A method for activating persulfate degradation of acetaminophen using Fe-N4 coordinated porphyrin MOF catalysts

Abstract

The application discloses a method for degrading acetaminophen by activating persulfate with a porphyrin-based MOFs catalyst with Fe-N4 coordination, which is characterized by activating persulfate with a porphyrin-based MOFs catalyst with Fe-N4 coordination to degrade water containing acetaminophen, wherein the porphyrin-based MOFs catalyst with Fe-N4 coordination is prepared from a porphyrin metal organic framework and a ferric salt through a solvothermal reaction. The method can realize 100% rapid degradation of acetaminophen within 6 minutes, and has the advantages of simple process, convenient operation, small amount of catalyst and oxidant, high degradation efficiency, good removal effect, wide application range, environmental friendliness and the like, and has important significance for acetaminophen wastewater treatment.

Description

Technical Field

[0001] This invention belongs to the field of advanced oxidation treatment of environmental pollutants, and specifically relates to a method for activating persulfate degradation of acetaminophen using Fe-N4 coordinated porphyrin MOF catalysts. Background Technology

[0002] Acetaminophen is a widely used antipyretic and analgesic drug. Due to its large-scale production and incomplete degradation, it has become one of the most frequently detected organic pollutants in aquatic environments. Wastewater containing acetaminophen and some of its degradation byproducts can pose threats to aquatic organisms and the ecological environment, and also have endocrine-disrupting effects, potentially inducing adverse effects such as genotoxicity and hepatotoxicity. Therefore, developing efficient acetaminophen wastewater purification technologies is particularly important. Advanced persulfate-based oxidation processes, with their advantages of simple operation and strong oxidizing capacity, have been widely used in the treatment of recalcitrant organic pollutants.

[0003] Currently, PMS activation methods can be divided into two main categories: homogeneous activation and heterogeneous activation. Homogeneous activation, due to its reliance on external energy input or transition metal ions, suffers from high energy consumption and is prone to secondary pollution. In contrast, heterogeneous activation, through the interaction of active sites on the surface of the solid catalyst with persulfate, not only facilitates recovery and prevents metal ion leaching but also significantly reduces energy consumption, making it green and efficient.

[0004] Metal-organic frameworks (MOFs) are a new type of porous material. Among them, porphyrin-based MOFs with Zn, Cd, Ni, In, or Zr as the metal center have become a research hotspot due to their advantages such as large specific surface area, tunable structure, and abundant active sites. Porphyrin-based MOFs (Zn, Cd, Ni, In, or Zr) have porphyrin structures similar to the active centers of natural enzymes, which can firmly bind metal ions to form catalytically active sites. However, unmodified porphyrin-based MOFs (Zn, Cd, Ni, In, or Zr) have limited activation activity in PMS and require external energy to function. At the same time, some modified MOFs lack stability in aqueous environments, and after long-term use, there is significant leaching of metal ions, leading to secondary pollution problems and a decline in catalytic performance. Therefore, it is necessary to effectively modify porphyrin-based MOFs (Zn, Cd, Ni, In, or Zr) to maintain high activation capacity while reducing metal ion leaching without external energy. This is of great significance for the efficient activation of persulfate and the efficient removal of acetaminophen from water. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a method for degrading acetaminophen by activating persulfate using Fe-N4 coordinated porphyrin MOFs catalyst, which is simple in process, convenient in operation, requires less catalyst and oxidant, has high degradation efficiency, good removal effect, wide applicability, and is environmentally friendly.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution.

[0007] A method for activating persulfate to degrade acetaminophen using a Fe-N4 coordinated porphyrin-based MOF catalyst, wherein the Fe-N4 coordinated porphyrin-based MOF catalyst is used as an activator to activate persulfate to degrade water containing acetaminophen; the Fe-N4 coordinated porphyrin-based MOF catalyst is prepared by solvothermal reaction of porphyrin-based metal-organic frameworks and iron salts.

[0008] A further improvement to the above method is the preparation method of the Fe-N4 coordinated porphyrin-based MOFs catalyst, which includes the following steps: mixing a porphyrin-based metal-organic framework, an iron salt, and an organic solvent, and carrying out a solvothermal reaction to obtain the Fe-N4 coordinated porphyrin-based MOFs catalyst.

