MOF@COF / BC-based electrode material and application thereof in wastewater treatment
By in-situ growing Mel-MoPc on MIL101(Fe) and loading it onto biochar, MOF@COF/BC electrode material was prepared, which solved the problems of poor conductivity and poor crystallinity of existing electrode materials, and achieved efficient degradation of ofloxacin wastewater redox reaction, improving catalytic activity and stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHANDONG AGRICULTURAL UNIVERSITY
- Filing Date
- 2025-01-16
- Publication Date
- 2026-06-26
AI Technical Summary
In existing electrochemical activation persulfate technology, the choice of electrode material affects the activation efficiency of persulfate. Current electrode materials suffer from poor conductivity and poor crystallinity, resulting in low degradation efficiency of antibiotic wastewater.
Using MOF@COF/BC electrode material, a COF structure was formed by in-situ growth of Mel-MoPc on MIL101(Fe) and then loaded onto biochar, thus preparing an electrode material with superior electrochemical performance and high catalytic activity. This material was then used to activate persulfate to degrade ofloxacin in an electrochemical system.
The degradation efficiency of ofloxacin wastewater was improved, the catalytic activity and stability of the electrode material were significantly enhanced, and more active oxide species were generated by activating persulfate, thus achieving efficient degradation of ofloxacin.
Smart Images
Figure CN119873966B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of wastewater treatment technology, specifically to an electrode material based on MOF@COF / BC and its application in wastewater treatment. Background Technology
[0002] Ofloxacin (OFX) is a common quinolone antibiotic widely used in medical, livestock, and aquaculture industries. Its stable structure and long degradation time in the environment allow it to persist for extended periods with high bioactivity. Most OFX is non-biodegradable and is frequently detected in wastewater, surface water, and even drinking water. Excessive OFX residues in water can cause a range of problems, including antibiotic-resistant bacteria and chronic toxicity, and can accumulate in the human body through the food chain, posing threats to ecosystems and human health. Therefore, effective methods for degrading residual OFX in water bodies are urgently needed.
[0003] Currently, the main methods for degrading antibiotic-containing wastewater include photocatalysis, ozone catalysis, Fenton catalysis, and advanced oxidation technologies such as activated persulfate. Among them, activated persulfate has the advantages of strong oxidizing power, fast reaction, and low energy consumption, and is currently the main method used for degrading antibiotic wastewater.
[0004] Advanced oxidation technologies based on persulfate utilize the activation of persulfate to generate a large amount of active substances, which then undergo a series of redox reactions with recalcitrant organic pollutants in water, thereby degrading these pollutants. Common methods for activating persulfate include thermal activation, ultrasonic activation, photoactivation, transition metal and oxide activation, and electrochemical activation. Among these, electrochemical activation of persulfate involves the persulfate gaining electrons at the cathode. Using a stable anode, the O / O bonds of the persulfate break under the bombardment of electrons provided by the cathode, generating sulfate radicals with high redox potentials. The key to electrochemical activation of persulfate lies in the selection of electrode materials. Electrode materials are the core of the electrochemical system, closely related to the electron transfer rate of the reaction system, and thus affecting the activation efficiency of persulfate. Therefore, developing new electrode materials for activating persulfate remains a current research hotspot and challenge. Summary of the Invention
[0005] To address the aforementioned limitations of existing technologies, the present invention aims to provide an electrode material based on MOF@COF / BC and its application in wastewater treatment. This invention develops and designs a novel electrode material for the electrocatalytic activation of persulfate (PMS) degradation of OFX wastewater, significantly improving the degradation efficiency of OFX wastewater.
[0006] To achieve the above objectives, the present invention adopts the following technical solution:
[0007] In a first aspect, the present invention provides an electrode material based on MOF@COF / BC, which is prepared by the following method:
[0008] (1) NH2-MIL101(Fe), melamine and molybdenum phthalocyanine were dissolved in dimethyl sulfoxide (DMSO) and reacted at 160-200℃ for 10-14h. After the reaction, the precipitate was collected, washed and dried to prepare NH2-MIL101(Fe)@Mel-MoPc.
