An interatomic distance adjustable iron atom catalyst, and a preparation method and application thereof

Abstract

The application provides an atomic distance adjustable iron atom catalyst and a preparation method and application thereof, and belongs to the technical field of wastewater treatment.The preparation method of the atomic distance adjustable iron atom catalyst is as follows: iron nitrate nonahydrate and aniline ligand are mixed and dissolved, then zeolite imidazole framework-8 is added and mixed, and then drying and dehydration are performed to obtain an iron atom catalyst precursor; the iron atom catalyst precursor is sequentially subjected to pyrolysis, acid pickling and drying and dehydration to obtain the iron atom catalyst; the preparation method is simple, has strong operability, has a large specific surface area, has a high antibiotic removal rate, has a wide pH application range, has a low iron ion leaching amount, is safe and stable, and has strong site regenerability; the iron atom catalyst can activate PMS and initiate multiple non-radical pathways, multiple oxidation pathways can be changed with the change of the iron atom distance, environmental interference can be effectively resisted, and the iron atom catalyst has a broad application prospect in the treatment of antibiotic pollutants in complex water quality.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, specifically relating to an iron atom catalyst with adjustable atomic spacing, its preparation method, and its application. Background Technology

[0002] Due to the overuse of antibiotics in industries such as medicine and aquaculture, large quantities of antibiotics remain in the aquatic environment due to their low biodegradability. The persistent and bioaccumulative nature of antibiotics leads to a continuous increase in resistant bacteria and resistance genes in the aquatic environment, threatening human health and the ecological environment. Simultaneously, the interference of complex water components in wastewater poses a severe challenge to the removal of antibiotics by conventional water treatment processes. Therefore, developing efficient, economical, safe, stable, and environmentally resistant water purification technologies is crucial.

[0003] Persulfate-based advanced oxidation technologies (PMS-AOPs) have significant advantages in removing recalcitrant organic pollutants. On one hand, PMS can be activated by catalysts to generate hydroxyl radicals with strong oxidizing power. · OH) and sulfate radicals (SO4) ·- This allows for the efficient oxidative degradation of pollutants. On the other hand, PMS can also be activated by catalysts to initiate processes including singlet oxygen (…). 1 Non-radical pathways, including those involving O2, high-valence metal-oxygen species (HV-Me), and electron transfer, selectively degrade electron-rich, recalcitrant organic pollutants while exhibiting strong resistance to environmental disturbances. The selective initiation of non-radical pathways holds promise for playing a significant role in removing antibiotic pollutants under complex water conditions, which is highly dependent on the site characteristics of the catalyst.

[0004] Single-atom catalysts (SACs) with unsaturated metal-Nx sites (M-Nx, where x is the nitrogen coordination number of the metal center) possess tunable site structures, which are beneficial for activating PMS and initiating non-radical pathways. Among them, iron-based SACs are green, safe, and inexpensive, and exhibit good binding affinity and electronic interactions with PMS molecules. However, due to limitations in existing synthetic methods, the site structure of iron-based SACs exhibits a degree of randomness, which is detrimental to controlling their catalytic activity and mechanism initiation in PMS. Therefore, a site-controllable single-atom catalyst is urgently needed. Summary of the Invention

[0005] In view of this, the present invention aims to provide an iron atom catalyst with adjustable interatomic spacing, its preparation method and application. The obtained catalyst achieves efficient degradation of antibiotics through the combined action of multiple non-radical pathways; it is not easily affected by water quality characteristics, has a wide pH range, is suitable for the treatment of recalcitrant organic pollutants under complex water quality conditions, and the preparation method is simple and applicable to industrial production.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] In a first aspect, the present invention provides a method for preparing an iron atom catalyst with adjustable interatomic spacing, comprising the following steps:

[0008] 1) Ferric nitrate nonahydrate was mixed and dissolved with aniline ligand, then zeolite imidazole framework-8 was added and mixed, and then dried and dehydrated to obtain an iron atom catalyst precursor.

[0009] 2) The iron atom catalyst precursor is subjected to pyrolysis, acid washing, and drying and dehydration in sequence to obtain the iron atom catalyst.

[0010] Based on Lewis's hard-soft acid-base theory, this invention utilizes the tendency of amino groups to form ionic bonds with hard Lewis acidic metals. Therefore, a molecular recognition strategy is employed to utilize organic molecules with varying amino group spacings to bind iron ions, assisting in the formation of an iron atom catalyst with tunable spacing. By regulating the non-radical pathway in the PMS system, antibiotic contaminants in complex water conditions can be efficiently removed.