[0009] In a further improvement to the above method, the temperature of the solvothermal reaction is 100℃~130℃, and the time of the solvothermal reaction is 8h~12h.

[0010] In a further improvement to the above method, the mass ratio of the porphyrin-based metal-organic framework to the iron salt is 1 to 2.5:4.

[0011] In a further improvement to the above method, the mass ratio of the porphyrin-based metal-organic framework to the iron salt is 1.5 to 2:4.

[0012] The above method is further improved in that the iron salt is ferric nitrate or ferric chloride, the organic solvent is N,N-dimethylformamide, the mixing is carried out under stirring conditions, the stirring time is 30 min to 60 min, and the solvothermal reaction is further improved by washing, drying and grinding the reaction product.

[0013] A further improvement to the above method is the preparation method of the porphyrin-based MOF catalyst, which involves mixing a metal salt, an organic ligand, and an organic solvent, adding acetic acid, and performing a hydrothermal reaction to obtain the porphyrin-based MOF catalyst. The metal salt is any one of Zn, Cd, Ni, In, and Zr salts; the organic ligand is any one of 5,10,15,20-tetra-(4-carboxyphenyl)porphyrin, 5,15-di(4-carboxyphenyl)-10,20-di(4-pyridyl)porphyrin, bis[3,5-di(4-carboxyphenyl)phenyl]porphyrin, and 5,10,15,20-tetra-(4-carboxymethoxy)phenylporphyrin; and the mass ratio of the metal salt to the organic ligand is 3.2–3.5:1.

[0014] A further improvement to the above method is that the degradation treatment involves mixing Fe-N4 coordinated porphyrin-based MOF catalysts with water containing acetaminophen, adding persulfate, and carrying out a catalytic degradation reaction to achieve the degradation of acetaminophen in the water.

[0015] In a further improvement to the above method, the ratio of the Fe-N4 coordinated porphyrin MOF catalyst to the acetaminophen-containing water is 0.05 g to 0.2 g: 1 L, the ratio of the persulfate to the acetaminophen-containing water is 0.3 mmol to 1 mmol: 1 L, and the initial concentration of acetaminophen in the acetaminophen-containing water is 8 mg / L to 10 mg / L.

[0016] In a further improvement to the above method, the initial pH value of the water containing acetaminophen is 3-9, the persulfate is potassium peroxymonosulfate, the mixing is carried out under stirring conditions, the stirring time is 30 min, the catalytic degradation reaction time is 2 min-8 min, and the catalytic degradation reaction temperature is 10℃-30℃. Compared with the prior art, the advantages of the present invention are as follows: (1) This invention provides a method for activating persulfate to degrade acetaminophen using a Fe-N4-coordinated porphyrin-based MOF catalyst. The Fe-N4-coordinated porphyrin-based MOF catalyst is used as an activator to activate persulfate for the degradation of acetaminophen-containing water. The Fe-N4-coordinated porphyrin-based MOF catalyst is prepared from porphyrin-based metal-organic frameworks and iron salts via a solvothermal reaction. The Fe-N4-coordinated porphyrin-based MOF catalyst used in this invention, on the one hand, uses the Fe-N4 metal porphyrin active site as an electron bridge, allowing the degradation of acetaminophen by Fe... 3+ / Fe 2+The recycling mechanism transfers electrons from pollutants to PMS, continuously generating various reactive oxygen species, thus improving the electron transfer capacity of the material and enhancing degradation efficiency. On the other hand, the Fe-N4 coordinated porphyrin-based MOF catalyst, with trivalent iron coordinating with the nitrogen atom at the porphyrin center, forms an Fe-N bond that effectively solves the problem of metal ion leaching, reducing the possibility of secondary pollution and making the catalyst structure more stable. The method of this invention can achieve 100% rapid degradation of acetaminophen within 6 minutes, possessing advantages such as simple process, convenient operation, small catalyst and oxidant dosage, high degradation efficiency, good removal effect, wide applicability, and environmental friendliness, making it of great significance for the treatment of acetaminophen wastewater.