[0009] (2) Biochar (BC) and NH2-MIL101(Fe)@Mel-MoPc were mixed in deionized water, ultrasonically treated for 8-12 min, stirred for 10-14 h, and then the precipitate was collected by centrifugation, washed and dried to prepare electrode material (MIL101(Fe)@Mel-MoPc / BC).
[0010] Preferably, in step (1), the mass ratio of NH2-MIL101(Fe), melamine and molybdenum phthalocyanine added is (0.33-1.5):(0.165-0.33):(0.335-0.67).
[0011] More preferably, the mass ratio of NH2-MIL101(Fe), melamine and molybdenum phthalocyanine added is 0.5:0.33:0.67.
[0012] Preferably, in step (2), the biochar is prepared by the following method:
[0013] Rice husks were placed in a tube furnace and heated to 500°C at a rate of 5°C / min under a nitrogen atmosphere, and held for 2 hours.
[0014] Preferably, in step (2), the mass ratio of biochar to NH2-MIL101(Fe)@Mel-MoPc is 2:1.
[0015] This invention utilizes melamine and molybdenum phthalocyanine to grow in situ on MIL101(Fe) to form Mel-MoPc with a COF structure, thus obtaining MOF@COF material. The MOF@COF material is then loaded onto biochar (BC) to prepare an electrode material based on MOF@COF / BC. The electrode material prepared by this invention exhibits superior electrochemical performance, high catalytic activity, and a more stable structure.
[0016] A second aspect of the present invention provides the application of the above-described electrode material in (1) or (2) as follows:
[0017] (1) Activate persulfate;
[0018] (2) Degradation of antibiotics.
[0019] In the above applications, the preferred antibiotic is ofloxacin.
[0020] A third aspect of the present invention provides an electrochemical system for degrading ofloxacin, comprising: an anode, a cathode, and an electrolyte;
[0021] The anode is a graphite electrode;
[0022] The cathode is prepared by the following method:
[0023] The above electrode material is mixed with carbon black, and then polyvinylidene fluoride (PVDF) and N-methylpyrrolidone (NMP) are added and ground into a paste. The paste is then coated on both sides of graphite paper to prepare a cathode.
[0024] The electrolyte is 50 mM Na2SO4.
[0025] Preferably, the electrode material and carbon black are mixed at a mass ratio of 2:1.
[0026] A fourth aspect of the present invention provides a method for degrading ofloxacin in wastewater using the above-described electrochemical system, comprising the following steps:
[0027] The cathode and anode are installed in an electrolytic cell containing electrolyte. Wastewater to be treated is added to the electrolytic cell, and PMS is added to adjust the pH of the system to 7. The current is controlled at 300-900mA to degrade ofloxacin in the wastewater.
[0028] Preferably, PMS is added to achieve a final concentration of 0.5 mM.
[0029] The beneficial effects of this invention are:
[0030] This invention is the first to prepare an electrode material based on MOF@COF / BC, wherein:
[0031] MIL101(Fe) possesses a large cell volume, large specific surface area, high porosity, excellent thermal stability, and numerous unsaturated active sites. Its active Fe(II) / Fe(III) valence state transformation and excellent ligand-metal electron transfer capabilities during catalysis are beneficial for activating PMS. Melamine, as a monomer in COF, contains a rigid triazine ring with three functional amino groups, providing more active sites. Phthalocyanine in molybdenum phthalocyanine has a broad 18-electron conjugation system, offering significant advantages as a catalyst active center in COF. By molybdenizing its central cavity, molybdenum phthalocyanine with a Mo-N4 structure can be formed, serving as a highly efficient active site for activating PMS. Biochar, with its porous structure, abundant functional groups, and large specific surface area, can serve as a catalyst support, providing numerous active functional groups (such as C=O) for reactions promoting reactive oxygen species formation. (C=O + S2O8)2 -→CO + +SO4 2- +SO4 .- C = O + S2O8 2 -→CO + +SO4 2- +O2 .- ).