[0011] Preferably, the preparation method of zeolite imidazole framework-8 in step 1) is as follows: 2-methylimidazole and zinc nitrate hexahydrate are dissolved in methanol respectively, and then the two solutions are mixed and subjected to standing, centrifugation, washing, drying and dehydration in sequence to obtain zeolite imidazole framework-8.

[0012] Preferably, the molar ratio of 2-methylimidazole to zinc nitrate hexahydrate is 1:4.

[0013] Preferably, the mixing time is 5-10 min, the settling time is 12-24 h, the centrifugation rate is 8000-10000 r / min, and the washing solvent is methanol.

[0014] Preferably, in step 1), the molar ratio of ferric nitrate nonahydrate to aniline ligand is 1:3.

[0015] Preferably, the aniline ligand is any one of o-phenylenediamine, p-phenylenediamine, or diphenylamine.

[0016] By employing the above technical solution and using different aniline ligands, the interatomic spacing can be adjusted, wherein the inter-amino spacing of o-phenylenediamine is approximately [value missing]. The amino spacing of p-phenylenediamine is approximately Using o-phenylenediamine as a ligand, a closely spaced iron atom catalyst initiates a non-radical pathway primarily based on HV-Me; using p-phenylenediamine as a ligand, a moderately spaced iron atom catalyst initiates a pathway primarily based on HV-Me. 1The non-radical pathway involving O2 and HV-Me mixtures; the initiation of the pathway by iron atom catalysts with larger interatomic spacings obtained using diphenylamine as a ligand; 1 Non-radical pathways mainly based on O2 and HV-Me, and free radical pathways mainly based on ·OH.

[0017] Preferably, the solvent in step 1) is methanol.

[0018] Preferably, in step 1), the mixing time of ferric nitrate nonahydrate and aniline ligand is 2-3 hours, and the mixing time of the mixed solution with zeolite imidazole framework-8 is 1-2 hours.

[0019] Preferably, in step 2), nitrogen is used as the protective gas in the pyrolysis step, the heating rate is 5-10℃ / min, the pyrolysis temperature is 800-1000℃, and the pyrolysis holding time is 2-3h.

[0020] Preferably, the pickling solution used in step 2) is a 0.5-1 mol / L H2SO4 solution, and the pickling time is 2-3 h.

[0021] Preferably, the drying and dehydration temperature in step 2) is 60-80°C, and the dehydration time is 12-24 hours.

[0022] Secondly, the present invention provides an iron atom catalyst with adjustable interatomic spacing, which is prepared by the above-described preparation method.

[0023] Thirdly, the present invention provides the application of the above-mentioned iron atom catalyst with adjustable atomic spacing in the activation of PMS to remove antibiotics from wastewater, characterized in that the antibiotics include tetracycline, bisphenol A, sulfamethoxazole or benzoic acid.

[0024] Preferably, the catalyst is added at a dosage of 0.025 g / L to 0.2 g / L, and the PMS concentration is 0.5 mmol / L to 3 mmol / L.

[0025] Preferably, the pH value of the reaction system for removing antibiotics from wastewater is 1-13, and the temperature of the reaction system is 25-30℃.

[0026] Preferably, the quenching agent for removing antibiotics from wastewater includes ethanol, tert-butanol, furfuryl alcohol, and methyl phenyl sulfoxide.

[0027] It contains at least the following beneficial technical effects:

[0028] (1) The present invention obtains an iron atom catalyst precursor by mixing and dissolving ferric nitrate nonahydrate with aniline ligand, then adding zeolite imidazole framework-8 and mixing, followed by drying and dehydration; the iron atom catalyst precursor is then subjected to pyrolysis, acid washing, and drying and dehydration to obtain an iron atom catalyst, which is prepared by a one-step calcination method. The synthesis process is simple.

[0029] (2) This invention utilizes Lewis soft and hard acid-base theory and molecular recognition strategy to bind ferric ions with aniline compounds with different amino distances as ligands, thereby achieving controllable adjustment of the distance between iron atoms.

[0030] (3) The catalyst raw materials of the present invention use ferric nitrate nonahydrate as the metal source and zeolite imidazole framework-8 as the substrate, which has the advantages of wide material sources and low cost.

[0031] (4) The iron atom catalyst prepared in this invention inherits the large specific surface area of ​​the zeolite imidazole framework-8 derived carbon, thereby exposing more active sites.