[0017] (2) The method of the present invention, by optimizing the temperature of the solvothermal reaction to 100℃~130℃ and the time to 8h~12h, can break the intermolecular forces of porphyrin MOFs and force Fe 3+ By inserting Fe-N4 coordinate bonds into the center of the porphyrin ring and forming stable Fe-N4 coordination bonds with the N atom, Fe-N4 coordinated porphyrin-based MOF catalysts with better stability and higher catalytic activity can be obtained. However, if the solvothermal reaction time is too short, it is difficult to form stable Fe-N4 coordination bonds in the catalyst. Fe is mainly fixed on the porphyrin-based MOFs by physical adsorption or very weak coordination. The binding force between Fe and the support is weak (non-chemical bonding). In strongly oxidizing persulfate systems, Fe easily detaches from the support and enters the degradation system, forming homogeneous catalysis. This not only makes catalyst recovery difficult and prone to secondary pollution, but also leads to a rapid decline in catalytic activity due to Fe loss. Simultaneously, Fe in the catalyst may exist in the form of Fe(OH)3 colloids, Fe2O3 nanoparticles, or simple carboxyl coordination. Although these forms of Fe have certain peroxidase-like activity, their electron transfer ability is far weaker than that of the Fe-N4 structure, and they cannot efficiently activate persulfate to generate sulfate radicals (SO42-). This leads to a significant reduction in the catalytic activity of the catalyst. (3) The method of the present invention, by optimizing the mass ratio of porphyrin-based metal-organic framework to iron salt to 1–2.5:4, particularly when the mass ratio is 1.5–2:4, can promote the formation of Fe-N4 coordination bonds, thereby obtaining Fe-N4 coordinated porphyrin-based MOF catalysts with higher catalytic activity. If the amount of iron salt is too small, it will cause Fe… 3+ Insufficient Fe-N4 coordination bonds make it difficult to form enough Fe-N4 coordination bonds, thus reducing the catalytic activity of the catalyst. Attached Figure Description

[0018] Figure 1 The images show SEM images of MOFs (Zr) and Fe-N4-MOFs (Zr) in Embodiment 1 of the present invention.

[0019] Figure 2 These are TEM images of MOFs (Zr) and Fe-N4-MOFs (Zr) in Embodiment 1 of the present invention.

[0020] Figure 3 This is an elemental distribution diagram of Fe-N4-MOFs (Zr) in Embodiment 1 of the present invention.

[0021] Figure 4 The images show the XRD patterns of MOFs (Zr), Fe-N4-MOFs (Zr), and Fe-N4-MOFs (Zr) 1 in Embodiment 1 of the present invention.

[0022] Figure 5 The Fourier transform infrared spectra of MOFs (Zr), Fe-N4-MOFs (Zr) and Fe-N4-MOFs (Zr) 1 in Example 1 of the present invention are shown.

[0023] Figure 6 This is the XPS spectrum of Fe-N4-MOFs (Zr) in Example 1 of the present invention.

[0024] Figure 7 The graph shows the degradation effect of acetaminophen under different reaction systems in Example 1 of the present invention.

[0025] Figure 8 The graph shows the degradation effect of Fe-N4-MOFs (Zr) activated persulfate on acetaminophen in Example 2 of this invention with different catalyst addition amounts.

[0026] Figure 9 This is a graph showing the degradation effect of Fe-N4-MOFs (Zr) activated persulfate on acetaminophen in Example 3 of the present invention with different persulfate addition amounts.

[0027] Figure 10 The graph shows the degradation effect of Fe-N4-MOFs (Zr) activated persulfate on acetaminophen under different pH conditions in Example 4 of this invention.

[0028] Figure 11 This image shows the degradation effect of Fe-N4-MOFs (Zr) activated persulfate on acetaminophen under different ion interference conditions in Example 5 of the present invention. Detailed Implementation

[0029] The present invention will be further described below with reference to the accompanying drawings and specific preferred embodiments, but this does not limit the scope of protection of the present invention. All materials and instruments used in the following embodiments are commercially available.

[0030] Example 1: A method for activating persulfate degradation of acetaminophen using a Fe-N4 coordinated porphyrin-based MOF catalyst according to the present invention includes the following steps: Weigh 5 mg of Fe-N4 coordinated porphyrin-based MOF catalyst (Fe-N4-MOFs (Zr)) and add it to 100 mL of 10 mg / L acetaminophen solution (initial pH of the solution is 5.8). Stir for 30 min to reach adsorption-desorption equilibrium. Then, add potassium persulfate (chemical formula: KHSO5) (PMS) to make the concentration of PMS in the system 0.3 mM. Catalytic degradation reaction is carried out at room temperature (10℃~30℃) for 6 min to complete the degradation of acetaminophen in water.