[0032] However, MIL101(Fe) alone has poor electrical conductivity, while Mel-MoPc suffers from poor crystallinity. This invention addresses this by in-situ growing Mel-MoPc on MIL101(Fe), assembling the two into a single system to form a MIL101(Fe)@Mel-MoPc composite material with superior electrochemical performance, higher catalytic activity, and a more stable structure. This composite provides more active sites and channels, facilitating charge transport. Furthermore, loading this composite onto BC provides the structural advantage of supporting MIL101(Fe)@Mel-MoPc, exposing more active sites and improving catalytic performance. In addition, the presence of oxygen-containing functional groups in BC allows PMS to generate free radicals directly or indirectly through electron transfer, further enhancing the catalyst's activation performance for PMS. Attached Figure Description
[0033] Figure 1 SEM images of different materials, including: (a) BC, (b) NH2-MIL101(Fe), (c) Mel-MoPc, (d) NH2-MIL101(Fe)@Mel-MoPc, and (e) MIL101(Fe)@Mel-MoPc / BC.
[0034] Figure 2 XPS spectra of MIL101(Fe)@Mel-MoPc / BC prepared in Example 1, wherein (a) is the fine spectrum of C1s, (b) is the N1s spectrum, (c) is the Fe 2p spectrum, and (d) is the fine spectrum of Mo 3d.
[0035] Figure 3CV diagrams of different electrode materials; where, in (a), 1:2 represents MIL101(Fe)@Mel-MoPc / BC prepared in Example 1, 1:1 represents MIL101(Fe)@Mel-MoPc / BC prepared in Example 2, 1:3 represents MIL101(Fe)@Mel-MoPc / BC prepared in Example 3, 2:1 represents MIL101(Fe)@Mel-MoPc / BC prepared in Example 4, and 3:1 represents MIL101(Fe)@Mel-MoPc / BC prepared in Example 5; in (b), 1:2 represents MIL101(Fe)@Mel-MoPc / BC prepared in Example 1 The prepared MIL101(Fe)@Mel-MoPc / BC are as follows: 1:1 represents MIL101(Fe)@Mel-MoPc / BC prepared in Example 6; 1:3 represents MIL101(Fe)@Mel-MoPc / BC prepared in Example 7; 2:1 represents MIL101(Fe)@Mel-MoPc / BC prepared in Example 8; 3:1 represents MIL101(Fe)@Mel-MoPc / BC prepared in Example 9; 1:0 represents NH2-MIL101(Fe)@Mel-MoPc alone; and 0:1 represents BC alone.
[0036] Figure 4 IT diagrams of different electrode materials; where, in (a), 1:2 represents MIL101(Fe)@Mel-MoPc / BC prepared in Example 1, 1:1 represents MIL101(Fe)@Mel-MoPc / BC prepared in Example 2, 1:3 represents MIL101(Fe)@Mel-MoPc / BC prepared in Example 3, 2:1 represents MIL101(Fe)@Mel-MoPc / BC prepared in Example 4, and 3:1 represents MIL101(Fe)@Mel-MoPc / BC prepared in Example 5; in (b), 1:2 represents MIL101(Fe)@Mel-MoPc / BC prepared in Example 1 The prepared MIL101(Fe)@Mel-MoPc / BC are as follows: 1:1 represents MIL101(Fe)@Mel-MoPc / BC prepared in Example 6; 1:3 represents MIL101(Fe)@Mel-MoPc / BC prepared in Example 7; 2:1 represents MIL101(Fe)@Mel-MoPc / BC prepared in Example 8; 3:1 represents MIL101(Fe)@Mel-MoPc / BC prepared in Example 9; 1:0 represents NH2-MIL101(Fe)@Mel-MoPc alone; and 0:1 represents BC alone.
[0037] Figure 5 Active species were detected in the electrocatalytically activated PMS degradation OFX system by electron paramagnetic resonance (EPR).