[0032] (5) The iron atom catalyst prepared by the present invention has only a slight decrease in catalytic effect after 4 cycles, has strong stability and good regenerability, and effectively reduces the environmental hazards caused by metal ion leaching.

[0033] (6) This invention achieves efficient degradation of antibiotics through the combined action of multiple non-free radical pathways. More than 90% of antibiotics can be removed in 15 to 20 minutes of reaction. It is not easily affected by water quality characteristics, has a wide pH range, is suitable for the treatment of recalcitrant organic pollutants under complex water quality conditions, and has broad application prospects. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0035] Figure 1 The graph shows the removal rate of TC by PMS activated by the catalysts prepared in Examples 1-5.

[0036] Figure 2 The graph shows the removal rate of TC by PMS activated by catalysts prepared at different pyrolysis temperatures in Examples 1 and 6-7.

[0037] Figure 3 The graph shows the removal rate of TC by PMS activated by catalysts with different aniline ligands prepared in Examples 1 and 8-9.

[0038] Figure 4 Transmission electron microscopy image of the catalyst prepared in Example 8;

[0039] Figure 5 Transmission electron microscopy image of the catalyst prepared in Example 1;

[0040] Figure 6 Transmission electron microscopy image of the catalyst prepared in Example 9;

[0041] Figure 7 X-ray diffraction patterns of the catalysts prepared in Examples 1 and 8-9;

[0042] Figure 8 Aberration-corrected high-angle annular dark-field scanning transmission electron microscope image of the catalyst prepared in Example 8;

[0043] Figure 9 Aberration-corrected high-angle annular dark-field scanning transmission electron microscope image of the catalyst prepared in Example 1;

[0044] Figure 10 Aberration-corrected high-angle annular dark-field scanning transmission electron microscope image of the catalyst prepared in Example 9;

[0045] Figure 11 The adsorption and desorption isotherms are shown for the catalysts prepared in Examples 1 and 8-9.

[0046] Figure 12 The graph shows the effect of catalyst dosage on the removal of TC by PMS activated by the catalyst prepared in Example 1.

[0047] Figure 13 The graph shows the effect of PMS concentration on the removal of TC by activating PMS with the catalyst prepared in Example 1.

[0048] Figure 14 The graph shows the effect of the initial pH value of the reaction system on the activation of PMS by the catalyst prepared in Example 1 to remove TC.

[0049] Figure 15 The graph shows the removal rates of different pollutants by the catalyst-activated PMS prepared in Example 8.

[0050] Figure 16 The graph shows the removal rates of different pollutants by PMS activated by the catalyst prepared in Example 1.

[0051] Figure 17 The graph shows the removal rates of different pollutants by the catalyst-activated PMS prepared in Example 9.

[0052] Figure 18The graph shows the removal rate of TC by activated PMS after the catalyst prepared in Example 8 was circulated 4 times and recalcined.

[0053] Figure 19 The graph shows the removal rate of TC by activated PMS after the catalyst prepared in Example 1 was circulated 4 times and recalcined.

[0054] Figure 20 The graph shows the removal rate of TC by activated PMS after the catalyst prepared in Example 9 was circulated 4 times and recalcined.

[0055] Figure 21 This is a quenching experiment diagram of the catalyst prepared in Example 8 activating PMS to remove TC;

[0056] Figure 22 This is a quenching experiment diagram of the catalyst prepared in Example 1 activating PMS to remove TC;

[0057] Figure 23 The diagram shows the quenching experiment of PMS activating the catalyst prepared in Example 9 to remove TC. Detailed Implementation

[0058] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0059] The terms “comprising” or “including” in this invention are open-ended descriptions that include the specified ingredients or steps described, as well as other specified ingredients or steps that do not materially affect them.

[0060] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0061] Where specific techniques or conditions are not specified in the examples, they shall be performed in accordance with the techniques or conditions described in the literature in this field, or in accordance with the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased through legitimate channels.

[0062] Example 1

[0063] This embodiment provides an iron atom catalyst with adjustable interatomic spacing, and the preparation steps are as follows:

[0064] 1) Under magnetic stirring, 5.95 g of 2-methylimidazole and 6.57 g of zinc nitrate hexahydrate were dissolved in 150 mL of methanol at a molar ratio of 1:4 to obtain solution A and solution B. Solution A was then poured into solution B and mixed and stirred for 5 min, followed by standing for 24 h. The resulting white solid product was centrifuged and washed three times with methanol, dried and dehydrated to obtain zeolite imidazole framework-8.