[0031] Control group 1 (MOFs (Zr)): Fe-N4-MOFs (Zr) was replaced with MOFs (Zr), and all other conditions were the same.

[0032] Control group 2 (Fe-N4-MOFs (Zr) 1): Fe-N4-MOFs (Zr) was replaced with Fe-N4-MOFs (Zr) 1, and all other conditions were the same.

[0033] Control group 3 (ferric chloride): Fe-N4-MOFs (Zr) were replaced with ferric chloride, and all other conditions were the same.

[0034] In the catalytic degradation reaction, 1 mL of reaction solution was taken at time points of 0 min (adsorption 30 min), 1 min, 2 min, 3 min, 4 min, 5 min, and 6 min, filtered through a 0.22 μm filter, and added to a liquid chromatography vial containing 200 μL of 100 mM sodium thiosulfate solution. The concentration of acetaminophen in the solution was detected by liquid chromatography.

[0035] In this embodiment, the preparation method of the Fe-N4 coordinated porphyrin-based MOF catalyst (Fe-N4-MOFs (Zr)) includes the following steps: (1) Weigh 120 mg of zirconium oxychloride octahydrate and add it to 50 mL of N,N-dimethylformamide. Stir for 30 min to disperse and suspend it evenly to obtain suspension A.

[0036] (2) Add 35 mg of 5,10,15,20-tetra(4-carboxyphenyl)porphyrin to the above suspension A, stir for 10 min at 25 °C, and then add 12.5 mL of acetic acid to obtain suspension B.

[0037] (3) The above suspension B was hydrothermally reacted at 65°C for 72 hours. After washing, drying and grinding, porphyrin-based metal-organic frameworks were obtained, denoted as MOFs (Zr).

[0038] (4) Weigh 200 mg of the above MOFs (Zr) and 400 mg of ferric chloride, add them to 40 mL of N,N-dimethylformamide, stir for 30 min to disperse and suspend them evenly, and react them in a solvothermal manner at 120 °C for 12 h under stirring conditions. After washing with methanol, dry and grind to obtain Fe-N4 coordinated porphyrin MOFs catalyst, denoted as Fe-N4-MOFs (Zr).

[0039] In this embodiment, the preparation method of Fe-N4-MOFs (Zr) 1 is basically the same as the preparation method of Fe-N4 coordinated porphyrin MOFs catalyst (Fe-N4-MOFs (Zr)), the only difference being that in step (4), the amount of MOFs (Zr) used is 100mg.

[0040] After the catalytic degradation reaction was completed, ICP-OES analysis showed that no iron leaching was detected in the system.

[0041] Figure 1 The images show SEM images of MOFs (Zr) and Fe-N4-MOFs (Zr) in Embodiment 1 of the present invention. Figure 1 In the image, the left figure shows MOFs (Zr), and the right figure shows Fe-N4-MOFs (Zr). From... Figure 1 It can be seen that the Fe-N4-MOFs (Zr) of the present invention has a similar structure to MOFs (Zr), and the size is distributed in the range of 3-5 micrometers. It can be seen that the doping of iron does not destroy the structure of the material.

[0042] Figure 2 These are TEM images of MOFs (Zr) and Fe-N4-MOFs (Zr) in Embodiment 1 of the present invention. Figure 2 In the middle, the left image shows MOFs (Zr), and the middle and right images show Fe-N4-MOFs (Zr). From... Figure 2 It is known that the Fe-N4-MOFs (Zr) and MOFs (Zr) of the present invention both exhibit a roughly cubic crystal structure with a lattice fringe measurement of 0.31 nm.

[0043] Figure 3 This is an elemental distribution diagram of Fe-N4-MOFs (Zr) in Embodiment 1 of the present invention. From... Figure 3 It can be seen that C, O, N, Zr and Fe are evenly distributed, indicating that the synthesis of Fe-N4-MOFs (Zr) is effective.

[0044] Figure 4The images show the XRD patterns of MOFs (Zr), Fe-N4-MOFs (Zr), and Fe-N4-MOFs (Zr) 1 in Embodiment 1 of the present invention. Figure 4 It can be seen that the crystal structure of the catalyst remains intact under different iron doping levels, and the doped iron does not form independent crystalline impurities.