[0038] Figure 6The effect of different current conditions on the degradation of OFX.
[0039] Figure 7 Results of the cyclic stability study of the electrode material.
[0040] Figure 8 The degradation effect of different electrode materials on OFX. Detailed Implementation
[0041] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.
[0042] To enable those skilled in the art to better understand the technical solution of this application, the technical solution of this application will be described in detail below with reference to specific embodiments.
[0043] The test materials used in the embodiments and comparative examples of this invention, unless otherwise specified, are all conventional test materials in the art and can be purchased commercially. Among them:
[0044] NH2-MIL101(Fe) is prepared by the following method:
[0045] 0.412 g of 2-aminoterephthalic acid and 1.35 g of ferric chloride hexahydrate were added to 30 mL of N,N-dimethylamide (DMF) solution and stirred until homogeneous. The mixture was then poured into a reaction vessel and reacted at 110 °C for 20 hours. After cooling to room temperature, the mixture was centrifuged at 4500 rpm for 2 min to obtain NH2-MIL101(Fe). The Fe was washed with DMF solution and ethanol, dried under vacuum at 60 °C, and ground for later use.
[0046] Molybdenum phthalocyanine is prepared by the following method:
[0047] 3.8 g of 4-nitrophthalonitrile, 9.6 g of molybdenum chloride, and 9.6 g of urea were ground together and reacted at 160 °C for 5 h with 150 mg of ammonium molybdate as a catalyst. Unreacted substances were removed by washing with 100 mL of 1 M hydrochloric acid at 90 °C, and further washed with 100 mL of 1 M NaOH solution until the pH was neutral. After washing with water, filtration, and vacuum drying, molybdenum phthalocyanine was prepared.
[0048] Biochar (BC) is prepared by the following method:
[0049] Rice husk biomass was placed in a tube furnace and heated to 500℃ at a rate of 5℃ / min under a nitrogen atmosphere, and held for 2 hours. The reaction product was ground through a 100-mesh sieve and soaked in a 1mol / L hydrochloric acid solution (solid-liquid ratio 1g:100mL) for 24 hours to remove ash and other impurities. It was then washed with deionized water until neutral and dried at 105℃ to prepare biochar.
[0050] Example 1: Fabrication of electrode materials based on MOF@COF / BC
[0051] 1. Preparation of NH2-MIL101(Fe)@Mel-MoPc:
[0052] 0.5 g NH2-MIL101(Fe), 0.33 g melamine, and 0.67 g molybdenum phthalocyanine were dissolved in a reactor containing 23 mL DMSO to obtain a clear solution. The solution was reacted at 180 °C for 12 hours. After the reactor cooled to room temperature, the white precipitate was collected and washed with excess dichloromethane, acetone, ethanol, and distilled water to remove unreacted precursor materials and possible residual solvents in the mixture. Finally, the solution was dried in an oven at 70 °C to prepare NH2-MIL101(Fe)@Mel-MoPc.
[0053] 2. Preparation of MIL101(Fe)@Mel-MoPc / BC:
[0054] NH2-MIL101(Fe)@Mel-MoPc and BC were mixed in deionized water at a mass ratio of 1:2, and the mixture was sonicated (ultrasonic power 500W) for 10 min and stirred for 12 h. The mixture was then centrifuged at 10000 rpm, the precipitate was collected, washed with ethanol, and dried at 60 °C for 24 h to obtain MIL101(Fe)@Mel-MoPc / BC.
[0055] Example 2:
[0056] The difference from Example 1 is that 1g of NH2-MIL101(Fe), 0.33g of melamine and 0.67g of molybdenum phthalocyanine were dissolved in a reactor containing 23mL of DMSO, and the remaining reaction conditions were the same as in Example 1, to prepare MIL101(Fe)@Mel-MoPc / BC.