[0065] 2) Under magnetic stirring, 0.008 g of ferric nitrate nonahydrate and 0.065 g of p-phenylenediamine were mixed and dissolved in 10 mL of methanol at a molar ratio of 1:3 and stirred for 3 h. Then, 0.2 g of zeolite imidazole framework-8 was added and stirred for 1 h. The mixture was dried and dehydrated to obtain the iron atom catalyst precursor.

[0066] 3) The iron atom catalyst precursor was placed in a quartz boat and then transferred to a tube furnace. Nitrogen gas was introduced into the tube furnace to purge the air. Then, under a nitrogen atmosphere, the temperature was increased to 900℃ at a heating rate of 5℃ / min and held for 2h for pyrolysis. After cooling to room temperature, the pyrolysis product was acid-leached in 1mol / L H2SO4 for 2h, dried and dehydrated, and finally the iron atom catalyst FeNC-D-0.02-900 with moderate interatomic spacing was obtained.

[0067] Example 2

[0068] The preparation method in this embodiment is the same as in Example 1, except that ferric nitrate nonahydrate is not added to obtain NC-D.

[0069] Example 3

[0070] The preparation method in this embodiment is the same as in Example 1, except that ferric nitrate nonahydrate and p-phenylenediamine are not added to obtain NC.

[0071] Example 4

[0072] The preparation method in this embodiment is the same as in Example 1, except that the amount of ferric nitrate nonahydrate is 0.01 mmol (0.004 g) and the amount of o-phenylenediamine is 0.03 mmol (0.033 g), thus obtaining FeNC-D-0.01-900.

[0073] Example 5

[0074] The preparation method in this embodiment is the same as in Example 1, except that the amount of ferric nitrate nonahydrate is 0.03 mmol (0.012 g) and the amount of o-phenylenediamine is 0.09 mmol (0.099 g), thus obtaining FeNC-D-0.03-900.

[0075] Experimental Example 1

[0076] The removal rates of tetracycline (TC) in water by the products of Examples 1-5 were tested using the following methods:

[0077] A 250 mL conical flask was used as the reaction flask. 100 mL of simulated organic wastewater with an initial TC concentration of 10 mg / L was prepared without adjusting the wastewater pH (the wastewater pH was 6.3 at this time). 0.05 g / L of the catalyst prepared in Examples 1 to 5 and 1 mmol / L of PMS were added to the reaction flask, respectively. The mixture was stirred thoroughly in a constant temperature shaking shaker at 180 r / min at 25 °C. The residual TC concentration was measured at 1 min, 3 min, 5 min, 7 min, 10 min, 15 min, and 20 min, respectively, and the TC removal rate was calculated.

[0078] The calculation results are as follows Figure 1 As shown. By Figure 1 It can be seen that NC and NC-D alone have low TC removal rates, but the removal rate is significantly improved after the addition of Fe, reaching over 90% after 20 minutes of reaction. Furthermore, the TC removal rate initially increases and then decreases with increasing iron content.

[0079] Example 6

[0080] The preparation method in this embodiment is the same as in embodiment 1, except that the temperature of the tube furnace is raised to 800°C to obtain FeNC-D-0.2-800.

[0081] Example 7

[0082] The preparation method in this embodiment is the same as in Example 1, except that the temperature of the tube furnace is raised to 1000℃ to obtain FeNC-D-0.2-1000.

[0083] Experimental Example 2

[0084] The removal rate of TC in water by the products of Examples 1 and 6-7 was tested using the following methods:

[0085] A 250 mL conical flask was used as the reaction flask. 100 mL of simulated organic wastewater with an initial TC concentration of 10 mg / L was prepared without adjusting the wastewater pH (the wastewater pH was 6.3 at this time). 0.05 g / L of the catalyst prepared in Example 1 and Examples 6-7 and 1 mmol / L of PMS were added to the reaction flask, respectively. The mixture was stirred thoroughly in a constant temperature shaking shaker at 180 r / min at 25 °C. The residual TC concentration was measured at 1 min, 3 min, 5 min, 7 min, 10 min, 15 min, and 20 min, and the TC removal rate was calculated.

[0086] The calculation results are as follows Figure 2As shown. By Figure 2 It can be seen that the removal rate of TC increases significantly with increasing pyrolysis temperature, reaching over 90% at 900℃. However, the degradation efficiency does not improve significantly when the pyrolysis temperature is further increased to 1000℃.