[0045] Figure 5 The images show the Fourier transform infrared spectra of MOFs (Zr), Fe-N4-MOFs (Zr), and Fe-N4-MOFs (Zr) 1 in Embodiment 1 of the present invention. Figure 5 It is known that Fe-N4-MOFs (Zr) and Fe-N4-MOFs (Zr) 1 both formed Fe-N bonds, which provides direct evidence for the formation of Fe-N4 metalloporphyrin active sites.

[0046] Figure 6 This is the XPS spectrum of Fe-N4-MOFs (Zr) in Example 1 of this invention. From... Figure 6 It can be seen that in the 2p energy spectrum of Fe, the peaks at 709.9 eV and 723.1 eV correspond to Fe 2+ 2p 3 / 2 and 2p 1 / 2 The peaks at 711.5 eV and 725.0 eV are attributed to Fe. 3+ 2p 3 / 2 and 2p 1 / 2 Orbit. Peak fitting analysis shows Fe 3+ with Fe 2+ The relative area ratios were 64.9% and 35.1%, respectively, indicating that Fe... 3+ This is the main coordination state of iron ions in Fe-N4 coordinated porphyrin-based MOF catalysts. Additionally, three characteristic peaks were observed in the 1s energy spectrum of O at 532.5 eV, 531.1 eV, and 529.5 eV, corresponding to C–OH, C=O, and Zr–O bonds, respectively.

[0047] Figure 7 This image shows the degradation effect of acetaminophen under different reaction systems in Example 1 of the present invention. Figure 7 It can be seen that within 6 minutes, the Fe-N4-MOFs (Zr) group can completely degrade acetaminophen; the degradation rates of acetaminophen by the MOFs (Zr) group, Fe-N4-MOFs (Zr) 1 group and ferric chloride group are 28.93%, 83.42% and 14.54%, respectively.

[0048] It is evident that, under the conditions of an initial pH of 5.8, a PMS concentration of 0.3 mM, and a catalyst dosage of 0.05 g / L, Fe-N4-MOFs (Zr) can degrade 100% of acetaminophen within 6 minutes. This demonstrates that Fe-N4-MOFs (Zr) exhibits excellent catalytic performance, efficiently activating persulfate to completely remove acetaminophen from water. Furthermore, the method of this invention uses lower doses of catalyst and oxidant, avoiding the problems of difficult catalyst recovery and secondary pollution caused by excessive oxidant addition.

[0049] Example 2: The effect of different catalyst addition amounts on the degradation of acetaminophen was investigated. Specifically, Fe-N4 coordinated porphyrin MOFs catalysts were used to activate persulfate to degrade acetaminophen, including the following steps: Weigh out 3 mg, 5 mg, 7 mg, and 9 mg of the Fe-N4 coordinated porphyrin MOF catalyst (Fe-N4-MOFs(Zr)) from Example 1, and add them to 100 mL and 10 mg / L of acetaminophen solution (the initial pH of the solution is 5.8), respectively. Stir for 30 min to reach adsorption-desorption equilibrium. Then, add potassium persulfate (PMS) to make the concentration of PMS in the system 0.3 mM, and carry out the catalytic degradation reaction for 6 min to complete the degradation of acetaminophen in the water.

[0050] Figure 8 This image shows the degradation effect of Fe-N4-MOFs (Zr) activated persulfate on acetaminophen in Example 2 of this invention with different catalyst addition amounts. Figure 8 It can be seen that the dosage of Fe-N4-MOFs (Zr) catalyst has a significant positive effect on the degradation of acetaminophen.

[0051] Example 3: The effect of different persulfate addition amounts on the degradation of acetaminophen was investigated. Specifically, the degradation of acetaminophen was carried out by activating persulfate with Fe-N4 coordinated porphyrin MOF catalyst, including the following steps: Five 5 mg portions of the Fe-N4 coordinated porphyrin MOF catalyst (Fe-N4-MOFs (Zr)) from Example 1 were weighed and added to 100 mL and 10 mg / L acetaminophen solutions (the initial pH of the solution was 5.8), respectively. The mixture was stirred for 30 min to reach adsorption-desorption equilibrium. Then, potassium persulfate (PMS) was added to make the concentrations of PMS in the system 0.1 mM, 0.2 mM, 0.3 mM, 0.4 mM and 0.5 mM, respectively. The catalytic degradation reaction was carried out for 6 min to complete the degradation of acetaminophen in the water.