[0057] Example 3:
[0058] The difference from Example 1 is that 0.33g NH2-MIL101(Fe), 0.33g melamine and 0.67g molybdenum phthalocyanine were dissolved in a reactor containing 23mL DMSO, and the remaining reaction conditions were the same as in Example 1, to prepare MIL101(Fe)@Mel-MoPc / BC.
[0059] Example 4:
[0060] The difference from Example 1 is that 1g of NH2-MIL101(Fe), 0.165g of melamine and 0.335g of molybdenum phthalocyanine were dissolved in a reactor containing 23mL of DMSO, and the remaining reaction conditions were the same as in Example 1, to prepare MIL101(Fe)@Mel-MoPc / BC.
[0061] Example 5:
[0062] The difference from Example 1 is that 1.5g of NH2-MIL101(Fe), 0.165g of melamine and 0.335g of molybdenum phthalocyanine were dissolved in a reactor containing 23mL of DMSO, and the remaining reaction conditions were the same as in Example 1, to prepare MIL101(Fe)@Mel-MoPc / BC.
[0063] Example 6:
[0064] The difference from Example 1 is that NH2-MIL101(Fe)@Mel-MoPc and BC were mixed in deionized water at a mass ratio of 1:1, and the remaining reaction conditions were the same as in Example 1 to prepare MIL101(Fe)@Mel-MoPc / BC.
[0065] Example 7:
[0066] The difference from Example 1 is that NH2-MIL101(Fe)@Mel-MoPc and BC were mixed in deionized water at a mass ratio of 1:3, and the remaining reaction conditions were the same as in Example 1 to prepare MIL101(Fe)@Mel-MoPc / BC.
[0067] Example 8:
[0068] The difference from Example 1 is that NH2-MIL101(Fe)@Mel-MoPc and BC are mixed in deionized water at a mass ratio of 2:1, and the remaining reaction conditions are the same as in Example 1 to prepare MIL101(Fe)@Mel-MoPc / BC.
[0069] Example 9:
[0070] The difference from Example 1 is that NH2-MIL101(Fe)@Mel-MoPc and BC were mixed in deionized water at a mass ratio of 3:1, and the remaining reaction conditions were the same as in Example 1 to prepare MIL101(Fe)@Mel-MoPc / BC.
[0071] Comparative Example 1:
[0072] 0.33 g of melamine and 0.67 g of molybdenum phthalocyanine were dissolved in a reactor containing 23 mL of DMSO to obtain a clear solution. The solution was reacted at 180 °C for 12 hours. After the reactor cooled to room temperature, a white precipitate was collected and washed with excess dichloromethane, acetone, ethanol, and distilled water to remove unreacted precursor materials and possible residual solvents. Finally, the precipitate was dried in an oven at 70 °C to prepare Mel-MoPc.
[0073] Comparative Example 2:
[0074] NH2-MIL101(Fe) and BC were mixed in deionized water at a mass ratio of 1:2, and the mixture was sonicated (ultrasonic power 500W) for 10 min and stirred for 12 h. The mixture was then centrifuged at 10000 rpm, the precipitate was collected, washed with ethanol, and dried at 60 °C for 24 h to obtain MIL101(Fe) / BC.
[0075] Comparative Example 3:
[0076] Mel-MoPc and BC prepared in Comparative Example 1 were mixed in deionized water at a mass ratio of 1:2, and ultrasonically treated (ultrasonic power 500W) for 10 min, followed by stirring for 12 h. The mixture was then centrifuged at 10000 rpm, the precipitate was collected, washed with ethanol, and dried at 60 °C for 24 h to obtain Mel-MoPc / BC.
[0077] Experimental Example 1:
[0078] Scanning electron microscopy analysis was performed on NH2-MIL101(Fe) and BC used in this invention, NH2-MIL101(Fe)@Mel-MoPc and MIL101(Fe)@Mel-MoPc / BC in Example 1, and Mel-MoPc prepared in Comparative Example 1.