[0087] Example 8

[0088] The preparation method in this embodiment is the same as in Example 1, except that the aniline ligand used is o-phenylenediamine, and FeNC-L-0.2-900 is obtained.

[0089] Example 9

[0090] The preparation method in this embodiment is the same as in Example 1, except that the aniline ligand used is diphenylamine, and FeNC-R-0.2-900 is obtained.

[0091] Experimental Example 3

[0092] The removal rate of TC in water by the products of Examples 1 and 8-9 was tested using the following methods:

[0093] A 250 mL conical flask was used as the reaction flask. 100 mL of simulated organic wastewater with an initial TC concentration of 10 mg / L was prepared without adjusting the wastewater pH (the wastewater pH was 6.3 at this time). 0.05 g / L of the catalyst prepared in Example 1 and Examples 8-9 and 1 mmol / L of PMS were added to the reaction flask. The mixture was stirred thoroughly in a constant temperature shaking shaker at 180 r / min at 25 °C. The residual TC concentration was measured at 1 min, 3 min, 5 min, 7 min, 10 min, 15 min, and 20 min, and the TC removal rate was calculated.

[0094] The calculation results are as follows Figure 3 As shown. By Figure 3 It can be seen that the removal rate of TC increases with the increase of the interatomic spacing of iron atoms, reaching a maximum removal rate of over 90% when the interatomic spacing is moderate. As the spacing further increases, the TC degradation efficiency decreases.

[0095] Figures 4-6 The images show transmission electron microscopy (TEM) images of the iron atom catalysts prepared in Examples 1 and 8-9. As shown in the figures, the catalysts all exhibit a plate-like structure with no obvious iron nanoparticles. X-ray diffraction patterns of the iron atom catalysts prepared in Examples 1 and 8-9 are shown below. Figure 7 As shown in the figure, the catalyst exhibits distinct characteristic peaks at 25° and 44°, corresponding to the (002) and (101) crystal planes of carbon, respectively, with no related peaks appearing for iron-based species. Figures 8-10These are aberration-corrected high-angle annular dark-field scanning transmission electron microscope images of the iron atom catalysts prepared in Examples 1 and 8-9, where... Figure 8 It can be seen that in the catalyst FeNC-L-0.2-900 prepared in Example 8, the iron atoms are distributed in pairs at closer distances on the carbon substrate surface, without obvious clusters; Figure 9 It can be seen that the iron atoms in the catalyst FeNC-D-0.2-900 prepared in Example 1 are distributed in pairs at medium distances on the surface of the carbon substrate, without obvious clusters; Figure 10 It can be seen that the iron atoms in the catalyst FeNC-R-0.2-900 prepared in Example 9 are independently and uniformly distributed on the surface of the carbon substrate, with a large distance between them and no obvious clusters. Figure 11 The images show the adsorption and desorption isotherms of the iron atom catalysts prepared in Examples 1 and 8-9. It can be seen that the prepared catalysts have a large specific surface area.

[0096] Example 10

[0097] This embodiment provides an iron atom catalyst with adjustable interatomic spacing, and the preparation steps are as follows:

[0098] 1) Under magnetic stirring, 5.95 g of 2-methylimidazole and 6.57 g of zinc nitrate hexahydrate were dissolved in 150 mL of methanol at a molar ratio of 1:4 to obtain solution A and solution B. Solution A was then poured into solution B and mixed and stirred for 10 min, followed by standing for 12 h. The resulting white solid product was centrifuged and washed three times with methanol, dried and dehydrated to obtain zeolite imidazole framework-8.

[0099] 2) Under magnetic stirring, 0.008 g of ferric nitrate nonahydrate and 0.065 g of p-phenylenediamine were mixed and dissolved in 10 mL of methanol at a molar ratio of 1:3 and stirred for 2 h. Then, 0.2 g of zeolite imidazole framework-8 was added and stirred for 2 h. The mixture was dried and dehydrated to obtain the iron atom catalyst precursor.

[0100] 3) The iron atom catalyst precursor was placed in a quartz boat and then transferred to a tube furnace. Nitrogen gas was introduced into the tube furnace to purge the air. Then, under a nitrogen atmosphere, the temperature was increased to 900℃ at a heating rate of 10℃ / min and held for 3h for pyrolysis. After cooling to room temperature, the pyrolysis product was acid-leached in 0.5mol / L H2SO4 for 3h, dried and dehydrated, and finally the iron atom catalyst FeNC-D-0.02-900 with moderate interatomic spacing was obtained.

[0101] In this embodiment, the TC removal rate reaches over 90%.

