is beneficial to improving catalytic activity, and also proves the good defect stability of the material. After catalysis, the charge of Mg 2p shifts towards the direction of lower binding energy ( Figure 13 The increased electron cloud density indicates that electrons from the adsorbed orthophosphate have transferred to Mg, suggesting that Mg is the adsorption binding site for P. EPR fitting images before and after material use ( Figure 14 The comparison reveals a shift in the g-value, from 2.008 to 2.007, attributed to the consumption of surface delocalized electrons obtained from hydrogen peroxide modification. The peak intensity decreased compared to before use, attributed to electron transfer during pollutant oxidation and simultaneous filling as orthophosphate recovery sites. In summary, the characterization analysis indicates that MOF-Mg(OH)2-HP can oxidize organophosphorus compounds and recover orthophosphates through the participation of oxygen vacancies on its surface.

[0059] The effect of active species type on photo-Fenton-like degradation is shown in Figure 15 Using the same volume and concentration of MeOH, EDTA-2Na, L-His, and BQ, ·OH was quenched, h + , 1 O2 and ·O2 - ( Figure 16-19 The study found that MOF-Mg(OH)2-HP generates more active substances than Mg(OH)2-HP, which is the main reason for the difference in oxidation performance between the two materials. The contribution of active substances generated by MOF-Mg(OH)2-HP is ranked as follows: ·O2 > h + >·OH> 1 O2. All four active substances were detected, and their peak intensities under light were significantly higher than those under darkness, indicating that light promotes the formation of active species. Compared to the system without any quencher, the light-Fenton-like system showed increased O2 activity under the same concentration and volume of quencher. - and h + As the main active species, ·OH and 1 O2 was a minor reactive species. UV-Vis diffuse reflectance analysis was performed on MOF-Mg(OH)2-HP and Mg(OH)2-HP. Figure 20 The study found that both materials are more easily excited in the ultraviolet (10-400 nm) band, with MOF-Mg(OH)2-HP showing better excitation performance than Mg(OH)2-HP at 300-500 nm. This indicates that ultraviolet sunlight can not only decompose peroxides to generate hydroxyl radicals, but also generate oxidative pollutants by activating the photochemical properties of materials. Analysis of the material's conduction band position using UV-Vis data (…) Figure 21 The intersection of the tangent line drawn from the linear portion of the curve and the line extended to the X-axis represents the band gap width (E). fb ), E of MOF-Mg(OH)2-HP and Mg(OH)2-HP fb The values ​​were 4.58 eV and 4.62 eV, respectively, indicating that MOF-based materials possess superior photoelectric response capabilities. Under sunlight irradiation, they accelerate electron-hole separation and promote electron transfer, thereby generating a series of active substances. The valence band position of the material was analyzed using XPS valence band spectroscopy. Figure 22 The valence band potential (E) of the material is obtained by extending the tangent of the first linear segment of the curve. VB ), E of MOF-Mg(OH)2-HP and Mg(OH)2-HP VB These are 2.36 eV and 2.68 eV respectively, higher than the standard redox potential of ·OH / H2O (2.24 eV), therefore the h in the valence band... + The surface of the oxidizing material can be hydrolyzed to produce H2O2, generating ·OH, which in turn oxidizes pollutants. fb With E VB The difference can be used to obtain the conduction band potential (E). CB ), E of the two materials CB The values ​​are -2.22 eV and -1.94 eV, respectively. The E values ​​for both are... CB All are higher than O2 / ·O2 -The standard redox potential is -0.33 eV, therefore electrons in the conduction band can directly react with O2 to generate ·O2. - Analysis of photogenerated electrons in the valence band through instantaneous photocurrent response. - / h + Separation efficiency ( Figure 23 The instantaneous photocurrent of MOF-Mg(OH)2-HP was significantly higher than that of Mg(OH)2-HP, indicating that the superior catalytic performance of MOF-derived modified materials is due to the improvement of photogenerated electrons. - / h + Separation efficiency was achieved. The electrical properties of the material were investigated using electrochemical impedance spectroscopy and linear sweep voltammetry. Figure 24-25 MOF-Mg(OH)2-HP has a smaller arc diameter than Mg(OH)2-HP, indicating that MOF-derived modified materials have lower electrical impedance, thereby accelerating electron transfer efficiency.