[0079] Its SEM, such as Figure 1 As shown, by Figure 1 It can be seen that the surface of biochar BC is rough and has a rich pore structure. Figure 1 a); NH2-MIL101(Fe) exhibits a typical hexagonal microspindle morphology. Figure 1 b). Mel-MoPc exhibits surface-aggregated nanoparticles ( Figure 1 c). Figure 1 (d) shows the morphology of NH2-MIL101(Fe)@Mel-MoPc. It can be seen that Mel-MoPc nanoparticles are dispersed on the surface of NH2-MIL101(Fe), uniformly encapsulating NH2-MIL101(Fe). Figure 1e indicates that NH2-MIL101(Fe)@Mel-MoPc is loaded onto a rough BC surface, demonstrating the successful synthesis of MIL101(Fe)@Mel-MoPc / BC.
[0080] XPS analysis was performed on the MIL101(Fe)@Mel-MoPc / BC prepared in Example 1 of this invention, and the results are as follows: Figure 2 As shown. Figure 2 (a) shows the fine spectrum of C1s, where 287.6 eV, 286 eV, 285.2 eV, and 284.3 eV correspond to C=O, CC / CN, C=N, and CC, respectively, which can effectively promote the formation of reactive oxygen species during the reaction. The formation of the C=N imine covalent bond indicates that MOF@COF is effectively synthesized, making it more stable and beneficial to charge transport and catalytic performance. Figure 2 (b) The peak at 399.4 eV in the N 1s spectrum represents a Mo-N bond, indicating the presence of Mo-N4 and providing an active site for the reaction. This suggests that electron transfer occurs between the metal and the N atom. The peak at 400.1 eV is attributed to -NH2, while 400.6 eV and 711.7 eV correspond to graphite-N and pyrrole-N, respectively. Electro-activated pyrrole-N can provide abundant active sites, generating more active species. Fe 2p... Figure 2 As shown in (c), 724.6 eV and 711.7 eV correspond to Fe 3+ 2p 3 / 2 and 2p 1 / 2 Fe 2+ The characteristic peaks are located at 717.5 eV and 709.4 eV, indicating the presence of Fe. 2+ / Fe 3+ The redox cycle promotes PMS activation. The peak at 714.4 eV corresponds to Fe-N, providing a superior active site and enhancing catalytic performance. The peak at 533.4 eV corresponds to the Fe-O bond, while the peaks at 532.8 eV and 535.1 eV belong to the Mo=O bond and -OH, respectively. The fine spectrum of Mo 3d is shown below. Figure 2 (d) shows that the peaks at 229.7 eV and 225.1 eV correspond to the Mo-C bond and the Mo bond, respectively. 3+ The two peaks at 231.8 eV and 227.6 eV belong to Mo. 4+ Mo 3d 3 / 2 and Mo 3d 5 / 2 The bond energies. The two peaks at 235.3 eV and 233.8 eV belong to Mo. 6+ 232.1 eV and 228.7 eV belong to Mo 5+ This indicates the presence of Mo. 3+ / Mo 4+ / Mo 5+ / Mo 6+ The redox cycle between Fe, Mo, C, and N promotes the generation of active species. XPS results further confirm the successful preparation of MIL101(Fe)@Mel-MoPc / BC. In addition, the formation of MNC structures among Fe, Mo, C, and N is more conducive to electron transfer, further enhancing the electrocatalytic performance of the material.
[0081] Experimental Example 2:
[0082] The redox ability and electron transfer ability of MIL101(Fe)@Mel-MoPc / BC prepared in Examples 1-9 of this invention were investigated, as follows:
[0083] 1. Cyclic Voltmeter-Cell (CV) Test:
[0084] Cyclic voltammetry (CV) results showed that the MIL101(Fe)@Mel-MoPc / BC prepared in Example 1 had the highest peak current. Figure 3 This indicates that the catalyst prepared under these conditions has a stronger redox capability.