[0052] Figure 9 This image shows the degradation effect of Fe-N4-MOFs (Zr) activated persulfate on acetaminophen in Example 3 of this invention with different persulfate addition amounts. Figure 9 It can be seen that when the amount of potassium persulfate is greater than 0.1 mM, acetaminophen can be completely degraded within 6 minutes, indicating that Fe-N4-MOFs (Zr) only requires a small amount of oxidant to efficiently degrade acetaminophen.

[0053] Example 4: The effect of different pH values ​​on the degradation of acetaminophen was investigated. Specifically, Fe-N4 coordinated porphyrin MOF catalysts were used to activate persulfate to degrade acetaminophen, including the following steps: Take 6 100 mL aliquots of acetaminophen solution (concentration of 10 mg / L, initial pH of 5.8), and adjust the pH of 5 aliquots of acetaminophen solution to 3, 5, 7, 9 and 11 respectively using 0.1 mol / L hydrochloric acid and sodium hydroxide solution. Add 5 mg of Fe-N4 coordinated porphyrin MOF catalyst (Fe-N4-MOFs (Zr)) from Example 1 to each aliquot, and stir for 30 min to reach adsorption-desorption equilibrium. Then, add potassium persulfate (PMS) to make the concentration of PMS in the system 0.3 mM, and carry out catalytic degradation reaction for 6 min to complete the degradation of acetaminophen in water.

[0054] Figure 10 This image shows the degradation effect of Fe-N4-MOFs (Zr) activated persulfate on acetaminophen under different pH conditions in Example 4 of this invention. Figure 10 It was found that the Fe-N4-MOFs (Zr) catalyst could completely degrade paracetamol at pH 7 and 9; the removal rates of paracetamol by the Fe-N4-MOFs (Zr) catalyst at pH 3, 5, and 11 were 97.13%, 99.01%, and 92.73%, respectively. The degradation efficiency decreased slightly when pH < 7, which may be due to the increased H⁺ concentration under acidic conditions. + With HSO5 - The OO groups (in the main form of PMS) form hydrogen bonds, thus hindering PMS activation. At pH 11, the degradation efficiency slightly decreases due to the self-decomposition of PMS and precipitation-induced deactivation of iron species. The results indicate that this system exhibits high ACE degradation efficiency over a wide pH range, demonstrating excellent pH tolerance. Therefore, the degradation system constructed from Fe-N4-coordinated porphyrin-based MOFs catalysts and PMS in this invention has a wide pH applicability range, achieving a degradation rate of over 97% for acetaminophen within a pH range of 3–9.

[0055] Example 5: The effects of different ion interference conditions on the degradation of acetaminophen were investigated. Specifically, the degradation of acetaminophen by persulfate was activated using a Fe-N4 coordinated porphyrin MOF catalyst, including the following steps: Six 5mg portions of the Fe-N4 coordinated porphyrin-based MOF catalyst (Fe-N4-MOFs (Zr)) from Example 1 were weighed and added to 100mL of 10mg / L acetaminophen solution (the initial pH of the solution was 5.8). Five of these portions were then added to 10mM sodium chloride, 10μM sodium sulfate, 10mM sodium carbonate, 10mM sodium nitrate, and 5mM humic acid, respectively. The mixture was stirred for 30min to reach adsorption-desorption equilibrium. Then, potassium persulfate (PMS) was added to make the concentration of PMS in the system 0.3mM, and the catalytic degradation reaction was carried out for 6min to complete the degradation of acetaminophen in the water.

[0056] Figure 11 This image shows the degradation effect of Fe-N4-MOFs (Zr) activated persulfate on acetaminophen under different ion interference conditions in Example 5 of this invention. Figure 11 It can be seen that adding sodium carbonate (CO3) 2- Sodium sulfate (SO4) 2- When acetaminophen is reacted with CO3 and humic acid (HA), the degradation rates are 74.76%, 92.75%, and 21.85%, respectively. 2- SO4 2- The presence of humic acid inhibited the degradation performance of Fe-N4 coordinated porphyrin-based MOF catalysts to varying degrees. This is because: CO3 2- It will react with SO4 in the system 2- • and •OH react; SO4 2- The degradation rate of acetaminophen is reduced by inhibiting PMS activation through competitive adsorption on the catalyst surface and complexation with metal centers; while the hydroxyl and carboxyl groups on the HA surface compete with acetaminophen for degradation, thus significantly reducing its degradation rate. In contrast, the degradation reaction system of this invention contains Cl - NO3 - When ions are present, there is almost no effect on the degradation rate of acetaminophen.