[0102] Experiment Example 4

[0103] Four treatment groups were set up using the iron atom catalyst prepared in Example 1: 250 mL conical flasks were used as reaction flasks, and 100 mL of simulated organic wastewater with an initial TC concentration of 10 mg / L was prepared. The pH of the wastewater was not adjusted (the pH of the wastewater at this time was 6.3). 0.025 g / L of catalyst (treatment group 1), 0.05 g / L (treatment group 2), 0.1 g / L (treatment group 3), 0.2 g / L (treatment group 4) and 1 mmol / L of PMS were added to the four reaction systems, respectively. The reaction was carried out by stirring thoroughly in a constant temperature shaking shaker at 180 r / min at 25-30 °C. The residual concentration of TC was measured at 1 min, 3 min, 5 min, 7 min, 10 min, 15 min, and 20 min, and the TC removal rate was calculated.

[0104] The calculation results are as follows Figure 12 As shown. By Figure 12 It can be seen that as the catalyst dosage increases from 0.025 g / L to 0.05 g / L, the DOX removal rate significantly improves, reaching a maximum removal rate of over 90% at 0.05 g / L. This indicates that with increasing catalyst dosage, the catalyst can provide more active sites and generate a large number of active species during the reaction, thereby improving the TC removal rate. When the catalyst dosage is further increased to 0.2 g / L, the TC removal rate only increases slightly, indicating that the active sites provided by the catalyst are excessive and cannot be fully utilized during the reaction. The above analysis results show that in practical applications, the catalyst dosage can be adjusted according to the actual conditions of local wastewater and the required treatment efficiency to achieve the goal of efficiently removing organic pollutants.

[0105] Experimental Example 5

[0106] Four treatment groups were set up using the iron atom catalyst prepared in Example 1: 250 mL conical flasks were used as reaction flasks, and 100 mL of simulated organic wastewater with an initial TC concentration of 10 mg / L was prepared. The pH of the wastewater was not adjusted (the pH of the wastewater at this time was 6.3). PMS 0.5 mmol / L (treatment group 1), 1.0 mmol / L (treatment group 2), 2.0 mmol / L (treatment group 3), 3.0 mmol / L (treatment group 4) and 0.3 g / L of catalyst were added to the four reaction systems, respectively. The reaction was carried out by stirring thoroughly in a constant temperature shaking shaker at 180 r / min at 25-30 °C. The residual concentration of TC was measured at 1 min, 3 min, 5 min, 7 min, 10 min, 15 min and 20 min, respectively, and the TC removal rate was calculated.

[0107] The calculation results are as follows Figure 13 As shown. By Figure 13It can be seen that as the PMS concentration increases, the TC removal rate continuously improves and can reach a high level. This indicates that in practical applications, the PMS concentration can be adjusted according to the actual situation of local wastewater and the needs of treatment efficiency in order to control costs and improve removal efficiency.

[0108] Experimental Example 6

[0109] Seven treatment groups were set up using the iron atom catalyst prepared in Example 1: 250 mL conical flasks were used as reaction flasks, and 100 mL of simulated organic wastewater with an initial TC concentration of 10 mg / L was prepared. The initial pH of the wastewater was adjusted to: 1 (treatment group 1), 3 (treatment group 2), 5 (treatment group 3), 7 (treatment group 4), 9 (treatment group 5), 11 (treatment group 6), and 13 (treatment group 7), respectively. 0.05 g / L of catalyst and 1 mmol / L of PMS were added to the reaction flasks, respectively. The reaction was carried out by stirring thoroughly in a constant temperature shaking shaker at 180 r / min at 25-30 °C. The residual TC concentration was measured at 1 min, 3 min, 5 min, 7 min, 10 min, 15 min, and 20 min, respectively, and the TC removal rate was calculated.

[0110] The calculation results are as follows Figure 14 As shown. By Figure 14 It can be seen that, except for pH values ​​of 1 and 13, the TC removal rate reached over 90% under other pH conditions, indicating that in practical applications, the system has strong adaptability to the pH values ​​of wastewater under different environments and can efficiently treat antibiotics in various types of wastewater.