[0085] 2. Timing Current Test (IT):
[0086] Chronoamperometry (IT) was performed under open-circuit voltage conditions with 50 mM Na₂SO₄ as the electrolyte. The sampling interval was 0.1 s, the run time was 300 s, and the sensitivity was 0.0001 A / V. 0.5 mM PMS was added at 100 s. Under open-circuit voltage conditions, the current increased immediately after the addition of 0.5 mM PMS at 100 s, demonstrating electron transfer between the material and PMS. A larger current change indicates a stronger electron transfer capability.
[0087] Depend on Figure 4 It can be seen that after adding PMS, the current change of the material prepared in Example 1 is 1.4028e. -7 The current change when using NH2-MIL101(Fe)@Mel-MoPc alone is 0.9022e -7 The current change when using BC alone is 0.487e -7 This demonstrates that the material prepared in Example 1 has the strongest electron transfer capability. Combining NH2-MIL101(Fe)@Mel-MoPc with BC has a synergistic effect on improving the electron transfer capability of the material.
[0088] Experimental Example 3:
[0089] The electrode material prepared in this invention is used to activate PMS to degrade OFX, as detailed below:
[0090] 1. Construction of the reaction system:
[0091] Electrode material and carbon black were mixed at a mass ratio of 2:1 (total mixture 10 mg), and then thoroughly ground with 10 mg of polyvinylidene fluoride (PVDF) in a quartz mortar. 0.3 mL of NMP was then added, and the mixture was thoroughly sonicated. The resulting paste was then drop-coated onto one side of graphite paper (2 cm × 2 cm × 1 mm) and allowed to air dry. The other side was treated similarly to prepare the cathode. This cathode, along with a graphite anode (2 cm × 2 cm × 1 mm), was placed in a 200 mL cylindrical electrolytic cell with a 2 cm gap between the electrodes. A reaction system was constructed using 50 mM Na₂SO₄ as the electrolyte.
[0092] 2. Investigation of active substances in the electrocatalytically activated PMS system for OFX degradation:
[0093] The electrode material MIL101(Fe)@Mel-MoPc / BC prepared in Example 1 was used to construct a reaction system according to the above method. PMS and OFX were added to the reaction system to make the final concentration of PMS 0.5mM and the concentration of OFX 10mg / L. The current was set to 300mA.
[0094] Electron paramagnetic resonance (EPR) detection revealed the presence of active species SO4 in the electrocatalytically activated PMS system for the degradation of OFX. - ·OH, ·O2 - and 1 O2; results as follows Figure 5 As shown, PMS was successfully activated to generate active species for the degradation and removal of OFX.
[0095] 3. Optimization of reaction conditions:
[0096] The electrode material MIL101(Fe)@Mel-MoPc / BC prepared in Example 1 was used to construct a reaction system according to the above method. PMS and OFX were added to the reaction system to make the final concentration of PMS 0.5 mM and the concentration of OFX 10 mg / L. The currents were set to 100 mA, 300 mA, 500 mA, 700 mA and 900 mA to investigate the effect of different current conditions on the degradation effect of OFX.
[0097] The results are as follows Figure 6 As shown, the degradation of OFX increases with increasing current; when the current is ≥300 mA, the degradation rate of OFX reaches over 92%. Specifically, when the current is set to 900 mA, the OFX degradation rate reaches as high as 99.12%. The increased current promotes the degradation of Fe in the catalyst. Ⅱ / Ⅲ with Mo Ⅳ / Ⅴ / Ⅵ The redox cycle improved catalytic activity and enhanced the reaction of ·OH and ·O2. - SO4 - , 1The generation of active species such as O2 promotes the degradation of OFX.
[0098] 4. Cyclic stability test:
[0099] The electrode material MIL101(Fe)@Mel-MoPc / BC prepared in Example 1 was used to construct a reaction system according to the above method. PMS and OFX were added to the reaction system to make the final concentration of PMS 0.5 mM and the concentration of OFX 10 mg / L. Under the same experimental conditions, the cathode was subjected to 9 cycles of testing.
[0100] The results are as follows Figure 7 As shown, the degradation rate of OFX decreased by only 7.61% after 9 cycles, indicating that the cathode has good cycle stability.