[0057] In summary, the method of activating persulfate degradation of acetaminophen using Fe-N4 coordinated porphyrin MOF catalyst of the present invention has significant advantages such as simple process, convenient operation, small amount of catalyst and oxidant, high degradation efficiency, good removal effect, wide applicability, and environmental friendliness. It can achieve efficient and thorough removal of acetaminophen from water, has high use value, and good application prospects.

[0058] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention using the methods and techniques disclosed above, or modify them into equivalent embodiments with equivalent changes, without departing from the spirit and technical essence of the present invention. Therefore, any simple modifications, equivalent substitutions, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall still fall within the protection scope of the technical solutions of the present invention.

Claims

1. A method for activating persulfate degradation of acetaminophen using a Fe-N4 coordinated porphyrin-based MOF catalyst, characterized in that, The method uses Fe-N4 coordinated porphyrin-based MOFs catalyst as an activator to activate persulfate to degrade water containing acetaminophen; the Fe-N4 coordinated porphyrin-based MOFs catalyst is prepared by solvothermal reaction of porphyrin-based metal-organic framework and iron salt as raw materials.

2. The method according to claim 1, characterized in that, The preparation method of the Fe-N4 coordinated porphyrin-based MOFs catalyst includes the following steps: mixing a porphyrin-based metal-organic framework, an iron salt, and an organic solvent, and carrying out a solvothermal reaction to obtain the Fe-N4 coordinated porphyrin-based MOFs catalyst.

3. The method according to claim 2, characterized in that, The temperature of the solvothermal reaction is 100℃~130℃, and the time of the solvothermal reaction is 8h~12h.

4. The method according to claim 3, characterized in that, The mass ratio of the porphyrin-based metal-organic framework to the iron salt is 1–2.5:

4.

5. The method according to claim 4, characterized in that, The mass ratio of the porphyrin-based metal-organic framework to the iron salt is 1.5 to 2:

4.

6. The method according to claim 5, characterized in that, The iron salt is ferric nitrate or ferric chloride, the organic solvent is N,N-dimethylformamide, the mixing is carried out under stirring conditions, the stirring time is 30 min to 60 min, and the following treatment is included after the solvothermal reaction: washing, drying and grinding the reaction product.

7. The method according to claim 6, characterized in that, The porphyrin-based MOF catalyst is prepared by mixing a metal salt, an organic ligand, and an organic solvent, adding acetic acid, and performing a hydrothermal reaction to obtain the porphyrin-based MOF catalyst. The metal salt is any one of Zn, Cd, Ni, In, and Zr salts, and the organic ligand is any one of 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin, 5,15-di(4-carboxyphenyl)-10,20-di(4-pyridyl)porphyrin, bis[3,5-di(4-carboxyphenyl)phenyl]porphyrin, and 5,10,15,20-tetrakis(4-carboxymethoxy)phenylporphyrin. The mass ratio of the metal salt to the organic ligand is 3.2 to 3.5:

1.

8. The method according to any one of claims 1 to 7, characterized in that, The degradation process involves mixing Fe-N4 coordinated porphyrin-based MOFs catalyst with water containing acetaminophen, adding persulfate, and carrying out a catalytic degradation reaction to achieve the degradation of acetaminophen in the water.

9. The method according to claim 8, characterized in that, The ratio of the Fe-N4 coordinated porphyrin MOF catalyst to the water containing acetaminophen is 0.05 g to 0.2 g: 1 L, the ratio of the persulfate to the water containing acetaminophen is 0.3 mmol to 1 mmol: 1 L, and the initial concentration of acetaminophen in the water containing acetaminophen is 8 mg / L to 10 mg / L.

10. The method according to claim 9, characterized in that, The initial pH of the water containing acetaminophen is 3-9, the persulfate is potassium peroxymonosulfate, the mixing is carried out under stirring conditions, the stirring time is 30 min, the catalytic degradation reaction time is 2 min-8 min, and the catalytic degradation reaction temperature is 10℃-30℃.

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