[0060] In summary, the hydrogen peroxide-modified Mg-MOF material provided in this application introduces O2 onto the material surface. 2- The active components endow it with a large specific surface area, abundant oxygen vacancies, and high reactive oxygen species content, thereby significantly enhancing its catalytic performance. This material can slowly release H2O2 into water to construct a Fenton-like system and generate photocatalytically active species under sunlight, forming a synergistic oxidation mechanism to achieve efficient degradation of non-reactive organophosphates (such as ATP) while reducing dependence on external energy and reagents. Furthermore, the material can adsorb and fix the orthophosphate generated during degradation, achieving integrated treatment of pollutant removal and phosphorus resource recovery. In addition, the material also has bactericidal and algaecidal functions, synergistically reducing eutrophication and biosafety risks in water bodies. It operates under relatively mild conditions and has a certain degree of recyclability, providing a novel synergistic solution for the green recycling and harmless treatment of pollutants.

[0061] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing H2O2-modified Mg-MOF-derived oxides, characterized in that, Includes the following steps: S1. Dissolve 10-15 mmol of MgNO3·6H2O and 3-5 mmol of AA in a mixed solution consisting of 50-100 mL of DMF, 2-5 mL of EtOH and 2-5 mL of deionized water. S2. After dissolving, add to a reaction vessel and heat. After cooling, collect the crystals. S3. Calcination at high temperature to produce nano-metal oxide MOF-MgO; S4. Weigh 0.1g of MOF-MgO, mix it with 2-30% H2O2, stir magnetically under light for 2-4 hours, wash with pure water, collect by vacuum filtration, and dry to obtain hydrogen peroxide modified Mg-MOF material, the surface of which is loaded with O2. 2- .

2. The method for preparing H2O2-modified Mg-MOF-derived oxides according to claim 1, characterized in that, Step S2 includes: After being dissolved by ultrasonic treatment for several hours, the solution is added to a reaction vessel and heated in an oven at a temperature below 200°C for 12-48 hours. After cooling, the crystals are collected. Wash with DMF and EtOH 2-6 times respectively, and dry in a vacuum drying oven at 55-100℃ for 8-12 hours.

3. The method for preparing H2O2-modified Mg-MOF-derived oxides according to claim 2, characterized in that, In step S3, the temperature is raised to 600-650℃ in a muffle furnace at a heating rate of 5℃ / min, and calcined in air atmosphere for 6-10 hours to produce nano-metal oxide MOF-MgO.

4. The method for preparing H2O2-modified Mg-MOF-derived oxide according to any one of claims 1-3, characterized in that, In step S4, 0.1-0.5g of MOF-MgO is weighed and mixed with H2O2 at a concentration of 2-30%. The mixture is magnetically stirred under light for 2-4 hours, washed with pure water, filtered and collected, and dried at 50-60℃ to obtain hydrogen peroxide modified Mg-MOF material.

5. The use of H2O2-modified Mg-MOF-derived oxide for wastewater treatment, based on the preparation method of H2O2-modified Mg-MOF-derived oxide according to claim 1, characterized in that, The hydrogen peroxide-modified Mg-MOF material can utilize sunlight to degrade organic phosphorus and recover orthophosphorus resources, while simultaneously sterilizing and removing algae from aquaculture wastewater.

6. The use of the H2O2-modified Mg-MOF-derived oxide for wastewater treatment according to claim 5, characterized in that, The hydrogen peroxide-modified Mg-MOF material is modified by surface loading of O2. 2- H2O2 is slowly released in water to construct a Fenton-like system for synergistic effects, simultaneously driving the photocatalytic oxidation of organophosphorus ATP, the adsorption, fixation and recovery of orthophosphorus, and the sterilization and algae removal in wastewater.

7. The use of the H2O2-modified Mg-MOF-derived oxide for wastewater treatment according to claim 6, characterized in that, The hydrogen peroxide-modified Mg-MOF material is added at a dosage of 0.4-1 g / L. It degrades organophosphorus ATP and recovers orthophosphorus in an environment of pH=5, while simultaneously sterilizing and removing algae from aquaculture wastewater.

8. The use of H2O2-modified Mg-MOF-derived oxide for wastewater treatment according to claim 7, characterized in that, The hydrogen peroxide-modified Mg-MOF material degrades organophosphorus ATP in aquaculture wastewater without HA.

9. The use of the H2O2-modified Mg-MOF-derived oxide for wastewater treatment according to claim 6, characterized in that, The hydrogen peroxide-modified Mg-MOF material can harmlessly treat aquaculture wastewater and allow it to be recycled less than four times.

Images