[0111] Experimental Example 7

[0112] Four treatment groups were set up using the iron atom catalysts prepared in Examples 1 and 8-9 respectively: 250mL conical flasks were used as reaction flasks, and 100mL of simulated organic wastewater containing different pollutants with an initial concentration of 10mg / L were prepared respectively: bisphenol A (BPA, treatment group 1), TC (treatment group 2), sulfamethoxazole (SMX, treatment group 3), and benzoic acid (BA, treatment group 4). The pH of the wastewater was not adjusted (the pH of the wastewater at this time was 6.3). 0.05g / L of catalyst and 1mmol / L of PMS were added to the reaction flasks respectively, and the reaction was carried out by stirring thoroughly in a constant temperature shaking shaker at 180r / min at 25-30℃. The residual concentration of TC was measured at 1min, 3min, 5min, 7min, 10min, 15min, and 20min respectively, and the removal rate of TC was calculated.

[0113] The calculation results are as follows Figures 15-17 As shown, the degradation of different pollutants in the three systems exhibited significant differences. Figure 15It can be seen that the catalyst prepared in Example 1 can achieve a removal rate of over 80% for low-ionization potential pollutants (BPA, TC, SMX) within 20 min, while it is difficult to effectively degrade high-ionization potential pollutants (BA). This indicates that the oxidation pathway of pollutants in this system is a non-radical pathway that can selectively degrade low-ionization potential pollutants. Figure 16 It can be seen that the catalyst prepared in Example 8 can achieve a removal rate of over 90% for low-ionization potential pollutants (BPA, TC, SMX) within 20 min, while it is difficult to effectively degrade high-ionization potential pollutants (BA). This indicates that the oxidation pathway of pollutants in this system is a non-radical pathway that can selectively degrade low-ionization potential pollutants. Figure 17 It can be seen that the catalyst prepared in Example 9 can achieve a removal rate of more than 60% for pollutants with low ionization potential (BPA, TC, SMX) within 20 min, while the removal rate for pollutants with high ionization potential (BA) is only about 30%. This indicates that the oxidation pathway of pollutants in this system is mainly the non-radical pathway that can selectively degrade pollutants with low ionization potential, and the free radical pathway also makes a slight contribution.

[0114] Experimental Example 8

[0115] The cyclic stability of the iron atom catalysts prepared in Examples 1 and 8-9 was tested: A 250 mL Erlenmeyer flask was used as the reaction flask. 100 mL of simulated organic wastewater with an initial TC concentration of 10 mg / L was prepared without adjusting the wastewater pH (the pH of the wastewater at this time was 6.3). 0.05 g / L of catalyst and 1 mmol / L of PMS were added to the reaction system. The reaction was carried out by stirring thoroughly in a constant temperature shaking shaker at 180 r / min at 25-30 °C. The residual TC concentration was measured at 1 min, 3 min, 5 min, 7 min, 10 min, 15 min, and 20 min, and the TC removal rate was calculated. After the reaction was completed, the degraded catalyst was collected by vacuum filtration, washed with deionized water, filtered and dried, and then subjected to a cyclic experiment according to the above test method.

[0116] Test results are as follows Figures 18-20 As shown. By Figure 18 It can be seen that after five cycles, the degradation rate of TC by the catalyst prepared in Example 8 decreased by 27.4%, but recovered to 85.6% after recalcination at 350°C, indicating that the active sites have strong regenerative capacity; Figure 19 It can be seen that the catalyst prepared in Example 1 showed a 12.3% decrease in TC degradation rate, which recovered to 90.4% after recalcination at 350℃, indicating stronger regenerability of the active sites; Figure 20It can be seen that the degradation rate of TC by the catalyst prepared in Example 9 decreased by 27.7%, but recovered to 57.5% after reheating at 350°C, indicating that the active sites are not easily regenerated.

[0117] Experimental Example 9

[0118] Quenching experiments were conducted using the iron atom catalysts prepared in Examples 1 and 8-9, with four treated groups and one untreated group. A 250 mL Erlenmeyer flask was used as the reaction vessel. 100 mL of simulated organic wastewater with an initial TC concentration of 10 mg / L was prepared, without adjusting the wastewater pH (which was 6.0 at this point). 0.05 g / L of catalyst and 1 mmol / L of PMS were added to the reaction vessel, followed by the addition of 1000 mmol / L of ethanol (EtOH) as quenchers for sulfate radicals and hydroxyl radicals (treatment group 1). 50 mmol / L tert-butanol (TBA) was used as a quencher for hydroxyl radicals (treatment group 2), 50 mmol / L furfuryl alcohol (FFA) was used as a quencher for singlet oxygen (treatment group 3), and 50 mmol / L methyl phenyl sulfoxide (PMSO) was used as a quencher for high-valent iron species (treatment group 4). The reaction was carried out by stirring thoroughly in a constant temperature shaking shaker at 180 r / min. The residual concentration of TC was measured at 1 min, 3 min, 5 min, 7 min, 10 min, 15 min, and 20 min, and the TC removal rate was calculated.