[0101] 5. The degradation effect of different electrode materials on OFX:
[0102] The electrode materials MIL101(Fe)@Mel-MoPc / BC prepared in Example 1, MIL101(Fe) / BC prepared in Comparative Example 2, and Mel-MoPc / BC prepared in Comparative Example 3 were used to construct reaction systems according to the above method. PMS and OFX were added to the reaction systems to make the final concentration of PMS 0.5 mM and the concentration of OFX 10 mg / L. The current was set at 300 mA. The effect of different electrode materials on the degradation effect of OFX was investigated. A control group was used with no electrode material added and only PMS added.
[0103] The results are as follows Figure 8 As shown, the degradation efficiency of OFX by persulfate alone was only 5.8%, while the degradation rate of OFX by MIL101(Fe) / BC activated PMS was 56.4%, the degradation rate of OFX by Mel-MoPc / BC activated PMS was 30.8%, and the degradation rate of OFX by MIL101(Fe)@Mel-MoPc / BC activated PMS was 92.6%. These results demonstrate that the electrode material prepared in this invention can activate persulfate, improving its degradation effect on OFX; and that MIL101(Fe) and Mel-MoPc have a synergistic effect on activating PMS for OFX degradation.
[0104] 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. An electrode material based on MOF@COF / BC, characterized in that, It is prepared by the following method: (1) NH2-MIL101(Fe), melamine and molybdenum phthalocyanine were dissolved in dimethyl sulfoxide and reacted at 160-200℃ for 10-14h. After the reaction, the precipitate was collected, washed and dried to prepare NH2-MIL101(Fe)@Mel-MoPc. (2) Biochar and NH2-MIL101(Fe)@Mel-MoPc were mixed in deionized water, ultrasonically treated for 8-12 min, stirred for 10-14 h, and then the precipitate was collected by centrifugation, washed and dried to prepare electrode material.
2. The electrode material according to claim 1, characterized in that, In step (1), the mass ratio of NH2-MIL101(Fe), melamine and molybdenum phthalocyanine added is (0.33-1.5):(0.165-0.33):(0.335-0.67).
3. The electrode material according to claim 1, characterized in that, In step (2), the biochar is prepared by the following method: Rice husks were placed in a tube furnace and heated to 500°C at a rate of 5°C / min under a nitrogen atmosphere, and held for 2 hours.
4. The electrode material according to claim 1, characterized in that, In step (2), the mass ratio of biochar to NH2-MIL101(Fe)@Mel-MoPc is 2:
1.
5. The use of the electrode material according to any one of claims 1-4 in (1) or (2) below: (1) Activation of persulfate; (2) Degradation of antibiotics; The degradation of antibiotics is achieved by electrochemically activating PMS to generate active species using the electrode material described in any one of claims 1-4 as the cathode, 50 mM Na2SO4 as the electrolyte, and adding PMS to a final concentration of 0.5 mM; the active species is SO42-. - ·OH, ·O2 - and 1 O2.
6. The application according to claim 5, characterized in that, The antibiotic in question is ofloxacin.
7. An electrochemical system for degrading ofloxacin, characterized in that, include: Anode, cathode, and electrolyte; The anode is a graphite electrode; The cathode is prepared by the following method: The electrode material described in any one of claims 1-4 is mixed with carbon black, and then polyvinylidene fluoride and N-methylpyrrolidone are added and ground into a paste. The paste is then coated on both sides of graphite paper to prepare a cathode. The electrolyte is 50 mM Na2SO4; PMS was added to the electrochemical system to achieve a final concentration of 0.5 mM.
8. A method for degrading ofloxacin in wastewater using the electrochemical system described in claim 7, characterized in that, Includes the following steps: The cathode and anode are installed in an electrolytic cell containing electrolyte. Wastewater to be treated is added to the electrolytic cell, and PMS is added to adjust the pH of the system to 7. The current is controlled at 300-900mA to degrade ofloxacin in the wastewater.