[0119] The calculation results are as follows Figures 21-23 As shown. By Figure 21 It can be seen that in the catalyst system prepared in Example 1, the inhibitory effect of adding ethanol and tert-butanol on TC removal is negligible, indicating that SO42- ·- and · OH plays a relatively minor role in the reaction; the addition of furfuryl alcohol only inhibited TC removal by 8.34%, indicating that... 1 O2 plays a relatively minor role in the reaction; the addition of methyl phenyl sulfoxide inhibited TC removal by 72.31%, indicating that the non-radical pathway, primarily HV-Me, plays the most significant role in TC removal. Figure 22 It can be seen that in the catalyst system prepared in Example 8, the inhibitory effect of adding ethanol and tert-butanol on TC removal is negligible, indicating that SO42- ·- and · OH plays a relatively minor role in the reaction; the addition of furfuryl alcohol and methyl phenyl sulfoxide inhibited TC removal by 27.06% and 53.42%, respectively, indicating that HV-Me was the dominant molecule. 1 The non-radical pathway, with O2 as a secondary component, plays a major role in TC removal. Figure 23It can be seen that in the catalyst system prepared in Example 9, the inhibition rates of TC removal after the addition of ethanol and tert-butanol were 20.21% and 17.21%, respectively, indicating that... · OH plays a weak role in the reaction, SO4 ·- The role played by these substances in the reaction process is negligible; the addition of furfuryl alcohol and methyl phenyl sulfoxide inhibited TC removal by 43.83% and 13.36%, respectively, indicating that... 1 The non-radical pathway, primarily O2-based and secondarily HV-Me-based, plays the most significant role in TC removal. Additionally, [the pathway is further elaborated upon by other factors]. · The OH-based free radical pathway also made a slight contribution. The non-free radical pathway is less affected by changes in external conditions and can treat antibiotic contaminants in complex water conditions under various circumstances.

[0120] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. The use of an atomic distance adjustable iron atomic catalyst in the removal of antibiotics or bisphenol A in activated PMS wastewater, characterized in that, The preparation method of the iron atomic catalyst comprises the following steps: 1) mixing and dissolving ferric nitrate nonahydrate and aniline ligand, then adding zeolitic imidazolate framework-8 after mixing, and then drying and dehydrating to obtain an iron atomic catalyst precursor; 2) sequentially subjecting the iron atomic catalyst precursor to pyrolysis, acid washing, drying and dehydration to obtain an iron atomic catalyst; The preparation method of the zeolitic imidazolate framework-8 in the step 1) is as follows: 2-methyl imidazole and zinc nitrate hexahydrate are respectively dissolved in methanol, then the two solutions are mixed and sequentially subjected to standing, centrifugation, washing, drying and dehydration to obtain the zeolitic imidazolate framework-8; The aniline ligand in the step 1) is o-phenylenediamine or p-phenylenediamine. In the pyrolysis step in the step 2), nitrogen is used as the protective gas, the heating rate is 5-10 ℃ / min, the pyrolysis temperature is 800-1000 ℃, and the pyrolysis holding time is 2-3 h.

2. Use according to claim 1, characterized in that, The molar ratio of the 2-methyl imidazole to the zinc nitrate hexahydrate is 1:

4.

3. Use according to claim 1, characterized in that, The molar ratio of the ferric nitrate nonahydrate to the aniline ligand in the step 1) is 1:

3.

4. Use according to claim 1, characterized in that, The mixing time of the ferric nitrate nonahydrate and the aniline ligand in the step 1) is 2-3 h, and the mixing time of the mixed solution and the zeolitic imidazolate framework-8 is 1-2 h.

5. The use according to claim 1, characterized in that, In the step 2), the acid washing solution used is a 0.5-1 mol / L H2SO4 solution, and the acid washing time is 2-3 h.

6. Use according to claim 1, characterized in that, The antibiotics include tetracycline and sulfamethoxazole.

7. Use according to claim 6, characterized in that, The dosage of the catalyst is 0.025 g / L-0.2 g / L, and the concentration of the PMS is 0.5 mmol / L-3 mmol / L.

8. Use according to claim 6, characterized in that, When the antibiotics or bisphenol A in the wastewater is removed, the pH value of the reaction system is 1-13, and the temperature of the reaction system is 25-30 ℃.

Images